US3122176A

US3122176A - Method of manufacturing bodies consisting of helically wound wire

Info

Publication number: US3122176A
Application number: US847311A
Authority: US
Inventors: Dietz Johannes Jaco Franciscus
Original assignee: US Philips Corp
Current assignee: US Philips Corp; North American Philips Co Inc
Priority date: 1958-10-27
Filing date: 1959-10-19
Publication date: 1964-02-25
Anticipated expiration: 1981-02-25
Also published as: DE1119525B

Description

Feb. 25, 1964 J. J. F. DIETZ METHQD OF MANUFACTURING BODIES CONSISTING OF HELICALLY WOUND WIRE Filed Oct. '19, 1959 FIG; 2

FIG.1

R o T N E v m ohunnzs Jcrcobus franciscus dictz AGENT United States Patent 3,122,176 lvlETHOD OF MANUFACTURING BQDIES CJl SISTING 0F HELICALLY WOUND WIRE Johannes .lacobns Fran-ciscus Dietz, Eindhoven, Netherlands, assignor to North American Philips (Jompany,

lilo, New York, N.Y., a corporation of Bciaware Filed Oct. 19, 1959, Ser. No. 347,311 Qlaims priority, application Netherlands Oct. 27, 1958 2 Claims. (Ci. 14tl71.5)

This invention relates to a method of, and a device for, manufacturing bodies consisting of helically wound wire, in particular filaments for thermionic valves, electric incandescent lamps and the like, in which a wire is coiled on a mandrel and the obtained product is passed through a heating zone.

in some lamps and valves, these bodies are shaped into a form having comparatively sharp curves, for example the form of an M. The bodies show a tendency to become distorted or even to be twisted together, and this must be prevented. Hitherto, for this purpose a method has been employed comprising the steps of passing a wire coil d on a mandrel through a furnace, cutting the Wire and mandrel into lengths, arranging these lengths in boats in straightened condition and subsequently heat-treating them again so that the strains produced in the process of winding into helices (which process is also referred to as coiling process), which strains are significant in the said undesirable distortion, are relieved. Subsequently the bodies can be shaped by means of a bending machine and be further worked, for example be cataphoretically coated with a paste and sintered.

This sequence of operations requires much manual labor. Mechanization is substantially impossible.

The present invention provides a method which enables mechan zation to be effected by suitable means.

According to the invention, during the heat treatment the mandrel is twisted in a direction such that the wire coiled on it is slightly loosened.

In one embodiment of the method in accordance with the invention, the rate of twisting is matched to the speed of passage through the heating zone.

it has been found that the use of the invention enables a wire to be obtain d which is coiled on a spool and can be cut and bent automatically, after which it can be transported automatically to further operational stations, so that the entire process can be mechanized. The distortion and the twisting together of the bent wire referred to hereinbefore can be entirely prevented.

in addition, the risk of fracture of the wire at the bending points, for example the tips of the M, is reduced in that the wire is coiled more loosely on the core.

A device for c rrying out the method in accordance with the invention is provided in known manner with a take-oi spool for wl'e coiled on a mandrel, a take-up spool for tms mandrel and wire, and at least one furnace through which the wire passes on its way from the take-off spool to the take-up spool.

According to the invention, one of the spools is rotatable about an so that the wire and the mandrel can be twisted on their way between the spools.

In order that the invention may be readily carried into effect, it will now be described in detail, by way of example, with reference to the accompanying diagrammatic drawings in which,

FIGURE 1 is a front elevation of an embodiment of a device in accordance with the invention, and

FIGURE 2 is a side elevation thereof, while FIGURE 3 is an elevation of a filament bent into the form of an M, and

FIGURE 4 is an elevation of a distorted M-shaped filament.

In FZGURES 1 and 2, a take-off spool 1 is mounted for rotation on a spindle 2 which is secured to an arm 3 which, at its lower end, carries a guiding roller 4 for a wire 5 helically wound on a core, while to its upper end there is attached a disc 6 which is secured to a shaft 7 which is mounted for rotation in a bearing 7a.

The shaft 7 is driven, through a transmission comprising pulleys 8 and 9 and a cord 10, but a shaft 11, and this is again driven, through a

transmission

12, 13, 14, by a motor 15.

The wire 5 comes ofi the spool 1 and passes over roller 4 through two

furnaces

16 and 17 to a take-up spool 19 mounted for rotation on a spindle 13. The frame of the machine is designated 20.

he desired torsion of the filament between the two spools is determined by the number of revolutions of the spool 1 about the shaft 7.

It has been found that for a wire of approximately 50/, diameter, which is coiled with a pitch of about /,u on a mandrel of approximately 70/,u diameter, a rate of passage through the

furnaces

16 and 17 of 330 cms, per minute and a speed of the spool 1 about the shaft of about 700 revolutions per minute substantially prevent the distortion and the twisting together of the coiled wire at the bending points A and B (FIGURE 4) of an M-shaped filament.

This is onl an example. The twisting speed may be increased, in which event the rate of passage through the f rnace must also be increased.

What is claimed is:

i. A method of manufacturing helical wire coiled on a mandrel comprising winding said mandrel with said helical wire thereon on a take-0t spool, passing said combined mandrel and wire through a heating zone at a speed of 330 cms. per minute and thence on a take-up spool, twisting said wire between said take-oil and take-up spoois in a manner such that the wire coiled on said mandrel is slightly loosened, said combined mandrel and wire being twisted at a rate which is matched to the rate of passage through the heating zone at about 650 to 750 revolutions per minute and in such a direction that the wire coiled thereon is slightly loosened, said wire being about 50,11. in diameter coiled on a mandrel of approxi- 7'iln diameter and with a pitch of approximately 2. A device for manufacturing helical wire of about 56 in diameter and a pitch of about 80a coiled on a mandrel of a, proximately 70 1 in diameter comprising a tal1e-up spool and a take-off spool, said take-up spool and take-off spool being mounted for rotation, said helical Wire being delivered from said take-oft spool to said take-up spool, at least one furnace through which said wire is passed at a speed of approximately 330 cm. per minute on its way from the take-off spool to said take-up spool, one of said spools being rotated about an axis at about 650 to 750 revolutions per minute in a manner such that the wire together with the mandrel can be twisted on its way between the spools.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. A METHOD OF MANUFACTURING HELICAL WIRE COILED ON A MANDREL COMPRISING WINDING SAID MANDREL WITH SAID HELICAL WIRE THEREON ON A TAKE-OFF SPOOL, PASSING SAID COMBINED MANDREL AND WIRE THROUGH A HEATING ZONE AT A SPEED OF 330 CMS. PER MINUTE AND THENCE ON A TAKE-UP SPOOL, TWISTING SAID WIRE BETWEEN SAID TAKE-OFF AND TAKE-UP SPOOLS IN A MANNER SUCH THAT THE WIRE COILED ON SAID MANDREL IS SLIGHTLY LOOSENED, SAID COMBINED MANDREL AND WIRE BEING TWISTED AT A RATE WHICH IS MATCHED TO THE RATE OF PASSAGE THROUGH THE HEATING ZONE AT ABOUT 650 TO 750 REVOLUTIONS PER MINUTE AND IN SUCH A DIRECTION THAT THE WIRE COILED THEREON IS SLIGHTLY LOOSENED, SAID WIRE BEING ABOUT 50U IN DIAMETER COILED ON A MANDREL OF APPROXIMATELY 70U IN DIAMETER AND WITH A PITCH OF APPROXIMATELY 80U.