US3837434A - Door structure for recessed auto lift - Google Patents

Abstract

A vehicle lift has a hydraulic cylinder and a U-shaped bolster, both of which are retracted in the floor when the lift is in the lowered position. A first door, positioned within the area defined by the bolster, rests on the floor when the bolster is in the lowered position and is picked up by the bolster when the vehicle is lifted. A second door is positioned about the ram below the bolster and rides on four pivoted arms. Springs connected to the arms supply force for raising the arms and the second door as the vehicle is raised. As the second door approaches the floor level, the arms pivot across vertical and are blocked from further pivotal movement in that direction so that they become rigid posts to support the second door at the floor level. Cams on the bolster operatively engage the arms as the bolster descends so as to pivot the arms back across the vertical position and allow them to descend as the bolster presses downwardly on the second door.

Description

nited States Patent 1191 Clarke 1 51 Sept. 24, 1974 DOOR STRUCTURE FOR RECESSED AUTO Primary Examiner-Richard A. Schacher LIFT Assistant Examiner-Jeffrey V. Nase [75] Inventor: Jesse E. Clarke, Hinsdale, Ill. Attorney Agent or Flrm Darbo Robertson &

Vandenburgh [73] Assignee: Autoquip Corporation, Chicago, Ill. [22] Filed: July 3, 1972 ABSTRACT [2]] Appl' 268,798 A vehicle lift has a hydraulic cylinder and a U-shaped bolster, both of which are retracted in the floor when Related Appllcatlon Data the lift is in the lowered position. A first door, posi- [63] Continuation of Ser. No. 98,737, Dec. I6, 1970. tioned within the area defined by the bolster, rests on the floor when the bolster is in the lowered position [52] US. Cl. 187/8.62, l87/8.6l and is picked up by the bolster when the vehicle is [5]] Int. Cl B66f 7/00 lifted. A second door is positioned about the ram [58] Field of Search l87/8.6l, 8.62 below the bolster and rides on four pivoted arms. Springs connected to the arms supply force for raising the arms and the second door as the vehicle is raised. [56] References Cited As the second door approaches the floor level, the

UNITED STATES PATENTS arms pivot across vertical and are blocked from fur- 2 524 237 H1950 Smith I 187/8 62 ther pivotal movement in that direction so that they 2 577 378 12/1951 saint;;311iIIi""'"IIIIIIIIII 187/832 4 become rigid Posts to Support the Second door at the 2:588:5l8 3/1952 Grushon l87/8.62 floor lfivel- Cams the bolster Operatively engage the 2,655,224 10 1953 ou et 1 187/852 arms as the bolster descends so as to pivot the arms 2,732,917 1/1956 Hecker 187/8.62 back across the vertical position and allow them to de- 2,961,069 11/1960 Webster 187/8.62 scend as the bolster presses downwardly on the second 3,393,772 7/1968 Pelouch g l87/8.62 x dom 3,608,675 /1971 Sherry 187/862 7 Claims, 5 Drawing Figures PAIENIEnswzwu sum-1w Q INVENTOR. F I G. 3

JESSE E. CLARKE wmm i PAIENIEnSarzmn samurai FIG. 4

INVENTOR. JESSE E. CLARKE' 1 DOOR STRUCTURE FOR RECESSED AUTO LIFT This is a continuation of application Ser. No. 98,737 filed Dec. 16, 1970.

BACKGROUND AND SUMMARY OF THE INVENTION A desirable characteristic of a vehicle lift is that it minimizes the obstruction of the bottom of the car; thereby, a mechanic is given the maximum amount of freedom of access to the bottom of the car to work on it. In the present invention, a U-shaped bolster is employed having a base with two upwardly extending posts. A single hydraulic ram supports the bolster at the center of the base. The vehicle engaging structure is supported on the upper ends of the posts. Preferably, this vehicle supporting structure is a plurality of jointed arms.

It will be noted that if such a U-shaped bolster is to have any appreciable depth (and thus provide significant clearance for working space) it is necessary that the bolster be recessed in the floor to permit the vehicle to be moved on or off the lift. This necessitates an opening in the floor. It is highly desirable that any such floor opening have a door which will close the opening when the lift is retracted into the floor and which will also close the opening when the lift and vehicle are raised. Without such a door, debris, tools, etc., will fall through the floor opening. Furthermore, with the lift in the raised position, there is a danger of a person stepping into the floor opening or tripping over it, with resulting injury. Also, in some servicing operations performed on a vehicle, various objects are moved about the floor under the car. These require floor support when moving across or standing on the area occupied by the vehicle lift floor opening. Sometimes such objects have an appreciable weight and it is necessary that the door be able to withstand significant loads. Another requisite of such a door structure is that it be relatively simple, relatively inexpensive and foolproof in operation. The principal object of the present invention is to provide a door structure that will solve these various problems.

In the present invention, this is accomplished by using two doors, one of which rests on the floor when the lift is recessed. As the bolster rises out of the floor this first door is picked up by the base of the bolster and is thereby out of the way as much as is the base of the bolster. A second door below the bolster is raised into position by a plurality of pivoted arms which move across center so as to securely support the second door across the floor opening DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an embodiment of the inventron;

FIG. 2 is an elevational view of the lift as seen below floor level, with portions broken away, and with the lift in the retracted position;

FIG. 3 is a section taken at line 3-3 of FIG. 4;

FIG. 4 is a view corresponding to that of FIG. 2 with the bolster raised above the floor; and

FIG. 5 is a fragmentary view similar to FIG. 4 but showing the bolster in the act of camming down the arms so that the lower door will descend.

DESCRIPTION OF SPECIFIC EMBODIMENT The following disclosure is offered for public dissemination in return for the grant of a patent. Although it is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

The lift of the present invention is powered by a ram 10 mounted in a hydraulic cylinder, not shown. Secured to the top of the ram is a bolster, generally 11, comprising a base 12 and a pair of vertical posts 13 and 14. Secured to the top of posts 13 and 14 is the vehicle engaging superstructure. Any such vehicle engaging superstructure could be employed with the present invention, although I prefer to use jointed links, generally 15, as, for example, shown in my prior US. Pat. No. 3,315,764. These are secured to plates 16 affixed to the tops of the bolster posts. There is a vertical rod 17 to prevent rotation of the ram and superstructure.

A frame, generally 19, forms a recess in the floor to receive the bolster l1 and defines an opening 20 at floor level. This frame includes a top plate 21, two side plates 22 and end walls 18. Above the base 12 of the bolster is a first door 23. Door 23 is only slightly shorter than the distance between the two arms 13 and 14 of the bolster. It has recesses 24 so that the door fits about a pair of guides 25 secured to the inner faces of the posts.

A second door 28 is positioned below bolster l1 and fits loosely about the ram 10 and the anti-rotating rod 17 so that these are free to move vertically with respect to the second door. Door 28 rides on a plurality of rollers 29 secured to the distal ends of levers or arms 30. The proximal ends of arms 30 are welded to shafts 31 journaled in bearings 32. There are four such arms secured to two shafts. The arms have projections 33. Springs 34 connect pins 35 on projections 33 and pins 36 on frame 19.

With the ram and bolster in the retracted position, as illustrated in FIG. 2, the door 23 is resting on the top 21 of the frame and thereby closes that part of the opening 20 between the bolster posts. The door 28 is held down against the tension of springs 34 by the bolster. As the bolster initially is raised from the lowered position, the lowered door 28 follows the bolster up. When base 12 of the bolster reaches the upper door 23 it picks up the upper door and carries it out of the way, as illustrated in FIGS. 3 and 4. For all practical purposes, the upper door 23 provides no more obstruction to the under side of the vehicle than does the bolster base 12. As the bolster moves above the floor opening, the arms 30 raise the lower door 28 to the floor level.

An important facet of the present invention is that the pivotal axes of the levers 30 are positioned so that the levers move across center" in the final part of the range of movement. Thus, the shafts 31, which define the pivotal axes, are positioned inwardly from end walls 18 which serve as the final stop for the pivotal movement of the levers. When the levers move across the vertical position and over against stops forming a part of end walls 18, any pressure on the floor 28 only presses the levers that much harder against their stops so that the levers then serve as rigid posts to support the door 28.

When the bolster 11 is to descend, the levers 30 must be moved back across center (across the vertical position) so that they will permit the descent of door 28. To achieve this, there are cams 37 on each end of the bolster. As best seen in FIGS. 3 and 5, these cams 37 descend through slots 38 in door 28 to contact arms 30. Only one such arm 30 at each end need be contacted by a cam since the two arms at an end are pivotally tied together by shaft 31. The angular face of the cam pushes the arms 30 back across center, as best illustrated in FIG. 5, so that as the base 12 of the bolster comes into contact with lower door 28 it can push the door down against the resistance of springs 34. Thus, the lift can retract from the FIG. 4 to the FIG. 2 position.

I claim:

1. In a vehicle lift apparatus of the type comprising a frame, a ram part and a bolster part recessed in a floor in a retracted position with said parts moving through a floor opening when moving from a retracted to a raised position, and a door to close at least a part of said opening when the ram part is in the raised position, the improvement comprising:

said door being a flat plate approximately the size of said opening and, when lowered, positioned horizontally about said ram pa'rt below the bolster part when the parts are in the recessed position and with the ram part being free to move vertically through the door,

means mountd on the frame and operatively connected to the door for horizontally raising the door behind the bolster part as the bolster part moves away from the retracted position until the door reaches the floor opening and then for supporting the door at said opening, said means comprising a plurality of levers having one end thereof pivotally connected to the frame below said opening and the other end bearing against said door, said levers being movable from a first position when said door is in a lowered position to a second position when the door is at said opening, means connecting said levers and frame and resiliently urging said levers in a given direction from the first position toward the second position, and fixed means separate from the levers and positioned to contact the levers and block further movement of the levers in said direction when said levers reach the second position.

2. In a vehicle lift apparatus of the type comprising a frame, a ram part and a bolster part recessed in a floor in a retracted position with said parts moving through a floor opening when moving from a retracted to a raised position, and a door to close at least a part of said opening when the ram part is in the raised position, the improvement comprising:

4 said door being a flat plate approximately the size of said opening and, when lowered, positioned horizontally about said ram part below the bolster part when the parts are in the recessed position and with the ram part being free to move vertically through the door, means mounted on the frame and operatively connected to the door for horizontally raising the door behind the bolster part as the bolster part moves away from the retracted position until the door reaches the floor opening and then for supporting the door at said opening, said means comprising a plurality of levers each having two ends, with one of said ends bearing against the door, a pivotal connection between the other end and the frame, each lever being movable between a first position at which the door is in the lowered position and a second position at which the door is at floor level, said connection being so positioned that the lever passes through and beyond a vertical position as the lever moves between the first position and the second position, and a stop fixed to the frame and positioned to contact the lever after the lever reaches the second position and to prevent the lever from moving beyond the second position when moving in the direction of from said vertical position to said second position. 3. In an apparatus as set forth in claim 2, including means on one of said parts and positioned to operatively engage said lever as the parts descend to move the lever from the second position toward and past said vertical position.

4. In an apparatus as set forth in claim 3, including a spring connecting said lever and said frame and resiliently urging said lever from said first to said second position, and wheel means on said one end of said lever to provide an antifriction contact with said door.

5. In an apparatus as set forth in claim 4, wherein the means to move the lever is a cam extending downwardly from the bolster part.

6. In an apparatus as set forth in claim 5, wherein said bolster part is generally U-shaped with a base and two spaced posts extending upwardly from the base and of a size such that all of the bolster except for the tops of the posts are below the floor opening when the parts are in the retracted position; and

including door means positioned between said posts and above said base.

7. In an apparatus as set forth in claim 6, wherein said door means has a width greater than the width of the floor opening so that the door means will rest on the floor when the parts are retracted, and including means operatively connecting the second door and the bolster part so that the door means will remain on the bolster part when the parts are raised.

Claims (7)

1. In a vehicle lift apparatus of the type comprising a frame, a ram part and a bolster part recessed in a floor in a retracted position with said parts moving through a floor opening when moving from a retracted to a raised position, and a door to close at least a part of said opening when the ram part is in the raised position, the improvement comprising: said door being a flat plate approximately the size of said opening and, when lowered, positioned horizontally about said ram part below the bolster part when the parts are in the recessed position and with the ram part being free to move vertically through the door, means mountd on the frame and operatively connected to the door for horizontally raising the door behind the bolster part as the bolster part moves away from the retracted position until the door reaches the floor opening and then for supporting the door at said opening, said means comprising a plurality of levers having one end thereof pivotally connected to the frame below said opening and the other end bearing against said door, said levers being movable from a first position when said door is in a lowered position to a second position when the door is at said opening, means connecting said levers and frame and resiliently urging said levers in a given direction from the first position toward the second position, and fixed means separate from the levers and positioned to contact the levers and block further movement of the levers in said direction when said levers reach the second position.

2. In a vehicle lift apparatus of the type comprising a frame, a ram part and a bolster part recessed in a floor in a retracted position with said parts moving through a floor opening when moving from a retracted to a raised position, and a door to close at least a part of said opening when the ram part is in the raised position, the improvement comprising: said door being a flat plate approximately the size of said opening and, when lowered, positioned horizontally about said ram part below the bolster part when the parts are in the recessed position and with the ram part being free to move vertically through the door, means mounted on the frame and operatively connected to the door for horizontally raising the door behind the bolster part as the bolster part moves away from the retracted position until the door reaches the floor opening and then for supporting the door at said opening, said means comprising a plurality of levers each having two ends, with one of said ends bearing against the door, a pivotal connection between the other end and the frame, each lever being movable between a first position at which the door is in the lowered position and a second position at which the door is at floor level, said connection being so Positioned that the lever passes through and beyond a vertical position as the lever moves between the first position and the second position, and a stop fixed to the frame and positioned to contact the lever after the lever reaches the second position and to prevent the lever from moving beyond the second position when moving in the direction of from said vertical position to said second position.

3. In an apparatus as set forth in claim 2, including means on one of said parts and positioned to operatively engage said lever as the parts descend to move the lever from the second position toward and past said vertical position.

4. In an apparatus as set forth in claim 3, including a spring connecting said lever and said frame and resiliently urging said lever from said first to said second position, and wheel means on said one end of said lever to provide an antifriction contact with said door.

5. In an apparatus as set forth in claim 4, wherein the means to move the lever is a cam extending downwardly from the bolster part.

6. In an apparatus as set forth in claim 5, wherein said bolster part is generally U-shaped with a base and two spaced posts extending upwardly from the base and of a size such that all of the bolster except for the tops of the posts are below the floor opening when the parts are in the retracted position; and including door means positioned between said posts and above said base.

7. In an apparatus as set forth in claim 6, wherein said door means has a width greater than the width of the floor opening so that the door means will rest on the floor when the parts are retracted, and including means operatively connecting the second door and the bolster part so that the door means will remain on the bolster part when the parts are raised.

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