Power loom dobby shedding motion

A power loom dobby shedding mechanism of the type having multiple arms mounted on pivot shaft means and connected respectively to operate the lift levers of conventional heddle or warp frames when the arms are oscillated about the axis of the pivot shaft means, and the mechanism having multiple pairs of cams mounted for rotation with a drive shaft of the dobby, the cams of each pair being spaced apart along the axis of the drive shaft and having respective peripheral races disposed in opposed relationship to an arm, and each arm having two follower rollers rotatably supported thereon on different sides of said pivot shaft means and respectively contacting different races of an opposed pair of cams, and the races of each pair of cams being mutually shaped and positioned about the axis of the drive shaft so that rotation of the shaft causes oscillation of the arms, the improvements wherein:

• each arm comprises a thin flat member located opposite the cams of the associated pair and within the axial extent of their races;
• first and second pairs of strips, the strips in each pair being fixed to opposite sides of the arm and each pair of strips extending toward and beyond the peripheries on opposite sides of a race and each pair of strips supporting rotationally a follower roller therebetween and in contact with one of said races, the first and second pairs being mutually offset axially of the shaft means in different directions so that each pair engages a different cam;
• the follower rollers having axial thicknesses greater than the cams, and the outer ends of each pair of strips beyond the roller being formed toward and then away from each other to provide surfaces riding on the sides of the cams to keep the follower rollers centered on the races.