A motion retarder particularly useful for regulating rotary movement of a shaft, for example, includes an inner and outer tension unit carried on a bolt shaped rod. Arcurate end segments of a pressure member of each unit are positioned in an opposing manner to define a pair of shaft holding spaces. A spring carried on the rod between the inner unit and a head portion of the rod may be advanced through a threaded connection between an end of the rod and a lock-type nut forming part of the outer unit. This advancement compresses the spring to force an inner friction surface of the unit pressure member end segments into engagement with an outer surface of a shaft positioned in the respective holding spaces. This engagement selectively inhibits inadvertent shaft movement to maintain the position of the shaft until shaft movement is desired.
A railroad hopper car discharge gate is assembled from unitary stacked frames that provide unimpeded flow of lading during discharge. A low-wear glide system minimizes friction between the gate panels and other components of the apparatus, and an improved sealing system protects lading from contaminants such as rain, dust and insect infestation and provides enhanced vacuum sealing for greater efficiency during vacuum discharge.
A drive system for a railway hopper car discharge gate includes a door panel operated by a rack and pinion drive. The pinion teeth present a substantially cylindrical profile in a plane orthogonal to the axis of pinion rotation. The cylindrical tooth profile substantially prevents the pinion teeth from skipping or walking against the rack teeth when the spacing between the pinion and the door panel and associated rack fluctuates during operation of the discharge gate. Pinion torque is converted into a vertical force at the ends of travel of the door panel to prevent damage to the drive components. A bearing arrangement supports a drive shaft that is operated to rotate the pinions, and minimizes deflection of the shaft when under rotational load. An inertia brake is provided to engage the door panel and prevent it from opening upon a rapid stop of the hopper car as may occur upon impact with an adjacent railway car.
