An Apparatus for Cutting Oval or Circular Holes, Applicable to Radial and other Drilling or Boring Machines.
Year: 1888

page_text: Date of Application, 11th Oct., 1888
Complete Specification Left, 11th July. 1889-Accepted, 17th Aug., 1889
PROVISIONAL SPECIFICATION.
An Apparatus for Cutting Oval or Circular Holes, Applicable to
Radial and other Drilling or Boring Machines.
I, ALFRED BLECHYNDEN, of Cavendish Park, Barrow-in-Furness, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
―
This invention relates to an apparatus adapted to be fitted to the spindle of a
drilling or boring machine by means of which elliptical or oval, as also circular, holes
may be cut out.
It is applicable to any drilling machine, the spindle of which is mounted on a
radial beam or in a freely sliding saddle, or which is fitted with a table, carrying the
work, which is free to move laterally, but I will describe it as applied to a radial
drilling machine to cut out elliptical or oval holes. The apparatus consists of a
radius bar fixed at right angles, by suitable means, to the spindle of the radial
drilling machine. At point on the radius bar, is a pin whose centre is at a
distance from that of the machine spindle equal to half the difference between the
major and minor diameters of the ellipse to be cut, and a cutting tool is secured upon
one of the projecting ends of the bar.
Upon the plate, or material, in which the hole is to be cut is fixed a guide plate
having formed in its upper side a straight slot in which a sliding block, fitting the
guide pin on the radius bar, or the pin itself works. This guide plate is fixed in such
a position that its centre corresponds with that of the ellipse to be cut and also with
that of the machine spindle, and the direction of the slot with either the major or
minor axis of the ellipse, and with a line drawn from the machine jib's centre of
rotation to the centre of the ellipse.
When the machine spindle, rotates, the apparatus, by the movement of the guide
pin in the slot, will cause the tool to approximately describe an ellipse whose major axis
coincides with; or is at right angles to, the line drawn from the jib's centre to the centro of
the figure according as the guide pin and the cutting tool are on the same or on
opposite sides of the machine spindle centro. The hole cut out by a radial machine
is not a truly symmetrical ellipse owing to the arc described by the lateral movement
of the end of the jib, but in the case of holes of the usual size required to be cut with
a machine of ordinary radius of jib the divergence from a true ellipse is unappreciable
for practical purposes. The apparatus when used with any other drilling, boring,
or similar machine, whose spindle is mounted in a saddle free to nove laterally, or
whose table is free to move or swing laterally is applied in a similar manner but where
the saddle or table move laterally in a straight line the figure described by the cutting
tool is a true ellipse. It is not essential to the apparatus that the various parts should
be capable of variable adjustment.
The guide pin may be fixed relatively to the spindle centre or the tool holder, as
may also the tool holder be-fixed/relatively to itheispindle so that a number of holes in
succession may be cut of the same size.

page_text: COMPLETE SPECIFICATION.
An Apparatus for Cutting Oval- or Circular Holes, Applicable to
Radial and other Drilling or Boring Machines.
I, ALFRED BLECHYNDEN of Cavendish Park Barrow-in-Furness in the County of
Lancaster Engineer do hereby declare the nature of said invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
This invention relates to an apparatus adapted to be fitted to the spindle of a
drilling or boring machine by means of which elliptical or oval, as also circular holes
may be cut out. It is applicable to any drilling machine, the spindle of which is
mounted on a radial beam or in a freely sliding saddle, or which is fitted with a table,:
carrying the work, which is free to move laterally, but I will describe it as applied
to a radial drilling machine to cut out elliptical or oval holes.
The apparatus consists of a radius bar fixed at right angles, by suitable means, to the
spindle of the radial drilling machine. At a point on the radius bar, is a pin whose
centre is at a distance from that of the Machine Spindle equal to half the difference
between the major and minor diameters of the Ellipse to be cut, and a cutting tool
is adjustably secured upon one of the projecting ends of the bar.
Upon the plate, or material in which the hole is to be cut, is fixed a guide plate
having formed in its upper side a straight slot in which a sliding block fitting the
guide pin on the radius bar, or the pin itself, works. This guide plate is fixed in such
a position that its centre corresponds with that of the ellipse to be cut and also with
that of the machine spindle, and the direction of the slot with either the major or
minor axis of the ellipse, and with a line drawn from the machine jib's centre of
rotation to the centre of the ellipse.
When the machine spindle is rotated the apparatus, by the movement of the guide
pin in the slot will cause the tool to approximately describe an ellipse whose major
axis coincides with, or is at right angles to, the line drawn from the jibs centre to the
centre of the figure, according as the guide pin and the cutting tool are on the same
or on opposite sides of the machine spindle centre.
The hole cut out by a radial machine is not a truly symmetrical ellipse owing to the
are described by the lateral movement of the end of the jib, but in the case of holes of
the usual size, required to be cut with a machine of ordinary radius of jib, the
divergence from a true ellipse is unappreciable for practical purposes.
The apparatus when used with any other drilling, boring, or similar machine, whose
spindle is mounted in a "saddle" free to move or swing laterally is applied in a
similar manner but where the "saddle" or table move laterally in a straight line the
figure described by the cutting tool is a true ellipse.
It is not essential to the apparatus that the various parts should be capable of
variable adjustment. The guide pin may be fixed, relatively to the spindle centre or
the tool holder, as may also the tool holder be fixed relatively to the spindle so that a
number of holes in succession may be cut of the same size.
DESCRIPTION OF DRAWINGS.
On the accompanying sheet of drawings the apparatus is shown as applied to the
spindle of a radial drilling or boring machine, the cutting tool and the guide pin being
on opposite sides of the centre of the spindle, to cut out oval holes of various sizes.
Fig. 1 is an elevation partly in section. Fig. 2 a plan. Fig. 3 an elevation, at
right angles to Fig. 1, and Fig. 4 an end view of the Tool holder.
A is the spindle in the socket of which is secured the box B carrying the sliding
radius bar in which is fixed the guide pin D and the projecting end of which carries
the adjustable tool holder E. The position of the guide pin D, relatively to the centre of
the spindle A, is adjustable to the size of the hole to be cut, the difference between

page_text: the two centres corresponding with half the difference between the major and minor
axis of the ellipse, and a scale on the end of the radius bar C determines this position
in which the radius bar C is fixed by set screws which enter a groove cut from end to
end of the bar. The plate. or other work in which the hole is to be cut, lies upon the
table F and the guide plate G is secured in position upon the plate by bolts which pass
through the plate and into the table. The straight slot in the guide plate is shewn
fitted with a sliding block H into which the end of the guide pin D is inserted. The
positions of the guide pin and of the tool holder shewn on the drawing will enable a
hole to be cut out corresponding to the smaller dotted outline shewn on plan Fig. 2
viz. 9 ins. x 7 ins. the difference between the centres of the spindle and of the guide
pin being 1 inch. If a hole is required to be cut out corresponding to the larger
dotted outline on plan Fig. 2 viz. 20 ins. x 15 ins. the guide plate G with the guide
pin D and the radius bar C must be shifted till the index shews 24 ins., as the
difference between the centres of the spindle and the guide pin, i.e. one half the
difference between the major axis (20 ins.) and the minor axis (15 ins.) of the hole
to be cut out, and the cutting tool is adjusted upon the radius bar to the proper
distance from the centre of the ellipse. The radial travel of the spindle in cutting
out an oval hole is equal to the difference between the major and minor axis of tho
ellipse.
When circular holes are required to be cut the guide plate and the guide pin are
fixed on the same centre as the spindle and the tool adjusted to the proper radius from
that centre. The apparatus may be used with other than radial machines, the neces-
sary lateral movement of the spindle being provided by means of a sliding "saddle,"
or the table may be free to move laterally in either of which cases the essential
features and the operation is the same.
وو
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is: :-
The apparatus for cutting out oval or circular holes, applicable to the spindle of a
radial drilling or boring machine, comprising a box B, revolving with the spindle and
moving radially therewith, when cutting oval holes, fitted with an adjustable, radius
bar C, on which is a guide pin D, working in a slot in a fixed guide plate G, and an
adjustable tool holder E; constructed and operating as described and shewn by the
drawing or in the alternative forms, applicable to non-radial drilling or boring
machines, in which the requisite lateral movement of the spindle to cut oval holes is
provided by a sliding saddle, or lateral movement is given to the table substantially as
desorihod
T TANNON
BIDA
T. J. DANSON, F.I.P.A.,
Offices for Patents, No. 2, St. Nicholas' Buildings, Newcastle upon Tyne,
Agent for Applicant.