Lift Device For Small Equipment

Abstract

A compact, inexpensive lift device, capable of elevating small equipment (such as a snowmobile) to a convenient working height for servicing or repair, includes a mobile base frame, a lift frame carrying an equipment support platform, a linkage arrangement pivotally connecting the lift frame to the base frame, a hydraulic ram for raising and lowering the lift frame, and a ramp hinged to one end of the lift frame. Hydraulic and electrical supply units, as well as electrical controls, are mounted on the base frame, making the device an integral, self-contained assembly which can be easily moved to and operated at convenient locations. When in a lowered position, the support platform is upwardly inclined to provide clearance for the supply units and to facilitate movement of equipment onto the platform.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No. 257,766, filed May 30, 1972 and now abandoned.

Description

BACKGROUND OF THE INVENTION

This invention relates to lift devices and, more particularly, to a lift device capable of elevating small equipment, such as snowmobiles and the like, to a working height convenient for servicing or repair.

Many types of small equipment, particularly motorized equipment such as snowmobiles, snowblowers, garden tractors, lawnmowers, etc., are difficult to service and repair because of their low profiles. It is often necessary for personnel to assume awkward and uncomfortable positions, while bending over such equipment to perform certain tasks.

In addition to being very bulky and expensive, most available vehicle lifts cannot be conveniently used to elevate small equipment of this type to more comfortable working positions. These lifts frequently require a permanent or semi-permanent installation, either because of the massive support structures used or service connections required for power, control, etc. Consequently they cannot be easily moved about to more convenient points of use. Also, it is often advantageous to be able to raise a portion of the equipment being serviced to facilitate access or to remove heavy components, such as an engine, while the equipment is positioned at a convenient working height.

SUMMARY OF THE INVENTION

A primary object of this invention is to provide a compact, inexpensive lift device for elevating relatively small equipment to convenient work positions.

Another object of this invention is to provide such a device which can be easily moved to different points of use.

According to this invention, a lift device is provided which includes a base frame, a lift frame carrying a support platform on which the equipment is supported, a linkage arrangement pivotally connecting the lift frame to the base frame, motive means for raising and lowering the lift frame, and a ramp means hinged to one end of the lift frame. The power source and control means for the lift frame motive means are supported on the base frame beneath the support platform, making the device an integral, self-contained assembly which can be moved to and operated at any convenient locations without requiring any separate disassembly and/or installation steps. The base frame is preferably provided with wheel means, so the device is completely mobile and can be easily moved to convenient locations. The ramp means, which can be swung down when the lift table has been elevated to a convenient working height, acts as a safety to prevent the lift table from becoming accidentally lowered.

It is also preferred to provide an overhead crane assembly which is supported on the base frame and can be used to elevate a portion of the equipment or to remove heavy components therefrom, while the equipment is supported on the platform at a convenient working height.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a lifting device embodying various features of the invention shown in the elevated position with a snowmobile supported thereon.

FIG. 2 is a perspective view of the lifting device illustrated in FIG. 1, shown in the collapsed position with a riding lawn mower being moved up the ramp onto the platform.

FIG. 3 is a fragmentary, side elevational view of the mechanism for locking the ramp into the raised position.

FIG. 4 is a side elevation view of the linkage arrangement incorporated in the device illustrated in FIG. 1, shown in the fully raised and the fully lowered positions.

FIG. 5 is a side elevation view of an alternate embodiment of the linkage arrangement, shown in the fully raised and fully lowered positions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The lift device of this invention includes a base frame 10, a lift frame 12 carrying equipment support platform 14, a linkage arrangement 16 pivotally connecting lift frame 12 to base frame 10, a hydraulic ram 18 for raising and lowering lift frame 12, and a ramp 23 hinged at 21 to one end of lift frame 12. Base frame 10 has a pair of longitudinal members 20 which are connected together by a cross member 22 and a plate member 24 mounted on the base frame. Lift frame 12 has a pair of longitudinal rails 26 which are connected together by cross members (not shown).

For purposes of description, the term "front" and "rear" will be used to identify the portion of the device corresponding to the position which the equipment, such as a snowmobile 28 (FIG. 1) or a riding lawn mower 29 (FIG. 2), is supported on platform 14. Thus, as viewed in FIG. 1, the left side is the front end and the right side is the rear end. As viewed in FIG. 2, the right side is the front end and the left side is the rear end.

Referring to FIGS. 1-4, linkage arrangement 16 includes a pair of laterally spaced, front legs 30 and a pair of laterally spaced rear legs 32. The upper end of each of the front legs 30 is pivotally connected to lift frame 12 by a pin or bolt 34 extending through a pair of spaced, downwardly depending ears 36 which are mounted on the front portion of respective rails 26. The lower end of each of the fron legs 30 is pivotally connected to base frame 10 by a pin or bolt 38 extending through a pair of spaced, upstanding ears 40 which are mounted on the front portion of respective longitudinal members 20. The upper end of each of the rear legs 32 is pivotally connected to lift frame 12 by a pin or bolt 42 extending through a pair of spaced, downwardly depending ears 44 which are mounted on the rear end of respective rails 26. The lower end of each of the rear legs 32 is pivotally connected to base frame 12 by a pin or bolt 46 extending through a pair of spaced ears 48 which are mounted to and extend from the rear end of respective longitudinal members 20.

The opposite ends of hydraulic ram 18, which is a conventional single action hydraulic piston/cylinder assembly, are pivotally connected to base frame cross member 22 and 50 and to front lift frame cross member at 52, respectively. Extension of piston rod 54 raises lift frame 12 and retraction of piston rod 54 lowers the lift frame. Pressurized hydraulic fluid is supplied to the ram cylinder via hose 56 from a conventional electrically-powered hydraulic pump/reservoir assembly 58 supported on plate member 24. Electrical power for the hydraulic pump of assembly 56 is provided by an electrical storage battery 60 supported on plate 24. The operation of the electrical motor and, hence operation of hydraulic ram 18, is controlled by a conventional control means, such as by a push button assembly (not shown). Lift table 12 can be adjustably elevated between the fully lowered or collapsed position shown in FIG. 2 and the fully elevated position shown in FIG. 1 by the operation of hydraulic ram 18.

In accordance with the invention, linkage arrangement 16 is arranged such that platform 14 is substantially parallel when lift frame 12 is in a fully elevated position (FIG. 1) and assumes an upwardly inclined position when lift frame 12 is in a fully lowered or collapsed position (FIG. 2). With this arrangement, the rear end of platform 14 can be lowered to a position adjacent the floor to facilitate movement of equipment, such as a riding lawn mower 29, up ramp 23 and onto the platform while the front portion of the platform remains sufficiently raised or elevated to prevent it from striking battery 60 and hydraulic pump/reservoir assembly 58. Since all the actuating means for raising and lowering the work platform 14 are located beneath the platform, they do not obstruct access to the equipment supported on the platform. Thus, the platform can be elevated to the most convenient working height and workmen have substantially unrestricted access to the equipment being repaired or serviced from all sides of the platform. Also, by placing all the actuating means beneath the platform there is provided a compact, self-contained unit which can easily be moved to different locations.

While various linkage arrangements can be used, in the preferred construction illustrated in FIGS. 1-4, front legs 30 are shorter than rear legs 32 and the lower pivot axis for the front legs (i.e., bolts 38) is located above the lower pivot axis for the rear legs (i.e., bolts 46). Also, the longitudinal dimension between the upper pivot axis for the front and rear legs (i.e., bolts 34 and 42, respectively) is greater than the longitudinal dimension between the lower pivot axes for the front and rear legs (i.e., bolts 38 and 46, respectively). That is, the front and rear legs are non-parallel, with the rear legs being at a slightly larger angle to the vertical than the front legs when platform 14 is in the fully raised position (See FIG. 4). When lift frame 12 is lowered to a fully lowered or collapsed position, the platform assumes an upwardly inclined position (best shown by dashed lines in FIG. 4).

FIG. 5 illustrates an alternate arrangement for the linkage arrangement 16a in which the front legs 30a are parallel to the rear legs 32a. Also, front legs 30a are longer than rear legs 32a and the lower pivot axis for front legs 30a (i.e., bolts 38a) is located below the lower pivot axis for rear legs 32a (i.e., bolts 46a). Otherwise, the device is constructed in the same manner as described above, and the work platform is substantially horizontal when the lift frame 12 is in the fully raised position and assumes an upwardly inclined position when lift frame is in the fully lowered position (as shown by dashed lines in FIG. 5).

Extending from the rear legs are arms 62 which are adapted to rest on the floor to support the rear legs when lift frame 12 is completely lowered to a collapsed position.

Ramp 23 is arranged so it also acts as a safety to prevent the lift table from being accidently lowered, in the event of a hydraulic system failure, inadvertent actuation of the control means, etc. As shown in FIGS. 1, 3 and 4 ramp 23 swings down to a vertical position when the lift frame is in an elevated position. If the lift table is accidentally lowered for some reason, the ramp becomes jammed against the floor and prevents further lowering. The length of ramp 23 preferably corresponds to a vertical height most convenient for working on the equipment being serviced. When a lift table is elevated to this height, the ramp prevents any lowering of the lift table.

During normal operation, ramp 23 is manually raised to permit the lift table to be lowered. As shown in FIG. 3, ramp 23 can be locked into the raised position by L-shaped bar 64, which is slidably mounted in bushings 66 mounted to the underside of platform 14. Bar 64 is moved to an extended position to support the ramp in the raised position. When the lift table is elevated, bar 64 is moved back to a retracted position, either prior to or after raising lift frame 12, so that the ramp can swing down to a safety position. Bar 64 is provided with a limit stop 68, such as a cotter pin extending through the bar, which engages the forward bushing during retraction and prevents the bar from being removed from the bushings.

While at a convenient working position on platform 14, the rear end of snowmobile 28 can be raised to gain ready access to the underside of track section 70 by crane assembly 72, as shown in FIG. 1. Crane assembly 72 includes an overhead boom 74 pivotally mounted to vertical post 76, which in turn is suitably supported on base frame 12, and a hand operated winch 78 mounted on vertical post 76. Cable 80, carrying a hook 82 on the outer end, is mounted on boom 74 and wound onto the drum of winch 78 in a conventional manner, so that the hook can be raised and lowered to desired positions by rotation of hand crank 84.

Casters 86, mounted on base frame 10, permit the lift device to be easily moved to various locations where it can be most conveniently used. Casters 86 are preferably provided with conventional braking means to prevent the lift device from moving, after it has been appropriately positioned for the servicing or repair task to be performed.

From the above detailed description, it can be seen that this invention provides a simple, inexpensive lift device which is very compact, self-contained and can be easily moved to various locations where it can be most conveniently used to service various types of small equipment. Also, the integral crane means provides the capability of raising the equipment to facilitate access or removal of heavy components, such as an engine, while the equipment is positioned on the platform at a convenient working height.

Claims

I claim:

1. A lift device for elevating small equipment to convenient working positions comprising:

a generally horizontally disposed base frame supported on a floor and having longitudinally spaced front and rear portions;

a vertically movable lift frame located above said base frame and carrying a platform for supporting the equipment, said lift frame and said platform having longitudinally spaced front and rear portions;

a fluid actuated ram pivotally connected at one end to said base frame and pivotally connected at the other end to said lift frame and located beneath said platform for moving said lift frame vertically relative to said base frame between a fully raised position and a fully lowered position where the equipment can be moved from the floor onto said platform;

means supported on said base frame and located beneath said platform for supplying a controlled flow of actuating fluid to said ram; and

means pivotally connecting said lift frame to said base frame for said vertical movement in response to the actuation of said ram, said last-mentioned means including

a first pair of laterally spaced front legs having lower ends which are pivotally connected to the front portion of said base frame for relative pivotal movement about a first pivot axis and upper ends which are pivotally connected to the front portion of said lift frame, and

a pair of laterally spaced rear legs having lower ends which are pivotally connected to the rear portion of said base frame for relative pivotal movement about a second axis and having upper ends which are pivotally connected to the rear portion of said lift frame, said first and second pivot axes being located at different elevations and said legs being angularly related such that, when said lift frame is in the fully raised position, said platform is substantially horizontal and, when said lift platform is in the fully lowered position, the rear portion of said platform is adjacent the floor and said platform is upwardly inclined towards the front portion to provide sufficient vertical clearance between said platform and said base frame for accommodating said ram and said means for supplying a controlled flow of actuating fluid to said ram.

2. A lift device according to claim 1 wherein said base frame is supported on wheel means so that the device is mobile as a unit.

3. A lift device according to claim 1 including

a ram swingably mounted on the rear portion of said lift frame and engageable with the floor when said lift frame is in a lowered position for affording movement of the equipment from the floor onto said platform, said ramp being swingable to a generally vertical position when said lift frame is moved to a fully raised position and having a length sufficient to act as a safety to prevent said lift frame from being accidently lowered below an elevation convenient for working on equipment supported on said platform.

4. A lift device according to claim 3 including a bar mounted on said platform and movable into engagement with said ramp for selectively locking said ramp in a raised position generally coplanar with said platform.

5. A lift device according to claim 1 wherein said means for supplying a controlled flow includes

an electrically operated hydraulic pump and reservoir assembly for supplying pressurized hydraulic fluid to said ram; and

an electrical storage battery for supplying electrical power to said assembly.

6. A lift device according to claim 5 wherein

said front legs are shorter than said rear legs, said first pivot axis is located above said second pivot axis and said front and rear legs are non-parallel.

7. A lift device according to claim 5 wherein

said front legs are longer than said rear legs, said first pivot axis is located below said second pivot axis, and said front and rear legs are parallel.