Improvements in Marking or Cutting Instruments.
Year: 1888

page_text: Date of Application, 31st Oct., 1888
Specification Accepted, 31st Dec., 1888
Improvements in Marking or Cutting Instruments.
.
I, THOMAS SMITH of 16 Commercial Road, Southampton, in the County of Hants,
Carver and Gilder, 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 which are applicable to a large variety of
instruments in which a marking or cutting point or edge requires to occupy a certain
relative position or bear a certain relation to the direction of the mark or cut to be
made. Among such instruments as examples may be mentioned a drawing pen, a
knife to be used for cutting veneer and a glass marker or cutter. To the last of those
examples my invention is especially applicable and for the purpose of rendering a
clear explanation of my invention I will confine my description to its application to
such an instrument.
Hitherto the construction of glass markers or cutters or what are more generally
known as glaziers' diamonds has been such that unless used by those well accustomed
to them the results have often been far from satisfactory and often attended by
breakage. Among the causes to which these failures may be attributed are first:
the uneven pressure with which the diamond is applied to the glass which unevenness
is sometimes due to the length of the cut, the operator at arm's length unconsciously
bearing on the cutter with less pressure than when he has it nearer to him and conse-
quently exercises greater leverage upon it, and secondly-where curved or crooked
cuts are made the diamond has not been properly directed towards the lines of such
cuts. By my present invention I entirely overcome these difficulties and it will be
seen from what is herein explained that a person without any previous glass-cutting
experience whatever with one of my glass cutters could not fail on either of the
before-mentioned grounds to satisfactorily secure either a straight or crooked or
curved cut.
In the accompanying drawings Fig. 1 is an elevation and fig. 2 a longitudinal
section of a glass cutter constructed according to my invention and figs. 3 and 4 are
respectively a longitudinal section and an inverted plan drawn to an enlarged scale of a

page_text: detached portion of the same figs. 5 and 6 are views illustrative of the construction
of part of the same and fig. 7 is a side elevation of the diamond and dise in
which it is mounted fig. 8 is a section of the lower part of a modified form of the said
cutter.
Like letters indicate like parts throughout the drawings.
A is a tube or handle closed at one end by the plug A' and formed at its other end
with the partly spherical cup A. B is a partly spherical bulb formed in part with
the case B¹ and constituting with the cup A2 into which it fits, a universal joint. B² is
a tube secured to or formed in part with the bulb B and the upper end of which is
screw-threaded to receive the plug B³. C is the diamond which as shown clearly in
fig. 4, is set eccentrically in the disc C in the centre of which is secured the lower
end of the spindle C² whose upper end is reduced to a centre point as shown clearly
in fig. 7. D is a small inverted-cup-shaped piston or plunger capable of sliding
freely in the tube B2 and the recess of which bears upon the upper pointed end of the
spindle C².
D' is a spiral spring which exerts its pressure between the plug B³ and
the piston D in such manner as tends to push the disc C and diamond Cout from
the case B in which however it is prevented from being pushed out beyond the
required limit by the flange D² of the disc C¹ which, when such limit is reached rests
on the flange B of the case B.
In the arrangement shown in fig. 8 the diamond C is mounted in a rimmed disc C¹
in a manner similar to that herein before described but in this construction a curved
flat spring D³ is secured to its back the upper end of this spring' is secured to the
spindle the upper end of which terminates in a centro point and has its bearing in
the underside of the plug B³ which can be moved to adjust the pressure of the
spring D³. The lower part of the tube B2 may guide the spindle in the manner
shown.
Although I do not bind myself to any particular way of constructing the before-
described glass cutters yet I find it convenient to make them in the manner shown in
the accompanying drawings figs. 5 and 6. illustrating the means I preferably adopt
for connecting the bulb B with the cup A2 which as shown in fig. 5 before
receiving the bulb B is of partly parallel bore and which after the bulb is in
position, is turned over in the manner shown in figs. and 6 so as to retain tho said
bulb.
To use the cutter it is grasped by the handle A and its lower end is pressed down
upon the glass and it is then drawn in the direction required. By so pressing the
instrument downwards the lower edge or flange B of the case B' will have come into
contact with the glass and no matter what further pressure the operator may apply
the diamond will bear upon the said glass with only such strength as the spring D¹
or D³ is capable of exerting upon it, thus preventing the often disappointing results
hitherto incurred by at-one-time pressing upon the cutter with a greater power than
at another time. Supposing that when the cutter was pressed upon the glass the
position of the diamond did not bear the proper relation to the direction of the cut to
be made for instance let it be supposed that it or an imaginary radial line passing
through it and the axis of the spindle C was at right angles to the direction of the
cut intended to be made, immediately the instrument was drawn along, the diamond
after the manner of the wheel or runner of a caster would turn round until the before
mentioned imaginary radial line was in line with the direction in which the instru-
ment was moved and would always thus adjust itself to any deviation from a straight
path. Supposing also that when so applied to the glass the handle A was not held
perpendicular to its surface any such alteration as might be necessary would be
provided for by the joint A³ B.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
.
1. The combination with the handle A of a spindle such as Cupon which the
cutter or marking point is mounted eccentrically substantially as herein described.

page_text: 2. In a marking or cutting instrument the combination with a handle such as A
and spindle such as C of a spring for exerting upon the marking or cutting
point a pressure independent of that applied to the handle substantially as herein
described.
3. In a marking or cutting instrument a handle formed in two parts united
together by a universal joint substantially as and for the purpose herein described.
4. The general arrangement and combination of parts constituting the complete
glass marker or cutter substantially as herein described and illustrated in the
accompanying drawings.