US3304385A

US3304385A - Pneumatic actuator with folded diaphragm

Info

Publication number: US3304385A
Application number: US373928A
Authority: US
Inventors: Harald E Vollbehr
Original assignee: Robertshaw Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1964-06-10
Filing date: 1964-06-10
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14

Description

14, 1967 H. E. VOLLBEHR PNEUMATIC ACTUATOR WITH FOLDED DIAPHRAGM Filed June 10, 1964 FIG.3

' INVENTOR. HARALD E. VOLLBEHR HIS ATTORNEYS United States Patent ()fifice 3,304,385 PNEUMATIC ACTUATUR WITH FQLDED DIAPHRAGM Harald E. Vollhehr, Irwin, Pan, assignor to Rohertshaw Controls Company, Richmond, Va., a corporation of Delaware Fiierl June 10, 1964. Ser. No. 373,528 Claims. or. zen-as This invention relates to an improved pneumatic actuatoror the like.

It is well known that various actuators have been provided in the past for controlling movement of a desired device when a pneumatic signal is imposed on the actuator.

' Forexample, pneumatic operated actuators have been provided wherein a flexible diaphragm of the actuator is moved between its actuating positions by having the chamber thereof either interconnected to a pressure source or to a vacuum source.

I According to the teachings of this invention, an improved actuator of the above type is provided which has many features not present in the prior known actuators.

Accordingly, it is an object of this invention to provide an improved pneumatic actuator having one or more of the novel features set forth above or hereinafter shown or described.

A Other objects, uses and advantages of this invention are apparent from a reading of this description, which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIG. 1 is a side view, partially in cross section, illustrating the improved pneumatic actuator of this invention in combination with an electrical switch or the like.

FIGURE 2 is a view similar to FIGURE 1 and illustrates the actuator in another operating position thereof.

FIGURE 3 is an exploded perspective view illustrating the various parts of the actuator of FIGURE 1.

FIGURE 4 is a fragmentary, perspective view illustrating how the actuator post of FIGURE 1 is interconnected to the switch blades of the electrical switch of FIGURE 1.

While the various features of this invention are hereinafter'described and illustrated as being particularly adaptable to provide a pneumatic actuator, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide other devices as desired. -Therefore,-this invention is not to be limited to only the embodiments illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGURE 1, the improved pneumatic actuator of this invention is generally indicated by the reference numeral and comprises a substantially rigid cup-shaped housing 11 having a flexible diaphragm 12 secured thereto in a manner hereinafter described and cooperating therewith to define a chamber 13 in the actuator 10.

The flexible diaphragm 12 carries an actuating post or member 14 adapted to move in unison with the flexible diaphragm 12 to actuate the desired structure.

For example, the actuator post 14 illustrated in FIG- URES 1 and 2 is interconnected to a plurality of flexible switch blades 15, 16 and 17 carried by an electrical switching device 18, the electrical switching device 18 and pneumatic actuator 10 being interconnected together by a mounting bracket 19 in any suitable manner.

The switch blades 15, 16 and 17 respectively carry

electrical contacts

20, 21 and 22 normally disposed in electrical contact with

contacts

23, 24 and 25 when the 3,3ii4,385 Patented Feb. 14, I96? actuator 16 is in its non-actuated or normal position, as illustrated in FIGURE 1, the

contacts

23, 24 and 25 being respectively carried on substantially

rigid switch blades

25, 27 and 28.

However, when the actuator 10 has a pneumatic signal imposed thereon in the manner illustrated in FIGURE 2, the

contacts

20, 21 and 22 are moved out of contact with the

contacts

23, 24 and 25 and moved into contact with

contacts

29, 25 and 30, the

contacts

29 and 30 being carried on substantially

rigid switch blades

31 and 32.

Thus, it can be seen that the pneumatic actuator 10 is adapted to control the switching mechanism 18 as the same moves between the positions illustrated in FIG- URES 1 and 2.

The details of the pneumatic actuator 15) of this invention will now be described.

As illustrated in the drawings, the cup-shaped housing 11 has an outwardly directed annular flange 33 surrounding the open end thereof, the flange 33 having a substantially rectangular cross-sectional configuration defining opposed side edges 34 and 35 thereof.

The housing member 11 has a hollow tubular extension 36 projecting outwardly and centrally from the closed wall thereof, whereby the housing member 11 can be sealably attached to a flexible conduit 37 telescoped over the tubular extension 36, the conduit 37 being adapted to selectively interconnect a vacuum source with the chamber 13 of the actuator 19 by means of the passage means 38 formed in the tubular extension 36 of the housing 11.

An annular flange 39 surrounds the tubular extension 35 of the housing 11 and is adapted to be fastened 'to the mounting bracket 19 in any suitable manner.

The flexible diaphragm 12 has a body portion 40 integrally interconnected to an annular peripheral flange 41 internally interrupted by a recess or groove 42 which defines

opposed portions

43 and 44 of the flange 41.

The flexible diaphragm 12 is adapted to have the peripheral flange 41 thereof snap-fitted over the annular flange 33 of the cup-shaped housing member 11 in the manner illustrated in FIGURES 1 and 2 whereby not only is the annular flange 41 radially press-fitted on the flange 33 of the housing 11, but also the

opposed portions

43 and 44 of the flange 41 compress against the side edges 34 and 35 of the flange 41 of the housing 11.

In this manner, the annular flange 41 of the flexible diaphragm 12 is completely snap-fitted and press-fitted on the annular flange 33 of the housing member 11 to provide a fluid seal therebetween.

The body portion 49 of the flexible diaphragm 12 has an aperture 45 passing centrally therethrough, the aperture 45 being surrounded by an outwardly directed annular flange 46 formed integrally with the diaphragm 12.

The actuator post 14 is integrally connected to a flat circular disc or plate-like member 47 adapted to be disposed in the chamber 13 of the actuator 10 and have one side 48 thereof disposed against the under side 49 of the diaphragm 12 in the manner illustrated in FIGURE 1, the plate-like member 47 being interconnected to the post 14 adjacent an annular recess 50 provided in the post structure 14.

In this manner, the post 14 can be press-fitted through the aperture 45 of the diaphragm 12 until the plate-like member 47 abuts against the side 49 of the diaphragm 12 and the annular flange 46 of the diaphragm 12 is pressfitted into the recess 50 of the post 14 whereby the aperture means 45 is completely sealed by the press fit relationship of the annular flange 46 in the recess 50 of the post 14, the annular flange 46 not only being in the radial compression around the post 14 at the recess 50 but C also being under compression between the post 14 and the plate-like member 47.

Thus, it can be seen that the chamber 13 of the actuator is completely sealed from the atmosphere because of the sealing relationship between the diaphragm 12 and the housing 11 and post 14.

The post 14 has a plurality of

annular recesses

51, 52 and 53 formed therein in order to provide lost motion means for interconnecting the post 14 to the switch blades 15, 16 and 17 in the manner fully illustrated in FIGURE 4, each blade -17 having a slot 54 provided therein at the end thereof so that the reduced portion of the post 14 can be received in the slot 54.

Thus, it can be seen that when a vacuum source is interconnected to the chamber 13 of the actuator 10, the diaphragm 12 is forced downwardly to the positon illustrated in FIGURE 2 by the air pressure surrounding the diaphragm 12 whereby the actuating post 14 moves the switch blades 1517 downwardly to operate the switching mechanism 18 in the manner illustrated in FIGURE 2. However, when the vacuum source is disconnected from the chamber 13 and the chamber 13 is permitted to return to normal atmospheric conditions, the diaphragm 12 moves upwardly to the position illustrated in FIGURE 1 to operate the switching mechanism 18 in the manner illustrated in FIGURE 1, the diaphragm 12 being moved upwardly either by the natural resiliency of the diaphragm 12 and/ or by the natural tendency of the switch blades 15-17 to move upwardly t0 the position illustrated in FIGURE 1.

Thus, it can be seen that during the movement of the diaphragm 12 between the positions illustrated in FIG- URES 1 and 2, the plate-like member 47 of the actuating post 14 is firmly held against the body portion 40 of the diaphragm 12 to provide suflicient back-up means therefor.

Accordingly, it can be seen that not only does this invention provide an improved pneumatic actuator, but also this invention provides an improved combination wherein the pneumatic actuator is adapted to control the desired device.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. In combination, a switch mounting block means, a plurality of contact carrying switch blades being carried by said block means in stacked relation, certain of said blades being resilient and having slotted free ends, a pneumatic actuator interconnected to said block means and having a rigid housing member provided with an outwardly directed annular flange, a flexible diaphragm having a body portion and an annular flange offset relative to said body portion, said flange of said diaphragm having an inwardly facing groove snap-fitted over said flange of said housing member whereby said flange of said diaphragm is under both radial and axial compression on said flange of said housing member to effect a positive fluid seal therewith, said body portion and said flange being so constructed and arranged that said body portion is not placed under radial tension by the snap-fitting of said diaphragm flange over said flange of said housing member whereby said snap fitting does not impose retarding forces on movement of said body portion of said diaphragm between the operating positions of said actuator, and an actuating post carried by said body portion of said diaphragm, said post having a plurality of spaced annular recesses provided therein and respectively defining reduced portions of said post, said reduced portions of said post respectively being received in said slots of said certain switch blades and providing lost motion means therewith whereby movement of said body portion of said diaphragm from one position thereof to another position thereof moves said certain switch blades out of contact with certain other blades and into contact with the remainder of said blades.

2. A combination as set forth in claim 1 wherein said body portion of said diaphragm folds upon itself when said body portion is in one of its operating positions.

3. A combination as set forth in claim 1 wherein said rigid housing member of said actuator is substantially cup-shaped and has said annular flange thereof at the open end of said cup shape;

4. A combination as set forth in claim 1 wherein said actuating p o-st carries a back-up plate disposed against the inside surface of said body portion of said diaphragm, said body portion of said diaphragm having an opening passing therethrough and receiving said actuating post, said post having an annular recess means therein adjacent said back-up plate, said diaphragm having an outwardly directed annular flange coaxial with said opening thereof, said annular flange being received in said recess means and being under both axial and radial compression in said recess of said post to elfect a positive fluid' seal therewith.

5. A combination as set forth in claim 4 wherein said back-up plate and said post are integral.

References Cited by the Examiner UNITED STATES PATENTS 1,954,563 4/ 1934 Malaussene; 2,049,531 8/1936 White 200-83 2,715,946 8/1955 Peterson 20083 X 2,814,704 11/1957 Bald. 2,984,726 5/ 1961 Roeser. 3,049,603 8/1962 Flatt et al. 200 -83 3,066,698 12/1962 Siri 200-83 X 3,125,702 3/1964 Herridge et al. 200'83 X BERNARD A. GILHEANY, Primary Examiner.

H. M. FLECK, G. MAIER, Assistant Examiners.