HINGE

Abstract: The hinge comprises first and second components (l0,l2) for attachment to respective structural members. A substantially cylindrical surface (26) on the second component (l2) snap-fits into a part-­ cylindrical bearing surface (20) on the first component (l0). The components (l0,l2) have interengaging formations which act to resist closing over a predetermined arc; in the embodiment shown one set of interengaging formations comprises blades (28) sliding in slots (22), and another set comprises protrusions (32,34).

Description: This invention relates to hinges. The invention is particularly but not exclusively concerned with hinges for use in applications such as the lid of a chest-type freezer. In such applications it is desired to provide a hinge which will allow the lid to be lifted to an open position and will retain the lid in that position until it is positively closed by the user. It is also desirable that the user may open the lid to any selected angle within a range of opening angles. These objects have conventionally been met by the use of a metal hinge comprising two body components, a hinge pin, and a counterpoise torsion spring. Such an arrangement is expensive and complex to assemble. Hinges are known which do not use counterpoise springs. One such hinge which is described in EP-A-013388 is formed from a first component having a concave surface for receiving in a snap-fit arrangement, a generally cylindrical surface. The diameters of the concave and convex surfaces are approximately equal so that the components are a tight fit and can thereby be held relative to each other by friction. The frictional retaining force produced is, however, limited and could not for example withstand the weight of a partially open chest freezer lid. Furthermore the hinge does not provide a variable retaining force. In US Patent No 4,506,408 corresponding to the preamble of claim 1 the components are held at selected positions with respect to one another by means of the intermeshing of a series of corresponding ribs and grooves provided on the inner surface of one component and the adjacent outer surface of the second component. To allow the components to rotate relative to one another, the ribs and/or the protrusions separating the grooves are resilient. This hinge, however, does not provide a variable retaining force. Accordingly the present invention provides a hinge as defined in claim 1 and preferred embodiments as defined in the dependent claims appearing hereinafter. Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a perspective view of a body component; Figure 2 is a perspective view of a lid component; Figure 3 is a side view illustrating the assembly of the hinge; Figure 4 is a side view of the hinge in the closed position; Figure 5 is a side view of the hinge in a partially open position; Figure 6 is a side view of the hinge in a fully open position; and Figure 7 is a perspective view showing part of a hinge arrangement in accordance with another embodiment. Referring to Figures 1 and 2, the hinge comprises a body component l0 which is integrally moulded from polypropylene and a lid component 12 which is integrally moulded from ABS. Each of the components 10 and 12 is provided with a plate-like portion 14 having holes 16 for fastening means, such as self-tapping screws. The body component 10 has an end portion 18 of generally part-cylindrical form whose interior is moulded to provide a number of ribs having inside faces 20 providing a part-cylindrical bearing surface and defining four circumferential grooves 22. The lid component 12 has an end portion 24 comprising a solid cylindrical part 26 from which extend four blades 28. Turning to Figure 3, the hinge can be assembled by orienting the parts 10 and 12 as shown and forcing them together. Since the bearing surface 20 extends over more than 180° the cylindrical part 26 becomes trapped therein as shown in Figure 4. This arrangement makes the hinge particularly suited to automatic assembly methods. In this assembled condition, the blades 28 are positioned within the grooves 22 to provide mutual engagement as discussed in more detail below. The lid component 12 has a transverse wall portion 30 which includes a protrusion 32. The outer surface of the body component end portion 18 is of part-cylindrical shape but is provided with a convex protrusion 34. The protrusions 32 and 34 are positioned and dimensioned such that they engage with each other over an opening arc from the 40° position shown in Figure 5 to a 60° position to retain the lid open. Preferably the blades 28 and grooves 22 are also arranged to provide engagement over an opening arc between 40° and 90°. This angle of engagement may be provided by suitable shaping of the thickness of the blades 28 and/or the grooves 22, or by the provision of protrusions on one or other of these at appropriate angular spacings. The engagement between the protrusions 32 and 34, and that between the blades 28 and grooves 22, is partly of a frictional nature since the relevant surfaces are in rubbing contact. Additionally, however, the parts are so dimensioned that the interengagement causes elastic deformation; this produces a high degree of force akin to a spring force opposing closing movement, eg closing movement of a lid under gravity. The hinge of this embodiment therefore rotates freely from the closed position to the 40° position. Between 40° and 60° (where the closing effect of the weight of the lid is greatest) a relatively high frictional resistance is provided by the protrusions 32 and 34 acting as a primary friction pad plus the blades and grooves 28, 20 acting as a secondary friction pad, and between 60° and 90° a relatively lower degree of friction is provided by the secondary friction pad only. Fig 7 illustrates a modified embodiment in which two lid components 12′, each substantially similar to the lid components 12 of the first embodiment are formed integrally as part of a moulding 36. The moulding 36 has a plane outer surface 38 and an internal flange 40 which can be received within a box-like lid such that the moulding 36 forms an end cap for the lid. This moulding 36 can be used with the body components 10 of Figs 1-6.

Claims: A hinge comprising a first component (10) and a second component (12), each having a first portion (14) for attachment to a respective structure; the first component (10) having a second portion (18) shaped to provide a surface (20) of generally part-cylindrical form extending over an arc greater than 180°; the second component (12) having a second portion (24) presenting a convex generally cylindrical surface (26) of a diameter matching that of said part-cylindrical surface of the first component (10); said second portion (18) of the first component (10) being arranged to receive said second portion (24) of the second component (12) in a snap-fit manner with surfaces in engagement; said components (10,12) further including formations (28 32;22,34) which interengage over a predetermined part of the opening arc of the hinge to maintain the first and second components within said predetermined part of the opening arc; characterised in that said formations (28,32;22,34) interengage in such a manner as to produce elastic deformation thereby providing a frictional force tending to maintain said first and second components in any selected position relative to one another; and in that said interengaging formations (28,32;22,34) comprise first formations (32,34) which interengage only over a first arc, and second formations (22,28) which interengage over said first arc and additionally over a second arc, wherein said first formations (34) comprise a convex protrusion (34) formed upon a part-cylindrical outer surface of said second portion (18) of the first component (10) and a protrusion (32) formed on said second component (12), and wherein said part-cylindrical surface (20) of said second portion (18) of said first component (10) is a concave bearing surface and has disposed thereon one of said second formations (22). The hinge of claim 1 wherein said second formations comprise at least one blade (28) extending radially from said convex surface (26) of said second component (12), and at least one groove (22) formed in said concave, bearing surface of said first component in which said blade engages over said first and second arcs. The hinge of claims 1 or 2 wherein the first formations are positioned and dimensioned such that they engage with each other over the first arc from 40° to 60°. The hinge of claim 3 wherein the first formations act as a primary frictional force between 40° to 60° to maintain the first and second components in any selective position relative to one another and the second formations engage with one another between 40° and 90° to provide a secondary frictional force. The hinge of any one of the preceding claims wherein each component (10,12) is a one-piece plastics moulding. A double hinged assembly comprising first and second hinges spaced along an elongate structural member (38), each of said hinges comprising first and second first portions (14) and first and second second portions (18,24) all as defined in any one of the preceding claims, said first second portion being integrally moulded with said elongate structural member.

Inventors: GRANT, ALEXANDER
Applicants: GRANT, ALEXANDER
Application year: 1987
Main classification: E05D1
IPC codes: E05D11, E05D7, E05D1, E05D9