Fork truck service lift

• US 4,531,614 A
• Filed: 07/25/1983
• Issued: 07/30/1985
• Est. Priority Date: 07/25/1983
• Status: Expired due to Term

• Current Assignee: Handling Specialty Incorporated
• Original Assignee: Autoquip Incorporated
• Inventors: Naegeli, Robert W.
• Primary Examiner(s): Rolla, Joseph J.
• Assistant Examiner(s): Pedersen, Nils E.
• Application Number:
  US06/516,875
• Time in Patent Office: 736 Days
• Field of Search: 187/8.43, 187/8.45, 187/8.5, 187/8.54, 187/8.74, 187/8.41, 254/89 H, 254/89 R
• US Class Current: 187/240
• CPC Class Codes: B66F 7/04 hydraulically or pneumatically operated

Abstract

A portable hydraulic service lift for elevating equipment such as industrial vehicles. The lift includes a base assembly including a platform which supports the elevated lift and allows the lift to be readily moved to a different location. A pair of rigid support legs extend upwardly from one end of the base platform and are spaced transversely to receive a portion of the equipment to be elevated therebetween. A pair of elongate lifting arms are joined in a cantilevered fashion to the support legs along the sides of the base platform. Rollers join the lifting arms to the adjacent support leg so that the arms can be raised and lowered in a cantilevered fashion while rolling along the support legs. Lifting bars extending transversely across the lifting arms are adapted to engage with the underside of the vehicle to be lifted. Power lifting mechanism are provided to raise and lower the arms and the vehicle supported on the lifting bars. Safety locking mechanism connected between said lifting arms and support legs releasably locks the arms in any of a plurality of positions. Control mechanism are also provided to energize the lifting mechanism and safety locking mechanism to selectively raise and lower said arms and said equipment.

Claims

1. A portable service lift for elevating equipment such as industrial vehicles comprising:

a base assembly for supporting said lift in a movable manner at one location and for allowing the lift to be readily moved to another location, said base assembly including a base platform having a selected length and width and onto which the equipment to be elevated can be driven;

a pair of support legs joined to and extending upwardly from said base platform, said legs being transversely spaced and disposed at opposite sides of one end of said platform to define a substantial opening therebetween for receiving a portion of the equipment to be elevated;

a pair of elongated lifting arms positioned on the outside of said opposite sides of said platform, each arm having a rear end adjacent one of said support legs and extending forwardly along a side of said platform so that equipment placed on said platform is positioned between said arms and the area beneath said arms when lifted is totally unobstructed in a direction transversely across said platform;

means for movably joining each lifting arm in cantilevered fashion to the adjacent support leg including support means rigidly joined to each arm adjacent said rear end and extending upwardly adjacent the associated support leg;

first roller means rotatably mounted on said support means in rolling engagement with a front face on the associated support leg; and

second roller means rotatably mounted on said suport means in rolling engagement with an opposing rear face on the associated support leg and spaced vertically a selected distance from said first roller means;

whereby said first and second roller means continuously support said cantilevered lifting arms of said support legs as said arms are raised or lowered with respect to said base platform;

first lifting bar means extending transversely across the rear ends of said lifting arms in a position to extend beneath one portion of said equipment to be lifted as said equipment is moved onto said base platform;

second lifting bar means having a length selected to extend across said lifting arms beneath another portion of said equipment stationed on said base platform, whereby said first and second lifting bar means engage with and support spaced portions of said equipment as said lifting arms are raised with respect to said base platform;

lifting means operably associated between the rear ends of said lifting arms and said support legs for raising and lowering said arms along said support legs to raise and lower said equipment supported between said arms;

safety locking means connected between at least one of said lifting arms and support legs and operable to releasably lock said arms in any of a plurality of elevated positions as said arms and equipment are raised with respect to said base platform; and

control means selectively operable to energize said lifting means and to release said safety locking means so that said equipment can be selectively raised and lowered with respect to said base platform.

2. A portable service lift in accordance with claim 1 wherein said safety locking means comprises an elongate ratchet positioned to extend vertically and connected to one of said support legs and a pawl joined to the adjacent lifting arm in a position to releasably engage said ratchet as said lifting arm is raised with respect to said support leg.

3. A portable service lift in accordance with claim 2 wherein said pawl includes indicia to visually differentiate between the location of said pawl in a locked position engaged with said ratchets and an unlocked position released from said ratchets.

4. A portable service lift in accordance with claim 2 wherein said pawl is biased into engagement with said ratchet and wherein said lift includes releasing means selectively operable to overcome said biasing means and release said pawl from engagement with said ratchet.

5. A portable service lift in accordance with claim 4 wherein said releasing means comprises an expandable hydraulic cylinder connected to said pawl and activated by said control means.

6. A portable service lift in accordance with claim 2 wherein each adjacent lifting arm and support leg is provided with a safety locking means comprising said elongate ratchet and said engaging pawl.

7. A portable service lift in accordance with claim 6 wherein said lift includes a hydraulic cylinder connected to each of said pawls and adapted to be activated by said control means to release said pawls from engagement with the associated ratchet and thereby release said safety locking means.

8. A portable service lift in accordance with claim 6 wherein each pawl includes indicia to visually differentiate between the location of said pawls in a locked position engaged with said ratchet and an unlocked position released from said ratchet.

9. A portable service lift for elevating equipment such as industrial vehicles comprising:

a base assembly for supporting said lift in a movable manner at one location and for allowing the lift to be readily moved to another location, said base assembly including a base platform having a selected length and width for receiving the equipment to be elevated;

a pair of support legs joined to and extending upwardly from said base platform, said legs being transversely spaced along opposite sides of said platform to define a substantial opening therebetween for receiving a portion of the equipment to be elevated;

a pair of elongated lifting arms positioned on opposite sides of said platform, each arm having a rear end adjacent one of said support legs and extending forwardly along a side of said platform so that equipment placed on said platform is positioned between said arms;

means for movably joining each lifting arm in cantilevered fashion to the adjacent support leg including support means rigidly joined to each arm adjacent said rear end and extending upwardly adjacent the associated support leg;

first roller means rotatably mounted on said support means in rolling engagement with a front face on the associated support leg; and

second roller means rotatably mounted on said support means in rolling engagement with an opposing rear face on the associated support leg and spaced vertically a selected distance from said first roller means, whereby said first and second roller means continuously support said cantilevered lifting arms on said support legs as said arms are raised or lowered with respect to said base platform;

a rigid fixed lifting bar extending transversely between the rear ends of said lifting arms in a position to receive one end of the equipment to be lifted, said fixed lifting bar including an upwardly projecting gripping edge extending along the forward portion of said bar to firmly engage the equipment to be lifted with said bar;

second lifting bar means having a length selected to extend across said lifting arms beneath another portion of said equipment stationed on said base platform, whereby said first and second lifting bar means engage with and support spaced portions of said equipment as said lifting arms are raised with respect to said base platform;

lifting means operable for raising and lowering said arms along said support legs to raise and lower said equipment supported between said arms;

safety locking means connected between at least one of said lifting arms and support legs and operable to releasably lock said arms in any of a plurality of elevated positions as said arms and equipment are raised with respect to said base platform; and

control means selectively operable to energize said lifting means and to release said safety locking means so that said equipment can be selectively raised and lowered with respect to said base platform.

10. A portable service lift for elevating equipment such as industrial vehicles comprising:

a base assembly for supporting said lift in a movable manner at one location and for allowing the lift to be readily moved to another location, said base assembly including a base platform having a selected length and width for receiving the equipment to be elevated and a removable ramp adapted to mechanically interlock with a front end of said base platform so that said equipment to be elevated can be easily placed on said base platform and said ramp can be removed readily from said platform, said mechanical interlock between said ramp and base platform comprising a tongue and groove connection;

a pair of support legs joined to and extending upwardly from said base platform, said legs being transversely spaced along opposite sides of said platform to define a substantial opening therebetween for receiving a portion of the equipment to be elevated;

a pair of elongated lifting arms positioned on opposite sides of said platform, each arm having a rear end adjacent one of said support legs and extending forwardly along a side of said platform so that equipment placed on said platform is positioned between said arms;

means for movably joining each lifting arm in cantilevered fashion to the adjacent support leg including support means rigidly joined to each arm adjacent said rear end and extending upwardly adjacent the associated support leg;

first roller means rotatably mounted on said support means in rolling engagement with a front face on the associated support leg; and

second roller means rotatably mounted on said support means in rolling engagement with an opposing rear face on the associated support leg and spaced vertically a selected distance from said first roller means, whereby said first and second roller means continuously support said cantilevered lifting arms on said support legs as said arms are raised or lowered with respect to said base platform;

first lifting bar means extending transversely across the rear ends of said lifting arms in a position to extend beneath one portion of said equipment to be lifted as said equipment is moved onto said base platform;

second lifting bar means having a length selected to extend across said lifting arms beneath another portion of said equipment stationed on said base platform, whereby said first and second lifting bar means engage with and support spaced portions of said equipment as said lifting arms are raised with respect to said base platform;

lifting means operable for raising and lowering said arms along said support legs to raise and lower said equipment supported between said arms;

safety locking means connected between at least one of said lifting arms and support legs and operable to releasably lock said arms in any of a plurality of elevated positions as said arms and equipment are raised with respect to said base platform; and

control means selectively operable to energize said lifting means and to release said safety locking means so that said equipment can be selectively raised and lowered with respect to said base platform.

11. A portable service lift for elevating equipment such as industrial vehicles comprising:

a base assembly for supporting said lift in a movable manner at one location and for allowing the lift to be readily moved to another location, said base assembly including a base platform having a selected length and width for receiving the equipment to be elevated;

a pair of support legs joined to and extending upwardly from said base platform, said legs being transversely spaced along opposite sides of said platform to define a substantial opening therebetween for receiving a portion of the equipment to be elevated;

a pair of elongated lifting arms positioned on opposite sides of said platform, each arm having a rear end adjacent one of said support legs and extending forwardly along a side of said platform so that equipment placed on said platform is positioned between said arms;

means for movably joining each lifting arm in cantileverd fashion to the adjacent support leg including support means comprising a pair of spaced gusset plates rigidly joined to each arm adjacent said rear end and extending upwardly adjacent the associated support leg;

first roller means rotatably mounted between said spaced gusset plates in rolling engagement with a front face on the associated support leg; and

second roller means rotatably mounted between said spaced gusset plates in rolling engagement with an opposing rear face on the associated support leg and spaced vertically a selected distance from said first roller means, whereby said first and second roller means continuously support said cantilevered lifting arms on said support legs as said arms are raised or lowered with respect to said base platform;

first lifting bar means extending transversely across the rear ends of said lifting arms in a position to extend beneath one portion of said equipment to be lifted as said equipment is moved onto said base platform;

second lifting bar means having a length selected to extend across said lifting arms beneath another portion of said equipment stationed on said base platform, whereby said first and second lifting bar means engage with and support spaced portions of said equipment as said lifting arms are raised with respect to said base platform;

lifting means operable for raising and lowering said arms along said support legs to raise and lower said equipment supported between said arms, said lifting means comprising a hydraulic ram extending upwardly along the outer side of each support leg and connected between said base assembly and at least one gusset plate of the adjacent lifting arm so that the hydraulic expansion of said ram applies a substantial lifting force to the respective lifting arm through the gusset plate;

safety locking means connected between at least one of said lifting arms and support legs and operable to releasably lock said arms in any of a plurality of elevated positions as said arms and equipment are raised with respect to said base platform; and

control means selectively operable to energize said lifting means and to release said safety locking means so that said equipment can be selectively raised and lowered with respect to said base platform.

12. A portable service lift for elevating equipment such as industrial vehicles comprising:

a base assembly for supporting said lift in a movable manner at one location and for allowing the lift to be readily moved to another location, said base assembly including a base platform having a selected length and width and onto which the equipment to be elevated can be driven;

a pair of support legs joined to and extending upwardly from said base platform, said legs being transversely spaced and disposed at opposite sides of one end of said platform to define a substantial opening therebetween for receiving a portion of the equipment to be elevated;

a pair of elongated lifting arms positioned on the outside of said opposite sides of said platform, each arm having a rear end adjacent one of said support legs and extending forwardly along a side of said platform so that equipment placed on said platform is positioned between said arms and the area beneath said arms when lifted is totally unobstructed in a direction trnasversely across said platform;

means for movably joining each lifting arm in cantilevered fashion to the adjacent support leg including support means rigidly joined to each arm adjacent said rear end and extending upwardly adjacent the associated support leg;

first roller means rotatably mounted on said support means in rolling engagement with a front face on the associated support leg; and

second roller means rotatably mounted on said support means in rolling engagement with an opposing rear face on the associated support leg and spaced vertically a selected distance from said first roller means;

whereby said first and second roller means continuously support said cantilevered lifting arms on said support legs as said arms are raised or lowered with respect to said base platform;

first lifting bar means extending transversely across the rear ends of said lifting arms in a position to extend beneath one portion of said equipment to be lifted as said equipment is moved onto said base platform;

second lifting means having a length selected to extend across said lifting arms beneath another portion of said equipment stationed on said base platform, whereby said first and second lifting bar means engage with and support spaced portions of said equipment as said lifting arms are raised with respect to said base platform; and

lifting means operably associated between the rear ends of said lifting arms and said support legs for raising and lowering said arms along said support legs to raise and lower said equipment supported between said arms.