The present invention relates to an electronic lock having two modes of operation.

Some types of locks can be configured to operate in different modes. For instance, in the case of electronic door strikes, these types of locks may be configured to operate in a Power to Open (PTO) mode or a Power to Lock (PTL) mode. Electronic door strikes are used to control access through doors in buildings. In the PTO mode, the lock is biased to a locked state and becomes unlocked when power is applied to the lock. In the PTL mode, the lock is biased to an unlocked state and becomes locked when power is applied to the lock.

US-A-2006/0226663 discloses a magnetic lock in which its mode of operation can be changed between a PTL mode and a PTO mode.

US-A-2004/0061343 discloses an electrically-operated door strike in which its mode of operation can be changed between a fail-safe mode and a fail-secure mode.

The present invention provides an electronic lock having two modes of operation, the electronic lock including: a lock body; a solenoid plunger mounted with the lock body; a spring for biasing the solenoid plunger in a direction with respect to the lock body; and a mode selector mountable within the lock body and oriented in accordance with a desired mode of operation, the mode selector being biased in the same direction as the solenoid plunger by the spring when no power is applied to the solenoid plunger, the mode selector moving into a void within the lock body to lock the electronic lock, the mode selector being operable for switching the mode of operation of the electronic lock, the mode of operation being determined by its orientation with respect to the electronic lock, the mode selector including: first and second bodies of different sizes; the first and second bodies being spaced apart by a resilient member.

The resilient member may include a helical spring.

The first and second bodies may be cylindrical.

The first and second bodies may be right cylindrical.

The resilient member may be mounted coaxially with either of the first or second bodies.

The first and second bodies may be of different lengths.

The resilient member may be mounted to either of the first or second bodies by being inserted into an aperture formed in either of the first or second bodies.

The first and second bodies may be formed from brass.

In a power to open mode, the second body is adjacent the solenoid plunger and at least a portion of the first body is located within the void to lock the electronic lock.

In a power to lock mode, the first body is adjacent the solenoid plunger and at least a portion of the first body moving into the void to lock the electronic lock.

The electronic lock may be an electronic door strike.

An embodiment of the present invention will now be described, by way of example only, to the accompanying drawings, in which:

• Figure 1 illustrates is an end view of a mode selector for an electronic lock according to an embodiment of the invention;
• Figure 2 is a cross section view along the line A-A of figure 1;
• Figure 3 is a cut-away view of an electric door strike including the mode selector of figure 1 in the Power to Open mode with no power applied;
• Figure 4 is a cut away and exploded view of the lock of figure 3;
• Figure 5 is a cross sectional view along the line B-B of figure 3;
• Figure 6 shows the lock of figure 3 in the Power to Open mode with power applied;
• Figure 7 shows the lock of figure 3 in the Power to Lock mode with no power applied; and
• Figure 8 shows the lock of figure 3 in the Power to Lock mode with power applied.

Referring to figure 1, a mode selector 3 is shown in end view. One end of a first body is shown in the form of brass cylinder 2.

Referring to figure 2, the mode selector 3 is shown in side cross sectional view. A second body in the form of brass cylinder 2' is shown which is of a different size to cylinder 2 by way of being of a different length.

The cylinders 2, 2' are spaced apart by a resilient member in the form of metal helical spring 1. Spring 1 is mounted coaxially of the cylinders 2, 2' and is inserted into apertures formed in either of the first and second cylinders. A small amount of adhesive is used to affix each end of spring 1 into the apertures.

Spring 1 is resilient. If the spring is elastically deformed, then it will return to its original shape as shown in figure 2.

Referring to figure 3, an electronic lock of the type known as an electric door strike is shown including a lock body 11 and a face plate 8. Mode selector 3 is shown lying in a cylindrical aperture in lock body and is biased against solenoid plunger 7 by way of spring 4 which operates as the solenoid return spring. Keeper 6 is pivotally mounted in the lock in a conventional manner

In use, the lock is mounted in a door frame and controls access through the door. The latch of the door is retained in a recess behind the keeper 6. If the keeper is free to move, then the latch is free to be released from the aperture behind the keeper and the lock is said to be unlocked. In this state, the door may be pushed open and the keeper pivots to release the latch. If the keeper is not free to move then the lock is said to be locked. When the lock is locked, the door may only be opened by withdrawing the latch by use of a key or interior door handle.

Referring to figure 4, mode selector 3 may be removed from the lock by unscrewing end cap 5. The lock is switched between PTO and PTL modes by removing the mode selector, changing its orientation, and re-inserting mode selector 3 back into the lock and refitting end cap 5.

Referring also now to figures 6 to 8, the operation of the various modes of the lock will now be explained.

In figures 3 and 6, the lock is shown in the Power to Open (PTO) mode. It is important to note the orientation of the mode selector 3. The longer cylinder 2 is shown to the left, and the shorter cylinder 2' is to the right. That is to say, the mode selector has been inserted into the lock with the shorter cylinder 2' being inserted first as shown in figure 4.

In figure 3, no power is being supplied to solenoid 7. Spring 4 biases the mode selector and solenoid to the right. It can be seen that a portion of the longer cylinder 2 extends into void 9 provided in lock body. This obstructs movement of keeper 6 and thus the lock is locked.

The obstruction of the keeper 6 by cylinder 2 is illustrated in Figure 5. It can be seen that the diameter of the cylinders 2, 2' is greater than the width of curved slot 10. Thus, the keeper is obstructed. However, the diameter of spring 1 is less than the width of slot 10. Thus, if neither of cylinders 2 or 2' extend into void 9, then the keeper is unobstructed. As the keeper moves, spring 1 is loosely received in slot 10.

Referring to figure 6, power is now being supplied to solenoid 7 and it has moved the mode selector to the left against the force of spring 4. Note that spring 4 has been compressed. It can be seen that no part of either of cylinders 2 or 2' extend into void 9. Thus, the keeper is not obstructed from moving pivotally and the lock is open.

In figures 7 and 8, the lock is shown in the Power to Lock (PTL) mode. The orientation of the mode selector has been changed when compared with figures 3 and 6. The longer cylinder 2 is shown to the right, and the shorter cylinder 2' is to the left. That is to say, the mode selector has been inserted into the lock with the longer cylinder 2 being inserted first.

In figure 7, no power is supplied to solenoid. Spring 4 biases the mode selector and solenoid to the left. It can be seen that no part of either of cylinders 2 or 2' extend into void 9. Thus, the keeper is not obstructed from moving pivotally and the lock is open.

Referring to figure 8, power is now being supplied to solenoid 7 and it has moved the mode selector 3 to the left against the force of spring 4. Note that spring 4 has been compressed. It can be seen that a portion of cylinder 2 extends into void 9 provided in lock body. This obstructs movement of keeper 6 and thus the lock is locked.

Whenever the lock is in the locked state, it is due to cylinder 2 of mode selector 3 extending across the boundary between the lock body 1 and the void 9. When cylinder 2 extends into the void 9 the lock is said to be locked. Sometimes in use, the cylinder 2 may experience a high load such as if an attempt is made to force open the lock by a person striking a blow to the door or lock. This may cause some small local deformation of spring 1. However, spring 1 is resilient and returns to its original shape thus ensuring correct alignment of the two cylinders 2 and 2'.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the scope of the present invention as defined by the appended claims.