WO2017068333A1

WO2017068333A1 - Coupling

Info

Publication number: WO2017068333A1
Application number: PCT/GB2016/053217
Authority: WO
Inventors: Simon Parker
Original assignee: Punk Couplings Limited
Priority date: 2015-10-22
Filing date: 2016-10-18
Publication date: 2017-04-27
Also published as: GB201806220D0; GB2557838A; GB2557838B; GB201518768D0

Abstract

A coupling made having a male spherical bearing surface contacting the inner periphery of a contiguous female spherical race. The male bearing surface having a central axis of rotation and a cylindrical waist formed in the surface having an axis orthogonal to the axis of the male bearing surface. The diameter of the waist is such that it will fit within the orifice of the race.

Description

COUPLING

Field of Invention

The present invention relates to a coupling and a method of assembling a coupling.

Background

WO

WO 2015/087080

A PUNK COUPLINGS LIMITED 20150618

and

WO

WO 2015/087081

A PUNK COUPLINGS LIMITED 20150618

describe couplings comprising:

one or more pairs of members, which may or may not include one or both the inner and outer members, each pair being a first member and a second annular member with a common axis and having a common first centre on the axis;
the first member having an outer convex spherical periphery;
the second annular member having an inner spherical concave periphery in which the outer convex periphery of the first annular member is received;
the outer convex periphery and the inner concave peripheries being concentric about the first centre and complementary to one another and co-acting with one another to transmit axial loads acting along the torsional axis between them;
the second member being constrained to rotate about the first member about an axis that is perpendicular to the common axis and
the said members, other than the outer member, comprise spherical segments including a common centre.

It is possible to place the first member or male member, inside the second member or female member by forming the female in two parts, placing the two parts around the male member and then welding or bolting the two halves together. However, this leaves a potential source of weakness in the second member which could lead to failure, and so it is preferred in WO2015/087080 and WO2015/087081 that the second annular member of a pair of members has a pair of diametrically opposed loading slots by which the first member of the pair of members may be inserted to be retained within the coupling.

This approach is relatively expensive to machine; the costs may not be justified for use in mass produced light duty cycle couplings.

Summary of the Invention

According to the present invention coupling comprising one or more pairs of members, which may or may not include one or both the inner and outer members, each pair being a first member and a second annular member with a common axis and having a common first centre on the axis;

the first member having an outer periphery forming a male spherical bearing;
the second annular member having an inner spherical concave periphery acting as a female race in which the outer convex periphery of the first annular member is received;
the outer convex periphery and the inner concave periphery each being concentric about the first centre and complementary to one another and co-acting with one another to transmit axial loads acting along the torsional axis between them;
the second member being constrained to rotate about the first member about an axis that is perpendicular to the common axis and
the said members, other than the outer member, comprise spherical segments including a common centre

is characterised in that the first member has a cylindrical waist about a waist axis with diameter fitting within the orifice of the second member.

Normally the axis of the waist is orthogonal to the common axis.

The advantages of the invention include easy manufacture using injection moulding or pressing operations such as powder metallurgy/sintering when using low friction materials and/or coatings. Typical uses of couplings of this kind would be low duty cycle mechanisms in clean environments such as printers/photocopies and automotive mirror, heater control mechanisms and the like.

In one embodiment, rotation of the second member with respect to the first member is constrained by one or a pair of projections from one member into one or a pair of slots in the other member, the projections and slots being orthogonal to the central axis of the first member as described in WO2015/087080

In another embodiment, rotation of the second member with respect to the first member is constrained by one or a pair of axles mounted in the pair of members, the axes of the axles being orthogonal to the central axis of the first member as described in WO2015/087081.

Brief description of drawings

Embodiments of the invention are described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1A to 1F show an example of the invention used in a coupling of the kind described in wo2015/087080, figure 1A is a orthogonal view of the coupling misaligned, figure 1B is a side vie of the coupling, figure 1C is a section of the coupling on vertical plane including axis A3 of figure 1A, figure 1D is a top view of the coupling, figure 1E is a section of the coupling on the axis A2 of figure 1A and figure 1F is a perspective view of the coupling;

Figure 2 shows an exploded view of the coupling of figures 1A to 1F;

Figure 3A to 3F show an example of the invention used in a coupling of the kind described in WO2015/087081, figure 3A is a orthogonal view of the coupling misaligned, figure 3B is a side view of the coupling, figure 3C is a section of the coupling on vertical plane including axis A3 of figure 1A, figure 3D is a top view of the coupling, figure 3E is a section of the coupling on the axis A2 of figure 3A and figure 2F is a perspective view of the coupling;

Figure 4A shows an axial view of the coupling of figures 3A to 3F, figure 4B shows a vertical section through of the coupling of figures 4A; and

Figure 5 shows an exploded view of the coupling of figures 3A to 3F and 4A and 4B.

Description of examples of the invention

In figures 1 and 2 a coupling comprises a first, inner annular member 1, annular intermediate member 2 and an annular outermost member3. Each of the

members

1, 2, 3 comprises spherical segments about the centre C. The inner annular member 1 is centred on a first axis A1, the inner annular member 1 having an outer peripheral surface S1 which is convexly spherical centred on the point C on the axis A1. The first inner annular member 1 has a central bore which in this example has a keyway 6 engaging a corresponding key on a shaft.

The intermediate annular member 2 has an inner peripheral surface S21 which is concavely spherical complementary to the outer surface S1 of the first inner member 1. In this example the inner spherical surface S21 of the intermediate member 2 forms a female race of the invention and the outer spherical surface S1 of the first inner member the male bearing surface of the invention.

Diametrically opposite elongate projections M1 and M11 extends radially of, and parallel to, the first axis A1 from the convex spherical surface S1 of the inner member 1. The radially outer surface of the projection also extends parallel to the spherical surface S1 but can also be cylindrical in nature. The projections extend into complementary slots K1 and K11 in the inner concave surface S21 of the intermediate member 2. The projections M1, M11 and slots K1 K11 constrain the first inner 1 and intermediate member 2 to be rotatable one relative to the other about the second axis A3 of rotation through and perpendicular to the first axis A1.

The intermediate member 2 has an outer periphery S22 which is convexly spherical and forms a second male surface of the invention. The outermost annular member 3 has an inner peripheral surface S31 which is concavely spherical complementary to the outer surface S22 of the intermediate member 2. The inner spherical surface S31 of the outermost member forms a second female race of the invention.

Second elongate projections M2 and M21 extend radially of, and parallel to, the first axis from the convex spherical surface S22 of the intermediate member 2. The radially outer surface of the second projections M2 and M21 also extends parallel to the spherical surface. But can also be cylindrical in nature.

The projections M2 and M21 extend into complementary, second, slots K2 and K21 in the inner concave surface of the outermost member 3. The second projection M2 and M21 and second slots K2 and K21 are perpendicular to the first projections M1, M11, and first slots K1, K11. They constrain the intermediate 2 and outermost 3 members to be rotatable one relative to the other about the third axis A2 of rotation through the centre point C, and perpendicular to both the first axis A1and second axis A3.

In this example outer member 3 has a keyway 7 to receive an internal key of a shaft to which it may be connected.

The inner member 1 is retained in the intermediate member 2 by the male bearing surface S1 constrained within female race S21, and the intermediate member 2 is retained by the male bearing surface S22 within female race S31.

In this example the projections M11 and M21 and corresponding slots K11 and K21 could be omitted but with less security in the event of failure.

The male bearing surface S1 of inner member 1 has a cylindrical waist 8 whose axis is coincident with axis A2 and orthogonal to the first axis A1. The diameter of the cylindrical waist is just less than the aperture 4 of intermediate member 2.

To assemble the inner member 1 within the intermediate member 2, inner member 1 is lined up within intermediate member 2 to be at right angles to intermediate member 2, but with projections M1 and M11 aligned with their corresponding slots K1 and K11. Inner member 1 is now rotated to bring surface S1, the male spherical bearing surface into contact with the inner periphery S21 of the intermediate member 2.

Similarly, the male bearing surface S21 of intermediate member 2 has a cylindrical waist 9 whose axis is coincident with axis A3 and orthogonal to the first axis A1. The diameter of the cylindrical waist is just less than the aperture 5 of intermediate member 3.

To assemble the intermediate member 2 within the outer member 3, intermediate member 2 is lined up within outer member 3 to be at right angles to intermediate member 3, but with projections M2 and M21 aligned with their corresponding slots K2 and K21. Intermediate member 2 is now rotated to bring surface S22 the male spherical bearing surface into contact with the inner periphery S31 of the outer member.

In figures 3 to 5 a coupling comprises an inner annular member 1 centred on a first axis, the inner annular member 1 having an outer peripheral surface S1 which is convexly spherical centred on the point C on the axis A1. The inner annular member 1 has a central keyway 6 for engaging a key on a shaft.

A first pair of diametrically opposed axles X1 and X11 extend radially of, the first axis A1 on the third axis A2 to couple the inner member 1 to the intermediate member 2. The first and second axles constrain the inner and intermediate members to rotate one relative to the other about the third axis A2. The intermediate member 2 has an outer periphery S22 which is convexly spherical. The intermediate member 2 has an outer periphery S22 which is convexly spherical and forms a second male surface of the invention. The outermost annular member 3 has an inner peripheral surface S31 which is concavely spherical complementary to the outer surface S22 of the intermediate member 2. The inner spherical surface S31 of the outermost member forms a second female race of the invention.

A second pair of diametrically opposed axles X2 and X21 extend radially of, the first axis A1 along the second axis A3 perpendicular to the third axis A2 to couple the intermediate member 2 to the outer member 3. The axles X2 and X21 constrain the intermediate 2 and outer 3 members to be rotatable one relative to the other about the second axis A3 of rotation (see Figure 1) through the centre point C, and perpendicular to the first axis A1 and perpendicular to the third axis A2. The second pair of axles allows relative rotation of the pair of members comprising intermediate and

outer members

2 and 3 independently of the pair of members comprising inner and intermediate members 1 and 2.

The male bearing surface S1 of inner member 1 has a cylindrical waist 8 is orthogonal to the first axis A1. However, to maximise the strength of inner member 1, the waist is positioned between axles X1, and X11, with its axis at 45^o to the axes A2 and A3. The diameter of the cylindrical waist is just less than the aperture 4 of intermediate member 2.

To assemble the inner member 1 within the intermediate member 2, inner member 1 is lined up within intermediate member 2 to be at right angles to intermediate member 2. Inner member 1 is now rotated to bring surface S1, the male spherical bearing surface, into contact with the inner periphery S21 of the intermediate member 2. Axles X1 and X11 are then inserted into their axle holes.

Similarly, the male bearing surface S21 of intermediate member 2 has a cylindrical waist 9 whose axis is and orthogonal to the first axis A1. However, to maximise the strength of inner member 1, the waist is positioned between axles X1, and X11, with its axis at 45^o to the axes A2 and A3. The diameter of the cylindrical waist is just less than the aperture 5 of intermediate member 3.

To assemble the intermediate member 2 within the outer member 3, intermediate member 2 is lined up within outer member 3 to be at right angles to intermediate member 3. Intermediate member 2 is now rotated to bring surface S22, the male spherical bearing surface, into contact with the inner periphery S31 of the outer member. Axles X2 and X21 are then inserted into their axle holes and held in place with an interference fit with the axle holes in outer member 3.

Claims

A coupling according to the invention comprising one or more pairs of members, which may or may not include one or both the inner and outer members, each pair being a first member and a second annular member with a common axis and having a common first centre on the axis; the first member having an outer periphery forming a male spherical bearing; the second annular member has a central orifice and an inner spherical concave periphery acting as a female race in which the outer convex periphery of the first annular member is received; the outer convex periphery and the inner concave periphery each being concentric about the first centre and complementary to one another and co-acting with one another to transmit axial loads acting along the torsional axis between them; the second member being constrained to rotate about the first member about an axis that is perpendicular to the common axis and the said members, other than the outer member, comprise spherical segments including a common centre characterised in that the first member has a cylindrical waist about a waist axis with diameter fitting within the orifice of the second member.
A coupling according to claim 1 in which the axis of cylindrical waist axis is orthogonal to the common axis.
A coupling according to claim 1 or 2 in which rotation of the second member with respect to the first member is constrained by one or a pair of projections from one member into one or a pair of slots in the other member, the projections and slots being orthogonal to the central axis of the first member.
A coupling according to claim 1 or 2 in which rotation of the second member with respect to the first member is constrained by one or a pair of axles mounted in the pair of members, the axes of the axles being orthogonal to the central axis of the first member.