HPP 602

Description

The Henzi & Pfaff caliber 602 is a very simple constructed pallet lever movement with 17 bearing jewels, which shows some interesting details though.

Video on YouTube

This movement is constructed like a Roskopf movement, although the Roskopf constructions where hardly used outside the class of pin lever movements. In terms of construction, this means, that there are only three instead of four transmission steps, since there’s no minute wheel any more. Additionally, the cannon pinion sits loosely on an axle instead of the minute wheel and is driven by the mainspring barrel on the dial side. Another characteristic of Roskopf movement is, that there’s no transmission wheel for the hour gear, since it is directly driven by a second gear of the mainspring barrel.

The advantage of this construction is besides cost-efficiency, that the mainspring barrel can have a much larger diameter, since there’s no central minute wheel. It can even overlap the center of the main plate. For power reserve and precision, this is a big advantage!

The HPP has got a rather large two leg ring balance. The hairspring is fix connected to the balance cock and can be regulated in its effective length with the hairspring key only. The balance beats with 18000 A/h (unlike the standard beating frequency of 17280 A/h of true Roskopf movements) and is located in two inhouse shock protection systems, called “Supershock HPP” or “Hercules”.

The lever is a true pallet lever.

A pretty interesting constuction, which can often be found on Roskopf movements, is the one of the indirectly driven center second: The only single-side beared center second gear is driven by the fourth wheel - directly teeth by teeth. This constriction required precisely cut gears without height differencts, but of course, it is pretty cheap and avoids jumping second hands.

On the main plate, this movement is still marked as HP 602, so it is probably an older issue of this movement.

On later versions, the click mechanism is simplified. Here, there’s a true click, which blocks the crown wheel and not the ratched wheel, but later versions just use a single click spring, directly blocking the ratched wheel.

On the dial side, you see the very simple made yoke winding system, where yoke spring and yoke are one single part. you can find this construction often on Roskopf movements, and when you compare it to e.g. a Baumgartner 34, you will notice several similarities.

In the lab

Timegrapher result

For a movement of approx. 55, which is of a simple construction, the results are astonishing well. There are no abnormalities, and the deviation window of -15 ... +15 seconds per day is more than just "good"! The slanted patterns on position "dial up" can be a sign of the broken center second hand axle, which avoids a proper centering of that wheel.

Technical data

Usage gallery

Links