Improved Means of Combining Harmonic or other Movements in One Plane, and Transmitting and Recording the Resultant Motions.
Year: 1897

page_text: Date of Application, 18th Feb., 1897
Complete Specification Left, 18th Nov., 1897-Accepted, 24th Dec.,
1897
Improved Means of Combining Harmonic or other Movements in One
Plane, and Transmitting and Recording the Resultant Motions.
EDMUND BASIL WEDMORE A.I.E.E. 20 Queen Square Bloomsbury London W.C.
Demonstrator in Physics and Electric Technology. do hereby declare the nature
of this invention to be as follows:-
The invention consists of modifications of a special linkwork and methods of
applying the same.
The special linkwork (See Fig. I) consists of six bars connected together by
joints, and pivots as shown, and so proportioned that the parts A B D C and
GFDE shall be similar figures;-i.e., AB: FG: AC: EG: BD:FD: CD:
ED. If motion is given to any two of the points A, D, and G, the remaining
point gives a resultant motion, varying in its proportions according to the pro-
portions of the linkwork, and varying in direction and amount in direct proportion
to the corresponding variations of each of the two moving points. Again if one
of the points A, D, or G be fixed, then any motion given to either of the other two
will be transmitted to the third altered in proportion according to the
ratio A BDC to GFDE.
The modifications claimed are as follows; -
1st. Bending the links BF and CE at the point D, each through the same
angle (See Fig II), still retaining the similarity of the figures ABDC and
GFDE, so that motions may be combined or transmitted at any convenient angle
other than that proper to each motion.
If, for instance, simple harmonic motion be given to the points A and G (See
Fig II), both motions being in the same direction, then the point 1) will receive
a motion which is the resultant of two harmonic motions similar to those given to
the points A and G but combined at an angle A D M which is the angle through
which the links BDF and CDE have been bent. If again either of the points A, D,
or G be fixed, then any motion given to one of the remaining two will be trans-
mitted to the third altered in proportion and direction according to the proportions
of the linkwork.
2nd. Adding to the linkwork, either in its original or modified form, lengthen-
ing bars AH and GJ (Figs III a & b) at the points A and G, constrained in any
convenient manner to point towards the point D, and with lengths in the pro-
portion of ABDC to GFDE, always retaining the similarity of the two sides of
the linkwork.
In Fig. III a, these bars are shown in the form of tubes sliding on rods K D
and LD. In Fig. III b, the bars are shown produced to pass through bearings
on either side of the point D, the relative distances of the bearings from point D
being in the same proportion as that of the figures A B DC to GFDE to retain
in all cases the similarity of figure.
I propose to use these lengthening bars in cases where it is more convenient or
suitable to have only one link directly attached to A or G.

page_text: point gives a resultant motion, altered in its proportions according to the pro-
portions of the linkwork, and varying in direction and amount in proportion to
the corresponding variations of the two moving points. Again, if one of the
points A, D, or G, be fixed, then any motion given to either of the other two will
be transmitted to the third, altered in proportion according to the ratio A BDC
to G F D E.
The modifications I make are as follows;
-
First Modification.-Bending the links BF and CE, at the point D, each
through the same angle (see Fig II), still retaining the similarity of the
figures A B D C and G F D E, so that motions may be combined, or trans-
mitted, at any convenient angle other than that proper to either or both motions.
For example, if simple harmonic motion be given to the points A and G (Fig. II),
the motions being in parallel directions, then the point will receive a motion
which is the resultant of two harmonic motions similar to those given to the
points A and G but combined at an angle A D M which is the angle through which
the links BD F and CD) E have been bent. If again either one of the points A, D,
or G, be fixed, then any motion given to one of the remaining two points will be
transmitted to the third, altered in proportion and direction according to the pro-
portions of the linkwork.
Second Modification. Adding to the linkwork, either in its original or modified
form, lengthening bars AH and GJ (figs III A & B) at the points A and G,
constrained to point towards the point D, and with lengths in the proportion of
ABDC to GFDE, always retaining the similarity of the two sides of the link-
work. I propose to use these lengthening bars in cases where it is more con-
venient or suitable to have only one link directly attached to A or G. Where the
motions to be transmitted or combined are unidirectional and lie in lines parallel
with the links AH or GJ, then those links may be produced in either direction
any convenient amount independent of the proportions of the rest of the linkwork.
I constrain these bars in either of two ways, as follows;-) I attach bars KD
& LD pivoted at the point D, and cause the lengthening bars to bear on these
bars on at least two points, so that their motion is thereby constrained in the lines
of the bars K D & L D to which they are respectively attached. In Fig III A
this form of constraint is shown, the lengthening bars A H and GJ being in the
form of tubes (which may or may not project over the ends of the bars KD and
LD). b) I produce (Fig III B) the lengthening bars HA and JG till they pass
through bearings on either side of the point D, the relative distances of the
bearings from the point D being such as to retain the similarity of figure.
particular case of this form of constraint would be where the distances of the bear-
ings from the point D were made zero, in which case the bearings would either
have to be situated one above the other on the point D, or they would have to be
concentric.
A
Third Modification. Dividing the original linkwork, Fig I, at the points A or G,
or both A and G, Fig IVA, so that the movements to be given to or received from
the points A or G, or both A and G, may be separated into two components, acting
at any moment along the lines AB, AC, GE, or GF respectively. Four uni
directional motions acting approximately along the lines A B, AC, GE, and GF
may be approximately combined. Provided that the movements given to A 1,
A 2, G1, and G 2 (Figs IV A & B) are small the point D will give a very approxi-
mate resultant of those motions, var ed of course in proportion according to the
When more convenient the
lengths of the parts DB, DC, DE, and DF.
links AB, AC, GE, or GF may be extended in either or both directions (see.
Fig IV B), any convenient amount regardless of the proportions of the rest of the
figure. The accuracy of the resuitant motion however will be greatest when the
diametrically opposite links are of equal length, for it will be seen that
the links AC, CE, and EG, or the links AB, BF and FG, when taken together,
each forms a Watts straight line motion.
I also apply my first two modifications to another form of the original link-

page_text: point being so proportioned as to retain the similarity of figure holding in the
rest of the linkwork.
5th. In the first form of the well known pantagraph linkwork herein before
described, or in modifications of that linkwork claimed in my first claim, to divide
the linkwork at the points A. and G, for the purposes herein before described.
6th. In the application of the linkwork modified in the manner described in my
5th claim, to produce the separated links B A, CA, E G, and F G, any convenient
amount in either direction, for the purposes herein before described.
7th. In attaching a recording instrument to any point in any form of the link-
works herein described, or in any other linkwork used for a similar purpose, for
the purpose of recording the motion of that point, a method of attachment which
consists in forming a tube about the point and passing the recording instrument
through that tube, so that the pressure of the recording instrument, on the surface
en which the record is to be made, shall be independent of the linkwork and depend
only on pressure applied directly or indirectly through the instrument itself,
either by virtue of its natural weight or by any other known means.
Dated this 18th day of November. 1897.