GB2167820A - Centrifugal brake - Google Patents

Abstract

A Centrifugal brake comprises a rotatable shaft 1, and a spool 9 fixed to said shaft, via worm gear 14-18, for rotation therewith relative to a stationary brake drum 12. Rotation of the shaft and spool causes bobweights 10 to pivot (on pins 19) radially outwardly under centrifugal force into braking engagement with the drum. Such radially outward movement is restrained by a torsion spring 5, and variation of the torsional force effected by actuation of the worm gear so as to rotate the spool relative to the shaft 1 will alter the overall braking effect. <IMAGE>

Description

SPECIFICATION Variable resistance centrifugal brake This invention comprises the following pieces: Torque input shaft (1). Spring anchor bush, lock pin and anchor pin (2), (3) and (4). Torsion spring (5). Spool and sleeve assembly (9). Worm bracket and lockpin (14) and (15).

Worm (16). Worm gear and lockpin (17) and (18). Brake drum and ball bearing (12) and (13). Bobweights and friction linings (10) and (11). Bobweight pivot pins (19). The bobweights have pins (8) which project through slots in spool side plate and engage in slots in bar and bush assembly (6). The mechanism is housed in a casing (not shown) apart from the worm gear which is accessible from outside.

OPERA TION The rotation of shaft (1) is transmitted to the spool assembly (9) through worm gear and worm (16) and (17). The spool assembly is a running fit over shaft (1). The bobweights (10) move out radially due to centrifugal force and are restrained by the slotted bar (6) bearing on pins (8). The movement of bar (8) is controlled by torsion spring (5) and it wili be apparent that by varying the position of the worm gears that the torsional preload on spring (5) can be adjusted and thus alter the overall braking effect of the unit.

1. A Torque Adjustment Mechanism for a centrifugal brake wherein a projecting pin from a centrifugal member operates against a force from a torsion spring co-axial with a central drive shaft. A worm wheel is attached to one end of the central drive shaft and the pivot for the centrifugal member is fitted to a sleeve free to rotate over the central shaft. A worm is installed on the sleeve to engage with the wheel on the central shaft. The sleeve and central shaft are free to rotate in a stationary brake drum and the torsion spring is anchored to the central shaft.

2. A Torque Adjustment Mechanism as in (1) wherein the torsion spring is replaced by tension or compression springs anchored to the pin and sleeve to operate in an equivalent manner.

3. A Torque Adjustment Mechanism as in (1) and (2) wherein the worm gears are replaced by an equivalent spur gear system.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Variable resistance centrifugal brake This invention comprises the following pieces: Torque input shaft (1). Spring anchor bush, lock pin and anchor pin (2), (3) and (4). Torsion spring (5). Spool and sleeve assembly (9). Worm bracket and lockpin (14) and (15). Worm (16). Worm gear and lockpin (17) and (18). Brake drum and ball bearing (12) and (13). Bobweights and friction linings (10) and (11). Bobweight pivot pins (19). The bobweights have pins (8) which project through slots in spool side plate and engage in slots in bar and bush assembly (6). The mechanism is housed in a casing (not shown) apart from the worm gear which is accessible from outside. OPERA TION The rotation of shaft (1) is transmitted to the spool assembly (9) through worm gear and worm (16) and (17). The spool assembly is a running fit over shaft (1). The bobweights (10) move out radially due to centrifugal force and are restrained by the slotted bar (6) bearing on pins (8). The movement of bar (8) is controlled by torsion spring (5) and it wili be apparent that by varying the position of the worm gears that the torsional preload on spring (5) can be adjusted and thus alter the overall braking effect of the unit. CLAIMS

1. A Torque Adjustment Mechanism for a centrifugal brake wherein a projecting pin from a centrifugal member operates against a force from a torsion spring co-axial with a central drive shaft. A worm wheel is attached to one end of the central drive shaft and the pivot for the centrifugal member is fitted to a sleeve free to rotate over the central shaft. A worm is installed on the sleeve to engage with the wheel on the central shaft. The sleeve and central shaft are free to rotate in a stationary brake drum and the torsion spring is anchored to the central shaft.

2. A Torque Adjustment Mechanism as in (1) wherein the torsion spring is replaced by tension or compression springs anchored to the pin and sleeve to operate in an equivalent manner.

3. A Torque Adjustment Mechanism as in (1) and (2) wherein the worm gears are replaced by an equivalent spur gear system.