Improvements in Calculating Machines.
Year: 1891

page_text: Date of Application, 27th Jan., 1891-Accepted, 4th Apr., 1891
COMPLETE SPECIFICATION.
Improvements in Calculating Machines.
[A communication from abroad by HENRY C. HART, of Detroit, Wayne County,
State of Michigan, United States of America, Manufacturer.]
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323, High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion, 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 calculating machines, preferably of the type having
three graduated dials provided with movable pointers, one of which is moved by
a vibrating lever.
The object of the invention is to provide means for varying the stroke of the
vibrating lever in proportion to the desired multiplicand and varying the lengths of
the arms of the lever in proportion to the desired multiplier.
To accomplish this object the invention involves the features, the combination or
arrangement of devices and the principles of operation hereinafter described and
claimed, reference being made to the accompanying drawings, in which :-
Figure 1 is a rear elevation of a calculating machine embodying the invention.
Figure 2 is a similar view showing parts broken away to more clearly exhibit the
operating devices.
Figure 3 is a front elevation of the machine.
Figure 4 is a side elevation of the same.
Figure 5 is a detail sectional view showing the pointer shafts.
In order to enable those skilled in the art to make and use the invention, the
preferred construction will now be described in detail, referring to the drawing
where the letter X indicates a case or fraine having at the front three concentric
dials C, D and E, each graduated to suit the conditions required, and separated by
circular slots or spaces in which move the pointers G and E¹ for the dials D and E.
The main portions of these pointers are arranged in rear of the dials C and D,
and the intermediate dial D is supported by bridge pieces c or otherwise. The
graduations of the dials are intended to represent the three elements of an
operation in multiplication, to wit; the multiplicand, the multiplier and the product,
and it is preferable to place the graduations for the product on the outer dial E,
which is the indicating or registering dial of the machine.
The graduations of the dial C, Figure 3, may represent cents or dollars and the
graduations on the dial D may represent ounces or pounds, in which event the
pointer E of the indicating or registering dial will indicate the price of a certain
number of ounces or pounds at a given price per ounce or pound.
The letter a indicates a rotary shaft having at its inner end a sprocket-wheel A',
and at its outer end portion a pointer F1 and a thumb-wheel A, and on the shaft is
sleeved a hollow shaft H2, carrying at its outer end the pointer G and at its inner
end a pinion H¹. A hollow shaft G³ is sleeved on the shaft H and carries at its
outer end the pointer E' and at its inner end a pinion G³.
A guide rod J is secured on the back of the, case or frame preferably parallel
with the vibrating lever M when the latter is at its highest or initial position and
on the guide rod slides a carriage K, the range of motion of which is limited by a
stop, fixed on the guide rod.
An endless metal belt A² runs over the pulleys I, 11, journaled on shafts in the
frame and said helt engages with the sprocket wheel A'. The
haak of the cosa
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page_text: belt A is connected with the carriage K, whereby the motion of sprocket-whcel A',
in either direction moves the carriage Kalong the guide rod J.
A guide rod L is secured vertically on the back of the frame, passes up between
the guide rod J, and the case or frame, and is encircled at its lower end with a light
coiled spring L³, the object of which is to serve as a counterpoise for a light
rectangular frame L which slides vertically on the said guide rod L. The upper
side of this frame consists of a 'channel bar L which projects at both sides of the
frame L, and is set parallel with the guide-rod J, and in this channel bar rins a
slide block. To prevent the frame L from tilting and binding, and to hold it at
all times in its proper plane, a shaft S, is journaled in said frame L, and carries at
its ends two pinions L, which mesh into racks L', secured to the case or frame X
whereby both sides of the frame L are forced to move equally, no matter at what
point of the channel bar the power is applied.
The vibrating lever M is pivoted at M', Figure 2, to the case or frame of the
machine, and a connecting rod K is movably fastened by keepers K³ to the
carriage K, the lower end of this rod being connected with said lever M by a roller K²
lying in a slot of the lever M. The upper end of the bar K is connected with. the
sliding block located in the channel bar L' and the bar K¹ is shifted along the
channel bar L and lever M. by the movement of the carriage K on the guide rod J.
The distance from the fulcrum M¹ to the roller K², wherever the latter may be in
the slot of the lever, constitutes the short arm of the vibrating lever M. and this
short arm may be varied from nothing to any point included in the distance from
the fulcrum M¹ to the point M³, this point Ms being the end of travel of the rod K
along the lever. The long arm of the lever is that part from the point M' to the
right hand extremity or free end of the lever, Figures 1 and 2, on which free end
is movably mounted the upward extension m of the uppermost one of two cross
heads T which slide on vertical guide rods and are connected by a rack, the
construction being such that the motion of the uppermost cross head T vibrates or
oscillates the lever M, and permits the slight end wise motion required from the facu
that the lever swings in the arc of a circle while the cross-head moves in a
right-line.
A shaft B, journaled in the case or frame is provided with a thumb wheel B'
and two pinions b, b¹, the pinion having the same number of teeth as the
pinion and the pinion being preferably larger than the pinion and meshing
into the rack. The rotation of the shaft B causes the rack to rise or fall and
consequently moves the free end of the lever upward or downward.
A double segment His pivoted to the case or frame, 'one'end meshing into the
pinion and the other end into the pinion H', so that whatever notion is com-
municated through shaft B to the pinion will be exactly transmitted to the
pinion Hand pointer G.
A rack G secured on the side of frame L meshes, into the pinion G₁, so that the
vertical motion of the frame L moves pinion G and the pointer E'. When all
the pointers are at zero the positions of the carriage K, rod K, and frame Lare
as shown in Figure 1, where the fulcrum M' of the lever M is directly opposite the
roller K, at which point the connecting rod K' is connected with the vibrating
lever. The lever M should be however, at the top of its stroke, instead of the
bottom, this position being reversed to uncover the parts lying behind and better
illustrate the invention. In this position, the motion of said lever will not in any
way affect the connecting rod K₁, and therefore the lever M is free to move without
moving the frame L, so that if the shaft B be rotated, the lever M will move and
the pointer G will be rotated, but the remainder of the mechanism and pointers
will stand stationary. But if the shaft be turned through one-half a rotation,
the pointer F is caused to traverse one-half the dial C. This will also rotate the
sprocket wheel A¹ through half a rotation and move the carriage K one-half-its
total travel on guide rod J. The point of connection between the rod, and
lever M will therefore be shifted to a position equal to one half of the total distance
between M', M³, and of course the block e will also move an equal distance on its

page_text: channel bar. If as shown in Figure 3, this causes the pointer F1 to stand at the
figure 25, it puts the mechanism in such position that any motion given to pointer G
will cause pointer E¹ to indicate or register twenty-five times the figure indicated
by pointer G, in this manner. Motion of the shaft B causes the pinion b acting
through the segment H to operate the pinion H¹ and thus move the pointer G,
while the pinion 61 depresses the rack, which, when the pointer G is at zero, is
at its highest point and draws down the free end of the lever M, thus drawing down
the connecting rod K', and with it the frame L. This causes the rack G on the
frame L, to rotate the pinion G and move the pointer E. It is evident that as
pinions and H¹ are equal the pointer G will move through exactly the portion of
a circle through which the shaft B moves. Now, if the mechanism through which
shaft B actuates lever M is connected with said lever at the point M³, which is the
ultimate limit of travel of roller K' on said lever, as shown in Figure 2, but is not
the point on said lever at which said roller is supposed in this description to stand,
such supposed point being half way between M1 and M³, and the pinions and Gi
each having the same number of teeth, on moving the lever M, the roller K² will
travel one half as far as the point M³ travels, and the frame L will be drawn down
one half as far as the point M³ of the lever M moves, thus moving pointer E' one
hálf as far as pointer G moves.
Inasmuch as the number of divisions into which the dial E is graduated is the
multiple of the highest numbers of the dials C and D, the pointer E will indicate
the multiple of the numbers indicated by the pointers F1 and G. And this ratio
and result will continue however the relative lengths of the two arms of lever M
may be varied.
In the construction shown in the drawings, the mechanism by which lever Mis
actuated is as a matter of convenience connected to said lever at the free end of the
lever or at the point n which is at a greater distance from the fulcrum M¹ than is the
point M³. It follows therefore that with this construction the two arms of the lever
cannot be equal and that, to compensate for this, the mechanism that moves the free
end of the lever must be to the mechanism which moves the pointer E' as the
distance Mm is to the distance M-M³, but this is done by making the pinion
proportionally greater in number of teeth than the pinion G', the teeth on both
pinions being of the same size. It is further evident that the relative movement of
the free end of lever M and of the connecting rod K' will vary with the varying
distance of the roller K2 from the fulcrum M of the lever M and that as this
distance is determined by the amount of rotation given to the shaft a, the distance
between the fulcrum Mand the roller K² may be varied to suit any desired figure
indicated on dial C, and that when this distance has been adjusted the same
proportional rate of motion will be imparted through frame L and rack G² to the
pinion G¹ and pointer E' by the same motion which carries the free end of the lever
through the desired portion of its stroke. It follows therefore that the principle of
the machine consists in varying the stroke of a vibrating lever in proportion to the
desired multiplicand and varying the relative lengths of the arms of the lever in
proportion to the desired multiplier. It is also evident that the form and arrange-
ment of the mechanism which varies the relative lengths of the lever which actuates
the lever, and which is actuated by the lever, may be varied widely from that which
has been illustrated without departing from the principle of the invention.
In the preferred form of the invention as exhibited by the drawings, the registering
mechanism comprises the dial E, the pointer E, the rod K', the frame L and its
concomitants, the rack G² and the pinion carrying shaft. G³ so that such registering
mechanism is operated by the vibrating lever. The mechanism for shifting the
point of contact of the registering mechanism with the lever (that is, the contact of
the rod E' with the lever) comprises the thumb wheel A. and the shaft a the sprocket
wheel A', the belt A2 and the carriage K, moving on the guide rod J. Mr. Hart
believes himself to be the first to construct a calculating or multiplying machine
wherein a vibrating lever continually varies the lengths of the two arms and
continually varies its stroke in proportion to the desired multiplier and the desired

page_text: multiplicand and therefore he does not confine himself to the specific registering or
shifting mechanisms described and shown, for they may be modified or varied without
departure from the spirit of the invention.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. In a calculating machine a vibrating lever, mechanism substantially as
described for moving said lever through any desired portion of its stroke,
registering mechanism adapted to be operated by the motion of said lever, and
means substantially as described for shifting the point of contact of said registering
mechanism with said lever, substantially as and for the purposes set forth.
2. In a calculating machine, the combination with a pivoted lever having one arm
connected with actuating mechanism, of an indicator adjustably connected with the
other arm, substantially as and for the purposes set forth.
3. In a calculating machine, the combination of a vibrating lever, mechanism
substantially as described for moving said lever through any desired portion of its
stroke and for indicating said movement, means substantially as described for
varying the relative lengths of the arms of said lever and for indicating said
changes and an indicator adjustably connected with and actuated by said lever,
substantially as and for the purposes set forth.
4. In a calculating machine, the combination of three graduated dials the third
having as many divisions as the product of the highest numbers on the other two
and each dial having a movable pointer, a movable lever adjustably connected with
the pointer of said third dial, mechanism for moving one of said pointers and
proportionally varying the connection between said lever and the pointers of the
third dial, and mechanism for simultaneously moving the remaining pointer and said
lever, substantially as and for the purposes set forth.
5. In a calculating machine the combination of the dials C, D and E, the
pointers F, G and E¹, the lever M adjustably connected with pointer E', the
shaft a, connected with pointer F¹, and with the connection between lever M and
pointer E, and the shaft B connected with lever M and pointer G, substantially as
shown and described.
Dated this 26th day of January 1891.
WM. P. THOMPSON & Co.,
Agents for the Applicant.