EP2594672A1

EP2594672A1 - Flatbed knitting machine including variable stitch device

Info

Publication number: EP2594672A1
Application number: EP12007497.6A
Authority: EP
Inventors: Masaki Miyamoto
Original assignee: Shima Seiki Mfg Ltd
Current assignee: Shima Seiki Mfg Ltd
Priority date: 2011-11-17
Filing date: 2012-10-31
Publication date: 2013-05-22
Anticipated expiration: 2032-10-31
Also published as: JP2013108184A; EP2594672B1; CN103122552A; CN103122552B; KR20130054913A; KR101356983B1

Abstract

A flatbed knitting machine includes a variable stitch device (25) that has a simple structure for cost reduction and has a compact size for reduction of a mount space on a carriage. The variable stitch device (25) includes a first groove (37) and a second groove (38) juxtaposed in a cam plate (21) and extending parallel to an inclined face of a bridge cam (23), a control cam (44) performs control to move a first cam (31) having a first stitch-size determining cam face (35) engageable with a second butt (14) of full height along the first groove (37), to move a second cam (32) having a second stitch-size determining cam face (34) engageable with the second butt (14) of half height along the second groove (38), and to switch the first stitch-size determining cam face (35) and the second stitch-size determining cam face (34) between an even state and a stepped state, and a stepping motor (48) that drives the control cam (44).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flatbed knitting machine including a variable stitch device that can form stitches of different sizes in the same knitting course of a carriage.

2. Description of the Related Art

In this description, in relation to a butt, a full height refers to a state in which the butt is not pressed by a presser, a half height refers to a state in which the butt is pressed by the presser to be sunk by about half, and a zero height refers to a state in which the butt is pressed by the presser. In relation to a cam and the presser, as the cam becomes closer to a needle bed, the cam surface increases in height. The cam of full height is engageable with the butt of half height and the butt of full height. The cam of half height is engageable only with the butt of full height. A front side and a rear side with respect to a running direction of a carriage are referred to as a leading side and a trailing side, respectively. With respect to a moving direction of a knitting needle, a side of a needle bed gap is referred to as a front side, and an opposite side is referred to as a rear side. Similarly, when parts of the cam are expressed, a front side of the cam refers to a side closer to the needle bed gap, and a rear side of the cam refers to a side remote from the needle bed gap. In addition, a height in an up-down direction refers to a height in a direction orthogonal to the drawing (plane of paper).
A variable stitch device has hitherto been used to form stitches of different sizes in the same knitting course produced at a single traverse of a carriage in a flatbed knitting machine. For example, as disclosed in Japanese Patent No. 4016031 , the variable stitch device includes a first cam and a second cam that move parallel to an inclined face of a bridge cam provided on a cam plate. The first cam has a first stitch-size determining cam face engageable with a butt of full height to form a large-sized stitch, and the second cam has a second stitch-size determining cam face engageable with the butt of half height to form a small-sized stitch. When a butt of a needle jack, which is drivingly connected to a needle body, moves on the cam face and is pulled rearward, a hook of a needle pulls in knitting yarn to form a stitch. At this time, a step difference is formed between the first stitch-size determining cam face and the second stitch-size determining cam face so that small-sized and large-sized stitches can be formed in the same knitting course.
However, in the related art, the first cam and the second cam are driven by two different drive sources. In this case, since the first cam and the second cam need to be provided on each of the right and left sides in the variable stitch device, a total of four drive sources are necessary. For this reason, the structure of the variable stitch device is complicated, and the cost is increased. Moreover, the size of the variable stitch device is inevitably increased, and this needs a wide mount space on the carriage.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a flatbed knitting machine including a variable stitch device that has a simple structure for cost reduction and has a compact size for reduction of a mount space on a carriage.
To achieve the above object, the present invention provides a flatbed knitting machine including a variable stitch device. The variable stitch device includes a first cam and a second cam that move in a moving direction parallel to an inclined face of a bridge cam provided on a cam plate and that engage with a butt whose protruding height from a needle bed is set to a full height and a half height by a press of a presser provided on a carriage to advance and retreat a knitting needle, the first cam having a first stitch-size determining cam face engageable with the butt of the full height to form a large-sized stitch, the second cam having a second stitch-size determining cam face engageable with the butt of the half height to form a small-sized stitch, the small-sized stitch and the large-sized stitch being formed in the same knitting course by forming a step difference between the first stitch-size determining cam face and the second stitch-size determining cam face. The variable stitch device further includes a control cam that moves the first cam and the second cam in the moving direction so that the first stitch-size determining cam face and the second stitch-size determining cam face are switched between an even state and a stepped state, and drive means that drives the control cam in a rotating direction. The control cam includes a first cam sliding face that moves the first cam in the moving direction by sliding contact therewith via a first sliding contact member, and a second cam sliding face that moves the second cam in the moving direction by sliding contact therewith via a second sliding contact member. A distance between the first cam sliding face and the second cam sliding face in the rotating direction of the control cam differs in a plurality of steps or in a stepless manner in a circumferential direction.
Preferably, the control cam includes a substantially annular projecting or recessed sliding contact portion that has the first cam sliding face on an outer peripheral side and the second cam sliding face on an inner peripheral side and that is supported rotatably about a shaft of the control cam, and distances between the shaft and the first cam sliding face and the second cam sliding face are changed in association with rotation of the cam sliding contact portion about the shaft. One of the first and second sliding contact members is supported by the first cam, and the other sliding contact member is supported by one end of an arm that is turnably supported at a longitudinal middle portion by the first cam and is supported at the other end by the second cam.
Preferably, the first and second sliding contact members are formed by rollers.
According to the flatbed knitting machine including the variable stitch device of the present invention, when the control cam is rotated by the drive means, the first cam in sliding contact with the first cam sliding face via the first sliding contact member and the second cam in sliding contact with the second cam sliding face via the second sliding contact member move parallel to the inclined face of the bridge cam to change the pull-down amount of the butt of full height and half height. In this case, the first stitch-size determining cam face and the second stitch-size determining cam face are switched between an even state or a stepped state in accordance with the distance between the first cam sliding face and the second cam sliding face that are changed in the circumferential direction in a plurality of steps or in a stepless manner in the rotating direction of the control cam. This makes it possible to make a difference between the sizes of a stitch formed by the knitting needle with the butt of full height and a stitch formed by the knitting needle with the butt of half height.
Thus, only two drive sources are provided in the variable stitch device, and this simplifies the structure of the variable stitch device. Moreover, the size of the variable stitch device can be reduced, and the mount space on the carriage can be made compact.
When the control cam is rotated about the shaft by the drive means, the distance from the sliding contact position where the first and second sliding contact members are in contact with the sliding contact portion to the shaft changes, and the first cam and the second cam move parallel to the inclined face of the bridge cam in accordance with the distance, so that the pull-down amount of the butt of full height and half height is changed. In this case, the first stitch-size determining cam face and the second stitch-size determining cam face are switched between an even state and a stepped state in accordance with the distance between the first cam sliding face and the second cam sliding face. This makes it possible to make a difference between the size of a stitch formed by the knitting needle with the butt of full height and the size of a stitch formed by the knitting needle with the butt of half height.
The control cam that rotates about the shaft includes the substantially annular projecting or recessed sliding contact portion that has the first cam sliding face on an outer peripheral side and the second cam sliding face on an inner peripheral side. Hence, the pull-down amount of the butt of full height and half height and the step difference between the first stitch-size determining cam face and the second stitch-size determining cam face can be changed with a simple structure.
Moreover, since the other sliding contact member is supported by the first cam with the arm being disposed therebetween, it can be separated from the first cam by the arm.
In addition, since the sliding contact members are formed by the rollers, smooth sliding contact with the first and second cam sliding faces can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a side view of a knitting needle for use in a flatbed knitting machine including a variable stitch device according to an embodiment of the present invention;
Fig. 2 is a bottom view of a cam unit during running of a carriage to the left side of Fig. 2, as viewed from a knitting needle side;
Fig. 3 is a bottom view of one of stitch cams in the variable stitch device of Fig. 1, as viewed from the knitting needle side;
Figs. 4A to 4D are bottom views illustrating states in which components of the stitch cam of Fig. 3 are removed in order from the knitting needle side;
Fig. 5 is a sectional view of the stitch cam of Fig. 3, taken along line V-V of Fig. 3;
Fig. 6 is a right side view of the stitch cam of Fig. 3, as viewed from a right side in a running direction of the carriage;
Figs. 7A to 7D are bottom views of the stitch cam, illustrating states in which the pull-down amount of a second butt is changed without forming any step difference; and
Figs. 8A to 8D are bottom views of the stitch cam, illustrating states in which the pull-down amount of the second butt is changed while forming a step difference S1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, a flatbed knitting machine including a variable stitch device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.
Fig. 1 is a side view of a knitting needle 1. In the knitting needle 1, a needle body 11 is combined at its tail with a needle jack 12. The knitting needle 1 is moved forward and backward by engagement of a first butt 13 and a second butt 14 provided in the needle jack 12 with cams provided in a cam unit 2 (illustrated in Fig. 2). The first butt 13 and the second butt 14 project from front and rear portions of the needle jack 12 that are spaced apart a predetermined distance.
An arm 15 provided at the rear of the needle jack 12 biases the second butt 14 upward (toward the cam unit 2) so that the second butt 14 protrudes out of a needle groove. After needle selection is performed by one of selectors arranged in parallel below a needle bed in a needle selection actuator provided on an unillustrated carriage, a select jack operatively connected to the selector is moved to two different positions. According to this positional relationship, a presser presses a butt of the select jack to set a butt of half height, and does not press the butt to set a butt of full height. The first butt 13 provided near a connecting portion to the needle body 11 constantly keeps a position to protrude outside the needle groove, regardless of the pressing operation of the presser.
Fig. 2 is a bottom view of the cam unit 2 during running of the carriage to the left side of Fig. 2, as viewed from a knitting needle 1 side. Referring to Fig. 2, the cam unit 2 is mounted on the carriage such as to be provided symmetrically with respect to a center line X of a cam plate 21. In the cam unit 2, a needle raising cam 22 is provided at the center of the cam plate 21, a bridge cam 23 is provided in front of (on a leading side in a moving direction of the knitting needle 1 of) the needle raising cam 22, and stitch cams 25a and 25b of a variable stitch device 25 are provided on left and right sides, respectively, of the needle raising cam 22 with a path 24 for the second butt 14 of the needle jack 12 being disposed therebetween. The stitch cams 25a and 25b are movable frontward and rearward in a direction substantially parallel to inclined faces of the bridge cam 23. A transfer receiving cam 26 is provided inside the needle raising cam 22. A transfer cam 28 is provided in front of the bridge cam 23, and includes a retractable transfer cam 28a and a transfer guide cam 28b.
Fig. 3 is a bottom view of one of the stitch cams, that is, the stitch cam 25a in the variable stitch device 25 illustrated in Fig. 2, as viewed from a lower side (the knitting needle 1 side), and Figs. 4A to 4D are bottom views illustrating states in which components of the stitch cam 25a of Fig. 3 are removed in this order from the lower side. Fig. 4A illustrates a first cam and a second cam on the cam plate 21, and Fig. 4B illustrates a first presser plate and a second presser plate in a state in which the first cam and the second cam are removed. Fig. 4C illustrates an arm in a state in which the first presser plate and the second presser plate are removed, and Fig. 4D illustrates a control cam and a stepping motor in a state in which the arm is removed. Fig. 5 is a cross-sectional view, taken along line V-V of Fig. 3, and Fig. 6 is a right side view of the stitch cam 25a of Fig. 3, as viewed from a right side in the running direction of the carriage.
Since the stitch cams 25a and 25b have the same structure, a description will be given of only the stitch cam 25a. The stitch cam 25a includes a first cam 31, a second cam 32, and an arm 33. The first cam 31 has a first stitch-size determining cam face 35 that engages with the second butt 14 of full height to form a stitch larger than the knitting needle 1 with the second butt 14 of half height. The second cam 32 has a second stitch-size determining cam face 34 that engages with the second butt 14 of half height.
The cam plate 21 has a first groove 37 and a second groove 38 extending parallel to the corresponding inclined face of the bridge cam 23. In the first groove 37 and the second groove 38, a support block 37a and a support block 38a (illustrated in Fig. 5) are slidably provided, respectively. The support block 37a in the first groove 37 is interposed between the first cam 31 and a first presser plate 41 that slidably supports the first cam 31 from a back side of the cam plate 21, and is fixed to the first cam 31 and the first presser plate 41 by a bolt 40. This allows the first cam 31 to move along the first groove 37. In contrast, the support block 38a in the second groove 38 is interposed between the second cam 32 and a second presser plate 42 that slidably supports the second cam 32 from the back side of the cam plate 21, and is fixed to the second cam 32 and the second presser plate 42 by a bolt 40. This allows the second cam 32 to move along the second groove 38.
The arm 33 is turnably supported at almost the longitudinal center by a shaft 43 that projects upward from a right front end of the first presser plate 41. A roller 49 is supported at one end of the arm 33 (a right end in Figs. 3 and 4A to 4D), and the roller 49 is received in a recess 42a provided in a front end of the second presser plate 42 such as to be movable in the right-left direction.
The stitch cam 25a further includes a control cam 44 provided on a back side (upper side) of the arm 33. The control cam 44 includes a circular plate 45, a substantially annular sliding contact portion 46 that projects downward (toward the arm 33) from a rim of the plate 45, and a boss portion 47 serving as a shaft projecting upward from the plate 45. The sliding contact portion 46 includes two thickness portions, namely, a first thickness portion 46a and a second thickness portion 46b that are different in radial thickness in a circumferential direction with a boundary at a circumferential reference position (a position clamped between below-described inner and outer rollers 51 and 52 in Fig. 3). The thickness of the second thickness portion 46b is more than the thickness of the first thickness portion 46a. In the center of the boss portion 47, for example, an output shaft 48a of a stepping motor 48 serving as a driving means is corotatably fitted. The output shaft 48a is rotatable forward and in reverse. The driving means is not limited to the stepping motor 48, and may be other motors such as a servomotor.
The first and second thickness portions 46a and 46b of the sliding contact portion 46 are clamped between a pair of inner and outer rollers 51 and 52 serving as first and second sliding contact members from inner and outer sides. The outer roller 52 in sliding contact with outer peripheral sides of the first and second thickness portions 46a and 46b is rotatably supported at a front end of the first presser plate 41. In contrast, the inner roller 51 in sliding contact with inner peripheral sides of the first and second thickness portions 46a and 46b is rotatably supported at the other end of the arm 33 (a left end in Figs. 3 and 4A to 4D). The plate 45 is provided with a detection piece 45a that detects the reference position of the sliding contact portion 46 with a sensor 50.
The thickness of the second thickness portion 46b is made large by reducing the diameter of the inner peripheral side of the sliding contact portion 46 more than in the first thickness portion 46a. For this reason, the distance of the inner roller 51 from the outer roller 52 is increased in the second thickness portion 46b because the second thickness portion 46b is thicker than the first thickness portion 46a.
A hook 53 is fixed to a right rear end of the first presser plate 41. Between the hook 53 and one end of the arm 33, a bias spring 54 is provided to press the inner and outer rollers 51 and 52 against the inner and outer peripheral sides of the first and second thickness portions 46a and 46b. In this case, the inner roller 51 is pressed against the inner peripheral sides of the first and second thickness portions 46a and 46b via the arm 33 by a biasing force of the bias spring 54, and the outer roller 52 is pressed against the outer peripheral sides of the first and second thickness portions 46a and 46b by a rearward pulling force of the first presser plate 41 that receives reaction force to the biasing force. An outer peripheral side of the sliding contact portion 46 serves as a first cam sliding face 462 that moves the first cam 31 along the first groove 37 by sliding contact with the slider base body 31 with the outer roller 52 being disposed therebetween, and an inner peripheral side of the sliding contact portion 46 serves as a second cam sliding face 461 that moves the second cam 32 along the second groove 38 by sliding contact with the second cam 32 with the inner roller 51 and the arm 33 being disposed therebetween. With this structure, the inner and outer rollers 51 and 52 follow the first and second thickness portions 46a and 46b in tight contact therewith according to the thicknesses, and no clamp error is formed between the inner and outer rollers 51 and 52. This allows the first stitch-size determining cam face 35 and the second stitch-size determining cam face 34 to be reliably held in an even state or in a stepped state. Moreover, when the inner and outer rollers 51 and 52 are in sliding contact with the first and second cam sliding faces 462 and 461 of the first and second thickness portions 46a and 46b, smooth sliding contact with the first and second cam sliding faces 462 and 461 can be achieved.
Next, an actual operation of the stitch cam 25a will be described.
Figs. 7A to 7D are bottom views of the stitch cam 25a, illustrating transition states in which the pull-down amount of the second butt 14 is changed without forming any step difference.
When the stepping motor 48 is rotated forward (clockwise in Fig. 7A) from the reference position of Fig. 7A, the control cam 44 is similarly rotated forward (clockwise in Fig. 7B) in a state in which the first thickness portion 46a is clamped by the inner and outer rollers 51 and 52, as illustrated in Fig. 7B. In association with this, the distance of the first thickness portion 46a between the inner and outer rollers 51 and 52 to the center of the boss portion 47 gradually decreases, and the first cam 31 moves rearward. Also, the second cam 32 is moved rearward via the arm 33, and the pull-down amount of the second butt 14 is changed to 2 mm. At this time, the radial thickness of the first thickness portion 46a is set such that there is no step difference between the first stitch-size determining cam face 35 of the first cam 31 and the second stitch-size determining cam face 34 of the second cam 32 when the first thickness portion 46a is clamped between the inner and outer rollers 51 and 52.
Next, when the stepping motor 48 is further rotated forward from the position of Fig. 7B, the control cam 44 is similarly rotated forward in a state in which the first thickness portion 46a is clamped between the inner and outer rollers 51 and 52, as illustrated in Figs. 7C and 7D. Then, the distance of the first thickness portion 46a between the inner and outer rollers 51 and 52 to the center of the boss portion 47 gradually decreases further, and the first cam 31 and the second cam 32 move rearward. In Fig. 7C, the pull-down amount of the second butt 14 is changed to 4 mm. In Fig. 7D, the inner and outer rollers 51 and 52 are located at a terminal end of the first thickness portion 46a, and the pull-down amount of the second butt 14 is changed to 6 mm.
Figs. 8A to 8D are bottom views of the stitch cam 25a, illustrating transition states in which the pull-down amount of the second butt 14 is changed while forming a step difference S1.
As illustrated in Fig. 8A, the stepping motor 48 is rotated in reverse (counterclockwise in Fig. 8A) from the reference position so that the first cam sliding face 462 and the second cam sliding face 461 in the second thickness portion 46b are clamped by the inner and outer rollers 51 and 52 from the inner and outer sides. At this time, the inner roller 51 is pulled rearward by the second thickness portion 46b that is made thicker than the first thickness portion 46a by reduction in diameter on the inner peripheral side. For this reason, the second cam 32 is protruded frontward from the first cam 31 via the arm 33 and the second presser plate 42, and a step difference S1 is formed between the first stitch-size determining cam face 35 of the first cam 31 and the second stitch-size determining cam face 34 of the second cam 32. This can make a difference between the size of a stitch formed by the knitting needle 1 with the second butt 14 of full height and the size of a stitch formed by the knitting needle 1 with the second butt 14 of half height.
Next, as illustrated in Fig. 8B, the stepping motor 48 is further rotated in reverse to rotate the control cam 44 in reverse similarly. In association with this, the distance of the second thickness portion 46b between the inner and outer rollers 51 and 52 to the center of the boss portion 47 gradually decreases, and the first cam 31 moves rearward. Also, the second cam 32 is moved rearward via the arm 33, and the pull-down amount of the second butt 14 is changed to 2 mm while the step difference S1 remains between the first stitch-size determining cam face 35 and the second stitch-size determining cam face 34.
After that, the stepping motor 48 is further rotated in reverse from the position of Fig. 8B, and the control cam 44 is rotated counterclockwise in a state in which the second thickness portion 46b is clamped between the inner and outer rollers 51 and 52, as illustrated in Figs. 8C and 8D. Then, the distance from the second thickness portion 46b between the inner and outer rollers 51 and 52 to the center of the boss portion 47 gradually decreases further, and the first cam 31 and the second cam 32 move rearward while the step difference S1 remains between the second stitch-size determining cam face 34 and the first stitch-size determining cam face 35. At this time, in Fig. 8C, the pull-down amount of the second butt 14 is changed to 4 mm. In Fig. 8D, the inner and outer rollers 51 and 52 are located at a terminal end of the second thickness portion 46b, and the pull-down amount of the second butt 14 is changed to 6 mm.
In this way, in association with the rotation of the control cam 44, the pull-down amount of the second butt 14 of full height and half height is changed, and the step difference S1 is formed between the first stitch-size determining cam face 35 and the second stitch-size determining cam face 34. Thus, each of the left and right stitch cams 25a and 25b in the variable stitch device 25 needs one stepping motor 48. This simplifies the structure of the variable stitch device 25, and reduces the cost and the mount space of the variable stitch device 25 on the carriage.
In addition, since the control cam 44 that rotates about the boss portion 47 of the plate 45 is provided with the sliding contact portion 46 having the first and second cam sliding faces 462 and 461 on the inner and outer peripheral sides, respectively, the change of the pull-down amount of the second butt 14 of full height and half height and the change of the step difference between the first stitch-size determining cam face 35 and the second stitch-size determining cam face 34 can be performed with a simple structure. Moreover, since the inner roller 51 is supported by the second presser plate 42 (second cam 32) with the arm 33 being disposed therebetween, the second cam 32 and the inner roller 51 can be separated from each other by the arm 33.
While the embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and can be modified without departing from the scope of the invention. For example, while the substantially annular sliding contact portion 46 projects downward from the plate 45 of the control cam 44 in the embodiment, a sliding contact portion may project upward from a plate, and a first cam sliding face and a second cam sliding face may be provided on outer and inner peripheral sides of the sliding contact portion, respectively. In this case, inner and outer rollers are received in sliding contact portions of grooves provided in the plate.
While the inner and outer rollers 51 and 52 are brought into sliding contact with the first and second cam sliding faces 462 and 461 of the first and second thickness portions 46a and 46b by the biasing force of the bias spring 54 in the embodiment, inner and outer peripheral grooves for guiding inner and outer rollers may be formed by walls recessed along inner and outer peripheral sides of a projecting sliding contact portion in a manner such that the inner and outer rollers are in sliding contact with first and second cam sliding faces of first and second thickness portions. Alternatively, substantially annular sliding contact recesses may be provided in upper and lower surfaces of a plate, a first cam sliding face may be provided on one of inner and outer peripheral sides of the sliding contact recess in the upper surface, and a second cam sliding face may be provided on the other peripheral side of inner and outer peripheral sides of the sliding contact recess in the lower surface. In this case, in association with rotation of the control cam, inner and outer rollers are rolled on the second cam sliding face of the inner peripheral side of the recess and the first cam sliding face of the outer peripheral side of the recess. In these cases, a bias spring for pressing the inner and outer rollers against the first and second cam sliding faces of the first and second thickness portions is unnecessary. This further simplifies the structure of the stitch cams and reduces the cost.
While the step difference S1 is formed or nor formed by the first and second thickness portions 46a and 46b having different thicknesses in the embodiment, the two thickness portions may form different step differences. Alternatively, the sliding contact portion may have three or more thickness portions having three or more different radial thicknesses in the circumferential direction, or a thickness portion whose radial thickness changes in a stepless manner.
Further, while the inner and outer rollers 51 and 52 are in sliding contact with the first and second cam sliding faces 462 and 461 of the first and second thickness portions 46a and 46b in the sliding contact portion 46 in the embodiment, sliding contact members, such as columns or spheres that do not rotate about a shaft, may be in sliding contact with the first and second cam sliding faces, instead of the inner and outer rollers.

Claims

A flatbed knitting machine comprising a variable stitch device (25),
wherein the variable stitch device (25) includes:
a first cam (31) and a second cam (32) that move in a moving direction parallel to an inclined face of a bridge cam (23) provided on a cam plate (21) and that engage with a butt (14) whose protruding height from a needle bed is set to a full height and a half height by a press of a presser provided on a carriage to advance and retreat a knitting needle (1), the first cam (31) having a first stitch-size determining cam face (35) engageable with the butt (14) of the full height to form a large-sized stitch, the second cam (32) having a second stitch-size determining cam face (34) engageable with the butt (14) of the half height to form a small-sized stitch, the small-sized stitch and the large-sized stitch being formed in the same knitting course by forming a step difference between the first stitch-size determining cam face (35) and the second stitch-size determining cam face (34);

a control cam (44) that moves the first cam (31) and the second cam (32) in the moving direction so that the first stitch-size determining cam face (35) and the second stitch-size determining cam face (34) are switched between an even state and a stepped state; and

drive means (44) that drives the control cam (44) in a rotating direction,

wherein the control cam (44) includes a first cam sliding face (462) that moves the first cam (31) in the moving direction by sliding contact therewith via a first sliding contact member (52), and a second cam sliding face (461) that moves the second cam (32) in the moving direction by sliding contact therewith via a second sliding contact member (51), and

wherein a distance between the first cam sliding face (462) and the second cam sliding face (461) in the rotating direction of the control cam (44) differs in a plurality of steps or in a stepless manner in a circumferential direction.
The flatbed knitting machine including the variable stitch device (25) according to Claim 1,
wherein the control cam (44) includes a substantially annular projecting or recessed sliding contact portion (46) that has the first cam sliding face (462) on an outer peripheral side and the second cam sliding face (461) on an inner peripheral side and that is supported rotatably about a shaft (47) of the control cam (44), and distances between the shaft (47) and the first cam sliding face (462) and the second cam sliding face (461) are changed in association with rotation of the sliding contact portion (46) about the shaft (47), and
wherein one of the first and second sliding contact members (51, 52) is supported by the first cam (31), and the other sliding contact member is supported by one end of an arm (33) that is turnably supported at a longitudinal middle portion by the first cam (31) and is supported at the other end by the second cam (32).
The flatbed knitting machine including the variable stitch device (25) according to Claim 1 or 2,
wherein the first and second sliding contact members (51, 52) are formed by rollers.