147 results about "Maximum diameter" patented technology

The invention discloses a steel pipe diameter and out-of-roundness measuring method based on ellipse fitting. The method comprises the following steps: acquiring section contour data of a steel pipe; utilizing an improved ellipse fitting algorithm to obtain an optimal ellipse model and a corresponding local point; reconstructing steel pipe section contour measurement data through a linear interpolation algorithm; and the maximum diameter and the minimum diameter of the steel pipe are calculated by using the reconstructed steel pipe section contour measurement data, so that the out-of-roundness of the steel pipe is determined. On the basis of geometric distribution of data points and high efficiency of an improved ellipse fitting algorithm, steel pipe section contour measurement data can be accurately reconstructed; according to the improved ellipse fitting algorithm, the confocal hyperbolic distance is used for replacing the algebraic distance, the actual geometric distance from the steel pipe section contour data points to the fitting ellipse can be accurately reflected, the fitting ellipse better conforms to the actual section contour of the steel pipe, effective data points are obtained, and the fitting precision is improved. Noise points and outliers generated by a measuring instrument and the environment are eliminated, and the measuring precision is improved.

The present invention discloses a floating trough structure for winding a buffer paper pad and a buffer paper pad winding device. The floating trough structure includes a trough, a rotating shaft, a limiting plate, a driving mechanism, and a reset component. The trough can swing from a horizontal state to a non-horizontal state. The driving mechanism can drive the limiting plate to swing with the rotating shaft as the swing center. The reset component can drive the trough to maintain a tendency to swing from a non-horizontal state to a horizontal state. The buffer paper pad winding device includes a winding mechanism and a floating trough structure. With the floating trough structure of the present invention, regardless of whether the buffer paper pad roll wound by the buffer paper pad winding device has the minimum diameter or the maximum diameter, the trough is tightly attached to the outer periphery of the buffer paper pad roll, and the tightness can be guaranteed. The diameter of the buffer paper pad roll wound by the buffer paper pad winding device can be changed between the minimum diameter and the maximum diameter, and it can ensure that the adhesive tape is firmly adhered and wound around the outer periphery of the buffer paper pad roll to prevent the buffer paper pad roll from unraveling.

The utility model relates to a precast pile which comprises a bottom pile body and a connecting pile body. The bottom pile comprises a first pile body, a pile tip and a first pile splicing connector, and the pile tip and the first pile splicing connector are located at the two ends of the first pile body in the axial direction correspondingly. The connecting pile comprises a second pile body and second pile splicing connectors, the second pile splicing connectors are located at the two ends of the second pile body in the axial direction, and the second pile splicing connector at one end of the connecting pile is connected with the first pile splicing connector of the bottom pile; the first pile body and the second pile body comprise a plurality of pile bodies, each pile body is provided with a first pile section and a second pile section, the direction from the connecting pile to the bottom pile is defined as the first direction, the diameter of the first pile section is linearly increased in the first direction, the diameter of the second pile section is linearly decreased in the first direction, and the maximum diameter of the first pile section is equal to the maximum diameter of the second pile section. The precast pile can effectively improve the friction force between the pile wall and soil around the pile, and the single-pile bearing capacity of a friction pile is improved.

An asymmetric self-aligning roller bearing for a fan and its design method. The asymmetric self-aligning roller bearing is composed of an outer ring, an inner ring, a row of spherical rollers A, a row of spherical rollers B, and a cage. The bearing has different contact angles. The outer ring raceway is a spherical arc with a continuous radius value R, and the center of the sphere O is at the demarcation point of the widths B1 and B2 on the bearing center line. The long spherical rollers and the short spherical rollers have the same maximum diameter and spherical radius value, but different lengths. At the same time, this solution also discloses the design method of the bearing of the present invention. The bearing with different contact angles described in the present invention is applicable to the working conditions of a wind power main shaft, has a large axial load-bearing capacity, and the same diameter and spherical radius value of the double-row rollers make the manufacturing cost lower.

The invention discloses a floating trough structure for buffering paper pad rolling and a buffering paper pad rolling device.The floating trough structure comprises a trough, a rotating shaft, a limiting plate, a driving mechanism and a reset component, the trough can swing from a horizontal state to a non-horizontal state, and the driving mechanism can drive the limiting plate to swing with the rotating shaft as the swing center; the reset component can drive the material groove to keep a trend of swinging from a non-horizontal state to a horizontal state, and the buffering paper pad winding device comprises a winding mechanism and a floating material groove structure. According to the floating trough structure, no matter whether a buffer paper pad roll wound by the buffer paper pad winding device has the minimum diameter or the maximum diameter, the trough is tightly attached to the periphery of the buffer paper pad roll, the tightness can be guaranteed, the diameter of the buffer paper pad roll wound by the buffer paper pad winding device can be changed between the minimum diameter and the maximum diameter, and the buffer paper pad roll wound by the buffer paper pad winding device is not prone to falling off. And the adhesive tape can be firmly adhered and wound on the periphery of the buffer paper pad roll, so that the buffer paper pad roll is prevented from being scattered.

A rolling mill includes three or more rolling rolls aligned along a circumferential direction and arranged so each rotary shaft is skewed with respect to a pass line of a material to be rolled, wherein the material to be rolled made of a pipe or bar material passes between the rolling rolls while being rotated to undergo diameter reducing rolling. At least one rolling roll selected from the three or more rolling rolls is smaller in roll diameter than at least one other rolling roll. When at least one rolling roll having a relatively maximum roll diameter defined as a maximum diameter rolling roll and at least one rolling roll smaller in roll diameter than the maximum is defined as a small diameter rolling roll, the small diameter rolling roll has a roll diameter equal to or less than 90% of the roll diameter of the maximum diameter rolling roll.

The invention provides a hole flanging and in-mold tapping process for a high-strength plate, and relates to the technical field of automobile part machining. The hole flanging and in-die tapping process for the high-strength plate comprises the steps that firstly, a convex hull is punched and drawn, a female die is of a through hole structure, the hole diameter is 0.1 mm smaller than the target outer diameter of a flanged hole on one side, the top of a punch is designed to be an inverted-cone smooth arc-shaped protrusion, the diameter of the protrusion is 0.25 mm larger than the maximum diameter of a chamfer of an inner hole of the flanged hole on one side, the curvature radius R of the arc is 0.5-1 mm, and the height of the convex hull is accurately controlled to be 30% + / -0.05 mm of the thickness of a material; it is ensured that the plastic flow allowance of 30% of the material thickness exists in the follow-up pressure returning procedure; secondly, convex hull forming is conducted, and a 90-degree + / -1-degree inverted-cone-shaped knot is adopted as a punch. Materials needed by hole flanging are drawn into a convex hull through convex hull punching and drawing, the shape of a flanged hole is formed through back upsetting, meanwhile, burrs are reversely patted after punching is conducted, broken burrs generated after punching are extruded to be smooth again, and it is guaranteed that in the subsequent hole flanging procedure, the end face of the flanged hole cannot have serious cracks and sawtooth shapes.

This application discloses an insulated torsion bar spline, comprising a straight section, a recessed section, a tapered section, and a bottom section arranged sequentially from top to bottom. The maximum diameter of the recessed section, tapered section, and bottom section is less than or equal to the diameter of the straight section. The total height of the insulated torsion bar spline is defined as L, the height of the straight section as L1, the height of the recessed section as L2, the height of the tapered section as L3, and the height of the bottom section as L4, satisfying the following conditions: 10%L≤L1≤15%L, 38%L≤L2≤43%L, 45%L≤L3≤49%L, and L4≤1%L. The diameter of the straight section is defined as D, and the maximum depth of the recessed section is 2%~4%D. The insulated torsion bar spline is made of metal, and the straight section, recessed section, tapered section, and bottom section are connected as a single structure. This application's insulated torsion bar spline, through optimization of its shape and dimensions, effectively improves the torque of the insulated torsion bar.

This invention discloses a method, apparatus, equipment, and storage medium for detecting annular flow pressure drop in wellbore. The method includes: fitting acquired electrical logging data of the well diameter of the target well; processing an irregularly enlarged well section into a concave arc-shaped wellbore to be tested; obtaining the maximum diameter and concave height of the concave arc-shaped wellbore; determining the diameter enlargement factor of the concave arc-shaped wellbore based on the maximum diameter and the pre-acquired drill bit diameter of the target well; and inputting the diameter enlargement factor, the concave height, and the drilling data of the target well into a pre-constructed model of an irregular wellbore annular flow pressure drop in a reference well for calculation to obtain the annular flow pressure drop of the target well. This method enables rapid detection of the annular flow pressure drop of the target well based on the annular flow pressure drop of the reference well, improving the detection efficiency of annular flow pressure drop in irregular wellbore annulus.

This utility model discloses a floating material trough structure and a buffer paper pad winding device for winding buffer paper pads. The floating material trough structure includes a material trough, a rotating shaft, a limiting plate, a driving mechanism, and a resetting component. The end of the material trough is provided with a flange, allowing the material trough to swing from a horizontal state to a non-horizontal state. The driving mechanism drives the limiting plate to swing around the rotating shaft as the swing center. The resetting component ensures that the material trough maintains a tendency to swing from a non-horizontal state to a horizontal state. The buffer paper pad winding device includes a winding mechanism and the floating material trough structure. With this utility model's floating material trough structure, regardless of whether the wound buffer paper pad roll has the minimum or maximum diameter, the material trough remains tightly attached to the outer periphery of the buffer paper pad roll, ensuring adequate tightness. The diameter of the buffer paper pad roll wound by the buffer paper pad winding device can vary between the minimum and maximum diameters, and it ensures that the tape is firmly adhered and wrapped around the outer periphery of the buffer paper pad roll, preventing the buffer paper pad roll from unraveling.

A connecting structure of one embodiment includes: a first bus bar having a first through-hole; a second bus bar having a second through-hole; a connecting member having an axis, a first overhanging portion, and a second overhanging portion; and an elastic member through which the axis penetrates. The first through-hole is defined by a first circumferential surface having a cross-sectional shape along a circumference of a virtual circle and extending from a first facing surface to a first pressed surface, and a first recessed surface; the second through-hole is defined by a second circumferential surface and a second recessed surface.the elastic member has an outer peripheral diameter larger than the circumference of the virtual circle and an inner peripheral diameter smaller than a maximum diameter of the first overhanging portion; the second overhanging portion is insertable into the first through-hole and the second through-hole while fitting into a recess defined by the first recessed surface and the second recessed surface at a first rotational position; and the second overhanging portion overlaps a second pressed surface, when viewed in a penetration direction, at a second rotational position.

The invention provides a conical barrel clamping piece anchorage device for mechanical connection of building components, which comprises a conical barrel, a sleeve, clamping piece anchors, a component at one end and a component at the other end, two sets of clamping piece anchorage devices are respectively sleeved on the component at one end and the component at the other end, and the conical barrel is integrally formed and comprises an equal-diameter section and a variable-diameter section; the tail end of the equal-diameter section is fixedly connected with the maximum-diameter end of the variable-diameter section, the head end of the equal-diameter section is provided with internal threads, the two ends of the sleeve are provided with external threads, and the two conical barrels penetrate through a component at one end and a component at the other end respectively. The variable-diameter sections are arranged on the clamping piece anchorage devices arranged at the connecting end of the component at one end and the connecting end of the component at the other end in a sleeving mode respectively, and the minimum diameter of the variable-diameter sections of the conical cylinder is matched with the sum of the diameter of the building component and the thickness of the clamping piece anchorage devices. The invention further discloses a method for connecting building components through the cone clamping piece anchorage device type connecting device. The method has the advantages of simple structure, simplicity and convenience in construction, shortened construction period and wide application range.

A polyester-resin-coated seamless can including a reduced diameter portion obtained by neck processing within a distance of 0% to 15% from a can body uppermost portion with respect to a total height of the can from the can body uppermost portion to a can bottom of the can. A ratio Im / Iu is 1.0 or more, where Iu (cps / μm) is calculated by dividing a maximum peak intensity in a range satisfying 15°≤2Θ≤19° of an outer-surface coating in a maximum reduced diameter portion of the reduced diameter portion by a thickness of the coating at the measurement site, and Im (cps / μm) is calculated by dividing a maximum peak intensity in a range satisfying 15°≤2Θ≤19° of outer-surface coating at a measurement site within a distance of 45% to 60% from the can body uppermost portion by a thickness of the outer-surface coating at the measurement site.

To prevent a sealant from entering a space when there is a space between a first circuit member and a second circuit member.SOLUTION: A thermosetting sealing sheet 4P is used to seal a mounting structure 10 including a first circuit member 1 and a plurality of second circuit members 2 mounted on the first circuit member, having at least a first layer 41P, the first layer is composed of a first thermosetting resin composition, the first thermosetting resin composition includes a first filler, the first filler includes non-spherical particles, a gap is present between the first circuit member and the second circuit member, and an average distance L between the first circuit member and the second circuit member and an average value Dma of maximum diameters Dm of the non-spherical particles satisfy Dma / L≥0.1.SELECTED DRAWING: Figure 4

The application provides an outer wall protection device for a socket metal pipe, the outer wall protection device is a ring segment with the same center as the socket metal pipe to be protected, a hollow cylinder is formed by more than two ring segments, the socket metal pipe is sleeved in the hollow cylinder, the outer diameter of the hollow cylinder is greater than or equal to the outer diameter of the pushing flange and smaller than the maximum diameter of the socket segment sleeved in the hollow cylinder; the outer wall protection device comprises a first ring segment and a third ring segment; the first ring segment is adjacent to the reinforcing support during installation, and the third ring segment is matched with the socket segment. The application eliminates the longest curing process in the production of nodular cast iron pipes, shortens the pouring link in the preparation process of the nodular cast iron pipes, forms the required structure of the outer wall and the socket metal pipe in stages, and thus improves the production efficiency of the metal pipe.

To provide a container that can restrict movement of stored articles during transportation and can prevent damage to the container and the articles as much as possible.SOLUTION: A container 1 includes a bottom wall 2 and a side wall 3, and is box-shaped and open upward. The bottom wall 2 includes: a flat, non-porous general portion 31; and a large protrusion 32 and a small protrusion 33 provided in the entire upper surface of the general portion 31. The large protrusion 32 has a height from the general portion 31 to an apex and the maximum diameter in a planar view larger than the small protrusion 33. Each of the protrusions 32 and 33 has a generally circular shape in a planar view and a curved cross-section, with the large protrusion 32 and the small protrusion 33 arranged alternately. The rounded shape of each of the protrusions 32 and 33 minimizes damage to the articles stored in the container 1 and the protrusions during transportation. Furthermore, the articles are supported not only by the large protrusion 32 but also by the small protrusion 33, effectively restricting their movement.SELECTED DRAWING: Figure 1

The invention provides a grinding method for a roller and a grinding machine, and relates to the technical field of machining. The grinding method for the roller comprises the following steps that a groove is formed in the roller face of the end of the roller to be machined, and a first roller is obtained; acquiring a surface profile curve of the first roller; based on grinding treatment parameters, grinding treatment is conducted on the first roller, and a second roller is obtained; wherein the grinding treatment parameters comprise grinding current, and the grinding current is used for representing the maximum limiting current determined on the basis of the surface profile curve. The grooves are formed in the roller surface of the end of the roller, the maximum diameter change value of the surface of the roller is increased, the surface profile curve of the roller is made to change, then the grinding machine control system improves the maximum limiting current set value, traditional grinding current limitation is broken through, the grinding process can be stably operated under the higher current condition, and the grinding efficiency is improved. The material removal efficiency is improved; and the processing time is shortened.

The present invention relates to a drill bit and a method of manufacturing a perforated article. In the case where the rigidity of the main shaft of a perforating machine is sufficient, it goes without saying, but even in the case where perforation is performed using a hand-held tool rotation device or the rigidity of the main shaft of the perforating machine is low, a workpiece composed of a composite material or a metal or the like can be perforated with high accuracy. The drill bit of the embodiment has a first cutting edge formed on the leading end side in such a manner that the leading end angle is continuously or discontinuously reduced from the leading end side to the trailing end side, and on the other hand, the clearance angle is continuously or discontinuously reduced from the leading end side to the trailing end side, and is used to perforate a workpiece to form a pilot hole; a second cutting edge formed by being positioned away from the first cutting edge toward the trailing end side, and used to perform finishing of the pilot hole, and having a clearance angle at the maximum diameter position; and a vibration-damping portion formed between the first cutting edge and the second cutting edge, and reducing vibration of the second cutting edge by being inserted into the pilot hole processed by the first cutting edge.

To provide a ball bearing which can optimize the diameters of a plurality of balls with different sizes as a roller and which can contribute to reduction in rotation torque and increase in acceptable load.SOLUTION: A representative configuration of a ball bearing 100 includes: an outer ring 110; an inner ring 120; and a plurality of balls that roll between the outer ring and the inner ring. As the balls, balls with different diameters are regularly aligned. When a parameter γ representing an internal configuration of the bearing is indicated by the following formula: γ=(Da / PCD)*cosα (where Da is the diameter of the ball, PCD is a pitch circle diameter, and α is a contact angle), a maximum ball diameter difference ΔDa between a ball with the largest diameter (largest-diameter ball 132) and a ball with the smallest diameter (smallest-diameter ball 134) is within a range of (7.52×10-4γ+8.91×10-4)*Da≤ΔDa≤(6.43×10-3γ+7.62×10-3)*Da when γ≤0.09, and (-9.65×10-4γ+1.05×10-3)*Da≤ΔDa≤(-8.25×10-3γ+8.98×10-3)*Da when γ>0.09.SELECTED DRAWING: Figure 2

The invention discloses a design method of a spinning sectioning mandrel for a thin-wall curved generatrix piece with a spiral inner rib. In the core mold for spinning the part with the spiral inner rib, a split core mold is arranged on the outer circumferential surface of a main core mold in a sleeving manner, and the end face of the tail end of the split core mold is attached to the surface of a base of the main core mold; the clamping block is sleeved on the outer circumferential surface of the tail end of the split core mold; and the main core mold and the split core molds are connected together by bolts through round holes in the end surfaces of the heads of the split core molds. The split core mold is formed by combining m active core mold petals and n passive core mold petals. The outer diameter of the split core mold is the same as the maximum diameter of the inner surface of a workpiece; axial key grooves are formed in the inner surfaces of the driving core mold petals and the driven core mold petals; and the inner surface of the split core mold is in clearance fit with the outer surface of the main core mold. According to the spinning forming method, smooth spinning forming of the thin-wall curved generatrix piece with the spiral inner rib is guaranteed, the production period is shortened, the production efficiency is improved, the production cost is reduced, the labor intensity is reduced, and the forming quality and the forming precision of the workpiece are improved.

Aspects of the disclosure relate to a package, a carrier (90) for packaging one or more articles (B, B1, B2) and a blank (10; 110; 210; 310A, 310B) for forming the carrier. The package comprises an article carrier and one or more articles. The carrier comprises a main panel (14) having at least two article retention structures for receiving and securing the main panel to a respective article. Each of the at least two article retention structures comprises a center. The center C of the at least two article retention structures is spaced apart from the center of an adjacent one of the at least two article retention structures by a distance. The distance is greater than the maximum diameter of each of the at least two articles.

The high-sensitivity and large-stroke air spring mechanism comprises an air spring body and a pressure storage bin, the air spring body comprises an elastic telescopic part and a sealing plate, the elastic telescopic part comprises a plurality of telescopic units connected in sequence, each telescopic unit comprises a disc-shaped sleeve and an annular edge plate, and the disc-shaped sleeve is connected with the sealing plate. The middle of the side wall of the dish-shaped sleeve is concaved inwards to form a V shape, an inner hole in the middle of the dish-shaped sleeve comprises conical hole sections located on the two end sides and a middle hole section, the dish-shaped sleeve can stretch and deform when subjected to axial force, when the dish-shaped sleeve is in a natural state, the diameter of the maximum diameter position of each conical hole section is D2, the diameter of each middle hole section is D1, and D1 / D2 is smaller than or equal to 1 / 4. Annular edge plates are fixedly arranged at the two ends of the dish-shaped sleeve correspondingly, the annular edge plates of every two adjacent telescopic units are fixedly connected, and sealing plates are connected to the two end sides of the elastic telescopic part correspondingly. And the pressure storage bin is communicated with a spring air cavity in the air spring body through a pipeline.

The utility model relates to a novel blank punching tool which comprises a die body, a forming cavity and a limiting cavity which sequentially extend in the vertical direction are formed in the middle of the die body, and the forming cavity is communicated with the limiting cavity. The base assembly comprises a leakage plate pad and an insert, the leakage plate pad is embedded in the limiting cavity, a first through hole extending in the vertical direction is formed in the middle of the leakage plate pad, a limiting part is formed in the position, located at the top end of the first through hole, of the leakage plate pad, the insert abuts against the limiting part, and a second through hole extending in the vertical direction is formed in the middle of the insert; the maximum diameter of the second through hole is smaller than or equal to the minimum diameter of the first through hole; and the outer peripheral surface of the punch assembly can be connected with the hole wall of the second through hole in a sliding manner. The utility model provides a novel blank punching tool with high efficiency and high yield through the die body, the drain plate, the insert and the punch assembly, and the novel blank punching tool has the advantages of good interchangeability, reduction of the cost of forgings and guarantee of the product quality.

This invention proposes a mold steel with uniformly distributed inclusions and a low deformation rate, and its manufacturing method. The steel plate composition, by weight percentage, is as follows: C: 0.45%–0.55%, Si: 0.20%–0.30%, Mn: 0.20%–0.40%, P≤0.015%, S≤0.015%, Cr: 3.0%–4.0%, Mo: 3.0%–3.5%, V: 0.70%–0.80%, Ni: 0.80%–0.90%, Sc: 0.02%–0.03%, Zn: 0.03%–0.05%, wherein Ni / V = 1.125–1.145, Sc+Zn = 0.06%–0.07%, and the balance is Fe and unavoidable impurities. The steel plate production method includes smelting, continuous casting, slab heating, rolling, straightening, slow cooling, normalizing + annealing pretreatment, and quenching and tempering. The number of inclusions per unit area in the microstructure of the mold steel of this invention is (192-205) inclusions / mm. 2 The average particle size is 1.75μm to 1.85μm, fine and uniformly dispersed. The ratio of the maximum diameter to the minimum diameter of the inclusions is 1.69 to 1.78, approximately spherical. The thickness of the mold steel of this invention is 30 to 180 mm; the hardness of the steel plate is 46 to 48 HRC, and the hardness difference between the thickness and the cross-section is ≤2 HRC; the unnotched room temperature transverse impact toughness of the core is 220 to 230 J; the wear volume at 800℃ is (25 to 26) × 10⁻¹⁰. ‑3 mm 3 It has high thermal conductivity at high temperatures, with a thermal conductivity of (35~36) W·m at 800℃. ‑1 ·K ‑1 .

A composition for making a core for use in a moulding or casting process, a core comprising said composition, and a mould for producing an article by high pressure die casting or semi-solid casting. The composition comprises a particulate refractory material, a binder composition comprising at least one hydrophilic polymer, comprising at least one polysaccharide or polysaccharide derivative; and at least one pozzolanic additive. The mould comprises a core for defining an internal cavity of the article and the core comprises a solidified core composition. The solidified core composition comprises a particulate refractory material and a binder composition, degrades in water such that a cylinder of the solidified core composition having a maximum height of 80 mm and a maximum diameter of 50 mm disintegrates in no more than 10 minutes when immersed in water at a temperature of 20° C. and stirred at a speed of 60 rpm, and has a flexural strength of at least 300 N / cm2. The invention also resides in a method for producing an article by high pressure die casting or semi-solid casting.

A cylindrical side-wall core is acquired from an inner circumferential surface of a well at a predetermined depth from a ground surface. First, second and third measurement cross sections spaced apart in a longitudinal direction of the core are set. In each cross section, the length of the maximum diameter of the cross section where the amount of distortion relative to the diameter of a standard circle is largest and the length of the minimum diameter where the amount of distortion relative to the diameter of the standard circle is smallest are measured. Six independent components among stress tensors for defining three-dimensional stress elements are obtained using an equation representing a difference between maximum and minimum stresses acting on the side-wall core along each cross section and another equation representing the angle between the well excavation direction and the action direction of the maximum stress on each cross section.

The extrusion equipment for SPC floor production comprises a machine barrel, a pair of conical screws with opposite rotating directions, a driving device in transmission connection with the pair of conical screws and a confluence core installed at a discharging port of the machine barrel, and each conical screw comprises a conical rod body extending from front to back and a thread spirally extending around the conical rod body; the bottom diameter of the conical rod body is gradually reduced from front to back, the outer diameter of the threads is gradually reduced from front to back, the maximum diameter of the conical screw rod is 200-250 mm, and the minimum diameter of the conical screw rod is 100-150 mm; the conical rod body is sequentially provided with a feeding section, a first mixing section, a second mixing section, a first metering section, an exhaust section and a second metering section from front to back, the threads are double-end threads on the feeding section, the first mixing section and the second mixing section, the threads are single-end threads on the first metering section, the threads are four-end threads on the exhaust section, and the threads are three-end threads on the second metering section; the extrusion device can efficiently and stably extrude materials in a low-consumption and high-quality mode, and is particularly suitable for production of SPC plates.

The invention belongs to the field of abrasive grinding tools, and particularly relates to a wafer thinning grinding wheel and a preparation method thereof.The wafer thinning grinding wheel comprises a base plate 1, an abrasive coating 11 is fixed to the end face of the base plate 1, abrasive particles are arranged in the abrasive coating 11, and the abrasive particles comprise first abrasive particles 12 located at the bottom of the abrasive coating 11 and close to the end face of the base plate 1; the abrasive material further comprises second abrasive particles 13 arranged in a layer above the first abrasive particles 12, the average diameter of the first abrasive particles 12 is 110%-140% of the diameter of the second abrasive particles 13, and the minimum diameter of the first abrasive particles 12 is not lower than 70% of the maximum diameter.

The utility model discloses a special-shaped drill bit, which relates to the technical field of construction drilling equipment, can be arranged in a pile casing in a penetrating manner, and structurally comprises a sleeve, one end of the sleeve is used for being connected with a drill rod, and the other end of the sleeve is provided with a slag outlet; the special-shaped protective ring is fixedly arranged on the outer side of the sleeve in a sleeving mode, one side of the special-shaped protective ring is of an inwards-concave structure, and the maximum diameter of the special-shaped protective ring is smaller than the inner diameter of the protective cylinder. And the conical cutting edge is obliquely connected between the inner side of the special-shaped retainer and the side wall of the sleeve. According to the special-shaped drill bit, the drill bit can smoothly pass through a deformation area of a pile casing, the diameter of a follow-up drill hole meets the requirement, cost is low, and safety is high.

A formwork panel comprising a formwork face comprising at least one passage orifice configured to receive a spacer device, formwork panel characterized in that it comprises at least one sealing device (4) configured to be mounted in an attached manner to a periphery of the passage orifice, the sealing device (4) comprising a support member (40) comprising an annular groove (41) in which an O-ring (42) with an expansion clearance is mounted, the O-ring (42) comprising an internal diameter configured to expand between a minimum diameter of between 16mm and 26mm and a maximum diameter of between 23mm and 33mm. Abstract figure: Figure 6