Abstract:
A lock bolt structure having a center of one end of a casing being formed with an intresting perforation for a shaft to extend through. Multiple axially extending lateral ribs are formed on the circumference of the core shaft, which has a cross-section with a shape corresponding to the intesecting perforation. Two lock bolts having guide channels on opposite faces are disposed on two sides of the intersecting perforation. The outer ends of the bolts are formed with hook sections which extend symmetrically outwards. The lateral ribs are slidably inserted in the guide channels to integrally connect the lock bolts with the core shaft. The cross-shaped cross-section of the core shaft provides enhanced torque strength for the lock bolt structure to avoid damage to the lock by external twisting force.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is related to a lock bolt structure of steel cable lock, and more particularly to a lock bolt structure including two separately movable lock bolts for enhancing torque strength of the lock bolt structure. The lock bolt structure is protected from being damaged by external twisting force so as to achieve a better burglarproof effect. 
     Taiwanese Patent Publication Nos. 370147, 413259, 424840, 435561 disclose various steel cable locks. The lock bolt structures of such steel cable locks can be substantially divided into two kinds as follows: 
     First, a fixed lock bolt is disposed on the casing in cooperation with a movable lock bolt. The movable lock bolt can be extended from the fixed lock bolt and engaged in a hole formed on an article to achieve a locking effect (such as Publication Nos. 370147 and 424840). Second, two relatively movable lock plates can be expanded to engage in a hole formed on an article to be locked so as to achieve a locking effect (such as Publication Nos. 413259 and 435561 ). The above kinds of lock bolt structures are both characterized in that the fixed lock bolt and movable lock bolt (or two movable lock bolts ) are separated from each other. Such lock bolt structures have a certain strength against an external force applied onto the lock bolts to draw the lock bolts out of the hole of the article. However, in the case the lock body is forcedly turned, the lock bolts tend to be twisted, deformed and bent. As a result, the lock bolts can be easily drawn out of the hole of the article. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the present invention to provide a lock bolt structure of steel cable lock. Two lock bolts are disposed at one end section of the casing of the lock. The lock bolts can be oppositely pivotally rotated to close or expand. The outer ends of the lock bolts are formed with hook sections which symmetrically outward extends. The lock bolts are formed with guide channels on opposite faces. A core shaft extends between the lock bolts. The circumference of the core shaft is formed with multiple axially extending lateral ribs. Two lateral ribs are slidably inserted in the guide channels of the lock bolts to integrally connect the lock bolts with the core shaft. The core shaft can be extended or retracted by a lock core disposed in the casing so as to contract or expand the lock bolts. The core shaft has a cross-shaped cross-section. The casing is formed with a corresponding cross-shaped perforation. The core shaft is passed through the cross-shaped perforation to provide enhanced torque strength for the lock bolt structure to avoid damage of the lock by external twisting force. 
    
    
     The present invention can be best understood through the following description and accompanying drawings wherein: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective exploded view of the present invention; 
     FIG. 2 is a partially assembled view of the present invention; 
     FIG. 3 is a perspective assembled view of the present invention; 
     FIG. 4 is a sectional view showing the locking operation of the present invention in one state; 
     FIG. 5 is a sectional view showing the locking operation of the present invention in another state; and 
     FIG. 6 shows the application of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to FIG.  1 . The present invention includes a casing  1 , a lock core  2 , a driving block  3 , two lock bolts  4  and a core shaft  5 . The casing  1  is composed of a base seat  11  and an upper cover  12 . A projecting post  111  is disposed on a middle portion of inner side of the base seat  11 . The surface of the upper cover  12  is formed with multiple numeral windows  121 . When the base seat  11  and the upper cover  12  are mated with each other, an end section of the base seat  11  and an end section of the upper cover  12  snugly clamp and embrace an inner stop board  13 . A shift bar  15  is axially slidably disposed on the circumference of the casing  1 . One end of the shift bar  15  has a push section  151  extending into the casing  1 . A press block  152  is formed on one side of the push section  151  and outward protrudes from the casing  1 . The center of the inner stop board  13  is formed with a substantially cross-shaped perforation  131 . Two through holes  132  are formed on two sides of the perforation  131 . An inner face of a front cap  14  is connected with outer face of the inner stop board  13 . The center of the front cap  14  is formed with a through hole  142 . Two parallel slots  141  are formed on the inner face of the front cap  14  on two sides of the through hole  142 . Multiple numeral wheels  21  are side by side arranged on the circumference of the lock core  2  for controlling the unlocking/locking operation of the lock core  2 . One end section of the lock core  2  is connected with a driving board  22  having a transverse extending insertion channel  221 . A restoring spring  23  is disposed between the driving board  22  and the numeral wheels  21  for resiliently restoring the driving board  22 . The middle portion of the driving block  3  is formed with an insertion slit  32  and an insertion recess  34  extending in parallel to the insertion slit  32 . An engaging board  33  having a notch  331  on bottom side is inserted and located in the insertion slit  32 . One end section of the driving block  3  is formed with a boss section  31  having a central through hole  311  communicating with the insertion slit  32 . A pivoted plate  36  is pivotally fitted on the projecting post  111  in the base seat  11 . One end of the pivoted plate  36  extends into the insertion recess  34 . The other end of the pivoted plate  36  extends into an insertion slit  351  of middle portion of a linking board  35 . One end of the linking board  35  is formed with a projecting section  352  for inserting into the insertion channel  221  of the driving board  22 . A middle portion of each lock bolt  4  is formed with a shaft section  41 . One end of the lock bolt  4  is formed with an obliquely extending rear end section  42 . The other end of the lock bolt  4  is formed with an outward extending hook section  43 . The lock bolt  4  is formed with a longitudinally extending guide channel  44  on one side opposite to the hook section  43 . The core shaft  5  is an elongated member. One end of the core shaft  5  is formed with a gradually widened expansion section  51 . The other end of the core shaft  5  is formed with an annular groove  52 . The circumference of the core shaft  5  is formed with multiple axially extending ribs  53 , whereby the core shaft  5  has a cross-section with a shape corresponding to the shape of the cross-shaped perforation  131 . 
     Please refer to FIGS. 2 and 3. When assembled, the lock core  2  is received in the casing  1 . The numeral wheels  21  are partially exposed to outer side through the numeral windows  121  for a user to shift the numeral wheels  21  for controlling the lock core  2 . The push section  151  of the shift bar  15  positioned between the base seat  11  and the upper cover  12  presses outer side of the driving board  22 . The driving board  22  is coupled with the linking board  35  via the insertion channel  221  and the projecting section  352 . The linking board  35  clamps and fits on one end section of the pivoted plate  36 . The other end section of the pivoted plate  36  is drivingly engaged with the driving block  3 . With the guide channels  44  opposite to each other, the shaft sections  41  of the two lock bolts  4  are respectively fitted into the slots  141  of the front cap  14 . The hook sections  43  pass through the through hole  142  and extend outward. The front cap  14  is connected with the outer face of the inner stop board  13  and the rear end sections  42  of the lock bolts  4  extend into the through holes  132  of the inner stop board  13 . The end of the core shaft  5  with the annular groove  52  passes through the cross-shaped perforation  131  of the inner stop board  13  and extends into the through hole  311  of the boss section  31 . Via the notch  331 , the engaging board  33  inserted in the insertion slit  32  fits into the annular groove  52  to clamp the core shaft  5 . Accordingly, the core shaft  5  is drivingly coupled with the driving block  3 . When the core shaft  5  is located in its true position, two lateral ribs  53  of the core shaft  5  extend into the guide channels  44  of the lock bolts  4 . 
     After assembled, a steel cable  6  is clamped and connected with the casing  1  to form a complete steel cable lock. 
     FIGS. 4,  5  and  6  show the operation of the present invention. In use, in the case that a user shifts the respective numeral wheels  21  to correct position, the user can press the press block  152  to push the shift bar  15 . At this time, the push section  151  presses and retracts the driving board  22 . Via the linking board  35 , the driving board  22  pulls one end of the pivoted plate  36 , whereby the other end thereof reversely forward pushes the driving block  3 . At this time, the boss section  31  of the driving block  3  pushes the lock bolts  4  between the rear end sections  42  thereof. Accordingly, the other ends of the lock bolts  4  are closed toward each other. (At this time, the core shaft  5  is driven by the driving block  3  and the expansion section  51  protrudes outward and the lateral ribs  53  are totally accommodated in the guide channels  44  as shown in FIG. 4.) Under such circumstance, the user can extend the hook sections  43  of the lock bolts  4  into a lock bolt hole  71  formed on the housing  7  of an article to be locked. (FIG. 6 shows a notebook-type computer which is to be locked.) After the hook sections  43  of the lock bolts  4  are inserted and located in the lock bolt hole  71  of the housing  7 , the user releases the press block  152  and the restoring spring  23  resiliently restores the driving board  22  to its home position. At this time, the linking board  35  synchronously forward pushes one end of the pivoted plate  36 , whereby the other end of the pivoted plate  36  pulls the driving block  3 . At this time, the expansion section  51  of the core shaft  5  is synchronously pulled to slide inward between the two lock bolts  4  and abut against the hook sections  43  at outer ends thereof. Under such circumstance, the hook sections  43  are laterally extended to hook inner side of the lock bolt hole  71  of the housing  7  as shown in FIG.  5 . Then, the numeral wheels  21  are randomly shifted to form a locked state. 
     The above operation can be reversely performed to draw the lock bolts  4  out of the lock bolt hole  71  of the housing  7  to unlock the article. 
     According to the above arrangement, the torque strength of the lock bolts of the steel cable lock is enhanced to avoid damage of the steel cable lock due to external twisting force. 
     The above embodiment is only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiment can be made without departing from the spirit of the present invention.