US2237439A - Shovel crane boom - Google Patents

Description

, 1941., b. c. JONES 23375439 SHOVEL CRANE BOOM Filed March 2, 1940 j ATTORNEYS Patented Apr. 8, 1941 SHOVEL CRANE BOOM Daniel 0. Jones, Milwaukee, Wis., assignor to Koehring Company, Milwaukee, Wis., a corporation Application March 2, 1940, Serial No. 321,966

1 Claim.

This invention has to do with exavating machines of the type commonly known as shovel cranes or power shovels, wherein there is employed a shovel boom and dipper means mounted on the boom and operated from the power plant carried on the body of the crane.

The ordinary operation of cranes of this type contemplates an excavating movement of the dipper or shovel member usually involving elevating action thereof as it is crowded to do its work, a lateral swinging or sweeping of the dipper and its handle by which it is connected with the boom to bring it to an unloading position over a vehicle or a place on which the contents ,of the dipper may be dumped, and a subsequent restoration of the dipper by reverse operations to bring it back to its excavating position. The dipper stick either straddles the supporting boom therefor, or passes between spaced parts of such boom and the usual constructions. The stick forms a long lever, and the operations of the crane usually are such that the car or body of the crane turns to swing the boom and dipper instrumentalities. Considerable momentum of these parts is created in their movement. The ordinary operation of the machine, furthermore, for eiiiciency, requires rather sudden stopping of the boom movement for swinging, this being true both when the dipper is loaded and when it is unloaded. Necessarily, this action of the boom and dipper in the stopping movements creates severe stresses and strains both upon the boom supporting means at the point of connection with the crane body, and upon the dipper stick or handle itself. At times the operator of the machine accidentally side-swipes a vehicle or bank or other obstacle with the dipper, giving rise to additional severe torsional strains on the boom and on the connections at the foot of the boom.

In Patent No. 1,662,902 and in Patent No. 1,954,- 119, there are disclosed constructions designed to protect the supporting boom from torsional forces tending to rotate the boom about an axis longitudinal of the boom caused by the inertia of the dipper upon sudden starting and stopping of the swinging movement of the dipper and by the dipper striking substantially rigid bodies during such swinging movement. The constructions disclosed in such patents employed various arrangements of coil springs for absorbing the shocks and forces to which the supporting boom was sub-- jected and which would otherwise have had a damaging effect upon the structure of the boom and the connections of the boom to the swing body.

The present invention relates to an improved modification particularly adapted for use with a supporting boom 01' unitary welded construction adapted to house part or the mechanism employed ior imparting the crowding out and racking in movements to the dipper stick and dipper and to which type of supporting boom the application of the invention disclosed in the above mentioned patents would be difficult and complicated.

In the present invention, there is employed a substantially rigid and unitary supporting boom of Welded construction. The foot 01' the boom is provided with a pair of supporting arms and there is employed a novel form or connection for securing the boom to the crane or swing body. This construction provides tor a pivotal movement or the boom for raising and lowering the shovel and rubber pads are provided I'or insulating the boom with respect to the crane or swing body and for absorbing the shocks due to forces tending to rotate tne boom about an axis longitudinally of the boom. The rubber pads operate to resiliently resist turning movement of the boom about its longitudinal axis with respect to the swing body to which it is secured.

In the drawing, there is shown a preferred embodiment of the invention. In this showing:

Figure l is a diagrammatic side elevational view of a shovel crane constructed in accordance with the principles of this invention.

Figure 2 is a fragmentary top plan view of a part of the shovel crane illustrated in Figure 1 and showing the manner in which the supporting boom is connected to the car body.

Figure 3 is a side elevational view of a part of the connection shown in Figure 2, one of the supports by which the boom is connected to the car body being broken away to show the manner in which the pivot block is mounted in the supporting arm at the foot of the boom.

Figure 4 is a sectional view taken substantially on the line 4--4 of Figure 2; and

Figure 5 is a partial sectional view taken through the top of one of the pivot blocks illustrating the corrugations formed on one of the faces thereof.

Referring to Figure 1 of the drawing, A designates a swing car or body supported by a turntable B mounted on endless tracks C. D designates a supporting boom on which is mounted a dipper stick E carrying a shovel dipper F. The dipper F is hoisted by a hoisting cable G and suitable crowding out and racking in mechanism is provided for imparting outward and inward movements to the dipper stick E and the shovel dipper F, in a manner well known in the art.

Since the shovel dipper F in the usual shovel crane construction is of considerable weight and occupies a position spaced from the boom D, it will be apparent that the inertia of the dipper stick E and shovel dipper F upon sudden starting and stopping of the swinging movement of the car body A will subject the boom to heavy torsional strains and forces and will tend to impart a rotating movement to the supporting boom about its longitudinal axis. Continued application of such forces to the supporting boom will in the course of time have a damaging effect upon the structure of the supporting boom. This is particularly true in those cases wherein the supporting boom is formed substantially in a unitary piece of welded integral construction adapted to house the racking in and crowding out operating mechanism for the dipper stick. To prevent damage to the supporting boom from such forces, there is provided a novel connection for securing the boom to the car body which will absorb the shocks of the forces referred to.

As best shown in Figure 2, the foot of the boom D is provided with a pair of supporting arms I by which the body of the boom D is connected to and supported by the swing car body A. Each of the supporting arms I is provided with an opening 2 in which is mounted pivot blocks 3. The top and bottom faces of the pivot blocks 3 are insulated from the top and bottom sides of the openings 2 by rubber pads 4.

Bearing members 5 are provided on the sides of the opening 2 for engagement with the sides of the pivot blocks 3 for holding the pivot blocks 3 in a desired position. The bearing members '5 may either be an integral part of the sides of the openings 2 or may be shims insertable in the space between the sides of the pivot blocks 3 and the sides of the openings 2. The bearing members 5 permit turning movement of the boom D about its longitudinal axis 6 with respect to the car body A. The sides of the bearing or pivot blocks 3 are provided with oil grooves 1 connected by an opening 8 drilled through the body of the pivot blocks with an annular oil groove 9 formed on the interior surface of the opening I extending through the pivot blocks 3. The rubber pads 4 operate to resiliently resist turning movement of the boom D about its longitudinal axis in a manner to be described.

Each of the pivot blocks 2 is secured to the car body A by a pivot pin II journaled in the opening IE]. Each of the pins II is carried by a pair of supporting arms I2 rigidly and integrally secured to the car body A. The pins II are mounted in openings formed in the supporting arms I2 and turning movement of the pins I! is prevented by means of a locking bolt I3 extending through the body of the pins I I and a lug I4 formed integrally with one of the supporting arms i2. The construction permits pivotal movement of the pivot or bearing blocks 3 and the boom D about the axis of the pins I I to provide for raising and lowering of the boom with respect to the car body A.

It will be recalled that the arrangement of the pivot blocks 3 and bearing members 5 permits turning movement of the boom D about its 1ongitudinal axis 6. Upon the subjection of the boom D to forces from the dipper stick E and dipper F tending to rotate the same about its longitudinal axis 6, the rubber pads 4 will operate to resiliently resist such turning movement and absorb the forces tending to cause such turning movement and prevent damage to the boom D by reason of such forces.

Although the boom D has been described as being resiliently insulated from the bearing blocks 3 by means of the rubber pads 4, it will be understood that the bearing blocks 3 could be insulated from the body of the swing car A without departing from the principles of this invention.

The top and bottom surfaces of the pivot blocks 3 engageable with the rubber pads 4 are corrugated or grooved transversely thereof as illustrated in Figure 5 and as indicated by the dotted lines I5 in Figure 4. The transverse corrugations or grooves operate to hold the rubber pads 4 in position with respect to the top and bottom surfaces of the bearing blocks 3 upon pivotal movement of the boom D about the axis of its supporting pins II.

The arrangement of the bearings 3 and rubber pads 4 also operate to relieve the boom from shocks due to operation of the crowding out and racking in mechanism. Since the boom D carries the chain and mechanism used for this purpose, operation of such mechanism creates a force which tends to lift the foot of the boom D or supporting arms I vertically from the position shown in Figure 3. Accordingly, it will be apparent that the pads 4 cushion the boom from the shocks or forces referred to and incident to the operation of the dipper stick crowding out and racking in mechanism.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

In apparatus of the class described, a support, a rigid and unitary boom element having a pair of supporting arms at the base thereof, each of said supporting arms being provided with openings having pivot blocks mounted therein and rubber pads insulating the top and bottom sides of said pivot blocks from said supporting arms, and means connecting said boom element to said swing body for pivotal raising and lowering movement with respect thereto comprising pivot pins rigidly secured to said swing body and journaled in said pivot blocks, said rubber pads being effective to absorb torsional forces tending to rotate said boom element about a longitudinal axis located substantially at right angles to its axis of pivotal movement by permitting and resiliently resisting turning movem nt of said boom with respect to said pivot blocks and said swing body.

DANIEL C. JONES.

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