US 2727772 A
Description (OCR text may contain errors)
Dec. 20, 1955 A. w. HAMILTON 2,727,772
ELECTROMAGNETIC LOCK Filed Nov. 5, 1953 A/exabdar W Hamil/on INVENTOR.
- BY "fl -M United States Patent ELECTROMAGNETIC LOCK Alexander W. Hamilton, Hopewell Township, Washington County, Pa.
Application November 5, 1953, Serial No. 390,292
1 Claim. (Cl. 292-444) This invention relates to a magnetic lock and more specifically provides a magnetic lock for use in conjunction with closures such as car doors, bus emergency doors, house doors and windows or the like.
An object of this invention is to provide a magnetic lock having an electromagnetic coil surrounding a core for attracting a block or abutment of magnetic material on the door or closure.
Another object of this invention is to provide a magnetic lock wherein the abutment or block is spring loaded will become subsequently apparent reside in the details 1 of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:
Figure 1 is a top plan view of the magnetic lock of this invention in operative position between a door closure and a door frame;
Figure 2 is a longitudinal, vertical section taken substantially along the section line 2-2 of Figure 1 showing the details of construction of the magnetic lock;
Figure 3 is a transverse, vertical section taken substantially along section line 3-3 of Figure 2 showing details of the retraction spring for the abutment block; and,
Figure 4 is an end elevation view looking at the magnetic coil.
Referring now specifically to the drawings, it will be seen that the numeral generally designates the magnetic lock of this invention for use in retaining a closure 12 in closed relation in a closure frame 14.
The magnetic lock 10 includes a coil 16 mounted upon an end washer 18 and surrounding a core 20 of magnetic material. The electric coil and wire 16 is covered with successive windings of insulating tape 22 for protecting the coil wires making up the coil 16. The end washer 18 is mounted in the door frame 14 by suitable fastening members 24 and attaching lugs 26 which are secured to the end washer 18. A ground wire 28 is used to ground the coil 16 to the door frame and an electrical supply wire 30 is connected to an electrical source 32 through a switch 34 which in this instance is mounted upon the dashboard 36 of an automobile.
As shown in Figure 2, the metallic core 20 has a portion extending beyond the confines of the end washer 18 and the core 20 is welded or brazed to the washer 18 wherein the core 20 is stationary in relation to the coil 16.
2,727,772 Patented Dec. 20, 1955 Now referring specifically to the left hand portion of Figure 3 it will be seen that a cylindrical member 38 having an outwardly projecting flange 40 secured to the door 12 by suitable fastening means 42 with the cylindrical portion 38 extending through an aperture in a portion of the door 12 wherein the tubular portion 38 is recessed into the interior of the door 12. The cylindrical or tubular portion 38 has an inwardly extending flange 44 partially enclosing the end of the tubular member 38 and a screw threaded plug 46 is inserted into the other end of the tubular member 38 thereby enclosing the tubular member 38 thereby forming a socket member. An adjustment screw 48 is threadedly engageable with a threaded aperture in the plug 46 and extends into the bottom of the tubular member 38 for a purpose described hereinafter. A bolt or rod member 50 is slidably positioned in the tubular member 38 and is engaged by the inwardly extending flange 44 for guiding movement thereof. A screw threaded washer 52 is secured to the inner end of the rod 50 and closely and slidably engages the interior of the tubular member 38. The inner end of the rod 50 includes an indented portion 54 for engaging the adjusting screw 48. A coil spring 56 is disposed between the flange 44 and the washer 52 for urging the rod 58 inwardly of the tubular member 38. An enlarged head or abutment 58 is secured to the outer end of the rod and includes a socket or recessed portion 60 for engaging the projecting end of the core 20 when the magnetic lock is energized.
It will be understood that when the door 12 is closed and the electric coil 16 energized, the core 20 will attract the head 58 which is of magnetic material thereby engaging the end of the core 20 in the recessed portion 60 and maintaining the door 12 in closed position.
From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readilyoccur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claim.
What is claimed as new is as follows:
An electromagnetic lock for securing a door in closed position in a frame, said lock including: an electromagnet mounted in the frame, said electromagnet comprising a winding and a fixed core projecting therefrom, a cylinder mounted in the door and having an opening in one end, a removable screw plug closing the other end of said cylinder, a bolt mounted for longitudinal reciprocation in the cylinder in spaced, concentric relation thereto and extending slidably through the opening, said bolt being operable to projected position by the electromagnet and comprising a socketed head on its outer end for the reception of the core, a washer threaded on the inner end portion of the bolt and slidable in the cylinder, a coil spring encircling the bolt and engaged with the washer for retracting said bolt, and a screw threaded for adjustment through the plug and engageable with the inner end of the bolt for limiting the movement of said bolt under the influence of the coil spring.
References Cited in the file of this patent UNITED STATES PATENTS 1,958,940 Cavanaugh et al May 15, 1934 2,219,186 Hornfeck Oct. 22, 1940 2,659,114 Anderson et al; Nov. 17, 1953