CN112820498A

CN112820498A - Electric power safety thing allies oneself with insulating cover that shields

Info

Publication number: CN112820498A
Application number: CN202110146572.0A
Authority: CN
Inventors: 蔡益宇; 蔡圣本; 叶寅钢; 蔡显荣; 蔡圣弘; 吕美兰
Original assignee: Individual
Current assignee: Electrification Engineering Co Ltd of China Railway 21st Bureau Group Co Ltd
Priority date: 2021-02-02
Filing date: 2021-02-02
Publication date: 2021-05-18
Anticipated expiration: 2041-02-02
Also published as: CN112820498B

Abstract

The invention discloses an electric power safety thing connection insulation shielding cover which comprises a shielding shell, an anti-skidding device, a tightening device and a fixing assembly, wherein the anti-skidding device is arranged at the center of the shielding shell, the shielding shell is of two groups of symmetrical semicircular shell structures, the tightening device is transversely arranged along the splicing edge of the semicircular shells, arc plates are fixed on the upper semicircular shells on the left side and the right side of the anti-skidding device, arc clamping plates are fixed on the lower semicircular shells on the left side and the right side of the anti-skidding device, so that the arc plates are vertically embedded into the arc clamping plates, and the fixing assembly is further arranged close to the inner side of the tightening device, so that the arc plates in a sandwich structure and the arc clamping plates are fixed.

Description

Electric power safety thing allies oneself with insulating cover that shields

Technical Field

The invention relates to the technical field of insulation shielding, in particular to an electric power safety thing connection insulation shielding cover.

Background

The insulating cover is a protective cover for shielding a live conductor or a non-live conductor. When the safety distance between the worker and the electrified part is not up to the requirement, the insulating cover can be placed on the electrified body in order to prevent the worker from getting electric shock. The insulating cover can be used for insulating protection of distribution transformers, pole-mounted circuit breakers, vacuum circuit breakers, SF, circuit breakers and other equipment of power equipment, various wall bushing, buses, outdoor bus bridges, indoor bus bridges and various post insulators. The insulating boot on the porcelain wheel outside the cable wiring terminal among the distribution transformer now takes turns with the porcelain, and the fixed unstability of porcelain wheel outside and cable produces and rocks, easily drops, leads to the cable to fall to leak in the outside, easily takes place the electric leakage, produces danger to staff's operation safety to and dropping of insulating boot, cause pedestrian's inconvenience.

Accordingly, one skilled in the art provides an electric power safety thing-linked insulation shield to solve the above-mentioned problems of the background art.

Disclosure of Invention

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides an electric power safety thing allies oneself with insulation and shields cover, its is including shielding shell, antiskid, tightening device and fixed subassembly, it is equipped with antiskid to shield the shell center, it is two sets of symmetrical semicircular shell structures to shield the shell, follows the concatenation edge of semicircular shell transversely is equipped with tightening device, is located be fixed with the arc on the semicircular shell in the top on antiskid left and right side, be located be fixed with the arc splint on the semicircular shell in the below on antiskid left and right side, so that in the vertical embedding arc splint of arc, be close to tighten device inboard still is equipped with fixed subassembly, so as to be sandwich structure the arc is fixed with the arc splint.

As a preferred embodiment, the anti-slip device comprises an anti-slip shell, an L-shaped sliding plate and an anti-slip assembly, wherein the left and right end heads at the upper end of the anti-slip shell are slidably connected with a strip-shaped cavity arranged inside the shielding shell, strip-shaped channels are symmetrically arranged at the left and right sides of the middle part of the anti-slip shell, the L-shaped sliding plate is slidably connected inside the strip-shaped channels, the side wall of the outer side end of the L-shaped sliding plate is fixed with the inner side end head of an elastic expansion piece which is transversely arranged, and the outer side end head of the elastic expansion piece is;

the lower end surface of the antiskid shell is connected with antiskid components, and three groups of antiskid components are transversely arranged in a linear manner;

the side wall of the outer side end of the L-shaped sliding plate is also fixed with the upper end of the L-shaped sliding column, and the lower end wall of the outer side end of the L-shaped sliding plate is fixedly connected with positioning plates which are vertically arranged and are transversely arranged in parallel;

the outer side of the lower end of the L-shaped sliding column is sleeved with a clamping assembly, the left side face of the clamping assembly is fixed with the right side face of the arc-shaped ring, an auxiliary sliding column is further fixed on the left side wall of the arc-shaped ring, and the auxiliary sliding column is in sliding connection with a strip-shaped groove formed in the inner wall of the shielding shell.

As the best embodiment, the tightening device comprises Jiong-shaped columns, limiting sliding columns and threaded columns, the left end and the right end of the Jiong-shaped column are embedded into the shielding shell and slide up and down with the inner wall of the shell, the limiting sliding columns are fixed on the outer side wall of the anti-skidding shell and are arranged in two groups in a central symmetry mode, the threaded columns are arranged between the limiting sliding columns, penetrate through the Jiong-shaped columns, and nuts are sleeved on the threaded columns at the outer side ends.

As the best embodiment, the fixing assembly comprises a T-shaped fixing column, a transverse sliding column and a compression spring, the transverse sliding column is fixed on the outer side wall of the anti-skidding shell, the compression spring is sleeved on the outer side face of the transverse sliding column, and the left end and the right end of the compression spring are connected with the T-shaped fixing column.

As a best embodiment, the anti-skid assembly comprises a first elastic telescopic rod, a connecting plate and an anti-skid block, wherein a fixed seat is fixed at the upper end of the first elastic telescopic rod, the fixed seat is hinged and connected with the connecting plate, and the central surface of the upper end of the connecting plate is hinged and connected with the lower end of the anti-skid block.

As the best embodiment, a sliding plate slideway is arranged in the left side plate of the connecting plate, and the connecting plate which is positioned on the outermost side and close to the outer side in the antiskid assembly is clamped between the positioning plates in a sliding connection mode.

As the best embodiment, the non-slip block comprises a T-shaped rod, a micro-rotating shaft and a non-slip mat, the T-shaped rod is fixed at the center of the concave cambered surface of the non-slip block, the left end and the right end of the upper end of the T-shaped rod are hinged to the inner side wall of the non-slip mat, the micro-rod is hinged to the outer side wall of the non-slip mat, the lower end of the micro-rod is hinged to the micro-rotating shaft, the micro-rotating shaft is symmetrically arranged at the left end and the right end of the non-slip block, and a buffer spring is arranged.

As a preferred embodiment, a transverse connecting rod in the T-shaped rod is hinged with the upper end of the vertical fixing rod.

As a preferred embodiment, the clamping assembly comprises a second elastic telescopic rod, an arc-shaped seat and a clamping dislocation piece, the second elastic telescopic rod is fixed at the center of the fixing seat, an auxiliary telescopic rod is arranged outside the second elastic telescopic rod, the upper end of the auxiliary telescopic rod is hinged with the bottom end of the clamping dislocation piece by an outer side surface, and the upper end surface of the second elastic telescopic rod is fixedly connected with the central surface of the bottom end of the clamping dislocation piece;

the left side the fixing base is the circumference and arranges and set up five groups, and is bilateral symmetry setting, and the left side the fixing base is all fixed on the arc, the arc bottom face is connected with tension spring, the tension spring bottom is connected with the shield shell inner wall, is close to one side arc up end and Jiong shape post lower end of tightening means are fixed mutually.

As a preferred embodiment, the corresponding outer wall end of the splicing part of the shielding shell is provided with a clamping handle which is in a scissor shape, and the center of the clamping handle is provided with a fixed shaft so as to conveniently control the opening and closing of the semicircular shell.

Compared with the prior art, the invention provides an electric power safety thing allies oneself with insulating shield cover, has following beneficial effect:

in the invention, through the matching work of the clamping handle, the fixing component and the tightening device, the fixing efficiency of the insulating shielding cover to the porcelain wheel and the cable is improved, the fixing stability with the cable and the porcelain wheel is enhanced, the use and the disassembly are simple and convenient, a plurality of groups of flow channels are arranged on the outer side wall of the anti-slip shell, the accumulation of sundries such as rainwater outside is avoided, through the slidable connecting mode of the anti-slip shell, when the anti-slip component is contacted with the porcelain wheel, the left and right sliding can be carried out automatically, and the sliding between the adjacent anti-slip components is combined, so that the contact between the anti-slip block and the porcelain wheel is more accurate, and when the cable and the porcelain wheel are subjected to the external force, the generated shaking is transmitted to the anti-slip shell, the clamping dislocation piece, the anti-slip block and other structures, the anti-slip mat on the surface of the directly acting porcelain wheel is fixed and stabilized by the T-shaped rod and the, the pulling performance of the clamping dislocation piece is improved, and the force applied by shaking of the shielding shell is reduced, so that the stability, firmness and safety of the structure are improved.

Drawings

FIG. 1 is a schematic view of an insulating shield according to the present invention;

FIG. 2 is a schematic view of the internal structure of the insulating shield according to the present invention;

FIG. 3 is a partial structural view of the insulating shield according to the present invention;

FIG. 4 is an enlarged view of the structure at A of the present invention;

FIG. 5 is an enlarged schematic cross-sectional view of a portion of the insulating shield of the present invention;

in the figure: 1. a shielding housing; 2. an anti-skid device; 3. a tightening device; 4. a fixing assembly; 5. an arc-shaped plate; 6. an arc-shaped splint; 7. a clamping handle; 8. an anti-skid component; 9. a clamping assembly; 10. a tension spring; 21. an anti-slip casing; 22. an L-shaped slide plate; 23. positioning the plate; 24. an L-shaped strut; 25. an elastic extensible member; 26. an arc-shaped ring; 31. jiong-shaped columns; 32. a limiting sliding column; 33. a threaded post; 41. a T-shaped fixing column; 42. a compression spring; 81. an elastic telescopic rod I; 82. a fixed seat; 83. a connecting plate; 84. anti-skid blocks; 85. a T-shaped rod; 86. a micro-rotating shaft; 87. a non-slip mat; 88. a buffer spring; 91. a second elastic telescopic rod; 92. an auxiliary telescopic rod; 93. clamping the dislocation sheet; 94. an arc-shaped seat.

Detailed Description

Referring to fig. 1, the present invention provides a technical solution: an electric power safety thing allies oneself with insulating shielding cover, it includes shielding shell 1, antiskid 2, tightening device 3 and fixed assembly 4, shield the center of shell 1 and have antiskid 2, shield shell 1 to be two sets of symmetrical semicircular shell structures, along the splice edge of the said semicircular shell have tightening device 3 horizontally, locate at said antiskid 2 left, above semicircular shell of right side fix with the arcuate plate 5, locate at said antiskid 2 left, below semicircular shell of right side fix with the arcuate clamp 6, so that said arcuate plate 5 imbeds in the arcuate clamp 6 vertically, close to said tightening device 3 inboard also have fixed assembly 4, in order to fix said arcuate plate 5 and arcuate clamp 6 taking the sandwich structure;

in a preferred embodiment, the arc clamping plates 6 and 5 are provided with cylindrical clamping cavities along the plate surface direction so as to fix the T-shaped fixing posts 41.

Referring to fig. 2, in this embodiment, the anti-skid device 2 includes an anti-skid housing 21, an L-shaped sliding plate 22 and an anti-skid component 8, a left end and a right end of an upper end of the anti-skid housing 21 are slidably connected with a bar-shaped cavity formed inside the shielding housing 1, a left side and a right side of a middle portion of the anti-skid housing 21 are symmetrically provided with bar-shaped empty ways, the bar-shaped empty ways are slidably connected with the L-shaped sliding plate 22, a side wall of an outer side end of the L-shaped sliding plate 22 is fixed with an inner side end of an elastic expansion member 25 transversely arranged, and an outer side end of the elastic;

the lower end surface of the antiskid shell 21 is connected with antiskid components 8, and three groups of antiskid components are transversely arranged in a linear manner;

the side wall of the outer side end of the L-shaped sliding plate 22 is also fixed with the upper end of the L-shaped sliding column 24, and the lower end wall of the outer side end of the L-shaped sliding plate 22 is fixedly connected with positioning plates 23 which are vertically arranged and are transversely arranged in parallel;

the cover has centre gripping subassembly 9 in the 24 lower extreme outsides of L type traveller, centre gripping subassembly 9 left surface is fixed mutually with 26 right flanks of arc ring, just 26 left flanks of arc ring still are fixed with supplementary traveller, supplementary traveller and the bar groove sliding connection who shields 1 inner wall of shell and offer, through the free slip of anti-skidding shell 21 and bar cavity is convenient for anti-skidding subassembly 8 is fixed the porcelain wheel fast, through the lateral sliding of elastic expansion piece 25 and L type slide 22 is flexible, automatically regulated anti-skidding subassembly 8's interval, so that anti-skidding subassembly 8 automatic correction and the laminating precision of porcelain wheel lateral wall, by locating plate piece 23 is spacing to anti-skidding subassembly 2.

Referring to fig. 3, in this embodiment, the tightening device 3 includes Jiong-shaped posts 31, limiting sliding posts 32 and threaded posts 33, the left and right ends of the Jiong-shaped posts 31 are embedded into the shielding shell 1 and slide up and down along the inner wall of the shell thereof, the limiting sliding posts 32 are fixed on the outer side wall of the anti-slip shell 21 and are arranged in two groups in a left and right manner, the threaded posts 33 are arranged between the limiting sliding posts 32 and penetrate through the interior of the Jiong-shaped posts 31, and nuts are sleeved on the threaded posts 33 at the outer ends.

In this embodiment, the fixing assembly 4 includes a T-shaped fixing column 41, a transverse sliding column and a compression spring 42, the transverse sliding column is fixed on the outer side wall of the anti-slip casing 21, the compression spring 42 is sleeved on the outer side surface of the transverse sliding column, and the left end and the right end of the compression spring 42 are connected with the T-shaped fixing column 41.

Referring to fig. 4, in this embodiment, the anti-skid assembly 8 includes a first elastic telescopic rod 81, a connecting plate 83 and an anti-skid block 84, the upper end of the first elastic telescopic rod 81 is fixed with a fixing seat 82, the fixing seat 82 is hinged to the connecting plate 83, and the central surface of the upper end of the connecting plate 83 is hinged to the lower end of the anti-skid block 84, so that the anti-skid block 83 can swing freely and slightly and is fixed to the outer side of the porcelain wheel.

In this embodiment, the inside slide that has seted up of connecting plate 83 left side board, and be located the outside lean on the connecting plate clamp in anti-skidding subassembly 8 in the outside to be connected between locating plate piece 23 sliding, through locating plate piece 23's centre gripping, so that it is right the horizontal wrench movement of connecting plate 83 is injectd, through tensile member on the fixing base 82 is adjusted the vertical wobbling trend of connecting plate 83, so that anti-skidding subassembly 8 can cushion the rocking that the porcelain wheel produced.

In this embodiment, the non-slip block 84 includes T type pole 85, micro-rotating shaft 86 and non-slip pad 87, the center of the concave cambered surface of non-slip block 84 is fixed with T type pole 85, the left and right ends of the upper end of T type pole 85 are connected with the inner side wall of non-slip pad 87 in a hinged manner, the outer side wall of non-slip pad 87 is connected with micro-rod in a hinged manner, the lower end of micro-rod is connected on micro-rotating shaft 86 in a hinged manner, micro-rotating shaft 86 is symmetrically arranged at the left and right ends of non-slip block 84, and a buffer spring 88 is arranged in the inner cavity of non-slip block 84.

In this embodiment, the transverse connecting rod in the T-shaped rod 85 is hinged to the upper end of the vertical fixing rod, and the cushion spring 88 directly acts on the non-slip pad 85, so that the stress in multiple directions generated by the non-slip block 87 is differentiated by combining the connection mode of the internal hinged structure of the T-shaped rod 85, and the non-slip pad 85 is tightly attached to the porcelain wheel.

Referring to fig. 5, in this embodiment, the clamping assembly 9 includes a second elastic telescopic rod 91, an arc-shaped seat 94 and a clamping dislocation piece 93, the second elastic telescopic rod 91 is fixed at the center of the fixing seat 94, an auxiliary telescopic rod 92 is arranged outside the second elastic telescopic rod 91, the upper end of the auxiliary telescopic rod 92 is hinged to the bottom end of the clamping dislocation piece 93 near the outer side surface, and the upper end surface of the second elastic telescopic rod 91 is fixedly connected to the bottom end center surface of the clamping dislocation piece 93;

the left fixing seats 94 are circumferentially arranged in five groups and are arranged in a bilateral symmetry manner, the left fixing seats 94 are fixed on the arc-shaped plate 26, the bottom end face of the arc-shaped plate 26 is connected with a tension spring 10, the bottom end of the tension spring 10 is connected with the inner wall of the shielding shell 1, and the upper end face of the arc-shaped plate 26 close to one side of the tightening device 3 is fixed with the lower end of the Jiong-shaped column 31;

as a preferred embodiment, the clamping and dislocation piece 93 is internally provided with a connecting wheel in an S-shape, so that the connecting wheel can be more stably contacted with the outer side wall of the transverse movement of the cable and the porcelain wheel, the force of the cable and the porcelain wheel on the insulating cover and the force of rebounding to the cable and the porcelain wheel can be differentiated, and the protection performance of the cable and the porcelain wheel can be enhanced.

In this embodiment, a clamping handle 7 is disposed at the end of the outer wall corresponding to the joint of the shielding shell 1, the clamping handle 7 is in the shape of a scissors, a fixing shaft is disposed at the center of the clamping handle for controlling the opening and closing of the semicircular shell, and a torsion spring is sleeved on the outer side of the fixing shaft.

When the concrete implementation, through pressing from both sides tight centre gripping handle 7, open and shield shell 1, the cover is in the porcelain wheel outside, slowly release centre gripping handle 7, laminating through the cooperation of non slipping spur 84 in the anti slipping spur 8 and porcelain wheel, reaction to anti slipping spur 21, slide by oneself, and through connecting plate 83 between the adjacent anti slipping spur 8, adjust its interval of being separated by oneself, treat to shield shell 1 and close the back, open the T type fixed column 41 of the compression in the fixed subassembly 4 earlier, penetrate arc 5, fix in the arc splint 6, rethread revolving nut presses to Jiong shape post 31, and then extrude centre gripping subassembly 9, cooperate tension spring 10 to promote centre gripping subassembly 9 to tighten up simultaneously, make centre gripping dislocation piece 93 closely laminate cable outer wall and the horizontal lateral wall of porcelain wheel.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and the inventive concept within the technical scope of the present invention, and the technical solution and the inventive concept thereof should be covered by the scope of the present invention.

Claims

1. The utility model provides an electric power safety thing allies oneself with insulating cover that shields, its is including shielding shell (1), antiskid (2), tightening means (3) and fixed subassembly (4), its characterized in that: it is equipped with antiskid (2) to shield shell (1) center, shield shell (1) and be two sets of symmetry semicircular shell structure, follow the concatenation edge of semicircular shell transversely is equipped with tightener (3), is located be fixed with arc (5) on the semicircular shell in the top on antiskid (2) left and right side, be located be fixed with arc splint (6) on the semicircular shell in the below on antiskid (2) left and right side, so that in arc (5) vertical embedding arc splint (6), be close to tighten device (3) inboard still is equipped with fixed subassembly (4), so as to be sandwich structure arc (5) are fixed with arc splint (6).

2. The electric power safety thing allies oneself with insulating shield cover of claim 1, characterized in that: the anti-skid device (2) comprises an anti-skid shell (21), an L-shaped sliding plate (22) and an anti-skid component (8), the left end and the right end of the upper end of the anti-skid shell (21) are in sliding connection with a strip-shaped cavity formed in the shielding shell (1), strip-shaped channels are symmetrically formed in the left side and the right side of the middle of the anti-skid shell (21), the L-shaped sliding plate (22) is in sliding connection with the inner side of the strip-shaped channel, the side wall of the outer side end of the L-shaped sliding plate (22) is fixed with the inner side end of an elastic telescopic piece (25) which is transversely arranged, and the outer side end of the elastic telescopic piece (25;

the lower end face of the antiskid shell (21) is connected with antiskid components (8), and three groups of antiskid components are transversely arranged in a linear manner;

the side wall of the outer side end of the L-shaped sliding plate (22) is also fixed with the upper end of the L-shaped sliding column (24), and the lower end wall of the outer side end of the L-shaped sliding plate (22) is fixedly connected with positioning plates (23) which are vertically arranged and are transversely arranged in parallel;

the outer side of the lower end of the L-shaped sliding column (24) is sleeved with a clamping assembly (9), the left side face of the clamping assembly (9) is fixed with the right side face of the arc-shaped ring (26), an auxiliary sliding column is further fixed on the left side wall of the arc-shaped ring (26), and the auxiliary sliding column is connected with a strip-shaped groove formed in the inner wall of the shielding shell (1) in a sliding mode.

3. The electric power safety thing allies oneself with insulating shield cover of claim 1, characterized in that: tight adjusting device (3) are including Jiong shape post (31), spacing traveller (32) and screw thread post (33), Jiong shape post (31) is controlled the end embedding and is shielded inside shell (1), slides from top to bottom rather than shells inner wall, spacing traveller (32) are fixed at anti-skidding shell (21) lateral wall, are that central symmetry left and right sets up two sets ofly, be equipped with screw thread post (33) between spacing traveller (32), and it all with run through Jiong shape post (31) is inside, is located the outside end the cover has the nut on screw thread post (33).

4. The electric power safety thing allies oneself with insulating shield cover of claim 1, characterized in that: the fixing assembly (4) comprises a T-shaped fixing column (41), a transverse sliding column and a compression spring (42), the transverse sliding column is fixed on the outer side wall of the anti-skidding shell (21), the compression spring (42) is sleeved on the outer side face of the transverse sliding column, and the left end and the right end of the compression spring (42) are connected with the T-shaped fixing column (41).

5. The electric power safety thing allies oneself with insulating shield cover of claim 2, characterized in that: the anti-skid component (8) comprises a first elastic telescopic rod (81), a connecting plate (83) and an anti-skid block (84), wherein a fixing seat (82) is fixed at the upper end of the first elastic telescopic rod (81), the connecting plate (83) is hinged to the fixing seat (82), and the central plane of the upper end of the connecting plate (83) is hinged to the lower end of the anti-skid block (84).

6. The electric power safety thing allies oneself with insulating shield cover of claim 5, characterized in that: the inner part of the left side plate of the connecting plate (83) is provided with a sliding plate slideway, and the connecting plate which is positioned at the outermost side and close to the outer side in the anti-skid component (8) is clamped between the positioning plates (23) in a sliding way.

7. The electric power safety thing allies oneself with insulating shield cover of claim 5, characterized in that: non slipping spur (84) include T type pole (85), micro-rotating shaft (86) and slipmat (87), the center of the concave cambered surface of non slipping spur (84) is fixed with T type pole (85), the left and right end of T type pole (85) upper end is connected with slipmat (87) inside wall is articulated, slipmat (87) outside wall is articulated to be connected with micro-pole, the articulated connection of micro-pole lower end is on micro-rotating shaft (86), micro-rotating shaft (86) symmetry sets up at the left and right ends of slipmat (84), is close to the inside cavity of slipmat (84) of micro-rotating shaft (86) inboard is provided with buffer spring (88).

8. The electric power safety thing allies oneself with insulating shield cover of claim 7, characterized in that: and a transverse connecting rod in the T-shaped rod (85) is hinged with the upper end of the vertical fixing rod.

9. The electric power safety thing allies oneself with insulating shield cover of claim 2, characterized in that: the clamping assembly (9) comprises a second elastic telescopic rod (91), an arc-shaped seat (94) and a clamping dislocation piece (93), the second elastic telescopic rod (91) is fixed at the center of the fixed seat (94), an auxiliary telescopic rod (92) is arranged on the outer side of the second elastic telescopic rod (91), the upper end of the auxiliary telescopic rod (92) is hinged to the bottom end of the clamping dislocation piece (93) close to the outer side surface, and the upper end surface of the second elastic telescopic rod (91) is fixedly connected with the center surface of the bottom end of the clamping dislocation piece (93);

the left side fixing base (94) are the circumference and arrange and set up five groups, and are bilateral symmetry and set up, the left side fixing base (94) are all fixed on arc (26), arc (26) bottom face is connected with tension spring (10), tension spring (10) bottom is connected with shielding shell (1) inner wall, is close to end is fixed mutually under one side arc (26) up end and the Jiong shape post (31) of tightening means (3).

10. The electric power safety thing allies oneself with insulating shield cover of claim 1, characterized in that: the outer wall end that corresponds of shielding shell (1) concatenation department is equipped with centre gripping handle (7), centre gripping handle (7) are scissors form, and the center is equipped with the fixed axle to the regulation conveniently opens and shuts of semicircular shell.