GB2591129A

GB2591129A - Jack assembly for use in propping systems

Info

Publication number: GB2591129A
Application number: GB2000720.9A
Authority: GB
Inventors: Douglas Hesketh Stephen; John Horrocks Mark; Phan Nigel; Mark Carter Christopher
Original assignee: MGF TRENCH CONSTRUCTION SYSTEMS Ltd
Current assignee: MGF TRENCH CONSTRUCTION SYSTEMS Ltd
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2021-07-21
Anticipated expiration: 2040-01-17
Also published as: GB2591129B; GB202000720D0

Abstract

A jack assembly 100 for varying or adjusting the relative positions of a first component, such as a prop (P1, 2 fig.1a), and a second component, such a foot (F1, 2 fig.1b) or end plate (EL2, EU2 fig.1b). The jacking system includes a base 120 attachable to the first component wherein the base includes a housing 124 having a longitudinal channel A extending therethrough and defining an axis of the assembly. An externally screw-threaded rod or bar 160 is attachable at or adjacent at one of its ends 164 to the second component and a collar 140, mounted within the channel A, is internally screw-threaded so as to be able to screwingly receive a portion 162 of the rod or bar 160 upon rotation about the axis. The collar is freely rotatable about the axis yet is constrained, perhaps by an annular step 147, so as not to be moveable relative to the base portion 120 along the axis.

Description

JACK ASSEMBLY FOR USE IN PROPPING SYSTEMS

TECHNICAL FIELD

This invention relates to a jack assembly for use in a propping system. More particularly, though not exclusively, the invention relates to a novel jack assembly which is employable in conjunction with one or more other components of an overall propping system, especially a prop or prop section. Such a propping system, and the new jack assembly which forms a part thereof, are usable in a variety of building, civil engineering and industrial scenarios where structural support apparatus is required. The invention further relates to a propping system including one or more jacks being of the new jack assembly of the invention, and to a method of jacking a prop or prop section of a propping system using the new jack assembly.

BACKGROUND OF THE INVENTION AND PRIOR ART

In many building, civil engineering and industrial operations some kind of structural support system or equipment is often required for temporarily supporting part or all of the structure being constructed or worked on in a stable and safe manner. Such structural support systems typically include props, which are usually designed to be of adjustable lengths, which are used to securely brace or support the relevant structure (or part thereof) while the necessary work or construction is carried out. Typical applications of such propping systems include for example the supporting of buildings or parts of buildings during construction, refurbishment, repair, reconstruction or demolition, as well as various civil engineering scenarios such as in the construction or repair of roads, bridges and railways.

In such propping systems it is often required that jacks are available and deployed for the purposes of supporting one or more of the props at their foot ends at appropriate but variable heights above a ground or floor surface, and/or supporting various ones of the props at either or each of their longitudinal ends so as to vary or adjust the effective overall longitudinal length of a given prop to a specific desired distance. Such length-adjustment/variation capability is often important in propping systems where modular prop sections of different but fixed longitudinal lengths are available but may be employed in various linear or other geometric combinations to form one or more desired props or prop arrangements of a particular desired overall size or configuration.

Known jacks generally rely on some kind of rotatable structure -generally some kind of screw-threaded rod -for providing the length-adjustable capability. Some known jacks comprise a longitudinally-oriented screw-threaded rod which is fixedly anchored at one end and carries in threaded engagement therewith a rotatable part of the component whose longitudinal position is required to be variable/adjustable. In the use of such jacks the rotatable part of the component whose longitudinal position is to be varied/adjusted is simply rotated (either manually or by use of a tool) in the appropriate rotational direction to either lengthen or shorten the effective distance between the engaged component and the anchored end of the rod.

In some other known jacks a threaded rod, free at both ends, is employed, but it is split into two halves each with a screw-thread of opposite orientation to the other, so that one half of the rod has a left-handed thread and the other half has a right-handed thread. This allows each half of the rod to engage part of a respective one of two components whose mutual longitudinal spacing is to be variable/adjustable by virtue of both components being simultaneously longitudinally moveable but in opposite directions -i.e. either simultaneously mutually towards or away from one another -upon rotation of the entire rod in an appropriate one of its rotational directions. This form of mutual spacing-adjustable jack may be useful in instances where a pair of components need to be mutually longitudinally moveable relative to each other and both ends of such a dual-threaded rod are free to rotate.

However, the above known types of jack assembly are unsuitable for some practical applications, in particular in propping systems in which at least one of, and perhaps even both of, a pair of components whose longitudinal position(s) is/are to be variable/adjustable is/are itself/themselves not free to rotate during a jacking procedure or do not comprise a rotatable part able to rotate relative to the remainder of the component. Such pairs of components may for example be constituted by two mutually end-to-end interconnectable props or prop sections, or a prop/prop section and one or more other components of the propping system, such as a support beam, needle, ground-engaging foot plate, or other non-rotatable supporting element or arrangement. Such scenarios, in which conventional jacks/jack assemblies have been found to be unsuitable, may often be encountered in more modern propping systems based on the use of modular props/prop sections.

It is therefore a primary object of the present invention to ameliorate or at least partially solve at least some of the shortcomings of known jacks and jack assemblies, especially those hitherto available for use in propping systems, and to provide a new jack assembly which has greater utility and mrider-reaching practical applications, especially in propping systems, and which is simple and easy to use and operate, without being over-engineered.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect the present invention provides a jack assembly for use in a propping system for varying or adjusting the relative positions of at least first and second components of the propping system relative to each other, wherein the jack assembly comprises: a base portion attachable to the first component of the propping system, wherein the base portion includes a housing portion having a longitudinal channel extending therethrough, the said longitudinal channel defining an axis of the assembly; an externally screw-threaded rod or bar attachable at or adjacent at least one of its ends to the second component of the propping system, and a collar mounted within the channel of the housing portion of the base portion, wherein the collar is internally screw-threaded so as to be able to screwingly receive therein a portion of the rod or bar upon rotation thereof about the said axis; wherein the collar is mounted within the channel of the housing portion of the base portion such as to be freely rotatable therewithin about the said axis yet is constrained so as to be not substantially moveable relative to the base portion in a direction along the said axis.

In another aspect of the present invention there is provided a base assembly for forming a jack assembly for use in a propping system for varying or adjusting the relative positions of at least first and second components of the propping system relative to each other, wherein the base assembly comprises: a base portion attachable to the first component of the propping system, wherein the base portion includes a housing portion having a longitudinal channel extending therethrough, the said longitudinal channel defining an axis of the assembly; and a collar mounted within the channel of the housing portion of the base portion, wherein the collar is internally screw-threaded for screvvingly receiving therein a portion of a rod or bar attached at or adjacent at least one of its ends to the second component of the propping system and upon rotation of the rod or bar about the said axis; wherein the collar is mounted within the channel of the housing portion of the base portion such as to be freely rotatable therewithin about the said axis yet is constrained so as to be not substantially moveable relative to the base portion in a direction along the said axis.

In yet another aspect of the present invention there is provided a propping system, the propping system comprising: at least one first component and at least one second component of the propping system, the relative positions of the first and second components being variable or adjustable relative to each other; and at least one jack assembly according to the first aspect of the invention or any embodiment thereof, for effecting the said variation or adjustment of the relative positions of the first and second components relative to each other upon rotation of the rod or bar screvvingly received in the collar mounted within the housing portion of the base portion of the jack assembly.

In yet another aspect of the present invention there is provided a method of varying or adjusting the relative positions of first and second components of a propping system relative to each other, the method comprising: providing at least one jack assembly according to the first aspect of the invention or any embodiment thereof; attaching the base portion of the jack assembly to the first component of the propping system and attaching the rod or bar, at or adjacent at least one of its ends, to the second component of the propping system; rotating the rod or bar, once screwingly received in the collar mounted within the channel of the housing portion of the base portion of the jack assembly, so as to effect the said variation or adjustment of the relative positions of the first and second components relative to each other.

In some embodiments of the invention in its various aspects, the collar may comprise a main tubular (especially cylindrical) portion provided with the said internal screw-thread and for screwingly receiving therein the said portion of the rod or bar, and a handle portion extending from the tubular portion for use in effecting the said free rotation of the collar in its axially constrained mounting in the housing portion. Thus, the collar is able to freely rotate in either of its rotational directions relative to the rod or bar, and in doing so the two parts move relative to each other in a direction along a longitudinal axis of the rod or bar, by virtue of their inter-engaged screw-threads.

In some such embodiments the handle portion may extend transversely outwardly from, especially perpendicularly relative to the axial direction of, the tubular portion. In particular, the handle portion may so extend from a location at or adjacent one axial end of the tubular portion.

In some embodiments the handle portion may comprise one or more, especially a plurality of (e.g. 3), arms, each arm being manipulatable, e.g. manually or by use of a tool, for effecting the said free rotation of the collar in its axially constrained mounting in the housing portion. Where such a plurality of arms are provided, they may be symmetrically or equi-angularly disposed around the tubular portion of the collar.

In practising embodiments of the present invention, in order to effect the desired axial relative position variation or adjustment of the first and second propping components upon the rotation of the collar within its axially constrained mounting in the housing portion, it may be preferred that the attachment of the first propping component to the base portion is such that the first propping component and the base portion are substantially axially non-rotatable relative to each other, and further that the attachment of the second propping component to the rod or bar is such that the second propping component and the rod or bar are substantially axially non-rotatable relative to each other. In this manner, the respective pairs of component parts that are so attached to each other may be constrained so as to be substantially axially non-rotatable relative to each other within each pair, thereby enabling the rotation of the collar, with the rod or bar screwingly received therein, to effect the axial movement of the rod or bar relative to (i.e. through) the housing portion of the base portion and thus to effect the relative axial movement of the first and second propping components either axially towards or away from one another.

In accordance with the invention in its various aspects, the collar is mounted within the housing portion of the base portion (especially, more strictly, within the channel of the base portion) such as to be freely rotatable therewithin, especially upon operation of its handle portion (in embodiments where such is provided), about the said axis yet is constrained so as to be not substantially moveable relative to the base portion in a direction along the said axis. This primary feature of the invention thus enables the collar to be rotated within the channel in the housing in either of its rotatable directions, but owing to the axial constraining nature of its mounting in the base portion it substantially cannot move relative to the base portion in that axial direction upon that rotation, so upon its rotation the rod or bar itself moves in that axial direction relative to the base portion, thereby carrying with it the second propping component attached thereto which thus also moves in that axial direction relative to the base portion.

In some embodiment forms of the jack assembly of the invention, in order to (at least partially) form or contribute to the axially constrained mounting of the collar in the housing portion of the base portion (i.e. within the channel therein), the collar may comprise the above-defined main tubular (especially cylindrical) portion provided with the said internal screw-thread, and the tubular portion may include an externally radially enlarged or radially reduced portion which engages with a corresponding internally radially reduced or radially enlarged (respectively) portion of the housing portion. Such respective externally/internally radially enlarged or radially reduced portions of each of the collar tubular portion and the housing portion may be defined by, or delimited from the remainder of those respective parts by, a respective step or stepped portion, especially a respective annular step, formed in and between the relevant walls of those respective components. The relative configurations of the respective steps or stepped portions may be such that they constrain the collar so as to be not substantially axially retractable from the housing portion in a first axial direction.

In some such embodiments the respective externally/internally radially enlarged or radially reduced portions of each of the collar tubular portion and the housing portion may be relatively dimensioned such that there is a small gap, especially a cylindrical gap (e.g. of a width of from about 0.1 or 0.2 or 0.3 or 0.5 mm up to about 0.6 or 0.8 or 1 or 1.5 or 2 mm) between them, in order that the two parts (i.e. the collar tubular portion and the housing portion) are able to move freely past one another as the collar tubular portion rotates vvithin the housing portion. The said gap may for example be filled with a suitable lubricant, e.g. a grease or oil, in order to facilitate that relative rotatable movement between the two parts.

In some such embodiments, in order to fully assure the overall constrained nature of the mounting of the collar in the housing portion of the base portion (i.e. ithin the channel therein), the base portion may include an apertured base plate attached (e.g. by welding) to an axial end of the housing portion distal or spaced from the respective steps or stepped portions of the collar tubular portion and the housing portion, and which apertured base plate partially occludes the mouth of the channel in the housing portion so as to prevent the collar being retractable therefrom via that end of the channel, i.e. so as to constrain the collar so as to be not substantially axially retractable from the housing portion in a second axial direction, that second axial direction being opposite to the above-mentioned first axial direction.

Thus, in other words, in some embodiments, in order to provide the axially constrained mounting of the collar in the housing portion of the base portion (i.e. ithin the channel therein), the tubular portion of the collar may comprise may further include an engagement portion of enlarged external radius or diameter compared mtith the external radius/diameter of the main part/body of the tubular portion which is contained or housed within a containment portion of the housing portion of the base portion, which containment portion takes the form of a cylindrical portion of the housing portion of a correspondingly increased internal radius or diameter compared with the internal radius/diameter of the remainder of the housing portion, especially compared with the internal radius/diameter of the remainder of the housing portion on both axial sides of the containment portion.

In some practical embodiments, in the form of the jack assembly provided ready for use, the externally threaded rod or bar may be received in the collar so as to be engaged with, and internally of, the collar, but still screwingly rotatable relative thereto. In some such forms of the jack assembly provided ready for use, the portion of the rod or bar that is actually engaged with the collar may be a region thereof in or adjacent or near a central portion thereof or intermediate the respective end portions thereof -up to which region the rod or bar has been screvvingly inserted axially into the collar so that the assembly is ready for use. Once in that condition, it may be only then that the respective first and second propping components may be respectively attached to the base portion and the rod or bar of the assembly.

In many practical embodiments the externally threaded rod or bar to which is attachable the second propping component may be an elongate cylindrical rod or bar, e.g. of a suitably hard and strong metal or metal alloy (e.g. a steel), which comprises a central portion which is provided with the said external screw thread and at least one end portion which includes attachment means for attachment of that end portion of the rod or bar to the second propping component. That attachment means may comprise for example a through-hole or socket, bracket, clip or other anchoring element or feature, optionally to which may be attached a secondary anchoring element, e.g. a bolt, nut or screw, which engages the second propping component and so anchors it to the rod or bar.

In some practical embodiments the base portion may be attached to the first propping component by its own respective attachment means, such as one or more, especially a plurality of, bolts, nuts, screws or other anchoring elements. Suitably, such anchoring elements may cooperate with appropriately configured and positioned secondary anchoring element(s) located on the relevant first propping component, especially on or adjacent an end portion thereof.

In many practical embodiments of the jack assembly of the invention as it may be applied to a jacking procedure or capability in a propping system, the first and second propping components may be selected from any components of a propping system which are required to be moveable relative to each other, especially in terms of being positionable relative to each other at a spacing distance which is variable or adjustable.

In many embodiments one of the first and second propping components may be a prop or a prop section, such as one of a group or set or kit of different length prop sections which are designed for use in a modular fashion. Such props or prop sections may for example generally comprise a pair of back-to-back generally C-shaped channel sections, especially those known in the art generally as "sigma sections", which are spaced apart and bounded at their longitudinal ends and united securely together by a pair of transverse centrally-apertured end plates, optionally (if desired or appropriate) with a suitable number of internal bracing members and/or external stiffener elements located and attached to the respective channels sections at various selected points longitudinally therealong. In such prop sections either one of the respective end plates may provide a suitable attachment site at which such a prop section may be attached to the base portion of the jack assembly of embodiments of the present invention. (Of course, other forms of prop or prop section may be employed instead, in other embodiments.) Also in many embodiments, the other of the first and second propping components may be either another prop or prop section -in which case the jack assembly may be used to interconnect in a length-adjustable or length-variable manner such a pair of prop sections -or some other component of the propping system, such as a beam, needle, foot plate ground support plate, or other non-rotatable supporting element or arrangement forming part of the overall propping system.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. Thus, any one or more features referred to or described with reference to one particular embodiment should be construed as being applicable to any or all embodiments, unless expressly stated otherwise or such features are incompatible.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention in its various aspects will now be described in detail, by way of non-limiting example only, with reference to the accompanying drawings, in which FIGURES 1(a), 1(b), 1(c), 1(d), 1(e) and 1(f) are various views illustrating various type of propping systems in deployment which incorporate various prop sections and associated jacks for adjusting their heights in relation to what they are supporting; FIGURE 2 shows in general illustrative terms some examples of the kinds of components of an overall propping system such as those being deployed as shown in FIGS. 1(a)-(f), which components include some examples of jack assemblies as may be used in the propping systems of FIG. 1; FIGURE 3 is a perspective view of a jack assembly according to one embodiment of the present invention; FIGURE 4 is a side elevational view of the jack assembly of FIG. 3; FIGURE 5 is a top plan view of the jack assembly of FIG. 3; FIGURE 6 is a perspective view of the combined base portion and mounted collar alone of the jack assembly of FIG. 3; FIGURE 7 is a side elevational view of the combined base portion and mounted collar alone of FIG. 6; FIGURE 8 is a cross-sectional view on line A-A of FIG. 5, but showing the combined base portion and mounted collar alone of the assembly; FIGURE 9 is an enlarged detail cross-sectional view of the region indicated as "B" in FIG. 8; FIGURE 10 is a perspective view of the threaded rod or bar used to form the jack assembly of FIGS. 3, 4 and 5.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring firstly to FIGS. 1(a) -1(f), these FIGS. illustrate some representative schematic examples of various types of propping system to which various embodiments of the present invention may be applied, and in particular which include the deployment and use of various embodiments of prop section according to the invention.

FIGS. 1(a), 1(b) and 1(c) show, respectively, perspective, end-on and close-up-partial views of an example of a propping and needling system, in which a series of uniformly spaced-apart vertical prop section P1 according to one embodiment of the invention are used to support a building structure B via respective ones of a series of horizontal needles (i.e. short I-beams) N extending beneath the building structure. Each vertical prop section P1 is braced so as to help maintain its vertical supporting orientation by respective ones of a series of obliquely inclined prop sections P2 according to another (or the same) embodiment of the invention. Additional diagonally and/or horizontally mounted support/bracing poles S are also employed to provide further stabilising support to the overall propping/needling system structure. Each of the prop sections P1 and P2 is supported on the ground via a respective foot plate Fl, F2 which is carried on the end of a length-adjustable rod or jack assembly J1, J2 which is attached to the respective prop section P1, P2 via the latter's lower end plate ELI, EL2. The prop sections P1, P2 of each pair are interconnected via a rod connector (which may itself be length-adjustable, if desired or appropriate) which is anchored to the respective inclined prop section P2 of each pair via the latter's opposite (upper) end plate EU2.

FIG. 1(d) is a perspective view of an example of a façade retention system, in which a pair of propping towers T formed from interconnected plural prop sections P each according to one or more embodiments of the invention are used to support and retain in an upright condition the façade of a building B, e.g. during its repair, reconstruction or demolition.

FIGS. 1(e) and 1(f) show, respectively, perspective and close-up-partial-underside views of a bridge propping and jacking system, in which a pair of propping towers T formed from interconnected plural prop sections P each according to one or more embodiments of the invention are used to support and jack up a bridge BR. Each of the main vertical prop sections P is made up of a series of individual prop sections interconnected end-to-end directly to one another, and is supported on the ground via a respective foot plate F which is carried on the end of a length-adjustable rod or jack assembly J which is attached to the respective lowermost vertical prop section P via the latter's lower end plate EL. As shown in FIG. 1(f), the upper end of each propping tower T supports the bridge structure BR via support beams M and additional (e.g. hydraulic) jacks J H. It is to be understood that the propping systems illustrated in FIGS. 1(a) -1(f) are just a selection of some illustrative representative examples of overall propping systems which may incorporate prop sections in accordance with embodiments of the present invention, and many other different propping arrangements may be designed for use in any particular building, civil engineering or industrial scenario for which propping is needed.

FIG. 2 shows in general illustrative terms some examples of the kinds of components of an overall propping system which may be used in the deployment thereof, including those example systems illustrated in FIGS. 1(a) -1(f). These components include, for instance, one or more jacks or jack assemblies J1, J2 (which may be of different types), foot plate supports F, support legs S, tension braces T, and a selection of props or prop sections P. The jacks/jack assemblies shown as J1 are according to an embodiment of the present invention.

Turning to FIGS. 3 to 9, these FIGS. show an embodiment of a jack assembly according to the present invention which may be used in various ways in a propping system such as those example ones illustrated in FIGS. 1(a) -(f), or even others. Such a jack assembly may be used to join or unite any two components of the propping system which are required to be a to be moveable relative to each other in terms of being positionable relative to each other at a spacing distance which is variable or adjustable. Such components may typically for instance be a pair of props or prop sections which are required to be interconnectable end-to-end in a length-(or spacing-)variable or length-(or spacing-)adjustable manner, or alternatively they may perhaps comprise one such prop or prop section and a beam, needle, foot plate ground support plate, or other non-rotatable supporting element or arrangement forming part of the overall propping system.

The jack assembly 100 comprises, generally, a base portion 120 attachable to an end-plate or other end-member of a prop or prop section of the propping system, a collar 140 mounted within a central cylindrical channel A extending through a main cylindrical housing portion 124 of the base portion 120, and an externally screw-threaded rod or bar 160 attachable via one of its ends 164 to a second component (e.g. another prop/prop section or some other component) of the propping system. The collar 140 comprises an internal screw-thread 141 so as to be able to screvvingly receive therein the central threaded portion 162 of the rod or bar 160 upon rotation thereof about the central axis of the cylindrical channel A. That central axis of the cylindrical channel A defines the axis or axial direction of the jack assembly 100, about which axis the collar 140 is freely rotatable within its mounting in the housing portion 124 of the base portion 120 but along which (or parallel to which) axis or axial direction the collar 140 is constrained so as to be not substantially moveable relative to the base portion 120.

The collar 140 has a main tubular, especially generally cylindrical, portion 142 provided with the said internal screw-thread 141 and for screvvingly receiving therein the said central portion 162 of the rod or bar 160, and a handle portion 143 extending from the tubular portion 142 for use in effecting the said free rotation of the collar 140 in its axially constrained mounting in the housing portion 124 of the base portion 120. The handle portion 143 extends transversely outwardly from, especially perpendicularly relative to the axial direction of, the tubular portion 142, from a location at or adjacent the upper axial end of the tubular portion 142. In the illustrated embodiment the handle portion 143 takes the form of a three-armed plate or flange, the three arms 143 being symmetrically and equi-angularly arranged relative to each other around the tubular portion 142 of the collar 140 and manipulatable, e.g. manually or by use of a tool, for effecting the rotation of the collar 140 in its axially constrained mounting in the housing portion 124 of the base portion 120. Thus, the collar 140 is able to freely rotate in either of its rotational directions relative to the rod or bar 160, and in doing so the two parts 140, 160 move relative to each other in a direction along the longitudinal axis of the rod or bar 160, by virtue of their inter-engaged screw-threads 141, 162.

In order to form the axially constrained mounting of the collar 140 in the housing portion 124 of the base portion 120 (i.e. within the channel A therein), the collar 140 comprise the above-mentioned main tubular portion 142 provided with the internal screw-thread 141, and the tubular portion 142 includes an externally radially enlarged portion 144 which engages with a corresponding internally radially reduced portion 124R of the housing portion 124. Such respective radially enlarged and radially reduced portions 144, 124R of the collar tubular portion 142 and the housing portion 124 are defined by, and delimited from the remainder of those respective parts 142, 124 by, a pair of matching annular steps 147 formed in and between the relevant walls of those respective components 142, 124. The relative configurations of the respective steps 147 is such that they constrain the collar 140 so as to be not substantially axially retractable from the housing portion 124 in at least an upward (as shown in the FIGS.) axial direction along the axis of the assembly 100.

The respective externally/internally radially enlarged and radially reduced portions 144, 124R of the collar tubular portion 142 and the housing portion 124 are relatively dimensioned such that there is a small gap 149 (FIG. 9), e.g. of a width in the range of about 0.4 to 0.6 mm (such as around 0.5 mm), between them, in order that the two parts are able to move freely past one another as the collar tubular portion 142 rotates within the housing portion 124. The gap 149 may desirably be filled with a suitable lubricant, e.g. grease or an oil, in order to facilitate that relative rotatable movement between the two parts.

In order to fully assure the overall constrained nature of the mounting of the collar 140 in the housing portion 124 of the base portion 120, the base portion 120 includes an apertured base plate 122 attached (e.g. by welding) to the lower end of the housing portion 124 distal from the stepped portions 147 of the collar tubular portion 142 and the housing portion 124, and which apertured base plate 122 partially occludes the mouth of the channel A in the housing portion 124 so as to prevent the collar 140 being retractable therefrom via that end of the channel A in a downward (as shown in the FIGS.) axial direction along the axis of the assembly 100. (The base plate 122 also provides the means or site by which the base portion 120 of the assembly 100 is attachable to the prop/prop section of the propping system which is to be jacked using the assembly.) In this manner the collar 140 is constrained within its mounting in the housing portion 124 of the base portion 120 so as to be not substantially axially retractable therefrom in either of the two opposite axial directions (upward or downward, as shown in the FIGS.) along the axis of the assembly 100.

In the form of the jack assembly 100 provided ready for use, as in the condition shown in FIG. 3, the externally threaded rod or bar 160 is received in the internally threaded collar tubular portion 142 so as to be engaged with, and internally of, the collar 140, but still screvvingly rotatable relative thereto. Once in that condition, the base plate 122 of the base portion 120 of the jack assembly 100 can be attached in a non-rotatable manner to the respective prop/prop section to be jacked using the assembly 100 (e.g. via the prop's endplate at the relevant end thereof and using suitable attachment means such as one or more bolts, nuts, screws or other anchoring elements), and the rod or bar 160 of the jack assembly 100 can be attached, also in a non-rotatable manner, via its end 164 to the other of the propping components to be jacked using the assembly 100.

As shown in in FIG. 10, the externally threaded rod or bar 160 to which is attachable the second propping component in a non-rotatable manner is an elongate cylindrical rod or bar 160, e.g. of a suitably hard and strong metal or metal alloy (e.g. steel), which comprises a central portion 162 which is provided with the external screw thread, and an end portion 164 which includes attachment means 166 for attachment of that end portion 164 of the rod or bar 160 to the second propping component. That attachment means 166 may for example comprise a through-hole 166 or alternatively a socket, bracket, clip or other anchoring element or feature with which is engageable a suitable secondary anchoring element, e.g. a bolt, nut or screw, which engages the second propping component and so anchors it to the rod or bar 160.

Thus, in putting the jacking assembly 100 to practical use, and in accordance with embodiments of the present invention, in order to effect the desired axial relative position variation or adjustment of the first (e.g. prop/prop section) and second propping components upon the free rotation of the collar 140 within its axially constrained mounting in the housing portion 124, the attachment of the first propping component (e.g. prop/prop section) to the base portion 120 is such that the first propping component (e.g. prop/prop section) and the base portion 120 are substantially axially non-rotatable relative to each other, and further that the attachment of the second propping component to the rod or bar 160 is such that the second propping component and the rod or bar 160 are substantially axially non-rotatable relative to each other too. In this manner, the respective pairs of component parts that are so attached to each other are constrained so as to be substantially axially non-rotatable relative to each other within each pair, thereby enabling the free rotation of the collar 140, using the handle(s) 143, with the rod or bar 160 screvvingly received therein, to effect the axial movement of the rod or bar 160 relative to (i.e. through) the housing portion 124 of the base portion 120 and thus to effect the relative axial movement of the first (e.g. prop/prop section) and second propping components either axially towards or away from one another.

In other words, the above arrangement enables the collar 140 to be rotated within the channel A in the housing portion 124 in either of its rotatable directions, but owing to the axial constraining nature of its mounting in the base portion 120 of the assembly 100 it substantially cannot move relative to the base portion 120 in that axial direction upon that rotation, so upon its rotation the rod or bar 160 itself moves in that axial direction relative to the base portion 120, thereby carrying with it the second propping component attached thereto which thus also moves in that axial direction relative to the base portion 120 which is attached to the first propping component (e.g. prop/prop section).

It is to be understood that the above description of some specific embodiments of the invention in terms of their various features and aspects has been by way of non-limiting example(s) only, and various modifications may be made from what has been specifically described and illustrated whilst remaining within the scope of the invention as set out in the appended claims.

Throughout the description and claims of this specification, the words "comprise" and "contain" and linguistic variations of those words, for example "comprising" and "comprises", mean "including but not limited to", and are not intended to (and do not) exclude other moieties, additives, components, elements, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless expressly stated otherwise or the context dictates otherwise. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless expressly stated otherwise or the context dictates requires otherwise.

Furthermore, through this specification any feature, component, element, integer, characteristic, property, compound, chemical moiety or group described in conjunction with a particular aspect, embodiment or example of the invention is/are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith or expressly stated otherwise.

Claims

CLAIMS1. A jack assembly for use in a propping system for varying or adjusting the relative positions of at least first and second components of the propping system relative to each other, wherein the jack assembly comprises: a base portion attachable to the first component of the propping system, wherein the base portion includes a housing portion having a longitudinal channel extending therethrough, the said longitudinal channel defining an axis of the assembly; an externally screw-threaded rod or bar attachable at or adjacent at least one of its ends to the second component of the propping system, and a collar mounted within the channel of the housing portion of the base portion, wherein the collar is internally screw-threaded so as to be able to screwingly receive therein a portion of the rod or bar upon rotation thereof about the said axis; wherein the collar is mounted within the channel of the housing portion of the base portion such as to be freely rotatable therewithin about the said axis yet is constrained so as to be not substantially moveable relative to the base portion in a direction along the said axis.
2. A jack assembly according to claim 1, wherein the collar comprises a main tubular portion provided with the said internal screw-thread and for screwingly receiving therein the said portion of the rod or bar, and a handle portion extending from the tubular portion for use in effecting the said free rotation of the collar in its axially constrained mounting in the housing portion.
3. A jack assembly according to claim 2, wherein the handle portion extends transversely outwardly from the tubular portion, optionally from a location at or adjacent one axial end of the tubular portion.
4. A jack assembly according to claim 2 or claim 3, wherein the handle portion comprises a plurality of arms symmetrically or equi-angularly disposed around the tubular portion of the collar, each arm being manipulatable for effecting the said free rotation of the collar in its axially constrained mounting in the housing portion.
5. A jack assembly according to any preceding claim, wherein the attachment of the first propping component to the base portion is such that the first propping component and the base portion are substantially axially non-rotatable relative to each other, and further wherein the attachment of the second propping component to the rod or bar is such that the second propping component and the rod or bar are substantially axially non-rotatable relative to each other, whereby the respective pairs of component parts that are so attached to each other are constrained so as to be substantially axially non-rotatable relative to each other within each pair, thereby enabling the rotation of the collar, with the rod or bar screwingly received therein, to effect axial movement of the rod or bar relative to and through the housing portion of the base portion and thus to effect the relative axial movement of the first and second propping components either axially towards or away from one another.
6. A jack assembly according to any preceding claim, wherein the collar comprises a main tubular portion provided with the said internal screw-thread, and the tubular portion includes an externally radially enlarged or radially reduced portion which engages with a corresponding internally radially reduced or radially (respectively) enlarged portion of the housing portion.
7. A jack assembly according to claim 6, wherein the respective externally/internally radially enlarged or radially reduced portions of each of the collar tubular portion and the housing portion are defined by, or delimited from the remainder of those respective parts by, a respective step or stepped portion formed in the relevant wall of the respective component, and wherein the relative configurations of the respective steps or stepped portions are such that they constrain the collar so as to be not substantially axially retractable from the housing portion in a first axial direction.
8. A jack assembly according to claim 6 or claim 7, wherein the respective externally/internally radially enlarged or radially reduced portions of each of the collar tubular portion and the housing portion are relatively dimensioned such that there is a small cylindrical gap between them, optionally in which gap is contained a lubricant, whereby the collar tubular portion and the housing portion are able to move freely past one another as the collar tubular portion rotates within the housing portion.
9. A jack assembly according to any one of claims 6 to 8, wherein the base portion includes an apertured base plate attached to an axial end of the housing portion distal or spaced from the respective steps or stepped portions of the collar tubular portion and the housing portion, and which apertured base plate partially occludes the mouth of the channel in the housing portion so as to prevent the collar being retractable therefrom via that end of the channel, and wherein the collar is constrained so as to be not substantially axially retractable from the housing portion in a second axial direction, that second axial direction being opposite to the said first axial direction.
10. A jack assembly according to any preceding claim, wherein, in the form of the jack assembly provided ready for use, the externally threaded rod or bar is received in the collar so as to be engaged with, and internally of, the collar, but still screwingly rotatable relative thereto.
11. A jack assembly according to claim 10, wherein the portion of the rod or bar that is actually engaged with the collar is a region thereof in or adjacent or near a central portion thereof or intermediate the respective end portions thereof, up to which region the rod or bar has been screwingly inserted axially into the collar so that the assembly is ready for use.
12. A jack assembly according to any preceding claim, wherein the externally threaded rod or bar to which is attachable the second propping component is an elongate cylindrical rod or bar which comprises a central portion which is provided with the said external screw thread and at least one end portion which includes attachment means for attachment of that end portion of the rod or bar to the second propping component.
13. A jack assembly according to any preceding claim, wherein the base portion is attachable to the first propping component by its own respective attachment means, optionally one or more bolts, nuts, screws or other anchoring elements.
14. A jack assembly according to any preceding claim, wherein, in the said propping system, one of the first and second propping components is a prop or prop section.
15. A jack assembly according to claim 14, wherein, in the said propping system, the prop or prop section comprises a pair of back-to-back united channel sections, which are bounded at their longitudinal ends and united securely together by a pair of transverse end plates, optionally with a number of internal bracing members and/or external stiffener elements located and attached to the respective channels sections at various selected points longitudinally therealong.
16. A jack assembly according to claim 14 or claim 15, wherein, in the said propping system, the other of the first and second propping components is either another prop or prop section On which case the jack assembly is usable to interconnect in a length-adjustable or length-variable manner such a pair of prop sections) or some other component of the propping system selected from a beam, needle, foot plate ground support plate, or other non-rotatable supporting element or arrangement forming part of the overall propping system.
17. A base assembly for forming a jack assembly for use in a propping system for varying or adjusting the relative positions of at least first and second components of the propping system relative to each other, wherein the base assembly comprises: a base portion attachable to the first component of the propping system, wherein the base portion includes a housing portion having a longitudinal channel extending therethrough, the said longitudinal channel defining an axis of the assembly; and a collar mounted within the channel of the housing portion of the base portion, wherein the collar is internally screw-threaded for screvvingly receiving therein a portion of a rod or bar attached at or adjacent at least one of its ends to the second component of the propping system and upon rotation of the rod or bar about the said axis; wherein the collar is mounted within the channel of the housing portion of the base portion such as to be freely rotatable therewithin about the said axis yet is constrained so as to be not substantially moveable relative to the base portion in a direction along the said axis.
18. A propping system comprising: at least one first component and at least one second component of the propping system, the relative positions of the first and second components being variable or adjustable relative to each other; and at least one jack assembly according to any one of claims 1 to 16, for effecting the said variation or adjustment of the relative positions of the first and second components relative to each other upon rotation of the rod or bar screvvingly received in the collar mounted within the housing portion of the base portion of the jack assembly.
19. A method of varying or adjusting the relative positions of first and second components of a propping system relative to each other, the method comprising: providing at least one jack assembly according to any one of claims 1 to 16; attaching the base portion of the jack assembly to the first component of the propping system and attaching the rod or bar, at or adjacent at least one of its ends, to the second component of the propping system; rotating the rod or bar, once screvvingly received in the collar mounted within the channel of the housing portion of the base portion of the jack assembly, so as to effect the said variation or adjustment of the relative positions of the first and second components relative to each other.