GB1562551A

GB1562551A - Thermally insulating coupling

Info

Publication number: GB1562551A
Application number: GB99677A
Authority: GB
Original assignee: Josef Gartner and Co
Current assignee: Josef Gartner and Co
Priority date: 1976-01-13
Filing date: 1977-01-11
Publication date: 1980-03-12
Also published as: NL7700066A; DE2601022B2; DE2601022A1; DE2601022C3

Description

(54) A THERMALLY INSULATING COUPLING (71) We, JOSEF GARTNER & Cho., a Germany company of 8883 Gundelfingen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a thermallyinsulating coupling between structural members of relatively high thermal conductivity.

If two structural members made of a material of good thermal conductivity are to be interconnected with satisfactory heat insulation in relation to one another, while at the same time forces can be transmitted in many directions between these members, problems arise in relation to the dimensioning and design of the individual elements of the coupling between the members. The individual elements must be constructed so as to be strong and stable and thus must generally be of large dimensions. However, large elements inevitably have large crosssections which make considerable heat transfer possible.If relatively large intermediate coupling elements are made of a material of poor thermal conductivity, they tend to be very sensitive to mechanical stress since, in general materials which are good thermal insulators such as plastics, tend to be mechanically weak, as compared with metals, particularly as regards tensile strength. For instance, if high tensile forces are involved a plastics screw cannot be conveniently used as a coupling device for connecting two spaced-apart elements of high thermal conductivity. In practice, therefore, a compromise must be reached which takes into account strength on the one hand and heat insulation on the other.

It is an object of the invention to provide a thermally insulating coupling for the transmission of forces between the members coupled, which has a very simple, compact and readily manufacturable structure, and which enables very high forces to be transmitted in many directions, while the heat transfer between the coupled elements is minimal.

According to one aspect of the present invention, there is provided a thermallyinsulating coupling between structural members of relatively high thermal conductivity, comprising a bolt directly engaging one of the members and under tension to couple the members one to the other, the force of said tension being transmitted to the other member by way of a first thermally-insulating element under compression, the members being mutually spaced by a second thermallyinsulating element under compression, the second thermally-insulating element engaging the members so that forces acting on the members and tending to displace one member laterally relative to the other cause shear stress in the second insulating element.

According to another aspect of the present invention, there is provided a thermally insulating coupling between structural members of relatively high thermal conductivity, comprising a bolt directly engaging one of the members and under tension to couple the members one to the other, the force of said tension being transmitted to the other member by way of a first thermally-insulating element under compression, the members being mutually spaced by a second thermally-insulating element under compression, the second thermally-insulating element being positively located with reference to each of the members thereby to isolate the bolt from shear stress arising from forces acting on the members and tending to displace one member laterally relative to the other.

The bolt need be only of very small diameter, since it is subjected in practice exclusively to tensile stressing. The crosssection of the bolt is therefore small and already has some heat resistance. The comparatively long bolt shank means that thick heat insulating elements can be provided for satisfactory heat insulation. However, the bolt itself cannot absorb compressive stresses, nor, due to its length, transverse forces, but the thermally insulating elements provided between the members of high thermal conductivity, absorb compressive forces and also transverse forces.The invention therefore makes use of the knowledge that the forces occurring can be distributed amongst various individual elements particularly suited to withstand such forces, the particular construction of the individual elements being determined in accordance with each particular case and being readily changeable so that if necessary the individual elements can readily be interchanged.

In one embodiment of the invention, at least the thermally insulating element disposed between the one and the other of the structural members is a block.

This block may have an inclined bore whose ends are in the two opposite block sides subject to compressive stressing.

The coupling can be made particularly compact if the bolt extends through at least the insulating element disposed between the structural members.

Preferably, the insulating elements have the same axial length.

Advantageously, the two insulating elements are made of plastics.

In another embodiment of the invention, the head of the bolt, including the associated insulating element is disposed in the inside of the said other structural member.

In one particular application, the invention advantageously enables aluminium facades to be attached to buildings by means of thermally insulating couplings. In such an application, the tensile and shearing forces caused, for instance, by side winds or stormy gusts, operative in the direction of the coupling bolts can be greater by a considerable amount, for instance, by a factor of 5, than the forces operative transversely in relation to the axes of the coupling bolts.

In this special application the couplings embodying the invention on the one hand make use of the high strength of high-grade steel and on the other avoid the need for the cross sections of the high-grade steel coupling bolts to be large, while at the same time enabling bending forces also to be absorbed. This is done by the two insulating elements of very low heat transfer - i.e. very high resistance to thermal conduction, which are made of plastics and cannot absorb high tensile forces.

The insulating elements are subjected to compressive stressing, independently of whether shearing or tensile forces occur in the direction of the bolt axes. Transverse forces caused, for example, by the weight of one structural member are absorbed by the plastics sleeves.

Embodiments of the invention are described below with reference to the accompanying drawings, wherein: Figure 1 is a view in horizontal section, taken along the line I-I in Figure 2, of a connection between structural members incorporating a thermally insulating coupling in one embodiment of the invention; Figure 2 is-a view in vertical section, taken along the line 11-Il in Figure 1, of the embodiment of Figure 1; Figure 3 is a view in horizontal section, taken along the line 111-111 in Figure 2; Figure 4 is a perspective view of a coupling forming another embodiment; Figure 5 is a view in section, along the line IV-IV in Figure 4; Figure 6 is a sectional view, corresponding to Figure 5, of a variant embodiment;; Figure 7 is a sectional view of another embodiment of a coupling according to the invention; Figure 8 shows an advantageous crosssection of an insulating element; Figure 9 is a partial sectional view of yet another embodiment of a coupling according to the invention, and Figure 10 is a plan view, taken along the line V-V in Figure 9, showing an oval insulating element of tapering cross-section..

Figures 1 and 2 show a connection 10, for the transmission of considerable forces in a large number of directions, between a building structure and a facade element. The connection comprises two parts 12, 14, of which the first part 12 is connected to a load-bearing member 16 which is rigidly connected to the building, being concreted into one of its floors, the other part 14 being connected to a facade member 18 which extends vertically at a distance from a wall 20 of the building and can take the form, for instance, of an aluminium wall.

The main supporting element of the first connection part 12 is a U-shaped horizontal supporting member 22 with a baseplate 24 and side webs 26, which extends from the building wall 20 perpendicular thereto, is carried on the concretedin, horizontal load-bearing member 16 and is attached to the bearing member 16, with provision for adjustment substantially in a horizontal plane, by nuts and bolts 28 each of said bolts passing through respective crossed slots 30 in the baseplate 24 and the bearing member 16.The vertical position of the baseplate 24 or its inclination with respect to the bearing member 16 can be adjusted, if necessary, by interposing spacing discs or washers (not shown) as appropriate, between the baseplate 24 and the member 16, so that should the bearing member 16 not be concreted-in precisely level or in precisely the desired horizontal plane, the baseplate 24 and therefore the whole connection part 12 can nevertheless be placed exactly in the desired horizontal plane. Of course, by using suitably dimensioned and arranged spacing members between the member 16 and the baseplate 24 a predetermined inclination of the connection part in any sense can be obtained, if such an inclination, rather than strict levelness should be required in a particular case.

Welded on to the free end face of the supporting element 22 is a vertically disposed end face plate 22 having two bores through which pass respective connecting screws 34 which releasably connect the end face plate 32 to a guide member in the form of an aluminium block 36 which has a vertically extending dovetail-section groove in its face remote from the plate 32, this groove forming a guide for the connection part 14.

The connection part 14 mainly consists of a vertically extending elongate aluminium block 42 of dovetail cross-section which is a close sliding fit in the dovetail-section groove in the block 36. The block 42 is releasably connected to the facade member 18 by means of a thermally-insulating coupling in accordance with the present invention. This coupling consists of two vertically spaced, parallel connecting bolts 38 which extend in the horizontal direction from the interior of the dovetail block 42 and through metal inserted rings 40 and heat insulating plastics sleeves 41a, 41b into the facade member 18 into which the bolts 38 are screwed. The coupling of the facade member 18 (one structural member) to the block 42 (other structural member) is described in more detail later.

To produce a vertically adjustable flotation of the dovetail block 42 in relation to the vertical grooved guide member 36 the dovetail block 42 extends further vertically than the guide member 36, and a lower transverse support 44, is provided which at the lower end of the dovetail block 42 extends transversely thereto in the horizontal direction and has at its two ends respective bores through which vertical screw-threaded spindles or bolts 46 extend freely. At their upper ends the vertical spindles 46 are rotatably mounted with respect to the block 42, for example being rotatably carried by an upper transverse support extending across the top of the dovetail block 42, such an upper transverse support being arranged similarity to an upper transverse support 48 in another embodiment to be described below with reference to Figure 6.

However, as an alternative, the dovetail block 42 can also have at its upper end an integral lateral extension in which the vertical spindle 46 is rotatably mounted. Washers 50 are preferably disposed between the spindles 46 and this lateral extension or upper transverse support to facilitate the rotation of the spindles.

The lower transverse support 44 located loosely on the lower ends of the vertical spindles 46 is retained in a suitable manner, for instance, by nuts 52 screwed onto the ends of the vertical spindle, so that the distance between the upper side of the lower transverse support 44 and the undersides of the washers 50 (Figure 2) or between the upper side of support 44 and the upper side of the upper transverse support or of the integral lateral extension if washers 50 are dispensed with, is slightly larger than the vertical length of the dovetail block 42, thus ensuring that the vertical spindles 46 are free to rotate.

If desired, of course, both the upper and lower transverse supports may be secured to the block 42, or formed as integral lateral extensions of the block 42, the nuts 52 being not screwed up tightly, so that the spindles 46 remain free to rotate with respect to the block 42.

The vertical spindles 46, screw-threaded throughout their length, extend through the guide members 36 in screw threaded engagement therewith, so that when the spindles 46 are rotated, the second connection part 14 is vertically adjusted in relation to the first connection part 12 rigidly attached to the building Figures 4 and 5 show in perspective and section views respectively another embodiment of a connection 10 generally similar to that of Figures 1 to 2, components corresponding to those of the embodiment illustrated in Figures 1 and 2, having like references.The difference between this embodiment and that of Figures 1 and 2 is that in this embodiment the screw-threaded vertical bolts 54, corresponding to the spindles 46 in Figures 1 and 2, do not pass freely through the lower transverse support 44, but instead pass in screw-threaded engagement through screwthreaded bores 56 (Figure 5) in the support 44. Furthermore, the bolts 54 extend freely through vertical bores in the guide member 36 and have heads 58 at their upper ends which rest on the top surface of the guide member 36.

The weight of the facade member 18 together with that of the bolts 54 and the connection part 14, is enough to retain the bolts 54 in the position as illustrated in Figures 4 and 5.

Accordingly, in this embodiment there is advantageously no restraint, other than the weight mentioned, against upward movement of the facade member, said weight being sufficient to ensure stable vertical retention.

This embodiment is of particularly simple construction and if necessary allows for ready vertical adjustment.

Figure 6 shows a variant of the embodiment of Figures 1 and 2, and shows those parts of this variant which differ from the corresponding parts of the variant of Figures 1 and2.

In this variant lower and upper transverse supports 44 and 48 are provided at the top and bottom respectively of the block 42, being, for example, secured to or integral with the block 42. The two spindles 46 in this variant, are freely rotatable in the bores in the supports 44 and 48 through which they pass, but are held captive in the support 48 by collars 60 secured to the spindles 46 adjacent the underside of the support 48, which collars engage the support 48 to prevent upward movement of the spindles with respect to the support 48. Similarly, discs 60 secured to the lower ends of the spindles 46 prevent upward movement of the spindles with respect to the support 44 and conversely prevent downward movement of the support 44 with respect to the spindles.

Of course the construction of the vertical spindles 46 illustrated in Figure 6 is such as to allow very simple, reliable assembly of the individual parts, more particularly of the bottom and top transverse supports 44; 48 and the guide member 36 and secured discs or collars 60.

Figure 3 shows in detail the manner in which the block 42 is coupled with the facade member 18 in the embodiment so far described, Figure 3 being a horizontal section view along the axis of one of the coupling bolts 38. Each bolt 38 extends with clearance through a respective bore 64 through the block 42, the head of the bolt being accommodated in an enlarged counter bore 62 extending from the face of the block remote from the facade member 18. The bolt 38 is screw-threaded at its free end and is screwed into a screwthreaded bore in the facade member 18.

Between the head of the bolt and the facade member 18 are clamped identical heat insulating elements 41a, 41b, annular metal mountings or spacers 40 and a base portion 66 of the block 42. The elements 41a, 41b and 40 encircle the bolt 38.

Each of the mountings 40 comprises an annular radially extending flange and an axially short tubular collar extending in one axial direction from the inner edge of the annular flange. The head of the bolt 48 engages one end face of the radially extending flange of one mounting 40, the shank of the bolt passing through the tubular collar. The othe end face of the last mentioned flange engages one end face of the hollow cylindrical plastics sleeve 41a, which is internally of a diameter such as to receive the tubular collar of the lastmentioned mounting 40, which collar extends for a short distance within the sleeve 41a from the end of the sleeve 41a nearer the head of the bolt. The end of the sleeve 41a remote from the head of the bolt fits closely in a countersunk circular recess formed in the end face of the counter bore 62.

The axial end of the hollow cylindrical plastics sleeve 41b nearer the head of the bolt fits closely in a countersunk circular recess formed around the bore 64 in the end face of the block 42 nearer the facade member 18, whilst the annular flange of the other mounting 40 is interposed between the facade member 18 and the end face of sleeve 41b remote from the head of the bolt, the tubular collar of the last mentioned mounting encircling the shank of the bolt and extending for a short distance into the interior of the sleeve 41b from the end thereof furtherest from the head of the bolt and nearest the facade member 18.

The mountings 40, besides acting as washers, also ensure that the sleeves 41a, 41b are spaced radially from the shank of the bolt and maintain the sleeves 41a, 41b centred with respect to the bolt. Since the circular recesses in the block 42 in which the ends of the sleeves remote from the respective mountings 40 are received ensure that the sleeves are centred with respect to the bore 64, the arrangement described also ensures that the shank of the bolt is centred with respect to the bore 64 and thus ensures that a radial clearance is maintained between the shank of the bolt and the part of the bore 64 extending through the base portion of block 42 (the portion between the end faces of the circular recesses which locate respective axial ends of the sleeves 41a and 41b).

The bolt 38 is screwed tightly into the facade member 18 so that the bolt is in axial tension whereas the sleeves 41a, 41b, the portion 66 of the block 42 and the mountings 40 are in compression. It will be noted that whilst the bolt 38 is directly connected to the facade member 18 it is only indirectly connected to the connection part 14, and in particular to the block 42.

It will be appreciated that the elements associated with each of the bolts 38 are identical, so that Figure 3 can be regarded as a view in section along the axis of either bolt 38.

It is found that if the outside temperature drops - e.g. in the case of a cold facade member 18 made, for instance, of aluminium, in practice no heat can be transmitted from the inner connection part 14 to the cold facade member 18. The coupling described is extremely stable and light in weight and also has the property of satisfactory thermal insulation.

Moreover, the very high tensile of compressive stresses caused, for instance, by gusts of wind or storms, and acting in the axial direction of the bolt 38 can be absorbed either by the plastics sleeve 41a or the plastics sleeve 41b, which in any case are subject to compressive, not tensile stressing. As shown in Figure 3, the plastics sleeves 41a, 41b have a circular shape and are therefore extremely resilient also to transverse or shearing forces, so that in practice there can be no bending of the sleeves 41a or 41b, or of the bolts 38, due to the weight G of the facade member. The outer end of each counter bore 62 can be closed by a closure 68 fitted in a circular recess around the bore 62 in the face of the block 42 remote from facade member 18.

In the embodiment of Figure 7 which is otherwise similar to that of Figures 1 and 2 and in which like parts have like reference numerals, a different form of thermally insulating coupling is used between the facade member 18 and the dovetail-section block 74, (which corresponds to the block 42 and is externally of the same form). In the embodiment of Figure 7, the dovetail-section block 74 is hollow so that the block 74 is in effect a box. The heads of the bolts 38 are accommodated within this box and the shanks of the bolts 38 pass with clearance through holes in the wall of the box which is nearest to, and parallel with, the facade member 18, into which the ends of the bolts 38 are screwed, as in the previous embodiments.

Both bolts 38, pass with clearance through respective holes in a single plate 70 accommodated within the block 74, but out of contact with the walls of the block 74, the plate 70 extending parallel with the wall of the block 74 which is nearest to and faces the facade member 18. A heat insulating block 72 is clamped between the plate 70 and the last mentioned wall of the block 74 and a further heat insulating block 76 is clamped between the last-mentioned wall of the block 74 and the facade member 18.The block 72 is located in recesses in the plate 70 and the last-mentioned wall of the block 74, so as to be immovable with respect to the plate 70 and the block 74 in directions transverse to the axial direction of bolts 38, and similarly the block 76 is located in recesses in the last mentioned wall of the block 74 and in the facade member 18 so as to be immovable with respect to the block 74 and member 18 in directions transverse to the axial direction of bolts 38. A bore, inclined with respect to the faces of the block 76 which engage the block 74 and facade member 18 is formed through the block 76, this bore preferably lying in the plane of bolts 38. The embodiment of Figure 7 also provides a stable, compact, heat insulating coupling in which the bolts 38 are subjected solely to tensile stressing, while the other possible forces are absorbed by the blocks, 72, 74.An inclined bore can also be formed in the block 72, such inclined bores being easily formed, and due to the cross-sectional reduction of the insulating block resulting from such a bore, the heat transfer through such an insulating block is reduced, while transverse forces, for instance, due to the weight G of the facade member, are transmitted without the block changing shape.

Figure 8 shows in cross-section an insulating block which may be used in place of the block 72 and/or 76 in Figure 7. This block is hollow, with a substantial internal cavity so that the cross-section effective for heat transfer is further reduced, but side wall corss-sections are provided which so taper in the axial direction of the bolts 38 that the transverse force due to the weight of the facade element is absorbed to the optimum extent and transmitted by the block.

In a variant of the embodiment of Figures 1 to 3, illustrated in Figures 9 and 10, the insulating sleeve 41b is replaced by an insulating element in the form of a ring 82 the mounting 40 adjacent the facade member 18 being dispensed with and the ring 82 being located in corresponding recesses in the dovetail block and the member 18. The ring 82 is elongate in the longitudinal direction of the dovetail block and the crosssection passage through the ring extends in a direction inclined with respect to the axial direction of the bolts 38, and parallel with the plane of the bolts 38, so that the walls of the ring taper in section in the plane of the bolts 38 in the manner shown in Figure 9. Even using a coupling of this kind forces can be transmitted in many directions between the elements coupled whilst ensuring minimal heat transfer of the elements coupled.

The heat resistance of the bolts 38 in the embodiments described is less than 10% of the total heat resistance of the coupling. If the same resistance to heat flow were to be provided only by the connecting bolts corresponding to bolts 38, these bolts would have to be much longer and much thinner in construction, and this would make no sense from the constructional aspect. The resistance to heat flow between the elements coupled is therefore determined, in the embodiments described, primarily by the insulating plastics parts and thus by the material, length and cross-section of these plastics parts. Since the plastics material still contributes to heat transfer, conveniently a cross-section of the plastics parts is provided only where forces are to be transmitted.The provision of cavities in zones of the plastics parts which are not required to transmit forces, is made not so much for reasons of saving plastics material, as for reasons of increasing the resistance to heat flow of the whole coupling.

Another advantage of the couplings described, more particularly if used for applying facade members to the walls of buildings, is that in the event of fire, the bolts 38 of suitable cross-sectional dimensions ensure high security even if the building should be completely burnt out, since in the latter case even although the plastics parts drop out and are destroyed, and therefore the facade members take up an inclined and shifted position, the facade members are nevertheless retained by the bolts 38.

Another advantage is that the plastics parts are stressed solely by those forces which they are best adapted to absorb. Thus, as a rule, plastics are not able to absorb tensile forces very well but can absorb compressive forces much better. The couplings described take this into account.

WHAT WE CLAIM IS: 1. A thermally insulating coupling between structural members of relatively high thermal conductivity, comprising a bolt directly engaging one of the members and under tension to couple the members one to the other, the force of said tension being transmitted to the other member by way of a first thermallyinsulating element under compression, the members being mutually spaced by a second thermally-insulating element under compression, the second thermally-insulating element engaging the members so that forces acting on the members and tending to displace one member laterally relative to the other cause shear stress in the second insulating element.

2. A thermally insulating coupling between structural members of relatively high thermal conductivity, comprising a bolt directly engaging one of the members and under tension to couple the members one to the other, the force of said tension being transmitted to the other member by way of a first thermally-insulating element under compression, the members being mutually spaced by a second thermally-insulating element under compression, the second thermally-insulating element being positively located with reference to each of the members thereby to isolate the bolt from shear stress arising from forces acting on the members and tending to displace one member laterally relative to the other.

3. A coupling according to claim 1 or 2, wherein the second thermallyinsulating element is partially received in a mating recess in the other member.

4. A coupling according to claim 2, wherein the second thermally-insulating element is partially received in respective mating recesses in the members.

5. A coupling according to any one of the preceding claims, wherein the thermallyinsulating elements each freely surround the bolt.

6. A coupling according to claim 1, wherein at least the second thermally insulating element has a cross-section of circular configuration.

7. A coupling according to claim 2 or 4, wherein the second thermally insulating element has a cross-section of oval configuration and has a wall thickness which varies along the length dimension of the element extending between the members.

8. A coupling according to claim 2 or 4, wherein at least the second thermallyinsulating element is a block.

9. A coupling according to claim 8, wherein the block has a through bore on an axis inclined to the mutually opposite faces of the block subject to compressive stress.

10. A coupling according to claim 1, or claim 3 or 5 when dependent from claim I, or claim 6, wherein the first and second thermallyinsulating elements have the same crosssectional configurations.

11. A coupling according to any one of the preceding claims, wherein the first and second thermally insulating elements have the same lengths.

12. A coupling according to any one of the preceding claims, wherein the thermally insulating elements are of plastics material.

13. A coupling according to any one of the preceding claims, wherein the head of the bolt and the first thermally insulating element lie inside the said other member.

14. A coupling according to claim 13, wherein access to the inside of the other member is closed by a removable cover.

15. A coupling according to any one of the preceding claims, wherein compressive force is transmitted from the head of the bolt to the first thermally-insulating element by way of a metal spacer.

16. A coupling according to claim 1, substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

17. A coupling according to claim 2, substantially as hereinbefore described with reference to and as shown in Figure 7 or Figures 7 and 8 or Figures 9 and 10 of the accompanying drawings.

Having regard to the provisions of Section 9 (1) of the Patents Act 1949, reference is directed to the claims of our co-pending patent application No. 997/77 (Serial No.

1 562 552).

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. are stressed solely by those forces which they are best adapted to absorb. Thus, as a rule, plastics are not able to absorb tensile forces very well but can absorb compressive forces much better. The couplings described take this into account. WHAT WE CLAIM IS:

1. A thermally insulating coupling between structural members of relatively high thermal conductivity, comprising a bolt directly engaging one of the members and under tension to couple the members one to the other, the force of said tension being transmitted to the other member by way of a first thermallyinsulating element under compression, the members being mutually spaced by a second thermally-insulating element under compression, the second thermally-insulating element engaging the members so that forces acting on the members and tending to displace one member laterally relative to the other cause shear stress in the second insulating element.

1 562 552).