Cloth cutting devices for use with sewing machines

Abstract

A cloth-cutting device is attached to a sewing machine for cutting a cloth along a feeding direction of the cloth during a sewing operation. The cloth-cutting device includes a mount member mounted to the sewing machine on the side of the sewing head, an extendable member linearly vertically extendable from the mount member, and a cutter disposed at a lower end of the extendable member. The cutter is movable between a storage position on the side of a sewing head of the sewing machine and an operational position on the side of a table of the sewing machine as the extendable member moves between an upper position and a lower position.

Description

This application claims priority to Japanese patent application serial number 2003-357837, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to cutting devices for cutting a cloth along a feeding direction of the cloth during a sewing operation.

2. Description of the Related Art

In order to cut cloths during a sewing operation, various types of cutting devices have been proposed for attaching to sewing machines. For example, Japanese Laid-Open Patent Publication No. 2002-18170 teaches a cutting device that has a swing member pivotally mounted on a machine head of a sewing machine. A cutter is mounted on one end of the swing member, so that the cutter can move between a storage position within the sewing head and an operational position adjacent to a table of the sewing machine on which the cloth to be sewn is placed.

However, because the swing member pivots relative to the sewing head, a large space is required in order to permit the swinging movement of the cutter between the storage position and the operational position.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to teach improved cloth-cutting devices that require a small space for the movement of a cutter between a storage position and an operational position.

According to one aspect of the present teachings, cloth-cutting devices are taught that are attached to a sewing machine for cutting a cloth along a feeding direction of the cloth during a sewing operation. The cloth-cutting device includes a mount member mounted to the sewing machine on the side of the sewing head, an extendable member linearly vertically extendable from the mount member, and a cutter disposed at a lower end of the extendable member. The cutter is movable between a storage position on the side of a sewing head of the sewing machine and an operational position on the side of a table of the sewing machine as the extendable member moves between an upper position and a lower position.

Because the cuter moves linearly vertically together with the extendable member, the moving paths of the cutter and the extendable member are positioned on a vertical linear line. Therefore, a space required for the movement of the cutter and the extendable member is minimized. As a result, the cutting device can be easily mounted to the sewing machine.

In another aspect of the present teachings, the cloth cutting devices further include a lock device for locking the extendable member in the upper position and the lower position, a lock releasing device for releasing the lock device, and two grip portions disposed on the lower and front side of the extendable member. The lock device is released by the lock releasing member when the operator grasps the grip portions. The operator vertically moves the extendable member with the grip portions grasped by the operator. The lock device is operable to lock the extendable member when the operator releases the grip portions while the extendable member is located at the upper position and the lower position.

Because the two grip portions for releasing and locking the extendable member are disposed on the lower and front side of the extendable member, the operator can easily grasp the grip portions to operate the lock device. In addition, grasping the grip portions allows the operator to easily cause the vertical movements of the extendable member. After grasping the grip portions and vertically moving the extendable member away from the upper position and the lower position, the grip portions may be released. The extendable member may continue to be moved to the upper position and the lower position where the lock may be automatically reapplied.

In another aspect of the present teachings, the extendable member includes a fixed member and a movable member. The fixed member has a positioning portion disposed at a lower portion of the fixed member. The positioning member is positioned relative to the table of the sewing machine when the extendable member is located in the lower position.

Therefore, the positioning member can be easily positioned relative to the table when the extendable member has been extended or withdrawn downward to the lower position. Because the extending direction of the extendable member and the direction for locating the positioning member relative to the table are the same as one another, the positioning member may have a relatively simple construction.

In another aspect of the present teachings, the cutting devices further include a driven device that is driven by the needle bar. The movable member has a connecting portion that is connected to the driven device when the extendable member is positioned in the lower position. The connecting portion is disposed at an upper portion of the movable member.

Therefore, when the extendable member is positioned in the lower position to configure the cutter in an operational position, the movable member reciprocates to cut the cloth by the cutter as the needle bar reciprocates.

In another aspect of the present teachings, the cutter includes a fixed knife mounted to the lower end of the fixed member and a movable knife mounted to the lower end of the movable member.

In another aspect of the present teachings, the lock releasing device for releasing the lock device also serves to connect and disconnect between the connecting portion of the movable member and the driven device.

Because the same device can be used as the lock releasing device and as the device for connect and disconnect the movable member and the driven device, the number of parts of the cutting device can be reduced or minimized and the cutting device may have a simple construction.

In another aspect of the present teachings, the lock releasing device includes a lock operation member pivotally mounted to the fixed member about a pivotal axis. The lock operation member has a first grip portion disposed on the lower side of the pivotal axis of the lock operation member. The fixed member has a second grip portion. The lock operation member is pivoted about the pivotal axis to release the lock device when an operator grasps the first grip portion and the second grip portion. In this way, the lock operation member serves as the lock release device.

In another aspect of the present teachings, the lock operation member further includes a contact portion in a position on the upper side of the pivotal axis in order to contact with the movable member. The contact portion urges the movable member to pivot so as to disconnect between the connecting portion and the driven device when the lock operation member is pivoted to release the lock device. In this way, the operation member also serves as the device for connecting and disconnecting between the connecting portion and the driven device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view as viewed from the front side of a sewing machine to which a first representative cloth cutting device is mounted; and

FIG. 2 is a cross sectional view taken along line II-II in FIG. 1, in which a lock operation member is omitted for the purpose of illustration; and

FIG. 3 is a rear view in a storage position of the cloth cutting device; and

FIG. 4 is a view similar to FIG. 2 with an extendable member and its related parts omitted for the purpose of illustration; and

FIG. 5 is a rear view of parts of the cutting device mounted to a sewing head of the sewing machine, together with the extendable member and its related parts; and

FIG. 6 is an exploded left side view of the extendable member and its related parts; and

FIG. 7 is a view similar to FIG. 2, but showing an operational position of the cutting device; and

FIG. 8 is a view similar to FIG. 3, but showing the operational position of the cutting device; and

FIG. 9 is a view similar to FIG. 2, but showing a second representative cloth cutting device; and

FIG. 10 is a view similar to FIG. 5, but showing the second representative cutting device; and

FIG. 11 is a view similar to FIG. 4, but showing the second representative cutting device; and

FIG. 12 is an exploded left side view of the extendable member and its related parts of the second representative cutting device.

DETAILED DESCRIPTION OF THE INVENTION

Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide improved cloth cutting devices. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in conjunction with one another, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings.

FIRST REPRESENATIVE EMBODIMENT

A first representative embodiment will now be described with reference to FIGS. 1 to 8. Referring to FIG. 1, a sewing machine 10 has a table 12, a substantially inverted L-shaped arm 15 extending over the table 12, and a sewing head 11 disposed on the left end of the arm 15. The table 12 has a throat plate 13 attached to the table 12 and a feed dog 19 disposed within the table 12 in order to feed a cloth to be sewn (not shown). A motor (not shown) is mounted within the arm 15. A needle bar 14 and a presser bar 17 extend vertically downward from the sewing head 11 toward the table 12. The needle bar 14 is linked to the motor via a link mechanism (not shown), so that the needle bar 14 vertically reciprocates when the motor is energized. A presser foot 18 is attached to the lower end of the presser bar 17.

As shown in FIG. 1, a cutting device 1 is mounted to the sewing head 11. As shown in FIG. 2, the cutting device 1 includes a mount member 2 mounted within the sewing head 11, an extendable member 30 extendable linearly downward relative to the mount member 2, and a cutter 6 mounted on the lower end of the extendable member 30. The cutting device 1 further includes a driven mechanism (20, 21, 22, and 23) that is linked to the needle bar 14.

As shown in FIG. 4, the mount member 2 has mount portions 2a and 2b that are mounted on a framework 16 of the sewing machine. Rail members 2c and 2d are mounted on the mount member 2 and extend parallel to each other to define a guide portion 2e therebetween.

As shown in FIG. 4, the driven mechanism (20, 21, 22, and 23) includes a pivotal support member 23, two link members 21 and 22, and an upper connecting member 20. The needle bar 14 pivotally supports the lower end of the link member 22 via the pivotal support member 23. The upper end of the link member 22 is pivotally connected to the link member 21. The left end (as viewed in FIGS. 2 and 4) of the link member 21 is pivotally connected to the link member 22. The right end of the link member 21 is pivotally mounted to the rail member 2d. A slot 21c is formed in the right side section of the middle portion of the link member 21 and is elongated in the lengthwise direction of the link member 21.

The upper connecting member 20 has an elongated plate-like configuration and is movable in the vertical direction under the guide of the guide portion 2e. A first connecting pin 20a is secured to one side of the upper portion of the upper connecting member 20 and extends into the slot 21c of the link member 21. In this way, the upper connecting member 20 is connected to the needle bar 14 via the link member 21 and 22, so that the upper connecting member 20 reciprocates vertically as the needle bar 14 reciprocates. As shown in FIG. 4, the upper connecting member 20 has a second connecting pin 20b that is connected to the connecting portion 4d of the extendable member 4 (FIGS. 7 and 8).

As shown in FIG. 4, a positioning member 7 that also serves a lock member is disposed within the sewing head 11. The positioning member 7 extends perpendicularly from the rail member 2d and has two engaging recesses 7a and 7b as shown in FIG. 5. The engaging recesses 7a and 7b are adapted to engage an engaging pin 5e secured to an operation member 5 connected to the extendable member 30 as will be explained later. When the engaging pin 5e engages the engaging recess 7a as shown in FIG. 3, the extendable member 30 may be locked in a storing position. On the other hand, when the engaging pin 5e engages the engaging recess 7b as shown in FIG. 8, the extendable member 30 may be locked in an operational position.

As shown in FIG. 6, the extendable member 30 has a fixed member 3 and a movable member 4. The fixed member 3 has a plate-like configuration and extends in the vertical direction. A recess 3a is formed in the upper end of the fixed member 3. A fixed knife 60 is fixedly attached to the lower end of the fixed member 3. A grip portion 3d is formed on the front side (right side as viewed in FIG. 6) of the fixed member 3. Also, an uprising portion 3b is formed on the front edge of the fixed member 3 and extends perpendicular to the fixed member 3. As shown in FIG. 2, the width of the fixed member 3 is substantially the same as the width of the guide portion 2e. Therefore, the fixed member 3 is prevented from being tilted in the forward and rearward directions. As shown in FIG. 5, the fixed member 3 is positioned between the mount member 2 and the upper connecting member 20. Therefore, the fixed member 3 is also prevented from being tilted in the light and left directions, i.e., the direction of thickness of the fixed member 3. In this way, the fixed member 3 can stably move vertically relative to the mount member 2.

As shown in FIG. 6, the movable member 4 also has a plate-like configuration and extends in the vertical direction. As shown in FIG. 8, the movable member 4 is arranged parallel to the fixed member 3 in the direction of thickness. As shown in FIG. 6, the movable member 4 has an uprising portion 4a, a connecting portion 4d, and a mount portion 4c. The uprising portion 4a extends perpendicular to the movable member 4 and has a through-hole through which one end of a wire spring 50 is inserted, as will be explained later. The connecting portion 4d is configured as a through hole formed in the upper portion of the movable member 4 in order to removably receive the second connecting pin 20b as shown in FIG. 8. The mount portion 4c is disposed at the lower end of the movable member 4. A movable knife 61 is pivotally mounted to the mount portion 4c.

As shown in FIG. 6, the cutter 6 includes the fixed knife 60 and the movable knife 61. As noted previously, the fixed knife 60 is fixedly attached to the lower end of the fixed member 3. The fixed knife 60 has a mount portion 60c, a positioning portion 60a, and a knife-edge 60d. The positioning portion 60a is disposed at the lower end of the fixed knife 60 and extends downwardly therefrom. As shown in FIG. 7, the positioning portion 60a is inserted into an insertion hole 13a formed in the throat plate 13 so as to be fixed in position relative to the table 12. The mount portion 60c is formed in the rear portion of the fixed knife 60. The mount portion 61a of the movable knife 61 is pivotally mounted to the mount portion 60c.

As shown in FIG. 6, the movable knife 61 extends in substantially forward and rearward directions. The rear portion of the movable knife 61 is pivotally mounted to the fixed knife 60. The front portion of the movable knife 61 is pivotally mounted to the mount portion 4c of the movable member 4. Therefore, as the movable member 4 vertically reciprocates, the movable knife 61 pivots about the mount portion 60c, so that a knife-edge 61b of the movable knife 61 vertically reciprocates relative to the knife-edge 60d of the fixed knife 60.

As shown in FIG. 6, the cutting device has a lock operation member 5 disposed on the side of the extendable member 30. Also, the lock operation member 5 has a plate-like configuration and extends in the vertical direction. The lock operation member 5 has a mount portion 5c disposed in a substantially middle portion in the longitudinal direction. The mount portion 5c is configured as a through-hole extending throughout the thickness of the lock operation member 5. The mount portion 5c is pivotally mounted to the uprising portion 3b of the fixed member 3 via a support member 31. Thus, the lock operation member 5 is positioned to be perpendicular to the fixed member 3 as shown in FIG. 8, and the lock operation member 5 can pivot relative to the fixed member 3 in the right and left directions (i.e., the direction of thickness of the fixed member 3).

As shown in FIG. 6, a contact portion 5h is formed on the upper end of the lock operation member 5. As shown in FIG. 8, the contact portion 5h extends to a position between the movable member 4 and the fixed member 3, so that the movable member 4 may move away from the fixed member 3 by the contact portion 5h when the lock operation member 5 is pivoted. As shown in FIG. 6, the contact portion 5h has a tilting movement preventing portion 5j that serves to prevent the movable member 4 from being pivoted in the forward and rearward directions.

As shown in FIG. 6, a grip portion 5g is formed on the lower end of the lock operation member 5. The grip portion 5g extends forwardly from the lock operation member 5. In the assembled state shown in FIG. 8, the grip portion 5g and the grip portion 3d of the fixed member 3 extend parallel to each other in the forward direction. If the operator grasps the grip portions 3d and 5g with his or her hand, the grip portion 5g may be moved toward the grip portion 3d, so that the lock operation member 5 pivots about the mount portion 5c.

As shown in FIG. 5, two wire springs 50 and 51 are mounted to the lock operation member 5. The wire spring 51 extends between the lock operation member 5 and the fixed member 3 in order to bias the lower portion of the lock operation member 5 in a counterclockwise direction as viewed in FIG. 5. The wire spring 50 extends between the lock operation member 5 and the movable member 4 in order to bias the upper portion of the lock member 5 also in the counterclockwise direction (the direction on the side of the contact portion 5h).

As shown in FIG. 5, the engaging pin 5e positioned on the upper portion of the lock operation member 5e is forced to engage the engaging recess 7a or 7b (see FIGS. 3 and 8) by the biasing force applied to the operation member 5 via the wire spring 51. Thus, the engaging pin 5e can be reliably held in engagement with the engaging recess 7a or 7b. This condition will be hereinafter called a “lock condition.” In order to disengage the engaging pin 5e from the engaging recess 7a or 7b, operator may simply grasps the grip portions 3d and 5g, so that the lock operation member 5 pivots against the biasing force of the wire spring 51 to remove the engaging pin 5e from the engaging recess 7a or 7b. This condition will be hereinafter called a “lock releasing condition.”

As shown in FIG. 8, the wire springs 50 and 51 bias the movable member 4 toward the fixed member 3 via the lock operation member 5. Therefore, the connecting portion 4d of the movable member 4 is forced toward the second connecting pin 20b, so that the connecting portion 4d can be reliably held in engagement with the connecting pin 20b. This condition will be hereinafter called a “connecting condition.” In order to disengage the connecting portion 4d from the connection pin 20b, the operator may simply grasps the grip portions 3d and 5g, so that the lock operation member 5 is pivoted against the biasing force of the wire spring 51 and the contact portion 5h contacts or engages the movable 4 to pivot the movable member 4. As a result, the connecting portion 4d is removed from the second connecting pin 20b. This condition will be hereinafter called a “disconnecting condition.”

Further, in the storage position of the extendable member 30, as shown in FIG. 3, the connecting pin 20b and the connecting portion 4d are offset from each other in the vertical direction. Thus, the connecting pin 20b and the connecting portion 4d are held in the disconnecting condition while in the storage position. In addition, in the storage position, the engaging pin 5e engages the engaging recess 7a, so that the movable member 4 is held in the pivoted position. As a result, the movable member 4 can be further prevented from contacting with the connecting pin 20b.

As shown in FIGS. 6 and 8, a leaf spring 40 is mounted to the lower portion of the fixed member 3 via a mount base 41 and serves to bias the movable member 4 toward the fixed member 3. Therefore, the movable knife 61 mounted to the movable member 4 is pressed by a large force to contact with the fixed knife 60 mounted to the fixed member 3. Therefore, the movable knife 61 can reliably cut the cloth due to cooperation with the fixed knife 60.

The operation for moving the extendable member 30 from the storage position to the operational position will now be described. First, the operator grasps the grip portions 3d and 5g (see FIGS. 2 and 3) in order to disengage the engaging pin 5e from the engaging recess 7a. Subsequently, with the grip portions 3d and 5g grasped, the operator pulls or withdraws the extendable member 30 downward and inserts the positioning portion 60a into the insertion hole 13a as shown in FIG. 7. In this way, the lower end of the fixed member 3 is positioned relative to the table 12. Thereafter, the operator releases the grip portions 3d and 5g, so that the engaging pin 5e engages the engaging recess 7b and the connecting portion 4d of the movable member 4 engages the connecting pin 20b of the upper connecting member 20. In this condition, the movable member 4 can vertically reciprocate as the needle bar 14 reciprocates.

In order to move the extendable member 30 from the operational position to the storage position, the operation may grasp the grip portions 3d and 5g (see FIG. 8), so that the engaging pin 5e is disengaged from the engaging recess 7b and the connecting portion 4d is disengaged from the connecting pin 20b. Subsequently, with the grip portions 3d and 5g grasped, the operator lifts the extendable member 30. Thereafter, the operator releases the grip portions 3d and 5g, so that the engaging pin 5e engages the engaging recess 7a as shown in FIG. 3.

According to the representative embodiment, the cutter 6 moves linearly upward and downward together with the extendable member 30 relative to the mount member 2 as shown in FIGS. 2 and 7. Consequently, the paths of the upward and downward movements of the cutter 6 and the extendable member 30 are positioned along a linear line. Therefore, the space required for the movement of the cutter 6 and the extendable member 30 is minimized. In other words, the cutting device 1 can be easily and compactly mounted to the sewing machine 10.

In addition, according to the representative embodiment, the lock operation member 5 also serves as a lock releasing device, and the positioning member 7 and the engaging pin 5e constitute a lock device. Consequently, the lock releasing device (5) is configured to release the lock device (7, 5e) via the grip portions 3d and 5g. Because the grip portions 3d and 5g are disposed on the lower front side of the extendable member 30, the operator of the sewing machine can readily grasp the grip portions 3d and 5g to operate the lock device. In addition, while the grip portions 3d and 5g are grasped, the operator can easily move the extendable member 30 in the upward and downward directions.

Further, as shown in FIGS. 6 and 7, the extendable member includes the fixed member 3 and the movable member 4. The cutter 6 includes the fixed knife 60 and the movable knife 61 respectively mounted to the fixed member 3 and the movable member 4. The positioning member 60a is disposed at the lower end of the fixed member 3 and is positioned relative to the table 12 of the sewing machine 10.

Therefore, the positioning member 60a can be easily positioned relative to the table 12 as the fixed member 3 moves in the downward direction, i.e., withdrawing direction from sewing head 11. In contrast, the cloth-cutting device of Japanese Laid-Open Patent Publication No. 2002-18170 has a positioning means disposed at a lower end of a swing member that pivots relative to the sewing machine. In addition, the positioning means is extended from the lower end of the swing member after the swing member has been swung or pivoted to an operational position. Thus, the moving direction of the swing member and the moving direction of the positioning means are different from one another. According to the representative embodiment, the moving direction of the positioning member 60a for positioning relative to the sewing machine is the same as the extending direction of the extendable member 30. Therefore, the positioning member 60a may have a simple construction. In other words, the positioning member 60a is not necessary to extend and retract relative to the extendable member.

Furthermore, as shown in FIG. 8, the upper connecting member 20 serves as a driven device that is driven by the needle bar 14. The lock releasing device (5) is configured to enable the connecting portion 4d of the movable member 4 to be connected to or disconnected from the driven device (20). In this way, the lock releasing device (5) also serves to connect and disconnect between the connecting portion 4d and the driven device (20), so that the same parts can be commonly used for different functions. Therefore, the construction of the cutting device 1 can be simplified. In addition, in the storage position shown in FIG. 3, the movable member 4 is disconnected from the driven device (20). Therefore, it is possible to minimize the waste of energy of the sewing machine.

Thus, the lock operation member 5 can pivot relative to the fixed member 3 in order to release the lock device (7, 5e) and to disengage or disconnect the connecting portion 4d from the driven device (20).

SECOND REPRESENTATIVE EMBODIMENT

A second representative embodiment will now be described with reference to FIGS. 9 to 12. The second representative embodiment is a modification of the first representative embodiment. Therefore, in FIGS. 9 to 12, like members are given the same reference numerals as in the first representative embodiment and the explanation of these members may not be repeated.

As shown in FIG. 9, a cloth cutting device 101 according to the second representative embodiment includes an extendable member 130, a cutter 106, a driven device (120, 121, 122, 23), and a positioning member 107 in addition to the mount member 2. The cutting device 101 also has a lock operation member 105 (see FIG. 12). The extendable member 130 includes a fixed member 103 and a movable member 104.

As shown in FIG. 9, the driven device includes a first link member 122 pivotally mounted to the needle bar 14 and a second link member 121 pivotally connected to the first link member 122. As shown in FIG. 11, the driven device further includes an upper connecting member 120. A first connecting pin 120a is mounted to the upper portion of the upper connecting member 120 and is inserted into an elongated slot 121c formed in the second link member 121. A second connecting pin 120b is mounted to the lower portion of the upper connecting member 120. The second connecting pin 120b is adapted to engage a connecting portion 104d formed in the movable member 104 of the extendable member 130 when the movable member 104 has been extended downward or withdrawn downward.

A cutout portion 103a is formed in the upper portion of the fixed member 103. A fixed knife 160 is mounted to the lower end of the fixed member 103. The fixed knife 160 includes a mount portion 160c, a positioning portion 160a, a knife edge 160d, and a grip portion 103d. The grip portion 103d extends on the front side of the fixed member 103 and a grip member 103e, preferably made of resin, is fitted on the grip portion 103d.

As shown in FIG. 12, a contact portion 104a is formed on the upper end of the movable member 104. A movable knife 161 is pivotally mounted to the lower end of the movable member 104. A mount portion 161a is disposed at the rear portion of the movable knife 161 and is pivotally mounted to the mount portion 160c of the fixed knife 160. Consequently, the front portion of the movable knife 161 pivots about the mount portion 104c of the movable member 104.

As shown in FIG. 9, the contact portion 104a extends in the right side direction (perpendicular to the sheet of FIG. 9), so that the contact portion 104a contacts with an extension 107a formed on the upper end of the positioning member 107 when the extendable member 130 is located in a storage position as shown in FIG. 9. Therefore, the position of the movable member 104 relative to the fixed member 103 can be determined by the contact portion 104a, so that the pivotal position of the movable knife 161 is held in a position as shown in FIG. 9, where the movable knife 161 and the fixed knife 160 are substantially overlaid with one another. Therefore, the knife edges of the movable knife 161 and the fixed knife 160 have only a minimum area exposed to the outside when the extendable member 130 is located in the storage position.

As shown in FIG. 12, a mount base 141 is fixedly mounted to the fixed member 103. The mount base 141 has a mount plate 141a for mounting to the fixed member 103, an uprising plate 141b extending perpendicular to the mount plate 141a, and a turn-back plate 141c bent to be turned back from the upper portion of the uprising plate 141b. A leaf spring 140 has an upper end that is secured to the turn-back plate 141c. The lower end of the leaf spring 140 contacts the mount portion 104c of the movable member 104 in order to bias the fixed knife 160 against the movable knife 161. Consequently, the fixed knife 160 is pressed against the movable knife 161 so that the fixed knife 160 reliably cooperates with the movable knife 161 in order to cut the cloth.

As shown in FIG. 12, a contact portion 105h, a tilting movement preventing portion 105j, and an engaging pin 105e, are formed on the upper portion of the lock operation member 105. A grip portion 105g is formed on the lower end of the lock operation member 105. A mount portion 105c is formed in substantially the middle position in the longitudinal direction of the lock operation member 105. The mount portion 105c is pivotally mounted to the uprising plate 141b of the mount base 141 via the support member 31. The grip portion 105g extends forwardly from the lock operation member 105. A grip member 105k, preferably made of resin, is fitted on the grip portion 105g. In addition, the grip member 105k is received within a recess 103e1 formed in the grip member 103e of the fixed member 103. The grip member 105k is movable within the recess 103e1 in the direction of the depth of the recess 103e1. Therefore, when the operator grasps the grip members 103e and 105k, the grip member 105k moves toward the grip member 103e, so that the lock operation member 105 pivots about the mount portion 105c.

As shown in FIGS. 10 and 12, a wire spring 151 is attached between the lock operation member 105 and the fixed member 103, so that the wire spring 151 biases the lock operation member 105 in a counterclockwise direction as viewed in FIG. 10. A wire spring 150 is attached between the lock operation member 105 and the movable member 104, so that the wire spring 150 biases the movable member 104 toward the contact portion 105h of the lock operation member 105.

With the second representative embodiment, substantially the same operation and advantages can be attained as the first representative embodiment.

Claims

1. A cloth-cutting device attached to a sewing machine, which has a sewing head, a needle bar, and a table positioned below the sewing head, for cutting a cloth along a feeding direction of the cloth during a sewing operation, comprising:

a mount member mounted to the sewing machine on the side of the sewing head; and

an extendable member linearly vertically extendable from the mount member;

a cutter disposed at a lower end of the extendable member;

wherein the cutter is movable between a storage position on the side of the sewing head of the sewing machine and an operational position on the side of the table of the sewing machine as the extendable member moves between an upper position and a lower position.

2. The cloth-cutting device as in claim 1, further comprising:

a lock device arranged and constructed to lock the extendable member in the upper position and the lower position; and

a lock releasing device arranged and constructed to release the lock device; and

two grip portions disposed on the lower front side of the extendable member;

wherein the lock device is released by the lock releasing member when the grip portions are grasped by an operator, and

wherein the extendable member is vertically moved by the operator while the grip portions are grasped by the operator; and

wherein the lock device is operable to lock the extendable member when the operator releases the grip portions and the extendable member is positioned at one of the upper position and the lower position.

3. The cloth-cutting device as in claim 1,

wherein the extendable member comprises a fixed member and a movable member; and

wherein the fixed member has a positioning portion disposed at a lower portion of the fixed member; and

wherein the positioning member is positioned relative to the table of the sewing machine when the extendable member is positioned at the lower position.

4. The cloth-cutting device as in claim 3, further comprising a driven device arranged and constructed to be driven by the needle bar, and

wherein the movable member has a connecting portion arranged and constructed to be connected to the driven device when the extendable member is positioned at the lower position, and

wherein the connecting portion is disposed at an upper portion of the movable member.

5. The cloth-cutting device as in claim 4, wherein the cutter comprises a fixed knife mounted to the lower end of the fixed member and a movable knife mounted to the lower end of the movable member.

6. The cloth-cutting device as in claim 4, further comprising:

a lock device arranged and constructed to lock the extendable member at the upper position and the lower position; and

a lock releasing device arranged and constructed to release the lock device and to connect and disconnect the connecting portion of the movable member and the driven device.

7. The cloth-cutting device as in claim 6,

wherein the lock releasing device comprises a lock operation member pivotally mounted to the fixed member about a pivotal axis; and

wherein the lock operation member has a first grip portion disposed on the lower side of the pivotal axis of the lock operation member; and

wherein the fixed member has a second grip portion; and

wherein the lock operation member is pivoted about the pivotal axis to release the lock device when the first grip portion and the second grip are grasped by an operator.

8. The cloth-cutting device as in claim 7,

wherein the lock operation member further includes a contact portion in a position on the upper side of the pivotal axis; and

wherein the contact portion is arranged and constructed to contact with the movable member; and

wherein the contact portion urges the movable member to pivot so as to disconnect the connecting portion from the driven device when the lock operation member is pivoted to release the lock device.