Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D51/00—Driving, starting, or stopping arrangements; Automatic stop motions
  • D03D51/02—General arrangements of driving mechanism

Definitions

• the invention relates to a method of reducing vibrations and forces in shed and other mechanisms of weaving looms comprising a cam mechanism.
• the chief cause of the lack of uniformity of the main shaft rotation of weaving looms is the batten mechanism, and in needle machines the pick mechanism as well.
• the reduced inertia moments of these mechanisms as a function of the angular position of the main shaft are not constant.
• the batten mechanism usually has the highest reduced inertia moment of all the machine mechanisms. Due to this, a part of the kinetic energy flows from the main shaft to the batten mechanism and back during one cycle of the loom. As a rule, the energy of the main shaft reaches its maximum at the beat-up and at the rear dead center, while it, and consequently its speed of rotation, are at their minimum in the interval of the maximum speed of the batten.
• the principle of the invention consists in such a modification of the stroke interdependence of the shed mechanism or of another mechanism of the weaving loom resulting from the shape of the drive cam or double cam of the mechanism which eliminates the non-uniformity of the rotation of the drive shaft of the mechanism and thus makes the mechanism move in the manner proposed for the constant rotation speed of the drive shaft of the mechanism.
• the advantage of the invention consists in substantial reduction of vibrations and forces of the shed mechanism or of another mechanism of the weaving loom, thus improving the function of the mechanism, increasing its service life, and reducing the noise level.
• the following limitations should be taken into consideration: a) the elimination of the influence of the non-uniform rotation is operative only in a given though relatively broad range of the operation speed, b) the angular position of the drive cam or double cam of the shed mechanism or of another mechanism of the weaving loom must be correctly set in relation to the main shaft of the machine.
• the calculation of the stroke interdependence of the shed mechanism or another mechanism of the weaving loom can be carried out with taking into account the influence factors of various relevance acting on the weaving loom and with the use of the calculation apparatus of various complexity available in the mechanism dynamics.
• the following examples are limited to simple solution methods only which do not take into consideration some influence factors but still achieve substantial advantages aimed at by the invention.
• the mechanism when using the stroke function z , moves at a non-constant main shaft angular velocity ⁇ in the same manner as the original mechanism with the stroke function y at a constant main shaft angular velocity ⁇ s .
• the function z is set generally as a function of time.
• the equation (11) permits a very simple approximative calculation of the function z provided that the fluctuations in the main shaft angular velocity ⁇ are not too great. Then can be set dy d ⁇ ⁇ dy d ⁇ and the equation (11) gives the required function z ( ⁇ ) ⁇ ⁇ s ⁇ dy d ⁇ 1 ⁇ ( ⁇ ) d ⁇ .
• the method of the invention can be used also for the calculation of the modified stroke function of the batten mechanism.
• the following example of embodiment gives a simple calculation of the modified stroke function.
• the batten mechanism when using the stroke function ⁇ , moves at a non-constant main shaft angular velocity ⁇ in the same manner as the original mechanism with the stroke function ⁇ at a constant main shaft angular velocity ⁇ s .
• the calculation is based on the following assumptions:
• I h stands for the aggregate reduced inertia moment of the main shaft involving the drive system with the electric motor and average reduced moments of all the mechanisms except the batten one
• ⁇ is the main shaft angular velocity, not known beforehand
• I b is the inertia moment of the batten
• ⁇ ⁇ is the angular velocity of the batten (the point designating the derivative on time)
• I s is the constant average reduced inertia moment of the whole weaving loom at the average main shaft angular velocity ⁇ s (the expression on the right side of Equation (15) denoting the aggregate kinetic energy of the weaving loom which is under the mentioned assumptions constant).
• the further procedure is the same as in Example A but for the fact that the modified function ⁇ ( ⁇ ) is searched for the given function ⁇ ( ⁇ ) .
• the method of reducing vibrations and forces in shed mechanisms and other mechanisms of weaving looms can be used on all cam-driven types of weaving looms. Its application is particularly important in wide looms with dwell batten mechanisms where the natural frequency of the shed mechanism oscillations is relatively low whereas the exciting frequency due to the non-uniform main shaft rotation is relatively high and near the resonance frequency of the shed mechanism.
• the method according to the invention cn be used in other machine types as well where cam mechanisms are used and the main shaft angular velocity fluctuations take place.
• cam mechanisms are used and the main shaft angular velocity fluctuations take place.
• gear mechanism of internal combustion motors As an example can be named the gear mechanism of internal combustion motors.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Looms (AREA)
• Gears, Cams (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=5464024

Family Applications (1)

Country Status (2)

Families Citing this family (1)

Family Cites Families (6)

• 1999
  • 1999-05-31 CZ CZ19991909A patent/CZ9901909A3/cs unknown
• 2000
  • 2000-05-24 EP EP00111144A patent/EP1061284A3/de not_active Withdrawn

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