US3253111A - Silent operating multi-circuit push-pull switch - Google Patents

Description

SILENT OPERATING MULTI-CIRCUIT PUSH-PULL SWITCH Filed Aug. 22, 1963 2 Sheets-Sheet 1 FIGZZ INVENTORS PAUL H. m/vrm GUIVTHER s. GRIESHABER ATTORNEYS United States Patent 3,253,111 SILENT OPERATING MULTI-CIRCUIT PUSH-PULL SWITCH Paul H. Winter, Syracuse, and Gunther S. Grieshaber, Camillus, N.Y., assignors to Pass & Seymour, Inc., Syracuse, N.Y., a corporation of New York Filed Aug. 22, 1963, Ser. No. 303,751 12 Claims. (Cl. 200-167) This invention relates to multi-circuit switches and more particularly to such switches of the push-pull type suitable for use on panels, dashes, cabinet fronts and the like.

It is a general object of the present invention to provide a novel and improved type of push-pull, multi-cirouit switch having two circuit closing positions each arranged to handle a pair of different circuits.

More particular-1y, it is an object of the invention to provide a switch of the push-pull type of extremely oompact and rugged construction adapted for silent operation whereby it may be used in flight trainers and similar devices without giving any warning to student pilots that a condition change has been made.

An important object of the invention resides in the construction and arrangement of the component parts of the switch contributing to low cost and facility of assembly, etc.

A particular feature of the invention resides in the manner of mounting the stationary contacts whereby the terminals thereof are conveniently grouped on the rear face of the switch housing to facilitate wiring, contact mounting and numbering.

Another important feature of the invention resides in the arrangement of the movable contact assembly and operator providing guidance, silencing and detent means to hold the switch in either of its two positions.

A further important feature resides in the mounting and circuitry for a knob housed lamp.

Other and further objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the following specification and the accompanying drawings wherein is disclosed a single, exemplary embodiment of the invention with the understanding that such changes and modifications 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 an exploded side elevational view of the switch partially in longitudinal central section;

FIGURE 2 is a side elevation thereof;

FIGURE 3 is a rear elevation thereof;

FIGURE 4 is a top plan view of the housing and its assembled stationary contacts, with the cover and movable contact carrier removed;

FIGURE 5 is a vertical longitudinal section taken on line 55 of FIGURE 4;

FIGURE 6 is a fragmentary longitudinal sectional view taken on broken line 6-6 of FIGURE 5 and looking in the direction of the arrows;

FIGURE 7 is a side elevation of the assembled movable contact carrier and its stern;

FIGURE 8 is an end elevation of the assembly of FIGURE 7 looking from the left; and

FIGURE 9 is a schematic circuit diagram of the switch.

Panel mounted style switches for many uses have been of various types, rotary, oscillatin push, snap, etc., many of which are not satisfactory for specific applications. For instance, in certain types of flight trainers using relatively low voltage direct current it had always been considered necessary to use snap switches for operation by the instructor to simulate and program various conditions to 3,253,111 Patented May 24, 1966 "ice which the student pilot must make proper responses. It has been found nearly impossible to completely isolate the click of the switches when operated, and as the noise served as a warning to the student pilot that something was about to happen, the trainer manufacturers have been in quest of completely quiet push button switches, but switch manufacturers have been unable to meet the demand because of the presumed need for a snap acting switch on direct current even on the low operating potential of twenty-eight volts.

It has now been demonstrated that a slow make and break switch is entirely adequate for this voltage and the switch about to be described has proved it in practice on aviation training devices requiring two circuit, three-way switches.

Referring first to FIGURE 9 for a circuit arrangement for which the present switch is well adapted but to which it is by no means restricted, it will be seen that terminal 1 can be alternatively connected to terminals 3 or 2 by pushing or pulling on bridging member 10 and that by simultaneously moving the other bridging member 11, terminal 4 can be connected to terminal 6 or terminal 5. Terminals 7 and 8 are continuously connected to the handle housed lamp 12 independently of the position of the switch operator.

FIGURES 1 to 8 illustrate a panel mounted switch and its components constructed in accordance with the present invention and comprising a housing 15 of a suitable plastic insulating material molded to the rectangular plan illustrated in FIGURES 1 to 3 having flat side walls 16 of approximately square shape, elongated end walls 17, the open top 18 and the closed bottom wall 20.

Arranged within the housing are a plurality of sets of stationary contacts and a movable bridging contact for each set, the arrangement of which is illustrated schematically in FIGURE 9 as explained above. The numhens in FIGURE 9 from 1 to 8, inclusive are representative of terminals on the rear wall 20 of the housing as indicated in the circles in FIGURE 3, which numbers are impressed on the insulating material for identification purposes in wiring, except for the one numbered 8 which is stamped on a metal strap as will appear hereinafter; As seen in FIGURE 9, although more may be used, there are two similar sets of stationary contacts and bridging members. As shown in other figures one set of stationary contacts is arranged along each end wall 17 of the housing.

The movable contacts 10 and 11 are generally of U- shape and are straddle mounted on a plastic carrier 21 best seen in FIGURES 7 and 8, and this is fitted with longitudinally directed ribs 2-2 on its outer edges adapted to be guided in longitudinal grooves 213 in the end walls 17 of the housing, for reciprocation therein under the control of an operating plunger 24 connected to the carrier as seen in FIGURES l and 7. This plunger is hollow and formed of metal and insulated by a plastic sleeve 25 and is reciprocally mounted in a second insulating sleeve 26, best seen in the exploded view of FIGURE 1, having a reduced end which is received in the mouth of a bore in the spigot 27 which acts as a guide therefor. The outer end of operating stem 24 is internally threaded as seen at 28 to receive the threaded metal sleeve 29 about which is molded the translucent operating knob 29'.

The spigot 27 is secured by suitable means to the closure plate 30 of sheet metal which closes the open end 18 of the housing 15 over a plastic cover 31, and is secured to the housing by means of integral straps 32 extending a slight recess in this thickened wall.

the hooks snap over rounded protuberanices 36 to hold the cover in position and the whole switch assembled.

The spigot 27 is used for mounting the switch in a panel such as 40 appropriately drilled to receive it and is fitted with a pair of lock nuts 41 and 42 as seen in FIGURES l and 2, which may be adjustable along the length of the spigot and appropriately spaced apart in accordance with the thickness of the panel. A washer is arranged beneath each nut as shown, one of them having an extension with the downturned end 43 which passes through a secondary lateral hole in the panel to prevent the washer from rotating. Although not shown this washer has an inwardly projecting lug received in a longitudinal groove on the outer surface of spigot 27 to lock it also against rotation in respect to the panel.

FIGURE 6 shows in enlarged detail the connection of the respective external terminals 1 to 6, inclusive, to their internal contacts and the specific terminal 3 in FIGURE 6 is connected with portion 44 within the housing and resting against the bottom wall thereof. Intermediate 3 and 44 is the shank 45 which passes through and closely engages the walls of slot 46 in the bottom. wall 20 of the housing. The shank 45 is wider than the terminal and has side lugs 47 which are partially severed by the cuts shown and flared outwardly to engage over the outer surface of wall 20 and lock the combined contact and terminal rigidly in position in the housing. In a like manner all of the other terminals are secured in position and attached to their respective internal contacts, which may be of different shapes but nevertheless have some form of enlargement which prevents them from being pulled through the rear wall by engaging its inner face.

The centrally disposed terminal 7, shown in FIGURE 3, is illustrated in greater detail in FIGURE where it is seen to be substantially a piece of metal having a shank 50 which passes through a circular opening in the thickened outer portion of the rear wall 20 of the housing and has an integral head 52 resting on the bottom of Where the shank 50 extends outside of the housing it is secured by a spring washer 51 and then reduced in diameter to form the terminal 7 and transversely drilled at 53 to receive a conductor. The shank 50 has an internal extension 55 beyond the disc 52 which is in tubular form and is longitudinally split to closely receive and electrically contact with the metal rod 56, seen in FIGURES 1 and 7, extending through a large portion of the operating stem 24. This rod slides longitudinally within split sleeve 55 and maintains electrical contact with terminal 7 irrespective of the position of the operating stern. This also helps guide the operating stem 24.

The terminal 8 differs from any of the previously described ones. It comprises a fiat metal strap 57, FIG- URES 2 and 3, secured against the outer surface of a side wall 16 of the housing, extending from its insulating cover 31 beyond its rear face to form the perforated terminal 8 and is secured to the wall 16 by the pair of screws shown.

The terminal plate 57 closes the outer end of a bore through the side walls 16 beneath it, which slidably houses the detent 58 in the form of a metal cup having the semi-spherical inner end. It is pressed inwardly by helical spring 59 stressed between its bottom and the under surface of terminal plate 57, as seen in FIGURE 4, whereby the detent is pushed against the surface of metal sleeve 60 at the inward end of the operating stem. This sleeve has the spaced grooves or channels 61 therein to be engaged alternately by the detent to hold the operating stem in either of its two alternate positions and to electrically connect it to the terminal 8.

As viewed in FIGURE 4 each side wall of the housing cup is longitudinally groove throughout its full length as at 62 and provided with an undercut 63 whereby a flat terminal plate 64 may he slid longitudinally in position therein from the open end, carrying with it its terminal plate, such as described in connection with 44 in FIGURE 6, and it is prevented from extending through the opening 46 for its terminal plate by a transverse kink 56 bent therein and housed below the upper surface of bottom wall 20 in a depression 67 therein. It will be noted that the contact plates associated with similar terminals 1 and 4 are diagonally opposite each other in the two side walls. Each contact plate 64 is of such length that it is continuously in contactwith one of the sliding springs on one of the movable contacts 10 or 11, and the other arm of that spring is arranged to alternately engage one of two contacts in the oppositely facing longitudinally directed channel and since each channel is equipped with similar pair of contacts but one will be described. It will be noted that the channels 70 are as wide as the distance between the undercuts 63 in the channels 62 and of the same depth.

As viewed in FIGURE 5 the contact connected to terminal 2 has its main shank portion 72 lying against the bottom of groove 70 and in alignment with terminal 2 on the outside of the housing. Near its inner end it is bent at right angles so as to form the extension 73 and again at right angles to form the contact surface I portion 74 whose outer face is flush with the inner surface of the side wall 16.

A block of insulating material 75 is fitted against the shank 72 and the offset 73 and extends for the full width of the slot 70. It is notched out at 76 for the wing 77 which extends at right angles from the terminal shank 44, previously described, and is co-planar with 74 and the outer face of the insulating material 75, as indicated by the dotted lineshowing its face in FIG- URE 5. In this wise one of the lobes of a straddle mounted bridging contact 10 or 11 can engage either 77 or 74 dependent upon the position of the contactcarrier and its shank, while its other arm continuously engages a straight contact such as 64, whereby the circuit of 1 or 4 is transferred to either 2 or 3 or 5 or 6, dependent upon which group of contacts is considered. It will be noted that the actual contacting portion 77 is bent at right angles to the shank portion 44, as seen in FIGURE 4. It will be noted that the insulation block 75 is held securely in position by being sandwiched between 72 and 77 on its faces and between 73 and the bottom wall 20 on its ends, and having its sides engaging the side walls of channel 70.

Because the double contacts are spaced closer to the center lines of the housing than the individual contacts 64, the offset shape of the contact carrier 21 as shown in FIGURE 8 is resorted to to properly dipose the movable contacts and it should be noted that they are secured to the carrier respectively by hollow rivets 80 seen best in FIGURE 8. Each of the contacts 10 and 11 is generally U-shaped and straddles its side of the carrier closer to the stem thereof than the sliding members carrying the keys 22. The arms of the contacts extend down over the sides of the carrier 21 and each is provided with a struck out semi-spherical knob 82 better to engage and slide over the stationary contacts and the interposed insulation block 75.

Referring now to FIGURE 1 it will be seen that the carrier operating stem 24 is hollow, formed of metal and has the tubular portion 60 containing the detent receiving grooves 61. The lower end of this portion fits over an extension on the contact carrier 21 and is secured thereto against relative rotation by the interlocking key 83 fitting in the slot 84 in the portion 60, best seen in FIGURE 7. The central conducting rod 56 passes through the carrier to secure it against the tubular portion 60 thereof, and a lock washer 85 prevents the extending end from being drawn into the tube. At the opposite end the conducting rod 56 passes through an insulation washer 86, FIGURE 1, which is seated at the bottom of the larger diameter internally threaded bore in the operating shank, and there is fitted with a second lock washer 87 insuring that the the miniature incandescent lamp 12, seen toward the left of FIGURE 1, which is housed Within the tubular metal shank 29 of the plastic operating knob 29. The outer .contact 90 of the lamp has a flared upper end which engages the wall of the shank 29 of the operating knob and connects the other terminal of the lamp to the thin metal sleeve which is threaded at 28 and surrounded by the insulating tubes 25. This then places the lamp in circuit with the central contact 7 on the end of the housing and the side contact plate 57 by way of the detent 59 which engages the sleeve 60 and its lock channels 61.

In order that the switch be silent in operation a heavy rubber annulus 91, FIGURES l, 4 and 5, surrounds the split sleeve 55 and is housed in a recess in the bottom wall of the housing and acts to stop inward movement of the operating sleeve and the carrier assembly in a noiseless manner. Conversely the protruding ends 22' of the carrier keys 22 sliding in the channels 23 in the end walls of the housing are silenced against rubber insets 92 set in notches in the upper edges of the end walls of the housing, as seen in FIGURE 1, being held in diamond shaped recesses therein 93, seen in FIGURE 4, and locked in position by the insulating cover 31.

It will be noted that the switch has no snap action to make any sound, that the detent 59, spring-pressed in the grooves 61, is soundless during operation and motion of the carrier is stopped at either extreme of its travel by substantial rubber cushions so that the switch can well be said to be noiseless.

One of the moving contacts, for each of the two circuits controlled by the switch, bears continuously on its stationary contact and no circuits are broken thereby. The other movable contact breaks one circuit and makes another whenever the position of the operator is changed, but during such change the movable contacts pass over the insulation blocks and any slight arcs which follow the movable contacts breaking with the stationary contacts are quickly snuifed out, at the voltage of 28 used in the circuit, by the relative coolness of the insulation block, it being understood that the circuits are not used often enough, nor do they carry enough current to do any real heating of the insulation parts. Moreover, because of the detent mechanism, movement of the contact carrier on breaking circuit is relatively rapid, since the operator must pull or push on the knob with consider-ably more force than is necessary to normally move the stem and carrier, in order to break the detent out of its groove which results in a rapid movement of the handle and of the carrier so that the circuits are quickly opened sufficiently Wide to prevent arcing and by the same token are closed about as quickly.

We claim:

1. In a switch of the type described, in combination: an insulating housing having a cavity formed by a closed bottom, four side walls, and an open top, a single contact extending longitudinally along one side wall, a pair of separate contacts spaced longitudinally in alignment along an opposite side wall, a bridging contact adapted to selectively connect either of said pair of contacts to said contact, an insulating carrier mounting said bridging contact, a conducting tube secured to said carrier, a cover closing said open top of said housing and having a mounting sleeve secured to and extending therefrom normal to said bottom, said tube being insulated from and guided in said sleeve for reciprocation and having an operating knob on the outer end thereof, and supplemental means to guide said carrier independent of said contacts.

2. The switch of claim 1 in which said supplemental guide means comprises interfitting groove and tongue means on the carrier and an end wall of the housing.

3. The switch of claim 1 in which said knob is translucent, a lamp carried by said tube for illuminating said knob, a conductive rod supported by and insulated from said tube and extending through the carrier toward said housing bottom, a terminal on said bottom and having sliding conductive engagement with said rod, means electrically connecting the lamp to the rod and tube, a second terminal on the outside of said housing and means slidably and electrically connecting the second terminal to said tube.

4. The switch of claim 3 in which said last mentioned means comprises a plunger spring pressed radially toward said tube, and spaced depressions in said tube engageable by said plunger to retain said tube and carrier in each of two diiferent contacting positions.

5. The switch of claim 2 having a conductive rod coaxial and movable with, supported by and insulated from said tube and extending through said carrier toward said housing bottom, a split sleeve on said bottom receiving and electrically contacting said rod and having a terminal extending through and beyond said bottom, and an external terminal electrically connected to said tube whereby current may be continuously supplied to a device movable with and connected to said tube and rod.

6. The switch of claim 5 in which said device is an electric lamp, and a translucent actuating knob secured to said tube and housing said lamp.

7. In a switch of the type described, in combination, an insulating housing of cup-like form having a pair of parallel walls, a single elongated contact extending longitudinally along one of said walls, a pair of contacts spaced longitudinally in alignment along the other wall opposite said first contact, an insulated contact carrier, a bridging contact secured to said carrier and having two oppositelydirected spring-extended contacting areas positioned to slidably engage said single and one or the other of said pair of contacts respectively, cooperating means on the housing and carrier for guiding the latter between and parallel to said contacts, terminals for said contacts extending through the cup bottom, a metal operating tube attached to said carrier, and a mounting spigot attached to said housing and having guide means for said tube.

8. A switch as claimed in claim 7 in which said tube has spaced annular grooves therein, a ball-tipped metal detent slidable in one of said walls, a spring urging said detent against said tube to selectively engage in said grooves to hold the tube, carrier and movable contact in either of two operation positions.

9. The switch of claim 8 in which said tube is of metal, current consuming means carried by and connected to said tube, and a terminal on the outside of said one wall electrically and mechanically engaging said spring to conduct current to said tube.

10. The switch of claim 8 in which a conducting rod extends coaxially within said tube, is connected to said current consuming means, insulated from the tube and extends beyond its end and through the carrier, and a split tube and terminal mounted on the bottom of the cup and slidably engaging said rod.

11. The switch of claim 8 in which there is a resilient cushion at the bottom of said cup and another at the top for engagement by and to stop movement of said contact carrier silently.

12. In a switch of the type described, in combination, an insulating housing of cup-like form having a pair of parallel walls, a single elongated contact extending longitudinally along one of said walls, a pair of contacts spaced longitudinally in alignment along the other wall opposite said first contact, an insulated contact carrier, a bridging contact secured to said carrier and having two oppositelydirected spring-extended contacting areas positioned to slidably engage said single and one or the other of said pair of contacts respectively, a bottom wall on said housing, a channel extending longitudinally in one of said parallel walls for its full length, a slot through said bottom wall having a wall common with said slot, one of said pair of contacts comprising a strap having a portion fitted in said slot against the bottom wall thereof, a terminal tab on said strap extending through said slot and exposed 'outside said' bottom wall, the opposite end of said strap being offset to provide a fiat area for engagement by one of said spring-extended contacting areas adjacent the inner face of said parallel wall, the second of said pair of contacts having a flat area spaced toward said housing bottom wall from and in the same plane as the first one, a lateral extension from said last mentioned flat area engaging another wall of said housing and having a like terminal tab extending through the housing bottom wall, and a block of insulation engaging the inner face of the first strap below the offset therein to space the second flat area therea flat face between and coplanar with said flat contacting areas to facilitate movement of the contact carrier and its contacting areas.

References Cited by the Examiner UNITED STATES PATENTS 3,126,507 3/1964 Clem-inshaw 200-467 X FOREIGN PATENTS 1,297,295 3/ 1962 France.

KATHLEEN H. CLAFFY, Primary Examiner.

BERNARD A. GILHEANY, Examiner.

from, and said block of insulation having a portion with 15 HERMAN JONES, Am'smm Examine!-

Claims (1)

1. IN A SWITCH OF THE TYPE DESCRIBED, IN COMBINATION: AN INSULATING HOUSING HAVING A CAVITY FORMED BY A CLOSED BOTTOM, FOUR SIDE WALLS, AND AN OPEN TOP, A SINGLE CONTACT EXTENDING LONGITUDINALLY ALONG ONE SIDE WALL, A PAIR OF SEPARATE CONTACTS SPACE LONGITUDINALLY IN ALIGNMENT ALONG AN OPPOSITE SIDE WALL, A BRIDGING CONTACT ADAPTED TO SELECTIVELY CONNECT EITHER OF SAID PAIR OF CONTACTS TO SAID CONTACT, AN INSULATING CARRIER MOUNTING SAD BRIDGING CONTACT, A CONDUCTING TUBE SECURED TO SAID CARRIER, A COVER CLOSING SAID OPEN TOP OF SAID HOUSING A MOUNTING SLEEVE SECURED TO AND EXTENDING THEREFROM NORMAL TO SAID BOTTOM, SAID TUBE BEING INSULATED FROM AND GUIDED IN SAID SLEEVE FOR RECIPROCATION AND HAVING AN OPERATING KNOB ON THE OUTER END THEREOF, AND SUPPLEMENTAL MEANS TO GUIDE SAID CARRIER INDEPENDENT OF SAID CONTACTS.

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