US3317688A

US3317688A - Snap-action switch

Info

Publication number: US3317688A
Application number: US443304A
Authority: US
Inventors: Walter L Cherry; Fred N Anderson
Original assignee: Cherry Electrical Products Corp
Current assignee: Cherry Corp
Priority date: 1965-03-29
Filing date: 1965-03-29
Publication date: 1967-05-02
Anticipated expiration: 1984-05-02

Description

y 2, 1957 w. L. CHERRY ETAL 3,317,688

SNAP-ACTION SWITCH 2 Sheets-Sheet 1 Filed March 29, 1965 nited States Patent ()fiice 3,317,688 Patented May 2, 1967 3,317,688 SNAP-ACTION SWITCH Walter L. Cherry and Fred N. Anderson, Highland Park,

lllL, assignors to Cherry Electrical Products Corporation, Highland Park, 11]., a corporation of Illinois Filed Mar. 29, 1965, Ser. No. 443,304 7 Claims. (Cl. 200-67) This invention relates to a new and useful improvement in an electrical switch and more particularly to a snap-action switch which is generally, though not necessarily, incorporated in coin operated devices in which device the switch is actuated by the weight of the coin.

A principal object of our invention is in the provision in a snap-action switch of this character of a means for pre-assembling a rotor type switch actuator. Such means includes a preformed rotor stern having an actuator cam surface at one end thereof insertable into a correspondingly formed bearing housing provided as an integral part of the switch casing for correctly positioning and retaining the rotor actuator in an operative position with respect to the other movable components of the switch.

A further object of our invention is to provide in a snap-action switch of this character a means whereby certain movable components of the switch may be incorporated in a sub-assembly which readily facilitates the prefabrication of the complete switch unit.

Another important object of our invention is in the provision in a switch of this character of a housing which provides a resealable access opening in the cover thereof through which actuating adjustments of certain of the switch components may be achieved subsequent to their assembling and placement within the sealed switch housing.

Yet another object of our invention is in the provision in a switch of this character of an arrangement of parts so interrelated and interconnected that their assembly requires but a minimum amount of time and effort materially reducing the cost of production.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to 'be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

FIG. 1 is a perspective view of the back case of our improved switch showing the rotor actuator in an exploded relation with respect thereto;

FIG. 2 is a fragmentary perspective view showing the final assembled condition of the rotor actuator onto the back casing;

FIG. 3 is a perspective view of the back casing and switching components in an exploded relation;

FIG. 4 is a side elevational view of the switch when the cover is removed showing the switch components in their normal position;

FIG. 5 is a side elevational view similar to FIG. 4 but showing the switch components in an actuated position;

FIG. 6 is a side elevational view of the switch housing in its semi-sealed form;

FIG. 7 is a side elevational view of the inner wall of the switch cover;

FIG. 8 is a perspective view of the fully assembled switch;

FIG. 9 is a perspective view of the snap-in closure for the access window formed in our switch housing;

FIG. 10 is a perspective view of the rotor actuator.

Referring more particularly to the drawings and specifically FIG. 8, we show a completely assembled switch 10 which includes a hollow back casing 11, and a complementary hollow cover 12.

As viewed in FIG. 1, the back casing 11 has formed on its exterior rear wall 13 a laterally projecting bearing 14 which bearing 14 extends through the rear wall 13 of the casing 11 and into the internal hollow cavity provided by such casing. The bearing 14 is provided with a longitudinally extending opening 15 that includes a preformed keyway 16.

The bearing 14 is adapted to receive the elongated stem 17 of a rotor actuator 18. This rotor actuator 18 comprises an integral unit including a semi-circular retaining plate 19 which has extending laterally from one side a reduced stem 20 and a slotted retaining head 21 extending laterally from the opposite side thereof. From the flat edge of the semi-circular plate 19 there projects a lug 22 which in the final assembly of the rotor actuator 18 into the bearing 14 will be bent in the direction of the rear wall 13 in a substantially parallel plane with respect to the stem 17 as seen in FIG. 2.

Integrally molded on the reduced stem 20 is a sleeve 23 and an actuator cam head 24. This cam head 24 provides a key which, together with the cam head, is of a size greater than the diameter of the opening 15 formed in the bearing 14, with the key corresponding to the configuration of the keyway 16 formed in the bearing 14, so that when the head 24 is aligned with the opening 15 and keyway 16, the cam head 24 may be projected through the opening 15 and keyway 16 into the cavity within the casing 11.

The elongated stem 17 and sleeve 23 of the rotor actur ator 18 will be disposed in the opening 15 and rotatable therethrough. When the rotor actuator 18 is thus journalled through the bearing 14, the cam head 24 and key thereof will be disposed within the interior hollow cavity provided by the casing 11, while the semi-circular retaining plate 19 will be in facial abutment with the exposed surface of the bearing 14 exteriorly of the casing 11. In such position, the assembler of the switch unit will then partially rotate the rotor actuator 18 to radially displace the key of the cam head 24 out of alignment with the keyway 16 so that the key and cam head 24 will lie in facial abutment with the inner wall surface of the hearing 14. The ing 22 provided by the semi-circular retaining plate 19 will be forcibly bent so as to project between two spaced apart studs 25 formed integrally on the back wall 13 of the casing 11, as seen in FIG. 2. These stop studs 25 are so positioned relative to the keyway 16 that they will permit a limited rotation of the cam head 24 within the cavity formed in the casing 11, while at the same time preventing sufficient rotation to realign the head 24 with the keyway 16, preventing lateral movement of the cam head 24 out of the cavity formed in the casing 11. By this arrangement the rotor actuator 18 is specifically positioned relative to the remaining switch components as hereinafter described.

As shown in FIG. 3, the hollow back casing 11 has its lower wall 26 formed to provide a plurality of parallelly extending

slots

27, 28, and 29, each of which provide open communication with the cavity within the casing 11. Slot 27 is adapted to receive the fixed terminal 30 while the slot 28 receives the complementary fixed terminal 31, and the slot 29 will receive the combination terminal and pivot bracket 32.

The terminal 30 is so formed as to provide an angled end portion which constitutes a contact plate 33 with such plate being of a width so as to provide laterally extending shoulders 34 adapted to be received in horizontally aligned

recesses

35 and 36 formed in the confronting inner wall surface of the casing 11 and cover 12.

The terminal 31 is likewise provided with a contact plate 37 which provides opposite laterally extending side shoulders 38 which are adapted to be received in

recesses

39 and 40 formed in the inner wall surface of the casing 11 and cover 12. The contact plate 37 of the terminal 31 is supported by a vertically extending side leg member 41 which by its construction provides a passage 41' which extends between the contact plate 37 and the major body portion of the terminal 31. The purpose of the passage 41' will be hereinafter made apparent.

By the above described arrangement, the

terminals

30 and 31 are specifically and fixedly positioned within the switch housing relative to each other and the remaining components of the switch.

The combination terminal and pivot bracket 32 is formed so as to provide a terminal leg 42 which is received in the slot 29 formed in the lower wall 26 of the case 11 as viewed in FIGS. 3, 4, and 5. This terminal leg 42 terminates at its upper end into a horizontally extending fiat plate 43 which plate is turn supports a pair of vertically extending spaced apart pivot post's 44. These pivot posts 44 have their upper ends connected together by a crossbar 45 forming therebetween a passage 46. When the terminal and pivot bracket 32 is mounted in the casing 11, the passage 46 thereof will be in horizontal alignment with the passage 41 provided by the terminal 31 as shown in FIGS. 4 and 5.

The opposite outer edges of the pivot posts 44 are notched as at 47 so as to provide a point of pivotal connection thereto for the ends of corresponding legs 48 of a substantially U-shaped movable switch blade 49.

As seen in FIGS. 3, 4, and 5, one of the legs 48 of the movable switch blade 49 carries a contact point 50 which is adapted to be moved between

contacts

51 and 52 carried by the

contact plates

33 and 37 of the

fixed terminals

30 and 31 respectively. The movable switch blade 49 is yieldably connected to the pivot posts 44 by means of a spring 53. The spring 53 has one end connected to the medial portion 54 of the switch blade 49 and its opposite end 53' connected to the pivot bracket 32 by means of a hook end which engages into an aperture 54 formed in the line of junction between the terminal leg 42 and the flat plate 43 of the pivot bracket 32. In this position, the movable components comprise a sub-assembly and, as such, may be conveniently mounted within the cavity formed by the casing 11 prior to the final assembly of the switch unit.

After the

fixed terminals

30 and 31, as well as the pivot bracket 32 have been mounted into the casing 11, an actuating lever 55 is placed Within the cavity provided by such casing 11.

As shown in FIGS. 3, 4, and 5, one side wall 56 of the casing 11 has its inner wall surface preformed to provide a pivot seat 57. The actuating lever 55 has one end 58 thereof angled out of the normal plane of such lever 55 and formed to provide laterally extending arms 59 which at their outer ends provide bearing points 59'. These bearing points 59' are adapted to pivotally sit into the seat 57 provided by the side wall 56 of the casing 11. The opposite end of the actuating lever 55 is bent substantially at right angles to provide an angled end portion 60. This angled end portion 60 is provided with an opening 61, which when the actuating lever 55 is operatively connected to the remaining components of the switch, will receive and hold the hooked end 53' of the spring 53.

From the foregoing description, it is apparent that we have assembled into the casing 11 the sub-assembly consisting of the rotor actuator 18, as well as the subassembly comprising the terminal and pivot bracket 32 and movable switch blade 49. The actuating lever 55 has been pivotally mounted within the casing 11 by having one end thereof pivotally engaged in the seat 57 provided by the side wall 56 of the casing 11, and its medial portion supported upon the cam head 24 of the rotor actuator 18 as seen in FIGS. 4 and 5.

The final assembly of the switch components now requires that the hook end 53' of the spring 53 be connected 4 to the angled end 60 of the actuating lever 55. This is accomplished in the following manner:

When all of the foregoing described components of the snap-action mechanism employed in the switch are housed within the cavity provided by the casing 11, the assembler thereof, with the use of a suitable tool may reach in through an opening 62 formed in the side wall 63 of the casing 11 and remove the hook end 53 of the spring 53 from its engagement in the opening 54 formed in the terminal pivot bracket 32 and reconnect the spring 53 to the actuating lever 55 by hooking the end 53' of such spring 53 into the opening 61' formed in the angled end portion 60 of the actuating lever 55. In this final assembled condition, the components of the switch will be in their normal or unactuated condition, as shown in FIG. 4. The cover 12 may be then placed upon the casing 11 and by the use of suitable connecting means such as rivets projected through openings 61, and the like, connected thereto. As seen in FIG. 8, the cover 12 provides a laterally extending end wall portion 63' which, when the cover 12 is mounted on the casing 11, will close end opening 62 formed in the end wall 63 of the casing 11.

In the past, it has been found that during this procedure of securing the cover to the casing there are created certain stresses and strains which cause non-alignment of certain of the switch components which affect the operating characteristics thereof.

Prior switches of the type herein described, required the adjustment of juxtapositioning three elements, to wit: the two contact brackets and the angular location of the actuator rotor. Thus many times an assembler will find it necessary to chase one adjustment after another, increasing production time and cost.

To overcome this serious defect, we have provided in the cover 12 an enlarged circular access window 64. As shown in FIG. 6, this access window 64 permits the assembler to view the combination terminal and pivot bracket 32 after final assembly of the switch. As the operation of the snap action mechanism of the switch depends upon the proper geometry of the components of the switch, such for example, the relationship of the

contacts

51 and 52 carried by the fixed

terminals

30 and 31; the relationship of these contacts with the pivot posts 44; and the relationship of the switch blade 49, spring 53 and rotor actuator head 24; it is readily apparent that adjustment between all of these related components may be achieved through the single bending adjustment of the pivot posts 44. Thus, if the assembler finds that the snap action mechanism is not functioning under the prescribed operating force or that the overcentering line between the components is distorted so that there is a malfunction of such switch components the assembler may, through the use of a suitable tool inserted into the access Window 64, re-align the pivot posts 44 to correctly relate the switch components relative to each other. After such an adjustment, a seal 65 is adapted to be snapped into and securely closes the access Window 64.

As shown in FIG. 9, the cover 65 includes a plurality of equally spaced spring fingers 66 which are adapted to be frictionally pressed beyond a raised shoulder 67 formed about the peripheral access window 64.

The cover 65 provides a laterally extending positioning lug 68 which is adapted to be placed in registration with a notched-out portion 69 formed in such shoulder 67 so that the proper alignment of the cover 65 with respect to the access window 64 may be obtained.

Attention is brought to the fact that the connecting ends of the

terminals

30 and 31 as well as the connecting end of the combination terminal and pivot bracket 32 are twisted through a angle with respect to the major vertical plane of the respective terminals and brackets.

By this configuration, we permit easy access to such connecting ends of the terminal and bracket as well as strengthening the same to prevent accidental breakage or displacement thereof relative to each other and to the switch housing 10.

A suitable actuator (not shown) may be connected to the slotted head- 21 to the rotor actuator 18. When the same is caused to be moved, a limited rotation of the rotor actuator 18 is effected. By this limited rotation, the cam head 24 within the cavity of the housing is caused to be rotated into the position shown in FIG. 5, wherein it will effect pivotal movement of the actuating lever 55 through a vertical plane. This movement of the actuating lever will cause a resulting re-location of the horizontal plane of the spring 53 which will eifect the overcentering geometry of the switch components. This movement of the spring 53 will effect pivotal action of the switch blade 49 with a snap action into the position shown in FIG. 5, wherein the contact 50 of the switch blade 49 is moved out of engagement with the contact 51 of the terminal 30 and into Contact with the contact 52 of the terminal 31. After the actuating force has been removed,

the rotor actuator 18 will assume its normal position as shown in FIG. 4, and the switch components will return to their normal inoperative position as shown therein.

While we have illustrated and described the preferred form of construction for carrying our invention into effect, this is capable of variation and modification without departing from the spirit of the invention. We, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of such variations and modifications as come within the scope of the appended claims.

Having thus described our invention, what we claim as new and desire to protect by Letter Patent is:

1. A snap action switch having a normally open sided housing and cover therefor providing an interior cavity in which is positioned a snap acting switch mechanism including,

(a) a movable blade, a pivot bracket within said cavity for pivotal supporting one end of said blade, an actuating lever having one end pivotally connected to said housing and its opposite end connected by a spring to the other end of said blade and adapted to move said other end of said blade relative to said pivot bracket,

(b) a bearing member extending through said housing and having an opening extending longitudinally therethrough at a substantial right angle to said opposite end of said actuating lever,

(c) a keyway formed in said bearing member and in open communication with said opening formed therethrough,

(d) a rotor actuator journaled in said opening formed in said bearing member and providing at one end a cam head and key member pivotally supporting said opposite end of said actuating lever,

(c) said rotor actuator carrying a circular retaining plate exteriorly of said housing and in facial relation to the exposed end of said bearing member,

(f) said cam head and key member identical in configuration to said opening and said keyway formed in said bearing member and projected therethrough into said cavity of said housing with said key radially displaced with respect to said keyway to prevent longitudinal movement of said cam head through said opening in said bearing member and out of contact with said actuating lever,

(g) and means provided by said housing exteriorly of said cavity and adjacent to said bearing member cooperating with said retaining plate to limit rotation of said rotor actuator to pivoting of said actuating lever to actuate the snap acting mechanism and to prevent horizontal alignment of said key with said keyway and longitudinal movement of said cam head through said opening in said bearing member out of said cavity and out of contact with said actuating lever of said snap acting switch mechanism.

2. A snap action switch as defined by claim 1 wherein said means provided by said housing exteriorly of said cavity and adjacent to said bearing member that co operates with said retaining plate comprises a pair of spaced apart lugs carried by the rear wall of said housing in spaced relation to the exposed end of said bearing member.

3. A snap action switch of claim 1 further defined by having said cover providing a window opening formed therein out of horizontal alignment with said opening in said bearing member and positioned to provide access to the pivot bracket of the snap acting switch mecha nism within said cavity after the normally opened side of said housing is closed by said cover, and a removable lid for said window opening.

4. A snap action switch of claim 2 further defined by having said cover providing a window opening formed therein out of horizontal alignment with said opening in said bearing member and positioned to provide access to the pivot bracket of the snap acting switch mechanism within said cavity after the normally opened side of said housing is closed by said cover, and a removable lid for said window opening.

5. A snap action switch as defined by claim 1 wherein said rotor actuator includes an elongated stem of a length and diameter equal to said opening formed in said bearing member, said cam head and key member carried on one end of the stem within said cavity and in facial relation to the inner end of said bearing member and having a diameter greater than said stern, said retaining plate mounted on the other end of said stem in facial relation to said bearing member and having a diameter greater than the stem and said opening formed in said bearing member.

6. A snap action switch as defined by claim 5 wherein said means provided by said housing exteriorly of said cavity and adjacent to said bearing member that cooperates with said retaining plate comprises a pair of spaced apart lugs carried by the rear Wall of said housing in spaced relation to said bearing member.

7. A snap action switch of claim 5 further defined by having said cover providing a window opening formed therein out of horizontal alignment with said opening in said bearing member and positioned to provide access to the pivot bracket of the snap acting switch mechanism within said cavity after the normally opened side of said housing is closed by said cover, and a removable lid for said window opening.

References Cited by the Examiner UNITED STATES PATENTS 2,735,918 2/1956 Dan. 2,747,054 5/1956 Valverde 200138 2,805,299 9/ 1957 Cherry 200 ROBERT K. SCI-LAEFER, Primary Examiner.

D. SMITH, JR., Assistant Examiner.

Claims

1. A SNAP ACTION SWITCH HAVING A NORMALLY OPEN SIDED HOUSING AND COVER THEREFOR PROVIDING AN INTERIOR CAVITY IN WHICH IS POSITIONED A SNAP ACTING SWITCH MECHANISM INCLUDING, (A) A MOVABLE BLADE, A PIVOT BRACKET WITHIN SAID CAVITY FOR PIVOTAL SUPPORTING ONE END OF SAID BLADE, AN ACTUATING LEVER HAVING ONE END PIVOTALLY CONNECTED TO SAID HOUSING AND ITS OPPOSITE END CONNECTED BY A SPRING TO THE OTHER END OF SAID BLADE AND ADAPTED TO MOVE SAID OTHER END OF SAID BLADE RELATIVE TO SAID PIVOT BRACKET, (B) A BEARING MEMBER EXTENDING THROUGH SAID HOUSING AND HAVING AN OPENING EXTENDING LONGITUDINALLY THERETHROUGH AT A SUBSTANTIAL RIGHT ANGLE AND TO SAID OPPOSITE END OF SAID ACTUATING LEVER, (C) A KEYWAY FORMED IN SAID BEARING MEMBER AND IN OPEN COMMUNICATION WITH SAID OPENING FORMED THERETHROUGH, (D) A ROTOR ACTUATOR JOURNALED IN SAID OPENING FORMED IN SAID BEARING MEMBER AND PROVIDIN AT ONE END A CAM HEAD AND KEY MEMBER PIVOTALLY SUPPORTING SAID OPPOSITE END OF SAID ACTUATING LEVER, (E) SAID ROTOR ACTUATOR CARRYING A CIRCULAR RETAINING PLATE EXTERIORLY OF SAID HOUSING AND IN FACIAL RELATION TO THE EXPOSED END OF SAID BEARING MEMBER, (F) SAID CAM HEAD AND KEY MEMBER IDENTICAL IN CONFIGURATION TO SAID OPENING AND SAID KEYWAY FORMED IN SAID BEARING MEMBER AND PROJECTED THERETHROUGH INTO SAID CAVITY OF SAID HOUSING WITH SAID KEY RADIALLY DISPLACED WITH RESPECT TO SAID KEYWAY TO PREVENT LONGITUDINAL MOVEMENT OF SAID CAM HEAD THROUGH SAID OPENING IN SAID BEARING MEMBER AND OUT OF CONTACT WITH SAID ACTUATING LEVER, (G) AND MEANS PROVIDED BY SAID HOUSING EXTERIORLY OF SAID CAVITY AND ADJACENT TO SAID BEARING MEMBER COOPERATING WITH SAID RETAINING PLATE TO LIMIT ROTATION OF SAID ROTOR ACTUATOR TO PIVOTING OF SAID ACTUATING LEVER TO ACTUATE THE SNAP ACTING MECHANISM AND TO PREVENT HORIZONTAL ALIGNMENT OF SAID KEY WITH SAID KEYWAY AND LONGITUDINAL MOVEMENT OF SAID CAM HEAD THROUGH SAID OPENING IN SAID BEARING MEMBER OUT OF SAID CAVITY AND OUT OF CONTACT WITH SAID ACTUATING LEVER OF SAID SNAP ACTING SWITCH MECHANISM.