US2757035A - Lifting forks - Google Patents

Description

July 31, 1956 o. J. BUEHLER LIFTING FORKS 3 Sheets-Sheet 1 Filed Dec. 30, 1953 INVENTOR Otto elBzl/eker 9W! ATTORNEYS July 31, 1956 o. J. BUEHLER LIFTING FORKS 3 Sheets-Sheet 2 Filed Dec. 30, 1953 INVENTOR. 0550 J B weld/er RNEYS July 31, 1956 o. J. BUEHLER 2,757,035

LIFTING FORKS Filed Dec. 50, 1953 3 Sheets-Sheet 5 O00 O00 O00 O00 O00 O00 INVENTOR. Ofifio J. B welder BY gwae ATTORAEYS United States Patent LIFTING FORKS ()tto J. Buehler, Dover, Ohio Application December 30, 1953, Serial No. 401,178

Claims. (Cl. 294-67) The invention relates to forks for lifting loaded pallets or palletized packages with a crane or other hoisting equipment provided with a cable, chain or other flexible suspension means.

Many articles, such as bricks and the like, are now being made up into palletized packages or units, or are loaded upon pallets for transportation. This requires the use of a fork lift truck for loading such units upon trucks or the like and removing the packages therefrom when they reach their destination. Such fork lift trucks are relatively expensive equipment and are not always available, particularly at the point of destination of the packaged goods.

The object of the present invention is to provide-a relatively inexpensive portable lifting fork which may be operated by a crane or similar hoisting means mounted upon a truck or trailer so that the same is available for loading the packages at the point of shipment and unloading them at the destination.

Another object is to provide such a device comprising a frame adapted to be placed upon the ground, or the floor of a truck, trailer or the like, adjacent to a palletized package or loaded pallet and having lifting forks movably mounted upon the frame and adapted to be inserted beneath the package in the manner of the forks of a fork lift truck.

A further object is to provide such a device in which the movable forks are connected to links pivotally suspended upon the frame, spring means being provided for normally holding the forks in retracted position.

A further object is to provide lifting forks of the character referred to, in which the movable forks are manually moved to operative position beneath the package, and as the package is lifted upon the forks the weight of the package resting upon the movable forks will pre vent their withdrawal.

A still further object is to provide such a device in which the spring means will automatically withdraw the movable forks from beneath the package when the pack.- age is lowered upon the floor of a truck, or upon the ground or other horizontal support.

Another object of the invention is to provide such a device in which the pivoted links carrying the movable forks are rigidly connected together so that both forks will be moved simultaneously to the extended or retracted position.

-'A further object is to provide a device of this character in which two chains connected to the rear portion of the frame and suspended from the hoisting device are provided for suspending the unloaded device with the forks retracted, and athird chain is adapted to be hooked to the forward portion of the frame for suspending the loaded fork, the third chain being adapted to unhook itself at the time the forks are withdrawn after the package has been delivered.

i The above objects together with others which will be apparent from the drawings and following description, or which may be later referred to, may be attained by con- "ice structing the improved lifting forks in the manner hereinafter described in detail and illustrated in the accompanying drawings, in which;

Fig. 1 is a perspective view of a lifting fork device embodying the invention, showing the movable forks in retracted or normal position;

Fig. 2 a vertical sectional view through the device with the forks in the normal or retracted position shown in Fig. 1;

Fig. 3 a perspective view showing the improved lifting fork device in position adjacent to a palletized package, preparatory to inserting the movable forks beneath the package;

Fig. 4 a perspective view of the device in position adjacent to the package showing the movable forks manually inserted beneath the package and the third hoisting chain being manually hooked to the frame of the device;

Fig. 5 a perspective view showing a palletized package suspended upon the improved lifting forks; and,

Fig. 6 an elevation of the improved lifting forks suspended from a hoisting equipment, showing a palletized package, partly in section, supported upon the movable forks.

Referring now more particularly to the embodiment of the invention illustrated in the drawings, in which similar numerals refer to similar parts throughout, the device includes a frame comprising a rectangular top portion formed of two spaced, inverted channel members 10 connected together near their rear ends by a bar 11 which may be welded or otherwise connected at opposite ends to the channel members, and connected at their front portions by an angle member 12 or the like, welded or otherwise connected at opposite ends to the forward end portions of the channels 10.

Eyes 13 or the like are attached to the rear ends of the inverted channels 10 for connection of the chains 14, the upper ends of which are attached to a ring 15 suspended by a cable or other flexible suspension means depending from a crane or other suitable hoisting equipment indicated at 17 which may be mounted upon a truck, trailer or other vehicle to be loaded and unloaded, as indicated generally at 18.

An upright hook 19 is attached to the central portion of theangle member 12 and adapted for engagement with the lower end of a third chain 20 suspended from the ring 15 of the hoisting equipment, as will be later described.

The frame also includes a pair of vertical, substantially U-shape frame members 21, one of which is connected to each of the horizontal channel members 10 at points spaced from the rear ends of the channel members. For this purpose the upper ends of the U-shape bars 21 may be welded ,or otherwise rigidly attached to the depending flanges 22 of the inverted channel members 10, as indicated at 23.

Angular truss members 24 may be connected to the U-shape frame members 21, at points spaced below their upper ends, and to the rear end portions of the channels 10, by welding or the like for the purpose of rigidity.

For the purpose of further reinforcing the frame structure-and rigidly attaching the U-shape frame members 21 together, a cross bar 25 is welded to the rear edges of the- U-shape members 21 at a point spaced above the lower ends thereof.

For the purpose of mounting the movable lift forks upon the frame, a spaced pair of depending links 26 is pivotally connected to the rear end of each inverted channel member 10, as indicated at 27. i

The movable forks are indicated generally at 28 and are in the form of relatively heavy, fiat steel bars, the

- rear-ends of which are preferably angled upward, as at 3 29, 'and:provi'ded with ears 3l)'f01 pivotal connection to thefends ofthe. links 26, as indicated at 3-1.

The forward ends of the lifting forks 28 are slidably mounted upon the lower bars 32 of the U-shape frame members 21. For-the purpose =of-eaus'ing both forks to move in unison, "a cross bar 36 is yielded, or otherwise rigidly connected, to all of the depending links 216 at points spaced above their lower ends.

For the purpose of normally holding the lifting forks 28 in retracted position, as shown in Figs. 1, 2 a-nd 3, springs 34 areprovided. The upper ends of the springs are connected to the forward ends ofthe V-shape ears 35, rigidly connected to the links 26 near the upper ends thereof as indicated at 36, and thelower ends of .the springs are provided with hooks 37 connected to the crossbar '25 upon the'verticalframe-members 23.

With the movable lifting forks 23 in retracted 'pjositiongas best shown in Fig. 2, the arms 35 rest upon the cross bar 38 which is connected at opposite endsto ,the strut-members 24, thus'prevcnting lllfiSPlillgS'fIOIIl withdrawing the forks 28 out of engagement with the 'U-shape frame members 21.

-With'the movable liftingforks 28 in retracted position, as shown in Fig. 2, the empty device may be suspended from the hoisting equipment by the two rear chains 14, the forward chain 2% being disconnected from the hook 19.

In the operation of the device, assuming that it is .desired to unload the truck or trailer 13, the device. is placed imposition upon the floor or bed of the truck ,or trailer adjacent to a palletized package 39 as shown in Fig. '2, with the movable forks '28 positioned at the openings 40 between the runners 41 at the bottom of the palletized package.

Then, as shown in Fig. 3, the workman places one foot against the cross bar 33 on the links 26, as indicated at P, and pushes forwardly upon the same inserting the movable forks 28 into the openings 40 in the'bottom of the package 39, as shown in Fig. 4.

Still holding his foot against the cross bar '33 so as to hold theforks in extended position beneath the package, the workman attaches the third chain 20 of the hoisting mechanism to the hook 19 at the forward end of. the upper frame of the device and starts the operation of the .crane or other hoisting mechanism.

,As .theforks 28 engage the underside ofthe package 39 and raise the same off of the floor, the weight of the package upon the forks will hold them in extended ,position. The crane is then operated to swing the suspended lifting ,fork device, with the package thereon, .over the side of the truck or trailer to lower the same toward the ground, as indicated in Figs. and 6.

v.As the fork lifting device and package thereon are loweredonto theground, ,and tension uponthe hoisting cable'16 is released, the weight of the package is thus removed from the movable forks 28, whereby the springs 34 will automatically withdraw theiforks to the normal or retracted position, and the third chain '20 willunhook itself, as shown in Figs. 1 and 2, so that'the liftingfork device may again be raised by the cable and positioned. on the truck or trailer for unloading another package. "In the "same manner palletized packages, or loaded pallets, maybepicked up from the ground and loaded onto a truck ortrailer.

From the above it will be seen that a simple,'inexpensive and easily operated portable lifting fork device is provided, which by meansof a crane 'or other hoisting mechanism may be easily and quickly operatedzfor loading palletized packages, or loaded pallets, onto a truck, or other vehicle, for transportation andunloading-the same from the vehicle at the point of destination, thus dispensing with-the necessity ;of keepingarelativelyrcostly lift truck available at both the loading -and unloadiug points.

In the-foregoing description, certain terms have been used for brevity, .olearness "and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact detailsof construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodimeats thereof, and the advantageous new and useful results obtained thereby; the new and useful constructions, and reasonable mechanical equivalents thereof obvious to those skilled in the art,-are set forthin the appended claims.

1 claim:

1. A portable lifting fork device for operation by a hoisting mechanism, said device comprising a frame, horizontally movable forks movably mounted in the frame, means for extending the forks into position beneath 'a load to be carried by the device, means whereby the suspended load upon the movable lifting'forks holdsthem in extended position, spring means for retracting the forks when the load is lowered onto a supporting surface, and flexible means suspending the frame from 'the hoisting mechanism.

2. A portable lifting fork device for operation "bya hoisting mechanism, said device comprising a substantially horizontal upper frame portion, vertical frame members depending from said upper frame portion, depending links pivotally connected to the upper frame portion,.mova ble lifting forks slidably mounted in said vertical frame members and pivotally connected to said'links, and spring means for normally holding said forks in retracted position.

3. A portable lifting fork device for operationby a hoisting mechanism, said device comprising a substantially horizontal upper frame portion, U-shape frame members depending from said upper frame portion, depending links pivotally connected to the upper .frame portion, movable lifting forks slidably mounted in said UrShape frame members and pivotally connected to said'links, and spring means for normally holding said forks in retracted position.

4. A portable lifting fork ,device for operation .by .a hoisting mechanism, said devicev comprising a substantially horizontal upper frameportion, U-shapeframe members depending from said upper frame portion, depending links pivotally connected to the upper frame ,portion, angular arms upon the upper portions of saidlinksmovablelifting forks ,slidably mounted in saidU-shapeframe members and pivotally connected to, said links,,-.and spring means connected to said angular arms and to the lower portions of said U-shape frame members for normally holding said forks in retracted position.

5. A portable lifting fork device for operationbya hoisting mechanism, said device comprising a,frame,.h01:izontally movable forks movablymountedin the frame, means for extending the forks into position beneath a load to be carried by the device, means whereby :the suspended load upon the movablelifting forksholds them inextended position, spring means for retracting ,the forks when the load is lowered onto a supporting-surface, means limiting; the retracting movement of the forkaandfiexible means suspending the frame from the hoisting mechanism.

References Citedin the file of:,this;patent UNITED STATES PATENTS .'ZO4,142 Straub Ju1y 8, .L9,Q2 802,815 Lau. ;Qct..24, 19.05 991,254 Weber ,May2, .1911 1,811,924 Fontaine ..,June31), 1931 3,495,658 Mosely "-2-"-.. Ian. 24, 195.0

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