Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D25/00—Working sheet metal of limited length by stretching, e.g. for straightening
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D3/00—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts
  • B21D3/12—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts by stretching with or without twisting
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
  • F04C14/08—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the rotational speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2/00—Rotary-piston machines or pumps
  • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
  • F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
  • F04C2/101—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member with a crescent-shaped filler element, located between the inner and outer intermeshing members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2/00—Rotary-piston machines or pumps
  • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
  • F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
  • F04C2/102—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member the two members rotating simultaneously around their respective axes

Definitions

• the present invention refers to a stretching machine for non-ferrous metal profiles.
• Stretching machines for non-ferrous profiles are machines designed to permanently extend an extruded profile by applying a force parallel to the main axis, so as to give it a desired permanent straightness.
• the process for producing non-ferrous profiles includes heating a billet which is then pressed by means of a die which gives it the desired shape.
• the profile obtained is then cooled.
• the profile may encounter a series of morphological modifications due to the different cooling speed of its various parts.
• the stretching of the extruded profile has the object of eliminating warpage, curvature and undulation of the profile which may be determined by the different cooling speed of its various parts.
• the stretching machine for non-ferrous profiles usually comprises two functional units: a head and a tail, provided with clamps for attaching each end of the profile to be stretched.
• the former normally covers the function of extending the profile to be stretched, even though it is not excluded that both the head and tail can carry out the stretching function.
• the head of the stretching machine is driven by a hydraulic power unit, the pump of which drives the main stretching cylinder.
• the types of pumps used are vane or piston pumps and the flow rate change is obtained by means of a proportional valve which, when programmed, allows to obtain acceleration and deceleration ramps at the beginning and at the end of the stretching.
• a proportional valve which, when programmed, allows to obtain acceleration and deceleration ramps at the beginning and at the end of the stretching.
• further moving parts with small size cylinders clamp, vanes, strips, etc
• a further auxiliary pump is usually required.
• US 6018970 A describes a stretching machine for metal sheets comprising two jaws adapted to be placed at the ends of the sheet to be stretched. Each jaw comprises friction elements to lock the metal sheet.
• FR 2216033 Al describes a machine for measuring the extension of the profile bars. Said machine comprises two heads adapted to mechanically lock the profile and adapted to slide in opposite directions.
• DE 10005779A1 describes work equipment, such as for example a lift truck, comprising hydraulic drives.
• the hydraulic circuits of said work equipment include the employment of gear pumps.
• the pumps used on classic stretching machines are piston pumps, such pumps have a noise above 85 dB, imposing the employer to seclude the pumps in specific production sectors and to provide the employees with individual and collective protection devices.
• the permanent rotation of the pump generates an inceimpuls noise around the region of the hydraulic power unit, which noise is higher than the values established by the Italian law and requires precise counter-measures be adopted for the hearing protection of the personnel working or transiting in such area.
• a further disadvantage is given by the continuous rotation of the stretching pump which generates an energy expenditure.
• the constant rotation of the pump between two consecutive working cycles provokes the overheating of the hydraulic fluid which must be cooled by means of a heat exchanger.
• the secondary movement of the accessories requires a motor and at least one auxiliary pump, thereby increasing the total energy demand of the stretching machine.
• Figure 1 shows an operating diagram of a stretching machine for non- ferrous profiles according to the present invention
• Figure 2 shows a side sectional view of a head of the stretching machine
• Figure 3 shows a side sectional view of an internal gear pump
• Figure 4 shows a front view of the internal gear pump
• Figure 1 shows a head 2 of a stretching machine 1 for non-ferrous profiles comprising a body 22, a clamp 21 , hydraulic cylinders 3 and 31 , an internal gear pump 4, an electric motor 5, a liquid tank 6, an electro- distributor 7 and a hydraulic circuit 8.
• the hydraulic circuit uses a single pump model 4 on stretching machine 1 , or all movements of stretching machine 1 and all the main functions thereof are carried out exclusively by internal gear pump 4.
• Cylinder 3 receives the hydraulic fluid from internal gear pump 4 by means of hydraulic circuit 8 and is adapted to control the horizontal movements of at least one of the heads 2 of stretching machine 1.
• Clamp 21 of head 2 is adapted to be driven under the effect of a hydraulic fluid maintained under pressure within hydraulic circuit 8 by internal gear pumps 4 controlled in turn by electric motor 5. Once the internal gear pump 4 has been actuated, the hydraulic fluid sets the second cylinder 31 under pressure setting in turn clamp 21 in motion ( Figure 1 ).
• the inflow of the hydraulic fluid in the second cylinder 31 is adapted to cause the lifting of clamp 21 while the reduction of the pressure of the hydraulic fluid causes the lowering of clamp 21 against base 221 of body 22 of head 2. Due to the seal of hydraulic circuit 8, the pressure of the hydraulic fluid maintains clamp 21 lowered towards base 221 of body 22, generating a friction between clamp 21 and the base 221 of the body 22.
• Clamp 21 driven by the second cylinder 31, is adapted to lock a metal profile between the same clamp 21 and the base 221 of the body 22 of said head 2.
• internal gear pumps 4 not only control the horizontal movement of head 2 by means of cylinder 3, but also the drive of the clamp 21 of head 2 by means of the second cylinder 31.
• the internal gear pump 4 is controlled in turn by motor 5 which regulates the rotary movement thereof thus determining the RPM (revolutions per minute) to be maintained. Therefore, the internal gear pump 4 has a fixed displacement/flovv rate, the flow rate change is achieved due to the change in the rotation speed of motor 5.
• Motor 5 is a conventional four-pole, three-phase asynchronous motor, comprising a forced ventilation system. Electric motor 5 is designed to be connected to a frequency variator, so as to ensure a much higher performance than the conventional asynchronous electric motors.
• Internal gear pump 4 is normally stopped in a situation of non-use of stretching machine 1 and is silent. At the precise moment when a movement of stretching machine 1 is required, the internal gear pump 4 is automatically set in motion reaching the number of revolutions needed to ensure proper oil flow required for the required operation. The oil is forced into hydraulic circuit 8 by means of electro-distributor 7. When the movement is completed, motor 5 immediately reduces the rotation until it turns off, The maximum noise of the internal gear pump 4 measured at maximum speed is lower than 80 dB. The type of internal gear pump 4 used allows the exclusion of any auxiliary pump.
• the internal gear pump 4 is directly connected to motor 5 by means of a flexible coupling.
• the internal gear pump 4 ( Figures 3 and 4) comprises a fastening flange 451, a hydrodynamic support pinion shaft 454, a housing 452, a cover 453 with a through shaft, a hollow wheel 451 1, plain bearings 456, axial plates 457, a stop pin 459 and a radial compensation segment 4514.
• the pinion shaft 454 is adapted to be coupled to the hollow toothed wheel 4511 by means of the teeth 4519 which radially protrude outside said pinion shaft 454. Said teeth 4519 are adapted to mesh with teeth 4518 protruding towards the interior of the hollow toothed wheel 451 1 , thus causing the latter to rotate. During the rotation, the radial forces exerted on the toothed wheel 451 1 under pressure are largely absorbed by the hydrostatic bearing 450. Moreover, the pinion shaft 454 is supported by a radial slide bearing 4515 hydrodynamically lubricated.
• the space between the teeth 4513 of the hollow toothed wheel 4511 of the internal gear pump 4 is adapted to draw the fluids, for example oil.
• the liquid enters into the cavities formed between the teeth 4513: when the space between the teeth 4513 is reduced, the volume is reduced and the liquid is forced outside through an outlet channel 4517.
• Internal gear pump 4 is mounted directly inside the liquid tank so as to reduce the sound more.
• Using internal gear pumps advantageously allows to achieve the yield standards of the piston pumps but with lower costs in terms of cost of the pump itself, consumption of the gear pumps, and maintenance of the gear pumps.
• a further advantage is given by the fact that the pump remains turned off between a working cycle and the next one, generating an appreciable energy saving.
• the lower use of the hydraulic fluid due to the targeted powering of the pump exclusively limited to the precise number of revolutions (oil flow rate) required by the work, minimizes the electrical consumption of the motor and the overheating of the hydraulic fluid which will require, in this case, a heat exchanger of a smaller size and therefore with lower energy consumption.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Details And Applications Of Rotary Liquid Pumps (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 2016
  • 2016-06-09 EP EP16791432.4A patent/EP3307451A2/de not_active Withdrawn
  • 2016-06-09 WO PCT/IB2016/053402 patent/WO2016199061A2/en active Application Filing

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