US 7,124,697 B2 · Apparatus for monitoring and controlling thread tensioning force in a sewing machine

Abstract

A thread tensioning device or apparatus for a sewing machine enables accurate, repeatable measurement and monitoring of the compression forces applied to the thread tensioning discs thereof. The apparatus further includes a visual display or output corresponding to the actual amount of compressive force being applied. The device further includes a comparator, which compares the electrical signal to a predetermined reference value to control or regulate the normal operation of the sewing machine.

Drawings

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Drawings

Claims8

Dependent claims

A thread tensioning apparatus for adjusting and monitoring the tension in a thread passing through a sewing machine during a stitching operation, comprising:

a pair of clamping members movably mounted in juxtaposition with one another, the clamping members being movable towards one another and into clamping relation with the thread passing therebetween during the stitching operation,
an electromechanical compression load cell disposed in contacting relation against one of said clamping members, said load cell being separate and apart from said clamping members and operable under compression to generate an output signal representative of the compressive load placed on said load cell and the tension in said thread,
a comparator for receiving and comparing the output signal to a predetermined value representative of a desired thread tension and providing a command signal to indicate that the clamping pressure against the thread and thus the tension in the thread is not in conformance with the desired tension,
a force member for biasing the other of said clamping members towards said one clamping member and against said thread, said thread being squeezed between said clamping members and said one clamping member being forced against said load cell wherein to place a compressive force on said load cell,
a manually operated adjustment knob, said knob being abutted against said force member and mounted for movement towards and away from said load cell for increasing or decreasing the compressive force applied by said force member against said load cell, and
wherein when the comparator generates a command signal that the tension in the thread is not in conformance with the desired tension, the adjustment knob is moved towards or away from the load cell to increase or decrease the compressive force of the clamping members on the thread to adjust the tension in the thread as needed.

3 more elements

A thread tension adjusting apparatus for adjusting and monitoring the tension of a supplied thread in a sewing machine, comprising:

a partially threaded mounting shaft, which projects from the sewing machine,
a spacer fixedly connected to the distal end of said shaft,
a pair of thread clamping members slidably disposed in juxtaposed relation on said shaft and interposed between said spacer and said sewing machine, and
a force member adapted to undergo axial reciprocating movement relative to the spacer and said sewing machine with axial reciprocating movement moving the force member into and away from engagement with the thread clamping members and placing a thread passing between the clamping members under increased or decreased compression, wherein
said force member comprises a pneumatically controlled actuator, said actuator including an actuator body connectible to a compressed air source, and
said spacer comprises an actuator rod adapted to undergo axial reciprocating movement relative to the actuator body with axial reciprocating movement of the actuator rod moving the actuator body towards and away from the thread clamping members and the clamping members towards and away from engagement with the sewing machine, the reciprocating movement placing the clamping members under increased or decreased compression, respectively, to increase or decrease the compressive grip of the clamping members on the thread and the tension in the thread passing between the thread clamping members.

3 more elements

Dependencies are inferred from the claim text.

Description3,791 words

Summary1,543 words

#1. Field of the Invention

#The following invention relates to sewing machines, and more particularly, to automatic apparatus for monitoring and controlling thread tensioning force in a sewing machine.

#2. Description of Prior Art

Brief description of the drawings5 figures

#These and other objects, advantages and features of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, which illustrate specific embodiments of the invention. In the drawings:

#FIG. 1 is a perspective view of a sewing machine arrangement having a display unit associated therewith;

#FIG. 2 is an exploded view of a thread tensioning apparatus according to the present invention used in the sewing machine of FIG. 1;

Detailed description2,124 words

#Referring to FIG. 1, a sewing system according to this invention is generally denoted by the number 10 and includes a sewing machine 12 operably connected to a display monitor 14 to provide the user with a readout of the tension in the sewing thread 16 during operation of the sewing needle 18. Additionally, the sewing machine assembly 10 includes an electronic control assembly (not shown) electrically connecting the output of a load cell (to be described herein below) to the monitor 14. It is to be noted that the integration of the display unit 14 for visually displaying the tension is ordinarily not associated with a conventional industrial sewing machine. However, to facilitate the full use and spectrum of the present invention optimally such a display unit is associated herewith.

#The sewing machine 12 includes a shaped body or housing 20, which encloses an array of gears, cams, cranks and belts, and an electric motor to drive the machine parts. The exact configurations of these elements differs from machine to machine and are not described herein as being understood by one skilled in the sewing machine art. In general, the electric motor is connected to a drive wheel by way of a drive belt. The drive wheel rotates a drive shaft, which is in turn interconnected with several mechanical elements. The end of the drive shaft turns a crank, which pulls a needle bar, and thus the needle 18 up and down.

#Sewing thread runs from a spool or source, through a thread tension disc assembly, and to the needle. By manipulating the disc assembly, the operator can tighten the thread feeding into the needle.

Facts

Application

10/625,273Filed 23 Jul 2003 · us provisional application

Priority

2 Aug 2002

Published

US 2004/0103834 A13 Jun 2004

Granted

24 Oct 2006

Term ended

25 Oct 2023

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 94 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification5 codes

D05B 47/04
Needle-thread tensioning devices; Applications of tensometers: automatically-controlled tensioning devices
D05B 47/06
Needle-thread tensioning devices; Applications of tensometers: applications of tensometers
D05D 2205/18
Display arrangements: screens
D05B
Sewing

Apparatus for monitoring and controlling thread tensioning force in a sewing machine

Life of this patent

Apparatus for monitoring and controlling thread tensioning force in a sewing machine

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims8

Description3,791 words

Drawings

Classification5 codes

Life of this patent

Description3,791 words