US1867826A - Pedal actuated elevating truck - Google Patents

Description

July 19, 1932. D. E. HENNESS PEDAL ACTUATED ELEVATING TRUCK Filed Feb. 7, 1930 @w om 2w, w www P a InvenToT: Daniel EHennessy ywawkf v Aflys.

Patented July 19, 1932 UNITED STATES PATENT OFFICE DANIEL E. HENNESSY, OF WATERTOWN, MASSACHUSETTS, ASSIGNOR TO LEWIS-SHEP- .ARD COMPANY, OF WATER-TOWN, MASSACHUSETTS, A CORPORATION OF MASSA CHUSETTS PEDAL ACTUATED ELEVATING TRUCK Application filed February 7, 1930. Serial No. 426,509.

This invention relates to improvements in elevating trucks provided with lifting mechanism for the load-supporting means operable by a foot lever so positioned as to enable the operator to project his full weight upon it, whereby the initial lifting force applied by the momentum of his full weight to start the lifting mechanism from a position of rest will greatly exceed that which would be produced by the static application of his weight to the foot lever, as disclosed in my prior application Serial Number 37 2,372, filed June 20, 1929, and the general object of the present invention is to provide a construction in which the multiplication of power applied by the foot lever will be greater than that heretofore attained, thereby facilitating the lifting operation.

The present invention is applicable to an elevating truck comprising a wheel-supported frame, load-supporting means and means operable to raise the load-supporting means longitudinally relatively to'the frame, and one of the objects of the invention is to provide a pawl movable bodily with the loadsupporting means operable by a foot lever mechanism having pawl-engaging and actuating means movable through an are having a relatively short radius and operable to move the load-supporting means longitudinally and thereby raise the same.

A further object of the invention is to provide a construction in which the pawlactuating means will be maintained out of operative relation with the pawl when the foot lever is in raised position.

A further object of the invention is to provide a mechanism of this character comprising a pawl having a series of teeth adapted to be engaged by the pawl-actuating mechanism of the foot lever to raise the load-supporting means step by step, with means to lock the load-supporting means at each step of elevation.

A further object of the invention is to provide means for maintaining the pawl out of operative relation to the pawl-actuating means during the descent of the load-supporting means, a suitable relief check desirably being provided to cushion the descent of the load-supporting means.

Another object of the invention is to provide a novel and economically constructed head for the main frame adapted to permit the steering post of the steering mechanism to be journalled therein.

These and other objects and features of the invention will more fully appear from the following description and the accompanying drawing and will be particularly pointed out in the claims.

A preferred embodiment of the invention is shown in the accompanying drawing, in which,

Fig. 1 is a plan view of an elevatingtruck embodying the invention.

Fig. 2 is a side elevation of the same.

Fig. 3 is a detail sectional view on line 33, Fig. 1.

Fig. 4 is a detail sectional view on line 4--4, Fig. 1.

The frame of the elevating truck, as illustrated herein, comprises parallel side bars 1 and 2, which may be made of flat bar stock, supported at their rear ends upon an axle 3 having wheels 1, preferably located outside of the frame, with guard plates 5 connected, preferably by welding, to the side bars 1 and 2 and presenting inclined surfaces adapted to prevent the wheels from being engaged by any obstacle. The front ends of the side bars 1 and 2 are connected by a head which may comprise vertical plates 6 and 7 secured to the side bars 1 and 2 by rivets 8, or by lines of welding 9, or both.

The upper ends of the vertical plates are connected by a girder comprising a channel bar 10 welded at its ends to the plates 6 and 7 with its flanges 1 extending upwardly and a complementary reversely arranged channel bar 12 having its flanges 13 overlapping and preferably fitting within the flanges 11 of the channel bar 10, the channel bars being secured together to form a box-like girder preferably by the welding of the flanges 11 and 13 together. The upper channel bar 12 likewise is welded at its ends to the vertical plates 6 and 7. The girder thus formed desirably is provided centrallv with alined apertures in which the steering post 14 of the usual steering head is journalled. The steering post 14 extends upwardly from the central portion of a yoke 15 having clownwardly extending arms 16 provided at their lower ends with bosses in which the shaft 17 of the steering wheel or wheels 18 is journalled.

The steering post 14 has secured to its upper end a split collar 19 having upwardly extending bosses 20 in which the pivotal shaft 21 of the steering tongue 22' is journalled. The lower end of the steering tongue is provided with an extension 23 adapted, when the steering tongue is swung about its pivot slightly beyond vertical position, to engage the upper end of the collar 19 and thereby to hold the steering tongue in raised position, and also to permit the truck to be pushed rearwardly by force applied to the steering tongue. It also enables the steering tongue to be maintained in a position in which the operator may grasp it and steady himself as he projects his weight upon the lifting lever or pedal as will hereinafter be described. I

A preferred form of load-supporting means, which is illustrated herein, comprises preferably longitudinally extending angle bars 24 and 25, the horizontal webs of which extend inwardly and the vertical webs of which preferably are movable vertically within and closely adjacent to the side bars 1 and 2. The rear ends of the angle bars desirably are connected by an angle bar or channel bar girder 26 which is seated in recesses formed by cutting away the horizontal flanges of the angle bars and which is welded to the vertical flanges of the angle bars 24 and 25 and which preferably is of such length as to extend to the plane of the outer faces of the wheels 4. The ends of this girder desirably are curved, as illustrated, in such a manner as to avoid a sharp corner.

The front ends of the angle bars 24 and 25 of the load-supporting means are connected by a head of forged or cast metal comprising a transverse girder 27 which is welded, or otherwise secured, to the ends of the angle bars 24 and 25 and is provided with a vertical member or flange 28 forming a dash board at the front end of the load-supporting means. Desirably integral bosses 29 and 80 extend forwardly from the central portion of the vertical member or flange 28 and are provided near their ends with a transverse shaft 31 which is pivotally connected to bosses 32 extending upwardly from the piston of a substantially vertical dash pot 33, the lower end of which is pivotally mounted upon a shaft 34 extending transversely of the frame and mounted in the side bars 1 and 2 thereof.

The load-supporting means is supported upon the frame in such a manner that forward longitudinal movement thereof relatively to the frame will raise the load-supporting means. As illustrated in the drawing the means for supporting the load-supporting means is in the form of parallel links, the rear end of the platform being supported upon a pair of links 35 which are journalled at their lower ends upon the rear axle 3 and are spaced apart by a sleeve 36, while the upper ends of said links are pivoted upon a shaft 37 which is mounted in the vertical webs of the angle bars 24 and 25' of the load-supporting means and are spaced apart by a sleeve 38.

The ront end of the load-supporting means is supported by parallel links 39 and 40 which preferably are of sector-shape, the lower or narrower ends of said links being pivotally mounted upon the shaft 34 which supports the dash pot, and the upper and rearward portions of the sector-shaped links being provided with laterally extending studs 41 which engage complementary sockets in plates 42 which are Welded, or other wise connected, to the vertical webs of the angle bars 24 and 25 of the load-supporting means and constitute continuations thereof.

The extensions 42 overlie the sidebars l and 2 and when the load-supporting means is in lowered position rest upon the same as illustrated in Fig. 2.

The mechanism for raising the load-supporting means comprises a pawl which is bodily movable with the load-supporting means and is adapted to be engaged by a pawl-actuating member operated by a foot pedal which, when depressed, will move the pawl and load-supporting means longitudinally relative to the main frame and consequently cause the parallel links to raise the load-supporting means.

Preferably a plurality of pawls are provided arranged u 301] opposite sides of and symmetrically wit 1 respect to the longitudinal axis of the truck, with pawl-actuating means for simultaneously engaging and actuating the pawls, thereby avoiding the imposition of racking strains upon the frame and load-supporting means during the lift ing operation.

Desirably each pawl is provided with a series of teeth adapted to be engaged by the respective pawl-actuating means upon successive depressions of the foot lever and means are provided for releasably locking the load-supporting means at each step of elevation.

Any suitable means may be provided to accomplish this purpose. In the preferred construction illustrated pawls 43 are pivotally mounted upon studs 44 extending inwardly from the sector-shaped links which connect the front end of the loadsupporting means and frame. The studs 44 are located near the forward edge of the sectorshaped links in such position that as the til links are swung to move the load-supporting means from lowered to elevated position the studs 44 will swing through approximately horizontal arcs, as distinguished from the more inclined arcs through which the studs 41, which connect the front links to the loadsupporting means, swing during the same movement, thereby enabling power to be transmitted to the parallel links to swing them about their fulcrums more uniformly and effectively than if the power were applied to the upper pivots of the links. Furthermore, the radius, upon which the pivots 44 of the pawls 43 are swung, desirably is shorter than the effective length of the link,

thereby enabling the links to be swung from lowered to raised position with a shorter forward movement of the pawl. By reason of this construction pawl-actuating means may be employed which are movable through a very short radius relatively to the effective length of the foot lever and a lifting leverage obtained which will enable a heavy load to be lifted easily.

The foot lever, or other lifting lever, may be provided with any suitable means for actuating the pawl in the manner above described. In the preferred construction illustrated herein a foot lever 46, having a pedal 47, preferably located in proximity to the head of the truck, is keyed or otherwise rigidly secured to a transverse shaft 48, which is journaled in the side bars 1 and 2 of the main frame. The shaft 48 has mounted upon it and rigidly secured to it a sleeve 49 having at its ends enlarged cylindrical bosses 50 which are recessed to provide shoulders 51 adapted to engage the teeth 45 of the respective pawls 43.

Suitable means are provided for normally maintaining the foot lever in raised position. The preferred means illustrated in the drawing comprises a spring coiled in opposite directions from its center with the coils 52 and 53 thereof surrounding the sleeve, and with the central portion 54 anchored to a suitable boss 55 extending from the sleeve, the ends 56 and 57 of the coils being anchored to the side bars 1 and 2 respectively. The spring is under sufficient tension normally to maintain the pedal in raised position.

The bosses 50 of the sleeve 49 are recessed in such a manner that when the foot pedal is in raised position the shoulders 51 are so positioned and inclined with respect to the pawls as not to be effectively engaged by the teeth of the pawl, but when the foot lever is depressed a slight rotation of the sleeve will bring the shoulders into effective engagement with the corresponding teeth of the respective pawls and continued depression of the foot lever will cause said shoulders to move the pawls forwardly in the manner above described.

It will be understood that the parts may be so proportioned that the load-supporting means may be moved from lowered to raised position by a single depression of the foot lever, in which case the shoulder may engage only a single tooth upon each pawl or the end of the pawl itself. Preferably, however, the pawls are provided with a plurality of teeth to enable the load-supporting means to be raised step by step, and suitable looking means are provided for retaining the load-supporting means at each step of elevation, while the foot lever is released and raised by the spring to position the pawl-actuating means for engagement with the next succeeding tooth upon the next depression of the foot lever.

Any suitable locking means may be provided. In the preferred construction illustrated the front parallel link 40, which is of sector shape as above described, is provided with a series of teeth 58 complementary to the teeth upon the pawls. A locking dog 59, having a hooked end to engage the respective teeth 58, is secured to a short rock shaft 60 which is mounted in suitable bosses 61 upon the head of the machine. An arm 62, which is connected to the rock shaft 60, extends forwardly and is provided at its free end with a pedal 63 which is located in a conveniently operated position.

In operation, the elevating truck with the load-supporting means in lowered position, is backed beneath the load, which ordinarily is supported upon a portable platform. The foot lever is then depressed by the operator who may, by steadying himself by the upraised tongue 22 of the truck, project his full weightuponthe pedalthereof,thereby applying an initial lifting force greatly exceeding that which would be produced-by the static application of his weight to the pedal. The depression of'the foot lever rotates the rock shaft 48 and the sleeve which is connected thereto against the tension of the spring and brings the shoulders 51 into engagement with teeth 45 upon the pawls 43. Continued downward movement of the pedal forces the pawl longitudinally bodily thereby rotating the parallel links forwardly and consequently raising the platform.

When the foot pedal has been depressed to its lowest position, in which it may contact with the floor if not otherwise restrained, the locking dog 59 engages a tooth 58 upon the link 40, thereby holding the load-supporting means at the first step of elevation. The operator may then release the pedal, thereby permitting the spring to restore'it to normal raised position, and the operation repeated successively to raise the load-sup- I-i,

porting means to its full height. The loadsupporting means may then be transported to its destination by usual manipulation of the tongue. The operator will then step upon the pedal 63 of the locking dog, thereby disengaging it from the tooth 58 of the link 40, thus permitting the load-supporting means to descend. The descent of the load-supporting means is cushioned by the action of the dash pot 33 in the usual manner.

It will be remembered that when the foot lever 46 is in normal raised position the pawlactuating shoulders 51 are so ositioned that the teeth of the pawl cannot er ectively engage them during the descent of the platform.

If desired, however, other means may be provided for maintaining the pawls in raised position in which they cannot engage the bosses upon the sleeve during the descent of the load when the pedal is in its normal raised position. This may be accomplished by providing the sleeve 49 with forwardly extending arms 64 provided with offset ends or studs 65 underlying the pawls 43 and acting when the sleeve is rotated by its spring, in a direction to raise the foot lever, to lift and maintain the pawls out of engagement with the bosses 50 of the sleeve 49.

It will be understood that the particular embodiment of the invention disclosed herein is of an illustrative character and is not restrictive, and that various changes in form, construction and arrangement of parts may be made within the spirit and scope of the following claims.

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

1. An elevating truck comprising a frame, load-supporting means, means operable to raise said load-supporting means upon longitudinal movement thereof, a pawl movable bodily with said load-supporting means, a foot lever fulcrumed on said frame, and pawlactuating means operable by the depression of said foot lever to engage and move said pawl in a direction longitudinally of said frame and thereby to raise said load-supporting means.

2. An elevating truck comprising a frame, load-supporting means, means operable to raise said load-supporting means upon longitudinal movement thereof, a pawl movable bodily with said load-supporting means, a foot lever fulcrumed on said frame, pawlactuating means operable by the depression of said foot lever to engage and move said pawl in a direction longitudinally of said frame and thereby to raise said load-supporting means, releasable means for locking sait load-supporting means in raised position, and means tending to move said foot lever to raised position and said pawl-actuating means out of operative relation to said pawl.

3. An elevating truck comprising a frame, load-supporting means, means operable to raise said load-supporting means upon longitudinal movement thereof, a pawl movable bodily with said load-supporting means, a foot lever fulcrumed on said frame, pawlactuating means operable by the depression of said foot lever to engage and move said pawl in a direction longitudinally of said frame and thereby to raise said load-supporting means, releasable means for locking said load-supporting means in raised position, means tending to move said foot lever to raised position and said pawl-actuating means out of operative relation to said pawl, and means movable with said foot lever positioned to engage said pawl when the foot lever is in raised position and maintain said pawl out of operative relation to said pawlactuating means.

4%. An elevating truck comprising a frame, load-supporting means, means operable to raise said load-supporting means upon longitudinal movement thereof, a pawl provided with a plurality of teeth movable bodily with said load-supporting means, a foot lever fulcrumed in said frame having pawl-actuating means operable upon depression to engage a tooth of said pawl and move said pawl in a direction. longitudinally of said loadsupporting means, releasable means for locking said load-supporting means at each step of elevation, and means tending to move said foot lever to raised position and to position said pawl-actuating means out of operative relation to said pawl.

5. An elevating truck comprising a frame, load-supporting means, means operable to raise said loadsmpporting means upon longitudin al movement thereof, pawl provided with a plurality of teeth movable bodily with said loadsupporting means, a rock shaft join-nailed in said frame having a foot lever and a pawl-actuating shoulder movable upon successive depressions of said foot lever into actuating engagement with successive teeth of said pawl to raise said 1021 d-supporting moans step by step, releasable means for locking said load-supporting means at each step of elevation, and means for preventing effective engagement of said shoulder and said pawl upon descent of said load-supporting means when released.

6. An elevating truck comprising a frame, load-supporting means, means operable to raise said lead-supporting means upon longitudinal movement thereof, a pawl provided with a plurality of-teeth movable bodily with said load-supporting means, a rock shaft journalled in said frame having a foot lever and a pawl-actuating shoulder movable upon successive depressions of said foot lever into actuating engagement with successive teeth of said pawl to raise said load-supporting means step by ste releasable means for looking said load-supporting means at each step of elevation, resilient means operable to rotate said reel: shaft in a direction to restore said foot lever to raised position and to move said pawl-actuating shoulder out of operative relation with the teeth of said pawl.

7. An elevating truck comprising a frame, load-supporting means, means operable to raise said load-supporting means upon longitudinal movement thereof, a pawl provided with a plurality of teeth movable bodily with said load-supporting means, a rock shaft journalled in said frame having a foot lever and a pawl-actuating shoulder movable upon successive depressions of said foot lever into actuating engagement with successive teeth of said pawl to raise said load-supporting means step by step, releasable means for locking said load-supporting means at each step of elevation, a spiral spring encircling said rock shaft and connected thereto and to said frame operable to rotate said rock shaft in a reverse direction to restore said foot lever to raised position and to move said pawl-actuating shoulder out of operative relation to the teeth of said pawl.

8. An elevating truck comprising a frame, load-supporting means, parallel links connecting said load-supporting means to said frame operable to raise the load-supporting means upon longitudinal movement thereof, a pawl pivotally supported on one of the front links to swing through a substantially horizontal are, a rock shaft journalled in said frame underlying the end of said pawl and having a shoulder movable into operative engagement with said pawl, a foot lever connected to said rock shaft operable upon de pression to cause the shoulder upon said rock shaft to actuate the pawl and thereby move the load-supporting means longitudinally of said frame, means tending to raise said foot lever and rotate said shoulder out of operative relation to said pawl, and means for locking said load-supporting means in elevated position.

9. An elevating truck comprising a frame, load-supporting means, parallel links connecting said load-supporting means to said frame operable to raise said load-supporting means upon longitudinal movement thereof, a pawl pivot-ally supported on one of the front links to swing through a substantially horizontal arc and having a toothed lower face, a rock shaft ournalled in said frame underlying the toothed portion of said pawl and having a shoulder movable successively into operative engagement with the respective teeth of said pawl, a foot lever connected to said rock shaft operable upon successive depressions to cause the shoulder on said rock shaft to engage successive teeth of said pawl vand by actuation thereof to raise said loadsupport-ing means step by step, means for locking said load-supporting means at each step of elevation, and means tending to rotate said rock shaft in a reverse direction and thereby raise said foot lever and rotate said shoulder out of operative relation to said pawl.

10. An elevating truck comprising a frame,

load-supporting means, parallel links connecting said load-supporting means to said frame operable to raise said load-supporting means upon longitudinal movement thereof, a pawl pivotally supported on one of the front links to swing through a substantially horizontal are and having a toothed lower face, a rock shaft journalled in said frame underlying the toothed portion of said pawl and having a shoulder movable successively into operative engagement with the respective teeth of said pawl, a foot lever connected to said rock shaft operable upon successive depressions to cause the shoulder on said rock shaft to engage successive teeth of said pawl and by actuation thereof to raise said loadsupporting means step by step, means for locking the load-supporting means at each step of elevation comprising a toothed looking dog and complementary teeth upon the other front link and a pedal connected to said dog operable when depressed to release the same, and means tending to rotate said rock shaft in a reverse direction to raise said foot lever and to move said shoulder out of operative relation to said pawl.

11. An elevating truck comprising a frame, load-supporting means, means operable to raise the load-supporting means upon longi tudinal movement thereof, pawls movable bodily with said load-supporting means and located upon opposite sides of and symmetrically in relation to the longitudinal axis of said truck, a rock shaft journalled in said frame underlying the ends of said pawls and having shoulders movable into operative engagement with said pawl, a foot lever con nected to said rock shaft operable upon depression to cause the shoulders upon said rock shaft to actuate said pawls and to exert a lifting force symmetrically with respect to the axis of the truck thereby avoiding racking strains, and means for locking the loadsupporting means in elevated position.

In testimony whereof, I have signed my name to this specification.

DANIEL E. HENNESSY.

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