improvements in Apparatus for forspective Drawing
Year: 1886

page_text: improvements in Apparatus for forspective Drawing
I, ROBERT EDMUND CREASEY, of 11 Cambridge Avenue, Jersey City in the
State of New Jersey, United States of America, Gentleman, do hereby declare the
nature of my invention for "IMPROVEMENTS IN APPARATUS FOR PERSPECTIVE
DRAWING," 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 an apparatus by means of which different parts of an
object to be drawn in perspective may be reduced to the same scale, the apparatus
being so constructed that the scale may be readily altered.
This invention consists in the various features of improvement hereinafter more
fully pointed out.
In the accompanying drawings, Figure 1 is a side view of my improved
apparatus. Figure 2 is a vertical central section, partly in side view, of the same
with the rod removed. Figure 3 is a horizontal section on line x, x, Figure 2; and
Figure 4 is a diagram showing how the apparatus is used.
The letter a represents a drum, made of sheet metal or other material, and
preferably open at its lower end while closed at its upper end by a centrally
perforated head b.
A spindle c extends centrally through drum a, and passes with one end through
head b. Upon the spindle c there is mounted a ratchet wheel, d, and a band
wheel, e, which is located outside of the drum, so as to be readily accessible. The
ratchet wheel d is engaged by a pawl or click, f, attached to the inner periphery
of drum a. The upper end of spindle c, that extends above head b, is perforated
for the reception of a pin that prevents the spindle from dropping out of the drum
though permitting its free rotation. A pair of elastic concave disks, n, n', of which
the disk n is rigidly attached to the spindle while the disk n' loosely surrounds it,
may be arranged at opposite sides of head b to establish a yielding connection
between spindle and drum. To the spindle there is attached one end of a string, 9,
that is partially wound around spindle, c, and passes out of a perforation, h, of
drum a. The outer or free end of spring g is provided with a button, i.
The upper end of drum a is covered by a cap, j, having a socket, k, for the
reception of one end of an upwardly extending graduated rod, l. Upon this rod
there works a slide, m.
The apparatus is used as follows:
The string g is unwound by hand wheel e until the length of the string
unwound is in the same proportion to the distance of the operator from the
hiant

page_text: The pawl f, engaging ratchet wheel d, will prevent further automatic unwinding
of the string, so that the same proportion is maintained during the sketching of
the same object. The button is taken into the mouth and the string is held
somewhat below but in line between the operator and the object A. Next the
slide m is moved up or down until the upper part of the rod above the slide
apparently covers the object.
This part of the rod will be the scale desired, and may be laid off upon the
paper.
Thus one part of the object after the other is taken and is reduced. If the
scale is to be altered, the length of the free portion of the string is increased or
diminished.
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 of drum a and spindle c, with the string g, rod l, and slide m,
substantially as specified.
2. The combination of drum a, with spindle c, ratchet wheel d, pawl f, hand-
wheel 8, and string g, and with the rod l, and slide m, substantially as specified.
3. The combination of drum a, with spindle c, ratchet wheel d, pawl f, hand
wheel e, string g, button i, cap i having socket k, and with the rod land slide m,
substantially as specified.