US3515299A - Industrial truck with self actuated load lifting attachment - Google Patents

Description

June 2, 1970 E. s. ESSER 3,515,299

INDUSTRIAL TRUCK WITH SELF-ACTUATED LOAD LIFTING' ATTACHMENT Filed July 22, 1968 INVENTOR.

ERNST S ESSER ATTORNEY.

United States Patent U.S. Cl. 214-350 9 Claims ABSTRACT OF THE DISCLOSURE An industrial truck for transporting dies or the like, equipped with a cam that is moved by a die as the die moves endwise toward the truck. A surface of the cam contacts an undersurface of the die for lifting the die as the cam is moved by the die. Therefore, the cam is selfactuated for lifting the die.

This invention relates to an industrial truck, and more particularly an industrial truck of that type adapted to transport heavy dies.

Industrial lift trucks designed for the handling of heavy dies are well known in the art. In general, a truck of the particular class has a relatively low platform of considerable area. While the platform is relatively low, it is generally positioned above the level of a die that is to be moved. Since a die may weigh 20,000-60,000 pounds, it is readily understandable that the lifting of the die from a relatively low position to the level of the platform of the industrial truck, presents a considerable problem because of low press bed height.

In one form of industrial truck manufactured by the assignee of this application, Eaton Yale & Towne Inc., power actuated level mechanism is mounted at one end of the frame of the truck immediately below the platform. The lever mechanism includes lifting levers equipped with rollers that are adapted to move under a die that is to be loaded on the platform of the truck, and rams are provided for swinging the levers so as to move the rollers upwardly, bringing the die to the level of the platform.

In a construction of this class, it is obvious that the area and length of the load platform of the industrial truck is naturally decreased to the degree necessary for the mounting of the levers, since the levers must project beyond the load accepting surface of the platform. Also, of course, means must be provided for supplying hydraulic fluid to the rams, to mount the rams on the truck, and to control the rams. In such a hydraulic system, horizontal movement of the die has to be coordinated with lifting of die, otherwise the die can slip from the lift-roller.

It must also be considered that while the prior art construction I have outlined will operate effectively to lift a die so that it may be moved onto the plateform of a truck, additional means must be provided for so moving the die onto the platform. These means may take the place of a cable actuated by a winch, or may also take the form of fingers movable in grooves formed in the surface of the platform of the trucks. In prior art trucks, such fingers are utilized for manipulating a die, and for moving a die off a truck platform for deposit on a machine, etc. Fingers of the particular class are also frequently used for actuating a cable for moving a die, all as is well known to those skilled in this art.

The invention that I have conceived and which I describe in this application, utilizes what I term a cam mechanism mounted on a truck and actuated merely through movement of the die toward the truck platform, for actually lifting the die so that it may be deposited 'ice on the surface of the truck platform. As a feature of the invention, I utilize a cam having at least two arms, one arm to be applied under the die, while another arm is contacted by an end surface of the die. Movement of the die against the cam contacted by its end surface, will bring about rotation of the cam on its mounting means, and the surface that is under the die will lift the die. In other words, the mechanism is self-actuated by the pushing or pulling of the die relatively to the truck. Since in the old form of mechanism eariler discussed and well known in the art, it is necessary also to pull or push the die relatively to the truck, it is obvious that I eliminate in my construction, an entire relatively costly power operating mechanism, While yet achieving all of the results inherent in the mechanism of the prior art.

As a particular feature of my invention, I prefer to use a cam having a pair of crossed arms, the cam being rotatably mounted in a horizontal axis where the arms meet and cross. The ends of the crossed arms are equipped with rollers for contacting the end surface of the load and also the undersurface of the load.

As a particular feature of my invention, the cam is adapted to be controlled by mechanism-that may take the form of a brake or a locking pin inserted so as to prevent rotation. When the brake or other means is locked so as to hold the cam in a particular position, one surface of the cam positioned beyond the normal extent of the platform, forms an efiective extension of the platform. Therefore, through my invention, the effective length of the platform is considerably longer than the effective length of the platform of prior art trucks of this type, even through I eliminate the power mechanism and other parts of the prior art. Therefore, it will be appreciated that I achieve an extraordinarily valuable result while still eliminating mechanism that is essential in prior art constructions.

As a still further feature of the invention inherent in the construction, the brake mechanism to which I have alluded, may be utilized to control the speed of rotation of the cam. Therefore, the cam may be utilized effectively to permit removal of a heavy die since, as the die strikes the cam, the cam may be rotated very slowly so as in turn to lower the die very slowly to a lowered position. Therefore, I am able to achieve the results of the prior art without the requirement of the power mechanism of the prior art. While this last feature of my concept may be achieved through controlling the die movement by a cable, those skilled in the art will appreciate that it is almost impossible to pay out a cable at the slow rate necessary to lower a die. Utilizing my invention, it is possible to control and move the cam in extremely small increments to lower a die most effectively.

I have thus outlined rather broadly the more important features of my invention in order that the detailed description thereof that follows may be better understood, and in order that my contribution to the art may be better appreciated. There are, of course, additional features of my invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which my disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of my invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of my invention, in order to prevent the appropriation of my invention by those skilled in the art.

Referring now to the drawings, FIG. 1 is an elevation of a typical truck to which my invention may be applied. FIG. 2 is a plan view of that end of the truck of FIG. 1

3 on which is mounted the cam of my invention. FIG. 3 is a view similar to FIG. 1 showing the die as it first contacts the cam, and illustrating how the cam forms an extension, in effect, of the platform of the truck with the die supported thereby. FIG. 4 illustrates a modified form of the invention.

Referring now more particularly to the drawings, reference numeral indicates generally an industrial truck of the class to which my invention may be applied. The truck is adapted to move over a floor or ground surface on Wheels 11 and 12. The operator stands on a platform at '13 and controls the movement of the truck through suitable controls that are not shown, and steers through a steering wheel 14. Wheels 11 are the traction wheels, and they are driven by an electric motor or by an internal combustion engine. In the truck illustrated, the wheels 11 are driven by an electric motor powered by a battery housed in the casing 24.

The cam of my invention, in its preferred form, is well illustrated in FIGS. 1, 2 and 3. Because of the size of the truck and the loads to be handled, I actually use three identical cams, each of which is designated generally by reference numeral 15. Each cam is preferably fabricated from a heavy casting in the form of crossed arms. Thus, one of the arms is designated by reference numeral 16, and the other arm by reference numeral 17. Where the arms cross one another, there is a bore for housing a shaft 18. The shaft 18 is itself adapted for rotation in four longitudinally positioned plates 19, 20, 21 and 22 integral with the truck main frame. In that form of my invention in which a brake is used for controlling the rotation of the three earns 15, each of the cams is preferably keyed to the shaft 18 at 23 so that, the three cams rotate together with the shaft 18, and are controlled as will be indicated presently.

For contacting a die D or similar load, each of the arms 16, 17 has at its opposed ends a freely rotating roller, the roller on the upper end of the arm 16 in FIG. 3 being designated by reference numeral 25, while the lower roller on the end of the arm 17 is designated by reference numeral 26. In the position of the cam shown in FIGS. 1-3, the roller 26 is the lifting roller, while the roller 25 is the roller that is pushed by movement of the die I), all was will be explained presently.

At one end of the shaft 18, as well seen in FIG. 2, a brake 30 is provided for braking the shaft 18 and for locking it in a particular rotated position. The brake is shown controlled by a rod 31, but the brake may be a hydraulic brake, and in that event, reference numeral 31 indicates conventional tubing for transmitting fluid under pressure to the brake 30. In any event, through the utilization of a standard form of braking mechanism, the shaft 18 may be held against rotation, or controlled in its rotation so that it will rotate very slowly, moving with it the three cams 15. In describing the invention, I shall refer to but the one cam 11 shown in FIGS. 1 and 3.

Obviously, if the cam illustrated in FIG. 3 is held locked, the roller 25 will lie at the level of the upper surface 35 of the platform of the truck, forming an effective extension of the platform. While there will be some slight space between the end of the platform and the roller 25, this space will not be of consequence, and the roller 25 may be utilized to support a load just as effectively as were the load platform surface 35 continued to the roller 25.

In FIG. 3 a die D is shown in contact with the roller 25 but not with the roller 26. This contact is brought about generally through movement of the truck against the die. Let us now assume that the die is pulled toward the truck. This movement of the die may take place in several ways. Thus, in FIG. 1 the truck is shown equipped with a winch W adapted to wind a cable 36. This cable 36 may be utilized to pull the die D toward the truck in a manner well known by those skilled in the art. On the other hand, the die may be moved forwardly relatively to the truck by movement of the truck in the direction of the arrow 37 in FIG. 3 as the die is held against movement.

In any event, with the die supported on skids or dunnage 38 below the level of surface 35 of the truck platform, any movement of the die toward the truck, will cause the roller 26 to move to its position of FIG. 1 where it is directly under the die D. Obviously, continued rotation of the roller 25 and the arm 16 in a counterclockwise direction in FIG. 1 will cause the roller 26 to exert continued upward pressure against the bottom surface of the end of the die and to lift that end of the die upwardly and away from the skid 38. In FIG. 1 it will be noted that roller 25 has its upper surface somewhat above the upper surface 35 of the platform of the truck. Obviously the roller 26 will also reach the position of the roller 25 while lying under the bottom of the die. Therefore, the end surface of the die will actually reach a position just above the surface 35 of the truck prior to moving to its final resting position of FIG. 3 shown in dash and dotted lines where the roller 26 will lie in the position of the roller 25, and will form an effective extension of the upper surface 35 of the platform. The roller 26 may be held with cam 15 in this position by such means as brake 30.

In my truck, I may utilize die actuating fingers such as shown by reference numeral 50, which ride in grooves 51 formed in the platform surface 35. Such die handling fingers are well known in the art, and may be used to move cables such as the cable 36, or to physically contact a die to push it off the load or to swing it on the surface 35.

It will be quite obvious that a reverse movement of the cam 15 is necessary to bring about a lowering of the end of a die from surface 35. In that event, the particular roller 25 or 26 lying under the die will prevent its swift movement downwardly, if that roller is prevented from swift movement by the utilization of the brake 30. Therefore, by applying the brake 30, very slow rotation of the cam 15 in a lowering direction, is made possible.

In FIG. 4 I show a simplified form of cam mechanism designated generally by reference numeral 60 and comprising a generally L-shaped member having a lift surface at 61 and a push surface at 62, the cam being mounted on the shaft 18 where the two arms, in effect, of the cam 60 cross. Essentially, cam 60 will operate as does cam 15.

It is to be understood that the generally L-shaped cam 60, while operating very well in accordance with the principles of my invention, may require initial positioning or repositioning prior to lifting or lowering a die. That is, it is necessary for the legs of the L to be appropriately positioned with respect to the die. Whereas, a cam mechanism having three or more legs generally symmetrically spaced about a central axis will automatically assume the proper position for lifting or lowering a die as required.

I do believe that the very considerable contribution of my invention will now be understood by those skilled in the art.

I claim:

1. In an industrial truck, a main frame having a load platform formed with a surface for receiving a load, a lifting cam, means mounting said lifting cam for pre determined movement on said main frame, a lift roller and a push roller rotatably mounted on said cam and both projecting outwardly relatively to one edge of said platform in one position of said cam whereby said lift roller may be applied under the end of a load as said push roller is applied against a surface of said load facing said push roller, whereby the application of force to move said load relative to said platform will, through the push roller on said cam, move said cam so that the lift roller will lift the load relatively to the main frame and the platform.

2. In the combination of claim 1, the feature that the cam is pivoted relatively to the main frame on a horizontal axis below the surface of the platform on which the load is to be deposited.

3. In the combination of claim 1, the feature that at least part of the cam is in the form of an L-shaped lever with said rollers located at the ends of the arms forming the L, the lever being pivoted to the platform at the juncture of the arms.

4. In the combination of claim 1, the feature that the cam is in the form of a plurality of intersecting arms rotatably mounted on the main frame where the arms intersect, and said rollers are on the ends of said arms.

5. In the combination of claim 1, means for controlling the speed of movement of the cam under pressure of a load to facilitate use of the cam lift roller for lowering slowly the end of a load.

6. In the combination of claim 1, means for holding said cam at a position thereof in which a surface of said cam lies at the level of the load receiving roller surface of the platform to form, in effect, a part of the load receiving surface of the platform.

7. In an industrial truck, a main frame having a load platform formed with a surface for receiving a load, a lifting cam mounted on said frame for rotation about an axis located below said load receiving surface, said lifting cam comprising a lift surface for engaging one face of the load and a push surface for engaging another face of the load, said lift surface being located below said axis and said push surface being located above said axis when said cam is in an initial load engaging position, said lift and push surfaces being radially spaced from said axis and having an angularly spaced relationship to one another whereby a force exerted by the load on said push surface will create a moment about said axis and cause said lift surface to raise said load to a position approximate the load receiving surface.

8. In the combination of claim 7, means for controlling the speed of movement of the cam under a load to facilitate use of the cam lift surface for lowering slowly the end of a load being moved relatively to said platform.

9. In the combination of claim 7, said cam further comprising a plurality of intersecting arms with said axis at the intersection of said arms and a shaft passing along said axis and rotatably mounted with respect to said load platform, said push and said lift surfaces comprising rollers rotatably mounted at the ends of said arms and including means for controlling the speed of cam movement comprising means locking said cam to said shaft and a brake mounted on said shaft to allow retardation of rotation of said shaft under load.

References Cited UNITED STATES PATENTS 1,139,243 5/1915 Warner 1878.49 2,492,364 12/1949 Levy 214-354 2,541,523 2/1951 Lang.

ALBERT J. MAKAY, Primary Examiner U.S. Cl. X.R. 214-84; 2542

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