GB2268282A

GB2268282A - Elastic hinge for spectacles

Info

Publication number: GB2268282A
Application number: GB9213258A
Authority: GB
Inventors: Wai Chung Kenneth Ng
Original assignee: OTTICA FAR EAST Ltd
Current assignee: OTTICA FAR EAST Ltd
Priority date: 1992-06-23
Filing date: 1992-06-23
Publication date: 1994-01-05
Also published as: GB9213258D0

Abstract

The hinge device comprises a first hinge element 24 connectable to the end of a temple 10 which is rotatable more than 90 DEG with respect to a front portion of a pair of spectacles, and a second hinge element (27, Fig. 2) connectable to the front of a pair of spectacles and being pivotally connected to the first hinge element The first hinge element 24 has a hollow body 11 having formed therein a blind hole 13 which accommodates a screw 16 having a head 17. A spring 14 is located between the head 17 of the screw and a sleeve-like abutment element 18 inserted into the blind hole 13. The abutment element 18 has an edge 20a which engages an annular undercut seat 40 defined by a frustum-shaped bore 21 formed in the internal wall of the blind hole 13, whereby the screw 16, the spring 14 and the abutment element 18 are retained in the blind hole 13. <IMAGE>

Description

IMPROVED ELASTIC HINGE FOR SPECTACLES The present invention relates to an improved elastic hinge for spectacles.

Elastic spectacle hinges are already known which permit the temples of the spectacles to be opened beyond 90" with.

respect to the front part of the spectacles, with elastic return to the usual 90 position. One type of known elastic hinge is constituted by an elongated hollow body provided at the end of a stem or temple of the spectacles. The body contains a cylindrical helical spring located between the head of a pin, which passes axially through the spring, and an abutment element. The abutment element is locked in the hollow body by means of a seeger ring or snap ring, which is accommodated in an annular seat of the elongated hollow body and also enters a bore formed in the abutment element.

The pin passes through the abutment element and engages a first hinge element having pivotally connected thereto a second hinge element, which is fixed to the front of the spectacles. The second hinge element has a polygonal profile; one of its sides rests on a flat end of the hollow body.

This known type of hinge is appreciated for its simple manufacture and easy assembly, since its elements are in fact first pre-assembled externally and then inserted into the hollow body and locked therein by means of the snap ring. However, the above described hinge is not free from drawbacks, the most important of which resides in the fact that in order to insert the pre-assembled elements into the hollow body, it is necessary to use a tool to compress the snap ring until it can be inserted in the hollow body.

This entails difficulties during assembly and causes an increase in the assembly cycle time.

Accordingly, the aim of the present invention is to provide an improved elastic hinge for spectacles which eliminates the problems encountered in the known elastic hinges.

A consequent primary object is to provide an improved elastic hinge for spectacles which is composed of an even smaller number of elements.

Another object is to provide an elastic hinge whose structure is even simpler than the-one described above.

Not least object is to provide a hinge which can be manufactured at low cost with conventional facilities and equipment.

This aim, these objects and others which will become apparent hereinafter are achieved by an improved elastic hinge for spectacles, of the type which comprises an elongated hollow body connectable to the end of a temple and containing elastic means arranged between the head of a screw and an abutment element locked in said hollow body, said pin passing axially through said elastic means and through said abutment element and engaging a first hinge element to which a second hinge element is pivoted, said second hinge element being fixable to the front of a pair of spectacles, one side of said second hinge element resting on a flat end of said hollow body, said hinge being characterized in that said hollow body has a frustum-shaped bore formed therein, and in that said abutment element comprises a tubular element inserted into and engaging said frustum-shaped bore, said tubular element having flat faces arranged oblique with respect to the longitudinal axis of said hollow body and parallel to each other.

Further characteristics and advantages of the invention will become apparent from the detailed description of an embodiment thereof, illustrated only by way of nonlimitative example in the accompanying drawings, wherein: figure 1 is a perspective view of the part of elastic hinge which is fixed to the temple of a spectacle frame; figure 2 is an exploded perspective view of the entire hinge; figure 3 is a cross-sectional view of the hinge part of figure 1; figure 4 is a cross-sectional view of the abutment element of the hinge of figures 1-3.

With reference to the above figures, the improved elastic hinge for spectacles according to the invention comprises an elongated hollow body 11 which is fixable to the end of a temple 10 and has a flat end face 12 provided with a cylindrical blind hole 13, which extends longitudinally within the body 11.

A cylindrical helical spring 14 is accommodated in said cylindrical hole 13 and surrounds the stem 15 of a screw 16.

The screw 16 has a head 17 which abuts an end of the helical spring 14.

The end of the screw 16 opposite to the head 17 rests on an abutment element 18 which is locked in place within the hollow body 11 in a manner which will be described hereinafter.

According to the invention, the abutment element 18 comprises a sleeve-like tubular element defining substantially flat faces 19 and 20 which are arranged obliquely with respect to the longitudinal axis of the tubular element 18 and the hollow body 11, and are substantially parallel to each other.

The abutment element 18 advantageously has a cylindrical configuration and an external diameter which is less than the diameter of the hole 13 such that it can be inserted with a slight play into the hole 13.

The hinge device also has means for locking the abutment element 18 in the hole 13. The means for locking comprise a frustum-shaped bore 21 which is defined in the hole 13 having a tapered lateral wall which converges inwardly in a direction extending from the open end of the hole 13 towards the blind end 13.

The narrowest end of the frustum-shaped bore 21 has a diameter substantially corresponding to the diameter of the blind hole 13, while the widest end of the frustum-shaped bore 21 defines an annular undercut seat 40 in the internal wall of the hole 13. When the abutment element is arranged within the frustum-shaped bore 21 in the hole 13, the flat faces 19,20 of the abutment element 18 are forced, by interaction with the spring 14, into a position which is perpendicular with respect to the longitudinal axis of the hole 13. Thus, the outer annular wall of the abutment element 18 is inclined with respect to the axis of the hole 13, so that the axial extension of the element 18 is substantially equal to the shortest distance between the flat faces 19 and 20 of the element 18, i.e., as defined by a line extending perpendicularly from the face 19 to the face 20.

During assembly of the hinge, the abutment element 18 surrounds a portion of the stem 15 of the screw 16, is inserted into the hole 13 and is guided axially thereby.

When the abutment element 18 arrives at the frustumshaped bore 21, the space available to the abutment element 18 increases and one of the flat faces 19 abuts the spring 14. The pressure of the spring 14 elastically forces the flat face 19 to become arranged at right angles to the axis of the hole 13, and a corner 20a defined by the abutment element 18, at the face 20 thereof, engages in the annular undercut seat 40 defined by the frustum-shaped bore 21.

The abutment element 18 is thereby locked inside the hollow body 11.

The stem 15 of the screw 16 thus passes through the abutment element 18, and its threaded end engages a complementarily threaded hole of a wing 23 which extends from a first hinge element 24.

The first hinge element 24, which advantageously has a polygonal cross-section, is inserted between the walls of a recess 25 provided at the end of the hole 13 in the hollow body 11.

Said first hinge element 24 protrudes from the body 11 and has a hole 26 for pivoting to a second hinge element 27 which is substantially fork-shaped and has holes 28 for the pivoting of a screw pivot 29.

The second hinge element 27 is fixed to the front 30 of a pair of spectacles.

The outer profile of the fork of said second hinge element 27 is rectangular and comprises three sides, one of which rests on the end face 12 of the hollow body 11.

The three sides define three positions of stable equilibrium for the rotation of the temple 10, which occurs with the compression of the spring 14 due to the traction applied by the first hinge element 24 and thus by the screw 16.

From what has been described above, it is thus evident that the abutment element 18 is fixed to the hollow body 11 directly, without the aid of any elastic element.

The elements of the hinge, i.e., the screw 16, the spring 14 and the abutment element 18, are first preassembled externally and are then inserted into the blind hole 13 formed in the hollow body 11 with a simple insertion action, without thereby requiring the aid of any tool.

It is sufficient to insert the abutment element 18 in an axial arrangement into the hole 13.

The screw 29-is then inserted into the holes 26 and 28 for interconnecting the body 11, connected to a temple 10, to the second hinge element 27 connected to the front piece 30 of the spectacles. When the temple 10 is angularly positioned at over 90C from the front 30, the end 50 of the temple 10 abuts a corner 51 of the front 30 and the first hinge element 24 is slightly withdrawn from the blind hole 13 against the elastic biasing of the spring 14. Upon releasing the temple 10, the spring 14 causes the first hinge element 24 to retract to its normal location with respect to the blind hole 13, the end 50 of the temple 10 contemporaneously pivots on the corner 51 of the front 30, and the temple 10 automatically returns to a position whereat it is located at approximately 90' with respect to said front 30.

The hinge device according to the invention entails a smaller number of hinge parts, greater simplicity in manufacture and shorter assembly times.

In practice it has thus been observed that the intended aim and objects of the present invention have been achieved.

The materials employed, so long as they are compatible with the contingent use, as well as the dimensions, may be any according to the requirements.

Claims

1. Improved elastic hinge for spectacles comprising an elongated hollow body connectable to the end of a temple and containing an elastic means arranged between the head of a screw and an abutment element locked in said hollow body, said screw passing axially through said elastic means and said abutment element and engaging a first hinge element to which a second hinge element is pivoted, said second hinge element being fixable to the front of a pair of spectacles, one side of said second hinge element resting on a flat end of said hollow body, said hinge being characterized in that said hollow body has a frustum-shaped bore formed therein, and in that said abutment element comprises a tubular element inserted into and engaging said frustum-shaped bore, said tubular element having flat faces arranged oblique with respect to the longitudinal axis of said hollow body and parallel to each other.

2. Hinge according to claim 1, characterized in that said frustum-shaped bore tapers toward the bottom of a blind hole formed in said hollow body, said screw, said elastic means and said abutment element being inserted in said blind hole.

3. Hinge according to claims 1 and 2, characterized in that the axial dimension of said bore is at least equal to the distance between said flat faces of said tubular element which constitutes said abutment element.

4. Hinge according to claim 1, characterized in that said first hinge element has a polygonal cross-section and is guided between the walls of a recess provided in said hollow body at the end of said blind hole for the insertion of said elements.

5. Improved elastic hinge for spectacles, according to one or more of the preceding claims, characterized by what is described and illustrated in the accompanying drawings.