SPIRAL FOR INTERCONNECTING ENDS OF ENDLESS BELT SEGMENTS

Abstract: A spiral for interconnecting ends of endless belt segments using a pintle. The spiral comprises a series of loops (2) including inverted U-shaped loop portions (4) extending in a transverse direction (6) of the spiral. The loop portions (4) have front and rear legs (8, 10) spaced apart from each other for passage of the pintle therebetween. U-shaped loop linking portions (12) extend diagonally with respect to a longitudinal direction (7) of the spiral, between lower ends of the front legs (8) and lower ends of the rear legs (10) of the next loop portions (4) respectively. The loop portions (4) are spaced from one another by a distance (14) corresponding to a width (16) of the legs (8, 10) of the loop portions (4) in the longitudinal direction (7) of the spiral, thereby defining openings (17) for interdigitation with a like spiral to form a channel (19) for the pintle.

Description: SPIRAL FOR INTERCONNECTING ENDS OF ENDLESS BELT SEGMENTS FIELD OF THE INVENTION The present invention relates to a spiral for interconnecting ends of endless belt segments. BACKGROUND Segments of an endless belt have ends provided with sets of loops interdigitatable with one another so that the segments can be connected together by insertion of a pintle into the channel formed by the interdigitated sets of loops of two adjacent belt segments. The sets of loops and the pintle are however subjected to high stresses and strains during operation of the endless belt, so their design and strength are of utmost importance as a loose segment or pintle may cause important damages to the machine or serious injuries to a passer-by. The sets of loops are frequently provided by spirals seamed at the ends of the belt segments. US patent no. 5,915,422 (Fagerholm) shows an example of such a spiral attached at the end of a woven (felt) belt. When viewed sideways, the spiral exhibits a series of V-shaped loops spaced from one another by straight sections especially intended to receive flat filament yarns for attachment of the spiral to the end of the belt section. The interdigitation of two such spirals at the ends of adjacent belt sections is however uneven and unsteady due to the mismatching of the loops between the two interdigitated sets and the large spaces left between the loops for the yarns. Furthermore, the interdigitation is frequently incomplete or partial as a result of the non-complementary shapes of the spirals, so the resulting channel has a reduced size compared to the size of the loops and thus only a small size pintle can disadvantageously be used instead of a larger size one. SUMMARY An object of the invention is to provide a spiral for interconnecting ends of endless belt segments using a pintle, which better interdigitates with like spirals than the spirals of the prior art and which allows the use of larger size pintle for interlocking the spirals together. Another object of the invention is to provide such a spiral having loops that fully insert down to the bottom of a like spiral. Another object of the invention is to provide such a spiral which can be easily manufactured in a large range of sizes to fit multiple needs and applications. According to the present invention, there is provided a spiral for interconnecting ends of endless belt segments using a pintle. The spiral comprises a series of loops including inverted U-shaped loop portions extending in a transverse direction of the spiral. The loop portions have front and rear legs spaced apart from each other for passage of the pintle therebetween. U-shaped loop linking portions extend diagonally with respect to a longitudinal direction of the spiral, between lower ends of the front legs and lower ends of the rear legs of the next loop portions respectively. The loop portions are spaced from one another by a distance corresponding to a width of the legs of the loop portions in the longitudinal direction of the spiral, thereby defining openings for interdigitation with a like spiral to form a channel for the pintle. Each loop portion may have an uppermost head extending between the legs and projecting on opposite sides of the loop portion in the longitudinal direction of the spiral, for interlocking with like heads on the like spiral. The spiral according to the invention almost fully blends with a like spiral, which leaves more inner space for a larger pintle or for receiving a filling material. BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of preferred embodiments will be given herein below with reference to the following drawings, in which like numbers refer to like elements: Figure 1 is a side elevation view illustrating a spiral according to the invention; Figure 2 is a side elevation view illustrating a spiral with interlocking heads according t ' o the invention; Figure 3 is a perspective view illustrating a spiral according to the invention; and Figure 4 is a perspective view illustrating two spirals with interlocking heads during interdigitation in order to interconnect ends of endless belt segments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figures 1 and 3, there is shown a spiral according to the invention, for interconnecting ends of endless belt segments using a pintle (not shown in the Figures) . The spiral comprises a series of loops 2 each including an inverted U-shaped loop portion 4 extending in a transverse direction of the spiral, as depicted by arrow 6 in Figure 3. The loop portion 4 has front and rear legs 8, 10 spaced apart from each other for passage of the pintle therebetween, as best shown in Figure 3. Each loop 2 also includes a U-shaped loop linking portion 12 extending diagonally with respect to a longitudinal direction 7 of the spiral, between a lower end of the front leg 8 of the loop portion 4 and a lower end of a rear leg 10 of a loop portion 4 of a next one of the loops 2. The loop portions 4 are spaced from one another by a distance 14 substantially corresponding to a width 16 of the legs 8, 10 of the loop portions 4 in the longitudinal direction 7 of the spiral, thereby defining openings 17 for interdigitation with a like spiral to form a channel 19 for the pintle, as best shown in Figure 4. The series of loops 2 can be made of a single wire of polyester (trademark), nylon (trademark), PEEK (PolyEther Ether Ketone) , PVDS (Fluoropolymer) , Ryton (trademark) , or any other suitable material. For interconnection of belt segments in paper industries, a polyester that resists to hydrolysis should preferably used. For interconnection of belt segments in food industries, an atoxic material should be used. The wire may have a flat cross-section, providing more inner space for the channel 19. The spirals according to the invention can be seamed or otherwise attached to the ends of the belt segments to be interconnected with yarns woven in the belt segments and curling back around the linking portions 12. Referring to Figure 2, each loop portion 4 may be provided with an uppermost head 18 extending between the legs 8, 10 and projecting on opposite sides of the loop portion 4 in the longitudinal direction 7 of the spiral, for interlocking with like heads on the like spiral as exemplified in Figure 4. The heads 18 can be made by a flattening of the wire between the legs 8, 10 of each loop portion 4, provided that the wire has a cross-section suitable for the flattening operation, e.g. a round cross- section. Such a feature is particularly useful to hold back the spirals together the time to install the pintle inside the channel 19. However, a loss in the strength of the resulting interconnection is likely to happen due to the flattening of the wire to form the heads 18 when made in this way. Referring to Figure 3, the legs 8, 10 of each loop portion 4 may be longer than a width 20 of the loop portion 4 in the transverse direction 6 of the spiral, so that the channel 19 has an obround cross-section adapted to receive a flat pintle. Referring to Figure 4, typical sizes of spirals made according to the invention are 5.2 mm (height) x 2.6 mm (transverse width), 3.7 mm x 2.2 mm, and .38 mm x .63 mm. Larger or smaller sizes can also be used, provided that the loop per spiral rate is adjusted accordingly. The gauge of the wire used to make the spiral can be chosen according to the needs (desired strength, available space for the spiral, etc.). The design of the spirals according to the invention allows to two interdigitated spirals to reach the bottom of the other. With the larger channel obtained with the spirals according to the invention, a larger (stronger) pintle can be used, or a remaining gap in the channel after pintle insertion can be filled with a suitable material. While embodiments of this invention have been illustrated in the accompanying drawings and described above, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention. All such modifications or variations are believed to be within the scope of the invention as defined by the claims appended hereto.

Claims: CLAIMS : 1. A spiral for interconnecting ends of endless belt segments using a pintle, comprising a series of loops (2) including: an inverted U-shaped loop portion (4) extending in a transverse direction of the spiral, the loop portion (4) having front and rear legs (8, 10) spaced apart from each other for passage of the pintle therebetween, the front and rear legs (8, 10) having lower ends; and a U-shaped loop linking portion (12) extending diagonally with respect to a longitudinal direction (7) of the spiral, between the lower end of the front leg (8) of the loop portion (4) and a lower end of a rear leg (10) of a loop portion (4) of a next one of the loops (2), the loop portions (4) being spaced from one another by a distance (14) substantially corresponding to a width (16) of the legs (8, 10) of the loop portions (4) in the longitudinal direction (7) of the spiral, thereby defining openings (17) for interdigitation with a like spiral to form a channel (19) for the pintle. 2. The spiral according to claim 1, wherein each loop portion (4) has an uppermost head (18) extending between the legs (8, 10) and projecting on opposite sides of the loop portion (4) in the longitudinal direction (7) of the spiral, for interlocking with like heads on the like spiral. 3. The spiral according to claim 1, wherein the legs (8, 10) of each loop portion (4) are longer than a width (20) of the loop portion (4) in said transverse direction (6), so that the channel (19) has an obround cross-section. 4. The spiral according to claim 1, wherein the series of loops (2) are made of a single wire having a flat cross- section. 5. The spiral according to claim 2, wherein the series of loops (2) are made of a single wire having a round cross- section. 6. The spiral according to claim 5, wherein the heads (18) are made by flattening of the wire between the legs (8, 10) of each loop portion (4). 7. The spiral according to claim 1, wherein the series of loops (2) are made of a single wire of polyester, nylon, polyether ether ketone, or a fluoropolymer . 8. The spiral according to claim 1, wherein the series of loops (2) are made of a single wire of an atoxic polyester. 9. The spiral according to claim 1, wherein the series of loops (2) are made of a single wire of hydrolysis- resistant polyester.

Inventors: CORRIVEAU ANDRE, CRETE SYLVAIN, FRASER CAROLINE, PLANTE JEAN-SEBASTIEN, CORRIVEAU, ANDRE, CRETE, SYLVAIN, FRASER, CAROLINE, PLANTE, JEAN-SEBASTIEN
Applicants: LIPPERT PINTLEPIN MFG INC, LIPPERT PINTLEPIN MFG. INC.
Application year: 2001
Main classification: F16G3
IPC codes: D21F1, F16G3