JPH0227433Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape cassette such as a compact cassette.

When a magnetic tape cassette (hereinafter simply referred to as a cassette), such as a compact cassette or a microcassette, is inserted into a recording/playback device and is in recording or playback mode, the magnetic tape is pressed against the magnetic head and is pressed onto both sides of the head. It comes to slide on a pin (hereinafter referred to as a head pin) that protrudes from one cassette half to the other cassette half. Therefore, the running attitude of the magnetic tape with respect to the magnetic head is greatly influenced by the attitude of these head pins, so these head pins are connected to the cassette half (more precisely, to the recording/playback equipment of the cassette half) to prevent azimuth loss. (with respect to the mounting surface).

For the reasons mentioned above, when manufacturing a mold for a cassette half or manufacturing a half, great care is taken to ensure the perpendicularity of the head pin. However, in the half manufacturing process where molten plastic is injection molded and then cooled and solidified, if the manufacturing speed is increased with emphasis on productivity, the molded cassette half will warp due to heat shrinkage strain during cooling and solidification. I often put it away. If the cassette half warps, the verticality of the head pin will naturally become inaccurate.

To explain in more detail, the magnetic tape cassette described above generally has a cassette half 2 having a half window, a screw hole provided at a corner, and a center screw hole provided closer to the half window than the head pin installation section. After accommodating the magnetic tape therein, the two are formed by tightening and connecting screws passed through the screw holes and the center screw hole.

Therefore, if the cassette halves are not warped, tightening the screws passed through the corner screw holes and the center screw hole (generally these are tightened at the same time) will tightly tighten the opposing peripheral walls of both cassette halves. come into contact with each other.

Further, the above-mentioned warping generally occurs in a direction in which the outer surface of the half is concave, that is, in a direction in which the opposing peripheral wall portions of both cassette halves are separated. Therefore, even if the cassette half is slightly warped locally near the corner, such warpage can be corrected by tightening the screw inserted through the screw hole in the corner. However, since the head pin is installed at a position away from the corner of the cassette half, that is, near the center in the left-right direction, the warpage of the installation part of the head pin cannot usually be completely prevented even if the screws at the corners are tightened. It cannot be corrected.

On the other hand, as mentioned above, there is a center screw hole near the head pin installation portion, and by tightening the screw passed through the center screw hole, the warpage around the center screw hole may be corrected. However, while the direction of this warp is as described above, the center screw hole is located closer to the center of the cassette half than the head pin installation area, so the screw inserted through it is fully inserted (in other words, the center screw hole of both cassette halves is Even if the head pins are tightened (until the peripheral end surfaces of the head pins come into contact with each other), it is difficult to completely correct the warpage of the head pin mounting portion on the outer side, that is, on the side of the peripheral wall.

The present invention was developed in view of the above circumstances, and provides a cassette in which even if the cassette half warps during injection molding, it can be corrected during subsequent cassette assembly, and the aforementioned head pins can be set accurately vertically. The purpose is to provide

The cassette of the present invention was obtained by focusing on the fact that the warpage of the cassette half during half production is generally such that the outside of the half is concave, as described above. After storing the magnetic tape inside, insert two cassette halves each having a screw hole provided in the upper part and a center screw hole provided closer to the half window than the head pin installation part, and then insert the magnetic tape through the screw holes and the center screw hole. In a magnetic tape cassette formed by tightening and connecting screws, a contact portion protruding toward the other cassette half is provided near the center screw hole of at least one of the cassette halves and at a position on the half window side, and the corresponding contact portion When both cassette halves are assembled before tightening the center screw, the two cassette halves come into contact with the other cassette half, and at least a part of the end surface around the center screw hole on the side where the head pin is installed is attached to the other cassette half. The length is such that it can be separated from the tip surface around the center screw hole.

When the above-mentioned abutting part is provided, by tightening the center screw after assembling the halves, the parts of the cassette halves outside the relevant abutting part, that is, the part where the head pin is provided, will move toward each other using this abutting part as a fulcrum. They begin to bend as if approaching each other. The bending of the cassette half caused by tightening this screw is opposite to the warping of the cassette half as described above, so by tightening the center screw in this manner, the warping of the cassette half is corrected. Of course, the amount of correction for the warp of the cassette half increases as the center screw is tightened, so it is possible to accurately set the verticality of the head pin by adjusting the amount of tightening of the center screw.

In general, cassette halves molded from a common mold have the same tendency to warp, so for cassette halves molded from a certain mold, find out how much center screw tightening is required to make the head pin vertical. For the cassette halves molded from this mold, this center screw tightening amount may be applied uniformly.

The mechanism for improving the verticality of the head pin has been explained above, but in the case of compact cassettes, etc., the cross section where the capstan and pinch roller are inserted at a position closer to the guide roller than the head pin during recording and playback is omitted. The magnetic tape slides on the M-shaped ribs. Of course, it is important to set these ribs vertically, but the direction of inclination of these ribs when the cassette half is warped is the same as the direction of inclination of the head pin. The verticality of these ribs can also be adjusted to some extent by tightening.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the inner surface shape of a cassette half of a compact cassette according to one embodiment of the present invention, and FIG. 2 is a side sectional view of this compact cassette. As shown in Figure 1, cassette half 1
These include the half window 2, the screw holes 3a, 3b, 3c, 3d and 3e provided at the four corners and near the center of the cassette opening, the rib 4, and the two head pins 5a, 5.
(b) It has pins 6a, 6b, etc. provided above and below the half window 2 in the figure, and is basically formed in the same manner as the cassette half of a conventional compact cassette.

The cassette half 1 incorporates a magnetic tape wound around a rib, a friction sheet, a guide roller, etc. (all not shown). Thereafter, the mating cassette half 10 is assembled, and the five screws inserted into the screw holes of the mating cassette half 10 are inserted into the screw holes 3a, 3b, 3c, 3d, and 3e.
The two cassette halves 1 and 10 are then tightened together (see FIG. 2).

The above-mentioned cassette halves 1 and 10 are formed by injection molding plastic, but when the manufacturing speed is increased, the outside tends to warp in a concave manner as shown in FIG. In the case of a compact cassette, the recording/reproducing device mounting surfaces 1a, 10a of the cassette halves 1, 10 are flat, and as described above, the head pins 5a, 5b, The tape sliding surface 4a of the rib 4 must be vertical, but if the cassette halves 1, 10 warp as described above, these conditions will of course not be met. Therefore, in the compact cassette of the present invention, the length of the pin 6b that is closer to the center screw hole 3e among the two pins 6a and 6b mentioned above is specially set, so that the warpage of the cassette halves 1 and 10 is prevented when the cassette halves are assembled. has been corrected, and the verticality of the head pins 5a, 5b, etc. has also been improved. The mechanism will be explained in detail below.

As shown in FIG. 2, the pin 6b of the cassette half 1 and the corresponding pin 16 of the cassette half 10 are attached to the tip surfaces of the peripheral parts 7, 17 of the center screw holes 3e, 13 of the cassette halves 1, 10. ,
In other words, the surfaces in which the screw holes are drilled are brought into contact with each other before coming into contact with each other, so that the peripheral parts 7 and 17 of the center screw holes are not brought into contact with each other. When the center screw 8 is tightened in this state, both the cassette halves 1 and 10 are attached to the pins 6b and 16.
The two can be bent toward each other using the abutment part as a fulcrum. Therefore, cassette half 1,
10 is corrected and the surfaces 1a and 10a become flat, and the sliding surfaces 4 of the head pins 5a and 5b and the ribs 4
The verticality of the sliding surface of a or a similar rib (not shown) provided on the cassette half 10 side is also improved.

The amount of correction for the warpage of these cassette halves 1 and 10 naturally increases or decreases depending on the tightening amount of the center screw 8, so by setting the tightening amount of the center screw 8 to an appropriate amount, the head pin 5
The verticality of a, 5b, etc. can be set accurately.

Note that the center screw 8 and the other four screws are normally tightened at the same time in order to improve work efficiency and eliminate local distortion of the cassette half.

In the embodiment described above, pins 6b, 16
The peripheral parts 7 and 1 of the center screw holes 3e and 13 are
7 is made to float, but the abutting portions that prevent the abutment of the periphery of the center screw hole in this way are not limited to the pins 6b and 16 in the positions described above, but these abutting portions. In short, it suffices if it is provided near the center screw hole and at a position closer to the half window than the center screw hole. For example, as shown in FIG. 3, the peripheral part 7a of the peripheral part 7 of the center screw hole 3e, which is closer to the half window side (right side in the figure), comes into contact with the peripheral part 17 of the center screw hole of the mating cassette half 10. A protrusion 20 may be provided. Even in this case, most of the end surface of the center screw hole surrounding area 7 on the head pin installation side is
Since it separates from the center screw hole surrounding area 17 of the mating cassette half 10, as the center screw 8 is tightened, the center screw hole surrounding area 7, 17 deforms slightly, and the cassette half 1, 10
The warpage is corrected. Further, the shape and number of the contact portions are not limited to those in the above embodiments, and, for example, a quadrangular prism-shaped contact portion or a plurality of contact portions may be formed.

As explained in detail above, the magnetic tape cassette of the present invention corrects the warpage of the half when assembling the cassette even if a warped cassette half is used.
The sliding part of the magnetic tape can be precisely set vertically, so when manufacturing the cassette of the present invention, it is possible to increase the manufacturing speed of the cassette half, and productivity is significantly improved. be done.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a cassette half used in the present invention, FIG. 2 is a side sectional view showing an embodiment of the present invention formed using the cassette half shown in FIG. 1, and FIG. FIG. 3 is a side sectional view showing another embodiment of the present invention. 1, 10...cassette half, 2...half window, 3a, 3b, 3c, 3d...screw hole, 3e,
13... Center screw hole, 6b, 16... Pin,
7, 17... Center screw hole periphery, 8... Center screw, 20... Contact protrusion.

Claims (1)

[Scope of claim for utility model registration] Half window 2, screw hole 3a provided in the corner,
3b, 3c, 3d, and center screw holes 3e, 13 provided closer to the half window 2 than the installation portions of the head pins 5a, 5b.
After accommodating magnetic tape inside 1 and 10,
In the magnetic tape cassette which is connected by tightening the screws 8 passed through the screw holes 3a, 3b, 3c, 3d and the center screw holes 3e, 13, there is a half window near the center screw hole 3e of at least one cassette half 1. A contact portion 6 protruding toward the other cassette half 10 is located on the second side.
b, 20 are provided, and the corresponding contact portions 6b, 20 are connected to both cassette halves 1,
10 come into contact with the mating cassette half 10 in the assembled state before tightening the center screw, and at least a part of the end surface of the peripheral part 7 of the center screw hole 3e on the head pin installation part side is attached to the mating cassette half 10. 1. A magnetic tape cassette characterized in that the magnetic tape cassette has a length that can be separated from the end surface of the peripheral portion 17 of the center screw hole.