Mechanical coupling devices
A mechanical coupling for rotary devices, whereby a wind vane or other rotary tool, can be replaced without the use of a tool. In a preferred embodiment, the invention provides a coupling arrangement for a rotary device and a spindle supported for rotation, the coupling being enabled by a resilient body which acts upon a spheroidal locking member such as a ball bearing. In particular, the present invention provides a coupling arrangement for a wind vane or an anemometer rotating body comprising impeller cups, which impeller cups and rotating body are required for removable fitment, without the use of tools.
1. A rotational and axial coupling arrangement between first and second elements, the elements being arranged for rotation about an axis, the first element comprising an elongate shaft, having a coupling portion arranged about an axial section of the shaft and said second element comprising a body having a bore defined therein, with a coupling portion about an axial section of the bore;
said elements being coupled by way of a spheroidal member, the arrangement further comprising a resilient element operable to provide an axial force of separation when the coupling portions are axially aligned:
wherein the coupling portion associated with one of the first and second elements comprises a surface defining two opposing linear ridges operable to provide first and second point contact points for abutment with the spheroidal coupling member in a coupling mode;
wherein the coupling portion associated with the other of the first and second elements comprises a chamber operable to provide three point contact surfaces for abutment with the spheroidal coupling member in a coupling mode, the chamber being operable to retain the locking member in a non-coupling mode;
the arrangement being such that, in a coupling mode, the spheroidal member is contacted by the respective contact points, the resilient forces causing forces from the respective contact points to act through the spherical member, preventing separation of the first and second elements, the contact surfaces thereby ensuring defined rotational and axial alignment between the first and second elements.
2. The axial coupling according to claim 1 , wherein the spheroidal member is a sphere.
3. The axial coupling according to claim 1 , wherein the first and second contact points of the coupling member comprising two opposing linear ridges lie on the same curve and the curve corresponds with the diameter of the spheroidal element, such the two contact points comprise one elongate curve contact portion.
4. The axial coupling according to claim 1 , wherein the coupling portion with the chamber is provided with an elongate aperture, which aperture has an axial width less than the smallest diameter of spheroidal member.
5. The axial coupling according to claim 1 , wherein the coupling portion with the chamber is associated with the second element.
6. The axial coupling according to claim 1 , wherein the coupling portion operable to provide two point contact surfaces comprises a depression in the surface of the first or second element with a curved edge, inclined to said axis of rotation, said curved edge providing said two linear surfaces to provide two contact points with respect to the spheroidal member.
7. The axial coupling according to claim 1 , wherein the coupling portion operable to provide two point contact surfaces comprises a depression in the surface of the of said first or second element with a “V” shape perimeter, inclined to said axis of rotation, said “V” perimeter providing said two point contact surfaces with respect to the spheroidal member.
8. The axial coupling according to claim 1 , wherein the coupling portion operable to provide two point contact surfaces comprises a depression in the surface of the first or second element with a “V” shape perimeter, inclined to said axis of rotation, said “V” perimeter providing said two point contact surfaces with respect to the spheroidal member and wherein the “V” perimeter has arms of equal length and an axis midway therebetween is arranged such that said axis of the “V” lies in a plane which passes through said axis of rotation.
9. The axial coupling arrangement according to claim 1 , wherein the resilient element comprises one of a helical spring, resilient plastics or rubber/elastomer compound.
10. The axial coupling arrangement according to claim 1 , the first and second contact points of the first coupling member lie on the same curve and the curve corresponds with the diameter of the spheroidal element, such the two contact points comprise one elongate curve contact portion.
11. The axial coupling arrangement according to claim 1 , wherein there are two or more coupling arrangements arranged symmetrically about a shaft and bore arrangement.
12. A rotary component arrangement comprising an axial coupling arrangement in accordance with claim 1 .
13. A wind vane coupling arrangement comprising an axial coupling arrangement in accordance with claim 1 .