US3643583A

US3643583A - Blast valve actuator

Info

Publication number: US3643583A
Application number: US792263*A
Authority: US
Inventors: Norman George Fritz
Original assignee: International Harverster Corp
Current assignee: Solar Turbines Inc; Navistar Inc
Priority date: 1969-01-21
Filing date: 1969-01-21
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22

Abstract

Blast valve assemblies having a rotary or butterfly-type valve member and an actuator including a valve-closing mechanism which is cocked in an inoperative configuration when the valve is open. Pressure on the valve member or a signal to a solenoid incorporated in the actuator unlatches the valve-closing mechanism which slams the valve to its closed position. Reset mechanism is incorporated in the actuator to recock the closure mechanism and reopen the valve.

Description

United States Patent Fritz 5] Feb. 22,1972

[54] BLAST VALVE ACTUATOR 3,420,155 1/1969 Slater ..98/1 19 [72] Inventor: Norman George Fritz, Del Mar Calm 3,459,114 8/1969 Baclim 1 ..98/1 19 [73] Assignee: lntemational Harvester Company, San Primary Examiner-Meyer Perlin Diego, Callf- Attorney-Strauch, Nolan, Neale, Nies & Kurz [22] Filed: Jan. 21, 1969 [57] ABSTRACT [2 1] Appl. No.2 792,263

Blast valve assemblies having a rotary or butterfly-type valve member and an actuator including a valve-closing mechanism US. Cl which is cocked in an inoperative configuraion when the valve is open. Pressure on the valve member or a signal to a [58] Field of Search 1 37/463, 251/73, 98/119 Solenoid incorporated in the actuator matches tm valved, ing mechanism which slams the valve to its closed position. {561 References cued Reset mechanism is incorporated in the actuator to recock the UNITED STATES PATENTS closure mechanism and reopen the valve.

3,064,552 11/1962 Ehrsam ..98/l19 21 Claims, 19 Drawing Figures PAIENTEDFEBZZ I972 3.643.583

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SHEET 130F 13 INVE R NORMAN GEORG RITZ ATTORNEYS BLAST VALVE ACTUATOR The present invention relates to valves and, more specifically. to valves for protecting turbine intake and exhaust systems. building interiors, etc., from the overpressures caused by nuclear explosions and to novel improved actuators for such valves.

Generally speaking, the novel, improved blast valve assemblies described herein include a valve member of the butterfly type. a spring-driven actuator for closing the valve, mechanism for resetting the actuator and opening the valve member, and shock-absorbing mechanism for cushioning the impact as the valve member reaches its closed position to prevent damage to the components of the valve assembly and to minimize rebound of the valve member.

The major components of the novel actuator incorporated in the valve assembly just described include in addition to the spring which produces the valve-closing force and the reset mechanism an assembly for maintaining the spring in a compressed configuration, a trigger mechanism which is actuatable to displace the assembly just mentioned and release the spring to close the valve member, a latch mechanism which is operable to maintain the trigger mechanism in an inoperative configuration, and one or more actuators for freeing the trigger mechanism from the restraint exerted by the latch mechanism manually, automatically or upon the occurrence ofa condition dictating the closing of the valve member.

Important and primary objects of the invention are the provision of novel, improved actuators for blast valves of the rotary or butterfly type and the provision of blast valve assemblies having novel, improved actuators for closing the valve member of the assembly.

Other important but more specific objects of the present invention reside in the provision of novel, improved blast valve actuators which:

I. can be actuated to close a rotary-type blast valve either manually or automatically.

2. in conjunction with the preceding object, can be automatically actuated by the reaction of the valve member to blast wave overpressure.

3. in conjunction with objects Nos. 2 and 3, can be automatically actuated by the transmission of an electrical signal to the actuator.

4. are capable of closing a rotary-type blast valve in an extremely short period of time.

5. in conjunction with the preceding object. are capable of accomplishing the closing of the associated valve automatically once actuated.

6. in conjunction with the preceding objects 4 and 5, are capable of closing the associated valve rapidly without the imposition of damage causing shock on the valve or actuator components and without significant rebound of the valve member once it has reached the closed position.

7. can be reset with concomitant reopening of the associated blast valve from a remote location.

8. can be reset manually with concomitant reopening of the associated valve.

9. can be actuated to reclose the valve member during the portion of the cycle when the valve is being opened.

l0. cannot be spontaneously or inadvertently actuated.

l I. can be serviced without removal of the valve assembly.

Yet another important object of the present invention is the provision of novel blast valve assemblies which include valve actuators in accord with the preceding objects and various combinations thereof.

Other important objects and other novel features and advantages of the present invention will become apparent from the appended claims and as the ensuing detailed description and discussion proceeds in conjunction with the accompanying drawing, in which:

FIG. I is a front elevation ofa valve assembly constructed in accordance with and embodying the principles of the present invention;

FIG. 2 is a side elevation ofthe valve assembly of FIG. 1;

FIG. 3 is a side view of the actuator with its casing in part broken away to show its internal components;

hlbl

FIG. 4 is a section through the actuator, taken substantially along line 44 of FIG. 3;

FIG. 5 is a section through the actuator, taken substantially along line 5-5 of FIG. 3;

FIG. 6 is a section through the valve assembly. taken substantially along line 6-6 of FIG. 2;

FIG. 7 is a section through the valve assembly. taken substantially along line 7-7 of FIG. 2;

FIG. 8 is a section through the actuator, taken substantially along 8-8 of FIG. 4;

FIG. 9 is a plan view of a roller-lever assembly employed in the actuator;

FIG. 10 is a side view ofthe roller-lever assembly;

FIG. 11 is a transverse section through the roller-lever as sembly and certain components with which it cooperates;

FIG. 12 is a view of the actuator taken generally along line 12-12 of FIG. 3 with certain components removed to show other elements of the actuator;

FIG. 13 is a plan view ofa trigger incorporated in the actuator of FIG. 3; 7

FIG. 14 is a side view ofthe trigger;

FIG. 15 is a perspective view of the trigger;

FIG. 16 is a view ofthe actuator showing the positions of the roller-lever assembly and other components when the valve is closed and when it is being reset;

FIGS. 17 and 18 are partial, enlarged-scale sections through the roller-lever assembly and associated components. showing the roller-lever in and being released from its cocked position; and

FIG. 19 is a view similar to FIG. 8, but with different actuator components removed.

Referring now to the drawing, FIGS. 1 and 2 depict a blast valve assembly 40 constructed in accord with the principles of the present invention. The major components of the valve assembly are a valve member 42 rotatably supported in a valve body or duct 44 by trunnions 46, an actuator 48 for moving the valve member from its open to its closed position, a shock absorber 49 for cushioning the impact on the valve assembly components when valve member 42 reaches the closed position, and a reset mechanism 50 including an electric motor 51 drive-connected to actuator 48 through a ge'ar-r'eduction-type reset drive 52 for resetting the actuator and restoring the valve member to the open position after the actuator has been triggered to close the valve. In the'event of a power failure or other emergency conditions the actuator may alternatively be reset and the valve reopened by using crank 53 to. rotate the shaft 54 of motor 50. v

The details of the valve member and body as well as those of motor 50 and gear-reduction drive 52 are not part of the present invention. Accordingly, these components will not be particularized further herein except as is necessary to describe the novel features of the invention.

Turning next to FIGS. 3, 4, 8, l2, l6, and 19, on of the most important components of valve assembly 40 is the novel actuator 48 provided for pivoting valve member 42 from its open position to its closed position. It is critical in the applications in which valves of the type disclosed herein are employed that this closing movement be accomplished as rapidly as possible. Actuator 48 completely fulfills this requirement as it is capable ofclosing valve member 42 in periods having a duration on the order of as little as 0.05 second.

The major components of actuator 48, housed in a casing 56, include a spring motor 58 which provides the motive force for closing valve member 42 and is connected to the latter by a motion transmitting mechanism identified by reference character 60. With valve member 42 in its normal or open position the springs of spring motor 58 are maintained in the compressed configuration shown in FIG. 3 by a pivotable roller-lever assembly 62 and a slide assembly 64. Roller-lever assembly 62 is displaced to free spring motor 58 and thereby allow it to restore to its uncompressed configuration and close valve member 42 by a trigger 66 pivotably supported from slide assembly 64 and normally maintained in the inoperative position shown in FIGS. 3, 8, and 19 by a latch 68.

Trigger 66 is actuated to initiate displacement of rollerlever assembly 62 by energizing a solenoid 70 to disengage latch 68 from the trigger or by movement of valve member 42 under the influence of an overpressure which is transmitted to the trigger through motion transmitting mechanism 60 and a pivotably mounted, double-armed crank 72 which is located adjacent the trigger. The trigger may also be actuated manually by moving latch 68 out ofengagement with it.

Referring now specifically to FIGS. 3 and 16, the valve-closing spring motor 58 includes two concentrically arranged, outer and inner compression springs 74 and 76 of conventional construction housed in a casing 78 which is bolted or otherwise secured to main actuator casing 56. Outer spring 74 extends between casing end wall 80 and a fitting 84 fixed to one end of a shaft 86 which is the input member of motion transmitting mechanism 60. Inner spring 76 is similarly disposed between fitting 84 and end wall 80. Shims adjacent support 88 can be removed or increased in number to vary the force which spring motor 58 is capable of exerting when it is released.

At the upper end of motor 58 as shown in FIG. 3, springs 74 and 76 are maintainedin the proper position relative to each other and to casing member 82 by shims 90 and by a cylindrical guide 92 bolted to end plate 80. A similar function is performed at the opposite end of the motor by a cylindrical guide 94 fixed to fitting 84.

Referring next to FIGS. 4, 8, and 16, shaft 86 extends through slide assembly 64, which is slidable on the shaft and is butted against the shaft-carried fitting 84 when

springs

74 and 76 are compressed. Slide assembly 64 is accordingly driven downwardly as shown in FIG. 16 when roller-lever assembly 62 is displaced to the position shown in dotted lines in this Figure by actuation of trigger 66, freeing the springs for restoration to their uncompressed configuration to close valve member 42. Slide assembly 64 thus forms the second link in motion transmitting mechanism 60. In addition slide assembly 64 carries trigger 66 and the solenoid 70 and crank 72 which can be actuated to free the trigger from the restraint exerted by latch 68.

Referring now specifically to FIGS. 4, 8, and 16, slide assembly 64 has a longitudinal bore 98 through which shaft 86 extends. the relative dimensions of this bore and the shaft being such that the slide assembly is freely slidable on the shaft. Slide assembly 64 is restrained against rotation or twisting on shaft 86 by a longitudinal projection 100 which slides in a longitudinally extending groove or way 102 formed in wall member 104 of actuator casing or housing 56.

The next link in the motion-transmitting linkage 60 connecting spring motor 58 to valve member 42 is provided by a pair ofelongated members or links 106, which may be formed from conventional bar stock. At one end, links 106 are fixed to slide assembly 64 by pin 108, which extends through aligned openings 110 in slide assembly legs 112 and apertures 114 in link members 106. A sleeve bearing 115 surrounding pin 108 and extending through openings 110 and 114 and abutting slide assembly legs 112 provides freedom of rotation for link members 106. Pin 108 is secured in place by washer 116 and nut 118.

At their opposite ends link members 106 extend through slots 120 in transversely spaced, laterally extending arms 122 of a crank 124 (see FIGS. 3-5, 8, and 16), which is the next link of the motion-transmitting mechanism 60 connecting motor 58 to valve member 42. Link members 106 are pivotally fixed to crank arms 122 by pivot pins 126 which are retained in place by washers 128 and cotter keys 130.

As best shown in FIGS. 2 and 5, crank 124 is fixed to a transversely extending shaft 132 rotatably journaled in.

openings

134 and 136 in

actuator housing sidewalls

138 and 140 with

washers

142 and 144 interposed between the crank and the housing sidewalls to insure freedom of rotation (both of the two washers 144 may be placed on the same side of the crank to align the slots 120 in crank arms 122 with link members 106, if necessary).

At the right-hand end of shaft 132 as shown in FIG. 5, a gasket 146 and cover 148 are attached to casing sidewall 138 in any convenient fashion to keep dust from penetrating to the interior of the casing through opening 134.

The left-hand end of shaft 132 extends through the opening 136 in sidewall 140 and is rotatably connected to one of the two valve member supporting trunnions 46 by shaft 152. More specifically, the ends of shaft 152 are externally splined and extend into internally splined sockets 154 and 156 in shaft 132 and trunnion 46, rcspectively, thereby fixing the trunnion and blade member to shaft 132 for rotation therewith.

To elaborate on the closing movement of valve member 42 by the mechanism just described, the displacement of rollerlever assembly 62 by trigger 66 removes the restraint on

compressed springs

74 and 76 which accordingly expand, driving fitting 84, shaft 86, slide assembly 64, and link members 106 downwardly as shown in FIGS. 3, 8, and 16. This rotates crank 124, crankshaft 132, and splined shaft 152 clockwise as shown in FIGS. 3 and 16, thereby pivoting valve member 42 from the open position identified by reference character 158 in FIG. 16 to the closed position identified by reference character 160 (see FIG. 3). As indicated above, this all takes place in an extremely short period of time, which is typically not in excess of 0.05 second.

Because of the rapidity with which it is moved by spring motor 58, valve member 42 is capable of reaching its closed position with sufficient force to damage the valve member as well as the members of motion-transmitting mechanism 60 and other components of actuator 48. To absorb this shock and thereby prevent damage to the components just mentioned, the shock absorber 49 mentioned above is employed. Shock absorber 49, which may be of conventional hydraulic construction, includes a cylinder 164 bolted to casing wall member 104 and a piston or plunger 168 disposed in the path of valve member 42 as shown, in FIGS. 3 and 16. The operation of shock absorber 49 is conventional, its plunger 168 being driven into cylinder 164 to cushion the shock as the plunger is struck by the valve member.

To keep valve member from fluttering after it reaches the closed position, the hold closed mechanism 170 shown in FIGS. 2 and 6 is provided. This mechanism includes an elongated arm 172 bolted to a flange 174 on an intermediate cas ing 177 and a tension spring 178. As best shown in FIG. 6, one end of spring 178 is fixed to member 172 adjacent its outer or free end by a nut-and-

bolt arrangement

180, 181 and a spacer 182. The opposite end of spring 178 is connected via a link 184 to a plate 186 bolted to the outer end of the valve member supporting trunnion 46 nearer actuator 48.

As mentioned above, valve member 42 rotates in a clockwise direction as shown in FIGS. 1, 3, 6, and 16 in moving from the open position to the closed position. As will be apparent from FIG. 6, spring 178 exerts a clockwise force on valve member 42 through plate 186, which is removed from the axis of valve member rotation, and trunnion 46. In other words, spring 178 exerts a force in the closing direction to bias the valve member toward the closed position and prevent it from fluttering.

As best shown in FIG. 6, there are a series of apertures 188 in assembly member 172 through which bolt may be inserted. By inserting the bolt in different ones of these apertures, the tension on spring 178 and, accordingly, the force which the spring exerts on valve member 42 can be adjusted.

Referring still to FIG. 6, a pointer 190 is formed on the outer, free end of valve plate 186. This pointer cooperates with a position indicating plate 192 bolted to the side of flange 174 opposite member 172 to provide a visual indication of the position of valve member 42.

Turning now to FIGS. 2 and 7, an indication of the position of valve member 42 is also provided at a remote location by an arrangement including two

microswitches

194 and 196 disposed within and bolted to the intermediate casing 177 between valve casing 44 and actuator casing 56. As shown in FIG. 7,

microswitches

194 and 196 have plunger-type actuators 200 engageable by a lobe 202 on the splined shaft 152 drive-connecting crank shaft 132 of actuator 48 and valvemember-supporting trunnion 46. With valve member 42 in the open position, lobe 202 depresses the actuator and closes the contacts of microswitch 196. Similarly, with valve member 42 in the closed position, lobe 202 depresses the actuator and closes the contacts of microswitch 194. The contacts of the two microswitches are connected through leads identified generally by reference character 204 to a power source (not shown) and to indicator lamps (likewise not shown) which may be disposed at any desired location or locations. The appropriate lamp is lit by the closing of the associated microswitch when the valve member is respectively in the open position and the closed position.

Referring now to FIGS. 3, 812, and 16-18, the roller-lever assembly employed to retain

springs

74 and 76 in the compressed configuration shown in FIG. 3 includes a main casing or lever 206 pivotally fixed to vertically oriented bracket 208 by a pivot pin 210, which extends through arms 212 of the lever and bracket 208 and is secured in place by a nut 214 (see FIG. 12). Bracket 208 is in turn fixed to shaft'86 of motiontransmitting mechanism 60 by a bolt 216 and is maintained nonrotatable in actuator casing 56 by a horizontally projecting lug 218 disposed in an elongated guide or way 220 in actuator casing wall 222. Guide "220 is parallel to shaft 86 and thereby permits bracket 208 and roller-lever assembly 62 to move downwardly as shown in FIG. 16 with shaft 86 as valve member 42 is pivoted from its open to its closed position.

Lever 206 is normally maintained in the operative or springrestraining position by a spring 224 seated at one end in a spring seat 226 in bracket 208and seated at the opposite end in a seat 228 in lever 206.

Referring now specifically to FIGS. 8-12, in the configuration shown in FIG. 3, roller-lever assembly 62 maintains the

springs

74 and 76 of spring motor 58 in the compressed configuration by preventing downward movement of slide assembly 64 as shown in this Figure. More specifically, a pair of lateral, transversely extending,, spaced-apart projections 230 are formed on the slide assembly 64. Abutting projections 230 on the lower side thereofis a transversely extending roller 232 secured to slide assembly 64 as by capscrews 234. Engaging roller 232 when lever 206 is in the position shown in FIGS. 3 and 8 are three

rollers

236, 238, and 240 of the same diameter as roller 232, These three rollers also extend at right angles to shaft 86 and are so aligned with roller 232 that the longitudinal axes of all four rollers lie in a common plane 241 which is parallel to a plane including the longitudinal axis ofshaft 86.

Turning now to FIGS. 9-11,

rollers

236, 238, and 240 are carried by lever 206 and, more specifically, have reduced diameter end portions 242 which extend into vertical recesses 244 in cage plates 246 bolted to the free or left-hand end of lever 206. The lower ends of recesses 244 are closed so that

rollers

236 and 238 may move with respect to lever 206 but are retained in the lever along with roller 240 as the lever is displaced from the position shown in FIGS. 3 and 8.

As best shown in FIG. 8, an insert 247 is interposed between roller 240 and lever 206 and held in place by one or more pins 248. This insert transmits the thrust from roller 240 to lever 206 and, in addition, keeps

rollers

236, 238, and 240 in engagement with each other and with the roller 232 carried by slide assembly 64.

Referring now to FIGS. 17 and 1 8, the force exerted by

compressed springs

74 and 76 is transmitted through fitting 84 and slide assembly 64 to the roller 232 carried by the latter. With

rollers

236, 238, and 240 aligned with roller 232; i.e., with their longitudinal axes lying in plane 241, the force exerted by the springs is transferred from roller 232 through the

rollers

236, 238, and 240, lever 206, and bracket 208 to shaft 86. Shaft 86 is normally prevented from moving longitudinally by reset mechanism 50 as will become apparent hereinafter. Accordingly, as long as

movable rollers

236, 238, and 240 remain aligned, springs 74 and 76 are prevented from expanding; and valve member 42 remains in the open position.

Referring now particularly to FIGS. 8, 10, 17, and 18, the roller 240 is maintained in its aligned position by a depending projection 248a on lever 206, and movable rollers 236 and' tially seated in a recess 262 in lever arm 206 and provided with a projection 264 extending through an aperture 266 and provided plate 250. Interposed between rocker pin 260 and

movable rollers

236 and 238 and equidistantly spaced on opposite sides of the center of the pin are push rods 267 which extend through apertures 268 in the lever arm. Accordingly, spring 256, acting through rocker plate 250, rocker pin 260, and push rods 267 exerts a biasing force on

rollers

236 and 238, holding them against the free surface 270 of slide assembly 64, which is finished to very close tolerances so that the alignment of rollers 232,236,238, and 240 will be very accurate.

Referring now to FIGS. 8, l7, and 18, roller-lever assembly 62 is displaced to free the

springs

74 and 76 of spring motor 58 for valve-closing operation by moving roller 236 to the right against the force exerted by spring 256 and simultaneously moving roller 238 in the opposite direction. When this is done, the restraint exerted upon the slide assembly through roller 232 is removed, and spring motor 58, acting through fitting 84, forces slide assembly 64 downwardly as shown in FIGS. 3, 8, and 16. As it moves downwardly, the slide assembly pivots the roller-lever assembly to the right about pivot pin 210 to the position shown in dotted lines in FIG. 16; and valve member 42 closes as described above.

The movement of roller 236 just described is effected by actuation of the trigger 66 mentioned briefly above. More specifically, referring now particularly to FIGS. 3, 12-15, and 17-19, trigger 66 includes a transversely extending web 272 from which three parallel, spaced-

apart legs

274, 276, and 278 extend. Trigger 66 is pivotably fixed to slide assembly 64 by a pivot pin 280 which extends through transversely aligned apertures 282 in

trigger legs

274 and 278 and the two projections 230 of slide assembly 64 against which roller 232 is butted.

Pivot pin 280 is retained in place in any convenient fashion such as by the nut 284 and cotter key 286 shown in FIG. 12. Trigger 66 is'biased to the normal inoperative position shown in FIG. 19, for example, by a spring 288. As best shown in FIGS. 11 and 19, spring 288 is disposed between a spring seat 290 at the free end of trigger leg 278 and a spring retainer block 292 bolted to slide assembly 64. Spring 288 accordingly biases the forward portion of trigger 66 about pivot pin 280, thereby maintaining the trigger in the inoperative, normal position.

Trigger 66 is actuated for displacement of roller 236 by per mitting it to pivot about pivot pin 280 in a counterclockwise direction as shown in FIG. 19 under the influence of spring 288. As best shown in FIGS. 3 and 19, the trigger is normally restrained against this movement by latch assembly 68, which includes a horizontally extending arm 294 and a circularly sectioned detent 296 fixed to the right-hand end of the arm in any convenient fashion. Latch assembly arm 294 is pivotally fixed to a bracket 298 bolted to the lower end of solenoid mounting bracket 300 by a pivot pin 301. The arm is separated from bracket 298 by shims 302, which permit arm 294 to be adjusted so that detent 296 will seat in a correspondingly configured recess 304 in the forward end of trigger arm 274.

Trigger 66 can be freed for counterclockwise rotation to its roller-displacing position by pivoting latch assembly member 294 in a clockwise direction about pivot pin 301 as shown in FIG. 19, thereby displacing detent 296 from restraining engagement with trigger arm 274. This is accomplished by energizing solenoid 70 which has an actuator 306 fixed to the lefthand end of latch assembly member 294 and is supported from slide assembly 64 by the mounting bracket 300 just mentioned. Specifically, the solenoid is attached to bracket 300 as by a nut 308, which clamps the threaded rear end portion of the solenoid against a lateral extension 310 of the bracket.

Solenoid 70 is energized by completing a circuit through its coil (not shown) in any appropriate fashion. This may be done, for example, by closing a switch manually or by employing a pressure or other parameter responsive switch. Upon energization, the actuator 306 of the solenoid is retracted (i.e., moves upwardly as shown in FIG. 19). This pivots member- 294 in a clockwise direction as shown in the same figure,'freeing detent 296 from trigger arm 274. Thereupon the trigger pivots in a counterclockwise direction under the influence ofspring 288.

Referring now specifically to FIGS. 17 and 18, center trigger leg 276 has an upwardly directed extension 312 disposed in a longitudinal groove 314 in shaft 86 with the trigger leg aligned with movable roller 236 of roller-lever assembly 62 and engageable with the roller through an opening 316 in slide assembly 64. Accordingly, as trigger 66 pivots counterclockwise, middle leg extension 312 moves to the right, displacing roller 236 from the position shown in FIG. 17. As roller 236 moves to the right, it displaces the associated push rod 267 in the same direction, pivoting rocker pin 260 in a clockwise direction relative to rocker plate 250 as shown in FIG. 18. This in turn causes the rocker pin to push the rod 267 associated with roller 238 to the left displacing roller 238 in the opposite direction from roller 236. The net result is a displacement of roller 236 to the right out of plane of alignment 241 and a corresponding leftward displacement of roller 238. As discussed above, this removes the restraint exerted by the rollers on slide assembly 64 and thereby frees the

springs

74 and 76 of motor 58 for valve closing operation.

As indicated previously, the actuation of trigger 66 to initiate the valve-closing operation through displacement of roller 236 in the manner just described is also automatically accomplished by the arrival of a shock wave of sufficient intensity to produce an overpressure of, a predetermined minimum magnitude on valve member 42. Specifically, if the overpressure exerted on valve member 42 is high enough. it will displace the valve member past the closed position in which it is normally retained by the interaction between shock absorber 49 and actuator crack 124, causing trunnions 46, splined shaft 152, crankshaft 132, and crank 124 to rotate in a clockwise direction as shown in FIGS. 3 and 16, moving link members 106 downwardly as shown in the same Figures. Referring now specifically to FIGS. 12v and 19, link members 106 are fixed to lateral arms 320 of the lever or toggle 72 mentioned above by the same pin 108 operatively connecting the link members to slide assembly 64. As shown in the same figures, toggle 72 is pivotally supported from the slide assembly by the same pivot member 280 as trigger 66. Accordingly, the movement oflink members 106 pivots toggle 72 in a counterclockwise direction as shown in FIG. 19. As the toggle moves in'the counterclockwise direction, the lower end ofits arm 324 moves to the right, and a trip plate 326 bolted to arm 324 engages trigger arm 274 with sufficient force to move it out of engagement with detent 296. This frees the trigger for counterclockwise movement under the influence of spring 288. From this point the valve-closing operation of actuator 48 is as described above.

In conjunction with the foregoing, toggle 72 is normally maintained in an inoperative position with trip plate 326 separated from trigger arm 274 by a spring 328. This spring is disposed in a longitudinally extending aperture 330 in slide assembly 64 around a plunger 332 and is secured in place by a spring cap 334 fixed to the slide assembly in any convenient fashion (see FIGS. 3 and 8). Spring 328 biases pivot pin 108 upwardly as shown in FIG. 8, thereby biasing toggle 72 in a clockwise direction about pivot pin 280 to maintain trip plate 326 out of engagement with trigger 66. In the normal position the distance between the components just mentioned can be adjusted by varying the number of shims 335 between the trip plate and toggle arm 320.

As best shown in FIG. 8, the openings in slide assembly 64 through which pivot pin 108 extends are considerably larger in diameter that the pivot pin. This permits movement of the pivot pin relative to the slide assembly under the over pressure conditions described above to actuate trigger 66. This is necessary since, if the pivot pin and openings 110 were the same size, it would be impossible to pivot toggle 72 about pivot pin 280. Specifically, this would require movement of slide assembly 64 downwardly as shown in FIG. 8; and this is of course prevented by the restraining influence of roller-lever assembly 62. v

As mentioned above, trigger 66 may also be actuated I manually to initiatevalve-closing operation of actuator 48. This is accomplished by employing a suitable tool to displace trigger arm 274 out of engagement with detent 296 to free it for movement in'a counterclockwise direction by spring 288.

Provision is also made in valve assembly 40 for resetting actuator 48 and restoring valve member 42 to the open position after the valve mechanism had been closed. As mentioned above, this is accomplished by a reset mechanism 50 which includes an electric motor 51 having an output shaft 54 connected to a gear reduction drive 52 of conventional construction.

Referring now specifically to FIGS. 1 and 16, the output shafts 336 of the gear reduction drive is rotatably supported from reset mechanism housing 338 as by a bearing 340 and journals a pinion 342 which is fixed to shaft 336 for rotation therewith..Pinion 342 meshes with a gear 344 journaled on and rotatable about a threaded shaft 346 extending longitudinally through reset mechanism housing 338 in alignment with the shaft 86 of motion-transmitting mechanism 60. Threaded shaft 346 is fixed to shaft 86 by a square head 348 on the threaded shaft fitted into a correspondingly configured recess 350 in shaft 86 and a pin 352 which retains head 348 in recess 350. This arrangement fixes threaded shaft 346 against rotation since shaft 86 is prevented from rotating by the cooperation between the lug 218 on roller-lever assembly mounting bracket 208 and the elongated guide 220 in actuator housing wall member 222. I 7 Referring again to FIG. 1, gear 344 has an internally threaded hub portion 354 through which shaft 346 is threaded. Accordingly, as gear 344 is rotated, threaded shaft 346 is moved axially along a line coincidental with the longitudinal axis of shaft 86. v

To reset actuator mechanism 48 and reopen valve member 42, motor 51 is energized to rotate gear 344 through gearreduction drive 52 and pinion 342 in a direction effective to move threaded shaft 346 downwardly as shown in FIG. 1. As shaft 346 moves down, it pulls shaft 86 with it dueto the connection between the two shafts. Roller-lever assembly 62 also moves downwardly since the bracket 208 on which it is mounted is bolted to shaft 86.

Referring now to FIG. 3, as roller-lever assembly 62 moves downwardly, the lever is engaged by a roller 356 rotatably supported from actuator casing wall member 222 by axle 358 and bracket 360. As the downward movement continues, roller 356 pivots roller-lever assembly 62 in a counterclockwise direction as shown in FIG. 16 about pivot member 210 until roller 240 is again seated on the surface 270 of slide assembly 64.

At the same time that roller-lever assembly 62 is being pivoted by roller 356, the roller-lever assembly pivots trigger 66 in a clockwise direction about pivot member 280 due to the engagement between roller 356 and the projection 312 on trigger finger 276. Accordingly, as the roller-lever assembly reaches its normal, spring motor restraining position as best shown in FIG. 19, and is engaged and retained there by the reseating of detent 296 in the recess 304 at the end of trigger finger 274.

Following reset of the roller-lever assembly, trigger, and latch, the saddle or bracket 208 from which the roller-lever assembly is supported engages and depresses the actuator 362 of a switch 364 supported from actuator housing wall member 222 (see FIG. 3). Through a conventional circuit (not shown) this reverses the flow of current through the motor windings, causing its output shaft 54 to rotate in the opposite direction. This causes

shafts

346 and 86 to move upwardly as shown in FIGS. 3 and 16. As shaft 86 is pushed upward, it moves rollerlever assembly 62 in the same direction. Since the latter has at this point been reset, it in turn forces slide assembly 64 in the same direction. Due to the abutted relationship of the slide assembly and fitting 84, this displaces the lower ends of

springs

74 and 76 upwardly, recompressing them.

Referring now to FlGS. 3 and 16, as the

springs

74 and 76 of spring motor 58 reach their fully compressed configurations, a projection 366 on roller-lever mounting saddle 208 (see FIGS. 8 and 16) engages and depresses the actuator 368 of a second microswitch 370 (see F l6. 19) supported from actuator casing wall member 222. This opens the contacts of switch 370, interrupting the flow of current to motor 51 and completing the resetting cycle. Because of the longitudinal thrust exerted by the

springs

74 and 76 of spring motor 58, there is considerable friction between the cooperating external threads on shaft 346 and internal threads in hub 354 when motor 51 is deenergized. This friction prevents gear 344 from rotating and permitting shaft 86 to move in the valve-member-closing direction (ie. downwardly as shown in FIGS. 3 and 16, for example).

Asmentioned above, the reset cycle just described may also be accomplished manually in the event of a power failure or the like. This is accomplished simply by employing the crank 53 to rotate the output shaft of motor 54.

One of the important advantages of the novel resetting cycle just described is that the valve can be reclosed during the reset cycle, if necessary. Specifically, it will be apparent from the foregoing description of this cycle that the roller-lever assembly 62 and slide assembly 64 are in the same relative positions while

springs

74 and 76 are being compressed as they are whenthe valve is open and these components are in he positions shown in FIG. 16. Accordingly, should the minimum required overpressure be exerted on the valve member or trigger. 66 be actuated manually or by solenoid 70 after the latch has been reset and the upward movement of shaft 86 started, the valve member can be reclosed in the manner described above.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered .in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent 1. An actuator for a valve having a valve member movable between open and closed positions comprising resilient biasing means; a motion transmitting linkage having a rectilinearly movable input member operatively connected to said resilient biasing means and an output member adapted to be operatively connected to the valve member; retaining means for retaining said resilient biasing means in a compressed configuration, said last-mentioned means comprising a pivotally mounted lever, a plurality of relatively movable elements carried by said lever, one of said elements being engageable with abutment means on the input member of the motion-transmitting linkage, and means for normally maintaining said relatively movable elements aligned along an axis parallel to the direction of movement of said input member to restrain said member and the resilient biasing means against movement; and means for moving at least one of said movable elements out of alignment with the remainder of said elements to 10 remove the restraint upon the input member and resilient biasing means.

2. The actuator of claim 1, wherein said retaining means further includes means biasing said lever about its pivot axis toward a position in which the relatively movable elements are aligned along the axis parallel to the direction of movement of the input member of the motion-transmitting linkage.

3. The actuator of claim 1, together with means operable by the movement of one of said relatively movable elements in one direction generally at right angles to the direction of movement of the input member of the motion-transmitting mechanism out of its aligned position to displace another of said elements out of its aligned position in the opposite direction.

4. The combination of a pivotally mounted valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member which includes a member fixed for rotation with said valve member for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; shock-absorbing means engageable by said fixed member as valve member approaches its closed position to cushion the impact on the components of the valve actuator as the valve member reaches said closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration.

5. The combination of claim 4, together with means for indicating the position of the movable valve member.

6. The combination of a valve member movable between open and closed positions and an actuator for said valve member said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member which comprises first and second relatively movable members, one of said members being engageable with said resilient biasing means and the means for retaining the resilient biasing means in the compressed configuration being connected to the second of said members for movement therewith; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration, said lastmentioned means including means for moving the second member relative to the first member in a first direction; means for restoring said retaining means to the position in which it is capable of maintaining the resilient biasing means in a compressed configuration as said second member moves in said first direction; and means for thereafter moving said first and second members in a second direction to recompress said resilient biasing means.

7. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member, the motion-transmitting linkage comprising first and second relatively movable members, one of said members being engageable with said resilient biasing means, the second relatively movable member of the motion-transmitting linkage being threaded into a fixed actuator com- Anund Into means to restore to its uncompressed 'configurationand concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration, the means for resetting said retaining meansand recompressing said resilient biasing means comprising means for moving thesecond member relative to the first member in a first direction; means for restoring said retaining means to the position in which it is capable of maintaining the resilient biasing means in a compressed configuration as said second member moves in said first direction; and means for thereafter moving said first and second members in a second direction to recompress said resilient biasing means, the means for moving said first member comprising drive means for rotating said member.

8. The combination of claim 7, wherein said drive means comprises a motor drive connected to said first member.

9. The combination of claim 7, wherein said drive means comprises means for rotating said first member manually.

10. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member which comprises a rectilinearly movable input clement engageable by said resilient biasing means, an output member fixed relative to said valve member for rotation therewith, and an intermediate link pivotally fixed at one end relative to said input member and pivotally fixed at the opposite end to said output member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and

means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration. 7

II. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator-comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion transmitting linkage operatively connected between said resilient biasing means and said valve member which comprises first and second relatively movable'members, one of said members being engageable with said resilient biasing means and the means for retaining the resilient biasing means in the compressed configuration being connected to the second of said members for movement therewith; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage-so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration which comprises means for moving the second member relative to the first member in a first direction, means for restoring said retaining means to the position in which it is capable of maintaining the resilient biasing means in a compressed configuration as said second member moves in said first direction, and means for thereafter moving said first and second members in a second direction to recompress said resilient biasing means said last-mentioned means including an electric motor, a first switch means for reversing the direction of rotation of said motor when said first member has moved in the first direction a distance sufficient to effect reset of said retaining means and second switch means for deenergizing said motor when said first and second members have moved a distance sufficient to recompress the resilient biasing means to its compressed configuration.

12. The combination of a valve member movablebetween open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; pivotally mounted means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its openposition to its closed position. the means for displacing the retaining means comprising a trigger; means biasing said trigger toward a retaining means displacing position; a latch engageable with said trigger to retain it in an inoperative position against the restraint exerted by said biasing means; and means for freeing said trigger from the restraint exerted by said latch whereby said trigger will move toward said retaining means to effect a displacement of said retaining means and consequent closing of the valve member; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains saidbiasing means in said compressed configuration, which comprises a fixedly positioned cam and means for so moving said retaining means relative to said cam as to cause said cam to pivotally restore said retaining means to the position in which it is capable of retaining the resilient biasing means in the compressed configuration, said retaining means concomitantly engaging and restoring said trigger to its inoperative position for engagement and retention by said latch. 1

13. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connectedbetween said resilient biasing means and said valve member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motiontransmitting linkage so as to move the valve member from its open position to its closed position, the means for displacing the retaining means comprising a pivotally mounted trigger; means biasing said trigger toward a retaining means displacing position; a latch engageable with said trigger to retain it in an inoperative position against the restraint exerted by said biasing means; and means for freeing said trigger from the restraint exerted by said latch whereby said trigger will move toward said retaining means to effect a displacement of said retaining means and consequent closing of the valve member, said trigger having a first leg provided with means engageable by said latch to retain the trigger in the inoperative position; a second leg engageable with said retaining means to displace it from the position in which it retains said resilient biasing means in the compressed configuration; and a third leg, said biasing means being engaged with said third leg; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration.

14. The combination of claim 13, wherein said retaining means includes a plurality of relatively movable elements displacement of any one of which from a position in which it is aligned with the remainder of the elements will free said retaining means for displacement from the position in which said retaining means retains said resilient biasing means in the compressed configuration and wherein the displacement effecting means on said second leg comprises a projection en-

Claims

1. An actuator for a valve having a valve member movable between open and closed positions comprising resilient biasing means; a motion transmitting linkage having a rectilinearly movable input member operatively connected to said resilient biasing means and an output member adapted to be operatively connected to the valve member; retaining means for retaining said resilient biasing means in a compressed configuration, said last-mentioned means comprising a pivotally mounted lever, a plurality of relatively movable elements carried by said lever, one of said elements being engageable with abutment means on the input member of the motion-transmitting linkage, and means for normally maintaining said relatively movable elements aligned along an axis parallel to the direction of movement of said input member to restrain said member and the resilient biasing means against movement; and means for moving at least one of said movable elements out of alignment with the remainder of said elements to remove the restraint upon the input member and resilient biasing means.

6. The combination of a valve member movable between open and closed positions and an actuator for said valve member said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member which comprises first and second relatively movable members, one of said members being engageable with said resilient biasing means and the means for retaining the resilient biasing means in the compressed configuration being connected to the second of said members for movement therewith; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration, said last-mentioned means including means for moving the second member relative to the first member in a first direction; means for restoring said retaining means to the position in which it is capable of maintaining the resilient biasing means in a compressed configuration as said second member moves in said first direction; and means for thereafter moving said first and second members in a second direction to recompress said resilient biasing means.

7. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member, the motion-transmitting linkage comprising first and second relatively movable members, one of said members being engageable with said resilient biasing means, the second relatively movable member of the motion-transmitting linkage being threaded into a fixed actuator component, and the means for retaining the resilient biasing means in the compressed configuration being connected to the second of said members for movement therewith; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration, the means for resetting said retaining means and recompressing said resilient biasing means comprising means for moving the second member relative to the first member in a first direction; means for restoring said retaining means to the position in which it is capable of maintaining the resilient biasing means in a compressed configuration as said second member moves in said first direction; and means for thereafter moving said first and second members in a second direction to recompress said resilient biasing means, the means for moving said first member comprising drive means for rotating said member.

10. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member which comprises a rectilinearly movable input element engageable by said resilient biasing means, an output member fixed relative to said valve member for rotation therewith, and an intermediate link pivotally fixed at one end relative to said input member and pivotally fixed at the opposite end to said output member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration.

11. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion transmitting linkage operatively connected between said resilient biasing means and said valve member which comprises first and second relatively movable members, one of said members being engageable with said resilient biasing means and the means for retaining the resilient biasing means in the compressed configuration being connected to the second of said members for movement therewith; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration which comprises means for moving the second member relative to the first member in a first direction, means for restoring said retaining means to the position in which it is capable of maintaining the resilient biasing means in a compressed configuration as said second member moves in said first direction, and means for thereafter moving said first and second members in a second direction to recompress said resilient biasing means, said last-mentioned means including an electric motor, a first switch means for reversing the direction of rotation of said motor when said first member has moved in the first direction a distance sufficient to effect reset of said retaining means and second switch means for deenergizing said motor when said first and second members have moved a distance sufficient to recompress the resilient biasing means to its compressed configuration.

12. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; pivotally mounted means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position, the means for displacing the retaining means comprising a trigger; means biasing said trigger toward a Retaining means displacing position; a latch engageable with said trigger to retain it in an inoperative position against the restraint exerted by said biasing means; and means for freeing said trigger from the restraint exerted by said latch whereby said trigger will move toward said retaining means to effect a displacement of said retaining means and consequent closing of the valve member; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration, which comprises a fixedly positioned cam and means for so moving said retaining means relative to said cam as to cause said cam to pivotally restore said retaining means to the position in which it is capable of retaining the resilient biasing means in the compressed configuration, said retaining means concomitantly engaging and restoring said trigger to its inoperative position for engagement and retention by said latch.

13. The combination of a valve member movable between open and closed positions and an actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position, the means for displacing the retaining means comprising a pivotally mounted trigger; means biasing said trigger toward a retaining means displacing position; a latch engageable with said trigger to retain it in an inoperative position against the restraint exerted by said biasing means; and means for freeing said trigger from the restraint exerted by said latch whereby said trigger will move toward said retaining means to effect a displacement of said retaining means and consequent closing of the valve member, said trigger having a first leg provided with means engageable by said latch to retain the trigger in the inoperative position; a second leg engageable with said retaining means to displace it from the position in which it retains said resilient biasing means in the compressed configuration; and a third leg, said biasing means being engaged with said third leg; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration.

14. The combination of claim 13, wherein said retaining means includes a plurality of relatively movable elements displacement of any one of which from a position in which it is aligned with the remainder of the elements will free said retaining means for displacement from the position in which said retaining means retains said resilient biasing means in the compressed configuration and wherein the displacement effecting means on said second leg comprises a projection engageable with one of said relatively movable elements to displace said element upon pivotal movement of said trigger under the influence of the biasing means associated therewith.

15. The combination of claim 13, wherein the latch engageable means of said first trigger leg comprises a recess in the end thereof opposite that at which the trigger is pivoted and wherein said latch comprises a pivotally mounted member adjacent said recessed end of said first trigger leg and a detent carried by said latch and located opposite said recess, and means for pivoting said latch about its pivot axis to seat said detent in the recess in the trigger leg.

16. The combination of a valve member movable between open and closed positions and an actuator for said valve member said actuator comprising resilient biasing means; means for retaining saId resilient biasing means in a compressed configuration; a motion-transmitting linkage operatively connected between said resilient biasing means and said valve member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position, the means for displacing the retaining means comprising a trigger; means biasing said trigger toward a retaining means displacing position; a latch engageable with said trigger to retain it in an inoperative position against the restraint exerted by said biasing means; and means for freeing said trigger from the restraint exerted by said latch, whereby said trigger will move toward said retaining means to effect a displacement of said retaining means and consequent closing of the valve member, said last-mentioned means comprising a pivotally mounted double-armed crank having one arm engageable with said trigger to free it from the restraint exerted by said latch and means so operatively connecting said motion-transmitting linkage to the other arm of said crank that movement of the valve member toward its closed position exceeding a minimum magnitude will through said linkage move said one arm of said crank a distance sufficient to free said trigger from the restraint exerted by said latch; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration.

17. The combination of a valve member movable between open and closed positions and a actuator for said valve member, said actuator comprising resilient biasing means; means for retaining said resilient biasing means in a compressed configuration; a motion-transmitting mechanism operatively connected between said resilient biasing means and said valve member which comprises an input member engageable by said resilient biasing means, an output member operably connected to said valve member, an intermediate link disposed between said input and output members, first means operably connecting said intermediate link to said output member, and second means so connecting said intermediate link to said input member as to permit limited relative movement therebetween, whereby overpressure-generated movement of said valve member will effect movement of said intermediate link irrespective of the absence of movement of said input member; means for displacing said retaining means to permit said resilient biasing means to restore to its uncompressed configuration and concomitantly actuate said motion-transmitting linkage so as to move the valve member from its open position to its closed position, the means for displacing the retaining means comprising a trigger; means biasing said trigger toward a retaining means displacing position; a latch engageable with said trigger to retain it in an inoperative position against the restraint exerted by said biasing means; and means for freeing said trigger from the restraint exerted by said latch whereby said trigger will move toward said retaining means to effect a displacement of said retaining means and consequent closing of the valve member, the means for freeing the trigger from the restraint exerted by the latch comprising a pivotally mounted double-armed crank having one arm engageable with said trigger to free it from the restraint exerted by said latch and means so operatively connecting said motion-transmitting linkage to the other arm of said crank that movement of the valve member toward its closed position exceeding a minimum magnitude will through said linkage move said one arm of said crank a distance sufficient to free said trigger from the restraint exerted by said latch, the means operatively connecting the pivotally mounted crank to the motion-transmitting mechanism comprising means pivotally connecting said other arm of said crAnk to said intermediate link; and means for thereafter recompressing said resilient biasing means and resetting said retaining means to the configuration in which it maintains said biasing means in said compressed configuration.

18. The combination of claim 17, together with means operatively disposed between said input member and said intermediate link and biasing said link in a direction in which said link tends to maintain said valve member in a fully open position and to maintain said one arm of said double-armed crank out of engagement with said trigger.

19. An actuator for a valve having a valve member movable between open and closed positions comprising resilient biasing means; a motion-transmitting linkage having a rectilinearly movable input member operatively connected to said resilient biasing means and an output member adapted to be operatively connected to the valve member; retaining means for retaining said resilient biasing means in a compressed configuration, said last-mentioned means comprising a pivotally mounted lever, a plurality of relatively movable elements carried by said lever, said relatively movable elements being rollers oriented with their longitudinal axes at right angles relative to the direction of movement of the input member of the motion-transmitting mechanism with the end portions of said rollers disposed in cooperating grooves in said lever so configured as to permit relative movement between the rollers and the lever and one of said elements being engageable with abutment means on the input member of the motion-transmitting linkage, and means for normally maintaining said relatively movable elements aligned along an axis parallel to the direction of movement of said input member to restrain said member and the resilient biasing means against movement; and means for moving at least one of said movable elements out of alignment with the remainder of said elements to remove the restraint upon the input member and resilient biasing means.

20. The actuator of claim 19, wherein the abutment means on the input member of the motion transmitting mechanism comprises a shoulder on said member and a cylindrical member fixed to said input member in juxtaposition to said shoulder, the longitudinal axis of said cylindrical member lying in the same plane as the axes of the relatively movable rollers with the retaining means in the position in which it retains the resilient biasing means in the compressed configuration.

21. An actuator for a valve having a valve member movable between open and closed positions comprising resilient biasing means; a motion-transmitting linkage having a rectilinearly movable input member operatively connected to said resilient biasing means and an output member adapted to be operatively connected to the valve member; retaining means for retaining said resilient biasing means in a compressed configuration, said last-mentioned means comprising a pivotally mounted lever, a plurality of relatively movable elements carried by said lever, one of said elements being engageable with abutment means on the input member of the motion-transmitting linkage, and means for normally maintaining said relatively movable elements aligned along an axis parallel to the direction of movement of said input member to restrain said member and the resilient biasing means against movement; means for moving at least one of said movable elements out of alignment with the remainder of said elements to remove the restraint upon the input member and resilient biasing means; and means operable by the movement of one of said relatively movable elements in one direction generally at right angles to the direction of movement of the input member of the motion-transmitting mechanism out of its aligned position to displace another of said elements out of its aligned position in the opposite direction, said last-mentioned means comprising a member mounted for rocking movement along an axis parallel to the direction of movement of the input memBer of the motion-transmitting mechanism, first and second members disposed between said rockable member and different ones of said relatively movable elements, said first and second members being on opposite sides of the axis about which said rockable member rocks, and means biasing said rockable member into engagement with said first and second members and said first and second members into engagement with the associated relatively movable elements, whereby movement of one of the elements associated with said first and second members in said one direction out of its aligned position will effect movement of the other of the relatively movable elements associated with said first and second members out of its aligned position in said opposite direction.