US2895623A - Crane construction - Google Patents

Description

July 21, 1959 n EQ A. uRBANowlc-z CRANE CONSTRUCTION Filed Dec. 2. 1953 f2!- IN VEN TOR.

ammo A. UaANon// u m 4 E 3 C M? 5.44 4,2 W W7 v60 M/ N A United States Patent O CRANE CONSTRUCTION Edward A. Urbanowicz, Cleveland, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Chio Application December 2, 1953, Serial No. 395,735 3 Claims. (Cl. 212-59) Cranes commonly have booms for load-carrying arms which are of great length in proportion to the entire installation. In case of motor cranes or locomotive cranes such as are required in plant usages, the presence of overhead beams or piping, etc., in many instances necessitates the lowering of the boom in passing under such obstacles. Where the loads carried are relatively light, no great diiculty is encountered in this, but in other instances where it is desired to transport loads of considerable weight in plant locations having overhead obstructions, the maneuvering of the crane thereunder constitutes a considerable problem, which is generally handled by dropping the load near the overhead obstruction and lowering the boom and running the crane through and then by maneuvering into the proper position raising the boom and pulling the load into place where it can be raised. Also, in the usage of a long boom crane with heavy loads, the boom is raised into nearly vertical position before the load is picked up, as the mechanical leverage is too unfavorable for correspondingly raising the load from the horizontal boomposition to the desired carrying elevation. By the present invention however, it now becomes possible for a long boom crane to carry its load and dip as necessary to dodge under piping or other overhead obstructions, in moving about in a plant or in building-operations. As readily seen, this results in great savings of time and labor. Other objects and advantages of the invention will appear from the following description.

To the accomplishment of the foregoing and related ends, said invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. l is a side elevational view of a crane embodying the invention;

Fig. 2 is a schematic showing of the triangular factors involved;

Fig. 3 is an enlarged scale front elevational View of guide means between the pivoted end of the boom and the sheave system over it;

Fig. 4 is a side elevational view of fluid-pressure means for varying the distance between the boom end and the sheave system above it;

Fig. 5 is a similar view of a motor driven screw for accomplishing the same purpose;

Fig. 5a is an enlarged transverse section on line 5a of Fig. 5;

Fig. 6 is a vertical section on line 6 6, Fig. 3; and

Fig. 6a is an enlarged transverse section on line 6a of Fig. 6.

In general, the invention centers about means for changing the distance between the pivoted boom end and the sheave system above, such that this distance can be 2,895,623 Patented July 21, 1959 rice adjusted at will in operation, to accommodate to various conditions of load movement, and particularly where it is desired to lower and raise the boom in dodging overhead obstructions, and without ne;essity of stage-wise un-loading.

Referring to the drawing, a crane equipped with a boom 2 pivotally mounted at 3 on a winch-platform is arranged with an overhead sheave system comprising duplicate sheaves 4 wtih their take-up cable 5 to the winch 5a, extending further over paired sheaves 6, whereby the paired cables from the winch may shorten or lengthen the distance between the sheaves 4 and 6 and thereby raise and lower the free end of the boom, connection from the sheave 6 to the end of the boom being by a cable or rod 7 as in well known practice. And a load-hoisting cable 8 trained over another sheave 21 in the mounting along with sheaves 4 is trained over a sheave 10 at the boom-end, and carries the usual hook 11. The detail of the operators cab and the winch platform mounting may vary widely, and for illustration is shown as a tractor 12 supporting a turntable 14 which in turn carries the cab 16. Guide means G is arranged between the pivoted end 3 of the boom and the sheave support above, such guide means, as shown in further detail in Fig. 3, comprising an internally channeled member 18 pivotally connected at 19 to the end of the boom, and this guide receives in its parallel channels a slide member 20 in close working relation, the upper end of which carries the sheaves 4 for the take-up, and also the sheave 21 for the load-carrying line 8. As thus seen, the guide compensatively swingable at its lower pivoting to the end of a boom, allows the slide member 20 to compensatively slide out or in as and when up or down movement of the sheave system is imposed by means'E now described. As such in detail, a fluid pressure cylinder 22, Fig. 4, is pivoted at 23 to the boorn, and suitable hose connections 24, 25 are provided for supply and exhaust of pressure fluid to move the piston, as controlled by suitable valving. The piston rod 26 is pivotally connected at 27 to the sheave-carrying head, and it is seen from this that by admitting pressure fluid to the lower end of the cylinder, the piston rod 26 is extended and raises the sheave head as desired, for instance to the position 4a, Fig. 1; and thereby the distance between the end of the boom and the sheave-head is materially lengthened. Conversely, the piston can be lowered together with its supported sheave-head, by appropriate control of the pressure fluid. The effect of this change in the distance between the end of the boom and the sheave-head is to increase the length of the short side of the triangle which is otherwise made up by the boom and the Itake-up. Thus, as seen in Fig. 2, the triangle with the long sides 2 and 6 and the short side 3-4 constitutes a gigantic bellcrank lever fulcrumed at 3, and having bellcrank arms 4-3 and 3-10, in the ordinary positioning, and constituting bell-crank lever 4a3-10 in the extended positioning. Manifestly, the bell-crank arm 4a-3 in proportion to the arm 3-10 -is much greater than bell-crank arm 4 3, and the short arm may readily be extended from 3 to 4a. Correspondingly, a leverage advantage is gained for the boom in its lowered or near-horizontal position. And, it is found that with a load on the cable 8 the crane can be moved along under overhead obstructions, the operator merely lowering the boom at the points required and then raising it again as he travels along.

ln Fig. 5 is shown a screw mechanism which is desirable in some instances for extending the sheave-head instead of the foregoing fluid-pressure means. This comprises a guide barrel 22' with screw 26' to be turned by worm drive 29 from the servomotor 30 bracketed at the top of barrel 22' and having its shaft mounted in bearinglugs, thereby axially moving-the threaded rodv26 up and down without rotation. The lower end of the guide barrel 22 is pivoted at 23 to the end of the boom, and the screw'26 which travels 'axially without rotating, is pivoted at its' upper end'27ftothe sheave-mountingrhead;

Themanner' of' operationisclear from the foregoing:-

slide 20 ofthe guide means G, one device can perform the functions of both the guide G and the expanding means E of Fig. 1. Thus, as shown in Figs. 3, 6 and 6a, the slide 20 is provided with rack-teeth 33 on the inner edges of the slide,.it being noticed that Fig. 6 is a vertical section on the line 6-6 of Fig. 3, and at the top of the guide frame 18 a servo-motor 30' is bracketed and has its shaft 31 mounted in bearing-lugs 32', and carrying a drive-pinion in mesh with the rack-teeth 33. On the free end of shaft 31 is a sprocket 34 which by a chain connects with and drives a companion sprocket and shaft which carries a corresponding drive-pinion 29. This companion sprocket is engaged underneath by the chain which then loops up over an idler 35, thereby giving drive in the same direction to both pinions.

Other modes of applying the principle of the invention maybeemployed, change being made as regards the detailsdescribed, provided thefeatures stated in any of the following claims or the equivalent of such be employed. Y

I therefore particularly point out and distinctly claim as my invention:

l. In crane construction, the combination of a frame, a boom pivotally secured at one end to said frame, an extensible guide assembly pivotally mounted by the frame at a point closely adjacent the thus secured end of the boom and extending upwardly therefrom, boom-suspension means extending between the upper end of said guide assembly and an outer end portion of said boom, an expansion strut pivotally supported at one end on the boom and connected at its other end to an upper end portion of the guide assembly, and drive means for regulating the length of said expansion strut to vary the spacing of the guide assembly engagement with the boom-suspension means from the pivotally secured end of the boom.

2. In crane construction, the combination set forth n claim 1 characterized further in that said expansion strut is in the form of a fluid-pressure piston-cylinder assembly.

3. In a crane including a frame and a boom pivotally connected at one end to said frame, boom-suspension means connected to the other end of the boom and extending therefrom in angular relation toward the frame, said suspension means including a sheave head and a boom line about the same, a guide member having one end mounted on said frame and its other end connected to said sheave head, and means for changing the mechanical advantage of the suspension means in operation of the crane, said last-named means comprising a strut pivotally supported at one end on said boom and extending upwardly to the sheave head at its other end, said strut being adjustable to raise and lower said other end thereof and operative to support the sheave head in various elevated positions, and power means for thus adjusting the strut.

References Cited in the file of this patent UNITED STATES PATENTS 984,670 Heedwell Feb. 2l, 1911 1,163,786 Smith Dec. 14, 1915 1,817,809 Eilersgaard Aug. 4, 1931 2,348,285 Ekbom et al May 9, 1944 2,378,915 Davidson June 26, 1945 2,391,440 Anderson Dec. 25, 1945 2,609,940 Grundvig Sept. 9, 1952 2,738,884 Callouette May 20, 1956 2,774,484 White Dec. 18, 1956 FOREIGN PATENTS 663,900 Germany Aug. 16, 1938

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