GB2069966A - Winch driving arrangement - Google Patents

Abstract

A reversible differential gear comprising a drive spindle 2 an eccentric or cam 3 mounted on the spindle to rotate therethrough, an inner sprocket 4 mounted on the eccentric or cam, an outer sprocket wheel 5 loosely mounted on the spindle, a slide 6 fixedly mounted on the inner sprocket 4 and slidable in a recess 8 in a slide retaining plate 7 capable of a longitudinal movement and preventing the slide from rotation, the inner sprocket 4 moving one tooth over the outer sprocket at each revolution of the shaft and an output drive or sprocket integral with the outer sprocket 5 to provide a self sustaining reversible gear. <IMAGE>

Description

SPECIFICATION Improvements in differential gears This invention relates to improvements in nonreversible differential gears particularly application for motor vehicles for raising and lowering spare wheels on lorries and other purposes.

According to the invention the differential gear comprises a drive spindle, an eccentric or cam mounted on the spindle to rotate therewith, an inner sprocket wheel mounted on the cam or eccentric, an outer sprocket wheel loosely mounted on the spindle, a slide mounted on the inner sprocket in a recess in a slide retaining plate capable of a longitudinal movement and preventing the slide from rotation, the inner sprocket moving one or more teeth over the outer sprocket at each revolution of the shaft and an output drum of sprocket integral with the outer sprocket to provide a non-reversible reduction drive.

The invention will be described with reference to the accompanying drawings:- Fig. 1 is a side elevation of the gear; Fig. 2 is a vertical section on line 2-3 Fig. 1; Fig. 3 is a section on line 3-3 Fig. 2; Fig. 4 is an exploded perspective view of the working parts with the casing omitted.

The differential gears are assembled in a casing or gear box 1 with an eccentric input spindle 2 journaled therein. A cam or eccentric 3 is mounted on the spindle with an inner sprocket 4 mounted on the cam forming an inner sprocker assembly.

An outer sprocket 5 having internal teeth, is loosely mounted on the spindle and is integral with an output sprocket assembly. These two subassemblies i.e., an inner sprocket assembly and outer sprocket assembly are arranged so that they are constantly in mesh with each other due to the cam throw, when the shaft is rotated.

A slide 6 which is part of the inner sprocket assembly is located in a slide retaining plate 7 and is allowed to move in a slot 8 in the retaining plate 7, an amount which represents the maximum lateral movement of the cam 3. The slide retaining plate 7 is free to move up and down a distance which represents the maximum vertical movement of the cam 3.

Having therefore accommodated the total cam movement it is possible to rotate the cam spindle 2.

The slide retaining plate 7 is not allowed to rotate and therefore because the slide of the inner sprocket sliding plate 6 is located in the slot 8 in the retaining plate 7 the inner sprocket 4 assembly also cannot rotate, but instead drive the outer sprocket 5 assembly in a clockwise direction when the cam spindle 2 is rotated clockwise and in the opposite direction when the shaft is turned anti-clockwise.

A cable drum of chain sprocket 9 is attached to the outer sprocket 5 assembly so that the mechanism may be used in conjunction with a chain or a cable.

The chain or cable can be attached to a carrier bar which locates on the rim or disc of a spare wheel for a lorry of other vehicle when the wheel is lying horizontally on the ground. If the spindle 2 is rotated, the spare wheel will be safely and easily raised to a height where it comes in contact with a spare wheel carrier bracket into which has been installed the gear box casing 1 and its mechanism.

If the spindle 2 is rotated in the opposite direction the wheel will be lowered to the ground safely and easily.

The gear reduction of the differential drive may be 1 7 to 1, or may be increased or decreased by employing a larger or smaller differential to occur between the number of teeth on the inner and outer sprocket assemblies.

The gear has been described as applied to the lifting and lowering of a spare wheel for a lorry or other vehicles but it may also be employed for tensioning the side curtains of commercial vehicles and for other purposes.

The gear is rotated by a cranked handle engaging the end 11 of the shaft 2.

1. A differential gear for raising and lowering articles and other purposes and particularly applicable for raising and lowering spare wheels of motor vehicles comprising a drive spindle, an eccentric or cam mounted on the spindle to rotate therewith, an inner sprocket wheel mounted on the cam or eccentric, an outer sprocket wheel loosely mounted on the spindle, a slide mounted on the inner sprocket in a recess in a slide retaining plate capable of a longitudinal movement and preventing the slide from rotation, the inner sprocket moving one or more teeth over the outer sprocket at each revolution of the shaft and an output drum or sprocket integral with the outer sprocket to provide a non-reversible reduction drive.

2. A differential gear as in claim 1, in which the gear is manually operated by a handle engaging one end of the eccentric or cam shaft.

3. A differential gear substantially as described with reference to the accompanying drawings.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in differential gears This invention relates to improvements in nonreversible differential gears particularly application for motor vehicles for raising and lowering spare wheels on lorries and other purposes. According to the invention the differential gear comprises a drive spindle, an eccentric or cam mounted on the spindle to rotate therewith, an inner sprocket wheel mounted on the cam or eccentric, an outer sprocket wheel loosely mounted on the spindle, a slide mounted on the inner sprocket in a recess in a slide retaining plate capable of a longitudinal movement and preventing the slide from rotation, the inner sprocket moving one or more teeth over the outer sprocket at each revolution of the shaft and an output drum of sprocket integral with the outer sprocket to provide a non-reversible reduction drive. The invention will be described with reference to the accompanying drawings:- Fig. 1 is a side elevation of the gear; Fig. 2 is a vertical section on line 2-3 Fig. 1; Fig. 3 is a section on line 3-3 Fig. 2; Fig. 4 is an exploded perspective view of the working parts with the casing omitted. The differential gears are assembled in a casing or gear box 1 with an eccentric input spindle 2 journaled therein. A cam or eccentric 3 is mounted on the spindle with an inner sprocket 4 mounted on the cam forming an inner sprocker assembly. An outer sprocket 5 having internal teeth, is loosely mounted on the spindle and is integral with an output sprocket assembly. These two subassemblies i.e., an inner sprocket assembly and outer sprocket assembly are arranged so that they are constantly in mesh with each other due to the cam throw, when the shaft is rotated. A slide 6 which is part of the inner sprocket assembly is located in a slide retaining plate 7 and is allowed to move in a slot 8 in the retaining plate 7, an amount which represents the maximum lateral movement of the cam 3. The slide retaining plate 7 is free to move up and down a distance which represents the maximum vertical movement of the cam 3. Having therefore accommodated the total cam movement it is possible to rotate the cam spindle 2. The slide retaining plate 7 is not allowed to rotate and therefore because the slide of the inner sprocket sliding plate 6 is located in the slot 8 in the retaining plate 7 the inner sprocket 4 assembly also cannot rotate, but instead drive the outer sprocket 5 assembly in a clockwise direction when the cam spindle 2 is rotated clockwise and in the opposite direction when the shaft is turned anti-clockwise. A cable drum of chain sprocket 9 is attached to the outer sprocket 5 assembly so that the mechanism may be used in conjunction with a chain or a cable. The chain or cable can be attached to a carrier bar which locates on the rim or disc of a spare wheel for a lorry of other vehicle when the wheel is lying horizontally on the ground. If the spindle 2 is rotated, the spare wheel will be safely and easily raised to a height where it comes in contact with a spare wheel carrier bracket into which has been installed the gear box casing 1 and its mechanism. If the spindle 2 is rotated in the opposite direction the wheel will be lowered to the ground safely and easily. The gear reduction of the differential drive may be 1 7 to 1, or may be increased or decreased by employing a larger or smaller differential to occur between the number of teeth on the inner and outer sprocket assemblies. The gear has been described as applied to the lifting and lowering of a spare wheel for a lorry or other vehicles but it may also be employed for tensioning the side curtains of commercial vehicles and for other purposes. The gear is rotated by a cranked handle engaging the end 11 of the shaft 2. CLAIMS

1. A differential gear for raising and lowering articles and other purposes and particularly applicable for raising and lowering spare wheels of motor vehicles comprising a drive spindle, an eccentric or cam mounted on the spindle to rotate therewith, an inner sprocket wheel mounted on the cam or eccentric, an outer sprocket wheel loosely mounted on the spindle, a slide mounted on the inner sprocket in a recess in a slide retaining plate capable of a longitudinal movement and preventing the slide from rotation, the inner sprocket moving one or more teeth over the outer sprocket at each revolution of the shaft and an output drum or sprocket integral with the outer sprocket to provide a non-reversible reduction drive.

2. A differential gear as in claim 1, in which the gear is manually operated by a handle engaging one end of the eccentric or cam shaft.

3. A differential gear substantially as described with reference to the accompanying drawings.