US2078393A - Portable crane - Google Patents

Description

April 27, 1937. R. G. LE TOURNEAU 2,078,393

PORTABLE CRANE Filed Oct. 15, 1955 2 Sheets-Sheet 1 I\ N N N 3' INVENTOR l 4 R. G.LeT0Lu'12eaw April 27, 1937'. R, G, LE TOURNEAU 2,078,393

PORTABLE CRANE Filed Oct. 15, 1935 2 Sheets-Sheet 2 INVENTOR RGLBTOuI'Heau Patented Apr. 27, 1937 PATENT OFFICE ron'ranm cam Robert 0. Le Tonrnean, swims, aasignor. to B. GrLe Tournean, Ino., Stockton, Calif.,,a

corporation Application October 15, 1935, Serial No. 45,040

Claims.

This invention relates to portable wheel mounted cranes adapted to be connected to and operated from a tractor, my principal object being to provide an apparatus of thistype having great lifting capacity for its size, and great flexibility of operation, and which can be used for general utility purposes by construction engineers, contractors and others, as for'instance to load and unload heavy equipment, handle large concrete or steel pipe, place heavy members in bridge construction, set machinery, move heavy equipment for repairs or other purposes, and for innumerable other duties.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views: Figure 1 is a side elevation of my improved 25 crane as attached to a tractor.

Figure 2 is a rear end view of the crane with the cables removed.

Referring now more particularly to the char acters of reference on the drawings, the crane 30 comprises a relatively long rigid tongue I adapted wheels 8 are turnable. The above parts form the supporting base or vehicle of the crane.

The boom of the crane comprises transversely 0 spaced upwardly converging arms 9 braced in a transverse plane by suitable members I0 and in a longitudinal plane by a truss structure I I. The arms at their upper end are bent rearwardly so as to provide rearwardly overhanging portions 45 I! when the boom is in a vertical position as indicated in dotted lines in Figure 1. To keep the boom from tipping forwardly from such vertical position I provide a pad l3 disposed some distanceahead of the boom to then rest on the tongue; said pad being rigidly connected to the boom at spaced points in its length by suitable laterally diverging arms l4.

Plates I! are rigidly secured to and depend 55 from the lower ends of the arms 9, these plates projecting between the bosses B and the wheels and turnably engaging and supported by the adjacent portions of the spindles 'I.

A sheave block it is rigidly fixed between the upper rear en'ds of the arms 9, and another sheave block i1 is similarly fixed in connection with the truss structure II at its upper peak ahead of the block it. A cable l8 extends from one drum of a power unit IS on the tractor (this unit being preferably as shown in my Patent No. 1,912,645, dated June 6, 1933) over and between certain pulleys of the blocks I! and I8, and over those of the hook or lifting block which is disposed below and in vertical alinement with the block IS. The winding of this cable on its drum of course raises the block l9 and any load supported thereby, and vice versa.

Another cable 2| extends from the other drum of the power unit and then over another pulley of the block I1, and then back and forth between said block and an anchor sheave block 22 flexibly mounted on the tongue adjacent its forward end. This cable is the boom controlling line and is arranged so that when the cable is wound on the corresponding drum, the boom itself will be raised about the wheel spindles as an aids.

A crane as above constructed has great lifting capacity and can handle heavy loads with safety. For example, a crane having a substantially 30-foot boom and a 20-foot tongue, from the center of the wheels to the point of connection with the drawbar, and connected to a tractor of average weight, can lift five tons when the lifting block is disposed 16 feet rearwardly of the wheel center, and from there up to twelve tons when the said lifting block is 7 feet from the wheel center.

The reason such loads can be thus lifted is on account of the fact that the load is carried on the wheels and the tractor simply acts as a counterbalance. With the main weight of the tractor substantially 25 feet away from the point at which the load is concentrated, it will readily be seen, following the principle of leverage, that when the load is swung 12 feet into space, the crane will be capable of lifting twice as much weight as the tractor (disregarding the weight of the boom), since the tractor is twice as far away from the wheels as the load is.

While when in use the crane is connected to a tractor, its wheels may be equipped with rubber tires if desired, so that it may be towed by a tractor from one place to another. The relatively great length of the tongue gives the tractor operator perfect maneuvering control, allowing him to move in a straight line back and forth or cramp around sideways so as to spot his load within a fraction of an inch. The general construction or form of the boom, with its rearward-' 1y overhanging portion at the top, and the fact that it may be positively held in a vertical position, enables the crane to be very effectively used for breaking up concrete or the like with a skull cracker; or by the addition of suitable guides the crane may be used as an efficient pile driver.

When making connection with a tractor the cables are first attached to the drums of the power unit, the boom at the time resting on the ground rearwardly of the tongue. The operator then reels in on the boom line. The boom being heavier than the tongue raises the latter of! the ground so that the drawbar may be easily engaged with the front end of the tongue and the drawbar pin inserted in place. The boom may then be further raised to any desired angle. In disconnecting the crane from the tractor it is not necessary to block the wheels; the operator simply releasing the boom line so as to cause the boom to lie flat on the ground, and then pulling the drawbar pin. This ease of connecting and disconnecting the crane from the tractor makes it unnecessary to have a tractor for use only with the crane, when the crane is being used but intermittently. An average of ten minutes is all that is necessary to attach and put the crane in operation, and a similar short period of time is all that 'is required for disconnecting purposes.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention, what I claim as 'new and useful and desire to secure by Letters Patent is:

1. In combination with a tractor, a crane comprising a relatively long tongue swivelly mounted on and supported at its front end by the tractor, wheels supporting the tongue at its rear end, and a boom pivoted in connection with the tongue .axially of the. wheels for swinging movement relative to the tongue.

2. In combination with a tractor, a crane comprising a relatively long tongue swivelly mounted on and supported at its front end by the tractor, transversely spaced wheels to the sides of the tongue at its rear end, wheel spindles mounted in connection with the tongue, and a boom comprising transversely spaced arms having elements at their lower ends turnably engaging the spindles.

3. A crane comprising a tongue adapted at its front end for supporting connection with a vehicle, wheels supporting the tongue at its rear end, and a boom supported for swinging movement about the axis of the wheels.

4. A portable crane comprising a base having a forwardly projecting tongue adapted at itsforward end for attachment to the drawbar of a tractor, wheels supporting the base at its rear end, and an upstanding swinging boom pivotally mounted on the base axially of the wheels.

5. A crane comprising a base adapted at its front end for supporting connection with a vehicle, wheels supporting the base at its rear end, a boom supported for swinging movement about the axis of the wheels, said boom extending straight up from its lower end to a point short of its upper end and being then deflected to provide a rear overhang, a load engaging element depending from the rear end of the overhang and means to raise the boom to dispose the straight portion thereof vertically; whereby the weight of a load supported by the element will then be transmittedto the base substantially at the axis of the wheels.

ROBERT G. LE TOURNEAU.

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