IMPROVED. MACHINERY POR CUTTING DOVETAILS AND TENONS
Year: 1855

page_text: LETTERS PATENT to Henry William Wimshurst, of St. John's Wood, in.
the County of Middlesex, Gentleman, for the Invention of "IMPROVED.
MACHINERY POR CUTTING DOVETAILS AND TENONS."
Sealed the 29th February 1856, and dated the 21st November 1855.
PROVISIONAL SPECIFICATION left by the said Henry William Wims-
hurst at the Office of the Commissioners of Patents, with his Petition,
on the 21st November 1855.
I, HENRY WILLIAM WIMSHURST, of St John's Wood, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention for
IMPROVED MACHINERY FOR CUTTING DOVETAILS AND TENONS, to be as follows:
This Invention relates to a novel arrangement of machinery for facilitating
the cutting of dovetails and tenons. To this end I provide a series of spindles,
which I mount horizontally in a fixed frame, and drive by means of bands,
which severally pass from a common drum to a pulley keyed on to the spindles.
On to each end of these spindles I fit a rotary cutter, one of which is cylindrical,
or has a square cutting edge, and the other is made conical, that its cut may
correspond in form with the curved cut produced by the cylindrical cutter.
The wood I feed up to the cutters by means of a rising table, and the advance
of the wood to the cutters I adjust by suitable gauges. It will be understood

page_text: that to cut dovetails of various sizes the cutters must be changed, and that
they must always be made in pairs to suit each other and produce cuts which
shall correspond in form. As the conical cutter passes directly through the
whole thickness of the wood, it will be necessary in order to ensure a clear cut
to provide a support for the edges of the wood, and this I do by shaping an
underlying metal bar with slots at its edge, corresponding to the form of the
conical cutters, and of just sufficient size to allow of the table which carries the
plate passing up the clear of theso cutters. When cutting tenons with this
machine the cylindrical cutters only are employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry William Wimshurst in the Great Seal Patent Office
on the 21st May 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
WILLIAM WIMSHURST, of Saint John's Wood, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of November, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry William Wimshurst, Her special license that I, the said Henry
William Wimshurst, my executors, administrators, and assigns, or such others
as I, the said Henry William Wimshurst, 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 "IMPROVED MACHINERY FOR CUTTING, DOVETAILS AND TENONS," upon the con-
dition (amongst others) that I, the said Henry William Wimshurst, by an
instrument in writing under my hand and seal, 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.
NOW KNOW YE, that I, the said Henry William Wimshurst, do hereby
declare the nature of my said Invention, and in what manner the samo is
to be performed, to be particularly described and ascertained in and by the

page_text: following statement, reference being had to the Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
This Invention relates to a novel arrangement of machinery designed to
facilitate the cutting of dovetails and tenons, and specially applicable to the
manufacture of packing cases, tea chests, and other boxes.
In the accompanying Drawings, Fig. 1 shews my improved machinery in
side elevation; Fig. 2 is a plan view of the same; and Fig. 3 is an end eleva-
tion. The machine consists of a series of spindles, fitted at their opposite ends
with chisel-edged cutters, and mounted horizontally in a fixed frame. These
spindles are each provided with a pulley, which receives a driving band from a
common drum, the rotation of which gives a rapid rotary motion to the cutters.
The wood to be dovetailed or tenoned is fed up to the two rows of cutters
by means of ascending tables, fitted one at each side of the machine, and self-
acting nipping apparatus is provided for retaining the wood in position on the
tables while the cutting is proceeding.
I will now proceed to describe in detail my improved machine.
a, a, is the
main framing, and 6 the bed plate to which it is bolted. This bed plate is fitted
with bearings which carry the main driving shaft c. d, d, are the fast and
loose pulleys on the shaft c, and keyed to the same shaft is a large drum e and
a small pulley f. The cutter spindles are shewn at g, g, arranged all in the
same plane and lying parallel with each other in bearings provided for them in
the upper part of the framing a. For cutting dovetails, these spindles are pro-
vided at their opposite ends with cutters of different forms, which forms bear
a certain relation to each other, in order that the dovetails made by the one set
of cutters may exactly correspond with the dovetail recesses made by the other
set to receive the dovetails. This will be better understood by reference to
Figures 4, 5, and 6, which illustrate the mode of cutting the dovetails and of
fitting the parts together. The cutter, Fig. 4, it will be seen is formed and
operated so as to make a cut corresponding to the segment of a cylinder, the
wood not being permitted to pass or come up to the axial line of this cutter.
To form a dovetail which shall correspend in figure with this cut, the hollow
or concave-faced cutter, Fig. 5, is employed, and it is operated so that its
largest diameter shall act upon and pass through the wood; counterpart
recesses are by this means formed in the edges of the wood under operation,
so that when put together a firm dovetail joint is produced, like that shewn at
Fig. 6. The cutters, it will be understood, on inspecting Figures 5, are tapped
into the ends of the spindles g, and they therefore admit of being readily
removed to be sharpened or replaced by others of different dimensions as
required. As the cutters are attached to opposite ends of the spindle, it will

page_text: be necessary to tap one set with a right and the other with a left handed screw,
to ensure the cutters retaining their places in the spindle ends. Keyed to
each spindle g is a pulley h, which receives motion from a strap or band i, pro-
ceeding from the large drum e. The wood to be dovetailed is placed on the
tables at either side of the machine, where it is held fast by an arrangement
of nipping apparatus, and presented to the cutters. These tables slide up and
down in vertical guides made for them in the main framing. Their vertical
motion is obtained by the rotation of a crank shaft l, which has its bearings in
the main framing a, and is connected to the tables by crank rods m, m.
Keyed to the crank shaft is a large spur wheel n, which gears into a pinion on
a stud axle o, supported in bracket bearings. This stud axle carries a pulley
p, which receives a band or cord from the pulley f on the main driving shaft c.
It will now be seen, that as the shaft c revolves a slow reciprocating motion
will be given to the tables, the amount of which will be determined by the throw
of their respective cranks. Affixed to the upper part of each table is a cross
head q, to the middle of which a weighted lever is jointed. This lever rests
upon an adjustable plate.s, standing up from the main framing a, and this lever
serves to carry by means of links a sliding presser plate t, which when in action
lolds down the wood (to be cut) firmly on the table, and is capable of moving"
up and down in guides in the sides of the cross head q. The height of each.
plates (which sorves as a fulcrum for the rocking lever r) is so adjusted, that,.
as the table rises to bring the wood up to the cutter, the weighted end of tho
lever will be depressed, and will carry with it the presser plate t, and keep it
in close contact with the wood on the table. When the table has risen to
its highest position the cut will have been completed, and the table will then
immediately (by reason of the continuous motion of the crank by which it
is actuated) commence its descent. This downward movement will cause tlie
rise of the weighted end of the lever, and consequently the release of the
dovetailed wood from the pressure of the plate t. The attendant now removes
the wood from the table, and replaces it by a fresh piece, which is in like
manner operated upon.
As the series of concave cutters (see Figures 5) pass through the whole
thickness of the wood, it is desirable, in order to ensure a clean cut, to provide a
support for the lower edge of the wood. This I do by shaping an underlying
bar (affixed to the edge of the table), with slots at its edge, corresponding to
the form and position of the rotary cutters. As, therefore, the table rises, the
cutters will pass through the wood and through the slots in the plate. In
preparing wood in great quantities with dovetailed edges, I propose to pile up
several boards one upon the other, and submit then in a pile to the action of the

page_text: concave surface cutters.
The cutters will then as the table rises pass through
the mass of boards and form dovetail recesses therein. But as it is impossible
to act in like manner on a pile of boards with the other cutters, it may be
convenient to fit up machines specially for each operation, one machine being
fitted solely with the hollow or concave-faced cutters, and two or more
machines being employed to produce the segment cut; the fact of having to
present the boards singly to the action of the cutters which produce the seg-
ment cut rendering this operation more tedious than the cutting of the
dovetails by the hollow-faced cutters. In order to ensure the proper depth of
segment cut in the boards, I make the rod which connects the crank shaft
with the table that carrries the boards up to the segment cutters adjustable in
its length, as shewn by dots at Fig. 1, and I thus obtain the exact lift desired.
It will be seen that the screwed end of a forked piece which is jointed to
the connecting rod passes through a lug attached to the table, and by means of
two nuts, one on either side of the lug, the lift of the table may be adjusted
with the greatest nicety. When cutting tenons with this machine, the adjust-
ment of the connecting rod must be such that the table will in rising carry
the wood past the axial line of the cutter. For adjusting the wood on the
tables, I provide shifting stops t, u, which, by a similar arrangement of double
nuts, permit of the wood being set to any required position with respect to
the cutters.
Having now set forth the nature of my Invention of "Improved Machinery
for Cutting Dovetails and Tenons," and explained the manner of carrying the
same into effect, I wish it to be understood that I claim,-
First, presenting the wood to be cut to the action of a series of rotating
cutters by means of ascending tables, as described.
And, secondly, the application of counterpart cutters fitted on the extre-
mities of a series of rotating spindles mounted in a fixed frame, as described..
In witness whereof, I, the said Henry William Wimshurst, havo
hereunto set my hand and seal, the Twenty-first day of May, in the
year of our Lord One thousand eight hundred and fifty-six.
Witness,
FRED. WALKDEN,
66, Chancery Lane.
II. W. WIMSHURST. (L.S.)