US2667283A

US2667283A - Lift truck

Info

Publication number: US2667283A
Application number: US6952A
Authority: US
Inventors: William W Macdonald; John R Pomfret
Original assignee: PETERBILT MOTORS Co
Current assignee: PETERBILT MOTORS Co
Priority date: 1948-02-07
Filing date: 1948-02-07
Publication date: 1954-01-26
Anticipated expiration: 1971-01-26

Description

Jan 26 1954 w. w. MacDoNALD x-:TAL 2,667,283

LIFT TRUCK Filed Feb. 7, 1948 3 Sheets-Sheet l Wwf ATTORNEY.

Jan. 26, 1954 w. w. MacDoNALD Erm.

LIFT TRUCK Filed Feb. 7, 1948 5 Sheets-Sheet 2 RT H mw. M 0 wm. n ,mn A Il Lil WO M\/- llllun 2H?, i /w L MM mlmh. WJ @wlw m Y f mim .lil B u ..2\M\ .,M a A 2 .,Aimnu., u

Patented Jan. 26, 1954 LIFT TRUCK William W.'MacDonald and John R. Pomfret,

San Francisco, Calif., assignors, by mesne assignments, to Peterbilt Motors Company, a corporation Application February 7, 1948, Serial No. 6,952

1 Claim.

vary in the diameter of `the rolls very consider-` ably and are difficult to manage, inasmuch as there .are no handhelds or other means whereby a good purchase could be obtained in order to lift, transport or position the said rolls.

It is common practice, in warehouses and terminals or similar places of material-handling, to utilize lift trucks in order to move the bulky merchandise from place to place at a rapid tempo. However, most lift trucks and clamping mechanisms, in present use, are not suitable to handle rolls of paper. The principal difficulty in handling rolls of paper, by means of heretofore known lift trucks and lifting mechanisms, lies in the fact that the rolls are of great weight, vary in d1- ameter and present a smooth, round surface which does not offer a suitable surface with which to grip the roll. It is possible, of course, to handle rolls of paper by placing the said rolls in a horizontal position and handling them from thathpo.- sition, but to lift a roll and move it when it is upright is a very diicult if not impossible procedure with heretofore known lift trucks.

It is the principal object of the present invention to provide a lift truck with means whereby rolls of paper, or similar objects of great Weight, may be lifted, when in upright position, and moved from place to place.

It is a further object of the present invention to provide a lift mechanism, for use on lift trucks, with self-adjustable` clamping means whereby rolls of paper of varying diameters may be gripped firmly and securely without manual adgustment of the clamping mechanism.

It is a further object of the present invention to provide a self-adjustable clamp for lift mechanisms for use on lift trucks, or the like, which is entirely safe in operation and which securely holds a roll of paper, or the like, when said roll is in upright position. y

It is a further object of the present invention to provide a lift mechanism adaptedhto grip securely a roll of paper, or the like, while said roll is in an upright position and then, subsequently,

rotate the roll through a 90 arc to place the said roll in a horizontal position.

A further object of the present invention is to provide a clamping mechanism for lift trucks, or the like, wherein the clamping plates are adapted to adjust themselves automatically to dierent radii of Work being handled, as, for example, rolls of paper of different sizes and types.

A further object of the present invention is to provide a mechanism of the character mentioned, which is rugged in construction, relatively simple to manufacture, assemble and operate and which is comparatively inexpensive.

Further objects and advantages will become apparent upon referring to the specification and accompanying drawings in which similar characters of reference represent corresponding parts in the several views.

Referring to the drawings:

Fig. 1 is a side elevational View of a lift truck having a novel work-clamping mechanism carried thereby.

Fig. 2 is a top plan View of the lift mechanism and clamping mechanism.

Fig. 3 is a side elevational View of a fragmentary part of a lift truck and clamping mechanism taken from a side opposite from that indicated in Fig. 1.

Fig. 4 is a top plan View of a modification of the invention.

Fig. 5 is a side elevational view of the modification illustrated in Fig. 4.

Fig. 6 is a front elevational view of the modification of the clamping mechanism illustrated in Figs. 4 and 5.

As illustrated herein, the novel clamping mechanism is carried by a lift truck, indicated generally at 2, which may be of conventional design and carries at the front end thereof a vertical lift hoist, indicated generally at 3-. Carried by the lifting mechanism is a clamping mechanism, indicated generally at 4, which said clamping mechanism is adapted to grip an article to be transported, such as a roll of paper, illustrated generally at A. The lifting mechanism 3 comprises a vertical mast or hoist guide frame 5, which said frame comprises frame plates 6 and 'l which are adapted to4 be elevated and lowered in unison in the frame at the will of the operator of the truck through a suitable conventional lifting power mechanism and control therefor (not shown).

The clamping mechanism, indicated generally at 4, comprises a vertical plate 8 which carries a shoe 9, which said shoe 9 is adapted to engage the lifting plate 6 so that the clamping mechanism is elevated or lowered in accordance and in unison with the lifting plates 6 and 11.

' The clamping mechanism frame, to which the plate 8 is rigidly aiixed, comprises two vertically spaced, horizontally disposed frame plates II and I2, having a frame spacer member I3 disposed vertically therebetween and adjacent to one side.1thereofandfwhich saidspacer member is rigidly afxedto each of said-plates II and I2.

The fore endV plates II and I2 are formed ar.-

Dpposite from.;plate I1 there -.is-,disposed aY verticalzpivotqpin 2|, journaledingplates II .and

y I2,;.adjacent .to-the forward, end .thereofand `disposed therebetween. ,Rotatablymdunted on pt disposed horizontally .betweenplates IIl and.l2.

V`Between the zplates 22 :and ,-23 and -rigidlysecured -thertois a .channel-shaped :arm .24%, which rsaid arm fextends, forwardly-.beyond plates II and A invention disclosed in Fiss. l, .2 and B, and.

-2I are plates 422r and, which said platesra-re 25,

I2 and plates ,'22 and,2;3 to a position substarb tially diametrically .opposed to the forward end .zofclamping armor'plate I1. The arm 213 ,mounts a Vverticallydisposed v*pivot pin 25, to Vwhich 4is pivotally .attached an arcuate clamping plate lil.

The clamping -plategor arm I1 and clamping plate y I8 are provided with load-engaging surfaces having substantially thesame .degree .of curvature as each other and the platev I. The clamping plate I8, hereinafter sometimes referred toas a floating plate, is hingedly mounted on theforward Y .end-ofzarmZ `and lmay pivot freely with respect thereto for self adjustment to the :curvature of thegloadY being handled bythe lifting apparatus. The:movement of the vfloating plate I8 vis -indivvcated in dotted lines in Fig. 2, showingv thesame as applied to the load B of lesser diameter than that lindicated by the reference indicia A. Thus the oating plate insures a tight gripping of'work being handled` `by the device. Y

It is further noted that the leading edge-of vthe rigid clamp plate I1 extends in a-forward V.(,lirection and .is .adapted to extend between rolls of paper, or the like, positioned yin yclose progrimity to one another, thus serving as an entering wedge to guideor positionthe rollrelativeto the clampingplates I1 and I8. The rotatable-arm 2t is actuated from releasing toggripping position, and viceversa, .by-a :hy-

Adraulic ram mechanism, generally, `indicated. at .26. The ram mechanism .".i comprisesa cylinder y21,- which is ,pivotally connected, as at .28, to frame spacer'member vlil-tor' movement ,in-a Vplane parallel .tohorizontal pla-tes l I and I2. .Disposed wi'thin cylinder 21 .is .a piston. 2S, .to which is rigidly-afXed-a piston irod 3|,.which, in turn,.

jpivotally connected to a -pivotpin 32 ,mounted `on plates 22A andl 23 .at-the rearwardend` thereof. :The ram mechanism lis of the doubleacting type 1`havinga fluid connection, as atSS, at .oneend thereof and, as at 3s, at the other end thereof. vThe fluid source and valvemechanism to .control entry and `discharge of ,hydraulic fluid .into and from cylindei` 21 are not shown and may A.be ,of the conventional type well .known inthe art. Arm '21%, with attached noating :plate 1.8, may .be

moved arcuately to and from the .work handled 4 by operation of the ram mechanism 26 through suitable control mechanism conveniently available to the driver of the lift truck.

A modification of the present invention, as

rshown in Figs. 4, 5 and 6, embodies the features voff-the inventionghereinabove mentioned with respect to--the floating plate,-rigidplate Yand movable arm, to which the floating plate is attached.

*In addition to these features, the modification ^`Tshows a means whereby the work may be rotated through an arc of 90 after the work has :been .clamped.rsecurely in position and elevated. "Thaabilityto rotate work being handled through `'an Iarc Aof 90" ,after elevation thereof, is particularly useful certain material handling operations, .such as loading rolls of paper, or the like,

on truck beds, or the like.

Thelmodincation of the invention illustrated in Figs. 4, If5 and 6 utilizes the same construction generally as thatdescribed with reference'to the therefore, referencey numerals referring .to commonparts will be used. -The vrnodilcation com- ;.prisesfa .rigid vertical plate 5I whichcarries shoes-52 adapted to ,coast Withthe plate 6in :thesamemanner describedwith reference to Figa i, 2 .and 3. r,Aiiixed rigidly-to the plate .5I

thereto. `The .hublt extendsforwardly ,betweenv the .plates il .and 11,2 O f the clamping mechanism, generally indicated at, .andwhichhas 'heretofore been fully described. Rigidly positioned `between the plates I I .and I2 and securedthereto Vlis atransverse plate' 58,' to which is rigidly mounted the` flange '151. vThus rotation of axle 56, with respect to hub 54, will cause `rotation of the entire clamping mechanisml.

The` mechanism for causing Arota-tien -of the clamping mechanism about the horizontal axis ofthe hub 5e, which is indicated generally atei] inFigsgB ando, willr now be described. Attached .tothe upper'front portion ofV ythe elevating device, .as indicated atfiiI, and 'which said device travels in nnisonwith the lifting plates 6 in the hoistv mast,.'is a forwardly #projecting pin^2,.to which is pivotally mounted, as at 633, a hydraulic cylinder lill. The cylinder' 534 contains a: piston head, to which'is attached rigidly `a piston rod 65, Which,'in turn, is pivotallly connected to a ,pin 67,-Whch said pin is rigidly secu-red 4-to the `,bottom ofuplate l IA adjacent 'to onev side thereoi near 'the rear. 'The actuating mechanism 6I! comprises the cylinder 64 of the ydoulzlle-acting type, having a point -of entry, -as lat'-'ll and 12,

`mecl'ianisrn may be, of suitable conventional type well known Yin thegart. Thus, upon-actuation of tlfie piston B5, the clam-ping mechanism fmayfbe rotated about the 'axis' of -axle 56,as illustrated in dotted lines in Fig. 6.

'In operation, the clamping mechanism iszpositioned about theloadtobehandled-and the floating, plate It adjusts itself l,au-tomatically to -the degree of'curvature of'thesaidload. The

`operator of the' ;lifting device' then actuates-:the ram .assemblyZ Yin order tomove thearm 214 toa clamping position relative to the -workland rigid arm l1. The clamp mechanism is then elevated in the usual fashion through the hoisting mechanism 3. After the load has been elevated, the operator of the lift truck may then actuate the ram mechanism 60, through suitable conventional control means (not shown) in order to rotate the clamping mechanism about the axis of rotation of axle 55 in order to position the load in a horizontal position, asA indicated in dotted lines in Fig. 6. The operator may, of course, reverse the movement of the piston 65 and piston rod 66 in order to return the load being handled to a vertical or upright position, thence lower the same by means of the lifting mechanism, and then release the load by return operation of piston 29 and rod 3 l One of the main advantages of the present invention is the ability of the device to position a roll of paper, or the like, with respect to the clamping plates. Thus, if rolls of paper, or like material, are stacked side by side in close proximity to each other, the rigid clamp or guide plate I1 serves as an entering wedge between adjacent rolls of paper, or the like, in order to pry them apart and position the article to be lifted relative to the clamping mechanism. Further, assuming that the rolls of paper to be transported are in horizontal position, the modied form of the present invention may be rotated to position the leading edge of the rigid plate parallel to the lower surface of the roll and may then be wedged beneath the roll to serve as a scoop in order to position the said rollrelative to the clamping mechanism. Then the arm 24 may be actuated to clamp the ioating plate i8 against the upper surface of the roll in order to grip the same securely. Thereafter the roll may be elevated by the lifting mechanism and, once elevated, may be transported in horizontal position, or the clamping mechanism may be rotated to position the roll in upright or vertical position.

The floating plate i8 is very important in order to grip securely the load being transported. Particularly advantageous is the function of the floatingplate in use with rolls of paper of varying diameter and wherein the sides of the rolls vary from one another in degree of curvature. The floating plate adjusts itself to the particular curvature of the surface to be gripped without need of manual adjustment thereof and enables an effective clamping pressure to be exerted against the roll of paper, or thelike, to insure a positive grip. For example, to lift glossy or smooth-finish paper rolls, a positive grip is essential in order to insure safe and economic requirement of a positive gripping position of l clamping members relative to load even when handling rolls of different diameters.

The invention has been described in specic detail with respect to assembly and construction by way of example and illustration for purposes of clarity of description and understanding, but it is understood that various changes, alterations and modifications in structure and assembly may be practiced within the spirit of the invention and scope of the appended claim.

We claim:

In a lift truck having a hoisting mechanism, the combination of a rigid frame, a connection to connect said frame to said hoisting mechanism comprising a rotatable element, a rigid arm having an arcuate load engaging surface connected rigidly to said frame, a movable arm connected pivotally to said frame and spaced from said rigid arm, a clamp plate having an arcuate load engaging surface mounted pivotally on said movable arm, an arcuate load support connected rigidly to said frame and disposed between said rigid arm and said plate, means connected to said frame to move said movable arm and plate toward and away from said rigid arm, and means connected to said frame to rotate said frame and attached arms about the axis of rotation of said rotatable element, said last named means comprising a cylinder secured pivotally to said lift truck, and a piston having a piston rod reciprocal in said cylinder, said piston rod connected pivotally to said frame. l

WILLIAM W. MACDONALD. JOHN R. POMFRET.

References Cited in the le of this patent UNITED STATES PATENTS Adde June 20, 1950