JPH0479985A - Cloth feed mechanism of sewing machine - Google Patents

Abstract

PURPOSE:To reduce the difference in feed per stroke between forward feed and backward feed so as to prevent the shape of a pattern from being broken by providing a feed bar vertically driving mechanism and an oscillation range adjusting means which shifts the oscillation range of an oscillating arm at backward feed relative to that of the arm at forward feed. CONSTITUTION:A cloth feed mechanism is provided with a longitudinally driving mechanism for putting a feed bar D in motion in the longitudinal direction of the feed bar and a vertically driving mechanism 3 for putting the feed bar D in motion in the vertical direction, the feed bar D having a feed dog H fixed thereto. Feed pitch is varied by varying the meshing range of a driven gear 13A with a driving gear 11A, i.e. the oscillation range of an oscillating lever 13. Therefore dispersion in the accuracy of the angle of rotation of a pulse motor 11 and that of parts machining and parts assembly etc. and the difference in feed pitch between forward feed and backward feed caused by the effect of load inertia etc. can both be cancelled out by the difference in feed pitch due to adjustment of a regulating volume 62.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cloth feeding mechanism of a sewing machine, and more specifically, a cloth feeding motor that is different from the drive motor that drives the main shaft moves the workpiece cloth forward and backward. This invention relates to a fabric feeding mechanism of a sewing machine that moves the fabric backward.

[Prior Art] Conventionally, a cloth feeding mechanism has been known in which a cloth feeding motor provided separately from a main shaft drive motor is driven to transport a workpiece cloth forward and backward. This mechanism includes a front-rear drive mechanism that moves a feed table on which feed teeth are formed for transferring the work cloth in the front-rear direction, and a vertical drive mechanism that moves the feed table in the vertical direction. is the fifth
As shown in the figure (schematic view of the inside side of the sewing machine bed), the cloth feed motor (pulse motor) Pl rotates forward and backward at a predetermined angle.
and a swinging arm P5 which is provided with a driven gear P3 that meshes with the drive gear P2 of the cloth feed motor P1 and is swingable in the direction of arrow a about a support shaft P4, and a swinging arm P5 provided on the free end side of the swinging arm P5. A connecting shaft P6, and a horizontal feed arm P8 rotatably supported by the connecting shaft P6 and slidably supported on the free end side or on the horizontal support surface P7.
It consists of.

A guide shaft P9 is vertically provided on both the upper and lower sides of the horizontal feed arm P8, and this guide shaft P9 is connected to the feed base P]
0 (a feed dog pH is formed at the top) so that it can move up and down. Therefore, when the swinging arm P5 swings around the support shaft P4 due to the forward and reverse rotation of the cloth feed motor P by a predetermined angle, the horizontal feed arm P8 supported by the connection shaft P6 moves in the direction indicated by the arrow (front-back direction). The feed bar PIO moves to the guide shaft P9.
is driven in the front-back direction via the

On the other hand, the vertical drive mechanism applies motion in the direction of arrow C to the feed table PIO by rotation of an eccentric cam P12 that rotates in synchronization with the main shaft (not shown), and moves the feed table PIO to the guide shaft P9.
Move up and down along.

By applying a combination of such vertical and two forward and backward movements to the feed table PIO, the work cloth is transferred.

[Problems to be Solved by the Invention] However, due to variations in the rotational angle accuracy of the cloth feed motor, mechanical parts machining accuracy, assembly accuracy, etc., and the influence of load inertia, the workpiece cloth cannot be adjusted between forward feed and backward feed (back feed). Therefore, especially when sewing large patterns that require a large number of counts, the pattern shape may be distorted and the desired pattern cannot be sewn. The purpose is to solve the problem and reduce the difference in feed amount between forward feed and backward feed.

[Means for solving the problem] The fabric feeding mechanism of the sewing machine of the present invention advances the workpiece fabric in synchronization with the rotation of the main shaft of the sewing machine by a fabric feeding motor that is different from the drive motor that drives the main shaft. A cloth feeding mechanism for a sewing machine that feeds forward and backward feeds, comprising: a swinging arm that swings due to the forward and reverse rotation of the cloth feed motor at a predetermined angle and has a connecting shaft on its free end side; and the swinging arm. a horizontal feed arm that is rotatably supported on a connecting shaft and has a supported portion extending from the supported position; and 5. a feed arm support portion that supports the support portion so as to be slidable in the front-rear direction; a feed stand that is supported by the horizontal feed arm so as to be movable up and down and is provided with feed teeth for transferring the work cloth; A feed table vertical drive mechanism that moves the feed table vertically in synchronization with the rotation of the main shaft of the sewing machine, and a swing area in which the swing arm swings in forward feed, and a swing area in reverse feed. The gist of the present invention is to include a swing area adjusting means for relatively shifting the swing area.

[Function] The cloth feed mechanism of the sewing machine of the present invention having the above configuration (the swing arm swings around the support shaft by forward and reverse rotation of the cloth feed motor at a predetermined angle, and the connecting shaft is rotated around the support shaft). The horizontal feed arm is rotatably supported by this connecting shaft, and the supported part extending from the supporting position slides on the feed arm support part. As the connecting shaft moves back and forth, the supported part moves while sliding on the surface of the feeding arm supporting part.For this reason, the supporting part is supported by the connecting shaft and the feeding arm supporting part. The horizontal feed arm tilts depending on the position of the connecting shaft, that is, the swinging position of the swinging arm.

The feed table on which the feed teeth are formed is supported by the horizontal feed arm so as to be movable up and down, and is moved up and down by the feed table up-and-down drive mechanism, and also moves back and forth by transmitting the longitudinal movement of the horizontal feed arm. Therefore, the feed table (upper horizontal feeder) is inclined in accordance with the inclination of the horizontal feed arm. That is, the vertical movement locus of the feed table is inclined in accordance with the swinging position of the swing arm.

If the swing area in which the swing arm swings is the same for forward feed and backward feed, the vertical movement locus of this feed base will also be the same, so theoretically the feed amount for both will be the same. but,
Even in this case, there may be a difference in the feed amount due to machine differences in the drive system. Therefore, by using the swing area adjusting means to relatively shift the swing area for backward feeding with respect to the swing area for forward feeding, the vertical movement trajectory of the feed base in both cases is relatively shifted. In this case, since the vertical movement trajectories of the two are not parallel, a difference occurs in the feed amount.

Therefore, the difference in feed amount due to machine differences in the drive system, etc. (the difference in feed amount caused by the front swing area adjustment means) is offset.

[Embodiment] An embodiment of the cloth feeding mechanism of the sewing machine of the present invention will be described below.

As shown in the perspective view of FIG. 1, the cloth feeding mechanism of the sewing machine of the embodiment includes a front-rear drive mechanism that moves the feed table to which the feed dog H is fixed in the front and rear directions, and a back-and-forth drive mechanism that moves the feed table in the vertical direction. It is provided with a vertical drive mechanism 3 that moves. It also includes an electronic control device 5 shown in the block diagram of FIG.

Back and forth drive mechanism 1 (as shown in Figure 1, pulse motor 1), swing lever] 3, support shaft] 5, swing arm] 7, connection shaft] 9, horizontal feed arm 2), feed arm support The rotary hook K is shown by a two-dot chain line in the figure for the convenience of understanding the arrangement of these parts.

Pulse motor] 1 (Y) It is independent from the drive system of the lower shaft S (main shaft drive system) that is linked to the vertical movement of the sewing machine needle, and is synchronized with the lower shaft S by the electronic control device 5 (Fig. 2), which will be described later. A drive gear]]A is fixed to the output shaft.A light-shielding plate 11B is attached to the drive gear]1A.A photointerrupter 25 is also installed at a position where the light-shielding plate 11B passes. be done.

Swing lever] 3 is a plate material having two levers bent in an abbreviated shape. A support shaft] 5 is inserted through the bent portion, and swings thereby, so that the bar 13 is swingably supported by the support shaft] 5. At the tip of the lever extending toward the front (diagonally forward right in the drawing) is a driven gear 13A that meshes with the drive gear 1A.
can be installed. The center of the pitch circle of the driven gear 13A is
Support axis] coincides with the axis of 5. In the embodiment, the driven gear 13A is made of a resin product and is assembled so as to tightly mesh with the drive gear 11A. Due to this tight assembly, the teeth of the driven gear 13A are plastically deformed to match the shape of the teeth of the drive gear A]. As a result, a gear transmission mechanism with extremely low backlash is realized.

On the other hand, the side surface of the swinging arm 17 is fixed to a lever extending upward from the bent portion.

Swing arm] 7 (It is a substantially H-shaped member. Bearing portions 17A are formed at the lower part of the vertical shaft on both sides of the swing arm).
The support shaft 15 is inserted. The swinging arm] 7 (mountain) swings in this manner and is supported by the support shaft integrally with the bar 13 so as to be swingable.

In addition, both ends of the support shaft 15 are connected to the support shafts 15A and 15B.
It is suspended above a base (not shown) with a slight gap.

On the other hand, bearing portions 17B are formed on each of the upper portions of the vertical axis on both sides of the swing arm]7. A rack (connection shaft) 9 is passed between each bearing portion 17B.

The horizontal feed arm 21 supported by the connecting shaft 9 is a thick plate material having a substantially triangular shape. A roller 2]A (supported part) is provided on the side surface of the front end corresponding to the vertex of the triangle. Bearings 21B and 21C are provided on both sides of the rear end corresponding to the base of the triangle. The connecting shaft 19 passes through the bearing portion 21B. A penetrating connecting shaft] 9 is inserted halfway into the bearing portion 21C.

In this way, the horizontal feed arm 2] is rotatably supported by the connection shaft 9.

Further, a tension spring 27 is tensioned between the lower frame F and the side surface of the horizontal feed arm 2. The tension spring 27 biases the horizontal feed arm 2 downward.
A is always placed on the surface 23A of the feed arm support section 23, which will be described later.
bring them close together.

Further, a guide rod 29 is fixed to the rear bearing portion 21C in a state that it passes through the bearing portion 21C. The axis of the guide rod 29,
It intersects perpendicularly with the plate surface of the horizontal feed arm 2]. The upper part of the guide rod 29 penetrates the feed bar body,
The portion that protrudes from the lower part penetrates into the guide portion D] extending below the feed platform. That is, the feed base is the guide rod 29
is supported on the plate surface of the horizontal feed arm 21 so as to be movable in the vertical direction.

The feed arm support portion 23 is screwed to the frame F. The surface 23A on which the roller 21A slides is formed as a horizontal surface in the front-rear direction. The above-mentioned horizontal feed arm 2] is rotatably supported by the connecting shaft 9, and this surface 23
The rack is slidably supported by A and is passed approximately horizontally.

The operation of the above-mentioned longitudinal drive mechanism will be briefly explained.

As shown in FIG. 1, when the pulse motor]] rotates forward and backward, and its driving gear]1A sends the driven gear 13A in the vertical direction, the swinging lever 13 is rotated about the support shaft 15. oscillate. Then, the swinging arm ]7, which swings and is integrally fixed to the bar 13, similarly swings about the support shaft]5. This swinging of the swinging arm 17 causes the connecting shaft 19 to reciprocate in the front-rear direction. The horizontal feed arm 2, which is suspended between the connection shaft 19 and the feed arm support portion 23, reciprocates in the front and back direction along the connection shaft 19. And the rear guide rod 2
9, the feed bar is pulled in the front-rear direction, and the feed dog H is moved in the front-rear direction.

Next, the vertical drive mechanism 3 will be explained.

As shown in FIG. 1, the vertical drive mechanism 3 includes a lower shaft S, an eccentric cam 3], a vertical movement lever 33, and the like.

The lower shaft S has a timing belt attached to pulley S1,
It is rotated in synchronization with an upper shaft (not shown) for vertical movement of the sewing machine needle.

The eccentric cam 3] is a cam provided eccentrically on the lower shaft S. The amount of eccentricity (the amount of eccentricity is determined according to the vertical stroke of the feed dog H).

The vertically movable lever 33 has its front end swingably supported by the rod 33A, and its lower abdominal surface abuts against the eccentric cam 3.

A roller 35 is rotatably supported on the side surface of the rear end of the vertically movable lever 33. The roller 35 has a lower surface (
Two supporting surfaces 37 are in sliding contact.

On the other hand, a compression spring 39 is disposed between the guide portion D of the feed platform and the horizontal feed arm 21, and urges the feed platform downward. With the above configuration, the support surface 37 is
The vertically moving lever 33 is always in close contact with the eccentric cam 3]. Therefore, the roller 35 accurately moves up and down in accordance with the shape of the eccentric cam 31, and the feed bar also moves up and down in accordance with the shape of the eccentric cam 31.

Next, regarding the electronic control device 5 that controls the above-mentioned mechanism,
This will be explained based on FIG. The electronic control device 5 is a well-known C
PU51. ROM53. It is an arithmetic and logic operation circuit that includes a RAM 55, input/output interfaces 57, 59, and the like. The input interface 57 includes an operation switch 61 for power supply, etc.
The photointerrupter 25 and the adjustment volume 62 are connected.

This adjustment volume 62 is for changing backward feed start position data, which will be described later, and is installed in the sewing machine bed (path shown). The output interface 59 has a lower shaft S.
A drive circuit 65 for a main shaft motor 63 that rotates the main shaft S is connected. Also, the pulse motor of the longitudinal drive mechanism 1]]
A drive circuit 67 is connected thereto.

Next, the cloth feeding process executed by the electronic control device 5 will be explained. FIG. 3 is a flowchart showing the cloth feed control routine.

This routine is executed when the start of sewing is instructed by a predetermined operation, but prior to this process, the origin of the phase of the drive gear IIA of the pulse motor 1 is determined by using the on/off signal of the photointerrupter 25. The pattern data set by the operator is also selected.

First, cloth feed data is read (S100).

This feed data (song) is feed pitch data that indicates the transfer amount (feed pitch) of the work cloth that is set for each needle.

Next, it is determined whether this feed data is for backward feed (
S 110).

If “NO”, that is, forward feed, step]40
Then, the pulse motor 1 is rotated forward and backward by the rotation angle determined from the read cloth feed data, that is, by the rotation angle corresponding to obtaining the feed pitch specified by the data. In this case, the first
The drive gear IIA is rotated from the upper end M1 of the meshing region indicated by the arrow M in the figure. Drive gear] at the upper end M of the meshing area of arrow M
] To position A, the forward feed start position data set in the RAM 55 of the electronic control device 5 is used. The driven gear 13A is sent upward by an amount corresponding to the rotation angle of the drive gear ]]A, and then sent downward by the reverse rotation of the drive gear IIA. Therefore, the swing lever] 3 moves back,
Connection shaft 19. Movement in the forward and backward direction is applied to the feed dog H via the horizontal feed arm 21 and the like. And pulse motor]1
Since the rotation timing of is controlled in synchronization with the rotation of the lower shaft S, in combination with the vertical movement by the vertical drive mechanism 3, the feed dog H moves along the trajectory shown by the arrow 1 in FIG. .

On the other hand, if the determination in step]10 is rYESJ, that is, in the case of backward movement, the process moves to step 120, and the set value of the adjustment volume 62 is read. Then, based on this set value, the backward feed start position data set in the RAM 55 of the electronic control device 5 is changed (3130). When the setting value of the adjustment volume 62 is O, the drive gear 1A is rotated from the lower end U of the meshing area indicated by the arrow U in FIG.
If the set value is not 0, the backward feed start position data is changed so that the rotation start position is shifted from the lower end U1 by an angle corresponding to the set value.

When the processing in step]30 is completed, the process moves to step 140, and the pulse motor 11 is rotated in forward and reverse directions based on the changed backward feed start position data and feed pitch data. At this time, driven gear 13AI & driving gear 11A
The tag is then sent upward by the reverse rotation of the drive gear 11A, so that the swing lever 13 moves back. Therefore, the feed dog H is given a longitudinal movement, and in combination with the vertical movement by the vertical drive mechanism 3, the feed dog H moves in a trajectory shown by arrow 2 in FIG. 1.

That is, the processing in steps 120 and 130 is performed in accordance with the set value of the adjustment volume 62 to
The meshing area of 3A is changed, and the trajectory of the feed dog H is changed in 2. Therefore, the trajectory of the feed dog H in forward feed is 1
The locus of the feed dog H for backward feeding can be shifted by 2 within a possible range using the adjustment volume 62.

When the process of step 140 is completed, it is determined whether or not the cloth feeding process is finished (5150), and if end data is included in the cloth feeding data read in step 100, this routine is ended. On the other hand, if it is not the end (sing again,
Returning to step 100, the process described above is repeated.

The cloth feeding process has been described above, and now the influence of the feeding pitch that occurs when the locus of the feeding dog H is changed will be explained with reference to FIG. 4.

FIG. 4 is an explanatory diagram showing the locus (trajectory seen from the side) of the feed dog H that moves by the longitudinal drive mechanism and the vertical drive mechanism described above.

The meshing area of the driving gear IIA in the driven gear 13A is
Figure (A) shows the trajectory of the feed dog H when the driven gear 13A is set at approximately the center position (hereinafter referred to as the center area).
FIG. 2B shows the trajectory of the feed dog H when the driven gear 13A is set at the upper end and lower end sides (hereinafter referred to as the upper end region and the lower end region, respectively). Note that the rotation angle of the pulse motor 11 in each of the above cases, that is, the swing arm 17
The swing angle θ is the same, and explanation will be given by taking backward feeding as an example.

When the swinging arm 17 swings about the support shaft] 5, the connecting shaft 19
, it reciprocates in the front-back direction while drawing an arc-shaped locus centered on the support shaft 15 . Horizontal feed arm 2] (Since it is rotatably directed by the upper connecting shaft 19, the movement of this connecting shaft 19 causes it to move back and forth while tilting its plate surface. Therefore, it is perpendicular to the plate surface of the horizontal feed arm 21. The guide rod 29 (
It is inclined with respect to the vertical line due to the inclination of the horizontal feed arm 21,
The locus of the feed carriage that is sent vertically along the guide rod 29 is inclined with respect to the vertical line.

When the swinging arm 17 is swung in the central area (Fig. 4 (A)
), the guide rod 29 becomes almost parallel when the feed bar is raised and lowered, so the feed tooth H (moves by tracing a parallelogram trajectory K11l). The feed pitch is dlo.

When the swinging arm 17 is swung in the upper end area, as shown in FIG.
) As shown on the right side, the guide rod 29 tilts to the left in the drawing with respect to the vertical line when the feed bar is raised and lowered, but this tilt is larger when it is lowered, so
Feed dog) -111 Moves by drawing 20 on a downward trapezoidal locus. Therefore, the feed pitch d20[i is smaller than the feed pitch dlO in the central region.

When the swinging arm 17 is swung in the lower end area (as shown in Fig. 4 (B)
) As shown on the left side, the guide rod 29 tilts to the left in the drawing with respect to the vertical line when the feed bar is raised and lowered, but this tilt is larger when it is raised, so
The feed dog H moves in a trapezoidal locus 30 that opens upward. Therefore, the feed pitch d30 is larger than the feed pitch dlo in the central region.

As explained above, the feed pitch is changed by changing the engagement area of the drive gear IIA in the driven gear 13A, that is, by changing the swing area of the swing lever 3. For this reason, the rotation angle accuracy of the pulse motor]
The difference in feed pitch between forward feed and backward feed due to variations in parts processing accuracy, assembly accuracy, etc., and the influence of load inertia, etc. can be offset by the difference in feed pitch by adjusting the adjustment volume 62. Therefore, before shipping the sewing machine,
By adjusting with the adjustment volume 62 so that the feed pitch of backward feed and the feed pitch of forward feed are equal, the backward feed start position can be changed during sewing by the above-mentioned cloth feed process, and accurate cloth feed can be carried out. be done.

As a result, it becomes possible to sew the selected pattern into the correct shape. This is particularly effective when sewing large patterns in which many differences in feed pitches are accumulated. In addition, if there is a difference in the feed pitch due to changes over time, etc., by adjusting the adjustment volume 62,
Accurate cloth feeding can be performed again.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way. It goes without saying that the present invention can be implemented in various ways without departing from the gist of the present invention.

Effects of K River As detailed above, IQ is achieved by the cloth feeding mechanism of the sewing machine of the present invention. Since the adjustment is made to shift the feed rate, the difference in feed amount caused by machine differences in the drive system, etc. can be offset by the difference in feed amount caused by the inclination of the vertical movement locus of the feed table.

As a result, an extremely excellent effect is achieved in that the difference in the amount of feed between forward feed and backward feed is reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the cloth feeding mechanism of the sewing machine of the present invention, and FIG. 2 is a block diagram of the electronic control device.
FIG. 4 is an explanatory diagram illustrating the operation of the cloth feeding mechanism of the sewing machine, and FIG. 5 is an explanatory diagram illustrating the conventional mechanism. ] ... Front-rear drive mechanism 5 ... Electronic control device 3 ... Swing lever 7 ... Swing shaft 1 ... Horizontal feed arm 3 ... Send arm support section 2 ... Adjustment volume D ... Feeding table S ... Lower shaft 3 ... Vertical drive mechanism] ... Pulse motor 5 ... Support shaft 9 ... Connection shaft 1A ... Roller 3A ... Arc-shaped surface H ...Feed dog

Claims (1)

[Scope of Claims] 1. A fabric feeding mechanism for a sewing machine that feeds work cloth forward and backward in synchronization with the rotation of a main shaft of the sewing machine by a fabric feeding motor that is different from a drive motor that drives the main shaft, comprising: A swinging arm that is swung by the forward and reverse rotation of the cloth feed motor at a predetermined angle and has a connecting shaft on its free end side, and a swinging arm that is rotatably supported by the connecting shaft of the swinging arm and is supported by the swinging arm. a horizontal feeding arm having a supported portion extending from the horizontal feeding arm; and a feeding arm support portion provided opposite to the supported portion of the horizontal feeding arm and slidably supporting the supported portion in the front-back direction. and a feed table which is vertically movably supported by the horizontal feed arm and has feed teeth for transferring the work cloth, and which moves the feed table in the vertical direction in synchronization with the rotation of the sewing machine main shaft. and a swinging area adjusting means for shifting the swinging area in backward feeding relative to the swinging area in which the swinging arm swings in forward feeding. Cloth feed mechanism of sewing machine.