JP4952701B2 - Spring unit - Google Patents

Description

  The present invention relates to a spring unit including a damper that reduces the extension speed of a spring.

  There is a device that moves an object using the elastic force of a spring. For example, a press die has a lifter supported by a spring. The lifter is attached to the lower mold, and is pressed by the upper mold with the work placed. The spring is compressed and deformed by the pressing force of the upper die. When the upper die is raised and separated from the lifter, the spring is extended and the lifter is raised. The lifter stops rising when it comes into contact with the stopper. If the lift of the lifter stops abruptly, there is a possibility that the workpiece placed on the lifter falls from the lifter. Therefore, for example, Patent Document 1 discloses a technique for reducing the extension speed of the spring near the lifted end of the lifter.

  Patent Document 1 discloses a spring unit having a damper. In this spring unit, a damper is attached to the upper end of the spring. When the spring is extended from the compressed state, the damper attached to the upper end of the spring comes into contact with the contact member. Thereafter, the damper is compressed in the extension direction of the spring, whereby the extension rate of the spring is reduced. As a result, the lifting speed of the lifter is reduced. This prevents the lifter from stopping suddenly. Thereby, it can suppress that a workpiece | work falls from a lifter.

Japanese Utility Model Publication No. 2-114140

  In the press mold, the maximum allowable dimension of the mold is determined by the equipment. It is desirable to make the mold dimensions as small as possible. It is desirable that the spring unit for moving the lifter be as small as possible.

  The present invention was created in view of the above-described circumstances, and provides a technique for downsizing a spring unit including a damper that reduces the extension speed of the spring.

  In order to solve the above-described problems, a spring unit including a damper that reduces the extension speed of the spring is provided. The spring unit includes a spring, a first member, and a second member. The 1st member has the 1st spring seat, the 1st stroke part, and the 1st contact part. The first spring seat abuts on one end of the spring and receives a spring force. The first stroke portion extends from the first spring seat to the inside of the spring in the extension direction of the spring. The first contact portion is fixed to the first stroke portion. The 2nd member has the 2nd spring seat, the 2nd stroke part, and the 2nd contact part. The second spring seat abuts on the other end of the spring and receives a spring force. The second stroke portion extends from the second spring seat to the inside of the spring in the extension direction of the spring, and the tip thereof reaches the first spring seat side with respect to the first contact portion. The 2nd contact part is being fixed to the 2nd stroke part of the range extended to the 1st spring seat side rather than the 1st contact part. At least one of the first stroke portion and the first contact portion has a damper that consumes energy to change the length of the spring in the extending direction. The damper may be, for example, an oil-type or air-type shock absorber that strokes in the extension direction of the spring, or may be an elastic body such as rubber or sponge that can be elastically deformed in the extension direction of the spring. Further, the first contact portion itself may be a damper. The axial center of the spring satisfies the positional relationship passing through the first contact portion, the second contact portion, and the damper. When the first contact portion itself is a damper, the axial center of the spring satisfies the positional relationship passing through the second contact portion and the damper.

  In this spring unit, when the spring extends, the first contact portion and the second contact portion come into contact. At this time, the length of the damper arranged in the first stroke part or the first contact part changes in the extension direction of the spring by consuming the energy of extension of the spring. As a result, the extension speed of the spring is reduced. In this spring unit, the damper is disposed inside the spring. According to this configuration, the overall length of the spring unit can be made substantially equal to the length of the spring. That is, the above configuration can make the spring unit smaller than the conventional one.

  In this spring unit, the first member and the second member are preferably rotationally symmetric with respect to the axis of the spring. According to such a configuration, the force of the damper can be applied to the spring in a balanced manner.

In this spring unit, the first stroke portion is preferably cylindrical. It is preferable that the second stroke portion is cylindrical and the first stroke portion is inserted. It is preferable that the damper is disposed at the first contact portion. It is preferable that a part of the side wall of the first stroke portion is formed with a pair of slits extending in the extension direction of the spring and facing each other. It is preferable that the second contact portion is inserted through the pair of slits and both ends thereof are supported by the second stroke portion.
According to such a configuration, the first stroke portion slides in the cylindrical second stroke portion. From this, it can prevent that a 1st stroke part and a 2nd stroke part shift | deviate to the direction which cross | intersects a slide direction relatively. That is, it is possible to prevent the positional relationship between the first contact portion, the second contact portion, and the damper from shifting.

  In this spring unit, it is preferable that at least one of the first member and the second member is attached with a spring seat and a stroke portion in a detachable manner. It is preferable that a pair of through-holes facing each other is formed in the second stroke portion. It is preferable that the second contact portion is inserted and supported through the pair of through holes. With such a configuration, the spring unit can be easily disassembled and assembled. Assembly can be performed by the following procedure. First, the first stroke part to which the damper is attached is inserted into the second stroke part. A 2nd contact part is inserted from one through-hole of a 2nd stroke part, a pair of slit of a 1st stroke part is passed, and it inserts in the other through-hole of a 2nd stroke part. The first stroke portion and the second stroke portion are inserted into the spring. The removed spring seat is attached to the stroke part. The spring unit can be completed by the above procedure. When disassembling the spring unit, the above procedure may be reversed. Such a spring unit can facilitate parts replacement and maintenance.

  According to the present invention, it is possible to reduce the size of a spring unit including a damper that decelerates the extension speed of the spring during the extension of the spring. By using the spring unit of the present invention for the lifter of the mold, it is possible to prevent the workpiece from slipping off the lifter without increasing the size of the mold.

Here, a part of preferred embodiments in the technology described in this specification are listed.
(Mode 1) The first stroke portion may be cylindrical. The 2nd stroke part is cylindrical and may be inserted in the 1st stroke part. The damper may be fixed to a support portion supported by the first stroke portion. A pair of slits extending in the extension direction of the spring and facing each other may be formed in a part of the side wall of the second stroke portion. The support part may be inserted into the pair of slits and both ends thereof may be supported by the first stroke part.
Also with the above configuration, it is possible to reduce the size of the spring unit including a damper that reduces the extension speed of the spring during the extension of the spring.
(Mode 2) The first contact portion and the second contact portion are separated from each other when the spring is most compressed. After the first contact portion and the second contact portion contact, the damper starts to shrink along the longitudinal direction of the spring. The first abutting portion and the second abutting portion abut on each other from the middle of extension of the spring to the most extended state. The same applies when the first contact portion is a damper. As a result, the length of the damper in the extension direction of the spring changes from the middle of extension of the spring to the most extended state. As a result, the extension speed of the spring is reduced.

(First embodiment)
A spring unit according to an embodiment embodying the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a mold 10 having a spring unit 30. The mold 10 is attached to a press device (not shown). In FIG. 1, the spring unit 30 is depicted in a simplified manner. The spring unit 30 will be described in detail later. The mold 10 is divided into an upper mold 12 and a lower mold 22. In the press working apparatus, when the upper die 12 is lowered, the upper die 12 and the lower die 22 are combined to machine the workpiece 50.

  The upper die 12 is fixed to a ram (not shown) of a press working apparatus (not shown). The upper mold 12 includes a pad 20, a cutting edge 16, and a lifter pressing portion 14. The pad 20 is supported on the upper mold 12 via a coil spring 18. The length of the pad 20 in the longitudinal direction (showing a direction perpendicular to the drawing in FIG. 1 is referred to as “longitudinal direction” hereinafter) is substantially the same as the length of the workpiece 50 in the longitudinal direction. have. The cutting blades 16 are disposed on both sides of the pad 20 (on the left and right sides in FIG. 1, and in the following, both sides mean the left and right sides in the drawing). The length of the cutting edge 16 in the longitudinal direction is substantially the same as the length of the workpiece 50 in the longitudinal direction. The cutting edge 16 is fixed to the upper mold 12. The lifter pressing portions 14 are formed on both sides of the upper mold 12.

  The lower die 22 is fixed to a bolster (not shown) of a press working apparatus (not shown). The lower mold 22 includes a punch (not shown), a lifter 24 and a base 28. The base 28 is fixed to the bolster. The punch is fixed to the base 28. The punch is disposed at a position facing the pad 20. The punch is divided into three parts intermittently in the longitudinal direction. A space is provided between each portion of the punch. A lifter 24 is disposed between the portions of the punch. That is, two lifters 24 are arranged at intervals along the longitudinal direction of the punch. The lifter 24 is supported by the base 28 via the spring unit 30. The lifter 24 is pressed upward by the spring unit 30. The lifter 24 is restricted from moving upward by the stopper 25. The stopper 25 is fixed to the base 28. The length obtained by adding the length in the longitudinal direction of each part of the punch and the length in the longitudinal direction of the two lifters 24 is substantially the same as the length in the longitudinal direction of the pad 20. The lifter 24 includes a pressure receiving portion 26 at a position facing the lifter pressing portion 14.

  When the upper mold 12 is lowered with respect to the lower mold 22, the lifter pressing portion 14 comes into contact with the pressure receiving portion 26 of the lifter 24 and pushes down the lifter 24. When the lifter 24 is lowered, it is separated from the stopper 25. When the upper mold 12 is lowered to the bottom dead center, the upper mold 12 starts to rise with respect to the lower mold 22. When the upper die 12 is raised, the downward load applied to the lifter 24 by the lifter pressing portion 14 is unloaded. The lifter 24 is moved upward by the coil spring unit 30. When the lifter 24 is lifted, it comes into contact with the stopper 25 and the lift of the lifter 24 is stopped.

  FIG. 2 is a longitudinal sectional view of the spring unit 30. FIG. 2 shows a state where the pressure receiving portion 26 is not pressed by the lifter pressing portion 14. That is, FIG. 2 shows a state in which the coil spring 38 is most extended. The spring unit 30 includes a coil spring 38, a first tubular member 31, and a second tubular member 46. The first tubular member 31 includes a first spring seat 32, a first tubular stroke portion 36, and a shock absorber 40. The first spring seat 32 has a disk shape having a through hole at the center. The diameter of the first spring seat 32 is substantially the same as the outer diameter of the coil spring 38. The first spring seat 32 is in contact with the upper end of the coil spring 38 and receives the spring force of the coil spring 38. The first cylindrical stroke portion 36 is fixed by the first spring seat 32 and the bolt 34. The first cylindrical stroke part 36 has a cylindrical shape. The 1st spring seat 32 and the 1st cylindrical stroke part 36 are arrange | positioned coaxially. The outer diameter of the first cylindrical stroke portion 36 is slightly smaller than the inner diameter of the second cylindrical stroke portion 42 described later. In the first cylindrical member 31, the first cylindrical stroke portion 36 is inserted inside the coil spring 38, and a part of the lower end of the first cylindrical member 31 is inserted into the second cylindrical stroke portion 42. Yes. A shock absorber 40 is fitted to the lower end of the first cylindrical stroke portion 36. The shock absorber 40 is an oil type shock absorber. An axial center 38 a of the coil spring 38 passes through the center of the shock absorber 40. A pair of long holes 36 a (see FIG. 3) is formed in the first cylindrical stroke portion 36 symmetrically with respect to the center of the first cylindrical stroke portion 36. The first cylindrical member 31 is disposed rotationally symmetrically with respect to the axis 38a. In this specification, the long hole 36a means one type of slit.

  The second cylindrical member 46 includes a second spring seat 48, a second cylindrical stroke portion 42, and a contact member 44. The second spring seat 48 has a disk shape having a through hole at the center. The diameter of the second spring seat 48 is substantially the same as the outer diameter of the coil spring 38. The second spring seat 48 contacts the lower end of the coil spring 38 and receives the spring force of the coil spring 38. The second cylindrical stroke portion 42 is erected vertically from the second spring seat 48. The second cylindrical stroke part 42 has a cylindrical shape. The 2nd spring seat 48 and the 2nd cylindrical stroke part 42 are arrange | positioned coaxially. The outer diameter of the second cylindrical stroke portion 42 is slightly smaller than the inner diameter of the coil spring 38. The second spring seat 48 and the second cylindrical stroke portion 42 are integrally formed. In the second cylindrical member 46, the second cylindrical stroke portion 42 is inserted inside the coil spring 38, and the second spring seat 48 contacts the lower end of the coil spring 38. In the second cylindrical stroke portion 42, a pair of through holes 42a are formed near the upper end thereof (see FIG. 3). The pair of through holes 42 a are formed symmetrically with respect to the center of the second cylindrical stroke portion 42. The contact member 44 passes through the pair of long holes 36a of the first cylindrical stroke portion 36 from one through hole 42a and is inserted into the other through hole 42a. Both ends of the contact member 44 are supported by the second cylindrical stroke portion 42. The contact member 44 passes through the center of the second cylindrical stroke portion 42. The axis 38 a of the coil spring 38 passes through the center of the contact member 44. The shape of the second cylindrical member 46 is rotationally symmetric with respect to the axis 38a.

  FIG. 3 is an exploded perspective view for explaining an assembly method of the spring unit 30. The assembly procedure of the spring unit 30 will be described with reference to FIG. A shock absorber 40 is fitted to the lower end of the first cylindrical stroke portion 36. The first cylindrical stroke portion 36 is inserted into the second cylindrical stroke portion 42 so that the long hole 36a faces the through hole 42a of the second cylindrical stroke portion 42. The contact member 44 is inserted from one through hole 42a, passed through the pair of long holes 36a, and inserted into the other through hole 42a. The second cylindrical stroke portion 42 is inserted into the coil spring 38 and the second spring seat 48 is brought into contact with the coil spring 38. The first spring seat 32 is brought into contact with the upper end of the first cylindrical stroke portion 36, and the first cylindrical stroke portion 36 and the first spring seat 32 are fastened with the bolts 34, whereby the spring unit 30 is completed.

  4 to 6 are longitudinal sectional views of the spring unit 30 for explaining the operation of the spring unit 30. FIG. 4 to 6 show the spring unit 30 in a cross section orthogonal to the cross section of FIG. FIG. 4 shows a state where the upper mold 12 is located at the bottom dead center, that is, a state where the coil spring 38 is most compressed. FIG. 6 shows a state in which the coil spring 38 is most extended. FIG. 5 shows an intermediate state between the state of FIG. 4 and the state of FIG.

  As shown in FIG. 4, when the coil spring 38 is most compressed, the shock absorber 40 is positioned away from the contact member 44. In the state of FIG. 4, the lifter 24 is pushed down by the lifter pressing portion 14. The lifter 24 is separated from the stopper 25. If the upper mold | type 12 raises from the state of FIG. 4, the lifter press part 14 will raise with it. When the downward load applied to the lifter 24 by the lifter pressing portion 14 is unloaded, the coil spring 38 extends. As the coil spring 38 extends, the lifter 24 rises. Further, as the coil spring 38 extends, the first cylindrical member 31 rises. At this time, since the second cylindrical member 46 is in contact with the lower end of the coil spring 38, the position does not change. As the first cylindrical member 31 rises, the shock absorber 40 moves in a direction approaching the contact member 44.

  As shown in FIG. 5, the shock absorber 40 abuts against the abutting member 44 at a position before the coil spring 38 extends to the maximum. When the coil spring 38 is further extended from the state of FIG. 5, the shock absorber 40 is compressed. The shock absorber 40 consumes energy when the coil spring 38 extends, and the length of the coil spring 38 in the extending direction is shortened. Thereby, the extension speed of the coil spring 38 is decelerated. In the state shown in FIG. 6, the lifter 24 is brought into contact with the stopper 25 and the lift of the lifter 24 is stopped. The extension of the coil spring 38 is stopped in the state shown in FIG. As shown in FIG. 6, when the coil spring 38 is extended most, the shock absorber 40 and the contact member 44 are in contact with each other.

In the spring unit 30, the shock absorber 40 and the contact member 44 come into contact with each other while the coil spring 38 is extended from the most compressed state. As a result, the extension speed of the coil spring 38 is reduced. As a result, the lifting speed of the lifter 24 is reduced. The spring unit 30 can prevent the workpiece 50 placed on the lifter 24 from slipping off the lifter 24 even when the lifter 24 comes into contact with the stopper 25 and the lift of the lifter 24 is stopped.
FIG. 7 is a graph showing the relationship between the extension speed and extension of the coil spring 38. The horizontal axis indicates the extension of the coil spring 38 from the state in which the coil spring 38 is most compressed by the lifter pressing portion 14. The vertical axis indicates the extension speed of the coil spring 38. A solid line 52 indicates a change in the extension speed of the coil spring 38 in the spring unit 30. A broken line 54 indicates a change in the extension speed of the coil spring 38 when the shock absorber 40 is removed. According to the graph of FIG. 7, in the spring unit 30, the extension speed of the coil spring 38 is decelerated during the extension of the coil spring 38 as compared with the case without the shock absorber 40.

The features and advantages of the spring unit 30 will be described. In the spring unit 30, the shock absorber 40 and the contact member 44 are disposed inside the coil spring 38. Thereby, the spring unit 30 can be reduced in size. More specifically, in the spring unit 30, the outer diameter is substantially the same as the outer diameter of the coil spring 38, and the length thereof is the sum of the first spring seat 32 and the second spring seat 48 added to the coil spring 38. Length. For this reason, the coil spring arranged alone in the existing equipment can be easily replaced with the spring unit 30.
The spring unit 30 includes a combination of a coil spring 38, a first cylindrical stroke portion 36, a shock absorber 40, a first spring seat 32, a second cylindrical stroke portion 42, and a second spring seat 48, and a contact member 44. And are configured separately. With such a configuration, the spring unit 30 can be easily disassembled and assembled. Therefore, maintenance of the spring unit 30 can be easily performed.

In the spring unit 30, the contact surface between the shock absorber 40 and the contact member 44 contacts on the axis 38 a of the coil spring 38. With such an arrangement, the spring unit 30 can maintain a stable posture as compared with the case where the contact surfaces of the shock absorber 40 and the contact member 44 are displaced from the shaft center 38a. Further, the lifter 24 can be lifted in a balanced manner by arranging only one shock absorber 40. On the other hand, when the member supporting the shock absorber is in a positional relationship passing through the shaft center 38a and the contact surface between the shock absorber and the contact member is displaced from the shaft center 38a, in order to stabilize the posture of the spring unit A plurality of shock absorbers must be arranged around the axis 38a. In such a configuration, the diameter of the spring unit is increased. Or in order to stabilize the attitude | position of a spring unit, the structure of a coil spring unit must be made into a special structure for exclusive use.
Further, the first tubular member 31 and the second tubular member 46 are arranged rotationally symmetrically with respect to the axis 38a. Thereby, the spring unit 30 can maintain a more stable posture without adjusting the balance.

The spring unit 30 can easily adjust the length and stroke of the coil spring 38. When applied to coil springs 38 and strokes having different lengths, the spring unit 30 only needs to adjust the length of the first cylindrical stroke portion 36 and / or the second cylindrical stroke portion 42.
In the spring unit 30, the shock absorber 40 is disposed in the overlapping range of the first cylindrical stroke portion 36 and the second cylindrical stroke portion 42. With such an arrangement, the length of the spring unit 30 along the extending direction of the coil spring 38 can be shortened.

In the spring unit 30, an oil-type shock absorber 40 is used as a damper for reducing the extension speed of the spring. The shock absorber 40 is displaced at the same speed as the extension speed of the coil spring 38 after contacting the contact member 44. In the oil-type shock absorber 40, the force generated in the direction opposite to the direction of displacement (the direction opposite to the extension direction of the coil spring 38) increases as the displacement speed increases. As shown in FIG. 7, the extension speed of the spring unit 30 gradually decreases after the shock absorber 40 and the contact member 44 contact each other. As the coil spring 38 extends, its elastic force decreases. In the coil spring unit 30, the force of the shock absorber 40 decreases as the coil spring 38 extends. For this reason, it is possible to prevent the extension of the coil spring 38 from being stopped by the force of the shock absorber 40. The shock absorber 40 can achieve the same effect as the oil-type shock absorber 40 by using a known shock absorber such as an air type that utilizes the resistance of the fluid when moving the fluid in the shock absorber 40. .
On the other hand, when an elastic member such as a spring, rubber, sponge or the like is used as the damper, the elastic member abuts against the abutting member 44 and is then subjected to a force opposite to the extending direction of the coil spring 38 due to the deformation of the elastic member. Gradually increases. As a result, the extension of the coil spring 38 may be suddenly stopped by the force of the elastic member. For this reason, when an elastic member is used for the damper, it is necessary to design in consideration of the force of the elastic member.

  In the spring unit 30, the shock absorber 40 abuts against the abutting member 44 in the middle of the extension of the coil spring 38 to reduce the extension speed of the coil spring 38. That is, the extension speed of the coil spring 38 is not reduced before the shock absorber 40 and the contact member 44 come into contact with each other. As a result, it is possible to prevent the lift rate of the lifter 24 from slowing down.

(Modification of the first embodiment)
In the spring unit 30, the shock absorber 40 is supported by the cylindrical first cylindrical stroke portion 36. Further, the contact member 44 is supported by the cylindrical second cylindrical stroke portion 42. However, the member that supports the shock absorber 40 may not be cylindrical. Further, the member that supports the contact member 44 may not be cylindrical. For example, the first cylindrical stroke portion 36 and the second cylindrical stroke portion 42 may have a cylindrical shape with a polygonal cross section. Alternatively, the shape shown in FIG. FIG. 8 shows a spring unit 80 as a modification of the spring unit 30. In FIG. 8, illustration of the coil spring 38 is omitted. As shown in FIG. 8, for example, the member that supports the shock absorber 40 may be a pair of first support columns 84 that are erected from the first spring seat 32 to the inside of the coil spring 38. In this case, it is desirable that the pair of first support columns 84 face each other. Similarly, the members that support the contact member 44 may be a pair of second support columns 82 that are provided on the inner side of the coil spring 38 from the second spring seat 48 and support both ends of the contact member 44. . In this case, it is desirable that the pair of second support columns 82 face each other. The first support column 84 and the second support column 82 may overlap with each other in the radial direction of the coil spring 38 or may be shifted. The first support column 84 and the second support column 82 may be disposed at the same distance from the axis 38a of the coil spring 38, or may be disposed at different distances. The 1st support pillar 84 respond | corresponds to the 1st cylindrical stroke part 36 of 1st Example. The second support column 82 corresponds to the second cylindrical stroke portion 42 of the first embodiment.

  There may be three or more first support columns 84. In this case, the first support column 84 is preferably rotationally symmetric with respect to the axial center 38a of the coil spring 38 (the center of the first spring seat 32). Similarly, the number of the second support pillars 82 may be three or more. In this case, the second support column 82 is preferably rotationally symmetric with respect to the axial center 38a of the coil spring 38 (the center of the second spring seat 48). Further, the first support column 84 and the second support column 82 may not be the same number.

In the spring unit 30, the shock absorber 40 is supported by the first cylindrical stroke portion 36, and the contact member 44 is supported by the second cylindrical stroke portion 42 disposed outside the first cylindrical stroke portion 36. . However, the shock absorber 40 may be supported by the second cylindrical stroke portion 42, and the contact member 44 may be fixed by the first cylindrical stroke portion 36. For example, the above-described configuration can be achieved by fixing the shock absorber 40 to the lower side of the contact member 44 of the first embodiment and closing the lower end of the first cylindrical stroke portion 36.
In the spring unit 30, the first spring seat 32 and the second spring seat 48 have a disk shape. However, the first spring seat 32 and the second spring seat 48 need not be disk-shaped. In this case, each of the first spring seat 32 and the second spring seat 48 is preferably rotationally symmetric with respect to the axis 38 a of the coil spring 38.

(Second embodiment)
FIG. 9 is an exploded perspective view of the spring unit 100 of the second embodiment. In FIG. 9, the coil spring 38 is not shown. In the second embodiment, the same components as those in FIG. 3 are denoted by the same reference numerals as those in FIG. 10 and 11 are longitudinal sectional views of the spring unit 100. FIG. FIG. 10 corresponds to the case where the upper mold 12 is located at the bottom dead center. That is, FIG. 10 shows a state in which the coil spring 38 is most compressed. FIG. 11 shows a state in which the coil spring 38 is most extended.

  The spring unit 100 includes a first member 102 and a second cylindrical member 46. In the second embodiment, the structure of the second cylindrical member 46 is the same as that of the first embodiment. The first member 102 includes a first spring seat 104, a first stroke portion 108, and a first contact portion 110. The first spring seat 104 has a disk shape. The diameter of the first spring seat 104 is substantially the same as the outer diameter of the coil spring 38. A shock absorber 106 is disposed between the first spring seat 104 and the first stroke portion 108. The shock absorber 106 is fixed to the lower surface of the first spring seat 104 and is fixed to the upper end of the first stroke portion 108. The shock absorber 106 is disposed inside the coil spring 38. The first stroke portion 108 branches into two from the lower end of the shock absorber 106 and extends along the axial direction of the coil spring 38. The outer shape of the first stroke portion 108 is smaller than the inner diameter of the second cylindrical stroke portion 42. The first stroke portion 108 is inserted into the second cylindrical stroke portion 42. The first contact portion 110 is fixed to the lower end of the first stroke portion 108. The shock absorber 106 and the first contact portion 110 pass through the axial center 38 a of the coil spring 38. The first member 102 is rotationally symmetrical with respect to the axis 38a.

  As shown in FIG. 10, in a state where the coil spring 38 is most compressed, the first contact portion 110 is positioned away from the contact member 44. In the state of FIG. 10, the lifter 24 is pushed down by the lifter pressing portion 14. The lifter 24 is separated from the stopper 25. If the upper mold | type 12 raises from the state of FIG. 10, the lifter press part 14 will raise with it. When the downward load applied to the lifter 24 by the lifter pressing portion 14 is unloaded, the coil spring 38 extends. As the coil spring 38 extends, the lifter 24 rises. Further, as the coil spring 38 extends, the first member 102 rises. At this time, since the second cylindrical member 46 is in contact with the lower end of the coil spring 38, the position does not change. As the first member 102 rises, the first contact portion 110 moves in a direction approaching the contact member 44.

  The first abutting portion 110 abuts against the abutting member 44 at a position before the coil spring 38 extends to the maximum. When the coil spring 38 extends from this state, the state shown in FIG. 11 is reached. In the state shown in FIG. 11, the lifter 24 is brought into contact with the stopper 25 and the lift of the lifter 24 is stopped. The extension of the coil spring 38 is stopped in the state shown in FIG. As shown in FIG. 11, when the coil spring 38 further expands, the shock absorber 106 is pulled by the first stroke portion 108 and receives energy. The shock absorber 106 consumes energy when the coil spring 38 extends, and extends along the extension direction of the coil spring 38. At this time, the extension speed of the coil spring 38 is reduced.

  In the spring unit 100, the first contact portion 110 contacts the contact member 44 while the coil spring 38 extends from the most compressed state. As a result, the shock absorber 106 is displaced, and the extension speed of the coil spring 38 is reduced. Even when the lifter 24 comes into contact with the stopper 25 and the lift of the lifter 24 is stopped, the spring unit 100 can prevent the workpiece 50 placed on the lifter 24 from slipping off the lifter 24.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the above-described embodiment, the coil spring 38 is used, but another spring such as a disc spring may be used.
In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Vertical view of the mold. The longitudinal cross-sectional view of the spring unit of 1st Example. The disassembled perspective view of the spring unit of 1st Example. The longitudinal cross-sectional view of a spring unit when a coil spring is most compressed. The longitudinal cross-sectional view of the spring unit in the middle of expansion | extension of a coil spring. The longitudinal cross-sectional view of a spring unit when a coil spring extends most. The graph of the extension speed of a coil spring. The disassembled perspective view which shows the modification of the spring unit of 1st Example. The disassembled perspective view of the spring unit of 2nd Example. The longitudinal cross-sectional view of the spring unit of 2nd Example when a coil spring is most compressed. The longitudinal cross-sectional view of the spring unit of 2nd Example when a coil spring is extended most.

Explanation of symbols

10: Mold 30: Spring unit 31: First cylindrical member 32: First spring seat 36: First cylindrical stroke portion 38: Coil spring 40: Shock absorber 42: Second cylindrical stroke portion 44: Contact member 46: Second cylindrical member 48: Second spring seat

Claims (4)

A spring unit that decelerates the extension speed of the spring;
A spring, a first member and a second member;
The first member includes a first spring seat that receives a spring force by abutting against one end portion of the spring, a first stroke portion that extends from the first spring seat to the inside of the spring in the spring extension direction, A first abutting portion fixed to the stroke portion;
The second member is in contact with the other end portion of the spring and receives a spring force, and extends from the second spring seat to the inside of the spring in the direction of extension of the spring and is first than the first contact portion. A second stroke portion that reaches the spring seat side, and a second contact portion that is fixed to the second stroke portion in a range extending on the first spring seat side from the first contact portion,
At least one of the first stroke part and the first contact part has a damper that consumes energy to change the length of the spring in the extension direction;
A spring unit characterized in that the axial center of the spring satisfies a positional relationship passing through the first contact portion, the second contact portion, and the damper.   The spring unit according to claim 1, wherein the first member and the second member are rotationally symmetric with respect to the axis of the spring. The first stroke part is cylindrical,
The second stroke part is cylindrical and the first stroke part is inserted,
The damper is disposed at the first contact portion,
A part of the side wall of the first stroke part is formed with a pair of slits extending in the extension direction of the spring and facing each other,
The spring unit according to claim 2, wherein the second contact portion is inserted into the pair of slits and both ends thereof are supported by the second stroke portion. At least one of the first member and the second member is detachably attached to the spring seat and the stroke portion,
A pair of through-holes facing each other is formed in the second stroke portion,
The spring unit according to claim 3, wherein the second contact portion is inserted and supported through a pair of through holes.

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