JPH1086092A - Overload preventing method for sheet material cutting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power loss by interrupting a drive force by an elastic force of an elastic member in overload. SOLUTION: When an overload is generated in a cutter part caused by a jam or the like, a shaft, groove 10 which sandwiches an arm shaft 4 in the tip of a drive arm 3 of a connecting rod 8 is opened elastically and the arm shaft, 4 is detached therefrom in a slit 9 of the connecting rod 8. That is to say, a force applied thereon in overload deforms the connecting rod 8 as an elastic member so as to release the connection. Because the arm shaft, 4 slips in the slit 9 of the connecting rod 8, the rotational motion of the motor 5 side is not transmitted to a movable blade l so as to interrupt the drive force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus such as a facsimile or a copying machine for preventing overload of a cutter used for cutting sheet material (hereinafter simply referred to as "paper") such as recording paper or film. It is about the method.

[0002]

2. Description of the Related Art A paper cutting device comprising a reciprocating movable blade and a fixed blade receives power from a dedicated motor or a main motor of a machine, converts a rotary motion into a reciprocating motion, and converts the rotational motion into a reciprocating motion. introduce. However, if a jam (paper jam) occurs in the cutter section or a piece of metal is caught in the cutting edge, a large driving force may damage the cutting edge of the cutter or the components of the driving system. When the driving force is insufficient, the cutter stops in the middle of the stroke. In the case of the former, the blade cannot be recovered without replacing the blade due to chipping of the cutting edge, etc.In the case of the latter, there is a risk of heating the motor, and in order to remove the paper caught in the cutter, ,
The cutter must be returned to standby by manual operation.

In order to avoid such a problem, there is a method of incorporating a torque limiter on the driving side or controlling the motor current to control the transmission of torque more than necessary. However, it is difficult for a mechanism that converts rotary motion to reciprocating motion to convert a constant torque of rotary motion into a constant torque of reciprocating motion, and usually has a very large boosting effect near the upper and lower dead points. In addition, it is not sufficient for the purpose of suppressing the torque on the cutter side to a certain level or less. Therefore, in order to operate such a mechanism more completely, it is desirable to suppress power transmission after conversion into reciprocating motion to a certain level or less.

As a prior art employing such a mechanism, Japanese Utility Model Application No. 61-34745 (Japanese Utility Model Application Laid-Open No. 62-1474) is known.
No. 91) is known. Here, the transmission of the rotational motion of the cam to the reciprocating motion of the rotary blade by the four-bar linkage is performed by using both the support lever and the spring,
When the load exceeds a predetermined value, the spring expands to prevent transmission of excessive power.

[0005]

However, the mechanism described in the aforementioned Japanese Utility Model Application No. 61-34745 (Japanese Utility Model Application Publication No. Sho 62-147491) has the following disadvantages due to the use of a spring. is there. As is well known, a spring has a property of causing a certain ratio of elongation to a load. Because it is not possible to predict at which position in the cutting stroke the overload will occur on the movable blade of the reciprocating cutter,
If an excessive load occurs due to the occurrence of a jam at the beginning of cutting, the cutter mechanism of this structure rotates the driving shaft (motor shaft) while extending the spring until a predetermined stroke, and eventually ends. If an excessive load occurs at the start of cutting of the cutter, in addition to this load, the load corresponding to the extension of the spring during the stroke is transmitted.

On the other hand, for a load generated at the end of cutting of the cutter, the extension of the spring in the subsequent stroke is small. Will work. That is, in this mechanism, the magnitude of the load that can be suppressed varies depending on the position where the overload occurs, and this becomes a bottleneck for minimizing the required power and the drive system. In this mechanism, it is effective to reduce the spring constant in order to reduce the fluctuation of the load to be suppressed, but if a predetermined tension is obtained and the spring constant is to be reduced, the spring is large. This is disadvantageous in terms of the space occupied by the mechanism and the cost.

[0007]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages of the prior art, the present invention provides a compact and power-loss device by cutting off the driving force by the elastic force of the elastic member when overloaded. The present inventors have found that a method for preventing overload is small, and have reached the present invention. That is, the present invention is an overload prevention method for a sheet material cutting device that cuts a sheet by reciprocating a movable blade with respect to a fixed blade, and constitutes a part of a driving force transmission member that transmits a driving force to the movable blade. An overload preventing method for a sheet material cutting device, characterized in that a connection member is released by a force applied when an overload is applied to the elastic member to cut off a driving force.

As a specific means, a split groove is provided in a connecting rod for power transmission, and a shaft for power transmission is elastically fitted into the shaft groove. This power transmission shaft can be configured to be out of the shaft groove.

[0009]

An important feature of the present invention is that the elastic member constituting a part of the driving force transmitting member is released from the connection by the force applied at the time of overload. That is, the elastic member is deformed by the force applied to the overloaded ground, and the connection is released to cut off the driving force. By using an elastic member, the connection can be released with a load more than a predetermined value, and even if an excessive load occurs at any position in the stroke of the movable blade of the cutter, the load more than the predetermined value is not transmitted to the cutter side. You can do it. Further, by using the elastic member, if the cause of the overload is removed after the connection is released, the connection can be re-established by the deformation of the elastic member.

FIG. 1 shows an embodiment of the present invention. A cutter composed of a movable blade 1 reciprocatingly rotating and a fixed blade 2 having its cutting edge pressed against the movable blade 1 includes a drive arm 3 attached to a shaft of the movable blade, an arm shaft 4 at the tip thereof, and a motor. 5 is connected to a rotor shaft 7 attached to a rotor 6 fixed to the shaft 5 by a connecting rod 8 having a split groove 9 which is open at one end. When the cutter operates normally, this mechanism becomes a normal 4-bar link mechanism,
The rotation of the motor 5 is transmitted to the drive arm 3 as a reciprocating rotation, and for one rotation of the motor, the movable blade 1
One operation of disconnect-return is performed.

Next, FIG. 2 shows a series of operations of the drive control section of the cutter of the present invention when the load on the cutter portion is abnormally increased due to a jam or the like. FIG. 2A shows a standby state. When an overload occurs, as shown in FIG. 2B, the shaft groove 10 sandwiching the arm shaft 4 at the tip of the drive arm of the connecting rod 8 opens elastically, and the arm shaft 4 is connected. It comes off in the split groove 9 of the rod 8. That is, the connection rod 8 which is an elastic member is deformed by the force applied at the time of overload, and the connection is released. The rotation of the motor after this is
As shown in FIG. 2C, since the arm shaft 4 slides in the split groove 9 of the connecting rod 8, it is not transmitted to the movable blade, and the driving force is cut off. When the rotation position of the rotor 6 reaches the return stroke, as shown in FIG. 2D, the arm shaft 4 starts rotating the drive arm 3 in the return direction. When the rotor 6 rotates and pushes the arm shaft 4 back to the position of the shaft groove 10, the drive control unit returns to the original standby state. Return to

Therefore, even when an overload occurs, the sheet material cutting apparatus to which the method of the present invention is applied is stopped when the cutter returns to the original standby state, thereby causing the jam causing the overload. It is possible to easily perform the operation of removing the paper and metal pieces that have been stacked. Also, no matter where the overload condition occurs on the cutter, the magnitude of the critical load that separates can be kept almost constant, so the power of the motor and the strength of the drive system are appropriately designed according to this load. It is possible to

FIG. 3 shows an embodiment in which the method of the present invention is applied to another sheet material cutting apparatus. The driving arm 3 of the movable blade and the rotor 6 on the driving shaft side are connected by a connecting rod 8 having a split groove 9, and the driving arm 3 is driven in a direction pulled by the rotor 6 via the connecting rod 8. In this case, at the time of overload, the arm shaft 4 comes off the connecting rod 8, so that the arm shaft 4 can return to a predetermined position of the shaft groove 10 of the connecting rod 8 during the return stroke. A guide portion 12 is provided at the tip of the rod 8. In this case, the drive arm can be driven in the pulling direction.
In combination with the embodiment shown in the above, the design of the drive system can be implemented by freely selecting pushing or pulling when viewed from the driving shaft side.

FIG. 4 shows still another embodiment of the present invention. A guide piece 13 having a C-shaped cross section is attached to the arm shaft 4 of the drive arm 3 so that the connecting rod 8 and the arm shaft 4 that have come off in the event of an overload are returned to their original state. It serves as a guide for the rod 8. In the case of such a mechanism, in the embodiment shown in FIG.
Since the sheet 2 does not reciprocate in a protruding state, the sheet material cutting apparatus can be made smaller.

FIG. 5 is a diagram showing another embodiment of the present invention. This embodiment is a guillotine type cutter comprising a fixed blade 2 having a straight blade edge and a movable blade 1 provided with a V-shaped blade and reciprocating up and down. In this embodiment, the rotation of the rotor 6 which is rotated by a motor (not shown) is controlled by the drive arm 3 and the connecting rod 8 having a split groove.
And is converted into a reciprocating motion of the movable blade 1. If an overload occurs due to a large number of sheets of paper entering the gap 15 between the fixed blade 2 and the movable blade 1, the overload on the motor side is automatically avoided by the action of the connecting rod 8.
Since the movable blade 1 is returned to the original standby position, compared to a case where the drive arm 3 is directly connected to the movable blade 1, there is no burning of the motor, and the operation for clearing the obstacle in the event of a jam becomes easier. It can be carried out.

In FIG. 5 of this embodiment, the shaft groove 10 provided in the connecting rod 8 has been described as being fitted into the pin 16 of the movable blade 1. Since the same operation can be performed even when the arm shaft 4 is fitted,
The direction of the set of the connecting rods 8 may be properly used depending on the application. The same can be said for the embodiment shown in FIG.

[0017]

According to the present invention, there is provided a sheet material cutting apparatus equipped with an overload prevention structure which is small in size and has low power loss by controlling driving by an elastic deformation portion.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a sheet material cutting device according to the present invention.

FIG. 2 is a front view of a drive connection portion showing the operation of the embodiment of FIG. 1 for each stroke.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 movable blade, 2 fixed blade, 3 drive arm, 4 arm axis, 5 motor, 6 rotor, 7 rotor axis, 8
Connecting rod, 90 split groove, 10 shaft groove, 11 locking part, 12
Guide part, 13 Guide piece, 14 Slot, 15 Gap, 1
6 pin

Claims (1)

[Claims] 1. An overload prevention method for a sheet material cutting device for cutting a sheet by reciprocating a movable blade with respect to a fixed blade, wherein the driving force transmitting member transmits a driving force to the movable blade. Due to the force applied to the elastic member during overload,
A method for preventing an overload of a sheet material cutting device, wherein the driving force is cut off by releasing the connection.