Improvements in Machinery or Apparatus for Milling Double Helically Toothed Bevel Wheels.
Year: 1898

page_text: Date of Application, 1st Apr., 1898-Accepted, 11th June, 1898
COMPLETE SPECIFICATION.
Improvements in Machinery or Apparatus for Milling Double
Helically Toothed Bevel Wheels.
We, EUZEBIUSZ POLANOWSKI and ADOLF JOHN, both of 3, Pusta, Lodz, Russia,
Manufacturers, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
In a prior British Patent Specification dated 26th June 1897, No. 15351 there
is described a machine for milling screw bevel wheels in which the cone disc or
bevel wheel to be treated and which rotates during the milling, is cut out along
the generating line of its bevel surface by a rectilinearly moving milling tool, the
rotary axis of which is situated in the same plane as the axis of the bevel dise
and in which plane both axes form an acute angle with each other.
In order to render this machine adapted for milling double helical bevel wheels,
that is to say bevel wheels having double helical teeth, there is added to this machine
in accordance with the present invention, a returning motion or reversing gear,
such that the bevel disc to be milled makes during the milling of each tooth firstly
a forward rotation up to the centre of the tooth to be cut, and then whilst the
milling tool continues to move in the same direction, the bevel disc moves back
again until the milling cutter has left the bevel disc. During the return of the
milling tool the bevel disc is moved in the reverse way.
In the accompanying drawings, Fig. 1 illustrates in perspective a piece of a
double helical toothed bevel wheel, whilst the other figures illustrate a form of
construction of the improved machine.
Fig. 2 is a longitudinal section on the line ab of Fig. 3. Fig. 3 is a view in
sectional elevation looking from right to left of Fig. 2. Fig. 4 is a sectional plan
of the end to be seen from the right hand of Fig. 3, partly in section. Fig. 5
shews a piece of the reversing gear or returning motion. In Figs. 2 to 4, the
parts of the machine corresponding with those described in the hereinbefore
mentioned Specification of Patent No. 15351 of the year 1897 are marked with
the same figures of reference as in the figures of the drawings accompanying the
said Patent Specification.
The motion of the shaft 23 Fig. 2, is transmitted as before by means of the bevel
wheels 24 and 25 to the shaft 26. The bevel wheel 25 is however in this case
(Fig. 4) mounted with a second bevel wheel 50 on a sleeve 51 which is capable of
moving along the shaft 26 but is also capable of rotating therewith. On imparting
rearward motion to the support 6, (Fig. 3) which carries the milling cutter, the
sleeve 51 together with the bevel wheels 25 and 50 is moved so that the bevel
wheel 50 comes into gear with the bevel wheel 24. In consequence, the shaft 26
always rotates in the same direction during the to and fro movement of the milling
tool.
The rotation of the shaft 26 (Figs. 2 and 4) is transmitted by means of the spur
wheel 27 mounted thereon, through the medium of the intermediate spur wheel 52
to the spur wheel 53; upon one end of the shaft of the latter there is keyed a star

page_text: wheel 54. The star wheel 54 gears with its teeth in a pin wheel 55 which is
mounted so as to be capable of shifting along its shaft 56 and which carries the
latter shaft 56 round with it in its rotation by means of a feather. The pin
wheel 55 is provided on each side of its row of pins along its periphery with a
groove 57, and these two grooves return into each other at two adjacent places
on the pin wheel (see Fig. 5), so that both grooves form a continuous groove with
two turning points.
In the groove 57 there engages the end of the shaft that carries the star wheel 54
in such a manner that when this enil reaches one or the other turning point of the
groove 57 the star wheel 54 which is continually rotating in the same direction
will impart a reverse rotation to the pin wheel 55. On entering one of the
turning points of the groove 57 the shaft of the star wheel 54 moves the pin
wheel 55 parallelly to its shaft 56, and in order that this shall take place uniformly,
there are arranged on an arm 58 fixed on the shaft 56, two levers 59 and 60
(Fig. 4) which are connected together and of which one engages at the periphery,
and the other at the hub of the pin wheel 55. The pin wheel 55 therefore makes
alternately one rotation in one direction and one rotation, in the other. direction.
!
The rotary motions of the pin wheel 55 are transmitted by the spur wheels 61
and 62 to a bevel wheel 63 which in turn moves the bevel wheel 64 of the shaft 29.
The shaft 29 transmits its motion in the same manner as described in Patent
Specification No. 15351 of the year 1897, by means of the change wheels 30
and 31 to the worm wheel 44 or 49 which carries the bevel disc to be cut. The
ratios of gearing of the wheels which operate the pin wheel arc so chosen that the
pin wheel during one travel of the cutting tool will rotate the bevel wheel to be
cut, first in a forward direction until the milling tool has reached approximately
the centre of the bevel surface, and will then move it back again in the manner
which is required to form the double helical teeth.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. A. machine for milling double helical bevel wheels (bevel wheels with double
helical teeth) characterized by the fact that the bevel wheel to be cut is, during the
shifting movement of the rotating milling cutter, first turned by means of a
reversing or returning motion so as to make one forward rotation up to about the
middle of the tooth to be cut, and then make a return movement whilst the milling
cutter continues to move in the same direction.
2. The arrangement and combination of parts composing our improved machine
or apparatus for milling double helically toothed bevel wheels, constructed and
acting substantially as and for the purposes described with reference to the accom-
panying drawings."