Bolt head locking arrangement for firearm weapons

Abstract

A bolt head locking arrangement for a recoil operated weapon where projectile is expelled by discharging a cartridge. The weapon comprising an action body, a barrel, and a bolt assembly, the bolt assembly being slidable within the action body. The bolt assembly comprising a bolt head, a locking slide and a firing pin, and a locking means arranged so that, upon loading a new cartridge for discharging, the locking means positively lock the bolt head such that, for a predetermined amount of time after the loaded cartridge is discharged, the locked bolt head stops the cartridge from retreating into the action body. The locking means is substantially in an in-line configuration with the bolt assembly. The locking means are arranged so that the recoil momentum of the weapon, caused by the discharge, is used for unlocking the bolt head, wherein the locking means are arranged so that, upon discharge of the cartridge, the locking slide recoils backwards and, once the bolt head is unlocked, the inertia of the locking slide facilitates the recoil of the bolt head.

1 . A bolt head locking arrangement for a recoil operated weapon where projectile is expelled by discharging a cartridge, the weapon comprising a longitudinal action body, a longitudinal barrel, the barrel being a part of or axially attached to the action body, and a bolt assembly, the bolt assembly being slidable within the action body so as to affect at least one of; loading cartridges in the barrel for discharging, discharging cartridges and extracting discharged cartridges; the bolt assembly comprising a bolt head, a locking slide and a firing pin, at least some of which being arranged for moving with respect to each other, wherein the arrangement further comprises locking means arranged so that, upon loading a new cartridge for discharging, the locking means positively lock the bolt head such that for a predetermined amount of time after the loaded cartridge is discharged, the locked bolt head stops the cartridge from retreating into the action body, thus eliminating the penetration of pressure caused by the discharge into the action body, the locking means is substantially in an in-line configuration with the bolt assembly, and said locking means are arranged so that the recoil momentum of the weapon, caused by the discharge, is used for unlocking the bolt head, and the locking means are arranged so that, upon discharge of the cartridge, the locking slide recoils backwards and, once the bolt head is unlocked, the inertia of the locking slide facilitates the recoil of the bolt head, wherein the locking slide comprises a timing surface of predetermined length and the locking means comprise at least one locking lug that is engageable with the timing surface so as to move between open and closed configuration, wherein in the closed configuration the at least one lug is located within the cross-sectional area of the bolt head to allow the sliding movement of the head within the action body, while in open configuration the at least one lug extends beyond this cross-sectional area to abut with an abutment surface of the action body and prevent rearward movement of the bolt head, wherein in use; when the bolt assembly is moved forward to load a cartridge, the locking slide moves with respect to the bolt head so that the timing surface engages the at least one lug to push it into an open configuration, so that when the bolt head is moved fully forwardly, the bolt head is locked in a sealing engagement with the sealing inner surface of the barrel and in an abutment engagement with the abutment surface of the action body; and upon discharging the cartridge, the locking slide moves backwards, causing the entire predetermined length of the timing surface to withdraw from its engagement with the at least one lug and allow the at least one lug to move into closed configuration, thus unlocking the bolt head and allowing it to recoil. 
   
   
       2 . The arrangement of  claim 1 , wherein the locking means are arranged so that, after the bolt head is unlocked, a residual of the gas pressure formed during the discharge is used for assisting with the recoil of the bolt head. 
   
   
       3 . The arrangement of  claim 1 , wherein the locking means are arranged so that, upon loading a cartridge, a first abutment surface is brought into an abutment engagement with the locking means to bring them into an abutment engagement with a second abutment surface, thus locking the bolt head, the locking means being further arranged so that a predetermined time after the discharge of the cartridge, the first abutment surface is withdrawn from a locking engagement with the locking means, thus releasing them from the locking abutment engagement with the second abutment surface and allowing the bolt head to recoil. 
   
   
       4 . The arrangement of  claim 1 , wherein at least one of the following parameters can be changed to adjust the time delay, during which the bolt head is locked, so as to allow the weapon to discharge a cartridge having different charge characteristics or projectile mass;
 the length of the timing surface;   the mass of the locking slide, the bolt head, the bolt assembly or the mass of the entire weapon;   the mechanical characteristics of a recoil spring used to move the bolt assembly forwards after a recoil.   
   
   
       5 . The arrangement of  claim 4 , wherein the following parameters can be changed to adjust the time delay, during which the bolt head is locked, so as to allow the weapon to discharge a cartridge having different charge characteristics or projectile mass, in the following manner;
 increasing the length of the timing surface to allow for larger charge to be used; decreasing the mass of the locking slide, the bolt head, the bolt assembly or the mass of the entire weapon to allow for larger charge to be used;   to reduce the spring constant of the recoil spring to allow for larger charge to be used.   
   
   
       6 . The arrangement of  claim 1 , wherein the firing pin is arranged to be able to discharge a cartridge only if the bolt head is substantially in a locked configuration. 
   
   
       7 . The arrangement of  claim 6 , wherein the firing pin is arranged to protrude through an opening in the bolt head so that, when the bolt head is not in a locked configuration, the firing pin is unable to reach the cartridge and effect a discharge. 
   
   
       8 - 15 . (canceled) 
   
   
       16 . A locking arrangement for a bolt head of a recoil operated firearm having a barrel; wherein in locked configuration, the locking arrangement is adapted to retain the bolt head of the firearm in abutting engagement with the barrel for a predetermined time delay subsequent to discharge of the firearm; the locking arrangement comprising at least one lug pivotally attached to the bolt head; the at least one lug being operable between a first retracted unlocked position and a second extended locking position; the locking arrangement further comprising a locking slide provided with a timing surface such that when the firearm is in a loaded and cocked condition the timing surface retains the at least one lug in the second locking position; the locking arrangement being such that the length of the timing surface determines the delay between the discharge and unlocking of the at least one lug, as the locking slide is subjected to recoil induced movement relative the bolt head, wherein the locked configuration of the locking arrangement is adapted to retain a cartridge in the cartridge chamber of the firearm; the predetermined time delay being sufficient for pressure to drop in the barrel of the firearm, thereby to minimize the ingress of gasses and other foreign material into the firing mechanism of said firearm. 
   
   
       17 . The locking arrangement of  claim 16 , wherein the bolt head of the firearm is adapted for sliding movement in a cylindrical action body housing the firing mechanism; the action body coaxial being with the barrel of the firearm. 
   
   
       18 . The locking arrangement of  claim 16 , wherein the at least one pivotally attached lug of the bolt head is biased into the retracted unlocked position when disengaged from said timing surface. 
   
   
       19 . The locking arrangement of  claim 16 , wherein the action body is provided with an annular recess; a wall of the recess adapted to engage with the at least one lug when the at least one lug is in the second extended locking position. 
   
   
       20 . The locking arrangement of  claim 19 , wherein the locking slide is adapted for sliding movement in the cylindrical action body; the locking slide being biased into a forward position within the action body by a recoil spring; forward sliding movement of the locking slide firstly driving the bolt head to the abutting engagement with the barrel, and secondly engaging with the at least one lug to pivotally rotate the lug into the second extended locking position with the wall of the annular recess. 
   
   
       21 . The locking arrangement of  claim 16 , wherein, subsequent to a discharge, a rearward sliding movement of the locking slide is communicated to the bolt head, once the at least one lug has disengaged from the timing surface, such that the bolt head is retracted rearwards from its abutting engagement with the barrel. 
   
   
       22 . The locking arrangement of  claim 16 , wherein a firing pin of the firearm operates along apertures in the bolt head and the locking slide; the length of the firing pin arranged so that engagement of the locking pin with a primer of a cartridge is prevented unless the locking slide is in the forward position with the bolt head locked in the abutting engagement with the barrel. 
   
   
       23 . A bolt head locking arrangement of  claim 1 , wherein the unlocking and/or the recoil of the bolt head is affected by utilising gas pressure generated in the barrel of the firearm at discharge, either by a gas tube providing blow-back of the slide, or a connecting rod operated by a gas actuated piston. 
   
   
       24 . A bolt head locking arrangement of  claim 1 , wherein the barrel is slidingly mounted, so that the unlocking and/or the recoil of the bolt head is facilitated by the recoil of the barrel. 
   
   
       25 . A bolt head locking arrangement of  claim 1 , wherein the firearm is a single shot or a pump action manually operated firearm and wherein the unlocking and/or the recoil of the bolt head is affected manually. 
   
   
       26 . The arrangement of  claim 2 , wherein the firing pin is arranged to be able to discharge a cartridge only if the bolt head is substantially in a locked configuration. 
   
   
       27 . The arrangement of  claim 3 , wherein the firing pin is arranged to be able to discharge a cartridge only if the bolt head is substantially in a locked configuration. 
   
   
       28 . The arrangement of  claim 4 , wherein the firing pin is arranged to be able to discharge a cartridge only if the bolt head is substantially in a locked configuration. 
   
   
       29 . The arrangement of  claim 5 , wherein the firing pin is arranged to be able to discharge a cartridge only if the bolt head is substantially in a locked configuration.