EP0856074A1

EP0856074A1 - Thread feed device

Info

Publication number: EP0856074A1
Application number: EP96934622A
Authority: EP
Inventors: Per Ohlson; Kurt Arne Gunnar Jacobsson
Original assignee: Memminger IRO GmbH
Current assignee: Memminger IRO GmbH
Priority date: 1995-10-16
Filing date: 1996-10-10
Publication date: 1998-08-05
Anticipated expiration: 2016-10-10
Also published as: CN1200152A; ES2142621T3; CN1065933C; KR100282545B1; DE59604253D1; EP0856074B1; KR19990064260A; TW475602U; US6015109A

Abstract

A thread feed device intended in particular for knitting machines has a stationary housing (G), a rotary element driven by a motor (M) for winding a thread and a mechanical rewind lock for the rotary element including a locking member capable of sliding on an abutment (W) between a running position and a locking position and of being applied to a brake surface (B). The locking member can, when the rotary element rotates, be subjected in either direction to a drag force resulting from friction contact and thus displaced relative to the abutment (W) either into the running position or into the locking position, depending on the direction of turn. The abutment and locking member are two ring units fitted one inside the other and capable of rotating about the rotational axis (X) of the rotating element, the mutually engaging regions of the two ring units being at least one section of a circle which is eccentric relative to the rotational axis of the rotating element, and the locking member which co-operates with the brake surface (B) is provided around its periphery (21) with a braking region (21´) which is limited around the circumference.

Description

Thread delivery device

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

A thread delivery device of this type is known from US-A-3 642 219 and has been marketed by the applicant under the name SFS / SFT for over 20 years. The backstop, which is only hinted at in US-A-3 642 219, is arranged 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 over a relatively large diameter. In this thread delivery device SFS / SFT used in practice, the locking member is a disk made of plastic, which can be displaced between the running position and the braking position in a fork-like abutment anchored on the shaft, namely by means of that between an end face of the disk and the top cover of the engine caused by frictional drag force. The abutment has a concave slideway for the disk which rises in the return direction and stops formed on both ends of the slideway. In the running position, the disk at least largely disengages from the braking surface provided on the inner circumference of the storage drum. If the storage drum rewinds, the disc is displaced by the drag force along the slideway into a blocking position in which it is pressed against the braking surface. A return movement of the storage drum can have several causes. A thread scanner provided in the feed area of the thread delivery device is spring-loaded and can, after the storage drum has stopped, pull back the incoming thread and turn the storage drum back by means of the thread. Furthermore, the threads to be processed are mostly elastic, so that when the storage drum stops, the tension previously generated in the incoming thread passes over the storage drum want to turn the thread back. Finally, as a result of unfavorable circumstances and due to the motor being decelerated, a counter torque can arise which the storage drum wishes to turn back. The known backstop is complex in terms of production technology, susceptible to wear and tear and can cause undesirable vibrations especially when accelerating or at higher speeds, among other things because the disk acts on an extremely large diameter and with a very large lever arm. The known backstop requires an almost exactly vertical arrangement of the thread delivery device, which cannot be maintained in some applications. In addition, structurally complex measures are required to prevent the disc from burning on its end face which contacts the upper cover wall of the motor, because the disc contacts the cover wall at a large distance from the axis of rotation and therefore considerable friction is to be destroyed at high speed. .

The invention has for its object to provide a yarn delivery device of the type mentioned, in which a structurally simple, easy-to-assemble backstop is provided, which works reliably with little wear and tear and has a long service life and does not cause any vibrations.

The object is achieved according to the invention with the features contained in claim 1.

A noticeable influence at high speeds of the rotating element is eliminated due to the precisely adjustable drag force. This is of considerable advantage in particular in the case of modern yarn delivery devices, the rotational speed of which can be approximately 20% higher than in the case of yarn delivery devices previously used. The braking surface can be set to a diameter which can be significantly smaller than the inside diameter of an optionally provided storage drum. If the rotary element shows the tendency of a return movement, then that becomes Locking member rotated relative to the abutment in a smooth rotary motion by the drag force until its counter-braking area runs outwards or inwards against the braking surface thanks to the circle which is eccentric to the axis of rotation of the rotary element and blocks the reverse movement. The intervention into the blocking position takes place harmoniously and reliably, whereby a high braking power can be generated. It is particularly important that when the rotary element restarts in the correct direction of rotation, the locking member easily and forcibly releases from the braking surface and returns to the defined running position. The area of engagement between the locking member and the braking surface can be designed over a large area, so that there is no excitation for vibrations in the thread delivery device. The backstop works with little wear and reliably with a long service life. In general, it should be emphasized that the eccentricity and the diameter of the eccentric circle make it possible to predetermine and optimally design the characteristic curve with which the backstop takes effect or is released again.

According to claim 2, the backstop is carried out on an optimally small diameter, and in particular on a diameter independent of the size of the storage drum.

The towing force can be predetermined precisely by dimensioning the spring force. The pressure is expediently carried out against the action of gravity. The thread delivery device can therefore be used in any installation position without endangering the backstop. Furthermore, the area in which the locking member contacts the towing surface can be set relatively close to the axis of rotation of the rotating element, so that even at high rotational speeds and strong accelerations the risk of the locking member being burned is avoided, also by the ring shape, which have a relatively low specific surface pressure per unit area enables and still ensures sufficient towing power.

Although the locking element is automatically rotated into the locking position just required to prevent the return, without requiring a special stop for the locking position, it can be expedient, according to claim 4, to provide a stop for the locking member which ends ¬ locking position defined and excessive forces on the braking surface or the rotating element prevented.

The embodiment according to claim 5 is particularly expedient, in which the motor is fixedly arranged in the housing and the backstop is well encapsulated and separated from the working area of the storage drum, in which contamination and fluff are unavoidable. Since the locking member has no cooperation with the inside diameter of the storage drum, the diameter of the braking surface can be chosen small enough to exclude vibrations at high speeds and strong accelerations in modern thread delivery devices.

According to claim 6, the motor shaft is supported on the housing against a return via the rotating backstop.

Alternatively, according to claim 7, the backstop does not co-operate with the rotary movement of the rotating element, but only acts upon a backward movement in order to block the motor shaft via the braking surface attached, for example, to the motor shaft.

According to claim 8, the locking member cooperates with a brake ring which u.a. A high eremic effect due to the material.

Alternatively, a brake ring could be attached directly to or in the locking member (claim 9). A good backstop is also achieved with a braking surface that is only structured, for example knurled. This braking surface can be arranged in a metallic body, for example in the housing or in a housing insert.

The embodiment according to claim 11 is technically simple to manufacture. Molded plastic parts are distinguished by high dimensional accuracy, low weight and low wear. Since the locking member is pressed against the towing surface by precisely adjustable spring force, self-lubricating plastic qualities can be used, which ensure easy rotation of the locking member even over a long service life. The self-lubricating effect has no adverse effect on the braking effect with the braking surface, because a quick-acting forced intervention can be produced there anyway by the eccentric displacement movement of the locking member.

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

According to claim 13, the spring between the annular disc and the hub is arranged as an integral part of the backstop. The projections or the circumferential bead are an assembly aid for a pre-mintable structural unit, because the circular disk cannot fall off the ring flange under the force of the spring. In operation, the circular ring disk does not normally reach the projections or the peripheral bead.

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

1 is a side view, partly in section, of a yarn delivery device with a backstop, 2 the backstop in a section and on an enlarged scale, in the barrel division,

3 shows an axial top view of an abutment of the backstop,

FIG. 4 is 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 yarn delivery device F, preferably a yarn delivery device F for a knitting machine, has a stationary housing G on which a storage drum T is rotatably mounted on the underside and can be driven to rotate about an axis of rotation X by a motor M in a predetermined direction of rotation. The motor M can be switched on and off, specifically by means of signals which are generated by a scanning device D in a housing boom 1 as a function of the size of a thread supply (not shown) formed on the storage drum T. The thread (not shown) coming from a supply spool (not shown), which is fed to the storage drum T, is passed through stationary thread eyelets 2 through a thread brake 3 and, under the supervision of a sensing element 5, reaches the circumference of the storage drum T. An inclined feed element V pushes it each winding wound on the storage drum T in Fig. 1 downward, so that a thread supply is formed from several turns. The thread intended for consumption is drawn off at the top of the storage drum.

In the thread delivery device F, a backstop R is provided, namely between an upper cover wall 6 of the housing G and the upper end of a motor shaft H. In the embodiment of FIG. 1, the backstop R contains a non-rotatably connected to the motor shaft H. Abutment W and a re Locking member S, which is mounted in a relatively rotatable manner and is loaded upwards by a weak screw spring 4 and serves to cooperate with a braking surface B of an insert 7 provided in the top wall 6, namely by a return or a return movement of the storage drum T. or to prevent the motor shaft H after a standstill.

2, the abutment W is an annular body AI, consisting of a hub 8, which is non-rotatably fitted with a non-circular inner bore 9 onto the matching end 10 of the motor shaft H, a radial flange 11, which has a spring seat 12 defined, and an axial ring flange 14 with a cylindrical outer peripheral surface 15, the axis XI of which is eccentric with respect to the axis of rotation X of the motor shaft H. Furthermore, a cutout 17 which is delimited in the circumferential direction is formed in the annular flange 14 and (FIG. 3) defines two stops 18 and 18 'spaced apart in the circumferential direction. A circumferential bead 16 is formed in the end region of the ring flange 14.

The locking member S, which is rotatably mounted on the abutment W relative to this, is also an annular body A2, specifically an annular disc 19 with an inner bore 20 and a cylindrical outer circumference 21, which is intended for cooperation with the braking surface B. In the running position of the backstop R shown, the central axis of the peripheral surface 21 at least approximately coincides with the axis of rotation X. The central axis of the inner bore 20, however, coincides with the axis XI, which is eccentric to the axis of rotation X. In one end face of the annular disk 19, a spring receiving groove 13 for the helical spring 4 is formed which is concentric with the peripheral surface 21 and which is supported with its other end in the spring seat 12 of the flange 11 and the annular disk 19 with at least part 22 of its other Presses end face against a trailing surface 23 fixed to the housing. In the inner bore 20 of the annular disk 19, a nose 26 protrudes inward, which defines stops 27 and 27 'according to FIG Interact stops 18 and 18 'to set a barrel position and a locked position. The 3remsflache B and the drag surface 23 are included in the insert 7, which is fixed in the top wall 6. It is conceivable to arrange the towing surface 23 and the braking surface 21 directly in the top wall 6.

In this embodiment, the braking surface B is provided on a brake ring 24 made of a friction-active material, such as rubber, elastomer or another plastic, which is fixed in a socket 25 of the insert 7. In the running position shown in FIG. 2, in which the backstop R does not influence the normal rotation of the motor shaft H, a radial play Y is provided between the peripheral surface 21 and the braking surface B.

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

In the running position, the locking member S according to FIG. 4 is seated in 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. The nose 26 abuts the stop 18 'against the stop 18'. The circumferential surface 21 is then essentially concentric with the axis of rotation X and faces the braking surface B (FIG. 2) with the radial play Y. The motor shaft H driven counterclockwise in FIGS. 3 and 4 takes the locking member S with it via the abutment W without the braking surface B coming into contact. By the pressure of the spring 8, the locking member S against the drag surface 23rd pressed so that a permanent drag force acts in the locking member S by frictional contact, which holds it clockwise with the stop 27 'on the stop 18'.

After the motor shaft H has come to a standstill, in the event of a return (rotational movement of the motor shaft H in the clockwise direction in FIGS. 3 and 4), a contact force with the trailing surface 23 on the locking member S generates a counterclockwise tractive force. This drag force rotates the locking member S relative to the abutment W on the ring flange 14, the outer circumferential surface 21 of the locking member being displaced outward in a circumferentially limited counter-braking area and running against the braking surface B. A further return movement of the motor shaft H is prevented in this way. If necessary, 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 again in the desired direction, i.e. 3 and 4 counterclockwise, then the towing force on the towing surface 23 retains the locking member S, the peripheral surface 21 is released from the braking surface B and is centered again with respect to the axis of rotation X.

A kinematic reversal is conceivable in such a way that the ring body A2 is rotatably mounted on the top wall 6 or in the insert 7, whereas the ring body AI rotatably comprises the motor shaft H or its end 10 (which then has a cylindrical outer circumference), expediently again with a Radial game. The end surface 23 'of the motor shaft H, which cooperates with the end surface 22' of the annular body AI under the pressure of the spring 4, then serves as the drag surface. The braking surface B can then be provided either on the outer circumference of the motor shaft H or in the inner bore 9 of the ring body AI. In this case, the ring body A2 forms the abutment W and the ring body AI the locking member S. 5, the embodiment shown in FIGS. 2, 3 and 4 is shown schematically, in which the locking member S is rotatably mounted on the outside of the abutment W and cooperates with the braking surface B.

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

In the embodiment according to FIG. 7, which corresponds schematically to the functional principle of FIG. 5, a braking surface area 21 ′, which is limited in the circumferential direction and is intended to cooperate with the braking surface B, is formed on the outer circumference 21 of the locking member S.

Similarly, in the embodiment of FIG. 8, which corresponds to the functional principle of FIG. 6, in the inner bore 9 of the locking member, a circumferentially limited, inwardly projecting braking surface region 9 'is formed, which is used for cooperation with the braking surface B, in present case on the motor shaft H, is determined. The abutment W is an annular body with a non-circular outer circumference, which simplifies the determination of the abutment. 7 and 8, the braking surface area 21 'or 9' can also have a curvature whose center of curvature does not coincide with the center of the cylinder surface 21 or 9, i.e. the braking surface area 21 'or 9' could be curved more or less in order to achieve a special braking effect.

The backstop shown in FIG. 1 could also be arranged below the motor M. Conveniently, however, the backstop R should be encapsulated and away from the sphere of influence of Soiling or lint, which are unavoidable when processing thread material, must be separated. The diameter at which the locking member interacts with the braking surface B is advantageously substantially smaller than the diameter "of the storage drum T or its inner diameter. The size of the contact area between the locking member and the drag surface 23 or 23 'should be chosen such that Under the pressure of the spring 8, a drag force that is sufficient for the function is ensured, but overheating or burning of the locking member is excluded.

Claims

claims

1. Thread delivery device, in particular for knitting machines, with a stationary housing and a rotary element which can be driven in one direction of rotation by means of a motor which can be switched on and off and is mounted on the housing for winding a thread into a thread supply consisting of a plurality of turns on a storage surface, depending on the consumption of the thread Head can be pulled off, with a movement of the sensor device sensing the limit of the thread supply which varies in the pulling direction, with which signals for switching the motor on and off can be generated, and with a mechanical backstop which prevents and prevents a return movement of the rotating element relative to an abutment between a running position defined by a stop and a blocking position, which includes a blocking element which can be brought into engagement in the blocking position on a braking surface and which, when the rotary element rotates in each direction of rotation, has an ore by frictional contact eugte towing force and by the towing force depending on the direction of rotation relative to the abutment either in the running position or in the blocking position, ge ge characterized in that the abutment (W) and the locking member (S) two nested around the axis of rotation (X ) of the rotary element are rotatable ring bodies, the mutual engagement area of which is at least a portion of a circle eccentric to the axis of rotation of the rotary element, and that the locking member (S) cooperating with the braking surface (B) has a circumferential limit on its circumference (21) Has braking area (21 ').

2. Thread delivery device according to claim 1, characterized in that the diameter of the braking surface (B) is significantly smaller than the inner diameter of the storage drum (T).

3. Thread delivery device according to claim 1, characterized in that an end face of the locking member (S) defining Ring body (AI or A2) can be pressed by a spring force (4) approximately parallel to the axis of rotation (X) of the rotating element against a trailing surface (23, 23 ') fixed to the housing or to a rotating element.

4. Thread delivery device according to claim 1, characterized in that in addition to the stop defining the running position a locking position, preferably an end locking position, defining stop is provided for the relative rotational movement between the ring bodies.

5. Thread delivery device according to at least one of claims 1 to 4, characterized in that the rotary element is a rotatably fixed storage drum (T) carrying motor shaft (H) of the housing (G) arranged motor (M), and that the return lock (R) is arranged between a housing wall (6) facing away from the storage drum (T) and the motor (M), preferably on a motor shaft extension (10).

6. Thread delivery device according to claim 5, characterized in that the abutment (W) defining ring body (AI) is arranged rotatably on the motor shaft (H), that the locking member (S) defining ring body (A2) outside on the Wi ¬ the bearing ring body is mounted, and that the braking surface (B) outside the locking member (S) and the drag surface (23) ei¬ ner end face of the locking member (S) are arranged facing in the housing wall (6), preferably in one insert (7) held in the housing wall (6).

7. Thread delivery device according to claim 5, characterized in that the abutment (W) defining ring body (AI) rotatably in the housing wall (6), preferably in a bearing of the housing wall (6), is held that the locking member ( S) defining ring body (A2) is mounted inside the abutment ring body, and that the braking surface (B) within the locking member (S) and the drag surface (23 ') of an end face of the blocking member (S) are each arranged on the motor shaft (H), preferably in an insert held on the motor shaft (H).

8. Thread delivery device according to claim 6 or 7, characterized gekenn¬ characterized in that the braking surface (B) of a locking member (S) or the locking member (S) encompassed brake ring (24), preferably in the running position with a radial

Game (Y) made of a friction material, for example rubber or elastomer.

9. Thread delivery device according to at least one of claims 1 to 7, characterized in that a brake ring (24) made of frictionally active material is arranged outside on or inside in the locking member (S).

10. Thread delivery device according to at least one of claims 1 to 7, characterized in that the braking surface (24, 25) is structured, for example knurled.

11. Thread delivery device according to at least one of claims 1 to 10, characterized in that the two ring bodies

(AI, A2) are molded plastic parts.

12. Thread delivery device according to claims 5 and 6, characterized ge indicates that the abutment ring body is a non-rotatably on the motor shaft (H), preferably by means of a non-circular inner bore (9), attachable hub (8) having an axial Ring flange (14) with cylindrical outer periphery (15) eccentric to the axis of rotation (X) of the motor shaft (H) and a radial flange (11) defining a spring seat (12), and that in the outer periphery (15 ) of the ring flange (14) are formed in the circumferential direction spaced stops that step back or protrude outwards from the outer circumference, and that the locking member ring body is a circular ring disk (19) with a cylindrical outer circumference (21) and one with respect to the center of the outer circumference (21) is an eccentric inner bore (20), the inner diameter of which corresponds to the outer diameter of the ring flange (14) of the hub (8), and that in the inner bore (20) an inwardly protruding nose (26 ) or a diameter extension limited in the circumferential direction is provided.

13. Thread delivery device according to claim 12, characterized gekennzeich¬ net that in the flange (11) facing the end face of the annular disc (19) to the axis of rotation (X) of the motor shaft (H) concentric spring receiving groove (13) for a screw spring (4th ) is provided, the other end of which is supported on the spring seat (12) of the flange (11) of the hub (8), and that in the region of the free end of the ring flange (14) slightly projecting beyond the outer diameter of the ring flange jumps or a peripheral bead (16) are formed.