ROLLER CHAIN PLATES

FIELD OF INVENTION

The present invention relates to roller chain plates.

BACKGROUND OF THE INVENTION

Existing means for transmitting mechanical power include a roller chain comprising a number of repeating units linked together in a form of loop. The major components of each unit are a plurality of metal plates. The plates may be generally classified as inner and outer plates. To link and fasten the plates to form a roller chain, the pins are used to join each pair of outer plates; while the bushes are used to join each pair of inner plates. A normal roller chain is configured such that the pin is inserted through a pair of outer plates and a pair of inner plates through the plates’ common openings, and such that the bush generally concentrically encloses the pin. During the intended use, the roller chain is coupled and engaged with a set of sprockets. Roller chains are moving parts of heavy machineries or vehicles, and so is exposed to a high tension and wear; they have a substantially shorter lifecycle expectancy than the sprockets with which they are coupled.

A roller chain’s major cause of wear is the pin and the bush’s pulling and scraping against each other. As the wear develops, the void between the two components grows wider and the roller chain consequently elongates. The process would continue until the roller chain breaks, or becomes intolerably incompatible with the sprockets.

A conventional way of maintaining a roller chain against such wearing is lubrication, e.g. by grease or the like. US 2,185,702 suggests that a greater proportion of wearing occurs in the inner surfaces of the roller chain, i.e. at a contact point between the pin and the bush— the location that is almost inaccessible by the lubricant applied from the exterior. The same publication accordingly discloses an improvement to then-previous roller chains by configuring the roller chain so as to facilitate such lubricant’s access to the inner surface. The durability of roller chains, however, may be further improved by other means.

An object of the present application is to provide a new configuration of roller chain which improves its durability. SUMMARY OF THE INVENTION

It is an objective of the present invention to provide roller chain plates which improves durability.

In order to achieve the above objective, an embodiment of the present invention provides roller chain plates comprising an inner plate and an outer plate. The inner plate has an inner plate inner side, an inner plate outer side being opposite to the inner plate inner side, two inner ends that each having a bush hole, and an inner connecting portion connecting two inner ends. The outer plate has an outer plate inner side, an outer plate outer side being opposite to the second inside surface, two outer ends that each having a pin hole, an outer connecting portion connecting two outer ends.

The inner plate has a boss portion disposing on the periphery of each bush hole on the inner plate outer side, and the outer plate has an annular protruding portion disposing around each pin hole on the outer plate inner side, which comes into contact and engagement with the chamfer when the roller chain is assembled.

According to the embodiment of the present invention, with this engagement, it is possible that the load on the bush is distributed to both the inner plate and the outer plate. Comparing with the conventional roller chain that the load on the bush is distributed to the inner plate only, the wear of each part of this embodiment can be decreased because the load distribution is improved as the outer plate and the inner plate are together formed as a load- bearing part of the bush. As a result, the durability of the roller chain is increased.

In addition, when the annular protruding portion is engaged with the boss portion when the roller chain is assembled, the position of the bush is fixed due to the position of the inner plate is fixed. As a result, an elongation rate of the chain is decreased.

Other objects, advantages, and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Referring to the drawings which form a part of this disclosure:

FIG.l is an exploded view of a roller chain according to an embodiment of the present invention;

FIG.2a is a front view of an inner plate according to the embodiment of the present invention; FIG.2b is a back view of the inner plate according to the embodiment of the present invention; FIG.2c is a perspective view of the inner plate according to the embodiment of the present invention;

FIG.2d is a cross sectional view of the inner plate according to the embodiment of the present invention along section line A- A of FIG.2c;

FIG.3 a is a front view of an outer plate according to the embodiment of the present invention; FIG.3b is a back view of the outer plate according to the embodiment of the present invention; FIG.3c is a perspective view of the outer plate according to the embodiment of the present invention;

FIG.3d is a cross sectional view of the outer plate according to the embodiment of the present invention along section line B-B of FIG.3c;

FIG.4 is a cross sectional view of the roller chain according to the embodiment of the present invention.

Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.

DETAILED DESCTIPTION OF EMBODIMENTS OF THE INVENTION

Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

As used herein to describe the parts of the roller chain plates, specifically, an inner plate 110 and an outer plate 210, the following directional terms "inside", "outside", "inner", "outer", as well as any other similar directional terms refer to those directions relative to the roller chain plates in an assembly position. Such directional terms used in conjunction with the following description of the drawings should not be construed to limit the scope of the invention in any manner not explicitly set forth.

The present invention will be described in detail hereinafter with reference to the accompanying drawings. FIG. 1 illustrated a roller chain 1 according to an embodiment of the present invention. Referring to FIG. 1, the roller chain 1 basically includes a plurality of a pair of inner plates 110, 110 and a plurality of a pair of outer plates 210, 210. Each pair of the inner plates 110, 110 connects together by a pair of pins 40, 40 to form an inner link 10 and each pair of the outer plates 210, 210 connects together by a pair of bushes 30, 30 to form an outer link 20. Each pin 40 is slidably positioned inside each corresponding bush 30 so that the outer link 20 is alternately flexibly connected to the inner link 10. Preferably, the roller chain 1 has a roller 50 which is rotatably positioned outside each bush 30.

FIG. 1 shows the shape of the pin 40 which is a solid cylinder and the shape of the bush 30 and the roller 50 which are a hollow cylinder. The bush 30, the pin 40, and the roller 50 are well known structures. Therefore, the detail will not be discussed herein, except as required to explain the configuration of the roller chain 1. Moreover, the shape of the bush 30, the pin 40, and the roller 50 can vary as needed, such as the pin 40 can be hollow cylinder if needed.

FIGs. 2a-2d shows the inner plate 110 of the roller chain 1. The inner plate 110 has an inner plate inner side 120a, an inner plate outer side 120b which is opposite to the inner plate inner side 120a, and an inner plate outer edge 130 which is disposed between the inner plate inner side 120a and the inner plate outer side 120b.

Each inner plate 110 includes two inner ends 140, 140 and an inner connecting portion 160 which connects two inner ends 140, 140. Preferably, the contour of each inner end 140 is a curved shape. More preferably, the contour of each inner end 140 is a circular shape. Preferably, the contour of the inner connecting portion 160 is curved towards the inside of the inner plate 110. However, the contour of the inner connecting portion 160 is not limited to the curved shape. For example, the contour of the inner connecting portion 160 can be straight if needed.

Each inner end 140 has a bush hole 150 defining by an inner plate cylindrical wall 155 for receiving one end of the bush 30. The diameter of each bush 30 is slightly larger than the diameter of the bush hole 150. In such manner, the end of the bush 30 can be press-fitted into the bush hole 150.

For this embodiment, a boss portion 170 is formed on the inner plate outer side 120b by projecting axially from the inner plate outer side 120b. The boss portion 170 is disposed on the periphery of the each bush hole 150 to extend the height of the inner plate cylindrical wall 155. The boss portion comprises a boss portion inside wall 172 and a boss portion outside wall 174. The shape of the boss portion 170 is preferably a hollow cylinder. However, the shape of the boss portion 170 is not limited.

With this arrangement, when the height of the inner plate cylindrical wall 155 is increased, the strength of the inner plate 110 is increased. Moreover, this arrangement leads to an increasing in the contact surface area between the bush 30 and the inner plate 110 which the contact stress on the bush 30 can be decreased as a result. Therefore, the thickness of the inner plate 110, excluding the boss portion 170, can be reduced for the desired load when compared with the conventional inner plate 110, and a cost reduction can be achieved. The boss portion 170 is disposed on the periphery of each bush hole 150. The boss portion 170 engages with an annular protruding portion 270 of the outer plate 210 when the roller chain 1 is assembled, which will be described in detail later.

The inner plate 110 is preferably formed as a one-piece from a rigid material such as metallic material. Preferably, the inner plate 110 is manufactured by the fine blanking process.

The inner plate 110 preferably has the same minimum thickness between the inner plate inner side 120a and the inner plate outer side 120b, excluding the boss portion 170. The inner plate outer side 120b, excluding the boss portion 170, and the inner plate inner side 120a are preferably smooth and flat.

FIGs. 3a-3d shows the outer plate 210 of the roller chain 1. The outer plate 210 has an outer plate inner side 220a, an outer plate outer side 220b which is opposite to the outer plate inner side 220a, and an outer plate outer edge 230 which is disposed between the outer plate inner side 220a and the outer plate outer side 220b.

Each outer plate 210 includes two outer ends 240, 240 and an outer connecting portion 260 which connects two outer ends 240, 240. Preferably, the contour of each outer end 240 is a curved shape. More preferably, the contour of each outer end 240 is a circular shape. Preferably, the contour of the outer connecting portion 260 are curved towards the inside of the outer plate 210. However, the contour of the outer connecting portion is not limited to the curved shape. For example, the contour of the outer connecting portion 260 can be straight if needed.

Each outer end 240 has a pin hole 250 defining by an outer plate cylindrical wall 255 for receiving one end of the pin 40. The diameter of each pin 40 is slightly larger than the diameter of the pin hole 250. In such manner, the end of the pin 40 can be press-fitted into the pin hole 250.

For this embodiment, the annular protruding portion 270 is formed on the outer plate inner side 220a by protruding axially from the outer plate inner side 220a. The annular protruding portion 270 is disposed around each pin hole 250 and shared the central axis with the pin hole 250. The annular protruding portion 270 comprises a protruding portion inside wall 272 and a protruding portion outside wall 274. The radius of the protruding portion inside wall 272 is substantially the same as the radius of the boss portion outside wall 174 so as to allow the boss portion 170 to fit into the annular protruding portion 270 to prevent the inner plate 110 and the outer plate 210 to move away from each other but allow rotational movement of both plates 110, 210 along the central axis when the roller chain 1 is assembled. Preferably, the shape of the annular protruding portion 270 is a hollow cylinder. However, the shape of the annular protruding portion 270 is not limited.

With this engagement when the roller chain 1 is assembled, it is possible that the load on the bush 30 is distributed to both the inner plate 110 and the outer plate 210. Comparing with the conventional roller chain that the load on the bush is distributed to the inner plate only, the wear of each part of this embodiment can be decreased because the load distribution is improved as the outer plate 210 and the inner plate 110 are together formed as a load-bearing part of the bush 30. As a result, the durability of the roller chain 1 is increased.

The outer plate 210 is preferably formed as a one-piece from a rigid material such as metallic material. Preferably, the outer plate 210 is manufactured by the fine blanking process. An annular recess portion 280 is formed as a consequence of pressing the outer plate 210 to form the annular protruding portion 270. Thus, the annular recess portion 280 is disposed around each pin hole 250 on the outer plate outer side 220b. The annular recess portion 280 is shared the central axis with the pin hole 250. With this arrangement, it becomes possible to increase the strength around the annular recess portion 280 due to the fine blanking process that affects the physical properties of the outer plate 210.

The outer plate 210 preferably has the same minimum thickness between the outer plate inner side 220a and the outer plate outer side 220b, excluding the annular protruding portion 270 and the annular recess portion 280. The outer plate inner side 220a excluding the annular protruding portion 270, and the outer plate outer side 220b excluding the annular recess portion 280 are preferably smooth and flat.

Referring to FIG. 4, the assembly of the roller chain 1 will now be explained. The roller chain 1 comprises at least the inner link 10 and the outer link 20.

The inner link 10 has at least a pair of inner plates 110, 110 and a pair of bushes 30, 30. The inner plate inner sides 120a of each pair of inner plates 110, 110 faces each other in each of the inner link 10 and define sprocket receiving spaces that receive the teeth of the sprocket (not shown). Two ends of each bush 30 are press-fitted into the bush hole 150 of the pair of inner plates 110, 110 placing opposite to each other.

The outer link 20 has at least the pair of outer plates 210, 210 and the pair of pins 40, 40. The outer plate 210 is arranged on the inner plate outer side 120b of the inner plate 110 so that the annular protruding portion 270 of the outer plate 210 comes into contact and engagement with the boss portion 170 of the inner plate 110 to allow the boss portion 170 to fit into the annular protruding portion 270 to prevent the inner plate 110 and the outer plate 210 to move away from each other but allow rotational movement of both plates 110, 210 along the central axis. Each pin 40 is slidably positioned inside the bush 30. Two end of each pin 40 are press-fitted into the pin hole 250 of the pair of outer plate 210 so that the outer link 20 is alternately flexibly connected to the inner link 10. Preferably, the roller chain 1 has a roller 50 which is rotatably positioned outside each bush 30.

Normally, when the roller chain operates, the outer surface of the pin and the inner surface of the bush mb against each other, leads to the wearing of contact surface between the pin and the bush. As the surface of the pin and the bush is worn, the roller chain becomes longer to the point that the adjustment of elongation is no longer possible. For this embodiment, when the annular protruding portion 270 is engaged with the boss portion 170 when the roller chain 1 is assembled, the position of the bush 30 is fixed due to the position of the inner plate 110 is fixed. As a result, an elongation rate of the chain is decreased.

While a particular embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.

List of reference:

1 roller chain

10 inner link

110 inner plate

120a inner plate inner side

120b inner plate outer side

130 inner plate outer edge

140 inner end

150 bush hole

155 inner plate cylindrical wall

160 inner connecting portion

170 boss portion

172 boss portion inside wall

174 boss portion outside wall

20 outer link

210 outer plate

220a outer plate inner side

220b outer plate outer side

230 outer plate outer edge

240 outer end pin hole outer plate cylindrical wall outer connecting portion annular protruding portion protruding portion inside wall protruding portion outside wall annular recess portion bush

pin

roller