JPH0630152Y2 - Sewing machine clutch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Use) The present invention relates to a clutch device for engaging and disengaging an upper shaft and a pulley in a domestic sewing machine.

(Prior Art) Conventionally, as an apparatus of this kind, as shown in FIG.
The technology described in Japanese Patent No. 0417 is known. That is, both the pulley 23 having the concave portion 22 supported by the main shaft 21 and the operation knob 26 having the projection 25 which is always biased inward by the spring pressure 24 at the end of the main shaft are brought into contact with each other, and the operation is performed. The knob 26 is operated to engage or disengage the projections and the recesses of the two, thereby engaging and disengaging the main shaft and the pulley.

(Problems to be Solved by the Invention) However, the above conventional technique has the following disadvantages.

That is, when the main shaft and the pulley are disengaged, the actuating knob must first be pulled out against the spring pressure, and then it must be rotated. That is, the operation requires two movements.

Further, since the engagement / disengagement portions are provided at three places on the circumference, it is necessary to wait until the main shaft rotates up to 120 ° until engagement, and the engagement timing is delayed. And the device becomes large and requires a certain amount of space.

The present invention is intended to solve the above-mentioned drawbacks.

[Constitution of device]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides means for engaging and disengaging the upper shaft and the pulley by one rotation operation of the switching knob.

That is, a handwheel provided with a clutch pawl biased in one direction was brought into contact with a pulley having a recessed portion mounted on the upper shaft. Then, a clutch switching plate having a switching knob portion, an operation cam portion, and the like was rotatably attached to this handwheel.

(Operation) The clutch pawl provided on the handwheel and urged in one direction normally has its tip engaged with one of the recesses provided in the pulley by spring pressure. This brings the pulley into engagement with the upper shaft.

When the switching knob located in this state is rotated in the opposite direction, the switching cam rotates accordingly, and the clutch claw abutting on the switching cam also rotates to engage with one of the pulley recesses. The leading end portion of the rod is lifted to engage and disengage.

Further, when the switching knob is returned to the original position, the contact position of the clutch pawl with the rotating switching cam returns to the original position, and the tip end of the clutch pawl automatically pushes into one of the pulley concave portions due to the spring pressure. Then, the engagement relationship between the pulley and the upper shaft is restored to the normal state.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS.

In the figure, 1 is a machine frame, 2 is an upper shaft, and on the upper shaft 2, a pulley 4 driven by a timing belt 3 of a motor (not shown) is restricted from axial movement by E-shaped rings 5 and 6. It is supported.

A large number of recesses 4a are provided on a part of the pulley 4 (on the right side in the drawing) with which a clutch claw 7 described later in detail engages.

Further, a handwheel 9 having a concave portion 9a which can be inserted into a pin 8 press-fitted into the upper shaft 2 at an end portion of the upper shaft 2.
Is attached so as to rotate integrally with the upper shaft 2 by a holding screw 10 (FIGS. 1-2).

The handwheel 9 opposite the pulley 4 is constantly pressed to the pulley 4 side by the clutch pawl pressing spring 11 provided in the clutch pressing spring hole 9b, and the clutch pawl operating cam 12a of the clutch switching plate 12 is used. The clutch claw 7 that rotates by an arbitrary angle and engages with and disengages from the recess 4a of the pulley 4 is assembled by the clutch claw pin 13 (FIGS. 2 and 3).

Further, as shown in FIGS. 4 and 5, the clutch switching plate 12 has a switching knob portion 12b, and a plurality of guide bosses 9c are spit washers 14 in the same direction as the rotation of the handwheel 9. It is rotatably attached (Fig. 2).

Then, the clutch pawl 7 is disengaged from the recess 4a of the pulley 4 by an arbitrary change of the clutch pawl operating cam 12a by the operation of the switching knob 12b, and the clutch is switched.

Incidentally, indexing portions 9d and 9d 'for regulating the switching position of the clutch switching plate 12 are provided on the inner peripheral portion of the handwheel 9.
The clutch switching plate 12 is provided with an indexing notch 12c which is integrally formed and which selectively engages with the indexing portions 9d and 9d '(FIG. 2).

Thus, the switching knob 12b can be operated from the outside through the window hole of the handwheel, and now, this is shown in FIG.
The clutch pawl actuating cam 12 is rotated from the solid line position (when the clutch is ON) shown in the figure) to the position shown by the dotted line.
a rotates. Then, the indexing notch 12c of the clutch switching plate 12 moves from the indexing portion 9d 'of the handwheel 9 to 9d. Along with this, the clutch pawl operating cam 12
By rotating a, the clutch claw 7 is brought into the disengaged state as shown in FIG. 7 from the engaged state with the recess 4a shown in FIG. As a result, the relationship between the main shaft 2 and the pulley 4 is changed from engagement to disengagement. On the contrary, if the switching knob 12b is moved from the dotted line in FIG. 4 to the solid line position, the original engagement state is restored.

[Effect of device]

(1) The clutch can be turned on and off in one operation, has excellent operability, and operates quickly.

(2) When interlocking with the spindle, the clutch engages in a short time and immediately enters the work, which contributes to the improvement of the sewing efficiency.

(3) The structure is simple, and it can be constructed compactly without changing the part of the member exposed from the machine frame, and the cost can be covered.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of the assembly of the device of the present invention, and FIG.
FIG. 3 is a sectional view illustrating a clutch engagement, FIG. 5 and FIG. 6 are device component explanatory views, and FIG.
FIG. 7 is a sectional view for explaining the clutch disengagement, and FIG. 8 is an explanatory diagram for the prior art. 1 ... machine frame, 2 ... upper shaft, 4 ... pulley, 7 ... clutch pawl, 9 ... handwheel, 12 ... clutch switching plate, 12a ... clutch pawl operating cam, 12b ... switching knob, 12c ... Indexing notch.

Claims (1)

[Scope of utility model registration request] 1. A clutch having a switching knob portion and an actuating cam portion is brought into contact with a handwheel having a clutch claw that is biased in one direction, and a pulley having a recessed portion that is loosely attached to an upper shaft. A sewing machine clutch device with a switching plate rotatably mounted.