GB2261695A

GB2261695A - Key ejecting lock security device

Info

Publication number: GB2261695A
Application number: GB9124336A
Authority: GB
Inventors: Peter King
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-11-15
Filing date: 1991-11-15
Publication date: 1993-05-26
Also published as: GB9124336D0

Abstract

A device for preventing a key from being left in a lock 1, comprising a rod 2, extending along the keyway 3 of the lock, which is biased by a spring 4 towards the keyhole. When a key is inserted into the keyway it pushes the rod away from the keyhole, against the bias. If the key is not turned to a different position, in which the key may be left, the biasing force pushes the rod back along the keyway towards the keyhole, thus ejecting the key from the lock, when the force inserting the key is removed. <IMAGE>

Description

LOCK SECURITY DEVICE The present invention relates to a lock security device.

In order for a lock to be an effective security measure it is imperative that the key is removed after locking the lock; however, a surprising number of people forget to remove the key from the lock after locking, thus leaving it for anyone to come along and open the lock using the key left there. This is a problem in all areas where locks are used, such as doors in buildings, safes, etc. However, one area where this is becoming a major problem is in cars and other motor vehicles.

Recent reports show that 20% of car thefts arise due to people leaving the key in the ignition lock while they leave the vehicle unattended.

People also tend to leave car keys in the ignition lock when the car is in the garage or the drive. This provides the additional danger of young children, playing in the car, being able to start the engine. Previous lock and key systems have been devised wherein an audible alarm is activated if the key is left in the lock.

However, loud alarms are often considered a nuisance and are prone to faulty activation.

Thus, there is a need for a simple mechanism for preventing a key from being left in a lock.

According to the present invention there is provided a lock comprising a main body and a keyway having a keyhole at one end and having a rod axially movably biasing means such that the rod is normally held by said biasing means to extend along said keyway towards said keyhole; wherein, when a key is inserted into said keyway, the key may push the rod against the force of the biasing means along the keyway, away from the keyhole such that said rod, under the return force of said biasing means, opposes insertion of the key and thereby causes the key to be ejected from the lock when no force is applied to the key in the insertion direction.

The lock is preferably a cylinder lock having several different positions to which the key may be turned whereby the key is inserted in a first position and, unless the key is then turned to a second position, it will be ejected when the inserting force is removed.

Preferably the biasing means comprises a tension spring between the distal end of the rod and the main body of the lock. Alternatively, the biasing means may comprise a compression spring between the distal end of the rod and a stop or housing.

A preferred embodiment of the invention, in relation to a motor vehicle ignition lock, will now be described by way of example only and with reference to the accompanying drawings, wherein: Fig. 1 shows a cross-section taken along the length of a lock according to a first embodiment of the present invention, in the 'key-out' position; Fig. 2 shows the lock of Fig. 1 in the 'key-in' position; and Fig. 3 shows a lock according to a second embodiment, in the 'key in' position.

Referring to Figs. 1 and 2, in a first embodiment a vehicle ignition lock consists of a main cylinder 1 disposed within a barrel (not shown). The cylinder 1 has a coaxial inner keyway 3, extending along the length of the main cylinder 1. A keyhole 8 is provided at one end of the cylinder 1 across the width of the keyway 3 for insertion of a key 7 into the keyway 3. At the other end of the cylinder 1 there is provided a central aperture of a diameter less than the keyway 3, surrounded by a rod guide 6. A rigid, preferably metal, rod 2 passes through the aperture into the keyway 3 and is kept straight by the rod guide 6. At one end, the rod 2 extends along the keyway 3 towards the keyhole 8 in alignment therewith.

The other end of the rod 2 passes through the aperture and the rod guide 6. The rod 2 is of such a diameter that it can move axially relative to the guide 6 but radial movement is prevented by the guide 6 so that the rod 2 is kept in alignment with the keyhole 8. The end of the rod 2 distal from the keyhole 8 is connected to one end of a tension spring 4 by means of a connection 5.

The other end of the spring 4 is attached to the main cylinder 1. When there is no key inserted in the lock, as shown in Fig. 1, the spring 4 is relaxed and the rod 2 extends along the keyway 3 towards the keyhole 8.

An exemplary car ignition lock has four key positions: an OFF position; an AUX position wherein power is supplied to operate devices such as a radio, a fan or a heater; an IGNITION position and a START position to start up the engine. Initially, the key 7 is inserted into the keyhole 8 in the OFF position. If the user wishes to switch on the power to activate, e.g. the radio, the key 7 is then turned to the AUX position and can be left in that position. In order to start the car, the key 7 is turned further, to the IGNITION position and can also be left in that position. The START position is usually spring biased back to the IGNITION position.

However, if the key is inserted in the OFF position and is not turned to one of the other positions or if the key has been turned back to the OFF position, the key ejection mechanism will operate to eject the key 7 from the lock.

When the key 7 is inserted into the keyway 3 via the keyhole 8 it abuts against the free end of the rod 2. As the key 7 is pushed further into the keyway 3 it pushes the rod 2 along the keyway 3 away from the keyhole 8.

Since the other end of the rod 2 is attached to one end of the spring 4, which is fixed at its other end to the main cylinder 1 of the lock, this movement causes the spring 4 to be stretched. If the key 7 is then turned to the AUX or IGNITION position a stop within the lock mechanism (not shown) retains the key in the lock and the spring is held in the stretched position shown in Fig. 2.

However, if the key 7 is left in the OFF position and the user stops applying a force to push the key 7 in, the return force of the spring 4 as it returns to its relaxed state causes the rod 2 to move back along the keyway 3 towards the keyhole 8, thus pushing the key 7 out of the keyway 3 and ejecting it from the lock. Thus, the key 7 cannot be left in the lock in the OFF position.

In a second embodiment, a compression spring 9 is positioned between the rod 2 and a stop or housing 10.

This embodiment operates similarly to that as described above; however, the natural state of the spring 4, when no key is inserted, is expanded. When the key 7 is inserted, it pushes the rod 2 which causes the spring 4 to compress, as shown in Fig. 3. The return force of the spring 4 causes it to expand, thus pushing the rod back along the keyway 3 and ejecting the key 7.

Alternatively, the movement of the rod could be driven by a solenoid which is activated or deactivated by insertion of the key, however, the preferred arrangement uses the rod and spring which is simpler and less expensive.

Claims

1. A lock comprising a main body and a keyway having a keyhole at one end and having a rod axially movably located in said keyway, said rod being biased by a biasing means such that the rod is normally held by said biasing means to extend along said keyway towards said keyhole; wherein, when a key is inserted into said keyway, the key may push the rod against the force of the biasing means along the keyway, away from the keyhole such that said rod, under the return force of said biasing means, opposes insertion of the key and thereby causes the key to be ejected from the lock when no force is applied to the key in the insertion direction.

2. A lock as claimed in claim 1 wherein said biasing means comprises a tension spring.

3. A lock as claimed in claim 1 wherein said biasing means comprises a compression spring.

4. A lock as claimed in any preceding claim wherein the end of said rod distal from said keyhole is attached to one end of said spring means and the other end of said spring means is attached to the main body of said lock.

5. A lock as claimed in claim 1 wherein said biasing means comprises a solenoid.

6. A lock as claimed in any preceding claim further comprising guide means for guiding movement of said rod.

7. A lock as claimed in any preceding claim wherein said main body of said lock is cylindrical and said keyway is provided coaxial thereto, along its length.

8. A lock as claimed in any preceding claim wherein said lock has several key positions from one of which said key may be ejected.

9. A lock as claimed in any preceding claim wherein said lock is for use as a motor vehicle ignition lock.

10. A lock substantially as hereinbefore described with reference to the accompanying drawings.