Improvements in or connected with Chain Mortising Machines.
Year: 1893

page_text: The decision of the Comptroller-General, of the 11th day of August 1894,
allowed, under Section 18 of the Patents, &c. Act, 1883, an Amendment
of this Specification.
Date of Application, 5th Aug., 1893-Accepted, 4th Nov.,
1893
COMPLETE SPECIFICATION (AMENDED).
Improvements in or connected with Chain Mortising Machines.
We, JOHN HENRY HALL, of 47 West Bank, Stamford Hill, in the County of
Middlesex, Agent, and DENIS PARRY, of 38 Spencer Road, Herne Hill, in the
County of Surrey, Engineer, do hereby declare the nature of the said invention and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accompanying two
sheets of drawings, and to the letters and figures marked thereon, that is to
say :-
These improvements relate more especially to the chain-mortising machinery for
which Letters Patent were granted to us dated the 15th day of June 1891
No. 10,120, but they are also more or less applicable to other chain-mortising
machinery.
One part of our improvements relates to the cutters employed in connection with
the chain. The chain cutter links, described in the Specification of the aforesaid
Patent, are formed of pieces of metal of channel section consisting of a table or
flat portion forming the cutter proper, and two parts standing at right angles
thereto the whole giving a cross section somewhat like two capital letters T placed
side by side with their heads joined together. The stems of these T's form the
double links of the chain, each double link being connected to the next by a single
link after the manner of certain kinds of ordinary pitch chains. Now according to
our present improvement we make the cutter link as shown in Figure 1 of the
drawings of a simple T section the head A of which forms the cutter, and the
stem B the single link of the chain, the adjacent links being double, that is one
placed at either side of the single link and connected thereto by pins in the usual
way, or single links C may be used as shown in Figure 2. These single links C
are formed with slots D at their ends into which the ends of the single cutter-links
are fitted and connected by pins. By these means we considerably reduce the cost,
and increase the strength of the chain, besides which there is greater clearance
space at A' in front of the cutter A for the escape of the material as fast as it is
cut away in the mortise than when the cutter link is formed of channel section; and
to further facilitate the escape of the said material we bevil the part of the link
at A¹ behind the edge of the cutter A so as to form a cutting edge as shown both
in Figures 1 and 2.
Another improvement in connection with the cutters consists in forming the face
of the link, which is in front of, or in advance of, the cutter-link, sufficiently high
to come nearly but not quite up to the level of the cutting edge of such cutter-link
so as to form a fence or guard, whereby the cutter is prevented from taking too
deep a cut into the wood; the said face of the link in advance of the cutter-link
acting after the manner of the mouth of a plane or the fence of a spoke-shave to
limit the thickness of the shaving removed. The requisite height of the fence or
guard on the face of the link may be obtained by suitably shaping the face of the

page_text: link itself as shown at E in Figure 3 or by rivetting or otherwise attaching a
suitable piece thereto as shown by way of example at E' in Figure 2, and it is
preferable to make these links of the full width of the cutters A so as to act as
guides to prevent the latter from swaying to either side.
Another part of our improvements relates to a spring guard which is made to
bear on the material to be mortised, at that end of the mortise where the chain
cutters emerge from the material; and its object is to hold down the fibres of the
wood at that point so as to prevent skelping, splintering or tearing up of the said
fibres by the emerging cutters. Figure 4 of the drawings is a front elevation of part
of the upper portion of a chain-mortising machine with the said spring guard fitted
thereto, and Figure 5 is a side view of same. The same parts are shown to a
smaller scale in Figures 6 and 7 which are respectively a front and side elevation
of a complete chain-mortising machine with our various improvements applied
thereto.
F is a bracket secured to or formed with the head of the machine and carrying
the bearing G for the shaft H of the sprocket wheel I which drives the cutter
chain J. K is a plate or disc adapted to swivel on the centre bolt K¹ but to be
secured in the required position to the part of the bracket F by a nut K³
screwed on to the end of such bolt. K³ are lugs on the plate or disc K through
which slides freely the tube L having at its lower end a foot L' to which is secured
the shoe L by means of a bolt and wing nut L. The shoe L' can be adjusted
towards or away from the cutter chain J by the bolt L³ sliding in a slot L' in the
shoe L'. M is a spindle secured at its lower end to the foot L. N is a spiral
spring which surrounds the spindle M and takes into the annular space between
the interior of the tube L and the exterior of the spindle M. This spring
bears at its lower end ou the foot L' and at its upper end against the underside
of a projecting part M¹ of the head of the machine. The upper end of the
spindle M passes into a slot in this part M¹ so that while the said part M'
serves as an abutment for the upper end of the spring N it leaves the spindle M
free to follow the movement, for purposes of adjustment, of the plate K and
tube L on the centre bolt K'. It will now be understood that as the piece of
timber P to be mortised is raised up by the treadle P¹ (seen in Figures 6 and 7) so
as to bring it under the action of the cutter chain J, the shoe L, foot L', tube L
and spindle M will be raised with it against the action of the spring N. When the
cutter chain J is arranged so as to make mortises with parallel ends, that is to say
mortises the length of which is the same at both sides of the timber, the tube L
and spindle M are adjusted by the plate K and bolt and nut K' K2 so as to be.
vertical and parallel with a line joining the centre of the sprocket wheel I and the
centre of the lower roller I', the front edges Lx of the shoe L' being adjusted to
coincide, or very nearly so, with the end of the mortise on the emerging side of the
cutter chain. Under these circumstances the front edge L* of the shoe L² will rise
with the timber and remain in the same position thereon preventing skelping or
splintering of the fibres at the end of the mortise by the emerging cutters. When
however the cutter chain J is arranged so as to make mortises with tapering ends,
that is to say mortises the length of which is greater on one side of the timber than
the other, and as will be hereinafter more fully referred to, the tube L and
spindle M are adjusted so as to stand parallel to the emerging side of the cutter-
chain as shown in Figures 4 and 6 so that as the timber P rises, moving the shoe L
upwards with it, the said shoe slides backward on the timber, giving place to the
more and more projecting emerging cutters, but continuing to hold down the fibres
close to the end of the mortise so as to prevent skelping splintering or tearing up
such fibres by the emerging cutters.
Another part of our improvements relates to means and appliances whereby-we
are enabled at a single operation In order to make the mortises wedge-shaped,
that is to say, longer at one side of the material than at the other side, so as to
afford room for the insertion of the usual wedges employed when gluing up the
work, For this purpose we make the chain guide Q (see Figures 4 and 6) which

page_text: is fixed rigidly to the bracket F by the bolt Q' and guides the chain J while
the latter is passing through the mortise, may be made of a tapering form as
shown. This tapered chain-guide is shown separate and to a larger scale in
Figures 8 and 9 which are respectively back and side elevations with the chain-
guide roller I at the lower end of the guide shown separately below each
figure. The length of the tapering portion of the chain-guide is adapted to
suit the depth to which the mortise is to be cut, and the width of such
tapering portion to suit the length of such mortise. We sometimes groove
the edges of this chain-guide Q as at Q in Figures 8 and 9, and also in a
corresponding manner the edge of the pulley or roller I¹ as shown at I³ in the same
figures, and of the sprocket wheel I as shown at I* in Figure 10 and we adapt the
links of the cutter chain or some of them with projecting parts R (as shown in
Figures 1, 2 and 4) to run in the said grooves whereby the chain is constrained to
follow the shape of the said chain-guide, and complete steadiness of motion of the
chain is thereby secured.
Another improvement relates to the means For the purpose of regulating the
tension of the cutter chain, and enabling it to be readily put on to or taken off
the sprocket or driving wheel, For this purpose we may mount the spindle H
carrying the sprocket wheel I in a block G which is free to slide up and
down in an opening G¹ in the part of the frame of the machine. Attached
to this block G is a screwed rod S which passes up through a hole in
the head T of the machine and is provided at its upper end, with a nut U
formed as a hand wheel or otherwise, by means of which the said block G
with the sprocket wheel I can be raised or lowered so as to either tighten the
chain J to the tension suited for working, by drawing it up more or less firmly
against the guide roller I at the lower end of the chain-guide Q; or to slacken it
to enable it to be removed from and replaced in the machine. The aforesaid nut U
may bear upon a pad V of indiarubber, or upon any other suitable spring to enable
the parts to yield sufficiently to avoid damage in case they are subjected to undue
strain in working. The spindle H of the sprocket wheel has fixed on it a spur
wheel H' that remains in gear with the spur wheel H' on the spindle of the driving
pulley H³, the movement of the block G not being in any case sufficient to take the
wheel Hout of gear with the wheel H³.
Heretofore so far as we are-aware it has been customary in many chain mortising
machines to regulate the tension of the cutter chain by moving the cutter-chain
guide to or from the sprocket wheel axis; but in the arrangements above described
we fix the cutter-chain guide Q in one position on the frame of the machine, and
effect, the regulation of the tension by moving the sprocket wheel axis H towards
or away from the said guide whereby we secure perfect steadiness and rigidity of
Buch guide while the cutter chain operating in the mortise.
In chain-mortising machines as heretofore constructed it is sometimes found
difficult to keep the bearing of the chain-guide roller I', at the lower end of the
chain-guide, properly lubricated. In order to facilitate the lubrication of this the
parts we may be arranged it as shown in Figures 4, 8 and 9, in which the bearing
for the roller is shaped as a fork I' at the lower end of the chain guide Q. The
branches of this fork pass into the groove I' of the roller I one on each side of the
axis I of such roller.
It will now be understood that lubricating material can easily be introduced
between the fork I and the roller I', and this may be further facilitated by
slackening the cutter chain by the means above described, so that the roller I' is
lowered somewhat in the fork 1' thus giving more room for the introduction of oil.
Similar letters of reference relate to like parts in all the figures of the drawings.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, we desire to have it understood
that we are aware that it is not novel to employ a spring-guard in wood working
machinery for the purpose of preventing the wood from splintering or tearing up under

page_text: the action of the cutters, and that we make no claim generally to the use of a spring-guard
for that purpose; also that we make no claim to the tapered chain-guide as described;
or to the means described for regulating the tension of the cutter-chain; or to the means
described for facilitating the lubrication of the chain-guide-roller, as we have found that
the same are not nonel, but we declare that what we do claim is :-
First. In a chain-mortising machine constructing the cutter links of the chain
of T section, substantially as described with reference to Figures 1 and 2 of the
drawings.
Second. In a chain-mortising machine, constructing the face of the link which
immediately precedes the cutter link with a fence or guard, substantially as
described with reference to Figures 2, 3 and 4 of the drawings and for the purpose
specified.
Third. In a chain mortising machine, the use of a spring guard arranged to
bear on the material to be mortised at that end of the mortise where the chain
cutters emerge from the material, the said spring guard being constructed and applied
substantially as described with reference to Figures 4, 5, 6 and 7 of the drawings
and for the purpose specified.
Fourth. In a chain mortising machine making the guide which guides the eatter
chain while the latter is passing through the mortise, of a tapering form for the
purpose of making mortises wedge shaped at a single operation, substantially as
described in reference to Figures 4, 6 and 8 of the drawings.
Fifth. In a chain mortising machine, the guide roller and the bearing for the
same at the lower end of the chain guide Q, constructed combined and operating
substantially as described in reference to Figures 4, 8 and 9 of the drawings.
Sixth. In a chain mortising machine the device for regulating the tension of the
catter chain, and for slackening such chain to enable it to be removed from
the machine at pleasure, which consists of the sliding block forming the bearing
for the sprocket wheel spindle adapted to be moved to and from the fixed outter
chain-guide by means of a screw and not provided with an elastic washer or spring,
substantially as described in reference to Figures 4, 5, 6 and 7 of the drawings.
DATED LAIKHLI OXY O
AUZUNE KOPPA
WALCO LOIX ALL OXY UL AUXIL O
J. H. HALL,
D. PARRY,
Per W. H. Beck,
115, Cannon Street, London, E.C., Agent.