JP2008119812A - Cutting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting machine capable of performing stable cutting work by keeping a rotating driving force of a rotary cutter constant for preventing damages caused by overload of a motor and by preventing failure of the rotary cutter even when a large force is applied to a side surface of the rotary cutter. <P>SOLUTION: The cutting machine comprises a base for fixing and setting material to be cut, an arm rotatably supported by the base, a motor provided on the arm, and the rotary cutter 12 mounted to an output shaft 11 of the motor. In the cutting machine, the rotary cutter 12 is nipped by two flanges 14, 15 inserted into the output shaft 11 of the motor. A coil spring (elastic body) 17 is compressed between a fastening member 16 fastened to an end part of the output shaft 11 and the flanges 14, 15 so as to nip and hold the rotary cutter 12 with the flanges 14, 15 receiving compressive reaction of the coil spring 17. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cutting machine that rotates a rotary blade to cut a material to be cut.

  This type of cutting machine includes a base for fixedly setting a material to be cut, an arm rotatably supported on the base, a motor provided on the arm, and a rotary blade attached to an output shaft of the motor. It is comprised including.

  Here, FIG. 4 shows a structure for attaching the rotary cutter 112 to the motor output shaft 111 in the conventional cutting machine. The rotary cutter 112 is inserted into the small diameter portion 111a at the tip of the motor output shaft 111, and the rotary cutter 112 is inserted into 2 pieces. Rotating by clamping a fastening member 116 such as a bolt with a flange to the end of the motor output shaft 111 with one flange 114 being abutted against the stepped portion 111 b of the motor output shaft 111 while being sandwiched between the flanges 114, 115. The blade 112 was sandwiched between two flanges 114 and 115 and attached to the motor output shaft 111.

Thus, the rotary blade 112 is rotated together with the motor output shaft 111 by the frictional force generated between the rotary blade 112 and the flanges 114 and 115 and is used for cutting the material to be cut.
JP 2005-138238 A

  As described above, the conventional cutting machine employs a configuration in which the flanges 114 and 115 that sandwich the rotary blade 112 from both sides are directly fixed by the fastening member 116. The frictional force generated between the flanges 114 and 115 changes greatly, and accordingly, the rotational driving force transmitted from the motor to the rotary blade 112 also changes greatly.

  For example, when the fastening force of the fastening member 116 is weak, the frictional holding force of the rotary blade 112 becomes weak and the rotational driving force transmitted to the rotary blade 112 becomes small, so that a large cutting force is applied to the workpiece. Can not be done, cutting time will be longer.

  On the contrary, when the fastening member 116 is strongly tightened, the frictional holding force of the rotary blade 112 is increased and the rotational driving force transmitted to the rotary blade 112 is increased, so that a large cutting force can be applied to the workpiece. Although the cutting time can be shortened, a large current is supplied to the motor, so that the motor is overloaded and the motor generates heat and burns out.

  Further, as shown in the partial plan view of FIG. 5, when the workpiece W is cut obliquely, the workpiece W is pulled in the rotation direction of the rotary blade 112 by the rotational force of the rotary blade 112, and the base 102. In a case where the fixing force of the workpiece W by the upper fixed vise 103 and the moving vise 104 is weak, the workpiece W moves in the direction of arrow B in the figure, and a large load is applied to the rotary cutter 112 from the side. Sometimes. In such a case, since the rotary blade 112 is rigidly coupled to the motor output shaft 111, the rotary blade 112 receives the load as it is without escaping the load from the side surface direction, and the rotary blade 112 is deformed, In the worst case, the rotary blade 112 may be damaged.

  The present invention has been made in view of the above problems, and the object of the present invention is to keep the rotational driving force of the rotating blade constant to prevent damage due to overload of the motor and to apply a large force to the side surface of the rotating blade. It is an object of the present invention to provide a cutting machine that can perform a stable cutting operation while preventing damage to the rotary blade.

  In order to achieve the above-mentioned object, the invention according to claim 1 includes a base for fixing and setting a material to be cut, an arm rotatably supported on the base, a motor provided on the arm, In a cutting machine configured to include a rotary cutter attached to an output shaft, the rotary cutter is sandwiched by two flanges inserted through the output shaft of the motor, and fastened to the end of the output shaft An elastic body is mounted between the member and the flange, and the rotary blade is sandwiched by the flange that receives the compression reaction force of the elastic body.

  According to a second aspect of the present invention, in the first aspect of the present invention, the elastic body is configured by a coil spring.

  According to the present invention, the rotational driving force of the motor is transmitted to the rotary blade by the frictional force generated between the flange and the rotary blade by the pressing force of the elastic body, and the rotary blade rotates together with the output shaft. Since the pressing force (compression reaction force) is kept constant, the rotational driving force of the rotary blade is also kept constant. For this reason, for example, even if an attempt is made to cut with an excessive force in order to shorten the cutting time, slippage occurs between the flange and the rotary blade, preventing overloading of the motor and reliably preventing damage due to overheating of the motor. The cutting work can be performed stably at all times.

  In addition, even when a large force is applied to the side surface of the rotary blade due to the material being cut, etc., a gap is generated between the flange and the rotary blade due to elastic deformation of the elastic body, and the rotary blade escapes sideways. As a result, it is possible to reliably prevent the rotary blade from being damaged.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 is a front view of a cutting machine according to the present invention, FIG. 2 is an enlarged sectional view taken along line AA of FIG. 1, and FIG. 3 is a view similar to FIG. 2 showing a state when a load is applied to the side surface of the rotary blade. It is.

  On the base 2 of the cutting machine 1 shown in FIG. 1, a fixed vise 3 and a moving vise 4 for fixing and setting a workpiece W such as a pipe as shown in the figure are provided. Here, the moving vise 4 is movable along a guide groove (not shown) formed on the upper surface of the base 2 along the longitudinal direction (left-right direction in FIG. 1), and is a screw shaft rotated by the handle 5. 6 is connected to the tip.

  Accordingly, the workpiece W is placed between the fixed vise 3 and the moving vise 4 on the base 2, and the screw shaft 6 is rotated by the handle 5 to move the moving vise 4 along a guide groove (not shown) on the base 2. By moving the workpiece W, the workpiece W can be clamped between the fixed vise 3 and the movable vise 4 and fixed on the base 2 as shown in the figure.

A hinge 7 is erected on one end on the base 2, and one end of an arm 8 is supported on the upper end of the hinge 7 by a hinge shaft 9 so as to be rotatable up and down. The arm 8 is always urged by a return spring 10 wound around the hinge shaft 9 in a direction of rotating upward about the hinge shaft 9 (clockwise in FIG. 1). still,
One end of the return spring 10 is locked to the hinge 7, and the other end is locked to the arm 8.

  Further, a handle portion 8 a is provided at the other end portion (free end portion) of the arm 8, and a motor (not shown) as a drive source is supported in a horizontally placed state at an intermediate portion of the arm 8. A disc-shaped rotary cutter 12 is attached to the end of the output shaft 11 (see FIG. 2) extending in the lateral direction of the motor, and a substantially upper half of the rotary cutter 12 is covered with a protective cover 13. .

  Here, the attachment structure to the output shaft 11 of the rotary blade 12 is demonstrated based on FIG.

  As shown in FIG. 2, the two small flanges 14 and 15 and the rotary blade 12 are inserted into the small diameter portion 11 a of the output shaft 11, and the rotary blade 12 is sandwiched between the two flanges 14 and 15. . A fastening member 16 such as a bolt with a flange is attached to the end of the output shaft 11, and a coil spring that is an elastic body is provided between the fastening member 16 on the outer periphery of the small-diameter portion 11 a of the distal end of the output shaft 11 and the flange 15. 17 is shrunk.

  Accordingly, the flanges 14, 15 are pressed against the rotary blade 12 by the compression reaction force of the coil spring 17, and the rotary blade 12 is sandwiched between the two flanges 14, 15, and between the rotary blade 12 and the flanges 14, 15. A frictional force is generated with respect to the rotation, and the rotary blade 12 rotates together with the output shaft 11 by this frictional force. Here, since the compression length L of the coil spring 17 is constant, the compression reaction force of the coil spring 17 is also constant, and the rotary blade 12 is held between the flanges 14 and 15 with a constant force. For this reason, a constant frictional force is always generated with respect to the rotation between the rotary blade 12 and the flanges 14 and 15, and the rotary blade 12 rotates together with the output shaft 11 by this constant frictional force to cut the workpiece W. To be served.

  By the way, the rotary blade 12 is attached to the output shaft 11 in the following manner.

  That is, first, one flange 14 is passed through the tip small diameter portion 11 a of the output shaft 11, and the flange 14 is abutted against the step portion 11 b of the output shaft 11 to be positioned. Next, the rotary blade 12, the other flange 15 and the coil spring 17 are sequentially passed through the small diameter portion 11 a of the output shaft 11, and the rotary blade 12 is sandwiched between the flanges 14 and 15. Finally, the fastening member 16 is attached to the output shaft 11. When attached to the end, the attachment of the rotary blade 12 to the output shaft 11 is completed, and the rotary blade 12 is held between the flanges 14 and 15 with a constant force by the compression reaction force of the coil spring 17.

  As shown in FIG. 1, the workpiece W is fixedly set on the base 2, the arm 8 is lifted, and the rotary blade 12 is positioned above the workpiece W. When the switch is turned on and the motor is driven, the output shaft 11 and the rotary blade 12 attached thereto rotate at a predetermined speed.

  When the handle 8a is gripped from the above state and the arm 8 is rotated downward about the hinge shaft 9, the workpiece W is cut by the rotating rotary blade 12.

  By the way, in the above cutting operation, the rotational driving force of the motor is transmitted to the rotary blade 12 by the frictional force generated between the flanges 14 and 15 and the rotary blade 12 by the pressing force of the coil spring 17, thereby causing the rotary blade 12 to move. Although it rotates with the output shaft 11, since the compression length L of the coil spring 17 is kept constant as described above, the pressing force (compression reaction force) of the coil spring 17 is kept constant. 12 is sandwiched between the flanges 14 and 15 with a constant force. As a result, a constant frictional force is always generated with respect to the rotation between the rotary blade 12 and the flanges 14 and 15, and the rotational driving force transmitted to the rotary blade 12 is also kept constant by this frictional force. For this reason, for example, even if an attempt is made to cut with an excessive force in order to shorten the cutting time, slippage occurs between the flanges 14 and 15 and the rotary blade 12 to prevent overload of the motor, damage due to overheating of the motor, etc. Is reliably prevented, and the cutting operation can always be performed stably.

Here, if the cutting force in the motor overload state is F1, the cutting force that can be cut is F2, and the cutting force that cannot be cut (idle) is F3, between these cutting forces F1, F2, and F3,
F1>F2> F3 (1)
The magnitude relationship becomes true.

By the way, the cutting force F of the rotary blade 12 is such that the pressing force of the coil spring 17 is P, the friction coefficient between the flanges 14 and 15 and the rotary blade 12 is μ, the radius of the flanges 14 and 15 is r, and the radius of the rotary blade 12 is R. Then,
F = (P × μ × r) / R (2)
It becomes.

  Thus, since the friction coefficient μ, the radius r of the flanges 14 and 15, and the radius R of the rotary blade 12 are constant, the pressing force P of the coil spring 17 can cut the workpiece W, and Setting so that the rotary blade 12 does not idle (constant compression length L of the coil spring 17) and the cutting force F obtained by the equation (2) is set to F2, thereby preventing overload and idle rotation of the motor. be able to.

  Further, even when a large force is applied to the side surface of the rotary blade 12 because the workpiece W is displaced, as shown in FIG. 3, the coil springs 17 are elastically deformed to cause the flanges 14 and 15 and the rotary blade 12 to move. A gap is generated between them, and the rotary blade 12 can escape to the side. Therefore, the friction coefficient μ becomes zero, the rotary blade 12 does not rotate, and damage to the rotary blade 12 is reliably prevented.

  In the present embodiment, a coil spring is particularly used as the elastic body, but any other elastic body such as a disc spring can be used.

It is a front view of the cutting machine concerning the present invention. It is an AA line expanded sectional view of FIG. It is a figure similar to FIG. 2 which shows a state when a load is added to the side surface of a rotary blade. It is a fragmentary sectional view which shows the attachment structure to the output shaft of the rotary blade in the conventional cutting machine. It is a fragmentary top view which shows the mode of the diagonal cutting | disconnection with the conventional cutting machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cutting machine 2 Base 3 Fixed vice 4 Moving vice 5 Handle 6 Screw shaft 7 Hinge 8 Arm 8a Arm handle 9 Hinge shaft 10 Return spring 11 Output shaft 11a Output shaft tip small diameter portion 11b Output shaft step portion 12 Rotating blade 13 Protective cover 14, 15 Flange 16 Fastening member 17 Coil spring (elastic body)
W Material to be cut

Claims (2)

Cutting comprising a base for fixing and setting a material to be cut, an arm rotatably supported on the base, a motor provided on the arm, and a rotary blade attached to the output shaft of the motor In the machine
The rotary blade is sandwiched between two flanges inserted through the output shaft of the motor, and an elastic body is compressed between the flange and a fastening member fastened to an end of the output shaft, and the elastic body is compressed. A cutting machine characterized in that the rotary blade is clamped by the flange that receives a reaction force.   The cutting machine according to claim 1, wherein the elastic body is constituted by a coil spring.

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