US2419938A

US2419938A - Truck hoist mechanism

Info

Publication number: US2419938A
Application number: US620917A
Authority: US
Inventors: Edward J Abbe
Original assignee: Elwell Parker Electric Co
Current assignee: Elwell Parker Electric Co
Priority date: 1945-10-08
Filing date: 1945-10-08
Publication date: 1947-05-06
Anticipated expiration: 1964-05-06

Description

May a, 1947.-

E. J. ABBE TRUCK HOIST MECHANISM Filed 001;. 8, 1945 2 Sheets-Sheet l INVENTOR fan ,4? J 4555 Y 7, M 7 ATTORNEYS May 6, 1947 J ABBE I 2,419,938

TRUCK HOIST MECHANISM Filed Oct. 8, 1945 2 Sheets-Sheet 2 @u a zafg ATTORNEYS FIG. 5

Patented May 6, 1947 Edward J. Abbe, Cleveland Heights, Ohio, assignor to The Elwell-Parker Electric Company,

Cleveland, ()hio,

a corporation oi Ohio I Application October 8, 1945, Serial No. 620,917

(Cl..1&'7--9) 4 Claims.

The present invention relates to an industrial truck, and more particularly to a hoist mechanism for an industrial truck.

Industrial trucks have been provided having a vertically extending framework for guiding an elevator vertically, which elevator is raised and lowered by a hydraulically operated piston. The framework comprises two spaced upright members suitably tied together and which members receive therebetween a second framework adapted to telescope therewith so that the elevator could be raised relatively high although the framework would normally be compact. The

piston, during its upward stroke, would engage thetelescoped framework and raise it along with the elevator to provide an extended guide for the elevator. The framework would descend by gravity, and at times it would stick in the raised position after. the piston had receded downwardly, and this. wouldv result in improper operation of the elevator and there was also the danger of injury to the mechanism by the sudden release of the elevated framemember.

An object of the present invention, therefore, is to. provide mechanism for positively lowering the raised framework to prevent sticking thereof in the raised position- In carrying out the invention, I provide mechanism for latching the piston with the telescoped. frame member whereby the piston is positively connected with the framework throughout the range of movement of the framework. This mechanism. is adapted to release the piston from the telescoping frame member when the. frame reaches its lowermost position so that the piston may descend below the. point. at which it engages the frame.

Other objects and advantages of the invention will be apparent from the following description of the preferred form of the embodiment of the invention, reference being had to the accompanyingdrawings wherein.-

Fig- 1 shows an industrial truck including an elevator mechanism which embodies the invention;

, Fig- 2 is a view taken substantially on. line 2--'2 of Fig. 1;

Fig. 3 is.- a view in section, but on a larger scale, taken. substantially on line 3-3 of Fig. 2;

Fig. 4 is a view similar to that of Fig. 3, but showing the parts of the elevator mechanism in a different. position; and

Fig. 5.is.a view taken substantially on line 5-5 of Fig. 3.

Referring to the drawings, I have shown an industrial truck, illustrated generally at Ill, which is the type commonly used in factories, ware-i houses and the like for transporting material from one location to another. Although theirrvention may be used in connection with any suitable industrial type of industrial truck, the truck shown includes the running wheels l i: and power mechanism enclosed under the hood 2; The power mechanism may be either electric motors driven by batteries carried by the truck. or it may be a gasoline engine, for example;

At the forward end of the truck there is averticall-y extending framework, indicated generally at 35, which framework includes a main structure it and a structure it adapted to telescope in the main structure. This framework provides a guide for an elevator platform i8, which elevator is adapted to move vertically along the framework and to support loads to be carriedby the truck. The elevator i8 is adapted tobe elevated and lowered by a suitable hydraulic mechanism which includes a cylinder at and a piston rod 2t, which piston rod is actuated by a piston inthe cylinder. An oil pump and suitable valve mechanism, not shown, are provided whereby oil may be forced into either side of the piston for causing raising and lowering of thepiston rod. A head 22 is carried by the end of the piston rod 2i and a transversely extending axle 23- is carried by the head 22, which axle supports sprockets 2t mounted at opposite ends thereof. Twoc'hains 25 are threaded on the" respective sprockets, one end of the chains being secured to a cross-member 2? of the framework it by suitable clamp and bolt ar rangements shown at 28, and the opposite ends of the chains being similarly attached to'the ele'- vator [81' Thus, when the piston is raised and lowered the elevator !'8' will be raised and lowered correspondingly.

The frame structure It comprises two vertically extending members 38 and 3'! which are spaced apart and pivotally connected with the frame of the truck it in a suitable manner, not shown, and these members are tied together. by crossmembers Hand-32. The members'SG and-3E are preferably channel-shaped with the opensides thereof facing one another for receiving, respectively.two I-

beams

35 and 36 of the frame'structure l'T, which I-beams' form the structure i'l'. The beams 35 and 3b are secured together at their upper ends by an inverted channel member 37. Preferably, the beams 35 and Sdform a guide for rollers, not shown, attached to the elevator it, which rollers cooperate with the guide for moving the elevator in a vertical path. When" the piston rod 21- and frame-structure I 1 are in their lowermost position, the head 22 of the piston rod will be several inches below the cross-beam 31 of frame structure l1. Thus, the framework I is compact when the elevator is lowered so that the truck may be driven through relatively low clearance passages, but, when desired, the frame can be extended considerably for raising the load-carrying elevator It to a high loading or unloading point.

Preferably, the support structure |5 may be moved forwardly and rearwardly about its pivot by suitable mechanism, indicated generally at 40, for providing greater maneuverability of the loads carried by the elevator.

The structure thus far described is well known, and it may be fabricated according to standard practices. 7

Referring more particularly to Figs. 3, 4 and 5, I have provided means for locking and unlocking the head 22 of the piston rod 2| with the frame structure H as the piston rod engages and disengages the frame structure in its ascent and descent. This locking means is preferably formed by providing the head 22 of the piston rod 2| with an upwardly extending projection 4|, which projection has a flat top that is adapted to engage the underside of the inverted channel 31 when th piston rod is moved vertically, and a curved, downwardly facing surface 42 is formed in one side of the projection 4|, which surface is adapted to cooperate with a latch member 43 for locking the piston rod with the frame structure H.

The latch 43 is pivoted at 44 by trunnions formed thereon which extend through openings formed through spaced blocks 45 that are welded to the member 31. The lower portion of the latch 43 is formed to provide a surface that extends downwardly and inwardly, as indicated at 43, and the upper portion of the latch 43 is provided with a rounded portion 41 that is complementary to the surface 42 on the projection 4|. The latch 43 is urged clockwise about its pivot, as viewed in Figs. 3 and 4, by a spring 48, the ends of which spring react against a downwardly extending flange of the channel member 31 and the lower portion of the latch 43, as may be seen from the drawings. Thus, the latch 43 will normally tend to urge the upper portion 41 thereof beneath the surface 42 of the head 22 to thereby latch the piston rod 2| to the frame structure H in such a manner that the piston rod cannot move downwardly without also moving the frame structure.

Means are provided for operating the latch to release the piston rod 2| from latch 43 when the structure |1 reaches its lowermost position, and in the embodiment shown this means comprises a wedge-shaped cam member 50, welded or otherwise attached to the cross-member 32 of the frame structure It, which cam member has a sloping surface 5| in alignment with the inwardly and downwardly curved portion 46 of the latch 43. The cam 50 is so shaped and positioned that, as the frame structure H is lowered the surface 5| thereof is in alignment with the curved portion 46 of the latch 43 and the cam will cause the latch 43 to rotate counter-clockwise and thereby move the latch from beneath the surface 42 of the head 22. Thus, the piston rod is released from the frame structure at that point and it may continue further downward movement, as clearly illustrated in Fig. 3.

When the piston rod is moved vertically, it engages the channel 31, and as it raises the structure |1 upwardly, the sloping cam surface 5| permits the latch 43 to be rotated clockwise and 4 beneath the surface 42, as shown in Fig. 4, thereby latching the head 22 to the structure |1.

Preferably, I have provided guide blocks 55 welded to the channel member 31 for retaining the head 4| in a position to be engaged by the latch, and the lower corner of the blocks 55 are beveled as at 56 and the edge 51 of the head 4| is also beveled for guiding the head 4| into place. The latch '43 is recessed'for receiving one of the guide blocks 55.

It will be seen that by my invention I have provided an extremely simple and efficient mecha nism for assuring the proper lowering of the elevator guide structure so that positive operation of the structure may be had while allowing for full scope of movement of the elevator piston rod.

Although I have described but one form of the invention, it is to be understood that other forms may be adopted, all falling within the scope of the claims which follow.

I claim:

1. In an industrial truck, an upright support for guiding a platform vertically, said support including two sections, one slidable vertically relative to the other; a platform movable along said support; a, piston movable vertically and engageable with said one section for moving the latter and for raising said platform; means forming a latching connection between said piston and said one section whereby when the piston is being lowered said piston lowers said one section; and means for actuating the first mentioned means for releasing said piston and section when said section is lowered to a predetermined position.

2. In an industrial truck, an upright support carried by the truck; a second upright support telescoping with the first mentioned upright and movable longitudinally relative to said first mentioned upright; a load-receiving platform; means on said uprights and platform for guiding said platform vertically; means for raising said platform vertically including, a piston adapted to travel adjacent said second upright when said upright is moved longitudinally relative to the first mentioned upright; a latch member and a catch member, one of said members being mounted on said piston and the other of said members being mounted on said second upright, said latch being engageable with said catch for interlocking said piston and second uprightjand means for actuating said latch member when said piston and second upright move to a predetermined position for releasing said piston and second upright.

3. In an industrial truck, an upright support carried by the truck, a second upright support telescoping with the first mentioned upright and movable longitudinally relative to said first mentioned upright; a load-receiving platform; means on said uprights and platform for guiding said platform vertically; means for raising said platform vertically including, a piston adapted to travel adjacent said second upright when said upright is moved longitudinally relative to the first mentioned upright; a latch member and a catch member, one of said members being mounted on said piston and the other of said members being mounted on said second upright, said latch being engageable with said catch for interlocking said piston and second upright, and a cam member disposed on the first mentioned upright for engagement by said latch member whereby said latch member is disengaged from said catch when said second upright is moved to a predetermined position.

presenting a surface facing upwardly; a catch member carried by said piston, said catch presenting a surface facing downwardly for engagement with the surface of said latch; means resiliently urging said latch to a position for engagement with said clutch; and a cam engageable by said latch and adapted to rotate said latch out of engagement with said catch when the said second upright is lowered to a predetermined 10 position.

EDWARD J. ABBE.