Method of making a catch for jewelry clasp

A catch for a jewelry clasp is disclosed which is formed from a single strip of dual thickness metal. A pushing member, having a second thickness which is preferably around three times the thickness of the first thickness portion of the tongue, is pressed to release the catch from a clasp to allow a wearer to remove an article of jewelry. Also disclosed is a method of making the catch where a dual thickness blank is formed by pressing a single thickness starting blank with a series of dies. A second method of making the catch is disclose where dual thickness blanks are cut from a ribbon of dual thickness metal stock.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention concerns clasps for jewelry of the type used for 
securing necklaces and bracelets to the wearer. More particularly, the 
invention relates to improved catches for use in jewelry clasps of the 
types mentioned above. 
2. Description of Background Invention 
Virtually all necklaces and bracelets are secured to the wearer by means of 
a clasp. A very popular clasp is described in U.S. Pat. No. 3,359,606. The 
male member, also known as the tongue or catch, for that clasp is stamped 
from a flat metal strip of uniform thickness, and therefore, the tongue 
itself is of uniform thickness throughout. 
The upright member of the tongue, which acts as a release for the clasp, is 
folded over on top to form a surface for pushing on to effect release of 
the tongue from its mating portion of the clasp. The folded portion 
projects substantially above the top of the assembled clasp and is 
necessary for facilitating an easy release of the clasp. 
Inherent problems exist with the folded upright tongue release. The 
significant projection of the tongue out of the clasp detracts 
significantly from the aesthetics of the clasp and the bracelet as a 
whole. Further, since the folded portion is open at the bottom, it may 
catch on fabric or on other jewelry. Still further, once constructed the 
upright projection must remain at the same height regardless of the height 
of the chain to which the clasp is attached, since the loop of the fold is 
at the top of the projection, and any attempt at shortening the projection 
would result in a bisection of the folded piece. Thus, the folded upright 
portion cannot be trimmed to blend with the attached chain. 
In an attempt to overcome the above-mentioned problems, a clasp has been 
devised wherein the folded over, upright portion of the tongue or catch 
has been replaced by a thick piece of metal which is soldered onto the 
remainder of the tongue. The result is a thickened portion of the tongue 
that sticks upright and forms a pushing surface by which the clasp can be 
released. This design eliminates the possibilities of the upright member 
of the tongue catching on fabric or other jewelry, and also this upright 
portion can be trimmed to match the height of the attached chain. This 
type of tongue has its own inherent problems, however. 
The attachment of the thickened upright member to the remaining portion of 
the tongue by soldering introduces excessive heat to the tongue portion 
thereby taking some of the temper out of the spring portion of the tongue. 
Thus, the tongue portion loses some of its elasticity and ability to latch 
the clasp effectively. Further, there is a possibility of the thickened 
member becoming detached from the tongue since the solder joint is more 
likely to break than an integral strip of metal, thereby making it 
impossible, or at least much more difficult to release the clasp and 
remove the item of jewelry. The solder joint may also fatigue or be 
defective from the outset. Still further, a tongue having a solder joint 
is aesthetically inferior to a tongue constructed from an integral strip 
of metal. 
SUMMARY OF THE INVENTION 
One advantage of the present invention is achieved by providing a catch for 
a jewelry clasp which is made from a dual thickness piece of metal, 
wherein a thicker upright portion is adapted to be pushed to release a 
thinner latching portion of the catch from the clasp. Since there is no 
requirement to solder the upright portion to the latching portion, none of 
the original temper or elasticity of the latching portion is lost and 
therefore the spring action of the latching portion is improved over that 
of the prior art. 
Another advantage of the present invention over the soldered prior art 
catch is that the possibility of the thick upright member coming apart 
from the latching portion is eliminated. Thus, the annoying situation of 
not being able to remove an article of jewelry because the clasp catch has 
lost its actuating member is avoided. 
Further, the catch of the present invention provides a comfortable, 
attractive pushing surface which is easily actuated to release the clasp, 
and can be trimmed to match the height of the attached chain. 
Accordingly, it is one object of the present invention to provide a catch 
having a latching portion of one thickness and an upright member which is 
thicker than the latching portion and provides a pushing surface for 
actuating the catch. The catch is formed from a single piece of metal 
which has a dual thickness. 
It is another object of the present invention to provide a method of 
forming a catch for a jewelry clasp wherein a starting blank is pressed to 
achieve a dual thickness within the blank, before the final blanking of 
the tongue shape. The intermediate or semi-blank is further pressed and 
blanked to the proper shape and is then bent to form a generally V-shaped 
latching portion attached to a thickened upright portion. The entire catch 
is formed from one integral piece of stock. 
It is a further object of the present invention to provide a method by 
which pairs of final blanks may be cut from a ribbon of dual thickness 
stock. The pairs of final blanks are then bisected and bent into final 
form so that each blank produces a generally V-shaped latching portion 
attached to a thickened upright portion. 
Other objects and advantages of the present invention and advantageous 
features thereof will become apparent as the description proceeds herein. 
Included in the description is a catch for a jewelry clasp including a dual 
thickness strip of metal wherein a portion of the strip has a first 
thickness and forms a latching portion and a portion of the strip has a 
second thickness and forms a pushing member for actuating the catch. The 
second thickness differs from the first thickness by an amount generally 
defined by the following equation: 
EQU T.delta.".SIGMA..sup.x .sub.n=1 (1/PDt.sub.n) 
wherein: 
T.sub.67 =the difference in thickness in inches; 
P=pressure in tons per square inch; 
D=a measure of ductility of the strip in inches per ton-second; 
t=time in seconds; 
n=index of current pressing step being carried out; and 
x=total number of pressing steps. 
The catch is formed from an integral strip of dual thickness metal. The 
second thickness is greater than the first thickness, generally by 1.5 to 
5 times, more particularly by 2 to 4 times and most preferably by around 3 
times. 
The first thickness portion of the strip is bent backwardly upon itself in 
a substantial V-shape to form the latching portion of the catch. The 
latching portion has an upper member and a lower member and the pushing 
member of the catch is substantially perpendicular to the upper member and 
is integral with the upper member. 
The lower member of the latching portion is bent at a substantially right 
angle to provide an end portion and the upper member is integral with the 
pushing member, which is the thickened portion of the integral strip. The 
upper member is recessed adjacent the pushing member to form a locking 
portion. The catch optionally may further include means for joining a 
safety lock with the catch. The means for joining is attached to the end 
portion of the catch and is preferably a cylindrical member which is 
formed from a piece of metal tubing. 
The catch is further disclosed as being formed from an integral dual 
thickness strip of metal. 
One method of making a dual thickness catch for a clasp is disclosed to 
include: stamping a wire or flat metal strip having uniform thickness to 
form a starting blank; forming a semi-blank by pressing the starting blank 
to achieve a dual thickness within the semi-blank; forming a final blank 
comprising recesses in the strip at a location adjacent the boundary of 
the two different thicknesses; and bending the final blank to form a 
substantially V-shaped tongue having a first thickness and a substantially 
upright pushing member which has a second thickness which is greater than 
the first thickness. 
This method uses pressing steps with pressures which are generally defined 
by the following empirically derived equation: 
EQU T.delta.=.SIGMA..sup.x .sub.n=1 (1/PDt.sub.n) 
wherein: 
T.sub..delta. =said difference in thickness in inches; 
P=pressure in tons per square inch; 
D=a measure of ductility of said blank in inches per ton-second; 
t=time in seconds; 
n=index of current pressing step being carried out; and 
x=total number of pressing steps. 
Further according to the first method mentioned above, the starting blank 
is substantially rectangular, is placed in a die and pressed to form the 
semi-blank, which is substantially spoon-shaped. The semi-blank is then 
pressed to substantially flatten the semi-blank to form an approximate 
final blank. The approximate final blank is next cut to form a final blank 
having a precise shape for bending into a catch. An annealing step may be 
carried out after each pressing step. 
The method produces a catch having a second thickness which is about 1.5 to 
5 times greater than the first thickness, preferably about 2 to 4 times 
greater than the first thickness, and most preferably around three times 
greater than the first thickness. 
A second method of making a dual thickness catch for a clasp is disclosed 
as including: cutting a strip of material from a sheet of stock material 
which has a first thickness portion and a second thickness portion to 
obtain a dual thickness strip; cutting the dual thickness strip 
substantially perpendicularly to the first cut to form two dual thickness 
strips of substantially equal proportions; bending the first thickness 
portion of each strip to form a substantially V-shaped tongue wherein the 
portion of the metal strip having the second thickness is integral with 
one end of the V-shape; bending the second thickness portion to form a 
pushing member, wherein the pushing member is substantially perpendicular 
to the tongue portion. 
The second thickness portion is thicker than the first thickness portion, 
generally by 1.5 to 5 times, more particularly by 2 to 4 times and most 
preferably by around 3 times. 
Also disclosed is a jewelry clasp including the catch described above, 
having a dual thickness strip of metal wherein a portion of the strip 
having a first thickness forms a latching portion and a portion of the 
strip having a second thickness forms a pushing member for actuating the 
catch; and a keeper which mates with the catch to secure the clasp. 
Further disclosed is an article of jewelry which includes a catch according 
to the present invention, made from a dual thickness strip of metal 
wherein a portion of the strip having a first thickness .forms a latching 
portion and a portion of the strip having a second thickness forms a 
pushing member for actuating the catch. A keeper which mates with the 
catch enables securement of the article of jewelry. The article of jewelry 
further includes means for ornamenting a wearer, such as a chain, which is 
attached to the keeper and the catch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings in detail, FIG. 1 shows a plan view of a 
completed catch according to the present invention. Catch 1 is formed from 
a single strip of dual thickness metal. The first thickness portion of the 
strip is bent as shown as bend 4 to form a substantially V-shaped 
resilient, latching portion or tongue which is adapted to be inserted into 
a keeper or female portion of a clasp. The V-shaped latching portion is 
comprised of a generally elongated overlying latching portion 3 and a 
generally elongated underlying portion 2. As will be explained below, the 
overlying latching portion includes a pair of oppositely positioned 
locking recesses 6 for engagement with a mating keeper. 
Lower portion 2 is bent at the end opposite the V-bend of the latching 
portion, to form end member 5 having a first thickness. End 5 is wider 
than lower portion 2, so as to generally match the width of the keeper 
that fits over the latching portion. End 5 is substantially perpendicular 
to lower portion 2. 
Upper portion 3 is unitary with a second thickness portion of the metal 
strip at the end of upper portion 3 which is opposite the V-bend of the 
latching portion. The metal strip is bent at a substantial right angle at 
the juncture of the first and second thicknesses to form a thick upright 
member 8 at the end of upper portion 3. Thick upright member 8 is also 
referred to as push bar 8 or pushing member 8. Push bar 8 is of a second 
thickness which is greater than the above-identified first thickness which 
characterizes the remainder of the catch. The additional thickness of push 
bar 8 makes the end more easily accessible and more comfortable for the 
user to operate, i.e., the user pushes on the end of push bar 8 to release 
the catch from the keeper and thereby open the clasp. The thickness of 
push bar member is generally 1.5 to 5 times greater than the first 
thickness of the catch, more preferably 2 to 4 times greater, and most 
preferably about three times greater. 
Adjacent the right angle bend between upright member 8 and upper latching 
portion 3, upper latching portion 3 has a pair of recesses 6 which lock 
catch 1 into a keeper until upright member 8 is pushed to release the 
latch. 
Upper latching portion 3 is slightly bent at 7 away from lower latching 
portion 2 to create greater travel and spring force between the upper and 
lower latching portions. 
FIGS. 2A-2C show side, top and end views respectively. Bend 7, as described 
previously, is more readily apparent in the view shown in FIG. 2A. End 5 
is reinforced by gusset 10, as shown in FIGS. 2B and 2C and which 
protrudes through the joint between lower member 2 and end 5 at 11 as 
shown in FIG. 2A. Gusset 10 is disclosed in more detail in U.S. Pat. No. 
4,697,315, which was incorporated by reference above. 
Catch 1 may optionally include cylindrical member 9 which serves as a hinge 
for a figure-eight safety lock for the clasp. Cylinder 9 is preferably 
soldered to end member 5 and is preferably formed from a piece of round 
metal tubing. 
FIG. 3 is a plan view of the prior art and shows that the push bar 40 is 
soldered to the latching portion 41 of the catch. The inherent problems 
with this type of catch that the present invention overcomes, as discussed 
previously, are that soldering the push bar to the latching portion takes 
some or all of the temper out of the latching portion thereby causing it 
to lose some or all of its resiliency and possibly also causing it to 
become brittle. Further, there is always the possibility of the push bar 
of the prior art device becoming detached from the latching member, 
thereby making it difficult if not impossible to actuate and release the 
clasp. 
FIGS. 4A-4C are side, top and end views of flat metal strip 20 which is 
substantially rectangular and has substantially uniform length, width and 
thickness. Flat strip 20 is used as a starting blank in the first method 
of producing the catch of the present invention. Flat strip 20 may be 
stamped from a continuous roll of flat metal strip or is stamped and 
pressed from a roll of metal wire or stamped from any other convenient 
source of stock. Flat metal strip 20 is next placed in a die (not shown) 
and pressed to form a semi-blank as shown in FIGS. 5A-5C. 
Semi-blank 21 roughly takes on the shape of a spoon, wherein the first 
thickness 22 which results from the pressing operation is not uniform in 
thickness, but thinner in the middle 24 as shown in FIGS. 5A and 5C. A 
second thickness 23 is equal to the thickness of starting blank 20 and is 
the thickness of the unpressed potion of the semi-blank. A bevel in the 
die forms the bevelled transition area 25 between the first and second 
thicknesses of the semi-blank. The bevel serves to reinforce the juncture 
between the two thicknesses as well as to provide a smooth transition 
between the two. The semi-blank, after pressing may optionally be 
annealed. 
Semi-blank 21 is next placed into another die (not shown) having a slightly 
greater width than the first die. The spoon shape of the semi-blank is 
pressed flat to form an approximate final blank 31 as shown in FIGS. 
6A-6C. The first thickness portion 32 of the approximate final blank has a 
substantially consistent thickness throughout. Unpressed portion 33 has a 
second thickness throughout, which is substantially equal to the thickness 
of the portion 23 of the semi-blank as well as the thickness of the 
starting blank. Bevel 35 forms an angle with the unpressed portion 33 of 
approximately 40 to 45 degrees, which is substantially to the bevel angle 
formed between bevel 25 and the unpressed portion of the semi-blank 23. 
The approximate final blank 31 may optionally be annealed before 
proceeding to the next method . step. 
Approximate final blank is next "blanked out" or cut to the exact 
dimensions desired so that the final blank can be bent into a finished 
product, i.e. the final shape of the catch is cut out from the approximate 
final blank. The final blank is then bent as described above with 
reference to FIG. 1 to form a catch. It is repeated here for emphasis, 
that no soldering whatsoever is required to form the catch and therefore 
the spring force of the tongue is not diminished, nor does the tongue 
become brittle. 
The above method uses pressing steps with pressures which are generally 
defined by the following empirically derived equation: 
EQU T.delta.=.SIGMA..sup.x .sub.n=1 (1/PDt.sub.n) 
wherein: 
T.sub..delta. =said difference in thickness in inches; 
P=pressure in tons per square inch; 
D=a measure of ductility of said blank in inches per ton 
second; 
t=time in seconds; 
n=index of current pressing step being carried out; and 
x=total number of pressing steps. 
The method produces a catch having a second thickness which is about 1.5 to 
5 times greater than the first thickness, preferably about 2 to 4 times 
greater than the first thickness, and most preferably around three times 
greater than the first thickness. 
A second method of making a dual thickness catch for a clasp may be 
employed which includes cutting a strip of material from a sheet of stock 
material which has a first thickness portion and a second thickness 
portion to obtain a dual thickness strip. A ribbon of dual thickness stock 
material is depicted in FIG. 7A. A break in the figure at 61 indicates 
that dual thickness ribbons may be available in rolls or very long strips. 
Ribbon 60 includes first thickness portions 62 and second thickness 
portion 63 which are unitary with the first thickness portions. Bevelled 
areas 65 are located in the transition areas between first and second 
thicknesses. The bevels form approximately 40-45 degree angles with the 
second thickness surface 63, as shown in FIG. 7B. 
A dual thickness strip having a width equal to the desired width of the 
catch to be produced is cut from the end of the ribbon to thereby provide 
a double blank, i.e., a blank having a pair of oppositely positioned first 
thickness parts 63 and a single second thickness part 62 therebetween. A 
second cut, which is substantially perpendicular to the first cut is made 
across the middle of the second thickness part 63 of the double blank to 
form two dual thickness strips or blanks of substantially equal 
proportions. The two substantially equal strips are final blanks which can 
be bent into catches, as described above with reference to FIG. 1. 
The first thickness portion of each strip is bent to form a substantially 
V-shaped tongue wherein the portion of the metal strip having the second 
thickness is integral with one end of the V-shape. The second thickness 
portion is bent relative to the first thickness portion to form a pushing 
member, wherein the pushing member is substantially perpendicular to the 
tongue portion. 
The second thickness portion is thicker than the first thickness portion, 
generally by 1.5 to 5 times, more particularly by 2 to 4 times and most 
preferably by around 3 times. 
FIG. 8 shows an embodiment of an article of jewelry which is cut away at 
110 and 120. Chain 90 is attached to keeper 100 and catch 1. Catch 1 is 
adapted to mate with keeper 100 to form a clasp which secures the article 
of jewelry to the wearer. The catch and keeper are not limited to use with 
a chain, but may be attached to a band, strap, or other ornamental article 
which may be worn as an article of jewelry. 
The following is an example of forming a catch by the first method, 
described above. This example is in no way meant to limit the invention or 
disclosure, since many different sizes of catches can be and are produced 
by this method and since all of those sizes can also be produced by the 
other methods: 
A starting blank of dimensions 0.675.times.0.130.times.0.036 inches is 
stamped from a roll of strip metal stock. The blank is then placed in a 
first die and a pressure of 25 tons/in.sup.2 is applied to the blank for 
about 2 seconds. A semi-blank is removed from the die. The unpressed 
second thickness portion has a length of about 0.100 inches. The bevelled 
transition area 25 extends about 0.025 inches along the length of the 
semi-blank. The "spoon-shaped" portion of the semi-blank has a width of 
about 0.300 inches and a length of about 0.550 inches. The first thickness 
of the "spoon-shaped" portion is about 0.024 inches, while the thinner 
central region has a thickness of about 0.012 inches. 
The semi-blank is next placed into a slightly wider die and pressed again 
with the same amount of pressure for about two seconds. The resultant 
approximate final blank has the same dimensions as the semi-blank except 
the width of the first thickness portion 32 is about 0.350 inches and the 
first thickness portion is about 0.012 inches thick throughout. The 
approximate final blank can next be cut to the exact final shape and 
dimensions of the catch and bent to into the final shape of the catch as 
described previously. 
Finally, the following is a summary of forming a catch by the second 
method, described above. A strip of material is cut from stock material 
having at least a first thickness portion 62 and a second, greater 
thickness portion 63 to thereby form a substantially flat blank. Before 
bending portions of the blank, cuts are made to form, e.g., the recesses 6 
and the greater width end member 5. Then the first thickness part 62 of 
the blank is bent intermediate of a first end of the blank and a 
transition area between the first thickness part and the second thickness 
part to form a bend 4, thereby creating a V-shaped tongue. The tongue has 
an overlying latching portion 3 and an underlying portion 2, the overlying 
portion extending in a direction from the bend 4 toward the second 
thickness part 63 and the underlying portion extending in a direction from 
the bend 4 toward the portion later to be bent into end member 5. Next, in 
an area of the transition between the first thickness part and the second 
thickness part, the blank is bent to form a pushing member 8 from the 
second thickness part 63, extending away from the first thickness part 62 
and, more particularly, away from the underlying part 2 thereof. 
Although the invention has been described with reference to particular 
means, materials and embodiments, it is to be understood that the 
invention is not limited to the particulars disclosed and extends to all 
equivalents within the scope of the claims.