Fixing assemblage for fixing binocular loupes with spectacles

The present invention relates to an assembly of spectacles and binocular loupes attached to the spectacles, the binocular loupes, comprising two loupes, each including at least two lenses of which the ocular lens closer to the eye is smaller than the outer objective lens, whereby the outer surface of a loupe jacket connecting the lenses diverges at a sector angle which expands towards the objective lens, each loupe having a centre axis passing through the centre points of the lenses, the assembly comprising attachment arms of the loupes, the attachment arms including flat crossarms that can be folded at hinge points having hinges made of metal, the loupes being mounted on said flat crossarms.

Such binocular loupes to be attached to spectacles are intended to facilitate precision work, such as the work of a dentist or of a precision mechanician. The drawbacks of prior art binocular loupes include a complicated design and an excessive weight as well as a restricted field of vision caused by the loupes.

US 2,599,716 shows an assembly of spectacles and loupes wherein the distance of the loupes are set by a threaded screw passing through sleeves to which the lens frames of loupes are attached. The loupes are carried by spring legs which are combined with integral cross piece which in turn is connected by means of a pivot hinge to a cross bar having hook members for fitting to a nose bridge of spectacles. The construction is clumsy and urges the loupes too far away from the lenses of spectacles. Therefore, and also because the lenses of loupes have fixed directions with different mutual distances, the construction can not be applied with the binocular loupes. The cross piece and spring legs have their planes of flatness crosswise to the vision direction.

US 1,033,119 shows a binocular loop provided with flexible arms extending in the vision direction outwards from the users face. The distance between the outer ends of these arms is adjustable by moving a rod between the arms. This construction urges binocular loupes too far away from the lenses of spectacles. Therefore the construction is not applicable for binocular loupes having ocular and objective lenses.

US-A-5,381,263 shows a loupes support assembly which provides adjustments of interpupillary distance, convergence angle and view direction of the loupes. The mechanism for changing the mutual distance of the loupes comprises loupe support arms slidably disposed within an assembly housing. An adjustment knob has serrated teeth which engages serrated teeth of each support arm. This kind of mechanism is expensive to manufacture and screens the field of vision because its size is a compromise with durability and ease of handling. Also the weight of the mechanism is a compromise with these factors.

Moreover, e.g. Patent publications US-4,647,165 and US-2,326,787 and US-2,143,431 disclose the placement of various supplemental lenses over a sub-area of the actual lenses by means of mechanical, adjustable arms. These prior art solutions do not afford a sufficient adjustability for the loupes.

The most general drawback in prior art attachment units of loupes based on mechanical attachment arms is the fact that the adjustable attachment assemblies obscure and interfere with the field of vision.

An object of the invention is to provide a fixing assembly for mounting binocular loupes on the user's own spectacles, said assembly being as inconspicuous, easy to use and economically priced as possible. In the attachment of binocular loupes it is important that the fixing assembly and the loupes screen as little as possible of the field of vision, whereby the view can be readily directed past the loupes at the same target that has just been examined and magnified through the loupes.

A particular object of the invention is to provide a fixing assembly for binocular loupes, which is suitable for easy adjustment of the mutual distance of the loupes, which is lightweight, and which is a source of minimal screening of the field of vision caused thereby.

These objects are achieved on the basis of the characterizing features set forth in the annexed claim 1.

Claims 2-3 disclose preferred embodiments of the invention assisting in the individual focusing of loupes for setting the loupes precisely according to the ocular gap of a user.

The invention will now be described in more detail with reference made to the accompanying drawings, in which

fig. 1

is a plan view of a fixing assembly of the invention for attaching loupes to spectacles;

fig. 2

is a frontal view of the binocular loupes shown in fig. 1;

fig. 3

is a side view of the same binocular loupes; and

fig. 4

is a more detailed view of loupe attachment arms with their hinges and adjustment facilities.

The following description deals with the exemplary embodiment shown in figs. 1-4.

Binocular loupes 18 are fastened by means of a bracket 17 to a nose bridge 3 included in spectacles. Each loupe 18 is fitted with at least two lenses of which the ocular lens closer to the eye is smaller than the outer objective lens. As for its outer surface, a loupe jacket 19 connecting the lenses also diverges at a sector angle which is essentially consistent with that drawn from the pupil to the rim of the ocular lens. Thus, restriction of the field of vision caused by the loupes is minimal. The user is able to look through or past the loupes according to his or her choice by just slightly turning the viewing direction and the head.

The loupe jackets 19 may consist of tubes having a thin wall thickness and a conicity which is consistent with said sector angle. The loupe jacket material may be a metal, fiber-reinforced plastics etc. The loupe jacket may have a cross-section which is circular, elliptical or polygonal.

The loupes 18 are mounted on flat crossarms 20 which can be bent at hinge points 21 that are made of a metal and have a shape which changes as a result of bending. The hinge points 21 can be made of a material other than the arms 20, e.g. wire threads embedded in the arm material which is e.g. light metal or fiber-reinforced plastics. The axial directions of hinges 21 are selected so as to control bending of the arms 20 such that, in various positions of the loupes 18, the centre axes thereof cross each other at essentially the same distance from the binocular loupes 18. Thus, the loupes always remain on focus provided that the distance between the loupes is set according to the distance between the eyes.

At the mid-point thereof between the hinges 21, said crossarms 20 are connected to a lengthwise arm 24 whose attachment point is also provided with a hinge 22 made of a resilient metal. The arm element 24 is provided with a lengthwise slot 28 and the arm element 26 with a crosswise slot 27 and, thus, attachment of the arm elements 26 and 24 to each other by means of a screw 25 affords both a lengthwise and crosswise adjustment. The arm element 26 is connected with a hinge 23 to a yoke-like clip 6a which is mountable from above (or from below) on a metal attachment body 6b, having its sides provided with grooves 6c and the inner surfaces of the yoke 6a being shaped accordingly. In this case, the members 6a and 6b together provide an attachment clip, generally designated by reference numeral 6. With this snap-fit coupling, the binocular loupes are readily removable and replaceable. The small-sized and inconspicuous attachment body 6b can be permanently fixed to the nose bridge 3 of spectacles. The attachment body 6b can be fixed to nearly all types of spectacles by using a clamping hook 10, made of a soft metal and constituting a loop which grips around the nose bridge 3 and whose ends are received in a hole extending through the attachment body 6b and dimensioned identically to the hole in the member 8 in fig. 6, i.e. in such a manner that the threads of a screw 7 engage with those of the clamping hook 10. Such a clip is small, inconspicuous and firm and adaptable to nearly all types of spectacles.

What is essential about the invention is that the fixing assembly and the loupes are lightweight and only obscure a small section of the field of vision. This objective can be favouved even further by designing a thin-walled loupe jacket so as to comply with the sector angle of a field of vision covered by a small-sized ocular lens. In addition, the flat shape and positioning of attachment arms are selected so as to interfere minimally with the field of vision. At the same time, however, the attachment arms, with the aid of their hinge points, enable an individual alignment and setting of the distance between the eyes, such that the loupes have a focus always fixed in position. The loupes may have a length of e.g. 20 - 30 mm. The ocular lens may have a diameter of e.g. about 10 mm. The ocular lens' distance from the eye is in the order of 20 mm when the lens is positioned very close to the lens of spectacles. The objective has a diameter which is determined by the sector angle and the length of the loupes.