Year: 1885

page_text: 2
Fig. 4 is a plan. It represents Parallels showing the same closed & opened;
m. m. are bars laid in grooves or openings with joints so as to work same.
Fig. 5. is a plan. It represents Proportional Compasses (not divided now but can
be) showing same closed & opened. n, n, n, n are metal points added to arms &
fitted in joints (moveable).
No 2 DRAWINGS.
Fig. 1. is a plan. a, b, c, d e, f, g, h&i are the same as described for Nº 1 drawing.
jis a T or other section as arm (moveable) metal or other material as per enlarged
section, (Fig. 4). k is a moveable screw & plates. is a metal plate elongated if
required to adjust blade to, (Fig. 3). m is a set square with adjustable arm.
a moveable screw with protractor at joint as (Fig. 7.).
n is
Fig. 2 is a plan. It represent the above in another position without set square
& part of clamp.
Fig. 3 is a plan. It represents the above converted into a Centrolinead; jis an
open arm.
Fig. 4 shows a cross & horizontal section at f, the plate having a cut thro same.
Fig. 5 shows an alternate sections (enlarged) at f.
Fig. 6. is a plan showing joint & bar at m.
Fig. 7. is an enlarged section of crosspiece of T square (N° 1 & 2 drawings);
b, d, e, h, i, j apply as before stated; o is a metal or other material to form pin;
p shows part of board.
t

page_text: Improvements in Drawing and Angle Measuring Instruments
and Appliances.
I, GEORGE AYLING BARNARD, of Bixley House, Tower Street, Winchester Hamp-
shire, Architect. and Surveyors Assistant, 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 improved constructions of T squares, set squares and
drawing board clamps and to combinations hereof with each other whereby they
are rendered applicable to other purposes as will be hereinafter described.
My invention will be readily understood on reference to the accompanying
drawings, in which Fig. 1 shews a plan of a T square with set square and clamp..
The blade a of the T square is for the sake of portability, made in two separate
lengths that are "fitted together by a metal tongue piece f, rivetted or screwed on
to the one part and sliding with bevilled edges into an undercut groove on the
other part, as shewn more clearly in the longitudinal and cross sections at Figs. 8
and 9. The tongue fis let flush into the one part of a, and the groove of the
other is strengthened by a metal lining piece h, secured by rivets; the outer end of
this lining is also bevilled off and fits into an under cut edge g on the underside of
the tongue, so that the two parts are very securely held. If required the plate f
may be provided with a spring catch on its underside, that would spring into a
notch or hole in the groove into which it is slid.
The blade a is secured to the T head b by means of a screwed pin c passing
through the blade and screwed into a nut c¹ sunk into the underside of the T-head
as shewn more clearly in the enlarged section at Fig. 4, so that on loosening the
screw, the blade a may be shifted to assume any desired angle relatively to the
T head as shown at Fig. 2. The screwed pin might also be fixed in the T head
and project up through the blade, to receive a thumb nut above the latter. In
order to enable the blade a to be set accurately to any desired angle, a protractor
or semi-scale o of metal or other suitable material whose centre coincides with the
centre of the screw pin c, is let into the T head, and the end of the blade is provided
with a metal plate d formed as an index that can be set to any desired division on
the scale. This arrangement may be rendered more complete by enlarging the
middle part of the T head so as to obtain a protractor of larger size, which may be
provided with a vernier, for accurate adjustment of the angle. The protractor may
also be fixed in any other desired position relatively to the blade for indicating the
angular positions thereof, and may be of any length. Also, in place of using a
curved protractor, a protractor scale might be formed along the edge of the T head,
for the edge of the blade to work against. The T head 6 has fixed to its working
face a metal angular bar 'm one part of which projects a small distance in front of
the said face, and the clamps g of the drawing board has a metal edge plate s fixed
to it, the clamp q being grooved behind the edge so that the bar m can overlap the
edge 8 and fit into the said groove as shewn at Fig. 4, whereby the-T square will
be held securely against the drawing board. Should this not be desired, the T head

page_text: can be used equally well with the face of the bar working against the face of the
edge plate 8. The clamp of the drawing board is made of T shaped section as
shewn, fitting into a groove in the board and secured by dowel pins in the
latter passing through slotted holes in the clamp. It will be evident that the
metal bar m may be extended so as to form a facing to the entire T head.
The T head is also provided with a metal bar i, fitting into a groove in its back
edge, and pivotted to it by a pin at , so that it can be raised out of its groove and
brought into an angular position such as shewn at Figs. 3 and 5. When the bar
is required to be thus used, it is secured in position by means of a metal plate u
which is attached to the T head by means of a screw screwing into a plate h
fixed on the end of the T head, and by a tongue r fitting into a slot in the back of
the head and secured, if necessary, by a screw.
.
The plate u has a circular slot through which passes a thumb screw p, which
also passes through the bar and is secured by a nut below. Thus the bar i will
be held securely in any desired angular position. The above described construction
of the parts will be clearly understood on reference to the enlarged plan at Fig. 5,
and the sections, taken respectively on lines A A and B B and Figs. 6 and 7.
The T head has formed near its one end a groove or slot, covered by a slotted
metal plate, in which groove is a movable screw nut n, so that on disconnecting.
the blade a from the central nut c¹ and connecting it by the screw c to the nut n
in the slot, the T square may be converted into a centrolinead by securing the
T head and the bar in the requisite angular positions relative to the edge of the
blade. The adjustability of the nut in the groove is necessary in order to enable
the edge of the blade a to be brought accurately in line with the apex of the angle
formed by the outer edges of the T head and the bar i. In order to enable the
T square to be adapted as a centrolinead either for left hand or right hand use,
the groove in the T head may be formed right through the same, and the nut made
to slide between two slotted plates, one on each side, so that the position of the
T head and bar can be reversed relatively to the blade a. It will be evident that
the parts just described as applied to the one end of the T head, might be duplicated
at the other end.
i The edges of the T head and bar i work in the usual manner against pins fixed
on the board, as indicated at x x Fig. 3. If a greater range is required than is
afforded by the length of the T head and bar i, these may be provided with
extensions 8 8¹, as shewn in dotted lines at Fig. 3, secured by pins 8' on the one
part fitting into holes and notches in the other, or secured as will be described
with reference to the next modification.
Fig. 1 shews at t my improved set square with adjustable angle, Fig. 10 shews
an enlarged plan of the end thereof and Figs. 11 and 12 shew sections taken
respectively on lines C C and D D. The set square t has fixed to its end a metal
prece z, to which is pivotted the metal bar u³ turning on a pin at a¹ and having fixed
to it a slotted quadrant or semicircular guide w, which works over the upper face
of the set square, while the bar u¹ works flush with the underface thereof, as
shewn at Fig. 12. A screw y, screwing into the set square passes through the slot
of the guide and has a thumb head on its upper end, by means of which the
guide wis secured in whatever angular position the bar u¹ is made to assume.
'
The quadrant guide is marked with degrees for adjusting the bar u¹ accurately
to any desired angle. The quadrant guide is secured to the bar u¹ by means of
à thumb screw screwing into a block fixed on the bar.
Fig. 1 sheet II shews a plan of another modification of the above described
T square. In this case the two parts of the blade are secured together by a
plate frivetted to the one part and secured to the other by means of screws g¹
with flat heads having holes to receive a key and screwing into nuts' fixed in the
other part and projecting up through holes in the plate as shewn more clearly in
the enlarged sections at Figs. 8 and 9. .The plate f has an undercut edge g, against
which fits the bevilled edge of the other part of the blade, so as to hold the two
parts securely together. The joint may also be formed by inserting the connecting

page_text: plate into a slot in the blades, as shewn in the longitudinal section at Fig. 10,
instead of fixing it on the surface thereof; in this case the, nuts are not fixed
in the blade but are removable. Fig. 11 shews sections thereof at right angles
to each other; either the flange or the boss must in this case 'be made of
a shape that will not turn round. The mode of securing the blade to the
T head and the construction and connections of the latter are mainly the same
as in the previous arrangement and the corresponding parts are indicated by
the same letters of reference. The metal bar i has in this case a bar of wood
or other material is attached to it, as shewn more clearly in the enlarged section
at Fig. 4 which can serve for the reception of sights. 11, of any suitable known
construction as shewn at Fig. 16, so that when the T head is detached from the
blade and is stood on edge as shewn, the bar i may be used for measuring angles.
The plate u, constructed as before, is for this application provided with a scale of
degrees, and the T head has also a spirit level let into it at 2, for adjusting its
horizontal position.
Fig. 2 shews the T square with the blade in an angular position, and Fig. 3
shews it, adapted as a centrolinead in the same manner as before described. Fig. 12
shews a section to an enlarged scale indicating the manner of fixing the extension
bars to the bar i, this being effected by a screw j passing through i and screwing
into a nut on 8, which also has a stud which fits into a slot q in the end of i.
Fig. 13 shews a cross section through this connection, Fig. 14 a section through
the nut at j and Fig. 15 shews a plan. Fig. 5 shews an enlarged plan of the end
of the T head and bar i with plate u and connections, these being the same as
previously described, and Figs. 6 and. 7 shew sections respectively on lines E E
and F F.
"
Figs. 1 to 11 on sheet III shew another modification of my above described
Tsquare and set.square, wherein the set square is also adapted firstly to form the
arms of the centrelinead, instead of employing the T head for this purpose,
secondly to form a parallel ruler, and thirdly to form proportional compasses.
Fig. 1 shews a plan of the T square and set square, Fig. 2 shews the same
with the blade adjusted to any desired angle, Fig. 4 shews an enlarged section of
the blade and T head. In this construction the securing of the blade a in its
angular positions is further insured by a second setting screw c³, screwing into a
nut that can slide in a semicircular groove in the T head, such groove being
covered by a metal plate having a semicircular slot for holding in the nut. Thus
when the blade has been adjusted to the required angular position round the
screw c, the screw c being at the time loosened, it is then securely fixed in that
position by tightening that screw.
The T head may, in addition to the angle rail m described with reference to
sheet I, be provided with a metal plate m¹ fixed to its working face, as shewn
at Fig. 4.
The set square in this construction consists of two bars n n, pivotted together
at n¹, where they are provided with a compass-joint secured by a screwed pin 8
and to the one part is secured a quadrant plate n¹ by means of the screw s and a
second screw 81, this plate being marked with a protractor scale, so that the said
part n can be set accurately to any desired angle relatively to the other part.
For securing the two parts in the angular position, they each have a longitudinal
slot in which slide nuts as shewn in the section Fig. 11 and a slotted bar g is
secured to these nuts by screws, so that when the one part n is raised into the
angular position, as shewn in dotted lines Fig. 1 it is securely held therein by the
bar g.
On separating the two parts n n from each other by removing the screwed pin
from the hinge-joint and detaching also the quadrant plate n², they may be
converted into a parallel ruler as indicated at Fig. 8, by connecting them together
with bars h h pivotted by screwed pins to nuts in the slots. As the parts n n
may be converted into proportional compasses as shewn at Figs. 9 and 10 by
forming slots 2 in the ends thereof into which are fitted points r, secured if

page_text: -
necessary by setting screws, the two bars being in this case pivotted together by
a screwed pin u passing through sliding nuts in the slots of both parts and secured
by a nut. The one bar is for this purpose marked with divisions such as those
generally used for proportional compasses. It will be evident that this set square
may also be used as a sector by forming the ordinary sector scales thereon; also":
that the slots therein may be dispensed with when it is not to be used for the
other purposes.
The set square n n may also be employed for forming in combination with
the blade a of the T square and a plate v, a centrolinead as shewn at Fig. 3, and,
to an enlarged scale at Figs. 5, 6, and 7. In this case the set square is secured by
the screwed pin's of its hinge-joint to the plate v, the one bar n being also secured
to the plate by a screw w, passing through its slot and screwing into the plate or
into a nut thereon, or w may be a stud fixed on the plate v and passing into the
slot, the other bar n is secured by a screw wl passing through its slot and through
circular slots in the plate v, and fixed by a thumb nut, so that this bar can be
turned on the joint s into any desired angular position relative to the other bar
and be then secured by the screw w¹. The blade a is attached to the plate v, as in
the previous arrangement, by screwing its screw c into a nut adjustable in a slot
in a filling piece between the double plate v. The construction of this plate and
arrangement of the set square and fixing screws thereon will be readily under-
stood on reference to the enlarged plan Fig. 5 and the sections Figs. 6 and 7, taken
respectively on lines G G and HH. The bars n may also have extensions n³ fitted
to them by means of metal tongues thereon sliding into the grooves 7, or a metal
plate fixed on the extension bar may overlap the bar n, and be secured thereto by
a setting screw.
It will be understood that the several parts of the above described instruments
may be made of any suitable material such as metal, wood, ebonite, ivory &°, and,
when made of wood they may be faced with metal, as circumstance may require.
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. Constructing the blade of a T square rotatable upon its T head or stock,
which is provided with a circular scale or protractor which in combination with an
index on the blade serves to adjust the blade to any desired angle, the position of
the blade being secured by one or more setting screws, substantially as herein
described with reference to Figs. and 2 of Sheets I, II and III of the Drawings.
2. Constructing the blade of a T square in separate parts secured together by
a metal jointing piece substantially as herein described with reference to Figs. 1,
8, and 9 Sheet I, and Figs. 1, 8, 9, 10 and 11 Sheet II of the drawings.
3. Providing the T head or stock of a T square with an angular metal bar m
Fig. 4 Sheet I for fitting over a plate on the edge of a drawing board clamp so as.
to keep the T head closely in contact, substantially as herein described.
4. Providing the T head of a T square having a removeable blade, with a bar i
Figs. 1, 3, 5, 6 and 7 Sheets I and II pivotted thereto at ¹ and capable of being
made to assume any angle therewith, in which position it is secured by means of
a plate u so as to render the T head applicable either as centrolinead in combi-
nation with the blade a or as an instrument for measuring angles as described with
reference to Fig. 16 Sheet II.
5. Providing the T head of a T square such as is referred to in the preceding
claim with a screw nut n at one or both ends for attachment of the blade a
for the purpose of forming a centrolinead therewith, substantially as herein
described.
6. The use in combination with a T-head such as is referred to in the preceding
claims, of lengthening bars SS for the purpose described with reference to Figs.
7. Constructing set squares of two parts pivotted together at one end and
provided with a quadrant scale or protractor so that while the one part lies against

page_text: the T square the other part can be adjusted to any desired angle relative thereto,
and can be secured in that position by one or more setting screws, substantially as
herein described.
8. The combination of the set square nn Fig. 1 Sheet III with the blade a of
a T square to form a centrolinead, substantially as herein described with reference
to Figs. 3, 5, 6 and 7 Sheet III.
9. The use in combination with the bars n n of the set square, of lengthening
bars n³, for the purposes described with reference to Figs.
10. Combining the slotted parts nn of the set square Fig. 1 Sheet III with
connecting links hh to form a parallel ruler, substantially as described with
reference to Fig. 8 Sheet III.
11. Providing the slots rr of the parts nn of the set square Fig. 1 Sheet III
with points and combining them by means of a screw u fitting into nuts
sliding in the slots thereof, so as to form proportional compasses, substantially as
herein described with reference to Figs. 9 and 10 Sheet III of the drawings.
12. Constructing the clamps of drawing boards with a metal edge S having
a groove in the clamp behind it so that an angular bar N on the T square can
overlap the said edge substantially as herein described with reference to Figs. 1 and 4
Sheets I and II.
Doted thin 20th
1
1000