DESC:FIELD OF THE INVENTION
[001] The present invention relates to a lubrication system for an extrusion press. More particularly, the present invention relates to lubrication of a dummy block in an extrusion press.

BACKGROUND OF THE INVENTION
[002] Generally, an extrusion press is widely utilised for forming extruded metal products. During extrusion, a preheated metal alloy billet such as aluminium is forced through a die with a specific cross-sectional profile, and a pressing ram pushes the aluminium billet through the die to get a required cross-sectional profile.
[003] A dummy block generally made of steel is connected to the main ram, and the dummy block is configured to be in contact with the billet and transmit the force of the main ram to the billet during the extrusion process. The dummy block thus prevents contact of the billet with the main ram. However, during extrusion process the alloy (to be formed) is heated at high temperature (app 450°C), and at such high temperature, the alloy tends to stick to dummy block. When the hot billet is forcefully removed from the dummy block, it leads to potential damage to the dummy block or billet, or causes blisters in the billet profile. When the parts of the billet are stuck to the dummy block, the dummy block gets damaged beyond repair and must be changed, which is a cumbersome process. Hence it must be ensured that the billet and the dummy block must separate instantly without damage to the dummy block or the billet.
[004] In order to make the separation of the dummy block from the billet easier, lubricants are applied to the face of the dummy block which comes in contact with the billet or the face of the billet which comes in contact with the dummy block. Liquid lubricants such as water-based liquid lubricants are preferred over other conventional lubricants such as graphite grease, acetylene flame, boron nitride powder since these conventional lubricants have several disadvantages such as health and safety hazard, product quality, operator friendliness and environmental considerations. Moreover, since water-based liquid lubricants, such as Boron Nitride are well suited for high pressure and high temperature applications, and hence are preferred for extrusion process.
[005] The lubrication of dummy block is generally preferred over lubrication of the billet because when the liquid lubricant is applied on the end face of the billet, the lubricant tends to dry up quickly due to the heat of the billet. Further, when the lubricant is sprayed on the billet, the lubricant may cover only the surface of the billet, and if the diameter of the billet is smaller than the diameter of the dummy block, there is a chance for the billet to stick to the topmost surface of the dummy block.
[006] In conventional systems, the lubricant is applied to the dummy block by means of pneumatic cylinders. The lubrication is applied only when the main ram reaches its rearmost position. For effective lubrication, the main ram must stop for a predetermined period of time in each cycle while the lubrication is applied to the dummy block. This results in increasing the total extrusion cycle time per billet, which leads to high production losses. Further, in such conventional systems, a large number of sensors, valves and actuators are required for sensing and facilitating movement of lubricating elements such as nozzle for timely lubrication of the dummy block. This not only leads to the lubrication system being extremely complex, but also increases the risk of damage to components in case of any malfunction.
[007] Hence there is a need in the art for a lubrication system for an extrusion press which solves at least the aforementioned problems.

SUMMARY OF THE INVENTION
[008] In one aspect, the present invention is directed towards a lubrication system for an extrusion press. The lubrication system has a guide assembly fixedly attached to a main ram. In that, the main ram is configured to move in a front-rear direction on a base frame. Further, the main ram has a main stem and a dummy block attached to the main stem. The lubrication system further has an arm member pivotally mounted on the extrusion press at a first end of the arm member and extending towards a second end. The arm member is supported on the guide assembly and translational movement of the guide assembly causes the pivotal movement of the arm member about the first end. The lubrication system further has a nozzle provided on the second end of the arm member. The nozzle is configured to release lubricant towards the dummy block.
[009] In an embodiment of the invention, the arm member is pivotally movable between a first position and a second position. In that, the arm member is in the first position when the main ram is at a forwardmost position, and the arm member is in the second position when the main ram is at a rearmost position.
[010] In a further embodiment of the invention, the lubrication system has a lubrication tube supported on the arm member. The nozzle is configured to receive lubricant from the lubrication tube and release lubricant towards the dummy block when the arm member is in the second position.
[011] In a further embodiment of the invention, the guide assembly has a mounting bracket fixedly attached to the main ram. A guide wheel is rotatably provided on the mounting bracket and the arm member is supported on the guide wheel.
[012] In a further embodiment of the invention, the lubrication system has a swivel bracket. The swivel bracket is provided between the guide wheel and the mounting bracket for allowing the guide wheel to swivel for being constantly aligned with the arm member.
[013] In a further embodiment of the invention, the arm member is pivotally mounted on a hydraulic oil reservoir of the extrusion press.
[014] In a further embodiment of the invention, the lubrication system has a lubricant reservoir for supplying lubricant to the lubrication tube, and a valve manifold for controlling the flow of lubricant from the lubricant reservoir to the lubrication tube.
[015] In a further embodiment of the invention, the lubrication system has a sensor for sensing the position of the main ram, and a control unit for actuating the valve manifold for allowing flow of lubricant in the lubrication tube.
[016] In a further embodiment of the invention, the lubrication system has a pointer joint and a pointer tube for connecting the nozzle to the second end of the arm member.

BRIEF DESCRIPTION OF THE DRAWINGS

[017] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a schematic diagram of an extrusion press incorporating a lubrication system, in accordance with an embodiment of the invention.
Figure 2 illustrates another schematic diagram of an extrusion press incorporating the lubrication system, in accordance with an embodiment of the invention.
Figure 3 illustrates a side view of the lubrication system, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[018] The present invention is directed towards lubrication of a dummy block of an extrusion press during an extrusion cycle, whereby the dummy block is lubricated without interrupting the extrusion cycle. The present invention is designed to work without any manual intervention, and thus obviates any downtime of the extrusion press for lubricating the dummy block.
[019] Figure 1 illustrates a lubrication system 300 for an extrusion press 100 in accordance with an embodiment of the invention. In an embodiment, the lubrication system 300 for the extrusion press 100 of the present invention is capable of being adapted to extrusion presses for extrusion of metals, metal alloys and nonmetals. Depending upon material being extruded, the lubricant is chosen so as to ensure that there are no defects formed in the material during the extrusion process. In this regard, the lubricant is preferably a liquid lubricant such as water-based liquid lubricants.
[020] Figure 1 and Figure 2 illustrates the extrusion press 100 incorporating the lubrication system 300 in accordance with an embodiment of the invention. As illustrated in Figure 1 and Figure 2, the extrusion press 100 comprises of a main ram 122. The main ram 122 is supported on a base frame 140 of the extrusion press 100. The extrusion press 100 further comprises a main stem 114. The main stem 114 is fixedly attached to the main ram 122 and extends forwardly from the main ram 122. The extrusion press 100 further comprises a dummy block 112 that is attached to the main stem 114. In an embodiment, the dummy block 112 is preferably made of steel. During an extrusion cycle, the main ram 122 is configured to move in a front-rear direction along the base frame 140. In an embodiment, the main ram 122 moves between a forwardmost position and a rearmost position. When the main ram 122 moves forward to the forwardmost position, the dummy block 112 is configured to come in contact with a billet (not shown) provided in a billet container 128. As the dummy block 112 transmits the force of the main ram 122 to the billet, the billet moves through a die provided in the billet container 128, and the extruded job is output on the other side of the container though a front platen 134. The extruded product shall have a cross-sectional shape which generally conforms to the shape of the die. Further, the system comprises a hydraulic oil reservoir 138, wherein hydraulic oil reservoir 138 stores the oil for hydraulic control of the main ram 122 and other components of the extrusion press 100 through a main hydraulic cylinder 124, a side cylinder 126 and a rear platen 132.
[021] Further, as illustrated in Figure 1 and Figure 2, the extrusion press 100 incorporating the lubrication system 300 has a guide assembly 310 and an arm member 320. The guide assembly 310 is fixedly attached to the main ram 122, and thus when the main ram 122 moves in the front-rear direction, the guide assembly 310 moves along with the main ram 122. In an embodiment, as illustrated, the guide assembly 310 comprises a mounting bracket 316 (shown in Figure 3) that is fixedly attached to the main ram 122 and extends upwardly from the main ram 122. The guide assembly 310 further comprises a guide wheel 312 that is rotatably provided on the mounting bracket 316. The guide wheel 312 is free to rotate along a support point on the mounting bracket 316.
[022] The arm member 320 extends from a first end 320A to a second end 320B, and the arm member 320 is pivotally mounted on the extrusion press 100 at the first end 320A of the arm member 320. In an embodiment, the arm member 320 as shown is pivotally mounted on the hydraulic oil reservoir 138 of the extrusion press 100. In an embodiment, as shown in Figure 3, the arm member 320 is pivotally mounted at the first end 320A to the extrusion press 100 by means of a pivot bracket 318.
[023] As illustrated in Figure 1 and Figure 2, the arm member 320 is configured to be supported on the guide assembly 310, wherein translational movement of the main ram 122, and the guide assembly 310 causes pivotal movement of the arm member 320 about the first end 320A. In an embodiment, translational movement of the guide assembly 310 causes the pivotal movement of the arm member 320 between a first position and a second position depending upon position of the main ram 122.
[024] In an embodiment, the guide wheel 312 comprises a groove along its circumference/periphery, and the arm member 320 is configured to be supported on the groove of the guide wheel 312. Thus, in operation, if the main ram 122 moves forward, the guide wheel 312 moves along the arm member 320, and the arm member 320 moves pivotally between the first position and the second position.
[025] As illustrated in Figure 1, the arm member 320 is in the first position when the main ram 122 is at the forwardmost position, and as illustrated in Figure 2 the arm member 320 is in the second position when the main ram 122 is at the rearmost position. As discussed hereinbefore, when the main ram 122 moves forward, the guide wheel 312 moves along the arm member 320 towards the second end 320B of the arm member 320 causing the arm member 320 to move pivotally upwards to the first position i.e., away from the dummy block 112. Similarly, when the main ram 122 moves backward, the guide wheel 312 moves along the arm member 320 towards the first end 320A of the arm member 320 allowing the arm member 320 to move pivotally to the second position i.e., towards the dummy block 112. Thus, when the main ram 122 is at the forwardmost position, the arm member 320 moves away from the dummy block 112, and as the main ram 122 moves backward after an extrusion cycle for the next cycle, the arm member 320 moves towards the dummy block 112 till the arm member 320 reaches the second position.
[026] Further, the rotation of the guide wheel 312 as it moves along the arm member 320 minimises friction between the guide assembly 310 and the arm member 320 facilitating smooth movement of the arm member 320. For ensuring that the guide wheel 312 is capable of aligning itself with the arm member 320 in all positions of the arm member 320, as illustrated in Figure 3, in an embodiment, the lubrication system 300 has a swivel bracket 314 positioned below the guide wheel 312, and more particularly provided between the guide wheel 312 and the mounting bracket 316. The swivel bracket 314 allows the guide wheel 312 to swivel for being constantly aligned with the arm member 320.
[027] For lubricating the dummy block 112, the lubrication system 300 has a nozzle 328 provided on the second end 320B of the arm member 320, and the nozzle 328 is configured to release lubricant towards the dummy block 112. The nozzle 328 is configured release or spray the lubricant towards the dummy block 112, and more particularly towards a face of the dummy block 112.
[028] As illustrated in Figure 3, in an embodiment, the lubrication system 300 further has a lubrication tube 340. The lubrication tube 340 is supported on the arm member 320. Accordingly, the lubrication tube 340 moves with the arm member 320. In an embodiment, the lubrication tube 340 is configured to receive lubricant from a lubricant reservoir 352. The lubricant reservoir 352 is connected to a pumping station 344 through a suction tube 350. The pumping station 344 comprises a pumping cylinder 348 and a valve manifold 346, wherein the valve manifold 346 controls the flow of the lubricant towards the lubrication tube 340. The valve manifold 346 comprises of one or more solenoid valves (not shown) which are electronically controlled or actuated. The pumping station 344 is connected to the lubrication tube 340 by means of an auxiliary lubrication tubing 342. In an embodiment, the lubrication tube 340 is fluidly connected to the auxiliary lubrication tubing 342 means of an inlet connector 330. In an embodiment, the lubrication tube 340 and the auxiliary lubrication tubing 342 are integrated into a single lubrication tube.
[029] Further, to release the lubricant towards the dummy block 112, the nozzle 328 is provided on the second end 320B of the arm member 320. The nozzle 328 is configured to receive the lubricant from the lubrication tube 30 through a flexible hose 324 and release or spray the lubricant towards a dummy block 112, and more particularly towards a face of the dummy block 112 when the arm member 320 is in the second position. In an embodiment, the flexible hose 324 is made of polyurethane. Polyurethane is suitable for conveying moderate pressure liquids in industrial environments owing to ease of 11 connection of polyurethanes hoses, which enhances ease of assembly and serviceability. Further, polyurethane is capable of withstanding high ambient temperatures and can withstand high pressures, making the flexible hose 324 durable since the flexible hose 324 is subjected to high temperatures as well as high pressures. In an alternative embodiment, the flexible hose 324 is made of nylon or neoprene rubber tubing. In an embodiment the flexible hose 324 serves as a flexible conduit for conveying lubricant between the pointer tube 326. In an embodiment, the nozzle 328 is a spray nozzle that is configured to spray atomised lubricant on the face of the dummy block 112, thus ensuring even distribution of lubrication along the face of the dummy block 112.
[030] In an embodiment, the nozzle 328 is connected to the second end 320B of the arm member 320 through a pointer joint 322 and a pointer tube 326. The provision of the pointer joint 322 and the pointer tube 326 allows for the orientation of the nozzle 328 to be changed as per the shape, size and configuration of the dummy block 112. In an embodiment, the inclination of the nozzle 328 is provided such that when the arm member 320 is in the second position, or when the main ram 122 is at the rearmost position, the nozzle 328 faces towards a lower portion of the face of the dummy block 112. As the main ram 122 moves forward and the arm member 320 moves up from the second position, the nozzle 328 moves towards the upper portion of the face of the dummy block 112, thereby ensuring adequate lubrication of the face of the dummy block 112. In an embodiment, the nozzle 328 has a spray cone angle of 20 degrees for ensuring a sufficiently wide spraying range for the lubricant.
[031] In an embodiment, the nozzle 328 sprays the lubricant towards the dummy block 112 only when the nozzle 328 is facing the dummy block 112, that is starting from when the arm member 320 is in the second position, for a predetermined period of time. To facilitate that, the lubrication system 300 comprises a sensor (not shown) for sensing the position of the main ram 122. In operation, after an extrusion process, for the next cycle, when the main ram 122 reaches the rearmost position, the same is detected by the sensor and communicated to a control unit (not shown). Since when the main ram 122 is in the rearmost position, the arm member 320 is in the second position with the nozzle 328 facing the dummy block 112, the control unit actuates the valve manifold 346 to allow flow of lubricant in the lubrication tube 340 towards the nozzle 328, and the lubricant is then sprayed on to the dummy block 112. Thus, once the main ram 122 reaches the rearmost position, there is no time lag in the nozzle 328 being aligned with the face of the dummy block 112, thereby eliminating any requirement. As soon as the main ram 122 reaches the rearmost position, the main ram 122 is configured to immediately begin movement towards the forwardmost position. As the main ram 122 moves forward, the arm member 320 moves upwards and the nozzle 328 moves towards the upper portion of the face of the dummy block 112, thus lubricating the upper portion of the face of the dummy block 112. After the predetermined time, as the nozzle 328 moves further up and away from the face of the dummy block 112, the control unit actuates the valve manifold 346 to stop of the flow of the lubricant, thereby ensuring that the lubricant is sprayed only when the cone of spray from the nozzle 328 is towards the dummy block 112, thereby preventing any lubricant wastage. The process is repeated for every cycle which ensures that the dummy block 112 is sufficiently lubricated in every cycle.
[032] Advantageously, the present invention provides an extrusion press incorporating the lubrication system which eliminates the requirement of the main ram having to stop for a certain period of time for lubrication. The present invention ensures that the dummy block is adequately lubricated while the main ram is constantly moving since the arm member aligns itself with the movement of the main ram. The elimination of the requirement of the main ram to stop provides for reduction in extrusion time per billet and thus reduction in production costs.
[033] Adequate lubrication to the dummy block ensures that the dummy block and the billet can be separated easily at the end of an extrusion cycle, thus preventing damage to the dummy block and the billet. This further ensures that the frequency of replacement of dummy block is lower than conventional systems, which not only results in cost saving, but also reduces the cumbersome requirement of dummy block replacement.
[034] Furthermore, the present invention achieves an automated lubrication of the dummy block without requiring any additional sensors, valves and actuators. This makes the lubrication system simpler, easier to assemble and maintain, and has lower associated costs. In addition, the reduced part count also improves the reliability of the lubrication system.
[035] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.
,CLAIMS:WE CLAIM:
1. A lubrication system (300) for an extrusion press (100), the lubrication system (300) comprising:
a guide assembly (310) fixedly attached to a main ram (122), the main ram (122) being configured to move in a front-rear direction on a base frame (140), the main ram (122) comprising a main stem (114) and a dummy block (112) attached to the main stem (114);
an arm member (320) pivotally mounted on the extrusion press (100) at a first end (320A) of the arm member (320) and extending towards a second end (320B), the arm member (320) being supported on the guide assembly (310), and translational movement of the guide assembly (310) causes the pivotal movement of the arm member (320) about the first end (320A); and
a nozzle (328) provided on the second end of the arm member (320), the nozzle (328) being configured to release lubricant towards the dummy block (112).

2. The lubrication system (300) as claimed in claim 1, wherein the arm member (320) is pivotally movable between a first position and a second position, wherein the arm member (320) is in the first position when the main ram (122) is at a forwardmost position and the arm member (320) is in the second position when the main ram (122) is at a rearmost position.

3. The lubrication system (300) as claimed in claim 2, comprising a lubrication tube (340) supported on the arm member (320), wherein the nozzle (328) is configured to receive lubricant from the lubrication tube (340) and release lubricant towards the dummy block (112) when the arm member (320) is in the second position.

4. The lubrication system (300) as claimed in claim 1, wherein the guide assembly (310) comprises a mounting bracket (316) fixedly attached to the main ram (122), and a guide wheel (312) rotatably provided on the mounting bracket (316), wherein the arm member (320) is supported on the guide wheel (312).

5. The lubrication system (300) as claimed in claim 4, comprising a swivel bracket (314), the swivel bracket (314) being provided between the guide wheel (312) and the mounting bracket (316), for allowing the guide wheel (312) to swivel for being constantly aligned with the arm member (320).

6. The lubrication system (300) as claimed in claim 1, wherein the arm member (320) is pivotally mounted on a hydraulic oil reservoir (138) of the extrusion press (100).

7. The lubrication system (300) as claimed in claim 3, comprising a lubricant reservoir (352) for supplying lubricant to the lubrication tube (340), and a valve manifold (346) for controlling the flow of lubricant from the lubricant reservoir (352) to the lubrication tube (340).

8. The lubrication system (300) as claimed in claim 7, comprising a sensor for sensing the position of the main ram (122), and a control unit for actuating the valve manifold (346) for allowing flow of lubricant in the lubrication tube (340).

9. The lubrication system (300) as claimed in claim 1, comprising a pointer joint (322) and a pointer tube (326) for connecting the nozzle (328) to the second end (320B) of the arm member (320).

Dated this 29th day of September 2023

Hindalco Industries Limited
By their Agent & Attorney

(Nisha Austine)
of Khaitan & Co
Reg No IN/PA-1390