ratcheting mechanism on Spanish Navajas

A. G. Maisey · 29th June 2017, 05:54 AM

With my most humble apologies Chris, I beg to disagree that the role of notch and latch is to prevent accidental closure of the blade.

The role of the notch and latch is to lock the blade into position.

However, if that positive lock is not effectively made when the blade is initially opened, what occurs is accidental closure. Similarly, if the latch is accidentally or intentionally knocked the notch becomes disengaged and again we have accidental closure.

The mechanical function of any ratchet system is to permit incremental opening or closing of a loaded body. The blade of the navaja is loaded by virtue of its weight, it relies totally on the notch and latch to keep it in place. Failure of proper engagement of the notch into the latch by whatever cause will free the blade and cause damage to the hand of the user. Use of a ratchet system that will permit an incremental closure will provide a degree of protection to the user.

Risk management Chris. Just that. People have always managed risk, and this is the way they managed the risk of a loosely swinging blade in an unlocked navaja.

This entire question is actually an engineering question. I don't see it as a cultural question, or a question connected with the inherent categorisation of collecting, but rather the type of question that could be put to a design engineer , even today.

As has already been said:- "--- the ratchet may form a kind of a backup in case the back-spring for some reason disengages from the blade notch.---".

I've said exactly the same thing but in different words. In fact, my initial five word opinion is in agreement with the previous comment.

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29th June 2017, 05:54 AM	#17
A. G. Maisey Member Join Date: May 2006 Posts: 7,015	With my most humble apologies Chris, I beg to disagree that the role of notch and latch is to prevent accidental closure of the blade. The role of the notch and latch is to lock the blade into position. However, if that positive lock is not effectively made when the blade is initially opened, what occurs is accidental closure. Similarly, if the latch is accidentally or intentionally knocked the notch becomes disengaged and again we have accidental closure. The mechanical function of any ratchet system is to permit incremental opening or closing of a loaded body. The blade of the navaja is loaded by virtue of its weight, it relies totally on the notch and latch to keep it in place. Failure of proper engagement of the notch into the latch by whatever cause will free the blade and cause damage to the hand of the user. Use of a ratchet system that will permit an incremental closure will provide a degree of protection to the user. Risk management Chris. Just that. People have always managed risk, and this is the way they managed the risk of a loosely swinging blade in an unlocked navaja. This entire question is actually an engineering question. I don't see it as a cultural question, or a question connected with the inherent categorisation of collecting, but rather the type of question that could be put to a design engineer , even today. As has already been said:- "--- the ratchet may form a kind of a backup in case the back-spring for some reason disengages from the blade notch.---". I've said exactly the same thing but in different words. In fact, my initial five word opinion is in agreement with the previous comment.