US 4,131,243 AGrant
Tape Cassette
Issue Date:1978-12-26
•4 Claims
•3 Drawing Sheets
Abstract
A novel tape cassette which has tape guides that prevent the tape from moving upwardly or downwardly in the cassette and which are constructed by providing interleafed guides which are formed by molding from opposite sides of the top and lower half of the cassette during construction. It has been discovered that the tape guides molded in plastic cassettes tend to incline or tilt away from the front edge of the cassette which result in the tape moving upward or downwardly as it engages such inclined tape guides. The present invention provides for forming a portion of the guides from the upper half of the cassette and other portions of the guides formed from the lower cassette half such that the combination of the upper and lower guides interleaf and result in the tape being maintained in the desired center relationship while traveling in either direction.
Metadata
Assignee
- Sony Corporation
Inventor
- Tetsuo Machida
Application Information
Application Number:US 8213577
Filing Date:1977-08-03
Priority Date:1975-07-23
Art Unit:242
Classifications
IPC:
G03B 104G11B 1532
Field of Search:
242352360197-200;55.19 A72-78 R96;132
Patent Drawings (3 sheets)
Description
Background of the Invention
1. Field of the Invention
This invention relates in general to tape cassettes and in particular to a novel tape cassette.
2. Description of the Prior Art
In prior art tape cassettes the front tape guides which guide the tape by the magnetic heads are generally molded on either the upper or lower cassette half as one unit and are designed to guide the tape passed the front edge portion of the cassette. The cassette is normally made of plastic synthetic resin and it has been found that the guides incline or tilt backwardly after being removed from the mold in which the cassette housings are formed. The guides tend to tilt toward the inside direction of the cassette housing perhaps because the guides thermally shrink after being removed from the mold. For example if the guide is 4 mm in height, the free end of the guide is misaligned by 40 microns inwardly of the housing.
Thus, the prior art machines have utilized guide members extending from one side of the cassette which tilt backwardly into the confines of the cassette and thus result in the tape being transported in a manner which tends to bias it up or down in the cassette or tends to cause it to wave in one direction which is undesirable and will result in the tape being urged toward the bottom or top wall of the cassette housing depending upon the angle of tilt and the side from which the pins extend.
Thus, also when the cassette is turned over for recording or reproducing a signal on the other side of the tape, the tape will also be biased or urged against the same side wall of the cassette which causes the magnetic head to be misaligned with the magnetic track on the tape which causes the reproduction to be of poor quality. This of course presents a large problem for recording or reproducing signals with the proper high quality sound which is desired.
Summary of the Invention
Therefore, the present invention provides molding tape guides partially on the upper cassette half and partially on the lower cassette half with approximately one-half of the guides on the upper cassette half and the other half on the lower cassette half and with the guides spaced so that they interleaf between each other. In a particular embodiment two guides extend from the upper half and two guides extend from the lower half with the guides interleafed between each other such that even if each guide tilts inwardly the tape will pass and be maintained in the center portion of the cassette by the tape guides which causes the magnetic recording and/or reproducing head to engage the tape in the desired position.
Another feature of the invention is that the head pads are supported by a leaf spring which is attached to one half of the cassette by guides which are molded into the cassette. One supporting guide extends from the tape guide on one side and the other supporting guide is mounted symmetrically in the cassette and a center support guide engages the center of the spring and thus the spring is supported between the guides under a spring biasing force.
Another feature of the invention is providing a plurality of projections on the inside walls of the cassette housing so as to prevent the magnetic tape from sticking. The various thin film tapes used with micro-cassettes tend to stick to the walls as the tape becomes slack particularly under humid conditions. Also during molding of the cassette housing a silicon type oil is used for removing the cassettes from the mold which sometimes remains on the wall surfaces and causes the magnetic tape to stick thereto. The projections prevent such sticking.
Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure and in which:
Brief Description of the Drawings
FIG. 1 is a perspective view of a cassette according to the invention;
FIG. 2 is a top plan view of a prior art cassette;
FIG. 3 is a sectional view taken along line III--III in FIG. 2;
FIG. 4 is a sectional view through the cassette;
FIG. 5 is a sectional view through the cassette illustrating certain of the internal parts mounted therein;
FIG. 6 is a sectional view taken along line VI--VI in FIG. 5;
FIG. 7 is a detailed perspective view of the pad supporting spring;
FIG. 8 is an enlarged detailed view taken on section lines VIII--VIII from FIG. 5;
FIG. 9 is a partially cut-away sectional top view through the cassette illustrating the pinch roll and recording heads; and
FIG. 10 illustrates a partial sectional view showing a pinch roller of the side tape.
Description of the Preferred Embodiments
FIGS. 1, 2 and 3 illustrate cassettes of the prior art. The cassette 10 is made of two halves 11 and 12 which are held together by bolts 13, 14 and 16. Feeler openings 17 and 18 are formed near the rear wall of the cassette so as to prevent erasure of the tape if desired. Reels 19 and 22 are rotatably supported in the cassette and have projections 21 and 23 for tape drive and rewind. Openings 24, 26 and 28 extend through both halves of the cassette and corner guide rollers 29 and 31 are mounted adjacent the front edge of the cassette and the tape 32 passes over them and by the vertical guies 33, 34, 36 and 37. Extending upwardly from the lower half 12 of the cassette are guide members 38, 39, 41 and 42 all of which are attached to the lower half 12 and extend upwardly therefrom and are of generally cylindrical shape. A rear spring receiving notch 51 is formed in the rear of the cassette to hold it in the tape machine.
With such prior art tape cassettes, the tape guides 38, 39, 41 and 42 which are attached to only one of the halves 12 of the cassette tend to have their ends away from the base which is attached to the cassette half 12 bent or inclined into the body of the cassette as shown in FIG. 3 in dotted line. Generally, such guides in micro-cassettes are about 4 mm in height and the top of the guides is shifted or displaced upwardly relative to FIG. 3 by about 40 microns. This is caused primarily due to heat shrinking as the cassette halves are removed from the mold in which the cassette halves are formed and during cooling the guide bend as shown in FIG. 3 in dotted line.
FIGS. 4, 5 and 6 illustrate the invention in which the cassette halves 11a and 12a are formed with openings 26, 27, 28 and 24 and support reels 19 and 22 upon which the tape 32 is carried. Behind the protector members 33, 34, 36 and 37 are mounted guide members 52 and 54 which extend upwardly relative to FIG. 6 from the bottom half 12a of the cassette. Additional guide members 57 and 58 extend downwardly relative to FIG. 6 from the cassette half 11a and the guide members 52, 57, 54 and 58 are interleaved between each other as shown in FIG. 6. When the tape rides against the surface of the guides, 52, 57, 54 and 58 it will ride in the center of the cassette between the cassette halves 11a and 12a because the top ends relative to FIG. 6 of guide members 52 and 54 will be bent back into the cassette due to heat shrinking whereas the lower ends relative to FIG. 6 of guides 57 and 58 will be bent into the cassette. The result is that the bending of guides 52 and 54 will be compensated for by the bending of guides 57 and 58 such that the tape 32 will run in the center relative to FIG. 6 of the front opening in the cassette such that magnetic heads will maintain alignment with the tape and, thus, improved reproduction will occur.
Also, when the tape is turned over for recording or reproducing a signal on its other side the tape will be biased toward the center of the cassette and proper alignment will exist thus allowing the recording and reproduction of signals with high fidelity.
Thus, in accordance with the present invention the tape guides 57 and 58 are molded and extend downwardly from the upper cassette 11a whereas the tape guides 12 and 54 extend upwardly and are molded from the lower cassette half 12a as shown in FIGS. 4, 5 and 6.
Even though each of the guides tilts inwardly, the tape will pass at the center of the cassette and exact alignment with magnetic recording and/or reproducing heads will be obtained.
Wiper pads 42 and 43 are mounted on a leaf spring 61 as illustrated in perspective view in FIG. 7 and have end tabs 64 and 66 at its opposite ends which engage spring guies 53 and 56. A center spring engaging member 62 is formed in the cassette and the spring is held between the guides 53, 56 and member 62 as shown in FIG. 5, for example. As the tape 32 passes the wiper pads 42 and 43, it will be wiped and cleaned by the pads 42 and 43. The guide 53 is attached to and extends from the guide 52 and guide 56 is symmetrically spaced relative to guide 53. The spring 61 is maintained between the spring support 62, 53 and 56 due to spring tension in the spring.
On the side walls 91a and 91d of the lower half of the cassette 12a as well as the side walls 91b and 91c of the upper half 11a of the cassette are formed a number of projections 98a, 98d, 98b and 98c. As shown in greater detail in FIG. 8, the projections 98 may comprise a number of individual projections 92, 93, 94 and 96 which extend from the side wall 91 adjacent the bottom wall 97 of the cassette. The projections 98 engage the tape 32 and prevent it from sticking to the side walls of the cassette. The very thin film tape used with Micro cassettes tends to stick to the walls when the tape is slack in the cassette housing due to high humidity conditions. Also, silicon oil is used for removing the molded cassette housing from the mold during manufacture and such oil remains on the wall surfaces and causes the magnetic tape to stick thereon. The projections 98 hold the tape away from the wall and prevents such sticking. Although the projections 92 through 93 are illustrated as triangular in cross-section in FIG. 8 it is to be realized, of course, that they may be rounded or of any suitable shape so as to hold the tape away from the side walls 91 of the cassette.
It is seen that this invention provides for a proper alignment in tape cassettes by forming tape guides from opposite halves of the cassette such that they interleaf between each other which provides accurate guiding of the tape. The invention also encompasses a novel leaf spring and support for head pads and projections on the side walls of the cassette for preventing sticking.
FIG. 9 is a sectional view illustrating the cassette of the invention in use with a center pinch roll 81 and center capstan 82 which extends through the opening 27. Magnetic heads 83 and 84 are mounted so as to engage the tape 32.
FIG. 10 illustrates a side drive with a pinch roll 86 which engages a capstan 87 that passes through opening 26 in the cassette and magnetic heads 88 and 89 are mounted so as to engage the tape 32.
Although the invention has been described with respect to preferred embodiments it is not to be so limited as changes and modifications may be made which are within the full intended scope as defined by the appended claims.
Claims
I claim as my invention:
1. A tape micro-cassette formed of molded plastic and having a pair of mating lower and upper cassette members and a pair of sidewalls at opposite ends thereof, and including a pair of tape reels rotatably mounted in said cassette with thin film magnetic tape extending between said reels and said tape wound on said reels such that it is payed out from one reel and taken up by the other reel on the sides of said reels adjacent said pair of sidewalls and said tape travels substantially parallel and in close proximity to said pair of sidewalls and said cassette having a portion available for recording and playback functions along a front wall of said cassette which has an open area, a pair of guide rollers for said tape mounted in the corners of said cassette between said front wall and said pair of sidewalls, respectively, a plurality of tape guides extending generally parallel to said front face of said cassette and providing guides for said tape at said front face and said inner walls of said pairs of sidewalls, said sidewalls being formed with roughened areas so that as the tape is payed out from one reel and taken up by the other reel it contacts the roughened areas of said inner pair of sidewalls, which prevents said thin film tape from adhering to said pair of sidewalls.
2. A tape micro-cassette according to claim 1 wherein said roughened areas are formed of a plurality of projections which extend from said sidewalls toward each other and prevent the thin film tape from touching any portions of said sidewalls except said projections as it moves substantially parallel to said sidewalls.
3. A tape micro-cassette according to claim 2 including a pair of guide pins each mounted adjacent one of said thin film pairs of sidewalls so as to engage said tape and cause it to pass closely adjacent said pair of sidewalls and substantially parallel to said pair of sidewalls.
4. A tape micro-cassette according to claim 1 including three holding members mounted in said cassette adjacent said front face, a flexible wiper and support member attached to said three holding members and a flexible wiper pad attached to said flexible wiper pad support member adjacent said front face such that said wiper pad engages said thin film tape.