WO2012146266A1

WO2012146266A1 - Adjustable chock with height limiter

Info

Publication number: WO2012146266A1
Application number: PCT/EP2011/002151
Authority: WO
Inventors: René VERMEULEN; Dick VOGELAAR; Bram HOOGHART
Original assignee: Skf B.V.
Priority date: 2011-04-29
Filing date: 2011-04-29
Publication date: 2012-11-01

Abstract

An adjustable chock comprises a first component (106) having an external screw thread (114), and a second component (108) having an internal screw thread (128) configured for engaging with the external screw thread of the first component. The external screw thread and the internal screw thread engage over a distance (140), determined in an axial direction parallel to a common axis of the internal screw thread and the external screw thread. The distance can be adjusted by rotating the first component relative to the second component while the internal screw thread and the external screw thread remain engaged. The chock comprises a mechanical limiter (302, 306, 308, 310) configured to mechanically limit a lower bound of the distance to a pre-set value while the internal screw thread and the external screw thread remain engaged.

Description

ADJUSTABLE CHOCK WITH HEIGHT LIMITE

FIELD OF THE INVENTION

The invention relates to a system configured for use as an adjustable chock for connecting a piece of machinery to a support. The invention further relates to a further system, comprising a piece of machinery, a support and an adjustable chock, wherein the piece of machinery is mounted to the support by means of the adjustable chock

BACKGROUND ART

Adjustable chocks are well known in the art. See, for example, US patent 7,438,274, issued to Rene Vermeulen for "Adjustable foot for setting up equipment in alignment" and incorporated herein by reference, and US patent 6,068,234, issued to Elbert Keus for "Setting foot provided with sealing means", and incorporated herein by reference. Typically, an adjustable chock comprises a first component having an external screw thread, and a second component having an internal screw thread configured for engaging with the external screw thread of the first component. A distance, over which the external screw thread and the internal screw thread are engaging, is adjustable by means of rotating the first component and the second component relative to one another while the internal screw thread and the external screw thread are engaged. The concept "distance" as used herein may be interpreted as, e.g., the length of the helical path, along which the internal screw thread and the external screw thread of given pitch are engaged. Alternatively, the distance may be interpreted, e.g., as a length of the extent over which the internal screw thread and the external screw thread overlap, as measured in a direction along a common axis of the internal screw thread and of the external screw thread.

SUMMARY OF THE INVENTION

When installing and adjusting the adjustable chock, the first component and the second component are rotated relative to one another so as to have the adjustable chock assume the proper height in order to bridge the gap between the piece of machinery and the support. The distance, as specified above, is indicative of this height. The inventor has recognized that, for safety reasons, it is advisable that the installer of the adjustable chock be informed about the allowable distance having reached a lower limit. If the height of the adjustable chock is increased any further, the distance, over which the internal screw thread and the external screw thread remain engaged, decreases below a threshold value. The threshold value is the minimum length over which the internal screw thread and the external screw thread are advised to remain engaged, given the magnitude of the mechanical load the adjustable chock is to carry in operational use.

Therefore, the inventor proposes a system configured for use as an adjustable chock for connecting a piece of machinery to a support. The adjustable chock comprises a first component having an external screw thread, and a second component having an internal screw thread. The internal screw thread is configured for engaging with the external screw thread of the first component. The external screw thread and the internal screw thread engage in operational use of the adjustable chock over a distance, determined in an axial direction parallel to a common axis of the internal screw thread and the external screw thread. The distance is adjustable by means of rotating the first component and the second component relative to one another while the internal screw thread and the external screw thread remain engaged. The adjustable chock comprises a mechanical limiter configured to mechanically limit a lower bound of the distance to a pre-set value while the internal screw thread and the external screw thread remain engaged.

Accordingly, the mechanical limiter is configured for mechanically limiting the maximum height of the adjustable chock. The maximum height is associated with the minimum distance over which the internal screw thread and the external screw thread engage. Mechanically limiting may result in the installer receiving a tactile feedback while attempting to rotate the first component and the second component relative to one another in order to go beyond the maximum allowed height. The tactile feedback may manifest itself, e.g., through a sudden increase in mechanical resistance to further rotating the first component and the second component relative to each other in the direction of increasing height of the adjustable chock.

The expression "system configured for use as an adjustable chock" is meant to cover both an assembled adjustable chock as well as a kit of parts that are to be assembled to create the adjustable chock.

In an embodiment of the above system, the mechanical limiter comprises a first limiter part and a second limiter part. The first limiter part is configured for being stationary in the axial direction with respect to the first component. The second limiter part is configured for being stationary in the axial direction with respect to the second component. The first component has a first through- hole coaxial with the external screw thread. The first limiter part comprises a recess in a wall of the first through-hole. The second limiter part has a portion that extends into the recess in operational use of the adjustable chock. The pre-set value of the lower bound is determined by a position of the recess in the wall in the axial direction and by a length of the recess in the axial direction.

The first through-hole is configured for accommodating a shank of a bolt in operational use of the adjustable chock. The recess and the extending portion of the second limiter part are configured to allow the extending portion to travel relative to the first component and within the recess during the adjusting of the adjustable chock. The travel of the extending portion within the recess is limited by the boundary of the recess. When the extending portion hits the boundary during adjusting of the adjustable chock, the installer experiences a sudden increase in resistance to further rotating the first component and the second component relative to one another, thus supplying a tactile signal to the installer that a safety limit has been reached.

The location of the boundary of the recess may be determined in advance in dependence on the maximum magnitude of the mechanical load that the adjustable chock is expected to carry in operational use of the adjustable chock. Alternatively, the recess has a standardized dimension in the axial direction, and a dimension in the axial direction of the extending portion of the second limiter part may be selected in advance and in dependence on the expected maximum mechanical load. Selecting the proper species of the second limiter part, on the basis of the axial dimension of the associated extending portion, co-determines the pre-set value of the lower bound of the distance, over which the internal screw thread and the external screw thread remain engaged.

Various ways of creating the recess, and various embodiments of the first limiter part and the second limiter part, are discussed below with reference to the accompanying drawings.

In a further embodiment of a system of the invention, the first component comprises an upper portion and a lower portion. The lower portion accommodates the external screw thread. The mechanical limiter comprises a first limiter part and a second limiter part. The first limiter part comprises a first hooking device attached to a first outer perimeter of the upper portion. The second limiter part comprises a second hooking device attached to a second outer perimeter of the second component. The pre-set value of the lower bound is reached when the first hooking device and the second hooking device hook into each other.

Each respective one of the first hooking device and the second hooking device may be formed as a respective ring. The respective rings overlap in order to provide the hooking functionality. The respective rings may serve as a visual height-indicator and/or as a protective sleeve to protect the exposed portion of the external screw thread against contamination. Various implementations of the first hooking device and the second hooking device are discussed below with reference to the accompanying drawings.

In a further embodiment of the system, the mechanical limiter comprises a first limiter part and a second limiter part. The first limiter part is accommodated at one of the first component and the second component. The second limiter part is accommodated at the other one of the first component and the second component. The first limiter part comprises a spring-loaded catch, and the second limiter part comprises a hole. The hole is configured for engaging with the spring- loaded catch when the spring-loaded catch and the hole are aligned. The pre-set value of the lower bound is reached when the spring-loaded catch and the hole engage.

In an embodiment using the spring-loaded catch, the spring-loaded catch is configured for operating in a direction that does not intersect the common axis. The direction then has a tangential vector component, i.e., a vector component perpendicular to the axial direction and perpendicular to a radial direction. A radial direction is a direction in a plane perpendicular to the axial direction and along a line that intersects the common axis (of the internal screw thread and the external screw thread, as discussed above). An orientation of the spring-loaded catch with a non-zero tangential vector component facilitates retrieval of the spring-loaded catch from the hole when increasing the distance over which the internal screw thread and the external screw thread engage.

In a further embodiment of the system, the adjustable chock comprises a fourth component with a further internal screw thread configured for engaging with the external screw thread of the first component. In operational use of the adjustable chock, the external screw thread and the further internal screw thread engage over a further distance, determined in an axial direction parallel to a common axis of the further internal screw thread and the external screw thread. The further distance is adjustable by means of rotating the first component and the fourth component relative to one another while the further internal screw thread and the external screw thread remain engaged. The adjustable chock comprises a further mechanical limiter configured to mechanically limit a further lower bound of the further distance to a further pre-set value while the further internal screw thread and the external screw thread remain engaged.

In this further embodiment, the adjustable chock enables to adjust the height of the adjustable chock in two independent manners: by means of rotating the first component and the second component relative to each other, and by means of rotating the first component and the fourth component relative to each other. The first component can then be implemented using a section of a hollow threaded rod, which is an inexpensive module. Threaded hollow rods of different lengths can be used with the same second component and the same fourth component.

The invention also relates to a further system comprising a piece of machinery, a support and an adjustable chock connecting the piece of machinery to the support. For example, the further system comprises a seagoing vessel, the piece of machinery comprises an engine for propelling the vessel, and the support comprises a chassis connected to the vessel and configured fro accommodating the engine. The adjustable chock comprises a first component having an external screw thread, and a second component having an internal screw thread configured for engaging with the external screw thread of the first component. The external screw thread and the internal screw thread engage in operational use of the adjustable chock over a distance, determined in an axial direction parallel to a common axis of the internal screw thread and the external screw thread. The distance is adjustable by means of rotating the first component and the second component relative to one another while the internal screw thread and the external screw thread remain engaged. The adjustable chock comprises a mechanical limiter configured to mechanically limit a lower bound of the distance to a pre-set value while the internal screw thread and the external screw thread remain engaged.

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in further detail, by way of example and with reference to the accompanying drawing, wherein:

Figs.1 and 2 are diagrams of a known adjustable chock;

Fig.3 is a diagram of a first adjustable chock according to the invention; Fig.4 is a diagram of a second adjustable chock according to the invention;

Fig.5 is a diagram of a third adjustable chock according to the invention;

Figs.6 and 7are diagrams of a fourth adjustable chock according to the invention;

Figs.8 and 9 are diagrams of illustrating two configurations of the fourth adjustable chock of Figs. 6 and 7;

Fig.10 is a diagram of a fifth adjustable chock according to the invention;

Fig.1 1 is a diagram of a sixth adjustable chock according to the invention;

Figs.12, 13 and 14 are diagrams of a seventh adjustable chock according to the invention;

Fig.15 is a diagram illustrating a further configuration of the fourth adjustable chock of Figs.6 and 7; and

Fig.16 is a diagram of a particular implementation a spring-loaded catch for use in the fourth adjustable chock of Figs.6, 7and 15, for use in the fifth adjustable chock of Fig.10, or for use in seventh adjustable chock of Fig.14. Throughout the Figures, similar or corresponding features are indicated by same reference numerals.

DETAILED EMBODIMENTS

The invention relates to a system designed for use as an adjustable chock for connecting machinery to a support along an axis of the adjustable chock. The system may be made commercially available as an assembled entity of as a kit-of-parts.

Figs. l and 2 are diagrams of a known adjustable chock 100. The diagram of Fig.1 shows a side view of the known adjustable chock 100 in operational use, and the diagram of Fig.2 schematically shows a cross-section of the known adjustable chock 100.

The known adjustable chock 100 is mounted to connect a piece of machinery 102 to a support 104. The known adjustable chock 100 comprises a first component 106, a second component 108 and a third component 110. The first component 106 has an upper portion 11 1 and a lower portion 112. The lower portion 112 has a cylindrical outer wall provided with an external screw thread 1 14. The first component 106 has a first through-hole 116 for accommodating a shank 118 of a bolt 120. The second component 108 has a second through-hole 126 with a cylindrical wall provided with an internal screw thread 128. The internal screw thread 128 is configured for engaging with the external screw thread 114 of the portion 112 of the first component 106. The diagram of Fig.2 indicates in the cross-section a first region 130 and a second region 132 where the internal screw thread 128 and the external screw thread 114 engage. The third component 1 10 sits, in the example illustrated, between the piece of machinery 102 and the upper portion 1 1 1 of the first component 106. The third component 1 10 has a lower surface 134 that engages with an upper surface 136 of the upper portion 111 of the first component 106. The lower surface 134 and the upper surface 136 are complementarily shaped so as to facilitate slight adjustment of the positions of the first component 106 and the third component 1 10 relative to one another, e.g., in order to accommodate slight deviations from the piece of machinery 102 and the support 104 being positioned exactly parallel to one another. The diagram of Fig.2 shows the known adjustable chock 100, wherein the lower surface 134 of the third component 1 10 is convex and rotationally symmetrical, and the upper surface 136 of the first component 106 is concave and rotationally symmetrical. The third component 110 has a third through-hole 138 with a diameter that is somewhat larger than a diameter of the first through-hole 1 16, in order to allow the shank 1 18 of the bolt 120 to pass through if an axis of rotational symmetry of the lower surface 134 is not aligned with an axis of rotational symmetry of the upper surface 136 in order to accommodate the deviations from the horizontal, parallel orientations of the piece of machinery 102 and the support 104.

The known adjustable chock 100 is sandwiched between the piece of machinery 102 and the support 104 and is securely held in place by the bolt 120 and a nut 122. The nut 122 is screwed on a part of the shank 118 of the bolt 120, extending beyond the piece of machinery 102, and is tightened after a height 124 of the known adjustable chock 100 has been properly set. A first washer 121 is located between a head of the bolt 120 and the support 104, and a second washer 123 is located between the nut 122 and the piece of machinery 102. The height 124 of the known adjustable chock 100 is adjusted by means of screwing the first component 106 further into or further out of the second component 108. To this end, each of the first component 106 and the second component 108 is configured for being gripped in order to apply a torque.

For example, in order for an operator to apply a torque to the first component 106, the upper portion 1 1 1 of the first component 106 has a polygonal outer perimeter (not shown) e.g., square or hexagonal, in a plane substantially perpendicular to an axis of the external screw thread 1 14. A square outer perimeter of a normalized size or a hexagonal outer perimeter of a normalized size enables the operator to use normalized open-end wrenches. As another example, an outer surface of the upper portion 1 1 1 that faces substantially radially outwards, relative to the axis of the external screw thread 114, has a specific profile, e.g., serrated in an angular direction, or having one or more radial holes (not shown), so that the outer surface of the upper portion 111 can be gripped by a spanner wrench (US) (or: hook spanner (UK), or pin spanner), or a tommy bar.

Similarly, in order for an operator to apply a torque to the second component 108, the second component 108 has a polygonal outer perimeter (not shown) e.g., square or hexagonal, in a plane substantially perpendicular to an axis of the internal screw thread 128. Alternatively, an outer surface of the second component 108 that faces substantially radially outwards, relative to the axis of the internal screw thread 128, has a specific profile, e.g., serrated in an angular direction, or having one or more radial holes (not shown), so that the outer surface can be gripped by a suitable spanner or a tommy bar.

When installed, the known adjustable chock 100 is subjected to a mechanical load as a result of the weight of the piece of machinery 102, and also as a result of reaction forces transmitted by the support 104 and/or by the piece of machinery 102. For example, the piece of machinery 102 comprises an engine for propelling a seagoing vessel and the support 104 forms part of a structure of the seagoing vessel that accommodates the engine, and that is stationary with respect to the hull of the vessel. The non-uniform motion of the moving parts of the engine gives rise to reaction forces being exerted by the piece of machinery 102 on the support 104 via the known adjustable chock 100. Similarly, the pitching, rolling and yawing of the seagoing vessel as a result of the waves and of the wind cause the support 104 to undergo movements with respect to an inertial frame of reference that are transmitted via the known adjustable chock 100 to the piece of machinery 102.

The maximum magnitude of the mechanical load carried by the known adjustable chock 100 depends on the strength of the connection between the first component 106 and the second component 108. That is, the maximum mechanical load is determined by the strength of the materials used in the first component 106 and in the second component 108, and on the screwed connection between the first component 106 and the second component 108. The strength of the screwed connection depends, in turn, on the pitch of the internal screw thread 128 and of the external screw thread 1 14, and on a surface area of the screwed connection, i.e., on the diameter of the second through-hole 126 and on a segment 140 of the height 124 over which the internal screw thread 128 and the external screw thread 1 14 are engaged. When adjusting the height 124 of the known adjustable chock 100 for operational use, the installer has to keep the length of the segment 140 above a certain lower threshold, given the expected maximum magnitude of the mechanical load to be carried by the known adjustable chock 100 in operational use. For this reason, the adjustable chock known from US patent 6,068,234, mentioned above, is provided with a height indication. The height indication may, for example, comprise a scale calibration which indicates how far the first component 106 and the second component 108 have rotated with respect to each other, or a calibrated stop mark which indicates that the first component 106 and the second component 108 have reached a relative position representative of the lower threshold.

However, visibility of such a height indication may be poor under practical circumstances. The inventor therefore proposes to include a mechanical limiter in an adjustable chock to either prevent the length of the segment 140 from dropping below the lower threshold during adjustment. The mechanical limiter blocks any further increase in the height 124, or provides a tactile feedback to the installer during adjustment so as to signify to the installer that the lower threshold has been reached.

Below, and with reference to Figs. 3-14, a plurality of alternative embodiments is discussed of a mechanical limiter incorporated in an adjustable chock. That is, several alternative solutions are discussed to the problem of how to provide a lower bound to the length over which an external screw thread and an internal screw thread of engaging components overlap.

Fig.3 is a diagram of a first adjustable chock 300 according to the invention. The first adjustable chock 300 comprises a first mechanical limiter. The first mechanical limiter is formed by a first limiter part and a second limiter part. The first limiter part is formed by a first recess 302 made in an inner wall of the first through-hole 1 16. The second limiter part comprises a clip 306. The clip 306 is topologically shaped as a one-dimensional hook with a first end 308 accommodated in the first recess 302, and with a second end 310. The second end 310 travels in a ring-shaped, second recess 304 formed in a surface of the second component 108 that engages the support 104 when the height of the first adjustable chock 300 is being adjusted. The first recess 302 has a length in an axial direction 312 that determines the maximum length and the minimum length of the segment 140. While adjusting the height 124 by rotating the first component 106 and the second component 108 relative to one another, the first recess 302 travels up or down in the axial direction 312 relative to the second component 108, as well as in an angular direction so as to describe a helix conform to the helical paths of the internal screw thread 128 and the external screw thread 114. When the first recess 302 is travelling in the angular direction the clip 306 follows a circular path in a plane perpendicular to the axial direction 312, the second end 310 of the clip 306 travelling within the ring-shaped second recess 304. The travelling of the first recess 302 in the axial direction 312 is limited by a distance between the walls of the first recess 302 that are oriented substantially perpendicularly to the axial direction 312. Accordingly, the axial dimension of the first recess 302 and the axial thickness of the first end 308 of the clip 306 cooperate to restrict the lower bound of the length of the segment 140.

If so desired, the portion of the clip 306 that connects the first end 308 and the second end 310 and that runs parallel to the axial direction 312, is mounted so as to be flush with the wall of the first through-hole 116 of the first component 106, so as to provide support to the shank 118 of the bolt 120 when accommodated within the first adjustable chock 300. That is, an additional recess (not shown) is made in the wall of the first through-hole 116, shallower than the first recess 302, to accommodate the portion of the clip 306 that runs parallel to the axial direction 312.

Instead of creating the second recess 304 in the second component 108, the second recess 304 can be created by means of a separate ring (not shown) with a suitable inner diameter, larger than the diameter of the second through-hole 126 of the second component 108, and located between the second component 108 and the support 104 in a plane perpendicular to the axial direction 312. This separate ring elevates the second component 108 relative to the support 104 so as to create the second recess 304.

Fig.4 is a diagram of a second adjustable chock 400 according to the invention, being a variation on the theme of the first adjustable chock 300 of Fig.3. Instead of having the second end 310 of the clip 306 traveling within the second recess 304 of the first adjustable chock 300, the second end 310 of the clip 306 is now located underneath the support 104, i.e., at the side of the support 104 that faces away from the second adjustable chock 400. The second end 310 now may form a physically integral part of the second washer 121 that, in operational use of the second adjustable chock 400, sits between the head of the bolt 120 and the support 104, as shown in Fig.1. The first recess 302 and, optionally, the additional recess accommodating the axial part of the clip 306, are formed, for example, as axially oriented slots in the wall of the first through-hole 116. The first recess 302 and the additional recess can be formed in a variety of manners. For example, the slot or the slots can be made by a router. The router bit is positioned in an axial orientation and within the first through-hole 116. The router bit's cutting head is wider than the router bit's shaft. While spinning, the router bit is moved perpendicularly to the axial direction 312 to cut the first recess 302 into the wall of the first through-hole 116 at a distance from a surface of the first component 106 facing the support 104. The shallower, additional recess can be made with the same or another router bit to provide an open channel between the first recess 302 and the surface of the first component 106 facing the support 104. Alternatively, the first recess 302 is made by drilling into the surface of the first component 106 facing the support 104 and drilling towards the upper portion 111 of the first component 106 in one go. Then, a ring is mounted, e.g., screwed, welded or glued, against the surface of the first component 106 so as to be coaxial with the first through-hole 1 16. The ring has an inner diameter equal to the diameter of the first through-hole 1 16. The additional recess for accommodating the axial part of the clip 306 may then be formed by removing material from the ring, starting from the inner diameter and machining radially outwards, e.g., by filing, sawing or cutting, in order to create an indentation or a in order to create a cut through the entire radial width of the ring. Fig.5 is a diagram of a third adjustable chock 500 according to the invention. The third adjustable chock 500 has a second mechanical limiter with a first limiter part and a second limiter part. The first limiter part comprises a ring-shaped widening of the first through-hole 1 16 of the first component 106 so as to form a third recess 508. The second limiter part comprises a cylindrical sleeve 502 with a first flange 504 and a second flange 506. An outer diameter of the first flange 504 is smaller than an outer diameter of the second flange 506. The third recess 508 is configured for accommodating the first flange 504. The second flange 506 is positioned between the support 104 and the second component 108. When the third adjustable chock 500 is being adjusted by means of rotating the first component 106 relative to the second component 108, the position of the first flange 504 changes relative to the position of the third recess 508. The maximum height of the third adjustable chock 500 is reached when the first flange 504 hits a lower wall of the third recess 508 perpendicular to the axial direction 312. The first flange 504 is positioned within the first component 106 when the first component 106 and the second component 108 have been assembled but have not yet been positioned between the piece of machinery 102 and the support 104. Positioning the first flange 504 may require tilting the cylindrical sleeve 502 relative to the first component 106 to get the first flange 504 within the third recess 508. Alternatively, the cylindrical sleeve 502 and/or the first flange 504 are/is made of a relatively flexible material so as to enable to elastically deform the cylindrical sleeve 502 and/or the first flange 504 in order to squeeze the first flange 504 into the third recess 508. During adjustment of the third adjustable chock 500, when the bolt 120 and the nut 122 have been positioned but not yet tightened, the presence of the shank 1 18 of the bolt 120 within the cylindrical sleeve 502 will prevent the first flange 504 from escaping from the third recess 508.

Alternatively, the second limiter part initially consists of the cylindrical sleeve 502 with the second flange 506 only. After positioning the cylindrical sleeve 502 within the assembly of the first component 106 and the second component 108, the first flange 504 is formed by widening the cylindrical sleeve 502 at the end opposite the second flange 506, by means of applying a widening tool. Access to the relevant end of the cylindrical sleeve 502 is provided via the opening at the second flange 506 or via the first through-hole 1 16 entered from the concave surface 136. The widening may be made uniform along the perimeter of the cylindrical sleeve 502 or only locally. During adjustment of the third adjustable chock 500, and when the bolt 120 and the nut 122 have been positioned but not yet tightened, the presence of the shank 1 18 of the bolt 120 within the cylindrical sleeve 502 will prevent the first flange 504 from escaping from the third recess 508.

Optionally, an additional cylindrical recess (not shown) may be formed in the wall of the first through-hole 1 16 that is shallower than the third recess 508 and that serves to have an inner wall of the cylindrical sleeve 502 flush with the wall of the first through-hole 1 16.

The third recess 508 and, optionally, the additional recess accommodating the cylindrical sleeve 502, are formed as cylindrical recesses in the wall of the first through-hole 1 16 and being coaxial therewith. The third recess 508 and the additional recess can be formed in a variety of manners. For example, the recesses can be made by a router. The router bit is positioned in an axial orientation and within the first through-hole 1 16. The router bit's cutting head is wider than the router bit's shaft. While spinning, the router bit is moved perpendicularly to the axial direction 312 all around the wall of the first through-hole 1 16 to cut the third recess 508 at a distance from a surface of the first component 106 that will be facing the support 104 in operational use of the third adjustable chock 500. The shallower, additional recess can be made with the same router bit or with another router bit to provide an open channel between the third recess 508 and the aforementioned surface of the first component 106 facing the support 104 in operational use of the third adjustable chock 500. Alternatively, the third recess 508 is made by drilling the first component 106 or turning the first component 106 on a lathe. Then, a ring is mounted, e.g., screwed, welded or glued, against the aforementioned surface of the first component 106 so as to be coaxial with the first through-hole 1 16. The ring has an inner diameter equal to the diameter of the first through-hole 1 16 or somewhat larger for having the inner wall of the cylindrical sleeve 502 flush with the wall of the first recess 1 16.

Note that the cylindrical third recess 508 and, optionally, the cylindrical additional recess may also be used with the first mechanical limiter in the first adjustable chock 300 of Fig. 3 or with the second mechanical limiter in the second adjustable chock 400 of Fig.4.

Alternatively, the second flange 506 is located at the other side of the support 104, i.e., against a surface of the support 104 that faces away from the third adjustable chock 500 (not shown). In this alternative configuration, the second flange 506 may then serve as the second washer 121 between the head of the bolt 120 and the support 104 as shown in Fig. l. The hole in the support 104 to let the bolt 120 pass through may have a diameter larger than the outer diameter of the first flange 504 so as to enable to position the second limiter part, consisting of the cylindrical sleeve 502, the first flange 504 and the second flange 505, within the third adjustable chock 500 from outside. Alternatively, the cylindrical sleeve 502 and/or the first flange 504 are/is made of a relatively flexible material so as to be able to squeeze the first flange 504 from outside through the hole in the support 104 into the third recess 508. During adjustment of the third adjustable chock 500, when the bolt 120 and the nut 122 have been positioned but not yet tightened, the presence of the shank 118 of the bolt 120 within the cylindrical sleeve 502 will prevent the first flange 504 from escaping from the third recess 508. If the first flange 504 is relatively flexible, the relative flexibility will not interfere with the function of the first flange 504 to halt the travelling of the first component 106 away from the second component 108. Alternatively, the second limiter part is formed by an assembly of a first element consisting of the cylindrical sleeve 502 and the first flange 504, and a second element forming the second flange 506. The first element and the second element are jointed after the first element has been positioned within the third adjustable chock 500. The first element and the second element are jointed by, e.g., screwing, welding, brazing, gluing, etc.

Figs.6, 7, 8 and 9 are diagrams illustrating a fourth adjustable chock 600 according to the invention. The fourth adjustable chock 600 has a third mechanical limiter with a first limiter part and a second limiter part. The diagram of Fig.7 illustrates the third mechanical limiter in more detail. The first limiter part is formed by a hole 604 in the cylindrical outer wall of the lower portion 1 12 of the first component 106 that also carried the external screw thread. The second limiter part is formed by a spring-loaded catch 602 accommodated in another hole in the second component 108. The other hole in the second component 108 is conveniently made as a through- hole running in a plane substantially perpendicularly to the axial direction 312. The spring-loaded catch 602 comprises a pawl 702, a spring 704 and a plug or screw 706.

Preferably, the hole 604 and the other hole are drilled, or otherwise made, in one go, when the first component 106 and the second component 108 have been screwed together and when the length of the segment 140 has assumed the lower bound. As a result, the hole 604 in the first component 106 and the other hole in the second component 108 line up when the first component 106 and the second component 108 have assumed a particular position relative to one another that corresponds then to the minimum length of the segment 140 over which the internal screw thread 128 and the external screw thread 114 should overlap. The minimum length is determined by the expected maximum magnitude of the mechanical load on the fourth adjustable chock 600 in operational use.

If the hole 604 in the first component 106 and the other hole in the second component 108 are not aligned, the pawl 702 remains within the other hole in the second component 108. A front of the pawl 702 is slightly pressed against the external screw thread 1 14 by the spring 704, compressed between the pawl 702 and the screw 706, and the first component 106 and the second component 108 can be rotated freely relative to one another. When the hole 604 in the first component 106 and the other hole in the second component 108 are lined up, the compressed spring 704 forces the pawl 702 into the hole 604, thus blocking any further rotation of the first component 106 relative to the second component 108.

Preferably, the hole 604 in the first component 106 and the other hole that accommodates the spring-loaded catch 602 in the second component 108 are configured, at the one hand, to block, when aligned, the rotation of the first component 106 relative to the second component 108 in the direction wherein the length of the segment 140 would be reduced and, at the other hand, to allow rotation of the first component 106 relative to the second component 108 in the opposite direction. When the installer is adjusting the height of the fourth adjustable chock 600, the blocking in one direction gives a tactile signal to the installer to signify that the lower bound of the length of the segment 140 has been reached. Allowing rotation of the first component 106 relative to the second component 108 in the opposite direction enables the installer to turn back to within the safety margin of the allowable height.

The blocking of the rotation in one direction and the releasing of the blocking in the other direction of rotation can be achieved in a variety of manners. This is illustrated by the diagrams of Figs.8 and 9.

Fig.8 is a schematic diagram of the fourth adjustable chock 600 to illustrate a first example of a manner to block rotation in one direction of rotation and release the blocking in the other direction of rotation.

Fig.9 is a schematic diagram of the fourth adjustable chock 600 to illustrate a second example of a manner to block rotation in one direction of rotation and release the blocking in the other direction of rotation.

The fourth adjustable chock 600 is shown in Figs.8 and 9 as viewed along an axis of rotational symmetry 802 of the first through-hole 1 16 in a direction opposite to the axial direction 312. That is, the fourth adjustable chock 600 is viewed from the top. In the views of the diagrams of Fig.8 and 9, the first component 106 and the second component 108 are represented as if the first component 106 and the second component 108 were semi-transparent. This representation facilitates imagining the tracks of the respective locations of the hole 604 and of the spring- loaded catch 602, whose centers generally lie in different planes perpendicular to the axis of rotational symmetry 802, when the first component 106 and the second component 108 are being rotated relative to each other in order to adjust the height of the adjustable chock 600.

In the example of Fig.8, the hole 604 in the first component 106 has a direction 804 that is substantially radial, and the other hole that accommodates the spring-loaded catch 602 in the second component 108 has another direction 806, likewise substantially radial. The term "radial" as used herein refers to a direction along a line that lies in a plane perpendicular to a common axis of rotational symmetry 802 of the external screw thread 1 14 (not shown here) and of the internal screw thread 128 (not shown here) and that intersects with the common axis of rotational symmetry 802.

The fourth adjustable chock 600 is a three-dimensional object. Accordingly, if so desired, the hole 604 in the first component 106 and the other hole that accommodates the spring-loaded catch 602 in the second component 108 may be given an axial direction so that the hole 604 and the other hole assume an inclined orientation with respect to the common axis of rotational symmetry 802. Such an inclined orientation may be an advantage if the fourth adjustable chock 600 is going to be used in a moist environment. If the exposed face of the plug 706 faces downwards with respect to gravity, the chance is reduced of moisture collecting in the other hole in the second component 108 that accommodates the spring-loaded catch 602.

It is assumed here that the internal screw thread 128 and the external screw thread 1 14 are right- handed. Consider now a scenario, wherein the first component 106 is turned relative to the second component 108 in an anti -clockwise direction 808, so as to increase the height of the fourth adjustable chock 600. The pawl 702 has a cross-section in a plane perpendicular to the common axis 802 that has an asymmetric shape. As soon as the hole 604 gets aligned with the spring-loaded catch 602, the spring 704 pushes the pawl 702 partly into the hole 604. The shape of the pawl 702 and of the hole 604 are such that the particular one of the walls of the hole 604, which presses against the pawl 702 when further rotation is attempted in the anti-clockwise direction 808, exerts a force on the pawl 702 in a direction perpendicular to the radial direction of the spring-loaded catch 602. As a result, the force on the pawl 702 does not have a vector component in the radial direction 806 in order to push the pawl 702 back into the second component 108, against the pressure of the spring 704, and further rotation in the anti-clockwise direction 808 is blocked. Now, if the first component 106 is rotated in a clock-wise direction 810 when the pawl 702 is blocking rotation in the anti-clockwise direction 808, the shapes of the pawl 702 and of the hole 604 give rise to a force on the pawl 702 with a radial vector component that pushes the pawl 702 against the spring 704 back into the second component 108 so as to cancel the blocking in the clock-wise direction 810.

In the example of Fig.9, the hole 604 in the first component 106 has a direction 902 with a radial vector component 904 and a tangential vector component 906. Likewise, the other hole that accommodates the spring-loaded catch 602 in the second component 108 has another direction 908 with a radial vector component 910 and a tangential vector component 912. The expression "radial vector component" as used herein refers to a direction along a line that lies in a plane, perpendicular to the common axis of rotational symmetry 802 of the external screw thread 1 14 (not shown here) and of the internal screw thread 128 (not shown here), and that intersects with the common axis 802. The expression "tangential vector component" as used herein refers to a further direction along a line that lies in a plane perpendicular to the common axis 802 and that intersects with the common axis 802, and that runs perpendicularly to the radial vector component 910. The fourth adjustable chock 600 is a three-dimensional object. Accordingly, if so desired, the direction 902 and the other direction 908 may also have an axial vector component, i.e., a vector component that runs parallel to the common axis 802. For example, if the fourth adjustable chock 600 is going to be used in a moist environment, the direction 902 and the other direction 908 may have an axial component so as to have the exposed face of the plug 706 facing downwards with respect to gravity in order to thereby reduce the chance of moisture collecting in the other hole in the second component 108 that accommodates the spring-loaded catch 602. Again, it is assumed here that the internal screw thread 128 and the external screw thread 1 14 are right-handed. Consider now a scenario, wherein the first component 106 is turned relative to the second component 108 in the anti-clockwise direction 808, so as to increase the height of the fourth adjustable chock 600. As soon as the hole 604 gets aligned with the spring-loaded catch 602, the spring 704 pushes the pawl 702 into the hole 604. The shapes of the pawl 702 and of the hole 604 are such that the particular one of the walls of the hole 604, which presses against the pawl 702 if further rotation is attempted in the anti-clockwise direction 808, exerts a force on the pawl 702. This force has a vector component that points along the other direction 908 pushing the pawl 702 further into the hole 604. As a result, the combined force on the pawl 702 exerted by the particular wall of the hole 604 and by the spring 704, prevents the pawl 702 from escaping from the hole 604, thus blocking any further rotation in the anti -clockwise direction 808. If the first component 106 is rotated in the clock- wise direction 810 when the pawl 702 is blocking rotation in the anti-clockwise direction 808, another wall of the hole 604, opposite the aforementioned particular wall, exerts a force on the pawl 702 that has a vector component that points along the other direction 908, now pushing the pawl 702 away from the hole 604. As a result, rotating the first component 106 relative to the second component 108 in the clock- wise direction 810 assists in removing the pawl 702 from the hole 604, thus enabling rotation of the first component 106 in the clock-wise direction 810. Preferably, the pawl 702 is shaped so as to facilitate the removal of the pawl 702 from the hole 604.

Generally, with respect to the diagrams of Figs 8 and 9, the same second component 108 provided with the spring-loaded catch 604 can be used with a plurality of first components 106 that differ with regard to the location of the hole 604. Different locations of the hole 604 represent different magnitudes of the maximum height attainable by the fourth adjustable chock 600. Optionally, the hole 604 can be made as follows if the first component 106 does not have the hole 604. First, the magnitude of the maximum height of the fourth adjustable chock 600 is determined. The lower bound of the length of the segment 140 is representative of the maximum magnitude of the height. Then, the spring-loaded catch 602 is removed from the second component 108, and the first component 106 and the second component 108 are screwed together so as to have the length of the segment 140 assume the minimum length corresponding to the maximum height. Then, the hole 604 is drilled, using the other hole, which is to accommodate the spring-loaded catch 602 in the second component 108, as a guide for the drill. Consider the other hole in the second component 108. This other hole accommodates the plug or screw 706 in a first portion of the other hole, and the spring 704 and the pawl 702 in a second portion of the other hole. If the item 706 is a screw, the first portion has an internal screw thread. It may then be advisable that the first portion be given a larger diameter than the second portion in order for the drill to clear the internal screw thread of the first portion so as not to damage the internal screw thread fro the screw 706 when drilling the hole 604 in the first component 106 using the other hole as a guide. Alternatively, if the first component 106 is provided to an installer without the hole 604, and if the second component 108 is provided without the other hole to accommodate the spring-loaded catch 602, the hole 604 and the other hole can be made in one drilling operation after the first component 106 and the second component 108 have been screwed together and have been adjusted so as to have the length of the segment 140 assume the lower bound.

Fig.10 is a diagram illustrating a fifth adjustable chock 1000 of the invention, being a variation on the theme illustrated in the diagrams of Figs. 6, 7, 8 and 9 and discussed above. The fifth adjustable chock 1000 has a fourth mechanical limiter with a first limiter part and a second limiter part. The first limiter part is formed by a spring-loaded catch 1006 accommodated in the first component 106, and the second limiter part is formed by a hole 1002 in the second component 108. The spring-loaded catch 1006 is of similar configuration as the spring-loaded catch 602 discussed above. The spring-loaded catch 1006 is accommodated in another hole made in the first component 106. The hole 1002 in the second component 108 and the other hole in the first component 106 are conveniently made as a through-holes. The hole 1002 in the second component 108 may be plugged using a plug or a screw 1004. The rationales of the configurations discussed above with reference to the diagrams of Figs. 8 and 9 can be applied, mutatis mutandis, to the fifth adjustable chock 1000 of Fig.10.

Fig.1 1 is a diagram illustrating a sixth adjustable chock 1 100 of the invention. The sixth adjustable chock 1 100 has a fifth mechanical limiter with a first limiter part and a second limiter part. The first limiter part is formed by a first hooking device 1 102 attached to an outer perimeter of the upper portion 1 1 1 of the first component 106, and the second limiter part is formed by a second hooking device 1 104 attached to an outer perimeter of the second component 108. The first hooking device 1 102 has a lower end 1 106 that extends radially inwards relative to an axis of rotational symmetry of the first through-hole 1 16, and the second hooking device 1 104 has an upper end 1 108 that extends radially outwards relative to the axis of rotational symmetry of the first through-hole 1 16. The first hooking device 1 102 and the second hooking device 1 104 overlap at least partially in the axial direction 312. That is, the lower end 1106 is closer to the support 104 than the upper end 1 108 in operational use of the sixth adjustable chock 1100. The first hooking device 1102 and the second hooking device 1 104 also overlap at least partially in a radial direction 1 1 10. The lower end 1 106 travels in the axial direction 312 away from the support 104 when the first component 106 and the second component 108 are being screwed out of each other to increase the height of the sixth adjustable chock 1100. The travel of the lower end 1 106 is halted when the lower end 1106 hits the upper end 1 108.

The first hooking device 1102 and the second hooking device 1 104, together forming the sixth mechanical limiter, may also serve as a visual height indicator, e.g., of a type discussed in US patent 6,068,234, discussed above. An exposed radially outwards facing surface of the second hooking device 1104 is then marked so as to provide a frame of reference to the installer in order to be able to read the position of the lower end 1106 as a representative of the height of the sixth adjustable chock 1 100. The first hooking device 1102 and the second hooking device 1104, together forming the fifth mechanical limiter, may also serve as a protection against foreign matter coming from outside and contaminating the internal screw thread 1 14 and the outer screw thread 128. For this protection to work, each of the first hooking device 1 102 and the second hooking device 1 104 is ring-shaped so as to fully enclose an outer perimeter of the upper portion 111 of the first component 106 and an outer perimeter of the second component 108, respectively. A seal 1112 may be provided between the first hooking device 1 102 and the second hooking device 1 104. The first hooking device 1102 and the second hooking device 1204 need not each be ring-shaped. For example, one of the first hooking device 1102 and the second hooking device 1104 is ring- shaped and the other one of the first hooking device 1102 and the second hooking device 1104 is merely a strip having a substantive dimension only in the axial direction 312. As another example, the first hooking device 1102 is formed as a first such a strip and the second hooking device 1 104 is formed as a second such a strip. The first strip and the second strip are positioned at the sixth adjustable chock 1100 in such a way as to be aligned in the axial direction 312 and having the lower end 1106 and the upper end 1 108 hitting each other when the maximum height of the sixth adjustable chock 1100 has been attained.

Instead of having a configuration wherein the lower end 1 106 extends radially inwards and the upper end 1108 extends radially outwards, as shown in the diagram of Fig.11, the lower end 1106 may be configured to extend radially outwards and the upper end 1 108 may be configured to extend radially inwards. This may be a design choice, depending on, e.g., the orientation of the sixth adjustable chock 1100 with respect to gravity. For example, if each respective one of the first hooking device 1102 and the second hooking device 1104 is formed as a respective ring, the respective rings are mounted so as to have the upper one of the rings (with respect to gravity) overlap the lower one of the rings (with respect to gravity) in order to reduce foreign matter being forced between the rings under control of gravity.

Figs.12, 13 and 14 are diagrams illustrating a seventh adjustable chock 1200 of the invention. A major difference between the seventh adjustable chock 1200 of Fig.12 and the known adjustable chock 100 of Fig.l is that the rigid first component 106 of the known adjustable chock 100 has been replaced by an assembly of a threaded hollow rod 1202 and a fourth component 1204.

Fig.13 is a diagram of the seventh adjustable chock 1200, wherein a left half 1302 illustrates the left half of the view of the seventh adjustable chock 1200 as illustrated in Fig.13, and wherein the right half 1304 illustrates a cross-section of the seventh adjustable chock 1200 in a plane that contains an axis 1306 of rotational symmetry of the first through-hole 1 16 of the threaded hollow rod 1202. The threaded hollow rod 1202 has the external screw thread 1 14. The fourth component 1204 has a fourth through-hole 1308, whose inner wall has been provided with an internal screw thread 1310 matching the external screw thread 1 14 of the threaded hollow rod 1202 for making a screw coupling between the threaded hollow rod 1202 and the fourth component 1204. The fourth component 1204 plays the role of the upper portion 1 1 1 of the rigid first component 106.

As a result of replacing the rigid first component 106 by the assembly of the threaded hollow rod 1202 and the fourth component 1204, the height 124 of the seventh adjustable chock 1200 can be adjusted by means of rotating the second component 108 and the threaded hollow rod 1202 relative to one another, as well as by means of rotating the fourth component 1204 and the threaded hollow rod 1202 relative to one another. Accordingly, the seventh adjustable chock 1200 has two ways of adjusting the height 124 that can be used independently of one another.

In the example shown in the diagram of Fig.12, the second component 108, the third component 1 10 and the fourth component 1204 have a respective rotationally symmetrical outer surface facing in the radial direction away from the axis 1306 of rotational symmetry of the first through- hole 1 16. Each respective one of the rotationally symmetrical outer surface of the second component 108, the rotationally symmetrical outer surface of the threaded hollow rod 1202 and the rotationally symmetrical outer surface of the fourth component 1204 is provided with one or more respective holes, e.g., a first hole 1206 in the second component 108, a second hole 1208 in the threaded hollow rod 1202 and a third hole 1210 in the fourth component 1204. These holes are configured for accommodating a tommy bar in order to be able to apply a torque to the relevant one of the second component 108, the threaded hollow rod 1202 and the fourth component 1204.

Owing to the modular configuration of the seventh adjustable chock 1200, the same fourth component 1204 and the same second component 108 can be combined with externally threaded hollow rods 1202 of different lengths so as to create different seventh adjustable chocks 1200 suitable for different ranges of height. Externally threaded hollow rods of different lengths can be simply made by cutting off pieces of different lengths of a threaded hollow bar. A threaded hollow bar is a relatively inexpensive device and cutting is a relatively inexpensive machining operation. In addition, part of the adjustability of the seventh adjustable chock 1200 can be delegated to cutting a piece of pre-determined, accurate length off the threaded hollow bar. This enables to control in advance the length, over which the threaded hollow rod 1202 engages with the second component 108 in operational use of the seventh adjustable chock 1200, and the length, over which the threaded hollow rod 1202 engages with the fourth component 1204 in operational use of the seventh adjustable chock 1200 of the invention. A greater length of engagement results in stronger mechanical support.

The mechanical limiters discussed above with reference to the diagrams of Figs.3-1 1 can be used to control the lower bound of the length over which the internal screw thread 128 of the second component 108 engages with the external screw thread 1 14 of the threaded hollow rod 1202. In order to control the lower bound of the length over which the internal screw thread 1310 of the fourth component 1204 engages with the external screw thread 1 14 of the threaded hollow rod 1202, a configuration of one or more of the mechanical limiters is preferably used as discussed above with reference to the fourth adjustable chock 600 of diagrams of Figs.6, 7, 8, 9 and 10.

Fig.14 is a diagram of a cross-section of an example embodiment of the seventh adjustable chock 1200 in a plane that contains the axis 1306 of rotational symmetry of the first through-hole 1 16 of the threaded hollow rod 1202. A first spring-loaded catch 1402 is accommodated in the second component 108, and a second spring-loaded catch 1404 is accommodated in the fourth component 1204. Each of the first spring-loaded catch 1402 and the second spring-loaded catch 1404 is of a configuration of the spring loaded catch 602 as discussed above with reference to the diagrams of Figs.6, 7, 8 and 9 illustrating the fourth adjustable chock 600. The threaded hollow rod 1202 is provided with a first hole 1406 for cooperation with the first spring-loaded catch 1502, and with a second hole 1408 for cooperation with the second spring-loaded catch 1404. In the example embodiment of Fig.14, the pawl of the second spring-loaded catch 1404 is shown as occupying the second hole 1408 so as to block further rotation of the threaded hollow rod 1202 relative to the fourth component 1204 in a direction wherein an overlap between the external screw thread 114 and the internal screw thread 1310 decreases. That is, a minimum length 1410 of the overlap between the external screw thread 114 and the internal screw thread 1310 has been reached.

As has been discussed above with reference to the diagrams of Figs. 8 and 9, the blocking of the relative rotation of the first component 106 and the second component 108 in one direction and the releasing of the blocking in the other direction of relative rotation can be achieved in a variety of manners. Similar considerations apply to the blocking of the relative rotation of the first component 106 and the fourth component 1204 in one direction and the releasing of the blocking in the other direction of relative rotation.

Fig. 15 is a schematic diagram to illustrate a third example of a manner to block the relative rotation in one direction and release the blocking in the other direction of relative rotation, illustrated with reference to the relative rotation of the first component 106 and the second component 108.

The diagram of Fig.15 differs from the diagram of Fig.9, discussed above, in that the hole 604 in the first component 106 has a substantially radial direction. That is, the hole 604 is oriented along a line 1502 that intersects with the common axis of rotational symmetry 802 of the external screw thread 114 (not shown here) of the first component 106 and of the internal screw thread 128 (not shown here) of the second component 108. The spring-loaded catch 602 is oriented so as to assume the other direction 908 with the radial vector component 910 and the tangential vector component 912. Rotating the first component 106 relative to the second component 108 in the anti-clockwise direction 808 eventually causes the pawl 702 of the spring-loaded catch 602 to enter the hole 604 to engage. If the pawl 702 has entered the hole 604, further rotation of the first component 106 relative to the second component 108 is blocked in the anti-clockwise direction 808, as the walls of the hole 604 are exerting a force on the pawl 702 that has a vector component pointing along the line 1502 in the radially inwards direction, i.e., a vector component pointing towards the common axis of rotational symmetry 802 of the external screw thread 1 14 and of the internal screw thread 128. Accordingly, the pawl 702 is forced to remain within the hole 604 and obstructs further relative rotation in the anti-clockwise direction 808. If an attempt is made to rotate the first component 106 relative to the second component 108 in the clockwise direction 810 while the pawl 702 is engaged with the hole 604, the walls of the hole 604 are exerting a force on the pawl 702 that has another vector component in the radially outwards direction, i.e., another vector component pointing along the line 1502 and away from the common axis of rotational symmetry 802 of the external screw thread 1 14 and of the internal screw thread 128. Accordingly, the pawl 702 is forced out of the hole 604 so as to allow further relative rotation in the clockwise direction 810.

A configuration of a mechanical limiter with a radially oriented hole 604 can therefore be used with a spring-loaded catch 602 oriented in a radial direction as well, as shown in the diagram of Fig.8, or oriented so as to have a tangential directional vector component as well as a radial directional vector component, as shown in the diagram of Fig.15. Note that in the configuration shown in the diagram of Fig.15, the pawl 702 can have a simple shape, inexpensive to manufacture, and that the radially oriented hole 604 can readily be drilled at the time of installing the adjustable chock 600. The drilling of a radial hole is easier than the drilling of a hole whose orientation is to have a radial direction as a well as a tangential direction.

Fig.16 is a diagram illustrating a particular spring-loaded catch 1600 that can be considered a particular implementation of the spring-loaded catch 602 of Figs.6, 7, 8, 9, 10 and 15, of the first spring-loaded catch 1402 of Fig.14, or of the second spring-loaded catch 1404 of Fig.14. The particular spring-loaded catch 1600 comprises a pawl 702, a spring 704 and a plug or screw 706. The particular spring-loaded catch 1600 is accommodated in a first hole 1602 made in a relevant one of the first component 106, the second component 108 and the fourth component 1204, as discussed above. In the example shown in Fig.16, the particular spring-loaded catch 1600 is accommodated at the second component 108. The pawl 702 of the particular spring-loaded catch 1600 is configured for engaging with a second hole 1604 made in another relevant one of the first component 106, the second component 108 and the fourth component 1204, as discussed above. In the example of Fig.16, the pawl 702 is configured to engage with the second hole 1604 in the first component 106.

The first hole 1602 has a wide portion 1606 and a narrow portion 1608. The wide portion 1606 extends to an outer perimeter of the second component 108, and the narrow portion 1608 extends into the internal screw thread 128 at the wall of the inner through-hole 126 of the second component 108. The pawl 702 of the particular spring-loaded catch 1600 has a collar 1610 that faces the spring 704 and that is located within the wide portion 1606 of the first hole 1602. The collar 1610 also has an engaging end 1612 that is located within the narrow portion 1608 of the first hole 1602. The engaging end 1612 is configured for engaging with the second hole 1604 when the first hole 1602 and the second hole 1604 are aligned, so as to block a further relative movement of the first component 106 and the second component 108, as has been explained above. Owing to the configurations of the first hole 1602 and of the pawl 702, the pawl 702 of the particular spring-loaded catch 1600 cannot inadvertently drop out of the first hole 1602 when the engaging end 1612 of the pawl 702 does not rest against the external screw thread 1 14, e.g., when the first component 106 and the second component 108 have not yet been screwed together. The spring 704 presses the collar 1610 of the pawl 702 in the direction of the narrow portion 1608, but since the collar 1610 has an outer diameter that is larger than an inner diameter of the narrow portion 1608, the collar 1610 is too large to enter the narrow portion 1608 and, as a result, is to remain within the wide portion 1606, which facilitates handling the second component 108 and assembling the first component 106 and the second component 108 through the screwed connection.

Claims

A system configured for use as an adjustable chock (300; 400; 500; 600; 1000; 1100; 1200) for connecting a piece of machinery (102) to a support (104), wherein:

the adjustable chock comprises:

a first component (106; 1302) having an external screw thread (1 14);

a second component (108) having an internal screw thread (128) configured for engaging with the external screw thread of the first component;

the external screw thread and the internal screw thread engage in operational use of the adjustable chock over a distance (140), determined in an axial direction parallel to a common axis of the internal screw thread and the external screw thread;

the distance is adjustable by means of rotating the first component and the second component relative to one another while the internal screw thread and the external screw thread remain engaged; and

the adjustable chock comprises a mechanical limiter (302, 306, 308, 310; 502, 504, 506, 508; 602, 604; 1002, 1006; 1102, 1104; 1402, 1404, 1406, 1408) configured to mechanically limit a lower bound of the distance to a pre-set value while the internal screw thread and the external screw thread remain engaged.

The system of claim 1 , wherein:

the mechanical limiter comprises a first limiter part (306; 502) and a second limiter part (302; 508);

the first limiter part is configured for being stationary in the axial direction with respect to the first component;

the second limiter part is configured for being stationary in the axial direction with respect to the second component;

the first component has a first through-hole (116) coaxial with the external screw thread; the first limiter part comprises a recess (302; 508) in a wall of the first through-hole;

the second limiter part has a portion (308; 504) extending into the recess in operational use of the adjustable chock;

the pre-set value of the lower bound is determined by a position of the recess in the wall in the axial direction and by a length of the recess in the axial direction. The system of claim 1, wherein:

the first component comprises an upper portion (111) and a lower portion (112);

the lower portion accommodates the external screw thread;

the mechanical limiter comprises a first limiter part and a second limiter part;

the first limiter part comprises a first hooking device (1102) attached to a first outer perimeter of the upper portion;

the second limiter part comprises a second hooking device (1 104) attached to a second outer perimeter of the second component;

the pre-set value of the lower bound is reached when the first hooking device and the second hooking device hook into each other.

The system of claim 1, wherein:

the first limiter part is accommodated at one of the first component and the second component;

the second limiter part is accommodated at the other one of the first component and the second component;

the first limiter part comprises a spring-loaded catch (602; 1006; 1402; 1600);

the second limiter part comprises a hole (604; 1002; 1406; 1604) configured for engaging with the spring-loaded catch when the spring-loaded catch and the hole are aligned;

the pre-set value of the lower bound is reached when the spring-loaded catch and the hole engage.

The system of claim 4, wherein the spring-loaded catch is configured for operating in a direction with a vector component (912) that is tangential to a movement of the first component and the second component relative to one another when the first component and the second component are being rotated relative to one another with the external screw thread and the internal screw thread engaged.

The system of claim 1, 2, 3, 4, or 5, wherein:

the adjustable chock comprises a fourth component (1204) with a further internal screw thread (1310) configured for engaging with the external screw thread of the first component; in operational use of the adjustable chock, the external screw thread and the further internal screw thread engage over a further distance (1410), determined in an axial direction parallel to a common axis of the further internal screw thread and the external screw thread;

the further distance is adjustable by means of rotating the first component and the fourth component relative to one another while the further internal screw thread and the external screw thread remain engaged;

the adjustable chock comprises a further mechanical limiter (1404, 1408) configured to mechanically limit a further lower bound of the further distance to a further pre-set value while the further internal screw thread and the external screw thread remain engaged.

7. A further system comprising a piece of machinery (102), a support (104) and an adjustable chock (300; 400; 500; 600; 1000; 1 100; 1200) connecting the piece of machinery to the support, wherein:

the adjustable chock comprises:

a first component (106; 1202) having an external screw thread (1 14);

the distance is adjustable by means of rotating the first component and the second component relative to one another while the internal screw thread and the external screw thread remain engaged;

the adjustable chock comprises a mechanical limiter (302, 306, 308, 310; 502, 504, 506, 508; 602, 604; 1002, 1006; 1 102; 1 104; 1402; 1404; 1406; 1408) configured to mechanically limit a lower bound of the distance to a pre-set value while the internal screw thread and the external screw thread remain engaged.