US2112375A

US2112375A - Timing mechanism

Info

Publication number: US2112375A
Application number: US68073A
Authority: US
Inventors: Edward D Mead
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1936-03-10
Filing date: 1936-03-10
Publication date: 1938-03-29
Anticipated expiration: 1955-03-29

Description

March 29, 1938. E. D. MEAD 2,112,375

TIMING MECHANISM Filed March 10, 1936 8 Sheets-Sheet l INVENTOR E. D. MEAD A T TORNE V March 29,1938. E, D, MEAD 2,112,375

TIMING MECHANISM Filed March 10, 1936 8 Sheets-Sheet 2 A 7' TOR/VEV E. D. MEAD TIMING MECHANISM March 29, 1938.

1936 8 Sheets-Sheet Filed March 10,

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lNl EN 70/1 E. D. MEAD A T TORNEV March 29, E. D MEA TIMING MECHANISM Filed March 10 8 Sheets lNVENTO/Q E. D. MEAD FIG. /7

ATTORNEY E D. MEAD March 29, 1938.

TIMING MECHAN I$M Filed March 10, I936 8 Sheets-Sheet A T TOPNEV March 29, 1938. E D. D 2,112,375

TIMING MECHANISM Filed March 10, 1936 8 Sheets-Sheet 6 tr/5 MINUTESW 3 M/NUTE$- fez-v5 .V HOLDING Afi con/mar; "H"

m r OFF-NORMAL CONTACTS?" 4 1 CONTACTS m m r 222 GROUND CONTACTS F" A Lock/N6 CONTACTS "a" INVENTOR 0. MEAD BV A 7' TORNEV March 29, 1938. E. D. MEAD 2,112,375

TIMING MECHANISM Filed March 10, 1936 8 Sheets-Sheet 7 INVENTOR By 5.0. MEAD A T TORNEV March 29, 1938. E. D. MEAD 2,112,375

TIMING MECHANISM Filed March 10, 1936 8 Sheets-Sheet 8 .mll. bvw

A 7" Tom/EV Patented Mar. 29, 19 38 a i I UNITED STATES PATENT OFFICE TIMING MECHANISM Edward D. Mead, Caldwell, N. I, assignor to Bell Telephone Laboratories, Incorporated, New

York, N. Y., a corporation of New York Application March 10, 1936, Serial No. 68,073

11 Claims. (Cl. 16119) This invention relates to timing mechanisms form applicable for a telephone connection where and particularly to devices of this character used the charging rate for the initial period differs for measuring intervals of conversation in a telefrom the charging rate for an overtime period of phone system to determine thereby the approthe same duration each. timing unit has one priate charge for the service rendered. The ingear wheel engageable with the constant speed vention is applicable not only to local calls from shaft for measuring the initial period and a secsubscribers' lines or coin box lines where the 0nd gear wheel engageable with said shaft after charges may be uniform for the initial period and the completion of the initial period for measuring each overtime period but is also applicable where any overtime period and for closing the charging the charges depend upon the zone called as well circuit in accordance with the number of revolu- 10 as the duration of the call. tions required to measure the overtime period.

An object of the invention is to simplify and Tensioned spring means may be employed for improve devices used for measuring and indirestoring each wheel to normal after the given eating intervals of time to render them more connection has been broken. Other features of accurate and reliable in their operation and to the invention will appear in the following de- 15 render them capable, with only minor alterations, tailed description.

of assessing charges according to a variety of re- Referring to the drawings: quirements with respect to initial and overtime Fig. 1 is an assembly view of the timing mechcharges. anism for local telephone calls illustrating the The timing mechanism of this invention is pardriving shaft and the manner in which the several ticularly applicable for use with the message regtiming units are mounted; ister circuits disclosed in the copending applica- Fi 2 s a top Vi Of 0116 Of e t ming units; tion of F. J. Scudder Serial No. 68,044, filed March Fig. 3 is a side viewand Fig. 4 an end view 10, 1936, issued as United States Patent 2,089,438 of one of these units;

- on August 10, 1937. Fig. 5 is an end view of the armature hinge of In its preferred form, the invention utilizes a common driving shaft which may be rotated at a 6 is an enlarged e in perspective of an constant speed and a number of electromagnetic arrangement for keep under on t devices having timing elements which are arsion the restoring spring for thu rotatable memgg ranged to be engaged with' and disengaged from her of the timing unit; the driving shaft much in the manner disclosed F g 7 and 8 illustrate the apparatus of 6 in my earlier Patent No. 1,993,793 issued March in difierent positions;

12, 1935. Fig. 9 is an alternative to the apparatus of Each electromagnet has an armature which is actuated when a given telephone connection is Fig. 10 is a diagram illustrating the manner 35 established to move a slidable pinion on the Of pera 0 t e timing unit electrical Contacts driving shaft into engagement with a gear wheel du ing a COHVBISatiOH period being measured of a suitable timing unit. The consequent roy; tation of the gear wheel controls the timing and S- 11 16, inclusive, are Schematic OiMW" charging functions in accordance with the circuit ng illustrating the timing device in its Various 40 requirements. In one form of the invention ap- S a s of Operation; plicable for a telephone connect on where the Fig- 17 is an assembly View Of another yp o charging for the initial period is the same as for timin mechanism for zone calls where the an overtime period of the same duration, the said char in for t e overtime period is on a different gear wheel is adapted to rotate as many revolubas s t a t e initial period; 45 tions as needed to measure a given call, closing Fig. 18 is a top V 19 a S de View and the charging circuit shortly after the beginning Fig. 20 an end view of one of the timin units of of each revolution. A tensioned spring serves to restore the gear wheel to its normal position after Figs. 21 and 22 are bottom views of the timing to the connection has been broken and special unit of Fig. 18; a means are provided for maintaining a substan- Fig. 23 is an "nlarged sectional view of a part tially constant tension on said spring when said of the timing unit of Fig. 18; wheel makes more than one complete revolution Fig. 24 illustrates details of the overtime measin the measurement or a given connection before uring element of Fig. 18; being returned to its normal position. Inanother Figs. 25 and 26 are end view: of the gear 55 wheel of the initial period charging unit of Fig. 18;

Figs. 27 and 23 illustrate details of the restoring spring restraining means;

Fig. 29 is a diagram illustrating the manner of operation of the electrical contacts of the timing unit of Fig. 18 during a conversation period being measured thereby;

Figs. 30 to 3'7, inclusive, are schematic drawings illustrating the timing device of Fig. 18 in its various stages of operation; and

Fig. 38 shows a portion of a machine switching system of the cross-bar type utilizing a local timing unit assembly of the type of Fig. land a zone timing unit assembly of the type of Fig. 17.

A detailed description will first be given of the timing device of Figs. 1 to 16, inclusive. This device (Fig. l) comprises a mounting frame I on which is supported a driving motor 2 and also a shaft 3. The motor 2 is connected to shaft 3 by means of gear wheels 4 and 3. Motor 2 is arranged to be operated at a constant speed so that the rotation of shaft 3 may serve to accurately measure intervals of time. Frame I also supports a plurality of timing elements only two of which are shown as indicated generally by the reference character 3. The driving shaft 3 is I equipped with a series of slidable pinions 1 one for each timing element, and the pinions are keyed to the shaft in the longitudinal groove 3. Each pinion 1 is adapted to be moved into engagement with-the gear wheel forming a part of the corresponding timing element.

The individual timing element, the details of which are shown more particularly in Figs. 2 to 6,

comprises a bracket 3 supported by the main frame I and supporting a fixed shaft l3 on which is rotatably mounted a large gear wheel I I. This gear wheelll is normally disengaged from its driving pinion but when its driving pinion I 'is moved a short distance to the left as viewed in Fig. 1 the teeth of the gear wheel mesh with the teeth l2 on its driving pinion, thereby rotating the wheel II as long as it is in engagement with its pinion.

Gear wheel ii is normally biased to a zero position by a tensioned helical spring l3 which tends to keep a lug l1 on the wheel against a spring stop l3 (Fig. 2), that is, the restoring spring l3 tends to rotate wheel clockwise as viewed in Figs. 3 and 6. Referring more particularly to Fig. 6, one end l3 of this restoring spring is held against a shoulder 23 of a collar 2| fastened to fixed shaft i3. The other end 22 of the helical spring is suitably fastened to the inner face of wheel I I so that the counter-clockwise rotation of wheel (Fig. 6) by its pinion 1 tends to wind up the helical spring as the rotation continues. Attached to wheel II and rotatable therewith is an elongated sleeve 23 surrounding the fixed shaft l3 and acting as a support or, guide for the turns of the spring. The first fewturns of the spring adjacent wheel II are supported on the collar 24 of sleeve 23 while intermediate turns are 51101- mally out of contact with sleeve 23. The outer turns of the helical spring rest on a sleeve 23 formed as a part of stationary collar 2|. The outer end of sleeve 23 freely rotates within the stationary sleeve 23. Located on the outer end of fixed shaft I3 is a nut 23 having an inner shoulder 33 acting as a bearingfor an annular ring-shaped cam 3| having two upwardly extending

projections

32, 33 and an arcuate slot 34 normally containing end l3 of helical spring l3. Cam 3| is driven by a tongue 33 projecting from a bracket 33 fastened to the inner face of the gear wheel II. The purpose of cam 3| is to .maintain a substantially constant tension on helical spring I3 in spite of the number of complete revolutions made by wheel II in timing a given telephone connection as will be explained later. Also mounted on bracket 33 is an annular ring 31 which supports a flexible cam 33 for operating certain electrical contacts to be described later. For the purpose of operating still other electrical contacts there is mounted on the inner face of wheel I a cam 39-.

Each timing unit has an electromagnet 42 best seen in Fig. 3. One end of its armature 43 rests upon the flattened portion 43 of the magnet core and the armature is hinged by two non-magnetic spring strips 44, 43 (Figs. 3 and which are riveted to the corners of the rear end of the armature and are clamped to core portion 43. These

springs

44, 43 are gim an initial bias so that when they are clamped to the core they press the rear end of the armature firmly against the core to avoid magnetic leakage while still affording a knife edge pivot for the armature.

Armature 43 carries a spring member 43 (Fig. 3) having a tongue 41 which rides in the annular groove 43 in its associated pinion 1. When the electromagnet 42 is energized the movement of armature 43 to the left as viewed in Fig. 2 is suiiicient to cause the teethon pinion 1 to engage the teeth on wheel II and start the rotation of wheel II in a counterclockwise direction as viewed in Fig. 3, wheel before engagement with pinion 1 being in a definite zero position as determined by lug |1 against spring stop l3. It is, of course, to be assumed that electromagnet 42 is energized at the moment the called station has answered and that electromagnet.42 is deenergized when the connection is broken so that the amount of rotation of wheel while electromagnet 42 is energized is a measure of the duration of the telephone connection and can be utilized in making the appropriate charges therefor.

The bracket 3 supports a plurality of electrical spring contacts which will be best explained by reference to Figs. 2 and 11 both of which show the gear wheel I I in its normal zero position with lug l1 against spring stop l3. The subsequent Figs. 12 to 16 show the wheel II and its related apparatus in other relative positions. With the electromagnet 42 deenergized its armature 43 is maintained in its outer position by a spring 43 acting against the armature. Spring contact 33 is normally biased to make electrical contact with the stiff contact spring 3|,

contacts

33, 3| being termed the ground contacts D. Spring 33 carries a lug 32 projecting towards the flexible cam 33 carried by the bracket 33 on wheel II but the normal path of movement of cam 33 does not lie in the pathof lug 32. However, armature 43 carries a roller 33 with which the flexible cam 33 will contact when the wheel I I is rotated counterclockwise to throw cam 33 into the path of lug 32 to cause spring 33 to break its contact with member 3| and make contact with the spring 33.

Contacts

33, 33 are termed the charging contacts C.

The spring pile-up also includes two stlf! springs 31 and 33 and two

flexible springs

33, 33. Flexible spring 33 is normally biased to make contact with stiff spring 31 but when the wheel II is in its zero position as in Fig. 11 the cam 33 on wheel presses against a lug 3| mounted on spring 33 to keep electrical spring contacts 31, 33 separated as long as wheel H is in its zero position. Lug 3| also has an' extension 32 which serves to press the flexible spring contact 33 to time.

against spring 60 as long as cam 39 is opposite lug 6|.

Contacts

51, 58 are hereinafter termed the holding contacts A and

contacts

59, 60 the off-normal contacts B. Therefore, with the wheel H in its zero position against stop l8, the holding contacts A are open, theoil-normal contacts B are closed, the charge contacts C are open and the ground contacts D are closed. The functions of these contacts will be described briefly later but for a more detailed description reference is made to the Scudder application mentioned above. 4 v

When the electromagnet 42 is energized its armature 43 acting against retracting spring 49 brings pinion 1 into engagement with the gear wheel H and also by means of roller 55 bends flexible cam 38 into the path of lug 52 on spring 50. The armature is shown in its actuated position in Fig. 12 whereupon the gear wheel H starts turning in the direction indicated by the arrow. Shortly after the turning movement has started, cam 39 rides 01f lug 6| and flexible spring 58 is then free to follow its natural bias to close holding contacts A and open the off-normal contacts B as shown in Fig, 13. Contacts A remain closed and contacts B remain openuntil cam 39 has again reached lug 6 I. Shortly after the holding contacts A have been closed the flexible cam 38 contacts momentarily with lug 52 to open the ground contacts D and close the charging con tacts C as shown in Fig. 14. As soon as lug 52 becomes free of flexible cam 38 the flexible spring 5!] follows its natural bias to open the charging contacts C and close the ground contacts D as shown in Fig. 15. The condition of the contacts shown in Fig. 15 holds during the greater part of acomplete revolution of wheel ll. Fig. 16 shows the condition just before wheel l i has finished a complete revolution and one complete revolution will have taken place as soon as wheel I I has moved far enough from its position of Fig. 16 to allow spring stop it to drop behind the rear edge of lug [1. It will be apparent from Fig. 16 that just prior to the completion of one revolution of wheel ll, lug 6i rides up on cam 39 to again open holding contacts A and close onnormal contacts B.

It will be apparent that gear wheel ll may make only a partial revolution or as many complete revolutions as are needed for timing the particular telephone connection for which the timing unit has been selected. If the telephone connectionelasts for a time corresponding to less than one complete revolution of wheel ll it will be apparent that the charging contacts C will be operated only once but if the telephone connection continues for a fraction of an additional turn of wheel H the charging contacts will again be actuated as it will be seen from Fig. 16 that only a small additional movement of flexible contact'38 is needed to cause the second closing of the charging contacts C,

The diagram of Fig. 10 illustrates the manner in which the contacts are operated with respect In Fig. 10 it is assumed that the time required for a complete revolution of wheel H is five minutes and that the charging contacts are to be operated once for each five-minute period or fraction thereof. The two vertical lines Si and 58 are intended to represent the duration of a five-minute period where vertical line 61 represents the beginning of the period with wheel I l. in zero position, and vertical line 38 represents the end of the five-minute period with the wheel having completed exactly one revolution.

Lines

63, 64, 65 and 56 represent the condition during the measured period of the holding contacts A, the off-normal contacts B, the charging contacts C and the ground contacts D, respectively. It will be seen that shortly after the beginning of the measured period the holding contacts are closed and the oif-normal contacts are opened and they continue in their altered position until just prior to the elapse of the five-minute period when the holding contacts are opened and the off-norn1al contacts closed. At the beginning of the initial period and shortly after the holding contacts and off-normal contacts are operated the charging contacts C are momentarily closed, accompanied by the momentary opening of the ground con tacts D. If the measured period extends beyond the initial five-minute period it will be obvious that the contacts again are operated in the same manner as at the beginning of the initial period.

As previously stated, the timing unit of this L invention as above described contemplates having gear wheel ll make one complete revolution for the initial period of a conversation being measured and to have the wheel make as many additional revolutions or fractions thereof as are needed to measure the overtime period. It is, therefore, necessary to provide means for preventing the restoring spring l6 from becoming wound too tightly. Preferably, automatic means are provided for unwinding the helical spring l6 one turn whenever the wheel II by its rotation has wound the spring up substantially one turn. A preferred arrangement is disclosed in Figs. 6, '7 and 8. As previously described, with reference to Fig. 6, one end of helical spring is fastened to 1.

wheel ii and the other end lics against the sta tionary stop 20 so that as the wheel ll revolves counter-clockwise the spring is wound up. The normal position for driving tongue 35 with the wheel in zero position is adjacent shoulder 32 of cam ring 3i as shown in Fig. 3. Fig. 6 shows wheel it after it has been rotated about 90 degrees from its normal position as indicated in that figure by the angular relation of spring stop 98 to lug ll. volving counter-clockwise under the action of pinion l tongue 35 moves with the wheel and after the wheel has moved about 90 degrees as shown in Fig. 6 the tongue 35 contacts with shoulder 33 and rotates cam ring 3| along with the wheel. Tongue'35 continues to drive cam ring 3i counter-clockwise and finally reaches the position shown in Fig. 7 where the wheel has completed one revolution and has also turned through a small fraction of another revolution. At this position of big. 7 cam surface ll contacts with end iii of the helical spring and with the further counter-clockwise movement of cam ring 3! as shown in Fig. 8 raises the spring end i9 over the top of stationary stop 29 thereby freeing that end of the spring and alldwing it to start unwinding. However, spring end [9 in flying around the nut 29 enters slot 36 in the cam ring and pushes cam ring 3| forwardly until the spring end again comes to rest against stop 20. The spring, therefore, unwinds only one turn at a time and will not unwind another turn until the wheel II has completed another revolution from its position in Fig. 8. If the wheel H is disengaged from its driving pinion 7 prior to the completion of its first revolution it will be obvious that whatever winding-up of spring l6 took place will be annulled by the clockwise restoring movement of the wheel. If we assume that the wheel I1 is disconnected from its driving pinion when When the wheel ll starts refrom its zero position through an angle indicatedby the difference in the positions of shoulder 33 in Figs. '7 and 8. In order that this unwinding mechanism may be effective without impairing.

the main function of the spring to supply a restoring force to return the wheel I I to its normal position, a lost motion connection between driving tongue 35 and cam ring 3| is desirable. The arcuate slot 34 should'extend far enough towards shoulder 33 that there will be no danger when tongue 35 is against shoulder 32 that spring end l3 will contact with the closed end of slot 34 instead of stop 28.

An alternative form of the unwinding mechanism for the helical spring is shown in Fig. 9. The portion of a timing unit shown in Fig. 9 is identical with that disclosed in the earlier figures except for the unwinding mechanism. The gear wheel 1 is shown turned substantially 90 degrees counter-clockwise from its zero position which is determined by having lug 16 against spring stop 11. Wheel 15 is suitably mounted for rotation about a fixed shaft 18 and the wheel 15 carries a drum 18 about which is wrapped the helical restoring spring 88 one end of which is fastened to wheel 15 and the other end 8i passes over a stationary nut 82 and is held against a shoulder 83 on said nut. The outer end of drum 1!! is cut away to form a bearing for a cam ring 84 which has a cam surface 85 and an arcuate shaped arm 88 above an elongated slot 81. The outer edge of drum 19 which is of reduced diameter to support the cam ring 84 also has a radial wedge-shaped slot defined by shoulders 88 and 98 therein into which fits loosely a projection 89 from the inner side of the cam ring 84. With wheel 15 in its zero position, projection 88 is normally adjacent shoulder 98. As the wheel begins rotating counter-clockwise, projection 88 advances until it strikes shoulder 88 and thereafter the cam ring is rotated with the wheel 15, which rotation, if continued more than a complete revolution, will cause cam surface 85 to contact with spring end 8| and raise the end of the spring over the top of stop 83 thereby allowing the spring to unwind one turn in the same manner as described for Fig. 6. The main difference between Figs. 6 and 9 is in the manner of actu- Ming the cam which temporarily frees the spring end from its retaining stop. Further description of Fig. 9 is, therefore, believed unnecessary.

A detailed description will now be given of an alternative form of the timing mechanism disclosed in Figs. 1'1 to 3'1. The timing mechanism of these figures is particularly designed for use in operating message registers where the charge for and the duration of each overtime period may be different from the charge for and duration of the initial period.

The assemblyof these timing devices for zone calls comprises, as shown in Fig. 17, a mounting frame I88 on which is supported a constant speed driving motor IN and a shaft I82 connected therewith by suitable gearing. Frame I88 also supports a plurality'of timing units only two of which are shown indicated generally by the reference character I83. The driving shaft I82 ad- Jacent each timing unit is equipped with two slidable pinions I84, I88 keyed to the shaft in the longitudinal groove I88. The pinions I84 and I85 are adapted to be selectively engaged with gear wheels individual to each timing unit.

The individual zone timing unit the details of.

which are shown more clearly in Figs. 18 to 28 comprises an L-shaped bracket I81 fastened to the main frame I88, said bracket supporting a fixed hollow shaft I88 (Fig. 23) on which is rotatably mounted a large gear wheel I83. This gear wheel I88 is normally disengaged from its driving pinion I84 but when its driving pinion is moved by means hereinafterdescribed, the teeth of gear wheel I88 mesh with teeth II8 on driving pinion I84 thereby rotating wheel I88 until their engagement is broken. Gear wheel I89 is utilized for timing the initial period while another gear wheel H3 is employed for timing any overtime period. Means hereinafter described are provided responsive to the substantial completion of a revolution by wheel I88 for moving pinion I85 so that its teeth mesh with the teeth of gear wheel I I3 whereby wheel I I3 may be rotated as many revolutions as required to measure the length of the overtime period.

Referring more particularly to Fig. 23, the overtime wheel Il3 is fastened to a shaft II4 which is rotatably mounted within the fixed hollow shaft I88 and projects beyond it at both ends. The initial wheel I88 does not bear directly on fixed shaft I88 but is 'fastened to one end of an elongated sleeve II5 which is rotatable about shaft I88. Around sleeve I I5 is a helical restoring spring I I6 one end I I1 of which (Figs. 23, 24) is anchored by insertion in a hole in a rotatable annular disc II8 fastened on sleeve H5, and therefore, rotatable therewith. Disc II8 may have projecting lugs II9 (Fig. 24) which fit into slots I28 in. the end of sleeve iii, the disc II8 being held in place by a threaded collar Hi. The other end I22 of helical spring H8 is held stationary by passing through a hole in stationary arm I23 (Fig. 21). The rotatable sleeve H5 is held in place by a nut I24 threaded on the end of stationary shaft I88 the opposite end of sleeve II5 bearing against shoulder I25.

The rotatable shaft H4 at one end carries the overtime wheel I I3 and its other end has fastened thereto a sleeve I28 which extends beyond the end of shaft II4. Aligned with the axis of shaft II4 but supported independently thereof is a stationary pin I21 fastened to a mounting bracket I28. On stationary pin I21 is mounted a sleeve I3I the open end of which overlaps the adjacent end of rotatable sleeve I26. Sleeve I3I is held in place by a threaded nut I32 having a portion of reduced diameter which acts as a bearing for a cam member I33. Rotatable sleeve I28 and stationary sleeve I3I act as supports for the tensioned helical spring I34 used for biasing the overtime gear wheel 3 to its normal position. One end I35 of the spring is anchored in a hole in a cam member I38 mounted on rotatable sleeve I26 while its other end I31 (Fig. 20.) normally lies against a shoulder I38 on sleeve I3I (similar to shoulder 28 of Fig. '7).

Since gear wheel H3 is adapted to rotate any desired number of revolutions it, therefore, is necessary to provide means for preventing its restoring spring I34 from becoming wound too tightly and the means provided is essentially the same as that of Figs. 6, '1 and 8 in that the spring is allowed to unwind one turn every time gear 'agailzst stop I54 (Fig. 20).

7 hit against stop I54, the teeth which rides in groove I68 in pinion I05.

wheel I I3 rotates slightly more than one complete revolution. Fastened to bracket I36 isa laterally extending arm I39 which extends between two spaced upwardly extending shoulders I40, I4I

(Fig. 19) on cam ring I33 so that the rotation of bracket I36 also rotates camring I33. This insures that cam surface I42 of cam ring I33 once each revolution will serve to lift spring end I31 over shoulder I38 to permit the spring to unwind one turn as previously described with respect to Figs. 6, 'l and 8.

The unwinding arrangement for spring I34 differs in one respect from that of Figs. 6, 7 and 8 in that a thin metal collar I45 (Figs. 27, 28) is inserted between stationary sleeve I3I and the last few turns of the spring. This sleeve I45 has an upturned edge I46 with a slot I41 into which fits the end I31 of the restoring spring. When cam surface I42 lifts spring end I31 over shoulder I38 the spring end is still retained in slot I41 so that collar I45 rides around with the spring end in the unwinding process. Collar I45 serves to reduce the velocity with which end I31 travels around nut I32 and. hence reduces the danger that end I31 will 'be broken by the force with which it hits against shoulder I38.

Each timing unit I03 has an .electromagnet I48 (Fig. 19) which is energized over suitable circuits when the telephone connection is established the duration of which is to be measured by the timing unit. Its armature I49 has a spring extension I50 which ridesin a groove in pinion I04 so that the attraction of armature I49 moves pinion I04 into engagement with initial timing wheel I09. Restoring spring II6 normally holds initial wheel I09 in its zero position with lug I53 Pinion I04 causes the counter-clockwise rotation of initial wheel I09 as viewed from the right in Fig. 18. Wheel I09 being used for timing only the initial period, is adapted to make only one revolution. Just prior to the time that in the counter-clockwise movement of wheel I09,-lug I53 would again on pinion I04 encounter a toothless portion I55 on the wheel periphery (Fig. 26) so that the driving pinion is no longer effective. This toothless portion,

' however, is bridged by teeth I56 on a separate plate I51 attached to the wheel, teeth I58 being displaced far enough from the main teeth on wheel I09 that they are not engaged by pinion I04 but are engaged by the gear I58 attached to the speed governor I59 (Fig. 18). The initial timing wheel I09, therefore, ceases rotation as soon as pinion I04 reaches this toothless region at. which time wheel I09 has completed substantially one revolution.

Just prior to the completion of the rotation of initial wheel I09 the initial wheel sets into rotation the overtime wheel H3 in the following manner providing, of course, that the conversation to be measured is still continuing. Initial wheel I09 carries a lug I62 (Fig. 22) which just prior to pinion I04 reaching toothless segment I55, contacts with a roller I63 carried byan' arm I64 hinged to frame I 01 by a spring member I65 which normally biases roller I63 towards wheel I09 against a stop I66 which is an extension of frame I01 (Figs. 21 and 22). An extension of spring member I85 carries an extension I61 The free end of spring I65 is normally biased against an angle piece I69'formed from arm I64. when cam I62 comes into contact with roller I63 the consequent movement of arm I64 serves to bring teeth I on pinion I05 into engagement with the teeth on gear wheel H3 and start its rotation. Overtime wheel H3 is normally biased to its zero position with lug I1I against spring stop I12 (Fig. 21) due to its restoring helical spring I34. Wheel I I3 will now begin rotating to measure the overtime period of the telephone connection and will continue rotating as many complete revolutions as are needed. During the movement of wheel II3 spring I34 will unwind one turn for each complete revolution of the wheel in the same manner as described in connection with Figs. 6 to 8.

Certain electrical contacts are controlled by initial wheel I09 and overtimewheel H3 and the operation of these contacts will now be described with special reference to Figs. 30 to 3'1.

contact spring I89 to contact with the stiff contact spring I90. Spring I90 is biased to press on stud I81 and normally maintain an extension of spring I81 against a stationary stop I9I. This arrangement normally maintains open the charging contacts I81, I89 hereinafter called E and normally maintains closed the ground contacts I90, I89 hereinafter called F. Intermediate spring I v89 carries angle piece I92 adapted to be moved into the path of the toothed charging cam I93 driven by initial wheel I09 and into the path of the toothed charging cam I94 driven by overtime wheel II3.

The stiff contact spring I95 is normally biased against a stationary stop I96 and stiff contact spring I91 is normally biased against stud I85 carried by the armature to bias the armature to its non-operated position. Hence the attraction of .armature I49 serves to close contacts I95, I91 hereinafter called locking contacts G. Spring I98 is not an electrical contact spring and its purpose will be described later, but it may be noted that spring I98 is normally biased against stop I86 carried by the armature. Contact spring 200 carries a stud I which passes through an aperture in contact spring 203 and is pressed against cam 202 mounted on initial wheel I09 so that theholding contacts H between

springs

200, 203 will be closed as soon as cam 202 has moved away from stud 20I. Stiff contact spring I99 is also biased towards wheel I09 but is restrained by spring projection 204 acting against stud 20I. Contact spring 205 has a stud 206 which normally rests on cam 201 mounted on wheel H3 and spring 205 has a second stud 208 which passes through apertures in springs I99,

closed the off-normal 205 ispressed against tacts I closed. when the timing unit is seized for the measurement of the duration of an established telephone connection the electromagnet I49 is energized to attract its armature I49 as shown in Fig. 31. Armature I 49 when attracted closes the locking contacts G due to the movement to the left of stud I99 carried by the armature. Stud I94, also carried by the armature, contacts with projection H9 and serves to move the three contact springs I91, I99, I99 to the left to bring projection I92 into the path of the toothed cams I99, I94 while still preserving the ground contacts F closed and the charge b'dntacts E open. The attraction of armature I49 also brings pinion I94 into engagement with initial wheel I99 which starts rotating in the direction indicated by the arrow.

Shortly after initial wheel I99 starts turning, cam 292 rides oil stud 29I, allowing the biased spring I99 to move to the right to open the onnormal contacts I and close the holding contacts H as shown in Fig. 32. Cam I99 which is mounted on disc I I9 and which, therefore, rotates with wheel I99 now comes into contact with projection I92 (Fig. 33) and hence moves spring I99 to the right once for each tooth 2| I on the rotating cam I99. This movement serves to temporarily close the charging contacts E and term porarily open the ground contacts F and in the particular timing unit disclosed it will be seen that the charging contacts will thus be closed six times, it being assumed that for the particu lar call being measured the calling station's message register should be operated six times as the appropriate charge for the initial period.

Just prior to the time that pinion I94 reaches the toothless segment on wheel I99 cam 2 I2 comes into contact with spring I99 and spring I99 is pressed to the right by the front sloping edge of cam 2I2. The arrangement is such that at the moment pinion I94 reaches toothless segment I99 of wheel I99 cam 2I2 has caused the maximum movement to the right of spring I99 and the spring is starting to ride down the rear sloping edge 2I9 of the cam. The pressure of spring I99 on cam- 2I2 is sumcient to move wheel I99 slightly forward as spring I99 slides down slope 2I9 to positively separate the teeth on pinion I94 from the'last tooth on wheel I99. That is, spring I99 serves to keep wheel I99 in the position shown in Fig. 26. Fig. 34 shows wheel I99 in its maximum advanced position where it will remain until the magnet I49 is deenergized. Just prior to pinion I 94 reaching toothless segment I99 earn 292 again contacts with stud Hi to close the off-normal contacts I and open the holding contacts H as shown in Fig. 34. Also just prior to the completion of the movement of wheel I99 lug I92 on wheel I 99 (Figs. 20, 22) comes into contact with roller I99 to cause' projection I91 to move pinion I99 into engagement with overtime wheel II9. as previously described. Fig. 34, therefore. shows the overtime wheel II9 about to egin its movement.

As the rotation of wheel II9 begins (Fig. 35) cam 291 moves. of! stud 299 to open the oi!- nornml contacts I and close the holding contacts H in a manner previously described. Since electromagnet I49 is still energized, projection I92 is still in the path of the toothed cam I94 which "as shown in Fig. 23, is a portion of member I99 and hence rotatable with wheel I I9. After wheel II9 has moved an appreciable distance the toothed cam I94 (Fig. 36) serves to momentarily open the ground contacts 1" times and momentarily close the charging contacts E three times since there are three teeth on cam. I94. This means that for each complete revolution of wheel H9 or fraction of a revolution the calling station's message register will be operated three times, it being assumed that such is the appropriate charge for each overtime period.

As overtime wheel I I9 nears the completion of a revolution as shown in Fig. 37 stud 299 is moved to the rightby cam 291 to momentarily close the off-normal contacts I and momentarily open the holding contacts H, but as soon as cam 291 has passed and the wheel II9 has started on its next revolution the off-normal contacts I will again "be opened and the holding contacts H again be closed until stud 299 again encounters cam 291.

When electromagnet I 49 is deenergized restoring spring II9 will restore initial wheel I99 to its zero position with lug I94 against stop I99 and spring I34 will restore overtime wheel II9 to its zero position with lug I1I against spring stop I12 as shown in Fig. 30. The retraction of armature I49 withdraws pinion I94 and pulls spring I99 out of .the path of cam 2I2 to allow restoring spring ll9'to restore wheel I99, while the restoring movement of wheel I99 causes cam I92 to-ride of! roller I99 (Figs. 21. 23) and permits the spring pressed member I94 to disengage pinion I 99 from wheel I I9.

In the preferred form of the invention, motor 2 of the local time unit assembly is continuously operated while motor I9I for the zone timing unit assembly is normally idle and operated only when one of its associated timing units is seized but it will be apparent that both motors may be normally idle or normally rotating if desired.

A suitable speed governor is provided for controlling theretum speed of each gear wheel. Governor I99 which engages initial wheel I has already been referred to while a similar governor 229 is provided for overtime wheel II9.

In the particular example of zone timing unit chosen for illustration it has been assumed that the initial period was five minutes for which the message register would be operated six times, and that the duration of each overtime period was three minutes, for which the message register' would be operated three times. It will be noted mm Fig. 17 that gear I19 on pinion I99 is larger than gear II9 on pinion I94 and that overtime wheel I I9 is smaller than initial wheel I99, the relation being such that initial wheel I99 makes a complete revolution in five minutes while overtime wheel II9 makes a complete revolution in three minutes.

- Fig. 29 graphically represents the condition of the various contacts during the initial and first overtime period for the zone timing unit. Line 22I shows that the locking contacts G are closed at the instant the armature I49 is attracted at the beginning of the initial period and that the locking contacts are not broken in going from the initial period to the overtime period. Line 229 shows that the holding contacts E are closed shortly after initial wheel I99 starts rotating. are opened shortly before wheel I99 stops rotating and are closed again'shortly after overtime wheel II9 starts rotating. Line 224 shows that the oi!- normal contacts I are opened shortly after the initial wheel I99 starts rotating, are closed shortly before wheel I99 ceases rotating and are opened again shortiy=after overtime wheel 9 starts rotating. Line 222 shows that the ground contacts F are closed except when the charging contacts E are operated. Line 229 shows that the 79 charging contacts E are operated shortlyafter the holding and oif-normal contacts have been operated, to operate six times the message register associated therewith, and that shortly after the beginning of each overtime period the charging contacts are closed three times.

In the disclosed zone timer it has been assumed that gears I10 and H3 are so designed with respect to the speed of shaft I02, that wheel H3 completes a revolution once every three minutes and that gears I09 and H are so designed that the revolution of wheel I09 takes five 'minutes. These gear combinations, however, may be readily altered to give any desired initial period or overtime period for other zone timing mechanisms which may be required to charge for calls to the various zones to which the calling subscribers line may be extended. It is also obvious that other zone timing mechanisms may have any desired number of teeth on the initial period charging segment I93 and the overtime charging segment I94.

Fig. 38 is intended to illustrate certain of the circuits and circuit connections involved in a cross-bar machine switching system in the selection of the proper timing unit for timing aparticular telephone connection. The complete circuits are not disclosed but are shown in greater detail in the above-mentioned Scudder application.

It will first be assumed that the dialed call is between exchanges within the local area. The calling subscribers station 230 will be connected through the primary and secondary switches of the line switch through a district trunk and the district primary and secondary switches to the called subscribers station 23I. The district trunk relay 238 will be energized in the usual manner. The dialed information sent to the decoder marker 232 causes it to connect ground to conductor 235 thereby energizing relay 234 providing the local timing unit associated with the selected district trunk is in its normal position with its off-normal contacts B closed. The energization of relay 234 takes place over a circuit from battery, winding of relay 234, conductor 260, closed contacts B, conductor 235, to ground 236. Relay 234, therefore, pulls up its contacts and is locked up over a circuit from battery, winding 234, left inner front contact relay 234,

- conductor 242, contact relay 238 to ground.

When the called party answers, the called station supervisory relay 231 is energized and after a certain delay indicated by the dotted character of conductor 240 a circuit is established for starting the operation of the local timing unit associated with the particular district trunk circuit employed in. establishing the connection. This circuit may be traced from battery, windingrelay magnet 42, conductors 239, 2, left middle front contact relay 234, conductor 24d, and front contact relay 231 to ground. Magnet 42 pulls the pinion 1- into engagement with gear wheel I I' and the local timing unit begins to function to measure the duration of the connection.

between stations 230 and 23L Motor 2 which drives pinion 1 is constantly operating as shown in the figure.

Gear wheel II in rotatmg will first open the off-normal contacts B and close the holding contacts A and shortly thereafter will open ground contacts D andamomentarily close charging con- Contacts A in closing establish a holding circuit for relay magnet 42 which may be traced 75 from battery, winding relay 42, conductor 239,

closed contacts A, conductor 280, left inner front contact'relay 234, conductor 242, front contact district trunk relay 238 to ground.

With relay 234 energized the normally closed ground contacts D are connected through conductor 243, left outer front contact relay 234, conductor 244 over the lowest contacts of the primary and secondary line switch cross-points, winding message register relay 245, thereby short-circuiting the message register to prevent its false operation as long. as the ground contacts D are closed. When wheel II has opened ground contacts D and momentarily closed charging contacts C, it will beobvious that the message register relay 245 will be operated.

Whenever the calling subscriber places his receiver back on the switch-hook, relay 238 releases, in turn releasing relay 234 which opens the operating and holding circuits for relay magnet 42. The gear wheel II will thereupon be restored to normal by its restoring spring as previously described.

Itwill' now be assumed that the call initiated by the calling station 230 is to a station served by an exchange located outside the local area. The

connections between the calling subscribers district trunk and the decoder marker are established in the manner described in the above-mentioned Scudder application. The marker 232 knowing the oflice code information transmitted to it by the sender (not shown) operates one of its zone relays such as relay 246, the particular zone relay operating being dependent upon the zone in which the called station exchange is lo cated. It will be assumed that shaft I02 is adapted to operate only one at a time the several zone timing units associated therewith, each timing unit being adapted to serve for a different zone, it further being assumed that there are a number of such shafts H12 available for selection, each shaft controlling its respective zone timing units. The decoder marker acting under the dialed oflice code designation supplied to it controls apparatus (disclosed in the Scudder application) which tests for a zone timing unit assembly which has all of its timing units idle as indicated by the fact that all of the off-normal contacts of its timing units are closed. It will be noted that conductor. 241 is connected to battery through the closed off-normal contacts of all of the timing units associated with the disclosed zone assembly. Consequently when a test relay (not shown) is operated when connected to conductor 247 it is indicated that the particular zone assembly under test is idle and hence available for timing the call. The marker, therefore, connects ground to that relay magnet of the zone assembly which is associated with a timing unit having the proper charging rate for the called zone. Thus, it may be assumed that the timing unit associated with relay magnet I48 is the desired unit and vhence the marker connects ground to conductor 248 leading to winding relay 548, battery and ground, causing relay I48 to operate. In the meantime the district trunk relay 238 has operated but the marker does not operate its local relay 249 and hence for a zone call relay 234 is left unoperated. Also under control of .the marker the cross-bar switch mechanism 258 is operated to connect

conductors

25I, 252 and 253 to the selected idle zone assembly as will now be described.

Relay magnet I48 when operated serves to engage pinion I 04 with the initial wheel I 09 but shaft I02 is normally idle. Relay magnet I48 in operating locks up over a circuit from battery, winding relay I48, locking contacts G,

conductors

255, 256, switch 250 and conductor 25I to ground. As soon as the called party 23I answers, the called station supervisory relay 231 is operated and starts the motor IIII by closing the following circuit from battery, motor IIlI, conductor 2,54, switch 250, conductor 253, left middle back contact relay 234, conductor 24!! and front contact relay'23'l to ground. Motor IIII, therefore, starts rotating shaft I02 and hence the initial wheel I09 starts rotating to measure the initial time interval. The movement of wheel I09 first opens the off-normal contacts I so that no other trunk circuit may seize a timing unit driven by motor I0 I and also closes the holding contacts H to establish a holding circuit for motor IIII from battery, motor IllI,

conductors

254, 251, closed contacts H, conductor 256, switch 250 and conductor 25I to ground.

It will also be noted that switch 250 serves to connect the ground contacts F to the message register 245 over a circuit which may be traced from ground, closed contacts F, conductor 258, switch 250, conductor 252, left outer back contact relay 234, and the primary and secondary line switches to the winding of the message register relay 245. The continued movement of wheel I09 and cam I93 will open ground contacts F and close the charging contacts E to connect battery to the message register. relay a number of times, depending upon the number of teeth on cam I 93. After wheel I09 has made substantially a complete revolution corresponding to the end of the initial period, wheel I09 causes overtime wheel I I3 and cam I94 to start rotating for measuring the overtime interval. Wheel H3 will also operate the charging contacts E a number of times depending upon the number of teeth on cam I94 as previously described, thereby operating the message register 245 in accordance with the proper charges for eachovertime interval.

When the calling party 230 hangs up, therelease of relay 239 serves to open the energizing circuits for motor IIII and relay magnet I48 whereupon the timing wheels I09 and H3 restore to their normal positions under the action of their restoring springs and are, therefore, ready to be selected for another call.

For convenience in simplifying the schematic showing of the zone timing unit of Fig. 38 one set of ground and charging contacts have been shown for the initial wheel and another set of ground and charging contacts have been shown for the overtime wheel, but it is to be understood as described in connection with the earlier figures that the preferred arrangement is such that the initial and overtime wheels actuate the same set of charging and ground contacts. For purposes of simplification there is also omitted from Fig. 38 the manner in which the overtime wheel I I3 controls the holding contacts H and ofi-normal contacts I as explained in connection withFigs. 30 to 37.

What is claimed is:

1. A timing device comprising a driving member, a rotatable driven member normally disengaged from said driving member, an electromagnet having an armature which when attracted controls the engagement of one of said members with the other of said members, electrical contacts operated by the advance ofsaid driven member from its normal position, .a tensioned helical spring for restoring said driven member to its normal position after disengagement from said driving member, a stationary shoulder normally engaging one end of said spring, the other end of said spring rotating with the rotation of said driven member tending to wind up said spring as said driven member rotates, a cam member driven by said driven member for periodically releasing said first spring end from said shoulder to cause said released end to make a revolution before coming again to rest against said shoulder.

2. A timing device comprising a driving member, a rotatable driven member normallydisengaged from said driving member, an electromagnet having an armature which when attracted controls the engagement of one of said members with the other of said members, electrical contacts operated by the advance of said driven member from its normal position, a tensioned helical spring for restoring said driven member to its normal position after disengagement from said driving member, a stationary cylindrical surface on which one end of said spring rests, the other end of said spring rotating with said driven member, a stationary shoulder acting as a stop for said first end to hold said spring under tension, a cam member driven by said driven member for periodically releasing said first spring end from said shoulder to permit said first end to complete a revolution about said cylinder before again coming to rest against said shoulder.

3. A timing device comprising a driving member, a rotatable driven member normally disengaged from said driving member, an electromagnet having an armature which when attracted controls the engagement of one of said members with the otherof said members, electrical contacts operated'by the advance of said driven member from its normal position, a tensioned helical spring for restoring said driven member to its normal position after disengagement from said driving member, a stationary cylindrical surface on which one end of said spring rests, the other end of said spring rotating with said driven member, a stationary shoulder acting as a stop for said first end to hold said spring under tension, a rotatable cam member for periodically releasing said spring end from said shoulder to permit said one end to complete a revolution about said cylinder before again coming to rest against said shoulder, means rotatable with said wheel for rotating said cam, said means being disengaged from said cam when said driven member is in its normal position.

4. A timing device comprising a driving member, a rotatable driven member normally disengaged from said driving member, an electromagnet having an armature which when attracted controls the engagement of one of said members with the other of said members, electrical contacts operated by the advance of said driven member from its normal position, a tensioned helical spring for restoring said driven member to its normal position after disengagement from said driving member, a stationary cylindrical surface on which one end of said spring rests, the other end of said spring rotating with said driven member, a stationary shoulder acting as a stop for said first end to hold said spring under tension. a rotatable cam member for periodically releasing said spring end from said shoulder to permit said one end to complete a revolution about said cylinder before again coming to rest against said shoulder, means rotatable with said wheel for rotating said cam, said cam member having an elongated arcuate slot for guiding the trical contacts actuated by the advance of said wheel from its normal position, a spring stop for determining the normal position of said wheel, means rotatable with said wheel normally engaging said stop, a tensioned helical spring for restoring said wheel to its normal position against said stop after the disengagement oi said driving member and said wheel, a stationary cylindrical surface aligned with said axis and on which one end of said spring rests, the other end oi said spring being rotatable with said wheel, a sleeve mounted on said wheel for supporting a plurality oi the turns of said spring, a stationary shoulder normally engaged by said first spring end to hold raid spring undertension, a cam member rotst= able about said axis, said cam member having spaced shoulders, a projection rotatable said wheel and located between said spacedshoulders, said projection driving said cam member after said wheel has been moved a substantial distance from its normal position, said cam member after making a substantially complete revolution on said first spring end to release said first spring end from said shoulder to permit said springable driven memberfelectromagnetlc means for moving one of said members into engagement with the other of said members to cause salt driven member to be rotated through a definite angle but not beyond said angle, electrical contacts for controlling a subscribers charging cir cult, said contacts being actuatedby said driven member when advanced from its normal position, a second rotatable driven member, means under the control of said first driven member for rotate ing said second driven member after said first driven member has advanced to a definite position, said second driven member during its rotation also actuating said contacts.

7-. A timing device for measuring the duration 01' a telephone connection for which the subscriber is charged at a certain rate for a given initial period or any fraction thereof and is charged at a diflerent rate for an overtime period, said device comprising a driving member, a rotatable driven member, electromagnetic means for for rotating-the same but normally disengaged therefrom, cam means rotatable withsaid driven member for actuatmc said means to rotation oi said second driven member after said first driven member has reached a definite advanced position, and means controlled by said second driven member for controlling said contacts.

8. A timing device for measuring the duration of a telephone connection comprising a rotatable shaft, slidable pinions on said shaft, a rotatable wheel, electromagnetic means for moving one oi said pinions into engagement with said wheel, a second rotatable wheel, cam means rotatable with said first wheel-for actuating a second of said pinions to move said second pinion into engagement with said second wheel when said first wheel has reached a definite advanced position, electrical contacts controlled by said wheels and means for restoring each or said wheels to a definite normal position when said electromagnetic means has disengaged said first wheel from said first pinion" A timing device for measuring the duration or? a telephone connection comprising a rotatable slidable pinions on said shalt, a rotatable toothed gear wheel, electromagnetic means -for moving one oi said pinions into engagement with wheel, said wheel having a toothless segment to render said pinion inefiective alter said wheel has been advanced to a definite no time, a second gear wheel, means controlled by the adoi said first wheel for causing a second pinion to engage said second wheel, electrical concontrolled by said wheels and means for restoring each oi said wheels to a definite normal position when said electromagnetic means has disengaged said first pinion from said first wheel.

ii). device for measuring the duration on? a telephone conversation comprising n rotatable shalt, gears driven by said shaft, a rotatable driven: member comprising a gear wheel, electromagnetic means for engaging said wheel with one of said gears, said wheel having a toothless segment to render first gear ineffective after said wheel has been advanced to a definite position, spring means for preventing contact between the teeth on said wheel and the teeth on said first gear when said first gear reaches said toothless segment, a second rotatable driven member comprising a second gear wheel, means controlled by said first member for engaging said second scriber is charged at a certain rate for a given initial period 1 any fraction thereof and is charged at a certain rate for an overtime period,

, said device comprising a drivingmember, a rotatable driven member for measuring said initial period, a. rotatable driven member tor measuring said overtime period. electromagnetic means 101 en a ing said driving member and said initial member, means for disengaging said driving memand said initial member after said initial member has rotated for a time interval substantially equal to said initial period, means controlled by said initial member andeflective only after said initial member has advanced sumciently to substantially complete the measure ment of said initial period tor ensaflne said driving member and said overtime member, said initial member and said overtime member each ing member from their normal positions, and being biased to a deiinite normal position, elecmeans eii'ective alter the disensagement 0! said trical contacts for controlling a subscriber's driving member and initial member for holding charging circuit and actuated both by said initial said initial member in its advanced position durmember and said overtime member when said ing the time interval said driving member is in 5 initial member and said overtime member are engagement with said overtime member.

advanced a predetermined amount by said drlv- EDWARD D. MEAD.