JPH0237793B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a pattern selection device for a pattern stitch sewing machine, and the present invention relates to a pattern selection device for a pattern stitch sewing machine, which selects a cam from among a plurality of built-in pattern cams. Through the contacting cam contactor,
It is used in zigzag sewing machines and the like to create various sewing patterns by transmitting the amount of change in the cam surface to the needle bar.

(Prior Art) Conventionally, this type of device was invented and devised according to the application filed by the present applicant, namely, Utility Model Publication No. 45-25709.
Japanese Patent Publication No. 47-2983 (hereinafter referred to as B technology), and Japanese Utility Model Publication No. 55-34930 (hereinafter referred to as C technology) are known.

In the technique A, in the rotation operation of one dial shaft, the dial rotation angle per pattern is divided, and the cam contactor is separated within the first corner of each.
It is selected within the next rotation angle and engaged with the cam within the last rotation angle. However, since one pattern cam is placed within each limited angle of division,
Naturally, a limit is imposed on the number of pattern cams that can be incorporated into a sewing machine.

In technique B, a spring means is interposed in the interlocking part that transmits the movement operation to the cam contactor, and the cam detachment of the contactor is performed so that it separates once per rotation in synchronization with the rotation of the upper shaft of the sewing machine. ing. Therefore, in this case, there is a delay of approximately one stitch at most from immediately after the cam selection operation lever is operated until the cam is switched.

In the C technique, as shown in FIGS. 3 and 4, one operation shaft 20 simultaneously operates the raising cam 22 for removing the contact 21 and the selection cam 23, and the selection cam 23 operates the removal cam 22 of the contact 21. Spring means 25 is provided in the moving path via the contact body 24, and the contact 21
When the pattern cam 26 is on the periphery of the pattern cam 26 and is prevented from moving due to engagement with the periphery of an adjacent cam, the movement of the pattern cam 26 is delayed by the bending of the spring means 25, and then the release raising cam 22 acts. The contactor 21 is allowed to disengage from the cam circumference and at the same time is moved to a new selected position by the restoration of the spring. This C
The technique complements the A and B techniques described above and has added utility.

(Problems to be Solved by the Invention) However, even in the above technique C, (1) when the movement of the contact to the adjacent pattern cam is prevented, the pressure of the coil spring 20 is applied to the selection dial torque.

(2) It is necessary to lift the selection cam 23 by the amount of movement of the contact, and the slope of the cam becomes steep.

(3) The contact body 24 may be pushed on one side, causing twisting, which may impair the smoothness of operation.

Based on the above reasons, the operation of the pattern selection dial 27 tends to be somewhat difficult. In addition, in order to obtain good operability of the contact body 24, attention must be paid to the dimensional accuracy, which is problematic in that manufacturing is troublesome.

The present invention aims to eliminate these undesirable points.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention takes the following measures. That is, a pair of selection cams, a pair of contacts, and a pair of two selection arms via a pair of selection arm supports are respectively arranged on each support shaft provided parallel to the support shaft of the pattern cam group. The selection cam is rotated by rotating the pattern selection dial, and the pattern cam is selectively selected via the contacts.

The two selection arms overlap with the selection arm support as a fulcrum, one of them (large) has an engagement pin at one end that moves the contact in the axial direction, and the other one (small) has a selection arm that moves the contact in the axial direction. The contact engaging pin is moved via a pin that engages with the cam lift of the cam, and the amount of movement of the contact engaging pin is expanded in accordance with the difference in distance between the two pins and the selected arm support. Then, a coil spring was stretched between both selection arms, and a selection arm spring was stretched between a pair of other selection arms (small).

(Function) When the pattern selection dial is rotated according to a predetermined angle, the selection cam is rotated by the specified angle due to the gear engagement drive. Therefore, one selection arm (small) has a pin provided on the arm that is in contact with the cam lift surface of the selection cam, and moves in accordance with changes in this cam surface.

At this time, the other selection arm (large) is moved using the pin of the selection arm (small) as a guide, so the amount of movement of the pin at the tip (which engages the contact and moves it laterally) is , the movement of the selected arm (small) pin is theoretically expanded.

In addition, when the lateral movement of the contact is blocked due to engagement with the peripheral edge of an adjacent pattern cam, the guide member moves the contact onto the periphery of the pattern cam via the disengagement upper cam that is linked to the operation of the pattern selection dial. At this time, when operating the selection dial, the coil spring pressure stretched between the large and small selection arms is loaded as torque, but this load is applied to the selection dial that is provided separately. By selecting the arm spring between (large), the reduction is reduced to the extent that it is almost canceled out.

(Example) An example of the present invention will be described below based on FIGS. 1 and 2.

1 is a mounting frame for the device of the present invention, and 2 is a pattern cam shaft to which a large number of pattern cams 3 and feed control cams 3' are attached.

Reference numerals 4, 5, and 6 denote a selection cam shaft, a contact shaft, and a selection arm shaft provided in parallel with the pattern cam shaft 2, and each of these shafts has a selection cam 7 loosely fitted on the shaft. Contacts 8, 8' movable on the axis and selective arm supports 9, 9' fixed on the axis are provided, respectively. 10 is a pattern selection dial shaft to which a pattern selection dial 11 is fixed, 12, 12' and 13, 1.
3' are a selection arm (large) and a selection arm (small), respectively. Both selection arms 12, 12' and 13,
The base of 13' is swingably supported by the selective supports 9, 9' with support members 14, 14' as fulcrums.

Reference numerals 15 and 15' denote pins fixed to one end of the selection arms (small) 13 and 13', and the intermediate portion thereof is connected to the through holes 12a and 12 provided in the selection arms (large) 12 and 12'.
a' and guides the movement of the arms 12, 12'. The tips of the pins 15, 15' engage with the cam lift surfaces 7a, 7a' of the selection cam 7, respectively.

16, 16' are pins fixed to one end of the selection arm (large) 12, 12', the pins 16, 16' are opposite in direction to the pins 15, 15', and , 8' groove 8a (8a') provided in the boss part
is engaged in.

17, 17' are coil springs stretched between the selection arms (large) 12, 12' and (small) 13, 13', and 18 is a selection arm stretched between the selection arms (large). It's a spring.

Next, the operation of this embodiment will be described. As mentioned earlier, when the pattern selection dial 11 is rotated, the selection cam 7 is rotated through the meshing drive of a selection gear and a selection cam gear (not shown).

Then, the selection arm (small) 1
3 and 13' swing.

Along with this, the selection arms (large) 12, 12' also swing,
The contact 8,
8' is moved on the contact shaft 5 in the axial direction.
Symbols l and L in Fig. 2 indicate the center distances between the support member 14 and the pins 13 and 16 in the figure, respectively, and there is a rocking (movement) between these two pins by the L/l ratio.
The amount is expanded. This will be explained in the next effect column, but the amount of swing expansion is the cam lift 7 of the selection cam 7.
It is possible to replace the points a and 7a' by reducing them. Further, in conjunction with the operation of the pattern selection dial 11, a contact detachment cam (not shown) is operated, and the contact 8 is separated in the direction indicated by the arrow in FIG. 2 via the guide member 19. At this time, if the movement of the contactor 8 is blocked by engagement with the peripheral edge of the adjacent cam, the tension of the coil springs 17, 17' is applied to the dial rotation torque. However, this spring load is
Since the movement of 8' is sufficient, it is absorbed by the selection arm spring 18 and does not greatly affect the dial torque.

〔Effect of the invention〕

In order to make the operation of the selection dial easier, which is one of the problems of the present invention, it has been considered to make the slope of the cam longer and the slope gentler, but in this case, the number of patterns that can be obtained with one rotation of the dial will be reduced. . Even if the method allows for a large number of patterns, the structure will be large and the handling operation will be cumbersome.

In addition, in order to prevent sliding defects due to twisting of the contact body, there is a method of using a bearing in the bearing portion of the contact body, but this method requires an increase in the number of parts, ensuring accuracy, etc., and is expensive.

In the present invention, (1) the amount of movement is expanded by the L/l ratio between the selection arm (large) that moves the contact and the selection arm (small) that is moved by the selection cam, and the related selection The slope of the cam can be made gentle, thus reducing dial torque.

(2) Since the pins of the selection arm (large) and selection arm (small) are in opposite directions, the tilting load applied to each selection arm is distributed, preventing twisting and not affecting dial torque.

(3) When the contactor movement to the adjacent pattern cam is blocked, coil spring pressure is applied to the selection dial torque, but this load is absorbed by the selection arm spring as the minimum amount that allows the contactor to move. Since they cancel each other out, there is little effect on dial torque. And these configurations are simple,
It is also easy to manufacture.

[Brief explanation of drawings]

FIG. 1 is an explanatory plan view of the structure of the apparatus of the present invention, FIG. 2 is a side view (partially sectional) of FIG. 1, and FIGS. 3 and 4 are explanatory views of the prior art. 3... Pattern cam, 7... Selection cam, 8... Contact, 9... Selection arm support, 11... Pattern selection dial, 12... Selection arm (large), 13... Selection arm (small), 14... Support member, 15, 16... Pin,
17...Coil spring.

Claims (1)

[Scope of Claims] 1. A pattern stitch sewing machine that obtains various sewing patterns according to the profile of a cam selectively selected from among a plurality of pattern cams including a swing width cam and a feed cam, comprising: A pair of selection cams, a pair of contacts, and a pair of selection arm supports are respectively disposed on each support shaft parallel to the spindle of the pattern cam, and the pair of selection cams are rotated by operation of a pattern selection dial. The pair of contacts are movably pivoted on the support shaft, and the distance between the pins of the pair of selection arms and the selection cam for moving the contacts is determined by using the selection arm support member as a fulcrum. L/
A pattern sewing machine is provided with means for obtaining an enlargement ratio of l, and a coil spring is provided between the two selection arms, and a selection arm spring is provided between a pair of other selection arms that are moved via a cam lift of a selection cam. Pattern selection device. 2. In a pattern sewing machine that obtains various sewing patterns according to the profile of a cam selectively selected from among a plurality of pattern cams consisting of a swing width cam and a feed cam, the support shaft of the pattern cam and A pair of selection cams, a pair of contacts, and a pair of selection arm supports are arranged on each of the parallel support shafts, and the pair of selection cams are rotatably supported by operation of a pattern selection dial, and the selection cams are rotatably supported by the operation of a pattern selection dial. The pair of contacts are movably supported on the support shaft, and are moved using the selection arm support member as a fulcrum via the distance between the pins of the pair of selection arms that move the contacts and the cam lift of the selection cam. L/
a coil spring is provided between the two selection arms, and a selection arm spring is provided between a pair of other selection arms that move via a cam lift of the selection cam; A pattern selection device for a pattern sewing machine in which the provided pins are arranged in opposite directions.