A Method of Cutting Glass Tubes, and Apparatus employed therein.
Year: 1890

page_text: Date of Application, 11th Aug., 1890
Complete Specification Left, 20th Nov., 1890-Accepted, 20th Dec., 1890
PROVISIONAL SPECIFICATION.
A Method of Cutting Glass Tubes, and Apparatus employed therein.
I, HEINRICH BECKER, of Barmen, Rhenish Prussia, Germany, Glass Cutter, do
hereby declare the nature of this invention to be as follows:-
:-
My method of cutting glass tubes, especially thick tubes for miners' safety lamps
or any sort of hollow glass ware, gauge glasses for instance, consists in making a
little groove into the cylinder to be cut by means of an iron disc rotating at a
considerable speed, say 300 to 500 revolutions per minute and having its circumference
sharpened like a knife's edge.
Against this disc the glass tube to be cut is pressed and at the same time it is
turned round in the same direction as the disc at a slow speed.
After this has been done and the tube has been provided with as many grooves as
cuts are to be made, a sharp pointed flame like the flame of a blow pipe, or a current
of electricity is directed against or round the grooves, when the tube will break
quite at right angle to the glass in an absolutely smooth section leaving no
irregularities whatever, ready for use and requiring no polishing hereafter.
Dated this 2nd day of August 1890.
KARL I. MAYER,
Agent for H. Becker.
COMPLETE SPECIFICATION.
A Method of Cutting Glass Tubes, and Apparatus employed therein.
I, HEINRICH BECKER, of Barmen, Rhenish Prussia, Germany, Glass Cutter do
hereby declare the nature of this invention and in what manner the same is to
be perforined, to be particularly described and ascertained in and by the following
statement :-
My invention relates to a new method of cutting glass tubes, especially such
tubes which are made of thick glass, but it is of course applicable for any sort and
size of glass tubes and the object of it is to cut the glass in such a manner that the
edges be perfectly smooth and the cut surface shall be at right angle to the "flesh"
of the glass so that no grinding and polishing will be required afterwards and that
the short cylindrical pieces or small cylinders so cut off from a long tube shall be
then ready for use.
In order to attain this object I proceed in the manner described hereafter by
using the apparatus specially designed for the purpose and shown in the annexed
drawing, in which
Figure 1 is a front elevation of the cutting apparatus:
Figure 2 is a side view of the same;
Figure 3 is a plan;
Figure 4 is a longitudinal section;
Figure 5 shows the multiple blow pipes for splitting the tube after the cut.
Figure 6 is a cross section of Fig. 5.
Figure 7 is a plan of Fig. 5.
The manner of proceeding in order to obtain a clean and even surface where the
glass tube is divided or separated from the other part is to cut at first a little
into the circumference of the tube. This must be done so that the tube is held
groove
'מ

page_text: against a rotating disk having a circumferential speed of about 1000 feet per minute;
at the same time the tube is turned slowly round by hand in the same direction as
the disk.
This is important. For if the tube were to be turned in the other direction the
edges of the groove will be burnt black, whereas when done as here specified a clean
transparent edge is attained.
The disk is best made of soft wrought iron of uniform hardness and texture, the
edge of the same being sharpened like a chisel or a knife.
After the grooves have been cut as described a sharp pointed very hot flame of a
blow pipe is directed against the tube into the grooves, whereby the tube is again
turned slowly round.
This causes a rapid heating of it just in the groove and therefore a quick
expansion of the glass to the left and right of it and in consequence of it the sudden
and clean splitting of the material as desired.
The splitting may be supported by letting just a drop of cold water into the
groove this however is not necessary when the heating has been sufficiently and
suddenly enough.
For carrying out the process described I use the apparatus shown in the drawing.
It consists of a table A upon which is mounted a spindle B carried in brackets C
and being provided at one end with the cone sheaves D for varying the number of
revolutions of the shaft B. To the latter is keyed the cutting disk E.
In front of the shaft B or the disk E respectively, I arrange the tube carriers F;
these are angle shaped supports, cut out half round so that the tube can be placed
into them they are mounted upon the double slide picces G G and H H and can
be adjusted in an axial and radial direction with regard to the disk in order to be
suitable for tubes of large and small diameter. At the bottom of the slide piece H
I fix at the front or left side of the same the finger or feeler I; this has for its
object to bear against the division pieces K which are placed on the table A at the
left side of the slide piece H. The feeler 1 bearing against these pieces receives a
firm position for the tube carrier when the cuts are being made. When a circular
groove has been cut the last division piece, that is the one nearest to I, is taken out
and the slide H together with the tube is shifted to the left until the feeler touches
the next division piece.
By this means the grooves in the glass tube are all cut at equal distances or at
distances prescribed by the length of the pieces H.
'
All the grooves being cut, I put the tube into the bell shaped head L of a slowly
rotating spindle M in front of a table N upon which are arranged the multiple
(Bunsen) burners 00, which by means of india rubber pipes P are connected to a
gas main R. Instead of pure gas I use by preference a mixture of gas and air, the
air being blown into the gas main at a constant uniform pressure by means of a
blowing arrangement of any suitable design. Instead of the gas flame a spirit
lamp may be used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
(1) The manner of cutting and separating glass tubes in parts having absolutely
smooth cutting surfaces requiring no grinding or polishing, consisting in that, that
the tube to be cut is first provided with little circular grooves in being pressed
against a rotating iron disk while it is turned at the same time slowly in the same
direction as the disk, a pointed flame being then directed into the grooves, whereby
the tube is again turned slowly round.
(2) The cutting apparatus necessary for carrying out the process and consisting
of a rotary disk E mounted in bearings C upon a table A in combination with a
double slide G H carrying the tube and being provided with a feeler I bearing
against the distance pieces K upon the table A.

page_text: (3) The spindle M having a bell clamp L in combination with the multiple blow
pipe arrangement O P R, the whole as set forth and for the purpose specified.
Dated this 5th day of November 1890.