Shaft drive for a power loom

Abstract

The heddle shaft (1) according to the invention combines a traditional heddle machine (2) with an eccentric toothed gearing to purposely allow the heddle shaft (1) to dwell for longer periods of time in the upper and lower reversing region and to reduce any accelerations that occur. This permits an increase in the weaving speed and / or the weaving widths. For a particularly advantageous embodiment, a coupling device is additionally provided, which gives the heddle shaft (1) a pendulum movement with a stroke ranging from a few millimeters to centimeters during the idle phases, meaning when no sheds are formed. As a result of the pendulum movement of the heddle shaft (1) in the upper or lower reversing region, the acceleration loads on the heddle shaft (1) can be further reduced.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the priority of German Patent Application No. 10 2005 059 911.7, filed on Dec. 15, 2005, the subject matter of which, in its entirety, is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] The invention relates to a shaft drive for a power loom, provided with one or several heddle shafts. [0003] Power looms are generally provided with several heddle shafts in the form of rectangular, vertically positioned frames. These heddle shafts accommodate heddles for guiding the on the whole horizontally extending warp threads, so as to move them vertically up and down for the shed forming. In the process, the heddle shafts normally execute an up and down swinging movement, generated by a so-called shaft drive and / or a heddle machine. The shaft drive is a gear for converting the rotational driving movement to a back and forth movement, wherein the shaft essentially follows a sinusoidal function. [0004] Star...

AI Technical Summary

Benefits of technology

The invention is a shaft drive for a heddle shaft that uses eccentric toothed gearing to achieve a modulated rotational speed. The gearing has a non-constant transmission ratio that depends on the angular position of the drive shaft. This results in a non-uniform movement of the shaft, but with a soft torque increase and minimum rotational speed during the engagement and disengagement of the coupling device. The shaft drive can be used for both continuously operating heddle shafts and heddle machines that must be started and stopped. The coupling device allows for a pendulum movement and synchronous phases for engaging or disengaging. The eccentric toothed gearing can be a standard shaft drive or a supplementary gear, and the whole number ratio of the teeth on the toothed gears is preferably 1:1. The toothed gears can be slightly counterbalanced to increase or reduce the transmission ratio twice during one rotation of the input shaft. This allows for more time for inserting the weft yarn into the shed.

Problems solved by technology

A modulation gear of this type is expensive.

In addition, it has turned out that the cams and the modulation gears on the whole require a relatively large structural volume.

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