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Title:
DEVICE AND METHOD FOR PERFORMING RESISTANCE TESTS ON KNITTED ARTICLES, SUCH AS PANTY-HOSES AND SOCKS
Document Type and Number:
WIPO Patent Application WO/2013/124214
Kind Code:
A1
Abstract:
The device comprises a column element (11) onto which the knitted article to be tested (M) is inserted. The column element comprises in turn two portions (11A, 11B) movable with respect to each other. The device also provides a fastening member (13) for fastening the knitted article (M) on one of said two portions (HA) of the column element (11). Sensors (37) associated with the other portion (11B; 11A) of the column element are arranged to detect a stress on the knitted article. A breaking member (43; 63, 65) is also provided to apply a breaking action to the knitted article.

Inventors:
GRASSI NERINO (IT)
GIUDICI DAVIDE (IT)
NOBIS MATTEO (IT)
ARDELEAN OANA (IT)
Application Number:
PCT/EP2013/053044
Publication Date:
August 29, 2013
Filing Date:
February 15, 2013
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
GOLDEN LADY CO SPA (IT)
International Classes:
D06H3/16; D06C5/00; G01N3/08
Foreign References:
US2369661A1945-02-20
US4136557A1979-01-30
US2066311A1937-01-05
GB301324A1930-01-02
Other References:
None
Attorney, Agent or Firm:
MANNUCCI, Michele et al. (Via della Scala 4, Firenze, IT)
Download PDF:
Claims:
Claims

1. A device for performing resistance tests on knitted articles, in particular socks or panty-hoses, comprising: a column element (11), onto which the knitted article (M) to be tested is inserted, said column element (11) comprising two portions (11A, 1 IB) movable with respect to each other; a fastening member (13) for fastening the knitted article (M) on one (11 A) of said two portions (1 IB; 11 A) of the column element (11); at least one sensor (37) associated with the other (1 IB) of said two portions (1 IB; 11 A), arranged to detect a load on the knitted article (M); at least one breaking member (43; 63, 65) to apply a breaking action to the knitted article.

2. Device as claimed in claim 1, wherein a first (11 A) of said two portions (11 A, 11B), movable with respect to each other, of said column element (11) is carried by a base (3) and a second (11B) of said two portions (11 A, 11B) is movable telescopically with respect to the first portion (11 A) parallel to an axis (A- A) of the column element (11), said movable second portion (11B) having a front surface (25) transverse with respect to the axis of the column element (11).

3. Device as claimed in claims 1 or 2, wherein said at least one breaking member (43; 63, 65) comprises a cutting or perforating member (43).

4. Device as claimed in claim 3, wherein said cutting or perforating member (43) is housed inside said column element (11) and is associated with an actuator (45) controlling the extraction of the cutting or perforating member (43) from the column element (11) to act on the knitted article (M).

5. Device as claimed in claims 2 and 4, wherein said cutting or perforating member (43) is arranged and controlled so as to be extracted from said front surface (25) of the movable second portion (1 IB) of said column element (11).

6. Device as claimed in claim 5, wherein said cutting or perforating member (43) is carried by the movable second portion (11B) of the column element (11) and moves therewith, with respect to the fixed first portion (11 A) of the column element (11).

7. Device as claimed at least in claim 2, wherein said at least one sensor (37) is carried by the movable second portion (1 IB) of the column element (11) and is designed to detect a force applied thereon by a portion of knitted article (M) frontally stretched on the movable second portion (1 IB) of said column element (11).

8. Device as claimed in one or more of the previous claims, comprising two sensors (37) arranged to detect a load on the knitted article (M).

9. Device as claimed in claim 8, wherein said two sensors (37) are symmetrically arranged with respect to an axis (A- A) of said column element (11).

10. Device as claimed at least in claim 2, wherein said at least one sensor (37) is housed in said movable portion (11B) of the column element (11) and cooperates with a load transfer unit (39) which emerges on front surface (25) of the movable portion (11B) of the column element (11), said load transfer unit (39) transferring on the sensor (37) the load directly or indirectly applied thereon by the knitted article (M) when said knitted article (M) is stressed due to the reciprocal movement of the two portions (11A, 1 IB) of the column element (11).

11. Device as claimed in one or more of the previous claims, wherein said breaking member (43; 63, 65) comprises a component (63, 65) which can be connected to one (1 IB) of said two portions (11 A, 1 IB) of the column element (1 1), said component (63, 65) being arranged and designed to apply a stress on the knitted article (M) during the test.

12. Device as claimed in claims 2 and 11, wherein said component (63, 65) is connectable to the front surface (25) of the movable second portion (11B) of the column element (11).

13. Device as claimed in claim 12, comprising a reversible coupling between said component (63, 65) and the front surface (25) of the movable second portion (1 IB) of the column element (11).

14. Device as claimed in claim 13, wherein the movable second portion (11B) of the column element (11) and said component (63, 65) have reciprocal guiding means (61, 53, 55).

15. Device as claimed in claim 14, wherein said component (63, 65) has pins (61) which are integral with said component (63, 65), which can be constrained in seats (51) provided in the movable second portion (11B) of the column element (11), and which are open on the front surface (25) of said movable second portion (1 IB) of the column element (11).

16. Device as claimed in claim 15, comprising closing members (51) for closing said seats (53) when the component (63, 65) is not applied to the column element (11).

17. Device as claimed in one or more of claims 11 to 16, wherein said component (63, 65) is designed and arranged to transmit on said at least one sensor (37) a load generated by the thrust of the knitted article (M) stretched on the column element (11).

18. Device as claimed in claims 10 and 13, wherein said component (63, 65) is connectable to the front surface (25) of the movable second portion (11B) of the column element (11) so as to cooperate with said load transfer unit (39).

19. Device as claimed in one or more of claims 11 to 18, wherein said component (63, 65) comprises a base (63), which is connectable with the column element (11), and at least one shaped protuberance (65) that can be applied to said base (63), said shaped protuberance interacting with the knitted article (M).

20. Device as claimed in claim 19, comprising a plurality of interchangeable shaped protuberances (65).

21. Device as claimed in one or more of the previous claims, comprising a control unit (4) programmed to perform testing cycles on knitted articles.

22. A testing method for testing the resistance of a knitted article, in particular a panty-hose or a sock, by means of a device as claimed in one or more of the previous claims, comprising the steps of:

- loading and fixing a knitted article (M) on said column element (11);

- stretching the knitted article (M) on the column element (11), spacing out the two portions (11 A, 1 IB) of said column element (11);

- cutting or perforating the knitted article (M) stretched on said column element

(i i);

- detecting the run resistance of said knitted article (M).

23. Method as claimed in claim 22, comprising the further steps of:

- increasing the elongation stress of said knitted article (M) after cutting or perforating until a run is formed;

- detecting the run resistance of said knitted article (M) based at least upon the stress applied on the knitted article (M) when the run is forming.

24. A testing method for testing the resistance of a knitted article, in particular a panty-hose or a sock, by means of a device as claimed in one or more of the previous claims, comprising the steps of:

loading and fixing a knitted article (M) on said column element (11);

stretching the knitted article (M) on the column element (11), spacing out the two portions (11 A, 1 IB) of said column element (11);

gradually increasing the stress of the knitted article (M) until breaking thereof, detecting the applied stress;

detecting the breakage resistance of said knitted article (M) based upon the stress under which the breakage occurs.

Description:
"DEVICE AND METHOD FOR PERFORMING RESISTANCE TESTS ON KNITTED ARTICLES, SUCH AS PANTY-HOSES AND SOCKS"

Description

Technical field

The present invention relates to the field of knitted articles manufacturing, on circular or straight knitting machines.

State of the art

In the field of knitted articles production, manufacturing of women's pantyhose and socks is very important. These knitted articles are manufactured with mainly synthetic and extremely fine yarns. One of the critical aspects of this type of manufactured article is its resistance to breakage and running.

The type of fiber used in manufacture is important for purposes of mechanical resistance of the final product. The search for new fibers includes the need to check their suitability for the manufacture of knitted articles, particularly in terms of being run-proof, i.e. resistance to running, and also mechanical resistance to breakage.

There is therefore a need for a device which performs resistance tests on knitted articles, in particular, for example (but not exclusively), socks, panty-hose, tights and similar.

Summary of the invention

Basically, in order to conduct resistance tests on a knitted article, for example and in particular, a tubular article like a sock or one comprising portions of tubular fabric, such as panty-hose or tights, a device is provided comprising a column element onto which the knitted article to be tested is inserted, said column element comprising two portions movable with respect to each other; a fastening member for fastening the knitted article on one of said two portions of the column element; at least one sensor associated with the other of said two portions, arranged to detect a stress on the knitted article; at least one breaking member to apply a breaking action on the knitted article.

In some embodiments, the device may be produced to perform only one type of resistance test, for example a running resistance test. For this purpose, a perforating or cutting member may be provided. In other embodiments, this perforating or cutting member may be used to produce an interruption in the knit of the fabric from which a run may start.

To conduct a running resistance test, the device may comprise a perforating or cutting member movable between a retracted position inside the column element and an extracted position, in which it cuts or perforates the knitted article on a portion thereof which is stretched in front of the perforating or cutting member. For example, the perforating or cutting member may be extractable from a hole or slot which is positioned frontally on the column element, so as to cut into, perforate or cut a portion of knitted fabric stretched on the front end of the column element. A run starts from the perforating or cutting point, which may form immediately upon cutting or perforating, or subsequently, when the knitted article is subjected to increased elongation or traction.

In other embodiments, the device may be provided with a breaking member which performs a breaking resistance test on the fabric. In this case, the breaking member comprises, for example, a protuberance of an appropriate shape and size against which the knitted article is stretched. In this case as well, the protuberance may be carried frontally by the column element, so that the test may be conducted by extending the column element telescopically until it causes breakage of the knitted article on the protuberance.

In advantageous embodiments, the protuberances may be interchangeable. Protuberances of different shape and/or size may be used to conduct different types of tests or tests on other types of knitted fabrics, or on different parts of a knitted article.

Advantageously, in some embodiments, the device is provided to be able to perform both running resistance tests and breakage resistance tests. For this purpose, the two different breaking members may be designed to be mounted in a selective and interchangeable manner. For example, the end of the column element may be shaped to receive, respectively, one or the other of the two respectively cutting or perforating members, or the breaking member.

In other preferred embodiments, the device has a cutting or perforating member which always remains on the column element and which may be used to perform running resistance tests, or may remain inside a housing or seat of the column element. A second breaking member, to perform breaking tests, may be provided to be mounted on the column element only when required. In some embodiments, the column element is telescopic and has at least two portions movable parallel to the axis of the column element to extend or shorten the element itself. The knitted article is stretched in front of an end of one of the two telescopic portions and fixed onto the other portion. Telescopic extension of the column element causes stress on the fabric of the knitted article which is in front of the end of the column element, where the breaking members and sensors are positioned.

When a cutting or perforating member stably associated with the device is provided, this may be carried by the movable second portion of the column element to move therewith with respect to the movable first portion of the column element. To perform perforation or cutting of the knitted fabric, the cutting or perforating member is extracted through a slot or opening provided on a front surface of the column element on which the knitted article is positioned and stretched.

Further features and embodiments of the device will be described in the attached claims, which form an integral part of the present description.

According to a further aspect, the invention relates to a method for testing resistance of a knitted article, in particular - but not exclusively - panty-hose, tights or a sock - by means of a device as defined above, comprising the steps of:

- loading and fixing a knitted article on the column element; - stretching the knitted article on the column element by extending said column element;

- cutting or perforating the knitted article stretched on the column element;

- detecting the run resistance of said knitted article.

The method may further comprise the steps of:

- increasing the elongation stress of said knitted article after cutting or perforation until a run is formed;

- detecting the run resistance of said knitted article based upon at least the stress applied on the knitted article when the run is forming.

According to a further aspect, the invention relates to a method for testing resistance of a knitted article, in particular a panty-hose or a sock, by means of a device as described above, comprising the steps of:

loading and fixing a knitted article on the column element; stretching the knitted article on the column element by extending said column element;

gradually increasing the stress of the knitted article until it breaks, detecting the applied stress;

detecting the breakage resistance of said knitted article based upon the stress under which breakage occurs.

Features and embodiments are described hereunder and further defined in the attached claims, which form an integral part of the present description. The above brief description identifies characteristics of the various embodiments of the present invention, in a manner that the detailed description below may be better understood and in order that the present contributions to the art may be better appreciated. There are obviously other characteristics of the invention which will be described further on and which will be indicated in the attached claims. With reference to this, before illustrating different embodiments of the invention in detail, it must be understood that the various embodiments of the invention are not limited in their application to the construction details and to the arrangements of components described in the following description or illustrated in the drawings. The invention may be implemented in other embodiments and implemented and placed in use in various ways. Also, it is necessary to understand that the phraseology and terminology used here are only for descriptive purposes and must not be considered as limiting.

Persons skilled in the art will therefore understand that the concept on which the description is based may be promptly used as a base for designing other structures, other methods and/or other systems to implement the various objects of the present invention. It is therefore important that the claims be considered as comprising those equivalent constructions which do not deviate from the spirit and scope of the present invention.

Brief description of the drawings

A more complete understanding of the illustrated embodiments of the invention and the many advantages achieved will be obtained with reference to the detailed description which follows in combination with the appended drawings, wherein:

figure 1 shows an axonometric view of a device according to the present invention; figures 2 and 3 show cross-sections according to two axial planes orthogonal to each other of the column element of the device of figure 1 in the idle position; figure 4 shows a cross-section similar to the one of figure 3 with the device in the step of stressing the knitted article;

figures 5 and 6 show cross-sections similar to the ones of figures 2 and 3 with the device in another configuration;

figure 7 shows a cross-section similar to the one of figure 6 in conditions of stress of the knitted article;

figure 8 shows a series of interchangeable protuberances of a knitted article breaking member.

Detailed description of an embodiment

The detailed description below of preferred embodiments is made with reference to the attached drawings. The same reference numbers in different drawings identify the equal or similar elements. Furthermore, the drawings are not necessarily scale. The detailed description below does not limit the invention. The protective scope of the present invention is defined by the attached claims.

In the description, the reference to "an embodiment" or "the embodiment" or "some embodiments" means that a particular feature, structure or element described with reference to an embodiment is comprised in at least one embodiment of the described object. The sentences "in one embodiment" or "in the embodiment" or "in some embodiments" in the description do not therefore necessarily refer to the same embodiment or embodiments. The particular features, structures or elements can be furthermore combined in any adequate way in one or more embodiments.

Figure 1 shows schematically and in an axonometric view a device for performing resistance tests on panty-hose, socks or similar tubular knitted articles, indicated as a whole with the number 1. In the context of the present description and the attached claims, the term "tubular" referred to a knitted article must be intended as also including complex knitted articles, presenting at least one tubular portion. For example, panty-hose or tights which have two leg portions are also comprised in the broad concept of tubular article. Although reference will be made below specifically to a tubular knitted article, to which the device is specifically dedicated, the possibility of using said device also to perform resistance tests on non-tubular knitted articles, for example on items of clothing such as bodysuits, underpants or similar, is not excluded.

In the embodiment illustrated in Figure 1 , device 1 comprises a base 3 inside which the actuators, a power supply unit, an electronic control unit, generically and schematically indicated with number 4, and other electronic or mechanical components for performance of the tests can be housed. The base 3 can have command buttons 5, 7 and a possible panel or display 9, for example of the touchscreen type, to display the test process data and/or enter commands in the device.

In the illustrated embodiment, the device 1 comprises a column element 11 supported by the base 3. In this embodiment, the column element 11 comprises a first portion 11A fixed with respect to the base 3 and a second portion 11B movable telescopically according to the double arrow fl 1 along the direction of axis A-A of the column element 11. Inside the column element 11 there are members which will be described below with specific reference to figures 2 to 6.

In the illustrated embodiment, the fixed first portion 11A of the column element 11 is formed of a substantially tubular element extending from the base 3. This configuration is particularly advantageous because it simplifies the method of blocking the knitted article on the column element, as will be explained below. However, the possibility of the first portion of the column element being formed of a part of the base 3, for example by a portion of the base 3 surrounding the portion of the column element extending vertically from the base itself, is not excluded. In this case, at least one zone of the base forms the fixed first portion of the column element. The second portion of the column element may be formed, in this case, of a tubular element partially housed in the base 3 and extendable or retractable by altering the length of the part of said movable portion projecting from the upper surface of the base 3.

A fastening element 13 is associated with the column element 11, serving to block a tubular knitted article on the fixed first portion 11 A of the column element 11 , as will be clarified below. In the illustrated embodiment, the fastening member 13 comprises a ring formed of two portions 15A and 15B pivoted to one another at 17 and carried by a bracket 19, which is fixed to the base 3 of the device 1. A toggle member 21 enables closing of the ring 15 A, 15B around the fixed portion 11A of the column element 11. The size of the ring 15 A, 15B is such as to obtain in this manner blocking of the tubular knitted article on the outer surface of the fixed first portion 11A of the column element 11. For a better fastening effect, the inner surface of the two portions 15 A, 15B forming the ring may be coated in a material with a high coefficient of friction and preferably deformable, for example rubber.

It must be understood that the fastening member may also be configured in a different manner. For example, a fastening member could be provided which is entirely unconnected to the base 3, for example formed of two ring portions which the operator may apply around the column element 11 and fix one to the other with a closure mechanism.

Closure of the ring may be obtained with mechanisms different from a toggle. For example, screw or snap-on means may be used.

In other embodiments, the fastening member may be carried directly by the column element 11, for example it could comprise a component sliding and blockable along the substantially cylindrical outer surface of the fixed first portion 11 A of the column element 11.

The inner configuration of the column element 11 is illustrated, in particular, in figures 2 and 3, which show said column element 11 in two longitudinal cross- sections according to planes containing axis A-A of the column element 11 and orthogonal one to the other.

In the illustrated embodiment, the movable second portion 1 IB of the column element 11 is guided on the external surface of the fixed first portion 11 A, for example by means of one or more guide rings 11C. In other embodiments, the movable second portion 1 IB could be housed inside rather than outside the movable first portion 11 A. The movable second portion 1 IB of the column element 11 has an end cover 23 forming a front surface 25, extending transversally to the axis A-A of the column element 11. Preferably, the front surface 25 has a portion orthogonal to the axis A-A.

The cover 23 is fixed to an inner block 27 housed in the movable second portion 1 IB of the column element 11. In the illustrated embodiment, the block 27 is connected to a hollow rod 29 which, at the opposite end with respect to the one to which the block 27 is connected, supports a nut screw 31. In this embodiment, the nut screw 31 engages with a threaded bar 33 extending coaxially inside the fixed first portion 11A of the column element 11. The number 35 schematically indicates a motor-reducer controlling rotation of the threaded bar 33. By means of the motor- reducer 35, it is thus possible to impart a movement according to the double arrow fl l to the nut screw 31, to the hollow rod 29 and to the block 27 which, being connected to the movable second portion 1 IB of the column element 11, transfers the translation movement thereto.

In other embodiments, not shown, different mechanisms may be used for moving the movable second portion 11B of the column element 11 according to double arrow f 11. For example, a pinion and rack mechanism, a linear electric motor or other mechanisms may be provided.

In the illustrated embodiment, two load sensors are advantageously associated with the movable second portion 11B of the column element 11, for example two load cells 37. In the illustrated embodiment, the two sensors 37 are arranged symmetrically, staggered by 180°, around axis A-A of the column element 11. In other embodiments, a single sensor could be provided, or a number of sensors larger than two, for example three sensors or four sensors, preferably staggered around the axis A-A of the column element 11 according to a uniform angular pitch.

In the illustrated embodiment, the sensors 37 are housed between the block 27 and the cover 23, so as to remain entirely housed inside the movable second portion 1 IB of the column element 11.

In order to detect a load proportional to the load applied on the tubular knitted article to be subjected to the resistance test, a load transfer unit is associated with each sensor 37, i.e. an element which transfers a reaction force corresponding with the stress applied to the tubular knitted article from the outside to the inside of the movable second portion 11B of the column element 11 and, more precisely, on corresponding sensor 37. In the embodiment illustrated in the drawing, these load transfer units, indicated with 39, comprise cursors housed sliding inside sliding seats 41 in the cover 23. Preferably, each cursor 39 forming a respective load transfer unit has two opposing end heads, the first indicated with 39A acting on the corresponding load cell or sensor 37 and the other, indicated with 39B, interacting directly or indirectly with the tubular knitted article to be subjected to the resistance test, as will be more apparent from what is described below.

In the illustrated embodiment, the device is equipped with various breaking members which act on the tubular knitted article to be subjected to the resistance test. Breaking member is generically intended as any member which serves to apply a mechanical stress on a tubular knitted article to be subjected to the resistance test until it causes irreversible damage, leading to breakage of some of the loops comprising the article.

In the embodiment illustrated, a first breaking member is associated with the column element 11, comprising a cutting or perforating member 43. The cutting or perforating member 43 may comprise a blade, for example with two cutting edges converging towards a sharp end, as visible in cross-section in figure 3. In another embodiment, the cutting or perforating member may comprise a tip, for example pyramid-shaped, or a blade with a single inclined cutter or any other member serving to perforate or cut the filaments forming the tubular knitted article to be subjected to the resistance test.

The cutting or perforating member 43 is housed entirely under the front surface 25 when it is not in operation. The front surface 25 has a slot 25A through which the perforating or cutting member 43 may be extracted to pass from the non- operating position, wherein it is housed inside the column element 11 (figures 2 and 3), to the extracted position (figure 4).

An actuator 45 may be provided to control the extraction and retraction movement (double arrow f43) of the cutting or perforating member 43. In an advantageous embodiment, the actuator 45 may be a pneumatic or hydraulic type actuator. In other embodiments, the actuator 45 may be an electromagnetic actuator, for example a cursor or movable anchor controlled by an electrically excited coil.

Preferably, the unit comprising the cutting or perforating member 43 and the respective actuator 45 is forced to move together with the movable second portion 1 IB of the column element 11. For this purpose, the unit 43, 45 may advantageously be mounted inside a housing 47 in the block 27 inside the movable second portion 1 IB of the column element 11.

With reference to figures 2 to 4, a first type of resistance test will now be described, which may be performed on a knitted article, preferably tubular in shape, such as a sock or panty-hose. The latter is indicated with M in figures 3 and 4. As schematically illustrated in these figures, a portion of tubular knitted article M is blocked on the fixed first portion 11 A of the column element 11 by means of the fastening member 13, which in these figures is schematically depicted as a ring surrounding said fixed first portion 11 A. In figure 4 the tubular knitted article M has been positioned lightly stretched so as to adhere to the transverse front surface 25 of the movable portion 11B of the column element 11. More precisely, the tubular knitted article M rests on the cursors 39 forming the load transfer units which transfer the load applied on them by the tubular knitted article M to the sensors 37. In the embodiment illustrated, in addition to the two support areas of the tubular knitted article M defined by the heads 39B of the force transferring units 39, two auxiliary support surfaces are provided, formed of the heads 51A of two pins 51 housed in seats 53 in the cover 23 or in sleeves 55 advantageously fixed on the cover 23 and extending towards the inside of the column element 11. The function of these seats 53 will become more apparent with reference to arrangement of the device illustrated in figures 5, 6 and 7.

In the illustrated embodiment, only two pins 51 and two seats 53 are provided, arranged in diametrically opposing positions and staggered by 90° with respect to the load transfer units 39 and the load sensors 37. In other embodiments, a different number of pins 51 and respective seats 53 may be provided, for example three seats 53 and three pins 51 arranged preferably at 60° one from the other. In other embodiments, the pins 51 may also be associated with load cells or force sensors housed under the cover 23.

After blocking the tubular knitted article M as illustrated in figure 3, the motor-reducer 35 is activated which, by means of the threaded bar 33 and the nut screw 31 , causes upwards translation of the movable second portion 11B of the column element 11. The reciprocal telescopic extension movement of portions 11 A, 1 IB forming the column element 11 causes an increase in the elongation stress of the tubular knitted article M. This elongation is transmitted onto the load sensors 37 by the load transfer units 39. The sensors 37 are connected to the central control unit 4, see figure 1. The detected load may be displayed on display 9. In some embodiments of the test procedure described herein, the upwards movement of the movable portion 1 IB of the column element 11 is arrested when a preset value of the load detected by the sensors 37 is reached. This load value is chosen in a manner to cause stretching without breakage of the tubular knitted article M.

When this load value is reached and the movable second portion 11B of the column element 11 is arrested, the actuator 45 is activated, causing extraction of the cutting or perforating member 43, which will cut or perforate the tubular knitted article M in a central zone of the portion of the tubular knitted article which is positioned on the front surface 25 of the movable second portion 1 IB of the column element 11. Figure 4 shows the column element 11 after extraction of the cutting or perforating member 43.

Two situations may occur at this point: perforation or cutting of the tubular knitted article M causes the start and propagation of a run, indicated with S in figure 4. Vice versa, if the tubular knitted article has a higher run resistance, after cutting or perforation, the surrounding knit remains intact. When a situation of this kind occurs, a second resistance test phase is performed, which consists in restarting the raising movement of the movable second portion 11B of the column element 11 with a further elongation of the tubular knitted article M. At a certain point, the elongation induced by extension will be such as to cause formation of a run S. The system is thereby able to identify the load value, detected by the sensors 37, which has caused the run. This parameter is an element of evaluation of the resistance of the tubular knitted article. Formation of the run causes lowering of the load applied to the sensors, which can be detected automatically and possible displayed on the device display. The device is therefore capable of detecting and possibly displaying and/or storing the maximum value of stress applied until detection of the run-starting, identifiable by means of a sudden drop or discontinuity of stress detected by the sensors.

In order to perform a different type of resistance test of the tubular knitted article M, according to an advantageous embodiment, the test device 1 may be equipped with a different accessory, as schematically indicated by figures 5, 6 and 7. The elements of the device already described with reference to figures 1 to 4 are indicated in figures 5 to 7 with the same reference numbers and will not be described again.

As may be observed in particular in figure 6, in this arrangement of the test device 1, the pins 51 of the seats 53 housing them have been eliminated, vice versa there are pins or rods 61 in said seats, which are integral to a component 63 comprising a different member for breaking the tubular knitted article. In this embodiment, the component 63 has a substantially conical shape, the pins 61 being rigidly connected to the component 63 protruding from the base of the cone to be inserted in the seats 53. The dimensions of the seats 53 and the rods 61 are such as to allow a substantially free and friction-free movement of the component 63 with respect to the movable second portion 11B of the column element 11. In idle conditions, the component 63 rests (see figure 5) with its lower base 63A against the heads 39B of the pins 39 which form the load transfer units. In this manner, when a force is applied in a vertical direction, i.e. parallel to the axis A-A of the column element 11 on the conical component 63, this force is transmitted by means of the load transfer units 39 to the underlying load sensors 37 which may detect the stress and quantify it.

In the illustrated embodiment, a shaped protuberance 65 is reversibly connected to the component 63. The shaped protuberance 65 may be equipped with a threaded tang 65A through which it is fixed into a threaded blind hole in the component 63.

The shape and size of the shaped protuberance 65 can vary as a function of the characteristics of the knitted article to be tested, the type of test to be performed or other factors. In some embodiments, a plurality of interchangeable shaped protuberances 65 may be provided. Figure 8 shows examples of some possible shaped protuberances 65 of various shapes and size, all usable interchangeably on the component 63. In other embodiments, a plurality of components 63 may be provided, having different and non-interchangeable protuberances. In general, the shaped protuberances 65 have the shape of a solid of revolution, with no corners, protuberances or cutting edges. The example in figure 8 shows ovoid or approximately spherical shaped protuberances, with variable radius of curvature and dimensions.

Operation of the device in this arrangement will now be described with reference to figures 6 and 7. In figure 6, the tubular knitted article M has been inserted onto the column element 11 and blocked in its lower part by means of the fastening member 13 against the fixed first portion 11A of the column element 11, in an the same manner as described above with reference to the test performed in the arrangement described in figures 2 to 4.

In the initial phase, the tubular knitted article M is only lightly stretched to adhere against the shaped protuberance 65 associated with the component 63. Starting with this arrangement and powering the motor-reducer 35, the movable second portion 11B of the column element 11 is raised according to the arrow fl l, while the cutting or perforating member 43 remains fully housed inside the movable second portion 11B of the column element 11 and, in any case, remains underneath the component 63.

While the motor-reducer 35 causes gradual telescopic extension of the column element 11, the sensors 37 detect the load transmitted thereon by the load transfer units 39, corresponding with the stress applied to the tubular knitted article M. The raising movement of the movable portion 11B and therefore the telescopic extension of the column element 11 continues up to the breaking point of the tubular knitted article caused by the thrust of the shaped protuberance 65. The central control unit 4 is capable of detecting the value of the force measured by the sensors 37 at the moment when breakage of the tubular knitted article M starts, thereby providing a further parameter of breakage resistance of the knitted article.

The tests described above may be performed on various samples of a tubular knitted article M to test resistance to running and resistance to breakage in the various areas or zones of the knitted article. For example, it is possible to test the zones which are the most stressed during practical use of the tubular knitted article. Typically, resistance tests may be performed in the ankle, knee, thigh or crotch area.

The device may be programmed to perform several tests on several samples in various zones of said samples, storing not only the test result, but also the area in which it has been performed.

Device 1 may be equipped with wireless or cabled communication ports, with peripherals, for example printers, mass storage devices, external monitors, etc., or with an electronic processor, for better display of the test results, to store and/or process results and/or to print the test results.

The embodiments described here and illustrated in the drawings have been explained in detail as examples of embodiments of the invention. It will be clearly apparent to those skilled in the art that modifications, variants, additions and omissions are possible, without however departing from the principles, the scope of the concept and the teachings of the present invention as defined in the attached claims. The scope of the invention shall be therefore determined based upon the widest interpretation of the attached claims, comprising in this scope these modifications, variants, additions and omissions. The term "to comprise" and its derivatives do not exclude the presence of further elements or steps in addition to those specifically listed in a given claim. The term "a" or "an" before an element, means or feature of a claim does not exclude the presence of a plurality of these elements, means or features. If a claim of a device claims a plurality of "means", some or all of these "means" can be actuated by a single component, member or structure. The enunciation of given elements, features or means in distinct depending claims does not exclude the possibility of combining said elements, features or means together. When a method claim lists a sequence of steps, the sequence with which these steps are listed is not binding and can be changed, if the particular sequence is not indicated as binding. Any reference numbers in the appended claims are provided to facilitate reading of the claims with reference to the description and to the drawing, and do not limit the scope of protection represented by the claims.