JPH0243350Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field This invention relates to a needle vertical movement device for a sewing machine, and more specifically, it is concerned with a small sewing machine with a new structure that is significantly different in design concept from conventional sewing machines. , is equipped with a mechanism that converts the rotation of the main shaft of the sewing machine into a swinging motion of a lever via a cylindrical cam, and further converts the swinging motion into vertical and reciprocating motion of a sewing needle via a guide provided in the sewing machine frame. This invention relates to a needle vertical movement device for a sewing machine configured to facilitate threading.

Prior Art The needle drive mechanism in commonly used household sewing machines and industrial sewing machines converts rotation from the main shaft of the sewing machine into vertical and reciprocating movement of the needle bar through a thread take-up crank, needle bar crank rod, needle bar holder, etc. However, since this mechanism is inevitably complicated and large, there is a limit to how compact the entire sewing machine can be made.

By the way, the present applicant has now proposed a new small-sized sewing machine that is completely different in design from conventional household sewing machines and the like. This small sewing machine was developed for personal use so that it can easily perform simple sewing, and its mechanical design concept is significantly different from that of conventional sewing machines, with an extremely small and compact exterior configuration. It's tied up. Regarding the device for driving the sewing needle up and down, the complicated and large mechanism described above cannot currently be employed due to space constraints.

Furthermore, this type of small-sized sewing machine generally has the disadvantage that the distance between the upper arm and the sewing machine bed is small, making it extremely difficult to thread the sewing machine. This also means that the operation when replacing the sewing needle becomes easier.

Purpose The present invention is to develop a small and simple needle vertical drive device for a small sewing machine with a mechanism that has a design concept that is significantly different from that of conventional sewing machines, as described above, and to be able to do so in a limited space. It is also an object of the present invention to make it possible to incorporate the sewing machine into the sewing machine, and to facilitate threading of the sewing needle and replacing the sewing needle.

Embodiments Next, the details of the needle vertical movement device of the sewing machine according to the present invention will be described in detail below using preferred embodiments and with reference to the accompanying drawings. Fig. 1 is an exploded perspective view showing the main parts of the needle vertical movement device of a sewing machine according to the present invention, and Fig. 2 is a partially cutaway longitudinal section showing the overall schematic structure of a small sewing machine equipped with the device according to the present invention. It is a front view.

As is clear from the overall structure shown in FIG. 2, the small sewing machine 10 in which the needle vertical movement device according to the present invention is implemented has an upper arm 12, a lower arm 14, and a pedestal 16 as a whole in a box shape. A sewing machine bed 18 is formed on the upper surface of the lower arm 14. A cover body 20 is attached to the upper arm 12 so as to be openable and closable, and a needle vertical movement device according to the present invention is disposed within the arm 12 and is driven by the main shaft 22 of the sewing machine. A sewing needle 24 is reciprocated by a needle vertical movement device which will be explained in detail later.
When the thread is lowered, it enters the needle hole of the throat plate 26 provided on the sewing machine bed 18 and touches the vicinity of the thread catcher 28 (indicated by the two-dot chain line in FIG. 2) disposed below the throat plate 26. pass. This thread catcher 2
Reference numeral 8 typically comprises a horizontal rotary pot, which receives power from an electric motor (not shown) and is capable of horizontal forward and reverse rotation within a predetermined center angle range. The thread catcher 28 may be a looper instead of a rotary shuttle as long as it catches the thread loop formed on the sewing needle 24.

As shown in FIGS. 1 to 5, a sewing machine frame 30 having the shape shown is disposed within the upper arm 12. As shown in FIGS. Describing the form of this sewing machine frame 30,
As shown in FIG. 1, the machine frame 30 is a frame body formed by bending a metal plate into a U-shape as a whole.For convenience of explanation, the end piece located on the sewing machine head side is 30a, and the opposite end piece is 30a. The piece 30b and the side piece 30b which integrally connects both end pieces 30a, 30b.
It is assumed that the instruction is 0c. The sewing machine frame 30
A guide body 32 having the shape shown in the figure is arranged on the front surface of the end piece 30a, and is fixed upright via appropriate fastening means such as bolts 33. This guide body 32
is provided for vertically guiding the needle holding member 34, which will be described later.
As a result of the opening portion 35 being formed in the direction perpendicular to the support shaft 40 of the
a, 32b are defined.

Further, a notch 37 is recessed in the other side of the guide body 32, that is, in the upper part of the side of the needle holding member 34 where the open part 35 is not formed. This notch 37 is provided to allow the needle holding member 34 and sewing needle 24 to rotate about the support shaft 40 through the open portion 35, as will be described later.

A needle holding member 34 to which a sewing needle 24 is attached is inserted between both guide bars 32a and 32b of the guide body 32 so as to be able to reciprocate up and down. This needle holding member 34
As shown in FIG. 1, it has a block shape, and the sewing needle 24 can be detachably attached to the lower end with a screw 38. A support shaft 40 is horizontally inserted into the side surface of the needle holding member 34, with both ends thereof extending outward, and an arcuate recessed portion is provided at the top to allow elastic engagement of an elastic holding piece 39, which will be described later. 34
A is recessed.

A through guide groove 42 is vertically provided in the one guide bar 32a, and one end 40a of the support shaft 40 of the needle holding member 34 is formed in the through guide groove 42.
is fitted in a slidable manner. A guide groove 44 is vertically provided in the other guide bar 32b, and the other end 40b of the support shaft 40 of the needle holding member 34 is slidably fitted into this groove. As a result, the needle holding member 3
4 is between both guide bars 32a and 32b,
It can reciprocate up and down while being guided by both grooves 42 and 44. Note that one end 4 of the support shaft 40
As shown in FIGS. 4 and 5, the tip of the bar 0a is made to protrude outward from the side surface of the guide bar 32a, and is fitted into and engaged with a long hole 50 of a swing lever 48, which will be described later. ing.

Further, as shown in FIG. 1, a rectangular notch 41 is bored at the top of the front end piece 30a of the sewing machine frame 30. Furthermore, as shown by the two-dot chain line, a straight substrate 39a and a curved portion 3 having a predetermined radius of curvature are provided.
An elastic holding piece 39 consisting of 9b is separately prepared,
The elastic holding piece 39 has a straight base plate 39a disposed on the back surface of the end piece 30a, and the bolt 3
3 is attached and fixed to the guide body 32. Further, the curved portion 39b positionsly faces the notch 41 of the end piece 30a and protrudes toward the front of the end piece 30a (toward the sewing machine head side). As will be described later, the curved portion 39b that protrudes in this manner is formed at the top of the needle holding member 34 when the needle holding member 34 is rotated approximately 90 degrees clockwise for threading or replacing the sewing needle 24, for example. The needle holding member 34 is retained in a fixed position by resiliently engaging with the recessed portion 34a.

Next, on the side piece 30c of the sewing machine frame 30, approximately L
A swinging lever 48 formed in the shape of a letter is attached to its horizontal axis 4.
6 is inserted into the through hole 78c, so that it can swing freely. The swing lever 48 is comprised of a long lever piece 48a provided at one free end and a short lever piece 48b provided at the other free end. An elongated hole 50 is formed in the elongated lever piece 48a, and the support shaft 40a projecting and extending from the needle holding member 34 is fitted into and engaged with the elongated hole 50.
An operative connection with a swing lever 48 is provided. Further, the short lever portion 4 of the swing lever 48
A driven protrusion 52 is protruded and fixed to 8b, and this driven protrusion 52 is adapted to engage with a cam surface 56 of a drive cam 54 that interlocks with the main shaft 22 of the sewing machine. The drive cam 54 is a type of cylindrical cam, and is designed to rotate once during one reciprocating movement of the sewing needle 24, and the cam surface 56 is formed in the form of a spiral groove on the outer periphery of the drive cam 54. It is set up. The drive cam 54 is also rotationally driven with the rotation of the sewing machine main shaft 22 connected to an electric motor (not shown), and the swing lever 48 is moved along the horizontal shaft 46 in cooperation with the driven protrusion 52 that engages with the cam surface 56 of the drive cam 54.
It swings at a predetermined central angle around . Therefore, the pivot 40a fitted into the elongated hole 50 provided in the swing lever 48 (elongated lever piece 48a) is also given a swing motion, and the needle holding member 34 and sewing needle 24 are moved between the pair of guide bars 32a. , 32b while being guided by the respective guide grooves 42, 44 and reciprocating up and down.

In addition, in FIGS. 2 and 4, reference numeral 5
Reference numeral 8 indicates a workpiece cloth feeding mechanism that operates in conjunction with the needle vertical movement device according to the present invention. This processing cloth feeding mechanism 58
As shown in FIG. 4, the rubber roller 58 is substantially composed of a rubber roller, and this rubber roller 58 is elastically pressed into contact with the work cloth (not shown) placed on the throat plate 26 and rotated in one direction. By being driven, a predetermined feed is applied to the work cloth. For example, an operation frame 60 is inserted into the sewing machine frame 30 via a support shaft 62, and this operation frame 60
A rubber roller 58 is rotatably supported. Further, a torsion spring 64 is commonly inserted through the support shaft 62 and applies a counterclockwise elastic force to the operating frame 60 in FIG. 4. A second swing lever 66 connected to the main shaft 22 of the sewing machine swings the illustrated sector gear 68 with respect to the operation frame 60, and a gear 7 coaxially connected to the rubber roller 58.
0 and the sector gear 68, the rubber roller 58 (incorporating a one-way clutch) is rotated in a predetermined direction.

Function Next, the function of the needle vertical movement device of the sewing machine according to the present invention will be explained. When the electric motor is driven, its rotation is caused by a series of gears (none of which are shown).
It is transmitted to the sewing machine main shaft 22 via. Note that the rotary hook 28 shown in FIG. 2 is also rotationally driven in synchronization with the vertical reciprocating movement of the sewing needle 24 via a power transmission mechanism (not shown).

When the main shaft 22 of the sewing machine rotates, the drive cam 54 attached to the tip of the main shaft rotates, and the driven protrusion 52 engaged with a cam surface 56 recessed in the drive cam 54 moves the swinging lever 48 horizontally under the action of the cam. 46 at a predetermined central angle. A long hole 50 formed in the long arm piece 48a of the swing lever 48 is provided with the needle holding member 3 to which the sewing needle 24 is attached.
Since the pins 40a of No. 4 are inserted and operatively connected, the swinging motion of the swinging lever 48 is converted into a linear reciprocating motion, and the needle holding member 34 (and the sewing needle 24) is attached to each of the guide bars 32a, 32b. It is guided by guide grooves 42 and 44 to smoothly reciprocate up and down. The drive cam 54, which is interlocked with the main shaft 22 of the sewing machine, rotates once while the sewing needle 24 makes one reciprocating movement up and down. Therefore, under the cooperation of the sewing needle 24 and the rotary hook 28, the needle thread is captured in a suitable manner, and reliable sewing is achieved. Furthermore, this needle vertical movement device is smaller and has a simpler structure than the crank-lock type mechanism employed in ordinary home sewing machines, etc., so that the installation space can be greatly reduced.

Further, when passing the upper thread through the eye hole 72 of the sewing needle 24 or when replacing the sewing needle 24, the needle holding member 34 is raised to the upper limit along the guide body 32, and then the needle holding member 34 and the sewing needle 24 are Gives rotational force in the direction. At this time, the guide body 32 is formed with the open part 35 on one side in the direction orthogonal to the support shaft 40 and the notch part 37 on the other side, as described above, so that the needle holding member 34 is It is allowed to rotate clockwise around the support shaft 40, as shown in FIG. 3, and rotates approximately 90 degrees after passing through the opening 35. As the needle holding member 34 rotates, a curved portion 39 facing the notch 41 formed in the end piece 30a of the sewing machine frame 30 and protruding toward the sewing machine head side.
b (of the elastic holding piece 39) is the needle holding member 34
However, the curved portion 39b is finally elastically fitted and locked into the recessed portion 34a formed at the top of the needle holding member 34. Therefore, since the needle holding member 34 is elastically retained at a predetermined rotational position, threading the sewing needle 24 and replacing the sewing needle can be accomplished extremely easily.

In this embodiment, the sewing needle 24 is attached to the needle holding member 34.
Although the sewing needle 24 is directly fixed by the bolt 33, it is of course possible to attach the sewing needle 24 to a needle bar (not shown) and fix this needle bar to the needle holding member 34. be.

Effects As explained in detail above, the present invention allows the sewing machine's needle up-and-down drive device to be made compact and simple, making it suitable for small-sized sewing machines whose design concept is significantly different from conventional sewing machines. It has become possible to incorporate it in an extremely small and compact manner. In addition, by simply rotating the needle holding member 90 degrees relative to the guide body, threading the sewing needle and replacing the needle can be easily performed, which significantly improves operability when using the sewing machine. It has the following useful effects.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing the main parts of the needle vertical movement device of a sewing machine according to the present invention, and Fig. 2 is a partially cutaway longitudinal section showing the overall schematic structure of a small sewing machine equipped with the device according to the present invention. 3 is an explanatory view showing a state in which the needle holding member is rotated 90 degrees clockwise for thread threading and is elastically locked by an elastic holding piece in the needle vertical movement device according to the present invention; FIG. 4 is a left side view of FIG. 2 with the exterior such as the upper arm removed, and FIG. 5 is a plan view of FIG. 2 with the exterior such as the cover body removed. 22... Sewing machine main shaft, 24... Sewing needle, 30...
Sewing machine frame, 32... Guide body, 34... Needle holding member, 35... Opening part, 37... Notch part, 39...
Elastic holding piece, 40... Support shaft, 46... Horizontal shaft, 4
8... Swing lever, 54... Drive cam, 56...
cam surface.

Claims (1)

[Claims for Utility Model Registration] (1) A drive cam 54 that rotates in conjunction with the rotation of the sewing machine main shaft 22, and a cam surface of the drive cam 54 that is pivotally supported by a horizontal shaft 46 disposed on the sewing machine frame 30. 56; a needle holding member 34 having a horizontal support shaft 40 operatively connected to the swinging lever 48; and a needle holding member 34 to which the sewing needle 24 is removably attached; The support shaft 40 is arranged on the sewing machine frame 30 to guide the support shaft 34 in the vertical direction.
a guide body 32 having an open portion 35 formed on one side in a direction perpendicular to the needle 32; a notch 37 formed on the other side of the guide body 32 to allow the needle to rotate through the opening 35; (2) When the needle holding member 34 and the sewing needle 24 are rotated, an elastic holding piece 39 for holding the rotational position engages with the needle holding member 34 through the notch 37. Range 1
Needle vertical movement device for the sewing machine described in Section 1.