Process for joining abutting thermoplastic synthetic-resin foam sheets

© Start of patent duration: Longest possible duration:

© Issued on:

© inventor:

SIEGBURG

TROISDORF

1979 03 15

1979 10 25

ALFTER FRANZ WERNER ING · FEDERAL REPUBLIC

BREITSCHEIDEL HANS-ULRICH FEDERAL REPUBLIC

GERMANY

ING.

GERMANY © Dependence:

352 997 © Pamphlets considered to delineate the prior art:

AT-PS 310429 CH-PS 368603 US-PS3537941

- 2 No. 352997

The invention relates to a method for joining abutting sheets of thermoplastic foam, for example teilvemetztem polyethylene foam, wherein a joint covering the band is applied.

Furthermore, the invention relates to a device for continuously carrying out the method with ⁵ a holder and a support roll rotatably mounted on the support for the metal foil strip and a rotatably mounted on the holder with a pair of fork arm pressure roller.

A method or apparatus that is similar are known from U.S. Patent No. 3,537,941.

The joining of foam sheets is required, for example, on construction sites where foam¹⁰ Fabric panels are used eg for roofing.

A structurally good flat roof cover consists of several layers of different materials, each of which has to fulfill a specific task. For some of these layers are very well plastic foam tracks, for example made of soft PVC, polystyrene, polyurethane or teilvemetztem polyethylene. An on-site to be performed connecting such foam sheets requires¹⁵ particularly easy-to-use devices and simple procedures that are less susceptible to interference

Largely eliminate errors.

The object of the invention is to find a method and a device that meets these conditions.

The inventive method of the type mentioned is characterized in that a ²⁰ over the softening or melting temperature of the foam heated metal foil strip with low

Pressure on the joint is pressed.

By pressing on a heated metal strip according to the invention with low pressure on the abutting at the junction foam sheets or plates heat transfer to the foam is achieved and by the associated melting of the foam surface, the metal strip is permanently connected in the joint area. At the same time there is still a partial connection of the

Edges of the foam sheets with each other instead.

The heating of the metal foil can be effected by hot air, by a gas flame or by electric heating.

The sole heating of the metal strip has the advantage that above the softening 3 ° or melting point of the foam lying required temperature of, for example, about 220 ° C in teilvernetztem polyethylene foam, temperature fluctuations, eg due to fluctuations in the welding speed, no effect on the quality of the compound to have. Temperature fluctuations only have the consequence that the metal strip melts a little more or less deep into the foam surface.

As a metal foil strip, an aluminum strip, in a thickness of, for example, 0.1 mm can be used. On the side facing the foam, the metal foil tape can carry a film of a heat-activable adhesion promoter. Appropriately, the same plastic as for the foam sheet is used for the adhesion-promoting film.

A device of the type mentioned for carrying out the method according to the invention is characterized in that a heat source, eg a hot air nozzle, is provided, which is arranged at the lower end of the holder in the feed direction in the area in front of the pressure roller and on which the Metällfolienband is guided past, wherein the pressure roller and an additional, rotatably mounted on the support via a Gabelarmpaar in front of the pressure roller support roller Casters are provided.

Advantageously, the Gabelarmpaare are mounted on the holder in a common pivot point. The supply roll and the support roller may be mounted at the opposite ends of the same Gabelarmpaares, said at one end of the pressure roller bearing fork arm pair is rigidly mounted at its other end about at the middle of Gabelarmpaares arranged articulation point.

Hiebei the heat source (hot air nozzle, gas flame, etc.) is suitably arranged acting on the metal strip at the lower end of the holder in the area near the pressure roller in front. In addition, it is advantageous to rotatably mounted on the pressure roller bearing fork arm pair still a leadership role that holds the angle of attack of the metal strip on the foam sheets constant.

- 3 No. 352997

The invention is explained in the drawing of an embodiment.

The foam sheets or plates -1, 2- are at the joint -3- with the joint covering the metal band -4- ally. The device for establishing the connection is a

Handset with a central holder -11-- and a handle -12-. On the bracket -11- is in⁵ lower area provided a hexagonal sleeve to which a Gabelarmpaar -10- is attached. On Gabelarmpaar -10- are at the top of a supply roll -5- with the metal band --4-- and at the bottom of a support roller -9- stored. At an articulation point --14-- runs with the Gabelarmpaar -10- another Gabelarmpaar -13- together, on which a pressure roller -6- is rotatably mounted. In addition, a guide roller -8- is provided in front of the pressure roller -6- on the Gabelarmpaar -13- io, which leads the metal strip -4- to keep the starting angle on the foam surface constant. The support roller -9-- and the pressure roller -6- serve as rollers of the device. At the lower end of the holder -11- the heat source -7-, for example, a hot air nozzle, attached. The heat source acts in the region of the emergence of the metal strip -4- on the pressure roller -6- on the same. The

Power supply -15- is done through the inside of the handle -12--.

To connect the foam webs -1, 2- the metal strip -4- is guided over the joint -3-. The metal strip -4-- runs off the supply roll -5-, past the guide roll --8-, is heated in front of the pressure roller -6- by the heat source -7- eg of a hot-air nozzle, and heated by the pressure roller -6- on the joint -3- of the foam sheets pressed on. The foam surface melts by heat transfer and it creates a permanent bond in²⁰ continuous operation, which can be performed anywhere with the device according to the invention described.

The method according to the invention avoids the adhesive which is visible in the case of adhesive joints in the area of ​​the joints of the foam webs. Adhesive bonds are undesirable in the high stresses to which the foam sheets are exposed, for example in construction technology due to weather-related temperature changes.