FR2653791A1 - DEVICE FOR RELEASING THE HOOK OF A SEWING MACHINE. - Google Patents

Abstract

A hook disengaging device on a sewing machine, with a hook shaft performing a pivoting movement and a translational movement, at least one hook and a needle, a flange attached to the hook shaft and a cooperating hook holder with the flange, which support can pivot from a sewing position to a threading position, characterized in that an intermediate transmission (28), having a stop position (33), is associated with the hook support ( 36) and to the flange (23) and is designed so that its transmission movements are approximately parallel to the pivot plane of the hook (40).

Description

The present invention relates to a hook release device on

  a sewing machine, with a hook shaft performing a pivoting movement and a translational movement, at least one hook and one needle, a flange fixed on the hook shaft and a hook support cooperating with the flange, which support can rotate from a sewing position to a threading position. A device of this type is known from US Pat. No. 4,671,195. This patent describes a hook shaft performing a pivoting movement and a translational movement as well as a fork-shaped part which is fixed on a hook support and which cooperates with a disc (flange) fixed on the hook shaft and having stops, so that the pivoting movement of the hook support is limited to the threading position and to the sewing position. To fix the hook support in one of these two positions, this device comprises a manually operated lever making it possible to fix the hook support on the hook shaft, at the

  by means of a screw, or detach it from the hook shaft.

  The pivoting movements of the lever take place in a plane parallel to the hook shaft. If this device

  is correctly ordered, its function is certainly total-

  filled, but if the lever is tightened incorrectly, there is a risk that the hook support will come off the hook shaft. After operating the sewing machine, this can lead to an adjustment or even damage to the device, because the fork-shaped part uncontrollably hits the stops of the

disk.

  The invention therefore proposes to configure a

  hook release device to allow

  reliably lock the hook support in the sewing position.

  This goal is achieved with a device for

  hook clutch of a sewing machine of the aforementioned type, in that an intermediate transmission, having a stop position, is associated with the hook support and the flange and is designed so that its transmission movements are at roughly parallel to the pivot plane of the hook. Due to the use of this intermediate transmission, whose stop position corresponds to the sewing position of the hook support and therefore also of the hook, there is this great advantage that even when the hook is not engaged in its sewing position, the

  hook declutching device cannot be damaged

  magé. Because of the inertia of the moving parts, the hook declutching device presses the hook support, after actuation of the sewing machine, in its sewing position, due to the pivoting of

the hook shaft.

  In another variant of the declutching device

  hook, it is provided that the hook support is pivotally mounted on the flange eccentrically to the hook shaft, which flange carries a pawl bearing on a surface against a counter surface in the stop position of the intermediate transmission and which positions the hook, in position

sewing.

  Since, according to another variant, a spring is associated with the pawl, manual actuation of the hook support is thereby facilitated. Thanks to the stopper of the hook support which limits the pivoting of the latter towards the needle, a threading position is defined which

facilitates the operation.

  According to a particularly simple variant of the intermediate transmission, the hook support is pivotally mounted on the flange concentrically with the hook axis and a hook support arm and a flange arm connect the transmission support

hook to the strap.

  In a variant of the invention, the flange has a stop which limits the pivoting of the hook support and thus defines the stop position of the mechanism

with swing arm.

  Various other features of the invention

  moreover emerge from the detailed description which

follows.

  Embodiments of the subject matter of the in-

  are shown, by way of non-limiting examples.

tifs, to the accompanying drawings.

  Fig. 1 is a front view of part of a sewing machine comprising a clutch release device

hook in sewing position.

  Fig. 2 is a front view of part of a sewing machine comprising a clutch release device

hook in threading position.

  Fig. 3 is a side view of part of a sewing machine comprising a clutch release device

hook in sewing position.

  Fig. 4 is a perspective view of a

  hook release device.

  Fig. 5 is a front view of a part of a sewing machine comprising another device for

  hook release in sewing position.

  Fig. 6 is a front view of a part of a sewing machine comprising another device for

  hook release in threading position.

  Fig. 1 shows a part of a chain stitch sewing machine 10 comprising a hook release device. The sewing machine 10 has a lower part 12, a working surface 14 and a needle plate 15. At least one needle 16 is fixed, by a screw 17, in a needle head 18 which is arranged at the end of a needle bar 19

rising and falling.

  A cover plate 21 which is fixed by three screws 22 on the lower part 12 is disposed behind a flange 23 which has a stop 24. An intermediate support 25, fixed in an adjustable manner on the flange 23, carries a pawl 27 pivoting around 'a pivot 26 and which is part of an intermediate transmission 28. The pawl 27 bears, by a surface 29, against a pivot 32 having a counter surface 31, in a stopped position 33. A guide plate 34 is fixed by a nut 35, on the intermediate support 25 and guides a hook support 36 which is pivotally mounted, around a screw 38, on the flange 23, eccentrically with respect to a hook shaft 37. The flange 23 is fixed by a screw 39 on the hook shaft 37. At the upper end of the hook support 36 is fixed a hook, by means of a screw 41; at the lower end, the pivot 32 is placed, which with the surface 29 of the pawl 27,

  defines the stop position 33 of the inter-

  medial 28 which corresponds to the sewing position of the

  hook 40. An outline 42, drawn in dotted lines, represents

  feel the pawl 27 in the deflected position which allows the hook support 36 to be pivoted in its position

  threading, shown in fig. 2.

  The hook support 36 bears in its threading position, by a concave surface 43, against the intermediate support 25 which carries a spring 44 which is applied, elastically, against the pawl 27, by its free end. The pawl 27 bears on its side, by a surface 45 also concave, against the

  counter surface 31 of the pivot 32. The intermediate transmission

  diary 28 includes intermediate support 25, pivot

  26, the pawl 27, the pivot 32 and the spring 44.

  Fig. 3 shows a known hook drive device 46 which gives the hook shaft 37 and therefore also the flange 23, the translational and pivoting movement. The intermediate support 25 by which the fixing is carried out with the flange 23, eccentric with respect to the pivot 26, is fixed to the flange 23, by a nut 47. The eccentricity on the intermediate support 25 allows an adjustment of the surface 29 of the ratchet 27, in

  direction of the counter-surface 31 of the pivot 32 (fig. 1).

  A stop 48 of the pivot 32 is applied against the flange 23,

  when the hook 40 is in the sewing position.

  The pivoting of the hook support 36 takes place around a bushing 49 which is tightened with the guide plate 34, against the flange 23, by the screw 38. A known pressing device 51 is placed above the plate

  needle 15 and supports a sewing piece 52.

  The different parts of the inter-

  intermediate 28, arranged between the flange 23 and the support

  hook 36, are shown in perspective in FIG. 4.

  By actuation of the pawl 27, anti-clockwise, and by simultaneous pivoting of the hook support 36 in a clockwise direction, the hook support 36 comes out of its sewing position (fig. 1) to switch to its threading position (fig. 2). The pivoting path of the hook support 36 is limited in this case by the intermediate support 27, the pivoting path of the pawl 27 by the stop 24. After releasing the pawl 27, it returns to the position shown.

  fig. 2, as a result of the action of the spring.

  The engagement of the hook support 36 in its

  sewing position is done manually by pivoting

  the hook support 36 counterclockwise until the counter surface 31 of the pivot 32 comes into contact with the surface 29 and

  that the pivot 48 is applied against the flange 23. In conti-

  by pressing down the pawl 27 downwards, transmitting it

  intermediate sion 28 is fixed in its stop position 33, since the surface 29 prevents the return of the hook lever 36. The engagement of the intermediate transmission 28 in its stop position 33 is also effected by desired or unintended actuation sewing machine, which prevents damage to the clutch release device

hook.

  Figs. 5 and 6 show another embodiment of the subject of the invention. The parts which correspond to the device described above, bear

the same references.

  A flange 23A is fixed by the screw 39 on the shaft

  hook 37 and carries an intermediate transmission 28A.

  The flange 23A comprises a hollow rod 61, placed concentric

  trunk to the hook shaft 37, hollow rod on which a hook support 36A is mounted on the flange 23A, concentrically to the hook axis 37. A hook support arm 62 is fixed, by a screw 63, on the hook support 36A, so as to be able to pivot and is connected, by an articulation 64, to a flange arm, by shape correspondence, this flange arm being articulated on its side on a pivot 66 of the flange 23A. The intermediate transmission 28A contains the hook support arm 62, the screw 63, the articulation 64, the flange arm 65 and the pivot 66. A stop 67, placed

  adjustable on flange 23A, limits the pivot path

  the hook support 36A. With a split adjustment ring 68 which is fixed by a screw 69 on the hollow rod 61, the hook support 36A can be placed axially against the flange 23A. The hook support 36A carries two hooks 40 which cooperate with two

needles 16.

  The disengagement of the hook support 36A from its sewing position (fig. 5) to its threading position (fig. 6) is effected by actuation of the articulation 64, in the clockwise direction. In the threading position, the hook support 36A bears against the articulation 64. The hook support 36A is snapped into its sewing position by pivoting the two arms 62 and 65, in the opposite direction to the needles of a watch, in their stretched position. The hook support 36A then pivots towards the stop 67. Here again, the hooking of the hook support 36A in its stop position 33A can be done manually or by actuation of the sewing machine. Given the inertia of the parts, the intermediate transmission 28A

  is in this case pressed into its stop position 33A.

Claims (6)

  1. Hook declutching device on a sewing machine, with a hook shaft performing a pivoting movement and a translational movement, at least one hook and one needle, a flange fixed on the hook shaft and a support hook cooperating with the flange, which support can pivot from a sewing position; a threading position, characterized in that an intermediate transmission (28, 28A), having a stop position (33, 33A), is associated with the hook support (36, 36A) and the flange (23, 23A) and is designed so that its transmission displacements are at   roughly parallel to the pivot plane of the hook (40).   2. Hook declutching device according to claim 1, characterized in that the hook support (36) is pivotally mounted on the flange (23) eccentrically relative to the hook shaft (37), which flange carries a pawl (27) bearing by a surface (29) against a counter surface (31) in the stopped position (33) of the intermediate transmission (28) and which positions the hook (40), in the sewing position. 3. Hook declutching device according to claim 2, characterized in that a spring (44) is associated with the pawl (27).   4. Hook declutching device according to claim 2, characterized in that the support of   hook (36) has a stop (48) which limits the movement   pivot of the hook support (36), towards tion of the needle (16).   5. Hook declutching device according to claim 1, characterized in that the hook support (36A) is pivotally mounted on the flange (23A) concentric with the hook axis (37) and in that a hook support arm (62) and a flange arm (65) connect the hook support (36A) to the transmission the flange (23A).   6. hook release device according to claim 5, characterized in that the flange (23A) has a stop (67) which limits the movement of   pivoting of the hook support (36A).