US3775710A

US3775710A - Pneumatic timer attachment for an electromagnetic relay

Info

Publication number: US3775710A
Application number: US00276273A
Authority: US
Inventors: D Cook
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1971-08-06
Filing date: 1972-07-28
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27
Also published as: IT964888B; GB1407674A; CA977399A

Abstract

A timing chamber is defined by a flexible diaphragm having an exhaust port controlled by a valve. During the time period, air enters the timing chamber at a rate determined by relatively rotatable and facing timing discs defining a capillary path of variable length therebetween. The rate of entry of air into the timing chamber determines the time period by controlling the rate of return of the diaphragm to a normal position and a corresponding movement of a contact carrier to a normal position. The contact carrier has an offset foot portion which is engaged by a rocker driven by the armature of the relay to reset the timer. By mounting the timing attachment selectively in two different turned positions on a relay, time delay after energization or after de-energization of the relay is provided.

Description

I United States Patent 1 1 1 1 3,775,710 Cook 1451 Nov.- 27, 1973 PNEUMATIC TIMER ATTACHMENT FOR AN ELECTROMAGNETIC RELAY Primary Examiner-Harold Broome [75] Inventor: David Langman Cook, Swindon, AttorneyfiHarold Rathbun et England [73] Assignee: Sqnare D Company, Park Ridge, 11]. [57] ABSTRACT A timing chamber is defined by a flexible diaphragm [22] Flled' July 1972 having an exhaust port controlled by a valve. During [21] Appl. No.: 276,273 the time period, air enters the timing chamber at a rate determined by relatively rotatable and facing timing discs defining a capillary path of variable length [30] Foreign Application Priority Data therebetween. The rate of entry of air into the timing Aug. 6, 1971 Great Brltain 3,677/71 chamber determines the time period by controlling the rate of return of the diaphragm to a normal position [52] US. Cl. 335/61 and a corresponding movement of a Contact carrier to [51] Ill!- Cl. H01]! 7/03 a normal position-L The Contact carrier has an offset [58] Fleld of Search 335/61, 59, 62 foo portion which is engaged by a rocker driven by J i the armature of the relay to reset the timer. By mount- [56] References cued ing the timing attachment selectively in two different UNITED STATES PATENTS turned positions on a relay, time delay after energiza- 3,509,501 4/1970 Brovedan 335/61 tion or after de-ehergization 0f the relay is Provided 3,599,131 8/1971 Flanagan 335 61 2,538,038 1 1951 Ponstingl et al. 335/6] 13 Clam, 14 Drawmg Flg'lles PATENTEDN HBB I 3,775,710

I SHEET 2 (IF 5 tacts, or selectively, an adjustable time delay between I the return of. the manual .operator or the d'eenergization of the operating coilandthe operation of the contacts. c

Prior timers of this type have been characterized by a relatively complex diaphragm and associated valve mechanism which are expensive to manufacture and require considerable space, and by'an inability to be readily converted from time delay after energization to time delay after de-energization and vice versa. In addition, variations in manufacture of component parts time periods providedby individual timersfrom different or even the same production runs. Furthermore, some prior art timers have employed mechanisms in which the relationship between the timedelay actually provided and the setting of :the timing adjustment means has been extremely'non-linear.

Accordingly, it is an object of .the present invention to provide an improved adjustabletimedelay apparatus or timer which is relatively inexpensive tomanufacture, which may be calibrated simply and accurately following initial assembly thereof, which maybeeasily and quickly installed, and in which the relationship between the delay time period and the setting of the timing adjus ment means is substantially linear.

Another object is to provide such an improved adjustable timing device which may have a time delay range adjustable from 0.2 to 30 seconds with a single turn of an adjusting knob, and which maybe readily converted to provide time delay after energization (TDE) or time delay after de energization (TDD) of its operator. 4

A A further object isto provide such an adjustable timing device which. has a-substantially constant resetting time for successive timing operations.

The time delay apparatus of this invention is-particularly well suited for use as'a timing attachment for an electromagnetic relay and the inventionwill be de scribed principally as embodied in such a timing attachment although it will become apparent that the invention has other applications l Other objects, features, and advantages of the present invention will become aPParentfromthe following description of particular embodimentstaken together with the attached drawings thereof, in which:

FIG. 1 is a partially exploded perspective view showing a pneumatic timer attachment constructed in accordance with' this invention in its housing, a rocker :and carrier insertassembly employed with the timer attachment, a relay contact "carrier, two relay contact blocks, and one of two retaining springs;

FIG. 2 is a view in side elevation and partially broken away of the upper portion of the timer attachment of vFIG. l;

FIG. 3 is a view in cross section, taken along line 3-3 in FIG. 1, of the timer attachment;

. have resulted in undesirable differencesbetween the FIG. 4. is a view in cross section, taken. along line 4-4 of FIG. 3, showing a lower timingdisc of the timer attachment of FIG. 1 in solid lines and an upper timing disc in phantom lines; v

FIG. 5 is a plan view of the upper underside of the timing disc of the timer attachment v FIG. 6 is an ex ploded perspective view of therocker and carrier insertassembly employed-with the timer attachment;

FIG. 7 is a partially assembled perspective view of the rocker and carrier insert assembly with an extension of a hook arm portion of the carrier insert in an unclasped position; i

FIG. 8 is a view, partially in cross section, showing a portion of the lower housing and contact carrier of the timer attachment, positioned for time delay after energization, and of the rocker, carrierinsert and an associated relay after de-energization of the relay;

FIG. 9 is a view, partially in cross section, showing a portion of the lower, housing and contact carrier of the timer attachment, positioned for time delay after energization, and of the rocker, the carrier insert and the relay contact carrier after energization of the relay;

FIG. 10 is a view, partially in cross section, showing a portion of the lower housing and contact carrier of the timer attachment, positioned for time delay after de-energization, and of the rocker, the carrier insert and the relay relay;

FIG. 11 is a view, partially in side elevation, partiallyv timer attachment at the start of a timing stroke;

FIG. 13 is a pneumatic schematic diagram of the timer attachment at the start'of a resetting stroke;and

FIG. 14 is a plan view of the front of the timer attachment showing an adjusting knob, visible indicia on the adjusting knob, and the front cover of the timing attachment- Referringnow to FIG. 1 there is shown a'pneumatic time attachment, generally designated 10, and its-associated rocker and carrier insert assembly, generally designated 12, including a rocker'14 and a carrierfinsert l6both of which will be discussed in greater detail below.

The timer attachment 10 includes a molded plastic front or upper stepped cover 18, a molded plastic front or upper housing 22, and, integral with and extending rearwardly of a rear or lower. molded plastic housing 23, a pair of

mounting lugs

24 and 26 each having a stepped clamping surface 28 (only one surface .28

shown in FIG. 1). A time delay adjustment knob .30, which'is rotatable to provide a delay over a range of from 0.2 to 30 seconds, is secured'at the face of the cover 18 by a screw 32, and terminal portions of lower stationary contact straps 33-34, extend outwardly through slots formed in one side of the rear housing 23 at the line of junction with the front housing 22. Simi- .larly, terminal portions of upper contact straps 35-36 (FIG. 4) extendoutwardly through slots formed in the contact carrier after energization of the 3 43 are provided in the rear edges of opposite sides of the rear housing 23.

Also shown in FIG. 1 are a left-hand contact block 44, a right-hand contact block46, and a relay contact carrier 48 having at thefront or upper end portion thereof a pair of rearwardly extending spaced recesses 50 each having. a recess 52 extending laterally outwardly at therear thereof. Each of the

contact blocks

44 and 46 has a pair of stepped

opposite end surfaces

54 and 56 respectively (only one stepped end surface shown for each), providing pairs of

recesses

58 and 60, respectively, and pairs of

clamping surfaces

62 and 64, respectively. As is well known to those skilled in the art to which the invention pertains, when the relay is assembled, the contact blocks44 and 46 are mounted on a relaybase 65 (FIG. 8) on opposite sides of the relay contact carrier 48 and the

stepped end surfaces

54 and 56 on the

contact blocks

44 and 46, respectively, cooper'ate to define at each endof the contact blocks a single'recess 58, and'a single clamping surface 62, 6.4 about which retaining clips 66,only one of which is shown in FIG. 1, rotatably secured at the lower portion of the relay base may be passed to firmly hold the

contact blocks

44 and 46, in place on the relay base 65 in cooperative relation with the relay contact carrier 48.

The timer attachment 10 may be simply and quickly installed in place on a relay without removing the relay from a panel on which it is mounted by releasing the retaining clips 66 and removing a non-functional insert (not shown) which is inserted into recesses 50 in the relay contact carrier 48 during initial assembly of the relay. The timer attachment carrier insert 16- with the rocker 14 attached thereto may then be inserted in place in the recesses 50, the contact blocks 44 and 46 a reassembled in place around the relay contact carrier 48, and the timer attachment 10 installed by positioning the

mounting lugs

24 and 26 of the rear housing 23 in the recesses 58-60 at each end of

contact blocks

44 and 46 and then rotating the retaining clips 66 (FIGS. 1 and 8) into place against

clamping surfaces

28 and 62, 64.

Referring now to FIGS. 2 and "3, wherein the pneu- 'matic timer attachment 10 is shown in greater detail, a

metallic front member 68 is provided and has a central opening, including a threaded screw receiving passage 70 and a cylindrical spring seat receiving passage 72 of increased diameter, which communicates with the passage 70, the passages 70 and 72 extending through a front'neck portion 74 and a rear body portion 76 of the member 68. The rear body portion 76 includes eight spokes 78 (two are shown in FIG. 3) which extend at equal angles radially outwardly from a central or core portion about the openings 70-72, a generally rectangular rear flange 80 having an annular rib 82 extending rearwardly therefrom, and a stepped cylindrical passage 84 extending through a thickened portion of one of the spokes 78a of the rear body portion 76.

The front housing 22, the rear housing 23, and the front member 68 are arranged to be secured together by four screws (not shown) which pass upwardly as viewed in FIG. 3 through :four holes in the corners of each of the rear'housing 23, and thefront housing 22 and thread into four holes tapped respectively in rearwardly extending bosses of the'flange 80 of the front member 68.

4 The front housing 22 and the rear housing 23 are provided with complementary recesses and projections and, when assembled-together with the front member 68, cooperate with each other and with the'front member 58 to define a lower contact cavity 86, and a main cavity 88. An annular'rigid element 92 and a flexible diaph gm 94' ';d ifvid e the main cavity 88 into first and secon chambers-'96 and 98. The'first chamber 96 is the chamber to" be evacuated while the second chamber 98 is the discharge chamber) 8 v l The flexible diaphragm 94hasa central orifice 100 and is bifurcated radiallyl outwardlyfrom the orifice 100 to definean annular recess102 into which a pe-. I

ripheral portion of the rigid element 92 is seated. A valve seating surface 104 surrounds the orifice 100. The diaphragm 94 also has an increased thickness portion 106 received in an annular groove formed between the rib 82 'on the flange-80 of the front member 68 and a ledge near the top of the upper housing 22. A valve spindle having an upper closure disc portion 108 dis- "posed above .the .valve seating, surface 104 and a stepped cylindrical shaft portion 109 projecting downwardly from the disc portion 108 extends through the orifice 100, through an opening in the rigid element 92, and through an opening in an annular spring seat 110 disposed within a space defined by an annular rib 111 extending forwardly on a rear wall or base 112 of the front housing 22.

An adjusting screw 113 for the spring 122 is provided and has a threaded front or upper cylindrical neck portion-114, which has a slot 116 formed in the top surface thereof and is arranged to be screwed into the screw receiving passage 70, and, disposed within the passage 72, a rear or lower increased diameter spring seat portion 118 having a spring seating surface 120. A compression spring 122 disposed between the spring seating surface and the valvedisc portion.108 and is arranged to force the disc portion 108 normally into' I engagement-with the .valve seating surface 104. The spring seatportion 118 has an annular groove formed in the outer periphery thereof and an O-ring 126- is 'seated in the groove and is arranged tofform an effective seal between the spring seat portion 118 and the walls of the passage 72. I

A compression control spring 128 is seated'between the annular rigid element 92 and the spring seat 110 and is arranged to control flexure of the diaphragm 94 when the spring seat 110- is moved forwardly.

The valve spindle shaft portion 109 has a lower splined end portion securely received in a generally tu-.

bular recess 130 in a front or upper neck portion 131 of a timing attachment contact carrier 132 of a snap switch. The neck portion 131 is received in an opening in the base 112 of the front housing 22. The contact cavity 86 formed between the upper housing 22 and the lower housing 23 contains the snap switch which. is constituted by lower

stationary contacts

133 and 134 on the strps'3'3'a'nd 34, respectively, upper

stationary contacts

135 and 136 on

thestraps

35 and 36, respectively,

and a pair of double-faced movable contacts 138 carried by a contact bridge 140slidably inserted about a portion of the carrier 132. A fulcrum 142, formed by two opposing wedged-shaped indentations 144, is contained in the portion-of the carrier l32 'surrounded by g the bridge 140.

. Respective inner end portions of two

fiat springs

148 and 150 are inserted in the indentations 144, respectively. The outer ends of the springs 148-150 are connected to the bridge 140 as by reception in suitable openings in the bridge so that the bridge 140 is caused to detach from the fulcrum 142. Thus, the carrier 132 when displaced is arranged to shift the'fulcrum 142 to tail below) mounted on the relay contact carrier 48.

Theupper or front cover 18 of the timer attachment 156. An annular porous polyurethanefilter 158 (having 80 pores per linear inch) and an associated annular perforatedmetallic plate, defining a filter support 160, are supported on the flange 80 of the front member 68 within the stepped "sidewall 155. Suitable tublar passages 162 (FIG. 14) circumferentially disposed about and intersecting the outer edge of an annular recess 163 in the upper surface of the flange 80 define fluid paths in conjunction with radialslots 163a in the upper face of the housing 22. The recess 163 may have a labyrinth 16311 of concentric and radial chambers for better distribution of air into the filter 158.

The front cover 18 is further provided with a passageway 164, aligned withthe passage 84 through the spoke 78d of the body portion 76 of the member 68. An annular seal 166 having an opening therethrough aligned with the passage 84 and the passageway 164 is seated between the upper surface of the spokes 78 and the top of the front cover- 18. Two like superimposed

annular seals

170 and 172 are disposed within the area defined by the rib 156, and a lower timing disc 174 (to be discussed in greater detail below) is mounted on the seal 172. Each of the 'seals 170 and 172 and the lower timing disc 174 has an opening, generally designated 176,

either side of the bridge 140 which in turn is compelled ,rier insert assembly 12(to be describedin greater de'- has a stepped sidewall 155. and .anannular front rib therethrough andaligned with .the passageway 164- through the passageway 164 and the openings 176, and terminates withinthe aligned opening in the lower timing disc 174. The roll pin 178 prevents rotation of the lower timing disc 174 and the

seals

166, 170 and 172 with respect to the from member 68 and the front cover 18.

The adjusting knob 30 is provided with a central opening arranged to accommodate the upper or front neck portion 74 of front member 68', a front recess 180, and an annular rear recess 184. An annular clamping disc 186 and awave washer 188 are arranged to be seated in the recess 180 around the front portion 74 and an annular seal 190 and an upper timing disc 192 (to be discussed in greater detail below) are arranged to be seated in the recess 184, the upper disc 192 being in face-to-face engagement with the lower disc 174.

FIGS. 6 and 7 show the rockedr l4 and carrier insert 16 associated with the invention in greater detaiLThe carrier insert 16 has an upper body portion 194 and two downwardly projecting

leg portions

196 and 198 having

feet portions

200 and 202, respectively, which project outwardly from

leg portions

196 and 198, respectively, in opposite directions. The leg portions 196 against rotation to detents in the recess 184 of the adjusting knob 30, and has a radially extending oblong rethrough the front cover 18. A hollow tubular roll pin 178 is force fitted in passage 84, extends upwardly" and 198 and their corresponding feet potions 200'and 202 are shaped and spaced to permit them to be inserted in the recesses 50 inthe relay contact carrier 48 (FIG. 1) and to have the feet portions 200-and 202 engaged in place in the outwardextensions 52 of the recesses 50. A hook "arm portion 204 extends from the upper body portion 1940f the carrier insert 16 and a flexible extension '206 of hook arm portion 204 extends therefrom adjacent a recess 208 in the hook arm portion 204. The extension 206 includes a thin flexible connecting section 210 and an engagement section 212 which has a concave face 214 and terminates in an end surface 216 which is arranged to be held in a recess 218 of the upper body portion 194 when the connecting .1

section 210 and the engagement section 212 are rotated from the position shown in FIG. 6 around a web .220 of the rocker 14 (FIG. 7) after the web 220 has beenjnserted' in place in the recess 208 under the hook arm portion 204. Aboss 221 on the web 220 enters an opening 222 in the hook arm portion 204.

The rocker 14 also includes a web 223 at the opposite end from the web 220, the webs forming part of a rocker bodyportion having spaced side members 224,

and includes a pair of aligned shafts 226 projecting in opposite directions from the respective side members 224 and having enlarged

cylindrical bearing portions

227 and 228 and outer spindle portions 230, respectively, arranged to be seated in the respective rocker spindle bearing recesses 43 in the rear or lower edge of rear or lower housing 23 of the timer attachment. The boss 221 has a camming or engagement surface 234 facing upwardly therefrom. Each of the spindle portions 230 has a groove 236 extending across the outer end thereof which is exposed outside the housing when the timer attachment is inserted in place in the rocker spindle bearings'43 to facilitate manual operation of the timing device by a screwdriver for testing purposes without energizing the associated relay.

The lower timing disc 174 and the upper timing disc 192 are shown in greater detail in FIGS. 4 and 5 re- ,spectively. As shown in FIG. 4, the lower timing disc 174which'has its circular opening 176 aligned with and receiving an outer end portion of the roll pin 178 has a second circular opening 238 aligned with a passage 238a (FlG. 2.) through the front cover 18 and openings in the seals and 172 which open into a transverse slot 239 in one of the spokes 78b, displaced ninety degrees from the spoke, to permit fluid to flow from the annular space 240 within front cover 18 (FIG. 3). Circumferentially spaced projections 241(FIG. 4) on the outer periphery of the lower timing disc 174 are received in notches formed on the inner wall of the front rib 156 to prevent rotation of the disc 174 with respect to the cover 18. A very shallow circumferential groove 242, which communicates-with the opening 176 is provided in the upper surface of the lower timing disc 174.

The upper timing disc 192 includes three circumferential recesses 244 disposed in the outer periphery thereof and arranged to lock the upper timing disc 192 cess 246.1ea'ding-from a capillary groove 248 extending substantially completely around the lower surface of the upper timing disc 192 and overlying the opening 238. The three recesses 244 and their corresponding detents have different lengths to insure proper orienta 1 tion ofthe upper timing, disc 192-within the recess 184.

Thus a metered air passage from the exterior of the timer attachment is defined by gaps between the lower housing 23 and the contact blocks 44-46 of the relay to which the timer attachment is attached, the screw holes 161 (FIG. 14), radial'slots 163a, tubular passages 162, recess 163, filter 158, filter support 160, space 240, slot 239, passageway 238a through the front cover 18, aligned openings in the

seals

170 and 172, opening 238' in the lower timing disc 174, the capillary groove 248 around the upper timing disc 192, the oblong opening 246, the groove 242 around the lower timing disc 174, the opening 176 in the lower timing disc 174, and thence via the hollow interior of roll pin 178 and passage 84 to the cavity 96 above the flexible diaphragm 94.

FIGS. 8 and 9 show the timer attachment 10 with the offset foot portion 154 of the contact carrier 132 positioned for time delay after energization of an electromagnetic relay 250.-The relay 250 has the hollow housing 65 and, within the housing65, an electromagnetic coil 254, and an E-shaped magnetic core 256 which cooperates with an armature 258 having the relay contact carrier 48 secured thereto. Suitable'spacers 262 are provided between the mounting

lugs

24 and 26 and the carrier 48, a

When the relay 250 is de-energized, the relay contact carrier 48 is urged to its upper position by springs (not shown). Because of entrapment of the spindle portions 227-228 in the recesses 43, the rocker 14 has been ro- 'tated clockwise (as shown in FIG. 8) and the camming surface 234 has engaged the bottom surface of the offset foot 154 and pushed the carrier 132, and, therefore,

valve spindle 109, upwardly against the force of the compression spring 120. The diaphragm 94 is deflected upwardly and the volume of the chamber 96 is reduced. Upon energization of the relay 250, the armature 258 is attracted to the core 256 and the armature 258 and relay contact carrier 48 are moved rapidly downwardly as viewed in FIGS. 8 and 9 away from the offset foot 154. The rocker l4 isrotated counterclockwise, the hook arm 204 and rocker web 220 are rotated downof the pneumatic timer attachment will be further dewardly away from offset foot 154, while the rocker web 223 is rotated upwardly. The valve disc portion 108 is urged toward the valve seating surface ,104 on the flexible diagram 94 by the compression spring 122. The 'restricted flow of the air, as determined by the setting of adjusting knob 30, into the cavity 96 impedes the return of the diaphragm 94, the valve spindle 109, and the contact carrier 132 to their normal positions, thereby providing the desired time delay between energization of the relay and the opening of the

contacts

133, 134 and 138 and closing of

contacts

135, 136 and For time delay after de-energization, spring clips 66 are rotated from the clamping surfaces of 28 on

lugs

24 and 26, the timer attachment 10 is removed from the contact mounting blocks, is rotated 180 about a vertical axis, and is reassembled in place on the contact blocks with the attachment oriented as shown in FIG.

10 so that the offset foot portion 154 extends toward the rocker web 223. When the timer attachment 10 is positioned as shown in FIG. 10, and the relay 250 is energized, the contact carrier 48 and carrier insert 16 are moved rapidly downwardly, the rocker 14 is rotated counterclockwise and the web 223 of the rocker 14 is moved upwardly and engages offset foot 154 to urge disc portion 108 of valve spindle 109 upwardly against scribed.

During the resetting stroke of the timer attachment 10, the offset foot 154 of the contact carrier 132 is pushed upwardly by the cooperating

web

220 or 223 of V the rocker 14 against the bias of the compression spring 122 and causes the release valve defined by the orifice 100 and rim 104 in the center of flexible diaphragm 94 in conjunction with the disc poriton 1080f the valve spindle 109 to open against the force of the spring 122. Air passes through the valve from the cavity 96 into the cavity 98 which is open to the atmosphere via the passage 152. The spring 128 deflects the diaphragm 94 upwardly and the valve closes. As the carrier 132 moves upwardly, the toggle springs 148 and 150 are moved over center and the bridge 140 moves from the upper resultant of the force exerted by the spring 122 and theopposition of the toggle springs l48 and 150. Thus the need for the aforedescribed adjustment screw 1 14. This movement is restained by the flexible diaphragm 94 because of the partial vacuum thereby created in the cavity 96. The pressure drop in the cavity 96,.relative to the surrounding atmospheric pressure, causesthe air to flow through the adjustable restrictive path into the cavity 96.

A timing capillary path is defined by the groove 248 around the underside of the upper timing disc 192. The effective length of the capillary is adjusted by rotation of the adjusting knob 30 which rotates the upper timing disc 192 with respect to lower timing disc 174. The rotation of adjusting the knob 30 and the upper timing which terminates in the opening 246 through the upper timing disc 192.. The opening 246 is in turn connected with the groove 242 which extends circumferentially around the upper surface of the lower timing disc 174. The minimum time delay is provided when the adjusting knob 30 is rotated so that the letter A (FIG. 14)

thereon is adjacent a raised triangular pointer 269 on the front cover 18 and increases to the maximum time delay as the adjusting knob 30 is rotated clockwise until the letter -G on the adjusting knob 30 is adjacent triangular pointer 269(Further rotation beyond the letter G to the letter A again passes through 'a zone where the timer period is of extended duration because there is no groove in the upper timing disc 192 but this delay is outside the normal range of the timer.

The groove 248 is progressively widened toward the end at which it communicates with opening 246 to pro- 9 vide a more linear relationshipbetween the angular position of the adjusting knob 30 and the time delay period than would exist if the groove 248 had a constant width. I e

Although the timing attachment 10 is herein described for use with a relay having contact blocks 44 and 46 and a relay carrier 48 with movable contacts, it will be understood if instantaneous contacts are not needed, a different and shorter movable part may replace the carrier 48 and spacers may replace the contact blocks 44-46.

FIG. 11 shows a manually operable timer attachment constructed in accordance with the invention. The timer 270.has a modified lower housing 272 (without the two lower securing lugs) having two

side bosses

274 and 276 with screws 278 therethrough and extending through openings therein to secure an adapter plate 282. which carries an operator, generally designated 284, having a push button 285 and a plunger 286 arranged to be manually actuated by the push button 285 and normally biased downwardly by a spring (not shown). This embodiment of the invention permits the timed contacts to be operated instantaneously by depressing the push button 285 and to be reset after a preset time when the push button 285 is released.

I claim:

1. A time relay apparatus comprising a housinghav ing a recess, a flexible diaphragm closing an open end of the recess and thereby defining a chamber, metering means permitting fluid to enter the chamber at acontrolled rate, a valve including an exhaust port opening in the diaphragm and a valve closure means normally in engagement with the diaphragm .for' closing the exhaust port opening, resilient means transmitting a force which normally holds the valve closure means in engagement with the diaphragm aboutthe exhaust port opening thereby ,to close the valve, valve actuating means extendingthrough the exhuast port opening, being 'guided atone portion by a wall of the housing, and being movable to move the valve closure means out of engagement with the diaphragm against the bias of the resilient means, thereby to open the valve, means,

the diaphragm from its normal position to reduce the volume of the chamber while fluid flows rapidly from the chamber through the exhaust port opening.

2. Apparatus according to claim 1 wherein adjustment means are provided for adjusting the force transmitted by the resilient means.

3. Apparatus according to claim 2 wherein the adjustment means is accessible from outside the housing.

4. Apparatus accordingto claim 1 wherein the reacting means includes means operative upon a predetermined reduction in the volume of the chamber to close the valve, and means operative to permit return of the diaphragm to its normal position at a rate controlled by the rate of entry of fluid into the chamber through the metering means.

5. Apparatus according to claim 1 wherein the apparatus is a timing attachment for an electromagnetic relay having a movable armature means, said actuating means having an end portion that extends through an opening in said wall of the housing and having an end face exposed outside the housing, driving means are provided to engage said end face of the actuating means to drive the actuating means in a direction to open the valve, and the driving means comprises a rocker carried by an insert secured to said armature means of the relay.

6. Apparatus according to claim 5 wherein said end portion of the actuating'means extending outside the housing has a foot portion extending laterally from one side thereof, and said end face is on the foot portion.

7. Apparatus according to claim 6 wherein the timing attachment is securable on the relay in each of two turned positions, selectively, the rocker has two actuator engagement surfaces disposed respectively on opposite sides laterally of the path of movement of the actuating means, one of the actuator engagement surfaces being positioned to engage said end face in one of the turned positions of the timing attachment and the other actuator engagement surfaces *being positioned to engage said end face in the other turned'position of the timing attachment.

8. Apparatus in accordance withjclaim 7 wherein the,

actuator engagement surfaces are atoppo'sit'e ends of the rocker, respectively, the rocker is pivoted at one end to the insert and is rotatably secured intermediate its ends to the housing at an axis whereby, when the insert is moved by the armature means, the rocker rotates about the axis to move one of its engagement surfaces into engagement with said end face thereby to effect movement of the actuating means. i I

9. Apparatus in accordance with claim 1 wherein a snap switch is provided, and the actuating means includes means for operating the snap switch.

10. Apparatus in accordance with claim 8 wherein the actuating means has a fulcrum portion, and the snap switch comprises a contact bridge mounted at said fulcrum portion and spring means for moving the contact bridge with'a snap action upon movement of the actuating means.

11. A time delay apparatus according to claim 1 wherein the metering means comprises a first and a sec ond timing disc in face-to-face engagement with 'each other; the first timing disc is fixedly retained in a wall of the housing; a rotatable adjustment knob is pro vided; the second timing disc is fixedly retained on the knob; the first timing disc has an annular groove facing the second timing disc, a first orifice therethrough positioned away from the annular groove and a second orifice therethrough intersecting the annular groove; the second timing disc has a circular capillary groove facing the first timing disc; and a generally radial recessat.

one end of the capillary groove leading to the annular groove in the first timing disc; and the capillary groove is positioned in alignment with the first orifice in the first disc, whereby relative rotation of the first and second timing discs causes a change in the effective length of the capillary groove extending from the first orifice in the first timing disc to the recess ,in the second timing disc.

12. Apparatus in accordance with claim 11 wherein the capillary groove varies in effective cross-section alongits length so that the rate of change of the amount of fluid flow through the capillary groove is substantially in linear relationship to the relative rotation of .the timing discs.

13. A time delay apparatus according to claim, 11

wherein the first orifice in the first timing disc providesan inlet passage to the metering means from the atmosphere, and the second-orifice in'the first 'tim ing'disc provides chamber.

' w in t an "outlet from the metering means to the" (5:23 r UNITED Sims mm sgig f'f CERTIFSIQATE QFCORRECTIQN 7100 Dated b r 1 7 "Paced; no.

j iDavid", likarr a' man Cook Inventor) 1 L l It is certified error appears in' the above-identified petent I and that said Letters Patent are hereby corrected as shown below:

Columri 6, Lin e 48, after "spoke" insert ,-;7 8a--.

"si ned a m sealed this 16th day ofApr il 1971;,

, E-A Ate-est:

EDWARD M. 1='L1e:TcHER ,iJR. f Y 1 1 r c. MARSHALL DANN I tt sti Officer; I I I CommissionerofyPatents P0405) UNITED STATES PATENT ()FFICE CERTIFECATE OF CORRECTIUN Patent 3,775,71o Dated November 27, 1973 David Langman Cook Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, Line 48, after "spoke" insert -78a-.

Signed and sealed this 16th day of April 19m.

(SEAL) Att'est:

EDWARD M.FLI13TCHER,JR. C. MARSHALL DANN Atte sting Officer Commissioner of Patents

Claims

1. A time relay apparatus comprising a housing having a recess, a flexible diaphragm closing an open end of the recess and thereby defining a chamber, metering means permitting fluid to enter the chamber at a controlled rate, a valve including an exhaust port opening in the diaphragm and a valve closure means normally in engagement with the diaphragm for closing the exhaust port opening, resilient means transmitting a force which normally holds the valve closure means in engagement with the diaphragm about the exhaust port opening thereby to close the valve, valve actuating means extending through the exhuast port opening, being guided at one portion by a wall of the housing, and being movable to move the valve closure means out of engagement with the diaphragm against the bias of the resilient means, thereby to open the valve, means reacting between the actuating means and the diaphragm and operative upon opening of the valve to flex the diaphragm from its normal position to reduce the volume of the chamber while fluid flows rapidly from the chamber through the exhaust port opening.

4. Apparatus according to claim 1 wherein the reacting means includes means operative upon a predetermined reduction in the volume of the chamber to close the valve, and means operative to permit return of the diaphragm to its normal position at a rate controlled by the rate of entry of fluid into the chamber through the metering means.

6. Apparatus according to claim 5 wherein said end portion of the actuating means extending outside the housing has a foot portion extending laterally from one side thereof, and said end face is on the foot portion.

7. Apparatus according to claim 6 wherein the timing attachment is securable on the relay in each of two turned positions, selectively, the rocker has two actuator engagement surfaces disposed respectively on opposite sides laterally of the path of movement of the actuating means, one of the actuator engagement surfaces being positioned to engage said end face in one of the turned positions of the timing attachment and the other actuator engagement surfaces being positioned to engage said end face in the other turned position of the timing attachment.

8. Apparatus in accordance with claim 7 wherein the actuator engagement surfaces are at opposite ends of the rocker, respectively, the rocker is pivoted at one end to the insert and is rotatably secured intermediate its ends to the housing at an axis whereby, when the insert is moved by the armature means, the rocker rotates about the axis to move one of its engagement surfaces into engagement with said end face thereby to effect movement of the actuating means.

10. Apparatus in accordance with claim 8 wherein the actuating means has a fulcrum portion, and the snap switch comprises a contact bridge mounted at said fulcrum portion and spring means for moving the contact bridge with a snap action upon movement of the actuating means.

11. A time delay apparatus according to claim 1 wherein the metering means comprises a first and a second timing disc in face-to-face engagement with each other; the first timing disc is fixedly retained in a wall of the housing; a rotatable adjustment knob is provided; the second timing disc is fixedly retained on the knob; the first timing disc has an annular groove facing the second timing disc, a first orifice therethrough positioned away from the annular groove and a second orifice therethrough intersecting the annular groove; the second timing disc has a circular capillary groove facing the first timing disc; and a generally radial recess at one end of the capillary groove leading to the annular groove in the first timing disc; and the capillary groove is positioned in alignment with the first orifice in the first disc, whereby relative rotation of the first and second timing discs causes a change in the effective length of the capillary groove extending from the first orifice in the first timing disc to the recess in the second timing disc.

12. Apparatus in accordance with claim 11 wherein the capillary groove varies in effective cross-section along its length so that the rate of change of the amount of fluid flow through the capillary groove is substantially in linear relationship to the relative rotation of the timing discs.

13. A time delay apparatus according to claim 11 wherein the first orifice in the first timing disc provides an inlet passage to the metering means from the atmosphere, and the second orifice in the first timing disc provides an outlet from the metering means to the chamber.