US3681721A

US3681721A - Time delay switch

Info

Publication number: US3681721A
Application number: US160426A
Authority: US
Inventors: Paul D Wessel; Max A Nelson
Original assignee: Essex International Inc
Current assignee: Raytheon Technologies Corp
Priority date: 1971-07-07
Filing date: 1971-07-07
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01
Also published as: CA940987A

Abstract

A time delay switch including a sealed housing divided into a pair of chambers by a flexible diaphragm. A reset orifice pin communicates the chambers with each other and includes a pair of openings in one of the chambers one of which has a flow restriction orifice therein and the other of which is operatively associated with a poppet assembly to be opened and closed by the latter. Switching means is responsive to the position of the diaphragm such that when the diaphragm has been urged upward to a first position by the poppet assembly the poppet is withdrawn from the reset orifice pin in response to movement of the switching means to allow the diaphragm to move to a second position. In the second position, the poppet assembly, in response to movement of the switching means, again acts against the reset orifice pin to move the diaphragm toward the first position at a delayed rate determined by the flow restriction orifice.

Description

United States Patent Wessel et al.

[451 Aug. 1, 1972 [54] TIME DELAY SWITCH Primary Examiner-Harold Broome [72] Inventors: Paul D. Wessel, Loganspon; Max Attorney-Mohnare, Allegretti, Newitt & witcofi Nelson Aubur, both of lnd. 57 ABSTRACT [73] Asslgnee: Essex International, Inc., Ft. Wayne,

A time delay switch including a sealed housmg divided into a pair of chambers by a flexible diaphragm. A Flled? Y 7, 1971 reset orifice pin communicates the chambers with [211 160,426 each other and includesa pair of openings inone of the chambers one of which has a flow restriction onfice therein and the other of which is operatively as- [52] U.S.Cl. .335/61, 200/34, 200/83 T, sociated with a poppet assembly to be opened and [5]] l Cl 54 33? closed by the latter. Switching means is responsive to [.1 the position of the diaphragm Such that when the [58] held of Search 33 ,i, 3? 2 diaphragm has been urged upward to a first position 335/2 2 0/ 3 3 l by the poppet assembly the poppet is withdrawn from 6 R f C1 d the reset orifice pin in response to movement of the [5 1 e erences I e switching means to allow the diaphragm to move to a UNITED STATES PATENTS second position. In the second position, the poppet assembly, in response to movement of the switching 2,855,481 /1958 Lmdahl ..335/6l means again acts against the reset orifice pin to move 3,103,612 9/1963 Marmo ..335/240 the diaphragm toward the first position at a delayed 3,2] 1,417 10/1965 Ray ..251/54 rate determined by the flow restriction Orifice 3,246,094 4/1966 Zaske et al ..200/34 18 Claims, 2 Drawing Figures 8/ 42 /0\ u W I 22 27 I 32 Q & mm

23 t 1 72 I4- 26 s? *1 M475 I 78 r 94' 62 I" v 97 9a so 2 W k 88 ,8 in 8 6 /2 TIME DELAY swrrcn This invention relates to a time delay switch and, more particularly, to a new and improved time delay switch for delaying the operation of contacts for a predetermined period of time.

Time delay switches find a wide variety of uses, such as in air conditioning compressor control circuits to prevent fast compressor recycling and in clothes dryer anti-wrinkle time delay circuits. In such circuits it is frequently desirable to open the circuit for a predetermined period of time which may be of considerable length. The time delay switch constructed in accordance with the principles of the present invention is relatively simple in construction and therefore may be of low cost and yet is both accurate and reliable in operation and is capable of effecting delayed contact operation of upward of five or more minutes. Moreover, the time delay switch constructed in accordance with the principles of the invention, may be employed to control one or several electrical switching contacts simultaneously and one of the contact sets may be instantaneously operated. In the switch of the present invention, a snap action switch may be employed and its operation may be selectively delayed and its reset controlled.

The time delay apparatus constructed in accordance with the principles of the invention includes housing means which defines a sealed enclosure and flexible partition means in the housing means divides the enclosure into first and second sealed chambers, the partition means being movable between first and second positions in the housing to decrease the volume of the first and second chambers, respectively. A passage positioned in reset means on the partition means and flow restriction means communicate the first and second chambers with each other. Poppet means are movable so as to close the passage in the second chamber and urge the partition means toward its first position, the flow restriction means restricting the flow of fluid from the'first to the second chamber to limit the rate of movement of the partition means toward the first position. The poppet means are also movable to open the passage to the flow of fluid from the second to the first chamber such that the partition means will move toward the second position in response to the movement of the poppet means in the latter direction. Circuit means are operatively associated with the time delay apparatus and switching means are responsive to the movement of the partition means between its positions to place the circuit means in a first condition and move the poppet means into closing relationship with the passage when the partition means reaches the second position and to place the circuit means in a second condition and move the poppet means into opening relationship to the passage when the partition means reaches the first position.

These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING In the course of this description, reference will frequently be made to the attached drawing in which:

FIG. 1 is a cross sectioned elevation view of a time delay switch constructed in accordance with the principles of the present invention and showing the diaphragm of the switch in its uppermost position and beginning to move downward, and

FIG. 2 is a cross sectioned elevation view of the switch shown in FIG. 1, but in which the diaphragm is in its lowest position and beginning to move upward.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, a preferred embodiment of time delay switch is shown which is constructed in accordance with the principles of the invention. The preferred switch of the present invention comprises a sealed housing 10 formed by a complementary cupshaped upper cover 11 and lower body 12 each of which is flanged at 13 and l4-respectively about its perimeter. The flanges l3 and 14 of the cover 11 and body 12 are firmly attached together by way of bolts 15 or other suitable fastening means. A suitable resilient sealing gasket 16 is preferably positioned between the flanges l3 and 14 to seal the enclosed compartment 18 formed between the cup-shaped cover and body and the compartment is filled with a suitable fluid, preferably air.

A flexible partition assembly 20 is also positioned in the housing so as to divide the sealed enclosed compartment 18 into an upper first chamber 22 and second lower chamber 24. The partition includes a resilient diaphragm 26 which is attached about its periphery between flanges l3 and 14 and a pair of

rigid discs

27 and 28 are concentrically arranged on each side of the diaphragm 26 to add a measure of rigidity to the diaphragm. These

discs

27 and 28 are smaller in diameter than the diaphragm 26, thus enabling the diaphragm to continue to be able to flex as shown in FIGS. 1 and 2 in the area between the discs and the perimeter of the diaphragm.

Discs

27 and 28 are preferably slightly cupshaped having an upturned perimeter 30 to enhance the strength of discs and avoid sharp edges in contact with the diaphragm which might damage the diaphragm during operation.

An elongated reset orifice pin 32 extends preferably through the center of the

dies

27 and 28 and diaphragm 26 and a passage 34 extends axially through the reset orifice pin to communicate the

sealed chambers

22 and 24 with each other. One end of the reset orifice pin 32 is flanged at 36 so as to provide a shoulder 38 which is adapted to be positioned adjacent the underside of disc 28 and a lock nut 40 is positioned adjacent the upperside of the reset orifice pin to lock the pin 32, the v diaphragm 26 and the

discs

27 and 28 into integral relationship with each other.

One end of passage 34 in the pin opens to chamber 22 by way of a flow restriction orifice 42, the purpose of which will be described later in the description of the operation of the present invention. The other end of the passage 34 opens at 44 to the other chamber 24 thereby providing communication between the chambers. A valve seat 46 is formed about opening 44 for cooperation with the poppet assembly 48 which will also be later described. In addition, a branch passage 50 is bored laterally through the flange 36 and communicates between chamber 24 and the passage 34. A reset flow restriction device, 'such as insert 52 having an orifice 54 therein, is positioned in the passage 50, this orifice 54 being selected to be of a size so as to determine the time delay of the present invention as will also be described later.

The poppet assembly 48 comprises a movable poppet valve 56 having a flat upper face 58 which faces valve seat 46. Valve 56 is nested in a cup-shaped washer 60 having a laterally extending flange 62 about its upper perimeter. A spring 64 is positioned about the cup-shaped washer 60 and acts against the underside of the flange 62 to urge the washer and poppet valve 56 mediate the length of the resilient arm 94 so as to be movable into contact with a stationary contact 98 within the housing which is electrically connected to a which is nested therein in an upward direction such that the face 58 of the valve will move into seating engagement with the valve seat 46 as shown in the dot and dash position in FIG. I and in solid in FIG. 2. In this spring urged position, the poppet valve 56 closes the opening 44 of passage 34 to chamber 24.

An actuating rod 66 is connected to the poppet valve 56 and extends through an opening 68 in the cupshaped washer 60. This actuating rod is operatively connected to a suitable power operating mechanism, such as a solenoid 70, so that when the solenoid is energized or actuated, the poppet valve 56 and its washer 60 are drawn in the downward direction as viewed in FIGS. 1 and 2 to the solid position shown in FIG. I againSt the upward force exerted by spring 64. In the downward position, the poppet valve face 58 is unseated from valve seat 46 to open the opening 44 of passage 34 in chamber 24.

The time delay switch of the present invention also includes a snap switching assembly 72 comprising first and

second terminals

73 and 74 having spaced stationary

electrical contacts

75 and 76, thereon. A third circuit completing terminal 77 also extends through the body 12 of the housing, as do the first and second terminals, and a movable actuator arm 78 is pivotally mounted at 80 on terminal 77. One end 81 of the actuator arm 78 extends toward the reset orifice pin 32 and is firmly clamped between the disc 28 and flange 36 of the pin as shown in FIGS. 1 and 2. The other end 82 of the actuator arm 78 extends downward from its pivotal mounting 80 on terminal 77. A movable contact arm 84 having contacts 86 thereon which are adapted to alternatively engage

contacts

75 and 76, is also pivotally mounted at 88 upon terminal 77. A spring 90 extends from a point intermediate the length of the contact arm 84 to the end 82 of the actuator arm 80. Contact 75 is preferably positioned in the electrical circuit (not shown) which is to be energized and deenergized by the time delay switch of the present invention and contact 76 is connected to one of the leads 92 of the solenoid actuating circuit, terminal 77 completing one or both of these circuits through the

contacts

75 or 76.

An additional auxiliary instantaneously actuated electrical circuit may also be employed if desired in the delay apparatus of the present invention. As shown in FIGS. 1 and 2, this auxiliary circuit may take the form of a resilient movable conductive contact arm 94 which is positioned'so as to be moved by the underside ofsecond auxiliary terminal 99 external of the housing.

Extreme movement of the diaphragm 26 beyond its uppermost and lowermost positions, which might cause early deterioration of the diaphragm, is prevented by contact of the upper end of the reset orifice pin with the inside of the cover 11 and stops 100 may be formed integrally with the body 12 to prevent excessive downward movement.

The operation of the preferred embodiment of time delay switch will now be described.

Referring to FIG. 1, let it be assumed that the flexible diaphragm 26 has been moved to its uppermost position as shown in FIG. 1. When the diaphragm has reached its uppermost position, the actuator arm 78 will have rotated in the clockwise direction as viewed in FIG. 1 and the end 82 of the arm will be in its lowermost position causing the axis of the spring 90 to move slightly below the movable contact arm 84. The spring force exerted by spring 90 will now have a downward component which will draw the movable contact arm 84 from the dot and dash position shown in FIG. 1 downward to the solid position opening the circuit in which contact 75 is located and contacting the contact 76 to close the solenoid actuating circuit. When the solenoid is energized, the poppet valve 56 and washer 60 will be drawn downward and the valve face 58 will be withdrawn from the valve seat 46, movement being from the dot and dash position to the solid position shown in FIG. 1.

Due to the weight of the diaphragm 26, the

discs

27 and 28 and reset orifice pin 32, the diaphragm will now move downward by gravity in the direction shown by the heavy arrows in FIG. 1. The rate of movement in this direction will be a function of both of the weight of the diaphragm, discs and reset pin and the compression of the air and vacuum which now occurs in

chambers

24 and 22, respectively. This compressed air from chamber 24 will flow upward into the passage 34 through opening 44 and through the flow restriction orifice 54 and will be transferred to the upper chamber 22 through orifice 42. It will be understood that this flow rate may be selectively varied by the selection of the size of orifice 42 such that the flow rate is somewhat restricted so as to restrain the rate of movement of the diaphragm 26 from the upper position toward the lower position.

As the diaphragm 26 moves downward, the actuator arm 78 will be rotated in a counterclockwise direction. When the diaphragm moves to its lowest position as shown in FIG. 2, the actuator arm 78 will have rotated so as to raise the end 82 thereof and cause the spring 90 to now exert a force on the contact arm 84 which has an upward component due to the change in the axial direction of the force exerted by the spring relative to movable arm 84. When the upward component of the force exerted by spring 90 is sufiicient, the contact arm 84 will flip with a snap action from the lower dot and dash position to the, upper solid position as shown in FIG. 2 into contact with contact to complete the circuit through the power circuit and will open the circuit to the solenoid 70.

When the circuit to the solenoid 70 has been opened, the poppet valve 56 will no longer be drawn downward as viewed in FIG. 1 and the spring force exerted by spring 64 will now urge the poppet valve upward against valve seat 46 to close opening 44 and to commence urging the diaphragm 26 again toward its upper position as shown by the heavy arrows of FIG. 2.

It will be seen that the rate at which the diaphragm 26 will now move from its lower position toward its upper position will be substantially restricted to achieve the time delay of the invention, since the gas which is compressed in chamber 22 can only flow from that chamber to chamber 24 at a restricted rate, since it must now pass through the flow restriction time delay orifice 54 as shown by the arrows in FIG. 2. Thus, the circuit which is being controlled by contact 75 will be energized for the predetermined amount of time which it takes the diaphragm 26 to move from the lower position shown in FIG. 2 upward to the upper position shown in FIG. l.'Once the diaphragm again reaches the upper position, the actuator arm 78 will again have been rotated such that the spring 90 exerts a downward force component upon the movable contact arm 84 to open the power circuit with a snap action and reenergize the solenoid 70 repeating the cycle previously described.

It will be seen that if

auxiliary contacts

97, 98 are provided, they will operate instantaneously in response to the actuation and deactuation of the poppet assembly 48. Thus, when solenoid 70 is energized and the washer 60 is drawn to its lower position as shown in solid in FIG. 1, the contact arm 94 will be urged downward to close

contacts

97 and 98. Conversely, when the solenoid 70 is deenergized and the spring 64 urges the washer 60 upward as shown in FlG. 2, the contact arm 94 will also move uPward and

open contacts

97 and 98.

It will be understood that, although the invention has been described in terms of a pneumatic time delay switch, other fluids, gaseous as well as liquid, may be employed in the switch of the present invention. Also it will be understood that the power actuating mechanism of the poppet assembly 48 may also be modified such that suitable mechanical, pneumatic or hydraulic means may be employed in place of the solenoid 70 in the above described invention.

Finally, it will be appreciated that the embodiment of the present invention which has been described is merely illustrative of an application of the principles of the invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.

What is claimed is 1. Time delay apparatus compriSing: housing means defining a sealed enclosure and having a predetermined volume of fluid therein,

movable flexible partition means in said housing dividing said enclosure into first and second sealed chambers, said partition means being movable toward a first position in which the volume of said first chamber is decreased and a second position in which the volume of said second chamber is decreased,

reset means on said partition means, said reset means having a passage therein opening to said first and second sealed chambers for communicating said chambers with each other, time delay flow restriction means communicating said first and second sealed chambers with each other,

poppet means movable in a first direction in which said poppet means closes the opening of said passage in said second chamber, and urges said partition means toward said first position, said delay flow restriction means restricting the flow of said fluid said first to said second chamber to limit the rate of movement of said partition means toward said first position, said poppet means also being movable in a second direction in which said poppet means opens said passage to the flow of said fluid from said second chamber to said first chamber, said partition means moving toward said second position in response to movement of said poppet means in said second direction,

circuit means operatively associated with said time delay apparatus, and

switching means responsive to the movement of said partition means between said positions to place said circuit means in a first condition .and move said poppet means in said first direction when said partition means reaches said second position and to place said circuit means in a second condition and move said poppet means in said second direction when said partition means reaches said first position.

2. The time delay apparatus of claim 1 wherein said movable flexible partition means comprises a diaphragm.

3. The time delay apparatus of claim 1 wherein said fluid is a gas.

4. The time delay apparatus of claim 1 wherein said reset means comprises an elongate pin, said passage extending axially therethrough, valve seat means adjacent the opening of said passage into said second chamber and positioned to be engaged by said poppet means when said poppet means is moved in said first direction to close said opening.

5. The time delay apparatus of claim 4 wherein said time delay flow restriction means communicates said second chamber with said passage independently of said valve seat means.

6. The time delay apparatus of claim 4 wherein said time delay flow restriction means comprises an orifice which opens into said passage between said flexible partition means and said valve seat means.

7. The time delay apparatus of claim 4 including an orifice in the opening of said passage into said first chamber.

8. The time delay apparatus of claim 1 wherein said poppet means includes spring means for urging said poppet means in said first direction and power means for urging said poppet means in said second direction against the force of said spring means when said flexible partition means is moving from said first position toward said second position.

9. The time delay apparatus of claim 8 wherein said power means is a solenoid.

10. The time delay apparatus of claim 8 wherein said power means is actuated to urge said poppet means in said second direction by said switching means.

11. The time delay apparatus of claim 1 wherein said partition means is urged toward said second position by gravity.

12. The time delay apparatus of claim 1 wherein said time delay flow restriction means communicates con-- tinuously between said first and second sealed chambers.

13. The time delay apparatus of claim 12 wherein said time delay flow restriction means continuously communicates said chambers. with each other through said passage.

14. The time delay apparatus of claim I wherein said switching means comprise:

first stationary electrical contact means in said circuit means,

second stationary electrical contact means operatively associated with said poppet means, and

third movable electrical contact means operatively associated with said partition means such that said first and third contact means are opened to deenergize said circuit means and said second and third contact means are closed to move said poppet means in said second direction when said partition means is moving from said first position toward said second position and said first and third contact means are closed to energize said circuit means and said second and third contact means are opened to move said poppet means in said first direction when said partition means is moving from said second position toward said first position.

15. The time delay apparatus of claim 14 wherein said switching means includes actuator means movable in response to the movement of said partition means, a contact carrying member upon which said third movable contact means are mounted, said contact carrying member being mounted for pivotal movement between said first and second contact means, and spring means connecting said actuator means and said contact carrying member, whereby said third contact means is moved by snap action between said first and second contact means in response to the position of said partition means.

16. The time delay apparatus of claim 1 including second switching means instantaneously operable in response to the movement of said poppet means.

17. Time delay apparatus comprising:

housing means defining an enclosure,

movable flexible partition means in said housing dividing said enclosure into first and second chambers at least one of which is sealed, said partition means being movable toward a first position in which the volume of said first chamber is decreased and a second position in which the volume of said second chamber is decreased,

reset means on said partition means, said reset means having a passage therein communicating said chambers with each other,

time delay flow restriction means communicating said first and second chambers with each other,

poppet means movable in a first direction in which said poppet means closes said passage adjacent said second chamber and urges said partition means toward said first position, said time delay o w estriction means restrictin t e ow of aid urd fiom said first to said second 6231336! to limit the rate of movement of said partition means toward said first position, said poppet means also being movable in a second direction in which said poppet means opens said passage to the flow of said fluid from said second chamber to said first chamber, said partition means moving toward said second position in response to movement of said poppet means in said second direction,

circuit means operatively associated with said time delay apparatus, and

switching means response to the movement of said partition means between said positions to place said circuit means in a first condition and move said poppet means in said first direction when said partition means reaches said second position and to place said circuit means in a second condition and move said poppet means in said second direction when said partition means reaches said first position.

18. The time delay apparatus of claim 17 wherein said time delay flow restriction means continuously communicates said second chamber with said passage and said first chamber independently of said poppet means.

Claims

1. Time delay apparatus compriSing: housing means defining a sealed enclosure and having a predetermined volume of fluid therein, movable flexible partition means in said housing dividing said enclosure into first and second sealed chambers, said partition means being movable toward a first position in which the volume of said first chamber is decreased and a second position in which the volume of said second chamber is decreased, reset means on said partition means, said reset means having a passage therein opening to said first and second sealed chambers for communicating said chambers with each other, time delay flow restriction means communicating said first and second sealed chambers with each other, poppet means movable in a first direction in which said poppet means closes the opening of said passage in said second chamber, and urges said partition means toward said first position, said delay flow restriction means restricting the flow of said fluid said first to said second chamber to limit the rate of movement of said partition means toward said first position, said poppet means also being movable in a second direction in which said poppet means opens said passage to the flow of said fluid from said second chamber to said first chamber, said partition means moving toward said second position in response to movement of said poppet means in said second direction, circuit means operatively associated with said time delay apparatus, and switching means responsive to the movement of said partition means between said positions to place said circuit means in a first condition and move said poppet means in said first direction when said partition means reaches said second position and to place said circuit means in a second condition and move said poppet means in said second direction when said partition means reaches said first position.

3. The time delay apparatus of claim 1 wherein said fluid is a gas.

9. The time delay apparatus of claim 8 wherein said power means is a solenoid.

12. The time delay apparatus of claim 1 wherein said time delay flow restriction means communicates continuously between said first and second sealed chambers.

13. The time delay apparatus of claim 12 wherein said time delay flow restriction means continuously communicates said chambers with each other through said passage.

14. The time delay apparatus of claim 1 wherein said switching means comprise: first stationary electrical contact means in said circuit means, second stationary electrical contact means operatively associated with said poppet means, and third movable electrical contact means operatively associated with said partition means such that said first and third contact means are opened to deenergize said circuit means and said second and third contact means are closed to move said poppet means in said second direction when said partition means is moving from said first position toward said second position and said first and third contact means are closed to energize said circuit means and said second and third contact means are opened to move said poppet means in said first direction when said partition means is moving from said second position toward said first position.

17. Time delay apparatus comprising: housing means defining an enclosure, movable flexible partition means in said housing dividing said enclosure into first and second chambers at least one of which is sealed, said partition means being movable toward a first position in which the volume of said first chamber is decreased and a second position in which the volume of said second chamber is decreased, reset means on said partition means, said reset means having a passage therein communicating said chambers with each other, time delay flow restriction means communicating said first and second chambers with each other, poppet means movable in a first direction in which said poppet means closes said passage adjacent said second chamber and urges said partition means toward said first position, said time delay flow restriction means restricting the flow of said fluid from said first to said second chamber to limit the rate of movement of said partition means toward said first position, said poppet means also being movable in a second dirEction in which said poppet means opens said passage to the flow of said fluid from said second chamber to said first chamber, said partition means moving toward said second position in response to movement of said poppet means in said second direction, circuit means operatively associated with said time delay apparatus, and switching means response to the movement of said partition means between said positions to place said circuit means in a first condition and move said poppet means in said first direction when said partition means reaches said second position and to place said circuit means in a second condition and move said poppet means in said second direction when said partition means reaches said first position.