ROLLER GLUEING MACHINE FOR PROCESSING LEATHER GOODS

Abstract: A roller glueing machine (10) for processing leather goods is described, comprising at least one nip roller (12) supported on a shaft (16), a coating counter-roller (14) for adhesive and means for actuating said shaft (16) for pressing said at least one nip roller (12) towards said coating counter-roller (14), wherein said shaft (16) is cantilevered at a first end (18), characterised by means for compensating the horizontality of said shaft (16), said compensation means exerting a force at the free end (26) of said shaft (16) towards said coating counter-roller (14). An even coating of adhesive along the entire gap with the counter-roller is thus provided.

Description: "Roller glueing machine for processing leather goods" ** ** ** ** DESCRIPTION The present invention relates to a roller glueing machine for processing leather goods. Although in recent years the field of leather goods has mainly tended towards the use of spray adhesives, the roller coating of adhesives such as latex, water-based neoprene or other water-based adhesives provides significant advantages, among which are a better grip, lower toxicity, a cost saving up to 30 - 40%, and a greater cleanness, both because the roller coating prevents dispersion beyond the item, and also because, in the case of latex, the machine may be cleaned by simply removing dried latex from the rollers. A roller glueing machine essentially comprises an upper nip roller and a coating counter-roller for the adhesive, which draws from a container in which it is partly immersed. Although in the present description a nip roller will be referred to for shortness, it must be understood that, for example, for processing stripe-shaped items such as belts, stripes, shoulder straps and the like, the nip roller can be replaced by two or more contiguous rollers assembled on the same shaft, if necessary shaped so as to be complementary to the fleshed portion of the item being processed. When a leather item passes through the gap between the rollers, the nip roller is lowered toward the counter- roller; the item is thus coated with adhesive onto its lower side. In a first type of roller glueing machine, the shaft of the nip roller is supported at both ends within two parallel uprights; however, this type of arrangement has two intrinsic disadvantages. In fact, the dimension of the glueing span is fixed; thus, this type of glueing machine cannot be used, in particular, for glueing end portions of bulky objects, such as handbag hems and the like. In addition, the disassembly of the nip roller, for example for cleaning or replacing, is cumbersome. To obviate said problems, a second type of roller glueing machine is known, wherein the nip roller is cantilevered, that is to say, it is supported only at one end. With this arrangement, however, there is the problem that the pressure exerted along the gap with the coating counter- roller is not sufficiently even, since the shaft loses parallelism during the pressure step. In particular, this means that the glueing along the width of the item being processed is not even, and it could even be missing at the side corresponding to the free end of the shaft of the nip roller . Object of the present invention is to provide a roller glueing machine that obviates the above disadvantages of both types of known roller glueing machines, that is to say, a type of roller glueing machine wherein the nip roller is cantilevered, but still keeps the parallelism in the pressure step so as to produce an even coating of adhesive along the entire gap with the counter-roller. This problem is solved by a roller glueing machine for processing leather goods according to claim 1. Further advantageous features of said glueing machine are recited in the dependent claims . Features, purposes and advantages of the present invention will appear more clearly from the following description and the attached drawings, relating to not limitative exemplary embodiments . The various Figures, in which like or similar reference numbers refer to equal or equivalent parts, show: - Figure 1: a roller glueing machine according to a first embodiment of the present invention; - Figure 2 : a roller glueing machine according to a second embodiment of the present invention; - Figure 3 : a roller glueing machine according to a third embodiment of the present invention; and - Figure 4: a roller glueing machine according to a fourth embodiment of the present invention. With reference to Figure 1, a roller glueing machine 10 according to a first embodiment of the present invention comprises an upper nip roller 12 and a coating counter- roller 14 for the adhesive, which draws from a container (not shown) in which it is partly immersed. The nip roller 12 is assembled on a shaft 16 supported at a first end 18 to the glueing machine, and provided with actuating means for lowering it towards the coating counter-roller 14, for example in the shape of a lever 20 operated by a pedal 22 through a traction cable 24, schematically illustrated by a dashed line, and provided with a return spring (not shown) . At the free end 26 of shaft 16, a compensation system is provided for maintaining the shaft horizontal, in the shape of a lever 28 one free end 30 of which, in the lowered position of lever 28, engages the end 26 of shaft 16 pushing it towards the coating counter-roller 14. Bearing means, for example in the shape of a wheel 32 at the free end 30 of lever 28, are provided for the purpose of favouring the rolling of shaft 26. In the embodiment of Figure 1, lever 28 is operated by a traction cable 34 controlled by the same pedal 22 which operates the lever 20 for actuating the nip roller 12; thus, the two levers 20, 28 are operated simultaneously. Finally, there are shown a return spring 36 and a dowel 38 to adjust the position of the lever according, for example, to the thickness of the material being processed. It must be noted that, with the particular double-angle configuration of the lever shown, the gap between the two rollers 12, 14 is freely accessible from the side corresponding to the free end 26 of shaft 16, thus allowing processing end portions of bulky items. The embodiment shown in Figure 2 differs from the above one in that levers 20, 28 are actuated through a respective piston and cylinder device, 40, 42 respectively, for example of the pneumatic type. Advantageously, the operation is controlled by a sensor, for example an optical reader 44, which detects the presence of an item in the gap between the nip roller 12 and the coating counter-roller 14. Figure 3 shows a simplified compensation system wherein a piston and cylinder device 46 directly operates with the free end of its piston rod 48 against the free end 26 of shaft 16, preferably provided with the bearing wheel 32. Also in this case, sensor 44 advantageously controls the operation. Finally, Figure 4 shows another compensation system wherein the piston rod 52 of a piston and cylinder device 50 is provided with a joint 54 with bearings so as to exert a pull action on the free end 26 of shaft 16, preferably in response to the detection of an item by sensor 44. However, this type of embodiment is not suitable for bulky items since it takes up the insertion side of the gap between the rollers 12, 14, and requires the removal of joint 54 for maintenance, cleaning and replacing of roller 18. For sake of simplicity, Figures 3 and 4 do not show the actuating means at the supported end 18 of shaft 16, which can be of any traditionally used type, preferably as shown in the embodiment of Figure 2.

Claims: CLAIMS 1. Roller glueing machine (10) for processing leather goods, comprising at least one nip roller (12) supported on a shaft (16) , a coating counter-roller (14) for adhesive, and means for actuating said shaft (16) for pressing said at least one nip roller (12) towards said coating counter- roller (14) , wherein said shaft (16) is cantilevered at a first end (18) , characterised by means for compensating the horizontality of said shaft (16) , said compensation means exerting a force at the free end (26) of said shaft (16) towards said coating counter-roller (14) . 2. Roller glueing machine (10) according to claim 1, characterised m that said compensation means comprise a lever (28) m a lowered position of which, one free end (30) thereof engages said free end (26) of said shaft (16) thus forcing it towards said coating counter-roller (14) . 3. Roller glueing machine (10) according to claim 2, characterised in that said free end (30) of said lever (28) is provided with bearing means (32) for the rolling of said shaft (16) . 4. Roller glueing machine (10) according to claim 2 or 3 , characterised m that said lever (28) has a double-angle configuration so as to be pivoted from the side of said first supported end (18) of said shaft (16) . 5. Roller glueing machine (10) according to claim 1, characterised m that said compensation means comprises a piston and cylinder device (46, 50), m an end-of-stroke position thereof the end of its piston rod (48, 52) engaging said free end (26) of said shaft (16) thus forcing it towards said coating counter-roller (14) . 6. Roller glueing machine (10) according to claim 5, characterised m that the end of said piston rod (48, 52) is provided with bearing means (32, 54) for the rolling of said shaft (16) . 7. Roller glueing machine (10) according to any of the previous claims, characterised by synchronisation means (22, 44) for actuating said compensation means simultaneously with the actuation of said at least one nip roller (12) by said means for actuating said shaft (16) . 8. Roller glueing machine (10) according to any of the previous claims, characterised by sensor means (44) for detecting the presence of an item inside the gap between said at least one nip roller (12) and said coating counter- roller (14) and for operating, in response to this, said compensation means and said means for actuating said shaft

Inventors: ZANETTI PIERO, ZANETTI, PIERO
Applicants: ZANELLATI E ZANETTI S N C, ZANETTI PIERO, ZANELLATI E ZANETTI, S.N.C., ZANETTI, PIERO
Application year: 2000
Main classification: B05C1
IPC codes: B05C1