o l a. United States atent [151 3,635,794 Petry 1 Jan. 18, 1972 SAFETY DOOR FOR VEHICLE LIFT Primary Examiner-Joseph Wegbreit Assistant ExaminerMerle F. Maffei l [72] Inventor John G Petry, San Jose Ca if Attorney ,rownsend and Townsend [73] Assignee: J. D. Cochin Manufacturing Company,

San Francisco, Calif. [57] ABSTRACT Filedi J 1970 A door mechanism for the ends of the rectangular opening of I I the floor box for housing a vehicle lift of the type which is l A l. N 579 [2 1 pp 0 disposed below floor level in the lift box when the lift is at its lowest position. The mechanism includes a pair of swingable [52] US. Cl ..187/8.62, 187/861 f t doors f the end of the opening of the floor box. The [51] 'f "1366f 7/28 safety doors are actuated by the swingable movement of the [58] Field ofSearch ..187/8.6i, 8.62 p of main doors which cover the central portion of the opening of the floor box when the lift is at its lowest position. [56] References cued An actuating arm is provided for each safety door, respective- UNITED STATES PATENTS ly, for moving it into a horizontal position in response to swinging movement of a corresponding mam door. The arm Webster et a1 l also upports the afety door in its horizontal position 3,393,772 7/1968 Pelouch ..l87/8.62 X

8 Claims, 4 Drawing Figures PATENTED m1 8 19. 2

INVENTOR. JOHN G. PETRY 'BY 70mm! CWT/M" m4 ATTORNEYS SAFETY DOOR FOR VEHICLE LIFT This invention relates to improvements in vehicle lifts and, more particularly, to a safety door mechanism for a portion of the opening of a floor box of a vehicle lift of the type which is disposed substantially below floor level when the lift is at its lowest positionl In a particular type of vehicle lift, known as a drive-thru lift, the lifting structure coupled to the vertically reciprocal cylinder is housed in a lift floor box below floor level so that a vehicle can be driven into a position above the lift, whereupon swingable arms on the lifting structure can be moved into positions for engaging the underside of the vehicle when the lift is elevated. The lift floor box has a pair of swingable main doors which move into horizontal positions when the lift is at its lowest position so as to cover the opening or the top of the lift floor box. These main doors move into raised positions as the lift is elevated.

The ends of the top or opening of the lift floor box are occupied by the end portions of the lifting structure when the lift is at its lowest position. The ends of the top or opening must be covered by doors that meet Governmental safety requirements and, to this end, spring-loaded safety doors have been provided for covering these ends when the lift is in its elevated position. Thus, workmen moving beneath the elevated lift will not be subject to the danger of stepping into the lift floor box at the ends thereof. However, because of the spring-loading nature of the doors heretofore used, a chain or other securing device has been required to support the weight of a workman standing on a safety door. While such door structure is satisfactory to some extent, the structure of the door and the supporting means therefor is cumbersome and not completely safe.

The present invention is directed to improvements in the use of safety doors for the ends of the top or opening of a lift floor box of the type described. To this end, the invention includes a pair of safety doors for the ends of the top of a lift floor box wherein each of the safety doors is moved from a recessed condition extending downwardly into the lift floor box to a horizontal position covering the corresponding end of the top or opening of the lift floor box in response to the upward swinging movement of a corresponding main door of the lift floor box. Such movement is caused by an arm rigidly carried by each main door, the arm serving to lift the safety door to a horizontal position as the lift is elevated and to support the safety door in such horizontal position at all times while the lift is elevated. Thus, workmen can walk on the safety doors, in and around the lift without stepping into the lift floor box. Also, the safety doors move into their retracted positions as the lift descends into the floor box. The invention, therefore, eliminates the need for springs and chains for moving and supporting the safety doors and provides a more efficient construction and one which assures maximum safety for workmen beneath the elevated lift.

The primary object of this invention is to provide safety door structure of improved construction for the ends of the top opening of a lift floor box wherein the door structure is shifted into an operative position as a function of the opening of the main door structure of the lift floor box while at the same time, the safety door structure is supported from beneath while the lift is in its elevated position.

Another object of this invention is to provide an improved safety door mechanism for a lift floor box wherein the mechanism includes an arm rigidly secured to a main door of the floor box, the arm being engageable with an adjacent safety door for moving the same into a horizontal position as the main door moves into a raised position and to support the safety door in its horizontal position at all times so long as the main door remains in its raised position.

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawing for an illustration of an embodiment of the invention.

In the drawing:

FIG. I is a perspective view of a vehicle lift of the type which has a lift structure movable into a lift floor box, and showing the safety door mechanism of this invention;

FIG. 2 is an enlarged, fragmentary, perspective view of the safety door mechanism looking upwardly from within the floor box;

FIG. 3 is a cross-sectional view showing the safety door mechanism when the lift is at its lowest position; and

FIG. 4 is a view similar to FIG. 3 but showing the safety door mechanism when the lift is elevated.

The safety door mechanism of this invention is broadly denoted by the numeral 10 and is adapted for use with a vehicle lift 12 of the type having a floor box 14, a vertically reciprocal cylinder 16 movable into and out of the floor box and a lift structure 18 carried on the upper end of cylinder 16. Lift structure 18 includes a pair of upwardly extending anns 20 at the ends of the main lift member 22, each arm 20 having a pair of vehicle-engaging arms 24 pivotally mounted on a pad 26 rigid to the corresponding arm 20. A pair of main doors 28 are coupled by hinges 30 (FIG. 4) to the sides of floor box 14 and these doors move from horizontal, coplanar positions covering the open top of the floor box to raised positions when the lift is moved from a location with lift structure 18 within the lift box to a position with the lift structure out of the lift box. FIG. 3 illustrates the main doors 28 in their horizontal positions when lift structure 18 is disposed within floor box 14 and FIG. 4 illustrates the raised positions of doors 28 when lift structure 18 is above the lift box. In its raised position, each main door 28 leans against cylinder 16 and is thereby inclined. A pad (not shown) is disposed between the main door and the cylinder to protect the surface of the latter. Each main door thus moves through an arc of approximately 65 as it moves from the horizontal position to its raised position.

Since the upper end of the lift box is at the floor level, a vehicle can drive into a position above the lift when lift structure 18 is in the position shown in FIG. 3. In this position, pads 26 are at ground level and end openings must be provided to allow'the upper ends of arms 20 to project out of floor box 14 as shown in FIG. 3.

Door mechanism 10 is provided tocover these end openings when the lift is elevated so that workmen will not step into the floor box when moving about and beneath the lift. Door mechanism 10 includes a pair of safety doors 32, with each door being pivotally mounted by a hinge 34 on the corresponding end of floor box 14. A crank 36 is provided for each door 32, respectively, each crank 36 having a first segment 38. for engaging the corresponding door 32, a second segment 40 rigid to and adjacent main door 28 and a third segment 42 interconnecting segments 38 and 40. Crank 36 is arranged so that, when the corresponding door 28 is horizontal (FIG. 3), segment 42 is substantially vertical and segment 38 overlies the lowermost edge of adjacent safety door 32 as the latter remains in a substantially inclined position. Thus, when door 28 moves into a raised position, crank 36 swings therewith and causes safety door 32 to move into a horizontal position as shown in FIG. 4. In this position, segment 38 supports the safety door from beneath and, since the main door 28 is held in its raised position by a pad (not shown) engaging cylinder 16, door 32 will not move inwardly under the weight of a workman standing thereon.

There is a crank 36 for each door 28, respectively. Thus, each safety door 32 will be elevated into its horizontal position of FIG. 4 in response to the upward swinging movement of a corresponding main door 28. Each segment 40 is welded or otherwise rigidly secured to the inner surface of the corresponding main door 28 at a location which permits the swinging movement of corresponding safety door 32 from an inclined position shown in FIG. 3 to the horizontal position shown in FIG. 4 as the main door 28 swings through an arc of approximately 65. Also, when each door 28 is in its raised position, segment 42 of the corresponding crank 36 will be in a slightly inclined position to assure that door 32 is horizontal. Thus, segment 40 will be slightly elevated with respect to segment 38 as shown in FIG. 4.

In use, lift 12 is initially in its lowest position with lift structure 18 within floor box 14 as shown in FIG. 3. Each pair of arms 24 will initially be in side-by-side relationship so that a vehicle can be driven into a location above the lift, following which arms 24 are moved into positions overlying the main frame of the vehicle.

The lift is then elevated in the conventional manner, during which time main doors 28 are opened by being first engaged by arms 20, following which cylinder 16 engages doors 28 to maintain the latter in their raised positions as shown in FIG. 4.

As doors 28 commence to open, cranks 36 on respective doors 28 pivot in a manner such that segments 38 are elevated. During upward movement of segments 38, doors 32 are swung from the inclined position shown in FIG. 3 into the horizontal positions shown in FIG. 4, at which locations, doors 32 are positively supported from beneath by cranks 36 and the doors will not swing downwardly because cylinder 16 prevents the downward swinging movement of doors 28. Thus, workmen can step onto doors 32 and be supported thereby without fear of falling into floor box 14.

When the lift descends, doors 32 remain in the horizontal positions thereof until doors 28 commence to swing downwardly. As doors 28 move downwardly, segments 38 of cranks 36 are lowered, pennitting the weight of doors 32 to move the latter downwardly and into their inclined positions of FIG. 3. Doors 32 will have moved downwardly before upper ends of arms enter the open top of lift floor box 14. In its lowest position, the lift will permit doors 28 to completely close the central part of the open top of floor box 14 and pads 26 will overlie and thereby cover the ends of the open top. The vehicle can then be driven away from the lift.

The present invention provides a safety door construction for a lift floor box which is automatically actuated when the lift is elevated and which is retracted when the lift is lowered. The invention is simple and rugged in construction and eliminates the need for springs and chains for actuating and supporting doors 32 when the lift is elevated. The invention also meets Governmental requirements for vehicle lifts of this type and can be adapted for use with existing drive through lifts without any substantial modification thereto.

In the claims:

1. In a vehicle lift of the type having a lift floor box provided with an open top and a pair of main doors swingably mounted on respective side margins of the floor box adjacent to said open top thereof for movement from respective horizontal positions closing corresponding side portions of said open top to respective operative positions opening said side portions, the combination with said main doors of a pair of end doors for respective ends of said open top, each end door having means thereon for pivotally mounting the same on a respective end margin of the floor box for free-swinging movement from a first location extending downwardly and toward the other end door to a second, generally horizontal location closing the corresponding end portion; and means carried by each main door, respectively, on the normally innermost surface thereof for moving a respective end door from its first location to its second location in response to the swinging movement of the main door from its horizontal position to its operative position, said moving means being operable to permit each end door to be lowered by gravity to its first location as the corresponding main door is returned to its horizontal position.

2. In a vehicle lift as set forth in claim 1, wherein said moving means comprises a crank rigidly secured to each main door, respectively, each crank being disposed to support the corresponding end door when the corresponding main door is in a-raised position.

3. In a vehicle lift as set forth in claim 2, wherein each crank has one end rigidly secured to the inner surface of a corresponding main door and an outer portion spaced from the main door for engaging and supporting the corresponding end door.

4. A vehicle lift as set forth in claim 3, wherein said outer portion is disposed for substantially point contact with the corresponding end door when the latter is in a first position and for making substantially surface engagement with the end door when the latter is in a second position.

5. In a vehicle lift having a vertically shiftable lift structure:

a lift floor box for housing said lift structure and having an open top, a side margin, and an end margin; a main door pivotally mounted on the side margin of the floor box for movement from a horizontal position covering a portion of the open top to a raised position uncovering said open top portion in response to the upward movement of said lift structure; and an end door pivotally mounted on the end margin of the floor box for free swinging movement from a lowered, inclined position within the floor box to a substantially horizontal position in substantially covering relationship to the corresponding end of the open top; and means carried by said main door for moving the end door from said lowered position to said horizontal position in response to the movement of the main door from said first position to said raised position thereof, said end door being movable by gravity from its horizontal position to its lowered position as said main door moves from its raised position to its horizontal position.

6. In a vehicle lift as set forth in claim 5, wherein said moving means comprises a bar secured to and extending outwardly from the inner surface of the main door, said bar having an outer portion for engaging said end door.

7. In a. vehicle lift as set forth in claim 6, wherein said outer portion engages an edge of the end door when the latter is in said lowered position and engages the inner surface of the end door when the latter is in the horizontal position.

8. In a vehicle lift as set forth in claim 5, wherein said moving means comprises a crank having a first segment extending toward the adjacent end margin of the floor box and a second segment secured to the first segment and extending toward the adjacent side margin of the lift floor box, the second segment being rigid to the corresponding main door and being swingable therewith with respect to the floor box.