US3580526A - Apparatus for storing and winding discontinuously and reversibly moving tape - Google Patents

Apparatus for storing and winding discontinuously and reversibly moving tape Download PDF

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US3580526A
US3580526A US855550A US3580526DA US3580526A US 3580526 A US3580526 A US 3580526A US 855550 A US855550 A US 855550A US 3580526D A US3580526D A US 3580526DA US 3580526 A US3580526 A US 3580526A
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tape
spool
spools
arms
voltage
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US855550A
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Michel Wichoud
Jean Pierre Engel
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/32—Details specially adapted for motion-picture projection
    • G03B21/43—Driving mechanisms

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  • P'atentea may 25, 197i 5 Sheets-Shoot 1 FIG.
  • Such a problem may for instance occur when designing magnetic tape sound reproduction apparatus, motion picture projection or filming apparatus and programme reading apparatus for controlling various machines, or with certain tape readers used in computer peripheral equipment.
  • An object of the present invention is to avoid such a requirement.
  • apparatus for storing and winding discontinuously and reversibly moving tape comprising a pair of holders for supporting a pair of tape spools; a pair of reversible motors for'reversibly driving said holders whereby said spools may be alternately receiving and delivering; tape reading means in the path of said tape between said spools; drive means for driving said tape as it enters and as it issues from the reading means; a tape takeup system in the path of said tape for temporarily modifying the length of first and second portions of said path between said drive means and said spools; first supply means actuated" by said system and adapted to supply, for each of the spools, a first electric index voltage dependent of the length of the corresponding one of said tape path portions; second supply means associated with each of said spool holders and adapted to supply, for each of the spools, a second electric index voltage dependent on the radius of the last turn of tape wound on the corresponding spool; and electronic circuit means having a
  • FIG. 1 is a front elevation of one form of embodiment of the apparatus provided by the invention.
  • FIG. 2 is a side elevation of the apparatus shown in FIG. 1, on a larger scale; 1
  • FIG. 3 is an axial section, along line III-III of FIG. 4 and to a larger scale, of part of the apparatus shown in FIGS. 1 and 2;
  • FIG. 4 is a section taken along line IV-IV of FIG. 3;
  • FIG. 5 is an explanatory graph illustrating the operation of the apparatus shown in FIG. 1 and 2;
  • FIG. 6 is a diagram of an electronic circuit used in the apparatus shown in FIGS. 1 and 2.
  • the apparatus shown in FIG. 1 comprises a baseplate l on the front side of which are mounted two delivery cum receiving spools 2 and 3 carried and driven by rotary supports 21 and 31 and containing a tape 4; a drum 5, having a rotary shaft 51, for driving the tape intermediate the two spools; two sets 6 and 7 of pulley arrangements lying in the path of the tape, each between one of the spools 2 and 3 and the driving drum 5; two feelers 8 and 9 pivotally mounted on pins 81 and 91 and carrying at their free ends follower rollers which come to bear under the action of springs 10 and 11 against the outermost turn of tape that is wound on the associated spools.
  • the two sets of pulley arrangements are made up of four rollers 61, 62, 63 and 64, and of four rollers 71, 72, 73 and 74, respectively, that are mounted for free pivotal movement on the baseplate and of three rollers 65, 66 and 67, and of three rollers 75,76 and 77, respectively, that are mounted for free pivotal movement also on arms 12 and 13. .
  • the tape 4 alternately passes over one of the rollers that are pivotally mounted on the baseplate and over one of the rollers that are pivotally mounted on an arm.
  • Arms 12 and 13 are mounted on pivot pins 121 and 131 and are subjected to the action of tension springs 14 and 15 having one end secured to the arms and having the other end secured to the baseplate 1.
  • the baseplate 1 carries a unit 17 for reading the information recorded on the tape 4.
  • a motor 18 for driving the drum 5 On the reverse side of the-baseplate are mounted, as shown by FIG. 2, a motor 18 for driving the drum 5; potentiometers l9 and 20 having control pins that are common with the pins 81 and 91 of feelers 8 and 9; potentiometers 22 and 23 having control pins that are common with the pins 121 and 131 of arms 12 and 13; motors 24 and 25, each fitted with reduction gearing, for driving spools 2 and 3; and a drive unit 26 for moving the tape through the reading unit 17.
  • the supply terminals of motors 24 and 25, of motor 18, of drive unit 26, and of potentiometers 19, 20, 22 and 23, are connected by leads, not shown, to connectors that are mounted on a bus bar 101 secured to the back of the baseplate 1. Other leads, not shown, connect some of the connectors 100 to the electronic circuit shown in FIG. 6.
  • This electronic circuit which is transistorized, can be mounted on a support that can either be secured to the base plate 1 or be separate therefrom.
  • the tape 4 Upon issuing from one of the spools 2 and 3 (the delivery spool), the tape 4 is fed to the drum 5 via the corresponding set of pulley-arrangements. It then cooperates with the drum a first time and then proceeds along a loop-shaped path towards the reading-unit 17 through which it passes. Upon issuing from this reading unit, the tape proceeds back to the drum along a path that is also loop-shaped. The tape then again cooperates with the drum 5, whereupon it proceeds, via the other set of pulley arrangements, towards the other, receiving, spool on which it is wound.
  • the angular position of the feelers 8 and 9 depends on the amount of tape the spools 2 and 3 carry.
  • the drum 5 is provided with sprocket teeth 51' (FIG. 3) for engagement with perforations formed along the edges of the tape 4 to drive the latter.
  • a rotary member not shown, provided in the reading unit 17 to drive the tape therethrough. The latter is thus driven by both the drum and by this rotary member in the reading unit so .that the mean linear speedsat which the drum and this rotary member are drivenmust be the same.
  • the drum 5 is mechanically connected to the shaft 181 of motor 18 via a rubber coupling element 182 having four limbs 182a, 182b, 1826' and 182d arranged in quadrature formation and giving this element the appearance of a Maltese cross, as can be seen from FIG. 4.
  • the ends of the pair of opposite limbs 182a and 182b are connected to the ends of a diametral element 183, keyed to the motor shaft 181, by connection elements 184.
  • the ends of the pair of opposite limbs 182c and 182d are similarly connected to the rear part of the drum 5 by connection elements 185.
  • the coupling element 182 is so cut out that each of its limbs may, by elastic deformation, move away from its mean position by .-ior 45.
  • One of the extreme positions the limbs 182C and 182d can occupy is shown in dashed lines in FIG. 4.
  • the motor 18 is fitted with an instantaneous blocking device 186 which comprises a rotary metal disc 187 carried by the opposite end of shaft 181 and coaxial therewith and an electromagnet 188 for axially actuating a nonrotary rubberlined disc 189 which, upon the electromagnet ceasing to be energized, is applied by spring means, not shown, against the disc 187 toblock rotation thereof.
  • This blocking device is meant to be actuated only when the apparatus is being stopped and started.
  • the electronic circuit shown in FIG. 6 is provided twice, the first time in association with the group consisting of the motor 24 and the potentiometers 19 and 22, and the second time in association with the group consisting of the motor 25 and the potentiometers 20 and 23, with the portion which is surrounded by a dashed line being common to both of these two circuits, and only one of these circuits will now be described.
  • the energization circuit for the motor 24 or driving spool 2 or 3 is connected to terminals A, and A provided in a diode bridge D, D D D These terminals A, and A are connected one to terminals J, and 1', the other to terminals J and J of a reversing switch J having input terminals J and .I'; which can selectively be connected to the terminals J, and 1'': or J and J', depending on the direction in which the motor is required to rotate.
  • the linear potentiometer 22 or 23 has extreme terminals B, and B, which are connected one to terminals K, and K', the other to terminals K and K of a reversing switch K having input terminals K and K, which can selectively be connected to the terminals K, and K or K and K', depending on the direction in which motor 24 or 25 is required to rotate.
  • the potentiometer also has extreme, equipotential, zones B and 5.
  • potentiometer 22 or 23 is dependent on the angular position a of arm 12 or B of arm 13, that is common with the control pin of the potentiometer, and on the direction of movement of the tape.
  • This direction of movement is determined, under continuousduty operating conditions of the apparatus, by the sign of the angular speed 0) of drum 5, which is arbitrarily chosen to be positive when the drum rotates in the direction of arrow F (FIG. 1).
  • the angles a and B are reckoned to be positive in the direction of arrows F, and F from the leftmost position of arms 12 and 13 in FIG. 1.
  • Voltages v and v respectively vary between 0 and maximum values V and V which are maintained up to angular positions a, and B, of arms 12 and 13 when m 0, or which are reached at angular positions a, and B, of arms 12 and 13 when w 0, and maintained, in this event, up to the maximum angular positions 01 and B, of arms 12 and I3.
  • FIG. 5 shows, in full lines when w O and in dashed lines when w 0, the variation of voltages v and v as functions of a and [3, respectively.
  • Angles a, and [3, determine the position of terminal B, and angles a and B determine that of terminal B on this resistive element.
  • Potentiometer 19 'or 20 is subjected, between its extreme terminals, to a voltage V,,, or V having a variable fraction v, or v which is picked off by the potentiometer slide C and which is applied, via a diode D to the input terminal K;, of the reversing switch K.
  • the position of the slide C, and hence the value of voltage v,,, or v is determined by the angular position of the feeler 8 or 9, which angular position depends on the extent to which spool 2 or 3 is filled, this being characterized by the radius r, or r, of the last turn of tape wound on the corresponding spool.
  • this machine supplies, for instance, through the intermediary of a tachymetric generator not shown, a voltage U which is proportional to its linear speed V,, to which the present apparatus has toadjust its rate of operation.
  • This circuit portion delivers, through the intermediary of an input potentiometer P, voltage V,,, or V these two voltage being identical, so that there is obtained the following relationship:
  • Voltage V or V is applied to a load resistor R
  • the following table shows the values that are given to the A resistor R placed at the output of the slide B of potenvarious resistors in the circuit represented in FIG. 6: tiometer 22 or 23, and a resistor R placed at the output of the slide C of potentiometer 19 or 20, enable the power level to be V l V 1 adapted at point Q and are loaded by a resistor R
  • the voltage 20 .1 55 5% V at point Q is of the form:
  • a servocircuit is provided so as permanently to regulate the energization of motor 24 or 25 in dependence on the value of parameters r and a or r; and B, respectively, i.e. to subject the speed of the motor to these parameters.
  • This servocircuit comprises a comparator cum amplifier CA having a feedback line (resistor R capacitor C by means of which the gain can be increased.
  • Comparator cum amplifier CA has two inputs E and E To the first, E is applied the index voltage V to the second, 5;, is applied a voltage V, from point S and termed measurement voltage, which is proportional to the energizing power of motor 24 or 25 and which is derived from this power, ofi terminal 1, of the reversing switch J, via a resistor R loaded by a resistor R Comparator cum amplifier CA serves to reverse one of its input voltages, V then to add it to the other, V,, and to amplify the quantity V,V, thereby to supply, at its output E an error signal 5 having a sign which is the same as that of V,V,,.
  • resistors R R R R and R are so chosen that under continuous-duty operating conditions of the apparatus, this error signal may be nil or remain less than a threshold value at which the servoaction is triggered off, iLe. that V,, may be substantially equal to V,.
  • This amplifier which comprises resistors R R R R and R transistors T T T and T diodes D and D and a chemical capacitor C, delivers to the terminal J of reversing switch J the energizing power for motor 24 or 25.
  • the circuit includes a portion which consists of diodes D and D transistors T, and T resistors R R R and R and which enables the current discharged by the motor 24 or 25 to be absorbed and to be limited when the latter, upon reversal of its energization by actuation of the reversing switch J, operates, through inertia, as a generator before stopping and reversing its direction of rotation.
  • Current sources P,, P; and P discharge at constant voltages V V and V respectively.
  • the speed of the motor controlling the rotary member that drives the tape in the reading unit 17 and the speed of the motor driving drum 5 are adjusted to the speed of operation, V,,,, of the machine to which the apparatus is fitted.
  • These two motors can, to this end, be driven by impulses emitted by the machine and having a frequency proportional to V
  • the operation of the drum motor remains, however, dependent on that of the motor controlling the rotary member in the reading unit.
  • the mean linear speed of the tape 4 is uniform and is the same over its entire path of travel, i.e. from when it is unwound off the delivery spool (3 if w 0 2ifw 0) until it is rewound on the receiving spool (2 if m 0 3 if w 0).
  • the motion of the tape through the reading unit 17 remains jerky but the mean linear speed of the tape is the same as the even speed over the drum 5.
  • a counting circuit not shown, is provided to trigger off, outside the periods in which the direction of travel of the tape is reversed, one step of the drum motor for every three steps of the reading unit motor, the angular ahTpfiide of the steps of theset wo motors being of course dependent on the diameter of the drum and on the diameter of the tape driving member in the reading unit so that the linear speed of the tape may, on average, be the same over the drum and in the reading unit.
  • the arms 12 and 13 remain in a substantially mean angular shown in full lines in FIGS. 1.
  • the comparator cuni amplifierCA br'fiie electronic circuit that is associated with the potentiometers l9 and 22 and with the motor 24, delivers an error signal e proportional to variation in the speed V,, that characterizes the operating conditions, or the working rate, of the machine with which the present apparatus is associated, or a variation in the angular speed of the spools 2 or 3 in relation to the value this speed has under continuous-duty operating conditions, or else a change in the value or of the sign of to.
  • V,V 0 which, by acting on the base of the transistor T pared to the decreasing voltage V
  • Spool 3 is delivering: r, is decreasing and v is increasing.
  • the comparator cum amplifier CA of the circuit that is associated with the potentiometer 20 and 23 and with the motor 25, delivers an error signal e 0 proportional to V,-V 0 which, by acting on the base of the transistor T causes the current i to decrease and hence brings about an increase of the current i and, via the circuit for amplifying the power for the energization of motor 25, an acceleration of this motor.
  • the voltage V is thus increased and again compared with the decreasing voltage V
  • the circuit which is associated with the potentiometers l9 and 22 and with the motor 24 reacts to this decrease of r, in the same way as the circuit which is associated with the potentiometers 20 and 23 and with the motor 25 when w 0, and so causes the motor 24 to accelerate.
  • Spool 3 is receiving and r, is increasing.
  • the circuit which is associated with the potentiometers 20 and 23 and with the motor 25 reacts to this increase of r: in the same way as the circuit which is associated with the potentiometers l9 and 22 and with the motor 24 when (n O, and so causes the motor 25 to slow down.
  • FIG. 5 shows that this decrease of or causes v,, to increase and hence, all other things being equal, an increase of V, and the appearance of a difference V,V 0 causing the comparator cum amplifier CA to emit an error signal e 0 which causes i to become smaller and hence i, to become larger.
  • This larger i causes the energization of motor 24 to increase thereby accelerating spool 2 and reducing the excess length of tape between the spool and the drum 5, thus causing an increase of a which, progressively and at the same time as the angular speed of this spool, returns to its continuous-duty operating conditions value.
  • the tape 4 is alternately read in one direction of travel and then in the other ((o 0 and m 0).
  • the reversal of this direction of movement is triggered off by the reading of a reversal item of information carried by the'tape and occurs'instantaneously in the reading unit.
  • This reversal causes, through the intermediary of an electromagnet not shown, the reversing switches J and K to change over.
  • the previously mentioned counting circuit triggers off the first reversed step of the drum motor only afterthe reading unit motor has moved, in its new direction of rotation (3n+x) steps, x being the number of steps made by this motor in its previous direction of rotation between the time the last drum motor step was triggered off and the time when the reversal item of information was read.
  • the number I may be equal to 3, 4 or even 5.
  • the changing over of the reversing switch J causes the value of v as a function of a, or of v as a function of B, to pass from one curve of FIG. to the other, whereas the changing over of the reversing switch K reverses the energization ofmotors 24 and 25.
  • This kinematic reversal time may amount to a few tenths of a second in the case of a linear tape travel speed of about 100 cm/sec. it depends, in the case of each spool, on the extent to which it is filled.
  • the tape 4 continues, during this kinematic reversal time, to be wound by spool 2 and to be unwound by spool 3 when it is in fact already being driven in the opposite direction by the drum 5 and in the reading unit 17, :0 having become negative.
  • both motors 24 and 25 Upon being so driven, both motors 24 and 25 operate as generators and the current they supply is looped through earth via the diode bridge (D,, D D D and the transistor T, which becomes unblocked as soon as the value of the voltage at the terminals of resistor R exceeds a threshold value.
  • This current exerts a braking action on the motor which slows down.
  • the voltage at the terminals of resistor R decreases and because this current is now decreasing as a result of the motor slowing down, the transistor T becomes blocked as soon as the voltage at the terminals of resistor R,, has dropped back below said threshold value.
  • the motors 24 and 25 then stop whereupon they reverse their direction of rotation and gather up speed while causing a and B to decrease.
  • Apparatus for storing and winding a discontinuously and reversibly moving tape comprising a pair of holders for supporting a pair of tape spools; a pair of reversible motors for reversibly driving said holders whereby said spools may be alternately receiving and delivering; tape reading means in the path of said tape .between said spools; drive means for driving said'tape as it enters and as it issues from the reading means, a tape takeup system in the path of said tape for temporarily modifying the length of first and second portions of said path between said drive means and said spools; first supply means actuated by saidsystem and adapted to supply, for each of the spools, a first electric index voltage dependent on the length of the corresponding one of said tape path portions; second supply means associated with each of said spool holders and adapted to supply, for each of the spools, a second electric index voltage dependent on the radius of the last turn of tape wound on .the corresponding spool; and electronic circuit.
  • the tape can unwind off thedelivering'spool and can be wound on the receiving spool at a linear speed equal to that at which it is driven by said drive means, with said first index voltage remaining constant and said second reference voltage, which is variable, progressively modifying the angular speed of the spool associated therewith, and such that any modification in the length of the tape along said path portions causes the takeup system to come into operation and a corresponding variation of the first index voltage to occur which triggers off transitional operating conditions tending to restore said tape path portions to their previous length under continuous-duty operating conditions.
  • first and second pivot pins mounted in said f baseplate in the vicinity of said spool holders and which carry at their free ends first and second follower rollers for engagement with the last turn of tape wound on said spools, respectively, when mounted on said holders, first and second spring means cooperating with said first and second feeler arms to urge said follower rollers, during operation, into engagement with the last turn of tape wound on said spools, and first and second linear potentiometers controlled by said first and second pins, the value of said second electric index voltage supplied during operation by said second supply means for each spool being dependent on the angular position of the corresponding one of said feeler arms, said angular position being in turn dependent on the radius of the last turn of tape wound on the corresponding spool.
  • said comparing element for each spool is a comparator cum amplifier having a first input for receiving an index voltage resulting linearly from said first and second electric index voltages, and having a second input for receiving a measurement voltage which is proportional to the power for energizing the corresponding spool-holder driving motor, the difference between the measurement voltage received at said second input and the index voltage received at said first input being amplified by said comparator cum amplifier and giving rise to an error signal, either positive or negative, which reacts on the energization of said corresponding motor and hence on the angular speed of the spool-holder driven by said motor.

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  • General Physics & Mathematics (AREA)
  • Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)
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US855550A 1968-09-06 1969-09-05 Apparatus for storing and winding discontinuously and reversibly moving tape Expired - Lifetime US3580526A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1343268A CH498763A (fr) 1968-09-06 1968-09-06 Dispositif pour le stockage et l'enroulement d'un ruban à avancement discontinu et reversible

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US3580526A true US3580526A (en) 1971-05-25

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US855550A Expired - Lifetime US3580526A (en) 1968-09-06 1969-09-05 Apparatus for storing and winding discontinuously and reversibly moving tape

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US (1) US3580526A (fr)
CH (1) CH498763A (fr)
DE (1) DE1945800A1 (fr)
FR (1) FR2017509A1 (fr)
GB (1) GB1244896A (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3115314A (en) * 1961-02-01 1963-12-24 Litton Systems Inc Tape handling apparatus
US3251048A (en) * 1962-02-28 1966-05-10 Minnesota Mining & Mfg Magnetic tape transport system
US3318546A (en) * 1964-09-28 1967-05-09 Minnesota Mining & Mfg Tape transport system
US3488696A (en) * 1967-05-15 1970-01-06 Potter Instrument Co Inc Proportional reel servo system
US3523655A (en) * 1967-09-15 1970-08-11 Chalco Eng Corp Tape transport apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3115314A (en) * 1961-02-01 1963-12-24 Litton Systems Inc Tape handling apparatus
US3251048A (en) * 1962-02-28 1966-05-10 Minnesota Mining & Mfg Magnetic tape transport system
US3318546A (en) * 1964-09-28 1967-05-09 Minnesota Mining & Mfg Tape transport system
US3488696A (en) * 1967-05-15 1970-01-06 Potter Instrument Co Inc Proportional reel servo system
US3523655A (en) * 1967-09-15 1970-08-11 Chalco Eng Corp Tape transport apparatus

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GB1244896A (en) 1971-09-02
FR2017509A1 (fr) 1970-05-22
CH498763A (fr) 1970-11-15
DE1945800A1 (de) 1970-03-12

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