IMPROVEMENTS IN MACHINERY FOR CALCULATING PURPOSES
Year: 1878

page_text: LETTERS PATENT to John Purvis Hawtrey, of Aldin House, Slough, in the
County of Buckingham, Schoolmaster, for the Invention of "IMPROVEMENTS IN
MACHINERY FOR CALCULATING PURPOSES."
PROVISIONAL SPECIFICATION left by the said John Purvis Hawtrey at, the
Office of the Commissioners of Patents on the 28th September 1878.
JOHN PURVIS HAWTREY, of Aldin House, Slough, in the County of Buckingham,
Schoolmaster. "IMPROVEMENTS IN MACHINERY FOR CALCULATING PURPOSES."
The improvements consist in constructing machinery in the shape of discs or
circular plates, and in working them concentrically under and in connection with a
fixed plate or dial having upon it a scries of. consecutive numbers adjoining or near
to an opening, said discs bearing on or near their peripheries figures intended to
appear through such opening, each disc to have one or more denominations of
figures. And in constructing machinery of two or more such discs placed concen-
trically, and so that they may be worked independently of or to actuate each other ;
for instance, in a pounds, shillings, and pence machine so that the movement of the
disc appropriated to pence shall at desired intervals control the shillings' disc and
the shillings the pounds' disc; the whole movements being effected by means of a
style placed in slotted recesses situated at or near the moving figures and within
the said openings. Also in the construction of locking or controlling apparatus to
be actuated by the motion of the discs or one of them, and serving to liberate, check,
and control said discs at their proper places when actuated by the said style. The
improvements may be conveniently performed by making the machinery of metal
or other sufficiently hard substances, and the locking apparatus of metal or other
sufficiently hard substances with springs, cams, pawls, and ratchets, or other
equivalent devices.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Purvis Hawtrey in the Great Seal Patent Office on the 28th
March 1879.
JOHN PURVIS HAWTREY, of Aldin House, Slough, in the County of Buckingham,
Schoolmaster. " IMPROVEMENTS IN MACHINERY FOR CALCULATING PURPOSES."
The improvements consist in constructing mechanism in the shape of flanged
discs or rings disposed concentrically within fixed circular guides with recesses at
the requisite relative distances in their flanges under and in connection with one or
more fixed slotted face plates or dials upon which are indicated one or more series
of figures or arithmetical symbols arranged in the form of a curved scale or scales
conveniently arranged in contiguity to the slots in the face or faces, the said discs
or rings having recesses in their flanges, and bearing on their faces other figures or
symbols intended only to appear and be read at or through what I call result
apertures or openings, the said discs or rings being furnished with holes for the
insertion of an actuating style, which holes appear through the face or dial at
intervals corresponding to the scale upon it, the said holes being intended for the
insertion by the person using the machine of a style whereby the disc or ring may
be actuated in a given direction to an extent controlled by the style coming against
or in contact with the ends of the slots, the said discs or rings being arranged to
produce any desired combination or relative degree of action in each other by
means of locking or controlling apparatus brought into action by the use of the
machine and consequent motion of the said discs or rings. The improvements may
be conveniently performed by using a combination or train of toothed wheels
controlled by pawls, springs, detents, ratchets, and stops, or other equivalent
devices made of metal or other hard substances. The accompanying two Sheets of
Drawings are intended to show practical and convenient modes of construction.
Figs. 1 to 12 relate to an 8. d. adding apparatus; Fig. 1 being a plan, Fig. 2, side
elevation; Fig. 3, plan of apparatus with dial plate A removed; Fig. 4, plan of
apparatus with numeral rings B, C, D, and E removed; Fig. 5, cross section of
apparatus; Fig. 6, plan of apparatus with ratchet wheel gear removed; Fig. 7,
underneath views of pawl plates; Fig. 8, side elevation of said plates; Fig. 9,
underneath plan view of numeral ring D; Fig. 10, underneath plan view of ring C;
Fig. 11, side view of ring D; Fig. 12, side view of ring C; the various parts are of
metal or other hard substances, except the frame or casing, which may be of any
suitable material. Figs. 13 to 22 relate to a simple number-adding apparatus ;
Fig. 13 being a plan of same; Fig. 14, side elevation; Fig. 15, plan with dial plate
removed; Fig. 16, plan with numeral rings D, C, removed; Fig. 17, cross section of
same apparatus; Fig. 18, plan of same apparatus with ratchet gear removed;
Fig. 19, underneath plan of ring D; Fig. 20, side view of said ring D; Fig. 21,
underneath view of ring C; and Fig. 22, side view of ring C. In the said Figures
1 to 12, A is the dial plate; B, first or inner pounds dial; C, second pounds dial or
pound units; D, third or shillings' circle; E, fourth or pence circle; e, recess in ring
flange; e, pawl recess; e", cam pawl; b, ratchet wheel to first dial; 6¹, cam stop;
61, cam pawl; 611, ring recesses; c, ratchet wheel; c', holes in ring circle; c¹, stop
cam; c, guide recesses; c¹111, cam pawl; d, ratchet wheel; d', holes in ring circle;
d", cam stop; d, guide recesses; f, ratchet spring; f', ratchet catch; g, ratchet
spring g', ratchet catch; h, spring; h', stop notches; 1, 2, 3, pins or studs. In
Figs. 13 to 22, A is the dial plate; B, wood frame or casing; C, small and inner
ring; D, large ring; e, recess in flange; e¹, pawl recess; e¹¹, cam pawl; c, ratchet
wheel to ring C; f, cam pawl; c', holes for style in rings; g, ratchet spring; g',
ratchet catch; 1, pin; E, ratchet wheel. As regards the 8. d. apparatus, I have
shown 4 series on the pence ring, two on the shillings, and the pounds in four
series of units with 1 to 39 in tens, with recesses and pawls, &c., to correspond, so
that with this machine we can work up to £399-19-11, and I can when desired,
add a fraction of pence ring or rings and increase or diminish the number of rings.
I use this machine by firstly setting all the various and movable numeral discs or

page_text: rings to show zero at the result apertures 0, 0, 0, as shown in Fig. 1. Suppose we
wish to add £7. 18. 11 to £9. 14. 2, I take a style or other conveniently pointed
instrument, place it into the hole in the pence or outer ring at or opposite 11, and
draw this ring round in the direction of the feathered arrow as far as the curved
open slot in the dial plate will allow. I then do the same with the shillings' ring,
fixing the style at 18, and then the same with the pounds at 7; these three move-
ments as indicated by the feathered arrows, causing £7-18-11 to show at the
three result apertures instead of 0, 0, 0, as at present. I then proceed again to the
pence hole at 2, and draw the pence ring in the direction of the arrow as far as the
slot in the dial plate will allow, thereby causing the pence ring to interlock or
engage with the shilling ring by means of its cam-shaped pawl el coming into
contact with one of the fixed stud pins 3, and thereby causing the former to project
and engage with the ratchet wheel d on the shillings' wheel D, and so carry the
shillings wheel forward, one (shilling) in the same direction; as the pence wheel
moves, the cam pawl which was engaged in the ratchet wheel will, by coming into
contact with the fixed circular guide be caused to resume its original place, the
shilling ring being prevented from travelling or moving forward more than one
(shilling) by means of a detent " actuated by the teeth of the shillings' wheel, and
forced back into its normal place between two consecutive teeth of the shillings'
wheel by the wall in a recess e of the pence wheel E, and thus as it were "carrying
forward" one shilling. I then proceed to shillings' hole at 14, and draw the
shillings' ring in the direction of the arrow as far as the slot in the dial plate will
allow, and as the last figure in the series on the shillings' ring passes the appro-
priate recess in the pounds ring, the shilling ring engages the latter by similar
mechanical contrivances or arrangements, and in manner as previously described as
to the pence and shilling rings, thus interlocking with it and so "carrying" one
(pound); and then I proceed to the pounds' hole at g, treating this ring as before,
and by a similar contrivance to that as above described, the outer pounds' ring
causing 1 on the ten (pounds) ring to be carried forward. When these three move-
ments by the style in the direction shown by the dotted arrows produce at the
result apertures £17-13-1, replacing the £7-18-11. I would remark that by
slight and appropriate alterations of the numerals or devices and gear, and acting
upon the same principles, the machine can be adapted to suit any foreign money or
English or foreign weights and measures or other quantities. From what has been
said, the working of the simple numbers-adding machine, as shown in the Drawing,
can be readily understood, and I would merely say that this, as well as the € 8. d.
machine, may be smaller or larger, and with additional circles or rings, and may
have fractions of number rings added or not as desired. The recesses, pawls, and
pins, as also the circular guides and their recesses which serve as the interlocking.
or carrying apparatus being arranged at necessary intervals according to the nature
of the work to be accomplished by the machine, as shown in the £8. d. machine, it
will be seen that they are differently spaced to those shown in the simple adding
machine.
In witness whereof, I, the said John Purvis Hawtrey, have hereunto set my .
igned, sealed, and delivered by
the said John Purvis Hawtrey
in the presence of
R. H. BARRETT,
Sol.,
Slough
JOHN PURVIS HAWTREY. (L.S.)