Chain stretch detector

Abstract

A chain extension detection device according to this disclosure comprises a pair of rotary shafts that are provided such that a straight line joining the shaft centers thereof is parallel to the travel direction of a given chain (1) and a pair of levers that are attached so as to be capable of rotating freely around the rotary shafts. The distance between the pair of rotary shafts is set to the same distance as the chain pitch of the chain (1). The pair of levers have a pair of end parts that are capable of touching the lateral surfaces of adjacent outer links of the chain (1) or the lateral surfaces of adjacent inner links of the chain (1). The pair of end parts are formed so as to touch the chain (1) in the same way. At least one of the pair of levers has a structure provided at an end part on the reverse side from the side that touches the chain (1), and the state of the structure changes mechanically in response to variation in the relative interval between the pair of end parts of the pair of levers on the sides that touch the chain (1).

Description

[Technical field]

[0001] The present disclosure relates to a chain stretch detection device. [Background technology]

[0002] Patent Document 1 discloses a technique for measuring chain elongation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 3312326 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 can obtain information on the elongation of multiple links of a chain, but cannot obtain information on the elongation of each individual link.

[0005] The present disclosure has been made to solve the above-mentioned problems. An object of the present disclosure is to provide a chain elongation detection device that can detect elongation of a chain on a link-by-link basis. [Means for solving the problem]

[0006] The chain elongation detection device according to the present disclosure includes a pair of rotating shafts that are installed so that a straight line connecting their shaft centers is parallel to the running direction of the target chain, and a pair of levers that are attached so as to be freely rotatable around these rotating shafts. The dimension between the pair of rotating shafts is set to the same dimension as the chain pitch of the chain. The pair of levers has a pair of ends that can contact the side surfaces of adjacent outer links or adjacent inner links of the chain, and the pair of ends are formed so that the contact state with each chain is the same. At least one of the pair of levers has an end opposite to the side that comes into contact with the chain, and the state of the end is mechanically changed in response to a change in the relative distance between the ends of the pair of levers that come into contact with the chain. Alternatively, a detector is provided at the end of at least one of the pair of levers opposite the side that comes into contact with the chain, which detects information about the relative distance between the pair of ends of the levers on the side that comes into contact with the chain and electrically outputs the information. Effect of the Invention

[0007] The chain elongation detection device according to the present disclosure makes it possible to detect chain elongation on a link-by-link basis. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a general structure of a chain used for power transmission. [Diagram 2] 1 is a perspective view showing the structure of a chain elongation detection device according to a first embodiment. FIG. [Diagram 3] 1 is a perspective view showing the structure of a chain elongation detection device according to a first embodiment. FIG. [Figure 4] FIG. 2 is a perspective view showing the periphery of a detection component in the first embodiment. [Diagram 5] 1 is a front view showing a state in which a chain is not stretched while traveling in a chain elongation detection device in accordance with embodiment 1. FIG. [Figure 6] 1 is a front view showing a state in which a stretched chain is traveling in the chain elongation detection device in accordance with embodiment 1. FIG. [Figure 7] FIG. 7 is a front view showing a state in which the chain has traveled further from the state shown in FIG. 6. [Figure 8] FIG. 11 is a perspective view showing a modified example of the detection component in the first embodiment. [Figure 9] 10 is a front view showing a modified example of the detection component in the first embodiment. FIG. [Figure 10] FIG. 11 is a diagram showing a chain elongation detection device according to a second embodiment. [Figure 11] FIG. 11 is a diagram showing a first modified example of the chain elongation detection device according to the second embodiment. [Figure 12] FIG. 11 is a diagram showing a second modified example of the chain elongation detection device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described with reference to the accompanying drawings. In addition, common or corresponding elements in each drawing are given the same reference numerals, and in this disclosure, duplicated descriptions are simplified or omitted. In addition, this disclosure is not limited to the embodiments described below, and may include all combinations and modifications of the configurations disclosed by the following embodiments.

[0010] Embodiment 1 1 is a perspective view showing a general structure of a chain 1 used for power transmission. The chain 1 is a component that constitutes a power transmission structure that transmits power by the tension of the chain 1 wound around a pair of sprockets.

[0011] As shown in FIG. 1, a chain 1 is made up of outer links 11 and inner links 12 that are alternately connected. The outer link 11 is a member in which a link plate and a pin 13 are integrated. The inner link 12 is a member in which a link plate and a bush 14 are integrated. The pin 13 passes through the bush 14 and rotates and slides. In addition, a chain roller 15 is attached to the outside of the bush 14. The chain roller 15 meshes with the teeth of a pair of sprockets to transmit power.

[0012] The elongation of the chain 1 occurs mainly due to wear caused by the rotational sliding between the pins 13 and the bushes 14. As the chain 1 elongates, the distance between adjacent outer links 11 or adjacent inner links 12 increases. The dimension between the links of the chain 1 is called the "chain pitch," and this chain pitch is determined by standards according to the size of the chain 1. The elongation of the chain 1 is expressed as the elongation rate (%) from the chain pitch.

[0013] 1, the dimension of the distance between a pair of pins 13 on a particular outer link 11 does not change unless elongation occurs in the link plate of that outer link 11. Similarly, the dimension of the distance between a pair of bushes 14 on a particular inner link 12 does not change unless elongation occurs in the link plate of that inner link 12. This also shows that elongation of the chain 1 is manifested as a change in the dimension of the distance between adjacent outer links 11 or adjacent inner links 12.

[0014] The chain elongation detection device according to the present disclosure detects a dimensional change in the gap between adjacent links directly and mechanically by contacting the links. Figures 2 and 3 are perspective views showing the structure of the chain elongation detection device according to the first embodiment.

[0015] The chain elongation detection device according to this embodiment includes a base 4. A pair of levers are attached to the base 4. The pair of levers are a left lever 2 and a right lever 3. In addition, a chain guide 5 is attached to the base 4 for clamping a chain 1, the chain 1 being the object of elongation detection, and fixing the chain elongation detection device to the chain 1.

[0016] The chain elongation detection device according to the present embodiment includes a pair of rotating shafts provided on a base 4. The pair of rotating shafts are rotating shaft P2 and rotating shaft P3. The pair of rotating shafts are installed so that a straight line connecting their axial centers is parallel to the running direction of the target chain 1. The distance between the pair of rotating shafts is set to be the same as the chain pitch of the chain 1. The rotating shaft P2 is an example of a first rotating shaft according to the present disclosure. The rotating shaft P3 is an example of a second rotating shaft according to the present disclosure.

[0017] The left lever 2 is attached so as to be freely rotatable about a rotation axis P2. The right lever 3 is attached so as to be freely rotatable about a rotation axis P3. The left lever 2 is an example of a first lever according to the present disclosure. The right lever 3 is an example of a second lever according to the present disclosure.

[0018] The pair of levers have ends that can contact the side of the adjacent outer link 11 or the side of the adjacent inner link 12 of the chain 1. The pair of ends are formed so that the state of contact with each of the chain 1 is the same. Specifically, the length of the portion of the left lever 2 from the end of the chain 1 side to the rotation axis P2 is set to be the same as the length of the portion of the right lever 3 from the end of the chain 1 side to the rotation axis P3. In addition, the shapes of the ends of the left lever 2 and the right lever 3 on the chain 1 side are designed so that they will be in the same state of contact with the side of the links of the chain 1 in the same rotational posture.

[0019] In Fig. 2, the chain 1 travels toward the right side of the page. A clockwise rotational force about a rotation axis P2 is applied to the left lever 2 by a spring 6 or other means. Similarly, a clockwise rotational force about a rotation axis P3 is applied to the right lever 3 by a spring 6 or other means. The left lever 2 and the right lever 3 are each maintained in their initial positions by a stopper 7 fixed to a base 4.

[0020] 2, the left lever 2 and the right lever 3 are positioned vertically to the running direction of the chain 1. In this state, the ends of the left lever 2 and the right lever 3 on the chain 1 side are not in contact with the side surfaces of the links of the chain 1. In this state, the left lever 2 and the right lever 3 are positioned in an initial state in which they are pressed against a stopper 7 by means such as a spring 6 that applies a rotational force.

[0021] In the present disclosure, at least one of the pair of levers has an end opposite to the side in contact with the chain 1, and the structure is provided with a state that mechanically changes in response to a change in the relative distance between the pair of ends of the pair of levers on the side in contact with the chain 1. As an example, in this embodiment, as shown in FIG. 3, a member having a hole penetrating in the tangential direction of the rotation of the lever is attached to the tip of the left lever 2. A detection component 8 that is inserted into this hole and can slide is installed at the tip of the left lever 2. FIG. 4 is a perspective view showing the periphery of the detection component 8 in the first embodiment.

[0022] In Fig. 3, the left lever 2 and the right lever 3 are in an initial position pressed against the stopper 7 by a spring 6 or other means that applies a rotational force, as in Fig. 2. In this state, at the ends of both levers opposite the chain 1, the detection component 8 and the tip of the right lever 3 are in contact or spaced a certain distance apart. In the state shown in Fig. 3, the end of the detection component 8 opposite the right lever 3 does not protrude from the through hole at the tip of the left lever 2.

[0023] FIG. 5 is a front view showing the state of the chain 1 when it is running in the chain elongation detection device according to the first embodiment. FIG. 5 shows the state where the chain 1 has moved from the state shown in FIG. 3 to the right side of the paper. As described above, the pair of rotating shafts are installed so that the straight line connecting the shaft centers is parallel to the running direction of the chain 1. The dimension between the rotating shafts is set to the same dimension as the chain pitch of the chain 1. In addition, the distance from the ends of the chain 1 side of both levers to the rotating shaft is the same. And the shapes of the parts of both levers that contact the chain 1 are also the same. Therefore, when the unstretched chain 1 moves in the traveling direction, the ends of the pair of levers on the chain 1 side come into contact with the same positions of the link outer shape at the same timing. As the chain 1 moves, the pair of levers rotate at the same rotation angle about the respective rotating shafts P2 and P3. When there is no stretch in the chain 1, both levers move while maintaining parallelism. In addition, the ends of the chain 1 side and the opposite side of the two levers do not approach each other from the initially set interval. The distance between the detection component 8 installed at the tip of the left lever 2 and the tip of the right lever 3 also does not change.

[0024] Fig. 6 is a front view showing a state in which the stretched chain 1 is traveling in the chain elongation detection device according to embodiment 1. Fig. 7 is a front view showing a state in which the chain 1 has traveled further from the state shown in Fig. 6.

[0025] As described above, when there is no elongation in the chain 1, the distance between adjacent links A and B is the chain pitch p defined by the chain size. In the state shown in Figures 3 and 5, the left lever 2 and right lever 3 are in contact with adjacent links when there is no elongation in the chain 1, that is, at an interval of chain pitch p. On the other hand, in a chain 1 that has elongated by an elongation rate of α%, the distance between links A and B is the dimension expressed by the following formula (1). (1 + α / 100) × p (1)

[0026] In Fig. 6, the distance between link A and link B is larger than the chain pitch p. Specifically, the distance between link A and link B is (1+α / 100)×p. In Fig. 6, link A passes through left lever 2 and is in contact with the right lever.

[0027] When the chain 1 travels further from the state in Fig. 6 to the state in Fig. 7, link A comes into contact with the right lever 3 before link B comes into contact with the left lever 2. Then, of both levers, only the right lever 3 starts to rotate and tilt. Only the right lever 3 continues to rotate until the left lever 2 comes into contact with link B, and the tip of the right lever 3 approaches the tip of the left lever 2, pushing in the detection component 8 and causing it to slide.

[0028] The distance by which the tip of the right lever 3 approaches the tip of the left lever 2 for an assumed chain elongation rate can be determined in advance. The distance from the end of the right lever 3 on the chain 1 side to the rotation axis P3 is defined as L1. The distance from the end of the right lever 3 opposite the chain 1 side to the rotation axis P3 is defined as L2. The elongation rate of the chain 1 is then defined as α (%). The amount of movement of the chain 1 from when the right lever 3 starts to rotate due to contact with link A to when the left lever 2 starts to rotate due to contact with link B is the amount of elongation rate α (%). This amount of movement can be expressed as p × α / 100. The amount by which the end of the right lever 3 opposite the chain 1 approaches the left lever 2 during this time can be determined by the following equation (2): (p×α / 100)×(L2 / L1) ···(2)

[0029] In the initial position shown in Figure 3, the end of the detection component 8 opposite the right lever 3 does not protrude from the through hole at the tip of the left lever 2. As the chain 1 elongates, the right lever 3 rotates, pushing the detection component 8 into the through hole. If the amount of pushing until the detection component 8 protrudes from the through hole in the left lever 2 is set to be less than the amount calculated by equation (2), it can be easily visually confirmed from the outside that the chain 1 has elongated by more than a specific predetermined chain elongation rate α (%), as shown in Figure 7.

[0030] In this embodiment, a detection component 8 for indicating the presence or absence of elongation to be detected and a through hole through which the detection component 8 slides are provided at the tip of the left lever 2. The detection component 8 and a through hole through which the detection component 8 slides may be provided at the tip of the right lever 3. In addition, the mechanical structure provided at the tip of each lever may be a structure made of any mechanical element different from the detection component 8. For example, it is not limited to one that indicates elongation above a specific elongation rate, and may be a structure that simply indicates the presence or absence of elongation.

[0031] As described above, according to this embodiment, a chain elongation detection device is obtained that can check whether the chain 1 has elongated beyond a desired elongation rate, link by link, over the entire length of the chain 1. This embodiment also uses a means for notifying the outside world of the presence or absence of elongation in the chain 1 through a mechanical change. This embodiment does not require electrical wiring, and provides a chain elongation detection device that is advantageous in terms of installation and workability.

[0032] Moreover, Fig. 8 is a perspective view showing a modified example of the detection component 8 in the first embodiment. Fig. 9 is a front view showing a modified example of the detection component 8 in the first embodiment. In this modified example, the detection component 8 is configured so that it is possible to visually check from the outside whether the chain 1 has elongated beyond a certain number of elongation percentages by a mechanical change. Specifically, the detection component 8 is painted in different colors according to the distance from the tip, starting from the tip opposite the side in contact with the right lever 3.

[0033] The amount by which the tips of the levers approach each other can be expressed by the above-mentioned formula (2). By using this formula, the amount by which the levers approach each other, i.e., the amount of depression of the detection part 8, can be calculated for each of a number of specific extension rates.

[0034] Fig. 9(a) shows a state where the elongation is zero. Fig. 9(b) shows a state where the elongation rate is α1. Fig. 9(c) shows a state where the elongation rate is α2. Here, the relationship between the elongation rates is zero<α1<α2. In this modified example, as shown in Fig. 9, the maximum elongation rate of the chain 1 can be visually confirmed from the outside by distinguishing the color of the part of the detection component 8 protruding from the through hole.

[0035] Embodiment 2 Next, a chain elongation detection device according to embodiment 2 will be described. Note that illustrations and descriptions of parts that are the same as or equivalent to those in embodiment 1 will be omitted. In this embodiment, differences from embodiment 1 will be described.

[0036] Figure 10 is a diagram showing a chain elongation detection device according to embodiment 2. In this embodiment, a detector is provided at the end of at least one of the pair of levers opposite the side that comes into contact with the chain 1, for detecting information on the relative distance between the pair of ends of the pair of levers on the side that comes into contact with the chain 1 and for electrically outputting the information.

[0037] As an example, a limit switch 9 that is turned ON / OFF by detecting a certain amount of depression from the tip of the right lever 3 is provided at the tip of the left lever 2. The limit switch 9 is an example of a detector according to the present disclosure.

[0038] The limit switch 9 has the same function as the detection component 8 in the first embodiment. The limit switch 9 operates depending on whether or not the chain 1 is elongated by a specific elongation rate or more. When the chain 1 is elongated by a specific elongation rate or more, the limit switch 9 is pushed in by the right lever 3. This turns the limit switch 9 ON. A signal from this limit switch 9 is output to a separately provided signal processor 10. The signal processor 10 notifies the outside that the limit switch 9 is ON by any method such as sound, screen display, or light. This makes it easy to confirm that the chain 1 is elongated by a specific elongation rate or more. The signal processor 10 may be incorporated in the chain elongation detection device, or may be configured as an external device.

[0039] 11 is a diagram showing a first modified example of the chain elongation detection device according to embodiment 2. For example, an LED that is visible from the outside may be provided instead of the signal processing unit 10. This LED is configured to light up when the limit switch 9 is turned ON.

[0040] According to this embodiment, since information on the elongation of the chain 1 is output to the outside, there is no need to open up the area around the chain 1 or to visually inspect the chain 1 itself.

[0041] Moreover, Fig. 12 is a diagram showing a second modified example of the chain elongation detection device according to the second embodiment. For example, instead of the limit switch 9, a displacement sensor 20 may be provided at the tip of the left lever 2 as a displacement detection means for detecting the relative distance between opposing objects. The displacement sensor 20 is capable of non-contact measurement using optical or magnetic means. The displacement sensor 20 electrically outputs information on the amount of approach between the tip of the left lever 2 and the tip of the right lever 3. The information output from the displacement sensor 20 is processed by, for example, the signal processing unit 10. This modified example also makes it possible to easily detect the elongation of the chain 1 on a link-by-link basis. [Industrial Applicability]

[0042] A chain elongation detection device according to the present disclosure is used, for example, to detect elongation of a chain that constitutes a power transmission mechanism. [Explanation of symbols]

[0043] REFERENCE SIGNS LIST 1 chain, 2 left lever, 3 right lever, 4 base, 5 chain guide, 6 spring, 7 stopper, 8 detection part, 9 limit switch, 10 signal processing part, 11 outer link, 12 inner link, 13 pin, 14 bush, 15 chain roller, 20 displacement sensor

Claims

1. A pair of rotating shafts are installed so that the line connecting the shaft centers is parallel to the running direction of the target chain; a pair of levers attached so as to be freely rotatable about the rotation shaft; Equipped with a dimension between the pair of rotating shafts is set to be equal to a chain pitch of the chain; The pair of levers have a pair of ends capable of contacting side surfaces of adjacent outer links or side surfaces of adjacent inner links of the chain, and the pair of ends are formed so that their contact states with the chain are the same; A chain elongation detection device characterized in that at least one of the pair of levers has an end opposite to the side that contacts the chain, and the end structure is provided whose state mechanically changes in response to a change in the relative distance between the pair of ends of the pair of levers on the side that contacts the chain.

2. The chain elongation detection device as described in claim 1, characterized in that a detection component is provided at the end of at least one of the pair of levers opposite the side that contacts the chain, which makes it possible to visually observe from the outside through a mechanical change whether the chain has elongated beyond a predetermined specific elongation rate.

3. The chain elongation detection device according to claim 2, wherein the detection component is configured to make it possible to visually observe from the outside when the chain has elongated beyond a plurality of specific elongation percentages through a mechanical change.

4. A pair of rotating shafts are installed so that the line connecting the shaft centers is parallel to the running direction of the target chain; a pair of levers attached so as to be freely rotatable about the rotation shaft; Equipped with a dimension between the pair of rotating shafts is set to be equal to a chain pitch of the chain; The pair of levers have a pair of ends capable of contacting side surfaces of adjacent outer links or side surfaces of adjacent inner links of the chain, and the pair of ends are formed so that their contact states with the chain are the same; A chain elongation detection device characterized in that a detector is provided at the end of at least one of the pair of levers opposite the side that contacts the chain, which detects information about the relative distance between the pair of ends of the pair of levers on the side that contacts the chain and outputs the information electrically.

5. 5. The chain elongation detection device according to claim 4, wherein the detector is configured as a switch that operates in response to whether or not the chain has elongated by a specific percentage or more.

6. 5. The chain elongation detection device according to claim 4, wherein the detector electrically outputs information on the amount of approach between the ends of the pair of levers opposite to the side in contact with the chain.

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