Improvements in Milling Machines
Year: 1893

page_text: Date of Application, 3rd Jan., 1893-Accepted, 11th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in Milling Machines.
A communication from abroad by JOHN BECKER, of Water Street, Fitchburg,
in the State of Massachusetts, in the United States of America, Manu-
facturer.
I ALFRED GEORGE BROOKES of 55 & 56 Chancery Lane, in the County of
London, Chartered Patent Agent 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 :-
It is well known that with small cutters a very much greater variety of work can
be done than with larger cutters, yet as milling machines prior to my invention
have been constructed, it has not been practical to employ small cutters because to
operate efficiently they must be rotated at high speed, and the spindle must always
be vertical to the platen or work-support, the speed varying for the particular class
of work and the size or delicacy of the cutter.
In this stage of machine construction it is a great desideratum to run the parts
at the highest possible speed consistent with good work.
With these facts in mind
my correspondent has by experiment devised a milling machine in which the
practical speed of rotation of the spindle is far in advance of that of any other
milling machines known to me.
To do this, in addition to its usual bearings, I have provided the milling spindle
with an adjustable auxiliary bearing located in the line of the belt pull, its function
and purpose being to prevent tipping or deflection of the spindle due to the
strain of a belt kept sufficiently taut to ensure high speed, and to release the
usual bearing from much of the wear that it is commonly subjected to when
the belt strain is resisted by one half of the usual bearing.
I have also made this auxiliary bearing adjustable in a horizontal plane toward
and from the center of the main bearing and of rotation of the spindle, such
adjustment enabling the spindle to be run in its main or usual bearings with a
loose as contradistinguished to a tight fit.
One part of my invention, therefore, consists in the use in a milling machine
of a spindle having common fixed bearings for supporting it beyond the driving
pulley, a driving pulley for said spindle, and an auxiliary bearing arranged in
the line of pull on said pulley, substantially as will be described.
Also in the use with a milling machine, the spindle in which has common fixed
bearings for supporting it beyond the driving pulley, of a driving pulley, an
auxiliary bearing arranged in the line of pull on said pulley, and means to
adjust said auxiliary bearing relatively to the spindle, substantially as will be
described.
Also in the use in a milling machine having a spindle provided with common
fixed bearings for supporting it beyond the driving pulley, of a driving pulley,
a hub on the pulley, and an auxiliary bearing arranged in the line of pull of
said pulley and acting against said hub, substantially as will be described.
'
Fig. 1, in side elevation represents a sufficient portion of a vertical milling
machine with my improvements added to enable my invention to be understood, the
fig. showing a portion of the platen or work-support.
Fig. 2, is a partial view below the section line x, Fig. 1, of the auxiliary bearing
with part of the pulley broken out,
Fig. 3, is a modification to be described; and
Fig. 4, shows the auxiliary bearing in perspective.
The frame work having the quide or track A¹ at the end of its overhanging

page_text: arm; the carriage C grooved to embrace the guide or track, and adapted to be
adjusted vertically thereon; and the platen or work-support or bed B, are and may
be all as usual in milling machines, and in practice the carriage may have com-
bined with it any usual device by which to effect the vertical feeding in the ascent
and descent of the spindle, and the platen may have combined with it any devices
commonly used in milling machines for such purpose.
1
The carriage C has two boxes c', c² which constitute the main bearing for the
spindle D, shown as hollow, and as provided at the part 2 with a collar c, which,
by contact with the part of the main bearing, supports the weight of the
spindle.
The spindle will preferably have a substantial, but it may yet' be loose, fit in the
bearing parts c¹, c².
The spindle has combined cooperatively with it an auxiliary bearing a, having a
concaved face or seat, it, as shown, being provided' at one end with holes a* to fit'
over the studs a¹ on the foot a" of the auxiliary bearing stand.
The auxiliary bearing will preferably be provided with a groove for the reception'
of an oil supply shown as a wick a².
The bearing stand a¹ has, as shown, a hole a³ which is entered by a set screw a²
of smaller diameter, in order that the auxiliary bearing may be adjusted horizontally
when the set screw is loose.
I prefer, however, to combine with this auxiliary bearing, devices, as'screws' a³, a',
whereby it may be adjust positively and powerfully as may be desired, the set
screw a² being employed to confine the bearing in its adjusted position.
The belt pulley D', and the spindle, are so connected' and combined; as by a
spline or groove, as to enable the spindle to be moved vertically toward and from
the platen, but without the said pulley rising and falling with it.
The spline is shown by the letter e..
The pulley Dis chambered at oue side to receive the auxiliary bearing as
shown in Fig. 1, and to bring the said bearing' inside that part of the pulley
surrounded by the 'belt D2 so that the said 'auxiliary bearing'supports' the spindle
in the line of the belt pull.
The belt' D' is passed over the idle pulleys A², and' in'practice said belt may be
driven in any manner common to vertical milling machines.
In Figs 1 and 2; I have shown as I prefer the pulley D₁as provided with a
long hub d which enters and fits the concavity a20 of the auxiliary bearing a, the
hub being interposed between the spindle and auxiliary bearing; the hub having
a collar d² to engage a part of the auxiliary bearing to thus overcome any tendency
of the pulley rising with the spindle.
It is not, however, intended to limit this invention to the employment of the
long hub, as it may be entirely omitted, as in Fig. 3, and yet my invention would
be preserved in a construction' so modified, and in so far as tlie auxiliary bearing
is concerned' as a support' for the spindle in the line of the pull of the belt.
The use of the long hub' materially lessons the wear on the spindle.
The auxiliary bearing referred to may be so adjusted as to take substantially all
the friction due to the pull of the belt' and let the spindle run in the mâin
bearings c, c², in' such manner as to touch' or barely touch, or so as not to touch!
at all, and' consequently the bearings c', will not heat or wear, and what is of
the greatest practical importance in operation, the spindle may be kept? vertical
to the face of the platen or support B'however taut the belt' and the speed of the
spindle:
I have shown the tool-holding clutch as split at its lower end, and as having a
threaded shank 'to be'engaged by a rod f1 having a milled head, the rotation of
the rod enabling the clutch to be drawn into the lower end of the spindle when it
is desired to clamp the shank of a tool or vice-versa.
The invention herein contained' is not limited to the exact shape shown for the
auxiliary bearing.

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 [
claim is :
1. The use in a milling machine, of a spindle having common fixed bearings for
supporting it beyond the driving pulley, a driving pulley for said spindle, and an
auxiliary bearing arranged in the line of pull on said pulley, substantially as
described.
2. The use with a milling machine, the spindle of which has common fixed
bearings for supporting it beyond the driving pulley, of a driving pulley, an
auxiliary bearing arranged in the line of pull on said pulley, and means to adjust
said auxiliary bearing relatively to the spindle, substantially as described.
3. The use in a milling machine having a spindle provided with common fixed
bearings for supporting it beyond the driving pulley, of a driving pulley, a hub on
the pulley, and an auxiliary bearing arranged in the line of pull of said pulley and
acting against said hub, substantially as described.
Dated the 2nd day of January 1893.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.