US3798763A

US3798763A - Method of making a rotary switch stator

Info

Publication number: US3798763A
Application number: US00335171A
Authority: US
Inventors: M Deltoer
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-03-24
Filing date: 1973-02-23
Publication date: 1974-03-26
Anticipated expiration: 1991-03-26
Also published as: FR2176593B1; CA994088A; GB1381064A; DE2307008C3; IT978703B; JPS5218391B2; DD103089A5; DE2307008B2; JPS4913678A; DE2307008A1; FR2176593A1

Abstract

A method of manufacturing a rotary switch stator in which round section wire used for the stator pins is formed into meander loops which are placed in a mold so that certain portions of the meander are held in radial formation and other portions are held in parallel arrangement whilst the intermediate interconnecting portions are within the annular cavity of the mold which is filled with liquid electrically insulating material. After the insulating material has solidified, the excess parts of the wire are cut off to leave a stator having a plurality of equi-spaced radial contact studs and the same number of parallel electrical contact members respectively connected thereto.

Description

United States Patent 1191 Deltoer Mar. 26, 1974 [54] METHOD OF MAKING A ROTARY SWITCH 3,261,929 .7/1966 Neff 200/1 1 D STATOR 3,219,785 11/1965 Allisonm 200/11 D 3,011,041 11/1961 Bakels.... ZOO/DIG. 7 [76] Inventor: Marcel Henri Deltoer, 22 rue 2 73 ,935 3 1957 Mammy mg 7 Ravon, Hauts de Seine, France 2,668,894 2/1954 Coutcs ZOO/166 CM [22] Filed: Feb. 23, I973 Primary ExummerCharles W.- Lanham 1 pp NOJ 335,171 Assistant Examiner.lames R. Duzan Attorney, Agent, or FirmStevens, Davis, Miller &

[30] Foreign Application Priority Data Moshe! 4 Mar. 24, 1972 France 7210428 [57] ABSTRACT [52] 29/630 29/597 29/622 A method of manufacturing a rotary switch stator in 29/630 zoo/166 CM which round section wire used for the stator pins is [51] Ill. Cl H01! formed into meander op which are placed in a mold [58] held of Search 29/622 630 630 597; so that certain portions of the meander are held in ra- 200/11 166 166 dial formation and other portions are held in parallel 310/237; 339/5 5 5 P arrangement whilst the intermediate interconnecting portions are within the annular cavity of the mold [561 References cued which is filled with liquid electrically insulating mate- UNITED STATES PATENTS rial. After the insulating material has solidified, the ex- 3.599.325 8/1971 Burr 1 29/597 cess parts of the wire are cut off to leave a stator hav- 3,548.123 12/1971) Allison ZOO/1 1 ing a plurality of equi-spaced radial contact studs and 3-539-854 11/1970 Futterer 9 a 310/233 the same number of parallel electrical contact mem- 3,529 348 9/1970 Kucharskin. 1. 29/597 b respectively connected thereto 3524.250 8/1970 Burr v 2 /597 v14711.1 x0 11/1969 Bang 200/1 1 D 4 Claims, 4 Drawing Figures PATENTED HARZB I874 SHEEI 1 BF 2 METHOD OF MAKING A ROTARY SWITCH STATOR FIELD OF. INVENTION The present invention relates to a method of producing a stator element for a miniature rotary switch, and the stator element so produced. A switch constructed using the design of the present invention is suitable for direct mounting on a standard predrilled printed circuit board.

DESCRIPTION OF THE PRIOR ART Known methods of producing rotary switch stators usually start with a metal sheet from which is stamped the conductor elements these individual elements being held together by part of the said sheet not required by the stator conductors in'their final form, this excess material being removed after the elements have been molded into the stator assembly. The molding forms a'hollow insulating body through which the stator contacts conduct electricity from external connections to the moving central assembly of the switch.

Such a construction has the disadvantage that the contact studs formed by the inner ends of the stator conductors are relatively-fragile and the contacts are subject to electrical losses.

An improvement to the above construction is described in my French Pat. No. 1,398,866 wherein the conductive stator elements are manufactured by preforming round wire to the shape of a'multi-point star closed on itself, which is incorporated and centred in the mold of the stator element. The reentrant sections of the star extending towards the centre of the assembly are trimmed to separate them and constitute the rounded contact studs and the conductive elements are rendered separate externally by cutting off the excess conductor.

The disclosure in my French Pat. No. 1,398,866 is an improvement in the previously known prior art in that it uses a round wire which can consist of either a solid precious metal or be plated with such a metal and has no surface roughness which might be conducive to electric breakdown and losses.

The disadvantage of the switch stator made in accordance with the previously known prior art is that the disposition of the connections external to the switch these being around the periphery of the stator, is not suitable for many applications.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotary switch stator element using round section electrical conductors which conductors are brought out of one flat external face of the stator molding in a manner suitable for their direct insertion in a standard predrilled printed circuit board.

According to the present invention there is provided a method of manufacturing a rotary switch stator including the steps of:

a. bending at least one wire to form a plurality of meander loops having arcuate portions at the ends interconnecting long rectilinear portions;

b. taking the meander loops at one end and arranging parts to form a plurality of rectilinear portions in equi-spaced relation in a circle and radially aligned with respect to the centre of the circle;

c. arranging the remaining parts of the meander loop in parallel arrangement whereby a number of intermediate connecting parts are provided between the radial parts and the parallel parts;

(I. holding said radial parts and those portions of said parallel parts adjacent said intermediate parts in fixed relation;

e. placing said intermediate parts in a molding zone;

f. pumping into said molding zone, electrically insulating material in liquid form; g. allowingsaid liquid to set within the molding zone;

h. removing the resulting cast stator element from said molding zone;

. cutting away the inner arcuate portions joining the radial portions so as to leave a plurality of equispaced contact studs; and

j. cutting away the excess parts of the parallel portions of the meander loops so as to leave a corresponding number of electrical contact members.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described in greater detail by way of example with reference to the accompanying drawings, wherein:

FIG. I is a plan view ofa round wire bent in a plane;

FIG. 2 shows two superposed wires one being of the form of FIG. 1, the other being a mirror image of the first;

FIG. 3 is a sectional view rated in a mold; and

FIG. 4 is a perspective view of a stator element produced in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the wire A is bent into the shape shown which shape comprises three bent loops 1, 2, 3, which are joined by the semi-circular rounded sec tions 4 at their outer ends, to form a hairpin-shaped element, so that, with the two ends 5 and 6 of the wire,

the four rectilinear portions 7 form six parallel rectilinear branches.

The central arms 2 are shaped such as to comprise two rectilinear sections 8 and 8a joined by a rounded section 9, the rectilinear sections being radial in relation to the centre 0 there being an angle 3 of between them.

The two external pairs of arms 1 and 3 are bent over at their inner ends towards the central arms 2 and each comprise two rectilinear radial sections 8 joined by the arcs 9, the said radial sections being at an angle of 60 to one another with two neighbouring rectilinear sections 8, belonging to two different loops, also having an angle of 60 between them.

Thus there is obtained around the centre 0 six rectilinear radial sections which are equi-angularly spaced and which, assuming the whole to be incorporated in a molded member B, can provide, after severing of the arcs 9 along the circle ll,six contact studs within the cavity of the molded member'B, which correspond to the six pins obtained after the severing of the two semi-circular sections 4. v

If only six conductor elements, each comprising one pin, one stud and the intermediate section embedded of the two wires incorpoin the material of the member B, are used, the two pairs of arms I and 3 may be positioned symmetrically about the central arms, which are also of symmetrical form. V

However, in the illustrated embodiment, the ends of the three pairs of arms incorporated in the molded member B are deformed to correspond to a rotation of all the elements 8 through relative to the axis XX in the plane of the member B and about the centre 0.

Thus, the rectilinear section 8a is at an angle a of exactly 15 with the said axis XX.

Hence by the superposition of two wires A and C which are both shaped as wire A of FIG. 1 but one of which is turned over in relation to the other, it is possi ble to obtain twelve radial sections 8 which are spaced apart by 30, and which correspond to twelve pins lying in two parallel planes.

Referring now to FIGS. 2 and 3, there is shown an example of a mold assembly which enables two flat wires shaped as above to be incorporated in a molded member.

The mold illustrated in FIG. 3 comprises a base 12, an intermediate section 13, a top section 14 and a central core 15, the

elements

12,13 and 14 being secured together by means of pins 29. Tile mold base 12 is provided with an injection orifice 25, and a central annular part 16 on the top of which there are cut 12 radial slots 17 of semi-cylindrical form, which are intended to receive the 12 radial sections 8 of the two bent wires A and C. In addition, the edge of the base 12 is formed with six rectilinear slots 18 running perpendicular to the said edge, which receive the

rectilinear sections

5, 6 and 7 of the wire A.

The intermediate section 13 is formed with six slots 19 in registration with the slots 18 in the face of the base 12, and six other slots 21 in the face directed towards the cover 14, which latter slots are interspaced, as seen in plan view, between the mentioned slots (18 and 19) and receive the

rectilinear sections

5, 6 and 7 of the wire C. The cover 14 is formed with six slots 22 opposite the slots 21 and a central bore 23 to enable thecore 15 to be slid in and out of the mold.

To produce a stator element, the components of the mold having been placed one above the other but spaced apart from one another, the wire A is first placed in one-half of the

slots

17 and 18. The section 13 is then lowered onto the base 12, and there is then placed on this section the wire C, still in the flat state, which is clamped parallel to the plane of the wire A by the cover 14 which is pressed against the section and the base.

Next, the core 15 is pushed into position and is prevented from rotating in relation to the remainder of the mold by suitable means (not shown).-The end of the core 15 has formed in it the radial slots 32 which match the slots 17. When it engages the rectilinear sections 8 of the wire C, the pairs of arms, 1, 2 and 3 of the said wire are bent downwards and the curved sections 26 and 27 (FIG. 2) of the wire are bent as illustrated in FIG. 3 within an annular cavity 28 bounded by the core 15 formed the inner wall and the

elements

12, 13 and 14 forming the outer wall.

Next, a suitable electrical insulating material in liquid or semi-liquid form is pumped into the annular cavity 28 through the injection orifice 25, said material then solidifying in the course of time. After the solidification of the insulating material injected into the cavity 28, the various wire sections 7 are permanently located in the positions illustrated in FIGS. 2 and 3.

It is to be noted that, by reason of the superimposition in different planes of the wires A and C, there is always a substantial thickness of insulating material between any two wires embedded in the molding.

Finally, the molding is released and trimmed and the rounded arcs 9 within the cavity 30 of the molded member B are cut off in a press, the outer arcs being similarly removed and the molded article shown in FIG. 4 is obtained. The twelve rectilinear sections 8 project radially into the cavity 30 and each of them is contiguous with one pin (5, 6 or 7), the parallel pins being disposed to form two sets of six equi-distant pins in two parallel planes. These pins are arranged in two rows which are staggered in relation to one another with a uniform square spacing of 2.5 mm, which is the standard spacing for weak-current printed circuit cards.

The radial sections 8 are advantageously turned down as shown or bent in a press so as to be spaced apart and more suitably shaped to enable a movable contact member to slide over them. If the

pins

5, 6, 7 are intended to have conductors fixed thereon by wrapping they may be of the length shown in the drawings. If the connecting conductors are soldered to these pins, they may be shortened and the wire may be bent to the length defined by the rounded portions 4a.

Finally, the cavity 30 may include a shoulder 31 forming a bearing for the rotor.

The invention is applicable to the production of miniature contactors, such as those used in the. complex electronic circuits produced on parallel spaced-apart cards, on which they are mounted circuits associated with electronic components.

What I claim and desire to secure by Letters Patent 1. A method of manufacturing a rotary switch stator including the steps of:

a. bending at least one wire to form a plurality of meander loops having arcuate portions at the ends interconnecting long -rectilinear portions;

d. holding said radial parts and those portions of said parallel parts adjacent said intermediate .parts in fixed relation;

e. placing said intermediate parts in a molding zone;

f. pumping into said molding zone, electrically insulating material in liquid form; g. allowing said liquid to set within the molding zone;

h. removing the resulting cast stator element from said molding zone;

' i. cutting away the inner arcuate portions joining the radial portions so as to leave a plurality of equi spaced contact studs; and

in two parallel planes whereby the resulting contact members after the molding and cutting operations are located in two parallel rows of contacts, the elements of one row being staggered in relation to those of the 1 other row.

3. The method according to claim 2, wherein there are 12 radial parts for forming l2 equispaced radial contact studs, and the contact elements are arranged in two rows of six.

4. The method accordingto claim 2, further comprising: compressing the radial parts of the two sets substantially in the same plane parallel to said parallel planes.

Claims

1. A method of manufacturing a rotary switch stator including the steps of: a. bending at least one wire to form a plurality of meander loops having arcuate portions at the ends interconnecting long rectilinear portions; b. taking the meander loops at one end and arranging parts to form a plurality of rectilinear portions in equi-spaced relation in a circle and radially aligned with respect to the centre of the circle; c. arranging the remaining parts of the meander loop in parallel arrangement whereby a number of intermediate connecting parts are provided between the radial parts and the parallel parts; d. holding said radial parts and those portions of said parallel parts adjacent said intermediate parts in fixed relation; e. placing said intermediate parts in a molding zone; f. pumping into said molding zone, electrically insulating material in liquid form; g. allowing said liquid to set within the molding zone; h. removing the resulting cast stator element from said molding zone; i. cutting away the inner arcuate portions joining the radial portions so as to leave a plurality of equi-spaced contact studs; and j. cutting away the excess parts of the parallel portions of the meander loops so as to leave a corresponding number of electrical contact members.

2. The method according to claim 1, including: forming a second set of meander loops of identical form to the first set; placing the radial parts of the second set in between the radial parts of the first set so that all the radial conductors are equi-spaced in the circle; and holding said parallel parts of the first and second sets in two parallel planes whereby the resulting contact members after the molding and cutting operations are located in two parallel rows of contacts, the elements of one row being staggered in relation to those of the other row.

3. The method according to claim 2, wherein there are 12 radial parts for forming 12 equispaced radial contact studs, and the contact elements are arranged in two rows of six.

4. The method according to claim 2, further comprising: compressing the radial parts of the two sets substantially in the same plane parallel to said parallel planes.