Patent Publication Number: US-6668607-B1

Title: Lock core

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a lock core, particularly to one having a plurality of recessed holes bored in the recessed hollow of an upper lock cover for respectively receiving at least one steel ball therein. Thus, when a burglar employs an electric drill to break and unlock a lock by drilling through the keyhole of the lock, the steel balls in the recessed holes can stop the electric drill from drilling forward, having excellent effect of anti-theft. 
     2. Description of the Prior Art 
     A conventional lock core  1 , as shown in FIG. 1, is composed of a lower lock cover  10 , a lock plate  11  and an upper lock cover  12 . The lower lock cover  10 , the lock plate  11  and the upper lock cover  12  are respectively formed with a curved groove passage  13  matching with one another. The lower lock cover  10  is formed with a recessed hollow  14  at the upper portion and a keyhole  15  at one end. The upper lock cover  12  is bored with a plurality of pinholes  16  in the groove passage  13  for pins  17  to be respectively inserted therein. In assembling, the lock plate  11  is first deposited in the recessed hollow  14  of the lower lock cover  10  and then the upper lock cover  12  is covered on the lock plate  11 , letting the groove passage  13  of the lower lock cover  10 , the plate  11  and the upper lock cover  12  aligned to one another. Lastly, a clasp  18  is engaged in the corresponding clasping holes  19  respectively provided at the opposite ends of the lower and the upper lock cover  10 ,  12  to finish assembly of the lock core. However, such a conventional lock core  1  is easy to be broken by an electric drill, which a burglar employs to drill through the keyhole  15  of the lock. 
     SUMMARY OF THE INVENTION 
     The objective of invention is to offer a lock core able to guard against being broken by an electric drill drilling through the keyhole of a lock. 
     The feature of the invention is that an upper lock cover has its recessed hollow provided with a plurality of recessed holes respectively fitted therein with at least one steel ball. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     This invention will be better understood by referring to the accompanying drawings, wherein: 
     FIG. 1 is an exploded perspective view of a conventional lock core; 
     FIG. 2 is an exploded perspective view of a lock core in the present invention; and, 
     FIG. 3 is cross-sectional view of the lock core in the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of a lock core in the present invention, as shown in FIG. 2, includes a lower lock cover  2 , a lock plate  3  and an upper lock cover  4  combined together. The lower lock cover  2 , the lock plate  3  and the upper lock cover  4  are respectively formed with a curved groove passage  20 ,  30 ,  40  matching with one another. 
     The lower lock cover  2  has a plurality of projections  21  provided at the upper side and a keyhole  22  formed at one end. The keyhole  22  has its inner sidewall bored with a notch  23  fitted therein with an elastic clasp  24  for clasping and holding a key. Further, the lower lock cover  2  is formed with a semi-annular clasping groove  25  around an inner end. 
     The lock plate  3  to be positioned between the lower lock cover  2  and the upper lock cover  4  is bored with plural insert holes  31  matching with the projections  21  of the lower lock cover  2 . 
     The upper lock cover  4  to be assembled on the lower lock cover  2  is formed with a recessed hollow  41  having a plurality of small recesses  42  and recessed holes  43 . The small recesses  42  conform to the projections  21  of the lower lock cover  2 , and the recessed holes  43  are respectively fitted therein with at least one steel ball  5 . The upper lock cover  4  further has a semi-annular clasping groove  44  formed around an inner end to correspond to the clasping groove  25  of the lower lock cover  2 , and a pin recess  45  formed at one edge and plural pin holes  46  provided in the groove passage  40  for lock pins  6  to be respectively inserted therein. 
     In assembling, as shown in FIGS. 2 and 3, the lock plate  3  is positioned on the lower cover  2 , letting the insert holes  31  of the lock plate  3  match with the projections  21  of the lower lock cover  2 . Then, the upper lock cover  4  is covered on the lower lock cover  2 , letting the recessed hollow  41  of the upper cover  4  aligned to the lock plate  3  and the groove passage  20 ,  30 ,  40  of the lower lock cover  2 , the lock plate  3  and the upper lock cover  4  match with one another. Lastly, the lower lock cover  2  and the upper lock cover  4  are fixedly assembled together by means of a clasp  7  tightly engaged in the clasping grooves  25 ,  24  of the lower and the upper lock cover  2 ,  4  to finish assembly of the lock core. Thus, when a burglar employs an electric drill to break and unlock a lock by drilling through the keyhole  22  of the lock, the electric drill will be stopped by the steel balls  5  in the recessed holes  43  of the upper lock cover  4  and in consequence, impossible to keep on drilling forward, having excellent effect of antitheft. 
     While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.