JPH0433600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a continuous perforation device for perforating thin plastic films and the like used for film/mulch cultivation at regular intervals.

<Prior art> Conventionally, when holes were to be continuously punched at regular intervals in a film as described above, for example, a punching tool provided on a cylinder was rotated together with the cylinder to drill holes at regular intervals on a film that was moving at a constant speed. It was common practice to drill holes.

Fig. 3 is an explanatory diagram of such a process, in which a cylindrical film extruded at a constant speed from an annular nozzle 1 is inflated by air 2 blown from the bottom to become a thin film 3, which is divided into two pieces. It is sandwiched between rollers 4 and becomes a double film. This film is guided by a roller 5 and passes between a cylinder 7 provided with a rotary knife 6 and a brush roller 8, whereby holes are perforated at regular intervals by the rotary knife 6.

In such a case, when changing the interval between consecutive holes (pitch), the entire cylinder 7 provided with the rotary cutter 6 was replaced. Since the film is fed at a constant speed for film formation, it is necessary to maintain the peripheral speed constant even if the diameter of the cylinder 7 changes. For this purpose, it is necessary to change the gear connecting the drive shaft that drives the cylinder 7 and the axis of the cylinder 7 to adjust the rotational speed of the cylinder 7 and keep its peripheral speed constant. Not only is the mechanism required for this complicated, but it is also necessary to have several types of cylinders 7 provided with the rotary blades 6.

<Problems to be Solved by the Invention> The present invention provides various types of cylinders 7 provided with rotary cutters 6.
The purpose of the present invention is to provide a transmission device which does not require a radial speed of the cylinder 7 and which maintains a constant circumferential speed even when the radius of the cylinder 7 is different.

<Means for solving the problem> The cylinder is divided into a plurality of pieces each having a row of rotating blades along the axis, and a mechanism is used in which the radius from the axis to the outer circumference of each divided piece can be adjusted. The outer periphery of the side divided piece is a sprocket or pulley that transmits power by a transmission means such as chain drive or belt drive, so that the driving side rotates at a constant circumferential speed, the driven side also rotates at a constant circumferential speed, and The hole pitch is adjusted by adjusting the radius.

<Operation> By simply adjusting all the divided pieces to the same radius position and replacing the transmission means accordingly, the transmission means is given a constant tension by the adjustment means, so one division You can adjust the drilling pitch to several types with just a cylinder.

<Embodiment> FIG. 1 is an external view of a main part of an embodiment of the present invention, and FIG. 2 is a side view of the same. These figures show the driving device for the cylinder 7 shown in FIG. 3. The drive sprocket 9 rotates at a constant circumferential speed. The driven sprocket is composed of a plurality of split sprockets 11 divided into four in the figure, and teeth of the same pitch as the drive sprocket 9 are carved on the outer periphery. The driven sprockets can each slide in the radial direction on a base plate 12 fixed to the driven shaft 10.
It also has a structure that allows it to be fixed in any position.
A chain 13 is connected between the driving sprocket 9 and the driven sprocket, and this chain 13 is connected to the adjusting sprocket 1 as an adjusting means.
4 gives a constant tension. A set of such driving devices is provided at two locations on the drive shaft 15 and the driven shaft 10, and the divided sprockets 1 of the driven sprockets provided at these two locations are arranged opposite to each other.
1 are connected to each other, for example by a connecting rod 16.
A plurality of rotary blades 6 are provided on this connecting rod 16 in a radially outward direction. This driven sprocket corresponds to the cylinder 7 in Fig. 3, and when changing the hole pitch, all split sprockets 11 are slid on the board 12 and fixed at the desired position, and the chain 13 is replaced. Do this. Correspondingly, the axial position of the brush roller 8 shown in FIG.

Since this embodiment uses a chain for power transmission, it can only be adjusted in increments of one chain link, but stepless adjustment is possible if a belt and pulley are used instead of a chain and sprocket.

<Effects of the Invention> As described above, the apparatus of the present invention can maintain a constant circumferential speed regardless of changes in the outer diameter. When perforating, there is no need to change the forming speed of the plastic film even if the perforation pitch is changed as necessary.

Further, there is no need to prepare a cylinder equipped with a cutting tool for various hole punches and an interlocking gear.

[Brief explanation of drawings]

FIG. 1 is an external view of a main part of an embodiment of the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a process explanatory diagram. 6... Rotating blade, 9... Drive sprocket, 1
1...Divided sprocket, 12... Board, 13...
...Chain, 14...Adjustment sprocket.

Claims (1)

[Scope of Claims] 1. A continuous drilling device for plastic film, comprising: a driving means that rotates at a constant circumferential speed; a driven means that can be divided into a plurality of parts and whose radius to the outer circumference can be adjusted; and the driving means and the driven means. and an adjustment means that applies a constant tension to the transmission means, and the driven means is fixed to a substrate fixed to the driven shaft, and the driven means is slidable in the radial direction on the substrate and can be fixed. A variable pitch continuous drilling device for plastic film, comprising a plurality of divided driven plates and a punching knife fixed to the divided driven plates. 2. In the variable pitch continuous drilling apparatus for plastic film as set forth in claim 1, the drive means is a drive sprocket, the driven means is a driven sprocket, the transmission means is a chain, and the divided driven plate is divided. A variable pitch continuous drilling device for the plastic film, which is a sprocket. 3. In the variable pitch continuous drilling apparatus for plastic film as set forth in claim 1, the driving means is a driving pulley, the driven means is a driven pulley, the transmission means is a belt, and the divided driven plate is divided. The variable pitch continuous drilling device for the plastic film is a pulley.