US2299971A

US2299971A - Lift truck

Info

Publication number: US2299971A
Application number: US393088A
Authority: US
Inventors: William S Foshee
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-05-12
Filing date: 1941-05-12
Publication date: 1942-10-27
Anticipated expiration: 1959-10-27

Description

oct. 27, 1942.

w. s. EosHr-:E LIFT TRUCK 2 Sheets-Sheet 1 Filed May 12, 1941 f am u M WM Y M. N mo m S5 Nr T l A MN 5,MWMHU NFL M m .L M QN W,

Oct. 27, 1942. w. s. FosHl-:E

LIFT YTRUCK Filed May l2, 1941 2 Sheets-Sheet 2 :INVENTOR ll//LL/M 5. V7C 05H1- f of/ F ATTOREY Patented Oct. 27, 1942 UNITED4 STATES PATENT OFFICE LIFT TRUCK William S. Foshee, Montgomery, Ala..

Application May 12, 1941, Serial No. 393,088

2 Claims.

This invention relates to a lift truck or dolly of that type adapted to straddle a load, pick it up, transport it from place to place, and set it down with a minimum of time and labor, and has for an object the provision of such a vehicle which shall be simple but extremely sturdy of construction whereby it is adapted to handle relatively heavy loads, together with improved power means for raising and lowering the load to be hauled.

A further object of this invention is to provide a vehicle of the character described which' shall be constructed principally of standard steel shapes welded together, whereby it is easy of assembly, relatively light in Weight, and capable of handling relatively heavy loads.

It is characteristic of lift trucks and dollies that they must straddle the load, and accordingly the frames thereof are necessarily open at one end and can not be cross braced except at the top and the front end thereof. The supporting wheels being on the outside of the frame, create a torsional strain on the frame, tending to spread it at the bottom. One of the distinctive features of my invention is found in the mounting of the axles of the vehicle in such a manner that they are inset with respect to the side frame members whereby to minimize this torsional spreading strain.

Another distinctive feature of my invention is found in th'e provision of a hydraulic cylinder with linkages connected thereto whereby the lifting means for the truck are all operated from a single power source.

Apparatus embodying features of my invention is illustrated in the accompanying drawings forming a. part of this application, in which Fig. 1 is a plan view of a lift truck constructed in accordance with my invention;

Fig.` 2 is a side elevation of the same;

Fig. 3 is a perspective View illustrating the method of mounting the axles for the wheels of the truck;

Fig. 4 is a detail sectional view on an enlarged scale taken on the line IV-IV of Fig. 2;

Fig. V5 is a fragmental sectional view on an enlarged scale showing the linkages for raising th'e truck and looking in the direction of the arrows V--V in Fig. 2;

Fig. 6 is a view similar to Fig. 5, illustrating the construction of one of the vertical frame members with which the lifting means is associated;

Fig. 7 is a sectional view'onan enlarged scale taken along the line VII- VII of Fig. 2; and

Fig. 8 is a piping diagram of the hydraulic' system employed in raising and lowering the lifting members.

Referring to the drawings, my improved lift truck is comprised of spaced vertically extending frame members I il, II and I2, the members I0 being at the rear of the vehicle, the members I2 toward the iront of the load carrying portion of th'e vehicle, and the members I I being intermediate the members I0 and I2 and carrying axles I4 upon which the wheels I6 are mounted.

As may be seen in Fig. 1, each of the vertical frame members is composed of two channels Il and I8, joined together across the top by channels I9 and 2 I, which latter are preferably Welded to the channels I l and I8 whereby to form as sturdy a structure as possible.

The vertical frame members IEI and I I are joined by a channel member 22, and the members7 I I and I2 are joined by a channel member 23, th'e members 22 and 23 being welded to the individual channels Il and I8, as shown in Fig. 3. A bottom brace channel 24 for the frame thus described extends from the member IIl to the member I2, being welded to both. The channel 24 lies beneath the members Il and I 8 which form the vertical frame member II, as shown in Fig. 3. The vertical frame members I0 and I2 are further strengthened by means of relatively

short plates

26, 21 and 28 welded to the outer faces of the channels I'I and I8.` The vertical frame member II is strengthened by a continuous plate 29 welded to the outer flanges of the channels I'I and I8` Secured to the inner flanges of the channels I'I and I8, preferably by welding, on both sides of the vehicle is a side wall 3I, which is joined at the forward end of the vehicle toA an end wall 32. Th'e walls 3| and 32 may be joined together by means of

angles

33 and 34 welded intov the corners, as shown in Fig. 1. The side walls 3 I being so joined to the Vertical frame members, provide additional strength for the structure. The upper ends of the vertical frame members IB, II and I2 are joined by a continuous angle 36 welded to the inner faces of the channels I'I and I8.

Fitting within the side walls 3| is a movable inner wall 3'I formed from a steel plate and having its lower edge resting on and secured to a relatively narrow plate 38. The plate 38 in turn is secured to and rests on lifting brackets 39 having upwardly extending arms 4`I to which forceis applied to raise and lower the load to be carried by the Vehicle in a manner to be described later. The side walls 3I and 3l are flared at ytheir rear ends, as shown at 42 and 43, to aid in and I8.

guiding the vehi-cle astride a load to be lifted. Also the lower plate S3 is bent downwardly at the rear, as shown at i9 in Fig. 2, for the same purpose.

Referring now to Figs. 3 and 4, I show in detail the manner of supporting the axles I4. As will be seen particularly in Fig. 3, the channels II and I3 embodied in the Vertical frame member II are cut off short of the bottom of the side wall of the vehicle, and two angles and lil are rigidly secured thereto by welding. 'Ihe angles 46 and lil are also joined to the side wall 3| and to the lower channel 24. The butt of the axle I4 is then set in between the angles 45 and M and welded into

plates

48 and 49, which latter are welded to the butt of the axle and to the

angles

46 and 41, as shown in Fig. 4. By this means the supporting axles I4 are inset with respect to the frame members, and the torsional strain on the vehicle frame tending to spread it, is greatly reduced.

At the extrem-e upper ends of the vertical frame members II and I2, on one side, I secure a channel 5I upon which is mounted a hydraulic .cylinder 52. The piston rod 53 associated with the cylinder extends rearwardly, as shown in Fig. 2, and is guided by a guide block 54 secured to the upper end of the vertical frame member Il. A crosshead 55 carried by the piston 53 has connected thereto links 5? and 58 which are vconnected at their other ends to the upper arm 59 of a bell crank which is rigidly secured to a shaft 6I mounted in a bearing 62, which bearing is supported on the angle 35, as shown in Fig. 6. The shaft `SI extends across the frame, as shown in Fig. 1, the other end being supported in a bearing 63 on the opposite side of the vehicle frame. A crank arm 64, similar to the lower arm 59 on the opposite side, is keyed to the shaft ii I.

The arrangement of lifting means is identical on the two sides of the Vehicle, and the description of one will be sufficient. The lower arm 66 of the bell crank extends through an opening 6l formed in the vertical channel member I'I, and is joined to downwardly extending links 68 housed in the space between the channels I 'I At the lower part of the frame. a bell crank having an upper arm 59 and a lower arm II is pivotally mounted on a pin 72, which is supported by a block 'I3 `welded to a relatively short channel 'I9 `which extends from the lower channel 24 to the upper channel 23 and is Welded to both of said `channels and to the side wall 3l of the Vehicle. extending plate 'I5 form an outer bearing for the pin l2, and the brace has one end secured at 'I'I to the Vertical channel member I8. 'I'he lower arm II of the bell crank just described extends through an opening 'I8 in the channel member I8, as shown in lFig. 7, and is connected to the Vertical links ES, already described. Also connected to the lower bell crank arm 'II is a short link I9 which is pivotally connected by means of a pin 8l to a guide block 82 slidably fitting between vertically extending guide members 85, which latter are welded to the channel members I'I and I8, as shown in Fig. 7. The guide block 82 is secured to the vertical arm 4I of the bracket 39, whereby, upon movement of the bell crank, vertical motion is imparted to the lifting brackets 39.

The lower arm 59 of the lower bell crank just described is connected by means of links 83 which A brace 'I5 and a vertically 1 Cil extend rearwardly through suitable openings 84 75 f the vehicle.

in the :channel members I'I and I8, as shown in Fig. 6, being joined at the rear of the vehicle to the upper arm 85 of a similar bell crank which has a lower arm 81 connected to short links 79a to a guide block 82a which is connected to the vertical arm M of the rear lifting bracket 39. The bell crank just described is mounted similarly to the forward bell lcrank on a bearing pin 88, in channel and plate members similar to 'MI and l5, supported between the

channels

22 and 24, and by means `of a brace 9| similar to the brace '18.

From the foregoing description of the lifting means it will be seen that when the piston rod 53 of the hydraulic cylinder 52 moves rearwardly out of the cylinder 52, the lifting brackets 39 are raised, thus lifting any load resting on the lifting brackets 39. When the piston rod 53 moves inwardly of the cylinder 52, the lifting brackets 39 are lowered, thus depositing any load which may be :carried by the vehicle.

It will be understood that my improved lift truck is intended to be hauled by a power means, not shown, connected to a draw bar 92 at the forward end of the vehicle. It is also contemplated that power may 'be supplied from the vehicle through a flexible shaft 93. It is from this power takeoff shaft 93 that I -contemplate developing Ithe pressure necessary to supply the hydraulic cylinder 52. The piping arrangement is best understood 'by reference to the diagrammatic Figure 8. The shaft 93 is :connected to a rotary pump 9d which draws a suitable fluid from a storage reservoir 95 mounted on the front of The fluid under pressure from the pump 9G is delivered through a conduit 91 to a three-way valve 9B. From the Valve 98, the fluid `may be discharged through a conduit 99 to the cylinder 52, or released therefrom to flow back through the valve to the reservoir 95. A pressure relief valve IGI prevents damage to the apparatus due lto building up too high pressure. A drain conduit IGZ permits any fluid leaking past the piston of the cylinder 52 to drain to the reservoir 95.

From the foregoing the operation of my improved lift truck will be readily understood. The truck is backed asti-ide a load to be carried with the lifting brackets 59 in position to engage the load. With the pump .fi-i in operation, the valve 98 is turned to connect the delivery conduit 91 with the conduit 99 leading to the cylinder 52, whereupon the piston rod 53 moves outwardly, rocking the bell crank

arms

59 and 56, and thence through the links "I9, and the bell cranks 69 and 96, exerting a lifting movement on the lifting brackets 39 and raising the load. The load may be held in its elevated position simply by moving the Valve 93 to the position shown in Fig. 8, with all the ports blanked off. For long distance hauling, it may be desirable to interpose some mechanical means, not shown, to sustain the load, many such means being known in the art. Whenever it is desired to lower the load, the valve 98 is turned to connectthe conduit 99 with the reservoir 95, thus releasing the pressure in the cylinder 525..

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a lift truck of the character described, a frame comprising a plurality of pairs of vertically disposed channels spaced to form front, intermediate and rear side frame members, transverse beams interposed between and secured to the upper ends of each pair of vertical channels, upper, intermediate and lower longitudinally extending beams interposed between and secured to the side frame members, an axle for a supporting wheel secured to the lower end of each of the intermediate side frame members, a side wall and a forward end wall for the truck body secured to the side frame members, Vertically movable lift members extending below the side Wall, and guide means for the lift members between the channels forming the pairs of Vertical side frame members.

2. In a lift truck of the character described, spaced front, intermediate and rear vertical frame members each comprised of a pair of channels the opposed pairs being joined at the top by cross channels secured thereto, vertical plates joining the adjacent webs of the pairs of channels on the outside thereof, side walls joined to the inward sides of the vertical frame members, longitudinal braces joining the Vertical frame members intermediate their ends and near the bottom thereof, lift members comprising brackets extending inwardly beneath the side walls and adapted for vertical movement, Vertical arms for the brackets extending upwardly between the vertical channels, guides secured t0 the channels for the Vertical arms, a source of hydraulic pressure, a cylinder and piston therein, linkage means connecting the piston to the lift members to raise and lower the latter, and a valve for controlling the flow of hydraulic pressure to and from the cylinder.

` WILLIAM S. FOSHEE.