US1891943A - Method of making ground rods - Google Patents

Description

Dec. 27, 1932. B NMCK 1,891,943

METHOD OF MAKING GROUND RODS Filed July 22, 193].

' INVENTOR Patented Dec. 27, 1932 UNITED s'riATEs PATENT' OFFICE FRANCIS B. NIMICK, OF COB-AOPOLIS, PENNSYLVANIA, ASSIGNOR TO COLONIAL STEEL GOHPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA mnon or MAKING enonnn nons Application filed July 22, 1931. Serial No. 552,403.

My invention relates more particularly to ground rods such as are employed in connection; with electrical transmission lines, but is also susceptible of use in various other ways.

Ground rods frequently consist of bars which are driven into the ground to serve as anchoring posts and also as ground conductors. Conductor bars have heretofore been composed of a core or main body portion of steel or the like and a sheath or sleeve of copper or other material, the steel being employed for the purpose of strength and the copper by reason of its conductivity and noncorrosive character, but such composite bars have been commonly either square or round in cross section.

One object of my inventionis to provide a ground'rod of the type referred to, which for a given cross sectional area, has relative- 2 liy great surface area and hence greater con-' ctivity than bars of the forms heretofore employed, and which also is possessed of greater mechanical strength.

Another object of my invention is to rovide ound rods of generally improved 0 aracteristics in the way of form and eflicienc In order to permit of the clear understan ing of my invention, I have shown various features thereof in the accompanying draw- 80 ing, wherein Figure 1 is a perspective viewv of my rod at a preliminary stage in the process of forming the same; Fig. 2 isa similar view showing another form of composite blank from which ,a completed ground rod '8 may be formed; Fig. 3 is an elevational perspective view of a feeder rod formed from a composite blank shaped according to either Fig. 1 or Fig. 2, and Flg. 4 is across sectional view of the rod of Fig. 3.

While I hereinafter describe a ground rod that is ribbed, it will be understood that the rod may be fluted, grooved, or otherwise shaped to provide an exposed surface that is relatively great, compared to the cross secg tional area of the bar.

Referring to Fig. 1, a bar 4 of steel or the like, is covered by a copper sleeve or sheath 5, as by a welding operation well-known in the art, or by a combined welding and rolling or drawing operation. Again, the copper may be electrically deposited upon the steel. In any case, I have] structure wherein the core or body portion 4 possesses great strength, as in the case of steel, which can be driven into the ground, and a structure wherein the sheath 5 serves to effectively conduct electrical currents to the ground and to protect the bar 4: against corrosion, etc.

amount of metal as in its original form, there 'IS, nevertheless, a greater area of the sheath 5 exposed than in the case of the structure of Fig. 1, thus providing for greater surface contact with the ground and better electrical conductivity. Furthermore, the longitudinal ribs increase the mechanical strength of the bar as shown'in Fig. 3, relative to the strength present in the bar .of Fig. 1. This increased strength is particularly desirable, because the" rod must fre uently be driven into hard ground, and furt ermore it has in-.

creased resistance to transverse stresses.

The blank of Fig. 1 is heated to forginlfi or rollin temperature to facilitate the ro ng and s a'ping thereof as above-described.

The blank of Fig. 2 is shaped to the form shown in Figs. 3 and 4, by heating and rolling or otherwise shapin it, the end of the copper sleeve 511 being rawn to a point to completely enclose the end of the core bar 40. In other words, a rod formed from the blank of Fig. 2 will have the appearance of the rod shown in Figs. 3and 4, with the co per comletely enclosing the lower end 0 the core ar 4.

A conductor wire 6 leading from a line or structure to be grounded is placed within one of the flutes of the bar, and may be securely maintained therein in any suitable manner asby coiling a wire snugly around the round rod and the ground wire, or by suitaile clamping means such as an ordinary hose clamp.

The placing groove provi es of the ground wire 6 in a an extended electrical contact between it and the ground rod much greater than in those cases where the ound wire is simply secured against the si e of a circular or atside ground rod.

5 I claim as my invention 1. The method of making ground rods which comprises covering a hard metal bar with a close-fitting tubular sheath that is open at one end and is of more ductile metal that has high electrical conductivity, heating the composite structure to forging temperature and shaping the composite structure to form ribs extending longitudinally thereof, and to cause said ductile metal to completely enclose the said end of the said bar.

2. The method of making ground rods which comprises covering a hard metal bar with a close-fitting tubular sheath that is open at one end and is of more ductile metal that has high electrical conductivity, heating the composite structure to forging temperature and shaping the composite structure to form ribs extending longitudinally thereof, and to cause said ductile metal to com-' pletely enclose the said end of the said bar, an additional forgingoperation being performed on said end to draw it to a point.

3. The method which comprises cover' a hard metal bar with a close-fitting sheat of more ductile metal, and which is open at one end, heating the composite structure to forging temperature, rolling the composite bar toward said end, to form ribs extending longitudinally thereof and to effect elongation of the sheath relative to the bar, and compressing the said end of the composite bar to effect pointing thereof and cause the enclosure of the core point by the sheath.

4. The method which com rises coverin a hard metal bar with a close-hitting sheath 0 more ductile metal and which is open at one end, rolling the composite bar toward said end to efiectelongation thereof, and compressingsaid end of the composite bar to efiect pointing thereof and cause the enclosure 0 the core point by the sheath.

5. The method which comprises covering a cylindrical bar of relatively hard metal with a close-fitting cylindrical sheath of more ductile metal, heating the composite structure to forging temperature, appl g radially inward forging pressure to said b dr from 0posite sides thereof on two diametral lines sposed at right angles to one another, ef-

fecting elongation o the sheath relative to the bar, and compressing the composite structure near one end thereof to produce a point thereon and cause the enclosure of the core p point by the sheath.

In testimony whereof I, the said FRANCIS B. Nnnox, have hereunto set my hand.

FRANCIS B. NDHGK.

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