ADJUSTABLE LEVELLING PAD

An adjustable levelling pad includes a first component provided with first screw threads, a second component provided with second screw threads cooperating with the first screw threads of the first component and a third component having a bearing surface cooperating with the first component. The thread entrance angle of the second screw threads of the second component is less than 35°.

This application claims priority to German patent application no. 10 2021 102 113.8 filed on Jan. 29, 2021, the contents of which are fully incorporated herein by reference.

TECHNOLOGICAL FIELD

The present disclosure is directed to a system configured for use as an adjustable levelling support or pad for connecting a frame of a machine to a support. The disclosure further relates to an assembly comprising a piece of machinery, a support and an adjustable pad, wherein the piece of machinery is mounted to the support by means of the adjustable pad.

BACKGROUND

Adjustable levelling pads are generally configured to provide both support and vertical alignment capability with or without an associated anchor bolt.

Adjustable pads are well known in the art.

Reference can be made toFIGS. 1A and 1Bwhich illustrates a known adjustable levelling pad10.

The adjustable levelling pad10is mounted to connect the frame1of a machine to a foundation or support2, for example constructed from concrete or steel. Anchoring the frame1of the machine to the support2is here done with an anchor bolt3.

The adjustable levelling pad10comprises a first component11or shaft element, a second component12or annular element and a third component13or bearing element. The first, second and third components11,12,13are coaxial along a vertical axis Z-Z′.

The first component11comprises an upper portion11aand a lower portion11b.The lower portion11bhas a cylindrical outer wall provided with an outer screw thread11c.The upper portion11ahas an outer diameter greater than the outer diameter of the lower portion11bso as to form an annular flange. As illustrated ofFIG. 1B, the upper portion11ahas a partial upper surface11dof concave shape. The upper surface11dis rotationally symmetrical.

The first component11has a first through-hole14for accommodating a shank3aof the bolt3.

The second component12has a second through-hole with a cylindrical wall12aprovided with an inner screw thread12bconfigured to engage with the outer screw thread11cof the lower portion11bof the first component11.

The threaded portions11c,12bcooperate together and provide a vertical adjustment.

The third component13sits between the frame1of the machine and the upper portion11aof the first component11.

As shown inFIG. 1B, the third component13has a lower surface13aengaging with the upper surface11dof the upper portion11aof the first component11. The lower surface13ahas a convex shape and is rotationally symmetrical.

The lower surface13aand the upper surface11dare complementarily shaped so as to facilitate slight adjustment of the positions between the first component11and the third component13relative to one another, for example, in order to accommodate slight deviations between the piece of machinery1and the support2.

The third component13has a through hole16having a diameter larger than the diameter of the first through-hole14in order to allow the shank3aof the bolt3to pass through if an axis of symmetric of the lower surface11dof the first component11is not aligned with an axis of symmetry of the lower surface13aof the third component13in order to accommodate deviations from horizontal, parallel orientations of the piece of machinery1and the support2.

The adjustable levelling pad10is sandwiched between the frame1of the machine and the support2and securely held in place by the bolt3and a nut4screwed on a part of the shank3aextending beyond the piece of machinery1. The height H of the adjustable levelling pad10is adjusted by means of screwing the first component11further into or further out of the second component12.

As shown, the outer surface of the upper portion11ahas a specific profile, here blind holes arranged on the circumference of the outer surface, in order to be gripped by the operator. Such specific profile enables the operator to apply a torque to the first component11.

Alternatively, the upper portion11aof the first component11may have a polygonal outer circumference (not shown), for example, square or hexagonal, in a plane substantially perpendicular to an axis of the outer screw thread11c.

Similarly, in order for an operator to apply a torque to the second component12, the second component has a specific profile, here blind holes arranged on the circumference of the outer surface.

When installed, the adjustable levelling pad10is subjected to a mechanical load as a result of the weight of the frame1of the machine, and also as a result of reaction forces transmitted by the support2and/or by the frame1of the machine1.

The maximum magnitude of the mechanical load carried by the known adjustable levelling pad10depends on the strength of the connection between the first component11and the second component12. The maximum mechanical load is determined by the screwed connection between the first and second components11,12, which depends on the pitch of inner screw thread12band the outer screw thread11cand on an engaging area over which the inner screw thread12band the outer screw thread11care engaged.

Such known adjustable pads have a limited load capacity due to the shear strength of the screw threads that provide the vertical alignment for the pad. Consequently, in order to overcome such disadvantage, adjustable pads have large diameters to provide enough cross-sectional area at the base of the threads in order to resist the weight of the machine being supported, the preload from the anchor bolt, and the shaking forces, such as wind loads or seismic loads.

SUMMARY

An aspect of the present disclosure is to provide an improved adjustable levelling pad in which the load capacity of the adjustable pad is increased.

An adjustable levelling pad according to the present disclosure may comprise: a first component or shaft element provided with first screw threads; a second component or lower adjustable part having second screw threads cooperating with the first screw threads of the first component; and a bearing element or third component having a bearing surface cooperating with the first component.

The thread entrance angle of the second screw threads of the second component is less than 35°, preferably equal to 30°. Such thread entrance angle increases the number of threads engaged.

Furthermore, the load path of the load on the third component is transferred to the first component and depends on the thread diameter of the second threads of the second component.

Advantageously, the thread start angle of the first screw threads of the first component is greater than 40°, preferably equal to 45°. Such thread angle may increase the number of threads engaged. Furthermore, such thread angle may reduce the height of the first component, notably its upper portion.

For example, the length of the thread start angle of the first threads of the first component is smaller or equal to 1.5 mm.

For example, the length of the thread entrance angle of the second threads of the second component is less than 1 mm, preferably equal to 0.866 mm.

In an embodiment, the third component has a third height comprised between 2 mm and 8 mm.

The second component has, for example, a second height comprised between 17 mm and 50 mm, allowing more threads to be engaged, and thus increasing the load capacity of the adjustable pad. For example, the outer diameter of the second component may be between 58 mm and 248 mm. The outer diameter of the third component may be between 52 mm and 210 mm.

In an embodiment, the first component comprises a first portion and a second portion having an outer diameter greater than the outer diameter of the first portion, the first portion being provided with the first screw threads.

For example, the upper portion of the first component has a first height between 11 mm and 17 mm.

The ratio between the outer diameter of the second portion of the first component and the outer diameter of the second component is between 0.81 and 0.96.

In an embodiment, the first component is movable compared to the second component between a partially screwed position, in which the threads of the first component partially cooperate with the threads of the second component, and a fully screwed position, in which the first component, notably its second portion, axially contacts an upper surface of the second component.

The height of the adjustable levelling pad is thus adjusted by means of screwing the first component further into or further out of the second component between a minimal total height and a maximal total height. Indeed, by rotating the first component with respect to the second component, the vertical distance bridged by the adjustable pad can be set as desired.

For example, the third component has a convex bearing surface configured to cooperate with a first concave surface of the first component. In an alternative, the bearing surface of the third component may be concave and configured to cooperate with a first convex surface of the first component.

In a general way, the lower surface of the third component and at least a part of the upper surface of the first component may have complementarily shapes so as to facilitate slight adjustment of the positions between the first component and the bearing element relative to one another, for example, in order to accommodate slight deviations from the piece of machinery and the support.

The radius of curvature of the lower surface of the third component corresponds to the radius of curvature of the upper surface of the first component.

For example, the third component further has a substantially planar upper bearing surface configured to support the frame of the machine. The third component is thus able to move with respect to the first component allowing the inclination of the upper surface to be adjusted with respect to the bottom surface of the frame of the machine so that flat contact of the lower surface of the second component on the support can be achieved, as well as flat contact of the upper surface of the third component with the bottom surface of the frame of the machine to be supported.

In an embodiment, the surface of the first component cooperating with the lower surface of the third component is connected to its outer circumferential surface via a flat surface. In other words, the upper surface of the first component comprises a surface cooperating with the lower surface of the third component and a flat surface.

For example, the second component is radially delimited by an inner cylindrical wall and an outer cylindrical wall and axially by a lower surface and an upper surface.

The inner wall of the second component forms a second through-hole having a diameter for receiving, for example, a shank of a bolt. The bolt may be a standard bolt having a shank and a threaded part; for a fitted bolt, the shank may have a diameter greater than the diameter of the threaded part.

The third component may be radially delimited by an outer cylindrical wall and an inner cylindrical wall forming a third through hole receiving the shank of the bolt.

As a non-limiting embodiment, for a bolt having a metric size M20, the outer diameter of the screw threads of the first component is of 64 mm with a pitch of 1.5 mm, the outer diameter of the upper portion of the first component is equal to 86 mm and the height of the upper portion is equal to 14 mm. In this case, the third height of the third component is equal to 3 mm and its outer diameter is equal to 80 mm. The second height of the second component is equal to 23 mm and its outer diameter is equal to 98 mm.

In another non limiting example, for a bolt having a metric size M24, the outer diameter of the screw threads of the first component is of 82 mm with a pitch of 2 mm, the outer diameter of the upper portion of the first component is equal to 103 mm and the height of the upper portion is equal to 14 mm. In this case, the third height of the third component is equal to 4 mm and its outer diameter is equal to 97 mm. The second height of the second component is equal to 27 mm and its outer diameter is equal to 118 mm.

In another non limiting example, for a bolt having a metric size M48, the outer diameter of the screw threads of the first component is of 150 mm with a pitch of 3 mm, the outer diameter of the upper portion of the first component is equal to 178 mm and the height of the upper portion is equal to 17 mm. In this case, the third height of the third component is equal to 6 mm and its outer diameter is equal to 170 mm. The second height of the second component is equal to 42 mm and its outer diameter is equal to 218 mm.

In the embodiment where the outer diameter of the third component is greater than the outer diameter of the upper portion of the first component, in the case of a bolt of size M24, the height adjustment range of the adjustable pad is comprised between 26 mm and 36 mm.

This allows to cover the gap of the adjustment ranges in known adjustable pads. Indeed, in known standard adjustable pads as shown onFIGS. 1A and 1B, the adjustment range is comprised between 45 mm to 60 mm. In known called “low profile” adjustable pads, where the first component does not comprise an upper flange having an outer diameter greater than the diameter of the screw portion, the adjustment range is comprised between 20 mm to 30 mm. There is thus a gap in the range from 30 mm to 45 mm.

Thanks to the combination of the thread entrance angle and thread start angle as described above, with a third component having an outer diameter greater than the outer diameter of the upper portion of the first component, the gap in the range is significantly reduced.

In an embodiment, the adjustable pad comprises a protection cap fastened to the first component and extending towards the second component, the protection cap at least partially surrounds the second component and is configured to cooperate in a sealing manner with the second component. As a result, foreign matters may be prevented from gathering in the screw threads of the first and second components.

The phrase “cooperating in a sealing manner” means that the protection cap substantially prevents the infiltration of liquids, particles and dust from the external environment into the threaded joint formed by the first and second screw threads.

In an embodiment, the protection cap may be in radial contact with the outer circumference of the second portion. As an alternative, a radial gap may exist between the protection cap and the outer circumference of the second portion, defining a sealing by narrow passage, or a labyrinth seal.

The protection cap is advantageously configured to slide freely along the outer circumference of the second component when the first component is moved between the partially screwed position and the fully screwed position. In other words, when the first component rotates compared to the second component, the protection cap slides along the cylindrical outer circumference of the second component.

For example, the protection cap may be mounted in an annular groove provided on the circumference of the first component, notably its second portion. The annular groove of the second portion of the first component is, for example, located at the vicinity of its lower end. Alternatively, the annular groove could be provided on the outer wall at a distance of the lower end of the second portion.

For example, the protection cap may comprise an annular mounting portion fastened to the first component and an annular protection flange extending towards the second component and radially surrounding in a sealing manner the outer circumference of the second component.

Advantageously, the mounting portion extends axially along an axis substantially parallel to an outer wall of the first component, notably its second portion, and the annular protection flange extends axially along an axis substantially parallel to the outer wall of the second component, the annular protection flange being connected to the annular mounting portion by a connecting portion.

For example, the connecting portion of the protection cap may extend along an axis inclined relative to an axis perpendicular to the annular protection flange. For example, the axis of the connecting portion may form an angle between 1° and 10° with the axis perpendicular to the annular protection flange.

The annular protection flange may have an outer diameter greater than the outer diameter of the mounting portion and slightly greater than the outer diameter of the second component.

The protection cap may be made of plastic material, for example for example polymeric material, such as polyether ether ketone (PEEK) or any thermoplastic polymer, etc.

In an embodiment, the outer wall of the second component comprises an annular recess receiving the annular protection flange of the protection cap. The protection cap is thus configured to slide along the of the second component until abutting at the lower end of the recess. The recess forms a height indicator.

The annular protection flange may have an inner diameter slightly greater than the outer diameter of the annular recess. The protection cap and the first and second components define an annular closed space.

“Slightly greater” means that the annular protection flange may slide along the outer circumference of the second component when the first and second components are screwed relative to one another while maintaining a radial contact with the circumference in order to form an obstacle to the penetration of outer particles into the threaded joint.

The annular protection flange of the cap may be flexible so that when the first component is screwed totally into the second component, the flange deforms elastically in order to slide along the outer wall of the second component. The annular protection flange is thus capable, from the material used and/or its dimension, to be deformed under a slight force and to return to its initial position when no force is exerted on the protection flange.

In an embodiment the protection cap is overmolded on the first component or may be mounted from the top once the first component is threaded in the second component.

In an embodiment the adjustable pad comprises a mechanical limiter fastened to the outer circumference of the first component, notably in a recess in the first portion, and configured to abut axially against a shoulder provided on the inner wall of the second component when the first component is unscrewed from the second component, which avoids the first component from becoming detached from the second component.

The mechanical limiter is, for example, fastened at the lower end of the first component.

The mechanical limiter may be annular and mounted in an annular recess.

Alternatively, the pad may comprise two or more mechanical limiters, such as slugs arranged regularly on the circumference of the second portion of the first component.

The outer diameter of the mechanical limiter may be greater than the inner diameter threaded wall of the second component and less than the inner diameter of the shoulder of the second component.

In an embodiment, the adjustable pad comprises an annular sealing element fastened in an annular groove provided on the threaded wall of the second component, for example at the upper end of the second component or at an axial distance from the upper end. The annular sealing element is deformable and configured to deform over the threads between an initial position and a radially compressed position when the first component is mounted in the second component.

The annular sealing element is configured to increase friction with the first component. The inner diameter of the annular sealing element may be slightly less than the outer diameter of the screw threads of the first component, so that the annular sealing element is deformed when screwing the first component in the second component and is radially compressed against the outer screw threads of the first component, which locks the first component against the second component.

Indeed, when the first component is screwed into the second component, the screw threads of the first component do not cut into the annular sealing element, but rather the sealing element deforms as it moves over the threads.

The annular sealing element may be, as a non-limiting example, elastically deformable.

By “deformable”, it is meant that the element is capable, from the material used and/or its dimension, to be deformed under a slight force and to return to its initial position when no force is exerted on the element.

In another embodiment, the annular sealing element may be, for example, made of polymeric material, such as nylon or other materials capable of increasing friction on the screw thread.

For example, the annular sealing element acts as a locking element increasing friction between the first and second components. The annular sealing element may be, for example an O-ring.

In an embodiment, the inner wall of the second component may comprise a shoulder provided with an inner screw thread configured to engage with the outer screw thread of the lower portion of the first component.

The inner diameter of the shoulder may be less than the inner diameter of the inner wall and greater than the outer diameter of the first portion of the first component.

The outer diameter of the outer cylindrical wall of the second component may be greater than the outer diameter of the second portion of the first component.

The outer wall of the second component is provided with an annular recess having an outer diameter advantageously less than the outer diameter of the outer wall.

The adjustable pad is advantageously made in steel, preferably of C45 carbon steel.

According to another aspect, the disclosure further relates to an assembly comprising a piece of machinery, a support and an adjustable pad as described before, wherein the piece of machinery is mounted to the support by means of the adjustable pad.

DETAILED DESCRIPTION

The expressions “outer” and “inner” refer to the longitudinal axis Z-Z′ of the adjustable levelling pad100, the inner parts being closer to the axis than the outer parts.

The adjustable levelling pad100is mounted to connect a frame1of a machine to a foundation or support2, for example constructed from concrete or steel. Anchoring the frame1of the machine to the support2is here done with an anchor bolt3.

The adjustable levelling pad100comprises a first component110or shaft element, a second component120or lower adjustable part and a third component130or bearing element. The first, second and third components110,120,130are coaxial along a vertical axis Z-Z′.

The adjustable levelling pad100is symmetrical relative to the longitudinal axis Z-Z′.

The first component110, shown in details onFIG. 4, comprises a lower portion111and an upper portion112.

The lower portion111has a cylindrical outer wall111aprovided with an outer screw thread111b.As illustrated, the outer screw thread111bhas a height H5.

The upper portion112has an outer diameter OD2greater than the outer diameter OD1of the lower portion111so as to form an annular flange. For example, the outer diameter OD2of the upper portion112is comprised between 56 mm and 218 mm. The upper portion112has a first height H1. For example, the first height H1of the upper portion112is between 11 mm and 17 mm. The upper portion112has a cylindrical outer wall112aprovided with an annular groove112bat the vicinity of its lower end.

Alternatively, the annular groove112bcould be provided on the outer wall112aat a distance from the lower end of the upper portion112. Alternatively, the upper portion112may not comprise the annular groove112b.

As illustrated ofFIG. 4, the upper portion112has an upper surface112cat least partly of upwardly concave shape. The upper surface112cis rotationally symmetrical. The upper surface112cis connected to the cylindrical outer wall112aby a substantially flat surface112d.

The first component110has a first through-hole113extending axially from the upper surface112cto the lower surface114of the first component110. The first through-hole113has an inner diameter ID1configured for accommodating a shank3aof the bolt3.

As illustrated onFIG. 2A, the bolt3comprises shank3aand a threaded part3b,for fitted bolts, the shank3ahaving a diameter greater than the diameter of the threaded part3b.

The metric screw thread OD1of the lower portion111of the first component is between 42 mm and 190 mm for a bolt size between 12 mm and 64 mm.

The thread start angle α3of the outer screw threads111bof the first component110is greater than 40°, preferably equal to 45°, and for example less than 55°. Such thread angle may increase the number of threads engaged.

The length L2of the thread start angle of outer screw threads111bof the first component110is smaller or equal to 1.5 mm.

The second component120, shown in details onFIGS. 3A and 3B, is radially delimited by an inner cylindrical wall121and an outer cylindrical wall122and axially by a lower surface123and an upper surface124. The inner wall121is provided with an inner screw threads configured to engage with the outer screw threads111bof the lower portion111of the first component110. The inner threads121have an inner diameter ID2. The threaded portions111b,121cooperate together and provide a vertical adjustment.

The thread entrance angle α2of the inner screw threads121of the second component120is less than 35°, preferably equal to 30°, for example greater than 25°. Such thread entrance angle increases the number of threads engaged.

Furthermore, the load path of the load on the third component130is transferred to the first component110and depends on the thread diameter of the second threads121of the second component120.

The length L1of the thread entrance angle α2of the inner screw threads121of the second component120is less than 1 mm, preferably equal to 0.866 mm, and the width W1is, for example, less than 1.5 mm.

As shown onFIG. 3a, the upper surface124of the second component120comprises a first planar surface124a,a second tapered surface124band a rounded surface124cconnecting the tapered surface124bto the outer cylindrical wall122.

The second tapered surface124btapers in the radial outward direction at an angle α1relative to an axis perpendicular to the vertical axis Z-Z′ bigger or equal to 10°, for example bigger or equal to 15°.

The radius of curvature R1connecting the planar surface124ato the tapered surface124bis, for example, equal to 6 mm.

The radius of curvature R2of the rounded surface124cis, for example, greater than 2 mm, for example between 2 mm and 4 mm, for example equal to 3 mm. The center of the radius of curvature R2is at a distance H4from the planar surface124a.The distance H4is for example equal to 4.5 mm.

The outer diameter OD3of the outer cylindrical wall122of the second component120is greater than the outer diameter OD2of the upper portion112of the first component110. For example, the outer diameter OD3of the outer cylindrical wall122of the second component120is between 58 mm and 248 mm.

The ratio between the outer diameter OD2of the upper portion112of the first component110and the outer diameter OD3of the second component120is between 0.81 and 0.96.

The outer cylindrical wall122of the second component120has a second height H2. For example, the second height H2of the second component120is between 17 mm and 50 mm.

The first component110is movable relative to the second component120between a partially screwed position, shown onFIG. 2A, in which the threads111bof the first component110partially cooperate with the threads121of the second component120and a fully screwed position, not shown, in which the lower surface of the upper portion or flange112of the first component110axially contacts the upper surface124of the second component120.

The third component130sits between the frame1of the machine and the upper portion112of the first component110. As shown inFIGS. 2A and 2B, the third component130has a lower surface131engaging with the upper surface112cof the upper portion112of the first component110. The lower surface131has a convex shape and is rotationally symmetrical.

The lower surface131and the upper surface112care complementarily shaped so as to facilitate slight adjustment of the positions between the first component110and the third component130relative to one another, for example, in order to accommodate slight deviations between the piece of machinery1and the support2.

The radius of curvature of the lower surface131of the third component130corresponds to the radius of curvature of the upper surface112cof the first component110.

The third component130further has a substantially planar upper bearing surface132configured to support the frame1of the machine. The third component130is thus able to move with respect to the first component110allowing the inclination of the upper surface132to be adjusted with respect to the bottom surface of the frame1of the machine, so that flat contact of the lower surface123of the second component120on the support2can be achieved, as well as flat contact of the upper surface132of the third component with the bottom surface of the frame1of the machine to be supported.

The third component130is radially delimited by an outer cylindrical wall133and an inner cylindrical wall134forming a third through hole receiving the shank3aof the bolt3. The third through-hole134has a diameter ID4larger than the diameter ID1of the first through-hole113in order to allow the shank3aof the bolt3to pass through if an axis of symmetry of the upper surface112cof the first component110is not aligned with an axis of symmetry of the lower surface131of the third component130in order to accommodate deviations from horizontal, parallel orientations of the frame1of the machine and the support2.

The outer cylindrical wall133of the third component130has an outer diameter OD5greater than the outer diameter OD1of the lower portion111of the first component110and less than the outer diameter OD2of the flange112of the first component110. This provides a relatively wide range of inclinations for adjusting the inclination of the adjustable pad, even when the first component110has been completely screwed into the second component120.

The outer diameter OD5of the third component130is between 52 mm and 210 mm.

As illustrated, the adjustable levelling pad100is sandwiched between the frame1of the machine and the support2and securely held in place by the bolt3and a nut4screwed on a part of the shank3aextending beyond the machine1.

The height H3of the third component130corresponds to the height of the outer wall133extending axially beyond the upper portion112of the first component110.

The height H of the adjustable levelling pad100is adjusted between a minimal total height and a maximal total height by means of screwing the first component110further into or further out of the second component120. Indeed, by rotating the first component110with respect to the second component120, the vertical distance bridged by the adjustable pad100can be set as desired.

The outer wall112aof the first component110and the outer wall122of the second component120may each be provided with fastening blind holes or recesses, designed to cooperate with a suitable tool for screwing and unscrewing the first component110relative to the second component120.

The first, second and third components110,120,130are made, for example, of steel, preferably high-grade steel.

Another embodiment of an adjustable pad shown onFIGS. 5A and 5B, in which the same elements bear the same reference numerals, differs from the adjustable pad ofFIGS. 2A and 2Bonly by the fact that the heights respectively of the first component110′ and of the second component120′ are reduced compared to the heights of the first component110and of the second component120shown inFIGS. 2A and 2B, and by the fact that the first component110′ does not include an upper portion112extending radially beyond the threaded portion111b′.

As shown onFIGS. 5A and 5B, the outer diameter OD5of the third component130is greater than the outer diameter OD1′ of the first component110′.

Furthermore, the adjustment range between the minimal total height Hmin and the maximal total height Hmax is here between 26 mm to 36 mm.

Another embodiment of an adjustable pad shown onFIG. 6, in which the same elements bear the same reference numerals, differs from the adjustable pad ofFIGS. 2A and 2Bonly by the fact that the adjustable pad100further comprises a cylindrical protection cap140fastened to the first component110, notably in an annular groove112bprovided on the circumference of the flange112of the first component110, and extending towards the second component120.

As illustrated, the protection cap140surrounds partially the annular recess128of the second component120.

Alternatively, the outer wall122of the second component120may not comprise the annular recess128. In this case, the protection cap140surrounds partially the outer wall122of the second component120.

The protection cap140comprises an annular mounting portion141fastened in the annular groove112bof the first component110and an annular protection flange142designed to surround the outer circumference of the second component120.

The annular protection flange142of the protection cap140cooperates in a sealing manner with the outer circumference of the second component120, preventing the infiltration of liquids, particles and dust from the external environment into the threaded joint formed by the first and second screw threads.

As illustrated, the annular protection flange142is in radial contact with the outer circumference of the second portion120.

As an alternative, a radial gap may be provided between the protection cap140and the outer circumference of the second portion120, defining a sealing by narrow passage, or a labyrinth seal.

The mounting portion141extends axially along an axis substantially parallel to the outer wall112aof the flange112of the first component110.

The annular protection flange142extends axially along an axis substantially parallel to the outer wall112aof the flange112of the first component110.

The annular protection flange142is connected to the annular mounting portion141by a connecting portion143. The connecting portion143extends along an axis inclined relative to an axis perpendicular to the annular protection flange142. For example, the axis of the connecting portion143forms an angle comprised between 1° and 10° with the axis perpendicular to the annular protection flange142.

The annular protection flange142has an outer diameter greater than the outer diameter of the mounting portion141and slightly greater than the outer diameter of the second component120.

The protection cap140is made of plastic material, for example for example polymeric material, such as polyether ether ketone (PEEK) or any thermoplastic polymer, etc. The protection cap140may be overmolded on the first component110or may be mounted from the top once the first component110is threaded in the second component120. Alternatively, the protection cap140may be fixed to the first component110.

When the first component110rotates compared to the second component120, the protection cap140slides along the cylindrical outer circumference of the second component120. The protection cap140is configured to slide along the annular recess128of the second component120until abutting at the lower end of the recess128. The recess128forms a height indicator.

The annular protection flange142has an inner diameter slightly greater than the outer diameter OD4of the annular recess128.

The protection cap140and the first and second components110,120define an annular closed space.

By “slightly greater”, it is meant that the annular protection flange142may slide along the outer circumference of the second component120when the first and second components are screwed relative to one another, but maintains a radial contact with the circumference in order to form an obstacle to the penetration of outer particles into the threaded joint. As a result, foreign matters may be substantially prevented from gathering in the screw threads of the first and second components110,120.

The annular protection flange142of the cap140is flexible so that when the first component110is screwed completely into the second component120, the flange142deforms elastically in order to slide along the outer wall122of the second component120. The annular protection flange142is thus capable, from the material used and/or its dimension, to be deformed under a slight force when and to return to its initial position when no force is exerted on the protection flange142.

Another embodiment of an adjustable pad shown onFIG. 7, in which the same elements bear the same reference numerals, differs from the adjustable pad ofFIG. 6only by the fact that the adjustable pad comprises an annular sealing element160and a mechanical height limiter150and that the inner wall126of the second component120comprises a shoulder125provided with inner threads121. The inner diameter ID2of the inner threads121is less than the inner diameter ID3of the inner wall126.

The annular sealing element160is fastened in an annular groove127provided on the threaded wall121of the second component120at the upper end of the second component120. Alternatively, the annular sealing element160may be fastened on the inner threaded wall121the second component120at an axial distance from the upper end of the second component120. This annular sealing element160is deformable, for example elastically, between an initial position and a radially compressed position when the first component110is mounted in the second component120.

The annular sealing element160is configured to increase friction with the first component110. The inner diameter of the annular sealing element160is slightly less than the outer diameter OD1of the screw threads111bof the first component110, so that the annular sealing element160is deformed when screwing the first component110in the second component120and is radially compressed against the outer screw threads111bof the first component110, which locks the first component110against the second component120.

Indeed, when the first component110is screwed into the second component120, the screw threads111bof the first component110do not cut into the annular sealing element160, but rather the sealing element160deforms when passing over the threads.

The annular sealing element160acts as a locking element increasing friction between the first and second components110,120. The annular sealing element160is, for example an O-ring. The annular sealing element160is for example, made in polymeric material, such as nylon or other materials capable of increasing friction on the screw thread.

The mechanical limiter150is fastened to the outer circumference111aof the upper portion111of the first component110, notably in a recess115. The mechanical limiter150is fastened at the lower end of the first component110. The mechanical limiter150is here annular and mounted in an annular recess115. Alternatively, the pad100may comprises two or more segments of mechanical limiters arranged regularly on the circumference of the upper portion of the first component110.

The outer diameter of the mechanical limiter150is greater than the inner diameter of threaded wall121of the second component120and less than the inner diameter of the shoulder125of the second component120, so that when the first component110is unscrewed from the second component120, the mechanical limiter150is configured to abuts axially against the shoulder125of the second component120, which avoid the first component110to be detached from the second component120.

After installation of the first component110in the second component120, the mechanical limiter150is mounted from the bottom in the recess115.

As shown onFIG. 7, the adjustable pad100combines the use of a protection cap140, an annular sealing element160and mechanical limiter150. Alternatively, the adjustable pad100may comprise the protection cap140and/or the mechanical limiter150, and/or the sealing element160.

In all embodiments, the adjustable pad may be made in steel, for example C45 carbon steel.

It should be noted that the adjustable pad has been described with reference to exemplary embodiments in which the first component is provided with an outer screw thread and a second component provided with an inner screw thread. However, the invention also relates to embodiments in which the outer circumference of the second component is provided with an outer screw thread and the first component comprises an inner screw thread. In such embodiment, the first component may be provided with a flange and the protection cap may be fastened to the flange and extend towards the second component. Thanks to the invention, the load capacity of the adjustable pad is increased. Moreover, weight of the adjustable pad is reduced and adjustment range is increased.