Patent Publication Number: US-6981396-B1

Title: Exchangeable lock construction

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a lock construction which is mounted on a door lock and operated by insertion of a key, and more particularly, to an exchangeable lock construction capable of being assembled to and disassembled from the door lock, thereby effectively preventing separation of the lock construction or unlocking of the door lock through the use of various pseudo keys, but not a correct key suitable for the lock construction, for unfair purpose. 
   2. Background of the Related Art 
   Recently, various countermeasures have been taken to prevent unlocking of a door lock for the purpose of criminal acts. As one of them, a lock construction mounted on a door lock is assemblable and disassemblable by an exchangeable key. For example, in case of a door lock for a lodging house, there occasionally occurs a case where a lodger copies a key during lodging, and then, opens the door lock of the corresponding room using the copied key after leaving the lodging house for the purpose of criminal acts. Therefore, to prevent the crime, an owner of the lodging house mounts a door lock with a separable lock construction, and then, exchanges the lock construction with another lock construction of different lodging room, if necessary. 
   However, the above lock construction cannot prevent unlocking by means of pseudo keys for unlocking a lock (keys that a key mechanic uses for unlocking a lock by controlling the inner pins one by one without a correct key to open a door if a user lost the correct key, but they are occasionally used for the purpose of crime), but not the copied key. 
   Meanwhile, there is another countermeasure that has been taken to prevent illegal unlocking of the door lock. That is, a general lock construction, which cannot be separated from the door lock, includes a side waved portion formed on a side of a key to reinforce security, and a slide bar for rotating an inner rolling body or preventing the rotation of the inner rolling body by the side waved portion. 
   As an example of the above lock construction, there is disclosed U.S. Pat. No. 6,477,876 in which as shown in  FIG. 6 , a side waved portion  101  is formed on a side of a key  100 , a plurality of rectangular slide pins  120  are mounted in an inner rolling body  110 , the rectangular slide pins formed at one side with grooves  121  horizontally arranged by the side waved portion  101 , and a slide bar  130  is centrally pushed when the inner rolling body  110  is rotated by the arrangement of the grooves  121 . 
   Therefore, such a lock construction can be unlocked only when an upper waved portion  102  of the key  100  aligns associated elements of the lock construction and the side waved portion  101  of the key  100  also aligns other associated elements of the lock construction, and hence can further increase security as compared with a general lock construction. 
   There has been an attempt to apply the security reinforcing structure by virtue of the slide bar to a door lock with an exchangeable lock construction. However, for an exchangeable lock structure (structure in which a tubular operation body is locked to the inner periphery of a fixed body or unlocked from the inner periphery while being rotated when a key is inserted and turned) by virtue of an tubular operation body among various constitutional means for exchanging the locking construction, because the tubular operation body surrounds the rolling body, the slide bar cannot be mounted. As a result, the exchangeable lock construction with the tubular operation body is weaker in security than other exchangeable lock constructions. 
   The present invention is aimed at combining the exchangeable lock construction using the tubular operation body with a structure in which the slide bar is operated by a side waved portion of a key, so as to further reinforce security and reliability of such an exchangeable lock construction. Furthermore, the present invention is aimed at reinforcing security by virtue of operation of the slide bar and preventing damage of the lock construction by means of a drilling machine. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention has been devised in order to solve the above problems occurring in the prior art. 
   An object of the present invention is to provide a lock construction, in which a lock construction structure using an tubular operation body is combined with a security function by virtue of a slide bar operated by a side waved portion of a key, thereby further increasing security and preventing random operation of the slide bar in spite of a little error through a more accurate operation of the slide bar. 
   In more detail, the lock construction according to the present invention includes an outer fixed body which is fixed after being inserted into a door lock, and a main body assembly inserted into the fixed body or separated from the fixed body. The main body assembly can be separated from the fixed body by a key manufactured suitably for replacement of the lock construction. 
   The main body assembly includes a casing, an tubular operation body mounted inside the casing for allowing the main body assembly to be assembled to or disassembled from the fixed body by a function of the key, and a rolling body for locking or unlocking the door lock while rotating by the turning of the key. 
   The casing, the tubular operation body and the inner rolling body respectively are formed with pin holes passing through their center areas for inserting pins aligned by the key thereto. 
   Particularly, a slide bar operated by a side waved portion of the key is mounted in the rolling body. The tubular operation body has an elongated slide operation slit formed thereon and the casing has a locking groove formed on the inner periphery thereof for operation of the slide bar. 
   Furthermore, a slide pin for restricting the operation of the slide bar includes a plurality of auxiliary grooves for making the operation of the slide bar impossible in spite of a little inaccurate alignment of the slide pins, and the slide bar is formed at the front end thereof with a recess to be locked in the auxiliary grooves of the slide pin. 
   By such an arrangement, the lock construction according to the present invention can be assembled and disassembled like the conventional separable lock constructions, and additionally provide a security function by virtue of the slide bar. 
   Moreover, since the slide bar of the present invention includes the recess formed at the front end thereof and the slide pin includes the auxiliary grooves formed above and below a receiving groove formed thereon, when a pseudo key, namely, a copied key is inserted into the lock construction and the inner rolling body is rotated in a state where the slide pins are not aligned precisely, the upper and lower sharpened portions of the recess of the slide bar are locked in the auxiliary grooves of the slide pin, so that the slide bar cannot be inserted into the receiving groove of the slide pin and the door lock is thus not unlocked. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which: 
       FIG. 1  is an exploded perspective view schematically illustrating a lock construction according to a preferred embodiment of the present invention; 
       FIG. 2  is an exploded perspective view in detail illustrating a lock construction according to a preferred embodiment of the present invention; 
       FIG. 3  is a cross-sectional view of an insertion hole of a fixed body according to the present invention; 
       FIGS. 4   a  and  4   b  are cross-sectional views showing states before and after a slide bar is operated; 
       FIGS. 5   a  and  5   b  are cross-sectional views showing states before and after a door lock is unlocked through the lock construction according to the present invention; and 
       FIG. 6  is an exploded perspective view showing essential components of a conventional lock construction. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
     FIGS. 1 to 5  show a preferred embodiment of the present invention. 
   As shown in  FIG. 1 , a lock construction  1  includes an outer fixed body  2  fixed to a door lock after being inserted into the door lock, and a main body assembly  3  inserted into the fixed body  2  or separated from the fixed body  2 . A key  4  is inserted into a key hole  31  centrally formed in a rolling body  30  of the main body assembly  3 . 
   In the above, a key for unlocking the door lock by rotating the rolling body and a key for separating the main body assembly  3  from the fixed body  2  by operating a tubular operation body are needed. 
   The main body assembly  3  is contoured to forcedly fit into an insertion hole  2   a  formed in the fixed body  2 . The insertion hole  2   a  and the main body assembly  3  respectively are in a shape in which two circles are partially overlapped. 
   Hereinafter, referring to  FIG. 2 , the main body assembly  3  will be described in more detail. The main body assembly  3  includes a casing  10  a casing contoured to properly fit into the insertion hole  2   a  of the fixed body and having an opening. 
   The casing  10 , the tubular operation body  20  and the rolling body  30  respectively have a plurality of pin holes  12 ,  22  and  32  communicating with one another. Well-known pins  5 , sleeves  5   a  of different heights, and springs  5   b  are inserted into the pin holes, and then, aligned by an upper waved portion  4   a  of a key  4  in such a manner as to be rotated when the key  4  is inserted into the lock construction  1 . 
   The tubular operation body  20  has a retaining protrusion  21  formed thereon and is accommodated in the casing  10  in a rotatable state at a predetermined angle. When the tubular operation body  20  is rotated in a side direction, the retaining protrusion  21  is exposed to a retaining opening  11  of the casing  10  and locked by the inner periphery of the insertion hole  2   a , so that the main body assembly  3  is not separated from the insertion hole  2   a . When the tubular operation body  20  is rotated in the opposite direction to the above rotating direction, the retaining protrusion  21  is unlocked from the inner periphery of the insertion hole  2   a  and the main body assembly  3  can be separated from the fixed body  2 . 
   As shown in  FIG. 3 , the entrance side of the insertion hole  2   a  of the fixed body  2  is in the form where two circles are partially overlapped, but the inside of the insertion hole  2   a  is in the form that two circles are connected in a straight line, so that the retaining protrusion  21  can be locked to the insertion hole  2   a.    
   The inner rolling body  30  includes a slide bar  33 , which is similar to what has been described in the “background of the related art” part, and which is supported by a spring  33   b . A slide pin  34  for restricting operation of the slide bar  33  includes a receiving groove  34   a  formed thereon in such a manner as to be located at different positions, for inserting the slide bar  33  thereinto and heights thereon and a plurality of auxiliary grooves  34   b  formed above and below the receiving groove  34   a . The slide bar  33  includes a recess  33   a  formed at the inner side end thereof in the form of a ‘&lt;’ shape. 
   The tubular operation body  20  includes an elongated operation slit  23  formed at a side thereof for allowing the slide bar  33  to slidably pass therethrough in such a manner as to be located at the same position as the slide bar  33  when being assembled, and the casing  10  includes a locking groove  13  formed on the inner peripheral portion thereof for locking the outer side end of the slide bar  33  therein. 
   The cover  50  includes a damage-preventing piece  51  inserted into the inner periphery just above the position where the rolling body  30  is assembled. The damage-preventing piece  51  is greatly improved in strength with a thermal treatment so as to prevent cutting. 
   Reference numeral  35  designates a ring for assembly, and numeral  4   b  designates a side waved portion of the key. 
   The function of the lock construction  1  according to the present invention will be described hereinafter in more detail. 
   First, a function for separating the main body assembly  3  from the fixed body  2  referring to  FIGS. 4   a  and  4   b  will now be described with reference to  FIGS. 4   a  and  4   b.    
   When the key  4  manufactured for the purpose of separation of the main body assembly  3  from the outer fixed body  2  is inserted into the key hole  31 , a plurality of the slide pins  34  are aligned by the side waved portion  4   b  of the key  4 , so that the receiving grooves  34   a  of the slide pins  34  are aligned in a straight line. Therefore, the inner side end of the slide bar  33  can be inserted into the receiving grooves  34   a.    
   Moreover, the pins  5  and sleeves  5   a  are aligned by the upper waved portion  4   a  of the key  4 . At this time, the pins  5  and the sleeves  5   a  are aligned between the casing  10  and the tubular operation body  20 , so that the tubular operation body  20  can be moved in a state where the casing  10  is fixed. 
   By the above operation, when the rolling body  30  is rotated by the key  4  in a clockwise direction, the slide bar  33  is pushed away from the locking groove  13  formed on the inner periphery of the casing  10 , while being rotated together with the rolling body  30  in a state where the inner side end of the slide bar  33  is inserted into the receiving grooves  34   a  of the slide pins  34 . 
   Therefore, because the retaining protrusion  21  of the tubular operation body  20  is escaped from the retaining opening  111  of the casing  10  toward the interior space of the casing when the tubular operation body  20  is rotated, the entire main body assembly  3  can be separated from the insertion hole  2   a  of the fixed body  2 . 
   When the key  4  is turned in a counterclockwise direction in a state where the main body assembly  3  is completely inserted into the insertion hole  2   a  of the fixed body  2 , the retaining protrusion  21  is exposed outwardly from the outer periphery of the casing  10  through the retaining opening  11  of the casing  10  and locked to the inner periphery of the insertion hole  2   a.    
   Hereinafter, the operation for unlocking the door lock by virtue of a function of the key  4  will be described with reference to  FIGS. 5   a  and  5   b.    
   When the key  4  manufactured for the purpose of locking and unlocking a door lock is inserted into the key hole  31 , the slide pins  34  are aligned like the above principle for separating the main body assembly  3  from the fixed body  2 , and at the same time, the pins  5  and the sleeves  5   a  are aligned by the upper waved portion  4   a  of the key  4 . At this time, the pins  5  and the sleeves  5   a  are aligned between the rolling body  30  and the tubular operation body  20 , but not between the casing  10  and the tubular operation body  20 . It means that the tubular operation body  20  is not moved in engagement with the casing  10  even though the rolling body  30  is rotated. 
   Therefore, when the key  4  is turned in a clockwise direction, the slide bar  33  is escaped from the elongated operation slit  23  of the tubular operation body  20  and deeply inserted into the receiving grooves  34   a , and only the rolling body  30  is completely rotated to unlock the door lock. 
   The present invention can prevent an error which may occurs in the course of inserting the slide bar  33  into the receiving grooves  34   a  of the slide pins  34 . To this end, the slide bar  33  includes the recess  33   a  formed at the inner side end thereof in the form of a ‘&lt;’ shape, and the slide pin  34  includes a plurality of auxiliary grooves  34   b  formed above and below the receiving groove  34   a . Therefore, in the case where a user tries to unlock the door lock with a copied key or a pseudo key, or to separate the main body assembly  3  for unfair purpose, when the rolling body  30  is rotated in a state where the slide pins  34  are not aligned precisely, the upper and lower sharpened portions of the receiving groove  33   a  of the slide bar  33  are locked in the auxiliary grooves  34   b  of the slide pins  34 , so that the slide bar  33  cannot be slid and the door lock is not unlocked. 
   In the prior art lock construction, even though the receiving grooves of the slide pins  34  are aligned a little inaccurately, when the rolling body is rotated strongly, the slide bar is forcedly slid into the receiving grooves. Therefore, the present invention can further reinforce security of the lock construction as compared with the conventional lock construction. 
   According to the present invention, since the damage-preventing piece  51  greatly improved in strength with a thermal treatment is inserted into the inner periphery of the cover  50  where the pins  5  are aligned, any damage of the main body assembly  3  by means of the drilling machine can be prevented. 
   The forgoing embodiment is merely exemplary and is not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.