Wheel Activator For Ambulatory Truck Loading Elevator

Abstract

A hydraulically powered, scissors type dock lift has levers at opposite sides of the frame and pivotally connected to the frame adjacent one end of the frame. Wheels are mounted on each of the levers. With the levers in one pivotal position, projections on the scissors contact the levers to depress the levers, pushing the wheels against the floor and thus raising the frame to be moved about on the wheels. With the levers in a second pivotal position, the projection on the scissors passes them without contact so that the frame remains on the floor.

Description

SUMMARY OF THE INVENTION

The present invention relates to a simple and inexpensive mount for the wheels of a dock lift or the like, which mount is power activated to force the wheels against the floor and thus raise the frame of the lift off the floor, the power activation using the power means already upon the lift.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dock lift embodying the present invention, with the lift resting on the floor and the platform in the raised position;

FIG. 2 is a perspective view of the same lift in lowered position and being readied for transport;

FIG. 3 is a fragmentary elevational view of the embodiment of the invention with the wheels not in use;

FIG. 4 is a fragmentary elevational view corresponding to FIG. 3 with the wheel ready for use, but not yet effective to raise the lift from the floor;

FIG. 5 is a similar elevational view showing the wheel in the position at which it raises the lift from the floor; and

FIG. 6 is a cross-sectional view as seen at line 6--6 of FIG. 4.

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 illustrated dock lift comprises a base or frame, generally 10, above which is a vertically movable platform, generally 11. The platform includes dock boards 12 which may be raised and lowered and a guard rail 13. Hydraulic power means, generally 14, connect the platform and frame to raise and lower the platform with respect to the frame. Also connecting the platform and frame at opposite sides thereof are scissors devices, generally 15. These scissors devices are identical, except that one is a left and the other is a right. Each includes a lever 16 pivotally connected at the lower end thereof to the base 10. At their upper ends the levers 16 have wheels, not shown, which run in tracks on the underside of the platform 11. Each scissors device includes a lever 17 which is pivotally connected at its top end to the underside of the platform. At the bottom ends of levers 17 are wheels 18 which run along an angle 19 forming a part of frame 10. These levers 16 and 17 are pivotally connected by pins 20. The scissors devices guide the vertical movement of the platform with respect to the frame.

At one end the frame has a bracket 21 having an opening 22 therein. Into this opening may be inserted the pin 23 of a dirigible wheel device, including wheels 24 and a handle 25. With the frame 10 resting on the floor, as illustrated in FIG. 1, the end thereof identified by the bracket 21 is raised by inserting the pin 23 into the opening and forcing down on handle 25 to approximately the FIG. 2 position, during which operation the dirigible wheel device cams the bracket upwardly to raise that end of the frame 10 off of the floor and support it on wheels 24. Wheel means are provided adjacent the other end of the frame to likewise raise that end off of the floor so that the dock lift may be moved from one place to another. However, when the dock lift is to be used all of the wheel means are moved to an inoperative position so that the frame 10 rests on the floor.

As thus far described in the preceding two paragraphs, the structure is conventional. The specific power means 14 illustrated in FIG. 1 is the subject of my copending application entitled Power Apparatus For Truck Loading Elevator, Ser. No. 331,641, filed Feb. 12, 1973. The novelty of the present invention resides in the wheel means at the other end of the frame from bracket 21 and in the actuation thereof using components otherwise available on the lift. The wheel means referred to are designated generally 26. There is one along each of angles 19 adjacent the end 27 of the frame 10.

Each of the wheel means comprises a pair of arms or levers 35 and 36. One end of each of the levers is welded to a tube 37. A bolt 38 extends through that end of the levers and through tube 37. This bolt is attached to the frame 10, forms a pivot pin for the levers and thus defines a pivotal axis.

At a distance from bolt 38, a second bolt 39 interconnects the levers. This bolt forms a shaft for wheel 40 that is journaled thereon and extends below the bottom edge of the lever when the lever and wheel are in the effective position illustrated in FIGS. 4 and 5. The lever 35 has an end 42 which projects beyond the corresponding end of lever 36. This projecting end has an upper face 43.

Adjacent the position of the wheel means 26 there are two inverted angles 45 and 46 welded to the angle 19 forming the side of the frame. The purpose of these inverted angles is to confine the top of the way along which the wheel 18 moves so as to prevent, at the locations of angles 45 and 46, wheel 18 from raising with respect to angle 19. A plate 47 steps out away from angle 46 and is welded thereto. This plate along with the adjacent side of angle 19 forms guide means for lever 35 and to this end defines a slot 48 of a size to receive end 42 of lever 35. This prevents the wheel means 26 from twisting away from the frame 10 when the wheel 40 is load bearing.

As the platform 11 is lowered, the end of the lever 17 to which wheel 18 is attached moves generally in the direction indicated by arrows 51 in FIGS. 3 and 4. As it does so, a projection or part 50 on the side of the lever 17 moves along a path with respect to the frame, three points of which path are pictured by the positions of the projection in FIGS. 3, 4 and 5. This projection extends over the frame side 19 as best seen in FIG. 6 to reach lever 35. With the wheel means 26 pivoted about bolt 38 toward the opposite end of the frame (the ineffective position of the wheel means pictured in full lines in FIG. 3), the movement of projection 50 along that path does not bring it into contact with the wheel means. However, if the wheel means is pivoted about bolt 38 to its effective position, which is illustrated in dash lines in FIG. 3, the movement of projection 50 along its path brings it into contact with the upper face 43 of the lever 35. The continued movement of the projection 50 in the direction indicated by arrow 51 after the projection has contacted lever 35, causes the projection to push downwardly on lever 35 because the movement of the lever 17 has a downward component as can be seen by comparing the position of the lever 17 in FIG. 5 with respect to its position in FIG. 4. The downward movement of lever 35 is transmitted to wheel 40. The result is that the wheel 40 is pressed against the floor causing the frame 10 to be raised off the floor to the position illustrated in FIG. 5.

Now, with the dirigible wheel device 23-25 in place, as illustrated in FIG. 2 (and the dock boards 12 raised), the lift may be transported to a new location as required. At that new location, the front wheel device 23-25 is removed in the conventional manner thus lowering that end of the frame 10 onto the floor. The power means 14 is then energized to temporarily raise the platform to an extent such that the projection 50 is out of the way, as illustrated in FIG. 3. During the initial part of this movement, the pressure on the wheel means 26 was relieved so that the corresponding end of the frame descended to the floor (i.e. the apparatus moved from the FIG. 5 to the FIG. 4 position). With the projection 50 in the FIG. 3 position, a wheel means 26 can easily be pivoted by a manual operation from the dash line position in that Figure to the full line position. With the wheel means 26 in the full line position of FIG. 3, the frame will remain on the floor no matter what elevational position is assumed by platform 11.

As compared to conventional devices, those having to use dock lifts will appreciate the fact that the wheel means 26 may be moved between the effective and ineffective positions with very little effort; plus the fact that no effort at all is required to further move the wheel means to raise the frame off the floor (i.e. move between the FIG. 4 and FIG. 5 positions) since this is done solely as a power operation. Substantially no cost has been added to the lift, since a wheel means must be provided in any event if the lift is to be ambulatory and because the power operation is obtained from structure already present on the lift.

Claims

I claim:

1. In an apparatus such as an ambulatory dock lift or the like for use on a floor, said lift comprising a frame having two sides opposite each other, a vertically moving platform, scissors means adjacent each of said sides, interconnecting the frame and platform and guiding the platform above the frame for vertical movement with respect to the frame, power means interconnecting the frame and platform for providing said vertical movement of the platform, wheel means at spaced points on the frame and movable downwardly between an inoperative position at which the frame rests on the floor and an operative position at which the wheel means support the frame above the floor, the improvement comprising:

each of said scissors means having a part that moves in a given path adjacent the respective side of the frame as the platform moves up and down; and

a mounting for each of said wheel means comprising:

a lever adjacent a respective one of said sides of the frame and having a distal end and a proximal end, said proximal end being connected to said one side for pivotal movement about a generally horizontal axis whereby when the lever is in an effective position at which it is positioned at one side of the vertical plane including said axis a first surface portion of the lever is facing up and a second surface portion is facing down and when the lever is in an ineffective position at which it is positioned at the other side of the vertical plane including said axis said first surface portion is facing down and said second surface portion is facing up, said wheel means projecting beyond said second surface portion of the lever, said lever being positioned along said one frame side so that when said lever is in said effective position said first surface portion is in said path so that as said platform descends said part bears on said first surface portion to push the lever down so that the wheel means supports the apparatus from the floor, and when said lever is in said ineffective position it is spaced from said path so that as said platform descends said frame remains resting on the floor.

2. In an apparatus as set forth in claim 1, wherein said lever has a projection at its distal end, said frame including guide means positioned at each side of said projection when said lever is in said effective position to hold the lever at right angles to said axis.

3. In an apparatus as set forth in claim 1, wherein at a respective side said scissors means and said lever are separated by said respective side, said part projecting over the top of said respective side.