US3683753A

US3683753A - Dual diaphragm short travel actuator

Info

Publication number: US3683753A
Application number: US9793*[A
Authority: US
Inventors: Jesse R Johnson
Original assignee: AVM Corp
Current assignee: Maremont Corp; Maremont Subsidiary Inc
Priority date: 1971-02-09
Filing date: 1971-02-09
Publication date: 1972-08-15
Anticipated expiration: 1989-08-15

Abstract

A three position vacuum actuator having a housing including two diaphragms clamped between parts of the housing and a fluid communicating spacer ring located between the outer edges of the diaphragms. Fluid communication passages lead into all three chambers formed by the casing and the two diaphragms. Springs are in each of two operating chambers, one spring biasing the diaphragms apart and another spring biasing one diaphragm toward the other. An operator rod extends through the casing wall and is secured to one diaphragm. Diaphragm backup plates have integral structure which interconnect between diaphragms to make a collapsible link unit with an extremely short travel connecting the two diaphragms so they can move toward and away from each other with the separated condition of the two diaphragms being limited. Annular serrations are made on the backup plates.

Description

United States Patent Johnson DUAL DIAPHRAGM SHORT TRAVEL ACTUATOR [72] Inventor: Jesse R. Johnson, Gowanda, NY.

[73] Assignee: AVM Corporation, Jamestown,

[22] Filed: Feb. 9, 1971 [21] Appl. No.: 9,793

[52] [1.8. CI. ..92/48, 92/63, 285/330 [51] Int. Cl ..F0lb 19/00 [58] Field of Search ..92/48, 62, 63, 64, 98-100; 285/325, 330

[56] References Cited UNITED STATES PATENTS 2,693,701 1 1/ 1954 Whitworth et a1 ..92/ 100 2,713,850 7/1955 Bradbury et a1. ..92/100 181,972 9/1876 Packer ..64/10 1,974,850 9/1934 Horton et a1 ..92/48 X 3,048,361 8/ 1962 Francis ..92/50 X 3,077,186 2/1963 De Beaubien et al. ..92/48 3,354,831 11/1967 Acker et a1. .,92/98 UX 3,433,132 3/1969 James ..92/48 FOREIGN PATENTS 0R APPLICATIONS 523,583 7/ 1940 Great Britain ..92/48 [4 1 Aug. 15, 1972 Primary Examiner-Martin P. Schwadron Assistant Examiner-Irwin C. Cohen Att0rney--Strauch, Nolan, Neale, Nies & Kurz ABSTRACT A three position vacuum actuator having a housing including two diaphragms clamped between parts of the housing and a fluid communicating spacer ring located between the outer edges of the diaphragms. Fluid communication passages lead into all three chambers formed by the casing and the two diaphragms. Springs are in each of two operating chambers, one spring biasing the diaphragms apart and another spring biasing one diaphragm toward the other. An operator rod extends through the casing wall and is secured to one diaphragm. Diaphragm backup plates have integral structure which interconnect between diaphragms to make a collapsible link unit with an extremely short travel connecting the two diaphragms so they can move toward and away from each other with the separated condition of the two diaphragms being limited. Annular serrations are made on the backup plates.

14 Claims, 9 Drawing Figures PAT-ENTEDaus 15 1912 SHEET 1 BF 2 INVENTOR JESSE R. JOHNSON PATENTEDmc 15 m2 SHEET 2 (IF 2 INVENTOR JESSE R. JOHNSON WV/hi/Mg CROSS REFERENCE TO RELATED APPLICATION This invention is an improvement over the three position actuator disclosed and claimed in my copending application, Ser. No. 723,862, filed Apr. 24, 1968 now US Pat. No. 3,613,513, issued Oct. 19, 1971.

BACKGROUND OF THE INVENTION This invention relates to multi-position expansible chamber actuators and more particularly to a three position vacuum actuator useful for control operations such as shifting valves, fresh air dampers and the like on automotive equipment or other apparatus. It was developed in order to enable an extremely short travel of the actuator rod clue to movement of one diaphragm toward the other.

SUMMARY OF THE INVENTION which has two diaphragms, one of which is connected to an operating link, and including a lost motion collapsing link assembly connecting between the two diaphragms and constituting identical facing backup plates with integral interconnecting link pieces.

Still another object resides in the provision of an efficient three position actuator which eliminates need for moving seal fittings and maintains the overall length dimensions to a minimum by avoiding housing extensions.

Other objects reside in provision of a novel three position dual diaphragm actuator wherein the actuator requires no external projection to accommodate the three position feature; the diaphragms are interconnected by integral hooks and eyes on the facing backup plates located in the space between diaphragms; the collapsible link assembly will hold the two diaphragms at a fixed maximum distance apart of short dimension; and special annular embossments on the diaphragm backup plates provide better gripping of the diaphragm inner periphery between backup plates when they are riveted together.

Further novel features and other objects of this invention will become apparent from the following detailed description, discussion and the appended claims taken in conjunction with the accompanying drawings showing preferred structures and alternative embodiments, in which:

FIG. 1 is a sectional view of a preferred embodiment of an actuator made in accordance with the present invention, illustrating the extended position of the actua tor operating rod when neither of the operating chambers have a vacuum source connected thereto;

FIG. 2 is a sectional view similar to FIG. 1, showing the operator rod and the two diaphragms in shifted position when the rear chamber is subjected to vacuum;

FIG. 3 is a sectional view similar to FIGS. 1 and 2 showing the position of the operator rod and diaphragms when vacuum is applied to both operating chambers (middle and rear) and the link assembly between diaphragms is in a fully collapsed condition;

FIG. 4 is an enlarged plan view of one of the diaphragm support discs used on the side of both diaphragms which confine the intennediate chamber;

FIG. 5 is a section view of the facing support disc taken on line 5-5 of FIG; 4 and shows the integral eyelet lug forming one part of the collapsible connection;

FIG. 6 is a section view of the facing support disc taken on line 6-6 of FIG. 4 and shows the integral hook lug forming the other part of the collapsible connectlon;

FIG. 7 includes a section view of the facing support disc taken on line 77 of FIG. 4, showing transverse sections of both the eye lug and the hook lug which are integral parts of the disc, as well as a second disc, in section, inverted above the first disc to illustrate pre-assembly disposition;

FIG. 8 is an enlarged detail section through the center portion of a diaphragm support disc to show the minute annular serrations used to grip the diaphragm; and

FIG. 9 is a perspective view of the collapsible link diaphragm discproviding details of the eye lug and the hook lug.

The disclosed actuator can be used to control valves in automotive heating systems and cooling systems, in which, for example, two different rates of flow of fluid through a valve as well as a valve shut-off condition are desired. The actuator could be used to operate something other than a fluid control valve, for example, and again referring to the automotive field, it may be used for setting the positions of heater duct dampers and outlet control doors. Suitable sources of vacuum, e.g., 10 inches to 20 inches Hg, are normally available in automotive installations and the present actuator can utilize such available vacuum pressures.

The actuator 20 shown in FIGS. l3 can be mounted on a support bracket not shown, the actuator being secured by bending over several integral lugs 22 which are part of the actuator housing. In lieu of the lugs 22, other components such as threaded studs welded to the actuator housing can provide the means for fastening the actuator to a support structure. The actuator in FIGS. 1-3 has a flat operator rod 24, its terminal end being apertured at 26 to enable connection with a device being operated. When the actuator is used to operate a plug valve, if operator rod 24 is in the extended condition (FIG. 1) the valve is in one of its limit conditions, e.g., valve open. When actuator 20 is moved to its other limit position, rod 24 is retracted (FIG. 3) causing rotation of the valve plug to its other limit position, e.g., full closed. The intermediate position of the three position actuator 20 locates the valve plug intermediate the two limit positions.

In some installations where the unit being shifted by the actuator moves in an arc, the actuator operator rod 24 must tilt relative to its illustrated alignment with the inline axis of the actuator housing, as it is retracted. This feature of the actuator operator rod tilting or deviating from a straight line path is accommodated by the internal construction of the actuator and is noted because the exemplary actuator assembly has this ability, not normally present in three position actuators, and it can be utilized to avoid the need for additional articulation links which are expensive and require added space.

FIGS. 1, 2 and 3 illustrate a preferred construction of an actuator which while using principles disclosed and claims in the aforedescribed copending application, has modified structure developed to provide short increments of actuator rod movement. Actuator 20 is a three position, dual diaphragm, spring return vacuum actuator, in which the two diaphragms and 32 are contained within a two part casing or housing 34 consisting of a cup 36 and a cover 38. The housing parts can be pressed from sheet metal or molded from suitable plastics, the material used normally being dictated by the environmental temperature. The

outer peripheries

40 and 42 respectively of the two

diaphragms

30 and 32 are spaced apart by a spacer ring 44 and are clamped in sealed relationship between portions of the housing 34 and adjacent end surfaces of the spacer ring 44 when housing cover 38 is secured to the cup 36. Cup 36 has a lateral peripheral flange 46 which with the peripheries of the diaphragms and the spacer ring fit into a stepped peripheral construction 48 on the cover. The peripheral extremity 50 of cover 70 is bent inwardly, over the cup flange 46 and rigidly secures and I sealingly clamps the two diaphragms and spacer in assembly within the housing.

A vacuum connector 52 extends outwardly from the outer periphery of the spacer ring 44 and provides a fluid passageway from the exterior to the interior of the housing into the middle chamber 54 between the two diaphragms. The stepped periphery of cover 38 is notched to slip over the connector 52 and permit as sembly of the components.

A second vacuum connector 56, fastened to the wall of cup 36, provides a fluid passageway from the exterior to the interior of a chamber 58 between the cup and diaphragm. (Chamber 58 for convenience will be designated the rear chamber). The end wall 60 of cup 36 is apertured with an inwardly directed slight extrusion into which the end of connector 56 is fitted and suitable bonded. When both the cup and the connector are made from metal, as is preferable for higher temperature installations, the bonding can be made with silver solder. When cup and connector are made from plastic (lower temperature operating conditions) they can be molded as a unit or joined by suitable plastic bonding agents.

Thus two connections for vacuum are provided, one to the middle chamber 54 and the other to the rear chamber 58. The chamber 62 (which will be designated as the front chamber for convenience) provided between the diaphragm 32 and cover 38 is open to ambient or atmospheric pressure through a cover opening, e.g., the central opening 64 in the cover end wall 66. The actuator operator rod 24, which is directly connected to front diaphragm 32, projects through the cover opening 64.

The inner peripheries of the two

diaphragms

30 and 32 are firmly clamped between two metal support plates or discs made with slightly cupped outer peripheries. Disc plates and 72 are coaxially clamped on the front diaphragm by a centrally located rivet 74 and

disc plates

76 and 78 are clamped on the rear diaphragm by a centrally located rivet 80. The

outer discs

70 and 78 are similar to each other and the respective inner or facing

discs

72 and 76 are similar to each other. Rivet 80 is used only to clamp the

rear discs

76 and 78 on the rear diaphragm whereas the slightly longer front rivet 74 also serves to secure the flat operator rod 24 to the front diaphragm, passing through an aperture in bent end 82 of the rod and tightly clamping the rod 24,

discs

70 and 72 and diaphragm 32 as a unit. Even though the flat rod 24 is tightly secured by rivet 74 it can be swiveled by exerting a twist in order to vary its disposition to accommodate difierent installations.

In lieu of the disc 70 with a cupped flange a plain disc, such as 70, seen in FIG. 3, can be used on the operator rod end of the exemplary actuator, if desired. In an actuator which is spring returned, the diaphragm is never forced up over the outer edge of the backup disc, hence the smaller diameter non-cupped edge of disc 70' will serve very satisfactorily.

The center portion of all forms of diaphragm backup or

support discs

70, 72, 76 and 78, as well as the flat edged disc 70, are made with similar configuration in the area immediately surrounding the rivet aperture. Accordingly, the specific description of that portion of one of the inner discs 76 as shown in FIGS. 4-9 will suffice for all forms. Conventionally, most diaphragm motors use backup plates or discs and the two discs on opposite sides of the diaphragm are fastened together and clamp the inner periphery tight to provide a sealed arrangement. In the clamped arrangement as shown, the inner aperture of the diaphragm engages the fastening rivet and when assembled will press and seal against the rivet. Apertured backup discs with flat surfaces engaging the diaphragm and including the raised annular stiffening rib embossment, such as shown at 86 in FIGS. 4-9, have been used prior to the present invention, in fact such center configuration appears on the backup discs seen in the aforedescribed application. Care must be taken in assembling such discs and diaphragm to assure that the fastening operation does not squeeze the inner portion of the diaphragm away from the rivet. Prior art efforts to avoid the squeezing away of the inner portion of the diaphragm have taught using a raised annular tooth closely adjacent the center aperture on both discs and others have provided complementary annular ribs and grooves in opposing backup discs. Both types can do the job but care must be taken in assembly of both. In one type, too great a clamping force during assembly can cut the diaphragm and in the other, the two discs are different, requiring different manufacturing steps and care in assembling two discs of complementary shape.

In the present invention the backup disc, e.g., disc 76 incorporates a simple structural change. In the exemplary actuator, the raised annular rib 86 ,projecting from the side of the disc 76 which does not contact the diaphragm, has a diameter approximating 0.43 inch and the rivet aperture 88 approximates 0.128 inch diameter. Between the aperture 88 and. the upstanding rib 86 is an annular surface 90 about 0.12 inch in width which presses against the inner portion of the diaphragm. When the sheet metal disc is made, e.g., by a stamping operation in a press, several minute annular grooves 92 (three shown in FIGS. 49) are pressed into the annular diaphragm clamping surface 90 immediate- 1y surrounding the rivet aperture 88. In the discs of the exemplary actuator, the depth of the grooves 92 is approximately 0.007 inch. Thus the inner disc surface 90 has several annular serrations whose primary purpose is to change the flat smooth area around the disc rivet aperture to a surface which engages the rubber diaphragm while the two backup discs and the rivet are being assembled and to help prevent the inner peripheral portion of the diaphragm from pushing radially away from the rivet as it is driven tight enough to deform the diaphragm backup discs adjacent the rivet. This is a very simple and easy expedient and identical configurations of grooved serrations can be used on all of the aforedescribed discs.

LOST MOTION INTERCONNECTION The two

backup discs

72 and 76 which face each other in the intermediate chamber 54 are identical and have integral components which engage and are interlocked with each other to provide a lost motion linkage permitting a very short range of travel of the facing discs toward and away from each other. Disc 76 will be described in detail and similar components on disc 72 will be referenced by the same numerals with prime marks.

The

backup discs

70, 72, 76 and 78 are made from sheet metal, e.g., 21 gage cold rolled steel, and initially all can be made of the configuration seen for disc 70. The

inner discs

72 and 76 undergo additional operations which can be accomplished as separate steps in forming or a special press and tool combination can stamp, punch, pierce and bend a disc blank to the desired configuration of disc 76.

Disc 76 has two integral bent up ears or lugs 98 and 100 punched from the sheet metal disc material constituting the flat platform between the upstanding rib 86 and the outer perimeter flange. The two lugs 98 and 100 are bent to project from the side of the disc which does not contact the diaphragm. One lug 98 is hook shaped while the other lug 100 constitutes an eye. Borrowing a term from the electrical connector art, the disc 76 can be termed as being a hermaphroditic unit, the hook being a male connector and the eye being a female connector.

Eye lug 100 is apertured at 102 to provide a vertical slot whose width is sufficient to freely receive the laterally bent over end portion 104 of hook 98 and permit movement of the hook lug 98 the full length of the eye slot 102. As depicted, the hook lug 98 is disposed closer to the center of the disc, is diametrically opposite the eye lug 100, and its bent over portion 104 extends toward the outer edge of the disc. The terminal end of the bent hook portion 104 includes a small side tab 106. Prior to interconnecting the

discs

72 and 76, side tabs 106 are bent so they are facing the disc to enable the hook lug 98 to be slipped through the eye lug 100. After assembly the tabs 106 are bent slightly outward at an angle to interlock the facing discs, as shown by phantom lines, FIG. 6.

The precise location of the bent up hook lug 98 relative to the bent up eye lug is such that when two discs, 72 and 76, are interconnected, the discs themselves can be aligned along an axis through their rivet aperture although the connection enables sufiicient play for the discs to be skewed relative to each other.

lnterconnection of the

identical discs

72 and 76 is quite simple. Actually each of the two

diaphragms

30 and 32 will be initially assembled. with their respective backup plates and rivets and, in the case of the front diaphragm 32, its operator rod 24. The facing sides of the two diaphragm assemblies; are then brought together with a compression coil. spring between them and seated in the cupped flanges of the

inner discs

72 and 76. The

inner discs

72 and 76 are pressed toward each other against spring bias, held essentially parallel and offset sideways from each along the diametral disposition of the hook and eye lugs 98 and 100. Now, as depicted in FIG. 7, when the hermaphroditic connecting lugs are aligned sideways, the assembled diaphragms and discs are shifted sideways into alignment in the direction of arrows X and Y (FIG. 7), causing the eye 100' to slip over the hook 98 and the hook 98' to slip into the eye 100. Now the connection has been made and to interlock the two facing discs, both of the tabs 106 and 106' can be bent outward about 45 by a tool, such as needle nose pliers.

Assembled with the biasing spring 110 between them, the inner backup discs, as shown in FIG. 1 will be biased away from each other to the limit position permitted by engagement of the hooked lugs 98 and 98' against the bights of the eye lugs 1.00 and 100, respectively. The limit of travel toward each other is determined by abutment of the hooked lugs against the respective bodies of the mated discs as shown in FIG. 3. The collapsible travel is detennined by the lengths of the eye 100 and hook 98. By suitably dimensioning the two components, travel can be made very short, e.g., one-eighth inch, however the exemplary actuator was made to accommodate a one-fourth inch travel limitation between the two diaphragms assemblies.

The cupped outer periphery of disc 76 (FIGS. 5-7) is representative of all four of the

diaphragm discs

70, 72, 76 and 78 and in the case of three: of the discs serve as coil spring seats.

As shown in FIG. 1, the actuator contains two coil compression springs 110 and 112, spring 110 as has been hereinbefore described, being placed between the two diaphragms, seated within the peripheries of the

inner discs

72 and 76 and spring 112 being placed in the rear chamber with one end seated within the cupped periphery of disc 78. The end wall 60 of the housing cup 36 has a frustum shape to provide a spring seat for the other end of rear spring 112.

Spring 110 biases the two

diaphragms

30 and 32 apart with sufiicient force to enable operation, through the operator rod 24, of the unit being operated, e.g., provides a force sufficient to rotate a valve plug (not shown). Similarly, spring 1 12 biases the rear diaphragm 30 away from the rear wall 60 of cup 36 with substantially the same force as provided by spring 110. The spring forces for both springs are chosen so the springs will be readily compressed upon application of vacuum to the respective chambers in which they are disposed.

The collapsible hermaphroditic connection between

inner discs

72 and 76, between

diaphragms

30 and 32, being made from metal, provides a definite limit to the distance which the centers of diaphragms can be spaced apart due to force of the spring 110. The linked connection serves as an articulated connection as well as to delimit a fixed distance between the diaphragm attached end of operator rod 24 and the rear diaphragm 67. Collapse of the lost motion connection is assured to permit the diaphragms to move toward each other, when vacuum is applied to the central chamber 54, at least to the limit permitted by compression of the coil spring 110. The number of coils on spring 110 will determine whether the spring or the collapsible link connection itself determines the collapsed limit positron.

THREE POSITIONS The three positions of the actuator, from which it derives its type designation, are illustrated respectively in FIGS. 1, 2 and 3. Control of application of the vacuum or low pressure source will be via one or more manual or automatic control valves (not shown) as desired for the installation.

FIG. 1 represents the first position, the spring biased extended position of the actuator; in which there is no vacuum applied to either of

connectors

52 or 56, the lines (not shown) which fasten to such connectors being opened to ambient pressure surrounding the actuator itself. Pressures being equalized on both sides of both diaphragms, the bias of spring 110 against the support discs of both diaphragms will force them apart to the limit distance permitted by the

collapsible link connections

98, 100 and 98', 100' and at the same time rear spring 112 will force the rear diaphragms via its support discs toward the cover end of the housing. This combined spring force results in the front diaphragm disc 70 moving to abut against the cover end 'wall 66, at which limit, the attached operator rod 24 is moved out to its fully extended position. The force exerted by the springs to urge the operator rod 24 to its extended position will be selected as desired for a particular installation. While it is preferred that the actuator be a complete bi-directional motor with self contained springs for urging the actuator operating rod in the one direction, the springs could be omitted from inside of the actuator housing, in which event the component being operated could be spring loaded to pull the operator rod 24 to the extended limit position shown in FIG. 1, and vacuum operation of the actuator would work in opposition to the external spring.

FIG. 2 illustrates the No. 2 or intermediate actuator position wherein a source of vacuum has been connected to the rear chamber 58 via connector 56 permitting differential pressure across the rear diaphragm 30 to force that diaphragm toward the rear wall 60 of the cup to its position as limited by compression of the coil spring 112. This movement of diaphragm 30 is transmitted through its

support discs

78 and 76 and the collapsible interconnection between discs 72 and 76 (which will now be fully extended) to pull the front diaphragm 32, through its support discs, toward the rear wall and thereby retract the operator rod 24 to its intermediate position. The vacuum source must provide a pressure differential, relative to ambient pressure, which when applied to the effective pressure area of the diaphragm 30 will exert enough force to overcome the bias of spring 112 and still provide the requisite specified pulling force on the actuator rod 24.

To shift to the No. 3 position shown in FIG. 3, the vacuum source is applied to both the rear chamber 58 and to the middle chamber 54, via

respective connectors

56 and 52. Applying or continuing the connection of vacuum to connector 56 evacuates the rear chamber placing the rear diaphragm 30 in the condition previously described for position No. 2. Evacuation of the middle chamber 54 through the connection 52 causes a pressure differential across the front diaphragm 32 to move it toward the rear diaphragm 30, compressing the coil spring and collapsing the interconnection between

discs

72 and 76 to the compact limit condition as shown in FIG. 3. It should be apparent that the precise location of the No. 3 position can be changed by changing the depth of the cup or by using a different number of coils in spring 112 and that the precise location of the No. 3. position and No. -2 position can be changed by using a different number of coils in spring 110 or by changing the length of the hook and eye lugs on the hermaphroditic

inner discs

72 and 76.

Inasmuch as the present invention is primarily directed to the short travel collapsible interconnection between backup discs of the diaphragms, details of the diaphragms, the spacer rings and cups are not described in detail, although such details are fully disclosed and described in the aforedescribed copending application.

Shown in the FIGS. l-3, both the upper and lower surfaces of spacer ring 44, at the outer peripheral edge of the ring, are provided with annular recesses which, in clamped assembly, cooperate with an annular bead on the outer periphery of the respective diaphragms. This relationship assures that the diaphragms are not only sealingly clamped but are also effectively gripped at its outer periphery to prevent their peripheries from being pulled out from clamped assembly. The spacer ring 44 provides a stable rigid clamping structure which can be satisfactorily accomplished with rings made from metal or plastic. Steel spacer rings are desirable where temperature conditions approximate 265 F. or above whereas plastics have been successful and found to be fully acceptable for environmental temperatures up to 220 F. One plastic material found to be very satisfactory by itself and more so when fiber glass filed is CELCON," an ethyl cellulose thermoplastic.

The diaphragms can be made from rubber or similar materials as required to withstand conditions for various installations. A highly satisfactory oil and temperature resistant material for the diaphragms in actuators used in the automotive field has been found to be a synthetic made from ethylene propylene by Vernay Laboratories, Inc., Yellow Springs, Ohio. It is known to the trade as EPT rubber.

The basic three position actuator can be used without using either of the

internal springs

110 and 112 or an external spring (as was described hereinbefore). Vacuum can be used in lieu of such internal springs and will avoid loss of the built in spring force which must be overcome by the operating vacuum. In such an embodiment, a round rod is used with a shiftable seal arrangement provided between the front chamber wall and the round rod and a vacuum connector is attached to the wall of the front chamber similar to connector 56 as described for the rear chamber. Operating vacuum is then selectively applied to the front chamber as well as to the rear and middle chamber to cause actuator shift from and to all three positions.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. An expansible chamber motor actuator comprising: a housing; two spaced apart movable wall means disposed within said housing dividing the interior of said housing into three chambers; means providing independent fluid communication into each of said three chambers from the exterior of said housing; said movable wall means cooperating with said housing to provide fluid tight isolation between said three chambers; a power transfer link means secured to one of said wall means and projecting from the interior of one end chamber to the exterior of said housing and shiftable in a path generally aligned with the path of movement of said wall means; a collapsible connection means located in the center one of said three chambers between and connected to facing surfaces of both of said movablewall means enabling said movable wall means to move relatively away from and toward each other between a substantially fixed maximum distance between said wall means and a closely adjacent disposi tion, said collapsible connection means located between said movable wall means facing surfaces and constituting a first set of rigid components on and immovable relative to one of said movable wall means and a second set of rigid components on and immovable relative to the other of said movable wall means, said two sets of components being directly interconnected with each other, each of said first and said second sets of rigid components including identical hermaphroditic connector means interconnecting said two sets of components.

2. An actuator as defined in claim 1, wherein biasing means coact with the interconnected assembly of said movable wall means, said collapsible connection means and said power transfer link means urging said wall means in a direction causing maximum extension of said link means out from said housing.

3. An actuator as defined in claim 2, wherein said biasing means comprise expansion coil springs disposed 5. An actuator as defined in claim 4, wherein each of said support plate means on each diaphragm includes a support disc in said center chamber, said two discs being in facing relationship and each including said identical hermaphroditic connector means, interconnecting said two discs.

6. An actuator as defined in claim 4, wherein each of said interconnected support discs includes a hook lug and an eye lug, and wherein each hook lug engages within an eye lug on the facing support disc.

7. An actuator as defined in claim 6 wherein each hook lug includes a bent tab which interlocks said hook lug with its associated eye lug, by being at least partially unbent.

8. An actuator as defined in claim 4, wherein the support plate means for. each diaphragm includes two apertured support discs embracing the apertured central portion of the associated diaphragm; and rivet means, through the apertures, tightly clamp and seal the support discs against the diaphragm; said support discs have annular grooves of minute depth, closely spaced apart, immediately adjacent said disc apertures on the sides of the discs which engage the diaphragm.

9. For use with actuator diaphragms in a plural diaphragm actuator, diaphragm support discs for use on facing sides of adjacent diaphragms, said support discs having identical configurations with each disc including a set of integral, hermaphroditic connector lugs which can interconnect facing support discs to provide a limited travel collapsible link connection between adjacent diaphragms.

10. A diaphragm support disc as defined in claim 9, wherein said disc is made from sheet metal and two spaced apart lugs are bent up from a portion of said sheet metal, one of said lugs being a hook member and the other being an eye member and said hook and eye lugs being disposed so that the hook lug of each one of facing discs can be assembled, by a relative sideways shift of the facing discs, into hooked relationship into the eye lug of the other of each of said discs, thereby providing an interconnected, aligned, collapsible relationship between said two facing discs.

11. A diaphragm support disc as defined in claim 10, wherein each hook lug includes a bend tab which, after assembly, can be bent to provide an interlocking relationship between the hook lug of one disc and the eye lug of an associated disc.

12. A diaphragm support disc as defined in claim 9, wherein the disc is apertured in at least one location to enable passage of a rivet for clamping two discs against the center of a diaphragm, and the surface of said disc which will engage the diaphragm has annular grooves of minute depth, closely spaced apart, in a narrow annular area immediately surrounding said aperture to provide annular diaphragm gripping serrations.

13. A diaphragm support disc as defined in claim 12, wherein said disc is round, a cup flange is provided on its outer periphery, said aperture is centrally located, said lugs are diametrically arranged with the aperture between them, one of said lugs being a hook member and the other being an eye member, and said hook member is slightly closer to the center of said disc than said eye member with its book end projecting toward the outer periphery of the disc.

14. An actuator as defined in claim wherein each said disc with its hermaphroditic connector means thereon comprises a structurally integral unitary piece formed from a stamping of sheet metal material.

UNITED semi-3s OFFICE .V o CERTIFICATE 3F CQRRECTION Dated August 15, 1972 Patent No.

lnv Jesse R. Johnson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby correcteci as shown below:

Please correct line [22] on the cover page of the above patent to reflect the correct filing date of ---February 9, l 970-;.

Signed and sealed this 1st day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JRu (3.. MARSHALL DANN Attesting Officer Commissioner of Patents 'oRM 1 0-1050 (10-69) USCOMM-DC GOING-P69 0.5. covnnmm rmmmcorncc: HM o-uu-au

Claims

1. An expansible chamber motor actuator comprising: a housing; two spaced apart movable wall means disposed within said housing dividing the interior of said housing into three chambers; means providing independent fluid communication into each of said three chambers from the exterior of said housing; said movable wall means cooperating with said housing to provide fluid tight isolation between said three chambers; a power transfer link means secured to one of said wall means and projecting from the interior of one end chamber to the exterior of said housing and shiftable in a path generally aligned with the path of movement of said wall means; a collapsible connection means located in the center one of said three chambers between and connected to facing surfaces of both of said movable wall means enabling said movable wall means to move relatively away from and toward each other between a substantially fixed maximum distance between said wall means and a closely adjacent disposition, said collapsible connection means located between said movable wall means facing surfaces and constituting a first set of rigid components on and immovable relative to one of said movable wall means and a second set of rigid components on and immovable relative to the other of said movable wall means, said two sets of components being directly interconnected with each other, each of said first and said second sets of rigid components including identical hermaphroditic connector means interconnecting said two sets of components.

3. An actuator as defined in claim 2, wherein said biasing means comprise expansion coil springs disposed in two of said chambers which together urge said movable wall means toward a minimum volume condition of the remaining chamber.

4. An actuator as defined in claim 1, wherein said movable wall means include diaphragms with diaphragm support plate means secured to each of said diaphragms, and wherein said collapsible connection means constitute integral parts of said diaphragm support plate means on facing sides of said two movable wall means.

5. An actuator as defined in claim 4, wherein each of said support plate means on each diaphragm includes a support disc in said center chamber, said two discs being in facing relationship and each including said identical hermaphroditic connector means, interconnecting said two discs.

8. An actuator as defined in claim 4, wherein the support plate means for each diaphragm includes two apertured support discs embracing the apertured central portion of the associated diaphragm; and rivet means, through the apertures, tightly clamp and seal the support discs against the diaphragm; said support discs have annular grooves of minute depth, closely spaced apart, immediately adjacent said disc apertures on the sides of the discs which engage the diaphragm.

13. A diaphragm support disc as defined in claim 12, wherein said disc is round, a cup flange is provided on its outer periphery, said aperture is centrally located, said lugs are diametrically arranged with the aperture between them, one of said lugs being a hook member and the other being an eye member, and said hook member is slightly closer to the center of said disc than said eye member with its hook end projecting toward the outer periphery of the disc.

14. An actuator as defined in claim 5 wherein each said disc with its hermaphroditic connector means thereon comprises a structurally integral unitary piece formed from a stamping of sheet metal material.