35results about How to "Reduce stress concentration points" patented technology

The invention discloses a flat membrane handpiece for producing PET tape yarn and belongs to the mechanical field of high polymer material machining. The flat membrane handpiece for producing the PET tape yarn is one of core devices of a tape yarn production line. The flat membrane handpiece comprises a yarn spraying hole and a flow channel and is characterized in that a flow retaining block is arranged in the flow channel. The yarn spraying hole is composed by meshing an upper die lip and a lower die lip. The upper die lip and the lower die lip are respectively provided with an adjustable bolt. The adjustable bolts and the flow retaining block are used for regulating flow of PET fondant. PET primary tape yarn with a rectangular cross section is directly extruded out of a meshed yarn spraying micro hole. The adjustable bolts extrude the lower die lip and adjust the size of the rectangular hole by means of elasticity of the lower die lip so as to achieve the aim of controlling the thickness of the PET tape yarn. The tape yarn is formed after cooling and traction forming techniques. The flat membrane handpiece for producing the PET tape yarn can effectively solve the problem that yarn is prone to fracture in the process of traction and weaving, dies are reasonable in structural design and industrial production can be met.

The invention relates to the field of the modified polystyrene, and provides a high impact-resistance anti-smoldering polystyrene resin composite and a preparation method thereof. The composite comprises the following components: 70 to 85 parts of polystyrene, 8 to 15 parts of fire retardant, 3 to 4.5 parts of auxiliary fire retardant, 0.2 to 1.5 parts of stabilizer, 0.2 to 1.0 part of lubricant,0 to 0.5 part of dispersion oil and 0.2 percent of other assist agents. The high impact-resistance anti-smoldering polystyrene resin composite is prepared by selecting the high impact-resistance polystyrene, fire retardant and other assist agents and by improving the compatibility of the fire retardant and the basal material high impact-resistance polystyrene (HIPS). The composite has high fire retardance, no smoldering and good impact resistance, and is particularly suitable for producing the products requiring high retardance such as electronic elements, parts, shell materials of electronicdevice, and the like.

The invention discloses a mesophase pitch-based graphite fiber/polypropylene composite material and a preparation method thereof. The mesophase pitch-based graphite fiber/polypropylene composite material is prepared from the following components in parts by weight: 55-75 parts of polypropylene, 2-6 parts of mesophase pitch-based graphite fiber, 5-10 parts of boron nitride, 0.5 part of a coupling agent, 4 parts of maleic anhydride-grafted polypropylene, 5-7 parts of a compatilizer, 5-8 parts of nano-magnesium hydroxide, 2-6 parts of a flexibilizer and 2 parts of other assistants. Polypropylene is modified through selecting the mesophase pitch-based graphite fiber and compounded with the related flexibilizer, coupling agent, compatilizer, fire retardant and lubricant, and the mesophase pitch-based graphite fiber/polypropylene composite material is prepared through a blending mode, so that the heat-conducting property and the flame retardant property are very excellent, a heat-conducting filler and matrix resin are good in compatibility and good in mechanical properties, and furthermore, the machining process is relatively simple.

The invention discloses a dry air-sealed end face groove profile rotating bilaterally. The dry air-sealed end face groove profile is provided with a movable ring end face, wherein 8-12 dynamic pressure grooves are uniformly distributed on the dynamic ring end face along a circumferential direction; each dynamic pressure groove is concave; the depth of each dynamic pressure groove is 5-15 mum; and each dynamic pressure groove has a concave structure constructed by an inlet arc line which is formed on the outer circumference of a dynamic ring, a left outer-side arc edge and a right outer-side arc edge which are connected to the two ends of the inlet arc line symmetrically, a left outer side straight edge and a right outer side straight edge which are correspondingly connected to the other ends of the left outer side arc edge and the right outer side arc edge respectively and of which the extension lines are vertical to the inner circumference of the dynamic ring, a left groove root and a right groove root which are correspondingly connected to the other ends of the left outer side straight edge and the right outer side straight edge respectively and are parallel to the outer circumference of the dynamic ring and the inner circumference of the dynamic ring, and a middle isolating block of which the periphery is connected with the other ends of the left groove root and the right groove root. Due to the adoption of the dry air-sealed end face groove profile, the sealing pneumatic performance can be improved, the groove profile processing difficulty is lowered, the matching property of a sealed groove profile and the practical requirement is improved, and the higher requirement of modern industry on sealing is met.

The invention discloses assembly process of tower sections for a large-diameter wind-power tower tube. The two tower sections are placed on corresponding groups of roller racks. Two groups of support rollers are arranged on each group of roller racks with one roller being as a main driving roller. Three groups of alligator-type assembly machines having rollers are positioned according to different positions in the tower sections by pushing the three groups in the tower sections. Main driving rollers of the groups of roller racks drive the two tower sections to rotate at the same time. During rotation of the tower sections, CO2 gas is utilized for shielded welding, positioning and welding in the position within the range of 200-300 mm of liftable roller centers of the three groups of alligator-type assembly machines having rollers. Positioning and welding are carried out in three positions at the same time. The assembly process of the tower sections for the large-diameter wind-power tower tube has following beneficial effects: continuous adjustments are made to overall alignment tolerance of whole sections of circular arcs in order to reduce stress concentration points at butt joints; stress can be uniformly distributed and quality risk is reduced; assembly efficiency is greatly improved; and accuracy quality is ensured.

The invention discloses a lug plate structure with equal and colinear stress, and an engineering machine, belonging to the field of machine manufacturing. The lug plate structure comprises a box structure and a lug plate assembly, wherein the box structure comprises a top plate 10 with a bent end, and a bent rear bent plate 8, the bent end of the top plate 10 is connected with the rear bent plate 8, the lug plate assembly comprises two upper lug plates 5 arranged on the top plate 10 of the box structure, one end of each upper lug plate 5 is connected with the top plate 10 and is adjacent to the bent end of the top plate 10, and the tangential direction of the other end of each upper lug plate 5 is the same as that of the bent end of the top plate 10. According to the technical scheme, the lug plate structure with a colinear design is adopted, and the tangential direction of each lug plate is the same as that of the top plate, so the overall stress is homogenized, the stress on the bent plate and a butt welding seam is reduced, and the service life is prolonged.

The invention discloses a sleeve type osteotomy segment diaphysis prosthesis, and belongs to the field of medical equipment. The sleeve type osteotomy segment diaohysis prosthesis comprises a first prosthesis, a second prosthesis and a patch. The first prosthesis comprises an intramedullary stalk a and a connecting block. The lower end of the intramedullary stalk a is fixedly connected with the upper end of the connecting block, the lower end of the connecting block is provided with a blind hole, and the diameter of the connecting block is greater than the diameter of the intramedullary stalk a. The second prosthesis comprises an intramedullary stalk b and a plug matched with the blind hole, the upper end of the intramedullary stalk b is fixedly connected with the lower end of the plug, the side wall of the connecting block is provided with a gap matched with the patch, the gap is communicated with the lower end of the connecting block and the blind hole, the patch is a trapezoid, and the area of the back face of the trapezoid is greater than the area of the front face. By the adoption of the connecting block, no thread fixation is needed, and the service life is prolonged; the design of the gap and the patch can reduce a pull-apart distance between two diaphysis, the difficulty of operation is reduced, and at the same time, the fixation strength is increased.

The invention relates to the technical field of steel pipe processing equipment, in particular to a processing device for shearing welded steel pipes. The processing device comprises a base, upright posts are symmetrically and fixedly connected to the surface of the base, a cross beam is fixedly connected to the end parts of the upright posts, and an air cylinder is fixedly connected to the bottomsurface of the cross beam and is connected with a connecting piece; and the connecting piece is fixedly connected with a protective cover, and the protective cover is rotatably connected with a knifeflywheel. The processing device solves the problems that according to an existing shearing machining device for welded steel pipes, the clamping effect is not ideal, a clamp is prone to breakage, theproduction efficiency of companies is seriously affected, and the production cost is greatly improved, and the processing device is reasonable in structural design, and convenient to use, improves the clamping effect, reduces impact on the clamp, eliminates stress concentration points of the device, avoids clamp breakage, improves the working efficiency, reduces the production cost and improves the economic benefits of enterprises when used for shearing the welded steel pipes.

The invention relates to the technical field of rubber product forming, in particular to a self-adaptive base blank forming machine and method. The self-adaptive base blank forming machine comprises amachine base, a die and a rack, wherein the machine base comprises a base body and a rotatable platform mounted on the base body, and the die is mounted on the rotatable platform, so that the die canrotate along with the rotatable platform; the rack comprises pressing rollers, and the pressing rollers are used for acting on a material layer laid on the die. The self-adaptive base blank forming machine and method are provided in order to solve the problem that a stress concentration point can be formed at a lap joint between two cord fabric layers in an arc-shaped area of a self-adaptive rubber base due to adoption of an existing self-adaptive rubber base forming process.

The invention discloses a fresh-keeping film containing aerogel and a preparation method thereof. The prepared fresh-keeping film has relatively high tensile strength and relatively good mechanical properties; meanwhile, the moisture permeability and the light transmittance are relatively high; the inhibition rate of colletotrichum gloeosporioides for causing a mango anthracnose disease reaches about 96 percent and the bacterium-inhibition effect is remarkable. According to the fresh-keeping film, nano-silver is treated by utilizing acetic acid, and the dispersity of the nano-silver in tetraethyl orthosilicate is improved, so that a stress concentration point is reduced and the mechanical properties of the fresh-keeping film are improved; one layer of the aerogel is formed on the surface of the nano-silver by utilizing tetraethyl orthosilicate, so that the moisture permeability of the fresh-keeping film is improved; an aerogel layer and the nano-silver have a cooperative effect to realize the effects of adsorbing and inhibiting the colletotrichum gloeosporioides, and the bacterium-inhibition rate is improved; neopentyl glycol is used for further treating silicon dioxide aerogel modified nano-silver and a crosslinking point can be formed by compound particles; the crosslinking point and a polyvinyl alcohol substrate can be subjected to crosslinking reaction to form a uniform crosslinking network, so that the mechanical properties of the fresh-keeping film are greatly improved.