Automotive jack

• US 5,096,160 A
• Filed: 08/21/1991
• Issued: 03/17/1992
• Est. Priority Date: 02/27/1989
• Status: Expired due to Term

• Current Assignee: Snap-On Incorporated
• Original Assignee: FMC Corporation
• Inventors: Spillyards, Judson D., Hill, Ronald L., Calico, Gregory M.
• Primary Examiner(s): SWANN, JUDY J
• Application Number:
  US07/750,743
• Time in Patent Office: 209 Days
• Field of Search: 254/2 R, 254/2 B, 254/2 C, 254/93 HP, 254/122, 254/124
• US Class Current: 254/93.0HP
• CPC Class Codes: B66F 7/065 Scissor linkages, i.e. X-configuration
• CPC Class Codes: B66F 7/08 hydraulically or pneumatically operated
• CPC Class Codes: B66F 7/085 pneumatically operated

Abstract

A scissor jack of the type which is mountable on and usable in conjunction with a conventional automotive vehicle lift to permit a selected axle of the vehicle to be elevated relative to the lift. The invention provides a gravity activated locking mechanism which includes a plurality of lock keys of different widths. The keys fall individually into a lock position as the jack rises incrementally in height, to prevent unintended lowering of the jack at any height or any time during the lifting process.

Claims

1. A scissor jack comprising:

a base with an upper surface lying generally in a horizontal plane and an end wall extending upwardly from said upper surface;

a top lying generally in a horizontal plane and which may be moved vertically between a raised position and a lowered position;

means for moving said top upward and downward between said raised and lowered positions;

first and second scissor assemblies, each of said scissor assemblies having a first and second scissor arm each of said scissor arms having a top end, a base end, and a center portion said first and second scissor arms pivotally connected to each other at said center portions, said base end of said first arm rotatably attached to said base and said top end of said second arm rotatably attached to said top;

top attachment means for attaching said first arm top ends to said top to allow only rotational and horizontal displacement of said first arm top ends;

a cylindrical roller having a horizontal, longitudinal roller axis extending from a first roller end to a second roller end, said first and second roller ends rotatably attached to said base ends of said second arms of said first and second scissor assemblies, respectively, and said roller supported by said upper surface of said base such that said roller rolls along a path normal to said roller axis from a first position adjacent said end wall when said top is in the lowered position to a second position away from said end wall when said top is elevated to said raised position;

an elongate latch arm, said latch arm having a first end pivotally attached to said upper surface of said base at a pivot point more distant from said end wall than said second roller position, said latch arm extending along a longitudinal axis generally perpendicular to said roller axis toward said end wall to a distal end, said pivot point and said distal end separated by a distance less than the distance between said pivot point and said end wall, said latch arm further comprising a latch head extending downwardly a distance greater than a diameter of said roller to a latch head lower edge and extending back along said latch arm axis from said distal end toward said first end over a latch head width such that, when said roller is adjacent to said end wall said latch head lower edge rests upon and is supported by said roller and when said roller is separated from said end wall by a distance greater than said latch head width, said latch head drops to a position in which said latch head lower edge is supported by said upper surface of said base and said latch head is interposed between said end wall and said roller.

2. The invention according to claim 1 further comprising;

release means to selectively rotate said latch arms to raise said heads from between said end wall and said roller.

3. The invention according to claim 2, wherein said release means comprises;

a bar attached to a first latch arm with a first latch head of narrow width and extending under a second latch arm with a latch head of greater width than said narrow width; and

an air cylinder having a piston capable of contacting said bar.

4. A scissor jack having a base, an end wall extending upward from the base, a raisable top and means for moving the top upwardly and downwardly between raised and lowered positions comprising;

first and second inner scissor arms each pivotally attached at a base end to said base;

first and second outer scissor arms each pivotally attached at a top end to said top;

First pivotable attachment means for pivotally attaching said first inner arm and said first outer arm in abutting relation;

second pivotally attachment means for pivotally attaching said second inner arm and said second outer arm in abutting relation;

first and second upper rollers rotatably mounted on a top end of said first and second inner arm, respectively, and supporting said top;

a cylindrical lower roller having a first and second roller end each lying on a longitudinal roller axis, said first and second roller end rotatably connected to a lower end of said first and second outer arm, respectively, and supported by said base such that said lower roller moves from a first position adjacent the end wall when said top is in the lowered position to a second position a distance further from the end wall than said first position when said top is moved to the raised position;

a latch arm pivotally connected to said base at a base end and extending toward the end wall and above said lower roller to a distal end adjacent the end wall;

a latch head extending downward from said distal end to a lower edge and;

said latch head having a latch head width smaller than said distance such that said lower edge is supported by said lower roller when said lower roller is in said first position and drops to be supported by said base when said lower roller is in said second position.

5. A scissor jack as in claim 4, further comprising:

a plurality of latch arms, each of said latch arms having a latch head of unique latch head width, such that, as said top is moved upward from said lowered to said raised position, latch heads successively drop between said lower roller and the end wall.

6. The invention according to claim 5 including an uneven numbered plurality of latch arms separated into a forward and a rearward group of equal number, one latch head in each group having a width equal to the width of one latch head in the other group.

7. The invention according to claim 6 further comprising;

a spacer bar connected to the inner ones of the latch arms in each of said groups to insure the integrity of and separation between said groups.

8. The invention according to claim 7 wherein heads of narrowest width are on outer latch arms and latch heads of the wider width are on inner latch arms.

9. The invention according to claim 8, further comprising;

a release bar secured to said outer latch arms and extending under the other latch arms.

10. The invention according to claim 9 further comprising an air cylinder having a piston capable, upon extension, of contacting said release bar to raise all of said latch arms.

11. The invention according to claim 10 and further comprising a tool tray including:

a U-shaped tubular member having both ends attached, a wall member attached to and extending downward a floor member attached to said wall member intermediate its height wherein said u-shaped tubular member may also serve as a handle.

12. The invention according to claim 11 and further comprising,

a first valve for directing air pressure to said air cylinder mounted on said wall member below said floor member.

13. The invention according to claim 12 and further comprising;

an air bag connected between said base and said top;

a second valve for directing air pressure to said air bag for elevation of said top mounted on said wall member below said floor member;

a third valve means connected to exhaust air from said air bag mounted on said wall member below said floor member; and

said first and third valve being separated a distance sufficient to require two hands for operation thereof.