US1918473A - Polarized relay - Google Patents

Description

W. H. HOPPE POLARIZED RELAY July 18, 1933.

Filed Oct. 16. 1950 mm m ATTORNEY Patented July 18, 1933 lUNl-TED STATES PATENT OFFICE WALTER H. norm, or nocnnsrna, new YORK, essienon TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK POLARIZED RELAY Application filed October 16, 1930. Serial No. 439,091.

This invention relates to polarized relays and more particularly to the polarized type ofrelays used in a centralized traffic controlling system for railroads or which are often referred to as telephone relays.

The usual type of polarized three position telephone relays employs two operating electro-magnets so arranged as to attract an armature to one or the other according to the direction of current flowing in the electromagnet coils. This is accomplished by arranging the electro-magnets so that the flux emanating from their cores is related to a flux from a permanent magnet in a way to unbalance the fiuX passage on one side or the other'of the armature axis according to the current flow,'thereby causing a corresponding motion of the armature; The use of such a relay in a, centralized traflic controlling system on a railroad necessitates that its size be kept as small as possible because of the large number required and the comparatively small space in which it is necessary for I them ,to'be grouped. The usual type of polarized relay can not bev conveniently grouped in such a system because of the large dimensions made necessary by its two electro-magnetsand consequently is not particularly adapted to such a system. A

In View of these facts, it is proposed in accordance" with thisinvention to provide a small dimension polarized relay made possible by the use ofonly one electro-magnet which will be simple and dependable in its operation. 1

Other objects, purposes and characteristic features of the invention will appear as the description thereof progresses, during which references will bemade to the accompanying drawing which shows the invention in a wholly diagrammatic Way to make it easily understood, rather than to illustrate the particular construction preferably employed in practice, and in which Fig; 1 shows a top viewof the invention.

Fig.2 shows a side view of the invention. Fig 3 is 'a perspective and diagrammatic View of the invention with the armature shown away from its normal position to facilitate tracing the various paths of flux.

The relay as shown 011 the accompanying drawing includes a soft iron core 1 with a threaded mounting extension 1 upon Which a carrier member 2 is fastened by nut 3. The core 1 carries a coil 4 which is to be energized by a changing polarity of direct current to thereby form an electro-magnet. Equally spaced from core 1 on the carrier member 2 are mounted permanent magnets 5 and 6 by clamps 7 and S-to thus extend parallel to core 1 and wit-h their free ends of opposite polarity. Also mounted on the extension 1 of core 1 is a U-shaped strip 9 also fastened at its center point. by nut 3 and and with its ends extending parallel to and equally spaced from the core 1 but interspaced in quadratic relation to the permanent magnets 5 and 6. 1

The movable members of the relay comprise an armature 10 pivoted centrally with I respect to core 1 with its axis 11 in line with the ends of the U-shaped member 9 and suitably supported by means not shown on the drawing. This permits a motion thereabout either against permanent magnet 5 or permanent magnet 6, and thereturn of armature 10 is assured by means of a biasing spring 12 acting upon an armature arm 10 The circuit changing means consistof insulated contact arms 13 and 14: adapted to engage either stationary contact 15 or 16 respectively, all of which is shown diagrammatically to simplify the drawing.

The path of the flux from the permanent magnets 5 and 6 when the coil 4 is deenergized can be considered to flow as follows :the flux produced by permanent magnet 5 flows out of its north pole N, through an air gap to armature 10, through armature 10, through an air gap to the south pole S of permanent magnet 6. where it is strengthened bythe flux producedby it and flows out its opposite end, through the carrier member 2 back to the opposite end of permanent magnet 5. This path is'of lower reluctance than any other path because the flux values of the permanent magnets are additive, and the magnetic force produced acts onthe armature 10 in such a way that it is equally distributed on each side of its axis 11 thereby producing no turning effort and the armature 10 remains in its mechanicallybiased neutral position.

The flux in the center core 1 and the legs of the U-shaped member 9 under the above deenergized condition will be the resultant value of the magnetic forces of the two permanent magnets. Considering that the strength of the two permanent magnets is substantially equal, and that the structure is symmetrical, the flux in the center coreand the leakage strips is of a negligible value, because the flux tending to flow in these parts from the north. pole N of permanent magnet 5 is equally opposed by the flux tending to flow in these parts from the north pole of permanent magnet 6.

. If now it isvconsidered that the coil 4 is energized with a certain direction of current so that the free end of the core 1 is made a north pole, the flux emanating therefrom finds a path of higher permeance through the right hand half of the armature 10 to'the permanent magnet 6 because the direction is such that it is additive to the permanent magnet flux in this half but is bucking the permanent magnet flux in the left hand half. This causes a greater amount of flux to flow in the right hand half which unbalances the mag netic force about the axis 11 and the armature 10 is rotated against the permanent magnet 6 which engages contact arm 13 with stationary contact 15'. I l

A current applied to the coil 4 in a direction opposite to the direction just assumed makes the free end of the core 1 a south pole and it is obvious that the armature willbe attracted to permanent magnet 5 due to a similar unbalancing of magnetic forces about the axis 11, which results in'contact arm 14 engaging stationary contactlfi.

The purpose of the 'U-shaped member 9 is to provide a path for the permanent magnet flux which is opposed by the flux from core 1 produced during the energization of coil 4,

thus obviating the tendency for the opposed permanent magnet to become demagnetized. For example, when the core 1 is made a north pole at its free end, the flux emanating therefrom opposesthenormal flux flowing from permanent magnet 5 in the left hand half of armature 10, but the flux inpermanent magnet 5 isnot greatly reduced because it finds an auxiliary return'path through the legs of the U-s'haped member 9 toits south pole. It

should be noted that the legs of the U-shaped member 9 will likewise carry the leakage flux of the permanent magnet 6 when the energy on coil 4 is reversed, bat ina reverse direction to the previously assumed-case.

It is found in practice that two straight bar permanent magnets can be manufactured with very slight variations in magnetic strength or reluctance, but if such variation is discovered, itseffeot on the magnetic circuit can be compensated for by adjusting the permanent magnets in their retaining clamps 7 and 8. It is possible to employ a single U-shap-ed permanent magnet in the place of the two bar magnets, but it is found difficult to evenly magnetize such a magnet throughout its length. Such uneven magnetism, with the core 1 evenly spaced between 5 and 6, causes a, circulating path of flux from the stronger portion through the center core 1 and also the legs of the U-shaped member 9 and the corresponding half of the armature 10, which imbalances the magnetic force on the armature as well as unbalacing the required operating energy.

Having shown and described one embodiment of the present invention, it is desired to be understood that this form is selected to facilitate in the disclosure thereof rather than to limit the number of forms which it may assume; and, it is to'be further understood that various modifications and alterations maybe applied to the form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention, or the idea of means underlyin the same.

Having thus described my invention, what I claim is:

1. A polarized relay comprising a carrier member of magnetic material, an electromagnet including a soft iron core with one end rigidlyv fastened to said carrier'member, two straight permanent magnets with respectively alternate poles fastened to said carrier member and located in a common plane with said electro-magnet equally spaced therefrom, two strips of magnetic material with one end of each fastened to said carrier member and extending parallel to said electr c-magnet, equally spaced therefrom, and located in a plane which is substantially at right angles to the aforesaid common plane of the permanent magnets, an armature with its axis located in said plane of the magnetic strips and electromagnet and adapted to move there-about into contact with either of the free ends of said permanent magnets, said armature being biased to a neutral position, and havin suitable circuit changing means attache thereto. i

2. A polarized relay comprising a carrier member of magnetic material, an electromagnet including a soft iron core with one end rigidly fastened to said carrier member, two permanent magnets with opposite poles adjustably clamped to said carrier member equidistant from and parallel to said electromagnet core, a U-shaped member fastened at its mid point to said carrier member at the point of connection with said electromagnet core and its sides extending parallel thereto equally spaced therefrom and substantially at right angles to said permanent magnets, an armature with an axis Sllibfififilh tially at right angles to the plane of said permanent magnets and movable to make contact with either of the free ends thereof, and means acting on said armature to bias it to its neutral position.

3. A polarized relay comprising a carrier member holding two permanent magnets with opposite poles adjustably clamped thereto and extending in spaced parallel relationship substantially at right angles to said carrier member thereby forming a U- shaped assembly, an integral member shaped similarly to said U-shaped assembly, an electro-magnet with an extending soft iron core, the extending portion of said electro-magnet core passing through the central part of said U-shaped assembly and the central part of said U-shaped integral member, a nut threaded on the extending portion of said electromagnet core thereby clamping the two aforesaid U-shaped members to the core in a fixed quadrature relation to each other, and an armature pivoted. and biased in central relationship to the free end of said electro-magnet core and arranged to operate contacts by its movement against either of the two permanent magnets in accordance with the polarity of the electro-magnet energization.

4. A relay including two permanent magnets, an electro-magnet, a carrier member for said permanent magnets and said electromagnet, two elongated strips of magnetic material fastened to said carrier member parallel to and symmetrically disposed relatively to said permanent magnets, and an armature biased to a neutral position and adapted to move toward either of said permanent magnets according to the polarity of said electro-magnet energization.

5. A polarized relay comprising an electromagnet with a soft iron core having a threaded mounting extension, a carrier member of magnetic material fastened at its central point to the threaded extension of said core adjacent said electro-magnet, two elongated permanent magnets adjustably clamped to said carrier member at their extreme opposite poles and extending in equally spaced and parallel relationship to said electro-magnet, a movable member biased to a neutral position and adapted to move against either of said permanent magnets according to the polarity of the electro-magnet energization,

and a leakage flux path partially encircling said electro-magnet which includes two mag netic strips interspaced in quadrature parallel relation to said permanent magnet.

WALTER H. HOPPE.

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