A MECHANICAL TABLE FOR FORMING OVAL OR CIRCULAR FIGURES
Year: 1884

page_text: I JAMES PARNELL TRUST SLADE, of Nº 131. Elizabeth Street Cheetham Man-
chester in the County of Lancaster Mechanic do hereby declare "the nature of my
invention for A MECHANICAL TABLE FOR FORMING OVAL OR CIRCULAR FIGURES
to be as follows:-
My invention is in the form of a table for carrying work to be punched drilled,
milled, slotted or otherwise shaped and causing the same to be wrought to an oval
or circular figure, or any part of an oval or circle, and with any proportion between
the major and minor axis of such oval.
The novelty of my invention is the formation of an oval or circular figure
without the rotation of either the work (as in the Oval Chuck), or of the tool (as in
oval boring machines) in which the tool describes an oval; thus enabling punching,
drilling, milling and slotting machines, with this table attached, to execute work of
an oval or circular figure, and on an object too large to be revolved.
I will now proceed to describe the said table.
I take a framework, upon the top side of which is a planed surface for a slide to
work upon, which I call the crown slide, and upon the bottom side of framework is
another planed surface to enable the framework to traverse upon a base-plate in
a direction at right angles to the line of motion of the crown slide.
Within the framework I place a worm wheel which has its bearing on its rim,
and is placed in such a position that its faces are parallel with the planed surfaces
of the framework, which framework is so constructed that the top and bottom faces
of the worm-wheel are open. Upon the framework are two lugs, between which
is a worm which I fasten with feather-keys. Across the top and bottom faces of
the worm wheel are two grooves, one in the top face and one in the bottom; these
grooves must go from one edge directly across the centre of the worm-wheel.
Within these two grooves I let two slides, which have a to and fro motion which
is obtained by means of two screws, by which screws the said slides can be wound
either to or from the centre of the worm-wheel; upon these slides I fix two blocks
which will revolve upon studs fixed in the slides.
One of these blocks fits into a groove in the base plate, upon which base-plate
the before mentioned framework slides; this groove is at right angles to the
direction in which the framework slides. In a suitable bearing on the base plate
is fixed the shaft upon which the beforementioned worm is keyed with feather

page_text: keys. The other block, which is fixed to the slide in the top face of the worm
wheel, works in a groove in the crown slide, which groove is also at right angles to
the direction in which the crown slide travels.
The motion is as follows: the worm is turned by the shaft; this causes tho
worm-wheel to revolve and the blocks that are on the slides in the worm wheel to
press against the cheeks of the grooves in the base plate and crown slide, thus
giving a to and fro motion to the framework and crown slide, and causing them to
travel at right angles the one to the other; the crown slide (upon which the work
is fixed) riding upon the framework, thus partakes of both motions.
When the slides in the worm wheel are placed equi-distant from the centre of
the same, any point on the crown slide will describe a circle, the size of such circle
being regulated by the distance of the slides from the centre of the worm wheel.
When the slides are placed at unequal distances from the centre of the worm-wheel,
an oval figure is formed, the proportions of the major and minor axis of such oval
depending upon the respective distances of the slides from the centre of the worm-
wheel.

page_text: Date T
Figure 2 Plan.
Figure 3 Sectional elevation parallel to worm-shaft.
Sheet 2 Figure 4 Sectional elevation at right angles to worm-shaft.
Figure 5 Plan with crown-slide removed.
Figure 6 Plan of part of base-plate.
The same letters of reference indicate the same parts in all the figures.
I take a framework A upon the top side of which is a planed surface B for
a slide C to work upon, which I call the crown-slide, and upon the bottom side of
framework is another planed surface D to enable the framework A to traverse upon
a base-plate E at right angles to the line of motion of the crown slide C.
Within the framework I place a worm-wheel F which has its bearing on its rim,
and is placed in such a position that its faces are parallel with the planed surfaces B
and D of the framework, which framework is so constructed that the top and
bottom faces of the worm wheel F are open. Upon the framework A are two
lugs GG, between which is a worm H.which I fasten with feather keys. Across
the top and bottom faces of the worm wheel F are two grooves II one in the top
face and one in the bottom; these grooves must go from one edge directly across
the centre of the worm wheel F. Within these two grooves II I let two slides KK,
which have a to and fro motion which is obtained by means of two screws L L by
which screws the said slides K K can be wound either to or from the centre of the
worm wheel F; upon these slides I fix two blocks M M, which revolve upon
studs 00, fixed in the slides.
One of these blocks M' fits into a groove P in the base plate E, upon which base
plate the before mentioned framework A slides; this groove is at right angles to
the direction in which the framework A moves. In a suitable bearing upon the

page_text: base plate E is fixed the shaft R upon which the .before mentioned worm H is
keyed with feather-keys. The other block M which is fixed to the slide K in the
top face of the worm wheel works in a groove S in the crown slide C, which groove
is also at right angles to the direction in which the crown slide travels.
On the worm H being turned by the shaft R, the worm wheel F is caused to
revolve, and the blocks M M' on the slides K K¹in the worm wheel to press against
the grooves P and S in the base plate and crown slide, thus giving a to and fro
motion to the framework A and crown slide C causing them to travel at right
angles the one to the other. The crown slido C, upon which the work is fixed,
riding upon the framework A thus partakes of both motions.
When the slides in the worm wheel F are placed equidistant from the centre of
the same, any point on the crown slide C will describe a circle, the size of such
circle being regulated by the distance of the slides from the centre of the worm
wheel. When the slides are placed at unequal distances from the centre of the
worm wheel, an oval figure is formed, the proportion of the major and minor axis
of such oval depending upon the respective distances of the slides from the centre
of the worm wheel.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
The mechanical table for forming oval and circular figures substantially as set
forth and described, and I further state that I do not restrict myself to the precise
details herein mentioned, as they may be varied without departing from the nature
of my invention,