SYSTEMS AND METHODS FOR A HYDRAULIC TOOL

Abstract

A knockout punch tool includes a housing, a working head with a cutting die, a hydraulic circuit with an actuator to move the cutting die, a pump providing pressurized fluid, a pressure sensor, a fluid reservoir, and a controller. The controller monitors pressure during knockout operations, determines completion when pressure exceeds a first threshold indicating cutting has started then drops below a second threshold, determines when pressure derivative is at or near zero, verifies the derivative remains near zero for a preset time, and automatically initiates a hydraulic dump sequence to release pressurized fluid back to the reservoir, retracting the cutting die to home position.

Claims

1. A knockout punch tool, comprising: a housing; a working head coupled to the housing and including a cutting die to perform a knockout operation on a workpiece; a hydraulic circuit including a hydraulic actuator to move the cutting die; a pump providing pressurized hydraulic fluid to the hydraulic circuit; a pressure sensor to measure pressure within the hydraulic circuit; a fluid reservoir; and a controller to: monitor pressure measurements from the pressure sensor during the knockout operation, determine that the knockout operation is complete when: the pressure measurements from the pressure sensor exceed a first threshold indicating a cutting operation has started; and the pressure measurements from the pressure sensor subsequently drop below a second threshold lower than the first threshold; determine when a pressure derivative based on the measured pressure is at or near zero; verify that the pressure derivative remains at or near zero for a preset amount of time; and automatically initiate a hydraulic dump sequence to release pressurized hydraulic fluid from the hydraulic circuit back to the fluid reservoir to retract the cutting die to a home position.

2. The knockout punch tool of claim 1, wherein the preset amount of time is in a range of about 50 milliseconds to about 250 milliseconds.

3. The knockout punch tool of claim 1, wherein the controller is further configured to: implement a buffer counter that increments when the pressure derivative is at or near zero and decrements when the pressure derivative moves outside a zero range.

4. The knockout punch tool of claim 3, wherein the controller decrements the buffer counter at a higher rate than it increments the buffer counter.

5. The knockout punch tool of claim 1, wherein the controller is further configured to: store a maximum cut pressure corresponding to a maximum pressure measured from initiation of the knockout operation until determination that the knockout operation is complete; and store a maximum cycle pressure corresponding to a maximum pressure measured during an operational cycle.

6. The knockout punch tool of claim 1, further comprising: a trigger coupled to the housing; and the controller to initiate the knockout operation in response to actuation of the trigger.

7. The knockout punch tool of claim 1, wherein the first threshold serves as a cut start threshold that distinguishes between initial system pressurization and higher pressures developed when the cutting die encounters resistance from the workpiece.

8. A method of operating a knockout punch tool having a cutting die, a hydraulic circuit, and a pressure sensor, the method comprising: initiating a knockout operation by activating a pump to provide pressurized hydraulic fluid to the hydraulic circuit to move the cutting die; monitoring pressure measurements from the pressure sensor during the knockout operation; determining that a cutting operation has started when the pressure measurements exceed a first threshold; determining that a workpiece has been cut when the pressure measurements subsequently drop below a second threshold that is lower than the first threshold; monitoring a pressure derivative after determining that the workpiece has been cut; determining when the pressure derivative is at or near zero; verifying that the pressure derivative remains at or near zero for a preset amount of time using a buffer counter; and automatically initiating a hydraulic dump sequence to release pressurized hydraulic fluid from the hydraulic circuit back to a fluid reservoir to retract the cutting die to a home position after the verification is complete.

9. The method of claim 8, wherein the preset amount of time is in a range of about 50 milliseconds to about 250 milliseconds.

10. The method of claim 8, wherein the buffer counter increments when the pressure derivative is at or near zero and decrements when the pressure derivative moves outside a zero range.

11. The method of claim 10, wherein the buffer counter decrements at a higher rate than it increments.

12. The method of claim 8, further comprising: storing a maximum cut pressure corresponding to a maximum pressure measured from initiation of the knockout operation until determination that the knockout operation is complete.

13. The method of claim 12, further comprising: storing a maximum cycle pressure corresponding to a maximum pressure measured during an operational cycle.

14. The method of claim 8, wherein the first threshold serves as a cut start threshold that distinguishes between initial system pressurization and higher pressures developed when the cutting die encounters resistance from the workpiece.

15. A knockout punch tool, comprising: a housing; a working head coupled to the housing and including a cutting die; a hydraulic actuator to move the cutting die during a knockout operation; a hydraulic circuit in fluid communication with the hydraulic actuator; a pressure sensor in communication with the hydraulic circuit; a controller configured to receive pressure measurements from the pressure sensor and determine completion of the knockout operation based on the pressure measurements; and an automatic blade retraction mechanism controlled by the controller and configured to automatically retract the cutting die to a home position upon determination that the knockout operation is complete, the controller causing the automatic blade retraction mechanism to initiate a hydraulic dump sequence that releases pressurized hydraulic fluid from the hydraulic circuit back to a fluid reservoir.

16. The knockout punch tool of claim 15, wherein the controller is configured to determine completion of the knockout operation by: detecting when pressure measurements exceed a first threshold indicating a cutting operation has started and subsequently drop below a second threshold.

17. The knockout punch tool of claim 16, wherein the controller is further configured to monitor a pressure derivative after the pressure measurements drop below the second threshold and determine when the pressure derivative is at or near zero.

18. The knockout punch tool of claim 17, wherein the controller is configured to verify that the pressure derivative remains at or near zero for a preset amount of time before initiating the hydraulic dump sequence.

19. The knockout punch tool of claim 18, wherein the controller implements a buffer counter that increments when the pressure derivative is at or near zero and decrements when the pressure derivative moves outside a zero range.

20. The knockout punch tool of claim 15, wherein the controller is further configured to store a maximum cut pressure corresponding to a maximum pressure measured from initiation of the knockout operation until determination that the knockout operation is complete.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of embodiments of the invention:

[0024] FIG. 1 is a side view of one example of a hydraulic tool according to aspects of the present disclosure.

[0025] FIG. 2 is a cross-sectional view of an example cutting assembly for use with the hydraulic tool of FIG. 1.

[0026] FIG. 3 is a diagrammatic view of components of a hydraulic and electronic control system of the hydraulic tool of FIG. 1.

[0027] FIG. 4A is a flowchart of an example cut process of the hydraulic tool of FIG. 1.

[0028] FIG. 4B is a graph corresponding to the process shown in FIG. 4A.

[0029] FIG. 5A is a flowchart of another example cut process of the hydraulic tool of FIG. 1.

[0030] FIG. 5B is a graph corresponding to the process shown in FIG. 5A.

[0031] FIG. 6A is a flowchart of yet another example cut process of the hydraulic tool of FIG. 1.

[0032] FIG. 6B is a graph corresponding to the process shown in FIG. 6A.

[0033] FIG. 7A is a flowchart of yet another example cut process of the hydraulic tool of FIG. 1.

[0034] FIG. 7B is a graph corresponding to the process shown in FIG. 7A.

[0035] FIG. 8 is an axonometric view of another example of a hydraulic tool according to aspects of the present disclosure.

[0036] FIG. 9 is a diagrammatic view of yet another example of a hydraulic tool according to aspects of the present disclosure.

DETAILED DESCRIPTION

[0037] The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Given the benefit of this disclosure, various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein.

[0038] The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.

[0039] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of including, comprising, or having and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms mounted, connected, supported, and coupled and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, connected and coupled are not restricted to physical or mechanical connections or couplings.

[0040] In some examples, a hydraulic tool may include an automatic blade retraction mechanism that automatically retracts a blade of the hydraulic tool (e.g., back into a home position). For example, the automatic blade retraction mechanism may retract the blade after the hydraulic tool completes a cut (or crimp, or knockout, or other work operation) to mitigate force or pressure on the tool, which may improve overall reliability of the tool. For example, in use, the hydraulic tool may be configured to monitor a work operation on a workpiece, and the blade retraction mechanism can automatically dump hydraulic fluid from a hydraulic chamber back into a reservoir (e.g., a fluid retention location) once the cut is completed. In some examples, during the work operation, the hydraulic tool may record both a maximum cut pressure (e.g., a maximum pressure needed to cut the workpiece) and a maximum cycle pressure (e.g., a maximum pressure reached during the work operation).

[0041] With reference to FIG. 1, a hydraulic tool 100 according to an example of the present disclosure is shown. In one example, the hydraulic tool 100 may be a cutting tool. However, in other examples, the hydraulic tool may be a knockout tool (e.g., a knockout punch 800) or any other type of hydraulic tool (e.g., hydraulic tool 900). The hydraulic tool 100 includes a housing 102 that receives a cutter assembly 104 having a head 106 and a body 108. In one example, the body 108 of the assembly 104 may be positioned within the housing 102 of the tool 100 while the head 106 of the assembly 104 is positioned outside of the housing 102. The housing 102 may further include a handle 110 to permit a user to grip and maneuver the tool 100. In one example, the handle 110 extends substantially perpendicular to the head 106. However, in other examples, the handle 110 may extend substantially parallel to the head 106 (e.g., in line with the head 106). In some examples, the user may activate or deactivate operation of the tool 100 via activation of an actuator. In some examples, the actuator may be in the form of a trigger 112 positioned on the handle 110. However, in other examples, tool 100 can be controlled using a remote device or using a mobile application (e.g., on a mobile phone or laptop), although other configurations are possible.

[0042] In some examples, to control operation of the tool 100, a user activates the tool 100 by depressing the trigger 112. Correspondingly, the tool 100 may be deactivated by releasing the trigger 112. In one particular example, the tool 100 includes a battery receptacle 114 configured to receive and secure a battery (e.g., a rechargeable lithium ion battery, etc.) to power the tool 100 (such as the battery 156 illustrated in FIG. 3). However, in other examples, the tool 100 may include a power cord to supply power to the tool 100.

[0043] In some examples, the head 106 of the assembly 104 generally defines a U-shape, though the head 106 may define other geometries, such as a C-shape, or others. For example, FIG. 2 illustrates another example of a cutter assembly 120, that may be used with the hydraulic tool 100 of FIG. 1.

[0044] As shown in FIG. 2, the head 106 of the cutter assembly 120 includes a first frame 122 and a second frame 124. The second frame 124 is moveable relative to the first frame 122 so that the tool head 106 can be opened to insert a workpiece into a cutting zone 126. In some examples, the tool head 106 can be moved into a closed position in order to facilitate cutting the workpiece in the cutting zone 126. The tool head 106 further includes a first blade and a second blade within the respective first and second frames 122, 124. For example, the tool head 106 includes a first blade 128 slidably disposed in the first frame 122 and a second blade 130 coupled to the second frame 124. The first blade 128 is moveable from a proximal end of the cutting zone 126 toward the second blade 130 at a distal end of the cutting zone 126. Accordingly, the first blade 128 and the second blade 130 provide a guillotine-type cutting action. However, in other examples, the first and second blades 128, 130 may be arranged to provide other cutting actions (e.g., shear-type actions, scissor-type actions, etc.).

[0045] In some examples, a hydraulic actuator assembly is coupled to a proximal end 132 of the head 106 and is configured to move the first blade 128 toward the second blade 130 to cut an object (e.g., a workpiece) positioned in the cutting zone 126. For example, the actuator assembly includes a pump configured to provide pressurized hydraulic fluid to a hydraulic circuit and a ram configured to move the first blade 128. In some examples, the pump provides pressurized hydraulic fluid, which moves the ram to provide corresponding movement to the first blade 128 across the cutting zone 126, towards the second blade 130.

[0046] Turning now to FIG. 3, a hydraulic and electronic control system 140 of the hydraulic tool 100 is shown. The hydraulic and electronic control system 140 may include one or more user interface components 142, a controller 144, a memory 146, a fluid reservoir 148 in fluid communication with a hydraulic circuit 150 and a pump 152, a pressure sensor 154, a battery 156, a motor 158, and a gear reducer 160.

[0047] In some examples, the user interface component(s) 142 is configured to provide input to the power tool 100, such as to the controller 144 of the power tool 100. In particular, in this example, the user interface components 142 include the trigger 112 (see, e.g., FIG. 1), an operator panel, one or more switches, one or more push buttons, one or more interactive indicating lights, soft touch screens or panels, other types of similar switches, or any combination thereof.

[0048] The controller 144 (which may also be referred to as a motor control unit or a motor inverter) includes a processor and is connected to the memory 146, the user interface component(s) 142, the hydraulic circuit 150, the pump 152, and the pressure sensor 154, and is powered by the battery 156. For example, the hydraulic circuit 150, the pump 152, or the pressure sensor 154 are configured to provide certain operating information and operational data to the controller 144, as further described below. Furthermore, in some examples, the controller 144 can include a printed circuit board assembly (PCBA). In some examples, the memory 146 is a non-transitory computer readable medium and includes a program storage area and a data storage area. In particular, the data storge area includes a plurality of look up table of values. For example, at least one stored look up table may include work piece information or data, such as maximum fluid pressures in the hydraulic circuit 150, as further described below. The program storage area and the data storage area can include combinations of different types of memory, such as a ROM, a RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The program storage area includes instructions that, when executed by the processor, cause the controller 144 to operate the tool 100.

[0049] In some examples, the electric motor 158 is powered by the battery 156 and is controlled by the controller 144. Furthermore, the electric motor 158 is configured to drive the pump 152 by way of the gear reducer 160. In particular, the pump 152 is driven to draw fluid from the fluid reservoir 148 (e.g., generally stored around or at atmospheric pressure), to pressurize the fluid, and deliver the fluid to the hydraulic circuit 150. For example, when a user depresses the trigger 112 to perform a work operation with the tool 100 (e.g., a cutting operation), the pump 152 is driven to provide pressurized hydraulic fluid to the hydraulic circuit 150. The pressurized hydraulic fluid within the hydraulic circuit then drives the ram of a hydraulic actuator cylinder within the hydraulic circuit 150 toward the head 106 to move the first blade 128 from a most proximal position (e.g., a home position, as illustrated in FIG. 2), across the cutting zone 126 toward a most distal position adjacent the second blade 130 (e.g., a closed position).

[0050] Additionally, in some examples, during the work operation, a pressure of the hydraulic fluid within the hydraulic circuit 150 is monitored by the controller 144 via the pressure sensor 154. That is, the pressure sensor 154 (e.g., pressure transducer) is in communication with the fluid distribution network, such as located within the hydraulic circuit 150. In particular, the pressure sensor 154 is configured to provide measurements to the controller 144 indicative of a pressure within the hydraulic circuit 150.

[0051] Generally, when the work operation is complete, the user releases the trigger 112, which causes the controller 144 to stop the motor 158. When the motor 158 stops, the tool 100 pauses the ram and maintains the hydraulic pressure at its current level. In some examples, to release the high pressure fluid from the hydraulic circuit 150 back to the fluid reservoir 148, the tool 100 can include a second trigger that may be actuated by a user to initiate a hydraulic dump sequence. Alternatively, in other examples, users may continue to drive the motor 158 until deadhead or bottoming out occurs which automatically triggers a hydraulic dump sequence but may cause unwanted wear and tear on the tool. In some examples, the hydraulic dump sequence includes opening one or more valves within the hydraulic circuit 150 (e.g., in response to instructions from the controller 144) to permit the pressurized fluid to release back to (e.g., return to) the fluid reservoir 148. As such, the hydraulic dump sequence, in some examples, is configured to be an electronics-based sequence controlled by the controller 144.

[0052] In an example operation of the cutter assembly 120 shown in FIG. 2, in which the cutting head 106 includes the first blade 128 and the second blade 130, the head 106 completes a work operation when the first blade 128 and the second blade 130 are in the closed position after the workpiece has been cut. More generally, the closed position may be a position in which blades 128, 130 of the head 106 are at a minimum distance relative to each other. For simplicity, the following discussion will refer to the cutter assembly 120, first blade 128, and second blade 130.

[0053] According to some examples, the hydraulic tool 100 is configured to automatically determine when a work operation (e.g., a cutting operation, crimping operation, etc.) is complete and, upon such determination, retract the first blade 128 into the home position. More specifically, upon such determination, the hydraulic tool 100 releases the high pressure fluid from the hydraulic circuit 150 back to the fluid reservoir 148 to permit the first blade 128 to retract back to the home position, as noted above. For example, the controller 144 determines a status of the work operation based on pressure signals from the pressure sensor 154 and controls automatic blade retraction based on these pressure signals.

[0054] FIGS. 4A-7B illustrate flowcharts and graphical representations of example processes that use pressure sensor readings as feedback during a work operation. Generally, one or more stages of these processes is incorporated into low-level firmware algorithms embedded within the controller 144. The firmware can be a basic input/output system (BIOS), an extensible firmware interface (EFI), or another type of firmware. In some examples, a high-level firmware algorithm can be used. In particular, the high-level firmware algorithm is configured to be deployed within a flash memory chip and allows for updates to be made. In still further examples, the algorithm can be implemented within subsystems. These subsystems are configured to be semi-independent devices that are part of a more extensive system.

[0055] More specifically, FIG. 4A illustrates an example process 170 that uses measured pressure values and predetermined thresholds to initiate automatic blade retraction, with a corresponding graph 172 (see, e.g., FIG. 4B) illustrating pressure measurements over time during the execution of the process 170. As shown in FIG. 4A, at stage 174 the user activates the tool via actuation of the actuator (e.g., pressing the trigger 112). In some examples, activation of the actuator includes detection that the trigger 112 has been pulled which is sensed by the controller 144 and initiates startup of the motor 158 at stage 174 (e.g., see T1 on graph 172). After the motor 158 is started, the motor 158 drives the pump 152 to begin pressurizing the hydraulic circuit 150, causing hydraulic fluid to flow from the reservoir 148 through the circuit 150 to initiate movement of the first blade 128 towards the second blade 130.

[0056] During operation of the motor 158, the controller 144 continually monitors whether pressure in the hydraulic circuit 150 has exceeded a first threshold 176, which indicates that a cutting operation has started at stage 178 (e.g., see T2 on graph 172). In this way, the first threshold 176 serves as a cut start threshold that distinguishes between initial system pressurization and the higher pressures developed when the first blade 128 encounters resistance from a workpiece positioned in the cutting zone 126. In particular, the controller 144 receives pressure measurements from the pressure sensor 154 at regular intervals and compares these measurements against the first threshold 176, which are stored in memory 146 as a predetermined value based on the operational characteristics of the tool and workpiece properties. At stage 178, the controller 144 is configured to raise a flag in the firmware to indicate that the cut threshold 176 has been passed, providing a status indicator for subsequent process stages.

[0057] During the cutting operation, at stage 180, the controller 144 continually monitors the hydraulic circuit 150 pressure and checks whether the pressure has dropped below a second threshold 182 (e.g., see T3 on graph 172). In some examples, a pressure drop below the second threshold 182 indicates that the workpiece has been cut, as the resistance force applied by the workpiece is released when the workpiece is severed. In this way, the second threshold 182 functions as a cut end threshold and is set at a pressure value lower than the first threshold 176. As noted above with regard to the first threshold 176, the controller 144 receives ongoing pressure measurements from the pressure sensor 154 and compares these values against the second threshold 182 stored in memory 146. When the controller 144 determines that the cut end threshold 182 has been passed, the controller 144 can raise a flag in the firmware indicating the cut end threshold has been passed to indicate this status change.

[0058] After the controller 144 determines that the workpiece has been cut, the process 170 advances to stage 184 where the controller 144 continually monitors a pressure derivative (e.g., configured as a ramp rate) to determine whether the derivative is at or near zero. The pressure derivative monitoring at stage 184 serves as an additional verification step to ensure that the cutting operation has been completed. For example, if the pressure derivative is not close to zero, this indicates that the hydraulic circuit 150 is still experiencing pressure changes and may be continuing to build pressure (e.g., is continuing to cut). In some examples, when the pressure derivative is near to zero, this indicates that there is no pressure building in the system, as the workpiece is no longer applying a counterforce to the blade(s).

[0059] In some examples, a buffer counter (e.g., a timer) may be implemented to verify that a cutting process is completed prior to initiating a dump sequence. This is particularly valuable for cutting operations involving workpieces such as stranded cable where the pressure derivative may drop to zero momentarily as the blades 128, 130 initially serve a strand of the cable, but then resume cutting once contacting another strand of the cable. This monitoring further prevents premature determination of cut completion in cases where partial cutting has occurred or where the workpiece material characteristics cause complex pressure response patterns during the severing process. The pressure derivative calculation may involve comparing successive pressure measurements over time to determine the rate of pressure change within the hydraulic circuit 150.

[0060] Once the pressure derivative is at or near zero (e.g., indicating that the workpiece has been cut), the firmware increments the buffer counter and the process 170 advances to stage 186. At stage 186, the controller 144 determines whether the buffer is full (e.g., a timer has expired), which corresponds to verifying that the pressure derivative has remained at or near zero for a preset amount of time. This time-based verification ensures that the pressure stabilization is sustained rather than temporary, further verifying that the cutting operation has been fully completed and that the hydraulic circuit 150 has reached a stable operating condition. In this example, the preset amount of time is configured to be in a range of about 50 milliseconds to about 250 milliseconds, although other time intervals may be selected based on tool characteristics, workpiece types, and operational requirements. When the pressure derivative moves outside the zero range (e.g., is greater than or less than zero), indicating that the tool 100 is building or dropping pressure, the firmware may decrement the buffer counter to account for pressure instability. In some implementations, the buffer may reset to zero when pressure variations are detected, or the firmware may decrement the buffer at a higher rate than it increments, such as decrementing by two milliseconds for each millisecond outside the zero pressure derivative range while only incrementing by one millisecond for each millisecond within the zero range. If the controller 144 determines that the pressure derivative has not remained at zero for the preset amount of time, the process 170 loops back to stage 184 where the controller 144 continually monitors the pressure derivative.

[0061] Once the pressure derivative or ramp rate has been at zero for the preset amount of time, the controller 144 determines that the cut has been completed at stage 188. The completion determination initiates the hydraulic dump sequence, which returns pressurized hydraulic fluid back to the reservoir 148, and retracts the first blade 128 back into a home position. Furthermore, at stage 188, the controller 144 clears the buffer counter and resets the status flags in the firmware. Accordingly, at stage 188, an operation reset is performed which indicates that the tool 100 is ready for another work operation.

[0062] The pressure release of the process 170 can permit the tool 100 to avoid deadhead or bottoming out after the workpiece has been cut, which may cause excessive pressure buildup and premature wear on system components. For example, execution of the process 170 and initiation of the dump sequence once the buffer verification is complete can mitigate pressure jumps in the hydraulic circuit 150, illustrated at section 190 in the graph 172. By mitigating the risk of these pressure spikes and associated mechanical stresses, the process 170 may further increase the useful life of the tool 100, while improving operational reliability and stability.

[0063] FIG. 5A and 5B illustrate another example process 192 that uses pressure derivatives to initiate automatic blade retraction, with a corresponding graph 194 illustrating pressure measurements over time during the process 192. As shown in FIG. 5A, the process 192 begins at stage 196, which includes activation of an actuator. In this example, activation of the actuator includes the trigger 112 pull, which initiates the startup of the motor 158, and subsequent pressure rise in the hydraulic circuit 150. At stage 202, the first blade 128 cuts through the workpiece which causes a pressure drop in the hydraulic circuit 150 and indicated by arrows 200 in the graph 194 of FIG. 5B. At stage 206, the controller 144 continually monitors the pressure in the circuit 150 and determines when the pressure drops at a rate that exceeds a predetermined rate threshold 204 indicating the cutting operation is completed. Based on this determination, at stage 208, the motor 158 is stopped and the hydraulic dump sequence is initiated. In some examples, the hydraulic dump sequence is initiated automatically without requiring the user to release the trigger 112. The process 192 then proceeds to stage 210 where an operation reset indicates the tool 100 is ready for another work operation is performed.

[0064] The pressure release of the process 192 can permit the tool 100 to avoid deadhead after the workpiece has been cut. For example, execution of the process 192 can prevent pressure jumps in the hydraulic circuit 150, illustrated at section 212 in the graph 194, after the workpiece has already been cut, which may extend the useful life of the tool 100 and improve operational reliability.

[0065] FIGS. 6A and 6B illustrates yet another example process 214 that uses pressure derivatives to initiate automatic blade retraction, with a corresponding graph 216 illustrating pressure measurements over time during the process 214. As shown in FIG. 6, the process 214 starts at stage 218 with activation of an actuator. In this example, activation of the actuator includes the trigger 112 pull which initiates the motor 158 startup and pressure rise in the hydraulic circuit 150. The process 214 proceeds to stage 220 where the first blade 128 cuts through the workpiece, which causes a pressure drop in the circuit 150. Once a piston or ram within the hydraulic circuit 150 reaches an end of its stroke, a pressure rises in the circuit 150 at stage 222. The process 214 then proceeds to stage 226 where the controller 144 monitors the pressure in the circuit 150 and detects when the pressure rises at a sharp enough rate that exceeds a predetermined rate threshold 224, which indicates that the tool 100 has reached a deadhead condition and initiates the dump sequence. This deadhead condition occurs when the hydraulic system encounters maximum resistance, which may result from completion of a cutting operation or from actuating the tool 100 without a workpiece positioned in the blades 128, 130. At stage 228, the motor 158 is stopped and trigger 112 is released. The process 214 then proceeds to stage 230 where an operation reset indicates that the tool 100 is ready for another work operation.

[0066] The pressure release of the process 214 allows the tool 100 to avoid deadhead after the workpiece has been cut. For example, execution of the process 214 prevents pressure jumps in the hydraulic circuit 150, illustrated at section 232 in the graph 216, after the workpiece has already been cut and the first blade 128 has reached the closed position and can no longer move distally. This, in turn, protects the system components of the tool 100 and extends tool 100 life.

[0067] FIGS. 7A and 7B illustrate yet another example process 234 that uses pressure thresholds during a work operation, with a corresponding graph 236 illustrating pressure measurements over time during the process 234. As shown in FIG. 7A, the process 234 begins at stage 238 with activation of an actuator. In this example, the activation of the actuator includes the trigger 112 pull, which initiates the motor 158 startup, and begins a pressure rise in the circuit 150. At stage 242, the pressure in the hydraulic circuit 150 passes a first threshold 240 that indicates a cutting operation has started. At stage 244, the first blade 128 cuts through material of the workpiece that causes a pressure drop in the circuit 150. At stage 246, the actuator is deactivated. In this example, deactivation of the actuator includes the trigger 112 being released. After release of the trigger 112, the process 234 then proceeds to stage 248 where a hydraulic dump operation is initiated, as well as operation reset indicating the tool 100 is ready for another work operation.

[0068] According to the process 234 of FIG. 7A, if the user does not release the trigger 112 (e.g., stage 246 does not occur), the tool 100 may continue to run to deadhead conditions, as shown at section 250 by the large pressure changes at the end of the graph 236. This highlights the importance of user intervention in process 234, where manual trigger 112 release serves as the primary mechanism for initiating the dump sequence and prevents excessive pressure buildup and potential system damage after cutting completion.

[0069] FIGS. 4-7 each illustrate an implementation of algorithms with a linear sequence of events. The algorithm restarts after completion. However, in other implementations, one or more of these algorithms can be modified to include a while loop, for loop, or other firmware element, where the loops would allow the process to continue running until all conditions to stop are met. Additionally, in some implementations, different relevant measurements are taken in series. However, in further implementations, measurements can be taken at the same time or in a different order.

[0070] In light of the above, according to some examples, a hydraulic tool 100 utilizes pressure measurements and thresholds to initiate automatic blade retraction after the hydraulic tool 100 completes a cut or crimp, by automatically dumping fluid from its hydraulic circuit 150 back to its fluid reservoir 148, to mitigate force or pressure on the tool 100. Accordingly, one benefit of this feature is that it prevents the tool 100 from reaching a maximum force or quality pressure after each cut, thereby potentially helping improve reliability of the tool 100. In some examples, each of the thresholds described above may be a single threshold stored in memory 146. In other examples, each threshold may comprise a plurality of thresholds stored in a look-up table in memory 146, and the controller 144 can retrieve a respective threshold from the look-up table based on particular operating variables, such as cut/crimp type, workpiece material type, etc.

[0071] Additionally, in some examples, the hydraulic tool 100 monitoring pressure over the course of a work operation can provide additional benefits. For example, during the work operation, the controller 144 can store in memory 146 both a maximum cut/crimp pressure (e.g., a maximum pressure needed to cut/crimp the workpiece) and a maximum cycle pressure (e.g., a maximum pressure reached during the work operation).

[0072] For example, generally, when a user cuts a material and then continues to extend the ram in the hydraulic circuit 150 until deadhead, a tool 100 may log the maximum cycle or quality pressure sensed until the trigger 112 is released. This maximum pressure, however, may not be the pressure the tool 100 required to cut the material. By way of example, referring back to FIG. 4, a maximum cycle pressure 252 is shown in the graph 172. This maximum cycle pressure 252 is reached after the workpiece has already been cut. On the other hand, a maximum cut/crimp pressure 254 is also shown in FIG. 4, indicating a maximum pressure sensed during the work operation, which is less than the maximum cycle pressure 252.

[0073] As these are often two different pressures, with the maximum cycle pressure 252 generally larger than the maximum cut pressure 254, the controller 144 can store both pressures 252, 254 in memory 146. In some examples, these pressures 252, 254 can be stored in a look-up table in memory 146. Such data can be beneficial for both engineering and service. For example, the data can be used for determining what kind of cables are being cut to assist with optimizing threshold settings. As another example, that data can help set better day-in-the-life cycles for life testing of the tool 100.

[0074] Accordingly, during a work operation, when pressure measurements indicate a cut is completed, the controller 144 can store a maximum pressure of the cycle up to that point (e.g., from when the trigger 112 is depressed to when the respective threshold is met) as the maximum cut pressure 254 in memory 146. For example, this may occur at stage 184 of FIG. 4, at stage 206 of FIG. 5, and stage 226 of FIG. 6. When the overall cycle is completed, such as at stage 188 of FIG. 4, at stage 210 of FIG. 5, at stage 230 of FIG. 6, or at stage 248 of FIG. 7, the controller 144 can store an overall maximum pressure of the cycle (e.g., from when the trigger 112 is depressed to when the trigger 112 is released) as the maximum cycle pressure 252 in memory 146.

[0075] FIG. 8 illustrates another example of a hydraulic tool in the form of a knockout punch 800. As will be recognized, the knockout punch 800 shares a number of components in common with and operates in a similar fashion to the examples illustrated and described previously (e.g., the hydraulic tool 100). For the sake of brevity, these common features will not be again described below in detail. Rather, previous discussion of commonly named or numbered features, unless otherwise indicated, also applies to example configurations of the knockout punch 800. Further, as should be appreciated, the processes laid out in FIGS. 4A-7B with respect to hydraulic tool 100 also apply similarly to the knockout punch 800.

[0076] In some examples, the knockout punch 800 includes a housing 804 and a working head 808 that is coupled to the housing 804 to perform an operation on a work piece. In some examples, the working head 808 may include one or more blades (e.g., cutting dies, etc.) used to perform the work operation on the work piece. As mentioned previously, the working head 808 is illustrated as a knockout punch (e.g., including a punch die forming a cutting head). However, other types of working heads can also be used.

[0077] In some examples, the knockout punch 800 can be battery-operated and the housing 804 can define a battery receptacle 812 that is configured to receive a battery 816. In other examples the knockout punch 800 can include a power cord (e.g., for connection to an electrical socket, etc.). To operate the knockout punch 800, a trigger 820 is coupled to the housing 804. The trigger 820 can be manipulated by an operator to actuate the knockout punch 800 and perform the work operation (e.g., to draw a portion of a die through a work piece to knockout a hole, etc.). For example, the trigger 820 can be actuated by the operator to control movement of the working head 808, which may in turn perform the work operation on a workpiece. As should be appreciated, following or during the work operation, the knockout punch 800 may perform any of the blade retraction processes discussed above in FIGS. 4A-7B.

[0078] FIG. 9 illustrates another example of a hydraulic tool 900. As will be recognized, the hydraulic tool 900 shares a number of components in common with and operates in a similar fashion to the examples illustrated and described previously (e.g., the hydraulic tool 100, knockout punch 800, etc.). For the sake of brevity, these common features will not be again described below in detail. Rather, previous discussion of commonly named or numbered features, unless otherwise indicated, also applies to example configurations of the hydraulic tool 900. Further, as should be appreciated, the processes laid out in FIGS. 4A-7B with respect to hydraulic tool 100 also apply similarly to the hydraulic tool 900.

[0079] As mentioned previously, the hydraulic tool 900 includes a housing and a working head (e.g., including one or more cutting elements, such as blades, dies, etc.) that are coupled to the housing to perform an operation (e.g., crimp, cut, knockout, etc.) on a work piece. In some examples, the hydraulic tool 900 may include a power source 912 in order to permit operation of the tool 900. In some examples, the tool 900 can be battery-operated and the power source 912 may be in the form of a battery 916 (e.g., a removable, rechargeable battery). In other examples the hydraulic tool 900 can include a power cord (e.g., for alternating current (AC) power connections).

[0080] To operate the hydraulic tool 900, a trigger 920 may be coupled to the housing. The trigger 920 can be manipulated by a user to actuate the hydraulic tool 900 and perform the work operation. For example, actuating the trigger 920 can control operation of an output assembly that is disposed within the housing. The output assembly can include a motor 928, a pump 906, and a hydraulic actuator 936 that acts on the working head to perform the work operation. When the trigger 920 is pressed, electrical current can flow from the battery 916 to the output assembly, causing the output assembly to operate the working head to perform the work operation.

[0081] In some cases, the trigger 920 can communicate with an electronic controller 940 (e.g., including a processor and a memory) that controls a flow of electrical current from the battery 916 or another power source. More specifically, the electrical current can be provided to the motor 928 of the output assembly. The motor 928 can be coupled to the pump 906 so that rotation of the motor 928 operates the pump 906 to supply pressurized hydraulic fluid to the hydraulic actuator 936. In some cases, the motor 928 can be coupled to the pump 906 via a transmission (e.g., a gear reducer).

[0082] In some examples, the pump 906 can supply hydraulic fluid from a reservoir 948 (e.g., a tank) to a hydraulic cylinder 905. In general, the hydraulic cylinder 905 includes a piston 956 having piston head 958 and a piston rod 960. The piston 956 is moveably received in the cylinder 905 to form a first chamber 972 and a second chamber 980 within an internal volume of the cylinder 905. In some cases, a piston seal is provided to seal between the piston head 958 and the cylinder 905 to prevent fluid from leaking between the first chamber 972 and the second chamber 980. Further, a rod seal is provided to seal between the cylinder 905 and the piston rod 960 to prevent hydraulic fluid from leaking out of the cylinder 905.

[0083] To operate the hydraulic actuator 936, the hydraulic cylinder 905 uses pressurized fluid to create mechanical motion. For example, hydraulic fluid is pumped into the first chamber 972. The pressure acting on the surface area of the piston 956 generates a force that causes the piston 956 to move within the cylinder 905 between a first position (e.g., a retracted position or an extended position) and a second position (e.g., the other of the retracted position and the extended position). In some cases, the hydraulic cylinder 905 is single acting. For example, hydraulic fluid is pumped to apply pressure to one side (e.g., first chamber 972) of the piston 956. Therefore, the piston 956 can only move in one direction by the generation of the force. A return mechanism 952 (e.g., spring or gravity) is used to return the piston 956 from the second position to the first position. In other cases, the hydraulic cylinder 905 is double-acting. For example, hydraulic fluid is pumped to apply pressure to both sides (e.g., the first chamber 972 and a second chamber 980) of the piston 956. Hydraulic fluid creates pressure along the surface in the first chamber 972, generating a force to move the piston 956 between the first position and the second position. To move the piston 956 between the second position and the first position, hydraulic fluid creates pressure along the surface in the second chamber 980 to generate a force.

[0084] As mentioned previously, operation of the piston 956 may generate corresponding movement in the work head, which may move one or both of the cutting elements (e.g., blades, dies, etc.) in order to perform a work operation (e.g., a cut, knockout, etc.). Further, during operation of the tool 900, any of the processes described in FIGS. 4A-7B may be implemented to perform cutting element (e.g., blade, die, etc.) retraction and mitigate the risk of unwanted wear and tear on the tool 900. Further, it should be understood that the tool 900 may be a cutting tool, a crimping tool, a knockout tool, or any other form of hydraulic tool including a work head used to perform a work operation on a work piece (e.g., cable, sheet metal, etc.).

[0085] In some implementations, devices or systems disclosed herein can be utilized, manufactured, or installed using methods embodying aspects of the invention. Correspondingly, any description herein of particular features, capabilities, or intended purposes of a device or system is generally intended to include disclosure of a method of using such devices for the intended purposes, a method of otherwise implementing such capabilities, a method of manufacturing relevant components of such a device or system (or the device or system as a whole), and a method of installing disclosed (or otherwise known) components to support such purposes or capabilities. Similarly, unless otherwise indicated or limited, discussion herein of any method of manufacturing or using for a particular device or system, including installing the device or system, is intended to inherently include disclosure, as embodiments of the invention, of the utilized features and implemented capabilities of such device or system.

FURTHER EXAMPLES

[0086] Example 1. A knockout punch tool, comprising: a housing; a working head coupled to the housing and including a cutting die to perform a knockout operation on a workpiece; a hydraulic circuit including a hydraulic actuator to move the cutting die; a pump providing pressurized hydraulic fluid to the hydraulic circuit; a pressure sensor to measure pressure within the hydraulic circuit; a fluid reservoir; and a controller to: monitor pressure measurements from the pressure sensor during the knockout operation, determine that the knockout operation is complete when: the pressure measurements from the pressure sensor exceed a first threshold indicating a cutting operation has started; and the pressure measurements from the pressure sensor subsequently drop below a second threshold lower than the first threshold; determine when a pressure derivative based on the measured pressure is at or near zero; verify that the pressure derivative remains at or near zero for a preset amount of time; and automatically initiate a hydraulic dump sequence to release pressurized hydraulic fluid from the hydraulic circuit back to the fluid reservoir to retract the cutting die to a home position.

[0087] Example 2. The knockout punch tool of Example 1, wherein the preset amount of time is in a range of about 50 milliseconds to about 250 milliseconds.

[0088] Example 3. The knockout punch tool of Example 1 or Example 2, wherein the controller is further configured to: implement a buffer counter that increments when the pressure derivative is at or near zero and decrements when the pressure derivative moves outside a zero range.

[0089] Example 4. The knockout punch tool of Example 3, wherein the controller decrements the buffer counter at a higher rate than it increments the buffer counter.

[0090] Example 5. The knockout punch tool of any one of Examples 1 to 4, wherein the controller is further configured to: store a maximum cut pressure corresponding to a maximum pressure measured from initiation of the knockout operation until determination that the knockout operation is complete; and store a maximum cycle pressure corresponding to a maximum pressure measured during an operational cycle.

[0091] Example 6. The knockout punch tool of any one of Examples 1 to 5, further comprising: a trigger coupled to the housing; and the controller to initiate the knockout operation in response to actuation of the trigger.

[0092] Example 7. The knockout punch tool of any one of Examples 1 to 6, wherein the first threshold serves as a cut start threshold that distinguishes between initial system pressurization and higher pressures developed when the cutting die encounters resistance from the workpiece.

[0093] Example 8. A method of operating a knockout punch tool having a cutting die, a hydraulic circuit, and a pressure sensor, the method comprising: initiating a knockout operation by activating a pump to provide pressurized hydraulic fluid to the hydraulic circuit to move the cutting die; monitoring pressure measurements from the pressure sensor during the knockout operation; determining that a cutting operation has started when the pressure measurements exceed a first threshold; determining that a workpiece has been cut when the pressure measurements subsequently drop below a second threshold that is lower than the first threshold; monitoring a pressure derivative after determining that the workpiece has been cut; determining when the pressure derivative is at or near zero; verifying that the pressure derivative remains at or near zero for a preset amount of time using a buffer counter; and automatically initiating a hydraulic dump sequence to release pressurized hydraulic fluid from the hydraulic circuit back to a fluid reservoir to retract the cutting die to a home position after the verification is complete.

[0094] Example 9. The method of Example 8, wherein the preset amount of time is in a range of about 50 milliseconds to about 250 milliseconds.

[0095] Example 10. The method of Example 8 or Example 9, wherein the buffer counter increments when the pressure derivative is at or near zero and decrements when the pressure derivative moves outside a zero range.

[0096] Example 11. The method of Example 10, wherein the buffer counter decrements at a higher rate than it increments.

[0097] Example 12. The method of any one of Examples 8 to 11, further comprising: storing a maximum cut pressure corresponding to a maximum pressure measured from initiation of the knockout operation until determination that the knockout operation is complete.

[0098] Example 13. The method of Example 12, further comprising: storing a maximum cycle pressure corresponding to a maximum pressure measured during an operational cycle.

[0099] Example 14. The method of any one of Examples 8 to 13, wherein the first threshold serves as a cut start threshold that distinguishes between initial system pressurization and higher pressures developed when the cutting die encounters resistance from the workpiece.

[0100] Example 15. A knockout punch tool, comprising: a housing; a working head coupled to the housing and including a cutting die; a hydraulic actuator to move the cutting die during a knockout operation; a hydraulic circuit in fluid communication with the hydraulic actuator; a pressure sensor in communication with the hydraulic circuit; a controller configured to receive pressure measurements from the pressure sensor and determine completion of the knockout operation based on the pressure measurements; and an automatic blade retraction mechanism controlled by the controller and configured to automatically retract the cutting die to a home position upon determination that the knockout operation is complete, the controller causing the automatic blade retraction mechanism to initiate a hydraulic dump sequence that releases pressurized hydraulic fluid from the hydraulic circuit back to a fluid reservoir.

[0101] Example 16. The knockout punch tool of Example 15, wherein the controller is configured to determine completion of the knockout operation by: detecting when pressure measurements exceed a first threshold indicating a cutting operation has started and subsequently drop below a second threshold.

[0102] Example 17. The knockout punch tool of Example 16, wherein the controller is further configured to monitor a pressure derivative after the pressure measurements drop below the second threshold and determine when the pressure derivative is at or near zero.

[0103] Example 18. The knockout punch tool of Example 17, wherein the controller is configured to verify that the pressure derivative remains at or near zero for a preset amount of time before initiating the hydraulic dump sequence.

[0104] Example 19. The knockout punch tool of Example 18, wherein the controller implements a buffer counter that increments when the pressure derivative is at or near zero and decrements when the pressure derivative moves outside a zero range.

[0105] Example 20. The knockout punch tool of any one of Examples 15 to 19, wherein the controller is further configured to store a maximum cut pressure corresponding to a maximum pressure measured from initiation of the knockout operation until determination that the knockout operation is complete.

[0106] Also as used herein, unless otherwise limited or defined, or indicates a non-exclusive list of components or operations that can be present in any variety of combinations, rather than an exclusive list of components that can be present only as alternatives to each other. For example, a list of A, B, or C indicates options of: A; B; C; A and B; A and C; B and C; and A, B, and C. Correspondingly, the term or as used herein is intended to indicate exclusive alternatives only when preceded by terms of exclusivity, such as either, one of, only one of, or exactly one of. For example, a list of one of A, B, or C indicates options of: A, but not B and C; B, but not A and C; and C, but not A and B. A list preceded by one or more (and variations thereon) and including or to separate listed elements indicates options of one or more of any or all of the listed elements. For example, the phrases one or more of A, B, or C and at least one of A, B, or C indicate options of: one or more A; one or more B; one or more C; one or more A and one or more B; one or more B and one or more C; one or more A and one or more C; and one or more of A, one or more of B, and one or more of C. Similarly, a list preceded by a plurality of (and variations thereon) and including or to separate listed elements indicates options of multiple instances of any or all of the listed elements. For example, the phrases a plurality of A, B, or C and two or more of A, B, or C indicate options of: A and B; B and C; A and C; and A, B, and C.

[0107] As used herein, unless otherwise defined or limited, directional terms are used for convenience of reference for discussion of particular figures or examples. For example, references to downward (or other) directionsor top (or other) positionsmay be used to discuss aspects of a particular example or figure, but do not necessarily require similar orientation or geometry in all installations or configurations.

[0108] Also as used herein, unless otherwise limited or defined, substantially parallel indicates a direction that is within 12 degrees of a reference direction (e.g., within 6 degrees), inclusive.

[0109] Also as used herein, unless otherwise limited or defined, substantially perpendicular indicates a direction that is within 12 degrees of perpendicular a reference direction (e.g., within 6 degrees), inclusive.

[0110] Also as used herein, unless otherwise limited or defined, integral and derivatives thereof (e.g., integrally) describe elements that are manufactured as a single piece without fasteners, adhesive, or the like to secure separate components together. For example, an element stamped, cast, or otherwise molded as a single-piece component from a single piece of sheet metal or using a single mold, without rivets, screws, or adhesive to hold separately formed pieces together is an integral (and integrally formed) element. In contrast, an element formed from multiple pieces that are separately formed initially then later connected together, is not an integral (or integrally formed) element.

[0111] Additionally, unless otherwise specified or limited, the terms about and approximately, as used herein with respect to a reference value, refer to variations from the reference value of 15% or less, inclusive of the endpoints of the range. Similarly, the term substantially equal (and the like) as used herein with respect to a reference value refers to variations from the reference value of less than 10%, inclusive. Where specified, substantially can indicate in particular a variation in one numerical direction relative to a reference value. For example, substantially less than a reference value (and the like) indicates a value that is reduced from the reference value by 10% or more, and substantially more than a reference value (and the like) indicates a value that is increased from the reference value by 10% or more.

[0112] Also as used herein, unless otherwise limited or specified, substantially identical refers to two or more components or systems that are manufactured or used according to the same process and specification, with variation between the components or systems that are within the limitations of acceptable tolerances for the relevant process and specification. For example, two components can be considered to be substantially identical if the components are manufactured according to the same standardized manufacturing steps, with the same materials, and within the same acceptable dimensional tolerances (e.g., as specified for a particular process or product).

[0113] Unless otherwise specifically indicated, ordinal numbers are used herein for convenience of reference, based generally on the order in which particular components are presented in the relevant part of the disclosure. In this regard, for example, designations such as first, second, etc., generally indicate only the order in which a thus-labeled component is introduced for discussion and generally do not indicate or require a particular spatial, functional, temporal, or structural primacy or order.

[0114] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Given the benefit of this disclosure, various modifications to these embodiments will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.