Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
387 words
In a hoist apparatus having a generally upwardly extending tower, a rack secured to the tower, and a lifting frame operatively connected to the tower for generally vertical movement along the tower, drive means on the frame for moving the frame along the tower, bearing means mounted on the frame, a shaft rotatably supported by the bearing means at at least a pair of axially spaced locations. a brake pinion mounted on the shaft for rotation therewith and engaging the rack, the bearing means including a pair of axially spaced support flanges extending generally transversely to the shaft, each flange having a substantially cylindrical surface which is eccentrically related to the longitudinal axis of the shaft, the frame being provided with a pair of generally circular openings which rotatably receive the cylindrical surfaces of the support flanges, and means for releasably securing the bearing means to the frame whereby the position of the axis of the shaft relative to the frame can be changed by releasing the securing means and rotating the cylindrical surfaces of the support flanges within the frame openings, a brake drum mounted on the shaft for rotation therewith, a brake band extending around a portion of the brake drum and having a pair of ends, one end of the brake band being secured to the frame, a plunger reciprocably mounted on the frame and connected to the other end of the brake band, a spring acting on the plunger for biasing the plunger to tighten the brake band about the brake drum, a latch pivotally mounted on the frame for holding the plunger against the bias of the spring, and centrifugal weight means pivotally mounted on the brake drum and movable outwardly under the influence of centrifugal force as the brake drum rotates, the brake pinion being rotated by the rack as the frame moves along the tower whereby the shaft and the brake drum are rotated, the centrifugal weight means being engageable with the latch when the centrifugal weight means pivot outwardly whereby the latch is pivoted to release the plunger when the rotational speed of the brake drum exceeds a predetermined value whereby the brake band will be tightened about the brake drum to stop the shaft and the brake pinion and thereby stop movement of the frame aloNg the tower.
Claim 2
Dependent Claim
387 words
In a hoist apparatus having a generally upwardly extending tower, a rack secured to the tower, and a lifting frame operatively connected to the tower for generally vertical movement along the tower, drive means on the frame for moving the frame along the tower, bearing means mounted on the frame, a shaft rotatably supported by the bearing means at at least a pair of axially spaced locations. a brake pinion mounted on the shaft for rotation therewith and engaging the rack, the bearing means including a pair of axially spaced support flanges extending generally transversely to the shaft, each flange having a substantially cylindrical surface which is eccentrically related to the longitudinal axis of the shaft, the frame being provided with a pair of generally circular openings which rotatably receive the cylindrical surfaces of the support flanges, and means for releasably securing the bearing means to the frame whereby the position of the axis of the shaft relative to the frame can be changed by releasing the securing means and rotating the cylindrical surfaces of the support flanges within the frame openings, a brake drum mounted on the shaft for rotation therewith, a brake band extending around a portion of the brake drum and having a pair of ends, one end of the brake band being secured to the frame, a plunger reciprocably mounted on the frame and connected to the other end of the brake band, a spring acting on the plunger for biasing the plunger to tighten the brake band about the brake drum, a latch pivotally mounted on the frame for holding the plunger against the bias of the spring, and centrifugal weight means pivotally mounted on the brake drum and movable outwardly under the influence of centrifugal force as the brake drum rotates, the brake pinion being rotated by the rack as the frame moves along the tower whereby the shaft and the brake drum are rotated, the centrifugal weight means being engageable with the latch when the centrifugal weight means pivot outwardly whereby the latch is pivoted to release the plunger when the rotational speed of the brake drum exceeds a predetermined value whereby the brake band will be tightened about the brake drum to stop the shaft and the brake pinion and thereby stop movement of the frame aloNg the tower.
Claim 3
Dependent Claim
50 words
The structure of claim 1 in which the plunger is connected to the other end of the brake band by a bell crank rotatably mounted on the frame, the latch being releasably engageable with the bell crank to prevent rotation of the bell crank under the bias of the spring.
Claim 4
Dependent Claim
59 words
The structure of claim 1 in which the plunger is reciprocably mounted within a cylinder and includes a piston within the cylinder, a fluid pump mounted on the frame, a fluid conduit communicating the pump and the cylinder whereby the piston and the plunger can be retracted against the bias of the spring by pumping fluid into the cylinder.