US2703943A

US2703943A - Safety-means for the half-cock notch of exposed hammer firearms

Info

Publication number: US2703943A
Application number: US222986A
Authority: US
Inventors: William C Roemer
Original assignee: Olin Corp
Current assignee: Olin Corp
Priority date: 1951-04-26
Filing date: 1951-04-26
Publication date: 1955-03-15
Anticipated expiration: 1972-03-15

Description

SAFETY-MEANS FOR THE HALF-COCK NOTCH OF EXPOSED HAMMER FIREARMS Filed Aprll 26, 1951 United States Patent SAFETY-MEANS FOR THE HALF-COCK NOTCH OF EXPOSED HAMMER FIREARMS William C. Roemer, New Haven, Conn., assignor to Olin Matliieson Chemical Corporation, a corporation of The present invention relates in general to firearms of the exposed hammer type and more particularly to.

improvements in the fire-control mechanisms for insuring against unintentional discharge of the firearms.

An object of the invention is to provide an exposed hammer firearm having superior fire-control mechanism including a scar, and a half-cock notch in the hammer to prevent inadvertent discharge of the firearm.

A further object of the invention is to provide an exposed hammer firearm having a superior scar and hammer which are durable and dependable, and which may be selectively operated to hold the hammer in both its full-cock and half-cock positions.

A still further object of the invention is to provide a firearm of the type described with a sear and a hammer having a half-cock notch, the sear and the half-cock notch of the hammer being arranged to mutually coact and thereby to positively control inter-engagement of the sear with the half-cock notch.

A still further object of the invention is to provide a firearm of the class described having a half-cock notch and scar, and safety-means associated therewith to insure positive control of the sear with respect to the half-cock notch of the exposed hammer as said sear and hammer are brought into abutting engagement in moving the hammer from its full-cock position to its half-cock positron.

Other objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. l is a side elevation partly in section of the triggerplate and. fire-control mechanism of an exposed hammer type of firearm including the safety-means of this inventron;

Fig. 2 is an enlarged broken front elevation of the giggeir-plate, fire-control mechanism and safety-means of Fig. 3 is an enlarged fragmentary side elevation of the exposed hammer and sear of the fire-control mechanism and safety-means shown in Fig. 1;

Fig. 4 is a series of enlarged side elevations of the exposed hammer and sear of Fig. 3 illustrating the action of the safety-means for positively camming the sear off of the lip of the half-cock notch of the hammer to prevent abutting engagement therewith as the hammer is lowcred into its half-cock position;

Fig. 5 is a broken perspective view of the hammer showing the half-cock notch and the improved safetymeans thereof for preventing abutting engagement of the lip of the half-cock notch with the sear; and

Fig. 6 is a perspective view of the sear showing the safety-means thereof.

Heretoforc, firearms of the type to which the present invention applies, have been characterized by an exposed hammer having a half-cock notch, the outer wall of which has constituted an outwardly-flaring or beveled surface to facilitate entry of the sear into the half-cock notch when lowering the exposed hammer into its halfcocl: position. It has been discovered that this construction has been the cause of many unforeseen accidents with firearms of this type and for two plausible reasons, first, because of the outwardly-beveled side wall of the half-cock notch, it has been possible to pull off the hammer from its half-cock position, that is to say, to effect disengagement of the sear from the halfcock notch of the hammer by pulling on the trigger; and secondly, in the normal operation of lowerlng the exposed hammer from its full-cock to its half-cock position, the shooter sometimes fails to release the trigger,-

in which event the sear is not free to enter the halfcock notch of the hammer but rather may be engaged in endwise abutting relationship with the lip of the halfcock notch, and while the hammer may appear to be in its customary half-cock position, this abutting relationship of the sear with the lip of the half-cock notch is non-positive and accordingly extremely dangerous since any slight pull or jar will cause the scar to release the hammer and thus fire the gun.

The present invention relates to superior safety-means for the half-cock notch and sear of an exposed hammer type of firearm designed to overcome the aforementioned disadvantages inherent in the scar and half-cock notches of exposed hammer firearms heretofore in use. Referring to the drawings, Fig. 1 shows a hammer 10 having a firing-pin-engaging nose-portion .11 and a hubportion 12, the latter portion of the hammer being provided with a transverse aperture through which projects a pivot pin 13'which supports the hammer 10 for pivotal movement in a substantially vertical plane between the upstanding ears 14-14 of a trigger-plate 15 which serves to mount the hammer and hammer-control elements, hereinafter referred to as the fire-control means, in the firearm. The aforesaid hub-portion 12 of the hammer is provided with a rearwardly-extending nose having a transverse aperture therein in which is engaged a pin 16 for pivotally securing one end of a link 17 to the hammer, the opposite end of the link 17 being provided with a transversely-extending pin 18 which is adapted to engage in a hook at the forward end of the hammer-spring 19. The rear end of the latter is secured by fastening-means 20 to the aforesaid trigger-plate 15. The latter is provided with a vertical aperture immediately below the hammer for accommodating the trigger 21 which is pivotally supported by a transverse pivot pin 22 in the trigger-plate 15, the pin 22 serving also to support a scar 23 arranged to be actuated by the pivotal movement of the trigger in a manner well known in the art. A combined scar and trigger-spring 24 is secured at its rear end as at 25 to the trigger-plate and bears at its forward end against a rearwardly-projecting tongue 26 of the sear 23.

Referring more especially to Figs. 3, t and 5, the hub portion 12 of the hammer is provided on its bottom face 27 with a full-cock notch 28 which extends transversely across the bottom face 27 of the hammer as indicated in Figs. 3 and 5, and is substantially U-shaped in cross-section, as shown especially well in Figs. 3 and the side walls of the notch being substantially parallel and extending in a generally-radial direction with respect to the axis of the hammer. Immediately forwardly of the full-cock notch 28 of the hammer is the half-cock notch 29 which intersects the lower face 27 of the hammer and extends transversely thereacross in the manner shown in Fig. 2, the half-cock notch 29 being also substantially U-shaped in cross section but with its

respective side walls

30 and 31 respectively making angles of substantially 45 with respect to the side walls of the full-cock notch. The inner wall 30 is a substan' tially flat surface, while the outer wall 31 of the halfcock notch is substantially flat and slopes outwardly slightly relative to its inner wall. In the present embodiment of the invention, the degree of slope of the wall 31 is substantially 5. The half-cock notch 29 forms a lip 32 on the under surface of the hub-portion 12 of the hammer, which lip extends the full width thereof and has a substantially-flat beveled edge 33 which slopes outwardly and upwardly relative to the outer side wall 31 of the half-cock notch 29. By way of example, the slope of the substantially-beveled edge 33 of the lip 32 is substantially 30 relative to the end wall of the half-cock notch 29. Formed at one end of the lip 32 of the half-cock notch is an integral downwardlyprojecting spur 34 which constitutes an element of the safety-means of the sear and half-cock notch, the spur 34 being, in effect, in projection of the lip 32 and having a beveled edge 35 which is substantially parallel to the beveled edge 33 of the aforesaid lip 32.

The sear of the fire-control mechanism is shown especially well in Figs. 3, 4 and 6 and comprise a noseportion indicated generally at 36, the inner surface 37 of which constitutes a concave surface of revolution having a relatively-large radius as indicated in Fig. 4. In furtherance of this end, the front or outer face of the forward extremity of the nose-portion 36 of the-sear is formed with a clearance-cut 38 extending thereacross, whereby the forward extremity of the sear constitutes, in effect, a relatively-thin lip 39 of slightly less thickness than the width of the half-cock notch 29 of the hammer. The upstanding face 40 of the lip 39 is a substantially-flat surface extending in substantially the same direction as the inner curved surface 37 of the time portion of the sear and makes an acute angle with the outer surface of the sear-nose 36. The forward edge or tip 41 of the sear-lip 39 constitutes a substantiallyfiat beveled surface which slopes outwardly and downwardly with respect to the inner surface 37 of the searlip, the slope of the beveled edge 41 of the sear-lip being such that when the latter is engaged in the fullcock notch 28 of the hammer, the edge 41 of the searlip will engage substantially flatly against the forward wall 29:: of the full-cock notch thereby insuring positive engagement and smooth operation. A second element of the safety means of the sear and half-cock notch is a notch 42 which is formed in the beveled edge 41 of the sear-lip and at one end thereof and substantially opposite the spur 34 of the hammer, the notch 42 having a substantially-flat beveled surface 43 below the plane of the beveled edge 41 of the sear-lip and sloping generally in a direction opposite thereto. In the embodiment of the invention shown herein, the slope of the flat beveled surface 43 of the sear-notch 42 is substantially 35 relative to the base 44 of the searnose 36.

Assuming that the fire-control mechanism is assembled on the trigger-plate as shown in Fig. 1, the operation of the safety-means of the sear and half-cock notch is as follows. When the hammer is pulled back manually into its full-cock position, as indicated by the broken lines in Fig. 1, the lip 39 of the sear will engage in the full-cock notch 28 of the hammer to hold the latter in' its full-cock position in a manner characteristic of exposed hammer type of firearms. In this condition, the end surface 41 of sear-nose 36 abuts on surface 28a of the sear-notch 28. The pressure of the hammer spring thus is exerted substantially perpendicular to the common plane of these surfaces and they may be slid relative to each other simply by overcoming the frictional engagement between them. This of course is what occurs when the trigger is pulled to fire the gun.

Should it be decided, after withdrawing the hammer to its full-cocked position, not to fire the gun but to lower the hammer into its half-cock position, the hammer is engaged and held back manually to prevent it from swinging forwardly when released by the scar, and the trigger is pulled to release the sear from the full-cock notch of the hammer, whereupon the hammer is eased forwardly about its pivot pin 13 to bring its half-cock notch 29 into position for engagement with the nose of the sear. Let it be assumed, first, that the trigger has been released, as is proper, to permit the sear to automatically engage in the half-cock notch of the hammer. In this event, the force of the sear-spring 24, acting on the rearwardly-extending tongue 26 of the sear, will bias the lip of the sear so that the latter will engage against the inner wall 30 of the half-cock notch, as the hammer is being lowered into its half-cock notch position, and hence move up into the half-cock notch to engage its lip 39 fully within the half-cock notch, in the manner shown in Figs. 1 and 3. In this position the end surface 41 of scar-nose 36 rests squarely against the upper end 29a of half-cock notch 29, and outer surface 40 of the lip 39 of the sear will abut against the side wall 31 of the lip 32 of the half-cock notch if any pressure is applied to the sear causing it to rotate about its pivot in a direction to disengage it from the halfcock notch. Consequently, with the sear so engaged in the half-cock notch, the hammer is securely held in its half-cock position, and inasmuch as the outer surface 40 of the lip 39 of the sear is flared outwardly only substantially 5 relative to the inner side wall 31 of the lip 32 of the half-cock notch, even excessive trigger pull will not serve to cam the lip 39 of the sear out of the half-cock notch. Hence, inadvertent release of the hammer from its half-cock position is prevented.

If it is now assumed that the trigger is held back as the hammer is being lowered into its halfcock position, the sear 23 will thus be restrained from swinging inwardly for engagement of its lip 39 in the half-cock notch of the hammer. The position of the sear with respect to the half-cock notch of the hammer is as 1nd1- cated in the left-hand view of Fig. 4, the beveled edge or tip 41 of the lip-portion 39 of the sear being substantially opposite the beveled edge 33 of the lip 32 of the half-cock notch 29 of the hammer. As the hammer swings forwardly, the aforesaid edge 33 of the halfcock notch lip 32 moves downwardly toward the flat beveled edge 41 of the sear-lip 39. However, by making the spur 34 slightly longer than the depth of the sear-notch 42, the

beveled edges

33 and 41 of the hammer-lip and sear-lip respectively are kept apart by engagement of the beveled edge 35 of the hammer-spur 34 with the beveled surface 43 of the notch in the lip 39 of the sear in the manner shown in the center view of Fig. 4. Further, the slope of the respective beveled edges or cam-surfaces of the hammer-spur and searnotch is such that the sear is camnied outwardly or in a clockwise direction as seen in the right-hand view of Fig. 4, whereby the lip of the seat is positively moved out of engagement with the lip of the half-cock notch to preclude any possibility of these two surfaces becoming engaged in endwise or non-positive abutting relationship. With the movement of the sear outwardly past the lip of the half-cock notch, the hammer will continue to swing forwardly and if permitted, will come to rest against the firing-pin. The camming action of the beveled edge of the hammer-spur and the beveled surface of the sear-notch thus positively prevents maintenance of abutting engagement of these surfaces and hence the sear cannot hold the hammer in an unsafe, nonpositive half-cocked position. Upon releasing the trigger, the sear will then be biased by the force of. its spring 24 to swing in a counter-clockwise direction and, consequently, after the hammer has again been pulled back into its half-cock position, the sear will be free to engage in the half-cock notch of the hammer in the manner hereinabove described, to positively hold the hammer in its half-cock position. As thus positioned the notch and sear present mutuallyinterlocking overlapping

lip portions

32, 39, respectively, whose abutting faces 31, 40, are disposed substantially normal to the direction of movement induced by actuation of the trigger.

From the foregoing description, it will be clear that provision of the spur on the lip of the half-cock notch of the hammer and the notch in the lip of the sear constitute safety-means of economical, durable and dependable construction for positively preventing the lip of the half-cock notch of the hammer from being hung up on the sear-nose. Although the specific angles of the beveled surfaces of the hammer-spur and sear-notch have been found to be highly successful in producing the desired interaction between the hammer-spur and the sear, it Is within the purview of the invention to include obvious modifications of these specific angles, and to modify the safety-means by reversing the arrangement of the hammer-spur and sear-notch.

It will be seen from the foregoing that the sear-nose surface 41 is never permitted to contact a sharp edge as might occur were it not for the provision of the spur 34 on the half-cock notch 29. Surface 41 is thus positively prevented from becoming marred"or otherwise scarred. Since the frictional engagement of the sear-nose surface 41 and surface 28a of the sear-notch 28 determines to a very material degree the amount of trigger pull necessary to discharge a gun, marring of either of these surfaces would immediately affect adversely the trigger feel, rendering the same not only different from what it had previously been but constantly changing thereafter as the severity of the mar was lessened by wear. Such change in trigger feel is highly undesirable, particularly in sporting guns to which the present invention is especially applicable, since such change can affect the users marksmanship very materially. It is an important feature of the construction here disclosed therefore that the surfaces which determine the firing action, or trigger feel, of the gun are not employed for auxiliary purposes. There are, in fact, three separate sets of surfaces, for performing the various functions, each set comprising a surface on the hammer hub and a cooperating surface on the sear-nose. The function of surface 41 of the searnose and wall 28:: of full-cock notch 28 in the full-cock position have already been discussed. Surface 40 on the outer face of sear-nose 36 coacts with wall 31 of lip 32 of the half-cock notch to prevent disengagement of the sear-nose from the notch; and surfaces 35 and 43 of the notch-spur and sear-nose, respectively, cause displacement of the sear to prevent non-positive positioning thereof with respect to the half-cock notch.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. In a firearm, including in combination: a hammer movable to a full-cock position and half-cock position; fire-control means for selectively holding said hammer in its full-cock position and its half-cock position, said fire-control means including a half-cock sear-notch in said hammer, said half-cock sear-notch having a lip provided with an outwardly-and-upwardly-beveled edge; a scar arranged to engage in said half-cock sear-notch, said sear having a lip provided with an outwardlyanddownwardly-beveled edge; and safety-means to positively control the movement of said sear relative to the halfcock sear-notch of said hammer, said safety-means comprising a bevel-edged spur projecting below the beveled edge of said hammer-lip and a bevel-edged notch in the lip of said sear, the bevel-edged spur and bevel-edged notch being arranged substantially opposite each other and adapted when moved into abutting engagement by the movement of said hammer from its full-cock position to its half-cock position to automatically displace the sear-lip out of abutting engagement with the lip of said hammer and in a direction away from its half-cock searnotch.

2. In a firearm, including in combination: a hammer movable to a full-cock position from which said fire-arm may be fired and to a half-cock position from WhlCh it may not be fired by normal trigger actuation; fire-control means including a trigger, a scar actuated by said trigger, and a hammer controlled by said sear; said hammer having full-cock and half-cock notches therein for engagement by said sear; a first set of surfaces comprising one surface on said sear and another on said full-cock notch which abut when said hammer is disposed in said fullcock position, said surfaces being mutually displaceable in their common plane by normal actuation of said trigger; a second set of surfaces comprising one on said scar and another on said half-cock notch which abut when said sear is positively engaged in said half-cock notch, said surfaces being disposed substantially normal to the direction of movement induced by actuation of said trigger; and a third set of surfaces, one on said sear and another on said half-cock sear-notch, said last set when brought into abutment by movement of said hammer causing positive camming displacement of said sear with respect to said half-cock notch.

3. In a firearm, fire-control means including a hammer and a scar; said hammer having a full-cock notch and a half-cock notch for engagement by the nose of said sear, said hammer being movable to full-cock position, in which said sear-nose engages said full-cock notch and from which it can be displaced by normal trigger actuation, and to a half-cock position, in which said sear-nose is engaged in said half-cock notch and from which it can not be displaced by normal trigger actuation; safetymeans for preventing fortuitous endwise abutment of the tip end of said sear-nose on the lip of said half-cock notch whereby said sear is not positively engaged in said notch, said safety-means comprising a surface on said sear-nose spaced from the tip thereof and a cooperating surface on said notch-lip, which surfaces abut to prevent engagement between the tip of said sear-nose and said notch lip, said surfaces being angularly disposed with relation to said notch so as to cause positive displacement of the sear-nose with respect to said notch by such abutment.

4. The combination as defined in claim 3, which further includes other surfaces on said sear-nose and half cock notch, respectively, which positively prevent disengagement of said sear-nose from said notch by normal trigger actuation when said sear-nose is fully engaged in said notch.

5. The combination defined in claim 4, wherein said other surfaces comprise mutually interlocking, overlapping portions of said sear and notch when engaged in the half-cock position.

References Cited in the file of this patent UNITED STATES PATENTS 600,337 Richardson Mar. 8, 1898 695,242 Snyder Mar. 11, 1902 887,784 Fyrberg May 19, 1908 1,122,635 Pomeroy Dec. 29, 1914