Reversion trigger for combustion-powered fastener-driving tool

Abstract

A fastener-driving tool has a housing including a combustion chamber, where the combustion chamber generates combustion for driving a fastener, and a processor associated with the housing and in communication with the combustion chamber. The processor is configured to cause an initial combustion in the combustion chamber and cause a fastener to be driven when a first actuation event and a second actuation event occur, and is configured to cause at least one subsequent combustion in the combustion chamber and cause at least one additional fastener to be driven when only the first actuation event occurs.

Claims

1. A fastener-driving tool comprising: a housing; a combustion chamber in the housing; a workpiece contact element movably connected to the housing and movable from a rest position to an activated position; a trigger movably connected to the housing, the trigger movable from a rest position to an activated position; and an actuation lever movably connected to the trigger; wherein in a sequential actuation mode, combustion is generated in the combustion chamber to drive a fastener into a workpiece each time the workpiece contact element and the trigger are each moved from the respective rest position to the respective activated position in a designated sequence, wherein in the sequential actuation mode, responsive to the trigger remaining in the activated position after driving the fastener into the workpiece, a chamber lockout device is activated to switch the fastener-driving tool from the sequential actuation mode to a contact actuation mode, and wherein in the contact actuation mode, the trigger remains in the activated position and combustion is generated in the combustion chamber to drive at least one additional fastener into the workpiece each time the workpiece contact element is moved to the activated position by depressing the workpiece contact element on the workpiece.

2. The tool of claim 1, wherein the actuation lever includes a bias member configured to bias the actuation lever.

3. The tool of claim 1, which includes a sleeve associated with the workpiece contact element, the sleeve configured to move from a closed position wherein the sleeve closes the combustion chamber to an open position wherein the sleeve does not close the combustion chamber.

4. The tool of claim 3, wherein the chamber lockout device is configured to temporarily hold the sleeve in the closed position for a designated period of time.

5. The tool of claim 4, wherein the designated period of time is 100 msec.

6. A fastener-driving tool comprising: a housing; a combustion chamber in the housing; a workpiece contact element movably connected to the housing and movable from a rest position to an activated position; a trigger movably connected to the housing, the trigger movable from a rest position to an activated position; an actuation lever movably connected to the trigger, the actuation lever including a bias member configured to bias the actuation lever; a sleeve associated with the workpiece contact element, the sleeve configured to move from a closed position wherein the sleeve closes the combustion chamber to an open position wherein the sleeve does not close the combustion chamber; and a chamber lockout device configured to temporarily hold the sleeve in the closed position for a designated period of time, wherein in a sequential actuation mode, combustion is generated in the combustion chamber to drive a fastener into a workpiece each time the workpiece contact element and the trigger are each moved from the respective rest position to the respective activated position in a designated sequence, wherein in the sequential actuation mode, responsive to the trigger remaining in the activated position after driving the fastener into the workpiece, the chamber lockout device is activated to switch the fastener-driving tool from the sequential actuation mode to a contact actuation mode, and wherein in the contact actuation mode, the trigger remains in the activated position and combustion is generated in the combustion chamber to drive at least one additional fastener into the workpiece each time the workpiece contact element is moved to the activated position by depressing the workpiece contact element on the workpiece.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a front perspective view of a conventional fastener-driving tool;

(2) FIG. 2 is a fragmentary vertical cross-section of the tool of FIG. 1 shown in the rest position;

(3) FIG. 3 is a cross-sectional view of a trigger control mechanism for a combustion-powered fastener-driving tool that includes a trigger assembly having an actuation lever where the trigger assembly and the workpiece contact element are in a rest position;

(4) FIG. 4 is a cross-sectional view of the fastener-driving tool of FIG. 3 showing the chamber lockout device in a non-activated position;

(5) FIG. 5 is a cross-sectional view of the fastener-driving tool of FIG. 3 in the sequential actuation mode, where the workpiece contact element is depressed against a workpiece, the actuation lever has moved to a position adjacent to the trigger assembly and the trigger has been depressed to drive a fastener into the workpiece;

(6) FIG. 6 is a cross-sectional view of the fastener-driving tool of FIG. 3 showing the chamber lockout device in the activated or lockout position;

(7) FIG. 7 is a cross-sectional view of the fastener-driving tool of FIG. 3 between actuations of the tool in the contact actuation mode, where the workpiece contact element has been removed from the workpiece causing the actuation lever to disengage from the actuation pin;

(8) FIG. 8 is a cross-sectional view of the fastener-driving tool of FIG. 3, where the workpiece contact element is depressed against the workpiece and the trigger has been released thereby resetting the tool from the contact actuation mode to the sequential actuation mode.

DETAILED DESCRIPTION

(9) Referring now to FIGS. 1-2, a combustion-powered fastener-driving tool is generally designated 10 and is of the general type described in detail in the patents listed above and incorporated by reference in the present application. A housing 12 of the tool 10 encloses a self-contained internal power source 14 (FIG. 2) within a housing main chamber 16. As is generally known in the art, the power source 14 is powered by internal combustion and includes a combustion chamber 18 that communicates with a cylinder 20. A piston 22 reciprocally disposed within the cylinder 20 is connected to the upper end of a driver blade 24. As shown in FIG. 2, an upper limit of the reciprocal travel of the piston 22 is referred to as a pre-firing or pre-actuating position, which occurs just prior to firing or actuation of the tool, or the ignition of the combustion gases which initiates the downward driving of the driver blade 24 to impact a fastener (not shown) to drive it into a workpiece.

(10) Through depression of a trigger 26, an operator induces combustion within the combustion chamber 18, causing the driver blade 24 to be forcefully driven downward through a nosepiece 28 (FIG. 1). The nosepiece 28 guides the driver blade 24 to strike a fastener that had been delivered into the nosepiece via a fastener magazine 30.

(11) Included in the nosepiece 28 is a workpiece contact element 32, which is connected, through a linkage or upper probe 34 to a reciprocating valve sleeve 36, an upper end of which partially defines the combustion chamber 18. Depression of the tool housing 12 against the workpiece contact element 32 in a downward direction as seen in FIG. 1 (other operational orientations are contemplated as are known in the art), causes the workpiece contact element to move from a rest position to a firing or actuation position. This movement overcomes the normally downward biased orientation of the workpiece contact element 32 caused by a spring 38 (shown hidden in FIG. 1). It is contemplated that the location of the spring 38 may vary to suit the application, and locations displaced farther from the nosepiece 28 are envisioned.

(12) Through the linkage 34, the workpiece contact element 32 is connected to and reciprocally moves with, the valve sleeve 36. In the rest position (FIG. 2), the combustion chamber 18 is not sealed, since there is an annular gap 40 separating the valve sleeve 36 and a cylinder head 42, which accommodates a chamber switch 44 and a spark plug 46. Specifically, there is an upper gap 40U near the cylinder head 42, and a lower gap 40L near the upper end of the cylinder 20. In the preferred embodiment of the present tool 10, the cylinder head 42 also is the mounting point for a cooling fan 48 and a fan motor 49 powering the cooling fan. The fan and at least a portion of the motor extend into the combustion chamber 18 as is known in the art and described in the patents which have been incorporated by reference above. In the rest position depicted in FIG. 2, the tool 10 is disabled from firing because the combustion chamber 18 is not sealed at the top with the cylinder head 42, and the chamber switch 44 is open.

(13) Actuation or firing is enabled when an operator presses the workpiece contact element 32 against a workpiece. This action overcomes the biasing force of the spring 38, causes the valve sleeve 36 to move upward relative to the housing 12, closing the gaps 40U and 40L and sealing the combustion chamber 18 until the chamber switch 44 is activated. This operation also induces a measured amount of fuel to be released into the combustion chamber 18 from a fuel canister 50 (shown in fragment).

(14) Upon a pulling of the trigger 26, the spark plug 46 is energized and produces a spark that ignites the fuel and air mixture in the combustion chamber 18 and propels the piston 22 and the driver blade 24 downward through the cylinder and toward the waiting fastener for entry into the workpiece. As the piston 22 travels down the cylinder, it pushes a rush of air which is exhausted through at least one petal or check valve 52 and at least one vent hole 53 located beyond piston displacement (FIG. 2). At the bottom of the piston stroke or the maximum piston travel distance, the piston 22 impacts a resilient bumper 54 as is known in the art. With the piston 22 beyond the exhaust check valve 52, high pressure gasses vent from the cylinder 20 until near atmospheric pressure conditions are obtained and the check valve 52 closes. Due to internal pressure differentials in the cylinder 20, the piston 22 is returned to the pre-actuation position shown in FIG. 2. Because conventional combustion-powered fastener-driving tools typically only operate in a sequential actuation mode, the above process must be repeated to drive another fastener into the workpiece.

(15) Referring now to FIGS. 3-8, an example combustion-powered nailer 100 includes a trigger control mechanism that enables the nailer to operate in both a sequential actuation mode and a contact actuation mode.

(16) The trigger control mechanism or trigger control assembly, generally indicated by reference number 102, is configured to be mounted upon a housing 104. A workpiece contact element assembly 106 includes a workpiece contact element 108, which is configured to be depressed on contact with a workpiece 101, and a workpiece contact element linkage 110, which is slidably mounted in a reciprocal manner upon the fastener-driving tool housing 104.

(17) A trigger switch assembly 114 is mounted to the housing 104 so as to initiate either a sequential or a contact actuation operational mode of the fastener-driving tool 100 when the trigger switch assembly is actuated by the trigger control mechanism 102 of the present disclosure as will be described below. More particularly, the trigger switch assembly 114 includes a switch housing 116 biased by a spring 118 and configured to be seated upon a switch seat 120, and a stem 122 configured to be engaged by an actuation lever 124 of the trigger control mechanism 102. The actuation lever 124 is movably connected to a trigger 126 by a pin 128 and is movable between a first position or rest position (FIG. 3) and a second position or activated position (FIG. 5). A bias member, such as spring 130 connected to the pin 128, biases the actuation lever 124 to the rest position.

(18) The operation of the structural components in the sequential actuation mode and the contact actuation mode will now be described.

(19) Referring to FIG. 3-5, in the sequential operation mode, the workpiece contact element 108 of the combustion nailer 100 is pressed against a workpiece 101, which is a first actuation event, causing the workpiece contact element and the linkage 110 attached of the workpiece contact element assembly 106 to move upwardly within the housing 104. The linkage 110, which is connected with or integrally formed with the valve sleeve 132, reciprocally moves the sleeve upwardly and closes the combustion chamber 134, which also activates a head switch (not shown) adjacent to the chamber. The linkage 110 also contacts the actuation lever 124 causing the actuation lever 24 to move from a rest position to an activated position as shown in FIG. 5. In a second actuation event, a user presses the trigger 126 inwardly, i.e., activates the trigger, which in turn, depresses the stem 122 inwardly to activate it. After both the head switch and the stem 122 are activated, a spark is initiated to ignite the fuel mixture in the combustion chamber 134 thereby generating combustion. The combustion explosion within the chamber 134 drives piston 136 and driver blade 138 through cylinder 139 and into contact with a fastener 140 located in drive channel 141 to drive the fastener into a workpiece 101.

(20) The user may now remove the tool from the workpiece 101 and repeat the above steps to continue in the sequential operational mode. Alternatively, to initiate the contact actuation mode (also referred to herein as the bump actuation mode), the user keeps the trigger 126 depressed or in the activated position. Upon this action, a processor 137 (FIG. 3) to activate a chamber lockout device 142 (FIG. 4), such as the lockout device described in commonly owned U.S. Pat. No. 7,383,974 and U.S. application Ser. No. 13/469,795, which are both herein incorporated by reference in their entireties. It should be appreciated that the lockout device 142 may be any suitable lockout device. In the illustrated embodiment, the lockout device 142 includes a pivot arm 144 that pivots between a lockout position (FIG. 6) where the pivot arm contacts and holds the valve sleeve 132 in the closed position so that the combustion chamber 134 remains closed, and a released position (FIG. 4) where the pivot arm is dis-engaged from the sleeve 132 so that the sleeve 132 may move to the open position.

(21) Referring now to FIGS. 6-9, upon activation of the lockout device 142, the pivot arm 142 moves from the released position to the lockout position (FIG. 6). In the lockout position, an end of the pivot arm 142 engages and temporarily holds the sleeve 132 in the closed position and thereby keeps the combustion chamber 134 in the closed position to allow time for the piston to reach the top position in the cylinder. As discussed below, the processor is programmed to activate the lockout device for a designated period of time that is equal to or greater than the time needed for the piston to return to the top position of the cylinder. In the contact actuation mode, the processor bypasses the head switch so that the sequential sequence of first activating the head switch and then depressing the trigger 126 is not required to further actuate the combustion nailer 100 and drive fasteners 140 into the workpiece 101. Thus, in the contact actuation mode, the nailer 100 can be moved from one location to another location relative to the workpiece 101 without needing to repeat the actuation sequence discussed above.

(22) When the nailer 100, and more specifically, the workpiece contact element 108, is removed from the workpiece 101 and the lockout device has been de-activated and disengaged from the sleeve, the workpiece contact element moves from the depressed or activated position to the non-depressed or rest position shown in FIG. 7. The nailer 100 is then moved, if needed, to a different location on the workpiece 101 and pressed against the workpiece. As described above, when the workpiece contact element 108 is pressed against the workpiece 101, the workpiece contact element 108 and the associated linkage 110 moves upwardly. When the linkage 110 moves upwardly, it contacts the actuation lever 124 and pushes the actuation lever to the activated position (FIG. 8) where it contacts and presses the stem 122 inwardly to initiate the combustion sequence described above. The combustion generated in the combustion chamber 134 causes the piston 136 and driver blade 138 to be driven through the cylinder to drive a fastener 140 into the workpiece 101.

(23) As described above, the processor is programmed with a preset or designated lockout time period so that the lockout device 142 remains activated for the designated period of time to lock the valve sleeve 132 in position and keep the combustion chamber 134 closed. In an embodiment, the lockout device is activated for 100 msec in each actuation of the tool. It should be appreciated that the lockout time period may be any suitable amount of time.

(24) The combustion nailer 100 remains in the bump actuation mode until a reset event occurs. Upon an occurrence of a reset event, the nailer 100 is reset to operate in the sequential operation mode. For example, a reset event may occur when the trigger 126 is released (FIG. 8) or when a fastener 140 has not been driven into the workpiece 101 (i.e., the tool has been inactive) for a designated amount of time, i.e., the reset time period. The processor is programmed with the reset time period where the reset time period may be any suitable amount of time. A user must now press the workpiece contact element 110 against the workpiece 101 or another workpiece and press the trigger 126 in this sequence to initiate the sequential actuation mode or the bump actuation mode.

(25) The combination of the present trigger assembly 102 and the lockout device 142 enables the combustion nailer 100 to be operated in both a sequential activation mode and a bump actuation mode. Such flexibility in operation of the nailer 100 enables users to be able to easily switch from a sequential operation mode to a bump actuation mode at a job site without having to switch tools thereby saving significant time and cost.

(26) While a particular embodiment of a combustion-powered fastener-driving tool has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.