US2312547A - Burner control apparatus - Google Patents

Description

March 2, 1943. c. v. HILDEBRECHT 2,312,547

' BURNER CONTROL APPARATUS Y med Feb. 11, 1942 2 sheets-sheet 1 v March 2, 1943. c. v. HILDEBRECHT BURNER CONTROL APPARATUS Filed Feb. 11, 1942 2 Sheets-Sheet 2 INVENToR,

@@2565 dddeed mail Patented Mar, 2, 1943 BURNER COL APPARATUS Chai-lea V. Hildebrecht, Chicago, lll., assigner to Milwaukee Gas Specialty ompany, Milwaukee, Wis., a corporation ci? Wisconsin Application February il, i942, Serial No. `430,378 Claims. (Cl. 23S- 1) This invention relates, generally, to apparatus for controlling uid flow in conduits, and it has particular relation to improvements in burner control apparatus of the character employing an electromagnet which is effective, when energized, to maintain a valve or other controlling member in open or operating position but which is ineffective to move the valve or other controlling member from closed or safety position to open or operating position.

An illustrative example of such a burner control apparatus is apparatus in which there is an electrical operating circuit for the electromagnet and a thermoelectric generator energized by the heat of a pilot light or other flame for supplying current to the operating circuit.

The present invention may be embodied in a wide variety of constructions for use with a wide variety of devices employing gas or other fuel burners. For purposes of illustration I shall refer to a number of illustrative devices with which the present invention is adapted to be used, but it is to be understood that the invention is not necessarily limited to use with the particular devices herein set forth.

Due to the minute character of the maximum electromotive force that can be generated by the heat of a pilot light or other flame or source of heat ona' thermoelectric generator and the inability of this minute electromotive force to actu-y ate the main shutoff valve or controlling member from closed or'safety position to open or operating position, thermoelectric control and safety shuto devices heretofore have usually required manual cooking or reset means, such as a cocking or reset button, for cooking or resetting the device after each .operation to closed or safety position.

' As a result, these thermoelectric control and safety shutoff devices usually have not been automatic or completely self-operating. For example, if a thermostat or other condition-ressponsive control were employed for opening or disabling the thermoelectric circuit for operation of the valve to closed position at one predetermined temperature or other condition, and

for closing or rendering the thermoelectric circuit operative at another temperature or condicontrol devices heretofore provided, it has been necessary to reset the shutoff valve to open position after the failure of the pilot light or other ilame, and if a thermostat or other conditionresponsive control were employed With such a device it would be necessary to reset the shut oil valve to open position after each closing of such valve under the action of the thermostat or other condition-responsive means.

In that pilot failure usually occurs only infrequently, the matter of resetting the device after the failure ofthe pilot light is not objectionable, but any necessity for resetting the device after each operation of the valve or other controlling member to closed or safety position under the action of the thermostat or other conditionresponsive means presents a. dimcult practical problem.

l am aware of the prior art provisions for eliminating the necessity of manual cooking or reset means, and the necessity of a manual cooking or resetting operation. In these prior art devices however, the main shutoff valve or other controlling member is not only held in open "or operating position by the minute thermoelectromotive force, but is actually moved from closed or safety position to open or operating position through the instrumentality of this minute thermoelectromotive force, which is quite dier yfor example, by the heat of the pilot light or other flame on the thermoelectric generator and, in conjunction therewith, meanstfor automatically operating the shutoff valve or controlling member to closed or safety position, and, if desired,

' to open or operating position under the action of a thermostat or other condition-responsive r control and without releasing the first mentioned means from the position in which it is held by the electromagnet.

Another and more specific object of the invention is to provide in a control system of the class described wherein there is a fluid supply conduit, a valve for controlling the supply of fluid through the conduit, a movable armature operable to control the valve, an electromagnet for the armature, a thermoelectric generator.. connected in circuit with the electromagnet for energizing the electromagnet to hold the armature in attracted position, and reset means for resetting the armaondary circuiti! as willpresently appear. i

ture to attracted position, the combination with such system of condition responsive means and particularly a thermostat operable to close the valve and, if desired, to open the same while the armature remains held in attracted position by the electromagnet.

One of the advantages of the features set forth is the ability with a thermoelectric safety device to secure automatic' on and olf thermostat or other condition responsive control without requiring a resetting operation after each off operation of the thermostat or other condition responsive means and without requiring actual movement of the main shuto valve to open or operating position through the instrumentality of the minute thermoelectromotive force. Y

While the particular structural features by which I obtain a device of the character set forth a are important features within the more specific aspects of the invention, it is to be understood that the precise features shown and described may be varied within'the broader aspects of the invention. j

In order to acquaint those skilled in the art with the manner of constructing and operating a device in accordance with the present invention, I will now describe, in connection with the aecompanying drawings, one illustrative embodiment of the invention.

In the drawings: y

Figure 1 is a front view of a safety switch embodying the present invention, partially in section and with the cover removed and showing the switch in closed position;

Figure 2 is a detail section taken on the line 2-2 of Figure 1;

. Figure 3 is a detail section taken on the line 3-.3 of Figure 2;

Figure 4 is a more or less diagrammatic view showing the switch in side elevation and in con nection with burner apparatus;

Figure 5 is a fragmentary detail view showing the position of the switch actuator and reset means, with the reset member pressed inwardly to cock or reset the device; and l Figure 6 is a view similar to Figure 5 showing the position of the switch actuator and reset" means with the switch in open position and the reset member and reset stem released.

In Figure 4 of the drawings, a gas or other fuel burner of any suitable or preferred type is conventionally illustrated at I0. The burner I may be the burner of a room or space heater, water heater, fioor furnace, gas range, or any other burner. A gas or other fuel supply pipe I I leads to the burner Il! for the delivery of gas or other fuel theretofor example, through "a mixing chamber (not shown) to which air is admitted in the usual way as well understood in the art.

A power actuated or electroresponsive valve I2, such as a solenoid or motor valve, is interposed in the fuel supply pipe I. The valve I2 shown as -oomprising a valve body I3 and a hood I4 having suitable power operated valve actuating means therein. A step-down transformer I supplies power for the operationl of the valve I2. 'I'his transformer comprises a line voltage primary I6 and a low voltage secondary Il. 'Ihe primary I8 is connected to line wires I8 leading to any suitable source of current or power (not shown).

vThe valve actuating means for the valve I2 is connected into the secondary circuit I9. The safety switch and thermostat or other condition responsive control is also connected into-the sec- For purposes of illustration it may be assumed that the valve I2 is of a character to be actuated to open position by closing vof the circuit I9 and to be held in open position to supply fuel or operative energy to the burner I0 as long as the circuit I9 is closed. The valve I2 may have spring means, orother suitable means, for actuating the valve to closed position to shut oif the supplyof fuel to the burner II! when the `circuit I9 is opened or otherwise disabled.

'The safety switchpcr se selected for illustration is similar to that more fully disclosed in the -copending application of Harold A. Mantz, Serial No. 394,601, filed May 22, 1941, but it is to be understood that the construction and operation of the safety switch part of the combined safety and thermostat or other condition responsive control of the present invention may, within the broader aspects of the invention, be of any other suitable or preferred form.

The safety switch and thermostat control is shown as located within a. housing 2U. The opposite ends of the back wall of the housing are turned in to form end walls 2I, and, at the opposite sides of the'backwall, are inturned flanges 22. The cover 23, which may be of generally U-shaped cross section, fitsI over the inturned end walls 2i with the inner marginal edges of the sides of the cover fitting over the flanges 22. Slots 2I, opening inwardly from the inner marginal edges of the side wallsl of the cover iitY over the Shanks of screws which have threaded engagement in the side flanges 22. The screws 2i are adapted to be tightened to secure the cover in place von the base of the housing, and to be loosened to permit removal of -the cover. a 'I'he screwsl and slots 24 may be positioned at dlf` ferent distances from the opposite ends of the device to assure proper mounting of the cover 23.

Thefront wall of the cover 23 has an opening 28, shown in dotted lines in Figure 4, through which an indicator is adapted to be viewed to indicate the position of the switch as will hereinafter appear.

An actuator or reset member operates between open and closed positions by rectilinear v movement through an opening 3| in the adjacent end wall 2I of the housing. The outer end of the actuator member 3l! is provided withan operatingbutton 32. The actuator member 30 is shown as comprising a pair of actuator member partsforming a forkat the inner end of the actuator member and secured together outwardly of the forked'inner end. A pin 24, secured in the' ac. f

tuator member 30 outwardly of its forked inner end, cooperates with the adjacent end wall 2| to limit outward movement of the actuator member.

'I'he actuator member I! is yieldingly retained in its outwardly projected position as shown in Figures l and 6 and upon release of the button 32, as will presently appear, is returned to this youtwardly projected position by a coiled return spring 38. This spring 2l is shown as connected between the inner end of the actuator member ll, at 31,-and a spring anchoring lug I8 pressed inglardly from the adjacent end wall 2I of the hous- A reset member III extends between the sides of the .forked inner end of the actuator member Il. The inner end of the member 40 has a bifurcation or lslot at 4I within which a cam lever 42 is pivoted on a pin 4l. the opposite ends of which .pin extend into longitudinal slots M in the opposite sides of the forked innervend of the actuator member Il. The cam lever 42 has a cam slot minals 82.

asian? 45 through which extends a pin 40, the opposite ends of which are secured in the opposite sides of the forked inner end of the actuator member 3B.

The cam lever 42 has secured thereto, for example, at i8, an overtravel spring arm 49 for actuating the switch to closed position. I'he lever 62 also carries a iiag or indicator member 50. This indicator member 50 has on and ofl!" markings thereon as shown, or is provided with colored cr other appropriately marked portions for indicating through the opening 28 in the switch cover 23 the position cf the switch, as will presently appear.

The means for holding the reset member B in the position shown in Figure 1, so that the switch will close when the actuator member 30 is released following lts inward resetting movement lected for illustration comprises a magnet frame B secured, for example, to a terminal bushing 51 in the manner more fully disclosed in the copending application of Clarence Wantz, Serial No. 328.923. filed April 10, 1940. The coil of the electromagnet is wound around the legs o! the magnet frame 5B, The bushing 51 is shown as extending through an opening 59 in the adjacent end wall 2i and is externally threaded for threaded engagement at 80 with a nut 62 by means of which the bushing is clamped in place in the end wall 2| of the switch housing.

The electromagnet has an armature El attached at l5 to the adjacent end of a stem $6, if desired, in a manner to permit self-accommodation of the armature, when in attracted position, to the pole ends of the magnet frame t6. The electromagnet and amature are enclosed within a cup 68. The stem B5 extends for reciprocatory movement through an opening 69 in the inner end of the cup 88. The opening 69 is sealed by sui",- able sealing material such as a leather washer, felt packing or the like, as indicated at Ii, interposed between the inner end of the cup 68 and a spring seating disc 12. The end of the stem B8 opposite the end on which the amature 54 is mounted is secured, for example, by a pin 13 to the lxdjacent end of the reset member 40. A coiled spring 14, interposed between the spring seating disc 12 and a spring seat member l5, actuate-s the armature 6B to retracted position and the reset stem 6B and reset member to the position shown in Figure 6 when the eiectromagnot is deenergized, for example, upon extinguishment of the ilame to which the device is responsive.

The particular switch selected for illustration is indicated in its entirety at I8 and is shown as comprisinga pair of contacts or contact pins 30 positioned in spaced relation and suitably insulated from each other and the other parts-oi the device. The contact pins 86 are connected to ter- The conductors I8 o! the circuit for the valve I2,4 which conductors are insulated at B4, enter the housing through an insulating grommet 85. One o1' the conductors I9 is connected to the terminal 'l2 for one switchv pin 8B, and the other conductor I9 is connected to the other terminal 82 for the other switch pin R0.

The switch stem 88 has rectilinearV sliding movement in the insulating base or block of the switch 1I, with the outer end of the stem `in position for cooperation with the switch operating spring arm I9 onthe cam lever 42. Within the switch block the reduced inner end of the stem a8 passes through a bridging contact plate 90. A coiled spring 82 surrounding thereduced inner end of the stem 88 and interposed between 'the contact plate 90 and an abutment 93 on, or forming a part oi', the switch base yieldingly urges the plate 9i) out of bridging contact with the contacts S0 to open the circuit I9. By engagement of the contact plate 9@ with the shoulder Sl on the stem 58, the spring 82 also yieldingly urges the stem B to its outwardly projected position as shown in Figure 6. Stop. means (not shown) may be provided for limiting the outward movement of the switch pin B8 under the action of the spring 52.

The pilot burner 95. which is located in juxtaposition to the main burner I@ to maintain av pilot light for lighting the' main burner, is supplied with gaseous fuel by a pilot supply pipe 96. The pilot supply pipe 96 may be connected with .the main fuel supply pipe I I anterior of the valve I2, or it may be supplied with fuel for delivery to the pilot burner in any other desired manner.

A thermoelectric generator, in theform -of a thermocouple indicated at 98. is placed in position so that the hot junction 89 thereof will be heated by the pilot flame as long as the pilot name is burning. The construction of the thermocouple may be similar to that more fully disclosed in Oscar J. Leins Patent No. 2,126,584, granted August 9, 1938, or a thermopile orany other form of thermoelectric generator may be employed.

For the purpose of4 the present description suiiice it to state that the particularl thermocouple selected for illustration comprises an' outer tubular thermocouple member and an inner metallic thermocouple member of different thermoelectric characteristics. The inner thermocouple member is joined at one end to the outer end of the outer thermocouple member to i'orm the thermojunction 99 which is placed in position to be heated by the pilot flame. An innervlead conductor |00 is joined to the inner thermocouple member to form an internal thermojunction I!i2, and an outer tubular lead conductor w3 is connected to the outer thermocouple member, for instance through a sleeve, to form a third thermoiunction. The lead conductors are preferably of flexible character so as to be readily bent to insure neat installations. The inner lead conductor Iii is insulated from the outer lead conductor it, for instance, by a wrapping of insulation idd on the inner lead conductor.

Aquick detachable or removable connection is preferably provided between the coil 58 of the electromagnet and the ends of the leads |00 and It opposite the ends which are connected to the thermocouple. This removable lead connection may be of the form disclosed in the copending application of Clarence Wantz hereinbefore identified and as Illustrated in that form, although it maybe of any other suitable or preferred form. Sutiice it to state that the inner lead |00 has a connector cone Idd which seats in the correspondingly recessed outer end of the terminal tip i and is clamped in contact'therewith by a connector sleeve IN. nie adjacent end of the outer tubular lead conductor ID3 is connected in circuit with one side of the coil 58 through the bushing Bland the other side oi' the coil is connected to the terminal tip IUI, the parts being suitably insulated as shown.

To start the operation of the system shown in following inward movement of the actuator member 30 moves the reset stem 55 with it in the same dithe inner ends of the slots 44. Asa result, the f rection until' the armature 54 isV cocked or set into vattracted position against the pole ends of the magnet frame 55.

The pilot burner 95 is lighted, or, having been lighted, heats thethermoelectric generator, and the actuator member 50 is held pressed inwardly until the heat of the pilot llame on the thermoelectric generator has energized the electromagnet sufficiently so that it will holdl the armature 54 attracted thereto.

When the electromagnet is energized suillcient- 1y to hold the armature 64 in attracted position, the actuator member 30 is released and the reset stem 59 and reset member 40 remain in cocked position, holding the pivot 43 for the cam lever 42 in the position shown in Figure l5. The switch operating spring arm 49 assumes the position shown in Figure 5 when the actuator member 30 is pressed inwardly. Then, with the amature 95 held attracted to the magnet frame 59, thereby holding the pivot 43 for the cam lever 42 in 'the position shown in Figure 5, when the actuator member 30 is released the outward movement of the actuator member 3l, under the action of the spring 35, causes the pin 45, by its outward movement in the cam slot 45, to swing the arm 49 in a counterclockwise direction (Figures 1 and 5) about the pivot 43 from the position shown in Figure 5 to the position shown in Figure 1. The arm 49, by cooperation with the outer end of the vswitch pin 95 in this'movement, moves the contact plate 90 inwardly against the action of the spring 92 and into bridging contact with the contacts 80 to close the circuit I9. The circuit is thus closed not by the inward movement of l of the contact plate 99 with the contacts Il which tensions4 the spring arm 49 to assure firm and tensioned' contact.

If the pilot burner'is'not lighted to produce the thermoeiectric current for holding the armature 34 in attracted position upon setting the same to that position by the actuator member 30,

the armature 54v and reset stem 5l 'will move to retracted position upon release lof the actuator member 39, the spring 92 at this time `maintaining the switch plate in open position.

If, after the parts arev set as shown in Figure 1 and the pilot burner is lighted to hold the parts Vin the position shown in this -ilgure, the pilot burner is extinguished, the armature 54 is released and theA spring 74 then operates to move the armature to retracted position. The cam lever 42 moves outwardly with the movement of the reset stem 95 to released position through the pin connection at 43, and the cam slot 45,

cooperating with the pin 45 by'this movement ofv the cam lever 42 relative to the actuator member 30, swings the arm 49 ina clockwise direction about the pivot 43 to the position shown in Figure 6. `This releases the switch pin 39, and the spring' 92 separates the contactplate 9|| from the contacts 80. This opensA or interrupts the circuit i9, and the valve I2 operates to closed position to shut off the supply of fuel to the main burner.

When the armature is in retracted position with the actuator member 30 in released position as shown in Figure 6, the oil marking on the indicator arm is positioned to be viewed through the opening 26 in'the cover of the housing to indicate that the switch is o When the armature is in attracted position and the actuator member 30 is in its outwardly projected position as shown in Figure 1, the onfmarking on the indicator arm 50 is positioned to be viewed through the opening 25 to indicate that the switch is .on or closed.

The thermostat control is shown for purposes of illustration as comprising a bimetallic element of helical form. It is to be understood that any other suitable or preferred form'oi' thermostat may be employed, 'and that, if necessary or desired, the device may be modified for use withv other forms of thermostats-for example, ofthe bimetallic arm type, bimetallic coil type, bellows l' type, or any other type for use with room or space heaters, or for use with hot water heaters, or as a limit control or otherwise as desired.

It is to be further understood that within at least certain aspects of the invention, condition responsive controls otherthan thermostat con trois may be used in place ofthe .thermostat Y control.

The bimetallic element '|25, as shown for purposes of illustration, surrounds a shaft |25 Jour-f The end of the shaft |26 opposite the end which is secured to the bimetallic element |25 extends into the housing 20 and carries, for

turning movement therewith, a tripping lever |35. extended free outer end of the spring arm 49, or otherwise with this arm as suitable or desired. l

Whenthe selected temperature is reached as determined by the setting ofthe pointer |32 along the temperature markings onV the dial |34, the

bimetallic element |25 turns the shaft |26, and

thereby the arm |35, in a' counterclockwise direction from the position shownV in Figure 1. Assuming that the armature 54 is held inattracted position by the energization of the electromagnet by the heat of the fiamelon the thermoelectric generator andthat the actuator member 301s in released position and the switch closed as shown in Figure 1, this counterclockwise movementof the tripping lever |35 forces the spring'arm 49 f outwardly away from the switch operating member or pin 88. The spring arm |35 is moved, for example, to the position indicated generally in dotted lines in Figure l, and as a result, the' The tripping lever |35 cooperates with the switch opens under the action of the spring 82 with a resulting closing of the valve I2 to shut of! the supply of fuel to the main burner.

It is to be noted that the closing of the valve i2 under the action of the thermostat is eiiected through at least a part of the mechanism through which the valve is maintained open bythe attractionof the armature 64 to the electromag-l net. And what is particularly important is the fact that this thermostat closing of the valve is accomplished without releasing the armature from the electromagnet, or in other words, while the amature $4 remains held in attracted 4position by the electromagnet.

when the temperature to which the thermostat is responsive drops below the temperature for which the device is set, the tripping lever |35 is turned in a clockwise direction (Figure l) to position to permit the spring arm 49-assuming, of course, that the armature is still in attracted position-to move to the position in which it closes the switch through the pin or switch operating member 88, the arm 49 thereupon maintaining rthe switch in closed position as long as the thermoelectric generator is heated by the pilot light on other name.

From the foregoing it will -be apparent that thearmature 65 is released only upon extinguishment of the pilot light or other name and that, therefore, a resetting of the device is required only after the valve is closed by extinguishment of the pilot llame. The thermostat or condition responsive control operates through a part of the mechanism through which the valve is maintained open by the armature when the amature is in attracted position and the on and "oiT operation of the thermostat control is accomplishedwithout releasing the armature, or, 'in other words, while the armature is held in attracted position by the electromagnet. As a result, the device ls fully self-operating or automatic except when it operates to safety position upon extinguishment of the pilot light, which Y usually occurs infrequently.

The switch or switch contact plate 90 is illustrative of a controlling member. It is to be understood that this controlling member may be in the form of a valve member held in open position by the spring arm 48 'and operable to closed position when the yspring arm is released by the thermostat control or by the release of the armature upon extinguishment of the pilot light. It is to be further understood 'that the arm 49,

instead of being in the form oi' a spring arm,

may be in the form of a rigid arm pivoted to the cam lever 42 and held in operating position and returned to that position by a tension spring connected between the arm 49 and another suitable part. In the case of a rigid pivoted arm. suitable abutment means would be provided for limiting the pivotal action of the arm to hold it in its proper position.

The embodiment of the invention shown in the drawings is for illustrative purposes only, and it is to be expressly understood that saidv drawings and the accompanying specification are not to be construed as a definition of the limits or scope of the invention, reference being had to thev appended claims for that purpose.

I claim:

l. In combination, a fluid supply pipe, a controlling member having an operating position for the flow of iiuid through said pipeV and a safety position shutting oir the flow of fluid through said pipe, a reset member mounted iorl movement to reset and released positions, an actuator member mounted or movement to resetting and released positions and cooperable with said reset member, when same is inv released position, to reset said reset member to reset position by movement of said actuator member from released position to reset position, means for holding said reset member in reset position, an operating arm for actuating said controlling member to operating position by cooperation of said actuator member therewith upon movement of said actuator member from resetting position to released position and only when said reset member is heldin reset position, means for holding the parts in cooperative relationship, and condition responsive means having mechanical cooperation vwith said operating arm for releasing, by mechanical actuation of said arm by said condition responsive means, said controlling member for movement to safety position while said reset member is held in reset'position.

2. In combination, a uid supply pipe, a controlling member having an operating position for the flow of iluid through said pipe and a safety position shutting oil the ilow of fluid through said pipe, a reset member mounted for movement to reset and released positions, Van actuator member mounted for movement to resetting and released positions and cooperable with said reset member, when same is in released position, to reset said reset member to reset position by movement of said actuator member from released position to reset position, means for holding said reset member in reset position, an operating arm for actuating said controlling member to operating position by cooperation of said actuator member therewith upon movement of said actuator member from resetting position to released position and only when said reset member is held in reset position, means for'holding the parts in coopera-' for movement to safety position while said reset member is held in reset position.

3. In combination, a huid supply pipe; a controlling member having an operating position for .the ow of uid through said pipe and a safety position shutting oi the flow of duid through said pipe, a reset member mounted for rectilinear movement. to reset and released positions, an actuator member mounted for rectilinear movement to resetting and released positions and ccoperable with said reset member, when same is in released position, to reset said reset member to reset position by movement of said actuator member from released position to reset position, means for holding said reset member in reset position, an operating arm for actuating said controlling member to operating position by cooperation oi said actuator member therewith upon movement of said actuator member from resetting position to released position and only when 4said reset member is held in reset position, means for holding the parts in cooperative relationship, and condition responsive means having mechanical cooperation with said operating arm for releasing, by mechanical actuation of said -arm by said condition responsive means, said controlling member for movement to safety position while said reset member is held in reset position. l

4. In arswitch of the class described, in combination, a reset member mounted for movement to reset and released positions, an actuator member mounted for movement to resetting and released positions and cooperable with said reset member, whensame is in released position, to reset said reset member to reset position by the movement of said actuator member from released position to reset position, means for holding said reset member in reset position, switch means, a switch operating member actuated to position closing said switch means by cooperation with said actuator member upon movement of Asaid actuator member from resetting position to released position only when said reset memberis held in reset position, means for holding the parts in cooperative relationship, and condition responsive means having mechanical cooperation with said operating arm for releasing, by mel chanical actuation of said arm by said condition responsive means, said switch means for movement to open position while said reset member 1s held in reset position.

5. In a switch of the class described, in combination, a reset member mounted forrectilinear movement to reset and released positions, an

Aactuator member mounted for rectilinear movement to resetting and released positions and cooperable with said reset member, when same is in released position, to reset said reset member to reset position by the movement of said actuator member.from released position to reset position, means for holding said reset member in reset position, switch means, a switch operating member actuated to position closing said switch means by cooperation with said actuator member upon i movement of said actuator member from resetting position to released position only when said reset member is held in reset position, means for holding the parts in cooperative relationship, and condition responsive means having mechanical cooperation with said' switch operating member for releasing, by mechanical actuation o1 said switch operating member by said condition responsivemeans, said switch means for movement to open position while said reset member is held reset position, means for holding said reset member in reset position, a'cam lever pivoted on said reset member, cam means on said actuatormember for cooperation with said lever, an over-travel spring operating arm carried by said cam lever for actuating said controlling member to operating position by movement of said actuator member yfrom resetting position to released posirtion and only when said reset member is held in reset position, means for holding the Vparts in cooperative relationship, and condition responsive means having mechanical cooperation with said overtravel spring operating arm for releasing, by.

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mechanical actuation of said arm by said condition responsive means, said controlling member for movement Ito safety position while said -reset member is held in reset position.

7. In combination, a iluidV supply pipe, a controlling member having an operatingposition for the flow of fluid through said pipe and a safety position shutting oi the ilow of fluid through said pipe, a reset member mounted for movement to reset and released positions,`an actuator member mounted for movement to resetting and released positions and cooperable with said reset member, when samev is in released position, to reset said reset member to reset position by movementof said actuator member from released position .-,to reset position, means for holding said reset member in reset position, a cam lever pivoted on said reset member, cam means on said actuator memy ber for cooperation with said lever, an overtravel spring operating armcarried by said cam lever for actuating said controlling Vmember to operating f position by movement of said actuator member from resetting position to released position and only when said reset member is held in reset posi'- tion, means for holding the parts in cooperative relationship, an indicator arm on said cam lever for indicating by the position of the cam lever the position of said controlling member, and condition responsive means having mechanical cooperation with said overtravel spring operating arm for releasing, by mechanical actuation of said arm' by said condition responsive means, said controlling member for movement to safety position while said reset member is held in reset position.

8. In combination, a fluid suppIy'pipe, a controlling member having an operating position for the flow of fluid through said pipe Land a safety position shutting oi! the flow of -fiuid through said pipe, a reset member mounted for movement to reset and released positions, an actuator member mounted for movement to resetting and released positions and cooperable with said reset member, when same is in released position, to reset said reset member to reset position by movement of said actuator member from lreleased position to reset position, meansfor holding said reset meml'oer in reset position, a camlever pivoted to said reset member and having a cam slot therein, a

cam 'pin carried .by said actuator member and i engageable in said cam slot for swinging said lcam lever in vone direction about its pivot on said resetv member upon movement of the actuator member to released position with said reset member held in reset position and swinging said cam lever in a counterdirection upon movement of said reset Amember'to releasedvposition, means for holding said parts in cooperative relationship, and "'condition responsive means having mechanical cooperation with said cam lever for releasing, by mechanical actuation of said lever `by said condition` responsive means, said controlling member for movement to safety position while said reset v member is held in reset position.

.9. In combination, a iiuid supply pipe, a controlling member having an operating positionior the flow of iluid throughsaid pipe and a safety Vwith said reset member, when same is in released position, to reset said reset member to reset position by movement of said actuator member from released position to reset position, means for holding said reset member in reset position, a cam lever pivoted to said reset member and having-a cam slot therein, a cam pin carried by said actuator member and engageable in said cam slot for swinging said cam lever in one direction about its pivot on said reset member upon movement of the actuator member to released position with said reset member heid in reset position and swinging said cam lever in a counterdirection upon movement of said reset member to released position, means for holding said parte in cooperative relationship, and condition responsive means having mechanical cooperation with said cam lever for releasing, by mechanical actuation of said cam lever by said condition responsive means, said ontrolling member for movement to safety position while said reset member is held in reset position.

lo. In a switch of the class described, in combination, switch means, a reset member mounted for movement to reset and released positions, an .eaiuator member mounted for movement to resetting and released positions and cooperable with said reset member. whenA same is in released position, to reset said reset member to reset position by movement of said actuator member` from released position to reset position, means for holding said reset member in reset position, an operating arm for actuating said switch means to closed position by cooperation of said actuator member therewith upon movement of said actuator member from resettingposition to released position and only when said reset member is held in reset position, said switch means being operable to open position upon movement of said reset member to released position with said actuator member in released position, means for holding the parts in cooperative relationship, and condition responsive means having mechanical cooperation with said operating arm for releasing, by mechanical actuation of said arm by said condition responsive means, said switch means for movement to open position while said reset mem ber is heldin reset position.

CHARLES V. I-IILDEBRECHT.

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