US3354275A

US3354275A - Silent electric switch

Info

Publication number: US3354275A
Application number: US490322A
Authority: US
Inventors: Harold E Schleicher
Original assignee: Arrow Hart and Hegeman Electric Co
Current assignee: Cooper Industries LLC; Arrow Hart and Hegeman Electric Co
Priority date: 1965-09-27
Filing date: 1965-09-27
Publication date: 1967-11-21
Anticipated expiration: 1984-11-21

Description

1957 H. E. SCHLEICHER 3,354,275

' SILENT ELECTRIC SWITCH Filed Sept. 27, 1965 3 Sheets-Sheet 1 I I /7 gL3 INVENTOR O o 8; G Po 0E O Hora/c7 Same/Cher BY h/s of/ome s 0 4 244w Nov. 21, 1967 H. E. SCHLEICHER 3,354,275

' SILENT ELECTRIC SWITCH Filed Sept. 27, 1965 5 Sheets-Sheet 2 INVENTOR.

Hora/c7 ESCh/e/Che/ BY his af/omeys United States Patent Ofiice 3,354,275 Fatented Nov. 21, 1967 3,354,275 SILENT ELECTREC SW1T CH Harold E. Schleicher, West Hartford, Conn, assignor to The Arrow-Hart & Hegeman Electric ompany, Hartford, Conn, a corporation of Connecticut Filed Sept. 27, 1965, Ser. No. 49tl,322 Claims. (Q1. 200-68) ABSTRACT OF THE DKSCIBSURE This invention relates to an electric switch and in particular to a switch which is of rugged construction, simple and economical to manufacture and quiet in operation.

The desirability of switches which are quiet in operation for use in home and oflice lighting installations, for example, has long been appreciated and many such devices are currently available. However, previous designs have used over-center coiled springs, and single-action bumper means, and have been diiiicult and expensive to manufacture or have had an undesirably short life as well as perceptible noise level. There has thus been a need for a switch which would operate with minimal noise for an extended period of service. Therefore it is an object of the invention to provide such a device.

Another object of the invention is to provide a switch which is quieter in operation and easily adaptable to single pole, double pole or three way operation.

Another object of the invention is to provide a switch of the class described having a minimal number of parts which may also be assembled in a single operation without machine preassembly.

Another object of the invention is to provide a switch of the class described which is safer than presently avail able designs.

Another object of the invention is to provide a switch of the class defined in which dielectric shorting is suppressed.

Other objects will become clear from a consideration of the following specification and claims.

In accordance with the invention, the enumerated objects and others are attained by means of a switch comprising a hollow casing having at least one side wall with openings for wire terminals; combined terminal and contact members seated edgewise in said casing, oneof said members having a flexible contact portion engageable with and disengageable from another of said members; an operating lever member preferably mounted in said casing, there being on said operating member (i) cam means engaging said flexible portion to cause it to move laterally, for engagement with and disengagement from said other member, the latter being by positive action, and (ii) an ogival cam engaging with novel, silently operating positioning means. For cooperation with the operating lever, there are double-action bumpers on the casing, and a leaf spring and an anti-friction roller, the roller being between the spring and the operating lever.

The invention will be further described with reference to the accompanying drawings in which:

FIG. 1 is an exploded view partly cut away of a switch according to the invention.

FIG. 2 is a bottom plan view of the cover of the switch shown in FIG. 1.

FIG. 3 is a plan view of the bridge shown also in FIG. 1.

FIG. 4 is a plan view of the base of the switch of FIG. 1, the showing being of a switch arranged for three- Way operation, with the operating lever removed.

FIG. 5 is a view in vertical section along the line 55 of FIG. 4, the operating lever and cover being in position in this view, however.

FIG. 6 is a view in vertical section along the line 6-6 of FIG. 4, the operating lever and cover again being in position.

FIG. 7 is a view in vertical section along the line 77 of FIG. 4, the cover again being in position but the operating lever being omitted.

FIG. 8 is a View in vertical section of a pin or roller for use in a switch according to the invention.

FIG. 9 is a perspective view of a movable contact member for use in a switch according to the invention.

FIG. 10 is a view in elevation of a fixed contact memer according to the invention.

FIG. 11 is a perspective view of a bumper for use in a switch according to the invention.

FIG. 12 is a perspective view of the operating lever shown also in FIGS. 1, 3, 4 and 5.

FIG. 13 is a perspective view of another form of operating lever for use in a double or single pole switch.

Fl". 14 is a plan view of a switch base according to the invention arranged for double pole operation, with the operating lever removed.

Referring to the drawings:

As shown in FIG. 1, a switch according to the invention may comprise a base 113, an operating lever member 11 and a cover 12. The cover 12 may be secured to the base by any convenient means. In the embodiment shown, the cover is attached to the base by means of a bridge 13 and screws 14 which pass through

holes

15, 16 in the base and cover respectively and are threaded into tapped holes 17 in the bridge 13.

The embodiment specifically to be described in connection with FIGS. 1-12 is arranged for three-way operation. Referring particularly to FIGS. 1 and 5 to 7, the base it comprises in general a floor 13, two

end walls

19 and 29 and two

side walls

21 and 22. The side wall 21 has a wing 21a extending at its midpoint and two

windows

23 and 24 for receiving the

terminal plates

25 and 26 of a fixed contact 27 and a movable contact 28, respectively. As shown more clearly in FIGS. 9 and 10, fixed contact 27 comprises a flat terminal plate 25 of copper or like metal having an car 29 to which may be aflixed a contact button M. A tapped hole 31 is provided in the plate 25 through which a terminal screw 32 (FIG. 4) may be threaded for afiixing a wire (not shown). The movable contact 28 comprises terminal plate portion 26 and a flexible arm portion which hooks around behind the plate 26. The arm portion has a base section 33a, more or less parallel to the plate portion 26 and. an end section 33/) which is reduced in width compared to the base section and is normally positioned in a plane between the plane of the base section and the plane of the terminal plate 26 by a bent section 330. The end section 33]) supports a contact button 34. The contact 23 is formed of a material, such as bronze, which in the conformation described imparts a substantial degree of springiness to the contact arm. A tapped aperture 35 (FIG. 5) is provided in terminal plate 26 for a terminal screw 36.

The fixed contact 27 is positioned just inside the window 23 in a side wall 21 by means of a slot 37 (FIG. 5)

3 in the floor 18 of the base just outside of the window 23 into which slot the terminal plate 25 of the contact fits. A projection 38 is formed arising out of the floor 18 of the base directly behind the slot 37 which also aids in retaining the fixed contact in position.

The movable contact 28 is positioned in a similar fashion just behind the window 24, its terminal plate 26 fit ting into a slot 39 (FIG. 5) and being supported by a projection 40.

The side wall 22, like the wall 21, has two windows 41 and 42. The terminal plate 43 of a movable contact44, identical to the movable contact 28, is positioned just inside the window 41 in a slot 45 (FIG. 7) supported by a projection 46. A terminal screw 47 is threaded into the plate 43.

A blind contact 48 is positioned in a slot 49 (FIG. 7) just'inside the window 42 and is supported by a projection 50. The contact 48 is identical with the fixed contact 27 except that it has no terminal screw or threaded hole.

The interior of the base is divided into three

compartments

51, 52 and 53 by

internal walls

54 and 55. The

outer compartments

51 and 52 contain the fixed and movable contacts just described. The central compartment 53, as can best be seen from FIGS. 4 and 6, has a V- shaped well 56 in its bottom. Two ledges 57 and 58 are formed On either end of the well and a fiat spring 59s is supported on those ledges. Midway along the inside of

walls

54 and 55 are

vertical channels

59 and 60 in which are positioned the ends of a pin or roller 61, this roller being free to rotate about its axis and to move vertically in the

channels

59 and 60. As indicated in FIG. 8, the roller 61 comprises a metal core 62 and a resilient sheath 63 preferably made of a silicone rubber.

Toward the ends of the central compartment 53 are located two

rubber bumpers

64 and 65. As shown more clearly in FIG. 11, the bumper 64 comprises a block 66 having slightly enlarged section 67 on its upper and lower surfaces and an extension 68 on one face. Bumper 64 is seated on

ledges

69 and 70 formed in

internal walls

54 and 55, respectively, with its extension abutting the inside of end wall 19. Bumper 65 is positioned similarly on

ledges

71 and 72 with its extension abutting the end wall 20. It Will be observed from PEG. 6 in particular, that the

bumpers

64 and 65 are dimensioned so that the tops of the blocks and the uppermost part of the extensions are above the top of the base. It will also be noted from FIGS. 5 and 7 that the terminal plates of the

contacts

27, 28, 44 and 48 also extend above the top of the base 10. Further it will be observed that the top (and bottom) of the terminal plates of each of these contacts is provided with a notch 73. In the three-way switch .depicted in FIGS. l-'7, a bus bar 74 is inserted in the notches 73 of the movable contact 28 and the blind contact 48. As explained below, the cover 12 holds the bus bar 74 in position.

To actuate the switch, the operating lever member 11 is provided. As may be seen more clearly from FIGS. 1 and 12, in the three-way embodiment, this member com: prises a molded insulation handle 75, an arcuate section 76 having two stop surfaces "/7 and 78 and a central section or nose 79 extended in a direction opposite to the handle. This section is tapered downwardly to a pair of shoulders 80, 89a and terminates in a tip 81 which in side elevation is ogival in shape. Extending from either side of the lever is a rocker bar 82, i.e. two arcuate surfaces converge symmetrically and intersect at a line or peak. This has a pie-shaped cross-section with a curved lower surface 83. A short distance in from each end of the rocker bar 82 are camming lugs 84 and 85. In the three-way embodiment shown, these lugs are angularly displaced relative to each other on the rocker bar 82. The

inner surfaces

86, 87 of both lugs are gently curved from the leading edges 88, 89 to a point approximately midway along the inner surface to provide for camming action on the contacts. The outer surfaces such as 90 are flat.

As shown in FIGS. 5-7, the operating member 11 is

walls

21 and 22 and the portions of the bar near the I arcuate section 76 of the member 11 are seated in

arcuate recesses

93, 94 in the

internal walls

54 and 55.

The camming lugs 84 and 85 are provided to separate the movable contact 28 from the fixed contact 27 against the spring action of the movable contact while permitting movable contact 44 to remain in contact with blind contact 48; and to separate

contacts

44 and 48 whilst permitting

contacts

27 and 28 to remain engaged.

In the position shown in FIGS. 4-7, the camming lug 85 is thrust toward end wall 19. Its rounded inner surface 86 has engaged the bent portion of the movable contact 28, camming that arm inwardly and moving its contact button 34 away from the contact button 30 on fixed contact 27 In this position, the other camming lug 84 is in a position also toward end wall 19, but toward the terminal plate43 of movable contact 44 so that it permits the contact button of that contact to engage the contact button of blind contact 48.

As previously pointed out, the base 10 is closed by a cover 12. The cover of insulating material is shaped, as by molding, to receive the various elements which extend above the base. It is provided, for example (see FIG. 2) with slots 95 to receive those portions of the contacts which extend above the level of the base. Studs 96 are provided which extend behind the terminal plates of the fixed and movable contacts to maintain them in proper position. A central aperture 97 is provided for the handle of operating member 11 and the walls 98 of this aperture are curved to accommodate the arcuate section 76 of the operating member. On either side of the aperture 97 are V-shaped recesses 99 to accommodate the V-shaped upper surface of the rocker bar 82. Recesses 100 receive the upper sections of the

bumpers

64 and 65. A long transverse recess 101 is provided for bus bar 74.

The operation of the switch will be obvious. In the position shown, the movable contact 28 is held disengaged from fixed contact 27 by camming lug 85, but movable contact 44 is engaged with blind contact 48. Thus, a line connected to terminal screw 36 of movable contact 28 would be connected via bus bar 74 to blind contact 48 and thence through movable contact 44 to a line connected to the terminal screw 47 of that contact. Moving the handle of the operating member 11 forward, i.e., toward end wall 19 causes the ogival tip 81 to depress the roller 61 against the action of spring 59, the spring moving down into tht V-shaped well 56. Once the roller has passed around the end of tip 81, the roller 61 comes to rest on the shoulder a opposite the shoulder it previously contacted. The spring 59 resumes its straight position and the stop surface 77 comes to rest against bumper 64. Camming lug has in the meanwhile moved back toward end wall 20 and no longer forces the arm 33 of movable contact 88 away from fixed contact 27. Thus the spring action of arm 33 causes its contact button 34 to engage contact button 30 of the fixed contact 27. At the same time camming lug 84 has moved toward the end wall 20, forcing the contact button 44a of movable contact 44 away from the contact button 48a of blind contact 48 and thus disengaging movable contact 44 from blind contact 48 and, hence, from movable contact 28.

The embodiment described above illustrates'the invention as used in a three-way switch. Obviously the same structure may also be used as a single pole switch.

With a few simple alterations, the basic structure may also be converted to a double pole switch. As shown in FIG. 14, in this embodiment the structure of the base 110 is identical to the base of the three-way embodiment except that the movable contact 144, identical with the movable contact 44 of the three-way embodiment, is placed at the window 142 where the blind contact 48 is located in the three-way version, and a fixed contact 148, identical with the fixed contact 27 of the three-way switch. is placed at the window 141.

In place of the operating member 11 used in the threeway version, a member 111 is used. As shown in FIG. 13, the operating member 111 is like member 11 except that camming lugs 184 and 185 are located in transverse alignment on the rocker bar 182.

When the operating member 111 is placed in the base 110, it will be obvious that in one position of the rocker bar both

movable contacts

128 and 144 will be separated from both fixed

contacts

127 and 148, and in the other position both movable contacts will engage both fixed contacts.

The double pole structure just described can obviously also be converted very easily to a single pole structure.

A consideration of the foregoing description will reveal that the present invention provides a simple flexible rugged and economical structure which is quiet in operation and readily converted to a variety of applications. Energy transfer in moving from one position to the other is carried out safely via a simple, flat spring which has a long life.

The switch contacts open sideways so that any arcing will be clear of the walls of the switch, thus to avoid dielectric shorting.

The operating lever with its camming lugs may be made in one piece of a wear resistant material such as nylon which needs no lubrication.

A novel feature of the rubber bumpers is that each provides quiet stopping of the operating member in two directions, vertically by impringement of the stopping surface, such as 78, against the top of the bumpers 65 and horizontally by contact of the nose surface against the end of the opposite bumper 64. This multi-directional stopping is in contrast with the unidirectional stopping common heretofore.

The wings such as 21a and 22a of the

side walls

21 and 22 provide an added safety feature by keeping the terminal screws away from the sides of metal Wall boxes (not shown) in which the switch would normally be mounted. In the three-way version of the switch, the shunt is positively pressed into connection with the terminal plates by the cover bearing thereon.

Another feature of the present invention of particular interest is the operating pin or roller 61 which controls the biasing position of the operating lever. The provision of an elastic sleeve for this roller results in a damping effect on its relative energy association with the operating lever and is responsible to a high degree for the quietness of operation of the switch. The fact that the pin is mounted in tracks or channels guarantees that the pin will retain its desired relationship with the operating lever for the life of the switch.

Finally, it may be pointed out that in the construction shown, the operating lever is positively biased to assume either one position or the other no matter how the lever is manipulated. This overcomes one of the difficulties hitherto experienced in designing quiet switches and enables the present design to meet the rigorous requirements required for Underwriters Laboratory approval.

Modifications within the scope of the invention will occur to those skilled in the art. Therefore, the invention is not limited to the precise forms illustrated and described.

What is claimed is:

1. In an electric switch a hollow insulation casing, fixed and movable contact means mounted in said casing, an over-center operating member pivotally mounted in the casing and moving said movable contact means between switch positions for engagement with and disengagement from said fixed contact means, a leaf spring extending longitudinally of said casing and being supported at its ends, a cylindrical anti-friction roller extending transverse to the leaf spring and engaging the midportion of said leaf spring, said operating member having a convergently formed inner end portion engaging with said anti-friction roller, said spring and roller exerting pressure on the opposite sides of said convergent end portion in different switch positions to bias the operating member therein, and sound-deadening and energy-absorbing resilient bumpers mounted in said casing adjacent the right and left sides of said operating member, each bumper having first and second surfaces angularly disposed with respect to each other, said operating member having first and second surfaces on each of the right and left sides thereof complementary to and engageable with said first and second surfaces of the bumpers, a first surface on the right bumper being engaged by a first surface on the right side of the operating member simultaneously with engagement of a second surface on the left bumper being engaged with the second surface on the left side of the operating member, and vice versa, whereby the two sides of the operating member come into engagement with two bumpers, in each of said different switch positions.

2. A switch as claimed in claim 1 in which the said inner end portion of the operating member has shoulders on opposite sides of said end portion against which said roller rests to assist in positively biasing said operating member in said different switch positions.

3. A switch as claimed in claim 1 in which the roller is a rigid cylindrical pin whose ends are located in and guided by slots in said casing to maintain a constant positive relationship between the roller and operating member during the life of the switch, said roller having a sleeve thereon of sound-deadening elastomeric material.

4. A switch as claimed in claim 3 in which said sleeve is of silicone rubber.

5. An electric switch for quiet operation as claimed in claim 1 wherein the movable contact means is formed of a flat flexible metallic strip mounted in said casing edgewise for movement toward and from the plane of movement of the operating member, said operating memher being formed with camming means engaging with said strip to move the movable contact between said different switch positions.

References Cited UNITED STATES PATENTS 2,085,217 6/1937 Hart.

2,669,613 2/ 1954 Despard.

2,807,683 9/1957 Bettencourt.

2,950,366 8/1960 McRoberts et al 200-68 2,969,442 1/ 1961 Benander et al.

1,778,676 10/1930 Kempton 200-166 2,903,531 9/1959 Winter I 200-466 2,927,184 3/1960 Hubbell 200-466 ROBERT K. SCHAEFER, Primaly Examiner. D. SMITH, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,354,275 November 21, 1967 Harold E. Schleicher It. is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, lines 66 to 68, strike out i.e. two arcuate surfaces converge symmetrically and intersect at a line or peak" and insert the same after "shape" in line 65, same column 3; column 5, line 38, for "impringement" read impingement column 6, list of References Cited, add

the following references l ,694 ,928 12/1928 Rider FOREIGN PATENT 254,709 8/1956 Great Britain Signed and sealed this 17th day of December 1968.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. IN AN ELECTRIC SWITCH A HOLLOW INSULATION CASING, FIXED AND MOVABLE CONTACT MEANS MOUNTED IN SAID CASING, AN OVER-CENTER OPERATING MEMBER PIVOTALLY MOUNTED IN THE CASING AND MOVING SAID MOVABLE CONTACT MEANS BETWEEN SWITCH POSITIONS FOR ENGAGEMENT WITH AND DISENGAGEMENT FROM SAID CONTACT MEANS, A LEAF SPRING EXTENING LONGITUDINALLY OF SAID CASING AND BEING SUPPORTED AT ITS ENDS, A CYLINDRICAL ANTI-FRICTION ROLLER EXTENDING TRANVERSE TO THE LEAF SPRING AND ENGAGING THE MIDPORTION OF SAID LEAF SPRING, SAID OPERATING MEMBER HAVING A CONVERGENTLY FORMED INNER END PORTION ENGAGING WITH SAID ANTI-FRICTION ROLLER, SAID SPRING AND ROLLER EXERTING PRESSURE ON THE OPPOSITE SIDES OF SAID CONVERGENT END PORTION IN DIFFERENT SWITCH POSITIONS TO BIAS THE OPERATING MEMBER THEREIN, AND SOUND-DEADENING AND ENERGY-ABSORBING RESILIENT BUMPERS MOUNTED IN SAID CASING ADJACENT THE "RIGHT" AND "LEFT" SIDES OF SAID OPERATING MEMBER, EACH BUMPER HAVING FIRST AND SECOND SURFACES ANGULARLY DISPOSED WITH RESPECT TO EACH OTHER, SAID OPERATING MEMBER HAVING FIRST AND SECOND SURFACES OF THE BUMPERS, AND "LEFT" SIDES THEREOF COMPLEMENTARY TO AND ENGAGEABLE WITH SAID FIRST AND SECOND SURFACES OF THE BUMPERS, A FIRST SURFACE ON THE RIGHT BUMBER BEING ENGAGED BY A FIRST SURFACE ON THE RIGHT SIDE OF THE OPERATING MEMBER SIMULTANEOUSLY WITH ENGAGEMENT OF A SECOND SURFACE ON THE LEFT BUMPER BEING ENGAGED WITH THE SECOND SURFACE ON THE LEFT SIDE OF THE OPERATING MEMBER, AND VICE VERSA, WHEREBY THE TWO SIDE OF THE OPERATING MEMBER COME INTO ENGAGEMENT WITH TWO BUMPERS, IN EACH OF SAID DIFFERENT SWITCH POSITIONS.