JPH0136832Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a device for adjusting the tension of a sheet such as paper pulled out from a paper roll.

[Conventional technology]

The heat-fusible packaging paper wound on a roll is rewound, folded in half in the length direction, and inserted between a pair of heating rolls. The operation involves supplying a certain amount of medicine between the folds, and after feeding the medicine, the packaging paper is sent forward a certain length, and the heating roller heats and seals the width direction and both sides of the packaging paper, making it airtight. In a drug packaging machine that alternately repeats the operation of forming a bag part, when the roll of packaging paper rotates by inertia during the unwinding operation of the packaging paper,
Since the packaging paper becomes slack between the roll support and the heating roll, causing trouble, a load is normally applied to the roll body in the direction of rotation to apply tension to the packaging paper.

In Japanese Utility Model Publication No. 54-549, a support cylinder is rotatably fitted on the outside of the shaft, and a friction plate and a spring are fitted on the outside of the shaft inside the support cylinder, and the elasticity of the spring A paper tube is disclosed in which a friction plate is pressed against a circumferential ridge formed on the inner circumferential surface of a support cylinder, and a load in the rotational direction is applied to the support cylinder by the frictional force between the two.

[Problem that the invention attempts to solve]

By the way, in the above-mentioned packaging paper, the load acting on the support tube is always constant, so as the diameter of the roll gradually decreases, the tension of the paper unwound from the roll gradually increases, causing the paper to break. There are other inconveniences.

Therefore, the technical problem of this invention is to solve the above-mentioned disadvantages and to maintain the tension of a sheet such as a rolled or rewound paper substantially constant.

[Means for solving problems]

In order to solve the above problems, this invention has an electromagnet mounted on the outside of a non-rotationally supported support shaft, and a rotatable roll support cylinder fitted around the support shaft to cover the electromagnet. An adsorbent is placed opposite to the electromagnet, the adsorbent is movable in the axial direction of the roll support tube, and supported non-rotatably with respect to the roll support tube, and the adsorbent is pressed toward the electromagnet. A plurality of winding diameter detectors are arranged in the radial direction of the sheet roll on the sides of the sheet roll that is fitted on the outside of the roll support tube and rotates together with the roll support tube. The structure is such that the magnetic force of the electromagnet is adjusted based on the detection signal.

[Effect]

In the sheet tension adjustment device with the above configuration, when the electromagnet is energized, the electromagnet attracts the adsorbent, so a load can be applied in the rotational direction of the roll support cylinder, and the sheet tension is applied to the sheet pulled out from the sheet roll. The required tension can be applied.

When the amount of sheets pulled out increases and the winding diameter of the sheet roll gradually decreases, a plurality of winding diameter detectors arranged in the radial direction of the sheet roll operate sequentially from the outer diameter side. The value of the current flowing through the electromagnet is controlled by the detection signal from the roll diameter detector, and as the roll diameter becomes smaller, the magnetic force of the electromagnet becomes weaker. Therefore, the load acting on the roll support tube changes depending on the roll diameter, and the tension of the sheet rewound from the roll can always be kept substantially constant.

〔Example〕

Hereinafter, embodiments of this invention will be described based on the accompanying drawings.

As shown in the figure, a circular electromagnet 3 is attached to the outside of a support shaft 2 whose end is supported by a frame 1 of a drug packaging machine or the like. A roll support cylinder 4 fitted around the support shaft 2 so as to cover the electromagnet 3 is rotatably supported by a bearing 5.

A storage hole 6 in the roll support tube 4 in which the electromagnet 3 is accommodated is formed to have a large diameter, and an adsorbent 7 made of a magnetic material such as an iron plate is disposed between the end face of the storage hole 6 and the electromagnet 3. A plurality of rods 8 are provided on the surface of the suction body 7 facing the end surface of the storage hole, and each rod 8 is inserted into a guide hole 9 formed in the end surface of the storage hole 6 to move the suction body 7 in the axial direction of the support cylinder. movably and non-rotatably supported with respect to the support tube 4;
A spring 1 is inserted between the adsorbent 7 and the end face of the storage hole 6.
0 is incorporated, and the adsorbent body 7 is pressed against the electromagnet 3 by this spring 10.

Additionally, a radial hole 1 is provided at the end of the roll support tube 4.
1 is formed, and a ball 12 and a spring 13 that presses the ball 12 outward are housed in the hole 11, and the ball 12 is prevented from coming off with a portion protruding from the hole 11.

Furthermore, a flange 1 is provided on the end surface of the roll support tube 4.
4 is attached, and a permanent magnet 15 is attached to the outer periphery of one side of the flange 14.

The sheet roll 16 fitted on the outside of the roll support cylinder 4 can be freely inserted into and removed from the roll support cylinder 4, and is fitted on the outside of the roll support cylinder 4 so that the end face of the core 17 contacts the flange 14. Then, the magnetic plate 18 provided on the end face of the core is connected to the permanent magnet 1.
5, and the collar 19 provided at the end of the inner circumferential surface of the core 17 engages with the ball 12, and the sheet roll 16 rotates together with the roll support cylinder 4 due to the attraction, and the attraction and engagement The sheet roll 16 is prevented from coming off by both actions.

A light reflection type sheet presence/absence detector 20 is provided on the side of the sheet roll 16. Also,
A plurality of light-reflecting winding diameter detectors 21 are provided on the sides of the sheet roll 16 in the roll diameter direction, and a current flowing through the electromagnet 3 is caused to flow through the electromagnet 3 in response to a detection signal from each winding diameter detector 21. The electromagnetic force is controlled in stages according to the number of rollers 21, and as the roll diameter becomes smaller, the electromagnetic force becomes weaker.

Now, when the electromagnet 3 is energized, the electromagnet 3 attracts the adsorbent 7, so a load is applied to the roll support tube 4 in the rotational direction, and the magnitude of the electromagnetic force is increased against the sheet 16' pulled out from the sheet roll 16. A suitable tension can be applied.

When the roll diameter gradually decreases as the sheet 16' is pulled out, a plurality of winding diameter detectors 21 arranged in the radial direction of the roll are sequentially activated from the outside, and a detection signal from the detectors 21 causes the electromagnet 3 to be activated. The electromagnetic force gradually weakens. Therefore, the load on the roll support cylinder 4 in the rotational direction is gradually reduced, and the sheet 1 pulled out from the sheet roll 16
The tension of the sheet 6' is controlled according to the roll diameter, and the sheet tension can be kept almost constant.

〔effect〕

As described above, according to this invention, when the roll diameter of a sheet roll becomes small, a plurality of winding diameter detectors arranged in the radial direction of the roll on the sides of the sheet roll operate sequentially from the outside, and the winding diameter The electromagnetic force of the electromagnet that applies a load in the rotational direction of the roll support cylinder is gradually weakened based on the detection signal from the detector, so the load in the rotational direction of the roll support cylinder is reduced in response to changes in the roll diameter. is gradually reduced, and the tension of the sheet pulled out from the sheet roll can be managed to be almost constant. For this reason,
It is possible to prevent the occurrence of inconveniences such as sagging or cutting of the sheet.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the tension adjusting device according to the invention, and FIG. 2 is a side view of the same. 2... Support shaft, 3... Electromagnet, 4... Roll support tube, 7... Adsorption body, 10... Spring, 16
... Sheet roll, 21 ... Winding diameter detector.

Claims (1)

[Scope of utility model registration request] An electromagnet is attached to the outside of a non-rotating support shaft, and an adsorbent is placed inside a roll support cylinder that is rotatably fitted around the support shaft, facing the electromagnet, and the adsorbent is attached to the roll. The support cylinder is movable in the axial direction and supported non-rotatably with respect to the roll support cylinder, and a spring is provided that presses the adsorbent toward the electromagnet, and is fitted on the outside of the roll support cylinder to support the roll. On the sides of the sheet roll that rotates with the cylinder, multiple winding diameter detectors are arranged in the radial direction of the sheet roll, and the magnetic force of the electromagnet is adjusted based on the detection signal from each detector. Device.