Patent Application
20060014600
1. Field of the Invention
The invention relates to a drive chain, more particularly to a lightweight drive chain.
2. Description of the Related Art
Referring to
It is desirable to reduce the overall weight of the drive chain for efficient use of power without sacrificing the structural integrity of the drive chain. Furthermore, it is desirable to reduce the contact areas of the inner and outer chain plates 11,12 to avoid dirt accumulation therebetween, which can result in abrading of the inner and outer chain plates 11,12 that can lead to a shorter service life for the drive chain 1.
Therefore, the object of the present invention is to provide a drive chain, which is relatively lightweight as compared to the conventional drive chain.
Accordingly, the lightweight drive chain of this invention includes a plurality of parallel pairs of outer chain plates, a plurality of parallel pairs of inner chain plates, and a plurality of pins.
Each pair of the inner chain plates is disposed between two adjacent pairs of the outer chain plates. The pins connect the inner chain plates to the outer chain plates.
Each of the outer chain plates has a first inner surface, a first outer surface opposite to the first inner surface, a pair of first end portions spaced apart from each other along a first longitudinal axis, a first connecting portion interconnecting the first end portions along the first longitudinal axis, and a pair of first pin holes that are formed respectively in the first end portions and that extend through the first inner and outer surfaces. Each of the first pin holes is defined by a first hole periphery.
Each of the inner chain plates has a second outer surface, a second inner surface opposite to the second outer surface, a pair of second end portions spaced apart from each other along a second longitudinal axis, a second connecting portion interconnecting the second end portions, and a pair of second pin holes that are formed respectively in the second end portions and that extend through the second inner and outer surfaces.
Each of the outer chain plates further has a pair of first weight-reducing slots, each of which extends radially from the first hole periphery of a respective one of the first pin holes. The first weight-reducing slots are not in spatial communication with each other.
Each of the inner chain plates further has a second weight-reducing slot disposed between the second pin holes.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:
Referring to
Referring to
In this embodiment, each of the first weight-reducing slots 36 has an open end portion 361 at the first hole periphery 351 of the respective one of the first pin holes 35, a closed end portion 362 opposite to the open end portion 361, and an intermediate expanded portion 363 between the open and closed end portions 361,362. Each of the first weight-reducing slots 36 has a width that is reduced from the intermediate expanded portion 363 to each of the open and closed end portions 361,362. The open end portion 361 has an opening 365 smaller than a diameter (D) of the respective one of the first pin holes 35 and smaller than a largest width at the intermediate expanded portion 363. Each of the first pin holes 35 has a center 352. The opening 365 of the open end portion 361 of each of the first weight-reducing slots 36 defines an angle (β) ranging from 30 to 60 degrees with respect to the center 352 of the respective one of the first pin holes 35.
Each of the first end portions 33 is formed with two reinforcing ribs 331 that protrude from the first outer surface 32, that are radially offset from the first pin hole 35, and that are disposed on opposite sides of the first longitudinal axis (X). Each of the reinforcing ribs 331 forms an acute angle (a) with respect to the first longitudinal axis (X). Preferably, the acute angle is 45 degrees. The reinforcing ribs 331 are formed by punching at the first inner surface 31 such that the first inner surface 31 is formed with recesses 332 corresponding to the reinforcing ribs 331.
Preferably, the first connecting portion 34 is formed with an inclined primary reinforcing ridge 341 that protrudes from the first outer surface 32 and that is inclined with respect to the first longitudinal axis (X). The primary reinforcing ridge 341 is formed by punching at the first inner surface 31 such that the first inner surface 31 is formed with a primary groove 341′ corresponding to the primary reinforcing ridge 341. The first connecting portion 34 is further formed with an inclined secondary reinforcing ridge 342 that crosses the primary reinforcing ridge 341 and that protrudes from the first outer surface 32 at a distance less than that of the primary reinforcing ridge 341 as best shown in
Referring to
Each of the second pin holes 45 is defined by a second hole periphery 451. Each of the inner chain plates 4 further has a pair of annular flanges 47 protruding from the second inner surface 42 at the second hole periphery 451 of a respective one of the second pin holes 45.
Each of the tubular rollers 21 is sleeved rotatably on a confronting pair of the annular flanges 47 of a corresponding parallel pair of the inner chain plates 4.
In view of the aforesaid, the following effects can by achieved by the lightweight drive chain of this invention:
1). Each of the outer chain plates 3 is formed with a pair of the first weight-reducing slots 36. Each of the inner chain plates 4 is formed with the second weight-reducing slot 46. Each of the pins 22 is tubular. Therefore, the overall weight of the drive chain 2 of this invention can be substantially reduced as compared to the conventional drive chain 1.
2) Each of the first end portions 33 of each of the outer chain plates 3 is formed with two reinforcing ribs 331. The first connecting portion 34 of each of the outer chain plates 3 is formed with the primary and secondary reinforcing ridges 341,342. Furthermore, the reinforcing ribs 331 are formed at positions where breaking of a conventional outer chain plate are likely to occur. Therefore, the structural strength of each of the outer chain plates 3 can be reinforced.
3) Although each of the first weight-reducing slots 36 is in spatial communication with a corresponding one of the first pin holes 35, the opening 365 of the open end portion 361 of each of the first weight-reducing slots 36 defines the angle (β) ranging from 30 to 60 degrees, which can prevent each of the pins 22 from moving into a corresponding one of the first weight-reducing slots 36.
4) The overlapping area between the first end portions 33 of the outer chain plates 3 and the adjacent second end portions 43 of the inner chain plates 4 is reduced, thereby minimizing dirt accumulation therebetween.
5) Each of the tubular rollers 21 is sleeved rotatably on a confronting pair of the annular flanges 47 of a corresponding parallel pair of the inner chain plates 4, which further reinforces the structural strength of the drive chain 2.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
