THREAD SPOOL STAND DEVICE AND SEWING MACHINE PROVIDED WITH THREAD SPOOL STAND DEVICE

Abstract

A thread spool stand device is disclosed. The thread spool stand device includes a thread spool base and a thread spool pin that has a base end thereof secured to the thread spool base and that allows attachment of a thread spool. The thread spool stand device further includes a positioning mechanism that determines position of attachment of the thread spool relative to the thread spool pin. The positioning mechanism includes a contact section that contacts an inner peripheral surface of a core of the thread spool. The contact section is radially movable responsive to variation in an inner diameter of the core such that the contact section expands radially outward or contracts radially inward to be equally spaced from an axial center of the thread spool pin.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application 2010-158689, filed on Jul. 13, 2010, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a thread spool stand device provided with spool pins for attachment of thread spools. The present disclosure further relates to a sewing machine provided with such thread spool stand device.

BACKGROUND

Sewing machines are known that are provided with a thread spool stand having a plurality of thread spool pins. The thread spool pins are made of thin bars that extend upward. A thread spool is made of a generally cylindrical core which may or may not be tapered that has thread wound on it. Thus, the thread spool exhibits a tapered or a cylindrical profile. The cylindrical core is hollow and has a vertically penetrating central through hole. The thread spool is attached to the thread spool stand device so as to pass the thread spool pin through the central through hole of the core. The thread drawn from the thread spool attached to the threads spool pin is guided by a thread guide mechanism located above the thread spool and is ultimately supplied to the sewing needle by way of components such as a thread tension regulator and thread take-up. In order to keep the tension of thread drawn from the thread spool constant or in order to prevent physical contact between the neighboring thread spools, the thread spool is preferably located such that axial center of the thread spool and the axial center of the thread spool pin are coincident when the thread spool is attached to the thread spool stand device.

Given such background, a configuration for attaching a thread spool is known that has a plurality of leaf springs provided on the outer periphery of the thread spool pin such that the elasticity of the leaf springs are exerted on the inner peripheral surface of the typically cylindrical core of the thread spool. Further, an umbrella member configured by a plurality of elastically deformable vanes is provided around the outer periphery of the thread spool pin. The above described configuration may provide one solution for locating the thread spool substantially at axial center of the thread spool pin.

However, the above described configuration of imparting the elasticity of the leaf springs and the vanes disposed circumferentially on the inner peripheral surface of the cylindrical core may fail to produce equal distributions of elasticity due to unequal amount of elastic deformation of the circumferentially disposed leaf springs and vanes which typically originates from dimension variation of the parts used. Failure to obtain equalized elastic deformation of the leaf springs and vanes may cause the axial center of the thread spool to be displaced from the axial center of the thread spool pin. Further, because leaf springs and vanes only provide small range of elastic deformation, not enough elasticity is produced when handling sizeable thread spools that have larger cylindrical cores with larger inner diameters. Such size factors may also cause displacement problems as well.

As described above, the conventional configuration also lacks in the capacity to accommodate thread spools ranging in size and dimensions of the inner diameters of cores.

SUMMARY

One object of the present disclosure is to provide a thread spool stand device that allows attachment of a thread spool such that the axial center of the thread spool is coincident with the axial center of a thread spool pin and that is capable of accommodating thread spools of various sizes. Another object of the present disclosure is to provide a sewing machine provided with such thread spool stand device.

In aspect, a thread spool stand device is disclosed. The thread spool stand device includes a thread spool base and a thread spool pin that has a base end thereof secured to the thread spool base and that allows attachment of a thread spool. The thread spool stand device also includes a positioning mechanism that determines position of attachment of the thread spool relative to the thread spool pin. The positioning mechanism includes a contact section that contacts an inner peripheral surface of a core of the thread spool. The contact section is radially movable responsive to variation in an inner diameter of the core such that the contact section expands radially outward or contracts radially inward to be equally spaced from an axial center of the thread spool pin.

Other objects, features and advantages of the present disclosure will become clear upon reviewing the following description of the illustrative aspects with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view generally depicting a sewing machine according to a first exemplary embodiment of the present disclosure;

FIG. 2 is a partial perspective view of a thread spool stand device;

FIGS. 3A to 3D are plan, front, side, and bottom views of a thread spool pin and a positioning mechanism;

FIGS. 4A to 4E are plan, front, side, and bottom views of a link base;

FIGS. 5A to 5E are plan, front, side, and bottom views of an upper link element;

FIGS. 6A to 6E are plan, front, side, and bottom views of a lower link element;

FIGS. 7A to 7E are plan, front, side, and bottom views of a slider;

FIGS. 8A and 8B are front and side views of a link shaft;

FIGS. 9A to 9C illustrate how a thread spool is attached to the thread spool pin;

FIGS. 10A to 10C correspond to FIGS. 9A to 9C;

FIGS. 11A and 11B are front views of the thread spool pin and the positioning mechanism according to a second exemplary embodiment of the present disclosure; and

FIG. 12 is a front view of the thread spool stand device according to a modified exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

A first exemplary embodiment of the present disclosure will be described with reference to FIGS. 1 to 10 through application to a multi-needle embroidery sewing machine hereinafter represented as multi-needle sewing machine M. It is to be noted that as viewed in FIG. 1, the direction in which the user positions him/herself relative to multi-needle sewing machine M is the forward direction and the opposing direction, naturally, is the rear direction.

Referring to FIG. 1, multi-needle sewing machine M is primarily configured by a pair of left and right feet 1, pillar 2, arm 3, cylinder bed 4, and needle-bar case 5. Pillar 2 stands substantially upright from the rear end of feet 1. From the upper portion of pillar 2, arm 3 extends forward so as to oppose cylinder bed 4 extending forward from the lower end of pillar 2. Needle-bar case 5 is attached on the front face of arm 3. Feet 1, pillar 2, arm 3, and cylinder bed 4 are structurally integral and are collectively represented as sewing machine body 6. Sewing machine body 6 is typically provided with components such as a controller not shown that is responsible for controlling multi-needle sewing machine M and control panel 7.

On the front face of control panel 7, a vertically long liquid crystal display (LCD) 7a and various switches such as start/stop switch 7b are provided for user operation. On the sidewall of control panel 7, interfaces such as slot 7c is provided to allow insertion of computer readable medium not shown that is capable of storing information such as embroidery data pertaining to various types of embroidery patterns. On the front face of LCD 7a, touch panel 7d including a plurality of touch keys configured by transparent electrodes are provided on the for allowing user operation to execute various functionalities and to make various specifications for parameter settings and thread spool replacement setting, etc.

On the upper surface of cylinder bed 4, needle plate 8 is provided that has needle hole 8a that is representative of a needle drop position of a sewing needle not shown. Above feet 1, carriage 9 oriented in the left and right direction is disposed which contains an X-drive mechanism not shown that drives a frame mount base not shown provided in front of carriage 9 in the X direction or the left and right direction. Within the left and right feet 1, a Y-direction drive mechanism not shown is provided that drives carriage 9 in the Y direction or the front and rear direction. X-direction drive mechanism is driven by an X-axis motor not shown whereas the Y-direction drive mechanism is driven by a Y-axis motor not shown. The workpiece cloth not shown to be embroidered is held by a rectangular embroidery frame not shown which is mounted on the frame mount base. The embroidery frame is driven in the X direction along with the frame mount base by the X-direction drive mechanism, and in the Y direction in synchronism with carriage 9 by the Y-direction drive mechanism. The workpiece cloth is thus, fed in the left and right direction as well as the front and rear direction.

The above described needle-bar case 5 supports ten vertically extending needle bars not shown that are arranged side by side in the left and right direction. Needle bars are allowed to move up and down and each needle bar has a sewing needle not shown attached to its lower end. Needle-bar case 5 is further provided with ten thread take-ups 10a to 10j that are associated with the ten needle bars. Thread take-ups 10a to 10j are also allowed to move up and down and are aligned side by side in the left and right direction. Needle-bar case 5 has a forwardly declining thread tension regulator base 11 on its upper side that merges in continuation with the upper end of needle bar case 5. Thread tension regulator base 11 is provided with ten thread tension regulators 12a to 12j for making adjustments in thread tension. Thread tension regulator base 11 is further provided, at its rear end, ten laterally aligned thread inlets 13a to 13j.

At the front end of arm 3, laterally extending guide rail 3a is provided to provide support to needle-bar case 5 as well as allowing needle-bar case 5 to slide laterally along it. Arm 3 contains a needle-bar case transfer mechanism not shown that transfers needle-bar case 5 in the left and right direction. The needle-bar case transfer mechanism, driven by a drive motor not shown, switches a single pair of needle bar and thread take-up selected from the ten pairs of needle bars and thread take-ups 10a to 10j to the needle drop position. The pair of needle bar and thread take-up (one of 10a to 10j) switched to the needle drop position is driven up and down in synchronism with a sewing machine motor not shown provided at pillar 2. The pair of needle bar and thread take-up work in coordination with a rotary hook not shown provided at the front edge of cylinder bed 4 to form embroidery stitches on the workpiece cloth held by the embroidery frame.

At the upper portion of sewing machine body 6, thread spool stand device 14 is provided which includes support base 15, thread spool bases 16 and 17, threading mechanism 18, and thread guide mechanism 19. Support base 15 is provided on the upper surface of arm 3. Thread spool bases 16 and 17 each carry five thread spools. Threading mechanism 18 is responsible for threading the threads drawn from the thread spools. Thread guide mechanism 19 guides the threads threaded to threading mechanism 18.

Threading mechanism 18 is located above thread spool bases 16 and 17 and is provided with a laterally extending threading member 20. Threading member 20 is located directly above a total of ten thread spool pins later described in detail distributed to thread spool bases 16 and 17. On the front side panel of threading member 20, ten threading holes 21a to 21j are defined, whereas on the rear side panel, six threading holes 22a to 22f are defined to allow passage of threads.

Thread guide mechanism 19 is provided with a laterally extending thread guide member 23. Thread guide member 23 is provided with ten laterally spaced thread-guide insert holes 24a to 24j. Between thread guide member 23 and the aforementioned thread inlets 13a to 13j, a laterally extending mid thread-guide member 25 is provided which is provided with ten laterally spaced mid thread-guide insert holes 26a to 26j. Thread-guide insert holes 24a to 24j and mid thread-guide insert holes 26a to 26j are laterally spaced by equal spacing.

Thread guide member 23, mid thread-guide member 25 and the rear end portion of thread tension regulator base 11 are joined by mid thread-guide link mechanism 27. Mid thread-guide link mechanism 27 includes a pair of first link members 28 and 29 and a pair of second link members 30 and 31. First link members 28 and 29 are responsible for joining thread guide member 23 and mid thread-guide member 25. Second link members 30 and 31 are responsible for joining mid thread-guide member 25 and the rear end portion of thread tension regulator base 11. First link member 28 and second link member 30 are pivotably supported by one another. Similarly, first link member 29 and second link member 31 are pivotably supported by one another. Thus, when needle-bar case 5 is moved from side to side by the needle-bar transfer mechanism, mid thread-guide member 25 follows the side to side movement through the linkage provided by mid thread-guide link mechanism 27.

The threads drawn from the thread spools are ultimately passed through thread inlets 13a to 13j by way of: threading holes 21a to 21j and 22a to 22j of threading member 20, thread-guide insert holes 24a to 24j of thread guide member 23, and mid thread-guide insert holes 26a to 26j of mid thread-guide member 25. The threads passed through thread inlets 13a to 13j are further passed through components such as the aforementioned thread tension regulators 12a to 12j and thread take-ups 10a to 10j to ultimately thread the eye of each sewing needle. The strings of threads maintain a parallel relationship with one another as they pass through thread-guide insert holes 24a to 24j of thread guide member 23, mid thread-guide insert holes 26a to 26j of mid thread-guide member 25, and thread inlets 13a to 13j. Because mid thread-guide member 25 follows the side to side movement of needle-bar case 5 actuated by the needle-bar case transfer mechanism by way of the aforementioned link mechanism 27, thread tangling can be prevented effectively.

Next, a description will be given on thread spool bases 16 and 17. Thread spool bases 16 and 17 are each supported by support base 15 provided at the upper rear portion of arm 3. Thread spool bases 16 and 17 are disposed symmetrically relative to arm 3 in front view. Because thread spool bases 16 and 17 are identical in structure, description will be given hereinafter based on thread spool base 16 with reference to FIG. 2.

Referring to FIG. 2, thread spool base 16 is provided with base 32 which is trapezoidal in plan view. On upper surface 32a of base 32, five disc-shaped mount stages 33 to 37 are provided which are structurally integral with upper surface 32a. Each of mount stages 33 to 37 are provided with LED (Light Emitting Diode) not shown that indicate the color of the thread spool. The color indicated by the LED can be seen through windows 33a to 37a. Five thread spool pins 43 to 47, one for each of mount stages 33 to 37, extend upward from the upper surface centers of mount stages 33 to 37. On the upper surface of each of mount stages 33 to 37, disc-shaped sponges 38 to 42 are provided that have a though hole defined on it to allow insertion of thread spool pins 43 to 47. Sponges 38 to 42 are provided to prevent the thread drawn from the thread spool from being stuck underneath the thread spools.

Each of mount stages 33 to 37 has a through hole not shown defined on their diametric centers through which base ends 43a to 47a of thread spool pins 43 to 47 are inserted whereby thread spool pins 43 to 47 are secured on mount stages 33 to 37. The axial centers of thread spool pins 43 to 47, the diametric centers of mount stages 33 to 37, and the diametric centers of sponges 38 to 42 are coincidental. Further, tips 43b to 47b of thread spool pins 43 to 47, distal from base ends 43a to 47a, are tapered to facilitate insertion of the thread spools.

The five thread spool pins 43 to 47 are positioned such that two are laterally aligned in the front row and three are laterally aligned in the back row. In the first exemplary embodiment, thread spool pins 44 and 46 are aligned in the front row whereas thread spool pins 43, 45 and 47 are aligned in the back row. Each of thread spool pins 43 to 47 are provided with either of positioning mechanisms 48 to 52. Positioning mechanisms 48 to 52 are mechanically attached to thread spool pins 43 and 47 and are all identical in structure. In the following description, positioning mechanism 48 attached to thread spool pin 43 will be explained in detail with reference to FIGS. 3A to 8B to describe positioning mechanisms 48 to 52 in general.

As shown in FIGS. 3A to 3D, positioning mechanism 48 is provided with link mechanism 53 and compression spring 54. Compression spring 54 is wound around thread spool pin 43 and is compressed and decompressed as will be later described. On a portion of thread spool pin 43 located above compression spring 54, link mechanism 53 is provided. The upper end of compression spring 54 and the lower end of link mechanism 53, which corresponds to the bottom surface of a later described slider, are placed in contact. Link mechanism 53 includes link base 55, three connection links 56, and slider 57.

Referring to FIGS. 4A to 4E, link base 55 is primarily configured by link base body 58 which is provided with insert hole 59a, three upper link element supports 59b, three notches 59c, and six link shaft holes 59d. Insert hole 59a allows insertion of thread spool pin 43. The three upper link element supports 59b configured as bifurcated protrusions are angularly displaced by 120 degrees. The three notches 59c defining the bifurcations extend radially inward toward the diametric center and are also angularly displaced by 120 degrees. The six link shaft holes 59d horizontally penetrate upper link element supports 59b.

Each of the three connection links 56 are provided with upper link element 60 and lower link element 61. As can be seen in FIGS. 5A to 5E, upper link element 60 is primarily configured by upper link body 62 having base end 62a and extreme end 62b. At base end 62a side, thinned tip 63a and link shaft hole 63b are provided, whereas at extreme end 62b side, notch 63c extending axially toward base end 62a and link shaft hole 63d are provided. Referring now to FIGS. 6A to 6E, lower link element 61 is primarily configured by lower link body 64 having base end 64a and extreme end 64b. At base end 64a side, link shaft hole 65a is provided, whereas at extreme end 64b side, link shaft hole 65b is provided.

Referring now to FIGS. 7A to 7E, slider 57 is primarily configured by slider body 66 provided with insert hole 67a, three lower link supports 67b, three notches 67c, and six link shaft holes 67d. Insert hole 67a allows insertion of thread spool pin 43. The three lower link element supports 67b configured as bifurcated protrusions are angularly displaced by 120 degrees. The three notches 67c defining the bifurcations extend radially inward toward the diametric center and are also angularly displaced by 120 degrees. The six link shaft holes 67d horizontally penetrate lower link element supports 67b. As can be seen in FIGS. 8A and 8B, link shaft 68 is formed as a pin.

Link base 55 and each of upper link elements 60 are assembled by: inserting thinned tip 63a at base end 62a side of upper link element 60 into notch 59c, and inserting link shaft 68 across link shaft hole 59d of link base 55 and link shaft hole 63b on base end 62a side of upper link element 60. Tight fitting is established between link shaft hole 59d and link shaft 68 and thus, link shaft 68 will not fall out after assembly. In contrast, loose fitting is established between link shaft hole 63b and link shaft 68 to allow each of upper link elements 60 to be rotatable relative to link base 55.

Each of upper link elements 60 and each of lower link elements 61 are assembled by: inserting extreme end 64b side of lower link element 61 into notch 63c of extreme end 62b side of upper link element 60, and inserting link shaft 68 across link shaft hole 63d on extreme end 62b side of upper link element 60 and link shaft hole 65b on extreme end 64b side of lower link element 61. Tight fitting is established between link shaft hole 63d and link shaft 68 and thus, link shaft 68 will not fall out after assembly. In contrast, loose fitting is established between link shaft hole 65b and link shaft 68 to allow each of upper link elements 60 and lower link elements 61 to be rotatable relative to the other.

Each of lower link elements 61 and slider 57 are assembled by: inserting base end 64a side of lower link element 61 into notch 67c of slider 57, and inserting link shaft 68 across link shaft hole 67d of slider 57 and link shaft hole 65a on base end 64a side of lower link element 61. Tight fitting is established between link shaft hole 67d and link shaft 68 and thus, link shaft 68 will not fall out after assembly. In contrast, loose fitting is established between link shaft hole 65a and link shaft 68 to allow each of lower link elements 61 to be rotatable relative to slider 57.

Link mechanism 53, as described above, is configured by an assembly of link base 55, slider 57, three upper link elements 60, three lower link elements 61, and nine link shafts 68. Link mechanism 53 is mounted on thread spool pin 43 such that thread spool pin 43 is inserted through insertion hole 59a of link base 55 and insertion hole 67a of slider 57. The outside portion of extreme end 62b of upper link element 60, which is most distant from the axial center of thread spool pin 43, is identified as contact section 69.

The inner diameter of insert hole 59a of link base 55 is configured to be slightly smaller than the outer diameter of thread spool pin 43. Thus, frictional force is exerted between the inner peripheral surface of insert hole 59a and the outer peripheral surface of thread spool pin 43 to secure thread spool pin 43 to link base 55 located at the upper portion of link mechanism 53. Link base 55 thus, stays unmoved during the attachment of the thread spool. However, by applying force that is greater than the frictional force, the user is allowed to move the positioning of link base 55. The inner diameter of insert hole 67a of slider 57, on the other hand, is configured to be greater than the outer diameter of thread spool pin 43. Thus, slider 57 located at the lower portion of link mechanism 53 is allowed to slide smoothly along thread spool pin 43. Slider 57 is disposed above compression spring 54. The three upper link elements 60, the three lower link elements 61, slider 57, and the six link shafts 68 each rests at a position where link ratio, relative positioning, joint friction, and weight are balanced. In this state, compression spring 54 is slightly compressed, meaning that the underside of slider 57 is placed in consistent contact with the upper end of compression spring 54. The slight compression, which may be referred to as the initial state, is maintained while the thread spool is not attached. As described above, slider 57 is supported by compression spring 54 and upper and lower link elements 60 and 61 conjunctively define a bend which defines a predetermined angle.

The elasticity exerted by the compression of compression spring 54 biases slider 57 upward through the contact established between compression spring 54 and slider 57. The bias exerted on slider 57 acts upon each of contact sections 69 to spread them radially by way of the three lower link elements 61.

Next, a description will be given on the working of the above described configuration.

FIGS. 9A to 9C illustrate how thread spool 71 is attached to thread spool pin 43. In the shown example, core 72 of thread spool 71 being attached has a relatively sizeable inner diameter. Thread spool 71 comprises a tapered cylindrical core 72 which is thread wound and thus, takes a generally tapered profile. As shown, thread spool 71 is manually placed over thread spool pin 43 by the user. Because the inner diameter of core 72 is less than outer diameter d1 of positioning mechanism 48 in its initial or original state, inner peripheral surface 72b of core 72 is placed in contact with each of upper link elements 60 of positioning mechanism 48. The outer diameter of positioning mechanism 48 in this context is, as represented by “d1” in FIG. 9A, a diametric dimension of an imaginary inscribing circle that contacts the three contact sections 69 in plan view. The center of the imaginary circle coincides with the center or the axial center of spool pin 43.

When the user further presses thread spool 71 downward from the state shown in FIG. 9B, each of contact sections 69 move toward the axial center of thread spool pin 43, meaning that contact sections 69 contract in the radial direction. That is, the downward movement of slider 57, which increases the angle between upper link element 60 and lower link element 61, causes each of contact sections 69 to move toward the axial center of thread spool pin 43 in equal amounts. The equal contraction of each of contact sections 69 allows thread spool 71 to move further downward.

The downward movement of slider 57 compresses compression spring 54. Responsively, the elasticity of compression spring 54 exerts upward bias to urge slider 57 upward. The bias exerted on slider 57 acts as a bias to radially expand or spread contact sections 69 provided at each of upper link element 60 by way of lower link element 61. Thus, contact sections 69 press inner peripheral surface 73b of core 72 outward. As described above, thread spool 71 being pressed by contact sections 69 is located such that axial center thereof is coincident or concentric with the axial center of thread spool pin 43 to be attached in place at the located position. This is illustrated in FIG. 9C where the diameter of the imaginary circle of positioning mechanism 48 is reduced to “d2” and compression spring 54 is compressed by “a1”.

FIGS. 10A to 10C illustrate a case in which thread spool 81 provided with core 82 having relatively smaller inner diameter is attached to thread spool pin 43. As apparent from FIG. 10C, the angle defined by upper link element 60 and lower link element 61 is greater as compared to the example shown in FIGS. 9A to 9C. The diameter of the imaginary circle defined by positioning mechanism 48 is further reduced to “d3” whereas compression spring 54 is compressed by “a2” which is greater in magnitude than “a1”.

Of note is that irrespective of downsizing of the diameter of the imaginary circle from “d1”, “d2” to “d3”, the center of the imaginary circle remains coincident with the center, i.e., the axial center of thread spool pin 43. Contact sections 69, thus, contract such that each of the contact sections 69 are equally spaced from the axial center of thread spool pin 43. Because positioning mechanism 48 is configured to contract with the inner diameter of cores 72 and 82, that is, the size of thread spools 71 and 81, the user is allowed to attach thread spools 71 and 81 to thread spool pin 43 such that the center of thread spools 71 and 81 are coincident with the axial center of thread spool pin 43 without directing extra attention in the difference in size of thread spools 71 and 81.

When the user removes thread spools 71 and 81 from thread spool pin 43, the compressed compression spring 54 is decompressed to its original state by its elasticity to place positioning mechanism 48 back to its original state shown in FIG. 9A or 10A.

According to the above described first exemplary embodiment, contact sections 69 contact inner peripheral surfaces 72b and 82b of cores 72 and 82 of thread spools 71 and 81 when thread spools 71 and 81 are attached to thread spool pin 43. Contact sections 69 are configured to be radially displaced by equal amounts responsive to the variation in the inner diameter of cores 72 and 82. This means that positioning mechanism 48 contracts radially such that the distance between the axial center of thread spool pin 43 and each of contact sections 69 are equal. As a result, the axial centers of thread spools 71 and 81 are located at the same position regardless of their difference in size. Thus, thread spools 71 and 81 can be attached to thread spool 43 at the location where the axial centers of thread spools 71 and 81 coincide with the axial center of thread spool pin 43. Because positioning mechanism 48 is configured to contract with the inner diameter of cores 72 and 82, that is, the size of thread spools 71 and 81, the user is allowed to attach thread spools 71 and 81 to thread spool pin 43 such that the center of thread spools 71 and 81 are coincident with the axial center of thread spool pin 43 without directing extra attention in the difference in size of thread spools 71 and 81. Stated differently, thread spool stand device 14 is given greater capacity to accommodate thread spools of various sizes.

Contact sections 69 contact inner peripheral surfaces 72b and 82b of cores 72 and 82 of thread spools 71 and 81 at three locations. Each of contact sections 69 moves conjunctively in coordination with one another to contract radially in equal distance to allow concerted radial contraction of positioning mechanism 48. The above described arrangement allows the axial centers of thread spools 71 and 81 to be precisely coincident with the axial center of the thread spool pin 43.

Contact sections 69 are equally spaced circumferentially from one another with an angular interval of 120 degrees. Such arrangement allows the axial centers of thread spools 71 and 81 to coincide with the axial centers of thread spool pin 43 with greater accuracy.

Positioning mechanism 48 is composed of link mechanism 53 and compression spring 54 and thus, is simple in structure and can be configured in low cost.

The elasticity of compression spring 54 biases each of contact sections 69 to protrude radially outward by way of respective lower link elements 62. As a result, each of contact sections 69 applies pressure on inner peripheral surfaces 72b and 82b of cores 72 and 82 of thread spools 71 and 81 to retain the coincident positioning of the axial centers of thread spool 71 and 81 with the axial center of thread spool pin 43.

The three contact sections 69 are each formed on one of the three upper link elements 60. Thus, once contact sections 69 are placed in contact with inner peripheral surfaces 72b and 82b of cores 72 and 82 of thread spools 71 and 81 during the attachment of thread spools 71 and 81 on thread spool pin 43, contact sections 69 retain the contact until the thread spools 71 and 81 are removed. This again, allows attachment of thread spools 71 and 81 to thread spool pin 43 such that axial centers of threads spools 71 and 81 are coincident with the axial center of thread spool pin 43.

Compression spring 54 is employed as an element for imparting elasticity to realize a simple and low cost configuration. The amount of compression of compression spring 54 is relatively less when initial contact is established between contact sections 69 and inner peripheral surfaces 72b and 82b of cores 72 and 82 and thus, contact sections 69 only impart weak outward pressure to allow smooth fitting of thread spools 71 and 81 to thread spool pin 43. By the time attachment of thread spools 71 and 81 are completed, amount of compression of compression spring 54 has increased significantly such that contact sections 69 impart a relatively strong outward pressure to reliably locate thread spools 71 and 81 relative to thread spool pin 43 as well as reliably securing them to thread spool pin 43.

FIGS. 11A and 11B illustrate a second exemplary embodiment of the present disclosure. The portions that are identical to the first exemplary embodiment are identified with identical reference symbols. The differences from the first exemplary embodiment are described hereinafter. The second exemplary embodiment provides a feature to change the positioning of the link base relative to the thread spool pin.

Between thread spool pin 91 and positioning mechanism 92, position adjustment mechanism 94 is provided for making adjustments in the positioning of link mechanism 93 relative to thread spool pin 91. More specifically, on the outer peripheral surface of extreme end 91a side of thread spool pin 91, male thread 95 is defined which runs in the predetermined length along thread spool pin 91. Positioning mechanism 92 includes link mechanism 93 and compression spring 54. Compression spring 54 is fitted over thread spool pin 91 and link mechanism 93 is further placed over thread spool pin 91 such that thread spool pin 91 is inserted through link mechanism 93 and such that link mechanism 93 is located above compression spring 54.

Link mechanism 93 includes link base 96, three connection links 56, and slider 57. On the inner peripheral surface of the central hole not shown defined through link base 96, female thread 97 is formed that is screw engaged with male thread 95. Position adjustment mechanism 94 is configured by male thread 95 of thread spool pin 91 and female thread 97 of link base 96. According to the above described configuration, the user is allowed to make adjustments in the elevation of link base 96 being secured to thread spool pin 91 through rotation of link base 96. The rotation of link base 96 causes the rotation of link mechanism 93 in its entirety.

The elevation of each of contact sections 69, that is, the positioning of each of connection link 56 relative to thread spool pin 91 can be changed by the above described configuration illustrated in FIGS. 11A and 11B. Because the change in elevation alters the amount of compression of compression spring 54, the pressure exerted on the core of the thread spools by each of contact sections 69 can be adjusted as well. In an alternative embodiment, the spring constant of compression spring 54 may be specified such that the elevation of slider 57 is not significantly changed with the change in the elevation of link base 96. Further, the angle of bend of each connection link 56 may be changed to modify the distance between the axial center of thread spool pin 91 to each of contact sections 69 in addition to the aforementioned adjustment in the elevation of contact sections 69.

Though the first exemplary embodiment also allows the user to move link base 55 up and down by application of force that overwhelms the frictional force between link base 55 and thread spool pin 43, this is not readily feasible in the user's point of view. In contrast, the second exemplary embodiment allows the user to readily move the link base 96 up and down through a simple operation of rotating link base 96 around thread spool pin 91. Additionally, compression spring 54 may have various ranges of free height and spring constant.

According to the above described second exemplary embodiment, position adjustment mechanism 94 has been provided for making adjustments in the positioning of link mechanism 93 and more specifically link base 96 relative to thread spool pin 91. Such configuration allows adjustments in the elevation of each of contact sections 69 relative to thread spool pin 91 and in the distance between the axial center of thread spool pin 91 and each of contact sections 69 through adjustment in the elevation of link mechanism 93 relative to thread spool pin 91. Such adjustments broaden the capacity of thread spool stand device 14 to accommodate thread spools 71 and 81 having various height and diametric (inner diameter) dimensions as well as allowing adjustments in the outward pressure exerted on inner peripheral surfaces 72b and 82b of cores 72 and 82 of threads spools 71 and 81 by each contact section 69.

Position adjustment mechanism 94 is configured by male thread 95 defined on the outer peripheral surface of thread spool pin 91 and female thread 97 defined on link base 96. Adjustments can be made in the positioning of link mechanism 93 relative to thread spool pin 91 by rotating link base 96 around thread spool pin 91. Thus, position adjustment mechanism 94 can be implemented in a simple and low cost configuration that allows the above described adjustments in a simple rotational operation.

The present disclosure is not limited to the foregoing exemplary embodiments but may be expanded or modified as required.

Link mechanism 53 configured by three connection links 56 being circumferentially displaced by 120 degrees maybe replaced by two connection links circumferentially displaced by 180 degrees or four connection links circumferentially displaced by 90 degrees. Five or more connection links may be provided that are circumferentially displaced by constant interval.

Connection link 56 only requires that the link is configured by at least two segments.

The first exemplary embodiment may be modified such that link base 55 is screw fastened to thread spool pin 43.

The exemplary embodiments set forth above implement thread spool stand device 14 that is structurally integral with sewing machine M. However, thread spool stand device 14 may be implemented so as to be structurally independent of sewing machine M as shown in FIG. 12. FIG. 12 illustrates thread spool stand device 101 including foot 102, leg 103 extending upward from foot 102 to hold base 104. On upper surface 104a of base 104, three disc-shaped mount stages 105 to 107 are provided with disc-shaped thread spool sponges 108 to 110 on top of them. On upper surface 32a of base 104, three thread spool pins 111 to 113 extend out of mount stages 105 to 107.

Thread spool pins 111 to 113 each have positioning mechanisms 114 to 116 attached on them that are similar in structure to positioning mechanism 48 described in the first exemplary embodiment. Provided further on upper surface 32a is support pillar 117 extending upward to support threading member 118 at its upper end. Threading member 118 overhangs thread spool pins 111 to 113 as shown in FIG. 12. FIG. 12 illustrates the case where thread spool 71 described in the first exemplary embodiment is attached to thread spool pin 112 and thread spool 81 is attached to thread spool pin 113. The positioning and the bend of each of connection links relative to thread spool pins 111 to 113 may be made adjustable as was the case in the second exemplary embodiment.

While various features have been described in conjunction with the examples outlined above, various alternatives, modifications, variations, and/or improvements of those features and/or examples may be possible. Accordingly, the examples, as set forth above, are intended to be illustrative. Various changes may be made without departing from the broad spirit and scope of the underlying principles.

Claims

1. A thread spool stand device including a thread spool base and a thread spool pin that has a base end thereof secured to the thread spool base and that allows attachment of a thread spool, the thread spool stand device comprising:

a positioning mechanism that determines position of attachment of the thread spool relative to the thread spool pin;

wherein the positioning mechanism includes a contact section that contacts an inner peripheral surface of a core of the thread spool, the contact section being radially movable responsive to variation in an inner diameter of the core such that the contact section expands radially outward or contracts radially inward to be equally spaced from an axial center of the thread spool pin.

2. The device according to claim 1, wherein more than one contact section is provided so as to contact different circumferential portions of the inner peripheral surface of the core of the thread spool, and wherein the positioning mechanism is configured such that the contact sections are moved in conjunction with one another such that the amount of the expansion and the contraction are equal.

3. The device according claim 2, wherein the contact sections are spaced at equal circumferential interval.

4. The device according to claim 2, wherein the positioning mechanism further includes:

a first support member that is securably disposed at an extreme-end side of the thread spool pin,

an elastic member that is provided on a base-end side of the thread spool pin,

a second support member that is provided on the base-end side of the thread spool pin so as to be movable in an axial direction of the thread spool pin and that is placed in consistent contact with the elastic member to be elastically biased by the elastic member; and

a plurality of connection links associated with each of the contact sections, wherein each of the connection links includes: a first link element that has a base-end side thereof rotatably supported by the first support member and that has the contact section formed on an extreme-end side thereof, a second link element that has a base-end side thereof rotatably supported by the second support member; and a connection element that rotatably connects the extreme-end sides of the first and the second link elements, wherein each pair of the first and the second link elements define a bend such that the contact section protrudes radially outward, the elastic bias exerted on the second support member by the elastic member being imparted on the contact section byway of the second link element to bias the contact section to protrude radially outward.

5. The device according claim 3, wherein the positioning mechanism further includes:

a first support member that is movably fastened to an extreme-end side of the thread spool pin,

an elastic member that is provided on a base-end side of the thread spool pin,

a second support member that is provided on the base-end side of the thread spool pin so as to be movable in an axial direction of the thread spool pin and that is placed in consistent contact with the elastic member to be elastically biased by the elastic member; and

a plurality of connection links associated with each of the contact sections, wherein each of the connection links includes: a first link element that has a base-end side thereof rotatably supported by the first support member and that has the contact section formed on an extreme-end side thereof, a second link element that has a base-end side thereof rotatably supported by the second support member; and a connection element that rotatably connects the extreme-end sides of the first and the second link elements, wherein each pair of the first and the second link elements define a bend such that the contact section protrudes radially outward, the elastic bias exerted on the second support member by the elastic member being imparted on the contact section by way of the second link element to bias the contact section to protrude radially outward.

6. The device according to claim 4, wherein the elastic member comprises a compression spring.

7. The device according to claim 5, wherein the elastic member comprises a compression spring.

8. The device according to claim 4, further comprising a position adjustment mechanism that allows a position adjustment of the first support member being secured to the thread spool pin.

9. The device according to claim 5, further comprising a position adjustment mechanism that allows a position adjustment of the first support member being secured to the thread spool pin.

10. The device according to claim 6, further comprising a position adjustment mechanism that allows a position adjustment of the first support member being secured to the thread spool pin.

11. The device according to claim 7, further comprising a position adjustment mechanism that allows a position adjustment of the first support member being secured to the thread spool pin.

12. The device according claim S, wherein the position adjustment mechanism includes:

a male thread that is formed on an outer peripheral surface of the thread spool pin, and

a female thread that is formed on the first support member and that is screw engaged with the male thread,

wherein the position adjustment of the first support member being secured to the thread spool pin is rendered by rotating the first support member around the thread spool pin.

13. The device according claim 9, wherein the position adjustment mechanism includes:

a male thread that is formed on an outer peripheral surface of the thread spool pin, and

a female thread that is formed on the first support member and that is screw engaged with the male thread,

wherein the position adjustment of the first support member being secured to the thread spool pin is rendered by rotating the first support member around the thread spool pin.

14. The device according claim 10, wherein the position adjustment mechanism includes:

a male thread that is formed on an outer peripheral surface of the thread spool pin, and

a female thread that is formed on the first support member and that is screw engaged with the male thread,

wherein the position adjustment of the first support member being secured to the thread spool pin is rendered by rotating the first support member around the thread spool pin.

15. The device according claim 11, wherein the position adjustment mechanism includes:

a male thread that is formed on an outer peripheral surface of the thread spool pin, and

a female thread that is formed on the first support member and that is screw engaged with the male thread,

wherein the position adjustment of the first support member being secured to the thread spool pin is rendered by rotating the first support member around the thread spool pin.

16. A sewing machine provided with a thread spool stand device including a thread spool base and a thread spool pin that has a base end thereof secured to the thread spool base and that allows attachment of a thread spool, sewing machine comprising:

a positioning mechanism that determines position of attachment of the thread spool relative to the thread spool pin;

wherein the positioning mechanism includes a contact section that contacts an inner peripheral surface of a core of the thread spool, the contact section being radially movable responsive to variation in an inner diameter of the core such that the contact section expands radially outward or contracts radially inward to be equally spaced from an axial center of the thread spool pin.