Patent ID: 12220741

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG.1shows an apparatus for material forming according to an embodiment of the invention. The apparatus comprises a tool housing holding a movable impact head and tool combination4. The tool housing may form a part of a frame30. The apparatus further comprises a drive unit in the form of a plunger2, as shown inFIG.1. In the embodiment shown inFIG.1, a drive assembly comprises a cylinder housing1. Further, the drive assembly comprises the plunger2, that is arranged in the cylinder housing1. The cylinder housing1may be mounted to the frame30.

An anvil106is fixed to the frame. A fixed tool5is mounted to the anvil106. The fixed tool5is mounted to an upper side of the anvil106. A movable impact head and tool combination4, described below with reference toFIG.2, is located above the fixed tool5. The tools4,5present complementary surfaces facing each other. A work material W is removably mounted to the fixed tool5. The work material W may be mounted to the fixed tool5in 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.

The plunger2is arranged to move towards and away from the fixed tool5, as described closer below. The plunger2is arranged to be driven by a hydraulic system6. With respect to the plunger2, driven by a hydraulic system pressure, reference is made to the disclosure of EP3122491 B1, which is hereby incorporated by reference.

The apparatus is arranged to move the plunger2to provide kinetic energy to the movable impact head and tool combination4, for the movable impact head and tool combination4to strike a work material, so as to form the work material W.

Before providing kinetic energy to the movable impact head and tool combination4by moving or accelerating the plunger2to strike the movable impact head and tool combination4, the movable impact head and tool combination4may 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.

The apparatus is arranged so as for a return movement of the movable impact head and tool combination4, away from the work material W, to be dampened, after the strike of the work material W by the movable impact head and tool combination4. Where the apparatus is arranged so as for the movable impact head and tool combination4to be dampened, the apparatus may be arranged to prevent bouncing of the movable impact head and tool combination4its return movement.

FIG.2shows schematically the movable impact head and tool combination4, and surrounding parts, of the apparatus inFIG.1. The frame30may comprise a tool housing34. The fixed tool5is provided in a tool support51.

FIG.2shows, for the sake of this presentation, the tool housing34is presented as separated from the tool support51. However, when the apparatus is in use, the tool housing34would be in contact with the tool support51. Thus, inFIG.2depicts the impact and tool combination4at a distance from the fixed tool5. Thus, inFIG.2, the impact head and tool combination4is illustrated as being positioned at a significant distance from the work material W. However, for striking the work material, the impact head and tool combination4is in this example positioned much closer towards the work material W. Nevertheless, for changing the work material, the tool housing34may be separated from the tool support51, e.g. as depicted inFIG.2. For example, this separation may be assisted by a guiding arrangement, arranged to guide the movement of the tool housing.

Reference is made also toFIG.3. A dampening arrangement32may be mounted to the frame30, in this example to the tool housing34. The impact head and tool combination4may be arranged to be dampened by means of the dampening arrangement32. The dampening arrangement32may comprise a first dampening element32′ arranged between the tool housing34and a surface36of the impact head and tool combination4facing away from the work material W. The tool housing34may be provided with a shoulder38. The impact head and tool combination4can be provided with a foot portion40, 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 combination4, arranged to contact the work material W when the work material is struck. The shoulder38of the tool housing is in this example arranged to extend over a surface of the foot portion40facing away from the work material W.

Preferably, the dampening arrangement32comprises a second dampening element32″ arranged between the tool housing34and a surface42of the impact head and tool combination4facing towards the work material W. The impact head and tool combination4may be arranged in restrained engagement between the dampening elements32′,32″. Preferably, the first dampening element32′ is provided with a lower hardness than the second dampening element32″.

The dampening elements32′,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 combination4. Alternatively, the dampening elements32′,32″ may be provided as damping springs. In this example, the dampening elements are provided as elongated strips32′,32″. The strips32′,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 portion40. The strips are 32′,32″ laterally positioned externally of a working surface S of the impact head and tool combination4. As seen in the direction of the strike D, the strips32′,32″ surround the working surface S. Alternatively, one of, or each of, the dampening elements32′,32″ may be provided a plurality of separated elements.

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 combination4. 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.

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.

In the embodiment shown inFIGS.1and2, the impact head and tool combination4comprises a tool4′ to strike the work material W. The impact head and tool combination4further comprises an impact head4″ to receive a strike from the moving drive unit2. The tool4′ and the impact head4″ 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 tool4′ and the impact head4″ are positioned within a recess44of the tool housing34formed by the shoulder38. Said dampening elements32′,32″ are preferably also provided within the recess44. The recess44is laterally positioned externally of the working surface S of the impact head and tool combination4. As seen in the direction of the strike D, the recess44surrounds the working surface S.

Preferably, the impact head4″ and the tool4′ comprises a respective collar50,52at an interface between the impact head4″ and the tool4′, the collar52of the tool4′ 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 collars50,52may thereby form said foot portion40. Both collars50,52may extend into the recess44. The collar50of the impact head4″ may be arranged to be in contact with the first damping element32′. The collar52of the tool4′ may be arranged to be in contact with the second damping element32″. Bolts of said bolt connection may extent through the collars50,52.

At a strike, the impact head and tool combination4moves towards the work material W, and thereby it compresses the second dampening element32″. When the work material W has been struck, elastic energy in the second dampening element32″ moves the impact head and tool combination4away from the work material W. Thereby, the first dampening element32′ dampens the movement of the impact head and tool combination4, as it moves away from the work material W. Thereby, a closely controlled reciprocating movement of the impact head and tool combination4at a strike is accomplished.

The impact head4″ extends in the direction of the stroke D from an impact end46to a base region48, where the base region48is closer to the tool4′ than the impact end46. The impact head4″ is arranged so that the impact end46has laterally, in relation to the direction of the stroke D, a smaller extension than the base region48. The base region48is in this example not at the interface of the impact head4″ with the tool4′. The base region is at a distance from this interface. The base region48is indicate with a broken line inFIG.2.

As suggested, the impact head4″ and the tool4′ may be mounted to the frame30and may be arranged to be movable in relation to the tool housing34of the frame30. Preferably, the apparatus is arranged so as for perimeter edges of the base region48of the impact head4″ to, in the stroke direction D, substantially coincide with, perimeter edges of the working surface S of the tool4′ which is arranged to come into contact with the work material W at the stroke. Suitably, the impact head4″ narrows off in the direction away DA from the tool4′. The apparatus in this example is arranged so as for the impact head4″ to transfer kinetic energy, from a stroke of the plunger2to the impact head4″, directly to the entire working surface S. A first portion54the impact head4″, between the impact end and the base region48, is tapered in a direction away DA from the tool4′. The apparatus is arranged so as for the impact head4″ to spread kinetic energy directly over the working surface S from the impact end46.

As suggested, the impact head4″ and the tool4′ in this example comprise a respective collar50,52at an interface between the impact head4″ and the tool4′. The collar52of the tool4′ 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 portion54of the impact head4″ extends from the collar50of the impact head4″, to the impact end46of the impact head. The first portion54presents a perimeter edge at the collar50, i.e. at the base region48, which, as seen in the direction of the stroke D, substantially coincides with the working surface S. The first portion54may be arranged so that the first portion54has laterally, in relation to the direction of the stroke D, a smaller extension at the strike end46than at the impact head collar50. As suggested, the collars50,52are in this example arranged in the recess44of the tool housing34. Thereby the dampening elements32′,32″ may be separated from, and not “interfere” with, the direct transfer of kinetic energy from the impact end46to the working surface S.

FIG.4is a flow chart depicting steps in the method according to the embodiment of the invention described with reference toFIG.1-3. The method comprises providing S1an impact head and tool combination4, with a tool, and with an impact head4″ which narrows off in the direction away from the tool4′. Subsequently, the impact head and tool combination4is arranged S2so as to be restrained between first and second dampening elements32′,32″. Subsequently the drive unit is moved S3so as to strike the impact head, thereby providing kinetic energy to the impact head and tool combination4. Thereby, the impact head4″ transfers kinetic energy towards the perimeter edges of the tool. The method further comprises allowing S4the 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 combination4, away from the work material, is enabled or assisted S5by a spring action of the second damping element32″. Further, the return movement of the movable impact head and tool combination4, is dampened S6by the first dampening element32′.

Preferably, the drive unit2, in this example the plunger, moves, upon the impact with the impact head, away from the work material. Thus, the drive unit2may be arranged to move, upon the impact with the impact head, away from the work material. The drive unit2may be arranged to bounce, upon the impact with the impact head. The movement of the drive unit2, 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 unit2, 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.

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.

FIG.5shows 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 toFIGS.1and2. The apparatus comprises a frame30. The frame is supported by a plurality of support devices110. An anvil106is fixed to the frame. In this embodiment, the anvil106is fixed at the top of the frame30.

A tool, herein referred to as a fixed tool5, is mounted to the anvil. The fixed tool5is mounted to a lower side of the anvil106. A movable impact head and tool combination4, described closer below, is located below the fixed tool5. The impact head and tool combination4and the fixed tool5present complementary surfaces facing each other. A workpiece W is removably mounted to the fixed tool5. The workpiece W may be mounted to the fixed tool5in 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.

In the embodiment shown inFIG.5, a drive assembly comprising a cylinder housing102is mounted to the frame30. Further, the drive assembly comprises a plunger101that is arranged in the cylinder housing102. The plunger101is 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 plunger101is arranged to move towards and away from the fixed tool5, as described closer below.

In this embodiment, the impact head and tool combination4is in contact with the plunger101as the plunger is accelerated by means of a hydraulic system6. Therefore, there is no impact between the plunger101and the impact head and tool combination4. Therefore, what is here referred to as an impact head and tool combination4may be provided with an “impact head” forming merely a support for a tool of the impact head and tool combination4. Before providing kinetic energy to the tool by moving or accelerating the plunger101, 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.

The plunger101is arranged to accelerate the impact head and tool combination4towards the fixed tool. The plunger101is arranged to be driven by the hydraulic system6. Before the impact head and tool combination4strikes the work material W, the plunger101decelerated so that the impact head and tool combination4continues by inertia towards the work material W.

When the impact head and tool combination4has struck the work material W, the impact head and tool combination4moves away from the work material W, and towards the plunger101by gravity. To brake the return movement of the movable impact head and tool combination4as it approaches the plunger101, a damping arrangement32is provided. In this example, the damping arrangement comprises a damper mounted to the plunger101. 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 combination4. In further embodiments, the damping arrangement may comprise a damper mounted to the frame30. 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 combination4at the end of its return movement. Thereby, the movable impact head and tool combination4may be brought back to rest on the plunger in a controlled manner.

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.