US1797013A - Electromagnetic bell - Google Patents

Description

2 Sheets-Sheet 1 IN VEN TOR .M ATTORNEY J. F. MORAN ELEGTROMAGNETIG BELL Filed Aug. 22, 1923 Jhn loran,

March 17, 1931 vii;

March 17, 1931. J. F. MoRAN y ELECTROMAGNETIC BELL 2 sheets-sheet 2 Filed Aug. 22, 1923 A Q N IN VEN TOR .fa/luz l? mfzzl BY 7/ r/ MATTORNEY i Patented Mar. 17, 1931 PATENT OFFICE JOHN F. MORAN, F JERSEY CITY, NEW JERSEY ELECTROMAGNETIC BELL Application led August 22, 1923. Serial No. 658,668.

My present invention relates primarily to electric signaling apparatus, and more particularly to bells of the solenoid and plunger type such as shown in my application Ser.

5 No. 638,475, tiled May l2, 1913.

Bells ofthis type operate by. powerful distinct strokes on the bell and in said application the design is for single-stroke operation. I have discovered, however, that the same qualities may be advantageously employed for continuously ringing bells sounding so long as the circuit is closed, after the manner of buzzer bells. The preferred structure includes an outlet box, closed by a removable cover casting of unitary construction, which casting constitutes a yoke for the operating solenoid, a guide and support for the solenoid plunger and also a mount for the gong. More specifically, the cover castin has a concavity in the under or concealed si e thereof, within which the solenoid is disposed with its axis vertical in the mounted bell. The plunger is supported upon an integral arm protruding` from the lower end of the cover-yoke member. The gong is removably secured upon the cover-yoke casting, and substantially covers the same, a p0rtion near the rim of the gong being in the path of movement of the upper end of the plunger.

In operation this structure is primarily single stroke but in the form elected for the more specific claims hereof the single strokes are made automatically repeating by an attachment the novel features of which are closely interrelated with several other novel features and combinations, structural and functional, which are characteristic of the single stroke bells of my said application.

The kinds and the many sizes of bells disclosed in my application constitute a new standardized system for commercial installation of all kinds of electric bells.

These bells embody novel features whereby the rear casing which serves as the outlet box or fixture is of relatively small size such that its front is completely closed by the smallest bell which it is proposed to use as standard equipment. In order that such 50 small size outlet box may serve also as a rear casing for a large size alternating or direct current bell the latter is made with its solenoid coil and yoke of a size practically co-extensive with the area of the open face of the outlet box, while the plunger guide and support is pendant any'desired distance below the outlet box, and the whole is covered by the larger size bell or gong which is then employed. This support element for the plunger guide and bell may be formed with two independent bell-securing clamp elements, at different levels with respect to the top of the plunger guide,'so that bells of substantially different size may be em-l ployed, yet both present striking surfaces in exactly the same position with respect to the up-stroke of the plunger.

Specifically considered, my invention involves the use of the same size and model of rear casing or junction box as the support for all sizes of bells and in addition al single size and model of automatic circuit breaker which is capable of use in all sizes of bells.

A novel feature of the circuit breaker is its adaptability and universal application, but its more generic advantages for bells of other models, are the arrangement of circuit breaker elements above and in the path of the striker element, preferably in thecform of a bell crank lever, the work arm of which operates toward the plunger and extends down to a convenient position for operating the circuit breaker. This makes possible the preferable arrangement, which is to have the supports on which the circuit breaking contacts are mounted, extending. parallel lwith the plunger, preferably with the circuit breaking tongue and the bell crank lever covered and protected by a bridge piece which supports the stationary contact. A commercially important feature is making the bridge piece. vibratory tongue and bell crank all from stampings; also having one end of the bridge piece and the tongue secured by the same clamps and the other end of the bridge piece and the bell crank secured by the same pivot member.

In the accompanying drawings in'which is shown one or more of the various possible embodiments oi the several features of this invention,

Fig. 1 is a. trans\-'erse sectional view of one embodiment of bell, with the automatic circuit breaking attachment whereby the hell is adapted for buzzei operation,

Fig. 2 isa rear elevation of the part of the bell structure, separated from the junction box along line 2-2, Fig. 1.

Fig. 3 is a plan View partly in section on the line 3-3. Fig. 2,

Fig. 4 is a view similar to Fig. 1 of a modified form of bell structure; and

Fig. 5 is a sectional view taken along the line 5 5 of Fig. 4.

Referring now to Figs. 1 and 2 of the drawings, I have shown a. bell structure including a. stamped metal outlet box 10, having ay bottom 11, side and end walls 12 and a rim. 13. 'lhe box is provided with the usual depressed slugs 14 which may be punched out, as desired, for insertion of the conduits from the source of current. In the bottom or base of the outlet box is mounted an insulating contact support 15. which may be of molded insulating composition and which is preferably secured to the base as by screws 1G, upstanding shields 17 integral with the support, preventing arcing over between said screws and the contiguous contact 'or terminal strips 18 and 19, and an integral upstanding rib 20 between the two terminal strips, preventing short-eircuiting, creeping or arcing over therebetween. The terminal strips comprise rectangular pieces of lnetal embedded as at 21 within the moldedl composition. each bearing a pair of screws 22, one pair being connected to the source of current (not shown) and the other pair through conductors as at 23 to the solenoid 24 of the bell. Conductors 23 are clamped between a pair of insulating fibre strips 25 and 26, best shown in Fig. 4, provided with corresponding registering notches in their contiguous edges and secured together and against the lower face of casting 28 as by screws 50.

The casting 28 has an integral rectangular frame 29, which serves as a closure for the outlet box removably clamped against the rim 13 thereof by screws 30 and threaded into transverse ledges 31 secured in the outlet box. The castingin the preferred embodiment constitutes a combined magnet yoke and support for the solenoid 24, a carrier support or guide for the solenoid plunger 32 and a mount for the gong 33. The gong, as shown, is preferably removably secured as by a screw 34 upon an 'integral stud 35 in the casting. The casting as shown in the drawings, includes a semi-cylindrical cavi ity 36 in the enclosed side of the casting or cover, within which the solenoid 24 tits with relatively small clearance.

In the embodiment shown, a vertical nsulating tube 37 extends through the axis of the solenoid 24 and is supported in corresponding apertures 38, 39 aud-40 respectively at the upper end of the yoke and at the lower end thereof, in an integral lug 41 depending from the lower edge of frame 28, and below the yoke porton'of the casting. The lower end of the tube 37 is preferably closed as by a plug 42 and is, moreover, secured in position by screw 43 extending transversely therethrough and threaded into the frame 28 of the casting. The plunger 32 is an ordinary soft iron cylindrical rod and is normally cushion ingly supported upon ayieldingporouswad44 resting upon plug 42 in the guide tube. There is a breather hole 46 in plug 42 for in and out breathing of air through the wad, as the plunger 32 reciprocates in guide 37. A resonant metal striking tip 45 has a driving lit in the upper end of the plunger. The rim of the gong 33 extends over the upper or open end of the tube 38 to be struck by said tip.

In operation, upon energizing the solenoid, say by direct current, theplunger 32 is drawn upward in the solenoid 24 and accelerates until it passes what may be termed the center of solenoid attraction, after which it overthrows, that is, travels by acquired momentum the short remaining distance until the tip 45 strikes the bell.' The elastic reaction and gravity combine to cause rebound of the plunger, thus making the blow on the bell a sharp, clean tap.

When the construction is used for single stroke bells, the initial position of the plunger is far down in the solenoid so that the stroke is a long one, and the same situation could be maintained for the continuously ringing bell, but in such case the intervals between taps might be longer than desirable 'because of the length of time required for such long strokes. Moreover, a certain amount of tuning or adjustment of the circuit breaker to the time period of the plunger would be necessary in order to avoid irregularity or missing strokes in the continuous ringing. Consequently, for

the latter purpose, I prefer to make the wad 44 a piece of cork or similar material, operating as a spacer to raise the initial position of the plunger 32 so that the stroke of the plunger is shortened and the plunger works in the strongest part of the solenoid field. This greatly shortens the time required for a complete stroke, thereby increasing the number of strokes per second, and what is more important, making certain that there will be time enough for the plunger to fall deep enough below the center of attraction of the solenoid within the time the circuit is deenergized by the automatic circuit breaker about to be described.

This circuit breaker is shown as an attachment in the form of a bridge assembly which can be applied to any of the varieties of bells shown in my 'prior application referred to,

said circuit breaker, as also the junction box, being preferably of the same size in all cases. It comprises the insulating base-block 26, secured to block 25 by two screws 50 and an insulating clamping block 51 clamped against 26 by said screws 50 and by two other screws 52.

Between blocks 25 and 26 are clamped the metal terminal plate 53, to which terminal 23 is soldered, and the spring tongue 54 which carries the movable contact 55 of the circuit breaker. Said screws also clamp against the outside of the block 51, a thin metal bridge piece 56 which carries the stationary contactl 57 Contact pieces 55 and 57 are preferably of platinum or similar refractory metal. Contact 57 is held in a hollow rivet 58, the inner iiange 59 of which clamps against a sheet metal terminal 60, to which the return wire of the circuit is soldered. This rivet is insulated from 56 by washers 61. The upper end of the bridge piece is U shaped in horizontal section forming ears 64 which fit between lugs 65 which are integral with the cover flange 29 of the bell frame where they are secured by having perforations through which passes pivot bar 66, which is journaled in the lugs 65. The pivot is held from endwise displacement by a U shaped spring clip 67. This end of bridge piece 56 is fixed and the use of the pivot as an anchorage is for convenience.

The movable tongue 54 is retracted to break the circuit by means of a bell, crank lever, which is a piece of light sheet metal provided with an insulating contact piece L69 on the work arm and a fork 70 on the power arm and intermediate bent-up lugs 71 where- 'iy it is freely pivoted on bar 66. Due to the pendant position of the entire lever below the pivot 65 and the greater horizontal distance of the power arm, the normal position of the fork member 70 is resting upon the top of the yoke with crotch of the fork in position to have the striker 45 on plunger 32 project therethrough. The relation of parts is such that during the latter part of the up-stroke of the plunger, preferably the momentum portion of such stroke, the shoulder of the plunger, at the base of the striker 45, engages the forks of the lever, thus forcing the wear piece 69 to the right into engagement with spring tongue 54, thereby flexingA the latter also to the right and breaking the circuit at 55, 57. Preferably, there is slight clearance between the contact piece 69 and the end of the tongue 54, as shown, to make sure of full release of spring 54 when the plunger falls out of engagement with forks 70. Preferably, also, the lever itself is slightly springy so as not to be injured by swift impacts of l the plunger.

momentum part of the up-stroke. This leaves the plunger free to rebound from the bell and to fall by gravity to initial position. The spring 54 of course assists the return of the fork end of the bell crank lever to initial position. The lever is light enough, and the spring 54 is heavy enough, so that there is no tendency to chattering of the contactsl upon closure of the circuit.

Figures 5 and 6 show precisely the same junction box to which the bell frame is fitted as a cover, and precisely the same make and break mechanism applied to the inner surface of said cover, and description thereof would be mere repetition of the previ-ous description. The object of Figures 4 and 5 is t0 show that these features of the invention are readily applicable to any selected model or size of the alternating current bells, as well as to the direct current bells shown in my prior application. As described in my prior application, Fig. 4 has the plunger 32a, square and made up of laminations so as to adapt it for use on alternating current. The gong 33a is of large size and is supported on a depending bracket 48a. The tube 37a of insulating material is preferably provided with a breather hole 100, to prevent dash-pot action of the air which would otherwise betrapped under the plunger. In this case tube 37a being much longer, several pieces of cork 44a are employed to raise the initial position of the plunger to afford a cushion abutment for the down stroke thereof.

It will be understood that in both Figures 1 and 4 the tubes 37, 37a respectively, are longer than they need to be and their use in connection with such extensive'cork filling as may occur. The unfianged portion of the length of bridge piece 56 maybe stilfened by means of a rib 82 if desired.

I claim:

1. In an electro-magnetic bell, a solenoid and a plunger armature therefor, a frame member having a cavity in its rear face for housing said solenoid while forming a magnetic yoke therefor, a bell positioned over the face of said frame member with its rim in the path of said plunger, in combination with a circuit breaker formed of a fixed contact attached to the rear of said frame memframe,

having one end clamped between said blocks 40 ber to bridge said cavity, and a yielding contact for normal engagement therewith, and intermediate means responsive to the working stroke of said plunger in striking said bell for operating said circuit breaker.

2. A magnetic yoke havin a cavity formed in its rear face, a solenoi Within said cavity, an aperture through said yoke, a plunger for said solenoid adapted to traverse said aperture, a bell mounted on the front of said yoke with its rim extending over the axis Aof said solenoid, in combination with a circuit breaker for said solenoid, comprising a bridge assembly. to span said cavity and formed of a stationary Contact, a movable Contact member, and a bell crank lever having one end in the path ot said plunger and the other end in operative relation with said movable contact member. Y

3. The combination specified in claim 2, with the further features that the movable contact ymember is a spring tongue, the stationary contact is carried by an outermost member of the bridge asselnbly which member is spaced apart from but serves as a protective cover for said spring tongue, while the operative end of the bell crank is positioned between said outermost member and said spring tongue.

4. Acsolenoid frame of magnetic material, comprising top and bottom members, a solenoid having its ends magnetically yoked by Way of said members, a plunger for said solenoid, in combination with a circuit breaker for said solenoidoperated by said plunger, comprising an insulating block rigidly secured to the bottom member of the magnetic a'clamping block, a spring tongue and extending approximately parallel with the axis of thesolenoid, a bridge piece having one end clamped to the outer face of said clamping block and extending parallel with said spring tongue, a gong positioned to be struck by said plunger, an operating lever in the path of said plunger, and means for mounting said operatlng lever.

5. A solenoid frame" of magnetic material, comprising top and bottom members, a solenoid havingy its ends magnetically yoked by way of said members, a plunger for said solenoid, in combination with a circuit breaker for said solenoid operated by said plunger, comprising an insulating base block rigidly secured to the bottom member of the magnetic frame, a clamping block, a sprin tongue having one end clainped between said blocks and extending approximately parallel with the axis of the solenoid, a bridge piece having one end clamped to the outer face of said clamping block and extending parallel with said spring tongue, means for securing the other end of said bridge piece to the top member of said frame, a stationary contact on said bridge piece against which contact said spring tongue normally presses, a gong positioned to be operated by said plunger, an operating lever in the path of said plunger, and means for mounting said operating lever.

6. A solenoid frame of magnetic material, comprising top and bottom members embracing the ends of the solenoid and intermediate portions forming a magnetic yoke around the solenoid, in combination with a circuit breaker for'l the solenoid, comprising an insulating base-block rigidly secured 0n the bottom member of the magnetic frame, a clamping block, a spring tongue having one end clamped' between said blocks and extending approximately parallel with the axis of the solenoid; a bridge piece having one end clamped to the outer fac-e of said clamping block and extending parallel with said spring tongue; and a bell crank lever having its work arm mounted between the free end of the tongue and the bridge and the free end of its power arm in the path of the plunger.

Signed at New York city, in the county of New York and State of New York, this 21st day of August, A. D. 1923.

JOHN F. MORAN.

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