US2942478A

US2942478A - Control device

Info

Publication number: US2942478A
Application number: US620322A
Authority: US
Inventors: Joseph L Deverse; Russell B Matthews
Original assignee: Baso Inc
Current assignee: Baso Inc
Priority date: 1956-11-05
Filing date: 1956-11-05
Publication date: 1960-06-28
Anticipated expiration: 1977-06-28

Description

war-

III-- June 28, 1960 Filed Nov. 5, 1956 J. L. DEVERSE ETAL 2,942,478

CONTROL DEVICE 3 Sheets-Sheet 1 June 28, 1960 J. L. DEVERSE ETAL 2,

CONTROL DEVICE Filed Nov. 5, 1956' v 3 Sheets-Sheet 2 INVENTORS Joseph L. Deverse Russ e]! 'B. M11758 June 28, 1960 Filed Nov. 5, 1956 ll L 5 ll J. L. DEVERSE ET AL CONTROL DEVICE 3 Sheets-Sheet 3 mmvrozzs Joseph L. Deverse Ram-fig B. Mahh ea:

Cl'ff gs U d-Sta s 2w 2,942,478 coNrnoL DEVICE Joseph L. Deverse and Russell B. Matthews, Milwaukee,

Wis., assignors to Baso Inc., Milwaukee, Wis., a corporation of Wisconsin Filed Nov. s, 71956, Ser. Naszasza t '8 Claims. cl.14-2

larly to an improved combination ignition and fuel conj- 2 ofi pilot fuel valve, a manual pilot fuel valve and filter means for the pilot burner fuel supply, said device also having meanstherein forselectively latching the safety shut-off pilot valve in open position to render said valve non-responsive to pilot outage as desired, thereby pro vidinga single control device which is usable in either 100% shut off or non-100% shut-01f applications, while in the field. v

A further object of the invention. is to provide a de-' retaining manual control and filtering of the fuel supply to the pilot burner. in each application.

A further object of the invention is to provide a device of the type aforementioned having a safety shut-off means as a tfirst major component and a reset means'as a second major component, and'having quick detachable means fouoperatively connecting said com ponents to thereby facilitate initial assembly of the de-' vice andquick replacementof either of said components vice that is sturdy and compact inconstruction, is easily. fabricated and assembled, and is otherwisewell adapted for the purposes for which it was designed.

device having improved reset'means operatively associat I ed with said electromagnetic members and said controlling member and including means for indicating the relative positions of said electromagnetic members and the posi tion of said controllingxmemberi";

A more specific object of-the 'invention'is to provide a device of the type aforementioned Wherein'the means for ind-icatingthe relative positions of said electromagnetic members takes the form of inner and-outer coaxial resetmembers, the inner of said members having an operating position retracted within said outer member and in which position it is disposed when said electromagnetic members are coupled, said inner member also being movable on release of 'said coupled members to a release or shut-off indicating position wherein a portion thereof projects from said outer member to afford areadily visible indicationtof such release and} of-the resultant "shut off of the fuel flow controlled by said device. I

Another and more specific object of the invention is to provide in a device of the aforementioned character,

a secondary or pilot fuel valveas wellas means for con- 1 trolling main burner fuel flow, said pilot fuel valvehav- 1 ing a closed position and having an open position to which it is moved by the resetting movement of the reset means and in which it is held by coupling of said electromagnetic members, saiddevice also including switch means in the'energizing circuit of an igniter for said pilot fuel, said switch means being actuatable by "said reset means during a resetting operation to effect ignition of the pilot burner fuel following opening of the pilot fuel valve during the reset movement.

A further object of the invention'is to providea device of the aforementioned general characteristics wherein there is means to prevent a reset motion of the reset means when the electromagnetic membersare coupled to The novel features which are characteristic of the inventionare set forthwith particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof will best be understood by the following descriptionof the specific embodimentwhen read; in; connection -with the accompanying drawings, in which: I t

Figure 1 is a sectional'viewof an embodiment of the invention shown in a control system for fluid fuel burning apparatus, partsof said apparatus being shown semidi'agrammatically and the partsof the control device being shown in o position; i a a 7 j Figure 2is a framentary sectional view of a portion of the embodiment shown in Figure 1 indicating the relative positions of parts ;of=the device during a resetting operation, other partsof the device and of the apparatus being shown semi-diagrammatically; V I Figure 3 is a fragmentary sectional view similar to Figure 2showing the relative positions of the parts in operative or on position following a successful resetting and ignition'operation;

Figure 4 is a right -hand end view of the device shown in Figure 1, parts being broken away and shown in section; I 'J Figure S is a perspective view of one of the members used in the device depictedtin-Figures 1 through 4 for connecting the safety shut-off means component with the reset means component; and I Figure 6 is a perspective view of one of the members used in the device depicted inFiguresl through '4 for selectively latching the pilot burner safety shut-olfvalve -or space'heater, water heater, floor furnace, gas range thereby preventunnecessary energization of the igniter circuit tending to shorten the useful life thereof, and also preventing unnecessary interruption of thefuel flow to the main burner. I Z l A further object of the invention'is to provide a unitary device of the above character havin'g'a safety "shutor any other burner." A gas or other fuel supply pipe V I v 30 leads to theburner 12, and'a power actuated electroresponsive valve 31 ,suchas a solenoid or other electroresponsive motor valve as suitable or desired is interposed in the fuel supply pipe 30 for control of the fuel flow to burner 12., A room thermostat 40 thermostat ically controls the valve 31 in the usual manner.

'A pilot burner 11 is disposed in ignition relation jacent the main burner 12 and is supplied with fuel through Patented June 28, 1960 other fuel burner of any 3 a conduit 27. Electric ignition means which may take the form of a glow coil 9 is disposed in igniting relation to the pilot burner 11, and a thermoelectric generator 46 is positioned to have its hot junction subject to the heat of burning fuel at the pilot burner for a purpose which will become apparent hereinafter.

Means for controlling the fuel flow to and ignition of the main and

pilot burners

11 and 12 is provided by a unitary control device. which may be disposedremotely from said burners. The unitary control device 10 (Figure 1) contains the following: safety shut-01f means 48 'responsive to pilot burner outage and comprising a first major component, first control or switch means 14 for controlling the fuel flow to the main burner, means including third control or valve means 22. and manual valve 24 for controlling the fuel flow to the pilot burner, second control or switch: means 15'for actuating the ignition means for the pilot burner, and. reset means 18 comprising a second major component and' operable for resetting the safety shut-off means and actuating the aforementioned control means, said reset means including indi cating means for indicating the status ofthe above named control means and of the safety sh11t=oif means 48' as shall later be explained; V

The main burner flow control switch nreans14 is fixedly disposed within a casing 13 of the. control device lilto be. actuated by the reset'means 18 and the safety shut-off means 48 through a pivotallymounted lever 70 as shall be more apparent later. The switch means 14 controls valve. 31 and maybe biased toward a circuit completing position by suitable means such as a' spring 14a. The switch means 14 is connected to the power unit of valve 31 and to a suitable source 32 (as shown schematically in Figures 2 and 3) by

conductors

33, 34, 35 and 36. For purposes of illustration, it may be assumed that the valve 31 is of the character that when the thermostat 40 is calling for heat, the valve 31 will' be actuated to open position by the closing of switch means 14 in the. circuit 33 through 36 and will be held in open position to supply fuel to burner 12 as long as said circuit is closed.

As aforementioned; the control device 10 contains pilot burner control means and is connected to the pilot'supply The switch means 15 for energizing igniter glow coil 9 to thereby ignite the pilot burner 11, as shown schematically in Figures 1 and 2, may be connected to the glow coil 9 and the electrical source 32 through suitable conductors such as 33, 41 and 42, a ballast resistor 43 and

conductors

44 and 36. The ballast resistor 43 located within the device 10 (as shown in Figure 1) and in the aforementioned circuit to the igniter 9, compensates for the change in the resistance of the glow coil when it is energized as is well understood in the art. The switch means 15 may be of the type that is biased toward a closed or circuit completing position by suitable means such as spring 15a, and as will become more apparent later, the

7 switch 15 is actuated between controlling positions by the reset means. 18 which actuation is translated to the switch means: by reciprocatory movement of a switch pin 15b. p

The safety shut-off means 48 is mounted on a wall of casing 13 and comprises a generally U-shaped magnet armature 52 is disposed within: the casing '50: for movement to attracted andretracted: positions with: respect to the magnet core 49: An energizing-coil'51 may be disposed on core 49, and is connected to the thermoelectric generator 46' by a coaxial cable47 whereby when the generator 46 is' heated and coil 51 is energized the magnet is adapted to hold armature 52 in attracted'relation when the latter is moved thereto.

An armature stem 53 is fixedly attached to ma ture 52 and extends outwardlyof the casing 50 to and i through a generally cup-shaped member 54 which is n 56. having an annular stop membern56a disposed therepipe 27 to control the fuel flow therethrough. The conwith an inlet connection 27a andoutlet connection 271", and

having connecting passages 27b; 27c, 27d, and. 276. The path of pilot fuel flow through casing 13' is from the inlet connection 27a successively throughpa'ssage 27b, the filter 21, passage 27c, valve 22, passage 27d, valve 24, and passage 27a to the outlet connection 27;. As shown; the poppet valve 22 is formed with a stem 22a which engages a pivotally mounted lever 75,. said 'valve'being biased toward a closed position by suitable means such as spring t 28. Under certain conditions,.however, valve 22 may be held in open position against said bias by condition responsive safety shut-01f means 48 and by reset means 18 through said lever 75, in a manner to be hereinafter explained. Latch means 89 (shown most clearlyin Figures I- and 6) may also be provided to latch pilot fuel'valve22 in open position and'thereby render said valve non-responsive to the safety shut-oif means 48 and' to reset means in which abuts the inner bottom surface ofthe cupshaped member 54. Biasing; means such as spring 57 may be disposed surroundingly to the armature stem 53, with one. end abutting the end of tubular casing 50 and the. other end engaging the outer undersurface of the cup-shaped member 54 to bias the latter against stop member 56a as shown. in Figures'l to 3. It isto be noted that arrangement afiords a bias of the magnet 49 and armature 52 towards aseparated relation and also affords a lost motion connection of the cupshaped member S4relativeto thearmature stem 53, i.e., cup-shaped member 54 may be moved downwardly with respect to the armature stem to expose the groove 55 for quick detachment purposes as shall be explained more fully later. The outer upper surface of the cupshaped member 54 is formed with an annular camsurface 54b which is adapted to engage the pivotally mounted pivot valve lever 75 moving the latter upon engagement therewith to open valve 22 against the bias of'spning 28 as shall become apparent.

Special attention is directed to the fact that the distance between the armature 52 and the core 49 is preferably so great when said armature and magnet are in separated relation (as shown in Figure 1), that even when magnet" 49 is energized, it has insuflicient attractive force to move the armature 52 from its retracted position 18. The latch means 89 may take the form of an elo'ngated spring strip 90 one end of which islfixedly mounted against the bias of spring 57.

Means for resetting the armature 52 toward attracted relation with. a magnet 49 is provided by the concentric reset means indicated generally by the numeral 18. As shall become apparent during the description of the operation, the reset means 18 also affords during resetting actuation of valve 22 for pilot burner fuel flow, actuation of switch means 15 for ignition of'the pilot burner fuel, and actuation of switch means "14 preventing operation of the main burner flow control means during resetting. In addition, the reset means 18 affords means for indieating the status of components of the device after the 13b and forms a stop shoulder for purposes hereinafter appearing. V l p Reset means 18 comprises a pair of or first andsecond relatively movable concentric reset members indicated generally by the numbers 60 and 61 coaxially disposed within bores 13b and 13s. The outer reset member 61 may be formed of two portions 61a and 61b which are rigidly attached at 610, the general appearance of member 61 being that of asleeve. =Portion 61b is formedwith an axial bore 61d and portion 61a is formed with larger axial bore 61a. The lower end of portion 61b may be formedlwith a, counterbore 61f which together with bore 61d defines a stop shoulder 61g. The inner end of portion 61b is formed with a portion 61h of enlarged outer diameter, forming an annular stop shoulder -61i which overlaps and coacts with stop shoulder 13a to limit the outward movement of member 61. Portion 61g terminates in an annular inner end surface 61k, and the junction of said end surface with the peripheral surface of the enlarged portion 61h is preferably relatively sharp, rather thanrounded, for purposes hereinafter appearing, The larger diameter portion 61a of member 61 may to bias the members 60 and 63 in opposite axial direc tions and thereby bias the stop collar 72' toward engagement with the coupling member 63 as shown in Figures 1 m i and 3.

As shall become more apparent in the description of the operation of the device, the reset members 60 and 61 havefirst and second positions with respect to each other corresponding respectively tothe relative attracted W and retracted positions of the armature 52. The second relative position is assumed by said reset members in the off position of the control shown in Figure 1 wherein the portion 60b of member 60 projects from the member 61. The first relative position of the reset members is assumed when said members are depressed to afford the reset position of the control shown in'Figure 2 wherein reset members 60 and 61 and casing 13 are all flush, and in the cocked and energized or on position of the control shown in Figure 3 wherein the reset members 6t and 61 are flush with each other, and both are The member 63 is preferably formed with an annular rounded corner portion 630 forming a surface'for engaging a pivotally mounted switch lever'i'tl as best hown in Figure 3.; The open end of member 63 may be closed by a transversely disposed disc 63d which is rigidly be formed with a coaxial annular groove 61p extending outwardly from the inner end thereof. The groove 61p is adapted to receive a helical biasing spring 67 having one end abutting shoulder 13f and the other end bottoming in said groove to bias shoulder 61i into engage ment with shoulder 13c as shown in Figure 1, l The mid section of portion 61b is defined by a wall surface 61 and is adapted to slidably move within bore 13b with a reciprocatory movement to bemore fully explained. The axially outward surface 61 of the portion 61b is formed with a reduced diameter portion 61m to provide an annular cam shoulder 6111. The cam shoulder 6172 is adapted to move into and out of registry with transverse bore 13d for coaction with switch pin 15b of the igniter switch 15, so that when member 61 moves axially outwardly stop shoulder 611' moves into engagement with boss shoulder 13a (as shown in Figure 1), the cam shoulder 61n cams pin 15b outwardly (to the left in Figures 1 to 3), and Wall surface 61 thereafter maintains pin 15b in an outward or circuit-breaking position as long as the member 61 is in its outermost position. On the other hand, when the member 61 is moved toward the inwardly depressed position shown in Figure 2, wall portion 61 and shoulder 61h move out of registry with opening 13d, and pin 15b moves to the right as viewed in Figures 1 to 3 under the bias of spring 15a, to thereby close the switch 15 and energize the igniter circuit.

The inner reset member is formed with an enlarged head portion 60a which may if desired be painted a color contrasting with the color of the portion 61a of member V 61. Member 60 also has an elongated stem 60b which slidably fitswithin the axial bore 61d of the outer reset member 61. The enlarged head portion 60a is slightly smaller than bore 61c and is slidably movable therein. The stem 60b may have its inner endreduced at 600 to provide an annular shoulder 60a and extends downfixed thereto. 7

The coupling member has successively reduced outer diameter portions 63j and 63k forming annular shoulders 63n and 63m shown most clearly in the perspective view of Figure S. The side wall portion 63k of member 63 is formed with a generally U-shaped axiallyextending slot 63 and end member 63d is formed with a narrower radial U-shaped slot 63e in registry with slot 63 as shown in'Figure 5. Suitable locating means 63g may be provided to correctly locate member 63d with respect to member 63 so that slots 63e and 63 are aligned. Indicating means such as groove 63: may be formed on member 63 in axial alignment with slots 63e and 63 for ease in assembly.

As shown in Figures 1 to 3, the slot 63e is adapted to receive the grooved portion 55 of the armature stem 53, but is smaller in width than the diameter of end portion 53a of said stem. The slot 63 (Figure 5) is wide enough to permit entry therethrough of the stem end portion 53a. The coupling'member 63 thus provides quick detachable means for connecting the armature stem 53 to reset member 60. The indicating means 631 indicates the positionof slots 63c and 63f when the latter are hidden from view by the cup-shaped member '54 which telescopically fits over the portion 63k of member 63 p when the device is assembled, and engages shoulder 63m asshown in Figures 1 to 3. The axial length of surface 7 portion 63j is the distance between shoulder 63m and 63m I affords-a spacing between member 54' and shoulder 6311 sufficientto permit insertion of the fingernails of an operator, a screw driver or other suitable tool forpryingsaid members apart to afford access to the inner parts for assembly or disassembly of the reset and safety shut-off mechanisms. I

The operation of the improved apparatus is as follows:

Assume the following initial conditions, the various preventing position, disc valve 24 open, coupling member'63 engaging inner end surface 61k'ofmernber 60,

i.e. being in a first relativeposition with respect thereto,

Specifically, the condia so as to retain cam lever 70 in the outwardly swung switch actuating position shown to thereby maintain switch 14 open to maintain an open circuit to the main burner valve 31, switch pin 15b engaging the surface-ofportion 61 of the reset member 61 and held thereby in switch actuating position to maintain an open igniter circuit, and portions 61a and 60b of reset means 18 projecting outwardly beyond the plane of the casing 13 under the bias of springs 67 and 57, with portion 60b of reset member 60 projecting from the portion 61a of member 61 to thereby indicate the deenergized status of the safety shut-off means and the relative off positions of the parts.

To start the device in operation, the disc valve 24 in the pilot line is checked to make sure it is in flow-permitting position, so that fuel flow in the pilot supply line 27 is completely under the control of valve 22, when the latter is in the unlatched (normal) position shown in full line in Figure 1. When 100% shut-off is not desired, lever 75 is latched into the position shown in dashed lines by springing arm 90 upwardly and slipping lever 75 under detent 91. This removes valve 22 from control of the safety shut-01f means 48 and reset means 18 for applications where 100% shut otf is prohibited while retaining manual control and filtering of the pilot fuel supply. To reset the device and thereby initiate operation of the fluid fuel burning apparatus controlled thereby, indicating reset member 60 and outer reset member 61 are manually depressed to the position shown in Figure 2. The inward reciprocatory movement of the member 61 is transmitted to the armature stem 53 through the coupling member 63 to thereby move the armature 52 into engagement with magnet 49. During the first part of the reset movement, the inner reset member 60 is moved from the position shown in Figure 1, to a transitory flush position (not shown) with reset member 61. This movement is taken up entirely by compressing the spring 65 with no other parts moving. Upon the inner members 60 becoming flush with the outer reset member 61 said members move simultaneously.

No fuel may flow to the main burner during the reset movement as inward movement of the reset members 60 and 61 does not affect the open switch 14 in circuit to the main burner flow control valve 31 inasmuch as the switch lever 70 remains cammed toward its initial position by portion 6112 of member 61 during said movement. Thus switch 14 remains in circuit interrupting position during depression of the reset members 60 and 61.

Fuel to ignite the pilot burner is provided by the aforedescribed resetting movement, since the member 54 moves with the coupling member 63 to cause the cam surface 54b thereon to engage pilot valve lever arm 75, swinging the latter to the right as viewed in Figures 1 to 3, to thereby open valve 22 against bias of spring 28. Lever 75 is held in its flow-permitting position by the coupling member 63 as long as the armature 52 remains in attracted position with respect to the magnet 49 affording continuous pilot gas flow as long as said lever and the valve 22 are so actuated.

The igniter 9 is energized to ignite the pilot burner 11 by the inward reset movement of the member 61 allowing switch 15 to close. This occurs upon the removal of portion 61 of said member from engagement with the head of switch pin 15b, allowing the pin to move to the right to the position shown in Figure 2. Thus, the igniter circuit is energized from source 32 to provide ignition of the'fuel emanating from the pilot burner 11. Ignition of the fuel at the pilot burner 11 heats the thermoelectric generator 46 to cause the latter to generate a current which energized electromagnet coil 51. Energization of coil 51 is operable to retain the armature 52 in engagement with magnet 49 against the bias of spring 57.

Upon release of the reset means 18 the entire reset means will move from the position shown in Figure 2 outwardly to the position shown in Figure 3 under the bias of springs 67 and 65. Outer reset member 61 is thereby returned to its initial position, i.e. with shoulder 61: engaging shoulder 132. Inner reset member 60, however, may. move outwardly only the distance required to move stop collar 72 into engagement-with the inner surface of coupling member 63. When stop member 72 does so engage said inner surface under the bias of spring 65, the head 60a of inner reset member 60 is positioned substantially flush with member 61a as best shown in Figure 3 and said member 60 is held in this position by the'armature 52 acting through coupling member 63 and stems 53 and 60b. It is to be noted that the relative position'of members 60 and 61 shown in Figure 3, i.e., the projected flush position wherein the head 60a is unobtrusively retracted within the member 61a, affords means indicatingthat the parts are in on position.

Upward return movement of the reset means 18 also causes a separation of coupling member 63 and end surface 61k of reset member 61 to afiord a second relative position of said members as shown in Figure 3, since member 63 is attached to the armature stem 52 and is held thereby against following movement. This separating movement allows switch lever 70 to move in a clockwise direction under the bias of the spring 14a, closing switch 14 and thereby placing the circuit to the main burner flow control means under the exclusive control of the cycling thermostat 40.

The upward return movement of the reset means 18 also causes the igniter circuit to reopen by virtue of the cam action of shoulder 6111 on the member 61 reengaging and camming outwardly (to the left as viewed in Figures l to 3) the head of the igniter switch pin 15b.

It will be observed that the switch lever arm 70 is formed with a or bend 70a (Figures 2 and 3) which is preferably such that in the cocked energized on position of the parts shown in Figure 3, the lever 70 and the reset mechanism are interlocked so that the member 61, and hence the member 60 are held against further inward reciprocatory motion. Thus it is not possible to reclose the circuit to the igniter 9 or to reopen the circuit to the main burner valve 31 by depression of the reset means when the-magnet and armature are cocked and energized, since all downward motion is prevented until cam surface 630 moves lever 70 in a counterclockwise direction in response to pilot outage as will hereinafter appear.

It is also to be noted that the armature 52 will be reset to engagement with the magnet 49 by depression of either the inner reset member 60 or the outer reset member 61, singly, or as aforestated when they are depressed simultaneously. When the inner reset member 60 alone is depressed, motion is transmitted to the armature stem 53 through the abutting connection of the under side of the enlarged head portion 60a to member 61 at 2a, through coupling member 63 to the armature stem Upon pilot burner outage the generator 46 cools, and coil 51 on the magnet 49 deenergizes, releasing the armature 52 under the bias of spring 57, and causing outward movement of coupling member 63, i.e. upward movement thereof as viewed in Figures 1 to 3, thereby returning the parts to the initial position as shown in Figure 1. Outward movement of member 63 causes rounded cam portion 63c thereof to cam the lever arm 70 in a counterclockwise direction to thereby open the circuit to the main burner flow control means 31 and effect shut ofi of all fuel flow'to the main burner 12. Simultaneously, pilot fuel flow is shut ofi by the return of lever arm 75 to the position shown in Figure 1 affording closure of valve 22 under the bias of spring 28.

Although a specific embodiment of the invention has been shown and described it is with full awareness that many further modifications thereof are possible. The

invention therefore is not to be restricted except insofar as is necessitated by the prior, art and by the appended claims. 7,

a What is claimed bythe invention is 2 H p 1. In a control device, first and second resettablemernbers biased toward'separated relation and movable toward an engaged relation, a'reset member biased toward a releasedposition and 'actuatable to a reset position and operable to move said resettable members toward engaged relation by movement to reset position, and means having operative connection with at least one of said first and second members including a member mounted for movement to an obstructing position preventing actuation of said reset member from released toward reset position but only when said resettable members are in engaged relation, said connection effecting movement of said member to a non-obstructing position with movement of said resettable members toward separated relation.

2. In a control device,,first and second resettable members biased toward separated relation and movable toward an engaged relation, a reset member biased toward 'a released position and actuatable to a reset position and operable to move said resettable members toward engaged relation by movement to reset position, and control means having operative connection with at least one of said first and second members for movement of said control means from one to another controlling position by movement of said resettable members from engaged toward separated relation, the operative connection for said control means including a member mounted for movement to an obstructing position preventing actuation of said reset member from released toward reset position but only when said resettable members are in engaged relation, said operative connection effecting movement of said obstructing member to a non-obstructing position and movement of said control means to its other controlling position with movement of said resettable members toward separated relation.

3. In a control device, first and second resettable members biased toward separated relation and movable toward an engaged relation, a reset member biased toward a released position and actuatable to a reset position and operable to move said resettable members toward engaged relation by movement to reset position, control means having operative connection with said reset member and actuatable from one to another controlling position by actuation of said reset member, and means having operative connection with at least one of said first and second members including a member mounted for movement to an obstructing position preventing actuation of said reset member from released toward reset position and thereby preventing actuation of said control means but only when said resettable members are in engaged relation, said operative connection for said obstructing member efiecting movement of the latter to a non-obstructing position with movement of said resettable members toward separated relation.

4. In a control device, first and second resettable members biased toward separated relation and movable toward an engaged relation, a reset member biased toward a released position and actuatable to a reset position and operable to move said resettable members toward engaged relation by movement to reset position, first control means 'having operative connection with said reset member and f gas es meansibut only when said resettable members are in eri-j member tov a non-obstructing position and movement of c said second control means to its other controlling posia tion with' movement of said resettable members toward separated relation. t

5. In a control device, first and second members biased toward a separated relation and resettable to an engaged relation, reset means for resetting said members toward said engaged relation comprising first and second reset members each movable to a reset and biased toward a released position, one of said reset members being freely movable independent of said resettable members, and means affording a lost-motion connection between the other of saidreset members and at least one of said resettable members preventing return of said other reset member to its released position following a resetting operation so long as said resettable members are in engaged relation.

6. In a control device, a power unit comprising first and second magnetic members biased toward a separated relation and resettable to an engaged relation, a reset assembly for resetting said members toward said engaged relation comprising first and second reset members each movable to a reset and biased toward a released position, one of said reset members being freely movable independent of said resettable members, and means afiording a quick detachable lost-motion connection between the other of said reset members and one of said resettable members preventing return of said other reset member to its released position following a resetting operation so long as-said resettable members are in engaged relation, and permitting quick removal and replacement of either or both of said reset assembly and power unit.

7. In a control device, first and second members biased toward a separated relation and resettable to an engaged relation, reset means for resetting said members toward said engaged relation comprising first and second reset members each depressible to a reset and biased in the opposite direction toward a released position, one of said reset members being freely movable independent of said resettable members, means afiording a lost-motion connection between the other of said reset members and at least one of said resettable members preventing return of said other reset member to its released position following a resetting operation so long as said resettable members are in engaged relation, control means having operative connection with said one reset member eflzecting disposition of said control means in one controlling position or another in accordance with the position of said one reset member, means having operative connection with at least one of said resettable members including a member mounted for movement to an obstructing position preventing depression of said one reset member and actuation of relation, reset means for resetting said members toward said engaged relation comprising first and second reset members each depressable to a reset and biased in the opposite direction toward a released position, one of said reset members being freely movable independent of said resettable members, means affording a lost-motion connection between the other of said reset members and at I least one of said resettable members preventing return of said other reset member to its released position following a resetting operation so long as said resettable members I I are in engaged relation, control means having operative connection with said resettable members and movable from one controlling position to another by movement of 5:

said resettable members from engaged to separated relation, said operative connection including a member movable to an obstructing position preventing depression of said onereset member but only when said resettable members are in engaged relation, saidconnection effecting movement of said obstructing member to a nonobstructing position and saidicontrol means to its other controlling position with movement of 'said resettable member toward separated relation.

12 References Cited in the file of this patent UNITED STATES PATENTS 1,626,147 Moser Apr. 26, 1927 2,501,850 Kunzler Mar. 28, 1950 2,601,321 Ray June 24, 1952 FOREIGN PATENTS 1,033,659 France July 15, 1953