US3494216A

US3494216A - Bolt action for repeating rifle

Info

Publication number: US3494216A
Application number: US728715A
Authority: US
Inventors: Jerry D Haskins
Original assignee: Champlin Haskins Inc
Current assignee: Champlin Haskins Inc
Priority date: 1968-05-13
Filing date: 1968-05-13
Publication date: 1970-02-10
Anticipated expiration: 1987-02-10

Description

Feb. 10, 1970 J. D. HASKINS 3,494,215

BOLT ACTION FOR REPEATING RIFLE Filed May 15, 1968 3 Sheets-Sheet 1 INVENTOR.

:E E (/EPEY D. HAsk/k/s 1970 J. D. HASKINS 3,494,216

BOLT ACTION \FORREPEATI'NG RIFL-E.

Filed May 13. 1968 3 Sheets-Sheet 2 INVENTOI}. U5??? 0. HA SK/A/S Feb. 10, 1970 J. D. HASKINS BOLT ACTION FOR REPEATING RIFLE 3 Sheets-Sheet 3 Filed May 13, 1968 INVENTQR. deem 0., HA SKI/d5 U.S. CI. 4216 12 Claims ABSTRACT OF THE DISCLOSURE A rifle bolt action including an elongated, hollow bolt carrying circumferentially spaced, axially extending medial ribs which extend along a medial portion of the bolt. Positioned at a forward end of the bolt in axial alignment with circumferentially spaced medial ribs and spaced axially therefrom are circumferentially spaced forward ribs. In the case of both the forward and medial ribs, these ribs are separated by slots, with the slots between the forward ribs aligned with the slots between the medial ribs. At the rear of the bolt, an annular build-up portion defines a J-slot aligned with a slot in one of the medial ribs and extending toward the forward end of the bolt. Each medial and forward rib is beveled at one rear corner of the rib to facilitate rotation into alignment with cooperating locking lugs provided in a receiver. The receiver includes aligned forward and rear receiver rings each containing locking lugs, and a bore extends through the entire receiver for slidingly accommodating the bolt. Each receiver ring contains a circumferentially spaced, internally located locking lug which are dimensioned and spaced from each other to permit sliding movement therebetween of the forward and medial ribs on the bolt during retraction and seating of the bolt, and to engage the forward and medial ribs when the bolt is rotated about its axis after being moved to the firing position. The receiver further includes a backstrap which is connected to the stock of the rifle.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to firearms, and .more particularly, to bolt action repeating rifles.

Brief description of the prior art In bolt action rifles as now produced, the breech bolt provided is usually an elongated, hollow, cylindrical member which carries a plurality of locking lugs on the bolt which cooperate with locking lugs in a receiver or bolt housing in which the bolt slides during operation of the rifle. The cooperation between the lugs carried on the bolt and those positioned within the receiver is such that looseness develops within a relatively short period of operation and use of the gun, changes in the head space develop after repeated firings of the rifle, and extraction of cartridge cases becomes impaired with extended usage. Conversely, in some instances, binding of the bolt in the receiver will develop due to misalignment of the locking lugs so that, in general, the withdrawal or shoving home of the bolt cannot be carried out with the smooth, fast movement required for rapid pointing and eflective and accurate shooting. Further than this, if the lugs carried by the receiver do not effectively lock the bolt in precisely the same position following each cocking and seating movement of the bolt, the bolt face is then disposed at a slightly different angle with respect to the barrel and the pattern and accuracy of fire over repeated firings is affected.

3,494,216 Patented Feb. 10, 1970 BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention is an improved bolt action for a rifle. Broadly described, the bolt action of the invention comprises an elongated hollow bolt having a forward or face end and a rear end. The bolt is slidable and, to a limited extent, rotatable within a receiver as is characteristic of conventional bolt action rifle construction. An important feature of the assembly is the exterior construction of the bolt. A plurality of elongated, circumferentially spaced ribs extend axially along a medial portion of the outside of the bolt and terminate at points spaced inwardly from the opposite ends of the bolt. At the face end of the bolt, a plurality of relatively short, circumferentially spaced, forward ribs are secured to the bolt in axial alignment with the medial ribs and are spaced axially from the medial ribs. At the rear end of the bolt, a built-up annular portion extends around the bolt and is spaced axially from the medial ribs.

The receiver of the bolt action is an elongated structure adapted to be connected to the barrel and stock of the rifle, and having a forward ring, a rear ring and an elongated case ejection port between the rings. Positioned inside the forward ring are a plurality of circumferentially spaced, radially inwardly extending locking lugs. These lugs are spaced to permit the forward ribs on the bolt to pass therebetween during the characteristic reciprocating, sliding .movement of the bolt during operation of the rifle. A group of circumferentially spaced locking lugs are also located within the rear receiver ring and are also spaced to pass the medial ribs of the bolt during operation of the rifle. The arrangement of the ribs on the bolt and lugs on the receiver is such that when the bolt is rotated about is longitudinal axis about /6 revolution after being seated for firing, the locking lugs in the forward ring of the receiver are positioned immediately behind and in abutting contact with the forward ribs on the bolt, and the locking lugs in the rear ring of the receiver are immediately behind and in abutting contact with the medial ribs on the bolt. During retraction and seating of the bolt, the bolt is guided and maintained in a course aligned with the barrel axis by the cooperation between its elongated medial ribs and the locking lugs in the rear ring of the receiver.

In one embodiment of the invention, the bolt is provided with a recessed face and a double extractor mechanism which includes a pair of extractor latches located on opposite sides of the face recess. An ejector pin is mounted in the forward end of the bolt for spring biased extension into the recess between the extractor latches, and one of the extractor latches is adjustable in its cartridge gripping tenacity so that the distance to which empty cases are ejected from the rifle after firing can be adjusted as desired. Moreover, the provision of the opposed extractor latches permits the cartridge case to be withdrawn and ejected without contacting the receiver, and thus prevents wear and grooving of the receiver over extended periods of usage of the rifle.

From the foregoing description of the invention, it will be apparent that an important object of the invention is to provide an improved bolt action for a rifle which greatly enhances the safety with which the rifle may be fired.

An additional object of the invention is to provide an improved rifle bolt which, due to its construction, reciprocates more smoothly and evenly in its receiver.

A further object of the invention is to provide improved extractor and ejector mechanisms in a bolt action for a rifle.

Additional objects and advantages of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a side elevation view of a bolt action rifle which includes the improved bolt action of the present invention.

FIGURE 2 is a plan view of the rifle depicted in FIG- URE 1.

FIGURE 3 is a side view, partly in section and partly in elevation, of the central portion of the rifle, showing details of the action of the rifle.

FIGURE 4 is a side elevation view of a receiver forming a portion of the action of the invention.

FIGURE 5 is a top plan view of the receiver depicted in FIGURE 4.

FIGURE 6 is a bottom view of the receiver depicted in FIGURE 4.

FIGURE 7 is an end elevation view of the receiver as it appears when viewed from the rear end thereof.

FIGURE 8 is an end elevation view of the receiver as it appears when viewed from the forward end thereof.

FIGURE 9 is a section taken along line 9-9 of FIG- URE 4.

FIGURE 10 is a section taken along line 1010 of FIGURE 4.

FIGURE 11 is a section taken along line 11-11 of FIGURE 4.

FIGURE 12 is a side elevation view of the bolt assembly of the invention.

FIGURE 13 is an end elevation view of the bolt assembly illustrated in FIGURE 12 showing the bolt assembly as it appears when viewed from the forward end.

FIGURE 14 is a longitudinal sectional view through the bolt assembly illustrated in FIGURE 12 with the firing pin, extractor and ejector mechanisms illustrated in elevation.

FIGURE 15 is a sectional view taken along line 1515 of FIGURE 12.

FIGURE 16 is a side elevation view of the bolt assembly similar to the view of FIGURE 12, but with the assembly rotated about its axis about from the position it occupies in FIGURE 12.

FIGURE 17 is a sectional view taken along line 1717 of FIGURE 18.

FIGURE 18 is an end elevation view of the forward end face of a modified breech bolt which can be utilized in the assembly of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring initially to FIGURE 1 of the drawings shown therein is a bolt action rifle constructed in accordance with the present invention and including the improved bolt action of the invention. The rifle includes a stock 12, a barrel 14, and a receiver 16 which threadedly engages the barrel 14. The rifle 10 also includes a bolt assembly 18, a portion of which can be seen in FIGURE 1, a magazine box 20, a trigger guard 22, and a trigger 24.

The more immediate environment of the improved bolt action constituting the present invention is depicted in FIGURE 2 of the drawings. It will be noted in referring to FIGURE 2 that the receiver 16 is threadedly secured at its forward end to the barrel 14, and is provided at its opposite end with an elongated backstrap 26 which is fitted to the contour of the stock 12 and functions to transmit recoil forces from the breech bolt and receiver to the stock. Securement of the backstrap 26 to the stock is by means of a bolt 28 which is passed through the escutcheon of a trigger plate 30 and a bolt 32 which is passed through the stock 12 beneath a trapdoor cap 34 positioned on the pistol grip 36 of the stock. Another stock securing bolt 38 is extended through the forepiece 40 from the escutcheon of a plate 42 to the internally threaded recoil lug 43 secured to the forward portion of the receiver.

The receiver 16 in which the bolt assembly 18 is mounted is an elongated member including a forward receiver ring 44, a rear receiver ring 45 and a medial or central portion 46. The medial portion 46 is cut away over a substantial distance to provide a case ejection port 47 through which the empty cartridge cases may be ejected by the bolt mounted ejection mechanism as hereinafter explained. On its lower side and opposite the ejection port 47, the bolt has an elongated generally rectangular opening 48 is formed therein into which is fitted the upper portion of the magazine box 21 when the rifle is assembled.

Positioned in the forward portion of the rear receiver ring 45 and extending radially inwardly from the internal walls thereof are a plurality of circumferentially spaced rear locking lugs 50a, 50b, and 500, these being best illustrated in FIGURES 7, 9 and 11 of the drawings. The rear locking lugs are spaced about 120 from each other around the bore through the rear receiver ring 45 and it will be noted that the locking lugs are spaced rearwardly from the forward end of the rear receiver ring 45 and forwardly from the rear end thereof. Rearwardly from the rear locking lugs 50a, 50b, and 500, the side wall of the rear receiver ring 45 is cut away to provide a generally L-shaped guide channel 52 in which the bolt handle, hereinafter described, may be rotated when the bolt is rotated within the receiver to and from a locked or firing position. The guide channel 52 includes a cam surface 54 for guiding the bolt handle in its movement.

Immediately beneath the guide channel 52 and centered on the lower side of the receiver is an apertured stud 55 through which a suitable screw or other attachment member can be passed for the purpose of securing a trigger mechanism, designated generally by reference numeral 56, to the lower side of the receiver. This screw, together with the support afforded by the trigger plate 30, retains the trigger mechanism 56 in its proper position with respect to the receiver 16 and the bolt assembly 18 when the rifle is assembled.

Disposed within the forward receiver ring 44 and to the rear of the internally threaded portion of this ring which engages the barrel 14 are a plurality of circumferentially spaced, radially inwardly extending forward locking

lugs

58a, 58b, and 580. These lugs are best illustrated in FIGURES 8 and 10 of the drawings. It will be noted in referring to FIGURE 5 that the forward locking lugs 58a, 58b, and 58c of the receiver 16 are spaced rearwardly from the internal threads of the receiver which engage the barrel 14 and are separated from these threads by an intervening counterbore 60 which is of slightly smaller diameter than the threaded bore at the forward end of the receiver, but of larger diameter than the internal diameter of the inner surfaces of the

lugs

58a, 58b, and 580. The counter-bore 60 accommodates the forward ribs on the breech bolt when the breech bolt is seated in its firing position as will be hereinafter explained.

Positioned to the rear of the rear receiver ring 45 and positioned between this ring and the backstrap 26, the receiver includes a grooved extension plate 64. The grooved extension plate 64 is centrally grooved with a bolt channel 66 which is cut on the same radius as the bore formed through the entire length of the receiver 16 for accommodating the breech bolt as hereinafter explained. The bolt channel 66 is best illustrated in FIGURE 4, and has formed in the deepest portion thereof an elongated sear slot 68 and a threaded aperture 70 into which the stock securing bolt 28 hereinbefore described is extended. It will further be noted that the sear slot 68 lies within an elongated groove 72 formed at the bottom or base of the bolt channel 66, with this groove being provided for the accommodation and guidance of a lug carried by a cocking piece forming a part of the bolt assembly 18 as hereinafter described. Spaced forward of the groove 72 and within the rear portion of the rear receiver ring 45 is a stop pin aperture 74 which extends through the bottom portion of the receiver and accommodates a stop pin 76. The stop pin '76 is extended through the upper portion of the trigger mechanism 56 and into a guide slot provided in the bolt assembly 18 as hereinafter described. The stop pin 76 is spring biased to a position in which it projects above the bore provided through the rear receiver ring 45, and suitable and conventional mechanism is provided in conjunction with the trigger mechanism to permit this stop pin to be easily manually retracted from the bore through the receiver so as to permit the bolt assembly 18 to be completely removed from the receiver 16 when desired.

The trigger mechanism utilized in conjunction with the improved bolt action of the invention is conventional and known in the art, and will not be described in great detail. The mechanism, of course, includes the usual trigger 24, the trigger guard 22, a sear 78, and a sear mounting bracket 80 which pivotally supports the sear by means of a sear pivot pin 82. A safety pin 84 is provided for preventing depression of the sear by a sear spring (not shown) when the trigger 24 is pulled and the gun is set on safety. The function and interrelationship of the trigger 24 and sear 82 will be well understood by those skilled in the art, and no effort is here made to illustrate or explain the details of construction of the sear spring, the trigger spring, or the intervening linkage between the trigger and sear. It is sufficient for an undzrstanding of the improved bolt action of the present invention to indicate that the sear 78 functions to engage a shoulder provided on a lug projecting from the lower side of a cocking piece forming a part of the bolt assembly 18 at such time as the rifle is cocked for firing, and to release or become disengaged from this shoulder when the rifle is fired, all as hereinafter further explained.

Positioned forward of the trigger mechanism 56 and secured beneath the central or medial portion 46 of the receiver 16 is the magazine box 20. The magazine box is of conventional construction, having an open top which communicates with the magazine box slot or opening 48 in the lower side of the receiver 16. Contained within the magazine box 20 is a cartridge follower 90 which is biased upwardly by a follower spring 92 to feed shells or cartridges through the magazine box slot 48 in the receiver 16 in a conventional manner. The follower spring 92 rests upon or is supported by a floor plate 94 which is pivotally secured in the plate 42 by means of a pivot pin 96. The floor plate 94 can be released to permit unused cartridges to be retrieved from the magazine box by pushing upon the extension 100 of a floor plate release lever 102 which is retained in its plate closing position by means of a spring 104.

The bolt assembly 18 of the present invention is best illustrated in FIGURES 12-16. As here illustrated, the bolt assembly 18 includes the breech bolt proper 106 which comprises an elongated cylindrical member having a forward or face end 106a and a rear end 10Gb. Adjacent the forward or face end of the elongated, cylindrical breech bolt 106, the bolt is provided with a plurality of circumferentially spaced, radially outwardly extending locking ribs. In the illustrated embodiment of the invention, three of these locking ribs are provided and are spaced at 120 intervals around the breech bolt 106. The three ribs are designated by

reference numerals

1080, 108b, and 1080 and are separated by intervening grooves 1100, 11%, and 1100. The rear corner of each of the

forward locking ribs

108a, 108b, and 1080 (in the direction of seating rotation of the bolt when it is in use) is beveled or tapered so that a contacting edge of the forward locking lugs 58a-580 provided inside the forward receiver ring 44 will bear against this tapered surface and cam the receiver bolt forward as it is rotated to the seated or firing position as hereinbefore described.

The forward locking rib 108a is provided with an axially extending slot 112 in which is located a spring metal finger (see FIGURE 14) extending from an extractor latch 114 which can be seen in the end view of the bolt assembly depicted in FIGURE 13. The extractor latch 114 has a tapered arcuate surface at the forward edge thereof and extends int-o a recess 116 formed in the face of the breech bolt 106. At the center of the recess 116 in the face of the breech bolt 106, a firing pin aperture 118 is provided. Diametrically opposed to the extractor latch 114 on the opposite side of the recess 116 is an opening in the face of the bolt which communicates with an elongated, axially extending bore 122 as best illustrated in FIGURE 14. An ejector pin 124 is positioned in the ejector pin bore 122 and is slidingly retained in this bore by a retention pin 126 which is extended through the forward locking ribs 10812 and 1080 and the body of the bolt 106 to pass through an elongated slot 128 provided in the ejector pin 124. The ejector in 124 is biased to a forward position by an ejector pin spring 129 located in the rear portion of the bore 122 and bearing against the rear end of the ejector pin. It will be noted in referring to FIGURE 14 that the recess 116 at the face of the breech bolt 106 is completely surrounded by an annular, forwardly extending flange 130. Thus, the rim of the case of a cartridge is completely surrounded by the flange 130 and seats flatly against the forward face of the bolt within the recess 116 when the cartridge is in the firing position.

Spaced axially along the bolt 106 from the

forward locking ribs

108a, 108b, and 1080 by a distance which is substantially equivalent to the axial dimension of the forward locking lugs 58a, 58b, and 580 within the forward receiver ring 44 are a plurality of elongated, circumferentially spaced medial locking ribs 132a, 1321), and 1320.

The medial locking ribs 132a, 13212, and 1320 are three in number in the illustrated embodiment, and are spaced circumferentially from each other around the bolt 106 on equal spacings of about 120. It will be noted that the medial locking ribs 13201, 13212, and 1320 are axially aligned with the

forward locking ribs

1080, 10812, and 1080 and are separated by axially extending

grooves

134a, 134b, and 1340 which are aligned with the

grooves

1100, 110b, and 1100 between the forward locking ribs. In a preferred embodiment of the invention, the medial locking ribs 132a132c have a length which exceeds half the length of the cylindrical breech bolt 106, and which is substantially equivalent to the distance separating the front locking lugs 5811-580 and the rear locking lugs 50a- 500.

A gas port 136 extends through the bolt 106 to the hollow interior thereof to permit gas to be vented from the interior of the bolt through the case ejection port 47 in the receiver 16 during operation of the rifle. An elongated stop pin slot 138 extends from a point spaced rearwardly from the forward end of the medial locking rib 1320 to the rear end of this rib, and receives the stop pin 76 of the trigger mechanism for a purpose hereinafter described. It will be noted in referring to FIGURES 12 and 16 that the locking ribs 132a, 13212, and 1320 are also beveled at one of the rear corners thereof to provide a tapered or camming surface which cooperates with the rear locking lugs 50a500 in the rear receiver ring 45 when the bolt is rotated to seat it in the firing position. It will also be noted in referring to these figures of the drawing that the medial rib 1320 is grooved or cut away with a small arcuately cross-sectioned groove 140 which extends from its rear end to a point well forward of the center of the rib. This groove prevents hanging of the rim of the cartridge case during reciprocation of the bolt assembly 18 in the receiver 16, and permits smooth pickup and seating of the cartridge as the bolt is rammed home preparatory to firing of the rifle.

Spaced rearwardly and axially from the

medial locking grooves

134a, 134b, and 1340 is a bolt extension and camming cylinder designated generally by reference numeral 142. In the preferred embodiment of the invention illustrated in the drawings, the bolt extension and camming cylinder 142 includes an annular camming cylinder band 143 which is formed integrally with the cylindrical breech bolt 106 and, in fact, the medial locking ribs 132a132c and the forward locking ribs 10811-1080 are also preferably formed integrally with the cylindrical bolt 106 by an appropriate machining operation. The bolt camming cylinder band 143 has secured thereto, an outwardly extending bolt handle 144 of conventional design. Cut inwardly into the camming cylinder band 143- from the forward face thereof is an L-slot 146 which is axially aligned with the stop pin slot 138 in the medial rib 132a. The annular camming cylinder band 143 has cut into the rear face thereof adjacent the end 1061) of the bolt 106, a pair of camming surfaces 148- and 150. The function of these camming surfaces will become more apparent as the description of the invention progresses.

The hollow interior of the breech bolt 106 is formed to include a bore 152 of relatively large diameter in a medial portion of the bolt, a threaded counterbore 154 spaced inwardly a short distance from the rear end 1061: of the bolt, a firing pin channel 156 in the forward portion of the bolt, and a firing pin port 158 which places the firing pin channel in communication with the recess 116 in the face of the bolt.

Slidably positioned within the hollow interior of the cylindrical bolt 106 is an elongated firing pin mechanism designated generally by reference numeral 160. The firing pin mechanism 160 includes a main firing pin shaft 162, a reduced diameter portion 164 and a firing pin tip 166. A beveled portion 168 interconnects the firing pin tip 166 with the reduced diameter portion 164. An annular collar 172 is secured around the reduced diameter portion 164, and abuts an annular spring perch 174 which may be formed integrally with or secured in any suitable manner to a turned down portion 176 located between the main firing pin shaft 162 and the reduced diameter portion 164.

An elongated compression spring 178 extends around the main firing pin shaft 162, and bears at one of its ends against the annular spring perch 174. At its other end, the firing pin compression spring 178 bears against the inner end of an elongated internally bored, externally threaded sleeve 180 which forms a portion of a cocking piece housing designated generally by reference numeral 182. The cocking piece housing 182 contains a relatively large cavity 184 disposed within a body portion 186 thereof, and the cavity 184 communicates with an elongated axially extending firing pin bore 188 which extends through the sleeve 180 and accommodates the main firing pin shaft 162.

The rear end of the main firing pin shaft 162 is threadedly engaged with a cocking piece 190 which is dimensioned to fit within the cavity 184 so that the cocking piece cannot be turned within the cavity, The cocking piece 190 carries a lug 192 which extends through an opening 194 to the cavity 184 provided in the body portion 186 of the cocking piece housing 182. The lug 192 has formed thereon a forwardly facing shoulder 193. The cocking piece 190 also has formed thereon a cocking cam 196 which rides on the end face of the annular camming cylinder band 143, and is able to contact and ride upon the camming surfaces 148 and 150 formed in this end face.

The cocking piece housing 182 is secured to the breech bolt 106 by threading the elongated, externally threaded sleeve 180 into the threaded counterbore 154 on the interior of the bolt. When the sleeve 180 is threaded a sufficient distance into the threaded counterbore 154, the face of the annular camming cylinder band 143 seats in an annular groove formed between the sleeve 180 and an axially extending external flange 198 formed around the forward end of the cocking piece housing 182. It will be noted that the underside of the cocking piece housing 182 is cut away to provide a flat surface 200 (see FIG- URE 13) in which the opening 194 to the cavity 184 is located, and that the lug 192, of the cocking piece 190 extends through this opening and projects below the planar surface 200 formed at the cutaway portion of the cocking piece housing. The lug 192 of the cocking piece 190 can thus project into, and be guided by, the elongated groove 72 formed in the grooved extension plate 64 of the receiver 16 as hereinbefore described.

It should further be pointed out that during operation of the rifle, the elongated cylindrical breech bolt 106 may be rotated about its axis by the use of the bolt handle 144, while the cocking piece housing 182 is prevented from rotation due to the engagement of the lug 192 of the cocking piece 190 with the elongated groove 72 in the grooved extension plate 64, The cocking piece housing is retained in its operative position on the elongated cylindrical breech bolt 106 at all times, however, by the threaded engagement of the sleeve with the threaded counterbore 154 in the breech bolt, and by the force exerted by the firing pin compression spring 178 which tends to constantly urge the firing pin mechanism 160 and the cocking piece to which it is connected inwardly in the hollow interior of the elongated cylindrical breech bolt 106.

When the rifle is assembled as illustrated in FIGURES 1-3, the receiver 16 is mounted to the stock 12 in the manner hereinbefore described, and the trigger mechanism 56 is hung from the receiver, also in the manner previously described. The bolt assembly 18 may then be operatively positioned within the receiver 16 by depressing the stop pin 76 so that it does not obstruct passage of the forward end 106a of the bolt through the rear receiver ring 45. In sliding the elongated cylindrical breech bolt 106 through the rear receiver ring 45 of the rear receiver ring 45 of the receiver 16, the

forward locking ribs

108a, 10812, and 1080 of the bolt assembly must be aligned with the slots between the rear locking lugs 50a, 50b, and 500 located within the rear receiver ring. The grooves between the rear locking lugs 50a, 50b, and 50c are only slightly wider than the transverse dimension of the

forward locking ribs

108a, 10817, and 1080 of the bolt assembly 18 so that only a slight clearance is provided as the bolt is pushed through the rear receiver ring 45.

After the bolt 106 has been pushed a slight distance forward into the receiver 16 so that the bolt face begins to emerge from the forward portion of the rear receiver ring 45 into the case ejection port 47, the stop pin 76 may be released so that its spring (not shown) biases it upwardly into the elongated stop pin slot 138 formed in the medial locking rib 132a. The bolt assembly 18 can then be pushed forward in the receiver until the

medial locking ribs

132a, 132b, and 1320 pass through the circumferentially spaced slots or grooves provided between the

rear locking lubs

50a, 50b, and 500 within the rear receiver ring 45 of the receiver 16.

It is important to note that during the forward movement of the breech bolt 106 within the receiver 16, the medial locking ribs 1320, 132b, and 132C continually slide within the grooves provided between the rear locking lugs 50a-50c of the receiver, and continually guide the elongated cylindrical bolt 106 in its sliding movement. The bolt 106 is maintained aligned with its desired path of movement at all times as a result of this cooperating relationship between the rear locking lugs 50a50c of the receiver 16 and the elongated medial locking ribs 13242-1320 provided on the bolt. Near the forward end of its travel, the face or forward end 106a of the breech bolt 106 commences to enter the bore through the forward receiver ring 44, and the forward locking lugs 58a, 58b, and 580 commence to enter the circumferentially spaced grooves which separate the forward locking ribs 10811, 10812, and 1080 carried by the bolt. At this point, a final centering and alignment action of the breech bolt occurs so that its longitudinal axis is precisely aligned with respect to the axis of the barrel 14, and its recessed face is disposed in a plane extending precisely normal to this axis.

During the final portion of the forward travel of the breech bolt 106, the forward locking ribs 10811-108c carried by the bolt move out of the grooves between the forward locking lugs 58a-58c so that the forward locking ribs are positioned forwardly of the forward locking lugs. At this time, the bolt is then rotated about its axis by means of the bolt handle 144, such rotation being through an angle of about 60 or /6 of a complete revolution. This has the effect of seating the bolt in the firing position with the forward locking lugs 58a, 58b, and 58c being immediately behind, and in abutting contact with, the

forward locking ribs

108a, 10811, and 1080. Also, the

medial locking ribs

132a, 132b, and 1320 are backed up by the rear locking lugs 50a, 50b, and 500 which are positioned immediately behind and in contact with the medial locking ribs.

OPERATION In the operation of the breech bolt assembly of the invention, the bolt action may be initially considered in its seated or firing position as depicted in FIGURES l, 2 and 3. In this position, the elongated cylindrical bolt 106 has been reciprocated into the receiver 16 its full length so that the forward locking ribs 108a108c are interlocked with, and immediately ahead of, the forward locking lugs 58a58c. The rear locking lugs 50a-50c in turn are located immediately behind and in abutting contact with the rear ends of the medial locking ribs 132a 1326. The cocking mechanism of the invention is cocked as illustrated in FIGURE 3 where the cocking piece 190 is shown in its rearward position so that the compression spring 178 of the firing pin mechanism is under compression, and the firing pin tip 166 is retracted within the firing pin port 153. The cocking piece 190 is retained in the retracted position by the engagement of the sear 78 with the shoulder 193 formed on the cocking piece lug 192. The retraction of the firing pin mechanism 160 to compress the firing pin compression spring 178 is accomplished during the final rotational movement of the bolt assembly as it is pushed forward to seat the cartridge, since at this time, the final forward movement of the bolt 106 is effected by the camming action of the corners of the forward and rear locking lugs 58a-58c, lugs 50a- 500, respectively, upon the beveled surfaces at the corners of the respective forward and rear locking ribs. 108041080 and 13211-1320. The rotational seating movement of the bolt 106 also brings the cocking piece earn 196 into alignment with the recess carrying the camming surface 150.

In this cocked, ready for firing status of the rifle, the face of the elongated cylindrical bolt 106 extends precisely perpendicular to the axis of the bore through the barrel 14, as has previously been explained. The base of the cartridge seats flatly against the recessed face of the bolt 106 and is engaged by the extractor latch 114.

\Vhen the trigger 24 is pulled to fire the rifle, the sear 78 pivots downwardly to release the cocking piece 190. The cocking piece 190 can move forward until the cocking piece cam 196 strikes the base of the recess in the annular camming cylinder band 143 which defines the camming surface 150. The compression spring 178 then drives the main firing pin shaft 162 forwardly to extend the firing pin tip 166 through the opening 118 in the recessed face of the bolt 106. The firing pin tip 166 thus strikes the percussion cap of the cartridge to fire the cartridge.

As is well understood in the art, with the firing of the cartridge, the gases produced develop an extremely high pressure against the base of the cartridge and the face of the breech bolt 106 in a very short time. It is at this time that the improved construction of the bolt assembly of the present invention offers one of its most important advantages. As a gas pressure is exerted on the face of the elongated cylindrical bolt 106, the bolt tends to be driven rearwardly in the receiver 16. However, no movement of the bolt 106 can occur due to the interlocking relationship between the locking lugs carried by the receiver 16 and the locking ribs carried on the bolt. The high shear strength and resistance to bolt movement within the receiver is provided by the six relatively large areas of rigid support for the bolt which are afforded by the three forward locking lugs 53a, 58b, and 580 and the three rear locking lugs 50a, 50b, and 50c. Moreover, little opportunity for play or vibration of the bolt within the receiver 16 exists due to the extension, in a preferred embodiment of the invention, of the elongated medial locking ribs 13211-1320 over the entire distance which separates the forward locking lugs 581F580 from the rear locking lugs 50a-50c. Thus, the bolt assembly 18 is effectively immobilized, and the large amount of metal which receives and absorbs the recoil and gas pressure forces tending to move the bolt 106 rearwardly with respect to the receiver 16 will permit the rifle to be fired with a maximum degree of safety at all times.

It will be further be noted that the forward locking ribs 108a108c and the medial locking ribs 132a132c are of a radial thickness such that their outer peripheral surface extends into very close proximity to the inner peripheral surface of the forward receiver ring 44 and the rear receiver ring 45 at locations ahead of and behind the respective forward locking lugs 5851-580 and rear locking lugs 50:1-500. Stated in a different way, the forward receiver ring 44 engages the external peripheral portion of both the forward and medial locking ribs 10804080 and 132a132c, respectively, on opposite sides of the forward locking lugs 58a-58c, and the rear receiver ring 45 also engages the external peripheral surface of both the annular camming cylinder band 143 and the

medial locking ribs

132a, 132b, and 1320 on opposite sides of the rear locking lugs 50a50c. Wobbling or canting of the bolt 106 within the receiver 16 is thus prevented, and the perpendicularity of the plane of the bolt face with respect to the axis of the bore through the barrel 14 is developed and maintained during each seating and firing of the rifle. Pattern repeatability and accuracy are thus improved.

Upon completion of the firing of the cartridge, the bolt handle 144 is gripped and is rotated upwardly through an angle of about 60 until the bolt handle strikes the top of the L-shaped guide channel 52 and the stop pin 76 strikes the bottom of the L-slot 146. The grooves a, 1101), and 110c positioned between the forward looking

ribs

108a, 10817, and 1080 are then aligned with the forward locking lugs 58a58c, and the grooves 134a 1340 between the medial locking ribs 132a-132c are aligned with the rear locking lugs 50a-50c. At the same time, the bolt assembly 18 is cammed rearwardly with respect to the receiver by the cam surface 54 provided in the L-shaped guide channel 52. Continued retraction of the bolt assembly 18 is carried out by the shooter pulling rearwardly on the bolt handle 144. During such retraction, the respective locking lugs slide into and pass through the grooves between the respective locking ribs. The dimension of the locking lugs in a transverse or circumferential sense is only slightly less than the dimension of the grooves which separate the respective locking ribs from each other, so that little play or looseness can be developed to permit undesirable rotation of the bolt 106 about its axis as it is being retracted. Instead, the bolt 106 moves easily and smoothly from its seated firing position to the rear within the receiver 16 without binding, and without imparting a jerk to the rifle, so that the user of the rifle can retract the bolt and eject the cartridge with a minimum of difficulty and with maximum speed.

As the bolt face 106a commences to move rearwardly within the forward receiver ring 44, the case of the cartridge which has been fired is withdrawn with the bolt 106 due to the engagement of the extractor latch 114 with the rim of the case. Simultaneously with this engagement, the ejector pin 124 is hearing against the base of the case and tending to pivot the case against the internal wall of the forward receiver ring 44. As soon as the face 106a of the bolt 106 and the forward end of the spent cartridge case have cleared the forward receiver ring 44, there is nothing to restrain the case except the engagement of the rim thereof by the extractor latch 114. The result is that the ejector pin 124 is then able to kick the empty case out of the ejection port 47 in the receiver 16 by pivoting it about the extractor latch 114. During retraction of the bolt 106 to eject the case of the cartridge, interference with the sliding movement of the bolt by the rim of a cartridge being fed to the receiver by the cartridge follower 90 is avoided due to the provision of the rib groove 140 in the elongated medial lockin g rib 1320.

After the forward locking ribs 108a-108c have passed through and cleared the forward locking lugs 58a-58c and have passed over the medial portion 46 of the receiver 16, they cease to afford any guidance to the rearward movement of the bolt 106. The elongated, circumferentially spaced medial locking ribs 132a132c, however, continue to engage and interfit within the grooves provided between the rear locking lugs 5001-500 as the bolt continues its rearward movement. Thus, the medial locking ribs 132a132c continue to provide a guiding action for the bolt throughout its rearward travel.

When the bolt assembly has been retracted to its limit of travel as determined by the abutment of the stop pin 76 against the terminus of the stop pin slot 138, the sear 78 has been returned by its sear spring (not shown) to the elevated, cocking pieceengaging position, and the trigger 24 has been returned to a forward position preparatory to firing.

In the fully retracted position of the bolt 106, a fresh or unfired cartridge can be fed through the rectangular opening 48 in the bottom of the receiver from the magazine box 20. Then, as the bolt 106 is pushed forwardly to reload the rifle and place it in the firing position, the face of the bolt engages the base of the case of the cartridge, and pushes the cartridge forwardly through the forward receiver ring 44. The forward movement of the bolt is again a smooth and even motion as a result of the guiding action afforded by the elongated medial locking ribs 132a132c. The bolt 106 will not hang or bind during its seating movement, thus enabling the hunter to maintain a smooth reloading action, and to get off second, third, and fourth shots rapidly and accurately.

A modified embodiment of the bolt assembly 18 is depicted in FIGURES 17 and 18 of the drawings. Since certain portions of the modified bolt assembly are identical to structural elements referred to in discussing the bolt assembly 18 depicted in FIGURES 12-16, identical reference numerals will be utilized to identify the same structures where they appear in FIGURES 17 and 18. Thus, the modified bolt assembly of these figures has been designated by reference numeral 204, and includes an elongated cylindrical bolt member 206 which has a hollow interior defining a bore 152, a firing pin channel 156, and a firin pin port 158 which terminates in a firing pin aperture 118, as shown in FIGURE 18. A firing pin assembly 160 is positioned in the hollow interior of the bolt 206. The elongated cylindrical bolt 206 has, extending radially outwardly therefrom, a plurality of elongated, circumferentially spaced medial locking ribs 13251-1320 arranged in substantially the same manner and functioning as has been hereinbefore described.

Axially spaced forward of the medial locking ribs 132a132c and disposed at the forward or face end of the bolt 206 are a plurality of circumferentially spaced forward locking

ribs

208a, 208b, and 2080. It will be noted in referring to FIGURES 17 and 18 that the forward locking ribs 208a and 2081: have one of their side edges cut away at a fairly sharp angle to accommodate an elongated spring plate 210 forming a portion of an extractor mechanism. At its forward end, the springplate 210 carries an extractor latch 212 having a beveled front edge for camming the rim of a cartridge case under the extractor latch and into a central recess 214 formed in the forward end or face of the bolt 206. The spring plate 210 is bent to form a protuberant portion toward the rear end thereof, and spaced rearwardly from a pivot pin 2116 passed through the spring plate and through the walls of the cylindrical bolt 206. A spring 218 is provided beneath the rear portion of the spring plate 210 so that the spring plate is biased by the spring to a position in which the extractor latch 212 is at a position which is relatively inward radially with respect to the position which it obtains when the protuberant portion of the spring plate is depressed into the spring plate slot against the bias of the sprin 218. Positioned adjacent the extractor latch 212 is the protuberant end portion of an ejector pin 220 which has a shank ex tending into an ejector pin bore 222. A compression spring 224 is positioned in the rear portion of the bore 222 and biases the ejector pin 220 to an outwardly extending position, as shown in FIGURE 17.

On the opposite side of the bolt face recess 214 from the ejector pin 220 and the extractor latch 212, an adjustable extractor mechanism designated generally by reference numeral 228 is located. The adjustable extractor mechanism 228 includes an extractor arm 230 having a tapered latch portion 232 for engaging the rim of the cartridge case. The rear end of the extractor arm 230 is pivotally secured in a slot in the forward locking rig 2080 by a pivot pin 23 4. A small helical spring 236 is positioned in a radially inwardly extending recess which communicates with the slot formed in the rib 208a, and the spring surrounds the shank of an adjustment screw 240 which is threaded into the bolt 206. By adjusting the position of the adjustment screw 240 with respect to the cylindrical bolt 206, the grip or engagement exerted by the extractor latch 232 upon the rim of the cartridge can be varied so as to cause the extractor mechanism 228 to release the rim of the cartridge more easily.

In the operation of the modified bolt assembly 204 depicted in FIGURES 17 and 18, when the bolt 206 is retracted or pulled rearwardly in the receiver 16 after firing of the cartridge, the cartridge is engaged by both the extractor latch 2.12 and the extractor latch 232. At this time, the base of the case forces the ejector pin 212 into its bore 222, and loads the ejector pin spring 224 in compression. Due to the gripping action of the dual extractor latches 212 and 232, the cartridge case is retained centered in the face of the bolt 206, and its axis is aligned with the axis of the barrel 14. The cartridge case thus does not become canted within the forward receiver ring 44, as is the case where a single extractor mechanism is provided. Wear of the internal walls and locking lugs of the receiver is thus obviated, since the cartridge case does not touch the receiver at any point as it is extracted.

As the retracting or withdrawing movement of the bolt assembly 204 is continued, the forward portion of the bolt 206 approaches the rear receiver ring and the portuberant portion of the spring plate 210 is depressed by contact with one of the rear locking lugs within the rear receiver 45. Depression of the portuberant portion of the spring plate 210 results in the extractor latch 212 becoming disengaged from the rim of the cartridge case. This permits the ejection pin 220 to snap forward under the biasing influence of the compression spring 224 so that the cartridge case, which by this time is aligned with the ejection port 47 in the receiver 16, is pivoted about the point of engagement with the extractor latch 232, and is thrown sideways from the ejection port 47.

It is at this time that another advantage of the modified bolt assembly 204 shown in FIGURES 17 and 18 is manifested. Thus, the path of ejection and distance of ejection of the spent cartridge case can be controlled by adjustment of the adjusting screw 240 forming a portion of the extractor mechanism 228. When the screw 240 is screwed downwardly to force the extractor latch 232 further inwardly in a radial sense with respect to the recess 214, a firmer engagement of this extractor latch with the rim of the cartridge is developed. The cartridge will therefore not be ejected over as great a distance as will be the case when the adjustment screw 240 is screwed to a position in which its head is a greater radial distance from the axis of the bolt 206. It will be appreciated by those skilled in the art that this feature of the modified bolt assembly 204 shown in FIGURES 17 and 18 has value where a rifle is at times used for target shooting and it may be desired to recover the brass for reloading or examination, and is used on other occasions for hunting when it is desired to have the cartridge cases thrown well clear of the rifle and the hunter.

Although certain preferred embodiments of the present invention have been herein described in order to provide an example of the manner in which the invention is to be practiced, it will be understood that various modifications and structural changes can be imparted to the described and depicted structures without departure from the basic principles of the invention.

What is claimed is:

1. A bolt action for a rifle comprising:

an elongated receiver adapted for securement to a barrel and having a forward receiver ring; a rear receiver ring; and a medial portion joining said receiver rings;

a plurality of circumferentially spaced, radially inwardly extending forward locking lugs secured inside said front receiver ring and separated from each other by axially extending grooves;

a plurality of circumferentially spaced, radially inwardly extending rear locking lugs secured inside said rear receiver ring and separated from each other by axially extending grooves, said rear locking lugs being axially aligned with said forward locking lugs;

an elongated cylindrical bolt member rotatably and slidably mounted in said receiver and having a forward end and a rear end;

a plurality of circumferentially spaced forward looking ribs extending radially outwardly from the forward end of said bolt member and having circumferentially spaced grooves therebetween, said forward locking ribs being dimensioned to pass between said forward locking lugs in the grooves between said forward locking lugs during the sliding motion of said bolt member in said receiver, and being spaced circumferentially on said bolt member for aligned, abutting contact with the forward side of said forward locking lugs when said bolt member is rotated in said receiver, the axially extending grooves separating said rear locking lugs being dimensioned to pass said forward looking ribs during the sliding motion of said bolt member in the receiver; and

a plurality of elongated, circumferentially spaced, axially extending medial locking ribs extending radially outwardly from a medial portion of said bolt member and spaced axially from said forward looking ribs toward the rear end of said bolt member by a distance at least as great as the axial dimension of said forward locking lugs, said medial locking ribs having axially extending grooves therebetween and being axially aligned with said forward looking ribs, and said medial locking ribs having a transverse dimension permitting them to pass between said rear locking lugs in the grooves between said rear locking lugs during the sliding motion of said bolt member in said receiver, and being spaced circumferentially on said bolt member for aligned abutting contact with the forward side of said rear locking lugs when said bolt member is rotated in said receiver.

2. A bolt action as defined in claim 1 wherein the length of each of said elongated medial locking ribs is substantially equivalent to the distance separating the forward and rear locking lugs and covers a major portion of the total length of the bolt member.

3. A bolt action as defined in claim 1 wherein the circumferential dimension of each of said medial locking ribs is substantially equal to the circumferential dimension of each of said rear locking lugs and is less than the transverse width of the grooves between said rear locking lugs by the minimum amount necessary to permit sliding movement of said medial locking ribs in the grooves between said rear locking lugs.

4. A bolt action as defined in claim 1 wherein said forward end of the bolt is recessed, and wherein said bolt action is further characterized as including:

a first extractor mechanism positioned on one side of the recess in the forward end of the bolt member;

a second extractor mechanism positioned on the opposite side of the recess in the forward end of the bolt member from the first extractor mechanism; and

an ejector positioned between said first and second extractor mechanisms.

5. A bolt action as defined in claim 1 wherein said receiver is further characterized as including a backstrap positioned on the opposite side of said rear receiver ring from said forward receiver ring and projecting from said rear receiver ring in the opposite direction from said medial portion of the receiver.

6. A bolt action as defined in claim 1 wherein one of said medial locking ribs has an elongated stop pin slot extending axially in the central portion thereof over a major portion of the length of said one medial locking rib, and is further characterized in having an arcuately cross-sectioned, axially extending rib groove in one longitudinal edge thereof to facilitate passage of said bolt member over a cartridge in the upper portion of a magazine box.

7. A bolt action as defined in claim 1 and further characterized as including:

a bolt extension and camming cylinder surrounding and formed integrally with said elongated cylindrical bolt member at the rear end thereof, said bolt extension and camming cylinder including a camming cylinder band around said bolt member and spaced axially along said bolt member from said medial locking ribs by an axial distance at least equal to the axial dimension of said rear locking lugs whereby said rear locking lugs can be positioned between said medial ribs and said camming cylinder band; and

a bolt handle extending outwardly from said camming cylinder band.

8. A bolt assembly as defined in claim 7 wherein said camming cylinder band is characterized in having a rear face, and a plurality of camming surfaces in said rear face, and said action further includes:

a cocking piece housing rotatably mounted on the rear end of said bolt member;

a cocking piece positioned in said cocking piece housing and rotatable with said cocking piece housing relative to said bolt member, said cocking piece including a lug projecting from said cocking piece housing for cooperation with a trigger mechanism, and further having a cam projecting from said cocking piece housing positioned for riding on said camming surfaces; and

a firing pin mechanism in said bolt member and secured to said cocking piece.

9. A bolt action as defined in claim 1 wherein one of said forward locking ribs has an axially extending extractor slot therein, and wherein said bolt action further includes an extractor mechanism comprising an extractor latch at the forward end of the bolt member and a spring metal finger extending into said extractor slot.

10. A bolt action as defined in claim 3 wherein the length of each of said elongated medial locking ribs is substantially equivalent to the distance separating the forward and rear locking lugs and covers a major portion of the total length of the bolt member.

11. A bolt action as defined in claim 10 wherein one of said medial locking ribs has an elongated stop pin slot extending axially in the central portion thereof over a major portion of the length of said one medial locking rib, and is further characterized in having an arcuately crosssectioned, axially extending rib groove in one longitudinal edge thereof to facilitate passage of said bolt member over a cartridge in the upper portion of a magazine box.

12. A bolt action as defined in claim 11 and further characterized as including:

a bolt extension and camming cylinder surrounding said elongated cylindrical bolt member at the rear end thereof, said bolt extension and camming cylinder including References Cited UNITED STATES PATENTS 3/1896 Mondragon 42-16 6/ 1940 Williams 4225 5/1956 Ruple 4218 8/1957 Hellman 4216 12/1961 Weatherby 4216 0 BENJAMIN A. BORCHELT, Primary Examiner C. T. JORDAN, Assistant Examiner U.S. Cl. X.R.