JPH0111178Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Object of the invention) The present invention relates to a feed dog sinking device for a sewing machine.

(Field of Application of the Invention) The technology of the present invention can be used not only in sewing machines but also as means for changing the position of operating parts in general small mechanical devices.

(Prior art) Conventionally, as a feed dog sinking device for sewing machines, the
No. 55-25892 is known.

This technique will be explained below with reference to FIG. In the figure, 31 is a feed base that swings back and forth via a horizontal feed cam (not shown) on a camshaft 32;
Reference numeral 3 denotes a feed dog fixed to the feed base 31, and the figure shows a state in which the feed dog 33 is floating above the upper surface of the throat plate 34. 35 is a rotatable operating arm on the hook driving shaft 36, and the operating arm 35 is driven by a gear from the hook driving shaft 36. It comes into contact with the upper surface of the vertical feed cam 37 on the camshaft 32. 38 is a switching arm, and axis 3
9 is pivotally attached to the distal end of the operating arm 35, and both of them swing up and down about the shuttle drive shaft 36.

Reference numeral 40 denotes a roller supported by the switching arm 38, and in the illustration, the downward protrusion 3 of the feed table 31 is placed on the roller 40.
1a is in contact with it. When the shuttle drive shaft 36 rotates in this state, the feed dog 33 protrudes and retracts from the upper surface of the throat plate 34, performing a known feeding motion.

In this technology, the feed dog 3 is used for stitching etc.
3, open the opening/closing plate 41 and press the upper operating portion 38a of the switching arm 38. Then, the roller 40 is positioned as indicated by the two-dot chain line (lower left in the figure). Here, the engagement pin 42 engages in the recess 44b of the holding portion 43, and the above-described position is maintained.

Therefore, the protruding portion 31a of the feed base 31 in contact with the roller 40 also moves down due to the bias of a spring (not shown), and the feed dog 33 sinks below the throat plate 34.

In order to float the feed dog 33 again, the lower operating portion 38b of the switching arm 38 is pressed in the opposite manner to the above to return it to the state shown.

(Problems to be Solved by the Invention) In the feed dog sinking and floating switching operation of the above-mentioned conventional technology, when the feed dog is sunk, it can be done by a relatively light pressing operation of the switching arm, but when it is raised, However, since the switch was made against the pressure of the presser foot, it was difficult to operate.

The present invention solves the above problems and improves the operability of switching between sinking and raising the feed dog.

[Structure of the idea]

(Means for Solving the Problem) The solution in the present invention is to use a vertical feed cam fixed on the rotary hook shaft so that the vertical feed cam surface and the perfect circular cam surface equal to the minimum diameter part of the cam surface. It has a superimposed two-layer structure, and one end of the vertical feed arm, which is always biased in one direction by spring pressure, selects and locks one of the two-layer cam surfaces using a switching lever means. I made it. The compressive force of the biasing spring is used to switch the feed dog upward.

(Function) The function of the above-mentioned constituent means will be explained based on the attached FIGS. 1 to 6.

That is, when the sewing machine is rotated with the switching lever 19 in the state shown in FIG.
gives a back and forth reciprocating motion. On the other hand, the hook shaft 1 also swings and rotates, and the vertical feed action arm 12 is operated by the vertical feed cam surface 5a.
The feed table 9 is caused to perform a swinging motion about the working arm shaft 11, and the feed table 9 is made to perform a swinging movement about the feed table shaft 8 through the adjusting screw 15 fixed to the bent portion 12c of the vertical feed working arm 12. make them do Therefore, feed base 1
0 moves up and down and appears and disappears on the upper surface of the throat plate 25. This back and forth movement performs a known feeding motion.

To lower the feed dog 10 below the throat plate 25 for stitching or the like, the switching lever 19 is rotated clockwise in FIG. 1. Then, the side surface 22a of the window hole 22 comes into contact with the pin 13, the vertical feed action arm 12 moves to the left against the compression spring 18, and the pronged portion 12a is moved relative to the perfect circular cam portion 5b of the vertical feed cam 5. Then, the pronged portion 12a and the vertical feeding arm 12 are rotated by tensile force to the position shown by the two-dot chain line in FIG. Therefore, the feed dog 10 sinks below the throat plate 25. In this state, the steel ball 23 is locked in the locking recess 19b of the switching lever 19, and the switching lever 19 is locked.
will be locked.

When performing normal sewing from the depressed state of the feed dog 10, move the switching lever to the position shown in FIG.
9 is rotated, but at this time, the window hole 22 appropriately provided in the switching lever 19 does not come into contact with the pin 13 of the vertical feed arm 12, and the switching operation can be performed with a light force against the compression spring 24. Vertical feed operation arm 1
2, during one rotation of the sewing machine, the pronged portion 12a moves in a phase opposite to the minimum diameter portion of the vertical feed cam 5a until it comes into contact with the E-ring 17 due to the pressure of the compression spring 18, and normal sewing is possible. Become. Therefore, regardless of the presser pressure acting on the feed dog 10, the switching lever 19 can be used to switch the feed dog 10 upward.

(Example) Examples of the present invention will be described below with reference to the attached drawings.

In the figure, reference numeral 1 denotes a hook shaft rotatably provided in a free arm 2 of the sewing machine.A hook (not shown) is attached to one end of the hook via bevel gears 3 and 4. A feed cam 5 is fixed.
The vertical feed cam 5 includes a cam 5a and a cam 5.
A perfect circular cam 5b is formed which is equal to the minimum diameter portion of a.

A horizontal feed shaft 6 is rotatably supported at both ends by a pen center 7, and a feed shaft 8 is fixed to arms 6a and 6b. Reference numeral 9 denotes a feed base to which a feed dog 10 is fixed, and is rotatably supported on the feed base shaft 8. Further, at the other end of the horizontal feed shaft 6, a horizontal feed arm (not shown) is connected to a feed adjuster via a fork, and by changing the inclination angle of the feed adjuster, the feed dog 10 is given back and forth reciprocating motion. giving.

Reference numeral 11 denotes a working arm shaft fixed within the free arm 2, on which a vertical feed working arm 12 is rotatably supported. The vertical feed action arm 12 is provided with a protrusion such that its pronged portion 12a abuts against the vertical feed cam 5.
A tension spring 14 is adjusted between the hook 12b and the carriage 9. Also, an adjustment screw 1 is attached to the bent portion 12c.
5 is fixed by a nut 16. The head 15a of the adjusting screw 15 is brought into contact with the portion 9a of the feed base 9 under the tension of the tension spring 14.

Also, pin 1 is attached to the pusher 12d of the vertical feed arm 12.
3 is fixed.

An E-ring 17 is attached to an appropriate position on the working arm shaft 11, and a compression spring 18 is provided on the same shaft 11 so that the vertical feed working arm 12 comes into contact with the E-ring 17. In this state, the Katamata part 12a
is opposed to the cam 5a, and the feed dog 10 protrudes upward from the throat plate 26, as shown in FIG. A switching lever 19 is rotatably supported by a boss 20a of a bed cover 20 attached to the free arm 2, and its sliding in the axial direction is restricted by a screw 21 and a nut 25. The switching lever 19 is provided with locking recesses 19a and 19b on the lower surface, and the pressure of the compression spring 24, which is heavier than the compression spring 18 disposed in the hole 20b of the bed cover 20, is constantly applied to either one of the locking recesses. The received steel ball 23 is involved. A knob portion 19c is formed at the tip of the switching lever 19, and the knob portion 19c protrudes into the front recess 20c of the bed cover 20 so that it can be operated from outside the sewing machine.

Further, the replacement lever 19 is provided with a window hole 22 of an appropriate size, and an iron ball 23 is provided in the locking recess 19a.
is engaged, and the vertical feed action arm 12 is in the E position.
At the position where the pin 13 contacts the ring 17, the pin 13 is inserted into the window hole 2.
It has an appropriate clearance A for 2.

When the switching lever 19 is rotated clockwise in FIG. 1, the pin 13 comes into contact with the right side surface 22a of the window hole 22, and the vertical feeding arm 12 moves to the left against the compression spring 18. Then, with the cantilevered portion 12a disengaged from the cam 5a of the vertical feed cam 5 and facing the perfect circular cam 5b, the steel ball 23 is engaged in the locking recess 19b of the switching lever 19, and the switching lever 19 is locked. Ru.

Note that 26 indicates a presser foot, and 27 indicates a presser bar located below by a presser spring (not shown).

[Effect of idea]

The conventional sinking mechanism for the feed dog had problems with ease of assembly and wear resistance, but with the present invention,
By providing the working arm, the vertical feed cam and the shaft are fixed, eliminating the drawbacks of vibration and wear.Since the vertical feeding cam and the horizontal movement of the feed base are separated, the cam shape is simplified, and the working arm Due to the position of the support shaft, the load applied to the vertical feed cam can be reduced due to the dimensional ratio between the cam contact position and the feed base contact position, and the switching lever can be assembled separately, improving ease of assembly.
This has the effect of reducing the number of man-hours.

[Brief explanation of the drawing]

Fig. 1 is a plan explanatory diagram of the configuration of the device of the present invention, Fig. 2 is a rear view of Fig. 1, and Figs. 3 and 4 are cross-sectional views taken along lines A-A and B-B of Fig. 1, respectively. directional view,
Figure 5 is a plan view of Figure 4, and Figure 6 is the C of Figure 5.
-C line sectional view, and FIG. 7 is an explanatory diagram of the prior art. 1... Hook shaft, 5... Vertical feed cam, 6... Horizontal feed axis, 9... Feed base, 10... Feed dog, 11...
... Operating arm axis, 12... Vertical feed action arm, 13...
Pin, 18...compression spring, 19...switching lever.

Claims (1)

[Scope of claim for utility model registration] A hook shaft rotatably supported on the sewing machine bed;
A vertical feed cam consisting of two overlapping layers: a vertical feed cam portion fixed to the hook shaft and a perfect circular cam portion having the same diameter as the smallest diameter portion of the cam portion; a working arm shaft fixed to the bed portion; and a working arm shaft fixed to the bed portion. a vertical feeding arm that is biased in one direction by a compression spring at the top and is rotatable and slidable in the axial direction; one end of the vertical feeding arm is engaged with the vertical feeding cam;
The other end is connected to the vertical action point of the feed base via a fine adjustment member, and one end of the vertical feed action arm is selectively engaged and held with either one of the two overlapping layers of the vertical feed cam. The feed dog of the sewing machine is configured to include a switching lever means, and the feed dog is lowered by forced operation of the switching lever, and the feed dog is raised by the operation of the switching lever and the pressure of the compression spring. Device.