JPS5931190Y2 - Sewing machine flywheel mounting mechanism - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a handwheel mounting mechanism for a sewing machine, which allows for easy assembly of the handwheel even if the space at the rear end of the sewing machine is reduced to mount a needle sewing device. The flywheel is securely restrained in the axial and rotational directions, does not require screw tightening, eliminates damage caused by screw tightening, and allows the user to easily attach and detach the flywheel.

A recently proposed sewing machine that can perform one-hitter operation has -
Since the mechanism for the eaves gutter is attached to the rear end of the sewing machine, there is not enough space for attaching the flywheel.

For this reason, with conventional products, the attachment mechanism of the flywheel is also difficult, sometimes making it difficult to assemble during assembly, or products made of synthetic resin may be damaged when tightened with screws, and furthermore, the attachment and detachment operations by the user may be difficult. It has drawbacks such as not being easy.

The present invention has been made to eliminate the drawbacks of the conventional products as described above, and embodiments of the present invention will be described below with reference to the drawings in connection with a single stitch sewing device.

First, to explain the needle sewing device, 1 is the main body of the sewing machine, 2 is a belt driven by a sewing machine motor (not shown), 3 is an intermediate pulley that is pivotally supported by the sewing machine main body 1 and rotated by the belt; A belt 4 is driven by the intermediate pulley and rotates the belt pulley 5.

The belt pulley 5 is loosely fitted into a bushing 8 that is connected to the upper shaft 6 of the sewing machine with a screw 7, and can be rotated idly.
Further, the rotation of the belt pulley 5 is integrally transmitted via the belt clutch device 9.

Further, as shown in FIG. 7, five pins 10 are integrally formed on the front side of the sewing machine of the belt pulley 5, and a pawl 11 is swingably fitted into each of these pins.

When the belt pulley 5 rotates, the pawls 11 are displaced outward and spread out due to centrifugal force, and this displacement hits the side wall 13 of the counterbore surface 12 of the belt pulley 5, limiting the outward spread. It has become so.

The declutching device 9 has a roller 18 interposed in a space formed by a flat plate 15 disposed in a groove 14 of a bushing 8 and an inner circumferential surface 17 of a hole 16 of a belt pulley 5. It is configured by holding it in a square hole 21 of.

Then, as the arm 20 rotates counterclockwise relative to the bushing 8, the roller 18 is pushed into a narrower space, so the belt pulley 5 and the bushing 8 are integrated, and conversely, the bushing 8 is rotated counterclockwise. When the arm 20 rotates relatively clockwise, the roller 18 is pushed out into a wider space, so the belt pulley 5 becomes idle relative to the bush 8.

The stopper cam 19 has a shape as shown in FIG. 6, and a cam 24 having a notch 23 is formed on the circumference of the large diameter portion 22, and the aforementioned clutch device 9 is formed in the middle diameter portion 25.
An arm 20 for holding the roller 18 is formed, and an arcuate recess 27 for accommodating the spring 26 is formed.

Further, reference numerals 28 and 29 denote arc-shaped elongated holes, two of which are provided approximately symmetrically with respect to the center of rotation, and which pass through the main body of the stopper cam 19.

In addition, a counter-sunk surface 30 is formed at the counterclockwise end of each of these elongated holes 28 and 29, and the counter-sunk surface 30 and the other clockwise elongated holes are narrow parts. A buffer member 31, 32 made of polyurethane rubber or the like is inserted into the counterbore surface 30, and a head portion 33 formed at one end of the buffer member 31, 32 is fitted into the counterbore surface 30. The rotation is stopped and the axial position is determined at the same time.

The narrow portions described above also prevent the buffer members 31, 32 from moving clockwise.

Further, stepped screws 34.35 are inserted into the elongated holes 28.29, and the stepped screws 34.35 are tightened and fixed to the side surface of the bush 8.

Furthermore, the small diameter portion 36 is located at the hole center 3 of the ratchet wheel 37 and washer 38.
9.40.

Further, on the front side of the sewing machine, there is provided one end 4 of a spring 41 that always presses the stopper cam 19 counterclockwise with respect to the upper shaft 6.
2 is fitted, and the other end 43 of the spring is fitted into the side surface of a sprocket 44 fixed to the upper shaft 6.

A timing belt 45 is wound around the sprocket to drive the lower shaft and the like.

46 is a release cam, which has a shape as shown in FIG.

That is, the flange portion 47 has the largest diameter, and a protrusion 49 for releasing the stopper 48 is formed on the front side of the sewing machine, and a cylindrical portion 51 with four recesses 50 formed on the outer periphery is formed on the rear side. The claws 11 are provided in these recesses 50.
The protrusion 52 is designed to be depressed.

The inner diameter of the hole 53 is the same as that of the inner diameter portion 25 of the stopper cam 19.
The release cam 46 and the stopper cam 19 are fitted at this portion.

A protrusion 55 is formed on the inner circumferential surface 54 of the hole 53, and the protrusion enters the arc-shaped recess 27 of the stopper cam 19, and the recess 2
A spring 26 is housed between the clockwise end of the bush 8 and the protrusion 55, and as a result, the release cam 46 is always pressed counterclockwise from the bush 8 (see FIGS. 16, 17, etc.). ).

The axial movement of the release cam 46 is achieved by moving the ratchet wheel 37 with the screw 5.
6 is restricted by being fixed to the side surface of the stopper cam 19, and movement relative to the stopper cam 19 is free within a certain range only in the rotational direction.

Four cam surfaces 57 are formed on the outer periphery of the ratchet wheel 37, and since the protrusion 52 of the pawl 11 is wide, it engages both these cam surfaces 57 and the outer peripheral surface of the cylindrical portion 51 of the release cam 46. match.

When the protrusion 52 of the pawl 11 falls into the recess 50 of the release cam 46 and the release cam 46 rotates in advance relative to the ratchet wheel 37, the protrusion 52 of the pawl 11 rises along the cam surface 57, causing the pawl 11 to move upward. It has the role of releasing the release cam 46 from the recess 50.

58.59 are long holes corresponding to the long holes 28 and 29 of the stopper cam 19, and the cylindrical portion 60.6 of the stepped screw 34.35
1 passes through the elongated hole.

62 is a long hole through which the arm 20 of the stopper cam 19 passes.

The washer 38 is fastened to the bushing 8 by step screws 34, 35, and not only determines the axial position of the belt pulley 5, but also serves as a guide when the belt pulley 5 idles relative to the bushing 8.

63 is a belt wheel holder, with projections 65 on the inside from both ends.
The presser arm 64 is formed by being bent, and the presser arm 64 has a spring action.

Then, the bushing 8 is connected to the cylindrical head screw 66 and the screw 67.
is fixed to the side of the

Note that 68 is a spring washer that is loosely fitted into the bushing 8 and is interposed between the belt wheel presser foot 63 and the belt wheel 5 to lightly press the belt wheel 5 toward the front side of the sewing machine.
(see figure).

As shown in FIG. 5, the flywheel 69 has a retaining portion 71 formed in its boss portion 70, in which the intermediate portion expands to increase the outer diameter and the inner portion recesses to decrease the outer diameter. The protrusion 65 of the presser arm 64 of the belt wheel presser 63 presses the flywheel 8 toward the center of the upper shaft 6, so the flywheel 8 is pressed by the bell and the wheel presser 63, and under normal conditions it will not come out from the upper shaft 6. A part of the boss portion 70 has a hole 72 as shown in FIG.
is provided, and a cylindrical head 73 of the headed screw 66 fixed to the bushing 8 engages in the hole.

Therefore, the flywheel 69 is also restrained in the rotational direction relative to the upper shaft 6, and the phase relative to the upper shaft 6 is determined.

If the flywheel 69 is pulled toward the rear side, the boss portion 70 will push out the presser arm 64 of the belt wheel presser 63, allowing the flywheel 69 to be removed from the upper shaft 6.

The mechanisms attached to the upper shaft 6 are as described above, and the mechanisms that control them will now be described.

48 is a stopper, and the shaft 7 is fixed to the sewing machine body 1.
It is pivoted to 4 and can swing.

The tip 75 of the stop flange 48 is adapted to engage with both the outer peripheral surface of the large diameter portion 22 of the stopper cam 19 and the projection 49 of the release cam 46, and the rear end 76 is adapted to engage with a support plate 77 fixed to the sewing machine main body 1. It is pulled by a spring 78 and always urged to rotate clockwise.

A projection 79 is formed downward between the center portion 80 and the rear end 76 and engages with a single stitch selection cam 81 pivotally connected to a shaft 80 fixed to the sewing machine body 1.

The single stitch selection cam 81 has a shape as shown in FIG. 6, and includes a circular arc portion 83 equidistant from the rotation center 82, recesses 84 and 85 provided on the circular arc, a cam surface 86, and an arm. 87.

The radius of curvature of the recesses 84 and 85 is matched with that of the protrusion 79 of the stopper 48, and when the protrusion engages with the recess 84 or 85, the stopper 48 is kept at a constant position rotated counterclockwise. , the sewing machine will be in normal sewing mode.

By providing the recesses 84 and 85, moderation can be provided in the recesses for switching between high-speed and low-speed sewing in normal sewing, and there is no need to consider this moderation at the contact 89 of the selection switch 88. Therefore, a complete electrical connection can also be made.

A rod 90 is connected to the arm 87, and the lower end of the iron rod is connected to an operating knob 91 of a selection switch 88.

A recess 92 is formed on the back surface of the operating knob 91, and a connecting piece 93 is accommodated in the recess.

The contact surface 94 of the connecting piece 93 with respect to the contact 89 is formed in a planar shape so that a complete electrical connection can be obtained with the contact 89.

Four contacts 89 are provided, and the connecting pieces 93 connect contacts a and b.
By contacting with , high-speed stitching of normal stitching is selected; by contacting contact point C, low-speed stitching of normal stitching is also selected; and by contacting contact points C and d, high-speed stitching of normal stitching is selected. The electrical circuit is configured so that the eave gutter is selected.

Next, the configuration of the thread winding device will be explained.

A declutch arm 95 has a shape as shown in FIG. 6, and is pivotally connected to the shaft 74 together with the stopper 48.

The tip 96 is rotated clockwise by the rotation of the pincushion arm 97, so that the stopper cam 19
It is configured to engage only.

Further, a spring 99 is hooked to the hole 98 and biased to rotate clockwise.

One end 101 of the peg arm 97 is in contact with the upper end 100, and normally presses the declutch arm 95 counterclockwise against the spring 99.

As shown in FIG. 4, the bobbin winding arm 97 is pivotally connected to the sewing machine body 1, and the other end 103 is pressed against the pin 104 by a spring 102 to be in a released state.

When winding the bobbin, it rotates counterclockwise by manual operation.
A rubber ring 105 is pressed against a knurled surface 106 of the belt pulley 5 by the action of a spring 102, and at the same time one end 101 is adapted to release the clutch arm 95.

The present invention is constructed as described above, and its operation will be explained next.

First, to explain the case of normal sewing, when the operation knob 91 of the selection switch 88 is moved to the uppermost position,
Contacts a and b are connected by the connecting piece 93 to form an electric circuit in which the power supply voltage is directly applied to the sewing machine motor, and the sewing machine motor is rotated between 0 and the power supply voltage according to the amount of depression of the controller. I can do it.

That is, by moving the operating knob 91 upward, the rod 90 rotates the single stitch selection cam 81 clockwise, the cam surface 86 presses the protrusion 79 of the stopper 48, and the protrusion is set in the recess 85. As a result, the stopper 48 rotates counterclockwise and its tip 75 moves out of the movement path of the cam 24 of the stopper cam 19 and the protrusion 49 of the release cam 46 and never engages with them. The belt pulley 5 and bushing 8 are integrally connected via rollers 18, and the rotation of the belt pulley 5 is directly transmitted to the upper shaft 6, allowing the sewing machine to rotate continuously and perform normal sewing.

This also applies when the operating knob 91 is set to an intermediate position.

However, when set to the intermediate position, when the connecting piece 94 makes contact, it connects C and a low-speed electric circuit is formed, so that the sewing machine performs continuous low-speed sewing.

Further, during these continuous stitches, the needle of the sewing machine stops at a completely unspecified position, and after stopping, it can be moved to any position by surrounding the flywheel 69 with the hand.

Next, we will explain the case where one house gutter is used.

By setting the operation knob 91 to the lowest position, the first
As shown in the figure, the selection cam 81 rotates counterclockwise, the stopper 48 rotates clockwise due to the spring 78, and the tip 7
5 enters the movement path of the cam 24 of the stopper cam 19 and the projection 49 of the release cam 46.

Then, when the controller is depressed, the sewing machine rotates at a low speed, and as shown in FIGS. 8 and 9, the recess 5 of the release cam 46
0 and the concave portion 57' of the cam 57 of the rook 37 do not coincide with each other, and their convex portions fill in the concave portions.

The projection 49 of the release cam 46 is connected to the tip 7 of the stopper 48.
gradually approaching 5.

At this time, the stopper cam 19 is given rotational force from the sprocket 44 via the spring 41, and the release cam 46
are rotated together by a rotational force applied from the clockwise end of the arc-shaped recess 27 of the stopper cam 19 via the spring 26.

Therefore, as shown in FIG. 10, when the protrusion 49 of the release cam 46 reaches the tip 75 of the stopper 48, the release cam 46 stops.

However, since the counterclockwise rotational force of the stopper cam 19 due to the spring 41 exceeds the clockwise rotational force due to the spring 26, the stopper cam 19 continues to rotate while the spring 26 is compressed, and as a result, the notch 23 rotates against the stopper 48. Tip 75
It is only then that the rotation of the stopper 48 stops.

When the spring 26 is compressed as shown in FIG. 10, the recess 50 of the release cam 46 and the recess 57' of the cam 57 of the rook 37
are in the same phase, and the protrusion 52 of the claw 11 can be lowered.

However, in this case, belt wheel 5 and bushing 8 are connected to roller 1.
Since the bushing 8 is integrated with the roller 8, it will continue to rotate, so the bushing 8 will rotate while leaving the roller 18. As a result, the roller 18 will move into a wider space (clockwise) and the belt wheel will rotate. 5 and the bushing 8 are disconnected, and the belt pulley 5 becomes idle.

On the other hand, the low rotation part of the upper shaft 6 integrated with the pusher 8 was rotating with considerable inertia, so the cylindrical part 60, 61 of the stepped bolt 34, 35 fixed to the bush 8 was inserted into the elongated hole 28.
, 29, and collides with the buffer members 31, 32, and the sewing machine completely stops for the first time.

At this time, since the declutch device 9 is already in the released state, the rotational force when the cylindrical portion 60.61 of the stepped ratchet 34.35 collides with the buffer member 31.32 is only the inertial force, so there is no difference. The impact is not that big, but this impact member 3
1.32 absorbs the shock, so the shock and noise when the sewing machine stops is extremely small.

Note that at this time, the needle of the sewing machine will stop at a predetermined position near the top dead center.

In this case, as long as the controller is continuously depressed, the belt pulley 5 continues to idle, so the pawl 11 retreats outward due to its own centrifugal force, and the pawl 11 is inserted into the recess 50 of the release cam 46.
The protrusions never engage.

When the controller is released, the belt pulley 5 stops, and the centrifugal force acting on the pawl 11 disappears, so that the pawl 11 above the upper shaft 6 is aligned in phase, as shown in Figure 10. It is now ready to fall into the recesses 50 and 57'.

Note that since the belt pulley 5 stops at an unspecified position, the pawl 11 does not necessarily fall into the recess 50, 57' at the same time as the belt pulley 5 stops, as shown in FIG. If it rotates, it will fall immediately, so there is no problem.

Next, when the controller is depressed again, the belt pulley 5 starts rotating, and the pawl 11 is moved between the release cam 46 and the concave portion 5 of the rook 37.
0.57', and as shown in FIG.
1 rotates the release cam 46.

As a result, the spring 26 is restored again, and the pawl 11 is moved to the rook 3.
The release cam 46 raises itself along the cam surface 57 of the
, the engagement with the rook 37 is disengaged, and the protrusion 49 of the release cam 46 rotates the stopper 48 counterclockwise against the force of the spring 78, thereby releasing the engagement with the notch 23 of the stopper cam 19.

As a result, when the sewing machine is stopped, the restoring force stored in the spring 41 due to the slight deformation of the spring 41 causes the stopper 19 to rotate counterclockwise relative to the bushing 8, which is still in a stationary state, and moves the roller 18 into a narrower space. As the belt pulley 5 and bushing 8 are pushed in, they are reconnected via the rollers and begin to rotate, causing the sewing machine to sew one stitch.

When the sewing machine rotates once, the release cam 46 is first stopped by the stopper 48, and the various parts work in the order described above, and the sewing machine stops at a predetermined position.

If you repeat pressing and releasing the controller in the same way, the sewing machine will rotate once and then stop at a predetermined position. While the needle is stopped upwards, move the fabric by the desired amount with both hands to bast it. Can sew.

FIG. 18 shows another embodiment, in which a spring 108 is interposed between the pawl 107 and the side wall 13 of the counterbore surface 12 of the belt pulley 5, and a release cam 109 of the pawl 107 and a recess 1 of the rook 110 are provided.
11 and 112 by the force of the spring 108 without relying on the weight of the pawl 107. In this case, the pawl 107 can engage the recesses 111, 112 no matter where it is located around the upper shaft 6. 112, so a single one is sufficient.

However, it is necessary to form the concave portion 112 of the rook 110 over the entire circumference.

Next, the thread winding operation will be explained.

First, set the operating knob 91 of the selection switch 88 to the normal sewing position (either high or low speed), and
7 in the counterclockwise direction in FIG. 4, the rubber ring 105 is pressed against the knurled surface 106 of the belt pulley 5, and the declutch arm 95 is released and rotated clockwise in FIG. 14 by the spring 99. Since its tip 96 enters the movement path of the cam 24 of the stopper cam 19, it eventually engages with the notch 23 and the rotation of the stopper cam 19 is stopped.

This releases the roller 18 of the declutch device 9,
The belt pulley 5 idles and can perform thread winding.

In this case, the tip 96 of the clutch arm 95 does not engage the release cam 46 at all, so the eave gutter device does not work at all.

By the above operations, in the present invention, it is possible to select and perform normal stitching, single stitch stitching, and thread winding, respectively, and the effects thereof will be explained below.

First, since single-stitch sewing using the device of the present invention can be performed by stepping on the controller, both hands can be used exclusively for guiding the fabric, making the work easier and allowing the fabric to be guided accurately. effective.

In particular, since one stitch can be performed while the sewing machine is stopped for an arbitrary period of time, basting of curved parts and other troublesome parts can be easily performed.

Furthermore, since the connection between the declutch device 9 or the belt pulley 5 and the upper shaft 6 is already released when the sewing machine is stopped, the impact and noise at the time of stopping are small, and no unreasonable force is applied to the sewing machine motor and other driving parts.

Moreover, the long holes 28 and 29 of the stopper cam 19 are connected to the buffer member 3.
1.32, and a member integrated with the upper shaft 6 comes into contact with the buffer member and stops later, so the impact is greatly alleviated.

Furthermore, the stopper cam 19, the release cam 46, the rook 37, and the spring 41 are compactly arranged, and the pawl 11 that enables the sewing machine to rotate again is provided using a part of the belt pulley 5, so that the sewing machine can be used in extremely narrow spaces. It has become possible to install a highly functional single-stitch sewing device in the space at the end.

Moreover, each of these parts can be easily manufactured by molding with synthetic resin or sheet metal processing, has a simple structure, and does not require an electromagnetic solenoid at all, so that it can be provided at low cost.

In addition, since the stopper cam 19 can be provided with sufficient strength, there is no risk of damage even if the handwheel 69 is turned strongly when the sewing machine is stopped in the eaves gutter.

In addition, high-speed sewing and low-speed sewing can be selected using a single operating knob 91, providing good operability.
．． 94, but is supported by a mechanical part, that is, an uneven surface on the outer periphery of the selection cam 81.
Moderation can be maintained reliably and electrical connections can be made good.

Furthermore, in the flywheel 69, the flywheel mounting screws are not exposed to the outside unlike in conventional products, and even if a fairly complicated mechanism is provided on the rear end of the sewing machine as in the present invention, the work of attaching and detaching the flywheel 69 is easy. be.

Further, even if the material is made of synthetic resin, there is no need to tighten screws, so there is no risk of damage due to tightening the screws.

[Brief explanation of drawings]

Fig. 1 is a rear end view of the main parts of the mechanism of the present invention, Fig. 2 is a rear view of the same, Fig. 3 is a vertical sectional view of the main parts, Fig. 4 is a plan view of the same, and Fig. 5 shows the state in which the flywheel is installed. A vertical sectional view, FIG. 6 is a partial group perspective view, and FIG. 7 is a perspective view showing the front side of the sewing machine with a belt pulley.
Fig. 8 is a partially sectional view taken along arrows A-A' in Fig. 3, showing the starting state of one stitch sewing, Fig. 9 is a partially omitted perspective view of Fig. 8, and Fig. 10 is a release cam and rook. Fig. 11 shows a partially omitted perspective view of Fig. 10, Fig. 12 shows a state in which the sewing machine starts to rotate again, and Fig. 13 shows a state in which the sewing machine starts rotating again. FIG. 12 is a partially omitted perspective view, FIG. 14 shows the pincushion state, and FIG. 15 shows the relationship between the rook and the pawl.
FIG. 16 shows the relationship between the stop cam, the release cam, and the pawl, and FIG. 17 shows the pawl depressed into the recess of the release cam. FIG. 18 is a diagram showing the operating state of another embodiment. 6 is an upper shaft, 64 is a presser arm, 65 is a protrusion, 69 is a flywheel, 70 is a boss portion, 71 is an engaging portion, 72 is a hole, and 73 is a pin.

Claims (1)

[Scope of utility model registration request] An engaging portion 71 is formed on the outer periphery of the boss portion 70 of the flywheel 69 and is inflated so that the outer diameter becomes larger at the middle portion and recessed so that the outer diameter becomes smaller at the inner portion.
A hole 72 is formed at the end, and a protrusion 65 of a presser arm 64 which is bent from both ends of a belt wheel presser foot 63 integrally fixed to the upper shaft 6 and has a spring action is used to hold the engagement portion 7.
1 to press and restrain the flywheel 69 in the axial direction, and a pin 73 fixed integrally with the upper shaft 6 to engage with the hole 72 to restrain the flywheel 69 in the rotational direction. .