CN111406120A - Improved pull-softening machine - Google Patents

Abstract

An improved staking machine (1) for softening and stretching flexible sheet products having opposite sides, such as industrial hides and the like, comprising motorized feeding means (5) for conveying the products in a predetermined longitudinal direction (L), at least one pair of striking plates (10, 10') facing each other, substantially parallel to the feeding means (5) and acting on opposite sides of the products, one plate (10) being fixed and the other (10') being movable and connected to motor means (11) which transmit thereto a reciprocating movement with a predetermined number of strikes per minute, the machine (1) comprising means (23) for adjusting the working pressure between the fixed plate (10) and the movable plate (10'), which selectively act on the fixed plate (10) to vary the mutual distance between the fixed plate (10) and the movable plate (10'), the machine (1) also comprising electronic control means (24) acting on the motor means (11) to vary the number of strikes of the movable plate (10') continuously during the initial and steady-state operations of the products (10') according to the type and to the desired characteristics of the products to be treated.

Description

Improved pull-softening machine

technical field

The present invention generally finds application in the field of tanning equipment, and in particular relates to an improved stretch-softening machine for flexible sheet products.

Background technique

Machines known as stretch softeners have long been known in tanneries for softening and stretching flexible sheet products such as industrial hides and similar products having opposite sides (ie, grain and meat).

These machines are used in the post-tanning and/or drying steps to restore the original softness of the leather and increase its size, ie the useful leather area.

Typically, these machines comprise a motorized feeding device for feeding the product in a predetermined direction, for example consisting of a pair of mutually facing conveyor belts, between which the sheet product to be softened is inserted.

These machines also include one or more pairs of pads facing each other parallel to the longitudinal direction. The plates reciprocate to move toward and away from each other substantially perpendicular to the product supply plane.

Additionally, each plate has a tool or peg adapted to interact with a corresponding mating formed cavity or recess on the opposing plate.

EP2049694 by the owner of the present invention discloses a perching machine comprising at least one fixed plate and a movable plate for adjusting the mutual distance between the two plates associated with the device.

These adjustment devices can adjust the pull-softening pressure on the opposite sides of the hide to adjust the product finish.

Although the machine can perform its intended task satisfactorily, it can still be improved, i.e. in terms of increasing the efficiency and productivity of the machine.

The useful leather area and softness of a flexible sheet product is directly dependent on the feed speed through the machine and the number of blows per minute of the strike plate.

Nonetheless, the rate of supply of product can be adjusted within a limited range that is directly related to the rate of supply of product in the production line and is proportional to the production rate.

To at least partially eliminate this disadvantage, machines have been developed that can adjust the strokes per minute of the reciprocating motion of the movable plate.

The number of blows is usually varied by adjusting the speed ratio between the motor and the drive shaft that transmits motion to the movable plate.

Nonetheless, due to the considerable mass of the pads, this adjustment can only be done discretely and with the machine turned off, which increases processing time and reduces the work factor.

An additional disadvantage of this setup is that it requires manual adjustment by the operator, which increases the complexity and labor intensity of the adjustment procedure.

Another disadvantage of this arrangement is that, in order to adjust the speed ratio, the operator has to manually access mechanically moving parts that are usually located in inaccessible locations below the feed device.

EP0829543 and CN104746352 disclose stretch softening machines as defined in the preamble of claim 1 for softening and stretching flexible sheet products.

technical problem

In view of the prior art, the technical problem solved by the present invention is to provide a soft-pulling machine capable of more effective and immediate adjustment of the number of blows, so that the machine can be adapted in time to the various types of products to be processed and the needs product characteristics.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate the above disadvantages by providing an improved stretch softening machine for softening and stretching flexible sheet products, which is efficient and relatively cost-effective.

A particular object of the present invention is to provide an improved soft-pulling machine as described above, capable of continuously adjusting the strokes per minute of one or more movable plates.

Another object of the present invention is to provide an improved soft-pulling machine as described above, which is capable of reducing power consumption at startup.

A further object of the present invention is to provide an improved stretch-softening machine as described above which is capable of significantly reducing the processing time of the whole flexible sheet product.

Another object of the present invention is to provide a machine as described above, which can easily reduce the number of strikes of the board within a wide adjustment range.

A further object of the present invention is to provide a machine as described above which is highly flexible and allows the number of blows to be adjusted according to the feeding speed of the sheet product.

As explained more clearly hereinafter, these and other objects are achieved by an improved stretch softening machine as defined in claim 1 for softening and stretching flexible sheet products such as industrial hides and the like having opposite sides , the machine comprises a motorized feeding device for conveying the product in a predetermined longitudinal direction, at least one pair of striking plates facing each other, the at least one pair of striking plates being substantially parallel to the feeding device and acting on opposite sides of the product , one of the plates is fixed and the other is movable.

The machine also includes: motor means associated with the movable plates in each pair for imparting to the movable plates reciprocating motion having a predetermined number of blows per minute; and for adjusting work between the fixed and movable plates A means of pressure that selectively acts on the fixed plate to change the mutual distance between the fixed and movable plates.

In a unique aspect of the present invention, the machine includes electronic control means acting on the motor means to continuously vary the movable movement during initial start-up and during steady state operation depending on the type of product to be processed and the characteristics of the desired product The number of blows per minute of the reciprocating motion of the board.

Advantageous embodiments of the invention are obtained from the dependent claims.

Description of drawings

Additional features and advantages of the present invention will become more apparent after reading the detailed description of a preferred non-exclusive embodiment of an improved stretch softening machine for softening and stretching flexible sheet products, which embodiment is appended Described by way of non-limiting example with the help of figures, in the accompanying drawings:

1 is a perspective view of a softening machine of the present invention;

Figure 2 is a side view of the machine of Figure 1;

Figures 3 and 4 are cut-away side views of the machine of Figure 1;

Figure 5 is a cutaway top view of the machine of Figure 1 showing the drive system;

6 and 7 are first and second block diagrams of control of the machine of FIG. 1 .

Detailed ways

Referring to the preceding figures, there is shown an improved stretch softening machine for softening and stretching a flexible sheet product (not shown) having opposite sides, such as industrial hides, which is generally represented by the accompanying figures Mark 1 indicates.

The stretch-softening machine 1 comprises a carrier structure 2 adapted to define an inlet area 3 and an outlet area 4 for the sheet product and a motorized vehicle for conveying the sheet product in a predetermined longitudinal direction L from the inlet area 3 to the outlet area 4 supply device 5.

As known per se, the feeding device 5 may comprise a pair of endless upper and lower conveyor belts 6 , 7 tensioned by at least one pair of end rollers 8 , 8 ′, 9 , 9 ′.

The pair of conveyor belts 6, 7 may have respective substantially straight and horizontal portions 6', 7' facing each other to hold the sheet product introduced into the inlet area 3 of the machine 1 towards the outlet Zone 4 supplies.

The machine 1 also comprises at least one pair of striking plates 10, 10' facing each other, which are substantially parallel to the feeding device 5 and which act on opposite sides of the product being processed.

The upper plate 10 is fixed and the lower plate 10 ′ is movable and connected to the motor means 11 . The motor device 11 transmits a reciprocating motion to the movable plate 10' to move the movable plate toward or away from the fixed plate 10 at a predetermined number of strokes per minute.

The fixed upper plate 10 may include a plurality of peg tools (not shown), while the movable lower plate 10' may include a plurality of mating shaped cavities or holes (also not shown) aligned with the pegs out).

During striking, the plates 10, 10' interact due to the pegs and holes to exert a predetermined value of pressure on the sheet product as it is fed.

Obviously, the tools may also be different or have a different arrangement, ie the holes are formed in the fixed plate 10 and the pegs are formed in the movable plate 10' without departing from the scope of the present invention.

Advantageously, a plurality of plates 10 , 10 ′, 10 ″ and 12 , 12 ′, 12 ″ can also be provided in the longitudinal direction L of the sheet product, which plates are in the straight portion 6 ′ of the aforementioned conveyor belts 6 , 7 , 7' acts on the conveyor belts 6 and 7.

For example, in the intended and non-limiting embodiment of the drawings, two sets of panels 10A, 12A may be provided, each comprising a pair of fixed upper panels 10, 10" and a movable lower panel, respectively, which are secured to the load-bearing structure 2. Plate 10' and a pair of fixed upper plates 12, 12" and a movable lower plate 12'.

As best shown in Figure 5, the motor arrangement 11 preferably comprises a first electric motor 13, preferably a three-phase asynchronous, connected to the movable plates 10', 12' via a drive mechanism 14 and crank and linkage systems 15, 16 etc. motor.

That is, the movable lower plates 10 ′, 12 ′ are mounted on the upper end 17 of the connecting rod 15 , which in turn is moved by the corresponding crank 16 , which is coupled to the motor via the drive mechanism 14 13 on the shaft 18.

As known per se, the drive mechanism 14 may include one or more drive belts 19, and the crank 16 may have a circular cam.

In the embodiment shown, the second set of plates 12A also includes crank and linkage systems 15', 16'.

The latter is coupled to the crank 16 of the first set of plates 10A via a further drive mechanism 20 , preferably constituted by a toothed conveyor belt 21 .

Thus, the second set of plates 12a is driven relative to the first set 10A and its reciprocation is synchronized with the reciprocation of the plates 10, 10', 10" of the first set 10A.

Suitably, at least one second three-phase asynchronous electric motor 22 independent of the first motor 13 may be provided and coupled to the rollers 8 , 9 for moving the conveyor belts 6 , 7 at least one of the.

As shown in Figure 2, the machine 1 also comprises means 23 for adjusting the working pressure between the fixed plate and the movable plate. The adjustment device 23 acts on the fixed plates 10, 12 and changes its distance from the movable plates 10', 12'.

The adjustment means 23 may be of a known type, eg of the type described and shown in European patent EP2049694 of the owner of the present invention.

In a unique aspect of the present invention, the machine 1 includes electronic control means 24 acting on the motor means 11 of the striking pads 10, 10' to continuously vary the reciprocation of the movable paddle 10' or the movable paddle 12' Strikes per minute of movement.

In particular, the control device 24 may vary the number of blows during initial startup and steady state operation depending on the type of product to be processed and the characteristics of the desired product.

The control means 24 may comprise a PLC control unit 25 operatively connected to a first inverter 26 adapted to power the first three-phase asynchronous motor 13 .

Advantageously, the control device 24 may comprise a second inverter 27 operatively connected to the PLC control unit 25 and adapted to control the operation of the second electric motor 22 of the supply device 5 .

Therefore, the rotational speed of the second electric motor 22 and the corresponding feeding speed of the conveyor belts 6, 7 can be varied according to the characteristics of the desired product in combination with the number of blows of the movable plates 10', 12'.

In addition, the control device 24 enables independent and continuous adjustment of the striking masses 10, 10', 10" and 12, 12', 12" and the feeding device 5 without a step change in speed, so as not to shut down the machine 1 to effectively provide softened and stretched sheet products or change their productivity.

The control algorithm 28 may be installed in the PLC control unit 25, and the PLC control unit 25 may be programmed to control the first inverter 26 to cause the first electric motor 13 to pass a torque equal to the maximum torque during start-up of the first electric motor 13. Torque operates at constant flow.

That is, for frequency values less than the nominal value of the mains frequency (equal to 50 Hz), the constant flow of the first motor 13 during start-up is regulated by the first inverter 26 .

Accordingly, the first motor 13 may be operated with acceleration ramps having a predetermined duration during which the first inverter 26 provides a time-modulated voltage and frequency to the first motor 13 .

With this configuration, the power consumption of the machine 1 during start-up can be reduced and a motor with a lower power rating can be used.

Therefore, the first motor 13 can be appropriately sized for steady state operation and need not be specifically sized for start-up, and a smaller magnetocaloric switch can be installed because the current peaks are reduced.

Furthermore, the PLC control unit 25 and the first inverter 26 may be configured to allow selection of the movable plate 10' or the movable plate 10' within the range of 200 to 900 blows/min, preferably 250 to 800 blows/minute , 12' hits.

Advantageously, sensor means 29 may be associated with the drive mechanism 14 to detect the actual number of strikes of the movable plate 10 ′ or the movable plates 10 ′, 12 ′ and transmit the corresponding electrical signal E to the PLC control unit 25 .

The sensor means 29 are adapted to detect the rotation of the mechanism 14 and generate a corresponding electrical signal E, and may comprise, for example, optical or mechanical encoders or other similar sensors.

The control device 24 may include an interface device 30 that the operator can access to set the desired number of blows, and the control unit 25 may be programmed to use the installed algorithm 28 to compare the desired number of blows B with possibly filtering by suitable software. The filtered electrical signal E by the device F is continuously compared.

Furthermore, the PLC control unit 25 is configured to send a corresponding control signal C to the first inverter 26 which controls the operation of the first motor 13, thereby reducing current draw during start-up.

Suitably, the softening machine 1 may comprise a switchboard 31 adapted to receive power from the mains N and operatively connected to the PLC control unit 25 . The PLC control unit 25 may communicate with the interface device 30, the sensor device 29, the first inverter 26 and the second inverter 27 via cables to transmit the signal 32 using the MODBUS communication protocol or the like.

The closed-loop control scheme using the sensor 29 is shown in the block diagram of FIG. 6 , while the control by the algorithm 28 of the control unit 25 is shown in the block diagram of FIG. 7 .

As can be appreciated from the foregoing, the improved pull-softening machine achieves the intended purpose, and in particular enables more efficient and immediate adjustment of the number of blows and makes the machine easily adaptable to the various types of products to be treated and desired products characteristics.

The stretch softening machine of the present invention is capable of many changes and modifications within the inventive concept disclosed in the appended claims.

Although the machine has been described with particular reference to the drawings, the reference numerals mentioned in the disclosure and claims are used only for a better understanding of the invention and are not intended to limit the scope of the protection in any way.

Industrial Applicability

The present invention has industrial application as it can be produced on an industrial scale in leather and hide processing plants.

Claims (10)

1. An improved stretch-softening machine (1) for softening and stretching flexible sheet products such as industrial hides and the like having opposite sides, said machine (1) comprising: - a motorized feeding device (5) for feeding said product in a predetermined longitudinal direction (L); - at least one pair of striking plates (10, 10') facing each other, said at least one pair of striking plates being substantially parallel to said feeding means (5) and acting on opposite sides of the product, one of said plates (10) ) is fixed and the other (10') is movable; - motor means (11) associated with the movable plate (10') of said at least one pair (10, 10') to deliver to said movable plate (10') blows with a predetermined stroke per minute Reciprocating movement of numbers; - means (23) for adjusting the working pressure between said fixed plate (10) and said movable plate (10'), said means selectively acting on said fixed plate (10) to change the mutual distance between the fixed plate (10) and the movable plate (10'); Characterized in that it comprises electronic control means (24) acting on said motor means (11) for continuous operation during initial start-up and during steady state operation according to the type of product to be processed and the characteristics of the desired product The number of blows per minute of the reciprocating motion of the movable plate (10') can be changed substantially. 2. Machine according to claim 1, characterised in that the motor arrangement (11) comprises at least one first electric motor (13) via a drive mechanism (14) and a crank and A linkage system (15, 16) etc. is connected to the movable plate (10'). 3. Machine according to claim 2, characterized in that the at least one first motor (13) is a three-phase asynchronous electric motor. 4. Machine according to claim 3, characterised in that the control means (24) comprises a PLC control unit (25) operatively connected to a A first inverter (26) powered by the motor (13). 5. The machine of claim 4, wherein the PLC control unit (25) and the first inverter (26) are configured to allow between 200 and 900 blows/minute . The number of blows of the movable plate (10') is preferably selected within the range of 250 to 800 blows/min. 6. Machine according to claim 4, characterised in that the PLC control unit (25) is programmed to control the first inverter (26) such that the first inverter operates at the The first electric motor (13) operates at constant flow with a torque equal to the maximum torque during start-up. 7. Machine according to claim 4, characterized in that it comprises sensor means (29) associated with the drive mechanism (14) to detect the actual strike of the movable plate (10') and transmit the corresponding electrical signal (E) to the PLC control unit (25). 8. Machine according to claim 7, characterised in that the PLC control unit (25) comprises interface means (30) designed to be accessed by the operator to set the desired number of blows (B) , said PLC control unit (25) is programmed to continuously compare said desired number of blows (B) with said electrical signal (E) possibly filtered by a suitable algorithm (28), and report to said The first inverter (26) sends a control signal (C) to reduce current draw during start-up. 9. Machine according to claim 4, characterised in that the feeding means (5) comprise a pair of endless belt conveyors tensioned by at least one pair of end rollers (8, 8'; 9, 9') Machines (6, 7), at least one of said rollers (8, 9) being coupled to at least one second three-phase asynchronous electric motor (22) independent of said first electric motor motor (13). 10. The machine of claim 9, wherein the control device (24) comprises a second inverter (27) operatively connected to the PLC control unit ( 25) and adapted to control the operation of said second electric motor (22) to continuously vary the rotational speed of said second electric motor and correspondingly said belt conveyor (6, 7) supply speed.

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