Title of Invention

"SILENT CHAIN TYPE TRANSMISSION MECHANISM"

Abstract

[OBJECT] The present invention provides a silent chain type transmission mechanism comprising sprockets and a silent chain, and facilitating the assembly of the sprockets and the silent chain. [CONSTITUTION] A silent chain type transmission mechanism comprises sprockets (7); and a silent chain (8) comprising link plates (9) of a profile conforming to the profile of the teeth (12) of the sprockets (7), and guide plates (10) linking the link plates (9), and wound around the sprockets (7). Each of the sprockets (7) is marked on a side surface thereof with an identification mark (14) of the shape of the guide plates (10) or the link plates (9) for identifying the shape of the guide plates (10) or the link plates (9) of the silent chain (8).

Full Text

[DETAILED DESCRIPTION OF THE INVENTION] [0001] [Field of Utilization in Industry] The present invention relates to a silent chain type transmission mechanism and, more particularly, to a silent chain type transmission mechanism comprising a salient chain and sprockets, and facilitating work for winding the silent chain around the sprockets. [Related art] In most chain type transmission mechanisms the pin bushes of a chain engage with the teeth of a sprocket for power transmission. Such a chain type transmission mechanism is liable to generate noise because the pin bushes strike against the sprocket when the pin bushes engage with the teeth of the sprocket. According to the present invention there is provided a silent chain type transmission mechanism comprising: sprockets; and a silent chain having link plates of a profile conforming to the profile of the teeth of the sprockets, and guide plates linking the link plates, and wound around the sprockets; wherein each of the sprockets is marked on a side surface thereof with an identification mark for identifying the shape of the guide plates or the link plates of the silent chain. Although a silent chain is used instead of such a chain to reduce the noise generated by the chain type transmission mechanism, noise is generated inevitably when the link plates of the silent chain engage with the sprocket. A silent chain having link plates of a special shape and sprockets having teeth of a special tooth profile must be used in combination to reduce the noise. For example, if the teeth of the sprocket and the link plates are designed such that each link plate strikes the sprocket an increased number of times before the link plate engages perfectly with the tooth of the sprocket so that the generated impulsive sound has a small amplitude and a high frequency, the impulsive sound may be difficult to be heard by people. A mechanism of generating such noise having a small amplitude and a high frequency will be described with reference to the accompanying drawings. Referring to Fig. 6, the outer edge of a link plate 09 strikes only once against the tooth 012 of a sprocket 07 at a point A on the tooth 012 before the link plate 09 engages perfectly with the tooth 012 of the sprocket 07. If link plates 09 and sprockets 07 designed so that the inner edge of the link plate 09 between the adjacent teeth strikes against the tooth 012 of the sprocket 07 first at a point B on the tooth 012, and then the outer edge of the link plate 09 strikes against the next tooth 012 of the sprocket 07 at a point C are used, the impact applied by the link plate 09 to the sprocket 07 every time the link plate 09 strikes against the sprocket 07 is reduced because the same energy is spent when each link plate 09 engages with the sprocket 07 regardless of the mode of engagement of the link plate 09 with the sprocket 07. The impulsive sound thus generated by the reduced impact has a frequency twice that of an impulsive sound generated by the engagement of a sprocket and a link plate which strikes only once against the sprocket before same engages perfectly with the sprocket. Since such an impulsive sound of a high frequency is difficult to be emitted from a device provided with the chain type transmission mechanism and difficult to be heard by people, and hence such an impulsive sound sounds like low noise. [0004 ] Figs. 8 to 12 show silent chain type transmission mechanism 06 provided with a low-noise silent chain 08, disclosed in JP-U NO. 6-43396. Fig. 8 is a front view of the silent chain type transmission mechanism 06, Fig. 9 is a sectional view taken on line IX-IX in Fig. 8, Fig. 10 is a plan view of the silent chain 08, Fig. 12 is a front view of a link plate 09 of the silent chain 08, and Fig. 11 is a front view of a guide plate 010 of the silent chain 08. As shown in Fig. 12, the link plate 09 is provided in a middle portion of the inner side thereof with a recess 09a which engages with a tooth 012 of a sprocket 07, and through holes 09b in portions thereof on the opposite sides of the recess 09a, respectively. As shown in Fig. 11 the guide plate 010 is provided in a middle portion of the outer side thereof with a designed recess OlOa, and through holes OlOb in portions thereof on the opposite sides of the recess OlOa, respectively. As shown in Figs. 9 and 10, the link plates 09 are arranged in three rows, the link plates 09 of the right and the left row are displaced longitudinally relative to the link plates 09 of the middle row, the guide plates 010 are arranged longitudinally so as to coincide with the link plates 09 of the middle row, respectively, so that the guide plates 010 partly overlap the link plates 09 of the right and the left row, respectively, and pins Oil are inserted through the through holes OlOb of the guide plates 010 and the through holes 09b of the link plates 09 aligned with the through holes OlOb of the guide plates 010, respectively, to link the plurality of link plates 09 and the plurality of guide plates 010 longitudinally to construct the silent chain 08. The silent chain 08 thus constructed is wound around the sprockets 07 to construct the silent chain type transmission mechanism 06. As mentioned above, the shape of the link plates 09 and that of the teeth 012 of the sprocket 07 are designed so that each link plate 09 strikes a plurality of times against the sprocket 07 before the link plate 09 comes into perfect engagement with the sprocket 07. Therefore, the silent chain type transmission mechanism 06 generates low noise and reduces the significance of problems attributable to the noise. [0005] In the silent chain type transmission mechanism 06 employing the silent chain 08 thus constructed, the link plates 09 and the teeth 012 of the sprockets 07 are formed in the shapes of special designs as mentioned above so that the silent chain type transmission mechanism 06 may generate noise of a low level when the link plates 09 come into engagement with the sprocket '07. Therefore, the sprockets 07 cannot be used in combination with link plates of other design, and the link plates 09 cannot be used in combination with sprockets of other design. Thus, the sprocket 07 and the link plate 09 are incompatible with other link plates and other sprocket, respectively. Therefore, the link plates 09 and the sprockets 07 compatible with each other must be used in combination. Accordingly, the sprocket 07 is marked with an identification mark, such as a part number "KC6", indicating a silent chain 08 having suitable link plates 09 as shown in Fig. 8 to facilitate work for finding the suitable silent chain 08 for the sprocket 07. The operator finds a silent chain 08 having link plates 09 suitable for the sprocket 07 from drawings and service manuals, and uses the silent chain 08 thus found in combination with the sprocket 07. [0006] [Problem to be Solved by the Invention] The operator examines the identification mark, such as a part number, marked on the side surface of the sprocket 07, finds out a silent chain 08 having link plates 09 suitable for use in combination with the sprocket 07, ascertains that the silent chain 08 is suitable and winds the silent chain 08 around the sprocket 07. Therefore, the operator is unable to choose the silent chain 08 having the link plates 09 suitable for use in combination with the sprocket 07 simply by examining the identification mark marked on the side surface of the sprocket 07. The operator needs to consult drawings and service manuals to find out the suitable silent chain 08 and to ascertain that the silent chain 08 is suitable before winding the silent chain 08 around the sprocket 07 to construct a desired silent chain type transmission mechanism 06. Thus, the operator needs to have the knowledge of the correspondence between identification marks and silent chains beforehand or needs to learn the knowledge, and the assembly of the silent chain and the sprocket requires troublesome work. [0007] [Means for Solving the Problem] The present invention provides a silent chain type transmission mechanism which solves the foregoing problems and facilitate work for assembling a silent chain and a sprocket. According to an invention stated in claim 1, a silent chain type transmission mechanism comprises sprockets: and a silent chain comprising link plates of a profile conforming to the profile of the teeth of the sprockets, and guide plates linking the link plates, and wound around the sprockets/, An identification mark for identifying the profile, .of. the guide plates or the link plates of the silent chamois marked on a side surface of each of the sprockets. [0008] In the silent chain type transmission mechanism in accordance with the invention stated in claim 1, the operator is able to choose the silent chain having the link plates suitable for use in combination with the sprocket simply by examining the identification mark for identifying the profile of the guide plates or the link plates, marked on the side surface of the sprocket, which facilitates work for assembling the silent chain and the sprocket. [0009J If the identification mark marked on the side surface of each of the sprockets of the silent chain type transmission mechanism of the invention stated in claim 1 is the shape of the guide plates or the link plates as stated in claim 2, work for marking the identification mark is simplified, and the identification mark can surely be marked so that the identification mark may not be effaced and remain permanently on the sprocket. [BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS] [Fig. 1] Fig. 1 is a schematic fragmentary sectional view of 4n internal combustion engine provided with a silent chain type transmission mechanism in a preferred embodiment according to an invention stated in claims 1 and 2. [Fig. 2] Fig. 2 is an enlarged front view the silent chain transmission mechanism of Fig. 1. [Fig. 3] Fig. 3 is a schematic fragmentary sectional view of [the internal combustion engine of Fig. 1, taken on a plane including the center axis of a camshaft. [1 Fig. 4] Fig. 4 is a schematic front view of a sprocket included in the silent chain type transmission mechanism of Fig. 1. [Fig. 5] Fig .5 is a sectional view taken on line V-V in Fig. 4. [Fig. 6] Fig. 6 is a diagrammatic view of assistance in explaining a process of engagement of a link plate of a silent chain with a tooth of a sprocket. [Fig. 7] Fig. 7 is a diagrammatic view similar to Fig. 6. [Fig. 8] Fig. 8 is a front view of a conventional silent chain type transmission mechanism. [Fig. 9] Fig. 9 is a sectional view taken on line IX-IX in Fig. 8. [Fig. 10] Fig. 10 is a plan view of a silent chain included in the silent chain type transmission mechanism of Fig. 8. [Fig. 11] Fig. 11 is a front view of a link plate of the silent chain of Fig. 8. [Fig. 12] Fig. 12 is a front view of a guide plate of the silent chain of Fig. 8. [0010] [Preferred Embodiments of the Invention] Preferred embodiments of the present invention stated in claims 1 and 2 and illustrated in Figs. 1 to 5 will be described hereinafter. A silent chain type transmission mechanism 6 in a preferred embodiment according to the present invention employing a silent chain 8 is applied to an internal combustion engine 1. Referring to Figs. 1 and 3, the engine 1 has a cylinder 2 and a cylinder head 4 joined to the upper end of the cylinder 2. A camshaft 5 is rotatably supported on the cylinder head 4, a support member 13, having the shape of a thick disk is fixedly mounted on the camshaft 5, and a sprocket 7 is fastened to the support member 13. The silent chain 8 is extended between the sprocket 7 and a sprocket, not shown, fixedly mounted on a crankshaft, not shown. Indicated at 3 is a piston. [0011] The basic construction of the silent chain type transmission mechanism 6 employing the silent chain 8 is similar to the conventional silent chain type transmission mechanism 06 employing the silent chain 08 and illustrated in Figs. 8 to 12. Link plates 9 and guide plates 10 forming the silent chain 8 have the same profiles as those shown in Figs. 11 and 12, respectively, the link plates 9 are arranged longitudinally in three rows as shown in Figs. 9 and 10, the link plates 9 of the right and the left row are displaced longitudinally relative to the link plates 9 of the middle row, respectively, so that the guide plates 10 partly overlap the link plates 9 of the right and the left row, respectively, and pins 11 are inserted through the through holes of the guide plates 10 and the through holes of the link plates 9 aligned with the through holes of the guide plates 10, respectively, to link the plurality of link plates 9 and the plurality of guide plates 10 longitudinally to construct the silent chain 8. The silent chain 8 thus constructed is wound around the sprockets 7 shown in Figs. 4 and 5 to construct the silent chain type transmission mechanism 6. [0012] In this embodiment, the sprocket 7 is marked on a side surface thereof with an identification mark 14 of the same shape as that of the guide plate 10 of the silent chain 8. The identification mark 14 is a pictograph symbolizing the guide plate 10 of the silent chain 8, to be used in combination with the link plates 9 which generate the least noise unavoidably when the same engage with the teeth 12 of the sprocket 7. [0013] Therefore, the operator is able to discriminate the silent chain 8 suitable for use in combination with the sprocket 7 from the conventional chains and other silent chains and to choose the same simply by examining the identification mark 14., which simplifies work instructions, makes work for assembling the silent chain and the sprocket very easy, and hence improves serviceability without requiring additional costs. [0014] Generally, a side surface of the sprocket 7 is marked with a timing mark. If the side surface of the sprocket 7 is marked with both the timing mark and the identification mark 14 pictographically symbolizing the guide plates 10, the identification mark can be recognized without fail when assembling the engine 1. The identification mark 14 can be simply and surely marked with a marking die faced with a pattern corresponding to the identification mark 14, cannot be easily effaced and remains permanently on the sprocket 7. [0015] Although this embodiment uses the shape of the guide plates 10 as the identification mark, the shape of the link plate 9 may be used as the identification mark. Essentially, the identification mark may be of any shape provided that the operator is able to know the silent chain suitable for use in combination with the sprocket 7 simply by examining the identification mark. A label printed with the shape of the guide plates 10 or the link plates 9 may be attached with an adhesive to a side surface of the sprocket 7 instead of marking the side surface with the identification mark 14. [REFERENCE CHARACTERS] I ... Internal combustion engine, 2 ... Cylinder, 3 ... Piston, 4 ... Cylinder head, 5 ... Camshaft, 6 ... Silent chain type transmission mechanism, 7 ... Sprocket, 8 ... Silent chain, 9 ... Link plate, 10 ... Guide plate, II ... Pin, 12 ... Tooth, 13 ... Support member, 14 ... Identification mark, 15 ... Timing mark WE CLAIM: - 1. A silent chain type transmission mechanism (6) comprising: sprockets(7); and a silent chain (8) having link plates (9) of a profile conforming to the profile of the teeth (12) of the sprockets, and guide plates (10) linking the link plates (9), and wound around the sprockets (7); characterized by each of the sprockets (7) is marked on a side surface thereof with an identification mark for identifying the shape of the guide plates (10) or the link plates (9) of the silent chain (8). 2. The silent chain type transmission mechanism as claimed in claim 1, wherein the identification mark marked on the side surface of each of the sprockets is the shape of the guide plates or the link plates. 3. A silent chain type transmission mechanism substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

2650-del-1997-abstract.pdf

2650-del-1997-claims.pdf

2650-del-1997-correspondence-others.pdf

2650-del-1997-correspondence-po.pdf

2650-del-1997-description (complete).pdf

2650-del-1997-drawings.pdf

2650-del-1997-form-1.pdf

2650-del-1997-form-13.pdf

2650-del-1997-form-19.pdf

2650-del-1997-form-2.pdf

2650-del-1997-form-3.pdf

2650-del-1997-form-4.pdf

2650-del-1997-form-6.pdf

2650-del-1997-gpa.pdf

2650-del-1997-petition-137.pdf

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