IMPROVEMENTS IN CONSTRUCTION OF MILLING MACHINES
Year: 1867

page_text: LETTERS PATENT to Thomas Greenwood, of Leeds, in the County of
York, Machine Maker, for the Invention of "IMPROVEMENTS IN
CONSTRUCTION OF MILLING MACHINES."
Sealed the 22nd October 1867, and dated the 29th May 1867.
PROVISIONAL SPECIFICATION left by the said Thomas Greenwood
at the Office of the Commissioners of Patents, with his Petition, on
the 29th May 1867.
I, THOMAS GREENWOOD, of Leeds, in the County of York, Machine Maker,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE CONSTRUCTION OF MILLING MACHINES," to be as follows:-
Hitherto in the construction of machines for milling straight work, great
difficulty has been experienced in adapting such machines for work of various
sizes. To increase the range of the machine so as to make it generally useful,
and therefore applicable to small workshops, it is necessary either to provide
for the raising of the spindle which carries the milling tool, or for the sinking
of the slide that carries the work under the action of the rotary cutter. The
spindle, however, when made adjustable has hitherto had its bearing carried by
supporting screws which give great unsteadiness to the spindle, and when to

page_text: avoid this difficulty the slide has been made to rise and fall, inclined surfaces
or other contrivances have been used which limited the vertical motion of the
slide to such an extent as to disqualify the machine for general adoption.
In order, however, to avoid these objections, I form in the bed of the machine,
immediately below the spindle, vertical guides to receive a sliding block, on
which is mounted the slide for carrying the work. A screw bolt carried by
A cross piece connecting these guides at their lower ends enters a tapped hole
in the bottom of the vertical sliding block, and on being turneu will raise or
depress the block as required to any given distance within its range without
imparting any unsteadiness to the block. The work is intended to move under
the cutter transversely of the machine, and for this purpose it is made fast to
a slide which works in guides carried by a lower slide, and fitted with a
traversing screw as usual; this lower slide is capable of receiving an endway
adjustment to bring the work in line with the cutter, and for this purpose it
is mounted on horizontal guides attached to or forming part of the vertical
sliding block,
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Greenwood in the Great Seal Patent Office on
the 29th November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
GREENWOOD, of Leeds, in the County of York, Machine Maker, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of May, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Iler reign, did
for Herself, Her heirs and successors, give and grant unto me, the said Thomas
Greenwood, Her special licence that 1, the said Thomas Greenwood,
my executors, administrators, and assigns, or such others as I, the said Thomas
Greenwood, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter during
the term therein expressed, should aud lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE CONSTRUCTION
OP MILLING MACHINES," upon the condition (amongst others) that I, the
said Thomas Greenwood, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should parti-

page_text: cularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in
the Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Greenwood, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed and to the
letters and figures marked thereon (that is to say) :-
Hitherto in the construction of machines for milling straight work great
difficulty has been,experienced in adapting such machines for work of various
sizes. To increase the range of the machine so as to make it generally useful,
and therefore applicable to small workshops, it is necessary either to provide
for the raising of the spindle which carries the milling tool, or for the sinking
of the slide that carries the work under the action of the rotary cutter.
The
spindle, however, when made adjustable has hitherto had its bearing carried
by supporting screws which give great unsteadiness to the spindle, and when
to avoid this difficulty the slide has been made to rise and fall, inclined
surfaces or other contrivances have been used which limited the vertical
motion of the slide to such an extent as to disqualify the machine for general
adoption. In order, however to avoid these objections, I form in the bed of
the machine, immediately below the spindle, vertical guides to receive a sliding
block on which is mounted the slide for carrying the work, and by means of
a vertical screw, which enters a tapped hole in the bottom of the vertical
sliding block, I raise or depress the block as required to any given distance
within its range without imparting any unsteadiness to the block.
In the accompanying Drawings I have shewn my improved milling machine
in several views.
Fig. 1, Sheet I., is a side view of the machine shewing the milling tool or
cutter in place on its mandril.
Fig. 2, Sheet II., is a plan view of the same with the mandril removed and
the bracket arm which carries it broken away the better to shew the.
underlying parts.
Fig. 3, Sheet III., is a front elevation of the machine, a portion of the bed
being in section the better to shew the vertical sliding block and its connections,
and Fig. 4 is an end elevation of the portion of the bed so cut away.
In Sheet IV., Fig. 5 shews the bed of the machine in plan view, with the
sliding block only applied thereto, and Figures 6 and 7 are side and end.

page_text: views of a short standard for carrying the mandril in lieu of the bracket
arm before mentioned. The machine it will be seen possesses the general
characteristics of milling machines, a detailed description therefore of the
warious parts will not be required.
A, A, is the bed of the machine, cast with an opening through it corre-
sponding in form to the cross sectional profile of the stem of a vertical
sliding block B. One side of this stem is wedge shaped, and it is brought up
to and held in contact with corresponding guides formed on the bed by means
of a set screw C. The block B is cast hollow, but the bottom of the stem is
closed as shewn at Fig. 5; there is, however, a long slot bole left in the
bottom to allow a clamping screw D to pass up the block, and connect with
a slide E which the block is intended to carry, and also a round hole which
is tapped to receive the vertical screw F, by which the block, and consequently
the work which it carries, is raised or depressed as required. The screw F
is fitted with a collar which rests upon a bracket support G, bolted to the
under side of the bed of the machine, and its head is squared to receive a
spanner for turning it in its bearings. Mounted in bearings H, carried by the
bed of the machine, is a horizontal spindle I fitted with a hollow head, as
usual for receiving and driving the mandril K, which at its other end is
supported by a centre carried by a bracket arm L, forming part of or attached
to the casting which forms the bearings for the spindle I. To the mandril
K, the cutter M (which may be of any desired shape to suit the work in
hand) is made fast by a clamping nut in order that it may rotate therewith.
The spindle I is driven from the shaft N by spur gearing 1, 2, Fig. 2, which
carries two sets of band pullies, one set for receiving a band from the prime
mover, and the other for conveying motion by means of a band to pullies on
a shaft O, mounted in bracket bearings at the side of the machine (see Fig. 1);
a band P from a pulley on the inner end of this shaft is led up over guide
and tension pullies 3, 4, 5, for the purpose of driving a pulley Q which is
keyed to a slotted spindle R supported in a bearing carried by a bracket piec
S, made fast by bolts to the sliding block B; the tension pulley 3 is carried
by a stud in a fixed bearing, but the guide pullies 4 and 5 are fitted on studs
carried by the bracket piece S, and therefore rise and fall with the sliding
block. The spindle R is slotted to receive and drive a worm R' which is
carried to and fro by the lateral traverse of the slide E, by being let into a
socket formed in a bracket E' made fast to the slide E; this bracket E¹
carries a traversing screw shaft E for giving motion in the usual way to a
table T which carrres the work and presents it to the action of the rotary

page_text: cutter, a worm wheel Es fitted to the screw shaft Es gears into the worm R
and thus transmits the motion from the slotted spindle R to the traversing
screw. In order to arrest the motion of this screw when the work has passed
the cutter the worm wheel is connected to its screw shaft by a sliding clutch
U, Fig. 2; this clutch is embraced by a sliding piece U¹ fitted with a
handle for throwing the clutch in and out of action by hand when required,
but carrying a finger u, Figures 2 and 3; upon this finger takes a catch
formed on one end of a bell crank lever V, having as its fulcrum a pin on the
side of the slide E. Fitted to the table T is an adjustable stop t, which as the
table is traversed forward to pass the work under the cutter will strike upon
the raised end of the crank lever V, and tipping it will release the catch from
the finger u.
A strong coiled spring shewn in dots at W. Fig. 2, and pressing
upon the sliding piece U₁ with which it is connected will thrust it back and
with it the clutch, thereby arresting the action of the traversing screw. The
work is adjusted laterally to its cutter by means of an adjusting screw B¹
which is carried by the block B and works in a tapped lug carried by the slide
E. A vertical slot is made in the end of the bed A (see Fig. 4) to receive
this screw and allow of its moving up with the block B; when the slide
is adjusted it must be clamped to the sliding block by means of the screw
Luit D.
From the foregoing explanation it will be understood that when the block
B (which carries the slide and table for adjusting the lateral position of the
work and feeding it under the cutter) is required to be raised or lowered to
suit the size of the work it will only be necessary to slacken the set screw C
and to turn the screw F, by means of a spanner, and that to whatever position
the block may be adjusted within the extended range provided for it it will
still serve to support the work firmly and without vibration, thereby ensuring
good work while at the same time a greater variation in the sizes of the work
than was heretofore admissible in a milling machine will be effectually
provided for. I may here remark that the milling machine shewn in the
Drawing is adapted to operate upon long pieces of work intended to receive
say a transverse cut, for which purpose the work must be traversed laterally
under the cutter. It is however proposed in ordinary cases, in place of the
bracket arm which carries the centre, and for supporting the outer end of
the mandril, to employ the standard or poppet shewn at Figures 6 and 7.
Having now set forth the nature of my Invention of "Improvements in
the Construction of Milling Machines," and explained the manner of carrying
the same into effect, I wish it to be understood that under the above in part

page_text: recited Letters Patent I claim, the means above described for increasing the
range of milling machines and adapting them to operate with equal efficiency
on the largest as on the smallest pieces of work admissible thereto.
In witness whereof, I, the said Thomas Greenwood have hereunto set
my hand and seal, the Twenty-eighth day of November, in the year
of our Lord One thousand eight hundred and sixty-seven.
THOMAS GREENWOOD. (L.S.)