US3247932A

US3247932A - Time delay device

Info

Publication number: US3247932A
Application number: US380520A
Authority: US
Inventors: William H South
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1964-07-06
Filing date: 1964-07-06
Publication date: 1966-04-26
Anticipated expiration: 1983-04-26

Description

TIME DELAY DEVICE Filed July 6, 1964 2 Sheets-Sheet 1 FIG. I.

FIG. 2.

FIG. 3.

WITNESSES: INVENTOR 72 William H. South BY !QQ g ;t ATZ RNEY April 26, 1966 w. H. SOUTH 3,247,932

TIME DELAY DEVICE Filed July 6, 1964 2 Sheets-Sheet 2 United States Patent Ofiice 3,247,932 Patented Apr. 26, 196% 3,247,932 TEME DELAY DEVICE William H. South, McKeesport, lPa., assignor to Westinghouse Electric (Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed July 6, 1964, Ser. No. 380,520 13 Claims. (Cl. 188-94) This invention relates to time delay devices and, more specifically, to valve means particularly adapted for such devices. g

In certain types of control equipment, time delay devices of the fluid dashpot type are employed which include a tapered-needle type valve. In a device of the latter type, the amount of time delay is commonly varied by adjusting the position of a needle relative to an associated valve seat to vary the size of an annular orifice through which a fluid flows during the operation of the device. A- time delay device of the above type has several disadvantages. For example, the relationship between the amount of time delay provided by the device and the needle valve travel is not linear. In other words, for each setting of the needle valve, a diflerent rate of change of time delay results as the position of the needle valve is varied. In addition, the parts of a needle valve employed in a time delay device of the above type must be relatively precisely shaped and dimensioned during manufacture in order to obtain a reasonably satisfactory operation of the time delay device. A time delay device employing a needle type valve has the further disadvantage that any lost motion between the needle adjusting device, the needle guiding means and the valve seat results in certain inaccuracies in the setting of the valve opening. It is therefore desirable to provide an improved time delay device including an improved valve means which is particularly adapted to such devices which overcomes the above disadvantages of a conventional time delay device and which offers certain other advantages.

It is an object of this invention to provide a new and improved time delay device.

Another object of this invention is to provide an improved valve means which is particularly adapted for use in time delay devices.

A further object of this invention is to provide an improved time delay device in which the relationship between the amount of time delay provided and the adjustment of the valve means indicated in the device is substantially linear.

Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a top plan view of a time delay device embodying the principles of the invention;

FIG. 2 is a partial bottom view, partly in section and partly cut away, of the time delay device shown in FIG. 1;

FIG. 3 is a side elevational view, in section, of the time delay device shown in FIG. 1 with certain portions of associated equipment shown in phantom;

FIG. 4 is a partial side elevational view of a time delay device illustrating a second embodiment of the invention;

FIG. 5 is a partial bottom view, partly in section and partly cut away, of the time delay device, shown in FIG. 4; and

FIG. 6 is a partial side elevational view, in section, illustrating a third embodiment of the invention.

Referring now to the drawings and FIGS. 1 through 3 in particular, the time delay device 10 comprises a flexible diaphragm 32 which is attached to the lower end of a stem or shaft 38 and a valve means 26 for admitting air or other fluid to the space below the diaphragm 32 at various rates to provide different durations of time delay in the operation of the associated equipment indicated at 53 in FIG. 3, which may operatively be connected to the reduced portion of the shaft 33 below the flange portion 220i the shaft 38. The member 53 may form part of an electromagnetic tripping means, as disclosed in detail in copending application Serial No. 380,276, filed concurrently by Joseph D. Findley and William H. South and assigned to the same assignee as the present application. The flexible diaphragm 32 may be formed from a suitable material, such as a fabric reinforced neoprene rubber and is disposed in a chamber 4%) formed in an upper housing member 42 and a lower housing member 36. Both of the

housing members

42 and 36 may be formed of molded or cast material. The outer edge or periphery of the diaphragm 32 is clamped between the

housing members

42 and 36 which may be secured together by suitable means, such as the bolts or screws 28, along with a sealing gasket (not shown) to thereby form an air-tight or fluid tight seal between the portion of the chamber above the diaphragm 32 and the portion of the chamber 40 below the diaphragm 32.

The time delay device It? may be secured to or supi ported on the supporting frame or member 34. shown in FIG. 3 by any suitable means, such as the bolts 82 and an opening is provided in the supporting member 34 through which the stem or shaft 38 passes, said opening or hole having a relatively larger diameter than the stem The upper housing member application of atmospheric pressure to the top of the dia-- phragm 32 through the opening 35 in the supporting member 34. The central portion of the diaphragm 32 is clamped between the upper and lower clamp members 76 with both of said clamp members andthe central portion of the diaphragm 32 being secured to the lower end of the stem 38 by suitable means, such as the rivet 63 to form an air-tight or fluid-tight seal at the point where the stem 38 is connected to the diaphragm 32. Since the spaces or portions of the chamber 40 above and below the diaphragm 32 are completely sealed off from each other and since the space above the diaphragm 32 is at atmospheric pressure, any force exerted on the stem 38 by the associated equipment indicated at 43 tending to raise the stem 38 and the diaphragm 32 upwardly from the position shown in FIG. 3 will be restrained or opposed by the partial vacuum which results below the diaphragm 32.

In order to control the rate of movement of the associated equipment indicated at 53 in FIG. 3 when the latter equipment attempts to move in an upward direction to the position indicated in phantom in 53 in FIG. 3 in response to an actuation of the associated equipment, the valve means or device 20 is provided to admit air or other fluid to the space below the diaphragm 32 at different rates to provide dilferent lengths or durations of time delayin the operation of the associated equipment indicated at 53. The valve device 20 includes a relatively small opening or passage 54 which extends through the central portion of the lower housing member 36 and a flat strip member or reed member which is formed from a relatively thin metal or other strip material having a certain degree of resiliency or stiffness and at least a moderately high yield strength, such as carbon spring steel or Phosphor bronze. As shown in FIG. 3, the strip member 52. is disposed to pass over the opening or passage 54 in the lower housing member 36 with the portion of the strip member 52 to the left of the opening being slidably supported to bear against the relatively flat bottom portion of the lower housing member 36 by the guide means 43 which may be secured to or'formed to or formed integrally with the lower housing member 36. As illustrated, the left portion of the strip member 52 also includes an upwardly extending portion 51 which is threadedly engaged by an adjusting or calibrating screw 64 which in turn is rotatably supported by a depending portion 42A of the upper housing member 42. The portion of the strip member 52 to the right of the opening or passage 54 is disposed to bear against a generally wedge-shaped member 53 which includes a cam or sloping surface 72 and which is secured to or formed integrally with the lower housing member 36. It is to be noted that the wedge-shaped member 59 biases or bends the portion of the strip member 52 to the right of the opening or passage 54 away from the portion of the lower housing member 36 which lies in substantially the same plane as the flat portion of the housing member 36 which lies to the left of the opening or passage 54. I

In the operation of the time delay device 10, when the strip member 52 is in a position indicated in phantom at 52 in FIG. 3, the strip member 52 substantially closes off the opening or passage 54 and substantially prevents the entrance or flow of air or other fluid into the space below the diaphragm 32 inside the chamber 40. When the strip member 52 which is relatively movable with respect to the wedge-shaped member 59 is moved to the right as indicated at 52 in FIG. 3, the portion of the strip member 52 to the right of the passage 54 is flexed or bent farther away from the main portion of the lower housing member 36 and a relatively thin, wedge-shaped passageway is defined between the strip member 52 and the bottom of the lower housing member 36 which leads into the passage or opening 54 and permits air or other fluid to enter the space below the diaphragm 32 at a predetermined rate when the associated equipment indicated at 53 is actuated to raise the stem or shaft 38 along with the diaphragm 32. The size or volume of the wedge-shaped passageway which is defined between the lower housing member 36 and the strip member 32 maybe varied to obtain different rates of air or fluid flow into the space beneath the diaphragm 32 by adjusting the calibrating screw 64 to thereby vary the position of the strip member 52 with respect to the cam surface 55 of the wedgeshaped member 59. It is to be noted that the size of the opening or passageway defined between the strip member 52 and the lower housing member 36 is determined both by the position of the portion of the strip member 52 to the right of the opening or passage 54 as just described i and also by the thickness and modulus of elasticity of the material from which the strip member 52 is formed. In a particular application, the thickness of the strip member 52 depends upon the desired variation in the size of the passageway defined between the housing member 36 and the strip member 52 which in turn depends upon the amount of deflection required in the strip member 52 and the modulus of elasticity of the material from which the strip member 52 is formed.

In summary, in the overall operation of the time delay device when the associated equipment indicated at 53 is actuated to move from the lower position shown in FIG. 3 to the upper position indicated at 53' in FIG. 3 to thereby attempt to raise the shaft or stem 38, the corresponding raising of the diaphragm 32 creates a partial vacuum below the diaphragm 32 which results in a force being exerted on the stem 38 which opposes the force exerted on the stem 38 through the associated equipment indicated at 53 to thereby retard the upward movement of the member 53 for a predetermined time delay. The duration of the time delay depends upon the rate of flow of air or other fluid into the space below the diaphragm 32 through the opening or passage 54 and the generally wedge-shaped passageway which is defined between the housing member 36 and the strip member 52 to thereby overcome the partial vacuum which initially results. As previously explained, the predetermined time delay which is provided by the time delay device It) depends upon the setting of the calibrating screw 64 and the corresponding size of the generally wedge-shaped passageway which is defined between the housing member 36 and the strip member 52.

Referring to FIGS. 4 and 5, the time delay device 210 illustrates a second embodiment of the invention. In general, the time delay device 210 is similar to the time delay device 10 previously described except that the left portion of the strip member 252 is held in a relatively stationary or fixed position and the generally wedgeshaped member 259 is formed as a separate part which is adjustably movable with respect to the stationary strip member 252. In this instance, the left portion of the strip member 252 is fixedly secured to the substantially flat portion of the lower housing member 236 by the supporting means 248 and suitable fastening means, such as the screws 292. The wedge-shaped member 259 includes a cam or sloping surface 272 against which the portion of the strip member 252 to the right of the opening or passage 254 bears with the wedge-shaped member 259 being slidably supported to move along the substantially flat surface of the lower housing member 236 by the calibrating screw 264 which, in turn, is supported by the depending portion 237 of the lower housing member 236.

The balance of the parts of the time delay device 210 include .a flexible diaphragm 232 and a stem or shaft 238 along with other parts which are identical to those previously described in detail in connection with the time delay device 10. The operation of the time delay device 210 is the same as previously described in connection with the time delay device 10 except that the duration of the time delay is varied by adjusting the calibrating screw 264 to move the wedge-shaped member 259 relative to the strip member 252.

Referring now to FIG. 6, the time delay device 310 illustrates a third embodiment of the invention. The time delay device 310 is similar to the time delay device 10 previously described in detail, except that the portion of the strip member 352 to the left of the opening or passage 354 is fixedly secured to the lower housing member 336 by the supporting means 348 and suitable fastening means, such as the screws 392. In addition, the portion of the strip member 352 to the right of the opening 354 is deflected or bent away from the lower housing member 336 by the calibrating or adjusting screw or post 364 which extends downwardly from the lower housing member 336 to bear against the portion ofthe strip member 352 to the right of the opening or passage 354. The time delay device 310 also includes a flexible diaphragm 332 and a stem or shaft 338 along with other parts which are identical to those previously described in connection with the time delay device 10. The operation of the time delay device 310 is similar to the time delay device 10 except that the duration of the time delay provided is varied by adjusting the calibrating screw 364 to vary the size of the passage between the strip member 352 and the housing member 336 adjacent to the opening 354.

The apparatus embodying the teachings of this invention has several advantages. For example, as long as the strip member in each of the embodiments disclosed is not flexed or stressed beyond the yield strength of the material from which it is formed, the time delay setting of the device may be readily returned to any operating point by a precise adjustment of the calibrating or adjusting screw. In addition, in the time delay device as disclosed, any linear or other relationship may be provided between the length of the time delay provided and the adjustment of the calibrating or adjusting screw by suitably shaping the cam or sloping surface of the wedge-shaped member included in the first and second embodiments. A further advantage is that the change in the length of the time delay provided by the time delay device disclosed is a very gradual change so that the time delay may be adjusted to a relatively precise value over a wide range by changing the adjusting or calibrating screw position. It is important to note that in the time delay devices disclosed, the change in the length of the time delay which results from an adjustment of the calibrating screw does not result directly from the change in position of the calibrating screw as in a valve of the needle-type but rather indirectly through the change in the relative positions of the strip member and the associated wedge-shaped member in the first and second embodiments of the invention. A final'advantage of the time delay device as disclosed is the ease of manufacture since it is not necessary to maintain relatively precise shapes and dimensions of the different parts of the time delay device as in a valve of the needleyp Since numerous changes may be made in the abovedescribed apparatus, and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

l. A time delay device comprising an enclosing housing having a cavity therein, a flexible diaphragh dis-' posed to seal ofl one portion of the space in said cavity from the space in the other portion of said cavity, a passageway extending through saidhousing into said one portion of the space in said cavity which is otherwise sealed off by said diaphragm, and a resilient flat strip member disposed to pass over one end of said passageway, a portion of said strip member on one side of said passageway disposed to bear against said housing, and means for biasing the portion of said strip member on the other side of said passageway away from said housing to define a generally wedge-shaped, relatively thin passage between said housing and said strip member leading into said passageway.

2. A time delay device comprising an enclosing housing having a cavity therein, a flexible diaphragm disposed to seal off one portion of the space in said cavity from the space in the other portion of said cavity, a passageway extending through said'housing into said one housing with one end of said member bearing against the biased portion of said strip member.

4. A time delay device comprising an enclosing housing having a cavity therein, a flexible diaphragm disposed to seal off one portion of the space in said cavity from the space in the other portion of said cavity, a passageway extending through said housing into said one portion of the space in said cavity which is otherwise sealed off by said diaphragm, and a resilient flat strip member disposed to pass over one end of said passageway, a portion of said strip member on one side of said passageway disposed to bear against said housing, means for biasing the portion of said strip member on the other side of said portion of the space in saidcavity which is otherwise sealed ofl by said diaphragm, and a resilient fiat strip member disposed to pass over one end of said passageway, a portion of said strip member on one side of said passageway disposed to bear against said housing, and means for biasing the portion of said strip member on the other side of said passageway away from said housing to define a generally wedge-shaped, relatively thin passage between said housing and said strip member leading into said passageway, the latter means comprising a cam shaped member against which the biased portion of said strip member bears.

3. A time delay device comprising an enclosing housing having a cavity therein, a flexible diaphragm disposed to seal off one portion of the space in said cavity from the space in the other portion of said cavity, a passageway extending through said housing into said one portion of the space in said cavity which is otherwise sealed otf by said diaphragm, and a resilient flat strip member disposed to pass over one end of said passageway, a portion of said strip member on one side of said passageway disposed to bear against said housing, and means for biasing the portion of said strip member on the other side of said passageway away from said housing to define a generally wedge-shaped, relatively thin passage between said housing and said strip member leading into said passageway, the latter means comprising an elongated cylindrical member extending outwardly from said passageway away from said housing to define a generally wedgeshaped, relatively thin passage between said housing and said strip member leading into said passageway, the latter means comprising an elongated cylindrical member extending outwardly from said housing with one end of said member bearing against the biased portion of said strip member, and means secured to said diaphragm to permit the application of a force to said diaphragm tending to increase said one portion of the space in said cavity sealed off by said diaphragm.

5. A time delay device comprising a housing having a chamber therein, a flexible diaphragm sealing oil. at least a portion of said chamber from the other side of said diaphragm, an opening in said housing leading into the portion of said housing which is otherwise sealed off by said diaphragm, and a flat strip member disposed to pass over said opening and to bear against the housing at only one side of said opening, the fiat strip member being disposed to flex away from the housing on the other side of said opening to define a generally wedge-shaped, relatively thin passageway leading into said opening from the exterior of said housing, said flat strip member being restrained from movement away from said housing at said one side of said opening.

6. A time delay device comprising a housing having a chamber therein, a flexible diaphragm sealing off at least a portion of said chamber from the other side of said diaphragm, an opening in said housing leading into the portion of said housing which is otherwise sealed ofif by said diaphragm, a flat strip member disposed to pass over said opening and to bear against the housing at only one side of said opening, the flat strip member being disposed to flex away from the housing on the other side of said opening to define a generally wedge-shaped, relatively thin passageway leading into said opening from the exterior of said housing, said flat strip member being restrained from movement away from said housing at said one side of said opening and means secured to said diaphragm to permit the application of a force to said diaphragm tending to increase the portion of said chamber sealed off by said diaphragm.

7. A valve device comprising a housing having an inlet and an outlet, a passage extending between said inlet and said outlet, and a resilient flat strip member disposed to pass over said inlet and to bear against said housing at one side of said inlet, and means for biasing the portion of said strip member on the other side of said inlet away from said housing to define a generally wedge-shaped, relatively thin passageway between said housing and said strip member which communicates with said passage.

8. A valve structure comprising a body member having a passage extending therethrough, a resilient reed member disposed to pass over one end of said passage, a first portion of said reed member being disposed to bear against said body member on one side of said one end of said passage, and means for flexing a second portion of said reed member on the other side of said one end of said passage away from said body member to define a generally wedge-shaped, relatively thin passageway between said reed member and said body member leading into said passage.

9. A valve structure comprising a body member having a passage extending therethrough, a resilient reed member disposed to pass over one end of said passage, a first portion of said reed member being disposed to bear against said body member on one side of said one end of said passage, and means for flexing a second portion of said reed member on the other side of said one end of said passage away from said body member to define a generally wedge-shaped, relatively thin passageway between said reed member and said body member leading into said passage, the last-mentioned means comprising a cam-shaped member disposed on said other side of said one end of said passage with the second portion of said reed member bearing against said cam-shaped member.

10. A valve structure comprising a body member having a passage extending therethrough, a resilient reed member disposed to pass over one end of said passage, a first portion of said reed member being disposed to bear against said body member on one side of said one end of said passage, and means for flexing a second portion of said reed member on the other side of said one end of said passage away from said body member to define a generally wedge-shaped, relatively thin passageway between said reed member and said body member leading into said passage, the last-mentioned means comprising an elongated cylindrical member projecting outwardly from said body member to bear against the second portion of said reed member.

11. A valve device comprising a body member having a passage therethrough, said body member including a flat portion on one side at one end of said passage and a cam portion at the other side at said one end of said passage projecting away from said one end of said passage, and a resilient, flat strip member disposed to pass over said one end of said passage with one portion of said strip member bearing against the flat portion of said body member and a second portion of said strip member bearing against said cam portion to define a generally wedgeshaped, relatively thin passageway between said strip member and said body member leading into said passage.

12. A valve device comprising a body member having a passage therethrough, said body member including a fiat portion on one side at one end of said passage and a cam portion at the other side of said one end of said passage projecting away from said one end of said passage, and a resilient, flat strip member disposed to pass over said one end of said passage with one portion of said strip member bearing against the flat portion of said body member and a second portion of said strip member bearing against said cam portion to define a generally wedgeshaped, relatively thin passageway between said strip member and said body member leading into said passage, said strip member being slidably movable with respect to 0 said body member to vary the effective size of said passageway.

13. A valve device comprising a body member having a passage therethrough, said body member including a fiat portion on one side at one end of said passage and a cam portion at the other side at said one end of said passage projecting away from said one end of said passage, and a resilient, flat strip member disposed to pass over said one end of said passage with one portion of said strip member bearing against the fiat portion of said body member and a second portion of said strip member bearing against said cam portion to define a generally wedgeshaped, relatively thin passageway between said strip member and said body member leading into said passage, said cam portion of said body member being movable with respect to the balance of said body member to vary the effective size of said passageway.

References Cited by the Examiner UNITED STATES PATENTS 358,568 3/1887 Potter 137-22l 939,549 11/1909 Reineking 137525.3 2,855,481 10/1958 Lindahl 188-94 2,974,754 3/ 1961 Landbrecht 18895 3,053,275 9/1962 Waterfill 137521 FOREIGN PATENTS 120,175 7/ 1945 Australia. 987,301 8/1951 France.

MILTON BULCHER, Primary Examiner.-

ARTHUR L. LA POINT, Examiner.

H. R. FIELD, G. HALVOSA, Assistant Examiners.

Claims

7. A VALVE DEVICE COMPRISING A HOUSING HAVING AN INLET AND AN OUTLET, A PASSAGE EXTENDING BETWEEN SAID INLET AND SAID OUTLET, AND A RESILIENT FLAP STRIP MEMBER DISPOSED TO PASS OVER SAID INLET, AND TO BEAR AGAINST SAID HOUSING AT ONE SIDE OF SAID INLET, AND MEANS FOR BIASING THE PORTION OF SAID STRIP MEMBER ON THE OTHER SIDE OF SAID INLET AWAY FROM SAID HOUSING TO DEFINE A GENERALLY WEDGE-SHAPED, RELATIVELY THIN PASSAGEWAY BETWEEN SAID HOUSING AND SAID STRIP MEMBER WHICH COMMUNICATES WITH SAID PASSAGE.