US3521211A - Switch and delay mechanism - Google Patents

Description

July 21 .-1970 y, R. H. THORNER 3,521,211

SWITCH AND DELAY MECHANISM Filed Aug. 22, 196e l 2 Sheets-Shea 1 July 21, 1970 R, H, THORNE'R `3,'."." .?.l,21.l

SWITCH AND DELAY MECHANISM 'MII l l l Patented July 2l, 1970 3,521,211 SWITCH AND DELAY MECHANISM Robert H. Thorner, S750-F W. Chicago Blvd., Detroit, Mich. 48204 Continuation-impart of application Ser. No. 544,960,

Apr. 25, 1966, now Patent No. 3,399,541, dated Sept. 3, 1968. This application Aug. 22, 1968, Ser.

lint. Cl. H0111 37/02, 37/52, 37/62 U.S. Cl. 337-301 19 Claims ABSTRACT OF THE DISCLOSURE An electric switch delay mechanism is provided and a novel switch mechanism is adapted to be operated by the delay mechanism. A delay mechanism includes a latch or clutch member adapted to engage an-d hold the switch blade of a snap-action switch between its total travel to delay the initial or final action of the switch until released as a function of time or temperature, for example. The novel switch includes a -unique switch blade to cooperate with the delay mechanism to provide the same action in a single switch as normally provided in two switches.

This application is a continuation-in-part of my application, Ser. No. 544,960 tiled Apr. 25, 1966 for Control Device for Refrigeration System, now Pat. No. 3,399,541.

The present invention relates to a switch mechanism and a mechanism for delaying the action of one of the movable elements of a snap-action switch as a function of time, temperature, or any other control function.

At the present time, mechanisms which can rdelay the action of a switch for an extended time (such as 4 minutes or more) are very expensive. Also, the present low cost switch delay mechanisms are usually limited to short time-intervals and are limited in their application since they can only delay the on or oi positions of a switch. Frequently it is desired to operate switch means in three positions in which two of the positions conduct current with the third position not conducting current. In this instnace, when snap-action switches are used, two switches are usually required.

One of the objects of the present invention is to provide an improved delay mechanism of very simple construction to enable low cost manufacture, and in which :relatively long time-delays are possible.

Another object of the present invention is to provide an improved delay mechanism of the character specified in the preceding paragraph, and which includes a si-mple thermal timer mechanism enabling improved reliability and low-cost manufacture.

A further object of the present invention is to provide an improved switch mechanism, per se, or in combination with the delay mechanism specified in the preceding paragraphs which, in a single switch provides the action of a plurality of switches.

Further objects and advantages of the present invention will be apparent from the following description, taken in connection with the -appended drawings, in which:

FIG. 1 is an elevational View of the control device Afor illustrating an application of the present invention;

FIG. 2 is a fragmentary elevational view of a modified 'form of the illustrated control device showing a temperature-sensitive form of the present invention;

FIG. 3 is a fragmentary elevational view of a modified form of the illustrated control device showing a timesensitive form of the present invention;

FIG. 4 is a fragmentary elevational View of a modified form of the invention for use in any kind of control device responsive to any kind of controlled condition;

FIG. 5 is an elevational view of the main elements to modify the form of the invention shown in FIG. 4 to provide a reverse action;

-It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to FIGS. 1, 2 and 3, which are the same as FIGS. 6, 12 and 13, respectviely, of vthe parent application, Ser. No. 544,960, the -present invention will first be illustrated as part of a defrost control for refrigeration machines. The defrost control device, per se, is not the subject of the present invention, since it was completely described and claimed in the parent application.

Referring to FIG. l, the entire defroster control is shown encased in a housing 11, and includes a pair of legs or supports 412 and 13 adapted to be secured to the refrigerator at any suitable position on the frost-forming surface. The defroster control may be considered to comprise two components; one component comprises an -initiating mechanism or means 14; and the second component comprises a termination mechanism 15 which controls the duration (or termination) of the defrosting action as shown in FIG. 1.

Temporarily referring to FIG. l, to be discussed in detail hereinafter, the termination mechanism 15 comprises switching means including an electric switch having a fixed abutment or contact 39 connected to a terminal 40, and an opposed fixed abutment or Contact 42 connected to a terminal 44. A movable switching contact 46 is carried by a switch blade or arm 48 swingable about a knife-edge connection in a support 50 which is connected to a stationary terminal 52. A strong extension spring 53 is connected at one end to the contact arm 48 and at its other end to switch actuator means including an actuator arm 54 which has knife-edge connection with support 50. The switch is shown in its normal position without the defrosting system in operation, and in this position terminal 52 is electrically connected to terminal 40 through contact 46 resting on contact 39 by the force of spring 53. When arm 54 is moved to the left, as viewed in FIG. l, by means to be described, spring 53 is moved over-center to the right, as viewed in FIG. 1, so that contact 46 snaps against contact 42 to electrically disconnect terminal 52 from terminal 40 and connect to terminal 44. In this position, however, the spring 53 maintains a relatively large force urging the arm 54 back to the original position shown in the drawings since the position of the spring is always at the left of the fulcrum of the arm 54. When arm 54 is moved back to its original position shown, the contact 46 is also snapped back to its original position as shown in FIG. l. Another terminal 55 is provided for reasons to be discussed hereinafter.

The action of the refrigerator and defroster control is as follows: When the refrigerator thermostat switch (not shown) is closed, with the defroster control switch in the position shown in FIG. l, the compressor lowers the freezer temperature in a normal manner until shut off by the thermostat. However, when the defroster control causes arm 54 to move to the left in a manner to be described, the refrigerator compressor is turned off and the defrost heater is energized until all the frost melts and is evaporated, all in a manner well known in the art. At this time the air circulation fan is turned off when contact 46 leaves contact 39. Afer all the frost is melted, the

defroster control causes arm 54 and contact 46 to return to the position shown in FIG. 1, by means to be described, which restores normal refrigeration and starts the circulation fan.

Now referring to FIG. l, the means to control the termination of the defrosting action will iirst be explained. In the component 15, the mechanism is encased in the housing 11 of any suitable material such as molded plastic. A wall of the housing is formed by the electrical insulating base 69 for the switch, which base is inserted in slots molded in the housing and retained by the housing cover which is shown removed in FIG. 1. In component 15, the arm 54 carries a detent member 72 hinged thereto by a knife-edge 73 at one end to permit angular movements of the detent in relation to arm 54. A light extension spring 74 is suitably secured at one end tothe housing 11 (or to a post secured thereto) and at its other end to a portion of detent 72 urging the detent downwardly into engagement with a cam or guide member 77.

A shaft 80, which may be a molded portion of the plastic housing 11, is provided to support a latch member or arm l82 for angular movements with respect to the shaft. A very light torsion spring 84 is suitably supported by a cylindrical projection of molded housing 11 to abut latch member 82 and to urge same in a counterclockwise direction into the free position shown in FIG. 1 into abutment with stop means to be discussed. Detent 72 includes a catch portion 88 disposed to engage latch member 82 in a manner to be described.

A small vessel 96, as shown in FIG. 1, is suitably secured to a portion of the evaporator tube such that the vessel is at least partly below the tubing. The vessel, which is filled with a freezable liquid such as water, may be made of any suitable material. The vessel is mounted to enable a sensing member 98, which comprises a portion of latch member 82, to extend inside an ice chamber 100 formed by the vessel. Whenever the water in vessel 100 is frozen, the sensor portion 98 is embedded and locked in the ice to prevent clockwise rotation of the arm 82.

The operation of the termination mechanism above described is as follows. Referring to FIG. 1, assume that chamber 100 of vessel 96 is completely lled with water or other freezable liquid which is frozen in normal refrigerator operation. After frost forms on the evaporator 30 to an undesirable amount, the arm 54 is automatically moved temporarily to the left by means to be described. This action causes contact -46 to move against contact 42 which inactivates the compressor and circulation fan but energizes the defrost heater adjacent the evaporator for melting and disposing of the frost. At this time the ice or frozen liquid in vessel 96 is also subjected to heat somewhat by radiation but primarily by conduction from the defrost heater. Also, movement of the switch arm to its leftward position carries detent 72 leftward until spring 74 causes catch portion 88 to engage latch arm 82. The leftward actuating force on arm 54 is simultaneously removed, as will be described. Then the force of spring 53 tends to return arm 54 into the position shown with a force that easily overpowers the force of spring 84. Such forces are transmitted through detent 72 which now abuts latch arm `82 at catch portion 88 tending to impart clockwise angular movement to arm 82. However, such angular movements are prevented by the sensor 98 now abutting against the ice or frozen liquid in vessel 96 which tends to be compressed between the sensor 98 and the inside wall 96a of the vessel. Thus, the ice acts as an ice or frozen-liquid link which grows smaller gradually as the ice or frozen-liquid progressively melts since contact with the melting ice is maintained by spring 53. As arm 54 with its detent member 72 gradually moves rightwardly when the ice in vessel 96 melts, the end of the detent member rides on cam 77 which gradually raises the detent member in opposition to spring 74. After a predetermined travel of arm 54 and detent 72 which is calibrated to occur when all the frost is melted, the catch portion 88 disengages from latch arm 82. This instantly causes two simultaneous actions as follows: The first action is that spring 84 instantly returns latch member 82 counterclockwise into the angular position shown in FIG. 1; accordingly the sensor 98 is moved through the path of melted ice and away from the remaining ice and restored to its original position shown. The second simultaneous action is that the high force of spring 53 causes arm 54 and detent 72 to snap into the positions shown in FIG. l, which also moves the contact 46 into the position shown against contact 39. This terminating action de-energizes the defrost heater and starts the compressor and air circulation fan so that refrigerator operation is again normal. The cornpressor is again controlled only by the refrigerator thermostat, and the ice in the vessel 96 soon freezes so that the defrosting cycle can be repeated as above described.

Means are provided to produce the small input power force or energy required to operate the initiation mechanism. In the form of the defrost control illustrated in FIG. 1, such input-power means comprises a heat-sensitive element which alternately is heated and cooled under control of a switch operated by the element itself to alternate the application of the heat energy. Referring to FIG. l, the thermal element illustrated therein comprises a bimetal leaf or strip cantilever member suitably secured at one end to housing 11. The bimetal includes a U-shaped end portion 151. An electric-switch contact 152 is carried by the bimetal to alternately engage another contact 154 carried by a knife-edge arm or blade 156 disposed for arcuate movements within the U-por- -tion 151. The contact 152 is insulated from the bimetal by suitable non-conducting material wherein the bimetal is electrically inert. An electric heating element or heater 158 is shown connected between terminals 40 and 5S and is controlled by contacts 152 and 154. The heating element 158 is either wound around bimetal 150 or otherwise mounted adjacent thereto. A bowed U-shaped leaf member 160 has one end projecting through an aperture at an intersecting point 162 in blade 156 and the other end in a V-slot 161 molded in housing .11 to urge the knife end of blade 156 against another V-slot 163 in housing 11. The force of leaf member 160 causes blade 156 to snap either up or down as the intersecting point 162 passes above or below, respectively, a straight line between the two V-slots in housing 11. In this manner, contacts 152 and .154 are snapped apart or together as shown. When the bimetal 150 is heated after about one to two minutes, for example, it moves upwardly enough to snap contact 154 away from contact 152 against a plastic stop 164 secured to U-portion 151, thereby deenergizing the heater 158. The bimetal now cools and warps downwardly for about one or two minutes until contact 154 passes the mid-position of intersection point 162 to snap the contacts together and re-energize heater 158. In this manner, the heating and cooling cycle is continuous while the compresser is in operation as illustrated in FIG. 1, to be discussed further.

This particular flasher-type self-controlling switch has utility, per se, especially when provided as a part of a bimetal timer in the present invention. This unique construction enables design-selection of the time for the heating portion of the cycle and also the time for the cooling portion of the total time-cycle. This is accomplished by (l) varying the distance between contact 152 and the stop 164 and (2) the initial angular position of bimetal 150 in relation to the line between the two V- slots 161 and 163. An increase in the distance between contact 152 and stop 154 increases the time of the overall cycle, and conversely. If the bimetal is initially positioned so that contact 152 is closer to the line between slots 161 and 163 than stop 164, the heating time tends to be less than the cooling time, and conversely. This general principle is modified somewhat by other factors such as the rate of heating of the various elements compared to the rate of cooling thereof, but this unique construction enables some design control separately of the heating and cooling periods.

A ratchet arm, such as leaf element .166, is secured to bimetal 150 and is insulated by suitable means to be electrically inert. The ratchet-arm and bimetal together comprise the movable actuating means. The ratchet arm er1- gages the teeth 128 of wheel 126 so that each downward movement of bimetal 150 moves wheel 126 one toothlength in a counterclockwise direction; reverse movements are prevented by a pawl 170. With 60 teeth in wheel 126, for example, and a total bimetal time cycle of 3 minutes, the Wheel will rotate one turn in 180 minutes or three hours. Hence, in this example, the defroster control res once every three hours of compressor operation.

Means for storing energy in spring 142 comprises a cam 182 which is connected to or is a part of the ratchet wheel 126 for rotation therewith when bimetal 150 reciprocates upon heating and cooling thereof, all as described above. An actuator power element .184 includes a cam follower tab 186 which projects over the cam surface for moving actuator 184 rightwardly upon rotation of wheel 126 counterclockwise. When the energy is stored in spring 142, a step 188 of cam 182 passes by tab 186 to release actuator 184 which initiates the defrosting action.

The open vessel 96 is mounted adjacent coil 30 in the ow path of melted frost. The latch member 82 includes the sensing portion 98 projecting within the vessel to abut ice between it and the left wall 96a of the vessel during the defrosting periods. A semi-cylindrical starter member 194 is loosely connected to sensor 98 with universal movement for enabling the starter to slide on tube 30. When the refrigerator is first placed in service with no water in vessel 96, the starter 194 is restrained by resistance of frost on tube 30. The melted frost gradually fills vessel 96 in subsequent defrost cycles, and the vessel is maintained full in this manner thereafter. A more complete discussion of this form of ice sensor is presented in my Pat. No. 3,350,894.

FIGS. 2 and 3 disclose modifications of the prior form of the invention, which modifications include novel means for delaying the compressor (and/or fan) operation after termination of the defroster cycle. In the form shown in FIG. 2, the switch blade 211 differs from blade 48 because of extension 212 which extends to the side of terminal-piece 44. The contact 42 is spaced further from contact 39 than in the prior form of the invention to pro- Ivide increased travel, such as 50-75% more, for example. A bimetal restrainer or latch member 213 is suitably secured to housing 11, as by riveting, and includes a catch portion 215 disposed to restrain extension 212 in the following manner: the bimetal 213 is shown in the cold position during normal refrigeration when the ternperature surrounding the defroster control might be degrees'F., for example. When the latch 122 is caused to actuate arm 54, contact 46 snaps from contact 39 to contact 42 to start the defrost heater and stop the compressor and circulation fan. When all the frost has melted, the ambient temperature is about 65 degrees F. This high temperature causes the bimetal 213 to warp downwardly (FIG. 2) to the position 213:1, shown dotted. When the defrosting cycle is terminated, the detent 72 and arm 54 are released from latch member 82 so that blade 211 snaps to the left to the position 2.12a. However, the catch portion 215 of bimetal 213 holds and detains the blade extension 212 in a position to maintain contact 46 part-way between contacts 39 and 42. At this time, the defrost heater is off, and the compressor is not started. When the ambient temperature cools to about -30 F., for example, bimetal 213 Warps upwardly enough to release the end of extension 212, and contact 46 then snaps to contact 39 to start the compressor and fan. The catch 215 can be made of plastic and secured to the bimetal to make it inert electrically. A delay mechanism is desired by some refrigerator manufacturers to enable the referigerant to cool down before starting the compressor.

The modification shown in FIG. 3 provides a delay of the switch action in the same manner as in FIG. 2, except the delay is based on time instead of temperature. In FIG. 3, a switch blade 217 includes an extension 219 with a catch portion 219a arranged so that the extension is behind terminal portion 44. A restrainer or clutch member 221 includes a slot 223 cooperating with the boss of shaft 118 to provide a hinge for enabling slight angular and longitudinal movements of the restrainer 221. The restrainer includes a latch portion 225 adapted to cooperate with extension 219. A spring 227 has one end connected to the housing and provides a very light force (such as one-half ounce) to urge restrainer 221 in both a rightward movement and a slight clockwise movement. Spring 227 is always overpowered by spring 53 which provides a force acting on extension 219 of about 6 ounces, for example. The restrainer includes a clutch or lock-portion 229 including teeth 231 disposed to engage the teeth 128 of wheel 126. The heater element 158 must be connected to terminal 52 so that the wheel 126 rotates at all times in the modification of FIG. 3.

In operation, when arm 54 is moved to the left to initiate the defrost action, contact 46 snaps to contact 42 which is spaced further from contact 39 as in the form of FIG. 2, thereby energizing the defrost heater. At this time the blade extension catch 219a passes over the end of latch portion 225. When detent 72 is released from latch member 82 at the end of the defrost cycle, the switch blade 217 snaps to the left when arm 54 snaps to the right. This action causes blade extension 219 to abut latch portion 225 and move restrainer member 221 to the left, as viewed in FIG. 3. This movement is terminated when the teeth 231 engage the teeth 128 of wheel 126; at this time the contact 46 is held in a position between contacts 39 and 42 so that the defrost heater, the compressor and the fan are all off. As the wheel 126 is rotated the restrainer is revolved counterclockwise about shaft 118. After about 6 to l0 minutes of such angular rotation, extension 219 is released from latch portion 225 so that the contact 46 snaps to contact 39 to start the compressor and fan. In this manner, the desired delay of refrigeration is provided as a function of time.

In the delay mechanism of FIG. 2, the heater 158 can be connected to terminal 40 as shown, because the wheel 126 can be stopped during the defrost cycle since the delay is a function of temperature. Hence, in the delay mechanism of FIG. 2, the timer mechanism can operate either only during compressor operation or all the time.

It is important to appreciate that, while the particular switch mechanism disclosed in FIGS. 2 and 3 has great utility, other switch arrangements can be operated by the temperature or time responsive means disclosed in FIGS. 2 and 3, respectively. For example, it is possible to provide two separate switch blades with separate sets of contacts having normal travel; the delay mechanism then can hold one of the switch blades from complete movement whereas both switches must be closed to start the compressor. However the switch disclosed herein is simpler and smaller. Also, in all forms of the invention, the switch has been illustrated with the switch actuator 54 only stable in one position. The inventive concepts disclosed herein apply equally well to switches in which the switch actuator is stable in two positions.

FIG. 4 illustrates the mechanism disclosed in FIG. 3 applied to any type of mechanism in which any signal operates a switch, and the action of the switch is delayed in either of its two operating directions. In the example shown in FIG. 4, an actuator 240 is operated to the left, as viewed in FIG. 4 by any signal force F,

so that the arm extension 54a causes contact 42 and extension catch 219a to move to the right, and operate in the same manner as described in FIG. 3. The force F could be produced, for example, by a temperature or pressure-responsive bellows or diaphragm, or by manual means, or as a position stop for a traveling element of any machine, etc. Then, when the signal force F is removed, the switch-blade is delayed by catch 219a a predetermined period of time in the manner described in reference to FIG. 3. Also, when force F is removed, the switch arm 54 and actuator are returned to the positions shown in FIG. 4 by the force of spring 53; but the switch-blade does not return to its initial position shown until released by the catch 219a after the timedelay period. In FIG. 4, the heater 158 is connected across the line terminals as shown, so that the bimetal operates wheel 126 continuously.

Referring to FIG. 5, a modified construction is illustrated to provide an action reverse from the action of the form of the invention shown in FIG. 4.

In FIG. 5, a clutch member 242 takes a different form than the clutch member 221 in FIG. 4. The extension catch 219b of the switch blade 217 cooperates with a latch portion 225a to provide the desired action. The pin 118 supports the member 242 in slot 223 to enable rightward and leftward movement of the member to engage or disengage, respectively, with the teeth 128 of the ratchet Wheel 126. The ratchet Wheel in FIG. 5 is caused to revolve in a clockwise direction by the bimetal 150 (in a manner shown in FIG. 1 of the parent application) in order to provide a counterclockwise movement of the clutch member when engaged with the ratchet member in opposition to spring 22711 which also pulls the member in a leftward direction. In operation, when the actuator 240 and arm 54 are moved to the left, as viewed in FIG. 4, the catch 219b abuts the latch portion 225a as shown wherein the spring 53 moves the clutch member 242 to the right into engagement with the teeth of the ratchet member 126. This action stops the contact 46 in a position between the fixed contacts 39 and 42. At the same time, the ratchet wheel rotation causes the latch portion 225a to move downwardly, as viewed in FIG. 5, for a predetermined period of (delay) time until it clears the end of the catch 219b. At this time (at the end of the delay period), two separate actions occur: The irst action is that the contact 46 snaps into abutment with contact 42. In the second action the spring 227a returns the latch member to the position shown in FIG. 5 out of engagement with the ratchet wheel 126. When the actuator and switch arm again return to the position shown (in FIG. 4), the switch blade snaps back to the position shown, so that the rotary effect of spring 227a causes the latch portion 22Sa to return to the position shown in FIG. 5, so that the cycle can be repeated.

In all forms of the present invention, if desired, any other motor timer such as a more expensive electric motor timer with gear reduction may be used in place of the bimetal timer shown herein. In this event, the clutch members 221 or 242 would engage any gear of the gear train to provide a wide range of time delays. Adjustment of the time delay in all forms of the invention may be provided by a rheostat in series with the bimetal heater 158.

What I claim is:

1. In a mechanism including a snap-action device, the combination comprising; two xed abutments, control means including a member reciprocally movable in a predetermined path of travel between said two abutments, actuator means operatively connected to said control means and including means operable to cause said member to snap from one of said abutments to the second of said abutments, and delay means cooperating with said movable member and operable independently of said actuator means to hold and detain said member temporarily in a position between said two abutments.

2. In a mechanism includling a snap-action switch mounted in a housing, the combination of; two iixed abutments mounted on said housing, at least one of said abutments comprising a iixed contact, switching means including a switching contact adapted to abut said fixed contact and reciprocally movable in a predetermined path of travel between said two abutments, switch actuator means operatively connected to said switching means and including spring means operable to cause said switching contact to snap from one of said abutments to the second of said abutments, and delay means cooperating with said movable switching means and including means to hold and detain said movable contact temporarily in a position between said two abutments.

3. In a mechanism including a snap-action switch mounted in a housing, the combination of; two iixed abutments mounted on said housing, at least one of said abutments comprising a iixed contact, switching means including a switching contact adapted to abut said iixed contact and reciprocally movable in a predetermined path of travel between said two abutments, switch actuator means operatively associated with said switching means and including means operable to cause said switching contact to snap from one of `said abutments to the second of said abutments, and delay means cooperating with said movable switching means and automatically operable independently of said actuator means to hold and detain said movable contact temporarily in a position between said two abutments.

`4. In a mechanism including a snap-action electric switch, the combination comprising; two iixed contacts, switching means including a switching contact adapted to abut said xed contacts and reciprocally movable in a predetermined path of travel between said two fixed contacts, switch actuator means operatively connected to said switching means and including snap-action means operable to cause said switching contact to snap from a rst of said ixed contacts to the second of said iixed contacts, said snap-action means including a spring having a portion thereof operatively connected to said switching means at all times, said spring having another portion thereof operatively connected to said actuator means in a manner to cause said snap-action upon a predetermined movement of said actuator means, delay means operatively connected periodically to said movable switching means and including means to hold and detain said movable contact temporarily in a position between said two fixed contacts, and said delay means including means to automatically cause a release of said switching means for enabling said movable contact to snap instantly to one of said ixed contacts.

5. In a control mechanism for delaying operation ofi a device in an electric circuit having a source of electric energy, the combination comprising; a housing, switch means in said circuit and mounted in said housing and including a swingable member to control operation of said device, said swingable member including hinge means at one end thereof cooperating with a tixed portion of said mechanism to provide arcuate movements of the free end of said member, initiating means operatively associated with said switch means to affect operation of said device, said switch means` including fixed contact means mounted on said housing, said swingable member at substantially said free end thereof including movable contact means cooperating with said xed contact means and controlled by said initiating means to regulate said operation of said device in a normal total travel of said movable contact means, and delay means operable independently of said initiating means to hold said swing able member and its said movable contact means in a position between the extremes of said total travel to cause one type of operation of said device, said holding means including means to automatically release said movable contact means to return to one extreme of travel for causing another type of operation of said device.

6. The combination of means defined in claim 4, in which said means included in said delay means for holding said movable contact means detains same for a predetermined period of time, and said release-causing means included in said delay means operates to cause said reelase of said switching means at the termination of said predetermined time period.

7. The combination of means defined in claim 6, and motor-operated timer means cooperating with said delay means to determine said time period, and said delay means being operable independently of said actuator means, and said delay means including clutch means to engage a portion of said timer means for operation thereby to cause initiation of said time period, and said clutch means including means automatically to effect disengagement of said clutch means from said timer means portion as a result of said release of said switching means to cause said termination of said time period.

8. The combination of means defined in claim 6, and motor-operated timer means cooperating with said delay means to determine said time period, said timer means including a lslowly rotating member operated by said motor and having a clutchable portion on substantially the perimeter of said rotating member, and Said delay means including clutch means to cooperate with said timer means, said clutch means including a gripping portion adapted to be moved into engagement with said clutchable portion to initiate said time period and to move out of said engagement with said clutchable portion for tenminating said time period.

9. The combination of means defined in claim 6, and motor-operated timer means cooperating with said delay means to determine said time period, and an electric circuit, and said motor-operated timer means including rotary means and also including movable timer actuating means periodically operated to cause rotation of said rotary means, said timer means including a bimetal element adapted to cause said movements of said movable timer actuating means, electric heating means connected in said electric circuit and mounted near said element to provide electric energy for intermittent heating of said bimetal element for causing reciprocating movements thereof to effect said periodic operation of said movable timer actuating means, switch means in said circuit operated by said bimetal element for controlling said electric heating means to provide said intermittent heating and cooling thereof for effecting said reciprocating movements of said element, and said delay means including clutch means to engage said rotary means for operation thereby to cause initiation of said time period and automatically to disengage from said rotary means to cause said termination of said time period.

10. The combination of means defined in claim 6, and force-producing means operatively associated with said actuator means and including motor-operated timer means to cause said operation of said switch actuator means, and said delay means including clutch means to engage a portion of said timer means for operation thereby to cause initiation of said time period and automatically to disengage from said timer means portion upon said releasing action of said switching means to cause said termination of said time period.

11. In a mechanism including a snapeaction electric switch, the combination of; two fixed contacts, switching means including a switching contact adapted to abut said fixed contacts and reciprocally movable in a predetermined path of travel between said two fixed contacts, switch actuator means operatively connected to said switching means and including snap-action means operable to cause said switching contact to snap from a first of said fixed contacts to the second of said fixed contacts, thermally-operated delay means cooperating with said movable switching means and including means to hold and detain said movable contact temporarily in a position between said two fixed contacts, and said delay means including temperature-sensitive means to cause a release of said switching means for enabling said movable contact to snap instantly to one of said fixed contacts.

12. The combination of means defined in claim 11, and said temperature-sensitive means including a bimetal element responsive to ambient temperature changes, said bimetal element including a latch portion comprising said holding means, said latch portion being adapted to engage said movable switching means when said bimetal element warps in one direction as a result of said ambient temperature attaining one predetermined value, and said latch portion being moved out of said engagement with said movable switching means when said bimetal element warps in a direction reverse from said first-named direction as a result of said ambient temperature attaining a second predetermined value.

13. In a mechanism including a snap-action electric switch mounted in a housing, the combination of; two fixed contacts mounted on said housing, switching means including a switching contact adapted to abut said fixed contacts and reciprocally movable in a predetermined path of travel between said two fixed contacts, switch actuator means always operatively connected to said switching means and including snap-action means operable to cause said switching contact to snap from a first of said fixed contacts to the second of said fixed contacts, delay means cooperating with said movable switching means and including means tot hold and detain said movable contact temporarily in a position between said two fixed contacts, and said delay means including means to automatically cause a release of said switching means for enabling said movable contact to snap instantly to one of said fixed contacts, and force-producing means operatively associated with said switch actuator means to cause operation thereof.

1-4. The combination of means defined in claim 4, and force-producing means operatively associated with said switch actuator means to cause operation thereof, said force-producing means including motor-operated timer means to cause operation of said actuator means after periodic time intervals.

15. The combination of means defined in claim 6, and said switch actuator means including a spring acting on said switching means with a predetermined force, and motor-operated timer means cooperating with said delay means to determine said time period, said timer means including a slowly rotating member operated by said motor and having a plurality of teeth on at least a portion of substantially the perimeter of said rotating member, and said delay means including a clutch element disposed to cooperate with said timer means, said clutch element including a portion having a plurality of teeth adapted to be moved into engagement with said member-teeth as a result of said force of said switch spring upon completion of said first-named operative connection to initiate said time period, said clutch element including means to` cause said release of said switch means after a predetermined travel of said rotating member, and second spring means acting on said clutch element with a force less than said first named spring force and urging said clutch element out of said engagement when said release is effected.

16. The combination of means defined in claim 6, and motor-operated timer means cooperating with said delay means to determine said time period, and an electric crcuit, and said motor-operated timer means including rotary means and also including movable timer-actuating means periodically operated to cause rotation of said rotary means, said timer-actuating means including electric switch means in said circuit, said switch means including a pair of contacts for intermittent` ly opening and closing said circuit, a bimetal element secured at one end to a fixed portion of said machine and its free end movable in an arcuate reciprocating path as said bimetal element warps upon heating and cooling thereof, an electric heater in said circuit for said bimetal element and controlled by said switch means, a swingable element supported substantially parallel to said bimetal element and having one end hingedly connected to a iixed part of said mechanism and its free end disposed for generally reciprocating arcuate movements from one position to another position, a first of said two elements including a generally U-shaped portion near its said free end for movements therewith, the second of said two elements having its free end disposed within said U-shaped portion, said second element near said free end carrying one of said contacts, said first element at one side of said U-shaped portion carrying the other said contact to cooperate with said one contact to comprise said switch means, a leaf-spring having one end in a hinged connection with a fixed portion of said machine and its other end connected to said swingable element at a position to cause said swingable element to snap from one of said positions thereof to said other position for opening said contacts after said bimetal element is warmed by said heater, and to snap back to said one position upon cooling of said bimetal element to close said contacts and again energize said heater to repeat the cycle, continuously.

17. The combination of means defined in claim 6, and motor-operated timer means cooperating with said delay means to determine said time period, and power means adapted to be operatively connected to said switch actuating means for periodic operation thereof after a predetermined time interval, said power means being movable in one direction in relation to said switch actuator means while disconnected therefrom, energy-storing spring means acting on said power means and adapted to be charged with energy by said movement of said power means in said one direction, said timer means including means operatively associated with said power means to cause said energy-storing movements thereof, latch means operatively connected to said power means and said switch actuating means and operatively disconnected therefrom during said charging movement of said power means, said latch means including means adapted to operatively connect said switch actuating means and said power means before said charging movement thereof is completed, release means operated after a predetermined travel of said power means corresponding to said predetermined time interval to release same for enabling the stored energy of said spring means to cause said power means to move in a direction opposite from said first named direction for operating said switch actuating means, and means operatively associated with said latch means for causing same to operatively disconnect said power means and said switch actuating means after same has been actuated for enabling independent action of said switch actuating means until the cycle is repeated.

18. The combination of elements defined in claim '14, and said motor operated timer means including rotary means, and said force-producing means including power means operatively connected to said timer means for actuation thereby to store energy in a slow charging movement thereof, said timer means and said power means including means cooperating to release periodically said stored energy for causing said operation of said switch actuator means, and a source of electric energy in a circuit associated with said mechanism, a heat-responsive bimetal power element operatively associated with said timer means to cause slow rotation of said rotary means, electric heating means mounted near said bimetal element and connected in said electric circuit for heating said element and causing reciprocating movements'thereof to provide a small input power force, switch means in said circuit operated automatically by said element in a continuous repetitive cycle to reduce the energy from said heating means after said element in one position thereof has been heated and to increase the energy from said heating means after said element in a second position thereof has cooled for producing said reciprocating movements and said input force, said bimetal element including means providing a snap-action thereof to delay each movement of said element from one of said positions to the other said position for establishing a predetermined period of time for said cycle, and said rotary means including means for counting the number of said time-cycles to cause slowly said charging movement of said power means and for causing operation of said energy release means after a predetermined number of time cycles corresponding to said time interval, said counting means including ratchet means having a predetermined number of ratchet teeth, ratchet-actuating means operated as a result of said reciprocating movements of said bimetal element and adapted to move said ratchet means at least a portion of its total travel upon one said cycle of said bimetal element to cause said slow charging movement of said power means.

19. A switch delay mechanism including a snap-action device mounted in a housing, the combination comprising; a pair of terminals mounted on said housing each having a xed contact, a contact arm having a contact mounted thereon, said contact arm being pivotally supported on said housing for reciprocal movement between said xed contacts, actuator means pivotally supported on said housing, means operatively connecting said contact arm and said actuator means, said connecting means being operable to cause said arm contact to snap from one to the other of said xed contacts, and delay means cooperating with said contact arm and operable independent- 1y of said actuator means to hold and detain said contact arm temporarily in a position between said two xed contacts.

References Cited UNITED STATES PATENTS 2,333,319 11/1943 Kucera 337-301 X 2,528,766 11/1950 Marcellus 337-301 X 3,172,978 3/1965 Taiiet 337-341 X 2,596,039 5/1952 McConnick 337-301 HIRAM B. GILSON, Primary Examiner U.S. Cl. X.R. 337-341

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