EP0130253A2

EP0130253A2 - Receiver for bolt action firearm and method of manufacture

Info

Publication number: EP0130253A2
Application number: EP83304997A
Authority: EP
Inventors: William Batterman Ruger
Original assignee: Sturm Ruger and Co Inc
Current assignee: Sturm Ruger and Co Inc
Priority date: 1983-05-02
Filing date: 1983-08-30
Publication date: 1985-01-09
Also published as: ES277149Y; MX156730A; EP0130253B1; JPS59202400A; JPH0366600B2; DE3378593D1; BR8304628A; AU1738783A; PT77236B; AU562369B2; ES277149U; ES8406256A1; PT77236A; AR231353A1; ES525211A0; EP0130253A3; KR850001999A; KR860000045B1

Abstract

A receiver (12) for a bolt action rifle having at least one seat surface (27a or 28a) for seating a bolt lug (27 or 28). The seat surface is positioned on a rearward portion (24) of the receiver adjacent a breech opening (30) and the surface is formed by movement of a broach (35) through such opening.

Description

This invention relates to receivers used in rifles which receivers have seating surfaces against which bolt lugs are positioned and to the method of manufacture of the receiver with such seating surfaces.
Prior rifle receivers have had spaced apart lug seating surfaces which were so positioned that manufacture of the receiver including the lug seats required numerous operational steps and often meeting required tolerances was difficult.
The present invention overcomes weaknesses of the prior art by providing an improved receiver and method of manufacture.
According to the present invention there is provided a receiver for a bolt action firearm having a barrel, a bolt with lugs and a stock characterised in that there is provided:

a) a receiver housing having a forward portion adapted to engage the barrel, a rearward portion adapted to engage the stock and a hollow breech portion between said forward and rearward portions;
b) at least one seat surface on the rearward receiver portions for mating with a lug on the bolt, said surface being formed by a single stroke of a broach cutting means.

According to a further aspect of the present invention there is provided a method of manufacture of a receiver for a bolt action firearm, characterised in that the method includes the steps of:

a) forming a metal receiver blank having a rearward portion with a breech opening adjacent thereto; and
b) passing a broach means through the breech opening to remove metal from the rearward portion to form at least one bolt lug seat thereon.

As will be apparent from the foregoing, the invention concerns the formation of a receiver having forward, breech opening and rearward portions with one or more bolt lugs seats positioned on the rearward portion so that they can be readily formed by the simple broaching operation. The broach is passed through the breech opening to machine the lug seats.
It is a feature that the lug seats may after forming lie in a plane perpendicular to the bore of the rifle barrel.
It is also a feature that the receiver blank can be cast with a controlled amount of metal material in the areas adjacent the seats to be formed such that the seats can be formed in a single stroke of a broaching tool.
An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:-

Fig. 1 is a side elevational view of a rifle, partially broken away, to show portions of the bolt including the bolt lugs and the receiver of this invention;
Fig. 2 is a plan view of the rifle showing the receiver;
Fig. 3 is a plan view of the receiver of the invention during manufacture with the broach shown in section; and
Fig. 4 is the section along line 4-4 of Fig. 3.

Referring to Figs. 1 and 2, rifle 10 includes barrel 11, receiver 12, breech bolt assembly 13, bolt 14, bolt handle 16, bolt head sleeve 17 and cocking piece 19. Also shown are stock 21 and tang 22.
Receiver 12 includes forward portion 23, rearward portion 24 and a hollow breech portion 26. Bolt 14 carries upper bolt lug 27 and lower bolt lug 28. Forward receiver portion 24 has upper lug seat 27a and lower lug seat 28a. Bolt lugs 27 and 28 engage receiver lug seats 27a and 28a when the bolt is in its closed position (Fig. 1).
Turning to Figs. 3 and 4, the method of manufacture of receiver lug seats 27a and 28a is shown in which a broach 35 is positioned in breech opening 30. Initially, the receiver blank is formed by investment casting, forging or other method. Portions of the receiver blank are then finished by machining, grinding or otherwise as known in the art. As part of this manufacturing process, the forward areas 31, 32 of the rearward portion 24 are partially removed by machining to provide the desired location of surfaces 27a and 28a. In the practice of this invention, the receiver blank includes metal material in the forward areas 31, 32 of the rearward receiver portion 24 so that metal removed from area 31, 32 by machining provides surface seats 27a, 28a of proper area and location within acceptable tolerances. Further the method of manufacture provides that the volume of metal material in areas 31, 32 preferably does not exceed that which can be machined by one stroke of a broach tool. By controlling the amount of metal in areas 31, 32 seats 27a, 28a can be formed in one broach stroke.
Referring to Fig. 4, broach tool 35 has broach teeth 36 which machine metal from the forward areas 31, 32 as broach 35 is moved downwardly (see arrow in Fig. 4). Broach 35 carries sufficient teeth of selected size, length and angle such that the machining of forward areas 31, 32 to form seat surfaces 27a and 28a is accomplished in one downward stroke. Broach 35 is preferably positioned to move perpendicularly to the axis of the barrel or a line parallel thereto (see centre line C/L of Fig. 4). With broach 35 so oriented during its machining stroke, seat surfaces 27a and 28a will be in the same plane and each seat surface equidistant from the end of the barrel 11.

Claims

1. A receiver for a bolt action firearm having a barrel (11), a bolt (14) with lugs (27, 28) and a stock (21) characterised in that there is provided:-

a) a receiver housing having a forward portion (23) adapted to engage the barrel (11), a rearward portion (24) adapted to engage the stock (21) and a hollow breech portion (26) between said forward and rearward portions;

b) at least one seat surface (27a or 28a) on the rearward receiver portions(23) for mating with a lug (27, 28) on the bolt (14), said surface being formed by a single stroke of a broach cutting means (35).

2. A receiver as claimed in claim 1, having two spaced-apart lug seats (27a, 28a) which seats lie in a single plane.

3. A method of manufacture of a receiver for a bolt action firearm, characterised in that the method includes the steps of:-

a) forming a metal receiver blank having a rearward portion (24) with a breech opening (30) adjacent thereto; and

b) passing a broach means (35) through the breech opening (30) to remove metal from the rearward portion (24) to form at least one bolt lug seat (27a or 28a) thereon.

4. A method as claimed in claim 3, in which the broach means (35) is passed through a plane perpendicular to the centre line of a barrel of the firearm.