Push-push latch

Details Push-push latch Push-push latch

2000-11-03

2004-04-13

Sandy, Robert J. (Department: 3677)

Closure fasteners

Keepers

With movable dog, catch or striker

C292S110000, C292S121000, C292S122000, C292S150000, C292SDIG004

Reexamination Certificate

active

06719337

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is a latch wherein latching and unlatching are accomplished by an inward push of a keeper into the latch housing.
2. Description of the Related Art
Although push-push latches have been proposed in the art, none are seen to provide the positive and reliable operation of the push-push latch of the present invention.
An example of a known push-push latch is described in U.S. Pat. No. 4,655,489 issued to Robert Bisbing on Apr. 7, 1987. The push-push latch of Bisbing uses a spring having a portion under compression and a portion in tension. The Bisbing latch is difficult to assemble and requires one side of the latch housing to be removable for assembly. The simplified design of the present invention allows the use of a one piece housing which reduces manufacturing cost.
SUMMARY OF THE INVENTION
The present invention is a latch wherein latching and unlatching are controlled by an inward push by the keeper towards the latch, generally known as a push-push latch.
The latch includes a housing, containing a hook beam, a shuttle opposite the hook beam, and a compression spring, for biasing the shuttle upward within the housing. The latch mates with a corresponding keeper to secure a moving member, such as a door or drawer, to a nonmoving member, such as the frame of the door or drawer. The latch will typically be secured to the nonmoving member, with the keeper secured to the moving member, but the opposite arrangement will work equally well. It should be noted that the following summary refers to a top, bottom, left, right, etc. for simplicity of reference only, and not to imply that the orientation of the latch is critical to its function.
The housing is generally rectangular, and is preferably made of one-piece construction. The housing is in the form of a shell defining a cavity having an interior, and an opening in its top surface. The housing has a pair of opposing openings in its front and back surfaces. A pair of opposing snap legs extends downward and inward into the housing from the top edges of the opposing openings. A second pair of opposing snap legs extends upward and outward from the bottom of the housing's left and right sides, ending with a ridged surface. The front of the housing further has an additional opening on the same side of the housing as the hook beam. A resilient finger extends from the bottom edge of the opening upward and slightly inward. The bottom of the housing also has a ramp located at the bottom rear corner of the interior below the shuttle of the latch and to one side of the spring. The ramp forms an inclined plane which slants upward in back of the spring and shuttle of the latch.
The hook beam is located within the housing, extending from the top opening towards the bottom of the housing. The hook beam includes a top hook for engaging the keeper, described below. The hook includes a flange extending to one side. A small detent boss projects from the side of the hook opposite the flange. The hook beam also includes a stem. The stem includes a central projection which extends outward towards the shuttle and which preferably has a flat top side. The bottom end of the hook beam further includes a pivot, which is preferably a pair of bosses projecting from either side of the bottom end of the hook beam. The pivot bosses of the hook beam are positioned between the inner snap legs and the bottom of the front and back openings. The motion of the bottom end of the hook beam is rather complex. The pivot bosses are constrained within the front and rear openings in the housing. The front and rear openings are elongated and allow the bottom end of the hook beam to translate to the left or right, as well as for the hook beam to pivot about the central axis of the bosses. The left end of the front and rear openings is notched which additionally allows the pivot end of the beam to move up and down when the pivot bosses are positioned at the left end of the front and rear openings. The bottom end of the hook beam also includes a projection, which projects approximately perpendicularly to the left of the hook beam. The projection preferably has a hook shape.
The shuttle is located opposite the top hook. The bottom portion of the shuttle defines a channel for guiding the compression spring, which abuts the bottom of the housing. The top of the shuttle includes a top surface for making contact with the keeper (described later). The top of the shuttle further includes an overhang for making contact with the top side of the central projection of the hook beam. An arm extends outward from one side of the top of the shuttle in the same direction as the overhang, immediately below the flange extending from the hook beam's hook. A skirt extends downward and to the right from the top portion of the shuttle, being dimensioned and configured to push against the perpendicular projection at the bottom of the hook beam, when the hook beam is in the unlatched configuration.
The keeper includes a mounting plate, preferably having an adhesive backing, and a hook. The keeper's hook is dimensioned and configured to push downward on the shuttle's top portion, and to engage the hook beam's top hook.
The latch will typically be installed within a socket. The socket is shaped to correspond with the shape of the housing, to prevent misalignment of the latch. Upon inserting the latch into the socket, the ridges on the outer snap legs will engage the edges of the socket, securing the latch within the socket. The keeper is then inserted into the latch, where it is secured therein as described below. The adhesive backing of the keeper is exposed, and the moving member to be secured by the latch is brought into its closed position, in contact with the adhesive. When the adhesive is dry, the keeper will be secured in the proper position to engage the latch.
The latching and unlatching cycle begins with the hook beam in its upward vertical position, against one side of the housing opposite the shuttle. To actuate the latch, the moving member is moved into its closed position, thereby bringing the keeper and latch together, and inserting the keeper's hook into the latch. The keeper pushes the shuttle toward the bottom of the housing, causing the shuttle's skirt to push against the hook beam's bottom arm, rotating the hook beam's top hook into engagement with the keeper's hook. As the hook beam's top hook rotates, the detent boss near the hooked end of the beam is snapped onto the left side of the resilient finger of the housing thereby ensuring the proper position of the hook beam's top hook for engagement with the keeper's hook. At this point, the user will release pressure on the moving member, allowing the spring to push the shuttle upward, thereby pushing the keeper slightly upward. As the keeper pulls on the top hook of the hook beam, the hook beam is pulled into a vertical position. Proper vertical alignment of the hook beam is insured by the detent boss near the hooked end of the beam, which is constrained from moving back to its original position by the resilient finger of the housing. Continued upward motion of the shuttle is prevented by the keeper hook, which is held by the hooked end of the hook beam and blocks the shuttle from returning to its original position. The latch is now securely latched.
To unlatch the latch, the moving member is again pushed inward, thereby causing the keeper to push the shuttle inward. The overhang of the top portion of the shuttle pushes down on the hook beam's central projection, causing the hook beam to move down. As the hook beam moves down, the perpendicular projection or arm at the bottom of the hook beam contacts the ramp of the housing which creates a reaction force which rotates the top hook and stem of the hook beam away from the hook of the keeper which allows the keeper's hook to exit the latch. As the top hook is rotated away from the hook of the keeper, the detent boss at the top of the stem of the ho

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