Chain

Details Chain Chain

1999-12-01

2001-10-30

Jones, David (Department: 3725)

Chain, staple, and horseshoe making

Chains

C059S004000, C059S084000, C474S206000

Reexamination Certificate

active

06308510

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
Priority is claimed to British Patent Application No. 9704040.6, filed Feb. 27, 1997, and to PCT Application No. PCT/GB98/00557, filed Feb. 24, 1998.
BACKGROUND OF THE INVENTION
The present invention relates to a chain and more particularly, but not exclusively, to a drive chain or lifting chain of the kind having a plurality of inner links connected by intermediate outer links.
Conventional roller chains comprise a sequence of inner links interconnected by intermediate outer links and pins which are received in said inner links and are secured by interference fit in holes provided in the outer links. Each pin is located in a fixed bush which supports a rotatable cylindrical roller and which extends between opposed inner link plates. In some harsh applications shock loads to a drive or lifting arrangement are carried by the chain resulting in chain failure through fatigue.
SUMMARY OF THE INVENTION
It is an object of the present invention to obviate or mitigate the aforesaid disadvantage by providing for a shock absorbing drive or lifting chain and/or a low cost chain.
According to a first aspect of the present invention there is provided a chain comprising a plurality of inner links each having at least one elongate pin, adjacent elongate pins of neighbouring inner links being connected together by an outer link portions, wherein there is sufficient spacing between an outer link portion and the corresponding inner links so as to permit flexing of the adjacent elongate pins in a direction substantially parallel to the length of the chain.
It is the capacity of the elongate pins to flex that advantageously provides the chain with a shock absorption capability when it is subject to harsh or sudden loads.
An outer link portion may be provided at each end of the adjacent elongate pins so as to form a closed loop.
The or each outer link portion, for example, may integral with each of the adjacent elongate pins. Alternatively, the or each outer link portion may be a separate link plate secured to ends of adjacent elongate pins, in which case the or each outer link plate is preferably secured to the elongate pin ends by means of an interference fit.
The elongate pins may each be fitted with a collar so that their lateral movement relative to the inner links is prevented. Such a collar is preferably an interference fit on the pin, however, it may take the form of a spacer extending along the length of the elongate pin between the inner link and the outer link portion.
Preferably the outer link portion is resiliently flexible in a direction parallel to the chain length. Each outer link portion may be in the form of a crimped plate, a crimped portion of which is resiliently extensible. A plurality of such outer link portions may be connected between adjacent elongate pins.
According to a second aspect of the invention there is provided a drive chain comprising a plurality of inner links each having at least one pin that is received in apertures in the inner links, adjacent pins of neighbouring inner links being connected together by an outer link portion, wherein the outer link portion is resiliently flexible in a direction along the length of the chain.
The outer link portion may, for example, be an oval shaped plate having an aperture, a U-shaped plate with adjacent pins being received in apertures in each limb of the U-shape or an S-shaped plate.
The S-shaped plate is preferably formed from spaced slots extending from opposed edges of the plate, the slots extending in a direction perpendicular to the length of the chain.
The oval shaped plate may a single central aperture or alternatively a plurality of apertures that may be in the form of diamond shaped cut-outs.
According to a third aspect of the present invention there is provided a drive chain comprising a plurality of inner links interconnected by connection links having parallel limbs that pass through apertures in the inner links and at least one integral portion interconnecting the limbs, wherein the connection links are open at one end to define a U-shape.
The connection link may be open at one end to define a U-shape or, alternatively may be closed at both ends to define a closed loop.


REFERENCES:
patent: 647046 (1900-04-01), Tessier
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patent: 2241820 (1941-05-01), Kohn
patent: 3535871 (1970-10-01), Jeffrey
patent: 3877688 (1975-04-01), McCarty
patent: 4041790 (1977-08-01), Paul
patent: 5176586 (1993-01-01), Sugimoto
patent: 5322483 (1994-06-01), Wang
patent: 5345753 (1994-09-01), Okuda et al.
patent: 6171209 (2001-01-01), Matsuda
patent: 295 14 700 U (1995-11-01), None
patent: 0 652 389 A (1995-05-01), None

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