Exercise machine

An exercise machine comprising:

• a weight stack composed of a plurality of separate weights vertically disposed with respect to each other;
• a lift bar disposed for vertical movement with the stack;
• and,
• pin means for removably securing a desired portion of the weight stack to the lift bar for vertical movement therewith, whereby the total weight carried by the lift bar is determined by the portion of the weight stack removably secured to the lift bar by the pin means;
• said pin means including at least one pin operated by an actuator, said pin being movable by its actuator over a predetermined stroke, said actuator including first means for positively moving the pin to an extended position to removably secure a portion of the weight stack to the lift bar, the actuator first means including first electrically operable means for positively moving the pin to the extended position, said actuator means further including second means for positively moving the pin to a retracted position in which the corresponding portion of the weight stack is free of the lift bar, the actuator second means including second electrically operable means for positively moving the pine to retracted position.

An exercise machine comprising:

• a weight stack composed of a plurality of separate weights vertically disposed with respect to each other;
• a lift bar disposed for vertical movement with the stack;
• and
• pin means for removably securing a desired portion of the weight stack to the lift bar for vertical movement therewith, whereby the total weight carried by the lift bar is determined by the portion of the weight stack removably secured to the lift bar by the pin means;
• said pin means including at least one pin operated by an actuator, the actuator including a pair of longitudinally spaced magnets operatively connected to the pin and a pair of electrical coils disposed to operatively interact with the magnets to apply net force to the pin for positively moving the pin to an extended position to removably secure a portion of the weight stack to the lift bar, and for positively moving the pin to a retracted position in which the corresponding portion of the weight stack is free of the lift bar.

An exercise machine comprising:

• a weight stack composed of a plurality of separate weights vertically disposed with respect to each other;
• a lift bar disposed for vertical movement with the stack;
• and
• pin means for removably securing a desired portion of the weight stack to the lift bar for vertical movement therewith, whereby the total weight carried by the lift bar is determined by the portion of the weight stack removably secured to the lift bar by the pin means;
• said pin means including at least one pin operated by an actuator, said pin being movably by its actuator over a predetermined stroke, said actuator including first means for positively moving the pin to an extended position to removably secure a portion of the weight stack to the lift bar, said first means for positively moving the pin to the extended position including an electrical coil wound in a first sense about the longitudinal axis of the pin, said actuator means further including second means for positively moving the pin to a retracted position in which the corresponding portion of the weight stack is free of the lift bar,
• the second means for positively moving the pin to the retracted position including a second electrical coil wound in the sense opposite to the first sense about the longitudinal axis of the pin.