Embroidery sewing machine

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an embroidery sewing machine to which either one of two types of frames, namely, a cylindrical frame holding cylindrical cloth and a flat frame holding flat cloth, is attachable so that embroidery can be formed on either cloth.

2. Description of the Related Art

In conventional embroidery sewing machines forming embroidery on cloth (flat cloth), a rectangular flat frame holding the flat cloth is set on a carriage. The flat cloth is moved in horizontal (X, Y) directions so that embroidery is formed thereon. On the other hand, in conventional embroidery sewing machines forming embroidery on cylindrical cloth such as caps and shirt-body or shirt-sleeves, a cylindrical frame holding cylindrical or baggy cloth is set on a carriage. The cylindrical frame is moved in the axial direction (Y direction) and rotational direction.

Recently, various types of embroidery sewing machines have been proposed and put into practice to which either flat frame holding the flat cloth or cylindrical frame holding the cylindrical cloth is selectively attached so that embroidery can be formed on either flat cloth or cylindrical cloth. As one of such embroidery sewing machine, JP-A-H11-200228 discloses an industrial embroidery sewing machine.

This embroidery sewing machine has, on a working table, a rectangular cloth feeding frame holding flat cloth. The cloth feeding frame is moved in the X direction (right-left direction) and Y direction (front-back direction) by an X-direction driving mechanism and a Y-direction driving mechanism. A cap frame device having a rotating frame is connected to the aforementioned cloth feeding frame, and a cap frame (cylindrical frame) that holds the cap (cylindrical cloth) is detachably attached to the aforementioned rotating frame. This enables a cap frame and the cloth feeding frame to move integrally in the front-back direction (Y direction) while the movement of cloth feeding frame in left-right direction is converted to the rotation of the rotating frame (cap frame) via a wire wound on the aforementioned rotating frame.

This wire-driven method, which applies a wire as a medium to transmit the rotational movement to the rotating frame has the following conditions:

(1) In a wire-driven method, to ensure the precision of the halt location, prescribed tension of high magnitude needs to be maintained on the wire.

(2) In the production of the rotating frame, high precision of machining such as out of roundness tolerance and circular deficit tolerance is required apart from tolerance of considerable time frame.

Hence, the rotating frame is made of metal of high rigidity. However, a metallic rotating frame is heavy and is proportionally affected by increased inertia, thereby requiring a large drive motor with high torque. This leads to cost increase of the embroidery sewing machine and a larger space to store the large drive motor.

However, sewing machines for domestic use require low cost and smaller size in relative to those which are not of domestic use. Therefore, it is undesirable to adopt the aforementioned wire-driven method. Instead, a simpler mechanism is required.

Given the above, the inventor conceived a rotational drive method, comprising a rack-and-pinion mechanism, in which a rack was attached to the cloth feeding frame side and a pinion in mesh with the rack was provided on the cylindrical frame side so as to be coaxial with the rack, thereby realizing the conversion of left-right directional movement of the cloth feeding frame to a rotational movement of rotational frame (cylindrical frame). This method also allows the rotationally driven rotational frame and cylindrical frame to be configured as synthetic-resin components.

SUMMARY OF THE INVENTION

It is of great significance on adopting the rack-and-pinion mechanism to configure a drive transmission where the distance of the horizontal (left-right) movement of the flat frame equals the rotational distance of the cylindrical frame.

This is because if such equation is not achieved, embroidery data cannot be shared between the flat frame and the cylindrical frame, meaning that separate embroidery data that is, embroidery data for flat frame and embroidery data for cylindrical frame need to be prepared to create the same embroidery from different frames.

An object of the present invention is to provide an embroidery sewing machine which is capable of forming embroidery on both flat cloth and cylindrical cloth employing a relatively simpler mechanism and which is capable of sharing the same embroidery data between a case where the flat frame is used and a case where the cylindrical frame is used.

A first embroidery machine of this invention, capable of forming embroidery on both flat cloth and cylindrical cloth by selectively attaching a flat frame to hold flat cloth and cylindrical frame to hold cylindrical cloth has a feature of having a cylinder bed, a first carriage set to move to the first direction to which the cylinder bed extends, a first drive unit to move the first carriage in a first direction, a second carriage having a flat frame attachment part to which a detachable flat frame is attached and which can be moved in a second direction perpendicular to the first direction, a cylindrical frame drive unit having a cylindrical frame attachment part to which a cylindrical frame is detachably attached and supported by the first carriage so as to be rotatable about an axis parallel to the first direction, a second driving unit driving either second carriage or cylindrical frame drive unit, and a rack-and-pinion mechanism including a rack member provided on the second carriage and a pinion provided on an outer periphery of the cylindrical frame drive unit and having a reference pitch diameter substantially equal to an outer diameter of a cloth stretching surface of the cylindrical frame, either one of the rack member and the pinion transmitting driving force to the other.

In case of forming embroidery on flat cloth, the relevant flat cloth is held on the flat frame and attached to the flat frame attachment part of the second carriage. When the first carriage is moved in the first direction by the first drive unit, the second carriage and cylindrical frame drive unit is moved in the first direction and the flat frame and the cylindrical frame selectively attached moves in the first direction by the same distance.

When the second carriage is moved in the second direction by the second drive unit, the drive force is transmitted to the cylindrical frame drive unit via the rack-and-pinion mechanism. Alternatively, when the cylindrical frame drive unit is moved by the second drive unit, the drive force is transmitted to the second carriage via the rack-and-pinion mechanism and moved to the second direction.

At this time, because the reference pitch diameter of the pinion is configured so as to be nearly equal to the outer diameter of the cloth stretching surface, the distance of movement in the direction taken by the flat frame attached to the second carriage nearly equals the distance of rotation made by the surface of the cylindrical frame attached to the cylindrical frame drive unit. Therefore, the embroidery data for flat frame and cylindrical frame can be shared.

In the present invention, because the driving force is transmitted by the rack-and-pinion mechanism, the driving force is accordingly transmitted from the second drive means to both the second carriage and the cylindrical frame drive unit and moves the second carriage and rotates the cylinder drive unit respectively.

Depending on which of the second carriage or cylindrical frame drive unit is driven by the second drive unit, that is, to which the second driving force of the second drive unit is transmitted first will result in the following difference in operation and effect.

It can be configured so that the second driving means drives the second carriage in the second direction to transmit the driving force to the cylinder driving unit via the rack-and-pinion mechanism. Because the second carriage (flat frame) is heavy, the second carriage is affected by a large magnitude of inertia thereby requiring larger torque as compared to driving cylindrical frame drive unit (cylindrical frame).

By configuring the second driving unit to be transmitted to a second carriage first, the transmission efficiency improves as compared to the case configured otherwise and becomes an advantage of the mechanism.

On the other hand, it can be configured so that the second drive unit rotatably drives the cylindrical frame drive unit, which is in turn transmitted to the second carriage via the rack-and-pinion mechanism. In this case, the second drive unit will generally use a motor as a driving source, so as a driving mechanism, should simply transmit the rotational drive of the motor as a rotational drive of the cylindrical frame driving unit. Therefore, compared to the mechanism in which the rotational drive is converted to a linear drive, the drive unit can be made simpler.

Now, the cylindrical frame attachment part and cylindrical frame move in the first direction and rotates in the axial direction over the outer parameter of the cylinder bed part leaving some space. While it is desired to configure the cylinder bed part as thick as possible to secure tolerability, in order to hold relatively small (thin) cylindrical cloth (e.g. shirt sleeves or pockets) there are cases where a small cylinder attachment part and cylindrical frame is desirable.

In the present invention, the cylindrical frame can be configured so that it is connected to the cylindrical frame drive unit and cylindrical frame attachment unit via outer-fitting cylindrical connection part.

In the present invention, the cylindrical frame including the cylindrical connection part can be integrally formed from synthetic resin and the cylindrical frame drive unit can also be configured by synthetic resin. This enables the weight and cost reduction of cylindrical frame and the cylindrical connection part.

In the aforementioned cylindrical frame attachment part and cylindrical connection part, a locating fitting part can be provided to determine the relative location of the rotational direction of the cylindrical frame attachment part and cylindrical connection part.

This enables the location of the rotational direction of the cylindrical frame attachment part and cylindrical connection part when the cylindrical frame is attached to the cylindrical frame drive unit with ease and at the same time, prevents without fail, the displacement of the cylindrical frame against the cylindrical frame drive unit during the rotation process and improves the precision of the rotational location of the cylindrical frame.

In the present invention, the reference pitch diameter of the pinion is nearly equal to the outer diameter of the cloth stretching surface of the cylindrical frame in the present invention. “Nearly equal” is to indicate, the reference pitch diameter being equal to, slightly smaller than, and slightly larger than the outer diameter of the cloth stretching surface of the cylindrical frame.

As the embroidery creation proceeds, the seams formed in the process may pull the cloth tensely held in the embroidery frame causing it to shrink. In case such shrinking of the cloth occurs, the size of an embroidery pattern may become slightly smaller than the prescribed size.

This shrinking of the cloth is more significant when using cylindrical frames than flat frames because of the increased difficulty in holding the cloth when using cylindrical frames. By configuring the reference pitch diameter of the pinion slightly smaller than the outer diameter of the cloth stretching surface of the cylindrical frame, the rotational distance of the cloth stretching surface of the cylindrical frame becomes slightly larger than the distance of the horizontal movement of the flat frame. This enables the forming of the embroidery that is the same in size as the one formed by using the flat frame even when using cylindrical frame and aforementioned shrinking of the cloth occurs.

Alternatively, the pinion comprises a profile-shifted gear and the profile-shifted gear has a working pitch circle with a diameter slightly smaller than an outer diameter of the cloth stretching surface of the cylindrical frame. Similarly, even in cases where cylindrical frame is used and shrinking of the cloth occurs, the negative effects of the cloth shrinking can be minimized and enable the forming of the embroidery that is the same in size as the one created by using the flat frame. Additionally, an amount of backlash of the gear can be reduced without changing the relative placement of the rack and pinion and this in turn improves the precision of the rotation location of the cylindrical frame.

A second embroidery machine of this invention, capable of performing embroidery on both flat cloth and cylindrical cloth by selectively attaching a flat frame to hold flat cloth and a cylindrical frame to hold cylindrical cloth, the embroidery sewing machine comprising a cylinder bed, a first carriage set to move in a first direction in which the cylinder bed extends, a first driving unit which moves the first carriage in the first direction, a second carriage having a flat frame attachment part to which a flat frame is detachably attached and which is movable in a second horizontal direction perpendicular to the first direction, a cylindrical frame drive unit having a cylindrical frame attachment part to which a cylindrical frame is detachably attached and supported by the first carriage so as to be rotatable about an axis parallel to the first direction, a second driving unit driving either second carriage or cylindrical frame drive unit, and a rack-and-pinion mechanism including a rack member provided on the second carriage and a pinion provided on an outer periphery of the cylindrical frame drive unit, the rack-and-pinion mechanism transmitting a driving force of the second carriage to the cylindrical frame attachment part.

In case of creating embroidery on flat cloth, the relevant flat cloth is held on the flat frame and attached on the flat frame attachment part of the second carriage. When the first carriage is moved to the first direction by the first drive means, the second carriage and cylindrical frame drive unit is moved to the first direction and the flat frame and the cylindrical frame selectively attached moves to the first direction in the same distance.

When the second carriage is moved in the second direction by the second drive unit, the driving force is transmitted to the cylinder drive unit via the rack-and-pinion mechanism and rotation is performed.

The second carriage (flat frame) is affected by a large magnitude of inertia because of its heavy weight and requires larger torque compared to driving cylinder drive unit (cylindrical frame).

By configuring the second driving unit to be transmitted to second carriage first, the transmission efficiency improves compared to the case configured otherwise and becomes an advantage of the mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become clear upon reviewing the following description of the embodiment with reference to the accompanying drawings, in which:

FIG. 1 is a side view of embroidery sewing machine relating to one embodiment of this invention;

FIG. 2 is a plan view of carriage of X direction;

FIG. 3 is a side view of carriage of X direction and cylindrical frame drive unit;

FIG. 4 is a longitudinal front section taken along line 4-4 of FIG. 3;

FIG. 5 is a plan view of flat frame;

FIG. 6 is a diagonal view of cylindrical frame;

FIG. 7 is a plan view of carriage of X direction with the cylindrical frame attached;

FIG. 8 is a plan view of carriage part of X direction with the cylindrical frame attached;

FIG. 9 is a side view of carriage part of X direction with the cylindrical frame attached; and

FIG. 10 is a front view of the positive shift pinion showing the other embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the invention applied to an embroidery sewing machine for domestic use will be described by referring to FIGS. 1 to 9. First, FIG. 1 shows an overview of the embroidery sewing machine related to this invention. The main body of this embroidery sewing machine 1 includes a horizontal base 2 placed on a working table 9 etc., a sewing pillar 3 extending upward from the rear of the base 2, a cylinder bed 4 extending horizontally in the forward direction from a lower part of the pillar 3, a sewing arm 5 extending in a forward direction in an upper end of the pillar 3.

Now, in this embodiment, the extending direction (front-back direction) of cylinder part 4 is defined as Y direction (first direction) and the horizontal direction (left-right) direction perpendicular to it is defined as X direction (second direction).

The arm 5 encloses a main shaft driven by a sewing machine motor, a needle bar vertical drive mechanism vertically driving the needle bar with the sewing needle 7 attached, a thread take-up lever drive mechanism and the like, though these are not shown in the drawings. Also are not shown but in the cylinder bed 4 are provided a loop taker which forms an embroidery seam in cooperation with the sewing needle 7 and a thread-cutting mechanism to cut the upper thread and lower thread on completion of embroidery. In the pillar 3, a hand pulley is provided to vertically move the needle bar 7 by manually rotating the main shaft by the operator.

Now, the sewing machine 1 of the embodiment is capable of forming embroidery on flat cloth (not shown) and cylindrical cloth (not shown) by selectively attaching a flat frame 11 (refer FIG. 5) to hold a flat cloth (for example, unprocessed cloth) and a cylindrical frame 16 (see FIG. 6) to hold cylindrical (bag-shaped) cloth (for example, a cap, abdominal part or sleeve part of a t-shirt). When forming embroidery, the flat frame 11 holding the flat cloth moves horizontally over the cylinder bed 4 in the X direction and Y direction. On the other hand, the cylindrical frame holding the cylindrical cloth moves in the Y direction as if to cover an upper half of the outer periphery of the cylinder bed 4 as well as rotating around the shaft extending in the Y direction. The mechanism for the above-described movement will be explained in the following.

First, as shown in FIGS. 2 to 4, a Y direction carriage 21 as the first carriage is provided in the proximal end side of the cylinder bed 4 so as to be movable in the Y direction. The Y direction carriage 21 has a carriage support plate 23 placed on the upper part of a base plate 22 which is broad in the left-right direction and extends in the vertical direction. As shown in FIG. 3, a carriage support plate 23 is in an L-shape when viewed from the side, formed integrally by a vertical wall part 23a affixed on the upper part of the base plate 22 and a horizontal wall 23b extending in a forward-horizontal direction from the upper part of the vertical wall 23a. Now, as shown in FIG. 4, the central part of the base 22 has a hole through which the cylinder bed 4 extends.

The Y direction carriage 21 is moved in the Y direction by a Y direction drive mechanism as a first driving unit. Though figure representation and detail explanations are omitted, the Y direction drive mechanism is configured by a Y direction drive motor comprising a stepping motor and mechanisms to convert the driving force to linear movement in a Y direction and is placed on the part which extends from the pillar 3 and base part 2.

On the base plate 22 of the Y direction carriage 21, an x direction carriage 30, which is a second carriage, is provided on the upper part of the base plate 22 and a cylindrical frame drive unit 65 is provided on the lower part of the base plate 22. In the front side of the X direction carriage 30, flat frame attachment mechanisms 45 and 55 which serve as flat frame attachment parts to which the flat frames 11 are detachably attached. Also, in the front part of a cylindrical frame drive unit 65, a cylindrical frame attachment part 65a to which the cylindrical frame is detachably attached is provided as to cover the outer periphery of the cylinder bed 4.

Out of the above configuration, the X direction carriage 30 is explained first. As indicated in FIGS. 2 to 4, the left and right ends of the horizontal wall part 23b of the carriage support plate are partially bent downward and a guide shaft 31 extending in the X direction is bridged between the bent ends.

Also, as shown in FIG. 4, in the front part of the vertical wall 23a of the carriage support plate 23, a guide rail 23c extending in the X direction is provided by carving out a part of the vertical wall 23a in the forward direction.

The X direction carriage 30 has a horizontally flat plated carriage base plate 32 and a support member 33 which is generally u-shaped (see FIG. 4) when viewed at the front. As indicated in FIG. 2, the holes formed on the left and right upper ends of the support member 33 are inserted movably on the guide shaft 31. Along with this, on the rear end of the central part in the left-right direction of the carriage base plate 32, the guide support 32a (see FIG. 4) which is raised one level higher in a crank-like profile (when viewed from the side) is formed integrally. On the upper surface of the guide support part 32a, a guide block 34 is affixed. A rail groove formed on the guide block 34 is engaged with the guide rail part 23c in a sliding manner. This enables the X direction carriage 30 to be supported movably in the X direction by guide shaft 31 and guide rail part 23c.

As shown in FIGS. 2 to 4, on the front side of the vertical wall 23a of the carriage support plate 23, pulleys 35 and 37 are rotatably mounted on pivotal shafts 36 and 37 respectively. A timing belt 39 is bridged across the pulleys 35 and 37. A front of the guide block 34 is partially connected to the timing belt 39.

As shown in FIG. 3, in the rear side of the right side pulley 35, a second driven gear 40 of large-diameter is integrally provided. On the other hand, on the base plate 22, a first driven gear 41 having a small diameter part is rotatably mounted in the front side of the large-diameter part and the second driven gear 40 is in mesh engagement with the small-diameter part. Further, in the rear surface, a carriage drive motor comprising a stepping motor is mounted facing forward and a drive gear 43 secured on the drive shaft is in mesh engagement with a large-diameter part of the first driven gear 41.

As the result of the foregoing construction, when the drive gear 43 is rotated by the carriage motor 42, the pulley 35 is rotatably driven via the first driven gear 41 and the second driven gear 40 sending the timing belt 39 to the X direction. The X direction carriage 30 is moved in the X direction via the guide block 34 connected to the timing belt. Therefore, the second drive unit comprises the first driven gear 41 and the second driven gear 40, timing belt 39, and carriage drive motor 42. On the bottom surface of the carriage base plate 32 of the X-direction carriage, a rack member 76 constituting the rack-and-pinion mechanism is provided as will be described later.

Next, the flat frame attachment mechanisms 45 and 55 as the flat frame attachment parts provided on X direction carriage will be explained. First, the flat frame 11 is explained. As shown in FIG. 5, the flat frame 11 is provided with the outer frame 12 and inner frame 13 detachably fitted in the inner part of the outer frame 12 together forming a nearly oblong frame with round corners. The flat frame 11 holds the flat cloth within the inner frame 13 in a tightly stretched manner by clipping the process cloth (flat cloth) not shown in between the outer and inner frames 12 and 13. A pair of left and right attachments 14 and 15 are fixed to the rear arm of the outer frame 12. Oblong engagement holes 14a and 15a are formed in the attachments 14 and 15 respectively.

As shown in FIG. 2, the flat frame attachments 45 and 55 are provided on the left and right parts of the carriage 30 in a symmetrical manner. Therefore, the right side flat frame attachment mechanism 45 will be explained to represent both sides of the symmetry. The flat frame attachment mechanism 45 includes the carriage base 32, a frame holding member 46 and a frame holding lever 48 both mounted on the carriage base 32.

That is, the frame holding member 46 is secured to the upper surface of the right end of the carriage base plate 32. The frame holding member 46 is formed into the shape of a gate (thin inverted U shape) and has such a prescribed width and height that the right attachment 15 of the flat frame 11 is insertable thereinto. An oblong attachment hole 46a is formed in the upper surface of the frame holding member 46. A frame holding lever 48 is pivotally mounted via a pivot pin 49 on an L-shaped (side view) pivot 47 secured on the carriage base plate 32. An engagement part 48a projecting downward from the distal end (left end) of the frame holding lever 48 is integrally formed and fitted into the attachment hole 46a from above.

The engagement part 48a of the frame holding lever 48 is biased downward by the spring force of a coil spring 51 wound on the pivot pin 49 disposed immediately behind it. Also, an inclined guide surface is formed on the front lower end of the engagement part 48a. An operating part 48b operable by finger pressing of the operator is provided integrally on the rear end (right end) of the frame holding lever 48.

Likewise, the left-side attachment mechanism 55 is also provided with a frame holding member 56 having an attachment hole 56a, a frame holding lever 58 which is pivotally mounted via a pivot pin 59 on a pivot 57, includes integrally formed engagement part 58a and operational part 58b and is elastically biased by a coil spring 60.

As the result of the above-described configuration, when the attachments 15 and 14 of the flat frame 11 are inserted into the corresponding frame holding members 46 and 56 of the flat frame attachment mechanisms 45 and 55 respectively, the engagement parts 48a and 58a of the frame holding levers 48 and 58 floated by the guide of the guiding surface and fitted into the engagement holes 15a and 14a of the attachments 15 and 14 respectively. As a result, as shown in FIG. 7, the flat frame 11 is fastened on the X direction carriage 30. When the operator operates the operational the parts 48b and 58b of the frame holding lever 48 downward, the engagement parts 48a and 58a and the engagement holes 15a and 14a are released from the engaged state. As a result, the flat frame 11 can be pulled toward the operator thereby to be detached.

Next, a cylindrical frame drive unit 65 is explained. As indicated in FIGS. 2 and 3, a cylindrical frame drive unit 65 is made from a synthetic resin. The cylindrical frame drive unit 65 is formed into a cylindrical shape and has a slightly larger inner diameter than the cylinder bed 4. As shown in FIG. 3, a cross-sectional V-shaped annual guide groove 66 is formed on the whole on the outer periphery of the rear side of the cylindrical frame drive unit 65. Also, a pinion 67 constituting the rack-and-pinion mechanism 75 is provided integrally in a range of 200 degrees of the upper half part.

As opposed to this, circular pivotal rollers 68 are mounted on pivotal volts 69 further pivotally mounted on the base plate 22, as shown in FIGS. 3 and 4. The roller 68 is located at three locations on the front side (at angular intervals of 120 degrees). The cylindrical frame drive unit 65 is located so as to cover the outer periphery of the cylinder bed 4 by engaging the three pivotal rollers 68 to an annular guide groove 66 from the outside and is rotably supported around the shaft extending in the Y direction by the Y direction carriage 21.

A cylindrical frame attachment 65a to which the cylindrical frame 16 in a cylindrical form is detachably attached is provided on the first half part of the cylindrical frame drive unit 65. As shown in FIGS. 3 and 4, a location projection 65b as a location fitting part is formed on the lower end of the cylindrical frame attachment 65a, extending in the Y direction on the lower end of the cylindrical frame attachment 65a. A holding roller 70 is provided to fix the cylindrical frame 16 to two portions near the upper part of both sides (left and right) of the cylindrical frame attachment 65a in an engaging manner as shown in FIGS. 2 and 3. The holding rollers 70 are mounted on the cylinder drive unit 65 via a plate spring elastic member 71, and is biased toward the outer peripheral surface of the cylindrical frame attachment 65a.

Now, the cylindrical frame 16 will be explained hereafter. As shown in FIG. 6, the cylindrical frame 16 is made from a synthetic resin and has a cylindrical connection 16a located on the rear end side and fitted with an outer periphery of the cylindrical frame attachment 65a and a cloth holding part 16b located in front of the attachment 65a. The cylindrical connection 16a and the cloth holding part 16b are formed integrally with each other. An opening 16c of the prescribed range is formed in a nearly oblong shape for embroidery sewing. An annular flange part 16d is integrally provided on a boundary of the cylindrical connection part 16 and the cloth holding part 16b. The rear end part of the cloth suppressing frame 17 is pivoted on this flange part 16d.

The cloth suppressing frame 17 is formed into a curved (contoured in a semi cylindrical form) frame along the upper surface part of the cloth holding part 16b and has an opening corresponding to the opening 16c. The cloth suppressing frame 17 is located in between the closed location so as to overlap with the upper surface of the cloth holding part 16b as shown in FIG. 6 and in the opened location with the front side opened upwards in a vertically movable state. The operator is to arrange the cloth suppressing frame 17 in the closed location, fit the cylindrical cloth (not shown) on which embroidery is formed to the cloth holding part 16 from the front and close the cloth suppressing frame 17 to a closed location.

When held between the cloth holding frame 16b and the cloth suppressing frame 17 in the closed state of the cloth suppressing frame, the cylindrical cloth (not shown) is held within the opening 16c in a tightly stretched state. Therefore, the outer peripheral surface of the cloth holding part 16b is assumed as the cloth stretching surface 16f to hold the cylindrical cloth by the cloth suppressing frame 17.

Also, the cylindrical connection 16a has such an inner diameter that the cylindrical connection 16a is fitted with the outer periphery of the cylinder attachment 65a. The cylindrical connection 16a has engagement recesses 16g (only one is shown) formed on two locations near the upper right and left portions so as to correspond to the holding rollers 70. Further, as shown only in FIG. 9, a positioning recess 16h is formed extending in the Y direction on the lower part of the cylindrical connection 16a as the location fitting part which engages the location projection part 65b.

As shown in FIGS. 8 and 9, when the cylindrical connection 16a is fitted with the outer periphery of the cylinder attachment 65a from the front so that the cylinder bed 4 is passed through the cylindrical frame, the cylindrical frame 16 is attached to the sewing machine. At this time, the positioning recess 16h of the cylindrical connection 16a slides onto the positioning projection 65b on the lower end of the cylindrical attachment 65a. Along with this, two sets of holding rollers 70 are engaged with the two engagement recesses 16g of the cylindrical frame 16. As a result, the cylindrical frame 16 is attached to the cylindrical frame drive unit 65 while being positioned with respect to the rotation direction and Y direction.

Now, in this embodiment, the X direction driving force of the X direction carriage 30 driven by the carriage drive motor 42 is transmitted as a rotational driving force of the cylindrical frame drive unit 65 via a rack-and-pinion mechanism 75. As shown in FIGS. 34, a rack 76 extending in the X direction is fixed to the underside of the carriage base plate 32. A pinion 67 is formed on the outer periphery of the cylindrical frame drive unit 65. The rack 76 and the pinion 67 are in mesh engagement.

When the X direction carriage 30 is moved in the X direction by the carriage drive motor 42, the cylindrical frame drive unit 65 is driven via the rack-and-pinion mechanism 75 in synchronization with the carriage 30. At this time, the reference pitch diameter D0 (see FIG. 4) is set to be nearly equal to the outer diameter D1 (see FIG. 9) of the cloth stretching surface 16f of the cylindrical frame 16. In this embodiment, the reference pitch diameter D0 is configured to be slightly smaller than the outer diameter D1 of the cloth stretching surface 16f.

Now, though figure representation and detailed explanation will not be given, the embroidery sewing machine 1 is provided with a control unit with a configuration inclusive of a microcomputer.

As well known in the art, the control unit controls the sewing machine motor, Y direction drive motor to move the Y direction carriage 21, and the carriage drive motor 42 based on embroidery data etc. This enables the automatic execution of an embroidery forming operation on the flat cloth held by the flat flame 11 or the cylindrical cloth held by the cylindrical frame 16.

Next, the operation and effect of the embroidery sewing machine with the above given configuration is explained. As given above, the embroidery sewing machine 1 is capable of executing the embroidery forming operation by selectively attaching the flat frame 11 holding flat cloth or the cylindrical frame 16 holding the cylindrical cloth.

In case the operator desires to form embroidery on flat cloth, the attachments 15 and 14 are to be inserted into the frame holding members 46 and 55 of the flat frame attachment mechanisms 45 and 55 after setting the flat cloth to the flat frame 11. This will attach the flat frame 11 to the flat frame attachment mechanisms 45 and 55 and in turn is connected to the X direction carriage 30. On the other hand, if the operator desires to form embroidery on cylindrical cloth, again as given above, the cylindrical connection part 16a is to be attached onto the cylindrical frame attachment 65a of the cylindrical frame drive unit 65 after setting the cylindrical cloth onto the cylindrical frame 16. This connects the cylindrical frame to the cylinder drive unit 65.

As given above, the operator is to prepare for embroidery sewing by attaching either one of the flat frame 11 or the cylindrical frame 16 on the embroidery machine 1. Further, the sewing operation is started after performing a selection operation of embroidery patterns. Consequently, based on the embroidery data corresponding to the selected embroidery pattern, the sewing machine motor, Y direction drive motor, carriage drive motor 42 etc., are controlled by the control unit and the embroidery forming operation is executed.

At this time, when the Y direction carriage 21 is moved in the Y direction by the Y direction drive motor, both the X direction carriage 30 and cylindrical frame drive unit 65 provided on the Y direction carriage 21 is moved in the Y direction. Therefore, regardless of which of the flat frame 11 or the cylindrical frame 16 is attached, the distance of movement in the Y direction are the same.

Further, when the carriage motor 42 is driven based on the embroidery data, the X direction carriage 30 is moved to the X direction. Along with this, the movement of the X direction carriage 30 is transmitted to the cylindrical frame drive unit 65 via the rack-and-pinion mechanism 75, and the cylindrical frame drive unit is 65 is rotationally driven. At this time, in case the flat frame 11 is connected to the X direction carriage 30, the flat frame 11 moves in the X direction. Otherwise, in case the cylindrical frame is connected to the cylindrical frame drive unit 65, the cylindrical frame 16 is rotationally driven about the axis extending in the Y direction.

Now, since the reference pitch diameter D0 of the pinion 67 and the outer perimeter D1 of the cloth stretching surface 16f of the cylindrical frame is nearly equal, the distance of X direction movement of the flat frame by the X direction carriage 30 and the distance of the rotational drive of the cylindrical frame 16 (cylindrical cloth) of the cylinder drive unit 65 are nearly equal. Since the amount of movement between the flat cloth and the cylindrical cloth are nearly the same, the same embroidery can be formed on both flat cloth and cylindrical cloth using the type of embroidery data when the flat frame 11 or the cylindrical frame is used. That is, the embroidery data for flat frame and cylindrical frame can be shared.

However, as the forming of embroidery patterns proceeds, the process cloth tightly held in the embroidery frame may shrink due to the pull of the seams formed. When such shrinking of the cloth occurs, the formed embroidery becomes slightly smaller than the prescribed size. Also, such shrinking of the cloth becomes more eminent on the cylindrical frame 16 than the flat frame 11 due to the increased difficulty in holding the cloth when using the cylindrical frame.

In this embodiment, since the reference pitch diameter D0 of the pinion 67 is set to be slightly smaller than the outer diameter D1 of the cloth stretching surface 16f of the cylindrical frame, the distance of the rotational drive of the cloth stretching surface 16f of the cylindrical frame 16 is slightly larger than the distance of movement to the X direction of the flat frame. Because of this, even in cases where the above shrinking of the cloth occurs by using the cylindrical frame 16, the negative effects of the cloth shrinking is minimized and the forming of embroidery nearly equaling the size created by the flat frame 11 becomes possible.

Now, in the above given configuration, the drive force of the carriage drive motor 42 is transmitted to both X direction carriage 30 and cylindrical frame drive unit 65, however, since the weight of the X direction carriage 30 (the flat frame) is larger, it is affected by greater inertia, requiring greater torque compared with the cylindrical drive unit 65 (cylindrical frame 16).

In this embodiment, it is configured so that the driving force of the carriage drive motor 42 is first transmitted to the X direction carriage, and the driving force of the X direction carriage 30 in turn is transmitted to the cylindrical frame drive unit 65 via the rack-and-pinion mechanism 75. Therefore, it is possible to drive the flat frame 11 requiring greater inertia in prior to the relatively light-weighted cylindrical frame 16 and prevent the negative effects of the inertia from affecting the cylindrical frame 16. Also, by transmitting the driving power of the carriage drive motor 42 to the cylindrical frame drive unit 65 first, the transmission efficiency of the drive power can be improved as compared with the configuration where the transmission is made to the X direction carriage 30 via the rack-and-pinion mechanism 75 and forms a mechanical advantage.

Also, the cylindrical attachment 65 and the cylindrical frame 16 are moved and driven to the Y direction in a floating state with spaces reserved on the outer periphery of the cylinder bed 4, however, regarding the cylinder bed 4, there is a need to configure it as thick as possible to obtain rigidity.

On the other hand, in order to hold relatively small (thin) cylindrical cloth (for example, shirt sleeves or pockets, etc.), there is a need to make the diameter of the cylindrical frame attachment 65 and the cylindrical frame 16 as small as possible.

In the embodiment, the sewing machine is configured so that the cylindrical frame 16 is connected to the cylindrical attachment 65a of the cylindrical frame 16 so as to be fitted with the outer periphery of the attachment 65a, so the space between the cylinder bed part 4 and the cylinder attachment 65a can be reduced to a minimum extent, and the thickness of the cylinder bed 4 can be increased to the maximum extent as well as reducing the diameter of the frame attachment part 65a to the maximum extent.

Further, the cylindrical frame 16 including the cylindrical connection 16a is made integrally from synthetic resin, and the cylindrical frame drive unit 65 is also made from synthetic resin. Consequently, the weight and cost reduction of the cylindrical frame 16 and cylindrical frame drive unit 65 can be achieved. The location convexity part 65b and the location concavity part 16h constituting the positioning fitting part are formed on the cylindrical frame attachment 65a and cylindrical connection 16a both determining the relative positions in the rotational directions. Consequently, the relative positions of the cylindrical frame 16 and cylindrical frame drive unit 65 can easily be determined. Along with this, the displacement of the cylindrical frame 16 against the cylindrical frame drive unit 65 can reliably be prevented, and the precision of the rotational location of the cylindrical frame 16 can be improved.

Next, modified forms of the above embodiment will be explained hereunder.

It is also possible to rotationally drive the cylindrical frame drive unit 65 by the carriage drive motor 42 first, and transmit the drive force to the X direction carriage via the rack-and-pinion mechanism. In this case, it is enough to transmit the rotational drive of the carriage drive motor 42 as a rotational drive of the cylindrical frame drive unit 65 and a mechanism to convert the rotational drive of a motor to a linear drive, (such as a pulley or a belt) is not required. This simplifies the configuration of the drive mechanism.

Instead of applying a basic gear in which a gear cutting pitch line and a reference pitch line are matched for the pinion 67 of the rack-and-pinion mechanism, a shift gear as indicated in FIG. 10 can be applied. By applying the positive shift gear 67a with the reference pitch line Ps of the gear cutting tool shifted only xm outwards in the radial direction from the basic pitch circle of the basic pinion, a gear tooth thickness will become larger, enabling the reduction of the backlash of the rack member, and the precision of the rotational location can be improved.

The foregoing description and drawings are merely illustrative of the principles of the present invention and are not to be construed in a limiting sense. Various changes and modifications will become apparent to those of ordinary skill in the art. All such changes and modifications are seen to fall within the scope of the invention as defined by the appended claims.

Embroidery sewing machine

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