18 results about "Pre tension" patented technology

The invention relates to a welding center and method for platform machining, and belongs to the technical field of welding equipment. The device comprises a rack, a gantry frame is slidably mounted on the upper surface of the rack, an air cylinder is slidably arranged at the bottom of a cross beam of the gantry frame, a mounting plate is fixed to the telescopic end of the air cylinder, and a welding head is mounted on the lower surface of the mounting plate; and fixing cylinders are further included, the two fixing cylinders are fixed to the left side and the right side of the lower surface of the mounting plate, and moving plates are slidably connected to the opposite faces of the two supporting vertical plates. According to the device, a single honeycomb platform is automatically clamped through a motor and a wedge block, a guide plate is matched for abutting, an elastic floating roller is matched for pressing, positioning is stable, a workpiece is not damaged, full-area cleaning and negative-pressure synchronous impurity removal are adopted before welding, welding defects are effectively avoided, initial pre-stretching is conducted in the welding process, and the welding efficiency is improved. And then the progressive secondary stretching is realized along with the linkage of the welding machine head, the stress is dynamically eliminated, the deformation is inhibited, and the flatness and the welding precision are greatly improved.

The invention relates to the technical field of bogie suspension supports, and discloses an adjustable load-reducing and anti-falling support device suitable for a cantilever structure. The bracket body is arranged at the top of the auxiliary equipment; the connecting piece is arranged at the top of the bracket body; the adjustable elastic component is arranged on one side of the connecting piece; the pull ring is arranged at the bottom of the support body, and the pull ring is connected with the adjustable elastic component through a rigid pull rope; the fixed pulley assembly is arranged on one side of the support body and connected with the rigid pull rope. Vibration of the lower portion of the support body is restrained through the shock absorber, pre-stretching of the steel spring is achieved through the adjustable stud, failure of the steel spring is prevented through the adjusting bolt, and meanwhile the anti-disengaging function is achieved under the condition that the support body breaks down; therefore, the influence of auxiliary equipment on the long cantilever support and the large safety risk caused after the support is broken can be reduced.

The application provides a prestressed steel strand anchoring performance nondestructive detection method, and belongs to the technical field of steel strand performance detection, and comprises the following steps: applying a pre-tension force to a steel strand to be detected, unloading to zero after load preservation, so as to eliminate initial disturbance; applying a preset axial tensile load to the steel strand to be detected, the axial tensile load enabling the steel strand to be in an elastic stress state; under the condition of maintaining the axial tensile load, measuring a torsion angle generated by the steel strand within a gauge length; according to the torsion angle, determining a characteristic parameter representing a tensile-torsion coupling characteristic of the steel strand; comparing the characteristic parameter with a preset qualified judgment threshold value, and judging whether the anchoring performance of the steel strand to be detected is qualified based on a comparison result. The prestressed steel strand anchoring performance nondestructive detection method provided by the application realizes nondestructive detection and root-by-root screening of the steel strand.

The forward calculation method comprises the following steps: establishing a three-dimensional model of a lead screw transmission system and importing the three-dimensional model into a finite element analysis model to obtain a thermal deformation simulation model of a lead screw; taking the calorific value of each heat source and the heat exchange coefficient of each heat exchange surface as input conditions of a thermal deformation simulation model to obtain a thermal deformation result of the lead screw; calculating a front-end displacement change value of the front end of the lead screw in the axial direction of the lead screw based on the thermal deformation result of the lead screw, and calculating a rear-end displacement change value of the rear end of the lead screw in the axial direction of the lead screw based on the thermal deformation result of the lead screw; and according to the front-end displacement change value and the rear-end displacement change value of the lead screw, calculating the pre-stretching amount of the lead screw. According to the forward calculation method for the prestretching amount of the lead screw, the prestretching amount of the lead screw is calculated based on the non-uniformly distributed thermal deformation field of the lead screw, and the problem that the prestretching amount of the lead screw cannot be accurately calculated in the forward design stage of the initial stage of machine tool design is effectively solved.

The invention belongs to the technical field of numerical control machine tool equipment, and particularly relates to a lead screw pre-stretching mechanism for a numerical control machine tool. The device comprises a bearing seat, a lead screw and a tensioning nut used for pre-stretching the lead screw, one end of the lead screw is rotationally installed in the bearing seat through a pair of bearings, an installation hole used for installing the lead screw is formed in the bearing seat, an installation groove used for installing the bearings is formed in one side of the installation hole, and a spacer ring seat is connected into the installation groove; a bearing gland is fixedly mounted at one end of the bearing seat, and is matched with the spacer ring seat to seal the mounting groove; a supporting structure is installed in the installation hole and used for supporting the bearing, and the lead screw is in threaded connection with a locking nut used for pressing the supporting structure. According to the pre-stretching mechanism, the supporting structure is installed in the bearing seat to support the inner ring of the bearing, the problem that one side face of the inner ring of the bearing is damaged due to large axial force is avoided, the effect of protecting the bearing is achieved, and the overall structural strength of the pre-stretching mechanism is improved.

The invention belongs to the technical field of building steel beam welding, and particularly relates to a building steel beam structure positioning and welding system which comprises a welding platform and a conveying mechanism installed on the welding platform and used for conveying steel beams, and the conveying mechanism is provided with a fixing mechanism used for clamping and positioning the steel beams to be welded. A preheating mechanism used for heating a preheating zone formed by the steel beam to be welded is arranged in the conveying direction of the conveying mechanism. A preheating zone is precisely manufactured through the preheating mechanism, when weld metal is cooled and contracted after welding, the preheating zone is synchronously cooled and contracted, reverse traction force is generated and forms internal confrontation with the weld contraction effect, meanwhile, the pre-stretching effect before welding compensates part of contraction amount, welding residual deformation is greatly counteracted through cooperation of the two, and welding quality is improved. The geometric dimension deviation of the steel beam is controlled within an allowable range, secondary procedures such as flame correction and mechanical correction are avoided, the construction period is shortened, the construction cost is reduced, and damage of correction to base metal is avoided.

The application discloses a kind of fiber fabric reinforced cement-based composite material prestressed reinforcement system, including concrete structure, fiber fabric reinforced cement-based composite material layer, iron-based shape memory alloy material, monitoring control unit;The fiber fabric reinforced cement-based composite material layer includes fiber grid and inorganic cement matrix;The iron-based shape memory alloy material is arranged along the two ends of fiber grid extension direction in the fiber fabric reinforced cement-based composite material layer, one end is fixed with the fiber grid, the other end is fixed with the concrete structure;The monitoring control unit is connected with the fiber fabric reinforced cement-based composite material layer and iron-based shape memory alloy material.The application is arranged along the fiber direction by iron-based shape memory alloy material after pre-stretching, and pre-tightening force along the fiber direction is applied to fiber grid after being activated by heating, to prevent fiber bending in fiber layer, bending.

This invention discloses an installation method for a rubber waterstop at the intersection of an expansion joint and a construction joint, belonging to the field of building construction technology. It aims to solve the technical problem in existing technologies where, during installation at the intersection of an expansion joint and a construction joint, it is difficult to accurately control the initial stress state of the rubber waterstop in the direction of the expansion joint, leading to tearing or loosening and failure of the waterstop when the expansion joint expands or contracts. Key technical points include: determining the pre-tension amount δ based on the maximum possible expansion displacement Δ of the expansion joint, where δ = k·Δ, and k is a relaxation coefficient of 0.2 to 0.5; during installation, first fixing the bottom end of the waterstop, then applying tension to its top end using a tensioning device to achieve the pre-tension amount δ; then, for the waterstop, setting positioning bars to connect its flanges to the structural steel reinforcement; and finally, pouring concrete. This invention is mainly used for the installation of waterstops at the intersection of building expansion joints and horizontal construction joints, ensuring that the waterstop maintains a moderate tension within the joint.

The utility model is suitable for the technical field of connecting rods, and provides pre-stretching connecting rod bolt stretching detection equipment which comprises a top plate, a stretching assembly is installed at the bottom of the top plate, and the bottom of the stretching assembly is connected with a bottom plate; the stretching assembly comprises a stretching top plate, a plurality of sets of springs are arranged at the bottom of the stretching top plate, a stretching piece is arranged in the stretching top plate in a sleeved mode, and a pre-stretching module is arranged in the stretching piece in a sleeved mode; the pre-stretching module comprises a pre-stretching top plate, the bottom of the pre-stretching top plate is connected with two sets of pre-stretching hydraulic rods, and the output ends of the pre-stretching hydraulic rods are connected with pre-stretching bottom blocks. The device solves the problem that an actual stretching environment is difficult to simulate when the strength of a connecting rod bolt is detected, so that a dual stretching mode of the pre-stretching module and the main stretching module is adopted, and working condition changes in actual stretching assembly are effectively simulated through spring supporting and hydraulic rod control, so that the bolt is stressed more uniformly and deformed more controllably in the stretching process, and the strength of the bolt is detected. The detection precision is improved.

The application discloses an engineering vehicle side wall welding method and a tensioning tool, and relates to the field of railway engineering vehicle manufacturing.The welding method comprises the following steps: preparing the tensioning tool, the tool is provided with a rigid welding platform, and hydraulic tensioning units are symmetrically arranged at both ends of the platform; a plurality of skins are spliced on the platform, the skins are pulled tight and flat by the horizontal tension force of the hydraulic tensioning units, and the skins are fixed by points; the framework structure is welded on the tensioned skins, and the intermittent welding points are fixed and the plug welding is connected; the horizontal splicing weld is welded first, and then the longitudinal splicing weld is welded, and the segmented back-off welding method from the middle part to both ends is adopted; and the tension force is removed after complete cooling.The application forms a deformation control closed loop of "rigid platform reference support, multi-point and multi-dimensional controllable pre-tension, framework reinforced rigidity and optimal welding sequence", the tool and the process method are integrated and fused, welding internal stress and deformation can be effectively controlled, and the high-precision flatness manufacturing of the super-long thin plate structure part is realized.

The utility model discloses a lead screw pre-stretching structure for a numerical control machine tool, and relates to the technical field of lead screw mounting structures, the lead screw pre-stretching structure comprises a bearing seat main body, and one end of a lead screw can be mounted on the bearing seat main body; the bearing seat gland is mounted on the bearing seat main body, so that the screw rod is fixed; the bearing gland is arranged between the bearing seat main body and the bearing seat gland; the bushing is arranged on the screw rod in a sleeving manner; the locking nut is in threaded connection with the pre-stretching section of the lead screw; the first sealing assembly is arranged on the lead screw in a sleeving mode, and the first sealing assembly is connected between the bearing seat body and the bearing seat gland; and the second sealing assembly is arranged on the lead screw in a sleeving mode, and the second sealing assembly is connected between the bearing gland and the lining. The stretching effect is good, and the sealing performance is good.

The present invention discloses a repair process method for the inner lining of a thermal pipeline based on temperature strain compensation, which includes a thermal pipeline to be repaired, an external flange connector, a fixed sealing end cover, an inner lining repair pipeline, a pipe diameter reducer, a traction and stretching machine, a compressor, an air inlet hole, a connecting pipeline and an accessory valve. By pre-stretching the inner lining repair pipeline, the present invention can effectively eliminate the influence of the thermal stress on the inner lining pipeline at high temperatures; and an inner lining repair pipeline with an interference fit in pipe diameter size is adopted with the thermal pipeline, and through the method of inflating and expanding the pipe, the inner lining repair pipeline is closely attached to the thermal pipeline to be repaired, preventing the inner lining repair pipeline from shrinking and rebounding when there is no stretching effect.

This invention discloses an FKM skeleton-type sealing structure for a boiler ash remover, belonging to the field of sealing structure technology. It includes an FKM elastic sealing body, fixedly connected to the inner end face of the bearing cap of the boiler ash remover. The inner side of the sealing body has an inwardly wound sealing lip, forming an annular winding space. A self-tightening helical spring is embedded within the winding space, with the spring's free inner diameter smaller than the inner diameter of the winding space, and is in a pre-stretched state. The sealing lip is interference-fitted with the rotating shaft. The sealing body has a U-shaped cross-section, with circumferentially spaced anchoring grooves on its back. The inner wall and bottom surface of the U-shaped groove have circumferentially spaced anti-rotation protrusions for anti-torsion, enhanced pressure and extrusion resistance, and installation guidance. This invention replaces the original positioning ring, achieving self-positioning installation without auxiliary tooling, significantly extending the maintenance cycle, providing reliable sealing, and is suitable for boiler ash removal systems.

The utility model relates to the technical field of pipeline butt joint, and discloses a support for flue gas pipeline prestretching construction, which comprises two symmetrically arranged support rails, a rotating shaft is arranged between the two support rails, two support plates capable of being relatively adjusted are movably arranged on the rotating shaft, and the support rails are arranged on the support plates. Balls are movably arranged on the close end faces of the two supporting plates. Supporting rods are movably arranged at the ends, away from each other, of the two supporting plates, sliding rails are movably connected to the bottoms of the supporting rods, and the sliding rails are adjustably arranged in the supporting rails; according to the flue gas pipeline butt joint support, butt joint use of flue gas pipelines of various sizes can be met through adjustment of the supporting plate, and the height of one side of the support can be reduced through adjustment of the supporting plate so that convenience can be provided for moving out the pipelines from one side; and meanwhile, the resistance during pipeline butt joint movement can be greatly reduced through the arrangement of the balls, the construction convenience is improved, and the construction efficiency is improved.

The present invention discloses a pre-tension test tooling for steel cables on military aircraft, which relates to the technical field of aerospace. The present invention includes a horizontal plate and also includes a stretching and amplifying mechanism. The stretching and amplifying mechanism includes a positioning rod, the positioning rod is fixedly connected to the horizontal plate, the first support rod and the second support rod are sequentially rotatably connected to the circumferential side of the positioning rod, positioning grooves are provided on both the first support rod and the second support rod, a connecting frame is fixedly connected to the surface of the horizontal plate, a hydraulic cylinder is fixedly connected to the connecting frame, and a locking sleeve is fixedly connected to the output end of the hydraulic cylinder. When in use, the present invention magnifies the stretching condition of the steel cable through a cross-shaped scissors structure, so that it is convenient for the user to detect the length of the steel cable, and when the threshold value is reached, the limit of the locking rod on the control block can be released, so that when the fixed value is reached, the tension on the steel cable can be automatically released, avoiding excessive tension on the steel cable and preventing the steel cable from accidentally breaking when it is stretched too long.

The application discloses a manifold radiator based on regulation of internal structure morphology and a manufacturing method thereof, and belongs to the technical field of electronic cooling and thermal management. The manifold radiator is composed of a base, a packaging cover plate and a flexible partition plate. The internal flow channel of the base is divided into a central thermal flow channel and a side flow channel by the flexible partition plate. The uniform flow of a working medium is realized through a fluid equalization structure. The flexible partition plate is a composite plate composed of a spring steel belt and a NiTi thin belt. The flexible partition plate can change the width of the flow channel with temperature change, and realizes the on-demand distribution of the cooling working medium. During manufacturing, the base is processed by using oxygen-free copper. The spring steel belt is processed by gradient micro-ribs, and the NiTi thin belt is pre-stretched and trained before being compounded. The manifold radiator is manufactured through assembly, packaging and testing. The manifold radiator breaks through the limitation of traditional static structure, can adaptively adjust heat dissipation, and improves the anti-dry burning capacity.

The utility model discloses a casing pipe structure for preventing casing pipes from moving upwards during fracturing, which comprises a production casing pipe arranged in a stratum, the lower portion of the production casing pipe is fixed in the stratum through well cementation cement, the periphery of the upper portion of the production casing pipe is sleeved with a surface casing pipe, the axis of the surface casing pipe coincides with that of the production casing pipe, and the upper edge of the surface casing pipe is flush with the ground. The surface casing is fixed in a stratum through well cementation cement, the upper end of the production casing is upwards pre-stretched by a certain height, and an annular steel plate is welded and fixed between the surface casing and the production casing. According to the casing pipe structure, the underground stability and sealing performance of the casing pipe can be guaranteed, the problem that the free section of the casing pipe deforms in the fracturing process is solved, a better pressure bearing environment is provided for fracturing, potential safety hazards caused by the upward moving problem of the casing pipe to fracturing are solved, and the fracturing success rate is increased.