TWM456860U - Dry artificial leather manufacturing machine - Google Patents

Description

Dry artificial leather making machine

The present invention relates to a processing machine, and in particular to a dry artificial leather manufacturing machine for producing artificial leather.

As we all know, the traditional artificial leather manufacturing is divided into dry and wet. The wet type refers to mixing the raw material resin into water to make a solution, then immersing the base cloth in a solution for rolling, and after repeated immersion rolling and drying, it becomes an artificial leather. In the production process of wet-made artificial leather, a lot of waste water is generated, and the manufacturing process is complicated, and the equipment and operation cost are high. Therefore, most of the dry-type artificial leather is actually used. As the name suggests, the so-called dry artificial leather manufacturing refers to the method of applying the resin to the surface of the base fabric without rolling in the solution, but if the resin is directly applied to the surface of the base fabric, the surface of the finished product may be uneven due to the cloth. The effect of aesthetics is that the traditional dry-manufactured artificial leather process is to apply various functional resins on the surface of the release paper, and then attach it to the base fabric, and finally peel off the release paper to become a dry artificial leather.

The traditional dry artificial leather manufacturing machine is divided into a release paper sending device, a release paper receiving device, a release paper storage device for continuous production, a coating unit, a drying oven, a base cloth sending unit, and a pre-heating unit before fitting. , laminating unit, shaped oven after lamination, cooling unit before finished product, release paper stripping unit, release paper winding unit, finished winding unit, etc., the release paper passes through the release paper sending device and the release paper receiving device during production. The release paper storage device is coated with resin to the coating and coating unit, and the release paper after the blade coating is dried by hot air into the oven, and the release paper after drying enters the laminating unit, and the cloth is sent through the cloth sending device and preheated. After the device is sent to the laminating unit, the pressure-bonding of the laminating unit makes the fabric and the release-coated release paper be integrated into one body, and then dried and shaped by the fitted mold oven, after cooling and being peeled off. It becomes two layers of artificial leather and release paper, each of which is wound into a finished product. If it is necessary to scrape the resin with different functions multiple times, it is necessary to design multiple sets of coating machine and drying oven.

The traditional way of producing dry artificial leather is very large. The usual production line is about 100 meters long, mainly because of the linear oven, the inefficient air convection heating method, the separate coating, drying and laminating units. Caused by the relevant equipment of the release paper itself. The production line is too long and causes a lot of inconvenience in operation, and more operators are required.

The traditional dry artificial leather manufacturing is not only huge equipment, high energy consumption, but more importantly, it is inevitable to use a large amount of consumables - release paper, which has already become a symbolic feature of dry-made artificial leather. Usually, for every one meter of finished product, about 0.5 yuan of release paper is required. According to the calculation of 8 hours per day per machine, and 1200 meters of finished products per hour, one machine will use about 1.7 million yuan of release paper per year. From an environmental point of view, a one-meter release paper weighs about 80 grams, and a machine consumes about 276 tons of pure paper per year. The use of release paper is very disadvantageous for environmental protection and cost saving. Therefore, people have been actively seeking better ways of producing artificial leather for a long time.

The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a dry artificial leather manufacturing machine which is small in size, low in cost, high in energy utilization rate, low in noise pollution, and free from the need for a large amount of release paper consumables.

The purpose of the present invention is achieved by the following scheme: a dry artificial leather manufacturing machine, characterized in that the dry artificial leather manufacturing machine comprises a frame and a heating wheel mechanism disposed on the frame, the heating wheel mechanism comprising a scraper mechanism, a rotating heating wheel and at least one fitting wheel, the heating wheel is provided with a heating device, the outer circumferential surface of the heating wheel is a flat working surface, and the blade mechanism is disposed corresponding to the working surface of the heating wheel Above the heating wheel, the bonding wheel is disposed on a side of the heating wheel corresponding to the working surface of the heating wheel, and the bonding wheel is located in front of the blade mechanism in a rotating direction of the heating wheel.

The working surface of the heating wheel is provided with a Teflon anti-adhesion layer.

The heating wheel mechanism includes at least two applicator wheels.

The scraper mechanism includes a scraper, a retaining material structure and a pressure lifting mechanism, the scraper and the retaining material structure are located on a side of the working surface of the heating wheel, and the scraper is located in the rotating material in the rotating direction of the heating wheel The front side of the structure, and the scraper is located on the side of the material, the left and right ends of the scraper are respectively fixedly connected with a connecting structure, the connecting structure fixedly connected by the left and right ends of the scraper and the pressure lifting mechanism Connected, the pressure lifting mechanism is coupled to the frame.

A compensation wheel is connected to each of the left and right ends of the scraper.

The connecting structure is provided with a height adjusting mechanism provided with a longitudinally extending lifting frame, and a lower side of the lifting frame is provided with a compensation wheel.

The pressure elevating mechanism includes a cylinder, a sliding block, and a slide rail disposed on the frame, the cylinder includes a piston rod, the sliding block is fixedly coupled to a piston rod of the cylinder, and the sliding block is The slide rail is slidably connected, and the sliding block is fixedly connected to the connecting structure.

The dry artificial leather manufacturing machine is also provided with a winding mechanism for winding the finished product.

The dry artificial leather manufacturing machine is also provided with a unwinding mechanism for providing a base tape.

The heating wheel mechanism is continuously provided with at least two.

The advantages of this creation are:

First, since the surface of the heating wheel in this creation is smoothed, the surface of the artificial leather produced by this method is also smooth. Since the creation is based on a heating wheel, it is not necessary to produce a dry artificial leather by this method. The release paper, that is to say, the heating wheel replaces the release paper used in the conventional method, and the heating wheel can be used for a long time. This is very beneficial for cost savings and environmental protection.

Secondly, the heating and drying (or foaming) of the traditional dry artificial leather manufacturing machine is carried out in a very long oven. As is known, the heat transfer mainly includes conduction, convection and radiation, and the general heat transfer comes. It is said that the direct contact conduction is much higher than the air convection efficiency. Because the creation uses the heating wheel to directly heat, instead of the traditional machine oven, the hot air convection heating method greatly reduces the conduction efficiency, and the environmental protection and energy saving effect is obvious. The thermal energy of the dry artificial leather manufacturing machine was reduced from about 1,300,000 Kcal/h to about 300,000 Kcal/h. At the same time, because the creation uses the heating wheel to directly contact the heat conduction method, the conventional air convection heating method is not required, thereby avoiding the noise brought by the fan and greatly improving the production environment of the operator.

Furthermore, since the creation of the heating and transporting of the paint and the base strip can be accomplished by the heating wheel, the doctor mechanism and the laminating wheel for the uniform coating are distributed on the circumferential surface of the heating wheel, and the The scraping equipment, heating equipment, transmission equipment, laminating equipment and sizing equipment in the traditional process are combined on a heating wheel mechanism, and a heating wheel is shared by the scraping, heating, conveying, laminating and shaping processes, in the coating and the base material. The process of passing the heating wheel mechanism can complete the five steps of scraping, heating, transferring, laminating and shaping of the coating and the base strip, which greatly simplifies the mechanical structure and saves costs. At the same time, as this creation will change the traditional linear transmission method in the process of scraping, heating, conveying, laminating and shaping of coatings and base belts into ring transmission, which greatly shortens the length of the production line and makes the artificial leather production line. The length of the original is reduced from about 100 meters to about 20 meters, which also reduces the occupation of the site and effectively overcomes the problem that the tension caused by the complexity of the transmission mechanism is difficult to control. The above structure also makes the creation easier to operate, using fewer operators.

(1)‧‧‧Rack (2)‧‧‧Heating wheel mechanism (3)‧‧‧Scraper (4)‧‧‧Removal structure (5)‧‧‧heating wheel (6)‧‧‧ fitting wheel (7) ‧ ‧ heating cover (8) ‧ ‧ exhausting device (9) ‧ ‧ release paper unwinding mechanism (10) ‧ ‧ release paper winding mechanism (11) ‧ ‧ rewinding mechanism (12 )‧‧‧Cooling wheel set (13)‧‧‧ Unwinding mechanism (14)‧‧‧Base belt (15)‧‧‧ Embossing mechanism (16)‧‧‧Disintegration device (17)‧‧‧ Cut Edge installation (18) ‧ ‧ storage rack (19) ‧ ‧ fabric preheating device (20) ‧ ‧ release paper tape (21) ‧ ‧ mounting bracket (22) ‧ ‧ compensation wheel (23) ‧ ‧ ‧ Pressure lifting mechanism (24) ‧ ‧ connection structure (25) ‧ ‧ height adjustment mechanism (26) ‧ ‧ lifting frame (27) ‧ ‧ coating (28) ‧ ‧ coating

Fig. 1 is a schematic view showing the structure of a dry artificial leather manufacturing machine of the present invention.

Fig. 2 is a partial enlarged view of Fig. 1.

Fig. 3 is a schematic view showing the structure of the first embodiment of the dry artificial leather manufacturing machine of the present invention.

Fig. 4 is a schematic view showing the structure of a second embodiment of the dry artificial leather manufacturing machine of the present invention.

Fig. 5 is a schematic view showing the structure of a third embodiment of the dry artificial leather manufacturing machine of the present invention.

Fig. 6 is a schematic view showing the structure of a fourth embodiment of the dry artificial leather manufacturing machine of the present invention.

Fig. 7 is a schematic view showing the structure of a fifth embodiment of the dry artificial leather manufacturing machine of the present invention.

Fig. 8 is a schematic view showing the structure of a sixth embodiment of the dry artificial leather manufacturing machine of the present invention.

Fig. 9 is a schematic view showing the structure of a seventh embodiment of the dry artificial leather manufacturing machine of the present invention.

In order to provide the Applicant with a better understanding of the structure, features and other objects of the present invention, the following detailed description is provided with the following detailed description, but the embodiments illustrated in the drawings are for illustrative purposes. It is not the only restriction on patent applications.

As shown in FIG. 1 and FIG. 3, a dry artificial leather manufacturing machine includes a frame (1), a heating wheel mechanism (2) disposed on the frame (1), and a heating wheel mechanism (2) including a blade mechanism and a rotation. The moving heating wheel (5) and the bonding wheel (6), the heating wheel (5) is provided with a heating device for providing heat, the outer circumferential surface of the heating wheel (5) is a flat working surface, and the blade mechanism corresponds to heating The working surface of the wheel (5) is disposed above the heating wheel (5), and the working surface of the bonding wheel (6) corresponding to the heating wheel (5) is disposed beside the heating wheel (5), and the fitting wheel (6) Located in front of the doctor mechanism in the direction of rotation of the heating wheel (5).

Wherein, the scraper mechanism comprises a scraper (3) and a retaining material structure (4), the scraper (3) is located in front of the retaining material structure (4) in the rotating direction of the heating wheel (5), and the scraper (3) is located in the retaining material structure Side of (4). The heating wheel mechanism (2) includes two fitting wheels (6). The dry artificial leather manufacturing machine is further provided with a winding mechanism (11) and a unwinding mechanism (13) for providing the base tape (14), and the bonding wheel (6) passes through the base tape (14) and the unwinding mechanism (13). )connection. In order to better separate the product from the heating wheel (5), the present embodiment provides a Teflon release layer on the surface of the heating wheel. As shown in the third figure, the scraper (3) is mounted by the mounting bracket (21) beside the working surface of the heating wheel (5). The heating wheel (5) is a wheel having a heat conducting function, and the heating device is a device that can supply steam, heat transfer oil or hot air to the inside of the heating wheel (5), or can be a kind of electricity disposed inside the heating wheel (5). heating equipment.

During work, the operator pours the paint (27) between the heating wheel (5), the material structure (4), and the doctor blade (3), while the heating wheel (5) rotates, the doctor blade (3) makes the paint (27). Uniformly distributed on the working surface of the heating wheel (5) to form a coating (28), then the coating (28) is carried forward by the heating wheel (5) and is transferred by the heating wheel (5) Heating and drying, at the same time, the heating wheel (5) and the bonding wheel (6) drive the base belt (14) to move forward, and the bonding wheel (6) will coat the coating (28) with the base material. (14) Pressing into one, and then heating, drying, and shaping after heating wheel (5) to obtain the finished product.

Of course, in this creation, only one laminating wheel (6) can be provided on the working surface of the heating wheel (5). Since the coating (27) has a certain viscosity, the coating (27) is formed after passing through the doctor blade (3). The coating (28) will conform to the working surface of the heating wheel (5) and move forward with the heating wheel (5), passing the coating wheel (6) through the bonding wheel (6) and the base tape (14). After bonding, the composite formed by the coating (28) and the base tape (14) still adheres to the working surface of the heating wheel (5), and functions to heat and shape until winding.

In this creation, the diameter of the heating wheel (5) can be 1.2 meters. Of course, other diameter heating wheels (5) can also be used, but in order to meet the requirements of heating and drying the coating (27), the diameter of the heating wheel (5) The smaller it is, the slower it will spin. Similarly, the larger the diameter of the heating wheel (5), the faster the rotation speed and the higher the production efficiency.

First embodiment

As shown in Fig. 3, the left and right ends of the scraper (3) are respectively provided with a first mandrel, the first mandrel is connected with a compensating wheel (22) through a bearing, and the connecting structure of the scraper (3) is fixedly connected through the left and right ends. (24) is connected to the pressure lifting mechanism (23), which is connected to the frame (1).

The pressure lifting mechanism (23) comprises a cylinder, a sliding block and a sliding rail disposed on the frame (1), the cylinder comprises a piston rod, the sliding block is fixedly connected with the piston rod of the cylinder, and the sliding block is slidably connected with the sliding rail, and the sliding block is The connection structure (24) is fixedly connected.

Since the prior art is difficult to process the concentricity of the large-diameter heating wheel, and after long-term heating, the heating wheel is deformed, resulting in uneven coating thickness.

Therefore, the compensation wheel (22) is pressed against the working surface of the heating wheel (5) by the pressure lifting mechanism (23), and the thickness of the coating (28) is between the working surface of the doctor blade (3) and the heating wheel (5). The clearance determines that the compensation wheel (22) is always pressed against the working surface of the heating wheel (5), that is to say that the compensation wheel (22) and the heating wheel (5) are always in a phase-matching state, which makes The gap between the scraper (3) and the working surface of the heating wheel (5) is determined by the diameter of the compensating wheel (22). Since the compensating wheel (22) is small, the diameter of the compensating wheel (22) is easier to achieve concentricity. High, during the rotation of the heating wheel (5), when the concentricity of the heating wheel (5) is not good, the diameter of the heating wheel (5) is inconsistent, the structure can maintain the blade edge of the blade (3) and the heating wheel (5) The gap between the working faces is always the same, so the thickness of the produced coating (28) is always the same in the length direction of the product.

To obtain a different coating (28) thickness, simply adjust the distance between the tangent point between the compensation wheel (22) and the working surface of the heating wheel (5) and the edge of the doctor blade (3). To adjust this distance, a way to replace the compensation wheel (22) of different diameters can be taken.

Second embodiment

As shown in FIG. 4, the left and right ends of the scraper (3) are respectively fixedly connected with a connecting structure (24), and the connecting structure (24) is provided with a height adjusting mechanism (25), and the height adjusting mechanism (25) is provided with a longitudinal extension. The lifting frame (26), the lower part of the lifting frame (26) is provided with a second mandrel, the second mandrel is connected with a compensation wheel (22) through a bearing, and the connecting structure of the blade (3) is fixedly connected by the left and right ends (24) ) is connected to a pressure lifting mechanism (23) that is coupled to the frame (1).

The pressure lifting mechanism (23) comprises a cylinder, a sliding block and a sliding rail disposed on the frame (1), the cylinder comprises a piston rod, the sliding block is fixedly connected with the piston rod of the cylinder, and the sliding block is slidably connected with the sliding rail, and the sliding block is The connection structure (24) is fixedly connected.

To obtain a different coating (28) thickness, simply adjust the distance between the tangent point between the compensation wheel (22) and the working surface of the heating wheel (5) and the edge of the doctor blade (3). The height of the compensating wheel (22) relative to the frame (1) can be adjusted by retracting or lowering the lifting frame (26) by the height adjusting mechanism (25), thereby changing the working surface of the heating wheel (5) and the scraper (3) The distance between the edges of the knife.

Third embodiment

In the present embodiment, a heating cover (7), a storage rack (18), a cooling wheel set (12), and an exhausting device (8) are added to the above.

As shown in Fig. 5, an auxiliary heating cover (7) is added to the outside of the heating wheel to improve the heating and drying effects. In order to improve the speed and the degree of automation, the present embodiment adds a storage rack (18) for replacing the discharge roll without stopping the machine, and a cooling wheel is added between the heating wheel mechanism (2) and the winding mechanism (11). Group (12). Since some of the coatings (27) contain volatile solvents, the present embodiment adds an exhausting device (8). In actual production, the exhaust gas device (8) is connected to the solvent recovery device to facilitate environmental protection.

Fourth embodiment

In the actual production process, adjust the gap between the scraper (3) and the heating wheel (5), you can set the thickness of the desired coating (27) layer, but when the required coating (27) layer thickness is thicker, by adjusting When the gap between the doctor blade (3) and the heating wheel (5) is not satisfied, it is necessary to continuously provide two or more heating wheel mechanisms (2). In the production process of artificial leather, in order to obtain artificial leather with better performance, it is necessary to sequentially process two different heating coatings (28) when processing the coating (28) of different materials on the base belt (14). .

As shown in Fig. 6, in the present embodiment, three heating wheel mechanisms (2) are continuously provided, and each of the heating wheels (5) of the heating wheel mechanism (2) is provided with a plurality of bonding wheels (6). The coating (27) passes through three heating wheel mechanisms (2) in order so that the base tape (14) and the coating (27) can be better fitted. When the same coating (27) is added to the material structure (4) of the three heating wheel mechanisms (2), the artificial leather having a thick coating layer (27) is finally obtained; when the three heating wheel mechanisms (2) When three different coatings (27) are added to the baffle structure (4), an artificial leather having three layers of different coatings (27) is finally obtained, which has better properties.

In the present embodiment, an embossing mechanism (15), a film releasing device (16), a cooling wheel group (12), and a trimming edge are disposed between the winding mechanism (11) and the third heating wheel mechanism (2). The device (17), after the paint (27) belt comes out from the third heating wheel mechanism (2), is transported by the guide wheel to the embossing mechanism (15) after embossing, and then cooled, trimmed and rolled. The finished product, the finished leather finished product has a more diversified surface. At the same time, a storage rack (18) and a fabric preheating device (19) are disposed between the first heating wheel mechanism (2) and the unwinding mechanism (13).

In addition, in the present creation, an automatic edge-aligning device, a tension control device, and a heating wheel cleaning device can be added to achieve an effect of further improving the performance and automation of the machine. In order to make the operator more convenient in the present embodiment, the frame (1) is also provided with stairs and handrails.

Fifth embodiment

When we need to obtain a more comprehensive artificial leather such as a finished leather product having a four-layer effect layer of a top layer, a filling layer, a foam layer, and a contact agent layer or to obtain a thicker artificial leather product, as shown in the seventh figure, this embodiment A heating wheel mechanism (2) is added to the third embodiment, and a plurality of bonding wheels (6) are provided on the heating wheel (5) of each heating wheel mechanism (2) for the base belt (14) It can be better fitted with the coating (27). Meanwhile, the cloth preheating device (19) and the trimming device (17) are not provided in this embodiment.

Sixth embodiment

As shown in Fig. 8, in order to pursue the surface effect of the conventional release paper product in actual production, the release paper must be used in the production process of some products. Therefore, in the present embodiment, a release paper unwinding mechanism (9) is further disposed on the side of the heating wheel (5), and the release paper unwinding mechanism (9) passes through the release paper tape (20) and the heating wheel (5). The connection is further provided with a release paper winding mechanism (10) on the side of the winding mechanism (11). In the case where it is necessary to use a release paper for production processing, the dry artificial leather manufacturing machine in this embodiment can still be used.

In operation, the release paper is fed between the doctor blade (3) and the heating wheel (5) by the release paper unwinding mechanism (9), and the coating material (27) is placed at the material blocking structure (4), the doctor blade (3) The paint (27) is evenly distributed on the release paper, and then adhered to the base tape (14) through the bonding wheel (6) after proper drying of the heating wheel (5), and is heated and shaped by the heating wheel (5). After being conveyed to the cooling mechanism for cooling, after the release paper is peeled off from the artificial leather product, the release paper and the artificial leather product are each wound up.

Of course, the fifth embodiment can also provide a plurality of heating wheel mechanisms (2) as in the third embodiment and the fourth embodiment.

Seventh embodiment

As shown in Figure 9, this creation is also applicable to the dermal filming process. When the base tape (14) is dermis, it is only necessary to change the original substrate to the dermis. Meanwhile, in the present embodiment, the unwinding mechanism (13) and the winding mechanism (11) are not used, and the two-step action can be performed manually. In the present embodiment, an exhausting device (8) is also provided.

Of course, in the seventh embodiment, a conveying device and a receiving device suitable for the dermis can be added. When the base tape (14) is not dermis, the unwinding and winding of the base tape (14) can also be done manually.

In addition, the scraper (3) can be selected in different ways, such as sharp knife, round knife, "J"-shaped scraper (3), scraper (3) gap adjustment can also be selected in different ways, as long as the purpose of adjusting the gap can be achieved, It will not be elaborated here. Furthermore, since the production of artificial leather has two processes of dry sticking and wet sticking, the bonding place of the base strip (14) and the coating (27) can be set in the position immediately next to the scraper (3) according to different requirements, so that the coating is made. (27) The film may be attached in a semi-dry state, or may be disposed at a position spaced apart from the blade (3) in front of the blade (3) to allow the coating (27) to be adhered in a fully dry state. Of course, it is also possible to provide a plurality of fittings composed of the bonding wheels (6) on the same machine to meet different process requirements.

In summary, this creation can indeed achieve the above functions and purposes, so this creation should meet the requirements of the patent application, and apply in accordance with the law.

(1)‧‧‧Rack

(11) ‧‧‧Winding agencies

(13) ‧‧‧ Unwinding agency

(14) ‧‧‧Base belt

(3)‧‧‧Scraper

(4) ‧‧‧block structure

(5) ‧‧‧heating wheel

(6) ‧‧‧Fitting wheel

Claims (10)

A dry artificial leather manufacturing machine, characterized in that the dry artificial leather manufacturing machine comprises a frame and a heating wheel mechanism disposed on the frame, the heating wheel mechanism comprising a scraper mechanism, a rotating motion heating wheel and at least one fitting wheel, The heating wheel is provided with a heating device, the outer circumferential surface of the heating wheel is a flat working surface, and the working surface of the scraping mechanism corresponding to the heating wheel is disposed above the heating wheel, and the fitting wheel corresponds to The working surface of the heating wheel is disposed on a side of the heating wheel, and the bonding wheel is located in front of the blade mechanism in a rotating direction of the heating wheel. The dry artificial leather manufacturing machine according to claim 1, wherein the working surface of the heating wheel is provided with a Teflon anti-adhesion layer. The dry artificial leather manufacturing machine according to claim 1, wherein the heating wheel mechanism comprises at least two bonding wheels. The dry artificial leather manufacturing machine according to claim 1, wherein the scraper mechanism comprises a scraper, a retaining material structure and a pressure lifting mechanism, wherein the scraper and the retaining material structure are located on a working surface of the heating wheel. On the side of the scraper, the scraper is located in front of the retaining material structure in the direction of rotation of the heating wheel, and the scraper is located on the side of the retaining material structure, and the left and right ends of the scraper are respectively fixedly connected with a connecting structure The scraper is connected to the pressure lifting mechanism by a connecting structure fixedly connected at both left and right ends, and the pressure lifting mechanism is connected to the frame. The dry artificial leather manufacturing machine according to the fourth aspect of the invention is characterized in that: the compensation wheel is connected to the left and right ends of the scraper. The dry artificial leather manufacturing machine according to claim 4, wherein the connecting structure is provided with a height adjusting mechanism, the height adjusting mechanism is provided with a longitudinally extending lifting frame, and the lower side of the lifting frame is provided with a compensation wheel . The dry artificial leather manufacturing machine according to claim 4, wherein the pressure lifting mechanism comprises a cylinder, a sliding block and a slide rail disposed on the frame, the cylinder includes a piston rod, and the sliding The block is fixedly coupled to the piston rod of the cylinder, and the sliding block is slidably coupled to the sliding rail, and the sliding block is fixedly coupled to the connecting structure. The dry artificial leather manufacturing machine according to any one of claims 1 to 4, wherein the dry artificial leather manufacturing machine is further provided with a winding mechanism for winding the finished product. The dry artificial leather manufacturing machine according to any one of claims 1 to 4, wherein the dry artificial leather manufacturing machine is further provided with a unwinding mechanism for providing a base tape. The dry artificial leather manufacturing machine according to any one of claims 1 to 4, wherein the heating wheel mechanism is continuously provided with at least two.