IMPROVEMENTS IN WATCH MAKERS TOOLS."
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by David Louis Petitpierre at the
Office of the Commissioners of Patents on the Sth February 1882.
DAVID LOUIS PETITPIERRE of Couvet Switzerland. IMPROVEMENTS IN
WATCH MAKERS TOOLS."
The Invention consists of improvements in the watchmakers lathe the object of
which is to enable the operator to produce a better class of work and to expedite
the operation. To this end an horizontal shaft is mounted in bearings in which it
rotates. A collar is fitted onto the said shaft and prevents any end wise movement
of the shaft. A pulley or disc is secured to the end of the shaft and rotates the
same. A. face plate carrying grippers is fixed upon a stud provided with a conical
point which stud is fitted into the end of the said horizontal shaft. The pin is
formed with a longitudinal groove into which an adjustable screw fits. The said
pin is fitted with a tapped hole corresponding with the screw so that when the
latter is screwed to the pin the said face plate will be secured in position. The
disposition of the axis of the lathe is intended to permit of the ready removal of
the face plate when it is required to fix in position a fresh face plate required to
operate upon a different class of work. All the said plates are fitted with a pin
which fits the central shaft and are formed with a conical end and are provided
with a groove into which a screw penetrates and with a tapped hole corresponding
with the screw. The said face plates only having the said conical pin fitted
thereto. Caps the inside diameter of which corresponds with the size of the pillar
plate are screwed upon the plates to an extent less than the thickness of the
pillar plate. The suid caps are made all alike have two little pins on the same
diameter and at equal distances from the center, which are intended to determine
the position that the pillar plate is to assume within the caps and which fix the
point of the caliber of each moving part. Each plate is provided with a pair of
grippers. Each of the caps is placed on the plate in such a manner that the
geometrical center of the shaft exactly corresponds with one of the points of the
caliber. By making use of two bench marks the position of which is permanent
it will be sufficient to place a pillar plate already turged as to the size and thickness
and provided besides with two holes situated on any diameter but bored at a
distance from the center exactly determined into the cap of the plate which
may happen to be placed then on the lathe to make without any finding

page_text: the required place the required sinking of the mover corresponding with the
position of the cap upon the plate as well as for the setting of the stone. Thus
for instance the caliber being given the componant parts of the apparatus being a
barrel central wheel and train of wheel, balance and minute wheel. To dispose
upon the seven plates in such a manner that by placing on the table a pillar plate
turned as to the size and thickness and provided with the holes corresponding with
the pins the center of this plate (namely the axis of rotation of the lathe) may
correspond with the center of the barrel. The principal part of the Invention
consists in the use in the manufacture of watches of a number of lathe plates equal
to the number of movers which compose a caliber whether the plates are intended
to be alternately fixed to the axis of a common lathe or fixed graver in order to
finish the pillar plates of watches without being obliged to mark the caliber upon
the pillar plates. The special arrangement of mounting the hollow axis of the
lathe and shaft which permits of the ready removal of the plates. The caps
intended to determine the position of the pillar plates. The push pieces intended
to render the ready removal of the pillar plate when the work is finished. The
disposition of the support and of the screw and shoe with a view of exactly deter-
mining the depth of the sinking necessary for setting the stones into the pillar
plates or into the bridges of watches.