US2726000A - Crate handler for lift trucks - Google Patents

Description

Dec. 6, 1955 Filed July 13, 1953 G- F. QUAYLE CRATE HANDLER FOR LIFT TRUCKS 3 Sheets-Sheet l INVENTOR G F Quay/ 2;

ATTO R N EY Dec. 6, 1955 G. F. QUAYLE CRATE HANDLER FOR LIFT TRUCKS 3 Sheets-Sheet 2 Filed July 13, 1953 :ll'll. 11-1:- HHUULILILILILYIULIUUU i m llmlnlmll ll INVENTOR 4 BYfl It--- a w/vx ATTORNEY Dec. 6, 1955 G. F. QUAYLE 2,726,000

CRATE HANDLER FOR LIFT TRUCKS Filed July 13, 1953 5 Sheets-Sheet 3 I I \\\\\\\\\\\v////////I///4 INVENTOR 5Y6: F WMM ATTORN EY United States Patent CRATE HANDLER FOR LIFT TRUCKS George F. Quayle, Philadelphia, Pa., assignor to The Yale & Towne Manufacturing Company, Stamford, Conn., a corporation of Connecticut Application July 13, 1953, Serial No. 367,505

8 Claims. (Cl. 214-653) This invention relates to industrial lift trucks, and more particularly to means through which the lifting carriage of a truck of this class is adapted to engage a transverse rail of a crate for lifting the crate.

The prior art utilizes for this purpose arms or grabs that extend forwardly from an upper portion of the lifting carriage. Through forward movement of the truck, these arms are brought into position under the rail of a crate. The carriage can then lift the crate by its rail, with the crate swinging on its rail until a lower portion of the crate rests against a part of the carriage. This arrangement is of considerable value because it enables the truck to handle crates without pallets.

The lifting arms or grabs that are utilized in the prior art can subject the crate to twisting or racking forces tending to loosen parts of the crate, thereby damaging the crate. This is because the arms or grabs engage the transverse rail of the crate at an angle to the lifting carriage if, as is very often the case, the truck has not approached the crate squarely. Then, as the crate swings on its rail toward the carriage as it is being lifted by the arms, the weight of the crate acts to square the lower portion of the crate relatively to the carriage. Since the rail cannot also be squared relatively to the carriage because of its contact with the arms, a twisting action results between the lower part of the crate and the rail that damages the crate and tends to disengage the crate rail from the lifting arms or grabs.

I have conceived an extremely novel lifting means of this class in which the arms or grabs yield to prevent a twisting of the crate. Thus, the arms or grabs allow the rail to move into the same square relation to the lifting carriage that is occupied by the lower portion of the crate. Specifically, because the rail is allowed to move against the lifting carriage as the lower portion of the crate swings against the carriage in square relation thereto during the lifting operation, the lifting arms or grabs do not subject the crate to twisting or racking forces.

More particularly, each grab normally extends from the lifting carriage a sufiicient distance to enter into lifting position under the transverse rail of the crate when this rail is spaced from the carriage. Upon lifting movement of the carriage, the weight of the crate causes the grabs to move toward the carriage. If the crate rail is positioned initially at an angle to the liftingcarriage, the grabs will allow the upper part of the crate to move into square relation to the carriage, as the lower part swings on the rail against the carriage. As a part of this feature of my invention, I preferto mount each grab for movement to a completely retracted position relatively to the other grabs. Through this arrangement, a grab that can not move into position under the transverse rail will move 'rearwardly as the other grabs move the crate toward the carriage, and therefore will not interfere with movement of the crate into a square position relatively to the carriage.

. As a more detailed feature of my invention, I utilize pivotmeans for mounting the .grabs on the lifting carriage.

lc l atented Dec. 6, 1955 The pivot axis is so arranged relatively to each grab that the weight of the load effects rearward movement of the grab, with the crate moving against a part of the carriage.

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 a side view showing my novel crate lifting means mounted on a lift truck, in position preparatory to lifting a crate. V

Fig. 2 is similar to Fig. l, but showing the crate lifted and drawn toward the lifting carriage on the grabs.

Fig. 3 is a plan view illustrating an angular approach of the lifting means relatively to the crate.

Fig. 4 shows the position of the parts when the crate is lifted following the angular approach shown in Fig. 3.

Fig. 5 is a partial front view illustrating my novel lifting means.

Fig. 6 is a sectional detail view on the line 6--6 of Fig. 5.

Fig. 7 is a sectional view on the line 77 of Fig. 6.

For the purpose of describing my invention, I show in Figs. 1 and 2 of the drawings a lifting carriage 10 that moves vertically on uprights 11 of an industrial truck. I show my novel crate lifting means, indicated generally by the numeral 12, as an attachment mounted upon the carriage 10 through lugs 13, 14. The particular mounting of the crate lifting means 12 is not important to an understanding of my invention, however, and it is necessary to know merely that the lifting means 12 is functionally an integral part of the carriage 10 and moves vertically with the carriage.

The crate lifting means 12 comprises essentially a series of novel grabs 15 mounted on a transverse shaft 16 that extends across an upper portion of the lifting means, as will be seen by reference to Figs. 1, 3, and 5. The shaft 16 is mounted in turn on downwardly extending end portions 17 of an upper cross member 18, these end portions 17 being attached integrally to vertical members 19 of the lifting means 12. A lower cross member 20 extends between the end portions 17 at the upper ends of the vertical members 19, and I mount vertical struts 21 between the upper and lower cross members 18, 20 to provide further support for the shaft 16. For reasons that will appear, I prefer to utilize for the lower cross member 20 an angle member having an upwardly extending flange 22. It is important to understand that the front edge of vertical members 21, together with other surfaces of lifting means 12 form a vertical support surface against which the crate is squared as hereinabove set forth.

It is extremely important to observe that each grab15 is formed to extend downwardly from the transverse shaft 16, with a toothed lifting surface 23 on the grab positioned below the shaft 16 and normally extending in a forward direction relatively to the shaft. I have shown the toothed lifting surfaces 23 formed on plates 29 that are attached to the grabs 15 by rivets, but it will be understood that these surfaces may be integrally formed on the grabs if so desired. a 1 a j a In more detail, as best seen in Figs. 6 and -7, each grab 15 has at its upper end a cylindrical bearing 24 whereby the grab pivots on the shaft '16. Around the bearing 24 is a coil spring 25 having an arm 26 engaging the rear edge of the cross member 18, and an arm 27 positioned in an opening in the grab 15. The spring 25 presses the grab -15 in a counter-clockwise direction on the shaft 16, as viewed -in Fig. 6, with an end part '28 on the 'grab 15 engaging the flange 22 on the cross member 20 to define a normal forward position of the grab 15. In this normal. position of the grab, the toothed lifting surface 23 is positioned forwardly relatively to the shaft 16, and also extends forwardly a considerable distance relatively to the front of the lifting means 12. The spring 25 nevertheles can yield to allow the grab 15 *to move rearwardly, and does in fact permit the-grab to move to a fully retracted position.

To clarify the operation of my novel crate lifting means, Ihave shown it in Figs. 1, 2, 3, and 4 in various positions relatively to aerate C. Referring first to Fig. l, the lifting carriage is in a lowered position on the truck uprights '11, and the truck has approached the crate C. In the particular example, the truck in stopping has left a space between the front of the lifting means 12 and the crate C, but the lifting surfaces 23 of the grabs 15 do extend under an upper transverse rail 'R of the crate C.

I show in Fig. 2 the position of the parts when the carriage 10 has moved upwardly from the position of Fig. 1. The lifting surfaces 23 have now engaged the crate rail Rand have lifted the crate. The weight of the crate C on the lifting surfaces 23, because of the position of these surfaces relatively to the pivot axis of each of the grabs 15, has swung the grabs rearwardly. Thereby thelifting surfaces -23 of the grabs have allowed the crate rail R to move against the front vertical support surface of the lifting means. Simultaneously, the lower part of the crate has swung also against the vertical support surface.

Let us assume now that the truck approaches the crate C at an angle, this condition being illustrated in Fig. 3. The lifting means 12 can not new approach the crate C as closely at one side as at the other side. Therefore, the lifting surfaces 23 of the grabs 15 extend different distances under the crate rail R, as is clearly shown in Fig. 3.

If the crate is now lifted by the upward movement of the grabs, the weight applied to the individual grabs 15 causes these grabs topivot rearwardly, as from the position of Fig. 1 to the position of Fig. 2, thereby allowing the rail R to move into square relation to the vertical support surface of lifting means 12, as illustrated in Fig. 4. The lower portion of the crate swings on rail R into a square position against the vertical support surface. Therefore, while the grabs 15 have lifted the crate C from an angular position relatively to the truck and its lifting means, it will be seen that the truck supports the crate in a square position and does not subject the crate to twisting or racking forces.

Those skilled in the art will readily appreciate the considerable value -of my invention to the industry, made possible by a novel concept involving but slight changes in present structures.

I new claim:

1. In a truck of the class described, a-lifting member, a series of crate lifting grabs having surfaces adapted to be applied to the underside of the rail of'a crate, each of said grab surfaces entering into a different lifting engagement with the rail when positioned to extend different distances under the rail as when the crate is angular to the lifting member, andmeans mounting each of said grabs on said lifting member formovement inwardly of said lifting member integrally with said rail of thecrate when saidcrate swings-on'said' grabs toward the lifting member.

2. In a truck of the class described, a lifting member,

a series of crate lifting grabs having surfaces adapted "to 'be applied as meuaaersia'e of the rail of 'a crate, each of said grab surfaces entering into a different lifting engagement with the rail when positioned to extend different distances under the rail as when the crate is angular to the lifting member, and means pivotally mounting each of said grabs -on said lifting member for movement-inwardly of said lifting member integrally with said rail of the crate when said 'crate swings on said grabs toward said lifting member.

3. In a truck of the class described, a lifting member, a series of crate lifting'grab's/each grab having a lifting surface normally positioned forwardly from said lifting member and adapted to be applied to the underside of the rail of a crate, and means-pivoting each grab relatively to said lifting member on an axis above the lifting surface of the grab whereby the rail of the crate when lifted on the lifting surfaces swings the grabs inwardly of t-he'lifting' member.

4. In a truck of the class described, a lifting member, a series of cr'ate lifting grabs, each grab having a lifting surface normally extending forwardly from said lifting member, said grab surfaces entering into different lifting engagement with the underside of a rail of a crate when positioned to extend different distances under the rail aswhen the crate is angular to the lifting member, and means pivoting each grab relatively to said lifting member on an axis above the lifting surface of the grab whereby the grab when lifting the rail of the crate on its lifting surface moves inwardly on its pivot as the rail moves into a position squared with said lifting member.

'5. In a truck of the class described, a lifting member, a series of cr a'te lifting gra'bs, means mounting each .grab on said liftingmember for movement relatively to said member, -a' lifting surface on each grab below its mountingmeans adapted to be applied to the underside of the upper rail of aerate, yielding means pressing each grab forwardly on its mounting means with the lifting surface of each grab in position to enter into lifting engagement with the-crate rail, the lifting surfaces of said grabs adapted to extend different distances under the rail when the crate is angular to the lifting member, stop means on the lifting member against which a'lower portion of the crate swings when the grabs lift the crate through its upper rail, and said grabs when lifting the rail of the crate moving with said rail against the pressure of said yielding means to align the crate rail with the stop means on said lifting member whereby not to twist said crate.

6. In a truck of the class described, a lifting member, a series of crate lifting grabs, apivot mounting each-grab on said lifting member for movement relatively to said member, a lifting surface on each grab below the pivot axis adapted to be applied to the underside of the upper rail of a crate, yielding means pressing each grab forwardly on-its pivot with the lifting surface of each grab in'position to-enter into lifting engagement with the crate rail, the lifting surfaces of said grabs adapted to extend different distances under the rail when the crate is angular to the lifting member, stop means on the lifting member against which a lower .portion of the crate swings when the grabs lift the crate through its upper rail, and said grabs when lifting-the-rail ofthe crate moving with said rail against thepressure of said yielding means to align the crate rail with the stop means onsaid lifting member whereby-not to twist said crate.

7. -In a truck of the class described, a lifting member, a'series of crate lifting grabs, means mounting each grab independently on said lifting memberfor movement relativelyto saidmember, a lifting surfaceon each grab below its mountingmeans adapted to be applied to the underside ofthe upperrail of aerate, upper stop means for the crate rail on said :lifting member yielding means pressing each grab on its mounting means to hold the lifting surface of each grabnormally imposition toenter into lifting engagement with the crate rail-forwardly of said upper stop means, the lifting surfaces of said grabs adapted to extend difierent distances under the rail when the crate is angular to the lifting member, said grabs when lifting the rail of the crate moving against the pressure of said yielding means whereby to move said rail into position with its edge against said upper stop means, lower stop means on the lifting member against which a lower side portion of the crate swings when the grabs lift the crate through its upper rail, and the edge of said upper crate rail when against the upper stop means positioned parallel to the side portion of the crate that is against said lower stop means whereby not to twist the crate.

8. In a truck of the class described, a lifting member, a series of crate lifting grabs, a pivot mounting each grab on said lifting member for movement relatively to said member, a lifting surface on each grab below the pivot axis adapted to be applied to the underside of the upper rail of a crate, means holding each grab normally with its lifting surface forwardly of its pivot in position to enter into lifting engagement with the crate rail, the lifting surfaces of said grabs adapted to extend different distances under the rail when the crate is angular to the lifting member, stop means on the lifting member against which a lower portion of the crate swings when the grabs lift the crate through its upper rail, and said grabs moving rearwardly in response to the weight of the crate to place said rail in aligned relation to the crate portion that is against said stop means whereby not to twist the crate.

References Cited in the file of this patent UNITED STATES PATENTS Ulinski Apr. 27, 1954

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