Low-rise vehicle lift for use over a pit

A low-rise vehicle lift for use above a pit having side rails rising above a working surface. The vehicle lift comprises a pair of spaced apart base units coupled to corresponding vehicle support units through a lifting means. The lifting means can be a set of legs in either a parallel or scissor configuration. The base units are typically placed parallel to one another straddling the pit and side rails, the base units and vehicle support units coupled together by an adjustment bar. The adjustment bar is attached to the vehicle support units such that a space is provided for allowing the side rails to freely move within when the lift is in a lowered position.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to hydraulically powered lifts for vehicles,
 and in particular for vehicle lifts that are used on a solid surface
 having a pit, the lift straddling the pit.
 2. Description of the Prior Art
 Vehicle and automotive repair establishments often must be able to raise
 the vehicle, such as a car, truck, etc. The vehicle must be raised to
 various levels depending upon the task to be performed by the service
 personnel. In many applications, such as vehicle body repair, tire
 rotation, front end alignment, brake servicing, as well as new and used
 vehicle preparation and reconditioning, the desired height may be limited,
 thus necessitating the use of a "low-rise" surface mounted lift as
 distinguished from below ground buried lifting cylinders. Such low-rise
 lifts are typically bolted to the surface of the floor of a service bay in
 a garage, and some can be mounted on wheels for mobility.
 The problem with many of these prior art low-rise lifts is that they are
 not made to fit newer garages designed to have a pit. In many new vehicle
 repair and service establishments, a working surface such as a concrete
 surface is placed above an open space or pit that it typically 2.5 to 3
 feet in width and several feet in length. Service personnel can then go
 into the pit and service a vehicle driven and parked over the pit, the two
 wheels on either side of the vehicle straddling the pit.
 In most garages with pits, the pit is lined on its upper edge adjoining the
 working surface with a rail. rail is typically "L" shaped in
 cross-section, having one edge (or afoot safety guard) extending and
 rising from the working surface from 2-4 inches, and the other edge
 forming a holding surface for such implements as an oil pan. This rising
 edge of the rail creates a discontinuity in the working surface of the
 garage wherein presently used low-rise lifts will not operate properly.
 The use of a low-rise lift under such circumstances necessitates, at a
 minimum, having to cut the rail edge that rises from the surface. Since
 the rail is typically hardened steel or iron, this is difficult and time
 consuming as well as unsafe.
 Further, most low-rise lifts have cross-members joining the two lift
 platforms, the cross members further hampering its use over a pit where
 access from below the vehicle in the pit is partially blocked. This can
 also create a safety problem for the workers below who can injure
 themselves by hitting their heads on a stationary cross member. Also, the
 prior art cross-members were not adjustable to accommodate pits or
 vehicles of various widths. Since most low-rise lifts to date are not made
 for use in a pit, there is a need for an improved lift for such use. The
 lifts that do not employ cross members joining the two spaced apart
 platforms are unsafe and unreliable. As the lift wears, the two sides
 begin to lift independently at different rates since no cross member is
 present to join the sides. The vehicle being lifted is lifted at an angle
 which could result in the vehicle falling off the lift. The lack of a
 cross member decreases cross lead stability.
 SUMMARY OF THE INVENTION
 One object of the present invention is to provide a low-rise vehicle lift
 for use on a working surface with a pit.
 Another object of the present invention is to provide a vehicle lift
 wherein the distance between the tire-lifts is adjustable to fit various
 sized pits and vehicles.
 Yet another object of the present invention it to provide a simplified
 low-rise lift as compared to the prior art which has fewer parts and which
 is easier to assemble.
 Yet another object of the present invention is improve the safety of
 vehicle lifts by having an adjustment bar that can be moved away to avoid
 workers below in a pit, and a safety support arm that can be adjusted to
 within 1 inch, thus precluding accidental slippage of the lift from a
 raised to a lowered position.
 Another object of the invention is to provide a vehicle lift with cross
 members which add stability and reliability and yet which do not require
 cutting away the pit guard or raise the lift above the pit guard by
 building up the floor on the surface that supports the lift.
 The objects of the present invention are achieved by providing a vehicle
 lift for use above a pit having side rails rising above a working surface.
 The vehicle lift comprises a pair of spaced apart base units that make
 contact with the working surface, each base unit having a corresponding
 vehicle support unit. A lifting means for moving the vehicle support unit
 between a lowered position and a raised position relative to said
 corresponding base units is provided. The lifting means can be either
 parallel or scissor configured legs that hold the vehicle support and the
 vehicle parked thereupon. The base units are placed parallel to one
 another and separated by a distance from one another sufficient to clear a
 pit with side rails, the corresponding vehicle support units being coupled
 to one another by an adjustment bar. In order to facilitate its use over a
 pit having side rails, the adjustment bar clears the pit side rails when
 the vehicle support unit is in the lowered position.
 Additional objects, features and advantages will be apparent in the written
 description which follows.

DETAILED DESCRIPTION OF THE INVENTION
 Vehicle lift 11 is described first with reference to FIG. 1. A pair of
 spaced apart base units 13 make contact with working surface 23. The base
 units 13 are typically affixed to the working surface 23 by an appropriate
 fastening means such as a bolt, adhesive, etc. Working surface 23 is
 typically a hard surface made from concrete or similar material. Each base
 unit has a corresponding vehicle support unit 15. One base unit 13 and one
 vehicle support unit 15 and their associated elements form tire-lifts 101
 and 103. It is advantageous to have two tire-lifts 101 and 103 to lift at
 least the front end or back end of a typical 4-wheeled vehicle, the front
 wheels of the vehicle being driven onto the vehicle support units 15. The
 lifts 101 and 103 can be designed to fit both front and back tires
 simultaneously, thus lifting the entire car. Hereinafter, the vehicle lift
 11 will be described by referring to only one set (101 or 103) of
 tire-lifts. It is to be understood that both tire-lifts 101 and 103 are
 substantially mirror-images of one another, and the vehicle lift 11 refers
 to both tire-lifts.
 The vehicle support unit is provided with ramp 33 shown in FIG. 1. This
 allows a vehicle to be more easily driven onto the vehicle support unit
 15. Also, safety bar 27 is pivotally coupled to the vehicle support unit
 15 to allow an arcuate movement parallel to the axis of the base unit. The
 safety bar 27 extends downward to make frictional contact with stopblock
 31, the stopblock having a plurality of spaced detents 107, shown in more
 detail in FIGS. 6 and 7. The detents are spaced about 1 inch apart from
 one another. Most prior art vehicle lifts have safety bars and stopblocks
 with detents spaced about 4 inches apart. The stopblock 31 of the present
 invention creates a safer lift by preventing the vehicle support units 15
 from falling as in prior art devices.
 Thus, even with slippage in the present invention, the safety bar will
 catch onto a detent that is closely spaced together, preventing a great
 amount of force from being created in the slipping of the bar. The handle
 29 allows the service personnel to easily adjust the position of the
 safety bar 27 from one detent 107 to another.
 Referring back to FIG. 1, a lifting means is provided for moving the
 vehicle support unit 15 between a lowered position 83 (FIG. 2A) and a
 raised position 85 (FIG. 2C). FIG. 1 shows the vehicle lift 11 in a raised
 position. The lifting means in the present embodiment is a set of parallel
 legs 17 placed between the base unit 13 and vehicle support unit 15. The
 legs 17 are attached to the base unit 13 with hinge 21 and at the vehicle
 support unit 15 with hinge 19 (not shown). It is to be understood that,
 although four legs are shown on each of the tire-lifts 101 and 103, three,
 five, or any other number of legs is suitable. Further, the legs can be in
 a scissor configuration as disclosed in U.S. Pat. No. 5,322,143.
 A hydraulic piston 35 having hydraulic line 37 coming from an external
 control unit (not shown) controls the movement of the vehicle support unit
 15 relative to the base unit 13. Thus, the piston being operatively
 coupled to the base unit 13 and corresponding vehicle support unit 15
 raises the support unit 15 when in the extended position (also shown in
 FIG. 2C), and lowers the support unit 15 when in the distended position.
 The external control unit typically controls both hydraulic pistons 35
 simultaneously, thus evenly lifting and lowering the vehicle. A suitable
 control unit can be obtained commercially from a number of sources and
 will be familiar to those skilled in the relevant arts.
 The function of the vehicle lift 11 is shown with reference to FIGS. 2A
 through 2C. The vehicle lift 11 is in a lowered position 83 in FIG. 2A,
 wherein the vehicle support unit 15 is about 2-4 inches above the base
 unit 13, the base unit being substantially flat against the working
 surface 23. Ramps 33 and 119 facilitate a vehicle being driven upon the
 support unit 15. Once a vehicle's front or back two wheels are centered
 upon the support unit 15, the hydraulic piston 35 is activated from its
 retracted position towards its extended position, moving the vehicle
 support unit 15 as shown by the arrows in FIG. 2B. Once in its desired
 position as shown in FIG. 2C, the safety support arm 27 can be engaged
 with a detent 107 of the stopblock 31. This locks the vehicle support unit
 15 in position, keeping the vehicle parked upon the support unit 15 and
 safely in position while service personnel can work in the pit 41 below.
 The pair of base units 13 are typically placed parallel and spaced from one
 another so as to straddle the pit 41 cut into the working surface 23.
 Typically, the pit 41 will have side rails 25 on either side of the pit.
 The side rail is typically "L" shaped in cross-section as shown in FIG. 5,
 having a vertical edge 45 and horizontal edge 47. The base units 13 are
 separated by a distance from one another sufficient to clear, and
 preferably to just clear the side rails of the pit so as to be immediately
 adjacent to the side rails 25.
 Referring back to FIG. 1, the vehicle lift 11 has an adjustment bar 39. The
 spaced apart tire-lifts 101 and 103 are coupled together by adjustment bar
 39, the bar typically straddling pit 41. Referring now to FIGS. 3 and 4,
 the adjustment bar 39 has a first adjustment arm 51 and a second
 adjustment arm 61, each arm having a proximal ends 87 and 97,
 respectively, and a distal ends 95 and 105, respectively. The proximal
 ends of the adjustment arms 51 and 61 are attached to support flange 49,
 the support flange 49 being coupled to the vehicle support unit 15 by an
 appropriate fastening means such as a bolt, or soldering, etc. The
 adjustment arms 51 and 61 are attached through hollow hinge 57, a bolt,
 toggle pin, or other suitable fastening means passing through the hinge
 and thus allowing the adjustment bars 51 and 61 to swivel on a pivot axis
 81 and 91. The adjustment arms 51 and 61 are attached by using at least
 one fastening element 63 such as a bolt, etc. FIG. 3 shows the swivel
 movement of each adjustment bar, the bars designed to swing in arcuate
 paths B and C from a retracted position to an extended position which is
 perpendicular to the axis of the vertical support unit 15.
 When in the extended position, the adjustment arms come into contact as
 shown in FIG. 3. This allows a pin 63 or other suitable fastening means to
 be placed through aligned holes 53 located on each of the arms 51 and 61.
 Once secured, the vehicle support units 15 are secured to one another and
 are laterally stabilized.
 Referring to FIG. 5, the vehicle lift 11 in the lowered position 83 is
 shown in detail, specifically highlighting the area of the lift 11 that
 comes into closest contact with the side rails 25 of the pit 41. Side rail
 25 is attached to the edge formed by working surface 23 and the side wall
 109 of pit 41. The side rail has a vertical edge 45 and horizontal edge
 47, the vertical edge extending a distance 111 from the axis of the
 working surface 23. This creates an discontinuity in the working surface
 axis near the pit edge. In order to use vehicle lifts of the prior art,
 this discontinuity, the edge 111, must be cut. The vehicle lift 11 of the
 present invention allows the vehicle lift 11 clearance of the vertical
 edge 45, while the adjustment bar laterally stabilizes the lift.
 Support flange 49 has coupled to it the adjustment arm 51, the arm having
 hollow hinge 57 to allow the passage of a fastening means 55 such as a
 bolt and nut to pass through the hinge 57. Such an attachment allows the
 adjustment arm 51 to swing freely as described supra. The support flange
 49 is located far enough away from the working surface 23 when the vehicle
 lift 11 is in the lowered position 83 as to define the distance 117, the
 distance 117 being at least enough to allow the edge 111 of the side rail
 25 to freely enter. Likewise, the support flange 49 extends a distance 113
 from the vehicle support unit 15, the distance 113 being at least enough
 to allow attachment of the hollow hinge 57 and to leave a space 115
 between the hinge 57 and vehicle support unit 15. Thus, the space created
 by edges 115 and 117 is at least enough to allow the edge 111 of the side
 rail to fit freely within. The flange 49 is typically welded on the
 vehicle support unit 15, and can be attached to increase or decrease the
 distance 115.
 The vehicle lift 11 is assembled in a garage having a working surface 23
 and over a pit 41 by first placing a pair of base units 13 on the working
 surface in a spaced apart manner so as to be on either side of the pit.
 The base units 13 are typically parallel and in tandem with one another. A
 vehicle support unit 15 is provided with each base unit 13, the two being
 coupled by a lifting means such as legs 17. The legs are attached by
 hinges which allow the movement of the vehicle support unit 15 to a raised
 position or a lowered position. Next, the adjustment arms 51 and 61 are
 swung from their retracted position against their respective vehicle
 support units 15 to an extended position perpendicular to the axis of the
 vehicle support units 15. The base and vehicle support units (tire-lifts
 101 and 103) are then slightly adjusted to substantially align at least
 one hole 53 from each of adjustment arm 51 and 61. A toggle pin 63 or
 other fastening means is placed through the aligned holes to secure the
 arms to one another, thus forming the adjustment bar which stabilizes the
 vehicle lift 11.
 The present invention offers several advantages over the prior art. Due to
 the greater use of pits in garages for service personnel to work beneath a
 vehicle, and the various widths that pits are designed, it has become
 increasingly advantageous to design a low-rise vehicle lift for such an
 environment. The present vehicle lift of the invention meets the needs of
 many current garages and auto service centers.
 The vehicle lift of the present invention offers the advantage of allowing
 the railings typically located on the pit edge to remain intact. This
 allows the full use of the railing.
 The adjustment bar can be retracted when not in use, adding to the safety
 of mechanics using the associated pit.
 The safety bar is safer, sturdier than the prior art designs and is
 adjustable every one inch.
 The distance between the tire-lifts of the present invention can be readily
 adjusted to fit various pit sizes or vehicle widths. The adjustment bar of
 the invention is simple and easy to use and offers little hindrance to a
 service worker located in the pit beneath the car and lift.
 While the invention has been shown in only one of its forms, it is not thus
 limited but is susceptible to various changes and modifications without
 departing from the spirit thereof.