Apparatus for attaching touch fasteners with self-heating attachment adhesive

Apparatus for attaching touch fastener material capable of self-bonding to a porous surface such as fabric and the like by the application of an electrical current therethrough. The material comprises a backing material with front and rear surfaces and having one portion of a touch fastening system on the front surface thereof. A layer of thermoplastic and thermosetting adhesive is bonded to the rear surface. Heat generating means are incorporated into the layer of adhesive for producing sufficient heat in the adhesive when a low voltage and high current electrical source is applied therethrough to cause the adhesive to adhere to a porous surface with which it is in contact. In one embodiment, the heat generating means comprises a strip of metal foil embedded within the layer of adhesive. In a second embodiment, the heat generating means comprising a plurality of electrically conductive/resistive particles embedded within the layer of adhesive. The apparatus includes embodiments having a roller and band moving in combination, a pair of opposed rollers, and mirror imaged feet moving in the manner of a sewing machine drive foot. Each embodiment includes contact pins for contacting the adhesive passing low voltage high current electricity therethrough.

BACKGROUND OF THE INVENTION 
The present invention relates to touch fastener materials and their 
attachment to surfaces and, more particularly, to apparatus for attaching 
touch fastener material capable of self-bonding to a surface such as 
fabric and the like by the application of an electrical current 
therethrough wherein such apparatus comprises apparatus for attaching 
touch fastener material having a backing material with front and rear 
surfaces and having one portion of a touch fastening system on the front 
surface thereof, a layer of thermoplastic/thermosetting adhesive bonded to 
the rear surface, and, an electrically conductive/resistive material 
incorporated into the layer of adhesive capable of producing sufficient 
heat in the adhesive when a low voltage and high current electrical source 
is applied therethrough to cause the adhesive to adhere to the surface of 
an article with which it is in contact, wherein the apparatus comprises 
support means for supporting the article with the surface thereof exposed 
and the touch fastener material disposed thereon; compression means for 
releasably bearing against the front surface of the touch fastener 
material to hold it and its adhesive against the surface of the article; a 
plurality of contact means for releasably making electrical contact with 
the electrically conductive/resistive material in the adhesive when the 
compression means is bearing against the front surface of the touch 
fastener material; and, electrical means for applying low electrical 
current to flow through the electrically conductive/resistive material in 
the adhesive between respective ones of the contacts to heat the adhesive 
to its point of melting and adhesion. 
Touch fastening systems such as those sold by the assignee of the present 
application under the trademark VELCRO are well known in the art and are 
continually being adapted to new uses as their value and ease of use 
becomes more and more recognized and appreciated. As used herein, the term 
"touch fastener", and similar designations, refers to a first planar 
backing material having a surface carrying hooks, mushrooms, balls on 
stems, pigtails, or the like, capable of engaging loops, hooks, mushrooms, 
balls on stems, pigtails, or the like carried by a second planar backing 
material to releasably fasten components together. In this specification 
"touch fastener" shall also be construed to include zip fasteners and 
buttons, press studs and the like when attached to a planar backing for 
mounting to a component. For convenience only, hook and loop type touch 
fastening material is shown in the drawings. 
Where porous materials and surfaces are involved, a popular method of 
attaching or bonding the touch fastener materials to the components is the 
use of heat-activated adhesives of a type well known in the art which are 
thermosetting and thermoplastic in nature. Often, the heat-activated 
adhesive can be applied by injecting it from a hot extruding "gun" between 
two surfaces to be joined (or deposited onto one of them) and then 
pressing the surfaces together while the adhesive is in its thermoplastic 
state. 
There are many applications involving the application of touch fastener 
materials with adhesive, however, where the use of a so-called "glue gun" 
is not an approach of choice. For example, such a situation exists where 
lightweight fabrics are involved, as opposed to applications employing 
canvas, or the like, where spot fastening with a glue gun is not a 
problem. Were there an alternative manner of applying the touch fastener 
materials with the adhesive in such more delicate applications, it would 
be gratefully accepted and adopted. In my co-pending application titled 
TOUCH FASTENER WITH SELF-HEATING ATTACHMENT ADHESIVE, filed on even date 
herewith and assigned to the assignee of this invention, I disclosed touch 
fastening materials incorporating pre-applied heat-activated 
thermoplastic/thermosetting adhesives which are self-heating through the 
application of an electrical current therethrough. 
Touch fastener material according to the above-referenced co-pending 
application in one embodiment thereof is shown in FIGS. 1-4. The material 
itself is shown in exploded view in FIG. 1 and generally indicated therein 
as 10. The material 10 comprises a strip of touch fastener material 12 
with a self-heating adhesive on the back surface thereof. For purposes of 
description only, the touch fastener material 12 is a conventional piece 
of the hook portion of hook and loop type fastening material comprising a 
porous backing material having a plurality of engaging hooks on the front 
surface thereof. The adhesive comprises a first layer 14 of thermoplastic 
adhesive of a type generally well known in the art and commercially 
available from any sources. A strip of electrically conductive/resistive 
metal foil 16, such as aluminum foil, is disposed between the first layer 
14 of adhesive and a second layer 18 of the same material. In the form as 
intended for commercial sale ready for attachment, the components of FIG. 
1 are heat bonded together as shown in FIG. 2. The layers 14, 18 of 
adhesive are bonded to the foil 16 and the first layer 14 of adhesive is 
bonded to the back surface of the touch fastener material 12. 
To attach the touch fastener of the present invention to a strip of fabric 
20, for example, it is positioned as shown in FIG. 3 with the second layer 
18 of adhesive contacting the fabric 20. A plurality of contact pins 22 
are then pushed through the touch fastener material 12 and/or the fabric 
20 into contact with the foil 16. Alternative pins 22 are connected to 
positive (+) and negative (-) low voltage sources having high current 
capability and the high current is caused to flow through the foil 16 
between the pins 22 causing the foil 16 to heat due to its electrical 
resistance and thereby heat the layers 14, 18 of adhesive to their 
thermoplastic/thermosetting level. Second layer 18 thereupon bonds to the 
surface of the fabric 20. 
In a second embodiment of the material of the above-referenced co-pending 
application, the adhesive has electrically conductive/resistive particles 
mixed therein in place of the metal foil of the previously described 
embodiment. When the contact pins 22 are stuck into the adhesive, they 
make electrical contact with the particles. The particles, in turn, 
resistively conduct the current from one to another causing heat to be 
generated in the same manner as the foil. 
Since the material of the abovereferenced co-pending application did not 
exist until my invention thereof, there is, accordingly, no device for 
attaching it on a commercial or high production basis in the same way that 
a sewing machine can be used for easily and quickly performing sewing 
operations that would, otherwise, have to be accomplished by hand. 
Wherefore, it is the object of the present invention to provide apparatus 
for attaching the touch fastening materials of my co-pending application 
which incorporate pre-applied heat-activated thermoplastic/thermosetting 
adhesives which are self-heating through the application of an electrical 
current therethrough. 
SUMMARY 
The foregoing objective has been accomplished by the apparatus of the 
present invention for attaching touch fastener material having a backing 
material with front and rear surfaces and having one portion of a touch 
fastening system on the front surface thereof, a layer of 
thermoplastic/thermosetting adhesive bonded to the rear surface, and, an 
electrically conductive/resistive material incorporated into the layer of 
adhesive capable of producing sufficient heat in the adhesive when a low 
voltage and high current electrical source is applied therethrough to 
cause the adhesive to adhere to the surface of an article with which it is 
in contact, said apparatus comprising support means for supporting the 
article with the surface thereof exposed and the touch fastener material 
disposed thereon; compression means for releasably bearing against the 
front surface of the touch fastener material to hold it and its adhesive 
against the surface of the article; a plurality of contact means for 
releasably making electrical contact with the electrically 
conductive/resistive material in the adhesive when the compression means 
is bearing against the front surface of the touch fastener material; and, 
electrical means for applying low voltage electrical current to flow 
through the electrically conductive/resistive material in the adhesive 
between respective ones of the contacts to heat the adhesive to its point 
of melting and adhesion. 
In one embodiment, the compression means is a hollow cylindrical roller 
mounted for rotation about a longitudinal axis; the support means is a 
moving band disposed close adjacent the surface of the roller at one point 
and moving in a plane parallel to the longitudinal axis at the one point, 
the band being positioned and adapted to have the article and touch 
fastener material disposed thereon and to carry them between the band and 
the roller at the one point to be compressed therebetween as the roller 
rolls along the band; the plurality of contact means comprises a plurality 
of contact pins disposed within the roller; and additionally, a plurality 
of holes are circumferentially disposed in sidewalls of the roller for 
having the contact pins pass therethrough. Means are provided within the 
roller for urging the contact pins through respective ones of the holes to 
contact the adhesive at the one point and for retracting the contact pins 
into the roller when not adjacent the one point. 
In a second embodiment, the compression means is a first hollow cylindrical 
roller mounted for rotation about a longitudinal axis; the support means 
is a second hollow cylindrical roller mounted for driven rotation about a 
longitudinal axis parallel to the longitudinal axis of the first roller 
and disposed close adjacent the first roller at one point, the rollers 
being positioned and adapted to grip and pull the article and touch 
fastener material therebetween at the one point to be compressed between 
the rollers; the plurality of contact means comprises a plurality of 
contact pins disposed within the rollers. As with the previous embodiment, 
a plurality of holes are circumferally disposed in sidewalls of the 
rollers for having the contact pins pass therethrough and means are 
provided within the rollers for urging the contact pins through respective 
ones of the holes to contact the adhesive at the one point and for 
retracting the contact pins into the rollers when not adjacent the one 
point. 
In a third embodiment, planar worktable means are provided for supporting 
the touch fastener material and the article in combination on a top 
surface thereof, the worktable means having a longitudinal slot 
therethrough communicating between the top surface and a bottom surface 
thereof; the compression means is a first foot disposed above the slot; 
the support means is a second foot disposed below the slot, the feet being 
mirror images of one another and adapted to move in a driven pattern 
wherein they start from a first position at one end of the slot at 
positions opposed and separated from one another, then move towards one 
another to grip the touch fastener material and article in combination 
therebetween, then move along the length of the slot, then separate from 
one another to release the touch fastener material and article from 
therebetween, and then return to the first position; and additionally, the 
contact means comprise a plurality of contact pins disposed on facing 
surfaces of respective ones of the feet.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Apparatus according to the present invention in a first and basic 
embodiment adapted for batch processing is shown in FIGS. 5-8. As shown in 
FIG. 5, the apparatus, generally indicated as 24, comprises a support 
plate 26 adapted to have the fabric 20 (or other article to which 
attachment is to be made) placed on the top surface thereof with the touch 
fastening material 10 according to my above-referenced co-pending 
application placed on top of the fabric 20 with its self-heating adhesive 
layer 28 contacting the top surface of the fabric 20. A movable upper 
place 30 is positioned above and parallel to the support plate 26. A 
driver mechanism 32 is operably connected to the upper place 30 to move it 
between the raised position shown in FIG. 5 and a lowered position to be 
described shortly with respect to FIG. 6. Such driver mechanisms are well 
known to those skilled in the art and, therefore, in the interest of 
simplicity and to avoid redundancy, further description thereof is not 
included herein. The movable upper plate 30 carries a plurality of contact 
pins 22 electrically isolated from one another. In the preferred 
embodiment the pins 22 are in a regular pattern such as a rectangle of 
rows and columns or a helix so as to be regularly and evenly spaced from 
one another and thus cause even heating throughout the adhesive layer 28. 
Alternative pins 22 are connected, respectively, by wires 34 and 36 to 
positive (+) and negative (-) electrical potentials. For simplicity, the 
electrical connections have been eliminated from the remaining figures 
relating to this embodiment. 
The pins 22 are preferably heated to maintain adhesive deposited thereon in 
a molten condition to permit the pins 22 to electrically conductively 
contact the foil. Here pin heating is achieved by electrical heating 
elements (not shown) disposed in plate 38 and connected to an electrical 
power supply 38a (FIG. 5 only). 
An ejection/pressure plate 38 is disposed between the upper plate 30 and 
the support plate 26. The ejection/pressure plate 38 has holes 40 
therethrough in alignment with the pins 22 such that the ejection/pressure 
plate 38 can fit over the pins 22. A driver mechanism 42 similar to driver 
mechanism 32 is operably connected to move the ejection/pressure plate 38 
between a raised position as shown in FIG. 5 wherein it is close adjacent 
the upper plate 30 and a lowered position to be described shortly with 
respect to FIG. 8. 
In operation, the upper plate 30 and ejection/pressure plate 38 are lowered 
in combination by the driver mechanisms 32, 42 to the positions of FIG. 6. 
This causes the pins 22 to pierce the touch fastener material 10 and 
electrically contact the self-heating adhesive layer 28. Simultaneously, 
the ejection/pressure plate 38 applies pressure to the top of the touch 
fastener material 10 to hold it and the adhesive layer 28 firmly against 
the top of the fabric 20. The electrical potential can be applied 
constantly to the pins 22 or selectively applied, as desired, since there 
is no conductivity path between the pins 22 when they are not in 
electrical contact with the adhesive layer 28. If it is desired or 
required to allow cooling of the adhesive under pressure, the electrical 
path to the pins 22 should be through a switch. Following the self-heating 
of the adhesive layer 28 from the flow of electrical current therethrough 
between the pins 22, the assembly appears as in FIG. 7 with the adhesive 
layer 28 bonded into the surface of the fabric 20. 
The upper plate 30 and ejection/pressure plate 38 are then raised in 
combination and the ejection/pressure plate moved to the ends of the pins 
22 by the driver mechanisms 32, 42 as depicted in FIG. 8. This ejects the 
bonded touch fastener material 10 and fabric 20 from the pins 22 and 
leaves space for them to be withdrawn from between the support plate 26 
and the ejection/pressure plate 38. 
While the apparatus of FIGS. 5-8 will work for batch operations such as 
spot fastening, and the like, in the manner of a stapling machine, for 
larger and more commercial operations there is a need for continuous feed 
attachment apparatus which operate in a manner such as sewing machines do 
with respect to sewing operations. Such apparatus in various embodiments 
according to the present invention will now be described. For simplicity 
and to avoid redundancy, only those portions of the apparatus relative to 
the specific problem of attaching my self-heating touch fastening material 
will be shown and described. The remaining portions of the apparatus are 
well within the capability of those skilled in the art to design without 
undue experimentation. 
A continuous feed apparatus, generally indicated as 44, employing a 
pressure roller and belt feet is shown in FIG. 9. The pressure roller is 
in the form of a hollow cylinder 46 supported for rotation about its 
longitudinal axis 48. Disposed within the pressure cylinder 46 is a 
contact roller 50 having the contact pins 22 disposed about its outer 
periphery. The contact roller 50 is adopted for rotation about support 
shaft 52 which is parallel to the axis 48 of pressure cylinder 46 and 
pressure cylinder 46 has slots or holes (not shown) in the sidewalls 
thereof through which the pins 22 can project as the cylinder 46 and 
roller 50 rotate. 
A pressure/feed band 54 is disposed over rollers 56 to be driven by motor 
58 as indicated by the arrows. The band 54 is positioned to bear against 
the cylinder 46 where the pins 22 on contact roller 50 pass through its 
walls. An electrical source 60 is connected to the contact roller 50 to 
provide the electrical potential to the contact pins 22. Additionally, it 
is preferred that first temperature control means 62 be operably connected 
to maintain the temperature of the band 54 at an optimum working 
temperature for each application. It is also preferred that second 
temperature control means 64 be operably connected to maintain the 
temperature of the pressure cylinder 46 at an optimum working temperature 
for each application as well. 
In operation to apply a strip of touch fastener material 10 to a strip of 
fabric 20, the two are fed between the pressure cylinder 46 and the band 
54 and moved therebetween by the movement of the band 54. As the pins 22 
emerge from the sidewalls of the pressure cylinder 46, they contact the 
self-heating adhesive and apply a high current therethrough in the same 
manner as described above. Thus, in the area labelled "HEATING AREA" in 
FIG. 9 the adhesive is caused to heat and bond to the fabric 20. The thus 
bonded materials 10, 20 are then moved into a "COOLING AREA" by the 
apparatus 44 as the pins 22 are continuously withdrawn therefrom and 
inserted into the area behind that which has just been heat bonded. 
A similar and alternate embodiment, generally indicated as 44', to that of 
FIG. 9 is shown in FIG. 10. The apparatus of FIG. 10 is substantially 
identical to that of FIG. 9 except that the contact roller 50 has been 
replaced by an elastomeric cylinder 66 disposed within the pressure 
cylinder 46 and adapted to rotate in combination therewith. The pins 22 
are carried by the cylinder 6 on the outer surface thereof and are 
disposed adjacent matching holes (not shown) in the sidewalls of the 
pressure cylinder 46 provided thereof. The elastomeric cylinder 66 passes 
over a deflection roller 68 which is positioned in the same manner as the 
contact roller 50 of the previous embodiment. As the pressure cylinder 46 
and elastomeric cylinder 66 revolve, the deflection roller 68 urges the 
pins 22 out through the adjacent holes in the sidewalls of the pressure 
cylinder 46 to contact the materials passing between the pressure cylinder 
46 and band 54 in the same manner as described above with respect to the 
apparatus 44 of FIG. 9. 
A variation on the above theme is shown in the apparatus of FIG. 11 wherein 
the band 54 has been replaced by a second pressure cylinder 70 identical 
to the pressure cylinder 46 of FIG. 10 disposed in opposition thereto so 
as to form a pinching action therebetween. Like the band 54, the pressure 
cylinder is rotated by a motor (not shown). The pressure cylinder 
configuration of FIG. 9 (or a combination thereof) could, of course, be 
used. The electrical connections in this instance are easier since the 
pins 22 of one of the cylinders 46, 70 can be connected to the positive 
(+) source while those of the other can be connected to the negative (-) 
source. The cylinders 46, 70 are disposed on opposite sides of a slot 72 
in a worktable 74 used to support the materials into and out of the 
bonding apparatus in the absence of the band 54 of the previous two 
embodiments. A guard 76 to prevent pinched fingers is preferred in this 
and all embodiments described herein. 
Yet another embodiment operating in the manner of a sewing machine is shown 
in simplified form in FIGS. 12-15. A worktable 78 having a slot 80 therein 
is provided for the support of the materials 10, 20 to be joined. The 
movement and the bonding are accomplished by a pair of opposed contact 
feet 82 having the contact pins 22 extending towards one another on the 
facing surfaces thereof. The contact feet 82 are not in electrical contact 
with one another and, therefore, electrical contact to the pins 22 can be 
in the simple manner of that used with the apparatus of FIG. 11; that is, 
for example, the upper foot 82 can be connected to positive (+) and the 
lower foot 82 connected to negative (-) as indicated. The feet 82 work in 
mirror image of one another and are operably connected to means (not 
shown) for moving them in the manner of the driving foot of a sewing 
machine. Such driving assemblies, again, are well known to those skilled 
in the art and are not shown in the interest of simplicity and to avoid 
redundancy. In their initial position as shown in FIG. 12, the feet 82 are 
separated and forward. As depicted by FIG. 13, the feet 82 then move 
towards one another to grip the materials 10, 20 therebetween and contact 
the adhesive layer. The feet 82 then move to the position of FIG. 14 
(drawing the material 10, 20 with them) during which time the adhesive is 
heated by the current flowing therethrough so as to bond that area of the 
materials 10, 20 together in the manner of a sewing machine taking a 
stitch. The feet 82 then move apart and back to the position of FIG. 12 as 
indicated by the arrows of FIG. 15. The process then repeats for another 
"stitch.