Sewing Machine

With the recent wide spread of zigzag sewing machines and with the advance in mechanism as well as in its function, it has become desirous that the sewing machine could be intermittently driven to make intermittent stitches, besides the conventional function of the sewing machine to produce the ordinary continuous stitches.

The present invention has been devised to realize a sewing machine which can produce intermittent stitches without any adverse influence to the conventional functions of the sewing machine.

The primary object of the invention is to provide a sewing machine with a stopping device for stopping the main shaft of the sewing machine in a predetermined position, so that the needle of the sewing machine may be stopped in a predetermined position at each revolution of the main shaft.

Another object of the injection is to provide a selecting device for selecting an ordinary continuous stitching operation of high or low speed and an intermittent stitching operation of sewing machine. means

A still further object of the invention is to provide a foot controller and an electric control circuit for operating the machine stopping device of the invention, which is pressed down to stop the main shaft of the sewing machine after one revolution thereof and is released to allow the main shaft to make the next revolution.

Many other features and characteristics of the present invention will be apparent from the following description of the embodiment of the invention by reference to the attached drawings, in which,

FIG. 1 is a perspective view of the sewing machine and machine controller of the present invention.

FIG. 2 is a partly sectioned rear view of the sewing machine showing a device for stopping the main shaft of the sewing machine in a predetermined position which is set to operate the sewing machine to produce the normal stretch stitching.

FIG. 3 shows the machine stopping device of the invention partly in a vertical cross section.

FIGS. 4 to 8 show the machine stopping device in various operating positions.

FIGS. 9 to 11 show another embodiment of the machine stopping device of the invention in various operating positions.

FIG. 12 shows a selecting device in vertical cross section for selecting the ordinary continuous stitching at high or low speed and intermittent stitching.

FIG. 13 is a vertical cross section along line Y-- Y of FIG. 12.

FIG. 14 is another embodiment of the selecting device of the invention, and

FIG. 15 is an electrical circuit of the invention.

The invention will be explained with reference to the attached drawings. In FIGS. 1 to 8, which show the first embodiment of the invention, a sewing machine (1) is provided with a controller (2) having a pedal (2'). Upper shaft (3) is journalled in the machine frame and is rotated in the counterclockwise direction, as viewed in FIG. 2, by a motor (4) via a rotary shaft (4') of the motor (4), motor pulley (5), first belt (6), intermediate pulley (7), second belt (8) and a pulley (9) of the upper shaft (3). The needle is vertically reciprocated in the well known manner by rotation of the upper shaft (3). The pulley (9) is connected to the upper main shaft (3) by means of an intermediate bushing (12) fixedly connected to the upper main shaft and a clutch device which will be decribed hereinafter. Flywheel (13) is fixedly mounted on the end of the upper shaft (3) as shown in FIG. 3. Rubber ring (15) or a ring of frictinal material of the thread winding device (14) is adapted to be pressed against the flange face (16) of the pulley (9) to thereby be rotated to wind a thread on a bobbin (not shown) mounted on the shaft of the thread winding device (14). Number (18) denotes a clutch operable to allow the rotation of the pulley (9) relative to the upper shaft (3) when the thread winding device (14) is shifted to the operative position to wind a thread on the bobbin, and the clutch is composed of a roller (17) and a clutch lever (19) which prevents the roller from shifting from its fixed position.

Stop cam member (20) is fixed on the inner side of bushing (12) by means of screws (21) (22) to rotate with the upper shaft (3), and is formed with a cam portion (23) and a cam portion (24) and arranged substantially diametrically opposite cam portion 23.

A holder (25) is turnably mounted on at its one end on a screw (26) fixed to the machine frame, is pulled at its other end (27) by a spring (28) in the clockwise direction, and is held in a stopped position by means of a nut (29) mounted on the free end part and inserted in a square hole (31) of stop (30) which is fixed to the machine frame as shown in FIG. 3. Number (32) denotes a pawl which is at its intermediate portion turnably mounted in the holder (25) by means of screw (34) and the nut (29), and is pulled at the upper end (35) thereof by spring (36) in the counterclockwise direction around the screw (34). A face 33 in the region of the upper end of the pawl (32) engages the cam portion (24) of stop cam member (20) when the holder (25) is rotated in the clockwise direction. A lower portion (37) of the pawl (32) contacts the holder (25), and thus the pawl is held in a stopped position. Actuating member (38) is turnably mounted on an axis (39) fixed to the lower part of the pawl (32). The actuating member (38) is formed with a contacting portion (40) as shown and the contacting portion is adapted to engage the cam portion (23) of the stop cam member (20). A pin (41) is provided on the actuating member (38). When the pin (41) is pushed upwards, the member (38) is turned in the clockwise direction around the axis (39) and as the result, the contacting portion (40) is moved to engage the cam portion (23). When the machine is set to the ordinary continuous stitching, the actuating member (38) is biased in the counterclockwise direction by a spring (43) provided between the member (38) and lever (42), and the contacting portion (40) is kept away from the cam portion (23) of the stop cam member (20). Lever (42) of the shape as shown is at its intermediate portion turnably mounted on an axis pin (44) provided on the intermediate portion of the holder (25), and is biased in the clockwise direction by torsion spring (45). When the machine is set to the ordinary continuous stitching, the flat portion (46) at one end of the lever (42) slightly engages the pin (41) of the actuating member (38) or is kept away therefrom. Further this lever (42) is divided in two parts and these parts are adjustably connected by a screw (47) threaded into holes (48) at both end portions of the parts. The upper end portion (51) of lever (50) presses against the other end portion (49) of the lever (42) against the torsion spring (45) as shown in FIG. 2. As the lever (50) is pulled upwards by a spring (52) provided between the lever (50) and the pivot pin (44) of the lever (42), the lever is kept in a predetermined position. The lower portion of the lever (50) projects into a plug receptacle box (53) (FIG. 13). A vertical slot (54) is provided in the lower portion of the lever (50) and within this slot (54) a manually operated portion (56) of a selector switch (55) is inserted. Thus when the portion (56) is depressed until the undersite thereof engages the lower edge of the slot (54) in the lever (50) and depresses the lever (50), the lever (50) is downwardly shifted against the spring force of (52). This downward movement of the lever (50) actuates the machine stopping device as will be explained later on in detail.

With reference to FIGS. 9 to 11, which show a second embodiment of the machine stop device, stopper cam member (20') and cam portions (23') and (24') are the same as those in the first embodiment. However, the difference is that the holder (25) is eliminated in that embodiment. Instead, the pawl (32') is turnably mounted on the sewing machine (1) by means of screw (34') and its upper portion (35') is pulled by a spring (36') to turn in the counterclockwise direction, and is maintained at a stopped position by a pin (58) fixed to the machine frame. The pawl (32') is adapted to engage the cam portion at its upper engaging face (33'). The actuating member (38') on which a pin (41') is mounted, is turnably mounted on the lower part of the pawl (32'). The contacting portion (40') of the actuating member (38') is adapted to engage the cam portion (23') of stop cam member (20') during the clockwise turning movement of the lever (42') which is turnably mounted on the machine frame by screw (59'), in the same manner as in the first embodiment. In this connection the actuating member (38') is biassed by a spring (43') in the counterclockwise direction. The lever (42') is pressed by a spring (45') to turn in the clockwise direction, and its turning movement is limited by a pin (60) fixed to the machine frame. The spring (45') contacts, at its one end, a pin (61) secured to the sewing machine (1), and contacts at its other end, one arm of the lever (42').

The selecting device for selecting the ordinary continuous stitching and the intermittent stitching will be explained, referring to FIGS. 12 and 13.

The selecting switch (55) and manually operating portion (56) are provided for this purpose. The operating portion may be moved stepwise to three positions such as "High," "Low" and "Intermittent" as shown in FIG. 3. When the operating portion (56) is set to "High" position, A.C. voltage of 0 to 100V is supplied to the motor (4) through the controller (2) from A.C. source as shown in FIG. 15. When the operating portion (56) is set to "Low" position, D.C. half wave voltage of 0 to about 70V is supplied to the motor through the controller (2) and diode (D). When the operating portion (56) is set to "Intermittent" position, the lever (50) is moved down together with the operating portion (56) and the needle stopping device is actuated, and concurrently D.C. half wave voltage of 0 to about 60V is transmitted to the motor through the controller (2), diode (D) and resistor (R.sub.0) connected in series to the circuit for the motor (this circuit formation may be made common to the circuit in case of "Low" stitching). Number (62) (FIG. 13) denotes an element to retain the lever (50) in a lower position. The element is pivoted on the lower part of the lever by means of a pin (63) and is formed with a projection (64) and spring (65) at its upper portion and further with a cam (66) at its lower portion to engage the operating portion (56). The projection (64) prevents the lever (50) from being pulled up by tension of the spring (52) when the lever (50) has been lowered. When the element (62) goes down together with the lever (50), the spring (65) of the element (62) is pressed against a shoulder (68) of dividing wall (67) within the plug receptacle box (53) and the element (62) is rotated in the counterclockwise direction and then the projection (64) engages a step (69) in the plug receptacle box. When the operating portion (56) is at the upper part of the slot (54), the cam (66) of the element (62) is pressed against the operating portion as shown in FIG. 2. When the operating portion (56) is moved to the lower part of the slot (54), the cam (66) of the element (62) enters the passage for the operating portion (56) within the slot (54) as shown in FIG. 13. On the other hand, when the operating portion (56) is moved up, the cam (66) of element (62) is engaged by the operating portion (56) and the element is turned in the clockwise direction, so that the projection (64) is released from the step (69) and the lever (50) is pulled upwards by the spring (52). When the operating portion (56) is moved to the steps of "High" and "Low" the lever (50) can be operated with a comparatively weak pressing force. But when the operating portion (56) is moved down to the lower position exceeding "Low" position, the operating portion (56) has to overcome the resistance of spring (52) as well as spring (65), and therefore, much greater pressing force is required (actually around 200g). The operating portion (56) is in a shape as shown in FIG. 12. A contact (71) is suitably pressed against terminals (72), (73), (74) and (75) as is vertically movable together with the operating portion (56). When the contact (71) engages terminals (72), (73), the machine is set to a high speed ordinary continuous stitching and when the contact (71) engages terminals (73), (74), machine is set to a low speed ordinary continuous stitching and when the contact engages terminals (74), (75), the machine is set to an intermittent stitching.

If the low speed ordinary continuous stitching function is not required, the lever (50') can be made oscillatory around an intermediate pivot thereof, as shown is FIG. 14 and the vertical movement of the operating portion (56) is made to impart oscillatory movement to the lever (50') in such a manner that the portion (56) engages or releases the lower end (66') of the lever (50') during the vertical movement thereof. Thus the upper end (51') of lever (50') can press against the lever (42") against the action of spring (45') or releases the lever (42"). Such a structure may, of course, be applicable to the three kind of stitching operations of the present invention.

FIG. 15 is an electric circuit according to the invention in which (A) denotes a plug to be fitted to the power source. (C.sub.1) denotes a controlling element for the machine controller having variable resistor (R) and slider (P). (B.sub.1) is connector of the machine controller (F) is an electric control circuit furnished in the sewing machine and (B.sub.2) is a connector of the control circuit. (E) is an illumination lamp, (M) is a motor. (C.sub.2) is the controlling element in the sewing machine and numeral (56) denotes a manually operating portion and numerals (72), (73), (74) and (75) denote switch contacts, which are all corresponding to those as shown in FIG. 12. (D) is a diode, (R.sub.0) is a resistor.

The operation of the proposed device will now be discussed.

The ordinary continuous stitching will be explained with reference to FIG. 2. Namely when the operating portion (56) of the switch (55) is set to "High" or "Low", the lever (50) is pulled upwards by the spring (52) to rotate the lever (42) in the counterclockwise direction against the spring (45) so that the lever (42) will not act on the actuating member (38). In this instance, the lever (42) causes the actuating member (38) to turn in the counterclockwise direction by means of spring (43). The contacting portion (40) of the actuating member (38) is, therefore, kept out of the passage of cam portion (23) of stop cam member (20) so that the stop cam member can be freely rotated by the main shaft (3) of the sewing machine. In this connection, the pawl (32) is not rotated in the clockwise direction by the actuating member (38) and is held in the inoperative position by the spring (36). The holder (25) is pulled by the spring (28) in the clockwise direction and the upper part of the nut (29) contacts the upper edge of the square hole (31). Thus the upper shaft (3) freely and continuously rotates to produce the stretch stitches at an optional speed by pressing the machine controller (2).

Now, the intermittent stitching is discussed. When the operating position (56) of the switch (55) is set to "Intermittent" D.C. half wave voltage of 0 to about 60V is supplied to the motor (4) and accordingly the sewing machine is not rotated at high speed but rotated at low speed even if the controller (2) is pressed down to the maximum degree. In the meantime, when the operating portion (56) is moved downwardly and set as shown in FIG. 13, the lever (50) goes down, and the spring (65) of the element (62) touches the shoulder (68) of the dividing wall (67) within the plug receptacle box (53) and the element (62) is rotated in the counterclockwise direction and the upper part of the projection (64) engages the step (69) of the box (53), and the lever (50) is prevented from rising and held in the lower position. Then, the lever (42) is rotated in the clockwise direction by pressure of the spring (45) until it is stopped by the holder (25), and the flat portion (46) at one end of the lever (42) pushes up the pin (41) to rotate the actuating member (38) in the clockwise direction against tension of the spring (43) so that the contact portion (40) of the member (38) is shifted into the path of the cam portion (23) of the stop cam member (20). The clockwise turning movement of the lever (42) is stopped as the corner of the flat end portion (46) of the lever (42) contacts the opposing face of the holder (25).

FIG. 5 shows a condition in which the cam portion (23) rotates in the counterclockwise direction together with the upper shaft (3) and engages the contact portion (40) to rotate the actuating member (38) in the clockwise direction until the pin (41) leaves from the flat end port (46) of the lever (42) and is pressed against the pawl (32). Since the cam portion (23) further rotates to turn the contact portion (40) farther in the clockwise direction and pushes it out of the path of the cam portion (23), and the contacting portion (40) engages the outer periphery of cam (23) as shown in FIG. 6, the pawl (32) is turned around the pivot screw (34) on the holder (25) in the clockwise direction against the tension of spring (36) together with the actuating member (38). As the result the upper corner (33) of the pawl is shifted into the path of the cam portion (24) and is engaged by the cam (24), but the cam is not instantly stopped by the pawl (32), because the corner (33) is pushed by the rotating cam portion (24) and the holder (25) is rotated in the counterclockwise direction around the pivot axis (26) against the tension of the spring (28) until the nut (29) on the free end (27) of the holder (25) is pressed against the lower edge of the square hole (31) of the fixed stop (30) as shown in FIG. 7. Thus the main shaft (3) of the sewing machine is stopped in this position. In this instance the actuating member (38) is shifted to a position spaced from the cam portion (23) and turned in the counterclockwise direction by spring (43), until pin (41) on the actuating member (38) engages the flat portion (33) at the end of lever (42).

The above operation of the constituent part has been effected when the pedal (2') of the machine controller (2) is pressed down to supply the electric current to the motor.

When releasing the controller pedal (2'), no rotational force is important to the main shaft (3) of the sewing machine and consequently the spring (28) pulls upwards the left end portion of the holder (25) to rotate the same in the clockwise direction until the nut (29) engages the upper edge of the square hole (31) of the stopper (30). Consequently the pawl (32) rotates the cam (24) with its upper corner (33) for a little distance in the clockwise direction. At the same time the spring (36) turns the pawl (32) in the counterclockwise direction about the pivot axis (34) and shifts the upper corner (33) of the pawl (32) out of engagement cam with portion (24), and then the actuating member (38) returns back to the first operative position where the contacting portion (40) is located in the path of the cam portion (23) as shown in FIG. 4. According to the invention, the main shaft (3) of the sewing machine stops completely at a position to which the main shaft is turned counterclockwise together with the stop cam member (20) as shown in FIG. 8. If the stop position of the main shaft (3) is predetermined to correspond the upper dead point of the needle at which the needle is stopped, it would be possible to stop the needle at the upper dead point thereof at each cycle of rotation of the main shaft. Then the controller pedal (2') is pressed down again, the above mentioned operation of associated parts is repeated and the upper shaft (3) is stopped at the same position is repeated and the upper shaft 3 is stopped at the same position after one rotation thereof. By repeating this operation, the intermittent stitching can be carried out as the main shaft of the sewing machine is stopped at a predetermined position to stop the needle at the upper dead point thereof per rotation of the main shaft.

With reference to FIGS. 9-11, the second embodiment of the instant needle stopping device will be explained. When the operating portion (56) of the switch (55) is set to "Intermittent" position, the lever (50) is moved down and as the result, the lever (42') is turned in the clockwise direction by the action of torsion spring (45') until the lever (47') is stopped by a pin (60') fixed to the machine frame. Consequently the lever (42') pushes the pin (41') on the actuating member (38') with the flat portion (46') to shaft the contact portion (40') of the actuating member (38) into the path of the cam portion (23') as shown in FIG. 11. Since the cam portion (23') makes one revolution from the position as shown in FIG. 9, and pushes the contact portion (40') out of the path of the cam portion (23') after one revolution thereof, the actuating member (38') is turned in the clockwise direction until the pin (41') is pressed against the pawl (32'). Then this pawl (32') is turned in the clockwise direction against the force of the spring (36') together with the member (38'). Consequently the upper engaging corner (33') of the pawl (32') is brought into the path of the cam portion (24'). and engages the cam portion (24') of the stop cam member (20') to stop the main shaft (3') of the sewing machine. However, at the instance, since the contact portion (40') of the actuating member (38') is still pushed by the cam portion (23') in the clockwise direction, the pawl (32') is still being turned in the clockwise direction. Namely the corner (33') partly engages the cam portion (24') as shown in FIG. 9. The cam portion (24') rotates a little farther while the contact portion (40') of the actuating member (38') is spaced from the cam portion (23'), but due to the mutual action between the cam portion (24') and the corner (33') the cam portion (24') and the upper engaging corner (33') of the pawl (32') completely engage each other as shown in FIG. 10. In this state, the pawl (32') will not be disengaged from the cam portion (24') by the action of spring (36') as long as the main shaft (3') of the sewing machine is supplied with driving power. Namely, so long as the controller pedal (2') is pressed down, the sewing machine is kept stopped in the condition as shown in FIG. 10. When the controller pedal is released, no rotational force is applied to the main shaft (3') and accordingly to the stop cam member (20), and as result, pawl (32') is pulled by the spring (36') and brought out of the engagement with the cam portion (24'). Thus the sewing machine stops. In the instant case, the contact portion (40) of the actuating member (38') is again brought into the path of the cam portion (23'). When the control pedal (2') is pressed down again, the same operation of associated parts is repeated to stop the sewing machine at a fixed position. Therefore, by repeating the operation of the controller (2'), stepwise rotation of the main shaft for the intermittent stitching as in the first embodiment is produced.