US2557638A - Telecommunication system - Google Patents

Telecommunication system Download PDF

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Publication number
US2557638A
US2557638A US11403A US1140348A US2557638A US 2557638 A US2557638 A US 2557638A US 11403 A US11403 A US 11403A US 1140348 A US1140348 A US 1140348A US 2557638 A US2557638 A US 2557638A
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Prior art keywords
test
relay
selector
switch
circuit
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Expired - Lifetime
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US11403A
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English (en)
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Hertog Martinus Den
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International Standard Electric Corp
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International Standard Electric Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H67/00—Electrically-operated selector switches
    • H01H67/02—Multi-position wiper switches
    • H01H67/04—Multi-position wiper switches having wipers movable only in one direction for purpose of selection
    • H01H67/06—Rotary switches, i.e. having angularly movable wipers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/42—Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker

Definitions

  • the present invention relates to automatic or semi-automatic telephone systems and other telecommunication systems, in which power-driven switches are used for the establishment of con nections or for other signalling purposes, and more particularly to improved methods for controlling the positioning of these switches accurately in predetermined stopping positions, resulting in a quick and reliable operation.
  • the principal object of the invention is to provide a double test circuit arrangement for controlling the operation of selector switches of a telecommunication system in which when the stopping operation has once been initiated it will continue for a predetermined time, sufilcient to permit the centering of the wipers of the switch even though they have overshot the desired stopping position, thus permitting the attainment of higher speed and more accurate operation than with apparatus heretofore used.
  • Another object of the invention is to provide an arrangement which permits a bank construction of a selector switch having terminals with which contact is made during a relatively small part only of the total time of the step.
  • the first method is that used with the well known rotary selectors, of which the stopping is based on the time required to perform certain electro-mechanical operations (e. g. operation of test relay, release of loop control relay, release of clutch magnet).
  • a general object against this arrangement is that it has been found impossible to use the test brush for other functions after testing, because its closure is not guaranteed after the finder has been stopped.
  • Such cases of late stopping may occur when a selector meets an outlet which becomes free at a moment the brushes have already partially completed their travel over its terminals, so that the test relay does not start to operate right from the moment the test brush meets the test terminal but some milliseconds later,
  • a second improvement in the operation which may be obtained by the arrangement according to the invention is that when the test circuit controlling the hunting of selectors or line finders contains a cold cathode tube, mechanical centering may be used to advantage in order to obtain a higher speed of hunting than is possible otherwise.
  • a third advantage that may be gained from the arrangement according to the invention is that it permits a bank construction in which the terminals close during a relativel small part of the total time of a step.
  • power-driven switches are used with mechanical centering, preferably by retractile spring action of the movable parts in the stopping positions, in combination with a test arrangement which, upon having been caused to function as a result of the switch arriving in a position in which it should be made to stop, is rendered henceforth inert to the electrical condition prevailing on the test conductor, until after a lapse of time sufficient to cause the switch to be stopped in a centered position, upon which a second test is made to ascertain that stopping has happened in a correct position.
  • one of the elements which constitute the test arrangement is a gas filled tube, which ionizes when the electrical condition on the test conductor indicates that the switch has arrived in a position in which it should stop, and which, from the moment it has ionized, is unafiected by the electrical condition on the test conductor, and thereby causes the continuation of all functions required to stop the switch, also if this should have moved momentarily or definitely beyond the position in which it should stop and thereby caused a transitory opening of the test circuit or the connection of a test potential which may be present in the next stopping position of the switch.
  • the hunting speed of a switch may be increased to the value whereby the time required for stopping exceeds the time during which contact is established with the test contact of the position tested.
  • the hunting speed of a switch of the type which is mechanically centered by the action of a retractile spring in a direction opposite to the direction of hunting is to be determined so that the minimum time required for restraining the switch from further forward motion will, when calculated from the time contact is established with the test contact of a position, bring the switch in the minimum forward position required to permit the mechanical centering device to retract the movable parts to the correct stopping position, whereas the maximum time required to restrain the switch from moving forward will, when calculated from the time referred to, bring the switch in the position before the next centering position, thereby permitting the movable parts to be retracted to the position in which test potential was encountered.
  • the invention makes use of switches of any suitable design permitting mechanical centering of the moving parts in the stopping positions, but preferably of the kind as described in Dutch Patent No. 61,716 of September 15, 1948, to Martinus den I-Iertog, and Belgian Patent No. 464,219 of April 1946, to Martinus den Hertog,
  • the test arrangement used for controlling the hunting of the switch may be of the kind as described in U. S. application Serial No. 765,022, filed July 31, 1947, by L. Cabes, and U. S. application Serial No. 726,359, filed February 4, 1947, by Martinus den Hertog, or may be of the kind as described in U. S. Patent No. 2,424,585 issued to S. Simon et al. or U. S. application Serial No. 765,021, filed July 31, 1947, by L. Cabes, or U. S. Patent application No. 485,327, filed May 6, 1943, by Henry F. Herbig. Any other suitable arrangement may be used which will be inert to the electrical condition prevailing on the test conductor immediately after it has functioned.
  • Figs. 1a and 1b placed side by side in the order mentioned, represent circuit details of a selector switch and of a register circuit controlling the setting thereof.
  • Fig. 2 is a diagram showing relations between hunting speed and stopping time.
  • Fig. 3 represents an alternative testing arrangement in accordance with the invention.
  • One of the purposes of the invention is to eliminate the possibility of incorrect stopping of a switch due to so called late testing, occurring when a selector meets an outlet which becomes free at a moment the brushes have already partially completed their travel over its terminals.
  • the drawing Fig. 1 shows at its left-hand side a part of a register circuit controlling a number of consecutive stages of selectors of which three have been shown, viz.; a 1st group selector, a 2nd group selector and another selector connected in the arc of the 2nd group selector.
  • the 1st group selector has not been shown completely, but is shown only in order to indicate how connections are extended via this selector from the register to the 2nd group selector of which the operation will be described.
  • the selector circuit connected in the bank of the 2nd group selector has also been indicated partially only.
  • the register employs a method of controlling the setting of the selectors known from U. S. application Serial No. 473,278, filed January 22, 1943, by Jakob Kruithof et al., which is based on the comparison of sources of electric current used to characterise different groups of outlets in the selector arc.
  • the particular method, by means of which this comparison takes place, has been disclosed in U. S. application Serial No. 765,021, filed July 31, 1947, by L. Cables, and comprises the two transformers PTI and PT2,
  • the selectors shown are supposed to be of the type disclosed in Dutch Patent No. 61,716 of September 15, 1948.
  • a register and a 1st group selector are seized in the usual manner whereupon a 2nd group selector is seized by the 1st group selector.
  • Fig. l of the drawings shows the necessary portions of these parts after the seizure of the 2nd group selector.
  • the 2nd group selector is now set by the register.
  • the digit controlling the settin will have been stored on a number of storin relays Ql-Ifl, not shown on the drawing but indicated in the upper left corner of Fig. 1, and these will connect via their contacts a source of reference current to the primary winding of transformer PT1 via a 200 w. resistance.
  • this current will cause the ionisation of the cold cathode tube SVl which will supply a rectified AC-component to the system of condensers and resistances connected to its anode, so that these condensers will be charged to a potential sufficiently high to hold the cold cathode tube 8V2, to the control electrode of which they are also connected, in a deionised condition.
  • Hpr connects ground from break contact of relay Wpr and via break contacts of For and Gsr, the 0 brush of the 1st group selector and via a break contact of relay Br and a make contact of relay Ar at the 2nd group selector, to the power magnet P of this selector.
  • relay Ar in the 2nd group selector was already operated in advance at the moment the 2nd group selector was seized by the 1st group selector by ground supplied to it via the a brush of the 1st group selector and through the retardation coil FS at the register in an obvious circuit.
  • the 2nd group selector now rotates until its e brush meets the test terminal of an outlet to which a source of signalling current is connected of which the electrical r characteristics are related in a predetermined manner to those of the source of reference current which is connected at the register to transformer P'Ii, thereby indicating that this outlet is one of the wanted group.
  • the signalling current will be connected via brush 6 of the 2nd group selector, brush b of the 1st group selector, through the primary winding of transformer PT2 and next via brush a of the 1st group selector to a ground supplied at the 2nd group from a make contact of the power magnet P, and a, make contact of relay Ar.
  • the cold cathode tube SV1 extinguishes in the well known manner, so that the set of condensers connected to its anode will discharge and thereby cause the tube SV2 to ionise and relay Wpr to operate. This opens the circuit for the power magnet P of the 2nd group selector.
  • the power magnet P of the 2nd group selector will be de-energised after a certain lapse of time from the moment the test brush e enters into contact with the test terminal of the wanted outlet. This time comprises the de-ionisation time of tube SVl, the discharging time of the con-' densers connected to its anode to a value sufficient to provoke the ionisation of SV2, the ionisation time of SVz, the operating time of the anode relay Wpr, the releasing time of the power magnet P of the 2nd group selector and the time to brake the movable parts of the selector so that they come to a standstill.
  • Line II in this diagram indicates diagrammatically the relation between the time of closure and opening of two successive selector contacts, the line ab or ab' indicates thereby the time during which each contact is closed, whereas the interval ba or ba" indicates the opening in between each two successive contacts.
  • the points 0 and c on the line a-b or a'b indicates the centering position in which the brushes should be made to stop ultimately when the selector seizes the corresponding outlet.
  • the line I in the diagram indicates the corresponding condition of the toothed selector which is provided on the selector frame and over which a pawl is moving durin the rotation of the selector, which pawl is mounted rotatably on the rotor of the selector.
  • the minimum operating time a should be so determined that it always exceeds the time ac because if this requirement would not be met, the selector would not be arrested on the terminal on which it had tested, but would slip back to the preceding terminal.
  • test lead was either opened (e. g. for the time 17-9) or it might have again become closed on the next terminal for the time a.-h.
  • opening nor the connection of another test potential which may be present on the test terminal of the next outlet may aliect however, the functioning of the circuit as described before, because even if by said opening or by the reconnection of another test potential, the tube SV1 should ionise again, it will be unable to extinguish the tube SVz, because this, once ionised, will maintain its ionisation independent of the condition on its control electrode. Therefore, the anode relay Wpr will, in any case, remain operated and cause the continuation of all operations required to stop and center the selector in the correct position.
  • the register circuit now proceeds to make two consecutive tests on the outlet tested, in order to make sure that the selector has stopped on a right outlet.
  • the first test is a test for the presence of battery potential in the outlet, which serves at the same time to take care of possible cases of simultaneous seizure (double test)
  • the second test is a repetition of the test for the presence oi the characteristic signalling potential on the test lead of the outlet, in order to make sure that the outlet is one of the wanted group and that the selector has not stopped accidentally on an outlet of a diiierent group. It will be evident that these tests may commence only after the brushes of the selector have been positioned in the correct centering position.
  • This relay provides sunicient time for the stopping and centering of the selector to be completed. It operates from the make contacts of Wm via break contacts of Gsr and Tar, and when energised, closes a circuit for the operation of the double test relay Dir via brush d of the let group selector and make contact of relay fir brush 0! at the 2nd group selector to test potential found in the outlet tested, via a break contact of relay A1" of that outlet and 24920. If this test is successful, Dtr operates and closes a circuit through the winding of Dpr 311:- its own low resistance winding in parallel rendering the tested outlet busy for other calls.
  • Dpr operates also and prepares a circuit for the operation of C-sr which will be complete when both Hpr and Wm have released. This is caused by relay For which opens the circuit of Hp," and this in turn releases Wpr and extinguishes the valve SVz.
  • Wpr operates again preventing thereby the selector from moving from this outlet because it will open the circuit for the power magnet of the brush carriage at its break contact before this power magnet can energlse and further W 221' will energise relay Okr, which switches the register to a different condiwith its operating circuit, thereby tion in which it will control the next selection and which will also cause the operation of Br of the 2nd group selector in series with AT by openthe ground via the a brush of the 1st group selector. This brings the 2nd group selector in the through-switched condition.
  • a second purpose of the invention is to provide an improved arrangement by which higher hunting speeds of the switches may be obtained than by other known arrangements.
  • the cold cathode tube is caused to fire in a very short space of time (approximately 1 millisecond) after the test brush has entered into contact with a terminal on which the wanted test potential is present, and will not extinguish, even when this test circuit is interrupted immediately thereafter.
  • the firing of the tube causes the stopping of the switch by the consecutive operation of the anode relay and the release of the clutch magnet.
  • the speed of hunting may be chosen to be considerably higher, as the only requirement is that the switch is stopped before it reaches the centering position of the next terminal. In this case it will be reset to the centering position of the terminal On which the tube fired.
  • the brush may temporarily have passed this terminal, or even come into contact with the next terminal.
  • the test circuit is momentarily opened by the brush leaving the terminal, or that the test brush connects momentarily a different potential which may be present on the next terminal, is of no importance, since the cold cathode tube, once fired, cannot be affected any more by any subsequent condition on the test wire and causes the continuation of the further operations required to stop the switch.
  • the sectest to be made on the outlet tested should be made after an interval suificient to permit the mechanical centering device to complete its action to restore the brush carriage to the centering position. As this restoration happens very rapidly, the interval provided by the operating time of an ordinary relay is sufficient for this purpose.
  • next terminal belongs to the same group as the terminal on which the selector tested ini tially, and is free, it will be engaged by the register in the normal way, because the register will proceed with the DC-test and the second AC-test in the manner as described before, and both these testswill be successful. If, however, the next terminal is either busy or belongs to a difierent group of outlets, the register will cause the selector to resume its hunting action. In this case, therefore, the fact of late testing does not cause any trouble, but will simply slightly delay the seizure of a free outlet.
  • the manner in which the register causes the selector to resume hunting is as follows:
  • relay Dtr will fail to energise because it does not find free test potential in the outlet on which the selector stopped. In consequence thereof, a circuit will be closed for the operation of relay Dmr via break contacts of Dtr and Em and the make contact of P01. Dmr opens the circuit from the d brush of the 1st group selector to the double test relay Dtr and instead connects an arrangement suit able for controlling the hunting of the selector and which in this particular case is a static switch Sw such as described in U. S. application Serial No. 765,022, filed July 31, 1947, by L. Cabes.
  • Relay Fir represented on the drawing is the anode relay of the cold cathode tube of the static switch.
  • Dmr connects ground, under the control of a break contact of Ftr, to the 0 brush of the 1st group selector and thereby operates the power magnet P of the 2nd group selector which, therefore, resumes hunting until it meets a free outlet in which battery potential is present on the c2 terminal.
  • the static switch functions, causing Ftr to operate and the power magnet to de-energise.
  • Fir on its make contact and via a make contact of Dmr operates Ter with a delay suificient to ensure that he switch has stopped in its centered position.
  • Gsr by operating, locks itself via a make of Gsr and causes the de-energisation of Hpr. Further Ter opens the circuit for Dior and Dtr which release and in turn cause the release of Gsr. Gsr causes the de-energisation of Ter, which is the last relay energised and which re-closes the circuit for Iipr, so that the operation may now recommence from the beginning.
  • the switch can in no way be forced to engage a wrong or busy outlet, on which it is forced to stop as a result of late testing.
  • the third purpose of the invention is to provide an improved arrangement which permits a bank construction in which the terminals close during a relatively small part of the total time of a step only.
  • the brush carriage comes to rest in the same position on each set of terminals always, and thereby the possibility is provided to reduce the length of the closure to the amount needed to cover only the possible variations of the alignment of brushes and terminals.
  • test circuit contains a gas-filled tube, which is cap-able of firing and then is bound to bring the switch to a stand still, if the test potential is encountered for the short space of time of approximately 1 millisecond only.
  • the facility provided according to the invention to reduce the length of closure of the arc terminals opens up the possibility of employing designs of arc terminals and contacting member hitherto impossible or impracticable.
  • the arc when using a roller type or contact, the arc may be so shaped that the roller passes over isolated metal pieces or dummy terminals located in between each two adjacent arc terminals, so as to avoid the possibility of the roller establishing a momentary short-circuit between these are terminals, or other similar design may be employed resulting in the same effect.
  • FIG. 3 of the drawings shows an alternative the test arrangement. This may be used to advantage in cases where the test arrangement is not provided in a circuit provided in common for a number of switches, but where it has to be provided with every switch individually.
  • Fig. 3 The operation according to Fig. 3 is as follows: The drawing represents one of a number of switches of which the arc contacts are multipled, and of this switch four brushes 0., b, c and d and the power magnet P are shown. It is assumed that upon the arrival of a call one or more switches will hunt for a test terminal (1, to which a free test potential is connected by the closure of a contact S1 and further, that simultaneously the circuit for one or more of the power magnets is closed via an individual contact S2 provided per switch on the starting relay. In such a case,
  • the power magnet P will operat to ground at a break contact T1 of the test relay Tr and cause the brushes to sweep over the arc terminals until the circuit for the test relay is closed at the moinent the test brush encounters free potential.
  • Relay Tr then operates via its 300 ohms winding and at its breakcontact opens the circuit for power magnet P.
  • quick relay which may operate in say 1 millisecond, and then closes a locking circuit via its 60 ohms winding to battery via the winding of Hr and a 400 ohms resistance in parallel.
  • Relay Tr once operated, will therefore hold independent of its operating circuit, so that the test brush, prior to the moment the brushes are brought in a centered position, may open momentarily or even contact with the next test contact in the are for a short instant, without thereby affecting the concondition of relay Tr.
  • relay Hr After a short time, suflicient to complete the centering action of the switch, relay Hr operates.
  • the contacts 01" this relay are so disposed that make contact H1 closes before the break contact of change over H5 opens.
  • ground will be closed through the 7 ohms winding of Tr, in parallel with the 309 ohms winding, before the 60 ohms winding is short circuited at make contact of H5.
  • the relay Tr is an extremely upon which Hr operates, which renders the looking winding of Tr inactive, and causes this to check a second time for the existence of free potential. If this should be absent, for example because of late testing, which caused the switch when running at high speed to overshoot to the next terminal, relay Tr and consequently Hr release again and thereby restore the circuit to the hunting condition. The same happens when in case of double test, one finder succeeds in busying the test terminal before another, as then the relay Hr oi the last mentioned finder, by operating, will also cause the associated test relay to de-energise.
  • contacts H2, H3 and H4 may become momentarily closed, but as both relays Tr and Er will release extremely fast, this time is insignificant, and the closure of these contacts has no further consequences.
  • a selector switch with a plurality of terminals arranged in sets, each set including a test terminal, a plurality of wipers movably mounted and arranged for respective engagement of the terminals of a set, and driving means ⁇ or said wipers for causing successive engagement of said sets of terminals
  • the combination of means for applying a predetermined electrical condition to the test terminal of a set of terminals on which it is desired to stop said wipers means controlled by the initiation of a call for energizing said driving means, for de-energiz-ing said driving means, and means connected to the wiper which engages said test terminals and which is responsive to said predetermined electrical condition for initiating the operation of said de-energizing means
  • said initiating means including means for continuing the operation of said deenergizing means, once it is initiated, for a predetermined time regardless of other electrical- .conditions which may be applied to said initiating means during said time.
  • the means for continuing the operation of the deenergizing means comprises a gas-filled tube and means for ionizing said tube when the predetermined electrical condition appears on the test terminal, said tube being of the type which, from the moment it is ionized is inactive to the electrical conditions on the test terminal and thereby permits continuation of all functions required to stop and center the switch.
  • the responsive means comprises two relays having contacts operated thereby, a circuit connected to a contact of the first of said relays for causing the responsive means to de-energize the driving means when said first relay operates, said first relay having a winding connected to the wiper engaging the test terminals, whereby the first relay energizes when the wiper arrives at a terminal on which said predetermined electrical condition is present, said first relay having a holding circuit closed through one of its own windings and a back contact of said second relay and also including the operating circuit for said second relay, said second relay having a predetermined operating time delay, so that it oper-- ates after a time delay sufiicient for the switch to complete a centering action, the operation of that at the lowest speed of hunting, the minimum time required for restraining the switch from further forward motion upon testing will, when calculated from the moment contact is established with the test terminal of a set of terminals, bring the switch beyond the centering position by at least the minimum distance required to
  • the combination as claimed in claim- 1 further comprising means responsive to a difierent electrical condition, means operated by said de-energizing means for connecting said last-mentioned responsive means to another one of said wipers a predetermined time after said de-energizing means operates, means controlled by the operation of said last-mentioned responsive means for sensitizing said first-mentioned responsive means for a second operation, and means controlled by the second operation of said first-mensaid second relay acting to disable the holding winding of the first relay and thereby causing said first relay to check by means of said windin connected to said test terminal for the presence of said predetermined electrical condition on said test terminal, whereby, depending on the presence or absence of this condition after the centering has taken place, the first and second relays are caused either to hold or to release consecutively.
  • the combination as claimed in claim 1, in which the hunting speed of the switch in a direction opposite to the direction of hunting is adjusted so tioned responsive means in response to said predetermined electrical condition on said test terminal for completing connections to said wipers.

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  • Computer Networks & Wireless Communication (AREA)
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US11403A 1947-01-07 1948-02-27 Telecommunication system Expired - Lifetime US2557638A (en)

Applications Claiming Priority (1)

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NL2557638X 1947-01-07

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US2557638A true US2557638A (en) 1951-06-19

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US (1) US2557638A (fr)
BE (1) BE478817A (fr)
CH (1) CH269664A (fr)
FR (1) FR970842A (fr)
NL (1) NL69440C (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0004786A2 (fr) * 1978-04-10 1979-10-17 Joel Brian Kay Crayons et leurs capuchons

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1592323A (en) * 1921-10-19 1926-07-13 Paul Kolisch Electromechanical device and telephone system
US1799485A (en) * 1928-12-10 1931-04-07 Reserve Holding Co Telephone system
US2068726A (en) * 1937-01-26 Telephone system
US2419540A (en) * 1943-08-28 1947-04-29 Int Standard Electric Corp Telecommunication switching system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2068726A (en) * 1937-01-26 Telephone system
US1592323A (en) * 1921-10-19 1926-07-13 Paul Kolisch Electromechanical device and telephone system
US1799485A (en) * 1928-12-10 1931-04-07 Reserve Holding Co Telephone system
US2419540A (en) * 1943-08-28 1947-04-29 Int Standard Electric Corp Telecommunication switching system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0004786A2 (fr) * 1978-04-10 1979-10-17 Joel Brian Kay Crayons et leurs capuchons
EP0004786A3 (fr) * 1978-04-10 1979-10-31 Joel Brian Kay Crayons et leurs capuchons
US4269523A (en) * 1978-04-10 1981-05-26 Kay Joel Brian Pencils and pencil caps

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FR970842A (fr) 1951-01-09
CH269664A (de) 1950-07-15
BE478817A (fr)
NL69440C (fr)

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