US2050000A - Lift truck - Google Patents

Description

Aug. 4, 1936-. E s, FROST 2,050,000

' l' LIFT TRUCK v Filed June 4, 1954 2 sheets-sheet 2 Patented Aug. 4, 1936 i'rED WT TUEX Elmer S. Fr d, Galli.

Application re e, rase,

sa o

This invention relates to a truck designed prioperated easily for the purpose of lifting a loadand for lowering the same.

A still further-object is to provide a device or this character which permits the supported object to be rotated to any desired position while supported, there being a lock' for preventing this rotation when desired.

With the foregoing and other objects in View which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts .hereinafter more fully described and pointed out in 'the claims, it being understood that changes `may be made in the construction and-arrange-- ment of parts without departing from the spirit of the invention as claimed.

` In the accompanying drawings the preferred form of the invention has been shown.y

In said drawings 2;, Figure vl is a side elevation of the complete truck.

' Figure 2 is a plan view thereof, a portion of the top being broken away.

Figure 3 is an enlarged section through the jack. g

Referring to the figures by characters of reference i designates a suitable base mounted on casters 2 or other supports whereby it can be moved readily from place to place.

l Secured on the base, is the base block 3 of the back portion ofthe truck. |This block has a large boss i extending upwardly therefrom into a tubular standard 5 to which it-can be secured by means of screw threads as shown at t.

A yscrew threaded recess l is formed in the boss i at the center thereof and secured therein is the lower end of a cylinder t. `'l'hus an annular compartment 9 is formed around the cyl y inder t and within standard E and constitutes a eine. 729,012

to hold the standard 5 flxedly in upstanding position relative to block 3 and base i.

Formed within the block 3 at a point outside of the standard b is a threaded recess id in which is secured the 'lower end' of the cylindrical 5 casing il of a plunger ib forming a force-pump. This plunger is mounted for reciprocation within its casing and is adapted to be actuated l 'I by a handlever i9 one end of which is pivotally mounted on a supporting bracket t@ while lo intermediate portion is pivotally connected, as at 2i', to the' plunger i8. i

Extending downwardly within block Si from the recess i'is'a passage 2i intersected by an upper return passage 22 and a lower out-how l5 passage 23. .The out-flow passage 23 opens into the recess 'i as shown at 2d while the return passage 22 opens upwardly into the reservoir d as shown at 25.

Passage 22 has a valve seat i6. A check valve 2a preferably comprising a ball 2l engaged by a spring 2h is yheld normally against seat 2d so as to prevent the ilow o fluid from casingi'i and passage 2i into reservoir Si.

Passage 2i is provided with a valve seat 29 25 normally engaged by a check. valve which, in the structure shown, comprises a ball 3d held to its seat by a spring' 3i. Thus this valve will act to open under the pressure of fluid being forced into passage 2i from casing ill but t0 30 close under backward pressure from recess l and cylinder il.

A bypass connects the passages 22 and 23' and is normally,closed by a valve dit. This valve has a long stern ad extending outwardly from 35 the block. 3 andprovided with a handle, foot lever or the like shown at 35 whereby the valve can be turned readily to open or close the bypass.

A rotatable shank il@ is mounted to slide. within the cylinder d and has its lower portion i0 enlarged as at di to form a piston. To the upper end oi this shank is securely fastened the top @e of the jack and to this top is pivotally connected a spring-pressed dog'. te adapted to be seated in any .one of the notches i3 so as to hold the 45 shanlr 3d and top t3 against rotation. This dog is of sumcient length to remain in engagement with a notch while the shank @e is being moved upwardly vor downwardly as hereinafter -explained. A It is to im understood that reservoir 9 is to be partly filled with a suitable fluid such as oil and, in order to prevent the creation of` a vacuum within the reservoir, vent tubes t0 can be.sup' ported within the upper portion ot the reservoir,

eachot these tubes having openings I for permitting the ilow or air into or out of the reservoir. f

If it is desired to lift a. stove or other heavy object, the truck is moved to position thereunder with the top 38 in its lowermost position. The lever I9 is then actuated to reciprocate vplunger I8. During each upward stroke of the plunger ou win be sucked into the casing l1 by way of passage 22 at which time valve 2 1 will open and valve 3U will remain closed. During each downward stroke of the plunger, valve 21 will close and valve 30 will open. Thus the oil forced out of the casing I1 by the descending plunger will ow into passage 2! and thence to passage' 23 from which it will enter cylinder l beneath piston 31 and cause the shank 36 and the load thereon to move upwardly. As valve 30 will prevent return ilow of the liquid, theel'evated parts will be held against movement downwardly when the pumping action is discontinued. The

truck with the load thereon can then be moved to any point desired, it being understood that the dog 39 will prevent the load from turning.

Thereafter the dog can be disengaged from the* notched head and the to'p 31 rotated to bring the stoveor other object into proper position to be lowered. By now opening valve 33 the liquid under the piston 31 will be free to flow through bypass 32 into passage 22 and thence back. to the reservoir where it will be stored for further use. As the iluid thus escapes to the reservoir the load'will be gently lowered into position and thereafter the truck can be withdrawn. 4

What is claimed is:

1. In a lift truck, a Wheel supported base, an upstanding cylinder thereon, a piston slidable and rotatable in the cylinder and having a shank extending upwardly from said cylinder, a load engaging element at the top of the shank and rotatable with the shank and piston, means for elevating the piston and shank relative to the cylinder, an annular head on the cylinder, a member pivotally suspended from the load en- 5 gaging element, said member being adapted to slidably engage the head during the sliding movement of the shank, said head having means for cooperating with said member for holding the shank and load engaging element against rotation relative to the cylinder after therotation of said shank and element to certain predetermined positions. v

2. A lift truck including a wheel supported base, a cylinder mounted thereon including' a 15 cylinder and a shank slidably and rotatably mounted within and above the cylinder, an annular head on the cylinder, a, load engaging .element movable with the shank, and spring pressed means extending from the said element for slid- 20 ably engaging said head and for holding said element and shank against rotation after their rotation to any one of a series of predetermined positions.

3. A truck including a base, an upstanding 25 cylinder thereon, a slidable and rotatable shank guided and surrounded by the cylinder, a loadengaging element at the top of the shank adjustable angularly with the shank to any one of a plurality of predetermined positions, and cooperating means on said element and the cylinder for holding said element against rotation after annular adjustment to a selected position without interfering with its reciprocation, said means including a head xed to the cylinder 35 and having a series of notches in its periphery, and an elongated dog depending from the loadengagingwelement and slidable within one of the notches during the reciprocation of the shank.

I ELMER S. FROST. 40

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