JPH0536671U - Magnetic tape cassette - Google Patents

Abstract

(57) [Summary] [Purpose] Reduction of mold processing time for upper and lower cassette halves,
Together with the stability of positioning when welding each cassette half,
Provided is a magnetic tape cassette having improved weldability of upper and lower halves. A magnetic tape cassette having a pair of tape winding bodies in which a magnetic tape is rotatably wound in a case body formed of an assembly in which a pair of upper and lower cassette halves are welded. The upper and lower cassette halves 2a and 2b are provided with a welding rib 10 protruding on one side and a welding receiving groove 14 facing the welding rib 10 on the other side, and both side slopes 11 and 12 of the welding rib 10 are formed. Is larger than the angle θ formed by the slopes 15 and 16 on both sides of the welding receiving groove. Further, when the upper and lower cassette halves are stacked, the corner portions 17 and 18 of the opening edge of the welding groove formed by the inclined surfaces 15 and 16 of the welding receiving groove come into contact with the inclined surfaces 11 and 12 of the welding rib. Magnetic tape cassette configured in.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic tape cassette in which a case body is composed of an assembly of upper and lower cassette halves used in an audio tape recorder, and more particularly, a front opening having a front opening into which a magnetic head or the like can enter in the center of the front surface of the cassette. The present invention relates to a magnetic tape cassette having a structure in which cassette halves are welded.

[0002]

[Prior Art]

 Conventionally, a magnetic tape cassette incorporating a pair of tape winding bodies is generally used for audio and the like. The basic structure of this audio magnetic tape cassette is shown in FIG. Note that FIG. 4 is a perspective view showing a combined state of the upper and lower cassette halves. As is well known, the magnetic tape cassette 1 shown in FIG. 4 has a pair of upper and lower cassette halves 2a and 2b integrally fixed by screws 3 and a pair of hubs 4 on which a magnetic tape T is wound. The structure is rotatably supported by the insertion holes 4a and 4b.

Although the cassette halves 2a and 2b have some protrusions, ribs, and partition walls inside the flat plate-shaped top plate portion 5, basically, the top plate portion 5 and the top plate portion 5 The side plate portion 6 formed at the edge of the portion 5 has a substantially U-shaped cross section. In addition, the top plate portion 5 is formed with a trapezoidal portion 7 having an opening portion at the front portion of the cassette and having a trapezoidal planar shape. In particular, in recent years, magnetic tapes have been improved in quality for recording and reproduction with higher performance, and along with this, there has been an increasing demand for higher quality case bodies.

However, in the structure in which the upper and lower cassette halves 2a and 2b are fastened with screws 3, a gap is formed on the mating surfaces of the upper and lower cassette halves due to deformation of the cassette halves 2a and 2b and loosening of the screws 3. In some cases, dust easily enters the magnetic tape cassette and adheres to the built-in magnetic tape T to deteriorate recording / reproducing characteristics. Normally, the cassette halves 2a and 2b are trapezoidal portions 7. In addition, the cassette halves 2a and 2b are firmly fixed by the tightening force of the five screws 3 at the four corners.

On the other hand, in recent years, the low price of the magnetic tape cassette has become a major factor in its commercial value. In such a situation, for example, fixing the upper and lower cassette halves 2a and 2b with screws requires parts such as screws and man-hours, and it is difficult to say that productivity is good. Ultrasonic welding of the end surface of the side plate portion 6 has been performed.

A magnetic tape cassette of the type in which the upper and lower cassette halves are welded and a molding die thereof will be described with reference to FIGS. 5 and 6. The magnetic tape cassette 1 shown in the cross section of FIG. 6 (a schematic cross section of a portion corresponding to the cross section AA of the cassette case shown in FIG. 4) has the same structure as the above-mentioned screw-fastened tape and the upper cassette half 2a. The lower cassette half 2b is welded to the end faces of the both side plate portions 6 by welding. It should be noted that the illustration of parts inside the case body is omitted for convenience. In the conventional type, the joining surfaces c of the pair of upper and lower cassette halves are, for example, the side plate portions of the above cassette halves 2a as shown in FIG. A protruding welding rib 10 is integrally formed on the end surface of the welding portion 6, while the end surface of the side plate portion 6 of the lower cassette half 2b is formed into a flat surface or an appropriate dent so that the molten portion of the welding rib 10 does not protrude. It was common to be done.

[0007]

[Problems to be solved by the device]

 That is, the welding rib 10 projecting in a triangular cross-section is integrally formed on the joining surface of the upper cassette half 2a by injection molding. The ultrasonic energy is smaller as the tip is thinner during ultrasonic welding. This is because it concentrates on the part and the welding is quick and easy. However, in the mold M used for injection molding in this way, the recessed portion e forming the welding rib 10 is usually produced by electric discharge machining, but at the time of completion of the recessed portion e by this electric discharge machining, In addition to forming a matte surface rough surface on the slopes d, d on both sides thereof, the lower tip t of each slope does not form an acute angle but has a rounded shape.

As a result, the tip 10a of the welding rib 10 formed by such a die becomes an obtuse angle, and the energy loss during welding and the welding time both become large, so that the die is eventually removing roundness of the lower tip t of M (in the lower side front end t _a shown by imaginary line in the drawing is an acute angle as shown the distal end 10a in phantom) are forced to use the engraving machine, For this reason, processing time is required, and if the tip of the welding rib 10 is rounded, there is a problem in that the positioning of the upper and lower cassette halves is unsafe during welding. The present invention is intended to solve the above-mentioned inconveniences, and shortens the die processing time, stabilizes the positioning accuracy when welding the upper and lower cassette halves, and shortens the welding time and ensures the welding. The purpose of the present invention is to provide a magnetic tape cassette capable of increasing the cost at a low cost.

[0009]

[Means for Solving the Problems]

 The above object of the present invention is to provide a magnetic tape cassette in which a pair of tape winding bodies in which a magnetic tape is rotatably wound is housed in a case body formed by welding a pair of upper and lower cassette halves together. A welding rib protruding to either one of the joining surfaces of the half is formed, and a welding receiving groove facing the welding rib is formed on the other side of the joining surface. The angle Θ formed by the slopes on both sides of the welding rib is the welding receiving groove. Is larger than the angle θ formed by the slopes on both sides of the welding groove, and when the upper and lower cassette halves are joined, the corner of the opening edge of the receiving groove formed by the slope of the welding receiving groove is the welding rib. It is achieved by a magnetic tape cassette characterized in that it is configured to contact the slope of the.

[0010]

Embodiment

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1, 2 and 3 show an embodiment of the present invention, and FIGS. 1 and 2 are, for the sake of convenience, shown in the upper and lower cassette halves at a portion corresponding to line xx of FIG. The principal part enlarged sectional view which shows the process of joining is shown. FIG. 3 is a plan view of the magnetic tape cassette. In the magnetic tape cassette 1 shown in FIG. 3, a pair of upper and lower cassette halves 2a (the lower cassette half 2b is not shown) has an end face of the side plate portion 6 (shown by diagonal lines in FIG. 3) as in the conventional welding type. It is welded in the area B). Inside the magnetic tape cassette 1, a pair of hubs 4 around which a magnetic tape T is wound are rotatably supported by reel shaft insertion holes 4a and 4b as in the conventional case. As a matter of course, the cassette half 2a has a plurality of projections, partition walls, side plate portions 6 and the like inside the flat plate-shaped top plate portion 5 as in the conventional case, and the overall shape is a substantially U-shaped cross section.

The structural features of this embodiment will be described with reference to FIGS. 1 and 2. 1 and 2 are views for explaining the welding process of the upper and lower cassette halves as described above, and FIG. 1 shows the welding ribs 10 formed on the joint surface of the upper cassette half 2a and the lower cassette half. FIG. 2 shows a state before being overlapped with the welding receiving groove 14 formed on the joining surface of the half 2a, and FIG. 2 shows a state in which the both portions are in contact with each other. In FIG. 1, the welding ribs 10 formed on the end surface of the side plate portion 6 of the upper cassette half 2a have slopes 11 and 12 on both sides of the welding rib 10 which are formed in the end surface of the lower cassette half 2b as described later. It is defined to make line contact (point contact in the figure) with the corners 17 and 18 of the opening edge of the welding receiving groove 14. The tip 10a of the welding rib 10 is not rounded at an acute angle but is appropriately rounded. On the other hand, the lower cassette half 2b is formed with the welding receiving groove 14 having a size capable of receiving at least the tip 10a of the welding rib 10.

In the present embodiment, a particularly important structure is that the angle θ formed by the slopes 11 and 12 of the welding rib 10 and the angle θ formed by the slopes 15 and 16 of the welding receiving groove 14 are large. There is a difference. That is, the angle Θ formed by the slope of the welding rib 2 is larger than the angle θ formed by the slope of the welding receiving groove 14, and the opening of the welding receiving groove 14 is further formed. The width L of the welding rib 10 is configured so that the corners 17 and 18 contact the slopes 11 and 12 of the welding rib 10.

With the above-described configuration according to the present embodiment, when the upper and lower cassette halves 2a and 2b are superposed, as shown in FIG. 2, a corner portion of the welding receiving groove 14 of the lower cassette half 2b is formed. 17 and 18 and the slopes 11 and 12 contact each other. Therefore, since the abutment makes line contact with the vicinity of the tip of the welding rib 10 at an acute angle, unlike the conventional type in which only the tip of the welding rib makes contact, two line contact is made on both slopes. As a result, since the ultrasonic energy is consumed very effectively, the welding operation can be performed very quickly, and in addition, the tip 10a of the welding rib 10 is located at the opening of the welding receiving groove 14. Since it is in a depressed state, a very stable contact can be maintained when the upper and lower cassette halves are joined, the welding operation itself can be stabilized, and the positioning of the respective halves during joining is also automatically determined.

Further, when the upper and lower cassette half contact structures are adopted as in the present embodiment, there is no problem even if the mold M such as the conventional type shown in FIG. There is no need to further machine grooves by electric discharge machining with an engraving machine, which reduces wasteful man-hours and reduces the cost of products. In addition, since the joint surface has irregularities, the joint area can be increased and the mechanical strength of the joint (welded portion) can be increased. In the above embodiment, the upper cassette half 2a of the upper and lower cassette halves is formed with the welding rib, and the lower cassette half 2b is formed with the welding receiving groove. However, in the present invention, it goes without saying that Even if the formation positions of the welding receiving groove 14 and the welding rib 10 are reversed from those in FIG. Further, the size of the angle Θ of the welding rib and the angle θ of the welding receiving groove 14 can be appropriately selected only by setting the magnitude relationship as described above.

[0015]

[Effect of the device]

 As described above, in the magnetic tape cassette of the present invention, the upper and lower cassette halves are joined to each other by the welding ribs projecting to one side and the welding receiving groove facing the welding ribs on the other side. The angle Θ formed by the slopes on both sides of the welding rib is larger than the angle θ formed by the slopes on both sides of the welding receiving groove, and is formed by the slopes of the welding receiving groove when the upper and lower cassette halves are joined together. The corner portion of the opening edge of the receiving groove is configured to contact the slope of the welding rib. Therefore, even if the tips of the welding ribs do not have an acute angle as in the conventional case, when the upper and lower cassette halves are overlapped with each other, it is possible to make line contact with both corners of the welding receiving groove and the vicinity of the tips of the welding ribs at an acute angle. Therefore, ultrasonic energy is consumed very effectively without forming the tip of the welding rib at an acute angle as in the conventional type, and therefore the welding operation can be performed very quickly. Further, since the tip of the welding rib falls into the opening of the welding receiving groove, a very stable contact can be maintained during the joining of the upper and lower cassette halves, and the welding operation itself can be stabilized. Positioning when joining the halves can also be determined automatically. Furthermore, by adopting the contact structure of the upper and lower cassette halves according to the present invention, it is not necessary to further process the groove by electric discharge machining with an engraving machine as in the conventional case in order to make the tip of the welding rib an acute angle. It is possible to save unnecessary man-hours and promote low cost of products.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of essential parts showing a state before the upper and lower cassette halves are stacked on each other according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of an essential part showing a state in which upper and lower cassette halves are overlapped with each other according to an embodiment of the present invention.

FIG. 3 is a plan view of the magnetic tape cassette of the present invention.

FIG. 4 is a perspective view of a conventional magnetic tape cassette.

FIG. 5 is an enlarged cross-sectional view of a main part showing a side plate part of a conventional half case of a magnetic tape cassette and a mold for molding the side plate part.

6 is an enlarged cross-sectional view schematically showing a joined state of upper and lower cassette halves in a portion corresponding to the AA cross-sectional portion in FIG.

[Explanation of symbols]

 1 Magnetic Tape Cassette 2a Upper Cassette Half 2b Lower Cassette Half 4 Hub 5 Top Plate 6 Side Plate 10 Welding Rib 10a Tip 11 and 12 Slope of Welding Rib 14 Welding Groove 15 and 16 Slope of Welding Groove 17 and 18 Corner Θ Angle formed by slope of welding rib θ Angle formed by slope of welding groove M Mold T Magnetic tape

Claims (1)

[Scope of utility model registration request] 1. A magnetic tape cassette having a pair of tape winding bodies, wherein a pair of upper and lower cassette halves are welded together, and a pair of tape winding bodies, on which a magnetic tape is rotatably wound, is incorporated in a case body. The surface is formed with a welding rib projecting in one side and the other side is formed with a welding receiving groove facing the welding rib, and an angle Θ formed by both side inclined surfaces of the welding rib is on both side inclined surfaces of the welding receiving groove. When the upper and lower cassette halves are overlapped with each other, the angle of the opening edge of the receiving groove formed by the inclined surface of the welding receiving groove contacts the inclined surface of the welding rib. A magnetic tape cassette characterized by being configured as follows.