Improved Method of Marking Out the String Boards of Staircases, and Implement for Use in connection therewith.
Year: 1899

page_text: Date of Application, 1st Feb., 1899-Accepted, 8th Apr., 1899
Improved Method of Marking Out the String Boards of Staircases,
and Implement for Use in connection therewith.
I, JOHANNES ZELTNER-DIETZ, of Nuremberg, in the Empire of Germany, Royal
Counsellor of Commerce, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
The marking out of staircase string boards has hitherto always required a great
consumption of time because it was not founded on any systematic basis, as
treads and risers were tentatively projected or sketched by striking angles until
a suitable position of the same on the plank to be dealt with was found. Such
work required clever and skilled workmen who however required a long time to
do it in, so that this work was time consuming and costly.
By the method which forms the object of this invention the marking out of
stair case string boards can be easily and rapidly effected without special experience
and skill and especially with absolute security by means of an implement specially
suitable for carrying out the aforesaid method.
In the accompanying drawings,
Figure 1 is a plan view of a turned staircase, 18 risers being assumed for the
height of the steps, that is to say 17 steps are necessary for this staircase. (The
last riser forms the landing). The division of the stair steps is usually made in
such a way that the risers are all of equal height and the average widths of the
steps or treads are assumed to be similar. The tread surface at the top and bottom
of the staircase are usually of equal width on both cheeks or stringboards whilst
the intermediate treads gradually alter on both string boards.
In the present instance it is for instance assumed that the treads 1, 2. 3 and 15,
16 and 17 are of equal width at both string boards, whilst the intermediate treads
from 4 to 9 become gradually wider at the outside and narrower at the inside and
from 10 to 14 gradually again narrower at the outside and wider at the inside.
It is evident from the plan of a staircase shown here as an example that in the
left hand string I-62/3 steps are contained, in string hoard II there are 3 and %
steps and in string board III again 6 and 2/3 steps. In the present instance of
a curved or turned staircase, as the width of the treads alters in the separate
string boards or cheeks, the average width of the treads in the string boards I,
II and III is first ascertained (the average width equals the length of the string
boards in plan divided by the number of treads lying therein). The scale for the
pitch or rise is obtained from the height of the floor or story and the number of
risers. As soon as these two measures are ascertained, the marking out of the
staircase by means of the special implement which will now be described is
uncommonly simple.
This takes place by means of the angle gauge shown in Figures 4, 5 and 6.
the longer arms A and C of which are pivotally connected with one another and
may be adjusted in position to one another by means of a third but vertical arm B
adjustable on both arms A and C and at any time vertically adjustable thereon
D

page_text: '
"
A
(according as right or left string boards are to be marked out) and which may be
fixed together by means of a screw 6¹. For this object all three arms A, B and C
have slots a b and c through two of which the set screw b¹ projects and in the slot c
of which the arm B is adjustable. All three arms are provided with scale mark-
ings and two projections or contacts d and f are arranged at the point of rotation
of the two arms A and C vertically to these latter in such a way that the inner
contact edges pass through the centre of the hinge (point of rotation). A further
contact or stop d', capable of being adjusted in the slot a and fixed therein, serves
for enabling a given measure (rise) to be marked by its corner or angle on the
arm B. By means of this angle on the stop the position of the hypothenuse
of the right-angled triangle (in the arm A) may be ascertained, the said projec-
tion being arranged exactly in the centre line of the slot a which line passes
through the centre of the hinge, and the inner edge of the arm B passing through
the angle, which hypothenuse forming the centre of the slot a passes through the
point of rotation (centre of the hinge) and through the, above angle of the stop d¹
and the exact length of which is given by the distance apart of the two stops d
and . If a planed lath W be nailed on the side of the string board I and the
instrument be adjusted with its two arms B and C to the angle of rise (average
width of tread and height of rise) and laid with its hypothenuse arm A on this
lath W, the horizontal lines for the steps 1, 2, 3, 4, etcetera, may be easily marked
out, as they have an equal vertical distance apart, by means of the divisions
(scale) on the arm B (heights of rise). For laying out or marking the verticals
of the steps (risers) lving at varying distances apart two contacts or stops a and h
arranged on the arm C are employed which are adjusted each time to these different
treads or widths of step on the string board I in such a way that g rests on the
front vertical, and by means of the stop h. the vertical for the next step is proiected.
In this manner there is first obtained the design of steps shown on the left of
Figure 2. If in the same the actual thicknesses of the wood of the risers and
treads and also the profile of the tread nosing (see Figure 2 to the right) be taken
and then the distance from the front nosing and from the rear end of the treads
to which the string board is to project above and below the steps be added (so
that the whole width of the string board is obtained) the points for the upper and
under border lines of the stringboard is obtained. (In the present case these are
regular curves).
In a similar manner for the other string boards II and III and also the right
hand (inner) string boards IV and V, the division of the steps (form and position)
are obtained in a very short time. whilst as before the horizontal distances are
always ascertained corresponding to the distances to be deducted from plan I
by means of the stops G and H.
The marking out may be carried out by the method herein before described with
the use of the implement described in so simple a manner that even the most
unskilled workman learns the same in a very short time. The advantage consists
also not only in the short time required for marking out and the use of unskilled
workmen but also particularly in the security and accuracy of the work afforded
by the mechanical execution.
The method when laying out straight stair cases is of course simpler because
here the widths of the treads remain equal. With an exact handling of the
implement an absolute security is afforded in the carrying out of the separate
parts and errors are excluded.
This method may also be employed for stone staircases of all kinds by using
this implement.
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. A method of marking out stair case string boards of wood or stone, character-
ised by the angle of inclination of the stringboard being determined for

page_text: section from the number of steps pertaining to it and from the total height of
said steps and total width of same, which last may be gathered from the con-
struction plan, and by the steps being marked out on the stringboard at said
angle at equal vertical distances apart, whilst the varying horizontal distances
apart (tread) of the steps can be measured off from the construction plan and
marked and then the thicknesses of the planks for treads and rises as well as the
tread nosing and distance of the upper and under border line of the string board
from the nosings and rear ends of the treads may be ascertained and therefrom the
form of the string board marked out, substantially as herein before set forth.
2. For carrying out the hereinbefore described method of marking out stair
case string boards of wood or stone, an implement consisting of an angle piece the
longer arms (A and C) of which are hinged or pivotally connected at one end one
to the other and which may be adjusted and fixed in their inclination relative to
one another by means of a third arm (B) which is always vertically upright and
adjustable in slots in the aforesaid arms (A and C) namely in the arm (C) for
marking out the left string board and in the arm (A) for marking out the right
set screw (6) which passes through
string board and is adapted by means of
slots (a and b) in the arms (A and B) so that by means of scale markings or
divisions on the three arms (A B C) and contacts or stops (d f g and h) the
marking out of the string boards may be rapidly and simply carried out by means
of this implement or instrument with the help of laths (W) temporarily affixed
to the string boards substantially as hereinbefore described.
1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.