JPH0116515B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a presser foot lifting device for a sewing machine.

[Conventional technology]

Conventionally, especially in lock sewing machines, in order to facilitate threading and needle replacement, the presser foot was moved around the presser bar when the presser foot was raised to a predetermined position to release the pressure on the workpiece. A device that can be rotated laterally and retracted out of the sewing machine suture area has been proposed.

In addition, in such a sewing machine, the needle bar is fixed so that even if you accidentally start the sewing machine with the presser foot rotated to the side, you will not be able to stab your finger with the sewing machine needle. The sewing machine is configured so that the sewing machine cannot be started due to contact between the clamp and the presser foot clamp.

[Problem that the invention seeks to solve]

However, in such conventional sewing machines, the presser foot is used to press the workpiece against the top surface of the sewing machine bed using elastic force, and even during normal sewing, thick workpieces or workpieces cannot be easily sewn. When the presser foot is pushed up to its inactive position by the stepped part of the object, the presser bar holder is disengaged from the guide groove, and the presser foot can rotate laterally around the presser bar, which reduces the vibration of the sewing machine and the fabric. The presser foot rotates around the presser bar due to the lateral force component during handling, and as a result, the needle bar holder violently collides with the presser bar holder, potentially damaging them.

[Means for solving problems]

The present invention has been made in view of these conventional problems, and uses a blocking means that functions in conjunction with the operation of the presser foot lifting lever to put the presser foot into an active state, so that the presser foot is inactive during sewing. Even when the presser foot is moved upward to the current position, the presser foot is reliably prevented from moving laterally.

[Embodiments] Examples of the present invention will be described below with reference to FIGS. 1 and 2.

The presser bar 1 is supported on a machine frame so as to be vertically movable and rotatable, and a presser foot 2 is fixed to the lower end of the presser bar 1. The presser bar holder 3 is fixed in the middle of the presser bar 1, and its upper surface receives the lower end of a coiled presser spring 4 compressed between it and the machine frame. As a result, downward presser pressure is always applied to the presser foot 2.

The presser foot lifting lever 5 has two states: when the presser foot 2 presses the workpiece, it is pressed against the bed upper surface 6 through the elastic force of the spring 4, and when it is pressed against the presser spring 4 so as to release the pressure on the workpiece. This is for selectively switching to an inactive state in which the bed is separated upwardly from the bed upper surface 6,
It is rotatably supported by a shaft 8 on a bearing portion 7 of the machine frame.

The presser foot holder 3 is placed on a circular arc with the presser foot 1 at its center and at a predetermined angle (an angle sufficient to retract the presser foot 2 from the normal sewing position to the outside of the sewing machine seam on the side, as will be described later). ) A first engaging part 3a and a second engaging part 3b are formed at two separate positions, and one of the first engaging parts moves the presser foot 2 to the normal sewing position with respect to the cloth feeding direction of the sewing machine. When set up, it is associated with guide means 9 formed in a part of the sewing machine frame.

The guide means 9 includes a pair of guide surfaces 11 and 12 facing each other so as to form a vertical groove in which the first engaging portion 3a of the presser bar holder 3 can move up and down, and a pair of guide surfaces 11 and 12 that extend upward continuously from the guide surface 11. It has an extended guide surface 13 and a locking surface 14 arranged on the back side thereof. Of these, the uppermost portion 12a of the guide surface 12 extends to a position slightly lower than the lower surface of the first engaging portion 3a of the presser bar holder 3 when the presser foot 2 is inactive.

Further, the presser foot lifting lever 5 has a cam portion 1 for switching the presser foot 2 between two states of working and non-working.
A protrusion 16 that protrudes in the radial direction of the shaft 8 is provided at a position different from that of the shaft 5 in the rotation direction. Cam part 1
5 is arranged so as to act on the lower surface of the presser bar holder 3, and the protrusion 16 prevents the presser foot 2 from rotating laterally, no matter where the presser foot 2 is in the operating state. It acts on one side 17 of the presser bar holder 3, and when the presser foot 2 is rotated out of the sewing machine sewing part in the inactive state, the presser foot lifting lever 5 is moved close to the lower surface of the presser bar holder 3. It is arranged to be restrained in position. The protruding portion 16 and the side surface 17 constitute a blocking means, and the protruding portion 16 and the presser bar holder 3 constitute a restraining means.

In FIG. 2, reference numeral 18 denotes a needle bar holder that is interlocked with the needle bar drive mechanism to move the needle bar 19 up and down.

The present invention has the above-described structure, and when the presser foot 2 is in the inactive state shown in FIG. is lifted upward together with the presser bar 19 against the pressing spring 4, and the force pressing the material to be sewn against the bed upper surface 6 is released. In addition, in this state, the presser bar holder 3
The lower surface of the first engaging part 3a is the uppermost part 12 of the guide surface 12.
As shown in FIG. 2b, the first engaging portion 3a is restricted only on one side by the guiding surface 13 of the guiding means 9, and the other side is restricted by the guiding surface 13 of the guiding means 9. There are no restrictions on the sides. Therefore, in the inactive state of the presser foot 2, the presser foot 2 is held until the second engaging portion 3b of the presser bar holder 3 abuts against the locking surface 14 of the guide means 9, as shown in FIG. 2c. can be rotated clockwise in the figure around the presser rod axis. As a result, the presser foot 2 is retracted to a position where it does not interfere with threading or changing the needle.

Note that even if the start switch of the sewing machine is operated by mistake at this time, the needle bar holder 18 will butt against one end of the presser bar holder 3 because the needle bar 19 will be lowered only slightly.
The driving of the sewing machine is mechanically blocked.

Furthermore, when the presser foot 2 is rotated out of the sewing machine suturing section in an inactive state as shown in FIG. From the state, presser foot lifter lever 5
Even when pressed in the clockwise direction in FIG. 2a, the protruding portion 16 comes into contact with the lower surface of the presser bar holder 3 after a slight rotation, and the presser foot lifting lever 5 is restrained in that position.

Next, when the presser foot lifting lever 5 is rotated clockwise in the operating state shown in FIG. 1, the presser foot 2 is lowered from the above-mentioned position, whereby the presser foot 2 presses against the bed upper surface 6. At this time, the first engaging portion 3a of the presser bar holder 3 is located between the guide surfaces 11 and 12 as shown in FIG. regulated. Note that the sewing work is performed while this presser foot 2 is in operation.
As shown in FIG. 1a, at this time, the protrusion 16 of the presser foot lifting lever 5 stands above the uppermost part 12a of the guide surface 12, so if the presser foot 2 runs over a thick step of the material to be sewn, When climbing up, hold the presser bar 3
Even if the lower surface of the first engaging portion 3a is lifted above the top 12a of the guide surface 12, both side surfaces of the presser bar holder 3 are connected to the protrusion 16 and the guide surface 1.
3, the lateral rotation of the presser foot 2 is reliably prevented unless the presser foot lifting lever 5 is operated to the inactive state shown in FIG. 2a.

[Other Examples]

Another embodiment of the invention will be explained based on FIG. Incidentally, the same parts as those in the above embodiment are given the same reference numerals, and the description thereof will be omitted.

The actuating body 20 shown in FIG. 3c has a vertical plate portion 20
a and a horizontal plate part 20b, and a vertical plate part 20a.
One end is rotatably supported by a horizontal shaft 21 on one side of the presser bar holder 3, as shown in FIGS. 3a and 3b. As can be seen from FIG. 3b, the tip of the vertical portion 20a of the operating body 20 is connected to the cam portion 1 of the presser foot lifting lever 5 together with the first engaging portion 3a of the presser bar holder 3.
It is located above 5. And this operating body 20
is pushed upward together with the presser bar holder 3 by the action of the cam surface 15 of the presser foot lifting lever 5 when the presser foot 2 is inactive, so that the lower surface 20c of the vertical portion 20a is lower than the top 12a of the guide surface 12. When the presser foot 2 is in the operating state, the presser foot 2 moves upward, and the guide surface 1 is moved together with the first engaging portion 3a of the presser bar holder 3.
It can be located between 1 and 12.

Therefore, when the presser foot 2 is inactive, the presser foot 2 can be rotated clockwise in FIG. Even if the presser foot 2 is raised to its inactive position as shown in Figure a, at that time the operating body 20 rotates clockwise in the figure around the shaft 21 due to its own weight (of course, it rotates due to elastic force). (An elastic member may be interposed between the presser foot 2 and the presser bar holder 3), whereby a part of the vertical plate portion 20a enters between the guide surfaces 11 and 12, so that the lateral rotation of the presser foot 2 is prevented. movement is prevented.

That is, in the case of this embodiment, the actuating body 20
and the guide surface 12 constitute a blocking means.

〔Effect of the invention〕

As described above, according to the present invention, since the blocking means that operates in conjunction with the operation of the presser foot lifting lever is provided, when the presser foot is inactive, the thread can be threaded by simply pushing the presser foot lightly to one side. The presser foot can be retracted to a position where it does not become an obstacle when threading or replacing the needle, and when the presser foot is in its active state, that is, during sewing, the rotation of the presser foot is ensured even if it is lifted to the position where it is in its inactive state. This has the effect of preventing problems during sewing.

In the embodiment of the present application, the present invention is applied to a presser foot lifting device of a lockstitch sewing machine, but the present invention may also be applied to a presser foot lifting device of a so-called general lockstitch sewing machine.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing an embodiment of this invention.
Figure 1a is a longitudinal sectional view of the main part in the operating state, Figure 1b is a sectional view taken along line A-A in Figure 1a, and Figure 1c is Figure 1a taken along line B-B in Figure 1b. Figure 2a is a vertical cross-sectional view of the main parts in the inactive state, Figure 2b is a cross-sectional view taken along line C-C in Figure 2a, and Figure 2c is the same as Figure 2b. Fig. 3 is a diagram showing another embodiment, Fig. 3a is a vertical sectional view of the main part in the operating state, and Fig. 3b is a diagram showing the main part in the operating state.
FIG. 3c is a perspective view of the actuating body.

Claims (1)

[Scope of Claims] 1. An operating state in which the presser foot is fixed to the lower end of the presser bar, which is always subject to downward elastic force, and the workpiece is pressed against the upper surface of the bed by the elastic force based on the operation of the presser foot lifting lever. and an inactive state in which the presser foot is separated upwardly from the upper surface of the bed against the elastic force so as to release the pressure on the workpiece, and in the active state, the presser foot moves laterally around the presser bar. A presser bar holder fixed to the presser bar so as to be unable to rotate is located between a pair of guide surfaces provided on the machine frame, and when inactive, the presser bar holder slides out upward from between the guide surfaces. In a presser foot lifting device of a sewing machine that enables the presser foot to rotate to the side, the presser foot is operated in conjunction with the operation of the presser foot to the working position by the presser foot lifting lever, and is activated on the side or guide surface of the presser bar holder. The presser foot lifting lever or the presser bar holder is provided with a blocking member that engages with the presser foot and prevents the presser foot from turning to the side even if the presser foot is raised to a non-active position during the working state. A presser foot lifting device for sewing machines.