U.S. patent number 3,698,333 [Application Number 05/150,608] was granted by the patent office on 1972-10-17 for rotating shuttle drive mechanisms.
This patent grant is currently assigned to The Singer Company. Invention is credited to Stanley J. Ketterer.
United States Patent |
3,698,333 |
Ketterer |
October 17, 1972 |
ROTATING SHUTTLE DRIVE MECHANISMS
Abstract
A drive mechanism for a rotary shuttle in which the shuttle is
operatively connected to a rotary actuator by means of a pinion
extending therebetween and serving as a radial driving key. In
order to pass needle thread loops between the shuttle and the
pinion, the pinion is turned slowly about its own axis during
rotation of the shuttle so that the thread loops will be carried in
one of the radial indentations between adjacent pinion teeth.
Inventors: |
Ketterer; Stanley J.
(Jamesburg, NJ) |
Assignee: |
The Singer Company (New York,
NY)
|
Family
ID: |
22535280 |
Appl.
No.: |
05/150,608 |
Filed: |
June 7, 1971 |
Current U.S.
Class: |
112/189 |
Current CPC
Class: |
D05B
57/14 (20130101) |
Current International
Class: |
D05B
57/14 (20060101); D05B 57/00 (20060101); D05b
057/08 () |
Field of
Search: |
;112/189,190,191,193,185,181,184 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hunter; H. Hampton
Claims
Having set forth the nature of this invention, what is claimed
herein is:
1. In a lockstitch sewing machine having an endwise reciprocatory
thread carrying needle and a circularly moving shuttle having means
for carrying a supply of locking thread therein, said shuttle being
adapted to pass completely through successive loops of needle
thread to concatenate said needle and locking threads into
lockstitches, a drive mechanism for imparting circular movement to
said shuttle comprising, stationary support means on said sewing
machine formed with a raceway constraining said shuttle for
movement in a circular path, a shuttle driving member supported for
circular movement in spaced relation to said stationary support
means, a disc rotatably supported on said shuttle driving member on
an axis perpendicular to the axis of circular movement of said
shuttle member, said shuttle being formed with a radial slot
embracing the periphery of said disc, said disc periphery being
formed with a radial thread accommodating indentation, and means
operatively connected to said disc and effective to impart turning
movement to said disc about said disc axis at a rate not greater
than one revolution of said disc during each revolution of said
shuttle driving member.
2. A shuttle drive mechanism as set forth in claim 1 in which said
disc comprises a pinion having evenly spaced teeth defining said
radial thread accommodating indentation therebetween.
3. A shuttle drive mechanism as set forth in claim 2 in which said
means effective to impart turning movement to said disc comprises a
screw carried by said stationary support means and arranged in mesh
with said pinion teeth.
4. A shuttle drive mechanism as set forth in claim 3 in which the
pitch of said screw is so related to the pitch of the teeth of said
pinion that at least one thread accommodating indentation between
pinion teeth will be shifted completely through said shuttle slot
during each revolution of said shuttle.
Description
BACKGROUND OF THE INVENTION
A shuttle as is well known in the sewing machine art, is a
lockstitch forming loop taker which accommodates a supply of
locking thread, usually on a bobbin stored in the shuttle and forms
lockstitches by passing bodily through each successive needle
thread loop, thereby concatenating the needle and locking thread
into lockstitches. In the process of stitch formation using a
shuttle, therefore, each loop of needle thread must pass between
the shuttle and the mechanism of the machine for imparting movement
to the shuttle. Where the shuttle is oscillated back and forth
during each stitch forming cycle, the reversal of direction of the
shuttle drive elements naturally provides clearance for the needle
thread loops to pass therebetween. Where the shuttle is to be
rotated continuously in one direction, however, a gap or clearance
for passage of the thread will not ordinarily be formed during the
shuttle operation. Where sewing speeds are low it is possible to
rely upon the tension in the needle thread to pull the needle
thread loops between the driver of the shuttle, but as in
industrial sewing machines, where the sewing speeds become
appreciable, the driving forces necessary to rotate the shuttle
become sufficiently large that the sewing threads cannot simply be
pulled therebetween without serious risk of thread breakage and
adverse influence on the stitch process.
Prior known rotary shuttle drive mechanisms in which provision has
been made to provide an opening through which needle thread loops
might be passed between the shuttle and the shuttle driver have
involved elements required to be imparted harsh motions or to be
driven at high speeds equal to or many times greater than the speed
of operation of the shuttle. Such prior rotary shuttle drive
mechanisms have tended to be noisy and have tended to wear
abnormally high rates.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a drive mechanism for
a rotary shuttle in which a connection element arranged between the
shuttle and the shuttle driver moves bodily at the same speed as
the shuttle driver and in addition, is driven at a fraction of the
speed of the shuttle in order to move a thread accommodating
indentation relatively to the shuttle at a speed just sufficient to
pass needle thread loops therebetween during the stitch formation
operation. The above object is attained by the provision of a
keying element between the shuttle driver and the shuttle which
takes the form of a pinion of which the teeth mesh with a
stationary screw formed in the shuttle housing of the sewing
machine. The pitch of the pinion teeth and of the stationary screw
with which they mesh is chosen to provide for rotation of the
pinion about its own axis at a fraction of the speed of rotation of
the shuttle so that a radial indentation in the pinion between the
teeth thereof may accommodate and shift each needle thread loop
which is seized by the shuttle through the shuttle driving
connections.
DESCRIPTION OF THE DRAWINGS
With the above and other objects and advantages in view of this
invention will be described hereinbelow, with reference to the
accompanying drawings of a preferred embodiment in which:
FIG. 1 represents an end elevational view of a sewing machine
having a shuttle driving mechanism of my invention applied
thereto,
FIG. 2 is an enlarged vertical cross-sectional view taken
substantially along line 2--2 of FIG. 1 through the longitudinal
axis of shuttle rotation,
FIG. 3 is an exploded perspective view of the shuttle housing, the
shuttle and the shuttle driving mechanism of this invention,
FIGS. 4, 5, 6 and 7 represent elevational views of the face of the
shuttle each taken at a different position of rotation of the
shuttle during a typical stitch forming cycle and including a
representation of the needle thread loop being manipulated by the
shuttle, and
FIG. 8 is a cross-sectional view taken substantially along line
8--8 of FIG. 6 illustrating the needle thread loop as it is passing
between the shuttle and the shuttle driving mechanism.
Referring to the drawings, this invention is illustrated as
embodied in a conventionally organized sewing machine including a
frame having a work supporting bed 11 from which rises a standard
12 carrying a bracket arm 13 overhanging the bed. A thread carrying
needle 14 is secured to a needle bar 15 supported in the bracket
arm and driven by a mechanism (not shown) in timed relation with a
rotary bed shaft 16 illustrated in FIGS. 2 and 3. The bed shaft is
preferably imparted one revolution for each cycle of reciprocation
of the needle. As illustrated in FIG. 1 a needle thread take-up
member 17 and a needle thread tension device 18 are carried by the
bracket arm and serve in a conventional manner to influence the
needle thread which extends to the thread carrying needle 14. The
needle 14 reciprocates endwise through a needle aperture 20 in a
throat plate 21 on the work supporting bed 11 of the sewing machine
and cooperates beneath the throat plate with a shuttle indicated
generally at 22. Also arranged beneath the throat plate is a work
feed dog 23 which may be carried by a feed bar 24 which is imparted
rising and falling movements by a feed lift rock shaft 25 by way of
a rock arm 26 and a link 27, and to which feed advance and return
movements are imparted by a rock frame 28 fast on a feed rock
advance. The feed dog 23 works through slots 30 in the throat plate
in opposition to a presser device 31 supported on a presser bar 32
carried in the bracket arm 13.
Referring to FIGS. 2 and 3, the shuttle 22 is preferably formed
with a circular bearing rib 40 which extends from a flat rear face
41. The shuttle is formed with a body portion 42 provided in the
front face with a bobbin accommodating cavity 43. As shown in FIG.
8, a central stud 44 may be formed from the flat rear face 41 into
the bobbin accommodating cavity 43. A flanged bobbin seat 45 is
retained on the stud 44 by a screw 46 which can adjust the pressure
between the flanged bobbin seat and a friction washer 47 which is
arranged against the flat rear face 41 of the bobbin. The flanged
bobbin seat is thus rotatable on the seat 44, subject to frictional
resistance to turning which may be regulated by the screw 46. An
annular friction ring 48 set into the flanged bobbin seat 45
constrains a bobbin 49 on the bobbin seat 45. Thread which is wound
on the bobbin will therefore, have a tension applied thereto as the
thread is withdrawn. It will be understood that the above described
means for accommodating a bobbin in the shuttle and for applying a
tension to a locking thread wound on the bobbin does not form a
direct part of this invention and any other suitable bobbin housing
and bobbin thread tensioning means may be used with the present
invention.
The bearing rib 40 of the thread is formed with a gap 59 defining
at one side a needle loop seizing beak 60 adapted as shown in FIG.
4 to seize and to distend loops of needle thread N during operation
of the sewing machine. At the opposite side of the gap 59, the
shuttle bearing rib is formed with a needle thread loop detaining
finger 61 which serves as shown in FIG. 7 to engage each needle
thread loop N after it has been passed completely about the shuttle
to prevent the loop of thread from flying out of control as it is
drawn into the work being stitched.
Referring to FIGS. 2 and 3, a shuttle housing block 70 is fixed in
the sewing machine bed and formed with a bearing surface 71 for the
bed shaft 16. The bearing surface 71 opens upon a cavity 72 which
is provided at the mouth thereof with a raceway 73 in which the
shuttle bearing rib 40 is journaled for rotation. A semi-circular
shuttle retainer 74 and a resilient fastening clip 75 are secured
by a fastening screw 76 on the exposed face 77 of the shuttle
housing block 70 to constrain the shuttle 22 in the raceway 73.
As shown in FIG. 2, the bed shaft 16 protrudes into the cavity 72
in the shuttle housing block and in the cavity 72 a shuttle driving
block 78 is secured to the bed shaft 16 by a set screw 79 and by a
drift pin 79'. The shuttle driving block is formed with a radial
slot 80 in which a pinion 81 is constrained. The pinion is
journaled in the shuttle driving block on an axle pin 82 secured
therein, so that while it may turn on its own axis in the shuttle
driving block, the pinion will be snugly supported against tilting
by the closely fitting radial slot 80.
As shown in FIG. 2, the pinion is carried in the shuttle driving
block with the pinion teeth 83 protruding both radially and axially
from the shuttle driving block 78. Radially of the shuttle driving
block, the pinion teeth 83 mesh with a stationary screw 84, formed
internally of the cavity 72 in the shuttle housing block. Axially
of the shuttle driving block, the teeth 83 of the pinion extend
into a radial slot 85 formed in the flat rear face 41 of the
shuttle. Preferably, as shown in FIG. 8, the pinion teeth 83 extend
radially only partially into the radial slot 85 and the rear face
of the shuttle so that a space is provided in the radial
indentations 86 between the pinion teeth 83 for accommodation of
needle thread loops as the needle thread loops pass between the
shuttle and the pinion during each stitch forming operation.
Preferably, the pitch of the pinion teeth 83 and the pitch of the
screw threads 84 are chosen so as to provide for a speed of
rotation of the pinion amounting to only a small fraction of the
speed of rotation of the shuttle. This low velocity rotation of the
pinion about its own axis is amply sufficient to pass needle thread
loops between the shuttle of the shuttle driver, and the low speed
of rotation of the pinion reduces the wear and the noise incident
to the operation of a machine having this invention applied
thereto. With machine speeds of greater than 5,000 stitch forming
cycles per minute, successful passage of needle thread loops past
the shuttle drive has been obtained with pinion speeds of
one-fourth the speed of rotation of the shuttle. It will be
appreciated that the speed of rotation of the pinion about its own
axis may be varied either by changing the size of the pinion 81 or
the pitch of the screw 84.
* * * * *