JPS636234B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Technical Field] The present invention relates to an upper feed mechanism of a sewing machine, and more particularly to a presser foot lifting device thereof.

[Conventional technology]

Conventionally, in a sewing machine equipped with an upper feed dog that cooperates with a lower feed dog to clamp and feed the sewing fabric, when the presser foot is raised to insert the fabric,
Depending on the position of the vertical movement trajectory of the upper feed dog, the lower surface of the upper feed dog protrudes below the presser foot, which has the disadvantage of interfering with the insertion of the cloth.

FIG. 2 is a sectional view of a main part explaining this state. 2 is the presser foot, 3 is the throat plate, 4 is the upper feed dog, 5
2 is a support portion thereof, and 2a is a convex portion provided on the upper surface of the presser foot 2 so as to come into contact with the lower surface of the support portion 5 when the presser foot 2 is raised.

W is a sewing cloth, and when this thickness is large, insertion becomes difficult/impossible.

In order to eliminate the above-mentioned drawbacks of the conventional methods, a presser foot lifting device has been proposed in which the upper feed dog is raised above the lower surface of the presser foot when the presser foot is raised (Jetko Kosho 62 -Refer to No. 32546). FIG. 3 shows a perspective view of the main parts of this proposed device. This mechanism is explained in detail in the cited example above, so a detailed explanation will be omitted, but in FIG. A connecting arm 9 is provided which connects the base end of the presser foot arm 11 to which the presser foot 12 is fixed at the tip, and when a pedal (not shown) connected via the operation chain 42 at the tip of the operating arm 10 is operated. , the connecting arm 9 rotates counterclockwise around the support shaft 8, and the presser foot arm 11 also rotates in the same direction to raise the presser foot 12 from the throat plate, and the presser foot 14
is pushed up against the force of the compression coil spring 15,
The moving body 3 is connected to the pressing body 14 via a connecting rod 35 that is integrated with the pressing body 14.
4 rises along a groove 36 formed under the frame of the sewing machine. FIG. 4 is an enlarged side view of the main part of the connection mechanism between the movable body 34 and the upper feed swing arm 26. When the movable body 34 rises, the upper feed The tip of the swinging arm 26,
Push up against the force of the compression coil spring 33,
The swinging arm 26 rotates counterclockwise around the support shaft 8, and the upper feed movement rod 29 also rotates in the same direction around the support shaft 8 via the support portion 26b, and the upper feed motion rod 29 fixed to the tip thereof rotates in the same direction. Raise the tooth 28 from above the throat plate.
At this time, the height position of the pin 41 that contacts the swinging arm 26 is appropriately set so that the lower surface of the upper feed dog 28 is located above the lower surface of the presser foot 12, as shown in FIG. It is configured so that such a state can be obtained.

[Problem that the invention seeks to solve]

However, in the configuration of such a proposed example, the pressing body 14 of the presser foot arm 11 which is the driving side when transmitting the required motion, and the movable body 34 of the driven side which is driven via the connecting rod 35. Since the offset amount e with respect to the line of action of the force is large, an offset moment acts between the movable body 34 and the square groove 36 on the machine frame side on which it slides, causing twisting, which obstructs smooth movement along with frictional resistance. As a result, there were problems in that the feeding force for driving was reduced and the ability to follow high speeds was lacking.

The present invention was made in view of the above-mentioned problems, and it is an object of the present invention to provide a motion transmission mechanism for the same part that does not generate an offset moment.

[Means for solving problems]

Therefore, the present invention is constructed so that the vertical movement of the pressing body of the presser foot arm is entirely transmitted to the upper feed swinging arm by a stable lever and link mechanism that are not adversely affected by offset moments, etc. be.

〔Example〕

The present invention will be explained below based on the drawings.

FIG. 1 is a perspective view corresponding to FIG. 3 of the above cited example showing an embodiment of the motion transmission mechanism of the presser foot lifting device according to the present invention, and the same or equivalent components as in FIG. 3 are the same or equivalent. They are indicated by symbols, and repeated explanations will be omitted. Note that FIG. 4 shown above is common to this embodiment as well. (However, the moving body 34 is a link 34' (described later) in this embodiment).

In FIG. 1, 50 is a lever A, and 51 is a lever B. Both levers are fixed to both ends of a connecting shaft 35', and the connecting shaft 35' is connected to the machine frame (not shown) of the sewing machine. It is pivoted so that it can rotate around its axis. The free end of the lever A50 is bifurcated in the vertical direction, and the opening 52 has a
A pin 53 fixedly protruding from the pressing body 14' is inserted and engaged to swing the free end of the lever A50 in the vertical direction. Further, a connecting link 34' (a member corresponding to the movable body 34 in FIG. 3) is connected via a pin 54 to the free end of the lever B51 on the opposite side, which swings by the same angle as the lever A50 via the connecting shaft 35'. The other end of this link is connected by a pin 40 to lift the upper feed swing arm 26 via an actuating body 37 and a pin 41, similar to the above cited example in FIGS. 3 and 4. It is composed of Here, in this embodiment, the pin 40 portion at the other end of the connecting link 34' is pivotally supported by a support link 55, and the other end of this link is connected to the sewing machine frame (Fig. (not shown).

In addition, in FIG. 1, the manual lever-related parts 16, 17, for pushing up the pressing body 14 shown in FIG.
18 etc. are omitted. Further, as shown in FIG. Of course, the lower surface of the presser foot 12 is appropriately set so as to be located above the lower surface of the presser foot 12.

Next, the operation of the above configuration will be explained.

When the presser foot 12 and the upper feed dog 28 are in contact with the throat plate, when a pedal (not shown) connected through the chain 42 of the operating arm 10 is depressed, the movement occurs as shown in FIG. As explained in the cited example,
The operating arm 10, the connecting arm 9, and the presser foot arm 11 rotate counterclockwise around the support shaft 8, and the presser foot 1
2 rises from the throat plate, and the pressing body 14' is pushed upward against the force of the compression coil spring 15. Accordingly, the lever A50 is connected to the lever 4, the connecting shaft 35',
The lever B51 is rotated counterclockwise around the axis of the connecting shaft to pull up the connecting link 34'. Thereafter, the upper feed swing arm 26 is lifted up against the force of the compression spring 33 via the pin 40, the operating body 37, and the pin 41, and swings counterclockwise around the support shaft 8 through the groove 8a. This rocking motion is transmitted to the upper feed movement rod 29 via the inverted L-shaped support portion 26b, causing the upper feed dog 28 fixed at the tip to raise the needle 28 onto the throat plate, as shown in FIG. A relational position state as shown is obtained.

In such an operation, the entire movement from the pusher 14' to the swinging rod 26 is transmitted by a stable lever and link mechanism, and moreover,
5' and one end of the support link 55 are pivotally supported on the machine frame of the sewing machine, so it is extremely stable and has little friction, and unlike the conventional example, it is not affected by adverse effects such as stiffness due to offset moments etc. The desired movement can be transmitted without any movement.

In the above embodiment, one end of the link 34' is
The pin 4 at one end of the support link 55 together with the operating body 37
It is obvious that instead of being connected at 0, it may be connected independently in the middle of the support link 55.

[Other Examples]

FIG. 6 shows a perspective view of essential parts of another embodiment of the present invention, and the same or equivalent components as in FIG. 1 are designated by the same or equivalent symbols. The link corresponding to the connecting link 34' in FIG. 1 of the embodiment is 34''.
In the above embodiment, the rise of the pressing body 14'' was transmitted to the link 34' by the swinging of the links 50 and 51 caused by the rotation of the connecting shaft 35', whereas in this embodiment, the lifting of the pressing body 14'' Raise 14" by attaching pin 6 to machine frame F.
Reversing lever 60 pivoted at 1, intermediate link 6
4. The same upward movement as in the previous embodiment is applied to the connecting link 34'' through a second reversing lever 65 which is pivotally supported on the machine frame F by a pin 66. bifurcated opening, 63
is a pin protrudingly provided on the pressing body 14'', and it goes without saying that this embodiment also exhibits exactly the same effects as the previous embodiment.

〔Effect of the invention〕

As described above using the embodiments, according to the present invention, the structure is such that all the vertical movement of the pressing body of the presser foot arm is transmitted to the upper feed swinging arm by a stable lever and link mechanism. As a result, the motion transmission is extremely stable and smooth, and the transmission efficiency and ability to follow high speeds have been improved without being adversely affected by distortion or offset moments.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the motion transmission mechanism of the presser foot lifting device according to the present invention, FIG. 2 is an explanatory diagram of the state of the conventional presser foot, and FIG. 3 is a diagram of the conventional presser foot. A perspective view corresponding to FIG. 1 of an example of a lifting device, No. 4
The drawings are enlarged side views of the main parts of Figs. 1 and 3, Fig. 5 is an explanatory diagram of the state of the presser foot according to the invention, and Fig. 6 is a perspective view of the main parts of another embodiment of the invention. It is a diagram. 8... Support shaft, 9... Connecting arm, 10... Operating arm, 11... Cloth presser arm, 12... Cloth presser foot, 13
...Adjustment screw, 14', 14''...Press body, 24...
...Vertical drive body, 26...Upper feed swing arm, 28...
Upper feed dog, 29... Upper feed movement rod, 34', 3
4″...Connection link, 35′...Connection arm, 37...
Actuating body, 50, 51... Lever A/B, 55...
Support link, 60, 65... Reversing lever, 64...
...Intermediate link.

Claims (1)

[Scope of Claims] 1. A presser foot arm 11 that supports a presser foot at its front end, supports a base at its rear end on a rotatable support shaft, and presses the front end downward by a pressing member; The upper feed swing arm is connected to the drive body and is slidably supported on the support shaft, the rear end is connected to the upper feed movement rod, and the front end is pressed downward by the pressing mechanism, and the upper feed swing arm is linked to the main shaft of the sewing machine. The vertical drive body is fixed to an operating shaft that swings at a constant rate, the operating body is L-shaped and has a pin at one end placed below the front end of the up-feed swing arm, and one end is rotated to the eccentric pin of the vertical drive body. A link is movably connected and the other end is connected to the other end of the actuating body, and a support link is rotatably supported at one end to the machine frame and the other end is rotatably connected to the center of the actuating body. , a plurality of lever mechanisms rotatably supporting the base with respect to the machine frame at a position away from the pressing body, and rotating in conjunction with the vertical movement of the pressing body to transmit motion to the support link; The upper feed mechanism of the sewing machine.