Note: Descriptions are shown in the official language in which they were submitted.
' CA 02229371 1998-02-13
Express Mail Label No.: EM394698272
FA~RIC MADE FROM ~l~ED, CUT TO SIZE HOLLOW TUBES
BACRGROUND OF THE lNv~NLlON
Field of t.he Invention
The present invention concerns a link belt, especially for
paper machines, with hinge wires extending in the cross machine
direction and link elements extending in the machine direction.
Each link encloses at least two adjacent hinge wires.
Description of the Prior Art
A pa?ermaker's link belt fabric has been disclosed in U.S.
Patent No. 4,469,221. It has a number of circular hinge wires
running in the cross machine direction bound together via link
elements. A number of differently shaped link elements are shown.
Each link element has passage openings at its ends for accepting
neighborillg hinge wires. The passage openings are slit to permit
them to be expanded and snapped around the hinge wires.
In such a link belt, there is a possibility of expansion of
the slit passage openings and, also, only a limited stability in
lhe direction of tensioning. Additionally, the link elements are
prone to breaking at the expandable sections bordering the passage
openings. Another disadvantage of such a link belt is that air
permeability can not be adjusted significantly. Since link belts
are generally used in the dryer section of a paper machine, air
permeability is an important property and therefore is preferably
adjustable.
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So-called wire link belts are described in U.S. Patent Nos.
4,395,308 and 5,364,692. Such wire link belts also have a number
of hinge wires extending in the cross direction. The hinge wires
may be circular, flat, oval, or rectangular in cross section or a
variation thereof. In wire link belts, the hinge wires join
together wire spirals, each of which surrounds two neighboring
hinge wires. Generally, each wire spiral intermeshes with its
neighboring wire spirals.
In some applications, filler elements may be incorporated
between each pair of hinge wires in the area surrounded by the wire
spirals to reduce the air permeability as disclosed in U.S. Patent
No. 5,364,692. Permeability may also be reduced by providing
spirals having upper or lower surfaces which are wider than the
ends thereof, as disclosed in U.S. Patent No. 4,528,236, which is
1'; incorporated herein by reference.
However, the manufacture of wire link belts is not simple.
(,enerally, the wire spirals are produced via plastic deformation
under the influence of heat. This is an expensive, tedious and
time consuming process. In addition, left- and right-spiraled wire
2() spirals have to be kept on hand to be joined and intermeshed with
each other in a proper sequence. A further disadvantage is that
damage to a single wire spiral can result in a break of the entire
wire link belt.
Therefore, there exists a need for a link belt that it is
resistant to tension, can be adjusted for air permeability, and can
be easily produced.
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SUMMARY OF THE INVENTION
The present invention generally provides a paper machine belt
comprising hinge wires extending in the cross machine direction and
a plurality of ring link elements extending in the machine
direction. Each ring link element opens in the cross machine
direction and encloses at least two of the hinge wires.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an isometric view of a link belt made in
accordance with the present invention.
Figure 2 is a side elevation of the link belt of Figure 1.
Figure 3 is a top plan view of the link belt of Figure 1.
Figure 4 is a top plan view of an alternate embodiment of the
link belt.
Figure 5 is a side elevation of the link belt of Figure 4.
FiguIe 6 is a top plan view of a second alternate embodiment
of the link belt.
Figure 7 is a side elevation of the link belt of Figure 6.
Figure 8 is a top plan view of a third alternate embodiment of
the link belt.
Figu:re 9 is an isometric view of a preferred tube and ring
elements :Eormed therefrom.
Figu:re 10 is an isometric view of an alternate embodiment of
a ring link element.
Figure 11 is a side elevation of the ring link element of
Figure 10.
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Figure 12 is a partial isometric view of a link belt forming
apparatus.
Figures 13a-19a are side elevation views of the forming
apparatus of Figure 12 during formation of a link belt. -
Figure~ 13b-19b are front elevation views of the forming
apparatus of Figure 12 during forming of a link belt.
Figure~ 13c-19c are top views of the forming apparatus of
Figure 12 during formation of a link belt.
Figures 20-27 are top views of an alternate forming apparatus
during forming of a link belt.
DETAILED DESCRIPTION OF THE INVENTION
The I?referred embodiments will be described with reference to
drawing figures where the numerals represent like elements
throughout.
As shown in FigureR 1-8, the link belt 1 has a number of hinge
wires 2 extending in the cross machine direction. The hinge wires
2 can have various cross sections, such as the hinge wires
presently used in spiral link belts. They are preferably equally
spaced with respect to each other.
Each pair of neighboring hinge wires 2 is jointly surrounded
by a ring element 3 having a single opening 4. Preferably, the
ring elements 3 are adapted to the shape of the hinge wires 2 in
that the ring openings 4 correspond to the geometry of the hinge
wires 2. It i8 preferable that the hinge wires 2 and ring openings
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4 be roundid along their lateral edges regardless of their cross
section as part of the hinging function.
In the preferred embodiment, the ring elements 3 have a
substantially quadratic cross section and run straight on the top
and bottom side. In this way, flat surfaces are formed. It is
also possible to provide convex or concave surfaces in order to
attain bett:er adaptation to specific conditions. The ring elements
3 may have a variety of configurations, such as those currently
utilized in spiral link belts. The configuration shown in Figure
8 is similar to that disclosed in U.S. Patent No. 4,528,236. In
this configuration, the top and bottom surfaces of each ring 3 are
wider than the ends thereof.
Referring to Figure 1, two neighboring ring elements 3 are
arranged around hinge wire 2 and offset with respect to each other
in the machine direction. For example, ring element 3b encloses
two specific hinge wires 2b and 2c. Neighboring ring element 3a
surrounds only one of the two above-mentioned hinge wires 2b as
well as the next hinge wire 2a in the machine direction. Ring
element 3c encloses the other of the two above-mentioned hinge
wires 2c as well as the hinge wire 2d neighboring on the other
side. This pattern is continuous so that two neighboring hinge
wires 2 are jointly surrounded by only every other ring element 3
~iewed in the cross direction of the link belt 1. It is also
possible for the ring elements 3 to enclose three or more
successiv,- hinge wires 2, the spacing of the hinge wires 2 being
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held constant in such an embodiment through appropriate staggering
of the ring elements 3. This is shown in Figures 6 and 7.
When the belt 1 is assembled, channel 6 extends in the cross
direction between neighboring hinge wires 2 over the entire width
of the linl~ belt 1. Filler elements, such as are found in U.S.
Patent No. 5,364,692, can be placed in these channels 6. In this
way, the air permeability of the link belt 1 can be adjusted to a
desired value. If desired, a woven or non-woven batt layer can be
affixed to one or both sides of the belt in a known manner, such as
is disclosed in U.S. 4,528,236.
The ring elements 3 and the hinges 2 can be formed from any
number of materials, including but not limited to plastics, metals,
or any cornbination thereof. The materials may be treated or
reinforced by additives such as fiberglass. As shown in Figure 9,
the ring elements 3 are preferably sections of a desired width,
that are formed from a continuous hollow tube 10 of the desired
cross sect:ion. In the preferred embodiment, tube 10 is an
extrusion and the ring elements 3 are formed in a cutting
apparatus. Alternatively, the ring elements 3 may be injection
molded.
An alternate ring element 103 is shown in Figures 10-11. In
this embocliment, the machine side of the ring element 103 has a
separation 105. The ring element 103 may be formed with this
configurat:ion or may be formed flat and then bent to the desired
configurat.ion. These ring elements 103 may be used to form an
entire bel.t, but are preferably used only as replacement elements
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for fabric elements which are broken or damaged since they will not
be required to provide as much MD stability in such an application.
A first method of manufacturing the belt 1 is shown in Figures
12-19. The forming apparatus 20 extends in the cross direction and
comprises a ring discharger 22, a forming platform 24 and an
advancing arm 26. The ring discharger 22 is supplied with ring
elements 3. Preferably, the number of stacks of ring elements 3 is
equal to half the number of ring elements 3 in the machine cross
direction of the desired belt. The stacks are spaced in the cross
machine direction by a distance equal to the width of a ring
element 3.
Assembly of the belt 1 is shown in Figures 13-19, wherein each
figure re~resents a progression in the formation process. As shown
in Figures 13a-13c, when the ring discharger 22 is in a first
1', alignment, the even row ring elements 28 drop to the forming
platform :'4. Next, as shown in Figures 14a-14c, advancing arm 26
preferably advances the even row ring elements 28 in the machine
direction by one half of a ring element. Simultaneously, the ring
discharger 22 moves in the cross machine direction by the width of
a ring element to its second alignment. When the advancing arm 26
is removed, as shown in Figures 15a and 15c, the odd row ring
elements 27 fall to the forming platform 24, as shown in Figure
15a. A forming wire 2 is placed through the channel by the aligned
positions of ring elements 27 and 28, as shown in Figures 16a and
16c. The advancing arm 26 advances the belt 1 in the machine
direction while the ring discharger 22 simultaneously moves back to
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its first alignment, as shown in Figure 17. When the advancing arm
26 is withdrawn as shown in Figures 18a and 18c, the next group of
even row ring elements 28 falls to the forming platform. A pintle
wire 2 is inserted through the channel formed by the advanced ring
elements 27 and the newly positioned ring elements 28, às shown in
Figures l9a and l9c. This process is repeated to form a belt 1 of
a desired length.
An a:lternate method of forming the link belt 1 is shown in
Figures 20-27. The forming apparatus 40 extends in the cross
machine direction and comprises a forming jig 42 and advancing pins
44. As shown in Figure 20, hollow tubes 10 are inserted into the
jig 42. Individual ring elements 3 are formed across the desired
width of the forming apparatus 40. Odd rows of the ring elements
27 are then advanced in the machine direction by the advancing pins
1', 44, as shown in Figure 22. Hinge wires 2 are inserted in the
channels :Eormed between the advanced odd row ring elements 27 and
the non-advanced even row ring elements 28, as can be seen in
Figure 23.. The assembled portion of the belt 1 is advanced beyond
the jig 42 and hollow tubes 10 are again inserted into the cutting
jig 42, as shown in Figure 24. The advancing pins 44 advance the
even row ring elements 28 in the machine direction to align with
the last of the previously advanced odd row ring elements 27, as
can be seen in Figure 2 5. Hinge wires 2 are then inserted into the
newly formed channels. As can be seen in Figure 27, a hinge wire
2 5 2 j oins the advanced portion of the belt 1 with the newly advanced
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ring elements 28. The assembled belt is advanced as the process
continues to form a belt 1 of a desired length.
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