WO2024029433A1

WO2024029433A1 - Sewing machine

Info

Publication number: WO2024029433A1
Application number: PCT/JP2023/027487
Authority: WO
Inventors: 隆水▲崎▼
Original assignee: ヤマトミシン製造株式会社
Priority date: 2022-08-05
Filing date: 2023-07-27
Publication date: 2024-02-08

Abstract

The present invention comprises a needle that holds a needle thread and moves up and down through a throat plate, a looper that holds a looper thread and reciprocates in a space below the throat plate to entangle the looper thread with the needle thread, a retainer that reciprocates in the space below the throat plate and captures the looper thread, and a retainer movement mechanism that changes the movement state of the retainer while transmitting driving force from a drive source to the retainer. For a given period of time during which the retainer is within a given range of positions in the space below the throat plate, the retainer movement mechanism performs the reciprocating motion at a lower speed than that used before and after the given period of time, thereby continuing the state in which the looper yarn is captured.

Description

sewing machine

Cross-reference of related applications

This application claims priority based on Japanese Patent Application No. 2022-125579 and Japanese Patent Application No. 2022-188995, which are incorporated into the description of the present application by reference.

The present invention relates to a sewing machine that can form a circular seam with a spread looper thread without using a retainer needle that penetrates the fabric.

Sewing machines that can form a circular seam with a spread looper thread have long existed. For example, there is a sewing machine described in Japanese Patent Application Publication No. 2001-314681 (Patent Document 1). The sewing machine described in Patent Document 1 is provided with a retainer that moves below the throat plate without penetrating the throat plate, so that the retainer holds the looper thread and makes a hole through the fabric. It is configured so that a loop-shaped seam with a widened looper thread can be formed at the double loop portion without using a retainer needle that would otherwise be damaged. According to the illustrated content of Patent Document 1, the seam shown in FIG. 3 of Patent Document 1 corresponds to the seam shown in FIG. 4 of Patent Document 1 (viewed from the back side of the fabric) (but , holes due to the penetration of the retainer needle into the fabric do not occur as shown in FIG. 3).

Japanese Patent Application Publication No. 2001-314681

In the sewing machine described in Patent Document 1, the retainer is configured to reciprocate within a predetermined range along an arcuate trajectory in response to the driving force of a main shaft provided inside (see FIG. 2 of Patent Document 1). . Since this reciprocating motion is a simple reciprocating motion, the moving speed of the retainer momentarily becomes 0 as the moving direction is changed when turning back in the reciprocating motion, but the moving speed of the retainer during forward and backward motion is changes along a sine curve with a constant shape in relation to time. For this reason, for example, in order to form an annular seam with the looper thread having the desired spread, the retainer needs to continuously hold the looper thread (time from capturing the looper thread to releasing it). It is necessary to increase the reciprocating stroke of the retainer (reciprocating range ) needs to be set large. This is because the retainer moves to the turning point after capturing the looper thread, and releases the looper thread after the direction of movement is reversed. However, for example, in small sewing machines, there is a limit to increasing the internal volume of the cylinder, so even if the retainer is intended to hold the looper thread for the length of time required to create the desired stitch, the retainer cannot be installed inside the cylinder due to space constraints. There are cases where it is impossible to increase the reciprocating stroke because the reciprocating range cannot be accommodated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sewing machine in which the retainer can hold the looper thread for a longer period of time without having to set a large reciprocating stroke of the retainer, and can realize a seam in which the looper thread has a desired spread. shall be.

The present invention includes a needle that holds a needle thread and moves up and down through a throat plate, and a needle that holds a looper thread and moves back and forth in a space below the throat plate to entangle the looper thread with the needle thread. a looper that reciprocates in a space below the throat plate and captures the looper yarn, and a retainer that changes the state of motion of the retainer while transmitting driving force from a drive source to the retainer. a mechanism, the retainer movement mechanism is configured to perform the reciprocating motion so as to move the retainer at a lower speed than before and after the retainer for a predetermined period of time in a predetermined range of positions in a space below the throat plate. , a sewing machine in which the retainer continues to capture the looper thread.

The certain range related to the low-speed movement of the retainer by the retainer movement mechanism is a turn-around position where the retainer reverses from a forward direction to a backward direction, and a vicinity of the turn-back position, and It can be a range between two positions separated in the direction.

Further, the retainer movement mechanism may cause the retainer to once retreat from the folded position within the certain range, then advance to the folded position again, and then further retreat.

The retainer movement mechanism includes a link mechanism in which two link units are combined, and the link mechanism is connected to the input side connection point of each of the link units and the output side by inputting reciprocating motion. The straight lines connecting the connection points are configured to repeatedly change in a part or all of the range between a straight line state and a bent state, and at least the link mechanism is in the bent state. The retainer may be configured to continue to capture the looper yarn while the looper yarn disappears, the change turns around, and the looper yarn starts bending again.

The retainer movement mechanism includes a link mechanism in which two link units are combined, and the link mechanism is connected to the input side connection point of each of the link units and the output side by inputting reciprocating motion. The straight lines connecting the connecting points are configured to repeat a proximal bent state bent in one direction, a straight line state lined up in a straight line, and a distal bent state bent in the other direction, and in contrast to the straight line state, the proximal bent state In the bent state, the bending point between both link units is set closer than in the distal bent state, and at least the link mechanism passes from the straight line state to the proximal bent state and returns to the straight line state. The retainer may be configured to continue to capture the looper thread until the looper thread is released.

The retainer movement mechanism includes an input-side rotation member that is provided on the input side and rotates within a certain range, an output-side rotation member that is provided on the output side and rotates within a certain range, and the input-side rotation member. a displacement transmission mechanism that transmits a displacement from the input side rotation member to the output side rotation member, and the displacement transmission mechanism transmits a tangential component of the rotational displacement of the input side rotation member and a rotation of the output side rotation member. Depending on the angular relationship between the dynamic displacement and the tangential component, the amount of displacement transmitted from the input-side rotation member to the output-side rotation member can be temporarily reduced.

The input-side rotation member has a first input arm and a first output arm extending in different radial directions from the first rotation center, and receives the driving force input from the first input arm. , the first output arm outputs a rotational force about the first rotation center, and the output-side rotation member has a second input arm extending in a different radial direction from the second rotation center, and a second an output arm, and outputs the driving force input from the second input arm from the second output arm as rotational force about the second rotation center;
The displacement transmission mechanism is provided in the first output arm or the second input arm and includes a groove extending parallel to a radial direction passing through the first rotation center or the second rotation center. , a slide member that is provided on the second input arm or the first output arm and moves along the groove.

FIG. 1 is a perspective view showing a sewing machine incorporating a mechanism according to an embodiment of the present invention. FIG. 2 is a perspective view showing an extracted area including the retainer movement mechanism (link mechanism) according to the first embodiment, and shows a state in which the retainer is most advanced (advanced). FIG. 3 is a perspective view showing an extracted area including the link mechanism according to the first embodiment, and shows a state in which the retainer is most retracted (retracted). FIG. 4A is a perspective view of main parts showing the positional relationship between the retainer and the looper of the link mechanism according to the first embodiment, and corresponds to the state shown in FIG. 3. FIG. 4B is a perspective view of main parts showing the positional relationship between the retainer and the looper of the link mechanism according to the first embodiment, and corresponds to the state shown in FIG. 2. FIG. 5 is a perspective view showing the positional relationship of the needle, the looper, and the looper thread (retainer not shown) in the order of operation in the first embodiment. FIG. 6 is a perspective view showing the positional relationship of the needle, looper, needle thread, and looper thread (retainer not shown) in the order of operation in the first embodiment. FIG. 7 is a perspective view showing the positional relationship of the needle, looper, retainer, needle thread, and looper thread in order of operation in the first embodiment. FIG. 8 is a perspective view showing the positional relationship of the needle, looper, retainer, needle thread, and looper thread in the order of operation in the first embodiment. FIG. 9 is a perspective view showing the positional relationship of the needle, looper, retainer, and looper thread (the needle thread is not shown) in the order of operation in the first embodiment. FIG. 10 is a perspective view showing the positional relationship of a needle, a looper, a retainer, and a looper thread (the needle thread is not shown) in the order of operation in the first embodiment. FIG. 11 is a graph showing changes in the advancing state of the retainer in the first embodiment. FIG. 12 is another graph showing changes in the advanced state of the retainer in the first embodiment. FIG. 13 is a perspective view extracting and showing the range including the retainer movement mechanism (link mechanism) according to the second embodiment, and shows when the retainer is in a normal speed state (when the needle is at the top dead center position). show. FIG. 14 is a perspective view showing an extracted area including the link mechanism according to the second embodiment, and shows a case where the retainer is in a low speed state (when the needle is at the bottom dead center position). FIG. 15 is a graph showing changes in the advancing state of the retainer in the second embodiment. FIG. 16 is a perspective view showing an extracted area including the retainer movement mechanism according to the third embodiment. FIG. 17 shows a retainer movement mechanism according to the third embodiment, and is a perspective view when viewed from the opposite side to FIG. 16. FIG. 18 is an exploded perspective view showing a retainer movement mechanism according to the third embodiment. FIG. 19 is an explanatory diagram showing the operation of the retainer movement mechanism according to the third embodiment.

Next, embodiments of the present invention will be explained. The sewing machine 1 of the present embodiment is a sewing machine 1 capable of forming a circular seam in which the looper thread Lb is spread, and is mainly used for forming double chain stitches. It can also be used when forming other seams using Further, the "double chainstitch" includes both single needle double chainstitch and multi-needle double chainstitch. Note that the vertical direction in the following description is the direction in the embodiment.

[First embodiment]
In a sewing machine 1 having a built-in mechanism according to the present embodiment (first embodiment), as shown in FIG. 1, a cylinder 2 that supports the fabric during sewing is cylindrical. Note that a sewing machine 1 incorporating a mechanism according to a second embodiment, which will be described later, has the same external appearance. The fabric is fed along the longitudinal direction of this cylinder 2. In this embodiment, the fabric is fed from the right to the left in FIG. 1 and sewn. A sewing section is provided at the tip of the cylinder 2, where the needle 3 moves up and down to perform sewing. ). A worker (operator) who performs sewing work is located on the right side of the sewing machine 1 in FIG. 1 (in the direction of arrow OP shown in the figure). Here, since the sewing machine 1 of the present embodiment is specialized for sewing fabric into a cylindrical shape, the cylinder 2 is formed to be thinner than, for example, a sewing machine in which the fabric is fed perpendicularly to the longitudinal direction of the cylinder. It should be noted that since the internal space of the cylinder 2 is also small, there is a space restriction on the arrangement of internal parts. Note that the reference numeral "OP" has been added to the figures necessary for explanation, but even in the drawings without the reference numeral, the positional relationships are the same as those in the figures with the reference numeral.

In the sewing machine 1 of this embodiment (the same applies to the second embodiment described later), the main parts involved in forming seams are the needle 3, looper 4, and retainer 5 shown in FIGS. 4A and 4B. The configurations of the needle 3 and looper 4 are the same as known ones. The needle 3 holds the needle thread La (see FIG. 6, etc.) and moves up and down through the needle plate 21. In this embodiment, a plurality of needles 3 are provided (specifically, four needles). Note that in the past, a retainer needle was provided in parallel with a sewing needle, but in this embodiment, there is no retainer needle, and only the sewing needle 3 is provided as a needle that penetrates the fabric.

The looper 4 has the shape shown in FIGS. 5 to 10, for example, and holds the looper thread Lb (see FIG. 5, etc.) and reciprocates in the space below the throat plate 21 in the cylinder 2. As shown in 8, the looper thread Lb is entwined with the needle thread La. As shown in the figure, the looper 4 has a curved shape that is slightly convex upward, and as shown in FIG. ing. The looper 4 of this embodiment reciprocates with respect to the cylinder 2 in a direction (width direction of the cylinder 2) perpendicular to the direction in which the fabric is fed. Therefore, in this embodiment, since the looper thread Lb can be swung left and right with respect to the fabric feeding direction by the looper 4, the seam itself can be formed even if the retainer 5 is not used. Therefore, the retainer 5 described below is not an essential component for forming seams. The retainer 5 of this embodiment holds the looper thread Lb pulled out by the looper 4 when forming a double chainstitch or the like, and as a result, the looper thread Lb realizes a seam with a desired spread. The composition is as follows.

The retainer 5 reciprocates in the space below the throat plate 21 in the cylinder 2 and captures the looper thread Lb held by the looper 4. The retainer 5 in the mechanism according to this embodiment is connected to a link mechanism 6 as a retainer movement mechanism shown in FIGS. 2 and 3, and is reciprocated by converting and transmitting the driving force of a main shaft (not shown). . Unlike conventional retainer needles, this retainer 5 does not penetrate the fabric due to the reciprocating motion. The retainer 5 is formed by bending a plate-shaped body as shown in FIG. The flat base 51 is attached to a retainer support 8 that swings by a link mechanism 6 . In this embodiment, the retainer support 8 is attached so that the fixing hole 511 coincides with the attachment portion 82 of the retainer support 8 . Note that the center of rotation of the retainer 5 coincides with the rotation support portion 81 of the retainer support 8 (the center of rotation related to the rocking). A connecting portion 52 is formed at the upper end of the base portion 51 and bent in the thickness direction, and a tip portion 53 is formed at the tip of the connecting portion 52 and projects perpendicularly to the direction in which the connecting portion 52 extends. The base portion 51, the connecting portion 52, and the tip portion 53 are integrated. The retainer 5 captures the looper thread Lb by hooking the looper thread Lb at the distal end portion 53 (more specifically, the portion of the distal end portion 53 closer to the connecting portion 52). The tip portion 53 of the retainer 5 reciprocates in a direction perpendicular to the reciprocating direction of the looper 4 (a direction along the longitudinal direction of the cylinder 2). Therefore, in the retainer 5, the moving direction of the tip portion 53 on which the looper thread Lb is hooked is orthogonal to the moving direction of the looper 4 (see the moving direction indicated by the arrow in FIG. 7).

The link mechanism 6 changes the state of movement of the retainer 5 while transmitting the driving force from the drive source (motor, not shown) of the sewing machine 1 to the retainer 5. The link mechanism 6 of this embodiment connects a transmission rod 7 that reciprocates in the axial direction (up and down) in response to the driving force of the main shaft and a retainer support 8 that supports the retainer 5. Note that the main shaft rotates, and is converted into reciprocating motion by a conversion mechanism such as an eccentric mechanism interposed between the main shaft and the transmission rod 7. This link mechanism 6 is composed of a first member 61 to a sixth member 66 that are rotatably connected to each other from the base end side to the distal end side of the cylinder 2.

The first member 61 and the third member 63 have different V-shapes, and each end portion of the V-shape rotates around a rotation fulcrum of a folded portion of the V-shape. The first member 61 is connected to the end of the transmission rod 7. The second member 62 and the fourth member 64 to the sixth member 66 are each shaped like an I (straight bar), and both end portions in the longitudinal direction are rotatably connected to other members. The fifth member 65 is a member that extends between the base end and the distal end of the cylinder 2 and is longer than the other members.

What is important in this embodiment is the relationship of driving force transmission between the vertically moving transmission rod 7 and the first to third members 61 to 63 when the retainer 5 captures the looper thread Lb. The first member 61 (the output arm portion 611, which is the part of the V-shape on the opposite side to the transmission rod 7) and the second member 62 as a link unit form an input side connection between the two members 61 (611) and 62. Regarding the relationship between the straight lines connecting the points and the output side connection points, the straight line state in which they are lined up on the same straight line as shown in the connection direction X shown in FIG. corresponds to The bent state of the output arm portion 611 of the first member 61 and the second member 62 and its change can be set in various ways without particular limitation. It appears twice in one cycle of the reciprocating motion of the transmission rod 7, which is the side. In the first linear state, the transmission rod 7 is continuing to descend at that moment. When the transmission rod 7 further descends and reaches the lowest end, the output arm 611 of the first member 61 and the second member 62 change from the state shown in FIG. (or a "V" shape tilted to the right). Note that in the proximal bent state, the bend of the character "<" is slight (the angle is several degrees), and it is difficult to distinguish from the straight state in appearance, so it is not shown. When the transmission rod 7 starts to rise, the angle of the "<" character increases, and after the second straight line state, the output arm 611 of the first member 61 and the second member 62 form the ">" character. (or a "V" shape tilted to the left), and is bent in the connecting direction Y, which is the distal bent state shown in FIG. The transmission rod 7 has now reached its uppermost end. When the transmission rod 7 begins to move downward, the angle of the ">" character increases and returns to the straight line state shown in FIG. 2. This operation is repeated as the transmission rod 7 reciprocates up and down. In this case, the states that result in changes in bending are a proximal bending state and a distal bending state. Note that the bending point between the first member 61 (output arm portion 611) and the second member 62 is set closer in the proximal bent state than in the distal bent state with respect to the straight state.

With regard to the reciprocating movement of the retainer 5, the link mechanism 6 configured to operate in this manner moves the retainer 5 in a certain range of positions in the space below the throat plate 21 for a certain period of time at a slower speed than before and after. By doing so, it is possible to create a fine movement state and continue to capture the looper thread Lb. The certain period of time related to the low-speed movement starts from the time when the retainer 5 captures the looper thread Lb (at the moment shown in FIG. 7) and when the looper 4 starts reversing the movement direction related to the reciprocating movement described above (the moment shown in FIG. 10). immediately after). Further, the certain range related to the low-speed movement is a turning position where the retainer 5 reverses in the retreating (retreating) direction with the tip portion 53 in the most advanced (advanced) state, and the vicinity of the turning position, This is the range between the turning position and a position distant in the backward direction. Here, "nearby" means a range of less than 3% of the total stroke amount (corresponding to the distance from the most advanced position to the most retracted position) regarding the reciprocating motion of the retainer 5, which will be described in detail later.

Before and after the first member 61 (output arm portion 611) and the second member 62 of the link mechanism 6 are in a straight line state, tangents of the rotation loci of each member 61 (611), 62 (each member 61 (611), 62 (tangent line perpendicular to the axial direction). While this relationship is established, approximately 100% of the driving force transmitted from the first member 61 on the driving side to the second member 62 on the driven side is a force component in the direction along the tangential direction. That is, the force in the direction component perpendicular to the tangential direction is approximately 0%. On the other hand, the axial directions of the branch part of the V-shaped third member 63 that receives the driving force from the second member 62 and the second member 62 are set to be perpendicular to each other (see FIG. reference). Therefore, in the above-described directional component, the third member 63 hardly rotates due to the driving force of the second member 62. Therefore, the retainer 5 connected to the link mechanism 6 (downstream of the third member 63 in the force transmission direction) can be moved at low speed (almost stationary). As described above, in this embodiment, the retainer 5 can be moved at a low speed by reducing the amount of driving force transmitted to other members by the directional component of the force accompanying the rotation of the members constituting the link mechanism 6. .

In addition, when focusing on the proximal bent state, the link mechanism 6 goes from a straight line state to a proximal bent state and then returns to a straight line state. Since the retainer 5 can be reciprocated over a smaller distance than before, the retainer 5 can be moved at a lower speed than before and after.

The retainer 5, to which the driving force is transmitted by the link mechanism 6, is brought into the fine movement state during the reciprocating movement during the time period that includes the folding operation on the side that holds the looper thread Lb. Here, in the micro-movement state, the retainer 5 is not turned back immediately as in the conventional case (Patent Document 1 (Japanese Unexamined Patent Publication No. 2001-314681)), but instead moves at a low speed for a certain period of time and moves over a certain range. This is a state in which the retainer 5 moves in a reciprocating manner (as if the retainer 5 "steps" within a limited range). The above-mentioned "certain range" is a minute range in the direction of reciprocating motion compared to the entire range. Regarding the above-mentioned "minor range", in this embodiment, when the rotation angle of the main shaft of the sewing machine 1 is 47 degrees or more, the amount of reciprocating movement of the retainer 5 corresponding to the rotation angle is equal to the entire stroke of the movement. It is defined as being less than 3% of the distance (corresponding to the distance from the most advanced position to the most retracted position).

Therefore, the change in the moving position of the retainer 5 in this embodiment does not take the form of a constant sine curve, and on one side of the two turns, the speed of the retainer 5 decreases extremely and the fine movement occurs. state. In particular, in FIG. 11, there are two "mountains" corresponding to the folding, and there is a small "trough" between them, resulting in the above-mentioned "stepping" state. Note that "0°" on the horizontal axis shown in FIG. 11 corresponds to the position where the needle 3 is raised the most (the top dead center of the needle bar (not shown) that supports the needle 3). "180°" corresponds to the lowest position of the needle 3 (bottom dead center of the needle bar). Note that by changing the configuration of the link mechanism 6, the movement position of the retainer 5 can be changed as shown in FIG. 12. In this case, even in the same "stepping" state, as shown in the figure, there is only one "mountain" corresponding to the turn, and for example, the curvature of the sine curve becomes partially gentle, or the sine curve The moving position of the retainer 5 changes so that a "flat" portion appears in the curve.

The link mechanism 6 is provided with a bending movable part (in this embodiment, a combination of a first member 61 and a second member 62, which are link units), and receives the reciprocating movement of the transmission rod 7 to bend one side. The most bent state (proximal bent state (not shown)/the shape of a "<" bent in the opposite direction from the state in FIG. ``>'' shape). In this embodiment, the time (instant) when the vertical reciprocating motion of the transmission rod 7 is changed from downward to upward, and the output arm 611 of the first member 61 and the second It is set so that the time when the direction in which the member 62 extends becomes in a straight line (straight line state) does not coincide. In the present embodiment, the distal end portion 53 of the retainer 5 protrudes the most when the bendable movable portion is in a straight line (the state shown in FIG. 2), and when the bendable movable portion is bent (the shape of the character "<", The tip portion 53 is set so as to be retracted in both cases of the shape of a square. FIG. 3 shows the most retracted state. Therefore, even after the extending directions of the output arm portion 611 of the first member 61 and the second member 62 become in a straight line, the output arm portion 611 of the first member 61 and the second member 62 are pushed by the transmission rod 7. The bending continues. The output arm portion 611 of the first member 61 and the second member 62 are in a straight line twice before and after the bent state (specifically, the shape of the character “<”). The time between these two straight lines is the time during which the retainer 5 enters the slight movement state. Due to the relationship between the first member 61 (output arm 611) and the second member 62, the link mechanism 6 has two peaks on the graph of FIG. 11 (from 0° to 90° on the horizontal axis). As such, the retainer 5 (particularly the distal end portion 53 that captures the looper thread Lb) is once retreated from the folding position within the above-mentioned certain range, then advanced to the folding position again, and then further retreated.

Here, a case will be described in which the bending state of the output arm portion 611 of the first member 61 and the second member 62 and the change thereof are set differently. The above-mentioned bent state is such that the output arm portion 611 of the first member 61 and the second member 62 are in a straight line state, a proximal bent state (in a "<" shape), and a distal bent state (in a ">" shape). It was set to change into three states: On the other hand, as another setting, for example, it can be set to change into two states, a straight state and a bent state. In this case, the states that correspond to changes related to bending are a straight line state and a bent state. The "bent state" is the distal bent state (the state shown in FIG. 3) in the first embodiment. Even with this configuration, low-speed movement of the retainer 5 can be realized.

Still another setting is a state in which the bending is not in the straight line state but in the same direction as the bending state, and is bent more gently than the bending state (referred to as a "quasi-straight state"); It can also be set to change into two states. In this case, the states where changes related to bending are reversed are a quasi-linear state and a bent state. Even with this configuration, low-speed movement of the retainer 5 can be similarly achieved. Therefore, the link mechanism 6 can be set in various ways so as to repeatedly change in part or all of the range between the straight state and the bent state.

Next, in FIGS. 5 to 10, the needles 3 (four pieces), the looper 4, the retainer 5, the needle thread La, and the looper thread Lb are taken out, and the positional relationship of each part is shown and explained in order of operation. Note that, in some of the figures, illustration of the retainer 5 and the needle thread La is omitted for the purpose of avoiding complicating the explanation and the content of the illustration. Also, arrows attached to each part indicate the direction of movement. Further, an arrow with a horizontal bar indicates that the turning position has been reached. Each figure is a view from the distal end side of the cylinder 2 toward the proximal end side, that is, from the opposite side of the operator toward the operator (the side of the arrow OP shown in FIG. 5, etc.). The direction is also expressed based on that viewpoint.

FIG. 5 shows a state in which the looper 4 is moving to the right in the figure. At this time, the needle 3 is lowered (the needle thread La is not shown). FIG. 6 shows the state after the moving direction of the looper 4 has been reversed from the right direction in the figure to the left direction in the figure. At this time, the needle 3 has risen after reaching the bottom dead center (lowest position). Then, the needle thread La is scooped up by a looper 4 that enters below the needle 3. At this time, the looper thread Lb is passed through the loop of the needle thread La from right to left. FIG. 7 shows a state in which the looper 4 is moving to the left in the drawing. The retainer 5 moves close to the looper 4, hooks and captures the looper thread Lb that has passed through the loop of the needle thread La, and begins to hold the looper thread Lb. FIG. 8 shows a state in which the looper 4 has further moved to the left in the figure and is at the most left position in the figure. At this time, the needle 3 is at the top dead center (uppermost position). The retainer 5 is held within a certain range of positions and continues to capture the looper thread Lb. FIG. 9 shows a state after the moving direction of the looper 4 has been reversed from the left direction in the figure to the right direction in the figure. At this time, the needle 3 has descended (needle thread La is not shown) and intersects the looper 4. Even at this point, the retainer 5 is held within a certain range of positions and continues to capture the looper thread Lb. FIG. 10 shows a state in which the looper 4 has further moved to the right in the figure and is at the most right position in the figure. At this time, the needle 3 is at the bottom dead center (the needle thread La is not shown). The retainer 5 then retreats to release the looper thread Lb. Incidentally, the position where the retainer 5 captures the looper thread Lb is set to be the same as the capture position of the retainer needle, which is conventionally provided with a needle and captures the looper thread while penetrating the fabric.

Regarding the movement of the retainer 5, the retainer 5 moves at an extremely low speed at least from the time when the looper 4 is positioned furthest to the left in the figure (FIG. 8) until the needle 3 intersects with the looper 4 (FIG. 9). state. As a result, the position of the portion of the looper thread Lb held by the retainer 5 hardly changes with respect to the needle thread La, so that the looper thread Lb is pulled out as the looper 4 moves to the left, causing a large amount of the looper thread Lb to be pulled out. As it is pulled out, it is possible to form a loop of the looper thread Lb that is wider (that is, "loose") than before. Therefore, as the looper thread Lb is captured by the retainer 5, the looper thread Lb can form an annular seam with a desired spread.

At this time, the retainer 5 is in a state of moving at an extremely low speed, so as in the conventional case (Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2001-314681)), the retainer continues to reciprocate at a constant speed and moves the looper thread. Compared to the configuration in which the looper thread Lb is held, the amount of movement of the retainer 5 while holding the looper thread Lb can be reduced. Therefore, since the amount of movement of the retainer 5 can be reduced, the volume occupied by the retainer 5 inside the cylinder 2 can be reduced, and the retainer 5 can be stored compactly in the cylinder 2.

Here, the movement locus of the retainer 5 is schematically shown in the graph of FIG. The horizontal axis of the graph is the time axis (specifically, the angle is expressed based on the top dead center and bottom dead center of the needle 3 and the needle bar supporting it), and the vertical axis is the displacement related to reciprocating motion. As a conventional example, the retainer 5 described in Patent Document 1 makes a simple reciprocating motion, and although not shown, the movement trajectory of the retainer 5 is a simple sine curve. In order to hold the looper thread Lb for a long time with such a simple reciprocating motion, it is necessary to increase the stroke of the reciprocating motion of the retainer 5. In this case, there is a possibility that the reciprocating range of the retainer 5 will not fit inside the cylinder 2.

On the other hand, the movement locus of the retainer 5 in this embodiment is shown in FIG. 11, for example. As is clear from the graph, two small low mountains are formed in the range including 0° to 90° on the horizontal axis. The fact that two small peaks are formed on the graph means that the tip 53 of the retainer 5 reciprocates within a minute range. In this way, by "stepping" the retainer 5 with respect to the looper 4 within a limited range, the retainer 5 does not turn back immediately, but remains in a narrow range within the reciprocating range for a certain period of time. I can do it. By doing so, the looper thread Lb can be held without increasing the reciprocating range of the retainer 5.

Although the first embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist of the present invention.

For example, the low-speed movement mechanism that is configured to move the retainer 5 at a low speed for a certain period of time within a certain range of positions is not limited to the link mechanism of each of the embodiments described above, and can be implemented in various configurations. For example, as a mechanical configuration, a configuration including a cam, a gear with no teeth formed in part, a combination of a plurality of gears that approach and separate, a clutch mechanism, and a brake mechanism that performs deceleration by friction can be considered. Moreover, as an electrical configuration, a configuration having an electric circuit that connects and disconnects transmission of driving force at predetermined time intervals can be considered. Further, in each of the above embodiments, the low-speed movement mechanism was provided at one location in the driving force transmission path, but instead, the low-speed movement mechanism is provided separately at multiple locations, and each of the separate mechanisms may be configured to operate simultaneously or with a time lag.

[Second embodiment]
Further, the driving force for moving the retainer 5 can also be obtained from a looper shaft that is a shaft for driving the looper 4 or a feed base. Further, the retainer 5 can be moved by a drive mechanism independent of the mechanism for driving other parts of the sewing machine. The "second embodiment" will be illustrated below.

As a second embodiment, an example of a configuration in which the driving force for the retainer 5 is obtained from the looper shaft 11 is shown in FIGS. 13 and 14. Further, the movement locus of the retainer 5 in the second embodiment is schematically shown in the graph of FIG. In the second embodiment, the retainer shaft 12 is provided so that its axial direction is parallel to the looper shaft 11 driven by a main shaft (not shown) connected to the base end side. A retainer support portion 14 is integrally provided at the tip of the retainer shaft 12. The axial directions of the looper shaft 11 and the retainer shaft 12 are along the longitudinal direction of the cylinder 2, and the distance between the centers of each axis is constant. The looper shaft 11 and the retainer shaft 12 are connected by a link mechanism 13 so that driving force can be transmitted. The link mechanism 13 includes a looper-side link body 131 and a connection link body 132 as link units. The connecting link body 132 is connected to a link receiving portion 121 that is integrally provided on the base end side of the retainer shaft 12 . The looper shaft 11 rotates within a predetermined angular range to move the looper 4 forward and backward. Correspondingly, the link mechanism 13 is in the state shown in FIG. 13 and in the state shown in FIG. 14 (more specifically, the state shown in FIG. Repeat the bending condition shown in Figure 1).

The retainer 5 in the second embodiment has a rod-like body bent into an "L" shape and has a hook shape. The retainer 5 has a base portion 54 extending in the radial direction attached to the retainer support portion 14, and is captured by hooking the looper thread Lb at a distal end portion 55 that is integrally provided on the radially outer side of the base portion 54. As mentioned above, the looper shaft 11 and the retainer shaft 12 are parallel, and the looper 4 and retainer 5 rotate (swing) at the tips of each shaft, so the tip 55 of the retainer 5 is attached to the looper 4. It reciprocates in the direction along the cylinder (that is, the direction perpendicular to the longitudinal direction of the cylinder 2).

By adjusting the timing between the bent state and the straight state in the link mechanism 13, the retainer 5 of the second embodiment holds the looper thread (not shown) during reciprocating movement, similar to the first embodiment. The above-mentioned fine movement state can be achieved in the time interval between the side turning operations. In the second embodiment, as shown in FIG. 15, a section sandwiching the lowest position of the needle 3 (bottom dead center of the needle bar) corresponding to "180°" on the horizontal axis corresponds to the time section; Two small low mountains have formed in the area. This state corresponds to between the state shown in FIG. 14 and the reversely bent state. The capture of the looper thread Lb by the distal end portion 55 of the retainer 5 is similar to capture by a conventional retainer needle in terms of timing. The reason why the position of the peak is different from that in the first embodiment is that the relationship in the reciprocating direction of the looper 4 and the retainer 5 is orthogonal in the first embodiment, whereas in the second embodiment, the relationship is parallel. This is because the timing for holding the looper thread differs in each embodiment. The above is the description of the second embodiment.

[Third embodiment]
In the first embodiment, as shown in FIGS. 2 and 3, the connections between the adjacent members 61 to 66 are connections that are rotatable around an axis at a fixed position (round holes and round rods). combination of axes). However, the present invention is not limited to this, and at one or more connecting points, a rotation shaft (round bar shape) is located inside the formed elongated hole or groove, and together with the rotation, it rotates within the range of the elongated hole or groove. It is also possible to configure the shaft to be displaced. With this configuration, even if one of the adjacent members 61 to 66 moves (on the upstream side of the driving force transmission path), the displacement will not be transmitted to the other (downstream side of the driving force transmission path). Alternatively, the drive force can be transmitted only slightly, and the retainer 5 located at the most downstream side of the drive force transmission path can be moved at an extremely low speed, as in the embodiment described above. As a specific example, a form in which a groove is provided will be described below as a "third embodiment". Note that configurations that are common to the first embodiment will be described with the same reference numerals in the third embodiment (for convenience of explanation, some configurations are given different names from the first embodiment). .

The retainer movement mechanism 6 in the third embodiment has an input-side rotation member 61 provided on the input side that rotates within a certain range, and an input-side rotation member 61 that is provided on the output side and rotates within a certain range in the order in which the driving force for operating the retainer 5 is transmitted. It includes an output-side rotation member 63 that rotates within a range, and a displacement transmission mechanism 67 that transmits displacement from the input-side rotation member 61 to the output-side rotation member 63. The displacement transmission mechanism 67 transmits the input side rotating member 61 due to the angular relationship between the tangential component of the rotational displacement of the input side rotating member 61 and the tangential component of the rotational displacement of the output side rotating member 63. The amount of displacement transmitted from to the output side rotating member 63 is temporarily reduced.

The angular relationship of the tangential components mentioned above will be explained. When the tangential component of the rotational displacement of the input-side rotation member 61 and the tangential component of the rotational displacement of the output-side rotation member 63 are orthogonal, the input-side rotation member 61 rotates. Also, since the component corresponding to the tangential component of the rotational displacement of the output side rotation member 63 in the rotational force of the input side rotation member 61 is 0, it is not transmitted to the output side rotation member 63 as rotation force. . That is, the amount of displacement transmitted from the input-side rotation member 61 to the output-side rotation member 63 temporarily decreases (in this case, it becomes 0). Note that the rotational force of the input-side rotational member 61 is only absorbed by positional deviation within the displacement transmission mechanism 67.

In the third embodiment, the ends of the rotation range of the input side rotation member 61 are set so as to correspond to the orthogonal relationship of the tangential components in each rotation displacement of the input side rotation member 61 and the output side rotation member 63. (the position where the first output arm part 613 is at the upper end of the rotation range (top dead center)), the tangential component of the rotational displacement of the input-side rotation member 61 is arranged substantially along the extension direction of the groove part 671. (See the rotation locus of the first output arm 613 shown in FIG. 19).

Incidentally, temporarily reducing the amount of displacement transmitted from the input-side rotation member 61 to the output-side rotation member 63 due to the angular relationship of the tangential direction component is the link mechanism 6 as the retainer movement mechanism of the first embodiment. This also applies between the first member 61 as the input-side rotation member and the third member 63 as the output-side rotation member, and the second member 62 of the first embodiment has the displacement explained in the third embodiment. This corresponds to the transmission mechanism 67. In the first embodiment, the first member 61 (of which the output arm portion 611) and the second member 62 are bent to cause a positional shift and absorb the rotational force of the input-side rotational member 61. Similarly, this also applies between the looper-side link body 131 and the link receiving part 121 in the link mechanism 13 as the retainer movement mechanism of the second embodiment, and the connection link body 132 of the second embodiment is the same as that of the third embodiment. This corresponds to the displacement transmission mechanism 67 described above. Here, in the second embodiment, the looper side link body 131 corresponds to the input side rotation member 61 of the third embodiment, and the retainer shaft 12 corresponds to the output side rotation member 62 of the third embodiment. In the second embodiment, the looper side link body 131 and the connection link body 132 are bent to cause a positional shift and absorb the rotational force of the looper side link body 131. Therefore, even if the first embodiment and the second embodiment have different specific configurations, at least some of the effects performed by the third embodiment are common.

The third embodiment is specifically configured as shown in FIGS. 16 to 19. Note that, although the fourth member 64 and the fifth member 65 in particular are significantly different in shape from the first embodiment (see FIG. 2), there is no major difference in function. The input-side rotation member 61 has a first input arm portion 612 and a first output arm portion 613 (rotation movement is indicated by a curved arrow in FIG. 19) that extend in different radial directions from the first rotation center 61c. , the driving force inputted from the first input arm 612 by the operation of the transmission rod 7 is outputted from the first output arm 613 as rotational force about the first rotation center 61c. The output-side rotation member 63 has a second input arm 631 and a second output arm 632 (rotation movement is indicated by a curved arrow in FIG. 19) extending in different radial directions from 63c. The driving force input from the section 631 is outputted from the second output arm section 632 as rotational force about the second rotation center 63c.

The displacement transmission mechanism 67 includes a groove 671 provided in the second input arm 631 and extending parallel to the radial direction passing through the second rotation center 63c, and a groove 671 provided in the first output arm 613. The slide member 672 is provided and has a slide member 672 that moves along the groove portion 671. The groove portion 671 has a rectangular cross-sectional shape, and has a constant shape in the extending direction. The slide member 672 includes a shaft portion 6721 provided integrally with the first output arm portion 613 and a slide block portion 6722 rotatably provided around the shaft portion 6721. The shaft portion 6721 has a round bar shape, and the slide block portion 6722 has a rectangular parallelepiped shape, and a hole (the illustrated form is a through hole, but a hole with a bottom may be provided) into which the shaft portion 6721 is inserted is provided in the center. The slide block portion 6722 moves along the extending direction of the groove portion 671 while coming into contact with the inner surface of the groove portion 671. In other words, the slide member 672 slides with respect to the groove portion 671.

As shown in FIG. 19, the displacement transmission mechanism 67 configured by the combination of the groove portion 671 and the slide member 672 allows the first rotation center 61c of the input side rotation member 61 and the second rotation center of the output side rotation member 63 to be rotated. The input-side rotation member 61 and the output-side rotation member 63 can be rotated while the linear distance from the center of motion 63c remains constant. In other words, the displacement transmission mechanism 67 transmits displacement from the input side rotation member 61 to the output side rotation member 63 while allowing positional deviation between the input side rotation member 61 and the output side rotation member 63. It is configured. Due to the change accompanied by this positional shift, it is possible to temporarily reduce the amount of displacement transmission. The movement position of the retainer 5 can be changed in the same manner as shown in FIG.

Note that the displacement transmission mechanism 67 is not limited to the above-described configuration in terms of the relationship between the input-side rotation member 61 and the output-side rotation member 63. The portion where the groove portion 671 and the slide member 672 are provided may be reversed from the above-described configuration. In other words, the displacement transmission mechanism 67 is provided in the first output arm 613 or the second input arm 631, and has a groove extending parallel to the radial direction passing through the first rotation center 61c or the second rotation center 63c. 671 , and a slide member 672 that is provided on the second input arm 631 or the first output arm 613 and moves along the groove 671 .

The configuration and operation of the embodiment will be summarized below. In the embodiment, the needle 3 holds the needle thread La and moves up and down through the throat plate 21, and the needle 3 holds the looper thread Lb and moves reciprocally in the space below the throat plate 21 to move the needle thread A looper 4 that entangles the looper thread Lb with La, a retainer 5 that reciprocates in the space below the throat plate 21 and captures the looper thread Lb, and a driving force from a drive source is transmitted to the retainer 5. and a retainer movement mechanism 6 that changes the movement state of the retainer 5, and the retainer movement mechanism 6 moves the retainer 5 in a certain range of positions in a space below the throat plate 21 for a certain period of time. The sewing machine 1 maintains the state in which the retainer 5 captures the looper thread Lb by performing the reciprocating motion so as to move the looper thread Lb at a lower speed than before and after.

According to this configuration, the retainer movement mechanism 6 causes the retainer 5 to reciprocate in a certain range of positions in the space below the throat plate 21 for a certain period of time at a lower speed than before and after. , the retainer 5 maintains the state in which the looper thread Lb is captured. Therefore, compared to a configuration in which the retainer 5 is not moved at a low speed, the looper thread Lb can be held for a long time due to the reduced speed during the low speed movement, so there is no need to enlarge the range in which the retainer 5 reciprocates. Note that the above-mentioned "low-speed movement" also includes a case where the speed is 0 (stopped state). In addition, to paraphrase the case where the speed is 0, "the retainer movement mechanism 6 moves the retainer 5 in a certain range of positions in the space below the needle 21 plate for a certain period of time, and compares the front and back. ``The reciprocating movement is performed so that the robot moves at a low speed, or waits at a speed of 0.''

The certain range related to the low-speed movement of the retainer 5 by the retainer movement mechanism 6 is a turn-back position where the retainer 5 reverses from the forward direction to the backward direction, and the vicinity of the turn-back position. and a position distant in the backward direction.

Further, the retainer movement mechanism 6 may cause the retainer 5 to once retreat from the folded position within the certain range, then advance to the folded position again, and then further retreat.

According to these configurations, the retainer 5 repeatedly moves forward and backward at low speed near the turning position. Therefore, the structure of the retainer movement mechanism 6 can be simplified compared to a structure in which the retainer movement mechanism 6 is completely stopped at a fixed time. Note that the above-mentioned "complete stop within a certain period of time" does not include an instantaneous stop due to turnaround.

The retainer movement mechanism 6 includes a link mechanism 6 in which two link units 62 are combined, and the link mechanism 6 is connected to the input side of each of the link units by inputting reciprocating motion. The straight line connecting the point and the output side connecting point is configured to repeatedly change in a part or all range between a straight line state and a bent state, and at least the link mechanism The retainer 5 may be configured to continue to capture the looper thread Lb while the bending state disappears at the end of the looper thread Lb and the bending state returns to the end of the change and starts bending again.

According to this configuration, the retainer 5 can be reciprocated over a small distance between before and after the state where the link mechanism 6 is in a straight line state or when the change is turned around, so the retainer 5 can be moved at a lower speed than before and after that state. I am made to do so. Therefore, the link mechanism 6 can realize low-speed movement.

The retainer movement mechanism 6 is provided with a link mechanism 6 in which two link units 61 are combined, and the link mechanism 6 receives reciprocating motion, so that the input side of each of the link units 61 is The straight lines connecting the connecting point and the output side connecting point are configured to repeat a proximal bent state bent in one direction, a straight line state lined up in a straight line, and a distal bent state bent in the other direction, and the straight line is bent in the straight line state. On the other hand, in the proximal bent state, the bending point between both link units 61 is set closer than in the distal bent state, and at least the link mechanism changes from the straight line state to the proximal bent state. The retainer 5 may be configured to continue to capture the looper thread Lb until it returns to the straight line state again.

According to this configuration, the retainer 5 can be reciprocated over a small distance while the link mechanism 6 changes from the straight line state to the proximal bent state and returns to the straight line state. 5 can be moved at low speed. Therefore, the link mechanism 6 can realize low-speed movement.

The retainer movement mechanism 6 includes an input side rotating member 61 that is provided on the input side and rotates within a certain range, an output side rotating member 63 that is provided on the output side and rotates within a certain range, and the input side rotating member 63 that is provided on the output side and rotates within a certain range. a displacement transmission mechanism 67 that transmits displacement from the rotation member 61 to the output side rotation member 63; Temporarily reduces the amount of displacement transmitted from the input side rotation member 61 to the output side rotation member 63 due to the angular relationship with the tangential component of the rotational displacement of the output side rotation member 63. It can be done.

According to this configuration, the retainer 5 is moved at a low speed due to the angular relationship between the tangential component of the rotational displacement of the input side rotational member 61 and the tangential direction component of the rotational displacement of the output side rotational member 63. can be realized.

The input-side rotating member 61 has a first input arm 612 and a first output arm 613 that extend in different radial directions from the first rotation center 61c. The generated driving force is output from the first output arm portion 613 as a rotational force around the first rotation center 61c, and the output side rotation member 63 is rotated in a different radial direction from the second rotation center 63c. It has an extending second input arm 631 and a second output arm 632, and the driving force input from the second input arm 631 is transferred from the second output arm 632 to the second rotation center 63c. Outputs as rotating force around the
The displacement transmission mechanism 67 is provided in the first output arm 612 or the second input arm 632, and is arranged in a radial direction passing through the first rotation center 61c or the second rotation center 63c. It may include a groove 671 extending in parallel, and a slide member 672 that is provided on the second input arm 632 or the first output arm 612 and moves along the groove 671.

According to this configuration, low-speed movement of the retainer 5 can be realized by the combination of the groove portion 671 and the slide member 672.

According to the embodiment, the looper thread Lb can be held for a long time during low-speed movement compared to a configuration in which the retainer 5 is not moved at variable speeds, so there is no need to increase the range in which the retainer 5 reciprocates. Therefore, the time for which the retainer 5 holds the looper thread Lb can be extended without setting a large reciprocating stroke of the retainer 5, and as a result, a seam in which the looper thread Lb has a desired spread can be realized. play.

1 Sewing machine 2 Cylinder 21 Throat plate 3 Needle 4 Looper 5 Retainer 6 Retainer movement mechanism (first and third embodiments), link mechanism (first embodiment)
61 Link unit (first embodiment), first member (first embodiment), input side rotation member (third embodiment)
61c First rotation center 612 First input arm 613 First output arm 62 Link unit, second member (first embodiment)
63 Third member (first embodiment), output side rotating member (third embodiment)
63c Second rotation center 631 Second input arm 632 Second output arm 67 Displacement transmission mechanism (third embodiment)
671 Groove 672 Slide member 13 Retainer movement mechanism (second embodiment), link mechanism (second embodiment)
131 Link unit body (second embodiment), looper side link body (second embodiment)
132 Link unit body (second embodiment), connection link body (second embodiment)
La Needle thread Lb Looper thread OP Side facing the operator

Claims

A needle that holds the needle thread and moves up and down through the throat plate,
a looper that holds a looper thread and reciprocates in a space below the throat plate to entangle the looper thread with the needle thread;
a retainer that reciprocates in a space below the throat plate and captures the looper thread;
a retainer movement mechanism that changes the movement state of the retainer while transmitting a driving force from a drive source to the retainer,
The retainer movement mechanism is configured to cause the retainer to reciprocate in a predetermined range of positions in a space below the throat plate for a predetermined period of time at a lower speed than before and after the reciprocating motion, so that the retainer moves toward the looper. A sewing machine that keeps the thread in a captured state.
The certain range of the low-speed movement of the retainer by the retainer movement mechanism is
The sewing machine according to claim 1, wherein the sewing machine is in a range between a turning position where the retainer reverses from the forward direction to the backward direction and a position near the turning position and away from the turning position in the backward direction. .
3. The sewing machine according to claim 2, wherein the retainer movement mechanism moves the retainer once backward from the folded-back position within the certain range, then moves the retainer forward again to the folded-back position, and then moves the retainer further back.
The retainer movement mechanism includes a link mechanism in which two link units are combined,
In the link mechanism, when a reciprocating motion is input, the straight lines connecting the input-side connection point and the output-side connection point of each of the link units are arranged in a straight line state and in a bent state. It is configured to repeat changes in some or all of the ranges between
At least, the retainer is configured to continue to capture the looper yarn while the bending state of the link mechanism is resolved, the change is turned around, and the bending starts again. The sewing machine according to item 1.
The retainer movement mechanism includes a link mechanism in which two link units are combined,
When reciprocating motion is input to the link mechanism, the straight lines connecting the input side connection point and the output side connection point in each of both link units are in a proximal bent state bent in one direction, and lined up in a straight line. It is configured to repeat a straight line state and a distal bent state bent in the other direction, and the bending point between both link unit bodies is closer in the proximal bent state than in the distal bent state compared to the straight line state. is set,
Claim 1: The retainer is configured to continue to capture the looper thread at least until the link mechanism passes from the straight line state to the proximal bent state and returns to the straight line state. The sewing machine described in
The retainer movement mechanism includes an input-side rotation member that is provided on the input side and rotates within a certain range, an output-side rotation member that is provided on the output side and rotates within a certain range, and a rotation member that rotates in a certain range from the input-side rotation member. a displacement transmission mechanism that transmits displacement to the output side rotating member;
The displacement transmission mechanism is configured such that the input side rotation member is controlled by the angular relationship between the tangential component of the rotational displacement of the input side rotation member and the tangential direction component of the rotational displacement of the output side rotation member. 2. The sewing machine according to claim 1, wherein the amount of displacement transmitted from the output rotating member to the output rotating member is temporarily reduced.
The input-side rotation member has a first input arm and a first output arm that extend in different radial directions from the first rotation center, and transfers the driving force input from the first input arm to the Output from the first output arm as rotational force around the first rotation center,
The output-side rotation member has a second input arm and a second output arm extending in different radial directions from the second rotation center, and transfers the driving force input from the second input arm to the Output from the second output arm as rotational force around the second rotation center,
The displacement transmission mechanism includes a groove portion provided in the first output arm portion or the second input arm portion and extending parallel to a radial direction passing through the first rotation center or the second rotation center. 7. The sewing machine according to claim 6, further comprising: a slide member that is provided on the second input arm or the first output arm and moves along the groove.