US2700368A - Machine for automatically varnishing electrical resistors - Google Patents

Description

Jan. 25, 1955 Filed May 5, 1952 V. A. WOODELL ET AL MACHINE FOR AUTOMATICALLY VARN ELECTRICAL RESISTORS ISHING 2 Sheets-Sheet l IN VEN TOR5.

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Pda/ I? Hanan 0y v. A. woom-zu. EIAL 2,700,368 MACHINE FOR AUTGMATICALLY VARNISHING Y ELECTRICAL RESISTORS 2 Sheets-Sheet 2 Jan.25, 1955 Filed May 5, 1952 [FET- I. M I 0 a/dz g l I .WAZZZl/i/l/ V/l/A United States Patent MACHINE FOR AUTOMATICALLY VARNISHING ELECTRICAL RESISTORS Victor A. Woodell, Atehison, Kans., and Paul R. Hannaway, Independence, Mo., assignors to Electra Manufacturing Company, Kansas City, Mo., a corporation of Missouri Application May 5, 1952, Serial No. 286,048

Claims. (Cl. 118-316) This invention relates to the manufacture of relatively small articles and has to do primarily with a machine for automatically coating the articles with a fluid, thereby eliminating the necessity of a large number of workmen and assuring an even distribution of the coating substances on each of the articles themselves. I

More particularly, the invention hereof relates to the manufacture of electrical resistors. As one of the necessary steps in the production of electrical appliances of this character, each resistor must be varnished to completely cover the outer surfaces thereof rather evenly.

It is accordingly the most important object of the present invention to provide an automatic machine for feeding the resistors singly to a coating station wherein the resistor is sprayed with a suitable varnish, and thereupon removed from the spraying station and deposited upon a conveyor for advancing the same away from the coating station.

Another object hereof is to provide means for continually and successively depositing a number of resistors singly upon a support within a varnish spraying station coupled with means capable of receiving the resistors singly and removing the same from the spraying station before successive resistors are deposited within the stream of sprayed liquid.

Other objects hereof include the way in which means in provided for automatically pumping a varnishing fluid and directing the same against the resistor while it rests within the spraying station; the way in which the varnish is permitted to drain from each resistor and the droplets removed; the way in which a specially formed endless conveyor is provided to receive the resistors and advance the same to successive conveying means; and many more minor objects, all of which will be made clear as the following specification progresses.

In the drawing:

Figure l is a top plan view of the machine for automatically varnishing electrical resistors made in accordance with the present invention.

Fig. 2 is a side elevational view thereof.

Fig. 3 is an enlarged, fragmentary, vertical, crosssectional view taken substantially through the longitudinal axis of the conveyor.

Fig. 4 is a fragmentary, cross-sectional view taken on irregular line IV-IV of Fig. 3.

Fig. 5 is an enlarged, detailed, cross-sectional view taken on line V-V of Fig. 3; and

Fig. 6 is an enlarged, detailed, cross-sectional view taken on line VIVI of Fig. 3.

Electrical resistors 10, to be coated or varnished through utilization of the automatic machine about to be described, are illustrated in Figs. 3 to 6 inclusive of the drawings. Resistors 10 are each provided with a pair of opposed leads or pigtail wires 12 at the ends thereof, which wires are to be maintained free of the varnishing substance, although it is of no consequence if a short length thereof adjacent the resistor itself, receives some of the coating substances. i

Apparatus not herein shown and forming no part of the present invention, is provided to automatically and continuously feed or advance the resistors 10 to the varnishing machine of this invention, and for purposes of illustration, a small chute or platform 14 is shown having a plurality of resistors 10 thereon for movement toward the feeding portion of the present machine herein broadly designated by the numeral 16.

Feeder 16 is rotatably mounted within a pair of upice standing legs 18 and 20 of a frame 22 having a bight or lowermost wall 24. Feeder 16 includes a pair of spacedapart, preferably circular, flat discs 26 coaxially mounted on a common shaft 28 and held in spaced-apart relationship by means of a collar 30 on the shaft 28. As aforementioned, the shaft 28 spans the distance between the legs 18 and 20 of frame 22 within which it is rotatably mounted, and holds the feeder 16 substantially midway between the legs 18 and 20 as illustrated in Fig. 1 of the drawings.

The two discs 26-26 of the feeder 16, are each provided with a plurality of notches 32 having inclined trailing portions 34, feeder 16 normally traveling as indicated by the arrow in Figs. 2 and 3. The length of the collar or spacer 30 and, accordingly the distance between the discs 26-26, is slightly greater than the over-all length of the resistors 10 as shown in Figs. 4 and 5 of the drawings.

The feeder 16 chosen for illustration is provided with four equally spaced notches 32 and there is associated with each notch 32 of each disc 26 on the outer faces of the latter, a substantially L-shaped dog 36 swingably secured to its disc 26 by means of a pivot pin 38. One of the legs of the dog 36 is provided with a small notch or indentation 40 and the dogs are so balanced as to maintain substantially the position shown in Figs. 2 and 3 of the drawnigs wherein the longitudinal axis of the other leg thereof is vertical. Thus, the dogs 36 move into and out of partial overlapping relationship with the notches 32 as the feeder 16 rotates for reasons hereinafter to be made clear.

A device which may be termed for the present purposes a remover, is broadly designated by the numeral 42, and is similar to the feeder 16 in that the same comprises a pair of spaced, parallel, substantially circular discs 44. The distance between the discs 4444 is slightly greater than the distance between the discs 26-26 and such spacing is maintained by a collar 46 between the discs 44-44 and mounted on a shaft 48. Shaft 48 is likewise rotatably carried by the legs 18-20 of frame 22 for rotation on an axis parallel with and in the same horizontal plane as the axis of rotation of shaft 28.

Feeder 16 and remover 42 are in side-by-side relationship and the latter is adapted to receive the resistors 10 and particularly the wires 12-12 thereof by virtue of notches 50 in each disc 4444 respectively and equal in number to the notches 32. A triangular-shaped extension or ear 52 extending outwardly from the periphery of each disc 4444, is disposed adjacent and in trailing relationship to each notch 50 respectively.

A coating station 54 in the nature of an upstanding, polygonal tube having the upper and lowermost ends thereof open, is disposed between the feeder 16 and the remover 42. The tubular coating station 54 has a pair of opposed, vertical side walls 56-56 disposed between the discs 2626 and accordingly, disc 44-44 as shown in Fig. 4 of the drawings, each wall 56-56 having a V-shaped notch 58 at the uppermost end thereof terminating at the apex thereof in a vertical slot 60.

A pin 62 shown most clearly in Fig. 5, joins the walls 56-56 immediately below the slots -60. The tubular coating station 54 extends through an opening 64 in the bottom wall 24 of the frame 22 communicating with a container 66 for varnish or other coating substance 68, the container 66 having a fill-plug 70. The container 66 has a pump assembly 72 therein, the piston whereof is in turn provided with an upstanding, spring-loaded stem 74. A pair of conduits 76 communicating with the housing of pump 72 extend upwardly into the tubular station 54, each terminating in a perforated manifold 78 adjacent the slots 60. Thus the conduits 76 are substantially T-shaped and the perforations of the manifolds 78 are disposed to direct the fluid 68 in the form of a spray against a resistor 10 when the same is within the coating station 54 as illustrated in Figs. 3 and 4.

A conveyor 80 extending between the discs 44 of remover 42, is of endless nature and trained about a pair of spaced sprocket wheels 82 and 84, the former of which is in turn carried by a shaft 86 within the horizontal plane of shafts 28 and 48 and rotatably carried by the walls 18 and 20. The sprocket wheel 84 is mounted on a shaft 88 that is in turn supported by a pair of uprights 90. Shaft 88 is likewise provided with a pair of sprocket wheels 92, each carrying an endless conveyor 94, the conveyors 2d obviously passing over additional sprocket wheels not shown and spaced from the shaft 38.

Conveyor 80 is in the nature of a chain having a plurality of links 96 joined by pivot pins and each provided with a pair of substantially Z-shaped brackets )8, see Fig. 6, having notches 1%. The legs of the brackets 98 having notches 100 therein, are joined by a crosspin 102 immediately below the notches 111 0. Guide means to assure transfer of resistors 16 from the conveyor 80 to the conveyors 94 includes a pair of rods 1% between the conveyors 94 and inclined downwardly from a point adjacent the conveyor 86 as shown in Figs. 1 and 2. The guide rods 1% embrace the brackets 98 and terminate at the uppermost ends thereof immediately below notches 100 as the same successively pass the rods 194, it being understood that the conveyor 80 travels in the direction of the arrow of Fig. 2.

A common means not shown, may be provided to advance the conveyors 3t and 94 in the same direction and rotate the feeder 16 and remover 42 in the same direction. Assuming that a prime mover is coupled with the shaft 88, rotation of the latter will rotate the sprocket Wheels 84 and 92. As the conveyor 84) drives sprocket wheel '32 and accordingly the shaft 86, the remover 42 will be rotated by virtue of a train of gears 106 joining the shafts 86 and 48. Feeder 16 is rotated by means of a train of gears 1% interconnecting the shafts 23 and 48.

The pump of assembly 72 is actuated by means of a piston not shown, within a cylinder 11E carried by the wall above the spring-loaded stem 74. The piston within cylinder 110 has a vertically reciprocable plunger 112 depending therefrom in alignment with the stem '74, and such piston is adapted to be driven by compressed air directed to the cylinder 110 by means of a hose 114. A second hose 116 is connected with a source of compressed air not shown, and both hoses 114116 are joined with valving means 118.

Valve 118 is operated by an electrical solenoid 120 having connection with the valving means 118 by means of its reciprocable core 122. An electrical switch 124 for closing a circuit through the solenoid 120 has its spring-like actuating arm within the path of travel of a multiple cam 126 that is secured to the shaft 48 for rotation thereby. The parts are shown in Fig. 2 of the drawings with cam 126 closing switch 124, thereby energizing the solenoid 120, opening the valving means 118 and supplying compressed air to the cylinder 110. This forces the plunger 1'12 downwardly to actuate the stem 74 and thereby pump fluid from the container 66 upwardly through the conduits 76 and thence from the spray heads or manifolds 78.

A drip pan :128 in the nature of a sump, is disposed in underlying relationship to the conveyor 80.

During operation by virtue of a common prime mover coupled with the shaft 83, the conveyors 8t) and '94 operate continuously and the feeder 16, the remover 42 and the cam 126, rotate continuously. With the resistors 10 available on the chute 14 at all times to the feeder 16, as soon as a notch 32 moves to a position adjacent the chute 14, a resistor 10 will move into position between the discs 26 as shown in Figs. 3 and 4. In other words, the opposed wires 12 of resistors 10, bear against the peripheries of discs 26 and notwithstanding the inclined portions 34 of the notches 32, a resistor 10 will be maintained in a notch 32 by operation of the associated dog 36. The indentation 40 of dogs 36 underlie each of the wires 12 until the feeder 16 moves the resistor 10 toward the uppermost end of its path of travel.

As shown in Fig. 3 of the drawings, the dogs 36 automatically swing away from the corresponding notches 32 and a resistor 10 therein after leaving the chute 14. Resistor 10 is carried downwardly toward the station 54 and as soon as the wires 12 come :into contact with the proximal inclined edges of notches 58, resistor 10 will be pulled or forced from the opposed notches 32 of discs 26 and the wires 12 will ultimately'fall into the slots 60. It is noted that the resistor 10 itself is always disposed between the discs '26 and thence between the walls 56.

.Almost simultaneously with the dropping of a resistor 16 4 pressed air to the cylinder 110. Pump 72 will furnish a supply of liquid to the conduits 76 and the resistor will be sprayed with a coating of varnish or the like 68.

It is noted that the four notches 50 of the remover 42 are offset slightly with respect to the notches 32 of feeder 16. Accordingly, just before another resistor 10 is fed to the station 54 by the feeder 16, the remover 42 will receive the varnished resistor 19 and carry the same upwardly and laterally to the conveyor 80. The projections 52 move into underlying relationship to the wires 12, whereupon the latter move into the notches 50. As the varnished resistor approaches the conveyor 80, they will be forced into notches 10b of one of the pairs of brackets 98, conveyor 80 thereupon carrying the resistors 10 as shown in Fig. 3 toward the conveyors 94. As the resistor approaches the guides 124-, the wires 12 will come into contact with the upper ends of rods 104 and be stripped from the notches for deposit upon the conveyors 94. An even coating of varnish is assured by virtue of the fact that the same is free to drip therefrom, not only in the station 54, but as the resistors 10 are advanced .by conveyors 8t and .94.

Normally, one or more small droplets collect along the lowermost edge of the resistors 15 these droplets being removed by the pin 62 and by the series of pins 102. All excess liquid within the liquid station 54 gravitates to the container 66 and the drippings from the conveyor 80 are collected by the sump 128.

By virtue of the plurality of spaced-apart pairs of brackets 98, and by virtue of the particular nature of the remover 42, the resistors 16 are held spaced-apart a sufiicient length of time to avoid disturbance of the varn-ish thereon until the latter has dried to a point where interengagement between the resistors will produce no adverse effect. After the resistors 11 are deposited on a conveyor 94, a slight interengagement therebetween will not effect the resistances of the coated electrical elements since the varnish will have become partially dried. It is contemplated that the conveyors 94 be relatively long so as to lengthen the drying time and, in this connection, it may be advisable to provide a series of conveyors to successively receive the resistors by means of the wires 12 thereof until the same are sufficiently dry to permit further handling.

It .is :now seen that the machine hereof is entirely auto matic, requiring no operator attention whatsoever, and that the resistors themselves are not handled nor engaged so as to prevent an even coating of the varnish thereon. This particular operation in the manufacture of electrical elements of this kind, can thus be speeded up tremendously and a more perfect coating thereby produced.

These factors are extremely important in precision articles of this nature wherein resistance values must be maintained within close limits and, while the machine hereof may be used for coating many differing types of articles .of manufacture, other resistors or other electrical elements, such changes and modifications as fairly come within the spirit of the invention as defined by the scope of the appended claims, are contemplated hereby.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. In an article coating machine, article feeding apparatus including a rotatable element having a number of article-receiving means thereon; a coating station having an article support disposed to receive an article as the same gravitates from said means; structure for forcing a coating substance against the articles While the same is resting .on said support; and means for successively lifting said articles-singly from the support and thereupon removing the s'am'efrom the station after the articles have been coated with said substance and prior to deposit of a successive article on the support, said last mentioned means including a second .rotata'ble element having a plurality of article-receiving means thereon.

.2. A machine for varnishing electrical resistors of the kind having a pair of opposed wires, said machine comprising a rotatable feeder provided with a number of resistor-receiving means adapted to discharge resistors therefrom by .force of gravity .as the feeder is rotated; a varnishing station having a resistor support disposed to'receive a single resistoras it gravitates from the feeder; means for-directing varnish to the resist-or while thesame is :on the support; a rotatable rem-over provided with .a number of resistor-receiving means for lifting the varnished resistor tfrom said support and :advancing the same away from the station, said resistor-receiving means for the feeder and for the remover each comprising wirereceiving openings formed in the feeder and in the remover respectively, said feeder and said remover each having a pair of discs spaced to receive the resistors therebetween, said openings consisting of notches formed in the discs; means for rotating the feeder and the remover in synchronism.

3. A machine for varnishing electrical resistors of the kind having a pair of oppositely extending wires, said machine comprising a feeder and a remover mounted for rotation in the same direction and each including a pair of discs, spaced to receive resistors therebetween, there being a number of notches in the discs adapted to receive said wires of the resistors; a varnishing station having a resistor support including wire-receiving notches disposed Within the path of travel of the wires as the feeder is rotated to strip the resistors successively from the feeder; means for driving the feeder and the remover to successively deposit resistors on said support and remove the same, said support being disposed to hold the resistor thereon Within the path of travel of the remover whereby the latter strips the resistors from the support; and means for forcing varnish against the resistors While the same are on the support.

4. A machine for varnishing electrical resistors of the kind having a pair of oppositely extending wires, said machine comprising a feeder and a remover mounted for rotation in the same direction and each including a pair of discs, spaced to receive resistors therebetween, there being a number of notches in the discs adapted to receive said wires of the resistors; a varnishing station having a resistor support including wire-receiving notches within the path of travel of the wires as the feeder is rotated; means for driving the feeder and the remover to successively deposit resistors on said support and remove the same; and means for forcing varnish against the resistors while the same are on the support, said station being embraced by the feeder and the remover.

5. A machine for varnishing electrical resistors of the kind having a pair of oppositely extending Wires, said machine comprising a feeder and a remover mounted for rotation in the same direction and each including a pair of discs, spaced to receive resistors therebetween, there 'being a number of notches in the discs adapted to receive said wires of the resistors; a varnishing station having a resistor support including wire-receiving notches within the path of travel of the wires as the feeder is rotated; means for driving the feeder and the remover to successively deposit resistors on said support and remove the same; and means for forcing varnish against the resistors while the same are on the support, said station being embraced by the feeder and the remover, and the discs of the feeder and the remover being in substantially edge-t0- edge relationship.

References Cited in the file of this patent UNITED STATES PATENTS 1,030,636 Beadle June 25, 1912 1,062,001 Hall May 20, 1913 1,382,149 Walker June 21, 1921 1,700,697 Draper Jan. 29, 1929 1,874,568 Melville et a1 Aug. 30, 1932 2,283,615 Skinner et al May 19, 1942 2,363,487 Anderson Nov. 28, 1944

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