EP0964826A1

EP0964826A1 - Thread detector

Info

Publication number: EP0964826A1
Application number: EP98965853A
Authority: EP
Inventors: Patrik Jonas Magnusson; Staffan HAGSTRÖM
Original assignee: Iropa AG; Iro Patent AG
Current assignee: Iropa AG
Priority date: 1997-12-17
Filing date: 1998-12-17
Publication date: 1999-12-22
Anticipated expiration: 2018-12-17
Also published as: DE59807558D1; DE19756242A1; US6357692B1; CN1109647C; EP0964826B1; WO1999031001A1; KR20000071171A; KR100353240B1; CN1249727A

Abstract

The invention relates to a thread detector (F), especially for a thread sensor in a thread feeding device, comprising a detector foot (A) with an essentially flat rest (B) which can be brought into contact with a thread (Y). The detector foot (A) has an uninterruptable surface (P) at least in the area of the rest (B) of said foot in order to gently handle the thread when swept and above all to prevent contaminants from attaching inside the detector foot (A).

Description

Thread sensor

The invention relates to a thread sensor specified in the preamble of claim 1.

In thread processing technology, a thread mechanically acting thread sensor is used, e.g. in thread delivery devices for scanning thread windings that move mainly transversely to the thread axis. A design has prevailed in which the thread sensor is bent from a wire section so that its thread base forms an approximately U-shaped tongue, which is aligned with its longitudinal axis approximately transversely to the thread axis, and on the underside of which the thread to be scanned sweeps along.

From the operating and maintenance instructions IWF 9007, 9107, 9207 from IRO AB with the reference numbers 07-8930-0812-01 / 9647, p. 10, 44, 50, and 51, a thread sensor is known, which is designed as a two-legged wire bracket and is pivotally held with an axis mounted in the housing of a thread delivery device such that its downwardly bent thread foot rests on the thread turns of a thread supply moving forward on the storage drum of the thread delivery device and can be deflected by the thread turns from a basic position in order for a control or monitoring device Emit signals. The U-shaped, two-legged thread foot points in the direction of movement of the thread turns and is inclined downwards. During the operation of the thread delivery device, impurities and, above all, fluff collect in the U-bend of the thread foot until a fluff tail hanging from the sensor foot is formed. This lint accumulation in the U-bend and the fluff tail can lead not only to malfunctions in the thread scanning, but also to faults downstream of the thread sensor and to tissue damage if such an accumulation is torn loose and moves with the thread. The danger of a disturbance due to such accumulations is particularly great with thread sensors which are permanently in contact with thread turns in the trouble-free operation, for example with a thread break sensor which detects the first Thread turns in the thread supply are monitored for presence in a thread delivery device.

The invention has for its object to provide a thread sensor of the type mentioned, which is characterized by increased operational reliability.

The stated object is achieved with the features of patent claim 1.

The uninterrupted surface, at least in the area of the support of the sensor foot, precludes the accumulation of impurities and lint in the sensor foot, and thus also prevents the formation of a dreaded fluff tail. In addition, with the uninterrupted area in the area of the support, the thread is very gently stressed by the contact pressure of the thread sensor, which is favorable for sensitive thread qualities and / or high thread speeds. Overall, the operational reliability of the thread sensor is improved in this way, because disturbances due to the accumulation of contaminants in the sensor base are avoided and the mechanical load on the thread to be scanned is reduced (reduced risk of thread breakage).

According to claim 2, the uninterrupted surface is extended to at least the beginning of the shaft of the feeler foot, in order not to give the fluff which occurs inevitably during thread processing any possibilities for getting caught.

According to claim 3, the contact pressure of the feeler foot is distributed on the thread. An approximately rectilinear generatrix can be concave, actually straight or convex, possibly depending on the geometrical shape in which the thread to be scanned is located during the scanning.

According to claim 4, the uninterrupted surface should be convexly curved or composed of several surface sections in order to pass to provide the thread with a low and constant resistance, and on the other hand to be able to properly deflect the feeler foot through the thread.

In the tip section of the feeler foot, the surface should have a part essentially parallel to the storage drum, the size of which is sufficient to cover two adjacent turns at the same time, in particular in the case of thread separation.

According to claim 6, the uninterrupted surface should be rounded or beveled in the edge region, in order, if it forms the support at the same time, to exclude any edges or cutting dangerous for the thread.

According to claim 7, the sensor base is a molded part, preferably made of metal or plastic, in which the uninterrupted surface is integrated in one piece. This embodiment is advantageous in terms of manufacturing technology. Since the sensor foot should only work with its surface, it can even be hollow to save weight.

According to claim 8, the shaft is formed by two spaced legs, which are transferred with their outer contours parallel to one another or even convergingly into contact with the sensor base. This is particularly important when using the feeler foot in a thread delivery device, because when threading or due to other influences, the thread can sometimes be lifted temporarily and then run against the shaft. The shaft should then automatically let the thread slide under its tension alone under its thread tension, so that the thread cannot get caught on the feeler foot or on the shaft.

According to claim 9, the sensor base is alternatively formed from a wire section, for example: curved, the space between the legs being filled by an insert (hollow or solid). The insert occupies the space, so to speak, so that contaminants and fluff can no longer be fixed there. According to claim 10, the sensor foot is made of wire and is provided with a shoe-like coating, which also prevents impurities and fluff from getting stuck in the space between the legs and also forms the support.

According to claim 11, the space between the legs of the sensor foot bent from wire is covered by a membrane-like flat element which either withdraws behind the support or forms the support. Again, the setting of impurities and fluff is counteracted by the uninterrupted surface between the legs.

According to claim 12, the feeler foot is a skid-like flat element which has the support and the uninterrupted surface and is freely cantilevered on the shaft. This is a particularly light-weight and structurally simple embodiment in which the setting of impurities and lint is excluded.

Should a cavity remain by covering the space between the legs of the wire foot bent with respect to the thread in the sensor foot, then this cavity could be filled with a filling according to claim 13 in order to prevent the ingress of contaminants or fluff. This filling could be, for example, foam or other material (e.g. potting compound) that has no other function than filling the cavity.

A thread sensor of conventional construction and embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:

1 shows a thread sensor according to the prior art in a side view and a plan view,

2-6 different embodiments of thread sensors according to the invention, 7 + 8 a cross section and a top view of a further embodiment of a sensor foot of a thread sensor,

9 is a perspective bottom view of a further embodiment of a

Feeler foot, and

10 is a perspective side view, partly in section, of a sensor device with a plurality of thread sensors in a thread delivery device.

In Fig. 1 (in two views) a thread sensor F of conventional training in thread scanning is shown. The thread sensor is bent as a two-legged bracket made of a wire material 1 with legs 2 and 3, which have their point of reversal in a bend 4 and form the sensor base A bent over a shaft 6 relative to the sensor arm F. With the undersides of the legs 2, 3, a support B is defined in the feeler foot A, along which the thread Y slides when scanning. The thread sensor F is raised in the direction of the double arrow over the support B in order to generate, for example, a signal which represents the presence of the thread Y (possibly a plurality of thread windings) under the sensor foot A. In the lower representation of FIG. 1 it can be seen that there is an intermediate space 5 between the legs 2, 3 in the area of the sensor foot A, which gap narrows towards the bend 4 in a gore-shaped manner. During the thread processing, lint is inevitable, which has the unpleasant tendency to collect in any suitable place and form tufts of fluff. Experience has shown that the intermediate space 5 fills relatively quickly with impurities and fluff, which form a tuft of fluff L. If additional fluff is fed in, a fluff tail L 'can even occur, which is dragged along in the direction of movement of the thread or threads Y. The fluff tuft L or the fluff tail L 'can lead to malfunctions and considerably impair the work of the thread sensor. In addition, the feeler foot A with the support B lies essentially only linearly on the thread Y, which may result in a locally high load for the thread. In FIG. 2, in the case of a thread sensor according to the invention made of wire material with legs 2, 3 in sensor foot A, a flat element 7 is used in the area of support B, which has an uninterrupted surface P. The element 7 can even, as shown at 8, be extended from the sensor foot A to the shaft 6. The feeler foot A optionally applies the surface P and the two legs 2, 3 forming the support B to the thread. In the intermediate space 5, fluff can no longer get caught or fluff can only separate to a non-dangerous extent.

In Fig. 3, a flat element T is attached to the underside of the sensor foot A, which is optionally extended into the shaft 6 (at 8) and forms both the support B and the uninterrupted surface P with which the sensor foot A the thread acted upon. The edges of the element 7 'are expediently drawn up in a rounded manner (indicated at 9). Lint can no longer collect in the intermediate space 5, or only to a non-dangerous extent.

In Fig. 4, a shoe-like cover 7 "is drawn over the feeler foot A, which optionally extends to the shaft 6 and covers the intermediate space 5 both from below and from above. The support B and the surface P with which the thread acts is formed by the coating 7 ". The cavity which arises in the area of the intermediate space 5 and in the interior of the cover 7 "can contain a filling 10, for example foam or another material. It would also be conceivable to close the cover 7" on the shaft.

5, a membrane-like, flat element 7 "'is inserted in the feeler foot A between the legs 2, 3, which forms the surface P and covers the intermediate space 5, but is higher than the support B. As a result, it becomes contaminants and fluff impossible to collect and cause interference.

A similar flat element T is provided in FIG. 6, as is used in FIG. 3 to cover the intermediate space 5. 6 forms the flat element 7 ', which can have the shape of a runner, directly the feeler foot A. For this purpose, the element 7' is attached to the legs 2, 3, which form the shaft 6. The element T carries the surface P and forms the support B with which the feeler foot A acts on the thread. The element 7 'can have a rounded raised edge 9 and can be extended to the shaft 6 at 8.

In Fig. 7, an insert 11 is inserted into the feeler foot A between the legs 2, 3, which fills the intermediate space 5 and optionally extends to the support B or forms it. The insert 11 defines an uninterrupted area P, which prevents the accumulation of fluff and impurities in the intermediate space 5. The insert is optionally pulled up to the shaft 6 (as shown) and, for example, conforms to the curvature of the legs 2, 3 (in the case of round wire material) with an edge groove. The insert, which is made of plastic, for example, could also be glued in or fixed in some other way.

2 to 8, the surface P can be approximately parallel to the main plane of the sensor base A and even. Alternatively, however, a convex downward curvature is also possible, namely in the longitudinal section and / or in the cross section. The elements 7, 7 ', 7 ", 7'" could be made of plastic or sheet metal.

In Fig. 9, the sensor base A with its legs 2 ', 3' is a solid or hollow molded part made of plastic or metal, which is either integrally connected to the sensor arm F, not shown, or is attached to this. The uninterrupted surface P on the underside of the sensor foot A is formed - in the direction of movement of the thread Y - with a concave curvature or formed from individual, butt-jointed surface sections 12. At the tip of the feeler foot A there should be a surface section of a size that is essentially parallel to the storage drum surface and approximately flat, which ensures that two adjacent thread turns are covered even when the thread is separated. Furthermore, the surface P can be approximately flat in the direction of the longitudinal axis of the thread, or can be concave or convex curved. The outer edge area of the surface P is expediently Usually rounded or beveled (at 15 or 15 '). The area P is extended to the start of the shaft 16 and ends there with a transverse edge 14 and a transverse wall 13. The top of the sensor foot also has an uninterrupted surface P '. The legs 2 ', 3' either run parallel and at a distance from one another or even converge towards the feeler foot 8. This construction is also provided in the embodiments of FIGS. 2 to 8, with regard to the use of the sensor arm in a thread delivery device, in which (for example when threading) the thread first comes to rest laterally on one of the legs and then under the the tension in it must be pulled automatically to below the support B without being able to get caught on the sensor arm or sensor foot. For example, light metal is used to manufacture the sensor base A.

FIG. 9 shows a winding element 21 adjacent to a stationary storage drum T from a thread delivery device D, on which the thread Y is wound in adjacent turns and, when used in FIG. 10, is pulled off to the right overhead of the storage drum T. The thread delivery device has three thread sensors S1, S2, S3 in this area, each with a sensor arm F and a sensor foot A, for example according to FIG. 9. The sensor feet A grip from the outside of a sensor housing 20 towards the storage drum T, which in this area is formed with a longitudinal recess 22 which the thread Y spans. The first sensor S1 is, for example, a thread break sensor that monitors whether the first turns of the thread supply are properly present or not. As long as there are turns, the sensor arm F remains in a raised position. If these first turns fail to appear, then it will sink, from which a signal for a fault is generated (thread break). The second sensor S2 is a minimum sensor which monitors the minimum permissible size of the thread supply on the storage drum T and, in the absence of the thread in this area, generates a signal with which the drive for the winding element 21 is switched on or accelerated in order to supplement the thread supply . The third sensor S3 is a maximum sensor which monitors the maximum permissible size of the thread supply and, in the presence of thread Y in this area, a signal for switching off or decelerating the drive of the Winding element generated. The turns of the thread Y move from left to right in FIG. 10, for example with a thread separation.

The three sensor arms F are pivotally mounted on a common axis 18 and are loaded by a spring arrangement C in the direction of a defined basic position (lowered). Each sensor arm F consists of a sensor arm part 17 which carries a stop 19 for cooperation with the spring arrangement C and a jack 16. For example, a leg 2 ', 3' of the sensor foot A is inserted into the socket 16. Furthermore, scanning devices T are provided for each sensor arm F, which, e.g. Non-contact and opto-electronic, generate signals depending on whether the assigned sensor arm F is in the basic position or has been displaced from it. In the basic position, each sensor foot A with its support B or surface P, which is not highlighted in FIG. 10, is at a distance from the bottom of the recess 22. The distance is dimensioned such that the thread Y, when passing under the sensor foot, extends the sensor foot upward displaced the basic position. In the sensor device according to FIG. 10, three sensors are combined with one another in a small installation space. However, more than three sensors or fewer could also be provided. The sensor feet A are identical (rational production); In order to adapt to the respective installation condition, the leg 2 ', 3' not inserted into a socket 16 is shortened to the necessary length.

Claims

claims

1. Thread sensor, in particular for a thread sensor in a thread delivery device, with a sensor foot (A) which forms a substantially flat support (B) which can be brought into contact with a thread (Y), characterized in that the sensor foot (A) at least has an uninterrupted surface (P) in the area of its support (B).

2. Thread sensor according to claim 1, characterized in that the feeler foot (A) subsequent to the support (B) has a shaft (6) which bends relative to the main plane of the support (B), and that the surface (P) of the support ( B) can be extended into the shaft (6).

3. Thread sensor according to claim 1, characterized in that the surface (P) has an approximately parallel to the thread axis approximately rectilinear generatrix.

4. Thread sensor according to claim 3, characterized in that the surface (P) in the direction perpendicular to the generating line and with respect to the thread is convexly curved or composed of a plurality of raised surface sections (12).

5. Thread sensor according to claim 1, characterized in that the support (B) on the feeler tip has a substantially parallel to the direction of movement of the thread (4) and approximately flat part in a size with which at least two adjacent threads or thread turns can be covered .

6. Thread sensor according to claim 1, characterized in that the closed surface (P) along its outer edge is rounded or beveled (at 15).

7. Thread sensor according to claim 1, characterized in that the sensor base (A) is a solid or hollow molded part, preferably made of metal or plastic, in which the surface (P) is integrated in one piece.

8. Thread sensor according to at least one of the preceding claims, characterized in that two spaced legs (2, 3; 2 ', 3') are provided in the shaft (6) and in the sensor foot (A), the outer contours of the shaft (6) to each other are converged into the sensor base (A) parallel or even in the direction of the course to the support (B).

9 sensor base according to claim 1, characterized in that the sensor base (A) is formed in two legs with an intermediate space (5) between the legs (2, 3) from a wire section (1), and that at least in the region of the support (B ) a hollow or solid insert (11) fills the intermediate space (5), the surface (P) and optionally the support (B) being arranged on the insert (11).

10. Thread sensor according to claim 1, characterized in that the sensor foot (A) is formed with two legs with an intermediate space (5) between the legs (2, 3) from a wire section (1), and that in the region of the support (B) shoe-like cover (7 ") is attached to the feeler foot (A) which forms the support (B) and the surface (P).

11. Thread sensor according to claim 1, characterized in that the sensor base (A) is formed with two legs with an intermediate space (5) between the legs (2, 3), and that the intermediate space (5) by at least one membrane-like flat element (7, 7 ', 7' ") is covered, which forms the surface (P) and is either arranged on the legs (2, 3) or inserted between the legs (2, 3).

12. Thread sensor according to claim 1, characterized in that the sensor foot (A) is a skid-like flat element (7 ') which has the surface (P) and the support (B) and on the shaft (6), preferably on the Legs (2, 3) is freely cantilevered.

13. Thread sensor according to at least one of the preceding claims, characterized in that a cavity in the sensor base (A) contains a filling (10).