Apparatus for closing wrist straps
First Claim
1. A strap closure apparatus for wrist straps, in particular straps of wrist watches, said apparatus having a magnetic closure and an automatic mechanical lock for two closure parts and comprising at least one permanent magnet for providing magnetic force and a yoke forming part of a magnetic circuit, and a shield (6) comprising ferromagnetic material of comparatively high permeability substantially enclosing said magnetic circuit and being magnetically isolated from said magnetic circuit by air gaps (22, 23) and elements (14) whose permeability is lower than the permeability of the shield.
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Accused Products
Abstract
A strap closure for straps of wrist watches comprises a magnetic closure and an automatic mechanical lock. The closure comprises two closure parts (1, 2) and at least one permanent magnet (16) and a yoke (9), which form parts of a magnetic circuit. Said magnetic circuit is disposed inside a shield (6) made of a ferromagnetic material and closed as far as possible on all sides. Between the magnetic circuit (9, 15, 16) and said shield or other closure parts there is no metallic contact whatsoever with elements of high permeability, the magnetic circuit is instead isolated from the shield or from other closure parts by air gaps (22, 23) and fastening elements (14) of a low permeability close to the value of air.
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Citations
19 Claims
- 1. A strap closure apparatus for wrist straps, in particular straps of wrist watches, said apparatus having a magnetic closure and an automatic mechanical lock for two closure parts and comprising at least one permanent magnet for providing magnetic force and a yoke forming part of a magnetic circuit, and a shield (6) comprising ferromagnetic material of comparatively high permeability substantially enclosing said magnetic circuit and being magnetically isolated from said magnetic circuit by air gaps (22, 23) and elements (14) whose permeability is lower than the permeability of the shield.
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7. A strap closure for straps of wrist watches, comprising a first closure part adapted to be fixed to an end of one strap and a second closure part adapted to be fixed to an end of another strap for cooperation with said first closure part to connect together said ends of said straps;
- said first closure part including a permanent magnet and shielding material of high magnetic permeability surrounding said permanent magnet except for a narrow slot in said shielding material and being spaced from and magnetically unconnected to said permanent magnet; and
said second closure part including an element of magnetic material shaped for movement into said slot to complete a magnetic circuit induced by said permanent magnet. - View Dependent Claims (8, 9, 10)
- said first closure part including a permanent magnet and shielding material of high magnetic permeability surrounding said permanent magnet except for a narrow slot in said shielding material and being spaced from and magnetically unconnected to said permanent magnet; and
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11. A strap closure comprising a first closure part adapted to be fixed to an end of one strap and a second closure part adapted to be fixed to an end of another strap for overlying and cooperating with said first closure part to connect together said ends of said straps;
- said first closure part including
permanent magnet means, a shield in the form of a box substantially surrounding said permanent magnet means and comprising ferromagnetic material of high permeability, said box having first and second end portions and a top wall with a slot therein at said first end portion, and means for mounting said permanent magnet means inside said second end portion of said box and magnetically isolating said shield from said permanent magnet means, and said second closure part including an element comprising magnetic material adapted for movement through said slot into a position inside said box and spaced from said shield to complete within said shield a magnetic circuit induced by said permanent magnet means. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
- said first closure part including
Specification