GB2266783A

GB2266783A - Hinge mechanism for spectacles

Info

Publication number: GB2266783A
Application number: GB9209684A
Authority: GB
Inventors: Yuet Charn Leung
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-05-01
Filing date: 1992-05-01
Publication date: 1993-11-10
Anticipated expiration: 2012-05-01
Also published as: GB2266783B; GB9209684D0

Abstract

A hinge mechanism, especially for a pair of spectacles, comprises a housing 1 with an elongate recess therein, and a core assembly 3 within the recess and incorporating at least part of a pivot link 19, 20, 23. The core assembly comprises a core member 5 displaceable within the recess in response to pivoting movement of the pivot link, and a bush 7 within which the core member 5 is slidable and which is retained in fixed position within the recess by being screwed to an internal thread 21 in the recess. The screw thread fastening replaces a conventional fixing pin. <IMAGE>

Description

HINGE MECHANISM AND METHOD OF CONSTRUCTING THE SAME The invention relates to a hinge mechanism, in particular for use in spectacle frames, and a method of making such a mechanism.

Hinges are used to connect the lens frames with the side pieces of spectacles. It is common for these hinges to be of the double-action type i.e.

pivotable through 1800. Hinges of this type are often spring-loaded to ensure that the spectacle frame is rigid when the side pieces are perpendicular to the lens frame.

Hinges as described above have been constructed from a hollow casing which is fixed into the frame side piece. The casing has an asymmetrical bore into which is located a core piece. The core piece is held in the casing by a locating pin which during manufacture of the hinge is fixed through the casing and is seated in a recess in the core piece.

The core piece is shaped to fit within the casing and cooperates with a spring mounted concentrically on a rod, the spring abutting a stop plate at one end of the rod. At the other end of the rod a portion of the rod of enlarged dimensions is provided with an eye in which the pivot pin of the hinge can be received to pivotably attach a member which is fixed to the lens frame.

Between the enlarged portion of the rod which has the eye and the spring is a bush which contains a recess in which the locating pin fits. Spring action is achieved when the eye/pivot is urged forward against the spring due to rotation of the side piece about the lens frame, because the bush is fixed by the pin to the casing and the rod slides within the bush.

As can be appreciated; this construction of hinge has disadvantages. The"$ocating.pin is very small and it is difficult to locate the pin inside both the hole in the casing and the recess in the bush. The bush must be aligned correctly with the hole, which can be difficult to achieve. To overcome this problem the core piece is shaped to fit within a slot in the casing but this requires the core piece to be inserted in the correct orientation relative to the casing, which makes construction of the hinge a delicate and complicated operation. The use of a single pin to hold the bush in place is undesirable as it is subject to the force of the spring and could shear under repeated use. The hinge cannot be adjusted or disassembled once made.

It is an object of the present invention to overcome all or some of these disadvantages.

In accordance with the invention there is provided a hinge mechanism for pivotably connecting a first member to a second member through a pivot link, comprising a housing connectable to the first member and having an elongate recess therein with an internal screw-threaded zone; a core assembly receivable within the recess and incorporating at least part of the pivot link for connection to the second member; wherein the core assembly comprises a core member longitudinally slidingly displaceable within the recess in response to pivoting movement of the pivot link, and a bush which limits displacement of the core member and within which the core member is slidable and which is retained in fixed position within the recess by being screwed to the internal thread of the recess.

Preferably, the core member carries a stop member at its end remote from the pivot link, and spring means act between the stop member and the bush to generate a biassing force against which the core member is displaced outwardly of the housing.

Preferably, the bush has an externally screw threaded annular portion for engagement with the housing and a pair of diametrically opposed legs extending longitudinally from the annular portion and defining guide surfaces for a portion of the core member.

Also in accordance with the invention there is provided a method of assembling such a hinge mechanism which comprises the steps of assembling the core assembly and thereafter inserting the core assembly into the housing including screwing the bush into position to retain the core assembly in the housing.

Preferably the recess in the housing is substantially cylindrical. Advantageously the longitudinal axis of the recess is inclined with respect to the longitudinal axis of the housing. This has the further advantage that the movement of the pivot link parallel to the housing. axis does not directly pull on the core member; only a component of the pulling force is applied in the direction of the longitudinal axis of the housing. The spring means may be a helical compression spring encircling the core member.

A specific embodiment of the invention will now be described by way of example and with reference to the following drawings, in which: Figure 1 is a sectional view of one embodiment of a hinge according to the present invention, Figure 2 is a sectional plan view of the hinge shown in Figure 1, Figure 3 is the same view of the hinge as shown in Figure 2, after part of the hinge has been rotated through 900 in the direction of the arrow shown in Figure 2.

Figure 4 is a sectional plan view of a pair of spectacles incorporating hinges as shown in Figures 1 to 3, Figure 5 is a sectional plan view of a prior art hinge, and Figure 6 is a plan view of the housing of a prior art hinge.

Referring first to Figures 1 and 2, a hinge according to the invention comprises an elongate generally cylindrical housing 1 closed at one end.

Inside the housing is located a core assembly shown generally by the arrow 3.

The core assembly comprises a rod 5 which has an eye at one end, a block portion 6a adjacent to the eye and a cylindrical portion 6b which is externally screw-threaded at its end. The rod 5 is slidable within a bush 7. The bush 7 has an annular externally screw-threaded portion and a pair of diametrically opposed legs one on each side of the block portion 6a of the rod. The external screw thread is indicated at 9. A helical compression spring 11 is concentrically mounted on the cylindrical portion 6b of the rod 5 and acts between one end of bush 7 and an enlarged diameter stop 13 screwed to the end of the rod 5. The internal shape of the bush 7 defines an abutment surface or shoulder 14 against which the block portion 6a of the rod normally rests.

The core assembly 3 is substantially cylindrical with a diameter which will fit into a bore in the housing 1. When assembled, the external screw thread 9 engages with an internal screw thread 21 on the inside of the bore of the housing 1. Thus, the rod 5 is then movable back and forth to a limited extent in the manner of a plunger, as shown in Figure 3.

After the core assembly has been screwed into the housing, a frame link 19 is pivotably attached by a pivot screw 20 to the free end of the core assembly that protrudes from the housing 1. The pivot screw 20 is fitted through the eye of the rod end.

The frame link comprises a pair of legs 23 positioned one on each side of the protruding end of the rod 5 and thus retained by the pivot screw 20 and a hook end 25 which can engage with the plastic moulded lens frames of a pair of spectacles. The frame link 19 is short and stubby to fit within the narrow lens frame and can be attached to this frame by screws or by injection moulding of the plastic around the frame'link 19. The core assembly 3 is attached to the side piece of a spectacle frame by a similar suitable method.

When the frame link is rotated from the position shown in Figure 2 in the direction of arrow A, the rod 5 slides against the bias of the spring 11 within the bush 7 (which is screwed to the tubular housing 1) and the frame link adopts the position shown in Figure 3. Of course the frame link could also be rotated through 900 in the opposite direction to arrow A.

The ease of disassembly of the core assembly from the housing is considered an advantage of this hinge. However it may not be desirable that, once assembled, the core assembly of the spectacle hinge can be unscrewed from the housing. Therefore a further embodiment of the invention can include any suitable means permanently to fix the core assembly within the housing (for example adhesive or a pin similar to the prior art). If a pin is used to fix the core, unlike the prior art, the screw-threaded core of the present invention will precisely locate the bush opposite a hole for insertion of the pin. The bush can be grooved like the prior art or can have a single hole through which the pin is located. Such a pin acting to fix the screw thread within the core is not used as the sole means which holds the core within the casing.

Therefore the pin is unlikely to shear as it is subject to less force.

Figure 5 shows a typical prior art hinge mechanism where a small pin 26 is used as the sole means to retain the bush 7 within the housing 1. The pin 26 has to be aligned with a hole in the bush.

The hinge of the invention has the advantage that it is more robust and that, in at least one embodiment, can be easily disassembled for repair or replacement of component parts. The method of assembly is quicker and cheaper than prior art methods as the core assembly does not have to be in a precise orientation relative to the housing before insertion in the housing.

Claims

CLAIMS:

1. A hinge mechanism for pivotably connecting a first member to a second member through a pivot link, comprising a housing connectable to the first member and having an elongate recess therein with an internal screw-threaded zone; a core assembly receivable within the recess and incorporating at least part of the pivot link for connection to the second member; wherein the core assembly comprises a core member longitudinally slidingly displaceable within the recess in response to pivoting movement of the pivot link, and a bush which limits displacement of the core member and within which the core member is slidable and which is retained in fixed position within the recess by being screwed to the internal thread of the recess.

2. A hinge mechanism as claimed in claim 1, in which the core member carries a stop member at its end remote from the pivot link, and spring means set between the stop member and the bush to generate a biassing force against which the core member is displaced outwardly of the housing.

3. A hinge mechanism as claimed in claim 1 or 2, in which the bush has an externally screw-threaded annular portion for engagement with the housing and a pair of diametrically opposed legs extending longitudinally from the annular portion and defining guide surfaces for a portion of the core member.

4. A hinge mechanism as claimed in any preceding claim, in which the bush defines a stop limiting displacement movement of the core member into the housing.

5. A hinge mechanism as claimed in any preceding claim, in which the longitudinal axis of the recess is inclined with respect to the longitudinal axis of the housing.

6. A hinge mechanism as claimed in any preceding claim, in which the pivot link is pivotable through 1800.

7. A hinge mechanism substantially as hereinbefore described with reference to Figs. 1 to 3 of the accompanying drawings.

8. A method of assembling a hinge mechanism as claimed in any preceding claim, which comprises the steps of assembling the core assembly and thereafter inserting the core assembly into the housing including screwing the bush into position to retain the core assembly in the housing.

9. A method as claimed in claim 7, which includes permanently securing the core assembly within the housing after threaded engagement of the core assembly and housing.

10. A pair of spectacles incorporating a hinge mechanism as claimed in any of claims 1 to 7.