Flush lock for casement window having a low-profile lock handle and method of operating the same

A flush lock for a casement window, said flush lock comprising:

• a lever arm;
• a casing including:
• an upper housing;
• and
• a lower housing including an elongated aperture or slot to accommodate a full range of motion of said lever arm, sidewalls having guide tracks to confine movement of a fork component or an actuator component, and a detent mechanism housing extending from a bottom surface of said lower housing, said detent mechanism housing secured at a bottom end by a cap;
• a restrictor arm pivotally attached at one end to said lever arm;
• and pivotally attached at an opposite end to said lower housing;
• and
• a detent mechanism forming a push-push activation of said lever arm, said detent mechanism including:
• a sleeve being substantially a shell having an internal cavity and internal segments extending axially along a center axis of said sleeve, said internal segments extending radially inwards and being separated by gaps, and extending axially less than a full length of said sleeve, each of said internal segments having a top surface;
• a plunger, configured to be received by said internal cavity of said sleeve, said plunger includes fixed guides extending circumferentially radially outwards about a base of said plunger, said fixed guides slidably interact with said gaps of said sleeve during activation, said plunger includes a bottom or base portion having teeth protruding beyond said bottom or base portion, said teeth configured to form a camming action with a ratchet, rotating said plunger;
• said ratchet having a base portion and a cylindrical stem extending from said base portion, said base portion having an outer diameter larger than an outer diameter of said cylindrical stem, and axially directed keys extending radially outwards from a bottom to a top surface of said base portion, said axially directed keys each having a radially inward segment at said top surface of said base portion, said radially inward segments extending to an outer surface of cylindrical stem, wherein each of said axially directed keys includes an inclined surfaces that is angled axially upwards along a side of said corresponding one of said axially directed keys to a top surface of said radially inward segment, such that said inclined surfaces form a camming action when placed in contact with said teeth of said plunger, thereby rotating said plunger;
• and
• a spring providing a resilient force to said ratchet and said plunger at one end;
• and to said cap at an opposite end, said cap sealing said spring within said detent mechanism housing.

A method of unlocking a flush lock in combination with a casement window, said method comprising:

• providing said flush lock having a lever arm for actuating a fork component associated with a locking tie bar of said casement window, and a detent mechanism configured for push-push activation, said detent mechanism including a sleeve, a plunger, a ratchet, a spring, and a cap, said detent mechanism housed within a detent mechanism housing of a casing of said flush lock;
• pushing said lever arm from an initial position flush with a top surface of an escutcheon that forms part of a top surface of said casing towards said casing and below said top surface of said escutcheon to release said lever arm, wherein said plunger and said ratchet are biased by said spring in a direction towards said lever arm, and wherein the pushing of said lever arm comprises pushing said lever arm in a direction towards said casing and comprises lowering said plunger against said ratchet' such that said plunger rotates relative to said sleeve in a camming action;
• releasing said lever arm, such that said detent mechanism acts on said lever arm to extend said lever arm above said top surface of said escutcheon, exposing said lever arm in an open position away from said escutcheon top surface for grasping by a user;
• and
• rotating said lever arm to an unlocked position to unlock said casement window.

A method of locking a flush lock in combination with a casement window, said method comprising:

• providing said flush lock having a lever arm for actuating a fork component associated with a locking tie bar of said casement window, and a detent mechanism configured for push-push activation, said detent mechanism including a sleeve, a plunger, a ratchet, a spring, and a cap, said detent mechanism housed within a detent mechanism housing of a casing of said flush lock,
• wherein said sleeve includes an internal cavity and internal segments extending axially along a center axis of said sleeve, said internal segments extending radially inwards and being separated by gaps extending axially less than a full length of said sleeve, and said internal segments including a first set of internal segments axially longer than a second set of internal segments, each of said internal segments having a top surface, and
• wherein said plunger includes fixed guides extending circumferentially radially outwards about a base portion of said plunger, said base portion of said plunger further having teeth protruding beyond said base portion and configured to form a camming action with said ratchet, thereby rotating said plunger;
• rotating said lever arm towards said flush lock;
• slidably interacting said fixed guides of said plunger with said gaps of said sleeve;
• pushing said lever arm from an initial position above a top surface of an escutcheon that forms part of a top surface of said casing towards said casing and below said a-top surface of said escutcheon;
• and
• releasing said lever arm, such that said detent mechanism acts on said lever arm to align a top surface of said lever arm with said top surface of said escutcheon, such that said top surface of said lever arm is flush with said top surface of said escutcheon,
• wherein said fixed guides of said plunger are situated on a top surface of said first set of internal segments, such that said plunger raises said lever arm to a level of said top surface of said escutcheon.