US1528749A - Lifting truck - Google Patents

Description

, Filed June 15, 1921 2 Sheets-Sheet 1 i Inxfeni 12 E 1' 5 A 1/! V M W1, W

March 10, 1925. 1,528,749

- A. M. BARRETT LIF'I'ING TRUCK Filed June 13, 1921 2 Sheets-Sheet 2 "LII Patented Mar. 10, 1925. I

UNITED STATES ARTHUR M. BARRETT, OF WINNETKA, ILLINOIS.

LIFTING TRUCK.

Application filed June 13, 1921.

To all whom it may concern:

Be it known that I, ARTHUR M. BARRETT, a citizen of the United States, and a resident of VVinnetka, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Lifting Trucks, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to trucks of the type known as lifting trucks, which comprise a low lying main frame mounted on wheels and supporting a rising and falling lifting frame which, when in its lowered position, is adapted to be backed under a platform the deck of which is slightly higher than the lifting frame of the truck when the latter is in its normal or lowered position. By then raising the lifting frame the platform with its load is lifted from the floor and may be transported on the truck to some other point to be there deposited by the lowering of the lifting frame. My present invention has for its object to provide certain improvements in trucks of this description bv which the truck is better adapted for effective use in raising either heavy or light loads in that provision is made for obtaining greater lifting power where heavy loads are to be lifted, whereas where the load is light and less power is required the load may be lifted more quickly. To this end my invention generically considered consists in providing means for varying the leverage through which the lifting power is transmitted to the lifting frame. As further improvements my invention also contemplates the inclusion of such variable power or speed mechanism in a structure in which the lifting power may be exerted regardless of the position of the steering handle of the truck, which serves also as a means for applying power to the lifting mechanism, and the incorporation in atruck of this character of improved mechanism for transmitting power to the lifting frame, and for controlling the lowering of the lifting frame. The accompanying drawings illustrate the form in which I prefer to embodv the improvements above referred to, but I wish it to be understood that the in vention pointed out in the claims hereinafter made is not to be restricted to the specific constructionillustrated and hereinafter specifically described,- but includes Serial No. 477,158.

such changes or modifications as would ocour to those skilled in the art.

In the accompanying drawings, Fig. 1 is a side view showing in elevation the front end portion of atruck, and in longitudinal vertical section portions of the main and lifting frames;

Fig. 2 is a front elevation, some parts being broken away;

Fig. 3 is an enlarged perspective view of a rocking lever which constitutes part of the lifting mechanism;

Fig. 4 is a partial vertical section, onlarged, on line 44: of Fig. 2;

F ig. 5 is an enlarged vertical section on line 5-5 of Fig. 1; I I

Fig. 6 is a partial vertical section through the cross-head at the front of the truck showing the king-bolt and the manner in which the steering handle is mounted, the 7 parts being in what for convenience will be termed their normal position, or that in which the steering handle exerts its greatest leverage on the lifting frame;

Fig. 7 is a similar viewshoWing a cl iange'd arrangement in which the steering handle has less leverage but quicker action;

Fig. 8 is a section on lineS-S of Fig. 7; and

Fig. 9 is a perspective view of one of the links between which the lifting handle is mounted.

My improved truck comprises the usual main frame 10 mounted on front and rear wheels. The rear wheels are not shown as they may be arranged in any approved way. Preferably two front wheels 11 are provided which are mountedon an axle 12 journaled in a bearing 13 which is connected with a king-bolt 14 shown in dotted lines in Fig. 2 and in full lines in Figs. 6 and 7. Above the bearing 13 and connected therewith is a horizontal bearing plate 15 on which rests a sleeve 16 which depends centrally from a cross-head l7 and forms a bearing for the up er portion of the kingbolt 14:. I At its opposite ends the cross-head 17 carries pivoted links 18 which extend upwar and iearwardly and are pivotally connected with laterally-projecting studs 19 provided at opposite sides of the, forward end portion of the usual lifting frame 20. Similar links are providedat the rear end of the lifting frame to conne t it with the main frame, the arrangement being such that by pulling forward on the lifting frame it will be moved forward and upward by the swinging of said links in a' clockwise direction as viewed in Fig. 1. The struc ture as thus far described is oldand is not claimed separately.

The truck is steered by means of a steering handle 21 in the form of a lever which is mounted upon an arm 22 secured to the upper end portion of the king-bolt 1t and overlying the upper. surface of the crosshead. 17', which is extended forward to provide a bearing support for said arm, as shown at 23 in Fig. 7. The arm 22 extends fern-11rd from the kingebolt 1.4: and carries an upright yoke 24: between the arms of which the lower end portion of the handle 21 is fitted, and upon which it is adapted to be fulcrumed, as will behereinafter described. Immediately back of the members of the yoke 2% are blocks 25 the function of which will be hereinafter described. Journaledbetween the arms of the yoke 24 are two links 26 which are preferably provided at their forward ends with bosses 27 which lit in suitable bearings in the arms of the yoke '24 and are provided with alined perforations adapted to receive a pin 28, as shown in Fig. 8. The links26 extend .rearwardly from the yoke 21 and are provided adjacent to their rear ends with alined perforations adapted to receive a pivot 29, as shown in Figs. 6, 7 and 8. At its lower end the handle 21 is provided with an angularly-disposed extension 30.01 load arm so that said handle is in the nature of a bellcrank lever. At the angle of the handle 21 it ,is provided with a perforation 31 adapted to receive the pin 28 when said perforation is alined with the perforations in the bosses 27, and the extension 30 is also provided with a perforation adapted to aline with the perforations in the rear end portiQliS of the links 26 when the perforation 31 alined with the perforations in the bosses 27. In other words, the two perforations in the handle 27 are the same distance apart between centers as the perforations in the links 26. By this construction it will be evident that by removing the pin 28 the steering handle 21. which serves also as a lifting lever. may be fulcrumed upon the pin-29,,in the manner shown in Fig. 6. or by passing the pin 28 through the perforations in. the bosses and the perforation 31 in the steering handle in the manner shown in Figs. 7 and 8 the steering handle may be fulcrumed ,on the yoke 24: turning about the axis of the bosses 27. In the former arrangement the links 26 will drop to the position shown in Fig. 6, their rear end portions resting .on the blocks 25, the upper ends of which are bevelled as shown in Fig. 7, but when the steering handle is fulcrumed on the. y ke 2% the link .26 w ll e alined ith.

the extension 30 of the steering handle and will swing with it about the axis of said links when it is actuated. At its rear end the extension 30 or load arm carries an antifriction roller 32, shown in Figs. (3 and 8, and it will be evident from the foregoing description that by the construction described the effective length of the load arm 30, i. e., from-the roller 32 to the fulcrum of the lifting lever, may be varied by an amount equal .to the length of the links 26 without moving said lever toward or from the load and so altering its relation thereto. \V hen greater power is required the pin 28 is removed and the lifting lever or steering handle 21 is fulcrumed upon the pin 29, whereas when less power is needed and greater speed is desired the pin 28 is applied in the manner shown in Figs. 7 and .8 so

that the steering handle is then .fu'lcrumed upon the yoke 24-. These adjustments do not in any way interfere with the use of the steering handle in steering the truck, as, regardless of the fulcrum point of said handle, it may be swung from side to side to turn the king-bolt 14 and through it the wheel or wheels in the usual manner.

The lifting frame 20 is drawn forward and raised in the illustrated construction by means of two cables 33, best shown in Figs. 1 and 2, the rear ends of which are connected in any suitable way as by means of yokes 34 with the forward portion of said frame. The forward end of one of said cables extends around and is connected with a cam-shaped pulley 35 which is loosely mounted upon a transverse shaft 36 supported by standards 87, 38 rising at opposite sides of the main frame 10, as best shown in F igs. 1 and 5. The pulley 35 is so arranged that by rocking it in a counterclockwisedirection as viewed in Fig. 1 it will wind up the cable thereby drawing the lifting frame forward and at the same time causing it to be lifted through the instrumentality of the links 18, the disposition of the cam being such that said cam has the greatest leverage at the beginning of the lifting movement. v

As best shown in Fig. 5, the hub of the cam 35 is provided with a short lateral extension 39 at one side and with a long lateral extension d0 at the opposite side. At the latter side of the cam it is provided with a friction disc 41, which may either be formed separately and secured fixedly thereto, as shown, or may be formed integral therewith. The hub extension 40 is smooth for a short distance adjacent to the cam and on the smooth portion thereof are mounted a fiber disc 42 which bears against the friction disc 41, and a holding ratchet wheel 43 which bears against the opposite side of the fiber disc 42. At the right of the ratchet wheel {L3, according to-the illustration in Fig. 5

the hub of the cam 35 is provided with screw threads 35, and mounted upon such threads is a second ratchet wheel 44. Between the ratchet wheels 43, 44 is a fiber disc 45. It will be apparent from the foregoing description that by rotating the ratchet wheel 44 upon the hub of the cam 35 in the proper direction the fiber discs 42, 45 may be compressed between the surfaces on which they bear, thereby frictionally securing all of said parts together after the manner of a friction clutch. Consequently rotation of the ratchet wheel 44 in the manner described will operate to rotate the cam 35 in the same direction. Rotation of the ratchet wheel 44 in the opposite direction will release the clutch mechanism, thereby permitting the cam 35 and its hub to rotate in the opposite direction, which will cause the ratchet wheel 44 to be again screwed up on said hub, as the ratchet wheel 44 will in the meantime be held against rotation by friction between said ratchet wheel, the friction disc 45, and the holding ratchet wheel 43. The clutch mechanism will therefore again become effective and will stop the reverse rotation of the cam 35 after it has moved a short distance. To permit said cam to continue its reverse rotation it is therefore necessary to further rotate the ratchet wheel 44 in a reverse direction, when the same operation will be repeated. The parts are so designedthat by rotating the ratchet wheel 44 in a counterclocking direction as viewed in Fig. 4 the cam 35 will be rotated in the same direction, thereby raising the lifting frame, and by reversely rotating theratchet wheel 44 intermittently the cam 35 will be permitted to rotate in the opposite direction intermittently to lower the lifting frame. The function of the ratchet wheel 43 is to hold the lifting frame in position except when the lifting mechanism is actuated, and as it need never rotate in a reverse direction it is held against such rotation by a pawl 46 which is mounted on a transverse shaft 47 carried by the standards 37 38 and is held in engagement with the ratchet wheel 43 by a spring 48 shown in Fig. 5. Where two cables 33 are used a second cam pulley 49 similar to the pulley 35 is provided, which is mounted on and keyed to the hub extension 40 adjacent to the ratchet wheel 44, as shown in Fig, 5. \Vhile I prefer to use two cam pulleys the pulley 49 may be dispensed with without materially affecting the operation offthe lifting mechanism.

The ratchet wheel 44 is operated in either direction by means of a reversible pawl 50 best shown in Figs. 1 and 4. This pawl, which is provided with oppositely-disposed dogs 51, 52, is mounted on a pivot 53 carried by a lever frame 54 which is loosely mounted upon the end portions of the two hub extensions 39, 40, as shown in Fig. 5. This lever frame is substantially triangular in outline, being provided with an upwardlyextending arm 55 in which is mounted a cross-rod 56, and a forwardly-extending arm 57 in which is mounted a cross-rod 58, as best shown in Fig. 4. The latter crossrod carries an anti-friction roller 59 which overlies the roller 32 carried by the load arm of the steering handle 21, as shown in Fig. 1. 60 indicates a link connected with the steering handle 21 by a pivot 61 and having a notch 62 in its outer end adapted to engage the cross-rod 56, as shown in Fig. 1. The link 60 may be held out of operative position by a hook 63 pivoted upon the steeling handle 21, as shown in said figure.

The operation of the mechanism described is as follows :-Assuming that the parts are in the position shown in full lines in Fig. 1, by swinging the upper end of the steering handle 21 forward its rearward extension 30 or load arm will operate to rock the lever frame 54, which represents the load, in a counterclockwise direction as viewed in said figure. The tooth 51 of the pawl 50 being then in engagement with the ratchet wheel 44, said ratchet wheel will accordingly be rotated in the same direction, thereby screwing it up on the hub extension 40 and tightening up the clutch mechanism As the steering handle 21 is rocked back and forth this rotation of the ratchet wheel 44 will be continued until, the clutch mechanism having become effective, the cam pulley 35 is rotated sufficiently to raise the lifting platform to the desired height. During the lifting operation the holding pawl 46 will prevent reverse movement of said cam pulley. The leverage of the steering handle 21 upon the load, or lever frame 54 depends upon the fulcrum point of said handle, which, as has been described, may be adjusted at the pleasure of the operator. Then the greatest leverage is used the ratchet wheel 44 is ordinarily rotated one notch at a time so that the load rises slowly. but if the arrangement shown in Figs. 7 and 8 is employed each movement of the steering handle will effect a greater movement of the lever frame so that the ratchet wheel 44 will then be moved several notches at each stroke. If the load to be lifted isvery light and it is desired to raise the lifting platform very quickly, the link 60 may be connected with the rod 56, whereupon one or two strokes of the steering handle in a reverse direction will suffice to completely elevate the lifting frame. My improved construction, therefore, provides three speeds at which the lifting platform may be elevated, so that it'is well adapted to meet the vary: ing conditions encountered in the practical use of the truck.

To lower the lifting frame the lever frame 54 is swung over to a position shown in dotted lines in Fig. 1, and the pawl is also reversed, so that a forward stroke of the steering handle, which is then connected with the lever frame 54: by hooking the link over the pin 56, will operate to rotate the ratchet wheel 44. in a clockwise direction as viewed in Fig. 1. This unscrews said ratchet wheel and consequently releases the clutch mechanism sufliciently to permit the Weight of the load to rotate the cam pulley 35 in a clockwise direction, but as this again tightens up the clutch mechanism in the manner above described, the downward movement of the lifting frame will stop as soon as the clutch becomes effective, necessitating a further reverse movement of the ratchet wheel 4:4. In practice, however, the result is substantially a continuous de scent of the lifting frame. During the lowering operation the link 60 is connected with the pin 56, as not much leveragsis required to operate the ratchet wheel 44; at this time. When the lifting frame is being lowered the clutch. mechanism acts as a brake to cushion'its descent, as it becomes effective gradually, and, therefore, the descent of the load is stopped without shock.

What I claim as my invention and desire to secure by Letters Patent, is-

1. A lifting truck comprising a main frame, a lifting frame, a'steeri'ng and liftlng lever, means adapted to be actuated by said lever to raise said lifting frame, and means independent of movement of said lever toward or from the load for shifting the fulcrum point thereof to vary the power required to lift a given load on said lifting frame.

2. A lifting truck comprising a main frame, a lifting frame, a steering wheel, a steering lever connected with the steering wheel, mechanism adapted to be actuated by said steering lever for raising said lifting frame, and means independent of movement of said lever toward or. from said mechanism for adjusting the fulcrum point of said lever to vary the leverage thereof effective to lift a given load on said lifting frame.

' 3. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, an operating lever, and means for varying the leverage of said lever effective to lift a given load on said lifting frame, comprising a support, and a swinging member mounted on said support, said lever being adapted to be fulcrumed on said member at a point removed from the axis thereof or, alternatively, to swing about such axis.

4. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, an operating l ve an mea s for varying the leverage of said lever effective to lift a given load on said lifting frame, comprising a sup port, and a vertically movable member pivoted on said support, said lever having a fulcrum connection with said member at a point removed from the axis thereof and being adapted to be connected with said member to swing therewith.

5. A lifting truck comprising a main frame, a lifting frame, a steering handle operable from its different steering positions to raise the lifting frame, and means for adjusting the fulcrum of said handle to vary the leverage thereof eflective to lift a given load'on said lifting frame.

6. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, a steering handle operable from its different steering positions to actuate said lever-actuated mechanism, and means for adjusting the fulcrum of said handle to vary the leverage thereof effective to lift a given load on said lifting frame.

7. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, an operating lever, and means at opposite sides of the fulcrum of said operating lever adapted for alternative use to actuate said leveractuated mechanism.

8. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, an operating lever, and a plurality of fulcra for said operating lever at different distances from said lever-actuated mechanism adapted for alternative use.

9. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, an operating lever, a link pivotally supported by said main frame and pivotally connected with said operating lever, forming a fulcrum therefor, and a sepa'ate fulcrum for said lever concentric with the pivotal sup port of said link.

10. A lifting truck comprising a main frame, a lifting frame, lever-actuated mechanism for raising said lifting frame, a kingbolt mounted in said main frame, a standard connected with said king-bolt, a link pivot ally mounted on said standard, and a steering handle pivotally connected with said link and adapted to be fulcrumed on said standard concentrically with the pivot of said link.

11. A lifting truck comprising a main frame, a lifting frame, friction clutch devices operable to raise the lifting frame,a ratchet wheel for actuating said devices, and a lever for actuating said ratchet wheel.

12. A lifting truck comprising amain frame, a lifting frame, friction clutch devices operable to raise thelift-ing frame, a

ratchet wheel for actuating said devices, and a lever operable from its different steering positions to actuate said ratchet wheel.

18. A lifting truck comprising a main frame, a lifting frame, a rotary member adapted by its rotation to raise the lifting frame, friction clutch devices operable to rotate said member, a ratchet wheel for actuating said devices, and a lever for actuating said ratchet wheel.

14. A lifting truck comprising a main frame, a lifting frame, a rotary member adapted by its rotation to raise the lifting frame, friction clutch devices operable to rotate said member, a ratchet wheel for actuating said devices, and a leveroperable from its difi'erent steering positions to actuate said ratchet wheel.

15. A lifting truck comprising a main frame, a lifting frame, an operating lever, a rotary member adapted by its rotation to raise the lifting frame and having a screwthreaded hub, a ratchet wheel mounted on the threads of said hub, friction clutch mechanism actuated by movement of said ratchet wheel on said threads for actuating said rotary member, and means operated by said operating lever for rotating said ratchet wheel.

16. A lifting truck comprising a main frame, a lifting frame, an operating lever, a rotary member adapted by its rotation to raise the lifting frame and having a screwthreaded hub, a ratchet wheel mounted on the threads of said hub, friction clutch mechanism actuated by movement of said ratchet wheel on said threads for actuating said rotary member, means operated by said operating lever for rotating said ratchet wheel, and means for preventing reverse rotation of said rotary member during the lifting operation. a

17. A lifting truck comprising a main frame, a lifting frame, an operating lever, a rotary member having a screw-threaded hub, a ratchet wheel mounted on the threads of said hub, friction clutch mechanism loosely mounted on said hub between said rotary member and said ratchet wheel and operated by longitudinal movement of said ratchet wheel upon said hub, and means operated by said operating lever for rotating said ratchet wheel.

18. A lifting truck comprising a main frame, a lifting frame, an operating lever,

a rotary member having a screw-threaded hub, a ratchet wheel mounted on the threads of said hub, friction clutch mechanism loosely mounted on said hub between said rotary member and said ratchet wheel and operated by longitudinal movement of said ratchet wheel upon saidhub, means operated by said operating lever for rotating said ratchet wheel, a holding ratchet wheel loosely mounted on said hub between said rotary member and said firstmentioned ratchet wheel, and a holding pawl engaging said holding ratchet wheel for preventing reverse rotation of said rotary member during the lifting operation.

19. A lifting truck comprising a main frame, a lifting frame, an operating lever,

a rotary member mounted on said main frame, a flexible connection between said rotary member and said lifting frame, whereby rotation of said rotary member will operate to raise or lower said lifting frame, a screw-threaded hub connected with said rotary member, a ratchet wheel mounted on the threads of said hub, friction clutch mechanism. loosely mounted on said hub between said rotary member and said ratchet wheel, a rocking lever pivotally mounted to swing about the axis of said rotary member, a reversible pawl carried by said rocking lever and adapted to operatively engage said ratchet wheel, and means whereby said rocking lever may be rocked by the operation of said operating lever.

20. A lifting truck comprising a main frame, a liftino' frame, an operating lever, a rotary mem er mounted on said main frame, a flexible connection between said rotary member and said lifting frame, whereby rotation of said rotary member will operate to raise or lower said lifting frame, a screw-threaded hub connected with said rotary member, a ratchet wheel mounted on the threads of said hub, friction clutch mechanism loosely mounted on said hub between said rotary member and said ratchet wheel, a rocking lever pivotally mounted to swing about the axis of said rotary member, a reversible pawl carried by said rocking lever and adapted to operatively engage said ratchet wheel, and means at opposite sides of the fulcrum of said operating lever adapted to be used alternately for rocking said rocking lever.

ARTHUR M. BARRETT.

Certificate of Correction. It is hereby certified that in Letters Patent No. 1,528,749. ranted March 10,

, a 1925, upon the applioation of Arthur M. Barrett, of Vinnetka, Illinois, for an improvement in Lifting Trucks, an error appears in the printed specification requiring correction as follows: Page 5, line 1.08, claim 20, for the Word alternately" read alternatively; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 31st day of March, A. D. 1925.

[SEAL] KARL FENNING,

Acting Commissioner of Patents,

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