The Henzi & Pfaff caliber 602 is a very simple constructed
pallet lever movement with 17 bearing jewels, which shows
some interesting details though.
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!
inside view
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.
Detail: Center second mechanism
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.
main plate
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.
dial side view
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.
Technical data
Manufacturer
HPP
Caliber
602
Number of jewels
17
Escapement
Anchor with pallets
Balance
Nickel
Shock protection(s)
Hercules (Henzi & Pfaff)
Balance cock direction
counterclockwise
Hairspring stud
fixed
Regulator type
Hairspring key
Movement construction
Fork Escapement wheel, Fourth wheel, Third wheel, Mainspring barrel Center second pinion
Construction type
pillar construction
Bridge shape
full plate including esc.wheel, 3 gears
Winding mechanism
yoke
Setting lever spring
0 holes
Features
SCI
Functions
Hour, minute, second
Beats per hour
18000
Size
101/2''' (measured: 23,15 mm)
Image in Flume Werksucher
1957 34
Factsheet
Test Results
The specimen shown here came dirty and gummed to the lab. It was
disassembled, cleaned and olied.
The missing coupling wheel and the broken axle of the center second wheel
could not be replaced due to missing spare parts, but that made no differences
fot the lab tests. Nevertheless, you can see, that several people took hands
on this movement in the past, and not all were lucky.
Timegrapher Protocol
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.
