Hinges

Abstract

In a lift-off hinge comprising two barrel members and a hinge pin which projects from and co-axially of one barrel member and makes a sliding and rotatable fit within a bore in the other barrel member, the free end of the hinge pin is formed with a cam face which is inclined to the axis of rotation and which engages with a complementary inclined cam face extending in the bore of the said other barrel member.

Description

This invention relates to hinges of the kind known as lift-off hinges which are commonly used for hanging a door upon the vertical stile of a fixed frame.

Existing lift-off hinges may be of one or other of two known types which provide respectively either a parallel movement or a rising and falling movement between the two hinge parts. Normally such lift-off hinges comprise two barrel members and a hinge pin which projects from and co-axially of one barrel and makes a sliding and rotatable fit within a bore in the other barrel member. In a rising and falling lift-off hinge adjacent the end faces of the barrel members are chamfered and inclined at complementary angles to the hinge axis. In a parallel movement hinge such adjacent end faces are parallel.

As a consequence with known types of lift-off hinges it is necessary for manufacturers to provide one set of tools for producing the parallel movement hinge and a different set of tools for producing the rising and falling hinges. This necessity increases tooling costs, and this effectively increases manufacturing costs. Additionally wholesalers and retailers have to stock both types of lift-off hinge thereby increasing the initial expenditure and storage space required.

One object of the present invention is to overcome, or minimize, the foregoing disadvantages by enabling a lift-off hinge to be converted quickly and easily from a rising and falling hinge to a parallel movement hinge and vice versa.

A further problem in connection with known rising and falling lift-off hinges is that metal to metal contact occurs between the chamfered inclined adjacent faces of the two barrel members; also, where wear occurs between the hinge pin and the bore in the barrel member in which the hinge pin is rotatably received. As a consequence of such wear and the complementary nature of the two barrel members, it is not possible to replace only one of the barrel members or the hinge pin when servicing the hinge. In each case the whole hinge has to be replaced which can be most inconvenient insofar as the fitting to the vertical stile of the fixed frame and the door may require filling or further removal of material, and this increases fixing costs.

Accordingly a further object of this invention is to provide a lift-off hinge in which excessive wear is avoided by preventing metal to metal contact between the relatively movable hinge parts. Another object is to provide a lift-off hinge which can easily be repaired or serviced by the use of easily replaceable parts.

This invention consists in a lift-off hinge comprising two barrel members, one barrel member having a hinge pin and the other barrel member having a bore for receiving the hinge pin for relative rotation and slidable movement, said hinge being characterized in that the free end of the hinge pin is formed with a cam face which is inclined to the axis of rotation and which engages with a complementary inclined cam face extending in the bore of said other barrel member.

Accordingly in the invented lift-off hinge the two cam faces serve to vertically displace the one barrel member when relative rotation occurs so as to give the required rising and falling movement to a door when the hinge is in use.

Preferably a cam member is removably seated in the bore of said other barrel and provides said complementary cam face. The cam member may be formed of a low friction material such as nylon or acetal resin to reduce wear, and the cam member may be seated in the bore of said other barrel member for adjustable re-orientation relative to the barrel member.

In an additional feature of this invention, metal to metal contact is prevented between the hinge pin and said other barrel and between the adjacent faces of the two barrel members.

In order that the invention may be clearly understood an exemplary embodiment will now be described with reference to the accompanying drawing wherein:

FIG. 1 is an exploded perspective view of a lift-off hinge in accordance with the invention;

FIG. 2 is a vertical section of the lift-off hinge depicted in FIG. 1 in a lower position corresponding to a `closed position`; and

FIG. 3 is a view similar to FIG. 2 except that the lift-off hinge is in an upper position corresponding to an `open position`.

The exemplary lift-off hinge shown in the accompanying drawing comprises two barrel members 1 and 2. Each barrel member 1, 2 has a cylindrical body 3, 4 respectively, and from each body 3, 4 there extends an integral plate 5, 6 respectively which is for securing respectively, in known manner to a vertical stile of a door frame (not shown) and a door (not shown).

The barrel member 1 which will be uppermost in situ is formed with an integral hinge pin 7 which depends co-axially from the body 3 and is of a smaller diameter than the diameter of the body 3. The free end of the hinge pin is formed with a cam face 8 which extends in a plane inclined substantially at 45.degree. to the longitudinal axis of the hinge pin 7. The lowermost part of the cam face 8 extends on the side of the hinge pin remote from the plate 5, and the uppermost part of the cam face 8 is nearest the plate 5, the cam face 8 being symmetrical about the vertical plane containing the plate 5.

The body 4 of the barrel member 2 has the same external diameter of the body 3 but it is counterbored and the lower end is pierced by a central hole 9.

A flanged sleeve 10 is received and seated in the upper part of the bore. The sleeve 10 is preferably formed of a low friction material such as nylon or acetal resin. The flange 11 extends between the adjacent end faces of the bodies 3 and 4 so as to prevent metal-to-metal contact. The bore of the sleeve 10 is such as to receive the hinge pin 7 for smooth rotation therein.

A cam member 12 is housed in the lower part of the bore in the body 4. The cam member 12 is also preferably formed of a low friction material which may be the same as that utilized for the flanged sleeve 10.

The cam member 12 comprises a cylindrical body of which one end is formed with a square stub 13 having a groove 14 formed therein. The lower end of the bore is provided with a square section recess in which the stub 13 is located and seated. The other end is inclined at 45.degree. to the axis of the body so as to provide a cam face 15 which is complementary to the hinge pin cam face 8. The uppermost edge of the cam face 15 is flattened to provide in situ a substantially horizontal platform 16.

As is shown in FIG. 2, when the hinge is in the `closed position`, the two cam faces 8 and 15 engage with one another over their respective areas and the two plates 5 and 6 are close to one another. When in use the door is opened, the upper barrel member is rotated relative to the lower barrel member into the extreme position shown in FIG. 3. During such opening movement, the cam faces 8 and 15 are relatively displaced causing the upper barrel member to be lifted vertically which raises the door secured thereto. In the initial rotation of the hinge pin, say through the first 90.degree. the maximum vertical movement is obtained, and during subsequent rotation to a maximum of about 180.degree. at the final stage the lowermost part of the cam face 8 rests on the platform 16 so that no further vertical movement is obtained. On closing the door the vertical movement is in the reverse sense.

Now although the exemplary hinge is described as for a flush-fitted left-hand hinge, the relative vertical displacement of the uppermost barrel member may be re-orientated relative to the position of the plates by changing the position in which the cam member 12 is seated in the recess in the lower barrel. This is easily carried out by separating the two barrel members 1 and 2, pushing the cam member upwards from its seating through the hole 9 and relocating the cam member by means of the groove 14.

Additionally, as the cam member 12 is readily removable, the hinge can easily be converted to give an ordinary parallel displacement instead of the rising and falling action herebefore described.

Accordingly, the same hinge barrel members can be utilized to provide two different types of hinge, and this reduces the cost of tooling, manufacture and facilitates the fitting of the hinge.

As will be appreciated, instead of the plates illustrated in the aforedescribed embodiment the barrel members may be provided with other suitable means for securing respectively to a stile and a door. For instance, the barrel members may have integral pegs extending therefrom which are adapted to be secured in situ either by a screw thread or a through bore for receiving a locking pin.

Claims

I claim:

1. A lift-off hinge comprising two-barrel members, a hinge pin mounted on one of said barrel members, a cam face on the free end of said hinge pin and inclined to the pivot axis of the hinge pin, means on the other of said barrel members and defining a bore receiving said hinge pin for relative pivotal movement, a cam member closing said bore and having a cylindrical body of which one free end face is inclined to said pivot axis and constitutes a complementary cam face engaging said first-mentioned cam face, a stub extending from said body oppositely to said complementary cam face, the end wall of said other barrel member having a recess in which said stub is located, and said end wall has an opening through which said stub is accessible for re-orientating or removing said cam member.

2. A lift-off hinge according to claim 1 wherein both of said cam faces are inclined at 45.degree. to said axis of rotation.

3. A lift-off hinge according to claim 2 wherein a flanged sleeve is seated in said bore and the flange thereof extends between the adjacent end faces of said two barrel members.