WO2003023068A1

WO2003023068A1 - Control system for hide processing machines

Info

Publication number: WO2003023068A1
Application number: PCT/EP2001/010592
Authority: WO
Inventors: Franco Sartori
Original assignee: Rizzi 1857 S.P.A.
Priority date: 2001-09-13
Filing date: 2001-09-13
Publication date: 2003-03-20

Abstract

The devices according to the invention comprise two pluralities of hide presence sensors (17, 19) arranged so as to monitor the hide that enters and exits from the conveyor and processing rollers (10, 14, 15) of resetting/retaining and drying machines. A programmable control reverses the motion of the rollers and therefore the processing when a set number of sensors (17, 19) ascertains the absence of the hide while the remaining ones ascertain that the hide continues to be present in their respective monitoring regions. In this manner, the processing cycle is automated.

Description

CONTROL SYSTEM FOR HIDE PROCESSING MACHINES

Technical Field

The present invention relates to automatic devices for controlling hide processing in resetting/retaining and drying (setting out) machines, of the type used in particular to treat whole hides of cows, sheep, et cetera. Background Art

It is known that multiple passes are performed in these machines by reversing the advancement motion of the machine. Motion reversal is performed by an operator, who uses his skill and sensitivity to stop and reverse the machine when the hide has entered it almost completely but must be careful to stop the machine before the hide disengages from the feed rollers, since in this case the hide would not only be expelled from the machine, stopping the processing cycle, but it might also be damaged.

Both during the forward motion and during the return motion, it is not easy to know the exact location of the edge of the hide that is about to exit from the feed rollers.

The difficulty in knowing the position of the hide and therefore in intervening at the right time and reversing the motion arises from several factors.

A first factor is the nonuniform shape of the hide and particularly of its contour.

Another difficulty factor arises from the fact that the components of these machines are not visually accessible because of structural and safety reasons. All this entails that it is difficult to establish the exact position in which motion reversal must occur.

In this situation, the hide, as mentioned, may escape from the feed rollers or the operator, in order to keep a safety margin, may reverse the motion too soon and therefore fail to process the hide fully. Disclosure of the Invention

The aim of the present invention is to provide automatic devices for controlling the processing cycle that do not require the intervention of an operator. Within this aim, an object of the invention is to provide devices that reverse the motion when the hide has reached an end position yet has a safety margin.

Another object is to provide automatic devices in a resetting and drying machine which allow optimum processing of practically all of the hide. This aim, these and other objects which will become better apparent hereinafter are achieved by automatic devices for controlling hide processing in resetting/retaining and drying machines, comprising a hide conveyor roller, at least one presser roller, which acts on the conveyor roller, and an expansion roller which acts on a supporting roller, characterized in that they comprise a first pluraUty of hide presence sensors arranged in the insertion region and of a second plurality of hide presence sensors arranged at the exit region, said sensors activating reversal of the motion of the machine when a preset number of sensors of the first or second pluralities ascertains that the hide is not present in the monitored region, at least one angular encoder being also provided, said encoder delaying motion reversal by a certain angle after the signal indicating the absence of hide in the insertion or exit region.

Brief description of the drawings

Further characteristics and advantages of the invention will become better apparent from the detailed description of preferred embodiments thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

Figure 1 is an overall diagram of a resetting/retaining and drying machine; Figure 2 is a schematic sectional view of a resetting/retaining and drying machine shown in the step of hide insertion;

Figure 3 is a schematic sectional view of the machine of Figure 2 in the closure step;

Figure 4 is a schematic sectional view of the machine of Figure 2 in the preparation step for processing;

Figure 5 is a schematic sectional view of the machine of Figure 2 in the processing step;

Figure 6 is a schematic sectional view of the machine of Figure 2 during the initial opening that precedes hide unloading; Figure 7 is a schematic perspective view of the arrangement of the hide presence sensors;

Figure 8 is a schematic view of another embodiment of the resetting/retaining and drying machine of Figure 2. Ways to carrying out the Invention With reference to the figures, the devices according to the invention are applied to a combined resetting/retaining and drying machine, the layout of which is shown in Figure 1.

Said machine has, with reference to Figure 1, which is a diagram of its main elements, a conveyor roller 10 on which the hide to be processed is arranged; said hide is designated by the reference numeral 11 in the figures that follow.

In order to feed the hide 11 by means of the conveyor roller 10, there are two presser rollers 12 and 13, which during processing operations are kept pressed against the roller 10 by means of hydraulic pistons, designated by the reference numerals 23 and 24 in Figure 2.

An expansion roller 15 acts against the conveyor roller 10 and against an additional supporting roller 14 and is provided with a plurality of gills 16 made of stainless steel which press their bevel against the hide.

Figure 2 illustrates the step in which the hide 11 is arranged so as to straddle the conveyor roller 10, which is mounted together with the 21 which allows it to move away from the presser rollers 12 and 13 and from the expansion roller 15.

During this step, the hide is laid out manually by the operator; thereafter, as shown in Figure 3, the machine is closed, that is the conveyor roller 10 is placed against the presser rollers 12 and 13 and against the expansion roller 15.

The hide, as shown in Figure 4, is then made to advance by turning the conveyor roller 10, and its presence is detected by a first plurality of sensors 17 arranged as close as possible to the point of tangency 18 between the presser roller 12 and the conveyor roller 10.

This first group of presence sensors 17 is schematically shown more clearly in Figure 8, where said sensors are designated by the reference numerals 17a, 17b, 17c, 17d and 17e respectively.

As shown more clearly in Figure 8 by way of example, the sensors 17a and 17e do not detect the presence of the hide, while the sensors 17b, 17c and 17d detect the presence of the hide.

The program of the machine takes into account a minimum number of sensors that must always detect the presence of the hide.

When the number of sensors that detect the presence of the hide is smaller than the set number, the machine is stopped automatically and motion is reversed.

A second plurality of sensors is designated by the reference numeral 19 in Figures 3, 4, 5 and 6, and is designated by the reference numerals 19a, 19b, 19c, 19d and 19e in Figure 8; said plurality is arranged just after the exit of the expansion roller 15.

With reference to this figure, it is evident that the sensors 19a and 19e do not detect the presence of the hide, while the sensors 19b, 19c and 19d detect the presence of the hide.

In this case also, there is a minimum number of sensors that must detect the presence of the hide; if this does not occur, the motion of the machine is halted and reversed.

In the machine there is also an angular encoder 22, which as shown in Figure 4 allows the advancement of the hide by a maximum angle designated by way of example by the reference numeral 20 in Figure 4. The encoder 22 can provide for an additional angle, not shown, which allows to move the hide 11 backward, even when the sensors 19 have detected the need to stop it, by an extent which is calculated so that said hide does not escape from the grip of the expansion roller 15 and of the supporting roller 14. The devices that can be used are of various kinds and can be of the mechanical, optical, infrared, laser, or other type.

The only care that must be taken in choosing them is to make sure that they are compatible with the humid environment of the machine.

In another embodiment shown in Figure 9, the two presser rollers, now designated by the reference numerals 101 and 102, are connected by a belt 103 which allows to surround the conveyor roller 104 over a wide angle.

This allows to make the hide advance much more toward the expansion roller, now designated by the reference numeral 105.

With these automatic control systems executed according to the invention, the hide is treated perfectly along substantially all of its extension, yet the operator does not have to intervene with his skill and experience to reverse the motion of the machine.

The operator merely has to load and unload the machine, and the use of qualified personnel is not required for this task. Another very important consequent aspect is the accident-prevention aspect, since advantageously the operator no longer needs to make contact with the potentially dangerous parts of the machine.

From what has been described and illustrated, it is evident that the intended aim and the objects have all been achieved, and that in particular automatic hide position monitoring devices with machine control have been automatic hide position monitoring devices with machine control have been devised.

As mentioned, starting from the same inventive concept it is of course possible to use sensors of various types, and the position also can be chosen conveniently with reference to the machine.

The materials and the dimensions may be any according to requirements.

Claims

1. Automatic devices for controlling hide processing in resetting/retaining and drying machines, of the type that comprises a hide conveyor roller (10), at least one presser roller (12,13), which acts on the conveyor roller (10), and an expansion roller (15), which acts on a supporting roller (14), characterized in that the devices comprise a first plurality of hide presence sensors (17) arranged in the insertion region and of a second plurality of hide presence sensors (19) arranged at the exit region, said sensors activating reversal of the motion of the machine when a preset number of sensors of the first (17) or second (19) plurality of sensors ascertains that the hide is not present in the monitored region, at least one angular encoder (22) being also provided, said encoder (22) delaying motion reversal by a certain angle after the signal indicating the absence of hide in the insertion or exit region.

2. The devices according to claim 1, characterized in that said hide presence sensors that belong to said first plurality of sensors (17) are aligned as close as possible to the line of tangency (18) of the conveyor roller (10) and of the first presser roller (12) of the resetting and drying machine, on the hide insertion side.

3. The devices according to claim 1, characterized in that said hide presence sensors that belong to said second plurality of sensors (19) are aligned as close as possible to the line of tangency between said expansion roller (15) and said supporting roller (14), on the hide exit side.

4. The devices according to claim 1, characterized in that said hide presence sensors (17,19) are of the mechanical contact type.

5. The devices according to claim 1, characterized in that said hide presence sensors (17,19) are of the optical type.

6. The devices according to claim 1, characterized in that said hide presence sensors (17,19) are of the infrared type.

7. The devices according to claim 1, characterized in that said hide presence sensors (17,19) are of the laser-beam type.

8. The devices according to claim 1, characterized in that said hide presence sensors (17,19) are of the pneumatic type.

9. The devices according to claim 1, characterized in that said hide presence sensors (17,19) are programmed so than when absence of hide is ascertained simultaneously by a preset number of said devices, the motion of the machine is reversed automatically.

10. The devices according to claim 1, characterized in that they comprise an angular encoder (22) which delays reversal of the motion of the machine by a first preset angle in the advancement direction and by a second preset angle in the return direction after the reversing signals that arrive from the respective hide presence sensors (17,19).

11. The devices according to claim 1, characterized in that in a resetting/retaining and drying machine provided with two presser rollers (101,102) connected by a belt (103) which acts over a preset arc on the conveyor roller (104), the angular encoder (22) provides an angle of delay of advancement motion reversal, which is calculated with reference to the line of tangency of the second presser roller (102).