US3048238A

US3048238A - Automatic jack for a vehicle hoist

Info

Publication number: US3048238A
Application number: US123152A
Authority: US
Inventors: George A Wallace
Original assignee: Globe Hoist Co
Current assignee: Globe Hoist Co
Priority date: 1961-07-11
Filing date: 1961-07-11
Publication date: 1962-08-07
Anticipated expiration: 1979-08-07

Description

Aug. 7, 1962 G. A. WALLACE 3,048,238

AUTOMATIC JACK FOR A VEHICLE HOIST Filed July 11, 1961 2 Sheets-Sheet 1 INVENIOR Q 40 GeorgeAWallace 55 "-44:1-

ATTORNEY 5 8,848,238 Patented Aug. 7, 1962 3,648,238 AUTUMATIC JAK FQR A VEHICLE HOIST George A. Waliace, Philadelphia, Pa, assignor to Globe Hoist Company, Philadelphia, Pin, a corporation of Maryland Filed Italy 11, 1961, Ser. No. 123,152 15 Claims. (Cl. 1878.'74)

This invention relates to an automatic jack arrangement for a vehicle hoist which automatically flips between horizontal-folded and upright-extended positions when the hoist is lowered and raised to and from the ground, and it more particularly relates to such an arrangement for hoisting vehicles having a torsion housing such as Volkswagens.

A vehicle hoist designed specifically for lifting smaller foreign automobile having torsion housing such as Volkswagens utilizes hinged flippers to engage the torsion housing at the rear end of the vehicle. These flippers are manually folded down fiat against the superstructure to eliminate the hazard that they present when the hoist is resting upon the ground to the walking about it and to a car being driven over it. However, this manual opera tion is inconvenient, particularly When they must be extended to the upright position after a vehicle has been driven over them. In addition, it is easy to forget to fold the flippers down when the hoist is lowered.

An object of this invention is to provide a simple and economical arrangement for automatically flipping jacks upon a vehicle hoist between upright-extended and horizontally-folded positions.

Another object is to provide such an arrangement which automatically folds the jacks when the hoist is lowered and raises them to their extended-upright position when the hoist is raised.

In accordance with this invention a plunger slides up and down within a vertical well in the superstructure and extends below it for contacting the ground when the hoist is lowered. A finger bar is rotatably connected below the superstructure, and it is connected to the plunger through a projection and slot coupling. The outer end of the finger bar includes a cam surface which engages the end of a jack extension, and a resilient force reacts between the jack and superstructure in a direction to maintain the jack urged into its upright position and the finger bar and plunger urged downwardly to a lower limit of travel when the hoist is raised from the ground. When the hoist is lowered to the ground, the plunger is forced upwardly into its well which causes the finger bar to rotate upwardly to flip the jack into its horizontal folded position against the resilient upright biasing force.

Novel features and advantages of the present invention will become apparent to one skilled in the art from a reading of the following description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

FIG. 1 is a top perspective view of one embodiment of this invention in the folded position;

FIG. 2 is a bottom perspective view of the embodiment shown in FIG. 1 in the upright position as it is supporting a vehicle;

FIG. 3 is a plan view of the embodiment shown in FIG. 2;

FIG. 4 is a cross-sectional view in elevation taken through FIG. 3 along the line 44;

FIG. 4A is a perspective view of part of the embodiment shown in FIG. 4;

FIG. 5 is a cross-sectional View in elevation similar to FIG. 4 in the folded position; and

FIG. 6 is an end view of a portion of the embodiment shown in FIG. 4.

In FIGS. 1 and 2 are shown a pair of jack arrangements 10 mounted upon a vehicle hoist 12 especially designed for lifting a relatively smaller foreign vehicle 14 such as a Volkswagen which includes a torsion housing 16 at its rear end. Hoist 12 includes a superstructure 1'7 incorporating a bolster 18 mounted upon a piston 28 with a plate or transverse bar 22 mounted across its rear end. The pair of jack arrangements 18 are arranged to fold oppositely toward each other upon the outer ends of plate 22 for engaging torsion housing 16 at the rear end of the vehicle to lift it as shown in FIG. 2. The front of the vehicle is supported upon one of a pair of

contact pads

24 or 26 dependent upon the length of the vehicle being lifted as shown in FIG. 2. Contact pads 24 are used for lifting passenger vehicles, and contact pads 26 are used for lifting bus models of the Volkswagen type.

Jack arrangements 18 are shown in FIG. 1 in the folded position to which they are automatically flipped when hoist 12 is fully lowered to the ground. This insures that they will not project above floor level to trip unsuspecting persons or to damage parts of vehicles driven over the hoist and being aligned over it by engagement of its tires within wheel wells 28.

FIG. 2 shows the upright position of jack arrangements 18 to which they are automatically flipped by this invention as soon as the hoist rises from the ground. Details of this automatic arrangement are described in the following.

In FIGS. 3 and 4, jack plates 30, hereinafter referred to as jacks 30, are illustrated in the upright position in which a lower surface 32 rests against and is supported upon plate 22. Jacks 30 are rotatably connected beneath plate 22 by insertion of their pivot shafts 3 3 within bearing tubes 34 secured to plate 22 by support blocks 36. Pivot shafts 33 extend from a pair of flanges 38 secured to the sides of jack 30 to provide an offset pivot means 40 for permitting jacks 30 to rotate from the upright position shown in FIGS. 3 and 4 to the horiozntally folded position shown in FIG. 5.

An extension 42 of jacks 30 past its axis of rotation or pivot means 40 extends below superstructure 17 in the upright position shown in FIG. 4. Extension 42 is disposed at the end of a tongue 44 which passes through a slot 45 in the end of plate 22. Flange 46 is connected to the end of extension 42 to provide an extended bearing surface, which is part of the flipping arrangement as is described later in detail. A plunger 48 slides vertically within a well 56' in block 52 secured below plate 22. Plunger 48 extends below superstructure 17 with a foot extension 54 for contacting the ground when hoist 12 is lowered. Foot extension 54 includes a cap screw 56 threaded into a vertical hole 58 provided within plunger 48, which is for example cylindrical in form. Lock nut 60 provides a means for adjustably securing cap screw 56 to the bottom of plunger 48.

As shown in FIGS. 3 and 4, a projecting rod 62 extends through plunger 48, and it is secured to it by a force fit engagement within plunger 48. After rod 62 is secured to plunger 48, tapped hole 64 through rod 62 and clearance hole 66 permit the shank of screw 56 to pass upwardly through the entire length of plunger 48 to facilitate the adjustment of the distance of its head below hoist 12.

A finger or actuating bar or lever 68 is rotatably connected below superstructure 17 upon the horizontal axis of rotation provided by shaft 70 secured to block 52, which is received within the forked end 72 of finger bar assembly 68. Forked end 72 is provided by a pair of side plates 74 which extend from the outer end 76 of finger bar assembly 68. Outer end 76 includes a substantially rounded cam surface 78 which engages jack extension 42 and flange 46 upon tongue 44 of jack 30.

The portion of side plates 66 adjacent plunger 48 each include a pair of open-ended slots 80 which are engaged by projecting rod 62 to movably connect plunger 48 to finger bar 68. An extension 82 of side plates 74 past pivot shaft 70 contacts the bottom of plate 22 when finger bar 68 drops to a lower limit of travel to provide a stop defining this lower limit for finger bar 68 and plunger 48. A welsh plug 84 seals the top of well 50 to seal it from dirt and foreign objects. A lightening hole 86 is provided in jack 30 to conserve metal and weight.

A resilient means 88, provided by a tension spring of the same number, reacts between superstructure 17 and a portion of flange 38 of jack 30 past pivot 40 for maintaining jack 30 resiliently urged into the upright position and through its contact with finger bar 68 and plunger 48 maintaining them urged toward their lower position. Spring 88 is connected to bolster 18 by lug 90* and to flange 38 by one of lugs 92. A pair of lugs 92 are provided upon jacks 38, but only one is utilized in each opposite hand orientation of jack 30.

Operation In the upright position shown in FIG. 4, spring 88 can maintain jack 30 flipped to the upright position because jack extension 42 and flange 46 formed upon tongue 44 are unrestrained in their reaction against cam surface 78, which rotates finger bar 68 and connected plunger 48 downwardly to their lower limit of travel, because the head of cap screw 56 is raised off the ground. Stop surface 82 upon finger bar 68 supports finger bar 68 and plunger 48 in the position shown in FIG. 4 while jack 30 is supported by its lower surface 32 which rests upon plate 22 to permit it to lift vehicles within its upper receiving surfaces 94, which engage torsion housing 16 as shown in FIG. 2.

When hoist 12 is lowered to the ground, as shown in FIGS. 1 and 5, cap screw 56 is pushed upwardly by contacting ground level 96 which forces plunger 48 upwardly into well 58 and accordingly rotates finger bar 68 upwardly. Cam surface 78 at the outer end 76 of finger bar 68 pushes against jack extension 42 and flange 46 upon tongue 4-4 thereby flipping jack 30 from the upright position shown in FIG. 4 to the folded position shown in FIG. 5. Throughout this flipping movement, rounded surface 78 maintains a forceful sliding engagement with jack extension 42 and flange 46 to positively flip jack 38 into the folded position and maintain it so held as long as cap screw 56 is pushed upwardly within well 50 by being lowered into contact with ground level 96. As shown in FIG. 5, cam surface 78 maintains its engagement with flange 46 in the folded position to maintain jack 30 securely folded against plate 22 as long as hoist 12 rests on the ground. The distance of cam surface 78 from pivot shaft 70, about which finger bar 68 is rotatably mounted, is greater than the corresponding moment arm of projecting pin 62 within slot 80 to provide a corresponding greater movement of cam surface 78 relative to that of pin 62. This converts a relatively slight movement of plunger 48 into the much greater movement which is necessary to flip jack 30' into the folded position. This structure accordingly provides a remarkably great amount of flipper rotation from a slight upward plunger movement which can be accommodated within a hoist superstructure, which should be maintained as close to ground level as possible. Furthermore, the adjustability of foot extension 54 provided by the great distance that cap screw 56 can be inserted Within clearance hole 66 in plunger 48 provides a remarkably great range of adjustment for this arrangement which the great variations in ground level below the superstructure at various installations require. This device may accordingly be adjusted to operate effectively with ground levels that vary as much as two inches with the illustrated cap screw 56 of approximately that length and up to approximately five inches by utilizing longer cap screws where required.

This arrangement accordingly provides a highly useful automatic means for operating jack arrangements It also has the unexpected advantage of completely avoiding the heretofore awkward duty of bending under a car positioned over the hoist to flip the jacks up into engagement with the torsion housing. This invention therefore provides both unexpected convenience in operation as well as insuring the elimination of hazardous projections at ground level.

What is claimed is:

1. A jack arrangement which automatically flips between upright and horizontal positions upon a vehicle hoist superstructure comprising a horizontal supporting plate mounted upon said superstructure, ofiset pivot means mounting said jack upon said plate for movement from said horizontal position folded flat against said plate to said upright position in which a lower surface is supported upon said plate, a plunger inserted to slide up and down within a vertical well in a lower portion of said superstructure, said plunger extending below said superstructure for contacting said ground whereby it is pushed upwardly into said well, the upper end of said jack in said upright position having a surface for engaging a lower portion of a vehicle, an extension of said jack past its axis of rotation extending below said superstructure in said upright position, a finger bar rotatably connected below said superstructure upon a horizontal axis of rota tion and extending past said plunger with an outer end disposed adjacent said jack extension, projection and slot means connecting said finger bar to said plunger to cause upward movement of said plunger to rotate said finger bar upwardly and move said outer end of said finger bar toward said jack extension, a cam surface upon said outer end of said finger bar which engages the end of said jack extension, resilient means reacting between said jack and said superstructure in a direction to urge said jack into said upright position and said finger bar and plunger urged downwardly, stop means retaining said plunger within said well, and said cam surface bearing against the end of said jack extension throughout its angular movement for flipping it into and maintaining it urged into said flat horizontal position when said plunger is moved upwardly into said well by forceful contact with said ground.

2. A jack arrangement as set forth in claim 1 wherein a pair of said jacks are arranged to fold oppositely toward each other upon an extended horizontal supporting plate which is disposed upon said superstructure in a position substantially perpendicular to the axis of a vehicle supported upon it.

3. A jack arrangement as set forth in claim 1 wherein said end of said jack extension includes a flange which extends downwardly in said horizontal folded position to provide an extended bearing surface for contact by said cam surface upon said finger bar.

4. A jack arrangement as set forth in claim 1 wherein said cam surface comprises a substantially rounded projection upon the upper surface of said outer end of said finger bar.

5. A jack arrangement as set forth in claim 1 wherein said well is included in a block which is secured to the bottom of said plate, said finger bar includes a forked end, and said block being inserted within said forked end which is rotatably connected to said block.

6. A jack arrangement as set forth in claim 5 wherein said forked end includes a pair of side plates, the end of said plates remote from said outer end of said finger bar being rotatably connected to said block, a slot in the portion of said side plates adjacent said plunger, and said projection being secured to said plunger and engaging said slot.

7. A jack arrangement as set forth in claim 6 wherein said projection comprises a rod secured to said plunger.

8. A jack arrangement as set forth in claim 7 wherein said plunger includes a vertical hole, and a foot extension being adjustably secured Within said hole to permit the actuation of said projection to be adjusted in accordance with variations in ground height.

9. A jack arrangement as set forth in claim 8 wherein said foot extension comprises a cap screw, said hole being threaded to receive said cap screw, and a locknut being attached to said cap screw adjacent said plunger for securing said cap screw thereto.

10. A jack arrangement as set forth in claim 1 wherein an adjustable foot extension is secured to the bottom of said plunger for adjusting the actuation of said jack arrangement in accordance with variations in ground height.

11. A jack arrangement as set forth in claim 1 wherein said offset pivot means is arranged upon a pair of flanges extending from said jack, and said resilient means comprises a tension spring connected between a lower portion of said superstructure and a portion of one of said flanges extending past said pivot means.

12. A jack arrangement as set forth in claim 1 wherein said stop means comprises an extension of said finger bar past its horizontal axis of rotation which contacts said superstructure when said finger bar drops to a lower limit of travel.

13. A jack arrangement as set forth in claim 12 wherein said finger bar includes a central actuating portion inporating said cam surface and a forked end which is rotatably secured to said superstructure, said forked end including a pair of side plates, said plunger being inserted within said side plates, a pair of slots in said side plates, said projection being secured to said plunger and engaging said slots, and said extension of said finger bar comprising a surface at the top of each of said side plates which contacts said superstructure when said finger bar drops to said predetermined lower limit of travel.

14-. A jack arrangement as set forth in claim 1 wherein said horizontal supporting plate includes a slot, and said jack extension includes a tongue which passes through said slot below said superstructure when it is in said upright position for engagement by said cam surface.

15. A jack arrangement which automatically flips between upright and horizontal positions upon a vehicle hoist superstructure comprising a horizontal supporting plate mounted upon said superstructure, offset pivot means mounting said jack upon said plate for movement from said horizontal position folded fiat against said plate to said upright position in which a lower surface is supported upon said plate, a foot extending below said superstructure, motion-permitting means connecting said foot to said superstructure in a manner which allows it to be pushed upwardly relative to said superstructure when it is contacted against the ground by movement of said superstructure towards said ground, the upper end of said jack in said upright position having a surface for engaging a lower portion of a vehicle, an extension of said jack past its axis of rotation extending below said superstructure in said upright position, a finger bar rotatably connected below said superstructure upon a horizontal axis of rotation and extending past said foot with an outer end disposed adjacent said jack extension, loose connecting means coupling said finger bar to said foot to cause upward movement of said foot to rotate said finger bar upwardly and move said outer end of said finger bar toward said jack extension, a cam surface upon said outer end of said finger bar which engages the end of said jack extension, resilient means reacting between said jack and said superstructure in a direction to urge said jack into said upright position and said finger bar and foot urged downwardly, and said cam surface bearing against the end of said jack extension throughout its angular movement for flipping it into and maintaining it urged into said flat horizontal position when said foot is urged upwardly by forceful contact with said ground.

References Cited in the file of this patent UNITED STATES PATENTS 777,398 Casgrain Dec. 13, 1904 1,955,586 Hott et al Apr. 17, 1934 2,098,376 Cunneen Nov. 9, 1937