US2929898A - Pneumatic timing device - Google Patents

Description

March 22, 1960 c. A. scHAEl-'ER PNEUMATIC TIMING DEVICE 2 Sheets-Sheet 1 Filed May 6, 1957 /7 Trax/vll? March 22, 1960 c. A. scHAEFER 2,929,898

PNEUMATIC TIMING DEVICE Filed May 6, 1957 2 Sheets-Sheet 2 C4737 /7 Sci/defer' Byfuv-b( WM PNEUh/IATIC .TIMING DEVICE Carl A. Schaefer, Milwaukee, Ws.,assignor to Square D Company, Detroit, Mich., a corporation of Michigan Application May 6, 19S7,`Serial No. 657,251 V17 Claims, (Cl. 200-97) This inventionrelates to-time -delayfapparaug :and more particularly to aA pneumatic ytime delay apparatus or-timer utilizing la exible diaphragm disposed between a pair oi chambers and suitable .for association with an electromagnetic operator and control ycontacts vto provide -a time delay between the energizationofthe operating coil and the operationvot the contacteer selectively, a time delay between the ldeenergization'of the operating coil and the operation of the contacts.

Prior timers of this general type havebeen characterized by relatively complex diaphragms and associated valve mechanisms which `are expensive to manufacture and require considerable space. lln the timer of `this invention, a single flexible diaphragm Vhaving an Vexhaust orilice cooperating with a .reciprocatable valve results in a `diaphragm and Yvalving arrangement `that permits the apparatus to he made smaller than prior .devices i 'similar type without loss of timing accuracy or material reduction in the force available-.to operate the contacts. l An `object ot the present invention is to :provide van 'improved pneumatic `time' delay apparatus.

Another `obiect is to provide a pneumatic time delay apparatus having an improved flexible diaphragm.

` Another object is ot provide` a pneumatic time delay i pparatus including ailexible diaphragm having an integral valve portion.

Another object is to provide an improved pneumatic time delay relay which is smallerandrrnore compact Ithan prior relays of similar timing range and capacity.

A time delay apparatus in accordance with this invention comprises a housing having a recess-closed -by a lieX- ible `diaphragm to define a chamber. A metering valve permits uid to enter the chamber at a controlled rate.`

The iaphragrn has a normally closed exhaust orifice. Means are rprovided t0 liex 'the diaphragm from lts normal position to reduce the -volume of the chamber and I.concurrently to open the oriiice to permit liuid to llow rapidly Vfrom the chamber while its volume is being renired States Patent Q duced and thereafter to close said oritice with the volume reduced. A .spring is operative to return the diaphragm toits normal position with `the orifice closed at a rate controlled by` the rate of entry of liuid into the charnb'er through the metering valve.

.Other objects and advantages of this invention will become apparent from the following description wherein reference is made to the drawings, in which Fig. l is a side elevation of a time delay `apparatus in accordance with this` invention Fig. 2 is a front elevation of the time delay apparatus of Fig. l.

Fig. 3 is a fragmentary side elevation of the .electromagnetic portion oi 'the apparatus of Fig. l. arranged Afor a different sequence of operation.

Fig. 4 is a sectionalview taken along the line IV--lV of Fig. 2 with the pneumaticroperating mechanism in its normal position.

Fig. 5 is a view similar to Fig. 4 showing the pneuv1'7. lportion 23 extending-into a centralropenin'g -in the` coil '1S and aV lower transverse portion 24 arranged for Coopvapparatus to a mounting surface (not shown). vA suitable reset means for a'pneumatic timing mechanism :12 is shown as a magnetic operator d3 secured tothe base -10 as by screws lil. The pneumaticl timing mechanism 212 is secured to the 'oase -ltlas by screws 16. in the` arrangement of Fig. l, the magnetic operator 13 comprises a 'U-shaped, laminated frame 17 supporting an operating coil lli provided with suitable terminals 1Q-and disposed between'depending leg portions 20 and A2110i lthe frame AV T-shaped, laminatedarmature l22 l'has a lvertical eration with :pole'faces 25 and 26 at the lower ends of the leg portions 7.0 and 2l, respectively. Each `of the pole faces 25 and 26 `is provided with a conventional shading coil 27.

hreferably, the -vertical portion 23-and the horizontal portion 24 of the armature 22 comprise laminations disposed between,andpivoted on, the legs 'of a U-shaped yoke 28, the legs of which extend through the coil 18 and through spaced `openings in a bight portion of the vframe 17. A bight portion 29 of the yoke 2S lextends transversely across the bight portion of the frame i7.

The coil .i8 is preferably encapsulated within a'rigid plastic housingis positioned between the leg portions 20 the arrangement of Fig. l is instantly pulled upward against the bias -ot the spring 32 and the bight portion 29er the yoke 2li engages an operating button 35 vat the `lower end of a reciprocatable operating shaft 36 'ofthe timing mechanism 12. The arrangement of Fig. l is for time delay after deenergization of the coil 18 as will be explained. When time delay after energization of the coil 18 is desired, the Vmagnetic assemblyorc Fig. lis invetted, as shown in Fig. 3. In Fig. 3, the spring 32 normally biases the vertical portion 23 'of the armature 22 against the operating button 35 and energization of the coil 18 instantly pulls the armature 22 downward against the bias'of the spring 32 and moves the vertical portion 23 away from the operating button 35. The timing mechanism 12 causes the operating shaft 36 to move downward at a timed rate after it has been released from engagement with the magnetic operator 13 as will be described.

The button 3S has a peripheral groove 37 receiving a 'follower 38 mounted at an inner vend portion of a lever 39 pivoted about a pin 40. Motion of the operating shaft 36 is thereby transmitted to a conventional snap switch 41 by the lever 39 which has an adjustable tappet 42 at its outer end for engagement with a switch operator 43 of the snap switch 41.

As Ashown best in Figs. 4 and 5, the timing mechanism l2 comprises an upper dish-shaped valve or pressure housing 48 .defining a truste-conical upper chamber '49 secured, as by screws S0, to a lower dish-shaped exhaust housing 51 defining a similar frusto-conical chamber 52, the larger diameters of the chambers being juxtaposed. ln accordance with this invention, a composite diaphragm 54 is interposed between the housings 48 and S1.

' The exhaust housing A51 is provided with -a plurality of circumferentially spaced exhaust ports 55,'on1y.one

of which is shown. The valve housing 48 is provided with a manifold 56 having a horizontal tapered bore 58 communicating at its inner end with an upper end portion of a bore 59 opening into the valve chamber 49. The tapered bore 58 accommodates a needle valve 60 having a complementary taper. A slot 62 is provided in the head of the needle valve 60 for screw driver adjustment, the valve 60 being threaded into a suitable hanged bushing 64 `which may be, for example, molded from nylon. Preferably, the bushing 64 is held in an enlarged outer portion 65 of the bore 58 by overhanging heads of screws 66 (Figs. 1 and 2) threaded into the valve housing. The screws 66 also serve to retain a box-like dust cover 68, preferably molded from plastic, which prevents dust accumulation on a porous bronze filter 69, yet permits free passage of air through an entry 78 and around the top of the manifold 56.

Air tiows through the entry 70 between the dust cover 68 and the top of the manifold 56 to the lilter 69 which is received in a cavity 72 formed in the upper surface of the manifold 56. The filter 69 is held in place by a retaining ring 74. A vertical bore 75 extends from the cavity 72 downward and communicates with the tapered bore 58 to permit air to flow from the filter 69 through the bore 58 where its flow into the chamber 49 is metered by the valve 60.

The diaphragm 54 comprises an annular metal disc 77 molded' integrally with an annular exible membrane 78, preferably of silicone rubber, and is interposed between the valve housing 48 and the exhaust housing 51 by having an integral bead 79 formed at the outer periphery of the membrane 78 and received between the juxtaposed faces of the housings 48 and 51. The diaphragm 54 thus is disposed between the chambers 49 and 52. The bead 79 is in the form of a downwardly turned peripheral flange and is received in an annular groove 80 formed in the upper face of the exhaust housing 51. The membrane 78 has an outer flexible portion 81 of reduced thickness and an inner valve portion 82. The valve portion 82 has an annular, upwardly turned ange section 83 detining a central circular orifice 84. An upper annular face of the ange section 83 lies in a plane substantially normal to the axis of the orifice 84 and has an annular sealing bead 85 of generally triangular cross section formed thereon. The annular metal disc 77 which has an upwardly turned flange 86 at its inner periphery, is molded into a thickened central portion of the membrane 78 and adds rigidity to the valve portion 82. f A valve seat 87, preferably molded from nylon, Vis threaded onto an upper end portion of the operating shaft 36. An enlarged, annular-lower surface 88 of the valve seat 87 cooperates with the bead 85 of the valve portion 82 of the diaphragm 54. The valve portion 82 is biased against the surface 88 by a conical, helical valve spring 89 disposed between the lower surface of the metal disc 77 and a retaining ring 98 suitably secured to the shaft 36. It is to be noted that, as the shaft 36 reciprocates, the retaining ring 90 and the valvexseat 87 reciprocate therewith whereas the valve portion 82 of the diaphragm 54 is free to move axially relative to the shaft 36 against the bias of the valve spring 89.

The operating shaft 36 extends through an axial bore 91 in the exhaust housing Si and is restrained for reciprocating motion by a bushing 92 received in a counterbored upper portion 94 of the bore 91. An upwardly extending portion 95 of the valve seat 87 slidably enters an axial bore 96 in the valve housing 48 with adequate clearance to allow air to flow around the extension 95 to prevent a dashpot action.

The operating shaft 36 is biased downwardly from the valve housing 48 by a conical operating spring 98 disposed between the bottom surface of the exhaust housing 51 and the operating button 3S which is secured -to the lower end portion of the operating shaft 36. Y

4 In the operation of the time delay apparatus, a timing cycle is initiated by raising the diaphragm 54 from its normal position of Fig. 4 to its raised position of Fig. 5. This movement is accomplished by exerting an upward force on the operating shaft 36, which, as it moves up-.

wardly, carries the central portion of the diaphragm 54 upwardly, the membrane 81 exing to permit this movement. in the embodiments of Figs. i and 2, the upward force is exerted by the armature 22 upon energization of the coil 18. In the embodiment of Pig. 3, the upward force is exerted by the spring 32 when the coil 18 is deenergized. Since the needle valve 60, which meters the ow of air into the upper chamber 49, is not suited for rapid exhaust of air from the chamber 49, rapid upward movement of diaphragm 54- increases the air pressure in the chamber 49, progressively restraining further movement of the diaphragm. However, since the operating shaft 36 and valve seat 87 have a relatively small surface area, they are not materially affected by the increased pressure in the chamber 49 and rise above the valve portion 82 of the diaphragm 54. When the valve seat 87 Yseparates from the valve portion 82, the entrapped air in the chamberv49 escapes through the orifice 84 and exhausts to the atmosphere through the ports 55. When the pressure differential between the chambers 49 and 52 is relieved, the bead of the valve portion 82 reengages the lower surface 88 of the valve seat 87 in response to the bias of the valve spring 89.

The timing mechanism 12 is now positioned as shown in Fig. 5, the reset position, and is ready for the timing phase of the cycle.

Upon deenergization of the coil 18 in the embodiment of Figs. 1 and 2, or upon energization of the coil 18 in the embodiment of Fig. 3, the upward force on the operating shaft 36 is removed allowing the shaft 36 to move downward under the bias of the operating spring 98. A partial vacuum is created in the chamber 49 by initial downward movement of the diaphragm 54 which is relieved by air owing slowly into the chamber 49 through the filter 69 and past the needle Valve 68. The rate at which air enters the chamber 49 can be controlled by adjustment of the needle valve 60 to provide time delay periods of a fraction of a second to a minute or more. As the pressure differential between the valve chamber 49 and the exhaust chamber 52 is relieved by the liow of air into the valve chamber 49, the diaphragm 54 and the operating shaft 36 move downward slowly under the bias of the operating spring 98, the downward force being transmitted to the diaphragm 54 through the valve seat 87 which is in Sealed engagement with the bead 85. As the shaft 36 moves downward, it carries, by means of the pin 38 in the grooves 37, the inner end portion of the lever 39 downward. The timing period s completed when the operating shaft 36 has moved the lever 39 far enough to cause the tappet 42 to engage the operator 43 and operate the snap switch 41.

It is to be noted that the pressure in the chamber 49 is greater than atmospheric pressure on the upward or reset stroke until relieved by the cooperative action -between the valve portion 82 and the valve seat 87. Air pressure in the chamber 49 is less than atmospheric pressure on the timing stroke until finally relieved by ow of air past the needle valve 60.

Although the time delay apparatus has been described herein by use of such relative terms as upward and downward, it is to be understood that the apparatus can be operated in any turned position inasmuch as the relative direction of the pull of gravity is of no consequence.

Having thus described my invention, I claim:

1. A time delay apparatus comprising: a housing having a recess, a exible diaphragm closing the open end of said recess to dene a chamber, metering means permitting fluid to enter said chamber at a controlled rate, an exhaust port opening in said diaphragm, a valve normally in engagement with the diaphragm for closing said port openasesinas valve to flex saiddiaphragm from anormal position to Y reduce the volume of said chamber while Yfluid flows rapidly from said chamber throughsaidport opening, said last-named means including means operative upon a predeterminedreduction in said volume toclose said f valve, and means operative to return said diaphragm to its normal position at arate controlledv by the rateof entry of uid into said chamber vthrough, said metering means.

2. A time delay apparatus comprising: a housing having a recess, a flexible diaphragmclosing the open end of said recess to dene a chamber, metering means permitting uid to enter said ychamber at a controlled rate,

an exhaust port opening insaid diaphragm, a valve normally in engagement with thediaphragm for `closing said port opening, actuating means extending through the opening and guided at its opposite ends by the housing and operable to open said valve, yresilient means reacting between thevactuating means and diaphragm for flexing the diaphragm from a normal position to reduce the volume of said chamber while Huid ,flows rapidly vfrom said chamber through said portopenir'lg and thereafter to close said valve, and a spring means operative upon the means extending through the opening to return said diaphragm and Vactuating means to its normal position at a rate controlled by the rate of entry of fluid into said chamber through said metering means.

- 3. A time delay apparatus comprising a housing, a recess insaidhousing, a flexible lmember cooperating with said recess to define a chamber, valve means for admitting a uid to said chamber at a controlled rate, an orifice insaid flexible member, an operating shaft passing through said orifice and guided at its opposite ends by the housing, and a valve seat xed on said shaft for cooperation with said orifice to seal said chamber upon movement of said shaft in one direction and to vent said chamber upon movement of said shaft in the other direction, and resilient means between the shaft and diaphragm for moving the diaphragm in response to movement of the shaft.

4. The time delay apparatus of claim 3 characterized in that said flexible member has a rigid portion supporting said orifice.

5. The time delay apparatus of claim 4 characterized in that said orifice has an annular flange portion for cooperation with said valve seat.

6. The time delay apparatus of claim 5 characterized in that the resilient means normally biases said valve portion against said valve seat.

7. The time delay apparatus of claim 6 characterized in that a second resilient means normally biases said valve shaft in said one direction,

8. A time delay apparatus comprising a pair of recessed housing members juxtaposed to define a chamber, an annular flexible diaphragm clamped at its outer peripheral edge between said housing members to divide said chamber into a pressure chamber and an exhaust chamber, metering means permitting uid to enter said pressure chamber at a controlled rate, an exhaust port in the center of said diaphragm, a valve seat normally closing said port, actuating means extending through the port and guided at its opposite ends by the housing members and operable to move said seat to open said port, means reacting between the actuating means and diaphragm to flex said diaphragm from a normal position to reduce the volume of said pressure chamber upon actuation of the actuating means while fiuid ows rapidly from said chamber through said port into said exhaust chamber and thereafter to close said port by said valve seat, a spring means to return said diaphragm and actuating means to a normal position with said port closed at a rate detervmined by the rate of entry of fluid intosaid pressure chamber through said metering means, electrical contact means, and means rendered operative upon return-ofsaid diaphragm to its normal position to operate said contact means.

9. A pneumatic timer having a valve. housing,.a frustoconical chamber within said housing, anexhaust housing,

a frusto-conical chamber within said exhaust housing, said chambers being juxtaposed and sealed at their peripheri'es, a resilient diaphragm sealed between said housings .for deflection into said chambers selectively, a centralorifice in said diaphragm, an annular raised portion concentric with and adjacent to the periphery of said orilice, yan operating shaft reciprocably supported at its opposi'teend's in said valve housing and in said exhaust housing and passing freelythroughsaid orifice, an annular'valveseaton said shaft having a surfaceY for cooperation with .said annular raised portion, resilient meansreacting between'thefshaft and diaphragm and normallybiasing said .annular raised portion against said valve seat and for ydeiiecting.."said diaphragm into the-chamberof said valve housing upon movement :of `said shaft toward said valve housing, whereby pressure in said valve housingchamber causes said valve seat to separate from said raised portion,

koperating means biasing said shaft away from said valve housing, and uid metering means in said valveV housing for controlling the rate of admission of fluid to saidvalve housing chamber. Y

l0. A time delay apparatus comprising: a `housing having a recess, a exible diaphragm closing theopen end of said recess to deline a chamber, metering means permitting fluid to enter said chamber ata controlled rate,`an exhaust port in said diaphragm, a valve normally closing said port, a reciprocatable plunger operable upon movement of one direction to flex said diaphragm from a normal position to reduce the volume of said chamber, said valve being operative to open upon said exing of said diaphragm and thereby permit fluid to flow rapidly from said chamber while said volume is being reduced andl thereafter operative to close with said volume reduced, said plunger being operable upon movement in the other direction to permitreturn of said diaphragm to its normal position with said valve closed at a rate controlled by the rate of entry of liuid into said chamber through said metering means, a magnetic operator for causing said reciprocation of said plunger, said magnetic operator having a T-shaped laminated iron armature engageable with the plunger, a magnet coil assembly for moving the armature when the coil assembly is energized, said coil assembly having an E-shaped laminated iron pole assembly, a magnet coil encased in a molded covering and having a central bore of rectangular cross section for guiding the movement of the armature assembly, and a pair of side plates secured to the E-shaped core each having: extending portions for positioning the magnet coil on the E-shaped iron pole assembly, an extending portion for securing the magnet coil assembly to a support, a pair of ears for positioning a resilient element for resilently holding the magnet coil on the pole assembly, and a support for a spring for constantly opposing movement of the armature in the rectangular opening in the coil assembly.

l1. An electromagnet assembly comprising in combination: a T-shaped laminated iron armature assembly, an E-shaped laminated iron pole assembly, a pair of outer plates secured to the pole assembly, a molded coil assembly positioned between the arms of the E-shaped pole assembly, said coil assembly having a rectangular opening for receiving the central arm of the core assembly in spaced relation to opposed sides of said central arm of the pole assembly, a U-shaped metal yoke having its arm portions pivotally secured to the armature at the vintersection of the arms and leg of the T-shaped armayoke being movable in the space between the rectangular opening and the central arm of the pole assembly and guided by the inner walls of the opening, ears on the plates of the pole assembly, a U-shaped wire-like spring removably carried by the ears and arranged to resiliently maintain the coil in position on the pole assembly, a second U-shaped spring having its bight portion positioned on the bight portion of the U-shaped yoke and its arm portion positioned by the outer plates of the pole assembly for constantly opposing the movement of the armature by the pole assembly.

12. The combination as recited in claim l1 wherein the plates of the pole assembly embrace a portion of the yoke.

13. The combination as set forth in claim 11 wherein the plates of the pole assembly have ange portions for securing the magnet assembly to a support.

14. The combination as set forth in claim 11 wherein the plates secured to the pole assembly include ears for maintaining the coil against horizontal movement and ears for positioning the U-shaped spring for resiliently resisting vertical movement of the coil on the pole assembly when the magnet assembly is positioned so the armature moves vertically.

15. The combination as recited in claim 11 wherein the second spring opposes the movement of the armature regardless of the relative vertical direction of movement of the armature and pole assembly. Y

16. In a timing apparatus, the combination compris` ing: a housing having a recess therein, a Vflexible diaphragm closing the open end of the recess to define a chamber, metering means permitting fluid to enter the chamber at a controlled rate,l said diaphragm having an exhaust port opening therein, an actuator extending through said opening, valve means carried by the actuator and engageable with the diaphragm for closing the opening, means resiliently connecting the diaphragm and actuator and arranged to ex the diaphragm from a normal position to reduce the volume of the chamber when the actuator is moved in one direction to open the opening to permit uid to flow rapidly from the chamber while the volume of the chamber is being reduced, said means being arranged to move the diaphragm to close the opening when the volume of the chamber is reduced and to maintaining the opening closed while the diaphragm moves the actuator to the normal position at a rate controlled by the metering means.

17. A time delay apparatus in accordance with claim 16 characterized in that electrical contact means are associated with said housingV and means are rendered operative upon returnof said diaphragm to its normal position to operate said contact means.

vreferences Cited in the file of this patent UNITED STATES PATENTS 1,451,328 Desplats Apr. 10, 1923 2,103,378 Oestnaeset al Dec. 28, 1937 2,190,842 Kuhn Feb. 20, 1940 2,206,468 Parkinson July 2, 1940 2,352,765 Bierenfeld et al. July 4, 1944 2,360,856 Doughman et al. Oct. 24, 1944 2,506,225 Kuhn et al. --.May 2, 1950 2,520,212 Jochem Aug. 29, 1950 2,616,010 Scheib Oct. 28, 1952

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