Electricity: circuit makers and breakers – Electric switch details – Latches
Reexamination Certificate
2001-07-06
2004-05-04
Lee, K. (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Latches
C200S320000, C200S050010
Reexamination Certificate
active
06730867
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is a latch for actuation with both an electric motor and manually.
2. Description of the Related Art
Latch assemblies are relied on in many applications for securing items, such as panels, together. For example, containers, cabinets, closets, compartments and the like may be secured with a latch. An important use for latches is in the automotive field, where there is a desire and need to access automotive compartments, such as, for example, the trunk or passenger compartments of vehicles, as well as interior compartments such as a glove box.
Various latches for panel closures have been employed where one of the panels such as a swinging door or the like is to be fastened or secured to a stationary panel or compartment body. The prior art devices generally utilize a locking member which is spring-loaded externally by one or more separately provided torsion springs. For example, some prior art devices rely upon a lock which comprises rigid metal parts and requires additional biasing members for operation of the assembly. It has been increasingly more important and desirable to provide remote features for operation of latch mechanisms which permits a user to operate the latch from a location remote of that at which the latch is installed. For example, automobile latches often rely on the use of remote devices to open and close door locks, for example, using infrared, radio, or other wireless transmission modes. In addition, vehicle trunks often are provided so that they can be unlocked by remote means to permit the raising or opening of a panel.
In furnishing remote latching mechanisms, it must be taken into account that in some instances remote means may have failures, such as, for example, due to a loss of power supply (especially where electronic circuitry is employed). It is therefore also desirable to provide additional or secondary latching capabilities in order that the latch can be locked or opened manually, should the remote mechanism fail. In some instances, capped openings are provided in the vicinity of the latch which can permit a user to access the latch to open it should the remote mechanism not be operable. However, where security is concerned, it is not practical to provide an easy means for gaining an ability to open a latch. In these instances, complex mechanisms have been employed.
It is desirable to provide a latch which can be utilized both, by a remote locking mechanism and a key operated mechanism, and furthermore, where both the remote and the key operation can be used alternately as desired by the user. That is, it is desirable to have a latch with a locking capability where either a remote locking mechanism or a manual (key type) mechanism can be used to lock or unlock the latch, regardless of which one had previously been used.
The present invention provides a novel ratcheting pawl latch with the ability to lock and unlock the latch with remote and key operated mechanisms.
SUMMARY OF THE INVENTION
The present invention is a latch that may be operated either by an electric motor, possibly remotely, or manually. The latch includes a lockplug housing, a motor housing, a lockplug, a lockplug driver, a locking disk, a pawl, and a pair of roller switches.
The pawl includes a pair of arms and a locking disk engagement tooth. The pawl pivots between a latched and unlatched position, and is spring-biased towards its unlatched position. The pawl is dimensioned and configured to secure a wire keeper between its two arms.
The locking disk is pivotally secured between the lockplug housing and the motor housing. The locking disk defines a bearing surface around its circumference, which further defines a window dimensioned and configured to permit passage of the pawl, and a pair of cutouts. The locking disk pivots between a locked position and an open position, defining an unlocked range of positions therebetween. The locking disk is spring-biased away from the open position, but is not spring-biased in either the locked position or the unlocked range of positions. In the locked and unlocked positions, the edge of the locking disk abuts the locking disk engagement tooth of the pawl, thereby securing the pawl in its latched position. When the locking disk is rotated to the unlocked position, the window is aligned with the pawl, allowing the pawl to rotate to its unlatched position. The locking disk will then abut the pawl's locking disk engagement tooth, preventing the locking disk from rotating out of the locked position.
One side of the locking disk engages a gearbox, which in turn engages a motor. The motor is preferably a 12-volt DC motor, but is not limited to this type. The DC motor may be controlled by any of several means, including a programmable logic controller, a dashboard mounted switch, and/or a remote switch. The opposite side of the locking disk engages the lockplug driver.
The lockplug and lockplug driver turn as a single unit within the lockplug housing. The lockplug is spring-biased towards a central position. The lockplug driver engages the locking disk by means of a pin projecting from the locking disk into a slot in the lockplug driver. The slot extends for 90° around the lockplug driver. Therefore, the lockplug must be rotated 45° in either direction before engaging the locking disk. Likewise, when the motor rotates the locking disk, the locking disk is free to rotate 45° before engaging the lockplug driver. This is necessary because a force applied to rotate the lockplug will rotate the DC motor as well, but a force applied through the DC motor will have no way to rotate the lockplug.
The latch includes a pair of roller switches between the motor housing and lockplug housing. Each roller switch includes a cantilever with a roller end abutting the bearing surface of the locking disk. Depressing the cantilever closes an electrical circuit. When the roller abuts a cutout in the locking disk, the cantilever is extended, opening the circuit. Likewise, when the roller abuts the other portions of the disk's bearing surface, the cantilever is depressed. One cutout corresponds to the latch's locked position, and the other corresponds to the latch's open position. Therefore, the first of the two roller switches will be open when the latch is locked, and the second of the two roller switches will be open when the latch is open. The combined state of the two latches therefore indicates whether the latch is locked, unlocked, or open. This signal can be directed to a programmable logic controller (PLC), which, given the current state of the latch, and the desired state of the latch from a remote controller, will turn the motor the proper amount to bring the latch into the desired state. For example, if the latch is unlocked (both roller switches closed) and the user switches the latch to open, the PLC will rotate the motor until the second roller switch engages the corresponding cutout in the locking disk and opens. The PLC will then receive a signal that the latch is open, and stop rotating the motor.
It is a principal object of the present invention to provide a novel latch assembly which is selectively engagable with a keeper member, and includes a spring locking member which is spring-loaded with its own spring force for engaging and releasing a pawl from a keeper member when a handle is actuated.
It is another object of the present invention to provide a locking member which is comprised of spring steel or plastic.
It is another object of the present invention to provide a latch assembly with a locking component which can be operated with a key or other operator, such as radio, infrared, electronic or other means, which selectively engages the locking member against movement.
It is another object of the present invention to provide a latch assembly with a locking mechanism which can be operated with a key or other operator, such as, a solenoid controller, where the key and solenoid control the same locking element but provide independent ways to lock and unl
Lee K.
Paul & Paul
Southco Inc.
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