US3564158A

US3564158A - Tape lifter

Info

Publication number: US3564158A
Application number: US739371A
Authority: US
Inventors: Charles R Horton
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1968-06-24
Filing date: 1968-06-24
Publication date: 1971-02-16
Anticipated expiration: 1988-02-16
Also published as: GB1255727A; FR2014179A1; CA921063A; DE1931754A1

Abstract

A technique is disclosed for separating a web from its supporting member without movement of the supporting member. A number of web-engaging rods are disposed within the supporting member close to the supporting surface traversed by the web. When actuated, the rods protrude from the supporting surface and are interposed between the web and its supporting surface. This causes the web to be lifted or separated from the supporting surface. The amount of separation and its extent along the supporting surface may be determined by the orientation and amount of movement of the web-engaging rods.

Description

226/5X 179/100.2(T) lwumura 2,972,439 2/1961 Cunningham 226/5X 3,071,301 l/1963 Benson.... 3,207,855 9/1965 Barger..... 3,042,753 7/1962 179/100.2(C)

Primary ExaminerRichard A. Schacher Att0rneyEdward J. Norton Charles R. Horton Beverly, NJ. [21] Appl. No. 739,371

June 24, 1968 [45 Patented Feb. 16, 1971 RCA Corporation 8 Claims, 7 Drawing Figs.

United States Patent [72] Inventor [22] Filed 73 Assignee [54] TAPELIFIER ABSTRACT: A technique is disclosed for separating a web from its supporting member without movement of the supporting member. A number of web-engaging rods are disposed within the supporting member close to the supporting surface traversed by the web. When actuated, the rods protrude from the supporting surface and are interposed between the web and its supporting surface. This causes the web to be lifted or separated from the supporting surface. The amount of separation and its extent along the supporting surface may be deterunt of movement of the mined by the orientation and amo web-engaging rods.

2,654,808 10/1953 Olsson..........................

PATENIED FEB 1 s 197i SIEUIUFZ INVENTOR Charles R. Horlon BY $Lwzw1% 1 II'TOIUEY PATEN'TED 'FEBI 6 I971 SHEET 2 BF 2 Charles R Ho l izr l BY 5mm TAPE LIFTER It is generally desirable in" tape recording devices, to minimize wear of the record medium during nonrecording operating modes. This is accomplished by preventing contact between the record medium and the mandrel and/or the transducer heads during these modes. It is particularly important in video recording apparatus, where there is abrasive action between the record medium and a high velocity rotational headwheel or tape mandrel.

Many techniques in the prior art have been utilized to perform this function. However, the prior art systems find it necessary to employ extensive mechanical devices for movement of the tape supporting structure or transducer heads, or require elaborate air pressure and vacuum systems for movement of the record medium. These devices by their nature are complex, difficult to fabricate and hence are costly. The present invention accomplishes record medium conservation by provision of an arrangement of self contained mechanical fingers in the tape support structure. The present invention is easy to implement and actuate, and eliminates the need for the complicated equipment used in the prior art.

It is therefore an object of the present invention to provide an improved lifting system for minimizing wear of a record medium. I

Another object is to provide a record medium lifting device which is applicable to rotational and stationary tape support structures.

A further object is a method of controllably separating the record medium from the support structure and the transducer heads, without movement of either'of the latter devices.

Briefly, in accordance with the present invention at least one plunger is provided for movement into the vicinity between the web of material or record medium and the surface of the member it traverses. The plungers are disposed within the member such that a linear axial actuating movement produces a radial movement of the plungers. This causes the plungers to be interposed between the record medium and the supporting member thereby causing a separation or lifting of the record medium.

FIG. 1 is a elevation view partly in section of a first embodiment of the invention.

FIG. 2 is a sectional view of the embodiment of FIG. 1 taken on the line 2-2 of FIG. 1.

FIG. 3 is a further elevation view partly in section of the embodiment of FIG. 1.

FIG. 4 is a sectional view on the line 4-4 of FIG. 3.

FIG. 5 is a diagrammatic view showing a feature of the invention. I

FIG. 6 is an elevation view partly in section of a second embodiment according to the invention.

FIG. 7 is a diagrammatic view showing a further feature of the invention.

If reference is made to FIG.'1, there is shown a stationary hollow cylindrical mandrel or drum 8 having a lower section 9 which is coaxial with an upper. section 10. A headwheel 11 is coaxially mounted for rotation between the mandrel sections 9 and by the bearing 13. A web of material or record medium I4 is wrapped in contacting relation partially about the mandrel 8. The record medium 14 traverses at least the portion of sections 9 and 10 which are adjacent to the headwheel 11. Magnetic transducers 12 are mounted on the periphery of the headwheel 11 so as to contact the record medium 14. The mandrel section 9 has a series of apertures 15 between the interior hollow portion and the portion of the peripheral surface of the mandrel 9 which is traversed by the record medium 14. The apertures 15 are inclined to the longitudinal axis of the mandrel 8 and extend radially outward through the wall of mandrel section 9. The apertures 15 intersect the peripheral surface of mandrel portion 9 at a point adjacent to the headwheel 11. Located within the hollow portion of the mandrel section 9, are a series of resilient rods or plungers 16. The plungers 16 are preferably formed of a nonmagnetic plastic material or a flexible nonmagnetic metal. Plungers 16 are shaped for slidable movement through the apertures 15. The

upper end of plungers 16, which are shaped for noninjurious contact with the record medium 14, extend partially through the aperture 15. The upper end of the plungers 16 are preferably rounded, or at least have a contour which is devoid of sharp edges, which could scratch, tear or otherwise injure the medium 14 upon contact. The lower end of the plungers 16 are secured to an actuating mechanism 17, which is slidably mounted within the mandrel section 9 for movement in the direction denoted by the arrow 19. Actuating mechanism 17 is connected to a controllable prime mover element 18, which may for example be an electrically operated solenoid.

The sectional view of FIG. 2 clarifies the interrelation of the like numbered elements of FIG. 1. FIG. 2 shows the record medium 14 encircling a portion of mandrel 8 in contacting relation. There is also shown the apertures 15 spaced about the portion of the mandrel 8 traversed by the record medium 14. The plungers 16 which are secured to actuating member 17, extend into and partially through the apertures 15.

The operation of the embodiment of FIG. 1 can best be understood by a consideration of FIGS. 3 and 4 in conjunction with FIG. 1. The structure of FIGS. 3 and 4 are identical to that shown in FIG. 1, and the same reference numerals identify the corresponding elements. In the operation of the embodiment disclosed in FIGS. 1 and 3, the mandrel 8 is stationary while the headwheel 11 is rotated at a high speed. The present invention is operable where the record medium 14 is disposed about the mandrel 8, is either stationary or moving relative to the mandrel 8. The drive means for rotation of headwheel l1 and movement of the medium 14 are not shown, since several means are well known in the art for accomplishing this. In FIG. 1, the tape lifting plungers 16 are shown in the deactivated position. That is, they are disposed in close proximity but in noncontacting relation to the record medium 14. Thus the record medium 14 is in contact with the mandrel sections 8 and 9 and the magnetic transducers 12 on the headwheel 11. When it is desired to lift the record medium 14, the prime mover element 18 is activated causing the actuator 17 to move in an upward direction toward the headwheel 11. In response, the plungers 16 which are secured to actuator 17 move upwardly and radially outwardly through the apertures 15. The upper end of plungers 16 contact the record medium 14, and are interposed between the record medium 14 and a surface of the mandrel 8. The distance plungers 16 are moved is made sufficient to cause at least those portions of the record medium 14 which are adjacent to the headwheel 11 to be separated from the headwheel 11 and the proximate portions of the mandrel sections 9 and 10.

This result is disclosed in FIG. 3, which shows the embodiment of FIG. 1 in the activated position. In FIG. 3 the plungers 16 are shown in the activated or extended position, in which they are interposed between the record medium 14 and the mandrel 8. This causes the record medium 14 to be lifted away from the peripheral surface of mandrel-8. It is clear from FIG. 3, that the amount of lift and the extent separation of record medium 14 from the headwheel lland mandrel 8, may be varied by controlling the distance traveled by plungers I6 when they are activated.

The sectional view of FIG. 4 clarifies the interrelation of the like numbered elements of FIG. 3. FIG. 4 shows the disposition of apertures 15 about the portion of the mandrel 8, which is encircled by the record medium 14. The plungers 16 secured to actuator 17 extend through the apertures 15, causing a portion of the record medium 14 to be in noncontacting relation to the mandrel 8.

If reference is made to FIG. 5, there is shown a hollow cylindrical mandrel or drum 22. The mandrel 22 is mounted for rotation in bearings 20. Magnetic transducers 21 are mounted in the peripheral surface of the mandrel 22. A record medium 14 is wrapped in contacting relation partially about the mandrel 22, including the portion containing the magnetic transducers 21. The mandrel 22 has a series of spaced apertures 15, between the interior hollow portion and the portion of the mandrel surface which is traversed by the record medium 14. The apertures are inclined to the longitudinal axis of the mandrel 22, and extend radially outward through the mandrel wall. The apertures 15 intersect the peripheral surface of mandrel 22, at a point adjacent to the magnetic transducers 21. Located within the hollow portion of the mandrel 22, are a series of straight rigid rods or plungers 23 preferably formed of a nonmagnetic material. The plungers 23 are shaped for slidable movement through the apertures 15. The upper end of plungers 23, which are shaped for noninjurious contact with the record medium 14, extend into the apertures 15. The upper ends of plungers 23 are preferably rounded or at least have a contour which is devoid of sharp edges which could scratch, tear or otherwise injure the medium 14 upon contact. The lower end of the plungers 23, are rounded for slidable movement relative to the surface of an actuating mechanism 24. The actuating member 24 is slidably mounted within the mandrel 22, and has a frustoconical surface which is in contacting relation with the lower ends of the plungers 23. The actuating member 17 is connected to a controllable prime mover element 18, which again may for example be an electrically operated solenoid.

In the operation of the embodiment of FIG. 5, the mandrel 22, transducers 21 and the plunger rotate as a unit at high speed. The actuating member 24 and prime mover may also be made to rotate with the mandrel 22. The present invention is operable where the record medium 14' which is disposed about the mandrel 22, is either stationary or moving relative to the mandrel 22. The drive means for rotation of the mandrel 22 and movement of the medium 14 are not shown, since such means are well known in the art. On command, the prime mover element 18 causes the actuator 24 to move upwards within the mandrel 22. The upward movement of the frustoconical surface of actuator 24, causes an upward and radially outward movement of the rigid plungers 23 through apertures 15. The frustoconical surface of the actuator 24 is provided, since is permits efficient movement of the plungers 23 in response to linear movement of actuator 24. That is, the frustoconical shape results in a linear function of force versus displacement, between the actuator 24 and plungers 23. It is to be understood however, that other shapes may also be employed for actuator 24 consistent with the force versus displacement characteristic of the prime mover 18. For example, the actuator 24 may have a spherical curvature, which results in a nonlinear function of force versus displacement between actuator 24 and plungers 23. When the plungers 23 are caused to protrude from the apertures 15 by the upward movement of actuator 24, the plungers 23 are interposed between the mandrel 22 and record medium 14. The result is a lifting or separation of at least a portion of the width of the record medium from the mandrel 22. This separation is present about the portion of the mandrel traversed by the record medium 14.

If reference is made to FIG. 6, there is shown diagrammatically a feature of the present invention. FIG. 6 shows a mandrel 25 which has a record medium 14 wrapped around the mandrel 25 covering the angle B. Apertures 15 are provided at the angle intervals or over the angle B. As shown in FIG. 5, the apertures 15 are inclined to the mandrel's longitudinal axis by the angle 0. It is to be understood that the angles [3, a and 0 may be varied with the optimum values being determined by the requirements of a particular application of the invention. For example the angle B may be made greater than 360 if the aperture are arranged axially along the mandrel in a path that defines a helix or a series of spiral rings. This would allow the web or recording medium to be supported over a larger surface area. In addition various values for the angle 0 may be specified to control the extent of movement of the plungers and the point of their imposition with respectto the transducer heads. This in turn determines the amount of lift or separation of the web and what portion of the total width of the web is separated.

If reference is made to FIG. 7, there is shown a further feature which forms a part of the present invention. FIG. 7 shows a hollow mandrel 27 having a series of apertures 15 about the mandrel 27, between the hollow portion and its peripheral surface. In the embodiment of FIG. 7, the rods or plungers 28 in adjacent apertures are joined at the end adjacent to the peripheral surface of mandrel 27. The other end plungers 28 engage the actuating member 26. Alternatively the plungers 28 may be continuous U-shaped wherein the respective legs project through adjacent apertures 15 and engage actuator 26. The plungers 28 may be resilient or rigid. Thus in the embodiment of FIG. 7, n numbers of plungers 28 are formed for Zn number of holes.

It is to be understood that various combinations of the disclosed features of the invention may be utilized. For example the rigid plungers 23 of the rotating mandrel 22 of the embodiment of FIG. 5, may be utilized in the stationary mandrel 8 embodiment of FIGS. 1. Likewise, the resilient plungers 16 of the embodiment of FIG. 1 may be employed in the rotating mandrel embodiment of FIG. 5-. In addition the feature disclosed in FIG. 7 is applicable to the embodiment of FIGS. 1 and 5. It is also to be noted, that the present invention is applicable for various methods of wrapping the record medium about the mandrel. That is, the wrap or record medium 14 may be normal to the longitudinal axis of the mandrel as shown in FIG. 1, or skewed with respect to the longitudinal axis of the mandrel as shown in FIG. 5. The principles of the present invention are also applicable where the relation of the record medium and the transducer heads is essentially orthogonal. For example, the invention can be utilized where the transducer heads scan the record medium transversely such as in quadruplex recording systems.

Iclaim:

l. A device for lifting a web which passes about the periphery of a drum comprising, a drum having at least one aperture therein communicating with a portion of said drum periphery, mechanical means disposed within said aperture adapted to engage said web so as to cause said web to be separated from at least a portion of said peripheral surface of said drum, and means for controlling said mechanical means mounted for movement coaxially of said drum.

2. A tape-lifting device for use where a record medium passes around a portion of the periphery of a drum comprising, a drum having at least one aperture therein communicating with a portion of said drum periphery traversed by said record medium, a plunger slidably mounted within said aperture said plunger being caused to move in a radial direction engaging said record medium in response to an actuating member mounted for movement coaxially of said drum.

3. The device of claim 2 wherein, said plunger is a resilient rod.

4. A tapelifting device for use where a record medium passes around a portion of the periphery of a drum, said drum having at least two apertures therein communicating with a portion of said drum periphery subtended by said record medium, a plunger slidably mounted in each of said apertures, said plungers being joined at an end which is adapted to engage said record medium, and means for urging said plungers into contacting relation with said record medium.

5. In combination:

a mandrel having at least one aperture therein communicating with the peripheral surface of said mandrel;

at least one transducer head mounted in said peripheral surface of said mandrel;

a record medium traversing said apertured portion of said mandrel and said transducer head; and

mechanical means, adapted to engage said medium,

disposed within said aperture, said means when actuated protruding from said aperture engaging said medium causing said medium to be separated from said mandrel.

6. In combination with an apparatus wherein a record medium passes peripherially about the portion of a mandrel having at least one transducer head mounted therein, the improvement comprising:

a mandrel having at least one aperture therein communicating with the peripheral surface traversed by said record medium;

mechanical means adapted to engage said record medium disposed within said aperture; and

means for urging said mechanical means into contacting relation with said record medium to cause said medium to be separated from at least the portion of said mandrel adjacent to said transducer head.

7. A tape-lifting device for use where a record medium traverses a portion of the periphery of a mandrel, comprising a hollow cylindrical mandrel having a plurality of apertures extending between said hollow portion and the surface of said mandrel, said apertures being inclined to the longitudinal axis of said mandrel and being spaced at intervals about at least the traversed portion of the periphery of said mandrel, plunger means slidably mounted within said apertures one end of which are adapted to engage said record medium, and means for actuating said plunger means to cause all of said plunger means to simultaneously engage said record medium whereby at least a portion of said record medium about said mandrel is disposed in noncontacting relation to said mandrel.

8. The device of claim 7, wherein said plungers are rigid and said actuating means includes a contoured surface which is engaged by said plungers for controlled movement of said plungers through said apertures.

Claims

1. A device for lifting a web which passes about the periphery of a drum comprising, a drum having at least one aperture therein communicating with a portion of said drum periphery, mechanical means disposed within said aperture adapted to engage said web so as to cause said web to be separated from at least a portion of said peripheral surface of said drum, and meaNs for controlling said mechanical means mounted for movement coaxially of said drum.

3. The device of claim 2 wherein, said plunger is a resilient rod.

4. A tape-lifting device for use where a record medium passes around a portion of the periphery of a drum, said drum having at least two apertures therein communicating with a portion of said drum periphery subtended by said record medium, a plunger slidably mounted in each of said apertures, said plungers being joined at an end which is adapted to engage said record medium, and means for urging said plungers into contacting relation with said record medium.

5. In combination: a mandrel having at least one aperture therein communicating with the peripheral surface of said mandrel; at least one transducer head mounted in said peripheral surface of said mandrel; a record medium traversing said apertured portion of said mandrel and said transducer head; and mechanical means, adapted to engage said medium, disposed within said aperture, said means when actuated protruding from said aperture engaging said medium causing said medium to be separated from said mandrel.

6. In combination with an apparatus wherein a record medium passes peripherially about the portion of a mandrel having at least one transducer head mounted therein, the improvement comprising: a mandrel having at least one aperture therein communicating with the peripheral surface traversed by said record medium; mechanical means adapted to engage said record medium disposed within said aperture; and means for urging said mechanical means into contacting relation with said record medium to cause said medium to be separated from at least the portion of said mandrel adjacent to said transducer head.