Method and device for regulating the sliver in a card
AssigneeMaschinenfabrik Rieter AG
InventorsJurg Faas, Christian Muller
Life of this patent
Estimating the term…
Abstract
A method and device for controlling a card with a feed roll, a doffer, and a control wherein the feed roll is controlled relative to the doffer in such a way that during running up or braking transitory (transient) phenomenon in the formation of a sliver are at least partially compensated for by controlling the relative speeds of the feed roll and doffer during the running up or braking periods.
Claims13
A method for controlling a card having a doffer and feed roll with respective drives so as to minimize undesired thick or thin spots produced in a sliver during transitory periods of operational speed changes of the card wherein the feed roll slows down or speeds up causing a corresponding decrease or increase in the rate of fiber infeed to the card, said method comprising:
- controlling the drives of the doffer and feed rolls during the transitory periods to generate a varying draft between the doffer roll and the feed roll during the transitory period
- such that during an acceleration transitory period wherein the feed roll increases in speed, the speed relationship of the doffer roll and feed roll is controlled so that the difference between the speeds of the doffer roll and feed roll initially decreases and subsequently increases until the doffer roll and feed roll are at operational speed;
- and
- such that during a braking transitory period wherein the feed roll decreases in speed, the speed relationship of the doffer roll and the feed roll is controlled so that the difference between the speeds of the doffer roll and feed roll initially increases and subsequently decreases.
A card machine, comprising:
- a main cylinder, and a feed roll disposed for delivering a fiber material to said main cylinder:
- a doffer disposed for receiving fiber material from said main cylinder:
- controllable drive devices operably connected with said feed roll and said doffer;
- a control system configured with said drive devices, said control system configured to drive said doffer and feed roll during transient non-operational speed phases of said card such that during an acceleration transitory period wherein said feed roll increases in speed, the difference between the speeds of said doffer roll and feed roll initially decreases and subsequently increases until said doffer roll and feed roll are at operational speed;
- and such that during a braking transitory period wherein said feed roll decreases in speed, a corresponding decrease in speed of said doffer roll is controlled so that the difference between the speeds of said doffer roll and feed roll initially increases and subsequently decreases.
A card machine comprising a feed roll and a doffer, and a control system operably connected to controllable drives of said feed roll and said doffer for controlling relative speed changes between said feed roll and said doffer during transient running up or braking phases of said card machine so that undesired thick or thin spots in a fiber sliver processed by said card machine are minimized during said transient phases, said control system configured such that during said running up transitory period wherein said feed roll increases in speed, said doffer and feed rolls are controlled so that the difference between the speeds of said doffer roll and feed roll initially decreases and subsequently increases until said doffer roll and feed roll are at operational speed;
- and
- such that during said braking transitory period wherein said feed roll decreases in speed, said doffer and feed rolls are controlled so that the difference between the speeds of said doffer roll and feed roll initially increases and subsequently decreases.
Dependencies are inferred from the claim text.