US2610751A - Lift truck - Google Patents

Description

Sept. 16, 1952 a. BEVAN 1 LIFT TRUCK Filed May 12, 194? :2 Sl-lEETS-SHLET 1 fla 2 SHEETS-SHEET 2 G. BEVAN LIFT TRUCK Sept. 16, 1952 Flled May 12 1947 Patented Sept. 16

4* UNITED STATES PATENT E.

LIFT TRUCK:

George Bevan, Norfolk, Va., assignor to Freight Handling Corporation, a corporation of Vii Application May 12,1947, Serial no. 747,3sr ,4 oiaims. (01. 214- 4 13) The present invention relates to lift trucks and particularly to mobile trucks of, the so called forklift type in which the platform upon which the load to" be transported is placed has :a fork-like appearance owing to the fact that it comprises a plurality of elongated parallel members extending horizontally from a supporting base, these members generally tapering outward- 1y from'the base and thus resembling tines.

Many lift trucks of this type are now in use'for' :1

the transportation of goods through relatively short distances, particularly from place to place within. ,afactory building, for movement of freight from factories into freightcars or from freight cars into warehouses, and elsewhere. The loads which these trucks are called upon to handle vary greatly in character. Raw materials in bales and materials in self-supporting'contai'ners, such, as wooden boxes, must, of course, be frequently and likewise granular and pulverulent materials in paper or cloth sacks, these envelopes being non-self-supporting and being readily broken or torn. Thus the truck must be of such character as toh'ave the capacity to rea ceive,'sa'fely transport, and deliver sacks of flour as well" aslcontainers which" will not break even when 'subjectedto rough handling.

Certain commodities may be placed, for the purpose of transportation .and ultimate delivery, directly upon"th e"tines or elongated'load suppbrting' elements of the conventional fork lift truck. Hogsh'ea'ds off'tob'a'cco and large bales and boxesof'othergoods' may with advantage be handled in this manner. Other commodities,

such for instance as sacks of granular orpulverulent. material, may be transported with greater .safetyupon continuous flat platforms which provide uniform support. To provide such support- :ingsur'faces it has therefore been conventional practice for those employing lift trucks in the transportation, of goods in sacks or bags'to' em ploy what are known as pallets. A pallet comprises aload'supporting floor adapted to receive,

fcr'inst'ance, from three to'six flour sacks formto' thirty such sacks, together with means to space this lead carrying floor a short distance ing a bottomlayer, with others piled thereon in layerformation'to form a stack of from fifteen fromthe ground/This spacing of 'the'pallet floorwpermits the tines of a fork lift truck to be moved into position under the pallet floor so that the pallet may beengaged, raised, and transported, together with its superposed load.. The

pallet, lat the'p'oint of loaddischarge, is generally g lowered by the fork lift onto a supporting surpallet'to the loadcarrying portion of a fork' ty'pe goods; against movement while the supporting facefstill carrying its previously placed load, andmay be lost to its owner, particularly if goods in sacks or bags are being loaded into a freight car for transportation to a distant point. T prevent loss of pallets in this manner it has been proposed that the lift truck beprovided with a pusher by means of which a load may be held stationary as the truck is retracted and that the pallet'and lift a truck be providedlwith mutually interlocking means to insure that the pallet will not be sep- I arated from the lift truck but will simply be withdrawn from beneath the load. 1

In accordance with the present invention a load supporting pallet of .novel character is provided, this'being substituted for the usual pallet having spaced upper and lower floors. Improved means are provided for detachably securing this lift truck. As a feature of this part of myinvention, the means for securing the pallet to the, fork truckare preferably formed so that they Y are" actuated into and out of securing relation" merely through manipulation of the truck bodily relatively to the pallet.

'As a further feature of my invention the load supporting pallet takes the form of a steel plate of desired configuration, and this steel plate. may have legsorf casters thereunder whereby one edge may be supportedseveral inches above a' fioor while the other edge is against the floor. Thus, this pallet if placed upon a horizontal surface will assume an inclined positionunless that edge which is normally against the surface is supported upon blocks or by other members. It is the function of the legs or casters to support one edgeof the pallet at such a height that the usual forks of a lift truck may readily be in! serted beneath the pallet and to permit that manipulation between the truck and pane-trequiredto engage and'disengage the truck and pallet. J

As previously stated, the improved 'loadsupporting pallet i to be permanently retained at one location and, is preferably held against discharge'with its load when the pusher of the associated truck is operated to .hold apile of pallet is being withdrawn-from beneath the pile. For that reason a special means isprovided for detachably securing the palletto the elevatingplatform or forks of the truck. This means permits the pallet to be readily securedin operative I position and to be as readily detached, while at the same time is of such character as torequire load, or deposited upon a 3 no modification or alteration in the structure of the truck itself, which is important. Thus I prefer t secure detachable the pallet in position to rest upon the forks so that the weight of the pallet and its load is transmitted to the forks in the usual manner and I provide, as a securing means, one or more members that may be designated attachment members, extending between the elevating platform of the truck and the pallet. By providing means such as described that may be readily added to a lift truck not intended for such operation, the operator of a lift truck can convert the truck quickly and easily, and without the use of securing bolts, or without modifying the structure of the truck in any way, for the transportation of goods of widely different characteristics. It will be appreciated by on skilled in the art that, without departure from the invention, various types of devices for detachably connecting the continuous surface type of load carrying platform to the lift truck may be devised, although that form to which brief reference has been made, and which will hereinafter be described in detail, is preferred.

The improved pallet is preferably fabricated of metal and may be quite thin, whereas the con: ventional pallet has a thickness of five or six inches. When a conventional pallet of five or six inches in thickness is withdrawn from beneath a pile of goods, such goods necessarily drop this distance of five or six inches onto a supporting floor, or onto a pile which has been'previously deposited, causing bags to burst as'they,

pass over the edge of the pallet and also causing the bags or cartons to lose pile formation. When myimproved skid is employed no such drop occurs upon discharge of goods and all breakage and loss of pile formation is avoided.

The novel pallet furthermore makes possible the practice of an improved method which results in the realization of substantial economies in the loading and transportation of goods. It also becomes possible to fully load freight cars without additional labor. The use of large numbers of pallets is avoided, the improvement making it possible to transfer a given quantity of goods by means of a lift truck 'and' several pallets, and with the expenditure of a relatively small amount of manual labor Whereas, when conventional palletsare employed, a substantial number are required and'the amount of labor requiredsubstantially increased. Numerous other advantages will be apparent.

In the accompanying drawings:

Figure l is a perspective view of the forward portion of a lift truck of the fork type, showing the novel pallet in chain lines and the elements for detachably connecting this pallet to the truck in full lines;

Figure 2 is a section on line 22 of Figure 1;

Figure 3 is a section on line 3-3 of Figure 1;

Figure 4 is a perspective view of one of the attachment elements;

Figure 5 is a similar view of a modified form of attachment element;

Figure 6 is a partial section taken on line 6.8 of Figure 2;

Figure 7 is a section on line T-l of Figure 6 Figure 8 is a perspective view of a portion 01' the underside of my pallet, showing an attached hook member which forms a portion of the means for separably connecting this pallet to the truck Figure 9 shows in side elevation one of the elongated tines of the fork lift, showing also, in process of assembly therewith, one of the members by means of which the separable connection of the pallet to the truck may be effected;

Figure 10 is a section on line Ill-i 0 of Figure 9;

Figure 11 shows in side elevation a pallet resting with one end on a floor or base while the other end is supported by wood blocks, a portion of the front end of a conventional fork lift truck being illustrated, with the tines of the fork under the platform;

Figure 12 is a view showing the elevating platform of the truck in a higher position, the load carried by the platform being supported directly above a similar load and ready to be discharged; and

Figure 13 is a view of the parts of Fig. 12 with the pusher of the truck, actuated and the truck with its attached pallet simultaneously retracted toeflect the discharge of the load from the pallet upon the top of a previously deposited load.

As previously explained, the invention is primarily concerned with trucks of the fork lift type. Such trucks are well known and are in common use and, inasmuch as the details of construction of the truck itself are unimportant insofar as the present invention is concerned, these details are not illustrated and will not be described.

In the rather diagrammatic Figures 11, 12 and 13 a portion of the truck frame'is indicated at F, one of the front wheels at W, the mast at M,

pusher frame actuating mechanismH." The mast f M is provided, adjacent its'lower end, with at tached hook members oneof which is indicated at I t e e mbe ng and b n s bported by a horizontally extending rod ll carried by the truck frame, The mast may be rocked about rod ll through a limited angle, either forwardly from the vertical position 'in' which it is shown in Figure 11 to an inclined position such as that of Figure 12, or rearwardly through a small angle, as desired, and held in any such position to which it maybe moved, by any suitable mechanism. The carriageC is supported for movement vertically along the mast and some suitable means for. accomplishing this will be utilized. Qne mechanism for effecting tilting of the mast and vertical reciprocation of the carriage C is, for instance, shown in Patent 2299,44,,

issued to E. W. Weaver. Any other such means concerned.

The means H for advancing and retracting the pusher frame P may consist principaily of two cylinders l2, secured to Opposite sides of the car; riage C respectively, each having a spring retracted telescopic piston l3 upon the outer ends of which the pusher frame P is mounted. A conduit for conducting fluid under pressure to the cylinder shown is indicated at I4 and it will be understood that by the use of known devices the operator may control the flow of fluid under pressure to and away from the cylinder and hence the operation of the hydraulic means H and the movements of the pusher frame F. l

The forks or tines l5 selected for illustration include two or more (in this case four) generally parallel horizontally extending outwardly tapering elements, the heavier ends of these elements being suitably attached in a rigid manner to the carriage or elevator C so that the tines together constitute a generally horizontally disposed load supporting means. which may be liftedv and with the truck. As previously explained, the

forks iii are highly useful in the .transportation of certain types of loads, without the application of a pallet, and are also well suited for engaging, lifting and transporting the conventional pallet.

The present invention contemplates the provision of a pallet generally indicated at S in the drawings, and which is preferably fabricated of metal and in plate form, relatively thin but substantially inflexible when. loaded. It is rectangular and is provided at two adjacent corners with legs or supports, such as indicated at I6, solid legs being used if desired, but these supports preferably comprisingcastors. The nature of the supports is not important exceptthat they should function to allowthe forks to moveunder the floor of the pallet when the pallet rests with one end against theground and withiits other end raised by the supports. In Figure '11 the load carrying forks l5 of the truck are shown inserted under the platform, the end thereof not provided with permanent supports being mounted upon supporting'blocks B so that the platform is substantiallyhorizontal. This holding of the pallet floor horizontal is helpful in the loading thereof but is not essential. It is well to understand also that the supports l6 may be entirely eliminated and the pallet floor mounted on blocksthereby to permit entry thereunder of the truck forks.

Intermediate the castors i6, and Welded or otherwise rigidly attached to the pallet, is an L-' shaped catch I8 which projects downwardly (shown upside down in Fig, 8) and has area-rwardly projecting terminal end portion, this catch comprising one element of a means for separably' connecting the 'pallet to the truck. The pallet is preferably not directly attached to any portion of the truck but to an intermediate means comprising two atachment members 20, one of whichis shown in its entirety in Figure 4 of the drawings.

To those skilled in the arteach member will appear to resemble what is known as an extension fork, adapted to be slipped onto or off.

of a fork or tine 15 at will. and which, when positioned as shown in Figures 1 and 2, is locked to the tine. Actually, the functioning parts of members 20', to be set forth below, may be made integral with forks l5 and said attachments discarded. Locking and unlocking of members 20 to the forks is effected without the aid of tools or separate securing devices. Thus the flat plate with ears 200 which are connected by a cross bar 22. The space defined by this cross bar 22, the adjacent parallel end edge of the plate, and the flanges 20a and 20b is a tine receiving space,

shown most clearly in Figure 9. Assembly of member 20 with element I5 is readily effected by inclining the member 20 as shown in Figures 9 and 10, advancing it axially of element l 5 so that the free end of the element passes through the aperture provided for its reception, and thereafter moving member 20 longitudinally of element l5 until its leading end has been advanced as far as maybe, whereupon it is lowered so as to lie directiy upon the uppersurface of the member 15 below it, the cross or looking bar 22 passing.

around, in such movement, the curved end of thetine I5 to a position in rear ofthe vertically extending continuation of .this element, which'is indicated at 150. in Figure 2. Attached. flanges 20d abut, when. member 20 is so positioned, against a portion l'lb ofthe carriage so that this member is eifectivelylocked against longitudinal It is clear that, after assembly of member 20 with a supporting tine in the manner I movement;

just described, this'member cannot move unless by reversing the process of assembly, i. e. tilting it to the position shown in Figure 9 and sliding; it outwardly along thetine and really is an inte gral part of the tinefor all purposes.

I Two such members 20 are preferably provided, 1

20c, which edges are in alignment when the two members are fully positioned as shown in Figure 1. These two edges or shoulders 20e together.

comprise one portion of the separable connection between pallet S and the truck, the other portion being the hook l8.

-When the forks l5 and added members 20 are inserted beneath a loaded pallet S, and the pallet is'lifted, thehook member [8 will not be caused, by such simple lifting movement, to actually engage the edges Zoe. However, should there be any forward movement of the pallet upon the tines I5 as the truck is'manipulated, the hook member will, aftera short forward travel of'the pallet,

engage the edges 20c as seen in Fig. 7, thus preventing further travel of the pallet and its load off the fork lift. When a load is to be discharged and the pusher P is actuated while the truck is retracted the pallet S, if its hook I8 is still spaced from edges 206, will of course slideforwardly with the moving load until'the hook 18 engages edges 211e, further movement of the pallet upon its support being then prevented so that the palletv may be withdrawn with the forks from beneaththe load which it ha'sbeen supporting. Because of the fact thatthe hook l8; engages the undersides as well as the'edges of members 20 the ML let is prevented also from tilting as the load passes over its forward edge, '1. e. the edge thereof remote from the hook.

Disengagement of the pallet may be readily ef-' fected either by loweringthe pallet to the ground and then slightly advancing the forks, further lowering and then retracting the fork lift, or by rearwardly tilting the mast and thus causing the pallet to slide toward the truck body. .This last ment members may be employed, if desired. In

any event the means for detachably securing the pallet to the truck must be so formed that the pallet will not only be restrained from sliding too far forwardly during an unloading operation but will also effectively prevent tilting of-the .pal-

..-lettabout"the; ends: of. the tines l operation.

Thenovel.mechanismso far described may be. utilized whether: or..not. the. truck is equipped with a;.pushing element such as: illustrated in For the purpose of. mostv conveniently unloading such'a cargo from a boxcanandstoringit 1113a, warehouse a truck and three pallets can be: used: with great economyas compared with unloading methods now commonly practiced;

Incarrying -out such unloading operation-one of the -load supporting pallets would be placed adjacent the, door of the car to be unloaded, the two legs of this pallet resting directly upon the; car bottom and the opposite end being supported upon blocks, for instance wooden blocks one of which is indicated at B in Figure 11', so that the pallet floor will be disposed horizontally; Actually, the pallet S could be merely a plate equipped with a'hook l8 and supported entirely 'by' blocks. The supports or legs are really important however to allow the .-forks to be disengagedcfromv the hook 18 by the mere manipulation of the forks. Four men will then pile a predetermined number. of sacks upon the pallet, such a pile of sacks being illustratedin'Figure 11. This can be readily accomplished. The lift truck would then ad- Vance; the fork lift platform F inserted under the pallet, as illustrated inFigurell, and thecarriage C elevated so that the fork lift with its superposed load will be lifted. The truck will then be operated to transport the load to the storage area. At the point of load discharge: the. operator will cause the mast of the truck to tilt forwardly to a position such as that in which it is illustrated in Figure '12, thecarriage and fork lift platform likewise being tilted. forward as shown. If the load is to be deposited directly upon the r'loor-the tilting operation will bring the forward edge of the'pallet S into contact with the floor, thecarriageC occupying such position that tilting to an angle of 2 or 3 or thereabouts will'have this result. The operator would then cause the carriage C 'to move upwardly for the fraction of an inch, for instance about a quarter of an inch, thus causing the forward edge of the palletto be elevated above the fioor-that-amount.

The hydraulic mechanism H is-then energized tocause the pusher frame P to move forwardly and, simultaneously, the truck is. backedaway. The pallet. S is thus withdrawn from beneaththe pile of sacks which'a're' held'agains't lateral movement b'y'the pusher element P. As the'pall'et S is withdrawn from beneath the sacks comprising the pile, these sacks pass over the forward'bew el'ed edge of-the pallet and drop-to the floor. The drop-is so slight, however, that there is no break-- age of any'sackas it passesover theedge of the pallet and'there'is, furthermore,-no such relative movement between the sacks as to causethe pile to lose formation. The entire'pile will be delivered intact "and intight pile formationupon the. selected space, without possibility ofbreakage or disruption of any sack.

Should one load already have been deposited on this selected storage area as'in-Fig. 12, and itbedesired to deposit. a second load on topof 'known methods.

therflrst, the procedure will be the same.

in that; the pallet-S and theload carried thereby wi1l;beelevatedby'moving the supporting; carriage C upwardly,- forinstance to the position shown. in Figures. 12 andlS. The unloading op erationswill take. place, however, just as before... thetruck being backed away whilethe pusher perating mechanism is actuated in such manner as to'hold the load stationary. If desired a third load. may be deposited in this manner upon the,

top of. the second and the resulting pile will be stable, the individualzincrements depositedhaving been. maintained in tight pile formation be-- cause' each.was.made.to drop an extremely'in.

consequential distances After. each: load .is deposited the .lift truck will return :to' the; box car, the pallet being preferably released while the. truck is on thisreturn movement, the operator: tilting the mast. backwardly so: that; .the. pallet; slides toward the truck .until thehook l8 disengages' the catch members 208..

When the truck' arrives at the loading stationtherefore, the 'pallet may be readily deposited upon thefloor by simply lowering the carriage C until the. palletmakes, contact with thefloor, the

fork lift being. then retracted as legs or supports Also; where other engaging means are used, it

may be desired to. remove-the pallet manually and legsmaybe dispensed with, .the pallet being entirely supported byblocks to allow the forksto enter: thereunder. The truck will then 'be moved to pickup a pallet which has previously been loaded and will carry this loaded pallet to the.

ischarge area and eifect the discharge of the sacks. .therefromdn the manner previously de scribed; The sacks are'piled one upon another and the use of conventional pallets is wholly avoided. Not only is there a substantial saving realized by reason of the fact that the use of conventional pallets is avoided but there is also realized-a substantial saving in labor even though as many men are required in an'unloading operation effected by-means of a truck equipped with the novel mechanism described-as are customarily used when the unloading operation is effected 'bymeans I of the conventional pallet. It isactually found that the labor costs may be reduced by about 15%, in .the unloading of'a car containinga-specified number of sacks, this sav-- stead of a large number of pallets, say- 40 pallets in the caseof a car of normal capacity.

When flour in sacks is to be loaded into abox car, instead of being removed therefrom, much greater economies are realized as compared with Thus, in such a reloadingoperation effected with the aid of the improved mechanism'described, only two men will be required as the lifttruck .can place the palletwhere itis-wanted without handling. The pallets are 'loadedwithin the warehouse ormill and the lift truck transports a load to the carand deposits it in the car, successive loads being placed one upon the other by the. truck. to the limit permitted by the height of the roof, without, as previously explained, any handling. Indetermining thenumber. of bags to-be incorporated into each successive load. consideration must be given to the. distancethe machine .travels from the point ofv loading of the pallettothepoint of. discharge of the load in the box car, the loads being preferably so made up that the men loading the pallets can always be ahead of the truck. This permits the truck to travel continuously at its maximum speed so that the most economical results are, in this respect, realized. Two men can, without undue exertion, load pallets slightly faster than the truck can remove them, the operation being so planned and, toward the end of the loading may have loaded several skids or platforms in excess of the number withdrawn by the truck. The men who have thus been actually loading the pallets within the warehouse may then move to the car and assist in the manual storage within the car of that portion of its loading which must be stacked by hand, i. e. the area adjacent the door of the car. When three men are thus used to load a car the saving of labor, ascompared with the situation in which conventional pallets are used and involving the employment of five men, is approximately 40% and, in addition, there are no empty pallets to handle so that the saving can and frequently does amount to 50% over present methods employing conventional pallets. On the complete operation of unloading, storing and reloading a box car there may thus be an overall labor saving over present methods, of 25% to 30% of the total actual labor costs and this is in addition to the additional saving realized by dispensing with the use of a large number of pallets.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A load carrying pallet for a fork lift truck, adapted to be loaded, picked up and transported, said pallet comprising a rigid plate having means aiiixed thereto for supporting one edge only so that the pallet, when placed upon a horizontal support, will be inclined, and a hook attached to the underside of the pallet adjacent the edge so elevated and extending downwardly and inwardly, for the purpose set forth.

2. A load carrying pallet for a fork lift truck, adapted to be loaded, picked up and transported, said pallet comprising a rigid plate, and a hook attached to the underside of the plate extending downwardly and inwardly, for the purpose set forth.

3. In a combination of the class described, a lift truck having a lifting platform with a detentengaging surface, said platform being adapted to 10 a carry a load by application under the load, a thin sheet-like pallet adapted to be lifted by said lifting platform, locking means extending downwardly from said pallet and coacting with said detent-engaging surface for locking said pallet against substantial sliding relatively to said lift-1 ing platform when resting in a predetermined position on said platform, said locking means including a portion for locking said pallet against tilting upwardly off said lifting platform as when said pallet extends unsupported forwardly beyond said lifting platform and a load is applied to said forwardly extending portion.

4. In a combination of the class described, a lift truck having a lifting platform adapted to carry a load by application under the load'and having a detent-engaging surface, a thin sheetlike pallet adapted to be lifted by said lifting platform, means extending downwardly from said pallet and coacting with said detent-engaging surface for locking said pallet against substantial sliding relatively to said lifting platform when resting in a predetermined position on said platform, said means including a portion for locking said pallet against tilting upwardly off said lifting platform as when said pallet extends unsupported forwardly beyond said lifting platform and a load is applied to said forwardly extending portion, andsaid means being so positioned relatively to said pallet as to maintain said pallet with one edge against the ground and the floor of the pallet angular to the ground when the pallet rests on a flat piece of ground.

GEORGE BEVAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,524,473 Brinton Jan. 27, 1925 1,896,543 Gfrorer Feb. 7, 1933 1,934,289 White Nov. 7, 1933 2,256,454 Bomar Sept. 16, 1941 2,302,137 Neuman Nov. 17, 1942 2,412,155 Jessen Q. Dec. 3, 1946 2,421,128 Pride May 27, 1947 2,441,750 Britton May 18, 1948 2,452,356 Goit, Jr Oct. 26, 1943 2,468,055 Gibler Apr. 26, 1949

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