AU741870B2 - Electro-conductive tube or cable clamp - Google Patents

Description

6884 Britta DAUME A DEVICE FOR CONTACTING IN PARTICULAR ELONGATED.

ILLUSTRATIVELY SUBSTANTIALLY CYLINDRICAL BODIES SUCH AS CABLES OR PIPES/TUBES Field of the Invention The present invention relates to a device for contacting, in particular, elongated, illustratively substantially cylindrical bodies such as cables or pipes or tubes, where hereafter the word "pipe" also includes the meaning of "tube".

BackQround of the Invention A device of this species is known for instance from the European patent document 0,744,788 Al to contact in electrically conducting manner an electrically conducting outside surface in particular of a cylindrical body such as a cable or a pipe. In its assembled position the said device comprises a base structure resting against the body to 6884 be contacted and consisting of an elastic metallic strap coated with an elastic rubber material.

The known device is assembled in simple manner. However its manufacture is complex and hence costly.

Obiects and Summary of the Invention The objective of the present invention is to create a device of the kind as set forth above and free of the drawback of the prior art device, the device of the present invention being simpler and thereby more economical.

In the invention the elastic material at least in part, preferably wholly, consists of at least one thermoplastic elastomer (TPE). Thermoplastic elastomers evince properties similar to those of plastics and are easily processed. Illustratively the base structure to the extent it is composed of an elastic material can be made by injection molding if using a thermoplastic elastomer. Moreover it is feasible to extrude the TPE base structure into a band. Besides the thermoplastic elastomer, the base structure also may comprise a further elastic material such as vulcanized rubber.

The thermoplastic elastomers offer another advantage in that mixing is not required immediately before processing. Instead these materials are available in a ready-to-process state in which they may be stored.

6884 Thermoplastic elastomers offer the special advantage that they quickly harden and that vulcanization is unnecessary. As a result material processing is shortened, for instance when injection-molding the required dwell time in the injection mold is shortened, shortening the operational cycles and hence making the manufacture of the device of the invention more economical.

Furthermore thermoplastic elastomers are characterized by high ageing stability. They also offer the following advantages: excellent permanent resistance to bending fatigue, S0 high temperature resistance high impact resistance, high resistance to chemicals and weathering, good electrical properties, high tear and abrasion resistance, feasibility of co-injection molding and coextrusion with polyolefins, thermoplastic elastomers are easily dyed by pigments or colorants, thermoplastic elastomers are ecological because recyclable and because dangerous vapors such as nitrosamines as a rule are not generated during processing.

The term "contacting" in the sense of the invention covers mechanical and/or electrical contact. In the latter case the device is fitted with contact means to implement an electrically conducting connection between the body to be contacted and a conductor, for instance a grounding cable.

6884 Fundamentally the base structure of the device of the invention may be made substantially rigid. However, in a further development of the invention, the base structure is flexible. In this latter embodiment the base structure by its flexibility matches the surface of the body to be contacted. In this manner even strongly non-planar or curved bodies may be contacted. The bodies to be contacted may be of many geometries, for instance plates, bars or pipes of arbitrary cross-sections.

In another embodiment of the invention, the base structure design is such that in its assembled position it encloses the body to be contacted preferably like a ring or a bush. As a result, when contacting cables or pipes for instance, the base structure is held reliably against the body to be contacted.

In another appropriate embodiment of the invention, the base structure is designed as a tensioned clamp around the body to be contacted. In this embodiment there is simplification of device assembly.

The base structure of the device of the invention may be in several parts, for instance to contact a cable or pipe by several illustratively semi-annular parts consecutively mounted in the circumferential direction when in the assembly position.

Advantageously however the base structure shall be integral and fitted at its ends with substantially perpendicular brackets that can be 6884 joined together in the assembled position, preferably by screws or a clamp. The integral design of the base structure of this embodiment simplifies further the assembly of the device of the invention. By connecting the brackets to each other, the device of the invention is fastened rapidly and simply to the body to be contacted.

In another embodiment of the invention, elastic sealing lips mutually spaced in the base-body's transverse direction or in its axial direction, run longitudinally or circumferentially on it, and are present at a base structure side facing the body to be contacted when the device is in the assembled position and in this position rest in sealing manner against the outside surface of the body being contacted. In this manner a space subtended in the assembled position of the device between the body to be sealed and the base structure will be sealed against entry of air, dust or moisture. In this embodiment, the elastic material of the sealing lips appropriately is at least in part a thermoplastic elastomer. As a result the same advantages offered by using a thermoplastic elastomer in manufacturing a part of the base structure also are secured in manufacturing the sealing lips.

In the above cited embodiments, the sealing lips may be separate or they may be joined to or integral with the base structure's elastic material. Manufacture of the device of the invention will be 6 6884 further simplified especially when the sealing lips are integral with the base structure.

In one embodiment of the invention the thermoplastic elastomer evinces at least one of the following material properties: the Shore hardness is at least 35 85, preferably about 47-70, in particular about 64 (DIN 53305-A), the compressive "set" is less than about 40 preferably less than about 25 (DIN 53517, temperature: 70 time: 48 h), the tensile strength is atleast about 6 MPa (DIN 53540), the tear elongation is at least about 300% (DIN 53504), the cold standard is less than about 20 0 C, preferably less than about 40 0 C, in particular about 50 0 C (DIN 53445-B), the change in hardness following aging is no more than 3 (DIN 53508, DIN 53505-A), the change in tensile strength following aging is no more than about 15 (DIN 53508, DIN 53504), the change in tear elongation following aging is no more than about 20 (DIN 53508, DIN 53504), the thermoplastic elastomer is ozone-proof and/or uv-proof and/or oil-proof and/or weather-proof.

The above material properties were found advantageous per se, but especially in combination, in particular as regards easy manufacture and long service life of the device of the invention.

6884 In principle the base structure may consist wholly of a thermoplastic elastomer. However, in an advantageous further embodiment of the invention, the base structure is fitted with a support element to which is connected the thermoplastic elastomer. As a result the stability of the device of the invention is increased.

The thermoplastic elastomer can be joined in arbitrary manner to the support element, for instance by casting or injection molding.

However it may also be in the form of an extruded band element.

In a further embodiment of the invention, the support element is a band and runs in the longitudinal direction or in the circumferential direction of the base structure, preferably over its full length and preferably forming the brackets. This embodiment is an especially simple design offering economy.

As regards the embodiments comprising a support element, this element preferably is metallic, in particular of brass and/or of highstrength brass and/or low-alloy copper and/or steel alloyed with chromium-nickel. These materials offer excellent electrical conductivity and therefore will be especially advantageous when the device of the invention is a part of a fixture to set up electrical contact between an electrically conducting part such as a cable or a pipe and the support element is a current transmission element.

The device of the invention is widely applicable, for instance also as anode or cathode protection or to seat sensors entering a pipe 6884 through an aperture and enclosed by an illustratively bush-like device of the invention. In one mode of the embodiments, the device of the invention also may form a seal which seals external surfaces of in particular elongated, illustratively substantially cylindrical bodies such as pipes, hoses and cables.

In another embodiment mode, the device of the invention forms an affixation in particular for an elongated, illustratively substantially cylindrical body such as a pipe or a cable. The device, for instance in the form of a sealed wall-feedthrough, may be used to mechanically affix a pipe, a hose or cable.

The present invention also relates to a device for electrically contacting an electrically conducting part in particular of an elongated, illustratively substantially cylindrical body such as a pipe or cable. It comprises a device of the invention and means to set up an electrically conducting connection between the body to be contacted and a conductor, for instance a grounding cable.

In further embodiments of the device of the invention for setting up an electrical contact, the contact element is metallic, preferably consisting of a flat stranded wire, a flat band, or a braided metal band. Such contacting elements are economical.

In other embodiments comprising the contacting element, the contacting element is connected to the support element. If the support element is metallic, then by setting up an electrically 6884 conducting connection between a conductor such as a grounding cable and the support element which may be externally accessible in the assembled position, an electrical connection can be made to the body to be contacted through the contacting element resting against this body.

In another embodiment of the invention, the base structure comprises at least one electrically conducting contact protrusion resting in the assembled position against the electrically conducting part of the body to be contacted and thereby forming the contacting means. This embodiment does not require a separate contact element and as a result the design of the device of the invention is further simplified.

In the above embodiment, the or all contact protrusions are appropriately present at the support element. If for instance this element is made of sheetmetal, the contact protrusions may consist of curvatures or beads impressed in the sheetmetal.

Depending on particular requirements, the thermoplastic elastomer may be selected within wide limits. For instance the thermoplastic elastomer may be a thermoplastic polyurethane (TPE-U), and/or a styrene block copolymer (TE-S) and/or a thermoplastic polyolefin elastomer (TPE-O) and/or a thermoplastic copolyester (TPE-E) and/or a polyether-polyamide block copolymer and/or an elastomer alloy of at 6884 least one thermoplastic elastomer, as provided for in the various embodiment modes.

Claim 23 defines a method for manufacturing a composite product composed of at least one thermoplastic elastomer and/or at least one support material as claimed in claims 1 through 22. Further implementations of this method are claimed in claims 24 and Brief Description of the Drawings The invention is elucidated below in relation to the attached drawings of illustrative embodiments.

Fig. 1 is a perspective view of a first embodiment of the device of the invention, Fig. 2 is an axial cross-section on an enlarged scale of a part of an electrical cable electrically contacted by the device of Fig. 1, Fig. 3 is a schematic perspective of the cable contacted by the device of Fig. 1, Fig. 4 is a view similar to Fig. 2 of a second embodiment of a device of the invention, Fig. 5 is a schematic elevation of the radial inside surface of the device of the invention of Fig. 1, Fig. 6 is a schematic, radial section of the device of Fig. 4 in the assembled position, 6884 Fig. 7 is a schematic perspective view of a third illustrative embodiment of a device of the invention, Fig. 8 is a view similar to Fig. 7 of a fourth embodiment of the device of the invention, Fig. 9 is the same view as in Fig. 7 of the device of Fig. 8, one end being connected by a bracket, Fig. 10 is the same view as in Fig. 8 of the device of Fig. 8, the ends being connected by the two brackets.

Detailed Description of the Preferred Embodiments Identical or corresponding components are denoted by the same references in the Figures of the drawing.

Fig. 1 shows a first embodiment of a device of the invention in the form of a device 2 to contact in electrically conducting manner an electrically conducting part of in particular an elongated, illustratively cylindrical body such as a pipe or a cable. The device 2 comprises a flexible base structure 4 made of a thermoplastic elastomer into which is imbedded a metallic band-shaped support element 6 The thermoplastic elastomer in this embodiment mode evinces the following material properties: the shore hardness A is about 64 (DIN 53505-A), 6884 the compression "set" is less than 25 approximately (DIN 53517 at 70 0 C, time 48 h), the tensile strength is higher than about 6 Mpa (DIN 53504), the tear elongation is more than about 300 (DIN 53504), the cold standard is less than about 40 0 C (DIN 53445-B), the change in hardness following aging is no higher than about 3 (DIN 53445-B), the change in tensile strength following aging is no higher than about 15% (DIN 53508, DIN 53504), the change in tear elongation following aging is no higher than about 20 (DIN 53508, DIN 53504), the thermoplastic elastomer is ozone-proof; uv proof and oilproof.

The base structure 4 is fitted at its ends with brackets 8, the support element 6 running in the circumferential direction of the base structure 4 as far as the region of the brackets. Through-holes are present in the bracket 8 to pass omitted screws when in the assembly position of the device 2 of Fig. i, said screws being screwed into threaded boreholes 14 formed in the bracket 10 in such manner that by tightening the screws, the brackets 8, 10 can be tightened to each other and as a result of which the base structure 4 of the device 2 encloses the body to be contacted. The screws in the threaded boreholes 14 making contact with the metallic support element 6, they 6884 may be used to set up an electrically conducting connection of the support element and thereby of the body to be contacted with a connecting cable, omitted from Fig. 1, for instance a grounding cable.

Furthermore the device 2 is fitted at the inside surface 16 of the base structure with mutually axially offset sealing lips 18, running in the circumferential direction of the base structure 4 and which, in the assembly position of the device 2, rest in sealing manner against the external surface of the body to be contacted. In the embodiment shown, additional sealing lips 22, 24 are present in addition to the sealing lips 18, 20 and axially externally to latter.

In the shown embodiment, the sealing lips 18, 20 and also the additional sealing lips 22, 24 are made of the same thermoplastic elastomer as the base structure 4 and are integral with it.

Illustratively the device of the invention 2 can be manufactured by imbedding the support element 6 while also forming the sealing lips 18, 20 and the additional sealing lips 22, 24 shall be imbedded by extrusion coating in the thermoplastic elastomer. However the base structure 4 together with the sealing lips 18-24 also may consist of extruded band material. Fig. 2 shows that the thermoplastic elastomer leaves free a contact zone 28 on the inside surface 26 of the support element 6.

As regards the assembly position shown in Fig. 2, the device 2 together with the sealing lips 18, 20 as well as the additional 6884 sealing lips 22, 24 rests against an external surface 30 of a substantially cylindrical body, in this instance against the outside surface of a cable 32. An electrically conducting zone 34 has been formed at the outside surface 30 of the cable 32 by removing the insulator of the outer conductor. A contact element 36 to set up an electrically conducting connection between the outside surface 30 and the inside surface 26 of the support element 6 is mounted between the electrically conducting zone 34 and the inside surface 26 of the support element 6, this element in this instance being made of elastic graphite. However the contact element 36 also may be metallic, for instance being a metallic strand or braid.

When the bracket 8 is tightened to the bracket 10 by the screws omitted from Fig. 1, the base structure 4 encloses the outside surface of the cable 32, the sealing lips 18, 20 and the additional sealing lips 22, 24 being compressed thereby and coming to rest in sealing manner against the external surface 30 of the cable 32, the space formed between the inside surface of the base structure and the t outside surface 30 of the cable 32 thereby being sealed by said lips against penetration by dust and moisture. Moreover seals may be provided at the brackets 8, 10 to seal the space subtended by the inside surface 16 of the base structure 4 and the outside surface of the cable 32 in the circumferential direction of the base structure.

6884 In addition, when the brackets 8, 10 are tightened, the contact element 36 will be compressed between the inside surface 26 of the support element 6 and the electrically conducting zone 34 at the outside surface 30 of the cable 32 to create thereby an electrically conducting connection between the outer conductor of the cable 32 and the support element 6. In this manner an electrically conducting connection can be set up by means of the screws passing through the support element 6 and the threaded boreholes 14 between the outer conductor of the cable 32 and an external conductor such as a grounding cable.

Fig. 2 shows that the sealing lips 18, 20 are resp. mounted in such manner relative to the associated longitudinal edges 38, 40 of the support element 6 of the base structure 4 that the sealing lips 18, 20 each run axially from a zone inside the associated longitudinal edge 38, 40 to approximately the vicinity of the associated longitudinal edge 38, 40. In this manner the sealing lips are reliably compressed equally when the device 2 of the invention is i mounted to the cable 32 between the support element 6 and the outside surface 30 of the cable 32, rather than being individually forced out externally in the axial direction. Because the elastic material of the base structure together with the sealing lips 18, 20 and the additional sealing lips 22, 24 are made of a thermoplastic elastomer, the manufacture of the device 2 of the invention will be economical.

6884 The thermoplastic elastomer is easy to process and hence produced economically, for instance by injection molding, casting or extrusion.

Vulcanization is not needed. Consequently the production cycles are shortened in manufacture which thus becomes more economical.

Because of the above discussed materialproperties of the thermoplastic elastomer, the device of the invention 2 is rugged, of long service life, offers aging stability and can withstand high mechanical stresses. Furthermore it can be used over wide range of temperatures.

The device 2 shown in Figs. 1 and 2 also can be used as a seal, for instance to seal an electrically conducting contact or the like at an outer surface in particular of a substantially cylindrical body against penetration by moisture or dust into the contacting zone. In such an application the contacting means, in particular the metal contact element 36 and where called for also the support element 6, will be unnecessary.

Fig. 3 shows the device 2 of Figs. 1 and 2 in the assembled position. It is clear that the base structure 4 in this assembly position rests against the cable 32 and encloses it like a bush.

Fig. 4 shows a second embodiment of a device of the invention to set up an electrically conducting contact and differing from the embodiment of Fig. 1 in that the contact element 36 has been replaced by contact protrusions of which only one is shown and is denoted by 38 6884 in Fig. 4. The contact protrusion 38 is formed by a substantially cross-sectionally convex bulge (relative to the cable) and when seen in topview presents a substantially circular cross-sectional contour.

Fig. 5 is an elevation of the radial inside surface of the base structure 4 and shows that the contact protrusion 38 and a further contract protrusion 40 each are formed in topview by a circular salient in the support element 6.

Fig. 6 is a schematic radial section of the device 2 in the assembly position and shows, besides the contact protrusions 38, 40, a further contact protrusion 42, and that the contact protrusions 38, 42 are substantially equidistant in the circumferential direction of the base structure 4.

Fig. 7 is a third embodiment of a device 2 of the invention essentially differing from the embodiment of Fig. 1 in that the brackets 8, 10 are provided with separate end parts 44, 46 shown raised off the brackets 8, 10 in Fig. 7. The end parts 44, 46 in this embodiment are molded parts consisting wholly of a thermoplastic elastomer. In this embodiment the ends 44, 46 are over-injected on the plane surfaces 48, 50 of the brackets 8, 10 which in the assembly position face each other. However they also may be connected in arbitrary manner to the brackets 8, 10. In the assembly position, the ends 44, 46 comprise sealing surfaces 52, 54 which rest against each other in sealing manner.

6884 Fig. 8 shows a fourth embodiment of a device of the invention 2 which differs from the embodiment of Fig. 1 in that the support element 6 is fitted with circumferential beads 56, 58 which are apart in the axial direction of the base structure 4 and which receive separate, thermoplastic-elastomer sealing-lip parts 60, 62. The sealing-lip parts 60, 62 may be bonded into the beads 56, 58 or kept in them by clamping or in positively locked manner and comprise each two sealing lips 64, 66 and 68, 70 which are axially apart.

Fig. 9 shows the device 2 of Fig. 8, the bracket 8 connecting the end part 46. To preclude leaks in a region where the sealing-lip parts 60, 62 adjoin the sealing surface 54, the end part 46 may be fitted with recesses complementary with the free ends of the adjoining sealing-lip parts 60, 62 and receiving the latter. However the end part 46 also may be joined to the ends of the sealing-lip parts 60, 62 for instance by over-injecting.

Fig. 10 shows the device of Fig. 9, the end 44 being connected to the support element 6 in a manner corresponding to the end part 46.

In the embodiment of Figs. 8 through 10, the sealing-lip parts 60, 62 preferably are made of the same thermoplastic elastomer as the end parts 44, 46.

Furthermore the sealing-lip parts 60, 62 also may be integral with the end parts 44, 46 and/or the end parts 44, 46 illustratively may be injected over the support element 6.

6884 While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.

Claims (20)

1. A device for contacting in particular elongated, illustratively substantially cylindrical bodies such as cables or pipes/tubes, comprising a base structure which in the assembly position rests against the body to be contacted and composed at least in part of an elastic material, characterized in that the elastic material consists at least in part of at least one thermoplastic elastomer (TPE).

2. A device as claimed in claim i, characterized in that the base structure is flexible.

3. A device as claimed in claim i, characterized in that the base structure is designed to enclose the body to be contacted preferably annularly or like a bush when in the assembly position.

4. A device as claimed in claim i, characterized in that the base structure is designed as a clamp which can be tightened around the body to be contacted. A device as claimed in claim 1, characterized in that the base structure is integral and comprises substantially orthogonal 21 6884 brackets 10) at its free ends, these brackets being connectable preferably using screws or clamps.

6. A device as claimed in claim 1, characterized in that the device comprises elastic sealing lips (64, 66; 68, 70) which are mutually apart in the longitudinal direction or in the circumferential direction of the base structure and which, in the assembly position, are mounted on one side of the base structure facing the body to be contacted and in that position rest in sealing manner against the body to be contacted.

7. A device as claimed in claim 6, characterized in that the elastic material of the sealing lips (64, 66; 68, 70) at least in part consists of a thermoplastic elastomer.

8. A device as claimed in claim 6 and characterized in that the sealing lips (64, 66; 68, 70) are separate, or are connected to I- the elastic material of the base structure or are integral with this material.

9. A device as claimed in claim 1, characterized in that the thermoplastic elastomer evinces at least one of the following material properties: ".RA 0u 6884 the shore hardness is about 35 to 85, preferably about 47 to 70, in particular about 64 (DIN 53505-A), the compression "set" is less than about 40 preferably less than about 25 (DIN 53517 at 70 0 C, time 48 h), the tensile strength is higher than about 6 Mpa (DIN 53540), the tear elongation is higher than about 300 (DIN53504), the cold standard is lower than about -20°C, preferably lower than about -40°C, in particular about -50 0 C (DIN 53445-B), the change in hardness following aging does not exceed about 3 (DIN 53508, DIN 53505-A), the change in tensile strength following aging is no larger than about 15% (DIN 53508, DIN 53504), the change in tear elongation following aging is no higher than about 20 (DIN 53508, DIN 53504), the thermoplastic elastomer is ozone-proof, and/or uv proof, and/or oil-proof, and/or weather-proof. A device as claimed in claim 1 and wherein, the base structure comprising a support element to which is connected the thermoplastic elastomer.

11. A device as claimed in claim 10, characterized in that the 6884 support element is in the form of a band and runs in the longitudinal or the circumferential direction of the base structure preferably over its full length and preferably forms the brackets

12. A device as claimed in claim 11, characterized in that the support element is made of a metal, in particular brass or high- strength brass and/or low-alloy copper and/or steel alloyed with chromium-nickel.

13. A device as claimed in claim 1, characterized in that the device forms a seal sealing the outside surface of in particular elongated, illustratively substantially cylindrical bodies, for instance pipes or cables (32)

14. A device as claimed in claim 1, characterized in that this device forms a holding means for in particular an elongated, illustratively substantially cylindrical body, for instance a pipe or a cable (32) A device to contact in electrically conducting manner an electrically conducting part (34) of in particular an elongated, illustratively substantially cylindrical body, for instance a pipe or 6884 a cable characterized in that the device contacting in electrically conducting manner comprises a device as claimed in one of the above claims and contacting means to set up an electrically conducting connection between the body to be contacted and a conductor, for instance a grounding cable.

16. A device as claimed in claim 15, characterized in that the contacting means comprise a contact element (36) mounted at a side of the base structure which in the assembly position faces the body to be contacted.

17. A device as claimed in claim 16, characterized in the contact element (36) is metallic.

18. A device as claimed in claim 17, characterized in that the contacting element (36) is a flat strand, a flat band or a braided band.

19. A device as claimed in claim 16, characterized in that the contact element (36) is connected to the support element A device as claimed in claim 15 characterized in that the 25 6884 base structure comprises at least one contact protrusion (38, 42) made of an electrically conducting material and which in the assembly position rests against the electrically conducting part of the body to be contacted and thereby forms the contact means.

21. A device as claimed in claim 20, characterized in that the or each contact protrusion (38, 40, 42) is formed on the support element.

22. A device as claimed in claim 1, characterized in that the thermoplastic elastomer is a thermoplastic polyurethane (TPE-U) and/or a styrene block copolymer (TPE-S) and/or a thermoplastic polyolefin elastomer (TPE-O) and/or a polyether polyamide block copolymer and/or a thermoplastic copolyester (TPE-E) and/or an elastomer alloy of at least one thermoplastic elastomer.

23. A method for manufacturing a composite product composed of at least one thermoplastic elastomer and/or at least one support material, in particular a device as claimed in claim 1, wherein the thermoplastic element is connected by fusion or over-injection with the support material.

24. Method as claimed in claim 23, characterized in that the 26 6884 fusion is implemented by mirror welding. Method as claimed in claim 23, characterized in that the support material is metallic and/or a plastic, in particular nylon.