US3025017A - Device for a winding mechanism for record tapes - Google Patents

Device for a winding mechanism for record tapes Download PDF

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Publication number
US3025017A
US3025017A US5876A US587660A US3025017A US 3025017 A US3025017 A US 3025017A US 5876 A US5876 A US 5876A US 587660 A US587660 A US 587660A US 3025017 A US3025017 A US 3025017A
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US
United States
Prior art keywords
tape
forming device
loop forming
coil
piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US5876A
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English (en)
Inventor
Wahlstrom Sven Erik
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atvidabergs Industrier AB
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Atvidabergs Industrier AB
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Publication date
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Publication of US3025017A publication Critical patent/US3025017A/en
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
    • G11B15/56—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function the record carrier having reserve loop, e.g. to minimise inertia during acceleration measuring or control in connection therewith
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
    • G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
    • G11B15/43—Control or regulation of mechanical tension of record carrier, e.g. tape tension

Definitions

  • This invention relates to a device for a winding mechanism for record tapes comprising a loop forming device for the formation of loops in the tape to take up tensions caused by the acceleration of the tape, and a movable means adapted, via a resilient intermediate member to pull the loop forming device into a position for forming at least one loop in the tape, said resilient intermediate member being dimensioned in such a manner that the loop forming device is returned to its home position as the tension in the tape increases.
  • Such an acceleration is required for example for recording or sensing purposes in connection with the socalled start-stop method according to which the tape is moved stepwise, or in cases when the tape feeding is commenced by one tape drive means and continued by another drive means.
  • the device according to the invention which is substantially characterized in that the loop forming device is connected with a preferably adjustable, one-way acting damping device which becomes operative first after said movable means has been moved to the position where iti s pulling the loop forming device into its loop forming position and which is active only during the return motion of the loop forming device as the loops are straightened out.
  • the tape length required for the formation of the loops is preferably as great as or greater than the tape length wound oif or on during a complete acceleration process covering the period from the standstill of the coil to its full velocity so that during the acceleration process the tension of the tape will be the smallest possible.
  • FIG. 1 is a side view of a storage device showing the loop forming device and a damping device, the latter being of the pneumatic type.
  • FIG. 2 shows the loop forming device and the clamping device in a position occupied by said devices during a later phase of the operation, and illustrates (in schematic manner and on a reduced scale) further details of the storage device.
  • FIG. 3 is a side view corresponding to FIG. 2 showing the loop forming device and the damping device in winding position of the coil.
  • FIG. 4 is a longitudinal section of the damping device on an enlarged scale.
  • FIG. 1 shows a coil 1 from which a record tape 2 i is unwound.
  • the unwinding operation is eiiected partially by a weight 3 fastened to the end of the coil and under the influence of gravity mov ing downwards in a track 4, and partially by an electrornotor (not shown) coupled to the shaft 5 of the coil 1.
  • the loop forming device designated in its entirety by 7 is provided on the side of said track 4 very close to the upper end of the track and is located right in front of the damping device designated in its entirety by 8, provided on the opposite side of the track 4.
  • the clamping device ti appears more clearly in FIG. 4.
  • a magnetic head 9 is provided (shown schematically in H63.
  • a capstan 11 and in cooperation therewith a pressure roller 12 is arranged below the magnetic head 9 and the tape supporting member 10 on opposite sides of the track 4 in such a manner that by action of a solenoid 14 (shown schematically) the pressure roller 12 can be advanced to press the tape 2 against the continuously rotating capstan 11 so that the tape is unwound at a high velocity past the magnetic head 9.
  • a fork 15 with two prongs is provided below the rollers 11 and 12 to embrace the opposite edges of the tape and in active posiion to engage with recesses 16 in the one wall of the track 4 thereby preventing the weight 3 from being pulled upwards past the fork 15 when, in connection with the change of the drive means from the motor (not shown) to the tape drive means 11-12 for unwinding the tape, the loop forming device 7 is turned from the position according to FIG. 1 into the position according to FIG. 2. At the bottom of the FIGS.
  • a light source 17 and a photo-cell 1% located on opposite sides of the track 4 and forming together an optical indicator by means of which the aforementioned change of the tape drive means is initiated when "the path of the light beams from the light source 17 to the photo-cell 18 is interrupted by the weight 3.
  • the loop forming device 7 comprises a crank having two slightly curved legs 20, 21 which at their ends are provided with rotatable tape rollers 22 and 23 respectively.
  • the loop forming device and an arm 25 rigidly connected therewith are fastened on a pivot axis 24.
  • the loop forming device in its entirety is located on the side of the track 4.
  • the legs 20, 21 with their rollers 22, 2.3 can be pivoted into the spaces between three tape guiding members having the form of rollers 27, 28, 29 which are arranged on the side of the track 4 opposite to the side on which the pivot axis 24 of the loop forming device 7 is located, so that two loops are formed in the tape when the loop forming device is pivoted from the position according to FIG. 1 into the position according to FIG. 2.
  • the arm 25 carries a pivotal piston rod 30 to which is secured a piston 31 movable in a cylinder 32 having one substantially open and one substantially closed end, both the piston 31 and the cylinder 32 constituting a part of the damping device 7 which is more clearly illustrated in FIG. 4.
  • the piston 31 is a thin disc cut from a sphere having its edges curved in such a manner, that in all directions their radius of curvature (that is the radius of the sphere from which the disc is cut out) is like the radius of the cylinder 32, causing the piston 31 to abut tightly to the cylinder wall even if owing to the pivotal motion of the loop forming device 7 the piston rod 30 forms an angle with the cylinder axis.
  • a plurality of perforations 33 disposed in the piston 31 are covered by a diaphragm 34, for example of plastic, attached to the piston 31 on the side facing the open end of the cylinder 32.
  • Said perforations 33 and said diaphragm 34 form a check valve designed to seal when the piston 31 moves to the left in FIG. 4 and to open when the piston moves to the right.
  • the substantially closed end 36 of the cylinder 32 is provided with an adjustable throttle valve 37 to control the velocity of the air flowing into the cylinder portion located between the piston 31 and said end 36.
  • the substantially closed end 36 is further provided with an air outlet channel 38 which cooperates with a movable sealing plug 39 (FIGS.
  • a preferably resilient stop member 48 which is fastened to the flat iron 47 and the angle bar 41 serves in cooperation with the journal 45 as a stopper to limit the counterclockwise pivotal motion of the loop forming device 7.
  • the journal 45 abuts against said stopper 48 as shown in FIG. 3.
  • the sealing plug 39 is moved to the opening of the air outlet channel 38 and the loop forming device 7 is pivoted by means of the resilient connection 4741-42--43--45- 7 from the position according to FIG. 1 into the position according to FIG. 2, the piston rod 31 ⁇ and the piston 31 at the same time being moved to the right, all this occurring immediately after the engagement of the fork 15 with the recesses 16 and after the tape supporting member 10 has moved the tape 2 towards the magnetic head 9.
  • the weight 3 When during the first phase of the unwinding operation which is effected by the weight 3 and by the motor coupled to the shaft 5 of the coil 1, the weight 3 interrupts the light beams from the light source 17, the motor is stopped and the control carriage is moved to its right end position.
  • the fork 15 is caused to engage with the recesses 16 in order to prevent the loop forming device 7 during its immediately subsequent clockwise pivotal motion around the pivot axis 24 lifting the weight 3, and the tape supporting member 10 is moved towards the magnetic head 9.
  • the second phase of the unwinding operation is commenced by energizing the solenoid 14 causing the pressure roller 12 to press the tape 2 against the capstan 11 by which from that moment the unwinding operation is taken over.
  • the primary object of the loop forming device 7 in this connection is to decrease the tension caused in the tape 2 during the subsequent acceleration process. Said object is attained in that the loop forming device, owing to the tension of the tape, is turned in a counterclockwise direction from the position according to FIG. 2 into the position shown in FIG. 3. During this pivotal motion, the piston rod 30 and the piston 31 are moved to the left by arm 25 until this motion is braked by the outside air pressure against the left side of the piston 31.
  • the loops are more or less shortened without causing the coil 1 to accelerate considerably, the velocity of the loop forming device 7 and of the piston 31 and the resistance of the clamping device decreasing according to the acceleration of the coil.
  • the full length of the tape portion taken up by the loop forming device it is necessary to use, during the acceleration process, the full length of the tape portion taken up by the loop forming device. This means that the loops must have a total length which is at least as long as the tape portion advanced during the acceleration process, covering the period from the tape in standstill position to full velocity of the coil 1.
  • the circumferential velocity of the capstan 11 is, in the embodiment described, 5 meters per second which is substantially more than the maximum velocity of the 4 tape during the phase of the unwinding operation described above. Therefore the coil 1, which is substantially standing still at the moment when the pressure roller 12 is beginning to force the tape 2 towards the capstan 11, is given a kinetic energy corresponding to the tape velocity 5 meters per second, that is of the magnitude one kilogram-centimeter, without exceeding the allowable maximum tension in the tape, in this case 0.3 kilogram.
  • This is realized by means of the loop forming device 7 which in the embodiment shown forms two loops, i.e. four parts in the tape 2 causing the tension of the tape to be reduced substantially to one quarter compared with a straight tape.
  • the loop forming device must take up a tape length of about 3-4 centimeters to be able to supply said kinetic energy at a tension of 0.3 kilogram, but owing to other circumstances explained below the loop forming device is designed to take up a total tape length of about 10 centimeters.
  • the loop forming device described has many advantages when the analyzing and recording operations are carried out according to the so-called start-stop method comprising the steps of seeking out successively addresses on the tape which are located at an increasing distance from the tape end fastened to the coil, in order to commence the sensing or recording operation in these addresses, the tape being stopped after each sensing or recording operation and thereafter started again, for instance after that the partial information received is processed.
  • start-stop method comprising the steps of seeking out successively addresses on the tape which are located at an increasing distance from the tape end fastened to the coil, in order to commence the sensing or recording operation in these addresses, the tape being stopped after each sensing or recording operation and thereafter started again, for instance after that the partial information received is processed.
  • the loop forming device 7 draws the tape portion which is located below the loop forming device upwards past the magnetic head 9, the pivotal motion of the loop forming device being accelerated by means of the check valve 33-34 which opens as the piston moves to the right. Owing to the inertia of the drive mechanism 1112 and to the necessary braking time of the coil 1, there will be a certain retardation or stopping distance of the tape (measured from the magnetic head 9 downwards) from the instant when the stop impulse was given to the instant when the tape velocity directly in front of the magnetic head 9 is zero.
  • the solenoid 14 is supplied with current causing the pressure roller 12 to be advanced to press the tape against the capstan 11 whereafter the tape is accelerated, while at the same time the loops formed by the loop forming device 7 are straightened out until the state shown in FIG. 3 is restored.
  • the loops formed by the loop forming device 7 must have a total length which is at least equal to the sum of the maximum tape length which during a complete retardation process covering the period from normal tape velocity to its stop is fed past the magnetic head 9, and of the maximum tape length which during a complete acceleration process consecutive to the retardation process and covering the period from the stop of the tape to its normal velocity is fed past the magnetic head 9 (the tape velocity being measured in a point right in front of the magnetic head).
  • the substantially pneumatic clamping device can be replaced by a spring system or by another similar device.
  • resilient damping means are less suitable than substantially inelastic damping means, because the acceleration occurs more uniformly with the latter type of damping means and the tape is sensed more smoothly, while with resilient damping means each return motion of the loop form-ing device 7 to the position according to FIG. 1 occurs with a jerk.
  • a loop forming device is actuated by an elastic clamping device, there will be the risk that said loop forming device when it is moved from its position according to FIG. 2 into the position according to FIG. 3 will be swung back into the direction of its starting position, whereby the coil 1 receives an additional rotary impulse or after-touch causing the tape 2 to become disordered on the coil.
  • a take up device for a winding mechanism for recording tapes on a recording machine provided with a tape supply coil and a recording head, said device comprising a loop forming device for the formation of loops in the tape to take up tensions caused by the acceleration of the tape, a movable means adapted to pull the loop forming device into a position for forming at least one loop in the tape, a resilient member between said loop forming device and said movable means, said resilient member being so dimensioned that the loop forming device may return to its home position as the tension of the tape increases, an adjustable, one-way acting pneumatic damping device comprising a fixed cylinder with one substantially open and one substantially closed end and a movable piston connected to said loop forming device adapted to move towards the open end of the cylinder as the loops are straightened, said damping device being provided with a check valve closing as the piston moves in said direction but opening as the piston moves in the opposite direction, an adjustable throttle valve, a sealable air outlet channel in said substantially closed end, and
  • said loop forming device carries said tape between said tape supply coil and said recording head and in which, upon stopping of movement of the tape through the recording machine, the loop forming device pulls tape back that has progressed past said loop forming device to form part of said loop whereby upon starting said tape again, said tape again passes said recording head.

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  • Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)
  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
US5876A 1959-02-13 1960-02-01 Device for a winding mechanism for record tapes Expired - Lifetime US3025017A (en)

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SE143259 1959-02-13

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DE (1) DE1248724B (de)
GB (1) GB906351A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3125309A (en) * 1964-03-17 moyano
US3217996A (en) * 1962-04-02 1965-11-16 Sanders Associates Inc Tape transport mechanism
US3299787A (en) * 1962-11-27 1967-01-24 Harris Intertype Corp Electrophotographic micro-copy printer
US3761038A (en) * 1971-03-30 1973-09-25 Garlock Inc Tape-wrapping method and apparatus
US4798353A (en) * 1987-02-05 1989-01-17 Printpack, Inc. Web slitting system and slack inducing apparatus and method useful therein
US6216934B1 (en) * 1998-09-14 2001-04-17 Timothy J. Searles Festoon protection method and system
US20110062206A1 (en) * 2008-05-20 2011-03-17 Khs Gmbh Roll or buffer storage for a flat web material

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4441664A (en) * 1982-07-26 1984-04-10 Anderson Bros. Mfg. Co. Apparatus for feeding web material from a supply roll
DE3410470A1 (de) * 1984-03-22 1985-10-03 Focke & Co, 2810 Verden Vorrichtung zum transport von verpackungsmaterial-bahnen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1539408A (en) * 1923-12-19 1925-05-26 Anna M Pigeon Yarn-tensioning device
FR722400A (fr) * 1930-09-04 1932-03-16 Brugger & Co Dispositif de réglage du dévidage du fil de bobines fixes
US2006628A (en) * 1933-03-11 1935-07-02 Allan J Cline Web controlling device for printing presses

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1539408A (en) * 1923-12-19 1925-05-26 Anna M Pigeon Yarn-tensioning device
FR722400A (fr) * 1930-09-04 1932-03-16 Brugger & Co Dispositif de réglage du dévidage du fil de bobines fixes
US2006628A (en) * 1933-03-11 1935-07-02 Allan J Cline Web controlling device for printing presses

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3125309A (en) * 1964-03-17 moyano
US3217996A (en) * 1962-04-02 1965-11-16 Sanders Associates Inc Tape transport mechanism
US3299787A (en) * 1962-11-27 1967-01-24 Harris Intertype Corp Electrophotographic micro-copy printer
US3761038A (en) * 1971-03-30 1973-09-25 Garlock Inc Tape-wrapping method and apparatus
US4798353A (en) * 1987-02-05 1989-01-17 Printpack, Inc. Web slitting system and slack inducing apparatus and method useful therein
US6216934B1 (en) * 1998-09-14 2001-04-17 Timothy J. Searles Festoon protection method and system
US20110062206A1 (en) * 2008-05-20 2011-03-17 Khs Gmbh Roll or buffer storage for a flat web material
US8973801B2 (en) * 2008-05-20 2015-03-10 Khs Gmbh Roll or buffer storage for a flat web material

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GB906351A (en) 1962-09-19
DE1248724B (de)

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