초록 ▼

A roller drive mechanism for an automotive HVAC film valve belt includes a single motor type drive that automatically compensates for continually differing belt wind up and wind off rates, while maintaining at least a minimal belt tension, and without the necessity for precise adjustment. A central

A roller drive mechanism for an automotive HVAC film valve belt includes a single motor type drive that automatically compensates for continually differing belt wind up and wind off rates, while maintaining at least a minimal belt tension, and without the necessity for precise adjustment. A central motor drive shaft is split between a fixed end and a yieldable, slidable end. The two ends can turn at the same rate from the single motor, but the ability of the second end to slide back and forth allows one roller to match its belt handling rate to the other roller automatically, while the always stretched spring maintains a certain minimum belt tension, while also accommodating adjustment tolerances.

대표청구항 ▼

[ I claim:] [1.] A compensating tensioning mechanism for moving a film belt back and forth, comprising in combination,a first roller and a second roller having a length of belt wound on and between the roller, and adapted to alternately wind up and wind out the belt to move the belt back and forth b

[ I claim:] [1.] A compensating tensioning mechanism for moving a film belt back and forth, comprising in combination,a first roller and a second roller having a length of belt wound on and between the roller, and adapted to alternately wind up and wind out the belt to move the belt back and forth between the rollers, so that rotation of the rollers relatively apart tends to increase belt tension and rotation of the rollers relatively together tends to decrease belt tension,a rotating torque transmission mechanism having a shaft lying on a common shaft axis and adapted at respective ends of the shafts to concurrently rotate the rollers back and forth in the same direction as the shaft rotates in either direction, so as to alternately wind up and wind out the belt, anda torsionally stiff but axially yieldable tension means in the transmission mechanism lying between the shaft ends, said tension means is under least stretch when the belt is in a mid position and wound substantially equally onto each roller, the tension means also being adapted to be stretched farther in response to a greater belt tension, and thereby allow the two shaft ends to move relatively apart to in turn allow the two rollers to rotate relatively together,whereby, starting from the mid position, as the torque transmission mechanism rotates at a substantially constant rate so as to rotate the shaft in either direction and cause either roller to wind up more belt as the other roller winds off more belt, and as the roller winding up accumulates a thicker layer of belt that the roller winding off, so as to increase the instantaneous belt wind up rate and thereby increase the belt tension, the axially yieldable tension means can stretch beyond said mid position so as to allow the two shaft ends to rotate at differing rates and thereby allow the rollers to match respective wind up and wind out rates.