US3071090A - Stop motion mechanism for sewing machines - Google Patents

Description

Jan. 1, 1963 F. F. VZEIER 3,071,090

STOP MOTION MECHANISM FOR SEWING MACHINES Filed March 17, 1961 6 Sheets-Shet 1 N E g 5 g INVENTOR. Frederick E Zeier WITNESS BY TTORNE Y Jan. 1, 1963 F. F. ZEIER STOP MOTION MECHANISM FOR SEWING MACHINES Filed March 17, 1961 6 Sheets-Sheet 2 E lzg m I25 86 9 86 55 82 IN VENT 0R, Frederick E Zeier Fig.2

WITNESS AT ORNEY Jan. 1, 1963 F. F. ZElER 3,071,090

STOP MOTION MECHANISM FOR SEWING MACHINES Filed March 17, 1961 6 Sheets-Sheet 3 INV EN TOR.

Frederick E Zeier WITNESS ,4 [Luv ATTORNEY Jan. 1, 1963 F. F. ZEXER STOP MOTION MECHANISM FOR SEWING MACHINES Filed March 1'7, 1961 6 Sheets-Sheet 4 :2" 33 III Fig.6

INVENTOR. Frederick F. Zeier TOBNE Y WITNESS Jan. 1, 1963 F. F. ZEIER 3,071,090

STOP MOTION MECHANISM FOR SEWING MACHINES Filed March 17, 1961 6 Sheets-Sheet 5 I N VEN TOR.

Frederick E Zeier c7 WITNESS TTURNEY Jan. 1, 1963 F. F. ZEIER 3,071,090 STOP MOTION MECHANISM FOR SEWING MACHINES Filed March 17, 1961 6 Sheets-Sheet 6 IN VEN TOR.

Frederick E Zeier WITNESS TORNEY United States Patent Ofifice i atented Jan. 1, 1963 3,071,090 STOP MOTION MEQHANESM FGR SEWEN'G MACHINES Frederick F. Zeier, Morristnwn, N.J., assignor to The Singer Manufacturing @cmpany, Elizabeth, N.J., a corporation of New Jersey Filed Mar. 17, 1961, er. No. 96,578 4 Claims. (Cl. 112-219) The invention relates to cyclically operated sewing machines, and more particularly, to a stop motion mechanism for driving and stopping a cyclically operated sewing machine in a predetermined position of the parts thereof.

In the operation of a cyclic sewing machine such as a buttonhole sewing machine, a button sewer, a tacking machine, or the like, one of the most serious problems involves stopping of the machine after a predetermined number of stitches have geen formed. Stitch forming instrumentalities, thread handling mechanisms, and work feeding devices have been developed in the art to the point where they are no longer per se the limiting factors in the speed of operation of cyclic sewing machines. The factor in cyclic sewing machines which limits the speed of operation and thus the overall efiiciency of the machine is the means usually referred to as a stop motion mechanism which in stopping the machine serves to dissipate the kinetic energy of all the moving parts therein.

The manner in which the stop motion mechanism absorbs this kinetic energy reflects not only on the longevity, dependability, quietness, and smoothness of operation of the stop motion mechinism itself but also of each train of mechanism in the sewing machine which branches from the stop motion mechanism.

It is an object of this invention to provide a novel and improved stop motion mechanism in which at the end of each cycle of sewing machine operation, the sewing machine is gradually brought to a predetermined stopped position such that the forces stemming from the kinetic energy of the moving parts of the sewing machine are minimized and higher sewing speed during the cycle may be accommodated.

It is also an object of this invention to provide a novel planetary gearing system in a stop motion mechanism with means for rearranging the planetary gearing at the end of each sewing cycle to provide for a reduction in the speed of operation of the sewing machine prior to movement into a predetermined stopped position.

With the above and additional objects and advantages in view as will hereinafter appear, this invention comprises the devices, corn binations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a prefered embodiment in which:

FIG. 1 represents a side elevational view of a sewing machine having the stop motion mechanism of this invention applied thereto,

FIG. 2 represents an enlarged rear elevational view of the sewing machine of FIG. 1 with portions of the machine frame broken away,

FIG. 3 is an enlarged horizontal cross sectional view of a portion of the sewing machine taken substantially along line 33 of FIG. 2,

FIG. 4 is a cross sectional view of the brake actuating mechanism taken substantially along line 4-4 of FIG. 3,

FIG. 5 is an enlarged vertical cross sectional view taken substantially along line 5-5 of FIG. 1, and illustrating the connections for starting the sewing machine,

FIG. 6 is a cross sectional view taken substantially along line 6-6 of FIG. 5,

FIG. 7' is an enlarged vertical cross sectional view taken substantially along line 77 of FIG. 2 and illustrating the planetary gearing drive for the sewing machine as well as the brake and predetermined positioning mechanism,

FIG. 8 is a reduced cross sectional view taken substantially along line 8-8 of FIG. 7,

FIG. 9 is a cross sectional view taken substantialiy along line 9-9 or FIG. 7 and illustrating the planetary gearing, and

FIG. 10 represents a perspective view of a portion of the stop motion mechanism of FIG. 6 with portions of certain of the parts broken away to illustrate the relationship of parts of the planetary gearing system.

Referring particularly to FIGS. 1, 2 and 3 of the drawings 11 denotes the bed of a sewing machine casing from which extends a bracket arm 12 overhanging the bed. The sewing machine illustrated in the drawings is of a type adapted to sew a straight buttonhole, however, the stop motion mechanism of this invention is adapted for use with practically any type of cyclic sewing machine. Since the particular sewing machine disclosed in the drawings forms no direct part of this invention, only portions of the sewing machine mechanism are disclosed and described herein, it being understood that any other known cyclic sewing mechanism of this type may be used.

The drive for the sewing mechanism in the sewing machine is derived from a main shaft 13 (see FIG. 3) journaled in the bed 11. By the use of mechanism (not shown) the main shaft serves to impart translatory motion to a work clamp of which the hinged upper jaw is indicated at 14 in FIG. 1. The main shaft serves to impart oscillatory motion to a needle bar driving rock shaft 15 carrying a rock arm 16 having operative connections for imparting endwise work penetrating movement to a needle bar 17 which carries a pair of needles 18. The main shaft 13 also drives mechanism (not shown) for jogging the needle bar laterally in varying amplitudes including a particularly wide amplitude at each end of the work clamp travel to provide for barring stitches at each end of the buttonhole.

A shaft 19 carried in the bed is preferably associated with the mechanism for jogging the needle bar in the barring stitches at each end of the but-tonhole such that the shaft 19 partakes of one half revolution during the barring operation at each end of the buttonhole. The shaft 19 provides a control connection between the sewing mechanism and the stop motion mechanism.

Also included as a part of the sewing machine mecl1- anism is a knife 20 operatively connected to a rock shaft 21 in the bracket arm. By mechanism (not shown) which has counterpart in the prior art, the knife actuating rock shaft 21 is operatively connected to mechanism driven by the main shaft as, for instance, the needle bar driving rock shaft 15 during the last needle oar stroke of each sewing cycle. Carried at the rear end of the knife actuating rock shaft is a collar 22 formed with a radial lug 23 which also serves as a control connection between the mechanism of the sewing machine and the stop motion mechanism.

Fulcrumed at 39 in the bracket arm is a sewing machine starting lever 31 to which is secured one end of a link chain 32 which meshes with a sprocket 33 fast on a shaft 34 journaled in the bracket arm. The other end of the link chain is connected to a return spring 35 anchored in the machine bed. The shaft 34 carries a cam 36 tracked by a roller follower 37 carried by a lever 38 in the bracket arm. The lever 38 serves, as it is urged by the cam 36, first to lower the upper jaw '14 of the work clamp and then to separate the driving connection between the needle bar driving rock shaft 15 and the knife driving rock shaft 14-. Any of a plurality of latch means may be'employed. to constrain the lever 38 in cam influenced position and to release the lever 38 in stages at the completion of each sewing cycle. One such latch is illustrated by the latch lever 39 in FIG. 3 which is biased by a spring 40 to underlie and constrain the lever 33 in cam influenced position and is associated with tripping mechanism (not shown) influenced by the sewing mechanism to release the lever 33 sufficiently to establish a driving connection between the needle and knife driving rock shafts on the last needle bar stroke of each cycle of sewing machine operation. The starting lever 31 also formed with a camming blade 41 which serves to shift the stop motion mechanism into running position as will be described hereinbelow.

The stop motion mechanism of this invention includes a means for rendering effective and ineffective a driving connection between a belt from an electric motor or the like (not shown) and the main drive shaft 13, coupled with a means for locking the main shaft in a predetermined position of rotation. The arrangement which will be described in detail hereinbelow is such that upon depression of the starting lever 31 the driving connection between a drive belt and the main drive shaft will be established and the locking means for the shaft will be rendered ineffective and the parts of the stop motion mechanism constrained in this running position by the radial lug 23 on the knife driving rock shaft 21 until actuation of the knife at the completion of the sewing machine cycle. This stop motion mechanism also includes a means controlled by the shaft 19 which is operated during the barring operations in each cycle of sewing machine operation for reducing the speed of operation of the main drive shaft 13 prior to the Positive stopping of the main drive shaft by the locking means.

With particular reference of FIG. 7, the sewing machine main shaft 13 is formed with an end portion 50 or reduced diameter on which is fitted a sleeve member 51 secured for rotation with the main shaft by a pair of keys 52. The free extremity of the sleeve member is formed with a spirally inclined ramp 53 having at the outermost part a notch 54 by which the main shaft is locked in predetermined stopped position.

Extending radilly from the sleeve member 51 is a flange 55 in which is fixed at equal angular spaces three shouldered studs 56. Journaled on a bushing 57 on each of the shouldered studs is a planet gear 58. The planet gears 53 are arranged each in mesh with a sun gear 59 secured for rotation with a hub portion 60 extending to one side of a disk 61 formed with a V belt pulley half 62. The opposite side of the disk 61 is formed with an extended cylindrical hub portion 63 the hub portions 60, 63 being journaled on a bushing 64 on the sleeve member 51.

The planet gears 58 are also in mesh with an internal gear 65 formed on a drum 66 which is supported not only by the gears 58 but also by a shouldered ring 67 of synthetic plastic bearing material, such as nylon or the like, which is held by screws 68 to radial cars 69 formed on the flange 55 of the sleeve member 51 and engages a shoulder 76 formed internally of the drum 66.

Rotatable and axially slidable on a bushing sleeve 71 on the cylindrical hub portion 63 is a disk 72 formed with a V belt pulley half 73 opposite the pulley half 62. Secured to the disk 72 by screws 74 is an annular clamp member 75 by which a thrust bearing 76 is sustained on the disk 72,. A flanged ring 77 fits against the thrust bearing 76 and provides an annular seat against which bears a pair of pins 73 slidable axially in diametrically opposite bores in a main shaft bushing member 79. A force applied axially to the pins 78 toward the free extremity of the main shaft 13 will thus act through the thrust bearing 76 to urge the pulley half 73 toward the pulley half 62 thus urging a belt entrained thereon drivingly against the pulley half 62 to drive the sun gear 59.

Slidable axially of the main shaft on the shouldered studs 56 for movement into and out of meshing engagement with the internal gear 65 on the drum 66 is a locking gear 80. Three coil springs 81 seated in retainer cups 32 set into the flange 55 bear against the locking gear at equal angular spaces about the gear and serve to bias the locking gear into mesh with the internal gear 65. The locking gear is also provided with a plurality of lugs 83 disposed parallel to the main shaft 13 and extending over the periphery of the flange 55 between the radial ears 69 thereon. Each of the lugs 83 is apertured as at 64 and accommodates an arm 85 of one of a plurality of hell crank levers 66 one for each of the lugs 83. The bell crank levers 86 are fulcrurned on pins 87 in the flange 55 and are each formed with an actuating arm 88 disposed abutting a ring 89 axially slidable on the sleeve member 51.

As best illustrated in FIG. 2 a U-shaped bracket is fixed to the machine bed by means of fastening screws 1% and a spacing block 102 formed with spaced upstanding arms 103 and 104 disposed one at each side of the axis of the main drive shaft 13. A fulcrum pin 165 (FIG. 8) is set into the bracket arm 103 and is embraced on opposite sides by the semi-circular journals 106 of a pair of identical brake shoes 107 which are constrained on the fulcrum pin 165 by springs 108 biasing the brake shoes together. Secured as by rivets 109 to the brake shoes are arcuate segmental brake linings 110 disposed within the drum 66. Iournaled in the bracket arm 104 is a shaft 111 carrying at one side of the bracket arm a lever arm 112 and formed at the opposite side of the bracket arm with a blade 113 shaped reetangularly in cross section and, as illustrated in FIG. 7, disposed between the brake shoes 107 such that upon turning of the lever arm 112 the blade 113 will cam the brake shoes apart in opposition to the springs 108 and urge the linings into frictional braking engagement with the interior of the drum 66.

The operations of rendering the brake effective and of disengaging the locking gear 80 from the internal gear 65 are coordinated to occur substantially simultaneously by means of a brake actuating member 126 which is fast on a rock shaft 121 journaled in an extension 12' of the bracket arm 12. The brake actuating member is formed with bifurcated extremities 122 and 123 straddling the axis of the main shaft 13 as illustrated in FIG. 2 each extremity being formed with a lobe 124- disposed to abut the slidable ring 8 9 by which the bell crank levers 86 are operated to disengage the locking gear 80 from the internal gear 65. The bifurcated extremity 122 is also formed with an extension 125 in which is threaded a screw 126 formed with a conical tip 127 adapted to contact and cam the brake actuating lever arm 112 to render the brake effective. A lock nut 128 on the screw 126 provides for adjustment of the screw 126 to insure simultaneous effectiveness of the brake and the means for disengaging the locking gear.

The positive stopping of the main shaft 13 in a predetermined position of rotation is accomplished by a swinging frame 130 carried on a pivot pin 131 secured in the bracket arm extension 12'. A stud shaft 132 is journaled in the swinging frame 136 in substantial axial alignment and beyond the free extremity of the main shaft 13 and the hub 133 of a rock lever 134 is secured to the stud shaft 132. A locking lug 135 which projects from the hub 133 of the rock lever is adapted to abut the spirally inclined ramp 53 of the sleeve member 51 fast on the main shaft 13 and to seat in the notch 54 in the sleeve member to lock the main shaft in predetermined position of rotation.

The rock lever 134 is pivoted as at 136 to a plunger rod 137 which is guided in a swivel block 133 journaled in the swinging frame 130 and provided with recoil springs 139 and 140 constrained, respectively, between the rock lever 13d and the swivel block, and between the swivel block and a retaining washer 141 secured at the upper free extremity of the plunger rod by lock nuts 142.

Referring to FIGS. 1, 2 and 5, the swinging frame 130 is shift-ed to carry the locking lug 135 out of the notch 34 to release the main shaft when the machine is started by means of a link 150 pivoted to a boss 151 formed on the swinging frame 130 and to one arm 152 of a bell crank lever clamped to a rock shaft 153 journaled in the machine bed 11. The other arm 154 of the bell crank is flattened and disposed in the path of the cam- Ining blade 41 on the starting lever 31. A coil spring 155 operatively conneced to the link 150 and to the machine bed biases the swinging frame 130 toward the position of engagement of the locking lug 135 with the notch 54.

The swinging frame 13% is maintained in running position with the locking lug 135 out of the notch 54 by means of an upstanding latch lug 156 formed on the swinging frame 130 which is illustrated in FIG. 1 underrides a notched finger 157 formed on a latch lever 158 fulcrumed on the bracket arm 12 and lightly biased downwardly by a spring 159. As illustrated in FIGS. 1 and 2, the latch lever 153 is formed with a lip 160 which overlies the radial lug 23 carried by the collar 22 on the knife driving rock shaft 21. Actuation of the knife driving rock shaft 21 will thus release the swinging frame 130. An emergency stop lever 161 fulcrumed as at 162 on the machine casing is operatively connected to a plunger 1'63 slidable vertically in a boss 164 carried on the bracket arm 12. An abutment 165 which may be in the form of a nut threaded on the plunger underlies the latch lever 158 and upon depression of the emergency stop lever 161 will disengage the latch finger 157 from the latch lug 156 to release the swinging frame 130. The plunger 163 also carries a projection 166 at the lower extremity which underlies an arm 167 formed on the brake actuating member 120 such that when the emergency stop is used the brake Will be rendered effective to aid in stopping the sewing machine.

The arm 152 of the bell crank lever 152, 154 which transmits motion from the starting lever 31 to the swinging frame 130 carries a roller 170 thereon disposed in engagement with a rock arm 171 clamped on a rock shaft 172 journaled across the bed 11. A rock frame 173 formed with spaced upstanding rock arms 174 disposed one on each side of the main drive shaft is secured to the rock shaft 172 with the rock arms 174- disposed each in engagement with one of the pins 73 by which the belt pulley halves are shifted toward one another. Depression of the starting lever 31 thus simultaneously shifts the swinging frame ran into running position and effects a driving connection of a V belt on the pulley halves 62, 73 with the main drive shaft.

The brake actuating member 120 is operated to retard the speed of operation of the main drive shaft 13 prior to stopping by a mechanism which senses the turning of the shaft 19 of the sewing machine during the barring operations in the sewing of a buttonhole and renders effective the brake actuating member 12 during the final barring operation. The shaft 19 carries a spiral shaped cam 180 as illustrated in FIG. 2 with a radial surface 181 joining the peripheral portions of largest and smallest diameter. Biased against the periphery of the earn 181 by a coil spring 182 anchored on the machine bed is a follower pin 183 carried by a follower lever arm 184 journaled on a pivot pin 185 secured in the machine frame. Carried on the pivot pin and secured to the follower lever arm for turning movement therewith is a slabbed block 186 on which is pivoted as at 187 a latch lever 188 formed with a latch finger 18? and with a latch release tab 1% disposed in the path of a plunger 191 slidable in a bracket 192 fastened to the bracket arm extension 12 by the fastening screw 193'. A spring 194 arranged between the bracket 192 and an enlarged head 195 on the plunger biases the plunger out of engagement with the latch release tab 1%, however, the head 195 of the plunger is disposed in the path of an abutment screw t5 1% threaded in the swinging frame 130. Freely journaled on the pivot pin 185 adjacent to the slabbed block 186 is the hub 197 of a lever arm 198 which underlies a rock arm 199 fast on the rock shaft 121.

The lever arm 1% is disposed above an end wall 26% of the machine bed 11 which limits the downward movement of the lever arm under the influence of gravity such that a latch notch 201 formed in the hub 197 of the latch lever is maintained in the path of motion of the latch finger 189 on the latch lever 18% in response to movement of the follower lever arm 18 under the influence of the cam 18-51 on the shaft 19. During the first barring operation on a buttonhole the earn 180 in moving a half revolution will turn the latch finger 189 into a position overlying the latch notch 26 1 and under the influence of a light compression spring 202 the latch finger will be seated in the notch. During the second barring operation at the conclusion of a cycle of sewing machine operation, the cam 1811 in moving the second half revolution will bring the radial portion 181 of the cam 180 past the cam follower pin 186 and the spring 182 will become effective to turn the follower lever arm 184, and the lever arm 198 which is latched thereto resulting in a turning movement to the brake actuating member 12%) into effective position. The spring 182 will continue to hold the brake actuating member 12 in effective position until the locking lug drops into the notch 5- in the sleeve member 51 to stop the main shaft in a predetermined position. Movement of the swinging frame 136 occasioned by the locking lug 35 dropping into the notch 54, will shift the abutment screw 1% on the swinging frame and thereby the plunger 191 against the latch release tab 191) on the latch lever 138 to turn the latch finger 189 out of the latch notch 261 thereby releasing the brake actuating member 120.

When the sewing machine is stopped between sewing cycles, the parts of the stop motion mechanism occupy the position illustrated in FIG. 7 in which the pulley halves 62 and 73 are shifted apart rendering a driving belt thereon ineffective, and the locking lug 135 on the swinging frame 134) is seated in the notch 54 holding the main shaft in a predetermined angular position. The locking gear 89 will be urged by the springs 81 into meshing engagement with the ring gear 65. Since the planet gears 58 are also in mesh with the ring gear 65, the planetary gear system is locked for turning movement as a unit.

Upon depression of the start lever 31, the camming blade 41 in turning the bell crank lever 153, 154 effects driving engagement of a drive belt with the pulley half 62 by way of the roller 17-0, the rock arm 171, rock arms 174 fast therewith, pins 78, ring 77, thrust bearing 76, and the axially slidable pulley half 73. Simultaneously by way of the link 1511, the swinging frame 13% will be turned to withdraw the stopping lug 135 out of the notch 54 freeing the main shaft for rotation at the speed of rotation of the belt pulley 62, '73. Engagement of the latch lug 156 on the swinging frame with the latch finger 157 will maintain the stop motion parts in the running position during the normal cycle of operation of the sewing machine.

During operation of the sewing machine while the first barring stitches are being made at one end of a buttonhole, the shaft 19 will be turned one half revolution from the position illustrated in FIG. 2. In this movement, the cam will shift the rock arm 184 and the latch lever 188 carried on the block 1% fast on the rock arm 184 so as to bring the latch finger 18% into registry with the notch 231 in the hub of the lever arm 1%. The drive of the sewing machine main shaft, however, continues at a high speed in one-to-one speed ratio with the belt pulley 62, 73.

Near the completion of the bu-ttonhole sewing operation, the last few stitches comprise the final barring operation during which the shaft 19 is turned half a revolu- 7 tion into the position illustrated'in PIG. 2. During this turning movement of the shaft 19, the radial portion 181 of the cam 180 is preferably timed to traverse the follower pin 133 of the rock arm 184 while several barring stitches remain to be made. The rock arm 184 will thus be released and in response to the spring 182, the lever arm 192 latched to the rock arm 184 by the latch lever 188 will engage and shift upwardly the rock arm 199 fast on the rock shaft P1 carrying the brake actuating member 120. Referring to FIG. 7 this movement of the member 12 3 will effect by way of the lobes 124 and axial shift of the slidable ring 89 and turning the levers 86 to withdraw the locking gear 3;; from meshing relation with the ring gear 65. Simultaneously, the movement of the member 120 will carry the conical tip of the screw 126 against the lever arm 112, causing the blade 113 fast therewith to urge the brake linings 1116 against the interior of the drum 66. The gears 59, 58 and 65 will, therefore, be free to operate as a planetary gear system. The ring gear 65 under the influence of the brake linings fit) will serve as a stationary reaction element and the sun gear 59 turning at the same rate of speed as the belt pulley 62, '73 will transmit motion to the sleeve member 51 and the main drive shaft 13 at a reduced rate by way of the planetary gears 58. The specific speed reduction then effected will depend upon the specific design of the planetary gear system. It has been found that a speed reduction on the order of one third of the speed of the belt pulley 62, '73 provides highly advantageous results.

During the period of effectiveness of the planetary gear system f, 58, 65, the speed of the main shaft 13 will be gradually reduced. The energy represented by the inertia of the moving parts of the sewing machine will be transmitted through the planetary gearing and the belt pulley 62, 73 to the drive belt and to the preferably constant speed drive means such as an electric motor associated therewith.

At the completion of the sewing machine cycle of operation, therefore, the main shaft will have been slowed by the planetary gear system to a fraction of the normal operating speed and a large percentage of the inertia of the moving sewing machine parts will have been absorbed by the sewing machine drive. The actuation of the buttonhole cutting knife 24 during the last stitch in the cycle, serves by way of the radial arm 23 fast on the knife actuating rock shaft 21 to release the latch lever 15% which maintains the swinging frame 130 in running position.

Release of the swinging frame 130 and movement thereof in response to the spring 155 carries the locking lug 135 against the spiral ramp 53 of the sleeve member such that the lug 135 will drop into the notch 54 when the main shaft 13 has turned into a predetermined angular position. By way of the link 159, this motion of the swinging frame 130 will release the bell crank lever 152, 154 and with it the rock frame 173 and the rock arms 174 thereof which will free the pulley half 73 to shift axially and carry the drive belt out of driving engagement with the pulley half 62.

When the locking lug 135 drops into the notch 54 the kinetic energy remaining in the main drive shaft 13 and the moving parts of the sewing machine connected therewith will be absorbed by the coil spring 139 on the plunger 137. Recoil will be controlled by the spring ltd-t to overcome any overthrow in the stopping of the machine. Furthermore, the movement of the locking lug 135 into the notch 54 will also permit an increment of movement of the swinging frame 134} to carry the abutment screw 1% and the plunger 191 influenced thereby against the tab 1% of the latch lever 1%? to release the brake actuating member 129. The brake linings lltl will thus be shifted out of braking relation with the drum 66 and the locking gear 80 will be released for movement in response to the springs 81 into meshing relation with the ring gear 65. This movement of the locking gear into mesh with the ring gear occurs smoothly during the final angular movement of the locking gear as the main shaft is stopped or during the slight recoil movement thereof.

The stop motion mechanism of this invention in providing for a gradual speed and inertia reduction of the moving parts of the sewing machine correspondingly effects reduction in the maximum forces which must be withstood in the stopping of a sewing machine. As a result, the top speed of sewing machine operation may be increased appreciably and the time required for each cycle of sewing machine operation may be reduced Without an increase of impact loading on the sewing and stop motion mechanisms.

In addition the reduction of the impact loading during stopping reduces the wear and maintenance not only of the stop motion mechanism but also of the various trains of sewing mechanism connected to the sewing machine main shaft.

Having set forth the nature of this invention, what I claim herein is:

1. A stop motion mechanism for a sewing machine having a casing, a main shaft journaled in said casing, and a substantially constant speed motor for driving said main shaft, said stop motion mechanism comprising, a sun gear journaled freely on said main shaft and adapted to be driven by said motor, a plurality of planet gears disposed in mesh with said sun gear, a planet gear carrying member secured for rotation with said main shaft, a reaction gear disposed in mesh with said planet gear, means for securing said reaction gear relatively to said planet gear carrying member, means for positively locking said main shaft relatively to said casing in a definite position of rotation, operator influenced starting means for rendering ineffective said positive locking means and simultaneously establishing driving relation between said motor and said sun gear to drive said main shaft at the substantially constant speed of said sun gear, stop means controlled by the operation of said sewing machine for simultaneously rendering effective said positive locking means and for interrupting driving relation between said motor and said sun gear, and intermediate low speed drive means rendered effective by the operation of said sewing machine prior to the operation of said stop means for releasing said reaction gear from said planet gear carrying member and simultaneously applying frictional resistance to turning of said reaction gear to establish a drive for said main shaft at a fraction of the speed of said sun gear.

2. A stop motion mechanism as set forth in claim 1 including means rendered effective by the operation of said stop means for rendering ineffective said intermediate low speed drive means and resecuring said reaction gear relatively to said planet gear carrying member.

3. A stop motion mechanism for a sewing machine having a rotary main shaft, comprising a sun gear journaled freely on said main shaft, means for establishing and interrupting a drive for said sun gear at a substantially constant speed, a plurality of similar planet gears disposed in mesh with said sun gear, a planet gear carrying member secured for rotation with said main shaft, a plurality of stud shafts secured on said planet gear carrying member substantially parallel to the axis of rotation of said main shaft, means for journalling said planet gears one on each of said stud shafts, a reaction gear disposed in mesh with said planet gears, a locking gear slidable axially of said main shaft on said plurality of stud shafts, means for shifting said locking gear relatively to said planet gear carrying member into meshing relation with said reaction gear to establish a drive for said main shaft at the substantially constant speed of said sun gear, means for applying a frictional resistance to turning movement of said reaction gear, and means effective simultaneously with said frictional resistance applying means for shifting said locking gear relatively to said planet gear carrying member out of meshing relation with said reaction gear to establish a drive for said main shaft at a fraction of the speed of said sun gear means for positively locking said main shaft in a definite position of rotation, manually operable means for releasing said positive locking mums for said main shaft and simultaneously operating said means for establishing said drive for said sun gear, stop means operated by said sewing machine for rendering said positive locking means for said main shaft effective and simultaneously interrupting said drive for said sun gear, rendering ineffective said means for applying frictional resistance to turning movement of said reaction gear, and operating said means for shifting said locking gear relatively to said planet gear carrying member into meshing relation with said reaction gear, and means operated by said sewing machine prior to operation of said stop means for operating said frictional resistance applying means and simultaneously operating said means for shifting said locking gear out of meshing relation with said reaction gear to establish said drive for said main shaft at a fraction of the speed of said sun gear.

4 A stop motion mechanism for a sewing machine having a rotary main shaft, and means for positively locking said main shaft relatively to said sewing machine in a definite position of rotation comprising a sun gear journaled freely on said main shaft, means for establishing and interrupting a drive for said sun gear at a substantially constant speed, a plurality of similar planet gears disposed in mesh with said sun gear, a planet gear carrying member secured for rotation with said main shaft, a plurality of stud shafts secured on said planet gear carrying member substantially parallel to the axis of rotation of said main shaft, means for journalling said planet gears one on each of said stud shafts, a reaction gear disposed in mesh with said planet gears, a locking gear slidable axially of said main shaft on said plurality of stud shafts, spring means for shifting said locking gear relatively to said planet gear carrying member to bias said locking gear into meshing relation with said reaction gear to establish a drive for said main shaft at the substantially constant speed of said sun gear, a plurality of locking gear shifting levers, fulcrum means for each of said levers supporting said levers substantially radially on said planet gear carrying member, a thrust collar axially shiftable relatively to said main shaft and arranged in operative engagement with said plurality of levers, means operatively connecting said levers with said locking gear to shift said locking gear out of meshing relation with said reaction gear upon axial movement of said thrust collar in one direction, means rendered effective by the operation of said sewing machine for applying frictional resistance to turning movement of said reaction gear and simultaneously shifting said thrust collar in said one direction to establish a drive for said main shaft at a fraction of the speed of said sun gear and means operated by the sewing machine subsequent to the operation of said means for establishing said fractional speed drive for said main shaft for substantially simultaneously rendering said positive locking means for said main shaft effective, for rendering said interrupting means for said sun gear effective, and for rendering said fractional speed drive means ineffective.

References Cited in the file of this patent UNITED STATES PATENTS 1,138,309 Mace Mar. 2, 1915 2,659,249 Carr Nov. 17, 1953 2,863,411 Peets Dec. 9, 1958 2,870,655 Rockwell Jan. 27, 1959 2,906,222 Ketterer et al Sept. 29, 1959 2,966,810 Hayes Jan. 3, 1961

Claims (1)

1. A STOP MOTION MECHANISM FOR A SEWING MACHINE HAVING A CASING, A MAIN SHAFT JOURNALED IN SAID CASING, AND A SUBSTANTIALLY CONSTANT SPEED MOTOR FOR DRIVING SAID MAIN SHAFT, SAID STOP MOTION MECHANISM COMPRISING, A SUN GEAR JOURNALED FREELY ON SAID MAIN SHAFT AND ADAPTED TO BE DRIVEN BY SAID MOTOR, A PLURALITY OF PLANET GEARS DISPOSED IN MESH WITH SAID SUN GEAR, A PLANET GEAR CARRYING MEMBER SECURED FOR ROTATION WITH SAID MAIN SHAFT, A REACTION GEAR DISPOSED IN MESH WITH SAID PLANET GEAR, MEANS FOR SECURING SAID REACTION GEAR RELATIVELY TO SAID PLANET GEAR CARRYING MEMBER, MEANS FOR POSITIVELY LOCKING SAID MAIN SHAFT RELATIVELY TO SAID CASING IN A DEFINITE POSITION OF ROTATION, OPERATOR INFLUENCED STARTING MEANS FOR RENDERING INEFFECTIVE SAID POSITIVE LOCKING MEANS AND SIMULTANEOUSLY ESTABLISHING DRIVING RELATION BETWEEN SAID MOTOR AND SAID SUN GEAR TO DRIVE SAID MAIN SHAFT AT THE SUBSTANTIALLY CONSTANT SPEED OF SAID SUN GEAR, STOP MEANS CONTROLLED BY THE OPERATION OF SAID SEWING MACHINE FOR SIMULTANEOUSLY RENDERING EFFECTIVE SAID POSITIVE LOCKING MEANS AND FOR INTERRUPTING DRIVING RELATION BETWEEN SAID MOTOR AND SAID SUN GEAR, AND INTERMEDIATE LOW SPEED DRIVE MEANS RENDERED EFFECTIVE BY THE OPERATION OF SAID SEWING MACHINE PRIOR TO THE OPERATION OF SAID STOP MEANS FOR RELEASING SAID REACTION GEAR FROM SAID PLANET GEAR CARRYING MEMBER AND SIMULTANEOUSLY APPLYING FRICTIONAL RESISTANCE TO TURNING OF SAID REACTION GEAR TO ESTABLISH A DRIVE FOR SAID MAIN SHAFT AT A FRACTION OF THE SPEED OF SAID SUN GEAR.

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