US 3896404 A
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United States Patent [191 4/1974 Suska 335/205 Peterson July 22, 1975 MAGNETIC SWITCH HINGE Primary Examiner-Harold Broome  Inventor: Francis C. Peterson, St. Louis a g or FumuGrlavely Lleder County, Mo. m a
 Assignee: C. Hager & Sons Hinge Manufacturing Company, St. Louis,  ABSTRACT Mo. A hinge has two leaves held together with a hinge pin and each leaf is provided with a recess opening out of  Filed 1974 the back face thereof. A magnet is completely con- [2l] Appl. No.: 439,132 tained within the recess on the one leaf, while a magnetic reed switch is completely contained within the I recess of the other leaf. When the hinge is closed the 8 fi e g dz magnet actuates the magnetic reed switch, but not  i 200/61 07 when the hinge is open, so that it is possible to mainy tain surveillance over a door from a remote location. Both the magnet and the switch are completely con-  References Cited cealed when the door is either opened or closed so v UNITED STATES PATENTS that it isimpossible to detect their presence or to ,852 tamper with them. No special preparation of the jamb or door is required to install the hinge.
9 Claims, 5 Drawing Figures MAGNETIC SWITCH HINGE BACKGROUND OF THE INVENTION This invention relates in general to hinges, and more particularly to a hinge which will actuate a switch when opened and closed.
Hinges provided with switches capable of being actuated as the hinge opens and closes have heretofore been employed to maintain surveillance over doors located at critical locations in buildings. The switches, however, are exposed on the hinge when the door is opened and therefore someone can tamper with them to render them ineffective. Moreover, their presence is readily known so that people contemplating unauthorized access to such critical areas will choose some other opening to force an entry.
SUMMARY OF THE INVENTION One of the principal objects of the present invention is to provide a hinge capable of actuating a concealed switch as it is opened and closed. Another object is to provide a hinge of the type stated in which the switch is actuated by a magnet. A further object is to provide a hinge of the type stated in which the magnet and switch are completely concealed when the hinge is installed. An additional object is to provide a hinge of the type stated which may be installed on a door and door frame without any special preparation to the door or frame to accommodate the switch and magnet. These and other objects and advantages will become apparent hereinafter.
The present invention resides in a hinge having two leaves, one of which carries a magnet and the other a switch capable of being actuated by the magnet. Both the switch and magnet are completely concealed by ,their respective leaves when the hinge is installed. The invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed.
DESCRIPTION OF THE DRAWINGS In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur:
FIG. 1 is an elevational view of the, hinge in its open position and showing the front faces of the hinge leaves;
FIG. 2 is an elevational view of the hinge in its open position and showing the back faces of the hinge leaves; FIG. 3 is a longitudinal sectional view of the hinge in its closed position;
FIG. 4 is a transverse sectional view of the hinge taken along lines 44 of FIG. 3; and
FIG. 5 is an exploded perspective view of the hinge.
DETAILED DESCRIPTION Referring now to the drawings, A designates a hinge which serves the usual purpose of supporting a door on a door frame and further forms part of a security system for maintaining surveillance over the door.
The hinge A includes two leaves 2 and 4 having rolled knuckles 6. The knuckles 6 of the leaf 2 are offset axially from the knucles 6 of the leaf 4 and further fit between the knuckles 6 on the leaf 4 so that all of the knuckles 6 will align or have the same axis. Fitted through the aligned knuckles 6 is a hinge pin 8 which holds the leaves 2 and 4 together, yet lets the leaf 4 swing relative to the leaf 2 about the axis of the pin 8. The leaves 2 and 4 are provided with holes 10 for receiving screws with countersunk heads. The hinge leaf 2 fits into a mortise in the hinge jamb of the door frame and is secured thereto by screws which extend through the holes 10. The hinge leaf 4 fits into a mortise in the side edge of the door and is secured to the door by the screws which pass through the screw holes 10. Hence, the exposed or front faces of the two leaves 2 and 4 are generally flush with the surface of the jamb and the side surface of the door, respectively.
The hinge leaf 4 is formed from a suitable nonferrous metal or other material which does not easily conduct a magnetic flux. Brass is ideally suited for this purpose. The leaf 4 is provided with a recess 20 (FIG. 5) which opens out of its back face, that is the face presented toward the door, the recess 20 being located in the area which is not obstructed by the screw holes 10. The recess 20 does not distort or otherwise affect the opposite or exposed surface of the leaf 4 so that its presence is not discernible when the leaf is mounted in the mortise of the door (FIG. 1 The recess 20 may be any desirable configuration, but circular is preferred since it is easily machined with a simple end mill cutter. The recess 20 receives a disk-shaped magnet 22 (FIGS. 2-5) which is flat on both ends and substantially fills the recess 22. The axial dimension of the magnet 22 is approximately the same as the depth of the recess 22 so that the back face of the magnet 22 lies flush with the back face of the hinge leaf 2. In any event, the magnet 22 should not project beyond the back face of the leaf, and therefore, no special preparation of the door is required to accommodate the magnet 22. The ferrous disk which forms the magnet 22 is magnetized such that the poles of the magnet 22 are at the flat end surfaces and not along the circular periphery. Otherwise, the magnet 22 will be degaussed, that is rendered ineffective, when the hinge A is installed on a steel door and steel door frame. The magnet 22 is retained in the recess 20 by a suitable adhesive.
The other hinge leaf 2 is likewise formed from asuitable non-ferrous material such as brass which does not easily conduct magnetic flux. That portion of the leaf 2 which is not obstructed by screw holes 10 is provided with an elongated recess 24 (FIG. 5) which opens out of the back face thereof, that is the face presented toward the hinge jamb. The recess 24 is not discernible from the front face of the leaf 2 (FIG. I) so that when the hinge A is installed in the mortise of the jamb, it is impossible from mere visual observation to detect the recess 24. The longitudinal axis of the recess 24 is parallel to the hinge pin 8 and when the hinge A is closed the center of the recess 24 for the leaf 4 is located directly opposite from the center of the recess 20 located in the leaf 2 (FIGS. 3 and 4). The recess 24 contains a magnetic reed switch 26 which is actually a glass tube 28 sealed at both ends and containing a pair of overlapping metallic reeds 30. Each reed 30 is connected to a terminal wire 32 (FIG. 5), and the terminal wires 32 project through and beyond the ends of the tube 28 where they are soldered or otherwise connected to lead wires 34 extending from the leaf 2. Normally, the switch 26 does not conduct an electric current. However, when the switch 26 is brought into a properly oriented magnetic field, the switch 26 will conduct electricity so as to complete a circuit between the lead wires 34. Magnetic reed switches are standard items of commerce.
The magnetic reed switch 26 is positioned in the elongated recess 24 such that it is generally opposite to the magnet 22 when the hinge A is closed and such that the flat surfaces of the overlapping reeds 30 within it are parallel to the major surfaces of the leaf 4. Hence, the flat surfaces of the reeds 30 are parallel to the flat end surfaces of the magnet 22 when the hinge A is closed. Moreover, the diameter of the tube 28 is less than the depth of the elongated recess 24, while the length of the tube 28 is substantially less than the length of the recess 24. Hence, the switch 26 is housed completely within the recess 24 and does not project outwardly past the back face of the leaf 4 so that no special preparation of the hinge jamb is necessary in order to accommodate the switch 26.
That portion of the elongated recess 24 which is not occupied by the switch 26 is filled with a non-ferrous substance 36 capable of being cast such as paraffin wax so that the switch 26 is in effect embedded in the substance 36 (FIGS. 2-4).
Opposite the point where the lead wires leave the elongated recess 24, the hinge jamb of the door frame is provided with a hole to accommodate the lead wires 34. The lead wires 34 extend through the wall and are connected to an alarm at a remote location.
In use, the hinge A enables security personnel at a remote location to maintain surveillance over the door which is supported by the hinge A. In particular, when the door is closed, the hinge A is likewise closed, that is the leaves 2 and 4 are together (FIGS. 3 and 4), and in that position the magnet 22 is located opposite from and close to the magnet reed switch 26. Indeed, the location of the switch 26 and magnet 22 are such that the magnet field of the magnet 22 will keep the switch 22 closed. However, when the door opened, the leaves 2 and 4 move apart and the switch 26 moves out of the magnet field for the magnet 22. When this occurs, the switch 26 breaks the circuit through it and this break in the circuit triggers the alarm at the remote location so that security personnel will know that an unauthorized entry has occurred at the door. During normal working hours the alarm is deactivated so that it is not triggered each time the door is opened.
Since neither the magnetic reed switch 26 nor the magnet 22 is visible when the hinge A is installed on a door and door frame, it is impossible for one to detect the presence of the switch 26 and magnet 22 or to tamper with them to render them ineffective. Also,
both the magnet 22 and the switch 26 are recessed completely in their respective leaves 4 and 2, and consequently no special preparation of the hinge jamb or door is required to install the hinge A.
It has been found that when the hinge A is installed in a steel door frame and door, the steel tends to amplify the magnetic field on the magnet 22 such that it is even more effective.
This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.
What is claimed is:
1. A hinge comprising: first and second generally flat hinge leaves, each leaf being provided with a recess extends only partially through the. leaf with an integral portion of the leaf extending beyond the recess so that the opposite face of the leaf is not disruptedand the recess is invisible at that opposite face, means connecting the hinge leaves to enable them to swing relative to each other; a magnet contained substantially entirely within the recess in the first leaf and creating a magnetic field, and a switch contained substantially entirely within the recess of the second leaf, the switch containing overlapping elongated reeds, the longitudinal axes of which are substantially parallel to the faces of the second leaf, and being sensitive to the magnetic field created by the magnet, the magnet and switch being positioned in their respective leaves such that the magnet will acuate the switch and change the condition thereof in response to swinging movement of the one hinge leaf relative to the other hinge leaf.
2. A hinge according to claim 1 wherein the leaves swing relative to each other between open and closed positions and have front faces which face each other when the leaves are in the closed position, each leaf also having a back face on the opposite side thereof from the front face, the recesses of the leaves opening out of the back faces, whereby the recesses,
the magnet, and the switch are not visible from the front faces of the leaves.
3. A hinge according to claim 1 wherein the leaves are made from a nonferrous metal.
4. A hinge according to claim 2 wherein a surface of the magnet is flush with back face of the first leaf.
5. A hinge according to claim 2 wherein the magnet has end faces which are generally parallel to the major surfaces of the first leaf, and the poles of the magnet are at the end faces.
6. A hinge according to claim 2 wherein the magnet is disk-shaped and has end faces which are generally parallel to the major surface areas of the first leaf, the poles of the magnet being at the end faces.
7. A hinge comprising: first and second leaves, each having front and back faces and recesses which open out of the back faces thereof, means connecting the leaves to enable one leaf to pivot relative to the other leaf about a hinge axis between closed and open positions, the front faces of the leaves being located opposite and adjacent to each other when the leaves are in their closed position and being spread apart when the leaves are in their open positions, a magnet contained wholly within the recess of the first leaf, a switch contained wholly within the recess of the second leaf and having overlapping elongated reeds,'the longitudinal axes of which are substantially parallel to the faces of the second leaf, the switch being sensitive to a magnetic field and being'positioned such that the magnet actuates it and changes its condition as the leaves move relative to each other from their open position to their closed position.
8. A hinge according to claim 7 wherein the recess in the first leaf is cylindrical with the axis of the recess being perpendicular to the front and back faces of the first leaf; wherein the magnet is cylindrical with its thickness being substantiallyless than its diameter, the magnet having an end face located substantially flush with the back face of the first leaf.
A hinge according to claim 7 wherein the reeds are parallel to the faces of the leaf in which the switch is contained.