US1540063A - Switching mechanism - Google Patents

Description

Patented June 2, 1925.

UNITED STATES PATENT OFFICE.

OSCAR F. FORS'BERG, OF YONKERS, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SWITCHING MECHANISM.

Application filed December 28, 1922. Serial No. 609,378.

To all whom it may concern.

Be it known that I, Osoan F. 'Fonsnnno, a citizen of the United States, residing at Yonkers, in the county of cslchester, State of New York, have invented certain new and useful Improvements in Switching Mechanisn'is, of which the following is a full, clear, concise, and exact'dcscription.

This invention relates to switching apparatus, and particularly to the so-called coordinating switch of the type employed in automatic telephone exchanges.

This invention is particularly applicable to a switching system ofthe type generally disclosed in the British patent to Western lillectric Company, Limited, No. 183,338 of 1923, but it will be apparent to thoseskillcd in the art, that the invention may be applied equally well to other switching systems.

Heretofore and particularly in the switch disclosed in the above mentioned"application, the practice has been' to have a rotata his line bar assigned to each group of incoming lines. Other' rotatable bars are as signed individually to link conductors, and still others to outgoing lines or trunks. The conjoint operation of one of each of these bars effects what is commonly known as a line-link-line connection. The rotatable bars assigned individually to link conductors are generally provided withpermanent- 1y mounted flexible fingers which cooperate with camming surfaces associated with the link bars to effect the aforesaid connections. The use of flexible fingers in a coordinate switch is generally disclosed in British Patent No. 213,437 of 1924, issued to VVester-n Electric Company, Limited. Inasmuch as these flexible fingers are constantly being distorted or tensioncd under the camming action of the line bar it has been found that in some cases these finger members wear out and become inoperative. In other cases the lingers cut grooves in the cams, these grooves holding the wire fingers and preventing their sliding over thecam surfaces.

It is, therefore, an object of this invention to overcome the aforesaid difficulties in a. simple, economical switching structure of the character described above.

This object is accomplished by pivoting the o 'ierating fingers on the horizontal link bars and providing restoring springs therefor which, though acting to restore the pivotal fingers to normal subsequent to their actuation, exert a negligible pressure on the free ends thereof as far as the wear on the camming elements is concerned. The forcgoing result is effected by placing the point at which the spring is made fast to a hori- Zontal bar as close to the pivotal point of its associated operating finger member as possible without nullifying its restoring effeet. The force exerted by the spring on the finger members is a direct function of the finger member and varies from zero when the spring and finger members are parallel, to a maximum when the spring is at right angles to the finger member, assuming, as will be found in practice, that the point at which the spring is made fast to the finger member does not coincide with. the pivotal point of the finger member. It is therefore pparent that there exists a point'along the horizontal bar from which the spring will exert the least force in returning the finger member to its normal position. The pivotal connection is capable of repeated operation for a very great length of time without showing any material signs of wear. Furthermore, the finger is shaped so as to 0011 tact with and slide over the cam surface without the cutting experienced with the wire finger.

The invention will be readily understood from the following description and by reference to the accompanying drawing in which F 1 shows a cross sectional plan view of a part of a coordinate switchen'ibodying the features of this invention; Fig. 2 is a side elevation of the structure shown in Fig. 1 and viewed in the direction of the arrows shown at the dotted line; Fig. 3 is a view of an operating card employed in moving a set of active contacts into engagement with a set of passive contacts; Fig. at shows the particular form. of the operating linger member.

In the followingdescription like numerals designate the san'ie element throughout the several views and particular reference is made to- Fig. 2.

Sets of active contacts 10 are shown partially embedded in a common insulating member 11 suitably held stationary in a switch frame not shown. Partially embedded in the member 11 and individual to each group of active contacts 10 are spring members 12. The spring members 12 are firmly secured to the pins which in turn cooperate with the eyelets 51 in holding a retaining metallic plate member 52 in engagement with the insulating member 11. At the free ends of each set of active contacts, one set of which includes contacts 1 1, and 16, and loosely mounted thereon, is an operating member or card 17 which is adapted to move vertically in a guide by the actuation of an associated spring member 12. The card 17 is provided with a plurality of obliquely disposed apertures 18, 19 and 20 for the admission of the contacts 1%, 15 and 16, respectively, and at its lower end a triangular aperture 21 is provided to admit the spring member 12. The guides for the cards 17 (as seen in Fig. 1) are formed by the superposition of a T shaped insulating member 22 on the fiat rectangular element 23.

Coordinately disposed to the sets of active contacts 10 and interwoven between insulating members 2% are sets of passive contacts, one set comprising contacts -5, 2G and 27 which in a switch of this type are known as link conductors. For each group of link conductor sets or passive cont-act sets there is provided a. horizontal operating bar 28 which has pivotally mounted thereon an extending finger 29, there being one such finger for each set of active contacts 10. The finger member 29 is adapted to be brought into engagement with a corresponding spring member 12 to eti'ect the movement of a card 17 and the subsequent connection between associated sets of active contacts 14:, 15 and 16 and passive contacts 25, 26 and 27.

For each vertical row of active contacts 1 1, 15 and 16 there is provided a vertical operating bar 30 which is provided with extending camming surfaces 31 adapted to cooperate with the free ends of the pivotal tingew 29 and position them in operable relation with the spring member 12. A vertical operating magnet 33 is provided for each vertical operating bar 30 whereas each horizontal bar 28 is actuated by an individual horizontal link magnet 32. The linger members, as shown in Fig. 4, are provided with a substantially spoon shaped end portion, the convex surface thereof acting as a bearing surface between the camming members 31 and the finger members 29.

The following description of a complete cycle of operation of the switch will give a clear understanding of the invention.

Assuming that a subscriber having access to the vertical line magnet 33 initiates a call. The magnet 33 becomes energized and in attracting its armature 35 operates the member 36 which is rigidly mounted on the bar 30, thereby efi'ecting rotation of this bar. The bar 30 in operating moves all of its associated camming surfaces 31. into operable relation with their respective pivotal linger members 29. A horizontal link magnet 32 is then actuated and in attracting its armature 37, operates the member 38 which is rigidly mounted on the horizontal bar 28 (see top of Fig. 2 and right-hand portion of Fig. 1). The bar 28 thereupon rotates and the end of the pivotal linger 29 associated therewith engages a camming surface 31 and is thereupon forced into engagement with a corresponding spring member 12. The

member 29 is provided with staggered pro jections forming a crotch to catch and lift the spring 12. The upward movement of the member 29 is transmitted to the card 17 through the spring member 12. The card 17 in moving upwardly in its guide brings the active contacts 14, 15 and 16 into a wiping engz'igementwith the passive contacts 25, 26 and 27, the wiping efiect being accomplished by virtue of the oblique apertures 18, 19 and 20 in the card 17. The camming action of member 31 causes the element 29 to swing about a point 10 against the action of a restoring spring 41. Upon the completion ot a connection the magnets 32 and 33 become deenergized, the vertical operating member-30 returning to normal under the action of a restoring spring not shown. In like manner a spring 43 returns the horizontal bar 28 to normal subsequent to the deenergization of magnet 32. \Vhen the horizontal bar 28 restores, the pivotal linger 29 disengages itself from the spring member 12 and is then returned to its normal posit-ion by the action of its associated restoring spring ll. The card 17 and its associated set of active contacts then return to normal condition.

It is to be noted that the maintenance of an established connection does not depend upon the continued energization of the vertical magnet 33 but the connection is maintained as long as the horizontal link magnet 32 remains energized. Furthermore, the fingers 29 are held operated free from any mechanical connection with the vertical bars on the cams thereon, so that the vertical bars may be repeatedly operated without disturbing operated contact sets. In this manner the vertical magnet 33 becomes accessible to other line-s in order to cooperate in establishing other connections.

lVhat is claimed is:

1. The combination in a switching mechanism of cooperating active and passive contacts, a flexible element for supporting said active contacts, said active contacts being normally out of engagement with said passive contacts, a pivoted device normally movable in a path ineffective to operate said active contacts, a bar for moving said device, and another bar cooperating with said first bar for causing said device to deviate from its normal path to engage said flexible element to actuate said active contacts.

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2. A switch comprising a passive contact, an active contact, a member for moving said active contact, flexible means for moving said member, cooperating bars, and means associated with said bars for operating said means comprising a pivoted member mounted on one of said bars.

In a switching mechanism, the combination with cooperating operating members of a cam associated with one of said members, an extending finger member associated with said cam, means for holding said finger memberin engagement with said cam, an active contact, and a wire for operatingsaid contact, said wire being adapted to be engaged by said finger member.

4. In a switching mechanism, the combination with cooperating operating. 11161111 bers of a cam associated with one of said members, an extending finger member associated with the other of said members and cooperating with said cam, a spring ar ranged to hold said finger member in engagement with said cam with slight pressure, the pressure increasing negligibly with any slight tension of the spring caused by the camming action of said cam, an active contact, and a spring wire for operating said contact, said wire being adapted to be engaged by the said finger member.

In witness whereof, I hereunto subscribe my name this 26th day of December A. D.

OSCAR F. FORSBERG.

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