Crane with rotary locking mechanism

Abstract

A telescoping crane boom having a rotary locking mechanism. A motor drives a rotating element about an axis parallel to the axis of the crane boom. The rotation of the rotating member causes a pin to selectively lock and unlock sections of the telescoping crane boom.

Claims

1. A telescoping boom, comprising: a base section having a base end and a telescoping end; a first telescoping section disposed within the base section, the first telescoping section having a recess configured to receive a cylinder-to-section pin; an inverted hydraulic actuator disposed within the base section, the inverted hydraulic actuator having a rod and a cylinder configured to extend and retract longitudinally relative to the base section; a rotating element coupled to the cylinder, the rotating element having an axis of rotation parallel to a longitudinal axis of the base section and the cylinder-to-section pin perpendicular to the axis of rotation, the rotating element having a first configuration in which the cylinder-to-section pin engages the first telescoping section and a second configuration angularly offset from the first configuration in which the cylinder-to-section pin does not engage the first telescoping section; and a motor coupled to the base section and the rotating element, the motor configured to rotate the rotating element and the cylinder-to-section pin relative to the base section.

2. The telescoping boom of claim 1, wherein the recess has a ramped engagement in a longitudinal direction.

3. The telescoping boom of claim 1, further comprising a plurality of proximity sensors disposed in the base section, the plurality of proximity sensors configured to identify a boom section.

4. The telescoping boom of claim 1, further comprising a second telescoping section disposed within the first telescoping section.

5. A crane comprising: a chassis; an upper works coupled to the chassis, the upper works comprising the telescoping boom of claim 1.

6. The crane of claim 5, wherein the recess has a ramped engagement in a longitudinal direction.

7. The crane of claim 5, wherein the telescoping boom further comprises a plurality of proximity sensors disposed in the base section, the plurality of proximity sensors configured to identify a boom section.

8. The crane of claim 5, wherein the telescoping boom further comprises a second telescoping boom section disposed within the first telescoping boom section.

9. A rotary locking mechanism for a crane boom, comprising: a rotating element having a bearing surface configured to interact with an inverted hydraulic cylinder; a motor configured to drive the rotating element about an axis of rotation; and at least one cylinder-to-section pin having a first configuration corresponding to the rotating element being in a first angular orientation and a second configuration corresponding to the rotating element being in a second angular orientation wherein the at least one cylinder-to-section pin is configured to rotate from the first configuration to the second configuration.

10. The rotary locking mechanism of claim 9, wherein a body of the motor is fixed relative to the bearing surface of the rotating element.

11. The rotary locking mechanism of claim 9, wherein a body of the motor is fixed relative to the at least one cylinder-to-section pin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates an overview of an existing mobile crane.

(2) FIG. 2 illustrates a detailed view of the tip of a boom of a mobile crane showing the nested boom sections.

(3) FIG. 3 illustrates a schematic of an actuator.

(4) FIG. 4 illustrates an embodiment of a rotary locking mechanism.

(5) FIG. 5 illustrates the embodiment of FIG. 4 with the pin in a locked position.

(6) FIG. 6 illustrates an embodiment of a rotary locking mechanism.

(7) FIG. 7 illustrates the embodiment of FIG. 6 with a retracted pin.

(8) FIG. 8 illustrates a system of proximity switches for determining a boom segment.

DETAILED DESCRIPTION

(9) The present embodiments will now be further described. In the following passages, different aspects of the embodiments are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

(10) FIG. 4 illustrates an embodiment of a rotating locking mechanism 42 for coupling an inverted hydraulic actuator 26 to a telescoping boom section. For simplicity, the rotating locking mechanism 42 is shown without the base boom section 16, the telescoping boom sections 18, 20, 22, 24, and the rod 28 of the inverted hydraulic actuator 26. In operation, the rotating locking mechanism 42 would be disposed internal to the base main boom section 16 with the rod 28 of the inverted hydraulic actuator 26 extending through the rotating locking mechanism 42.

(11) The rotating locking mechanism 42 includes a motor 44 for providing a rotary motion and a rotating element 46. The motor 44 may be an electrical motor, a pneumatic motor, or a hydraulic motor. In conventional booms, electrical power may already be provided by way of a cable reel mechanism that is a part of the conventional pinned boom design (for electrical power for solenoids in valves and electrical communications). Similarly, pneumatic power might also be provided by a reel. Pneumatic power is advantageous in that it is able to store energy over a period of time (building pressure), and then being released in a sudden demand for power.

(12) In FIG. 4, the conventional pinning head 32, has been removed and replaced with the rotating locking mechanism 42. The motor 44 is rigidly mounted to the inverted hydraulic actuator 26 to prevent its body 54 from rotating relative to the inverted hydraulic actuator 26. The driveshaft of the motor drives the rotating element 46 through a circular rack 48 and pinion 50 gear combination. Other techniques for transmitting torque between the motor 44 and the rotating element 46 are contemplated such as a chain drive, pulley system, or compound gears. In some embodiments, it is possible to reverse the elements, such that the motor 44 is mounted to the rotating element 46 and rotates with the element while the circular rack 48 remains stationary.

(13) The rotating element 46 has a cylinder-to-section pin 52 that extends from an outer surface 56 of the rotating element 46. The rotating element 46 may have protrusions 58 on the outer surface 56 of the rotating element that interact with proximity switches 60 on a non-rotating portion of the rotating locking mechanism 42 to detect the relative position of the rotating element 46. The proximity switches 60 may be used to determine the two extents of the rotating element 46. The rotating element 46 may have a bearing surface 66 such as a roller bearing for the interface between the rotating element 46 and the inverted hydraulic actuator 26. Other embodiments may use a journal bearing or a thrust bearing between the rotating element 46 and the inverted hydraulic actuator 26.

(14) The cylinder-to-boom section pin 52 transmits an axial force from the inverted hydraulic actuator 26 to a telescoping boom section through the rotating mechanism 46 to extend the boom 12. In some embodiments, there is no de-rating for the inverted hydraulic actuator 26 as the boom 12 is extended or retracted, such that the interface between the telescoping boom section and the inverted hydraulic actuator 26 transmits the full load of the boom 12 during telescoping operations.

(15) FIG. 5 illustrates the rotating locking mechanism 42 of FIG. 4 along with a partial view of a telescoping boom section. In this view, the rotating locking mechanism 42 is shown engaged in a locked position with the cylinder-to-section pin 52 engaged with a the telescoping boom section. The telescoping boom section has a recess 62 that receives the cylinder-to-boom section pin 52. The recess 62 has a ramped engagement region 64 that guides the cylinder-to-boom section pin 52 into position. The rotating locking mechanism 42 is able to pin the inverted hydraulic actuator 26 to the telescoping boom section if the cylinder-to-boom section pin 52 encounters the recess 62 at either the ramped engagement region 64, or the recess 62 itself. In some embodiments, if the cylinder-to-boom section pin 52 encounters the ramped engagement region 64, the cylinder-to-boom section pin may push either the inverted hydraulic actuator 26 or the telescoping boom section axially to align the cylinder-to-boom pin and the recess.

(16) In operation, once the rotating locking mechanism is in the general location of engagement, the motor 44 may attempt to rotate the rotating element 46 and consequently the cylinder-to-boom section pin 52 into the engagement with the recess 62. If the cylinder-to-boom section pin 52 and the recess 62 are not aligned, the inverted hydraulic actuator 26 may be extended or retracted to assist engagement. In embodiments using a pneumatic drive, the motor 22 may be powered even if the cylinder-to-boom section pin 52 is not in position to engage the recess 62. Then, once the cylinder-to-boom section pin 52 encounters the recess 62 as the inverted hydraulic actuator 26 is moved axially, the air motor would move the cylinder-to-boom section pin 52 pin into the recess 62.

(17) In some embodiments, the motor 44 may have a rotational encoder to indicate which telescoping boom section the cylinder-to-boom section pin 52 is engaging with. For example, each telescoping boom section may have a different angular orientation of the recess 62 such that a bottom of each recess 62 has different angular orientation. By measuring the angular orientation at which the cylinder-to-boom section pin 52 encounters the bottom of the recess 62, it is possible to identify the telescoping boom section being actuated.

(18) In some embodiments, rather than position the rotating locking mechanism 42 at the recess 62 and then rotating the cylinder-to-boom section pin 52 into engagement with the recess 62, the rotating locking mechanism 42 may be positioned to a known position offset from the recess 62. The motor 44 may then be powered at the same time as the inverted hydraulic actuator 26. As the recess 62 comes into position, the rotatory locking mechanism moves the cylinder-to-boom section pin 52 into the locked position.

(19) FIG. 6 illustrates another embodiment of a rotary locking mechanism 70. In this embodiment, a rotating element 72 has at least one slot 74 having a first end 76 towards the axis of rotation of the rotating element 72 and a second end 78 positioned away from the axis of rotation. A cylinder-to-boom section pin 80 is disposed on a side of the rotary locking mechanism 70 and is able to move laterally to engage and disengage telescoping boom sections. The rotary locking mechanism 70 has a recess 82 parallel to the axis of the inverted hydraulic actuator 26 that aligns with the cylinder-to-boom section pin 80 and the slot 74 in the rotating element 72. A pin actuator 84 resides in the recess 82 and connects the cylinder-to-boom section pin 80 to the slot 74 of the rotating element 72. When the motor 86 is powered, it causes the rotating element 72 to turn and the slot 74 forces the pin actuator 84 to move laterally, as shown in FIG. 7. The lateral movement of the pin actuator 84 causes the cylinder-to-boom section pin 80 to move laterally, locking boom sections to the inverted hydraulic actuator 26.

(20) In some embodiments, it may be beneficial to improve the system for aligning the inverted hydraulic actuator 26 with the telescoping boom sections. It would be beneficial for the new system to indicate general alignment and identify which boom section has been approached. This information is valuable for the control system and removes some of the need to store a history of which operations have been performed to determine the current state of the boom.

(21) FIG. 8 illustrates an embodiment of a rotary locking mechanism 42 having a positive boom section identification system. The rotating locking mechanism 42 includes an array of proximity switches 88 and the boom sections include section identifying targets 90. The section identification targets 90 are offset laterally and allow unique identification of the boom sections. A pattern of three proximity switches 88 and corresponding targets 90 can uniquely identify up to seven boom sections (patterns such as 0-0-1, 0-1-0, 0-1-1, 1-0-0, 1-0-1, 1-1-0, and 1-1-1). The identification targets 90 can also perform a dual function in indicating both the boom section, and the engagement area for the rotary locking mechanism 42 to actuate the cylinder-to-boom section pin.

(22) It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.