US3213211A

US3213211A - Multi-position wafer switch with fastening means and short-circuiting contact structure

Info

Publication number: US3213211A
Application number: US221096A
Authority: US
Inventors: Kenneth C Allison
Original assignee: CTS Corp
Current assignee: CTS Corp
Priority date: 1962-09-04
Filing date: 1962-09-04
Publication date: 1965-10-19
Anticipated expiration: 1982-10-19
Also published as: GB1062941A

Description

Oct. 19, 1965 K. c. ALLISON 3,213,211

MULTI-POSITION WAFER 5 CH H FASTENING MEANS AND SHORT-GIRCUIT CO CT STRUCTURE Filed Sept. 4, 1962 3 Sheets-Sheet l O HHHHHI 56 HHHIIHIIHHIIIH O II Q) 2 0 OO GO G O Q 0 ding} 2 llll O G 30 O O 28 Q G O IHH /6 20 O y 57 Q Q) /0 FIG. 2

INVENTOR KENNETH C. ALLISON ATTORNEY 0 FIG. I.

Oct. 19, 1965 K. c. ALLISON 3,2 211 MULTI- ION WAFER SWITCH WITH FASTENING MEANS AN ORT-CIRCUITING CONTACT STRUCTURE Filed Sept. 4, 196 3 Sheets-Sheet 2 INVENTOR KENNETH C. ALLISON FIG 6 BYflQW'WgM ATTORNEY Oct. 19, 1965 K c, ALLISON 3,213,211

MULTI-POSITION WAFER SWITCH WITH FASTENING MEANS AND SHORT-CIRCUITING CONTACT STRUCTURE Filed Sept. 4, 1962 3 Sheets-Sheet 3 INVENTOR KENNETH C. ALLISON BY gl 13. M

AT TOR NEY United States Patent MULTI-PGSITION WAFER SWITCH WITH FASTEN- ING MEANS AND SHURT-CIRCUITING CON- TACT STRUCTURE Kenneth C. Allison, Crystai Lake, IlL, assignor to CTS Corporation, Elkhart, Ind., a corporation of Indiana Filed Sept. 4, 1962, Ser. No. 221,096 Claims. (Cl. 200-11) This invention relates to multi-position electric switches generally, and in particular, to improving the means for anchoring the stationary and movable contacts to the bodies of insulating material which form the stator and rotor of the switch.

One persistent problem has always confronted rotary switch designershow to securely anchor the stationary contacts to the stator and the blade to the rotor in a manner that will not be prohibitively expensive but which will prevent the contacts from moving relative to the member to which they are attached, and which will not prevent or restrict the movements necessary to the operation of the switch.

The switch contact members are most commonly attached by eyelets or hollow rivets. This is the simplest and most economical method. Rivets, however, are unable to hold the contacts aligned properly. In other words, when the moving rotor blades engage the stationary contacts, they tend to rotate around the rivet in the same direction as the rotor blades are moving. Obviously, such movement should be prevented.

This is commonly done by having the lower half of the contact jaw extend into a slot formed in the stator body. This arrangement requires the spring arm of the lower contact jaw to be shorter than the spring arm of the upper jaw which combines with the resistance to movement offered by the slot to force the upper jaw to do most of the flexing necessary to accommodate the rotor blade. This shortens the life of the contact, causes uneven contact wear, and generally increases the torque necessary to move the rotor blade from position to position.

Accordingly, it is an object of this invention to provide means for attaching the contacts to a rotary wafer switch which will eliminate relative movement of the contacts with respect to the body of insulating material to which they are attached.

It is a further object of this invention to provide means for anchoring the movable contact blades carried by the rotor which will support the contacts at the maximum possible distance from the center of the rotor.

It is an additional feature of this invention to provide a contact for the stator which will resiliently engage the stator with sufficient force to prevent relative movement of the contact but which will not damage the stator.

It is also an object of this invention to provide a switch with symmetrically shaped stationary contacts attached to the switch stator so that both jaws are free to move equal distances.

It is an additional object and an important feature of the invention to provide a switch which is so designed that misalignment between the stationary contacts and the rotor blades is eliminated.

It is also an object of this invention to provide a 3,213,211 Patented Oct. 19, 1965 rotary wafer switch of generally simplified and improved design.

The invention comprises a stator and a rotor, each being a body of insulating material with attached electrically conductive contacts. The stator body is T- shaped in cross section, having a thick peripheral section and a relatively thin inner section. The inner section supports the rotor whereas the peripheral section supports the contacts which can be attached to both sides. The peripheral section also is provided with ribs or abutments between which the contacts are located. The contacts are provided with a curved section which engages the ribs or abutments at the outer periphery of the stator for aligning the contacts with respect to the ribs and for preventing rotation of the contacts around the attaching rivet. The contact jaws do not engage the ribs on the stator so both are free to flex equal amounts to accommodate the rotor blades.

The rotor is rotatably supported by the stator and comprises a body of insulating material with a plurality of metal fingers embedded therein. The fingers support a flat metal member from which the desired blading is formed. Being firmly embedded in the body of the rotor the blades are securely held against rotation with respect to the body of insulating material. The blades are also securely held against movement out of the plane of the stationary contacts since the rotor body supports the blade the maximum possible distance toward the stationary contacts.

Also since the rotor blading is formed after it is attached to the rotor, various individual blades are located on the rotor very accurately. In fact, the blades are located within the accuracy of the tooling which forms them. This system is obviously much superior to the heretofore used system of forming the rotor blades prior to their being attached to the rotor body. The rotor blades can now be very accurately positioned in both the horizontal and vertical planes and held in position throughout the life of the switch since no relative motion can occur between the rotor blades and the rotor body.

The invention will now be described in detail in connection with the accompanying drawings in which:

FIGURE 1 is a plan view of a rotary wafer switch constructed in accordance with this invention;

FIGURE 2 is a cross-sectional view of the switch of FIGURE 1 taken along line 2-2;

FIGURE 3 is an isometric view of a typical stationary contact showing how the section adjacent the rivet hole is curved;

FIGURE 4 is a sectional view illustrating the relationship of the curved section of the stationary contact and the stator prior to riveting;

FIGURE 5 illustrates the position of the curved section after the stationary contact is riveted to the stator;

FIGURE 6 is an enlarged top view of a stationary contact in position between two ribs;

FIGURE 7 is a portion of a metal strip which has had portions cut away preparatory to having the rotor body molded thereto;

FIGURE 8 shows the metal strip of FIGURE 7 after the molding operation; and

FIGURE 9 illustrates another method of anchoring the stationary contacts against rotation.

The switch consists of a stator section It) and a rotor section 12. The rotor section has an opening 13 to receive a flat sided shaft (not shown) by which rotation is imparted to the rotor.

The stator section comprises an annular body of insulating material with a plurality of contacts attached thereto. The annular body is T-shaped in cross-section having a relatively thick peripheral section 14 and .a relatively thin inner section 15. The inner section serves to insulate the contacts mounted on one side of the stator from those mounted on the other and to rota-tably support the rotor. Mounted on both sides of the relatively thick peripheral section 14 of the stator is a plurality of contacts indicated generally by the number 1 1 which are identical except for their length. For example, the contact 16 extends inwardly toward the rotor further than does the contact 17 which is a well known expedient to vary the switch circuitry.

The contacts 11 are attached to the stator body by means of hollow rivets or eyelets 18 which extend through openings 1 9 in the contact and openings 20 in the stator body as illustrated in FIGURE 2. Each contact is located between two ribs or abutments .22, a plurality of which are provided on both sides of the thick peripheral section of the stator body. Each rib or abutment is provided with a wedge-shaped back section 125 so that the distance between them is less .at the outer periphery than it is at the inner edge of the section 14. In the switch illustrated, these ribs or abutments are equally spaced and arranged to extend radially from the center of the switch. This is not necessary for the practice of the invention as the ribs could extend across the stator at any angle commensurate with good switch design.

The openings 20 which are provided in the stator for the eyelets :18 are located equidistant between each pair of ribs -22 so that a contact can be mounted between any pair of ribs on either side of the stator. In the stator illustrated in the drawings, the width of the ribs is such that contacts cannot be placed between adjacent pairs of ribs on the same side of the stator without reducing the width of the contact jaws. Generally, it is better to have contact jaws as wide as possible to maintain the contact pressure as large as possible. Rather than reduce the width of the jaws the ribs 22 are made as narrow as possible to provide as many locations for contacts as can be conveniently arranged on the stator. On the switch stator illustrated on the drawings, the ribs are spaced so that there are 22 locations for contacts on each side of the stator. Twenty-four spaces would be available except that some space must be provided for mounting

holes

23 and 24.

Since contacts cannot be placed in adjacent spaces as discussed above, the maximum number of contacts which can be attached is 12 on one side and 10 on the other for a total of 22. If it is desired to electrically connect contacts on opposite sides of the stator, the number will vary accordingly. Contacts on opposite sides of the stator can be electrically connected by means of the eyelet or rivet which is used to attach both contacts to the stator.

The contacts 1 1 are conventionally shaped. Each is formed from a single strip of metal bent back on itself. Each has

contact jaws

28 and 29, opening '19 to receive the mounting eyelet or rivet, and the opening 30 through which a wire lead can be passed when the switch is connected in an electric circuit. The contact is shown in FIGURE 3 as it appears before being attached to the stator. 'When attached the two halves are forced together as shown in FIGURE 2. This forces the

contact jaws

28 and 29 into engagement so that they will tightly grip the rotor blade 31 for good electrical contact.

Usually the portion of the contacts from the contact jaws out to the terminal end are flattened when they are attached to the stator. The stationary contacts of this invention, however, are constructed so that the solder terminal section will not be completely flattened.

As shown in FIGURES 3, 4, and 5, each half of the contact has oppositely

curved sections

44 and 45 located just back of the rivet hole 19. The width of the contact at this point is such that when placed in position between the ribs, there will be ample clearance. This allows the contacts to be positioned easily during assembly. When the contact is riveted to the stator body however, the width of the curved sections will increase as they are flattened by the riveting operation until they engage the ribs on each side. Actually only the section which happens to be next to the stator will engage the ribs since it will :be flattened more than the other. When this section engages the ribs, (section 45 as shown in FIGURE 5) the contact will be forced into alignment with the ribs. In other words if the contact is out of alignment when initially installed which is generally the case, one side of the curved section will engage the rib and rotate the contact into position during the riveting operation since it will inherently seek to exert an equal amount of force on each rib. These curved sections then combine with the ribs to provide an automatic method of aligning the contacts during assembly. In this way, the contacts can be dropped into position without regard to their alignment which greatly facilitates the mass production of these stators.

After the curved section has engaged both ribs thus forcing the contact into alignment, it will begin to resist further flattening since to do so it must cut into the ribs. The width ot the contact is not such that even if it were forced completely flat it would out very deep into the ribs, however, the curved sections are spaced from the rivet far enough to allow some curvature to remain after the riveting operation is completed. This allows the curved section to engage the ribs resiliently so that only a given amount of force will be exerted on the ribs after which the curved section will simply be flattened no further. This is an important feature since there is a danger that the contact could exert enough force to shear the ribs off the stator body if they were completely flattened particularly if a structurally weak or brittle plastic is used to form the body, as is sometimes the case.

Another feature of this invention is the use of two oppositely

curved surfaces

44 and 45 making line contact with each other. Since the force flattening these sections is transmitted to the bottom section through the upper section the fact that the two sections make line contact allows the bottom section to freely adjust to its proper position between the ribs 22 without having to overcome izny extraneous horizontal components of the flattening orce.

Once in position between the ribs, the contact 11 is accurately aligned with respect to the stator and securely held against movement by the rivet or eyelet 18 and the curved section 45 in engagement with the ribs 22 on each side of the contact. It is advantageous to have the curved section as far away from the rivet as possible to increase the moment arm resisting rotation and to get the best possible spring action from the

curved sections

44 and 45. It is also important that the means used to resist rotation of the contact be located on the opposite side of the contact from the contact jaws. This leaves the contact jaws completely free to flex and allows them to be identically shaped so that they will flex equal amounts.

If the stator is made from a fairly soft material and the abutments or ribs are not needed for locating or insulating purposes, the contacts can be anchored against rotation in the manner illustrated in FIGURE 9. No change need be made in the configuration of the contacts. The

curved sections

44 and 45 are so curved that they inherently provide the

sharp edges

46 and 47. These edges are positioned so that when the contact is attached the downward force of the riveting operation will tend to force these edges into the body of the stator. If the stator is made from a relatively soft material, they will 5 be embedded in the stator to such an extent that they will effectively hold the contact against rotation around the unit.

Here, as is the case when the contact is located between ribs, the curved sections are not flattened by the riveting operation. This allows these sections to resiliently hold the

edges

46 and 47 in engagement with the stator body. This resilient force also continuously exerts an upward force on the rivet thus preventing any looseness from developing between the contact and the rivet and the

edges

46 and 47 and the stator.

The rotor for the switch comprises a body of insulating material which supports one or more flat electrically conductive blades. The switch illustrated has stationary contacts on both sides of the stator so that rotor must also be equipped with blades on each side of the stator.

The rotor itself is made in two

sections

32 and 33. The two sections are identical and are combined to form the rotor by simply turning one section over so that the top side of each is facing outwardly from the switch. The blading of each section is different, of course, since the contacts in one side must be at least 15 in advance of the other. It is the configuration of the body of insulation which is the same. Each rotor section is formed by molding a body of insulating material around a plurality of fingers formed in a metal strip. FIGURE 7 illustrates the metal strip preparatory to having the insulating material molded thereto. A group of perforations generally indicated by the

numbers

51, 52, 53 and 54 are formed in a circular pattern in the strip. These perforations provide fingers which are embedded in the bodies of insulating material. These fingers then support the blading which is formed from the metal strip adjacent the periphery of the body of insulating material. The fingers are embedded by molding the body of insulating around them. This is done before the blading is formed. The metal strip with the rotor body molded thereon is shown in FIGURE 8. The dotted lines indicate a typical rotor blade pattern. In fact it is the same pattern as that shown in the switch of FIGURE 1.

This method of forming the rotor blading provides great flexibility in the manufacture of rotary switches. Simply by arranging the cutting dies properly practically any desired blading arrangement can be accurately and economically mass produced. In addition, the blades are securely held by the rotor body the maximum possible distance from the center of the rotor. This allows thinner more flexible metal to be used for the blading which reduces the distance the contact jaws on the stationary contacts are flexed, greatly lengthening their life.

This type rotor also insures that the blading is all in the same horizontal plane which eliminates variation in contact pressure. This also lengthens the life of the switch and in addition produces a better performing switch.

The rotor is assembled in the manner shown in FIG- URE 2 with the

sections

32 and 33 on opposite sides of the thin inner section 15 of the stator. Each section is provided with a groove 55 which engages the section 15 and acts as the bearing for the rotor. The two sections are held together on the stator by rivets 56 and 57 which extend through

openings

58 and 59 provided in both sections.

If a single sided rotary switch is desired, no change in the basic structure would be required. Stationary contacts would be placed on only one side of the stator, of course, and the rotor would consist of the same two sections except that one section would have no metal inserts to provide blading.

While there has been illustrated and described what is at present considered to be a preferred embodiment of the present invention and a single modification thereof, it will be appreciated that numerous changes and modifications are likely to occur to those skilled in the art,

6 and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.

The invention claimed is:

1. In a multi-position electric switch, the combination of a first and second cooperating relatively movable contact carriers of insulating material, a plurality of contact members arranged in a row and fixedly secured to opposite sides of the first contact carrier; a pair of symmetrical contact jaws integrally secured to each of the contact members and extending toward the outer edge of the second contact carrier; the second contact carrier comprising a pair of insulating members disposed on opposite sides of the first contact carrier; a groove provided in the second contact carrier receiving and guiding a portion of the first contact carrier cooperating therewith upon relative movement between the first and second contact carriers; a pair of common contacts, each of the insulating members being molded to one of the common contacts, each of the common contacts lying in a plane interposed between the contact jaws of the contact members associated therewith and moving relative to the contact members in a path to be selectively engageable with the contact jaws as the switch is actuated to connect electrically the individual contact members with the common contacts.

2. In a multi-position electric switch, the combination of a first and second cooperating relatively movable contact carriers of insulating material; a plurality of spaced ribs integrally secured to the first contact carrier along the outer edge thereof; a plurality of contact members arranged in a row and disposed between the spaced ribs, each of the contact members being provided with a laterally disposed curved portion embedded in the portion of the rib adjacent to the outer edge of the first contact carrier, the portion of each of the ribs adjacent to the outer edge of the first carrier being wedge-shaped so as to provide a slot having a smaller width at the outer periphery of the first carrier and a larger width at the other end of the slot to position the contact members between the ribs; a pair of symmetrical jaws integrally secured to each of the contact members; a common contact; and supporting means integral with the common contact fixedly secured to the second contact carrier, the common contact lying in a plane interposed between each of the pair of symmetrical jaws and moving relative to the first carrier in a path to be selectively engageable with the symmetrical jaws of each of the contact members as the switch is actuated to connect the individual contact members electrically with the common contact.

3. In a multi-position electric switch, the combination of a first and second cooperating relatively movable contact carriers of insulating material; a common contact; supporting means integral with the common contact, the second contact carrier being molded to the supporting means, a plurality of contact members arranged in a row and fixedly secured to one side along the outer edge of the first contact carrier, each of the contact members being provided with a laterally disposed curved portion, the edges of the curved portion being embedded in the first contact carrier to prevent movement of the contact member with respect to the first contact carrier; a pair of symmetrical jaws integrally secured to each of the contact members; and a rivet fixedly securing each of the contact members to the first contact carrier, the rivet being received by an opening provided in the contact member intermediate the symmetrical jaws and the curved portion to permit free movement of the symmetrical jaws upon selective engagement with the common contact, the common contact lying in a plane interposed between each of the pair of symmetrical jaws and moving relative to the first carrier in a path to be selectively engageable with the symmetrical jaws of each of the contact members as the switch is actuated to con- 7 nect the individual contact members electrically with the common contact.

4. In a multi-position electric switch, the combination of a first and second cooperating relatively movable contact carriers of insulating material; a plurality of contact members arranged in a row and fixedly secured to one side along the outer edge of the first contact carrier, each of the contact members being provided with a laterally disposed curved portion, the edges of the curved portion being embedded in the first contact carrier to prevent movement of the contact member with respect to the first contact carrier; a pair of symmetrical jaws integrally secured to each of the contact members; a common contact; and supporting means integral with the common contact, the second contact carrier being molded to the supporting means, the common contact lying in a plane interposed between each of the pair of symmetrical jaws and moving relative to the first carrier in a path to be selectively engageable with the symmetrical jaws of each of the contact members as the switch is actuated to connect the individual contact members electrically with the common contact.

5. A multi-position electric switch comprising:

a stator of insulating material having a thick outer peripheral section and a thin inner peripheral section;

a plurality of abutments on the outer peripheral section;

a plurality of contacts, each contact being located between two abutments;

a rivet attaching each of the contacts to the outer peripheral section of the stator;

a curved section on each contact adjacent the outer periphery of the stator resiliently engaging the abutments on each side of the contact to align the contact and resist rotation of the contact around the rivet; and

a rotor rotatably supported by the stator, comprising:

body of insulating material; and a plurality of metal inserts embedded in the body and extending outwardly therefrom to engage the contacts attached to the stator.

6. A multi-position electric switch comprising:

an annular body of insulating material having a relatively thick outer peripheral section and a substantially thin inner peripheral section;

a plurality of radially extending, equally spaced ribs on at least one side of the thick outer peripheral section;

a plurality of symmetrical metallic contact members attached to the annular body with each contact member being located between a pair of the ribs;

means attaching the contact members to the annular body;

each of the metallic contact members having a curved section located adjacent the outer periphery of the annular body, said curved section having a width initially less than the space between adjacent ribs but a width greater than the distance between the ribs when flattened, so that the edges of the curved section will be forced into engagement with the ribs when the contact member is attached to the stator; and

a rotor rotatably supported by the substantially thin inner peripheral section of the annular body comprising a body of insulating material having a metal contact embedded therein.

7. A multi-position electric switch comprising an annular body of insulating material having a relatively thick outer peripheral section and a thin inner peripheral portion;

a plurality of abutments on the thick outer peripheral section;

a plurality of contact members with each member being located between a pair of abutments;

means attaching the contact members to the stator;

each contact member being characterized by two oppositely curved sections extending transverse the contact member with one curved section engaging the abutment on each side of the contact member to resist rotation of the contact member around the attaching means; and a contact blade engageable with the contact members.

8. A stator for a multi-position electric switch comprising:

a body of insulating material equipped with a plurality of abutments, said abutments being so constructed and arranged that the distance between the abutments is a minimum along the outer periphery of the body;

a plurality of symmetrical contacts attached to the body with each contact being located between two abutments;

openings in each of the contacts and in the body between each pair of abutments where a contact is located;

holding means extending through the openings in the contacts and the body of insulating material securely attaching the contacts to the body;

said contacts being characterized by the fact that they are provided with two oppositely curved transverse sections adjacent the outer periphery of the body, the curved sections initially having a width less than the minimum distance between the abutments but greater than the minimum distance when they are fiat, so that when attached to the body by the holding means, the curved transversed sections will be flattened to the extent that at least one curved transversed section will resiliently engage the abutments on each side to thereby accurately align the contact with respect to the abutments and to resist the rotation of the contact around the holding means.

9. A multi-position electric switch comprising, in combination, a stator and a rotor;

said stator comprising a body of insulating material having a relatively thin inner section having a central opening therein, a relatively thick peripheral section, and a plurality of stationary contacts attached to the peripheral section;

said rotor comprising two annular bodies of insulating material; a metal member embedded in one annular body and extending outwardly from the peripheral edge thereof in the plane of the stationary contacts; each of the annular bodies having a diameter larger than the central opening in the stator and an end section of reduced diameter which extends into the central opening in the stator, and means attaching the two annular bodies together so that both annular bodies will be rotatably supported by the inner section of the stator.

lit). A multi-position electric switch comprising:

an annular stator body of non-conductive material having a relatively thick outer peripheral section and a relatively thin inner peripheral section;

a plurality of U-shaped metallic contact members;

means attaching the U-shaped metallic contact members to the thick outer outer peripheral section of the annular stator body;

each of the metallic contact members having an initially curved section located adjacent the outer periphery of the stator body, said curved section being curved to the extent that only the edges of the curved section engage the stator body so that when the contact members are attached to the stator body the curved section will be partially flattened and the edges will be embedded in the stator body;

a rotor rotatably supported by the stator body;

said rotor comprising two sections rotatably mounted on opposite sides of the relatively thin inner peripheral section; each of the sections of the rotor being provided with a circumferential groove engaging the 2,594,111 4/52 Albrecht 2001 67 X edge of the thin inner peripheral section of the all- 2,631,211 3/53 Klay. nular stator body; and 2,828,393 3/58 Wingard 20011 a metal contact molded in the rotor and arranged to 2 900 462 8/59 Th t 1 200 11 engage the contact members on the stator body. 5 2,949,511 8/60 Glueckstein et 1 20 11 References Cited by the Examiner x lm lson UNITED STATES PATENTS 2,989,710 6/61 Gelzer et a1. 2,210,842 8/40 Schellenger 200-11 2,554,724 5/51 Williams 200-11 10 BERNARD A. GILHEANY, Primary Examiner.

Claims

5. A MULTI-POSITION ELECTRIC SWITCH COMPRISING: A STATOR OF INSULATING MATERIAL HAVING A THICK OUTER PERIPHERAL SECTION AND A THIN INNER PERIPHERAL SECTION; A PLURALITY OF ABUTMENTS ON THE OUTER PERIPHERAL SECTION; A PLURALITY OF CONTACTS, EACH CONTACT BEING LOCATED BETWEEN TWO ABUTMENTS; A RIVET ATTACHING EACH OF THE CONTACTS TO THE OUTER PERIPHERAL SECTION OF THE STATOR; A CURVED SECTION ON EACH CONTACT ADJACENT THE OUTER PERIPHERY OF THE STATOR RESILIENTLY ENGAGING THE ABUT-