US20130186317A1

US20130186317A1 - Workpiece Holding Frame

Info

Publication number: US20130186317A1
Application number: US13/747,180
Authority: US
Inventors: Terutada Kojima; Tomoki Hashimoto
Original assignee: Tokai Kogyo Sewing Machine Co Ltd
Current assignee: Tokai Kogyo Sewing Machine Co Ltd
Priority date: 2012-01-24
Filing date: 2013-01-22
Publication date: 2013-07-25
Also published as: DE102013001048A1; JP2013151764A; KR20130086322A; CN203174335U

Abstract

A holding frame includes upper and lower frame members having substantially the same thicknesses, and an inner frame member detachably attachable to the inner peripheries of the upper and lower frame members. The upper and lower frame members are fixed together in vertically superposed relation to each other with a workpiece sandwiched therebetween. The workpiece can be set on the frame in any desired of a first stretched-taut state where the workpiece is stretched taut and generally flush with the upper surface of the upper frame member by being pressed upward via the inner frame member, and a second stretched-taut state where the workpiece is stretched taut and generally flush with the lower surface of the lower frame member by being pressed downward via the inner frame member. The workpiece can be held on the frame with substantially the same degrees of tautness in the first and second stretched-taut states.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on, and claims priority to, JP PA 2012-012493 filed on 24 Jan. 2012. The disclosure of the priority application, in its entirety, including the drawings, claims, and the specification thereof, is incorporated herein by reference.

BACKGROUND

The present invention relates generally to frames for holding a workpiece, such as a fabric, in a stretched-taut state, and more particular to a workpiece holding frame detachably attachable to both of a printing apparatus for performing printing on a workpiece and an embroidery sewing machine for performing embroidery on the workpiece while keeping the same workpiece held thereon.
Among a wide variety of embroidery products made today are ones having a combination of printed and embroidered patterns. To make such a product having a combination of printed and embroidered patterns, printing of a desired pattern is performed on a fabric (workpiece) by means of a printing apparatus, and then embroidery of a desired pattern is performed on the fabric by means of an embroidery sewing machine. The printing apparatus, which may comprise for example a printer for use with a personal computer or the like, includes a print head movable in an X direction, and a transfer device for moving, in a Y direction, a member, called “platen”, capable of holding a workpiece, such as a T-shirt, in a stretched-taut state. The platen having the workpiece held therein is moved in the Y direction by the transfer device on the basis of image data but also the print head is moved in the X direction, so that desired printing is performed on the workpiece.
The embroidery sewing machine includes a machine head having a sewing needle drivable reciprocatively in a vertical (up-down) direction, and a frame transfer mechanism for moving the embroidery frame in the X and Y directions. The embroidery frame, as conventionally known, includes an outer frame member and an inner frame member, and a workpiece is sandwiched and held stretched taut between the inner peripheral surface of the outer frame member and the outer peripheral surface of the inner frame member. Such an embroidery frame having the workpiece held thereon in a stretched-taut state is set onto the frame transfer mechanism and then moved in the X and Y directions, but also the sewing needle of the machine head is driven in the vertical direction to perform embroidery onto the workpiece.
Namely, a typical example of the conventionally-known technique is arranged in such a manner that, when performing printing on the workpiece, the workpiece is held on the platen of the printing apparatus in a stretched-taut state, and that, when performing embroidery on the workpiece, the workpiece is held on the embroidery frame of the embroidery sewing machine in a stretched-taut state. Namely, with the typical conventionally-known technique, it is necessary to perform operations for attaching and detaching the workpiece to and from the platen and then attaching and detaching the workpiece to and from the embroidery frame. Thus, with the conventionally-known technique, much time and labor would be required, and positional alignment between a print pattern and an embroidery pattern tends to be considerably difficult. Therefore, it has heretofore been contemplated to attach the embroidery frame to the printing apparatus to both of the printing apparatus and the embroidery sewing machine with the workpiece kept held on the embroidery frame. However, generally, the embroidery frame sandwiches the workpiece between the inner peripheral surface of the outer frame member and the outer peripheral surface of the inner frame member, and the workpiece is stretched taut at generally the same height as the lower surfaces of the outer and inner frame members. Thus, if the embroidery frame is attached as-is to the printing apparatus, the print head would be located at a height over the workpiece where it interferes with the inner frame member, i.e. it is interfered with by the inner frame member. Therefore, the print head is allowed to move only within a range where it does not interfere with, or it is not interfered with by, the inner frame member, i.e. within a limited range in the neighborhood of the middle of the frame. In such a case, however, movement of the print head is considerably limited because the print head has a great horizontal width and depth, which would result in a considerably reduced printable range. An improved embroidery frame capable of avoiding such an inconvenience is disclosed in Japanese Patent Application Laid-open No. 2005-36330 (hereinafter referred to as “relevant patent literature”).
In the embroidery frame disclosed in the relevant patent literature, at the time of embroidering, a workpiece is sandwiched between the outer frame member and the inner frame member and stretched taut at generally the same height as the lower surfaces of the outer and inner frame members, as in the aforementioned conventionally-known technique. At the time of printing, on the other hand, an auxiliary frame is inserted from below along the inner peripheral surface of the inner frame member, more specifically into a space defined by the inner peripheral surface of the inner frame member, so that the workpiece is stretched taut at generally the same height as the upper surfaces of the outer and inner frame members. Because the workpiece is stretched taut at generally the same height as the upper surfaces of the outer and inner frame members at the time of printing, the print head does not interfere with the inner frame member, and thus, the printable range would not decrease.
In many of embroidery products comprising a combination of printed and embroidered patterns, embroidery is performed after printing in such a manner that an embroidery is superposed on a part of a printed pattern. The embroidery frame disclosed in the relevant patent literature first holds a workpiece in a stretched-taut state by means of outer and inner frame members. Where printing is to be performed before embroidery, an auxiliary frame member is pressed or inserted from below along the inner periphery of the inner frame member (more specifically, into the space defined by the inner periphery of the inner frame member), and then the workpiece is stretched taut at generally the same height as the upper surfaces of the outer and inner frame members. The embroidery frame placed in that state is set onto a printing apparatus so that printing is performed on the workpiece. After completion of the printing, the embroidery frame is removed from the printing apparatus, and the auxiliary frame member is detached from the embroidery frame. Then, the workpiece is placed in a state where the workpiece is stretched taut at generally the same height as the lower surfaces of the outer and inner frame members. The embroidery frame placed in this state is set onto an embroidery sewing machine so that embroidery is performed on the workpiece.
With the embroidery frame disclosed in the relevant patent literature, where the auxiliary frame member is pressed into the space defined by the inner periphery of the inner frame member, the workpiece can be held stretched with increased tightness or tautness. Thus, when embroidery is to be performed subsequently after removal of the auxiliary frame member, the tautness of the workpiece would slack, producing unwanted slackness or looseness in the workpiece. As a consequence, quality of an embroidery made in the aforementioned manner would deteriorate.

SUMMARY OF THE INVENTION

In view of the foregoing prior art problems, it is an object of the present invention to provide an improved workpiece holding frame which can effectively prevent or minimize slackness of a workpiece regardless of whether the workpiece is stretched taut in alignment with the upper surface of the frame or in alignment with the lower surface of the frame.
In order to accomplish the above-mentioned object, the present invention provides an improved workpiece holding frame, which comprises: an upper frame member; a lower frame member having generally a same thickness as the upper frame member; a fixing member for mutually fixing the upper frame member and the lower frame member vertically superposed on each other with a workpiece sandwiched therebetween; and an inner frame member detachably attachable to the inner peripheries of the upper frame member and the lower frame member, the workpiece holding frame being capable of setting thereon the workpiece in any desired one of a first stretched-taut state where the workpiece is stretched taut and generally flush with the upper surface of the upper frame member by being pressed upward via the inner frame member, and a second stretched-taut state where the workpiece is stretched taut and generally flush with the lower surface of the lower frame member by being pressed downward via the inner frame member.
Because the workpiece is sandwiched between the upper and lower frame members having generally the same thicknesses, a degree of tautness of the workpiece in the first stretched-taut state where the workpiece is stretched taut and generally flush with the upper surface of the upper frame member by being pressed upward via the inner frame member and a degree of tautness of the workpiece in the second stretched-taut state where the workpiece is stretched taut and generally flush with the lower surface of the lower frame member by being pressed downward via the inner frame member are substantially equal to each other. If the inner frame member is not attached as above, the workpiece sandwiched between the upper and lower frame members would be stretched taut and flat at the height of the boundary (middle position) between the upper and lower frame members. However, if the inner frame member is attached as above, the workpiece is pressed upward via the inner frame member by a first displacement amount or distance from the middle position into the first stretched-taut state in one operation, or the workpiece is pressed downward by a second displacement distance from the middle position into the second stretched-taut state in another operation. Because the first displacement amount or distance and the second displacement amount or distance are substantially equal, the degree of tautness in the first stretched-taut state and the degree of tautness in the second stretched-taut state are substantially equal to each other. In this way, the present invention can eliminate or minimize the possibility of unwanted slackness or distortion being produced in both of a case where printing is performed on the workpiece in the first stretched-taut state and a case where embroidery is performed on the workpiece in the second stretched-taut state. The workpiece can be held on the frame with substantially the same degrees of tautness in the first and second stretched-taut states in the aforementioned manner, so that no unwanted slackness would be produced in the workpiece even where switched between the first and second stretched-taut states.
Thus, in the case where embroidery is performed on the workpiece in the second stretched-taut state, the present invention can avoid the inconvenience of deteriorated embroidering quality due to insufficient workpiece-stretching force. Similarly, in the case where printing is performed on the workpiece in the first stretched-taut state, the present invention can avoid the inconvenience of deteriorated printing quality due to insufficient workpiece-stretching force. Further, because, in the case where printing is performed on the workpiece in the first stretched-taut state, the workpiece is stretched taut at generally the same height as the upper surface of the upper frame member, the holding frame would not interfere with the print head during the printing, so that the present invention can prevent a printable range of the print head from undesirably decreasing.
The following will describe embodiments of the present invention, but it should be appreciated that the present invention is not limited to the described embodiments and various modifications of the invention are possible without departing from the basic principles. The scope of the present invention is therefore to be determined solely by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain preferred embodiments of the present invention will hereinafter be described in detail, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of an embodiment of a workpiece holding frame of the present invention;

FIG. 2 is a plan view of the holding frame;

FIG. 3 is an enlarged sectional plan view of the holding frame showing an example construction for fixing an inner frame member to the inner periphery of an upper frame member;

FIG. 4 is an enlarged sectional side view showing the example construction for fixing the inner frame member to the upper frame member;

FIG. 5 is an enlarged sectional side view showing an example construction for fixing the inner frame member to a lower frame member;

FIG. 6 is a sectional front view showing a workpiece introduced between the upper frame member and the lower frame member with the inner frame member fixed to the lower frame member;

FIG. 7 is a sectional front view showing the workpiece held in a first stretched-taut state where the workpiece is stretched taut by being sandwiched between the upper and lower frame members and then pressed upward via the inner frame member from the state of FIG. 6 in such a manner as to lie generally flush with the upper surface of the upper frame member;

FIG. 8 is a sectional front view showing the inner frame member positioned above the upper frame member with the workpiece sandwiched between the upper and lower frame members;

FIG. 9 is a sectional front view showing the workpiece held in a second stretched-taut state where the workpiece is stretched taut by being pressed downward via the inner frame member from the state of FIG. 8 in such a manner as to lie generally flush with the lower surface of the lower frame member;

FIG. 10 is a perspective view of a printing apparatus to which the embodiment of the holding frame can be applied;

FIG. 11 is a perspective view illustrating relationship among a support base of the printing apparatus, a platen of the printing apparatus and the holding frame; and

FIG. 12 shows a single-head type embroidery sewing machine to which the preferred embodiment of the holding frame is applied.

DETAILED DESCRIPTION

FIG. 1 is an exploded perspective view of an embodiment of a workpiece holding frame S of the present invention. In the figure, the workpiece holding frame S includes upper and lower frame members 1 and 2 that are annular in shape and have generally the same thicknesses, and an inner frame member 3 having a thickness generally equal to a total thickness of the upper and lower frame members 1 and 2 when vertically superposed, face to face, on each other. Holding plates 4 and 5 for setting the holding frame S onto an embroidery sewing machine are fixed to respective generally middle portions of left and right sides of the upper frame member 1. A block 6 having a through-hole 6 a formed therein is fixed to an upper portion of each of four corner sections of the upper frame member 1. Further, a plurality of circular recessed portions are formed in the upper surface of the upper frame member 1, and a magnet 7 is fitted in each of the circular recessed portions. Furthermore, left and right covers 8 and 9, which are separate left and right members, are disposed on the upper surface of the frame member 1 so as to prevent the magnets 7 from accidentally getting out of the recessed portions.
Further, a block 10 having a through-hole 10 a formed therein is fixed to a lower portion of each of four corner sections of the lower frame member 2. A plurality of recessed portions are formed in the lower surface of the lower frame member 2, and a magnet 11 is fitted in each of the recessed portions. Furthermore, left and right covers 12 and 13, which are separate left and right members, are disposed on the lower surface of the lower frame member 2 so as to prevent the magnets 11 from accidentally getting out of the recessed portions. An elongated guide member 14 is fixed to and projects from the upper surface of each of front and rear sides of the lower frame member 2, and two short-length guide members 15 are fixed, in a vertical row, to the upper surface of each of left and right sides of the lower frame member 2 and project from the upper surface of each of left and right sides of the lower frame member 2. Furthermore, engaging grooves 16 each for engaging with the corresponding guide member 14 are formed in the lower surface of the front and rear sides of the upper frame member 1, and engaging grooves 17 each for engaging with the corresponding guide member 15 are formed in the lower surface of the left and right sides of the upper frame member 1.
As the upper and lower frame members 1 and 2 are vertically superposed on each other, the upper and lower frame members 1 and 2 adhere to each other by the magnetic force of the magnets 7 and 11 so that a workpiece is sandwiched between the upper and lower frame members 1 and 2. At that time, respective superposed positions of the upper and lower frame members 1 and 2 are determined automatically through engagement between the guide members 14, 15 of the lower frame member 2 and the engaging grooves 16 and 17 of the upper frame member 1. Namely, in the illustrated example, the magnets 7 and the magnets 11 function as fixing members for mutually fixing the upper and lower frame members 1 and 2 by the magnetic force. Note that one of the mutually-adhering magnets 7 and 11 may be replaced with a ferromagnetic substance, such as iron.
The inner frame member 3 has its outer periphery slightly smaller in size than the inner periphery of each of the upper frame member 1 and the lower frame member 2. The inner frame member 3 have protruding portions 18 formed on upper portions of its four corner sections and having generally the same size as the inner periphery of each of the upper and lower frame members 1 and 2. Furthermore, a block 19 having a through-hole 19 a formed therein is fixed to each of the upper portions of the four corner sections of the inner frame member 3. Such an inner frame member 3 is inserted into a space defined by the inner peripheries of the upper and lower frame members 1 and 2 to hold a workpiece in a stretched taut state.
In an embroidering operation, the inner frame member 3 is inserted into the space defined by the inner peripheries of the upper and lower frame members 1 and 2 from above (i.e., above the upper frame member 1) and then fixed to the upper frame member 1. To fix the inner frame member 3 to the upper frame member 1, the through-holes 19 a formed in the blocks 19 of the inner frame member 3 are positioned in alignment with the through-holes 6 a formed in the blocks 6 of the upper frame member 1. Then, fastening pins 20 are inserted from outside through the respective through-holes 6 a of the blocks 6 of the upper frame member 1 so that the distal ends of the fastening pins 20 are inserted into the through-holes 19 a of the blocks 19 of the inner frame member 3. FIG. 3 is a sectional plan view showing in enlarged scale the blocks 6 and 19 etc. to illustrate a construction for fixing the inner frame member 3 to the upper frame member 1. As clear from FIG. 3, a ball plunger 21 is provided laterally to the axis of the through-hole 6 a of the block 6 of the upper frame member 1. The fastening pin 20 has grooves 20 a and 20 b formed in its substantially-middle portion and distal end portion for engagement with a ball provided at the distal end of the ball plunger 21. By engaging the substantially-middle groove portion 20 a with the ball of the ball plunger 21, each of the fastening pins 20 is held in a position where its distal end portion is inserted in the through-hole 19 a of the block 19 of the inner frame member 3, so that the inner frame member 3 is attached to the upper frame member 1. FIG. 4 is a sectional side view of the blocks 6 and 19 in the state where the inner frame member 3 is attached to the upper frame member 1, where “H” represents a workpiece (fabric). In the state of FIG. 4 (i.e., hereinafter referred to as “second stretched-taut state”), as will be later described, the workpiece H pressed downward by the lower surface of the inner frame member 3 lies in substantially the same plane with the lower surface of the lower frame member 2, i.e. lies substantially flush with the lower surface of the lower frame member 2. In this case, a combination of the fastening pin 20 and the through- holes 6 a and 19 a constitute a member for fixing the inner frame member 3 to the upper frame member 1.
Further, by engaging the groove 20 b, formed in the distal end portion of the fastening pin 20, with the ball of the ball plunger 21, the fastening pin 20 is held in a position where its distal end portion is fitted in the through-hole 6 a of the block 6 of the upper frame member 1; in this state, the inner frame member 3 can be taken out of the space defined by the inner peripheries of the upper and lower frame members 1 and 2 and then again inserted into the space as desired. Note, however, that the groove 20 b in the distal end portion of the fastening pin 20 is not necessary essential.
In a printing operation, on the other hand, an up-down (vertical) orientation of the inner frame member 3 is reversed from that in the embroidering operation, and then, the inner frame member 3 thus reversed in up-down orientation is inserted into the space defined by the inner peripheries of the upper and lower frame members 1 and 2 from below (i.e., below the lower frame member 2) and fixed to the lower frame member 2. To fix the inner frame member 3 to the lower frame member 2, the through-holes 19 a formed in the blocks 19 of the inner frame member 3 are positioned in alignment with the through-holes 10 a formed in the blocks 10 of the lower frame member 2. Then, the fastening pins 20 are inserted from outside through the respective through-holes 10 a of the blocks 10 of the lower frame member 2 so that the distal ends of the fastening pins 20 are inserted into the through-holes 19 a of the blocks 19 of the inner frame member 3. Each of the blocks 10 of the lower frame member 2 also has a ball plunger 21, like the blocks 6 of the upper frame member 1. By engaging the substantially-middle groove portion 20 a with the ball of the ball plunger 21, each of the fastening pins 20 is held in a position where its distal end portion is inserted in the through-hole 19 a of the block 19 of the inner frame member 3, so that the inner frame member 3 is attached to the lower frame member 2. FIG. 5 is a sectional side view of the blocks 10 and 19 in the state where the inner frame member 3 is attached to the lower frame member 2. In the state of FIG. 5 (i.e., hereinafter referred to as “first stretched-taut state”), as will be later described, the workpiece H pressed upward by the upper surface of the upper frame member 3 lies in substantially the same plane with the upper surface of the upper frame member 1, i.e. lies substantially flush with the upper surface of the upper frame member 1. In this case, a combination of the fastening pin 20 and the through- holes 10 a and 19 a constitute a member for fixing the inner frame member 3 to the lower frame member 2.
Next, a description will be given about a manner in which the workpiece H is held on the holding frame S in a stretched-taut state, assuming that the printing operation is first performed on the workpiece H followed by the embroidering operation.
As shown in FIG. 6, the inner frame member 3 is inserted into the space defined by the inner periphery of the lower frame member 2 and attached to the lower frame member 2 by means of the fastening pins 20 in advance. Then, the workpiece H is placed on the lower frame member 2 and the inner frame member 3, and the upper frame member 1 is vertically superposed on the lower frame member 2 from above the workpiece H. Thus, the upper frame member 1 and the lower frame member 2 are adhered to each other by the magnetic force of their respective magnets 7 and 11 so that the workpiece H is sandwiched therebetween. Because the inner frame member 3 projects upward above the lower frame member 2 by an amount generally equal to the thickness of the upper frame member 1, the workpiece H is pressed upward by the upper surface of the inner frame member 3 so that it is stretched taut at generally the same height as the upper surface of the upper frame member 1, i.e. in generally the same plane as the upper surface of the upper frame member 1, as shown in FIG. 7; namely, the workpiece H is stretched taut and substantially flush with the upper surface of the upper frame member 1, and such a state is the first stretched-taut state. Whereas the inner frame member 3 has been described above as attached to the lower frame member 2 in advance, the present invention is not so limited. For example, the inner frame member 3 may be inserted from below the lower frame member 2 into the space defined by the inner peripheries of the upper frame member 1 and the lower frame member 2 and then attached to the lower frame member 2 after the workpiece H is sandwiched between the upper frame member 1 and the lower frame member 2. Then, the holding frame S having the workpiece H held thereon in the first stretched-taut state as shown in FIG. 7 is set onto the printing apparatus.
FIG. 10 shows the printing apparatus, which includes a print head 22 movable in an X direction and a transfer plate 23 for moving the workpiece H in a Y direction. A support base 24 is provided on the upper surface of the transfer plate 23 by being magnetically adhered to the transfer plate 23, and a platen 25 for retaining the holding frame S is detachably attached to the support base 24. FIG. 11 is a perspective view showing the support base 24, platen 25 and holding frame S. Support blocks 26 and 27 are fixed to front and rear end portions, respectively, of the support base 24. The support blocks 26 and 27 have recessed portions 26 a and 27 a formed in their respective upper surfaces. The platen 25 has front and rear engaging arms 28 and 29 formed on its front and rear end portions, respectively, for engagement with the recessed portions 26 a and 27 a of the support blocks 26 and 27. A leaf spring 29 for resiliently pressing against the upper surface of a distal end portion of the platen's engaging arm 28 engaging with the recessed portion 26 a of the front support block 26 is fixed to the front surface of the front support block 26. Similarly, a leaf spring 31 for resiliently pressing against the upper surface of the platen's engaging arm 29 engaging with the recessed portion 27 a of the rear support block 27 is fixed to the upper surface of the rear support block 27. The platen 25 includes a support section 32 for supporting the holding frame S, and a guide projection 33 for positioning the holding frame S by fitting in a space defined by the inner periphery of the inner frame member 3. The guide projection 33 has a height such that its upper surface contacts the workpiece H, held on the holding frame S in the stretched-taut state, when the holding frame S is set on the platen 25, so that the upper surface of the guide projection 33 supports the lower surface of a portion of the workpiece H to be printed on.
To set the holding frame S onto the platen 25, the platen 25 is detached from the support base 24, and then the holding frame S is fitted over the outer periphery of the guide projection 33 of the platen 25 so that it is supported on the support section 32. If the workpiece H is a generally-bag-shaped workpiece, such as a T shirt, an underside (back-surface side) portion, which is not held in the stretched-taut state, of the workpiece H may be positioned underneath the platen 25 at that time. After the holding frame S is set onto the platen 25, the platen 25 is attached to the support base 24. Note that the holding frame S may be set onto the platen 25 with the support base 24 detached from the transfer plate 23.
After the holding frame S is set onto the printing apparatus in the aforementioned manner, the workpiece H is moved in the Y direction via the feeding plate 23 on the basis of image data of a desired pattern to be printed onto the workpiece H, but also the print head 22 is moved in the X direction to print the desired pattern onto the workpiece H. After completion of the printing, the holding frame S is detached from the printing apparatus.
Next, the fastening pins 20 inserted in the four corners of the lower frame member 2 are pulled out from the four corners, and then the inner frame member 3 is pulled downward away from the lower frame member 2. Then, as shown in FIG. 8, the up-down (vertical) orientation of the inner frame member 3 is reversed from that in the printing operation and then positioned above the upper frame member 1. After that, the inner frame member 3 is inserted into the upper frame member 1 from above and fixed to the upper frame member 1 by means of the fastening pins 20. Thus, the workpiece H is pressed downward by the lower surface of the inner frame member 3, so that the workpiece H is stretched taut at generally the same height of the lower surface of the lower frame member 2, i.e. in generally the same plane as the lower surface of the lower frame member 2, as shown in FIG. 9; namely, the workpiece H is stretched taut and substantially flush with the lower surface of the lower frame member 2, and such a state is the second stretched-taut state. Then, the holding frame S having the workpiece H held thereon in the second stretched-taut state as shown in FIG. 9 is set onto the embroidery sewing machine.
In FIG. 8, it is shown that some slackness has been produced in the workpiece H by the workpiece H having been stretched in the first stretched-taut state at the previous step. Further, in FIG. 9, it is shown that the above-mentioned slackness is absorbed by the workpiece H having been pressed downward and stretched in the second stretched-taut state, and that the workpiece H is stretched with generally the same degree of tautness as in the first stretched-taut state. The reason why the workpiece H is stretched in the second stretched-taut state with generally the same degree of tautness as in the first stretched-taut state is as follows. Namely, the workpiece H sandwiched between the upper and lower frame members 1 and 2, having generally the same thicknesses, would be stretched taut and flat at the height of the boundary (middle position) between the upper and lower frame members 1 and 2, if the inner frame member 3 is not inserted and attached. However, if the inner frame member 3 is inserted and attached as above, the workpiece H is pressed upward by a first displacement amount or distance from the middle position into the first stretched-taut state in the printing operation, while the workpiece H is pressed downward by a second displacement distance from the middle position into the second stretched-taut state in the embroidering operation. Because the first displacement amount or distance and the second displacement amount or distance are substantially equal to each other, the degree of tautness in the first stretched-taut state and the degree of tautness in the second stretched-taut state are substantially equal to each other.
FIG. 12 shows a single-head type embroidery sewing machine to which the preferred embodiment of the holding frame S is applied. This single-head type embroidery sewing machine includes: a machine head 34 having a sewing needle drivable vertically (in the up-down direction) in a reciprocative fashion; a cylinder head 35 having a rotationally-drivable rotary hook, and a pair of holding bases 36 and 37 to which the holding frame S is attachable and which is drivable in the X and Y directions.
To set the holding frame S onto the embroidery sewing machine, the holding plates 4 and 5 are inserted into respective distal end portions of the pair of holding bases 36 and 37, so that the holding frame S is held on the pair of holding bases 36 and 37. After the holding frame 35 is set as above, desired sewing is performed on the workpiece S in the well-known manner by not only the sewing needle of the machine head 34 being vertically driven but also the rotary hook of the cylinder head 35 being rotationally driven. Also, at that time, the holding frame S is moved in the X and Y directions together with the pair of holding bases 36 and 37 to perform embroidery on the workpiece H based on embroidery data. After completion of the embroidery, the holding frame S is detached from the embroidery sewing machine, and then the workpiece H is removed from the holding frame S.
According to the above-described workpiece holding frame S of the present invention, the workpiece H is stretched taut at generally the same height as the upper surface of the upper frame member 1 in the printing operation, while the workpiece H is stretched taut at generally the same height as the lower surface of the lower frame member 2 in the embroidering operation. Thus, the holding frame S would not interfere with the print head 22 during the printing operation, so that the printable range can be prevented from decreasing.
Further, because the upper and lower frame members 1 and 2 have generally the same thicknesses and because the workpiece H is stretched taut by being pressed by generally the same displacement distances via the inner frame member 3 from the boundary (middle position) between the upper and lower frame members 1 and 2 to the upper surface of the upper frame member 1 and from the boundary to the lower surface of the lower frame member 2 at the time of the printing operation and the embroidering operation. Thus, the workpiece H can be stretched with generally the same degrees of tautness in the printing operation and in the embroidering operation. In this way, the preferred embodiment of the holding frame can prevent the tautness of the workpiece H from undesirably decreasing in one of the printing operation and the embroidering operation, and thus, it can prevent the workpiece H from slackening and thereby prevent deterioration of the printing or embroidering quality due to slackness produced in the workpiece H.
It should be appreciated that the above-described embodiment of the holding frame S is just illustrative and may be of any of various desired shapes and sizes. Namely, the holding frame S may be constructed in any desired shape and size depending on the type of the workpiece and designs (sizes etc.) of the printing and embroidery. Further, the guide projection 33 of the platen 25 of the printing apparatus may be constructed in any desired manner corresponding to the shape and size of the holding frame S used.
Furthermore, whereas the embodiment of the present invention has been described above in relation to the case where the inner frame member 3 is fixed to the upper frame member 1 or lower frame member 2 by means of the fastening pins 20, the construction for fixing the inner frame member 3 to the upper frame member 1 or lower frame member 2 is not so limited. For example, a ball plunger may be provided in the inner frame member 3 and recessed portions engageable with the ball of the ball plunger provided in the inner frame member 3 may be formed in the upper and lower frame members 1 and 2 so that the inner frame member 3 can be attached by the ball of the ball plunger engaging with the recessed portion. Further, any other desired fastening means or construction comprising screws, clips, springs, etc. rather than the pins 20 may be employed. Alternatively, the inner frame member 3 may be half-fixed to the upper or lower frame member 1 or 2 by being press-fitted into the upper or lower frame member 1 or 2. In short, it is only necessary that the inner frame member 3 be detachably attached to the inner periphery of the upper or lower frame member 1 or 2.
Further, the member or construction for mutually fixing the upper and lower frame members 1 and 2 is not limited to the one using magnetic force as in the above-described embodiment, and any other member or construction comprising screws, clips, springs, etc. may be employed.

Claims

1. A workpiece holding frame comprising:

an upper frame member;

a lower frame member having generally a same thickness as said upper frame member;

a fixing member for mutually fixing said upper frame member and said lower frame member vertically superposed on each other with a workpiece sandwiched therebetween; and

an inner frame member detachably attachable to inner peripheries of said upper frame member and said lower frame member,

said workpiece holding frame being capable of setting thereon the workpiece in any desired one of a first stretched-taut state where the workpiece is stretched taut and generally flush with an upper surface of said upper frame member by being pressed upward via said inner frame member, and a second stretched-taut state where the workpiece is stretched taut and generally flush with a lower surface of said lower frame member by being pressed downward via said inner frame member.

2. The workpiece holding frame as claimed in claim 1, wherein said fixing member is constructed to mutually fix said upper frame member and said lower frame member by magnetic force.

3. The workpiece holding frame as claimed in claim 1, which further comprises a member for fixing said inner frame member to at least one of said upper frame member and said lower frame member.