US3856057A

US3856057A - Winding apparatus

Info

Publication number: US3856057A
Application number: US00270486A
Authority: US
Inventors: R Mitts; H Tyler
Original assignee: Robertshaw Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1972-07-10
Filing date: 1972-07-10
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24

Abstract

The winding apparatus of the present invention is intended for coiling an elongated strip which is rendered malleable in a predetermined temperature range. The winding apparatus includes a frame mounting a cylindrical mandrel and having first and second clamps disposed on opposite sides of such mandrel. The first clamp is carried from the frame, and the second clamp is carried from a rotary head which is rotatable to rotate the second end of the strip around the mandrel. Heating means is provided for heating the central portion of the strip to form a heated bend area adjacent the mandrel and temperature control means includes a sensor for sensing the heat of such strip in the bend area and is responsive to the temperature sensed to control the heating means to maintain such area within the predetermined temperature range whereby rotation of the rotary head will cause the strip to be progressively coiled on the mandrel to form a coil of windings held to relatively close tolerances.

Description

22 Filed;

United States Patent [191 Mitts et al. I

1 1 WINDING APPARATUS [75] Inventors: Richard K. Mitts, Fullerton; Hugh Jean Tyler, Santa'Ana, both of Calif. p

[73] Assignee:v Robertshaw Controls Company, Richmond, Va.

July- 10, 1972 211 Appl. No.: 270,486

{52 us. C1 140/102, 72/13, 72/66, 1

[ 56] References Cited UNITED STATES PATENTS 1,365,015 1/1921 Zwicker 425/DIG. 7 2,477,020 7/1949 Van Sant 72/295 2,737,224 3/1956 Jones 72/296 2,808,501 10/1957 Kilpatrick et al.. 219/153 2,920,676 1/1960 Turnblade 72/298 2,963,067 12/1960 Kelso et al. 72/298 2,975,820 3/1961 Huet 65/281 X 3,340,712 9/1967 .Iame'son 72/66 3,368,377 2/1968 Hirayama. ..72/l28 3,555,597 l/1971 Meadows, 425/DIG. 26

FOREIGN PATENTS OR APPLICATIONS 119,678 3/1945 Australia 72/342 [451 Dec.- 24, 1974 Primary Examiner C. W. Lanham Assistant Examiner-D. M. Gurle'y Attorney, Agent, or Firm-Frilwider, Patton, Rieber,

Lee 8!. Utecht s7 ABSTRACT The winding apparatus of the present invention is intended for coilingan elongated strip which is rendered malleable in a predetermined temperature range. The

winding apparatus includes a frame mounting a cylindrical-mandrel and having first and second clamps disposed on opposite sides of such mandrel. The first clamp is carried from the frame, and the second clamp is carried from a rotary head which is rotatable to ro tate the second end of the strip around the mandrel. Heating means is provided for heating the central portion of the strip to form a heated bend area adjacent the mandrel and temperature'control means includes a sensor for sensing the heat of such strip in the bend area and is responsive to the temperature-sensed to control the heating means 'to maintain such area within the predetermined temperature range whereby I rotation of the rotary head will cause the strip to be progressivelycoiled on the mandrel to form a, coil of windings held to relatively close tolerances.

18 Claims, 20 Drawing Figures 6/1943 Germany.. 72/342 7 mandrel included in the winding J -1 WINDING APPARATUS material, such as molybdenum disilicide disposed adjacent a gas jet for being electrically energized to be heated toa' high temperature for igniting thegas jet.

The'coil may then be utilized as a sensor for sensing the temperature of such gas jet to control thefuel supply thereto. In order for the resultant ignitor-sensor coil to provide an accurate indication of temperature, it is necessary to hold the mechanical dimensions thereof to relatively close tolerances during winding of the coil so current will be conducted therethrough in proportion to the temperature thereof for controlling the fuel supply in proportion to such current. It has been common practice to wind coils of wire on a disposable mandrel to form a coil to act as an ignitor but prior art devices generally fail to maintain therequired. accuracy to enable such coil to be utilized as a temperature sensor for accurately determining the temperature of a flame.

FIG. 6 is a longitudinal sectional view, in enlarged scale, taken along the line 6-6 of FIG. 4;

FIG. 7 is a detail view, in enlarged scale,'of a secondclamp included in the winding apparatus shown in FIG. 1; 7

FIG. 8 is a transverse sectional view taken along the line 88 of FIG. 7; Y

FIGS. 9 and 10 are detail views, in enlarged scale, depicting electrical contacts included in the winding apparatus shown in FIG. 1;

FIG. 11 is a schematic view of the winding apparatus shown in FIG. 1;

. Numerour prior art devices have been proposed for bending metal bars and the like and which include clamps for clamping opposite ends of such bars while a heaterheats the central portion of the bars for bending around a mandrel. However, such devices do not control the temperatures'of such bars sufficiently close SUMMARY OF THE INVENTION The winding'apparatus of present invention is characteriz ed by temperature control means includinga sensor for sensing the temperature of a strip to be wound to enable the temperature in the area of a mandrel to be maintained in a temperature range which will render the strip maleable but to prevent melting thereof.

The objects and advantages of the present invention will'become apparent froma consideration of the followingdetailed description when taken in conjunction with the accompanying drawings.

I DESCRIPTION or THE DPAWINGS FIG. 1 is-a front view, partially broken away, of a winding apparatus embodying the present invention;

FIG. 2 is a partial front view similar to FIG. 1;

FIG. 3 is a detail view, in enlarged scale, showing a apparatus shown in FIG. 1; FIGS. 4 and 5 are detail views, in enlarged scale, of

.a clamp included inthe winding apparatus shown in FIG. 12 17 are diagramatic views depicting winding of a sensor coil by the-winding apparatus shown in FIG. 1',

FIG. 18 is a diagramatic view depicting the position of a pair of clamps holding the oppositeends of a wire FIG. 20 is a perspective view of a sensor coil-wound bythe winding apparatus shown in FIG. 1.-

DESCRIPTION OF THE PREFERRED EMBODIMENT The windingapparatus of present invention includes, generally, a frame 21 having a cylindrical expandable mandrel 23 mounted thereon. Still speaking generally, a stationary clamp 25 is mounted on the frame 21 for receipt of one end of a wire 27to be coiled and a sliding clamp 29 is carried from arotary head 31 for receipt of theopposite end of such wire. A pusher peg 32 projects downwardly from the rotary head 31 to engage the wire 27 adjacent the mandrel 23. An electrical heating circuit includes electrical contactors, generally designated 35 and 37, carried by the

respective clamps l

25 and 29 for making contact with the opposite ends of the wire 27 to be coiled and an optical temperature. sensor 39 is mounted from the head 31 in position to optically sense the temperature of the wire 27 in a bend area 41 immediately adjacent the mandrel 23. Such such sensor to maintain the temperature in such area sufficiently high to maintain the wire 27 malleable "without melting thereof. Consequently, the head 31 may be rotated to orbit the sliding clamp 29 about themandrel 23 and. the-pusher 32 will coil the wire 27 about the mandrel 23 to form a close tolerance sensor coilas shown in FIG. 20.

track 51 is polished on its interior and carries a slider 47 of square cross-section, and the periphery thereof is polished to form a smooth close fit in the track 51. The slider 47 carries the moveable clamp- 29 therefrom for free shifting radially, inwardly, and outwardly along the track 51 as it is rotated by the rotating shaft 45.

The

clamps

25 and 29 are generally similar and each include a pairv of jaws 53 and 55 (FIG. 6) having a plunger 57 disposed therebetween and pivotally mounted on one extremity from a pivot screw 59. The

- jaw 55 has a V-shapednotch 6l'cut thereinto and ties of a compression coil spring 67 which urges the free extremity of such plunger 57 toward the wire 27 nesting in the V-notch 61. Through bores 71 are formed in the respective jaws 55 and receive respective one extremities of cylindrical actuating pins 73, the opposite extremities thereof being formed with a head 74 (FIG. 8). The actuating pin 73 of the clamp 25 includes a cam 75 mounted intermediately thereon for selectively driving the contactor 35 away from the adjacent end of the wire 27 upondepression of such pin, the purpose of which will appear hereinafter.

The pusher rod 32 is supported centrally from the track 51 and is formed in its lower extremity with a peripheral groove 77 which receives the wire 27 for bending thereof around the mandrel 23.

As noted hereinabove, the rotary drive shaft 45 is vertically shiftable and'is biased upwardly by means of a coil compression spring 81 which urges upwardly on a collar 83 mounted on the upper end of such shaft. An eccentric cam 85 engages the upper end of the drive I shaft 45 to control vertical shifting thereof and is driven by means of a drive motor 87 acting through a gear train, generally designated 89. The motor 87 also acts vto drive a gear 91 which accommodates vertical shifting of the drive shaft 45 but is keyed thereto for effecting rotation thereof.

1 Referring to FIGS. 1 and '3, the frame 21 includes a nected in circuit by means of an electrical lead 151, and the rotating contactor 37 is connected in circuit by means of a highly flexible pigtail lead 153 which accommodates radial sliding of the clamp 29 and contactor 37 on the radially extending track 51. I

Since molybdenum disilicide is of a nature that the. surface thereof oxidizes to a degree resulting in a coating of natural glass being formed on the periphery thereof and such coating acts as an electrical insulator, it is' impractical toobtai'n a sufficiently good electrical contact with the cylindrical periphery of such wire to enable the required heating current to be conducted therethrough. Consequently, the

contactors

35 and 37 are arranged for contacting the recently broken unoxidized ends of the wire 27 thus avoiding the glass coat which is built up on the periphery of the wire and making an electrical contact which has proven more than adequate for conducting the required ampereage.

The

respective contactors

35 and 37 themselves are in the form of electrically conductive leaf springs 116 (FIGS. 4 and 5) which are carried on one end from the respective clamps and 29 bymeans of respective mounting screws 119 and have respective relatively I clamp 25 is turned outwardly at its free extremity to pie-shaped elements 105 which define quarter circles in cross-section and'are flared outwardly at their base to form respective shoulders 107 which are received beneath a peripheral rim 111 formed at the topof the cruciform spaces defined between the expansive segments 105 whereby upward shifting thereof will expand the upper extremity of such mandrel and downward shifting of such expander will enable the upper extremity of the mandrel to collapse.

v A cooling system is provided for effecting localized cooling of the wire 27 during forming thereof and includes a cool air conduit 120 (FIG. 11) leading from an air supply 122 and teeing off to terminate at its opposite extremities in

respective manifolds

124 and 127, the manifold 124 being carried from the base 101' for disposition adjacent the stationary end of the wire 27 and the manifold 127 is carried from the rotary head 31 for normal disposition adjacent the rotating end of such wire.

The electrical heating circuit includes three

electricallyconductive slip rings

132, 134 and 135 carried on the rotary head 31 and having respective

electrical brushes

137, 139 and 141 in electrical contact therewith. The respective brushes 137, 139 and 141 are connected in circuit by means of respective leads 143, 145 and 147. The stationary electrical contactor 35 is consoft silver contactbuttons 121 mounted intermediately thereon for making positive electrical contact with the frequently rather ragged axial end of the wire 27. The free extremity of the leaf spring 116 included in the form a canted flare 123 for engagement thereunder of the retractor cam described hereinabove.

In operation, it will be realized that the molybdenum disilicide wires 27 are relatively brittle and may be conveniently broken to the desired lengths thus leaving relatively ragged and frequently pointed ends 131 and 133 as shown in FIGS. 9 and 10. It will further be appreciated that the relatively soft contact buttons 121 provide for excellent electrical contact between the respective buttons 121 and wire ends 131'and 133. The length of wire 27' to be wound into a coil is mounted in the winding apparatus, for example, by the operator grasping one end thereof with his right hand and inserting the left hand thereof into the notch 61 (FIG. 6) while the clamp actuating pin' 73 is held depressed'to maintain the free end of the clamp plunger 57 urged away from such notch. Depression of the actuating pin 73 also engages the 'retractor cam 75 with the flare 123 of the contactor '35 to maintain the leaf spring 116 urged away from itsnormal position so the wire 27 may be pressed against the contact button 121 and upon release of the actuator pin 73, the clamp plunger 57 will engage the wire 27 to hold such wire captive within the slot 61 and the pressure of the leaf spring'116 will further urge the cam 75 away from the clamp 25 thus freeing such leaf spring for pressing the contact button 121 firmly and positively against the end 131 of thewire 27 to assure a good electrical contact.

The right hand end of the wire 27, as viewed in FIG. 1, is then inserted in the sliding clamp 29 by sliding such clamp radially inwardly on the track 5l-while depressing the clamp actuating button 74 (FIG. 8) to open such clamp 29 for receipt of the right hand end of the-wire'27 in the corresponding notch 61. Referring jagged end 133 of the 'wire 27 to assure a positive electrical contact therewith.

' It. will be appreciated that theexpander 115. has been raised to expand the upper position of the mandrel 23 for housing the wire 27 formed thereon. I The electrical circuit is energized to energize the

heater contactors

35 and 37 to commence'heating of the central portion of the wire 27 while cooling air is directed from the manifolds 1'23 and 127 directly onto 2 the wire 27 on opposite sides of the optical temperature sensor 39. The central portion of the wire '27 will be heated to slightly above 2,7()0 F,- at which time the sensor 39 willsense the brightness of the wire 27 in the bend area 41 to discontinue heating thereof. It is important that the wire 27 be heated to approximately 2,700F to render malleable in the bend area 41 but care must be taken to avoidheating above the melting temperature of molybdenum disilicide, forexample, 3,000F, to avoid melting and distortion. The rotary head 31 is then' actuated to commence rotation of the track 51 to rotate the pusher peg 77 firmly against the wire 271to commence bending thereof about the upper extremity of the expandable mandrel 23. It will be appreciated that a slight heat loss from the wire 27 will result from contacting thereof by the pusher peg 32, but the sensor 39 willimmediately sense the temperature drop to again energize the

heater contactors

35 and 37 .to maintain the desired malleable temperature in the bend area 41. As the track 51 continues to rotate, the

pusher peg 32 will cause the wire 27 to be bent about the mandrel 23 asshown in FIG. 12 while the cooling

manifolds

124 and 127 continue cooling of 'such wire in the areas remote from the bend area 41. Consequently,'the ends of such wire 27 will remain relatively straight while the bend area 41 is caused to bend about the .mandrel 23 in a uniform and continuous manner.

As bending of the wire 27 continues, the cam 85 (FIG. 1) will rotate enabling the helix spring 81 to raise the drive shaft 45 gradually to thereby raise the transverse track 51 and consequently the drive peg 77 and sliding clamp 29 to form the desired pitch of the helix angle defined by the coil formed about the mandrel 23.

Thus, the portion of the wire 27 leading from the mandrel to the sliding clamp 29 will be spaced from the wire portion leading to the stationary clamp 25 (FIG; 19) at a predetermined spacing 151 so the spacing be-- tween the adjacent coils of the finished sensor (FIG. 20) are spaced at relatively close tolerance spacings to assure a highly predictable rate of heat transfer therebetween.

Continued rotation of the rotary head 31 will cause the slidingclamp 29 to continue on around the mandrel 23 past theposition shown in FIGS. 14 and to'finally assume the finished position shown in FIG.' 16. During this entire winding procedure, the sliding clamp 29 slides radially inwardly'along the track 51 as dictated 2 The

clamps

25 and 29 may then be released and the finished sensor coil then removed therefrom and such coil will be in' the condition shown in FIG. ready for installation, it being appreciated that the spacing between the windings thereof remains closely controlled without undue residual stress therein which may result in early failure due to either deformation or' actual breakage.

From the foregoing it will be appreciated that the winding apparatus of present invention provides a convenient and economical means for winding a high temperature resistant wire into a coil composed of a series of windings which areheld spaced from one another at spacings of relatively close tolerance, thus providing for a sufficiently predictable rate of heat'tr'ansfer between adjacent windings to enable the coil to be utilized in a high temperature flame to sense the changes in resistance of such coil at different temperatures of the flame to thereby enable such coil to act as a temperature sensor for connection with, circuitry for detecting suchvariance in resistance and providing a direct temperature indication.

We claim: l I 1. Precision winding apparatus for coiling an elongated strip rendered malleable in a predetermined temv perature range and comprising:

a frame;

an elongated mandrel supported by said frame;

first and second clamp means for'clamping first. and

second'ends of said strip;

a rotary head mounted from said frame and carrying said second clamp means for orbiting said second clamp means about said mandrel to progressively bend a selected bend area of saidstrip about .said

I mandrel;

drive means for rotating said'rotary head; v

pitch control means coupled with said drive means and with said rotary head to shift said rotary head vertically to control the pitch of said coil;

heating means for heating'said, bend area;

a temperature sensor disposed adjacent said mandrel and arranged to sense the temperature at said bend area; and

temperature control means connected with said heating means and said temperature sensor and operativein response to upper and lower temperature within said temerature range to control said heating means to maintain-the area of said strip sensed by said sensor within said predetermined temperature range whereby said strip may be clamped between said clamp means, said heating means actuated to heat said bend area, said rotary head ener-' gized toorbit said second clamping means and said .sensor will sense the temperature of said bend area pitch control means coupled with said second clamp 1 that inmeans to gradually shift said second clamp means axially with respect to said mandrel to control the pitch of the coil formed by said strip.

said heatingmeans includes an electrical circuit including contactor means disposed adjacent said respective clamp means for making electrical contact with the opposite extremities of said strip.

5. Winding apparatus as set forth in claim 4 wherein:

one of said contactor means includes an electrically conductive elongated spring having a free extremity including contact means engageable with one end of said strip.

6. Winding apparatus as set forth in claim 5 that includes:

contactor retractor means including cam means for selectively urging said elongated spring away from said one end of said strip.

7. Winding apparatus as set forth in claim 1 wherein:

at least one of said clamping means includes a bearing surface, a plunger and biasing means for urging said plunger toward said bearing surface to clamp said strip between said plunger and bearing surface.

8. Winding apparatus as set forth in claim 7 wherein:

said mandrel includes at least two segments and said expander means is interposed between said segments and operable upon axial movement thereof to spread said segments.

9. Winding apparatus as set forth in claim 1 wherein:

said mandrel is split to form expandable sections which expand transversely and includes expander means for expanding and contracting said sections.

of said strip. I l2. Winding apparatus as set forth in claim 1 that includes:

pusher peg means carried'from said rotaryhead-and offset axially from said mandrel for engagement of said strip adjacent said mandrel to wrap said strip about said mandrel as said head is rotated. 13. Winding apparatus as set forth in-claim 1 that includes:

an arm carried by said rotary head and projecting radially from the axis thereof to form a radial track; and mounting means mounting said second clamp means on 'said track for travel therealong as said wire is wound on said mandrel. l4. Winding apparatus as set forth in claim 1 that includes:

cooling means including conduit means formed with first and second nozzle means disposed. adjacent said first and second clamp means. 15. Precision winding apparatus as set forth in claim 1 wherein:

said temperature control means is operativeto maintain the temperature of said bend area above 2,700 F. j =16. Precision winding apparatus as set forth in claim 1 wherein: said temperature control means is operative to maintain the temperature of said bend area between 2,700 and 3,000 F. l7. Precision winding apparatus as set forth in claim ""1 wherein:

said heating means includes an electrical circuit including first and second electrical contactor means disposed adjacent said respective first and second clamp means and biasing means urging said contactor means into engagement with the opposite ends of said strip. 18. Precision winding apparatus as setforth in claim I wherein:

said clamp means are constructed of material having a high coefficient of heat transfer to act as heat sinks for said strip.

Claims

1. Precision winding apparatus for coiling an elongated strip rendered malleable in a predetermined temperature range and comprising: a frame; an elongated mandrel supported by said frame; first and second clamp means for clamping first and second ends of said strip; a rotary head mounted from said frame and carrying said second clamp means for orbiting said second clamp means about said mandrel to progressively bend a selected bend area of said strip about said mandrel; drive means for rotating said rotary head; pitch control means coupled with said drive means and with said rotary head to shift said rotary head vertically to control the pitch of said coil; heating means for heating said bend area; a temperature sensor disposed adjacent said mandrel and arranged to sense the temperature at said bend area; and temperature control means connected with said heating means and said temperature sensor and operative in response to upper and lower temperature within said temerature range to control said heating means to maintain the area of said strip sensed by said sensor within said predetermined temperature range whereby said strip may be clamped between said clamp means, said heating means actuated to heat said bend area, said rotary head energized to orbit said second clamping means and said sensor will sense the temperature of said bend area to hold said predetermined temperature range and said pitch control means will shift said head vertically to precisely control the pitch of the resultant coil.

2. Winding apparatus as set forth in claim 1 that includes: first and second cooling means disposed in heat exchange relationship with the opposite extremities of said strip to cool portions of said strip on opposite sides of said bend area.

3. Winding apparatus as set forth in claim 1 that includes: pitch control means coupled with said second clamp means to gradually shift said second clamp means axially with respect to said mandrel to control the pitch of the coil formed by said strip.

4. Winding apparatus as set forth in claim 1 wherein: said heating means includes an electrical circuit including contactor means disposed adjacent said respective clamp means for making electrical contact with the opposite extremities of said strip.

5. Winding apparatus as set forth in claim 4 wherein: one of said contactor means includes an electrically conductive elongated spring having a free extremity including contact means engageable with one end of said strip.

6. Winding apparatus as set forth in claim 5 that includes: contactor retractor means including cam means for selectively urging said elongated spring away from said one end of said strip.

7. Winding apparatus as set forth in claim 1 wherein: at least one of said clamping means includes a bearing surface, a plunger and biasing means for urging said plunger toward said bearing surface to clamp said strip between said plunger and bearing surface.

8. Winding apparatus as set forth in claim 7 wherein: said mandrel includes at least two segments and said expander means is interposed between said segments and operable upon axial movement thereof to spread said segments.

9. Winding apparatus as set forth in claim 1 wherein: said mandrel is split to form expandable sections which expand transversely and includes expander means for expanding and contracting said sections.

10. Winding apparatus as set forth in claim 1 that includes: means for expanding said mandrel for winding of said strip thereon.

11. Winding apparatus as set forth in claim 1 wherein: said temperature sensor includes optical means directed at said bend area for sensing the brightness of said strip.

12. Winding apparatus as set forth in claim 1 that includes: pusher peg means carried from said rotary head and offset axially from said mandrel for engagement of said strip adjacent said mandrel to wrap said strip about said mandrel as said head is rotated.

13. Winding apparatus as set forth in claim 1 that includes: an arm carried by said rotary head and projecting radially from the axis thereof to form a radial track; and mounting means mounting said second clamp means on said track for travel therealong as said wire is wound on Said mandrel.

14. Winding apparatus as set forth in claim 1 that includes: cooling means including conduit means formed with first and second nozzle means disposed adjacent said first and second clamp means.

15. Precision winding apparatus as set forth in claim 1 wherein: said temperature control means is operative to maintain the temperature of said bend area above 2,700* F.

16. Precision winding apparatus as set forth in claim 1 wherein: said temperature control means is operative to maintain the temperature of said bend area between 2,700* and 3,000* F.

17. Precision winding apparatus as set forth in claim 1 wherein: said heating means includes an electrical circuit including first and second electrical contactor means disposed adjacent said respective first and second clamp means and biasing means urging said contactor means into engagement with the opposite ends of said strip.

18. Precision winding apparatus as set forth in claim 1 wherein: said clamp means are constructed of material having a high coefficient of heat transfer to act as heat sinks for said strip.