CN217675196U

CN217675196U - Automatic logistics conveying platform for forklift gantry structural part

Info

Publication number: CN217675196U
Application number: CN202221580210.9U
Authority: CN
Inventors: 李金海; 汪存宝; 刘海军; 葛中
Original assignee: Hefei Taijin Automation Technology Co ltd
Current assignee: Hefei Taijin Automation Technology Co ltd
Priority date: 2022-06-22
Filing date: 2022-06-22
Publication date: 2022-10-28
Anticipated expiration: 2032-06-22

Abstract

The utility model relates to the technical field of automatic logistics conveying of forklift door structural parts, and discloses an automatic logistics conveying platform for forklift door structural parts, which comprises a conveying platform, a supporting and clamping mechanism and a conveying mechanism, wherein the conveying platform is used for supporting and clamping the forklift door structural parts; the positioner drives the conveying platform to turn 180 degrees; the moving trolley is arranged on the outer side of the conveying platform and can move to the position right below the conveying platform along the direction which is vertical to the axial direction of the turnover shaft of the positioner; and connect the material platform for steadily receive the fork truck portal structure on the conveying platform after the upset, the utility model discloses utilize the conveying platform cooperation travelling car that can overturn and connect the material platform, can with the quick follow conveying platform of fork truck portal structure transfer to the travelling car on, then remove to suitable position by the travelling car again, improve work efficiency to can reach the purpose that changes the direction of delivery of fork truck portal structure fast in limited space, reduce the area of whole device.

Description

Automatic logistics conveying platform for forklift gantry structural part

Technical Field

The utility model relates to an automatic commodity circulation of fork truck portal structure carries technical field, specifically is an automatic commodity circulation conveying platform of fork truck portal structure.

Background

The forklift mast is a main bearing structure of a forklift load taking device, is also a mechanism for lifting goods by the forklift, and is also called a mast. In the engineering forklift industry, the types and models of products are relatively close, the structures and the external dimensions of some parts are relatively close, and when structural parts are welded, the parts with the same structures are generally classified and welded.

At present, adopt equipment such as hoist to hoist and carry suitable position with fork truck portal structure spare from conveying equipment at fork truck portal structure spare usually, specific step is: firstly, clamping a clamp used for clamping a forklift portal structural member on a lifting appliance onto the forklift portal structural member, then starting the lifting appliance to drive the forklift portal structural member to rise to a certain height, and then moving and placing the forklift portal structural member to a proper position by using the lifting appliance; the whole operation process is very complicated, a large amount of time can be consumed before the forklift gantry structural member is hoisted, the actual working efficiency is reduced, the use of the lifting appliance can occupy a large amount of space, and the use requirements under some special conditions can not be met.

SUMMERY OF THE UTILITY MODEL

The problem that work efficiency is low and occupation space is big when solving present fork truck portal structure and carry, the utility model provides a following technical scheme: an automatic commodity circulation conveying platform of fork truck portal structure includes:

the conveying platform is used for supporting and clamping a forklift portal structural member;

the positioner drives the conveying platform to turn 180 degrees;

the moving trolley is arranged on the outer side of the conveying platform and can move to the position right below the conveying platform along the direction which is vertical to the axial direction of the turnover shaft of the positioner; and

the material receiving platform is arranged on the movable trolley, can perform lifting motion and is used for stably receiving forklift portal structural members on the conveying platform after overturning.

Preferably, the material receiving platform comprises two jacking material receiving mechanisms, and the two jacking material receiving mechanisms can perform spacing adjustment along the direction axially parallel to the turning shaft of the positioner.

The distance between the two jacking receiving mechanisms can be adjusted, so that the two jacking receiving mechanisms can receive forklift portal structural members with different sizes and specifications, and the application range is wide.

Preferably, the jacking material receiving mechanism comprises a jacking cylinder and a material receiving plate arranged at the free end of the jacking cylinder, and the length direction of the material receiving plate is consistent with the moving direction of the moving trolley.

The jacking cylinder can drive the material receiving plate to perform lifting motion, so that after the conveying platform drives the forklift gantry structural member on the conveying platform to overturn, the jacking cylinder is used for driving the material receiving plate to ascend to the height contacting with the forklift gantry structural member, and stable and safe receiving of the forklift gantry structural member is achieved.

Preferably, backing plates are mounted at two end portions of the top surface of the material receiving plate along the length direction of the material receiving plate, and limiting blocks are mounted at two end portions of the top surface of each backing plate along the length direction of the material receiving plate.

The backing plate collocation stopper can carry on spacingly to fork truck portal structure, prevents that fork truck portal structure from receiving flitch landing because of inertia etc..

The movable trolley comprises a base, two mutually parallel slide rails fixedly arranged relative to the positioner base and a driving assembly for driving the base to slide on the two slide rails, and the jacking material receiving mechanism is slidably mounted on the base and locked at the position on the base through a locking assembly.

The base is used for supporting the jacking receiving mechanism, and the jacking receiving mechanism and the base are convenient to slide and install.

The driving assembly comprises a double-output-shaft speed reducing motor which is arranged on one end of the base along the sliding direction of the base and two output shafts of which respectively face the two sliding rails, and two driving rollers which are fixedly connected with the two output shafts of the double-output-shaft speed reducing motor through two transmission shafts, wherein the two driving rollers are respectively connected onto the two sliding rails in a rolling manner.

The double-output-shaft speed reduction motor can drive the two driving idler wheels to synchronously rotate at the same time, so that the base can stably move on the sliding rail.

The conveying platform comprises a roller conveyor and a clamping device for clamping the forklift portal structural member on the roller conveyor.

The roller conveyor is used for conveying workpieces, namely forklift mast structural parts, and the clamping device is used for clamping the forklift mast structural parts.

The locking assembly comprises a fixing plate, a bottom plate, a screw thread and a handle, wherein the fixing plate is installed inside the base and horizontally arranged, the bottom plate is installed at the bottom end of the jacking material receiving mechanism, the screw thread penetrates through the bottom plate and the stud is arranged along the vertical direction, the handle is fixed to the top end of the stud, and the bottom end of the stud can be pressed on the fixing plate by rotating the handle.

The locking assembly can lock and fix the jacking material receiving mechanism at a proper position on the base, so that the jacking material receiving mechanism is prevented from sliding in the process of supporting the forklift portal structural member, and the stability and the safety of the forklift portal structural member in the conveying process are improved.

The clamping device comprises a shell, two pushing cylinders and two tensioning claws, wherein the shell is arranged on a roller conveyor, the length direction of the shell is vertical to the conveying direction of the roller conveyor, the two pushing cylinders are arranged inside the shell and can stretch and stretch along the length direction of the shell, the two pushing cylinders are symmetrically distributed, the two tensioning claws are respectively arranged at the free ends of the two pushing cylinders, and the top ends of the tensioning claws penetrate through the inner top wall of the shell and extend to the upper side of the shell.

Two cylinders cooperate two tight claws that rise, just can press from both sides tight fixedly to fork truck portal structure, simple structure, and use cost is low.

Compared with the prior art, the beneficial effects of the utility model are that:

1. this automatic commodity circulation conveying platform of fork truck portal structure utilizes the conveying platform cooperation travelling car that can overturn and connects the material platform, can transfer the fork truck portal structure is quick on the travelling car from conveying platform, then remove to suitable position by the travelling car again, improve work efficiency to can reach the purpose that changes the direction of delivery of fork truck portal structure fast in limited space, reduce the area of whole device.

2. This automatic commodity circulation conveying platform of fork truck portal structure utilizes and connects the material platform to rise and the principle that reduces for fork truck portal structure can be fast and stable be received material platform and receive, avoids the fork truck portal structure to strike the condition emergence of the fork truck portal structure damage that appears on connecing the material platform.

3. This automatic commodity circulation conveying platform of fork truck portal structure spare, backing plate collocation stopper can carry on spacingly to the fork truck portal structure spare, prevents that the fork truck portal structure spare from connecing flitch landing because of inertia etc..

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic structural view of the movable trolley of the present invention;

fig. 3 is a schematic structural view of the material receiving platform of the present invention;

fig. 4 is a schematic sectional structural view of the clamping device of the present invention;

fig. 5 is a schematic cross-sectional structural view of the locking assembly of the present invention.

In the figure: 100. a conveying platform; 110. a roller conveyor; 120. a clamping device; 121. a push cylinder; 122. a tensioning claw; 123. a housing; 200. a position changing machine; 210. a support; 300. moving the trolley; 310. a base; 320. a slide rail; 330. a drive assembly; 331. a double output shaft speed reducing motor; 332. a drive shaft; 333. a driving roller; 334. a driven roller; 335. a drag chain; 336. a groove plate; 340. a locking assembly; 341. a fixing plate; 342. a base plate; 343. a stud; 344. a handle; 350. a linear guide rail; 400. a material receiving platform; 410. jacking the receiving mechanism; 411. jacking a cylinder; 412. a material receiving plate; 4121. a base plate; 4122. a limiting block; 420. a guide bar; 500. fork truck portal structure.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element to which the reference is made must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, and for example, "connected" may be either fixedly connected or detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1 to 5, the automatic logistics conveying platform of the forklift mast structure in the embodiment mainly comprises four parts, namely a conveying platform 100, a positioner 200, a moving trolley 300 and a material receiving platform 400; the conveying platform 100 is used for supporting and clamping the forklift mast structural member 500, and the forklift mast structural member 500 is prevented from moving; the positioner 200 is used for driving the conveying platform to turn over for 180 degrees, namely, turning over the forklift gantry structural member 500 originally positioned at the top end of the conveying platform 100 to the bottom end of the conveying platform 100 so as to provide a foundation for the next operation; the movable trolley 300 is arranged on the outer side of the conveying platform 100, the movable trolley 300 can move to the position right below the conveying platform 100 along the direction vertical to the axial direction of the overturning shaft of the positioner 200, and the forklift gantry structural member 500 on the conveying platform 100 can be received only after the movable trolley 300 moves to the position right below the conveying platform 100; the material receiving platform 400 is arranged on the moving trolley 300 and can perform lifting motion, so that the forklift gantry structural member 500 on the overturned conveying platform 100 can be stably received.

As shown in fig. 1 to 3, the material receiving platform 400 includes two material receiving jacking mechanisms 410, and the two material receiving jacking mechanisms 410 can perform spacing adjustment along a direction parallel to the axial direction of the turning shaft of the positioner 200; the jacking receiving mechanism 410 comprises a jacking cylinder 411 and a receiving plate 412 installed at the free end of the jacking cylinder 411, the jacking cylinder 411 is, as the name suggests, a cylinder capable of lifting in the vertical direction, the receiving plate 412 is installed at the free end of the jacking cylinder 411, that is, the receiving plate 412 can lift under the action of the jacking cylinder 411, the top surface of the receiving plate 412 is of a rectangular structure, and the length direction of the receiving plate is consistent with the moving direction of the mobile trolley 300, so that the fork truck gantry structural member 500 can be received; backing plates 4121 are respectively mounted at two end portions of the top surface of the receiving plate 412 in the length direction, limiting blocks 4122 are respectively mounted at two end portions of the top surface of the backing plate 4121 in the length direction of the receiving plate 412, the position of the forklift mast structural member 500 can be limited by the aid of the backing plates 4121 and the limiting blocks 4122, and the forklift mast structural member 500 is prevented from falling off from the receiving plate 412 under the action of inertia and the like, wherein the inertia refers to the inertia existing on the forklift mast structural member 500 when the mobile trolley 300 starts to move; meanwhile, in order to improve the stability of the material receiving plate 412 in the lifting process, a guide rod 420 can be installed at the bottom of the material receiving plate, the axial direction of the guide rod 420 is the same as the telescopic direction of the jacking cylinder 411, and the bottom end of the guide rod is connected with the cylinder barrel of the jacking cylinder 411 in a sliding mode.

As shown in fig. 1, the conveying platform 100 mainly comprises a roller conveyor 110 and a clamping device 120, the roller conveyor 110 can convey the forklift mast structure 500 to a proper position, and the clamping device 120 is installed on the roller conveyor 110 and can clamp the forklift mast structure 500 after the roller conveyor 110 conveys the forklift mast structure 500 to a proper position, so that the forklift mast structure 500 is prevented from falling off the conveying platform 100 in the process of overturning the conveying platform 100, and the actual safety performance is improved.

As shown in fig. 4, the clamping device 120 includes a housing 123 mounted on the roller conveyor 110 and having a length direction perpendicular to the conveying direction of the roller conveyor 110, two pushing cylinders 121 mounted inside the housing 123 and capable of extending and retracting along the length direction of the housing and symmetrically distributed, and two tensioning claws 122 respectively mounted at free ends of the two pushing cylinders, wherein top ends of the tensioning claws penetrate through an inner top wall of the housing 123 and extend to above the housing; the two pushing cylinders 121 are installed in a manner that free ends of the two pushing cylinders 121 face the inner middle position of the shell 123, when in actual clamping operation, the two pushing cylinders 121 are firstly utilized to drive the two tensioning claws 122 to approach to the middle until the distance between the two tensioning claws 122 reaches the minimum position, after the forklift gantry structural member 500 is moved to a proper position, the two pushing cylinders 121 are utilized to drive the two tensioning claws 122 to gradually move away until the two tensioning claws 122 abut against two channel steels of the forklift gantry structural member 500 respectively, and clamping and fixing of the forklift gantry structural member 500 are achieved.

As shown in fig. 1, the roller conveyor 110 is fixedly connected with the turning shaft of the positioner 200, and meanwhile, in order to improve the stability of the roller conveyor 110 in the turning process and reduce the pressure borne by the turning shaft of the positioner 200, a support 210 is arranged at one end of the roller conveyor 110 far away from the positioner 200, and the roller conveyor 110 is rotatably connected with the support 210, so that the gravity of the roller conveyor 110 can be distributed to the positioner 200 and the support 210, and the phenomenon that the turning shaft of the positioner 200 is bent and deformed is avoided; the roller conveyor 110 may be rotatably connected to the support 210 by bearings or by other structures capable of rotatably connecting.

As shown in fig. 1 and fig. 2, the moving trolley 300 includes a base 310, two slide rails 320 fixedly disposed relative to the base of the positioner 200 and parallel to each other, and a driving assembly 330 for driving the base 310 to slide on the two slide rails 320, wherein the bottom end of the jacking material receiving mechanism 410 is slidably mounted on the base 310 through two linear guide rails 350, and is locked in position on the base 310 through a locking assembly 340.

The base 310 is of a square frame structure, the two linear guide rails 350 are respectively installed on two opposite side surfaces of the inner wall of the base 310, the length direction of the linear guide rails 350 is parallel to the axial direction of the turning shaft of the positioner 200, and therefore the distance between the two jacking material receiving mechanisms 410 can be adjusted along the direction parallel to the axial direction of the turning shaft of the positioner 200.

The driving component 330 includes a dual-output-shaft speed-reducing motor 331, two transmission shafts 332 and two driving rollers 333, wherein the dual-output-shaft speed-reducing motor 331 can rotate in a forward and reverse direction and is installed on one end of the base 310 along the sliding direction thereof, and two output shafts of the dual-output-shaft speed-reducing motor 331 respectively face the two sliding rails 320, the two output shafts of the dual-output-shaft speed-reducing motor 331 are respectively and fixedly connected with the two transmission shafts 332 through a coupler, one ends of the two transmission shafts 332 far away from the dual-output-shaft speed-reducing motor 331 are respectively and fixedly connected to the two driving rollers 333, and the two driving rollers 333 are respectively and rollingly connected to the two sliding rails 320, and meanwhile, in order to reduce the friction force of the base 310 in the sliding process along the sliding rails 320, two driven rollers can be rotatably installed on one end of the base 310 far away from the dual-output-shaft speed-reducing motor 331 through a structure such as a bearing 334, and the like, and the two driven rollers 334 are respectively and rollingly connected to the two sliding rails 320, so that the driving rollers 331 can drive the driving rollers 333 to rotate when the dual-output-shaft speed-reducing motor 331 is started, and thereby the base 310 can move along the sliding rails 320; the power supply circuit of the double-output-shaft speed reducing motor 331 can be arranged on the drag chain 335, and then the drag chain 335 can normally operate by matching with the groove plate 336 matched with the drag chain 335, and the advantage of using the drag chain 335 is that the condition that the power supply circuit of the double-output-shaft speed reducing motor 331 is damaged or wound together when dragging the ground can be prevented.

As shown in fig. 5, the locking assembly 340 includes a fixing plate 341 installed inside the base 310 and horizontally disposed, a bottom plate 342 installed at the bottom end of the material lifting and receiving mechanism 410, a stud 343 threaded through the bottom plate 342 and vertically disposed, and a handle 344 fixed at the top end of the stud 343, and the bottom end of the stud 343 can be pressed against the fixing plate 341 by rotating the handle 344; the two ends of the bottom plate 342 are respectively slidably mounted on the two linear guide rails 350, so that the material lifting and receiving mechanism 410 is slidably connected with the base 310, and due to the existence of the linear guide rails 350, a worker can manually adjust the position of the material lifting and receiving mechanism 410, and after the positions of the two material lifting and receiving mechanisms 410 are adjusted to appropriate positions, the stud 343 is driven to rotate on the bottom plate 342 by the handle 344, so that the stud 343 gradually moves downwards until the bottom end of the stud 343 is pressed on the fixed plate 341, and the position of the material lifting and receiving mechanism 410 is locked by friction force between the stud 343 and the fixed plate 341; preferably, a soft pad such as a rubber pad may be attached to the bottom end of the stud 343 to prevent rigid contact between the stud 343 and the fixing plate 341.

The novel using method comprises the following steps: moving the forklift mast structure 500 onto the roller conveyor 110, then starting the roller conveyor 110, adjusting the position of the forklift mast structure 500 to enable the forklift mast structure to be in a proper position, and then clamping the forklift mast structure 500 by using the clamping device 120 to enable the forklift mast structure to be fixedly connected with the roller conveyor 110, so as to prevent the forklift mast structure 500 from moving; then, firstly, the trolley 300 is ensured not to be under the roller conveyor 110, and the overturn of the roller conveyor 110 is ensured not to be shielded by the trolley 300, then the positioner 200 is used for driving the roller conveyor 110 to turn over for 180 degrees, the forklift mast structural part 500 which originally faces upwards on the roller conveyor 110 is turned over to be downwards, then, the distance between the two jacking receiving mechanisms 410 is adjusted according to the actual situation, so that the distance between the two jacking receiving mechanisms 410 is matched with the forklift portal structural member 500, the situation that the distance between the two jacking receiving mechanisms 410 is larger than the length of the forklift portal structural member 500 is avoided, then, the double-output-shaft speed reducing motor 331 is started to convert the electric energy into mechanical energy, the two driving rollers 333 are driven by the two transmission shafts 332 to roll on the two slide rails 320 respectively, then, the base 310 can move along the slide rails 320 by cooperating with the driven rollers 334 until the base 310 drives the two jacking receiving mechanisms 410 to move to a position right below the forklift mast structural member 500 at the moment, then, the jacking cylinder 411 is started to push the receiving plate 412 to move upwards until the two backing plates 4121 on the receiving plate 412 contact with the forklift gantry structure 500, then, the clamping of the clamping device 120 on the forklift gantry structure 500 is released, then the jacking cylinder 411 is used for driving the material receiving plate 412 to move downwards, the forklift gantry structure 500 at the moment slowly moves downwards along with the material receiving plate 412 under the action of gravity, stable receiving of the forklift gantry structure 500 is achieved, then the forklift gantry structure 500 is moved away from the position under the roller conveyor 110 through the matching of the double-output-shaft speed reducing motor 331, the driving roller 333 and the driven roller 334, the roller conveyor 110 is turned to the original position through the positioner 200 after the forklift gantry structure 500 is completed, and then the conveying operation of the next forklift gantry structure 500 can be carried out.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described above, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides an automatic commodity circulation conveying platform of fork truck portal structure spare which characterized in that includes:

the conveying platform (100) is used for supporting and clamping a forklift portal structural member;

the positioner (200) drives the conveying platform to turn 180 degrees;

the moving trolley (300) is arranged on the outer side of the conveying platform and can move to the position right below the conveying platform along the direction which is vertical to the axial direction of the turnover shaft of the positioner; and

connect material platform (400), set up on travelling car to can carry out elevating movement, be used for steadily receiving the fork truck portal structure on the conveying platform after the upset.

2. The automatic logistics conveying platform of forklift mast structure members as recited in claim 1, wherein: connect material platform (400) to include two jacking receiving mechanism (410), two jacking receiving mechanism can be along with the direction that the trip shaft axial direction of machine of shifting (200) parallels carries out the interval and adjusts.

3. The automatic logistics conveying platform of forklift mast structure members as recited in claim 2, wherein: the jacking material receiving mechanism (410) comprises a jacking cylinder (411) and a material receiving plate (412) installed at the free end of the jacking cylinder, and the length direction of the material receiving plate is consistent with the moving direction of the moving trolley (300).

4. The automatic logistics conveying platform of forklift mast structure members as recited in claim 3, wherein: backing plates (4121) are mounted at two ends of the top surface of the material receiving plate (412) along the length direction of the material receiving plate, and limiting blocks (4122) are mounted at two ends of the top surface of each backing plate along the length direction of the material receiving plate.

5. The automatic logistics conveying platform of forklift mast structure members as recited in claim 2, wherein: the movable trolley (300) comprises a base (310), two mutually parallel slide rails (320) which are fixedly arranged relative to the base of the positioner (200) and a driving assembly (330) for driving the base to slide on the two slide rails, wherein the jacking material receiving mechanism (410) is slidably mounted on the base (310) and is locked at the position of the jacking material receiving mechanism on the base through a locking assembly (340).

6. The automatic logistics conveying platform of forklift mast structure members of claim 5, wherein: the driving assembly (330) comprises a double-output-shaft speed reducing motor (331) which is installed on one end of the base (310) in the sliding direction and two output shafts of which respectively face the two sliding rails (320), and two driving rollers (333) which are fixedly connected with the two output shafts of the double-output-shaft speed reducing motor through two transmission shafts (332), wherein the two driving rollers are respectively connected onto the two sliding rails in a rolling manner.

7. The automatic logistics conveying platform of forklift mast structure members as recited in claim 1, wherein: the conveying platform (100) comprises a roller conveyor (110) and a clamping device (120) for clamping the forklift mast structure on the roller conveyor.

8. The automatic logistics conveying platform of forklift mast structure members as recited in claim 5, wherein: locking subassembly (340) including install fixed plate (341) inside and the level setting in base (310), install bottom plate (342) at jacking receiving mechanism (410) bottom, screw thread run through bottom plate (342) and along stud (343) and the handle (344) of fixing on stud (343) top that vertical direction set up, rotate handle (344), can make the bottom of stud (343) compress tightly on fixed plate (341).

9. The automatic logistics conveying platform of forklift mast structure members as recited in claim 7, wherein: the clamping device (120) comprises a shell (123) which is arranged on a roller conveyor (110) and is vertical to the conveying direction of the roller conveyor (110) in the length direction, two pushing cylinders (121) which are arranged inside the shell (123) and can stretch and retract along the length direction of the shell and are symmetrically distributed, and two tensioning claws (122) which are respectively arranged at the free ends of the two pushing cylinders, wherein the top ends of the tensioning claws penetrate through the inner top wall of the shell (123) and extend to the upper side of the shell.