US2662594A

US2662594A - Time delay relay

Info

Publication number: US2662594A
Application number: US278283A
Authority: US
Inventors: Carl A Schaefer
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1952-03-24
Filing date: 1952-03-24
Publication date: 1953-12-15
Anticipated expiration: 1970-12-15

Description

Dec. 15, 1953 c A. SCHAEFER 2,662,594 TIME DELAY RELAY Filed March 24, 1952 3 Sheets-Sheet 1 Y mm- IN V EN TOR. 6142'] 27 ac'zdei erf AV'TOFA/IK C. A. SCHAEFER TIME DELAY RELAY Dec. 15, 1953 3 Sheets-Sheet 2 Filed March 24, 1952 Dec. 15, 1953 c. A. SCHAEFER TIME DELAY RELAY 3 Sheets-Sheet 3 Filed March 24, 1952 INVENTOR. adr/fldc/gdefez grfokwzk Patented Dec. 15, 1953 I TED IS TATES Pfiiilifll"I OF F I'CE eon schpefen lviilwauiee, is" to a s me!) 100mm.

flaunt-Michigan Detroit, Mich, a, corpora- This invention relates 'eutometic uining mec'hanisms having Ladjustableitime 'deiay means Efo'r "warying the operation 'ofi'rthe mechanism; more specifically, this invention relate to an adjustable timing mechanism :forthe attainment of :either a 'substantially lmear relationship between ithe timed period and th'e stting *of the -"eontro11in'g element or' other -15redetermined relati'nship's, the timing tp'eriod 'being =th'e smne "re- :gardless of from "which directionoa. setting is .ima'de.

-One ob'jec't of the present inV'ention -is toiprovi'de an improved adjustable timihg m''ehanis'rn wherein therrelationship abetween 'the delay "time and "the "setting of the *timing controller 153Gbistaritia-lly linear and is unaffe'tedaby hacklfish, the term being usedrher'ein to indicate a difierence in timing :period when the same "setting is made from opposite directions.

Another object of the present invention =the provision of :an improved adjusteble *tiffle eeley rielayrin which the *time delay is yar'ied by varying the effective length of -a timing groove through which the timing air 'fiows.

Another object "of the invention is the provision of an improved adjus'table timing device inaccordance with the preceding'objeet in which a capillary timing groove is spro'vided inwme of Ta, pair of closely mating surfaces, the timing air flowing through continuously adjustable lengths of the timing groove :to effect the timing operaition.

:Another object of theinventibn is the provision TOf an adjustable timing -dev-ice 4n accordance with the :preceding object-in which a pair of cir- "oularelements having closely matting surfaces are provided, one of the-elements being rotatable and having a capillary groove therein anden'aoertm'e communicating the groove with the atmosphere, the other element having an aperture communicating its mating surface with the interior 'of the timing chamber and so positioned as to register with the timing groove as the rotatable element is rotated, whereby the effeotive distance of the timing groove throughwhich the timing af'r must pass may be varied to determine the Another object of the invention is the provision of arnedjustable timin device employing new of timing air through a timing gro'oi e of nobuniform cross sectional area to pro'yide any desired relationshipebetween the timing period one the setting movement, the eiieetiveienigth or the groove being continuously adjustable.

Other objects and reamre s or the g I, will be readily apparent to, those R1 ed lithe m from the p ci oat oh 311d appetite ioveiitioh his '2 lnis mumsemg certain :preferred'embbdinfnts In which:

mouse 1 'is a *front' elevati'oiim 'view of "aif'fxi-lcel relaiyfinckirfiratirig the timing-mechanism ofthepresentinvention. A

Figure 2 "is an "enlarged "sectional "View *ilofig "the 1i!f& II- HOf Ffgi1rb 1.

Figure =3 is n "reduced s'ectibnall "View aiong the imes il-H 111 of Figure '2.

Pigiire'i' is a redueei l sectional view'along'the qins -N- IV ef Figure 2.

Figiiie '5 is 9 a redued Secti'onall view *alOHg the lines V-V of Figure 2. g v

' mgure t rs 'a 1f'ed\led sectional "view erongthe -=iine w -VI of Fig'u'rez w r Figure 7 'is an enlarged sectional view elbifg theiines ot- F'i'gure 6.

*Ffeuree is s. reuued sectional view along the ime VIH V1I-I"0f Figure 2. v N

figure?! is '"a yiew sir'nilar to Figure '4, with the i urteeifrereritiy'eosinoned. v v

ID and l l snow modifications 6f the "ipart's shown in l lg'iirefi.

Tne=dev1ceor the =i$reSent invention comprises 7 a valve 1., haying upper and lowerehefn hers 10 end 20; resoeetiyeiy, therein. he upper norti'on oif eha'rii-ber I0 is'c'ldsedby acoivei' 2 having "holes "I therein 'ror iiefniitting or; to pass into tiieehdmber 10, a. filter 4 being interposeq between "the "em/er '2 im'd the Valve base] to filter 'the i'ncomii'lg sir. Extending through the 'er1"tr'a .l oiihfiig in 'tn oov'er 2 is an upstanding snort I of! Viflye wheel 6, he Shaft 'S being joined by a 'pfii 1 to a i'dtettbl'e dial 8 which carries "on ihflfciwbairihg trial chart 9.

may t from Figure 4, extending aim the valve v ifeel 6 about the central nortneieorere three large h les |2, the nor;- is'ose o; White Will jsoesequentiy he explained; 'a 'sifi'fe hole 11 extends through the verve wheel 6 near the periphery thereof. T-h'e lower serrate 'cfiom me view or h gure z) or valve vvheei s is provided vitii *oop'ine'ry timin roove 1;: which, sheen n Fignr 3-, has one end communicati g "With the nerve "r nd which extends in teenenuy ireiii'firjiith (with the center 'of rotation "16 as the tent-er) stout 330 Q 'in 'a circular identa'tion f4 extend through the valve tvh'e t.

does not g g t h or invo ve w en i "item; the iipioer some ore stationaryvai i bit eijiiatm'g-sm r g n we e ee 1 ieeveeevme pm ting "-i'eiitive move 'A ingl -hotels extends through the valve 11mg I5 and is sodfst that the timing groove it of valve wheel 6 will pass over the center of the hole I5 as the valve wheel 6 is rotated. interposed between the valve ring I5 and a ledge of the base I is a flexible diaphragm I? which has a hole I 8 in alignment with the hole It of the valve ring [5. As may be seen from Figures 6 and '7, the valve wheel l5 and the diaphragm] l! are fixedly mounted to the base I by means of dowels 19.

A tight seal is effected between the valve wheel 6 and the valve ring l5, and between the valve ring l5, diaphragm i1 and base i by a springwasher 8! which is interposed between a central hub on the cover 2 and the upper surface of the valve wheel ii. I

Interconnecting the upper and lower chambers ill and 2c of the valve base I are a pair-of channels 2i and 22, the channel 2| cooperating with the hole I8 in the diaphragm H, the channel 22 serving a purpose to be subsequently explained.

.-' The central portion of the diaphragm I1 is provided with a pair of stifiening washers 23 disposed on opposite sides thereof and which sur round a ferrule 24 of substantially rigid material which is provided through the center of the dia The lower portion of the ferrule 24 is provided with a thin, circular valve seat 25, a spring 25 being interposed between the ferrule 24 and the valve wheel 6 to bias the valve seat 25 into engagement with a valve disc 2i which, with an associated retainer, rests in a central recess in the valve base I,'as shown in Figure 2.

It will be seen'that when the valve seat 25 is in contact with valve disc 21, no air may pass from the chamber H] above the diaphragm i! to the chamber below'that diaphragm except by the path through the channel 2|, hole l6 and either hole H or the hole II and timing groove I 3 depending upon the relationship between valve wheel 5 and valve wheel [5. On the other hand,

-when valve seat is lifted from thevalve disc 2?, free access is provided for air flow through the open center of the ferrule 24 and channel 22.

The valve base I is rigidly mounted upon a -main base 28. Interposed between the valve base i and the main base 28 so as to define the lower boundary of chamber 29 are a flexible diaphragm 2i! and a sealing gasket 3|. The central portion of the diaphragm 29 is provided with stiffening washers 32 at its opposite sides and a movablebracket 33 is connected thereto by means of a riveted or spun over element 34. The bracket 33 extends through a suitable hole 35 in the main base 28 and is fixedly mounted by screws 36 to a block 3?. A spring 38 is interposed between the lower surface of the base 28 and the block 37 to bias the block 31 away from the base. Th spring 35 surrounds a bossed section 39 of the base 28 carrying a guide pin M which projects through block 37 and into a suitable recess in a bumper 62, which is fixedly mounted to an armature lever 52, to be more fully described later.

The timing mechanism has been shown with an operator for an electric switch, shown gen- Associated with the timing mechanism, in the I,

specific embodiment shown, there is an electromagnetic operator comprising an E-shaped field magnet 41 provided with an energizing coil 55 and adapted to attract a T-shaped armature member 55. The armature member 59 is pivotally mounted at 5| to the aforementioned armature lever 52. The armature lever 52 has an upstanding flange 53 slidably disposed within slot in upper guide plates 54 which are in turn rigidly mounted on a mounting plate 55. An

armature guide plate 56, together with the guide ator- 62- disposed so as to be reciprocated by an extension 63 of the armature lever 52.

The operation of the timing relay is as follows:

Energization of the solenoid 53 causes armature 19 to move downwardly against the bias of the reset spring 58. Armature as carries armature lever 52 downwardly carrying therewith the bumper 42. As bumper 42 moves away from diaphragm block 31, spring 38 will tend to move diaphragm block 31, and the bracket 33 on which it is mounted, downwardly. The rate of this downward movement is dependent upon the rate of movement of diaphragm IT, to which bracket 33 is also attached. With the valve wheel 6 in the position illustrated in Figure 2, air will pass through the holes 3 in cover 2, filter t, directly through the hole I l in valve wheel 6 and thehole it in valve disc l5, hole H8 in diaphragm H and through channel 2| to the chamber 29 above diaphragm 29, which will therefore rapidly move downwardly under the bias imparted thereto by spring 38. Downward movement of diaphragm block 37 will effect rotation of the arm and member 51 to thereby effect operation of the switch mechanism 43. Downward movement of the extension 63 of the armature lever 52 is always without delay'to effect immediate operation of the electrical interlock 6!. It should be noted that the position of parts of Figure 2 will produce the minimum timed period.

When, on the other hand, the valve wheel 5 is rotated (as, for example, to the position of Figure 9) so that aporticn of the timing groove id, rather than the hole H, is over the hole !5 in the valve wheel 15, when diaphragm 25 is urged downwardly by bracket 33 under bias of spring 313, timing air will pass through the hole H into the timing groove IE to the hole i5 and then through holes I5 and I8 and channel 2% into the chamber 28. As earlier indicated, the engaging surfaces of the valve wheel 6 and the valve ring are so finished that air is excluded from the timing groove l3 everywhere except through the hole I l in the valve wheel. It will, therefore,

capillary timing groove is is so large that the rate at which the air flows is directly proportional to the length of the path through which it must flow, the rate at which air is permitted to enter the chamberZD above the diaphragm 29 is directly dependent upon the effective length of the timing groove. That is to say the length of the ltiming groove through which the incoming air ,rnust pass directly ermines the rate at which ir enters the diaph a m ;c.h mb Hen e, #85

Wheelfi is rotated to vary the length of gropve 1.3 between holes ll and t6,- the timing period will p op rt na ly and fst pl wver It should also be noted that with the valve wheel 5 so positioned tht the flat surface of wheel 6 between the hole It and the depression l4 covers the hole it .of the valve disc l5, no air whatsoever would be permitted to enter the chamber 20, which therefore could not expand nel 2'2 and, acting upon the large area of the diaphragm I! will lift the valve seat 25 from the valve disc 21, the air thereby being admitted to the space above the diaphragm H and escapin to the outer atmosphere through the felt filter 4 and the holes 3 of the cover 2. After this air has been forced out, the valve seat 25 recloses upon the valve disc 21 under the bias of spring 26. It will be seen that due to the large effective area of the diaphragm 11, the force required to open the valve is very small. Further, the large area .of the diaphragm l1 also serves to cause a-relatively large force to be exerted by the small valve seat 25 upon the valve disc 2"! during the timing period when the chamber 29 above the diaphragm 29 is under a partial vacuum.

It will be seen that for any setting .of the dial 8 and the associated valve disc 6, the rate at which fluid can pass into the chamber above the diaphragm 29 to permit its downward movement is directly dependent upon the length of the tim ing groove 3 through which the timing air must pass. It will further be seen that the timing period is unaffected in any way by backlash in the device, the timing period being exactly the same at any predetermined setting of the valve wheel -6, regardless of the direction of rotation of the valve wheel to reach that setting.

It is obvious that the materials from which the valve wheel 6 and the valve ring i5 are made must be such that a solid, smooth finish may be placed upon the mating surfaces thereof; furthermorc, these surfaces should be corrosion re sistant and any sticking tendency should be minimum. While many substances may be emlo d. as a s ifi e pl a v l e wheel of di ca uminum th a va e r n o eithe nickel-silver or a non rnetallic material have been fo nd o be su a le- It will further be seen that the timing groove is wi d be u in h al e rin in ead of i the valve wheel 5 as illustrated, without changing the characteristics of the device.

Referring to Figures 10 and ll, there are illustrated therein two modifications of the timing groove to achieve special timing characteristics. In Figure 10, for example, there'is shown a valve wheel Hi8 (similar to wheel 6 already described) having a tapered timing groove li3 cut therein h ch e m n n a h e I I l exten g t rou h h el g r 11 re i illustrated a valve heel 2 6 a o imil to heel in wh ch a tep d im n g o e are i o t. r ove. 2E3 terminating in hole 3 l I extending through wheel h th o hese modified timing grooves, as

:well as :cthers fljhOSgaSkfllGd; in the art-will readily perceive, will produce special relationships between timing and setting movements w ch ma the desiredp o iexamp e to-expan th movem ntandscal etoer ainrra e swh ilecertain preferred embodiments of-the in- ,vention have been specifically disclosed, it-is understood thattheinvention is notlimited thereto, as many 1v. o s wil be read appar nt to those-skilled ingthe artand-the invention is to be givenits broadest possible interpretation within he terms of the iollowing c m Wha {is cla med is:

.In .a tunin -devic compr a var a volume' chamzber and means movable to change said cha ber "volume-and effect a control function,-;means @forcontrol ing the rate of movement of said movable :means to determine a timed period eomnrising,.a:pai1- of relatively movable members each having both an aperture extending therethrough and at least one flat surface, a capillary groove in one of said surfaces, said groove communicating with one of said apertures, the other .of said apertures communicating with any and all selected portions of said groove, means maintainingsa-idsurfaces in close engagement, means for moving one of said relatively movable members to effect a sliding movement between said flat surfaces, and thereby position- ;ing a :stepless, continuously varying length of said capillary groove between said apertures.

2. .In a timing device comprising a variable volume chamber and means movable to change said .chamber volume and effect a control function, means for controlling the rate of movement of said movable means to determine a timed period comprising, a rotatable member and a fixed member each having :both an aperture extending therethrough and at least one flat surface, .a capillarygroove .in the flat surface of said rotatable member, said groove being symmetrically disposed about the axis of rotation of said rotatable member, the aperture in said rotatable member communicating with one portion of said capillary groove, the aperture in said fixed mem ber being positioned to communicate with said capillary groove, means maintaining said flat surfaces in close engagement, and means for rotating said rotatable member to effect a sliding movement between said fiat surfaces and a progressively changing relationship between said two apertures,..whereby a continuously varying length of said capillary groove may be positioned between said apertures.

3.'In a timing device comprising a variable volume chamber and means movable to change said chamber volume and effect a control function, means'for controlling the rate of movement of said movable means to determine a timed period comprising, a pair of relatively movable members each having both an aperture extending therethrough and at least one flat surface, a capillary groove in one of said surfaces, said groove communicating with one of said apertures, the other of said apertures communicating with any and all effective portions of said groove as desired, means maintaining said surfaces in close engagement, means for moving one of said relatively movable members to effect a sliding movement between said flat surfaces, and means for positioning a step'less, continuously varying length of said capillary groove between said apertures, said capillary groove being of constant cross sectional area throughout its length whereby a linear relationship between the timed period and the length of said groove between said apertures exists.

4. In a timing device comprising a variable volume chamber and means movable to change said chamber volume and effect a control function, means for controlling the rate of movement of said movable means to determine a timed period comprising, a rotatable member and a fixed member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of said rotatable member, said groove being symmetrically disposed about the axis of rotation of said rotatable member, the aperture in said rotatable member communicating with one portion of said capillary groove, the aperture in said fixed member being positioned to communicate with said capillary groove, means maintaining said fiat surfaces in close engagement, and means for rotating said rotatable member to effect a sliding movement between said flat surfaces and a progressively changing relationship between said two apertures, whereby a continuously varying length of said capillary groove may be positioned between said apertures, said capillary groove being of constant cross sectional area throughout its length to provide a linear relationship between the timed period and the length of said groove between said apertures.

5. In a timing device comprising a variable volume chamber and means movable to change said chamber volume and effect a control function, means for controlling the rate of movement of said movable means to determine a timed period comprising, a rotatable member and a fixed member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of one of said members, said groove being symmetrically disposed about the axis of rotation of said rotatable member, one of said apertures communicating with said groove and the other of said apertures communicating with selected portions of said groove, means maintaining said surfaces in close engagement, and means for rotating said rotatable member to effect a sliding movement between said fiat surfaces and position a continuously varying length of said groove between said apertures.

6. In a timing device comprising a variable volume chamber and means movable to change said chamber volume and effect a control function, means for controlling the rate of movement of said movable means to determine a timed period comprising, a rotatable member and a fixed member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of one of said members, said groove being symmetrically disposed about the axis of rotation of said rotatable member, one of said apertures communicating with said groove and the other of said apertures communicating with selected portions of said groove, means maintaining said surfaces in close engagement, and means for rotating said rotatable member to effect a sliding movement between said flat surfaces and position a continuously varying length of said groove between said apertures, said capillary groove being of constant cross sectional area throughout its length to provide a linear relationship between the timed period and the length of said groove between said apertures.

7. In a timing device comprising a variable volume chamber and means movable to change said chamber volume and eifect a control function, means for controlling the rate of movement of said movable means to determine a timed period comprising, a rotatable member and a fixed member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of one of said members, said groove being symmetrically disposed about the axis of rotation of said rotatable member, one of said apertures communicating with said groove and the other of said apertures communicating with selected portions of said groove, means maintaining said surfaces in close engagement, and means for rotating said rotatable member to efiect a sliding movement between said flat surfaces and position a continuously varying length of said groove between said apertures, said capillary groove being of progressively varying cross-sectional area to provide an exponential relationship between the timed period and the length of said groove between said apertures.

8. In a timing device comprising a variable volume chamber and means movable to change said chamber volume and effect a control function, means for controlling the rate of movement of said movable means to determine a timed period comprising, a rotatable member and a fixed member each having both an aperture extending therethrough and at least one fiat surface, a capillary groove in the flat surface of one of said members, said groove being symmetrically disposed about the axis of rotation of said rotatable member, one of said apertures communicating with said groove and the other of said apertures communicating with selected portions of said groove, means maintaining said surfaces in close engagement, and means for rotating said rotatable member to effect a sliding movement between said fiat surfaces and position a continuously varying length of said groove between said apertures, said capillary groove being of one cross-sectional area over a portion of its length and a different cross-sectional area over the remaining portion of its length to vary the relationship between the change in the timed period and the change in the length of said groove disposed between the apertures.

9. In a timing device, a chamber, means movable to effect expansion and contraction of the volume of said chamber, means biasing said first mentioned means for movement in one direction, means for moving said first mentioned means in the opposite direction against said biasing means, means for providing free passage of air from said chamber as said movable means moves in one direction, and means for varying the rate of air flow into said chamber as said movable means is moved in another direction for determining the timed period, said last mentioned means comprising a pair of relatively movable members each having both an aperture extending therethrough and at least one flat surface, a capillary groove in one of said surfaces, and means maintaining said flat surfaces in close engagement, one of said apertures communicating one portion of said groove with said chamber and the other aperture communicating one portion of said groove with the atmosphere, movement of one of said relatively movable members effecting a sliding movement between said flat surfaces and a progressively changing relationship between said two apertures whereby a continuously varying length of said capillary groove i positioned between the atmosphere and said chamber.

In a timing device, a chamber, means movable to effect expansion and contraction of the volume of said chamber, means biasing said first mentioned means for movement in one direction, means for moving said first mentioned means in the opposite direction against said biasing means, means providing free passage of air from said chamber as said movable means moves in one direction, and means for varying the rate of air flow into said chamber as said movable means is moved in another direction for determining' the timed period, said last mentioned means comprising a pair of relatively movable members each having both an aperture extending therethrough and at least one fiat surface, a groove in one of said surfaces having a progressively varying cross sectional area, and means maintaining said flat surfaces in close engagement, one of said apertures communicating one portion of said groove with said chamber and the other aperture communicating one portion of said groove with the atmosphere, movement of one of said relatively movable members'effectin'g" a sliding movement between said flat surfaces and a progressively changing relationship betwensaid two apertures whereby a continuously varyinglength of said groove is positioned between the atmosphere and said chamber.

11. In a timing device, a chamber, means movable to efiect expansion and contraction of the volume of said chamber, means biasing said first mentioned means for movement in one direction, means for moving said first mentioned means in the opposite direction against said biasing means, means for providing free passage of air from said chamber as said movable means moves in one direction, and means for varying the rate of air flow into said chamber as said movable means is moved in another direction for determining the timed period, said last mentioned means comprising a pair of relatively movable members each having both an aperture extending therethrough and at least one flat surface, a groove in one of said surf-aces, said groove having one cross sectional area over a portion of its length and a different cross sectional area over the remaining portion of its length, and means maintaining said flat surfaces in close engagement, one of said apertures communicating one portion of said groove with said chamber and the other aperture communicating one portion of said groove with the atmosphere, movement of one of said relatively movable members effecting a sliding movement between said flat surfaces and a progressively changing relationship between said two apertures whereby a continuously varying length of said groove is positioned between the atmosphere and said chamber.

12. In a timing device, a chamber, means movable to effect expansion and contraction of the volume of said chamber, means biasing said first mentioned means for movement in one direction, means for moving said first mentioned means in the opposite direction against said biasing means, means for providing free passage of air from said chamber as said movable means moves in one direction, and means for varying the rate of air flow into said chamber as said movable means is moved in another direction for determining the timed period, said last mentioned means comprising a fixed and a movable member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the fiat surface of said movable member, and means maintaining said fiat surfaces in close engagement, the aperture in said movable member communicating one end of said capillary groove with the atmosphere, the aperture in said fixed member communicating said capillary groove with said chamber, movement of one of said movable members effecting a sliding movement between said flat surfaces and a progressively changing relationship between said two apertures whereby a continuously varying length of said capillary groove is positioned between the atmosphere and said chamber.

13. In a timing device, achamber, means movable to effect expansion and contraction of the volume of said chamber, means biasing said first mentioned means for movement in one direction, means for moving said first mentioned means in the opposite direction against said biasing means, means for providing free passage of air from said chamber as said movable means moves in one direction, and means for varying the rate of air flow into said chamber as said movable means is moved in another direction for determining the timed period, said last mentioned means comprising a fixed and a rotatable member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of said rotatable member, said groove being symmetrically disposed about the axis of rotation of said rotatable member, and means maintaining said fiat surfaces in close engagement, the aperture in said rotatable member communicating one portion of said capillary groove with the atmosphere, the aperture in said fixed member being positioned to communicate said capillary groove with said chamber, rotation of said rotatable member effecting a sliding movement between said flat surfaces and a progressively changing relationship between said two apertures whereby a continuously varying length of said capillary groove is positioned between the atmosphere and said chamber.

14. In a timing device, a chamber, means movable to effect expansion and contraction of the volume of said chamber, means biasing said first mentioned means for movement in one direction, means for moving said first mentioned means in the opposite direction against said biasing means, means for providing free passage of air from said chamber as said movable means moves in one direction, and means for varying the rate of air flow into said chamber as said movable means is moved in another direction for determining the timed period, said last mentioned means comprising a fixed and a rotatable member each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of said rotatable member, said groove extending in an arcuate path symmetrically about the center of rotation of said movable member, resilient means maintaining said flat surfaces in close engagement, an upstanding shaft projecting from said rotatable means, a dial mounted to said shaft for rotation therewith, and an indicia bearing chart mounted to said dial, one of said apertures communicating one portion of said groove with said chamber and the ther aperture communicating one portion of said groove with the atmosphere, rotation of said dial effecting rotation of said rotatable member whereby a sliding movement between said fiat surfaces occurs and a progressively changing relationship between said two apertures is effected so that a continuously varying length of said capillary groove is positioned between the atmosphere and said chamber.

one fiat surface, a capillary groove in one of said surfaces, and means maintaining said flat surfaces in close engagement, one of said apertures communicating one portion of said groove with said chamber and the other aperture communieating one portion of said groove with the atmosphere, movement of one of said movable members efiecting a sliding movement between said fiat surfaces and a progressively changing relationship between said two apertures whereby a continuously varying length of said capillary groove is positioned between the atmosphere and said chamber, and means responsive to movement of said movable means for efiecting a control function.

16. In a timing device, a chamber, means movable to effect expansion and contraction of the volume of said chamber, and means for varying the rate of air flow into said chamber as said movable means is moved in one direction for 12 determining the timed period including a fixed and a, rotatable metal disc, each having both an aperture extending therethrough and at least one flat surface, a capillary groove in the flat surface of said rotatable disc having one end communicating with the aperture therein, said capillary groove extending in a symmetrical arcuate path about the center of rotation of said rotatable member, means mounting and maintaining said discs with the flat surfaces in close engagement and with the aperture in said fixed disc communicating said groove with said chamber, rotation of said rotatable disc effecting a sliding movement between said flat surfaces and a progressively changing relationship between said two apertures whereby a continuously varying length of said capillary groove is positioned between said apertures, and means responsive to movement of said movable means for effecting a control function.

CARL A. SCI-IAEFER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,964,300 Perry June 26, 1934 1,983,227 Hall Dec. 4, 1934 2,323,115 Bryant June 29, 1943