US2458789A

US2458789A - Wire coiling machine particularly for producing coiled filaments for electric lamps and electronic tubes

Info

Publication number: US2458789A
Application number: US742276A
Authority: US
Inventors: Marter Hans
Original assignee: TECNICA APPLIC METALLI DURI ED
Current assignee: TECNICA APPLIC METALLI DURI ED; Tecnica Applicazioni Metalli Duri Ed Affini-Stama Soc
Priority date: 1946-05-18
Filing date: 1947-04-18
Publication date: 1949-01-11
Anticipated expiration: 1966-01-11
Also published as: CH266228A; BE472552A; NL66732C; GB622712A; FR943784A

Description

Jan. 11, 1949. H. MARTER 2,458,789

WIRE COILING MACHINE PARTICULARLY FOR PRODUCING COILED FILAMENTS FOR ELECTRIC LAMPS AND ELECTRONIC TUBES Filed April 18, 1947 INVENTOR HANS MA RTER a .BY ATT'Y Patented Jan. 11, 1949 WIRE COILING MACHINE PARTICULARLY FOR PRODUCING COIDED IFILAMENT S FOR ELECTRIC LAMPS AND TUBES ELECTRONIC Hans Martel, Milan, Italy,-assignor to Societa Tecnica-Applicazioni Metall-i Duri Ed Affini S. T. A. M. A., Milan, Italy, a corporationof Italy Application April 18, 1947., Serial 'No. 742,276 :Inltaly May 18, 1946 '7 Claims. 1

This invention relates to wire coiling machines, particularly to machines for producing helical filaments for electric lamps or electronic tubes, and has for its main. object to devise machines which secure more uniformly wound products than the coiling machines heretofore available.

This and more specific objects of the invention, as well as the novel means provided by the invention, are hereinafter elucidated with reference to the drawing, in which:

Figure 1 shows schematically a wire coiling machine of the general type to which the invention may beapplied, and

Fig. 2 shows in detail the essential portion of a machine embodying the invention proper.

According to Fig. 1, a horizontal hollow spindle 2 is journalled in ball bearings 3 and rapidly driven from an electromotor 4 by a belt 5 (2,000 to 3,000 R. P. M.). The mandrel wire H of iron or molybdenum passes. from a suitably braked supply reel I, at low speed (a few millimeters per second), through the spindle bore and, on leaving the discharge end of the spindle 2, is surrounded by the filament wire l2 of tungsten which passes from a winding head 6 over a guide roller to be coiled upon the mandrel. The-winding head 6 is removable from the spindle 2 and entrained by friction. Disposed near the discharge end of the spindle '2 is an exchangeable mandrel feed member or capstan l. The capstan is slowly driven through gears B, 9 from the spindle'Z'. The rough capstan surface is surrounded by one or more turns of the mandrel H in order to uniformly advance the mandrel by friction. The travelling mandrel is engaged by auxiliary guide rollers I3, l4 and passes from the capstan 1 onto a take-up reel Ill. The machine, as a rule, is equipped with accessory devices, such as a heating device for the tungsten wire, which are not essential in connection with the invention and hence not illustrated.

Machines of this kind have some deficiencies Whose detriments increase with smaller diameters of the wire to be coiled.

A calculation of the pull, normally imposed on the mandrel H between the braked supply reel l and the capstan I, shows that the elastic elongation of the mandrel, only along its working length between the spindle discharge end and the capstan,'mayreach. an order of magnitude equivalent z to about ten times the normal distance between two consecutive turns of the filament helix. It follows, thatanypermanent, periodic, or accidental variation in mandrel pull must result in a corresponding change in pitch of the wire coil Wound upon the mandrel.

This detrimental effect can be obviated only by reducing the distance of the capstan from the spindle end to the minimum. This, however, has been impossible because of the guide'roller I4 which, in the known machines, is necessary to prevent the mandrel from being bent at the spindle end when using capstans of different respective diameters to produce filament coils of differentgeometric characteristics.

According to the invention, in order to overcome thejust-mentioned deficiency, the distance between spindle end and capstan is reduced t0 a minimum. by having the mandrel pass directly from the-spindle end to the capstan, i. e. excluding' any such intermediate guiding means as the roller H! in Fig. 1, and mounting the spindle so that it can betilted about a stationary pivot axis parallel to that of the capstan.

Bymeans of the tiltable spindle, the direction in which the mandrel leaves the spindle and runs onto the capstan can readily be adapted to the different diameters of the exchangeable respective capstan members ;.v and exhibiting means may be provided for indicating ona scale the proper angular adjustment of the spindle for each of the customary diameters of an available set of capstan members.

Although the angular displacements of the spindle-necessary for'adjusting it to the different capstan'd'iameters, are relatively very small, a conventional belt transmission between drive motor'and'spindl'e is apt to show the known drawbacks of such transmissions to an increased extent. Therefore, according-to another feature of the invention, the. tiltable spindle is directly drivenby anelectromotor whose armature is mounted on the spindle, preferably so that any intermediate coupling devices are avoided and the spindle represents a part or an extension of the motor shaft.

-Wi'th atiltably mounted spindle, special care must be taken to prevent deficiencies of the wire coilduetoaxialdisplacementsofthe spindle. Even with non-tiltable-spindles journalledin highest- 3 quality ball bearings, slight axial displacements and ensuing vibrations cannot be fully prevented at the high revolving speeds of the spindle. Any

such axial displacement of the spindle causes a corresponding displacement of the point at which the tungsten wire, coming from the winding head, runs onto the mandrel and hence results in a corresponding error in the pitch of the helix. Such errors, in view of the very small pitch of the helices, may assume high relative values. With a tiltable spindle, the possibility of axial spindle displacements is increased because the pivot points of the spindle lie away from the spindle so that vibratory forces may act with an increased leverage.

According to another feature of the invention, however, the occurrence of pitch errors of the helix due to axial displacements of the spindle is avoided by assigning the guidance of the mandrel within the spindle to a separate guiding tube. This tube is inserted in the bore of the spindle and fastened so that it tilts together with the spindle but is prevented from following its revolving and possible axial movements.

The above-mentioned features and other details of machines according to the invention are apparent from the embodiment exemplified by Fig. 2. Fig. 2 is limited to showing the portion of a wire coiling machine essential from the viewpoints of the present invention, and the reference numerals in Fig. 2 are identical with those used in Fig. l for the corresponding respective elements.

According to Fig. 2, a mounting or base plate 25 carries all illustrated parts including a vertical hollow spindle 2 whose upper portion carries the armature of an electric motor 4. The roller bearings 3 for the spindle are mounted on a plate structure 2? whose portion 21a is pivoted about a shaft 28. Another portion 21b of structure 27 carries a pointer 29 for indicating on a scale 38 the proper angular adjustment of the spindle 2. The adjustment is carried out, for instance, by a hand wheel 3| through Worm gears l6 and i8. After completing the adjustment, the plate 2? is securely fastened in posi tion by tightening a hand screw 19 which passes through a slot 20 in portion 21b of plate 21. A worm 8 firmly mounted on spindle 2 between the bearings 3 meshes with a Worm gear 9 whose shaft 28 carries a pinion 33 on the other side of base plate 25. A large spur gear 34 meshes with pinion 33. The shaft 35 of gear 34 extends to the front side of base plate 25 and carries an exchangeable mandrel feeding member or capstan in proximity of the lower end (discharge end) of the spindle. A winding head 36 with the supply reel t for the tungsten wire 92 is placed on the lower end of spindle 2 to be entrained by friction. Guiding nozzles or rollers for the tungsten wire are denoted by 24. A tube is loosely inserted in the bore of the spindle, the projecting upper and lower ends of the tube being visible in Fig. 2 and denoted by 2|. The mandrel wire it is guided through the tube 21. At its upper end, the tube 2| is firmly clamped between clamping checks 22 tightened by a hand screw 23. Thus, the tube is prevented from partaking in the revolving movement of the spindle. A small hand wheel 3'! at the upper end of spindle 2 permits revolving it manually. The lower end of tube 2| is designed as an exchangeable nozzle to permit adapting the nozzle opening to different mandrel diameters and replacing worn nozzles Without having to replace the entire tube 2|.

During the operation of the machine, the mandrel ll moves slowly from a supply reel (not shown in Fig. 2) over several guide rollers, of which only one is shown at 26, to the upper end of the guiding tube 2| and through the tube. Immediately below the discharge end of the tube, the tungsten wire I2 is coiled upon the mandrel, before the mandrel surrounds the capstan I with one or more turns and travels, with the tungsten coil upon it, onto a take-up reel (not shown in Fig. 2).

If the geometric characteristics of the filament coil are to be changed, another capstan member of the corresponding diameter is placed on shaft 35, and the direction of mandrel wire as it leaves the spindle tube 2| is adapted to the new capstan diameter by tilting the spindle to a corresponding angular position shown on the scale 30. The absence of any guiding device between the spindle end and the capstan 1 permits reducing their mutual distance to a minimum so that the abovementioned drawbacks of the known machines are eliminated.

It will be apparent from the foregoing that by irtue of a tiltable mandrel guide spindle according to the invention, preferably in combination with a direct electric drive whose motor armature is mounted on the spindle and preferably with an inserted guiding tube, a considerable improvement in design and functioning is achieved with the result that the filament coils have a larger degree of uniformity and include a reduced amount of rejects as compared with the machines heretofore available.

I claim:

1. A wire coiling machine, comprising a hollow mandrel-guide spindle revolvable about its axis, a winding head disposed on said spindle near its discharge end for accommodating the wire to be coiled, a mandrel feeding member disposed near said spindle end and revolvable about an axis extending at an angle to an axial plane of said spindle, said spindle being angularly displaceable about a stationary pivot axis extending parallel to said axis of said feeding member.

2. A wire coiling machine, comprising a hollow mandrel-guide spindle revolvable about its axis, a winding head disposed on said spindle near its discharge end for accommodating the wire to be coiled, a revolvable mandrel-feeding member disposed in front of said spindle end and having an axis of revolution extending at a right angle to an axial plane of said spindle, a structure having hearings in which said spindle is revolvable and having a stationary pivot whose axis is parallel to that of said member.

3. A wire-coiling machine, comprising a hollow mandrel-guide spindle revolvable about its axis, drive means for said spindle, a winding head placed on said spindle near its discharge end for accommodating the wire to be coiled, a mandrel feeding member disposed near said spindle end and revolvable about an axis extending substantially at aright angle to an axial plane of said spindle, gear means coupling said spindle with said member for driving the latter and having a gear member whose axis is parallel to that of said member, and a structure having bearings for said shaft and being pivotally movable about said gear memberaxis to permit angularly displacing said spindle.

4. A wire-coiling machine, comprising a hollow mandrel-guide spindle revolvable about its axis, anelectromotor having an armature mounted on said spindle for driving the latter, a winding head, placed on said spindle near its discharge end for accommodating the wire to be coiled, a mandrel capstan in front of said spindle end for pulling the mandrel through said spindle, and gear means connecting said capstan with said spindle.

5. In a machine according to claim 4, said gear means having a gear member driven from said spindle and rotatable about a stationary axis, and a structure carrying said motor and spindle and being pivotally movable about said stationary axis.

6. A machine according to claim 1, comprising a tube disposed in the hollow of said spindle to be traversed by the mandrel, and fastening means disposed at the other end of said spindle and engaging said tube so from revolving while permitting it to participate in angular displacements of said spindle.

7. A machine according to claim 2, comprising as to prevent said tube- REFERENCES CITED The following references are of record in the fiieof this patent:

UNITED. STATES PATENTS Number Name Date 1,227,659 Quackenbush et a1. May 29, 1917 1,338,498 Eisler Apr. 27, 1920 1,667,677 Reufel et a1 Apr. 24, 1928 1,667,681 Shepherd et a1. Apr. 24, 1923