Method for manufacturing a spring ring to be electroplated

A method for manufacturing a spring ring to be electroplated in subsequent processes wherein, on the occasion of assembling a movable core member to open and close a opening of a link body and a spring to push the said movable core member in a direction to close the said opening in a circular and tubular link body opened at one end and brazed with a ring on another, the spring is previously coated with a electrically non-conducting film by means of a coating treatment and then assembled into the said tubular link body.

The present invention relates to a method for manufacturing a spring ring 
to be electroplated in subsequent processes so that a movable core member 
provided therein can move smoothly after the spring ring is electroplated. 
Spring rings made of brass, for example, have hitherto been widely used as 
a connecting component of moderate price and good function for personal 
ornaments such as a necklace or the like. The spring rings made of brass 
are usually subjected to a electroplating process together with other 
component parts such as chains after the spring rings have been worked 
into necklaces or the like except in such specific cases as when they are 
used for such items as necklaces made of glass, plastic, or crystal beads 
strung in a row with a thread. In other words, the brass spring rings, the 
main object of this invention, are sometimes sold already electroplated 
but usually supplied to the manufacturers of necklaces or the like as 
component parts without electroplating. 
The conventional method for manufacturing a spring ring is brazing a ring 
to a circular, tubular link body with a opening at one end 1, assembling a 
movable core member 3 to open and close the opening of the said link body 
1 into the ring and providing in the ring a spring 4 to push the movable 
core member 3 in a direction to close the opening as shown in FIG. 1. The 
completed spring rings are then electroplated individually or after they 
have been further worked into necklaces or the like. 
Also, the spring ring is so arranged that the opening of the tubular link 
body 1 is opened by moving the movable core member 3 against the spring 4 
with a finger acting on a operating projection 5 of the movable core 
member 3 and is closed by returning the movable core member 3 with 
restoration of the spring 4 after release of the finger. 
However, in the conventional method for manufacturing the spring ring, the 
movable core member 3 has occasionally not been smoothly movable after 
being electroplated, particularly when the core member has been plated to 
a thickness exceeding 10 micron as in the case of bright nickel plating, 
thus raising a problem of producing defective products. 
The inventor of this invention had pursued the cause of the defective 
spring rings by encasing them into resin and cutting specimens which were 
ground and etched to be examined with a microscope. As a result of such 
microscopic observation, it was elucidated that some parts within the 
tubular link body 1, especially where the inside wall of the tubular link 
body 1 contacts the spring 4, were invaded with the plating solution to 
cause some metal deposit joining the spring 4 to the inside wall of the 
tubular link body 1, thereby obstructing the movable core member 3 from 
operating smoothly. 
Also, a quality examination was carried out on the spring rings in each 
step of the manufacturing processes, especially after the pre-plating and 
post-plating processes. As a result of this examination, it was also 
elucidated that during the pre-plating processes consisting of vapour and 
electrolytic degreasing, acid treatment and water rinsing, an oil kept 
inside of the spring ring body until then had been completely removed, 
thereby obstructing a smooth operation of the movable core member 3 and 
the spring 4. 
Furthermore, in the conventional method, when the spring 4 was oiled 
through the slit of the link body 1 and then the movable core member 3 
moved several times after electroplating, the movable core member 3 could 
be improved to some extent to move more smoothly. However, such effort of 
repairing every product for a large quantity after electroplating required 
tremendous labor thus raising the manufacturing cost. 
From this knowledge and expertise and by repeated experiments and 
researches, the inventor of this invention had confirmed the required 
effects of this invention to propose a spring ring of which the said core 
member can smoothly move even after being electroplated, by first coating 
the spring with a electrically non-conducting film by a coating treatment 
prior to assembly and thereafter assenbling the movable core member and 
the spring into the afore-said tubular link body to complete the spring 
ring. 
Although there might be possible a method of coating only the inside wall 
of the tubular link body with a electrically non-conducting film, it is 
extremely difficult to coat the electrically non-conducting film only on 
its inside wall due to the construction of the tubular link body. 
Moreover, such a electrically non-conducting film on the inside wall may 
obstruct electric conductivity of the core member in the subsequent 
plating processes because the core member should be plated too. Further, a 
coating in the link body may not be able to withstand the high temperature 
of brazing a ring 2 to the link body 1 even if the body could be coated 
before making the tubular link body.

DETAILED DESCRIPTION OF THE INVENTION 
The details and advantages of the invention will be apparent from the 
following description of a embodiment with the accompanying drawing. 
A circular and tubular link body 1 with a opening at one end is brazed with 
a ring 2 as shown in FIG. 1. Meanwhile, a spring 4 is immersed in a 
appropriate synthetic resin lacquer solution and subjected to a 
centrifugal drying so that the spring 4 is thinly and evenly coated with a 
electrically non-conducting film. 
It is preferable that the electrically non-conducting film be insoluble to 
solutions and solvents such as tri-chlorethylene used in the vapour 
degreasing or alkaline solutions used in the electrolytic degreasing 
process during the degreasing steps and hydrochloric acid or sulfuric acid 
used for acid pickling or activation, or the like of the pre-plating 
treatment, and plating baths; and also somewhat lubricative to the inner 
wall of the tubular link body 1. Since many synthetic resin or plastic 
lacquer films or wax films have such a property, an appropriate one can be 
selected from them. 
Then, the spring 4 coated with the electrically non-conducting film by 
means of the coating treatment and the movable core member 3 are assembled 
into the tubular link body 1 to complete a spring ring by the conventional 
way. Thus assembled spring rings or after further assembled spring rings 
into a necklace or the like normally are subjected to a bright nickel 
plating at first after the pre-plating processes such as degreasing, acid 
activating and the like, then to a ornamental plating such as gold, 
silver, rhodium or the like. 
The method of the present invention to manufacture a spring ring which 
should be electroplated afterwards prevents a metal deposit on the spring 
while electroplating by coating the said spring with the electrically 
non-conducting film by a way of coating treatment thus preventing the said 
spring from clinging to the inside wall of the tubular link body due to 
the metal deposit where they contact each other. This further allows the 
movable core member of the spring ring to smoothly operate even after 
electroplating due to the lubricative property of the afore-said 
electrically non-conducting film, without any essential and costly changes 
of the manufacturing process of the spring ring but only with a simple 
process added to attain the expected advantages proposing a considerable 
industrial benefit.