CN113018069A

CN113018069A - Obstetric delivery aid for obstetric delivery

Info

Publication number: CN113018069A
Application number: CN202110229659.4A
Authority: CN
Inventors: 邵卫; 石晓; 周国霞
Original assignee: QINGDAO JIAOZHOU CENTRAL HOSPITAL
Current assignee: QINGDAO JIAOZHOU CENTRAL HOSPITAL
Priority date: 2021-03-02
Filing date: 2021-03-02
Publication date: 2021-06-25

Abstract

The invention discloses an obstetric apparatus for obstetrical delivery, which relates to the technical field of medical instruments and comprises a U-shaped seat plate, wherein the front side and the rear side of the right side wall of the U-shaped seat plate are fixedly connected with ear plates, a fixed shaft is fixedly connected between the opposite surfaces of the two ear plates, a hollow tube is sleeved on the fixed shaft, and the right side wall of the U-shaped seat plate is fixedly connected with a U-shaped plate. Through the vertical axis that sets up, the movable sleeve, the swing board, the telescopic link, the apparatus further comprises a rotating shaft, the gear, mutually support between rack and the T shape draw runner, can be when rotating through the pivot, make fixed connection's gear drive both sides meshing's rack simultaneously and carry out the reverse movement in the pivot, the rack of both sides drives swing board and telescopic link respectively again and moves to the inboard, thereby the slide bar that makes swing board and telescopic link all drive the front and back side through lever principle opens to the outside, thereby increase the distance between the two legs of lying-in woman, avoided the lying-in woman to extrude the birth canal when childbirth, lying-in woman's childbirth efficiency has been improved.

Description

Obstetric delivery aid for obstetric delivery

Technical Field

The invention relates to the technical field of medical instruments, in particular to an obstetric apparatus for assisting obstetric delivery in obstetrical department.

Background

Delivery, particularly during the period and process in which the fetus leaves the mother and becomes an independent individual, is divided into three stages, also called three labor stages. The first stage of labor, the ostial dilatation phase. The second phase of labor, fetal delivery. The third labor stage, the placenta delivery stage, refers to the process from the delivery of the fetus to the expulsion of the placenta, and the obstetrical delivery mainly comprises painless delivery, pilot delivery, implicit cesarean section, parturient home delivery and water delivery, wherein the painless delivery is medically called delivery analgesia, is painless natural delivery, and refers to that the pregnant woman is anesthetized with drugs in the natural delivery process, so that the pregnant woman does not feel much pain, and the baby is naturally delivered from the birth canal.

And at the in-process of childbirth, because the difference of pregnant woman physique, often can use the apparatus of help childbirth, little to obstetric forceps greatly arrive the practise midwifery bed, and current practise midwifery bed structure is single mostly, back on the practise midwifery bed is recumbent to the pregnant woman, only simple raise the both legs of pregnant woman and carry out the childbirth, and when the degree of opening at the shank is not enough, can lead to lying-in woman to parturition powerless, and produce the extrusion to the vagina, be unfavorable for baby's output, and current practise midwifery bed can only adopt the posture of lying on the back mostly, and when the pregnant woman lies on the back, the baby can receive the weight influence to drop down, thereby be not convenient for the baby to produce from.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides an obstetric delivery device for assisting delivery of an obstetric department, which solves the problems that after a pregnant woman lies down on a delivery bed, the two legs of the pregnant woman are simply lifted to deliver, when the legs are not opened enough, the delivery of the pregnant woman is powerless, the vagina is squeezed, the delivery of a baby is not facilitated, most of the existing delivery beds can only adopt a supine posture, and when the pregnant woman lies supine, the baby falls downwards under the influence of gravity, so that the baby is not convenient to be produced from the vagina, and the body of the pregnant woman is seriously influenced.

(II) technical scheme

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows: the utility model provides an obstetric apparatus is helped to obstetrical department of obstetric delivery, includes the U-shaped seat, the equal fixedly connected with otic placode in side around the right side wall of U-shaped seat, two fixedly connected with fixed axle between the opposite face of otic placode, the cover is equipped with the hollow tube on the fixed axle, the right side wall fixedly connected with U-shaped plate of U-shaped seat, equal fixedly connected with backup pad, two on the lateral wall around the U-shaped seat the equal fixedly connected with vertical axis of last lateral wall of backup pad, two the outer equal cover of vertical axis is equipped with the movable sleeve, gear room has been seted up on the right side of U-shaped seat, and the front and back end of gear room all is linked together with the external world.

Preferably, the front end and the rear end of the left side of the bottom surface of the U-shaped seat plate and the front end and the rear end of the right side of the bottom surface of the U-shaped plate are fixedly connected with supporting legs.

Preferably, the right-hand member bottom surface fixedly connected with of U-shaped board extends the board, the left side wall of extending the board passes through bearing one and the right-hand member optical axis part fixed connection of threaded rod, the right-hand member of threaded rod extends to extension board right side and hand wheel fixed connection, threaded connection has the thread bush on the threaded rod, the upper end of thread bush is articulated through the lower extreme of articulated seat one with the gangbar.

Preferably, the periphery of the outer side of the fixed shaft is fixedly connected with a backrest plate, the backrest plate is hinged with the upper end of the linkage rod through a second fixedly connected hinged seat, and sponge cushions are arranged on the upper surfaces of the U-shaped seat plate and the backrest plate.

Preferably, two equal fixedly connected with slide bar in outer wall left side of movable sleeve, and two slide bars are the slope setting, two equal sliding connection has a sliding sleeve on the slide bar, two the slide bar all overlaps outward and is equipped with spring one, and the both ends of spring one respectively with the plectane fixed connection of sliding sleeve and slide bar lower extreme setting, two equal fixedly connected with L shape places the board on the opposite face of sliding sleeve, two equal fixedly connected with baffle on the opposite face of board is placed to L shape.

Preferably, the front side the outer wall of the right side of the movable sleeve is fixedly connected with a swing plate, the swing plate is provided with a chute, and the rear side the outer wall of the right side of the movable sleeve is fixedly connected with a telescopic rod.

Preferably, bearing two and pivot fixed connection are all passed through at the upper and lower lateral wall middle part of gear room, and the left side wall front and back end of gear room is the inclined plane setting, fixedly connected with gear in the pivot, the left and right sides of gear all meshes the rack, two equal fixedly connected with T shape draw runner, two on the looks back of rack T shape draw runner sliding connection is in the T shape spout of seting up on the lateral wall about the gear room respectively, and the left side the front end fixedly connected with movable rod of rack, and movable rod sliding connection is in the spout, the right side the rear end of rack is articulated with the telescopic link right-hand member.

Preferably, the lower end of the rotating shaft extends to a rocker fixedly connected below the U-shaped seat plate, a sliding hole is formed in the right side of the rocker, a bolt is slidably connected into the sliding hole, a handle is fixedly connected to the lower end of the bolt, a spring II is sleeved outside the bolt, two ends of the spring II are fixedly connected with the handle and the rocker respectively, a plurality of positioning holes are formed in the bottom surface of the U-shaped seat plate, the positioning holes are annularly arranged by taking the rotating shaft as the center of a circle, and the bolt is clamped with one of the positioning holes.

(III) advantageous effects

The invention has the beneficial effects that:

1. this obstetric apparatus is helped to obstetrical department of obstetric delivery, vertical axis through setting up, the movable sleeve, the swing board, the telescopic link, the apparatus further comprises a rotating shaft, can rotate through the pivot between rack and the T shape draw runner, make in the pivot fixed connection's gear drive both sides meshing's rack simultaneously and carry out the reverse movement, the rack of both sides drives swing board and telescopic link respectively again and removes to the inboard, thereby the slide bar that makes swing board and telescopic link all drive the front and back side through lever principle opens to the outside, thereby increase the distance between the two legs of lying-in woman, avoided the lying-in woman to extrude the birth canal when childbirth, lying-in woman's childbirth efficiency has been improved.

2. This obstetric apparatus is helped to obstetrical department of obstetric delivery, through the extension board that sets up, the threaded rod, the hand wheel, the thread bush, mutually support between gangbar and the back board, can be through rotating the hand wheel, make the hand wheel drive fixed connection's threaded rod rotate, the threaded rod drives threaded connection's thread bush when rotating and removes, the thread bush drives articulated gangbar lower extreme again and removes, the lower extreme of gangbar drives upper end articulated back board in the in-process that removes and rises, make the back board use the fixed axle to rotate as the axle center, stop behind the suitable position of inclining to, position when having realized parturient delivery is adjusted, thereby make the baby change the output when childbirth through the action of gravity.

3. This obstetrical department's obstetric apparatus of helping childbirth of obstetrical department, slide bar through setting up, the sliding sleeve, spring one, mutually supporting between board and the baffle is placed to the L shape, can make the lying-in woman sit on the U-shaped seat, lift the both legs of lying-in woman to the L shape and place on the board, place the height of board and adjust to the L shape according to the different length of lying-in woman thigh, the knee flexion of lying-in woman drives the L shape and places board downstream, the L shape is placed the board and is driven fixed connection's sliding sleeve and slide down on the slide bar, thereby make sliding sleeve extrusion spring one, stop the action after removing to comfortable position, thereby realize helping parturient to different thigh lengths, the practicality is improved.

Drawings

FIG. 1 is a schematic front sectional view of the present invention;

FIG. 2 is a schematic top sectional view of a U-shaped seat plate according to the present invention;

FIG. 3 is a schematic view of a partial bottom view of the U-shaped seat of the present invention.

In the figure: 1U-shaped seat plate, 2 ear plates, 3 fixed shafts, 4 hollow pipes, 5U-shaped plates, 6 supporting plates, 7 vertical shafts, 8 movable sleeves, 9 gear chambers, 10 supporting legs, 11 extending plates, 12 threaded rods, 13 hand wheels, 14 threaded sleeves, 15 linkage rods, 16 backrest plates, 17 sponge cushion, 18 sliding rods, 19 sliding sleeves, 20 first springs, 21L-shaped placing plates, 22 baffle plates, 23 swinging plates, 24 sliding grooves, 25 telescopic rods, 26 rotating shafts, 27 gears, 28 racks, 29T-shaped sliding strips, 30T-shaped sliding grooves, 31 movable rods, 32 rocking rods, 33 sliding holes, 34 bolts, 35 grips, 36 second springs and 37 positioning holes.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1-3, the present invention provides a technical solution: an obstetric apparatus for obstetrical department of obstetrical department, comprising a U-shaped seat plate 1, wherein the front side and the rear side of the right side wall of the U-shaped seat plate 1 are fixedly connected with ear plates 2, a fixed shaft 3 is fixedly connected between the opposite surfaces of the two ear plates 2, a hollow tube 4 is sleeved on the fixed shaft 3, the back plate 16 can rotate by arranging the fixed shaft 3 and the hollow tube 4, thereby the back of a pregnant woman can incline, the pregnant woman can give a seated position to deliver, the delivery effect is improved, the right side wall of the U-shaped seat plate 1 is fixedly connected with a U-shaped plate 5, by arranging the U-shaped plate 5, the back plate 16 can be horizontally placed, enough space is provided for accommodating the back plate 16, the space utilization rate is improved, the front side wall and the rear side wall of the U-shaped seat plate 1 are fixedly connected with supporting plates 6, the upper side walls of the two supporting plates 6 are respectively and fixedly connected with a vertical shaft 7, two vertical shafts 7 are respectively, the sliding rods 18 on the two sides can rotate by taking the vertical shaft 7 as an axis, so that the opening angle between the two legs of a puerpera can be adjusted, the gear chamber 9 is arranged on the right side of the U-shaped seat plate 1, and the front end and the rear end of the gear chamber 9 are communicated with the outside.

The equal fixedly connected with supporting leg 10 of bottom surface right side front and back end and the U-shaped plate 5's bottom surface right side front and back end around the bottom surface left side of U-shaped seat 1 through setting up supporting leg 10, can make this practise midwifery ware more stable when placing.

An extension plate 11 is fixedly connected to the bottom surface of the right end of the U-shaped plate 5, the left side wall of the extension plate 11 is fixedly connected with the right end optical axis part of a threaded rod 12 through a bearing I, the right end of the threaded rod 12 extends to the right side of the extension plate 11 and is fixedly connected with a hand wheel 13, a threaded sleeve 14 is in threaded connection with the threaded rod 12, the upper end of the threaded sleeve 14 is hinged with the lower end of a linkage rod 15 through a hinge seat I, the threaded rod 12 is driven to rotate by the hand wheel 13 through the mutual matching of the extension plate 11, the threaded rod 12, the hand wheel 13, the threaded sleeve 14, the linkage rod 15 and a back plate 16, the hand wheel 13 is rotated, the threaded rod 12 drives the threaded sleeve 14 in threaded connection to move when rotating, the threaded sleeve 14 drives the lower end of the hinged linkage rod 15 to move, the lower end of the back plate 16, which is hinged, the backrest plate 16 rotates by taking the fixed shaft 3 as an axis and stops after inclining to a proper position, so that the position of the parturient during delivery is adjusted, and the baby is easier to deliver during delivery under the action of gravity.

The outer circumferential surface of the fixed shaft 3 is fixedly connected with a backrest plate 16, the backrest plate 16 is hinged with the upper end of the linkage rod 15 through a fixedly connected hinge seat II, sponge cushion 17 are arranged on the upper surfaces of the U-shaped seat plate 1 and the backrest plate 16, and the sponge cushion 17 is arranged on the upper surfaces of the U-shaped seat plate 1 and the backrest plate 16, so that a puerpera can feel more comfortable during childbirth on the obstetric apparatus.

The left sides of the outer walls of the two movable sleeves 8 are fixedly connected with sliding rods 18, the two sliding rods 18 are obliquely arranged, the sliding sleeves 19 are connected to the two sliding rods 18 in a sliding mode, the legs of a puerpera can be lifted to the L-shaped placing plates 21 when the puerpera sits on the U-shaped seat plate 1 through the mutual matching of the arranged sliding rods 18, the sliding sleeves 19, the first springs 20, the L-shaped placing plates 21 and the baffle plates 22, the height of the L-shaped placing plates 21 is adjusted according to the different lengths of thighs of the puerpera, the bent parts of knees of the puerpera drive the L-shaped placing plates 21 to move downwards, the L-shaped placing plates 21 drive the fixedly connected sliding sleeves 19 to slide downwards on the sliding rods 18, the first springs 20 are extruded by the sliding sleeves 19 and stop moving to comfortable positions, accordingly, the puerpera with different thigh lengths can be assisted in labor, the practicability is improved, the first springs 20 are sleeved outside the two sliding rods 18, and the both ends of spring one 20 respectively with sliding sleeve 19 and the plectane fixed connection that the slide bar 18 lower extreme set up, equal fixedly connected with L shape on the opposite face of two sliding sleeves 19 places board 21, equal fixedly connected with baffle 22 on the opposite face of board 21 is placed to two L shapes, through setting up baffle 22, can make lying-in woman's knee flexion place when placing on board 21 is placed to the L shape, can not the landing.

The right side outer wall fixedly connected with swing board 23 of front side movable sleeve 8 has seted up spout 24 on the swing board 23, and the right side outer wall fixedly connected with telescopic link 25 of rear side movable sleeve 8 through setting up swing board 23 and telescopic link 25, can make the better drive both sides slide bar 18 of both sides rack 28 carry out the angle modulation, has realized the integrality of structure.

The middle parts of the upper side wall and the lower side wall of the gear chamber 9 are fixedly connected with a rotating shaft 26 through a bearing II, the front end and the rear end of the left side wall of the gear chamber 9 are arranged in an inclined plane, a gear 27 is fixedly connected on the rotating shaft 26, racks 28 are meshed on the left side and the right side of the gear 27, T-shaped sliding strips 29 are fixedly connected on the opposite sides of the two racks 28, the two T-shaped sliding strips 29 are respectively and slidably connected in T-shaped sliding grooves 30 formed in the left side wall and the right side wall of the gear chamber 9, the racks 28 on the two sides can be more stable when moving through the arrangement of the T-shaped sliding strips 29 and the T-shaped sliding grooves 30, a movable rod 31 is fixedly connected at the front end of the rack 28 on the left side, the movable rod 31 is slidably connected in the sliding grooves 24, the rear end of the rack 28 on the right side is hinged with the right end of a telescopic rod 25, and the movable rod 31 is matched, can be when rotating through pivot 26, make pivot 26 go up fixed connection's gear 27 and drive both sides meshed rack 28 simultaneously and carry out the antiport, the rack 28 of both sides drives swing board 23 and telescopic link 25 respectively again and moves to the inboard, thereby make swing board 23 and telescopic link 25 all drive the slide bar 18 of front and back side through lever principle and open to the outside, thereby increase the distance between the two legs of lying-in woman, avoided the lying-in woman to extrude the birth canal when the childbirth, the childbirth efficiency of lying-in woman has been improved.

The lower end of the rotating shaft 26 extends to the lower part of the U-shaped seat plate 1 and is fixedly connected with a rocker 32, the right side of the rocker 32 is provided with a sliding hole 33, the sliding hole 33 is internally and slidably connected with a bolt 34, the lower end of the bolt 34 is fixedly connected with a handle 35, a spring 36 is sleeved outside the bolt 34, two ends of the spring 36 are respectively and fixedly connected with the handle 35 and the rocker 32, the bottom surface of the U-shaped seat plate 1 is provided with a plurality of positioning holes 37, the positioning holes 37 are annularly arranged by taking the rotating shaft 26 as a circle center, the bolt 34 is clamped with one of the positioning holes 37, through the mutual matching of the rotating shaft 26, the rocker 32, the sliding hole 33, the bolt 34, the handle 35, the spring 36 and the positioning holes 37, the bolt 34 can not be clamped with the positioning holes 37 by pulling the handle 35 downwards, and then the rocker 32 is rotated, so that the rocker 32 drives the rotating shaft 26 which is fixedly, after the adjustment is finished, the handle 35 is released, and the bolt 34 is inserted into the positioning hole 37 again under the pulling force of the second spring 36 for fixing, so that the structural integrity is realized.

The method comprises the following operation steps:

s1, when the obstetric apparatus is used, firstly, a puerpera sits on the U-shaped seat plate 1, then, the two legs of the puerpera are lifted to the L-shaped placing plate 21, the height of the L-shaped placing plate 21 is adjusted according to different lengths of thighs of the puerpera, the knee bending part of the puerpera drives the L-shaped placing plate 21 to move downwards, the L-shaped placing plate 21 drives the fixedly connected sliding sleeve 19 to slide downwards on the sliding rod 18, and therefore the sliding sleeve 19 extrudes the first spring 20 and stops moving after moving to a comfortable position;

s2, adjusting the inclination angle of the back of the lying-in woman, firstly rotating the hand wheel 13 to enable the hand wheel 13 to drive the fixedly connected threaded rod 12 to rotate, driving the threaded sleeve 14 in threaded connection to move when the threaded rod 12 rotates, driving the lower end of the hinged linkage rod 15 to move by the threaded sleeve 14, driving the backrest plate 16 hinged to the upper end to lift in the moving process of the lower end of the linkage rod 15, enabling the backrest plate 16 to rotate by taking the fixed shaft 3 as an axis, and stopping after inclining to a proper position;

s3, when the parturient is parturient, the opening angle between the legs of the parturient is adjusted, the handle 35 is pulled out downward to prevent the latch 34 from engaging with the positioning hole 37, the rocker 32 is rotated to drive the fixed shaft 26 to rotate, the gear 27 fixed on the shaft 26 drives the racks 28 engaged at both sides to move in opposite directions, the rack 28 at the left side drives the movable rod 31 at the front end to move inward, the movable rod 31 drives the swinging plate 23 to rotate around the vertical shaft 7, so that the movable rod 31 slides in the sliding slot 24, and at the same time, the rack 28 at the right side drives the telescopic rod 25 connected at the rear end to rotate around the vertical shaft 7, so that the swinging plate 23 and the telescopic rod 25 both drive the sliding rods 18 at the front and rear sides to open outwards through the lever principle, thereby increasing the distance between the legs of the parturient.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An obstetric apparatus for obstetrical delivery, comprising a U-shaped seat plate (1), characterized in that: equal fixedly connected with otic placode (2) of side around the right side wall of U-shaped seat (1), two fixedly connected with fixed axle (3) between the opposite face of otic placode (2), the cover is equipped with hollow tube (4) on fixed axle (3), the right side wall fixedly connected with U-shaped board (5) of U-shaped seat (1), equal fixedly connected with backup pad (6), two on the lateral wall around U-shaped seat (1) the equal fixedly connected with vertical axis (7) of last lateral wall of backup pad (6), two vertical axis (7) all overlap and are equipped with movable sleeve (8), gear room (9) have been seted up on the right side of U-shaped seat (1), and the front and back end of gear room (9) all is linked together with the external world.

2. An obstetric device for obstetrical delivery as claimed in claim 1, wherein: the front end and the rear end of the left side of the bottom surface of the U-shaped seat plate (1) and the front end and the rear end of the right side of the bottom surface of the U-shaped plate (5) are fixedly connected with supporting legs (10).

3. An obstetric device for obstetrical delivery as claimed in claim 1, wherein: the right-hand member bottom surface fixedly connected with of U-shaped board (5) extends board (11), the left side wall of extending board (11) passes through the right-hand member optical axis part fixed connection of bearing one with threaded rod (12), the right-hand member of threaded rod (12) extends to and extends board (11) right side and hand wheel (13) fixed connection, threaded connection has thread bush (14) on threaded rod (12), the upper end of thread bush (14) is articulated through the lower extreme of articulated seat one with gangbar (15).

4. An obstetric device for obstetrical delivery as claimed in claim 1, wherein: fixedly connected with back board (16) on the outside periphery of fixed axle (3), and back board (16) are articulated through the articulated seat two of fixed connection and the upper end of gangbar (15), the upper surface of U-shaped seat (1) and back board (16) all is provided with sponge cushion (17).

5. An obstetric device for obstetrical delivery as claimed in claim 1, wherein: two equal fixedly connected with slide bar (18) in outer wall left side of movable sleeve (8), and two slide bar (18) are the slope setting, two equal sliding connection has sliding sleeve (19), two on slide bar (18) all overlap and be equipped with spring one (20) outward, and the both ends of spring one (20) respectively with the plectane fixed connection of sliding sleeve (19) and slide bar (18) lower extreme setting, two equal fixedly connected with L shape places board (21), two on the opposite face of sliding sleeve (19) the L shape is placed equal fixedly connected with baffle (22) on the opposite face of board (21).

6. An obstetric device for obstetrical delivery as claimed in claim 1, wherein: the front side the right side outer wall fixedly connected with swing board (23) of movable sleeve (8), swing board (23) are last to have seted up spout (24), the rear side the right side outer wall fixedly connected with telescopic link (25) of movable sleeve (8).

7. An obstetric device for obstetrical delivery according to claim 1 or 6, wherein: the upper and lower lateral wall middle part of gear room (9) all is through bearing two and pivot (26) fixed connection, and the left side wall front and back end of gear room (9) is the inclined plane setting, fixedly connected with gear (27) are gone up in pivot (26), the side all meshes rack (28), two about gear (27) equal fixedly connected with T shape draw runner (29), two on the looks back of rack (28) T shape draw runner (29) sliding connection is in T shape spout (30) of seting up on the lateral wall about gear room (9) respectively, the left side the front end fixedly connected with movable rod (31) of rack (28), and movable rod (31) sliding connection is in spout (24), the right side the rear end and telescopic link (25) right-hand member of rack (28) are articulated.

8. An obstetric device for obstetrical delivery as claimed in claim 1, wherein: the lower extreme of pivot (26) extends to U-shaped seat (1) below fixedly connected with rocker (32), sliding hole (33) have been seted up on the right side of rocker (32), sliding connection has bolt (34) in sliding hole (33) the lower extreme fixedly connected with handle (35) of bolt (34), bolt (34) overcoat is equipped with spring two (36), and the both ends of spring two (36) respectively with handle (35) and rocker (32) fixed connection, a plurality of locating holes (37) have been seted up to the bottom surface of U-shaped seat (1), and a plurality of locating holes (37) use pivot (26) to be cyclic annular arrangement as the centre of a circle, and one joint in bolt (34) and a plurality of locating hole (37).