GB2149530A

GB2149530A - A fastener lug for metal opthalmic mountings

Info

Publication number: GB2149530A
Application number: GB08424299A
Authority: GB
Inventors: Kurt Schonhut
Original assignee: Ferdinand Menrad GmbH and Co KG
Current assignee: Ferdinand Menrad GmbH and Co KG
Priority date: 1983-09-26
Filing date: 1984-09-26
Publication date: 1985-06-12
Also published as: FR2552561A1; IT8404867A1; DE3334808A1; DE3334808C2; IT1180291B; FR2552561B3; GB2149530B; IT8404867A0; JPS60156036A; GB8424299D0

Abstract

A two-part fastener lug (16) for the rim (12) of a spectacle frame is made up of a screw bearing jaw (16) and of a jaw (20) driven by a screw (22) fitting in a threaded hole in the screw bearing jaw so that the two jaws may be tightened up and the lug closed. The driven jaw is in the form of a narrow solid plate that may be fitted into a chamber in the screw bearing jaw to the side of the screw, which has a shoulder (36) positively driving the driven jaw towards the screw bearing jaw. The arrangement is particularly suited to the use of titanium mountings. <IMAGE>

Description

SPECIFICATION A fastener lug for metal ophthalmic mountings The present invention relates to a fastener lug for screwing up split metal ophthalmic mountings, and more specially although not exclusively to a lug for tightening up mountings made of titanium onto the lenses therein comprising a screw bearing jaw with a screw threaded hole running generally in the direction of the edge of the lens, a screw in the hole and a screw driven jaw adapted to be positively engaged by a shoulder on the screw, the screw bearing and screw driven jaws being fixed on two ends of a split rim forming part of the mounting.

The rim of such ophthalmic mountings is split to enable it to be opened out somewhat to put in a lens, after which the rim is closed and tightened using the screw of the lug. To keep the weight of the spectacles as low as possible and furthermore to adapt the mounting to different fashions, the rim will very frequently have a very small cross section. The screw bearing jaw with the screw thread and the screw driven jaw to be tightened against it are welded or or brazed to the rim. In designs so far produced the tightening screw runs through a hole in the screw driven jaw. It is very hard to produce a connection between the delicate, sleeve-like screw driven jaw and the rim.

Such difficulties are prone to be particularly accentuated in the case of titanium mountings. Producing a connection between titanium and spelter is an exacting operation, and for welding a high electrode pressure is needed which would be likely to crush the delicate sleeve member.

For this reason one object of the invention is to so design a lug of the sort named so thaat although the mounting at the lug is delicate, manufacture is simplified and for this reason more economic.

A further object is to produce such a fastener lug that is well suited for use on titanium mountings.

In order to effect these and further objects, the present invention consists in a fastener lug for screwing up a split metal ophthalmic mounting onto a lens therein, comprising a screw bearing jaw with a screw threaded hole running generally in the direction of the edge of the lens, a screw in the hole and a screw driven jaw adapted to be lockingly engaged by a shoulder on the screw, the screw bearing and screw driven jaws being fixed on two ends of a split rim forming part of the mounting, the screw driven jaw being made of solid material and, when the rim is in the tightened up condition, fitting generally in the direction of the rim into a chamber in the screw bearing jaw and being kept in place by the shoulder on the screw into the screw bearing jaw.

Because the screw driven jaw is solid, it is able to stand up to a high welding electrode pressure without any special steps having to be taken (in an attempt) to keep a jaw in the form of a sleeve from being flattened by the electrode pressure. In the invention the screw driven jaw may be made in the form of a narrow, flat plate.

In keeping with a useful development of the invention, the screw bearing jaw has a groove therein into which the rim fits, the groove having a portion remote from the screw driven jaw corresponding to the cross section of the rim where the rim and the screw bearing jaw are joined together, and a further portion adjacent to the screw driven jaw widened out in the form of the chamber to take up the screw driven jaw.

A more specially useful effect may be produced in this respect, if the end of the rim, which is fixed to the screw bearing jaw, projects for roughly the same distance into the portion of the chamber as the distance by which the screw driven jaw projects past the end of the rim joined thereto in the length direction thereof.

In keeping with another convenient and beneficial development of the invention, the chamber part of the groove is limited by a shoulder next to the portion adapted for fixing to the rim, the threaded hole (that has the tightening screw therein) opening through the shoulder.

Preferably, the screw driven jaw is in the form of a flat plate, whose breadth is roughly equal to the breadth of the rim as measured in a direction normal to the plane of the lenses.

A more detailed account of the invention will now be given on the basis of a working example to be seen in the figures.

Figure 1 is a view from the front of one half of a metal ophthalmic mounting or spectacle frame.

Figure 2 is a view of the lens securing lug in the undone or opened position of the rim looking in the direction of arrow II in Figure 1 and on a larger scale.

Figure 3 is a section taken on the line Ill-Ill of Figure 2.

Figure 4 is a section on the same lines as Figure 3, but with the rim in the fastened or secured condition.

Figure 1 shows the one half of a metal ophthalmic mounting 10 for the right eye, the rim 12 for securing the lens in position being joined on the one side with a bridge 14 and on the other side with a two-piece securing lug 16, which is furthermore fitted with a hinge for one of the temples.

At the securing lug 16, the rim 12 is split and the two ends of the rim 12 are each fitted with one jaw of the lug 16, such jaws being the screw bearing jaw 18 and the screw driven jaw 20. The joint between the jaws and the rim may be more specially a welded one. The two parts of the lug, viz. the screw bearing or screw threaded jaw 18 and the screw driven jaw 20, are secured together by a lug screw 22. After undoing the lug screw 22, the rim 12 may be opened out to put the lens in place or to take it out.

On its side nearest the rim 12 the screw bearing jaw 19 joined to the top end of the rim 12 has a groove 24 matching the cross section of the rim 12, the groove 24 running right the way from the top to the bottom of the side face 26 and the lower part of the groove being so deep that the side edges 26 and 27 and the edge portion 30, defining the floor of the groove, generally delimit a chamber 32, which is U-like in plan. Not only the rim 12 but furthermore the screw driven jaw 20 and the shank 34 of the securing screw 22 may fit into the chamber 32, which at its top is limited by a shoulder 36 reducing the cross section of the top part of the groove 24 to the cross section of the rim 12 so that a top wall 38 of the screw bearing jaw 18 is produced.There is a threaded hole 40 running through this wall 38 of the jaw 19 in a direction parallel to the groove 24 and so roughly parallel to the rim 12. The lens securing screw 22 is fitted in the hole 40.

The top end of the rim 12 is embedded in the top shallow portion 42 of the groove 24 and is fixed securely here to the screw bearing jaw 18, the rim projecting somewhat past the shoulder 36 into the wider part (forming the chamber 32) of the groove so that it partly covers over the chamber.

Preferably by welding, the lower end of the rim 12 is joined to the outer face of the screw driven jaw 20, which as seen looking in a direction parallel to the plane of the lens, has a breadth generally equal to the breadth of the rim 12 and so of the groove 24 as well. The screw driven jaw projects generally the same distance past the end of the rim as the other end of the rim 12 projects past the shoulder 36 into the chamber 32. Measured in the length of the screw driven jaw 20 is generally the same as the length of the chamber 32.The screw driven jaw 20 is made of a narrow piece of strip so that it has the form of a rectangular block and has two planar end faces 44 and 46, of which one faces the shoulder 36 and the other is in generally the same plane as the chamber 48, remote from the wall 38, of the screw bearing jaw 18, when the end face 44 is resting on the shoulder 36 so that there is a common support face 46 and 48 for the head 50 of the lens securing screw 22, when the screw driven jaw 20 has been moved into the screw bearing jaw 18 so far that the end face 44 runs against the shoulder 36 or the two ends of the rim 12 are abutting in the secured position of the rim 12. The top or inner face of the screw head 50 next to the screw shank 34 forms a shoulder 52 which firmly secures the two parts 18 and 20 of the lug after tightening the securing screw 22.

The structure described makes it relatively simple for a reliable connection to be produced between the lug 16 and the rim even if the materials are not readily connected, as for example in the case of titanium, because as a solid part the screw driven jaw is no trouble to weld since it withstands the heavy pressure then needed. The relatively simple form of the parts and the simple way in which they may be assembled furthermore lowers costs.

Claims

1. A fastener lug for screwing up a split metal ophthalmic mounting onto a lens therein, comprising a screw bearing jaw with a screw threaded hole running generally in the direction of the edge of the lens, a screw in the hole and a screw driven jaw adapted to be lockingly engaged by a shoulder on the screw, the screw bearing and screw driven jaws being fixed on two ends of a split rim forming part of the mounting, the screw driven jaw being made of solid material and, when the rim is in the tightened up condition, fitting generally in the direction of the rim into a chamber in the screw bearing jaw and being kept in place by the shoulder on the screw screwed into the screw bearing jaw.

2. A fastener lug as claimed in claim 1 wherein said screw bearing jaw has a groove therein into which the rim fits, said groove having a portion remote from the screw driven jaw corresponding to the cross section of the rim where the rim and the screw bearing jaw are joined together, and a further portion adjacent to the screw driven jaw widened out in the form of the chamber to take up the screw driven jaw.

3. A fastener lug as claimed in claim 2 wherein the one end of the rim fixed to the screw bearing jaw projects into the chamber by about the same distance as the screw driven jaw projects past the end of the rim joined to it, in the length direction of the rim.

4. A fastener lug as claimed in claim 2 or claim 3 wherein the said chamber of the groove is delimited by a shoulder next to part of the groove adapted for joining to the rim, the threaded hole for the screw opening through this shoulder.

5. A fastener lug as claimed in any one of the claims hereinbefore wherein said screw driven jaw is in the form of a flat plate with a breadth roughly equal to the breadth of the rim as measured normal to the plane of the lens.

6. A fastener lug as claimed in any one of the claims hereinbefore wherein the screw bearing jaw and the screw driven jaw are welded to the rim.

7. In combination, a titanium ophthalmic mounting and a fastener lug as claimed in claim 1.

8. A fastener lug substantially as described hereinbefore with reference to and as illustrated in the accompanying drawings.