GB2322686A

GB2322686A - Drive coupling and apparatus including such a coupling

Info

Publication number: GB2322686A
Application number: GB9704019A
Authority: GB
Inventors: Jocelyn David Catford
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-02-26
Filing date: 1997-02-26
Publication date: 1998-09-02
Anticipated expiration: 2017-02-26
Also published as: GB9704019D0; GB2322686B

Abstract

In a drive coupling an inner component 13 has a part spherical outer surface 16 and an outer component 20 has a part spherical inner surface which is a close sliding fit over part of the outer surface of the inner component, a pair of ball bearings 24 each being located in a respective recess in one of the surfaces and engaging in a groove 17 of semi-circular cross-section in the other surface. The grooves extend in a common plane through a rotational axis of the associated component and the ball bearings 24 are located at opposite ends of a diameter in said plane. Rotation of the inner component about its drive axis will cause the outer component to rotate about an axis which may be at a variable angle relative to the drive axis, since the outer component is free to move through a limited angle in said plane by travel of the ball bearings along the groove. The ball bearings may be replaced by members attached to one component movable along grooves in the other component. The coupling may be incorporated in a foldable golf trolley having an electric motor/drive assembly (41, Figs 4,5).

Description

DRIVE COUPLING & APPARATUS INCLUDING SUCH COUPLING This invention relates to a drive coupling for transmitting rotational movement from a drive member to a driven member and to a device, particularly but not essentially a golf trolley, incorporating several such couplings.

An object of the invention is to provide a coupling in which a drive member will transmit rotational drive about an axis to a driven member but the driven member has limited freedom to rotate about an axis or axes normal to the drive axis.

In one aspect the invention provides a drive coupling comprising an inner component having a part spherical outer surface, an outer component having a part spherical inner surface which is secured as a close sliding fit over part of the outer surface of the inner component, a pair of ball bearings each located in a respective semi-circular recess in one of the surfaces and engaging in a similar semi-circular sectioned groove in the other of the surfaces, the grooves extending in a first common plane through a rotational axis of the associated component and the ball bearings preferably being located at opposite ends of a diameter in said plane.

With such an arrangement rotation of the inner component about its rotational drive axis will cause the outer component to rotate about an axis which is at a variable angle relative to the drive axis, since the outer component is free to move through a limited angle in said plane by travel of the ball bearings along the grooves, and by rotation about the diameter by rotation of the ball bearings in the grooves and recesses.

The coupling can thus transmit rotational drive about a drive axis as rotation about another axis the relative angle of which is variable through two degrees of freedom.

Preferably the allowable relative rotation extends through at least 45" and preferably substantially 90".

Preferably two grooves extend through 90" on opposite sides of one component, with advantage the inner component.

Preferably the inner component is a sphere attached to a drive shaft and the outer component has an inner surface which is of greater area than a hemisphere and is formed in two parts secured together around the inner component.

If only one degree of freedom is required the ball bearings might be replaced by detents attached to one component and movable along grooves in the other components.

Such a coupling may be incorporated in many different devices but in one aspect is particularly applied to a golf trolley. Thus in another aspect the invention provides a golf trolley having a frame on which is mounted a motor/gearbox drive assembly having an output drive rotatable about a substantially horizontal axis, a pair of wheels each rotatable about a substantially horizontal axis, each wheel being connected to the drive assembly by a respective drive shaft and couplings so as to be rotatable by the drive assembly, the wheel axis being in a different horizontal plane from the drive assembly axis in use such that the drive shafts extend downwardly and outwardly from the drive assembly to the wheels, the couplings being arranged to transmit the rotational force from the drive assembly to the wheels along the drive shafts while permitting limited relative rotation between the drive shafts and the drive assembly and wheels about axes normal to the axes of the drive shafts. This allows the trolley to be moved to a folded configuration in which the wheels are adjacent one another in a substantially common plane with the drive assembly.

One embodiment of coupling and golf trolley incorporating several such couplings will now described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a sectional view through a coupling in one position, Figure 2 is a sectional view through the coupling of Figure 1 in a different position, Figure 3 is a view of the coupling from the drive end, Figure 4 is a diagrammatic side view of a golf trolley in assembled position incorporating couplings according to Figures 1 to 3, Figure 5 is a diagrammatic front view of the wheels, drive assembly and couplings of the trolley of Figure 4, and Figure 6 shows the trolley in a folded condition.

A drive coupling 12 comprises an inner component in the form of a sphere 13 attached to a drive shaft 14 rotatable about its axis 15. The sphere has an outer surface 16 in which is formed two semi-circular sectioned grooves 17, each in the plane of the axis 15 and each extending through slightly more than 90" on opposite sides of the axis.

An outer component 20 has an inner part spherical surface 21 having an axis of symmetry 22 and extending over an area greater than a hemisphere and which is a close sliding fit over the surface 16. The inner surface 21 is formed with two recesses of semi-circular shape corresponding to the semi-circular section of the grooves 17 and located at the ends of a diameter in the plane of the grooves. Two ball bearings 24 are a close rolling/sliding fit in the recesses and grooves. The outer component 20 is formed in two parts 25, 26; part 25 being hemispherical and part 26 being annular and the two parts being secured together by fixing members in the form of four screws 27 so that the coupling components can be assembled together.

As seen in Figure 2 the inner and outer components can be rotated relative to one another through 90" about an axis 30 normal to the axis 15 with the ball bearings travelling along the grooves 17. The components can also be rotated relative to one another about an axis 31 normal to axis 15 and extending through the ball bearings, by the ball bearings rotating in the recesses and grooves. However, rotation of the drive shaft 14 and inner component 13 about the axis 15 will be transmitted to the outer component causing it to rotate about its axis 22 whatever the relative angles of one component to the other.

In an alternative the outer component may be the drive member and the inner component the driven member. The device could also be modified to incorporate one or two further similar grooves, bearings and recesses in a plane normal to the plane of Figure 1.

One device for using such a coupling comprises a foldable golf trolley 35 as seen in Figures 4 to 6 for supporting a golf bag 34. The trolley comprises a frame 36 having a free wheeling ground supported wheel 37 at its lower end and a foldable arm 38 with a handle 40 at its upper end.

Intermediate its length the frame 36 mounts an electric motor/gear box drive assembly 41. Drive assembly 41 has a drive output from each side arranged in use to provide rotation about a substantially horizontal axis 43. A pair of ground engaging wheels 44 are connected to the drive assembly 41 by respective drive shafts 45 each having a coupling 46, similar to the coupling 12, at each end. Each wheel is connected to the coupling through a free wheeling device. In use the drive shafts extend outwardly and downwardly from the drive assembly to the wheels at angles of substantially 45" to the horizontal with the wheels rotatable about substantially horizontal axes 47 and 48 below the axis 43.

By using the couplings such as couplings 12 as shown, the rotation of the output drive of the drive assembly about axis 43 is transmitted to the drive shafts as rotation about their respective axes and that rotation is transmitted to the wheels as rotation about the axes 47 and 48. However, the trolley parts can be relatively rotated to bring the wheels adjacent one another, substantially in the plane of the drive assembly and frame, in the folded condition of the trolley shown in Figure 6.

Claims

1. A drive coupling comprising an inner component having a part spherical outer surface, an outer component having a part spherical inner surface which is secured as a close sliding fit over part of the outer surface of the inner component, a pair of ball bearings each located in a respective semi-circular recess in one of the surfaces and engaging in a similar semi-circular sectioned groove in the other of the surfaces, the grooves extending in a first common plane through a rotational axis of the associated component.

2. A coupling according to Claim 1 in which the ball bearings are located at opposite ends of a diameter in said first plane.

3. A coupling according to Claim 1 or Claim 2 in which the grooves extend through at least 45 degrees of arc.

4. A coupling according to Claim 1 or Claim 2 in which the grooves extend through substantially 90 degrees of arc.

5. A coupling according to any of Claims 1 to 4 in which there are two grooves which extend on opposite sides of the inner component.

6. A coupling according to any of Claims 1 to 5 in which the inner component is a sphere attached to a drive shaft and the outer component has an inner surface which is of greater area than a hemisphere and is formed in two parts secured together around the inner component.

7. A drive coupling substantially as described herein with reference to or as illustrated in Figures 1 to 3 of the accompanying drawings.

8. A golf trolley having a drive assembly and driven wheels which in use extend in different horizontal planes from one another and are connected by drive shafts and incorporating couplings according to any of claims 1 to 7 between the drive shafts and drive assembly and wheels.

9. A golf trolley having a frame on which is mounted a drive assembly having an output drive rotatable about a substantially horizontal axis, a pair of wheels each rotatable about a substantially horizontal axis, each wheel being connected to the drive assembly by a respective drive shaft and couplings so as to be rotatable by the drive assembly, the wheel axes being in a different horizontal plane from the drive assembly axis in use, such that the drive shafts extend downwardly and outwardly from the drive assembly to the wheels, the couplings being arranged to transmit the rotational force from the drive assembly to the wheels along the drive shafts while permitting the trolley when not in use to be moved to a folded configuration in which the wheels are adjacent one another.

10. A golf trolley substantially as described herein with reference to or as illustrated in Figures 4 to 6 of the accompanying drawings.