Locking device for windows

1. A locking device for windows, which is configured restrict the movement of a window installed in a window frame to allow an anti-crime function to be given to the window, the locking device comprising:

a window side-locking unit joined to a sliding side of the window, the window side-locking unit including an engagement element formed thereon at regular intervals along a sliding direction of the window; and

a window frame side-locking unit directly engaged with the window frame to correspond to the window side-locking unit, so that the window frame side-locking unit is engaged to the window side-locking unit to fix the position of the window,

wherein the window frame side-locking unit comprises:

a stop member configured to be vertically moved in a direction perpendicular to the sliding direction of the window so as to be engaged to or disengaged from the engagement element; and

a manipulation lever configured to be exposed to the indoor side of the window frame to allow a user to vertically move the stop member through manipulation of the manipulation lever,

wherein the stop member of the window frame side-locking unit is installed such that an elastic force is applied to the direction of the window side-locking unit by a spring, so that when the user desires to adjust the opening of the window, he or she turns the manipulation lever to cause the stop member to be moved in an opposite direction to that of the window side-locking unit, and

wherein the stop member of the window frame side-locking unit comprises:

a fixed bar installed at a lower portion of the window frame side-locking unit;

a feed block joined to the fixed bar so as to be slidably moved in the direction of the window side-locking unit, the feed block being supported by the spring inserted into the fixed bar such that the feed block is applied with an elastic force to the direction of the window side-locking unit and is moved in an opposite direction to that of the window side-locking unit by the turning of the manipulation lever; and

a stop bar releasably joined to the feed block and engaged to or disengaged from the engagement element of the window side-locking unit, the stop bar being separately joined to the window frame side-locking unit after the window frame side-locking unit is installed in the window frame.

2. The locking device according to claim 1 , wherein the window side-locking unit comprises a flat plate having a plurality of holes formed thereon at regular intervals along the sliding direction of the window so that the holes serve as the engagement element.

3. The locking device according to claim 1 , wherein the window frame side-locking unit further comprises:

a casing detachably mounted to the window frame such that the manipulation lever is joined to the casing so as to be exposed to the indoor side of the window frame, wherein the fixed bar and the feed block of the stop member are accommodated within the casing;

a rotary shaft rotatably supported within the casing and joined with the manipulation lever; and

a connecting rod rotatably fittingly mounted at one end thereof to the rotary shaft and connected at the other end thereof with the feed block of the stop member, the connecting rod including a guide slot penetratingly formed thereon by a predetermined length along a circumferential direction thereof, wherein a pin mounted on the rotary shaft is fitted into the guide slot so that the connecting rod is rotated by rotation of the rotary shaft while being maintained in a free state on the rotary shaft.