An Improved Mechanical or Artificial Arm.
Year: 1892

page_text: Date of Application, 12th Apr., 1892
Complete Specification Left, 16th Dec., 1892-Accepted, 28th Jan., 1893
PROVISIONAL SPECIFICATION.
An Improved Mechanical or Artificial Arm.
I, JULES FRANÇOIS GEORGES HARAN of 12 Rue Lacépède, Paris, France,
Surgical Bandage Maker, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an improved system of artificial arm so constructed as
to be capable of simultaneous or independent movements at the elbow, wrist, and
finger joints, that is to say the mechanism is so arranged and combined that all the
members of the artificial arm and hand are capable of being worked under con-
ditions identical with, and in a manner similar, as regards precision and natural
appearance, to, those governing, and appertaining to, the natural human arm.
In this improved system of artificial arm, initial point of departure for these various
movements is taken at the stump, if there be one available, otherwise from the
shoulder, or even from the other arm, should the stump not only be absent but the
shoulder be disarticulated. The mechanism is therefore not dependent on the
presence of a stump for its operation and it is so constructed that a very slight
effort is sufficient to produce all the movements that may be required, without
giving rise to any apparent contorsion of the body, these movements being always
under the control of the person wearing the arm. This improved arm is preferably
made of aluminium, for the sake of extreme lightness combined with strength, but
it may be made of other suitable metal or material possessing similar qualities.
Although I do not limit myself in respect of the details of mechanism described,
I have illustrated in the accompanying drawings an example of my improved
artificial arm together with the means of operating the same.
Figure 1 represents (in two views to be considered as one) the entire mechanism
of the artificial arm, each of its parts, i.e. the elbow, forearm, wrist, and hand
being considered as independent of the rest.
Figure 2 is an underside view of one of the fingers, and
Figure 3 a longitudinal section of same on line 1-2 Figure 2.
Figure 4 shews the back of the vest to be applied to the bust and upon which is
mounted the elbow lever whereby motion is imparted to some of the parts as
hereafter described.
Figure 5 shews the mechanism mounted on a vest similar to that represented in
the preceding figure and serving to operate the artificial arm when the shoulder
itself is disarticulated.
Figure 6 shews, in vertical longitudinal and cross-section, the rotary motion of the
wrist-joint.
Figure 7 is a cross-section of the elbow-joint, on line 7-8 Figure 1.
I will first describe the mechanism of the arm generally, with reference to
Figure 1 and upon the assumption that a stump is available upon which the upper
part of the artificial arm will fit tightly, so as to partake of all its movements.
The motions of the five fingers are each controlled by a set of cords a united at b
to a cord c so as to be thereby all operated together. This cord is suitably guided
and passes over a pulley d mounted nearly at the point of articulation of the elbow
joint; its other extremity is attached to a sliding rack e whose other end is attached
to a cord which passes across the back of the wearer, as shewn in Figure 4, and
is connected to the opposite shoulder whereby the movements of the fingers are
imparted. The sliding rack e is engaged and retained by a spring paul h which is
disengaged by the action of a cord i connected to a fixed point of the vest and
operating as hereafter described. The cords a are respectively attached at a to
the underside of the first phalange of the finger to which they correspond and this

page_text: '
phalange is jointed to the next by a spring joint k, these several knuckle joints
tending to keep the fingers straight, whereas the cords a are so led or arranged that
tension upon them causes flexure of the said joints and closure of the hand, this
tension of cords e¹, c, a, and rack being produced by the opposite shoulder as
above stated. The rack being retained by the pawl h, the hand is thereby kept
closed notwithstanding the constant tendency of the spring joints to open them.
The pawl being connected by a cord i to a fixed point at the front of the bust,
the backward motion of the artificial arm causes tension of this cord, disengages
the pawl, and, by liberating cord c, allows the fingers to resume their normally
open position. The thumb and forefinger may be operated independently of the
other fingers, in a similar way, by means of a second rack sliding in the guide and
connectel to, and operating, these two members by cords similar to those above
described as operating the others fingers.
The flexure of the wrist-joint is produced by means of two cords m m' attached
the one to point n upon the hand and the other to point n' at the underside of the
hand. The cords m and m' are respectively attached to fixed points o o' apper-
taining to the upper part of the arm and situated at about the height, and at
diametrically opposite sides, of the elbow joint, the point o being on the upper end
and the point o' ou the underside of the arm. The rotation of the wrist-joint is
effected by the flexure of the elbow-joint through the medium of a lever p pivoted
at p¹ and mounted within the artificial arm. This lever actuates by its forward
end a sleeve 9 turning freely or in roller bearings y, as shewn in Figure 6, within
a guide cylinder fixed to the metal casing of the arm. The cylinder has two
diametrically opposite circumferential slots in which are guided studs = mounted
on the sleeve q.
In order that this rotary motion shall take place only when the arm is extended
the other end of lever has a curved slot in which plays a stud s mounted on
the stationary part s¹ of the elbow-cap so that the studs shall only act on the
lever p on reaching the end of the slot when the arm is extended to a certain
extent. The pivot of the elbow-joint is at t. Assuming the arm to be fixed to
a stump, the various motions above described are produced by the motion of
the stump through the medium of a cord u¹ connected to a fixed point u on the
casing of the upper part of the arm which fits on the stump and to the lower
end of the elbow lever f, Figure 4, so that a slight motion of the stump is trans-
mitted to leverf multiplied by the difference of length of the two arins of said
lever and transmitted by a cord connecting the longer arm of said lever to a
stud fixed to the rotary sleeve of the wrist.
It will be understood that the various cords above referred to are guided by
suitable pulleys and guide eyes.
When the artificial arm is to be applied to a person not only possessing no stump
but having the shoulder disarticulated, the artificial arm above described is combined
with the mechanism hereafter described with reference to Figure 5. The artificial
arm is mounted on bust by means of a joint 1 composed of an inner and outer shell
of which the inner convex one is fixed in the place of the shoulder whilst the
outer concave one turns freely on the first, about a pivot 2. To raise the artificial
arm a cord 3 is fixed to the opposite shoulder, or on the front of the chest, and
attached to the longer arm of lever 4 pivoted at 5 and connected by its short arm to a
vertical sliding rod a drawn upwards by a spring 6 and carrying a spring pawl 7
which engages in the teeth of a rack 8 parallel to the rod x. The upper end of the
rack rod is jointed to a suitable point of the periphery of the outer or movable
part of the shoulder-joint 1 and the downward movement of the rod and of the
rack with which it engages by pawl 7 produces the rotation to the desired extent
of the movable member of the shoulder joint and consequently of the artificial arm
connected thereto; this movable member acting in the same manner as the stump
before referred to in operating the mechanism of the artificial arm before described.
The arm having been raised, it is only necessary that the effort applied by the
other shoulder should cease, in order that the arm may fall by its own weight.

page_text: In order to avoid too sudden a fall, and also to arrest the arm at any desired
point, a stationary pawl 9 is mounted to engage the rack 8 and is combined with a
brake roller 10 acting on the back of the rack rod, the pawl and roller being put,
the one out of and the other into, action by the pull of a cord 10' attached to the
natural arm and operated thereby.
The cord e serves for closing the fingers and the cord for disengaging them and
permitting them to open under the conditions and in the manner described with
reference to Figure 1, the movements of the elbow and other joints being produced
in the manner before described.
It will be understood that as much of the system of artificial arm may be applied,
apart from the remainder, as may be necessary to compensate for an amputation at
the wrist or forearm.
J. F. G. HARAN,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
An Improved Mechanical or Artificial Arm.
I, JULES FRANÇOIS GEORGES HARAN of 12, Rue Lacépède, Paris, France,
Surgical Bandage Maker, 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 :-
This invention relates to an improved system of artificial arm so constructed
as to be capable of simultaneous or independent movements at the elbow, wrist,
and finger joints, that is to say the mechanism is so arranged and combined that
all the members of the artificial arm and hand are capable of being worked
under conditions identical with, and in a manner similar, as regards precision
and natural appearance, to, those governing, and appertaining to, the natural human
arm. In this improved system of artificial arm the initial point of departure
for these various movements is taken at the stump, if there be one available,
otherwise from the shoulder, or even from the other arm, should the stump not
only be absent but the shoulder be disarticulated. The mechanism is therefore
not dependent on the presence of a stump for its operation and it is so con-
structed that a very slight effort is sufficient to produce all the movements that
may be required, without giving rise to any apparent contorsion of the body,
these movements being always under the control of the person wearing the arm.
This improved arm is preferably made of aluminium, for the sake of extreme
lightness combined with strength, but it may be made of other suitable metal
or material possessing similar qualities.
Although I do not limit myself in respect of the details of mechanism described,
I bave illustrated in the drawings accompanying my Provisional Specification an
example of my improved artificial arm together with the means of operating the
same.
Figure 1 represents (in two views to be considered as one) the entire mechanism
of the artificial arm, each of its parts, i.e. the elbow, forearm, wrist and hand being
considered as independent of the rest.
Figure 2 is an underside view of one of the fingers, and Figure 3 a longitudinal
section of same on line 1-2 Figure 2.
Figure shews the back of the vest to be applied to the bust and upon which is
mounted the elbow lever whereby motion is imparted to some of the parts as here-
after described.
Figure 5 shews the mechanism mounted on a vest similar to that represented in the
preceding figure and serving to operate the artificial arm when the shoulder itself
is disarticulated.

page_text: Figure 6 shews, in vertical longitudinal and cross-section, the rotary motion of the
wrist-joint.
Figure 7 is a cross-section of the elbow-joint, on line 7-8 Figure 1.
I will first describe the mechanism of the arm generally, with reference to
Figure and upon the assumption that a stump is available upon which the
upper part of the artificial arm will fit tightly, so as to partake of all its move-
ments. The motions of the five fingers are each controlled by a set of cords a
united at to a cord c so as to be thereby all operated together. This cord is
suitably guided and passes over a pulley d mounted nearly at the point of
articulation of the elbow joint; its other extremity is attached to a sliding rack e
whose other end is attached to a cord e¹ which passes across the back of the
wearer, as shewn in Figure 4, and is connected to the opposite shoulder whereby
the movements of the fingers are imparted. The sliding rack e is engaged and
retained by a spring pawl which is disengaged by the action of a cord i con-
nected to a fixed point of the vest and operating as hereafter described. The
cords a are respectively attached at a to the underside of the first phalange of
the finger to which they correspond and this phalange is jointed to the next by
a spring joint k, these several knuckle joints tending to keep the fingers straight,
whereas the cords a are so led or arranged that tension upon them causes
flexure of the said joints and closure of the hand, this tension of cords e¹, c, a,
and rack e, being produced by the opposite shoulder as above stated. The rack
being retained by the pawl h, the hand is thereby kept closed notwithstanding
the constant tendency of the spring joints k to open them. The pawl / being
connected by a cord to a fixed point at the front of the bust, the backward
motion of the artificial arm causes tension of this cord, disengages the pawl,
and, by liberating cord c, allows the fingers to resume their normally open
position. The thumb and forefinger may be operated independently of the other
fingers, in a similar way, by means of a second rack sliding in the guide and
connected to, and operating, these two members by cords similar to those above
described as operating the other fingers.
The flexure of the wrist-joint is produced by means of two cords m m² attached
the one to point n upon the hand and the other to point n¹ at the underside of
the hand. The cords m and m¹ are respectively attached to fixed points
01
appertaining to the upper part of the arm and situated at about the height, and
at diametrically opposite sides, of the elbow joint, the point o being on the
upper and the point o' on the underside of the arm.
The rotation of the wrist-joint is effected by the flexure of the elbow-joint
through the medium of a lever p pivoted at p¹ and mounted within the artificial
arm. This lever actuates by its forward end a sleeve turning freely or in
roller bearings y, as shewn in Figure 6, within a guide cylinder fixed to the
metal casing of the arm. The cylinder has two diametrically opposite_circum-
ferential slots z in which are guided studs mounted on the sleeve q. In order
that this rotary motion shall take place only when the arm is extended the
other end of lever p has a curved slot in which plays a studs mounted on the
stationary parts of the elbow-cap so that the studs shall only act on the lever p
on reaching the end of the slot when the arm is extended to a certain extent.
The pivot of the elbow-joint is at t.
Assuming the arm to be fixed to a stump, the various motions above described
are produced by the motion of the stump through the medium of a cord u¹
connected to a fixed point u on the casing of the upper part of the arm which
fits on the stump and to the lower end of the elbow lever f, Figure 4, so that
a slight motion of the stump is transmitted to lever f multiplied by the difference
of length of the two arms of said lever and transmitted by a cord v connecting
the longer arm of said lever to a stud v fixed to the rotary sleeve q of the
wrist.
It will be understood that the various cords above referred to are guided by
suitable pulleys and guide eyes.

page_text: When the artificial arm is to be applied to a person not only possessing no
stump but having the shoulder disarticulated, the artificial arm above described
is combined with the mechanism hereafter described with reference to Figure 5.
The artificial arm is mounted on bust by means of a joint 1 composed of an
inner and outer shell of which the inner convex one is fixed in the place of the
shoulder whilst the outer concave one turns freely on the first, about a pivot 2.
To raise the artificial arm a cord 3 is fixed to the opposite shoulder, or on the
front of the chest, and attached to the longer arm of lever 4 pivoted at 5 and
connected by its short arm to a vertical sliding rod a drawn upwards by a
spring 6 and carrying a spring pawl 7 which engages in the teeth of a rack 8
parallel to the rod .. The upper end of the rack rod is jointed to a suitable
point of the periphery of the outer or movable part of the shoulder-joint 1 and
the downward movement of the rod and of the rack with which it engages by
pawl 7 produces the rotation to the desired extent of the movable member of
the shoulder joint and consequently of the artificial arm connected thereto; this
movable member acting in the same manner as the stump before referred to in
operating the mechanism of the artificial arm before described. The arm having
been raised, it is only necessary that the effort applied by the other shoulder
should cease, in order that the arm may fall by its own weight. In order to
avoid too sudden a fall, and also to arrest the arm at any desired point, a
stationary pawl 9 is mounted to engage the rack 8 and is combined with a brake
roller 10 acting on the back of the rack rod, the pawl and roller being put, the
one out of and the other into, action by the pull of a cord 10' attached to the
natural arm and operated thereby.
The cord e serves for closing the fingers and the cord i for disengaging them and
permitting them to open under the conditions and in the manner described with
reference to Figure 1, the movements of the elbow and other joints being produced
in the manner before described.
It will be understood that as much of the system of artificial arm may be applied,
apart from the remainder, as may be necessary to compensate for an amputation at
the wrist or forearm.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
The herein described mechanical arm adapted to reproduce the motions and fulfil
the functions of the natural organs and elbow, wrist and finger joints at will and
without apparent effort, the said system of arm consisting essentially in the com-
bination of the parts of the arm and in the mode of transmitting motion thereto,
substantially as herein specified.
Dated this 10
3000
J. F. G. HARAN,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.