GB2215006A - Drive chain - Google Patents

Abstract

A drive chain for use in a chain and sprocket drive comprises a series of similar links (1, 2, 3, 4) which are pivotally interconnected so that the chain is flexible in each of two mutually perpendicular directions. Each link (1, 2, 3, 4) includes a spindle (6) and a U-shaped body (7). The ends of the spindle (6) form a pair of stubs each including a roller (12, 13). The pair of stubs on any one link (1, 2, 3, 4) is perpendicular to the pair of stubs on an adjacent link, whereby alternative pairs of the stubs are engageable with a pair of sprocket wheels (16, 17) arranged on a common axis of rotation parallel to the axis of those stubs and spaced such that the non-engaging pairs of stubs can pass between the sprocket wheels (16, 17). <IMAGE>

Description

DRIVE MEMBER The present invention relates to a drive member, for example a drive chain, of the type which is flexible in two perpendicular directions.

It is an object of the present invention to provide a drive member of this type, which is suitable for engagement with twin sprocket wheels consisting of two spaced-apart sprocket wheels having a common axis of rotation.

According to a first aspect of the invention, there is provided a drive member for use with pairs of sprocket wheels arranged spaced side by side on a common axis of rotation said drive member comprising a spine capable of flexing in each of two mutually perpendicular directions and carrying pairs of stubs, the two stubs of a pair respectively projecting from opposite sides of the spine and successive pairs of stubs being perpendicular to each other.

According to a second aspect of the invention, there is provided a drive chain for use in a chain and sprocket drive comprising a series of similar links which are pivotally interconnected so hat the chain is capable of flexing in each of two mutually perpendicular directions, wherein each link of said series includes a pair of stubs, the two stubs of a pair respectively projecting from opposite sides of the link, the pair of stubs on any one link being perpendicular to the pair of stubs on an adjacent link, whereby alternate pairs of said stubs are able to engage with a pair of sprocket wheels arranged on a common axis of rotation parallel to the axis of those stubs and spaced such that the non-engaging pairs of stubs can pass between the sprocket wheels.

According to a third aspect of the invention, there is provided a chain link comprising a body portion provided with a pair of stubs, the two stubs of the pair respectively projecting from opposite sides of the body portion, a first bearing surface provided towards one end of said body portion, and a second bearing surface which is provided towards the other end of said body portion and is adapted to engage with the first bearing surface of an adjoining link when plural links are interconnected to form a chain.

Preferably the stubs are of cylindrical shape.

They may form the opposite end regions of a spindle whose central region provides a first bearing surface.

If desired the stubs may include rollers. These may be rotatably mounted on opposite ends of the spindle where this is provided.

The links of the chain advantageously comprise a U-shaped body having a spindle passing through the two arms of the U adjacent their free ends so that the opposite ends of the spindle, which may support rollers, form the stubs and the central region of the spindle between the two arms of the U forms a first bearing surface. The curved inner surface of the U forms a second bearing surface. When plural such links are interconnected, the second bearing surface of one link is engaged by the first bearing surface, e.g. the central region of the spindle, of an adjoining link.

The components of the drive may be made from a metal such as steel, or alternatively from a plastics material.

A drive chain, in accordance with the invention, can be used in conjunction with twin sprocket wheels having known shaped sprockets, and thereby avoids the necessity of providing sprockets which are specially shaped to engage within apertures provided along the length of the chain, as is necessary with prior proposals of chain drive which are flexible in two perpendicular directions.

The invention will now be further described, by way of example with reference to the accompanying drawings, in which: Figure 1 shows a partial cross-sectional view of a drive chain, according to one embodiment of the invention, in which the drive chain is engaged with a twin sprocket wheel, Figure 2 shows a cross-sectional view along the line A-A of Figure 1, in the direction of the arrows, Figure 3 shows a side view of a single link of the drive chain shown in Figures 1 and 2, Figure 4 shows a plan view of a single link shown in Figure 3, and Figures 5a to 5e show schematically various drive arrangements which can be achieved with a drive chain according to the present invention.

Referring to the drawings, Figures 1 and 2 illustrate four complete links 1 to 4 connected to form part of a drive chain, which is engaged with twin sprocket wheels shown generally at 5. The links are all identically constructed and the construction of a single link is illustrated in Figures 3 and 4. Each link is made, for example, of steel and consists of a spindle 6 and a U-shaped body 7. Each arm 8,9 of the U-shaped body is formed with an aperture 10 through which passes the spindle 6, the central portion 6a of the spindle forming a first bearing surface. The inner curved portion of the U-shaped body forms a second bearing surface 11.

The two ends of the spindle form a pair of stubs, each including a roller 12,13, which can rotate on the spindle.

As shown in figure 1, link 2 for example, is connected to link 1 by the spindle 6 of link 2 passing through between the arms 8,9 of the U-shaped body of link 2 and through the curved portion of the U-shaped body of link 1, such that the bearing surface 6a of link 2 can engage with the bearing surface 11 of link 1.

As shown more clearly in Figure 2, the twin sprocket wheel 5 consists of two parallel, spaced-apart identical sprocket wheels 16,17 which have respective aligned sets of teeth 14 and a common axis of rotation. A spacer 18 retains the two sprocket wheels 16,17 at the desired spacing.

As can be seen, each of the two rollers 12,13 of the stubs of alternate links, for example links 1 and 3, engages between two successive teeth 14 of one of the sprocket wheels, whilst the rollers of the stubs of the other alternate links, for example links 2 and 4, extend perpendicular with respect to the stubs of the first mentioned links and are located in the space 15 between the two sprocket wheels 16,17.

The chain can be formed from any number of identical links, with adjacent links being orientated at right angles to each other along the length of the chain, as shown. The spindle of each link can pivot about its longitudinal axis so that adjacent links have respective pivotal axes located perpendicular to each other.

In this way, the chain is made flexible in two perpendicular directions and can be used to drive angled sprocket wheel drive arrangements, as shown schematically in Figures 5a to 5e. Figures 5a to Sc each show two twin sprocket wheel assemblies 20,21 positioned so that their respective horizontal rotational axes are located at different angles with respect to each other. An endless drive chain 22, constructed in accordance with an embodiment of the present invention, engages around both twin sprocket wheels and is guided through the angle of each arrangement by two rotary guide members 23,24 having coincident vertical rotational axes. Each rotary guide member is circular in shape and is formed with two annular outer surfaces, which are spaced apart by an annular groove. In this way, the rollers of alternate links of the drive cain 22, which extend in a direction parallel to the rotational axis of the guide member, roll around the annular surfaces, whilst the rollers of intermediate links, which extend in a generally radial direction of the guide member, are accommodated in the groove.

Figure 5d shows two twin sprocket wheel assemblies 25,26 having coincident vertical rotational axes and two further twin sprocket wheel assemblies 27,28 having coincident horizontal rotational axes. An end less drive chain 29, constructed in accordance with an embodiment of the present invention, engages around all four twin sprocket wheels, so that the rotate in. the directions shown by the arrows. Figure 5e illustrates a similar arrangement to that shown in Figure 5d, except that the vertical rotational axes of twin sprocket wheels 30,31 are staggered relative to each other, as are also the horizontal rotational axes of twin sprocket wheels 32,33.

The rive chain of the present invention, may be used to replace expensive bevel gear arrangements in machinery or drive systems in which the power transmitting parts are angled with respect to eac other.

More specifically, the drive chain may be employed in power transmitting facilities of vehicles of, for example, the agricultural type; in milling machine arrangements; in the running gears of prcduction lines; in precision equipment requiring link transmission rather than drive belts; and in multi-wheel vehicle transmissions, as well as many other types of machinery.

Whilst particular embodiments of the present invention have been described, various modif-cations will be envisaged without departure from the scope of the invention.

Claims (16)

1. A device comprising a drive member for use with pairs of sprocket wheels arranged spaced side by side on a common axis of rotation, said drive member comprising a spine capable of flexing in each of two mutually perpendicular directions and carrying pairs of stubs, the two stubs of a pair respectively projecting from opposite sides of the spine and successive pairs of stubs being perpendicular to each other.

2. A device comprising a drive chain for use in a chain and sprocket drive, said drive chain comprising a series of similar links which are pivotally interconnected so that the chain is capable of flexing in each of two mutually perpendicular directions, wherein each link of said series includes a pair of stubs, the two stubs of a pair respectively projecting from opposite sides of the link, the pair of stubs on any one link being perpendicular to the pair of stubs on an adjacent link, whereby alternate pairs of said stubs are able to engage with a pair of sprocket wheels arranged on a common axis of rotation parallel to the axis of those stubs and spaced such that the non-engaging pairs of stubs can pass between the sprocket wheels.

3. A device comprising a chain link comprising a body portion provided with a pair of stubs, the two stubs of the pair respectively projecting from opposite sides of the body portion, a first bearing surface provided towards one end of said body portion, and a second bearing surface which is provided towards the other end of said body portion and is adapted to engage with the first bearing surface of an adjoining link when plural links are interconnected to form a chain.

4. A device as claimed in claim 1,2 or 3, wherein the stubs are of cylindrical shape.

5. A device as claimed in any preceding claim, wherein the stubs form the opposite end regions of a spindle whose central region provides a first bearing surface.

6. A device as claimed in any preceding claim, wherein the stubs include rollers.

7. A device as claimed in claim 5 and 6, wherein the rollers are rotatably mounted on opposite ends of the spindle.

8. A device as claimed in any one of claims 2 to 7, wherein each link of te chain comprises a U-shaped body having a spindle passing through the two arms of the U adjacent their free ends so that the opposite ends of the spindle, which may support rollers, form the stubs and the central region of the spindle between the two arms of the U forms a first bearing surface.

9. A device as claimed in claim 8, wherein the curved inner surface of the U forms a second bearing surface, such that when plural such links are interconnected, the second bearing surface of one link is engaged by the first bearing surface of an adjoining link.

10. A device as claimed in any preceding claim, wherein the components of the device are made from a metal such as steel.

11. A device as claimed in any one of claims 1 to 10, wherein the components of said device are made from a plastics material.

12. A drive member substantially as herein described with reference to the accompanying drawings.

13. A drive chain substantially as herein described with reference to the accompanying drawings.

14. A chain link substantially as herein described with reference to the accompanying drawings.

15. An angled sprocket wheel drive arrangement comprising at least two twin sprocket wheel assemblies positioned such that the respective rotational axes of said wheel assemblies are oriented at an angle with respect to each other, and a device as claimed in any preceding claim in driving engagement with the wheel assemblies.

16. An angled sprocket wheel drive arrangement as claimed in claim 15, and including a plurality of rotary guide members with which said device also engages.

1 7. An angled sprocket wheel drive arrangement substantially as herein described with reference to the accompanying drawings.