DE78576C - Knife gate valve for sewing machines - Google Patents

Description

IMPERIAL

PATE N TA MTAt

GREAT

: ^ Sewing machines.

The knife gate valve for sewing machines, mainly sole sewing machines, consists of the The main thing is that a medium-toothed foot is pressing on the workpiece at the appropriate time Transport lever, which can be raised and lowered on a machine head Rail or sleeve is pivotably mounted, and which for the purpose of advancing the workpiece performs a square movement each time.

According to the present invention, the drive device for the swingable transport lever respectively. for the rail carrying this lever so arranged that the excavation the lever of the work piece depending on the nature of the material of the work piece can be larger or smaller, so that, for example, a higher one for softer fabrics Excavation, for harder materials a smaller excavation can occur, regardless of the larger or smaller feed movement of the transport lever (stitch length).

The four-stroke movement consists of the vibration of the transport lever Forward and backward and in up and down caused by shifting the rail together with the transport lever of the material pusher, namely the advance and retraction of the transport lever by the thumb lift and by spring pressure causes during the rise and fall of the rail together with the transport lever by adjustable Friction thrust and is caused by adjustable spring balancer.

The friction thrust is set in rotary motion by one of the machine drive shaft Friction shoe produced by the latter temporarily having a rotatably mounted friction disc offset in partial rotation, which in turn causes an excavation of the rail together with the transport lever by the fact that one of the rail protruding guide roller in a provided in the friction disk surface Slotted hole engages, through the rotation caused by the friction shoe a lifting by rail and transport lever at the appropriate time.

The guide roller on the rail is adjustable in such a way that it changes Position in the slotted hole of the friction disk a corresponding to the thickness of the workpiece larger or smaller excavation of the knife gate takes place. Accordingly is also the descent of the fabric slide changeable, namely by a spring, which is the peculiarity of the material of the workpiece correspondingly more or less tensioned or loosened whose effect is temporarily canceled entirely by a brake.

The new knife gate valve is particularly suitable for sewing machines equipped with horn Shoe and boot manufacture and is the same on the accompanying drawing in two front views omitting the cover plate, namely in Fig. 1 in the working position and in Fig. 2 shown in high position, for example as much of a horn sewing machine drawn as is necessary to explain the present invention.

Fig. 3 shows the mechanism which actuates the knife-gate valve in a top view.

α is the needle bar, which is moved vertically up and down and carries the needle b , and c is the horn head, on and over which the

Work piece c ¹ rests. ^{The interchangeable toothed foot rf 1} on a lever rf acts on the work piece and pushes the work piece forward according to the stitch length or holds it on the horn while sewing.

The lever d is swingably arranged at e ¹ on a correspondingly 'shaped rail e , which is mounted and guided in the sewing machine head parts α ¹ and a ^{1 so} as to be displaceable in the vertical direction. This rail e is pulled down by the tension spring e ″ , so that the toothed foot rf ^{1 is} pressed down onto the workpiece.

In order to impart the feed movement to the workpiece, the lever rf must be swung out, which ^{is done by a thumb / 1} which is seated on a disk / which acts against the upper end of the lever; The latter is keyed onto the machine drive shaft g and is rotated by the latter with the thumb, so that the thumb acts against the upper end of the lever rf at the appropriate time so that its lower end swings ^{forward with the foot rf 1} , thus the work piece is pushed away on its pad. The swing back of the lever rf takes place after it has been lifted from the workpiece with the rail e in the manner indicated below, by the pressure of a spring h, which sits on a screw adjustment device i , which is on the one hand in a bracket e attached to the rail e ³ finds movable storage, while on the other hand to the lever rf. is articulated. By turning the knurled knob i ¹ , the distance of the lever rf from the thumb f ^{l can be} changed and accordingly the swing of the lever rf can be increased or decreased depending on the desired stitch length.

Behind the disk / on the shaft g sits a second disk / °, on the periphery of which the end of the lever k, which is equipped with guide rollers, rests ^{eccentrically at A: 1.}

The periphery of the disc / ⁰ is provided with thumb-like elevations / *, so that when the guide roller runs up on it, the eccentric end of the lever k clamps against the rail e and the same at a certain time to cancel the action of the tension spring e ² in its upper one Leadership holds fast; when the guide roller has exceeded the elevations, the lever k releases the rail e again and the spring e ² comes into effect.

In order to achieve the occasionally required lifting of the rail e together with the lever rf, a friction shoe / is attached to the rear surface of the disc / ⁰ , which is set in rotation ^{with the discs // 0;} in this case, the shoe engages at the appropriate time via a friction disk m, which is rotatably mounted on the machine head part.

The disc m is provided with a slotted hole m ¹ , into which a guide roller m ² engages, which is adjustably fastened in a slotted hole of the lug e ^{3 of} the rail e _f

During the engagement of the circulating shoe I in the disk m ^{, the latter is partially rotated, whereby the lifting of the latter is effected against the spring e 2} as a result of the specified connection of the disk with the rail e, as FIG. 2 illustrates, in which also it can still be seen how the lever k receives the rail e in the upper position through its braking effect.

By adjusting the roller to ² in the bracket e ³ and consequently also in the slotted hole m ^{1 of} the disc m , the excavation of the rail e and lever rf can be changed according to the material of the workpiece.

A hand lever arranged in a known manner can also be present on the head cover plate in order to be able to conveniently lift and lock the rail e and lever rf at any time by hand, as is known.

From the raised position (Fig. 2) the rail e along with lever rf is pressed down again on the work piece by the tension spring e ² , as well as the disk m is thereby brought back into its initial position as soon as the braking effect of the lever k by its falling off Rolls in an interruption of the thumb / * stops.

By a more or less strong relaxation or tension of the spring e ² , the decline of the rail e can be changed respectively. the impact of the foot rf ^l on the workpiece can be weakened or intensified.

In the present knife gate valve, the work process always takes place in four-stroke cycles, namely in the order that first 1. the spring e- the rail e with the lever rf respectively. whose foot rf 'presses firmly on the work piece, which after the previous stitch formation 2. is advanced by the stitch length by the thumb f ^{1 acting against the lever rf;} then 3. the rail e is raised by the friction drive / m and 4. the lever rf is swung back again by the pressure of the spring h , whereupon the game repeats itself, beginning with 1..

This four-stroke can, as shown in the six graphical representations in the enlarged The scale can be seen in its upward and downward movement thanks to the adjustable friction drive and can be changed in its advance.

As a result of the rolling movement carried out by it, the frictional drive Im offers the most reliable guarantee that the material slide is always correctly lifted.

Claims (2)

The friction disc can be set up in such a way that it Wear of the attack surface can be adjusted in order to present the friction shoe with a new friction surface. With regard to the four-stroke or square movement to be carried out by the feeder lever, it should also be noted that in the movement phases indicated by 3 and 4 in the schematic figures, the period of raising and lowering of the lever can be so short that these phases do not describe the indicated path. These phases then take place instead of at right angles 3 and 4, in a curve which forms the transition of the lever movement from the end of the advance movement 2 to the beginning of the downward movement 1. The smaller part of the thumb f °, denoted by f *, can therefore be omitted, so that the braking effect disappears after the lever d d1 is lifted 3 and this movement 3 coincides with the return movement 4, so that a curve movement instead of that at right angles movements 3 and 4 shown. Patent claims: 1. A material pusher with a square or square-like movement for footwear sewing machines, in which the lifting of the lever which causes the material feed ¹ ) from the workpiece can be enlarged or reduced according to the softness or hardness of the surface of the respective workpiece, in that the lifting of the by means of a spring fe ² ) pressed onto the work piece from the latter by a friction disc fm) which is temporarily set in short rotation by a rotating friction shoe (I) and which is adjustably connected to the rail fe) carrying the knife lever (dd ¹ ). 2. A material valve of the type characterized in claim 1, in which the displacement of the material valve takes place by thumb washer (ff) and spring (h) , while the material valve is in its raised position by a braking device fff acting on the rail fe) carrying the material valve * kk ¹ ) is held until it has returned to its original position. 1 sheet of drawings.