MATERIAL FORMING

Abstract

A method for material forming uses a movable tool and a drive unit the method including moving the drive unit to provide kinetic energy to the tool, for the tool to strike a work material, so as to form the work material the method including providing an impact head between the drive unit and the movable tool, and providing the kinetic energy to the tool by the drive unit striking the impact head, the impact head (extending in the direction of the stroke from an impact end to a base region, where the base region is closer to the tool than the impact end. The method includes arranging the impact head so that the impact end has laterally, in relation to the direction of the stroke, a smaller extension than the base region.

Claims

1. A method for material forming, by means of a movable tool and a drive unit the method comprising moving the drive unit to provide kinetic energy to the tool, for the tool to strike a work material, so as to form the work material, the method comprising providing an impact head between the drive unit and the movable tool, and providing the kinetic energy to the tool by the drive unit striking the impact head the impact head extending in the direction of the stroke from an impact end to a base region, where the base region is closer to the tool than the impact end, wherein arranging the impact head so that the impact end has laterally, in relation to the direction of the stroke, a smaller extension than the base region.

2. A method according to claim 1, wherein perimeter edges of the base region of the impact head are, in the stroke direction, outside of, and/or substantially coinciding with, perimeter edges of a working surface of the tool which comes into contact with the work material at the stroke.

3. A method according to claim 1, wherein the impact head narrows off in the direction away from the tool so as for the impact head to transfer kinetic energy towards the perimeter edges of the tool by a stroke of the drive unit to the impact head, wherein the impact head is tapered in a direction away from the work material, so as for the impact head to spread kinetic energy evenly to the tool from the impact end to the base region.

4. A method according to claim 1, comprising providing the impact head and the tool with a respective collar at an interface between the impact head and the tool, the collar of the tool surrounding, as seen in the direction of the stroke, a working surface of the tool which comes into contact with the work material at the stroke, wherein a first portion of the impact head extends from the collar of the impact head, to the impact end of the impact head, wherein the first portion presents a perimeter edge at the collar, which, as seen in the direction of the stroke, substantially coincides with the working surface.

5. A method according to claim 4, comprising arranging the first portion so that the first portion has laterally, in relation to the direction of the stroke, a smaller extension at the impact end than at the impact head collar.

6. A method according to claim 4, comprising arranging the collars in a recess of a frame.

7. A method according to claim 4, comprising arranging a first dampening element (between a surface of the impact head collar, facing away from the work material, and a shoulder of a frame the method further comprising arranging a second dampening element between a surface of the tool collar, facing away from the impact head, and a shoulder of a frame, wherein the collars are restrained between the dampening elements.

8. An apparatus for material forming, by means of a tool and a drive unit, the apparatus being arranged to move the drive unit to provide kinetic energy to the tool for the tool to strike a work material, so as to form the work material, the apparatus being provided with an impact head between the drive unit and the movable tool, and the apparatus being arranged to provide the kinetic energy to the tool by the drive unit striking the impact head the impact head extending in the direction of the stroke from an impact end to a base region where the base region is closer to the tool than the impact end, wherein the impact head is arranged so that the impact end as laterally, in relation to the direction of the stroke, a smaller extension than the base region.

9. An apparatus according to claim 8, wherein the apparatus is arranged so as for perimeter edges of the base region of the impact head to be, in the stroke direction, outside of, and/or substantially coinciding with, perimeter edges of a working surface of the tool which is arranged to come into contact with the work material at the stroke.

10. An apparatus according to claim 8, wherein the impact head narrows off in the direction away from the tool 4), and the apparatus is arranged so as for the impact head to transfer kinetic energy towards the perimeter edges of the tool by a stroke of the drive unit to the impact head, wherein the impact head is tapered in a direction away from the tool and the apparatus is arranged so as for the impact head o spread kinetic energy over the tool rom the impact end (46) to the base region.

11. An apparatus according to claim 8, wherein the impact head and the tool comprises a respective collar at an interface between the impact head and the tool, the collar of the tool surrounding, as seen in the direction of the stroke, a working surface of the tool which is arranged to come into contact with the work material at the stroke, wherein a first portion of the impact head extends from the collar of the impact head, to the impact end of the impact head, wherein the first portion presents a perimeter edge at the collar, which, as seen in the direction of the stroke, substantially coincides with the working surface.

12. An apparatus according to claim 11, wherein the first portion is arranged so that the first portion has laterally, in relation to the direction of the stroke, a smaller extension at the impact end than at the impact head collar.

13. An apparatus according to claim 11, wherein the collars are arranged in a recess of a frame.

14. An apparatus according to claim 11, wherein a first dampening element is arranged between a surface of the impact head collar, facing away from the work material, and a shoulder of a frame , wherein a second dampening element is arranged between a surface of the tool collar, facing away from the impact head, and a shoulder of a frame, wherein the collars are arranged to be restrained between the dampening elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Below, embodiments of the invention will be described with reference to the drawings, in which:

[0048] FIG. 1 shows a partially sectioned, schematic view of an apparatus for material forming according to an embodiment of the invention,

[0049] FIG. 2 shows schematically a sectioned perspective view of a part of the apparatus in FIG. 1,

[0050] FIG. 3 shows a part of FIG. 2 in greater detail,

[0051] FIG. 4 is a flow chart depicting steps in the method according to an embodiment of the invention, and

[0052] FIG. 5 shows an apparatus for material forming according to another embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0053] FIG. 1 shows an apparatus for material forming according to an embodiment of the invention. According embodiments of the invention, the apparatus comprises a tool housing holding a movable impact head and tool combination 4. The tool housing may form a part of a frame 30. The apparatus further comprises a drive unit in the form of a plunger 2, as shown in FIG. 1. In the embodiment shown in FIG. 1, a drive assembly comprises a cylinder housing 1. Further, the drive assembly comprises the plunger 2, that is arranged in the cylinder housing 1. The cylinder housing 1 may be mounted to the frame 30.

[0054] An anvil 106 is fixed to the frame. A fixed tool 5 is mounted to the anvil 106. The fixed tool 5 is mounted to an upper side of the anvil 106. A movable impact head and tool combination 4, described closer below with reference to FIG. 2, is located above the fixed tool 5. The tools 4, 5 present complementary surfaces facing each other. A work material W is removably mounted to the fixed tool 5. The work material W may be mounted to the fixed tool 5 in any suitable manner, e.g. by clamping, or with vacuum. The work material W could be of a variety of types, for example a piece of sheet metal. It should be noted that in some embodiments, what is herein referred to as a fixed tool could also be movable.

[0055] The plunger 2 is arranged to move towards and away from the fixed tool 5, as described closer below. The plunger 2 is arranged to be driven by a hydraulic system 6. With respect to the plunger 2, driven by a hydraulic system pressure, reference is made to the disclosure of EP3122491B1, which is hereby incorporated by reference.

[0056] The apparatus is arranged to move the plunger 2 to provide kinetic energy to the movable impact head and tool combination 4, for the movable impact head and tool combination 4 to strike a work material, so as to form the work material W.

[0057] Before providing kinetic energy to the movable impact head and tool combination 4 by moving or accelerating the plunger 2 to strike the movable impact head and tool combination 4, the movable impact head and tool combination 4 may be positioned at any suitable distance from the work material W. As an example, the distance may be 1-10 mm, e.g. 1.5-5 mm, or 2-3 mm.

[0058] The apparatus is arranged so as for a return movement of the movable impact head and tool combination 4, away from the work material W, to be dampened, after the strike of the work material W by the movable impact head and tool combination 4. Where the apparatus is arranged so as for the movable impact head and tool combination 4 to be dampened, the apparatus may be arranged to prevent bouncing of the movable impact head and tool combination 4 its return movement.

[0059] FIG. 2 shows schematically the movable impact head and tool combination 4, and surrounding parts, of the apparatus in FIG. 1. The frame 30 may comprise a tool housing 34. The fixed tool 5 is provided in a tool support 51.

[0060] FIG. 2 shows, for the sake of this presentation, the tool housing 34 is presented as separated from the tool support 51. However, when the apparatus is in use, the tool housing 34 would be in contact with the tool support 51. Thus, in FIG. 2 depicts the impact and tool combination 4 at a distance from the fixed tool 5. Thus, in FIG. 2, the impact head and tool combination 4 is illustrated as being positioned at a significant distance from the work material W. However, for striking the work material, the impact head and tool combination 4 is in this example positioned much closer towards the work material W. Nevertheless, for changing the work material, the tool housing 34 may be separated from the tool support 51, e.g. as depicted in FIG. 2. For example, this separation may be assisted by a guiding arrangement, arranged to guide the movement of the tool housing.

[0061] Reference is made also to FIG. 3. A dampening arrangement 32 may be mounted to the frame 30, in this example to the tool housing 34. The impact head and tool combination 4 may be arranged to be dampened by means of the dampening arrangement 32. The dampening arrangement 32 may comprise a first dampening element 32 arranged between the tool housing 34 and a surface 36 of the impact head and tool combination 4 facing away from the work material W. The tool housing 34 may be provided with a shoulder 38. The impact head and tool combination 4 can be provided with a foot portion 40, provided laterally, in relation to a direction of the strike D of the work material, outside a surface S, of the impact head and tool combination 4, arranged to contact the work material W when the work material is struck. The shoulder 38 of the tool housing is in this example arranged to extend over a surface of the foot portion 40 facing away from the work material W.

[0062] Preferably, the dampening arrangement 32 comprises a second dampening element 32 arranged between the tool housing 34 and a surface 42 of the impact head and tool combination 4 facing towards the work material W. The impact head and tool combination 4 may be arranged in restrained engagement between the dampening elements 32, 32. Preferably, the first dampening element 32 is provided with a lower hardness than the second dampening element 32.

[0063] The dampening elements 32, 32 may be in any suitable material, for example polyurethane, or rubber. The material may be elastic. The material may have a dampening quality. The material may be suitable to dissipate the kinetic energy of the impact head and tool combination 4. Alternatively, the dampening elements 32, 32 may be provided as damping springs. In this example, the dampening elements are provided as elongated strips 32, 32. The strips 32, 32 have a rectangular cross-section. The strips are partially fitted in a respective groove of the tool housing. Alternatively, or in addition, the strips could be partially fitted in a respective groove in the foot portion 40. The strips are 32, 32 laterally positioned externally of a working surface S of the impact head and tool combination 4. As seen in the direction of the strike D, the strips 32, 32 surround the working surface S. Alternatively, one of, or each of, the dampening elements 32, 32 may be provided a plurality of separated elements.

[0064] The material of the first dampening element may be elastic. The material may have a dampening quality. The material may be suitable to dissipate the kinetic energy of the impact head and tool combination 4. The dimensions, and the material, of the first damping element, are preferably adapted to avoid excessive heat generation due to the dissipation of kinetic energy of the impact head and tool combination.

[0065] The material of the second dampening element may be elastic. The material may further have a dampening quality. The dimensions, and the material, of the second damping element, are preferably adapted to avoid excessive heat generation during its deformation in the striking process.

[0066] In the embodiment shown in FIGS. 1 and 2, the impact head and tool combination 4 comprises a tool 4 to strike the work material W. The impact head and tool combination 4 further comprises an impact head 4 to receive a strike from the moving drive unit 2. The tool 4 and the impact head 4 may be fixed to each other by attachment means provided adjacent the perimeter edges of the tool and the impact head, e.g. by a bolt connection. Preferably, the attachment means of the tool 4and the impact head 4 are positioned within a recess 44 of the tool housing 34 formed by the shoulder 38. Said dampening elements 32, 32 are preferably also provided within the recess 44. The recess 44 is laterally positioned externally of the working surface S of the impact head and tool combination 4. As seen in the direction of the strike D, the recess 44 surrounds the working surface S.

[0067] Preferably, the impact head 4 and the tool 4 comprises a respective collar 50, 52 at an interface between the impact head 4 and the tool 4, the collar 52 of the tool 4 surrounding, as seen in the direction of the stroke D, the working surface S of the tool which is arranged to come into contact with the work material W at the stroke. Said collars 50, 52 may thereby form said foot portion 40. Both collars 50, 52 may extend into the recess 44. The collar 50 of the impact head 4 may be arranged to be in contact with the first damping element 32. The collar 52 of the tool 4 may be arranged to be in contact with the second damping element 32. Bolts of said bolt connection may extent through the collars 50. 52.

[0068] At a strike, the impact head and tool combination 4 moves towards the work material W, and thereby it compresses the second dampening element 32. When the work material W has been struck, elastic energy in the second dampening element 32 moves the impact head and tool combination 4 away from the work material W. Thereby, the first dampening element 32 dampens the movement of the impact head and tool combination 4, as it moves away from the work material W. Thereby, a closely controlled reciprocating movement of the impact head and tool combination 4 at a strike is accomplished.

[0069] The impact head 4 extends in the direction of the stroke D from an impact end 46 to a base region 48, where the base region 48 is closer to the tool 4 than the impact end 46. The impact head 4 is arranged so that the impact end 46 has laterally, in relation to the direction of the stroke D, a smaller extension than the base region 48. The base region 48 is in this example not at the interface of the impact head 4 with the tool 4. The base region is at a distance from this interface. The base region 48 is indicate with a broken line in FIG. 2.

[0070] As suggested, the impact head 4 and the tool 4 may be mounted to the frame 30 and may be arranged to be movable in relation to the tool housing 34 of the frame 30. Preferably, the apparatus is arranged so as for perimeter edges of the base region 48 of the impact head 4 to, in the stroke direction D, substantially coincide with, perimeter edges of the working surface S of the tool 4 which is arranged to come into contact with the work material W at the stroke. Suitably, the impact head 4 narrows off in the direction away DA from the tool 4.The apparatus in this example is arranged so as for the impact head 4 to transfer kinetic energy, from a stroke of the plunger 2 to the impact head 4, directly to the entire working surface S. A first portion 54 the impact head 4, between the impact end and the base region 48, is tapered in a direction away DA from the tool 4. The apparatus is arranged so as for the impact head 4 to spread kinetic energy directly over the working surface S from the impact end 46.

[0071] As suggested, the impact head 4 and the tool 4 in this example comprise a respective collar 50, 52 at an interface between the impact head 4 and the tool 4. The collar 52 of the tool 4 surrounds, as seen in the direction of the stroke D, the working surface S of the tool which is arranged to come into contact with the work material W at the stroke. The first portion 54 of the impact head 4 extends from the collar 50 of the impact head 4, to the impact end 46 of the impact head. The first portion 54 presents a perimeter edge at the collar 50, i.e. at the base region 48, which, as seen in the direction of the stroke D, substantially coincides with the working surface S. The first portion 54 may be arranged so that the first portion 54 has laterally, in relation to the direction of the stroke D, a smaller extension at the strike end 46 than at the impact head collar 50. As suggested, the collars 50, 52 are in this example arranged in the recess 44 of the tool housing 34. Thereby the dampening elements 32, 32 may be separated from, and not interfere with, the direct transfer of kinetic energy from the impact end 46 to the working surface S.

[0072] FIG. 4 is a flow chart depicting steps in the method according to the embodiment of the invention described with reference to FIG. 1-3. The method comprises providing S1 an impact head and tool combination 4, with a tool, and with an impact head 4 which narrows off in the direction away from the tool 4. Subsequently, the impact head and tool combination 4 is arranged S2 so as to be restrained between first and second dampening elements 32, 32. Subsequently the drive unit is moved S3 so as to strike the impact head, thereby providing kinetic energy to the impact head and tool combination 4. Thereby, the impact head 4 transfers kinetic energy towards the perimeter edges of the tool. The method further comprises allowing S4 the impact head and tool combination, thus provided with kinetic energy, to strike the work material W, so as to form the work material. Thereupon, a return movement of the movable impact head and tool combination 4, away from the work material, is enabled or assisted S5 by a spring action of the second damping element 32. Further, the return movement of the movable impact head and tool combination 4, is dampened S6 by the first dampening element 32.

[0073] Preferably, the drive unit 2, in this example the plunger, moves, upon the impact with the impact head, away from the work material. Thus, the drive unit 2 may be arranged to move, upon the impact with the impact head, away from the work material. The drive unit 2 may be arranged to bounce, upon the impact with the impact head. The movement of the drive unit 2, upon the impact with the impact head, may be secured by an appropriate selection of the mass of the drive unit, the mass of the impact head and tool combination. The movement of the drive unit 2, upon the impact with the impact head, may be further secured by an appropriate selection of the driving force, e.g. the hydraulic force, on the dive unit, at the time of impact with the impact head.

[0074] The movement of the drive unit away from the work material, upon the impact with the impact head, provides for avoiding that the impact head and tool combination contacts the drive unit during the return movement of the impact head and tool combination.

[0075] FIG. 5 shows an apparatus for high velocity material forming according to another embodiment of the invention. The same reference numerals are used for the corresponding features as shown and described with reference to FIGS. 1 and 2. The apparatus comprises a frame 30. The frame is supported by a plurality of support devices 110. An anvil 106 is fixed to the frame. In this embodiment, the anvil 106 is fixed at the top of the frame 30.

[0076] A tool, herein referred to as a fixed tool 5, is mounted to the anvil. The fixed tool 5 is mounted to a lower side of the anvil 106. A movable impact head and tool combination 4, described closer below, is located below the fixed tool 5. The impact head and tool combination 4 and the fixed tool 5 present complementary surfaces facing each other. A workpiece W is removably mounted to the fixed tool 5. The workpiece W may be mounted to the fixed tool 5 in any suitable manner, e.g. by clamping, or with vacuum. The workpiece W could be of a variety of types, for example a piece of sheet metal.

[0077] In the embodiment shown in FIG. 5, a drive assembly comprising a cylinder housing 102 is mounted to the frame 30. Further, the drive assembly comprises a plunger 101 that is arranged in the cylinder housing 102. The plunger 101 is elongated, and has, as understood from the description below, a varying width along its longitudinal axis. Preferably, any cross-section of the plunger is circular. The plunger 101 is arranged to move towards and away from the fixed tool 5, as described closer below.

[0078] In this embodiment, the impact head and tool combination 4 is in contact with the plunger 101 as the plunger is accelerated by means of a hydraulic system 6. Therefore, there is no impact between the plunger 101 and the impact head and tool combination 4. Therefore, what is here referred to as an impact head and tool combination 4 may be provided with an impact head forming merely a support for a tool of the impact head and tool combination 4. Before providing kinetic energy to the tool by moving or accelerating the plunger 101, the tool may be positioned at a distance of at least 12 mm, e.g. 50, 100, or 200 mm, from the work material W.

[0079] The plunger 101 is arranged to accelerate the impact head and tool combination 4 towards the fixed tool. The plunger 101 is arranged to be driven by the hydraulic system 6. Before the impact head and tool combination 4 strikes the work material W, the plunger 101 decelerated so that the impact head and tool combination 4 continues by inertia towards the work material W.

[0080] When the impact head and tool combination 4 has struck the work material W, the impact head and tool combination 4 moves away from the work material W, and towards the plunger 101 by gravity. To brake the return movement of the movable impact head and tool combination 4 as it approaches the plunger 101, a damping arrangement 32 is provided. In this example, the damping arrangement comprises a damper mounted to the plunger 101. The damper is mounted at the top end of the plunger. The damper may be of any suitable kind, e.g. hydraulic or pneumatic. Alternatively, or in addition, the damper may comprise an elastic element, such as a plate spring. In some embodiments, the damping arrangement may comprise a damper mounted to the impact head and tool combination 4. In further embodiments, the damping arrangement may comprise a damper mounted to the frame 30. The damping arrangement will effectively brake the return movement of the movable tool. The damping arrangement may also prevent bouncing of the movable impact head and tool combination 4 at the end of its return movement. Thereby, the movable impact head and tool combination 4 may be brought back to rest on the plunger in a controlled manner.

[0081] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.