Cutting – Cutting motion of tool has component in direction of moving... – With means to initiate intermittent tool action
Reexamination Certificate
2000-03-08
2001-10-02
Rada, Rinaldi I. (Department: 3724)
Cutting
Cutting motion of tool has component in direction of moving...
With means to initiate intermittent tool action
C083S295000, C083S296000, C083S299000, C083S304000, C083S344000, C083S563000, C083S698610
Reexamination Certificate
active
06295909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method of shearing metal strip and apparatus therefor. In particular the invention relates to the shearing of continuous strip, at the end of its production, into finite lengths which are coiled onto a spool.
2. Description of Related Art
In many strip production facilities the shearing has to take place whilst the strip is moving at high speed, and modern strip production requires the strip to be moving at higher and higher speeds to ever greater efficiencies in production costs. Typically in known systems, a rotary shear is used to cut metal strip which is moving. Such a conventional rotary shear is shown consists of two rotating drums each of which has a cutting blade. The two drums rotate in opposite directions, and are usually geared together. Separate guide means are usually provided to guide the strip onto a coil at the end of a rolling mill line and to transfer the strip to a second coil when a first coil is complete, whilst at the same time permitting the continuous production of the strip at an uninterrupted rate.
The strip passes between the two drums. When the strip is to be cut, the two drums are accelerated from rest until the peripheral speed of the blades is equal to the strip speed. The peripheral speed of the blades needs to be closely matched to the speed of the snip, otherwise the shear will cause a tension snatch in the strip which could damage the strip, the shear or other equipment in the line. After the blades have cut the strip, the drums are then decelerated back to rest.
With such a conventional rotary shear, since the drums cannot be allowed to rotate through the cutting position more than once, the maximum speed at which the strip can be cut is limited by the power required to accelerate and decelerate the drums within less than one revolution. To accelerate the drums to a higher speed requires more power, which in turn requires a bigger drive motor, which in turn increases the total inertia of the system and thus demands even more power.
It is possible for rotary shears of this type to have more than one set of blades. In these cases the problem of accelerating and decelerating the drums is even more pronounced because a smaller fraction of a revolution,is available for acceleration and deceleration.
Mannesmann AG, EP 0 771 603 A1 shows a drum with a moveable cutter blade.
FIG. 1
shows a simple wedge-type actuator for position control, using hydraulic control.
FIGS. 4 and 5
show a multi-step actuator, requiring less actuator movement and giving semi-stable full-in and full-out cutter positions. US Steel, U.S. Pat. No. 3,057,239 shows a cutter with a cylinder
2
having a fixed blade
30
and cylinder
4
a retractable blade
58
, which is controlled (
FIG. 3
) by an axially movable element
46
having pins
52
which enrage in sloping slots
62
in the blade
58
.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an improved cutter arrangement.
According to one aspect, the present invention provides metal strip cutting apparatus comprising two rotatable drums having respective cutting blades and arranged side-by-side so that the metal strip may pass between them, one of the blades being movable, under the control of an axial actuator rod in the drum, between a retracted position in which the strip passes freely between the drums as the drums rotate and an extended position in which the blades cut the strip, characterized in that the actuator rod is coupled to the blade by rollers.
The invention thus provides an arrangement whereby low-friction engagement is provided between the actuator rod and the blade. Preferably the rollers are in pairs on opposite sides of the actuator rod, giving a positive positioning of the blade. This, together with suitable profiling of the sides of the actuator rod, allows the blades to be given smooth acceleration and deceleration, reducing the size of the operating forces required. Preferably also unidirectional movement of the actuator produces extension then retraction of the blade. This has the advantage that the extended position of the blades can be arranged to be on a flat or nearly flat position of the actuator, so that the position of the blade is determined independent of any slight axial error in the positioning of the actuator.
According to another aspect the present invention provides a method of cutting metal strip using the apparatus just defined, characterized in that the drums are rotated at a speed matching the speed of the metal strip and, at the desired time, the movable blade is extended in less than one revolution of the drums, cuts the strip, and is retracted in less than the next revolution of the drums.
REFERENCES:
patent: 2245442 (1941-06-01), Morgan
patent: 2274452 (1942-02-01), MacFarren
patent: 3057239 (1962-10-01), Teplitz
patent: 3628410 (1971-12-01), Shields
patent: 4065992 (1978-01-01), Peters et al.
patent: 4103577 (1978-08-01), Jackson et al.
patent: 4141266 (1979-02-01), Hara et al.
patent: 4485710 (1984-12-01), Schlisio et al.
patent: 4497229 (1985-02-01), Carrington et al.
patent: 4656905 (1987-04-01), Ginzburg et al.
patent: 4685318 (1987-08-01), Ueda et al.
patent: 4984491 (1991-01-01), Bragaglia
patent: 5464166 (1995-11-01), Kirkpatrick, III et al.
patent: 5904086 (1999-05-01), Figge et al.
patent: 5950516 (1999-09-01), Stab
patent: 1 218 794 (1968-10-01), None
patent: 0 771 603 A1 (1997-05-01), None
Berry John
Cooper Brian
Schofield Simon
Goodman Charles
Kvaerner Technology & Research Limited
Oliff & Berridg,e PLC
Rada Rinaldi I.
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