Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a release magnet for anti-theft devices for merchandise. 
     2. Description of Prior Art 
     Anti-theft devices, which are pushed through the articles to be secured, are known in commerce, in particular for merchandise, such as textiles, handbags, and the like. When the anti-theft devices are removed without authorization, they damage or at least partially destroy the articles. For example, conventional anti-theft devices consist of a two-piece security body, fastened on clothing when pushed through the clothing. These two parts can only be released if one of the parts, which has automatically clamping locking means, is placed for release into a cup-shaped opening of a magnet. The locking means are thus magnetically actuated, the clamping is released and the two parts can be separated and removed from the material without damaging the material. The release magnets have a housing consisting of a disk-shaped collar which is screwed together with a cylinder. The actual release magnet, a permanent magnet, is clamped in the cylinder and secured from below by means of a plate screwed into the cylinder. All these elements are made of steel. At a top, the release magnet is secured by a press-fitted U-shaped cover made of a light metal or brass. These release magnets are inserted into a through-bore in a table and screwed in from the bottom in such a way that only the collar projects past the surface of the table and rests with an underside on the table top, without a space in between. 
     These release magnets are very expensive, since they have several screwed together parts. For exactly this reason they have no homogeneous surface. The release magnets are difficult to clean and have a tendency to corrode. The magnet is particularly prone to corrosion, since humidity and cleaning agents can penetrate between the cover of light metal or brass and the steel cylinder. Release magnets wherein the releasable security elements meet the magnet directly and come into contact with the magnet are also widely known. This often results in damage, and the highly corrosion-prone magnets are directly exposed to damaging effects from the outside. 
     SUMMARY OF THE INVENTION 
     It is one object of this invention to create a release magnet of the type mentioned which has fewer parts and is therefore cheaper and also is so easy to clean that sanitary conditions are assured and miscellaneous corrosion is prevented to a great degree. 
     This object is attained by this invention as described in the following specification and in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The release magnet for anti-theft devices in accordance with this invention will be described in what follows in connection with the drawings wherein: 
     FIG. 1 is a top view of a release magnet; 
     FIG. 2 is a side view of the release magnet; and 
     FIG. 3 is a vertical cross sectional view of the release magnet. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Only the housing  20  of the release magnet  1  can be seen in the top view of FIG.  1 . The housing  20  has a round collar  21  and a round depression  22  concentrically cut in the housing  20 . The depression  22  corresponds in size to the elements of conventional magnetically releasable anti-theft devices. For releasing such an anti-theft device, it is known to extend the part of the anti-theft device to be released into the depression  22 , whereupon the locking pin on the upper part of the anti-theft device can be pulled out of the released part. 
     The housing  20  is represented in the side view of FIG.  2 . The housing  20  has the collar  21  which, in the state where it is mounted on a table, rests on the table at an underside, wherein the other parts are inside the table itself and are not easily accessible. A first cylindrical holder  26  adjoins the underside of the collar  21  and receives a magnetic force amplifying ring  11 . The underside of the first holder  26  is adjoined by a second cylindrical holder  23 . The cylindrical holder  23  encloses the permanent magnet  10 . Fastening means  27  are arranged laterally next to the second holder  23  and contact the second holder  23  and the first holder  26 . The fastening means  27  are used for fastening the release magnet on a table or the like. The fastening means  27  can be designed as dowel-like receivers for screws. However, many other types of the fastening means  27  are conceivable for fastening the release magnet in a table. 
     FIG. 3 represents the release magnet in cross section A—A as shown in FIG. 1, in a vertical direction. The housing  20  is of one piece and encloses both the permanent magnet  10  and the magnetic force amplifying ring  11  completely and free of gaps. The permanent magnet  10  is located in the second holder  23  and is downwardly covered by a bottom  24 . Toward the top the permanent magnet  10  is also seamlessly covered by a cover  25 . The cover  25  is a bottom for the depression  22 , which is used for receiving corresponding parts of anti-theft devices. The first holder  26  completely surrounds the magnetic force amplifying ring  11 . At an upper end the first holder  26  makes a direct transition into the collar  21 . On its sides, the depression  22  has slightly inwardly inclined flanks, which simultaneously form an inner part of the first holder  26 . In this example the fastening elements are designed as lateral projections on the second holder  23  and have vertical bores for receiving screws. 
     The magnetic force amplifying ring  11  is arranged in the housing  20  above and approximately centered with respect to the permanent magnet  10 . The poles of the magnetic force amplifying ring  11  and of the permanent magnet  10  are arranged in such a way that like poles are located directly opposite each other and adjoining. 
     The manufacture of the release magnet in accordance with this invention preferably takes place by means of a direct, single piece extrusion coating of the permanent magnet  10  and the magnetic force amplifying ring  11 , in a single work step. The magnetic force amplifying ring  11  is at a slight distance from the permanent magnet  10 . Both the permanent magnet  10  and the magnetic force amplifying ring  11  are almost completely enclosed in the material of the housing  20 . This gives further stability to the housing  20  and prevents all undesired direct contact with the magnetic materials. Small exhaust holes can be provided to accommodate the extrusion process, can be arranged in the bottom  24  and can subsequently be closed. It is easily seen that the release magnet in accordance with this invention has no gaps, no threads, or the like. For this reason neither humidity nor cleaning agents can reach either the magnetic force amplifying ring  11  or the permanent magnet  10  which are protected against soiling and corrosion. The plastic housing can be washed. As a flat disk which runs out towards the outside, the collar  21  cannot be grasped by pliers or other tools. It is also not possible to remove the permanent magnet by unscrewing the inner part. Deliberate damage is practically impossible. The release magnets in accordance with this invention can also be embodied with the housing  20  in such a way that they can be erected on a table, screwed or glued on from above or below. Thus the collar  21  can also be formed on the lower end of the release magnet and can have the fastening elements.

Technology Category: 0