JPS62204484A - Guide pipe of video tape and its method - Google Patents

Abstract

PURPOSE:To easily mold a device without requiring a precise chamfering, and to improve molding work efficiency, by forming the R of both side peripheral ends of a guide pipe with the clinch of both side end parts. CONSTITUTION:A clamped lengthy pipe 9 is inserted to the through hole 7 of a shearing machine which is arranged at the same circumference from a center point where a rotary body 6, in the center of which the through hole 7 is pierced, is rotated, and also, on which a piece-shaped blade 8 is provided in such a way that it can move on a center line. And by moving the piece-shaped blade 8 in the center point direction of the rotary body 6, making contacting and pressurizing it to the lengthy pipe 9, and simultaneously rotating the rotary body 6, the piece-shaped blade 8 revolves and shears the lengthy pipe 9 press-contacting its outer periphery. Therefore, a sheared part is sheared as if it is teared off, and a sheared peripheral edge part 4 is pressed, then being curved to the inside, and also, since the piece-shaped blade 8 revolves on the outer periphery, all of the peripheral end parts 4 are curved to the inside. And by curving furthermore the curved part 10 of the peripheral end part 4 of a short pipe 9a sheared in a constant length and separated, and clinching it to the inner peripheral plane 3 of the pipe 9a, a guide pipe 1, both side peripheral ends 5, 5 of which are formed to a radius can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a videotape guide pipe incorporated in a videotape cassette and a method for manufacturing the same.

(Prior Art) The guide pipes of the and Deotave have a uniform length of 161 mm, an outer diameter of 6 rings, and an inner diameter of 4.8 mm, and both peripheral ends of the guide pipe must be rounded.

This is because the tape width is determined, and if the side end surfaces are not rounded, it will be difficult to insert the bearing into the interior of the guide pipe during automatic assembly.

Therefore, in the past, a long pipe was cut to a certain length with a saw blade, etc., and the cut end face was chamfered to form a radius, or a long plate material with a width equal to the circumference was cut at a cutting position that matched the pipe length. After continuously punching the ultimate shape notch or 7-shaped notch in the longitudinal direction, cut it, process the separated piece into a cylinder, and further chamfer the peripheral edges on both sides to form a guide pipe. ing.

(Problem to be Solved by the Invention) When the long pipe is used, when cutting it into lengths with a saw blade, etc., the long pipe is scraped off by the thickness of the saw blade, and the length is increased by that amount. This means that the length of the pipe is wasted, and if the number of products manufactured is large, the price of the pipe cannot be ignored.

In addition, if cutting dust from cutting with a saw blade etc. adheres to the pipe, especially if it adheres to the inner surface of the pipe, a special process is required to remove it, which requires time for quality control, and furthermore, it may cause burrs on the cut surface. In addition to the removal of the curve, there are problems such as the necessity to form a radius by chamfering both peripheral edges.

On the other hand, when molding from plate material, positioning notches for separating and cutting appear on the outer periphery of the pipe when molded into a cylinder, and if the notches rub against the tape, it will damage the tape. The bearing is located in a position where it will not rub against the surface.
There are some precautions that must be taken.

The chamfering of the peripheral edges on both sides is essential as described above.

In view of these points, the present invention aims to provide a guide pipe that is simple and easy to produce, has low production costs, and can be installed in a cassette without any obstacles.

(Means for Solving the Problems) The first invention is a videotape guide pipe in which both ends of the pipe are folded back to the inner peripheral surface and both end faces are rounded. Regarding the manufacturing method, a shearing blade is pressed against the circumferential surface of a long pipe while revolving around it to shear it, separating it into short pipes of a certain length, and at the same time bending the sheared circumferential end inward, and further bending the bent circumferential end. It is folded back to the inner peripheral surface of the pipe to form rounded end surfaces on both sides of the pipe.

(Function) Next, the function of the present invention will be explained according to the embodiment shown in the drawings.

FIG. 1 is a longitudinal sectional front view of a videotape guide pipe according to the present invention, in which both ends (2) (2) of the pipe (1), which has a standard length of 16+ms, are attached to the inner circumferential surface (3). It is an overlapping portion having folded portions (4) (4), and both side peripheral ends (5) (5) form a radius due to the folded back portions.

And a pipe (1) with an outer diameter of 6+ua and a wall thickness of 0.3 mm.
If you use , the inner diameter of the overlapping part of the folded both ends (2) (2) will be 4.8 - 1, making it a standard guide pipe, so you can use a pipe with an outer diameter of 61 mm with half the wall thickness of the conventional guide pipe. It is sufficient to use .

Further, since the both side peripheral edges (5) (5) are rounded by folding back, they can be assembled automatically without chamfering.

Figures 2 to 5 show an example of the manufacturing method, and Figure 2 shows a rotating body (6) having a through hole (7) in its center, which is arranged on the same circumference from the rotating center point. It is also a shearing machine equipped with a piece-shaped blade (8) movable on the center line, and a long pipe (9) clamped in a through hole (7) of this shearing machine.
, move the piece-shaped blade (8) toward the center of the rotating body (6), pressurize the long pipe (9), and rotate the rotating body (6) at the same time. Since the shaped blade (8) revolves and shears the outer periphery of the long pipe (9) while pressing against it, the sheared part is sheared so that it can be torn, and the sheared peripheral end (4) is pressed inward. Bent, and piece-shaped blade (
8) revolves around the outer periphery, so the peripheral end (4) is all inward l\
It bends (Figure 3).

Then, the bent part (10) of the circumferential end (4) of the short pipe (9a) that has been sheared to a fixed length and separated is further bent, and the pipe (
By folding back to the inner peripheral surface (3) of 9a) (Fig. 4)
, it is possible to obtain a guide pipe (1) in which both peripheral ends (5) (5) are rounded.

(Effects of the Invention) As described above, the present invention is easy to form because the radius of both side peripheral ends of the guide pipe is formed by folding back the both side ends to the inner peripheral surface, and precise chamfering work is not required as in the conventional method. It is not necessary, and the efficiency of molding work can be improved. Furthermore, since there is no positioning notch that occurs when molding from a plate material, the guide pipe can be mounted on the cassette without any restrictions.

In addition, since the guide pipe of the present invention has both ends overlapped by folding to form a thick wall, the raw material guide pipe can be half as thick as the conventionally used guide pipe, and the cost of raw materials can be reduced. It has a low floor and is economical in that it can be provided at a low cost, and since both ends have an inner diameter that conforms to the standard, there is no problem in inserting and mounting the bearing.

Furthermore, according to the method of the present invention, since the guide pipe is separated and cut by shearing with the cut portion bent inward, there is no need to waste raw materials, and the raw materials can be used effectively, and cutting dust is not generated. Since there is no cutting dust attached to the pipe, the step of wiping it off can be omitted, and the inwardly bent sheared part can be folded back to the inner circumferential surface.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of a videotape guide pipe according to the present invention, FIG. 2 is a side view of the main part showing the state at the time of shearing, and FIGS. 3 and 4 are front views showing the forming process of the guide pipe. , FIG. 5, and FIG. 6 are longitudinal sectional front views of a conventional guide pipe. Code (1) is the pipe (2), both ends (3) is the inner peripheral surface (4) is the folded part (5) is the side peripheral end

Claims (1)

[Scope of Claims] 1. A guide pipe for a videotape, characterized in that both ends of the pipe are folded back toward the inner circumferential surface, and both end faces are rounded. 2. The shearing blade is pressed against the circumferential surface of the long pipe while revolving around it to shear it, separating it into short pipes of a certain length, and at the same time bending the sheared circumferential end inward, and further bending the bent circumferential end to the inner circumferential surface of the pipe. A method for manufacturing a videotape guide pipe, characterized in that the pipe is folded back to form rounded end faces on both sides of the pipe.