GB2269647A

GB2269647A - Compliant support system

Info

Publication number: GB2269647A
Application number: GB9217287A
Authority: GB
Inventors: Geoffrey David Scowen
Original assignee: SULCATED SPRINGS Ltd
Current assignee: SULCATED SPRINGS Ltd
Priority date: 1992-08-14
Filing date: 1992-08-14
Publication date: 1994-02-16
Anticipated expiration: 2012-08-14
Also published as: GB2269647B; GB9217287D0

Abstract

A resilient support unit comprises one or more sulcated springs and end fittings for mounting the unit between relatively movable elements. In one form, a spring (80) has its lower end secured between opposed lower ends of spaced arms (84) of a yoke (82), and its upper end guided between opposed upper ends of the arms. The lower end of the yoke is mountable on a fixed support whilst the upper end of the spring is adapted to support e.g. pipework by means of end fittings (76). The spring (80) and the yoke (82) are formed of fibre reinforced plastics material. Several other embodiments are described. <IMAGE>

Description

Title: Compliant Support System This invention relates to resilient support units such as may be used to support pipework either below or above a fixed support, or to space adjacent runs of pipework from one another, or to space pipework laterally from a fixed element, or to support other items or equipment, e.g. rotating machinery.

A known form of resilient support unit, for example for the suspension of pipework, comprises a metal helical coil spring located within a cylindrical housing. A connector rod extends through the interior of the spring within the housing and is secured to a circular plate at its upper end with the plate resting on the uppermost convolution of the spring, the lowermost convolution of the spring being supported on a lower end closure of the housing. The lower end of the connector rod extends downwardly through the lower closure of the housing for connection to a pipe clamp and an upper closure of the housing is provided with a suspension lug for connection to a fixed support. Such a resilient support unit finds many applications such as for example in power plant, on and off-shore petrochemical installations and in food processing plant.To meet the differing environmental requirements of such applications such resilient suspension units may have their metal component parts completely coated internally and externally, the spring may be neoprene or plastic coated, the housing may be galvanised or the complete unit may be produced of austenitic stainless steel.

These differing requirements lead to increased production costs. Also, the units are heavy due to their all metal construction. It is an object of the present invention to provide a new or improved resilient support unit which is light in weight and economical to manufacture whilst being able to offer all the operational properties of known support units.

In accordance with the broadest aspect of the invention there is provided a resilient support unit comprising one or more sulcated springs of a fibre reinforced plastics material wherein said unit has fittings at opposite ends thereof :enabling the unit to be connected between two elements subject to movement towards or away from one another. Such a support unit may be utilised either to suspend an article such as pipework below a fixed support, or to support an article such as pipework above a fixed support. In either of these two circumstances one of said two elements comprises a fixed support and the other of said elements comprises the article, such as pipework, to be supported.

Alternatively such a resilient support unit may be utilised to space adjacent elements and to restrain them against excessive movement relative to one another; in such a circumstance each of said two elements may comprise the article, such as pipework, to be restrained.

The term "sulcated spring" as used throughout this specification relates to a spring comprising a strip of fibre reinforced plastics material in the form of a zig-zag having a plurality of limbs connected by reflex portions, the longitudinal centreline of the strip lying substantially in a single plane. Such a spring is disclosed in International patent application publication number W085/00207.

According to one of the broadest aspects of the invention a said connection fitting at one end of the sulcated spring comprises a support element formed integrally with the sulcated spring. Conveniently the resilient support unit comprises two sulcated springs each having an end said support element in the form of a semi-circular pipe support, the two springs being arranged in the said unit so that the said pipe supports are opposed to one another and define a circular pipe support releasably securable about a pipe to be supported by the unit.

In another of the broadest aspects of the invention the support unit comprises a pair of relatively movable yoke members between which is connected a said sulcated spring, the arrangement being that relative movement between said yoke members imparts compression or tension to the sulcated spring. A support element, for example a circular pipe support, may be formed integral with one of said yoke members.

Each of said yoke members may comprise a pair of laterally spaced arms and an interconnecting portion with the said arms of one yoke being slidably movable relative to the arms of the other yoke, the sulcated spring being located between the yoke arms and having its longitudinal centreline contained within the plane containing the yoke arms. The arms and interconnecting portions of each yoke member are preferably formed of a fibre reinforced plastics material with the fibres of the reinforcement extending unidirectionally of the longitudinal axis of each said arm.

In one embodiment of the support unit of the invention wherein the unit is usable to suspend an article e.g. pipework from a fixed support, a first one of said yoke members comprises a pair of laterally spaced arms, an upper interconnecting portion securable to a said fixed support, and a lower interconnecting portion to which the lower end of the sulcated spring is attached.

A second yoke member of such a support unit comprises a pair of laterally spaced apart arms each having a complimentarily relieved portion within which is slidable a corresponding arm of the said first yoke member, an upper interconnecting portion to which the upper end of the sulcated spring is attached, and a lower interconnecting portion to which the article to be suspended is securable. Thus when an article, such as pipework, is attached to the lower interconnecting portion of the said second yoke member, and the upper interconnecting portion of the said first yoke member is secured to the said fixed support, the weight of the pipework will cause compression of the sulcated spring between the two other interconnecting portions to which the respective ends of the spring are attached.

In an alternative embodiment of the support unit of the invention it may be usable to support an article e.g. pipework above a fixed support. In a said unit used for such a purpose there may be provided a first yoke member comprising a pair of laterally spaced apart arms and only one upper interconnecting portion to which the upper end of the sulcated spring is attached, the lower ends of the arms being free.A second yoke member may comprise a pair of laterally spaced apart arms each of which is slidable within a complinientarily relieved portion of a corresponding arm of the first yoke member, a lower interconnecting portion to which the lower end of the sulcated spring is attached and which is mountable on the said fixed support, and an upper interconnecting portion affording guide means around upwardly extending portions of the upper interconnecting portion of the said first yoke member. Said upwardly extending portions include attachments for an article such as pipework to be supported thereon and said portions are movable vertically within the guide means relative to the upper interconnecting portion of the second yoke member.

Thus when an article such as pipework is supported by the unit the weight of the pipework causes compression of the sulcated spring between the upper interconnecting portion of the first yoke member and the lower interconnecting portion of the second yoke member to which the respective ends of the spring are attached.

In further alternative embodiments of the support unit of the invention, the unit is used as a resilient sway brace to restrain adjacent articles, such as e.g. adjacent runs of pipework, against excessive vibrations and shock forces. Such a unit usable as a sway brace may comprise a yoke member having a pair of laterally spaced apart arms, a first interconnecting portion attachable to a first said article and a second interconnecting portion having a central aperture through which passes a connecting rod the outer end of which is attachable to a second said article. The rod may extend between the yoke arms and between the limbs of two opposed sulcated springs each having an end attached to said second interconnecting portion. An inner end of the connecting rod located between the two springs is attached either directly or indirectly to the other ends of the two springs whereby, when the sway brace is connected between two adjacent said articles, movement apart of said articles imparts compression to the sulcated springs and movement together of the said articles imparts tension to the springs.

In another simpler form of suspension unit usable as a sway brace, a single sulcated spring may be attached at its ends between two relatively slidable spring supports each of which supports is attachable to a said article to be restrained whereby movement together of two said articles imparts compression to the sulcated spring and movement apart of the said articles imparts tension to the spring.

Means for adjustment, e.g. an adjustment collar, to provide a preload in the or each spring of the support unit may be provided.

Each of the sulcated springs utilised in a resilient support unit according to the invention is preferably formed with each of the reflex portions of the spring having a curvature of parabolic form between each two adjacent limbs of the spring. Each of the said limbs is preferably formed so as to provide a centre portion thereof which is of a greater thickness than the thickness of the portions of each limb adjacent each associated reflex portion.

Other features of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawings wherein: Figure 1 is a perspective view of a resilient support unit constructed in accordance with the invention wherein a single sulcated spring is arranged between two yokes and wherein the unit is usable for pipework suspension below a fixed support; Figure 2 is a perspective view of an alternative yoke form of single spring unit for use::in supporting pipework above a fixed support; Figure 3 is a perspective view of a simple double sulcated spring pipework suspension unit wherein the pipework is secured directly to the lower ends of the springs; Figure 4 is a perspective view of a support unit usable as a sway brace and including two sulcated springs; Figure 5 is a perspective view of another sway brace form of support unit using a single sulcated spring; and Figure 6 comprises a number of diagrammatic illustrations of different applications of the support units illustrated in Figures 1 and 2.

Referring to Figure 1 of the drawings there is illustrated a resilient support unit intended for the suspension of pipework below a fixed support (not illustrated). The unit comprises a first yoke member 10 securable to the fixed support and a second yoke member 12 to which the pipework is securable, the two yokes being movable relative to one another and having a sulcated spring 14 connected therebetween as described below. The first yoke member 10 which is attachable to the fixed support comprises a pair of spaced apart parallel elongated planar arms 16, the upper ends of which are connected by an upper interconnecting portion and the lower ends of which are connected by a lower interconnecting portion.The upper interconnecting portion comprises two opposed elongated planar elements 18 each of which is formed integral with an associated arm 16, the inner end of each said element 18 being formed with an integral upstanding portion 20 substantially parallel to the arms 16 and an integral end portion 22 substantially parallel to the elements 18 and extending back towards an associated arm. Alternatively an end portion parallel to upstanding portion 20 could be provided. As illustrated, the two adjacent upstanding portions 20 of the upper interconnecting portion are bolted together although they may be secured together in any other suitable manner.Although not illustrated in Figure 1, the centre portion of the interconnecting portion defined by the upstanding and end portions 20 and 22 is securable to a fixed support, such as for example a girder or beam, by any suitable form of attachment means.

The lower interconnecting portion of the first yoke member 10 comprises two opposed elongated planar elements 24 each of which is integral with an associated arm 16 and each of which includes an integral downwardly extending end element 26 parallel to a said arm. As will be further described below, said end elements are spaced apart to receive the lower end of a sulcated spring 14 secured therebetween by means of a clamping collar 28 or other securing means.

The second yoke member 12 of the support unit of Figure 1 is of substantially similar configuration to that of the first yoke member 10 and includes a pair of spaced apart parallel elongated planar arms 30 and upper and lower interconnecting portions. As illustrated in Figure 1, the arms 30 of the second yoke member 12 are relieved in the form of slots 32 within which the corresponding arms 16 of the first yoke member 10 are slidably received. The upper interconnecting portion of the second yoke member 12 comprises two opposed planar elements 34 having respective upstanding end portions 36 spaced apart to receive the upper end of the sulcated spring 14 secured therebetween by means of a clamping collar 38 or other securing means.The lower interconnecting portion of the second yoke member 12 comprises two opposed planar elements 40 each formed with an integral downwardly extending limb 42 for the securing thereto of a pipework attachment. As shown in the principal drawing of Figure 1, the pipework attachment comprises a plate 44 having two downwardly extending bolts 46 secured therein for a suitable pipework clamp attachment,the plate 44 being secured as by a clamping collar 48 between spaced apart outwardly flanged lower end portions 50 of the limbs 42. As shown in the detail drawing of Figure 1, an alternative form of clamp attachment may comprise two opposed semi-circular elements 52 having upper and lower clamping bolts 54, and slots within which outwardly extending lower flanged portions 56 of the limbs 42 may be received.

The sulcated spring 14 comprises a strip of fibre reinforced plastics material in the form of a zig-zag having a plurality of limbs 58 connected by reflex portions 60, the longitudinal centreline of the strip lying substantially in a single plane which is itself contained within the same plane containing the arms 16 and 30 of the two yoke members 10 and 12. Such a spring is disclosed in International patent application publication number W085/00207. Each of the reflex portions 60 of the spring preferably has a curvature of parabolic form between each two adjacent limbs 58 of the spring and, although not illustrated, it is also preferred that each limb 58 has a centre portion thereof which is of a greater thickness than the thickness of the portions of each limb adjacent each associated reflex portion 60.

The uppermost and lowermost limbs of the spring 14 are each formed with a respective integral flange 62 and 64 on the centreline of the spring and, as mentioned above, each of said flanges is clamped by a respective clamping collar 38 and 28 between the respective end portions of the said interconnecting portions of the yoke members.

As illustrated in Figure 1, a calibration scale 66 is marked on the outer faces of the relatively slidable arms 16 and 30 of the yoke members whereby, in use, the correct loading and any preset load which may be applicable on the spring 14 may be checked and excessive relative displacements between the arms may be observed. In use, when pipework is suspended by the unit, compressive forces will be imparted to the sulcated spring 14 which will assume a passive position in compression which may be visually checked by the aforesaid calibration markings.

In Figure 2 of the drawings there is shown a somewhat similar resilient support unit to that shown in Figure 1, the principle difference being that the unit of Figure 2 is intended to support pipework above a fixed support element 68.

A first yoke member 70 comprises two spaced apart parallel elongated planar arms 72 each of which has a lower free end and which includes an upper interconnecting portion having opposed planar end elements 74 and upstanding flanges 76 which are themselves bolted together, or otherwise secured, and which receive pipework on an upper surface thereof with the pipework being secured thereto by an appropriate fitting (not illustrated). The upstanding flanges 76 of the upper interconnecting portion of this first yoke member 70 define a space between which is clamped an upper end flange 78 of a sulcated spring 80.

A second yoke member 82 comprises two spaced apart parallel elongated planar arms 84 and upper and lower interconnecting portions, each of the said arms 84 being slidably received within complementary elongate slots formed in the arms 72 of the first yoke member and including calibrations 86 on the outer faces of the said arms. The lower interconnecting portion of the second yoke member 82 comprises opposed planar elements 88 with internal downwardly extending end portions 90 for mounting on the fixed support 68 and which receive between them a lower end flange 92 of the sulcated spring 80, which may be secured by being clamped therebetween or by other means.The upper interconnecting portion of the second yoke member 82 comprises opposed planar elements 94 having upstanding spaced apart end portions 96 defining a guideway through which extends the clamping flanges 76 of the first yoke member 70, a retaining collar 98 being assembled around the outside of the portions 96. The flanges 76 of the first yoke member can thus move freely in a vertical plane between the end portions 96 whereby, when pipework is supported on the upper surface of the flanges 76, they may move downwardly through the guide means afforded by the end portions 96 imparting compression to the sulcated spring 80.

Movement of the pipework relative to the fixed support is subsequently accommodated by the resilience of the sulcated spring and the movement of the flanges 76 between the end portions 96.

A simpler form of resilient support unit for suspending pipework 100 below a fixed support 102 is shown in Figure 3 of the drawings. In this embodiment a pair of opposed sulcated springs 104 - 106 are provided each of which is formed with an integral lower end portion 108 of semi-circular form whereby, when the two springs are assembled as shown in Figure 3, the two opposed semi-circular portions 108 define a clamp for pipework 100 to be suspended below the fixed beam 102 to which the upper ends of the sulcated springs are bolted or otherwise secured. The lower ends of the semi-circular clamping portions 108 are each provided with an outwardly extending flange 110 whereby said flanges may be clamped together by a collar 112 slid over the flanges to retain the pipework in position relative to the springs.

In Figures 4 and 5 of the drawings there are illustrated embodiments of resilient support unit in accordance with the invention wherein the unit is utilised as a lateral sway brace between adjacent articles such as for example two adjacent horizontal runs of pipework. In the embodiment illustrated in Figure 4, the unit comprises a yoke member having two spaced apart parallel elongate planar arms 114 and an interconnecting portion between the arms at each end thereof. A first interconnecting portion comprises a pair of opposed inclined planar end elements 116 each of which is integral with a respective arm 114 and each of which includes an end flange 118 parallel to the arm whereby the said flanges may be clamped together such as by the clamping collar 120 illustrated.

Said flanges 118 may conveniently also include a coaxial aperture 122 extending through the flanges for the securing thereto of one of the articles to be restrained against movement. The other interconnecting portion comprises a pair of opposed planar end elements 124, end flanges 126 and a clamping collar 128 similar to those of the first interconnecting portion but wherein the end elements 124 extend substantially perpendicular to the respective arms 114. A central bore extends through the second interconnecting portion providing guide means for a connecting rod 130 slidably received therein, the free end 132 of the rod which extends out of the yoke member being securable to the other article to be restrained. A screw-threaded adjustment collar 132B on the rod 132 allows a spring preload to be set when required.The inner end of the rod extends within the yoke between two opposed sulcated springs 134 - 136 having ends secured to the end elements 124 of the second interconnecting portion such as, for example, by means of the ends of the springs extending through slots formed in the end elements 124. The inner end of the connecting rod 130 is secured by means of an intermediate plate 138 to end flanges 140 of the two springs whereby, when the two articles to be restrained move apart from one another compression is imparted to the springs and, conversely, when the two articles move together tension is imparted to the springs.

An alternative form of sway brace is illustrated in Figure 5 wherein a single sulcated spring 142 is secured between opposed respective abutment faces 144 and 146 on each of two relatively slidable support members 148 and 150.

The support member 148 has a respective end portion 152 and 154 retained in slidable relationship with a corresponding end portion 156 and 158 of the other support member 150 and means such as apertures 160 whereby articles to be restrained against movement relative to one another may be connected to a respective end portion.

In all of the embodiments described above the respective yoke members and support members all conveniently comprise fibre reinforced plastics mouldings wherein the fibres comprising the reinforcements extend unidirectionally of the longitudinal axis of the various parts of each respective said member.

In Figure 6 of the drawings there is illustrated a series of applications whereby pipework may be supported relative to a fixed support utilising resilient support units as described and illustrated with respect to Figures 1 and 2 of the drawings.

Each of the embodiments of support unit above described may if required be provided with safety guard means to prevent access by personnel, e.g.

installation/maintenance personnel, to "pinch" regions such as may be established by the spring or springs in the unit. For example, in the embodiment of Figure 1, a mesh material, e.g. of plastics, could be fixed to arms 30 and planar elements 34, 40, on each side of the units.

Resilient support units produced in accordance with the invention offer substantial weight savings in comparison with known metal helical spring/metal casing constructions. Other advantages include low corrosion rates, both electrical and thermal insulation properties, low maintenance costs, ease of installation and low production costs. The use of fibre reinforced plastics materials also reduces vibration and noise transmissions.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A resilient support unit mountable between elements subject to relative movement therebetween comprising a sulcated spring (as herein defined) of a fibre reinforced plastics material and an end fitting at each end of the unit adapted to be mountable on a respective one of said relatively movable elements whereby said spring is subject to longitudinal compression or tension upon relative movement between said elements when said unit is mounted therebetween.

2. A resilient support unit as claimed in claim 1 including an elongate guide yoke disposed in a plane containing said spring, one end of said spring being connected to one end of said yoke and means being provided for the guidance of the other end of said spring relative to said yoke during relative movement between said spring and said yoke, said other end of said spring and said one end of said yoke being adapted for mounting respectively on said relatively movable elements.

3. A resilient support unit as claimed in claim 1 or claim 2 including a pair of relatively movable yoke members between which is connected a said sulcated spring, each of said yoke members including a said end fitting.

4. A resilient support unit as claimed in claim 3 wherein each of said yoke members comprises a pair of laterally spaced arms and an interconnecting portion, each of said arms of one said yoke member being slidably movable relative to a corresponding arm of the other said yoke member, said spring being located between the arms of the yoke members with its longitudinal centre line contained within a plane containing said arms.

5. A resilient support unit as claimed in claim 3 or claim 4 for the suspension of an article from a fixed support wherein, in use, a first one of said yoke members comprises a pair of laterally spaced arms, an upper interconnecting portion movable on a said fixed support, and a lower interconnecting portion to which the lower end of said spring is connected; and a second one of said yoke members comprises a pair of laterally spaced arms slidably movable relative to the arms of said first yoke member, an upper interconnecting portion to which the upper end of said spring is connected, and a lower interconnecting portion mountable to the said article which is to be suspended.

6. A resilient support unit as claimed in claim 1 or claim 2 for the support of an article above a fixed support wherein, in use, there is provided a guide yoke comprising a pair of laterally spaced arms disposed in a plane containing said spring, a lower interconnecting portion to which the lower end of said spring is connected and which is mountable on a said fixed support and an upper interconnecting portion affording guide means for the upper end of said spring, said upper end of said- spring being mountable to a said article to be supported.

7. A resilient support unit as claimed in claim 3 or claim 4 for the support of an article above a fixed support wherein, in use, a first one of said yoke members comprises a pair of laterally spaced arms and an upper interconnecting member to which the upper end of said spring is connected; and a second one of said yoke members comprises a pair of laterally spaced arms each of which is slidably movable relative to a corresponding arm of said first yoke member, a lower interconnecting portion to which the lower end of said spring is connected and which is mountable on a said fixed support, and an upper interconnecting portion affording guide means for parts of the upper interconnecting portion of the first yoke member to which the upper end of said spring is connected; said parts being mountable to a said article to be supported.

8. A resilient support unit as claimed in claim 1 or claim 2 for use as a restraint brace between adjacent articles comprising a yoke member having a pair of laterally spaced arms, a first interconnecting portion mountable to a first one of said articles, and a second interconnecting portion having an aperture through which passes a connecting rod a free end of which is mountable to a second one of said articles, a said spring being connected between the other end of the connecting rod and the yoke.

9. A resilient support unit as claimed in claim 8 wherein the connecting rod extends between said arms of the yoke member and between two said sulcated springs each having an end connected to said second interconnecting portion.

10. A resilient support unit as claimed in claim 1 or claim 2 for use as a restraint between adjacent articles wherein a said spring is connected at its ends between two relatively slidable yoke members each of which is mountable to a respective one of said articles.

11. A resilient support unit as claimed in any of claims 2 to 10 wherein the or each of said yokes in formed of a fibre reinforced plastics material.

12. A resilient support unit as claimed in claim 1 comprising a said spring having a said end fitting integral therewith.

13. A resilient support unit as claimed in claim 12 comprising two said springs arranged in side by side relationship, two adjacent ends of said springs together defining a said end fitting.

14. A resilient support unit as claimed in any one of the preceding claims wherein at least one of said end fittings is adapted for mounting to pipework.

15. A resilient support unit as claimed in any one of the preceding claims wherein the or each said spring is formed with its reflex portions having a curvature of parabolic form.

16. A resilient support unit as claimed in any one of the preceding claims wherein each of the limbs of the or each said spring has a centre portion which is of a greater thickness than the thickness of the portions of each limb adjacent each associated reflex portion.

17. A resilient support unit constructed and arranged substantially as hereinbefore described with reference to any one of the accompanying drawings.

18. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.