US1377018A - Motor-drive for sewing-machines - Google Patents

Description

H. MAIMIN.

MOTOR DRIVE FOR SEWING MACHINES.

APPLICATION FILED DEC-8, I919. 1,377,018.

Patented May 3, 1921.

2 SHEETS-SHEET 1.

lrromaqs H. MAIMIN.

MOTOR DRIVE FOR SEWING MACHINES.

APPLICATION FILED DEC-8. 1919.

1,377,018. v Patented May 3,1921.

2 SHEETS-SHEET 2.

3 vwc ntoz ZMIC, ekjjm mt/JAB PAT HYIAN MAIMIN, OF NEW YORK, N. Y.

MOTOR-DRIVE FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented May 3, 1921.

Application filed December 8, 1919. Serial No. 343,216.

To all whom it may concern:

Be it known that I, HYMANMAIMIN a citizen of the United States, residing at New York cit in the county of New York, State of New ork, have invented certain new and useful Improvements in Motor-Drives for Sewing-Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to motor drives for sewing machines.

Sewing machines, particularly those that are to be used continuously, are usually driven by a small electric motor mounted on the frame or table of the machine and connected in permanent operative relation to the driving wheel of the machine by means of a belt or by a friction pinion which is pressed against the driving wheel by a spring. The motors are usually provided with rheostats for preventing a sudden rush of current when the motor is started under load, and also to permit the speed of the machine to be controlled while it is in operation. The price of a suitable rheostat is a substantial part of the total cost of an equipment, and

' this piece of apparatus is the source of most of the troubles that arise in connection with motor drives for sewing machines. These and other disadvantages attending the employment of rheostats in connection with sewing machine equipments have long been recognized, and various arrangements have been proposed to eliminate them by driving the motors continuously and bringing them into operative relation to the moving elements of the sewing machine whenever it isdesired that the latter be driven.

In some of the arrangements that have been proposed for this purpose, the motors are fixed upon the tables of the sewing machines and connected to friction wheels which are adapted to be swung into engagement with the hand wheels of the machines whenever it is desired to operate the latter. These arrangements, however, require the use of extra members, and in some cases, owing to the movement of the swinging members upon which the friction wheels are carried, there is a change in the tension of the driving belt. Arrangements have also been proposed in which the motors are pivotally mounted in such a manner that they may be moved bodil to bring friction wheels mounted on the1r shafts into engagement with the hand wheels of the machines whenever it is desired that the latter be operated, but these arrangements are open to the objection that the speed at which the machlne is driven from the motor depends upon the pressure with which the friction wheel of the motor is held against the hand wheel of the machine, and this pressure is subject to considerable variation on account of changes in the force exerted by the operator upon the treadle usually provided for controlling the position of the motor. For'most rapid production, it is generally considered that best results are obtained if machines are normally operated at a predetermined speed, and the operator is required to conform to. the speed of the machines. Such a practice cannot be followed with any degree of certainty if the speed of the machine is as directly under the con trol of the operator as it is in the arrangements mentioned above wherein slight variations in the effort expended by the operator to hold the motor in driving relation to the machine result in considerable varia tions in the speed of the latter.

It is an object of this invention to provide a motor drive for sewing machines in which the motor shall be held in operative relation to the machine by the weight of the motor, but may be conveniently taken out of such relation whenever it is desired to stop the machine. The arrangement therefore provides that under normal conditions of operation the motor will be held in operative relation to the driving wheel of the machine in such a manner that the speed at which the machine is driven shall be of a predetermined amount and will not be subject to variations inthe effort expended by the operator as are prior arrangements of this general character. At the same time the arrangement permits the operator to change the speed of the machine from time to time as may be required, but this regulation necessitates a special act on the part of the operator which will not naturally be performed under normal conditions of operation.

In accordance with the invention the mo tor is pivoted adjacent a wheel or pulley of the machine in such a manner that it may be oscillated to be thrown into or withdrawn from operative relation with the wheel. Power may be transmitted from the motor to the machine by means of a friction pulley -on the shaft of the motor which is brought into engagement with the hand wheel of the machine by allowing the motor to fall toward the machine, or a pulley on the shaft of the motor may be connected by a belt to a driving pulley on the shaft of the machine, in which case the motor will be arranged to fall away from the machine to apply tension to the driving belt. For most conventient operation the position of the motor should be under the control of a foot of the operator in order that his hands may be free for manipulating the work. This is accomplished by providing a treadle having a flexible or lost-motion connection to the motor and which is normally actuated by a spring to swing the motor in such a manner as to disengage the friction pulle from the hand wheel or slacken the driving belt, as the case may be. When the effect .of the spring is overcome by pressure upon the treadle, the motor will swing by gravity intoposition to transmit power to the machine, and preferably the arrangement is such that the normal movement imparted to the treadle will be sufficient to slacken the flexible connection so that the motor isiheld in operative relation to the wheel of the machine by its own weight. The arrangement does, however, permit the speed of the machine to be controlled, for if the treadle is not pressed downwardly to its full extent, the flexible connection will remain taut and balance the weight of the motor, so that the pressure with which its friction pulley is held against the hand wheel of the machine will be lessened, or in case a belt drive is employed, the effect of the weight of the motor in producing belt tension will be partly overcome. In either case there v will be some slip in the driving connections, which will result in decreased speed of the machine. The natural condition of operation will be such that the operator will find it most convenient to hold the treadle completely depressed so as to release the flexible connection sufficiently to free the motor and permit it to be held in operative relation with the machine by its own weight. It will be somewhat more tedious for the operator to hold the treadle in partially depressed condition to produce a slower speed of the ma chine.

The particular nature of the invention, as well as other objects and advantages thereof, will appear more clearly from a description of certain preferred embodiments as illustrated in the accompanying drawings, in which y a Figure 1 is an end elevation of a sewing machine showing the motor arranged for a friction drive;

Fig. 2 is an elevation of the apparatus viewed from the opposite direction and with part of the frame of the machine broken awa Fig 3 is a side elevation of the frame of the machine with the device in place thereon Fi 4 is a detailed view in section along the line 4-4 of Fig. 3; and a Fig. 5 is an'end elevation showing the device arranged for a belt drive.

The sewing machine illustrated somewhat diagrammatically in the drawings, comprises a table 10 carried upon standards 11 and serving as a support for the frame 12 which comprises a vertical portion and a horizontal portion at the outer end of which there is a head 13 within which the mechanism for reciprocating the needle is mounted, this mec anism being driven by a shaft carrying the usual belt pulley 14 and hand wheel 15. Mounted adjacent the hand wheel is an electric motor 16 which as shown herein is carried upon a bracket like that disclosed in my copending application, Serial No. 343,215, filed Dec. 8, 1919, but it will be understood that the motor-may be supported adjacent the machine wheel in any other suitable manner.

The supporting bracket shown herein comprises a member 17 having at its inner end upper and lower extensions 18 and 19,-respectively, adapted to fit over the top and bottom of the horizontal arm of the frame 12. The supporting member is bent outwardly as indicated in Figs. 1 and 2 toclear the machine wheel and bring the motor in proper relation to this wheel. In a supporting member constructed as above described,

the weight of the motor upon the end of the member will produce a turning moment which will be opposed by the engagement of the upper and lower extensions with the frame so that the member may be held in place upon the frame without any otherment or dislodgment due to the vibration of the motor or from any other cause. This auxiliary supporting member consists of a strip 0 metal or other suitable material having a fiat upper portion adapted to be seated upon the top of the machine frame and provided with apertures through any one of which the usual spool spindle 21 may be passed to hold the supporting member more securely in place upon the frame. The depending portion of the strip is turned upwardly to form a hook within which the main supporting member is seated as shown most clearly in Fig. 3.

The outer end of the supporting member 17 is bent at right angles to form an ear 22. Another ear 23 may be formed by cutting a portion of the supporting member 17 and bending it at right angles. The ears carry a pin 24 which passes through lugs associated with the motor casing. Placed upon the pin 24 between the motor lugs is a split clamp 25 which serves to hold the motor in proper position longitudinally of the bracket.

In the arrangement shown in Figs. 1, 2 and 3, the shaft of the motor is provided with a friction pulley 26 adapted to be held in engagement with the hand wheel 15 of the machine by the weight of the motor, it being understood that the supporting bracket is so constructed as to bring the pivot pin 24 in proper relation to the Wheel of the machine to permit the motor to fall into operative relation to the wheel of the machine as shown most clearly in Fig. 1.

For the purpose of withdrawing the motor from operative relation to the wheel of the machine, there is provided a treadle 27 which may be placed in convenient position to be reached by the operators foot. A flexible connection 28 is attached at one end to the treadle and at the other end to a link 29 adapted to be secured to a lug 30 projecting from the motor casing. Preferably the flexible connection 28 should be adjustably attached to the link 29 as by means of a clamp 31, or other suitable device. Beneath the treadle is a spring 32 which normally raises the treadle and through the connection 28 lifts the motor out of engagement with the machine wheel, as indicated in Fig. 2. It is intended that the elements of the apparatus shall be so arranged that when the treadle is depressed to its maximum extent the flexible connection 28 will become slack enough to permit the friction pulley of the motor to be held in engagement with the wheel of the machine by the weight of themotor, in which case the motor shaft and the pivot pin 24 will-lie upon a line A..

l/Vith the arrangement described above a sudden release of the treadle might cause the motor to be thrown over to the other side of its pivot, whereas it should move only as far as indicated by the line B, in order that it may fall into engagement with the machine wheel when-the treadle is again depressed. In order to prevent any overthrow of the motor, the ear 22 may be provided with an aperture 33 within which may be inserted a pin 34 to engage the corresponding lug of the motor and act as a stop for the latter.

In some cases it may be desirable to employ a belt drive between the motor and the sewing machine, and in order that the device shall possess the greatest range of utility provision for such a drive is 'made. When a belt drive is employed the motor should be arranged to fall away from the wheel of the machine as shown in Fig. 5. It is therefore necessary to attach the con nection leading to the treadle to the other side of the motor. For this purpose I provide a lug 35 corresponding to lug. 30 but arranged upon the otherside of the pivot lugs of the motor. By removing the stop pin 34 the motor may fall away from the machine and be operatively connected to the latter by a belt 36 passing over the pulley l4 and the friction pulley 26 on the motor shaft. When such a change is made it is necessary to shift the motor lengthwise of the pivot pin 24 to bring the pulley on its shaft into alinement with the pulley 14. This may be done b changing the position of'the clamp 25. ith the apparatus arranged in Fig. 5, the spring 32 acting upon the treadle tends to swing the motor toward the machine and slacken the belt sufficiently to prevent it from transmitting any power from the motor to the machine.

s in the case of the frictiondrive arrangement, means should be provided for preventing the motor from being thrown over its pivot point. For this purpose the bracket ear 22 may be provided with a second hole 37 into which the pivot pin 34 may be inserted to be engaged by one of the pivot lugs of the motor and limit the inward movement of the latter. When the treadle is depressed into the dotted line position of Fig.

ditions the flexible connection will be sufficiently slack so that the belt tension produced by the weight of the motor will not be lessened by the opposing effect of the spring 32. The motor will thus be free -to drive the machine at the predetermined speed regarded as suitable for most eflicient operation. In case it is desired to lessen the speed, the treadle will be lifted sufficiently. to take up the slack in the flexible connection and then pull the latter enough to partially overcome the effect of the weight of the motor upon the tension of the belt. There will thus be produced between the belt and the pulleys to which it is connected, a certain amount of slip which will result in a decreased speed of operation of the machine without changing the speed of the motor by means of a rheostat or similar device.

The invention thus provides a motor drive for sewing machines which is of simple construction and eliminates the use of delicate and expensive instruments such as rheostats for controlling the speed of the motor. At the same time the arrangement is one that under normal conditions of operation insures that the sewing machine shall be driven at maximum speed so that the efliciency of the operator is not lessened. It is, however, possible to produce changes in the speed of the machine by shifting the position of the motor, but such changes require that the operator hold the treadle in an intermediate position which is not only less comfortable,

ut renders it more difiicult to maintain a 5 constant speed of the machine than when the treadle is in fully depressed position, which is in the nature of a stop position, and may be maintained by the operator with compara tivcly little effort. In other words, the usual condition of the machine will be either one in which the driving motor is held entirely out of operative relation to the machine by the spring acting upon the treadle, or one in which the motor is held in operative relation to the machine by its weight independently of the spring, but it is possible to producea third condition in which the motor is held in operative relation under the bal anced effect of its weight and the force ex erted by the spring.

While certain preferred embodiments of the invention have been shown and described, it will be understood that various changes in the details of construction may be made without departing from the principle of the invention as defined in the appended claims.

I claim 1. In a sewing machine provided with a r driving wheel, the combination of a pivotally mounted motor adapted to be held in operative relation to the wheel of the ma-. chine by its own weight, and means for antomatically lifting the motor out of operative relation to the wheel of the machine movable member, means for actuating the movablemember to move the motor out of -operative relation to the driving wheel of the machine and adapted to be overcome by the operator to release the connection to permit the motor to be held in operative relation to the driving wheel of the'machine by its own weight.

3. In a sewing machine provided with a driving wheel, the combination of a supporting member, a motor pivotally mounted on the supporting member, a movable member, a flexible connection between the motor and the movable member, means for actuating the movable member to move the motor out of operative relation to the driving wheel of the machine and adapted to be overcome by the operator 'to slacken the flexible connection sufliciently to permit the motor to be held in operative relation to the driving wheel of the machine by its own weight independently of the effect of the actuating means.

4. In a sewing machine provided with a driving wheel and a motor mounted to swin about a pivot displaced from its center 0 gravity, the combination of means for controlling the position of the motor, comprising a spring-pressed treadle and a connection between the treadle and the motor to permit the motor to be lowered into operative relation to the wheel of the machine by pressure applied to the treadle to overcome the effect, of the spring.

5. In a sewing machine provided with a shaft having a driving wheel thereonand a pivotally mounted motor adapted to swing about an axis parallel tothe shaft of the machine, the combination of means for controlling the position of the motor, comprising a spring-pressed treadle and a lost motion connection between the treadle and the motor adapted to permit the weight of the motor to hold it in operative relation to the driving wheel of the machine independently of the effect of the spring when the treadle is actuated in a direction to overcome the efiect of the spring upon the connection.

6. In a sewing machine provided with a driving wheel, the combination of a supporting member, a motor pivotally mounted on the supporting member, a treadle, a spring for actuating the treadle, and means by which a pull may be exerted upon the motor to lift it out of operative relation to the wheelof the machine when the treadle is moved in one direction by the spring and which will allow the motor to fal into operative relation to the wheel of the machine when the treadle is moved in the opposite direction.

7 In a sewing machineprovided with a driving wheel and a pivotally mounted motor, the combination of a flexible member connected at one end to the motor and a spring-pressed treadle to which the other end of the flexible member is connected and adapted when in one extreme position to hold the motor out of operativerelation to the machine wheel, and when in another extreme position to release the flexible member sufficiently to permit the motor to remain in operative relation to the wheel of the machine under the influence of its own weight and independent of the lifting effect of the spring.

8. In a sewing machine provided with a driving wheel, the combination of a supporting member, a motor pivotally mounted on the supporting member in such a manner that it may fall toward or away from the wheel ofthe machine, a swinging member, a flexible member having one end connected to the swinging member and adapted to be selectively connected at its other-end to the motoron opposite sides of the pivot swinging mem 9. In a sewing machine provided with a driving wheel, the combination of a supporting member adapted to be attached to the frame of the machine and provided at its outer end with a pivot, a motor mounted upon the pivot, a treadle, a flexible connection having one end attached to the treadle, means by which the other end of the flexible connection may be selectively attached to the motor on either side of the pivot, a spring for actuating the treadle to swing the motor about its pivot, and a stop mem-.

ber associated with the supporting member and adapted to be selectively arranged on the side of the motor ivot corresponding to that which the flexi le member is connected, to limit the movemnt of the motor when 1t is swung by the spring.-

10. In arsewin machine provided with a frame, a hand w eel and a belt pulley the combination of a supporting member adapted to be attached to the frame of the machine, a motor provided with a shaft adapted to receive a power transmitting ulle said motor being pivotally and sl idab y mounted upon the supporting member in such a manner that it may fall toward or away from the wheel of the machine, means for adjusting the position of the motor longitudinally of the supportin member so that the power transmitting pul ey upon the shaft of the motor may be selectively alined with thehand'wheel and the belt pulley of the machine, a swinging member, a flexible member havin one end connected to the Eer and adapted to be selectively connected at its other end to the motor on opposite sides of the pivot of the motor, and means for actuating the swinging member to rotate the motor in a direction opposite to that in which. it would swing about its ivot under the influence of its weight, sairf means being adapted to be overcome by the operator to release the flexible member to permit the motor to' fall toward or away from the machine depending upon the point to which the flexible member is connected to the motor.

11. In a sewing machine provided with a driving wheel, the combination of a pivotally mounted motor adapted to be held in o erative relation to the wheel of the ma- 0 ine' by its own weight, and a sprin for overcoming the weight of the motor w ereby it may be lifted out of operative relation to the wheel, said spring being adapted to be overcome by the operator to permit} the motor to be held in o erative relation to the machine independent y of the lifting effeet of the spring.

12. Driving mechanism for a sewing machine comprising the combination of a motor held in operative relation to the machine by the action ofa predetermined force, means orposing this force normally nullifying its e ect and holding the motor in inoperative position, andlmeans independent of the. motor for counteracting this opposin means and permitting the predetermine force to move the motor into operative position.

13. Driving mechanism for a sewing machine comprising the combination of a motor desi ned to be held in operative relation to t e machine by its own weight lifting means normally holding the motor 1n inoperative position, and means independent 0 the motor for counteracting the effect of the lifting means and permittlng the motor to fall into operative position.

In testimony whereof I aflix my signature.

' HYMAN. MAIMIN.

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