US2734121A - dicome - Google Patents

Description

H. C. DICOME 2 Sheets-Sheet l Feb. 7, 1956 METHOD AND MEANS FOR ASSEMBLING ARTICLES Filed May 11, 1953 Feb. 7, 1956 H. c. DICOME METHOD AND MEANS FOR ASSEMBLING ARTICLES 2 Sheets-Sheet 2 Filed May 11, 1953 INVENTOR. IJERMHN C. DICONE H #orngy United States Patent lVlETHOD AND MEANS FOR ASSEMBLING ARTICLES Herman C. Dicome, Pittsburgh, Pa., assignor to Edwin L. Wiegaud Company, Pittsburgh, Pa., a corporation of Pennsylvania Application May 11, 1953, Serial No. 354,152

3 Claims. (Cl. 219-38) The present invention relates to a method of providing an elongated body with a radially extending shoulder and to an article of manufacture produced thereby, more par ticularly to a method of securing a radially extending shoulder to a sheathed-type electric heater and to the heater produced thereby, and the principal object of my invention is to provide new and improved methods and articles of the character described.

In the past, the manufacture of sheathed-type electric heaters with radially extending shoulders for purposes such as locating the heater with respect to a fixed point was an expensive and time consuming operation. These shoulders were usually welded or brazed to the sheath of the heater, a costly operation as will be understood. Furthermore, many of the so constructed heaters were rejected or failed in service because of a faulty bond between the shoulder and the heater sheath.

My invention provides a sheathed-type heater with an accurately located, radially extending shoulder that is quickly, inexpensively, and permanently affixed thereto. These and other advantages will become apparent from a study of the following description and of the drawings appended hereto.

In the drawings accompanying this specification and forming a part of this application there is shown, for pur pose of illustration, an embodiment which my invention may assume, and in these drawings:

Figure 1 is a fragmentary perspective view of a sheathed-type electric heater formed in accordance with my invention, and

Figures 2, 3 and 4 are progressive stages of the operation employed in producing the heater illustrated in Figure 1.

As best shown in Figure 1, an electric heater having the usual sheath 11 filled with compacted refractory ma terial 12 has a conventional terminal pin 13 extending from the end thereof. It is to be understood that only one end of the heater 10 has been shown since both ends may be similar. It is also to be understood that in accordance with the usual practice, each terminal pin 13 may be electrically connected interiorly of the sheath 11 to respective ends of an electric resistance wire (not shown) embedded within the refractory material 12. As illustrated, a shoulder member 14 extends radially of the heater 10 and is securely seated in an annular groove 15 formed in the sheath 11 by the following means:

In assembling the shoulder member 14 with the heater 10, the heater is first securely gripped between arcuate separable jaws 16, 16 (see Figure 2) which together provide a bore 16a for closely receiving and gripping the heater.

In the embodiment of my invention herein shown, the member 14 has a washer-like configuration, the outside diameter thereof being larger than the outside diameter of the jaws 16, 16 and the inside diameter thereof being of a size to just pass the sheath 11 of the heater. The member 14 is preferably formed of a relatively high 2. tensile strength material such as steel for a purpose to be shown.

Figure 3 illustrates the operation of securing the member 14 to the heater 10. As illustrated, a die 18, having a bore 19 of a size to just passthe jaws 1616, is adapted to be pressed downwardly over the member 14 by any suitable means. The lowermost portion of the bore 19 is enlarged at 21 to the approximate outside diameter of the member 14 and a tapering wall portion 20 connects the bore portions 19 and 21.

As will be clear, pressing the die 18 downwardly over the member 14 while the member is supported by the surface 17 will exert a tremendous radial force upon the periphery of the member thus compressing it toward the sheath 11. As before mentioned, the member 14 is formed of high tensile strength material to eliminate any possibility of shearing the periphery of the member. Compressing the member 14 radially toward the sheath 11 will reduce the inside diameter of the member and force the aperture defining portion thereof into the adjacent wall surface of the sheath 11. This will in turn reduce the diameter of the sheath at this point to provide an annular groove in which the member 14 is tightly seated. It has been found that the preceding operation has a tendency to slightly increase the thickness of the member 11; however, this increase in thickness may be easily calculated and compensated for if desired.

After securing the member 14 to the sheath 11, the heater 10 may be easily removed from the jaws 16-16 by first raising the die 18 (see figure 4) and then moving the jaws 16-16 away from each other to the position illustrated. This permits easy removal of the completed heater 10 from the jaws and permits insertion therebetween of another heater to initiate a repetition of the foregoing assembly operation.

In view of the foregoing it will be apparent to those skilled in the art that I have accomplished at least the principal object of my invention and it will also be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described, hence it will be appreciated that the herein disclosed embodiment is illustrative only, and that my invention is not limited thereto.

I claim:

I. The method of forming a fixed shoulder at a predetermined distance inwardly of an end of an elongated tubular metallic body, which comprises clamping a holding member about the outer side of said body to firmly hold the same and to provide a ledge surface extending peripherally about said body side at a predetermined distance inwardly of said body end, disposing a close fitting washer-like member about said body in position resting against said ledge surface, and relatively moving said holding member and a recessed die member to move a progressively constricting die surface in a direction toward said ledge surface and in radial pressing relation against the outer peripheral edge of said washer-like member with suflicient force to indent the inner peripheral edge of said washer-like member into the adjacent wall portion of said body.

2. The method of forming a shoulder a predetermined distance inwardly of an end of a sheathed embedded resistor electric heater of the type wherein a resistance conductor is disposed in a tubular metal sheath and has a terminal end accessible through said sheath end, and wherein the resistance conductor is surrounded by and embedded Within an electric-insulating heat-conducting refractory material which substantially fills the sheath, said method comprising clamping a holding member about the outer side of said sheath and inwardly from the sheath end to firmly hold said sheath and provide a ledge surface extending peripherally about said outer side at a predetermined distance inwardly of said sheath end, disposing a washer-like member about said sheath in position resting against said ledge surface, and moving a recessed die member in encompassing relation with said sheath in a direction axially thereof to move a progressively constricting die surface in a direction toward said ledge surface and in radial pressing relation against the outer peripheral edge of said washer-like member with sufficient force to indent the inner peripheral edge surface of said washer-like member into the adjacent wall portion of said sheath in opposition to the sheath backing provided by said refractory material.

3. An electric heating element, comprising a metal tubular sheath, a resistance conductor member having a terminal end extending through an opening at an end of said sheath, a refractory heat-conducting material within the sheath for electrically insulating said conductor member and its terminal end from said sheath, and a locating shoulder at a selected position inwardly of said sheath end, comprising a metallic washer-like member encompassing the outer periphery of said sheath at said selected position and pressed radially inwardly to force its aperture-defining marginal surface into indenting and interlocking relation with the adjacent sheath wall whereby said washer-like member is locked in selected position.

References Cited in the file of this patent UNITED STATES PATENTS

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