Abstract:
An improved ammunition feed and guide mechanism for an automatic gun barrel weapon such as an automatic machine cannon. This mechanism includes a breech mechanism mounted in a housing. The breech mechanism includes a breech body driven by a pair of rollers rotatably mounted in the housing parallel to the middle longitudinal axis of the housing. Each roller has a driving ramp disposed on its periphery and the breech body is provided with a pair of roller bearings respectively engaging the driving ramps of the rollers so that the breech body is linearly reciprocated between loading and firing positions via the rotation of the rollers and the engagement of the roller bearings in the driving ramps thereof. The pair of rollers are driven by means independent of the propulsion energy of the fired projectiles. When the breech body is in the firing position, the roller bearings and driving ramps are maintained substantially free from the influence of the axially acting recoil forces brought to bear on the breech body during firing.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a feed and guide mechanism which is rigidly secured to a linearly moving breech mechanism of an automatic gun barrel weapon. 
     Such type of feed and guide mechanisms is already known and described in U.S. Pat. No. 4,167,888. In this known automatic weapon with external drive motor there is provided a gun barrel whose axis is fixed with respect to a breech casing. A cartridge chamber is disposed rearwardly of the gun barrel and is adapted to coact with a breech mechanism. A rotary drum, whose peripheral surface has helical grooves forming a drive ramp of closed contour, is mounted in the breech casing. A follower member cooperates with the drive ramp and is rigidly connected to the breech mechanism. The arrangement includes two rods disposed above the rotary drum parallel to the longitudinal gun barrel axis and serve for guiding the breech mechanism in a nonuniform manner for counter recoil and recoil movements. The follower member is constructed as a rotatable plate mounted on the breech mechanism, which supports in a plane two rotatable rollers for coaction with the drive ramp disposed on the rotary drum. There are disposed on this plate at least two flat guide surfaces for the alternate coaction with at least one also flat guide surface disposed on the housing or breech casing. Thereby the two rollers mounted on the plate are specifically aligned in the cross-over region of the control groove so that the follower can traverse without malfunctioning. The rotary drum carries out a firing cycle in n revolutions, whereby n is at least equal to 3, but advantageously is equal to 4. Thereby there results n-1 cross-over regions for different branches of the drive ramp. 
     This known arrangement has the following drawbacks: 
     It requires first of all a considerable height in view of two cross-over regions per firing cycle. An additional guiding in the housing is required on corresponding sections of the breech path for the plate which is rotatably mounted on the breech body. Consequently, a mounting adjustment in a delayed manner is necessary. Additionally the feed forces are introduced via the support shaft of the plate unilaterally into the breech mechanism and, as a result of the ensuing increased wear caused by friction, malfunctioning may occur. Finally, the firing bolt arranged in the breech body is disadvantageously inertially actuated and consequently must have a sufficiently large mass which is a further drawback to be considered. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide an arrangement of the afore-described type for an automatic weapon, which has a reduced constructional height and dimension, as compared to the prior art devices, and which is also capable of uniformly introducing the forces for moving the ammunition thereby reducing the frictional wear. Moreover, the firing motion of the firing bolt in the arrangement of the invention is independent from its moment of inertia. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     With these and other objects in view, which will become apparent in the following detailed description, the present invention, which is shown by example only, will be clearly understood in connection with the accompanying drawing, in which: 
     FIG. 1 is a straight breech arrangement in accordance with the invention whose controlled guidance arrangement is illustrated in perspective with cut-away portions for purpose of clarity; 
     FIG. 2 is a cross-sectional view along plane II--II in FIG. 1, wherein the illustration is at an enlarged scale; 
     FIG. 3 is a plan cross-sectional view along the plane III--III as illustrated in FIG. 1, which plane is defined by the line III--III in FIG. 2; 
     FIG. 4 illustrates a breech body illustrated in a front elevational view at an enlarged scale; 
     FIG. 5 illustrates the breech body in cross-section along line V--V in FIG. 4; 
     FIG. 6 illustrates the breech body in cross-section along VI--VI in FIG. 4; and 
     FIG. 7 illustrates a diagrammatic operational sketch for illustrating more clearly the positive firing bolt guiding by means of a simplified cross-sectional sketch along the line VI--VI in FIG. 3 at a reduced scale in which insignificant details have been omitted. 
    
    
     DETAILED DESCRIPTION 
     In order to take into the account the substantially mirror-symmetrical arrangement those parts which are equivalent on both sides of the plane of symmetry have been designated with identical reference numbers. Only in those instances when it serves for a better understanding of the arrangement of the invention have the corresponding reference numbers been complemented with the designation l for left and r for right. 
     Referring now to FIGS. 1 and 3, the pertinent portion of a housing 10 extends longitudinally along a middle longitudinal axis GA (which lies in the aforementioned, non-illustrated vertical plane of symmetry) between a forward support region 11 and a rear support region 13. The housing has a pair of vertical longitudinally extending side walls 12. In the forward support region 11 of the housing 10 there are disposed lateral guide grooves 14 for slidably receiving and guiding respective blocking sliders 24; respective front supports 20; and in the middle a gun barrel receiving recess 16 for a gun barrel 40 having a longitudinal gun barrel axis SA. Moreover, the gun barrel recess 16 is provided with a rear end surface 42 and a loading chamber 44. A left transverse surface 17l and a right transverse surface 17r are adjoined by guide surfaces 18l, 18r which are parallel to the afore-mentioned vertical symmetrical plane. These guide surfaces 18l, 18r are limited at their rear by corresponding edges 19 which in turn limit forwardly the guide recesses 14. The front support 20 is mounted in a friction-reducing support element 21 and receives a rearwardly extending stub shaft 66; the front support 20 has a peripheral cylindrical bearing support surface 67 which coacts with support element 21 and which extends from the main portion of a cylindrical roller 50l, 50r which roller has a central rotational axis 51l, 51r. The gun barrel longitudinal axis SA, the housing middle axis GA and the rotational axis 51l, 51r are parallel to each other. 
     A predetermined cam groove (also referred to as driving ramp) is disposed in the peripheral region of the roller 50 which is in the form of an endless entraining groove 53 having a first entraining surface 54.1 and a second, corresponding radial entraining surface 54.2. To these surfaces there are adjoined from below at a right angle a first lateral surface 55.1 and a second lateral surface 55.2. Not further designated edges of the lateral surfaces 55 define a central guide control groove 56 which has a rectangular cross-section with a bottom surface 57. The entraining groove 53 and the thereto joined guide groove 56 merges into a forward region 58 of the entraining groove (which extends transverse to the rotational axis 51 at an angle of 90 degrees) which forward entraining groove region 58 in the region of the front support 20; this entraining groove 53 has also a rear region 62. The forward entraining groove region 58 and the rear entraining groove region 62 are joined to each other by the groove branches 59 and 61. This joining of the end regions 58 and 62 of the entraining grooves by means of the branches 59 and 61 is effected in a mutually opposite sense by a mutual cross-over in a cross-over region 60, whereby the right-hand screw direction of one branch on the roller 50l corresponds to the left-hand screw direction of the corresponding branch on the roller 50r (and conversely). As will be described hereinafter with greater particularity, the width of the forward entraining groove region 58 of the entraining groove 53 and the guide groove 56 disposed therein are larger than in the remaining extent of these grooves. The roller 50 is in the region of its stub shaft 66 provided with a central axial receiving bore 68 for receiving a rearwardly extending pin of a element 70 in the receiving bore 68 in a predetermined position by form-locking means of a locking element 73. The constant-diameter-eccentric-projection 74 engages in a control recess 28 (see FIG. 2) which is laterally defined by parallel, vertical control surfaces 29 and 30 for coacting with the peripheral surface 75 of the constant-diameter-eccentric-projections 74. The control surface (inner) 29 of the recess 28 is in contact with the projection 74. In the direction of the housing middle axis GA there is slidably mounted in the guide recess 14 a rear adjusting member 26. On the rear peripheral support surface 76 of the roller 50 there is provided in the housing 10 a rear bearing support surface 22; the latter is not illustrated in detail and its position is only referred to by means of a reference line and arrow and reference number. Past the rear support surface 76l, 76r there extends a shaft 77l, 77r, which in the region of its not further designated free end, in a manner not illustrated in detail is rotatably supported in the rear support region 13 of the housing 10, and on which there is respectively coaxially mounted a gear wheel 78l, 78r. The wheel 78l has a larger rim width 78&#39;l which meshes with a toothed gear wheel of a non-illustrated auxiliary driving arrangement, arranged outside the housing 10, which is fed with a source of energy not forming part of the weapon (which will be described hereinafter). In addition thereto the gear wheel 78l meshes with an intermediate gear wheel 80 and, via the latter and an intermediate gear wheel 82 meshes with the gear wheel 78r in a form-locking manner. A straight breech body guide arrangement is provided which has a a pair of first horizontal support rails 31, equally spaced from respective side of the adjoining roller and the common middle housing axis GA, each rail 31 of which extends longitudinally through the housing 10 and slidably supports the breech body 90 so as to provide a straight breech body guiding. The guide rails 31 are adjoined on their exterior side by vertical upwardly extending bearing surfaces 32. A further horizontal guide rail is not illustrated for reason of clarity but is in the herein following portion of the specification mentioned. 
     There is illustrated in FIG. 1 a rigidly secured (on the housing) cartridge casing expeller 36 having a left and a right correspondingly downwardly extending finger 37l and 37r which extends towards the breech body guide arrangement. In the region of the upper side of the housing 10 there is provided a non-illustrated cartridge feed (driven with an external source of energy relative to the weapon). Coacting with this ammunition feed arrangement is a feed surface 38 which will be described hereinafter This feed surface is illustrated in FIG. 4 by means of a dash line as is illustrated a cartridge P by means of a circular dash line. Between the two support rails 31l and 31r there is disposed in the region below the cartridge casing expeller 36 a cartridge ejector 35. The breech body 90 is arranged for longitudinal axial movement within the housing 10. This breech body 90 extends along a longitudinal axis 91 from a head 93 via a middle portion 100 to a rear portion 101 and a tail edge 102 of the rear portion 101. The head 93 is substantially defined by a corresponding spherical upper side 93&#39; and under side 93&#34; and a forward end middle surface 95 and again corresponding spherical left and right side surfaces 96l and 96r. In the forward end edge region 94 there is arranged, upwardly and in the middle between two ejection recesses 97l&#39; and 97r&#39;, an introduction finger 97. In the ejection region of the longitudinal axis 91 in the end middle surface 95 there is disposed a hereinafter to-be-described firing bolt passage 99. The side surface 96l and 96r limit a corresponding shoulder 98l, 98r, extending transversely to the longitudinal axis 91, which merges inwardly with the middle portion 100, which integrally connects the head 93 with the rear portion 101. This rear portion 101 includes a left arm 110l and a right arm 110r, both of which extend laterally and each of which is defined peripherally by a spherical surface 111. Rearwardly the rear portion is limited by the aforementioned rear edge 102. A central longitudinal bore 103 extends along the longitudinal axis 91, which bore has a stepped inner diameter and includes a forward frusto-conically shaped portion whose inner rear extent is defined by a rear edge 106. This rear edge 106 is adjoined by a forward bore region 104 having an inner diameter d 1 . The stepped bore is provided by means of an annular portion 105. Adjoining this annular portion is a rear region 108 of the central bore 103 which has an inner diameter d 2  which is larger than d 1  (the diameter of the forward region 104 of the bore 103). A cross bore 112l, 112r crosses at an angle of 90 degrees central bore 103, which cross-bore at its opposite ends passes through the two end faces 111l and 111r. Each cross bore 112 extends along a transverse axis 92 and accommodates therein a bearing cylinder 113 which has an inner end face 114 disposed in the cross-over region between the cross bore 112 and the central bore 103. Each bearing cylinder 113 extends past the corresponding spherical end face 111 and has immediately adjacent to the end face 111a bearing surface 115 for supporting a guide roller bearing 119. Adjoining the bearing surface 115 is an outer bearing surface 116 for supporting a second entraining roller bearing 120, whereby the outer diameter of the second roller bearing is smaller than that of the first guide roller bearing 119. The bearing surface 116 extends up to an end face 117 of the bearing cylinder 113. A second cross-bore 133 extends parallel to the transverse axis 92 adjacent to the rear edge 102 which transverse bore 133 crosses the rear region 108 of the central bore 103 at an angle of 90 degrees and which receives therein a tightening pin 134. There is movably mounted in the central bore 103 a firing pin or bolt 150 having a longitudinal axis 151 which is adapted for axial movement within the central bore 103. A rear control portion 155 of the bolt 150 is disposed in the rear region 108 of the central bore 103 and has an exterior diameter which mates with the interior diameter d 2  of said rear region. This rear portion of the firing bolt 150 is limited at its forward extent by means of an annular portion 154 which is disposed at a predetermined axial distance from the annular portion 105 of the central bore 103 and is transversely disposed with respect to the longitudinal axis 151. 
     The annular portion 154 is adjoined by the forward shaft portion 152 (whose outer diameter corresponds to the inner diameter d 1  of the forward region 104 of the central bore 103) and extends forwardly up to an edge 152&#39; at which edge the forward shaft 152 merges into the frusto-conical nose portion 153. Near the rear end of the rear control portion 155 there is disposed a recess 162 which includes a guide surface 163 being limited by a common edge 164 with an end face 165. A spiral holding spring 166 surrounds the forward shaft 152 and abuts with its respective ends against the annular portions 105 and 154. By pre-compressing the holding spring 166 the firing bolt 150 is maintained in an inoperative position by the tightening pin 134 and its coaction with the guide surface 163 and the bolt 150 is also secured against rotation in this way. In its inoperative position a left recess 156 and a right recess 157 of the rear control portion 155 is positionally adjusted in a predetermined manner with respect to the corresponding cross bores 112l and 112r. The recess 156 is limited by a forward edge surface 158 and a rearward edge surface 159. The recess 157 is limited by a forward edge surface 160 and a rear edge surface 161. The corresponding counter surfaces 158 . . . 161 are formed as vertical prism surfaces, whereby they encompass pairwise with each other and individually with a vertical plane which includes the longitudinal axis 151 a corresponding acute angle. The recess 156 is arranged to the left and the recess 157 is arranged to the right with respect to the longitudinal axis 151, whereby the recess 157 is displaced relative to the recess 156 by a predetermined axial distance in the direction of the annular step 154. An inner bore surface 118 of the bearing cylinder 113 surrounds a control bolt 124 adapted to coact with a control support shaft 121, both of which have circular cross-sections and are movably arranged within the bearing cylinders 113. The control bolts 124l, 124r coact with their control surfaces 125 and 126 in the recesses 156, 157. The control surfaces 125 and 126 are also formed as prismatic vertical surfaces for purposes of coacting with the corresponding counter surfaces 158 and 159 respectively 160 and 161. The control bolt 124 with the end 127 thereof which is remote from the firing bolt 150 contacts the control support member 121, whereby one or both ends 122, 127 of the bolt 124 and shaft 121 has preferably a spherical shape. At the exterior end 123 of the control support shaft 121 there is secured a guide element 128. By means of the mutual arrangement of the control surfaces 125 and 126 as well as the counter surfaces 158 . . . 161 the control bolts 124 may move along a longitudinal axis 92 but cannot rotate about the same. In contradistinction thereto, the control support member 121 can rotate about axis 92 as well as move axially. This will be further described hereinafter. The guide element 128 projects past the exterior end face 117 of the bearing cylinder 113 and has a gliding skid 129 with two identical free ends, which are defined by means of deflecting surfaces 138. Via an exterior surface of the gliding skid 129, which is not illustrated in detail, the control surface 130 projects outwardly. This control surface is disposed on the transverse axis 92 and is limited by an end surface 139 and two deflecting inclines 140. The length of the gliding skid 129 is larger by a predetermined amount than the exterior diameter of the immediately adjacent entraining roller bearing 120. The breech body 90 rests with the exterior regions of its spherical underside surface 93&#34; on the support rails 31. For guiding the exterior region of the spherical or round upper side surface 93&#39; one of the support rails 31l, 31r is adapted to coact with the breech body 90 over which rail it is disposed at a vertical distance parallel to the breech body, which rail is, as has been stated herein-above, for purpose of clarity not illustrated in detail. 
     This breech body is laterally, in the region of its round side surfaces 96l and 96r and the round or spherical guide end faces 111l and 111r guided along the bearing surfaces 32l and 32r. The breech body 90 rests with its guide roller bearings 119l, 119r on the track or rail 34l and 34r. The entraining roller bearing 120l and 120r engage in the entraining groove 53l and 53r and the guide elements 128l and 128r engage in the control guide grooves 56l and 56r. 
     MANUAL OF OPERATION 
     In the initial starting condition for the operation of the arrangement the breech body 90 is in its forward end position and engages with its guide elements into the guide control groove 56 in the roller 50 so that its entraining roller bearing 120 is disposed in the entraining groove 53 in its forward end position region 58l and 58r, as is illustrated in FIGS. 1 and 3. No cartridge P is disposed in the feed plane 38 over the middle of the feed position. The non-illustrated auxiliary external driving arrangement which is driven by an external source of energy, drives the gear wheel 78l for rotating the roller 50l in the clockwise direction (arrow 83) and the roller 50r in the counter-clockwise direction (arrow 84). The driving arrangement is also operatively connected with the cartridge feeder, whereby between the latter and the rollers 50l. 50r a positive drive is furnished. As a result of the afore-described rotation of the rollers the blocking sliders 24l and 24r are adjusted in the direction of the arrows 25.1 (FIG. 3) and expose the shoulders 98l and 98r on the breech body 90. The entraining roller bearings 120l and 120r arrive in the corresponding entraining groove branch 59.1 and by way of the mutual positive drive connection there results an axial movement of the breech body 90 in the direction of an arrow 90.1 (see FIG. 3). The guide element 128, which is rotationally mounted via the control support member 121 in the bearing cylinder 113, follows the course of the guide groove 56 with the aid of the entraining roller bearing 120 while continuously adapting itself to the angularity with respect to the rotational axis 51. When entering into the cross-over region 60 the length of the gliding skid 129 engenders a well-defined transfer of the entraining roller bearings 120l, 120r from the branch 59.1 into the branch 59.2 of the entraining groove 53. In the meantime the positively step-wise controlled cartridge feeder (not illustrated) feeds in a feed step a cartridge P into the cartridge feed plane 38 (see FIG. 4) over the middle of the arrangement into the feed position and during the further recoil of the breech body 90 the ejection fingers 37l and 37r pass through the recesses 97&#39;l and 97&#39;r, so that a non-illustrated empty cartridge casing looses a positive linkage with the breech body 90, provided at the bottom side by means of the extractor 135 and falls through the cartridge casing ejector 35. During the continuous further rotation of the rollers 50l and 50r the breech body 90 arrives in its rearward end position, in which the entraining rollers 120l and 120r and the guide elements 128l and 128r are arranged on the rearward end support region 62l, 62r of the entraining groove. The guide elements 128l, 128r follow the course corresponding to that of the central guide groove 56 and for purposes of reversing the movement of the breech body 90 are positioned in a vertical transverse position relative to the rotational axes 51l, 51r. The control bolt 124 retains its position, that means it does not rotate. For the purpose of reversing the movement of the breech body 90 in the direction of an arrow 90.2 the positive connecting means of the breech body 90 arrives in the corresponding branch 61.1 of the grooves disposed on the rollers 50. During the further forward movement of the breech body 90 its introducing finger 97 arrives at the bottom of the cartridge P located in the plane 38 and entrains it until it is introduced into the loading chamber 44. As the breech body 90 approaches its forward end position, the blocking sliders 24l and 24r are moved by means of the adjusting controlling motion of the equal-diameter-projections 74l and 74r in the direction of a corresponding arrow 25.2 towards the housing middle axis GA. 
     As soon as an edge 98&#39; of the shoulder 98 passes the edge 19 of the corresponding guide surface 18 and thereby the breech body 90 has reached its forward-most end position (with which the forward end position region 58 of the entraining groove 53 coacts) and the corresponding cartridge P is fully introduced into the loading chamber 44, the blocking sliders 24l and 24r move into a blocking position, and at the further rotation of the rollers 50l and 50r the shoulders 98l and 98r are rigidly locked in place. (In contradistinction to the rear-most end position region 62 of the entraining groove, which serves only for the reversal of motion of the breech body 90, the forward end position region 58 is provided with a larger rotational angle for the corresponding roller 50l, 50r, whereby the entraining groove 53 and the central guide control groove 56 cross the rotational axis 51 at an angle of 90 degrees). The guide elements 128l and 128r find themselves again in a vertical transverse position. During the further rotation of the rollers 50l and 50r (see FIG. 7) the firing cam 63 approaches the gliding skid 129l on the bottom surface 57 of the control guide groove 56l; the offset depression 64 in the bottom surface 57 of the guide groove 56r approaches the gliding skid 129r. When the firing cam 63 and the offset depression 64 have reached the corresponding gliding skids 129, the following operation is positively initiated: the firing cam 63 presses the gliding skid 129l away from the bottom surface 57. As a result thereof the control support member 121l makes an axial movement in the direction of the arrow f 1  and forces the control bolt 124l to make an equivalent motion, also towards the longitudinal axis 151 of the firing bolt 150. The resulting motion of the forward control surface 125l relative to the counter-surface 158 introduces via the latter into the firing bolt 150 an axial force component in the direction of the arrow F 1  whereby the counter-surface 161 moves relative to the rear control surface 126r of the control bolt 124r. Thereby there results a force component for axial movement of the control bolt 124r in the direction of the arrow f 1 , by means of which the control support member 121r with its control surface 130r can be deflected into the deflecting recess 64. The axial movement in the direction of the arrow F 1  of the firing bolt 150 permits the frusto-conical nose portion 153 to penetrate through the firing bolt opening 99 to ignitingly penetrate into a propellant charge fuse of the cartridge in the loading chamber 44. A firing then occurs. While the gliding skid 129l is in contact with the cam surface 63&#39; of the firing cam 63, the firing bolt 150 is positively maintained in its forward igniting position. By means of a sufficient angular traverse of the rotational movement the rigid locking duration can be predetermined and thereby a possible ignition delay can be taken account of and be safe-guarded against. 
     During the duration of the rigid locking all those forces which are produced on the breech body 90 by the propellant gas pressure during firing in the direction of the arrow 90.1 (FIG. 3) acting via the blocking sliders 24l and 24r on the housing 10 and thereby they are kept away from the entraining rollers 120l and 120r, the entraining surface 55.2, as well as the guide elements 128l and 128r, as well as the central control guide groove 56l and 56r. For sake of security there is, however, as has been previously mentioned, maintained in the corresponding section of the forward entraining groove end region 58 an axial distance between the entraining surfaces 54.1 and 54.2 which is larger than the exterior diameter of the entraining rollers 120, so that in this region 58 there is no mutual positive forcible engagement between rollers and grooves. Similarly, in the corresponding region the control grooves 56l and 56r have corresponding widths. The rigid locking is also, for sake of security, maintained a predetermined period of time after the cessation of the mutual contact between the cam surface 63 and the gliding skid 129l, on the one hand, and the gliding skid 129r and a surface 64&#39;, on the other hand, which means that after positively, via a control cam surface 65, the gliding skid 129r has again moved inwardly, counter to the directional arrow f 1 , and thereby the firing bolt 150 is moved rearwardly counter to the directional arrow F 1 , as well as thereby the gliding skid 129l with the corresponding elements (according to the afore-described ignition process in the reverse order) assume their corresponding starting positions (prior to the ignition process). During recoil and the development of the firing cycle the housing 10 moves in the direction of the arrow 90.1. Thereby also the gear wheel 78l moves relative to a gear wheel meshing therewith forming part of the auxiliary driving arrangement which is not mounted in the housing 10. In order to maintain during this motion the mutual driving form locking between both gear wheels, the width of the gear wheel 78l must be made sufficiently large. During the further rotation of the rollers 50l and 50r the afore-described function is repeated. 
     In comparison with the afore-described state of the art arrangement, the following advantages result from the arrangement of this invention: in view of a bilateral entraining guiding of the breech body 90, the friction contact between the entraining rollers 120 and the surfaces 54.1 and 54.2 of the entraining groove 53 as well as the friction contact between the round surfaces and the therewith coacting support rails and support surfaces as well as the constructional complexity for the (simplified) straight guiding means are reduced. By arranging the path of the breech body at the level of the rotational roller axis the total height of the arrangement in the pertinent region is substantially reduced. The positive actuation of the firing bolt 150 permits it to make its mass relatively small. The holding coil spring 166 serves exclusively for fixing the firing bolt 150 in its inoperative position and thereby avoids the undesirable relative movements of the control surfaces 125l, 125r and 126l, 126r and the counter-surfaces 158 . . . 161 and furnishes with the positive control of the firing bolt 150 its penetration into the corresponding propellant charge ignition fuse exclusively in the predetermined ignition region. A reduction of the moving mass of the breech body 90 serves also for the step to separate the blocking sliders 24l and 24r from the breech body 90 and to guide them firmly in the housing. By means of the forcible controlling of the blocking sliders 24l and 24r a premature unblocking with the ensuing well-known accompanying consequences is avoided. 
     Although the invention is described and illustrated with reference to a preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such preferred embodiment but is capable of numerous modification within the scope of the appended claims.