A Slate Slotting Machine.
Year: 1894

page_text: Date of Application, 31st July, 1894
Complete Specification Left, 23rd Apr., 1895-Accepted, 24th May, 1895
PROVISIONAL SPECIFICATION.
A Slate Slotting Machine.
I, FREDERIC KNIGHTS, of 10 Bolt Court, Fleet Street, London, E.C.,
Engraver, do hereby declare the nature of this invention to be as follows:-
-
This invention relates to a slotting machine designed for producing simultaneously
upon each side of a slate the slots required for the purposes of the invention
described in the Specification to my Patent No. 8283 of 1894.
According to this invention the slate to be slotted is laid upon a suitable bed-
plate and held securely between adjustable clamps travelling on a screw spindle one
half of which is provided with a right handed, and the other half with a left handed
screw thread, whereby, upon the rotation of the spindle, the clamps will be caused
to approach towards or to recede from each other.
Above the bed plate are mounted a pair of revolving cutters for forming the
slots, said cutters being rotated in opposite directions by a worm shaft mounted in
suitable bearings and engaging with worm wheels on the axes of said cutters, the
worm upon one portion of the shaft being right handed, and upon the other portion,
left handed. Each revolving cutter is carried in a suitable frame which travels
upon a screw spindle, constructed, like the screw spindle for operating the clamps,
with right and left handed screw threads. The cutters will thus be caused to
simultaneously approach towards or recede from each other when the said spindle
is revolved, which may be effected by suitable gearing from a first motion shaft
from which latter the before mentioned worm shaft would also be rotated.
The slate in which the slots are to be cut is placed between the clamps and
gripped thereby, and the cutters (previously separated so as to be clear of the
slate) are caused by rotating the first notion shaft, to approach the slate from each
side and to cut the slots therein simultaneously to any depth inwards required.
The simultaneous cutting of the slots on each side of the slate is effected by
disposing the cutters and the clamps upon either side of a centre line common to
both.
Dated this 21st day of July 1894
COMPLETE SPECIFICATION.
A Slate Slotting Machine.
1, FREDERIC KNIGHTS, of 10 Bolt Court, Fleet Street, London, E.C.,
Engraver, 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 a slate slotting machine for simultaneously cutting in

page_text: each side of a slate the dovetail slots required for the purposes of the invention
described in the Specification to my Patent No. 8283 of 1894.
I will now proceed to describe my invention and the manner of performing the
same having reference to the accompanying drawings, in which Fig. 1 is a front
elevation of the machine, and Fig. 2 is a detached plan view of the bedplate
thereof. Similar letters refer to corresponding parts in both figures.
a is the bed plate of the machine which is supported upon a suitable frame or
standards b. Above the bed plate a there are mounted, upon the guides c, the tool
boxes d, which carry each a revolving cutter shaft d terminating in a cutting
tool of suitable shape for producing the dovetail slots required. Each
tool box is traversed by the screw spindle e which is supported in suitable
bearings in the frame b and has right and left handed screw threads of
similar pitch formed thereon, the right handed thread operating one tool
box and the left handed thread operating the other, consequently, when the screw
spindle e is revolved, the tool boxes d will be caused to simultaneously approach
towards or recede from one another at equal speed. Upon the bed plate a are
disposed the clamps for gripping the sides of the slate to be operated upon, each
clamp being formed with a dependent lug which enters a slot a¹ in the said
bed plate and is traversed by the screw spindle f, formed, like the screw spindle e,
with right and left handed screw threads, the right handed thread operating one
clamp and the left handed thread operating the other. 13 is a hand wheel on the
end of the spindle, whereby the latter is rotated and the clamps fare caused to
approach towards or recede from one another simultaneously at equal speed. The
centre line 1-2 of the pair of clamps is arranged coincident with the centre
line 1-2 of the pair of cutters d, for the purpose hereinafter set forth. is a
shaft supported at each end in convenient bearings and carrying bevel wheels g
which rotate therewith and are free to slide longitudinally thereon; this may be
eflected in any convenient manner, as by providing a slot or groove g³ in the shaft g
with which slot engage feathers or projections formed within the bosses g of the
bevel wheels g². The said bevel wheels gear with the bevel pinions d³ on the
cutter shafts d', and are maintained in gear therewith during the movement of
the tool boxes along the guides by the forked arms secured to the said tool
boxes, the forked extremities of which arms engage with grooves formed around
the bosses of the bevel wheels g². In my Provisional Specification I have
described the cutter shafts d' as rotated by a worm and worm wheels, but I find the
arrangement illustrated in the drawings and above set forth to answer better in
practice. is the first motion shaft which revolves in the bracket bearing h' and
carries at one end the fly wheel and at the other end the bevel pinion which
gears with the bevel pinion on the vertical shaft carried in the bearings
formed on a convenient bracket secured to the frame b of the machine. The said
shaft carries at its upper end the bevel pinion which gears with the bevel
pinion on the shaft g at the extremity of which latter there is secured a spur
piniou k, which, through the pinion A, drives a spur wheel 2 on the extremity of
the tool box spindle e. From the above description and from the drawings it will
be seen that on rotating the fly wheel h² the cutters will be rotated in opposite
directions and the tool boxes d caused at the same time to simultaneously approach
towards or recede from one another, according to the direction of motion of the
fly wheel /².
Duts m³.
The slate to be slotted is laid upon the bed plate a, the cutters having
previously been moved apart so as to be clear thereof, and the distance of the slots
from the end of the slate is determined by adjusting the end clamps m by the thumb
The hand wheel is then rotated so as to cause the clamps to firmly
grip the slate upon each side, and as the cutters and clamps are, as before
mentioned, arranged upon either side of a centre line common to them both, the act
of gripping the slate between the said clamps automatically centres the former
between the cutters, which latter, when rotated and caused to approach each other

page_text: by revolving the fly wheel h², will commence to cut the slots upon each side of the
slate simultaneously and in perfect register.
Having now particularly described and ascertained the nature of the said inven-
tion and the manner in which the same is to be performed I declare that what I
claim is :-
1. The general construction, arrangement and combination of parts, constituting
a slate slotting machine, substantially as described and illustrated.
2. In a slate slotting machine, the combination of a pair of revolving cutters
carried by sliding tool boxes traversed by a screw spindle formed with right and
left handed screw threads of similar pitch, with a pair of adjustable clamps for
gripping the sides of the slate, said clamps being also traversed by a screw spindle
formed with right and left handed screw threads of similar pitch, the clamps and
the cutters being arranged upon either side of a centre line common to them both,
so that the act of clamping the slate automatically centres the same between the
cutters whereby the latter are caused to simultaneously commence the cutting
operation upon each side of the slate, substantially as described and illustrated.
Dated this 23rd day of April 1895
E. P. ALEXANDER & SON,
Chartered Patent Agents,
19, Southampton Buildings, Chancery Lane, London, W.C., Agents.