US1769995A - Elevating truck - Google Patents

Description

y 1930. Q D. 1 HENNESSY 1,769,995 9 ELEVATING TRUCK Filed July 23, 1929 2 Sheets-Sheet 1 Fig. 3 29 33 l4 I3 10 an G Fl a g l lnvenTor. Daniel E.Pitannecasy AYTys.

July 8, 1930. ss 1,769,995

ELEVAT IIIIII CK Filed July 23, 1929 2 Sheets-Sheet 2 lnvenTor.

Daniel E. Hennessy b MMl M 1 Anya.

Patented July 8, 1930 maransrares PATENT OFFICE" DANIEL E. HENNESSY, or wATERTowN, MASSACHUSETTS, Ass'IeNoR To LEWIS-SHEP- ARI) COMPANY, or WATERTOWN, MASSACHUSETTS, A CORPORATION or MASSACHU- SETTS 1 ELEVATING TRUCK App1ication filed Ju1y23,

This invention relates to improvements in elevating trucks comprising a frame and load supporting means connected by parallel links to said framewith means for raising the load supporting means relatively to the frame, whereby the parallel links will cause the load supporting means to move longitudinally relatively to the frame during the raising and lowering movement, and the princilt pal object of the invention is to provide novel locking means for retaining the load supporting means in elevated position which can be readily released to permit the descent of the load.

The locking mechanism for elevating trucks of this type usually comprises interengaging hook-shaped members which can be disengaged only by the application of considerable force and frequently such locking 2@ members become broken.

In the present construction the locking mechanism comprises a shaft which is rotatably mounted on the load supporting means and a co-operating dog having a shoulder to engage said shaft when in looking position. Means are provided to rotate the shaft in a direction to cause the rolling engagement between said shaft and said shoulder to release the locking means. In order to insure positive locking of the load supporting means in elevated position the locking dog is so pivoted that the arc of movement of the shoulder thereof intersects the arc of movement of the shaft caused by the parallel links, so that when the parts are engaged relative longitudinal movement of the load supporting means is positively prevented until the shaft is rotated.

A further object of the invention is to provide an elevating truck comprising a frame and steering mechanism having a tongue mounted to swing vertically, with load supporting means mounted on parallel links upon said frame and having an integral lift- 5 ing head overlying the steering mechanism,

and a lifting lever opearble by a vertical swinging movement of the tongue to apply vertically a lifting force to the lifting head in approximately the direction of the axis of the steering mechanism, with means 1929. Serial No. 380,293.

for locking the load supporting means in elevated position, and a vertical dash pot within and protected by said lifting head having its cylinder and piston connected respectively to the frame, and load supporting means operable to cushion the descent of the load upon release of the locking means.

A further object of the invention is to provide a construction in which the locking mechanism and the dash pot, as well as the steering mechanism, are located substantially centrally of the longitudinal axis of the truck, and load supporting means, thereby preventing the application of twisting strains to either. v

These and other objects and features of the invention will more fully appear from the following description and the accompanying drawings and will be particularly pointed out in the claims. 8

' In the drawings: V

Fig. 1 is a perspective view of a truck embodying the invention, viewed from the rear;

Fig. 2 is an enlarged perspective view of the,i front end port-ion of the elevating truck; an 7 it i is a detail view, partly in vertical longitudinal section, illustrating particularly the lifting mechanism, locking mechanism, and the dash pot. H

The elevating truck embodying the present invention, as illustrated in the drawings, comprises a frame having a preferably integral head composed of arched members 1 and.2 which are spaced-apart and connected by side members 3. These arched members are connected centrally of the width of the truck by an annular bridge 4 which desirably is integral with the head and in which the steering post of the steering mechanismis mounted.

The steering post is provided with downwardly extending yoke arms 5 having bosses to receive the axle 6 upon which the steering wheels 7 are mounted. A split collar '8- is rigidly clamped upon the upper; end of the steering. post and is. provided with upwardly extending ears 9 in the upperendof which the; pivotal shaft 10 for the steering tongueis mounted. The steerin'g'tongue comprises a curved base member 11 having a jection adapted to be engaged by a cooperating member of a latch 16 which is pivotally mounted upon a shaft 17 extending through the arms 12 of the tongue? When the lifting lever and latchare thus engaged the lifting lever forms injeffe'ct an extension of thetongue, but when the latchis disengaged from the lifting lever the tongue is freed tlierefrom and can be moved vertically without actuating the lifting lever, thus permitting free movement offthe tongue for steeringpurposes. i

The construction of the lifting mechanism above described maybe and desirably is substantialIyJthe same, as that, disclosed in my prior Patent No, 1,741,712, granted Decemhere-1,1929. L a a a a Side bars 18, which are connected to the side members 36f the head 1, extend rearw ardly therefrom in parallelism and at their rear ends are connected by the rear axle 19 of the truck uponwhich ,the rear wheels20 are mounted. i a

The load suppo'rting means comprises side bars 21 which desirably overlie the side bars 18 of the frame and are connectedat their rearendsbyachannel bar 22 and at their front end by an integral lifting head comprising a front arched bar 23" and a rear 7 plate 24 which are connected by side members 25. In proximity to the central longit-udinal axis of the truck, parallel webs 26 and 27 extend upwardly from the plate. 24 to thefrontarch' 23 of the lifting head andare integral therewith, These webs are spaced apartl'sufiicientl'yto provide a chamber for a verticaldash pot, the piston 28 of which is provided with ears29fwhich are pivotally mounted upon aishaft 30 mounted in the webs and;27. Thecyl'inder 31 of the dash potis supported upon and pivotally connectedtola transverse girder 32 0f the main framem 2 By reason of this construction the dash pot is well protected from injury, and islocated in the longitudinal central plane of the truck, so thatWhentheWeightof the'load .is imposed upo n; it, upon release of the locking mechanismptwisting strains will be avoided. "Thefliftirig head :23 "is prowided with a forward-extension 33; which, overlies the axis of the stee ngpostf and has a-flat under me e ee-f e de eblr ,ing mechanism. Therefore, the front end of the load supporting means will be raised,

a and as it is raised will be caused to move longitudinally of the frame by reason of the parallel link connection thereto, so that the fiat face 34 of the lifting head will ride upon the roller 14 during the lifting movement,

thus enabling the lifting force to be applied vertically throughout the entire lifting move- .ment.

The operation of the lifting mechanism is practically the same as that disclosed in my [prior Patent No. 1,741,712 aforesaid.

Gne'of the principal features of the invention relates to easily releasable mechanism for locking the load supporting means in elevated position. In the preferred construction illustrated herein this locking mechanism comprises a shaft which is journalled in hearings in forwardly projecting portions of the wcbs26 and 27 the liftinghead, and also desirably journal'led in bosses 36 extending rearwardly from the arch 23, and a cooperating locking dog37'which isprovided at its upper end with a flat shoulder 38 to engage the shaft 35, and a preferably integral extension'39 to engage the front side of the shaft in such a manner as to prevent the dog from passing therebeneath. The lower end of the dog 37 is provided with cylindrical extensions 40 which are journall ed in suitable bearings 41 and 42 upon the head of the frame. Desirablythe bearing 41 is open at its top to permit the insertion ofthe cylindrical extension40- in the other bearing 42. One of the extensions 40 projects beyond the bearing 42 and has coiled upon and secured to it a spring 43, the end 44 of which extends across and engages the dog 37 and acts to hold the dog at all times in engagement with the shaft Uponupward movement of the load supporting means the shaft 35 is carried upwardly until it passes the shoulder 38 upon the dog when the end 44 of the spring 43 will. force the upper endof the dog rearwardly so that the shoulder 38 will engage beneath the shaft, thereby locking the load supporting means 7 in elevated position.

The locking dog37 is so pivoted upon the main frame that the arc of its movement shown by the dotted line a in llig. 3 intersects the" arc of movement of the shoulder of the dog shown by the dotted line Z) at substantiallythe line of engagement between the shoulderh38 and the shaft so that rearward downward movement of the load supporting means is prevented while the locking is thus positioned. I

While the engagement between the shoulder 38 of the locking dog 37 andthe shaft provides a positive lock it can be easily released by rotation of the shaft 35. The shaft 35 is provided .with a pedal 45 which desirably extends upwardly in convenient reach of the operator andmay be pushed backwardly'by his foot. The rotation imparted to the shaft by such movement of the pedal 45 is in a direction to cause the rolling engagement between the shaft 35 and the shoulder 30 readily to move theupper end of the locking dog forwardly until the shoulder 38 is released from the shaft, thus permitting descent of the load supporting means. The spring 46, which, as illustrated herein, is secured at its upper end to a pin 47 extending from the shaft 35 and at its lower end to a pin 48 on the frame member 2, serves to restore the pedal to normal position in which it rests against the arch 23 of the lifting head.

Rapid descent of the load supporting means is prevented by the dash pot which is inter posed between the lifting head and frame.

The construction of the truck above described is of a very simple but rigid character. Such trucks can be constructed to carry very heavy loads and can be easily operated both to raise the load supporting means when loaded and to release the locking means when the load is supported in elevated position.

It will be understood that the particular embodiment of the invention described 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 for raising said load supporting means including parallel links acting to cause longitudinal movement of said load supporting means relatively to said frame during the raising and lowering movements thereof, a shaft rotatably mounted upon said load supporting means, a dog pivotally mounted on said frame having a shouldered free end positioned to engage said shaft when the load supporting means is raised to a predetermined height and thereby to lock said load supporting means against descent, and means for rotating said shaft in a direction to cause the rolling engagement with said shoulder to release the dog there from.

2. An elevating truck comprising a frame, load supporting means, means for raising said load supporting means including parallel links acting to cause longitudinal movement of said lead supporting means relatively to said frame during the raising and lowering movements thereof, a shaftmounted on the front end of said load supporting means, a dog pivotally mounted on said frame having a shoulder to engage said shaft and so positioned that the arc of movement of the shoulder thereof will intersect the arc of movement of said shaft caused by said parallel links at substantially the line of engage ment ofsaid shaft and shoulder, and means for rotating said shaft in a direction to cause the rolling engagement with said shoulder .to release the dog therefrom.

' '3. Anelevating truck comprising a frame, load supporting means, means for raising said load supporting means including parallel links acting to cause longitudinal movement of saidload supporting means relatively to said frame during the raising and lowering movements thereof, a shaft'mounted on the front end of said load supporting means having at its end a pedal, a dog pivotally mounted on said frame having at its upper end a shoulder to engage said shaft, andan extension therefrom to prevent movement of said "shoulder beyond said shaft, means pivotally connecting the lower end of said dog to said frame so positioned that the arc of movement of said shoulderwill intersect the arc of movement of said shaft caused by said parallel links at substantially the line of engagement of said shoulder and shaft, means acting to hold said dog in engagement with said'shaft, a pedal on said shaft operable to rotate said shaft in a direction to 'cause'the' rolling engagement with said shoulder to release the dog" therefrom, and 'resilient means acting to 'rotate'said shaft in the op-' posite direction upon release of said pedal.

4. 'An elevating truck comprising a frame, steering mechanism having 'a'tongue mounted to swing vertically, load supportingmeans having an, integral lifting head "overlying said steering mechanism, parallel links connecting said load supporting means to said frame, a lifting lever operable by a vertical:

swinging movement of saidtongueto'apply vertically a lifting force to said lifting head inapproximately the direction of the axis of said steering post, a shaft rotatably mounted on said lifting head, a dog pivotally mounted on said frame having a shoulder to engage said shaft and so positioned that the'arc of movement of said shoulder will intersect the arc :of movement of said shaft causedby.

said parallel links at substantially the line of engagement of said shaft andsaid shoulder, means for releasing the lifting means from operative relation to the tongue, and means for rotating said shaft in a direction to cause the rolling engagement with the.

shoulder to'release the dog therefrom. W 5. An elevating truck comprising steering mechanism having a tongue-mounted to nected respectively to said frame and said" lifting head, and means for releasing said locking mechanism. V

- 6. An elevatingtruck comprising a frame, steering -mechanism having a tongue mounted to swing vertically, load supporting means having a lifting head integral therewith overlying said steering mechanism, parallel'links connecting said load supporting means to said frame, a lifting lever pivotally mounted upon said steering mechanism forming an extension of said tongue and having means to engageand apply verticallya lifting force to said lifting head in approximatelythevdirection of the axis of said steering mechanism, means releasably connectingsaid lifting lever to said tongue whereby said lifting lever may be actuated by a vertical swinging movement of the tongue to lift the load supporting means, or

released to permit free steering movement of the tongue, a shaft moiinted in said lifting head, a "dog pivotally mounted upon said frame havinga shouldered upper end to .en-

gage saidshaft and lock the load supporting means in elevated position,and a pedal connected to said" shaft operable to rotate theshaft in a direction to cause the rolling engagement with said shoulder to release said dog.

'7. An elevating truck comprising a frame,

'- steering mechanism havinga tongue mounted to swing vertically, load supporting means having a lifting head integral therewithoverlying said steering mechanism, parallel links connecting said load supporting means to said frame, a lifting lever pivotally mounted upon said steering mechanism forming an extension of said tongue and having means toengage and apply vertically a lifting force to said lifting head in approximately the direction of the axis of said steering mechanism, means releasably connecting said lifting lever to said tongue whereby said lifting lever may be actuated by a vertical swinging movement of the tongue tolift the load supporting means, or

released to permit free steering movement of the'tongue,a shaft mounted in said lifting head, a dog pivotally mounted upon said frame having a shouldered upper end to engage saidshaftandlock the load supporting means in elevated position, a pedal connected to said shaft operable to rotate the shaft in a direction to cause the rolling engagement with said shoulder to release said dog, and a dash pot having a cylinder and piston connected respectively to said frame and said lifting head and located within said lifting head and protected thereby operable to cushion the descent of the load upon release of said locking dog.

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

DANIEL E. HENNESSY.

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