Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
BACKGROUND OF THE INVENTION
Ornamental stitching machines are known in
which pattern information is extracted from an electronic
memory storage means to a predetermined time during each
stitch forming cycle when information pertinent to the
placement of the next succeeding stitch is extracted from
the memory storage means and applied to the electromagnetic
actuator. If a different pattern is selected after this
predetermined time in the cycle, such known sewing machine
would none-the-less be committed to placement of the first
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stitch after such selection in accordance with data extracted
from the replaced pattern. The result may be a highly notice-
able incongruous stitch at the beginning of the pattern of
stitches which would detract from the aesthetic appearance
of the resulting stitched seam.
It is an object of this invention to prevent
the carry over of a stitch derived from a previously selected
pattern when a new pattern selection is made in a sewing
-~ machine utilizing an electromagnetically influenced actuator
for controlling the stitch pattern. This object may be
attained by employing a skip stitch mechanism for separating -
the needle from the needle actuating mechanism and by
actuating such skip stitch mechanism for one stitch forming ;~
; cycle whenever the pattern selector mechanism is operated.
There exists a wide variety of electromagnetically
influenced actuators capable of dictating the stitch pattern
in a sewing machine and these actuators differ widely as to ~-~
the predetermined time prior to stitch formation at which
pattern data must be supplied. The electromagnetically
in~luenced actuator as disclosed, for instance, in the
U.S. Patent No. 3,812,729, issued May 29, 1974 requires the
data extracted from the memory storage means to be applied
practically a full stitch forming cycle prior to the
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placement of the stitch to be controlled. Using this type
of actuator, therefore, the skip stitch mechanism would be
utilized whenever the pattern selector mechanism is operated
regardless of when during the stitch forming cvcle the
pattern selection was effected. Other electrically influenced
actuators are known, however, in ~hich data from the memory
storage means need be applied
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to the actuator only immediately preceding the descent of the
needle prior to each stitch forming cycle. When such other
actuators are utilized therefore, actuation of the skip stitch
mechanism is not required if pattern selection is made auring
the upstroke of the needle, and in fact use of the skip stitch
mechanism under these circumstances would serve only to delay
sewing of the newly selected stitch,pattern. It is an object
of this invention to provide a means for effecting operation
of the skip stitch mechanism in response to pattern selection
only during that interval during each stitch for~ing cycle
when the electromagnetically influenced actuator is committed
to operation in response to data supplied from the old stitch
pattern which is being replaced. This object is attained by
a gating arrangement interposed in the control system for the
skip stitch mechanism which gating arrangement is opened only
during periods while the electromagnetically influenced actua-
tor is committed to pattern data so that only when pattern
selection is effected during such intervals will the skip
stitch mechanism be operated thereby.
T~e invention, in one aspect, provides a sewing
machine having stitch forming instrumentalities capable of
producing successive stitches in a variety of different stitch
patterns and including a needle, a mechanical actuator for
imparting repetitive stitch forming cycles of operation to
said stitch forming instrumentalities, an electromagnetically
influenced actuator operatively connected to said stitch form-
ing instrumentalities for controlling the stitch pattern pro-
duced thereby, memory storage means for data regulating the
placement of each stitch in a stitch pattern and having the
capacity for the storage of separate data relating to each of
a plurality of different stitch patterns, operator influenced
pattern selection means for rendering effective data stored in
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said memory storage means relating to any selected one of said
plurality of different stitch patterns, a skip stitch mechanism
for separating said mechanical actuator from said needle, and
means responsive to the operation of said pattern selector
means for operating said.skip stitch mechanism for one stitch
forming cycle of said sewing machine.
The invention in a further aspect provides a sewing
machine having stitch forming instrumentalities capable of
producing successive stitches in a variety of different stitch
patterns and including a needle and a loop taker, a mechanical
actuator for imparting repetitive stitch forming cycles of :~
operation to said stitch forming instrumentalities including
endwise reciprocation of said needle into a position for needle
thread loop seizure by said loop taker, an electromagnetically :
influenced actuator operatively connected to said stitch form-
ing instrumentalities for controlling the stitch pattern pro-
duced thereby, memory storage means for data regulating the
placement of each stitch in a stitch pattern and having the
~apacity for the storage of separate data relating to each of
a plurality of different stitch patterns, operator influenced .
pattern selector means for rendering effective data stored in
; said memory storage means relating to any selected one of said ~ :
plurality of different stitch patterns, means rendered effec-
tive by said mechanical actuator at a predetermined position
of said mechanical actuator prior to each work penetration of
said needle for extracting from s~id memory storage means data
.~ pertinent to the placement of the next succeeding stitch in
said selected stitch pattern and for energizing said electro- !i
magnetically influenced actuator in accordance with said ex-
tracted data, a skip stitch mechanism for separating said
mechanical actuator from said needle, and means responsive
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to operation of said pattern selector means during a predeter-
mined interval after extraction of pattern information data
from said memory storage means for operating said skip stitch
mechanism for one stitch forming c~cle of said sewing machine.
The invention in a still further aspect provides
a sewing machine having stitch forming instrumentalitias capable
of concatenating thread into successive stitches in a variety
of different stitch patterns, a mechanical actuator for impart-
ing repetitive cycles of operation to said stitch forming
instrumentalities each cycle including a position in which
thread concatenation becomes irrevocable for the stitch then
being formed, an electromagnetically influenced actuator
operatively connected to said stitch forming instrumentalities
for controlling the stitch pattern produced thereby, memory
storage me ss for data regulating the placement of each stitch
in a stitch pattern and having the capacity for the storage of
separate data relating to each of a plurality of different
.~ stitch patterns, operator influenced pattern selector means
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for rendering effective data stored in said memory storage
means relating to any selected one of said plurality of dif- : :
ferent stitch patterns~ means rendered effective by said :~
; mechanical actuator at a predetermined position of said :
mechanical actuator prior to s~id position in which thread
concatenation becomes irrevocable for extracting from said :
memory storage means data pertinent to the placement of the
next succeeding stitch in sald selected stitch pattern and
for energizing said electromagnetically influenced actuator
in accordance with said extracted data, a skip stitch mechanism
for separating said mechanical actuator from said needle,
and means responsive to operation of said pattern selector
means for a predetermined interval after extraction of said
pattern information data from said memory storage means for
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operating said skip stitch mechanism for one stitch forming
cycle of said sewing machine.
DESCRIPTION OF THE DRAWINGS
This invention may be understood with reference to
the accompanying drawings of a preferred embodiment in which
FIG. 1 is a perspective view of a sewing machine to
which this invention has been applied,
FIG. 2 is an enlarged perspective view of a pulse
generator used with this invention,
FIG. 3 is an enlarged perspective view of a portion
of the needle bar mechanism of the sewing machine of FIG. 1
and including a skip stitch operating means thereon, and
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FIG. 4 is a functional block diagram showing a
portion of an electronic circuit which may be used in carrying
out this invention.
Referring to FIG. 1 of the drawings, a sewing
machine casing 10 is shown in phantom lines including a bed
11, a standard 12 rising from the bed and a bracket arm 13
overhanging the bed. The driving mechanism of the sewing
machine includes an arm shaft 14 and a bed shaft 15 inter-
connected by a timing belt 16 in the standard. A needle 17 is
carried for endwise reciprocation by a needle bar 18 mounted
for lateral jogging movement in a gate 19 in the bracket arm
13. The connections between the arm shaft and the needle bar
for imparting needle reciprocation include a separable
connection indicated generally at 100 which is referred to in
the art as a skip stitch mechanism and which will be described
in greater detail below.
For imparting lateral jogging movement to the needle,
a drive link 25 is pivoted as at 26 to a block 27 arranged
in a.radial guide slot 28 of an oscillating driver 29 forming
a part of an electromechanical actuator indicated generally
at 30 for influencing the lateral jogging or bight. For an
` understanding of the present invention it is sufficient to
understand that the actuator 30 includes the drive shaft 31
- carrying a sprocket 32 engaging the timing belt 16. A
whippletree linkage 33 which is connected to the driver 29 is
shifted alternatively back and forth by the drive shaft 31
and a selective position of the driver within the range of
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drive shaft imparted motion may be maintained during needle
penetration by the selective energization of five solenoids
20, 21, 22, 23 and 24.
Also illustrated in FIG~ 1 is a fragment of a work
feeding mechanism including a feed dog 34 carried by a feed
bar 35. In FIG. 1 the mechanism is illustrated imparting
work transporting movement to the feed dog including the
feed drive shaft 36 driven by gears 37 from the bed shaft, a
cam 38 on the feed drive shaft, a pitman 39 embracing the
cam 38 and connected to reciprocate a slide block 40 in a
slotted feed regulating guideway 41. A link 42 pivotably
connects the pitman 39 with the feed bar 35 so that depending
upon the inclination of the guideway 41, the magnitude and
direction of the feed stroke of the feed dog will be determined.
The inclination of the guideway 41 in the present
invention may be controlled by an electromechanical feed actuator
indicated generally at 43. The actuator 43 may be constructed
similar to the actuator 30 and may include a drive shaft 44 -.
carrying a sprocket 45 engaging the timing belt 16. A~:
~hippletree linkage (not shown) which is shifted alternately
.i back and forth by the drive shaft 44 is connected to a link 46
.. . . .pivoted at 47 to a rock arm 48 carried on a rock shaft 49 :
secured to the guideway 41. A selected position of the whipple- :.
tree linkage, and therefore of the link 46 may be maintained
during the active work feeding stroke by the selective
energization of five solenoids 74, 75, 76, 77 and 78. A dial
88 on the machine bed is provided with a crank pin 89 embraced
by an adjusting link 94 which extends into the feed actuator 43 ~-
to provide for a balance control. Preferably the balance control -.
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provides for a mechanical fine adjustment between the
whippletree linkage connection and the guideway 41 so that
the intended st~tch length and directions can be accurately
attained.
In the preferred embodiment, the bracket arm is
provided with four selector switches 50, 51, 52 and 53 which
are used by the operator to select one of the ornamental
stitch patterns stored in the electronic memory storage
components 91, 92 and 93 or, alternatively, to obtain a straight
stitch. The obtaining of straight stitch pattern is
accomplished by activation of selector switch 50 whereas three
different ornamental stitch patterns may be associated one
with each of the selector switches 51, 52 and 53.
The selection of a pattern by depression of any -
one of the switches 50-53 will give rise to a pulse signal in
the conductor 139 therein for the purpose of resett ng the
`2~address counter each time a selection is made so that the
newly selected pattern will always proceed from a predetermined
beginning. In the present invention, the pulse signal in the
conductor 139 may be used to indicate when any pattern
selection is effected.
Referring to FIGS. 1 and 3, a skip stitch mechanism
100 is shown having a construction as described in the
.5. Patent ~o. 3,320,4a5 issued June 25, 1974. The skip stitch
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manner in which the skip stitch mechanism cooperates withthis invention.
The needle bar 18 has a block 102 secured thereto
by a screw 101. A second block 103 which is freely slidable
on the needle bar 18 includes a stud 104 which is operatively
connected to the conventional needle reciprocating crank
mechanism (not shown) of the sewing machine. When the blocks
102 and 103 are locked together, the needle will be reciprocated
in the usual fashion, and when the blocks 102 and 103 are
unlocked one from the other t~e needle reciprocating drive
will be interrupted. A clutch lever 105 fulcrumed at 106
on the block 102 includes a clutch finger 107 for interlocking
the two blocks 102 and 103 when the finger 107 underlies the
block 103. A tang 108 on the clutch lever 105 is engageable
by one arm 109 of a bell crank 110 pivoted on a fulcrum pin 1~
carried in the block 102. The bell crank 110 includes a second
arm 112 engaged by a vertically shiftable release member 113
which includes an inclined slot 114 embracing a guide pin 115
in the machine frame so that the release member will move
, 20 laterally when elevated and, therefore, when elevated will
interrupt the needle bar reciprocation. A spring 116 arranged
between the fulcrum pin,lll on the block 102 and an arm 117 on
the release member will elevate the needle bar whenever the
i clutch lever 105 is turned to interrupt the needle reciprocation.
A lateral tab 120 on the release member 113 overlies
one arm 121 of a lever 122 having a fulcrum pin 123 carried in
the machine frame and formed with another arm 124 operatively
connected with a solenoid 125. When the solenoid 125 is
energized momentarily, it will influence interruption of needle
' 30 bar reciprocation and will thus cause a stitch to be skipped.
The pulse signal occurring in the conductor 139 whenever a
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pattern selection switch 50-53 is closed, as described in
the referenced U.S. Patent 3,872,808 issued March 2S, 1975,
may be amplified in any conventional manner and utilized
directly to actuate the solenoid 125 whenever a pattern selec-
tion is made, This arrangement will be ideal where actuators
are used in which pattern information is committed well
before the formation of each stitch.
When an actuator is used for pattern stitch infor-
mation which is supplied with pattern information immediately
prior to needle penetration, then a period exists during each
stitch forming cycle before the supply of pattern information
when pattern selection may be effected without the requirement
for skipping the first stitch. In order to avoid needlessly
skipping the first stitch, means are required for distin-
guishing the instant at which pattern information is suppliedand this may be accomplished as will now be described by
resort to a pulse generator unit 143 such as is disclosed in
the U.S. Patent No. 3,815,531 issued June 11, 1974.
As shown in FIG. 2, the unit 143 includes two
separate pulse generators each including a semi-circular
shaped cam 150 and 152, which cams preferably are made of
; magnetic flux conducting material as is the arm shaft to which
. each of the cams is affixed as by screws 148. The cams 150
and 152 each have a variable peripheral circumference including
a large diameter segment 154 and a small diameter segment 156,
each cam being adapted to cooperate with one of a pair of
Hall effect devices 158 and 160,
Each of the ~all effect devices 158 and 160 con-
stitutes a magnetic flux responsive unit which will develop
across the output leads 170, 172 or 170', 172', respectively,
either a low (0.3 volts) or zero voltage in the presence of low
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flux density or a relatively high DC volta~e (+4 volts)
in the presence of a h~gh flux density. The leads 170 and
- 170' provide the common or ground lines so that in effect,
the presence o~ a high voltage in the line 172 and 172'
constitutes the output of the pulse generator unit 143.
A permanent magnet 174 is arranged adjacent to the
Hall effect devices 158 and 160 and a magnetic flux conducting
base member 176 is employed which includes an extension 1~4
which overlaps a circular disc 186, also made of flux conducting
material, on the arm shaft 14.
As long as the large diameter segment 154 of each
cam 150, 152, is positioned opposite the corresponding Hall
effect device 158, or 160, the high voltage will exist in
- the output line 172, or 172', respectively.
With the arm shaft rotating in the direction indicated
by the arrow in FIG. 2, the Hall effect device 160 provides
a pulse corresponding in time with that required for supplying
pattern information for the bightor zigzag motion of the
needle, and for this purpose the large diameter segment 154
of cam 152 is preferably timed to move opposite the Hall effect
device 160 at top dead center of needle reciprocation. The
cam 150 cooperates with the Hall effect device l58 to produce a
~`~ pulse in the line 172 for supplying pattern information for
the feed regulation preferably timed to begin one-quarter
revolution after top dead center, i.e., when the needle begins
penetration of the work and the preceding feed stroke has been
completed.
With the illustrated arrangement, the high voltage
signal in the lines 172 and 172' will both be discontinued
at 270 degrees beyond top dead center and will remain off
until the next succeeding top dead center position, that is,
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from the time the needle leaves the work until top dead
center is reached. With the form ~f this invention presently
being described, pattern cam select~on if made during that
quarter of each stitch forming cycle from 270 degrees to
top dead center will not result in occurrence of a skip stitch,
whereas pattern selection, if made at any other time, will cause
a stitch to be skipped.
A circuit permitting the skip stitch mechanism
to be actuated only when pattern selection is made during
a predetermined portion of each stitch forming cycle will
now be described with reference to the block diagram illustrated
in FIG. 4. In the diagram of FIG. 4, 201, 202 and 203
indicate one shot units having input terminals A and B
and an output terminal Q. Only when the input terminal A
is at a low or off voltage and the input terminal B is
;; at an on or high voltage will an on or high voltage pulse
` be delivered at the output terminal Q.
`- In the description which will follow, an off
- condition in any of the conductors will mean a low
(0.3 volts DC) or zero voltage, and an on condition will
mean a high (+4 volts DC) voltage.
AND gates 301 and 302 are shown in FIG. 4, as well
as OR gates 401 and 402 and a NOR gate 500, each gate
' having input terminals A and B and an output terminal Q.
~, The AND gates 301 and 302 will provide an on signal
at the output terminal Q only while both input terminals
A and B receive on signals. The OR gates 401 and 402 will
provide an on signal at the output terminal Q when either
or both input terminals A and ~ receive an on signal. The
NOR gate 500 will provide an on signal at the output
terminal Q only while both input terminals A and B receive
an off signal.
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Also shown in the diagram of FIG. 4 are three
flip-flop units 601r 602 and 603 each including input terminals
A and B and a pair of output terminals marked 0 and 1. The
marking 0 stands for an off condition and the marking 1 stands
for an on condition in that state of the flip-flop unit when
the input terminal A has been subjected to an on pulse. When
an input terminal B of any of the flip-flop units is subjected
to an on pulse, the condition of the pair of output terminals
will each changeto the reverse of that indicated at FIG. 4
and will remain so reversed until the input terminal A is
again subjected to an on pulse.
The flip-flop unit 601 i5 turned into the condition
illustrated in FIG. 4 by a pulse in line 901 from the one shot --
unit 201 upon receipt of a bight signal in the line 172' which
begins at top dead center of the sewing machine needle
reciprocation. As a result, line 902 is placed in an on
condition readying AND gate 301 to produce an output signal
should a pattern selection pulse be received via lines 139, 903
and 904. The flip-flop unit 602 would then be turned into the
condition illustrated in FIG. 4 and line 905 for actuating the
skip stitch mechanism would receive an on signal.
Also as a result of the flip-flop unit 601 being
tur~ed into the condition illustrated in FIG. 4, line 906 would
be placed in an off condition readying the one shot unit 202 ~ :
for response to a feed signal when received in the line 172
from the pulse generator 143. A pulse through line 907
from the one shot unit 202 to the flip-flop unit 603 will
place line 908 in an off condition thus readying the one shot
unit 203 for response to a signal from NOR gate 500 when the -
signal disappears from both the bight and feed lines 172' and
172 from the pulse generator 143 at 270 past top dead center
of the sewing machine needle reciprocation. A count pulse
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will then be generated in the line 909 for extracting stitch
pattern data for the succeeding stitch.
In addition to pulsing the one shot unit 203,
operation of the NOR gate via line 910 causes the flip-flop
unit 602 to change into a condition opposite that illustrated
in FIG. 4 terminating operation of the skip stitch actuating
mechanism. In this manner the needle reciprocation will be
interrupted for only one stitch when it is initiated by a pulse
in the pattern selector line 139.
The count pulse in line 909 via line 911 causes both
OR gates 401 and 402 to signal the flip-flop units 601 and
603 to change into the condition opposite that illustrated
in FIG. 4. From the time at 270 before top dead center until
top dead center, AND gate 301 will be disabled and a pattern
pulse received in the line 139 will not actuate the skip stitch
mechanism.
Another portion of the logic circuit shown in FIG.
4 which will now be described assures that the count pulse in
line 909 will be inhibited whenever the skip stitch mechanism
is actuated by a pulse from the flip-flop unit 602 in line 905.
Such inhibition of the count pulse assures that stitch pattern
data corresponding to the first stitch of a newly selected
pattern will be retained at the memory output until the sewing
machine needle reciprocation mechanism is again rendered
operative and is ready to reflect such pattern information
in the resulting stitched seam.
The flip-flop unit 603 will be turned immediately
into the condition opposite that illustrated in FIG. 4 by a
pattern selection pulse in the line 139 applied to the OR
gate 402 producing an on signal in the line 912 leading to ~
the flip-flop unit 603. This will prevent the one shot unit ~`
203 from delivering a count pulse at the output terminal Q
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thereof. In addition, an on signal in line 905 actuating the
skip stitch mechanism will be applied Via line 913 to the input
terminal A of the AND gate 302. This together with an on
signal in line 903 resulting from a pattern selection applied
to the input terminal s of the AND gate 302 will cause an on
signal to be delivered at the AND gate 302 output terminal Q
via the line 914 to the OR gate 401 so that an on signal will
be delivered via the line 915 to the terminal B of the flip-
flop unit 601. A resulting on signal in the line 906 will
prevent the one shot unit 202 from applying a signal in
: the line 907 to the flip-flop unit 603. The one shot unit
203 will thus be inhibited from producing a count pulse until
the next stitch forming cycle has occurred in which the skip
stitch mechanism is not actuated by an on signal in the line
905.
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