IMPROVEMENTS IN THE MANUFACTURE
Year: 1883

page_text: PROVISIONAL SPECIFICATION, left by Friedrich Carl Glaser at the Office of
the Commissioners of Patents on the 2nd June 1883. A communication
made to him by Heinrich Boesner and Friedrich Baumgarten, both residing
at Augustenthal near Neuwied in the German Empire.
FRIEDRICH CARL GLASER of Berlin in the Kingdom of Prussia and Empire of
Germany, Engineer and Patent Solicitor "IMPROVEMENTS IN THE MANUFACTURE
" A com-
munication made to him by Heinrich Boesner and Friedrich Baumgarten, both
residing at Augustenthal near Neuwied in the German Empire.
OF WOOD SCREWS AND IN THE MEANS OR APPARATUS EMPLOYED THEREFOR
This invention has for its object to attain the following advantages in the
manufacture of wood screws-first, to effect the cutting of the threads in less
than half the time heretofore required for this purpose; second, to effect a
considerable saving in cost of manufacture; third, to facilitate the manufacture of
such screws on a large scale, while, at the same time these are turned out of a
better, or at least as good a quality as at present. In cutting wood screws at the
present time, the screw blank, being held in a chuck, is acted upon by a single
cutter, which is made to travel along at a speed relative to the rotation of the
screw blank corresponding with the required pitch of the screw, the cutter being
actuated by a cutter spindle and helical cam corresponding in form to the required
pitch. For cutting the thread to the required depth a wedge mechanism is
employed, operating in combination with a stepped disc or cam, which, in present
machines, has from 6 to 14, and even more steps, according to the size of the
machine, for the different kinds of screws. This stepped disc runs loose on the
main shaft and receives its motion through toothed gearing and change wheels, the
toothed wheel of the stepped disc and its pinion being in a proper proportion to the
number of steps on the disc.
According to the present invention, the cutter, instead of being formed with
only one chisel point, as at present, has two or more chisel points, of which the
following ones project rather more than the leading one, so that all of them cut
simultaneously, and the cutter, although it is only led once past the screw blank, is
thus made to cut two or more times as deep as an ordinary cutter. By this means,
the cutter only has to be led past the blank one half or a less number of times by
the helical cam than was heretofore necessary; and also, it has only to be actuated

page_text: by one half or a less number of the steps of the stepped disc and wedge arrangement
for cutting the thread to the required depth. Thus, if formerly, for instance, the
stepped disc had 12 steps of which 10 served for cutting the thread and 2 ran idle,
there is, according to the present invention, only required a disc with 6 steps, of
which 5 operate with double chisel points while one remains idle. The stepped
disc can consequently revolve twice as fast as before, which may be readily effected
by an alteration in the proportion of teeth of the change wheels. By this ineans,
at one revolution of the stepped disc, the double or multiple cutter will have cut
the same length of thread in one half the time, or less. In operating with such
double or manifold cutters, it is preferred to leave a space equal to one thread
between two successive chisel points, in order to enable the thread to be cut with
any degree of depth and sharpness, as this could not be effected so well if two
consecutive chisel points of the cutter operated in two consecutive threads. The
cutting of the thread to a greater or less depth is effected, as heretofore, by the
adjustment of the wedge mechanisın. Instead of forming the two or more chisel
points on one and the same cutter, they may be formed separate and fixed close
together in the cutter socket.
From the foregoing it will be seen that, by the use of the cutters with double or
multiple chisel edges, a corresponding reduction of the steps of the stepped disc, and
an increase of speed thereof, produced by an alteration of the change wheels, will
be effected, thus resulting in a production two or more times greater than that of
the present machines, although the speed of the chuck spindle remains the same.
By the above means, wood screws may be cut with two or more threads, instead
of with only one, as heretofore, which screws would have the advantage that they
can be screwed in and out twice as fast as the present ones. In this case, it is not
necessary to leave a space between the successive chisel points of the cutter, as
before described.