JP2582219Y2 - Screw fastening device for magnetic tape cassette - Google Patents

Description

[Detailed description of the invention]

[0001]

This invention relates to a pair of synthetic resin magnets.
The present invention relates to a screw tightening device for screwing and fixing an air cassette half , and more particularly to a screw tightening device for preventing deformation such as twisting from remaining in an assembly after screw tightening.

[0002]

2. Description of the Related Art In general, an assembly composed of a pair of synthetic resin molded products, such as a cassette half of a magnetic tape cassette, is integrated by joining a pair of separately molded products with a plurality of screws. Usually, a screw tightening device that automatically performs screw tightening is used for screw tightening.

FIG. 5 is a schematic view of a screw fastening device for fastening the upper and lower cassette halves 20a and 20b of the magnetic tape cassette 20 by screws. First, the magnetic tape cassette 20 in a temporarily assembled state (a state before screwing and fixing), which is arranged at a predetermined position by a positioning mechanism (not shown), is lowered by two half pressers 31 serving as work pressing means lowered from above. Nearly the center of the left and right ends of the cassette half 20b is pressed in a temporarily fixed state. Next, the plurality of screw tightening bits 32 of the lowered screw driving means are respectively inserted into the plurality of screw holes 3 and 3a and simultaneously rotated to screw the screws 14 previously loaded into the screw holes 3 and 3a. Then, when the screw tightening torque reaches a predetermined torque,
The rotation of the screw tightening bit 32 is stopped, and the screw tightening bit 32 and the half retainer 31 are raised to their original positions to complete the screw tightening joint.

[0004]

However, in the synthetic resin molded products such as the upper and lower cassette halves 20a and 20b, deformations such as warpage and twisting are likely to occur after molding depending on the shape and molding conditions of the molded products. In the magnetic tape cassette 20, the posture at the time of screw tightening is determined by the pressing forces of the plurality of screw tightening bits 32 and the two half retainers 31, but the plurality of screw tightening bits 32 correspond to the above. There is a difference in the time to reach each of the screw holes 3 and 3a, and each of the half retainers 31 is independent and has a boss portion having a bonding reference surface at the time of assembly.
a, the magnetic tape cassette 20 is pressed at a position away from the vicinity.

Therefore, it is difficult for the half retainer 31 as described above to securely contact the joining reference surfaces of the upper and lower cassette halves 20a and 20b in the temporarily fixed state, and to press the magnetic tape cassette 20 horizontally. The attitude of the magnetic tape cassette 20 is slightly changed and unstable depending on the order of arrival of the screw tightening bits 32 in the screw holes 3a. Therefore, there is a problem that the assembled product is likely to be twisted and deformed after screw tightening. In particular, in the case of the magnetic tape cassette 20 having a built-in winding hub with a flange, the lower cassette half 20b receives an upward urging force by an internally provided leaf spring, and thus the posture is easily changed in a temporarily fixed state. .

As shown in FIG. 6, when the upper and lower cassette halves 20a and 20b are warped so as to have a gap t between opposing surfaces at the center of the cassette, the lower cassette half 20b of the two of the half presser 31 that presses the substantially central portion of the cassette left and right ends can not correct the warpage of such a cassette half, the deformation intends want is screwed while remaining.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and to correct deformation of a molded article after molding in an assembled article in which a pair of synthetic resin molded articles are joined together by a plurality of screws. It is an object of the present invention to provide a good screw tightening device in which deformation such as twisting does not remain after assembly.

[0008]

SUMMARY OF THE INVENTION The above object of the present invention is one
Pair of synthetic resin upper and lower cassette halves with multiple screws
In order to join and assemble together, the pair of cassette
Work holding means for holding the
With multiple screw tightening bits to tighten and rotate the screws
In the screw tightening device provided with the work holding means,
Are a plurality of through holes through which the screw tightening bits can be inserted.
A flat work holding plate having a through hole;
Multiple compressions to press the cassette half below the plate
A spring and at least a joining level of the cassette half
Of the work holding plate facing around the screw hole near the
A projection provided on the periphery of the through hole;
Due to the action of the pulling, the projecting part of the work holding plate
And hold down the lower cassette half evenly in the joining direction
Screw the cassette half with the screw bit
And the pair of cassette harnesses
Is opposite to the side facing the flat work holding plate.
The surface is supported on a flat support over almost the entire surface
The present invention is achieved by a screwing device for a magnetic tape cassette .

[0009]

According to the configuration of the present invention, the work holding plate securely presses the periphery of the screw hole near the joining reference surface of the cassette half by the projecting portion, so that the joining reference surface of each cassette half is securely contacted. With a pair of cassette
The cassette half can be held in a temporarily fixed state, and each cassette half can be screw-fastened in a stable posture without being affected by the screw fastening bit. Further, since the work holding plate is made of one flat plate, each projecting portion is simultaneously horizontally
Since the cassette half can be pressed, each cassette
Deformation such as warpage or torsion of the tohalf can be corrected and joined together.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. The screw tightening device shown in FIGS. 1 to 4 is for screwing and joining a pair of upper and lower cassette halves 20a and 20b constituting the magnetic tape cassette 20, and a work holding means for holding the magnetic tape cassette 20 in a temporarily fixed state. It comprises a screwdriver main body 4 having a screw driver 12 and a screw driving means 13 and a vertical up-down mechanism 8 for holding the screwdriver main body 4 movably up and down.

The work holding means 12 and the screw driving means 13 are respectively provided on an upper base 5 and a lower base 6 supported by the vertical up-and-down mechanism 8 so as to be able to move up and down.
The upper and lower bases 5 and 6 are connected by a column 7. A plurality of motors M are provided on the upper base 5, and a screw tightening bit 11 is connected to a rotating shaft of each of the motors M to form a screw driving unit 13. These screw tightening bits 11 extend downward through through holes 5a, 6a formed in the upper base 5 and the lower base 6, respectively. A torque sensor (not shown) is attached to each motor M that rotationally drives these screw tightening bits 11.
The rotation of each bit 11 is stopped immediately when the torque of each bit 11 becomes equal to or more than a predetermined torque at the time of screw tightening.

The work holding means 12 has a flat work holding plate 10 supported by the lower base 6 and a suspension rod 9 extending upward from the center of the left and right ends of the work holding plate 10. The upper end of the lower base 6 through hole 6b
, And is projected, and a retaining part 16 is attached to the projected portion. Further, a compression spring 17 inserted into the suspension rod 9 is interposed between the work holding plate 10 and the lower base 6, and the work holding plate 10 is located below the lower base 6. Has been energized. The work holding plate 10 and the lower base 6 have the screw tightening bit 11
Are penetrated so that the through-holes 10a and 6a through which correspond to each other.

At the time of screw tightening, the magnetic tape cassette 20
And opposing wherein the lower surface of the work holding plate 10, the through hole 10 a and the annular member 18 of a thin plate disposed concentrically are mounted, the magnetic tape cassette 20 in the periphery of the through hole 10 a And a protruding portion opposed thereto. In the magnetic tape cassette 20, the joining reference surface for assembling the upper and lower cassette half is provided at the boss portion of the screw hole 3a arranged at each of the four corners of the cassette, and the screw hole 3 is arranged substantially at the center of the cassette. Does not have a joint reference surface, so that the through hole 10 corresponding to the screw hole 3
The annular member 18 is not attached to a. Of course,
It is also possible to attach.

Next, a tightening procedure of the screw tightening device will be described. First, the magnetic tape cassette 20 in a tentatively assembled state in which required mechanical components are assembled is sent to the screwing station by the transfer means, where it is positioned at a predetermined position by a positioning mechanism (not shown). Next, as the screw tightening machine main body 4 held by the vertical up-and-down mechanism 8 moves down, the work holding plate 10 first contacts the lower cassette half 20 b via the annular member 18. Further, when the screwing machine main body 4 is lowered, the work holding plate 10 is compressed by the compression spring 1 as shown in FIG.
7, the upper and lower cassette halves 20a, 20b
When the screw tightening bit 11 is lowered to a predetermined lowering position and engaged with the screw 14, the motor M rotates and the screw tightening bits 11 perform screw tightening.

At this time, the pressing force applied to the work holding plate 10 by the compression spring 17 uniformly acts on each of the annular members 18 by the work holding plate 10 made of a single flat plate. The cassette halves 20a and 20b can be pressed horizontally. Therefore, the upper and lower cassette halves 20a and 20b can be integrally joined by correcting deformation such as warpage or twisting during molding.

Further, the annular member 18 has contact surfaces 20c, 20 which are formed on the screw fastening portions of the upper and lower cassette halves 20a, 20b and serve as joining reference surfaces when assembling the cassette.
d, the upper and lower cassette halves 20 are held in a state where the contact surfaces 20c and 20d are securely contacted.
a, 20b can be held in a temporarily fixed state. Therefore, the attitude of the magnetic tape cassette 20 does not change slightly depending on the order of arrival of the screw tightening bits 11 in the screw holes 3a, and there is no fear that the assembled product after screw tightening will be twisted.

When the screw tightening torque of the screw tightening bit 11 reaches a predetermined value, the rotation of the screw tightening bit 11 by the motor M is stopped, and the screw tightening machine body 4 starts to rise. As the screw tightening machine body 4 rises, the screw tightening bits 11 are separated from the screws 14, but the work holding plate 10 presses the magnetic tape cassette 20 downward by the elastic force of the compression spring 17. Since the work holding plate 10 is left as it is, the work holding plate 10 plays a role of preventing the upper and lower cassette halves 20a and 20b from shifting when the screw is tightened, and also prevents the magnetic tape cassette 20 from rising when the screw tightening bit 11 is raised.

In the above-described embodiment, a thin annular member 18 is mounted as a projection provided on the peripheral edge of the through hole 10a of the work holding plate 10 so as to press the vicinity of the screw hole 3a of the magnetic tape cassette 20. However, the annular member 18 may be an elastic member or a non-elastic member, and the protruding portion may be formed integrally with the work holding plate 10. or,
In the above embodiment, the screw tightening device in the case where the pair of upper and lower cassette halves constituting the magnetic tape cassette are screwed and joined has been described. It can be applied to all screw fastening devices that are joined together and assembled together.

[0019]

As described above, the screw tightening device of the present invention has a flat plate shape having a plurality of screw tightening bits for tightening and rotating each screw and a plurality of through holes through which the screw tightening bits can be inserted. And a protruding portion provided at the periphery of the through hole of the work holding plate facing at least the periphery of the screw hole near the joining reference surface of the pair of synthetic resin magnetic tape cassette halves to be joined. cage, projecting portion of the workpiece holding plate the cassette Ha
The screw tightening bit while pressing the
Screw the cassette half together.

Therefore, the work holding plate is a cassette housing.
The periphery of the screw hole near the reference surface of the cassette is securely pressed by the protruding portion, and the pair of cassette halves can be pressed in a temporarily fixed state with the bonding reference surface of each cassette half securely contacted. Each cassette half can be screwed in a stable posture without being affected by the screw tightening bit. Further, since the work holding plate is made of a single flat plate, each projecting portion can simultaneously press the cassette half horizontally, so that deformation such as warpage or twist of each cassette half is corrected. And can be joined together.

[0021] Thus, in the assembly to be integrated by bonding a pair of cassette half by a plurality of screws, mosquitoes after molding
It is possible to provide a good screw tightening device that corrects the deformation of the set half and does not leave deformation such as twist after assembly.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a screw fastening device according to an embodiment of the present invention.

FIG. 2 is a front view of the screw fastening device according to one embodiment of the present invention.

FIG. 3 is a side view of the screw fastening device shown in FIG. 2;

FIG. 4 is an enlarged view of a main part showing a screw tightening state by the screw tightening device according to the embodiment of the present invention.

FIG. 5 is a schematic perspective view of a conventional screw fastening device.

FIG. 6 is an enlarged view of a main part showing a screw tightening state by a conventional screw tightening device.

[Explanation of symbols]

Reference Signs List 3 screw hole 3a screw hole 4 screw tightener main body 5 upper base 6 lower base 6a through hole 7 support 8 vertical up-down device 9 hanging rod 10 work holding plate 10a through hole 11 screw tightening bit 12 work holding means 13 screw driving means 14 Screw 16 Retaining part 17 Compression spring 18 Ring member 20 Magnetic tape cassette 20a Upper cassette half 20b Lower cassette half

Claims (1)

(57) [Scope of request for utility model registration] 1. A pair of synthetic resin upper and lower cassette halves are joined by a plurality of screws to assemble them integrally.
In a screw tightening device including a work holding means for holding a pair of cassette halves in a temporarily fixed state, and a plurality of screw tightening bits for tightening and rotating each screw, the work holding means can be inserted by each of the screw tightening bits. A flat work holding plate having a plurality of through holes, and the work holding plate is pressed against the cassette half below.
A plurality of compression springs to be pressed, and a projection provided at a peripheral portion of a through hole of the work holding plate facing at least around a screw hole near the joining preparation surface of the cassette half , by the action of the compression spring , The lower cassette half is made uniform in the joining direction with the projecting part of the work holding plate
The cassette hard in the screw tightening bit while pressing the
And the pair of screws
The cassette half has a flat surface
The side opposite to the side to be covered is almost flat on a flat support
Of a magnetic tape cassette characterized by being supported
Screw fastening device .