Movement Detector and Sewing System

This application claims priority from Japanese Patent Application No. 2024-048900 filed on Mar. 26, 2024. The entire content of the priority application is incorporated herein by reference.

A fabric movement detector detects movement of a fabric and adjusts a rotation speed of a motor of a sewing machine in accordance with a detection result.

A fabric movement detector includes a main body and a presser support portion. The presser support portion is attached and detached at a lower portion of an outer periphery of the main body. The presser support portion is configured to contact a fabric disposed below the main body from above. The presser support portion is provided in a plurality of types having shapes corresponding to sewing work and usability of the sewing machine, and is replaceable with respect to the main body.

In the above-mentioned fabric movement detector, each presser support portion is detached downward from the main body and is pushed up from below to be attached to the main body. A thick fabric to be sewn may be disposed below the main body. In this case, the gap between the main body and the thick fabric is small, and the fabric disposed below the main body becomes an obstacle when a user attaches and detaches the presser support portion to and from the main body. This makes it difficult for the user to attach and detach the presser support portion to and from the main body.

In view of the foregoing, an example of an object of this disclosure is to provide a movement detector and a sewing system that contribute to easy attachment and detachment of a presser foot to and from a housing.

According to a first aspect of the present disclosure, this specification discloses a movement detector attachable to a presser bar of a sewing machine. The movement detector includes a sensor and a housing. The sensor is configured to emit light toward a sewing workpiece and to detect the light reflected from the sewing workpiece to detect a movement amount of the sewing workpiece. Thus, the sensor detects the movement amount of the sewing workpiece. The housing accommodates the sensor. The housing includes a wall surface spaced from the sensor in a detachment direction. The detachment direction is perpendicular to an emission direction in which the sensor emits the light. The wall surface is formed with an insertion opening for inserting a presser foot. Thus, the pressor foot is inserted into the housing through the insertion opening.

According to the movement detector of the first aspect, the presser foot is attached to and detached from the housing through the insertion opening formed in the detachment direction of the housing. Thus, the presser foot is easily attached to and detached from the housing, compared with a case where the presser foot is attached to and detached from the housing by moving in the emission direction.

According to a second aspect of the present disclosure, this specification discloses a movement detector attachable to a presser bar of a sewing machine. The movement detector includes a sensor, a housing, and a presser foot including an insertion plate, a presser plate, and a connection plate. The insertion plate is inserted into the housing through the insertion opening. The insertion plate is locked in the housing. The presser plate is located at a position toward the emission direction and the detachment direction from the insertion plate. The presser plate extends in a slide direction including both the detachment direction and an attachment direction opposite the detachment direction. The connection plate connects the insertion plate and the presser plate. The connection plate extends in the emission direction from the insertion plate. The connection plate is formed with a connection plate opening extending in the emission direction from the insertion plate.

A member other than the movement detector, such as a needle bar of the sewing machine, may be provided in the detachment direction of the housing. In the movement detector in which the insertion plate is detached through the insertion opening of the housing in the detachment direction or the insertion plate is attached through the insertion opening from the detachment direction, the presser foot may contact (interfere with) the other member. In contrast, the connection plate opening is formed in the connection plate of the presser foot of the movement detector of the second aspect. Thus, even in a case where a member other than the movement detector, such as a needle bar of a sewing machine, is provided in the detachment direction of the housing, contact (interference) between the presser foot and the other member is suppressed.

According to a third aspect of the present disclosure, this specification discloses a movement detector attachable to a presser bar of a sewing machine including a bed. The movement detector includes a sensor and a housing. The sensor is configured to emit light downward toward a sewing workpiece and to detect the light reflected from the sewing workpiece to detect a movement amount of the sewing workpiece. The sewing workpiece is arranged on the bed and below the presser bar. The presser bar extends in an upper-lower direction. The housing accommodates the sensor. The housing includes a wall surface spaced from the sensor in a forward direction perpendicular to the upper-lower direction. The wall surface is formed with an insertion opening for inserting a presser foot. The movement detector of the third aspect has effects similar to those of the first aspect.

According to a fourth aspect of the present disclosure, this specification discloses a sewing system including a sewing machine and a movement detector. The sewing machine is configured to perform sewing on a sewing workpiece. The movement detector is configured to detect a movement amount of the sewing workpiece. The sewing machine includes a needle bar, a bed, and a presser bar. The needle bar extends in an upper-lower direction. A sewing needle is attachable to a lower end of the needle bar. The bed is located below the needle bar. The presser bar extends in the upper-lower direction. The needle bar and the presser bar are arranged in a front-rear direction perpendicular to the upper-lower direction. The movement detector includes a sensor and a housing. The sensor is configured to emit light downward toward the sewing workpiece and to detect the light reflected from the sewing workpiece to detect the movement amount of the sewing workpiece. The housing accommodates the sensor. The housing includes a wall surface spaced from the sensor in a forward direction that is a direction from the presser bar toward the needle bar in the front-rear direction. The wall surface is formed with an insertion opening for inserting a presser foot. The sewing system of the fourth aspect has effects similar to those of the first aspect.

A sewing systemand a movement detectoraccording to an embodiment will be described with reference to the drawings. The sewing systemshown inincludes a sewing machineand the movement detector. The sewing machineperforms sewing on a sewing workpiece C shown in. The movement detectoris attached to a presser barof the sewing machineand detects a movement amount of the sewing workpiece C.

The structure of the sewing machineto which the movement detectoris attached will be described with reference to. In the following description, the upper left, the lower right, the lower left, the upper right, the upper, and the lower inare respectively the left, the right, the front, the rear, the upper, and the lower of the sewing machineand the movement detector. The longitudinal direction of a bedand an armis the left-right direction of the sewing machine. The side on which a pillaris located in the left-right direction is the right side. The direction in which the pillarextends is the upper-lower direction of the sewing machine. A light emission direction (emission direction) D of a sensorof the movement detectordescribed later is downward. In the movement detectordescribed later, the direction from the sensortoward a front wallis forward.

As shown in, the sewing machineincludes the bed, the pillar, the arm, and a head. The bedis a base of the sewing machineextending in the left-right direction. The pillaris provided upright from a right end of the bed. The armextends leftward from an upper end of the pillarand faces the bedin the upper-lower direction. The headis provided at a left end of the arm.

A needle plateis provided on an upper surface of the bed. The needle plateis a plate that extends horizontally, that is, in a direction perpendicular to the upper-lower direction. The bedand the needle platesupport, from below, the sewing workpiece C which is sewn by the sewing machine. The bedaccommodates a hook (not shown) below the needle plate. The hook accommodates a lower thread (not shown) and entwines the lower thread with an upper thread (not shown). An LCDis provided on a front surface of the pillar. The LCDdisplays various images. The pillaraccommodates a sewing machine motor (not shown). The sewing machine motor drives the hook and a needle bar. The armaccommodates the upper thread and a main drive shaft (not shown). The upper thread is guided in the armtoward a sewing needle. The main drive shaft extends in the left-right direction and is rotationally driven by the sewing machine motor.

The headis provided with the needle barand the presser bar. The needle barextends in the upper-lower direction. The lower end of the needle barprotrudes downward from the lower end of the head. The sewing needleis detachably attached to the lower end of the needle bar. The needle baris driven to reciprocate in the upper-lower direction by the rotation of the main drive shaft. The sewing machineforms stitches on the sewing workpiece C by driving the needle barand the hook. The presser barextends in the upper-lower direction at a position rearward of the needle bar. The lower end of the presser barprotrudes downward from the lower end of the head. The lower end of the presser baris located above the needle plate. The movement detectoris attached to the lower end of the presser bar.

The structure of the movement detectorwill be described with reference to. The movement detectordetects the movement amount of the sewing workpiece C that is disposed on the bedbelow the presser bar, and outputs the detected movement amount to the sewing machine. The sewing machineadjusts the pitch of stitches formed on the sewing workpiece C by controlling driving of the sewing machine motor based on the movement amount of the sewing workpiece C. The presser footis attachable to and detachable from the movement detector. Although details will be described later, the presser footcontacts the sewing workpiece C from above and suppresses lifting (floating) of the sewing workpiece C (see). As shown in, the movement detectorincludes a housing, the sensor(see), a cable, a lock plate, a slider, and a mount body. The housinghas a rectangular parallelepiped shape longer in the front-rear direction than in the left-right direction. The housingaccommodates the sensor, the lock plate, and the slider.

The housingincludes an upper wall, a lower wall, and a peripheral wall. Each of the upper walland the lower wallextends horizontally. In a state where the movement detectoris attached to the presser barof the sewing machine, the lower wallis separated upward from the needle platewith a slight gap therebetween (refer to). The sewing workpiece C is disposed between the lower walland the needle plate, that is, the lower wallis located above the sewing workpiece C supported by the needle plate.

The peripheral wallextends in the upper-lower direction between a peripheral edge of the upper walland a peripheral edge of the lower wall. The peripheral wallincludes a left wall, a right wall, the front wall, and a rear wall. The left walland the right wallextend perpendicularly to the left-right direction and are arranged in the left-right direction. The front walland the rear wallextend perpendicularly to the front-rear direction and are arranged in the front-rear direction. The upper wallfaces upward, the lower wallfaces downward, the left wallfaces leftward, the right wallfaces rightward, the front wallfaces forward, and the rear wallfaces rearward. The front wallis spaced from the sensorin a detachment direction in which the presser footis detached.

The housingincludes an upper housingand a lower housing. The upper housingis an upper portion of the housing, and the lower housingis a lower portion of the housing. The housingis configured by stacking the upper housingon the lower housingfrom above.

The structure of the lower housingwill be described with reference to. The lower housingincludes a lower wall, an inclined wall, a middle wall, a left wall, a right wall, a front wall, and a rear wall. The lower wall, the inclined wall, and the middle wallare connected in this order from the front. Each of the lower walland the middle wallextends horizontally. The middle wallis located above the lower wall. The inclined wallconnects the rear end of the lower walland the front end of the middle wall, and extends rearward and upward. A sensor openingis formed in the lower wallto open through the lower wallin the upper-lower direction. The lower wallconstitutes the lower wallof the housing.

The left wallextends upward from the left ends of the lower wall, the inclined wall, and the middle wall. The right wallextends upward from the right ends of the lower wall, the inclined wall, and the middle wall. The front wallextends upward from the front end of the lower wall. The rear wallextends upward from the rear end of the middle wall. That is, the lower housingis a box that is open upward.

The lower housingaccommodates a circuit board(see) and the sensor(see). The circuit boardis a plate extending horizontally. The circuit boardhas a plate shape longer in the front-rear direction than in the left-right direction. The circuit boardextends from the front wallto the rear wallover substantially the entirety of the lower housingin the front-rear direction. Various electronic components are mounted on the circuit board. The circuit boardis connected to one end of the cable(see). Although not shown, the other end of the cableis connected to the sewing machine.

As shown in, the sensoris provided below the circuit board. The sensoris located above the lower wall. Although not shown, the sensorincludes a light emission portion (not shown) and a light detection portion (not shown). The light emission portion and the light detection portion are located above the sensor opening. The light emission portion emits light to the sewing workpiece C in order to detect the movement amount of the sewing workpiece C. The light emission portion is, for example, an infrared light emitting diode that emits infrared light. In a state where the movement detectoris attached to the presser barof the sewing machine, the light emission direction D of the light emission portion is downward. The emitted light passes through the sensor opening, reaches the sewing workpiece C, and is reflected. The light reflected by the sewing workpiece C passes through the sensor opening. The light detection portion detects light reflected from the sewing workpiece C and converts the light into an electric signal. The light detection portion is, for example, an infrared imaging element that detects infrared rays. The sensorperiodically emits light to the sewing workpiece C by the light emission portion, and detects the movement amount of the sewing workpiece C per unit time. The movement detectoroutputs the movement amount of the sewing workpiece C per unit time to the sewing machinevia the cable.

As shown in, a wallis provided at the upper end of the front wall. The wallextends horizontally. The front end of the wallis located at substantially the same position as the front end of the front wallin the front-rear direction. The rear end of the wallis located rearward of the rear end of the front wall(see) and forward of a rod(see). The left end of the wallis located between the center of the front wallin the left-right direction and the left end of the front wall. The right end of the wallis located between the center of the front wallin the left-right direction and the right end of the front wall. The wallconstitutes a lower end of an opening endthat defines an insertion openingdescribed later. The walland the front wallconstitute the front wallof the housing.

Recessesandare formed in the wall. The recessesandare portions recessed downward from the upper surface of the wall. The recess (groove)extends rearward from the front end of the wall. The rear end of the recessis located between the center of the wallin the front-rear direction and the rear end of the wall. The recessis located between the center of the wallin the left-right direction and the left end of the wall. The recessis located leftward of the center of the lower housingin the left-right direction. The recessis located on an insertion path of the presser foot(see), and a protrusionA of the presser footdescribed later fits to the recess. The recessis located at the right rear end of the wall. The front end of the recessextends in the left-right direction and is located at substantially the center of the wallin the front-rear direction. The left end of the recessextends in the front-rear direction and is located between the recessand the right end of the wall.

The lock plateis provided above the circuit board. The lock plateis a leaf spring and is elastically deformable in the upper-lower direction. The material of the lock plateis, for example, a metal such as phosphor bronze. The lock platelocks the presser foot(see). The slideris provided above the lock plate. The sliderfunctions as a lock release mechanism for releasing the lock of the presser footby the lock plate.

The structures of the lock plateand the sliderwill be described with reference to. The lock plateincludes a base portion, extending portionsand, a fitting portion, and a protruding portion. The base portionis a plate that extends horizontally and is longer in the front-rear direction than in the left-right direction. An openingis formed in a front end portion of the base portionto open through the base portionin the upper-lower direction. An openingis formed in a rear end portion of the base portionto open through the base portionin the upper-lower direction. The base portionis fixed to the lower housingby screws (not shown) at a position above the circuit boardthrough the openingsand. The base portionis located at substantially the same position as the bottom surface of the recessin the upper-lower direction.

The extending portionis a plate extending upward from the front end of the base portion. The upper end of the extending portionis located at substantially the same position as the upper end of the wallin the upper-lower direction. The extending portionis a plate extending forward from the upper end of the extending portion. The extending portionextends horizontally, and the size of the extending portionin the front-rear direction is larger than the size of the extending portionin the left-right direction. The front end of the extending portionis located rearward of the front end of the recessand upward of the bottom of the recess. A front end portion of the extending portionis located at a position overlapping the recessin a plan view.

A cutoutis formed in the extending portion. The cutoutis a portion of the extending portionthat is cut out rightward from the left end of the extending portion. The right end of the cutoutis located at substantially the center of the extending portionin the left-right direction. The front end of the cutoutis located between the center of the extending portionin the front-rear direction and the front end of the extending portion. The front end of the cutoutis located at a position overlapping the recessin a plan view, and is located at substantially the same position as the rear end of the recessin the front-rear direction. The rear end of the cutoutis located substantially at the center of the extending portionin the front-rear direction. The rear end of the cutoutis located at substantially the same position as the rear end of the wallin the front-rear direction.

The fitting portionis a plate shape that is bent in a protruding shape that protrudes upward with respect to the extending portionas a whole. The fitting portionincludes an inclined portionand an extending portion (horizontal portion). The inclined portionextends rearward and upward from an edge of the extending portionthat defines the front end of the cutout. The extending portionextends rearward from the rear upper end of the inclined portion. The fitting portionis located on the insertion path of the presser foot(see), and fits to an openingA of the presser footdescribed later.

The protruding portionis a plate that is bent in a protruding shape protruding upward from the upper surface of the extending portion. The protruding portionis spaced rearward from the fitting portion. The protruding portionhas extending portions (inclined portions)and. The extending portionextends forward and upward from an edge of the extending portionthat defines the rear end of the cutout. The front upper end of the extending portionis located at substantially the same position as the upper end of the extending portionin the upper-lower direction. The extending portionextends forward and downward from the front upper end of the extending portion. The front lower end of the extending portionis located at substantially the same position as the extending portionin the upper-lower direction.

The lock plateextends horizontally as a whole. In the lock plate, the base portionis fixed to the upper housing, whereas the extending portionforms a free end that is not fixed to a component other than the lock plate. Thus, when a load is applied to the extending portionfrom above, the extending portionis elastically deformable, and thus bends downward via the extending portionwith the base portionas a support.

As shown in, the sliderincludes a base portion, a lever, platesand, and a compression coil spring. The base portionis provided on the left side of the base portion. The base portionhas a box shape longer in the front-rear direction than in the left-right direction. An openingand a cutoutare formed in the base portion. The openingis formed to open the base portionforward. The cutoutis formed to cut out the upper wall of the base portionrearward from the front end of the upper wall of the base portion.

The compression coil springextends in the front-rear direction and is accommodated in the base portion. The rear end of the compression coil springis connected to the rear wall of the base portion. The front end of the compression coil springis connected to a protrusiondescribed later. The base portionis always urged rearward by the compression coil spring.

The leverprotrudes upward from a rear upper end of the base portion. An upper end of the leveris exposed to the upper side of the housingfrom a slider openingdescribed later (see). The plateprotrudes forward from the front end of the base portion. The plateextends longer in the front-rear direction than in the left-right direction in horizontal directions. The plateis located at substantially the center of the base portionin the upper-lower direction. In a state where the presser footis attached to the movement detector, the plateis located rearward of an insertion plateA described later.

The plateprotrudes rightward from the right end of the plate. The plateextends longer in the front-rear direction than in the left-right direction in horizontal directions. The plateis located rearward of the protruding portion. The rear end of the plateis located at substantially the same position as the rear end of the platein the front-rear direction. The front end of the plateis at the same position as the front end of the platein the front-rear direction. Hereinafter, the plateand the plateare collectively referred to as a slider wall. The slider wallis located above the extending portion, and is located at substantially the same position as the protruding portion, the fitting portion, and the insertion plateA in the upper-lower direction.

The slideris not fixed to the housing, and is slidable in the front-rear direction while being guided by the slider opening. The slider wallslides in the front-rear direction inside the housing. The base portionand the slider wallof the slider, which slide in the front-rear direction inside the housing, are collectively referred to as a slider plate. The slider plateextends horizontally as a whole.

The structure of the upper housingwill be described with reference to. The upper housingincludes an upper wall, a left wall, a right wall, a rear wall, a front wall, and the protrusion. The upper wallextends longer in the front-rear direction than in the left-right direction in horizontal directions. The front end of the upper wallis located forward of the front end of the front wall. The upper wallconstitutes the upper wallof the housing.

The left wallextends downward from the left end of the upper wall. The right wallextends downward from the right end of the upper wall. The rear wallextends downward from the rear end of the upper wall. The front wallextends downward from the front end of the upper wall. That is, the upper housingis a box that is open downward. The left walland the left wallconstitute the left wallof the housing. The right walland the right wallconstitute the right wallof the housing. The rear walland the rear wallconstitute the rear wallof the housing.

The protrusionprotrudes downward from the upper wall. The lower end of the protrusionis located between the lower end of the upper housingand the center of the upper housingin the upper-lower direction. Although not shown, the protrusionis inserted into the base portionvia the cutout. The protrusionis connected to the front end of the compression coil springinside the base portion. The protrusionis located at substantially the center of the upper wallin the left-right direction and the front-rear direction.

The upper wallis formed with the slider opening, a cable opening, and a shaft opening (not shown). The slider openingis formed through the upper wallin the upper-lower direction. The slider openingextends in the front-rear direction. The front end of the slider openingis located between the center of the upper wallin the front-rear direction and the rear end of the upper wall. The rear end of the slider openingis located at substantially the rear end of the upper wall. The leveris inserted through the slider opening, and the slider openingguides the sliderto slide in the front-rear direction.

The cable openingis formed through the left rear end of the upper wallin the upper-lower direction. The cableis inserted through the cable opening. The shaft opening is formed through a left end portion of the upper wallin the upper-lower direction. The shaft opening is located between the front end of the upper walland the center of the upper wallin the front-rear direction. The rodprotrudes above the upper wallthrough the shaft opening.

As shown in, the rodis fixed to the upper housing. The rodis located between the center of the housingin the front-rear direction and the front end of the housing. The rodis located between the center of the housingin the left-right direction and the left end of the housing.

The mount bodyis provided at the upper wall. As shown in, the mount bodyincludes a lower wall, an upper wall, and a mount wall. The lower walland the upper wallextend perpendicularly to the upper-lower direction. The lower wallis formed with an openingthat is formed through the lower wallin the upper-lower direction. The upper wallis formed with an openingthat is formed through the upper wallin the upper-lower direction. The openingand the openingare arranged in the upper-lower direction. The rodis inserted through the openingsandand fixed to the lower walland the upper wall.

As shown in, the mount wallextends in the upper-lower direction between the right end of the lower walland the right end of the upper wall. The mount wallis located at substantially the center of the upper wallin the left-right direction. The front end of the mount wallis attached to the presser bar. The movement detectoris mounted to the sewing machineby fixing the mount wallof the mount bodyto the presser bar.

The lower end of the front wallis located at substantially the same position as the upper end of the front wallin the upper-lower direction. The front end of the upper wallis located forward of the front end of the front wall, and thus the front end of the front wallis located forward of the front end of the front wall. The rear end of the front wallis located at substantially the same position as the front end of the front wallin the front-rear direction.

A cutoutis formed in the front wall. The cutoutis recessed upward from the lower end of the front wall. The upper end of the cutoutis located between the upper end of the front walland the center of the front wallin the upper-lower direction, and is located above the upper end of the wall. The left end of the cutoutis located at substantially the same position as the left end of the wallin the left-right direction. The right end of the cutoutis located at substantially the same position as the right end of the wallin the left-right direction. Thus, the insertion openingis formed in the front wallof the housing. The insertion openingcauses the housingto open forward. The opening endof the insertion openingis defined by the upper end of the walland the cutout. The insertion openingis an opening for inserting the presser footinto the housing. A portion of the front wallthat protrudes forward from the upper end of the insertion openingis referred to as an eaves portion.

The structure of the presser footwill be described with reference to. The presser footis available in a plurality of types, and has different shapes according to sewing operations. One selected from a plurality of types of presser feetis attachable to and detachable from the movement detector. The plurality of types of presser feetof the present embodiment include a presser footA (see), a presser footB (see), and a presser footC (see). The material of the presser feetA andB and portions of the presser footC other than a presser plateC described below are metals such as aluminum alloys, for example.

As shown in, the presser footA includes a presser plateA, a connection plateA, and the insertion plateA. The presser plateA is perpendicular to the upper-lower direction and has a substantially circular shape in a plan view. In a state where the presser footA is attached to the movement detector, the presser plateA contacts the sewing workpiece C from above, and suppresses lifting (floating) of the sewing workpiece C (refer to).