EP0856074B1 - Thread feed device - Google Patents

Description

The invention relates to a thread delivery device in the preamble of claim 1 specified Art.

From US-A-3 642 219 a thread delivery device of this type is known, that has been known as SFS / SFT for over 20 years is distributed before the applicant. U.S. Patent No. 3,642,219 there is only a hint of backstop between the top wall of the electric motor integrated in the storage drum and a rotary bearing of a feed element on the shaft fixed to the housing. The locking member works with the inner circumference of the storage drum on a relatively large Diameter together. With this thread delivery device used in practice SFS / SFT is the locking member made of plastic existing disc, in a fork-like, on the shaft anchored abutment between the running position and the Brake position is shiftable, namely by between one face of the disc and the top cover of the engine towing force generated by frictional contact. The abutment has a rising concave in the return direction Slideway for the disc, and at both ends of the track molded stops. In the running position, the comes loose Disk at least largely out of engagement with that on the inner circumference the braking surface provided for the storage drum. Kick a return of the storage drum, then the disc by the drag force along the slideway in a locked position relocated in which they pressed against the braking surface becomes. A return movement of the storage drum can be several Have causes. One in the feed area of the thread delivery device The provided thread scanner is spring-loaded and can after stopping the storage drum pull back the incoming thread and turn the storage drum back with the thread. Furthermore, the threads to be processed are mostly elastic, so that when stopping the storage drum the previously in tapered thread generated tension over the storage drum want to turn the thread back. Eventually, as a result, less favorable Circumstances and due to a slowdown of the motor create a counter torque that the storage drum want to turn back. The well-known backstop is technically complex, prone to wear and tear can especially when accelerating or at higher speeds cause unwanted vibrations, among other things because the disc has an extremely large diameter and works with a very large lever arm. The well-known backstop requires an almost exactly vertical arrangement of the thread delivery device, like they don't in some use cases is observable. Furthermore, structurally complex measures are required to burn the disc at its top To prevent the top wall of the motor contacting end face because the disc covers the top wall at a great distance from the Axis of rotation touches and therefore at high speed considerable friction is to be destroyed ..

The invention has for its object a yarn delivery device of the type mentioned at the beginning, in which a structural simple, easy-to-assemble backstop provided is reliable, wear-resistant with a long service life works and does not cause vibrations.

The object is achieved according to the invention in the claim 1 included features solved.

A noticeable influence at high speeds of the rotating element is eliminated due to the precisely adjustable towing force. This is particularly the case with modern thread delivery devices of considerable advantage, the rotation speed of which is approx. 20% can be higher than in the yarn delivery devices previously used. The braking surface can be set to a diameter which can be significantly smaller than the inside diameter of one if applicable, provided storage drum. Shows the rotating element the tendency to move backwards, then it will Locking element relative to the abutment in a smooth-running Rotational movement twisted by the drag force until its counter braking range thanks to the eccentric to the axis of rotation of the rotating element Circle outwards or inwards against the braking surface starts and blocks the return movement. The engagement in the blocking position takes place harmoniously and reliably, whereby a high braking power can be generated. Particularly important is that the locking member when restarting the rotary element easily and forcibly in the correct direction of rotation detaches from the braking surface and returns to the defined one Run position returns. The area of engagement between the Locking element and the braking surface can be designed over a large area, so that no excitation to vibrations in the thread delivery device arises. The backstop works reliably and with little wear with a long service life. General should be highlighted be that by the eccentricity and the diameter of the eccentric Circle, the characteristic curve can be predetermined precisely and can be optimally designed with which the backstop takes effect comes or is solved again.

According to claim 2, the backstop is optimal on one made small diameter, and in particular on a Diameter independent of the size of the storage drum.

The towing force can be exactly according to claim 3 Predetermine the dimension of the spring force. Conveniently it is pressed against the effect of gravity. The thread delivery device can therefore be installed in any position use without endangering the backstop. Further can be the area in which the locking member the towing surface contacted, relatively close to the axis of rotation of the rotating element set so that even at high speeds and strong accelerations the risk of burning the Blocking member is avoided, also by the ring shape, the one relatively low specific surface pressure per unit area enables and yet the sufficient towing force guaranteed.

Although the locking element automatically in the straight to prevent the blocking position required for the return is turned, without there being a special stop for the locking position need, it may be appropriate, according to claim 4 own To provide a stop for the locking member of an end locking position defines and excessive forces on the braking surface or the rotating element prevented.

The embodiment according to claim is particularly expedient 5, where the motor is fixed in the housing and the backstop well encapsulated from the working area of the storage drum is separated, in which dirt and lint are inevitable are. Since the locking member does not work with the Has inside diameter of the storage drum, the Select the diameter of the braking surface small enough to be high Speeds and strong accelerations in modern Thread delivery devices to rule out vibrations.

According to claim 6, the motor shaft over the co-rotating Backstop supported on the housing against a return.

Alternatively, the backstop makes according to claim 7 Rotary movement of the rotating element does not co-operate, but acts first with a return to the motor shaft over the for example block the braking surface attached to the motor shaft.

According to claim 8, the locking member works with a brake ring together who among other things provides a high braking effect due to the material.

Alternatively, a brake ring could be placed directly on or in the Locking member can be attached (claim 9).

A good backstop is also according to claim 10 reached a braking surface that is only structured, for example is knurled. This braking surface can be in a metallic Body arranged, for example in the housing or in a housing insert.

The embodiment according to FIG Claim 11. Plastic molded parts are characterized by high Shape accuracy, low weight and low wear out. Because the locking member by precisely adjustable spring force the towing surface is pressed, self-lubricating Plastic grades are used, which is a smooth Ensure rotatability of the locking element even over a long service life. The self-lubricating effect has a braking effect with the braking surface no adverse influence because there by the eccentric movement of the locking member a quick-acting forced intervention can be produced anyway.

The embodiment according to claim 12 is structurally simple and ensures low-wear work even over long periods Service life.

According to claim 13, the spring between the circular washer and the hub as an integral part of the backstop arranged. The projections or the circumferential bead are one Assembly aid for a pre-mintable unit because the The washer does not come off the ring flange under the force of the spring can fall off. The ring disk comes into operation normally not to the protrusions or to the peripheral bead.

Fig. 1

eine Seitenansicht, zum Teil im Schnitt, eines Fadenliefergeräts mit einer Rücklaufsperre,

Fig. 2

die Rücklaufsperre in einem Schnitt und in vergrößertem Maßstab, in der Laufstellung,

Fig. 3

eine axiale Draufsicht auf ein Widerlager der Rücklaufsperre,

Fig. 4

eine axiale Draufsicht auf ein Sperrglied der Rücklaufsperre, das zum Widerlager der Fig. 3 paßt, und

Fig. 5-8

schematische Detailvarianten der Rücklaufsperre.

Embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:

Fig. 1

a side view, partly in section, of a yarn delivery device with a backstop,

Fig. 2

the backstop in one section and on an enlarged scale, in the running position,

Fig. 3

an axial plan view of an abutment of the backstop,

Fig. 4

an axial plan view of a locking member of the backstop, which fits the abutment of FIG. 3, and

Fig. 5-8

schematic detailed variants of the backstop.

A thread delivery device F, preferably a thread delivery device F for a knitting machine, has a stationary housing G, on the underside of a storage drum T rotatably mounted which is about an axis of rotation X by means of a motor M in a predetermined direction of rotation to be driven. The Motor M can be switched on and off by means of signals, that of a scanning device D in a housing bracket 1 depending on the size of one on the storage drum T formed thread supply (not shown) are generated. The fed to the storage drum T by a not shown Supply spool coming thread (not shown) is through stationary Thread eyelets 2 passed and passed through a thread brake 3 under surveillance by a sensing element 5 to the extent the storage drum T. An inclined feed element V pushes each turn wound on the storage drum T. in Fig. 1 down, so that a thread supply of several Turns is formed. The thread intended for consumption is pulled off over the top of the storage drum.

A backstop R is provided in the thread delivery device F, namely between an upper cover wall 6 of the housing G and the upper end of a motor shaft H. The backstop R contains in the embodiment of Fig. 1 with the motor shaft H rotatably connected abutment W and a relative to it rotatably supported by a weak coil spring 4 upward loaded blocking element S, which is used for cooperation provided with a braking surface B in the top wall 6 Insert 7 is used, namely a return or a Return movement of the storage drum T or the motor shaft H prevent after a standstill.

2, the abutment W is an annular body A1 from a hub 8, which has a non-circular inner bore 9 attached to the matching end 10 of the motor shaft H in a rotationally fixed manner is a radial flange 11, which is a spring seat 12 defined, and an axial ring flange 14 with a cylindrical Outer peripheral surface 15, whose axis is opposite to X1 the axis of rotation X of the motor shaft H is eccentric. Further is in the annular flange 14 a cutout limited in the circumferential direction 17 molded, the (Fig. 3) two in the circumferential direction spaced stops 18 and 18 'defined. In the end area a circumferential bead 16 is formed on the ring flange 14.

That which is mounted on the abutment W relatively rotatably to this Locking member S is also an annular body A2, namely an annular disc 19 with an inner bore 20 and one cylindrical outer circumference 21, which is used for cooperation with the Braking area B is determined. The central axis of the peripheral surface 21 is correct in the running position of the backstop R with the axis of rotation X at least approximately. The central axis the inner bore 20, however, coincides with the axis X1, which is eccentric to the axis of rotation X. In one face the annular disc 19 is concentric with the peripheral surface 21 Spring receiving groove 13 formed for the coil spring 4, the other end in the spring seat 12 of the Flange 11 supports and the annular disc 19 with at least a part 22 of its other end face against a housing-fixed Drag surface 23 presses. In the inner bore 20 the annular disc 19 a nose 26 protrudes inwards, 4 stops 27 and 27 'defined with the Stops 18 and 18 'for setting a running position and cooperate in a locked position. The braking surface B and the Trailing surface 23 are included in the insert 7, which in the Cover wall 6 is set. It is conceivable the tow surface 23 and to arrange the braking surface 21 directly in the top wall 6.

In this embodiment, the braking surface B is on one Brake ring 24 made of a frictional material, such as rubber, elastomer or another plastic, provided in a Version 25 of insert 7 is set. In the in Fig. 2 shown running position, in which the backstop R the normal rotation of the motor shaft H is not affected the peripheral surface 21 and the braking surface B a radial Game Y provided.

The two ring bodies A1, A2 are expediently plastic parts, for example injection molded parts. The insert 7 can consist of metal, for example steel. The braking surface B could also be directly from the inner peripheral surface of the socket 25 are formed, which then expediently a roughened Surface structure, for example knurling, has. The peripheral surface 21 could, if necessary, be structured to increase the frictional engagement.

In the running position, the locking member S sits in accordance with FIG the rotational position shown in FIG. 4 on the ring flange 14 of the abutment W, which is in the rotational position shown in Fig. 3 located. The nose 26 is at the stop 27 ' Stop 18 'on. The peripheral surface 21 is then essentially concentric to the axis of rotation X and is the braking surface B (Fig. 2) with the radial play Y opposite. 3 and 4 counterclockwise motor shaft H takes the locking member S over the abutment w without it the braking surface B comes into contact. Because of the pressure the spring 8 becomes the locking member S against the drag surface 23 pressed so that a permanent Towing force in the locking element S acts in a clockwise direction stops with the stop 27 'at the stop 18'.

After the motor shaft H has come to a standstill, in the event of a Return it (rotary movement of the motor shaft H in FIGS. 3 and 4 clockwise) by contact with the towing surface 23 on the locking member S a towing force counterclockwise generated. This drag force rotates the locking member S relatively to the abutment W on the ring flange 14, the outer peripheral surface 21 of the locking member in a circumferential direction limited counter braking area is shifted to the outside and on the braking surface B starts. Another return movement of the Motor shaft H is prevented in this way. Possibly even the stop 27 of the nose 26 comes to rest against the stop 18 of the ring flange 14.

If the motor shaft H is driven in the desired direction again, i.e. 3 and 4 counterclockwise, then the towing force on the towing surface 23 holds that Locking member S back, the peripheral surface 21 is from the braking surface B solved and centered again with respect to the Axis of rotation X.

A kinematic reversal is conceivable in such a way that the Ring body A2 on the top wall 6 or in the insert 7 rotatably is mounted, however, the ring body A1, the motor shaft H or the end 10 (which then has a cylindrical outer circumference has) rotatably comprises, expediently again with a radial play. The end surface 23 'then serves as the drag surface. the motor shaft H with the end face 22 'of the ring body A1 works together under the pressure of spring 4. The braking surface B can then either on the outer circumference of the motor shaft H or also provided in the inner bore 9 of the ring body A1 his. In this case, the ring body A2 forms the abutment W and the ring body A1 the locking member S.

5 is the embodiment shown in FIGS. 2, 3 and 4 schematically shown, in which the locking member S on the outside the abutment W is rotatably mounted and with the braking surface B works together.

In Fig. 6 the kinematic reversal is indicated, in which the abutment W arranged outside on the locking member S and (indicated by crosses) is rotatably held. The locking link S is rotatable relative to the motor shaft H. The blocking effect is between the inner bore 9 and the braking surface B or brought about the outer circumference of the motor shaft H.

7, the schematic of the 5 is on the outer circumference 21st the locking member S is a limited braking surface area in the circumferential direction 21 'preformed, the to cooperation with the braking surface B is determined.

8 is similar to the principle of operation 6 corresponds to the inner bore 9 of the Locking member a limited inward direction protruding braking surface area 9 'formed, for cooperation with the braking surface B, in the present case the motor shaft H, is determined. The abutment W is here Ring body with a non-circular outer circumference, which is the definition of the Abutment simplified. 7 and 8, the braking surface area 21 'and 9' also have a curvature, the Center of curvature not with the center of the cylinder surface 21 or 9 coincides, i.e. the braking surface area 21 ' or 9 'could be curved more or less by one to achieve special braking effect.

The backstop shown in Fig. 1 could also be below of the motor M may be arranged. Conveniently, the Backstop R however encapsulated and out of the influence of Soiling or fluff when processing thread material are inevitable, be separated. The diameter, on which the locking member interacts with the braking surface B, is advantageously much smaller than the diameter the storage drum T or its inner diameter. The size the contact area between the locking member and the Drag surface 23 or 23 'should be chosen so that under the pressure of the spring 8 just sufficient for the function Tractive force guaranteed, however, overheating or a burning of the locking member is excluded.

Claims (13)

1. Yarn feeder (F), particularly for knitting machines, having a stationary housing (G) and a rotational element (T) which can be driven in a rotational direction by means of a motor (M) which can be switched off and switched on, said rotational element (T) being supported on the housing and serving to wind a yarn into a yarn store consisting of a plurality of windings on a storing surface from which the yarn can be withdrawn for consumption overhead, furthermore having a sensor device for detecting movements of the boundary of the yarn store varying in withdrawal direction and for generating signals to switch on or switch off the motor, and having a mechanical backturn-detent-mechanism for hindering a backturn movement of the rotational element, said mechanism containing a detent member (S) which is moveable in relation to a counter-member (W) between a running position defined by an abutment and a blocking position, for engaging a braking surface in the blocking position, said detent member (S), upon a rotational movement of the rotational element in each sense of rotation, being adapted to be brought into the running position or into the blocking position with a drag power generated by friction contact, said drag power displacing the detent member in response to the sense of rotation in relation to the counter-member, characterised in that the counter member (W) and the detent member (S) are two ring bodies which are set within each other and are rotatable in relation to each other about the rotational axis (X) of the rotational element (T), that the mutual area of engagement between the two ring bodies is at least a section of a circle being eccentrically arranged about the rotational axis of the rotational element, and that the detent member (S) for co-operation with the braking surface (B) is provided at its peripheral surface (21) with a braking range (21') being limited in its extent in circumferential direction.
2. Yarn feeder as in claim 1, characterised in that the diameter of the braking surface (B) is significantly smaller than the inner diameter of the storing drum (T).
3. Yarn feeder as in claim 1, characterised in that a front surface of the ring body (A1 or A2) defining the detent member (S) can be pressed by spring force (4) approximately parallel to the rotational axis (X) of the rotational element against a drag surface (23, 23') being fixed in the housing or fixed at the rotational element.
4. Yarn feeder as in claim 1, characterised in that in addition to the abutment defining the running position an abutment for limiting the relative rotational movement between the ring bodies is provided for defining a blocking position, preferably a final blocking position.
5. Yarn feeder as in at least one of claims 1 to 4, characterised in that the rotational element is a motor shaft (H) of the motor (M) arranged inside housing (G), said motor shaft (H) fixedly carrying a storing drum (T), and that the backturn-detent mechanism (R) is provided between a housing wall (6) facing away from storing drum (T) and the motor (M), preferably on an extension (10) of the motor shaft (H).
6. Yarn feeder as in claim 5, characterised in that the ring body (A1) defining the counter-member (W) is fixedly arranged on the motor shaft (H), that the ring body (A2) defining the detent member (S) is supported at the exterior of the counter-member ring body, and that the braking surface (B) outside the detent member (S) as well as the drag surface (23) facing a front surface of the detent member (S) are provided in the housing wall (6), preferably in an insert (7) held in the housing wall (6).
7. Yarn feeder as in claim 5, characterised in that the ring body (A1) defining the counter member (W) is fixedly held in the housing wall (6), preferably in a seat of the housing wall (6), that the ring body (A2) defining the detent member (S) is journalled inside in the counter member-ring body, and that the braking surface (B) inside the detent member (S) and the drag surface (23') facing a front surface of the detent member (S) are each provided on the motor shaft (H), preferably in an insert held by the motor shaft (H).
8. Yarn feeder as in claim 6 or 7, characterised in that the braking surface (B) is formed by a braking ring (24) made of a friction-active material, e.g. rubber or elastomer, said braking ring surrounding the detent member (S) or being surrounded by the detent member (S), preferably with a radial clearance (Y) in the running position.
9. Yarn feeder as in at least one of claims 1 to 7, characterised in that a braking ring (24) made of friction-active material is provided on the outside or within the detent member (S).
10. Yarn feeder as in at least one of claims 1 to 7, characterised in that the braking surface (24, 25) is provided with a surface structure, e.g. a knurling.
11. Yarn feeder as in at least one of claims 1 to 10, characterised in that both ring bodies (A1, A2) are form parts of plastics.
12. Yarn feeder as in claims 5 and 6, characterised in that the counter-member ring body comprises a hub (8) fixedly secured to the motor shaft (H), preferably by means of a polygonal inner bore (9), said hub (8) having an axial annular flange (14) with a cylindrical outer peripheral surface (15) excentrically arranged about the rotational axis (X) of the motor shaft (H) and a radial flange (11) defining a spring seat (12), and that in the outer peripheral surface (15) of the annular flange (14) two circumferentially spaced-apart abutments are formed which are retracted in relation to the outer peripheral surface or protrude over said peripheral surface (15), and that the detent member-ring body is an annular disc (19) with a cylindrical outer peripheral surface (21) and an eccentric inner bore (20) which is eccentrically arranged in relation to the centre of the outer peripheral surface (21) and the inner diameter of which corresponds to the outer diameter of the ring flange (14) of hub (8), and that the inner bore (20) has arranged therein an inwardly projecting nose (26) or a diameter enlargement which is limited in circumferential direction.
13. Yarn feeder as in claim 12, characterised in that in the front surface of the annular disc (19) facing the flange (11) a spring receiving groove (13) for a coil spring (4) is provided concentrically about the rotational axis (X) of the motor shaft (H), that the other end of the spring (4) is resting on the spring seat (12) of flange (11) of the hub (8), and that in the region of the free end of the ring flange (14) projections or a circumferential enlargement (16) is/are formed which slightly project(s) beyond the outer diameter of the ring flange.

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