Spectacle frame

Abstract: A spectacle frame is characterized in that a shape memory alloy (111) is used as a constituent material of face-contacting portions such as sides (1; 101) and lens-fixing portions such as a rim (2), a β-phase titanium alloy is used as a constituent material of connecting members (12, 13) for connecting the face-­ contacting portions and the lens-fixing portions, and the members are soldered with a palladium-based sol­ dering material.

Description: Background of the invention: The present invention relates to a spectacle frame according to the preamble of claim 1. A spectacle frame of this type is disclosed in the JP-A-63271315 wherein a shape memory alloy material (hereafter referred to as a NT alloy material) is used as the major members, i. e. the pad arms, the lug, the bridge and the sides, and a nickel-chromium alloy (hereafter referred to as a NiCr alloy) is used for portions (connecting members) which require machining. Furthermore, such members are soldered with a palladium-based soldering material (hereafter referred to as a Pd material). Although such a conventional spectacle frame has had generally acceptable characteristics, there have been drawbacks in that the soldering material fails to flow smoothly in the soldering process and that it is not well suited to plating. In Patent abstracts of Japan, Vol. 10, No. 202 (P477) (2258) & JP-A-61043717 is disclosed that to produce a glasses frame where soldering is made easy and the required soldering strength is secured, a composite billet produced with a metal consisting essentially of titanium is subjected to β-treatment. DE-A1-3734056 discloses several types of titanium alloys which are suitable for being machined and for being soldered, and which are provided for spectacle frames. Summary of the Invention Accordingly, an object of the present invention is to provide a spectacle frame which is sturdy, fits comfortably with the user's head portion to which the spectacle frame is applied, overcomes the faulty flow of solder, allows plating to be effected positively, does not require an undue force in the fitting of a lens, and has a unique texture by using a titanium alloy, instead of a NiCr alloy which has been conventionally used for portions requiring machining. To attain the above-described objects, in accordance with the present invention, there is provided a spectacle frame as specified in the preamble of claim 1 which is characterized in the the rims are formed of shape memory alloy and in that the joint and the brow lug are made from a β-phase titanium alloy. Furthermore, a silver-palladium alloy is suitable as a palladium-based soldering material. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings. Brief description of the drawings Fig. 1 is a perspective view of a part of a spectacle frame in which parts are soldered by using a soldering material in accordance with the present invention; Fig. 2 is a diagram illustrating the characteristics of component parts of the spectacle frame used in a combination; Fig. 3 is a diagram illustrating the soldering strength of various members; Fig. 4 is a diagram illustrating a mode of a sample test. Description of the preferred embodiment Fig. 1 is a perspective view of a part of a spectacle frame in accordance with the present invention. A side 1 is connected to a lug 3 via a joint 12, and the lug 3 is connected to a rim 2, which serves as a lens fixing member, via a brow lug 13. The rim 2 is connected to the other rim (not shown) via a bridge 5. In addition, the rim 2 is provided with a pad arm 4 connected with a stud case 11. These members are secured by soldering, and portions requiring soldering are denoted by reference numeral 21. In addition, the side 1, the rim 2, the lug 3, the pad arm 4, and the bridge 5 are respectively formed of an NT alloy material formed in such a manner as to retain an optimum configuration at normal temperature. The stud case 11, a joint 12, and the brow lug 13 are provided with precision machining including cutting, boring, and tapping. In accordance with the present invention, a Ti alloy, preferably, β-phase Ti alloy, was used for connecting members which require precision machining, such as the lug 13, the joint 12, and the stud case 11. In addition, a Pd-based soldering material is used for soldering portions. As a Pd-based soldering material, for instance, a silver-palladium alloy (Ag-Pd alloy) is suitably used. Figs. 2 to 4 illustrating the characteristics of the spectacle frame in accordance with the present invention. Fig. 2 shows, in the form of a table, the characteristics of the component parts of the spectacle frame that are used in combination. In the table shown in Fig. 2, the respective parts A are subjected to various machining processes shown in column B, and the possible use of an NT alloy is shown in column C. In addition, column D in the table shows soldering can be performed between the members concerned and shows combinations of usable soldering materials. Fig. 3 is a diagram illustrating the soldering strength of the members used in the present invention and those used in the prior art. In the drawing, thick bar portions are based on test results of samples in which soldering was effected in the mode shown in Fig. 4. Namely, in Fig. 4, samples S , S to be jointed were jointed at a soldering surface M. The samples thus soldered were pulled vertically with a tensile strength F to measure the soldering strength. A tension test was conducted ten times or more for each sample, and the results are shown in Fig. 3. The component materials and the soldering material of the present invention were selected by taking into consideration of the results (shown in Figs. 2 to 4) obtained on the basis of the aforementioned tests. In other words, in accordance with the present invention, a shape memory alloy is used for the face-contacting portions such as the sides as well as the rim so that no undue force will be applied to the lens. On the other hand, a β-phase Ti alloy is used for connecting members such as the lug, the joint, and the stud case which require precision machining such as cutting, drilling, and tapping, and a Pd-based soldering material is used for soldering portions. Therefore, it is possible to provide a spectacle frame which is sturdy, fits comfortably with the user's portion to which the spectacle frame is applied, to which no undue force is applied during fitting of the lens, and which has a unique texture.

Claims: A spectacle frame comprising a pair of rims (2) connected by a bridge (5), each rim (2) being provided with a pad arm (4) and being connected to a lug (3) by a brow lug (13), the lug (3) being connected to a side (1) by a joint (12), the pad arms (4), the lug (3), the bridge (5), and the side (1) being formed of shape memory alloy, the respective parts being connected to each other by soldering using a palladium based soldering material, characterized in that the rims (2) are formed of shape memory alloy and in that the joint (12) and the brow lug (13) are made from a β-phase titanium alloy. A spectacle frame according to claim 1, wherein a silver-palladium alloy is used as said palladium-based soldering material.

Inventors: OKAMURA KENJI, OKUDA TOSHIYUKI, SEGOSHI KAZUO, YOSHIDA MIZUO, OKAMURA, KENJI, OKUDA, TOSHIYUKI, SEGOSHI, KAZUO, YOSHIDA, MIZUO
Applicants: SIGMA CO LTD, SIGMA CO. LTD.
Application year: 1989
Main classification: G02C5
IPC codes: G02C1, G02C5