SEWING MACHINE
A sewing machine includes a main body, a presser bar attached to the main body so as to move along a vertical direction of the sewing machine and detachably holding a presser foot, a needle thread tension adjustment mechanism selectively brought into inactive and active modes, the needle thread tension adjustment mechanism releasing a needle thread tension in the inactive mode and maintaining the needle thread tension in the active mode, and a presser bar lifting lever manually rotated along the vertical direction by a user of the sewing machine and adjusting a position of the presser bar in the vertical direction in accordance with the manual rotation, the presser bar lifting lever including a height adjustment cam portion adjusting the position of the presser bar in the vertical direction and a thread tension adjustment cam portion allowing the needle thread tension adjustment mechanism to adjust the needle thread tension.
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This application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application 2010-122992, filed on May 28, 2010, the entire content of which is incorporated herein by reference.
TECHNICAL FIELDThis disclosure relates to a sewing machine having a presser bar vertically movable and holding a presser foot.
BACKGROUND DISCUSSIONA known presser bar lifting mechanism for a sewing machine disclosed in JP2001-190878A (hereinafter referred to as Reference 1) includes a control unit and a solenoid that moves a presser foot upward, which is consistently biased downward by a presser foot spring. In the aforementioned configuration of the presser bar lifting mechanism, the control unit controls an absorbing force of the solenoid to thereby enable a user of the sewing machine to hold the presser foot in uppermost and intermediate position that is located between the uppermost position and a lowermost position in a vertical direction of the sewing machine.
A known embroidery presser (darning presser) for an embroidery machine is disclosed in JP 2006-263170A (hereinafter referred to as Reference 2). A pivot lever lifting up a presser foot of the embroidery presser is attached to the embroidery presser. The pivot lever moves the presser foot upward in accordance with an upward movement of a presser lifting operation lever. For example, when a user of the embroidery machine moves the embroidery presser upward, the presser foot of the embroidery presser moves further upward than a holder detachably attached to a lower end of a presser bar. Accordingly, a distance between a needle plate and the presser foot in a vertical direction of the embroidery machine increases; therefore, an embroidery frame may be easily detached from an embroidery frame transferring device.
A sewing machine and a presser foot bar lifting device for the same are disclosed in JP2009-112325A (hereinafter referred to as Reference 3). According to the sewing machine and the presser foot bar lifting device for the same of Reference 3, a presser foot lifting lever may rotate from an axial direction of a presser bar toward a right side in a horizontal direction seen from a user of the sewing machine and toward a rear side in a longitudinal direction seen from the user of the sewing machine. Accordingly, when moving the presser foot lifting lever upward and downward, the user of the sewing machine may rotate the presser foot lifting lever toward the right side and the rear side depending on his/her using conditions of the sewing machine. Consequently, when the user of the sewing machine sews a workpiece fabric by means of the sewing machine, the presser foot lifting lever does not interfere with the workpiece fabric. In addition, the operability of the presser bar lifting lever may not deteriorate.
According to the presser bar lifting mechanism described in Reference 1, the solenoid is utilized to the sewing machine in order to move the presser foot and the presser bar upward. Accordingly, for example, when the sewing machine is switched off, the presser foot and the presser bar are not maintained in the respective upward positions and are moved downward by the biasing force of the presser foot spring. In addition, the solenoid and the control unit are utilized in the sewing machine in order to move the presser foot and the presser bar upward, therefore increasing the cost of the sewing machine compared to a domestic manual sewing machine including a manual operated presser bar lifting lever.
According to the presser foot described in Reference 2, in a condition where the presser lifting operation lever is moved upward by the user of the embroidery machine (in a condition where the user of the embroidery machine attaches and detaches the embroidery frame to and from the embroidery frame transferring device), the embroidery frame and the presser foot of the embroidery presser do not make contact with each other in the vertical direction. However, when the presser lifting operation lever is moved downward in a condition where the user of the embroidery machine does embroidery by means of the embroidery machine, the embroidery frame and the presser foot may make contact with each other. In addition, the user of the embroidery machine may do embroidery by not using the presser foot but by using the embroidery frame only. However, according to the embroidery machine of Reference 2, even in a case where the user does embroidery by not using the presser foot but by using the embroidery frame, the embroidery frame and the presser bar may make contact with each other in the vertical direction.
According to Reference 3, in a case where the user of the sewing machine uses an embroidery frame when doing freehand embroidery by means of the sewing machine, the presser foot lifting lever does not make contact with the embroidery frame in a vertical direction of the sewing machine while the presser bar (from which the presser foot is detached) may make contact with the embroidery frame. Further, the presser foot lifting lever does not include a cam adjusting an opening angle between a pair of thread tension disks. In addition, the cam adjusting the opening angle between the pair of thread tension disks rotates about an axis of the presser bar; therefore, it is difficult for such cam to be arranged at the presser foot lifting lever. As a result, the presser foot bar lifting device configured at low cost may not allow the presser bar lifting lever to operate in synchronization with the adjustment of the opening angle between the pair of thread tension disks.
A need thus exists for a sewing machine which is not susceptible to the drawback mentioned above.
SUMMARYAccording to an aspect of this disclosure, a sewing machine includes a main body, a presser bar attached to the main body so as to move along a vertical direction of the sewing machine and detachably holding a presser foot at a lower end, a needle thread tension adjustment mechanism selectively brought into inactive and active modes, the needle thread tension adjustment mechanism releasing a needle thread tension in the inactive mode and maintaining the needle thread tension in the active mode, and a presser bar lifting lever manually rotated about a rotary shaft along the vertical direction by a user of the sewing machine and provided so as to adjust a position of the presser bar in the vertical direction in accordance with the manual rotation, the presser bar lifting lever including a height adjustment cam portion adjusting the position of the presser bar in the vertical direction and a thread tension adjustment cam portion allowing the needle thread tension adjustment mechanism to adjust the needle thread tension, wherein the height adjustment cam portion of the presser bar lifting lever includes a cam profile arranging the presser bar in a lower position in which the sewing machine is operable in a normal sewing mode, the cam profile of the height adjustment cam portion allowing the presser bar to be maintained in a first holding position to which the presser bar is moved further upward from the lower position in the vertical direction, the cam profile of the height adjustment cam portion allowing the presser bar to be maintained in a second holding position to which the presser bar is moved further upward from the first holding position in the vertical direction, and wherein the thread tension adjustment cam portion of the presser bar lifting lever includes a cam profile bringing the needle thread tension adjustment mechanism into the active mode when the presser bar is in the lower position, the cam profile of the thread tension adjustment cam portion bringing the needle thread tension adjustment mechanism into the inactive mode when the presser bar is in the first holding position, the cam profile of the thread tension adjustment cam portion bringing the needle thread tension adjustment mechanism into the active mode when the presser bar is in the second holding position.
The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein:
An embodiment of this disclosure will be explained with reference to illustrations of the accompanying drawings as follows. Vertical, longitudinal, and horizontal directions described herein will correspond to vertical (upper and lower sides), longitudinal (forward and rear sides), and horizontal directions (right and left sides) of a computerized sewing machine (sewing machine) according to the embodiment unless otherwise specified.
As seen from
As illustrated in
As seen from
As seen from
The sewing machine according to the embodiment is applied as a sewing machine by which the user of the sewing machine may do embroidery, freehand embroidery, or the like. Accordingly, as illustrated in
According to the known sewing machine, the user rotates the presser bar lifting lever 30 upward by a rotation angle B1 as the condition (a) of
Further according to the know sewing machine, the user rotates the presser bar lifting lever 30 further upward by a maximum rotation angle C1 shown in
In other words, in the condition (c) of
Next, a mechanism of the presser bar lifting lever 3 according to the embodiment will be explained with reference to
In addition, a cam profile of a cam surface 3b of the thread tension adjustment cam portion 3T of the presser bar lifting lever 3 functions as follows: (a) When the presser bar 5 is in the lower position, the cam profile of the cam surface 3b of the thread tension adjustment cam portion 3T brings the needle thread tension adjustment mechanism 9 into the active mode and allows the first thread tension disk 13b to be closed relative to the second thread tension disk 13c, in order for the sewing machine to be operable in the normal sewing mode; (b) When the presser bar 5 is maintained in the first holding position, the cam profile of the cam surface 3b of the thread tension adjustment cam portion 3T brings the needle thread tension adjustment mechanism 9 into the inactive mode to thereby release the needle thread tension; and (c) When the presser bar 5 is maintained in the second holding position, the cam profile of the cam surface 3b of the thread tension adjustment cam portion 3T brings the needle thread tension adjustment mechanism 9 into the active mode and allows the first tension disk 13b to be closed relative to the second thread tension disk 13c, in order for the sewing machine to be operable in the normal sewing mode.
As the condition (a) of
The sewing machine according to the embodiment differs from the known sewing machine as follows. In a condition where the holder 4 and the presser foot 6 are not attached to the presser bar 5, the user of the sewing machine manually rotates the presser bar lifting lever 3 about the rotary shaft 1c further upward (by a maximum rotation angle C1) as the condition (b) of
Next, a detecting function of the switch for the position of the presser bar lifting lever 3 will be explained as follows with reference to
In the condition (b) illustrated in
Moreover, in the condition (c) illustrated in
As described above, the switch outputs the ON signal 1, the OFF signal, and the ON signal 2 for the lower position, the first holding position, and the second holding position of the presser bar lifting lever 3, respectively. The ON signal 1, the OFF signal, and the ON signal 2 are input to a microcomputer of the main body 1 of the sewing machine and are thereafter processed by the microcomputer. Thus, the sewing machine operates in modes shown in Table 1.
According to the known sewing machine, as shown by the characteristic curved line B2 in
As illustrated in
As illustrated in
For example, the automatic thread tension disk opening/closing mechanism 10 operates so as to separate the first thread tension disk 13b from the second thread tension disk 13c under a condition where the sewing machine is in the embroidery mode or the like. Then, the rod 11 moves in the thread tension releasing direction of the arrow X5 and the shaft 12b of the thread tension releasing operation member 12 is pulled by the wall portion 11y in the thread tension releasing direction of the arrow X5; therefore, the thread tension releasing operation member 12 rotates about the rotary shaft 1a toward the thread tension releasing directions of the arrow X5 and the arrow X6. At this time, the contact portion 12a of the thread tension releasing operation member 12 moves the operating point 13a of the first thread tension disk 13b in the thread tension releasing direction of the arrow X6 and the first thread tension disk 13b separates from the second thread tension disk 13c. As a result, the needle thread tension is released. Thus, the motor 10c of the automatic thread tension disk opening/closing mechanism 10 is driven to pull the rod 11 in the thread tension releasing direction of the arrow X5, thereby automatically releasing the needle thread tension. In such case, even when the free space 11x is arranged in the elongated bore 11a, the thread tension releasing operation member 12 appropriately rotates about the rotary shaft la toward the thread tension releasing directions of the arrows X5 and X6 and the needle thread tension may be automatically released by the automatic thread tension disk opening/closing mechanism 10.
Moreover, the manual operation of the presser bar lifting lever 3 by the user of the sewing machine in a condition where the first thread tension disk 13b is not separated from the second thread tension disk 13c by the automatic thread tension disk opening/closing mechanism 10, i.e. in a condition where the rod 11 is not pulled in the thread tension releasing direction of the arrow X5 by the automatic thread tension disk opening/closing mechanism 10, will be explained as follows. In the aforementioned manual operation of the presser bar lifting lever 3 by the user of the sewing machine, the contact portion 23b of the thread tension releasing arm 23 is moved in the thread tension releasing direction of the arrow X5 by the thread tension adjustment cam portion 3T of the presser bar lifting lever 3 as illustrated in
As described above, according to the sewing machine of the embodiment, when operating the sewing machine in the embroidery mode, the freehand embroidery mode, or the like by means of the embroidery frame, the user of the sewing machine manually rotates the presser bar lifting lever 3 upward to allow the presser bar 5 to be maintained in the second holding position. Accordingly, an upper surface of the embroidery frame does not make contact with the lower end 5d of the presser bar 5 in the vertical direction. In addition, when the presser bar 5 is maintained in the second holding position, the needle thread tension adjustment mechanism 9 is in the active mode and the first thread tension disk 13b is closed relative to the second thread tension disk 13c, therefore allowing the user of the sewing machine to appropriately do freehand embroidery by using the needle thread.
The aforementioned effect according to the embodiment is realized by a mechanical mechanism without addition of an actuator and may be obtained at low cost. According to the known sewing machine, for example, in a case where the presser bar lifting lever 30 is not moved downward by the user of the sewing machine before doing freehand embroidery, the needle thread tension adjustment mechanism 9 does not shift to the active mode and the needle thread tension remains loosened. Moreover, according to the known sewing machine, the lower end 5d of the presser bar 5 is positioned in such a manner to contact the upper surface of the embroidery frame in the vertical direction. Accordingly, when doing embroidery, freehand embroidery, or the like, the user of the sewing machine needs to be careful so that the upper surface of the embroidery frame does not make contact with the lower end 5d of the presser bar 5 in the vertical direction.
According to the configuration of the sewing machine of the embodiment as described above, the switch may detect three rotational positions of the presser bar lifting lever 3 such as the lower position, the first holding position, and the second holding position. In a condition where the presser bar lifting lever 3 is moved down by the user of the sewing machine to the lower position, the sewing machine is operable in the normal sewing mode and may select the sewing pattern related only to the normal sewing mode. Further, in a condition where the presser bar lifting lever 3 is moved by the user of the sewing machine to the second holding position and is maintained thereat, the swing machine is operable in the embroidery mode and the user may select the sewing pattern related only to the embroidery mode, the freehand embroidery mode, or the like. Accordingly, usability and safety of the user of the sewing machine may increase. Furthermore, in a condition where the presser bar lifting lever 3 is moved by the user of the sewing machine to the first holding position and is maintained thereat, the sewing machine is not operable in the same way as the known sewing machine; thereby, the safety of the user of the sewing machine may be maintained. Such effect may be realized by the simply configured switch and the mechanical mechanism; therefore, the inexpensive sewing machine may be obtained. In addition, according to the known sewing machine, a switch is applied to thereby detect two rotational positions of the presser bar lifting lever 30.
Moreover, according to the aforementioned configuration of the sewing machine of the embodiment, for example, even when the user of the sewing machine accidentally tries to do embroidery, freehand embroidery, or the like under a condition where the presser foot 6 is attached to the lower end 5d of the presser bar 5, the presser bar lifting lever 3 may not be moved upward to the second holding position and may not be maintained thereat; therefore, the user of the sewing machine may not shift the sewing machine from the normal sewing mode to the embroidery mode. Thus, the user of the sewing machine may not operate the sewing machine in the embroidery mode, the freehand embroidery mode, or the like in a condition where the presser foot 6 is accidentally attached to the lower end 5d of the presser bar 5 by the user of the sewing machine.
The configuration of the sewing machine according to the disclosure is not limited to the embodiment described above and illustrated in the attached drawings, and may be modified according to need as long as not deviating from the purpose of the disclosure.
As described above, according to the aforementioned embodiment, the sewing machine includes the main body 1, the presser bar 5 attached to the main body 1 so as to move along the vertical direction of the sewing machine and detachably holding the presser foot 6 at the lower end 5d, the needle thread tension adjustment mechanism 9 selectively brought into the inactive and active modes, the needle thread tension adjustment mechanism 9 releasing the needle thread tension in the inactive mode and maintaining the needle thread tension in the active mode, and the presser bar lifting lever 3 manually rotated about the rotary shaft 1c along the vertical direction by the user of the sewing machine and provided so as to adjust the position of the presser bar 5 in the vertical direction in accordance with the manual rotation, the presser bar lifting lever 3 including the height adjustment cam portion 3H adjusting the position of the presser bar 5 in the vertical direction and the thread tension adjustment cam portion 3T allowing the needle thread tension adjustment mechanism 9 to adjust the needle thread tension. The height adjustment cam portion 3H of the presser bar lifting lever 3 includes the cam profile arranging the presser bar 5 in the lower position in which the sewing machine is operable in the normal sewing mode. The cam profile of the height adjustment cam portion 3H allows the presser bar 5 to be maintained in the first holding position to which the presser bar 5 is moved further upward from the lower position in the vertical direction. The cam profile of the height adjustment cam portion 3H allows the presser bar 5 to be maintained in the second holding position to which the presser bar 5 is moved further upward from the first holding position in the vertical direction. The thread tension adjustment cam portion 3T of the presser bar lifting lever 3 includes the cam profile bringing the needle thread tension adjustment mechanism 9 into the active mode when the presser bar 5 is in the lower position. The cam profile of the thread tension adjustment cam portion 3T brings the needle thread tension adjustment mechanism 9 into the inactive mode when the presser bar 5 is in the first holding position. The cam profile of the thread tension adjustment cam portion 3T brings the needle thread tension adjustment mechanism 9 into the active mode when the presser bar 5 is in the second holding position.
According to the aforementioned embodiment, the presser bar 5 includes the presser bar holding member 20 supported by the presser bar 5. The cam profile of the height adjustment cam portion 3H of the presser bar lifting lever 3 includes the first cam surface 3c being in contact with the presser bar holding member 20 at the upper side of the rotary shaft 1c and positioned on the straight line P when the presser bar 5 is in the first holding position, the straight line P passing through the central axis of the rotary shaft 1c so as to be perpendicular to the central axis, and the second cam surface 3d being in contact with the presser bar holding member 20 at the upper side of the rotary shaft 1c and positioned on the straight line P when the presser bar 5 is in the second holding position.
Accordingly, even when the user of the sewing machine does embroidery, freehand embroidery, or the like under a condition where the presser bar lifting lever 3 is maintained in the second holding position, the embroidery frame is prevented from making contact with the presser bar 5; therefore, the user of the sewing machine may appropriately operate the sewing machine in the embroidery or freehand embroidery mode.
In other words, when the user of the sewing machine does embroidery, freehand embroidery, or the like by using the embroidery frame, the presser bar 5 may be maintained in the second holding position so as not to move downward in order to prevent the embroidery frame from making contact with the lower end 5d of the presser bar 5. In addition, when the presser bar 5 is maintained in the second holding position, the needle thread tension adjustment mechanism 9 maintains the needle thread tension; therefore, the needle thread tension for the embroidery or freehand embroidery may be realized by an inexpensive mechanism. In particular, when the user of the sewing machine does embroidery, freehand embroidery, or the like by using the embroidery frame, the presser bar 5 is maintained at the upper side of the upper surface of the embroidery frame and the needle thread tension adjustment mechanism 9 adjusts the needle thread tension suitably for the embroidery or freehand embroidery. As a result, the user of the sewing machine may appropriately or desirably do embroidery, freehand embroidery, or the like while not being affected by the contact between the embroidery frame and the presser bar 5.
According to the aforementioned embodiment, the first cam surface 3c of the cam profile of the height adjustment cam portion 3H extends along the horizontal direction of the sewing machine when the presser bar 5 is in the first holding position. The second cam surface 3d of the cam profile of the height adjustment cam portion 3H extends along the horizontal direction of the sewing machine.
Accordingly, the first cam surface 3c and the second cam surface 3d of the presser bar lifting lever 3 may form the cam profiles for holding the presser bar 5 and the presser bar holding member 20 and preventing the presser bar 5 and the presser bar holding member from moving downward. In such case, the presser bar 5 is moved to the first holding position and is maintained thereat. As a result, under a condition where the presser bar 5 is maintained in the first holding position, the needle thread tension adjustment mechanism 9 is brought into the inactive mode and the first thread tension disk 13b is separated from the second thread tension disk 13c; therefore, the needle thread tension is loosened. Meanwhile, in a condition where the presser bar 5 is maintained in the second holding position, the needle thread tension adjustment mechanism 9 is brought into the active mode and the first thread tension disk 13b is closed relative to the second thread tension disk 13c; therefore, the needle thread tension is maintained. According to the aforementioned embodiment, the sewing machine further includes the switch detecting the lower position, the first holding position, and the second holding position of the presser bar 5.
According to the aforementioned embodiment, the sewing machine further includes the switch lever 15 rotating along with the rotation of the presser bar lifting lever 3. The switch outputs the ON signal 1 when detecting that the switch lever 15 is rotated in the first direction R2. The switch outputs the OFF signal when detecting that the switch lever 15 is rotated to the intermediate position. The switch outputs the ON signal 2 when detecting that the switch lever 15 is rotated in the second direction R1. The sewing machine is operable in the normal sewing mode when the lower position of the switch lever 15 is determined on the basis of the ON signal 1 outputted from the switch. The sewing machine is not operable in the normal sewing mode when the first holding position of the switch lever 15 is determined on the basis of the OFF signal outputted from the switch. The sewing machine is operable in the normal sewing mode when the second holding position of the switch lever 15 is determined on the basis of the ON signal 2 outputted from the switch.
Thus, information required for automatically changing a sewing pattern program along with the manual operation of the presser bar lifting lever 3 by the user and information required for safely activating the sewing machine may be provided by the inexpensive and simply configured switch detecting the lower position, the first holding position, and the second holding position of the presser bar 5.
According to the aforementioned embodiment, the sewing machine further includes the stopper 7 attached to the main body 1. The stopper 7 makes contact with either one of the presser foot 6 and the holder 4 for attaching the presser foot 6 to the presser bar 5, and restricts the presser bar 5 from shifting to the second holding position in a state where the presser foot 6 is attached to the presser bar 5.
Thus, the stopper 7 prevents the user of the sewing machine from operating the sewing machine in the embroidery mode, the freehand embroidery mode, or the like in a condition where the presser foot 6 is accidentally attached to the lower end 5d of the presser bar 5 by the user. In addition, the stopper 7 prevents the presser foot 6 (or the holder 4) from making contact with the needle clamp 8 under a condition where the presser bar lifting lever 3 is maintained in the second holding position; therefore, the damage of the embroidery frame and the presser foot 6 due to the contact therebetween is prevented. As a result, the safety for the user of the sewing machine may increase.
According to the aforementioned embodiment, the sewing machine further includes the thread tension releasing operation member 12 selectively bringing the needle thread tension adjustment mechanism 9 into the inactive and active modes, the rod 11 engaged with the thread tension releasing operation member 12, the motor 10c electrically operating the thread tension releasing operation member 12 and the rod 11 to bring the needle thread tension adjustment mechanism 9 into the inactive mode, and the thread tension releasing arm 23 operating the thread tension releasing operation member 12 in accordance with the manual rotation of the presser bar lifting lever 3 by the user of the sewing machine to bring the needle thread tension adjustment mechanism 9 into the inactive mode. The thread tension releasing operation member 12 includes the shaft 12b and the rod 11 includes the elongated bore 11a having the free space 11x to which the shaft 12b of the thread tension releasing operation member 12 is fitted. The elongated bore 11a is larger in size than the shaft 12b. When the motor 10c is driven in the direction to move the rod 11 in the thread tension releasing direction of the arrow X5, the thread tension releasing operation member 12 is moved via the shaft 12b by the rod 11 to bring the needle thread tension adjustment mechanism 9 into the inactive mode.
In particular, when the motor 10c is rotatably driven in one direction to move the rod 11 in the thread tension releasing direction of the arrow X5, the thread tension releasing operation member 12 is moved via the shaft 12b by the rod 11 to bring the needle thread tension adjustment mechanism 9 into the inactive mode. Further, when the motor 10c is rotatably driven in the other direction to move the rod 11 in the opposite direction from the thread tension releasing direction of the arrow X5, the elongated bore 11a of the rod 11 is moved relative to the shaft 12b via the free space 11x in the opposite direction to prevent the movement of the rod 11 from being transmitted to the thread tension releasing operation member 12.
According to the aforementioned embodiment, when the presser bar lifting lever 3 is manually rotated by the user of the sewing machine and the thread tension releasing operation member 12 is moved by the thread tension adjustment cam portion 3T in the thread tension releasing direction of the arrow X5 to bring the needle thread tension adjustment mechanism 9 into the inactive mode, the shaft 12b moves in the elongated bore 11a therealong and the free space 11x of the elongated bore 11a prevents the movement of the thread tension releasing operation member 12 from being transmitted to the rod 11.
The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.
Claims
1. A sewing machine, comprising:
- a main body;
- a presser bar attached to the main body so as to move along a vertical direction of the sewing machine and detachably holding a presser foot at a lower end;
- a needle thread tension adjustment mechanism selectively brought into inactive and active modes, the needle thread tension adjustment mechanism releasing a needle thread tension in the inactive mode and maintaining the needle thread tension in the active mode; and
- a presser bar lifting lever mounted to the main body for rotation about a rotary shaft along the vertical direction of the main body, the presser bar lifting lever including a height adjustment cam portion adjusting the position of the presser bar in the vertical direction and a thread tension adjustment cam portion allowing the needle thread tension adjustment mechanism to adjust the needle thread tension,
- wherein the height adjustment cam portion of the presser bar lifting lever includes a cam profile arranging the presser bar in a lower position in which the sewing machine is operable in a normal sewing mode, the cam profile of the height adjustment cam portion allowing the presser bar to be maintained in a first higher holding position to which the presser bar is moved further upward from the lower position in the vertical direction, the cam profile of the height adjustment cam portion allowing the presser bar to be maintained in a second higher holding position to which the presser bar is moved further upward from the first holding position in the vertical direction, and
- wherein the thread tension adjustment cam portion of the presser bar lifting lever includes a cam profile bringing the needle thread tension adjustment mechanism into the active mode when the presser bar is in the lower position, the cam profile of the thread tension adjustment cam portion bringing the needle thread tension adjustment mechanism into the inactive mode when the presser bar is in the first higher holding position, the cam profile of the thread tension adjustment cam portion bringing the needle thread tension adjustment mechanism into the active mode when the presser bar is in the second higher holding position.
2. The sewing machine according to claim 1, wherein the presser bar includes a presser bar holding member supported by the presser bar, and
- wherein the cam profile of the height adjustment cam portion of the presser bar lifting lever comprises:
- a first cam surface being in contact with the presser bar holding member at an upper side of the rotary shaft and positioned on a straight line when the presser bar is in the first holding position, the straight line passing through a central axis of the rotary shaft so as to be perpendicular to the central axis; and
- a second cam surface being in contact with the presser bar holding member at the upper side of the rotary shaft and positioned on the straight line when the presser bar is in the second holding position.
3. The sewing machine according to claim 2, wherein the first cam surface of the cam profile of the height adjustment cam portion extends along a horizontal direction of the sewing machine when the presser bar is in the first holding position, and the second cam surface of the cam profile of the height adjustment cam portion extends along the horizontal direction of the sewing machine.
4. The sewing machine according to claim 1, further comprising a switch detecting the lower position, the first holding position, and the second holding position of the presser bar.
5. The sewing machine according to claim 4, further comprising a switch lever rotating along with the rotation of the presser bar lifting lever, wherein the switch outputs a first ON signal when detecting that the switch lever is rotated in a first direction, the switch outputting an OFF signal when detecting that the switch lever is rotated to an intermediate position, the switch outputting a second ON signal when detecting that the switch lever is rotated in a second direction, and
- wherein the sewing machine is operable in the normal sewing mode when the lower position of the switch lever is determined on the basis of the first ON signal outputted from the switch, the sewing machine is not operable in the normal sewing mode when the first holding position of the switch lever is determined on the basis of the OFF signal outputted from the switch, and the sewing machine is operable in the normal sewing mode when the second holding position of the switch lever is determined on the basis of the second ON signal outputted from the switch.
6. The sewing machine according to claim 1, further comprising an embroidery restriction member attached to the main body, the embroidery restriction member making contact with either one of the presser foot and a holder for attaching the presser foot to the presser bar, and restricting the presser bar from shifting to the second holding position in a state where the presser foot is attached to the presser bar.
7. The sewing machine according to claim 1, further comprising:
- a thread tension releasing operation member selectively bringing the needle thread tension adjustment mechanism into the inactive and active modes;
- a rod engaged with the thread tension releasing operation member;
- a motor electrically operating the thread tension releasing operation member and the rod to bring the needle thread tension adjustment mechanism into the inactive mode; and
- a thread tension releasing portion operating the thread tension releasing operation member in accordance with the manual rotation of the presser bar lifting lever by the user of the sewing machine to bring the needle thread tension adjustment mechanism into the inactive mode,
- wherein the thread tension releasing operation member includes a protruding portion and the rod includes an elongated bore having a free space to which the protruding portion of the thread tension releasing operation member is fitted, the elongated bore being larger in size than the protruding portion, and
- wherein when the motor is driven in a direction to move the rod in a thread tension releasing direction, the thread tension releasing operation member is moved via the protruding portion by the rod to bring the needle thread tension adjustment mechanism into the inactive mode.
8. The sewing machine according to claim 7, wherein when the presser bar lifting lever is manually rotated by the user of the sewing machine and the thread tension releasing operation member is moved by the thread tension adjustment cam portion in the thread tension releasing direction to bring the needle thread tension adjustment mechanism into the inactive mode, the protruding portion moves in the elongated bore therealong and the free space of the elongated bore prevents the movement of the thread tension releasing operation member from being transmitted to the rod.
9. A sewing machine, comprising:
- a main body;
- a presser bar attached to the main body for movement along a vertical direction of the main body and having a lower end to which a presser foot is detachably connected;
- a needle thread tension adjustment mechanism configured to, when being in its inactive and active modes, releasing and maintaining a needle thread tension, respectively; and
- a presser bar lifting lever pivoted to the main body via a rotary shaft for manual rotational movement along the vertical direction of the main body,
- the presser bar lifting lever including a height adjustment cam portion for adjusting a height of the presser bar upon the manual rotational movement of the presser bar lifting lever and a thread tension adjustment cam portion for adjusting the needle thread tension,
- wherein the height adjustment cam portion of the presser bar lifting lever has a cam profile which allows the presser bar to locate at selective one of a lower position for a normal sewing mode, a first higher holding position having a higher elevation than the lower position, and a second higher holding position having a higher elevation than the first higher holding position, and
- wherein the thread tension adjustment cam portion has a cam profile which causes the needle thread tension adjustment mechanism to operate in the active mode, the inactive mode, and the active mode, when the presser bar locates at the low position, the first holding position, and the second holding position, respectively.
Type: Application
Filed: May 12, 2011
Publication Date: Dec 1, 2011
Applicant: AISIN SEIKI KABUSHIKI KAISHA (Kariya-shi)
Inventor: Yasunori KAWAI (Nagoya-shi)
Application Number: 13/106,425
International Classification: D05B 29/02 (20060101);