US2290448A - Telephone impulse sender - Google Patents

Description

y c. c. PUCKETTE 2,290,448

- TELEPHONE IMPULSESENDER Filed Jan. 11, 1940' 5 Sheets-Sheet 1 I NVEN TOR CHARLES CLARKE PUCK ZTTE y 1942- c. c. PUCKETTE 2,290,448

TELEPHONE IMPULSE J. SENDER Filed Jan. 11, 1940 3 shee s-sheet 2 SPRING HOUSING FIG; IA

I] com OPERATED 1 CONTACTS IMPULSE SPRIN)GS I2 TRANSMITTER SHUNT 1% 1 g /SPR|NG S) v n INVENTOR. CHARLES CLARKE PUCKETTE Z ATTO RNE Y.

July 21, 1942. c. c. PUCKETTE TELEPHONE IMPULSE'SENDER Filed Jan. 11, 1940 3 Sheets-Sheet 3 INVEN' 'OR. (uARLE CLARKE PUCKETTE lulunm ATTO EY the digits or 9 Patented July 21, 1942 A TELEPHONE HWPULSE SENDER Charles Clarke Puckett Signor to The Gener e, Coventry, England, as-

al Electric Company Limited, London, England, a British company Application January 11, 1940, Serial No. 313,396 In Great Britain January 25, 1939 Claims.

The present invention relates to impulse senders of the type used in telephone systems, and more particularly to the type of impulse sender prov ded in connection with telephone instruments having coin collecting facilities, that is to say, so-called pay stations. The object of the invention is to provide a means for ensuring that only certain types of call can be made from the instrument without payment.

In connection with such instruments, it is known to provide means whereby the impulse sender is rendered inefiective until after the insertion of suitable coins, unless a predetermined number or numbers is first dialled. Thus for example, if the digit 0 is dialled, the user of the instrument must be enabled to connect with the operator, while if the digits 99 for example are dialled, the user must be put in connection with the fire or police station or some such public service. It must be impossible for the user to obtain free calls to any numbers other than those specified. This has previously been performed by arranging that the impulse springs of the dial are normally shortcircuited by contacts which are opened only when are initially dialled, the said short-circuiting contacts being reclosed near the end of the return motion of the finger plate. If, however, the finger-plate is prevented from returning completely to normal after the free digit has been dialled, the user may be enabled to obtain a call to which he is not entitled without payment.

According to th invention, such unauthorised free calls are prevented by the provision of means whereby impulsing is suppressed or interfered with if, after the dialling of the initial free digit, the finger-plate of the dial is not allowed to return completely to normal or if its return motion is reversed prior to its having reached such a position, such suppression being effective until complete restoration of the finger-plate to normal has been made.

In one embodiment of the invention, the normal impulse spring short-circuiting contacts are provided, these contacts being opened only when a permissible free digit is dialled. During the wind-up period of the dial made by the subscriber to obtain such a free call,'a lever is; moved by means of a projection rotated by the centre shaft of the dial, and locks, the lever being provided on, and hinged to, the base-plate of the dial. If the dial is used correctly, i. e. if the finger-plate is allowed to return completely to normal, the lever restores to a normal position is deeper than all the others,

shortly after the short-circuiting springs close during the return motion of' the finger-plate. If, however, the movement of the dial in the impulse sending direction is arrested before the said contacts short-circuit the impulse springs, the said lever is left in an off-normal position. Reversal of the direction of the motion of the finger-plate new results in a sliding member carried by the lever engaging witha portion of the dial mechanism, the said sliding member being transposed to such a position that when the finger-plate is once more allowed to turn in an impulse-sending direction a projection on the sliding member prevents impulses from being sent by holding the impulse sending springs either opened or closed. The sliding member and lever can only be restored to their normal positions when the finger-plate of the dial has been allowed to restore completely to normal, so that the impulse spring short-circuiting contacts have been closed.

In an alternative embodiment of the invention, more particularly applicable to the type of impulse sender disclosed in my application Serial No. 289,949, filed August 14, 1939, a rocker is provided in connection with a lever arm, the said rocker being turned through an angle during the Wind-up period of the dial and backwards through the'same angle during the sending portion of the 'dial movement, the said angular movement being for the purpose of providing a predetermined degree of lost motion. In an impulse sender of this type provided with impulse spring short-circuiting contacts of the type already described, it is arranged that the initial angular movement of the rocker takes place only if the winding-up motion of the dial is commenced When the finger-plate is in its normal position. This is ensured by arranging that the first slot in the impulse producing wheel the rocker being so dimensioned that it slips'over the top of the teeth if any attempt is made to wind-up the dial from'any position other than normal. If an improper manipulation of the dial is attempted by arresting the dial during its return mo tion, it is found that pauses are produced which interfere with the production of free impulse trains other than those for which the dial is designed.

As an additional safeguard it may be desirable to provide a slipping cam which is moved into the path of the rocker if reversal of the direction of the finger-plate talges place during its return to a normal position. This cam holds the rocker in such a position that the impulse producing springs remain with their contacts open so that any connection which is being set up is dropped during the winding-up time of the dial.

A further device is also employed to ensure that the short-circuiting contacts are closed after a free digit has been dialled. If the dial is allowed to return to such a position that the rocker pin drops into the first slot in the impulse producing wheel (which takes place just prior to the closure of the short-circuiting springs), it is arranged that the rocker, during the next winding up of the dial, closes the said short-circuiting springs, which remain in this condition until another free digit is dialled. Thus it is impossible to dial a succession of other than free digits without causing the impulse springs to be either short-circuited, or opened for a period long enough to drop or mutilate any connection which may have been partially set up.

In order that the nature of the invention may be properly appreciated, reference should be made to the accompanying drawings in which Figures 1 and 3 represent alternative embodiments of my invention and Figures 2 and 4 show the said embodiments in operated positions.

In connection with impulse senders fitted to pay-stations, it is usual toprovide means whereby one or more predetermined digits can be dialled without payment. For example the digit is employed to connect the caller to an operator while the digits 999 are dialled by a caller who requires to be connected with an operator at a special manual position dealing with emergency calls. In order to permit such calls to be made without payment, it is usual to provide spring contacts which normally short-circuit the impulsing contacts until the impulse sender finger plate is rotated to a digit for which payment is not demanded, for example the digits 9 or 9. The short-circuiting springs are then opened and remain in this position during the return of the finger plate to its normal position when they again connect a short-circuit across the impulse springs. It is not possible to restore the shortcircuiting springs to. their normal position until after the last impulse of the digit has been transmitted because they would otherwise shorten the period of the last impulse. It is possible there? fore for a dishonest person dialling one of the predetermined digits without removing the telephone from its rest to prevent the finger plate returning fully to its home position so that the short-circuiting springs remain in the operated position which they assumed when the finger plate was rotated to the predetermined digit. If the telephone is now removed from its rest, the caller may dial a number comprising any digits providing that the finger plate is prevented from returning to normal after the dialling of each digit so that the short-circuiting springs remain throughout in their operated position.

Another means of defeating the object of the short-circuiting springs is to rotate the finger plate to one of the predetermined digits for which payment is not required and then to arrest the finger plate on its return when the number of impulses according to the required digit has been transmitted. In this case the short-circuiting springs remain open after the dialling of each digit and it is possible by the aforesaid means to obtain connection with the wanted subscribers line without payment. Having completed the dialling of the wanted number, the caller waits for a short period before allowing the impulse sender finger plate to return to its normal position, the impulses transmitted at this time being rendered ineffective because the exchange switching means will have completed its function of extending the call to the wanted subscribers line.

The examples illustrated provide means whereby interference with the motion of the impulse sender finger plate according to both of the methods above described, is rendered ineffective to provide unauthorised free calls.

Fig. 1 is a back view of an impulse sender embodying my invention.

Fig. 1A is a partial section of the sender of Fig. 1 taken in direction of the arrows along line la-la.

Fig. 1B is a diagrammatic circuit of a telephone substation of known type, showing the coin operated springs and with the addition of the springs l l to open the shunt around the impulse springs.

Fig. 2 is a partial back view of the sender of 1 in an off-normal position.

Fig. 3 is a back view of a modified form of sender.

Fig. 4 is a partial back view of the sender of Fig. 3 in an oiT-normal position.

One embodiment of the invention may be understood by reference to Figures 1, 1A, 1B and 2 which show an impulse sender of the type described in my above-mentioned application Serial No, 289,949 filed Aug. 14, 1939, to which has been added an impulsing contact short-circuiting springset H operated by a spring [2 having a V-shaped section resting on the profile of a rotatable cam 13. Cam I3 is loosely mounted on the dial shaft and normally held from rotation with the shaft by the tension of spring !2, and is only moved when stud 22 engages one of the pins I9, 20 or 2!. A lever I4 is positioned at one end on a pivot Hi, the said lever being capable of occupying either of the two extreme positions shown in the two figures and carrying a sliding member H5. The sliding member has an endwise movement limited by the two studs H and I8 which are fixed to the lever and pass through slotted holes 28 and 29 in the member I6. Pins [9, 20 and 21 are screwed into holes in cam I3, according to the values of the predetermined digits which may be dialled without payment. Pin 19 represents the digit 8, pin 29 the digit 9 and pin 2| the digit 0.

When the finger plate is rotated to a position corresponding to one of the digits 8, 9 or 0, a projection 23 on the restoring spring housing (shown in Fig. 1A) is rotated in an anti-clockwise direction (as seen in Fig. 1) and thereby allows spring 24 to rest against a projection 31 of the lever 14 ready to hold the latter eventue ally in an off-normal position. During a further portion of its travel the projection 23 comes into contact with the underside of the lever M which is consequently raised so that the upper extremity of spring 24 falls into a catch portion 31 on the projection of the lever I4 (as shown in Fig. 2) and provides a means for maintaining the lever in its raised position. During the fur-. ther travel of the finger plate, a stud 22 secured to the driving spindle moves against pin I9 which is screwed into cam 13, whereupon the cam is rotated in an anti-clockwise direction with the result that the V-shaped section of the operating spring I2 is lowered from the portion of the profile on the cam upon which it normally rests into the deeper cut portion. The spring contacts now open and according to a circuit arrangement shown in Fig. 1B, remove a short-circuit from the impulsing springs.

When the finger plate isallowed to restore to normal, stud 22 moves back against pin 2| whereupon the cam I3 is rotated in a clockwise direction so that the V-shaped portion of the operating spring I 2 is raised to the profile of the cam upon which it normally rests, this taking place after completion of the last impulse. The short-circuiting springs now close.

During a later stage in the return of the finger plate, projection 23 pushes against spring 24 which moves out of engagement with notched element 3! of the lever 14 with the result that the lever is lowered to its normal position by means of the tension in spring 21.

Assume now that a person attempts to defeat the object of the short-circuiting springs by preventing the finger plate returning to normal after the last impulse has been transmitted but before the cam has rotated sufficiently to raise the V section of the operating spring I2. In this event the lever will not be restored because its restoration is subsequent to the raising of the operating spring. Should the finger plate be again rotated for the purpose of dialling a further digit, the rocker arm 25 which operates the impulse springs moves against a projection 26 on the sliding arm 16 which is moved along the path provided by its slots 28 and 29 in conjunction with studs I! and 8 until spring 2! falls into a slot in the sliding member (as shown in Fig. 2), thus preventing the member restoring to its normal position. A projection 30 on the sliding member is now in a position immediately below the arm 3| and maintains the arm in a raised position as shown in Figure 2. This is necessary in order to prevent the V-shaped projection 25 fouling the rocker arm. A stud 32 secured to the sliding member moves against an extension 33 of the upper impulsing contact spring and raises the spring to the position shown in Fig. 2 so that its contact disconnects itself from the contact of the lower impulsing spring, thereby providing a disconnection in the line circuit which causes the switching means at the central exchange to be released and prevents the caller obtaining the number he requires. The impulsing springs remain in the open position until the finger plate is allowed to restore to normal and the lever lowered as in the case of normal operation. When the lever returns to its normal position, the sliding member is lowered with it until the latter is free from the retaining spring 21. The sliding member is now restored to its normal position by means of the tension of spring 35 exerted against the stud 36 secured to the sliding member whereupon the stud 32 disengages with the extension 53 of the impulsing spring which restores and makes contact with its companion spring.

In the event that a person attempts to make a call by operating the finger plate to a position corresponding to one of the digits for which no charge is made and then arresting the finger plate on its return after the required number of impulses has been transmitted, the next movement of the finger plate in the operate direction results in the operation of the sliding member by the rocker arm as previously described, with the result that the impulsing springs are once again opened and any portion of a connection previously set up is released.

A further embodiment of the invention may be understood by reference to Figures 3 and 4 which again show an impulse sender of the type described in my application Serial No. 289,949, filed Aug. 14, 1939, to which has been added an impulsing contact short-circuiting springset 4!] operated by a spring 4| which normally rests on the profile of cam 42. A slipping cam 43 from which extends an arm 44 moves with the shaft within the limits provided by projections 45 and 46 on bracket 41. A spring 55 is tensioned against a stud 49 screwed into cam 42 which is similar to cam l3 of 'Figs. 1 and 1A. Pins 5|, 52 and 53 are screwed into holes in cam 42 according to the values of the predetermined digits which may be dialled without payment. A portion of the first slot 55 in the impulsing disc is deeper than the remaining portion of the slot in order that the lower end of rocker 56 may :be trapped therein for the purpose of reversing the angle of the rocker when the finger plate is rotated.

When the finger plate is rotated in an operate direction, the sliding cam 43 moves in a counterclockwise direction (as seen in Fig. 3) until the arm 44 strikes against projection 45. This is accomplished by means of frictional contact between the said cam and the main shaft. The lower end of rocker arm 55 falls into the slot 55 whereupon the rocker arm is moved with the impulsing disc. Stud 54 (shown in dotted lines in Fig. 3), which is rotated with the driving wheel and is similar to the stud 22 of Figs. 1 and 1A, eventually moves against pin 5| which causes cam 42 to rotate so that operating spring 4| falls into a lower portion of cam 42 as shown in Figure 4 where it is held by the tension of spring 4|. The impulse short-circuiting springs 40 now open and by a circuit arrangement such as shown in Fig. 1A at springs 1| disconnect a short-circuit from the impulsing springs.

When the finger plate is released, it restores in a counter-clockwise direction and after the last impulse has been transmitted stud 54 moves against pin 53 so that cam 42 is moved until spring 4| rests on the higher portion of the profile of cam 42 as shown in Figure 3 with the result that the impulse short-circuiting springs close.

Assume now that a person endeavours to defeat the object of the snort-circuiting springs by arresting the finger plate before it has completely restored but after the last impulse has been transmitted. In this event the impulse shortcircuiting springs will remain open because stud 54 does not move against pin 53 until after the last impulse has been transmitted. When the finger plate is again rotated, spring 4| is resting on the lower profile of cam 42 so that when the rocker arm 56 moves through an angle under the influence of the impulsing disc, the insulated bush 58 secured to the rocker arm moves against spring 4| so that the latter is lifted off the profile of cam 42 and springs 49 are consequently closed. The tension exerted by spring 55 against stud 49 now causes cam 42 to be rotated in a clockwise direction so that the short portion of its profile between the highest and'lowest portions becomes immediately underneath the lower extremity of the V section of spring 4|. When the finger plate is allowed to restore, rocker arm 56 moves through an angle under the influence of the first tooth of the impulsing disc. Spring 4| now rests on the short portion of the profile of cam 42, the short-circuiting springs remaining closed and preventing the caller from obtaining the number he requires.

In the event that a person attempts to make a call by operating the finger plate to a position corresponding to one of the digits for which no charge is made and then arresting the finger plate on its return after the required number of impulses has been transmitted, the next forward movement of the finger plate in the operate direction results in the lower end of rocker arm 56 riding over one of the teeth in the impulsing disc because the angle of the rocker arm can only be altered by the slot 55 in the impulsing wheel. This is because the felt washer 59 stops the rocker arm falling deeply into each tooth gap, and hence prevents it from catching on any tooth other than the first. Sliding cam 43 moves to a position underneath the insulated bush 58. When the latter is raised by one of the teeth in the impulse wheel, it remains suspended on the sliding cam with the result that spring 57 is raised and the impulsing springs remain open until the finger plate is allowed to restore to normal. The caller is therefore prevented from obtaining the number he has dialled.

It will be seen from the foregoing. construction that correct and incorrect reverse or wind-up motions of the impulse sender are distinguished from one another by the depth to which the rocker. is allowed to sink into the teeth of the impulse wheel, i. e. the rocker can only be turned through its full lost motion angle by engagement with the deep slot preceding the first tooth. From this it follows that the rocker makes contact with the root of each slot during the return motion of the finger plate to normal, and consequently clicking would be produced if no felt washer were used. Conversely, if a washer is provided, then friction of the rocker against the washer may be regarded as undesirable on the grounds that particles of felt may become detached and act to choke the movements of the mechanism, and also that continued tapping of the rocker on the felt may cause it to change its shape, thus affecting the depth to which the rocker can drop into the slots.

It is proposed to overcome these objections by arranging that the rocker is prevented by spring means from dropping to the root of each tooth.

It is therefore provided with a spur, this being engaged when the rocker is in a normal position only, by an additional projection or tooth carried by the dial spindle. If the finger plate is allowed to return to a normal position, this extra projection catches the rocker during the subsequent wind-up period, moving it through its full lost motion with the result that impulsing is produced during the return motion of the finger plate.

If, however, the finger plate is not allowed to return to its fullest extent, a member similar to that shown and described under the number 43 in Figure 3 is moved, during subsequent reverse motion, into engagement with the rocker, which does not rotate through its lost motion period. This causes opening of the impulse springs as previously described and the whole or partial connection previously set up is dropped.

By this construction, it is possible to arrange that substantially no clicks occur during the winding up and impulsing' periods, and that the rocker arm does not come into contact with any felt or similar friable material.

I claim:

1. An impulse sender for paystation telephones, having a finger dial and means controlled thereby for transmitting impulses, means for suppressing all impulses when certain digits are dialed, means for preventing the operation of said suppressing means digit is dialed, and means operated only if the finger dial is not completely returned to normal after the transmission of a digit of the last type for causing suppression of further impulses.

2. An impulse sender for paystation telephones having a finger dial and impulse contacts controlled on the return of the dial to normal after operation to transmit impulses, of means controlled by the attempted further operation of the dial only when operated before it returns to normal for preventing further effective operation of said impulse contacts.

3. A calling device for telephone paystations, having a finger dial and contacts controlled thereby to send impulses, shunt springs for maintaining the impulse contacts ineffective, means for opening said shunt springs only after a predetermined digit has been dialled and for closing said shunt springs in the interval of movement of the dial between the last operation of said contacts and the return of the dial to nor mal, and means controlled by the further operation of the dial only when reoperated before being completely returned to normal for closing said shunt springs.

4. A calling device as claimed in claim 2 having a lever, means for moving the lever to an off normal position on the forward movement of the finger dial, and means on the lever for operating said impulse springs for a time sufficient to render the impulses ineffective if the dial is again operated before it has completely returned to normal after a previous operation.

5. In an impulse sender having a finger dial and contacts operated thereb when the dial is moved and returned to normal, a rocker arm operating the contacts as the dial returns to normal to send impulses, and means for engaging said rocker arm to prevent its operation by the dial in a subsequent operation until the dial has completely returned to normal.

CHARLES CLARKE PUCKETTE.

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