Claims:
What I claim is
1. A hinge comprising two hinge members and a pin, each hinge member including:
2. The invention claimed in claim 1, in which said one arm is substantially parallel with the plate element adjacent said straight edge.
3. The invention claimed in claim 2, in which said straight edge is oblique to the plane of the plate element.
4. The invention claimed in claim 3, in which the plane of obliquity defines an angle of 135° with the plate element surface closest to said ledge.
5. The invention claimed in claim 1, in which each hinge knuckle has its internal U-shaped recess dimensioned to snugly enclose said pin.
6. The invention claimed in claim 3, in which each hinge knuckle has its internal U-shaped recess dimensioned to snugly enclose said pin.
7. The invention claimed in claim 2, in which the straight edge of one hinge member is spaced from but closely adjacent the hinge knuckle of the other hinge member.
8. The invention claimed in claim 7, in which the straight edge of each plate element is oblique to the plane of the respective plate element, the plane of obliquity defining an angle of about 135° with the plate element surface closest to the respective ledge.
Description:
This invention relates generally to hinges, and has to do particularly with a hinge construction of which the knuckles do not form closed loops, thereby permitting the knuckles and the plate elements to be molded integrally in a single operation.
Open knuckle hinges have been described in the prior art, particularly in U.S. Pat. No. 2,766,901, Sunko, entitled "Hinge" and issued Oct. 16, 1956. However, a serious disadvantage of prior art open-knuckle hinges, as exemplified by U.S. Pat. No. 2,766,901, relates to the fact that some means must be provided to ensure that the pin does not fall out of the knuckles when the open portions of all knuckles are aligned. In the Sunko patent, washers are provided for this purpose, but such a provision requires additional parts that can break or malfunction, and of course additional expense.
In view of the above disadvantage of the prior art structures, it is an object of this invention to provide an open-knuckle hinge construction designed to prevent the hinge plates from reaching a mutual orientation in which the knuckle openings are aligned, thereby ensuring that the hinge pin will always remain in place without the necessity for additional members such as washers.
Accordingly, this invention provides a hinge member adapted to cooperate with another similar hinge member to define a hinge, the hinge member comprising: a plate element having a straight edge, and at least one hinge knuckle extending integrally from the straight edge to define substantially a U-shape of which one arm is contiguous with the plate element and of which the other arm terminates in a ledge extending away from said one arm.
This invention further provides a hinge comprising two hinge members and a pin, each hinge member including: a plate element having a straight edge, and at least one hinge knuckle extending integrally from the straight edge to define a substantially U-shaped section of which one arm is contiguous with the plate element and of which the other arm terminates in a ledge extending away from said one arm, the two hinge members hinged to each other about said pin which passes through the crook of the U-shaped sections, the said other arms of the knuckles of the plate elements all lying to one side of both plate elements when the latter extend away from each other.
One embodiment of this invention is illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:
FIG. 1 is a partly broken away perspective view of the hinge structure of this invention; and
FIGS. 2, 3 and 4 are axial sectional views taken along the line 2--2 in FIG. 1 with the different parts assembled together, showing three mutual angulations of the hinge parts.
Attention is first directed to FIG. 1, in which a hinge structure generally indicated at 10 is seen to include a first hinge member 12 and a second hinge member 13. Each hinge member 12, 13 includes a plate element 14 having a straight edge 15 from which two hinge knuckles 16 integrally extend. While the particular embodiment shown includes two hinge knuckles on each hinge member, it will be appreciated from what follows that the invention does not concern itself with the number of hinge knuckles, but rather with their sectional profile. Thus, any number of hinge knuckles, including a single hinge knuckle, could be provided on each of the hinge members 12 and 13.
Although not essential to this invention, the longitudinal dimension of all of the hinge knuckles in the embodiment shown is the same, and the spacing between two adjacent hinge knuckles on a single hinge member is slightly greater than the longitudinal dimension of a single knuckle. This permits the knuckles of the two hinge membes 12 and 13 to be "interlaced" in the usual manner for a hinge. Again, these dimensional criteria are not essential. The only requisite is that the knuckles and the spaces between adjacent knuckles be dimensioned such that the usual "interlacing" can take place between the two hinge members 12 and 13.
It will be seen from all of the accompanying figures that each hinge knuckle extending away from its respective straight edge 15 defines a U-shaped section 18 of which one arm 19 is contiguous with and parallel to its respective plate element 14, and of which the other arm 21 terminates in a ledge 24 which extends away from the said one arm 19 in a direction substantially perpendicular to the said one arm 19.
Furthermore, the straight edge 15 is oblique to the plane of its respective plate element 14, the plane of obliquity 26 (FIG. 3) defining an obtuse angle α with the surface 28 of the plate element 14, the surface 28 being that which is closest to the ledge 24. The obtuse angle α shown in FIG. 3 for the obliquity of the straight edge 15 is approximately 135° (thus, the slope would normally be defined as a 45°slope) although this precise angle is not critical. The only purpose for the obliquity of the edge 15 is to provide a surface contact rather than an edge contact with the outer, rounded surface 29 of the adjacent hinge knuckle, whenever the plate elements 14 are moved toward one another in the FIG. 3 configuration. If one visualizes the knuckle of the lower plate element 14 moving up to contact the upper oblique edge 15, it will be seen that the edge 15 will have tangential contact with the outer surface 29 of the knuckle. By contrast, if the edge 15 were at right angles to the major plane of the plate element 14, then upward movement of the lower knuckle would engage the rightward boundary of the upper edge 15 in FIG. 3, which would be essentially a corner contact. This would cause wear of the edge, and possible binding, both of which are undesirable.
From the foregoing discussion, however, it will be appreciated that the particular slope of the edge 15 is to some extent dependent upon the relative thicknesses of the plate 14 and the U-shaped channel between the two arms 19 and 21 of the U-shaped knuckle. If the U-shaped channel of the knuckle were considerably greater in diameter than the thickness of the plate element 14, then the obliquity of the edge 15 would have to be increased so that the angle α were greater than 135°, in order to ensure tangential contact rather than corner contact.
Extending through all knuckles of both hinge members 12 and 13 is a hinge pin 30 adapted to fit snugly but slidably within the U-shaped knuckle 16. The pin 30 must be inserted longitudinally, and cannot be slipped into the hinges laterally for reasons which will become clear from the following discussion.
Particular attention is now directed to FIGS. 2, 3 and 4, with the help of which will be discussed that property of the hinge structure which ensures that the pin 30, once in place, is incapable of being removed laterally, i.e. in a direction normal to its main axis. FIGS. 2 and 4 show the limit positions for the two hinge members 12 and 13. FIG. 4 shows a limit positions in which the ledge 24 of each knuckle 16 abuts the surface 28 of the other plate element 14. The plate elements 14 cannot close to a smaller acute angle than that shown in FIG. 4 without breaking or rupturing the ledges 24. It will be appreciated that, in the absence of the ledges 24, it would be possible tb bring the plate elements 14 closer together to a parallel orientation, in which the U-shaped channels in all of the knuckles 16 of both plate elements 14 would be aligned, thereby permitting the pin 30 to fall out or be taken out of the knuckle in a lateral direction. This is undesirable, and therefore the ledges 24 are provided to ensure that it does not happen.
If it is now imagined that the plate elements 14 in the FIG. 4 position are opened out to the coplanar position shown in FIG. 3, it will be quite obvious that it is impossible to remove pin 30 other than longitudinally, because the two plate elements 14 cannot be moved toward each other beyond a very small amount determined by the tolerance (distance) between the outer surface 29 of each knuckle and the adjacent edge 15.
Moving the plate elements 14 further to the FIG. 2 position will cause the hinge structure to reach the other limit, in which the actute angle boundary 32 of each edge 15 abuts the surface 34 of the opposite plate element 14.
It will be appreciated that the hinge members 13 and 14 of the hinge structure disclosed herein can be molded integrally, including the knuckles 16, from a wide variety of thermoplastic and other substances.