1. Field of the Invention
The present invention relates generally to a latch mechanism for securing sliding doors or windows, and more particularly to a latch mechanism which applies forces along two orthogonal axes simultaneously so as to secure the window or door within its associated jamb and improve its relative seal therewith.
2. Cross-Reference to Related Patents
To the extent that disclosures of U.S. Pat. No. 4,976,066 issued on Dec. 11, 1990, to Plummer et al. are necessary for understanding this invention, they are herein incorporated by reference.
3. Description of Related Technology
Numerous mechanisms have been devised to facilitate securing a window, door, or other movable closure panel while permitting the closure member to be readily reopened as needed. A number of such devices have recognized the advantages of dual motion that can be achieved by latching mechanisms which include both rotational and translational components.
For example, U.S. Pat. No. 261,998, issued to Carson, discloses a sash holder in which a cylinder having a spiral groove is rotated adjacent to a plate having an outwardly projecting stud which engages the spiral groove. The plate is mounted on the window frame, while the rotating cylinder is mounted on the sash. As the cylinder is rotated, the stud engages and imparts forces to the cylinder, causing the cylinder to translate along its longitudinal axis, thereby locking the window sash in place.
U.S. Pat. No. 1,286,857, issued to Fischer et al., discloses a door latch having a conventional appearing doorknob mounted on the door. However, rather than rotating the doorknob to release the latch, a small finger plate is placed in the center of the doorknob which is connected to a shaft passing through the door which engages the latch. A spiral rib on the longitudinal shaft causes the shaft to rotate, and thereby release the latch, as the finger plate is pressed.
U.S. Pat. No. 2,128,405, issued to Eastman, discloses a window sealing arrangement utilizing two members which pivot about orthogonal axes. One of the members is a handle having a cam-shaped slot which engages a projection which forms a part of the other pivoted member. When the handle with the cam-shaped slot is rotated, the cam-shaped slot deflects the projection so as to cause the second rotating member to pivot about its axis, thereby engaging or releasing a specially designed trough in a window sash.
U.S. Pat. No. 3,179,454, issued to Mummendey, discloses a sash locking arrangement which permits a sash to be locked at intermediate positions along the window frame. A pair of inclined surfaces define a spiral groove in which a finger travels, the finger being attached to a rotatable shaft. The inclined surfaces are rigidly attached to a handle which may be moved parallel to the longitudinal axis of the rotating shaft.
U.S. Pat. No. 3,560,037, issued to Crain, discloses a latching element which is translated by an actuator having a guide member which slides within an aperture in the surface of the latching element and along first and second camming members located on either side of the guide members. The first and second extensions on the latching element flange slidably engage sloping surfaces of the first and second camming members, resulting in translation of latching element in the direction normal to the displacement of the actuator.
U.S. Pat. No. 4,679,835, issued to Weinerman et al., discloses a cabinet latch having a passage formed through the body along a center axis, and opens through forward and rearward end regions of the body. A primary operating element is journaled for rotation within the forward end region of the body passage, and a shank that has a portion which projects from the rearward end region of the body passage carries a pawl. A half turn rotation of the primary operating element in one direction of rotation causes the pawl to move in sequence by rotating a quarter turn about the center axis from an unlatched position to a latched position and by translating axially along the center axis from the latched position to a latched clamp position. A cylindrical element having a spiral groove is responsible for the translational movement.
None of such prior art structures adequately address the dual security and weathertightness seal problems encountered with actual sliding window or door installations having one or a plurality of moving members. When a sliding window or door is in its closed position, a latching device ideally should press the window or door toward its associated frame jambs in two directions. First, the window or door panel should be forced along the horizontal sliding line of movement for the panel, away from its associated window or door panels so that the window or door panel members seat properly along the extreme ends or side jambs of the frame. In addition, the window or door members must be drawn together in a second, horizontal direction orthogonal to the direction of sliding movement of the window or door, so that weather stripping or other sealing material is uniformly engaged by the window or door panel surfaces when the panels are secured in a closed, locked position. Ideally, operation of such a latch should be by a simple one-stroke movement which is easily accomplished by hand. Such operator motion would generally comprise either a simple linear or arcuate stroke of a handle or a rotational twist of an operator knob. Since the desired forces on the window or door panels ultimately require primarily translational movements, what is required is a latching device which will convert the initial operator initiated movement into translational movement along two orthogonal horizontal directions. The present invention provides such an operator mechanism that is simple to operate, requires little operator effort yet results in superior sealing engagement of the sliding window or door panels within their associated frames.