Advancing material of indeterminate length – Plural material-moving means – Continuous feed from serial sequentially operated feeders
Patent
1996-04-16
1999-06-08
Marmor, Charles A.
Advancing material of indeterminate length
Plural material-moving means
Continuous feed from serial sequentially operated feeders
226149, 744248B, B65H 2024, B65H 2306, F16H 118
Patent
active
059098350
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a gripper feeder for metal strip.
DESCRIPTION OF THE PRIOR ART
Metal strip feeders are known for presses and machines in general in which the strip is subjected to particular operations as required.
A known type of feeder of pneumatic operation uses two clamps acting transversely on the strip to be conveyed. One of these clamps is fixed, while the other is driven with reciprocating movement in a direction parallel to the longitudinal axis of the strip. In operation, the two clamps are operated alternately in a synchronized manner in the sense that when the fixed clamp is open the mobile clamp is closed onto the strip to advance it, whereas on termination of the advancement stroke of the mobile clamp the fixed clamp is closed and, after being opened, the mobile clamp is returned backwards to grip the metal strip further upstream and then advance it through a further distance when the fixed clamp is reopened.
A drawback of this known feeder is that it is non-continuous and does not enable high operating speeds to be achieved.
A further drawback is that it is extremely rigid, in the sense that it requires laborious manual action each time the advancement pitch of the metal strip is to be modified.
A further drawback is that as it moves the metal strip by thrusting, it cannot be used for very thin strip.
A further drawback is that it occupies the entire surface of the strip to be conveyed and does not allow it to be operated upon in that part engaged by the feeder.
A further drawback is that it has a transverse dimension greater than the width of the strip, and for certain strip widths this dimension becomes excessive.
A further drawback is that it cannot produce an advancement pitch greater than certain length.
A roller feeder is also known comprising at least one pair of counter-rotating rollers between which the metal strip to be advanced is interposed. It substantially overcomes the drawbacks of known pneumatic feeders, and in particular is of continuous programmable operation. However it has other drawbacks, and in particular: subjected to other operations during the gripping; horizontal plane or is inserted incorrectly into the feeder, transverse stresses of a progressively increasing extent arise and can be eliminated only by periodically slackening the grip between the rollers; arise because of the inevitable slippage between the rollers and the strip; if however it is controlled by acting on the strip itself these errors are not present, but the feeder then has a low advancement speed because of the need to correct errors deriving from inevitable slippage.
Mechanical feeders with grippers controlled by the power machine positioned downstream of them are also known. In this case the grippers are driven with reciprocating movement and are reliable and fast. However they are extremely rigid in their performance and involve slow and difficult adjustment, which can be effected only by specialized personnel. EP-A-4874456 describes a method and device for advancing a band, in which the stepwise transport of the band is performed by two grippers which are moved backwards and forward synchronously, each in their longitudinal direction by a common drive.
BRIEF DESCRIPTION OF THE INVENTION
The object of the invention is to provide a feeder: enables it to be subjected to operations during its conveying;
All these objects and further ones are attained according to the invention through a gripper feeder for metal strip comprising on a base: advanced; said strip and in the opposite direction; and moves in the direction of advancement of the strip is activated, whereas that which moves in the opposite direction is deactivated, said members for moving said grippers consisting of a rod engaged with a threaded bush provided on the grippers, and rotated by a single electric motor powered alternately in the two directions of rotation characterized in that said rod has two portions threaded in opposite directions.
BRIEF DESCRIPTION OF THE DRAWINGS
Two preferred emb
REFERENCES:
patent: 3583268 (1971-06-01), Scribner
patent: 4513899 (1985-04-01), Ledgerwood
patent: 4558809 (1985-12-01), Schoen
patent: 4577483 (1986-03-01), Rehag et al.
patent: 4577791 (1986-03-01), Leinhaas
patent: 4580710 (1986-04-01), Ledgerwood
patent: 5505360 (1996-04-01), Giusto
Dalcos S.R.L.
Kaness Matthew A.
Marmor Charles A.
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