Patent Application
20130098124
This invention relates to latching mechanisms, and, more particularly, to a rotary latch for containers such as tool boxes mounted to the bed of a pickup truck.
Rotary latches are routinely used on doors, chests, cabinets and other containers where a lid or door must be retained in a closed and/or locked position. One common type of rotary latch includes a latch plate moveable between a latched and unlatched position. When unlatched, the latch plate may receive a striker pin mounted to the lid of a toolbox, for example, as the lid is moved to a closed position. Once the lid is closed, the latch plate moves to the latched position to capture the striker pin and retain the lid in the closed position. The rotary latch may be provided with a lock to prevent the latch plate from releasing the striker pin except when unlocked.
A number of designs have been proposed in the prior art to move the latch plate from its latched position and allow the striker pin to be released. One approach is disclosed in U.S. Pat. No. 6,973,810 in which a handle mounted to the housing of a rotary latch is pivoted to set in motion a series of components that cooperate to move the latch plate to an unlatched position. In this and similar designs, a first end of the handle is pivotally mounted to the latch housing and its opposite, second end connects to one of the components that function to open the latch plate. The latch plate is opened by moving the second end of the handle to an unlatched position thus pivoting the handle about its first end. However, a substantial amount of force is required to pivot the latch handle because, as noted above, its second end is directly connected to the series of components that cooperate to open the latch plate.
This invention is directed to a rotary latch mechanism for securing the lid of a container in a closed position wherein a mechanical advantage is employed to facilitate latching and unlatching of the latch plate of the rotary latch mechanism with much less force than is required in prior art designs of the type described above.
In one presently preferred embodiment, the latch mechanism includes a latch body and a handle having a first end, and a second end coupled to a pivot pin mounted to the latch body. The pivot pin carries a pivot arm that contacts an actuator which releasably engages a latch plate operative to capture a striker pin, such as from the lid of the truck box, when the lid is closed. The first end of the handle preferably mounts a lock cylinder which is moveable between a locked and unlocked position. With the lock cylinder unlocked, the handle may be grasped and pulled outwardly so that its first end is spaced from the latch body. Such movement of the handle rotates the pivot pin connected to the second end of the handle, which, in turn, causes the pivot arm carried by the pivot pin to engage the actuator and ultimately move the latch plate to an unlatched position to receive, or to release, the striker pin.
Unlike prior art latch mechanisms of the type described above, a mechanical advantage is obtained with the rotary latch of this invention. Pulling the handle outwardly from the latch body is made easier because its first end is not connected to any components that directly or indirectly cause movement of the latch plate. Instead, the handle acts as a lever arm wherein rotation of the pivot pin coupled to the second end of the handle is created by lifting the opposite, first end of the handle. As noted above, rotation of the pivot pin, in turn, sets in motion the components operative to move the latch plate to the unlatched position.
The structure, operation and advantages of the presently preferred embodiment of this invention will become further apparent upon consideration of the following description, taken in conjunction with the accompanying drawings, wherein:
Referring now to the drawings, the rotary latch 8 of this invention comprises a latch body 10 having a center section 12 located between opposed end sections 14 and 16. The center section 12 is formed with a recess 18 to receive the fingers as one grasps a handle 20 which spans the recess 18 and extends between the two end sections 14, 16.
A first end 22 of the handle 20 is formed with a through bore 23 within which a key cylinder 24 is mounted. The first end 22 is beveled so that it engages a correspondingly beveled seat 26 mounted on the front surface 28 of the latch body 10. An opening (not shown) is formed in the latch body 10 through which the key cylinder 24 extends between spaced posts 30 and 32 each connected at one end to the rear surface 34 of the latch body 10. The inner end of the key cylinder 24 is mounted to a locking plate 36 by a bolt 38, and a coil spring 40 extends between the locking plate 36 and the rear surface 34 of the latch body 10. As described in more detail below in connection with a discussion of the operation of the rotary latch 8 of this invention, in response to operation of the key cylinder 24 the locking plate 36 is movable between a locked position shown in
The second end 42 of the handle 20, opposite its first end 22, is beveled to engage a second seat 44 mounted to the end section 16 of latch body 10. The second end 42 of handle 20 is coupled to a pin 46 which is pivotally mounted to an upper bearing 48 and a lower bearing 50 each connected to the rear surface 34 of the latch body 10. For purposes of the present discussion, the terms “upper,” “lower,” “vertically” and “laterally” refer to the orientation of the structures of the rotary latch 8 in the position depicted in the Figs. The pin 46, in turn, is fixed to a pivot arm 52 which is movable with rotation of the pin 46 relative to an actuator 54. As best seen in
A spring (not shown) carried on the shaft 64 biases the latch plate 62 toward an unlatched position, illustrated in
The rotary latch 8 of this invention operates as follows. If the key cylinder 24 is in the locked position depicted in
The rotary latch 8 remains in the position shown in
An important aspect of this invention is the mechanical advantage realized by the handle 20 in setting in motion the operation of pivot arm 52, actuator 54 and latch plate 62 to release the striker pin 63 from the rotary latch 8. As noted above, the first end 22 of handle 20 is pulled outwardly from the front surface 28 of the latch body 10 causing rotation of the pin 46 which is coupled to the opposite, second end 42 of the handle 20. The first end 22 of handle 20 does not directly act on the components that open the rotary latch, e.g. the pivot arm 52, actuator 54 or latch plate 62, but rather the overall length of the handle 20 is used advantageously as a lever arm to rotate pin 46. This construction greatly reduces the effort required to open the rotary latch 8 of this invention, especially compared to prior art arrangements such as described above.
While the invention has been described with reference to a preferred embodiment, it should be understood by those skilled in the art that various changes may be made and equivalents substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
