JP2008104496A - Cloth presser foot lifting device for sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the operability, and reduce the space for a cloth presser foot lifting device. <P>SOLUTION: This cloth presser foot lifting device 1 has a cylindrical cam 30, a gear mechanism 60, an electromagnetic clutch 70 for a main shaft, an electromagnetic clutch mechanism 80 for cam shaft, a presser foot lifting switch 90, a cam position sensor 100, a pressing-foot motion detecting sensor 110, and a control section 130. In this case, the cylindrical cam 30 has an upper position guiding section 31 which guides a pressing foot 11 to an upper position H, and a lower position guiding section 32 which guides the pressing foot 11 to a lower position L. The gear mechanism 60 transmits a rotating force to the cylindrical cam 30 from a sewing machine motor 50. The electromagnetic clutch 70 for the main shaft switches the state of the transmission of the rotating force to an upper shaft 8 from the sewing machine motor 50 between a transmitted state and a non-transmitted state. The electromagnetic clutch mechanism 80 for cam shaft switches the state of the transmission of the rotating force to the cylindrical cam 30 by the gear mechanism 60 between a transmitted state and a non-transmitted state. The pressing-foot elevating switch 90 outputs a starting signal for the rotation driving of the cylindrical cam 30. The cam position detecting sensor 100 detects a specified rotating angle of the cylindrical cam 30. The presser foot motion sensor 110 detects the presence/absence of the vertical motion of the pressing foot 11. The control section 130 drives the cylindrical cam 30 in response to the input operation from the lifting switch 90. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cloth presser foot lifting apparatus for a sewing machine, and more particularly, to a cloth presser foot lifting apparatus for a sewing machine that can automatically lift and lower a lifting foot when moving the presser foot to a standby position higher than when sewing. .

Conventionally, the presser foot that holds the workpiece placed on the throat plate, the lower height (hereinafter referred to as the lower position) that holds the cloth during sewing, and when it is not sewn (for example, when taking out the workpiece) There is known a sewing machine presser foot lifting device capable of moving up and down between a height higher than that at the time of sewing (hereinafter referred to as an upper position).
Generally, when the presser foot is moved up and down between the lower position and the upper position, the operator of the sewing machine manually operates the manual operation lever or knee-lifting lever connected to the presser foot lifting mechanism for moving the presser foot up and down. (For example, refer patent document 1).
There is also known a cloth presser foot lifting device for a sewing machine configured to realize the lifting and lowering operation of the presser foot using an actuator such as a solenoid or an air cylinder (for example, see Patent Document 2).
JP 2000-93677 A Japanese Patent No. 3377324

However, in the cloth presser foot lifting apparatus disclosed in Patent Document 1, the presser foot is always biased downward by a spring, and the presser foot is located between the lower position and the upper position. When moving, there is provided a biasing direction switching mechanism that biases the presser foot downward when the presser foot is close to the lower position and biases the presser foot upward when the presser foot is close to the upper position. ing. For this reason, it is necessary to perform an operation against the urging force until the urging direction is switched, and there is a problem that the burden on the operator when operating each lever is large.
Further, in the cloth presser foot lifting device disclosed in Patent Document 2, when a solenoid is used, it is necessary to operate against the urging force, so that a large-sized one having a large thrust is required. There is a problem that it is difficult to reduce the space of the apparatus. Furthermore, when an air cylinder is used, a compressor or the like as an air supply source is required, and there is a problem that the equipment is increased in size.

  An object of the present invention is to improve the operability of the cloth presser foot lifting device in the sewing machine and to reduce the space.

  In order to solve the above-mentioned problem, the invention according to claim 1 supports the presser foot so that the presser foot can be moved up and down between a lower position for pressing the workpiece placed on the throat plate and an upper position for waiting upward when not sewing. The presser foot is lifted and lowered with a biasing direction switching means that biases the presser foot downward from a position in the middle of the lower position and biases the presser foot upward from a position in the middle of the upper position. A cylindrical cam having a mechanism, an original position having an upper position guide for guiding the presser foot to the upper position on the outer periphery and a lower position guide for guiding the presser foot to the lower position, and abutted on the original position Ascending / descending power transmission means for transmitting power for moving the presser foot to the lower position or the upper position according to the movement of the follower, and a rotational force from the sewing machine motor serving as a sewing drive source to the cylindrical cam Cam drive force transmission means for transmitting A first electromagnetic clutch that receives a signal input and switches the transmission of rotational force from the sewing machine motor to the upper shaft between a transmission state and a non-transmission state; A second electromagnetic clutch for switching transmission of rotational force to the cylindrical cam between a transmission state and a non-transmission state; cam position detection means for detecting that the cylindrical cam is positioned at a predetermined rotation angle; and Elevating / lowering input means for outputting a raising / lowering start signal for raising and lowering, and the sewing machine motor with the first electromagnetic clutch in a non-transmission state and the second electromagnetic clutch in a transmission state in response to an input operation from the elevation input means Elevating control means for driving the cylindrical cam by driving and positioning the presser foot at a lower position or an upper position based on a detection signal from the cam position detecting means. It is cloth presser foot lifting device of a sewing machine according to claim.

  According to a second aspect of the present invention, in the first aspect of the invention, manual operation means for moving the presser foot to a lower position or an upper position by an operator's manual operation is provided, and the cylindrical cam has the manual operation on an outer periphery thereof. It has a manual operation permission part which permits movement of the follower based on movement to the lower position and upper position of the presser foot by means.

  According to a third aspect of the present invention, in the second aspect of the present invention, the upper position guide portion is provided on a first half circumference of the cylindrical cam, and the lower position guide portion is provided on a second half circumference of the cylindrical cam, and the manual operation is performed. The operation allowing portion is provided between the upper position guiding portion and the lower position guiding portion, and the cam position detecting means detects a rotation angle of the cylindrical cam when the follower is positioned at the manual operation allowing portion. It is characterized by.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, when the power is turned on, the elevation control means transmits the first electromagnetic clutch in a non-transmitting state and transmits the second electromagnetic clutch. The cylindrical cam is driven by driving the sewing machine motor as a state, and the follower is disposed in the manual operation permission portion based on a detection signal from the cam position detecting means.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, further comprising operation detecting means for detecting presence or absence of an up-and-down movement operation of the presser foot, wherein the elevating control means is Based on the motion detection means and the cam position detection means, when an input operation is performed from the lifting input means when the presser foot is disposed at the lower position, the presser foot is moved to the upper position. The sewing machine motor is driven, and the sewing machine motor is driven until the presser foot is moved to the lower position when an input operation from the lifting input means is performed when the presser foot is disposed at the upper position. It is characterized by that.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the apparatus according to the fifth aspect further includes warning means for notifying a user of malfunction, and the lift control means is provided for a predetermined period after power-on or after an input operation from the lift input means. When the detection signal from either one of the motion detection means or the cam position detection means is not detected after elapse of time, a control process for operating the warning means is performed.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the cylindrical cam has a needle plate of a presser foot by an urging force of the urging direction switching means at its original node. It has the buffer guide part which prevents the collision with respect to.

According to the first aspect of the present invention, when input from the lifting input means is performed, the lifting control means switches the first electromagnetic clutch to the non-transmitting state and the second electromagnetic clutch to the transmitting state, and the sewing machine motor Is driven to rotate the cylindrical cam. And if a follower moves along the upper position guide part of the said cylindrical cam, motive power will be transmitted to a holding foot raising / lowering mechanism via a raising / lowering power transmission means, and a holding foot will be arrange | positioned in an upper position. When the follower moves along the lower position guide portion of the cylindrical cam, power is transmitted to the presser foot lifting mechanism via the lift power transmission means, and the presser foot is disposed at the lower position. In other words, the operator of the sewing machine can simply lift and lower the presser foot to the upper position or the lower position simply by performing an input operation from the lifting input means without requiring a large force to resist the biasing force of the biasing direction switching means. Can be made. Further, by rotating the cylindrical cam using a sewing motor having a large rotational force as a drive source, a large thrust for raising and lowering the presser foot can be obtained. As a result, the lifting and lowering operation of the presser foot can be performed smoothly, and a large actuator with a large thrust is not required separately for lifting and lowering the presser foot, thereby reducing the space of the device.
Further, since the cam position detecting means can detect that the cylindrical cam is positioned at the predetermined rotation angle, for example, the rotation angle of the cylindrical cam when the presser foot is disposed at the lower position or the upper position is set to the predetermined rotation angle. By setting to, the lifting control means can automatically execute control for arranging the presser foot at the upper position or the lower position, and the operability can be improved.

  According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained. In particular, when the follower is disposed in the manual operation allowing portion of the cylindrical cam, the manual operation means is provided. The operator can manually move the presser foot to the lower position or the upper position via the. Therefore, the freedom degree of operativity of the cloth presser foot lifting apparatus of the sewing machine is improved.

  According to the third aspect of the present invention, the same effect as that of the second aspect of the invention can be obtained. By providing this, the presser foot can be arranged at the upper position or the lower position by at least rotational driving within one turn of the cylindrical cam. In addition, since the cam position detection means can detect the rotation angle of the cylindrical cam when the follower is positioned at the manual operation permission portion provided between the upper position guide portion and the lower position guide portion, for example, Based on the detection signal from the cam position detecting means, the lifting control means stops the sewing machine motor or puts the second electromagnetic clutch in a non-transmitting state so that the presser foot is arranged at the lower position or the upper position. be able to.

  According to the invention described in claim 4, in addition to obtaining the same effect as that of the invention described in claim 2 or claim 3, in particular, when the power of the sewing machine is turned on, the lift control means Control is performed to drive the cylindrical cam until the cam position detecting means detects that the manual operation permission portion has rotated to the position where the follower is disposed. Further, when the rotation angle of the cylindrical cam detected by the cam position detecting means is set to the rotation angle of the cylindrical cam when the follower is disposed between the upper position guide portion and the lower position guide portion, for example. Can automatically place the presser foot in either the upper or lower position when the power is turned on.

  According to the fifth aspect of the present invention, the same effect as that of any one of the first to fourth aspects of the present invention can be obtained. The presser foot is placed in the lower position by driving the cylindrical motor with the first electromagnetic clutch in the non-transmitting state and the second electromagnetic clutch in the transmitting state until the vertical movement is detected. When an input operation is performed from the lifting input means, the cylindrical cam is driven until the presser foot moves to the upper position, and the above input operation is performed when the presser foot is disposed at the upper position. When this is performed, a control process for driving the cylindrical cam is performed until the presser foot moves to the lower position. Thus, the vertical position of the presser foot can be automatically switched by performing an input operation from the lifting input means, and the switching is performed when the lifting control means stops the rotation of the cylindrical cam based on the cam position detecting means. The presser foot can be held at the raised position. Therefore, the operability of the presser foot lifting device for the sewing machine can be improved.

  According to the sixth aspect of the present invention, the same effect as that of the fifth aspect of the invention can be obtained, and in particular, a predetermined period of time can be obtained after the power is turned on or after the input operation from the lift input means by the lift control means. If the detection signal from the motion detection means or the cam position detection means is not detected when the time has elapsed, a control process for notifying the user of the malfunction is performed by the warning means. Thereby, the user of the sewing machine can detect a malfunction, that is, an abnormality of the presser foot lifting mechanism, the motion detection unit, or the cam position detection unit.

  According to the seventh aspect of the invention, the same effect as that of any one of the first to sixth aspects can be obtained, and in particular, the follower abutted against the original joint of the cylindrical cam. Therefore, the presser foot can be moved to the lower position while preventing the presser foot from colliding with the needle plate due to the biasing force of the biasing direction switching means. This prevents the presser foot or the needle plate from being damaged due to the collision between the presser foot and the needle plate, and also prevents the sewing product from being damaged on the needle plate by the presser foot to prevent the sewing quality. Can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples. In the present embodiment, the direction of each part of the sewing machine is determined based on the XYZ axes shown in the drawings. In a state where the sewing machine is installed on a horizontal plane, the Z-axis direction indicates the vertical direction that is the vertical direction, the Y-axis direction indicates the left-right direction that coincides with the longitudinal direction of the sewing machine arm portion 3, the X-axis direction is horizontal and the Y-axis direction The front-rear direction orthogonal to is shown.

(overall structure)
As shown in FIGS. 1 to 3, the sewing machine cloth presser foot lifting device 1 (hereinafter simply referred to as a presser foot lifting device 1) in the present embodiment is a cloth that is a sewing product placed on a needle plate 9. A presser foot lifting mechanism 10 that supports the presser foot 11 so as to be lifted up and down at a lower position L that presses down and an upper position H that waits upward when not sewing, and the presser foot 11 is moved to a lower position L and an upper position H by an operator's operation. A manual operation mechanism 20 as a manual operation means to be moved to an upper position, an upper position guide portion 31 (see FIG. 5) for guiding the presser foot 11 to the upper position H on the outer periphery, and a lower position guide portion 32 for guiding the presser foot 11 to the lower position L. (Refer to FIG. 5), and the presser foot 11 is moved to the lower position L or the presser foot elevating mechanism 10 according to the movement of the cylindrical cam 30 having the original node and the cam follower 41 which is a follower contacted with the original node. Transmits power to move to the upper position H A link mechanism 40 as a descending power transmission means, a gear mechanism 60 as a cam driving force transmission means for transmitting a rotational force from the sewing machine motor 50 as a sewing drive source to the cylindrical cam 30, and a sewing machine that receives an input of a control signal The main shaft electromagnetic clutch 70 as a first electromagnetic clutch for switching the transmission of the rotational force from the motor 50 to the upper shaft 8 between the transmission state and the non-transmission state, and the cylindrical cam 30 by the gear mechanism 60 upon receiving a control signal As a second electromagnetic clutch 80 for switching the transmission of the rotational force between the transmission state and the non-transmission state, and as a lifting input means for outputting a start signal for lifting and lowering the presser foot 11 Presser foot lift switch 90, cam position detection sensor 100 as cam position detecting means for detecting that the cylindrical cam 30 is positioned at a predetermined rotation angle, and a presser In response to an input operation from the presser foot lift switch 90, an alarm lamp 120 as a warning means for notifying the user of a malfunction, And a control unit 130 (see FIG. 6) as a lifting control means for driving the sewing machine motor 50 and arranging the presser foot 11 at the lower position L or the upper position H based on the detection signal from the cam position detection sensor 100. Yes. Hereinafter, each part will be described in detail.

As shown in FIGS. 2 and 3, the presser foot lifting mechanism 10 includes a presser foot 11 that presses the cloth placed on the needle plate 9 from above, a presser bar 12 that supports the presser foot 11 at the lower end, A presser bar holder 13 having an extending portion that is fixed to the presser bar 12 and extending in the horizontal direction, a presser spring 19 that constantly urges the presser bar 12 downward, and a presser foot 11 from a position in the middle toward the lower position L. And an urging direction switching mechanism 14 as urging direction switching means for urging the presser foot 11 upward from a position on the way to the upper position H.
The presser foot 11 is supported by the lower end of a presser bar 12 supported at the tip of the sewing machine arm 3 so as to be movable up and down. During sewing, the presser foot 11 responds to the rotation of the upper shaft 8 rotated by a sewing machine motor 50 described later. The vertical movement is performed in the vicinity of the lower position L in synchronization with a needle drive mechanism (not shown). In addition, the presser foot 11 is retracted to an upper position H above the height near the lower position L, which is the vertical movement range during the sewing, for example, when not being sewn, such as when taking out the workpiece, and will be described later. It is possible to move to an uppermost position T that is further above the upper position H via the manual operation mechanism 20 that performs the above operation. The uppermost position T is a position at which the presser foot 11 can be lifted by lifting the manual operation lever 21 (to be described later) against the biasing force of the presser spring 19. When the object is placed on or removed from the throat plate 9, it serves as a retracting portion for releasing the presser foot 11 upward. The presser foot 11 is raised to the uppermost position T by the operator's manual operation and then lowered to be placed at the upper position H when the operator releases the manual operation lever 21.
The presser bar 12 is equipped with a presser spring 19 that is a coiled compression spring. The upper end of the presser spring 19 is locked by a locking member 17 fixed to the sewing machine arm 3, and the lower end is held by a presser bar. 13 is locked to the upper surface.
The urging direction switching mechanism 14 has a protrusion 16 that is rotatably supported by the sewing machine arm 3 via a shaft 15. The protrusion 16 is provided at a base end portion of a manual operation lever 21 to be described later, and supports the presser bar holder 13 that is always urged downward by the urging force of the presser spring 19 to support the presser foot 11 from below. Defines the height. That is, when the manual operation lever 21 is disposed at the lower position L, the left inclined portion of the projection 16 in FIG. The holding bar holder 13 is supported at the height to be arranged. Here, when the manual operation lever 21 is rotated counterclockwise in FIG. 2 and moved to the upper position H, the apex of the protrusion 16 is moved along the lower surface of the presser bar holder 13 and the protrusion When the right inclined portion of 16 approaches the lower surface of the presser bar holder 13, the presser bar holder 13 is constantly biased downward, so that the right inclined portion is in contact with the lower surface of the presser bar holder 13, that is, The urging direction is switched in the direction in which the presser foot 11 is disposed at the upper position H. Further, when the manual operation lever 21 is rotated clockwise and moved to the lower position L, the apex of the protrusion 16 is moved along the lower surface of the presser bar holder 13, and the left side of the protrusion 16 When the inclined part of the holding bar approaches the lower surface of the presser bar holder 13, the biasing direction is switched to the direction in which the left inclined part is in contact with the lower surface of the presser bar holder 13, that is, the direction in which the presser foot 11 is disposed at the lower position L. It will be. The presser foot 11 is maintained at the lower position L or the upper position H with a predetermined holding force.

  The manual operation mechanism 20 includes a manual operation lever 21 that raises and lowers the presser foot 11 by an operator's manual operation, and a knee lift lever (not shown) that raises and lowers the presser foot 11 by an operator's knee operation. As shown in FIGS. 2 and 3, the manual operation lever 21 is provided on the other end side of the protrusion 16 via a shaft 15 and extends below the sewing machine arm 3. Further, a presser foot elevating link 25 is rotatably connected to the manual operation lever 21 via an arm member 24 fixed to the shaft 15. Then, the presser foot lifting link 25 is moved to the vertical trunk portion side (the right side in FIG. 2) so that the presser foot 11 is arranged at the lower position L. ), The presser foot 11 is arranged at the upper position H.

Next, based on FIG.1, FIG4 and FIG.5, the structure of the cylindrical cam 30 in this embodiment is demonstrated in detail.
As shown in FIGS. 1 and 4, the cylindrical cam 30 is a substantially cylindrical rotating body having a groove on the outer periphery, and the sewing machine arm portion 3 has a thrust direction parallel to the upper shaft 8, that is, along the Y-axis direction. It is arranged in the inside. The cylindrical cam 30 is fixed to a cam shaft 35 provided in parallel with the upper shaft 8 at the shaft center, and is provided so as to be rotatable only in the direction of arrow C shown in FIGS. It has been.
As shown in FIG. 5, the cylindrical cam 30 has an upper position guide portion 31 for guiding the presser foot 11 to the upper position H, a lower position guide portion 32 for guiding the lower foot L to the lower position L, as described above. A manual operation permission portion 34 that allows movement of a cam follower 41 (described later) based on the movement of the presser foot 11 to the lower position L and upper position H by the manual operation mechanism 20, and the presser foot 11 by the biasing force of the biasing direction switching mechanism 14. And a buffer guide portion 33 for preventing a collision with the needle plate 9.

  The upper position guide portion 31 is provided over a half circumference of the outer periphery of the cylindrical cam 30. For example, when the cam follower 41 (described later) is guided with the upper position guide portion 31 as an original clause, the cylindrical cam The presser foot 11 can be raised from the lower position L to the upper position H by rotating 30 by 180 ° in the direction of arrow C. Specifically, as shown in FIG. 5, the upper position guide portion 31 is moved from the edge of the cylindrical cam 30 on the vertical trunk portion side (right side in FIG. 5) to the sewing machine head side (in accordance with the rotation of the cylindrical cam 30). It is a convex guide portion formed on the outer periphery of the cylindrical cam 30 so as to guide the cam follower 41 to a position about half of the length of the cylindrical cam 30 in the thrust direction. In the present embodiment, the state where the cam follower 41 is disposed on the front side of the rising start position of the upper position guide portion 31 is defined as the 0 ° position of the cylindrical cam 30.

  When the above-described upper position guide portion 31 is provided on the first half circumference (for example, 0 ° to 180 °) of the cylindrical cam 30, the lower position guide portion 32 has a second half circumference (for example, 180 ° to 360 °). Contrary to the above-described upper position guide portion 31, the lower position guide portion 32 extends from the edge of the cylindrical cam 30 on the sewing machine head side (left side in FIG. 5) to the vertical barrel portion according to the rotation of the cylindrical cam 30. The cam follower 41 is guided toward the side (right side) of the cylindrical cam 30 to a position that is about a half of the length of the cylindrical cam 30 in the thrust direction, and becomes a convex guide portion formed on the outer periphery of the cylindrical cam 30. ing. As shown in FIG. 5, the lower position guide portion 32 in the present embodiment is formed from the edge of the cylindrical cam 30 on the sewing machine head side when the rising start position is approximately 180 ° of the cylindrical cam 30. Thus, the cam follower 41 is prevented from moving when the presser foot 11 is raised to the uppermost position T.

  As shown in FIG. 5, the buffer guide portion 33 is provided in the range of 180 ° to 360 ° (0 °) of the cylindrical cam 30, and the outer periphery of the cylindrical cam 30 is opposite to the lower position guide portion 32. It is a convex guide formed at the end, that is, at the end of the vertical body. The buffer guide portion 33 has a curved shape in which the end face serving as the original node has a vertex in the vicinity of 270 ° of the cylindrical cam 30, and the biasing direction switching mechanism 14 described above in the range of 270 ° to 360 ° (0 °). The cam follower 41 that is separated from the lower position guide portion 32 by the urging force is gently guided to the edge on the vertical trunk portion side corresponding to the lower position L of the presser foot 11. As is clear from FIG. 5, the buffer guide portion 33 has the cam follower 41 in the vicinity of the edge on the vertical trunk portion side when the presser foot 11 is disposed at the lower position L when the cylindrical cam 30 is 180 °. Also in the position, the cam follower 41 smoothly passes over the buffer guide portion 33 as the cylindrical cam 30 rotates, and when the cylindrical cam 30 rotates to 360 ° (0 °), the presser foot 11 is moved to the lower position L. It can be guided smoothly.

  As shown in FIG. 5, the manual operation permission portion 34 is provided between the upper position guide portion 31 and the lower position guide portion 32 described above, that is, at two positions of 0 ° (360 °) and 180 ° on the outer periphery of the cylindrical cam 30. Are provided respectively. The manual operation permission portion 34 allows the operator of the sewing machine to operate the manual operation lever 21 or the knee raising lever described above. By operating the manual operation lever 21 or the knee raising lever, the presser foot 11 can be operated. This is to allow the cam follower 41 to move in the thrust direction of the cylindrical cam 30 via the link mechanism 40 described later when moving to the lower position L, the upper position H, or the uppermost position T.

As shown in FIG. 1, the link mechanism 40 has a first link 42 whose substantially central portion in the longitudinal direction is rotatably supported by the sewing machine frame, and one end pivoted at one end (upper end) of the first link 42. One end of the second link 43 that is freely connected and the other end of the second link 43 are rotatably connected, and the sewing machine frame is rotatable about the fulcrum shaft 44a at a substantially central portion in the longitudinal direction. The third link 44 is connected to the other end of the presser foot lifting link 25 of the presser foot lifting mechanism 10 described above and is rotatably connected to the other end.
At the other end of the first link 42, a cam follower 41, which is a follower that is in contact with each of the original nodes 31, 32, 33 of the cylindrical cam 30, is attached to the surface facing the outer periphery of the cylindrical cam 30. The cam follower 41 has an outer periphery of the cylindrical cam 30 substantially along the thrust direction from the one end (the left end in FIG. 1) to the other end in accordance with the movement of the first link 42 swinging left and right in FIG. 1 about the fulcrum shaft 42a. It can move within the range up to (the right end).

  When the cam follower 41 is guided along the upper position guide portion 31 as the cylindrical cam 30 rotates, one end (the upper end in FIG. 1) of the first link 42 is centered on the fulcrum shaft 42a. The first link 42 is swung in the same direction as the one end side of the first link 42 via the second link 43. Thereby, the other end (lower end in FIG. 1) of the third link 44 is swung in the front-rear direction around the fulcrum shaft 44a. That is, when the upper end of the first link 42 swings to the right side in FIG. 1, the lower end of the third link 44 swings to the left side via the second link 43. The driving force toward the upper position H is transmitted to the presser foot 11. Conversely, when the cam follower 41 is guided along the lower position guide portion 32, the upper end of the first link 42 is swung around the fulcrum shaft 42 a in the direction of arrow E, and the third link is passed through the second link 43. Since the lower end of the link 44 is swung to the right side, the presser foot lifting link 25 is moved to the machine longitudinal trunk side, and the driving force toward the lower position L is transmitted to the presser foot 11. Thus, the power for raising and lowering the presser foot 11 is transmitted from the cam follower 41 to the presser foot lifting link 25 via the first link 42, the second link 43 and the third link 44.

  The sewing machine motor 50 is a driving source of the sewing machine that is disposed below the sewing machine bed and applies rotational force to the upper shaft 8 in the sewing machine arm portion 3 via the motor belt 51 and the motor pulley 52 shown in FIG. The sewing machine motor 50 is freely driven or stopped in a predetermined direction (in this embodiment, a direction in which the motor pulley 52 rotates in the direction of arrow B shown in FIG. 1) in accordance with an output signal from the control unit 130 described later. It is possible to do.

  As shown in FIG. 1, the gear mechanism 60 includes a motor pulley gear 61 formed integrally with the motor pulley 52, and a cam gear 62 that meshes with the motor pulley gear 61 on the outer periphery. The gear mechanism 60 is for transmitting the rotational force transmitted from the sewing machine motor 50 to the motor pulley 52 via the motor belt 51 to the cylindrical cam 30, and meshes with the motor pulley gear 61 that rotates in the direction of arrow B. The cam gear 62 applies a rotational force in the direction of arrow C to the cam shaft 35 that supports the cylindrical cam 30.

  The main shaft electromagnetic clutch 70 is provided on the upper shaft 8, which is the main shaft of the sewing machine, and is arranged in parallel with the motor pulley gear 62 fixed to the upper shaft 8. Is provided. The main shaft electromagnetic clutch 70 can be switched ON / OFF in accordance with an output signal from the control unit 130 described later, that is, a control signal, and transmits rotational force between one end side and the other end side of the upper shaft 8. It is configured to be switchable between a transmission state in the ON state and a non-transmission state in the OFF state. The rotational force transmitted from the sewing machine motor 50 to the motor pulley 52 is transmitted to the distal end side (the left side in FIG. 1) of the upper shaft 8 only when connected in the ON state. Therefore, when the main shaft electromagnetic clutch 70 is OFF, a rotational force is applied from the end of the upper shaft 8 connected to the motor pulley 52 on the vertical trunk portion side to the end of the upper shaft 8 on the sewing machine head side. Not provided, the upper shaft 8 is in a stopped state.

  The cam shaft electromagnetic clutch 80 is provided on the cam shaft 35 provided in parallel with the upper shaft 8, and is provided in parallel with the cam gear 62. Similar to the main shaft electromagnetic clutch 70, the cam shaft electromagnetic clutch 80 can be switched ON / OFF according to an output signal from the control unit 130, which will be described later, that is, one end side of the cam shaft 35. And the other end side can be switched between the transmission state in the ON state and the non-transmission state in the OFF state. Only when the rotational force transmitted from the sewing machine motor 50 to the camshaft gear 62 via the motor belt 51, the motor pulley 52, and the motor pulley gear 61 is coupled in the ON state (see FIG. 1). To the left). Therefore, when the camshaft electromagnetic clutch 80 is OFF, no rotational force is applied from the camshaft 35 on the cam gear 62 side to the cylindrical cam 30, and the cylindrical cam 30 is stopped.

  As shown in FIG. 3, the presser foot raising / lowering switch 90 is a push button type input switch disposed on the head of the sewing machine. An output signal, that is, a start signal for starting a lifting operation for lifting the presser foot 11 by rotating the cylindrical cam 30 in the direction of arrow C is transmitted (see FIG. 6).

As shown in FIGS. 1 and 4, the cam position detection sensor 100 includes a substantially disc-shaped cam position detection plate 101 fixed to the cam shaft 35 and slits 101 a and 101 b formed in the cam position detection plate 101. It comprises the sensor part 102 to detect.
The slits 101 a and 101 b are provided at the edge of the cam position detection plate 101, and are provided at target positions with respect to the cam shaft 35. In the present embodiment, when the cam follower 41 is disposed at the position where the slit 101a is at 0 ° (360 °) of the cylindrical cam 30, that is, the manual operation permission portion 34 on the front side of the rising start position of the upper position guide portion 31. Corresponding to the rotation angle of the cylindrical cam 30, the cam follower 41 is located at a position where the other slit 101 b is 180 ° of the cylindrical cam 30, that is, the manual operation permission portion 34 between the end of the upper position guide portion 31 and the lower position guide portion 32. This corresponds to the rotation angle of the cylindrical cam 30 when it is disposed.
That is, the cam position detection sensor 100 detects the rotation angle of the cylindrical cam 30 when the cylindrical cam 30 is provided at a predetermined rotation angle, that is, when the cam follower 41 is disposed in any one of the manual operation permission portions 34. ing.
The sensor unit 102 includes, for example, a photosensor having a light receiving unit and a light emitting unit, and the slit 101 a or 101 b of the cam position detection plate 101 that rotates about the cam shaft 35 is a detection unit of the sensor unit 102. It is OFF when it is placed in the position, and ON otherwise. And the ON / OFF signal detected by this sensor part 102 is transmitted to the control part 130 mentioned later at any time.

The presser foot motion detection sensor 110 includes a presser foot raising detection plate 111 fixed to one end of the upper portion of the presser bar 12 and a sensor portion having a slit, that is, a detection portion, which is fixed in a sewing machine arm portion and through which the presser foot raising detection plate 111 passes. 112. The presser foot raising detection plate 111 moves up and down integrally with the presser bar 12 according to the lifting and lowering operation of the presser foot 11. The sensor unit 112 includes, for example, a photosensor or the like, similar to the sensor unit 102 described above.
Then, depending on whether the presser foot rise detection plate 111 is disposed on the detection unit of the sensor unit 112 or not, a detection signal of either ON / OFF is transmitted from the sensor unit 112 to the control unit 130 described later. It has become so. In other words, the presser foot motion detection sensor 110 is used when the presser foot 11 is raised from the lower position L or an intermediate position between the lower position L and the upper position H to the upper position H, or from the upper position H to other than the upper position H. Is detected in the position (including the lower position L), whether or not the vertical position of the presser foot 11 has changed, that is, whether the presser foot 11 has actually moved up or down. Is detected.

  As shown in FIG. 3, the alarm lamp 120 is provided in the vicinity of the presser foot raising / lowering switch 90 described above in the head of the sewing machine. The alarm lamp 120 is lit in response to a control signal from the control unit 130, which will be described later, to notify the operator of the sewing machine of a malfunction. In the present embodiment, in particular, detection signals from the cam position detection sensor 100 or the presser foot movement detection sensor 110 described above after the elapse of a predetermined period after the sewing machine is turned on or during various control processes to be described later by the control unit 130. It is turned on when no change is confirmed.

  Next, based on FIG. 6, the structure of the control part 130 in this embodiment is demonstrated. FIG. 6 is a block diagram showing a control system circuit in the present embodiment. As shown in FIG. 6, the control unit 130 is a microcomputer including a CPU 131 and a ROM, RAM, EEPROM, etc. (not shown). On the input side of the CPU 31 is a presser foot lifting switch 90, a cam position detection. Output signals from the sensor 100 and the presser foot motion detection sensor 110 are input. Further, on the output side of the CPU 31, a sewing machine motor driving circuit 132 for driving the sewing machine motor 50, a main shaft electromagnetic clutch driving circuit 133 for driving the main shaft electromagnetic clutch 70, and a cam for driving the cam shaft electromagnetic clutch 80 are provided. The shaft electromagnetic clutch drive circuit 134 and the alarm lamp 120 are connected.

The control unit 130 in the present embodiment drives the sewing machine motor 50 with the main shaft electromagnetic clutch 70 in a non-transmitting state and the camshaft electromagnetic clutch 80 in a transmitting state in response to an input operation from the lifting input means. Control is performed to drive the cam 30 and to arrange the presser foot 11 at the lower position or the upper position based on the detection signal from the cam position detection sensor 100.
Further, the control unit 130 determines the presser foot lift switch 90 when the presser foot 11 is disposed at the lower position L based on the detection signal from the presser foot motion detection sensor 110 and the detection signal from the cam position detection sensor 100. When the presser foot 11 is moved to the upper position H, the sewing machine motor 50 is driven. When the presser foot 11 is arranged at the upper position H, the presser foot lift switch 90 When an input operation is performed, a control process for driving the sewing machine motor 50 until the presser foot 11 is moved to the lower position L is performed.
Further, the control unit 130 performs a control process of driving the sewing machine motor 50 when the power is turned on and arranging the cam follower 41 in the manual operation permission unit 34 based on a detection signal from the cam position detection sensor 100.
In addition, the control unit 130 does not detect a detection signal from either the presser foot motion detection sensor 110 or the cam position detection sensor 100 after a predetermined period of time has elapsed after power-on or after an input operation from the presser foot lift switch 50. In this case, a control process for operating the alarm lamp 120 is performed.

(Description of operation of embodiment)
Next, based on the flowchart shown in FIG. 7, operation | movement of the cloth presser foot raising / lowering apparatus 1 of a sewing machine provided with the said structure is demonstrated.
First, when the presser foot lift switch 90 is pressed by the operator of the sewing machine (step S1), the CPU 131 determines whether or not the sewing machine motor 50 is stopped based on the detection signal (step S2). When it is not confirmed that the sewing machine motor 50 is stopped (step S2; No), the CPU 131 waits for an input from the presser foot lifting switch 90 again. On the other hand, when it is confirmed in step S2 that the sewing machine motor 50 is stopped (step S2; Yes), the CPU 131 outputs a non-excitation signal via the main shaft electromagnetic clutch drive circuit 133, and the main shaft electromagnetic By turning off the clutch 70, the transmission of the rotational force from the sewing machine motor 50 to the upper shaft 8 is switched to the non-transmission state, and at the same time, an excitation signal is output via the cam shaft electromagnetic clutch drive circuit 134, A control process for switching the transmission of the rotational force from the cam gear 62 to the cylindrical cam 30 to the transmission state by turning on the electromagnetic clutch 80 is performed (step S3).

Next, CPU 131, through the sewing machine motor driver circuit 132 starts driving of the sewing machine motor 50 (step S4), and starts the internal timer _{t 1} after an internal timer _{t 1} and _{t 2} is reset (step S5) (Step S6).
The internal timer t _1, by detecting signals from the presser foot rise detection sensor 110 determines whether a change within a predetermined time period from the start of the control process (time), for example, the presser foot 11 This is for detecting a detection failure of the presser foot rise detection sensor 110 due to a lifting / lowering operation failure or a disconnection or the like to stop the rotational drive of the sewing machine motor 50 in a certain time. The internal timer t _2, by determining whether an OFF signal from the cam position detection sensor 100 is detected within the predetermined time period from the start of the control process, for example, rotation failure or disconnection of the cylindrical cam 30 For example, a detection failure of the cam position detection sensor 100 due to the above is detected, and the rotational drive of the sewing machine motor 50 is stopped in a certain time. These internal timers t ₁ and t ₂ can be set in advance to desired times. In this case, it is desirable that t ₁ and t ₂ are set to a time during which the cylindrical cam 30 can rotate at least _once , that is, 360 ° or more by the rotational drive of the sewing machine motor 50. As is apparent from FIG. 5, according to the cylindrical cam 30 in the present embodiment, the presser foot 11 is in either the lower position L or the upper position H while the cylindrical cam 30 makes at least one round (360 °). When the position of the detection signal from the presser foot raising detection sensor 110 does not change during rotation about half a circle (180 °) (for example, from the upper position H at 0 ° by manual operation). The case where the vehicle is started or the vehicle is disposed at the lower position L at 180 ° is taken into consideration.

Next, the process proceeds to step S7. In step S7, the CPU 131 determines whether or not it has been detected that the signal from the presser foot rise detection sensor 110 has changed, that is, whether the presser foot 11 has actually been raised or lowered (step S7). When the detection signal from the presser foot rise detection sensor 110 has changed (step S7; Yes) i.e. if it is confirmed that the presser foot 11 has actually operated (rising or falling), CPU 131 may start an internal timer _{t 2} In step S10, it is determined whether the cam position detection sensor 100 is OFF (step S11).
On the other hand, if the detection signal from the presser foot rise detection sensor 110 does not change in step S7 (step S7; No), that is, if it is not yet confirmed that the presser foot 11 has actually operated (raised or lowered), the CPU 131 it is judged whether or not the internal timer t ₁ has reached the set value (step S8). When the internal timer t ₁ has not reached the set value (step S8; No), the CPU131 is whether the detection signal from the foot rising detection sensor 110 presser moves is changed to step S7 again determined Do.

Here, the processing in steps S7 and S8 is to determine whether the cylindrical cam 30 is rotated 180 ° or 360 ° in the process in which the cylindrical cam 30 is rotated by the rotational drive of the sewing machine motor 50. That is, for example, when the presser foot 11 is disposed at the lower position L when the cylindrical cam 30 is at 0 ° (see FIG. 9A), or when the presser foot 11 is at the upper position when the cylindrical cam 30 is 180 °. When it is arranged at the position H (see FIG. 9B), the height of the presser foot 11 changes when the cylindrical cam 30 is rotated by 180 °. When the presser foot 11 is disposed at the upper position H at the position of 0 ° (see FIG. 9C), or the presser foot 11 is disposed at the lower position L when the cylindrical cam 30 is at the position of 180 °. In this case (see FIG. 9D), the rotation of the cylindrical cam 30 does not change in the height of the presser foot 11 because the rotation of the cylindrical cam 30 is 180 °, and therefore it is necessary to further rotate 180 ° (that is, 360 ° in total). .
That is, according to steps S7 and S8, when the presser foot 11 is arranged at the lower position L when the presser foot raising / lowering switch 90 is pressed, the sewing machine motor 50 is driven until it is arranged at the upper position H. On the contrary, when the presser foot 11 is arranged at the upper position H when the presser foot raising / lowering switch 90 is pressed, a control process for driving the sewing machine motor 50 until it is arranged at the lower position L is performed. . As a result, the operator of the sewing machine can switch the presser foot when he / she wants to switch the position where the presser foot 11 is currently arranged, regardless of whether the presser foot 11 has been raised or lowered manually by the manual operation lever 21 or the knee-lifting lever. If the up / down switch 90 is pressed, it can be automatically switched without manual operation.
When it is determined to have reached the set value of the internal timer t ₁ in step S8 (Step S8; Yes), it foot 11 pressing be rotated cylindrical cam 30 is 360 ° or more is not performed lifting operations Alternatively, in order to mean a rotation failure of the cylindrical cam 30, the CPU 131 turns on the alarm lamp 120 (step S9), notifies the operator of the operation failure, and then proceeds to step S11.

Next, in step S11, the CPU 131 determines whether or not the cam position detection sensor 100 is OFF (step S11).
Here, the determination in step S11 is whether or not any one of the slits 101a and 101b provided in the cam position detection plate 101 is arranged at a position detected by the sensor unit 102, that is, a cylinder. By determining whether the cam 30 is disposed at 0 ° or 180 °, it is determined whether the presser foot 11 is disposed at the lower position L or the upper position H.
In step S11, when an OFF signal is detected from the cam position detection sensor 100 (step S11; Yes), the CPU 131 stops (OFF) the sewing machine motor 50 (step S14), and then the camshaft electromagnetic clutch drive circuit. The non-excitation signal is output via 134 and the camshaft electromagnetic clutch 80 is turned OFF, so that the transmission of the rotational force from the cam gear 62 to the cylindrical cam 30 is switched to the non-transmitting state, and at the same time, the main shaft electromagnetic clutch drive circuit The excitation signal is output via 133, and the transmission of the rotational force from the sewing machine motor 50 to the upper shaft 8 is switched to the transmission state by switching the main shaft electromagnetic clutch 70 to ON (step S15), and the process is terminated. As a result, when the sewing machine motor 50 rotates, the rotational force is transmitted to the tip of the upper shaft 8, and the sewing machine 50 is ready for sewing.
On the other hand, if the OFF signal from the cam position detection sensor 100 is not detected in step S11 (step S11; No), CPU 131 performs the determination of whether the internal timer _{t 2} reaches the set value (step S12). When the internal timer _{t 2} is less than the set value (step S12; No), the process proceeds to step S11 again. On the other hand, if the internal timer _{t 2} reaches the set value (step S12; Yes), CPU 131 causes the light the alarm lamp 120 (step S13), and after the sewing machine motor 50 is stopped (OFF) (step S14) camshaft At the same time when the electromagnetic clutch 80 is switched off, the main shaft electromagnetic clutch 70 is switched on and the process is terminated (step S15).

Next, the operation of the presser foot lifting apparatus 1 when the power is turned on will be described based on the flowchart shown in FIG.
When the power is turned on (step S20), the CPU 131 first outputs an excitation signal via the main shaft electromagnetic clutch circuit 133, turns on the main shaft electromagnetic clutch 70, and turns the rotational force from the sewing machine motor 50 to the upper shaft 8. The control process for setting the transmission of the transmission to the transmission state is performed (step S21). This is for keeping the rotational force of the sewing machine motor 50 to be transmitted to the upper shaft 8 as an initial process when the power is turned on. Next, the CPU 131 determines whether or not the cylindrical cam 30 is disposed at 0 ° or 180 ° by determining whether or not the detection signal from the cam position detection sensor 100 is OFF ( If the detection signal is OFF (step S22; Yes), that is, if the presser foot 11 is disposed at either the lower position L or the upper position H, the process ends. On the other hand, if the detection signal from the cam position detection sensor 100 is not OFF (step S22; No), that is, for example, the presser foot lifting / lowering operation is interrupted halfway due to a power failure or the like. And the upper position H, the CPU 131 outputs a non-excitation signal via the main shaft electromagnetic clutch drive circuit 133 and turns off the main shaft electromagnetic clutch 70 to turn the upper shaft 8 from the sewing machine motor 50. At the same time as the transmission of the rotational force to the non-transmission state is switched, an excitation signal is output via the camshaft electromagnetic clutch drive circuit 134, and the camshaft electromagnetic clutch 80 is turned on to turn on the cylindrical cam 30. A control process for switching the transmission of the rotational force to the transmission state is performed (step S23).

Next, the CPU 131 rotates the sewing machine motor 50 through the sewing machine motor drive circuit 132 (step S24), resets the internal timers t ₁ and t ₂ (step S25), and starts the internal timer t ₂ (step S25). S26), it is determined whether or not the detection signal from the cam position detection sensor 100 is OFF (step S27).
In step S27, when the detection signal from the cam position detection sensor 100 is OFF (step S27; Yes), that is, when the presser foot 11 is disposed at either the lower position L or the upper position H, the CPU 131 After stopping (OFF) the sewing machine motor 50 via the drive circuit 132 (step S30), a non-excitation signal is output via the camshaft electromagnetic clutch drive circuit 134 to turn off the camshaft electromagnetic clutch 80. At the same time, the transmission of the rotational force from the cam gear 62 to the cylindrical cam 30 is switched to the non-transmission state, and at the same time, an excitation signal is output via the main shaft electromagnetic clutch drive circuit 133 and the main shaft electromagnetic clutch 70 is switched on. The transmission of the rotational force from the motor 50 to the upper shaft 8 is switched to the transmission state (step S31), and the process ends.
On the other hand, if the detection signal from the cam position detection sensor 100 is not OFF in step S27 (step S27; No), that is, if the presser foot 11 is still positioned between the lower position L and the upper position H, the CPU 131 it is judged whether or not the internal timer t ₂ has reached the set value (step S28). When the internal timer t ₂ is less than the set value (step S28; No) detection signal from the cam position sensor 100 and proceeds again to step S27 to perform a is determined whether the OFF. On the other hand, if the internal timer _{t 2} reaches the set value (step S28; Yes), CPU 131 may by lighting an alarm lamp 120 (step S29) notifying the malfunction of the cam position detecting sensor 100 or the cylindrical cam 30 to the operator To do. Thereafter, after stopping (OFF) the sewing machine motor 50 (step S30), the CPU 131 switches the camshaft electromagnetic clutch 80 to OFF and at the same time switches the main shaft electromagnetic clutch 70 to ON (step S29), and ends the processing.

(Effect of embodiment)
As described above, according to the cloth presser foot lifting apparatus 1 of the sewing machine according to the present embodiment, the operator of the sewing machine performs the input operation from the presser foot lifting switch 90 to thereby apply the biasing force by the biasing direction switching mechanism 14. The presser foot 11 can be moved up and down to the lower position L or the upper position H without requiring a large force to resist. Further, by rotating the cylindrical cam 30 using the sewing machine motor 50 having a large rotational force as a drive source, a large thrust for raising and lowering the presser foot 11 to the upper position H or the lower position L can be obtained. Thus, the lifting and lowering operation of the presser foot 11 can be performed smoothly, and a large actuator with a large thrust is not required to move the presser foot 11 up and down, and the space of the device can be reduced.
In addition, when the presser foot 11 is arranged at the lower position L or the upper position H, the operator can manually move the presser foot 11 to the lower position L or the upper position H. The freedom degree of operativity of the raising / lowering apparatus 1 improves. Further, the operator of the sewing machine raises and lowers the presser foot when he / she wants to switch the position where the presser foot 11 is currently arranged, regardless of whether the presser foot 11 has been raised or lowered manually by the manual operation lever 21 or the knee lift lever. By pressing the switch 90, it is possible to switch automatically without manual operation. Further, since the buffer guide portion 33 is provided, it is possible to prevent the presser foot 11 from colliding with the needle plate due to the urging force of the urging direction switching mechanism 14, so that the quality of the sewn product is not damaged without damaging the presser foot or the presser foot 11. Is improved.

(Other)
The cam driving force transmission means can be belt driven by providing the main shaft electromagnetic clutch 70 and the cam shaft electromagnetic clutch 80. In this case, the main shaft 8 and the cam shaft 35 rotate in the same direction, and the rotation direction of the cylindrical cam 30 is opposite to the rotation direction (direction of arrow C) described in the above embodiment. As described above, the positions of the upper position guide portion 31, the lower position guide portion 32, and the buffer guide portion 33 are reversed left or right, or the positions of the follower cam follower 41 and the fulcrum shaft 42a are reversed. The same effect as the embodiment can be obtained.
The cylindrical cam 30 can also be driven by, for example, a pulse motor connected coaxially with the cylindrical cam 30. In this case, the cam position detection sensor 100, the main shaft electromagnetic clutch 70, the cam shaft electromagnetic clutch 80, the presser foot motion detection sensor 110, and the like can be omitted.
Further, since the transmission of the rotational force from the sewing motor 50 to the upper shaft 8 and the cam shaft 35 can be freely switched between the main shaft electromagnetic clutch 70 and the cam shaft electromagnetic clutch 80, for example, the sewing motor 50 In addition to rotationally driving only one of the upper shaft 8 and the cam shaft 35 in a state where the shaft is driven, the upper shaft 8 and the cam shaft 35 may be stopped or driven while the sewing machine motor 50 is driven. It becomes possible.

It is the schematic which shows the principal part structure of the cloth presser foot raising / lowering apparatus of the sewing machine which is this embodiment. It is a schematic explanatory drawing which shows the structure of the presser foot raising / lowering mechanism in this embodiment. It is a side view which shows the external appearance structure of the sewing machine in this embodiment. (A) is a schematic perspective view which shows the structure of the cylindrical cam periphery in this embodiment, (b) is the schematic which shows a cam position detection sensor. It is an expanded view of the cylindrical cam outer periphery in this embodiment. It is a block diagram which shows the structure of the control part in this embodiment. It is a flowchart which shows operation | movement of the cloth presser foot raising / lowering apparatus of the sewing machine which is this embodiment. It is a flowchart which shows operation | movement of the cloth presser foot raising / lowering apparatus of the sewing machine which is this embodiment. It is operation | movement explanatory drawing which shows operation | movement of the cloth presser foot raising / lowering apparatus of the sewing machine which is this embodiment.

Explanation of symbols

1 Presser foot lifting device (cloth presser foot lifting device for sewing machine)
3 sewing machine arm portion 8 upper shaft 9 throat plate 10 presser foot lifting mechanism 11 presser foot 12 presser bar 13 presser bar holder 14 urging direction switching mechanism (biasing direction switching means)
15 Shaft 16 Protrusion 17 Locking member 19 Pressing spring 20 Manual operation mechanism (manual operation means)
21 Manual operation lever 25 Cloth presser foot lifting link 30 Cylindrical cam
31 Upper position guide part 32 Lower position guide part 33 Buffer guide part 34 Manual operation permission part 35 Cam shaft 40 Link mechanism (lifting power transmission means)
41 Cam Follower (follower)
42 First link 42a, 44a Support shaft 43 Second link 44 Third link 50 Sewing motor 51 Motor belt 52 Motor pulley 60 Gear mechanism (cam driving force transmission mechanism)
61 Motor pulley gear 62 Cam gear 70 Main shaft electromagnetic clutch (first electromagnetic clutch)
80 Electromagnetic clutch for camshaft (second electromagnetic clutch)
90 Presser foot lift switch (lifting input means)
100 Cam position detection sensor (cam position detection means)
101 Cam position detection plate 101a Slit (0 °)
101b Slit (180 °)
102 Sensor part 110 Presser foot rise detection sensor (motion detection means)
111 Presser foot rise detection plate 112 Sensor unit 120 Alarm lamp (warning means)
130 Control unit (lift control means)
131 CPU
132 sewing machine motor drive circuit 133 main shaft electromagnetic clutch drive circuit 134 cam shaft electromagnetic clutch drive circuit L cloth presser foot lowering position (lower position)
H Cloth presser foot raised position (up position)
T Cloth presser foot thick cloth rising position (top position)

Claims (7)

The presser foot is supported so as to be able to move up and down between a lower position for pressing the workpiece placed on the needle plate and an upper position for waiting upward when not sewing, and the presser foot is moved from a position on the way to the lower position. A presser foot lifting mechanism comprising a biasing direction switching means for biasing downward and biasing the presser foot upward from a position on the way to the upper position;
A cylindrical cam having an original section having an upper position guide portion for guiding the presser foot to an upper position and a lower position guide portion for guiding the presser foot to a lower position on the outer periphery;
Elevating power transmission means for transmitting power for moving the presser foot to the lower position or the upper position to the presser foot elevating mechanism according to the movement of the follower abutted on the original clause;
Cam driving force transmitting means for transmitting a rotational force from a sewing machine motor serving as a sewing driving source to the cylindrical cam;
A first electromagnetic clutch that receives input of a control signal and switches transmission of rotational force from the sewing machine motor to the upper shaft between a transmission state and a non-transmission state;
A second electromagnetic clutch that receives input of a control signal and switches transmission of rotational force to the cylindrical cam by the cam driving force transmission means between a transmission state and a non-transmission state;
Cam position detecting means for detecting that the cylindrical cam is positioned at a predetermined rotation angle;
Elevating / lowering input means for outputting a lifting / lowering start signal for raising / lowering the presser foot;
The cylindrical cam is driven by driving the sewing machine motor with the first electromagnetic clutch in a non-transmitting state and the second electromagnetic clutch in a transmitting state in response to an input operation from the lifting input means; and A cloth presser foot lifting apparatus for a sewing machine, comprising: a lifting control means for positioning the presser foot at a lower position or an upper position based on a detection signal from a cam position detecting means. Manual operation means for moving the presser foot to a lower position or an upper position by manual operation of an operator;
The said cylindrical cam has a manual operation permission part which accept | permits the movement of the said follower based on the movement to the lower position and upper position of the holding foot by the said manual operation means on the outer periphery. Sewing machine presser foot lifting device. The upper position guide portion is provided in the first half of the cylindrical cam,
The lower position guide is provided in the second half of the cylindrical cam,
The manual operation permission portion is provided between the upper position guide portion and the lower position guide portion,
3. The cloth presser foot lifting / lowering device for a sewing machine according to claim 2, wherein the cam position detecting means detects a rotation angle of the cylindrical cam when the follower is positioned at the manual operation permission portion.   The elevating control means drives the cylindrical cam by driving the sewing motor with the first electromagnetic clutch in a non-transmitting state and the second electromagnetic clutch in a transmitting state when power is turned on, and 4. The cloth presser foot lifting / lowering device for a sewing machine according to claim 2, wherein the follower is disposed in the manual operation permission portion based on a detection signal from a cam position detecting means. Comprising an operation detecting means for detecting the presence or absence of the vertical movement of the presser foot;
The elevating control means is based on the motion detecting means and the cam position detecting means, and when an input operation is performed from the elevating input means when the presser foot is arranged at the lower position, The sewing machine motor is driven until the presser foot is moved to the upper position, and the presser foot is moved to the lower position when an input operation is performed from the lifting input means when the presser foot is disposed at the upper position. The sewing machine cloth presser foot lifting / lowering device according to any one of claims 1 to 4, wherein the sewing machine motor is driven to a maximum. Provide warning means to notify the user of malfunction,
The lifting control means is configured to provide the warning when a detection signal is not detected from either the motion detection means or the cam position detection means after a predetermined period of time has elapsed after power is turned on or after an input operation from the lifting input means. The cloth presser foot lifting / lowering device for a sewing machine according to claim 5, wherein a control process for operating the means is performed.   The said cylindrical cam has the buffer guide part which prevents the collision with the needle plate of the pressing foot by the urging | biasing force of the said urging | biasing direction switching means in the original clause. The sewing machine cloth presser foot lifting device according to one item.

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