The present invention relates to a safety lock preventing the introduction of a live round to the firing chamber of firearms which eject by automatic, semi-automatic or manual means the spent cartridge case from the chamber of the weapon through an ejection port. A further application of the lock is to block alignment of the cylinder of so-called revolvers with the barrel, preventing firing.

The purpose of the lock is to render the firearm safe when not in its intended use, but to allow its rapid return to such use by quick removal of the lock from the firearm, which can remain with its magazine or cylinder in its loaded state.

An objective of the invention is to disable the firearm to prevent its accidental or unauthorised discharge by persons not in custody of the key separable from the body of the lock inserted in the firearm; yet to render its' enablement rapid and simple by use of the key to permit removal of the lock from the firearm.

Another objective of the invention is to enable the custodian of the firearm and the lock to have the lock available at all times by carrying it on a key-ring or similar implement to which the key remains attached until separated from the firearm when the lock is installed in the firearm and to which the body of the lock becomes reattached on removal from the firearm.

A further objective of the invention is to enable custodians of more than one weapon, regardless of calibre or model, to require only one key for all locks emplaced in those firearms

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by virtue of the common-keying of the locking mechanism, thus preventing confusion among different keys in cases of emergency and inconvenience arising from the loss of the key to a particular lock.

According to the present invention the lock has a body comprising two mirror halves joined together at assembly; a lock bolt Ca cylindrical, conical, pointed shaft) contained in an outer cylinder (which is an integral part of the body ⁾ of slightly greater diameter permitting the bolt to move back and forth within it, the assembly resembling a firearm cartridge; an activating slide (a cylindrical shaft) that gives motion to the lock bolt through a pivoted lever and is also part of the locking unit; the pivoted lever that connects the slide and lock bolt and transmits motion from one to the other; a lock cylinder assembly that allows or prevents movement of the slide through the body . from side to side, depending on the position of the cylinder, having as components the activating slide, a locking dog (a moveable double lug section activated by a spring and a key), and the spring (which keeps an upward force on the locking dog); the key, retained in the cylinder when unlocked and removable when the cylinder is locked; and a dedent plate offering slight resistance to movement of the lever in the unlocked position.

An embodiment of the invention is now described by example only with reference to the accompanying drawings.

Figure 1 is a side view of a lock in accordance with the invention with the activating slide 3 and the locking bolt 2 in solid outline in the unlocked position and in broken outline in the locked position ; and the key inserted in the body.

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Figure 2 is a key-end view of a lock with the key removed.

Figure 3 is a sectional side view of the components of a lock and their positions in the unlocked condition.

Figure 4 is a sectional side view of the components of a lock and their positions in the locked condition.

Figure 5 is a sectional side view, at ninety (90) degrees to the view in Figure 4, of the positions of components of a lock cylinder in locked condition.

Figure 6 is a sectional side view, at ninety (90) degrees to the view in Figure 3, of the positions of components of a lock cylinder in unlocked condition.

Figure 7 shows the position of a lock in the ejection port of a firearm with the lock bolt extended into the barrel from the rear, in the locked condition with key removed.

For firearms with ejection ports, the lock is inserted into the open port; the lock bolt 2 is extended into the rear of the barrel by rearward movement of the activating slide 3 which causes the pivoted lever 4 to rotate inside the body 1 of the device and to propel the lock bolt 2 in the forward direction; the lock bolt 2 is locked in the extended position by turning the attached key 6 through ninety degrees, immobilising the activating slide 3 and preventing operation of the lever 4 and retraction of the lock bolt. The key 6 is now detachable and is removed, leaving the device locked in the firing chamber and not removable until the lever 4 is released by inserting the key in the body 1 of the lock, and turning it through ninety (90) degrees. This allows forward movement of the activating slide 3 within the cylindrical

channel in the body 1 to retract the lock bolt 2 from the barrel and permit removal of the lock from the ejection port allowing the loading mechanism to be activated and a live round to enter the chamber, so returning the firearm immediately to firing position.

In the application to revolvers the cylinder is swung open and the lock is inserted into the space in the frame vacated by the cylinder, the lock bolt is aligned with the rear of the barrel and extended into it using the activating slide and locked in place by turning the key. Return of the revolver to firing condition is done by retracting the lock bolt from the barrel by reinserting and turning the key through ninety (90) degrees to allow operation of the activating slide and by removal of the lock from the frame to allow the cylinder to be swung closed.

In the particular embodiment shown, the body 1 comprises mirror image halves contoured externally to contain the components of the lock and shaped internally to accommodate them and to allow their movement in accord with the lock's operation. At the key 6 end the body is of a cross section to contain the lock cylinder 5 and its components the activating slide 3 the locking dog 7 and the spring S. Between the key 6 and the lock bolt 2 ends of the lock the body 1 narrows to contain the lever 4 and widens again to a cylinder whose length and diameter fit the ejection ports and calibres of the firearms for which the lock is designed and within which cylinder the lock bolt 2 is extended and retracted by operating the activation slide 3.

The diameter of the lock bolt assembly (the cylinder part of the body 1 and the lock bolt 2) of a particular model of the lock is engineered for the smallest calibre of the range of

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The activating slide 3 has a slot 3a in Figure 4 into which the shorter arm of the lever 4 fits and within which it rotates as the activating slide is moved from side to side. The travel of the activating slide 3 and the lock bolt 2 in either direction is controlled by the arms of the lever 4 contacting the angled faces 2a in Figure 4 of the interior of the body 1. Extending the slot 3a on the key 6 side of the activating slide 3 is a flat cutout with length and curvature matching the outer diameter of the interior end of the lock cylinder 5 which the locking faces 5a of the lock cylinder legs 9a Figure 6 abut in the locked condition Figure 4 preventing travel of the activating slide and retraction of the lock bolt.

The lever 4 that connects the activating slide 3 and the lock bolt 2 Figure 3 and transmits motion from one to the other is a flat bar thick enough to provide lateral strength with a central circular segment from which the two arms of unequal length extend at 180 degrees from each other. The central segment rests in a circular cutout interior to the body 1 in which it pivots and within which it is contained by the joined halves of the body 1. When the activating slide 3 transmits motion the lever passes over a raised projection of the dedent plate 10 in Figure 3 which resists loose movement of the lever 4 in the unlocked condition.

The lock cylinder 5 has a flat surface at the outer, key 6 end and a channel groove la in Figure 3 at its interior end through which the activating slide 3 moves in the unlocked condition Figure 3. In the locked condition Figure 4 the key 6 has turned the channel groove la at 90 degrees to the axis of the activating slide 3 which is at its rearmost point of travel. The key has been removed. The locking faces 5a of the legs 9a in Figure 6 bordering the channel groove la of the

lock cylinder 5 abut the ends of the cutout in the activating slide and stop its movement. At the external lateral edge of the key end of the lock cylinder is a 90 degree radial channel that engages a stop Figure 5 in the key end of the body 1 and limits the turn of the lock cylinder assembly 5 to 90 degrees by action of the key 6.

The locking dog 7 in Figure 5 is a oveable double lug section actuated by the coil spring 8 and the key 6, which fits into and slides within a longitudinal cutout section of the lock cylinder opposite the stop channel. The external lug 7a is located to fit and travel within the radial groove 6a in the body 1. The inner lug 10a maintains the correct alignment of the locking dog 7 in the lock cylinder 5 during its operation.

Figure 5 shows the lock cylinder 5 in the locked condition in the body 1. The locking dog 7 is under spring 8 pressure and is forced to the key end (top) of the lock cylinder 5 causing t _h e external lug 7a on the locking dog 7 to move out of alignment with the radial groove 6a in the body 1. The external lug 7a has moved out of the radial groove 6a into the slot 8a intercepting the radial groove 6a at 90 degrees to its axis and is positioned to place the legs 9a in Figure 6 of the lock cylinder 5 at right angles to and within the cutout in the activating slide 3 thus preventing its movement.

In Figure 6 the key 6 has been inserted in the lock and turned through 90 degrees, placing the lock cylinder 5 in the unlocked condition. The key 6 has a step of predetermined size which has contacted the inner lug 10a of the locking dog 7 and forced it down (away from the key end ⁾ compressing the coil spring until the face 11a of the key met the body 1. This put the external lug 7a of the lock cylinder 5 in line with the radial groove 6a of the body 1 and allowed the lock

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cylinder 5 to rotate by 90 degrees bringing the legs 9a of the lock cylinder 5 parallel to the axis of the activating slide 3 and allowing it to move from side to side again.

The embodiment described above is by way of example only and is illustrated by reference to a range of firearms with calibres from 9mm to .45 inch calibres, but it must be realised that the invention is universally applicable to firearms of lesser and greater calibres including handguns, rifles and shotguns that eject spent cartridge cases by automatic, semi-automatic or manual means or that have revolving cylinders by which cartridges are aligned with the barrel and fired through it.

The lock can be made from hardened material including metals and plastics using effective methods of shaping those materials.

Modifications are possible within the scope of the invention.

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