US3633804A - Tape-detecting device for tape recorders - Google Patents

Tape-detecting device for tape recorders Download PDF

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Publication number
US3633804A
US3633804A US48025A US3633804DA US3633804A US 3633804 A US3633804 A US 3633804A US 48025 A US48025 A US 48025A US 3633804D A US3633804D A US 3633804DA US 3633804 A US3633804 A US 3633804A
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US
United States
Prior art keywords
tape
conductive
conductive member
detecting device
discontinuous
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
US48025A
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English (en)
Inventor
Ryozo Kitazawa
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.)
Nippon Chemical Industrial Co Ltd
Original Assignee
Nippon Chemical Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP44050768A external-priority patent/JPS5122368B1/ja
Priority claimed from JP45000135A external-priority patent/JPS516528B1/ja
Application filed by Nippon Chemical Industrial Co Ltd filed Critical Nippon Chemical Industrial Co Ltd
Application granted granted Critical
Publication of US3633804A publication Critical patent/US3633804A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • G11B15/675—Guiding containers, e.g. loading, ejecting cassettes
    • G11B15/68—Automatic cassette changing arrangements; automatic tape changing arrangements
    • G11B15/6805—Automatic cassette changing arrangements; automatic tape changing arrangements with linearly moving rectangular box shaped magazines
    • G11B15/6815—Automatic cassette changing arrangements; automatic tape changing arrangements with linearly moving rectangular box shaped magazines in horizontal direction
    • 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
    • G11B15/02—Control of operating function, e.g. switching from recording to reproducing
    • G11B15/05—Control of operating function, e.g. switching from recording to reproducing by sensing features present on or derived from record carrier or container
    • G11B15/093—Control of operating function, e.g. switching from recording to reproducing by sensing features present on or derived from record carrier or container by sensing driving condition of record carrier, e.g. travel, tape tension
    • 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
    • G11B15/02—Control of operating function, e.g. switching from recording to reproducing
    • G11B15/16—Control of operating function, e.g. switching from recording to reproducing by sensing presence, absence or position of record carrier or container
    • 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
    • G11B15/675—Guiding containers, e.g. loading, ejecting cassettes
    • G11B15/68—Automatic cassette changing arrangements; automatic tape changing arrangements
    • G11B15/6895—Automatic tape changing arrangements

Definitions

  • the primary object of this invention is to provide a tape-detecting device of simple construction for detecting travel and standstill of the tape.
  • Another object of this invention is to provide a tape-detecting device for detecting the presence of the tape.
  • Still another object of this invention is to provide a tape-detecting device for detecting the combination of the travel, standstill and presence of the tape.
  • FIG. 1 is a schematic diagram showing a tape-detecting device of this invention and its general arrangement, for explaining the invention
  • FIG. 2 is a side view of the principal part of the tape-detecting device
  • FIG. 3 is an enlarged cross-sectional view of an assembly of a pinch roller and a capstan illustrated in FIGS. 1 and 2;
  • FIG. 4 is a schematic diagram of one example of an electric circuit including the tape-detecting device of this invention.
  • FIG. 5A is a schematic diagram of a modified form of the electric circuit in accordance with another example of this invention.
  • FIG. 5B is a graph for explaining the operation of the example depicted in FIG. 5A;
  • FIGS. 6A and 68 to 10A and 10B are enlarged cross-sectional views of other modified forms of the assembly of the pinch roller and capstan of this invention.
  • FIG. 11 is a schematic diagram showing a modification of the contact of a brush with the pinch roller
  • FIG. 12 is a schematic diagram, similar to FIG. 5A, showing the electric circuit in accordance with another example of this invention.
  • FIG. 13 is a schematic diagram showing another example of this invention.
  • FIGS. 14 and 15 are schematic diagrams showing other examples of this invention.
  • FIG. 16 is a waveform diagram, for explaining the operation of the device depicted in FIG. 13.
  • FIG. 17 is a schematic diagram showing another example of this invention.
  • Reference numeral 1 indicates a bracket fonned of a conductive material and 2 a pinch roller which is rotatably mounted on the bracket I by a conductive pin or shaft 3.
  • the pinch roller 2 is made up of a columnar conductive metal member 2a rotatably mounted on the pin 3 an a roller member 2b formed of a resilient material such as rubber and fixedly mounted on the periphery of the columnar metal member 2a, as depicted in FIG. 3. If necessary. a bushing 2c may be interposed between the columnar member 2a and the roller member 2b.
  • the bracket I. the shaft 3 and the columnar member 2a may be regarded as constituting an electrically connected circuit.
  • insulating members 2a as of Bakelite or a plastic material are separately embedded in one end face of the columnar member 2a of the pinch roller 2 (in FIG. 1 in the face lying on the sheet of the drawings or in FIG. 3 in the left-hand face) in such a manner that the conductive material of the columnar member and the insulating material are alternately arranged on that end face of the columnar member 2a.
  • the insulating members 2a are need not always be embedded in that end face but may be deposited thereon. Further, it is also possible to form void areas in that end face at those places corresponding to the insulating members 2a without specially providing them.
  • Reference numeral 6 indicates a pin by means of which the bracket 1 is pivoted to a fixed portion, though not shown.
  • Reference numeral 7 designates a spring stretched between the fixed portion (not shown) and the bracket 1 for suitably biasing the latter, by which the pinch roller 2 supported by the bracket 1 is caused to press a magnetic tape T against a capstan 8 at a suitable pressure.
  • Reference numerals 9 and 10 respectively represent a take-up and a rewinding reel for the magnetic tape T, 11 and 12 guide rollers and 13 a magnetic head.
  • Reference numeral I in the figure indicates an electronic circuit block for AC amplification or eliminating a DC component and its input side is connected to the brush 4.
  • Reference numeral II designates a circuit for rectifying the output of the electronic circuit block I and III a switching circuit by means of which an output circuit having a load such as a relay or the like is switchingly controlled with the signal derived from the rectifier circuit II.
  • the columnar conductive member 2a is biased relative to a reference potential (for example, the earth potential), so that a rectangular wave or an AC signal and a DC component superimposed on each other are supplied from the brush 4 to the electronic circuit block I to remove the DC component and only the AC component is rectified by the rectifier circuit II to derive therefrom a DC output.
  • a reference potential for example, the earth potential
  • circuits I, II and III shown in FIG. 4 need not always be limited specifically thereto and may be suitably changed with the scope of attainment of the abovedescribed object and, further, the circuit elements may also be increased or decreased in number as desired.
  • roller member 2b of the pinch roller 2 depicted in FIG. 1 is formed of a conductive rubber in such a shape as shown in FIGS. 6A and 6B and in that both the capstan 8 and the bushing 20 are made of a conductive material.
  • the bracket 1, the shaft 3, the columnar member 2a and the roller member 2b may be regarded as constituting an electrically connected circuit,
  • FIG. 5A shows an electrically equivalent circuit, for explaining the tape-detecting operation of the tape-detecting device having the pinch roller assembly shown in FIG. 6.
  • FIG. SA the same reference numerals as those in FIGS. 1 and 6 indicate similar elements and in the figure reference character r represents the internal resistance of the roller member 2b, 1' the contact resistance between the capstan 8 and the roller member 2b and R, R, and R suitable resistors and a voltage V is impressed between the bracket 1 and the conductive capstan 8.
  • r represents the internal resistance of the roller member 2b, 1' the contact resistance between the capstan 8 and the roller member 2b and R, R, and R suitable resistors and a voltage V is impressed between the bracket 1 and the conductive capstan 8.
  • the brush 4 is in contact with (a) the insulating member 2a or (b) the columnar conductive member 2a. Consequently, the voltage across the resistor R is either V and V 3. Further, when the tape T does not exist between the capstan 8 and the pinch roller 2, they are electrically connected to each other. (e) Accordingly, if the brush 4 is in contact with the insulating member 2a, the resistor R and (r r) are connected in parallel with each other and the resistor R, is connected to the parallel connection in series, thereby to impress the voltage V across the circuit. As a result of this, the voltage V across the resistor R is given by the following equation.
  • the voltage across the resistor R is a kind of rectangular wave or an alternating current such that 0.435 and 0.416 volts alternate as indicated by the curve [1 in FIG. 5B.
  • this invention employs as signal-detecting means the combination of the capstan and the pinch roller rotating irrespective of the condition of the tape, instead of deriving a signal output from the reel shaft or the like as in the prior art, so that the device of this invention is free from the influences of slackness or winding condition of the tape on the reel shaft. Further, since no variation is caused in the revolving speed of the reel which results from a difference in diameter of the tape winding at the outer and inner convolutions thereof, an output signal of a constant frequency can be produced at all times, and accordingly the rising time constant of the control operation can be extremely reduced without fail.
  • FIGS, 7A and 7B illustrate another modification of the tapedetecting device of this invention.
  • the width W of the contact area of the pinch roller 2 with the capstan 8 or the tape T is selected greater than that W of the tape T and the roller member 21) of the pinch roller 2 is made up of a ring-shaped conductive rubber member 2b, and ring-shaped nonconductive rubber members 2b, and 2b,, griping therebetween the member 2b,.
  • the width W" of the conductive rubber member 2b is selected smaller than that W of the tape T so that when the tape T exists between the pinch roller 2 and the capstan 8 the conductive rubber member 2b, does not make direct contact with the capstan 8 (refer to FIG. 7A).
  • the pinch roller 2 makes contact with the capstan 8 at its nonconductive rubber members 2b and 2b;,, namely outside of the marginal edges of the tape T, thereby to further stabilize the travel of the tape T.
  • the tape T does not lie between the capstan 8 and the pinch roller 2
  • the latter is electrically con nected through its conductive rubber member 2b, as illustrated in FIG. 7B.
  • FIGS, 8A and 8B ring-shaped recesses or grooves 20, and 20 are formed between the conductive rubber member 2b, and the nonconductive rubber members 212 and 2b,, to ensure insulation between the capstan 8 and the pinch roller 2 (in the presence of the tape T therebetween).
  • the other arrangements are the same as those in the example of FIGS. 7A and 7B.
  • the roller member 2b of the pinch roller 2 is formed with a ring-shaped conductive rubber member 2b, and
  • a nonconductive rubber member 2b and the entire surface of one portion of that area of the capstan 8 contacting the conductive rubber member 2b is coated with an insulating material 8a such as ceramics, plastics or the like.
  • the width W of the contact area of the pinch roller 2 with the capstan 8 or the tape T is selected greater than that W of the tape T to stabilize the travel of the tape T.
  • the roller member 2b of the pinch roller 2 is formed of a' conductive rubber but the width W of its contact area with the capstan 8 and the tape T is selected greater than that W of the tape T to stabilize the travel of the tape T. While, the roller member 2b of the pinch roller 2 makes contact with the capstan 8 outside of the both marginal edges of the tape T but ring-shaped insulating members 8a and 8b are formed on the corresponding peripheral surfaces of the capstan 8. In this case the distance (or width) W' between the both insulating members 8a and 8b is selected shorter than the width W of the tape T. With such an arrangement, when the tape T exists between the pinch roller 2 and the capstan 8, they are electrically insulated from each other as depicted in FIG. 10A and when the tape T does not lie therebetween they are electrically connected to each other as shown in FIG. 1013.
  • FIG. 11 illustrates another example of this invention in which the brush 4 and the columnar member 2a make contact with each other in a different manner from those in the foregoing examples.
  • the brush 4 makes contact with the columnar member 2a not at its end face but at the periphery thereof.
  • the insulating members 2a are discontinuously embedded in or deposited on the end face of the columnar member 2a in the same manner as in the foregoing examples, so that the brush 4 makes alternate contact with the columnar member 2a and the insulating members 2a. Accordingly, this example is exactly the same in operation as the foregoing ones.
  • the bracket 1 described above may be formed by molding from an insulating material such as plastic or like material, in which case the shaft 3 may be used as one terminal and the spacers 5 and 5' may be thereby left out.
  • FIG. 5 utilizes for detection of the presence of the tape the effect of a parallel resistance due to the continuous contact of the conductive pinch roller with the capstan.
  • FIG. 12 With reference to the block diagram of FIG. 12 a description will be given of another modification of this invention.
  • reference numeral I indicates an electronic circuit block for AC amplification or eliminating a DC component, II, a rectifier circuit block for rectifying the output of the electronic circuit block 1,, I, an amplifier circuit block which is actuated by a potential produced by the contact of the pinch roller with the capstan, II, a rectifier circuit block for rectifying the output of the amplifier circuit block I,', and III a signal converter which is incorporated in such a manner that the output signals of the rectifier circuit block II or II, representative of the standstill and absence of the tape are in phase with each other.
  • the signal converter Ill is of the type which blocks a DC signal supplied from the rectifier circuit block II but produces a DC signal in the absence of the DC signal derived from the rectifier circuit block II,.
  • the signal converter III may be placed at a stage following the rectifier circuit block II, or II,'.
  • Reference numeral IV designates a signal mixer circuit block for mixing the signals derived from the signal converter III, and the rectifier circuit block II,, and V a switching circuit block for switchingly controlling an output circuit having a relay and the like as loads with a signal derived from the signal mixer circuit block IV.
  • the conductive columnar member 2a and the roller member 2b are biased relative to a reference potential (for example. the earth potential), so that a rectangular wave or AC signal and a DC component superimposed on each other are supplied from the brush 4 to the electronic circuit block I to remove the DC component and only the AC component is rectified by the rectifier circuit block II, to derive therefrom a DC output.
  • a reference potential for example. the earth potential
  • the roller member 2b and the capstan 8 are continuously or intermittently engaged with each other.
  • a DC- or AC-like signal is supplied to the amplifier circuit block I. to be amplified and then rectified by the rectifier circuit block II, and, in either case, a DC output is derived from the rectifier circuit block II,'.
  • the rectifier circuit block II is designed to have a phase permitting the passage therethrough of the input DC signal.
  • the signal converter circuit [II is provided at the stage following the rectifier circuit block II and the control switching circuit is actuated through the signal mixer circuit or OR-gate circuit IV in a manner to achieve the same operation in either case.
  • control operation can be achieved by increasing the amplification degree of the amplifier circuit block 1,, thus ensuring stable and highly sensitive control operation.
  • the rising time constant of the rectified output of the rectifier circuit block II can be diminished relative to that of the rectifier circuit block Il so that in the absence of the tape T the control circuit can be actuated in a moment irrespective of the numbers of the conductive members and the insulating members 2a and 2a, thereby the ensure rapid operation.
  • circuit blocks 1,, II,, III,, 1,, II,', III,, IV and V shown in FIG. 12 need not always be limited specifically thereto and may be suitably changed within the scope of attainment of the above-described objects and, further, the circuit elements may also be increased or decreased in number as desired.
  • FIG. 13 illustrates a further modification of this invention, in which similar elements to those in the foregoing examples are identified by the same reference numerals.
  • the pinch roller 2 consists of a pinch roller proper 2d formed of an insulating material such as a nonconductive rubber, a discontinuous conductive member 2e consisting of a plurality of tabs formed of conductive rubber embedded in the peripheral surface of the pinch roller proper 2d on its upper marginal portion at regular intervals, each tab being wider than the width of the contact area of the pinch roller 2 with the capstan 8, and a belt-shaped continuous conductive member 2f embedded in the pinch roller proper 2d con-' tiguously to the discontinuous conductive member 2e.
  • the belt-shaped continuous conductive member 2f is positioned at such a location as to be out of contact with the capstan 8 in the presence of the tape T between the pinch roller 2 and the capstan 8 as shown in FIGS. 13 and 14 and to be in contact with the capstan 8 in the absence of the tape T therebetween.
  • FIG. 15 shows still a further modified form of this invention which is identical in construction with that of FIG. 13 except in that the continuous and discontinuous members 2f and 2e are respectively embedded in the pinch roller proper 2d so that they interconnect and connect with the pin 3 in the body of the pinch roller proper 2d but do not interconnect at the surface thereof.
  • reference numeral indicates a DC power source inserted between the pinch roller 2 and the capstan 8.
  • the circuit constituted by the pinch roller 2, the capstan 8 and the DC power source 15 is connected to an AC amplifier 16, which is, in turn, connected to a rectifier circuit 17
  • Reference numeral 18 designates a relay coil connected to the rectifier circuit 17.
  • a movable contact piece 19 of the relay coil 18 is to open and close the power source of a deck.
  • the resulting electric signal is amplified by the AC amplifier 16, whose output is rectified by the rectifier circuit 17 into a direct current, which is then fed to the relay coil 18 to close its movable contact piece 19, thus maintaining, for example, recording or playback of the tape.
  • the capstan 8 races or runs idle and the pinch roller 2 stops rotation, in which case either one or both of the pinch roller proper 2d and the discontinuous conductive member 2e of the pinch roller 2 make contact with the capstan 8, so that such a rectangular wave as depicted in FIG. 16 is not generated. Consequently, the rectifier circuit 17 produces no output and the contact piece 19 of the relay coil 18 is opened to actuate a tape control device.
  • the present invention has been described in connection with the cases where the rotary member is a pinch roller and the conductive member is a capstan, it is also possible to achieve similar automatic tape control by separately providing on the deck plate of a tape recorder a conductive member and a rotary member having provided thereon the aforementioned discontinuous and continuous conductive members and driving the tape gripped between the rotary and conductive members to produce the aforementioned rectangular wave.
  • the discontinuous and continuous members may be provided in various shapes other than those depicted in FIGS. 13 and 15.
  • the discontinuous member 22 may be provided in the form of a resilient conductive piece, which gets into or out of contact with the conductive member to produce the rectangular wave.
  • the tape-detecting device of this invention does not derive any signal output from the reel shaft or the like as practised in the prior art but instead employs as signal-detecting means the combination of the rotary member such as a pinch roller with the conductive member such as a capstan which rotate irrespective of the condition of the tape, so that the device of this invention is not affected by the slackness of the tape or its winding condition on the reel shaft or variations in the revolving speed of the reels due to the difference in the diameter of the tape winding at the inner and outer convolutions thereof.
  • This provides an output signal of substantially constant frequency at all times, and hence greatly reduces the riding time constant of the control operation and ensures the operation.
  • the present invention provides a tape-detecting device which is relatively simple and compact in construction, reliable in operation and inexpensive.
  • a tape-detecting device comprising a discontinuous conductive member, a conductive member making contact therewith, both said members mounted for rotation on opposite sides of the tape in accordance with the travel of a tape and a power source for applying a voltage between the discontinuous conductive member and the conductive member, in which an electric signal is derived from between the discontinuous conductive member and the conductive member when they are both rotating in accordance with the travel of a tape.
  • a tape-detecting device comprising a pinch roller consisting of an outer cylindrical member formed of an elastic material and an inner cylindrical member formed of a conductive material, in which a conductive piece is provided in a manner to make intermittent contact with one end face of the inner cylindrical member and a voltage impressed between the inner cylindrical member formed of the conductive material and the conductive piece making intermittent contact therewith, thereby to derive from therebetween an electric signal corresponding to their intermittent contact.
  • a tape-detecting device as claimed in claim 1 which includes a tape contact portion formed of a conductive material and provided on the outer peripheral surface of the discontinuous conductive member and a conductive contact portion placed opposite to the tape contact portion.
  • a tape-detecting device as claimed in claim 8 wherein ring-shaped grooves are formed along the boundaries between the conductive area and the areas formed of the insulating material.
  • a tape-detecting device as claimed in claim 7 wherein the tape contact portion is made up of an area fonned of a conductive material and an area formed of an insulating material and an insulating material is provided on the conductive tape contact area of the tape contact portion placed opposite to the tape contact member.
  • a tape-detecting device as claimed in claim 7 wherein the tape contact portion is wider than a tape, two insulating members are provided on the conductive tape contact portion placed opposite to the tape contact portion and the distance between the two insulating members is smaller than the width of the tape.
  • a tape-detecting device comprising a discontinuous conductive member mounted on a conductive shaft, a resilient member placed on the outer peripheral surface of the discontinuous conductive member, a conductive member disposed to make contact with the discontinuous conductive member.
  • means for supporting the conductive shaft the supporting means further supporting the conductive member, means for impressing a voltage between the conductive member and the conductive shaft, and means for deriving from therebetween an electric signal in accordance with the relative rotation between the discontinuous conductive member and the conductive member.

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US48025A 1969-06-27 1970-06-22 Tape-detecting device for tape recorders Expired - Lifetime US3633804A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP44050768A JPS5122368B1 (OSRAM) 1969-06-27 1969-06-27
JP5076769 1969-06-27
JP45000135A JPS516528B1 (OSRAM) 1969-12-29 1969-12-29

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US3633804A true US3633804A (en) 1972-01-11

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US48025A Expired - Lifetime US3633804A (en) 1969-06-27 1970-06-22 Tape-detecting device for tape recorders

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GB (1) GB1310178A (OSRAM)
NL (1) NL7009499A (OSRAM)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4268182A (en) * 1976-09-28 1981-05-19 Citizen Watch Co., Ltd. Device for detecting travel condition of inkribbon for printers
US20210365075A1 (en) * 2018-09-04 2021-11-25 Hewlett-Packard Development Company, L.P. Hinge switches

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3148814A (en) * 1961-02-27 1964-09-15 Studer Willi Method for automatically stopping the drive of tape-type record carriers
US3370286A (en) * 1964-05-12 1968-02-20 Olympia Werke Ag Apparatus for monitoring the feeding of tapelike record carriers
US3554343A (en) * 1969-02-26 1971-01-12 Union Carbide Corp Motion detecting method and apparatus
US3564170A (en) * 1969-03-22 1971-02-16 Licentia Gmbh Multiple sheet removal detector employing electrically contacting rollers

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3148814A (en) * 1961-02-27 1964-09-15 Studer Willi Method for automatically stopping the drive of tape-type record carriers
US3370286A (en) * 1964-05-12 1968-02-20 Olympia Werke Ag Apparatus for monitoring the feeding of tapelike record carriers
US3554343A (en) * 1969-02-26 1971-01-12 Union Carbide Corp Motion detecting method and apparatus
US3564170A (en) * 1969-03-22 1971-02-16 Licentia Gmbh Multiple sheet removal detector employing electrically contacting rollers

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4268182A (en) * 1976-09-28 1981-05-19 Citizen Watch Co., Ltd. Device for detecting travel condition of inkribbon for printers
US20210365075A1 (en) * 2018-09-04 2021-11-25 Hewlett-Packard Development Company, L.P. Hinge switches

Also Published As

Publication number Publication date
NL7009499A (OSRAM) 1970-12-29
DE2031715A1 (OSRAM) 1971-02-04
DE2031715B2 (de) 1973-01-11
GB1310178A (en) 1973-03-14

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