IMPROVEMENTS IN MACHINERY FOR CUTTING AND SHAPING TOOTHED GEARING:
Year: 1858

page_text: LETTERS PATENT to John Potts, of 24, Park Street, Southwark, in the
County of Surrey, Pattern Maker, for the Invention of "IMPROVEMENTS
IN MACHINERY FOR CUTTING AND SHAPING TOOTHED GEARING:"
Sealed the 14th August 1858, and dated the 22nd February 1858.
PROVISIONAL SPECIFICATION left by the said John Potts at the Office
of the Commissioners of Patents, with his Petition, on the 22nd
February 1858.
I, JOHN POTTS, of 24, Park Street, Southwark, in the County of Surrey,
Pattern Maker, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN MACHINERY FOR CUTTING AND SHAPING TOOTHED GEARING," to
be as follows:-
My machinery or apparatus for cutting the teeth of wheels relates principally
to cutting the teeth of bevil or mitre wheels, but which is also applicable to
cutting spur gearing.
I mount the bevil wheel to be cut on a horizontal chuck or face plate, the
spindle of which is furnished with a dividing wheel and tangent screw, as used
in ordinary for cutting toothed wheels. In the end of the spindle above the
face plate I step a long vertical screw, which I fix at the upper end. On this
screw I mount a nut, carrying a short cross arm, which by the nut can be
traversed up and down the screw and fixed in any position. The framework
carrying the spindle has a long slide in a position radial to the face plate, on
which slide the carriage of the cutting tool traverses, and is adjusted nearer
to or further from the centre of the face plate, according to the size of the

page_text: wheel to be cut. A cross slide is mounted on the radial slide, the moveable
part of which is held in one direction by a spring and pressed against a pattern
tooth which regulates the shape of the tooth being cut.
From the cross slide
the lower end of a long inclined arm or beam is supported, the upper end of
which is carried to the cross piece mounted on the vertical screw before
mentioned. This beam carries at the lower end a slide, to which reciprocating
motion is communicated by a connecting rod & crank pin fixed in a spur
wheel mounted on the inclined slide and driven by suitable gearing mounted on
the radial slide. The inclined slide arm or beam is inclined at an angle to
suit the bevil of the wheel to be cut, for which purpose it moves on a pivot
fixed to the cross slide, and being connected to the cross arm on the central
upright screw, the upper end can be raised or lowered to suit any angle. It
is also furnished with a long slot, on which it can be traversed at its connec-
tion with the central upright screw, so that the slides may be adjusted nearer
to or further from the centre, according to the size of the wheel to be cut.
The sliding part of the cross slide carries a raised bracket, on which a short
slide is mounted on a centre pin. This slide is in a position transverse to the
inclined slide, which is affixed thereto, and can be moved on its centre pin,
as before-mentioned, and fixed by bolts moving in a quadrant slot in any
position according to the incline of the arm and slide. This slide carries a
truck roller or point bearing against the pattern tooth, which regulates the
shape of the tooth of the wheel being operated upon. The motion of the
incliued slide produces the cut across the breadth of the tooth, while by moving
the point or roller gradually over the pattern tooth or surface (by the-last-
mentioned slide) during the successive cuts of the tool the side of the tooth
of the bevil wheel will be formed of an exactly similar shape. By repeating
the operation on both sides of the several teetli of the wheel, they will all be
trimmed & shaped of the same form.
It will be recollected that the lower slide, placed transversely to the radial
slide, is pressed against the pattern tooth by a spring; the cutting tooth is
arranged also to exert a pressure in the same direction; while cutting, a small
slide fixed on the inclined slide carries the tool, and is used simply for adjust-
ing the tool.
This apparatus may be made sufficiently strong and applied for turning the
wheels previously to cutting them. It is also applicable for cutting spur gear,
the only change required for this purpose being to place the inclined arm or
beam before-mentioned in a vertical position, that is to say, parallel with the
axis of the wheel to be operated on.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Potts in the Great Seal Patent Office on the 21st
August 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
POTTS, of 24, Park Street, Southwark, in the County of Surrey, Pattern
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of February, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Potts, Her special licence that I, the said John Potts, my
executors, administrators, and assigns, or such others as I, the said John
Potts, 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 and 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
MACHINERY FOR CUTTING AND SHAPING TOOTHED GEARING," upon the condition
(amongst others) that I, the said John Potts, my executors or adminis-
trators, by an instrument in writing under my, or their; or one of their
hands and seals, should particularly 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.
I NOW KNOW YE, that I, the said Johu Potts, 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 and accompanying Drawings, that is to say :-
This, the Specification and description of my Invention as described
hereunder, is in general terms and using common mechanical appliances so
arranged and combined that they produce on any material, such as wood, iron,
stone, &c., a shape or form which may have for its section any curve or figure,
but longitudinally on its face a straight line or the plane of the face shall
always verge, point, or cut to a centre point, as, for instance, in either bevel
or skew gear the stroke of tool will be always in such lines as indicated by
'

page_text: (or any) given point, as C, which in skew gearing might not be in the centre.
line of either shaft, though nevertheless every stroke of the cutting tool by
this my new Invention will, upon any circular ring, as a toothed wheel, form,
cut, or tear away the material, and leave projections to any sectional shape
that may be required. The face or side, as of the tooth of a bevel wheel, shall
in all cases point to a centre.
A
First, thus, in Drawing No. 1, shewing my appliances for the vertical
machine here A, A, is the main arm or beam, adjustable by means of the
centre pin B and slide block C, O; the arm being slotted, and also the bed, so
that either may approach or recede from the mandril or plate upon which the
wheel, ring, or block may have been fixed, thus allowing every latitude for
adjusting the arm to the bevel or angle that may be required for setting up
the tool to its work.
The remainder of the description for this the vertical machine will also.
answer for and explain the horizontal, by referring to Drawings No. 1 and.
No. 2, the letters and words being applied to both, they being the same in
principle.
No. 2: A, A, is the arm or beam already referred to in the vertical machine,
similar in its action and principle, but altered in arrangement, as may be thus:-
The arm carrying the cutting tool is faced in this instance on the inner sides a, a,
in which the slide block is fitted b, b, and which is here worked by connecting
rod or link c, c, taking its throw or stroke from a driving wheel, as d, d, which
may be geared or driven in any of the ordinary ways by bevel, spurs, or strap
gearing, &c., as in common practice; the length of stroke being regulated
by means of the adjusting centre e, e, sliping in a slot with a T and lock nut,
so as to act as an eccentric. The tool in this instance is put through a square
hole f, f, and jambed well up by the screws g, g, into the circular tool block.
h, h, and which tool block is turned and fitted into another plaining or slotting
block i, i, in such a manner that first by means of the worm and partly cut
thread j, j, the tool itself may be thrust forward at any time to its required
distance, without disturbing any other part of the machinery, either before
commencing operations or after the tool may have been repaired.
In the next place the planing or slotting box is similarly fitted with joint
k, k, and bearing piece l, as in most of the ordinary machines for planing and
slotting. The joint m, m, may be a common rule joint or otherwise, so long
as it allows the tool to leave its cut in the reverse stroke, whether it cut
forward or backward, up or down, or for facing and bottoming, should all
these operations be performed after the manner of planing or slotting. But
be it remarked that in this machine, as in the vertical one already described,

page_text: the face, back and front, may be turned up, as well as the pitch line put on,
similar as in the ordinary lathe, by means of turning the wheel on the
mandril n, n, either by connecting with back driving gear, strap, gut, or other
motion similar to the common lathe, and fixing the wheel to be operated upon a
mandrel or face plate by clamps, screws, or other means in ordinary use. The
wheel turning and the tool being advanced by either of the screws j, j, or p, p,
as may be required, or by the wheel and connecting link d, d, and c, c.
Where slotting or planing is performed.-In this case of the horizontal
machine, the arm A, A, still performs the same office or answers the same
purpose as in the vertical machine, inasmuch that by adjusting the centre B,
and advancing or withdrawing the bed block C, and fixing each at their
required distances by means of the bed blocks or similar adjuncts, according
to the bevel. The peculiarity of this contrivance is still carried out in respect
to the Invention claimed, that in every instance the stroke of the tool, let
it be placed where it may, always so far as mechanically practical, takes its
cut and stroke invariably to the centre, to be regulated according to size and
requirements of the machine.
The form of shape of curve to be cut q, q, is placed and jamed up in a box
beneath the bearing guage r, r, attached to the swivel block C, C, so that in
all positions it may be acting upon its mould or form, and retained hard down
upon it by means of the spiral spring D, D, dragging and bearing all hard
down upon the centre, and hence upon any form that may be there placed.
I claim as my Invention, not the ordinary mechanical usages, but most
particularly the having the arm A, A, adjustable to any angle, and yet retaining
the means and apparatus for planing or slotting to any figure required, and
always to a centre.
In witness whereof, I, the said John Potts, have hereunto set my hand
and seal, this Twentieth day of August, in the year of our Lord One
thousand eight hundred and fifty-eight.
JOHN POTTS.
(L.S.)