US1770504A - Electrical apparatus - Google Patents

Description

July 15, 1930. c. w. WY MAN ELECTRICAL APPARATUS F iled June 20, 1927 Patented July 15, 1930 UNITED STATES PATENT OFFICE CHARLES W; WYMAN, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR TO SULLIVAN v MACHINERY COMPANY, A CORPORATION OF MASSACHUSETTS ELECTRICAL APPARATUS Application filed June 20,

My invention relates to electrical apparatus and more particularly to flame proof connections between a wall of the motor compartment and a conductor leading into the compartment.

An object of my invention is to provide an improvement in a mining machine and more specifically an improved flame proof connection between the walls of the motor section and a conductor passing therethrough. Another object is to provide an improved removable bushing between the wall of a compartment and a conductor leading into the same having means to permit removal of the bushing and conductor from outside the compartment. These and other objects and advantages will, however, subsequently more fully appear.

In the accompanying drawings I have shown for purposes of illustration one form which my invention may assume in practice. In these drawings,-

Fig. 1 is a view partly in section and partly in elevation, of parts of a mining machine having my invention embodied therein.

Fig. 2 is a detail sectional view of one of the flame proof bushings in operative position and a conductor passing therethrough.

Fig. 3 is a fragmentary sectional view of the parts shown in Fig. 2 indicating the manner in which the bushing and conductor are removed from the com artment.

In this illustrative orm of the invention my improved flame roof connection is shown associated with a mining machine of the type disclosed in a copending application to one Morris P. Holmes, Ser. No. 136,446, filed Sept. 20, 1926. As shown in Fig. 1 the numeral 4 indicates the motor section of the mining machine, and 5 the feed or control section. The cutter carrying section has nothing to do with the present invention and accordingly has not been illustrated in the drawings. The motor section 4 has in addition to the motor, a controller housed thereby, which controller is operated by a shaft 6 and a handle 7 through an intermediate flexible connection 8. Power is conducted into the motor compartment from a supply cable 9 by a connector plug 10 supported in the feed section and by 1927. Serial No. 200,268.

the power carrying wires 11. These wires 11 pass through apertures 12 and 13 in the abutting walls of the feed section and motor section respectively and have at their ends,

means for connection to the controller which in this instance take the form of grommets 14. Either of the apertures 12 and 13 may be provided with screw threads for receiving externally threaded bushings 15, each of said bushings having a bore 16 therethrough for receiving one of the power conducting wires leading into the motor compartment. It will be noted that the bores in these bushings are of a size to closely fit the conductors 11 over a relatively large area, thereby insuring that the joint between the conductor and bushing is flame proof. Bushings 15 are of insulating material.

Fig. 3 illustrates the operation of removing one of the conductors 11 and its attached grommet 14 through the apertures 12 and 13, and for this purpose it will be noted that the apertures and bushing 15 are made sufficiently large to allow free passage of one of the grommets therethrough. It is a well known fact that a screw threaded joint is very effective in preventing the passage of flame for quite obvious reasons. It is also well known that any two surfaces in direct contact over a relatively wide area form a joint which is very effective in preventing the passage of a flame, since it would be cooled and extinguished by contact with said surfaces.

As a result of my invention, it will be observed that improved means have been provided for preventing the transmission of a flame to the outside of the motor compartment in the event of an explosion therein. Also it will be observed that with my improved one piece bushing the conductors may be removed from the motor compartment through the apertures 12 and 13 which avoids the delay and expense incident to the removal of the old type of bushings and conductor where it was necessary to get into the motor compartment and remove the grommets from the power conducting wires.

While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claim.

What- I claim as new and desire to secure by Letters Patent is:

In a flame proof apparatus, a casing having a hole in the wall thereof and adapted to house an electrical device, means for making an electrical connection with a device enclosed in said casing comprising a flexible cable passing through the hole in the Wall of the casing and a grommet on the end of said cable Within said casing and of a size that will just pass through said opening and a comparatively long cylindrical bushing surrounding said cable and threaded from the outside of said easing into said opening to provide a flame proof joint between the cable and casing.

In testimony whereof I affix my signature.

CHARLES W. WYMAN.

Images