US 3431590 A
Description (OCR text may contain errors)
March 11, 1969 L. ANDERSON 3,431,590
HINGE Filed Dec. 19, 1.966
5d Lnderuom 7 VJ? U omg United States 4 Claims ABSTRACT OF THE DISCLOSURE A hinge in which a metallic knuckle on one leaf is interleaved between two metallic knuckles on the other leaf. Non-metallic cylindrical bushings are inserted into the ends of the middle knuckle and circular flanges are formed on the outer ends of the bushings to prevent metal-to-metal contact between the knuckles. A pivot pin is inserted through each outer knuckle and projects into the adjacent bushing. In order to prevent a build-up of static electricity, an electrical connection is established between the two hinge leaves and this is accomplished by a spring disposed within the middle knuckle and abutting the inner ends of the pivot pins.
This invention relates to a hinge for use in supporting a door on a frame to swing about a fixed axis between open and closed positions and more particularly to hinges having leaves with interleaved knuckles or curls which are separated from each other by a hearing or bushing of a non-metallic material.
The primary object of the invention is to provide a hinge of the above character with an electrically conductive path between otherwise electrically isolated hinge leaf members to ground the hinge leaf for supporting a door and thereby eliminating the danger of a static electrical discharge from the door.
Another object of the invention is to provide a hinge of the above character with a low cost, metal connection between hinge leaves which is hidden from view and requires no redesign or modification of the hinge.
A more detailed object of the invention is to provide a simple and inexpensive metal spring in the knuckle of one hinge leaf for contacting a pivot pin which makes metal to metal contact with the other hingle leaf thereby establishing an electrically conductive path between the hinge leaves.
Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- FIGURE 1 is a fragmentary perspective view of a door supported on a frame by a hinge embodying the novel features of the present invention.
FIG. 2 is a partial sectional and plan view of the hinge.
FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2.
FIG. 4 is a sectional view taken along line 44 in FIG. 3.
FIG. 5 is a sectional view taken along line 55 in FIG. 3.
FIG. 6 is a perspective of a spring for inserting into a hinge knuckle.
For purposes of illustration, the present invention is shown in the drawings embodied in a hinge 10 of the kind disclosed in US. Patent No. 3,015,126 for use in mounting a door 11 on a frame 12 to turn about a vertical axis between an open and closed position. The illustrated hinge 10 is a type commonly known as a butt hinge and is utilized to mount a flush type door, that is, a door ice which, when closed, lies in the same plane as the frame. Such hinges include two leaves or wings, a frame leaf 13 and a door leaf 14, both of which extend inwardly between the edges of the door 11 and the frame 12 and which are pinned together to turn relative to each other about a vertical axis.
The leaves 13 and 14 are formed from metal sheets or plates and include fiat portions 15 which lie along the edge of the door 11 and of the frame 12 respectively and are secured to these members as by screws 16. In order to join the leaves 13 and 14 together, interfitting knuckles 17 and 18 are formed on one edge of the flat portions 15, the door leaf having a single knuckle 18 located between and in line with a pair of spaced knuckles 17 on the frame leaf (FIG. 3). The hinge is mounted by inserting the fiat portions 15 between the edges of the door 11 and the frame 12 with the outer periphery of the knuckles 17 and 18 adjacent the outer face of the door and the frame. When the hinge 10 is used with a door and frame of hollow, box-like sheet metal construction as illustrated on the drawings, the flat portions 15 project through slots 19 formed in the face of the door and of the frame and extend along the inner side of the edge of the door and of the frame. The screws 16 are countersunk and extend through the edges and are threaded into the fiat portions 15.
The two leaves 13 and 14 are joined together by a pivot pin 20 which is received in a bore 21 extending through the knuckles 17 and 18 and which has a head 22 on one end to abut the outer end of the knuckle 17. Herein, two such pins 20 are utilized, one inserted into each end of the bore 21. To reduce friction and wear, the surfaces of the leaves 13 and 14 which, would rub together as the door is swung open or closed are separated by bearings 23. These bearings comprise cylindrical inserts of a suitable bearing material such as nylon or the like and are adapted to be received in the bore 21 in the knuckle 18 on the door leaf 14. A radical flange 24 integral with one end of the bearing extends across the end of the knuckle 18 to separate it from the adjacent knuckle 17 on the frame leaf. Two such inserts are used, one inserted in each end of the bore 21 in the knuckle 18 and each has an inside diameter adapted to receive the pivot pin 20.
To prevent the hooking of clothes on the pivot pin, its head 22 is sloped outwardly and downwardly from the door affording a generally bullet shaped head. An inwardly directed vertical finger 26 is formed on the head and is positioned in the space or crack between the door and the frame (FIG. 2.) without being in contact with either the frame or the door. The head of the pivot pin terminates in an annular shoulder 28 from which extends downwardly an integral cylindrical portion 29 which is serrated and has an outside diameter slightly larger than the inside diameter of the bore 21 in the knuckle 17. When the pin is forced into the bore of the knuckle 18, the serrations bite into the knuckle and thereby hold the pin against turning relative to the knuckle. The serrations establish a metal to metal contact between the frame leaf knuckle 18 and the metal pivot pin 20.
Extending downwardly from the serrated portion of the pivot pin 20 and integrally connected with the latter is a cylindrical portion 30 of a reduced diameter which is sized to fit in the bore 31 of a cylindrical sleeve 32 of the bearing 23. The inserted end 34 of the pivot pin 20 terminates slightly beyond the inner ends of the bushings 23. The cylindrical sleeve of the bushing separates and isolates the inserted portion 30 of the pivot pin from metal to metal contact with the Surface of the bore 21 in the door knuckle 18 and the radical flange 24 on the head of the bushing prevents metal to metal contact between the frame knuckles 17 and the interleaved door knuckle 18. Thus, the hinge leaf 14 is electrically isolated from metal to metal contact with the pivot pin and from metal to metal contact with the frame leaf 13.
In a number of installations, there is the probability of a buildup of an explosive atmosphere which may be ignited by a static electrical discharge. Where a possibility of an explosive atmosphere is present, a danger exists in use of hinges in which one leaf is isolated from electrically conductive contact from the other because the static electrical charge buildup on the door leaf cannot be dissipated by conduction to the frame leaf and thereby to ground. The buildup of a static charge on the door may result in a discharge and an explosion.
The present invention contemplates a novel hinge construction which permits the use of non-conductive bushings with good bearing characteristics and, at the same time, to provide an electrical path for the discharge of static electricity. Accordingly, electrical static charges on the door are conducted from the door hinge leaf to the frame hinge leaf by means of a metal spring 36 disposed in contact with a knuckle of one leaf and a pivot pin which is in contact with the knuckles of the other hinge leaf. Herein, any electrical charge on the door is conducted through the central knuckle 18 of the door leaf 14 to the spring 36 disposed in the latter and engaging the pivot pins which are in metal to metal contact with the knuckles 17 of the frame leaf 13.
In the present instance, a small barrel or ball shaped spring 36 is disposed medially of the bore 21 of the door knuckle 18 and between the facing ends of the bushings 23. The diameter of the spring, when freely expanded, is larger than the diameter of the bore of the door knuckle so that when the spring is forced into the knuckle, the sides of the spring are biased into metal to metal contact with the knuckle at a plurality of points of contact. The inserted ends 34 of the pivot pins 20 engage and compress the spring between their ends to establish a good metal to metal contact between the coils of the spring and the ends of the pivot pins. The small resilient force exerted by the spring on the pivot pins in a vertical direction is insufiicient to force the pins from the knuckles but is sufiicient to assure a good and sustaining contact with the hinge pins. As the door swings between open and closed positions, the center knuckle 18 turns relative to the knuckles 17 and pins 20, but a good metal to metal contact is maintained between the coils of the spring and the knuckle 18.
From the foregoing, it will seem that a spring may be readily inserted and assembled in a hinge and affords a low cost connection without requiring the redesign or the minimum of modification of a commercially acceptable door hinge. With door hinges of the other construction, the spring shape may be varied particularly where only a single hinge pin is employed rather than two hinge pins as disclosed herein.
I claim as my invention:
1. A hinge for hanging a door on a frame, said hinge having, in combination, a first leaf member formed of metal and having a portion for laying against the frame, integral knuckles formed and spaced along a vertical edge of the portion, a second leaf member formed of metal and having a portion for laying against the door, an integral knuckle on said second leaf member extending along a vertical edge of the portion and interleaved with the spaced knuckles on said first leaf member, said knuckles having alined vertical holes, two cylindrical bushings of a non-metallic material each with a central bore and each disposed in the hole of said knuckle of said second leaf member, a flange on each of the bushings extending radially between the interleaved knuckles to separate them from contact with one another, metallic pins projecting into said holes in said spaced knuckles and projecting into the bores of the bushings to join the leaf members for pivoting relative to one another, said pins being in metal to metal contact with said spaced knuckles and a metallic spring disposed in the knuckle of the second leaf member and extending into contact with the ends of said pins to complete a discharge path for static electricity between the leaf members.
2. The combination of claim 1 in which said spring is a generally spherical compression spring extending transversely of the hole in the knuckle on said second leaf member, the normal length of said Spring being greater than the diameter of said hole and the diameter of the spring being at least as great as the spacing between said pins whereby the spring constitutes an electrical connection between the pins and the knuckle on said second leaf member.
3. A hinge for hanging a door on a frame, said hinge having, in combination, a first leaf member formed of metal and having a fiat portion for laying against the frame, an integral knuckle formed along a vertical edge of the fiat portion, a second leaf member formed of metal and having a flat portion for laying against the door, an integral knuckle on said second leaf member extending along a vertical edge of the flat portion and interleaved with the knuckle on said first leaf member, said knuckles having alined vertical holes, a cylindrical bushing of a non-metallic material having a central bore and disposed in a hole of at least one of said knuckles, a flange on the bushing extending radially between the interleaved knuckles to separate them from contact with one another, a metallic pin projecting into said holes and through the bore of the bushing to join the leaf members for pivoting relative to one another, said pin being in metal to metal contact with a knuckle of one leaf member and a metallic spring disposed in a knuckle of the other leaf member and extending into contact with said pin to complete a discharge path for static electricit between the leaf members.
4. A hinge for hanging a door on a frame, said hinge having, in combination, first and second leaf members formed of metal for attachment to the door and the frame respectively, integrally formed knuckles formed on each leaf member and interleaved with the knuckle on the other leaf member, said knuckles having alined bores through which extends a pivot axis for swinging the door, a bushing of a non-metallic material inserted into a bore of one of the knuckles and having a portion extending between the knuckles to separate them from contact with one another, said bushing having a bore co-axial with the bore of said knuckles, a metal pivot pin projecting into the bores of the knuckles and the bore of said bushing and having metal to metal contact with one of said knuckles, said bushing spacing said pin against metal to metal contact with the surface of the bore of the other knuckle, and means disposed in said last mentioned knuckle to establish an electrically conductive path from such knuckle to the pivot pin.
References Cited UNITED STATES PATENTS 12/1925 Larson 16134 1/1943 Ibach 16-176 9/ 1959 Schneider 16l68 1/ 1962 Ahlgren 16169 12/1962 Heyer l6168 BOBBY R. GAY, Primary Examiner.
US. Cl. X.R.