Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
  • B05C5/02—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
  • B05C5/02—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
  • B05C5/0225—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work characterised by flow controlling means, e.g. valves, located proximate the outlet

Definitions

• the present invention relates to a spreading head, particularly for spreading thermoplastic material on an intermediate component.
• Known spreading heads are currently used which are usually arranged transversely to the direction of movement of the intermediate component.
• Such heads are usually composed of a laminar-flow assembly having a beak-shaped cross-section, an upper clamp block, and an underlying lower clamp block.
• thermoplastic material for example adhesives, including those known as “hot melt” or “reactive hot melt” adhesives
• a suitable continuous melting unit for example adhesives, including those known as “hot melt” or “reactive hot melt” adhesives
• a drum unloader is then injected into the spreading head by means of gear pumps.
• the transverse distribution of the adhesive is performed by means of a closed duct affected by uniformly spaced valves (modules), which allow the adhesive to reach a second laminar-flow region through channels and optionally a third region.
• Such channels convey the adhesive directly to the laminar-flow assembly, which is directly connected to the intermediate component.
• valves usually known as modules, which are mostly actuated by electric valves of the pneumatic or magnetic type.
• the duct is closed downstream of each valve by means of a device of the needle type, which closes onto an appropriately provided cup.
• the ducts are opened by lifting the needle from the closed position.
• the main drawback of this known head is the fact that sometimes the opening movement of the valve is not achieved; this can depend on various situations, including the fact that the injected hot-melt adhesives can be unstable and, if they remain at high temperature, can trigger charring (cracking) phenomena that block the valve. Furthermore, if reactive hot-melts are used, the adhesive can polymerize in the head itself, consequently blocking the valve.
• the opening movement of the valve might not be achieved also due to normal mechanical problems (hindered sliding movements) or due to wear or failure of sealing gaskets (O-rings) of the pneumatic circuit.
• the uncontrolled failure of a valve to open entails a severe damage for the application of the adhesive and entails, in the case of spreading heads of the known type, a reduction in the overall amount of adhesive applied to the substrate.
• heads of the so-called “step” type (which comprise multiple regions for releasing the material in film form) are much more severe: such heads are choked transversely and each individual valve supplies a step without thereby any possibility to compensate for the adhesive that does not arrive from the unintentionally "closed” valve; the occurrence of this condition entails the uncontrolled production of rejects, since a band as wide as the step of adhesive will be missing on the strip being processed.
• the aim of the present invention is therefore to solve the noted technical problems, eliminating the drawbacks of the cited known art and thus providing an invention that allows to obtain a head that allows to monitor the actual open condition of the valves (modules).
• an object of the present invention is to provide a spreading head in which it is possible to detect the position of the needle in the valve, preferably detecting that it is in the open position. Another important object is to provide a spreading head in which it is possible to detect immediately any failure to apply adhesive on a band.
• Another object is to provide a spreading head that is structurally simple and has low manufacturing costs.
• a spreading head particularly for spreading thermoplastic material on an intermediate component, comprising a first duct for feeding an adhesive to a valve provided with a needle that interferes with a cup connected to a second duct for spreading said adhesive, characterized in that said valve comprises means suitable to actuate and/or visualize a selective positioning of said needle.
• Figure 1 is a side view of the spreading head according to the present invention
• Figure 2 is a partially sectional view, similar to Figure 1;
• Figure 3 is a sectional view of the valve
• Figure 4 is a view, similar to Figure 3, of the valve
• Figure 5 is a view of the use of a capacitive sensor with the valve in the closed condition
• Figure 6 is a view of the embodiment of Figure 5, with the valve in the open condition.
• the reference numeral 1 designates a spreading head particularly for spreading thermoplastic material on intermediate components.
• the head 1 is preferably arranged transversely to the flow of motion of intermediate components on which for example an adhesive is to be applied, and has a first duct 2 for feeding the adhesive at a hole 3 for the transverse distribution of the adhesive at one or more valves 4.
• Each one of the valves 4 comprises a body 5, rigidly coupled to the head
• valve 4 there are means suitable to actuate the selective positioning of the needle 6 in an open position, such means being constituted for example by a first air intake 11 obtained laterally from the body 5 and connected to a third duct 12, which is in turn connected to a chamber 13 provided between a rear end 14 of the body 5 directed away from the cup 8 and a disk 15 to which a rear end 16 of the needle 6 is axially coupled, the disk sliding at a cover 17, which is associated with the rear end 14 of the body 5.
• a first air intake 11 obtained laterally from the body 5 and connected to a third duct 12, which is in turn connected to a chamber 13 provided between a rear end 14 of the body 5 directed away from the cup 8 and a disk 15 to which a rear end 16 of the needle 6 is axially coupled, the disk sliding at a cover 17, which is associated with the rear end 14 of the body 5.
• the disk 15, and therefore the needle 6, can move axially with respect to the body 5 and the cover 17 in contrast with at least one elastically deformable element, such as a spring 18.
• the free end of the cover 17 advantageously has a second intake 19, which is preferably suitable to be connected to an air supply, like the first intake 11.
• This solution allows to move the needle 6, for example by pneumatic actuation: it is possible to inject air at the first intake 11, so as to force the uncoupling of the tip 7 of the needle 6 from the cup 8, thus connecting the hole 3 to the second duct 9, so as to allow to spread the adhesive.
• Any injection of air at the second intake 19 instead allows to achieve the movement of the needle 6 until it is arranged in the closed condition, in which its tip 7 closes the end of the second duct 9, so as to prevent the spreading of the adhesive.
• the step for closing the needle 6 can be achieved by setting the spring 18 appropriately.
• a fifth intake 26 which is formed laterally to the body 5 at the chamber 13: at the fifth intake 26 it is possible to arrange an additional pressure sensor or a sensor for detecting the position of the disk 15 connected to the needle 6.
• an appropriate pressure sensor 20 which is suitable to confirm the position of the disk 15 and therefore of the needle 6, for example in the open condition in which the tip 7 of the needle does not close the second duct 9.
• a third air intake 21 As an alternative, as shown in Figure 4, laterally to the cover 17 there is a third air intake 21, and at the same time the second intake 19 is closed by means of a capacitive sensor 22, suitable to provide a signal indicating the correct placement of the disk 15 and therefore of the needle 6.
• the capacitive sensor 22 can be of the ON/OFF type if one wishes to detect exclusively the correct opening of the needle 6, or of the proportional type if one wishes to check, by means of the same instrument, also the correct closure of the needle 6.
• the spring 18 might be omitted.
• a sensor suitable to check the position assumed by the needle 6 inside the body 5 for example a suitable optical sensor, which can be arranged at a fourth intake 23 formed radially with respect to the body 5 and adapted to connect an outer lateral surface 24 thereof with the seat in which the needle 6 slides.
• the correct closed or open position of the needle 6 can be detected once again.
• an electric position sensor which can also be positioned, for example, at the second intake 19.
• a pressure sensor in the adhesive circuit located downstream of the valve 4 and therefore at the second duct 9; such duct can in fact be connected, by means of a suitable fourth duct 25, to the outside of the head 1; the fourth duct 25 is connected to a suitable pressure sensor 20 for hot-melt, which reports the correct opening of the valve because the pressure of the adhesive circuit downstream of said sensor has been reached.
• Figures 5 and 6 illustrate the use of a capacitive sensor 22 in combination with the third intake 21 for the inflow of, for example, air, so as to allow the axial closure movement of the needle 6.
• the cover 17 is elongated in order to allow to accommodate the capacitive sensor 22, which has a suitable axial length.
• the capacitive sensor 22 can be used to check both the closed state and the open state (of the end of the second duct 9) of the needle 6; in the first case, the capacitive sensor 22 can therefore check the closure movement of the needle 6; advantageously, there is a suitable amplifier for the signal that arrives from the capacitor sensor 22 and there is a visual indicator 27, which comprises two LEDs 28a and 28b suitable, for example, to visually indicate the state of the position of the needle 6 and therefore the closure or not of the end of the second duct 9.

Landscapes

• Coating Apparatus (AREA)
• Slide Fasteners, Snap Fasteners, And Hook Fasteners (AREA)
• Materials For Medical Uses (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (2)

Family

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Family Applications (1)

Country Status (10)

Families Citing this family (11)

Family Cites Families (10)

• 2001
  • 2001-01-17 IT IT2001TV000008A patent/ITTV20010008A1/it unknown
• 2002
  • 2002-01-10 CN CNB02803712XA patent/CN1225316C/zh not_active Expired - Fee Related
  • 2002-01-10 WO PCT/EP2002/000170 patent/WO2002057025A2/en not_active Ceased
  • 2002-01-10 US US10/250,747 patent/US6983860B2/en not_active Expired - Lifetime
  • 2002-01-10 AT AT02715408T patent/ATE307680T1/de not_active IP Right Cessation
  • 2002-01-10 AU AU2002224989A patent/AU2002224989A1/en not_active Abandoned
  • 2002-01-10 ES ES02715408T patent/ES2251581T3/es not_active Expired - Lifetime
  • 2002-01-10 JP JP2002557527A patent/JP3943025B2/ja not_active Expired - Fee Related
  • 2002-01-10 EP EP02715408A patent/EP1355743B1/en not_active Expired - Lifetime
  • 2002-01-10 DE DE60206877T patent/DE60206877T2/de not_active Expired - Lifetime

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