US2912993A

US2912993A - Motion transmitting mechanism for air transmitter

Info

Publication number: US2912993A
Application number: US741756A
Authority: US
Inventors: Jones Barton
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-06-13
Filing date: 1958-06-13
Publication date: 1959-11-17
Anticipated expiration: 1976-11-17

Description

MOTION TRANSMITTING MECHANISM FOR AIR TRANSMITTER FilQd June 13, 1958 B. JONES Nov, ii 7, 1959 2 Sheets-Sheet 1 1 Q r 5 9. v i 5 4 H 2 Q M W 56 I 45 45 INVENTOR. 5 mew/v JONES mam/6V5" Fza. j."

B. JONES 2 Sheets-Sheet 2 Nov. 17,1959

MOTION TRANSMITTING MECHANISM FOR AIR TRANSMITTER Filed June 13, 1958 United States Patent MOTION TRANSMITTING MECHANISM FOR AIR TRANSMITTER Barton Jones, Monterey Park, Calif. Application June '13, 1958, Serial No. 741,756

7 8 Claims. (Cl. 137-85) This invention relates to improvements in motion transmitting mechanisms for air transmitters. The application is a continuation-in-part of my copending application Serial No. 530,477, filed August 25, 1955, now Patent No. 2,842,148.

Explanatory of the present invention, there have here: tofore been designed air transmitters wherein a relay valve that is supplied with air under pressure is actuated by the back pressure developed by a flapper engageable with a nozzle through which air from the source of supply escapes after passing through a restricter. When the flapper is lifted from the nozzle to permit air to be discharged through the nozzle more freely there is a minimum of back pressure. This reduction in back pressure is effective to cause the relay valve to close and to cause the pressure of the transmitted air to be reduced by releasing it to atmosphere. Conversely, when the flapper closes against the nozzle back pressure developed in the nozzle quickly builds up causing the relay valve to open and thus release a greater amount of compressed air from the source of supply so that it may be transmitted to the receiver. The flapper is actuated by means of a driver or an exciter which is moved by a suitable mechanism and the function of the air transmitter is to transmit air pressure to a receiver at a pressure which will bear a direct relationship to the movements of thedriver or exciter.

It has been proposed to fulcrum the flapper on a repositioning bellows which is subject to and is influenced by the pressure of the transmitted air. The purpose of this is so that in all positions of the exciter or driver the flapper is in a position to be immediately depressed or released thereby for movement towards or away from the nozzle. In this manner, if the exciter or driver is in a position requiring the transmission of air at one pressure and shifts slightly to require the air that is transmitted to be at a lower pressure the flapper will be maintained at all times in a position so as to be instantly influenced thereby. Likewise, if the exciter or driver shifts slightly to require that the air that is transmitted to be at a higher pressure the flapper will be maintained at all times in a position with relation to the nozzle so as to be instantly influenced thereby,

Very frequently the mechanism which actuates the exciter or driver is in the form of a differential pressure responsive device of the type disclosed in my United States Letters Patent No. 2,400,048, issued May 7, 1946, wherein there are two opposed metallic bellows which are subjected to the pressures between which a differential may exist. A torque tube or equivalent device transmits the motion of these bellows to the exterior of the device and this torque tube may constitute the driver or exciter of the present invention.

The metallic bellows of the differential pressure responsive device and also the metallic bellows of the air transmitter are not always linear in their movements in response to the pressures to which they may be subjected. In some instances the effect of the bellows is such that they may have a combined effect that may be regarded 2,912,993 Patented Nov. 17, 1959 as a plus error wherein the movements of the bellows are greater than the movements which they should have in response to the pressures to which they are subjected. In other instances, the bellows may have a combined effect of what may be regarded as a minus error wherein the movements of the bellows are actually less than the movements that they should have in response to the pressures to which they are subjected.

A primary object of the present invention is to provide a very simple and readily adjustable mechanism of the linkage train between the torque tube or exciter and the flapper which will enable these errors, if they exist, to be easily corrected and compensated for. Consequently, regardless of what type of error the bellows may have with respect to their pressures, if in fact such error exists,

the movement of the flapper may be made to conform to the pressures which are intended to actuate it. Thus, a plus error, if it exists, may be corrected or neutralized, and likewise a minus error, if it exists, may be corrected or neutralized. If the bellows either inherent-1y have no error or the combined errors of the various bellows neu tralize each other the linkage train may be so adjusted that no correction or compensation is made.

More specifically, an object of the invention is to provide means for fulcruming the flapper of an air transmitter on the re-positioning bellows of the air transmitter so that the fulcruming means is movable along the length of the flapper toward and away from the nozzle and the fulcrum-providing portion thereof is swingable about an axis remote from thepoint where it fulcrums the flapper and is confined to a swinging movement about said axis. This axis while normally stationary, is adjustable so that by means of its adjustment a plus error, if it exists, can

be corrected or neutralized and likewise a minus error, if

it exists, may be corrected or neutralized, or if the bellows either inherently have no error or the combined errors of the combined bellows neutralize each other, the linkage train may be so adjusted that no correction or compensation is made.

Still another object of the invention is to provide a construction having the above-mentiond characteristics wherein the fulcruming-providing means, instead of being slidable between the re-positioning bellows and the flapper, is mounted on the re-positioning bellows for universal movement relatively thereto, thus reducing any tendency of parts to bind. In accordance with the present construction the re-positioning bellows preferably has its stationary end anchored at a point most adjacent the flapper and the movable end of the re-positioning bellows is located more remote therefrom. While the adjust-.

ment of the fulcruming means to compensate for plus error or minus error may cause it to assume positions that depart slightly from an exact co-axial position of the bellows, by reason of the. fact that the re-positioning bellows is in effect suspended rather than supported and the departures of the fulcruming means from truly coaxial positions are usually small, this arrangement is such as Figure 1 is a sectional view of an air transmitter illus- I trating the motion transmitting mechanism embodying the present invention as having been applied thereto;

Fig. 2 is a partial view in horizontal section taken substantially upon the line 22 upon Fig. 1 in the direction indicated;

Fig. 3 is a partial view in vertical section taken substantially upon the line 3--3 upon Fig. 1 in the direction indicated; and

Fig. 4 illustrates positions assumed by parts at one extreme of one adjustment.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the transmitter illustrated on Fig. 1 is generally similar in construction to the construction disclosed in my United States Letters Patent No. 2,718,896, and consists of a base 14 to which compressed air is supplied from a source of supply through an inlet port 11. The compressed air after passing through a filter 12 retained in place by a removable nut 13, passes into a valve chamber 14. A portion of the air supplied to the valve chamber 14 is conducted through a passage 15, see Fig. 3, to a restricter 16. After passing through the restricter this portion of the air is conducted by means of

passages

17 and 18 to the interior of a lower bellows 19 which is mounted on the underside of a horizontal partition plate 20.

Within the bellows 19 there is an inner bellows 21 which is also mounted on the underside of the partition plate 20 and the lower ends of both bellows are connected together to a rigid connecting stem 22. The air that is conducted from the restricter 16 through

passages

17 and 18 is discharged into the space between the two bellows and from this space it finds egress through

passages

23 and 24 to a nozzle 25 through which air is more or less continuously discharged. The nozzle 25 is threadedly mounted for vertical adjustment on a nozzle holder 26.

On the upper side of the partition plate 20 there are two bellows, the outer bellows being indicated at 27 and the inner bellows being indicated at 28. The upper ends of both bellows are connected together and to the upper end of the rigidconnecting stem 22. The etfective areas of the

outer bellows

19 and 27 are'equal to each other, and in a similar'manner, the efiective areas of the

inner bellows

21 and 28 are equal to each other. The stem 22 being a rigid stem, causes the outer or movable ends of all of the

bellows

19, 21, 27, and 28 to move vertically in unison. The space between the

upper bellows

27 and 28 is connected through

passages

29 and 30 to an upper housing, generally indicated at 31, and to atmosphere through an outlet port 32 therein.

Within the stem 22 there is a valve seat 33 on which a valve closure 34 is adapted to .seat. This valve closure has a stem 35 on which a valve closure 36 is adjustably mounted such as by being threaded thereon and locked in adjusted position by means of a locknut 37. The lower valve closure 36 is adapted to seat on a seat 38 arranged at the top of chamber 14. In the stem 22 there is a transversely extending bore or passage 39 which is located above the valve seat 33 and which discharges into the interior of the inner bellowss 21 when the closure 34 is open or in unseated position. From the inner bellows 21 air that is allowed to escape from chamber 40 when closure 34 is opened or unseated may find egress through

passages

29 and 30 to atmosphere at 32. 41 indicates the outlet which is connected to chamber 40 through a filter 42 and a passage 43. A filter is preferably employed at this point due to the fact that under certain conditions there may be a tendency toward back flow from the receiver to the chamber 40.

It will be appreciated from the above described construction that if flow of air through the nozzle 25 is retarded or restricted that the back pressure developed by such a restriction is effective on the

bellows

19 and 21 to urge these bellows to expand. When these bellows xpand downwardly they'cause the seat 33 to engage the closure 34, thus closing the chamber 49 against the escape of air. The closure 36 may be unseated under these circumstances, allowing compressed air from the inlet 11 to enter the chamber 49 and to pass therefrom to the outlet 41 and thence to the receiver. The upper bellows 27 is externally subjected to whatever pressure exists in the chamber 40, passages 44 in the partition 20 providing free communication between the top and bottom of the chamber through the partition plate. It air is allowedto escape more freely through the nozzle 25 the back pressure that is effective on the

bellows

19 and 21 is reduced and these bellows are consequently permitted to contract. When these bellows contract the stem 22 is lifted'so that the closure 36 may be seated by virtueof the compression spring 45. The valve seat 33 may be lifted above the closure 34 and air in the chamber 40 may consequently be allowed to escape to atmosphere through

passages

39, 29, 3t), and 32. This escape of air from the chamber 40 reduces the pressure of the air that is transmitted to the receiver through the outlet 41. It will thus be understood that if egress of air through the nozzle 25 is retarded, that the pressure transmitted through the outlet 41 to the receiver will be increased, and conversely, if the restriction on the nozzle 25 is reduced, the pressure of air transmitted to the receiver through outlet 41 will be decreased.

On top of the chamber 40 there is mounted a re-positioning bellows 50, the exterior of which is subject to whatever pressure exists in the top of chamber 40. The interior of the re-positioning bellows 50 is subjected merely to atmospheric pressure from port 32. This repositioning bellows has its stationary end secured to a cap 51 and'its movable end secured to a plate 52 that is fastened'to a disc or plate 53 by means of a bolt 54. The plate-or disc 53 serves as a spring seat for a compression spring 55. In this arrangement it will be observed that'the re-positioning bellows has its upper end stationary and its lower end movable, movement of the bellows '50 being largely in response to the pressure in the chamber 40.

The head of the bolt 54 is coned out or countersunk as at 56";to pro'videa seat for a ball 57 at the bottom of a stem 58. A thin metal pin 59 is threaded for adjustment onto the stem 58 and extends through a slot 60 that extends longitudinally of the flapper 61. A fulcrum pin 62extends through the pin 59 and bears against the underside of the flapper 61 and serves to fulcrum the flapper intermediate its ends on the top of stem 58 which, in turn, is supported by its ball 57 on the lower and movable end of the re-positioning bellows 50. The end of the flapper 61 that is remote from nozzle 25 is connected to an arm 63 on a crank 64 that is on an exciter or driver shaft 65. This driver shaft or exciter may be oscillated by any suitable mechanism such as for exam ple a diiferential pressure responsive means of the type disclosed in my prior United States Letters Patent No. 2,400,048. The connection between the flapper and the arm 63 may be in the form of merely a flexible section of sheet metal 66 which forms a type of hinge connection connecting the arm 63 with the flapper. When the exciting or driving shaft 65 turns in one direction it is eflective to depress the end of the flapper 61, causing it to fulcrum on the fulcrum pin 62 and to be elevated with respect to the nozzle 25. Conversely, if the exciting or driving shaft 65 rotates in the opposite direction arm 63 is elevated and flapper 61 is fulcrumed on the fulcrum pin 62 to approach the nozzle 25 more closely.

As above explained, the action of the various bellows frequently is not linear and the combined actions of all of the bellows may result in either a plus error or minus error, or no error at all. To compensate for these errors the fulcrum pin 62 is located on the end of an arm 67 which,-in turn, has a parallel pin 68 that is parallel to the fulcrum pin 62. Pin 68 is rotatably mounted on a bracket 69 that is rotatably adjustable by means of a screw 7th on a plate 71. The plate 71 is transversely adjustable with relation to a supporting boss 72 on loosening a screw 73 that extends through a slot 74 in the plate. Fine adjustment of this plate in a transverse direction is accomplished by means of an adjusting screw 75.

It will be appreciated by the above-described construction that lateral adjustment of plate 71 produces a lateral adjustment of fulcrum pin 62 and that this varies the two arms of the flapper 61 considering this flapper as a simple lever. Thus, the distance between the fulcrum pin 62 and arm 63 and the distance between fulcrum pin 62 and nozzle 25 can be varied by adjusting the lateral position of plate 71 and consequently the position of the fulcrum pin 62. Consequently, calibration, particularly the range of calibration, can be easily accomplished by merely adjusting the position of plate 71.

With the arrangement above described, it will be appreciated that fulcrum pin 62, in the course of its upward and downward movement, is caused to swing about the axis of pin 68 as a center which is remote from the point at which fulcrum pin 62 fulcrums the flapper 61. Thus, in the position shown in Fig. 1, if the re-positioning bellows is expanded, causing stem 58 to descend, the fulcrum pin 62 swings through an arc whose center is the axis of pin 68 which in the position shown, is remote from the point of fulcruming of the flapper 61 and below and to the right thereof. This position of bracket 69 causes one type of error to be compensated for in that as the fulcrum pin 62 is caused to swing about pin 68 as a center it will slide or move toward the left on the underside of the flapper as the stem 58 descends, thus increasing the lever arm between the fulcrum pin 62 and arm 63, and decrease the lever arm between fulcrum pin 62 and nozzle 25.

If screw 70 is loosened and bracket 69 is adjusted to position pin 68 above and to the right of fulcrum pin 62, the opposite relationship will occur. That is, as the stem 58 descends, fulcrum pin 62 being confined to a swinging movement about 68 as a center, will be caused to slide or move on the underside of flapper 61 toward the right, thus shortening the lever arm between fulcrum pin 62 and arm 63 and increasing the lever arm between fulcrum pin 62 and nozzle 25. If the bracket 69 is so adjusted that axis of pin 68 is approximately coincident with the plane of flapper 61, then virtually no compensation is made for the bellows. This position may be adopted when the bellows either have no errors to be corrected or their errors mutually neutralize each other.

Adjustment of bracket 69 with relation to screw 70 when the screw is loosened occurs about an axis that is parallel with the axis of fulcrum pin 62 and with the axis of the exciting or driver shaft. By virtue of the fact that the stem 58 is equipped with a ball 57 seated on the bolt 54 on the lower end of the re-positioning bellows, the stem has a universal movement with respect to the repositioning bellows, thus reducing any tendency of the stem and its associated structure to bind. Although the position of the stem may depart from a position that is true coaxial with the re-positioning bellows illustrated in Fig. 1, the departure being indicated in Fig. 4, this departure is not great and as the re-positioning bellows has its stationary end most adjacent the flapper and its movable end most remote thereof, and is consequently virtually suspended from cap 51, the departures of the stem 58 are such as not to objectionably distort or abnormally load the re-positioning bellows even though plate 71 and bracket 69 are severely adjusted in order to compensate for errors inherent in the bellows.

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. In an air transmitter, an exciting crank arm, a nozzle, and a flapper therefor, a re-positioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the re-positioning bellows pivotally mounted on the re-positioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being movable along the length of the flapper and swingable about an axis remote from the point where it ful- 6 crums the flapper, and means confining its movements along the length of the flapper to a swinging movement about said axis.

2. In an air transmitter, an exciting crank arm, a nozzle, and a flapper therefor, a re-positioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the re-positioning bellows pivotally mounted on the re-positioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being movable along the length of the flapper and swingable about an axis remote from the point where it fulcrums the flapper, means confining its movements along the length of the flapper to a swinging movement about said axis, and means for adjusting the position of the axis about which the fulcruming means is swingable.

3. In an air transmitter, an exciting crank arm, a nozzle, and a flapper therefor, a re-positioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the re-positioning bellows pivotally mounted on the re-positioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being movable along the length of the flapper and swingable about an axis remote from the point where it fulcrums the flapper, means confining its movements along the length of the flapper to a swinging movement about said axis, and means for adjusting the position of the axis about which the fulcruming means is swingable through an arc the axis of which is parallel with the axis about which the fulcruming means fulcrums the flapper.

4. In an air transmitter, an exciting crank arm, a nozzle, and a flapper therefor, a re-positioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the re-positioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being movable along the length of the flapper and swingable about an axis remote from the point where it fulcrums the flapper, means confining its movements along the length of the flapper to a swinging movement about said axis, and means for adjusting the position of the axis about which the fulcruming means swingable through an arc, the axis of which is parallel with the axis of rotation of the exciting crank arm.

5. In an air transmitter, an exciting crank arm, a nozzle and flapper therefor, a re-positioning bellows subjected to the transmitted pressure, a fulcruming means for the flapper mounted on the re-positioning bellows for universal movement relatively thereto, means connecting the flapper to the exciting crank arm, the fulcruming portion of said fulcruming means being movable along the length of the flapper toward and away from the nozzle and being swingable about an axis remote from the point where it fulcrums the flapper, and means confining the swinging movement of the fulcruming portion to an are about said axis.

6. In an air transmitter, an exciting crank arm, a nozzle and flapper therefor, a re-positioning bellows subjected to the transmitted pressure, a fulcruming means for the flapper mounted on the re-positioning bellows for universal movement relatively thereto, means connecting the flapper to the exciting crank arm, the fulcruming portion of said fulcruming means being movable along the length of the flapper toward and away from the nozzle and being swingable about an axis remote from the point where it fulcrums the flapper, means confining the swing ing movement of the fulcruming portion to an arc about said axis, and means for adjusting the position of the axis about which the fulcruming means is swingable.

7. In an air transmitter, an exciting arm, a nozzle and flapper therefor, a re-positioning bellows subjected to the transmitted pressure, said re-positioning bellows having its anchored end most adjacent the flapper and its movable end remote therefrom, a stem mounted for universal movement on the movable end of the re positioning bellows and having a fulcruming portion engageable with the flapper intermediate the exciting crank "7 arm and the nozzle, said fulcruming portion being movable along the length of theflapper, and means restricting movements of the fulcrurning portion of the stem to movements through an arc, the axis of which 'is remote from the point where it tfulcrums the flapper.

8. In an air transmitter, an exciting arm, a nozzle and flapper therefor, a re-positioning bellows subjected to the transmitted pressure, said re-positioning bellows having its anchored end most adjacent the flapper and its movable and remote therefrom, a stem mounted for universal movement on the movable end of the repositioning bellows and having a fulcruming'portion engageable with the flapper intermediate the exciting crank arm and the nozzle, said fulcruming portion being movable along the length of the flapper, means restricting movements 15 2,842,148

of the fulcruming portion of the stem to movements through an arc, the axis of which is remote from the point .:where it fulcrums the flapper, and means for adjusting said axis in a direction parallel to the length of the flapper and through an arc, the axis of which is parallel with the axis about which the flapper is' fulcrumed.

UNITED STATES PATENTS 2,632,456 Breedlove Mar. 24, 1953 2,675,826 Kehoe Apr. 20, 1954 2,718,896 Jones Sept. 27, 1955 Jones July 8, 1958