US3674559A - Method of cleaning magnetic tape - Google Patents

Abstract

A METHOD AND APPARATUS FOR CLEANING MAGNETIC TAPE WHEREIN A CONTINUOUS LOOP OF MATERIAL HAVING A CUTTING EDGE IS ROTATED WHILE A FLAT SURFACE OF THE TAPE IS MOVED PAST AND IN CONTACT WITH THE CUTTING EDGE AT TWO LOCATIONS SO THAT THE SURFACE IS CLEANED. IN THE EMBODIMENT SET FORTH BELOW, THE LOOP IS INCLINED AT ONE LOCATION AT AN ACUTE ANGLE TO THE PATH OF TRAVEL OF THE TAPE IN ONE DIRECTION AND AT AN ACUTE ANGLE IN THE OTHERR DIRECTION AT THE OTHER LOCATION SO THAT PASSAGE OF THE TAPE HONES THE CUTTING EDGE. THE LOOP IS PREFERABLY TOTATED ABOUT TWO CAPSTANS AND ONE CAPSTAN CAN BE MOVED TOWARD THE OTHER AT THE SAME TIME THAT THE GUIDE MEMBERS WHICH DEFINE SLOTS AT THE TWO LOCATIONS SEPARATE FOR LOADING THE LOOP.

Description

July 4, 1972 Q WHYSONG ET AL 3,674,559

METHOD OF CLEANING MAGNETIC TAPE 2 Sheets-Sheet 1 Filed Jan, 28, 1971 TA'PZ JMQM AZQQJMAW ATTORNEYS July 4, 1972 o. c. WHYSONG ETAL 3,674,559

METHOD OF CLEANING MAGNETIC TAPE Filed Jan. 28, 1971 2 Sheets-Sheet 2 INVENTORS A .DflL E C. W V5 0 we #5555272. You/v6- ATTORNEYS United States Patent 3,674,559 METHOD OF CLEANING MAGNETIC TAPE Dale C. Whysong, Falls Church, Dale E. Leininger, Fairfax, and Herbert D. Young, Haymarket, Va., assignors to General Kinetics Incorporated, Reston, Va.

Filed Jan. 28, 1971, Ser. No. 110,574 Int. Cl. B08b 7/00 US. Cl. 134-9 2 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for cleaning magnetic tape wherein a continuous loop of material having a cutting edge is rotated while a flat surface of the tape is moved past and in contact with the cutting edge at two locations so that the surface is cleaned. In the embodiment set forth below, the loop is inclined at one location at an acute angle to the path of travel of the tape in one direction and at an acute angle in the other direction at the other location so that passage of the tape bones the cutting edge. The loop is preferably rotated about two capstans and one capstan can be moved toward the other at the same time that the guide members which define slots at the two locations separate for loading the loop.

BRIEF DESCRIPTION OF THE PRIOR .ART AND SUMMARY OF THE INVENTION The invention relates to a method and apparatus for cleaning magnetic tape.

Nodules of material tend to build up on magnetic tapes from use. These nodules are comprised of material which becomes dislodged from the tape, agglutinates and is ironed into the tape by compression on a reel or by travel over the usual members which guide and move the tape. These nodules, if left on the tape, have the effect of lifting the tape away from the reading head and accordingly altering the coupling between the tape and the head, with a resultant loss of signal at each nodule location. Accordingly, it is desirable at frequent intervals to clean the tape by removing the nodules and for many applications where any loss of information is unacceptable such tapes must be cleaned after each use.

One Way in which such tapes are now cleaned is by passing the fiat surface of the tape over the sharp cutting edge of a fixed blade, such as a razor blade, so that the blade scrapes the nodules from the tape as it passes the cutting edge. One considerable disadvantage with this approach, however, is that the cutting edge of the fixed blade wears rapidly and must be changed at frequent intervals, usually after each reel of material has passed the blade. Accordingly, a considerable amount of time is spent by skilled personnel in simply changing blades. Further, like all razor blades, blades of this type are somewhat dangerous to handle and can easily cause injury to the personnel who must handle them, if treated with less than great care.

Another scraping arrangement which has also been used in the past and which has been found to be more advantageous than a fixed blade comprises a solid disc which is rotated about a central axis with the flat surface of the tape moving over the top edge of the disc at one location, and subsequently over that same edge at another location. This arrangement has proved more satisfactory than a fixed blade, but the disc still needs to be replaced at frequent intervals and is still somewhat dangerous to handle.

The present invention relates to a tape cleaning device and method whereby a continuous closed, and preferably flexible, loop of material having a cutting edge is rotated about a fixed path, and at the same time the tape is moved ice across and in contact with the cutting edge of the blade at first and second locations so that foreign material on the surface of the tape is scraped away by the rotating edge of the loop. Further, according to a preferred embodiment of the invention as described below, the rotating loop is preferably inclined in one direction along the path of travel of the tape at the first location and in the opposite direction of the path of travel of the tape at the second location so that the tape in effecthones the cutting edge as it passes over it at the two locations.

Further, in the specific embodiment of the invention set forth below, the loop of material is rotated about two capstans and passes between two guide members as it travels from one capstan t0 the other at which it is inclined and at which it encounters the surface of the tape for cleaning. One of the capstans is driven by an electrical motor and the other capstan extends into a first bore in the housing on which the capstans and guide members are mounted. Extending into another bore substantially transverse to the first one is a manually operated member which is urged outwardly by a spring in that second bore and which attaches to the first capstan so that, by manually pushing the member into the bore against the urging of the spring, the non-driven capstan moves toward the driven capstan for simple and easy removal and replacement of the cutting loop. The guide members preferably include a fixed center guide member and two side guide members which each define a slot between the center guide member and that side guide member through which the loop passes and is inclined. The side guide members preferably extend through two more bores into the housing and contact the manually operated member as it moves inward with the non-driven capstan so that the two other guide members, which are urged together by a further spring, are thus separated to increase the width of the slots and also expedite the changing of a blade loop.

Many other objects and purposes of the invention will become clear from the following detailed description of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective view of the magnetic tape cleaner of this invention with a magnetic tape passing over the rotating loop of cutting material;

FIG. 2 shows a view of the inclined blade at one location with tape passing over it and being cleaned;

FIG. 3 shows a view of the inclined blade at the second location with the tape passing over it and being cleaned;

FIG. 4 shows a top view of the tape cleaner of FIG. 1;

FIG. 5 shows a partially cutaway side view of the tape cleaner of FIG. 1;

FIG. 6 shows a cutaway view of the tape cleaner of FIG. 5 along the lines 66; and

FIG 7 shows a cutaway view of the tape cleaner of FIG. 5.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to FIG. 1 which shows a perspective view of the novel tape cleaner 20 of this invention with a conventional magnetic tape 22 passing over the cutting edge of loop 24. The continuous loop 24 is preferably made of a thin, hardened, stainless steel band, for example, .001 inch, which is cut to a convenient length and the two ends electron beam welded together to form a flexible loop of homogenous steel. While the arrangement in FIG. 1 shows the device cleaning magnetic tape, it will, of course, be understood that it can be also used to clean other tape, such as uncoated acetate or polyester film.

Loop 24 is mounted between a driven capstan 28 and a non-driven capstan 30 and encounters the magnetic tape which is moving past loop 24 at two separate locations, labeled X and Y. Loop 24 is mounted so that the edge of the blade is inclined toward the tape as it approaches location X, shown in FIG. 2, and is inclined in the opposite direction as it approaches location Y, shown in FIG. 3. While tape 22 is moving across loop 24, loop 24 is slowly rotating so that tape 22 does not a wear a groove in the loop and accordingly it wears at a uniform rate over its entire length. Where the cutting edge of loop 24 contacts tape 22, an angle or, shown in FIGS. 2 and 3, is less than 90 and in an embodiment which has been constructed, the angle a was made to be roughly 30.

As discussed above, fixed razor blades which are now used to clean tape have a thickness which is at least .004 inch, and accordingly when the cutting edge of the blade is worn away, the width of the surface which is presented to the tape is on the average about .003 inch. Thus, a rotating band whose thickness is .001 inch always has a thickness and hence sharpness which is less than a worn, fixed blade. Further, running the loop over the loop 24 at location X and subsequently over tape 24 at location Y provides a honing action which removes at least in part minor blade damage which occurs at the leading edge at location X.

As the tape is cleaned, the cutting edge of loop 24 is, of course, partially worn away uniformally over its length. However, the effect of twisting the blade to incline it in the fashion shown causes the loop to tend to move upward which compensates for the wear of the blade and tends to keep the cutting edge of the blade at substantially the same location even when its width has been considerably reduced by wear.

In addition, in the particular embodiment of the invention shown in FIGS. 1-6, a worn band or loop of cutting material can be easily and quickly changed by an unskilled operator. Referring particularly to FIG. 4, capstans 28 and 30 are mounted on a housing 34 as are central guide member 36 and side guide members 38 and 40. Slots 42 and 44 are defined between central guide member 36 and side guide member 38 and between central guide member 36 and side guide member 34, respectively, and it is through these slots that the band passes and is inclined in the fashion shown in FIGS. 1, 2 and 3 to provide the honing action discussed above.

Central guide member 36 is fixed in place, but side guide members 34 and 38 have portions 46 and 50' which extend in bores in housing 30 as can be seen in FIG. 5. A spring 52 connects together portions 46 and 50 so that side guide members 38 and 34 are continually urged toward each other to provide a tight fit in slots 42 and 44 at locations X and Y for holding the loop firmly in position and at the desired angle.

Capstan 28 is connected to a conventional motor 60 which can be connected to a source of direct or alternating current as desired. Motor 60 rotates capstan 28 for causing the band to rotate as the tape passes over it, as discussed above. Capstan 30, on the other hand, has a portion 62 which extends into a bore in housing 34. A further member 64 extends into another bore in housing 34 which is substantially transverse to the bore into which portion 62 extends. Capstan 30 is attached to member 64 by extension 62 and moves toward and away from driven capstan 28 with member 64. Spring 66 is also mounted in the bore into which member 64 extends and continuously urges member 64 outward away from driven capstan 28. The outward travel of capstan 30 and member 64 is limited by the band 24 which loops about capstans 28 and 30, as shown in FIG. 1, so that spring 66 keeps loop 24 taut.

To replace a worn loop, member 64 is merely pushed inward manually to cause capstan 30 to move toward capstan 28. At the same time, tapered member 64 contacts portions 50 and 46 of guide members 34 and 38 to cause them to move apart against the urging of spring 52, and thus release the loop from slots 42 and 44. The new loop can then be put in place about capstans 2 8 and 30 and through slots 42 and 44. When the member 64 is manually released, spring 66 causes member 64 to move outward so that guide members 34 and 38 are drawn back together under the influence of spring 52, and the travel of member 64 is halted by the new loop which is about capstan 30 and capstan 28.

Many changes and modifications in the above embodiment of the invention can, of course, be made without departing from the scope of the invention, and, accordingly, that scope is intended to be limited only by the scope of the appended claims.

What is claimed is:

1. A method of cleaning magnetic tape having opposed fiat surfaces comprising the steps of moving said tape in a longitudinal path of travel, and simultaneously contacting at least one flat surface of said moving tape with a moving edge of a closed continuous band of material, said edge being in the form of a cutting edge and said closed band being moved about two spaced points such that said cutting edge moves substantially transversely of said longitudinal path of tape travel and contacts said tape at first and second spaced locations along said longitudinal path to thereby clean said one flat surface of said moving tape.

2. A method as in claim 1 wherein said moving band is inclined in one direction at an acute angle to said path of tape travel at said first location and is inclined in an opposite direction at an acute angle to said path of tape travel at said second location to thereby cause said moving band to tend to move upward to compensate for wear of the cutting edge and keep the cutting edge at substantially the same locations even when its width has been considerably reduced by wear.

References Cited UNITED STATES PATENTS 670,518 3/1901 Schumacher 15-100 UX 1,401,013 12/1921 Teitel 15-100 2,238,996 4/ 1941 Fisher 15-100 2,688,567 9/1954 Franck 134-9 UX 3,193,410 7/1965 Forrest et a1. 134-9 3,370,982 2/1968 Hayunga 15-93 3,475,782 11/1969 Teuber 15-100 X MORRIS 0. WOLK, Primary Examiner J. T. ZATARGA, Assistant Examiner U.S. Cl. X.R. 134-6

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