WO1991006398A1

WO1991006398A1 - Grinding belt

Info

Publication number: WO1991006398A1
Application number: PCT/DK1990/000285
Authority: WO
Inventors: Rolf Barman-Jensen
Original assignee: Barman Jensen Rolf
Priority date: 1989-11-07
Filing date: 1990-11-07
Publication date: 1991-05-16
Also published as: DK553289A; DK553289D0; AU6733590A

Abstract

A grinding belt (1) according to the invention has as base part (2) a through-going belt of woven wire netting of metal, preferably stainless steel onto which carbide grains (3) are soldered. Thus a hard-wearing belt suitable for grinding and rasping semi-hard materials, e.g. within the shoe industry, is obtained, a belt which does not suddenly break down and consequently causes danger to the personnel working at the grinding machine, as the wires of the netting will break or be torn apart one by one, thus giving the operator a chance of stopping the machine before it breaks down. In order to improve the friction properties of the belt (1), the base part can be furnished with a bearing layer (4) of a non-metallic material. The bearing layer (4) may contain glass fibres (5) to improve the tensile rigidity of the belt.

Description

GRINDING BELT

The invention concerns a grinding belt to be used for grinding soft or semi-hard materials, e.g. raw materials for shoes, and comprising a through-going, band-shaped base-part bearing abrasive particles on one side. It is about a grinding belt of the type which sits stretched out as an endless band around one or more runners or driving wheels. It is not necessarily a question of the driving wheels being in direct contact with the abrasive particles; a binding agent or an intermediate layer can form the con¬ nection between particles and base part.

The grinding belts for semi-hard materials known hitherto have mainly consisted of sandpaper belts which are cheap to purchase, but have a short life. Hitherto it has been avoided to apply metal belts or band steel as a base material for manual grinding operations, as the band, in case it breaks during the working operation, makes out a great danger for the operator.

The purpose of the invention is to provide a grinding belt for relatively soft materials which has a considerably longer life and therefore demands fewer exchanges than the known grinding belts, and which at the same time will not suddenly split during operation and become a safety risk to the surroundings.

According to the invention this is obtained by a grinding belt where the base part comprises a wire netting of metal coated with abrasive particles by a soldering process.

In case one or more wires of the base part break or are torn apart the grinding belt as such will still be intact, and the operation can proceed or the operator has time enough to stop the machine and replace the grinding belt before a break down occurs. At the same time a very strong grinding belt with a great abrasive capacity is obtained, with which materials with a great hardness can be ground or grated. The soldering process can e.g. consist in a process of the known art applying a binding agent in the form of a copper alloy. Although a grinding belt according to the in¬ vention is essentially more expensive to manufacture than a sandpaper belt, this fact will be more than counterbalanced by the considerably lower maintenance costs due to the much fewer replacements of the belts of the machine.

From publication DE A1 32 36 134 there is known a grinding tool to be used for grinding and burring metallic materials which in the nature of the case possess a great hardness. For this special purpose a grinding medium bearer for the tool can be made of metal wires which are coated with abrasive particles by electrolysis and next are woven to form a bearer of a grinding medium. The particles can be of diamond, boron nitride or corundum and they are embedded into a hard-metallic layer by the electrolysis. As the belt is worn the particles are gradually laid free, which is of importance for obtaining a sufficient life for the grinding tool when relatively hard materials are ground. To put a particle coating on the wires before the weaving is, however, a more expensive process than that employed accor¬ ding to the invention, likewise an electrolytic process is considerably more expensive than a soldering process. So is the known grinding medium basis by virtue of its structure so expensive to manufacture that it is not profitable for grinding rather soft materials.

As indicated in claim 2 it is preferred that the wires of the netting are made of stainless steel. Further carbide grains are preferred as abrasive particles as it has been mentioned in claim 3. In order to improve the grinding belt's running, wearing and friction characteristics the metal netting, as mentioned in claim 4, can be fitted with a non-metallic layer of material with adequate properties.

As indicated in claim 5 the non-metallic material layer can contain glass fibres, either in a special layer or mixed with a thermoplastic layer, by which the mechanical properties of the belt will be improved, e.g. by orientating the fibres in the longitudinal direction of the belt which implies an increased tensile stiffness and breaking strength of the belt.

A preferred form of embodiment of the invention will be de- scribed in more details in the following with reference to the drawing which shows a section through a grinding belt according to the invention.

A grinding belt 1 according to the invention is built up of a base part 2 with abrasive particles 3 and a bearing layer 4 which contains glass fibres 5 orientated in the longi¬ tudinal direction of the belt in a matrix of polyamide, which has a great wearability and an adequate friction co¬ efficient in proportion to the runners and drive wheels of steel on which the belt 1 is to run. Alternatively a bearing layer of glass-coated tape such as Scotch no. 365 TM, which has a layer of thermo-hardenmg gum-resin on one side for adherence onto the base part 2, is applicable.

The base part 2 is a woven net of wires of stainless steel and it is made by cutting it out of commercially available materials to form belts of the suitable lengths. After de- greasing, this belt is conducted through a production line where first its grinding surface 6 is coated with glue and next with wolfram carbide particles 3. After that glue is put on again and finally a soldering material, viz. a powdered copper solder consisting of nearly pure copper (99,9%). The types of glue applied here can be various com¬ monly known and commercially available sorts, e.g. cyano acrylate glue. A faintly sticking glue of the brand ϋϋnniiffiixx T TMM,, aallssoo uusseedd eas a remedy within the textile in- dustry, is preferred.

The soldering takes place in a transition furnace, e.g. of the brand Remington TM which is known to the skilled in the art, where the belt passes various temperature zones in a protective gas, preferably hydrogen: a preheating zone, a soldering zone and a cooling zone. In the preheating zone the temperature is brought up to about 6oo°C in the course of five minutes and the soldering takes place during the passage of the soldering zone in five minutes at a tempera¬ ture between 1050 and 1150°C, preferably 1080°C.

During the heating the glue will decompose and vaporize, as it has only served to an interim fixation of the carbide grains and the powdered solder respectively. In the cooling zone the temperature is stepped down through four part- zzoonneess wwiitthh 5500 CC ppeerr ppaarrtt--zzoonnee.. AAfftteerr ttlhis the belt is air- cooled down to the ambient temperature.

The soldering method described above is a variant of soldering method of the known art and other copper- or nickel-based solders can be used; likewise soldering tem¬ peratures between 850 C and 1150 C are applicable.

After the soldering the belt is cut into certain lengths with 45° cutting angle at the ends which are joined to form a continuous belt by overlapping and spot-welding the ends. Alternatively, other known methods for joining the belt can be used, such as glueing or splicing the wire netting.

The base part 2 and the bearing layer 4 can be joined by glueing or, if the bearing layer 4 as described above main¬ ly consists of a thermoplastic, by heating the plastic and next joining the parts 2 and 4. When a glass-coated tape as mentioned above is used the attachment is performed by heating the joint of base part 2 and bearing layer 4 up to approx. 160 C.

Within the stipulations of the claims the grinding belt ac¬ cording to the invention of course can be carried out otherwise than described here. E.g. the glass fibres can be replaced by synthetic fibres.

Claims

1. A grinding belt to be used for grinding soft or half- hard materials, for example raw materials for shoes, and comprising a through-going, band-shaped base part bearing abrasive particles on one side, c h a r a c t e r i z e d in that said base part comprises a metal wire netting coated with abrasive articles by a soldering process.

2. Grinding belt according to claim 1, c h a r a c t e r i z e d in that the wire netting is made of stainless steel wires.

3. Grinding belt according to claim 1 or 2, c h a r a c t e r i z e d in that the abrasive particles are carbide grains.

4. Grinding belt according to claims 1 to 3, c h a r a c t e r i z e d in that the wire netting on its side opposite the abrasive particles is furnished with a non-metallic layer of material.

5. Grinding belt according to claim 4, c h a r a c t e r i z e d i n that the non-metallic layer of material contains glass-fibres.