Method for the production of rubber tracks with positive drive for agricultural machinery

Abstract

(57) In the developed method, a pre-vulcanized carcass is used, in the production of which, the compression is carried out between two planar surfaces of a press mould, which keeps the metal ropes and the protective layers of the carcass evenly spaced in all planes. This significantly increases the stability of the drive buffers and increases their useful life. When the carcass ropes are evenly spaced in all planes during operation, all ropes work with the same tension and the length of the metal ropes does not change. They are evenly distributed in all planes and the displacement in the central part described above does not occur because the moulding of the drive buffers is absent and the carcass is formed independently by clamping between two planar surfaces of the press mould. The drive buffers are vulcanized to the carcass in a subsequent stage after the entire carcass has been vulcanized. In this method of manufacturing rubber chains, there is no displacement of the metal ropes under the drive buffers and no disturbance in the stability of the buffers.

Description

[0001] Method for the production of rubber chains with positive drive for agricultural machinery

[0002] Field of invention

[0003] The present invention relates to a method of manufacturing rubber chains with positive drive for agricultural machinery, which will find application in the field of transport machinery and agriculture.

[0004] Prior art

[0005] Rubber chains for construction and agricultural machinery are made from a compound of natural and synthetic rubber, with added anti-abrasive chemical agents to reduce the percentage of wear caused by friction on abrasive or compact surfaces.

[0006] A method for producing rubber chains is known in the art, which includes the following operations:

[0007] - manufacture of raw non-vulcanized carcass;

[0008] - press fitting of moulded non- vulcanised rubber to form drive buffers; - positioning of the raw unvulcanised carcass on the bottom of the press mould;

[0009] - laying on the outer part of the carcass of raw non-vulcanised tread ribs; - simultaneous sector vulcanization of the carcass, the tread ribs on the outside and the drive buffers on the inside;

[0010] - repeat the above operation until the entire carcass, all drive buffers and chain tread ribs are vulcanized;

[0011] - removal of all flashes;

[0012] - inspection for defects and irregularities before commissioning.

[0013] A second method is known in the art, which includes the following operations:

[0014] - manufacture of raw non-vulcanized carcass;- press fitting of extruded raw rubber profiles, as well as the raw carcass; - sectoral vulcanization of both the carcass and the attached drive buffers; - positioning of the chain on the scraping machine to scrape its outer side; - placing strips of non- vulcanized calendered rubber on the scraped portion across the width of the chain;

[0015] - placing on the outer part of the layer of non-vulcanized rubber of tread ribs;

[0016] -vulcanization in autoclave of the chain with all tread ribs and the chain carcass;

[0017] - removing the circuit from the autoclave and inspecting it for defects and irregularities before commissioning.

[0018] In both methods press moulding is performed on a non-vulcanized carcass, where the pressure is not uniform due to the different relief of the surfaces resulting in the displacement of the metal threads in the carcass. When pressing between one planar and one profiled surface that forms the drive buffers in the inner part of the chain, the pressed buffers displace the metal ropes of the carcass in the transverse direction within 2-4 mm of each drive buffer. There is no deflection of the metal strands on either side of the pressed drive buffer of the chain as the pressing is between two planar surfaces. Therefore, below the drive buffers, the ropes and the protective layers of the carcass are displaced and take a sinusoidal shape along the length of the chain. On both sides of the drive buffers along the entire length of the chain, the ropes and protective layers remain unshifted. The width of the sinusoidal carcass layer is equal to the width of the drive buffer. This disrupts the stability of the drive buffer and shortens its useful life.

[0019] Attempts have been made to improve the stability of the drive buffers by placing a textile fabric (aramid) over them, which does not eliminate the absence of stability, but mitigates its effects. These attempts to increase the stability of the drive buffers have three drawbacks. The first is that the textile in question doesnot have the relative elongation of rubber and, in the process, cracks develop which grow over time and reduce the useful life of the rubber chain. The second disadvantage is that the aramid textile is a significant insulator and the temperature generated in the process of operating the rubber chain is retained in the drive buffer, and this is also an obstacle to long useful life. Thirdly, the bond between rubber and aramid has very low N / inm values which do not match the load on the drive buffers of the chain.

[0020] When the chain is operated and loaded, the metal strands that have a sinusoidal shape are stretched and this causes a change in the pitch of the drive buffers on the inside of the chain, making this pitch different from that intended when the chain was manufactured. As a result, during operation of the chain, the drive buffers are loaded unevenly relative to each other, some of them accepting a greater load than is permissible, causing them to fail and this shortens the life of the rubber chain.

[0021] There is no known method of manufacturing rubber chains in which the aforementioned deficiencies in the operation of the manufactured chains have been eliminated.

[0022] Technical background of the invention

[0023] It is the object of the invention to provide a method of manufacturing rubber chains with positive drive for agricultural machinery, which provides longer useful life, by manufacturing a tread and drive buffers on a pre-vulcanized carcass of the rubber chains.

[0024] The problem was solved by creating a method for the production of rubber chains with positive drive for agricultural machinery, including the following operations: manufacturing the carcass; removing the technological rubber flashes; performing visual inspection. According to the invention, the manufactured carcass is vulcanized by clamping between two molding die panels, wherein aftermanufacturing the vulcanized carcass and the operations of removing the process flashes and performing visual inspection, the following operations are performed:

[0025] roughening by scraping the outer side of the vulcanized carcass by means of a rotating cutting head of a scraping machine while the carcass is moving at a speed of 0 - 5 m / s;

[0026] reversing the vulcanized carcass by means of a device for reversing rubber chains so that the inner side becomes the outer side and the already scraped outer side becomes the inner side;

[0027] roughening of the inner side of the vulcanized carcass by means of a rotating cutting head of a scraping machine while the carcass is moving at a speed of 0 - 5 m / s;

[0028] reversing the rubber chain on a rubber chain turning machine to take its initial position;

[0029] application of an adhesive providing a bond between the vulcanized and roughened carcass and the applied non-vulcanized rubber, which adhesive connects the formed drive buffers on the inside of the carcass and the tread on its outside;

[0030] application of calendered non-vulcanized or extruded nonvulcanized rubber on the outside and inside of the already vulcanized carcass;

[0031] laying on the side of the carcass a layer of non-vulcanized rubber on the already vulcanized carcass;

[0032] moulding of lead or drive buffers, carried out on a moulding press in a cold press mould;

[0033] inserting the blanks of lead or drive buffers into the sockets on the bottom of the press mould;

[0034] mounting the prepared carcass of the rubber vulcanization chain on the bottom of the press mould;

[0035] positioning of extruded blocks of raw rubber on the outside of the already vulcanized carcass, forming the tread of the rubber chain after firing;stepwise pressing and firing of the rubber chain with a duration of 80 min to 180 min, pressure on the already vulcanized carcass from 20 kg / cm2to 45 kg / cm2and temperature from 130° C to 160° C by means of a sliding die which has the possibility of water cooling at both ends and this allows to ensure a continuous vulcanization process in the production of the entire chain.

[0036] An advantage of the developed method is the provided possibility of prolonging the useful life of rubber chains with positive drive for agricultural machinery by making a tread and drive buffers on a pre-vulcanized carcass. By increasing the stability of the drive buffers, the set pitch of the chain is maintained, and less heat is generated during chain operation, thus extending the chain life. Extending the life of rubber chains helps to protect the environment, reducing the amount of waste in nature and saving valuable raw materials for the production of new rubber chains.

[0037] Examples of embodiments of the invention

[0038] The developed method is used as follows.

[0039] A carcass is produced which is vulcanized by clamping it in a moulding die between two panels, keeping the distribution of the metal cords and protective layers uniformly in all planes.

[0040] The pre-vulcanized carcass is set by means of a gantry crane with two hoists on a scraping machine. The outer surface shall be removed by scraping in order to roughen the carcass and provide a surface to which the layers of non-vulcanized rubber to be laid subsequently will be more firmly bonded. The scraping shall be carried out by rotating the cutting head of the scraping machine and rotating the carcass at a speed of 0 - 5 m / s.

[0041] The carcass scraped on the outside is removed from the scraping machine by means of a gantry crane with two hoists and set on a rubber chain turning machine. On the rubber chain turning machine, the carcass is reversed by meansof rotating forks so that the inner untreated side becomes the outer side and the already scraped outer part becomes the inner side.

[0042] After turning the carcass by means of a gantry crane with two hoists, the carcass is settled again on a scraping machine. The outer layer of the carcass is removed by scraping in order to provide a surface to which the layers of nonvulcanized rubber to be laid on the already vulcanized carcass can be firmly bonded. The scraping shall be done by means of a rotating cutting head and movement of the carcass at a speed of 0 - 5 m / s.

[0043] The carcass, scraped on both sides, is moved by the gantry crane with two hoists from the scraping machine to the rubber chain turning machine, then the carcass is reversed again so that it takes its original shape with the surface to which the tread blocks will be pressed on the outside and the surface to which the drive buffers will be pressed on the inside.

[0044] The turned carcass with the gantry crane and two hoists is removed from the turning machine and set on the local repair facility where, after cleaning from dust and chips, an adhesive treatment is carried out on both treated surfaces. The adhesive is applied bilaterally to both the machined outer and inner parts and to the side part representing the thickness of the chain carcass.

[0045] After the applied adhesive dries, non- vulcanized rubber is applied or extruded on both sides of the carcass, which after pressing and firing restores the scraped upper layers of the carcass, both on the tread side and on the side where the drive buffers are attached.

[0046] The following is the operation for moulding the drive buffers. In the present method, a molding press consisting of two parts, upper and lower, is used to form both a protector on the upper - outer part of the chain and drive buffers on the lower inner part. A sliding die is used to form the protector and drive buffers.

[0047] This allows for even distribution of the tread blocks on the outside of chain and the drive buffers on the inside of the chain, regardless of the difference in length of the individual carcasses being used. For the moulding of the drivebuffers, the lower part of the press mould is used, into the sockets of which extruded blocks of warm non-vulcanized rubber are inserted. A flat base is placed on top of the blocks so arranged and then the press is closed under a cold forming press and pressed at 70 bar for 1 min. The press is opened, and the moulded buffers are removed. The required number of drive buffers to produce one chain is made. The already formed blanks of the drive buffers of the rubber chain are placed into the sockets of the bottom of the press mould.

[0048] With the gantry crane with two hoists, the rubber chain carcass is placed on the forming press. Using a special device on the press, the carcass is lowered onto the drive buffer blanks already placed at the bottom of the mould. Blocks of raw extruded rubber are positioned on the top of the carcass by means of a template and, after firing, form the tread of the rubber chain. After positioning the moulded drive buffers in the sockets on the bottom of the mould and the blocks of non¬ vulcanized rubber on the carcass, the mould is closed.

[0049] The mould is designed and made with a water jacket so that cooling can be carried out at both ends. After closing the press, a firing of a sector of the chain covered by the press mould is carried out with a duration of 80 min to 180 min, a pressure on the already vulcanized carcass of 20 kg / cm2to 45 kg / cm2and a temperature of 130° C to 160° C . For the production of the entire rubber chain, firing is carried out in n number of sections, and depending on the length of the chain, the corresponding number of molded blanks of drive buffers are placed in the sockets of the lower part of the press mold, and the corresponding number of extruded blocks on the upper part of the carcass required to form the new tread of the rubber chain.

[0050] When the first segment of the circuit is fired, the press mould is cooled on both sides, thus leaving one non-vulcanized drive buffer at the bottom of the press mould and two extruded blocks forming the new protector at the top.After firing the first sector, the cooling of the press mould on the side of the already fired sector is stopped and the cooling is left working only on the side of the next sectors to be fired.

[0051] When the second sector is fired, the chain is moved so that a fully vulcanized drive buffer and the following non-vulcanized buffer from the firing of the previous sector fall into the bottom of the press mold. Correspondingly, two fully vulcanized blocks from the tread and the next two non-vulcanized blocks from the previous firing fall into the upper portion of the press mould. This ensures continuous and uniform vulcanization along the entire length of the produced positive drive chain.

[0052] When the last n- sector is fired, the cooling of the press mould is stopped completely in order to fully vulcanize the part of the first sector that remains nonvulcanized and the remaining non-vulcanized buffer and blocks from the last sector.

[0053] Depending on the length of the rubber chain, different numbers of vulcanized buffers in the lower part and the corresponding number of vulcanized tread blocks in the upper part may fall into the press mould when firing the last sector.

[0054] After the entire chain is fired, it is removed from the press and mounted on the vertical stand using the gantry crane with two hoists to remove the process rubber flashes.

[0055] A visual inspection of the rubber chain shall be made for any irregularities and if none are found the chain shall be allowed to operate.

[0056] In this method of manufacturing rubber chains, there is no displacement of the metal ropes under the drive buffers, and there is no disturbance in the buffer's stability. In addition, when pressing between two planar surfaces, the pressure can be increased up to 50 kg / cm2, resulting in a much better bond between the metal cords of the carcass and the rubber, which increases the strength of the carcass significantly.

Claims

PATENT CLAIMSl.A method of manufacturing rubber chains with positive drive for agricultural machinery, comprising the steps of: manufacturing a carcass; removing process flashes from the rubber; and performing visual inspection, characterized in that the manufactured carcass is vulcanized by pressing between two moulding die plates, wherein after manufacturing the vulcanized carcass and the operations of removing process flashes and performing visual inspection, the following operations are performed:roughening by scraping the outer side of the vulcanized carcass by means of a rotating cutting head of a scraping machine while the carcass is moving at a speed of 0 - 5 m / s;reversing the vulcanized carcass by means of a device for reversing rubber chains so that the inner side becomes the outer side and the already scraped outer side becomes the inner side;roughening of the inner side of the vulcanized carcass by means of a rotating cutting head of a scraping machine with the carcass moving at a speed of 0 - 5 m / s;reversing the rubber chain on a rubber chain turning machine to take its original position;application of an adhesive providing a bond between the vulcanized and roughened carcass and the applied non-vulcanized rubber, which adhesive bonds the formed drive buffers on the inside of the carcass and the tread on its outside;laying of calendered non-vulcanized or extruded non-vulcanized rubber on the outside and inside of the already vulcanized carcass;laying or extrusion on the side of the carcass of a layer of nonvulcanized rubber on an already vulcanized carcass;moulding of lead or drive buffers, carried out on a moulding press in a cold press mould;inserting the blanks of lead or drive buffers into the sockets on the bottom of the press mould;mounting the prepared rubber carcass for vulcanization on the bottom of the press mould;positioning of extruded blocks of raw rubber on the outside of the already vulcanized carcass, forming after firing the tread of the rubber chain;stepwise pressing and firing of the rubber chain in a duration of 80 min to 180 min, pressure on the already vulcanized carcass from 20 kg / cm2to 45 kg / cm2and temperature from 130° C to 160° C through a sliding die which has the possibility of water cooling at both ends, ensuring a continuous vulcanization process in the production of the entire chain.