Desk-top cutting machine
First Claim
Patent Images
1. A desk-top cutting machine, comprising:
- a base for supporting a workpiece;
a cutting blade portion which is provided above said base so as to be swingable vertically against said base, said cutting blade portion including a cutting blade, a motor and a driving force transmitting means for transmitting the driving force of said motor to said cutting blade, said driving force transmitting means including an endless belt;
soft start means for slowly boosting the rotation of said motor when starting said motor to control the torque of said motor during acceleration;
rpm detecting means for detecting one of the rpm of said motor and said cutting blade;
load current detecting means for detecting the load current of said motor;
motor control means which receives signals from said rpm detecting means and said load current detecting means during motor driving to control the rpm and torque of said motor so that the rpm and torque thereof do not exceed a permissible rpm and permissible transmission torque of said endless belt, respectively; and
braking means for stopping the rotation of said motor by a deceleration torque which does not exceed the permissible transmission torque of said endless belt when power supply to said motor is stopped.
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Accused Products
Abstract
In a desk-top cutting machine, a magnet 24 and a magnetic pickup 22 are attached to a motor shaft 12. A control circuit 28 is provided for controlling a TRIAC 23 in response to the signal from the detection means. Further, a dynamic braking coil 25 which serves as braking means for a motor 11 when power supply to the motor 11 is stopped is provided in the motor 11. The dynamic braking coil 25 stops within a time during which no slip is produced between the motor shaft 12 and endless belt 18 and between the cutting blade shaft 10 and endless belt 18. In this way, the rpm and torque of the motor are controlled from motor starting to cutting and motor stopping.
104 Citations
5 Claims
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1. A desk-top cutting machine, comprising:
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a base for supporting a workpiece; a cutting blade portion which is provided above said base so as to be swingable vertically against said base, said cutting blade portion including a cutting blade, a motor and a driving force transmitting means for transmitting the driving force of said motor to said cutting blade, said driving force transmitting means including an endless belt; soft start means for slowly boosting the rotation of said motor when starting said motor to control the torque of said motor during acceleration; rpm detecting means for detecting one of the rpm of said motor and said cutting blade; load current detecting means for detecting the load current of said motor; motor control means which receives signals from said rpm detecting means and said load current detecting means during motor driving to control the rpm and torque of said motor so that the rpm and torque thereof do not exceed a permissible rpm and permissible transmission torque of said endless belt, respectively; and braking means for stopping the rotation of said motor by a deceleration torque which does not exceed the permissible transmission torque of said endless belt when power supply to said motor is stopped. - View Dependent Claims (2, 3, 4, 5)
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Specification