Hoist with constant pressure one way brake

Claim 2

A hoist having a main frame on which a hoist motor is mounted, an operating shaft rotated by the motor and acting through speed reduction gearing to apply high torque to a rotatable load shaft, the operating shaft being reversible in operation whereby to lift and to lower a load on the load shaft, a pair of opposed brake plates mounted in aligned relation to the axis of said operating shaft and secured against rotating motion relatively to the hoist frame, one plate of said pair of opposed brake plates being directly mounted to the frame of the hoist and having an opening for accepting an end portion on the operating shaft, friction material forming a pair of brake discs assembled in position intermediate said brake plates, spring means pressing said pair of brake plates and causing each of those plates to apply constant braking pressure against a surface of said brake discs, an overrunning clutch assembly on said end portion of said shaft, including a clutch housing forming a first and second keying member mounted adjacent to each other but angularly offset from each other, said first and second keying members Engaging key matching openings in said first and second brake discs respectively to provide contact between a portion of the adjacent surface of said first brake disc and said second keying member and between said second brake disc and said first keying member, a clutch part acting when said shaft rotates in load lowering direction to rotate said brake discs in slip friction relation to said pair of brake plates, and said one plate directly mounted to the frame of the hoist accepting a portion of the frictional energy that is due to the load lowering direction of said shaft being opposed by the effect of the constant braking pressure to dissipate the accepted portion of the frictional energy through the frame of the hoist.

Claim 3

The hoist construction as set forth in claim 1 wherein said first and second key members are a pair of adjacently mounted hexagonally shaped members angularly offset from each other and each of said brake discs being formed to have a hexagonally shaped opening allowing said brake discs to be fitted onto the first and second hexagonally shaped members.

Claim 4

In a hoist having a frame on which a hoist motor is mounted, an operating shaft rotated by the motor and acting through speed reduction gearing to apply high torque to a rotatable load shaft, the operating shaft being reversible in operation whereby to lift and to lower a load on the load shaft, the improvement that comprises a pair of opposed brake plates mounted in aligned relation to the axis of said operating shaft and secured against rotating motion relatively to the hoist frame, one plate of said pair of opposed brake plates having an opening for accepting an end portion on the operating shaft, friction material forming a brake disc assembled in position intermediate said brake plates, spring means pressing said pair of brake plates and causing each of those plates to apply constant braking pressure against a surface of said brake disc, an overrunning clutch on said end portion of said shaft, including a clutch part acting when said shaft rotates in load lowering direction to rotate said brake disc in slip friction relation to said pair of brake plates, each of those plates accepting a portion of the frictional energy that is due to the high speed of the operating shaft while opposed by the effect of the constant braking pressure, said overrunning clutch comprising a bushing keyed to said end portion of said operating shaft, and a clutch housing positioned in an opening in said brake disc, said housing being equipped with means in keying relation to said opening in the brake disc, including a hub integrally mounted on the clutch housing and having formed on its periphery portions in keying relation to the opening in the brake disc, said brake disc including a plurality of disc portions assembled in contacting relation with the keying portions on the clutch housing engaging an opening in each disc portion and being formed in a staggered relation engaging also contacting surfaces of opposed disc portions for holding the brake disc in a predetermined axial position relatively to the clutch housing.

Claim 5

In a hoist having a frame on which a hoist motor is mounted, an operating shaft rotated by the motor and acting through speed reduction gearing to apply high torque to a rotatable load shaft, the operating shaft being reversible in operation whereby to lift and to lower a load on the load shaft, the improvement that comprises a pair of opposed brake plates mounted in aligned relation to the axis of said operating shaft and secured against rotating motion relatively to the hoist frame, one plate of said pair of opposed brake plates having an opening for accepting an end portion on the operating shaft, friction material forming a brake disc assembled in position intermediate said brake plates, spring means pressing said pair of brake plates and causing each of those plates to apply constant braking pressure against a surface of said brake disc, an overrunning clutch on said end portion of said shaft, including a clutch part acting when said shaft rotates in load lowering direction to rotate said brake disc in slip friction relation to said pair of brake plates, each of those plates accepting a portion of the frictional energy that is due to the high speed of the operating shaft while opposed by the effect of the constant braking pressure, said overrunning clutch comprising a bushing keyed to said end portion of said operating shaft, and a clutch housing positioned in an opening in said brake disc, said housing being equipped with means in keying relation to said opening in the brake disc, including a hub integrally mounted on the clutch housing and having formed on its periphery portions in keying relation to the opening in the brake disc, said brake disc including a plurality of disc portions assembled in contacting relation with the keying portions on the clutch housing engaging an opening in each disc portion and being formed in a staggered relation engaging also contacting surfaces of opposed disc portions for holding the brake disc in a predetermined axial position relatively to the clutch housing.

Claim 6

The hoist construction set forth in claim 3 in which said hoist frame comprises an end wall against which said one plate of said pair of brake plates lies in longitudinal surface contact, and including means engaging between said frame end wall, said one brake plate, and the other of said brake plates to hold those plates against rotating motion relatively to the hoist frame.