US3237579A - Needle positioning mechanism for sewing machines - Google Patents

Description

March 1966 J. M. MEDYNSK] ETAL 3,237,579

NEEDLE POSITIONING MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet 1 Filed May 29, 1965 BY Jam /1- #104011 March 1966 J. M. MEDYNSK] ETAL 3,237,579

NEEDLE POSITIONING MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet 2 Filed May 29, 1963 Huh FIG.2

INVENTORS 6 1 A nsk'f March I, 1966 J. M. MEDYNSKI ETAL 3,237,579

NEEDLE POSITIONING MECHANISM FOR SEWING MACHINES Filed May 29, 1965,

3 Sheets-Sheet 5 FIG.5

INVENTORS TTORNEY United States Patent 3,237,579 NEEDLE POSITIONING MECHANISM FOR SEWING MACHINES Joseph M. Medynski, Ramsay, and John M. Medynski,

Oakland, N.J., assignors of fifteen percent to Victor M.

Helfand, New York, N.Y.,

Filed May 29, 1963, Ser. No. 284,210 8 Claims. (Cl. 112-219) The present invention relates to an improvement in sewing machines; especially to an improvement in sewing machines intended for industrial use, and more particularly 'to the provision of an improvement in such sewing machines whereby the needle bar of the machine will always be disposed in the same predetermined position, whenever the operation of the sewing head is stopped. This application is a continuation-in-part of our pending application, Serial No. 273,181, filed April 15, 1963.

In performing the sewing operation, especially in in-l dustrial sewing, a great deal of time is wasted by the operator of the machine when he stops the operation of the sewing head in order to remove and replace the work on the machine. To be able to remove the work and to replace it, the work must be free of the needle, and, to that end, the needle bar must be in its retracted or uppermost position. As, in the greater number of instances the needle bar will not end up in the required, work freeing position when the sewing machine head is halted, the operator is required, in most instances, to adjust the machine to raise the needle bar to the desired position by the slow, manual procedure of turning the fly-wheel of the sewing machine head until the needle bar is moved sufficiently to free the needle from the work. This relatively slow, manual adjustment consumes a great deal of the operators time and adds materially to the labor costs of the article on which he is working. Also, where the operator works on a piece basis, it can cut materially into his earning capacity.

It is the object of the present invention, therefore, to provide a sewing machine of the character described having a mechanism for automatically moving the needle bar to uppermost, work-freeing position, each time the operation of the sewing machine head is halted.

It is another object of the present invention to provide a needle bar adjusting mechanism for a sewing machine, of the character described, which is powered by the motor of the sewing machine proper, and is automatically electrically controlled by the same movement that halts the sewing machine head operation.

It is also an object of the present invention to provide a needle bar adjusting mechanism for a sewing machine, of the character described, which is of relatively simple and sturdy construction and may be readily installed on the machine; is simple and easy to operate and control; and is reliable in its operation.

The foregoing and other objects and advantages of the sewing machine of the present invention will become more readily apparent to those skilled in the art from the embodiment thereof more or less diagrammatically shown in the accompanying drawing and from the description following. It is to be understood, however, that such embodiment is shown by way of illustration only, to make the principles and practice of the invention more readily comprehensible, and without any intent of limiting the invention of the specific details therein shown.

In the drawings:

FIG. 1 is a front, elevational view of the material portion of a sewing machine embodying the present invention;

FIG. 2 is a fragmentary rear elevational view of the sewing machine of FIG. 1; with the sewing head omitted;

FIG. 3 is an exploded view of the sewing machine head 3,237,579 Patented Mar. 1, 1966 driving and needle bar positioning mechanism of the invention;

FIG. 3a is a fragmentary, sectional view diagrammatically illustrating one form of the overriding clutch means for use in the main drive of the sewing machine with the overdrive thereof.

FIG. 4 is a fragmentary view, on an enlarged scale, taken on line 4-4 of FIG. 1, showing a pedal-actuated switch in the electrical circuit of the needle bar positioning mechanism;

FIG. 5 is a schematic view of the electric circuit of the needle bar positioning mechanism of the invention.

Referring now in greater detail to the embodiment of the invention illustrated in the drawing, the same show a sewing machine of one conventional type frequently used in industry, which includes the sewing machine head, generally designated as 10, mounted on the work table, 12, and having the continuously running electric motor, 14, supported from the underside of the table as on brackets 15, and provided with the driving shaft 16, carrying a clutch member or disc 18, at its end.

The sewing head 10 includes the main shaft 20, carrying a driving pulley wheel 22, and the vertically reciproble needle bar 24, operatively connected to shaft 20 by the lever 26, and the reciprocating arm 28, connected to shaft 20, in the conventional manner.

Motor shaft 20 -is intermittently operatively connectible to the motor 14 by a clutch-driven system which includes the driven shaft 30, which is rotatably and axially slidably journalled, coaxially with shaft 16, in spaced bearings 32, at the end of bracket 34, dependently secured on the underside of table 12. Driven shaft 30 carries a pulley wheel 36, at one end, which is connected by belt 38 to the sewing head pulley wheel 22, and carries at its other end a clutch member or disc 18a, which may be moved to contact cooperating clutch member 18 on shaft 16 by axial displacement of shaft 30. Engagement and release of the clutch may be effected by means of a rocker arm 40, pivotally supported on extension 42 of bracket 34, whose one forked end 44, engages over a pin 46, set into shaft 30, between bearings 32, and whose other end is pivotally connected to one end of a rod 48, whose other end is pivotally secured on the rear or inner edge of a treadle, 49. The rocker arm 40, rod 48 and treadle 50 are so arranged that depressing the rodoonnected edge of the treadle will displace shaft 30 toward the motor and close the clutch, to operate the machine head 10, and the elevation of the rear end of the treadle will release the clutch, to stop operation of the sewing head 10.

It may be here stated that the foregoing is descriptive of only one conventional form of a clutch-drive sewing machine for which the needle bar positioning mechanism of the invention may be adapted. Such mechanism includes a secondary or overriding clutch-drive system for the relatively slower, limited rotation of the shafts 30 and 20, and is set into operation upon the release of the clutch of the main drive system to rotate the shaft 20 from whatever position in may have been at on the inactivation of the main drive system, to the position where the needle bar is in predetermined position, as in the uppermost position.

Such secondary or overdrive system includes a secondary driving shaft 50, journalled in spaced brackets 15, and is rotated, preferably at lower speed, from the motor drive shaft 16, as by the relatively large pulley wheel 52, carried on shaft 50, which is connected by belt 54, to the relatively smaller pulley wheel 56, carried on shaft 16. Shaft 50 also carries a clutch member or disc 58 at one end. The overdrive system also includes a driven shaft, 60, rotatably and axially slidably journalled, coaxially with shaft 5@ in spaced bearing 62, on the end of bracket 64, depending from table 12. The shaft 60 carries on its end facing shaft a cooperating clutch member or disc 58a, and at its other end a relatively small pulley wheel, 68, which is connected by belt 79, to a relatively larger pulley wheel 72, mounted on shaft 343 for idling when the latter is rotated by the motor shaft 16 and for engaging it for rotation with shaft 60 when the main drive clutch is released as by ratchet means or by an overriding clutch, more or less diagrammatically illustrated at 73, in FIG. 3, in a manner well known to persons skilled in the art and through necessary to be specifically illustrated. It may here be stated that instead of the toothed pulley wheels and toothed belts for connecting the shafts of the overdrive with the shafts of the main drive, especially for connecting shafts 60 with shaft 30, ratchet wheels and a ratchet chain may be used.

The overdrive shaft 60 may be axially displaced into and out of clutch engaging position by means similar to that used in the main drive; namely, by a rocker arm 74, pivoted on extension 76, of bracket 64. The rocker arm 74 may have a forked end which engages over the pin 78, set into shaft at; between bearings 62 in which it is slidably journaled. The other end of the rocker arm 74 may be tilted to slide shaft an axially toward and away from shaft 50. To effect such tilting, the other end of rocker arm 74 is connected to a rod 80, which is connected to or continuous with the armature of a solenoid 82. The solenoid 82 is connected in an electric circuit in such manner that when the circuit is closed and the solenoid is activated, rod 80 will be moved to tilt the rocker arm 74 in a direction for sliding shaft 60 into clutch engaging position, and, conversely, when the circuit is broken through solenoid 82, rod 80 will move to tilt rocker arm 74 in a direction to displace shaft 60 into clutch releasing position.

The electric circuit of the overdrive system may include a normally open switch which is operated to close the circuit through solenoid 82, either automatically, by the movement of the machine mechanism to disconnect the transmission from the motor 14 to the sewing head shaft 22, as by the movement of the mechanism releasing the clutch of the main drive, as treadle 49; or by a separate, substitute or alternate mechanism that may be actuated by the operator at the same time, or immediately before or after operation of the treadle. The circuit through the solenoid 82 also includes a switch associated with the sewing head shaft 22 which is closed at all times, except when the shaft 22 is rotated to the position where it holds the needle bar 24 in the desired, predetermined position, as in the uppermost position; at which point such switch is automatically opened to break the solenoid circuit and thus release the overdrive clutch 58 and stop the operation of the sewing head at the instant that the needle bar is in predetermined position. The latter switch may, preferably, be in the form of a rotary switch, designated as 84, of a type well known in the art and not thought necessary to be shown in detail, which may be mounted over the end of shaft of the sewing head.

For treadle actuation, the normally open switch of the solenoid circuit may be a mercury type switch 86, having the tilting arm or control pin 88. The switch 86 is preferably mounted in a frame 90, secured to the end of rocker arm 40, with the pin 88 tilted by gravity into switch opening position. The treadle rod 48 passes through the bottom of frame 90 and is provided, in the portion thereof disposed within the frame, with a shoulder 92, arranged to engage and tilt pin 88 into switch closing position when rod 48 is moved upwardly to clutch releasing position. A collar 94, is mounted on rod 48, immediately below frame 90, arranged to engage the frame to move it upwardly with rod 48 to complete the movement of tilting rocker arm 40 to release clutch 18.

It may here be stated and it will be readily understood that where the clutch of the main drive shaft is controlled by the knee acting on a knee plate, in the manner well known in the art, switch 86 or a similar switch may be arranged to be actuated by the movement of such knee plate, in a manner that will be readily understood by and be clear to those skilled in the art and not thought necessary to be specifically illustrated.

It will be clear that while the main drive or transmission is connected to the motor and the sewing is in operation, the secondary transmission or overdrive will remain idle and stationary, for the reason that its clutch 58-58a is open. This is made possible by the fact that pulley wheel 72, which is connected to driven shaft 60 of the overdrive, is free wheeling or idling. When switch 86 is closed as by movement of treadle 49 to release clutch 18-18% overdrive clutch is engaged and its driven shaft 60 is rotated. Since shaft 60 rotates at lesser speed than shaft 30, pulley wheel '72 will still idle. When upward movement of rod 48 is completed, clutch 1848a is released and shaft 30 disconnected from motor 14. It will then be driven by shaft 60, through pulley wheels 63 and 72, the latter no longer idling, to rotate at a relatively low speed. Shaft 30 will, in turn, rotate sewing head shaft 20. If switch 86 is closed at the instant when shaft 20 is holding the needle bar 24 in predetermined position, rotary switch 84 will then be open, the circuit through solenoid 84 will remain open, and the overdrive, whose action is not then needed, will remain inactive. However, if, when switch 86 is closed when shaft 20 is at any other position, switch 84 will be in closed position and the circuit; through the solenoid will be completed, thus activating solenoid 82 and tilting rocker arm 74 to close clutch 58-58a, activating the secondary drive to rotate shaft 20, as described above, to the point where it will move the needle bar 24 to predetermined position, at which point switch 84 will be automatically opened to break the circuit through the solenoid 82 and de-activate it and release clutch 58-58a. It will be understood, of course, that the maximum period of operation of the overdrive will be minimum.

This completes the description of the improved sewing machine of the present invention. It will be readily apparent that improvement of the present invention provides easy to control, reliable, automatic means for positioning the needle bar of a sewing machine in any predetermined position each time the sewing machine is stopped. It will also be apparent that, because the mechanism is operated directly from the sewing machine motor, it is of relatively simple, safe and economical construction and convenient to control.

It will also be further apparent that the numerous modifications and variations may be made in the sewing machine of the present invention, by anyone skilled in the art, in accordance with the principles of the invention, hereinabove set forth and without the exercise of any inventive ingenuity. We desire, therefore, the protection of the patent laws for any and all such modifications and variations that may be made within the spirit of the invention and the scope of the claims hereto appended.

What we claim is:

1. In a sewing machine, including a sewing head having a rotary drive shaft, a needle bar operatively connected to said rotary shaft for reciprocation thereby, a motor, a main transmission including a main driven shaft operatively connected to said rotary shaft and movable means releasably operatively connecting said main driven shaft to said motor, the improvement consisting of a sec ondary transmission rotatable by said motor at a lesser speed than said main transmission, said secondary transmission including a secondary driven shaft parallel to said main driven shaft, means interconnecting said driven shafts for rotation simultaneously in one direction, means releasably operatively connecting said secondary driven shaft with said motor, and means operable by said movable means upon movement thereof to release said main driven shaft from said motor to connect said secondary driven shaft with said motor, and means controlled by said rotary drive shaft for releasing said secodary driven shaft from said motor upon positioning of said needle bar at a predetermined position.

.2. The sewing machine of claim 1, wherein said means interconnecting said driven shafts includes a wheel secured to said secondary driven shaft and a wheel mounted on said main driven shaft, said last named wheel arranged to freely rotate on said main driven shaft in one direction and to engage said last named driven shaft when rotated in the opposite direction, and means operatively interconnecting said wheels.

3. The sewing machine of claim 2, when said first named wheel is of lesser diameter than said last named wheel.

4. The sewing machine of claim 2, wherein said secondary transmission includes a shaft supported for rotation in fixed position and means operatively connecting said shaft to said motor, said secondary driven shaft releasably operatively connected to said shaft.

5. The sewing machine of claim 1, wherein said means operatively releasably connecting said secondary shaft to said motor is electrically controlled and includes a solenoid connected in an electric circuit, a normally open switch in said electric circuit, means closing said switch upon actuation of said movable means for releasing said main driven shaft from said motor, a normally closed switch in said circuit, and automatic means actuated by said rotary shaft opening said normally closed switch when said rotary shaft is disposed in position holding said needle bar in predetermined position, and means operatively connecting said solenoid to said secondary driven shaft for connecting the same to and releasing it from said motor.

6. The sewing machine of claim 5, wherein said normally closed switch is a. rotary switch actuated by said rotary shaft.

7. The sewing machine of claim 5, wherein said secondary driven shaft is slidably supported, and a pivoted arm is connected to said shaft and to said solenoid for movement by said solenoid to move said shaft into and out of connection with said motor.

8. The sewing machine of claim 5, wherein said normally open switch is actuated by said movable means releasably operatively connecting said main driven shaft with said motor upon movement of said means into shaft releasing position.

References Cited by the Examiner UNITED STATES PATENTS 2,517,567 8/1950 Hill et al 112-219 2,708,415 5/ 1955 White 112219 2,836,276 5/ 1958 Schwab et a1 112--219 3,026,834 3/ 1962 Prentzel 112-219 3,114,340 12/ 1963 Hedegaard 112219 FOREIGN PATENTS 1,274,781 9/ 1961 France.

820,995 11/ 1951 Germany.

OTHER REFERENCES Schwab: German application, 1,134,266, printed August 2, 1962 (Kl 52a 56/04) (2 s'hts. dwg., 2 pp. spec).

FRANK J. COHEN, Primary Examiner.

ROBERT V. SLOAN, JORDAN FRANKLIN,

Examiners.

Claims (1)

1. IN A SEWING MACHINE, INCLUDING A SEWING HEAD HAVING A ROTARY DRIVE SHAFT, A NEEDLE BAR OPERATIVELY CONNECTED TO SAID ROTARY SHAFT FOR RECIPROCATION THEREBY, A MOTOR, A MAIN TRANSMISSION INCLUDING A MAIN DRIVEN SHAFT OPERATIVELY CONNECTED TO SAID ROTARY SHAFT AND MOVABLE MEANS RELEASABLY OPERATIVELY CONNECTING SAID MAIN DRIVEN SHAFT TO SAID MOTOR, THE IMPROVEMENT CONSISTING OF A SECONDARY TRANSMISSION ROTATABLE BY SAID ROTOR AT A LESSER SPEED THAN SAID MAIN TRANSMISSION, SAID SECONDARY TRANSMISSION INCLUDING A SECONDARY DRIVEN SHAFT PARALLEL TO SAID MAIN DRIVEN SHAFT, MEANS INTERCONNECTING SAID DRIVEN SHAFTS FOR ROTATION SIMULTANEOUSLY IN ONE DIRECTION, MEANS RELEASABLY OPERATIVELY CONNECTING SAID SECONDARY DRIVEN SHAFT WITH SAID MOTOR, AND MEANS OPERABLE BY SAID MOVABLE MEANS UPON MOVEMENT THEREOF TO RELEASE SAID MAIN DRIVEN SHAFT FROM SAID MOTOR TO CONNECT SAID SECONDARY DRIVEN SHAFT WITH SAID MOTOR, AND MEANS CONTROLLED BY SAID ROTARY DRIVE SHAFT FOR RELEASING SAID SECONDARY DRIVEN SHAFT FROM SAID MOTOR UPON POSITIONING OF SAID NEEDLE BAR AT A PREDETERMINED POSITION.

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