US2381978A - Impulse transmitter - Google Patents

Description

Aug. 14, 1945. R. c. MATHES IMPULSE TRANSMITTER- Filed Aug. 5, 1943 2 Sheets-Sheet 1 M w y lNl fNTOR RC. MA THES Q lt-d.

A TTORNEY Patented Aug. l4, 1945 UNlTED STA" TRANSMETTER Application August 5, 1943, Serial No. 497,538

d Glaims.

This invention relatesto impulse transmitting devices and more particularly to telephone call transmitters of the key-operated type.

It is the object of this invention to provide an impulse transmitter of the key-operated type which embodies characteristics that are particu-- larly desirable from the-users standpoint and which functions to transmit series of correctly timed impulses without imposing any undue reautomatically to transmit the predetermined number of impulses at a predetermined desirable speed or frequency independently of any control by the manually operable means. More particularly, the transmitter of this invention embodies an impulse counter comprising a plurality of manually displaceable resilient balls which may be selectively divided into groups containing one to ten balls to .correspondingly predetermine the number of impulses to be transmitted, and electromagnetically controlled, mechanically tuned means for individually restoring the balls of a selectively displaced group of balls and for simultaneously operating a set of pulsing contacts once for each ball individually restored.

In the particular embodiment of the invention disclosed in the drawings a row of ten balls is normally confined between two oppositely disposed poles of a permanent magnet. The balls are arranged in consecutive contiguity in such a manner that the last ball of the row abuts one of the permanent magnet poles and the first ball of the row is spaced from the other permanent magnet pole. A group of ten individually manually operable keys is arranged in superposed relation to the row of balls, each key being so contoured as to function, when depressed, as a camming device for displacing one or more balls from their normal positions and for moving the said balls in such a direction that the first ball of the selectively displaced group of balls contacts the other permanent magnet pole. The

'number of balls thus displaced is determined by the particular keyactuated and predetermines the number of impulses to be transmitted. An

electromagnetic interrupter is rendered eiiective at a particular stage in the operation of a key and functions through a mechanically tuned striker or hammer to repeatedly strike the permanent magnet pole against which the selected group of balls has been moved to cause one ball of the selected group of balls to be returned to its normal position for each impact of the striker against the permanent magnet pole. The striker functions simultaneously to operate a set of pulsing contacts which, in reality, constitute the interrupter contacts of the electromagnet. When the last ball of the selected group is restored to its normal position the circuit of the electromagnetic interrupter is openedand operation of its pulsing contacts is discontinued. Thus the number of balls displaced incident to the actuation of a key predetermines the number of impulses to be transmitted and the tuned striker functions to count oil the predetermined number of impulses at a speed or frequency corresponding to the frequency of vibration of the striker.

A feature of the invention resides in the use of manually operable keys for selectively displacing the balls which have normal, fully depressed and intermediate positions whereby the ball camming portion of the key after having been fully depressed to displace a particular group of balls is returned to its intermediate position in which it clears the balls and thereby allows freedom of movement of the balls in their return to normal positions under control of the tuned striker.

Another feature of the invention contemplates the use of switching means which function when a key is fully depressed for preparing the electromagnetic interrupter for inclusion in thepulsing circuit and which complete the effective inclusion of the interrupter in the pulsing circuit only when the key has attained its intermediate position. This feature precludes the premature operation of the pulsingcontacts and precludes the functioning of the interrupter until the ball movin cam portion of the key has been removed from the line of travel of the balls. This feature also precludes the false operation of the transmitter should the operating subscriber hold a key in its fully depressed position for an abnormal interval of time.

In accordance with another feature or the invention latching means is provided which functions to lock an actuated key in its intermediate position. An ancillary feature provides means whereby the last ball restored to normal position under the influence of the tuned striker serves to operate the latching means and to effect the restoration of the actuated key.

These and other features of the invention will be better understood from the following detailed description when read in connection with the accompanying drawings, in which:

Fig. 1 is a front elevation of the impulse transmitter of this invention mounted within the base of a telephone set;

Fig. 2 is a view of the impulse" transmitter taken along the line 2-2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a view of a portion of the impulse transmitter taken along the line 3--3 of Fig. 2, looking in the direction of the arrows;

Fig. 4 is a view similar in part to that shown in Fig. 1 and shows the transmitter with one of the manually operable keys in its operated position; and

Fig. 5 is a combined circuit and structural schematic illustrating the various switching elements controlled by the transmitter and their locations in the line circuit of a telephone subscribers station.

A permanent magnet consisting of an elongated flat piece i and two oppositely disposed integrally formed pole-pieces H and I is secured to the base |2 of the telephone set 9 by means of screws l3. Fixed to the piece l0 also by the screws I3 is an insulating trough-like member 14. This member 14 is made up of a base piece which rests upon the magnet piece l0 and two integrally formed sides which extend the entire length of the permanent magnet. The upper ends of the member H are turned in to partially enclose the area defined by the insulating base piece, its two sides and the permanent magnet poles l4 and I5. This insulatin structure forms a race or receptacle for ten balls l6 of resilient magnetic material. The receptacle H is slightly longer than the space occupied by the ten balls when in contact one with another and the partial enclosure effected by the inturned upper edges of the sides precludes the possibility of the balls falling out of the receptacle while permitting them freedom of motion therein.

The U-shaped permanent magnet serves to hold the balls in the normal position illustrated in Fig. 1 and also in whatever positions the balls are moved to incident to the actuation of the keys 29. The balls l6 are so normally positioned in the receptacle N that the ball on the extreme right of the row, viewing Fig. 1, touches the permanent magnet pole l5 and the ball on the extreme left is spaced from the pole I. As above indicated, the ten balls are held in this position by the action of the permanent magnet.

Brackets II and I! are fixed to the base l2 by screws 23. These brackets, located one at either .end of the base, provide means for mounting a slidable latch plate 2|, a fixed plate 22 and a stop member comprising two angularly disposed integrally formed portions II and IT.

The latch plate 2| is provided at each end with a slot 23 and is slidably held on the upper flanges of the brackets I3 and I 3 by screws 2| which screw into the bracket flanges in such a manner that the shank portions of the screws constitute guides which pass through th slots 23 and allow the plate 2| to move freely longitudinally. The plate 2| is provided with ten spaced apertures or oriflees 27 for a purpose to be set forth hereinafter.

The plate 22 is stationary and is fixed to the brackets l8 and I! by screws 23. This plate 22 is located below the slidable latch plate 2| and is provided with ten circular openings 30 and a larger substantially rectangular aperture 44 located near the left end of the plate.

The stop member comprising a weighted portion 40 and a stop portion I1 is pivotally mounted on a rod 41 which is supported by two integrally formed arms 42 of the bracket Hi. The hole or aperture 44 in plate 22 permits freedom of movement of the stop member when pivoting on the rod 4|. A spring 43 having one end fixed to the underside of the weighted portion 40 and its other end fixed to a pin mounted on the upper edge of permanent magnet pole l4 assists in restoring the stop member to its normal position, illustrated in Fig. 1. In this position the stop portion I1 is located between the inner face of pole 4 and the ball IS on the extreme left of the row.

The ten balls l6 are displaceable from normal to alternate positions in groups of one to ten balls by means of the keys 29. Each key 29 consists of a shank portion 3|, a camming portion 28 and a button, designated 29, all of which are formed integrally, or associated in such a manner as to constitute a unitary structure. The shank portion 3| of each key is located immediately over one of the balls l6 and has its end beveled for engaging its respective 'ball and camming it to the left when the key is manually depressed. A coil spring 33 is wound around the shank portion 3| of each key and has one end embedded in the shank and the other end fixed to the stationary plate 22. These springs serve to restore the keys after manual actuation and automatic release by the latch plate 2|, as will appear from a later de scription.

The cam section 28 of each key, interposed between the shank and button, has one edge beveled and is provided with a detent or catch 36 projecting from the lower opposite edge. when a key is depressed, the beveled edge of the cam portion 28 acts upon the edge of a corresponding aperture 21 in plate 2| and cams the plate to the left. As indicated more clearly in Fig. 4, the keys 29 have normal, intermediate and fully depressed positions. As the key is depressed, the beveled end of its shank portion 3| engages the ball l6 directly below it and cams the ball, and all other balls to the left in the row, so as to move it, or them to their alternate positions, in which the first ball on the left of the row contacts the permanent magnet pole I. This alternate position of the balls is attained when the actuated key is fully depressed. It will be observed that when a key is fully depressed the catch 36 has moved considerably below the under surface of the latch plate 2| so that when the finger is removed from the depressed key the spring 33 associated therewith functions to restore the key to its intermediate position, in which the catch 38 engages the under surface of the plate 2| causing the key to be locked.

A cam bracket 38 is fixed to the under-side of the-latch plate 2| by means of screw 33 and, as shown in Fig. 1, normally is in contact with the end of the weighted portion 40 of the stop member. When the plate 2| moves to the left, incident to the operation of a key, the stop is caused to rotate on its rod 4| in a counter-clockwise direction. In this mannerthe stop portion I1 is raised from its normal position to permit free movement of the balls IE to the left. It will be observed,

by referring to Fig. 4, that the first ball in the row serves to further raise the stop and when the first ball contacts the pole it the stop portion 11 rests thereon and is held thereby in the position illustrated. when any group of balls is moved to the left so as to occupy their alternate positions they are held by the action of the permanent ma net.

The purpose of providing three positions for the keys 29 is to remove the shank portions thereof from the path of the balls it after actuating them to their alternate positions and thereby allow the balls to be returned to their normal positions without interference from the key shanks. In their intermediate positions the key shanks are lifted clear of the balls as shown in Fig. 4 and do not hinder the balls in their return movement. It is obvious from Figs, 1 and 4 that the first key 29 to the left functions, when depressed, to move the first ball i8 to the left of the row into engagement with pole H; the second key functions to move the first two balls; the third key moves the first three balls, and so on.

The shank portion 3| of each key is provided with a projecting pin it! which normally clears the upper edge of a pivotal member 65. This memher is mounted on a rod 84 carried by the earlike extensions 85 of a bracket. The bracket 66 is located to the rear of the permanent magnet and is secured to the base M by screws .81.

This bracket is substantially of the same length as the pivoted member 63 and carries two inte rally formed lugs 93 and 94 against which similarly formed lugs 9i and 92 on the pivoted member 63 rest when the member $3 is in its normal position. The member '83 is held in its normal position by the-action of coil springs Nib, one end of each of which is fixed to the, member 83, the other ends being fastened to the stationary plate 22. The purpose of the pivotal member 53, which is common to all keys, is to operate springs 60, M, 8| and 65 carried by bracket b8 and more specifically to move spring iii out of engagement with spring Wand spring bi into engagement withspring Bil during the downstroke of the keys, and to permit the spring st to reengage spring 85 and spring hi! to disengage spring 80 when the key assumes its locked intermediate position. The actuation of springs 8i and 81' is efiected by arms 82 and 82 respectively which extend from the right of the member 83. The

, functions of springs 88, 80'. Si and l will appear from a later description. Suffice it to say at this time that when 'a key assumes its intermed ate position spring 8i reengages spring 80 before spring 6i moves out of engagement with spring 60'.

Secured to the left central portion of the base I2 is a bracket 45. Viewing Fig. 3, this bracket 45 is provided with a forwardly projecting extension to which the electromagnet 48 is secured by screws. The bracket 45 is contlguously associated with the core 41 of the magnet 46 and constitutes a portion of the magnetic circuit. The

lower end of the bracket 45, still viewing Fig. 8, is provided with a vertical. extension which coop:

, crates with an L-shaped bracket Si in supporting the armature 49 and contact springs 50 and 90. The bracket BI is secured to the base I! by screws.

.The springs 5b and 90 are insulated from the armature 49 and from each other, while the armature makes direct contact with the vertical extension of bracket 45. The armature 49 carries a polepiece 48 in juxtaposition to the free end of ma net core 41. Atits extreme outer end the armature carries a ball 52 which is similar in construction and dimensions to the balls l8. The armature 49, with its pole-piece 48 and ball 52, is designed to vibrate, at a particular predetermined frequency, or speed which corresponds to the speed at which it is desired to transmit pulses. The spring 98 is associated with the magnet armature 19 in such a manner that it responds faithfully to any movement of the armature. Thus, when the armature is attracted by the magnet 46 the spring 80 is moved out of engagement with spring 58 and when the electromagnet is deenergized the armature releases and causes spring 90 to reengage spring 50. The purpose of these springs will be set forth in detail in connection with a description of Fig. 5 to be made hereinafter.

The first ball 16 to the left of the row of balls has fixed thereto a spring 55 which extends inwardly from the ball. This spring functions, when operated, to actuate the make-before-break springs 58 and 51. The springs 58 and 51 and the rear end of spring 55 are insulatively'supported between two L-shaped brackets 85 fixed to the base i2 by screws. The insulating receptacle 14 is cut away at H'll to permit movement of the spring 56.

Referring now to Fig. 5, the subscriber's subset S is normally connected to the line L by way of contact springs 58 and 51. The circuit for the electromagnet 48 extends from one of the line conductors and includes contact springs 58 and 90, winding of magnet 48, normally closed contacts 80 and 8! and spring 55 which is normally disengaged from spring 58. Thus the winding of magnet 48 is normally excluded from the line circuit L. When a key 29 is depressed; one Or more balls I8 are moved to the left so that the first ball to the left of the row engagesthe permanent magnet pole i4. As the first ball moves to its alternate position the spring 55 moves so as to cause spring 56 to disengage spring 51. It will be recalled that during the depression of any key 29 the pivoted member 83 is engaged by the pin 10 associated with the depressed key and moves so as to operate the spring pile-up comprising contact springs 8B, 8!, 86' and 8|. Since the member 83 functions during the downstroke of the key and spring 85 functions when the key is fully depressed, the

springs 60, 8|, and 6| are operated before the contact springs 58, 5t" and 55. The springs 80' and 8| accordingly close to maintain the subset S across the line pending the reconnection of magnet 46 to the line and thereby to preclude the possibility of a lost connection, it being understood that the contacts 58 and 51 open when the key is fully depressed and thus open one of the substation connections to the line. Thus when the key is fully depressed the subset S is still connected to the line and the circuit to magnet 48 is opened at springs 80 and 8|. When the key is released and-thereby assumes its intermediate locked position, contact spring 8| reengages spring 80 just prior to the separation of contact springs 80' and 8| so that the winding of magnet 48 is effectively includeddn the line circuit. The circuit for magnet 48 includes the contact springs 58 and 88, winding of magnet 48, closed springs 80 and 8|, and springs 55 and 58. The purpose of springs 88 and 8| is to preclude the effective inclusion of magnet 48 in the line L until the depressed key has been released and has assumed its intermediate locked position. Unless such precaution is taken and the magnet is included in the line when the key is fully depressed it would immediately start to operate as an interrupter to actuate latch plate disengages the pulsing contacts "-40 and this operation of the magnet would persist as long as the operator or subscriber maintained the key in its fully depressed position. The consequent operation of the pulsing contacts would result in false connections.

When the magnet 48 is effectively included in the line circuit it functions as an interrupter on current from the source 93 located at a central oflice. Obviously the magnet would function indefinitely as an interrupter to operate springs 50 and 90 and correspondingly effect the transmission of impulses since the springs 50 and 90 are connected in series with the line and the winding of the magnet. However, the number of times the armature 49 operates and therefore, the number 01' times the pulsing circuit is interrupted to transmit impulses is determined by the number of balls that have been moved to their alternate positions incident to the actuation of a key. For example, assuming the fourth key from the left is actuated,

four balls ii are moved to the left so that the first 1 ball thereof contacts permanent magnet pole ll. When the magnet 48 starts to operate as an interrupter, the ball 52 fixed to the armature 43 of the magnet strikes pole ll once for each energiration of the magnet. Upon the first impact of ball 52 on pole II the fourth ball of the selected group is driven back to its normal position; the second impact causes the third ball to be returnedto its normal position; the third impact causes the second ball to return to its normal position; and the fourth impact returns the first ball 'to its normal position, When the first ball is returned to its normal position, the spring 55 restores to normal causing spring 56 to reengage the spring 51. Thus the operating circuit for magnet I8 is opened. at spring 51 and the subset S is reconnected to the .line. The opening of the circuit to magnet 46 precludes any further operation of the armature l9 and any further operation or the pulsing springs 50, and the electrical circuit assumes its normal unoperated condition. Thus, four pulses are transmitted incident to the actuation of the fourth key.

When the first ball in the row is returned to normal as described above, the stop "-41 falls back to its normal position due to the action of gravity on the weighted portion and to the action of spring 43. The weighted portion 40 thus engages the cam bracket 38 and cams the Latch plate 2| to the right. This movement of the the catch 36 and permits the depressed key 29 to restore to normal under the action of its spring 33. The member 63 thereupon returns to normal and the springs 60, BI and GI restore. The transmitter is thus restored to normal.

In practice, each key of the impulse transmitter of this invention carries designation characters or symbols corresponding to those appearing on the number plate of the well-known flngerwheel dial. For example, the first key would bear the numeral 1"; the second key, the characters ABC2; the third key, the characters DEF3; etc.

.The telephone set casing is provided with ten cylindrical compartments 30 in which the button end of the key 29 moves when depressed. The diameter of the compartments is slightly greater than that of the collar 34 associated with each key so as to permit free movement of the keys therein.

A stop 8| is provided on the pole l4 and provides a rest for the stop Ill-I1.

The transmitter of this invention functions to transmit a number of impulses corresponding to the number of balls selectively displaced by the manual operation of any of a plurality of keys, and the selected number of impulses is transmitted at a frequency or speed determined by the mechanical tuning of the electromagnet armature.

While the embodiment of the invention described in the specification involves the use 01 magnetic balls, it is readily apparent that the transmitter is not limited to the use of such balls and that it will function equally well with nonmagnetic balls provided some simple expedient is resorted to in holding the balls in their normal and alternate positions. Such means may take the form of non-linear springs or toggles, the principle of operation of such mechanisms being well known.

What is claimed is: V

l. The combination, in an impulse transmitter, of an electromagnet, an armature for said electromagnet, pulsing contacts controlled by said armature, and an impulse counter comprising a row of ten resilient magnetic balls, a magnetic circuit for holding said balls normally in contact with one another comprising a permanent magnet having two oppositely disposed poles against one of which the last ball of said row rests, manually operable key means having fully depressed and intermediate positions, means controlled by said key means when fully depressed for selectively dividing said row of balls into two groups containing one to ten balls and moving a selected group so that the first ball of the selected 4 group is moved into engagement with the other pole of said permanent magnet, means controlled by the first ball of the selected group when thus moved for preparing an operating circuit for said electromagnet, means for locking said key means in its intermediate position, means controlled by said key means in its intermediate position for completing the operating circuit for said electro magnet whereupon said electromagnet causes said armature to vibrate and actuate said pulsing contacts, means controlled by said armature when vibrated for repeatedly striking the other pole of said permanent magnet to cause the balls of the selected group to be driven back individually to their normal positions,'means controlled by the first ball of the selected group when driven back to its normal position for opening the operating circuit for said electromagnet, and other means controlled by said first ball for releasing said key means.

2. An impulse transmitter for use at a telephone subscriber's station for transmitting impulses suitable for actuating automatic switches employed in extending a call initiated at the said station, comprising, in a unitary structure, a normally positioned row of contiguously associated balls, a plurality of manually operable keys corresponding in number to the number of balls in said row and each key having normal, fully depressed and intermediate positions, pulsing contacts, an electromagnet having a vibratable armature for controlling said contacts, a normally open control circuit for said electromagnet, means integral with each of said keys and eilective when its corresponding key is fully depressed for moving a predetermined number Of the balls of said row from their normal positions, means for restoring the fully depressed key to its intermediate position, means effective only when said key has been fully depressed and then restored to its intermediate position for closing the cono,ss1,o7s

' trol circuit of said eiectromagnet whereupon said.

electromagnet functions to vibrate its armature and said pulsing contacts are operated once for each vibration of said armature, means controlled by said armature for restoring one ball of said predetermined number of balls to its normal position for each vibration of said armature, and means controlled by the last ball restored for opening the control circuit of said electromagnet and for restoring said key to its normal position.

3. The combination, in an impulse transmitter, of pulsing contacts, a vibratable member for operating said pulsing contacts once tor each vibration thereof, an electromagnet for vibrating said member, a plurality of balls normally contiguously associated so as to form a continuous row, a

normally open operating circuit for said eiectromagnet, a plurality of manually operable keys each having a normal, a fully depressed and an intermediate position, means controlled by each of said keys when manually moved to its fully depressed .position' for separating a predetermined number of balls from the said continuous row of balls, means controlled by one of the balls I of the separated predetermined number of balls for preparing the operating circuit for said electromagnet, means for initiating the return of a fully depressed key, means for arresting the return movement of the key so as to maintain it in its intermediate position, means controlled by the key when in its intermediate position for completing the operating circuit for said electromagnet whereupon said electromagnet functions to vibrate said member, means including said member for restoring a ball oi said predetermined number of balls to normal position for each vibration of said member, and means controlled by the said one of said balls for opening the .operating circuit to said electromasnet and for simultaneously restoring the key to its normal position. v

a The combination, in an impulse transmitter, of an eiectrcmagnet, an armature for said electromagnet, pulsing contacts controlled by said armature, and means for predetermining the number of operations of said pulsing contacts by said armature comprising a row of resilient magnetic balls, a magnetic circuit for holding said balls normally in contact with one another comprising a permanent magnethaving two oppositely disposed poles against one of which the last ball of said row rests, a plurality of manually operable keys having normal, fully depressed and intermediate positions, means integral with each of said keys and effective upon the full depressionoi said keys for physically engaging said balls so as to separate said row into two sections and for moving one of said sections so that the first ball of said ro engages the other pole of said permanent magnet, means controlled by the first ball when thus moved for preparing an operating circuit for said electromagnet, means for returning said keys from their fully depressed positions, means for arresting said keys in their intermediate positions, means controlled by said keys in their intermediate positions for completing the operating circuit for said electromagnet whereupon said electromagnet causes said armature to vibrate and actuate said pulsing contacts, means controlled by said armature when vibrated for driving the balls of the said moved section to their normal positions one at a time, means controlled by the said iirst ball of said row when driven back to its normal position for opening the operating circuit to said eleetromagnet, and other means controlled by the said first bail for restoring said key to their normal positions.

a '1 ROBERT C.

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