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Патент USA US3026845

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March 27, 1962
R. H. HALL
3,026,835
PNEUMATIC NEEDLE-BAR POSITIONEIR FOR SEWING MACHINES
Filed March 31, 1958
5 Sheets-Sheet l
INVENTOR.‘
Richard H.Ha1l,
AT TOENEY.’
March 27, 1962
R. H. HALL
3,026,835
PNEUMATIC NEEDLE‘BAR POSITIONER FOR SEWING MACHINES
Filed March 31, 1958
5 Sheets-Sheet 2
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RicharAH. Hall,
BY wax, ?aw
ATTORNEY
March 27, 1962
R H. HALL
3,026,835
PNEUMATIC NEEDLE-BAR POSITIONER FOR SEWING MACHINES
Filed March 31, 1958
5 Sheets-Sheet 3
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INVENTOR.’
Rlchard H?all,
BY WW @LJM
AT TORNFYT
United States atent
3,026,835
Patented Mar. 27, 1932
1
2
Member 13 carries the usual need bar (not shown) and
3,026,835
PNEUMATIC NEEDLE-BAR POSHTIONER FOR
its rotating driving shaft 15. Shaft 15 is driven by
V~belt 1'7 and its cooperating pulley 19. Pulley 19 is
SEWING MACHINES
Richard H. Hall, 3907 Estes Road, Nashville, Tenn.
Filed Mar. 31, 1958, Ser. No. 725,021
8 Claims. (Cl. 112-221)
'drivingly connected to shaft 15 by an automatically op
erated clutch mechanism which permits the pulley 19 to
free-wheel when the needle positioner is in operation.
The automatic clutch mechanism comprises the hand
This invention relates to a pneumatic needle-bar posi
wheel 21 which is keyed to the shaft 15 for limited axial
tioner for sewing machines.
movement thereon. A compression spring 23 acting be
More particularly the invention pertains to pneumati 10 tween
?ange abutment 15a ‘and washer 21a normally
cally operated means for positively positioning the needle
forces
wheel
21 to the left (FIGS. 2 and 3) so as to grip
bar of a sewing machine in a predetermined position
the pulley 19 between the two clutch disks 25 and 26.v
(usually up but selectively down if preferred) at the end
Disk 26 is held against axial movement away from pulley
of each sewing operation involving raising of the presser
1? by the ?ange 27 ?xed to the extension 15b of the
foot, said means being constructed and arranged to for 15 hand-wheel shaft 15 by its integral hub 27a upon which
wardly rotate the shaft reciprocating the needle bar thru
the pulley 19 free-wheels when declutched.
an angle approaching 350 deg. (or backwardly about 10
The pneumatic operator comprises the shaft extension
deg.) to prevent undesirable slack in the threads (as oc
15b rigidly coupled to shaft 15 ‘and in accurate aline
curs in needle positioners which produce half of the time
ment therewith, and the pneumatic cylinder 29 concen
backward rotations up to 180 deg).
20 trically mounted there around. Cylinder 29 is provided
This disclosure is an improvement over applicant’s '
with an enlarged extension sleeve 29a slidably mounted
previously ?led application S.N. 610,362, ?led Septem
in the support block 31 and keyed thereto at 31a. Block
ber 17, 1956, for “Means Responsive to Sewing-Machine
31 is formed of two parts connected by screws 31b.
Presser-Foot Operation for Work-Control Positioning of
Block 31 is accurately and adjustably positioned and held
Needle Bar,” the disclosure of which is hereby included 25 against rotation by the rigid structure consisting of screws
herein by reference. 'Its purposes are fundamentally the
32 and 33 adjustably connected to block 34 by nuts 34',
same as those of said prior application, namely automatic
the articulated arm 35, vand the anchor post 36 ?xed to
positive positioning of the needle in predetermined posi
the base portion 11.
tion relative to the work when the presser foot is raised
The ?exible hose 3'7 conducts compressed air to cyl-'
30
and for the reasons stated therein, but it advantageous
inder
29. Air enters thru passage 39a in the cylinder
ly differs therefrom in providing pneumatic operating
head 39. A pair of 0 rings 40 and 41 of resilient ma
means in place of knee-powered means and in very de
terial seal the joints between the head and the cylinder
sirably providing up to 350‘ deg. forward rotation of the
29 and between the rotating shaft 15b and its embracing
needle-bar-driving shaft, thus leaving only an occasional
bore thru head 39. A U-gasket 43 of resilient material
(1 in 36) backward rotation of 10 deg. or less, which
forms the sealing portion of the annular piston com
does not produce an objectionable thread slackening, as
pleted by the ?ange 45a on the sleeve-cam 45. A spring
compared with the 180 deg. backward rotation of prior
art needle-bar posiltioners.
47, compressed between ?ange 45a and guide ring 49
‘
for the sleeve-cam 45, normally holds the parts in their
FIG. 2 positions. When compressed air enters port 39a
It is accordingly the principal object of this invention
to provide a needle-bar positioner in which thread
it moves sleevecam 45 to the left so that its 350 deg.
heiical edge 45b engages a roller-bearing cam follower
51 to rotate the shaft 15-—15b thru an angle up to about
slackening (backward) movement thereof is reduced to
a minimum both in frequency and in amount of move
ment.
.
It is a further object to provide such a device with
pneumatic operating means.
350 deg. in the forward direction. A pin 53 (?xed to
45
face 45c of the cam 45 and prevents the free-?oating
sleeve cam 45 from being rotated by cam-follower
It is a further object to provide such a device with
automatic clutch means for disconnecting the belt-driven
exerted counter force. Follower 51 is mounted on post
51a screwed into a radial bore in shaft 15b. The outer
pulley from the hand-wheel shaft.
These and other objects and advantages of the inven
end of shaft 15b is journaled in the bearing sleeve 55
tion will become apparent as the following detailed de
mounted on the head 57 ?xed to the end of cylinder ex
scription proceeds.
tension 29a.
In the drawings:
-
. If the par-ts are in the positions of FIG. 2 when- the
FIG. 1 is a perspective view of a preferred embodi
ment of the invention.
guide ring 49) is engageable against the straight-edged
air pressure is applied, the sleeve 45 will not move fol
"
55 lower 51 since its wedge-shaped end will not be forced
FIG. 2‘is a front elevational view of the unenergized
between it and pin '53. Rather, the‘ sleeve 45 will be
moved away from pin 53 by follower 51 until pin 53 is
engaged by surface 45b near the socket 45d. Then the
device of FIG. 1 in partial axial section.
FIG. 3 is a view similar to FIG. 2 showing the pants
pneumatically moved to needle-positioning positions.
FIG. 4 is a view, similar to FIG. 2 of a modi?ed con
sleeve 45 will be rotated backwardly and will move the
shaft, thru follower 51, about 10 deg. backwardly (which
struction.
will not move the needle bar appreciably, since it is in
FIG. 5 is a perspective view of the automatic air valve.
this case adjacent the bottom of its stroke).
FIG. 6 is an enlarged elevational view of the valve in
Since cylinder 2.9-—29a is mounted in block 31 for
vertical section taken on the plane of the axes of the
slight axial movement, air pressure causes the same to
tapped air inlet and outlet passages.
65 move to the right (FIGS. 2 and 3) thus producing clutch
operating engagement of pins 59 by the head 39. Pins
FIG. 7 is a view similar to FIG. 6 but showing the
59 are slidably received in bores thru the hub 27a.
valve parts in device-operating positions.
The automatic control mechanism is illustrated in FIGS.
With reference now to FIGS. 1 and 5, the numeral 11
60
5~7. Said mechanism comprises a clamp 61 consisting
designates the base of a conventional factory-type sewing
machine which rests ‘upon machine board 12 and from 70 of a pair of plates 61a and 61b having mating semi
cylindrical channels in their opposed faces which close
which rises the overlying hollow head member 13.
upon and grip the conventional presser-foot operating
3,026,835
3
4
the needle of a sewing machine in a preselected stroke
rod 63 when they are drawn together by screws (not
visible) the heads of which lie against the far side of
plate 61a. The lower half of plate 61b carries the valve
block 65 fastened thereto by the screw 66. Compressed
air is fed to block 65 by the hose 67 and conventional
coupling elements 68-70. A valve plunger 71 has a pro
position, comprising: a cam member and a cam-follower
member having normally disengaged surfaces providing
when said surfaces are engaged relative rotation in one
direction therebetween closely approaching 360", means
operatively connecting one of said members for rotation
with the needle-bar drive shaft of a sewing machine,
and power-applying means for operating the other of said
members into engagement with said one member to posi
truding operator 71a engageable against the top of base
11. when the presser-foot operating rod 63 is depressed
to‘raise the presser foot. This operation raises valve disk
71b away from the sealing O-ring 72 to permit com 10 tion said needle bar in said preselected position by turn
ing said needle-bar drive shaft in most instances in a
pressed air to ?ow into chamber 65a and thence thru
forward direction to minimize frequency of occurrence
couplers 73—75 into the cylinder 29. When the rod 63
and amount of undesirable backward movement of said
is raised to lower the presser-foot into sewing position,
shaft.
valve stem 71 drops to its FIG. 6 position shutting off the
supply of compressed air and discharging that in the 15
cylinder 29 thru ports 65b so that the needle-bar-position
ing cam 45 can be returned to its inoperative position
of FIG. 2 by spring 47.
In the modi?cation of FIG. 4, simpli?ed by the omis
sion of the clutch mechanism of the previously described
species, the arrangement and actions of the parts are re
versed. The shorter shaft extension 15b’ supports the
near end of cylinder 29' thru its head 58 attached thereto
by screws 58’. A ?ange 15c’ engages a thrust bearing
59' backed up by the collar portion of head 58 to prevent
undue thrust against shaft 15b when the cam 45' is pneu
matically thrust against the follower 51’. The outer end
of shaft 15b’ is journaled in a bore 57a’ in the end of
member 57’, the left end of which is enlarged to form
the other cylinder head and is attached to cylinder 29'
by screws 60'.
The cam 45' freely slides over the outer surface of
member 57’ and is held against unlimited rotation thereon
by' the screw pin 53’ which also helps locate and support
2. Structure according to claim 1, said power-applying
means being coupled to presser-foot-operating mechanism
of said sewing machine for automatic control thereof in
response to operation of said presser foot.
3. Structure according to claim 2, said power-applying
means being a pneumatic cylinder and said coupling
means being a valve mounted on the conventional operat~
ing rod for said presser foot and operated in response
to movement of said rod.
4. Structure according to claim 1, said power-applying
' means being a pneumatic cylinder alined with an axial
extension of said needle-bar drive shaft, said cam member
being a sleeve operated by the piston of said cylinder,
and said cam-follower member being a post mounted on
said axial extension.
5. Structure according to claim 4, said sleeve having a
highly pitched helical edge engageable with said cam
follower and having a circumferential extent approach
ing 360°.
6. Structure according to claim 5, said cam member
the outer‘cam-guiding ring 49’ and the centrally located 35 being free-?oating in said cylinder and said cylinder hav
ing a ?xed second cam follower engageable- against a
end of member 57'. A spring 47’ compressed between
straight edge on said sleeve to limit its rotation within
the ?ange 45a’ and guide ring 49' normally holds the
said
cylinder.
parts intheir FIG; 4 positions. The cylinder 29' is sup
7. Structure according to claim 1 and additionally com
ported by means equivalent to the parts 31—36 previously
prising clutch means‘ automatically operated by operation
described but not slidable therein since the clutch-operat
of said power-applying for discontinuing the drive between
ing movement of the cylinder is not needed in this species.
the power supply for said sewing machine and said needle
Bore 570' is an oiling port.
bar drive‘ shaft upon operation of said positioning means.
Compressed air enters cylinder 29’ thru a port 57b’
8. Structure according to claim 7, said clutch means
connected by couplers 37a’ and 37b’ to hose 37’, which 45
comprising
at least one friction member compressed be
in turn is connected to an automatic valve, such as 61—75
tween the driving pulley for said needle-bar drive shaft
previously described. The entering air forces the U
and means operable by movement of said power-applying
gasket 43’ against cam ?ange 45a’ to rotate the'shaft 15b’
means, the latter being a pneumatic cylinder alined with
by engaging the follower 51’ and pin '53’ as in the ?rst
said shaft and mounted for slight reactive longitudinal
described species.
While I have described a preferred embodiment of my
invention it is to be understood that many changes can be
50
made in the size, shape, composition and arrangements
of the partsiwithout departing from the spirit of the
invention. asde?ned by the subjoined claims. For ex 55
amples, the cam-thrusting means could be solenoid or
human-powered (.by knee, hand, foot,‘ etc.); or a manual
ly or foot-operated switch or valve could be substituted
movement during energization.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,181,363
1,470,687
Anschutz et al. ________ __ May 2, 1916
Clarke _______________ __ Oct. 16, 1923
375,597
France __.._.' __________ __ May 17', 1907
FOREIGN PATENTS
for the automatic valve disclosed. .
Having thus described my invention, I claim:
. 1. Means for positioning the needle bar and thereby
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