Strength training control device using motor assembled beam-type load cell

1. A strength training control device using a motor assembled beam-type load cell, comprising:

a) a base frame;

b) a torque source, fixed onto the base frame, and comprising a motor and a gear reduction box, wherein the motor is a brushless motor or a DC motor, and an end of the gear reduction box is coupled to the motor, and another end of the gear reduction box includes a main shaft;

c) a drive arm having a depressing surface at the top of the internal side of the top end thereof and a flange at each side of the bottom end thereof, the flange having at the center thereof a shaft hole for slipping over the main shaft;

d) an operating rod with the bottom pivotally coupled to the base frame and serving as a control element for training a muscle of a user;

e) a link mechanism including:

i) a rocker arm with the bottom portion thereof mounted onto the operating rod such that it is driven by the operating rod;

ii) a front and a rear plate each having a central hole at the bottom thereof, respectively, such that they are pivotally coupled to the flanges at both sides of the drive arm; and

iii) a connecting rod with both ends pivotably and respectively coupled to the top of the rocker arm and the top of the front and rear plates, whereby, when the operating rod is activated, the rocker arm pulls or pushes the connecting rod to impart a rotary motion in the forward or the reverse direction to the front and rear plates;

f) a beam-type load cell secured to the side of the drive arm with one end thereof resting against the depressing surface, whereby, when the front and rear plates are reversely rotated, one end of the beam-type load cell rests against the drive arm to conduct a reverse rotation;

g) an electronic meter, fixed onto the base frame, and provided for a user to set a required torque value; and

h) a servo controller, for comparing the difference between a sensed value of the beam-type load cell and a set value of the electronic meter and after the difference value is adjusted, an electric current is output to drive the motor;

wherein the torque produced by the motor is amplified by the gear reduction box to adjust the actual torque value to the desired set value; and

wherein, when the user operating the operating rod, the beam-type load cell will be activated via the link mechanism to force it to conduct a reverse rotation on the drive arm such that the torque acts on the operating rod to create a load resistance and the muscle of the user is loaded by this resistance to achieve a desirable training effect.

2. The strength training control device using a motor assembled beam-type load cell as recited in claim 1 , wherein the servo controller comprises: a DC power supply, a load signal amplifier, a differential amplifier, a proportional-integral-derivative (PID) controller, and a DSP driver, and the sensed value of the beam-type load cell is fed back to the load signal amplifier, and the signal is amplified and then transmitted to the differential amplifier, and the set value of the electronic meter is transmitted to the differential amplifier, and then after the differential amplifier compares the difference between the load and the set value, the difference value is adjusted by the PID controller to drive the DSP driver to output an electric current to drive the motor.

3. The strength training control device using a motor assembled beam-type load cell as recited in claim 2 , further comprising a load fixing block which is secured between the front and rear plates by a plurality of screws, and wherein the bottom of the beam-type load cell is screwed on the load fixing block.

4. The strength training control device using a motor assembled beam-type load cell as recited in claim 3 , wherein an adjusting screw is screwed to the top of the beam-type load cell in such a way that the end portion of the adjusting screw rests against the depressing surface of the drive arm.

5. The strength training control device using a motor assembled beam-type load cell as recited in claim 4 , wherein a bearing block and a ball bearing fit into the central hole at the bottom of the front and rear plates, respectively, and wherein the bearing blocks are fixed by a plurality of screws onto the front and rear plates, and wherein the ball bearings are pivotably mounted on the flanges at both sides of the drive arm, and wherein a C-shaped retaining ring is positioned around the internal side of each flange to fix the ball bearing in place, whereby the front and rear plates are rotatably positioned on the flanges of the drive arm.

6. The strength training control device using a motor assembled beam-type load cell as recited in claim 5 , wherein the operating rod is separable in a left and a right rod onto which two flanged bases are mounted, and wherein the rocker arm is interposed between these two flanged bases and fixed by a plurality of bolts and nuts in place such that the rocker arm may swing back and forth with the operating rod.

7. The strength training control device using a motor assembled beam-type load cell as recited in claim 6 , wherein the rocker arm and the connecting rod are coupled by two cams which are fixed by a plurality of bolts and nuts in place.

8. The strength training control device using a motor assembled beam-type load cell as recited in claim 7 , further comprising a rod holder by which the operating rod pivotably mounted on the base frame.