JP6421281B1 - jack - Google Patents

Abstract

It is an object of the present invention to provide a jack that can be brought into contact with a support object in a short time without rotating the contact portion by a normal expansion and contraction operation regardless of the distance from the jack to the support object.
As a solution, a base (10) having a slide shaft (12) and a slide shaft support portion (14), and a case (20) assembled to the slide shaft support portion (14) and provided with a case female screw (22) on the inner wall. ) And a screw cylinder male screw (32) formed on the outer wall and screwed into the case female screw (22), and is formed on the inner wall where the outer wall and the central axis coincide with each other. A screw cylinder (30) having an internal thread (36) and an operating portion (34) and a screw cylinder internal thread (36) are screwed together, and the slide shaft (12) is inserted in a non-rotating state along the slide shaft (12). A jack (100) including a movable contact portion (40).

Description

  The present invention relates to a jack, and more particularly to a jack with a screw mechanism that supports a support object such as a workpiece or a table.

  When machining the workpiece, it is necessary to support the workpiece in an appropriate state. When supporting the work, a plurality of extendable jacks are disposed below the work, and the work is adjusted so that the work is horizontal by adjusting the amount of expansion / contraction of the jack.

  As such a jack, the thing of the structure as disclosed by patent document 1 is known, for example. The jack disclosed in Patent Document 1 is provided with a cylindrical main body provided with a female screw part, a male screw part that is screwed into the female screw part, and an operation head that is provided integrally. A first lifting screw rod provided with a female screw portion that opens on the upper surface of the head, a male screw portion that engages with the female screw portion of the first lifting screw rod, and a support head are integrally provided. The second elevating screw 杆 is screwed into the female screw portion provided in the first elevating screw rod more than the pitch of the male screw portion of the first elevating screw rod screwed into the female screw portion of the cylindrical main body. 2 The pitch of the male screw portion of the lifting screw rod is reduced.

Japanese Patent Laid-Open No. 16-169084

  According to the structure of the jack disclosed in Patent Document 1, it is advantageous in that the leveling adjustment of the workpiece of the support object is facilitated. However, if the distance from the jack to the workpiece support surface is longer than the length of the first lifting screw 突出 that can be protruded, the workpiece must be protruded from the first lifting screw 予 め in advance. The problem is that the operation becomes complicated because the support head contacts the support surface while rotating, and the time until the support head contacts the work support surface becomes long. The whereabouts became clear.

  Accordingly, the present invention has been made to solve the above-mentioned problems, and the object of the present invention is as follows. In other words, regardless of the length of the distance from the jack to the support surface of the support object, the jack can be brought into contact with the support surface of the support object in a short time without rotating the contact portion by a normal expansion / contraction operation. It is to provide the configuration.

As a result of intensive studies by the inventors of the present application in order to achieve the above object, the following configuration has been conceived. That is, the present invention includes a slide shaft and a base having a slide shaft support portion that supports the slide shaft in an upright state, a cylindrical shape, and is assembled to the slide shaft support portion and provided with an internal thread on the inner wall. A case and a cylindrical shape, screwed into the case by a male screw provided on the outer wall, and provided with a female screw that is reverse to the male screw of the outer wall on the inner wall whose central axis coincides with the outer wall; and A screw cylinder provided with an operating portion at an upper end portion thereof and screwed into the female screw of the screw cylinder, the slide shaft is inserted into the slide shaft insertion hole in a non-rotating state, and is movable along the slide shaft comprising a contact portion, said sliding shaft, cross-sectional shape have been formed into a shape having an arcuate protrusion in a part of the outer peripheral edge of the body portion, the slide shaft insertion hole, the slide shaft A center hole through which the main body portion is inserted and an outward projecting hole through which the arc-shaped projecting portion is inserted, and both ends of the outer peripheral edge of the arc-shaped projecting portion are lined with an inner peripheral surface of the outer projecting hole; contact with, thereby a jack characterized by movable der Rukoto the contact portion along the slide shaft nonrotatably relative to the slide shaft.

Accordingly, by rotating the screw cylinder with respect to the case assembled to the base on which the slide shaft is erected, the contact portion through which the slide shaft is inserted can be raised without rotating with respect to the case. . In addition, by adopting a configuration in which the operation in which the screw cylinder rises (extends) from the case and the operation in which the abutment part rises (extends) from the screw cylinder is performed at the same time, the abutment part becomes the support surface of the support object. It is possible to shorten the time until contact. Further, the frictional resistance between the slide shaft and the contact portion is reduced, and the slide shaft can be smoothly slid. Furthermore, the contact portion and the slide shaft can always be assembled in an appropriate state.

  Moreover, it is preferable that a retaining stopper is attached to a lower end portion of at least one of the male screw and the contact portion of the screw cylinder.

  Thereby, a screw cylinder or a contact part does not fall from a case.

  Moreover, it is preferable that the contact enlarged diameter part is provided in the upper end part of the said contact part.

  As a result, the contact pressure when the contact portion contacts the support surface of the support object can be reduced, damage to the support object can be prevented, and the support object rich in elasticity. Can be supported in a state where the amount of elastic deformation is reduced.

  Moreover, it is preferable that the said case is provided with the stopper which controls rotation of the said screw cylinder with respect to the said case in arbitrary positions.

  Thereby, unintended rotation of the screw cylinder is prevented, the support state of the support object can be always maintained in an appropriate state, and damage to the support object can be prevented.

  Moreover, it is preferable that a magnet is disposed on the slide shaft support portion.

  Thereby, it becomes possible to adsorb | suck a jack to a magnetic body, and can raise the freedom degree of the installation place of a jack.

  The slide shaft is preferably formed in a polygonal column.

  Thereby, the machining for the slide shaft and the slide shaft insertion hole for fitting the slide shaft and the slide shaft insertion hole of the contact portion can be simplified.

  Moreover, it is preferable to further have a contact attachment that can be attached to and detached from the contact portion.

  Thereby, since a support target object can be supported by the attachment for contact | abutting matched with the shape of the support target object, it can support without damaging a support target object.

  With the configuration of the jack according to the present invention, the contact portion protrudes in a non-rotating state by performing a simple expansion / contraction operation only by rotating the screw cylinder regardless of the distance from the jack to the support surface of the support object. At the same time, it can be brought into contact with the support surface of the support object in a short time.

It is a front view of the jack in a 1st embodiment. It is a top view of the jack in a 1st embodiment. It is a side view of the jack in 1st Embodiment. It is sectional drawing in the IV-IV line in FIG. It is an exploded assembly figure of the jack in a 1st embodiment. It is sectional drawing which shows the state which protruded the screw cylinder and contact part of the jack in 1st Embodiment. It is a disassembled assembly drawing of the jack in 2nd Embodiment. It is explanatory sectional drawing which shows the accommodation state of the slide shaft to the contact part of the jack in 2nd Embodiment. It is sectional drawing which shows the state which protruded the screw cylinder and contact part of the jack in 2nd Embodiment. It is a front view which shows the modification of an attachment. It is a top view of the magnet base attached to the jack in 2nd Embodiment. It is XII-XII sectional drawing of the magnet base attached to the jack in 2nd Embodiment.

(First embodiment)
DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a jack according to the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 6, the jack 100 according to this embodiment includes a base 10 having a slide shaft 12, a case 20 that is cylindrical and assembled to the base 10, and a cylindrical shape that is screwed into the case 20. A screw cylinder 30 and a contact portion 40 that is screwed into the screw cylinder 30 are provided.

  As shown in FIGS. 1, 2, 4 to 6, the base 10 includes a slide shaft 12 formed in a hexagonal column, a slide shaft support portion 14 that supports the slide shaft 12 in an upright state, have. The lower portion of the slide shaft 12 is formed with a small diameter portion over a predetermined range, and an external thread 12A is engraved on the outer peripheral surface of the small diameter portion. The slide shaft support portion 14 has a female screw thread 14A in which the male screw thread 12A of the slide shaft 12 is screwed at the center of the upper surface thereof, and an assembly screw hole 14B for assembling the case 20 is arranged on the outer peripheral surface thereof. It is installed. Further, the slide shaft support portion 14 in the present embodiment is formed of a magnet.

  As shown in FIGS. 4 to 6, the case 20 has a cylindrical shape in which the upper predetermined height range is formed thicker than other portions. A case female screw 22 is engraved on the inner wall (inner peripheral surface) of the thick portion. The center axis of the case female screw 22 of this embodiment is located on the same axis as the center axis of the slide shaft 12. A screw hole 24 is formed in the thick part of the case 20 so as to penetrate the thick part in the radial direction. The screw hole 24 is a stopper that restricts the rotation of the screw cylinder 30 relative to the case 20 at an arbitrary position. 26 can be screwed. The stopper 26 includes a knob portion 26 </ b> A and a contact body 26 </ b> B that can be screwed into the screw hole 24 and can be brought into contact with an outer peripheral surface of a screwed portion of a screw tube male screw 32 of the screw tube 30 described later.

  On the lower side of the case 20, an assembly screw hole 28 is formed so as to be aligned with the assembly screw hole 14 </ b> B disposed on the slide shaft support portion 14. The assembly screw hole 14 </ b> B and the assembly screw hole 28 are disposed at two positions that are opposite to each other by 180 ° when the case 20 is viewed in plan. The case 20 and the base 10 are assembled together by screwing the assembly screw N into the assembly screw hole 28 and the assembly screw hole 14B, respectively.

  As shown in FIGS. 4 to 6, the screw cylinder 30 has a cylindrical shape, and has a screw cylinder male screw 32 provided on the outer wall (outer peripheral surface) and a larger diameter than the screw cylinder male screw 32 at the upper end portion of the screw cylinder male screw 32. And an operation part 34 formed in the above. Further, the screw cylinder 30 has a screw cylinder female screw 36 provided on an inner wall (inner peripheral surface) whose center axis coincides with the outer wall. The screw cylinder 30 is screwed to the case 20 so as to be able to advance and retreat in the axial direction of the screw cylinder 30 and the case 20. The direction of the screw thread of the screw cylinder male screw 32 and the direction of the screw thread of the screw cylinder female screw 36 are opposite to each other (reverse screw). It is preferable to apply a non-slip process to the outer peripheral surface of the operation unit 34. In the present embodiment, the outer peripheral surface of the operation unit 34 is knurled.

  As shown in FIGS. 4 to 6, the contact portion 40 is formed in a cylindrical shape, and the inner space of the contact portion 40 is a slide shaft insertion hole 42. A fitting portion 44 with the slide shaft 12 is formed in a predetermined range in the height direction (extension direction) of the slide shaft insertion hole 42. In this way, by forming the fitting portion 44 only in a partial range in the height direction of the slide shaft insertion hole 42, friction between the slide shaft 12 and the slide shaft insertion hole 42 is reduced. Further, a contact portion male screw 46 that is screwed into the screw tube internal thread 36 of the screw tube 30 is formed on the outer wall (outer peripheral surface) where the slide shaft insertion hole 42 is formed in the contact portion 40.

  The contact portion 40 is screwed into the screw cylinder 30 in a state where the center axis of the contact portion 40 is aligned with the center axis of the screw cylinder 30. The contact portion male screw 46 is formed as a reverse screw to the screw cylinder male screw 32, and the arrangement pitch of the screw threads of the contact section male screw 46 and the arrangement pitch of the screw threads of the screw cylinder male screw 32 are the same pitch. It is. The contact portion 40 formed in this manner is movable in a non-rotating state along the slide shaft 12 by rotating the screw cylinder 30 with respect to the case 20.

  Furthermore, the contact portion 40 in the present embodiment is provided with a contact enlarged diameter portion 48 having a larger diameter than the contact portion male screw 46 at the upper end portion in the height direction of the contact portion male screw 46. . By providing such an enlarged diameter portion for contact 48, the contact pressure at the contact portion with the support object can be reduced as much as possible, and the amount of elastic deformation of the support object is minimized. It is advantageous in that it can be supported in a wet state. Note that a stopper stopper 49 is attached to the lower end portion of the contact portion male screw 46 to prevent the contact portion 40 from coming off from the screw cylinder 30.

  The operation method of the jack 100 in this embodiment is demonstrated. Here, a method of supporting a work (not shown) as a support object with a jack 100 on a magnetic surface plate when grinding is described.

  The jack 100 is used in a state in which it is adsorbed and fixed to a magnetic surface plate by a slide shaft support portion 14 formed of a magnet. When the user rotates the screw cylinder 30 with respect to the case 20 fixed to the base 10, the screw cylinder 30 extends in a direction protruding (separating) from the upper surface of the case 20. The abutting portion 40 is movable along the slide shaft 12 in a non-rotating state with respect to the slide shaft 12. Moreover, the screw cylinder male screw 32 formed on the inner wall of the screw cylinder 30 and the contact portion male screw 46 formed on the outer peripheral surface of the contact portion 40 are formed as reverse screws. Thus, by rotating the screw cylinder 30 with respect to the case 20, the screw cylinder 30 is protruded from the upper surface of the case 20, and at the same time, the contact portion 40 is not rotated along the slide shaft 12 from the screw cylinder 30. It can project (extend). That is, the screw cylinder 30 and the abutting portion 40 can be protruded simultaneously with respect to the case 20 simply by rotating the screw cylinder 30.

  The user only has to rotate the operation portion 34 of the screw cylinder 30 until the abutting enlarged diameter portion 48 of the abutting portion 40 abuts against the workpiece. When the contact enlarged diameter portion 48 comes into contact with the workpiece, the rotation operation of the operation portion 34 is stopped, and the operation of the first jack 100 is finished. Since the work is supported by a plurality of jacks 100, the operations described above may be performed in the same manner for the other jacks 100. When the work is supported by all the jacks 100, the user finely adjusts the contact state of each jack 100 with respect to the work. Thereafter, the user operates the stopper 26 to bring the contact body 26B into contact with the outer peripheral surface (the outer peripheral surface of the screw cylinder male screw 32) of the screw cylinder 30 to the case 20, and the screw cylinder 30 with respect to the case 20 If the rotation is restricted, the work support by the jack 100 is completed. After the workpiece is supported by the jack 100, the workpiece is ground.

  When the jack 100 is removed after the workpiece is ground, the stopper 26 is released and the screw cylinder 30 and the abutting portion 40 are simultaneously placed in the case only by rotating the screw cylinder 30 in the reverse direction. 20 can be entered.

  In this embodiment, as shown in FIG. 6, when the abutting portion 40 of the jack 100 is extended to a predetermined height, the retaining stopper 49 attached to the lower end portion of the abutting portion male screw 46 is provided inside the screw cylinder 30. It contacts the step 38 at the lower end of the thick part of the space. Thereby, the further extension of the contact part 40 is controlled. When the extension of the contact portion 40 with respect to the screw cylinder 30 is restricted, the rotation of the screw cylinder 30 is also restricted, and the extension of the jack 100 as a whole can be restricted. Thus, even if it is the jack 100 which has a screwing part in two places by employ | adopting the structure of the contact part 40 which has the fitting part 44 fitted to the slide shaft 12, only the contact part 40 side is provided. This is advantageous in that it is only necessary to provide a stopper 49 to prevent the stopper from coming off.

(Second Embodiment)
About the jack 100 in this embodiment, about the structure equivalent to the structure of the jack 100 in 1st Embodiment, the detailed description here is abbreviate | omitted by illustrating using the code | symbol used in 1st Embodiment. Yes.

  As shown in FIGS. 7 and 8, the slide shaft 12 in the present embodiment is formed such that the cross-sectional shape has an arcuate protrusion 12 </ b> C at a part of the outer peripheral edge of the main body 12 </ b> B. Such a slide shaft 12 can be formed by cutting the outer peripheral surface of a cylinder with a cutting tool or the like. Here, by using a cutting tool having a rectangular cutting cross section, a part of the outer peripheral edge of the cylinder is cut so as to overlap a part of the cutting cross section in the width direction, thereby having a slide shaft having an arcuate protrusion 12C. 12 was formed. The arcuate projecting portion 12C of the slide shaft 12 is formed such that the width dimension W2 of the arc portion of the arcuate projecting portion 12C is wider than the width dimension W1 on the main body 12B side. Here, the arcuate protrusions 12 </ b> C are arranged at three locations at equal intervals along the outer periphery of the slide shaft 12.

  The slide shaft insertion hole 42 of the contact portion 40 into which the slide shaft 12 is inserted is an outer protrusion hole corresponding to the position of the arcuate protrusion 12C of the slide shaft 12 at a part of the outer peripheral edge of the circular center hole 42A. 42B is arranged. As shown in FIG. 8, when the arcuate protrusion 12 </ b> C of the slide shaft 12 enters the outward protrusion hole 42 </ b> B of the slide shaft insertion hole 42, the contact portion 40 is brought into a non-rotating state with respect to the slide shaft 12. be able to. Further, in the present embodiment, a line contact portion T is formed in which both end portions of the outer peripheral edge of the arc-shaped protruding portion 12C of the slide shaft 12 and the inner peripheral surface of the outer protruding hole 42B of the slide shaft insertion hole 42 are in line contact. Has been. Thereby, the frictional force when the slide shaft 12 slides in the slide shaft insertion hole 42 in a non-rotating state is reduced, and the slide movement of the slide shaft 12 can be made smooth. In addition, by arranging three or more line contact portions T between the slide shaft 12 and the slide shaft insertion hole 42 in the circumferential direction, the slide shaft 12 is assembled to the contact portion 40 (slide shaft insertion hole 42). The slide shaft 12 can be assembled as designed.

  As shown in FIG. 9, in this embodiment, the slide shaft 12 and the slide shaft support portion 14 are integrally formed. The slide shaft support portion 14 is formed in a circular plate, and a bottom female screw 14 </ b> C is formed at the center position of the slide shaft 12 from the bottom surface side of the slide shaft support portion 14. Further, the slide shaft support portion 14 is provided with drain holes 14D penetrating in the thickness direction of the slide shaft support portion 14 at a plurality of locations in the circumferential direction.

  In this manner, the slide shaft support portion 14 in which the slide shaft 12 is integrally formed is disposed in a step portion 29 </ b> A formed inside the bottom portion of the case 20. The slide shaft support portion 14 is provided at a position corresponding to the bottom surface position of the slide shaft support portion 14 of the case 20 while the tips of the three assembly screws N screwed from the side surface of the case 20 are in contact with each other. The C-ring 50 is fitted into the groove 29B so as to be attached to the lower portion of the case 20.

  When the drain hole 14D is not provided in the slide shaft support portion 14, a cap 60 for closing the opening portion of the slide shaft insertion hole 42 of the abutting enlarged diameter portion 48 may be attached (FIG. 7). By disposing a seal member (not shown) at the contact portion of the cap 60 with the slide shaft insertion hole 42, the slide shaft insertion hole 42 can be closed in a sealed state.

  Furthermore, as shown in FIG. 9, a detachable contact attachment 70 can be attached to the slide shaft insertion hole 42 of the contact enlarged diameter portion 48. In accordance with the state of the inner peripheral surface of the slide shaft insertion hole 42 (opening portion of the abutting enlarged diameter portion 48) in the abutting enlarged diameter portion 48, the insertion portion 72 of the abutting attachment 70 is set with a male screw or the like. What is necessary is just to change suitably to dowels etc. Although the contact surface 74 of the contact attachment 70 shown in FIG. 9 is formed in a spherical shape, a V groove 74A and a concave groove 74B formed on the bottom of the V groove 74A as shown in FIG. An abutment attachment 70 formed on the abutment surface 74 can be employed. When the contact portion 40 is formed of a magnetic material, the magnet 76 can be appropriately disposed on the bottom surface of the contact attachment 70. Further, the shape of the contact attachment 70 may correspond to the shape of the contact portion of the support object supported by the jack 100. The contact surface 74 may be provided with a contact surface drain (not shown).

  Further, as shown in FIGS. 11 and 12, the magnet portion 80 can be detachably attached to the slide shaft support portion 14 attached to the case 20. The magnet portion 80 has a cylindrical shape formed in the same shape as the bottom surface shape of the slide shaft support portion 14, and a magnet 82 is embedded in the bottom surface. The magnet portion 80 can be detachably attached to the slide shaft support portion 14 by inserting a screw (not shown) through the screw hole 84 and screwing it into the bottom female screw 14C of the slide shaft support portion 14.

  Further, four drain grooves 86 extending in the radially outward direction of the magnet unit 80 around the screw hole 84 are formed on the upper surface of the magnet unit 80 at equal intervals in the circumferential direction. As a result, the liquid or the like that has entered from the opening portion of the slide shaft insertion hole 42 flows down the gap between the slide shaft insertion hole 42 and the slide shaft 12 and the drain hole 14D, and then is discharged from the jack 100 to the outside of the jack 100. become.

  Although the jack 100 according to the present invention has been described in detail above based on the embodiments, the technical scope of the present invention is not limited to the above embodiments. For example, the base 10 in the above-described embodiment describes a form in which the slide shaft 12 is formed as a hexagonal column, but the shape of the slide shaft 12 is another polygonal column represented by a rectangular column or the like. It can also be formed. Moreover, the shape which provided the convex part or the recessed part in a part of outer peripheral surface of a cylinder is also employable. In short, it is only necessary that the contact portion 40 can be moved along the slide shaft 12 in a non-rotating state with respect to the slide shaft 12 inserted through the slide shaft insertion hole 42.

  Moreover, although the base 10 in 1st Embodiment has demonstrated the form which formed the slide axis | shaft support part 14 with the magnet, the form which attached the magnet to the bottom face of the slide axis | shaft support part 14, or a magnet to the slide axis | shaft support part 14 is demonstrated. It can also be arranged. Furthermore, if a magnet is disposed on the surface plate on which the jack 100 is installed, it is possible to adopt a configuration in which no magnet is disposed by forming the slide shaft support portion 14 from a magnetic material.

  Further, the case 20 is described as having a knob portion 26A and a contact body 26B that is screwed into the screw hole 24 and contacts the outer peripheral surface of the screw cylinder male screw 32 of the screw cylinder 30. The stopper 26 may be configured only by the contact body 26B (not having the knob portion 26A) using an attached set screw (so-called potato screw). Furthermore, the configuration of the stopper 26 can be omitted.

  In addition, the screw cylinder 30 employs a configuration in which the operating portion 34 is formed in a flange shape having a larger diameter than the case 20, but the operating portion 34 can also have a smaller diameter than the case 20. In addition, the operation unit 34 can be configured by a single or a plurality of protrusions protruding from the outer peripheral surface of the upper end portion of the screw cylinder male screw 32. In short, the specific form is not particularly limited as long as the screw cylinder 30 can be rotated.

  Moreover, in the above embodiment, the form which has the diameter-expanding part 48 for contact | abutting formed in the contact | abutting part 40 in the contact | abutting part with a support target object larger diameter than the contact | abutting part external thread 46 is demonstrated. However, it is also possible to adopt a configuration in which the abutting enlarged diameter portion 48 is omitted. Even with the configuration in which the abutting enlarged diameter portion 48 is omitted, the abutting attachment 70 can be used with the insertion portion 72 attached to the slide shaft insertion hole 42.

  Moreover, although the above embodiment demonstrated the form which attached the stopper stopper 49 to the contact part male screw 46 of the contact part 40, it is not limited to this form. For example, a retaining stopper may be attached to both the screw cylinder male screw 32 and the contact part male screw 46, or a stopper stopper may be attached only to the lower end of the screw cylinder male screw 32 of the screw cylinder 30. . When the stopper is attached to the screw cylinder male screw 32 and the contact part male screw 46, it is only necessary to attach it to at least one of the screw cylinder male screw 32 and the contact part male screw 46.

In addition to the above-described modifications, it is possible to adopt a form in which the modifications described in the embodiments are appropriately combined.

Claims (7)

A base having a slide shaft and a slide shaft support portion for supporting the slide shaft in an upright state;
A case having a cylindrical shape and assembled to the slide shaft support portion and provided with an internal thread on the inner wall;
It has a cylindrical shape and is screwed into the case by a male screw provided on the outer wall, and a female screw that is reverse to the male screw of the outer wall is provided on the inner wall where the outer wall and the central axis coincide with each other. A screw cylinder provided with an operation section;
A threaded engagement with the female screw of the screw cylinder, the slide shaft is inserted into the slide shaft insertion hole in a non-rotating state, and a contact portion movable along the slide shaft ,
The slide shaft has a cross-sectional shape formed into a shape having an arcuate protrusion on a part of the outer peripheral edge of the main body,
The slide shaft insertion hole has a center hole through which the main body portion of the slide shaft is inserted, and an outward projection hole through which the arcuate protrusion is inserted,
Both end portions of the outer peripheral edge of the arc-shaped projecting portion are in line contact with the inner peripheral surface of the outer projecting hole, so that the contact portion is non-rotating with respect to the slide shaft along the slide shaft. jack characterized by movable der Rukoto.   The jack according to claim 1, wherein a stopper is attached to a lower end portion of at least one of the male screw and the contact portion of the screw cylinder.   The jack according to claim 1 or 2, wherein an abutting enlarged diameter portion is provided at an upper end portion of the abutting portion.   The jack according to any one of claims 1 to 3, wherein the case is provided with a stopper for restricting rotation of the screw cylinder with respect to the case at an arbitrary position.   The jack according to claim 1, wherein a magnet is disposed on the slide shaft support portion.   The jack according to claim 1, wherein the slide shaft is formed in a polygonal column. Jack according to any one of claims 1-6, characterized in that it comprises the abutting portion abutting attachment detachable further.

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