IMPROVEMENTS IN MACHINERY FOR CUTTING DOVETAILS
Year: 1869

page_text: LETTERS PATENT to John Robinson, of Rochdale, in the County
of Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN
MACHINERY FOR CUTTING DOVETAILS."
Sealed the 1st January 1870, and dated the 7th July 1869.
PROVISIONAL SPECIFICATION left by the said John Robinson at the
Office of the Commissioners of Patents, with his Petition, on the
7th July 1869.
I, JOHN ROBINSON, of Rochdale, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTB
IN MACHINERY FOR CUTTING DOVETAILS," to be as follows:-
My Invention refers to that arrangement of machinery for which
Letters Patent were granted to Samuel Thomas Armstrong, dated
August 2nd, 1866, No. 2001, and consists,-
Firstly. In the adaptation of a guard or "fence" to the table, and
against which one end of the timber to be cut is placed. For this

page_text: purpose I propose to employ a bar connected to arms, which turn upon
centres and constituting an apparatus similar to one portion of a parallel
rule.
Secondly. I employ apparatus which enables me to adjust an angular
side of the timber for the action of the saws. For this purpose I employ
a guard or "fence," which turns upon a centre at one end, thereby
enabling me to place it at any angle, in which position it may be
retained by a tightening screw.
Thirdly. My Invention consists in an arrangement which enables me
to adjust the timber to be cut when different thicknesses are to be
operated upon. To accomplish this I mount the table so that it can be
caused to rise or fall through the agency of inclines, cams, or similar
apparatus, and I adapt a suitable arm or lever for effecting the required
motion.
Fourthly. I adapt a screw for running the table back after the cuts
have been effected. The arrangement I now propose is to gear this
screw with that which is ordinarily used for the feed motion, and to place
a nut between the two, which nut may be brought into gear with either
of them. The return screw may be driven at a higher speed than the
feeding screw.
SPECIFICATION in pursuance of the conditions of the Letters Patent;
filed by the said John Robinson in the Great Seal Patent Office on
the 7th January 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ROBINSON, of Rochdale, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of July, in the year of our
Lord One thousand eight hundred and sixty-nine, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Robinson, Her special license that
I, the said John Robinson, my executors, administrators, and assigns, or
such others as I, the said John Robinson, 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,

page_text: 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 DOVETAILS," upon the condition, amongst others, that I, the
said John Robinson, 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 John Robinson, do hereby declare
the nature of my said Invention, and in what manner the same is.
to be performed, to be particularly described and ascertained in and
by the following statement and accompanying Drawings, that is to
say:
My Invention relates to that arrangement of machinery for which
Letters Patent were granted to Samuel Thomas Armstrong, dated
August Second,. One thousand eight hundred and sixty-six, Number 2001,
and consists,
Firstly. In the adaptation of a guard or "fence" to the table, and
against which one end of the timber to be cut is placed.
Secondly. I employ apparatus which enables me to adjust an angular
side of the timber to the action of the saws.
Thirdley. My Invention consists in an arrangement which enables me
to adjust the timber to be cut when different thicknesses are operated.
upon.
Fourthly. I adopt a screw for running the table back after the cuts
have been effected.
And in order that my Invention may be fully understood I have
appended to this my Specification three Sheets of Drawings, which I
will now proceed to describe, in doing which I shall have to refer to
certain old parts of the machine, but will subsequently particularize
those which I claim as new.
Fig. 1 is a front view of the machine generally; Fig. 2 is an end view;
Fig. 3, an end view of the table looking in an opposite direction to
Fig. 2; Figs. 4 and 5, a plan and elevation of the table and parts
connected therewith taken in the direction of its traversing motion; and

page_text: Figs. 6, 7, 8, views of a guard or rence i employ for regulating the depth
to which the dovetails are to be cut.
The fast and loose pullies are shewn at 1 mounted upon the driving
shaft 2, upon which there is a pinion 3 driving an intermediate 4 which
is in gear with a wheel 5 upon the saw 6, and this saw drives the other
saw 7 by means of the wheels 8, these two saws being excentric on their
perepheries and set at an angle to each other, as in the known machine.
Upon the main framework 9 are V guides 10, upon which the lower
part 11 of the table is mounted so as to enable it to slide across the
machine, that is, in a line with the series of dovetails to be cut, and
upon this lower part is mounted on V guides 12 (see Fig. 5) the upper
part 13, which carries the timber forward towards the saws for the
necessary distance to effect the desired depth of dovetail. At 14 is a
slotted bar carried by the table and extending across it, and provided in
its slot with a moveable clamp or clamps 15, by which the timber may
be secured to the surface 16 of the table. Upon the shaft 2 is a pinion 18
taking into an intermediate 19, which drives a pinion 20 upon the axis
of the traversing screw 21, which (as seen in Fig. 2) is in gear with the
half nut 22 carried by the lower part of the table 11. At 23 is a lever
mounted upon a centre 24, which is provided with another lever 25
projecting into a slot formed in the upper part 13 of the table. By
turning this lever 23 therefore the table and timber thereon will be
caused to slide bodily forward for the necessary distance to effect the
required depth of cut, and a method I adopt for gauging such cut will
hereafter be described. The nut 22 is that commonly applied in this
machine for traversing the table, but according to my Invention I make
it double, the second half nut being at 26, and I also adapt a second
traversing screw 27, which is driven at a higher speed and in the
contrary direction by the pinion 26, which is in gear with another 28
of smaller diameter. Upon the top of the part 29 of the side framing
is mounted a plate 30 (see Fig. 6) so as to be capable of sliding thereon
in guides, such sliding motion being obtained by a lever 31, on the axis
of which is another lever 31* taking into a slot formed in the said plate.
At 32 is a fixed stop, but capable of adjustment and of registering the
position of the plate 30 by means of a pin 33. The plate 30 is provided
with a projecting bar 34, serving as a gauge or fence for the timber to
bear against before it is clamped, and thus determining the depth of cut,
and being attached to or formed upon the plate 30 may be moved into

page_text: pin 33 to abut against the stop 32. The above-mentioned fence does not
of course extend from the feed side (the right-hand of Fig. 1) quite up
to the saws, but terminates, as shewn, at 34*; and the position to which
it is moved for a given depth of cut is determined by a scale on the
stationary part, and to which the adjustable stop 32 is moved and
secured.
The general operation of the machine being known it will not here require
description, and I shall only refer to it so far as is necessary to explain
my Invention, reserving an explanation of two portions thereof, which
will be more clearly described separately. According to the positions of
the parts shewn in Fig. 1, the half nut 22 is in gear with the screw 21,
which is therefore traversing the table, and with it the timber across the
saws 6, 7. When this has been effected the table is drawn back as
usual, after which, according to the ordinary method the table is moved
longitudinally by hand to its former position; but according to my
Invention the drawing backward of the table from the saws is followed
by the bringing of the second half nut 26 into gear with the other
screw 27 in the following manner :-The lever 23 is provided with a
catch, which (as shewn in Figs. 1, 2,) is situate within a notch formed
As the table
in a lever 35, 35*, capable of turning upon a centre 36.
moves onward the part 35* of the said lever arrives in contact with a
fixed stop 37, and is thereby caused to turn upon its centre 36, by which
means the notch is disengaged from the catch, by which time the entire
breadth of timber has been operated upon. A further motion of the table
will now bring a roller 38 carried by an arm 39 on the axis of the
lever 23 beneath a fixed incline 40, by which means the said lever 23
will be turned upon its centre so as to move the table and bring the
nut 26 into gear with the screw 27, which by moving in an opposite
direction to the screw 21 returns the table by the driving power, and at
a quicker speed than that at which it moved forward, the pinion 28
being of smaller diameter than that by which it is driven. When this
has been done the nut 26 will have run off its screw, the, said screw
being discontinued at that part which corresponds to the end of the back
traverse of the table, and the backward movement of the table will thus
be arrested. The dovetailed board is now removed and another applied,
and in order to adjust it in its proper position the "fence" or gauge
constituting one part of my Invention is employed, as above described.

page_text: The board to be cut being thus adjusted and clamped down the table is
moved forward, and the lever 23 turned upward and its catch placed in
the notch of the lever 35, which movement will place the nut 22 into
gear with the screw 21, and the same operations as those above described
will be repeated.
Fig. 7, 8, represent a modification in construction of the above-
described fence or gauge. In this the gauging part 34 is jointed to two
links 50, 50, which at their other ends turn upon fixed centres 51, 51*,
carried by a stationary plate 52, and within which is a radial slot 53
provided with a pin 54, which may be tightened in any required position.
The fence 34 having been placed in the required position the link 50*
bears against the pin 54, while the board to be operated upon is clamped
to the table. In both these constructions of fence it will of course be
understood that when the table is moved towards the saws the said fence
is liberated from pressure, or is drawn back so as to allow the timber to
advance. It must also be understood that the usual fence for the end of
the timber to abut against, and for thus regulating the commencement.
of the series of dovetails is employed, but as it sometimes happens that
dovetails have to be cut upon boards with an angular side we modify
the said fence, as shewn in Fig. 4, in which 55 represents the fence
mounted so as to turn upon a centre 56, and provided with a handle 57
for that purpose, and the said fence may therefore be placed at any
angle to suit the angular side of the board to be cut.
Another part of my Invention relates to a method of elevating or
depressing the table, and is shewn particularly in Figs. 3, 4, and 5. The
upper part 57 of the table is provided with grooves, within which at
each end thereof is situate a dovetail piece 58 furnished at their under
sides with two wedge-formed parts 59, which are also dovetailed at their
bottom ends and extend into the portion 13 of the table. The pieces 58
are formed with nuts, in which are situate right and left handed screws
60, 61; by turning these screws therefore the wedges 59 may be caused
to approach or move from each other, and thereby raise the face 16 of
the table or allow it to fall. The shaft of the screws 60, 61, passes
through a slotted upright 62, on each side of which is a collar 63, and
the said screws are therefore held longitudinally, but their shaft may
move upward or downward in the slot of the part 62.
Having thus described and ascertained the nature of my said
Invention, and the manner in which the same is to be performed, I

page_text: desire it to be understood that I claim as applied to the aforesaid
description of machine,-
Firstly. The use of the fence shown particularly at Figs. 6, 7, and 8.
Secondly. The use of the fence turning upon a centre as 55.
Thirdly. Constructing the table so that the upper surface thereof may
be raised or lowered by inclines, cams, or equivalent apparatus.
Fourthly. The use of a screw for running the table back after the cuts
have been effected.
In witness whereof, I, the said John Robinson, have hereunto set
my hand and seal, this Sixth day of January, in the year of our
Lord One thousand eight hundred and seventy.
JOHN ROBINSON. (L.S.)