CYLINDER RETENTION DEVICE

Abstract

A system and method for retaining a linear actuator on a crane component such as a mast is disclosed. In the system a retaining mechanism is mounted on either a body of the linear actuator or the crane component and a catch is mounted to the other of the body or the crane component. Retraction of a rod of the linear actuator causes a cap on the rod to contact the retaining mechanism, which causes the retaining mechanism to move into a latched configuration securing the linear actuator.

Claims

1. A method for retaining an assist hydraulic cylinder coupled to a live mast, the method comprising: positioning the live mast having an assist hydraulic cylinder to have a minimum angle greater than sixty degrees relative to the horizon, with a rod extended from the hydraulic cylinder; retracting the rod until a rod end contacts a latching mechanism; and further retracting the rod end causing the latching mechanism to engage with a catch coupled to the live mast.

2. The method of claim 1, wherein causing the latching mechanism to engage with the catch comprises moving a pin parallel to the cylinder to position the catch between a portion of the pin and a portion of the cylinder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 illustrates a side view of an embodiment of a mobile lift crane having a live mast.

[0023] FIG. 2 illustrates a mobile lift crane assembling a crawler track to a car body.

[0024] FIG. 3 illustrates a mobile lift crane utilizing a linear actuator for assistance in setting up a boom.

[0025] FIG. 4 illustrates a schematic of a live mast on a mobile crane illustrating its various operating angles.

[0026] FIG. 5 illustrates an embodiment of a linear actuator and a live mast.

[0027] FIG. 6 illustrates the linear actuator of FIG. 5 being retained on the live mast.

[0028] FIG. 7 illustrates an embodiment of a linear actuator in an unlatched state.

[0029] FIG. 8 illustrates the embodiment of FIG. 7 in a latched state.

[0030] FIG. 9 illustrates the embodiment of FIG. 7 in a latched state.

[0031] FIG. 10 illustrates another embodiment of a linear actuator and a rotary retaining mechanism.

[0032] FIG. 11 illustrates another embodiment of a linear actuator and a retaining mechanism.

DETAILED DESCRIPTION

[0033] In the following passages, different 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.

[0034] While the disclosed subject matter (or various disclosed embodiments) will have applicability to many types of cranes, it (they) will be described in connection with a mobile lift crane 10, shown in an operational configuration with a live mast in FIG. 1. The mobile lift crane 10 includes lower works, also referred to as a car body 12, and moveable ground engaging members in the form of crawlers 14. Of course additional crawlers than those shown can be used, as well as other types of ground engaging members, such as tires.

[0035] A rotating bed 20 is mounted to the car body 12 with a slewing ring, such that the rotating bed 20 can swing about an axis with respect to the ground engaging members 14. The rotating bed 20 supports a boom 22 pivotally mounted on a front portion of the rotating bed 20; a live mast 28 mounted at its first end on the rotating bed 20, boom hoist rigging 30 connected to the live mast 28 adjacent a second end of the live mast 28; and a moveable counterweight unit 34. In FIG. 1, the counterweight unit 34 has multiple stacks of individual counterweight members on a support member. In other embodiments, the counterweight unit may have a single counter weight.

[0036] Boom hoist rigging 30 between the top of the live mast 28 and the rotating bed is used to control the angle of the live mast 28. A suspension assembly 37 between the top of the live mast 28 and the boom 22 supports the boom. A load hoist line (not shown) is trained over a pulley on the boom 22, supporting a hook (not shown) at a first end. At a second end, the load hoist line is wound on a first main load hoist drum (not shown) connected to the rotating bed 20. The rotating bed 20 includes other elements commonly found on a mobile lift crane 10, such as an operator's cab and a hoist drum for the boom hoist rigging 30.

[0037] The boom hoist rigging 30 includes a boom hoist line in the form of wire rope wound on a boom hoist drum, and reeved through sheaves on the live mast 28. The live mast 28 is connected to the rotating bed 20 though the boom hoist rigging 30 and to the boom through the suspension assembly 37. This arrangement allows rotation of the boom hoist drum to change the amount of boom hoist line between the live mast 28 and the rotating bed 20 changing the mast angle and thereby changing the boom angle through the suspension assembly 37.

[0038] FIG. 2 illustrates a partially assembled mobile crane 10 utilizing it's live mast 28 as a boom with a hydraulic cylinder 36 as a lifting component. The mobile lift crane of FIG. 2 has a single crawler 14 attached to the car body 12. The live mast and the hydraulic cylinder are being used to lift a second crawler to position it for installation on the car body.

[0039] FIG. 3 illustrates a partially assembled mobile crane 10 utilizing its live mast as a boom with the hydraulic cylinder as a lifting component for set up of a boom. The hydraulic cylinder is coupled to the boom and lifts it into position for attachment to the upper works of the mobile lift crane. Once assembled, the cylinder should be stowed/secured so that it does not interfere with normal operation of the boom.

[0040] FIG. 4 illustrates a live mast 28 having a linear actuator in the form of hydraulic cylinder 36. The live mast 28 is shown in six positions ranging from 0 degrees to 160 degrees relative to the rear horizontal as shown. The hydraulic cylinder 36 is typically mounted pivotably, near the top of the live mast (more or less about the centerline of sheaves 38) and is positioned by gravity as the live mast 28 is moved through its working range. Between the angles of 0 to 90 degrees, the hydraulic cylinder 36 rests against the live mast 28 due to gravity and it is only when the live mast 28 reaches 90 degrees that the hydraulic cylinder 36 swings free from the live mast 28 and may be used in assembly of the mobile crane 10.

[0041] FIG. 5 illustrates an embodiment of a linear actuator 50 having a retaining mechanism 52 for retaining the linear actuator 52 on a crane component 54. The linear actuator 50 of FIG. 5 includes a body 56, a rod 58, a pin holder 60, a pin 62, and an arm 64. FIG. 6 illustrates the linear actuator 50 of FIG. 5 with the rod 58 retracted, causing the retaining mechanism 52 to retain the linear actuator 50.

[0042] The body 56 has a first end 57 that mounts to a crane component, 54 such as live mast 28 in a rotating connection, as shown in FIG. 4. One example of a rotating connection is a pinned connection, as commonly used by those of ordinary skill in the art. The rotating connection rotates in an axis that is perpendicular to a longitudinal axis of the body 56.

[0043] The rod 58 extends from a second end 66 of the body 56 opposite the first end of the body 56. The rod 58 has a first portion 59 slidably disposed within the body 56 and a second portion 68 that extends from second end 66 of the body 56. The second portion 68 of the rod 58 has a cap 70, which may be coupled to a second crane component to effectuate movement of the second crane component relative to a crane component secured to the first end of the body 56. The cap 70 has a lateral extent that is greater than a lateral extent of the rod 58. In one embodiment, the rod 58 is circular in cross section, and the cap 70 is circular in cross section, and a radius of the cap 70 is greater than a radius of the rod 58. In another embodiment, the rod 58 has a circular cross section and the cap 70 has square cross section. In such an embodiment, a side of square cross section has a length greater than a diameter of the rod 58.

[0044] The pin holder 60 is coupled to the body 56 near the second end 66 of the body 56. The pin holder 60 holds a pin 62 slidably disposed in the pin holder 60 such that it may be moved in a longitudinal direction parallel to the rod 58. The pin 62 is biased to a position in which a portion of the pin 62 extends beyond the second end 66 of the body 56. The bias is provided by a spring 74 in the embodiment of FIGS. 5 and 6, but in other embodiments the bias may be provided by gravity or other means. The arm 64 extends laterally from the pin 62 to a lateral location between the lateral extent of the rod 58 and the lateral extent of the cap 70. As shown in FIG. 6, movement of the cap towards the body contacts the arm moving the pin against the bias and where the bias comprises a spring 74, compressing the spring.

[0045] FIG. 6 illustrates the linear actuator 50 with the pin 62 being moved against the bias by contact with the cap 70. The pin 62 extends from the pin holder 60 on an end opposite the arm 64, and extends into a catch 72 on the crane component 54, retaining the body 56 from moving away from the component.

[0046] FIG. 7 illustrates a detailed view of a mast assembly 100 having a mast 28, a hydraulic actuator 104, and a retaining mechanism 106. The entire mast 28 is illustrated in FIG. 2 and FIG. 3, while FIGS. 7, 8, and 9 illustrate a detailed view of the mast 28 interacting with a retaining mechanism 106. FIG. 7 illustrates the retaining mechanism 106 in an unactuated state, while FIG. 8 and FIG. 9 illustrate the retaining mechanism 106 in an actuated state.

[0047] The mast 28 has a base with a rotating connector for connection to the upper works of the mobile crane. Opposite the base is the top of the mast 28 and a catch 108 is positioned between the base and the top. The hydraulic actuator 104 has a cylinder 110 in a rotatable connection to the mast 28, a rod 112 extending from the cylinder 110, and a cap 114 coupled to the rod 112. The cap 114 has a lateral extent greater than a lateral extent of the rod 112. The retaining mechanism 106 is coupled to the cylinder 110 and includes a portion 116 positioned along the rod 112 between the lateral extent of the rod 112 and the lateral extent of the cap 114. A second portion 118 of the retaining mechanism is configured to latch with the catch 108 on the mast 28. The retaining mechanism 106 has a first configuration, shown in FIG. 7 in which the rod 112 is extended from the cylinder 110 and the cap 114 not does not engage the first portion 116 of the retaining mechanism 106. In a second configuration, shown in FIG. 8 and FIG. 9, the rod 112 is retracted and the cap 114 engages the first portion 116 of the retaining mechanism 106 moving the retaining mechanism 106 from the non-latching configuration of FIG. 7 to the latching configuration of FIG. 8 and FIG. 9. The retaining mechanism 106 is biased to the non-latching configuration, such that absent contact with the cap 114, the retaining mechanism 106 is in the non-latching configuration.

[0048] The first portion 116 of the retaining mechanism 106 may include an arm 119 that extends laterally from the second portion 118. The second portion 118 may be in the form of a pin 120. The pin 120 is slidably coupled to the cylinder 110 and has an axis parallel to an axis of the cylinder 110. The arm 118 may include a wear pad 122 in contact with the rod 112 made from a low friction, durable material such as nylon.

[0049] The catch 108 in the embodiment of FIGS. 7-9 is a lateral plate, but other catches are possible such as a slot or bar.

[0050] FIG. 10 illustrates an embodiment of latching mechanism 200 that uses a rotary motion for moving between a latched configuration and an unlatched configuration. Contact between the cap 202 and an arm 204 causes the latching mechanism 200 to rotate positioning a second portion 206 of the latching mechanism 200 under a latch 208 on the mast 210. When the cap 202 is extended as shown, a self-bias of the retaining mechanism 204 causes the retaining mechanism 200 to rotate the second portion 206 away from the latch 208, thereby unlatching the retaining mechanism 200.

[0051] FIG. 11 illustrates an embodiment of a mast assembly 300 with a retaining mechanism 302 coupled to a mast 304, rather than to a cylinder 306 as described previously. A hydraulic actuator 308 includes a cylinder 306 rotatably coupled to the mast 304, a catch 310 coupled to the cylinder 306, a rod 312 extending from the cylinder 306, and a cap 314 coupled to the rod 312. The retaining mechanism 302 is coupled to the mast 304 and includes a first portion 316 extending away from the mast 304 and a second portion 318 configured to latch with the catch 310. The retaining mechanism 318 has a non-latching configuration with the rod 312 extended and the cap 314 not engaging the first portion 316, and a latching configuration with the rod 312 retracted and engaging the first portion 316.

[0052] Embodiments of the disclosed subject matter are further directed to a method for retaining a hydraulic to a mast. In the method a live mast having an assist hydraulic cylinder is positioned to have a minimum angle less than ninety degrees relative to the horizon and with a rod extended from the hydraulic cylinder. The rod is then retracted until a rod end contacts a latching mechanism. The rod is then further retracting causing the latching mechanism to engage with a catch coupled to the live mast. In some embodiments, causing the latching mechanism to engage with a catch includes moving a pin parallel to the cylinder to position the catch between a portion of the pin and a portion of the cylinder.

[0053] 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. For example, instead of a single pin being used multiple pins may be used to engage the catch in multiple locations. A single arm could actuate the multiple pins, or in some embodiments each could have their own extending towards the rod. Additionally, while not described in detail, one of ordinary skill in the art will recognize that the different embodiments may be used in combination with one another. For example, the rotary mechanism of FIG. 10 may be utilized as a mast mounted retention mechanism similar to FIG. 11.