IMPROVEMENTS IN SEWING MACHINES
Year: 1883

page_text: LETTERS PATENT to Auguste Jacques Hurtu of Paris in the Republic of
France, Mechanician, for an Invention of "IMPROVEMENTS IN SEWING
MACHINES"
PROVISIONAL SPECIFICATION left by the said Auguste Jacques Hurtu
at the Office of the Commissioners of Patents on the 25th August 1883.
AUGUSTE JACQUES HURTU of Paris in the. Republic of France Mechanician
"IMPROVEMENTS IN SEWING MACHINES"
This invention relates to that class of sewing machines in which a rotating hook
is used for drawing the loop of the needle thread over a fixed bobbin shuttle or
spool, and the invention consists in certain arrangements of parts which will
permit of the machine being worked with ordinary thread at considerably greater
speed than heretofore without fear of breaking the thread, and without jarring
and shocks which cause noise and loss of force, and also without appreciable wear
of the parts.
In machines of this class it has been found necessary to accelerate the speed at
which the hook travels during one part of its rotation and diminish the speed at
another, and many attempts have been made to do this while increasing generally
the speed of working of the machine but hitherto without satisfactory results.
In carrying out this object the driving shaft is divided in two parts one of
which will retain the name of the driving shaft, and carries the fly wheel and
cams and the other which carries the hook will be termed the hook shaft.
These two shafts are preferably arranged in line one with the other but at a
short distance apart and each carries at its inner end a crank. Each of these
cranks is connected by a connecting rod or link to a crank arranged at opposite
ends of a third or intermediate shaft placed parallel to the divided shaft and
suitably mounted in a pendent bracket secured to the underside of the table or
plate or in any other convenient manner.
The linked cranks are keyed on the shafts at certain relative angles and
connected together in pairs.-By this means a variable motion is transmitted to
the hook, accelerating and diminishing its speed to suit the other movements of
Price G21

page_text: the machine, while maintaining great smoothness of movement in the working
parts and allowing of the machine being driven at a very high speed.
If the cranks of the intermediate shaft are placed at an angle of 153° or
thereabouts to each other the maximum of diminution and acceleration of speed of
the hook with regard to the uniform movement of the driving shaft will be
obtained but if the angle of these two cranks be varied the increasing or decreasing
speed of the hook may be diminished according to requirements.
Let it be supposed that the two cranks of the intermediate shaft are set at the
angle mentioned, the one to the other; and that the needle is at the bottom of its
course to form the loop and that the point of the hook is ready to take this loop;
if a quarter of a turn be given to the driving shaft the hook will make in the
Fame time a half turn during which it will enter the loop and draw it down while
the needle rises.
During the second quarter of rotation of the driving shaft the hook will also
make a quarter turn and will release the loop of thread which is drawn up by the
take up.
At the third quarter of rotation of the driving shaft the hook will make
only one-eighth of a rotation and the stitch will be tightened up. Then during the
4 and last quarter of rotation of the driving shaft the book will make its list
one eighth turn which completes a rotation, the needle redescends to form a new
loop and the point of the hook is returned to its first position.
The same result may also be obtained by employing in combination with the
three shafts above mentioned, a series of plites certain of which are slotted, the
remainder being provided with pins which work therein, or an-intermediate-shaft
with elliptical gearing may be use 1.
t.
Although only two sets of cranks are above mentioned a greater number may
be used the result being greater smoothness of movement practically obviating all
undue wear of the parts.
Besides the above advantages and as an immediate consequence it may be
remarked Hint, with the system of cranks and connecting rods less inclination need
be given to the cam groove which actuates through the usual rocking lever the
needle carrier thus avoiding all shocks and permitting if necessary of further
increase in the speed of the machine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Auguste Jacques Hurtu in the Patent Office on the 23rd February
1884.
AUGUSTE JACQUES HURTU of Paris in the Republic of France Mechanician
"IMPROVEMENTS IN SEWING MACHINES
"
7
This Invention relates to that class of sewing machines in which a rotating hook
is used for drawing the loop of the needle thread over a stationary bobbin shuttle
or spool and the invention consists in certain arrangements of parts which will
permit of the machine being worked with ordinary thread at considerably greater
speed than heretofore without fear of breaking the thread and without jarring
and shocks which cause noise and loss of force and also without appreciable wear
of the parts.
In order to obtain great speed of working in machines of this class it is necessary
to accelerate the speed at which the hook travels during one part of its rotation
and diminish the speed at another and although many attempts have been made to
effect this object a speed of only from One thousand to One thousand two hundred
turns per minute has been obtained with any thing like satisfactory results.
In the Specification of a Patent granted to Alexander Melville Clark on my
behalf for Improvements in sewing machines and dated the second February One
thousand eight hundred and eighty one N° 450 an arrangement of mechanism is
described whereby as many as Two thousand turns per minute have been obtained
in a very satisfactory manner but the apparatus is of such a complicated and
delicate nature that the cost of production precludes its general use:
•
My object in the present Invention is to obtain a yet greater speed say of Two
thousand five hundred turns per minute by the employment of very simple means.
These means consist essentially in the employment of a special arrangement of
coupling in connection with the driving shaft. This driving shaft is divided in two
parts one of which will retain the name of driving shaft and carries the fly wheel
and driving cam the other which carries the hook will be termed the book shaft.
These two shafts are preferably arranged in the same line and at a short distance
from one another and each carries at its inner end a crank. Each of these cranks
is connected by a link or other convenient coupling to a crank placed at opposite
ends of a third or intermediate shaft placed between the other two but on a line
parallel therewith and suitably mounted on a pendent bracket secured to the
underside of the table or plate of the machine or in any other convenient manner.
The cranks are keyed on the shafts at certain relative angles and connected
together in pairs by links-By this means a variable motion is transmitted to the
book accelerating or diminishing its speed to suit the other movements of the
machine at the same time great smoothness of movement in the working parts of
the machine is attained which permits of the machine being driven at very high*
speed.
•
If the cranks on the intermediate shaft are placed at an angle of one hundred
and fifty three degrees or thereabouts to each other the maximum of diminution*
and acceleration of speed of the hook with regard to the uniform movement of the
driving shaft will be obtained but if the angle at which these two cranks are set
be varied the increasing or decreasing speed of the hook may be diminished
according to requirements.
Let it be supposed that the two cranks of the intermediate shaft are set at the'
angle above mentioned the one to the other and that the needle is at the bottom of
its course to form the loop and the point of the hook ready to take this loop if a
j

page_text: quarter of a rotation be given to the driving shaft the hook will make in the same
time half a rotation during which time it will enter the loop and draw it down the
needle at the same time rising.
During the second quarter of rotation of the shaft the hook also will make, a
quarter rotation and will release the thread which is drawn up by the take up.
At the third quarter of rotation of the shaft the hook will make only one eighth
of a rotation and the stitch will be tightened up. Then during the fourth and last
-quarter of rotation of the driving shaft the book will make its last one eighth
rotation which makes up a complete rotation, the needle redescends to form a new
loop and the point of the hook is returned to its first position.
The coupling arrangement above described. will give such smoothness to the
working of the mechanism that notwithstanding the speed of the hook round the
spool carrier the machine may be worked at a speed of Two thousand five hundred
rotations per minute without any fracture of the thread and without producing
any shocks vibration or trepidation a result which has never heretofore been
obtained.
A similar result may also be obtained by employing in combination with the
threo shafts above mentioned plates or discs certain of which are slotted the
remainder being provided with pins which work in the slots or an intermediato
shaft with elliptical or other gearing may be used.
Although only two sets of cranks are mentioned above a greater number may be
used the result being greater smoothness of movement practically obviating all
undue wear of the parts.
Besides the above advantages and as an immediante consequence, it may be
remarked that with the arrangement of cranks and connecting links or their
equivalent less inclination need be given to the cam groove which actuates through
the usual rocking lever the needle carrier or bar thus avoiding all shocks and
permitting if necessary of further increasing the speed of the machine.
In the accompanying drawings I have represented one mode of carrying out my
Invention Fig 1 being a side elevation parily in section of a sewing machine with
the arrangement of double cranks and coupling arrangement adapted thereto and
Fig: 2 a sectional plan view.
Figures 3 3-4 4-5 5-6. 01. are diagrams shewing the relative positions of
the hook and needle carrier and the corresponding positions of the coupling
arrangement at each quarter rotation of the driving shaft.
In the different figures the same letters refer to similar parts.
K is the driving shaft which carries the fly wheel L the driving cam K³ the
stitch regulating cam D and the crank A'. The book shaft K' carries the hook E
and the crank A
Between these two shifts is placed the intermediate shaft H which is freo
to turn in the support or bearing M and carries at its opposite ends the cranks
C. C₁, which are preferably fixed thereto in line one with the other (fig: 1)
The cranks A A' are fixed on their respective shafts so that when the needlo
carrier or bar is at the lowest point of its stroke to form the loop which will be
taken by the point of the hook (fig: 3) they shall be in a horizontal position to
the right. It is at this moment that the slow speed is finished and the acceleration
commences.
Bis the link which connects the cranks A and C together the link B' serving
the same office for the crauks A¹ and C.-N is the stationary bobbin shuttle or
spool placed in the adjustable bobbin carrier O.
The hook E is formed of a hook proper of very hard metal fixed by a screw or
otherwise, so that it may be easily removed when required, to a piece, which I
term the book carrier. The hook carrier is secured to the end of the shaft and is
provided with a counterweight e. which will serve to countoract all tendency to
vibration or shock. R is the needle which is fixed to the needle carrier or bar P
and receives its motion in the usual way through an arm S pivotted at St. and
actuated by the groove K³ of the cam. K?. As mentioned above the inclination of

page_text: this groove may be considerably reduced by reason of the coupling arrangement as
the motion of the needle bar may be more gradual.
The thread passes from the reel U to the tension U¹ and thence round the
pulley T through the guide T' round the pulley of the tightening mechanism V
again through the guide T¹ round a second pulley T2 to the needle.
The tighteuer V is pivotted at V' and is actuated by the groove K of the
cam K
Referring now to Figures 1-3 and 3' it will be seen that the needle R is at the
lowest point of its stroke the loop is formed and the point of the hook is just
entering the same and the cranks A. A¹ and C. C. with their respective links B B'.
are in the position shewn at Fig: 3¹.
After the first quarter of rotation of the driving shaft the respective parts will
be in the position shewn at Figures 4 and 4' that is to say the hook has taken
the loop and with an accelerated movement has drawn it round the bobbin shuttle
or spool making a half rotation on its axis so that its point is downwards
the needle has withdrawn leaving a sufficient quantity of thread to go round the
bobbin.
Figures 5 and 5' shew the position of the mechanism after the second quarter
of rotation of the driving shaft during which time the hook rotates at the same
speed as the shaft and lets go the loop the needle rises to its highest point
taking up under the influence of the tightening mechanism the excess of thread.
Figures 6 and 61 show the position of the parts at the end of the third quarter
of the rotation of the driving shaft, during which time the speed of the hook
diminishes to one eighth of a rotation the final tightening of the stitch is effected
and the needle commences to descend..
Then during the last quarter rotation of the shaft the hook makes one eighth
of a rotation and regains its point of departure as shewn at Figures 1. 2. 3 and 3'
the needle continues its descent and the new loop is formed ready to be taken by
the hook for the next stitch.
Figures 1 and 2 shew the cam D which operates the feeding mechanism
but this mechanism as well as that for regulating the stitch have no interest
here and have therefore been omitted in order. to leave more clear the essential
parts.
Having now described my Invention of "Improvements in Sewing Machines,"
and explained the manner of carrying the same into effect, I claim:
1. The means herein described for giving a variable speed to the rotary hook of
a Sewing Machine, such means consisting essentially of a driving shaft K and
hook shaft K, placed either in the same axial line or parallel to one another, and
a third shaft H placed on a line parallel to the other two, the three shafts being
coupled together by cranks and connecting links or equivalent means, and operating
substantially as set forth.
2. The combination of the means above described for giving a variable speed to
the rotary hook with a grooved cam of the form indicated for actuating the
needle bar whereby the Machine may be driven at a speed of Two thousand five
hun tred rotations per minute or thereabouts without shocks or vibrations
substantially as set forth.
In witness whereof I the said Auguste Jacques Hurtu bave hereunto set my
hand and seal the twenty first day of February in the year of our Lord Oue
thousand eight hundred and eighty four.