US3696507A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for making electric heaters
Assignee: Emerson Electric Co
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Filing: 1971-03-22
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Granted: 1972-10-10
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Expires: 1991-03-22
Abstract
Abstract An improved method, and apparatus, for forming strip heaters wherein the heating resistor is disposed in centered relation within a cake of compressed refractory material in a single operation. The invention includes a cavity in a mold in which the resistor is supported on winding pegs and electrically connected to terminals. The base of the sheet metal channel of the heater to be formed is placed in juxtaposed relation with the cavity opening, and this base is pressed toward the cavity to compress refractory material and a binder within the cavity. The winding pegs are withdrawn from the mold cavity during the pressing operation to strip the resistor therefrom and leave the latter centered in the compressed cake of refractory material contained within the heater channel.
Inventors
- 👤 Robert W Unger
- 👤 Wallace H Sunderman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:24
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/20; H05B3/22; H05B3/28; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49083; Y10T29/49087; Y10T29/49089; Y10T29/49091
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
162 words
The method of forming an electrical heating element of the strip heater type which has a sheet metal channel at least in part enclosing the heating resistance and the insulating material therefor, comprising disposing terminal pin means and winding peg means in a mold cavity which is of dimensions corresponding to that of said channel, winding a resistance wire around said peg means and in electrical circuit with said terminal pin means, and extending flatwise of but spaced from the bottom of said cavity, placing granular refractory material and a binder in said cavity to substantially fill the same, disposing the sheet metal channel of the strip heater to be formed over said mold cavity with the inner surface of the base of the channel in juxtaposition relative to the cavity, and pressing the base of said channel toward said mold cavity, to compress the refractory material therein while withdrawing said peg means from said cavity to strip said resistance wire therefrom.
Claim 2
Independent Claim
162 words
The method of forming an electrical heating element of the strip heater type which has a sheet metal channel at least in part enclosing the heating resistance and the insulating material therefor, comprising disposing terminal pin means and winding peg means in a mold cavity which is of dimensions corresponding to that of said channel, winding a resistance wire around said peg means and in electrical circuit with said terminal pin means, and extending flatwise of but spaced from the bottom of said cavity, placing granular refractory material and a binder in said cavity to substantially fill the same, disposing the sheet metal channel of the strip heater to be formed over said mold cavity with the inner surface of the base of the channel in juxtaposition relative to the cavity, and pressing the base of said channel toward said mold cavity, to compress the refractory material therein while withdrawing said peg means from said cavity to strip said resistance wire therefrom.
Claim 3
Independent Claim
173 words
The method of forming an electrical heating element of the strip heater type which has a sheet metal channel at least in part enclosing the heating resistance and the insulating material therefor, comprising disposing a pair of terminal pins and at least two winding pegs within the cavity of a mold which has dimensions corresponding to said channel, supporting said terminal pins and pegs to extend transversely of the base of said cavity, winding a resistance wire around and between said pegs and terminals and extending flatwise of but spaced from the bottom of said cavity, placing granular refractory material and binder in said cavity to substantially fill the same, disposing the sheet metal channel of the strip heater relative to said cavity so that the inner surface of the channel base is in juxtaposition with respect to the cavity opening, pressing said channel base toward said cavity to compress the refractory material therein, and withdrawing the support of said terminal pins and winding pegs as said channel base Compresses said refractory material.
Claim 4
Independent Claim
173 words
The method of forming an electrical heating element of the strip heater type which has a sheet metal channel at least in part enclosing the heating resistance and the insulating material therefor, comprising disposing a pair of terminal pins and at least two winding pegs within the cavity of a mold which has dimensions corresponding to said channel, supporting said terminal pins and pegs to extend transversely of the base of said cavity, winding a resistance wire around and between said pegs and terminals and extending flatwise of but spaced from the bottom of said cavity, placing granular refractory material and binder in said cavity to substantially fill the same, disposing the sheet metal channel of the strip heater relative to said cavity so that the inner surface of the channel base is in juxtaposition with respect to the cavity opening, pressing said channel base toward said cavity to compress the refractory material therein, and withdrawing the support of said terminal pins and winding pegs as said channel base Compresses said refractory material.
Claim 5
Dependent Claim
26 words
The method of claim 2 wherein the support of said terminal pins is withdrawn at a rate uniform with the pressing movement of said channel base.
Claim 6
Dependent Claim
36 words
The method of claim 2 wherein the support of said winding pegs is initially withdrawn at a rate proportional to the initial pressing movement of said channel base and thereafter is withdrawn at a faster rate.
Claim 7
Dependent Claim
33 words
The method of claim 4 wherein the support for the winding pegs is withdrawn at said proportional rate for only a very short period as compared to the withdrawal at said faster rate.
Claim 8
Dependent Claim
59 words
The method of claim 2 wherein the support for said terminal pins is withdrawn at a rate uniform with the pressing movement of said channel base, and wherein the support of said winding pegs is initially withdrawn at a rate of about half the initial pressing movement of said channel base and thereafter is withdrawn at a faster rate.
Claim 9
Dependent Claim
235 words
Apparatus for encapsulating the heating resistance of a strip heater in refractory material in the sheet metal channel of the heater, comprising a mold having a cavity of dimensions corresponding to those of the channel of the heater to be formed with opposite sides of the cavity open, means for supporting a pair of terminal pins and at least two winding pegs within said cavity for movement transverse to the base of the same, a resistance wire wound around said pegs and electrically connected to said terminal pins and extending flatwise of but spaced from the cavity base, granular refractory material and a binder within said cavity and substantially filling the same and surrounding said resistance wire and the inner ends of said terminal pins and winding pegs, a sheet metal channel of a heater to be formed having its base rectilinearly aligned and in juxtaposition with the cavity opening and its legs adapted to fit on opposite sides of said cavity, means for pressing said channel base toward said cavity to compress the refractory material therein, the inner extremities of said terminal pins being moved transversely of said cavity base to substantially centered position by said compressing action, and means operative during the pressing operation to withdraw said winding pegs from said mold cavity to strip the resistance wire therefrom and leave the same substantially centered within and encapsulated by the compressed refractory material.
Claim 10
Dependent Claim
235 words
Apparatus for encapsulating the heating resistance of a strip heater in refractory material in the sheet metal channel of the heater, comprising a mold having a cavity of dimensions corresponding to those of the channel of the heater to be formed with opposite sides of the cavity open, means for supporting a pair of terminal pins and at least two winding pegs within said cavity for movement transverse to the base of the same, a resistance wire wound around said pegs and electrically connected to said terminal pins and extending flatwise of but spaced from the cavity base, granular refractory material and a binder within said cavity and substantially filling the same and surrounding said resistance wire and the inner ends of said terminal pins and winding pegs, a sheet metal channel of a heater to be formed having its base rectilinearly aligned and in juxtaposition with the cavity opening and its legs adapted to fit on opposite sides of said cavity, means for pressing said channel base toward said cavity to compress the refractory material therein, the inner extremities of said terminal pins being moved transversely of said cavity base to substantially centered position by said compressing action, and means operative during the pressing operation to withdraw said winding pegs from said mold cavity to strip the resistance wire therefrom and leave the same substantially centered within and encapsulated by the compressed refractory material.
Claim 11
Dependent Claim
52 words
The apparatus of claim 7, including a support for the outer ends of said terminal pins, said support being movable in the same direction as and uniformly with the means for pressing the channel base toward said cavity to thereby withdraw support of said terminal pins during compression of said refractory material.
Claim 12
Dependent Claim
66 words
The apparatus of claim 7, including a support for the outer ends of said winding pegs, said support being movable in the same direction and initially at about half the rate of movement of the means for pressing the channel base toward said cavity, and means for the thereafter increasing the rate of movement of the winding pegs support during pressing action of said refractory material.
Claim 13
Dependent Claim
36 words
The apparatus of claim 9, including a movement leverage system operable to move said winding pegs support at said half rate for only a short period of time as compared to the increased rate of movement.
Claim 14
Dependent Claim
15 words
The apparatus of claim 7, including means for increasing the length of said mold cavity.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |