MXPA96003148A - Cassette de ci - Google Patents

Abstract

The present invention relates to a tape cassette comprising: a cassette housing, a pair of reel cubes around which a magnetic tape is wound, a pair of reel cubes rotatably housed in the cassette housing; guide rollers persones fixed guides to guide the magnetic tape, which is located in a travel path of the tape, between the rotating guide rollers and the fixed guide pins, characterized in that the fixed guide pins are located in the position in which the angle of winding with which the magnetic tape is wound around the fixed guide pins does not exceed 4

Description

CASSETTE DE CINTA BACKGROUND OF THE INVENTION The present invention relates to a tape cassette for recording and reproduction and, particularly, to a unit of fixed guide pins located in the travel path of the tape. Figure 1 of the accompanying drawings shows an example of a conventional tape cassette. A tape cassette, generally represented by the reference number 1 in FIG. 1, is what can be called an audiocassette. The tape cassette 1 includes a cassette housing 2 comprising an upper cassette cassette 2A and a lower cassette cassette 2B, each being made of a styrene resin and secured to each other by an appropriate method such as melting. The cassette housing 2 incorporates therein a pair of spool cubes, that is, a supply spool hub 4 and a capture spool 5 around which a magnetic tape 3 is coiled. Reel cubes 4 and 5 are made of a resin such as POM. The initial portion of the magnetic tape 3 wound around the spool hubs 4, 5 is fixed to the spool hub 5 by a fastener 5a and the terminal portion thereof is fixed to the hub of the supply spool 4 by a fastener 4a . An open portion 6 for exposing the magnetic tape 3 is defined on the front surface of the cassette housing 2, that is, a travel path of the tape is formed in such a way that the magnetic tape 3 unrolled from the supply spool hub it travels in the open portion 6 and is wound around the catch 5 spool bucket. In this travel path of the tape, in the lower case 2B of the cassette, a pair of rotary guide rollers 7, 0 are supported on a symmetrical side and pivot on the left and right sides of the open portion 6. A few bolts fixed column guides 7, 8 are implanted between the rotating guide rollers 7, 8 and the reel cubes 4, 5. Accordingly, the magnetic tape 3 is guided by the rotating guide rollers 8, 8 and the fixed guide pins 9, 10, being transported by them along a predetermined travel path of the belt. As shown in Fig. 2, the fixed guide pins 9, 10 are placed on the outer side of an external tangent common to contacting a practical maximum winding diameter 3A of the magnetic tape 3 wound around the reel cubes 4, 5 and the circumferential surface (guide surface of the tape) of the rotary guide rollers 7, 8. The practical maximum winding diameter 3A is a practical maximum value of the winding diameter of the tape obtained when considering the diameter standards of the cube based on the IEC standard (greater than 21 mm), the thickness of the tape and the length of the tape standardized by the MIAJ standard and a housing space of the cassette and is approximately 53 mm in diameter. Although not shown, between the upper case 2A of the cassette and the reel cubes 4, 5 and between the lower case 2B of the cassette and the reel cubes 4, 5 are placed thin sheets of liner made of a lubricating material such as PET to sandwich the reel cubes 4, 5 in the upper and lower direction. The thin sheets of liner are used in order to allow the magnetic tape 3 to travel in a stable manner and allow the magnetic tape to be wound uniformly around the reel cubes 4, 5. Guiding ribs 11, 12, restrict the tape in width and are located between the reel cubes 4, 5 and the fixed guide pins 9, 10 somewhere in the travel path of the tape. As shown in Figure 3, the guide ribs 11, 12 are formed symmetrically in the upper case 2A of the cassette and in the lower case 2B of cassette of the housing 2. The guide ribs 11, 12 restrict the upper and lower edge portions. of magnetic tape 3, which eliminates the magnetic tape 3 fluctuate in width. Therefore, the magnetic tape 3 can be wound uniformly around the reel cubes 4, 5. Referring again to Figure 1, the open portion 6 at its central portion in which the magnetic tape 3 is exposed is a portion of Head insertion into which a magnetic head (not shown) is inserted. On the inside of the head insertion portion is assembled a leaf spring 15 comprising a shielding metal plate 15 for magnetically shielding the magnetic tape 3 wound around the spool hubs 4, 5 and the magnetic head and a pad of pressure 14 made of felt to push the magnetic tape 3 against the magnetic head. The pressure pad 14 is attached to the central portion of the leaf spring 15. At the front portion of the cassette housing 2, the cassette position reference openings 16, 17 and the winch insert openings 18 are defined symmetrically, 19 in the same positions of the upper case 2A of the cassette and of the lower case 2B of the cassette, respectively. Provided that the tape cassette 1 made in this way is loaded in a cassette player (not shown), positioning pins of the cassette player are coupled to the reference apertures 16, 17 and therefore, the tape cassette 1 is located appropriately. At the same time, the drive arrows of the cassette player hub engage with the reel hubs 4, 5 and the winches (not shown) fit into the winch insert openings 18, 19. In this state, when the user presses the playback button of the cassette player, the magnetic head is then inserted into the open portion 6 and makes contact with the magnetic tape 3. Concurrently with it, the pressing rollers (not shown) are inserted and pushed against the winches through the magnetic tape 3. In this state, the winches rotate by the driving force of a motor (not shown) and the drive arrows of the hub rotate, whereby the take-up spool bucket 5 rotates in counterclockwise direction to transport the magnetic tape 3, which reproduces the magnetic tape 3. When the magnetic tape 3 is transported, resistors are generated against the sliding rga (between the reel hubs 4, 5 and the liner sheets, between the magnetic tape 3 and the liner sheets, between the magnetic tape 3 and the pressure pad 14 and the resistances to the sliding load in the respective parts of the tape cassette 1) and the magnetic tape 3 is stretched to a tension or stiffness backwards by effect of the tension generated in the cassette player. When the magnetic tape 3 is tensioned as described above, a frictional force is generated between the fixed guide pins 9, 10 and the magnetic tape 3. Specifically, as shown in Figure 4, since the fixed guide pins 9, 10 guide the magnetic tape 3 with an angle? of tape winding of a certain degree, and the magnetic tape 3 is stressed, then a frictional force is generated between the fixed guide pins 9, 10 and the magnetic tape 3 in response to the angle? of tape winding. The force generated by the friction generated between the fixed guide pins and the magnetic tape is generally expressed by the following equation (1): Voltage T2 on the side of the capture reel cube = T ^ e- ^ "... (1 ) where T ± is the tension on the supply side, μ is the coefficient of kinetic friction,? is the tape winding angle and T] _- 2 is the friction force.A study of the above equation (1) reveals that the frictional force generated in response to the tape winding angle? changes exponentially.In other words, the frictional force becomes larger according to the winding angle? with which the magnetic tape 3 is wound around the windings. fixed guide pins 9, 10 becomes larger, and the frictional force becomes small according to the angle? of tape winding becomes small. Having examined the conventional tape cassette, is it understood that the winding angle? with which the magnetic tape is wound around the fixed guide pins 9, 10 is large due to the positional relationship of the fixed guide pins 9, 10. The winding angle ü of the magnetic tape 3 fluctuates as the diameter changes with that the magnetic tape 3 is wound around the reel cubes 4, 5 during transport of the magnetic tape 3.

In the conventional tape cassette 1 illustrated, the tape winding angle exceeds a maximum of 40 °.

In all c audio compact assets currently commercially available in conjunction with the illustrated conventional tape cassette 1, the winding angle? with which the magnetic tape 3 is wrapped around the fixed guide pins 9, 10 when the magnetic tape 3 is transported is generally arranged or arranged to exceed a maximum of 40 °. Since the magnetic tape 3 is wound around the fixed guide pins 9, 10 with this large winding angle 0, when the magnetic tape 3 is transported, between the fixed guide pins 9, 10 and the magnetic tape 3 a large amount of noise is generated. Friction force of a magnitude corresponding to this large winding angle? The friction force generated in this way becomes a resistance to the load against the motor for transporting the magnetic tape, thereby increasing the drive current of the motor. The increase in the drive current of the motor leads to the reduction of the life of a battery in a small device such as a portable cassette player, which is disadvantageous in current practice.

SUMMARY OF THE INVENTION In view of the above aspect, an object of the present invention is to provide a tape cassette wherein the friction force generated between the fixed guide pins and the magnetic tape, when the tape is transported, is reduced so that the motor drive current can be reduced. Another object of the present invention is to provide a tape cassette in which the life of the battery in a small cassette player can be extended. A tape cassette is provided which is comprised of a cassette housing, a pair of spool cubes around which the magnetic tape is wound, a pair of spool cubes which are rotatably accommodated in the cassette housing rotating guide rollers and fixed guide pins for guiding the magnetic tape which is located in a travel path of the belt between the rotating guide rollers and the fixed guide pins, wherein the fixed guide pins are located in the position in which the The angle of winding with which the magnetic tape is wound around the fixed guide pins does not exceed 40 °. With the above arrangement, because the angle at which the magnetic tape is wound around the fixed guide pins is reduced compared to the conventional tape cassette, the frictional force generated between the guide pins and the magnetic tape is reduced , which results in that the motor drive current can be reduced, thereby extending the life of the battery.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan view showing a conventional tape cassette with the upper case of the cassette removed; Figure 2 is a fragmentary plan view used to explain the position of the fixed guide pins in the conventional tape cassette; Figure 3 is a fragmentary cross-sectional view used to explain the guide ribs restricting the magnetic tape across; Figure 4 is a schematic diagram showing the manner in which the magnetic tape is wound around the fixed guide pins; Figure 5 is a plan view showing a tape cassette in accordance with the present invention that has been removed from the upper case of the cassette; and Figure 6 is a fragmentary plan view used to explain the position of the fixed guide pins in the cinch cassette in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY The present invention will be described below. Figure 5 shows a tape cassette in accordance with the present invention. A tape cassette, generally represented by the reference number 1 in Figure 5, is called compact audiocassette in a similar way to the conventional tape cassette mentioned above. The tape cassette 1 has a cassette housing 2, and the cassette housing 2 comprises an upper cassette cassette 2A and a lower cassette cassette 2B, each of which is made of styrene resin, and are secured to each other by an appropriate method such as by fusion. The cassette housing 2 incorporates therein a pair of reel cubes around which a tape (magnetic tape) 3 is wound, that is, a supply spool hub 4 and a capture spool cube 5, "of such that the supply spool hub 4 and the catch spool hub 5 can rotate freely.The supply spool hub 4 and the catch spool hub 5 are each made of a resin such as POM. of the magnetic tape 3 is fixed to the capture spool hub 5 by a fastener 5a and the end end of the magnetic tape 3 is fixed to the supply spool hub 4 by a fastener 4a. 2 of the cassette is defined an open portion 6 for exposing the magnetic tape 3. Specifically, a travel path of the tape is formed in such a way that the magnetic tape 3 unwound from the supply spool hub 4 is transported by the open portion 6 and is wound around the catch reel hub 5. In the travel path of the belt, a pair of rotary guide rollers 7, 8 are supported pivotally in the left and right positions of the * open portion 6 of the lower case 2B of the cassette. The fixed column guide pins 9, 19 are implanted between the rotating guide rollers 7, 8 and the spool hubs 4, 5. The magnetic tape 3 is guided by the rotating guide rollers 7, 8 and the fixed guide pins 9, 10 and it is therefore transported along the predetermined travel path of the tape. The position of the fixed guide pins 9, 10 changes considerably, that is to say, the fixed guide pins 9, 10 are located in a position such that the winding angle 0 of the magnetic tape 3 becomes small in comparison with that of the cassette conventional tape The position of the fixed guide pins 9, 10 will be described later in detail.

The guide ribs 11, 12 restricting the magnetic tape 3 across the width are located between the fixed guide pins 9, 10 and the rotary guide rollers 7, 8 somewhere in the travel path of the belt. As shown in Figure 3, the guide ribs 11, 12 are formed in the symmetrical positions of the upper case 2A of the cassette and of the lower case 2B of the housing cassette 2. The extent to which the guide ribs 11, 12 projecting from the inner surfaces of the upper case 2A of the cassette and of the lower case 2B of the cassette is the same. The guide ribs 11, 12 restrict the upper and lower edge portions of the magnetic tape 3, thereby eliminating the fluctuation across the width of the magnetic tape 3 and can be transported substantially in the center of the space within the housing 2. Therefore, the magnetic tape 3 can be wound uniformly around the reel cubes 4, 5. As shown in Figure 5, the open portion 6 in its central part, in which the magnetic tape 3 is exposed, has a head insertion portion in which a magnetic head (not shown) is inserted. On the inside of the head insertion portion, a leaf spring 15 is assembled comprising a shielding metal plate 15 for magnetically shielding the magnetic tape 3 wound around the spool hubs 4, 5 and the magnetic head and a pressure pad 14 made of felt to push the magnetic tape 3 against the magnetic head. The pressure pad 14 is attached to the central portion of the leaf spring 15. In the central portion of the cassette housing 2, the positioning positioning rence openings 16, 17 of the cassette and the winch insert openings are symmetrically defined. 18, 19 in the same positions of the upper case 2A of the cassette and of the lower case 2B of the cassette, respectively. The most specific feature of the tape cassette according to the present invention resides in the positions of the fixed guide pins 9, 10. The positions of the fixed guide pins 9, 10 will now be described in detail. In order to reduce the frictional force generated between the fixed guide pins 9, 10 and the magnetic tape 3 when the magnetic tape 3 is transported, is it effective to reduce the winding angle? with which the magnetic tape 3 is wound around the fixed guide pins 9, 10. As is evident from the aforementioned equation (1), according to the winding angle? with which the magnetic tape 3 is wound around the fixed guide pins 9, 10 becomes small, the frictional force generated between the fixed guide pins 9, 10 and the magnetic tape 3 becomes small. Therefore, to reduce the angle? of tape winding in the tape cassette according to this invention, the fixed guide pins 9, 10 are located in a position difnt from that of the conventional tape cassette. The position of the fixed guide pins 9, 10 is determined as follows. The thickness and length of the magnetic tape 3 wound around the fixed guide pins 9, 10 changes in a variable manner in accordance with the playback (or recording) time. Although the maximum winding diameter is not standardized, a practical maximum value of the ribbon winding diameter obtained when considering the standard value of the cube diameter (greater than 21 mm in diameter) based on the IEC standard, the thickness of the belt and the length of the tape standardized in the MIAJ standard and the housing space of the cassette is approximately 53 mm in diameter. As shown in Fig. 6, based on a maximum ribbon winding diameter 3A of approximately 53 mm, an external tangent common to that which makes contact with the maximum ribbon winding diameter 3A and the circumntial surfaces (guide surfaces) was assumed. of the tape) of the rotating guide rollers 78. Then, the fixed guide pins 9, 10 were located in the position not only of the internal side of the external tangent common to but also in contact with the common external tangent a. Since the fixed guide pins 9, 10 are located in the previous position, in the tape cassette according to the present invention, the winding angle? with which the magnetic tape 3 is wound around the fixed guide pins 9, 10 when the magnetic tape 3 is transported can be smaller than that of the conventional tape cassette. Although the angle of winding? of the magnetic tape 3 fluctuates as the diameter of the tape winding of the reel cubes 4, 5 changes during transport of the magnetic tape 3, in the tape cassette according to this embodiment, can the angle? of tape winding exceeds 40 ° maximum. In this mode, a measured value is a maximum of 39.6 °. Specifically, in the tape cassette according to the present invention, since the angle? of winding with which the magnetic tape 3 is wound around the fixed guide pins 9, 10 is constantly less than 40 °, the frictional force generated between the fixed guide pins 9, 10 can be eliminated when the magnetic tape 3 is transports compared to the conventional tape cassette 3. Accordingly, the friction force is reduced compared to the conventional tape cassette and the load placed on the motor for transporting the magnetic tape 3 is also reduced, so that the motor drive current can be reduced. Having compared the currents consumed in a small cassette player by using the conventional tape cassette and the tape cassette according to the present invention, we compare the results. In accordance with the comparative results, the tape cassette according to the present invention could reduce the current value by approximately 5% compared to the conventional tape cassette. If the fixed guide pins 9, 10 are located closer to the interior of the position that makes contact with the common external tangent to, then the angle of winding? with which the tape 3 is wound around the fixed guide pins 9, 10 can be reduced much more, thereby reducing the frictional force. In this case, when the angle of winding? with which the magnetic tape 3 is wound around the fixed guide pins 9, 10 is large, it is frequently observed that the magnetic tape 3 in the travel path of the tape is not in contact with the fixed guide pins 9, 10. Since the fixed guide pins 9, 10 function so that the magnetic tape does not fluctuate across the width by means of a sliding resistance against the magnetic tape to maintain uniformly the form of winding of the tape. Therefore, if the state in which the magnetic tape 3 is not in contact with the fixed guide pins 9, 10 continues for a long period of time, then the uniform winding pattern of the tape is altered, so that the magnetic tape is pushed strongly against the guide ribs 11, 12, which therefore causes the edge of the magnetic tape 3 to be damaged. If the fixed guide pins 9, 10 are located in the position in which the magnetic tape 3 is not in contact with the fixed guide pins 9, 10 for a long period of time, then the durability of the magnetic tape 3 is deteriorated. Therefore, the fixed guide pins 9, 10 should preferably be located in the proper position as described above. Therefore, as shown in Figure 6, the fixed guide pins 9, 10 should preferably be located on the external side of a common external tangent b which makes contact with the winding diameter (winding diameter obtained when the amounts of Magnetic tape 3 rewound around the reel cubes 4, 5 equalize each other and is approximately 40 mm in diameter) obtained when the magnetic tape 3 wound around the reel cubes 4, 5 is reduced to a maximum of half and the circumferential surfaces (guide surfaces of the tape) of the rotary guide rollers 7, 8. As described above, a tape cassette is provided in which a pair of spool hubs around which a magnetic tape is wound is housed in a rotatable manner in a cassette housing and the rollers Rotating guide and fixed guide pins that guide the magnetic tape are located on a travel path of the tape between a pair of spool buckets. The tape cassette according to the present invention is characterized in that the fixed guide pins are located in the position in which the winding angle of the magnetic tape wound around the fixed guide pins is not greater than 40 °. According to the present invention, since in comparison with the conventional tape cassette, the friction force generated between the fixed guide pins when the magnetic tape is transported is reduced, the motor drive current of a motor carrying can be reduced. to the magnetic tape. As the motor drive current is reduced, the life of the battery in a small cassette player is prolonged and hence, the tape cassette according to the present invention becomes useful. Because the life of the battery is extended, some quantity of spent batteries can be eliminated, which contributes to environmental sanitation. Having described a preferred embodiment of the invention with reference to the accompanying drawings, it will be understood that the invention is not limited to that precise embodiment and that one skilled in the art could make various changes and modifications herein without deviating from the spirit or scope of the invention. the invention as defined in the appended claims.

Claims (5)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property; A tape cassette comprising: a cassette housing; a pair of reel cubes around which a magnetic tape is wound, a pair of spool cubes rotatably housed in the cassette housing; rotary guide rollers and fixed guide pins for guiding the magnetic tape, which is located in a travel path of the tape, between the rotary guide rollers and the fixed guide pins, characterized in that the fixed guide pins are located in the position in the that the angle of winding with which the magnetic tape is wound around the fixed guide pins does not exceed 40 °.
2. 2. A tape cassette according to the claim 1, characterized in that the guide ribs restricting the width of the magnetic tape are located near the fixed guide pins or the rotating guide rollers.
3. A tape cassette according to claim 2, characterized in that the guide ribs are located between the fixed guide pins and the rotating guide rollers.
4. 4. A tape cassette according to the claim 2, characterized in that the cassette housing comprises an upper cassette box and a lower cassette box and in that the guide ribs are located in the upper cassette box and in the lower cassette box. A tape cassette according to claim 4, characterized in that the guide ribs located in the upper cassette box and in the lower cassette box are essentially equal in number to the guide ribs projecting from the inner surfaces of the cassette. top of cassette and lower cassette box.