US2075499A - Switching device - Google Patents

Description

March so, '1937. p. E. BUCH ET AL 2,075,499

SWITCHING DEVICE Filed Jam 11, 1956 9 l8 F/G.3 I725 '24 2/3/ 23 22.27 3029 l/ I/ ll/ R EBUCH AAflAA/SEN A T TORNE' V Patented Mar; 30, 1937- UNITED STATES PATENT. OFFICE swrrcnmc DEVICE Application January 11 1936, Serial No. 58,652

1 Claim.

This invention relates to electromagnetically operated switching devices in which contacts are operated by the movement of an armature in response to the energization of a magnet.

In swtiching devices of this type and in particular those used in certain telephone circuits, for example, where the motor magnet is energized by an alternating current source, the core of the magnet, as is well known, isfltted with a copper plate which is provided to maintain the magnet .energized during the reverse cycle of the current. In such magnets, however, it has been found that even the accurate dimensioning of such a plate with respect to the frequency used did not prevent chattering of the armature, and

that of the contacts actuatedthereby, and that this condition was the cause of objectionable noise or clicks generated inthe telephone talking circuit in which these relay contacts form a part.

The object of the invention is to provide a which is free of such objections.

In accordance with this invention, an electrospect to the energizing force of the magnet on its armature.

Other novel features and advantages of the invention will appear from the following description and by the claim appended thereto, reference 40 being had to the accompanying drawing, in which:

Fig. 1 is a front view of a magnet embodying the toggle mechanism of the invention;

Fig. 2 is a side view thereof;

Fig. 3 is an enlarged top view showing the 45 magnet armature in its retracted position;

Fig. 4 is another enlarged top view showing the magnet armature in its operated position;

Fig. 5 is a front view of a magnet showing a modification of the invention, the magnet arma- 50 ture being shown in its retracted position; and

Fig. 6 is a partial view of the modified magnet showing the armature in its operated position.

The alternating current magnet vto which the invention is particularly well adapted for use 55 generally consists of a core 8 fitted at both ends switching device of the type above referred to with spoolheads l0 and H and awinding l2. The core 9 extends beyond the spoolheads I0 and H and is formed at its rear end with lateral projections for mounting an armature IS in attractable relation with the prongs Pi and P2 formed at the other end of the core, as shown in Figs. 3 and 4, the armature l3 being attached to the rear end of core 9 by two similar ribbon springs l5 shown in Figs, 1 and 2 which permit the pivotal v movement of the armature at this point. A cop- 10 per plate i6 is secured on spoolhead H at the front end of the magnet and engages the prongs PI and P2 of the core 9, the copper plate l6 being provided for holding the relay energized during the reverse or negative cycle of .the current and 15 on' this plate are mounted a number of screws, such as H, bearing on the camming portions of springs, such as 20, secured to the arms of armature 13 for returning this armature to its retracted position upon each deenergization of the magnet.

0n the copper plate i6 is secured, as by rivets 2| and 22, an angle-shaped bracket 23 having an upright extending lug portion 24 provided for receiving a screw 25 which is axially movable therein by the turning movement of nut l8, the screw 25 being held against turning movement upon the turning of nut 18 by an arm Xi extending against the vertical portion of bracket 23, as shown in Figs. 2 and 3. Bracket 23 is formed with a portion 26 provided for mounting, as on a knife-edge pivot, a link member 21, having a slot 26 shown in Fig. 1 for engaging the constricted portion of a nut 29 threadedly engaging a screw 30 carried by armature 13, the link member 21 being held against the bracket portion 26 by a spring 3| having one of its ends hooked to the screw 25 andits other end to the link 21, as shown in Figs. 1, 3 and 4, the line of maximum tension of spring 3i occurring where the longitudinal axis of the link 21 forms a straight line with respect to the attaching point of spring 3| on the screw 25, its pivotal point on the bracket portion 26 and its attaching point with this link, and any deviation of link 21 from such a line will cause the spring 3| to move the armature I 3 either toward the core 9 of the magnet or away therefrom, as the case may be, for a purpose that will be hereinafter described in detail.

The nut screw 29 may be moved on the screw 30 in position wherein the link 21 will be moved to impart to the armature IS the desired pressure toward the core in relation to the adjustment of the screw l1 bearing on the camming portion of retractile spring 20.

In the modification of the invention shown in Figs. and 6, an arm 40 is secured on the ends of cores 4| and 42 by screws 43 and 44, the core 4| at this end being provided with a lug 45 for securing one end of a ribbon spring 46 which serves as a pivot for the armature 41.

The arm 40 is provided at its free end with a lug 48 laterally extending therefrom for mounting a screw 49, the end of the screw having a conical recess for receiving the pointed end of a compression spring 50, and the other end of this spring engages a similar recess in the end of armature 41, the line of maximum tension of spring 50 occurring when the pivotal point of armature 41, the axis of screw 49, and the engaging point of spring 50 with the armature 41 are in straight line relation and any deviation of the armature from such a line will cause the spring 5|] to force this armature either toward the end of core 42 or toward the screw 5| which limits the movement of armature 41 away from the core 42, the screw 5| being adjustably mounted on arm 52 which is, in turn, secured to the core 4|.

In a typical example of operation of the device shown in Figs. 1, 2, 3 and 4, the energization of the magnet and the consequent attraction of armature l3 from the position shown in Fig. 3 is efiective to move the link 21 for tensioning the spring 3| to a maximum which occurs when the link 21 forms a straight line with respect to its attaching points with the screw 25, its pivot and its connecting point with the other end of spring 3|. However, upon the continued movement of the armature and, therefore, the passing of link 21 beyond such a line, the link 21 is moved in the position shown in Fig. 4 with the armature l3 engaging the prongs PI and P2 of the magnet, the tension of spring 3| being thus effective to assist the magnetic flux as afforded by the copper plate I B in holdingthe armature in its operated position during the reverse or negative cycle of the current and thereby preventing chattering of the armature and that of the contacts actuated thereby under the tension of the retractile spring 20 which is adjusted to overcome the tension of spring 3| uponthe complete deenergization of the relay. The change from a positive to a negative force on the armature can be adjusted to be suflicient to overlap the margin of pull which exists between the peak and the minimum values of flux produced by the alternating current so that the relay once operated will remain so until the current applied has been appreciably reduced.

In an example of operation of the modification shown in Figs. 5 and 6, the compression spring 50 normally holds the armature in its retracted position, as shown in Fig. 5, and in engaged relation with the adjustable screw 5|. Upon the movement of armature 41 when electromagnet I2 is energized, the spring 50 is compressed up to a point where the armature is in line with respect to its pivotal point and the axis of screw 49. The

passing of armature 41 beyond such a line in en-.

gaged relation with the ends of the cores 4| and 42, the tension of spring 50 as adjusted by the screw 49 is effective to assist the magnetic flux as afiorded by the copper plate IE to hold the armature 41 in engaged relation with the core during the reverse or negative cycle of the current, thus preventing the chattering of the armature 41 and the contact actuated thereby against the tension of retractile spring 60 which is adjusted by the turning movement of nut 6| on screw 62 carried by the magnet armature.

From the foregoing, it is apparent that we have provided a relay, the performance of which is stabilized and certain of its operating characteristics modified by an auxiliary spring. This relay thus provides for a decrease in the holding current value as compared to the operating current value; for slower operating or slower releasing without employing non-commercial contact spring adjustments; for increased contact pressures. Also, when used in direct current relays which are normally held operated over considerable periods of time, the auxiliary spring by serving to reduce the holding force required on the armature permits of the use of an auxiliary contact to insert resistance in series with the winding after the relay has been operated, thereby reducing current drain, or, in relays having heavy spring pile-ups the auxiliary spring can be employed to partially balance the build-up force of the contact spring pile-up which develops as the relay armature is operated and thus, without lessening contact pressures, permit economies in winding design or decrease in the value of the required holding as well as operating current, andin slow operate and release relays, the auxiliary spring by balancing part of the restoring force of the contact springs may permit larger numbers of springs on a relay for a given slow characteristic or of increasing the time of release or operation.

It is to be understood that the auxiliary spring may be used to either pass from one side to the other of its line of. unstable equilibrium, to move from one side only to its approximate line of equilibrium, or to move from its line of equilibrium to one side of this line, and that any of such arrangements fall within the scope of the invention.

What is claimed is:

In a switching device for use in a circuit energized by an alternating current source, a magnet having a core, a copper plate mounted at one end of said core, an armature for said magnet, a toggle mechanism operatively connected to said armature for assisting the magnetic flux furnished by said copper plate upon the reverse cycle of the current for holding the armature against said core, a retractile spring for said armature, and contact members operated by said armature.

PETER E. BUCH. ARNOLD A. HANSEN.

Images