US1928636A - Pot head - Google Patents

Description

1933- A. G. STEINMAYER 1,928,636

POT HEAD Filed Oct. 14, 1929 Patented Oct. 3, 1933 POT HEAD Alwin G. Stcinmayer, Milwaukee, Wis, assignor to Line Material Company, South Milwaukee, Wis., a corporation of Wisconsin Application October 14, 1929. Serial No. 399,647

1 Claim.

As is well known in the art, pot heads are employed to keep moisture out of cables where the strands or conductors thereof are separated and come out of the sheath and this invention, which is a continuation in part of my copending application Serial No. 282,712, filed June 4, 1928, relates particularly to covers for the pot heads through which the individual conductors extend and has as its primary object to provide means for interrupting the continuity of the magnetic metal around the conductors to reduce the magnetic field which exists around the conductors at the cover.

Heretofore this magnetic field or loop has been reduced by slotting the cover adjacent each aperture through which the cable strands extend and filling the slots with lead or by forming the entire cover of an alloy or non-magnetic metal; but these methods have proven unsatisfactory. Where the cover is formed of an alloy, the cost is relatively large and when the lead filled slots are resorted to, the cost is also considerable, due to the tedious task of melting the lead into the slots. The present invention not only eiiiciently reduces the magnetic loop in an inexpensive manner, but also positively precludes the possibility of moisture entering into the interior of the pot head.

A further object of my invention, therefore, resides in the provision of a pot head having an insert of brass or other alloy cast into place.

And a still further object of this invention resides in the provision of an insert formed of nonmagnetic metal which is cast into a pot head cover or the like and which is so designed that when in place it is positively held against detachment.

With the above and other objects in View which will appear as the description proceeds, my invention resides in the novel construction, combination and arrangement of parts substantially as hereinatfer described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claim.

In the accompanying drawing I have illus trated one complete example of the physical embodiment of my invention constructed according to the best mode I have so far devised for the practical application of the principles thereof,

and in which:

Figure 1 is a view of a pot head embodying my invention, parts thereof being broken away and in section to more clearly illustrate structural details;

Figure 2 is a cross sectional view taken through the cover of my improved pot head structure taken through Figure 1 on the plane of the line 2-2;

Figure 3 is a top plan view of the cover shown detached from the pot head, and

Figure 4 is an enlarged detail perspective view of one of the inserts which is cast into the cover member.

Referring now more particularly to the accompanying drawing in which like numerals designate like parts, the numeral 5 designates the bowl or body of a pot head of usual construction and having a cover 6 detachably secured thereto by screws 7 or the like and preferably formed of cast iron. A cable 8 extends upwardly into the pot head interior, the adjacent portion of the pot head being connected with the cable sheath in any suitable manner as at 8 and the cable being composed of a plurality of conductors 9 which are separated within the pot head and are brought outwardly through apertures 10 in the cover 6. A suitable insulating member or bushing 11 is positioned within each aperture 10 of the cover to insulate the conductors 9 from the cover member 6. As is customary, the interior of the bowl 5 is completely filled with a suitable insulating compound which is inserted into the interior of the bowl through an opening in the cover adapted to be closed by a plug 12. 85

The cover being of cast iron, a magnetic loop is set up which encircles each conductor, especially when alternating current of relatively high amperage is passing through the conductors and to break up and minimize the undesirable effects of this loop, the present invention utilizes inserts 13 formed of brass or other suitable alloy and substantially double T-shaped having a tapered Web 14, a head 15, and an intermediate transverse flange 16 formed by ribs extended from oppo- 95 site sides of the web, the web 14 extending beyond the ends of the head and ilange as clearly illustrated in Figure 4.

The inserts 13 are cast into the head 6 and thus form substantially an integral part thereof, being positioned between adjacent apertures 10 and forming a continuation of the aperture peripheries. The difference in shrinkage, between the two metals, however, prevents the formation of a perfect bond therebetween which allows for a diiierence in contraction and expansion of the metals and thus eliminates the possibility of breakage, which might occur if a perfect bond existed between the two metals.

It will be noted that the transverse flanges 16 are embedded in the cover, with their bottom surfaces forming continuations of the inner surface. This construction positively prevents detachment of the insert and also strengthens it.

It is also noted that the inner edge portion of the web 14 projects beyond the adjacent surface of the cover. This facilitates the casting of the cover, as it centers the insert with respect to the mold and holds it against shifting during pouring.

From the foregoing description taken in connection with the accompanying drawing it will be readily apparent to those skilled in the art to which an invention of this character appertains that I provide a highly efiicient, positively retained, and inexpensive means for interrupting the loop of magnetic metal to reduce the magnetic field present in structures of the character described and one so constructed as to preclude the entrance of moisture to the interior of the structure. :fi

What I claim as my invention is:

In combination with a pothead cover formed of magnetic metal and having a plurality of outlets, an upstanding flange having a slot therein running between the outlets, a substantially T- shaped member of non-magnetic material fitting in said slot, means to maintain said nonmagnetic material within said slot, and downturnecl outer portions on the T-shaped member fitting around the edges of said upstanding flange to keep moisture out of the interior of said pothead.

ALWIN G. STEINMAYER.

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