BACKGROUND OF THE INVENTION
This invention relates generally to the field of clasp mechanisms used to join or close upon themselves chains, ropes or other articles. More particularly, the invention is directed to the field of such clasps used with jewelry chains, bracelets, necklaces, etc.
Clasps used in the jewelry field to join the ends of bracelets and necklaces are of necessity very small so that the clasp mechanism will not detract from the ornamentation of the piece. Such clasps must also be very secure since the jewelry can be very valuable. It is therefore desirable to have clasps which are designed and constructed to be effective against accidental opening, as well as to be easily workable by the user. It is also preferable that the clasp have some artistic merit to it as well. The mechanisms should also be of relatively simple construction.
Typical jewelry clasps operate with spring rings which require the user to slidingly move a curved pin contained within a tubular body to open and close the device. Because the clasp is of such small size, it is very difficult to operate this type of clasp. The user must balance and secure the main body portion while using a fingernail to slide back the mechanism. Other clasps, such as shown in U.S. Pat. No. 2,874,435 to Nielsen and U.S. Pat. No. 3,956,804 to Gatof et al., are constructed with closing pincers which must also be pried or pulled open. These clasps suffer from the same drawbacks.
It is an object of this invention to provide a clasp of small size which is relatively simple mechanically, secure and easily operable.
It is an additional object of the invention to provide a clasp which is operable by a simple squeezing motion between thumb and forefinger, eliminating the need to pull or pry on any particular parts of the device.
BRIEF SUMMARY OF THE INVENTION
The clasp comprises a main body portion, a keeper arm, and a spring member, where the keeper arm is pivotally attached to the main body portion at relatively central points longitudinally of each component so that the two components are moveable relative to each other in a scissor-like manner. The keeper arm is comprised of a mating end, an actuating shoulder, a spring cavity and pivot pin receiving means. The main body is comprised of a hook end, an arm cavity, an arm aperture, and a shoulder aperture. A linkage attachment means, comprising an aperture, loop or the like, is positioned at the end of the main body opposite from the hook end for permanent attachment of the object being joined.
The keeper arm is positioned within the arm cavity of the main body such that the mating end of the keeper arm extends through the arm aperture and meets or corresponds to the hook end. The actuating shoulder of the keeper arm extends from the shoulder aperture of the main body. A pivot pin or like means links the two elements, the pivot pin extending through arm cavity of the main body into the pivot pin receiving means of the keeper arm. The coiled spring in the spring cavity surrounds the pivot pin and the ends of the coiled spring abut portions of the spring cavity and arm cavity so as to maintain the device in the closed position until pressure is applied.
To operate the device, the user grasps the clasp so that the thumb and forefinger rest against the main body and the actuating shoulder part of the keeper arm. Squeezing the main body and the actuating shoulder causes compression of the spring and the actuating shoulder moves into the shoulder cavity of the main body. Because of the centralized pivot, this action causes the mating end of the keeper arm to move inwardly away from the hood end, creating an opening and allowing the hook end to be inserted onto a loop end of a chain, bracelet or necklace. Release of the pressure against the actuating shoulder allows the coiled spring to return the mating end of the keeper arm back into conjunction with the hook arm, closing off the opening and enclosing the loop end securely within the interior portion of the hook end. The pressure of the coiled spring maintains the clasp in this closed position until the device is opened by the user for removal of the loop end.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a side view of the invention in the closed position.
FIG. 2 is a top view of the invention.
FIG. 3 is a bottom view of the invention.
FIG. 4 is a side view of the invention in the open position.
FIG. 5 is a cross-sectional view of the main body portion of the invention taken along line V—V of FIG. 1, showing the keeper arm and spring as exposed.
DETAILED DESCRIPTION OF THE INVENTION
With reference now to the figures, the invention will be described in view of the best mode and preferred embodiment. In general, the invention comprises a
main body 10, a
keeper arm 20, and a
coiled spring 30.
Referring to FIG. 1, the relationship of the
main body 10 and the
keeper arm 20 is shown. The
main body 10 comprises a
hook end 11 and linkage attachment means
15 positioned at opposite ends of the
main body 10. Linkage attachment means
15 is used for connecting the clasp to one end of the chain or article which requires joining, and can be an aperture (as shown) for receiving a chain link, a loop extending from the
main body 10, or any other typical structure known in the art for accomplishing this attachment. This attachment will usually be a permanent attachment. Extending through the
main body 10 is the
keeper arm 20.
Keeper arm 20 comprises a
mating end 21 and an actuating
shoulder 22. Mating
end 21 acts in conjunction with
hook end 11 of the
main body 10 to form a closed
interior space 99. Mating
end 21 should preferably match the configuration of the
hook end 11 at the conjunction point and should abut
hook end 11 such that no or only minimal space separates the two components.
As seen in FIG. 3, the actuating
shoulder 22 of
keeper arm 20 extends out of
main body 10 through a
shoulder aperture 14.
Shoulder aperture 14 is a slot which opens into the
arm cavity 12 of
main body 10.
Referring now to FIG. 5, the
main body 10 is shown in cross-section to expose the other components of the invention.
Keeper arm 20 is positioned within
arm cavity 12 of
main body 10.
Arm cavity 12 is an interior space of sufficient size to allow the keeper arm
20 a range of motion when pivoted around
pivot pin 40. The
mating end 21 extends through
arm aperture 13 of
main body 10 and the actuating
shoulder 22 of
keeper arm 20 extends out from
shoulder aperture 14 of
main body 10.
Pivot pin 40 extends transversely through
arm cavity 12.
Pivot pin 40 can be attached to the interior wall of
main body 10 or can be inserted through apertures cut into the sides of
main body 10, the
pivot pin 40 being soldered to secure it to the
main body 10. Pivot pin receiving means
24 of
keeper arm 20, preferably a tubular aperture, allows
keeper arm 20 to rotate on
pivot pin 40 relative to
main body 10. Pivot pin receiving means
24 is preferably positioned to one side of the longitudinal axis as shown. This positioning allows for a greater separation distance between the
mating end 21 and the
hook end 11 when the clasp is opened. The size of the
arm aperture 13 and overall configuration of the
arm cavity 12 controls the extent of movement for
keeper arm 20.
Coiled
spring 30 is seated in a
spring cavity 23 on
keeper arm 20 and surrounds the
pivot pin 40 and pivot
pin receiving means 24. Coiled
spring 30 has an extended
long arm 31 and an extended
short arm 32.
Short arm 32 rests in a
slot 33 or abuts the side of
keeper arm 20 while
long arm 31 abuts against the side of
arm cavity 12 in the
main body 10. In this manner, the compression within the
coiled spring 30 will maintain the
keeper arm 20 in the closed position with the
mating end 21 abutting the
hook end 11 of the
main body 10 and the actuating
shoulder 22 extending the maximum distance from the
shoulder aperture 14. Movement of the actuating
shoulder 22 into the
arm cavity 12 of the
main body 10 will compress the
spring 30, causing the
mating end 21 to move into the
interior space 99 of
hook end 11, as shown in FIG.
4. Release of pressure against the
spring 30 causes the
mating end 21 to realign with the
hook end 11, effectively closing off the
interior space 99 and preventing any chain loop inserted over hook end
11 from coming free.
While the invention is shown with a particular design for its outer configuration, it should be apparent that other designs are possible which allow the mechanism to operate in the manner as described. The rounded configuration is preferred for ease of manipulation, but is not required. The
actuating shoulder 22 and portions of the
main body 10 could be scored to create a better gripping surface. Springs of different configuration and positioning can be used in place of coiled
spring 30 to maintain the clasp in the closed position. For example, a folded leaf spring could be inserted into the
arm cavity 12 to abut the inside of the
actuating shoulder 22 of
keeper arm 20 and the inside wall of
arm cavity 12.
The full scope and definition of the invention therefore, is to be as set forth in the following claims.