Improvements in or relating to Dovetail Mortising Machines.
Year: 1895

page_text: Date of Application, 31st Dec., 1895-Accepted, 1st Feb., 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Dovetail Mortising Machines.
A communication by CHARLES CRISTADORO, of St. Paul, in the County of
Ramsey, and State of Minnesota, United States of America, Manufacturer..
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, 118 New Street, Birmingham in
the County of Warwick and 31 High Holborn in the County of Middlesex.
Civil Engineer, do hereby declare the nature of this 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 improvements in machines designed to cut mortises in
the ends of the sides of box boards, to receive, corresponding tenons upon the end
boards of the box; its object being to provide an improved machine adapted to cut
a series of mortises in a plurality of boards in one operation. To this end the
invention consists in providing a gang of cutters, adapted to cut straight grooves.
with parallel sides in the stock as passed over them. Arranged to travel past
these cutters is the slidable frame or clamp having rocking angle blocks on opposite
sides, between which the boards are placed and held at the same angle with the
When
path of the cutters as the desired dovetail angle of the mortise to be cut.
thus placed; the boards are clamped and held firmly in position so that the grooves
cut may be absolutely unvarying. The first part of the operation being completed,
which consists of the cutting of the series of grooves with the travel of the stock
over the cutters, the clamp is loosened and the angle blocks reversed so as to turn
and hold the stock at an exactly opposite angle, the clamp being again tightened.
The frame or table is provided with shifting devices whereby the frame with its
load can be moved laterally to compensate for the variation between the positions
of the grooves first cut in the boards, with the path of the cutters, so that on the
reverse movement of the stock in the second part of the operation the cutters
will enter the throats or adjacent ends of the grooves cut in each board, and cut
away one of the side walls of the grooves so as to shape them into the required
dovetail form.
This invention further consists in the specific construction and combination
hereinafter described and particularly pointed out in the claims.
In the accompanying drawings forming part of this Specification;
Fig. 1 represents a plan view of the device showing the position of the clamping"
frame in which the stock is held, in relation to the cutters, and the clamping
attachments therefor, and the means for shifting the frame laterally;
Fig. 2 is a side elevation of the same;
Fig. 3 is a plan view of the clamping frame, one position of the stock being
indicated by full lines and the reverse position by dotted lines, and
Figs. 4, 5, 6 and 7 respectively illustrate diagrammatically the position of the
stock when adjusted to receive its first cut, its position when tilted to the opposite
angle, its position when laterally shifted to bring the openings of the grooves cut
by the first operation into line with the cutters, and the form of the mortises cut
by the two operations therein.
In the drawings 2 represents the bed of the machine upon which the table A i;
arranged to slide laterally in suitable guides 3. At the sides of the table are

page_text: arranged the stops 4 and 5 limiting its lateral movement. The lever 6 pivoted to
the bed of the machine, and connected by the link 7 to the table, serves to move
the same laterally between the stops, as hereinafter described. Mounted upon the
table A to slide longitudinally of the machine is the frame B. The clamp screw 8
provided with the band wheel 9, mounted upon the table A and threaded into the
table B, serves to drive the table B along the frame A in the operation of the
machine. Upon the table B is mounted the clamping frame C consisting preferably
of the side bar 10 and the end pieces 11 rigidly secured to, and formed integral
with, the bar 10, and at right angles therewith. The bar or frame piece 12 parallel
with the piece 10, slides on guides 13 to and from the piece 10, so as to vary the
width of the frame, the springs 14 between the members tending to throw the
movable piece 12 outward. Pivoted securely to the members 10 and 12 at or near
their centres, are the rocking angle blocks 15 in the form of an isosceles triangle,
the equal angles of which correspond to the angle of the dovetail to be cut in the
stock. Between these blocks are placed boards or pieces of stock 16 which are
firmly secured in the required angular position by means of the eccentric roll or
cylinder 17 arranged parallel with the bar 12 and provided with the handle 18, by
means of which it may be turned in its bearings to crowd the bar 10 inward against
the tension of the springs, and firmly clamp the stock between the blocks.
order to hold the stock in contact with one of the end pieces or bars 11 so that the
notches or mortises cut therein shall be at exactly the same distance from the edge
of all the boards, my correspondent arranges a set screw 19 in one of the end
frame pieces adapted to bear upon the follower 20 arranged transversely in the
frame and bearing upon the sides of the stock, thus pressing them against the
opposite end of the frame, and holding them in contact with it. Arranged in
suitable bearings (not shown) upon the machine, are the series of cutters 21 which
project upward through the slotted openings 22 in the table B, so as to be brought
into contact with the stock held in the frame C, and cut a series of grooves in the
stock, as it is carried by the table B over them.
In
In Figs. 4, 5, 6 and 7 are illustrated the different positions of the stock in
relation to the cutters, and the work done by them therein. Fig. 4 illustrates the
position of the stock to receive the first cut, the angular position being indicated
by the dotted lines in Fig. 3. The paths of the cutters 21 are indicated by the
dot and dash lines, and with the first part of the operation, the straight grooves 23
are cut through the series of boards, which being placed at an angle with the plane
of the cutters, the grooves cut are at the same angle through them. After the first
cut the lever 18 is turned to release the clamp, and the set screw 19 is loosened,
when the angle blocks may be rocked carrying the stock into the position
illustrated in Fig. 5. It is evident that the openings or ends of the notches on the
sides of the boards toward the cutters, will then be out of alignment with them, and
the stock must consequently be moved laterally to bring them into alignment,
which adjusted position is illustrated in Fig. 6. The stock being then carried past
the cutters, they cut away one wall of the notches in the boards, as indicated by
the dot and dash lines, thus forming the dovetail notches 24, as shown clearly in
detail Fig. 8 adapted to receive corresponding tenons on the outer box boards..
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent I declare that what I claim is:
1. The combination with the series of groove cutters, of means for presenting a
plurality of pieces of stock to said cutters whereby a series of parallel grooves is
cut in the edges of the stock, means for shifting all of said stock to a predetermined
angle with its first position, for shifting each piece laterally with reference to the
adjacent pieces, and for laterally shifting the position of all the stock with
reference to the cutters, whereby in presenting the same a second time to said
cutters one side of the grooves in the several pieces of stock is cut away to form
similar dovetail notches, substantially as described.

page_text: 2. The combination with the series of groove cutters, of means for holding a
plurality of pieces of stock at a predetermined angle with the path of the cutters,
means for shifting said angle a predetermined degree, means for uniformly shifting
the several pieces of stock laterally with reference to each other a predetermined
distance, means for laterally shifting all of the stock a predetermined distance, and
means for presenting said stock to said cutters, substantially as described.
3. The combination with the clamp, of the angle blocks respectively pivoted to
the members of the clamp and adapted to be set to hold the stock in either of two
similar but opposite angular positions, and the follower and its screw adapted to
hold the stock against one end of said clamp, substantially as described.
Dated this 30th day of December 1895.
WM. P. THOMPSON & Co.,
Agents.