IMPROVEMENTS IN MORTISING MACHINES."
Year: 1876

page_text: LETTERS PATENT to Thomas Edwin Craven, of Leeds, in the County of York,
Engineer, for the Invention of "IMPROVEMENTS IN MORTISING MACHINES."
PROVISIONAL SPECIFICATION left by the said Thomas Edwin Craven at
the Office of the Commissioners of Patents on the 26th January 1876.
THOMAS EDWIN CRAVEN, of Leeds, in the County of York, Engineer.
PROVEMENTS IN MORTISING MACHINES."
"IM-
This Invention of improvements in mortising machines mainly relates to a novel
method of connecting the hand lever of a mortising machine to the part which
carries the cutting tool or chisel, the object being not only to produce the requisite
vertical motion of the cutter or chisel, but to do this in such a way as to give
increased force to the cutter or chisel as it penetrates deeper and deeper into the
material operated upon.
The hand lever is so made as to form by one or more parts a "toggle lever," to
which is jointed by means of a joint pin the upper end of a "toggle link," the lower
end of which link is connected by another joint pin to a part called a sleeve or
socket through which the cutter spindle passes. The upward and downward
motion of the hand lever imparts a vertical reciprocating motion to the spindle and
cutter or chisel, the action of the "toggle lever and link "being such as to give an
increase in power as the penetration of the cutter or chisel becomes deeper in the
material operated upon. The cutting motion is performed by the downward motion
of the hand lever and the withdrawal of the cutter or chisel by the upward motion
of that lever. On one side of the sleeve or socket through which the spindle
passes is formed a plane or sliding surface which takes a bearing against a corre-
sponding surface, which may be either on the front part of an upright or standard
or on an intermediate part fixed to the standard, which intermediate part or standard
may carry the bearings through which the spindle slides and also the fulcrum of
the hand or toggle lever; the intermediate part may be raised or lowered to suit
the depth of material to be operated upon, and also to determine the depth of
mortise when not required to pass through the said material; and in order to
determine the length of mortise required the material under operation may be
moved forward by suitable slides and gearing connected with the moveable bed on
which it is fixed.
The cutter spindle is so attached to the sleeve or socket through which it passes

page_text: as to admit of an axial motion within it for adjusting the angular position of the
cutter or chisel, as may be desired; this is done by having at one end of the sleeve
or socket a projecting flange, on the periphery of which are two notches diametrically
opposite each other, and into which notches a pin or catch takes alternately as the
axial motion of the spindle is effected by means of a handle provided for that
purpose in which the pin or catch is inserted, this pin or catch being moved end-
wise and pressed into the notches in the flange of the sleeve or socket by means of
a helical or other suitable spring within or on the handle.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Edwin Craven in the Great Seal Patent Office on the
22nd July 1876.
THOMAS EDWIN CRAVEN, of Leeds, in the County of York, Engineer. "IMPROVE-
MENTS IN MORTISING MACHINES."
This Invention of improvements in mortising machines relates to a novel method
of connecting the hand lever of a mortising machine to the part which carries the
cutting tool or chisel, the object being not only to produce the requisite vertical
motion of the cutter or chisel, but to do this in such a way as to give increased
force to the cutter or chisel as it penetrates deeper and deeper into the material
operated upon.
The hand lever is so made as to form by one or more parts a "toggle lever," to
which is jointed by means of a joint pin the upper end of a "toggle link," the lower
end of which link is connected by another joint pin to a part called a sleeve or
socket through which the cutter spindle passes. The upward and downward
motion of the hand lever imparts a vertical reciprocating motion to the spindle and
cutter or chisel, the action of the "toggle lever and link" being such as to give an
increase in power as the penetration of the cutter or chisel becomes deeper in the
material operated upon. The cutting motion is performed by the downward motion
of the hand lever and the withdrawal of the cutter or chisel by the upward motion
of that lever. On one side of the sleeve or socket through which the spindle
passes is formed a plane or sliding surface which takes a bearing against a corre-
sponding surface, which may be either on the front part of an upright or standard
or on an intermediate part fixed to the standard, which intermediate part or standard
may carry the bearings through which the spindle slides and also the fulcrum of
the hand or toggle lever; the intermediate part may be raised or lowered to suit
the depth of material to be operated upon, and also to determine the depth of
mortise when not required to pass through the said material, and in order to
determine the length of mortise required the material under operation may be
moved forward by suitable slides and gearing connected with the moveable bed on
which it is fixed.
The cutter spindle is so attached to the sleeve or socket through which it passes as
to admit of an axial motion within it for adjusting the angular position of the cutter
or chisel, as may be desired; this is done by having at one end of the sleeve or
socket a projecting flange, on the periphery of which are two notches diametrically
opposite each other, and into which notches a pin or catch takes alternately as the axial
motion of the spindle is effected by means of a handle provided for that purpose in
which the pin or catch is inserted, this pin or catch being moved endwise and
pressed into the notches in the flange of the sleeve or socket by means of a helical
or other suitable spring within or on the handle.
DRRVAG

page_text: showing more particularly the improved motion for actuating the cutter spindle or
slide, the top, intermediate, and the bottom positions of the toggle lever and link
being shewn in dotted lines.
A is the bed of the machine; B the upright or standard; C is a compound slide,
capable of being moved on the bed by the hand wheel D and screw E, for the
lateral adjustment of the mortises F, the cross bed with clamping screw G, for
holding the wood to be mortised, having the cross notion imparted to it by the
land wheel H, pinion I, and rack J; K is the cutter spindle, which carries the
cutting tool L in its lower end in the usual way; this spindle slides vertically
through the bearings M' and M on the intermediate part M, which is checked in
and secured to the front of the upright or standard B by the bolts 0, 0, and is
adjustable vertically as required by means of the screw P and handle P. The
screw P takes into a tapped lug M³ on the intermediate part M, and has its bearing
on a projecting lug Q on the top of the upright B. The spindle K passes through
the sleeve or socket R, which has a flat surface at the back taking and sliding
against a corresponding surface on the part M, and is thereby kept in the same
angular position; the sleeve or socket R is secured to the spindle K by being
confined between the boss of the handle S and the collar T, so that they may move
up and down together, while at the same time the spindle K with the cutter is free
to receive an independent axial motion by means of the handle S, which is fixed to
the cutter spindle by means of a set screw or otherwise, and is provided with a
sliding pin or bolt N actuated by a helical or other suitable spring, by which it is
made to take and lock alternately into the notches or divisions N and N2 provided
in the flange of the sleeve or socket R shewn in plan, Fig. 4, Sheet 1. When the
cutting edge of the chisel requires to be reversed to permit the completion of the
starting end of the mortise the handle S with the spindle K is moved horizontally
until the bolt N is withdrawn from one notch (in which it must always be on
commencing a mortise) and made to take into the opposite one, when a few strokes
of the hand lever W will complete the mortise. On the front of the upper bearing
of the spindle on the part M is a lug or projection U, which is pierced horizontally
to receive the fulcrum or joint pin U₁ of the toggle part V of the hand lever W,
the toggle part being adapted to fit the said lug; the other end of the toggle part is
also adapted to fit one end of the link X; the lever and link are jointed together so
as to work freely by the joint pin X¹, the other end of the link X is similarly jointed
to the sleeve R by the pin X, thus completing the connection between the hand
lever W. and the cutter spindle K ; when therefore the hand lever W is actuated by
the operator a vertical up and down motion will be imparted to the spindle K and
to the cutting tool L at the lower end of the same, the motion so imparted being one
decreasing in proportion to the movement of the hand of the operator, thereby
increasing the purchase or power over the work to be performed as will be seen by
reference to Fig. 3, Sheet 1. Where the motion of the spindle K in the first portion
of its descent from Y to Z and. when the chisel begins to penetrate the wood,
and the least force is required, is nearly equal to that of the joint pin X¹ of the
toggle lever V, while the last portion of the stroke of the spindle, namely from Z to
Z is one greatly and continually diminishing from that of the joint pin X¹ of the
toggle lever V, which passes through about 50 per cent. more space than the spindle
Kmoving from Z to Z, thereby increasing considerably the penetrative force of
the chisel as it passes deeper and deeper into the wood. W is a counterbalance for
the hand lever and its various connections.
Fig. 5 (Sheet 2) shews a modification in which the arrangement of hand or toggle
lever V, W, and link X is placed in a similar position to that described with
reference to Figs. 1, 2, and 3, Sheet 1, but with a separate resisting part U for the
fulcrum U¹; the said part U is capable of being raised or lowered by means of the
screw P and handle Pl for regulating the depth of penetration of the chisel L.
Fig. 6 (Sheet 2) shews the hand lever W with its toggle part V formed in one
piece, and which said hand lever with its toggle part may, by making a slight

page_text: modification in the form of the upright or standard B, be made as shewn in Fig. 7,
Sheet 2.
In making blind mortises, or such as do not require to pass through the wood, the
depth of such mortises and the regularity thereof is obtained as follows:-First
place the joint pins X1 and X so that they come into a line with the centre of the
fulcrum U, whether the same be placed in a vertical or in any other position, or in
other words, place the spindle K and the chisel L, Figs. 1 and 2, Sheet 1, or the slide
M with its spindle K and chisel L, Fig. 5, Sheet 2, in the lowest position by moving
down the hand lever W to its lowest point, then raise or lower the part M in Figs. Ĭ
and 2, Sheet 1, and the part U in Fig. 5, Sheet 2, carrying the fulcrum U until the
chisel comes to the position representing the required depth of mortise, the part M,
Figs. 1 and 2, Sheet 1, and the part U, Fig. Sheet 2, must then be fixed by the
bolts O. Then at every stroke the hand lever W must be brought down to its lowest
point and proceed as in ordinary mortising.
Having now described the nature of my said Invention of improvements in
mortising machines, and having explained the manner of carrying the same into
practical effect, I wish to have it understood that I do not confine myself to the exact
details and configurations of the " toggle lever and link" nor the exact position of
the fulcrum and other centres of the same shewn in the Drawings, as the same may
obviously be varied without departure from the distinctive characteristics of my
Invention as hercin set forth; furthermore, I declare that I do not intend to claim
any of the mechanical parts shewn and described when taken separately and apart
from the combination or application thereof in manner and for the purpose herein
set forth; but what I consider to be novel and original, and therefore claim as
secured to me by the hercin-before in part recited Letters Patent is, the adaptation
to and use in a mortising machine of a toggle arrangement (elbow or knee joint)
operated by the hand lever for actuating the cutting tool as above set forth, and
whether the hand lever proper forms part of the said toggle arrangement or not.
In witness whereof, I, the said Thomas Edwin Craven, have hereunto set
my hand and seal, this Nineteenth day of July, in the year of our Lord
One thousand eight hundred and seventy-six.
THOMAS EDWIN CRAVEN. (LS.)