Theft prevention apparatus
BACKGROUND OF THE INVENTION 
     Present day computer systems include various modules which are coupled together to make up the entire system. As an example, several disk drivers may be coupled together and to a CPU module by a mechanism which also permits uncoupling, and, as a result, portions of such systems may be stolen or just borrowed by a fellow worker. In either case, the removal of a portion of a computer system may cause considerable inconvenience. 
     The present invention provides a simple and efficient theft prevention arrangement for computer systems and the like. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of separated modules of a computer system with which the invention is employed; 
     FIG. 2 is a sectional view of a portion of the apparatus of FIG. 1; 
     FIG. 3 is a sectional view of another portion of the apparatus of FIG. 1; 
     FIG. 4 is a perspective view of portions of the apparatus of FIG. 1 coupled together and including a portion of the apparatus of the invention; 
     FIG. 5 is a perspective view of other apparatus of the invention; and 
     FIG. 6 is the same view as FIG. 4 with the apparatus of the invention shown in FIG. 5 in place. 
    
    
     DESCRIPTION OF THE INVENTION 
     The principles of the invention can be used to couple together substantially any two assemblies or housings for electronic or other apparatus. For purposes of illustration, the invention is used to couple together a disk drive assembly 10 and a central processor unit module (CPU) 40 (FIG. 1). 
     The disk drive assembly 10 comprises one or more disk drive units 30, and one end wall of the assembly comprises a metal plate 50. The CPU module 40 similarly includes an end wall formed by a metal plate 60, to which a coupling plate 80 is rotatably secured at its center 193. Plate 50 is provided with an array of curved openings 90 on a first outer circumference and an array of second smaller inner openings 100 on a smaller inner circumference. 
     The rotatable plate 80, which is used for coupling together the two assemblies 10 and 40, is provided on its free surface, which can be seen in FIG. 1, with a plurality of locking ramps 110 arrayed on a first circumference to match the openings in plate 50. The ramps 110 (FIG. 2) comprise brackets which are secured to the plate 80 at one end 112 and include a first portion 114 which lies generally parallel to but spaced from the plate 80 and an end portion 116 which tapers outwardly away from the main body of the plate 80. 
     A plurality of small wedge-shaped members 120 (FIGS. 1 and 3), known as ejection wedges, are formed on the free surface of the coupling plate 80 and are positioned to align with the openings 100 in plate 50. 
     The coupling plate 80 is provided with a projecting portion 130 which is used as a handle. 
     In operation of the mechanism thus far described, first, the two assemblies 10 and 40 are positioned facing each other with the plate 80 rotated clockwise, in which position, the locking ramps 110 are generally aligned with the apertures 90, and the wedges 120 are aligned with the apertures 100 in plate 50. The two assemblies are brought together and adjusted so that the locking ramps 110 enter their associated apertures 90 in plate 50, and the wedges 120 enter apertures 100, and the plate 80 is rotated counter-clockwise to cause the locking ramps 110 to tightly engage the plate 50 and to lock the two assemblies together. With the parts locked together, the handle 130 is down near the bases 140, 150 of the assemblies, as shown in FIG. 4. 
     To disconnect the assemblies, the handle 130 is pushed upwardly and the assemblies are manipulated to disengage assembly 10 from the coupling plate 80 which remains secured to plate 60 of assembly 40. It is noted that, as the handle 130 is pushed upwardly and the coupling plate 80 rotates with respect to the plate 50, the wedges 120 ride out of the openings 100 in plate 50 and then push against the solid portion of plate 50 and thus assist the separation process. 
     According to the invention, to lock the disk drive assembly 10 and CPU 40 together, the bases 140 and 150 of the housings of the assemblies near their adjacent edges are provided with aligned holes 160, 162, into each of which a locking bracket 170 is inserted. The locking brackets 170 are identical, and they each include a first leg 172 having a hole 174, a second leg 176 which is disposed at a right angle to the first, a third leg 178 which is disposed at a right angle extending rearwardly to leg 176, and finally a short curved leg 180 which extends away from leg 178. 
     In using the brackets 170, they are positioned with the legs 172 adjacent to and facing each other with the holes 178 aligned, and the legs 174 and curved portions 180 are inserted in the holes 160, 162 in the bases 140, 150 of the housings. The parts are arrayed so that the legs 174 contact each other and the legs 170 rest on the walls of the housings in which the holes 160, 162 are formed. A conventional key lock 190 is secured to the legs 172 of the brackets 170, and the lock body lies close to the handle 130 of the coupling plate 80. 
     It is noted that the lock 190 and the locking plate handle 130 provide a complementary function. When the parts are locked together, the handle 130 cannot be moved upwardly toward the lock 190 to disengage the assemblies 10 and 40 because the lock 190 is in the way. If the handle did not operate in this way, that is, if it were not prevented from rotating to separate the assemblies, the assemblies could be separated sufficiently to let the brackets 170 drop out of the holes 160, 162, and the locking mechanism would thus fall off.