US2527475A - Switch - Google Patents

Description

Patented Oct. 24, 1950 UNITED STATES PATENT OFFICE SWITCH Clifford V. Bates, Chicago, Ill.

Application October 26, 1945, Serial No. 624,694

(Cl. ZOO-444) 6 Claims.

This invention relates to a switch, and more particularly to a switch having its contacts in a hermetically sealed envelope and arranged to be actuated by means outside of the envelope.

- There are many situations in which it is highly desirable to have switch or relay contacts hermetically sealed in an envelope which is either evacuated or filled with an inert gas. One application where this is important, for example, is in aircraft equipment Where the voltage breakdown characteristics would otherwise change with changes in altitude of the airplane. Another situation where this is desirable is in connection with machinery or the like where open contacts would be subjected to a contaminating material such as oil, water, dust, or the like. Hermetically sealed tubes having switch contacts therein, and an actuating member for moving one of the contacts extending through a wall of the envelope, have heretofore been built; but all such hermetically sealed switcheshave had certain defects and objections.

One of the principal defects of prior switches of this type has been that their construction resulted in an exceedingly limited movement of the movable contact, requiring considerable precision and expense in the manufacture of these hermetically sealed switches and in their association with electromagnetic or other motor means for effecting the contact movement. The envelopes are generally of glass, and heretofore the actuating member for the movable contact point has projected through a metal diaphragm or through a glass arrangement intended to have some flexibility. The tubes endeavoring to provide movement by flexibility in a glass portion have utterly failed commercially, breaking so rapidly as to be completely impractical. Tubes making use of a diaphragm have found some application in high voltage circuits, particularly in aircraft, but yhave required expensive mounting and operating arrangements and have had such limited movement that the contact pressure is small and that no wiping action at all can be effected between the contacts.

I have devised and am here disclosing and claiming a relay or switch arrangement with hermetically sealed contacts which overcomes the principal defects and objections in previous switches of this type. Contact members are sealed in an envelope preferably in the form of a glass cylinder' or tube, with a metal bellows hermetically sealed at one end and with the actuating member for the movable contact passing through one .end of the In my construction the bellows and sealed thereto. This arrangement maintains a perfect hermetic seal and obviates any chance of breakage while at the same time providing for a Very considerable movement of the movable member, so that misalignment of contacts can be readily compensated for, heavy contact pressure can be achieved, and vwiping contact can be used. While this switch arrangement can be actuated in any desired manner, I prefer to mount it in operative relation to motor means such as an electromagnet or a solenoid coil, with adjustment of one or the other to enable convenient determination of the range of movement, contact pressure, etc.

One feature of this invention is that it provides a new and improved hermetcally sealed switch arrangement; another fe-ature of this arrangement is that the movement of the movable member may be many times that heretofore possible in such switches; still another feature of this invention is that the switch is particularly rugged and resistant to breakage or damage; yet another feature of this invention is the provision of an improved mounting arrangement for the contacts within the tube envelope greatly simplifying assembly of the parts and minimizing strains which might later result in breakage or misalignment; a further feature is that the switch is adapted to be operated at any desired speed, slow or fast; yet a further feature of this invention is that the switch can be mounted in any position; still a further feature of this invention is that the construction provides for wiping action between the contacts and for heavy contact pressure if desired; and still another feature of this invention is thatthe switch may be readily associated with motor means in such manner as to permit convenient adjustment of contact movement, contact pressure, and the like. Other features and advantages of this invention will be apparent from the following specification and the drawings, in

which: 1

Figure 1 is plan View of a relay or remotely operated switch embodying my invention,l with the housing cover removed: Figure 2 is a fragmentary View corresponding to Figure 1 but with the motor in energized to move the actuatingr member and movable contact within the switch tube: Figure 3 is a sectional view transverse of theswitch tube, along the line 3 3 of Figure 1; Figure 4. is an enlarged fragmentary sectional view of the end of the switch tube having the actuating member extending therethrough; Figure .5 is an enlarged fragmentary view of the conb tact members and mounting, at right angles to the direction of view of these parts in Figure 1; Figure 6 is a perspective View of the contact mounting arrangement shown in Figure 5; Figure 7 is a transverse sectional view along the line 'I-'I of Figure 1, with the cover in place, the apparatus having been rotated ninety degrees; Figure 8 is a view similar to Figure 1 but showing a modified form wherein the motor means comprises a solenoid; Figure 9 is a fragmentary transverse sectional view along the line 9 9 of Figure 8, the apparatus having been rotated ninety degrees; and Figure 10 is an elevational view of another form of switch embodying my inventions, this switch being arranged to operate as a single pole double throw switch.

Referring now rst to the embodiment of my inventions illustrated in Figures 1J?, inclusive, it will be seen that the relay or remotely operable switch comprises three principal parts. These parts comprise the switch tube proper, here identied as A; motor means here identified in general as B; and a housing arrangement identified in general as C. This latter is here shown as comprising a base portion I and side portions II, which may be integrally molded; and a cover part I2.

Referring now first more specifically to the switch A, this will be seen to comprise a glass cylinder or envelope I3 having an opening at one end (the left end as the parts are viewed in Figures 1 and 2) As may be best seen in Figure 4, the glass wall about this opening has sealed thereto an annular member I 4 of metal having substantially the same coeflicient of expansion as glass and adapted to be fused thereto in a good hermetic seal, as the metal sold commercially under the trade name Kovan To this annular member I4 is sealed (as by soldering, brazing or the like) one end of a metal bellows I5. This bellows preferably has a plurality of convolutions, as illustrated, and is of any suitable flexible metal, preferably one not subject to corrosion, as brass or copper. Metal bellows of this type are readily available on the commercial market, being generally termed sylphons The right hand end of the metal bellows (again speaking with respect to the position of the parts as illustrated in Figure 1) is sealed to an actuating member here illustrated as a metal rod I 6. This rod has a portion thereof welded, soldered, or otherwise sealed to the washer II; and this washer is in turn sealed to the inwardly turned end portion of the bellows I 5 to make a hermetic seal between this end of the bellows and the rod member I6. The rod member I6 carries a contact member I8 on the inner end thereof, this contact member in the particular embodiment here being described being of some suitable metal, as silver; and the other end of the actuating member I S projects out through the opening at the left end of the glass envelope I3, so that actuating forces may be applied to this rod member in any suitable manner.

The contact member I8 comprises a movable contact member adapted to cooperate with a pair of spaced spring mounted contact members I 9 and 20, which may also be of silver, for example. Inv the particular embodiment now being described these contact members I9 and 20 are soldered or otherwise suitably -attached to the outer end of a pair of leaf spring members 2I and 22 of suitable metal, as for example phosphor bronze. These leaf spring members are fastened by suitable means, as rivets 23 and 24, to a con tact supporting member 25. This member is of an insulating material suitable for high voltage work, as procelain, and preferably is of rectangular shape (as may be best seen in Figures 3 and 5) with a width slightly less than the internal diameter of the tube I3, and a length somewhat in eX- cess of such diameter. The contact supporting member may, for example, have a width about 10% to 20% less than the diameter of the tube and a length of the order of 50% greater, although it will be understood that these dimensions are not critical. This member 25 has spring means mounted thereon to urge it in a given direction transversely of the glass cylinder I3, this being here shown as an arcuate spring wire 26. Since the transverse dimension of the mounting member 25 is somewhat less than the internal diameter of the glass cylinder I3, the force of the spring against the inner wall of the tube causes the mounting member to settle down into and remain in the position shown in the drawings, the spring serving to locate the supporting member 25 transversely of the tube. In order to prevent the supporting member from moving axially of the tube, and to provide an electrical connection for the contacts carried thereby, connector means here shown as comprising wires 2l and 23 are soldered or otherwise attached to the right-hand ends of the leaf spring members 2| and 22 (again speaking with respect to the posi tion of the parts as shown in Figures 1 and 2) and are passed through and sealed in the glass at the right-hand end of the tube.

This makes a very simple yet satisfactory contact mounting and locating arrangement. The contacts I9 and 20 may be attached to the leaf springs 2i and 22 and these in turn fastened to the mounting member 25 and soldered to the wires 27 and 28; and the spring wire 25 may be suitably attached to the mounting member 25, all of these operations being performed in a convenient manner on a work bench, by suitable machines, or the like. The assembled unit is well shown in perspective in Figure 6, before the connector wires 21 and 28 are attached. After the connector wires are attached the Whole assembly, including the glass stem in which the wires are sealed, may be slipped into the glass cylinder I3 from either end, preferably from the right-hand end, and any minor adjustments necessary may be made. For example, it may appear desirable to straighten out the spring 25 somewhat to increase its pressure; or to bend the connector wires 2I and 28 a little to ensure the stem being properly centered in the openings in the end of the glass tube where it is to be fused to the glass cylinder, without any forcing or strains which might prove undesirable later. After the Contact unit is properly positioned in the glass cylinder I3 the right-hand end would be fused and sealed off. The actuating member and other contact I8 would be hermetically sealed to the metal bellows I5 and this bellows edge would then be soldered or otherwise suitably attached to the annular member I4 which has preferably been fused to the end of the glass cylinder I3 previous to the assembly of the contact unit therein. Proper relation 0f the Contact with the contacts I9 and 20 to bridge across the space therebetween. Because of the very substantial range of movement provided for the contact I8, and the spring mounting of the contacts I9 and 20, any slight difference in height of these later contacts, or of spacing therebetween, is of little importance; and a wiping contact is effected which maintains the best possible electrical circuit conditions, with contact pressure which may be made substantial if desired. It will thus be apparent that a very advantageous hermetically sealed switch is provided, having advantages not heretofore found in switches of this type and yet being rugged in character and simple and cheap to manufacture.

While the outer end IBa of the actuating member may be moved manually, by mechanical means such as cams or in any other suitable manner, I prefer to operate it electrically to provvide what is in effect a relay or remotely controlled switch having hermetically sealed contacts. In the particular embodiment of `my invention now being described I provide an electromagnet comprising the winding 3D and a pole piece 3|. The magnet `winding is wired to suitable connector strips, here identified as 32 and 33, adapted to be connected in any desired control circuit, preferably a low voltage D. C. circuit. The winding is mounted on and surrounds a pole piece 34 mounted on one end of a bracket or L-shaped member 35 pivotally mounted in suitable manner, as by a screw 36. A leaf spring 3'I bears on one arm of the bracket member to urge it downwardly (speaking with respect to the position of the parts as shown in Figure l); and a threaded adjustment screw 38 bears against this same member in a manner opposing the force of the spring 31. This provides a simple adjustable mounting, rotation of the stud or screw 38 serving to cause the face 3m of the pole piece to approach or recede from the cylindrical armature member 39 of magnetic material mounted on the outer end of the actuating rod I 6. The resilience of the bellows member I5 serves to hold the actuating member and contact I 8 in the position shown in Figure 1 when there is no current flowing in the magnet winding 3|); and energization of the magnet winding operates (through attraction of the armature member 39 against the pole piece 3|) to move the actuating member and contact IB to the position shown Figure 2. Adjustment of the screw and thus adjustment of the relative position of the motor and switch means determines the range of movement of the actuating member and contact from their initial position, and thus determines the amount of contact pressure. That is, if only light contact pressure is required the screw 38 would be backed off to cause the pole face 3|a closely to approach the armature member 39, so that energization of the magnet winding would not result in much movement; whereas if yrelatively heavy contact pressure is desired the parts would be positioned with considerable initial spacing between the armature member and pole face, as illustrated in Figure 1, to permit full advantage of the range of possible movement of the contact I8.

Another embodiment of my invention is illustrated in Figures 8 and 9, this differing from the embodiment heretofore described principally in the form of spring used in connection with the contact support member and in the use of a solenoid motor means rather than an relectromagnet. In order to keep this specication as brief as possible, parts shown in Figures 8 and 9 which are analogous and substantially identical with those described earlier will be identified by reference numerals |08 higher than those heretofo-re used, so that reference back to the preceding portions of this speciiication may be used to supplement the description now to be made.

A glass cylinder or envelope ||3 again has a metal bellows I I5 sealed in its left-hand end and serving as a movable support for an actuating'. member IIE carrying a contact member IIB on the inner end thereof. This Contact member is adapted to cooperate with a single cooperating Contact |26. This is again mounted on a leaf spring member here identified as |22 which is in turn mounted on a contact supporting member |25. The contact supporting member is in this case of spring metal and is shown as having an upturned portion at the right end to which the connector wire |23 is fastened by rivets or the like. The principal difference in the contact mounting arrangement in this form is in the shape and location of the spring on the supporting member, this comprising a wing portion on each side of the body portion of the contact member, as the wing portion |26a visible in Figure 8. These wing portions are made of such length that their upper edges will pass the central plane of the glass tube; and they tend to spring apart or have their upper ends move outwardly, this force operating on the sloping inner surfaces of the tube to push the mounting member down to the desired location transversely of the tube.

In this particular embodiment of my invention a circuit is completed from the terminal through the connector wire |28, the conducting supporting member |25, the leaf spring |22 and the contact |28 to the cooperating metal contact I 8 when these contacts are closed; and then the circuit continues through the actuating rod IIE to a spiral spring |46 performing the function of a pigtaiL and thence through the wire I 41 to the other terminal strip |48. That is, in this case the circuit is completed from one contact member to the movable Contact member IIS and then out through the actuating rod member; rather than being completed by bridging across two contacts of the tvpe I am here terming fixed although it will be appreciated that they have movement by virtue of their spring mounting. This arrangement has advantages in certain situations.

Another important difference between this embodiment of my invention shown in Figures 8 and 9 and that shown in the earlier figures is in the motor means for actuating the movable contact member |I8. This comprises a solenoid coil |59 mounted with its axis at right angles to the rod member H5. A movable core member |5| is adapted to move axially in the solenoid coil |50 this core member having an end portion I 5|a, with an opening therein receiving the outer end Iii-a of the rod member H5. As may be best seen in Figure 9, this opening preferably has vertical clearance so that precise alignment of the motor and switch units is not necessary; and has rounded inner walls so that there can be appropriate relative angular movement between the core and actuating member upon energization of the solenoid coil |50, this coil being connected to suitable terminal strips |32 and |33. Adjustment of the amount of contact pressure is determined in this case by the screw |38 which limits the movement of the core member II upon energization of the solenoid.

Referring now more particularly to Figure 10, still another embodiment of my invention will be described, reference numerals 100 higher than those used in connection with Figures 8 and 9 and 260 higher than those used in connection with Figures l-'7 being applied to analogous parts.

The glass cylinder or envelope tube 2l3 again has a metal bellows 2|5 suitably sealed to the annulus at the left-hand end, this metal bellows again serving as a mounting for an actuating member or rod 2l6. The actuating member is indicated in this embodiment as being moved by electromagnetic motor means, only the pole piece 23| and armature member 239 being shown. The "bead or enlarged portion on the inner end of the rod member 2 IB is not in this case one of the metal contact members but is instead a member of insulating material, as glass, for eifecting the desired actuation or movement of a contact, this enlarged portion at the inner end of the rod member being here identified as 2 i612. The contacts here comprise a central movable contact 260 (really comprising upper and lower portions 2600, and 260D) adapted to be normally in engagement with a lower contact 220 and to be moved into engagement with an upper contact 219, these two latter contacts being carried on leaf spring members 22| and 222. The central contact arrangement 250 is carried on a leaf spring member 26| having its central portion enlarged to form a rectangle and provided with spring wings (as the wing 22660, this central portion acting as the contact supporting member; and having an outwardly projecting end v26la adapted to be engaged and moved by the portion 2!6b of the actuating member. Making this portion 2l5b of glass or other suitable insulating material serves to isolate the actuating and motor parts from the circuit being controlled; although it will be understood that this isolation can be effected elsewhere if desired, as by insulating the armature 239 from the rod member 2!6.

In any event, the contact arrangement can be asembled in advance and slipped into the tube, whereupon the action of the spring wings serve to hold it in position transversely. Connector wires 227, 262 and 228 are soldered or otherwise suitably attached tc the spring members and are sealed into the other end of the tube to determine the axial position of the contact arrangement. In the position shown in Figure a circuit is completed between wires 252 and 228, as is readily apparent; whereas energization of motor means associated with this switch tube, and attraction of the armature 239 against the pole piece 23|, causes the end portion 2l6b to engage the end 25m of the central spring member and bring contact 28Ml up into engagement with contact 2l9 to complete a circuit between wires 252 and 221.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modiiications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A switch of the character described, including: an envelope of insulating material adapted to have air excluded therefrom and having a circular opening therein; three contact members in said envelope, two of said members being insulated from each other and being spring mounted and the third being movable into and out of bridging engagement with and disengagement from both of said other members; an actuating member in the form of a pivotally movable rod for moving said third contact member, a portion of this actuating member extending through said opening; and an expansible metal bellows having one end sealed to said actuating member and the other end sealed to said envelope about said opening, angular movement of said bellows causing pivotal movement of said rod to bring said third contact into and out of bridging engagement with said two contact members.

2. A switch of the character described, including: an insulating envelope comprising a cylinder adapted to have air excluded therefrom; rst and second contact members in said envelope, at least one of the contact members being movable and said contacts being in a normally open circuit; an insulating contact supporting member in said envelope having at least one of said contacts mounted thereon; spring means on said supporting member for holding it in desired position transversely of said cylinder; connector means having a portion sealed to said envelope cylinder and a portion connected to a contact member mounted on said supporting member to hold it in desired position axially of said cylinder to maintain said circuit open; and actuating means in said envelope for moving a movable contact member to close said circuit.

3. A switch of the character described, including: an envelope of insulating material adapted to have air excluded therefrom and having a circular opening therein; first and second contact members in said envelope, at least one of the contact members being movable and said members normally being electrically separated; an actuating member for moving a movable contact member, a portion of this actuating member extending through said opening; an expansible metal bellows having one end sealed to said actuating member and the other end sealed to said envelope over an area of substantially greater diameter than the diameter of said rod, said seal being about said opening, said bellows biasing said contact members in their normal position; and motor means operating on a portion of the actuating member outside of the envelope to effect movement of said actuating member to bring said contact members into electrical engagement, this motor means comprising an electromagnet operative on armature means on the last mentioned portion of the actuating member.

4. A switch of the character described, including: an envelope of insulating material adapted to have air excluded therefrom and having a circular opening therein; rst and second contact members in said envelope, at least one of the contact members being movable and said members being in a normally open circuit; an actuating member for moving a movable contact member, a portion of this actuating member extending through said opening; a generally cylindrical expansible metal bellows having one end sealed to said actuating member and the other end sealed to said envelope over an area of substantially greater diameter than the diameter of said rod, said seal being about said opening, said bellows biasing said actuating member to maintain said circuit open; and motor means operating on a portion of the actuating member outside of the envelope to effect angular movement of said actuating member to close said circuit, this motor means comprising a solenoid and a core member connected to the last mentioned portion of the actuating member.

5. A switch of the character described, including: an envelope of insulating material adapted to have air excluded therefrom and having a circular opening therein; three contact members in said envelope, two of said members being insulated from each other and being spring mounted and the third being movable into and out of bridging engagement with and disengagement from both of said other members; an actuating member in the form of a pivotally movable rod for moving said third contact member, a portion of this actuating member extending through said opening; an annular member of metal having substantially the same coeiiicient of expansion as glass sealed to said envelope about said openingj and a generally cylindrical metal bellows having one end sealed to said actuating member and the other end sealed to said annular member, angular movement of said bellows causing pivotal movement of said rod to bring said third contact into and out of bridging engagement with said two contact members, the bridging engagement having sufiicient force to cause yielding of said spring.

6. A switch of the character described, including: an insulating envelope comprising a glass cylinder adapted to have air excluded therefrom and having a circular opening in one end thereof; three contact members in said envelope, two oi said members being spring mounted and the third being movable for engagement with and disengagement from both of said other members, said members normally being out of electrical engagement with each other; an actuating member in the form oi.' a rod for moving said third contact member, a portion of this actuating member extending through said opening; a generally cylindrical expansible metal bellows having one end sealed to said actuating member and the other end sealed to said envelope about said opening, said bellows biasing said actuating member so that said contacts are normally disengaged; motor means operating on a portion of the actuating member outside of the envelope to effect movement of said portion transversly of the cylinder; and means for adjusting the range of movement of said rod to regulate the contact pressure.

CLIFFORD V. BATES.

REFERENCES CITED The following references are of record in the i'lle of this patent:

UNITED STATES PATENTS Number Name Date 809,262 Hood Jan. 2, 1906 1,630,359 Scott May 31, 1927 1,784,303 Millikan et al, Dec. 9, 1930 1,814,851 Prince July 14, 1931 1,845,992 Wise Feb. 16, 1932 1,865,274 Prince June 28, 1932 1,923,350 Wood Aug. 22, 1933 1,940,300 Gerdian et al Dec. 19, 1933 1,997,288 Anderson Apr. 9, 1935 2,029,266 Leece et al. Jan. 28, 1936 2,128,427 Means Aug. 30, 1938 2,197,379 Harrison Apr. 16, 1940 2,285,479 Whitted June 9, 1942 FOREIGN PATENTS Number Country Date 300,649 Great Britain Apr. 10, 1930 309,489 Great Britain June 19, 1930

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