Chain – staple – and horseshoe making – Chain making – Blanks and processes
Reexamination Certificate
2000-09-28
2002-08-06
Jones, David (Department: 3725)
Chain, staple, and horseshoe making
Chain making
Blanks and processes
C059S029000, C059S901000, C474S215000, C474S216000, C474S217000
Reexamination Certificate
active
06427433
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rocker joint pin for used in a chain to articulately interconnect link plates of the chain, and a method of and an apparatus for producing the rocker joint pin.
2. Description of the Related Art
A chain is constituted by a large number of link plates articulately connected together in an endless fashion by means of connecting pins. The connecting pins are generally classified into two types, one being a round pivot pin and the other being a rocker joint pin. The rocker joint pin is used in many case for silent chains and also for chain belts of continuous variable transmissions (CVTs).
Conventionally, in the manufacture of a connecting pin, a continuous wire drawn in a cross-sectional shape substantially the same as that of a finished connecting pin is cut off or severed into pin stocks of product length. The pin stocks are then subjected to chamfering to form a beveled edge at both longitudinal end faces of each individual pin stock. The chamfering is effected to ensure that the connecting pins can be smoothly inserted into pin-accommodating holes in the link plates during the process of assembling the chain. The chamfered pin stocks are heat treated and then finished into a final shape of the pins.
In the case of the round pivot pin, chamfering is generally achieved by way of barrel finishing (tumbling) or pin-heading (forging). In the case of the rocker joint pins, chamfering is generally achieved by way of barrel finishing. A pin-heading (forging) operation or a cutting operation is used sometimes.
The barrel finishing operation used for chamfering the rocker joint pins is disadvantageous due to a difficulty in forming a sufficiently large chamfered or beveled edge. An attempt to produce a sufficiently large beveled edge by the barrel finishing requires a considerably long processing time, tending to cause undesired removal of material from a different part of the rocker joint pin, such as a convexly arcuate surface. The thus finished rocker joint pin no longer possesses the original cross-sectional shape.
The pin-heading (forging) process used for chamfering the rocker joint pins is also disadvantageous in that, due to a change in the cross-sectional shape of the rocker joint pin, an accurate pin-heading operation is difficult to achieve.
In the case where the pin-heading (forging) operation or the cutting operation is carried out to chamfer the rocker joint pins of a product length, a parts feeder or the like orienting machine must be provided to arrange the individual rocker joint pins into a desired orientation before the pins are processed or chamfered by a pin-heading machine or a cutting machine. This requirement increases the equipment cost, leading to an increase in the manufacturing cost of the rocker joint pins.
SUMMARY OF THE INVENTION
It is, accordingly, a general object of the present invention to overcome the problems associated with the conventonal chamfering processes used for forming a beveled edge at both longitudinal end faces of a rocker joint pin.
A more specific object of the present invention is to provide a rocker joint pin for chains, which can be manufactured at a relatively low cost and smoothly assembled with link plates of a chain.
Another object of the present invention is to provide a method which is capable of economically producing a rocker joint pin having a sufficiently large beveled edge at opposite end faces of the pin.
A further object of the present invention is to provide an apparatus for reducing the method into practice.
A still further object of the present invention is to provide a rocker joint pin produced by the foregoing method.
According to one aspect of the present invention, there is provided a rocker joint pin for use in a chain to articulately interconnect link plates of the chain, the rocker joint pin having a beveled edge formed at opposite end faces thereof, the beveled edge having been subjected to grooving to form a V-shaped groove transversely across a surface of a continuous wire, and the end faces having been subjected to cutting to sever the wire at the bottom of the V-shaped groove.
According to another aspect of the present invention, there is provided a method of producing a rocker joint pin for a chain, the pin having a beveled edge at opposite end faces thereof, the method comprising the steps of: intermittently feeding a continuous wire longitudinally along a path; forming a V-shaped groove transversely across a surface of the wire while the wire is at rest; and cutting the wire at the bottom of the V-shaped groove while the wire is at rest, thereby producing a rocker joint pin having a beveled edge at opposite end faces thereof.
The forming step may be achieved either by reciprocating a groove forming punch in a direction perpendicular to the path, or alternatively by reciprocating a cutting tool in a direction orthogonal to the path. The groove forming punch and the cutting tool have a V-shaped cutting edge.
According to still another aspect of the present invention, there is provided an apparatus for producing a rocker joint pin for a chain, the rocker joint pin having a beveled edge at opposite end faces thereof, the apparatus comprising: a feed unit for intermittently feeding a continuous wire longitudinally along a path; a grooving unit disposed downstream of the feed unit for forming a V-shaped groove transversely across a surface of the wire while the wire is at rest; and a cutting unit disposed downstream of the grooving unit for severing the wire at the bottom of the V-shaped groove while the wire is at rest, thereby producing a rocker joint pin having a beveled edge at opposite end faces thereof.
The apparatus may further comprise a positioning unit disposed downstream of the cutting unit for positioning a leading end of the wire.
In one preferred form, the grooving unit comprises a fixed die disposed on one side of the path for supporting one surface of the wire, and a movable grooving punch disposed on the opposite side of the path and reciprocally movable toward and away from the fixed die for forming the V-shaped groove on the opposite surface of the wire, the grooving punch having a V-shaped cutting edge. Preferably, the fixed die has a guide surface so profiled as to comport with a profile of the one surface of the wire, and the cutting edge of the movable grooving punch has a profile complementary in shape to a profile of the opposite surface of the wire.
As a first alternative, the grooving unit may comprise a cooperating pair of aligned, movable grooving punches disposed on opposite sides of the path and reciprocally movable toward and away from each other for forming the V-shaped groove on opposite surfaces of the wire, the grooving punches having a V-shaped cutting edge. It is preferable that the cutting edge of one of the pair of movable grooving punches has a profile complementary in shape to a profile of one of the opposite surfaces of the wire, and the cutting edge of the other of the pair of movable grooving punches has a profile complementary in shape to a profile of the other of the opposite surfaces of the wire.
As a second alterative, the grooving unit may comprise a cutting tool disposed on one side of the path and movable transversely across the path for forming the V-shaped groove on one surface of the wire, the cutting tool having a V-shaped cutting edge. The grooving unit may further comprise a second cutting tool disposed in alignment with the cutting tool and movable transversely across the path for forming the V-shaped groove on the opposite surface of the wire, the second cutting tool having a V-shaped cutting edge.
In one preferred form, the cutting unit comprises a fixed cutting die having a guide hole aligned with the path for the passage therethrough of the wire, and a movable cutting die having a guide hole normally disposed in alignment with the path for the passage therethrough of the wire. The movable cutting die is movable relative to the fixed die between a first posit
Kubota Seiichi
Takagishi Yoshiaki
Howson & Howson
Jones David
Tsubakimoto Chain Co.
LandOfFree
Rocker joint pin for chain, and method and apparatus for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rocker joint pin for chain, and method and apparatus for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rocker joint pin for chain, and method and apparatus for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2911853