Method and Apparatus for Producing Toothed Parts of Machinery.
Year: 1896

page_text: Date of Application, 16th May, 1896-Accepted, 15th May, 1897
COMPLETE SPECIFICATION.
Method and Apparatus for Producing Toothed Parts of Machinery.
I, FRANZ LUDEWIG, of 19 Feldstrasse, Dusseldorf, in the Empire of Germany,
Engineer, 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 :-
The present invention serves for the production of toothed parts of rotary bodies
or machinery of all kinds; and consists essentially in first rough-casting the toothed
parts of machinery to be produced in such a manner that they shall show in faint
outlines the form of the teeth.
The finished form of the teeth is then produced by squeezing (pressing or rolling)
by means of dies whilst the material (forming the teeth) being thus compressed
and set up acquires an increased strength or density in these portions and by my
invention I obtain great advantages.
The accompanying drawings illustrate to a sufficient extent the process and the
apparatus employed for carrying out same.
A part V (Fig. 2) rough cast approximately into the form of the teeth is
completely finished by pressing in a female die S (Fig. 1) as indicated by dotted
lines in Fig. 2. At these portions or formed teeth the material is rendered denser
and acquires increased strength.
In pressing a toothed wheel in accordance with this invention the apparatus
illustrated in Fig. 3 may be employed.
In this figure the pressing plunger or die T carrying the toothed wheel is drawn
in two positions. The toothed wheel A rough-cast as shown at Fig. 34 is fixed
in the plunger T which is also provided at its periphery with the finished form of
the teeth. This plunger T together with the toothed wheel A is now introduced
into the female die M (Fig. 3).
This female die is provided with ribs m which correspond with the spaces
between the teeth and which corresponding with the plunger coincide exactly with
the form of the tooth spaces to be produced whilst at the top towards the place of
entry of the plunger the said ribs m are tapered to such an extent as to allow of
the rough-cast toothed wheel being casily introduced into the apparatus.
As the plunger T with the rough-cast teothed wheel A is pressed with great
pressure into the female die M the ribs m of this female die press the teeth
and the tooth spaces into their finished shape as shown at Z Fig. 3* whilst the
metal is rendered denser at these places and thereby acquires increased strength.
A toothed rim may be made in this manner and then provided with a boss by
casting same in so as to form a disc wheel as shown in Figs. 4 and 44 or a wheel
may be thus formed with spokes or arms. In this manner prejudicial initial stresses
in the toothed rim are obviated.
Teeth may be suitably formed in plain or smooth-rolled metal by means of double
female dies as shown in Figs. 5 & 6.
For this purpose the metal Z is pressed by means of a counter female die M¹
(Fig. 5) into the female die which latter imparts the finished shape to the teeth.
The said counter female die M¹ is formed with bulges or prominences k which force
the metal (requisite for forming the teeth) into the female die. For the purpose
of making a toothed ring in this way there is employed the apparatus shown in
Fig. 6. The said apparatus consists of two concentric rings M2 M3 which are
provided similarly to the female die shown in Fig. 3 with upwardly tapering ribs

page_text: corresponding to the tooth space. The ring v¹ consisting of plain or smooth-rolled
metal is pressed into the space between the said two concentric annular female
dies M and M³ so that the said ring o' is formed when it arrives in the lower part
of the apparatus with teeth complete as shown in the cross-section to Fig. 6. The
two annular female dies are suitably surrounded by a hoop B. The toothed rim
thus formed has then cast on or with it a spoke wheel or the like as shown in Fig. 7
and the toothed wheel thus formed has the advantage that as the periphery of the
wheel body is formed as a counterpart to-and so fills up-the internal cavities !
of the toothed rim the connection of these two parts together is firmly secured and
thereby any rotary movement of the one upon the other is prevented,
Toothed parts of machinery may also be made of rolled sections of wrought iron
or of articles rough-cast. This particular method of formation has for its object
to effect the impressing of shape of the teeth not over the entire width at once but
as shown in Figs. 9 and 10 in a gradual manner so that from the complex cross-
section (Fig. 11) there is formed the cross-sectional form Z (Fig. 12).
Figs. 11, 13 and 14 are respectively a cross-section, elevation, and longitudinal
section, of a rough-cast series of teeth which are to be pressed into the finished
shape by this process.
Furthermore toothed parts of machinery of this kind may also be produced by
setting up or compressing the metal in the female die. The cross-section W of
the metal is as shown in Fig. 15 formed deeper than the finished toothed rim Z
(Fig. 16) so that the metal is pressed into the tooth space.
By this means there is produced a toothed body which as shown at Z in Fig. 17
fits exactly in the female die M.
When constructing wheels of large size the pressing of the suitably rough-cast
teeth may be effected as follows:-
In a receptacle corresponding to the tool-holder of shaping or slotting machines
there is fixed a tool which contains either one steel cutter or punch for one tooth
space or several steel cutters or punches for several tooth spaces. This tool is
made as shown in Figs. 18 & 19. The advance or feed of this tool is very slow in
the direction of or on to the work whilst the up and down movement of this tool is
rapid. In this up and down movement the wedge-shaped teeth or steel tools or
punches w force the hot metal into the suitably formed recesses in the said tool so
as to produce a finished set of teeth. The work is heated by any suitable means
such as pointed flames or jets at the places indicated by a. The work table
carrying the toothed wheel to be made is moved by means of a worm and worm
wheel.
The parts of machinery pressed rolled or set up in the heated state are drawn in
the cold state through accurately formed templets or draw-rings for the purpose of
rendering the teeth uniform; whilst also the greater part of the outer skin is
rendered uniform and smooth.
The same object is effected by means of the apparatus illustrated in Fig. 20. In
this case the up and down moving tool wis replaced by a revolving roller w¹. When
it is desired to make worm wheels then instead of being in the form of rings of the
shape of the teeth in cross section the said roller is made in the spiral form of a
worm milling cutter.
Similarly to the manufacture of toothed parts of machinery screw-threaded
sleeves or sockets can also be made by this process. For this purpose the socket
or sleeve is drawn simply through draw-rings A* situated one behind the other or
it is passed through a set of rolls B* as shown in Figs. 22 & 23 whereby the
material is pressed into the inserted screw-threaded core X and is itself formed
with screw-threads see Figs. 21, 22 and 23.
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 herein-described process for the manufacture of toothed parts of

page_text: machinery consisting of rough-casting or otherwise forming the parts or blanks
with approximately formed teeth and then completing the formation of the teeth
by pressure (pressing rolling or setting up the teeth) in or with suitable dies or
apparatus.
2. Apparatus for carrying out the process claimed above combined and arranged
to act substantially in the manner and for the purposes hereinbefore described and
illustrated in the drawings hereunto annexed.
Dated this 15th day of May 1896.
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.