SPIRAL FOR INTERCONNECTING ENDS OF ENDLESS BELT SEGMENTS

SPIRALE D'INTERCONNEXION D'EXTREMITES DE SEGMENTS DE COURROIE SANS FIN

English Abstract

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.

French Abstract

Une spirale d'interconnexion d'extrémités de segments de courroie sans fin utilisant un pivot. La spirale comprend un ensemble de boucles incluant des portions de boucle ayant la forme d'un U inversé qui s'étendent dans une direction transversale par rapport à la spirale. Les portions de boucle ont des pattes avant et arrière espacées les unes des autres pour le passage du pivot. Des portions de lien de boucle en U s'étendent diagonalement par rapport à l'axe longitudinal de la spirale, entre les extrémités inférieures des pattes avant et les extrémités inférieures des pattes arrière pour les portions de boucle suivantes, respectivement. Lesdites portions de boucle sont séparées les unes des autres d'une distance équivalant à la largeur des pattes des portions de boucle dans le sens longitudinal de la spirale, définissant ainsi des ouvertures aux fins d'engrènement avec une spirale similaire pour former un canal pour le pivot.

Claims

CLAIMS :
1. A spiral for interconnecting ends of endless belt segments with
terminal fabric loops using a pintle, comprising a series of loops each having
:
a preformed inverted U-shaped loop portion extending in a transverse
direction of the spiral, the loop portion having front and rear parallel legs
spaced
apart from each other for passage of the pintle therebetween, and an uppermost
head bending from and extending between the legs, the front and rear legs
having lower ends; and
a preformed U-shaped loop linking portion extending diagonally with
respect to a longitudinal direction of the spiral, between the lower end of
the front
leg of the loop portion and a lower end of a rear leg of a loop portion of a
next
one of the loops, the loop portions being parallel with and spaced from one
another by a definite pitch distance in the longitudinal direction of the
spiral
adapted to match with the fabric loops at the ends of the endless belt
segments
and to define openings for interdigitation with a like spiral to form a
channel for
the pintle without longitudinal deformation of the spirals during the
interdigitation,
at least the loop linking portion and the legs of the loop portion having a
uniform
cross-section, and the heads and the loop linking portions having
substantially
straight portions, so that the channel has a cross-section more rectangular
than
oblong.
2. The spiral according to claim 1, wherein the head of each loop portion
has projections made out of the spiral on opposite sides of the loop portion
in the
longitudinal direction of the spiral, for interlocking with like projections
on the like
spiral.
3. The spiral according to claim 2, wherein the series of loops are made
of a monofilament having a round cross-section.
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4. The spiral according to claim 3, wherein the projections of the heads
are made by flattening of the monofilament between the legs of each loop
portion.
5. The spiral according to claim 4, wherein the heads have an oval shape
when viewed from above.
6. The spiral according to claim 4, wherein the heads have a flared
profile with bent surfaces between the heads and the legs.
7. The spiral according to claim 1, wherein the series of loops are made
of a monofilament having a round cross-section.
8. The spiral according to claim 1, wherein the series of loops are made
of a monofilament of polyester, nylon, polyether ether ketone, or a
fluoropolymer.
9. The spiral according to claim 1, wherein the series of loops are made
of a monofilament of an atoxic polyester.
10. The spiral according to claim 1, wherein the series of loops are made
of a monofilament of hydrolysis-resistant polyester.
11. The spiral according to claim 1, wherein the pitch distance ranges from
one time to at least twice a diameter of a monofilament forming the spiral.
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Description

CA 02311845 2000-06-16
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
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CA 02311845 2000-06-16
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
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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 to 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
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CA 02311845 2000-06-16
longitudinai 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,
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.
10 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 6 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
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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.
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Representative Drawing