US3210507A - Motion-transfer mechanisms for hermetically sealed diaphragms - Google Patents

Description

Oct. 5, 1965 E. KADlsEvsKls ETAL MOTION-TRANSFER MECHANISMS FOR HERMETICALLY SEALED DIAPHRAGMS Filed May 8. 1961 l PRIOR C ONS TIPI/C 770A/ 4 Sheets-Sheet l fz ver2 on? OC- 5, 1965 E. KADlsEvsKls ETAL 3,210,507

MOTION-TRANSFER MEGHANISMS FOR HERMETICALLY SEALED DIAPHRAGMS Filed May 8, 1961 4 Sheets-Sheet 2 Inventors: Edmunds adzlsea/,S

06f 5, 1965 E. KADlsEvsKxs ETAL 3,210,507

MOTION-TRANSFER MECHANISMS FOR HERMETICALLY SEALED DIAPHRAGMS 4 Sheets-Sheet 5 Filed May 8 Oct. 5, 1965 E. KADIsEvsKIs ETAL MOTION-TRANSFER MECHANISMS FOR HERMETICALLY SEALED DIAPHRAGMS Filed May 8. 1961 4 Sheets-Sheet 4 MNM@ N [nuera fom' E'dmunds Kad Harry ZC J?. y

Atty.

Patented Oct. 5, 1965 3,210,507 MOTION-TRANSFER MECHANISMS FOR HERMETICALLY SEALED DIAPHRAGMS Edmunds Kadisevskis, Pawtucket, RJ., and Harry F.

Rice, Jr., Rochester, NX., assignors to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Filed May 8, 1961, Ser. No. 108,323 Claims. (Ci. 20o- 168) This invention relates to motion-transfer mechanisms for hermetically sealed devices, which are especially adapted for (though not limited to) hermetically sealed electrical switches.

This invention is particularly useful for precision type, hermetically sealed, mechanically snap-acting, electrical switches of the type which are actuated through the application of an externally applied force, which in turn is transmitted to a switching element disposed in a hermetically sealed housing.

Among the objects of this invention are the provision of new and improved motion-transfer mechanisms and devices employing such mechanisms; the provision of such motion-transfer mechanisms which are dependable in operation andeconomical to construct; the provision of such motion-transfer mechanisms which can transfer motion resulting from externally applied forces to the interior of a container which is otherwise hermetically sealed from the circumambient atmosphere; the provision of motion-transfer mechanisms which employ a deformable diaphragm member, which does not depend upon lateral deflection thereof for actuation of the hermetically sealed device with which it is employed; the provision of such motion-transfer mechanisms which, when employed with a hermetically sealed, electrical switching device, render the operation of that device relatively insensitive to ambient or external pressure conditions; and the provision of such motion-transfer mechanisms which employ a deformable diaphragm member which provides for increased life of the diaphragm member and provides for `greater reliability and predictable precision operating characteristics of a hermetically sealed device with which it is employed.

Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated:

FIG. 1 is a side elevational fragmentary view, partly in section, illustrating the operation of an example of prior constructions;

FIG. 2 is a fragmentary elevational view, partly in section, illustrating relative movement between parts, according to applicants invention;

FIG. 3 is a top plan view of an electrical switch embodying one form of the instant invention;

FIG. 4 is an elevational view of the unit shown in FIG. 3, with parts broken away and partly in section, showing interior portions of the switch mechanism;

FIG. 5 is an isometric view of one of the parts according to the present invention;

FIGS. 6 and 7 are sectional views, with parts broken away, taken respectively along lines 6--6 and 7-7 of FIG. 4;

FIG. 8 is a view similar to FIG. 7 showing relative movement between parts;

FIG. 9 is a fragmentary View similar to FIG. 4, according to another form of the instant invention;

FIG. 10 is a sectional View taken on line 10-10v of FIG. 9;

FIG. ll is a view similar to FIG. 9 of yet another form of the instant invention; and

FIG. 12 is a sectional View taken on line 12-12 of FIG. 11.

Dimensions of certain of the parts as shown in the drawings have been modified for the purposes of clarity of illustration.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

When actuating hermetically sealed selectrical switches by means of externally applied forces, it is important that the actuating forces be transmitted to the switching element without disrupting the hermeticallyl sealed integrity of the switch. It has been proposed, in the past, to employ diaphragm members as part of the hermetic sealing enclosure, and to employ relatively stiff motion-transmitting means inside the hermetically sealed enclosure between the diaphragm member and the switching mechanism, to transmit externally applied actuating forces. Such diaphragm members are generally located with respect to the actuating switch button or member (which is hermetically sealed within the switch housing) so that moments will be created and transmitted to the actuating button. These arrangements tend to minimize the amount of lateral deection of the diaphragm member required for actuation of the switching mechanism which has the advantage of increasing the operating life of the diaphragm. Minimizing the lateral deflection required of the diaphragm member also permits employing smaller diaphragms leading toward miniaturization of the switches. An example of such prior constructions is schematically illustrated in FIG. 1, wherein dimensions and movements of parts are exaggerated for purposes of clarity of illustration. The prior construction, for example, illustrated in FIG. 1 comprises an electrical switch 10, which may, for example, be of the mechanical snap type which is disposed within a hermetically sealed housing 12, switch 10` and housing 12 being shown in fragmentary sectional form.

Switch 10 includes a button 14 normally disposed in the solid line position shown in FIG. 1 which, when depressed to the dashed line position, will actuate the element of switch 10. Hermetically sealed housing 12 includes a deformable diaphragm member 16 disposed to one side of button 14 and sealed about its periphery (as by welding) to the housing 12 to maintain the hermetically sealed integrity of the casing 12. The arrangement shown in FIG. l also includes an internal motion-transfer and transmitting means in the form of an L-shaped lever 18. Lever 18 is xed to the diaphragm member 16 in a central portion thereof, represented in FIG. 1 by a point labeled A. Also provided is an externally disposed L- shaped lever 20, the short leg 22 of which is xed to the diaphragm member 16, and to the short leg 24 of internal motion-transfer member 18, as at point A, whereby the internal motion-transfer member will rotate and move in response to rotation and movement of lever upon the application of an externally applied force, as suggested by the arrow in FIG. 1. A characteristic of the prior construction example in FIG. l is that under an externally applied force (as suggested by the arrow in FIG. l) lever 20, internal motion-transfer means 1S and diaphragm 16 will respectively move and twist and deform from the solid to the dashed line position shown in FIG. 1, and in so doing, will cause button 14 to be depressed from the solid to the dashed line position shown in FIG. l to actuate the switch 10. It should be noted that point A of diaphragm member 16, the point of connection between lever 20 and motion-transmitting means 18 and the diaphragm member, also moves laterally to point A', when the parts move from the solid line to the dashed line positions shown in vCFIG. 1. Thus when lever arm 20 is depressed, both a vlateral and a rotational movement is imparted to the internal motion-transfer or motion-transmitting means 18, in addition to causing a lateral deilection of the diaphragm member 16.

Applicants have found that in hermetically sealed devices of the type described, that when actuation of the mechanism, e.g. an electrical switch, depends at least in part upon lateral deflection of the diaphragm member, there is an increased chance or tendency of inadvertent actuation of the switch which would take place by forces other than predetermined applications of mechanical forces. For example, nuisance or inadvertent actuation can take place by changes in ambient pressure conditions in such arrangements.

According to applicants invention, a construction is provided whereby actuation of the hermetically sealed device does not depend upon lateral deflection of the diaphragm, thereby rendering operations of the device substantially insensitive to ambient or external pressures. This construction also provides for greater reliability and predictable precision operating characteristics of the hermetically sealed device.

Referring now to FIGS. 348, a motion-transfer mechanism according to the instant invention has been illustrated in combination with an exemplary, hermetically sealed electrical switch, generally referred to by numeral 70. Switch 70 includes a housing or casing 80 formed, for example, of stainless steel and is hermetically sealed from the circumambient atmosphere. Disposed within hermetically sealed casing or housing 80 is a snap-acting element 82 of the type fully described in U.S. Patent No. 2,630,504 to L. W. Burch et al. For the details of the structure and function of this type of snap-acting element, reference is made to this patent Snap-acting element 82 is supported in tension at two spaced points by posts 84 and 86, respectively. With element 82 so supported, it is warped to the conditions shown in FIGS. 4, 6 and 7, at which an arm 88 carrying an electrical Contact 90 is biased into the position at which the latter contact is disposed in electrically conductive engagement with a stationary contact 92 carried by a terminal 94. Snap-acting element 82 is snappable, by means later to be described, to the condition shown in FIG. 8, at which another movable contact 96 carried by arm 88 is disposed in electrically conductive enga-gement with a stationary contact 98, the latter being carried by a terminal 100. Posts 84 and 86 are carried by a terminal-providing member 102 mounted in a base member 101, by means such as rivets 103, 103. Member 101 is formed of electrically insulating material, such as for example, a moldable phenolic resinous or a ceramic material, and is tixedly disposed in casing 80. All three terminals 94, 100 and 102 provide extensions projecting exteriorly of hermetically sealed housing 22 for connection to external circuits. The externally projecting portions of terminals 94, 100 and 102 are arranged in a conventional manner so as not to disrupt the hermetically sealed integrity of housing or casing 80. Switch also includes a layer of electrical insulation 115 disposed Ibetween element 82 and casing 80, as shown.

Disposed within casing is an internal motion-transfer or transmitting means in the form of a pivotal arm 106. Pivotal arm 106 is provided with a lian-ge 108 which bears against a portion of a flexible diaphragm member 110, which is rmly secured and hermetically sealed, as by welding, to casing 80 and forms a part thereof. This portion of the diaphragm member 110 is represented by a point labeled X in the drawing. Arm 106 further includes a reduced diameter portion 112 extending successively through interlitting apertures in the portion X of the flexible diaphragm member 110 and in a pivotally mounted lever 114 disposed externally of hermetically sealed casing 80. =Pivotal arm or motion-transfer member 106 is headed over, as at 116, to tightly secure the contiguous portions of motion-transfer member 106, the aforementioned portion X of the flexible diaphragm member 110 and 114 together, and soldered to maintain the hermetically sealed integrity of casing 80.

The motion-transfer mechanism according to our invention further includes a stop means which, in the embodiment of FIGS. 3-8, takes the form of a U-shaped bracket, generally referred to by numeral 150, as best seen in FIG. 5. Bracket includes a bight portion 152 and a pair of spaced, substantially parallel, projecting arms 154 and 156, which may be formed integrally with bight portion 152. Arms 154 and 156 are of a generally triangular shape (as best seen in FIG. 5) and include rounded, pointed portions 159 at the free ends thereof providing rigid pivot points.

The spacing between projecting arms 154 and 156 is slightly greater than the width of lever member 114, as best seen in FIG. 6. Bight portion 152, provides an aperture 153 which is disposed directly over and is substantially larger than headed portion 116, to provide access thereto for assembly purposes. Bracket member 150 is disposed about lever member 114 in the area of its connection to portion X of diaphragm member 110, as best seen in FIGS. 4 and 6. Bracket member 150 is secured to lever 114, as by welding, as at 160 and 162, as best seen in FIG. 6, and when so connected, provides a stop means wherein legs 154 and 156 serve as a pair of projecting rocker members which provide rigid pivot points 159 externally of the switch 70. When so arranged, rigid pivot points 169 engage the outer side of diaphragm member 110 adjacent its support with casing member 80. Whereby projecting rocker arm members 154 and 156 are positioned for pivotal supportive engagement with respect to the supporting casing member 80, as best `seen in FIG. 6. When an external force is applied to the left-hand end of lever arm 114, as suggested by the arrow in FIG. 4, lever arm 114 will pivot or rotate about the rigid pivot points 159 and impart a rotational or torsional movement to the diaphragm member 110 to twist or rotate the latter from the solid line to the dashed line position, as shown in FIG. 2. This rotational or pivotal movement of lever arm 114 will also impart a rotational or pivotal movement to internal motion-transfer means 106 to move the lower portion thereof to the right (as seen in FIG. 4 and suggested by the arrow in FIG. 8) against a pin 118 xedly carried by snap-acting element 82, to snap the latter from the position shown in FIG. 7 to the position shown in FIG. 8. When the externally applied force, as suggested by the arrow in FIG. 4, is released or suciently diminished,

the lower end of arm 106 will pivot or move to the left (as seen in FIG. 4) permitting the snap-acting element 82 to snap back to the position shown in FIGS. 6 and 7 under the resilient bias built up in the snap-acting element 82 and the flexible diaphragm 110. Motion-transmitting means 106 is disposed in electrically insulated relation to pin 118, as by means of electrically insulating sleeve 107 disposed about means 106, as shown. The left-hand end of lever 114, as viewed in FIG. 4, is urged for movement upwardly by compression spring 120, which is interposed between casing 80 and lever 114, and maintained therebetween by suitable means, as shown. The pivotal or torsional movement of lever 114, diaphragm member 110 and pivotal arm 106 described above, is permitted by the rocking or pivotal action of rocker arm legs 154 and 156 about its supportive engagement with respect to the casing 80. The stop means 150 through its supportive engagement and co-operation with casing 80, is effective to permit lever 114 to impart rotational or torsional movement to diaphragm 110 and means 106, and to prevent or inhibit lateral or downward (as seen in FIGS. 2 and 4) deection of portion X of the diaphragm member and of motion-transmitting means 106. The term lateral deflection as employed throughout the specification and claims, refers to movement or deflection in a direction which is transverse to, or Which intersects the plane of, the diaphragm member 110, as seen for example, in FIGS. 2 and 4, and for example, as suggested by the arrow in FIG. 6. An example of the type of lateral deflection which the present invention avoids is illustrated by the movement of point A from the solid line position to the dashed line position at A in the exemplary prior construction shown in FIG. 1.

Referring now to FIGS. l and 2, which respectively illustra-te the operation of the motion-transfer means according to an exemplary prior construction, in contrast to that of the instant invention, it can be seen that as lever member 114 (which is fragmentarily shown in FIG. 2) is moved from the solid to the dashed line positions when an external force is applied thereto, bracket me-mber 150 and internal transfer means 106 will rotate from the solid to the dashed line positions shown therein.

It will be noted that as lever 114 and internal member 106 rotate from the solid to the dashed line positions shown in FIG. 2, the diaphragm member 110 will be deformed or twisted from the solid to the dashed line positions shown therein, but that no lateral deflection of portion X of the diaphragm takes place, in contrast to the lateral deection of point A to point A' of the prior constructions, illustrated in FIG. 1, which takes place when lever 20 is rotated to actuate -switch or device 10.

It is to be understood that the motion and deflections which are illustrated in FIGS. 1 and 2 have been considerably exaggerated for purposes of illustration. Stop means 150, in co-operating with the switch casing, lever arm, diaphragm member and motion-transmitting means, in the -manner described above, not only assures that downward or lateral deflection of portion X of the diaphragm will 'be prevented (which might otherwise result upon the application of a mechanic-al force to lever 114) but also assures that such deflection or lateral movements will not take place due to other pressures or forces, for example, external ambient pressures. The arrangement according to our invention thereby renders the operation of switch 70 relatively insensitive to ambient pressure conditions, and assures that actuation will take place only upon the application of a predetermined, externally applied force to lever 114.

Applicants construction, by rendering the operation of the motion-transfer means independent of any requirement for lateral deection of the diaphragm member, provides a number of other advantages which include: permitting the use of smaller diaphragm members to alford device miniaturization; increasing the operating life of the diaphragm member; and eleminiating problems such -as maintaining the lateral spring rate of the diaphragm members constant from device to device and permitting the use of lower cost mass production techniques, while assuring that the devices so produced will have substantially uniform operating characteristics.

Stop means 150, with its rigid rocker arms 154 and 156, may be formed integrally with lever arm 114 or with whatever type of external motion-transfer means is employed.

The modification of FIGS. 9 and 10 illustrates an arrangement 70 wherein stop means comprising rocker arm members 154 and 156' are formed integrally with a lever arm 114 corresponding to lever ar-m 114 of the FIGS. 3-8 embodiment. In the FIGS. 9 and 10 embodiment, like numerals designate parts like those shown in the FIGS. 3-8 embodiment, further verbal description in which respect is unnecessary. Lever arm 114 is secured to diaphragm member 110 and internal motion-transmitting means 106 (fragmentarily shown in FIGS. 9 and 10) in a manner identical to that described above for switch 70.

Except for being formed integrally with lever member 114', projecting rocker member portions 154 and 156 are substantially identical to their counterparts of stop means 150, described above.

T-he rigid pivot points 159 provided by each of rocker members 154' and -156 are disposed for direct supportive engagement with respect to portions of' casing member as clearly shown in FIG. 10. In this regard, it is to be noted that the surface portions of casing member 80 which supportively engage the rigid pivot points 159' are disposed substantially at the same level and in a substantially coplanar relationship with the upper surface of the diaphragm member in the unstressed condition, to assure that when an external force is applied to lever member 114, that no downward lateral deection of portion X of the diaphragm will take place.

The embodiments shown in FIGS. 3-8 and 9-10 precludes lateral deection of portion X of the diaphragm member and of the internal motion-transmitting means in at least one direction, namely downwardly, as seen in FIGS. 2, 4 and 10, toward the interior of the casing 80 and 80'. There may be situations in which it is desired to prevent lateral deection or movement of these parts in an opposite direction, namely in an upward direction, away from the casings, as shown in FIGS. 4, l() and l2. Such opposite lateral deflection might be caused by conditions where the internal pressure in the hermetically sealed package is greater than the external pressures, as might be the case where the hermetically sealed unit is subjected to a vacuum or high temperature conditions. In accordance with another embodiment shown in FIGS. l1 and l2, means are provided for preventing lateral decction or movement of these parts in each of two opposite directions.

`Referring now to FIGS. 11 and 12, there is shown another embodiment of this invention, generally referred to by numeral 70', in which like numerals designate parts like those shown in the embodiments of FIGS. 3-8 and 9410, further verbal description in which respect is unnecessary.

The point of departure in the FIGS. 11 and 12 embodiment from those preceding embodiments, is in the provision of an internally arranged diaphragm stop member generally referred to by numeral 250, which is somewhat similar to U-shaped bracket member shown in FIG. 5. Stop member 250 is U-shaped in form, and includes a bight portion 252 which provides a cylindrical flanged hollow portion 253, the internal diameter of which closely approximates that of the upper portion of internal motion-transfer means 106. The cylindrical portion 253 of bracket member 250 is telescopically disposed about motion-transfer member 106, and is fixedly secured thereto, as by welding at 255, as shown. Bracket member 250 further provides a pair of projecting rocker arm members 254 and 256 which are or may be substantially identical respectively to projecting rocker arm members 154 and 156 of stop means 150. Each of projecting rocker arm members 254- and 256 includes a rigid pivot point 259 disposed at its free end, and positioned for pivotal supportive engagement with casing 80', as best seen in FIG. 12. Bracket member 250. permits motion-transmitting means 106 to pivot or rotate in a manner described above in connection with the embodiment of FIGS. 3-8, and also prevents upward lateral movement or deilection of motion-transmitting means 106 and of portion X of the diaphragm (as seen in FIGS. 11 and 12). Except for preventing lateral movement of parts in an upward direction, as seen in FIGS. 1v1 and 12, stop means 250 function substantially in the manner described above for stop means 150. The FIGS. 9 and 1l embodiments operate in a manner similar to that described above for the FIGS. 38 embodiment, and include substantially all of the advantages of the FIGS'. 3-8 embodiment described above. Y.

The FIGS. l1 and l2 embodiment provides a simple and inexpensive arrangement for transferring substantially pure rotary motion through an external wall of a hermetically sealed enclosure.

It should be understood that while a flat type of diaphragm member has been illustrated in each of the embodiments described above, other types and configurations of diaphragm members may be employed within the purview of this invention.

In the embodiments described above, the external mechanical force transmitting means has been illustrated in the form of a lever 114 or 114. It should be understood that rotational actuating movement can be imparted to internal motion-transfer means 106 in response to an externally applied mechanical force, by other means which could, for example, take the form of a rotating cam member.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could :be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense, and it is also intended that the appended claims shall cover all such equivalent variations as come within the true spirit and scope of the invention.

We claim:

1. In combination; a support having an aperture therein; a diaphragm member secured adjacent its periphery to said support to seal said aperture; motion-transmitting means disposed to one side of said diaphragm member and connected to a portion thereof; lever means disposed -on the other side of said diaphragm member and secured at a part thereof spaced from one end thereof, to said portion of said diaphragm member and said motion-transmitting means; said lever means being adapted to impart rotational movement to Said portion of said diaphragm member and said motion-transmitting means in response to an externally applied force to said lever means; and means secured to and movable with said lever means and having pivot points thereon pivoting on a point adjacent said support whereby said lever means imparts rotational movement to said portion of said diaphragm and motiontransmitting means and prevents lateral movement thereof in at least one direction.

2. In combination; a support having an aperture therein; a diaphragm member secured adjacent its periphery to said support to seal said aperture; motion-transmitting means disposed to one side of said diaphragm member and connected to a portion thereof; a lever member disposed on the other side of said diaphragm member and lsecured at a part thereof intermediate its ends to said portion of said diaphragm member and to said motiontransmitting means; said lever member being arranged for imparting rotational movement to said portion of said diaphragm member and said motion-transmitting means in response to an applied force to said lever member; and stop means comprising a U-shaped bracket member with a pair of spaced projecting rocker members forming the legs of said U-shaped bracket member, the bight portion of said U-shaped bracket member being secured to said lever member as by welding, said rocker members having a pair of pivot points thereon pivoting on a point adjacent said support whereby said lever member imparts rotational movement to said portion of said diaphragm member and motion-transmitting means and prevents lateral movement thereof in at least one direction.

3. In combination; a support having an aperture therein; a diaphragm member secured adjacent its periphery to said support to seal said aperture; motion-transmitting means disposed to one side of said diaphragm member and connected to a portion thereof; a lever member disposed on the other side of said diaphragm member and secured at a part thereof intermediate its ends to said portion of said diaphragm member and to said motiontransmitting means; said lever member being arranged for imparting rotational movement to said portion of said diaphragm member and said motion-transmitting means in response to an applied force to said lever member; stop means comprising a pair of spaced projecting rocker members on said lever member; said stop means having pivot points thereon pivoting on a point adjacent said support whereby said lever member imparts rotational movement to said portion of said diaphragm and motiontransmitting means and prevents lateral movement thereof in at least one direction; and further stop means disposed to said one side of said diaphragm member and engaging said support; said further stop means being connected to and movable with said motion-transmitting means and operative to prevent lateral movement of said portion of said diaphragm and motion-transmitting means in a direction opposite to said one direction.

4. In combination; a support having an aperture therein; a diaphragm member secured adjacent its periphery to said support to seal said aperture; motion-transmitting means disposed to one side of said diaphragm member and connected to a portion thereof; lever means disposed on the other side of said diaphragm member and secured at a part thereof spaced from one end thereof, to said portion of said diaphragm member and said motion-transmitting means; said lever means being adapted to impart rotational movement to said portion of said diaphragm member and said motion-transmitting means in response to an externally applied force to said lever means; and stop means comprising a pair of spaced projecting rocker members secured to said lever member for movement therewith and having pivot points thereon pivoting on said support whereby said lever member imparts rotational movement to said portion of said diaphragm and motion transmitting means and prevents lateral movement thereof in at least one direction.

5. In combination; an enclosure hermetically sealed from the circumambient atmosphere; motion-transfer means disposed within said enclosure and operatively associated with a device also disposed within said hermetieally sealed enclosure for actuation thereof in response to rotational movement of said motion-transfer means; said enclosure including a diaphragm member forming a part thereof; said motion-transfer means being connected to a portion of said diaphragm member; a lever member disposed exteriorly of said enclosure and connected at a part thereof spaced from one end thereof with said portion of said diaphragm member and said motion-transfer means; said lever member being arranged for imparting rotational movement to said portion of said diaphragm member and said motion-transfer means in response to an externally applied force to said lever member; stop means comprising a pair of spaced projecting rocker members `on said lever member and having pivot points thereon pivotally engaging the exterior of said enclosure whereby said lever member imparts rotational movement to said portion of said diaphragm and to said motion-transfer means and prevents lateral movement thereof in at least one direction.

References Cited by the Examiner UNITED STATES PATENTS 5/56 Lung 200-168 8/56 Klingler 7418 X

Claims (1)

1. IN COMBINATION; A SUPPORT HAVING AN APERTURE THEREIN; A DIAPHRAGM MEMBER SECURED ADJACENT IT PERIPHERY TO SAID SUPPORT TO SEAL SAID APERTURE; MOTION-TRANSMITTING MEANS DISPOSED TO ONE SIDE OF SAID DIAMPHRAGM MEMBER AND CONNECTED TO A PORTION THEREOF; LEVER MEANS DISPOSED ON THE OTHER SIDE OF SAID DIAPHRAGM MEMBER AND SECURED AT A PART THEREOF SPACED FROM ONE END THEREOF, TO SAID PORTION OF SAID DIAPHRAGM MEMBER AND SAID MOTION-TRANS MITTING MEANS; SAID LEVER MEANS BEING ADAPTED TO IMPART ROTATIONAL MOVEMENT TO SAID PORTION OF SAID DIAPHRAGM MEMBER AND SAID MOTION-TRANSMITTING MEANS IN RESPONSE TO AN EXTERNALLY APPLIED FORCE TO SAID LEVER MEANS; AND MEANS SECURED TO AND MOVABLE WITH SAID LEVER MEANS AND

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