CN112647697A

CN112647697A - Construction platform for housing construction engineering

Info

Publication number: CN112647697A
Application number: CN202011562076.5A
Authority: CN
Inventors: 刘汉景; 刘超; 李镇麟; 赵亚峰; 陈文潮
Original assignee: China Railway Tianfeng Construction Engineering Co Ltd
Current assignee: China Railway Tianfeng Construction Engineering Co Ltd
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2021-04-13
Anticipated expiration: 2040-12-25
Also published as: CN112647697B

Abstract

The application relates to a construction platform for house building engineering, which comprises a bottom plate and a lifting platform arranged above the bottom plate, wherein a lifting mechanism for driving the lifting platform to lift is arranged between the bottom plate and the lifting platform, a placing disc is rotatably connected above the lifting platform, and a rotating mechanism for driving the rotating disc to rotate is arranged between the lifting platform and the bottom plate; the lifting mechanism and the rotating mechanism share one driving assembly. The tool has the effect of facilitating workers to take tools and construction materials.

Description

Construction platform for housing construction engineering

Technical Field

The application relates to the technical field of building construction, in particular to a construction platform for house building engineering.

Background

At present, building construction refers to production activities in the engineering construction implementation stage, and is a construction process of various buildings, or a process of changing various lines on a design drawing into a real object at a specified place.

At present, the great and setting for the over-and-under type of most construction platform homogeneous body type, its in-process that goes up and down can stack material and instrument on the platform, makes things convenient for the staff to use on construction platform.

In view of the above-mentioned related technologies, the inventor believes that due to the large construction platform, the worker needs to walk around when using materials or tools, and there is a defect that the working efficiency of the worker is reduced.

Disclosure of Invention

In order to make things convenient for the staff to take instrument and construction material, this application provides a building construction is construction platform for engineering.

The application provides a construction platform for housing construction engineering adopts following technical scheme:

a construction platform for house building engineering comprises a bottom plate and a lifting platform arranged above the bottom plate, wherein a lifting mechanism for driving the lifting platform to lift is arranged between the bottom plate and the lifting platform, a placing disc is rotatably connected above the lifting platform, and a rotating mechanism for driving the rotating disc to rotate is arranged between the lifting platform and the bottom plate; the lifting mechanism and the rotating mechanism share one driving assembly.

By adopting the technical scheme, the lifting mechanism is arranged, so that the lifting platform can be conveniently lifted; the rotating mechanism is arranged, so that the rotating disc can rotate conveniently, and the lifting mechanism and the rotating mechanism share one driving assembly, so that the cost is saved. The tool has the effect of facilitating workers to take tools and construction materials.

Preferably: a supporting shell is arranged between the lifting platform and the bottom plate, and the driving assembly comprises a driving motor arranged on the bottom wall in the supporting shell and a driving gear fixedly arranged on an output shaft of the driving motor; the output shaft of the driving motor and the driving gear rotate coaxially, a conversion assembly is arranged between the driving gear and the lifting mechanism and between the rotating mechanisms, and the conversion assembly is used for realizing conversion driving between the lifting mechanism and the rotating mechanisms.

Through adopting above-mentioned technical scheme, start the conversion subassembly, when conversion subassembly was located elevating system's position department, start driving motor, driving motor drives the conversion gear and rotates, and the conversion gear drives the conversion subassembly and rotates, and conversion subassembly drive elevating system starts, and elevating system drives the lift platform and goes up and down.

Preferably: the conversion assembly comprises a hydraulic cylinder hinged to the inner wall of the supporting shell and a conversion gear rotationally connected to the end part of a piston rod of the hydraulic cylinder through a rotating shaft, and the driving gear is meshed with the conversion gear; the position department of one side inner wall of support shell in the axis of rotation offers the spacing hole that is the arc setting, the axis of rotation slides and rotate connect in spacing hole.

Through adopting above-mentioned technical scheme, start the pneumatic cylinder, the pneumatic cylinder drives the conversion gear and removes along spacing hole, realizes the conversion in the middle of elevating system and slewing mechanism.

Preferably: the lifting mechanism comprises two spacing pipes which are fixedly arranged on the upper surface of the bottom plate and penetrate through the supporting shell, a spacing internal thread pipe which is rotatably connected with the spacing pipes, a vertical screw rod which is in threaded connection with the spacing internal thread pipe, and a lifting assembly which drives the spacing internal thread pipe to rotate; the lower surface of the lifting platform is fixedly connected with the upper ends of the two vertical screw rods.

By adopting the technical scheme, the hydraulic cylinder is started and drives the conversion gear to move; move to between lifting unit and the conversion gear, start driving motor, driving motor drives drive gear and rotates, and drive gear drives the conversion gear and rotates, and the conversion gear drives lifting unit and starts, and lifting unit drives spacing internal thread pipe and rotates, and the lift of spacing internal thread pipe drive vertical lead screw, vertical lead screw drive lift platform, the realization is to the lift drive of lift platform.

Preferably: the lifting assembly comprises lifting worm wheels fixedly arranged on the peripheral surfaces of the two limiting internal threaded pipes respectively, lifting worms meshed with the two lifting worm wheels respectively, and a lifting driven gear fixedly arranged at one end of one of the lifting worms; the lifting driven gear is meshed with the conversion gear, and the two lifting worms rotate coaxially.

By adopting the technical scheme, the hydraulic cylinder is started and drives the conversion gear to move; move to between lifting unit and the conversion gear, start driving motor, driving motor drives drive gear and rotates, and drive gear drives the conversion gear and rotates, and the conversion gear drives lift driven gear and rotates, and lift driven gear drives the lift worm and rotates, and the lift worm drives the lift worm wheel and rotates, and the lift worm wheel drives spacing internal thread pipe and rotates, and spacing internal thread pipe drives vertical lead screw lift, and vertical lead screw drives the lift of lift platform.

Preferably: the rotating mechanism comprises a positioning pipe which is fixedly arranged on the upper surface of the bottom plate and penetrates through the support shell, a positioning inner pipe which is rotatably connected with the positioning pipe, a square rod which penetrates through the positioning inner pipe and is connected with the positioning inner pipe in a sliding manner, and a rotating assembly which drives the positioning inner pipe to rotate; the upper end of the square rod is fixedly connected with the lower surface of the placing disc.

Through adopting above-mentioned technical scheme, rotating assembly drive the rotation of location inner tube, and the location inner tube drives square pole and rotates, and square pole drives and places the dish and rotate, realizes the drive to placing the dish.

Preferably: the rotating assembly comprises a rotating worm wheel fixedly arranged on the peripheral surface of the positioning inner pipe, a rotating worm meshed with the rotating worm wheel and a rotating driven gear fixedly arranged at one end of the rotating worm; the rotary driven gear is meshed with the conversion gear.

Through adopting above-mentioned technical scheme, the drive rotates driven gear, rotates driven gear and drives and rotate the worm and rotate, rotates the worm and drives and rotate the worm wheel rotation, rotates the worm wheel and drives the rotation of location inner tube, and the location inner tube drives square pole and rotates, and square pole drives and places the dish rotation, realizes the rotation drive to placing the dish.

Preferably: the lifting platform with be provided with flexible supporting component between the bottom plate, flexible supporting component including set firmly in the flexible outer tube of bottom plate and set firmly in the telescopic interior pole of terminal surface under the lifting platform, telescopic interior pole slide connect in flexible outer tube.

Through adopting above-mentioned technical scheme, flexible supporting component's setting strengthens the stability that lift platform reciprocated the in-process.

Preferably: the lower end face of the bottom plate is provided with brake universal wheels which are convenient for the whole device to move at the positions of four end angles of the bottom plate.

Through adopting above-mentioned technical scheme, the setting of brake universal wheel makes things convenient for whole construction platform's removal.

To sum up, the beneficial technical effect of this application does:

1. the lifting mechanism is arranged, so that the lifting platform can be conveniently lifted; the rotating mechanism is arranged, so that the rotating disc can rotate conveniently, and the lifting mechanism and the rotating mechanism share one driving assembly, so that the cost is saved. The tool has the effect of facilitating workers to take tools and construction materials;

2. starting the hydraulic cylinder, and driving the conversion gear to move by the hydraulic cylinder; moving the lifting assembly to a position between the lifting assembly and the conversion gear, starting a driving motor, driving the driving gear to rotate by the driving motor, driving the conversion gear to rotate by the driving gear, driving a lifting driven gear to rotate by the conversion gear, driving a lifting worm to rotate by the lifting driven gear, driving the lifting worm to rotate by the lifting worm, driving a limiting internal threaded pipe to rotate by the lifting worm gear, driving a vertical lead screw to lift by the limiting internal threaded pipe, and driving a lifting platform to lift by the vertical lead screw;

3. the driven gear is rotated in the drive, rotates driven gear and drives the rotation worm to rotate, rotates the worm and drives the rotation worm wheel to rotate, rotates the worm wheel and drives the rotation of location inner tube, and the location inner tube drives square pole and rotates, and square pole drives and places the dish and rotate, realizes the rotation drive to placing the dish.

Drawings

FIG. 1 is a schematic diagram of the overall structure of an embodiment of the present application;

FIG. 2 is a schematic structural view of the embodiment of the present application except for the bottom plate and the lifting platform;

FIG. 3 is a schematic view of a partial cross-sectional structure of a lifting mechanism in an embodiment of the present application;

FIG. 4 is a schematic diagram of a portion of an embodiment of the present application;

fig. 5 is a partial sectional structure diagram of the rotating mechanism in the embodiment of the present application.

Reference number legend, 1, bottom plate; 11. braking the universal wheel; 2. a lifting platform; 3. a lifting mechanism; 31. a limiting pipe; 311. a limiting annular groove; 32. a limiting internal threaded pipe; 321. a limiting convex ring; 33. a vertical lead screw; 34. a lifting assembly; 341. a lifting worm gear; 342. a lifting worm; 343. a lifting driven gear; 4. placing a tray; 41. a support pillar; 5. a rotating mechanism; 51. a positioning tube; 51. positioning the annular groove; 52. positioning the inner tube; 521. positioning the outer convex ring; 53. a square rod; 54. a rotating assembly; 541. rotating the worm gear; 542. rotating the worm; 543. rotating the driven gear; 6. a drive assembly; 61. a drive motor; 62. a drive gear; 7. a support housing; 71. a limiting hole; 72. a support plate; 73. a connecting rod; 8. a conversion component; 81. a hydraulic cylinder; 82. a switching gear; 9. a telescopic support assembly; 91. a telescopic outer tube; 92. a telescopic inner rod.

Detailed Description

The present application is described in further detail below with reference to figures 1-5.

The embodiment of the application discloses a construction platform for house building engineering, and the construction platform comprises a bottom plate 1, wherein the bottom plate 1 is rectangular, and brake universal wheels 11 are respectively arranged at the positions of four end corners of the lower end surface of the bottom plate 1, so that the whole construction platform can be conveniently moved; the lifting platform 2 is arranged above the bottom plate 1, four groups of telescopic supporting assemblies 9 are arranged between the bottom plate 1 and the lifting platform 2, and the four groups of telescopic supporting assemblies 9 are positioned at the positions, close to four end corners, of the bottom plate 1 and play a role in guiding and supporting the lifting of the lifting platform 2.

Each group of telescopic supporting components 9 comprises a telescopic outer tube 91 fixedly connected to the upper end surface of the bottom plate 1 and a telescopic inner rod 92 fixedly connected to the lower surface of the lifting platform 2, and the telescopic inner rod 92 is connected to the telescopic outer tube 91 in a sliding manner.

Referring to fig. 1 and 2, a lifting mechanism 3 for driving the lifting platform 2 to lift is arranged between the bottom plate 1 and the lifting platform 2; a plurality of support columns 41 are fixedly connected above the lifting platform 2, the support columns 41 are circumferentially arranged, a placing disc 4 for placing construction materials and tools is placed at the upper ends of the support columns 41, and a rotating mechanism 5 for driving the placing disc 4 to rotate is arranged between the lifting platform 2 and the bottom plate 1; and a supporting shell 7 is arranged between the lifting platform 2 and the bottom plate 1.

The lifting mechanism 3 comprises two spacing tubes 31 fixedly connected to the upper surface of the bottom plate 1 at intervals, a spacing internal thread tube 32 arranged on the spacing tube 31, a vertical screw 33 in threaded connection with the spacing internal thread tube 32, and a lifting assembly 34 for driving the spacing internal thread tube 32 to rotate.

Referring to fig. 2 and 3, the inner circumferential surface of the limiting tube 31 near the upper end thereof is provided with a limiting annular groove 311, the outer circumferential surface of the lower end of the limiting internally threaded tube 32 is fixedly connected with a limiting outward protruding ring 321, and the limiting outward protruding ring 321 is disposed in the limiting annular groove 311 and rotatably connected to the limiting annular groove 311, thereby realizing the rotational connection between the limiting tube 31 and the limiting internally threaded tube 32.

The supporting shell 7 is rectangular, the lower end of the supporting shell 7 in the length direction is provided with two via holes which are arranged at intervals, the two limiting pipes 31 respectively penetrate through the two via holes, and the supporting shell 7 is fixedly connected with the outer peripheral surface of each limiting pipe 31 at the position of each via hole; two through holes which are arranged at intervals and are used for the vertical screw rods 33 to pass through are formed in the upper end surface of the supporting shell 7, and the two vertical screw rods 33 are respectively and rotatably connected with the two through holes; the lower surface of the lifting platform 2 is fixedly connected to the upper ends of the two vertical screw rods 33.

Referring to fig. 2 and 4, the lifting assembly 34 includes lifting worm gears 341 fixedly connected to the outer peripheral surfaces of the two limit internal threaded pipes 32, lifting worms 342 rotatably connected to the two opposite inner walls of the support case 7 along the length direction thereof, and a lifting driven gear 343 fixedly mounted on the outer peripheral surface of one end of one of the lifting worms 342; the two lifting worms 342 are fixedly connected through a connecting rod 73, and each lifting worm 342 is meshed with the corresponding lifting worm 342.

Referring to fig. 1 and 4, the lifting driven gear 343 is driven to rotate, the lifting driven gear 343 drives the lifting worm 342 to rotate, the lifting worm 342 drives the lifting worm wheel 341 to rotate, the lifting worm wheel 341 drives the limiting internal thread pipe 32 to rotate, the limiting internal thread pipe 32 drives the vertical lead screw 33 to move up and down, the vertical lead screw 33 drives the lifting platform 2 to move up and down, and the lifting of the lifting platform 2 is realized.

Referring to fig. 3 and 5, the rotating mechanism 5 includes a positioning tube 51 fixedly connected to the upper surface of the base plate 1, a positioning inner tube 52 rotatably connected to the positioning tube 51, a square rod 53 slidably connected to the positioning inner tube 52, and a rotating assembly 54 for driving the square rod 53 to rotate.

The positioning pipe 51 is provided with a positioning annular groove 511 on the inner circumferential surface close to the upper end thereof, the outer circumferential surface of the lower end of the positioning inner pipe 52 is fixedly connected with a positioning outer convex ring 521, and the positioning outer convex ring 521 is arranged in the positioning annular groove 511 and is rotationally connected with the positioning annular groove 511, so that the rotational connection between the positioning pipe 51 and the positioning inner pipe 52 is realized; the positioning inner tube 52 is provided with a square hole, and the square rod 53 is connected to the positioning inner tube 52 in a sliding manner along the length direction of the positioning inner tube 52.

Referring to fig. 2 and 4, the lower end of the supporting shell 7 is provided with a fixing hole for the positioning tube 51 to pass through, the supporting shell 7 is fixedly connected with the outer peripheral surface of the positioning tube 51 at the position of the fixing hole, the upper end of the supporting shell 7 is provided with a rotating hole for the square rod 53 to pass through, the lifting platform 2 is provided with a through hole for the square rod 53 to pass through, and the square rod 53 passes through the end of the through hole and is fixedly connected with the lower surface of the placing tray 4.

The rotating assembly 54 includes a rotating worm gear 541 fixedly connected to the outer circumferential surface of the square bar 53, a rotating worm 542 rotatably connected to the inner wall of the support case 7, and a rotating driven gear 543 fixedly connected to the outer circumferential surface of the rotating worm 542; the lower end surface of the rotary worm gear 541 is attached to the upper end surface of the positioning pipe 51, and the rotary worm 542 is engaged with the rotary worm gear 541.

Referring to fig. 1 and 4, the driven gear 543 is driven to rotate, the driven gear 543 is rotated to drive the rotating worm 542 to rotate, the rotating worm 542 drives the rotating worm wheel 541 to rotate, the rotating worm wheel 541 drives the square rod 53 to rotate, and the square rod 53 drives the placing disc 4 to rotate, so that the placing disc 4 is driven to rotate.

The rotary driven gear 543 and the lifting driven gear 343 share one driving assembly 6, and a conversion assembly 8 is arranged among the rotary driven gear 543, the lifting driven gear 343 and the driving assembly 6; the driving assembly 6 comprises a driving motor 61 mounted on the bottom wall inside the supporting shell 7 and a driving gear 62 fixedly connected to the output shaft of the driving motor 61, and the rotating driven gear 543, the lifting driven gear 343 and the driving gear 62 are in the same plane.

The conversion assembly 8 comprises a hydraulic cylinder 81 which is hinged to the inner side wall of the support shell 7 through a hinge shaft, and a conversion gear 82 which is rotatably connected to the end part of a piston rod of the hydraulic cylinder 81 through a rotating shaft, wherein the side wall of the support shell 7 is provided with a limit hole 71, one end of the rotating shaft, which is far away from the conversion gear 82, is arranged in the limit hole 71 and is connected to the limit hole 71 in a sliding manner, and when the conversion gear 82 is positioned between the lifting driven gear 343 and the driving gear 62, the conversion gear 82 is meshed with both the lifting driven gear 343 and the driving gear 62, so as to realize; when the switching gear 82 is located between the rotation driven gear 543 and the drive gear 62, the switching gear 82 meshes with both the rotation driven gear 543 and the drive gear 62 for effecting rotational drive of the rotation driven gear 543.

The hydraulic cylinder 81 is started, the hydraulic cylinder 81 drives the conversion gear 82 to be connected to the limiting hole 71 in a sliding mode, and different driving of the rotary driven gear 543 and the lifting driven gear 343 is achieved.

Referring to fig. 2, a supporting plate 72 is disposed in the supporting shell 7, two rotating holes are formed in the supporting plate 72 at intervals, and the rotating worm 542 and the lifting worm 342 located on the same side are rotatably connected to the two rotating holes respectively.

The implementation principle of the construction platform for the house building engineering is as follows: moving the construction platform to a proper position, standing a worker on the lifting platform 2, and placing construction materials and tools on the placing disc 4; firstly, the hydraulic cylinder 81 is started, the hydraulic cylinder 81 drives the switching gear 82 to move, and when the switching gear 82 is positioned between the lifting driven gear 343 and the driving gear 62, the switching gear 82 is meshed with both the lifting driven gear 343 and the driving gear 62; then, the driving motor 61 is started, the driving motor 61 drives the driving gear 62 to rotate, the driving gear 62 drives the conversion gear 82 to rotate, the conversion gear 82 drives the lifting driven gear 343 to rotate, the lifting driven gear 343 drives the lifting worm 342 to rotate, the lifting worm 342 drives the lifting worm gear 341 to rotate, the lifting worm gear 341 drives the limiting internal threaded pipe 32 to rotate, the limiting internal threaded pipe 32 drives the vertical screw rod 33 to move up and down, the vertical screw rod 33 drives the lifting platform 2 to move up and down, and the lifting platform 2 is lifted and lowered; after the material is moved to a proper position, when a worker needs to take away materials and tools at a distance, the hydraulic cylinder 81 is started again, the hydraulic cylinder 81 drives the conversion gear 82 to move, and when the conversion gear 82 is located between the rotary driven gear 543 and the driving gear 62, the conversion gear 82 is meshed with both the rotary driven gear 543 and the driving gear 62; the driving motor 61 is started, the driving motor 61 drives the driving gear 62 to rotate, the driving gear 62 drives the conversion gear 82 to rotate, the conversion gear 82 drives the rotation driven gear 543 to rotate, the rotation driven gear 543 drives the rotation worm 542 to rotate, the rotation worm 542 drives the rotation worm wheel 541 to rotate, the rotation worm wheel 541 drives the square rod 53 to rotate, the square rod 53 drives the placing disc 4 to rotate, and the rotation driving of the placing disc 4 is achieved. The tool has the effect of facilitating workers to take tools and construction materials.

The embodiments of the present invention are preferred embodiments of the present application, and the scope of protection of the present application is not limited by the embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a building construction platform for engineering, include bottom plate (1) and set up in lift platform (2) of bottom plate (1) top, its characterized in that: a lifting mechanism (3) for driving the lifting platform (2) to lift is arranged between the bottom plate (1) and the lifting platform (2), a placing disc (4) is rotatably connected above the lifting platform (2), and a rotating mechanism (5) for driving the rotating disc to rotate is arranged between the lifting platform (2) and the bottom plate (1); the lifting mechanism (3) and the rotating mechanism (5) share one driving assembly (6).

2. The construction platform for housing construction engineering according to claim 1, characterized in that: a supporting shell (7) is arranged between the lifting platform (2) and the bottom plate (1), and the driving assembly (6) comprises a driving motor (61) arranged on the bottom wall of the supporting shell (7) and a driving gear (62) fixedly arranged on an output shaft of the driving motor (61); the output shaft of driving motor (61) with drive gear (62) coaxial core rotates, drive gear (62) elevating system (3) and be provided with conversion subassembly (8) between slewing mechanism (5), conversion subassembly (8) realize right elevating system (3) and the transition drive between slewing mechanism (5).

3. The construction platform for housing construction engineering according to claim 2, characterized in that: the conversion assembly (8) comprises a hydraulic cylinder (81) hinged to the inner wall of the support shell (7) and a conversion gear (82) connected to the end part of a piston rod of the hydraulic cylinder (81) in a rotating mode through a rotating shaft, and the driving gear (62) is meshed with the conversion gear (82); support one side inner wall of shell (7) and offer spacing hole (71) that are the arc setting in the position department of axis of rotation, the axis of rotation slides and rotate connect in spacing hole (71).

4. The construction platform for housing construction engineering according to claim 2, characterized in that: the lifting mechanism (3) comprises two spacing pipes (31) which are fixedly arranged on the upper surface of the bottom plate (1) and penetrate through the support shell (7) at intervals, a spacing internal thread pipe (32) which is rotatably connected to the spacing pipes (31), a vertical screw rod (33) which is in threaded connection with the spacing internal thread pipe (32), and a lifting assembly (34) which drives the spacing internal thread pipe (32) to rotate; the lower surface of the lifting platform (2) is fixedly connected with the upper ends of the two vertical screw rods (33).

5. The construction platform for housing construction engineering according to claim 4, characterized in that: the lifting assembly (34) comprises lifting worm gears (341) fixedly arranged on the outer peripheral surfaces of the two limit internal threaded pipes (32), lifting worms (342) respectively meshed with the two lifting worm gears (341) and a lifting driven gear (343) fixedly arranged at one end of one of the lifting worms (342); the lifting driven gear (343) is meshed with the conversion gear (82), and the two lifting worms (342) rotate coaxially.

6. The construction platform for housing construction engineering according to claim 2, characterized in that: the rotating mechanism (5) comprises a positioning pipe (51) fixedly arranged on the upper surface of the bottom plate (1) and penetrating through the support shell (7), a positioning inner pipe (52) rotatably connected to the positioning pipe (51), a square rod (53) penetrating through and slidably connected to the positioning inner pipe (52), and a rotating assembly (54) driving the positioning inner pipe (52) to rotate; the upper end of the square rod (53) is fixedly connected with the lower surface of the placing disc (4).

7. The construction platform for housing construction engineering according to claim 6, characterized in that: the rotating assembly (54) comprises a rotating worm wheel (541) fixedly arranged on the outer peripheral surface of the positioning inner pipe (52), a rotating worm (542) meshed with the rotating worm wheel (541), and a rotating driven gear (543) fixedly arranged at one end of the rotating worm (542); the rotary driven gear (543) is meshed with the switching gear (82).

8. The construction platform for housing construction engineering according to claim 1, characterized in that: lifting platform (2) with be provided with flexible supporting component (9) between bottom plate (1), flexible supporting component (9) including set firmly in the flexible outer tube (91) of bottom plate (1) and set firmly in telescopic interior pole (92) of terminal surface under lifting platform (2), slide in telescopic interior pole (92) connect in flexible outer tube (91).

9. The construction platform for housing construction engineering according to claim 1, characterized in that: the lower end face of the bottom plate (1) is provided with brake universal wheels (11) which are convenient for the whole device to move at the positions of four end angles of the bottom plate.