US3154113A - Method of making grids intended for use in electron discharge-tubes - Google Patents

Description

Oct. 27, 1964 G. MOESKER 3,154,113

METHOD OF MAKING GRIDS INTENDED FOR use IN ELECTRON DISCHARGE-TUBES Filed April 8, 1958 INVENTOR GERARD MOESKER ME T United States Patent 3,154,113 METHOD OF MAKING GRIDS INTENDED FOR USE IN ELECTRON DISCHARGE-TUBES Gerard Moesker, Eindhoven, Netherlands, assignor to North American Philips Company, Inc., New York,

N.Y., a corporation of Delaware Filed Apr. 8, 1958, Ser. No. 727,140 Claims priority, application Netherlands Apr. 24, 1957 1 Claim. (Cl. 14071.5)

The present invention concerns a method of making grids intended for use in electron-discharge tubes or the like, by winding wire on grid backbones to form a grid subsequent to which the wire is cut apart or severed in some other way and a next grid is wound after axial displacement of the grid backbones. This may be termed winding without waste turns.

The aforesaid method is known (British patent specification 743,828).

It has now been found that this method permits, in a structurally easy manner, further important operations to be carried out on one and the same machine so as to provide a fully automatic machine delivering ready-made grids.

The method according to the invention has the feature that, after winding a grid by means of pitch tongs gripping the backbones and displacing them in axial direction so as to wind with the desired pitch(es), a second pair of tongs is made to co-act with the provisionally closed first-mentioned tongs and with the grid backbones so as to stretch them between both pairs of tongs, subsequent to which the first-mentioned pitch tongs are opened and moved back in axial direction away from the grid backbones for the next winding operation, while the second pair of tongs (stretching tongs) are opened to permit the passage of the grid backbones together with the grids for further processing. Exactly when using the method, in which the wire is each time severed and waste turns are avoided, time is available for also performing a stretching operation on the machine, while using only two pairs of tongs.

In a further important development of the method according to the invention, the grid backbones, after passing the stretching tongs, are periodically cut apart to form individual grids which are temporarily supported on a mandrel co-acting with members for deforming the grid, the mandrel being axially movable so that the deformed grid is stripped OE and removed.

The invention also has the advantage of permitting hotstretching. In hot-stretching, however, there may occur undue oxidation of the grid backbones and of the wire wound on them.

According to the invention, this oxidation can be undone on one and the same machine.

In one embodiment of the invention, in which hotstretching occurs, the grid backbones together with the wire wound on them is passed, between the stretching tongs and the cutting members, through a chamber to which reducing gas is supplied.

The machine for carrying out the method according to the invention comprises in known manner a device for feeding grid backbones, a winding head for winding wire on the backbones and arranged for severing the wire periodically and rewinding it on the backbones, and tongs for moving the grid backbones in an axial direction.

Adjacent the first-mentioned tongs (pitch tongs) a second pair of tongs (stretching tongs) is provided, according to the invention, on the side remote from the winding head, both pairs of tongs operating so as to permit the backbones to be stretched between them.

As a further development of the invention, namely "ice to perform as many operations as possible on one and the same machine, one form of the machine according to the invention, which is arranged for heating the backbones and the wire wound on them between the pitch tongs and the stretching tongs comprises a chamber supplied with a reducing gas and located between the stretching tongs and the cutting members, through which chamher the grid backbones and the wire wound on them are passed.

In order that the invention may be readily carried into effect, an example will now be described in detail with reference to the accompanying drawing, in which FIG. 1 shows the main elements of themachine in plan view,

FIG. 2 is an elevational view on a larger scale according to the arrow II in FIG. 1,

FIGS. 3 and 4 illustrate the cutting operation,

FIG. 5 illustrates the shaping of the grid, also termed ondulation,

FIG. 6 is a schematic sectional view of the slides 10 and 14 illustrated in FIG. 1,

FIG. 7 is a detailed perspective view of a cutter mechanism for actuating cutters 44 and 45 illustrated in FIGS. 1, 3 and 4,

FIG. 8 is a detailed front elevational view of a mechanism for actuating the former 20 illustrated in FIGS. 1, 2 and 5, and

FIG. 9 is a detailed perspective view of a mechanism for actuating the stripping mandrel 25 illustrated in FIG. 1, left-hand side thereof.

In a driving gear case 1, a winding head 2 is pivotally supported around a guide (not shown) for grid backbones- 3 and 4, which are unwound from a reel 5 and are superimposed, as shown in FIG. 3.

The construction of the winding head 2 is known per se (British patent specification 743,828). By means of it turns of thin wire fed by this head are wound on the backbones, preferably in notches of the backbones which are peened over later in order to secure the wire to the backbones. In a manner also known per se a number of turns required for a grid is each time wound, subsequent to which the wire is cut apart or severed in some other way and again wound on the backbones at some distance from the preceding set of turns in order to form the next grid.

From the driving gear case 1 a shaft 6 projects, which has secured to it a cam 7 which, through a roller 8 and an arm 9, drives a slide 10 comprising tongs 11 with jaws 11a and 11b adapted to be opened and closed periodically. Roller 8, arm 9 and slide 10 may be constrained against movement by a spring (not shown) which acts to return slide 10 to the position shown in FIG. 1 and thus also maintain roller 8 in contact with cam 7. These tongs 11 are termed the pitch-tongs. They are capable of gripping the backbones 3 and 4 and to impart to them a longitudinal movement, derived from the motion of the slide 10 and the cam 7, so that the wire turns obtain the required constant or variable pitch. The slide 10 is movable in a guide 12 and abuts against a stop 13.

A further slide 14 is movable in the guide 12 and comprises tongs 15 with jaws 15a and 1512 also capable of gripping the backbones 3 and 4. These tongs 15 are termed the stretching tongs.

The slide 14 is movable by the arm 16 against the action of a spring 17. The arm 16 may rest against an abutment stop 18.

A device known per se (not shown in the drawings) for burning olf wire ends projecting beyond the backbones after attachment to the backbones and severing the wire, is arranged near the Winding head 2 in the path of the backbones 3, 4 carrying the wire turns.

In this path there is further disposed between the stretching tongs and the pitch-tongs any suitable device 50 for temporarily passing current through the backbones in order to heat them together with the wire wound on them. Next to the tongs 15, the path of the grid backbones comprises a chamber 19 which is supplied with a reducing gas, for example mixed gas. The backbones 3, 4 carrying the turns are passed through this chamber, any oxidized spots resulting from the heat in hot-stretching are subjected to reduction.

From the chamber 19, the backbones 3, 4 carrying the wire turns, at the left in FIG. 1, are moved to a holder 20 containing shaping members 21, 22, 23, 24 (see also FIGS. 2 and 5) adapted to give the grid the desired shape (FIG. 5). This is effected in co-operation with a mandrel 25 which is movable in a longitudinal direction, as indicated together with the holder 39, the gear wheel 40 co-acting, for example, with a toothed rack 41 of the holder 39, and the tooth sector 43 driven by the shaft 42.

The holder 20 rotates about the shaping members 21, 22, 23, 24 and controls them with the aid of cams 31, 32, 35, 36 against the action of springs 33, 34 (FIG. 2). Arranged between the holder 20 and the chamber 19 are knives 44, 45 (FIGS. 1, 3 and 4) each time cutting apart the grid backbones 3, 4 between each two adjacent set of wire turns 46, 47, the backbones 3, 4 being guided by the mandrel 25 and centered by the shaping members 21, 22 (FIG. 3).

The knives 44, 45 may be constructed and arranged so that the cutting areas of the backbones are located slightly oifset in a longitudinal direction thereof, which is desirable for some uses of grids.

The mandrel 25 co-acts with a stripping member 37. The reference numeral 38 denotes a gutter through which the grids delivered by the machine are carried off.

The operation is as follows:

At the beginning of winding a grid, the slide occupies the position shown in FIG. 1. The tongs 11 are closed and move together with the slide 10 to the left in FIG. 1 according to a given pitch prescription. The tongs are open. After providing the number of turns required for a grid, the slide 10 abuts against a stop 13 or closely approaches it. The tongs 11 provisionally remain closed and at the same time the tongs 15 are closed. The latter together with the slide 14 are subsequently moved to the left in FIG. 1, subsequently, the grid backbones are stretched between the tongs 11 and 15 with the slide 10 resting against the stop 13.

The tongs 11 subsequently open and the slide 10 moves swiftly to the right, by virtue of a spring or other suitable known device, the tongs 11 then being closed and the tongs 15 opened, the slide 14 being drawn by the spring 17 against the stop 18.

The grid backbones 3, 4 pass through the chamber 19 and are subsequently cut, by any suitable mechanism such as illustrated in FIG. 7, thus forming individual grids, the grid cut free in this operation is supported on the mandrel 25 as illustrated in FIG. 3.

Each grid is subsequently ondulated by any suitable mechanism such as illustrated in FIGS. 2, 5 and 8, removed by means of the stripping member 37 from the mandrel 25 and carried off into the gutter or tray 38.

The common drive means for each of the various operations, i.e. cut-ting, ondulating and reciprocating mandrel 25, comprises the shaft 59 and the various cams spaced therealong and driven thereby. For purposes of a simple design for the cutter mechanism, a separate shaft 59a, parallel with and spaced from shaft 59, may be provided in a convenient location as is Well known.

What is claimed is:

In a method of manufacturing grids for electron discharge tubes wherein a grid wire is wound on continu ous backbones for a number of turns before it is severed and the backbones displaced axially and another discrete number of turns of said grid wire is wound on said backbones spaced from other discrete wire windings thereon; the method characterized by applying a first gripping means to said backbones and moving the backbones axially at a predetermined velocity to obtain a desired pitch and number of turns of said grid wire on said backbones, stopping said first gripping means, applying a second gripping means to said backbones spaced from said first gripping means at the opposite end of a discrete winding previously formed, moving said second gripping means for stretching the backbones between said first and second gripping means, releasing the first gripping means and moving the second gripping means and said backbones axially a predetermined distance While returning the first gripping means to a starting position, releasing said second gripping means and applying said first gripping means at said starting position, returning said second gripping means to a starting position, supporting the wound and stretched backbones by axially moving a mandrel means into supporting relation therewith, cutting said supported backbones between the discrete windings thereon, deforming the wound portion of said backbones while supported by said mandrel means and thereafter retracting the mandrel means supporting the deformed portion of the severed backbones to strip the mandrel means and repeating the above enumerated sequence of steps to produce discrete grid winding on continuous straightened backbones.

References Cited in the file of this patent UNITED STATES PATENTS 2,181,288 Washburn Nov. 28, 1939 2,197,533 Sutter Apr. 16, 1940 2,441,228 Schneider et al. May 11, 1948 2,727,540 Marshall et al. Dec. 20, 1955 2,837,126 Hughes et al. June 3, 1958 2,995,156 Gartner et al. Aug. 8, 1961

Images