The present invention relates to electronic locks. More specifically, the present invention relates to an improved solenoid lock mechanism. The lock mechanism is capable of remaining locked when it is subjected to an impact force.
Electronically controlled solenoid locks are becoming an increasingly popular choice for locking portable devices such as portable safes, gun boxes, and briefcases to make opening and closing these devices more convenient through the use electronic keys, pin pads or biometric sensors.
Solenoid locks typically employ a common electromagnetic solenoid with a return spring. In the de-energized state the spring forces the core into the locked position through a latch mechanism. When the coil is energized, the magnetic force generated by the coil forces the core to compress the return spring, releasing the latch mechanism and opening the lock.
Advantages of this type of locking system are that opening and closing the lock can be achieved very quickly and the cost of this simple structure is relatively low compared with other electronic locking methods. The disadvantage of this type of system, especially when used for portable devices, is that the weight of the solenoid core can overcome the return spring force when the core is subjected to an impact load along its axis, such as that caused by dropping or banging the portable device against a hard surface. This situation could occur by accident or when a person is intentionally tampering with the portable device. When the return spring force is overcome by the kinetic energy of the core, the portable device can open unexpectedly spilling the contents or allowing a thief to take the contents.
Previous attempts have been made in the art to overcome this significant disadvantage of solenoid locks. One obvious solution would be to make the solenoid spring stronger in order to overcome the kinetic energy of the core during an impact. However, the increase in spring force required to overcome the kinetic energy of the core would require a larger electromagnetic coil and consume considerably more power, causing an increase in the size, weight, and cost of the system. Obviously, none of these is desirable for a portable consumer device.
Another solution to the problem has been to spring bias the core perpendicular to its axis. This solution also has the effect of increasing the power, weight, and size requirements. Additionally, it increases the complexity of the system by adding components.
Yet another solution involves the use of an elaborate mechanism requiring movement of multiple parts in perpendicular planes. This solution also dramatically increases the complexity, weight, size, and cost of the system.
While the above solutions may work in theory, none are practical for use in portable consumer devices. As such, a need exists for a compact, reliable, energy efficient, and low cost solenoid lock mechanism for portable devices capable of withstanding impact forces.
Objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In the primary embodiment, the present invention is generally directed to a solenoid lock mechanism comprising the following elements: an electromagnetic solenoid with a cylindrical collar on a cylindrical core and a return spring to push the core to an extended position, a substantially cylindrical bar with a cylindrical collar that is substantially the same weight as the solenoid core, a lever with a fixed central pivot, and a moveable latch mechanism. In one embodiment, the solenoid is mounted in a fixed position on the fixed part of a lock mechanism, such that when it retracts the core moves to the right. The cylindrical bar is slidably mounted such that its longitudinal axis is in a plane substantially parallel to the longitudinal axis of the solenoid core. The bar is supported at two points by a fixed guide, where the support points are located towards the end of each bar. The collar on the bar is positioned between the two fixed guide support points, which are a fixed part of the lock mechanism. This arrangement prevents the bar from sliding completely through the holes in the fixed guide in either direction. The lever is mounted on a substantially central fixed fulcrum, where the fulcrum is fixed at a substantially central location between the solenoid and the bar. The lever is constructed so that one end is long enough to make contact with the collar on the core and the other end can contact the end face of the bar closest to the solenoid. However, the lever is not connected to either the bar or the solenoid and is free to pivot about the fulcrum until it contacts either the end of the bar or the core collar. In the de-energized state, the return spring constantly pushes the core of the solenoid through a hole in the latch mechanism, which is a moveable part of the lock. When the solenoid is energized, the core retracts through the hole in the latch and compresses the return spring, thus allowing the portable device to be opened. Assuming the lever is touching the core collar, as the core retracts, the collar on the core pushes the lever around the fulcrum and slides the bar to the left. When the solenoid is again de-energized, the return spring forces the core back through the latch to lock the portable device, but there may be no movement of the either the bar or the lever during this operation as there is no force on either the lever or the bar. It is this feature that creates the impact resistance of the lock without requiring extra power, since the solenoid does not have to overcome excessive spring force or excessive friction from a complex mechanism in order to prevent the lock from opening. If a portable device containing the lock mechanism is dropped, banged or otherwise impacted in a manner that causes the core to move against the return spring toward the retracted position, the collar will contact the lever and begin rotating the lever toward the end of the bar. Since the bar has substantially the same weight as the core, the kinetic energy of the bar will be substantially the same as the core during the impact. However, since the bar will be moving in the same direction as the core, the bar will contact the lever before the core retracts through the hole in the latch, because the bar does not have to overcome the resisting force of the return spring. The force exerted on the lever by the bar pushes the lever back against the collar on the core with a force sufficient to keep the core engaged with the hole in the latch, preventing accidental opening. Thus this solenoid lock mechanism solves the problem of impact resistance with a simple mechanical system that is energy, weight and cost efficient.
Additional objects and advantages of the present subject matter are set forth in, or will be apparent to, those of ordinary skill in the art from the detailed description herein. Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of the present subject matter may include various combinations or configurations of presently disclosed features, steps, or elements, or their equivalents (including combinations of features, parts, or steps or configurations thereof not expressly shown in the figures or stated in the detailed description of such figures). Additional embodiments of the present subject matter, not necessarily expressed in the summarized section, may include and incorporate various combinations of aspects of features, components, or steps referenced in the summarized objects above, and/or other features, components, or steps as otherwise discussed in this application. Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the remainder of the specification.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which includes and makes reference to the appended figures, in which:
Repeat use of reference characters throughout the present specification and appended drawings is intended to represent the same or analogous features or elements of the invention.
The present application generally provides for an impact resistant solenoid lock. In order to fully understand the advantages of the present disclosure,
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While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining and understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations, and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art.