US1715664A - Boom-hoist safety means - Google Patents

Description

June 4, 1 9- E. H. LICHTENBERG BOOM HOIST SAFETY MEANS Filed Feb. 1, 1928 INVENTOR I Q E. H. Lichfenbe lq Patented June 4, 1929.

ERICH H. LICHTENBEBG, or MILWAUKEE,'WISCONSI1\T, ASSIGNOB T0 KoEI nING com PANY, or M LWAUKEE, wIseoNsIN, A CORPORATION.

BOOM-BOISE SAFETY MEANS.

Original application filed March 17, 1927, Serial No. 176,067. Divided and this application filed February 1, 1928. Serial No. 251,108.

This application is a divisional case of my copending application, Serial No. 176,067, filed March 17, 1927 and relates to safety apparatus to be included in the structure of crane hoists. In the copending application referred to, I have fully set out the means for discontinuing delivery of power upon the load on the boom exceeding a certain safe limit. This is carried out by short circuiting the power source whether it comprises a gasoline plant or electrical motor, as the short circuiting may take place in the ignition system of a gasolene power plant.

This invention is directed more particularly to safety means that will function to discontinue delivery of power to the crane should the boom thereof be peaked past a certain predetermined safe angular position,-

and this means is incorporated with the overloading safety means aforesaid and like the latter, functions by short circuiting the power plant.

In attaining the end set forth, I avail of certain inherent characteristics of a crane construction to provide the. desired short circuiting of the electrical system included in the power plant. This feature is the variation of the distance between the boom hoist cable and the boom. with variations in the angular position of the boom. By positioning a contact on the boom hoisting cable and including a second contact in the structure of the boom in spaced relation with the first mentioned contact, these members will remain spaced apart so that the operation of the machine is in no way interfered with so long as the boom stays within the limits of safety as regards its angular position, but should the boom become peaked too high. the con tacts aforesaid come together and thereby short circuit the electric circuit controlling the power plant. a

Further and more detailed objects and advantages will in part become apparent and in part be hereinafter stated as the description of the invention proceeds.

For a full and more complete understanding of my invention, reference may be had to the following description and accompanying drawings, in which Figure 1 is a view in side elevation, somewhat diagrammatic of a crane'construction including the boom hoist safety means provided for by this invention, the crane being shown in operating position.

Figure 2 is a view similar to Figure 1 showing the boom peaked past the safety limit and the operation of the crane thereby discontinued. I

\"Vhile a preferred form of the invention is herein set forth, it is to be understood that I am not to be limited to the exact construction illustrated and described because various modifications of these details may be provided in putting the invention into practise within the purview of the appended claim.

A crane body is shown in the drawing somewhat diagrammatic and designated by the reference character A. This crane body is pivotally mounted in the conventional manner on a tractive support B. A boom C is operated by a boom hoist cable D and may carry at its outer extremity any working tool such as a clam shell bucket E. The crane body A is mounted on its traction support so that it functions to counterbalance the weight of the boom C, together with any load sustained thereby. Obviously, a highly unsatisfactory condition would result were the boom peaked past a certain safe limit as the weight of the crane body A would then not be counterbalanced. To inhibit this condition I provide a contact 1 which is in appropriate connection with the electrical circuit included in the power plant of the crane body. If the power plant comprises an integral combustion engine, the ignition system is usually grounded to the frame work of the machine. An engagement of the contact 1 of the boom hoist will therefore discontinue op eration of the power plant through the medium of short circuiting the electrical circuit thereof.

Should the power plant comprise an electric motor, a second contact may be carried by the boom C and insulated therefrom that is adapted for cooperation with the contact 1 to short circuit the motor when the condition arises for'such action.

The contact 1 may be carried in any suitable manner by the cable D such as by the bail members 2 encircling the cable. Such a connection permits of relative movement between the contact 1 and the cable D.

As set out in my copending application, the subject matter of this application may be ed boom and a boom hoist cable, and means carried by the boom hoist cable adapted for 10 contact -With the boom when the boom reaches its highest point of safe peaking, to discontinue operation of the boom from the source of power.

In testimony whereof I aflix my signature.

ERICH H. LICHTENBERG.

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