134results about How to "Meet support needs" patented technology

The utility model belongs to the technical field of tunneling equipment, and particularly provides a rear support of a heading machine and the heading machine. The rear support of the heading machine comprises an installation base body and a vertical oil cylinder, the vertical oil cylinder is hinged to a supporting arm assembly, the supporting arm assembly comprises a supporting arm installation base and two supporting oil cylinders stretching out and drawing back in the left-right direction, the fixed ends of the supporting oil cylinders are connected to the supporting arm installation base, the stretching ends of the supporting oil cylinders are connected with supporting bodies, and the stretching ends are arranged in a back-to-back mode. The supporting body is provided with a supporting face used for being attached to the wall of a tunnel. The heading machine comprises the heading machine rear support. The rear support supports the tunnel walls on the left side and the right side of the tunnel, slag removal operation at the bottom of the tunnel is not affected, arrangement of a slag removal device is not affected, and the length of the heading machine is convenient to control. And meanwhile, the vertical oil cylinder does not need to be frequently adjusted during steering, and the efficiency is high.

The utility model relates to the technical field of supporting structures in a foundation pit, and discloses a supporting structure used in the foundation pit and convenient to disassemble and assemble, which comprises a supporting plate, a fixed seat is fixedly arranged on the inner side of the supporting plate, a sliding block is movably arranged in the fixed seat, two rotating blocks are movably arranged in the sliding block, and the two rotating blocks are fixedly arranged on the supporting plate. And a threaded rod is fixedly mounted at one end of one rotating block. Compared with a traditional structure, the structure has the advantages that the threaded rod and the threaded sleeve are convenient to disassemble and assemble through the cooperation between the fixed seat and the sliding block, and meanwhile, the two supporting plates are convenient to support through the cooperation between the threaded rod and the threaded sleeve; through the connection mode of the threaded rods and the threaded sleeves, the supporting plates are rapidly and accurately connected, complex installation and tedious disassembly steps in a traditional supporting mode are avoided, and the construction period is greatly shortened.

The present invention provides a strip steel rolling welding device, comprising a strip steel limiting assembly, a strip steel power assembly, a strip steel outer edge shaping assembly, a rolling device, a round tube heating assembly, an opening shaping assembly, a straight seam welding assembly and a weld scar cutting assembly, which are sequentially arranged. The strip steel outer edge shaping assembly is used to cut the two side edges of the strip steel into oppositely arranged grooves. The strip steel rolling welding device described in the present invention can cut the two side profiles of the strip steel into opposite grooves through the strip steel outer edge shaping assembly. After rolling, the two grooves fit together, and then the fitting grooves are melt-welded by the straight seam welding assembly. During welding, the strip steel body located at the upper groove position is used to release the welding material for molten welding, and the strip steel body located at the lower groove position is used to receive the molten welding material. The molten welding material is self-gathered in the weld seam by gravity and surface tension to ensure the welding quality, and can reduce or avoid the weld scar inside the welded pipe, thereby improving the forming quality.

The utility model provides a deep foundation pit supporting structure, which relates to the technical field of foundation pit supporting and comprises an external Larsen steel sheet pile and a steel enclosing purlin positioned on the inner side of the Larsen steel sheet pile, and the inner side of the steel enclosing purlin is connected with a steel supporting piece through a steel cushion box; a plurality of layers of steel enclosing purlins are horizontally arranged, each layer of steel enclosing purlins is connected with a layer of steel supporting pieces, four sets of steel supporting pieces are arranged on each layer of steel enclosing purlins, and a set of steel supporting pieces is connected between the steel enclosing purlins on the inner sides of every two adjacent Larsen steel sheet piles. Each set of steel supporting pieces comprises at least two steel supporting pieces, each set of steel supporting pieces comprises a long support and a plurality of short supports, and the long supports and the short supports of each set of steel supporting pieces are arranged in parallel. The utility model has the beneficial effects of reasonable design, simple structure, safety and reliability, and can provide reliable support for different soil layers, improve the supporting effect and reduce the construction difficulty and cost.

The utility model provides an air jet loom supporting and blocking mechanism, which relates to the technical field of air jet loom accessories, and comprises a supporting and blocking seat, a supporting and blocking thorn shaft and a supporting rod, the supporting and blocking thorn shaft comprises a thorn shaft rod, a rubber sleeve and a thorn ring mechanism, and the thorn ring mechanism comprises a thorn ring sleeve, a plurality of thorn ring breast boards and a plurality of thorn rings. The multiple thorn ring breast boards are rotationally connected to the outer side of the thorn ring sleeve in a sleeving mode, the multiple thorn ring breast boards are arranged on the outer side of the thorn ring sleeve in a sleeving mode and arranged between every two adjacent thorn ring breast boards, rotating rods extend from the left side and the right side of the thorn ring sleeve, rotating holes are formed in the two sides of each thorn ring breast board, and the thorn ring breast boards are rotationally connected to the rotating rods. An adjusting gear is fixedly arranged on the inner wall of the thorn ring breast board, an adjusting rack is installed on the outer wall of the thorn ring sleeve in a sliding mode, and the adjusting rack is meshed with the adjusting gear. The barbed ring breast boards can rotate and incline by adjusting the racks, so that the inclination angle of the barbed rings is adjusted, and the external supporting force of the barbed rings on the fabric is changed.

The invention relates to a contrast enhancement type optical fiber image inverter and a preparation method thereof. The preparation method comprises the following steps: drawing contrast enhancement type filter glass into a light absorption wire; matching the skin material glass tube with the core material glass rod, and drawing into a monofilament and a round white filament; the drawn monofilaments are arranged into a primary composite rod with an orthohexagonal cross section, and triangular holes of the primary composite rod are evenly filled and inserted with light absorption filaments and round white filaments; drawing the combined primary composite rod into a primary multifilament; arranging the primary multifilaments into secondary composite rods with orthohexagonal cross sections, drawing the secondary composite rods into secondary multifilaments, cutting the secondary multifilaments in a fixed-length manner, and arranging the secondary multifilaments into rows of screen plate sections; and carrying out hot melt pressing forming and torsion forming to obtain the contrast enhancement type optical fiber image inverter. The contrast-enhanced optical fiber image inverter prepared by the method has the advantages of high resolution, high contrast, clear imaging, uniform transmittance, excellent internal quality and the like.

The heightening frame and the combined storage structure thereof are characterized in that the heightening frame comprises a heightening frame body, a basic heightening module and a functional module, the heightening frame body is provided with a top face bearing part and a bottom face mounting part, and at least one set of linearly-distributed inserting guide rails are arranged on the bottom face of the top face bearing part in the length direction; the bottom surface mounting part is provided with a plurality of second butt joint structures; the basic heightening module is composed of supporting assemblies, and the supporting assemblies are matched through butt joint structures and connecting structures to achieve supporting and vertical stacking extension. The functional modules are matched with the guide rails through the sliding blocks, and sliding adjustment and forward and reverse posture switching along the bottom face of the body are achieved. According to the combined storage structure, the two main bodies are in butt joint in an upright and inverted mode to form the containing gap. Flexible layout and form switching of functional modules are achieved, the height can be modularly adjusted, a double-layer storage space is constructed through the combined storage structure in a combined mode, and the structural strength and the space utilization rate are improved.

The utility model provides an automatic welding equipment of self -adaptation control has solved the problem of lower welding efficiency of automatic welding platform to steel frame. The utility model discloses a welding platform, the bottom fixed of welding platform is equipped with a plurality of branch legs, is equipped with detachable work piece fixed platform on the welding platform, still be equipped with the welding device of left and right translation on the welding platform, and the welding device is located the rear of work piece fixed platform, work piece fixed platform includes the rectangular frame of head -to -tail connection, and the top of rectangular frame is paved with a plurality of support unit boards that are set up and the left and right position is adjustable, support unit board is used to support the outer frame and a plurality of inner struts of being welded, is equipped with the first positioning member and second positioning member of adjustable position on support unit board, and the first positioning member is used to compress tightly fixed outer frame on support unit board, and the second positioning member is used to compress tightly fixed inner struts on support unit board.

The utility model relates to the technical field of petrochemical container machining corollary equipment, in particular to a petrochemical container bottom welding tool which comprises a supporting base, a supporting plate, a connecting protrusion, a guide sliding rod, a connecting strip, an electric push rod, a supporting frame, a connecting shaft, a supporting roller, a connecting sleeve, a supporting strip and supporting legs. The lower surfaces, close to the two ends, of the supporting plate are fixedly connected to the upper ends of the supporting bases correspondingly, the connecting protrusions are fixedly connected to the surfaces of the two sides of the end of the supporting plate correspondingly, vertical connecting holes are formed in the middles of the connecting protrusions, and the guide sliding rods are slidably connected into the connecting holes of the connecting protrusions correspondingly. The two ends of the connecting strip are fixedly connected to the upper ends of the two corresponding guide sliding rods at the same end of the supporting plate correspondingly, the electric push rods are fixedly connected to the upper surfaces, close to the ends, of the supporting plate correspondingly, and the welding device has the advantages of being good in flexibility, convenient to move and adjust, capable of effectively improving the welding convenience degree and good in operation stability.

The utility model aims to solve the problems that the existing reactor is large in use volume, high in cost and incapable of being combined for use. The small combinable reactor structure comprises a main frame and a reaction module, the main frame is hollow, and the reaction module is arranged in the main frame; the bottom of the main frame is provided with a first air inlet and outlet for air circulation, and the top of the main frame is provided with a second air inlet and outlet. Closed plates are arranged on the side surfaces of the middle part of the main frame, and the middle part of the main frame is used for arranging a reaction module; the first air inlet and outlet in the bottom of the main frame comprises three first air openings, and the three first air openings are located in the three side faces of the bottom of the main frame correspondingly. A connecting structure for connecting first air ports of other reactors is also arranged on the first air port; through the combined connection of the reactors, the purification requirements of flue gas with different displacements can be met, and the size of a single reactor is small.

The utility model discloses an auxiliary supporting device for building floors, which comprises a main supporting pipe, an auxiliary supporting pipe and an auxiliary supporting pipe, the inclined supporting pipes are arranged at the center of the outer side surface of the main supporting pipe and are uniformly distributed in the horizontal direction; the adjusting sleeve is arranged below the U-shaped shaft; the cable-stayed supporting plate is movably mounted above the outer side surface of the main supporting pipe; the lower supporting pipe is arranged below the outer side surface of the main supporting pipe; and the arc-shaped bevel protractor is arranged below the outer side surface of the main supporting pipe. By means of connection of the inclined supporting pipes and the inclined pulling supporting plates, the second top supporting plate and the first top supporting plate are supported at the same time, the supporting area is increased, the number of the supporting pipes is reduced, and the supporting efficiency is guaranteed; the lower supporting pipe and the inclined supporting pipe are shored through adjustment of the adjusting sleeve and the adjusting screw rod, the supporting stability of the inclined supporting pipe can be improved, the situation that the inclined supporting pipe is bent due to too large stress is avoided, the whole body can be supported through the lower supporting pipe, and the stability of contact with the ground is improved.

The utility model discloses a bearing seat and tracking support relates to photovoltaic power generation technical field, and this support includes main beam, bearing seat, photovoltaic bearing and non -driven stand. Bearing seat is enclosed by the stamping cover plate and stamping bearing base of mutual adaptation, and the inside holds photovoltaic bearing, and the stamping bearing base is combined by two same stamping sub -units, and the bottom is connected with non -driven stand. Photovoltaic bearing is integral type spherical high molecule structure, and the sleeve joint is in main beam outside, and its spherical outer contour is adapted with bearing seat inner wall, can realize main beam angle adjustment, and the stamping sub -unit has H type and Y type two, is connected with non -driven stand wing plate or directly with waist board through corbel adapter, and the bearing seat axial both ends are equipped with flanging, and the base is equipped with the strip. The utility model discloses through stamping structure reduces the cost, shortens the period, and realizes flexible angle -adjusting with the help of spherical bearing, and the adaptability is strong, is applicable to large -scale photovoltaic power station.

The present invention relates to the technical field of municipal pipeline construction, and in particular to a road rainwater and sewage pipeline laying device, comprising a support gate seat located on a groove, a lifting mechanism is arranged under the support gate seat, the lifting mechanism comprises lifting frames arranged on the left and right sides, a front supporting mechanism is arranged on the front side of the lifting frame, a sliding support is arranged between the two lifting frames, the sliding support comprises a slide plate, a rear supporting mechanism is arranged above the slide plate, and a scraping mechanism is arranged below the slide plate opposite to the rear supporting mechanism; a laser transmitter and a laser receiver are arranged at the left and right ends of the rear side of the slide plate; the distance between the laser transmitter and the laser receiver relative to the scraping mechanism is equal to twice the flared length of the pipeline. The laser transmitter and the laser receiver are used as positioning, the lifting frame drops the pipeline into the groove, and the scraping mechanism scrapes the crushed sand and gravel into a shallow groove. When laying the pipeline, there is no need for a crane to lift the pipeline into the groove, and there is no need for manual trenching and auxiliary alignment, so the laying efficiency is improved and the degree of automation is high.

A universal threshold beam loading and unloading carrier comprises a positioning mechanism arranged on a base frame, the positioning mechanism comprises a first supporting frame, a second supporting frame, a third supporting frame, a fourth supporting frame, a first pressing frame and a second pressing frame, the first supporting frame, the second supporting frame, the third supporting frame and the fourth supporting frame are identical in structure, and each supporting frame comprises a first support and a linkage block which are installed on the base frame. A plurality of supporting blocks are hinged in the height direction at intervals, limiting rods are arranged below the inward ends of the corresponding supporting blocks, linkage blocks are arranged between every two adjacent supporting blocks, the lower ends of the linkage blocks are hinged to the outward ends of the supporting blocks on the lower layer, and limiting grooves are formed in the upper ends of the linkage blocks and hinged to the outward ends of the supporting blocks on the upper layer. Each pressing frame comprises a second support installed on the machine frame, the second supports vertically extend upwards, a plurality of pressing blocks are arranged in the height direction at intervals, and the extending ends of the pressing blocks are elastic sections. The automatic loading and unloading device is simple in structure and low in machining cost, can realize automatic loading and unloading of a plurality of doorsill beams, is suitable for the doorsill beams of multiple specifications, and meets the transportation requirements of logistics enterprises.

The utility model discloses a kind of milling machine workbench positioning devices of replaceable clamp, including workbench, multiple groups of sliding slots are opened in the workbench, two groups of block body one and two groups of block body two are slidably connected in part sliding slot, multiple groups of block body two are respectively adhered to corresponding block body one, multiple groups of block body two one end are all thread connected with stud, multiple groups of plate body are equipped on the workbench, and multiple groups of plate body are all opened with groove body.The utility model moves two groups of block body along sliding slot, can drive plate body to adjust to with clamp bottom mounting seat matching position, the clamp of different size, mounting position is adapted, and the compatibility of multiple specifications is improved.Moving plate body makes one end to clamp mounting seat, the other end to pad block, form bidirectional support, even power transmission avoids clamp single-point stress or suspended instability, enhances processing stability.Pad block stepped design provides multiple height selection, without frequent replacement pad block, reduce downtime waiting, and the applicability is wider.

The present invention discloses an assembled moisture-proof floor with an embedded assembly structure, which belongs to the technical field of assembled floors, and includes a floor body, a moisture-proof mechanism is fixedly connected inside the floor body, a clamping mechanism is provided on both sides of the inner cavity of the floor body, and the floor body is connected to a connecting mechanism through the clamping mechanism, and a limiting mechanism is provided on both sides of the floor body, and the limiting mechanism is fitted with one side of the connecting mechanism. In the present invention, by setting a clamping mechanism, the waterproof effect of the fixing seat and the fixing rod is guaranteed, and the durable life of the assembly components is guaranteed, and the floor body is assembled by screwing the clamping plate into the limited assembly, so that the floor body can be quickly and conveniently disassembled, so that the influence of water immersion can be significantly reduced while the floor body is quickly assembled, and the reusability after disassembly is improved, so as to meet the sustainable use needs of the assembled floor.

The utility model relates to the technical field of mining machinery intelligent interaction equipment, in particular to a support convenient for adjusting mining machinery intelligent interaction equipment, which comprises a base, a negative pressure sucker arranged at the bottom of the base, a hovering damping rotating shaft part in threaded connection with the top of the base, and a sleeve hinged to the top of the hovering damping rotating shaft part. A square telescopic rod is slidably connected into the sleeve, a movable groove is vertically formed in the bottom of the square telescopic rod, a rotary knob is rotatably connected to the side wall of the sleeve, a lead screw driven by the rotary knob to rotate is arranged in the sleeve, the lead screw is sleeved with a threaded block in a threaded mode, the threaded block is fixed into the movable groove, and the top end of the square telescopic rod is in threaded connection with a universal ball assembly. The universal ball assembly is in threaded connection with a connecting rod, and the other end of the connecting rod is fixedly connected with a magnetic suction plate. The supporting device is simple in structure and convenient to operate, the supporting requirements of different types of artificial intelligence interaction equipment can be met, and the height and the angle can be freely adjusted.

The utility model discloses a positioning device for testing the bearing capacity of a well lid, and relates to the technical field of well lid testing tools. The device structurally comprises a cylindrical supporting table and a plurality of supporting nails installed on the cylindrical supporting table. The upper end of the cylindrical supporting table is provided with a plurality of guide grooves formed in the radial direction of the cylindrical supporting table, and the guide grooves are of inverted-T-shaped structures. The upper surface of the cylindrical supporting table is provided with a circular ring identification groove set coaxial with the cylindrical supporting table. By means of the cylindrical supporting table and the supporting nails installed on the cylindrical supporting table, for a special-shaped well lid with the center of the round lower end protruding, the supporting nails can stably move along the guide grooves, the positions of the supporting nails can be adjusted according to well lids with different diameters, the top face of the supporting column body is flush with the flush bottom face below the well lid, and even supporting force is provided; for the special-shaped well lid with the supporting nails arranged below, the supporting nails can be effectively supported according to the distribution and arrangement of the supporting nails and the large-area position where the supporting nails are staggered, the supporting and testing requirements of various special-shaped well lids can be met, and wide applicability is achieved.

The utility model discloses a combined adjustable cable support which comprises a support body, the rear side of the support body is fixedly connected with a shell, the outer portion of the shell is fixedly connected with a shell plate, the interior of the shell plate is slidably connected with a plurality of clamping blocks, one end of each clamping block is fixedly connected with a second sliding block, and the other end of each clamping block is fixedly connected with a second sliding block. Two first connecting rods are slidably connected to the interior of the second sliding block, and two fixing blocks are fixedly connected to the two sides of each first connecting rod. By means of the structure, the first sliding block drives the third rack in the first sliding block to move, so that a third gear at the bottom rotates, the third rack at the bottom is driven to move, a clamping block outside the second sliding block of the first sliding block moves towards the middle, a support of the first sliding block is fixed to a designated position, and therefore tedious manual fixing operation is not needed; and the installation efficiency is greatly improved. A constructor can quickly fix the support only by pressing a button or through a remote control device, and manpower and time cost are saved.

The utility model discloses a supporting tool for a large aircraft body. The supporting tool comprises a bracket assembly and a supporting lifting platform. The bracket assemblies are used for supporting different parts of the bottom of a machine body, and the two ends of each bracket assembly are detachably connected with the corresponding supporting lifting platform; when the bracket assemblies are fixedly connected with the supporting lifting platforms and supported and fixed to the bottom of the machine body, the machine body is suspended. The utility model has the characteristics of compact structure, convenience in disassembly and assembly, high structural strength, high turnover utilization rate and the like, and meets the support and transfer requirements of the large aircraft fuselage.

The invention discloses a hydraulic lifting oil cylinder supporting and adjusting device, and relates to the field of hydraulic lifting oil cylinder machining, the hydraulic lifting oil cylinder supporting and adjusting device comprises a supporting frame, the top of the supporting frame is movably connected with a bottom mounting assembly, and the two ends of the top of the bottom mounting assembly are symmetrically and movably connected with mounting frames; connecting blocks are symmetrically and movably connected to the two ends of the right side of the top of the supporting frame, supporting columns are symmetrically installed at the bottoms of the two connecting blocks, connecting columns are installed on the outer walls of the supporting columns, clamping blocks are inserted into the side edges of the supporting columns, supporting bases are arranged at the tops of the connecting columns, and adjusting assemblies are symmetrically installed in the centers of the left sides of the two top mounting assemblies. According to the supporting and adjusting device for the hydraulic lifting oil cylinder, the supporting and adjusting device can be matched with hydraulic lifting oil cylinders of various sizes for installation, the device can be adjusted according to the installation position and angle of the hydraulic lifting oil cylinder, therefore, the supporting effect on the hydraulic lifting oil cylinder can be effectively improved, and the working efficiency of the hydraulic lifting oil cylinder can be guaranteed.

The utility model discloses a foundation pit supporting frame, and relates to the technical field of foundation pit supporting. The device comprises a cross beam, the two ends of the cross beam are fixed to the inner wall of a foundation pit, connecting plates are welded to the two sides of the bottom of the cross beam, supporting columns are welded to the two sides of the bottoms of the connecting plates, bases are welded to the bottom ends of the supporting columns, reinforcing mechanisms are arranged on the inner wall of the cross beam, and supporting mechanisms are arranged on the outer surfaces of the supporting columns. When the supporting column needs to be supported, the telescopic sleeve rod is pulled to drive the supporting base to move, so that the supporting base abuts against the inner bottom wall of the foundation pit, the supporting column can be effectively supported, the supporting mode is simple and practical, the stability and safety of the supporting column can be ensured, good conditions are provided for subsequent engineering construction, and the supporting column is convenient to use. And meanwhile, certain flexibility is achieved, and the angle of the telescopic sleeve and the length of the telescopic sleeve rod can be adjusted according to actual needs so as to meet the supporting requirements in different scenes.

The invention discloses an engineering pipeline construction supporting device, and relates to the technical field of pipeline supporting. Comprising two bottom plates, supporting assemblies are arranged at the upper ends of the two bottom plates, the two bottom plates are rotationally connected through a hinge, a connecting rod is fixedly connected to the side wall of one bottom plate, a connecting groove matched with the connecting rod is formed in the side wall of the other bottom plate, the connecting rod is inserted into the connecting groove in a sliding mode, and the connecting rod is connected with the connecting groove in a sliding mode. A first locking bolt in threaded connection with the other bottom plate is arranged at the upper end of the other bottom plate in a penetrating mode, extends into the connecting groove and abuts against the connecting rod. According to the pipeline supporting device, a pipeline can be stably clamped, the supporting stability of the pipeline is guaranteed, the supporting requirements of different heights of the pipeline and the supporting requirements of different included angles of the pipelines on the two sides can be met, and the applicability is good.

The invention discloses a paste filling material distribution pipe fixing device, and belongs to the technical field of material distribution pipe fixing.The paste filling material distribution pipe fixing device comprises two mounting boxes, clamping assemblies used for clamping material distribution hoses are arranged on the mounting boxes, and distance adjusting assemblies connected with the clamping assemblies are arranged on the mounting boxes; the sides, close to each other, of the clamping assemblies are movably connected with a protection assembly, the protection assembly is arranged on the outer side of the cloth hose, the ends, close to each other, of the mounting boxes are connected with an angle adjusting assembly, and the angle adjusting assembly is used for fixing the included angle between the two mounting boxes. The clamp has the advantages of being flexible in clamping, convenient to operate, flexible in angle adjustment, stable in limiting, reliable in protection, simple in structure, simple, convenient and practical.

The utility model discloses a kind of plate shearing machines for steel fireproof door processing, including processing table, shearing assembly and guiding support device;The utility model is provided with guiding support device in processing table inner cavity, by bracket is unfolded from the inside of storage cavity and is turned over forward, then T type insert bar is separated with No. 2 slot movement, guiding frame can be taken out from processing table inner cavity, subsequently T type insert bar is slidably inserted with No. 1 slot, guiding frame is erected in bracket top, and guiding frame is butt joint with processing table, finally hasp and clasp hook are connected, guiding frame and processing table establish installation connection, to complete the assembly of guiding support device, guiding frame can provide guiding support for plate by guide wheel, satisfy the support demand of plate, without additional supporting facilities, function is more perfect, convenient transportation shifts.

The application relates to a novel body position pad, and belongs to the technical field of medical devices. The novel body position pad comprises an external wrapping piece and an internal fluid layer. The external wrapping piece comprises a first wrapping layer, a second wrapping layer and a third wrapping layer. The first wrapping layer is flexible. The second wrapping layer is arranged between the first wrapping layer and the third wrapping layer. The second wrapping layer supports the first wrapping layer and the third wrapping layer. The first wrapping layer and the third wrapping layer are both waterproof. The first wrapping layer and the third wrapping layer can isolate air. The external wrapping piece is arranged to form a containing cavity. The internal fluid layer is filled in the containing cavity. The internal fluid layer is flowable. The application can improve the problem that the shaping effect of the body position pad is not easy to maintain.