Not Applicable.
Not Applicable.
1. Field of the Invention
The present invention relates to a trigger mechanism, and more particularly to a trigger mechanism for a firearm.
2. Related Art
There are a number of trigger mechanisms that have been used for firearms, including trigger mechanisms that are particularly designed for single-barrel pistols and multi-barrel pistols. In particular, there are double-action trigger mechanisms that have been designed for Derringer-type pistols. Additionally, there are existing trigger mechanisms which can maintain a constant pressure throughout a trigger pull and can allow for an adjustment of the pressure which is required for the trigger pull, i.e, the trigger pull weight. However, none of these known trigger mechanisms provide an operation that is as smooth and efficient as the trigger mechanism provided in the present invention. In particular, none of these known trigger mechanisms combine the mechanical advantage of a wedge element (generally, an inclined plane) in the sear assembly that works in combination with the hammer spring to control the trigger pull weight as the hammer is forced to rotate from its seated position to its cocked position.
The present invention is for a trigger mechanism that has a hammer, a hammer spring, a disconnect rest and a sear assembly. In one embodiment, the sear assembly translates along a longitudinal axis between a rest position and a break point position and also moves in an arc around a rotational axis from the break point position to a disconnect position. The sear assembly has a hammer side that presses against and rotates a cam end of the hammer as the sear assembly moves between the rest position and the break point position and thereby rotates the striking end of the hammer around the hammer's pivot point from its seated position to its cocked position. The support side contacts a face of the disconnect rest as the sear assembly moves between the rest position and the break point position, and the support side has an edge that is located at the ledge at the break point position. The hammer spring forces the sear assembly to the disconnect position as the edge moves past the ledge.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiment(s) is merely exemplary in nature and does not limit the trigger mechanism invention, its application, or uses. The trigger mechanism 10 of the present invention is preferably used for firearms 100. As will be appreciated from the description below and corresponding drawings, the unique features and arrangements of the trigger mechanism 10 could be used for actuating and triggering devices other than firearms.
As shown in
As respectively illustrated in
The use of the trigger mechanism 10 according to the present invention is shown in
The elements of the trigger mechanism 10 according to the present invention for a firearm are shown in detail in
The rest 20 has a supporting face 42 and a sidewall 44 on either side of the ledge 40. The face 42 of the disconnect rest 20 supports the sear 14 as generally described above. The sear 14 preferably has a notch 46 that has an edge 48 and a pair of sides 50a, 50b that are in full contact with the disconnecting rest's supporting face 42 and sidewall 44 when it is in the rest position 34. As described in further detail below, when the sear assembly 14 is pushed to the break point position 36, the notch 46 is pushed to the point where the edge 48 of the notch is the only portion of the sear 14 that is being supported the face 42 of the rest right at the ledge 40. Any further force applied to the sear assembly 14 will push the edge 48 off the ledge 40 so that the sear moves past its break point position 36 and is forced to the disconnect position 38. When the sear assembly 14 returns back from its disconnect position 38 to its rest position 34, the notch 46 positions the end of the sear that is supported by the disconnect rest 20 in a set location relative to the rest.
According to the general principles of the present invention, the sear translates along a longitudinal axis 56 between the rest position 34 and the break point position 36 and then moves in an arc 58 around a rotational axis 60 from the break point position 36 to a disconnect position 38. The sear 14 has a hammer side 62 and a support side 64 opposite from the hammer side. As the sear translates along its longitudinal axis 56 between the rest position 34 and the break point position 36, the sear's hammer side 62 presses against and rotates the cam end 26 of the hammer 12 around the pivot point 22, thereby rotating the striking end 24 of the hammer 12 around the pivot point 22 from the seated position 30 to the cocked position 32. The angle (α) between the plane of the hammer side 62 and the plane of support side 64 forms a wedge 66 which, along with the spring constant (kh) of the hammer spring 18, and to a lesser degree the spring constant (kt) of the trigger return spring 52, defines the force (Ft) that is necessary to pull the trigger.
The wedge 66 can have one or more curved sides as shown in
The wedge 66 serves as an inclined plane which provides a mechanical advantage within the sear assembly 14, and it works in combination with the hammer spring 18 to control the trigger pull weight as the hammer 12 is forced to rotate from its seated position 30 to its cocked position 32. As shown in
The sear assembly 14 is preferably formed by a block assembly 74 that is slidingly arranged on a guide rod 76. As particularly illustrated in
When providing support to the sear assembly 14, the disconnect block 80 is positioned on the supporting face 42 of the disconnect rest 20. The wedge block 78 includes a ramp surface 90 that is arranged the wedge angle (α) which is an acute angle relative to a guide plane that is produced by the longitudinal and rotational axes 56, 60 of the sear's guide rod 76. The ramp surface 90 is the hammer side 62 of the sear that presses against and rotates the cam end 26 of the hammer 12, thereby cocking the hammer 12. The wedge block 78 also has a contact region that engages a side of the disconnect block 80 as the hammer 12 reaches the cocked position 32 and preferably includes a cocked hammer surface 92 that is adjacent to the ramp surface 90 and is arranged substantially parallel to the guide plane. In the preferred arrangement, there is no further rotation of the hammer 12 as the hammer cam translates along the cocked hammer surface 92 to the break point of the trigger mechanism 10.
The disconnect block 80 has a base surface 94 that contacts the supporting face 42 of the disconnect rest 20 and supports the guide rod 76 as the wedge block 78 is pushed by the trigger pull 16 from its rest position 34 to the break point position 36. In the preferred arrangement, the disconnect block 80 remains stationary while the wedge block 78 moves from the rest position 34 to the point where the wedge block engages the disconnect block. As particularly shown in
As described above, one side 50a of the notch 46 can serve as the base surface 94 that engages the disconnect rest 20, and the length of this side defines the distance in which the wedge block 78 pushes the disconnect block 80, i.e., the distance from the other side 50b of the notch to the edge 48 of the disconnect block 80. This distance can be coextensive with the engagement of the blocks and the trigger mechanism's break point and can be calibrated to ensure the engagement of the blocks coincides with the cocked hammer transition point. Also, the disconnect block 80 may have a slightly curved face that helps to position the disconnect block 80 as it is pushed past the ledge 40 and is forced into the disconnect position 38.
The hammer 12 is pivotally supported by the frame, preferably by a pair of pivot bearings 72 on opposite sides of the hammer's pivot point 22 that attach to the frame's opposing side walls. In the preferred embodiment, the cam end 26 of the hammer 12 includes a roller bearing 68 that contacts the hammer side 62 of the sear 14. As the wedge block 78 slides on the guide bar, the roller bearing 68 allows the hammer's cam end 26 to smoothly roll along the ramp surface 90 and the cocked hammer surface 92.
At the trigger break point (Tb) of the trigger mechanism 10, as particularly shown in
The arrangement of the sear assembly 14 components provides an efficient way to cock and release the hammer 12 followed by a quick return of the components into their rest position 34a as the trigger pull returns to its ready position 34b. It will be appreciated that changes could be made to the arrangement of the sear assembly 14 components according to the overall teaching of the present invention. For example, alternative embodiments of the trigger mechanism 10 with different arrangements of the sear assembly 14 may combine the disconnect block 80 with the wedge block 78 into a single disconnect wedge block 88, such as shown in
In these alternative embodiments, the return of the block arrangements may not be as efficient as in the preferred embodiment described above. These alternative arrangements may require an additional locking rotational element 122 in the block. The locking element would prevent the block from rotating as it slides on the guide rod 76 from the rest position 34 to the break point position 36 but would allow the block to rotate after it passes the break point and while it slides back on the guide rod 76 back to the rest position 34. As evident from the alternative arrangements, the disconnect wedge block 88 can have the ramp surface 90a on the hammer side 62 of the sear assembly 14 as shown in
The embodiments were chosen and described to best explain the principles of the invention and its practical application to persons who are skilled in the art. As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.
This application claims priority from U.S. Provisional Patent Application Ser. No. 61/552,499 filed on Oct. 28, 2011 which is hereby incorporated by reference.
Number | Date | Country | |
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61552499 | Oct 2011 | US |