Improved Lathe Attachment for Milling or Outting the Teeth of Bevel Wheels.
Year: 1895

page_text: Date of Application, 27th Apr., 1895-Accepted, 27th July, 1895
COMPLETE SPECIFICATION.
Improved Lathe Attachment for Milling or Outting the Teeth of
Bevel Wheels.
I, JOHN CHALMERS MCKENZIE Clifton Villa, Mill Hill West Cowes, Isle of
Wight 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 :-
In the accompanying drawings
Fig. 1. is a vertical elevation shewing my new attachment fitted on a lathe.
Fig. 2. is a plan taken on a line through the centre line of the levers, shewing
my said attachment in position.
Like letters indicate corresponding letters throughout the drawings.
A represents a bevel wheel placed in position on the chuck of the lathe, secured
by a screwed pin, nut, and washer.
B is a bracket for supporting shafts, pulley, and bevel wheels for driving cutter,
which represents the attachment added to the rest of the lathe.
C is a steel tempered cutter with teeth cut in the same manner as those of a
inilling machine cutter, screwed with a left-hand thread on to the sleeve D, which
is driven by the shaft E with a feather D'. The sleeve D has a recess E¹ to
receive the lever J.
The shaft E is connected with the bevel wheel F, which in turn gears with the
bevel wheel G, which is connected to the shaft H.
I is a pulley attached to the shaft H and may be driven from a countershaft.
This gives a circular motion to the shaft E, and the sleeve D and therefore
gives the circular motion to the cutter C, necessary for cutting the bevel tooth.
There is a double adjustable eccentric on the shaft H for giving a vertical
motion to the cutter C, through the lever J, consisting of an eccentric H³ turned
on the shaft H, and an eccentric H2 fitted over the eccentric H³. Both these
eccentrics have the same throw, but the combined throw transmitted to the lever J,
by means of the strap H, can be reduced by shifting the eccentric H³ within the
eccentric H³, and fixing in the required position by a key in the keyways H*.
This vertical motion is for the purpose of cutting the exact bevel on the tooth
for the pitch required.
The cutter Cis at nil when it enters the cut in the wheel A. and increases in
stroke as it proceeds through the tooth until it reaches the outside of the tooth
which is the greatest stroke required.
The eccentric communicates the vertical motion to the cutter C by means of the
lever J, which has a slot in it, and slides on a block which is attached to the
bracket L.
The lever J is attached at one end to the eccentric strap H' and at the other end
to the sleeve D, and moves along bodily with the bracket B, wheels, cutter (and
the like) by means of the feed handle K, while the bracket L remains stationary
on the slide rest.
This movement changes the position of the fulcrum as the feed increases and
therefore the stroke of the cutter C which causes the cutter C to cut the teeth to
the angle and pitch required in one cut.
There is a bracket M bolted on to the sheers of the lathe, with a set pin N for
holding the dividing chuck fast in place when the wheel is in position, and enables
the cutter to cut the teeth to the pitch and angle required.

page_text: 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 1
claim is :-