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
  • B21D45/00—Ejecting or stripping-off devices arranged in machines or tools dealt with in this subclass
  • B21D45/06—Stripping-off devices
  • B21D45/065—Stripping-off devices for deep-drawn cans, e.g. using stripping fingers
• • 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
  • B21D45/00—Ejecting or stripping-off devices arranged in machines or tools dealt with in this subclass
  • B21D45/06—Stripping-off devices

Definitions

• the invention relates to a device for stripping a can-like product, which has been 5 formed around a punch, off the said punch in the axial direction, such as for stripping a wall-ironed can body from the punch, comprising a support frame containing stripping fingers suspended therein which, at a relative axial movement of punch and support frame, are suitable for interacting with the product at the circumference of the punch in such a manner that the product comes into contact with the stripping fingers, with the 0 result that, at a further relative movement, the punch and the product around the punch are pushed or pulled apart by a certain stripping force, a compensation means being incorporated between the stripping fingers and the support frame, which means that, in case of axial displacement in the direction of the support frame, of a stripping finger with which the product has come into contact, effects an opposite displacement of one 5 or more other stripping fingers.
• the invention also relates to a method for stripping a can-like product which has been formed around a punch off the said punch in the axial direction
• the stripper device described in this Japanese abstract is intended to compensate for an inclined position of the punch with respect to the stripper device, which has the same effect as a slightly corrugated edge on the can-like product.
• the known device partially solves the problem described, it remains the case that the stripping finger which makes first contact with the edge of the can-like product exerts the greatest stripping force on the edge during stripping. Therefore, the risk of "roll-back" remains present. Also, if the edges are more strongly corrugated, the known device will not engage on the entire edge, with the result that the stripping force is not well distributed.
• One object of the invention is to remedy or further reduce the extent of the problem outlined. Another object of the invention is to ensure that the total stripping force exerted on the can-like product is optimally distributed over the edge of the canlike product.
• the compensation means comprises a closed, fluid-filled system
• the stripping fingers interacting with the system during operation.
• the use of a fluid-filled system with which the stripping fingers interact ensures that, when the edge of the can-like product comes into contact with the first stripping finger, the fluid-filled system is compressed by this stripping finger without a significant force being required to achieve this.
• the fluid is displaced, and since the system is closed, the other stripping fingers, on which no load is being imposed, are lifted slightly. The same applies to the second and subsequent stripping fingers, until all the stripping fingers bear against the edge of the can-like product. Only then are all the stripping fingers subjected to the entire stripping force for stripping the can-like product off the punch.
• the fluid is preferably a hydraulic liquid. A hydraulic liquid is virtually incompressible, so that the system as a whole cannot be compressed.
• the hydraulic system comprises a bellows in which the hydraulic liquid is accommodated.
• a bellows is a relatively simple structural element which forms an eminently useable compensation means for the stripping fingers.
• the support frame, the stripping fingers and the compensation means are constructed in such a manner that, during use, the total axial displacement of all the stripping fingers which move in the direction of the compensation means is substantially equal to the total axial displacement of all the stripping fingers which move in the opposite direction.
• the bellows has to be held in such a manner that compression by a certain distance caused by one stripping finger results in an expansion of the bellows at the location of one or more further stripping fingers, the total displacement of the further stripping fingers being equal to the displacement of the stripping finger causing compression. Therefore, the bellows may only expand at locations where it is in contact with the stripping fingers.
• the invention also relates to a method for stripping a can-like product which has been formed around a punch off the said punch in the axial direction, in which use is made of the device according to the invention as described above, the punch, with the product formed around it, and the stripping fingers being moved towards one another in the axial direction and, when the product comes into contact with the stripping fingers, the compensation means being deformed in such a manner that the stripping fingers strip the product off the punch using a substantially equal stripping force when the punch is moved further with respect to the stripping fingers.
• the invention also relates to the can-like products which are stripped using the above mentioned method.
• the method according to the invention allows the can-like products to be very thin-walled without their edge being deformed by roll-back.
• Fig. 1 shows a front view of a stripping tool and a cross section through the stripping tool, in the left-hand half according to the invention and in the right-hand half for a known stripping tool,
• Fig. 2 shows a punched-out can-like product in three stages of interaction with the stripping fingers, for a situation in which the method and the stripping tool according to the invention are being used, and
• Fig. 3 shows a punched-out can-like product in three stages of interaction with the stripping fingers, for a situation in which the known working method is being used.
• the punch (not shown), with the can-like product (not shown) on it is moving upwards through the stripping tool 1 and subsequently reverses the relative direction of movement, with the result that the edge of the can-like product approaches the stripping fingers 4 which are held together in the radial direction by a rubber or plastic O-ring 5.
• this stripping finger is pressed against the solid rubber or plastic O-ring 5, with the result that the stripping finger in question, at a slight displacement, is already exerting a significant counteracting force on the product.
• the stripping finger 4 of the stripping tool 1 when such a protruding part of the edge of the product comes into contact with the stripping finger 4 of the stripping tool 1 according to the invention, this stripping finger 4 is pushed into the bellows 3, with the result that the other stripping fingers 4 are moved towards the edge of the product without any associated build-up of a counteracting force which is transmitted to the edge of the product by only one or a few stripping fingers 4.
• the bellows 3 is filled, for example, with medium 2, for example a hydraulic liquid or a mixture of a liquid and a gas.

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19768591

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (3)

• 1999
  • 1999-02-02 NL NL1011203A patent/NL1011203C2/nl not_active IP Right Cessation
• 2000
  • 2000-01-28 WO PCT/NL2000/000061 patent/WO2000045975A1/en active Application Filing
  • 2000-01-28 AU AU24681/00A patent/AU2468100A/en not_active Abandoned

Patent Citations (3)

Non-Patent Citations (1)

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