JP2010057906A - Bottom and top feed sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the speed of a top feed foot when the top feed foot lands on a workpiece. <P>SOLUTION: A bottom and top feed sewing machine includes a feed dog 14 and a top feed foot 12 which contact the workpiece on a throat plate from below and above respectively to perform a feeding operation, a bottom side rear-and-aft feed mechanism 70 which drives the feed dog back and forth, a bottom side up-and-down feed mechanism 80 which drives the feed dog up and down, a top side rear-and-aft feed mechanism 40 which drives the top feed foot back and forth, and a top side up-and-down feed mechanism 50 which drives the top feed foot in an up and down direction. The top side up-and-down feed mechanism includes a cam mechanism 60 which takes out a reciprocating movement from a rotational movement of a rotary shaft 16 which performs a rotational drive. The cam mechanism includes a triangular cam 61 having an outer circumference, a shape of which is obtained by connecting two kinds of circular arcs, each of three vertices of an equilateral triangle being a center of small and large circular arcs, and a cam follower 62 having receiving surfaces 65, 66 which hold the triangular cam therebetween. The triangular cam is fixed and supported on the rotary shaft so as to rotate around a position, which is on a perpendicular line drawn down to a base from one of the vertices and is closer to the base than the center of the equilateral triangle is, and such that, when a needle bar which performs stitching by an up-and-down movement is located at the upper dead point of the up-and-down movement, the top feed foot is located at the upper dead point of the reciprocating movement along the up-and-down direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vertical feed sewing machine having an upper feed leg.

A conventional vertical feed sewing machine has a feed dog that reciprocates in the front-rear direction of cloth feed while appearing from below the needle plate, and a feed leg that moves in the front-rear direction while moving up and down from the needle plate in synchronization with the feed dog. A feed dog side longitudinal feed mechanism that imparts a forward and backward reciprocating motion to the feed dog, a feed dog side vertical feed mechanism that imparts a vertical reciprocation motion to the feed dog, and a forward and backward reciprocating motion to the feed leg. It includes a forward / backward feed mechanism on the feed leg side and a vertical feed mechanism on the feed leg side that imparts a vertical reciprocating motion to the feed leg.
The vertical feed mechanism on the feed leg side is configured to reciprocate by a circular eccentric cam fixedly mounted on the upper shaft, an upper and lower rod engaged with the eccentric cam at one end, and a longitudinal reciprocation of the upper and lower rod. A vertical feed arm that moves and a bell crank that rotates as the vertical feed arm reciprocates is provided, and the vertical movement is transmitted from the bell crank to the feed leg.
On the other hand, the forward / backward feed mechanism on the feed foot side includes a middle shaft to which a reciprocating rotation operation is transmitted from a lower shaft that performs reciprocating rotation, and a middle shaft front arm fixed to the middle shaft. The reciprocating motion of the end portion in the front-rear direction is transmitted to the feed leg.
Then, the upper and lower reciprocating motions and the front and rear reciprocating motions by the front and rear feeding mechanisms are appropriately adjusted to each other and transmitted to the feeding foot to cause the feeding foot to perform an ellipse motion. Using the lower half of the movement trajectory, the feed movement by the feed leg was realized.

Japanese Patent No. 3629414

FIG. 14 is a diagram showing a positional displacement D and a velocity displacement V corresponding to the vertical direction of the feed foot generated by the circular eccentric cam of the above-described vertical feed mechanism on the feed foot side.
In the above-mentioned conventional vertical feed sewing machine, since the vertical feed mechanism on the feed foot side takes up and down reciprocating motion from the upper shaft by a circular eccentric cam, the position displacement D draws a substantially cosine curve and is displaced by lowering. When the point reaches approximately 0 point (point G in the figure), the feed leg is made to land on the sewing material on the needle plate (in FIG. 14, the zero point of displacement indicates the height of the needle plate). Actually, the feed leg cannot move below the needle plate, but here, for convenience of explanation, if the needle plate does not exist, a diagram is displayed according to a locus that would be drawn).
On the other hand, as shown in the figure, the speed displacement V of the feed leg is the fastest at the point G where the landing is made, so that the impact at the time of landing increases, the impact sound and vibration increase, and the durability of the machine deteriorates. There was a problem that. To deal with this, there are methods such as increasing the strength of the feed leg and its support structure, but in that case, the sewing machine manufacturing cost will increase, such as making parts larger or using expensive, high-quality materials. There was a drawback that it would.

  An object of the present invention is to reduce the speed at the time of landing of the upper feed leg.

  The invention according to claim 1 is a feed dog that performs a feed operation by contacting the workpiece on the needle plate from below, an upper feed leg that performs a feed operation by contacting the workpiece on the needle plate from above, A lower back-and-forth feed mechanism that imparts a reciprocating motion along the feed direction to the feed dog, a lower vertical feed mechanism that imparts a reciprocating motion along the vertical direction to the feed dog, and a feed direction to the upper feed foot in the feed direction An upper back-and-forth feed mechanism for providing a reciprocating motion along the upper and lower feed mechanisms for imparting a reciprocating motion along the vertical direction to the upper feed foot. In a vertical feed sewing machine that feeds a sewing product, the upper vertical feed mechanism includes a cam mechanism that takes out a reciprocating motion from a rotational motion of a rotary shaft that performs rotational driving, and the cam mechanism is provided at each of three vertexes of an equilateral triangle. Two large and small arcs centered on An outer peripheral triangular cam, and a cam follower having at least one pair of receiving surfaces facing each other so as to sandwich the triangular cam, wherein the triangular cam is one of the vertices. Is fixed to the rotary shaft so as to rotate about a position on the base side from the center point of the equilateral triangle, and the vertical movement of the upper feed leg. The triangular cam is fixedly supported on the rotary shaft so that the top dead center and the top dead center of a needle bar which is sewn by vertical movement coincide with each other.

  The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and the bottom of the triangular cam closest to the rotating shaft is vertically or horizontally at the top dead center of the needle bar. The rotating shaft is fixedly supported so as to face.

  The invention according to claim 3 has the same configuration as that of the invention according to claim 1 or 2, and the triangular cam has a distance from the vertex to the center of rotation of one side of the equilateral triangle. It is characterized by being 0.7 or more and 1.0 or less.

  The invention according to claim 4 has the same configuration as that of the invention according to claim 3, and the triangular cam has the position of the rotation center as an intersection of the perpendicular and the bottom with respect to the apex. And

  The invention according to claim 5 is a feed dog that performs a feed operation by contacting the workpiece on the needle plate from below, an upper feed leg that performs a feed operation by contacting the workpiece on the needle plate from above, A lower back-and-forth feed mechanism that imparts a reciprocating motion along the feed direction to the feed dog, a lower vertical feed mechanism that imparts a reciprocating motion along the vertical direction to the feed dog, and a feed direction to the upper feed foot in the feed direction An upper back-and-forth feed mechanism for providing a reciprocating motion along the upper and lower feed mechanisms for imparting a reciprocating motion along the vertical direction to the upper feed foot. In a vertical feed sewing machine that feeds a sewing product, the upper vertical feed mechanism includes a cam mechanism that takes out a reciprocating motion from a rotational motion of a rotary shaft that performs rotational driving, and the cam mechanism is provided at each of three vertexes of an equilateral triangle. Two large and small arcs centered on A triangular cam having an outer peripheral shape and a cam follower having at least two pairs of receiving surfaces facing each other so as to sandwich the triangular cam, and the triangular cam is one of the vertices. The follower body is reciprocated by a combined displacement of the displacements received by the two sets of receiving surfaces, so that the upper feed leg can be moved up and down. The triangular cam is fixedly supported on the rotary shaft so that the top dead center and the top dead center of a needle bar which is sewn by vertical movement coincide with each other.

  The invention according to claim 6 has the same configuration as that of the invention according to claim 5, and the base farthest from the apex located at the center of rotation of the triangular cam is the top dead center of the needle bar in the vertical direction. Two sets of receiving surfaces parallel to each other of the cam follower are 40 to 50 ° with respect to the reciprocating direction at the top dead center of the needle bar. It is characterized by tilting in the range of

  The invention described in claim 7 has the same configuration as that of the invention described in claim 5 or 6, and both of the two parallel receiving surfaces are inclined at 45 ° with respect to the reciprocating direction. It is characterized by.

According to the first or second aspect of the invention, the cam mechanism of the upper vertical feed mechanism receives the displacement by the at least one set of receiving surfaces with respect to the triangular cam whose rotation center is offset to take out the reciprocating operation. The triangular cam has a characteristic of greatly decelerating at a substantially intermediate position from one maximum displacement to the other maximum displacement with respect to the fixed position displacement in the reciprocating direction. Therefore, the triangular cam is attached to the rotating shaft so that the top dead center of the vertical movement of the upper feed leg and the top dead center of the needle bar that is sewn by the vertical movement coincide with each other. By applying it to the vertical movement, it is possible to decelerate at an intermediate position from the top dead center to the bottom dead center of the upper feed leg, and the situation where the descending speed becomes the fastest when the upper feed leg lands. The impact can be reduced by the low-speed landing, the durability of the mechanism can be improved, and the smashing of the workpiece can be avoided. Accordingly, it is possible to avoid an increase in production cost due to the strengthening of the upper feed leg.
In addition, since the present invention uses a triangular cam having a geometric shape whose outer shape is determined by a function, it is much easier to design and manufacture compared to a case where a unique cam that produces the same characteristics is designed and manufactured. Manufacturing can be performed, and production costs can be reduced.

  Furthermore, according to the third aspect, it is possible to further reduce the speed at the time of landing of the upper feed leg, and it is possible to further improve the durability of the mechanism, protect the sewing object, and reduce the cost.

  Furthermore, according to claim 4, since the speed can be substantially zero at the midpoint of the maximum amplitude, the descending speed can be substantially zero when the upper feed leg is landed, and the durability of the mechanism is further improved. It becomes possible to realize protection of the workpiece and cost reduction.

In the invention according to claim 5 or 6, the cam mechanism of the upper vertical feed mechanism receives displacement by at least two sets of receiving surfaces with respect to the triangular cam, and extracts the reciprocating operation from the combined displacement. The triangular cam has a characteristic of generating a large deceleration at a substantially intermediate position from one maximum displacement to the other maximum displacement by combining two positional displacements in the reciprocating direction. Therefore, the triangular cam is attached to the rotating shaft so that the top dead center of the vertical movement of the upper feed leg and the top dead center of the needle bar that is sewn by the vertical movement coincide with each other. By applying it to the vertical movement, it is possible to decelerate at an intermediate position from the top dead center to the bottom dead center of the upper feed leg, and the situation where the descending speed becomes the fastest when the upper feed leg lands. The impact can be reduced by the low-speed landing, the durability of the mechanism can be improved, and the smashing of the workpiece can be avoided. Accordingly, it is possible to avoid an increase in production cost due to the strengthening of the upper feed leg.
In addition, since the present invention uses a triangular cam having a geometric shape whose outer shape is determined by a function, it is much easier to design and manufacture compared to a case where a unique cam that produces the same characteristics is designed and manufactured. Manufacturing can be performed, and production costs can be reduced.

  Furthermore, according to the seventh aspect, it is possible to further reduce the speed at the time of landing of the upper feed leg, and it is possible to further improve the durability of the mechanism, protect the sewing object, and reduce the cost.

It is a mechanism diagram which shows schematic structure of the comprehensive feed sewing machine which is 1st embodiment. It is explanatory drawing which showed the external shape of the triangular cam in detail. It is a block diagram of the cam mechanism seen from the surface part side of the general feed sewing machine. It is explanatory drawing which shows the displacement of the X-axis direction which arises in the engaging part of a vertical movement rod with rotation of a triangular cam. It is a diagram which shows the position displacement and speed displacement which arise in the fixed direction of a triangular cam in the case of the coefficient k = 0.7. It is a diagram which shows the position displacement and speed displacement which arise in the fixed direction of a triangular cam in case coefficient k = 0.8. It is a diagram which shows the position displacement and speed displacement which arise in the fixed direction of a triangular cam in the case of the coefficient k = 0.866. It is a diagram which shows the position displacement and speed displacement which arise in the fixed direction of a triangular cam in the case of the coefficient k = 0.9. It is a diagram which shows the position displacement and speed displacement which arise in the fixed direction of a triangular cam in the case of the coefficient k = 1.0. It is a block diagram of the cam mechanism of 2nd embodiment seen from the surface part side of the comprehensive feed sewing machine. It is a block diagram of the cam mechanism of 3rd embodiment seen from the surface part side of the comprehensive feed sewing machine. It is a block diagram of the cam mechanism of 4th embodiment seen from the surface part side of the comprehensive feed sewing machine. It is a diagram which shows the position displacement and speed displacement which arise in a fixed direction by the cam mechanism of 4th embodiment. It is a diagram which shows the position displacement and speed displacement which arise in a fixed direction with the conventional cam mechanism.

(Overall configuration of the first embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. In the present embodiment, a general feed sewing machine 10 which is a kind of vertical feed sewing machine will be described as an example. The total feed sewing machine 10 alternately moves up and down alternately with the needle bar 11 that holds the sewing needle, the upper feed leg 12 that performs a feed operation while touching the workpiece on the needle plate from above, and the upper feed leg 12. The presser foot 13 to be performed, the feed dog 14 that performs a feed operation while coming into contact with the workpiece on the needle plate from below, the sewing machine motor 15 that is the main drive source of the sewing operation, and the rotational drive by the sewing machine motor 15 An upper shaft 16 as a rotation shaft, a lower shaft 18 that is rotationally driven by the sewing machine motor 15 via the upper shaft 16 and the timing belt 17, a needle vertical movement mechanism 30 that moves the needle bar 11 up and down, the needle bar 11, An upper back-and-forth feed mechanism 40 that imparts a back-and-forth back-and-forth movement along the cloth feed direction to the upper feed leg 12, an upper-side up-and-down feed mechanism 50 that provides a top and bottom reciprocation to the upper feed leg 12 and the presser foot 13, 14 in the cloth feed direction A lower back-and-forth feed mechanism 70 for applying a back-and-forth back-and-forth motion, a lower up-and-down feed mechanism 80 for providing a back-and-forth reciprocating motion to the feed dog 14, and a feed adjustment mechanism 90 for adjusting the feed amount of the feed dog 14. And a sewing machine frame 2 that supports the above-described components.
In the following description, the direction parallel to the upper surface of the needle plate of the total feed sewing machine 10 and along the cloth feed direction is defined as the X-axis direction, and the direction parallel to the upper surface of the needle plate of the sewing machine and perpendicular to the X-axis direction. The Y-axis direction and the direction perpendicular to the needle plate of the sewing machine are defined as the Z-axis direction. Further, it is assumed that the needle plate of the general feed sewing machine 10 is provided such that the upper surface thereof is horizontal when the sewing machine 10 is installed on a horizontal plane.

(Needle vertical movement mechanism)
The needle up-and-down movement mechanism 30 has a rotating weight 31 (shown by a simple straight line in FIG. 1) fixedly mounted on one end of the upper shaft 16 along the Y-axis direction, and one end at a position eccentric from the rotation center of the rotating weight 31. An eccentric rod 32 whose part is rotatably supported is provided, and a needle bar holder 33 fixed to the needle bar 11 is provided.
One end of the eccentric rod 32 is supported on the rotary weight 31 by a support shaft along the Y-axis direction, and the other end is connected to the needle bar holder 33 by a support shaft along the Y-axis direction.
With this configuration, the needle up-and-down movement mechanism 30 can apply the rotational movement of the upper shaft 16 to the needle bar 11 instead of the reciprocating movement in the up-down direction.

(Lower vertical feed mechanism)
The lower vertical feed mechanism 80 includes a vertical movement cam 81 that is a circular eccentric cam fixedly supported by the lower shaft 18 along the Y-axis direction, and a vertical movement rod that rotatably holds the vertical movement cam 81 at one end. 82, a vertical feed shaft 83 that performs a reciprocating rotation operation, a transmission arm 84 that is fixedly mounted on the vertical feed shaft 83 and performs a reciprocating rotation operation around the vertical feed shaft 83, and a vertical feed shaft 83 that is fixedly mounted. A vertical feed arm 85 that rotates around the vertical feed shaft 83, and a link body 86 that connects one end of the feed base 19 on which the feed dog 14 is mounted and the rotary end of the vertical feed arm 84. I have.

The transmission arm 84 is fixedly supported by the vertical feed shaft 83 and is oriented so that its longitudinal direction is substantially along the Z-axis direction. Further, the other end portion of the vertically moving rod 82 is connected to the rotating end portion of the transmission shaft 84. On the other hand, a reciprocating motion about the lower shaft 18 is imparted to the one end portion of the vertically moving rod 82 from the vertically moving cam 81, so that the revolving end portion of the transmission arm 84 reciprocates along the X-axis direction. Only displacement is transmitted. Then, when the rotation end portion of the transmission arm 84 performs reciprocal rotation along the X-axis direction, the vertical feed shaft 83 performs reciprocal rotation.
The vertical feed arm 85 fixedly supported at one end of the vertical feed shaft 83 is oriented so that its longitudinal direction is substantially along the X-axis direction. As a result, with the reciprocating rotation of the vertical feed shaft 83, the rotational end of the vertical feed arm 85 reciprocates along the vertical direction, and the vertical end of the feed base 19 is moved up and down via the link body 86. The reciprocating motion is given.

(Lower longitudinal feed mechanism)
The lower longitudinal feed mechanism 70 includes a longitudinal cam 71 that is a circular eccentric cam fixedly supported on the lower shaft 18, a longitudinal rod 72 that rotatably holds the longitudinal cam 71 at one end, and a reciprocating rotation. The front / rear feed shaft 73 that performs the operation, the transmission arm 74 that is fixedly mounted on the front / rear feed shaft 73 and reciprocates around the front / rear feed shaft 73, the other end of the front / rear movement rod 72, and the rotation of the transmission arm 74. A bell crank 75 that connects the moving end portion and a front / rear feed arm 76 that is fixedly mounted on the front / rear feed shaft 73 and that reciprocates around the front / rear feed shaft 73 are provided.

The transmission arm 74 is fixedly supported by the front-rear feed shaft 73 and is oriented so that its longitudinal direction is substantially along the Z-axis direction. Therefore, the rotation end portion of the transmission arm 74 performs reciprocal rotation generally along the X-axis direction.
The bell crank 75 has a first connecting point 75 a connected to the other end of the forward / rearward movement rod 72 and a second connecting point 75 b connected to the rotating end of the transmission arm 74. The third connecting point 75c of the bell crank 75 can be changed in a reciprocating direction to an arbitrary direction along the XZ plane by a feed adjusting mechanism 90 described later. As a result, when a revolving motion is performed by the longitudinal cam 71 at one end portion of the longitudinal rod 72, the first connection point 75a of the bell crank 75 performs a reciprocating movement so as to be in contact with and away from the lower shaft 18, The third connection point 75c reciprocates along a direction determined by the feed adjustment mechanism 90. Then, the second connection point 75b connected to the rotation end of the transmission arm 74 is transmitted with the same degree of motion as the X-axis direction component in the reciprocating motion of the third connection point 75c.
As a result, the longitudinal feed shaft 73 and the longitudinal feed arm 76 reciprocate at an angle adjusted by the feed adjustment mechanism 90.
The front / rear feed arm 76 is fixedly supported by the front / rear feed shaft 73 and is oriented so that its longitudinal direction is substantially along the Z-axis direction. Accordingly, the rotational end of the front / rear feed arm 76 reciprocally rotates along the X-axis direction, and the reciprocating rotation of the front / rear feed shaft 73 imparts a reciprocating motion in the front / rear direction to the feed base 19. Become.

As described above, the feed table 19 is provided with a reciprocating vertical motion at one end by the lower vertical feed mechanism 80 and a reciprocating longitudinal motion is provided at the other end by the lower longitudinal feed mechanism 70. Since the reciprocating operations of these feed mechanisms 70 and 80 both use the sewing machine motor 15 as a drive source, their cycles are the same. Accordingly, by appropriately adjusting and synthesizing the phase of the reciprocating motion each transmitted to the feed base 19 according to the orientation and posture of the members constituting the feed mechanisms 70 and 80, the feed teeth 14 mounted on the feed base 19 are combined. It is possible to impart a substantially elliptical motion that is long in the cloth feeding direction.
The feed dog 14 is arranged so that its tooth tip protrudes somewhat above the upper surface of the needle plate when passing through the upper end portion of the elliptical movement locus, and comes into contact with the workpiece on the upper surface of the needle plate from below. Feeding operation.

(Feed adjustment mechanism)
The feed adjustment mechanism 90 includes a feed adjustment motor 91 that is a pulse motor serving as a feed adjustment drive source, an output arm 92 that rotates around the output shaft of the feed adjustment motor 91, and the lower front-rear feed mechanism 70 described above. An angle piece 93 provided at a third connection point 75c of the bell crank 75, a substantially cylindrical angle adjustment body 94 having a guide groove for slidably supporting the angle piece 93, and the angle adjustment body 94 as an axis. An input arm 95 that rotates, and a link body 96 that connects the rotation end of the output arm 92 and the rotation end of the input arm 95 are provided.
The angle adjusting body 94 is formed with a somewhat arc-shaped guide groove along the radial direction thereof, and a square piece 93 is fitted into the angle adjusting body 94 so as to be able to reciprocate along the guide groove. Yes. The angle adjuster 94 is supported so that its cylindrical center line is oriented along the Y-axis direction and is rotatable about the center line by the sewing machine frame. Accordingly, when the angle adjuster 94 rotates, the direction of the guide groove changes, and the reciprocating direction of the square piece 93 is adjusted. Thereby, the movement direction of the third connecting point 75c of the bell crank 75 of the lower front / rear feed mechanism 70 is determined, and the movement amount of the feed dog 14 in the feed direction (X direction) is adjusted.
The rotation operation of the angle adjustment body 94 is given from the adjustment motor 91 via the output arm 92, the link body 96, and the input arm 95. The adjusting motor 91 is driven in accordance with a control command based on a feed amount set in the control means of the general feed sewing machine 10 (not shown).

(Upper / lower feed mechanism)
The upper longitudinal feed mechanism 40 obtains the swing drive force of the needle bar 11 and the upper feed foot 12 from the longitudinal feed shaft 73 of the lower longitudinal feed mechanism 70 described above, whereby the feed dog 14 and the upper feed foot 12 are obtained. We are trying to synchronize.
That is, the upper front / rear feed mechanism 40 includes a needle bar swing base 41 that supports the support bar 20 of the needle bar 11 and the upper feed leg 12 so as to be movable up and down, and a needle that supports the needle bar swing base 41 so as to be swingable. A bar swinging shaft 42, an output arm 43 fixedly supported at one end of the front / rear feed shaft 73, an input arm 44 fixedly supported by one end of the needle bar swinging shaft 42 and extended downward; A link body 45 that connects the rotation end of the output arm 43 and the rotation end of the input arm 44 is provided.

The needle bar swinging shaft 42 is supported by the sewing machine frame so as to be rotatable along the Y-axis direction, and the needle bar swinging base 41 is integrated with the needle bar swinging shaft 42 around the needle bar swinging shaft 42. By swinging, the upper feed leg 12 positioned at the lower end of the needle bar 11 and the lower end of the indicating bar 20 can be reciprocated along the X-axis direction (cloth feed direction).
On the other hand, the needle bar swinging shaft 42 is given reciprocating rotation from the front / rear feed shaft 73 that performs reciprocating rotation via the output arm 43, the link body 45, and the input arm 44. The foot 12 and the needle bar 11 can reciprocate along the cloth feeding direction in synchronization.

(Upper vertical feed mechanism)
The upper vertical feed mechanism 50 performs a reciprocating rotation operation with a triangular cam 61 fixedly supported by the upper shaft 16 and a vertical movement rod 62 as a cam follower that rotatably holds the triangular cam 61 at one end. A vertical feed shaft 53, a transmission arm 54 fixedly mounted on the vertical feed shaft 53 and reciprocating around the vertical feed shaft 53, and a fixed arm mounted on the vertical feed shaft 53 and reciprocating around the vertical feed shaft 53 A vertical feed arm 55 that performs a rotation operation, a bell crank 56 in which first to third connecting points 56a, 56b, and 56c are connected to the vertical feed arm 55 side, the upper feed foot 12 side, and the presser foot 13 side; A link body 57 that connects the one connection point 56a and the rotating end of the vertical feed arm 55, a link body 58 that connects the second connection point 56b and the support rod 20 that supports the upper feed leg 12, Supports the third connecting point 56c and the presser foot 13 A link member 59 which connects the Jibo 21, and a.

The triangular cam 61 and the vertically moving rod 62 have a characteristic of giving a predetermined reciprocating displacement substantially along the X-axis direction by their cooperation. These will be described in detail later.
The transmission arm 54 is arranged generally in the Z-axis direction, and as described above, when the reciprocating displacement is input from the vertical movement rod 62 to the rotating end portion along the X-axis direction, the transmission arm 54 reciprocates to the vertical feed shaft 53. Transmits rotating motion.
On the other hand, the vertical feed arm 55 is also arranged in the Z-axis direction. By the reciprocating rotation of the vertical feed shaft 53, the rotational end of the vertical feed arm 55 also reciprocates along the X-axis direction. .
The bell crank 56 has a triangular shape, and one side connecting the second connection point 56b and the third connection point 56c generally faces the X-axis direction, and the first connection point 56a is positioned above the one side. Is arranged in. In this arrangement, when an input is made to one of the reciprocating motions along the X-axis direction (second connection point 56b side) at the first connection point 56a, the bell crank 56 is moved relative to the third connection point 56c. A rotation operation for lowering the second connecting point 56b is performed, and the upper feed leg 12 is lowered. Further, when an input is made to the other side of the reciprocating motion along the X-axis direction (the third connection point 56c side), the bell crank 56 moves down the third connection point 56c with respect to the second connection point 56b. Rotating motion is performed, and the presser foot 13 is lowered. When the upper feed leg 12 (pressing foot 13) reaches the needle plate by its lowering operation, the upper feeding foot 12 (pressing foot 13) cannot be lowered any further. It will be. That is, when the upper feed leg 12 performs the lowering operation, the presser foot 13 rises accordingly. When the feed leg 13 lowers, the upper feed foot 12 rises accordingly. Is called. The reciprocating vertical movement of the upper feed leg 12 and the reciprocating vertical movement of the presser foot 13 are both performed by one stroke during one rotation of the upper shaft 16.

(Cam mechanism of the upper vertical feed mechanism)
The aforementioned triangular cam 61 and the vertical movement rod 62 constitute a cam mechanism 60. FIG. 2 is an explanatory view showing the outer shape of the triangular cam 61 in detail, and FIG. 3 is a configuration diagram of the cam mechanism 60 as viewed from the surface side of the sewing machine 10.
The triangular cam 61 has an outer peripheral shape formed by connecting two kinds of large and small arcs centered on each of the three vertices of the regular triangle, and a peripheral surface formed along the outer peripheral shape is a cam surface. That is, the triangular cam 61 has a circular arc that is a fan-shaped outer edge with a radius R including the entire area of the regular triangle centered on one vertex of the regular triangle and a central angle of 60 °, and just the large arc A. A circular arc (small arc a) having a radius r formed on the opposite side and a central angle of 60 ° is formed at each vertex, and has an outer peripheral shape in which the ends of the large arc and the small arc are alternately connected. The radius R of the large arc A, the radius r of the small arc a, and the length T of one side of the equilateral triangle are such that R = r + T.
With this outer peripheral shape, the triangular cam 61 always has a width of r + R in a straight line passing through the apex.
Conventional general triangular cams have the above-mentioned outer diameter and rotate around any vertex of a regular triangle. On the other hand, the triangular cam 61 applied to the sewing machine 10 of the present invention has a rotation center S at a position on the perpendicular P extending from any one vertex to the corresponding base and beyond the center point C of the equilateral triangle. In addition, in order to distinguish the base on which the perpendicular line P is lowered from the other two bases, it is referred to as “base U”. In addition, by setting the rotation center S of the triangular cam 61 as described above, the base U is positioned closest to the rotation center S compared to the other two bases.

Further, since the triangular cam 61 is fixedly supported on the upper shaft 16, the rotation is given in complete synchronization with the vertical movement of the needle bar 11. That is, the triangular cam 61 also makes one rotation with one stroke of the needle bar 11. Further, the triangular cam 61 is fixedly mounted on the upper shaft 16 so that the top dead center of the reciprocating vertical movement applied to the upper feed leg 12 is in a phase that coincides with the needle bar top dead center.
As a result, when the needle bar 11 is positioned at its top dead center, the bottom U of the triangular cam 61 is in a state along the vertical vertical direction.

The vertically moving rod 62 is engaged with the triangular cam 61 at the other end portion of the flange portion 63 whose one end portion is rotatably connected to the rotation end portion of the transmission arm 54 via a step screw 69. And an engaging portion 64 to be joined.
The engaging portion 64 is formed in an annular shape with a square opening formed on the inner side, the length of one side of the inner square is set to r + R, and engages the state in which the triangular cam 61 is accommodated inside. It has become. The pair of cam receiving surfaces 65 and 66 along two opposite sides of the square are parallel to each other, and further in a direction parallel to the vertical feed shaft 53 and to be applied to the transmission arm 54. The direction perpendicular to the direction (here, the direction perpendicular to the longitudinal direction of the flange 63) is set, and the receiving surfaces 65 and 66 are reciprocated to the transmission arm 54 and the vertical feed shaft 53 by the displacement received from the triangular cam 61. Giving rotation. Further, the displacement received by the receiving surfaces 67 and 68 is absorbed by the vertical movement rod 62 being rotated around the step screw 69, and hardly transmitted as displacement to the transmission arm 54 side.

Next, the relationship between the displacement and speed along the X-axis direction transmitted to the transmission arm 54 by the cam receiving surfaces 65 and 66 of the triangular cam 61 and the vertical movement rod 62 and the rotational center position of the triangular cam 61 described above is detailed. Explained.
FIG. 4 is an explanatory view showing the displacement in the X-axis direction that occurs in the engaging portion 64 of the vertical movement rod 62 as the triangular cam 61 rotates. The description will be made on the assumption that the triangular cam 61 rotates clockwise with the state of FIG. As described above, the upper feed leg 12 and the needle bar 11 are at the top dead center position at 0 ° in FIG. Further, since the 90 ° displacement in FIG. 4 is the center of the amplitude, the position is described as displacement 0. Also, since the displacement in the Z direction has little effect on the displacement in the X direction,
For ease of explanation, the following formula shows the displacement in the Z direction as zero.
When the shaft angle of the vertical feed shaft 16 is θ and the displacement in the X-axis direction is f (θ), the triangular cam 61 is
F (θ) =-0.5Tk ・ T ・ sin (θ- (π / 2)) in the range of 0 to 30 °
F (θ) = 0.5T-Tcos (θ- (π / 6))-k ・ T ・ sin (θ- (π / 2))
F (θ) =-0.5T + Tcos (θ- (5π / 6))-k ・ T ・ sin (θ- (π / 2))
F (θ) = 0.5Tk ・ T ・ sin (θ- (π / 2)) in the interval of 150 to 210 °
F (θ) =-0.5T + Tcos (θ- (7π / 6))-k ・ T ・ sin (θ- (π / 2))
F (θ) = 0.5T + Tcos (θ- (5π / 6))-k ・ T ・ sin (θ- (π / 2))
F (θ) =-0.5Tk ・ T ・ sin (θ- (π / 2)) in the range of 330 to 360 °
The position displacement is shown. In each equation, k is the ratio of the distance from the apex of the equilateral triangle to the rotation center S when the length T of one side of the equilateral triangle is 1.
Furthermore, the speed f ′ (θ) in each section is
F '(θ) =-k ・ T ・ cos (θ- (π / 2)) in the range of 0 to 30 °
F '(θ) = Tsin (θ- (π / 6))-k ・ T ・ cos (θ- (π / 2))
F '(θ) =-Tsin (θ- (5π / 6))-k ・ T ・ cos (θ- (π / 2)) for 90 to 150 °
F '(θ) =-k ・ T ・ cos (θ- (π / 2)) in the interval of 150 to 210 °
F '(θ) =-Tsin (θ- (7π / 6))-k ・ T ・ cos (θ- (π / 2))
F '(θ) =-Tsin (θ- (5π / 6))-k ・ T ・ cos (θ- (π / 2))
F '(θ) =-k ・ T ・ cos (θ- (π / 2)) in the range of 330 to 360 °
It becomes.

Here, the relationship between the change in the center position of the triangular cam 61 by the coefficient k and the positional displacement D and velocity displacement V is shown in FIGS. The diagrams of the position displacement D and the speed displacement V in FIGS. 5 to 8 show the position f (θ) and the speed f ′ (θ) described above continuously connected in the entire section of 0 to 360 °. is there. A point G in the figure indicates a landing point of the upper feed leg 12. Here, the landing point G is set to an intermediate position in the vertical amplitude.
5 shows a case where k = 0.7, FIG. 6 shows a case where k = 0.8, FIG. 7 shows a case where k = 0.866, FIG. 8 shows a case where k = 0.9, and FIG. 9 shows a case where k = 1.0. The value of k = 0.866 in FIG. 7 is the case where the rotation center S of the triangular cam 61 is set at the intersection of the perpendicular and the base U. At this time, the upper feed leg 12 is at the velocity V = 0 in the phase of the landing point G. It turns out that it becomes. Further, it can be seen that even when k = 0.7 to 1.0 where the rotation center is in the vicinity thereof, the landing is performed at a speed that is less than half of the maximum speed of ascent or descent in the phase of the landing point G. That is, it can be seen that the speed can be sufficiently reduced when the upper feed leg 12 is landed.

(Operation of general feed sewing machine)
In the integrated feed sewing machine 10 having the above-described configuration, the needle vertical movement mechanism 30 imparts a vertical movement to the needle bar 11 by driving the sewing machine motor 15. Then, an ellipse motion is imparted to the feed dog 14 by the cooperation of the lower front / rear feed mechanism 70 and the lower vertical feed mechanism 80, and a feed operation from below the workpiece is executed.
Further, the upper feed leg 12 and the presser foot 13 are alternately moved up and down by the upper vertical feed mechanism 50 and the upper feed leg 12 is moved up and down together with the needle bar 11.
Further, a swinging motion is applied from the front / rear feed shaft 73 of the lower front / rear feed mechanism 70, and the upper front / rear feed mechanism 40 imparts a swing motion in the front / rear direction to the needle bar 11 and the upper feed foot 12. At this time, the lower front / rear feed mechanism 70 swings backward when the needle bar 11 and the upper feed leg 12 are raised, and swings forward when the needle bar 11 and the upper feed leg 12 are lowered. . As a result, when the sewing needle is stuck in the sewing product, the upper feed leg 12 feeds, and even a heavy sewing material or thick material can be effectively fed. Further, the feed by the upper feed leg 12 and the feed by the feed dog 14 are performed simultaneously in the forward feed operation, and effective feed can be realized from this action.
Further, since the upper vertical feed mechanism 50 includes the cam mechanism 60 described above, when the upper feed leg 12 is lowered from the top dead center to the bottom dead center, the lowering speed is temporarily reduced to 0 at the intermediate point. ,
The impact of landing on the upper feed leg 12 is reduced.

(Effect of general feed sewing machine)
As described above, in the cam mechanism 60 of the total feed sewing machine 10, the vertical movement rod 62 is displaced by the receiving surfaces 65 and 66 with respect to the triangular cam 61 whose rotation center is offset, and the reciprocating operation is taken out. The triangular cam 61 has a characteristic that the position displacement in the fixed reciprocating direction (here, the X-axis direction) greatly decelerates at a substantially intermediate position from one maximum displacement to the other maximum displacement. Thus, this is converted into a reciprocating rotation operation, transmitted to the vertical feed shaft 53, and applied to the application of the vertical movement of the upper feed foot 12, so that the middle from the top dead center to the bottom dead center of the upper feed foot 12 is achieved. It is possible to decelerate at the position of, and it is possible to avoid the situation where the descending speed becomes the fastest when the upper feed leg 12 lands, and the impact is reduced by the low speed landing and the durability of the mechanism is improved. In addition, it is possible to avoid smashing the workpiece. Accordingly, it is possible to avoid an increase in production cost due to the strengthening of the upper feed leg.
In particular, in the general feed sewing machine 10, since the rotation center of the triangular cam 61 is set at the intersection S of the perpendicular line P and the base U, which is lowered from the apex of the regular triangle, the speed at the intermediate point between the two phases generating the maximum amplitude. Can be set to 0, and by adjusting the intermediate point so as to coincide with the landing point of the upper feed leg 12 on the needle plate, the descending speed of the upper feed leg 12 upon landing can be substantially zero. Thus, the durability of the mechanism can be improved more effectively, the workpiece can be protected, and the cost can be reduced.

(Second embodiment)
Another example of the cam mechanism will be described with reference to FIG.
The cam mechanism 60A includes the same triangular cam 61 as described above, a bifurcated vertical movement rod 62A, and a link body 67A that transmits the swinging motion applied from the triangular cam 61 to the vertical movement rod 62A to the transmission arm 54. It has.
The vertically moving rod 62A includes a collar portion 63A whose one end is pivotally supported in the sewing machine frame by a support shaft 69A, and an engaging portion 64A that engages with the triangular cam 61 at the other end of the collar portion 63A. . The engaging portion 64A includes a pair of cam receiving surfaces 65A and 66A that are in contact with the outer periphery so as to sandwich the triangular cam 61 therebetween. These cam receiving surfaces 65A and 66A are planes parallel to the flange portion 63A, and thereby, the vertical movement rod 62A can be rotated around the support shaft 69A. Unlike the above-described vertical movement rod 62, the vertical movement rod 62A is disposed substantially along the Z-axis direction. Then, the swinging motion generated in the engaging portion 64A of the vertically moving rod 62A is applied to the rotating end portion of the transmission arm 54 by the link body 67A.
Also in this case, the triangular cam 61 is fixedly mounted on the upper shaft 16 by adjusting the phase so that the top dead center of the upper feed leg 12 and the top dead center of the needle bar 11 coincide with each other. At the dead point, the bottom U of the triangular cam 61 is in a state of facing vertically up and down.
By incorporating the cam mechanism 60A into the total feed sewing machine 10 in place of the cam mechanism 60, the same effect as that of the total feed sewing machine 10 described above can be obtained.

(Third embodiment)
Another example of the cam mechanism will be described with reference to FIG.
The cam mechanism 60B includes the same triangular cam 61 as in the first embodiment, the same bifurcated vertical movement rod 62A as in the second embodiment, and a link body 67B. The cam mechanism 60B and the transmission arm 54 are provided. And constitutes a four-bar linkage mechanism.
The vertical movement rod 62 </ b> A connects one end portion of the flange portion 63 </ b> A to the rotating end portion of the transmission arm 54 with a step screw 69 in a state substantially along the X-axis direction.
One end of the link body 67B is rotatably connected to the sewing machine frame by a support shaft 68B, and the other end is connected to the engaging portion 64A of the vertically moving rod 62A via a step screw 66B. Thus, the swinging motion is applied to the engaging portion 64A of the vertical movement rod 62A by the triangular cam 61 in a direction perpendicular to the longitudinal direction of the vertical movement rod 62A. The swinging motion direction does not coincide with the direction in which the reciprocating motion is imparted to the transmission arm 54. However, as a result of the movement motion locus being restricted by the link body 67B on the engaging portion 64A side of the vertical motion rod 62A, the vertical motion is increased. The reciprocating movement is also performed in the longitudinal direction of the moving rod 62A, so that the reciprocating rotation can be given to the transmission arm 54.
Also in this case, the triangular cam 61 is fixedly mounted on the upper shaft 16 by adjusting the phase so that the top dead center of the upper feed leg 12 and the top dead center of the needle bar 11 coincide. However, in this example, at the top dead center of the needle bar, as shown in FIG. 11, the bottom U of the triangular cam 61 is in a state of facing the horizontal direction.
Therefore, by replacing the cam mechanism 60B with the cam mechanism 60 and incorporating the cam mechanism 60B into the total feed sewing machine 10, it is possible to obtain the same effect as that of the total feed sewing machine 10 described above.

(Fourth embodiment)
Another example of the cam mechanism will be described with reference to FIGS.
This cam mechanism 60C has the same outer peripheral shape as the triangular cam 61 described above and a triangular cam 61C fixedly supported on the upper shaft 16 so that the rotation center position coincides with one of the apexes of the regular triangle, and a triangular cam at one end. And a vertical movement rod 62C that rotatably holds the cam 61C.
The vertical movement rod 62C includes a flange 63C having one end rotatably connected to the rotation end of the transmission arm 54 via a step screw 69, and a triangular cam 61C at the other end of the flange 63C. And an engaging portion 64 </ b> C that engages.
The engaging portion 64C is formed in an annular shape with a square opening formed on the inner side, the length of one side of the inner square is set to r + R, and engages the state in which the triangular cam 61C is accommodated inside. It has become. The pair of cam receiving surfaces 65C and 66C along the two opposite sides of the square are parallel to each other and further in a direction parallel to the vertical feed shaft 53, and should be applied to the transmission arm 54. The direction (here, the direction orthogonal to the longitudinal direction of the flange 63C) is inclined at 45 °. Further, another set of cam receiving surfaces 67C and 68C along two opposite sides of the square is parallel to each other, and is in a direction parallel to the vertical feed shaft 53 and should be provided to the transmission arm 54. It is inclined at 45 ° in the operating direction (here, the direction orthogonal to the longitudinal direction of the flange 63C) and is orthogonal to the cam receiving surfaces 65C and 66C described above. As a result, the vertical movement rod 62C is given a displacement in the longitudinal direction, which is a combination of the displacements received by the two sets of receiving surfaces 65C, 66C and 67C, 68C from the triangular cam 61C.

  The triangular cam 61C is also fixedly mounted on the upper shaft 16 with its phase adjusted so that the top dead center of the upper feed leg 12 and the top dead center of the needle bar 11 coincide. Further, the base U farthest from the rotation center of the triangular cam 61C (in this example, the base farthest away from the base closest to the rotation center) is the vertical direction at the needle bar top dead center as shown in FIG. It is in a state of facing. Further, at this needle bar top dead center, the four cam receiving surfaces 65C, 66C, 67C, 68C are inclined at approximately 45 ° with respect to the reciprocating direction of the vertical movement rod 62C when viewed from the Y-axis direction. It has become. In addition, it is desirable that the inclination angle of each cam receiving surface 65C, 66C, 67C, 68C is within a range of 40 to 50 °.

FIG. 13 shows a positional displacement D and a velocity displacement V by the cam mechanism 60C. As shown in the figure, the cam mechanism 60C has a period during which the speed is reduced while shifting from the maximum amplitude to one side to the maximum amplitude to the other side. That is, when the cam mechanism 60C is used for the vertical movement of the upper feed leg 12, it is possible to decelerate midway from the top dead center to the bottom dead center, and to decelerate at the time of landing.
Therefore, by incorporating the cam mechanism 60C in the total feed sewing machine 10 in place of the cam mechanism 60, it is possible to obtain the same effect as the total feed sewing machine 10 described above.
In this embodiment, the triangular cam is fixedly supported on the upper shaft 16, but may be fixed to another shaft as long as it is a shaft that rotates once with respect to one up-and-down movement of the needle bar 11. Needless to say, other mechanisms can be changed as long as they do not depart from the spirit of the present invention.

10 General feed sewing machine (vertical feed sewing machine)
12 Upper feed leg 14 Feed dog 16 Upper shaft (rotary shaft)
40 Upper-side longitudinal feed mechanism 50 Upper-side vertical feed mechanism 60, 60A, 60B, 60C Cam mechanism 61, 61C Triangular cam 62, 62A, 62C Vertical movement rod (cam follower)
65, 65A, 65C Cam receiving surface 66, 66A, 66C Cam receiving surface 67, 67C Cam receiving surface 68, 68C Cam receiving surface 70 Lower longitudinal feed mechanism 80 Lower vertical feed mechanism

Claims (7)

A feed dog that performs feed operation by contacting the workpiece on the needle plate from below;
An upper feed leg for performing a feed operation in contact with an article to be sewn on the needle plate from above;
A lower back-and-forth feed mechanism that gives the feed dog a reciprocating motion along the feed direction;
A lower vertical feed mechanism that imparts a reciprocating motion along the vertical direction to the feed dog;
An upper back-and-forth feed mechanism that imparts a reciprocating motion along the feed direction to the upper feed leg;
An upper vertical feed mechanism that imparts a reciprocating motion along the vertical direction to the upper feed leg,
In a vertical feed sewing machine that feeds the workpiece by cooperation of the feed dog and the upper feed leg,
The upper vertical feed mechanism includes a cam mechanism that takes out a reciprocating operation from a rotating operation of a rotating shaft that performs rotational driving,
The cam mechanism includes an outer peripheral triangular cam having two large and small arcs centered on three vertices of an equilateral triangle, and at least one pair of receiving members facing each other so as to sandwich the triangular cam. A cam follower having a surface,
The triangular cam is fixed to the rotating shaft so as to rotate about a position on the base side from the center point of the equilateral triangle, which is on a vertical line descending from one of the vertices toward the base. Supported,
The vertical feed is characterized in that the triangular cam is fixedly supported on the rotary shaft so that the top dead center of the upper feed leg and the top dead center of the needle bar which is sewn by the vertical movement coincide with each other. sewing machine.   The base of the triangular cam closest to the rotating shaft is fixedly supported by the rotating shaft so that the bottom side of the triangular cam is directed vertically or horizontally at the top dead center of the needle bar. Vertical feed sewing machine.   3. The vertical feed according to claim 1, wherein the triangular cam has a distance from the vertex to the rotation center of 0.7 or more and 1.0 or less when the length of one side of the regular triangle is 1. sewing machine.   The vertical feed sewing machine according to claim 3, wherein the triangular cam has the position of the rotation center as an intersection of the perpendicular and the bottom with respect to the apex. A feed dog that performs feed operation by contacting the workpiece on the needle plate from below;
An upper feed leg for performing a feed operation in contact with an article to be sewn on the needle plate from above;
A lower back-and-forth feed mechanism that gives the feed dog a reciprocating motion along the feed direction;
A lower vertical feed mechanism that imparts a reciprocating motion along the vertical direction to the feed dog;
An upper back-and-forth feed mechanism that imparts a reciprocating motion along the feed direction to the upper feed leg;
An upper vertical feed mechanism that imparts a reciprocating motion along the vertical direction to the upper feed leg,
In a vertical feed sewing machine that feeds the workpiece by cooperation of the feed dog and the upper feed leg,
The upper vertical feed mechanism includes a cam mechanism that takes out a reciprocating operation from a rotating operation of a rotating shaft that performs rotational driving,
The cam mechanism includes a triangular cam having an outer peripheral shape in which two types of arcs centered on three vertices of an equilateral triangle are connected, and at least two sets of receiving members facing each other so as to sandwich the triangular cam. A cam follower having a surface,
The triangular cam is fixedly supported on the rotating shaft so as to rotate around any one of the vertices,
The follower body reciprocates by a combined displacement of the displacements received by the two sets of receiving surfaces,
The vertical feed is characterized in that the triangular cam is fixedly supported on the rotary shaft so that the top dead center of the upper feed leg and the top dead center of the needle bar which is sewn by the vertical movement coincide with each other. sewing machine. The base farthest from the apex located at the center of rotation of the triangular cam is fixedly supported on the rotary shaft so as to face the vertical direction at the top dead center of the needle bar, and
The two sets of receiving surfaces parallel to each other of the cam follower are inclined at a top dead center of the needle bar in a range of 40 to 50 ° with respect to the reciprocating direction. 5. The vertical feed sewing machine according to 5.   The vertical feed sewing machine according to claim 5 or 6, wherein two sets of receiving surfaces parallel to each other of the cam follower are inclined at 45 ° with respect to the reciprocating direction.

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