Year: 1895

page_text: Date of Application, 29 h Oct., 1895-4ccepted, 11th Jan., 1896
ALBERT DOUGLAS SMITH, 1013 Olive Street, St. Louis, Mo., U.S.A.,
Gentleman, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention has relation to improvements in bobbin holders and tension
equalizers for sewing machines and consists in the novel arrangement and com-
bination of parts more fully set forth in the Specification and pointed out in the claims.
In the drawings,
Figure 1 is a side elevation of a top of a machine with my improved holder
attached thereto;
Figure 2 is a bottom plan view of the bed plate with my improvement attached ;
Figure 3 is an end view; Figure 4 is a vertical longitudinal section with parts in
normal position; Figure 5 is a similar section with parts in position for ejecting
the bobbin ;
Figure 6 is a plan view of the oscillating or yielding holder;
Figure 7 is a perspective view of the arm for retracting the holder from its
engagement with the bobbin ;
Figure 8 is a sectional view of the bobbin ;
Figure 9 is a detail view of one end of one of the arms of the holder with its
adjustable terminal cam secured thereto; and
Figure 10 is a section on x-x of Figure 9.
The object of my invention is to construct a bobbin holder and tension equalizer
for that class of sewing machines known as the rotating hook type, or the partially
rotating type known as the oscillating type the special purposes of the holder
being to equalize the tension from the bobbin and the take-up at the completion
of each individual stitch; to allow the loop coming from the needle to readily
pass around the bobbin and between it and the holder; to prevent the bobbin
from rotating with the hook carrying the same, at a time previous to the taking up
of the loop from the needle by the looper of the hook, which accidental rotation
is apt to snarl the thread; to reduce the friction between the bobbin and the
rotating hook carrying the same; to dispense, if desirable, with the bobbin case
and proportionately enlarge the bobbin proper. In general, the invention consists
of the ordinary rotating hook carrying the bobbin; of a suitable spring controlled
pivoted holder and tension equalizer disconnected from and independent of the
hook, having one arm whose free end co-operates with and is controlled by a fixed
cam on the hook shaft for intermittently allowing the loop from the needle to pass
around the bobbin and between it and the holder, and a second arm of proper
contour for directly embracing the outer or exposed side of the bobbin, and
holding the same within the hook against the rounded inner end of the hook
shaft; of a suitable spring for restoring the holder arm to its normal position
against the bobbiu after the loop has passed the point just referred to, and the
cam on the hook shaft has ceased its action upon the free end of the first arm of
the holder; of a suitable sliding plate on the working surface of the bed plate
carrying a hooked arm for grasping the holder arm and retracting the same from
out of engagement with the bobbin, thereby leaving the latter loose in its hook;
of a suitable tripping lever pivoted to the bottom of the sliding plate, the end of
which lever is adapted to strike the loose bobbin and eject the bobbin from its
position in the hook; and of other details now to be described.

page_text: Referring to the drawings, 1 represents the bed plate and 2 the hook shaft
mounted on the inner side of the same, and 3 the rotating hook secured to the
outer end thereof. The end of the shaft 2 projects a suitable distance into the
interior of the hook, the said projecting end 4 being rounded off and forming on
one side of the hook a smooth bearing for the concave depression 5 of the
bobbin 6. By this construction the bobbin is held at a suitable distance from the
inner wall of the hook, thereby reducing the contact surface between the bobbin
and the hook, and hence reducing the friction between the two. When therefore
the rotating hook is turning on its shaft, the tendency of the bobbin to rotate with
it (especially before the looper of the hook takes up the loop coming from the
needle) is reduced to a minimum and there is little or no liability for the thread
snarling.
The new holder for retaining the bobbin within the hook while the latter is
rotating, may be described as follows: Pivoted preferably to a guide plate 7 which
guides the oscillating bar 8 that controls the feed mechanism (all these parts being
old) is a holder having a lever arm 9 of suitable curvature, the free cam or
rounded end thereof co-operating with a lateral cam surface of the cam 10 located
on the hook shaft and whose radial cam surface operates the feed mechanism as is
well known. With every revolution of the hook shaft, the lateral cam surface of
the cam 10 will oscillate the arm 9 about its pivotal point on the plate 7, the said
arm being retracted to its normal position by the coiled spring 11 having one end
secured to a convenient point along the arm 9, and its opposite end to a convenient
point along the bottom of the bed plate, the tension of the said spring being
regulated and controlled by a thumb nut 12 on a screw-threaded bolt 13 to which
the opposite end of the spring is actually secured. The end of the lever arm 9
is provided with an adjustable cam 14, said cam being secured by a screw-threaded
bolt 15 as best shown in Figure 10. The cam 14 is first accurately adjusted with
respect to the degree of oscillation to be given to the arm 9 and then secured by
the bolt 15.
The bobbin holder has a second arm 16 extending at a suitable angle from the
pivotal point of the arm 9, and parallel to the outer face of the bobbin when
located in its hook, and extending a sufficient distance beyond the hook as best
seen in Fig. 3. Extending below the arm 16 and forming a part thereof and
approximately opposite the middle of the diameter of the hook are depending
forks 17, and extending in the opposite direction substantially at right angles to
the arm 16 is a guide strip 18, all these parts taken collectively serving as a
holder for the outer wall or face of the bobbin and the guide strip 18 serving
additionally as a guide for the bobbin while the latter is being inserted into the
hook. To prevent the bobbin from falling through and out of the hook when the
bobbin holder is withdrawn or retracted from the bobbin as subsequently to be
explained, I provide two additional guide prongs 19 on either side of the forks 17
and secured to any convenient point along the bottom of the bed plate. To release
the bobbin from its holder and tilt or retract the latter out of engagement with
the bobbin, so as to leave the bobbin in position to be ejected by the tripping
lever, provide the following mechanism: Secured to the under side of the
lateral sliding plate 20 on top of the bed plate adjacent to the feed mechanism, is
a hooked arm 21, the hooked end being adapted to seize the outer projecting eud
of the arm 16 of the holder as the plate 20 to which the hooked arm is secured
is pulled outwardly, thus tilting the holder about its pivotal point on the plate 7,
and retracting the arm 16, forks 17, strip 18 out of engagement with the
bobbin, leaving the latter loose in the rotating hook, as best seen in Figure 5. The
bobbin can now be ejected from the book if properly struck from below. This
I accomplish by the following mechanism: Pivoted to the under surface of the
plate 20 at a convenient point, is a spring-controlled tripping lever 22 operated by
a striking disk 23 at the end of the short outwardly projecting arm 24 of the
tripping mechanism. The relative position of the tripping lever 22 is between the
forks 17, and when the plate 20 is withdrawn as above indicated, the free end of

page_text: the tripping lever is brought directly under the lower edge of the loose bobbin.
It is apparent that if the disk 23 is suddenly struck by the hand of the operator,
it will trip the free end of the lever 22 upwardly, striking the bobbin and throwing
it out from its hook on to the bed plate. The striking disk 23 is semi-circular,
and when the parts are in their normal position, the straight edge of the disk
meets the outer edge of the plate 20, and the two surfaces are thus continuous.
After the lever 22 has been tripped, it is restored to its normal position by the
coiled spring 25 wound about and having one end secured to a pin 26, and the
opposite end operating and bracing against the lever 22. To prevent the lever 22
being accidentally tripped when the plate 20 is closed and while the machine is
running, I secure a guard arm 27 to the bottom of the bed plate, the curved outer
end thereof abutting against the under surface of the striking disk 23 when the
parts are closed.
Inasmuch as I avoid the use of a bobbin case with my present invention, it
becomes. necessary to so qualify the construction of the bobbin as to prevent the
loop around it, passing accidentally between the two walls of the same.
To ensure
the passage of the loop around the bobbin therefore, 1 give the outer wall 28 a
greater or more pronounced convexity along the edge thereof than the convexity
given to the inner wall 29.
The operation of the rotating hook with its contained bobbin, and the manner of
forming the stitch is old and well known and need not be here described. It is to
be understood of course that in the formation of the stitch the loop taken up by
the hook passes around the outside of the bobbin (or bobbin case when the latter
is used) and between the bobbin (or case) and the holder, and where a holder is
used. (as it is invariably), the tension from the bobbin is constant during the entire
formation of the stitch, the tension being made by the elastic spring usually secured
to the bobbin and through and around which the thread from the bobbin passes, as
it unwinds from the latter. Where the tension from the bobbin is constant, and
that from the take-up is not so, or is not effected until at the close of the stitch,
thin goods are apt to pucker by reason of this inconstancy of tension. By my
improvement, the moment the loop is cast off from the hook to pass around the
bobbin, the cam 10 on the hook shaft is in position to engage the cam 14 on the
arm 9, tilting the same and consequently the lever 16 with its attachments which
constitute the holder proper, away from the bobbin sufficiently to allow the loop to
readily pass around the bobbin and between it and the holder. The holder thus
yields or tilts under the action of the cams at the proper moment to ensure the
easy passage of the loop around the bobbin. Further revolution of the hook shaft
permits the holder to again resume its normal position and seize the bobbin, by
the action of the spring 11, and thus ensure the tension from the bobbin that is
desirable at the completion of a stitch. At this moment, however, the take-up
device has about reached the limit of its extreme upward stroke and tightened the
thread coming from the needle; so that the tension with my improvement is
simultaneous both above and below, and the puckering of the goods is avoided.
The holder in the present case therefore is not fixed or stationary, but oscillating
or yielding, allowing with each oscillation, the loop to freely pass around the
bobbin, and, toward the end of the formation of each stitch, scizes the bobbin and
thus ensures the simultaneous tension from the bobbin and from the take up. The
holder as constructed too, prevents momentarily the bobbin from rotating with the
hook (a danger common with stationary holders, where the distance between
the holder and bobbin is constant and where the bobbin is not released at the
moment of the passage of the loop around the same); by the action of the yielding
spring 11, the arm 16 is held against the bobbin which rotates about the terminal
rounded end of the hook shaft, and thus the inside of the bobbin contacts only
with this rounded end, thereby reducing the friction between that side of the
bobbin and the hook, to a minimum, and the liability of the bobbin turning with
the hook at the same velocity as the hook, disappears. The manner of ejecting
the bobbin has already been described and need not be again reviewed.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is,
1. In a sewing machine, a rotating hook, a bobbin loosely carried by the hook,
a, tilting holder pivoted to the stationary part of the machine and normally in
direct contact with the bobbin during a portion of the revolution of the hook.
means operated by the running mechanism of the machine for wholly disengaging
the holder from the bobbin during the passage of the loop around the bobbin, an
independent sliding plate normally out of contact with the holder, and intermediato
connecting mechanism carried by the plate and located to tilt the holder about its
.fixed pivotal point, out of contact with the bobbin upon the withdrawal of said
plate from its normal position, substantially as set forth.
2. In a sewing machine, a sliding plate, a spring-controlled tripping lever for
forcibly ejecting the bobbin pivoted to said plate, a striking disk or plate at the
end of the tripping lever, an arm carried by the plate, a rotating hook, a bobbin
carried by the same, a yielding tilting holder, said arm being located to tilt said
holder out of contact with the bobbin upon the withdrawal of said plate from its
normal position, substantially as set forth.
3. In a sewing machine, a suitable hook adapted to loosely contain a bobbin, a
bobbin holder having an arm adapted to be brought in direct contact with one side
of the bobbin, a second arm forming a part of said holder, a cam on the hook
shaft adapted to rotate therewith, an adjustable cam secured to or carried by the
-second arm of the holder and co-operating directly with the cam on the hook shaft,
suitable forks securing or forming a part of the first arm, and an additional guide
strip on said first arm, substantially as set forth.
4. In a sewing machine, a suitable hook, a bobbin carried by the same, a yielding
holder adapted to alternately directly engage with and disengage from the bobbin,
.a. sliding plate on the bed plate of the machine, a hooked arm carried by the
sliding plate and adapted to seize the holder and tilt the same out of engagement
with the bobbin upon withdrawal of the sliding plate from its normal position, a
tripping lever pivoted to the sliding plate, the free end of the said lever adapted
to be brought in engagement with the bobbin and forcibly eject the same from the
hook upon withdrawal of the sliding plate and consequent tilting of the holder,
and additional means for preventing the tripping of the tripping lever when the
slide plate is in its closed position, substantially as set forth.
Dated this 29th day of October 1895.
For the Applicant,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.