VERSTRAETE, Jonathan (Dorpsplein 32/1, Sint-Eloois-Winkel, B-8880, BE)
LECLUYSE, Johan Maria Albert (Lindenpark 19, Deurle, B-9831, BE)
VERSTRAETE, Jonathan (Dorpsplein 32/1, Sint-Eloois-Winkel, B-8880, BE)
| Claims . 1.- Velcro fastener with improved antistatic properties, and which fastener (1) consists of a male Velcro strip (2) with hooks (8) on at least one side and a female Velcro strip (3) with loops (9) on at least one side, whereby the hooks (8) and loops (9) latch onto one another when the two Velcro strips (2 and 3) are pressed together, and whereby the Velcro strips (2 and 3) are formed as a support (4) consisting of a matrix of woven warp threads (5) and weft threads (6), between which pile threads (7) are woven to form the pile protruding from the support (4) in the form of hooks (8) or loops (9), characterised in that for the male Velcro strip (2) there is at least one electrically conductive warp thread (5G) and at least one electrically conductive pile thread (7G) woven in that are in contact with one another, while in the female Velcro strip (3) there is at least one electrically conductive pile thread (7G) woven in whose loop-shaped pile (9) , in a closed fastener (1), is in electrical contact with the hook-shaped pile (8) of the conductive pile thread (7G) of the male Velcro strip (2} . 2.- Velcro fastener according to claim 1, characterised in that the conductive pile threads (7) and warp threads (6) are formed by a plastic thread with a conductive coating, preferably a carbon coating. 3.- Velcro fastener according to claim 2, characterised in that the coating is fixed in the matrix of the material from which the thread is manufactured, for example by burning in the carbon coating. 4. - Velcro fastener according to any one of the foregoing claims, characterised in that the warp threads (5) are made from polyamide 6. 5. - Velcro fastener according to any one of the claims 2 to 4, characterised in that the pile threads (7) are made from polyamide 6.6. 6. - Velcro fastener according to any one of the foregoing claims, characterised in that the pile threads (7) of the male Velcro strip (2) are monofilament threads. 7. - Velcro fastener according to any one of the foregoing claims, characterised in that the pile threads (7) of the female Velcro strip (3) are multifilament threads. 8. - Velcro fastener according to any one of the foregoing claims, characterised in that the electrically conductive pile thread (7G) of the male Velcro strip (2) is flanked by at least one electrically conductive warp thread (5G) on each side of the pile thread (7G) , and which is in contact with the electrically conductive pile thread (7G) concerned or the hook-shaped pile (8) of it. 9. - Velcro fastener according to any one of the foregoing claims, characterised in that the male Velcro strip (2) only contains one single conductive pile thread (7G) . 10. - Velcro fastener according to any one of the foregoing claims, characterised in that the female Velcro strip (3) has a band (10) that extends in the longitudinal direction of the Velcro strip over a certain width (D) of the Velcro strip (3), and over which the electrically conductive pile threads (7G) are distributed. 11. - Velcro fastener according to claim 10, characterised in that the aforementioned band (10) extends over a width (D) of approximately five millimetres. 12. - Velcro fastener according to any one of the foregoing claims, characterised in that the conductive threads (5G and 7G) are situated in or around the middle of the Velcro strips (2 and 3) . |
The present invention relates to a Velcro fastener with improved antistatic properties.
A Velcro fastener generally consists of two Velcro strips that can attach to one another, whereby one Velcro strip is the male part of the fastener, which has hooks protruding out of the support at least on one side, while the other Velcro strip is the female part of the fastener, which has loops on at least one side.
When the male and female parts are brought together the hooks latch onto the loops such that the parts fasten together.
Both parts primarily consist of a woven support formed by a matrix of warp threads and weft threads, between which pile threads are woven to form the pile protruding out of the support that forms the aforementioned hooks or loops.
The warp threads and the weft threads, as well as the pile threads, are generally made from a plastic material, such as polyamide, that is not electrically conductive.
This means that the Velcro fastener can become charged with static electricity, which constitutes a potential hazard from sparks, which, when the Velcro fastener is used in an explosive or inflammable environment, can lead to disastrous consequences. Velcro fasteners are already known that have a conductive thread worked into the Velcro strips and which extends in the longitudinal direction of the Velcro strips.
As a result static electricity can by guided away from the Velcro fastener by connecting the Velcro strip to an earth.
This is used for example in fasteners for bags for the storage of bulk products, such as powders or similar, in which such explosive conditions may arise.
Such bags are often of a double-walled construction with an inner bag and an outer bag, in which the inner bag is secured to the outer bag by means of a Velcro fastener.
In such double-walled bags there is still always a danger of static electricity discharging from the inner bag to the outer bag, with all the associated hazards.
The present patent applicant explains this through the fact that in the known Velcro fasteners, the static electricity can only flow away in the longitudinal direction and thus not in the transverse direction through the Velcro fastener, such that it forms an insulator between the two bags as it were.
The purpose of the present invention is to provide a solution to at least one of the aforementioned disadvantages and other disadvantages. To this end the invention is a Velcro fastener with improved antistatic properties, and which fastener consists of a male Velcro strip with hooks on at least one side and a female Velcro strip with loops on at least one side, whereby the hooks and loops latch onto one another when the two Velcro strips are pressed together, and whereby the Velcro strips are formed as a support consisting of a matrix of woven warp threads and weft threads, between which pile threads are woven to form the pile protruding from the support in the form of hooks or loops, with the characteristic that for the male Velcro strip there is at least one electrically conductive warp thread and at least one electrically conductive pile thread woven in that are in contact with one another, while in the female Velcro strip there is at least one electrically conductive pile thread woven in whose loop-shaped pile, in a closed fastener, is in electrical contact with the hook-shaped pile of the conductive pile thread of the male Velcro strip .
A Velcro fastener according to the invention has the advantage that not only can it conduct the static electricity away in the longitudinal direction of the Velcro fastener, but also in the transverse direction through the fastener via the contact between the conductive piles of the male and female Velcro strips and the conductive warp tread of the male Velcro strip.
As a result such a Velcro fastener can also be used in cases where there is a risk of static electricity discharging between the fabrics or other objects that are joined together by the fastener, such as in the aforementioned case of the double-walled bulk bags. In this case a simple earthing of the fabrics or objects concerned, or of the Velcro fastener, is sufficient to guide the static electricity away to earth and thus to rule out all risks of sparks.
As is known, the hooks of the male Velcro strip are formed by loops of the pile threads that are then cut through.
Because the loops of the conductive pile thread of the male Velcro strip are cut through, the electrical conductivity of this pile thread is broken at the point of these cuts and this pile thread is, as it were, divided into electrically conductive parts that form the hooks.
The electrical breaks at the point of the cuts are however restored again by bringing the hooks into contact with the electrically conductive warp thread of the male Velcro strip.
Preferably the conductive pile threads (7) and warp threads are formed by a plastic thread with a conductive coating, preferably a carbon coating.
Thus the strength of these threads is preserved and the Velcro fastener will not be weakened by the application of the invention. According to a practical embodiment, the coating is fixed in the matrix of the material from which the thread is made, for example by burning in the coating. In this way the conductivity of the conductive threads is preserved and the conductivity is not affected by washing, for example .
Preferably only one conductive pile thread is provided in the male Velcro strip, flanked on one or both sides by a single conductive warp thread, such that the additional cost of such conductive threads for the male Velcro strip can be kept to a minimum. The female Velcro strip on the other hand preferably has a band in which the pile threads are conductive pile threads, whereby this band extends in the longitudinal direction of the Velcro strip and over a certain width, for example approximately five millimetres.
This provides the advantage that the male and female Velcro strips do not have to be perfectly aligned with one another to make a contact between the conductive pile of the male Velcro strip and the conductive pile of the female Velcro strip, but this contact is also realised when the two Velcro strips are shifted breadthways with respect to one another .
With the intention of better showing the characteristics of the invention, a preferred embodiment is described hereinafter by way of an example, without any limiting nature, of a Velcro fastener according to the invention with improved antistatic properties, with reference to the accompanying drawings, wherein: figure 1 schematically shows in perspective a Velcro fastener according to the invention with a male part with hooks and a female part with loops,
figure 2 shows a cross-section along the line II-II in figure 1.
figure 3 shows a top view on a larger scale of the part indicated by F3 in figure 3.
figure 4 shows a cross-section such as that of figure 2, but for a different position. The Velcro fastener 1 shown in figures 1 and 2 is formed by two Velcro strips, respectively a male Velcro strip 2 and a female Velcro strip 3, that are brought together to fasten to one another. The Velcro strips 2 and 3 are primarily formed by a support 4 consisting of a matrix of warp threads 5 and weft threads 6 woven together, between which pile threads 7 are woven to form the pile in the form of hooks 8 for the male Velcro strip 2 or in the form of loops 9 for the female Velcro strip.
In the example shown, the hooks 8 and loops 9 are on one side of the support 4 and protrude out with respect to this side, although it is not excluded that both sides of the support 4 have such hooks 8 or loops 9. As can be seen in figure 2, the hooks 8 latch onto the loops 9 when the two Velcro strips 2 and 3 are pressed together and thus form an attachment that, as is known, can again be released by pulling the Velcro strips 2 and 3 away from one another.
The warp threads 5 and weft threads 6, as well as the pile threads 7 are made from a plastic that is not electrically conductive, for example a polyamide.
The pile threads 7 of the male Velcro strip are made from polyamide 6.6, for example, while all other threads of the male and female Velcro strips 2 and 3 are made from polyamide 6, for example.
For the pile threads 7 of the female Velcro strip 3, a multifilament thread is generally used, while the other threads of the male and female Velcro strips 2 and 3 are generally monofilament threads.
According to the invention the two Velcro strips 2 and 3 have pile threads 7G that are electrically conductive and are situated such that when the Velcro strips 2 and 3 are attached to one another, the hook-shaped pile 8 of the conductive pile threads 7G of the male Velcro strip 2 are in electrical contact with the loop-shaped pile 9 of the conductive pile threads 7G of the female Velcro strip 3.
The hook-shaped pile 8 of the male Velcro strip 2 is in fact obtained during the production process of the Velcro strip 2, from a loop-shaped pile that is cut. The hook-shaped pile 8 of the conductive pile threads 7G of the male Velcro strip 2 are obtained in the same way by cutting through the originally formed loops of the conductive threads 7G.
Thus for the male Velcro strip 2 the electrically conductive pile threads 7G are cut through and these pile threads 7G are divided into a large number of hooks 8, electrically insulated from one another.
In order to restore the electrical conduction between the hooks 8, in the male Velcro strip 2 an additional electrically conductive warp thread 5G is woven in, next to each electrically conductive pile thread 7G, that is in contact with the electrically conductive pile thread 7G or at least with the hooks of this pile thread 7G.
For the example shown in the drawings, the male Velcro strip 8 only has one single electrically conductive pile thread 7G that is in the middle of the Velcro strip, and which is flanked by two electrically conductive warp threads 5G, one on each side of the pile thread 7G as shown in figure 3, although one single electrically conductive warp thread 5G in contact with the thread 7G could be sufficient, and thus could also belong to the possibilities .
For the female Velcro strip 3 of the example, the electrically conductive pile threads 7G are spread over a band 10 that is in the middle of the Velcro strip 3, and which extends in the longitudinal direction of the Velcro strip 3 over a width D of the Velcro strip 3, which for example is five millimetres. It is clear that when the two Velcro strips 2 and 3 are attached to one another, there is electrical conduction that can guide away the static electricity in both the longitudinal direction of the Velcro strips 2 and 3, as shown by the double arrow A in figure 1, and in the transverse direction through the Velcro fastener 1, as shown by the double arrows B in figures 1 and 2.
It is clear that this conductivity in the transverse direction B requires the hook-shaped pile 8 of the electrically conductive pile threads 7G of the male Velcro strip 2 to be in electrical contact with the loop-shaped pile 9 of the electrically conductive pile threads 7G of the female Velcro strip 3. It is also clear that due to the fact that the band 10 has a certain width, this contact is also assured when the Velcro strips 2 and 3 of the closed Velcro fastener 1 are shifted widthways over a certain distance with respect to one another, as shown in figure 4.
It is clear that for the two Velcro strips 2 and 3, it is sufficient for there to be one single electrically conductive pile thread 7G, whereby it must be ensured in such a case that the Velcro strips 2 and 3 are properly aligned with one another breadthways to ensure the electrical contact between the two Velcro strips 2 and 3. It is of course not excluded that the male Velcro strip 2 also has a wider zone over which electrically conductive pile threads 7G are distributed, and this in combination with a band 10 or only one single pile thread 7G on the female Velcro strip 3.
Preferably the conductive threads are obtained by giving the threads that are normally used a conductive coating, for example carbon, whereby this coating is preferably fixed in the matrix of the material from which the thread is manufactured, for example by burning in the coating. In this way a conductive thread is obtained in a relatively simple and cheap way from a basic thread that is available in any case.
Thus warp threads of polyamide 6 can be used and pile threads of polyamide 6.6, that have been given a conductive coating or otherwise.
The present invention is by no means limited to the embodiments described as an example and shown in the drawings, but a Velcro fastener according to the invention with improved antistatic properties can be realised in all kinds of variants, without departing from the scope of the invention.