US2165766A - Impulse sender for use in telephone systems - Google Patents

Description

c. c. PUCKETTE 2,165,766

Filed Feb. e, 1957 r 2 Sheets-Sheet i IMPULSE SENDER FOR USE IN TELEPHONE SYSTEMS Jul 11, 1939.

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IMPULSE SENDER FOR USE IN TELEPHONE sYSTEMS Filed Fb. 6, 1957 2 Sheets-Sheet 2 Patented July 11, 1939 UNiTED STATES PATENT creme IMPULSE SENDER FOR USE IN TELEPHONE SYSTEMS Application February 6, 1937, Serial No. 124,377 In Great Britain March 2, 1936 9 Claims.

The present invention relates to impulse senders for use in automatic telephone systems, and has for its object the provision of means whereby a predetermined signal may be sent by a subscriber with the least possible amount of'effort.

In cases of emergency such as a fire, it has been found that telephone subscribers forget the number for calling suitable assistance, or alternatively that the number is dialled incorrectly. The present invention aims to provide an impulse sending device whereby the only actions required of the subscriber are simple, such as the removal of the receiver and a single extra operation consisting of pulling a knob situated at a convenient place on the telephone instrument, these operations resulting in the emission of an impulse train which calls the fire station, police or other suitable source of assistance, the subscriber being then required merely to give his address. In connection with an impulse sending device of this nature it is also essential to ensure that no impulses shall be emitted by false operation of the knob, that it shall operate independently of the normal calling means of the subscriber and that the said normal calling means shall itself act independently of the emergency calling means.

According to the invention a calling device for use by a subscriber connected to an automatic telephone system comprises a knob, handle or key suitably located'on or near the subscribers instrument, means whereby operation of the said knob or the like causes emission of a predetermined impulse train, and means whereby the said impulse train, once started, is emitted in full independently of any further operation of the originating knob or the like.

In an embodiment of the invention, an auto-v matic impulse sender is made in the form of a flattened box, which may be aflixed to the base of an existing telephone, or may be incorporated in the base or body. The said impulse sender comprises a disc provided with a channeled edge, in which channel lies a cord connected to a knob of suitable colour such as red, placed at the front of the instrument. When the knob is pulled the disc is rotated against the tension of a spiral spring and a pawl carried by it engages with a movable plunger fixed to a second disc.

This second disc is provided at its periphery with a number of gear teeth which engage with the teeth of a governor wheel, this latter co-opcrating by means of a worm drive with a centrifugal type governor. Operation of the said two discs by the cord causes a free-wheel action to take place enabling the second disc to rotate without driving the governor.

The two discs previously mentioned, during rotation, carry with them two further discs, one of these, the third, being provided with teeth which later engage with the impulsing contacts. Complete operation of the cord results in all the discs being carried round until a projection on the fourth disc engages with a masking cam lying parallel with the said discs all of which are arranged with their axes coincident. The masking cam is turned until it enables the impulsing contacts to engage with the teeth of the third disc.

When the cord is pulled to its fullest extent, the plunger carried by the second disc is moved into engagement with a depression on the fourth disc, causing its lower end to lose contact with the pawl carried by the first disc. This latter is now freed and no further operation either forward or backwards by the subscriber can aifect impulse sending until the complete train has been sent.

The disc carrying the gear teeth is now locked to the remaining discs, and returns these slowly to normal under the influence of a further spiral spring. The rate of return to normal is controlled by the governor, and during this return motion an impulse train of predetermined character is emitted by the impulsing contacts provided that the subscribers receiver has been removed. When the train has been completed, the masking cam is returned to a normal position, causing one portion of its periphery to cover the teeth of the impulse disc, so that backward rotation of the latter does not cause emission of impulses. The plunger is removed from the depression with which it had engaged during return motion and the apparatus is once more ready to send out a further complete impulse train.

In order that the invention may be better understood reference should be made to the accompanying drawings, Figure 1 of which is a plan view and Figure 2 a section of a suitable embodiment.

From the drawings, it will be seen that the apparatus comprises a box-like structure erected upon a base plate 2 and enclosed within a cover i. A central spindle 3 is affixed to the base plate and carries the discs of which the apparatus is chiefly composed. Through the cover extends a cord 5 which terminates in a coloured knob 4, the cord being wrapped round a pulley or channeled disc 6 inside the cover. cord winds and unwinds correctly from the pulley. The latter is constrained by a spiral spring Guides 1 ensure that the i 8 so as to wind up the cord when the latter is left free.

On the cord pulley is mounted a pawl It! in such manner as to engage with the lower end of the plunger l2 which is pressed away from the cord pulley pawl by a helical spring H. The plunger remains normally in the position shown so that the winding up of the pulley by tension applied to the cord causes the pawl to engage with the plunger and rotate the discs with which the latter is associated.

The plunger and its spring and housing are fixed to a disc l3 provided with teeth around its periphery. These teeth engage with the small spur wheel l4 connected to a centrifugal governor mechanism [5 of known form. This mechanism is of the type used in telephone systems in connection with the automatic impulse sending dial, and is therefore not described in detail herein.

This mechanism is such that rotation of the disc i3 by pulling on the cord causes a freewheel action to take place which results in the said disc being able to rotate without driving the governor which only rotates (luring impulse sending.

This disc l3, besides carrying the plunger and operating the governor is coupled to a further spiral spring 29, this spring being for the purpose of returning the disc to its normal position as shown, during impulse sending. In addition, the disc {3 is also rigidly coupled by the plunger housing l9 and screws 11 to a disc 2| provided with spaced depressions around its edge, this disc being adapted to cause the emission of impulses of predetermined number and spacing in order to call a desired station. This impulse emission is performed by means of the impulsing springs 22 which again are of known form resembling those employed in the automatic dial.

It is, of course, essential that while the cord is being pulled, i. 6., during winding up, no impulses should be sent out, and that at completion of the winding operation impulses should be emitted which are of the required number and spacing independently of any other operations performed on the cord.

The first of these requirements is effected by means of the masking cam 23. As shown, this cam remains normally in such a position that extension of its edge holds the impulse springs 22 closed. The cam remains in this position during the winding up of the device by the cord, the projection 24 rotating clear of the plate 25 during this operation. When the rotating parts near the end of their travel, the projection 24 engages with a portion 31 of the cam 23, moving it so that the lug 28 leaves the pin 30 and the lug 9 terminates the motion of the cam. This allows the impulse springs 22 to rest on the edge of the impulse disc 2|, so that reverse rotation of the latter causes impulse emission. In addition, the off-normal springs 3| are opcrated as they now rest in the second or lower notch of the cam, this causing certain circuit changes to the apparatus.

A slight further motion of the cord now causes the disc 2! to slide a small distance relatively to disc 25, the extent of this sliding being limited by the length of the extended holes 35. At the end of this motion the upper end of the plunger i2 rises into the depression 36 formed in the plate 25, and its lower end loses contact with the pawl 10. This frees the discs I3, 2| and 25 from the pulley 6, so that the latter may be returned to a normal position, or left as at the end of the winding operation, without being able to affect the three previously mentioned discs in any way.

The three discs [3, 2| and 25 are now returned slowly to a normal position under the influence of the spring 20, the governor l5 now rotating and regulating the speed of the return motion. Since the cam 23 has unmasked the teeth of the disc 2| the impulse springs 22 now open and close as the teeth of the disc pass beneath them, impulse trains of the required number and spacing being emitted.

When the normal position is reached once more, the projection 24 presses against the slipping cam 23 and returns it to its normal position as shown. This causes cessation of impulsing. In addition, the discs l3 and 2| are driven further by the spring 20, the rounded end of the plunger l2 being thus forced out of the depression 36 against the pressure of the spring ll, so that it assumes its normal position. This return motion of the discs [3 and 2| continues until the screws passing through the holes 35 reach the extremity of their travel. The whole apparatus is now ready to be used once more when the pulley 6 is subsequently released, the pawl Ill then passing beneath the lower end of the plunger [2 and reengaging with it.

The apparatus is intended primarily for use with an ordinary telephone connected to an automatic exchange, in which case it would be necessary to remove the receiver before pulling the cord 5, since although it would be possible to cause the impulse sender to provide its own line loop, yet on return of the sender to normal this loop would be broken. It is therefore contemplated that the impulse springs 22 would be inserted in series with those of the normal impulse sender or dial mechanism used for ordinary calls. This arrangement however is not by any means essential. It would easily be possible to connect the impulse springs 22 in parallel with those of the normal dial, and arrange that the off-normal springs 3| performed such switching operations that the exchange apparatus was held in an operated position at the end of impulsing performed by the emergency calling apparatus until the subscriber lifted his receiver or performed some other minor re-setting operation such as the depression of a button fitted on the emergency calling apparatus. Such a device would not necessitate the removal of the subscribers receiver from the switchhook prior to its use.

The emergency impulse sending device is pref-- erably made in the form of a fiat box such as would be fitted beneath the base of the well known table form or desk pattern telephone, though such a position is not essential. The device could, if necessary, be mounted as a separate item close to the telephone or it might be incorporated in the bell box or terminal connecting strip if these are provided, separately from the telephone instrument.

Although the winding mechanism is shown as comprising a cord and pulley, any equivalent device such as a rack and pinion, spring returned to a normal position, or a handle rotating about the axis of the apparatus, may be employed instead.

I claim:

1. In a telephone system, an emergency impulse sending device having a single manual starting means, driving means, means responsive to one complete operation of said manual means for storing energy in said driving means and producing a complete code comprising impulses of predetermined number and spacing, and means for rendering said third means independent of said starting means during production of the code.

2. In a telephone system, an impulse sending device, said device including an impulsing cam normally held' at rest and associated driving means, means for rotating said cam to energize said driving means, means responsive to sufficient rotation thereof for releasing said cam from said rotating means to allow the cam to be driven back to its normal position, and means responsive to the return of the cam to its normal position for preparing said cam to receive another similar energizing rotation.

3. In an impulse sending device, an impulsing member normally held at rest by a restoring motor, another member normally held at rest by a restoring motor, a coupling established between said impulsing member and said other member while at rest, manual means for displacing said other member to effect the displacement of the impulsing member, means responsive to a predetermined displacement for removing said coupling to release said impulsing member, said last means effective also to reestablish said coupling responsive to the return of both of said members to their normal positions.

4. In an impulse sending device, an impulsing disc and a driving disc rotatable about a single axis, means for limiting the .rotation of said impulsing disc within definite limits, a pawl mounted upon the driving disc to engage a plunger mounted upon the impulsing disc for imparting rotation in one direction thereto, means effective when the impulsing disc reaches one extreme of rotation for lifting said plunger out of engagement with said pawl, restoring means to impart rotation in the opposite direction to said impulsing disc, said second means effective to return said plunger to a position in which it can be engaged by said pawl only upon the return of said impulsing disc to the other extreme of rotation.

5. In an impulse sending device, an impulsing disc and a driving disc rotatable about a single axis, each of said discs having a spiral spring tensioned to return it to a normal position when the disc is free, manual means for rotating the driving disc out of its normal position, a pawl mounted upon said driving disc to engage a plunger mounted in the impulsing disc to rotate said impulsing disc out of normal position responsive to said rotation of the driving disc, means responsive to a predetermined displacement of said impulsing disc for disengaging said plunger from said pawl, means responsive to the return of said impulsing disc to its normal position for returning said plunger to a position in which it may be engaged by said pawl.

6. In an impulse sending device, an impulsing disc mounted upon the same shaft with a driving disc and a slipping disc, said impulsing disc carrying a plunger slideably mounted parallel to said shaft and held against said slipping disc by a spring, said plunger normally engaging a pawl mounted upon said driving disc to effect a coupling between said impulsing disc and driving disc, means for rotating the slipping disc relative to the impulsing disc, said slipping disc including a recess to control movement of said plunger with respect to said driving disc, said movement effective to control said coupling by engaging or disengaging said pawl.

7. In an impulse sending device, circuit controlling impulse springs, an impulsing cam and a masking cam associated therewith individually rotatable within fixed limits upon a single shaft, means for rotating said impulsing cam from either extreme position to the other extreme position, means responsive to a portion of said complete rotation for rotating said masking cam between its extreme positions, said impulsing cam effective to control said impulsing springs during rotation in one direction, said masking cam effective to control said springs during rotation in the opposite direction.

8. In an impulse sending device, impulse springs, off normal springs, an impulsing disc carrying a slipping disc moveable relative thereto Within restricted limits, said discs mounted upon the same shaft with a masking cam which normally disassociates said impulse springs from said impulsing disc, said slipping disc carrying a pro jection to engage said masking cam, means for rotating said impulsing disc in either direction, said slipping disc cooperating with said impulsing disc responsive to a predetermined rotation in one direction to move said masking cam to effect both the association of the impulse springs with the impulsing disc and the operation of the off-normal springs, said slipping disc cooperating with said impulsing disc responsive to a predetermined rotation in the opposite direction to move said masking cam to effect both the disassociation of the impulse springs from the impulsing disc and the release of the off-normal springs.

9. In an emergency impulse sending device, an impulsing cam rotatable within fixed limits and held normally in one extreme position, a single manual starting means, means responsive to one complete operation thereof for effecting the rotation of said cam from its normal position to the other extreme position and its counterrotation to i the normal position, speed controlling means, circuit controlling impulse springs, means for associating said speed controlling means and said impulse springs with said cam during its counter rotation only to send out a predetermined code at a predetermined rate of speed.

CHARLES CLARKE PUCKETTE.

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