How the Rhino works, part V: double action lockwork.
Wednesday, November 10, 2010 Filed in: Gunsmithing, Revolvers
As I mentioned last time, the Rhino's double action is a little more conventional - but not a whole lot!
First, we need to take a look at the left side of the hammer. It sits against the inside of the frame, and without seeing it you won't be able to grasp what's happening.
The 'hammer sear' is referred to by other makers as a 'double action strut'. In most revolvers a sear protrusion on the trigger sits under this piece, and when the trigger is pulled that protrusion lifts the strut upward, which rotates the hammer back. At some point the trigger extension slips out from under the strut, and the hammer falls. When the trigger is released, the strut (which is spring loaded) allows the trigger protrusion to slip back under the strut. The Rhino’s hammer sear does serves the same task in the same way.
(One thing about the Rhino’s hammer sear I found a little concerning: every other revolver manufacturer makes this part significantly larger and thicker, as well as orienting it to the sear extension at a nearly vertical angle of incidence. In the Rhino the part is smaller, thinner, and the force applied to it puts significant upward strain on the part’s bend. Given the generally good construction and material choice in the rest of the gun I suspect it’s not going to be a problem, but it does give one pause when considering what it’s asked to do!)
Anyhow, back to the action...
The operation on the Rhino is similar to what I’ve described, except the extension isn't on the trigger. Just as in single action, the trigger connects to the interlink lever via the connecting rod and the interlink lever is doing the actual work. Other than that, the operation is fairly close to what we're used to.
(I've removed the mainspring and some of the Rhino's parts so that you can see this a little more clearly.)
With the trigger partway pulled, you can see that the hammer is being pushed back. In the red circle (yeah, I know - it’s a poor excuse for a circle) you can see the extension of the interlink lever reaching back behind the hammer to engage the hammer sear. The hammer spring lever, which is usually under tension from the mainspring, wants to rotate counter-clockwise; a pin with a roller bearing rides in the wide slot milled in the hammer (previous picture), which gives the hammer it desire for forward movement. As the hammer is pushed back by the interlink lever, it rotates the hammer spring lever clockwise, against the mainspring tension.
The hammer is now back as far as it is going in double action, and is about to slip off the protrusion on the interlink lever.
The hammer starts to fall.....
...and hits the firing pin, igniting the round. The trigger is now ready to reset; where does it get the spring power to do so? We'll look at that next time, along with the hand - the two are linked together, and I can't talk about one without going into detail about the other!
-=[ Grant ]=-