US2207506A - Impulse sender - Google Patents

Description

July 9, 1940. x 2,207,506

IMPULSE SENDER Filed Dec. 16, 1937 INVENTOR.

IRVI ATTORNEY.

Patented duty 9, i940 Application December 116, lllti, Serial No. l3l,l2l

4 (Claims.

The present invention relates in general to impulse senders, and more particularly to calling devices for automatic telephone systems orsignalling systems.

An object of the invention is the production of a device of this character that will handle heavy currents without arcing.

Another object is to provide improved contact operating means for impulse senders.

A further object of the invention is toproduce an improved device of this character that may be used in locations that are hazardous because of the presence of explosive gases that may be ignited by an electric arc.

Another object is to operate the contacts of an electrical make and break device by d rect magnetic action Without intermediate ical linkage.

A feature of the invention is contact spring arrangement completely sealed in an evacuated glass tube, the springs being operated by the turning of a permanent magnet.

A further feature is the elimination of wear, due to friction, on the contact spring and the cam co-operating with it, by operating the contact without physical connection with the contact operating means.

When direct current impulses are transmitted over a line containing inductance, an inductive discharge inevitably results from the opening of the circuit, and is manifested at the opened contacts by the presence of a spark. In hazardous locations that may be exposed to the presence of explosive gases, such as in a dirigible, in a mine, or in similar locations, the producton of a spark is highly undesirable. In the instant invention the production of a sparkdue to inductive discharge is inhibited by the fact that the impulsing contacts are in a vacuum. Furthermore, any spark that may develop will have no efiect since the point of sparking is effectively insulated from the atmosphere by the surrounding vacuum. Another advantage of such construction is in the practical elimination of inductive interference to neighboring radio receivers.

The improved contact arrangement and operating means has been applied to a calling device of the type shown in Obergfell Patent No. 1,642,822, patented September 1927 The invention is illustrated in the accompanying drawing comprising Figs. 1 to 5, in which:

Fig. 1 is a rear view of the calling device of the above-mentioned patent modified to include the features of the instant invention;

Fig. 2 is a side view of the complete device;

(iCi. me es) 3 is an enlarged side view oi the evacuated glass tube containing a pair of impulse springs;

4 is an end section of Fig. 3, taken along the line i d;

Fig. 5 is a side view of the mounting detail or the tube.

The calling device of the instant invention is substantially identical with that shown in the hereinbefore mentioned patent, modified to the extent that the impulse cam has been replaced by a iJ-shaped permanent magnet and the exposed impulse springs have been replaced by a pair of impulse springs enclosed within a hererratically sealed glass tube.

Referring now to Figs. 3 and 4, it will be seen that the impulse sending springs 23 and 2d are enclosed within an evacuated glass cylinder 29, the exposed portions of the springs serving as terminals for the connection of Wires. Spring 23 atits inner end has welded to it a short length of Wire 22 to form a contact. Spring 26 at its inner end bears an i..-shaped length of wire 2i forming a contact to cooperate with contact 22. In addition spring 2d has welded to its underside, a length of magnetic material 25 which is approximately the length of the magnet iii Incas-- ured from the outer sides of the pole faces. The vacuum contact unit is so made that the contacts 2i and 22 are normally held apart by the tension of springs 23 and 2d.

Referring now to Fig. 2v the vacuum contact unit is clamped to bracket it, which is in turn adjustably mounted on an L-shaped bracket it, by means of screws it. This adjustment is provided to vary the distance between the springs and the permanent magnet in order to provide for various impulse ratios. In its normal position, the permanent magnet i2 is mounted on the driving spindle of the calling device by means of nuts ii and It, in a direction parallel to the longitudinal axis of the magnetic element 25. In this position, spring Ed is attracted to the magnet l2 and the contacts are closed, corresponding to the usual construction of such calling devices. When the finger hole plate I9 is turned from its normal position and allowed to restore, to send a single impulse, the magnet l2 starts to turn about its axis, thus widening the air gap between the pole faces and the magnet element 25. Before reaching a point at right angles to its normal position the magnet flux flowing in the circuit is decreased, due to the increased air gap and consequent increase in reluctance, to such a degree that spring 24 is permitted by its own spring tension to restore to a iii normal position, with contacts 25 and 22 separated.

The magnetic attraction, of course, is at a minimum when the magnet is at right angles to the length of the spring and varies gradually in degree in proportion to the angular displace-. ment of the magnet. As the magnet passes its point of minimum attraction and continues to its normal point of rest the magnetic attraction increases gradually until it is suficient to overcome the tension of spring 21% and again close contacts 2! and 22 to terminate the impulse.

It will be seen, therefore, that for each onehalf revolution of the magnet, one impulse is produced, and in this respect is identical in operation with the calling device of the patent previously referred to.

As mentioned previously, thevacuum tube is adjustably mounted on bracket a, this adjustment being made possible by the slotted holes 58 in bracket It. In this way it is possible to vary the distance between the magnet and the elements of the tube to provide the most desirable time ratio between make and break of the contacts.

Although the invention has been described with reference to a specific structure, a number of modifications will at once suggest themselves. For instance, the magnet may be turned at right angles to the position shown, in which case the contacts will remain normally open, being closed intermittently instead of being normally closed, then opened intermittently. Again, the contacts 25 and 22 may be disposed adjacent the lower side of spring 23 instead of the upper side as shown. This construction also will produce closed circuit pulses but without the necessity of turning the magnet at right angles.

The vacuum tube has been described as being evacuated. Alternatively, the tube may, instead of being evacuated, be filled with an inert fluid.

What is claimed is:

1. In an impulse sending device, a manually operable dial, a magnet, means including a gear train for rotating the magnet a number of revolutions dependent upon the angular lacement of the dial. impulse springs, means for so mountaao'aaoe ing said springs with respect to the path of said magnet that said springs are operated by magnetic influence during a portion of each revolution of the magnet, said last means permitting the mounting of said springs with respect to the path of the magnet to be varied to proportion the amount of each revolution of said magnet during which said springs are influenced.

2. In an impulse sending device, a pair of contacts within a hermetically sealed vessel, a magnetic element forming a part of one of said contacts, a U shaped magnet having pole faces and pivoted at a point midway between said pole faces, said pole faces adapted to be positioned along the longitudinal axis of said element or perpendicular to the longitudinal axis thereof in dependence upon the position of the magnet, both of said pole faces lying at all times in a plane parallel and adjacent to one side of said element, a manually operable member, and means responsive to a single manual operation of said member for moving said magnet and said pole faces alternately from one oi said positions to the other for operating said contacts, the number of said alternations dependent upon said single manual oper- 2 ation of said member.

3. In a device as claimed in claim 2, wherein said contacts and said vessel comprise a unitary structure, means for varying the distance between said structure and said pole faces.

4. in a circuit controlling device, a rotating magnet, said magnet having a plurality of pole faces all lying in the same plane and remaining in said plane continuously during the rotation of the magnet, circuit controlling springs, a magnetic member associated with said springs, said member normally at rest adjacent to said plane and operated by the magnet during a portion of each revolution thereof thereby 'to actuate said springs, and means for varying the positionoccupied by said member when at rest with respect to said plane thereby to proportion the amount of each revolution during which said magnet shall operate said member. v

IRVIN W. COX.'

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