WO1986006671A1 - Abrasive belt with bonded splice - Google Patents

Abrasive belt with bonded splice Download PDF

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Publication number
WO1986006671A1
WO1986006671A1 PCT/EP1985/000221 EP8500221W WO8606671A1 WO 1986006671 A1 WO1986006671 A1 WO 1986006671A1 EP 8500221 W EP8500221 W EP 8500221W WO 8606671 A1 WO8606671 A1 WO 8606671A1
Authority
WO
WIPO (PCT)
Prior art keywords
belt
fibers
synthetic resin
tangled
sanding
Prior art date
Application number
PCT/EP1985/000221
Other languages
German (de)
French (fr)
Inventor
Eberhard TOILLIÉ
Original Assignee
Norddeutsche Schleifmittel-Industrie Christiansen
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to EP84113528A priority Critical patent/EP0142140A3/en
Application filed by Norddeutsche Schleifmittel-Industrie Christiansen filed Critical Norddeutsche Schleifmittel-Industrie Christiansen
Priority to PCT/EP1985/000221 priority patent/WO1986006671A1/en
Publication of WO1986006671A1 publication Critical patent/WO1986006671A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
    • F16G3/00—Belt fastenings, e.g. for conveyor belts
    • F16G3/10—Joining belts by sewing, sticking, vulcanising, or the like; Constructional adaptations of the belt ends for this purpose
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
    • B24D11/06—Connecting the ends of materials, e.g. for making abrasive belts

Definitions

  • the invention relates to an abrasive belt with a connection point formed by two ends of the abrasive belt, which is bridged by a connecting belt which is glued overlapping to the ends of the abrasive belt and which contains reinforcing fibers which are tangled in a synthetic resin matrix.
  • US-A 3154897 shows an abrasive belt of the type mentioned, in which the connection point is bridged with a prefabricated connecting belt.
  • the connecting belt consists of a laminate of a layer of rectified fibers on the side of the belt facing the sanding belt and a layer formed by a mat of fibers arranged on the other side of the belt, which is covered with a partially polymerized synthetic resin ⁇ are soaked.
  • This tape is on the junction placed and connected to the ends of the abrasive belt under the application of heat and pressure, the synthetic resin polymerizing out.
  • the Germans ⁇ take mainly "they are oriented in the longitudinal direction of the abrasive belt.
  • the tangled an ⁇ parent fibers in the other laminate layer do not have the task of the bonding strength in abrasive belt longitudinal direction They are not able to do this for the reasons given below. Rather, they are intended to match the mechanical properties of the connecting belt to those of the abrasive belt, in order thereby to form resistances which impair the smooth running of the abrasive belt, " To prevent knots "or” gels "and to prevent fatigue of the oriented fibers transmitting the longitudinal force.
  • the connecting belt is on its side facing the grinding belt completely is constantly formed by the layer of fibers oriented in the longitudinal direction of the grinding belt, so that the other layer is shielded from the longitudinal forces. Only when the fibers oriented in the longitudinal direction stretch can a portion of the longitudinal forces be transferred to the outer layer. However, since the fibers in it lie confused and appear to be only short, and therefore the force / elongation ratio of this layer is considerably smaller than that of the longitudinally oriented fibers, especially since these are to be equipped with greater strength, they are longitudinal oriented fibers practically solely responsible for the connection strength. For this reason, the document also emphasizes that these fibers must run in the longitudinal direction of the grinding belt.
  • FR-A 20 57 560 suggests inserting a reinforcing glass fabric into the plastic band formed on the spot from the plastic state, whereby it appears to be exposed that the fibers of the fabric partly in the direction of the abrasive belt connection, partly transversely to this, and consequently in any case obliquely to the tape running direction.
  • This has the disadvantage of reduced strength and higher elongation of the connection.
  • the same document also contains the proposal to mix the plastic applied in the plastic state to form the connecting band into relatively short fibers for reinforcement.
  • such short fibers lack the ability to extend over both ends of the sanding belt and thereby form a direct tension connection.
  • this proposal has the defect that the fibers contained in liquid applied plastic are generally oriented in the direction of application - in this case this can only be the direction of the connecting joint - that is to say deviating from the direction of force transmission, so that their reinforcing effect is low .
  • the invention is therefore based on the object of creating an abrasive belt of the type mentioned at the outset or a connecting belt for connecting the ends thereof, or a method for producing such an abrasive belt connection, which has a high strength regardless of the helix angle of the abrasive belt connection and has a low manufacturing rate ⁇ connect wall and slight thickening of the connection point.
  • the solution according to the invention consists in that the essentially exclusively tangled fibers have a minimum mean length of the order of magnitude of the width of the connecting belt and are predominantly arranged on its cross-sectional side facing the grinding belt.
  • the invention has recognized that, in the case of known fabric-reinforced synthetic resin tapes, the strength of the fabric, measured in the longitudinal direction of the thread, is generally much higher than is necessary for the connection purposes and as a result of forces on the reinforcing threads due to the synthetic resin material containing them Belt or can be transferred through the adhesive connecting the synthetic resin tape with the back of the sanding belt. This leads to the conclusion that too a significantly smaller number of fibers running in the longitudinal direction of the tape can lead to sufficient reinforcement.
  • the invention also includes the finding that the tangled arrangement of the reinforcing fibers facilitates the transmission of force to that (small) portion of the fibers which run in the longitudinal direction of the sanding belt.
  • each individual fiber is anchored more securely within the matrix surrounding it due to its curvatures and the large number of evenly distributed fiber crossing points than the individual fibers of a straight thread, of which at most the outer fibers (and also often only partially) are a direct bond with the surrounding synthetic resin. Accordingly, each individual reinforcing fiber running in the longitudinal direction of the abrasive belt is involved in the power transmission in a substantially more confused arrangement than in a rectified arrangement. This is also an explanation for the fact that in a tangled fiber arrangement the number of fibers running in the longitudinal direction of the sanding belt does not have to be nearly as large as in the case of a fabric reinforcement in order to achieve sufficient connection strength.
  • the suitability of a reinforcing fiber-reinforced connecting belt for increased force absorption in any direction in the case of sanding belt connections can also be particularly advantageous because grinding belts in general and consequently also their connection points are frequently exposed to forces when grinding curved objects, which do not only run in the longitudinal direction.
  • the suitability of the connecting belts according to the invention is particularly valuable in the case of those abrasive belt connections whose joint is not straight, but rather wavy, serrated or fingered interlocking because the forces to be transmitted through the bridging connecting band can be directed differently depending on the local direction of the joint.
  • synthetic resin is to be understood as any synthetic, polymeric material which is suitable in tape form for force-transmitting joint bridging and for embedding fiber material.
  • polyesters, polyamides and polyimides are primarily suitable.
  • Glass, carbon and high-strength synthetic resins such as aramid are particularly suitable as fiber material, but also mineral and metallic fibers.
  • the feature that their mean minimum length should be of the order of magnitude of the width of the connecting band should be interpreted in such a way that it does not should be less than about half the bandwidth. It is preferably between 10 and 80 mm, more preferably between 15 and 40 mm.
  • the titer is expediently between 2 and 80 ⁇ + ex chosen.
  • the choice of fiber lengths and thicknesses is of course also up to a certain point. Depends on the thickness of the tape used, which is advantageously between 0.025 mm and 0.35 mm.
  • the arrangement of the fibers in the connecting belt predominantly on its cross-sectional side facing the grinding belt has the advantage that the connecting forces have to be transmitted in the form of shear stresses over a smaller thickness range of the synthetic resin belt. This gives greater security and less stretch.
  • the reinforcing fibers can be at least partially exposed on the surface of the connecting belt facing the grinding belt. As a result, the strength of the connection of the connecting belt with a binder layer located between the latter and the back of the grinding belt can be improved. In this connection, a layered structure of the connecting band is appropriate.
  • the adhesives which have been tried and tested in the prior art can be used to glue the connecting belt to the adjacent edges of the abrasive belt ends to be connected.
  • the prefabricated connecting belt in the uncured state can also be pressed onto the grinding belt, which may be provided with an adhesive or adhesive, and left to harden.
  • synthetic resin that is not or only partially polymerized can be used. If a thermoplastic material is used, it can also be applied in a molten state. If the synthetic resin belt is built up in layers, there is also the possibility that the uncured state when applying the belt only relates to the layer facing the grinding belt.
  • a particular advantage of applying the synthetic resin in the plastic state is that an intimate connection can be achieved with the back of the abrasive belt, possibly without additional layers of binder, and possibly a cross-sectional shaping of the connecting belt can take place. 6
  • the connecting belt on the back of the sanding belt is that it is built up in layers on the sanding belt by at least partially pressing a random nonwoven into an initially applied plastic synthetic resin layer, after which the synthetic resin layer is allowed to harden.
  • One or more additional layers can be applied.
  • the synthetic resin can also be pressed in exclusively from the back of the nonwoven, the first synthetic resin layer then being omitted and possibly being replaced by an adhesion promoter or the like.
  • the fibers can be preformed in a fleece shape or sprinkled loose.
  • 1 is a perspective view of an endless grinding belt
  • Fig. 4 shows a longitudinal section through a
  • FIG. 5 shows a plan view of a connecting tape reinforced with random fibers
  • FIG. 6 shows a cross section through a connecting band and 7 and 8 longitudinal sections through different
  • the connection point 3 runs obliquely at an angle 4 with respect to the transverse direction of the grinding belt.
  • the joint 7 of the connection point can run in a straight line or not in a straight line; 3 shows a wave cut connection.
  • the sanding belt consists of the tensile, flexible base 5 and the abrasive grain covering 6. At 7, the joint between the belt ends to be connected can be seen. The connection is mediated by the connecting band 8, which is connected to the adjacent edges 9 of the back of the grinding belt, for example for gluing.
  • the connecting band 8 contains the reinforcing fibers 11, according to the plan view in FIG. 5, evenly distributed, while in the cross section according to FIG. 6 they are contained in a higher concentration, in particular in layer form, in the vicinity of the surface 12 of the connecting band 8 which is intended for gluing to the back of the sanding belt 1. Their length is in the order of the connection bandwidth 10.
  • the reinforcing fibers 11 are preferably oriented predominantly parallel to the plane of the connecting band, which can be produced, for example, by stretching the band after casting in the longitudinal and / or transverse direction or by introducing the fibers as a pre-formed nonwoven.
  • the fibers 11 according to FIG. 7 protrude beyond the surface 12 or are at least partially free of it, they can form an intimate connection with the binder layer 13, which in the example shown is between the back of the sanding belt base 5 and the connecting belt 8 is provided.
  • the connecting belt 14 is molded into the depression which was formed by wedge-shaped beveling of the edges 15 of the abrasive belt ends to be connected.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Polishing Bodies And Polishing Tools (AREA)

Abstract

An abrasive belt with a splice which is overlapped by a synthetic resin strip (8) which contains reinforcing fibers (11). A good longitudinal strength is achieved, despite the small amount and limited thickness of the synthetic resin strip, by the use of tangled fibers (11) which are located close to the surface (12) of the synthetic resin strip (8) which is connected to the abrasive belt (1).

Description

" / " /
Schleifband mit einer verklebten VerbindungsstelleSanding belt with a glued connection point
Beschreibungdescription
Die Erfindung bezieht sich auf ein Schleifband mit einer von zwei Schleifbandenden gebildeten Verbindungsstelle, die durch ein überlappend mit den Schleifbandenden ver¬ klebtes Verbindungsband überbrückt ist, das in einer Kunstharzmatrix wirr orientierte Verstärkungsfasern ent¬ hält.The invention relates to an abrasive belt with a connection point formed by two ends of the abrasive belt, which is bridged by a connecting belt which is glued overlapping to the ends of the abrasive belt and which contains reinforcing fibers which are tangled in a synthetic resin matrix.
Die US-A 3154897 zeigt ein Schleifband der genannten Art,- bei dem die Verbindungsstelle mit einem vorgefertigten Verbindungsband überbrückt ist. Das Verbindungsband be¬ steht aus einem Laminat von einer Schicht aus gleichge¬ richteten Fasern auf der dem Schleifband zugewendeten Sei¬ te des Bandes und einer von einer Matte wirr angeordneter Fasern gebildeten Schicht auf der anderen Seite des Bandes, die mit einem teilweise polymerisierten Kunstharz durch¬ tränkt sind. Dieses Band wird auf die Verbindungsstelle gelegt und unter Wärmezufuhr und Druck mit den Schleif¬ bandenden verbunden, wobei das Kunstharz auspolymerisiert. Da die gleichgerichteten Fasern auf der dem Schleifband zugewendeten Seite des Verbindungsbandes die Verbindungs¬ kräfte hauptsächlich aufzunehmen haben, sind"sie in Längsrichtung des Schleifbandes orientiert. Die wirr an¬ geordneten Fasern in der anderen Laminatschicht haben nicht die Aufgabe, die Festigkeit der Verbindung in Schleifbandlängsrichtung zu vergrößern; dazu sind sie aus den weiter unten angegebenen Gründen auch nicht in der Lage. Vielmehr sollen sie dazu dienen, die mechanischen Eigenschaften des Verbindungsbandes denen des Schleifban¬ des anzugleichen, um dadurch die Bildung von den glatten Lauf des Schleifbandes beeinträchtigenden Widerständen, "Knoten" oder "Geleriken" zu verhindern und die Ermüdung der die Längskraft übertragenden orientierten Fasern zu verhüten. Der Grund dafür, daß sie an der Übertragung der Längskräfte der Verbindung nicht teilhaben, liegt idarin, daß das Verbindungsband auf seiner dem Schleifband zuge¬ wendeten Seite vollständig von der Schicht der in Längs¬ richtung des Schleifbandes orientierten Fasern gebildet ist, so daß die andere Schicht von den Längskräften ab¬ geschirmt ist. Nur wenn die in Längsrichtung orientierten Fasern sich dehnen, kann ein Anteil der Längskräfte auf _ die außen liegende Schicht übertragen werden. Da die Fa¬ sern darin aber wirr liegen und nur kurz zu sein scheinen und da daher das Kraft/Dehnungsverhältnis dieser Schicht wesentlich kleiner ist als dasjenige der längs orierentier- ten Fasern, zumal diese mit größerer Festigkeit ausge¬ stattet werden sollen, sind die längs orientierten Fasern praktisch alleine verantwortlich für die Verbindungsfestigkeit. Deshalb betont die Schrift auch, daß diese Fasern in Längs¬ richtung des Schleifbandes verlaufen müssen. Da man aber für die Bandverbindungsstelle im allgemeinen eine sogenannte Schrägstoßverbindung wählt, bei welcher die Verbindungs¬ fuge nicht rechtwinklig sondern schrägwinklig zur Bahn¬ längsrichtung verläuft, muß, damit die Fasern im Verbin¬ dungsband gleichwohl in Bandlängsrichtung verlaufen, das Verbindungsband aus einem größeren Folienstück schräg ge¬ schnitten werden unter einem Winkel, der der Schrägungs- richtung der Schleifbandverbindung entspricht! Dies ist materialaufwendig und umständlich und demzufolge kost¬ spielig.US-A 3154897 shows an abrasive belt of the type mentioned, in which the connection point is bridged with a prefabricated connecting belt. The connecting belt consists of a laminate of a layer of rectified fibers on the side of the belt facing the sanding belt and a layer formed by a mat of fibers arranged on the other side of the belt, which is covered with a partially polymerized synthetic resin ¬ are soaked. This tape is on the junction placed and connected to the ends of the abrasive belt under the application of heat and pressure, the synthetic resin polymerizing out. Have as the unidirectional fibers on the side facing the abrasive belt side of the connecting band forces the Verbindungs¬ take mainly "they are oriented in the longitudinal direction of the abrasive belt. The tangled an¬ parent fibers in the other laminate layer do not have the task of the bonding strength in abrasive belt longitudinal direction They are not able to do this for the reasons given below. Rather, they are intended to match the mechanical properties of the connecting belt to those of the abrasive belt, in order thereby to form resistances which impair the smooth running of the abrasive belt, " To prevent knots "or" gels "and to prevent fatigue of the oriented fibers transmitting the longitudinal force. The reason why they do not participate in the transmission of the longitudinal forces of the connection is usually that the connecting belt is on its side facing the grinding belt completely is constantly formed by the layer of fibers oriented in the longitudinal direction of the grinding belt, so that the other layer is shielded from the longitudinal forces. Only when the fibers oriented in the longitudinal direction stretch can a portion of the longitudinal forces be transferred to the outer layer. However, since the fibers in it lie confused and appear to be only short, and therefore the force / elongation ratio of this layer is considerably smaller than that of the longitudinally oriented fibers, especially since these are to be equipped with greater strength, they are longitudinal oriented fibers practically solely responsible for the connection strength. For this reason, the document also emphasizes that these fibers must run in the longitudinal direction of the grinding belt. However, since a so-called angled butt joint is generally chosen for the band connection point, in which the connecting joint is not at right angles but at an angle to the longitudinal direction of the web, so that the fibers in the connecting band nevertheless run in the longitudinal direction of the band, the connecting band from a larger piece of film is inclined be cut at an angle that corresponds to the inclined direction of the sanding belt connection! This is material-intensive and cumbersome and consequently expensive.
Die FR-A 20 57 560 schlägt vor, in das aus dem plastischen Zustand an Ort und Stelle geformte Kunststoff¬ band ein verstärkendes Glasgewebe einzulegen, wobei vor¬ ausgesetzt zu sein scheint, daß die Fasern des Gewebes teils in Richtung der Schleifbandverbindung, teils quer zu dieser, und demzufolge in jedem Falle schräg zur Band¬ laufrichtung orientiert sind. Dies hat den Nachteil re¬ duzierter Festigkeit und höherer Dehnung der Verbindung. - Dieselbe Schrift enthält auch den Vorschlag, den im plastischen Zustand zur Bildung des Verbindungsbandes aufgebrachten Kunststoff in relativ kurze Fasern zwecks Verstärkung einzumischen. Jedoch fehlt derartigen kurzen Fasern die Möglichkeit, sich über beide Schleifbandenden zu erstrecken und dadurch eine direkte SpannungsVerbindung zu bilden. Außerdem haftet diesem Vorschlag der Mangel an, daß die in flüssig aufgetragenem Kunststoff enthaltenen Fasern im allgemeinen in Aufbringungsrichtung - das kann in diesem Fall nur die Richtung der Verbindungsfuge sein - orientiert sind, also abweichend von der Kraftübertragungs- richtung, so daß ihr Verstärkungseffekt gering ist. Der Erfindung liegt daher die Aufgabe zugrunde, ein Schleif- band der eingangs genannten Art bzw. ein Verbindungsband zum Verbinden von dessen Enden bzw. ein Verfahren zum Herstellen einer solchen Schleifbandverbindung zu schaf¬ fen, die hohe Festigkeit unabhängig vom Schrägungswinkel der Schleifbandverbindung mit geringem Herstellungsauf¬ wand und geringer Verdickung der Verbindungsstelle ver¬ binden.FR-A 20 57 560 suggests inserting a reinforcing glass fabric into the plastic band formed on the spot from the plastic state, whereby it appears to be exposed that the fibers of the fabric partly in the direction of the abrasive belt connection, partly transversely to this, and consequently in any case obliquely to the tape running direction. This has the disadvantage of reduced strength and higher elongation of the connection. - The same document also contains the proposal to mix the plastic applied in the plastic state to form the connecting band into relatively short fibers for reinforcement. However, such short fibers lack the ability to extend over both ends of the sanding belt and thereby form a direct tension connection. In addition, this proposal has the defect that the fibers contained in liquid applied plastic are generally oriented in the direction of application - in this case this can only be the direction of the connecting joint - that is to say deviating from the direction of force transmission, so that their reinforcing effect is low . The invention is therefore based on the object of creating an abrasive belt of the type mentioned at the outset or a connecting belt for connecting the ends thereof, or a method for producing such an abrasive belt connection, which has a high strength regardless of the helix angle of the abrasive belt connection and has a low manufacturing rate ¬ connect wall and slight thickening of the connection point.
Die erfindungsgemäße Lösung besteht darin, daß die im wesentlichen ausschließlich wirr orientierten Fasern eine mindeste mittlere Länge von der Größenordnung der Breite des Verbindungsbands aufweisen und überwiegend auf dessen dem Schleifband zugewendeten Querschnittsseite angeordnet sind.The solution according to the invention consists in that the essentially exclusively tangled fibers have a minimum mean length of the order of magnitude of the width of the connecting belt and are predominantly arranged on its cross-sectional side facing the grinding belt.
Auf den ersten Blick scheint die Lösung in Gegensatz zu stehen zu der Erfahrung, daß bei einer Gewebeverstärkung mit winklig zur Schleifbandlängsrichtung verlaufenden Fä¬ den keine hinreichenden Festigkeiten und Dehnungswerte erreicht werden, denn auch bei wirrer Anordnung der Ver¬ stärkungsfasern ist damit zu rechnen, daß der größte Teil der Fasern winklig zur Schleifbandlängsrichtung verläuft. Jedoch hat die Erfindung erkannt, daß bei bekannten gewebe¬ verstärkten Kunstharzbändern die Festigkeit des Gewebes, in Fadenlängsrichtunq gemessen, im allgemeinen wesentlich höher ist als dies für die Verbindungszwecke erforderlich ist und als an Kräften auf die verstärkenden Fäden durch das sie ent¬ haltende Kunstharzmaterial des Bandes bzw. durch den das Kunstharzband mit der Schleifbandrückseite verbindenden Kleber übertragen werden kann. Dies führt zu dem Schluß, daß auch eine wesentlich geringere Anzahl von in Bandlängsrichtung verlaufenden Fasern zu einer hinreichenden Verstärkung führen kann. - Ferner beinhaltet die Erfindung die Erkennt¬ nis, daß die wirre Anordnung der Verstärkungsfasern die Kraftübertragung auf denjenigen (an sich kleinen) Anteil der Fasern erleichtert, die in Schleifbandlängsrichtung verlaufen. Bei einer Wirrfaseranordnung ist nämlich jede einzelne Faser innerhalb der sie umgebenden Matrix infolge ihrer Krümmungen und der Vielzahl gleichmäßig verteilter Faserkreuzungspunkte sicherer verankert als die einzelnen Fasern eines gerade durchlaufenden Fadens, von dem höchstens die außenliegenden Fasern (und auch diese oft nur teilweise) einen direkten Verbund mit dem umgebenden Kunstharz aufzu¬ weisen haben. Demzufolge wird jede einzelne in Schleifband¬ längsrichtung verlaufende Verstärkungsfaser bei wirrer An¬ ordnung wesentlich stärker an der Kraftübertragung beteiligt als in einer gleichgerichteten Anordnung. Auch dies ist eine Erklärung dafür, daß bei einer Wirrfaseranordnung'die Zahl der in Schleifbandlängsrichtung verlaufenden Fasern zur Er¬ reichung hinreichender Verbindungsfestigkeit bei weitem nicht so groß zu sein braucht wie im Falle einer Gewebe¬ verstärkung. - Schließlich kann die Eignung eines wirrfaser¬ verstärkten Verbindungsbandes zur erhöhten Kraftaufnahme in jeder beliebigen Richtung bei Schleifbandverbindungen auch deshalb besonders vorteilhaft sein, weil Schleifbänder allgemein und demzufolge auch deren Verbindungsstellen beim Schleifen gewölbter Gegenstände häufig Kräften ausgesetzt werden, die nicht nur in Längsrichtung verlaufen. - Besonders wertvoll ist die Eignung der erfindungsgemäßen Verbindungs¬ bändern bei solchen Schleifbandverbindungen, deren Fuge nicht gerade, sondern wellenförmig, gezackt oder gefingert ineinandergreifend verläuft, weil bei diesen die durch das überbrückende Verbindungsband zu übertragenden .Kräfte je nach örtlicher Richtung der Fuge unterschiedlich gerichtet sein können.At first glance, the solution seems to be in contrast to the experience that with a fabric reinforcement with threads running at an angle to the longitudinal direction of the sanding belt, adequate strengths and elongation values are not achieved, because even with a tangled arrangement of the reinforcing fibers, it can be expected that most of the fibers run at an angle to the longitudinal direction of the sanding belt. However, the invention has recognized that, in the case of known fabric-reinforced synthetic resin tapes, the strength of the fabric, measured in the longitudinal direction of the thread, is generally much higher than is necessary for the connection purposes and as a result of forces on the reinforcing threads due to the synthetic resin material containing them Belt or can be transferred through the adhesive connecting the synthetic resin tape with the back of the sanding belt. This leads to the conclusion that too a significantly smaller number of fibers running in the longitudinal direction of the tape can lead to sufficient reinforcement. The invention also includes the finding that the tangled arrangement of the reinforcing fibers facilitates the transmission of force to that (small) portion of the fibers which run in the longitudinal direction of the sanding belt. In a tangled fiber arrangement, each individual fiber is anchored more securely within the matrix surrounding it due to its curvatures and the large number of evenly distributed fiber crossing points than the individual fibers of a straight thread, of which at most the outer fibers (and also often only partially) are a direct bond with the surrounding synthetic resin. Accordingly, each individual reinforcing fiber running in the longitudinal direction of the abrasive belt is involved in the power transmission in a substantially more confused arrangement than in a rectified arrangement. This is also an explanation for the fact that in a tangled fiber arrangement the number of fibers running in the longitudinal direction of the sanding belt does not have to be nearly as large as in the case of a fabric reinforcement in order to achieve sufficient connection strength. - Finally, the suitability of a reinforcing fiber-reinforced connecting belt for increased force absorption in any direction in the case of sanding belt connections can also be particularly advantageous because grinding belts in general and consequently also their connection points are frequently exposed to forces when grinding curved objects, which do not only run in the longitudinal direction. The suitability of the connecting belts according to the invention is particularly valuable in the case of those abrasive belt connections whose joint is not straight, but rather wavy, serrated or fingered interlocking because the forces to be transmitted through the bridging connecting band can be directed differently depending on the local direction of the joint.
Unter Kunstharz ist im Zusammenhang der Verbindung jeder synthe¬ tische, polymere Werkstoff zu verstehen, der sich in Bandform zur kraftübertragenden Fugenüberbrückung sowie zur Einbettung von Fasermaterial eignet. In erster Linie kommen beispielsweise Polyester, Polyamide und Polyimide in Frage. Als Fasermaterial eignen sich vornehmlich Glas, Kohlenstoff und hochfeste Kunst¬ harze wie Aramid, aber auch mineralische und metallische Fasern Das Merkmal, daß ihre mittlere Mindestlänge in der Größenord¬ nung der Breite des Verbindungsbandes liegen soll, ist so aus¬ zulegen, daß sie nicht kleiner als etwa die halbe Bandbreite sein soll. Vorzugsweise liegt sie zwischen 10 und 80 mm, weiter vorzugsweise zwischen 15 und 40 mm. Der Titer wird zweckmäßigerweise zwischen 2
Figure imgf000008_0001
und 80 ά+ex gewählt. Die Wahl der Faserlängen und -dicken ist selbstverständlich auch bis zu einem gewissen . Grade von der Dicke der ver¬ wendeten Bandfolie abhängig, die zweckmäßigerweise zwischen 0,025 mm und 0,35 mm liegt.In the context of the connection, synthetic resin is to be understood as any synthetic, polymeric material which is suitable in tape form for force-transmitting joint bridging and for embedding fiber material. For example, polyesters, polyamides and polyimides are primarily suitable. Glass, carbon and high-strength synthetic resins such as aramid are particularly suitable as fiber material, but also mineral and metallic fibers. The feature that their mean minimum length should be of the order of magnitude of the width of the connecting band should be interpreted in such a way that it does not should be less than about half the bandwidth. It is preferably between 10 and 80 mm, more preferably between 15 and 40 mm. The titer is expediently between 2
Figure imgf000008_0001
and 80 ά + ex chosen. The choice of fiber lengths and thicknesses is of course also up to a certain point. Depends on the thickness of the tape used, which is advantageously between 0.025 mm and 0.35 mm.
Die Anordnung der Fasern in dem Verbindungsband überwiegend auf dessen dem Schleifband zugekehrten Querschnittseite hat den Vorteil, daß die Verbindungskräfte über einen geringeren Dickenbereich des Kunstharzbandes in Form von Schubspannungen übertragen werden müssen. Dies ergibt größere Sicherheit und geringere Dehnung. Nach einem besonderen Merkmal der Erfindung können die Ver¬ stärkungsfasern an der dem Schleifband zugekehrten Ober¬ fläche des Verbindungsbandes wenigstens teilweise frei liegen. Dadurch kann nämlich die Festigkeit der Verbindung des Ver¬ bindungsbandes mit einer zwischen diesem und der Schleifband¬ rückseite befindlichen Bindemittelschicht verbessert werden. In diesem Zusammenhang bietet sich ein schichtförmiger Auf¬ bau des Verbindungsbandes an.The arrangement of the fibers in the connecting belt predominantly on its cross-sectional side facing the grinding belt has the advantage that the connecting forces have to be transmitted in the form of shear stresses over a smaller thickness range of the synthetic resin belt. This gives greater security and less stretch. According to a special feature of the invention, the reinforcing fibers can be at least partially exposed on the surface of the connecting belt facing the grinding belt. As a result, the strength of the connection of the connecting belt with a binder layer located between the latter and the back of the grinding belt can be improved. In this connection, a layered structure of the connecting band is appropriate.
Für die Verklebung des Verbindungsbandes mit den benach¬ barten Rändern der zu verbindenden Schleifbandenden können die im Stand der Technik bewährten Kleber verwendet werden.The adhesives which have been tried and tested in the prior art can be used to glue the connecting belt to the adjacent edges of the abrasive belt ends to be connected.
Alternativ kann auch das vorgefertigte Verbindungsband im nicht ausgehärteten Zustand auf das ggf. mit einem Haftver¬ mittler oder Haftmittel versehene Schleifband aufgepreßt und aushärten gelassen werden. Beispielsweise kann nicht oder nur teilweise polymerisiertes Kunstharz verwendet werden. Es kann bei Verwendung eines thermoplastischen Werkstoffs auch schmelzflüssig aufgetragen werden. Bei schichtweisem Aufbau des Kunstharzbandes besteht auch die Möglichkeit, daß sich der nicht ausgehärtete Zustand beim Auftrag des Bandes nur auf dessen dem Schleifband zugewendete Schicht bezieht. Ein besonderer Vorteil des Auftrags des Kunstharzes im plastischen Zustand besteht darin, daß sich eine innige Verbindung mit der Schleifbandrückseite, ggf. ohne zusätzliche Bindemittelschichten erzielen läßt und ggf. eine Quer¬ schnittsformung des Verbindungsbandes stattfinden kann. 6Alternatively, the prefabricated connecting belt in the uncured state can also be pressed onto the grinding belt, which may be provided with an adhesive or adhesive, and left to harden. For example, synthetic resin that is not or only partially polymerized can be used. If a thermoplastic material is used, it can also be applied in a molten state. If the synthetic resin belt is built up in layers, there is also the possibility that the uncured state when applying the belt only relates to the layer facing the grinding belt. A particular advantage of applying the synthetic resin in the plastic state is that an intimate connection can be achieved with the back of the abrasive belt, possibly without additional layers of binder, and possibly a cross-sectional shaping of the connecting belt can take place. 6
Schließlich besteht eine Möglichkeit zur Aufbringung des Verbindungsbandes auf der Rückseite des Schleifbandes darin, daß es auf dem Schleifband schichtweise aufgebaut wird, indem in eine zunächst aufgetragene, plastische Kunstharzschicht ein Wirrvlies zumindest teilweise ein¬ gepreßt wird, wonach man die Kunstharzschicht erhärten läßt. Es können noch eine oder mehrere weitere Schichten aufgebracht werden. Das Kunstharz kann auch ausschließlich von der Vliesrückseite eingepreßt werden, wobei dann die erste Kunstharzschicht entfällt und ggf. durch einen Haftvermittler oder dergleichen ersetzt wird. Die Fasern können vliesförmig vorgeformt oder lose eingestreut werden.Finally, one possibility for applying the connecting belt on the back of the sanding belt is that it is built up in layers on the sanding belt by at least partially pressing a random nonwoven into an initially applied plastic synthetic resin layer, after which the synthetic resin layer is allowed to harden. One or more additional layers can be applied. The synthetic resin can also be pressed in exclusively from the back of the nonwoven, the first synthetic resin layer then being omitted and possibly being replaced by an adhesion promoter or the like. The fibers can be preformed in a fleece shape or sprinkled loose.
Schematische Ausführungsbeispiele werden im folgenden anhand der Zeichnung erläutert. Darin zeigen:Schematic exemplary embodiments are explained below with reference to the drawing. In it show:
Fig. 1 eine perspektivische Ansicht eines endlosen Schleifbandes,1 is a perspective view of an endless grinding belt,
Fig. 2 und 3 zwei Draufsichten unterschiedlich ge¬ stalteter Verbindungsstellen,2 and 3 two plan views of differently designed connection points,
Fig. 4 einen Längsschnitt durch eineFig. 4 shows a longitudinal section through a
Verbindungsstelle,Liaison office,
Fig. 5 eine Draufsicht auf ein wirrfaserver¬ stärktes Verbindungsband,5 shows a plan view of a connecting tape reinforced with random fibers,
Fig. 6 einen Querschnitt durch ein Verbin¬ dungsband und Fig. 7 und 8 Längsschnitte durch unterschiedliche6 shows a cross section through a connecting band and 7 and 8 longitudinal sections through different
Ausführungsformen von Verbindungs¬ stellen.Embodiments of connection points.
Das Schleifband 1, das über ümlenkrollen 2 läuft, ist durch Verbindung seiner Enden im Bereich der Verbindungsstelle 3 endlos. Die Verbindungsstelle 3 verläuft schräg in einem Winkel 4 gegenüber der Schleifbandquerrichtung.The grinding belt 1, which runs over ummlenkrollen 2, is endless by connecting its ends in the area of the connection point 3. The connection point 3 runs obliquely at an angle 4 with respect to the transverse direction of the grinding belt.
Gemäß Fig. 2 bzw. 3 kann die Fuge 7 der Verbindungsstelle geradlinig oder nicht geradlinig verlaufen; gezeigt ist in Fig. 3 eine Wellenschnittverbindung.According to FIGS. 2 and 3, the joint 7 of the connection point can run in a straight line or not in a straight line; 3 shows a wave cut connection.
Gemäß Fig. 4 besteht das Schleifband aus der zugfesten, flexiblen Unterlage 5 und dem Schleifkornbelag 6. Bei 7 erkennt man die Fuge zwischen den zu verbindenden Bandenden. Die Verbindung wird vermittelt durch das Verbindungsband 8, das mit den benachbarten Rändern 9 der Schleifbandrückseite beispielsweise zur Klebung verbunden ist.4, the sanding belt consists of the tensile, flexible base 5 and the abrasive grain covering 6. At 7, the joint between the belt ends to be connected can be seen. The connection is mediated by the connecting band 8, which is connected to the adjacent edges 9 of the back of the grinding belt, for example for gluing.
Das Verbindungsband 8 enthält die Verstärkungsfasern 11 , gemäß der Draufsicht in Fig. 5 gleichmäßig verteilt, während sie im Querschnitt gemäß Fig. 6 in höherer Kon¬ zentration, insbesondere schichtförmig, in der Nähe der¬ jenigen Oberfläche 12 des Verbindungsbandes 8 enthalten sind, die zur Verklebung mit der Rückseite des Schleif- bandes 1 bestimmt ist. Ihre Länge liegt in der Größen¬ ordnung der Verbindungsbandbreite 10.The connecting band 8 contains the reinforcing fibers 11, according to the plan view in FIG. 5, evenly distributed, while in the cross section according to FIG. 6 they are contained in a higher concentration, in particular in layer form, in the vicinity of the surface 12 of the connecting band 8 which is intended for gluing to the back of the sanding belt 1. Their length is in the order of the connection bandwidth 10.
Vorzugsweise sind die Verstärkungsfasern 11 überwiegend parallel zur Ebene des Verbindungsbandes orientiert, was sich beispielsweise durch Dehnung des Bandes nach dem Gießen in Längs- und/oder Querrichtung oder durch Ein¬ bringung der Fasern als vorgebildetes Vlies bewerkstel¬ ligen läßt.The reinforcing fibers 11 are preferably oriented predominantly parallel to the plane of the connecting band, which can be produced, for example, by stretching the band after casting in the longitudinal and / or transverse direction or by introducing the fibers as a pre-formed nonwoven.
Wenn die Fasern 11 gemäß Fig. 7 über die Oberfläche 12 hinausstehen oder mindestens teilweise in dieser-frei liegen, können sie eine innige Verbindung mit der Bindemittelschicht 13 eingehen, die in dem dargestellten Beispiel zwischen der Rück¬ seite der Schleifbandunterlage 5 und dem Verbindungsband 8 vorgesehen ist.If the fibers 11 according to FIG. 7 protrude beyond the surface 12 or are at least partially free of it, they can form an intimate connection with the binder layer 13, which in the example shown is between the back of the sanding belt base 5 and the connecting belt 8 is provided.
In dem Beispiel gemäß Fig. 8 ist das Verbindungsband 14 in die Vertiefung eingeformt, die durch keilförmige Anschrägung der Ränder 15 der zu verbindenden Schleifbandenden geformt wurde. In the example according to FIG. 8, the connecting belt 14 is molded into the depression which was formed by wedge-shaped beveling of the edges 15 of the abrasive belt ends to be connected.

Claims

//Patentansprüche // claims
Schleifband mit einer von zwei Schleifbandenden gebil¬ deten Verbindungsstelle, die durch ein überlappend mit den Schleifbandenden verklebtes Verbindungsband (8) überbrückt ist, das in einer Kunstharzmatrix wirr orien¬ tierte Verstärkungsfasern (11) enthält, dadurch gekenn¬ zeichnet, daß die im wesentlichen ausschließlich wirr orientierten Fasern (11) eine mindeste mittlere Länge von der Größenordnung der Breite (10) des Verbindungs¬ bands (8) aufweisen und überwiegend auf dessen dem Schleifband (1) zugewendeten Querschnittsseite (12) an¬ geordnet sind. Sanding belt with a connection point formed by two sanding belt ends, which is bridged by a connecting belt (8) glued overlapping with the sanding belt ends and containing reinforcing fibers (11) which are tangled in a synthetic resin matrix, characterized in that they are essentially exclusively tangled fibers (11) have a minimum mean length of the order of the width (10) of the connecting belt (8) and are predominantly arranged on its cross-sectional side (12) facing the grinding belt (1).
2. Schleifband nach Anspruch 1 , dadurch gekennzeichne , daß die Fasern (11) schichtförmig mit einem im wesentlichen parallel zur Schleifbandebene liegenden Fase verlauf an¬ geordnet sind.2. Abrasive belt according to claim 1, characterized in that the fibers (11) are arranged in a layer shape with a chamfer lying essentially parallel to the abrasive belt plane.
3. Schleifband nach Anspruch 1 oder 2, dadurch gekennzeich¬ net, daß die Fasern (11) nur teilweise in dem Verbindungs¬ band (8) und zum anderen Teil in einer das Verbindungs¬ band (8) mit dem Schleifband (1).verbindenden Bindemittel¬ schicht (13) eingebettet sind.3. Abrasive belt according to claim 1 or 2, characterized gekennzeich¬ net that the fibers (11) only partially in the Verbindungs¬ band (8) and the other part in a Verbindungs¬ band (8) with the grinding belt (1). connecting binder layer (13) are embedded.
4. Schleifband nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Verbindungsfuge (7) wellenförmig, gezackt oder fingerförmig ineinandergreifend verläuft.4. Sanding belt according to one of claims 1 to 3, characterized in that the connecting joint (7) is wavy, serrated or finger-shaped interlocking.
5. Verbindungsband zum überlappenden Verbinden von zwei Schleifbandenden, das mit den Schleifbandenden zu ver¬ kleben ist und in einer Kunstharzmatrix wirr angeordnete Verstärkungsfasern (11) enthält, zur Herstellung eines Schleifbandes nach Anspruch 3, dadurch gekennzeichnet, daß die ausschließlich wirr orientierten Fasern (11) überwiegend an der mit dem Schleifband (1) zu verkleben¬ den Seite (12) des Bandes (8) angeordnet sind und dort teilweise freiliegen.5. connecting belt for overlapping connection of two ends of the sanding belt, which is to be glued to the ends of the sanding belt and contains reinforcing fibers (11) arranged tangled in a synthetic resin matrix, for the production of an sanding belt according to claim 3, characterized in that the exclusively tangled fibers (11 ) are arranged predominantly on the side (12) of the belt (8) to be glued to the grinding belt (1) and are partially exposed there.
6. Verfahren zum Herstellen eines Schleifbandes nach Anspruch 1 oder 2 mit einer von zwei Schleifbandenden gebildeten Verbindungsstelle, die durch ein überlappend mit den Schleifbandenden verklebtes Verbindungsband überbrückt ist, das in einer Kunstharzmatrix wirr orientierte Ver¬ stärkungsfasern enthält, wobei das Band durch Auftragen und Anpressen des im plastischen Zustand befindlichen Kunstharzes gebildet wird, dadurch gekennzeichnet, daß das Verbihdungsband auf dem Schleifband aufgebaut wird, indem ein Wirrvlies aufgelegt und anschließend eine zweite Kunstharzschicht aufgetragen und eingepreßt wird.6. A method for producing an abrasive belt according to claim 1 or 2 with a connection point formed by two ends of the abrasive belt, which is bridged by a bonded overlap with the ends of the abrasive belt, which contains confusion-oriented reinforcing fibers in a synthetic resin matrix, the band being applied and pressing the synthetic resin, which is in the plastic state, is formed, characterized in that the connecting band is built up on the grinding belt, by placing a tangled nonwoven and subsequently applying and pressing in a second synthetic resin layer.
7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß vor dem Auflegen des Wirrvlieses eine erste Kunstharz¬ schicht, ein Haftvermittler oder dergleichen aufgebracht wird. 7. The method according to claim 6, characterized in that a first layer of synthetic resin, an adhesion promoter or the like is applied before the tangled nonwoven is applied.
PCT/EP1985/000221 1983-11-09 1985-05-13 Abrasive belt with bonded splice WO1986006671A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP84113528A EP0142140A3 (en) 1983-11-09 1984-11-09 Abrasive belt with a junction reinforced with a synthetic resin strip
PCT/EP1985/000221 WO1986006671A1 (en) 1985-05-13 1985-05-13 Abrasive belt with bonded splice

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP1985/000221 WO1986006671A1 (en) 1985-05-13 1985-05-13 Abrasive belt with bonded splice

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Publication Number Publication Date
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1001200C2 (en) * 1995-09-15 1997-03-20 Aerpac Special Products B V Long windmill sail construction, useful e.g. for energy production
WO2000075530A1 (en) * 1999-06-09 2000-12-14 Habasit Nippon Co., Ltd. Structure and method for connecting flat belt
US7134953B2 (en) 2004-12-27 2006-11-14 3M Innovative Properties Company Endless abrasive belt and method of making the same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR928656A (en) * 1943-05-17 1947-12-04 Minnesota Mining & Mfg Improvements to abrasive products and method of manufacturing a sheet product coated with endless abrasive
US3154897A (en) * 1961-11-27 1964-11-03 Minnesota Mining & Mfg Spliced coated abrasive belt
FR2075760A5 (en) * 1970-01-20 1971-10-08 Fabriksaktiebolaget Eka

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR928656A (en) * 1943-05-17 1947-12-04 Minnesota Mining & Mfg Improvements to abrasive products and method of manufacturing a sheet product coated with endless abrasive
US3154897A (en) * 1961-11-27 1964-11-03 Minnesota Mining & Mfg Spliced coated abrasive belt
FR2075760A5 (en) * 1970-01-20 1971-10-08 Fabriksaktiebolaget Eka

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1001200C2 (en) * 1995-09-15 1997-03-20 Aerpac Special Products B V Long windmill sail construction, useful e.g. for energy production
WO2000075530A1 (en) * 1999-06-09 2000-12-14 Habasit Nippon Co., Ltd. Structure and method for connecting flat belt
US7134953B2 (en) 2004-12-27 2006-11-14 3M Innovative Properties Company Endless abrasive belt and method of making the same

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