Abstract:
A break-open firearm having an improved cocking mechanism in which the hammer strut is extended to interact with the cocking rod without an intermediate energy-consuming arrangement.

Description:
BACKGROUND OF THE INVENTION 
     Numerous arrangements have been proposed for cocking the hammers of breakdown or break open firearms (U.S. Pat. Nos. 767,557; 714,193; 840,507; and 1,143,612). 
     In all prior art arrangements, one of the main factors making cocking of a break-open firearm difficult, has been excessive friction between the numerous working parts. Usually, a cocking rod operates against a portion of an an intermediate member, which in turn forces the hammer back against the force of the hammer spring. Prior art arrangements, to date, have not provided a simple and easy to operate system which allows the cocking rod to operate directly against the hammer strut, thereby substantially reducing friction and easing the cocking effort considerably. 
     SUMMARY OF THE INVENTION 
     It is therefore a general object of the present invention to provide a cocking mechanism which will overcome the above prior art shortcomings as well as other disadvantages of prior art cocking mechanisms. 
     It is the principal object of the present invention to substantially reduce the physical effort necessary to cock the hammers of break-open firearms. It is also an object of the present invention to provide a hammer and hammer strut assembly in which features of the hammer and hammer strut serve to keep said components in close mechanical relationship with each other and without fear that said hammer and hammer strut become misaligned with each other. 
     It is a further object of the present invention to reduce the number of parts necessary to accomplish the cocking of the hammers of break-open firearms. 
     Briefly, the present invention comprises a break-open mechanism in which a cocking rod is translated by a camming arrangement as the barrel-forend assembly and frame-stock assembly of the firearm are pivoted with respect to one another. The translated cocking rod acts directly on an extension of the hammer strut which projects forward of the hammer to compress the hammer spring. The hammer is pivotable to its cocked position by application of a small force exerted by the hammer strut extension as the hammer spring is beeing compressed by the cocking rod translation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial cutaway elevational view of a prior art shotgun showing a cocked hammer and hammer strut mechanism; 
     FIG. 2 is a partial cutaway elevational view of the present invention, showing a cocked hammer and hammer strut mechanism; 
     FIG. 3 is a partial elevational view of the present invention showing the hammer at rest; 
     FIG. 4 is a partial elevational view of he present invention showing the hammer fully cocked while the cocking rod is still in its rearmost position, i.e. the barrel is open. 
     FIG. 5 is a sectional view of FIG. 4 taken along line 3--3; and 
     FIG. 6 is a partial elevational view of the present invention, showing the hammer in the striking position at the instant of firing a cartridge. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In order to simply the description of the prior art and present invention firearms, only one cocking and firing mechanism will be described even though the firearms shown have two barrels and would normally require another substantially identical cocking and firing mechanism. 
     Referring now to the drawings and particularly to the prior art firearm of FIG. 1, firearm 10 includes a barrel-forend assembly 8 arranged for pivotal motion upon a frame-stock assembly 9. Barrel-forend assembly 8 includes upper barrel 12, lower barrel 14, forend 18, forend iron 16 and ejector/extractor 20 which will not be mentioned further in the description. Frame-stock assembly 9 includes frame 26, stock (not shown) top lever 30, trigger 32 and trigger guard 34 which will also not be mentioned further in the description. 
     Starting with the prior art firearm in the battery position, the cocking of hammer 36 is accomplished by pivoting barrel-forend assembly 8 about theoretical center 26b in a counterclockwise direction. The hinge means (not shown) allowing said counterclockwise rotation, will not be explained further, as it is well known to those skilled in the art. 
     As the barrel-forend assembly 8 is rotated counterclockwise, nose 22a of ejector sear 22 is forced against first end 42a of cocking rod 42 translating the latter to the right until second end 42b of cocking rod 42 contacts first cam 44a of cocking member 44. Ejector sear 22 is held rigid relative to forend iron 16 by the resistance of hammer spring 40 and rotates with barrel-forend assembly 8. The pivotal function of ejector sear 22 is used during the extraction/ejection cycle and does not pertain to the present descriptions. Cocking member 44 is thus rotated about pivot 50 in a counterclockwise direction, causing second cam 44b of cocking member 44 to be forced against nose 36c of hammer 36. The latter is now forced to rotate about pivot 48 in a clockwise direction. Hammer strut 38, whose first lobe 38a rests in first pocket 36a of hammer 36, is thus forced to the right, compressing hammer spring 40 against abutment 26a of frame 26. An aperture in abutment 26a guides hammer strut rod 38c  of hammer strut 38. The cocking cycle is completed, when sear 52, biased about pivot 54 in a clockwise direction engages sear notch 36d of hammer 36. When barrel-forend assembly 8 is rotated clockwise, back to the battery position, spring 46, which has been tensioned during the cocking cycle, forces cocking member 44 to rotate in a clockwise direction, returning it to the position which it occupied before the cocking cycle started. In so doing, first cam 44a forces cocking rod 42 to the left until it also is returned to the position it occupied before the cocking cycle started. 
     Referring now to FIGS. 2, 3, 4, 5 and 6, the firearm 10 of the present invention includes a barrel-forend assembly 8 arranged for pivotal motion upon a frame-stock assembly 9. Barrel-forend assembly 8 includes upper barrel 12, lower barrel 14, forend 18, forend iron 16 and ejector/extractor 20. Frame-stock assembly 9 includes frame 26, stock, (not shown), top lever 30, trigger 32 and trigger guard 34. 
     Starting with the battery position, the cocking of hammer 37 is accomplished by pivoting barrel-forend assembly 8 about theoretical center 26b of frame 26 in a counter clockwise direction. This action forces nose 22a of ejector sear 22 against first end 43a of cocking rod 43 and translates the latter to the right until second end 43b contacts surface 39e of hammer strut 39, forcing the latter also to the right. As barrel-forend assembly 8 continues to be rotated, hammer strut 39 compresses hammer spring 40 against abutment 26a of frame 26. An aperture in abutment 26a guides hammer strut rod 39c. Hammer strut 39 includes hammer strut extension 39 t. 
     While hammer 36 in the prior art firearm had to be rotated against the force of hammer spring 40 to be cocked, hammer 37 of the present invention has only to be &#34;nudged&#34; to the cocked position, resisting only with its mass. This is accomplished as follows: 
     Turning to FIGS. 3 and 4, just prior to the translation to the right of hammer strut 39, a small clearance gap exists between nose 39d of hammer strut 39 and cam radius 37c of hammer 37, while first and second lobes 39a and 39b respectively of hammer strut 39 are firmly seated in first and second pockets 37a and 37b respectively of hammer 37. As hammer strut 39 is forced to the right its nose 39d in hammer strut extension 39t contacts cam radius 37c of hammer 37. This motion creates a small clearance gap between first and second lobes 39a and 39b respectively of hammer strut 39 and first and second pockets 37a and 37b respectively of hammer 37 thus removing the force of hammer spring 40 completely from hammer 37. As hammer strut 39 continues to be forced to the right its nose 39d gently pushes or &#34;nudges&#34; hammer 37 in a clockwise direction through contact with cam radius 37c. Importantly, the center of cam radius 37c coincides with the center of first pocket 37a of hammer 37. As the cocking cycle continues, and hammer 37 continues to be rotated, first lobe 39a will continue to remain in first pocket 37a without applying the force of hammer spring 40 to hammer 37. When hammer 37 has been &#34;nudged&#34; to the cocked position in this manner, sear 52, biased about pivot 54 in a clockwise direction, engages sear notch 37e and thus prevents any subsequent counterclockwise rotation of hammer 37. 
     An additional feature of the above described cocking mechanism is angled mating surface 43c and 39f of cocking rod 43 and hammer strut 39 respectively. Because of the fact that hammer spring 40 exerts its force above second end 43b of cocking rod 43 and surface 39e of hammer strut 39 to the latter would tend to pivot clockwise, having as its center of rotation the intersection of the center line of hammer strut rod 39c and the left abutment surface of abutment 26a when cocking rod 43 applies a force to hammer strut 39. If this were to occur, the engagement of nose 39d of hammer strut 39 and cam radius 37c of hammer 37 would not be assured. Angled mating surfaces 43c and 39f prevent the problem by vertical engagement with one another during the cocking cycle. 
     The release of hammer 37 to fire a cartridge is prior art, with the exception of control surface 37d of hammer 37, the function of which is as follows: As barrel-forend assembly 8 is returned to the battery position, the force against surface 39e of hammer strut 39 is removed, allowing hammer spring 40 to force hammer strut 39 to the left, until first lobe 39a makes contact with first pocket 37a of hammer 37. At this point hammer 37 is subject to the full force of hammer spring 40. Also, the small clearance gap between nose 39d and cam radius 37c has been reestablished. Cocking rod return spring 47 which has been tensioned during the cocking cycle by engagement with bore 43d of cocking rod 43 now returns the latter to the position it occupied before the start of the cocking cycle, thus creating a large gap between second end 43b of cocking rod 43 and surface 39e of hammer strut 39. When hammer 37 is released by disengaging sear 52 from sear notch 37e, hammer spring 40, through engagement of first lobe 39a of hammer strut 39 in first pocket 37a of hammer 37, drives the latter in a counterclockwise direction toward firing pin 56. When hammer 37 reaches its &#34;at rest&#34; or rebound position, second lobe 39b of hammer strut 39 will seat in second pocket 37b of hammer 37 and hammer spring 40 will have taken a position of greatest expansion and least tension. 
     Theoretically, the counterclockwise rotation of hammer 37 would stop at this point because continued counterclockwise rotation of hammer 37 would require the unseating of first lobe 39a from first pocket 37a  and the compression of hammer spring 40. However, because of the inertia of the moving mass of hammer 37, this is precisely what takes place. Hammer 37 continues to rotate until it is stopped by surface 26c of frame 26 thus driving firing pin 56 toward the cartridge (FIG. 6). Now that energy stored in pivoting hammer 37 has been expended, hammer spring 40, which has been compressed slightly rotates hammer 37 in a clockwise direction through engagement of second lobe 39b of hammer strut 39 in second pocket 37b of hammer 37 until first and second lobes 39a and 39b are resting in first and second pockets 37a and 37b of hammer 37. In the above description, when hammer 37 rotates in a counterclockwise direction, from the rebound position to the striking position, surface 37d passes in close proximity, without contact, of nose 39d of hammer strut 39. As can be understood from the foregoing description, nose 39d of hammer strut 39, cam radius 37c and control surface 37d, both of hammer 37, assure that first lobe 39a of hammer strut 39 is captured in first pocket 37a of hammer 37 during the cocking cycle while releasing second lobe 39b of hammer strut 39 from second pocket 37b of hammer 37 and that second lobe 39b of hammer strut 39 is captured in second pocket 37b of hammer 37 while releasing first lobe 39a of hammer strut 39 from first pocket 37a of hammer 37 during that part of the firing cycle which takes places in a counterclockwise direction from the rebound or &#34;at rest&#34; position and that both, first and second lobes 39a and 39b respectively of hammer strut 39 are captured in both, first and second pockets 37a and 37b respectively of hammer 37 in the rebound or &#34;at rest&#34; position. 
     In a two barrel firearm with two hammers the above described arrangement exists for each hammer (FIG. 5).