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
  • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
  • B21D5/04—Bending sheet metal along straight lines, e.g. to form simple curves on brakes making use of clamping means on one side of the work
  • B21D5/045—With a wiping movement of the bending blade
• • 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
  • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
  • B21D5/04—Bending sheet metal along straight lines, e.g. to form simple curves on brakes making use of clamping means on one side of the work

Definitions

• the present invention relates to a device for moving part of a machine and exerting a force at the end of the stroke.
• Such a device can be used in a machine tool, such as for example a punching machine or a folder.
• a machine tool such as for example a punching machine or a folder.
• the tool the punch or the folding head
• the tool is first approached the workpiece and then, at the end of the stroke, a significant force is exerted on the tool.
• the fluid used to supply the cylinders has physical properties (viscosity, etc.) dependent on the temperature. A variation of this leads to changes in the pressure delivered by the unit supplying the hydraulic circuit with hydraulic fluid. As the pressure varies, the force exerted by the jack on a displaced object also varies. To obtain a constant effort, whatever the ambient temperature, summer and winter, a pressure regulation system is necessary.
• the system may include a refrigeration device and a heater to maintain the hydraulic fluid at a constant temperature.
• a hydraulic circuit also requires regular maintenance.
• the fluid used can bring in impurities and a filtration system is necessary.
• the filters must be cleaned and the hydraulic fluid must be drained.
• the use of servo valves, necessary in a circuit with regulation efficient, requires always a clean hydraulic fluid.
• the object of the invention is to provide a device for moving part of a machine by exerting a significant end-of-travel effect and making it possible to use a source of clean energy which does not pose major servo-control problems. .
• the device which it offers is a device for moving a part of a machine and exerting an end-of-travel force comprising: - a first assembly intended to move the part of the machine,
• the first assembly is a rotationally driven assembly mounted on at least a first bearing
• the second rotationally driven assembly is mounted on at least a second bearing
• the axis defined by the first bearings is offset from to the first, respectively second, connecting axis.
• the device has a first system for moving the part of the machine mounted in series with an eccentric system.
• the first system allows the movement of the part of the machine to be moved without exerting any particular effort on this part and the second allows to exert a force on this part of machine.
• the first system is chosen according to the desired travel stroke.
• the offset between the bearing axis and the second connecting axis is chosen according to the effort to be exerted. When the effort to be exerted is significant, the offset is small. In this way, an electric motor provides sufficient torque to obtain the desired force at the part of the machine.
• This configuration allows the use of electric motors. These do not pollute, require little maintenance and their servo systems are inexpensive.
• the first assembly comprises a shaft driven in rotation at the end of which is mounted a plate having an offset crank pin serving as the first connecting axis for the connecting element
• the second assembly is constituted by a crankshaft having two bearings of connecting rods defining the connecting axis of the connecting piece and a crankshaft bearing on which the part of the machine to be moved is mounted.
• the first, respectively the second, together are constituted by a crankshaft having two bearings constituting the first, respectively the second, bearings and a bearing, placed between these two bearings whose axis corresponds to the connecting axis of the connecting piece, the first bearings are mounted in a fixed frame of the machine, and the second bearings are integral with the part of the machine to be moved.
• the sets driven in rotation can be directly or indirectly.
• the first assembly and / or the second assembly is mounted on the output shaft of an electric motor.
• the first set and / or the second set is rotated by a pulley over which passes a belt, preferably a toothed belt.
• the first and second sets are each provided with a pulley, the two pulleys being parallel to a third pulley driven by a motor and a single toothed belt transmitting the rotational movement of the third pulley to the first two.
• This embodiment makes it possible to use only one motor and also to perfectly synchronize the drive of the two assemblies.
• the invention proposes an advantageous embodiment in which the connecting element is pivotally mounted around a shaft with a fixed axis, the connecting axes and the fixed axis of the shaft forming a triangle, and in which the second bearings are produced at the end of a connecting rod whose other end is pivotally mounted on a third fixed bearing.
• the fixed axis shaft is advantageously driven in rotation and comprises two toothed pulleys, each equipped with a clutch and one of the pulleys is connected by a first toothed belt to the first set, the the other being connected by a second toothed belt to the second assembly.
• the shaft of fixed axis comprises a third pulley intended to allow the rotary drive of the shaft from a motor of fixed axis parallel to the fixed axis of the shaft via a third toothed belt.
• the first and second sets comprise an eccentric system
• the first set comprises a lever, connected on the one hand to the part of the machine to be moved and on the other hand to a cylindrical shaft by via a first connecting axis, parallel but offset from the cylindrical shaft
• the second assembly comprises a part driven in rotation around the axis defined by the second bearings, this part having an axis bore parallel but offset with respect to the axis defined by the second bearings and serving as a housing for bearings, and the bearings in the housing of the second set receive the cylindrical shaft which drives the lever and constitutes the connecting piece.
• the first and second sets are located side by side on a cylindrical connecting shaft.
• the part driven in rotation of the second assembly is mounted on fixed bearings. It can be provided with a peripheral toothing on which comes to mesh a pinion driven in rotation by a motor.
• this part of the second set rotates, the cylindrical connecting axis is driven and moves. This stroke is weak and is used to transmit forces.
• the stroke to move the part of the machine is carried out by driving the cylindrical connecting shaft in rotation about its axis.
• the first connecting axis is then driven and thus controls the stroke of the lever.
• a device as described above can be applied to a machine tool intended for bending a sheet, in which a sheet is held between blank clamps, and comprising a folding head for bending the sheet held between the clamps - blanks.
• a device can be used to control the folding movement, but it can also be used to control the approach and tightening movement of the blank clamps.
• a spring is advantageously placed between the frame and a part to be moved, in particular the folding head or the blank clamps. In this way, the spring can substantially balance the weight of the part to be moved and the corresponding motor can have less power for moving the same mass.
• a device according to the invention can also be applied to a machine tool intended for punching of a sheet metal, in particular when controlling the punching tool.
• Figure 1 is a block diagram explaining the operation of a punching machine equipped with devices according to the invention
• Figure 2 is a sectional view showing the operating principle of a folder equipped with devices according to the invention
• Figure 3 is a sectional view on an enlarged scale along line III-III of Figure 2;
• Figure 4 is a sectional view corresponding to the view of Figure 2 on a slightly enlarged scale, showing an alternative embodiment for the movement of a blank holder;
• Figure 5 is a view similar to Figure 4, for the same folding machine, showing a device for moving a folding head;
• Figure 6 is a sectional view schematically showing the operating principle of a punching machine, different from that shown in Figure 1;
• Figure 7 is a sectional view on an enlarged scale along the line V-V of Figure 4.
• Figure 8 is a view similar to that of Figure 7 but in another position of the tool;
• FIGS 9 to 12 are side, schematic views showing different positions of the punching tool of Figure 6;
• Figures 13 and 14 are views corresponding to Figures 4 and 5 respectively, for another embodiment; and Figure 15 is a sectional view on an enlarged scale along the section line XV-XV of Figure 14.
• FIGS 1 and 2 show examples of application of devices according to the invention.
• the following figures show in more detail the operation of such devices.
• Figure 3 shows in section a device according to the invention, for vertically moving a folding head 2 of a folder.
• the latter is intended for folding a sheet 4, held between two blanks 6.
• One of the blanks 6 is movable so as to be able to release the sheet 4 and is mounted at the end of a pivoting arm 8
• a device according to the invention controls the movement of this arm 8.
• the blank holder 6 mounted on this arm 8 comes to clamp a sheet 4 to be folded, it is unnecessary to exert a particular force during most of the stroke of this arm 8. It is only at the end of the stroke, when the blank holder 6 approaches the sheet metal 4, that an effort must be exerted to tighten the sheet metal 4 between the blank holders 6.
• the folding head 2 is moved using two devices according to the invention, one for the vertical movement of the folding head 2, the other for its horizontal movement. Here too, it is only at the end of the travel of the tool 2, when it has to bend the sheet 4, that it is necessary to exert a force on it.
• the device according to the invention comprises a first motor on which is mounted a disc 12 provided with a crank pin 14, a connecting rod 16, a crankshaft 18 connecting the connecting rod 16 to a support 20 of the folding head 2, and a second motor 22.
• the first motor 10 is mounted on a frame 24 of the folder shown in FIG. 2. It has an output shaft 26 rotating around an axis of rotation 28. The bearings of the output shaft 26 are placed at the inside the motor 10 and are not visible in the drawing.
• the disc 12 is mounted coaxially on the output shaft 26, a clutch (not shown) may be provided between the shaft 26 and the disc 12.
• the crank pin 14 has an axis parallel to the axis of the output shaft 26 This crank pin defines the first connecting axis 30 with the connecting rod 16, which is mounted on this crank pin 14 by one of its ends.
• the other end of the connecting rod 16 is in the form of a fork with two branches, between which the support 20 of the folding head takes place.
• Each of the branches has a bore serving as a bearing 32 for the crankshaft 18.
• This axis 34 constitutes the second connecting axis.
• the crankshaft 18 comprises two connecting rod bearings 36 each mounted in a bearing 32 and connected together by a crankshaft bearing 38 on which the support 20 of the folding head is mounted.
• the axis 40 of the crankshaft bearing is parallel to the connecting axis 34 but offset with respect thereto.
• the second engine 22 is mounted integral with the support 20 of the folding head and its output shaft is mounted coaxially with the crankshaft bearing 38, directly or with, for example, the interposition of a clutch not shown.
• the axes 28,40 of the first and second motors and the connecting axes 30,34 are parallel.
• the maximum stroke of the connecting rod is equal to twice the offset existing between the axis 28 of the first engine and the first connecting axis 30.
• the second engine 22, when it rotates the crankshaft 18, causes a relative movement between the connecting rod 16 and the support 20 of the folding head. This displacement is at most equal to twice the distance between the second connecting axis 34 and the axis 40 of the crankshaft bearing.
• the first motor 10 is used for moving the folding head 2 towards and away from the sheet metal 4.
• the second motor 22 is used for folding the sheet metal 4. So that the torque exerted by the second motor 22 is sufficient to bend the sheet, the distance separating the second connecting axis 34 from the axis 40 of the crankshaft bearing is small.
• the axis 28 of the first motor is placed so that the line of action of the forces exerted on the sheet 4 intersects this axis 28, so that the torque exerted on this axis 28 by reaction of the forces exerted on the sheet is no.
• the device is stable while forces are exerted on the sheet and the forces exerted on the bearings are optimized.
• Figures 4 and 5 show another embodiment of a device according to the invention for moving the arm 8 and the folding head 2.
• elements similar to those of Figures 2 and 3 have the same references.
• Figure 4 there are two eccentric systems similar to those described above.
• the main difference between the variant shown in Figures 4 and 5 and that of Figures 2 and 3 is that a single motor, not shown, is sufficient for driving the two eccentric systems.
• the connecting rod 16 is then replaced by a connecting piece 64, having three axes, while the connecting rod 16 has only two.
• the connecting piece 64 is of substantially triangular shape, bearings located at the vertices of the triangle formed by this piece.
• a toothed pulley 70 is mounted coaxially with the axis 28 on a bearing produced at the end of a connecting rod 66.
• the other end of the connecting rod 66 is pivotally mounted on a support 68, fixed relative to the frame 24 of the folder.
• a first toothed belt 72 drives the toothed pulley 70.
• the third top of the connecting piece 64 is pivotally mounted on a shaft 80 of fixed axis.
• This shaft 80 carries three pulleys and the connecting piece 64. It is mounted on bearings integral with the frame 24 and not shown in the drawing.
• a pulley 82 is driven by a third toothed belt 84. The other two pulleys each drive a toothed pulley 70,74 using one of the belts 72,76 mentioned above.
• a motor, not shown, fixed on a support 86 integral with the frame 24 drives the toothed belt 84 and therefore the pulley 82.
• the latter is for example keyed onto the shaft 80, so that there is no possibility of angular offset between the pulley 82 and the shaft 80.
• the two other pulleys of the shaft 80 are each provided with a clutch so that they only drive the belts 72 and / or 76 only when it is necessary to move the arm 8 and / or to exert a force on it.
• the device shown in Figure 5 is quite similar to that shown in Figure 4 and which has just been described. The differences are related only to a different orientation of the device which allows the folding head 2 to be moved vertically.
• FIG. 6 represents in section and schematically a punching machine whose tool, a punch, is driven by a device according to the invention, different from that of FIG. 3.
• the device comprises a first crankshaft 142, a connecting rod 116 and a second crankshaft 152.
• Each crankshaft is provided with a toothed pulley 144,146, driven in rotation by a toothed belt 148.
• the first crankshaft 142 is mounted on a fixed frame 124 of the punching machine. Two bearings, defining a first axis 128, are produced in the frame 124. In each of these bearings is a crank pin 150 of the crankshaft 142. These two crank pins 150 are connected together by a bearing 114, the axis 130 of which corresponds to the first connecting rod connecting axis. This connecting axis 130 is offset from the axis 128 of the crank pins 150 but is parallel thereto.
• the connecting rod 116 is mounted on the bearing 114 by one of its ends. Its other end is mounted on a connecting rod bearing 154, of axis 134, of the second crankshaft 152.
• the latter also comprises two crank pins 156 coaxial, defining a crankshaft axis 140.
• the two crank pins 156 are mounted in a bore produced in the punch 102.
• the latter has at one of its ends a fork shape, making it possible to accommodate one end of the connecting rod 116 between the branches of the fork.
• the toothed pulley 144 of the first crankshaft 142 is mounted on the first connecting rod connecting axis 130, while the second toothed pulley 146 of the second crankshaft is mounted on the second connecting rod connecting axis 134.
• the two toothed pulleys 144,146 are in a same plan. They are driven by the same toothed belt 148.
• a third toothed pulley 158 mounted in the same plane as the other two pulleys 144,146, is rotated directly ( Figures 9 to 12) or indirectly ( Figure 6) by an electric motor 160 fixed on the frame 124.
• This motor 160 is fixed on the axis of the third pulley 158 or else of another pulley in connection with this third pulley.
• the engine can be multiplied at will.
• Figures 9 to 12 illustrate the operation of the device shown in section in Figures 7 and 8.
• the arrows show the direction of rotation of the toothed pulleys 144, 146 and 158. They rotate clockwise.
• Figure 9 corresponds to the position of Figure 7.
• the punch 102 which is guided relative to the frame 124 in a bearing 162, is then in its retracted position.
• the first pulley 144 rotates, it drives the first crankshaft 142 in rotation.
• the latter rotates around its axis 128 defined by its crank pins 150.
• the connecting axis of the connecting rod 130 then rotates around the axis of rotation 128 of the crankshaft.
• the connecting rod 116 is driven by this downward movement, carrying with it the tool 102, the second crankshaft 152 and the associated pulley 146.
• the second pulley 146 also rotates, causing the second crankshaft to rotate about the connecting axis 134. This rotation induces a rotation of the crankshaft axis 140 around the connecting axis 134, thereby moving the l tool 102 of the connecting rod 116.
• the pulleys 144 and 146 have the same number of teeth and rotate synchronously.
• the punch 102 gradually leaves the frame 124 from the position shown in Figures 7 and 9 to the position of Figures 8 and 11. Between these two positions, the pulleys 144 and 146 have rotated 180 °.
• Figure 10 shows the relative positions of the different parts of the device after a 90 ° rotation from the initial position ( Figures 7 and 9).
• each axis 128, 140 defined by the crank pins of a crankshaft and the corresponding connecting axis 130, 134. This last distance determines the stroke of the tool. If necessary, it is possible to add a second connecting rod with a third crankshaft.
• FIG. 2 shows a different application of a device as described above with reference to FIGS. 6 to 12.
• This device 101 controls the horizontal movement of the folding head 2.
• Figure 1 shows two devices similar to that of Figure 6 driven by a single motor. The latter drives two pulleys equivalent to the third pulley 158 in FIG. 6.
• Figures 13 to 15 show another embodiment applied to a folder.
• elements similar to those in Figures 1 to 5 bear the same reference increased by 200.
• FIG. 13 shows in section a device according to the invention, making it possible to vertically move a folding head 202 of a folder.
• the latter is intended for folding a sheet 204, held between two blank clamps 206.
• One of the blank clamps 206 is movable so as to be able to release the sheet 204 and is mounted at the end of a pivoting arm 208
• a device according to the invention controls the movement of this arm 208.
• the folding head 202 is moved using two devices according to the invention, one for its vertical displacement, the other for its displacement horizontal ( Figure 14).
• the device 101 for horizontal displacement has been described above.
• FIG. 15 shows in section the device according to the invention making it possible to vertically move the folding head 202. This device is similar to that making it possible to move the blank holder 206.
• the device comprises a lever 278 connected by one of its ends to the folding head 202 (or to the blank holder 206).
• the other end of the lever 278 is mounted by means of a connecting finger 214 of axis 230 on a cylindrical connecting shaft 216, of axis 228.
• the cylindrical connecting shaft 216 rotates around its axis , it drives with it the connecting finger 214 by means of a driving part 288 keyed to the shaft 216.
• Bearings 290 allow relative rotation between the connecting finger 214 and the driving part 288.
• the cylindrical connecting shaft 216 is mounted on bearings 292 defining first bearings. These bearings are mounted in a bore 294 of axis 234. This axis 234 coincides with the axis 228 of the cylindrical connecting shaft 216.
• the bore 294 is produced in a toothed wheel 296 of axis 240, parallel to the axis 234 of the bore 294, but offset with respect thereto.
• the toothed wheel 296 therefore has an eccentric. It is guided in rotation using a second bearing defined by ball bearings 298.
• ball bearings are mounted in a fixed bore relative to the frame 224 of the folder.
• a pinion 300 driven by a motor not shown in the drawing, is mounted on the frame 224 of the folder and meshes with the toothed wheel 296.
• FIG 13 two springs 302 and 304 have been shown.
• the first spring 302 is disposed between the arm 208 and the frame 224 of the folder.
• the stiffness of the spring 302 and its compression are determined so that the force exerted by this spring 302 compensates substantially the weight of the arm 208.
• the power of the motor driving the lever 278 can be significantly reduced compared to a machine as shown for example in Figure 4 and not having such a spring.
• the second spring 304 has a similar role. It is mounted between the folding head 202 and the frame 224 of the machine. Like the spring 302 for the arm 208, it makes it possible to balance the weight of the folding head 202.
• the drive motor corresponding to the movement of the folding head 202 without exerting any effort can therefore be a motor of lower power , compared to a folding machine of this type but without spring.
• the cylindrical connecting shaft 216 To move the part of the folder, folding head 202 or blank holder 206, without exerting any effort, the cylindrical connecting shaft 216 is rotated. This rotation causes a displacement of the lever 278 which describes a movement similar to that of a connecting rod relative to a crankshaft.
• the cylindrical connecting shaft 216 does not allow a rotation of 360 °, but allows an angular travel of more than 180 °, thus making it possible to exploit to the maximum the theoretical travel of the end of the lever not connected to this tree.
• the toothed wheel 296 When it comes to exerting a force, the toothed wheel 296 is driven by the pinion 300. The toothed wheel 296 then pivots around the axis 240.
• the axis 234 of the bore 294 therefore moves in the plan of Figure 15, due to its eccentricity. This movement is transmitted via the cylindrical connecting pin 216 and the connecting finger 214 to the lever 278.
• an electric motor it is possible to exert a significant effort.
• the torque to be supplied by the drive means in the cited applications may very well be delivered by electric motors similar to those already used in the construction of machine tools.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmission Devices (AREA)
• Vehicle Body Suspensions (AREA)
• Manipulator (AREA)
• Press Drives And Press Lines (AREA)
• Support Of The Bearing (AREA)

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• 1996
  • 1996-07-05 FR FR9608639A patent/FR2750625B1/fr not_active Expired - Fee Related
• 1997
  • 1997-07-07 DE DE69702860T patent/DE69702860T2/de not_active Expired - Fee Related
  • 1997-07-07 EP EP97931892A patent/EP0918580B1/de not_active Expired - Lifetime
  • 1997-07-07 AT AT97931892T patent/ATE195447T1/de not_active IP Right Cessation
  • 1997-07-07 WO PCT/FR1997/001226 patent/WO1998001244A1/fr active IP Right Grant

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