US3832961A

US3832961A - Sewing machine drive control device

Info

Publication number: US3832961A
Application number: US00375476A
Authority: US
Inventors: S Nakamura; T Thukioka
Original assignee: Tokyo Juki Industrial Co Ltd
Current assignee: Juki Corp
Priority date: 1973-07-02
Filing date: 1973-07-02
Publication date: 1974-09-03
Anticipated expiration: 1991-09-03

Abstract

A sewing machine drive control device includes drive means, a prime mover shaft drivingly connected to the drive means to be driven thereby, a main shaft drivingly connected to the prime mover shaft to be driven thereby, a hollow cylindrical support member secured to the main shaft, an epicyclically movable unit receiving the prime mover shaft for rolling and sliding movement therein, a rotary member rotatably supported on the support member, a braking mechanism movable for contacting and separating from the rotary member, a clutch mechanism for drivingly connecting and disconnecting between the prime mover shaft and main shaft and control means for selectively controlling the braking mechanism and clutch mechanism so as to allow the epicyclically movable unit to only revolve and rotate and only rotate.

Description

United States Patent [191 Nakamura et al.

[ 1. Sept. 3, 1974 Fujita 112/220 Primary Examiner-*H. Hampton Hunter Attorney, Agent, or FirmWenderoth, Lind & Ponack ABSTRACT A sewing machine drive control device includes drive means, a prime mover shaft drivingly connected to the drive means to be driven thereby, a main shaft drivingly connected to the prime mover shaft to be driven thereby, a hollow cylindrical support member secured to the main shaft, an epicyclically movable unit receiving the prime mover shaft for rolling and sliding movement therein, a rotary member rotatably supported on the support member, a braking mechanism movable for contacting and separating from the rotary member, a clutch mechanism for drivingly connecting and disconnecting between the prime mover shaft and main shaft and control means for selectively controlling the braking mechanism and clutch mechanism so as to allow the epicyclically movableunit to only revolve and rotate and only rotate.'

3 Claims, 12 Drawing Figures PATENTED 31974 SNEEI u [If 6 SEWING MACHINE DRIVE CONTROL DEVICE BACKGROUND OF THE INVENTION This invention relates to a sewing machine drive control device and more particularly, to a sewing machine drive control device which is adapted to initially rotate the sewing machine at a low speed from the rest position of the machine and then increase the rotational speed or initially decelerate the sewing machine from the high speed rotation and then stop the machine.

There have been proposed a number of devices of the type referred to above and one of the conventional devices comprises two stationary pulleys and two loose pulleys having substantially the same diameter which are alternately disposed on the main shaft of a sewing machine. Two round belts which are driven at a higher speed and a lower speed, respectively, are trained over these pulleys and the mutual relationship between these pulleys and round belts is as follows:

That is, when the sewing machine is in its rest posi tion, the two round belts are over the loose pulleys. When the sewing machine is started, the belts are moved in the axial direction of the pulleys until the higher speed round belt is placed over the loose pulleys and the lower speed round belt is placed over the stationary pulleys whereupon the sewing machine is driven at a low speed. Thereafter, when the two round belts are further moved axially of the pulleys until the higher speed belt is placed over the stationary pulleys and the lower speed belt is placed over the loose pulleys whereupon the rotational movement of the sewing machine is accelerated.

When the sewing machine rotating at the high speed is to be stopped, both the two round belts are in succession moved in the opposite direction to that in which the belts are moved when the sewing machine is to be started whereby the rotating sewing machine is initially decelerated and then stopped.

Since the above-mentioned conventional sewing machine drive control device requires the round belts, slip frequently occurs between the belts and pulleys and in consequence, the driving force obtainable from the conventional sewing machine drive control device referred to above is small. Therefore, the conventional sewing machine drive control device has the following disadvantages: Firstly, the control device can not be suitably employed in a heavy duty sewing machine; secondarily, it takes a rather long time to increase the rotational speed of a particular sewing machine to a predetermined value and in consequence, the operational efficiency is low; thirdly, when a particular sewing machine is rotated at a high speed under the force of inertia, it takes a rather long time to decelerate the machine to a predetermined low speed and in conse quence, the operational efficiency is low; and lastly, before a particular sewing machine rotating at a high speed under the force of inertia is decelerated to a predetermined low speed, the machine is inadvertently stopped by the stop mechanism and in consequence, the parts of the machine are liable to a high impact.

SUMMARY OF THE INVENTION Therefore, one principal object of the present invention is to provide a sewing machine drive control device which can effectively eliminate the disadvantages inherent in the conventional like devices and which alleviates impact which may be given to the parts of a sewing machine in which the control device is incorporated when the machine is suddenly started and stopped whereby the machine parts are protected against the possibility of damage caused by the impact.

Another object of the present invention is to provide a sewing machine drive control device which can enable a sewing machine to go, in a short time, from its rest position to high speed rotation, and which can, in a short time, bring a sewing machine rotating at high speed to a stop, whereby the sewing efficiency of the sewing machine is improved.

A further object of the present invention is to provide a sewing machine dn've control device which has a driving force sufficient to positively drive even a heavy duty sewing machine. A still further object of the present invention is to provide a sewing machine drive control device which is compact and occupies a relatively small space within the body of a sewing machine.

The present invention will now be described referring to the accompanying drawings in which the invention is illustrated as being applied to a conventional cyclically operable sewing machine such as a bar tacking sewing machine in which the sewing operation is started by pulling a start lever and after a desired number of seam lines have been formed, the start lever automatically returns to the original position to stop the sewing machine. v

The above and other objects and attendant advantages of the present invention will be more readily apparent to those skilled in the art from a reading of the following description in conjunction with the accompanying drawings which show preferred embodiments of the invention for illustration purpose only, but not for limiting the scope of the same in any way.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show two different embodiments of a sewing machine drive control device constructed in accordance with the present invention.

FIGS. 1 through 6 inclusive show one preferred embodiment of sewing machine drive control device of the invention as being applied to a conventional cyclically operable sewing machine and these Figures show the relationship between parts of the control device when the sewing machine is driven at a high speed wherein;

FIG. 1 is a front elevational view in partial section of said preferred embodiment of sewing machine drive control device of the present invention as mounted on the rear portion of a sewing machine FIG. 2 is a side elevational view of said drive control device of FIG. 1 as seen on the right-hand side thereof;

FIG. 3 is a cross-sectional view taken substantially along the line III III of FIG. 2;

FIG. 4 is a cross-sectional view taken substantially along the line IV IV of FIG. 1;

FIG. 5 is a cross-sectional view taken substantially along the line V V of FIG. 1;

FIG. 6 is aacross-sectional view taken substantially along the line VI VI of FIG. 4;

FIGS. 7 and 8 are similar to FIGS. 2 and 1, respectively, but show the relationship between parts of the control device when the sewing machine is driven at a low speed;

FIGS. 9 and 10 are also similar to FIGS. 2 and 1, respectively, but show the relationship between parts of the control device when the sewing machine is in its rest position; and

FIGS. 11 and 12 are also similar to FIGS. 2 and 1, respectively, but show the relationship between parts of a modified embodiment of a sewing machine drive control device of the invention when the sewing machine on the rear portion of which the control device is mounted is driven at a high speed.

PREFERRED EMBODIMENTS OF THE INVENTION The present invention will now be described referring to the accompanying drawings and more particularly, to FIGS. 1' through 10 inclusive in which the first embodiment of sewing machine drive control device of the invention is shown as being mounted on the rear portion of a conventional cyclically operable sewing machine. A sewing machine main shaft 3 is rotatably supported in the rear portion of a sewing machine arm 1 by means of bearings 2 and extends rearwardly beyond the rear end of the arm I. The extension of the main shaft 3 supports a hollow cylindrical prime mover shaft 6 and a coaxial hollow cylindrical support member 13 thereon. The prime mover shaft 6 is rotatably supported on the main shaft 3 by means of needle bearings and the inner race 4 of a ball bearing is fitted on a portion of the outer peripheral surface of the prime mover shaft 6. The support member 13 is secured to the main shaft 3 by means of a knock pin 14 and the outer peripheral surface of the support member is formed with

stub shaft portions

7, 8 and 9, a flange l0 and a ball supporting portion 12 in which the ball 11 of the ball bearing is supported. The

stub shaft portions

7, 8 and 9, flange and ball support portion 12 have different diameters. A rotary member 20 is rotatably supported on the stub shaft portion 9 with needle bearings 16 interposed between the opposite surfaces of the rotary member and flange 10. The rotary member 20 carries the outer race of the ball bearing fitted therein against movement in the thrust direction and a cylindrical member 18 having a friction member 17 the outer surface of which tapers and is secured to the rotary member by means of set screws 19. Needle bearings 21 are disposed between the inner end of the prime mover shaft 6 and the adjacent end of the inner race 4 (the lefthand end as seen in FIG. 1) and the opposite face of the intermediate diameter stub shaft portion 9 and are normally urged in the right-hand direction by a compression coiled spring 22 (as seen in FIG. I). Since the force of the spring 22 urges the inner race 4 in the right-hand direction and the outer race is held against movement in the thrust direction the spring acts on the' ball 11 of the ball bearing so as to increase friction resistance on the inner race 4 and outer race 15. A hollow cylindrical clutch member 24 is fixedly secured to the right-hand or outer end of the ball supporting portion 12 of the support member 13 by means of a plurality of set screws 25. The clutch member 24 is shaped to cover the outer surface of the right-hand or outer end portion of the rotary member 20 and has a frusto-conical friction member 23 secured to the outer surface of the clutch member. A pulley 28 is provided on the prime mover shaft 6 with its complementarily shaped inner friction surface 27 in friction contact with the frusto-conical friction member 23 and keyed to the prime mover shaft 6 at 26 for axial movement relative to the shaft. A V-belt 30 is received and guided in the groove of the pulley 28 and drivingly connects the pulley to a high speed motor (not shown) so as to rotate the pulley at the speed of the motor. Thus, the pulley 28, prime mover shaft 6 and inner race 4 always rotate at the high speed imparted thereto by the motor and the pulley 28 is axially movable while the pulley is rotating.

A disc 33 is fixedly secured to the right-hand or outer end face of the pulley 28 by means of set screws 34 and has a spherical recess 32 in its lower portion adjacent the right-hand or outer end portion of the main shaft 3. A compression coiled spring 36 is received in an opening 35 formed in the main shaft outer end portion and normally urges the pulley 28 rightwards or outwardly through a ball 37 and the disc 33 as seen in FIG. 1.

A ring 38, a biasing member 39, a braking member 40, a biasing spring 41 and a ring 42 are freely received on the stub shaft portion 8 of the support member 13 in the mentioned order from the side of the stub shaft portion 8 adjacent the rotary member 20.

The braking member includes a friction surface 43 opposite the friction member 17, three radially extending holes 48 each having a beveled face or chamfered face 47 (see FIGS. 4 and 6) facing the biasing member 39 and a notch 49 in the periphery of the braking member. An engaging member 45 is provided so as to allow the braking member 40 to move axially, but to prevent the braking member from rotating and has the base secured to the braking member 40 by means of set screws 44 and the bifurcated free end adapted to freely receive a pin 46 extending from the arm 1 (FIG. 4).

The biasing member 39 includes a plurality of radially extending projections each of which faces to and is adapted to fit in the associated hole 48 in the braking member 40 and an arm 52 extending through and outwardly of the notch 49 in the braking member 40. The arm 52 is in the form of a triangle and formed with an elongated slot 51 therein. The biasing spring 41 is in the form of a leaf spring and has a plurality of radially extending biasing pieces 53 the free ends of which bias the braking member 40 rightwards (as seen in FIG. 1).

A stop member 54 has a conventional construction and includes an eccentric portion in the outer periphery, an engaging groove 55 and a detent 58 which is rockable about a pin 57 and urged to rotate in one direction by a spring 56 (FIG. 9).

The sewing machine arm 1 carries a conventional clutch lever 59 and an engaging lever 60 (FIGS. 1 and 2). The clutch lever 59 is pivotable about a pin 61 and has upper and

lower mounting portions

62 and 63. The clutch lever 59 has an upwardly extending resilient clutch plate secured to the right-hand end or outer end thereof by means of a set screw 71 and a horizontally extending actuation plate 72 secured to an intermediate point of the clutch lever by means of set screws 73. The clutch lever 70 is formed at the upper end with a

stepped portion

68 and 69 which urges a clutch ball 31 into the spherical recess 32 of the disc 33. The actuation plate 72 is connected to an operators treadle (not shown) and carries a pin 75 and an engaging member 78. A stop pin 65 is mounted in the

mounting portions

62 and 63 for upward and downward movement and has at the upper end a stop pawl 64 adapted to engage in the engaging groove 55 in the stop member 54.

A coiled spring 66 and a resilient member 67 mounted at the lower end of the stop pin 65 cooperate in absorbing shock which may develop as the stop pin 65 moves upwardly and downwardly. A stepped screw 74 is provided for transmitting the rotational movement of the clutch lever 59 to the biasing member 39. The stepped screw 74 is freely received in the slot 51 in the biasing member 39 and threaded into the clutch lever 59. A coiled spring 80 extends between and anchored to a pin 79 on the sewing machine arm 1 and a pin 75 on the actuation plate 72 so as to urge the clutch lever 59 about the pin 61 in the clockwise direction as seen in FIG. 2. The engaging member 78 mounted on the actuation plate 72 has different height portions 76 and 77 (FIG. 3). The former is higher than the latter.

The engaging lever 60 is pivotable about a pin 81 and supports at one end an engaging piece 86 and at the other end a friction engaging piece 83. The engaging piece 86 has a downwardly extending pawl 85 (FIG. 3) adapted to selectively engage one of the different

height engaging portions

76 and 77 of the engaging member 68. A coiled spring 82 is provided on the pin 81 and urges the engaging lever 60 about the pin 81 in the clockwise direction as seen in FIG. 1.

A cam 84 shown by the two dot-line in FIG. 1 is geared to the sewing machine main shaft 3 so that the cam is rotated at a rate lower than that at which the main shaft rotates and the peripheral surface of the cam is contacted by the friction contact piece 83. The peripheral surface of the cam 84 is formed with two different height raised

portions

87 and 88. The raised portion 88 is higher than the raised portion 87.

The operation of the sewing machine drive control device of the present invention will now be described.

In FIGS. 1 through 6 inclusive of the accompanying drawings, the relationship between the various parts of the device is shown when the main shaft 3 of the sewing machine is rotating at high speed. Thus, being driven from the motor.( not shown), the V-belt 30 rotates the prime mover shaft 6 and inner race 4 of the ball bearing at high speed. Since the friction surface 27 on the pullcy 28 and the friction member 23 of the clutch member 24 are in engagement with each other by the resiliency of the clutch plate 70, the main shaft 3 is rotated by the pulley 28 through the support member 13. At this time, the ball 11 will not rotate about its own axis because the inner and

outer races

4 and 15 thereof rotate, but revolves about the axis of the main shaft 3. The revolution of the ball 11 rotates the rotary member at the high speed whereby the main shaft 3 is rotated at the high speed from the rotating pulley 28 through the support member 13 as mentioned hereinabove. In this way, the cycle sewing machine is driven at high speed to form a desired seam line.

When the cam 84 rotates, the raised portion 87 on the cam pushes the friction contact piece 83 so as to cause the engaging lever60 to slightly pivot in the counter-clockwise direction against the action of the spring 82. The pivotal movement of the engaging lever 60 disengages the engaging pawl 85 on the engaging piece .86 from the higher engaging portion 76 on the engaging member 78 and the spring 80 biases the engaging member 78 to the position in which the lower engaging portion 77 is engaged by the engaging pawl 85. And the clutch lever 59 pivots slightly about the pin 61 in the clockwise direction whereby the various parts of the device are positioned in the position as shown in FIGS. 7 and 8 in which the sewing machine which is now rotating at the high speed is reduced its rotational speed to a predetermined value by the action as will be 5 described hereinbelow.

lO fore, the pulley 28 displaces in the right-hand direction as seen in FIG. 1 by the action of the spring 36 whereby the frictional contact between the friction surface 27 on the pulley 28 and the friction member 23 on the clutch member 24 is broken and in consequence, the

15 rotational movement will not be transmitted from the pulley 28 to the clutch member 24. As the clutch lever 59 pivots in the clockwise direction as mentioned hereinabove, the biasing member 39 also rotates slightly through the screw 74 and arm 52 and the projections 20 50 on the biasing member 39 enter the associated holes 48 in the braking member 40 as shown in FIG. 6 (2). Thus, the braking member 40 is displaced by the distance A as shown in FIG. 6 (l) by the action of the spring 41 and the friction surface 43 on the braking member 40 is forced to contact the friction member 17 on the rotary member 20 whereupon the rotary member 20 which is now rotating under the force of inertia is braked. This braking serves to impede the revolution of the ball 11 which is now rotating at the high speed under the force of inertia of the sewing machine and brakes the main shaft 3 to decelerate the main shaft rapidly. When the rotational speed of the braked rotary member 20 (or the outer race 15) becomes lower than that of the pulley 28 (or the inner race 4 which is transmitted the rotational movement of the pulley through the prime mover shaft 6), the ball 1] begins both its revolutional and rotational movement. Furthermore, when the rotary member 20 (or outer race 15) is stopped by the braking member 40, the rotational movement of the pulley 28 is transmitted to the main shaft 3 through the ball 11 which concurrently rotates and revolves in response to the rotation of the pulley (the rotational movement of the pulley is transmitted through the prime mover 6 and inner race 4 to the ball) and the support member 13. Therefore, the main shaft 3 is driven at the revolutional speed of the ball 11 which is substantially lower than the rotational speed of the pulley 28.

When the cam 84 rotates further until the higher raised portion 88 on the cam pushes the friction contact piece 83, the sewing machine which is now rotating at the reduced speed is stopped in a predetermined position on account of the following reason.

That is, when the friction contact piece 83 is pushed by the raised portion 88, the engaging lever is pivoted to disengage the engaging pawl from the engaging portion 77 whereby the clutch lever 59 is further pivoted in the same direction as described hereinabove and the various parts assume the position as shown in FIGS. 9 and 10.

As the clutch lever 59 pivots in the above direction, the biasing member 39 is further rotated thereby and in consequence, the projections 50 on the biasing member 39 which are now in the position as shown in FIG. 6 (2) come out of the associated holes 48 in the braking member 40 to assume the position as shown in FIG. 6 (l) in which the braking member 40 is moved leftwards by the biasing member 39. Thus, the frictional surface 43 of the braking member 40 is separated from the friction member of the rotary member 20 (FIG. whereby the rotary member is allowed to rotate freely and the rotational moment of the rotary member becomes substantially smaller than that of the main shaft 3. Therefore, the ball 11 merely rotates and will not transmit the rotational movement of the pulley 28 to the main shaft 3 and the rotary member 20 races at a reduced speed in the direction opposite to the rotational direction of the pulley 28.

And as the clutch lever 59 pivots in the manner mentioned above, the stop pawl 64 on the stop bar 65 contacts the outer peripheral surface of the stop member 54 which is now rotating at a low speed under the force of inertia and as the clutch lever 59 pivots further, the pawl 64 engages in the engaging groove 55 whereupon the main shaft 3 stops in a predetermined position.

The starting of the sewing machine is effected by pivoting the clutch lever 59 in the position as shown in FIG. 9 to the position of FIG. 2 through the manipulation of the treadle connected to the actuation plate 72 and when the sewing machine is started in the manner mentioned above, the various parts which are now in the position of FIGS. 9 and 10 assume the position as shown in FIGS. 1, 2, 3, 4, 5 and 6 (l) in which the main shaft 3 rotates at a high speed.

When the sewing machine is to be started, the manipulation is so effected that if the clutch lever 59 is maintained in the position as shown in FIG. 7 for a short time and then moved to the position of FIG. 2, the sewing machine can be first driven at a lower speed and then at a higher speed.

The advantages of the present invention are as follows:

l. The sewing machine which is rotating at a high speed can be stopped in a short time and the operational efficiency of the machine is improved. This is due to the fact that the main shaft which is rotating at a high speed under the force of inertia can be braked with a high force so the rotation of the braked main shaft is automatically reduced through the rotation of the pulley.

2. The impact which may be given to the parts of the sewing machine when the sewing machine is stopped can be reduced and in consequence, the machine parts can be effectively protected against possible damage. This is due to the fact that the rotational speed of the main shaft is always reduced immediately before the machine is stopped.

3. The torque which drives the main shaft is sufficient to positively drive heavy duty sewing machines. This is due to the fact that the rotational movement of the pulley can be transmitted through the V-belt to the main shaft at both high and low speeds.

4. Since the control device of the invention occupies a very small space within the sewing machine adjacent the main shaft, the entire sewing machine can be constructed compactly.

FIGS. 11 and 12 show a modified embodiment of the sewing machine drive control device of this invention in which an epicyclic train is employed in place of the ball 11 in the first embodiment. An inner gear 90 is fixedly secured to the rotary member 20 and corresponds to the outer race of the ball bearing in the first embodiment. The sun gear 91 is provided on the prime mover shaft 6 and corresponds to the inner race of the ball bearing in the first embodiment. A plurality of planetary gears 92 are rotatably supported on shafts 93 of the support member 13 and are in engagement with the inner gear and sun gear 91. These planetary gears 92 correspond to the ball 11 of the ball bearing in the first embodiment. The clutch member 24 is Furthermore, the clutch member 24 in either the first or second embodiment, respectively, can be eliminated by the provision of a member equivalent to the friction member 23 of the clutch member 24 on the rotary member 20. In such a case, when the friction surface 27 on the pulley 28 is caused to contact and separate from the above-mentioned equivalent member, the sewing machine drive can be controlled in the same manner as mentioned hereinabove. And the pivotal movement of the clutch lever 59 can be controlled through the manipulation of the operators treadle, an electromagnet, fluid pressure or any suitable mechanical means. It is to be understood that the sewing machine stop mechanism can be replaced by any suitable braking and stop mechanism.

Although only two embodiments of the invention have been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the arrangement of parts without departing from the spirit and scope of the invention as the same will now be under stood by those skilled in the art.

We claim:

1. A sewing machine drive control device comprising a main shaft rotatably journaled to a frame of said sewing machine, a prime mover shaft joumaled on said main shaft and movable therearound with respect thereto, a rotary member journaled about said main shaft and movable therearound with respect thereto, planetary members disposed about said main shaft and said prime mover shaft on supporting surfaces formed on said prime mover shaft, a carrier means secured to said main shaft for supporting said planetary members,

clutch means selectively operable for transmitting orimpeding the rotational movement from said prime mover shaft to said carrier means, and braking means supported on said frame in a non-rotative manner relative thereto for selective connection to said rotary member to allow said rotary member to selectively freely rotate or to stop.

2. A sewing machine drive control device as claimed in claim 1, further comprising single control means operatively connected to both said clutch means and said braking means for selectively controlling coupling said clutch means to said carrier means and for coupling said braking means to said rotary member.

3. A sewing machine drive control device comprising a main shaft rotatably joumaled to a frame of said sewing machine, a prime mover shaft joumaled to said prime mover shaft to said carrier means, said frictional clutch means being integrally rotatable with said prime mover shaft and axially movable with respect thereto during the rotation thereof, and frictional braking means supported on said frame in a non-rotative manner relative thereto for selective connection to said rotary member to allow said rotary member to selectively freely rotate or to stop.

Claims

1. A sewing machine drive control device comprising a main shaft rotatably journaled to a frame of said sewing machine, a prime mover shaft journaled on said main shaft and movable therearound with respect thereto, a rotary member journaled about said main shaft and movable therearound with respect thereto, planetary members disposed about said main shaft and said prime mover shaft on supporting surfaces formed on said prime mover shaft, a carrier means secured to said main shaft for supporting said planetary members, clutch means selectively operable for transmitting or impeding the rotational movement from said prime mover shaft to said carrier means, and braking means supported on said frame in a non-rotative manner relative thereto for selective connection to said rotary member to allow said rotary member to selectively freely rotate or to stop.

3. A sewing machine drive control device comprising a main shaft rotatably journaled to a frame of said sewing machine, a prime mover shaft journaled to said main shaft and movable therearound with respect thereto, a rotary member journaled on said main shaft and movable therearound with respect thereto, planetary members about said main shaft and said prime mover shaft on supporting surfaces formed on said prime mover shaft, a carrier means secured to said main shaft for supporting said planetary members, frictional clutch means selectively operable for transmitting or impeding the rotational movement from said prime mover shaft to said carrier means, said frictional clutch means being integrally rotatable with said prime mover shaft and axially movable with respect thereto during the rotation thereof, and frictional braking means supported on said frame in a non-rotative manner relative thereto for selective connection to said rotary member to allow said rotary member to selectively freely rotate or to stop.