|1.||A device for joining the opposite ends of a belt (1) so as to form an endless belt, particularly in the form of a wire or felt for papermaking machines, the ends (1', 1") of the belt having first means (21, 2") for per¬ manently joining the belt ends, and removable second means (6, 6') for temporarily joining the belt ends during mounting of the belt, viz. in the form of plate members (6, 61) having gripping clamps or lugs (7) and attached to one side of the belt, said clamps being engageable with each other while effecting the temporary joining of the belt ends, c h a r a c t e r i s e d in that on the belt side opposing a clamping plate member (6, 6') there is arranged a second plate member (8, 8*) comprising a down¬ wardly or outwardly extending holdingdown element (9, 9*) serving to press the outermost end portion of said belt and, thus, said permanent connecting means (2', 2") against the associated clamping plate member (6).|
|2.||The device as claimed in claim 1, c h a r a c ¬ t e r i s e d in that said second plate member (8, 8' ) as well as said clamping plate member (6, 6') extend over the entire width of said belt (1).|
|3.||The device as claimed in claim 1 or 2, c h a ¬ r a c t e r i s e d in that said holdingdown element consists of a rib (9, 9') which preferably is integrally formed with the associated plate member (8, 8') and ex¬ tends over the entire length of said plate member.|
|4.||The device as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the side of said second plate member opposing the holdingdown element (9, 9') comprises at least one projection (10, 10') which preferably is ribshaped and manually grippable so as to facilitate the moving together of said belt ends.|
|5.||The device as claimed in any one of the precedin claims, c h a r a c t e r i s e d in that at least one clamping plate member (6' ) has a plurality of spacedapa slits (11) extending inwardly a distance away from the clamping edge (7) of the plate member, for example up to half the width of the plate member.|
|6.||The device as claimed in any one of the precedin claims, c h a r a c t e r i s e d in that the two plat members (6, 8; 6*, 8*) arranged on the opposite sides of belt end (1', 1") are interconnected and connected with said belt by a seam of thread (5) which, when destructed, allows simultaneous removal of said plate members from t belt.|
Technical field of the invention
The invention relates to a device for joining the op- posite ends of a belt so as to form an endless belt, par¬ ticularly in the form of a wire or felt for papermaking machines, the ends of the belt comprising first means for permanently joining the belt ends, and removable second means for temporarily joining the belt ends during mount- ing of the belt, viz. in the form of plate members having gripping clamps or lugs and attached to one side of the belt, said clamps being engageable with each other while effecting the temporary joining of the belt ends. Background of the invention Papermaking machines may have different types of endless belts in the form of wires or felts for carrying the paper web formed in the forming section of the machine through subsequent dewatering and final drying sections. After being used for a certain period of time, these wires or felts must be discarded and replaced by new ones, which is an arduous and difficult operation, not only because the wires are heavy and unwieldly (they may have a length of 80-120 m and a width of 7-12 m), but also because the operation must be carried out in hot and damp surroundings and in a short time. The connecting means which serve to permanently join the ends of a new wire, are in practice a great number of loops, clips or the like which are fitted alternately between each other, while forming a common channel through which a strong locking wire is passed so as to join the loops and, thus, the belt ends. These loops which can be pulled-out portions of the warps of the wire or felt or be formed on special edgings which are sewn on to the wire, are, for natural reasons, not allowed to have a diameter which evidently exceeds the thickness of the wire, since they would otherwise cause irregularities in the wire web. In actual practice, the diameter of the loops therefore is not larger than about 1-2 mm. Moving,
in the tough surroundings of a papermaking machine which has just been put temporarily out of operation, the two opposite ends of the heavy and unwieldly wire together exactly so that the loops of but a millimetre are exactly in alignment, is a most difficult operation.
To facilitate the above-mentioned mounting operation, SE Patent Specification 8301118-9 suggests that plate mem¬ bers or strips be mounted on the lower side of the two belt ends. The plate members are formed with clamps which can be caused to engage with each other while forming a temporary connection which holds the belt ends together as the permanent locking wire is passed through said loops. These two clamping plate members are sewn on to the end portions of the wire in predetermined, exact positions for the purpose of automatically aligning the loops, as soon as the clamps of the plate members engage each other. More precisely, the clamping plate members are offset re¬ lative to the belt ends in such manner that one plate mem¬ ber projects a distance beyond the associated end of the wire, while the other plate member is, with its clamping edge, retracted a corresponding distance from the asso¬ ciated end of the wire. As a result, the loops to be joined will be located on the last-mentioned plate member and a distance away from the clamps proper. However, in practice, this results in a problem which is difficult to master since the two plate members can rarely or never be kept in alignment in such manner that the two end portions of the wire are located in an absolutely planar state in the line of each other. Thus, the fitters are in most cases forced to put the wire ends on a drying cylinder or hold them in a self-supporting state between two cylin¬ ders. In both cases, the wire is more or less arcuate in the area of the belt ends, and because the wire has always a certain inherent rigidity, the loops of at least the wire end which projects a distance beyond the associated plate member will be located on a certain level above the underlying second plate member. In other words, the loops
of the two wire ends will be positioned on different levels relative to the underlying plate member, and to move them together correctly while forming a common rec¬ tilinear channel for the locking wire, they must be pressed down manually against the plate member, which in practice requires several fitters. Brief description of the inventive idea
The present invention aims at eliminating the above- mentioned drawback of the previously known device and at providing a joining device which automatically and com¬ pletely without any manual assistance ensures exact posi¬ tioning of the loops in alignment, as soon as the clamping plate members are caused to engage one another. According to the present invention, this is achieved primarily in that on the side of the belt opposing a clamping plate member, there is arranged a second plate member which comprises a downwardly or outwardly extending holding-down element serving to press the outermost end portion of the belt and, thus, said loops or permanent connecting means against the associated clamping plate member. Brief description of the accompanying drawings
In the drawings: Fig. 1 is a perspective view from below of a portion of a wire, while joining the opposite ends thereof, Fig. 2 is a schematic cross-sectional view of the two opposite ends of the wire in their spaced-apart state, and Fig. 3 is a similar cross-sectional view of the joined wire ends when joined. Detailed description of a preferred embodiment of the in¬ vention
The drawing shows a belt generally designated 1, in the form of a wire or felt whose two opposite ends which are initially spaced apart, are designated 1', 1". The wire end 1' (see Fig. 2 ) is provided with loops 2 1 which together with analogous loops 2" arranged on the other wire end 1" can join the two end portions, while forming
an endless wire web. More precisely, this is effected by means of a locking wire 3 with which a needle 4 can be thread and which can be passed through the loops 2* , 2" when these are moved together and f tted alternately be- tween each other while forming a rectilinear, common chan¬ nel. On one side, in this case the lower side of the end portions 1', 1" of the wire, two plate members 6, 6' are, in per se known manner, attached by seams 5, the free edge portions of the plate members facing away from the seams 5 comprising clamps 7 which can engage each other and form a temporary connection between the wire ends during mounting and permanent joining thereof. In the manner described in SE 8301118-9, the plate members 6, 6' can preferably be made of plastic and have the shape of elongate strips of uniform width which extend over the entire width of the wire 1. In practice, the plate members can be fairly thin (1-2 mm) and, consequently, elastically yieldable. The width can be 100-200 mm.
According to the principle of the invention, there is arranged on the side of the wire opposing the respective clamping plate member 6, 6* , i.e. in this case the upper side, a second plate member 8, 8' comprising a downwardly extending holding-down element 9, 9* serving to press the outermost end portion of the belt and, thus, the loops 2, 2' against the underlying plate member 6. In the shown, preferrred embodiment, also the plate members 8, 8 1 have the shape of elongate plastic strips of uniform width which extend over the entire width of the wire and the edges of which facing one another are formed with rib- shaped portions extending downward a distance from the strips as such and form said holding down elements 9, 9' . The strips 8, 8' can preferably have about the same width as the strips 6, 6' and be of the same thickness, the por¬ tions 9, 9' extending 5-10 mm beyond the lower side of the strips. Projections 10, 10' which are also rib-shaped extend upwardly from the upper side of the strips or plate members 8, 8 1 and constitute gripping means which can be
gripped manually so as to facilitate the moving together of the wire ends.
According to a special characteristic feature of the invention, the seam 5 is common to the two plate members arranged on the opposite sides of the wire end, e.g. the plate members 6 and 8, such that these two plate members are interconnected and also connected with the associated wire end. The thread of the seam 5 suitably is easily de¬ structible, such that the two plate members 6, 8 can be readily and quickly removed from the wire after mounting of the locking wire 3 simply by cutting off the thread. To this end, the thread is arranged in a zigzag pattern and extends through preformed holes in the respective plate member. According to a further characteristic feature of the invention, at least one clamping plate member, in this case the plate member 6' , has a plurality of spaced-apart slits 11 (of which only one is shown in Fig. 1) which ex¬ tend inwardly a distance away from the clamping edge 7 of the plate member, for example up to half the width of the plate member. The presence of the slits 11 facilitates the moving together of the wire ends, in that the plate mem¬ bers 6' and 6 can be moved together, piece by piece. As a result, the two clamping plate members 6, 6' need not be kept absolutely in parallel, as they are caused to engage each other.
As is best shown in Figs. 2 and 3, both the clamping plate members 6, 6' and the holding-down plate members 8, 8' are laterally offset relative to the loops 2', 2", more precisely in such manner that the clamping plate member 6 projects a distance beyond the associated loops 2", while the clamping plate member 6' is retracted a "Corresponding distance relative to the associated loops 2". The holding- down plate members 8, 8' are, however, both retracted a short distance relative to the loops 2', 2". Therefore, when the clamps 7, after the wire ends have been moved to¬ gether, engage each other, as shown in Fig. 3, while form-
ing a temporary connection of the wire ends, the loops 2 1 , 2" will be located on the upper side of the clamping plat member 6, the holding-down elements 9, 9' of the two plat members 8, 8' being located on each side of the loops which have been moved together. Since the plate members 8,8' are resilient or elastic, the holding-down elements 9, 9' will automatically press down the outermost end portions of the wire in the immediate vicinity of the loops and thus hold the two types of loops 2', 2" dis- tinctly pressed against the upper side of the clamping plate member 6, such that these together define an abso¬ lutely rectilinear channel into which the locking wire 3 can readily be inserted and passed through, while perma¬ nently interlocking the wire ends. Possible modifications of the invention
The invention is, of course, not restricted to the embodiment described above and shown in the drawings. Thus, for the permanent joining of the wire ends, use can be made of other means than precisely loops, e.g. clips, spirals or the like. It is further conceivable to form th holding-down elements 9 in some other manner than as rib- shaped one-piece portions integrally formed with the plat members 8, 8'. Thus, said rib portions can be replaced by a great number of spaced-apart lugs. Instead of a single one-piece plate member or strip 8 at each end of the wire use can analogously be made of a great number of separate plate members of limited length which are preferably ar¬ ranged closely together. Although the present invention has been described above in connection with precisely a wire or felt, it is of course also possible to apply the inventive idea to other belts of any type whose opposite ends are to be joined so as to form an endless belt.