Cylinder bolt mechanism in a repeating rifle

Abstract

 The invention relates to a cylinder bolt mechanism in a repeating firearm with receiver and bolt, comprising a bolt body (5) with a mainspring (56) and a firing pin (11), a rotatable bolt head (9), a handle (13), and locking means (4) in the receiver interacting with the bolt head. The handle is designed as a lever mechanism, rotatable in a plane about a hinge (25), the centre axis of which is perpendicular to said plane, said plane being parallel to a plane coinciding with the centre axis of the firing pin. Transmission means (14) are arranged to transform the turning movement of the handle about said hinge into a turning movement of the bolt head (9) in relation to the bolt body and a pushing back of the firing pin, the pulling back of the handle thereby causing a compression of the mainspring.

Description

TECHNICAL SCOPE

[0001] The invention relates to a cylinder bolt mechanism in a repeating rifle with receiver and bolt, comprising a bolt body with a mainspring and a firing pin, a rotatable bolt head, a handle, and locking means for the bolt situated in the receiver and interacting with the bolt head. More specifically the invention relates to a cylinder bolt mechanism of the type where the handle movement is straight, of the so called "straight pull action" type.

PRIOR ART

[0002] With most repeating action firearm systems with cylinder bolt mechanisms the repeating movement involves rotation. Such rotation is detrimental to fire rate and accuracy, as is well known. Therefore, many attempts have been made to construct firearm systems based on a straight bolt handle movement, so called "straight pull action". For example, an early but technically imperfect construction is described in Swedish patent No 748, published in 1886, while a technically more advanced construction is described in my international patent application, W083/02153, made public. These known "straight pull action" constructions have in common that the mainspring is compressed at the final stage of the forward loading movement of the bolt action. In some cases this is experienced as a drawback, since this working mode of the mechanism requires that the bolt is moved forward at a considerable speed. This obstructs silent loading, which is desirable in certain forms of hunting. Conventional modern hunting weapons are partly for this reason designed so that the mainspring is compressed when the gun is opened, which so far has not been possible to offect in an acceptable way with straight bolt action mechanisms.

DISCLOSURE OF THE INVENTION

[0003] The object of the invention is to provide a firearm system of the kind described in the introductory statement above in which the mainspring is compressed when the gun is opened. Another object is to provide a firearm system of a very uncomplicated construction which is in this respect also an improvement of my earlier firearm system, described in the aforementioned international patent application.

[0004] These and other objects may be realized by making the handle in the form of a lever mechanism, pivoting in a plane about a hinge, the rotational axis of which is perpendicular to a plane which coincides with the centre axis of the firing pin, and by providing means of transmission to transform the pivoting movement of the handle about said hinge into a rotational movement of the bolt head about the centre axis of the firing pin.

[0005] Another object of the invention is to prevent unauthorized use of the gun by blocking its mechanism with a lock and key. This object may be realized by the interaction of said means of transmission and the firing pin nut with a cylinder lock arranged in the latter.

[0006] Further objects and characteristics of the invention will become apparent from the appended claims and the following description of a preferred embodiment of the cylinder bolt mechanism.

BRIEF DESCRIPTION OF DRAWINGS

[0007] In the following description of preferred embodiments, reference will be made to the attached drawings, in which

Fig. 1 is a perspective view of a first embodiment of a bolt mechanism and the receiver as viewed from the rear raight side;

Fig. 2 is a plan view of the same mechanism;

Fig. 3 is an exploded view of the main parts of the bolt;

Fig. 4 is an elevation, partly sectional, of the firing pin with the mainspring, the mainspring tube, and the firing pin nut;

Fig. 5 is a sectional view corresponding to V-V of Fig. 4, the surrounding bolt body having been added to the drawing;

Fig. 6 is an elevation of a cylinder lock;

_Fig. 7 is a view of the same cylinder lock, corresponding to VII-VII of Fig. 4;

Fig. 8 is an elevation showing the bolt body from the right;

Fig. 9 shows the bolt body from the rear;.

Fig. 10 is a perspective view on a larger scale of the means for turning the bolt head and compressing the mainspring;

Fig. 11 shows the rear part of the mainspring tube, the front end of the firing pin nut, and a pair of guiding curves of said parts;

Fig. 12 shows the back side of a rack bar;

Fig. 13 is a view of the same rack, the view corresponding to XIII-XIII of Fig. 12;

Fig. 14 shows the bolt with the bolt head locked, the gun having been fired but the spring not yet compressed;

Fig. 15 shows the same parts after the mainspring has been compressed and the bolt head turned to neutral position;

Fig. 16 is a perspective view of a locking ring of a construction previously known per se, being a part of the system;

Fig. 17 is an exploded view of a firing pin nut fitted with a cylinder lock according to a second embodiment;

Fig. 18 is a view corresponding to XVIII-XVIII of Fig. 17, a rear view of a lock case with a safety cam;

_Fig. 19 is a view corresponding to XIX-XIX of Fig. 17, a rear view of the cylinder lock, a pin, and a locking ball on a larger scale;

_Fig. 20 is a transverse sectional view of the second embodiment of the bolt body in the area of the locking ball; and

Fig. 21 is a perspective view of part of the transmission of the second embodiment.

[0008] The bolt 1 consists of the following main parts, see Fig. 3: A bolt body 5 with a mechanism housing 6, covered by a lid 7, a bolt neck 8, rotatable in the bolt body 5, with a bolt head 9, a mainspring tube 10 with a firing pin 11 movable therein, a firing pin nut 12, a hadle 13, a gear transmission arrangement 14 and a cylinder lock 15.

[0009] The bolt body 5 consists of a cylinder, the mechanism housing 6 being an integral part of this cylinder, constituting a projection thereon. More specifically, the mechanism housing 6, being generally a parallelepiped, extends at an angle upwards to the right in relation to a vertical plane through the centre line of the barrel. The inclination of the mechanism housing 6 to the vertical plane is about 55°, when the gun is directed normally. The bolt body 5 is provided with a central bore for the bolt neck 8, the mainspring tube 10 and the firing pin nut 12. At the front end the bolt body 5 is provided with three claws 16, corresponding to three claw slots 17 between three studs 18, directed radially inwards in the locking ring 4 and forming a claw coupling which locks the ring 4 in the position determined by the bolt body 5 in a way known per se. The design of these parts is described in my aforesaid international patent application WO/8302153.

[0010] In the mechanism housing 6 there is a transverse guide 20 for a rack bar 21. The guide 20 is in the form of a groove in the housing, open at both long sides of the housing 6. The guiding groove 20 is bounded at the front side by a wall 22 and at the back by the housing body 23.

[0011] In the housing body there is a recess 24 fitted with a swivel pin 25 for the handle 13. The handle 13 is designed as a two-arm lever. The longer lever arm 26 extends from the bolt body 5 and has a grip 27. The shorter lever arm has been designated 28 and extends forward approximately at a right angle to the longer lever arm 26, in the form of a tooth 28 which fits in a slot 29 in the top side of the rack bar 21. A bearing arrangement between the two lever arms of the handle interacts with the swivel pin 25 and has been designated 30. Thus, the handle 13 swivels in a plane perpendicular to the swivel pin 5, the centre axis of which is in turn perpendicular to a plane coinciding with the centre line of the barrel and consequently with the firing pin axis. In other words, the swiveling plane of the handle 13 is parallel to said plane through the centre line, said plane being inclined at an angle of 35° to the vertical plane as the guns i held in a normal position aiming forward. The handle 13 can be turned through an angle of about 35° from a front position, in which the handle is directed directly outwards from the mechanism housing 6, and a rear position, in which the handle 13 is directed at an angle rearwards. The front position is bounded by a separating wall 31 between the recess 24 and a longitudinal groove 32 in the housing body 23 along the left side thereof. The rearward movement of the handle is limited by the front edge 33 of a right side wall 34 of the housing body 23. The two end positions are additionally determined by a stud 35 between the opening 36 in the side wall 34 accomodating the handle 13 and the guide 20. In the front wall 22 there is a front dovetail slot 37 and in the housing body 23 there is a rear dovetail slot 38 to accomodate dovetails 37' and 38', respectively, on the bottom side of the lid 7.

[0012] The longitudinal groove 32 along the housing body 23 forms a guide for a rotation stop 40. This is in the form of a bar equipped with an extension 41 directed sideways and guided in the groove 32, extending out through an opening in the left side wall 43 of the housing body 23. To the rear of rotation stop 40 there is a spiral spring 44 (rotation stop spring) arranged to press the rotation stop 40 forward. When barring rotation, the front tip 45 of the rotation stop 40 extends past the rear edge of the rack bar guide 20 into a cut 66 in the rack bar 21, thus when in this position preventing the rack bar 21 from moving from a right position to a left position. The extension 41 in this position is flush against the front edge of the opening 42, see Fig. 15. When the extension 41 has been pressed back in the opening 42 by a means devised to-this end but not yet described, to the extent that the front tip 45 of the rotation stop has passed the rear edge of the rack bar guide 20 when moving backwards, the rack bar 21 may be moved to the left in the guide 20. Left in this connection signifies at an angle upwards leftwards and right signifies at an angle downwards rightwards, with respect to Fig. 1. The rack bar 21, the handle 13, the rotation stop 40 and the rotation stop spring 44 are locked in their respective places by the led 7.

[0013] On the bottom side of the bolt body 5 there is a guide slot 47, see Fig. 8, to accomodate the sear and at the rear end of the bolt body 5 there is a first recess 48, coinciding with the guide slot 47, and a second recess 49 at the left side of the bolt body 5.

[0014] The firing pin 11 extends through the mainspring tube 10 and is screwed to the firing pin nut 12 at its rear end. The nut is provided with a central bore 50 to accomodate the cylinder lock 15, see Figs. 5, 6, 7, and 9. A key hole has been designated 51, a lock plunger 52, and a key 67. The lock plunger 52 may be turned in a slot 53 in the firing pin nut 12 and a slot 54 in the inside of the bolt body 5 from a position wherein the lock plunger 52 is situated in the slot 49 in front of a specially arranged tooth 55 at the rear end of the firing pin nut, see Fig. 10, to a locked position at a right angle to the said first position, in other words approximately opposite the first recess 48 and the tooth 55 on the firing pin nut 12, said tooth being situated in said first recess. In this first, unlocked position, the firing pin assembly (firing pin, firing pin nut, and mainspring tube) may be moved into and out of the bolt body as the lock plunger 52 moves in or out, respectively, through the recess 49. In the locked position, however, the firing pin assembly is locked in the bolt body 5 by the lock plunger 52 being confined in the slot 54 on the inside of the bolt body 5. In this context it should also be noted, that the slot 54 on the inside of the bolt body 5 is situated in that part of the bolt body 5 which is near the lock plunger 52 when the lock plunger 52 is in its forward position relative to the bolt body, in other words when the mainspring 56 is not compressed. When the mainspring 56 has been compressed, the firing pin nut 12 has been moved rearwards relative to the mainspring tube 10 in a manner to be described later. In this position, the gun cannot be locked, since the lock plunger 52 when in this position no longer coincides with the slot 54 on the inside of the bolt body 5.

[0015] The front end of the mainspring tube 10 is threaded, so that the firing pin assembly depicted in Fig. 4 may be screwed to the bolt neck 8. To accomplish this, the former is entered into the bolt body 5 from the front end, while the firing pin assembly is entered into the bolt body 5 from the rear, and the two parts are then screwed together inside the bolt body. The rear part 58 of the mainspring tube 10 has the same external diameter as the firing pin nut 12. One of its two halves is designed as a sector of a pinion 59. This sector is exposed and extends up through an opening 60 in the bolt body 5 in the area of the rack bar guide 20, in such a way that the pinion sector can interact with the teeth 61 on the bottom side of the rack bar 21, see Figs. 10 and 12. The rear part 58 of the mainspring tube 10 is provided with a compression cam 62 corresponding to and interacting with a compression cam 63 on the firing pin nut 12, so that as the mainspring tube 10 is made to rotate about its axis by means of the transmission 14 (the firing pin nut 12 is barred from turning by the sear catch 64 and the tooth 55 entering their respective slots 48 and 49), the two compression cams will slide against one another whereby the firing pin nut 12 will be pressed rearwards, the mainspring 56 simultaneously being compressed in the mainspring tube 10.

[0016] Said rotation of the mainspring tube 10 is accomplished by means of the handle 13, as the handle is moved rearwards from its front position towards its rear position, pivoting about the swivel pin 25. By the leverage applied by the handle the tooth 28 in the slot 29 in the rack bar 21 is moved "rightwards". Thus, the rack bar 21 is moved to the right as the handle is pulled back about the pivot/swivel pin 25, the rack bar 21 by interacting with the pinion sector 59 of the mainspring tube 10 turning the tube clockwise. As the mainspring tube 10 turns, the mainspring 56 is compressed as the two compression cams 62, 63 are pushed and slide against one another as was described above, and as the mainspring tube 10 turns, the bolt neck 8 also turns and hence the bolt head 9 as well. When the turning has been completed, i e when the handle 13 has been brought to its rearmost position, the firing pin tube 10 and hence the bolt head 9 have been turned approximately 60° as a result of the gear ratio of the transmission 14, bringing the studs 18 on the bolt head 9 in coincidence with the claws 16 on the bolt body, the bolt head thereby becoming free to move into and out of the locking ring 4. The starting position before the mainspring is compressed and before the bolt head has been turned to its free position is illustrated in Fig. 14, while Fig. 15 shows the handle in its rearmost position, the mainspring being compressed (note that the firing pin nut has been moved rearwards from the mechanism housing 6) and the bolt head 9 being turned to its free position. In this position the bolt 1 may be moved rearwards in the receiver 2 to allow a new cartridge to be entered into the cartridge chamber. During this procedure, the handle 13 remains in its rearmost position, see Fig. 15. The bolt head is introduced into the locking chamber in the rear part of the barrel (see my international patent application W083/02153), the claws 16 on the bolt body entering the claw slots 17 in the locking ring 4. During this entire procedure, the handle 13 is prevented from swiveling forwards by the front tip 45 of the rotation stop 40 extending into the rack bar guide 20 and locking the rack bar 21. Only at the very end of the procedure, the rotation stop 40 is moved aside as the extension 41 hits a stop 65 at the left side of the receiver 2, see Fig. 2, thereby being moved rearwards in the opening 42. Finally, the rotation stop leaves the rack bar guide 20. The handle 13 may now be moved forward, turning about the swivel pin 25, and via the rack transmission 14 move the rack bar 31 leftwards, turning the mainspring tube 10, the bolt neck 8, and the bolt head 9, the bolt head being moved into locking position in front of the locking ring 4. In this position, the mainspring is already compressed, since it was compressed when the gun was opened.

[0017] It is natural that the design of the mechanism can be modified within the spirit and scope of the invention. Below some modifications will be described with reference to Figs. 17-21. The amendments, which are believed to be improvements over the first embodiment described above, relate both to the lock-and-key mechanism, making it entirely proof against attempts to pick the lock or to break it open, and to the transmission means transforming the turning movement of the handle into the turning of the bolt head relative to the bolt body.

[0018] The firing pin nut fitted with a cylinder lock shown in Fig. 17 comprises a lock sleeve 120 with a compression cam or safety tooth 63', a dog sleeve 121 with a locking ball 52', resting in a hole 129 of smaller diameter than the ball 52', a cylinder lock 15', a steel ring 150 and a socket 125 with a sear catch 64'. The lock sleeve 120 has a threaded bore 122 to accomodate the firing pin. In the wall of the lock sleeve there is a hole 123 for the locking ball 52', the hole diameter being slightly larger than that of the ball. The rear part of the lock sleeve 120 is designed as four claws 124 to be fitted over the cylinder lock 15', the outside of which is provided with four splines 151. In Fig. 19 one of these spline keys is obscured by the locking ball 52'. The cylinder lock 15' per se is in accordance with pior art and comprises in a known way a finger 152 to be entered into the dog sleeve 121 there to engage said sleeve by means of a pin 153, see Fig. 19. The cylinder lock 15' in accordance with prior art has a key slot 51' coinciding with a slot in the steel ring 150. In the front part of the socket 125 a notch 126 has been cut to acommodate the compression cam 63' and the side of the socket has a hole 127 for the locking ball 52'. When the device is assembled, the two holes 123 and 127 of the same size are coaxial. At the rear end of the socket there is an axial hole 128 to acommodate the steel ring 150. At assembly, the steel ring 150 is placed from the inside in the hole 128, the cylinder lock 15' and the dog sleeve 121 are put into the socket 125, and the lock sleeve 120 is entered between the inside of the socket 125 and the cylinder lock 15', so that the spline keys 151 fit between the claws 124. The assembly is locked by a locking pin, not shown, through the front parts of the socket and lock sleeve walls. The bolt body 5', see Fig. 20, has a recess 48' there is a recess 49 to acommodate the locking ball 52'.

[0019] The device described with reference to Figs. 16-21 functions as follows. To lock the gun, a key is entered in the key slot 51'. When the key is turned to lock the gun, the locking ball 52' is lifted out of the hole 129 in the dog sleeve 121, as the finger 152 and hence the tubular dog sleeve 121 is turned 90° about the centre axis. The locking ball 52' is pressed radially outwards through the holes 123 and 127 in the lock sleeve and the socket 125, respectively, to enter the recess 49' in the bolt body 5', see Fig. 20. This locks the integrated firing pin nut 12' to the bolt body 5', barring these parts from moving relative to one another. It is impossible to drill the lock open from the key hole end, since the cylinder lock is made of hardened steel. Should an attempt be made to force the lock for example by sticking a screwdriver tip into the key hole and trying to turn it, this will only, if any turning takes place, result in the permanent fixation of the locking ball in its position. The only way to open the gun if this has happened is to make a hole radially directly outside the ball 52', such as by spark machining, but this would require both advanced equipment and special spark machining expertise, as well as a precise knowledge of the position of the locking ball 52'.

[0020] Referring now to the improved transmission means, this improvement comprises a modification of the rack bar, designated by reference numeral 21', and the shorter lever arm, designated 28'. The lever arm 28' is designed in the form of a sector of a pinion, and the rack bar 21' has been provided with teeth on that part also which faces the lever arm 28'. The bottom side of the rack bar 21' is still provided with teeth 61 interacting with the teeth 59 on the mainspring tube 10, see Fig. 10 of my previous patent application.

Claims

1. Cylinder bolt mechanism in a repeating firearm with receiver and bolt, comprising a bolt body (5) with a mainspring (56) and a firing pin (11), a rotatable bolt head (9), a handle (13), and locking means (4) in the receiver interacting with the bolt head,characte- rized in that the handle is designed as a lever mechanism, rotatable in a plane about a hinge (25), the centre axis of which is perpendicular to said plane, said plane being parallel to a plane coinciding with the centre axis of the firing pin, that transmission means (14) are arranged to transform the turning movement of the handle about said hinge into a turning movement of the bolt head (9) about the centre axis of the firing pin.

2. Cylinder bolt mechanism according to claim 1, characte- rized in that the bolt head is attached to a mainspring tube (10), rotatable inside the bolt body and interacting with said transmission means.

3. Cylinder bolt mechanism according to claim 2, characte- rized in that compression means (62, 63) are arranged to push the firing pin nut rearwards thereby compressing the mainspring as the bolt body is turned about said centre axis by pulling the handle rearwards about the hinge from a front position, in which the locking means in the receiver locks the bolt head, to a rear position, in which the locking means does not lock the bolt head and the bolt is free to be moved rearwards in the receiver.

4. Cylinder bolt mechanism according to claim 2, characte- rized in that said compression means comprise compression cams (62, 63) situated between the mainspring tube and the firing pin nut.

5. Cylinder bolt mechanism according to claim 2, characte- rized in that a rotation stop (40) is arranged to lock the handle in its rear position no later than at the point when the bolt, the mainspring being compressed, is moved rearward out of engagement with said locking means in the receiver as the firearm is opened, and that said rotation stop is arranged to be moved aside no earlier than at the point where the bolt head is returned to a position in which it is flush against the surface of a stop on the barrel behind the cartridge chamber, the handle thereafter being free to be moved forwards from its rear to its front position by being turned about the hinge, thereby causing the bolt head to turn and to be locked in its front position.

6. Cylinder bolt mechanism according to claim 1, characte- rized in that said transmission means comprise a gear mechanism (59, 61).

7. Cylinder bolt mechanism according to claim 5, characte- rized in that said gear mechanism comprises a rack (21), arranged to be moved sideways by means of a shorter lever arm (28) of the handle (13), hinged to the bolt body (5), and a pinion (59) on the mainspring tube, interacting with said rack.

8. Cylinder bolt mechanism according to any of the preceding claims, characterized in that said transmission means, hinge, and rotation stop are arranged in a mechanism housing (6) in the rear part of the bolt body, said housing extending upwards and sideways from the elsewise cylindrical bolt body while the handle extends at an angle downwards from the mechanism housing.

9. Cylinder bolt mechanism according to any of the preceding claims, characterized in that the handle pivots in a plane which is perpendicular to the centre axis of the hinge.

10. Cylinder bolt mechanism according to any of the preceding claims, characterized in that a cylinder lock is arranged in the firing pin nut comprising locking means interacting with the bolt body in order to obstruct, when in locking position, any axial movement of the firing pin relative to the bolt body, thereby also preventing the mainspring from being compressed and the bolt from being brought out of its front, locked position by a rearward movement of the handle from its front to its rear position.

11. Cylinder bolt mechanism according to any of the claims 1-10, characterized in that the rack bar is provided with teeth on two sides forming an angel, said teeth being arranged to interact with teeth on the mainspring tube and with teeth on a lever arm (28') of the handle.

Drawing