US1464478A - Retarding device for time-limit relays - Google Patents

Description

T. T. GREENWOOD RETARDING DEVICE FOR TIME LIMIT RELAYS Filed 511116.17, 1918 Patented Aug.. 7, 1923.

uniransrarss TnLMn T. GREENWOOD, or EAST TEMPLETON, MASSACHUSETTS, ASSIGNOP. To s. n. eONoT, JP... or BnooxLrNn, MASSACHUSETTS.

RETARDIMNG DEVICE FOR TIME-LIMIT RELAYS.

Application filed June 17, 1918.

To all whom t may concern: y Y i Be it known that I, TALMA T. GREENWOOD, a citizen of the United States, residing at East Templeton, in the county of Worcester and State of Massachusetts, have invented an improvement in Retarding Devices for Time-Limit Relays, of which the following is a speciiication.

My invention relates to time limit relays adapted for the protection and control of electric circuits and apparatus connected thereto.

The invention has particular reference to time limit relays having a flexible or yielding diaphragm which is actuated by the plunger of a solenoid to force air through an orifice, the rate of flow of air through said orifice determining the time element of the relay.

The object of my invention is in the provision of a relay which is simple and inexpensive in design and construction, and which is positive and reliable in, operation.

Fig. 1 is a sectional elevation of a relay embodyingrv my invention.

Fig. 2 is a side elevation of the relay.

F ig. 3 is a plan view of the relay.

Fig. l is a modified form of diaphragm.

Figs. 5 and 6 are modified forms of diaphragm engaging members.

ills here shown the relay comprises the solenoid or coil 10 which is arranged within the casing 12 formed of magnetic material, and which has a top pole piece 13 extended within said coil vand magnetically connected with said casing 12.

The solenoid or coil 10 is Wound upon, or is provided with, a central tube 14, ofbrass or other non-magnetic material in which is slidably arranged a similar tube 15. fr core or plunger 16 is disposed within said tube 15 and is adjustable therein to vary the current value at which the solenoid will operate by means of a'screw threaded end cap 1 7 which fits in similar threads of the tube 15. A rod 118 is secured in the upper end of said tube 15 and slidably extended through the top pole piece 13 of the solenoid and serves as means whereby a movement of the core is transmitted to the time element of the relay.

Serial No. 240,385.

The time element includes a cup shaped pot 19 which is disposed above the solenoid and supported in such position, by the standard 20., A flexible or yielding diaphragm 21, which forms an object of my invention, is secured over the cup shaped end of said pot 19, in any suitable manner, such for instance, as by means of thelhelical springs 22. A diaphragm-engaging mem-r ber 23, suitably curved to conform to the cupped end of the pot 19 is secured to the .centre of said diaphragm 21, and when moved upward by the movable element of the solenoid serves to force said diaphragm into said cup shaped opening. The diaphragm-engaging member 23 is secured at substantially its central portion, to a downwardly extending stein 241 which has a central recess 25 in which the rod 1S of the movable element of the solenoid is slidably arranged.

Said rod 18 is provided with a flange 26 pinned or otherwise secured thereto between which and the bottom of a recessed opening 27 in said stem a spring 28 is arranged and through which movement of the movable element of the solenoid is transmitted to the diaghragm-engaging member. This arrangement of yielding connection of the movable element of the relay and the kdiaphragm-engaging member of the time element provides means whereby a substantial uniform pressure may be exerted against the diaphragm of the time element regardless of the varying energir/iation of the solenoid with differing current values.

Upwardly extended spring contact members 29 are secured tosaid stem 24: which are adapted in the extreme operated position of the diaphragm-engaging member to malte contact with suitable Spring contact members 80 upwardly extended from and secured to an insulating base 31, and which are adapted to be connected to the circuit to be controlled.

lt is desirable that after the diaphragmengaging member has moved upward to force the diaphragm into the cup shaped opening in the pot 19 and to force the air from between said pot and the diaphragm, as will be hereinafter described, that means lbe provided, after the Contact members have been made to control the circuit connected thereto, to rapidly admit air to the space between said poty and diaphragm and permit the rapid return of the relay to its normal condition'in readiness fora subsequent operation.

For this purpose a check or automatic in-l let valve 32 is arranged in the pot 19 and serves, during the return of the diaphragm 2l to its normal condition, to rapidly admit through the leak valve determining'the time element.

Instead of providing a fluid tight diaphragm and a leak valve, I prefer to omit the leak valve'and to form a yielding diaphragm of a suitable pervious material through which the air vmay flow at a suitable rate when said diaphragm is moved upward into the cup shaped opening of the pot 19.

The pervious diaphragm may be of any suitable material which will satisfactorily answer the purpose. It may be for instance, of a material, as suitably compressed felt, which is uniformly porous as shown in Fig. l, or it may be of a material as gold beartes skin which isimpervioiis to air and which lio khas a plurality of mechanically formed air openings or relatively minute pores or perforations L.l0 therethrough, such for instance as shown in Fig. ll.. rlliese openings or perforations may be arranged in any suitable or desi red pattern.

In connection with a porous or pervioiis diaphragm, I prefer to use a diaphragm-engaging member having a corrugated diaphragm contactino` surface or having a plurality of perforations therethrough.

In Figsi'l and 2, I have shown a substantially uniformly porous diaphragm and a diaphragm-engaging member which has av smooth diaphragm contacting surface. llith such an arrangement it is seen thatas the diaphragm-engaging member, is moved upward, it engages more and more of the surface of the diaphragm and so progressively closes the pores of the diaphragm. and thereby progressively restricts the flow of air therethrough and consequentlyA the time 'element progressively increases.

In Fig. 5, I have shown a diaphragm-engaging member 23 provided with a plurality 0f corrugations. The depth of these oorrugations is arranged to be such that the dia-l phragm does not fill. the corugations and the actual contacting surfaces of the corrugations of the diaphragm is'arranged to be coinparatively small so that as the diaphragmengaging member is moved upward into increasing contact with the diaphragm the flow 0f air from that portion of the diaphragm in contact with the Vdiaphragm-eiigagiiig member is not appreciably retarded.

Inv Fig. 6, I have shown a diaphragm-engaging member 23 provided with a plurality of perforations l5 through which air is adapted to pass from that portion of the diaphragm in contact with the diaphragmengaging member.l

It is evident that many modifications of vdiaphragins maybe employed through which the air is adapted to be forced in the upward movement' of the diaphragm and many forms of diaphragm-engagingl members may be also employed in conjunction.`

tact with said diaphragm for its actuation i i having fluid passages therein for the flow of fluid from said reservoir. l

2. A retardingdevice'comprising a fluid reservoir a fluid permeable diaphragm forining a wall Aof said reservoir, vand a diaphragm-engaging member adapted to contactwitli said diaphragm for its actuation formed with corugations therein for the flow'of fluid from said reservoir. 'Y

3. A retardation device comprising` a fluid reservoir.y a flexible fluid-permeable diaphragm forming` a wall of said reservoir,

and a diaphragm-engaging member engageable with said diaphragm for its actuation. In testimony whereof. I have signed my name to this specification, in the presence of the subscribingwitness.

` TALMA T. GREENWOOD. llVitness:

II. B. Davis.

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