Year: 1887

page_text: Date of Application, 11th June, 1887
Complete Left, 12th Mar., 1888
Complete Accepted, 11th May, 1858
I, ROBERT LOW, of the Royal Laboratory, Woolwich Arsenal, in the County of
Kent, Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to dovetailing-machines wherein two rotating discs are
arranged with their axes inclined relatively to each other and to the axis of the main
or driving shaft, and are provided with saw-blades which extend to thirds around
their peripheries.
My said invention is chiefly designed to improve the construction and increase the
efficiency of the machines known as Armstrong's dovetailing-machines. In these
machines as heretofore constructed, there is no provision for varying the width or
pitch of the dovetails. Moreover, the mechanism for feeding the boards to bo dove-
tailed operates continuously; it has, therefore, been necessary to employ helical or
spiral saw-blades of a pitch corresponding to the distance through which a board is
moved in each revolution of the discs.
An important feature of my said invention is the construction of a dovetailing-
machine of this kind or class in such a manner that, by a simple adjustment of some
of the parts and the requisite alteration of the feed, the said machine may be adapted
for cutting dovetails differing in either width or pitch or in both width and pitch.
Another feature of my said invention is the employment of feed-mechanism which
operates intermittently, so that I am enabled to dispense with the helical or spiral
saw-blades heretofore used and to employ flat circular blades.
My said invention, moreover, comprises various other improvements hereinafter set
forth.
In carrying my said invention into practice, I provide a suitable bed-plate or
frame having formed thereon or attached thereto suitable bearings in which is
supported the main or driving shaft. The saw-discs are placed upon this shaft and
aro supported in suitable bearings so that their axes are at an angle or inclination
to each other and to the axis of the said shaft. The said discs are connected with
the driving shaft by universal joints, so that they will rotate with the said shaft
notwithstanding the inclination of their axes. For this purpose I prefer to fix on
the said shaft a spherical piece of steel provided with grooves which extend length-
wise of the shaft. The hub of the disc is provided with a suitable bush and is fitted
to rotate upon the said spherical piece. Keys are inserted in the hub of the said
dise and fit into the said grooves so that, in the rotation of the disc, the said keys
will move to and fro in the said grooves.

page_text: In Armstrong's machines as heretofore constructed, each disc is driven by means
of separate gearing whereby it is connected with a separate driving shaft. It will
be seen, however, from the foregoing description that I connect the said discs
directly with a single driving shaft. I am thus enabled to dispense with the said
gearing.
In my improved machine, each saw-blade is mado up of sections or segments
substantially as in Armstrong's machine, with the exception that the said segments
are all in the same plane instead of being arranged as heretofore in the form of a
helix, and the said blade extends only partially around the periphery of the disc, so
that the said disc can be continuously rotated without interfering with the feeding of
the boards to be dovetailed.
The bearings for the discs are supported in heads or brackets secured to the bed plate
or frame of the machine. Either or both of these heads are made adjustable to
regulate the distance between the saw-cuts, according to the desired width of the
dovetails.
I prefer that the bearings for the said discs should be supported in arms which are
capable of being turned upon or about the axis of the driving shaft, so that the
angle or inclination of the discs may be varied. These arms are connected with the
said heads or brackets and are provided with toothed segments which are geared
with pinions whereby the rotary adjustment of the said arms and bearings may be
effected. By theso means I am enabled to readily adapt the machine for forming
either the pins or tenons or the mortises of dovetails.
The feed-mechanism comprises right and left hand screws as heretofore. One of
these screws is, however, arranged to be intermittently instead of continuously rotated.
For this purpose, I usually employ ratchet-and-pawl mechanism operated by means
of a lever and a cam fixed on the main or driving shaft. The said ratchet-and-
pawl mechanism is connected with the said screw by means of suitable gear-wheels.
To provide for varying the pitch of the dovetails, I employ change-wheels similar
to those used in screw-cutting lathes. Or I make the ratchet-and-pawl mechanism
adjustable so that I can vary the length of stroke or travel of the pawl.
It is obvious that I may employ other means for imparting interinittent motion to
the said feed-screw, and for regulating the feed-movement to vary the pitch of the
dovetails.
According to a modification of my said invention, 1 form or fix toothed rings on
the discs and gear them with bevel-wheels keyed upon the driving shaft. In this
case, each of the discs is fitted to rotate upon a bearing or supporting piece formed
on a bush or sleeve in which the driving shaft is fitted to rotate, and which is fitted
so that it is capable of rotary adjustment in a bracket or upright secured to the bed-
plate or frame of the machine. The said bearing or supporting piece is so formed
that it is at an angle or inclination to the axis of the driving shaft. A toothed
segment is fixed upon the said bush or sleeve and is geared with a pinion whereby
the rotary adjustment of the said bush or sleeve and of the bearing or supporting
piece may be effected. The bevel-wheel geared with the disc which is carried by the
adjustable head or bracket must be so connected with the driving shaft and with the
corresponding bush or sleeve that it will be adjusted simultaneously with the said
head or bracket, and the disc, and will always maintain its proper position relatively
to the said disc.
My improved machine affords considerable advantages over those now in use, the
chief advantage being that dovetails of different width and pitch can be cut by the
same machine.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
1.

page_text: I, ROBERT LOW, of The Royal Laboratory, Woolwich Arsenal, in the County of
Kent, 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 :-
My invention relates to dove-tailing machines and is chiefly designed to improve
the construction and increase the efficiency of machines such as that known as
Armstrong's dove-tailing machine."
In these machines as heretofore constructed, there is no provision for varying
the width or the pitch of the dovetails. Moreover, as the mechanism for feeding
the boards to be dovetailed operates continuously, it has been necessary to employ
helical or spiral saw-blades of a pitch corresponding to the distance through which
a board has to be moved in each revolution of the said blades.
An important feature of my said invention is the construction of a dove-tailing
machine of this kind or class in such a manner that, by a simple adjustment or
alteration of the feed mechanisın, the said machine may be adapted for cutting dove-
tails of different pitch.
Another feature of my said invention is the provision of means for adjusting one
or both of the saws to vary the width of the dovetails, so that dovetails of different
width may be cut by the same machine.
Another feature of my said invention is the employment of feed-mechanism which
operates intermittently, so that I am enabled to dispense with the helical or spiral
saw blades heretofore used and to employ flat circular or plane disc saw-blades.
Moreover in Armstrong's machine as hitherto constructed, the discs carrying the
saw-blades are each connected by gearing with a separate driving shaft. According
to my invention, however, I connect the said discs with a single driving shaft, and
if desired, to dispense with gearing between the said discs and the shaft.
In the accompanying drawings I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a front elevation;
Figure 2 a side elevation; and
Figure 3 a plan, partly in horizontal section, of one form of my improved dove-
tailing machine.
Figure 4 is a transverse section on the line x, x, Figure 1.
Figure 5 is a longitudinal central section drawn to an enlarged scale, the frame
and other parts being removed, and,
Figure 6 is a section on the line x²x² Figure 5, shewing the mechanism in
another position.
Figure 7 is a transverse section, and
Figure 8 a longitudinal central section, also drawn to an enlarged scale, showing
a modification of my said invention.
Like letters indicate corresponding parts throughout the drawings.

page_text: A is the frame of the machine, B is the driving shaft, which is supported in
bearings C. D, D are the discs carrying the saw-blades D¹.
Referring to Figures 1 to 6, the saw-discs D are placed upon the shaft B and
supported in suitable bearings a in brackets hereinafter described, so that their axes
are at an angle or inclination to each other and to the axis of the said shaft. The
said discs D are connected with the driving shaft B by universal joints so that they
will rotate with the said shaft notwithstanding the inclination of their axes. For this
purpose I fix on the said shaft B spherical pieces b. These spherical pieces are
keyed upon the said shaft by means of keys c of steel or other suitable metal fitting
in key-ways c; keys d are, moreover, fitted in grooves d¹ in the said spherical
pieces extending lengthwise of the shaft, and are provided with gudgeons d² fitting
into corresponding holes in the bosses or hubs e of the discs D, and in suitable
bushes fixed in the said hubs by means of screw-threads at g. The said keys d
are fitted to move to and fro in the grooves d' upon the said spherical pieces 6 when
the discs are rotated. The key e inserted in one of the said spherical pieces b to fix
the same upon the shaft B is provided with a long groove or key-way, and is so
arranged as to permit adjustment of the said disc for the purpose of varying the
distance between the saw-cuts forming the mortises or pins of the dovetails."
The bearings a of the discs D are supported in heads or brackets / h* secured to
the frame A of the machine. The head or bracket h is made adjustable to regulate
the distance between the saw-cuts according to the desired width of the mortises or
pins of the dovetails. If desired both of the brackets and discs are made adjustable
for this purpose.
I prefer that the heads or brackets h, h* carrying the bearings a for the said
discs D should either be attached to, or form part of arms h. The said arms h¹ are
supported upon sleeves or bushes & bolted or otherwise attached to the frame A, and
are therefore capable of being turned upon or about the axis of the driving shaft B,
so that the angle or inclination of the discs D may be varied. The said arms are
provided with toothed segments ; which are geared with pinions whereby the
rotary adjustment of the said arms and heads or brackets * may be effected.
By these means I am enabled to readily adapt the machine for forming either the
pins or tenons or the mortises of dovetails.
Figures 5 and 6 represent the heads or brackets h h* in the reverse position for
cutting the pins or tenons of the dovetails.
The feed-mechanism comprises a right hand screw and a left hand screw as
heretofore. The screw is, however, arranged to be intermittently instead of
continuously rotated to permit the action of the plane disc saws.
For this purpose,
I usually employ a ratchet-wheel m actuated by a pawl n pivoted at n¹ to a lever o.
The said lever o is pivoted at o¹ and is connected, by means of a rod p and joint-pins
p, p, to another lever q pivoted at q¹ and provided with a friction roller running
in a groove s¹ in a cam s fixed on the main or driving shaft B. The said ratchet-
wheelm is connected with the screw by means of suitable gear wheels t, t¹, t².
9
To provide for varying the pitch of the dovetails, I employ change-wheels similar
to those used in screw-cutting lathes. Or I make the above described ratchet-and-
pawl mechanism adjustable so that 1 can vary the length of stroke or travel of the
pawl n. For this purpose I lengthen the lever q and provide suitable means whereby
the distance between the joint-pin p2 and the roller can be altered so as to vary the
throw of the pawl n.
According to another modification of my said invention, I form or fix toothed
rings on the discs and gear them with bevel-wheels fixed upon the driving
shaft B by keys ¹. In this case the discs D are fitted to rotate upon bearings or
supporting pieces w having bushes or sleeves w₁ rigidly fixed in the same, in which
the driving shaft B is fitted to rotate. The said supporting pieces w are fitted in
brackets attached by means of screws or bolts a¹ to the frame of the machine. The
said supporting pieces w are capable of rotary adjustment in the said brackets & by
means of set-screws y. The said bearing or supporting pieces w are so formed that.
they are at an angle or inclination to the axis of the driving shaft B. Toothed segments z

page_text: で
are fixed upon the said bushes or sleeves w¹ and are geared with pinions whereby the
rotary adjustment of the said bushes or sleeves wand the bearing or supporting
pieces w may be effected. The bevel-wheels geared with the toothed rings u upon the
discs D, which are carried by the adjustable bearing or supporting pieces w, must
be so connected with the driving shaft B and with the corresponding bushes or
sleeves that they will be adjusted simultaneously with the said bearing or
supporting pieces to and the discs D, and will always maintain their proper position
relatively to the said discs D.
It will be readily seen that my improved machine affords considerable advantages
over those now in use, the chief advantage being, that dovetails of different width
and pitch can be cut by the same machine.
Moreover it is obvious that I can somewhat further modify the construction of my
improved machine without departing from the nature of my said invention. For
instance I can provide other means than those above described for imparting
intermittent motion to the said feed-screw 1, or for regulating the feed-movement
to vary the pitch of the mortises or pins of the dovetails.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I wish it understood that I
claim
First. A dovetailing machine of the kind or class herein before referred to, wherein
provision is made for the adjustment or alteration of the feed-mechanism to vary the
pitch of the dovetails.
Second. A dovetailing machine wherein provision is made for the adjustment of
one or both of the saws to vary the width of the dovetails.
Third. A dovetailing machine provided with flat circular or plane disc saws and
with intermittently operating feed-mechanism, substantially as, and for the purposes,
set forth.
Fourth. A dovetailing machine wherein the saws are mounted upon a central shaft
and are driven by the said shaft, with or without the intervention of gearing, sub.
stantially as hereinbefore described.
Fifth. The improved machine consisting of the parts constructed and combined
substantially as described with reference to Figures to 6 or to Figures 7 and 8 of
the accompanying drawings and operating as, and for the purposes, above specified.
Dated this 12th day of March 1800.
Dated this 12th day of March 1800.
ROBERT LOW.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.