US 2509911 A
Description (OCR text may contain errors)
May 30, 1950 R. DORE HOIST FOR DUMP TRUCK BODIES 2 Sheets-Sheet 1.
Filed Dec. 18, 1948 fito/w@ z S May 3U, 1950 R. DORE HOIST FOR DUMP TRUCK BODIES Filed Dec. 1s, 1948 2 Sheets-Sheet 2 fave/fof Patented May 30, 1950 UNITED STATES rrrslvr OFFICE Application December 18, 1948, 4Serial No. 66,646 In Canada. November 10, 1947 4 Claims.
The present invention relates Ato a hoist and, more specically, to a hydraulically-operated hoist for dump-truck bodies.
A characteristic oi 'such hoists is'that the body or box of the truck is pivotally raisedby cylinderand-pi'ston means connected between the body and the chassis. When the box is in loweredposition resting on the chassis, the cylinder and piston are disposed underneath the former With their aies substantially parallel to the bottom thereof. With the hydraulically-operated members thus ineffectively disposed, a tremendous starting thrust is required in the system in order to displace the box upward. Such mechanisms may even eofhe jammed undef unusually heavy loads.
The `problem set forth above has long been recognized, but it has been found diicult to arrange a hoist electively in the limited space available beneath a truck body. In consequence, most attempts to improve truck-dumping mechanisms have been centered upon the connection between hoist and body. Thus it has been found that an improved mechanism is obtained when the body and chassis are connected by two or more pivoted links, and the latter actuated by piston means with, or without, the aid of a crank. Unfortunately this elaborates and increases the cost of the machinery, and such systems still require `excessively high vstarting pressure in the hydraulic system.
The present invention seeks to solve the problem in a much simpler and more effective Inanner than that suggested above. Thus it is the` principle ofthe invention that, at the moment of raising the body from a restingposition, a pistonactuated crank brings into play a lever which directly lifts thebcdy upward. When the latter has been somewhat, the cylinder-andpiston means, whose axis is now disposed at an eiective angle relative to the bottom of the body, arry the dumping 'operation to completion.
The main object, then, of the present invention is to provide a hoist for dump-trucks which does not require excessively high starting thrust in order to raise the body from the chassis.`
li/loreover, another important object resides in the provisin o'f a hoist off the character described which is simple in cnstructin and economical to ahftili.
And anmer object is to' provide a hoist as set forth above is light, y'et durable in operation.
Other objects and advantages will become apparent or be further pointed out in the description to follow.
As an example. and for purposes of illustration 2 only,`a preferred embodiment of invention is shown in the annexed drawings, wherein:
Figure l shows a perspective view of the body l and part ofthe chassis of a dump truck, the former maintained in raised position by the hoist of thisinvention; 1 c Fig. 2 shows a detail perspective view of the lever and crank mechanism of the hoist;
Fig. 3 shows a plan view of the hoist; Y Fig. 4 showsv an elevation along the'line Il-li in Fig. 3 with the body in lowered position, and Fig. 5 rshows a corresponding elevation View with thecbody in partially-raisedposition. c
Referring n'ow to the drawings, wherein the same reference characters denote corresponding parts throughout, the hoist of the invention seen to be associated with the body B and chassis CV of a truck, and consists mainly of the cylinder ZIJ, piston 2l, and the crank-and-levei members 22.` c The essential parts of a typical body and truck chassis are indicated in the drawingsrin order to aid in understanding the operation of the in'- vention. Thus Fig. 1 shows that the box of the body is supported and strengthened by the longi tudinal stringers 6 which `are in turn supplemented to the channels 1c. Secured to these channels near the rear of the body are the pivotblocks 8 which are pivoted in any suitable sockets disposed on the chassis supports. The chassis is provided with a pair of channels 9 upon which channels l are adapted to rest when the body lowered into normal position. The channels 9, in turn, are secured to and bedded on the sleepers or stringers I0 of thechassis, and will havethe usual transverse, reinforcing angle-bars such as Il welded across the stringers. For the purpose of this invention, two longitudinal supporting bars such as I2 will be disposed between anglebars il inside channels 9, and will have welded thereto the supporting frames I3 near the ff ward ends thereof. The frames I3 will act` as' bearingsY in which the crank-and-lever mechan ism will be pivotally mounted, as hereinafter described. I c Piston 21| is Slidable in cylinder 20, and iS actuated by the hydraulic pressure in the latter. A system for controlling the displacementof the piston is shown in Figs. 4 and5 where apump V'i3 is powered by the transmission of the truck through shaft 24, and feeds oil through lines 25 and 2e into Ieither end of the cylinderr lThe pump may be controlled by any suitable means through the line 21. The free end of the piston is pivotally secured to the base of the body :as at 28, substantially near the middle of the latter.
At the opposite end to the piston, cylinder 2| is pivotally connected to the crank-and-lever mechanism of the hoist. Since this mechanism is in turn pivoted to supports on the chassis, any displacement of the piston causes a corresponding displacement of the body together with, or independent of, the lever mechanism.
Figs` 2 `and 3 best show the dispositions of cylinder, crank and lever relative to the chassis supports. Thus the chassis frames I3 are provided, near the forward ends thereof, with integral, lateral 'collars or sleeves i4. These collars act as bearings for a shaft 29 which extends transverse the chassis above and between channels 9.
Inside each frame I3, a short crank-arm 30 is keyed to shaft 29. The free ends of each of these crank arms are connected by a pin 3l and the ad jacent end of cylinder 20 is rotatably mounted on this pin. Hence any axial displacement of the cylinder will actuate the crank mechanism and cause rotation of shaft 29.
.Keyed to each end of the shaft 29 outside frames I3 are the lever arms 32. These arms are substantially longer than the crank arms and are adapted to raise the body of the truck when shaft 29 is angularly displaced. Projecting inwardly from each reinforcing channel of the body will be disposed a roller 33 adapted to rest on lever arm 32. This arrangement will reduce friction during upward displacement of the body.
The operation of the hoist is as follows:
When the body of the truck is at rest on the chassis, the piston will be disposed mostly inside the cylinder; both these members being secured between theV crank mechanism and the body with their axes very nearly parallel to the bottom of the latter in the limited space therebeneath. The crank mechanims arms, however, are disposed at an effective angle to the cylinder axis, and so, upon introduction of pressure into the system, the cylinder is driven against the crank and causes shaft 29 to pivot. The lever arms 52 are hence pivoted upward, as between Figs. 4 and 5, and carry withthem the body of the truck.
When the crank has been displaced to some extent by the cylinder, the latter comes into contact with shaft 29 andcauses a binding of the crank and lever system. However, at this point the lever arms have reached their highest point, and have raised the body to an langle where the piston and cylinder are eiectively disposed to complete the dumping operation.
Obviously, from the foregoing, the present invention fullls the objectives hereinbefore set forth. Whilst avoiding the introduction of expensive and weighty systems of connected links between body and chassis, nonetheless this invention solves the problem of effectively disposing a simple hoist in the limited space below the body of a truck. The hoist described reduces greatly the hydraulic pressure required to start the dumping operation, yet is of such la nature as to Y herein shown and described, but that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.
Having thus described my invention, I claim:
1. The lcombination with a dump truck having a chassis, a body pivotally mounted thereon and hydraulically-operated cylinder-and-piston means connected at one end to said body and adapted to raise the latter from the chassis, of means for aiding in the initiation of upward displacement of the body comprising a shaft rotatably journalled transverse the chassis, lever arms keyed to said shaft adapted to engage the bottom of the body during the rst portion of the upward displacement thereof, and a crank keyed to said shaft and pivotally secured to the free end of said cylinder-and-piston means.
2. A hoist for dump trucks having a body and chassis, said hoist adapted to raise said body from said chassis and comprising: lever means pivotally mounted on said chassis engageable with the bottom of said body, and hydraulically-operated cylinder-and-piston means connected between said lever means and said body, whereby elongation of said cylinder-and-piston means causes, firstly, a pivoting of said lever means to displace said body upwardly somewhat, and secondly, a direct upward displacement of said body.
3. In a dump truck having a body and a chassis, a hoist adapted to raise the former from the latter and comprising: a crank and a lever movable together and pivotally mounted on said `chassis, said lever engageable with the bottom of said body, and hydraulically-operated cylinder--andpiston means connected between said crank and said body whereby elongation of said means causes rstly a pivoting of said crank and lever to raise the body Somewhat and secondly causes direct upward displacement of said body.
4. In combination with a dump-truck having a body and chassis, a hoist adapted to raise the former from the latter and comprising: a transverse shaft rotatably journalled in said chassis, lever arms keyed to said shaft engagable from the bottom of said body, a crank keyed to said shaft, a cylinder and a piston co-operable therewith connected between said crank and said body, and hydraulic means for displacing said piston in said cylinder; wherebyl displacement of said piston out of Said cylinder causes, rstly, a pivoting of said crank shaft, and lever to move said body upwardly a predetermined amount, and secondly, direct upward displacement of said body.
REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,355,763 Lally s- Oct. 12, 1920 1,757,190 Higgins May 6, 1930 1,793,851 Hartman Feb. 24, 1931 2,172,138 Harley Sept. 5, 1939 2,319,840 Barrettv May 25, 1943 2,452,516 Brick Oct. 26, 1948