CN210830324U

CN210830324U - Random chain

Info

Publication number: CN210830324U
Application number: CN201921550265.3U
Authority: CN
Inventors: 吴瑞章
Original assignee: KMC Chain Industrial Co Ltd
Current assignee: KMC Chain Industrial Co Ltd
Priority date: 2019-08-08
Filing date: 2019-09-16
Publication date: 2020-06-23
Anticipated expiration: 2029-09-16
Also published as: TWM586763U

Abstract

A random chain comprises a plurality of guide blade groups and a plurality of repeating units which are arranged in an extending way along the length direction, and a plurality of chain shafts. Each guide sheet set comprises two guide sheets which are opposite to each other at intervals in the width direction. Each repeating unit comprises two medium chain pieces and four inner chain pieces, wherein the two medium chain pieces are superposed with each other and are spaced between the guide pieces of the corresponding guide piece group. Every two pieces of the inner chain pieces are overlapped with each other along the width direction in a group and are positioned between the corresponding middle chain piece and the corresponding guide piece. The chain shaft is used for connecting the guide sheet, the middle chain sheet and the inner chain sheet in series. The medium chain piece and the inner chain piece arranged along the width direction of each repeating unit and each of the medium chain piece and the inner chain piece arranged along the length direction are randomly selected from one of a first tooth piece and a second tooth piece with different structures.

Description

Random chain

Technical Field

The utility model relates to a be used for driven chain, especially relate to a lower random chain of noise when moving.

Background

Referring to fig. 1, a conventional random chain 1 includes a plurality of links 11 repeatedly arranged in a length direction and connected to each other in series. Each link 11 has a plurality of link plates 111 stacked in a width direction, and a plurality of link shafts 112 for stringing the link plates 111 together.

There are two different styles of such a random chain 1. One of the random chains 1 is formed by randomly arranging two kinds of tooth plates with different structures, wherein the chain plates 111 arranged in each chain link 11 along the width direction are arranged. The other random chain 1 is formed by randomly arranging two types of tooth plates with different structures on the chain plate 111 which is arranged in a row along the length direction.

That is, the conventional random chain 1 has a unidirectional random design along the width direction and a unidirectional random design along the length direction. Although the conventional random chain 1 has an effect of reducing the running noise to a certain extent, the noise reduction effect still needs to be further improved because it only adopts a one-way random design.

Disclosure of Invention

The object of the present invention is to provide a random chain that overcomes at least one of the drawbacks of the prior art.

The utility model discloses random chain extends along length direction to, and defines out the width direction of crossing this length direction, and this random chain includes a plurality of guide plate groups, a plurality of repeating unit, many first chain axles, and many second chain axles, guide plate group extends along this length direction and arranges, and each guide plate group includes two relative guide plate along this width direction interval, and each guide plate is formed with along this length direction front and back spaced preceding guide plate hole and back guide plate hole, the repeating unit extends along this length direction and arranges, and each repeating unit includes two middle chain pieces that superpose each other and lie in this guide plate group that corresponds along this width direction interval between the guide plate to and four interior chain pieces, and each middle chain piece is formed with along this length direction front and back spaced preceding middle plate hole and back middle plate hole, every two piece of interior chain piece superpose each other for a set of ground along this width direction, and are located between the corresponding said middle chain sheet and the corresponding said guide sheet along the width direction, each inner chain sheet is formed with a front inner sheet hole and a back inner sheet hole spaced back and forth along the length direction, each first chain shaft is inserted into the front middle sheet hole of one of the guide sheet sets and the front middle sheet hole of the corresponding one of the repeating units and the back inner sheet hole of the adjacent other repeating unit, each second chain shaft is inserted into the back middle sheet hole of the one of the guide sheet sets and the back middle sheet hole of the one of the repeating units and the front inner sheet hole, each of the middle chain sheets and the inner chain sheets arranged along the width direction of each repeating unit is randomly selected from one of a plurality of kinds of tooth sheets with different structures, each of the middle chain sheets arranged in a row along the length direction is randomly selected from one of the tooth sheets, each of the inner chain sheets arranged in a row along the length direction, randomly selected from one of the teeth.

The random chain, each repeating unit is arranged along the width direction the medium chain piece and each of the inner chain pieces are randomly selected from one of a first tooth piece and a second tooth piece with different structures, are arranged in a line along the length direction each of the medium chain pieces are randomly selected from one of the first tooth piece and the second tooth piece, are arranged in a line along the length direction each of the inner chain pieces are randomly selected from one of the first tooth piece and the second tooth piece.

In the random chain of the present invention, each first tooth plate includes a first long side extending in the length direction, a first concave side spaced apart from the first long side and recessed toward the first long side, two first short bevel sides extending from the first long side back to the first concave side, two first arc sides protruding from the first concave side in a direction opposite to the first long side, two first long bevel sides extending from the first arc sides back to the first long side, and two first lateral arc sides connected between the first long bevel sides and the first short bevel sides, each second tooth plate includes a second long side extending in the length direction, a second concave side spaced apart from the second long side in the width direction and recessed toward the second long side, two second arc sides protruding from the second concave side in a direction opposite to the second long side, and two second long bevel sides extending from the second arc sides back to the second long side, and two second side arc edges connected between the second long oblique edge and the second long edge.

Random chain, it is individual along N of this length direction range each repeating unit in the repeating unit, it is not repeated with arbitrary other repeating unit, and N is 2 to 64 integer.

The utility model discloses random chain extends along length direction, defines out the width direction of crossing this length direction, and this random chain includes a plurality of guide plate groups, a plurality of repeating unit, many first chain axles, and many second chain axles, guide plate group extends along this length direction and arranges, and each guide plate group includes two relative guide plate along this width direction interval, and each guide plate is formed with along this length direction front and back spaced preceding guide plate hole and back guide plate hole, the repeating unit extends along this length direction and arranges, and each repeating unit includes that one is located corresponding this guide plate group's this guide plate intermediate chain piece along this width direction interval, and two interior chain pieces, and each intermediate chain piece is formed with along this length direction front and back spaced preceding intermediate chain piece hole and back intermediate chain piece hole, and each interior chain piece is located along this width direction intermediate chain piece and corresponding between the guide plate, and front inner sheet holes and rear inner sheet holes are formed at intervals in the length direction, each first chain shaft penetrates through the front inner sheet hole of one guide sheet group and the front middle sheet hole of one corresponding repeating unit and the rear inner sheet hole of the other adjacent repeating unit, each second chain shaft penetrates through the rear guide sheet hole of one guide sheet group and the rear middle sheet hole of one repeating unit and the front inner sheet hole, each middle chain sheet and each inner chain sheet which are arranged along the width direction of each repeating unit are randomly selected from one of a plurality of tooth sheets with different structures, each middle chain sheet which is arranged in a row along the length direction is randomly selected from one of the tooth sheets, and each inner chain sheet which is arranged in a row along the length direction is randomly selected from one of the tooth sheets.

Random chain, it is individual along N of this length direction range each repeating unit in the repeating unit, it is not repeated with other arbitrary repeating unit, and N is 2 to 8 integers.

The utility model discloses random chain extends along length direction lengthwise to, and defines out the width direction that is transversal this length direction, and this random chain includes a plurality of guide plate groups, a plurality of repeating unit, many first chain axles, and many second chain axles, guide plate group extends along this length direction and arranges, and each guide plate group includes two relative guide plate along this width direction interval, and each guide plate is formed with along this length direction front and back spaced preceding lamella hole and back guide plate hole, the repeating unit extends along this length direction and arranges, and each repeating unit includes two along this width direction interval lie in corresponding this guide plate group the well chain piece between the guide plate to and three interior chain pieces, well chain piece is spaced each other along this width direction, and well chain piece is formed with along this length direction front and back spaced preceding well piece hole and back well piece hole in each, and one of them interior chain piece of each repeating unit lie in along this width direction adjacent well chain piece, each of the other two inner links of each repeating unit is located between the middle links and the guide links adjacent to each other in the width direction, each inner link is formed with a front inner link hole and a rear inner link hole spaced back and forth in the length direction, each first link is inserted through the front link hole of one of the guide link sets and the front middle link hole of the corresponding one of the repeating units and the rear inner link hole of the other adjacent repeating unit, each second link is inserted through the rear guide link hole of one of the guide link sets and the rear middle link hole and the front inner link hole of the one of the repeating units, each of the middle links and the inner links arranged in the width direction of each repeating unit is randomly selected from one of a plurality of kinds of tooth pieces having different structures, each of the middle links arranged in a line in the length direction is randomly selected from one of the tooth pieces, each of the inner links aligned in a row in the length direction is randomly selected from one of the tooth pieces.

Random chain, it is individual along N of this length direction range each repeating unit in the repeating unit, it is not repeated with arbitrary other repeating unit, and N is 2 to 32 integer.

The random chain has the following effects: each of the middle chain pieces and the inner chain pieces arranged in the width direction and each of the middle chain pieces and the inner chain pieces arranged in the length direction are randomly selected from one of the first tooth piece and the second tooth piece, and the random chain has a bidirectional random design, so that the running noise reduction effect is better.

Drawings

Other features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a top view illustrating a prior art random chain;

FIG. 2 is a cross-sectional view illustrating a first embodiment of the random chain of the present invention;

FIG. 3 is a side view illustrating the configuration of one of the plurality of guide tabs employed in the first embodiment;

fig. 4 is a side view illustrating a configuration of a first blade employed in the first embodiment;

fig. 5 is a side view illustrating a second blade configuration employed in the first embodiment;

FIG. 6 is a schematic view comparing the difference in configuration of the first and second teeth;

FIG. 7 is a diagram illustrating the composition of the repeating units of groups 1 through 24 of a random example of the first embodiment;

FIG. 8 is a schematic diagram illustrating the composition of the repeating units of groups 25 through 48 of the random example of the first embodiment;

FIG. 9 is a line drawing illustrating the test results of the NVH noise reduction test performed on the first embodiment with 21 tooth gears with an original chain and a one-way random chain;

FIG. 10 is a line drawing illustrating the test results of the NVH noise reduction test of the first embodiment with the original chain and the one-way random chain in 42 tooth gears;

FIG. 11 is a schematic cross-sectional view illustrating a second embodiment of the random chain of the present invention;

fig. 12 is a schematic cross-sectional view illustrating a third embodiment of the random chain of the present invention.

Detailed Description

In the following description, similar or identical elements will be denoted by the same reference numerals.

Referring to fig. 2 to 6, a first embodiment of the random chain of the present invention extends along a length direction D1 and defines a width direction D2 perpendicular to the length direction D1.

The first embodiment includes a plurality of guide vane sets 2 extending along the length direction D1, a plurality of repeating units 3 extending along the length direction D1 and located between the guide vane sets 2, and a plurality of first chain shafts 4 and a plurality of second chain shafts 5 for connecting the guide vane sets 2 and the repeating units 3 in series.

Each guide piece group 2 includes two guide pieces 21 facing each other at an interval in the width direction D2. Each guide piece 21 is configured as shown in fig. 3, and is formed with a front guide piece hole 211 and a rear guide piece hole 212 spaced back and forth along the length direction D1.

Each repeating unit 3 includes two middle chain pieces 31 and four inner chain pieces 32, which are stacked on each other and spaced apart from each other between the guide pieces 21 of a corresponding one of the guide piece sets 2.

The middle chain sheet 31 of each repeating unit 3 is opposite to the corresponding guide sheet 21 of the guide sheet set 2 in position interval. Each of the middle chain pieces 31 is formed with a front middle piece hole 311 and a rear middle piece hole 312 which are spaced back and forth along the length direction D1.

Each front middle piece hole 311 is spaced opposite to the corresponding front piece hole 211 along the width direction D2. Each rear center piece hole 312 is spaced opposite to the corresponding rear guide piece hole 212 in the width direction D2.

The inner links 32 of each repeating unit 3 are divided into one group by two pieces, and the inner links 32 of the same group are overlapped with each other in the width direction D2 and staggered with the guide piece 21 and the middle link 31 in the length direction. Each group of the inner links 32 is located between the corresponding middle link 31 and the corresponding guide piece 21 along the width direction D2.

Each of the inner links 32 is formed with a front inner link hole 321 and a rear inner link hole 322 which are spaced back and forth in the length direction D1. Since each inner link 32 is staggered with the guide piece 21 and the middle link 31 along the length direction D1, each front inner link hole 321 is opposite to the corresponding rear guide piece hole 212 and the rear middle piece hole 312 along the width direction D2, and each rear inner link hole 322 is opposite to the corresponding front guide piece hole 211 and the front middle piece hole 311 along the width direction D2.

Each first chain shaft 4 is inserted into the front blade hole 211 of one of the blade groups 2 and the front blade hole 311 of the corresponding one of the repeating units 3 and the rear blade hole 322 of the adjacent other repeating unit 3. Each second chain shaft 5 is inserted into the rear guide plate hole 212 of one of the guide plate groups 2 and the rear middle plate hole 312 and the front inner plate hole 321 of one of the repeating units 3.

Each of the middle chain pieces 31 and the inner chain pieces 32, which are arranged in the width direction D2 for each repeating unit 3, is randomly selected from one of a plurality of tooth pieces S, S' having different structures from each other. Each of the middle chain pieces 31 aligned in the length direction D1 is randomly selected from one of the tooth pieces S, S'. Each of the inner links 32 aligned in the length direction D1 is randomly selected from one of the teeth S, S'.

Specifically, each of the middle link plates 31 and the inner link plates 32, which are arranged along the width direction D2, of each repeating unit 3 is randomly selected from one of a first tooth plate a shown in fig. 4 and 6 and a second tooth plate B shown in fig. 5 and 6, which are different from each other in structure. Each of the middle chain plates 31 aligned in the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B. Each of the inner links 32 aligned in the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B.

In addition, in another random aspect of the first embodiment, each of the N repeating units 3 arranged in the longitudinal direction D1 may be random so as not to overlap with any other repeating unit 3, depending on the chain length. Wherein N is an integer of 2 to 64(2^ 6).

In the first embodiment, each of the middle link 31 and the inner link 32 is randomly selected from one of the first tooth a and the second tooth B, as shown in fig. 7 and 8. The first tooth piece A and the second tooth piece B are different in that the left upper corner and the right upper corner of the first tooth piece A are provided with cutting designs, and inverted V-shaped concave parts of the first tooth piece A and the second tooth piece B are slightly different. The difference between the first tooth plate a and the second tooth plate B is shown in fig. 6, wherein the solid line indicates the first tooth plate a, and the dotted line indicates the second tooth plate B.

Specifically, each first tooth a includes a first long side a1 extending along the length direction D1, a first concave side a2 spaced apart from the first long side a1 and recessed toward the first long side a1, two first short oblique sides A3 extending from the first long side a1 back to the first concave side a2, two first arc sides a4 protruding from the first concave side a2 in an arc direction opposite to the first long side a1, two first long oblique sides a5 extending from the first arc sides a4 back to the first long side a1, and two first side arc sides A6 connected between the first long oblique sides a5 and the first short oblique sides A3.

Each second tooth B includes a second long side B1 extending along the length direction D1, a second concave side B2 spaced apart from the second long side B1 along the width direction D2 and recessed toward the second long side B1, two second arc sides B3 arc-protruded from the second concave side B2 along a direction opposite to the second long side B1, two second long oblique sides B4 extending from the second arc sides B3 to the second long side B1, and two second side arc sides B5 connected between the second long oblique sides B4 and the second long side B1.

As can be seen from a comparison of fig. 6, the teeth of the first concave side a2 of the first tooth plate a are wider, i.e. define a smaller space of the inverted V-shaped recess, while the teeth of the second concave side B2 of the second tooth plate B are narrower, i.e. define a larger space of the inverted V-shaped recess.

Test of noise reduction Effect

The noise reduction effect test (NVH test) described below was performed on the first embodiment together with one original chain and one unidirectional random chain, and the test results were recorded in fig. 9 and 10 and tables 1 and 2.

All the middle chain plates 31 and all the inner chain plates 32 of the original chain are selected from the first tooth plates a.

The unidirectional random chain differs from the first embodiment in that: the arrangement was random along the length direction D1, but was regular along the width direction D2. Specifically, the tooth types of two adjacent chain plates arranged side by side along the width direction D2 in each repeating unit 3 are the same, but the tooth type of each chain plate arranged along the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B.

In other words, it can also be said that the difference between the first embodiment and the unidirectional random chain is that the first embodiment is entirely random, rather than partially random and partially regular, along the width direction D2. Specifically, although the tooth types of the two adjacent side-by-side chain plates corresponding to the position of D2 in the width direction may be the same randomly in the first embodiment, the same regularity will not be obtained in the tooth types of the two adjacent side-by-side chain plates corresponding to the position of D2 in the width direction.

Noise-Vibration-Harshness (Noise-Vibration-Harshness) test, NVH test

The first embodiment was engaged with the original chain, then with a 21-tooth gear and a 42-tooth gear, and during operation, sound was picked up with a microphone in the presence of air as the medium, and decibels of noise generated during the test were plotted against the rotational speed of the gears, as shown in fig. 9 and 10. Fig. 9 shows the test results of the gear test with 21 teeth, and fig. 10 shows the test results of the gear test with 42 teeth. Since the different sound frequencies of the noises generated when the gears with different tooth numbers are operated in cooperation with the chain are different, the test with the gear with 21/42 teeth will be referred to as the 21/42 order sound test in the following description. The numerical values shown in tables 1 and 2 below are Root Mean Square (RMS) values obtained by subjecting a noise signal to root mean square processing by a measuring instrument, and the lower the numerical value, the lower the corresponding decibel value of noise.

It can be seen from tables 1 and 2 that, in the 21 or 42 order sound test, the values in table 1 of the first embodiment are lower than those in table 1 of the conventional chain and the unidirectional random chain, which means that the noise reduction result is better, and especially the noise reduction effect of the first embodiment is especially superior under the conditions of the high rotation speed range (4000 rpm-5000 rpm) of the 21 order sound test and the rotation speed range (1500 rpm-2500 rpm) of the 42 order sound test.

Referring to fig. 11, a second embodiment of the random chain of the present invention is similar to the first embodiment except that each repeating unit 3 is different.

Each repeating unit 3 includes a middle link 31 between the guide pieces 21 of a corresponding one of the guide piece sets 2, and two inner links 32. Each inner link 32 of each repeating unit 3 is located between two front and back adjacent middle links 31 and two front and back adjacent guide links 21.

Each first chain shaft 4 is inserted into the front guide sheet hole 211 of one guide sheet group 2 and the front middle sheet hole 311 of the corresponding one of the repeating units 3 and the rear inner sheet hole 322 of the adjacent other repeating unit 3. Each second chain shaft 5 is inserted into the rear guide plate hole 212 of one of the guide plate sets 2 and the rear middle plate hole 312 and the front inner plate hole 321 of one of the repeating units 3.

Each of the middle link 31 and the inner link 32, which are arranged along the width direction D2, of each repeating unit 3 is randomly selected from one of the first tooth a and the second tooth B having different structures. Each of the middle chain plates 31 aligned in the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B. Each of the inner links 32 aligned in the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B.

In addition, in another random aspect of the second embodiment, each of the N repeating units 3 arranged in the longitudinal direction D1 may be randomly arranged so as not to overlap with any other repeating unit 3, depending on the chain length. Wherein N is an integer of 2 to 8(2^ 3).

Referring to fig. 12, a third embodiment of the random chain of the present invention is similar to the first embodiment except that each repeating unit 3 is different.

Each repeating unit 3 includes two middle links 31 and three inner links 32, which are spaced apart from each other and located between the guide pieces 21 of the corresponding one of the guide piece sets 2. The middle chain pieces 31 are spaced apart from each other in the width direction D2 and are opposite to the guide piece 21 of a corresponding one of the guide piece sets 2 in the width direction D2. The inner links 32 are located between the middle links 31 adjacent to each other in the width direction. Each of the other two of the inner links 32 located on both sides of the one of the inner links 32 is located between the middle link 31 and the guide piece 21 adjacent in the width direction.

Each of the middle link plates 31 and the inner link plates 32, which are arranged in the width direction D2 for each repeating unit 3, is randomly selected from the first tooth plate a and the second tooth plate B having different structures. Each of the middle chain plates 31 aligned in the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B. Each of the inner links 32 aligned in the length direction D1 is randomly selected from one of the first tooth plate a and the second tooth plate B.

In addition, in another random aspect of the third embodiment, each of the N repeating units 3 arranged in the longitudinal direction D1 may be randomly arranged so as not to overlap with any other repeating unit 3, depending on the chain length. Wherein N is an integer from 2 to 32(2^ 5).

To sum up, the utility model discloses the efficiency of the random chain of three kinds of embodiments lies in: each of the middle chain plates 31 and the inner chain plates 32 arranged in the width direction D2 and each of the middle chain plates 31 and the inner chain plates 32 arranged in the length direction D1 are randomly selected from one of the first tooth plates a and the second tooth plates B, and the present invention has a bidirectional random design, so that the resonance noise generated by the collision with the gear can be effectively reduced due to the irregular characteristic, and the effect of reducing the running noise is better.

The above description is only an embodiment of the present invention, and the scope of the claims of the present invention should not be limited thereto, and the equivalent modifications made according to the claims and the description of the present invention should be covered by the scope of the claims of the present invention.

Claims

1. A random chain, extending along a length direction and defining a width direction transverse to the length direction, the random chain comprising a plurality of guide plate groups, a plurality of repeating units, a plurality of first chain shafts and a plurality of second chain shafts, the guide plate groups extending along the length direction, each guide plate group comprising two guide plates spaced opposite to each other along the width direction, each guide plate being formed with a front guide plate hole and a rear guide plate hole spaced back and forth along the length direction, the repeating units extending along the length direction, each repeating unit comprising two middle chain plates stacked on each other and spaced apart from each other along the width direction between the guide plates of the corresponding guide plate group, and four inner chain plates, each middle chain plate being formed with a front middle plate hole and a rear middle plate hole spaced back and forth along the length direction, each two inner chain plates being stacked on each other along the width direction in a group, and is located between the corresponding said middle chain sheet and the corresponding said guide sheet along the width direction, each inner chain sheet is formed with front inner sheet hole and back inner sheet hole spaced from each other along the length direction, each first chain shaft is through-set in the front guide sheet hole of one of the guide sheet groups and the front middle sheet hole of one of the corresponding repeat units and the back inner sheet hole of the other adjacent repeat unit, each second chain shaft is through-set in the back guide sheet hole of one of the guide sheet groups and the back middle sheet hole of one of the repeat units and the front inner sheet hole, characterized in that: each of the medium chain pieces and the inner chain pieces, each of which is arranged in the width direction, of each repeating unit is randomly selected from one of a plurality of tooth pieces having different structures, each of the medium chain pieces, each of which is arranged in a row in the length direction, is randomly selected from one of the tooth pieces, and each of the inner chain pieces, each of which is arranged in a row in the length direction, is randomly selected from one of the tooth pieces.

2. The random chain of claim 1, wherein: each of the medium chain pieces and the inner chain pieces arranged in the width direction of each repeating unit is randomly selected from one of a first tooth piece and a second tooth piece which are different in structure, each of the medium chain pieces arranged in a row in the length direction is randomly selected from one of the first tooth piece and the second tooth piece, and each of the inner chain pieces arranged in a row in the length direction is randomly selected from one of the first tooth piece and the second tooth piece.

3. The random chain of claim 2, wherein: each first tooth sheet comprises a first long edge extending along the length direction, a first concave edge spaced from the first long edge and recessed towards the first long edge, two first short bevel edges extending from the first long edge back to the first concave edge, two first arc edges protruding from the first concave edge along a direction opposite to the first long edge, two first long bevel edges extending from the first arc edges back to the first long edge respectively, and two first side arc edges connected between the first long bevel edges and the first short bevel edges, each second tooth sheet comprises a second long edge extending along the length direction, a second concave edge spaced from the second long edge along the width direction and recessed towards the second long edge, two second arc edges protruding from the second concave edge along a direction opposite to the second long edge, and two second long bevel edges extending from the second arc edges back to the second long edge respectively, and two second side arc edges connected between the second long oblique edge and the second long edge.

4. The random chain of claim 1, wherein: each of the N repeating units arranged along the length direction is not repeated with any other repeating unit, and N is an integer of 2 to 64.

5. A random chain extends along the length direction and defines a width direction transverse to the length direction, the random chain comprises a plurality of guide sheet groups, a plurality of repeating units, a plurality of first chain shafts and a plurality of second chain shafts, the guide sheet groups extend and are arranged along the length direction, each guide sheet group comprises two guide sheets opposite to each other at intervals along the width direction, each guide sheet is provided with a front guide sheet hole and a rear guide sheet hole which are spaced back and forth along the length direction, the repeating units extend and are arranged along the length direction, each repeating unit comprises a middle chain sheet and two inner chain sheets, each middle chain sheet is provided with a front middle sheet hole and a rear middle sheet hole which are spaced back and forth along the length direction, each inner chain sheet is positioned between the middle chain sheet and the corresponding guide sheet along the width direction, and a front inner sheet hole and a rear inner sheet hole are formed at intervals along the length direction, each first chain shaft is arranged in the front inner sheet hole of one guide sheet group and the front middle sheet hole of one corresponding repeating unit and the rear inner sheet hole of the other adjacent repeating unit in a penetrating manner, each second chain shaft is arranged in the rear guide sheet hole of one guide sheet group and the rear middle sheet hole of one repeating unit and the front inner sheet hole in a penetrating manner, and the device is characterized in that: each of the medium chain pieces and the inner chain pieces, which are arranged in the width direction of each repeating unit, is randomly selected from one of a plurality of tooth pieces with different structures, each of the medium chain pieces, which are arranged in a row in the length direction, is randomly selected from one of the tooth pieces, and each of the inner chain pieces, which are arranged in a row in the length direction, is randomly selected from one of the tooth pieces.

6. The random chain of claim 5, wherein: each of the medium chain pieces and the inner chain pieces arranged in the width direction of each repeating unit is randomly selected from one of a first tooth piece and a second tooth piece which are different in structure, each of the medium chain pieces arranged in a row in the length direction is randomly selected from one of the first tooth piece and the second tooth piece, and each of the inner chain pieces arranged in a row in the length direction is randomly selected from one of the first tooth piece and the second tooth piece.

7. The random chain of claim 6, wherein: each first tooth sheet comprises a first long edge extending along the length direction, a first concave edge spaced from the first long edge and recessed towards the first long edge, two first short bevel edges extending from the first long edge back to the first concave edge, two first arc edges protruding from the first concave edge along a direction opposite to the first long edge, two first long bevel edges extending from the first arc edges back to the first long edge respectively, and two first side arc edges connected between the first long bevel edges and the first short bevel edges, each second tooth sheet comprises a second long edge extending along the length direction, a second concave edge spaced from the second long edge along the width direction and recessed towards the second long edge, two second arc edges protruding from the second concave edge along a direction opposite to the second long edge, and two second long bevel edges extending from the second arc edges back to the second long edge respectively, and two second side arc edges connected between the second long oblique edge and the second long edge.

8. The random chain of claim 5, wherein: each of the N repeating units arranged along the length direction is not repeated with any other repeating unit, and N is an integer of 2 to 8.

9. A random chain, which extends along the length direction and defines a width direction crossing the length direction, the random chain comprises a plurality of guide sheet groups, a plurality of repeating units, a plurality of first chain shafts and a plurality of second chain shafts, the guide sheet groups extend and are arranged along the length direction, each guide sheet group comprises two guide sheets which are opposite to each other at intervals along the width direction, each guide sheet is provided with a front guide sheet hole and a rear guide sheet hole which are spaced back and forth along the length direction, the repeating units extend and are arranged along the length direction, each repeating unit comprises two middle chain sheets which are spaced apart from each other along the width direction and are positioned between the guide sheets of the corresponding guide sheet group, and three inner chain sheets which are spaced apart from each other along the width direction, each middle chain sheet is provided with a front middle sheet hole and a rear middle sheet hole which are spaced back and forth along the length direction, one inner chain sheet of each repeating unit is positioned between the middle chain sheets which are adjacent along the width direction, each of the other two inner links of each repeating unit is located between the middle link and the guide link adjacent to each other in the width direction, each inner link is formed with a front inner link hole and a rear inner link hole spaced back and forth in the length direction, each first link shaft is inserted into the front inner link hole of one of the guide link groups and the front middle link hole of the corresponding one of the repeating units and the rear inner link hole of the other adjacent repeating unit, and each second link shaft is inserted into the rear guide link hole of one of the guide link groups and the rear middle link hole and the front inner link hole of the one of the repeating units, wherein: each of the medium chain pieces and the inner chain pieces, each of which is arranged in the width direction, of each repeating unit is randomly selected from one of a plurality of tooth pieces having different structures, each of the medium chain pieces, each of which is arranged in a row in the length direction, is randomly selected from one of the tooth pieces, and each of the inner chain pieces, each of which is arranged in a row in the length direction, is randomly selected from one of the tooth pieces.

10. The random chain of claim 9, wherein: each of the medium chain pieces and the inner chain pieces arranged in the width direction of each repeating unit is randomly selected from one of a first tooth piece and a second tooth piece which are different in structure, each of the medium chain pieces arranged in a row in the length direction is randomly selected from one of the first tooth piece and the second tooth piece, and each of the inner chain pieces arranged in a row in the length direction is randomly selected from one of the first tooth piece and the second tooth piece.

11. The random chain of claim 10, wherein: each first tooth sheet comprises a first long edge extending along the length direction, a first concave edge spaced from the first long edge and recessed towards the first long edge, two first short bevel edges extending from the first long edge back to the first concave edge, two first arc edges protruding from the first concave edge along a direction opposite to the first long edge, two first long bevel edges extending from the first arc edges back to the first long edge respectively, and two first side arc edges connected between the first long bevel edges and the first short bevel edges, each second tooth sheet comprises a second long edge extending along the length direction, a second concave edge spaced from the second long edge along the width direction and recessed towards the second long edge, two second arc edges protruding from the second concave edge along a direction opposite to the second long edge, and two second long bevel edges extending from the second arc edges back to the second long edge respectively, and two second side arc edges connected between the second long oblique edge and the second long edge.

12. The random chain of claim 9, wherein: each of the N repeating units arranged along the length direction is not repeated with any other repeating unit, and N is an integer of 2 to 32.