Leather perching machine

Abstract: An improved perching machine, in particular for softening and stretching industrial hides or the like, comprises at least one first section (5) and at least one second section (5') operationally coupled and located downstream of the first section; each section (5; 5') is formed by at least one pair of mutually facing conveyor belts (6, 7; 6', 7') for retaining and conveying the hides (P) and by at least one pair of plates (10, 12; 11, 13; 10', 12'; 11', 13') substantially parallel to the belts (6, 7; 6', 7') and acting on opposite sides thereof for softening and stretching the hides. The pair of conveyor belts (6', 7') of the downstream section has a feed speed (V') greater than that (V) of the pair of belts (6, 7) of the upstream section (5). Each section (5; 5') comprises independent motors (20, 20') operating a respective pair of conveyor belts (6, 7; 6', 7') so as to impart varied speeds (V', V) thereto. The ratio (V'/V) between the feed speed of the pair of belts of the downstream section and the speed of the pair of conveyor belts of the upstream section is between 1 and 4 and preferably equal to about 1.2. The advantage of exerting a greater stretching force on the hides in the longitudinal direction when passing from one section to the next one is obtained.

Description: The present invention relates to an improved perching machine, in particular for softening and stretching industrial hides or the like. It is known that the machines of the abovementioned type are used after the tanning and drying processes in order to restore the natural softness to hides and increase their extension or square footage. Such a machine is known from WO-A-97/17472, which represents the preamble of claim 1. These machines comprise one or more working heads each consisting of one or more pairs of substantially parallel plates which perform a periodic movement towards and away from each other in a direction substantially perpendicular to the plane in which they lie and between which the hides, retained by a pair of facing conveyor belts, are fed. The plates are normally provided with tools or projections able to co-operate during contact with projections or recesses with a matching shape on the opposite plate. Italian patent application No. VI99A000090 (cf WO-A- 00/68438) in the name of the same Applicants discloses a perching machine with several working heads comprising, among other things, two or more successive working sections each consisting of a series of contact plates or weights acting on opposite sides of a pair of mutually facing flexible conveyor belts which advance at a predetermined constant feed speed. The pairs of consecutive belts are operated by a single motor which causes feeding thereof at a uniform speed so as to move the hides continuously along the whole perching path. Motorised rollers are located in the space existing between the successive working sections, in the zone separating the pairs of facing belts, with the function of restoring the continuity between the adjacent conveyor belts and preventing the hides from falling. These rollers also rotate at a constant peripheral speed equal to the feed speed of the pairs of conveyor belts, so as to ensure the continuous feeding of the products being processed. Thus, each hide introduced into the machine, after passing through the first working section retained by the pair of facing belts, is conveyed by the intermediate rollers and introduced into the successive pair of belts which have the same peripheral speed so as to complete the perching action. Although this machine performs satisfactorily the functions for which it is designed, it may be subject to improvements, in particular in order to increase the degree of stretching of the hides in the longitudinal direction. The main object of the present invention is to devise an improved perching machine which allows a substantial increase in the degree of elongation of the hides in the longitudinal direction and therefore the overall square footage thereof. A particular object is to provide a perching machine which allows the hides to be stretched lengthwise during their feeding movement. A further object is to provide a perching machine which allows an adjustment in the degree of elongation in the longitudinal direction depending on the type of hides being processed. Last but not least, an object is to provide a perching machine with a hide feeding system which can be made using components readily available on the market so as to be advantageous from a purely economic point of view and easy to maintain. These objects, together with others which will emerge more clearly below, are obtained by means of an improved perching machine for softening and stretching industrial hides or the like, which, in accordance with Claim 1, comprises at least one first section and at least one second section operationally coupled and located downstream of the first section, each of said sections being formed by at least one pair of mutually facing conveyor belts for retaining and conveying the hides and by at least one pair of plates substantially parallel to said belts and acting on opposite sides thereof for softening and stretching the hides, characterized in that the pair of conveyor belts of the downstream section has a feed speed greater than the pair of belts of the upstream section. Owing to the greater feed speed of the conveyor belts of the downstream section, the hides are subject to a stretching action in the longitudinal direction when passing from the first section to the second section. The dependent claims describe detailed characteristic features of the machine according to the invention. Further characteristic features and advantages of the invention will emerge more clearly with reference to the description which follows of certain preferred, but not exclusive embodiments of an improved perching machine illustrated by way of a non-limiting example with the aid of the accompanying drawings, in which: Fig. 1 shows an overall side view of the hide perching machine according to the invention, partially sectioned along a longitudinal vertical plane; Fig. 2 shows an operating diagram of the machine according to Fig. 1. With reference to the figures mentioned, Figure 1 illustrates an embodiment of the perching machine according to the invention - denoted overall by the reference number 1 - which has an entry zone 3 and an exit zone 4 for the hides P to be processed which advance along a substantially horizontal plane W. The machine comprises a load-bearing bench or structure 2 which is formed by strong welded or bolted steel beams and on which a plurality of working sections or heads are mounted. In the embodiment shown in the Figures, the machine has two sections, i.e. a first section 5 and a second section 5', located in succession and operationally connected together. Obviously the working sections may also be greater than two in number, without thereby departing from the scope of the invention. The two sections 5, 5' are substantially similar to each other and have a certain number of parts necessary for feeding and processing of the hides P. In particular, the first section or upstream section 5 comprises means for feeding the hides P, consisting of a first pair of conveyor belts 6, 7 with respective portions 8, 9 which are substantially straight and horizontal and facing each other in order to retain the hides P inserted into the entry zone 3 of the machine. The section 5 also comprises one or more pairs of contact plates or weights - denoted respectively by 10, 11, 12, 13 - acting against the belts 6, 7 along their straight portions 8, 9 on opposite sides with respect to the feeding plane W of the hides P. In particular, the upper plates 10, 11 are fixed and secured stably to the bench 2, while the lower plates 12, 13 are movable and connected to the top end of connecting rods 14, 15 in turn moved by respective cams 16, 17 driven rotationally by motors 18, 19. In a manner known per se, the upper plates 10, 11 have suitable tools or projections able to co-operate with counter-tools or recesses of matching shape formed in the lower plates 12, 13. Alternatively, the position of the projections or recesses on the respective plates may be reversed or both the plates may be provided with projections which are suitably staggered so as to co-operate with each other and with the hides P. Similarly, the second section or downstream section 5' comprises a second pair of conveyor belts 6', 7' with respective portions 8', 9' which are substantially straight and horizontal and facing each other so as to retain the hides P located in between and to feed them towards the exit zone 4. The contact plate or weights, denoted respectively by 10', 11', 12', 13', act on the belts 6', 7' along their straight portions 8', 9', on opposite sides with respect to the feeding plane W of the hides P. According to the invention, the pair of conveyor belts of the downstream section has a feed speed V' greater than that of the pair of belts of the upstream section so as to exert on the hides a stretching force in the longitudinal direction when passing from one section to the next section. In a preferred embodiment, each section comprises an independent motor acting on a respective pair of conveyor belts so as to impart varied speeds thereto. In particular, a first electric motor 20 is coupled by means of a first drive belt 21 to the rollers 22, 23 which drive the first pair of conveyor belts 6, 7. Similarly, a second electric motor 20', independent of the motor 20, is coupled by means of a second drive belt 21' to the rollers 22', 23' which drive the second pair of conveyor belts 6', 7'. Means are provided for adjusting the speed of each individual motor 20, 20' so as to vary continuously the feed speed V, V' of each individual pair of conveyor belts 6, 7, 6', 7' or the feed speed ratio V/V' of the respective pair of conveyor belts. These adjusting means may consist of a microprocessor unit 24 connected to an interface 25 provided with a display 26 and keyboard 27 in order to allow an operator to program the variation in speed by means of the variation in the supply voltage of each individual motor 20, 20'. Advantageously, the ratio V'N between the feed speed V' of the pair of belts 6', 7' of the downstream section 5' and that V of the pair of conveyor belts 6, 7 of the upstream section 5 is between 1 and 4 and is preferably equal to about 1.2. Using a feed speed V, V' of between 2 m/s and 15 m/s and preferably between 3 m/s and 12 m/s excellent results are obtained. Advantageously, at least one motorised roller 28 is provided in the space located between the pairs of conveyor belts 6, 7, 6', 7' of the two sections, said roller optionally being driven by one of the conveyor belts 7' so that it has a tangential speed V" which is in between the speeds V, V' of the pairs of adjacent belts. Operationally speaking, after introducing a hide P into the entry zone 3, the said hide undergoes a stretching action which is more or less uniform in all directions while it is fed by the first pair of belts 6, 7 at a substantially constant speed V, after which it passes through the intermediate roller 28 to the second pair of conveyor belts 6', 7' at a substantially constant speed V'>V. In this way the hide undergoes a stretching action due to the differential speed Δ = V'-V and its incremental ratio Δ = V/N. For example, with V'=1.2 V a maximum percentage elongation of 20%, which is optimum for the perching treatment, is obtained. In an alternative embodiment, not shown in the drawings, the pairs of conveyor belts 6, 7 and 6', 7', respectively, of the two adjacent sections may be connected to a single motor by means of respective reducers having different transmission ratios so as to impart varied speeds to the pairs of belts. From that stated above, it can be understood that the perching machine according to the present invention achieves the predefined objects and in particular attention is drawn to its capacity to increase the stretching of the hides in the longitudinal direction of feeding thereof along the conveyor belts. Even though the claims which follow use reference numbers present in the description and the drawings, these numbers are purely indicative and do not limit in any way the scope of the invention.

Claims: Improved perching machine for softening and stretching industrial hides or the like, comprising at least one first section (5) and at least one second section (5') operationally coupled and located downstream of the first section, each of said sections (5; 5') being formed by at least one pair of mutually facing conveyor belts (6, 7; 6', 7') for retaining and conveying the hides (P) and by at least one pair of plates (10, 12; 11, 13; 10', 12'; 11', 13') substantially parallel to said belts (6, 7; 6', 7') and acting on opposite sides thereof for softening and stretching the hides, characterized in that the pair of conveyor belts (6', 7') of the downstream section has a feed speed (V') greater than that (V) of the pair of belts (6, 7) of the upstream section (5), so as to exert on the hides a stretching action in the longitudinal direction when passing from one section to the next section. Perching machine according to Claim 1, characterized in that it envisages that each section (5; 5') comprises independent motors (20, 20') operating a respective pair of conveyor belts (6, 7; 6', 7') so as to impart varied speeds (V', V) thereto. Perching machine according to Claim 1, characterized in that the pairs of conveyor belts (6, 7; 6', 7') of said sections (5; 5') are connected to a single motor by means of respective reducers having different transmission ratios so as to impart varied speeds to said pairs of belts. Perching machine according to Claim 2, characterized in that it envisages means (24, 25, 26, 27) for adjusting the speed of each individual motor so as to vary continuously the feed speed of each individual pair of conveyor belts or the ratio of the feed speeds of the respective pairs of conveyor belts. Perching machine according to Claim 4, characterized in that said adjusting means comprise a microprocessor unit (24) for varying the supply voltage of each individual motor. Perching machine according to Claim 1, characterized in that at least one motorised roller (28) with a tangential speed (V") in between the speeds (V,V') of the pair of belts (6, 7; 6', 7') of the adjacent sections (5; 5') is provided in the space between the conveyor belts (6, 7; 6', 7') of said sections (5, 5'). Perching machine according to Claim 1, characterized in that the ratio (V'N) between the feed speed of the pair of belts of the downstream section and the speed of the pair of conveyor belts of the upstream section is between 1 and 4. Perching machine according to Claim 1, characterized in that the ratio (V'V) between the feed speed of the pair of belts of the downstream section and the speed of the pair of conveyor belts of the upstream section is equal to about 1.2. Perching machine according to Claim 1, characterized in that the feed speed (V; V') of each pair of belts is between 2 m/s and 15 m/s. Perching machine according to Claim 1, characterized in that the feed speed (V, V') of each pair of belts (6, 7; 6', 7') is between 3 m/s and 12 m/s.

Inventors: POLATO ANTONIO, POLATO, ANTONIO
Applicants: CARTIGLIANO OFF SPA, OFFICINE DI CARTIGLIANO S.P.A.
Application year: 2001
Main classification: C14B1
IPC codes: C14B1