US 2953656 A
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Description (OCR text may contain errors)
Sept. 20, 1960 R. A. BATES 2,953,656
A.C. ROCKER SWITCH OF FOUR-WAY TYPE Filed July 17, 1958 2 Sheets-Sheet 1 REG/NALD A. BATES INVENTOR ATTORNEYS Sept- 20, 1960 R. A. BATES 2,953,656
A.c. RocxER SWITCH oF FOUR-WAY TYPE Filed July 17. 1958 2 Sheets-Sheet 2 REGIA/ALD A. 8A TES IN VEN TOR Y @2^ 05ML ATTORNEYS United States Patent O A.C. ROCKER SWITCH F FOUR-WAY TYPE Reginald A. Bates, Syracuse, N.Y., assignor to Pass & eyrxour, Inc., Syracuse, N.Y., a corporation of New Filed July 17, 1958, Ser. No. 749,105
12 Claims. (Cl. 2ML-'67) This invention relates to switches o'f the so-called fourway or double-pole type intended for alternating current service and actuated by a rocker or tumbler type operator.
It is a general object of the present invention to provide a novel, improved and simplied A.C. rocker switch of the four-way type.
More particularly it is an object of this invention to provide in a switch of the type described a unique arrangement of side-by-side springs, each carrying a contact for engagement alternatively with one of a pair of side-byside stationary contacts, together with rocker actuated mechanism actuating said springs, one in the direction of rocker movement and the other in the reverse direction.
An important object of the invention resides in the mechanism for operating the side-by-side springs in opposite directions on movement of the actuating mechanism and in providing positive contact engaging pressure for each spring-carried contact and positive release pressure for at least one of the contacts of a pair.
Another important object of the invention resides in the arrangement of the contacts, springs, supports and the like in the housing of an interchangeable type wall switch whereby the latter may be back wired to facilitate use in multiple in a single gang outlet box.
A still further important object of the invention derives from the positioning of the terminals for the several contact sets in diiferent planes on the rear face of the switch housing to inhibit circuit interference and facilitate wiring and parts placement in the housing.
An important feature of the invention resides in the use of automatic wire gripping terminals in the switch to reduce its size, contribute to the contact mounting arrangement and to permit enclosing all live parts.
Another important feature of the invention consists in the use of a unitary contact spring spacer and handle oVer-center spring end-support with a unique positioning means therefor.
Still another important feature of the invention consists in the unique spring actuator for simultaneously moving four contact-carrying spring blades arranged in sideby-side pairs and facing sets whereby the springs of one set are moved simultaneously in one direction while those of the other are moved in the opposite direction causing the springs of each pair to partake of opposite movement.
The unique feature of the spring actuator for cooperation with the cantilever contact-carrying springs comprises its direct association with one set of springs and its cam drive for the other set whereby the sets move in opposite directions on each throw of the actuator.
Other and further objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawings and following specication, wherein is disclo'sed a single exemplary embodiment of the invention, with the understanding that such changes and modications may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.
In said drawings:
Figure 1 is a longitudinal, vertical section through a four-way switch, constructed in accordance with the present invention, taken just inside of one housing wall and deviated to include the axes of one pair of conductor wires where they enter the self-gripping or so-called pressure terminals;
Figure 2 is a transverse, vertical section taken on broken line 2-2 of Figure 1, the switch actuator being shown in elevation;
Figure 3 is a bottom plan view of the switch illustrating the placement of the conductor entry apertures; land lFigure 4 is a perspective view of the main housing shell and the contacts and terminals, the near wall being broken away, the contact spring set separator unit being omitted and one stationary contact assembly with its wire terminal being removed to display the lower level terminal for one of the spring sets.
Referring now to the drawings for a better understanding of the invention it should be noted that the molded, insulating housing or body shell 10 for the switch is of the general size and conformation used in switches of the so-called Despard type, interchangeable with other switches of various characteristics, convenience outlets, pilot lights and other components, in a mounting frame and wall plate of the type adapted to accommodate as many as three switches so grouped as to be received in a single-gang outlet box. This puts a definite limitation on the size and shape of the switch housing which is rectangular in plan, as shown in Figure 4, having a closed botto'm 12, open top `13, parallel end walls `14 and parallel side Walls 15 forming the -whole into a rectangular parallelepiped.
The top is adapted to be closed by a removable cover 17 resting on the upper edges 18 of the insulating body shell and secured thereto by a flat metal frame 19 bearing on the cover and having integral straps 20 received in channels 21 in the side walls where they are expanded for locking the frame and cover in position. The iiat top of the frame includes side portions 22 `bordering the central opening and engaging the top face of the cover as well as upstanding tabs 23 at the ends of the opening and each having hole 24 to receive a locking lug from the mounting frame, not shown, for supporting the switch across the face of an outlet box, all in a well-known manner.
For the purpose of providing a four-way switch or as it is sometimes known a reversing double-pole switch, the present device provides for two pairs o'f stationary contact lbuttons, those of each pair being electrically connected together, and for two generally U-shaped springs each carrying a contact on each of its arms, these springs being arranged in side-by-side relationship so that each movable contact may open or close circuit with the stationary contact with which it is mated in a manner which will be later described.
The two generally U-shaped contact springs are best seen in Fig. 4, numbered 26 and 27, the first 26 having the flat bottom 28 and a pair of straight arms 29 extending upwardly at an angle somewhat more acute than degrees from the -base so that the arms converge as shown. Spring 27 has a similar flat base 30 and slightly converging arms. 31 but instead of having straight upper ends as in 4the case of spring 26 the outer ends of the arms are bent outwardly providing the cam engaging tabs 32 Vwhich diverge with an included angle somewhat greater housing along with an underlying connecting strap 36, seen best in Figures 1 and 2. The bases are well spaced apart laterally as seen in Figures 2, 3 and 4 to keep them electrically separated and each is secured to the housing base by an appropriate rivet 37, also passing through the strap, whose hollow stem is headed over at 38 in a shrouded recess on the outer face of the housing bottom and adapted to be covered by an appropriate insulating compound, not shown.
The straps 36 are integral extensions of the automatic wire gripping terminals 39 which lie against the bottom wall of the housing in diagonally opposite corners: thereof. Such a terminal, las best seen in Figure 4 at the upper left, comprises a pair of wings 40` formed by slitting the terminal sheet longitudinally and bending the adjacent edges upwardly from the plane of the sheet, forming a funnel-like opening from beneath wherein a bared conductor may be inserted to spread the wings and be gripped by their edges against withdrawal. Such a terminal is more completely shown and described in the patent to V. R. Despard, 2,748,363, granted May 29, 1956, and since it forms no principal poition of the present invention needs no further description here.
Access to each wire gripping terminal 39 is achieved through a cylindrical opening 41 through the bottom wall of the housing for receiving the bared end 42 of an .itnsulated conductor 43 which is gripped by the wings 40 as shown in Figure 1.
The terminals 39, one for each of the springs, are arranged in diagonally opposite corners of the floor of the housing `and the slots therein extend longitudinally of the housing. The remaining diagonal corners have their iioors elevated as shown at 45 in Figures 1, 3 and 4. Each of these iloors is, perforated, as at 46, to receive a conductor end in the same manner as that described in connection with the terminals 39. The terminals S0, one on each of these elevated iloors extend transversely of the switch housing as seen in Figures 1 and 4. The resilient metal sheet from which they are each formed has a wing bent upwardly at right angles and perforated as at 55, forming a window-like aperture through which lugs 56 struck out from one tab 57, of a U-shaped integral metal structure 58, are bent to lock the wire gripping terminal 50 securely thereto. The structure 58 is generally U-shaped in plan with the parallel tabs 57 forming the sides and the narrower transverse plate 58 forming the bottom. This plate is spaced an appropriate distance from the arms 29 and 31 of the yadjacent pair of springs and is provided with complementary contact buttons 59 and 60 riveted thereto as shown.
With the springs in the retracted normal position, shown in Figure 4, the buttons of complementary sets, one on a. spring and the other on plate 58, face each other but are spaced apart to open the circuits. Each pair of buttons 59 and 60 being on a single metal plate are electrically connected together and to the terminal .50 Land there is lone of the units just described for each of the spring arm sets 29, 31.
The tab 57 at the unattached end of the U, where the inclined wings of the wire gripping terminal are located is deeply V-notched as` at 61, best seen in Figures l and 4, so that its spaced points 611 are positioned closely above the outer edges and ends of the wings preventing them from being lifted as a wire is pressed into position for -contacting therewith. By holding down the outer edges, the wings rotate about these fulcra and open up enough to :admit the wire and then pinch it and prevent any withdrawal.
Each contact and terminal assembly S8 is rigidly mounted in the housing by having integral edge runners l62 on the tabs 57 bent outwardly at right angles and received `in appropriate grooves 63 in the side walls of the housing adjacent the end walls. These vgrooves may be of such length vas to limit the entrance, which is. further limited by the liber insulator 65 formed of .sheet material of inverted U-shape having side walls 66, top 67 and a tab 68 upturlned from one end of the top. This device is positioned with :the tab 68 bearing against the end wall 10 of the housing and with vertical walls 66 engaging respectively the side wall of the housing and the halfhigh partition Wall 70, seen only in Figure 4, which joins the elevated floor 45 to the main floor 12. The liber insulator therefore forms a hood over wire terminal 40 connected to the adjacent spring and serves not only to limit downward movement of the contact land terminal assembly which it engages through integral tab 71, Figure l, but protects the underside of the transversely arranged terminal 50 Iwhere it extends beyond wall 70 and overlaps in a right angled direction the terminal 39 spaced some distance beneath it. As seen in Figure l, if the end 4Z of the conductor engaging the lower terminal should be made too long it would be possible for it to contact the upper one were it not for the insulating protector.
In order to -actuate spring arms 29 and 31 so that a different one of each pair may engage a different one of stationary buttons 60 or S9 of the two pairs thereof and the other of each pair of springs and buttons be disengaged in one position of the switch operator, and then the reverse condition exist when Ithe switch operator is thrown to its opposite position, unique mechanism is constituted in the operator which will hereinafter be called rocken It may appear externally like the usual tumbler or switch lever or, as shown, may have a slightly concave top as at '75 -in Figure 1 so that it can be pushed from the position shown to the reverse position by pressure toward the end 76 and returned by pressure at the opposite end.
Such a rocker is a relatively solid block of insulating material 77 having integral fulcra 78 extending from near the centers of the flat sides 79 thereof and each having a reduced end 80 arcuate at the bottom as at 81 and having sides 82 which are substantially radii about the axis of the arc. These fulcra t in appropriately shaped notches `83 in .the upwardly projecting area 84 on each side of the cover 17. Grooves longitudinally arranged in the lower walls of these notches 83 receive rubber snubber blocks 85 engaging the underfaces of `a fulcra to slow up the movement of the handle-operator and hence quiet its operation. The fulcra are held in position in their respective notches by the overlying iianges 22 on the metal frame 19 engaging the edges 8S of the reduced ends thereof. These flanges were referred to in the earlier description of the frame. The main body of the rocker fits through an appropriate opening `86 in the cover 17.
The lower edge of the rocker indicated at 87 is a cam, the end portions of the curve having longer radii from the center 88 of oscillation than the central portion as clearly seen in Figure l. This cam is continuous on 011e side of the lower face of the rocker, but on the other is interrupted by wide and deep notches 89. Between these notches a portion of the rocker extends down in a semi-circular projection 90 which ydoes not interfere with the cam surface 87.
The upper ends of contact carrying spring arms 29 fit each in one of the notches 89, as shown, so that when the rocker is tilted to the right, as illustrated, the semicircular part 90 engages the left spring 29 where the arrow .indicates and presses it to the left until its contact button 34 engages the stationary button 60, carried on the left plate 58, and the spring is slightly flexed as illustrated to ensure tightness 4of contact. The other spring 29 to the right, by its own resilience, because of its initial converging set, is drawn away from its stationary Contact button 66 as the surface of part 90 has been retracted. The outer wall 91 of right notch 89 has not come into play and would only be useful in the event 0f sticking of the contacts in which case this surface would engage the outer face of the spring and separate the contacts as the rocker was moved.
When the rocker is moved to the position shown in Figure 1 the cam surface 87 on the right, at the position shown by the arrow, engages the wing 32 of spring arm 31 forcing it to the right because of the longer radius at 87 than at the center of the cam. 'Ihis causes engagement between contact button 35 and stationary contact 59 (Figure 4). At the opposite side, however, the other spring 31 has moved inwardly of its own resilience fas the shorter lift of the cam engages its tip permitting it to retract and separate its contact from the stationary one opposing it.
To ensure proper operation of the springs, by means of the cams and the notches -arranged on and n the rocker, they should have considerable resilience tending to draw their arms toward each other to release contact at the proper time but they must not be permitted to move too far in the release direction, and to prevent this spreaders are arranged between the arms of each spring, being formed of insulating material, as shown at 92 in Figure l, illustrating in elevation the one between spring arms 29. It has spaced feet 93 to span the rivet head 37 and rest on the base 27 of the U-shaped spring. Its maximum width adjacent this point is such that it substantially engages the inner faces of spring arms 29 when they are contracted to the minimum desired. It tapers .as shown at 94 to form flat stop faces for these spring arms to limit their inward movement. It is then reduced in width and continues upwardly to limit inward movementof the spring arm tips. The top 95 of the spreader is slightly below the upper edge of the housing and is notched at 96 to receive the projection 97 on the cover 17. The cover engages the spreader top, holds it d-own against the base of the spring and ensures it remaining positioned during operation.
An identical yspreader 94 for the spring having arms 31 is shown in Figure 2. The two spreaders are spaced apart laterally and each substantially engages the outer wall of the housing near its bottom, as seen at 98. The two spreaders are molded of suitable plastic insulating material and are connected together near the bottom by integral link portion 99, having formed Vintegral thereon the lalmost semi-spherical abutment 100 for the lower end of helical spring 101 Whose upper end engages abutment 102 formed integral with the protuberance 90 on the lower portion of the rocker. This helical compression spring being of the so-called over-center type keeps the rocker in unstable equilibrium and ensures against the switch remaining on dead-center but will always force it in one direction or the other as it passes by center 4and hold it tightly in either of its limits of movement. The limits are maintained, not by any fixed stops, but, by pressure of the part 90 on one or the other of the springs Whose button engages a fixed one, and the corresponding resistance offered by the tab 32 of la contacting spring 31 to the further movement of the cam surface. This ensures that the power of the helical spring is always exerted to maintain a pair of contacts in engagement, one at one side and one at the other of the switch.
The switch acts much as an ordinary snap-switch does but the operation is not a true snap for movement of the rocker operator may be cont-rolled by the user, or if flipped the motion is slowed by friction blocks 85 whereby the operation is kept relatively silent. When acting as a four-way switch it may connect either of arms 29 of spring 26 with one of contacts 60 while connecting the opposite arm 31 of spring 27 to a stationary contact 59 on the opposite assembly or, when the rocker is thrown to the other position the connections are reversed. For use Aas a double-pole single-throw switch one arm of each of the springs may be removed.
The switch has the advantage of extreme simplicity in construction and operation, a minimum of moving parts,
no true snap action so that its operation is quiet, while its dimensions are kept within the required limits for the purpose explained. The terminals are all available from the back which permits wiring after assembly in the mounting frame. The contacts are large, formed 0f silver and mounted on springs of high conductivity both for electricity and heat so that overheating never results within the nominal rating of -the switch. Switches of this size can be -built to conduct ZO-amperes at 277 volts A.C. and meet all of the underwriters requirements.
1. In an electric switch of the type described, in combination, an insulating housing, a pair of U-shaped springs of flat conducting material, means securing the base of each spring -independently to the housing bottom in insulating and side-by-side relation, an outwardly facing contact on each arm of each spring intermediate its ends, opposing stationary contacts, one lfor each spring mounted contact, arranged in electrically connected side-by-side pairs mounted for individual contact engagement each by a contact of an adjacent arm of a different spring, an actuator for said springs to ex them for contact engagement comprising a rocker fulcrumed in said housing beyond the spring arm ends for alternate direction partial rotation, spaced deep notches in the edge of said rocker a-t one side thereof receiving the free ends of the arms of one spring to move them in unison in the same direction and cam means at the other side of said rocker engaging the free ends of the arms of the other spring to move them simultaneously and in unison in the opposite direction whereby one spring has one arm contact engaging one contact of a connected pair and the other spring has its opposite arm contact engaging one' contact of the other connected pair and means biasing said rocker to either of its two extreme positions to hold the engaged contacts together.
2. The switch as ldened in claim 1 in which the arms of said springs are set to provide automatic withdrawal of their contacts from the mating stationary ones.
3. The switch as ydeiined in claim 2 in which said rocker is iitted with means to positively and alternately withdraw the arms of one of said springs from contact engagement.
4. The switch defined in claim 1 where two automatic wire gripping terminals are positioned one on each of two diagonally opposite corners of said bottom wall and connected one to each U-shaped spring, the remaining opposite corners of said base being elevated above its general plane, and an auto-matic wire gripping terminal on each such elevated corner and electrically connected to the adjacent pair of stationary contacts.
5. The switch as defined in claim 4 in which the said last mentioned wire gripping terminals each overlies a portion of one of the rst mentioned wire gripping terminals but spaced above it, the iirst such terminals each being adapted to receive a wire through it directed toward the overlying terminal and an insulating sheet engaging beneath each last mentioned terminal to prevent said wire contacting it.
6. The switch as defined in claim 5 in which said insulation sheet has downturned ends bearing on the underlying iirst mentioned terminal to prevent its lifting when a wire is inserted therein.
7. A switch as defined in claim 2 in which said rocker is urged over-center and held at either end of its stroke to maintain contact engagement by a helical spring en gaging it beneath its rocking axis, an insulating spacer fitted between the arms of each U-shaped spring, resting on the base thereof Iand serving to prevent each spring arm from excess separation from its stationary contact, and means integrating the spacers at the bottoms and providing -a `fulcrum for said helical spring.
8. The switch as defined in claim 7 in which a closure cover is provided for said housing, means to secure said cover to said housing and means on said cover engaging and positioning the upper ends of said spacers.
9. An electric switch having in combination, an open top insulating housing rectangular in plan, a pair of conducting plates spaced apart and parallel to the end walls of said housing, a pair of laterally spaced contacts on each plate facing those on the other plate, a pair of separate, generally U-shaped springs of flat metal each having its base secured to the bottom of said housing in a position to locate its arms in confronting but separate relation each to one of the contacts on one of said plates, a tiltable rocker fulcrumed near the open top of said housing on an axis parallel to said plates and Ithe housing bottom, spaced notches in said rocker in an area between said aXis and the housing bottom and each receiving one end of one of the -arms of one of said springs to move these arms simultaneously in the same direction to engage one spring with and disengage the other from its confronting plate carried contact, the free ends of the arms of the other spring being splayed and said rocker having an under surface so cam shaped as to cause movement of the splayed arms in unison in a direction opposite to that of the arms of the other spring when the rocker is tilted.
10. The switch as deiined in claim 9 in which a spacer is fitted between said splayed end arms to limit the retractile movement thereof `from their cooperating fixed contacts.
ll. The switch as defined in claim 10 in which each spring has a separate terminal of the converging wing automatic wire gripping type lying against the bottom wall of said housing and each contact carrying plate has a similar terminal, said last mentioned terminals being each spaced above the plane of the base and at least partially overlapping the irst mentioned terminals.
l2. A stationary contact and terminal assembly for an electric switch of the four-way or double-pole type comprising in combination, an elongated metal plate having a pair of spaced contact buttons side-by-side on one -face thereof, an integral tab extending from each end of the plate in a direction opposite to the button faces, a wire terminal of spring metal having an arm bearing on and attached to the inner face of one of said tabs, and having a right angled portion extending toward the other tab and lying generally in a plane normal to that of the plate, said portion being longitudinally divided into wire gripping wings deflected for wire entrance from beneath, the lower edge of the other tab having a V- notch therein whereby the tongues formed thereby may hold down the outer edges of said wings when a wire is being inserted, and means on said assembly to co-operate with an insulation housing to hold the assembly firmly positioned therein.
References Cited in the le of this patent UNITED STATES PATENTS 2,120,424 Forstrorn lune 14, 1938 2,602,127 Morrison July 1, 1952 2,669,613 Despard Feb. 16, 1954 2,779,828 Despard Ian. 29, 1957 FOREIGN PATENTS 89,539 Norway July l5, 1957