Juki Corporation

Kabushiki Kaisha Toshiba

Nec Electronics Corporation

Yasushi Baba

Shiro Satoma

Shuji Fujita

Hitoshi Itoh

In a method of adjusting a process control device wherein a closed loop system comprising a control subject and external compensator is approximated by a transfer function expressed by the time constant of a first-order delay filter and a dead time, adjustment is effected by displaying the step response of the closed loop system as a first response, displaying the step response of a model transfer function of the closed loop system as a second response in superimposed fashion with the first response, adjusting the respective parameters so that the difference of the first response and the second response is within a prescribed evaluation standard range, and performing prescribed conversion and setting of this model parameter as a control parameter of the controller, so that the response of the process control device is within a prescribed evaluation standard range.

Method of adjusting a process control device, adjustment tool therefor and process control device thereof

A small-scale timer assembly includes a PWM signal generator including a selector for selecting one of a plurality of clock sources, a timer for counting based on the selected clock source to deliver an overflow signal, a comparator for comparing the count in the timer against a setting to deliver a coincidence signal, and a signal processor for generating a PWM signal based on the overflow signal and the coincidence signal, and a count controller for counting the number of overflow signals to allow the selector to select another of the clock sources. The PWM signal is used for generating a sinusoidal signal.

Timer assembly for generating a PWM signal

A safety device for an overlock sewing machine comprises: a way of selecting having an operating part located at which a loop cover covers, for selectively setting the operating part to a first mode set-up position to set up a first stitching mode using an auxiliary cloth table or to a second mode set-up position to set up the second stitching mode using a cloth waste cover, a way of contacting having an engaging part that may engage the operating part of the a way of selecting, the way of contacting being movably supported by the looper cover such that the engaging part is positioned in front of the second mode set-up position when the auxiliary cloth table is set to the looper cover, and that the engaging part is positioned in front of the first mode set-up position when the cloth waste cover is set to the looper cover, in the case that the engaging part comes in contact with the operating part, the way of contacting hindering the looper cover from turning toward a stand-up position thereof, and a way of operating coupled with the way of contacting so as to move the way of contacting when one of the auxiliary cloth table and the cloth waste cover is set to the looper cover.

Safety device for an overlock sewing machine

A thread spreading apparatus for use in an overlock sewing machine capable of performing over-edge chain stitching and other stitching. The thread spreading apparatus uses a lower looper for over-edge chain stitching to allow a needle to surely drop into a triangle defined by a needle thread, a looper thread and the lower looper, thereby enabling multi-thread chain stitching and covering chain stitching to be performed without fail. The apparatus includes a thread spreading hook having hook portions with different heights for retaining needle threads and a projection formed on one of the hook portions. During stitching other than over-edge chain stitching, the hook portions of the thread spreading hook retain the needle threads when two needles drop, thereby allowing each needle to drop into a triangle defined by the looper thread, the lower looper and the corresponding needle thread. During over-edge chain stitching, the hook portions lie rearwardly of an idle chain stitch forming bore provided in a needle plate.

Thread spreading apparatus for use in overlock sewing machine

There is provided a needle attachment position indicator device for use in a sewing machine of a type comprising a stitch pattern forming mechanism provided in a machine frame for permitting selection of one stitch pattern from a plurality of different stitch patterns, an actuator member disposed in the machine frame for permitting selection of the stitch pattern, an actuation mechanism disposed in the machine frame for setting the stitch pattern forming mechanism at selected stitch pattern in response to the selective actuation of the actuator member, and needle holding means having a plurality of needle attachment positions. The device includes an indicator member capable of indicating needle attachment position corresponding to the selected stitch pattern, in response to the selective actuation of the actuator member.

Needle attachment position indicator device

An overlock sewing machine is provided with means for driving a lower looper according to a plurality of different oscillational movements independently of each other, a clutch mechanism for changing the aforementioned movements from one to the other mode, a back and forth drive mechanism for moving a lower looper back and forth, a mechanism for transmitting movement of the back and forth drive mechanism to a lower looper and releasing transmission of the movement therefrom, a lower looper oscillating means for oscillatively moving a lower looper, a mechanism for releasing oscillational movement of the upper looper therefrom, and a motion change-over device for interchanging operation between the clutch mechanism, the transmission and release means, and oscillational movement release means. The arrangement permits conversion of various stitch formations in a sewing machine to take place in a simple manner without requiring complicated adjustment.

Growing community of inventors

Tokyo, Japan

Yasushi Baba