STRAIN RELIEF PART FOR THE MECHANICAL UNION BETWEEN A CONNECTOR AND A CABLE, ASSEMBLY AND LUMINAIRE COMPRISING SUCH PART

Abstract

 Strain relief part (P) for the mechanical union between a connector (1) provided with a retaining projection (11) and a cable (2) partially inserted into the connector (1), which comprises a first cover (P1) and a second cover (P2) and locking means (P11, P21), such that the part (P) can be closed to house inside one end of the connector (1) and one end portion of the cable (2), wherein one of the covers comprises a retaining surface (S, S1, S2) complementary to the retaining projection (11) of the connector (1) the covers comprise pressure elements (TP1, TP2) so that when the first cover (P1) and the second cover (P2) are closed on the end of the connector (1) the retaining projection (11) of the connector (1) faces the retaining surface (S, S1, S2) and the pressure elements (TP1, TP2) press the cable (2). The invention also relates to an assembly comprising a connector (1) a cable (2) and a strain relief part (P) and to a luminaire (L) comprising one or more LED light sources (LED) and a driver (D) provided with a primary side (D1) and a secondary side (D2).

Description

TECHNICAL FIELD

[0001] This invention is related to the field of strain relief parts, destined to mechanically connect a cable and a connector, such that the longitudinal forces arising between the connector and the cable are diverted to the strain relief connector instead of being transmitted to the electrical connection.

STATE OF THE ART

[0002] Known are the strain relief parts for the mechanical union between a connector and a cable partially inserted into the connector.

[0003] Some known parts are provided with a first cover and a second cover, a hinge and locking means between the first and second covers, such that the part can be closed to house inside one end of the connector and one end portion of the cable.

[0004] Therefore, the technical problem posed by the fact that the electrical connection can itself be subjected to high mechanical forces is already known, and is solved by the strain relief part just disclosed. This can happen, for example, when, after making an electrical connection between a lamp and a driver, the lamp that was just connected is hanging from the cable, when it is a ceiling lamp.

[0005] The known strain reliefs are designed to connect cables with a greater section than those used to connect devices that operate in direct current, such as LED lamps.

[0006] However, current standards such as EN60598-1-2015 or the corresponding IEC 60598 already require that devices that work with direct current and small voltages must be connected with strain reliefs.

[0007] The majority of known strain reliefs are large and bulky and are intended for joining high-section cables. Typical dimensions are of the order of 5 cm long, 2 cm wide and 1 cm height.

[0008] However, the inventors of the present invention have found that even reducing their dimensions for a dimensional adaptation, these strain reliefs do not work well when applied to cables of very small section.

DESCRIPTION OF THE INVENTION

[0009] For overcoming the mentioned drawbacks and achieve the aforementioned aims, the present invention proposes a strain relief part for the mechanical union between a connector provided with a retaining projection and a cable partially inserted into the connector, the part being provided with a first cover and a second cover, and locking means between the first and second covers, such that the part can be closed to house inside one end of the connector and one end portion of the cable, the first and second covers each comprising a first end such that these first ends define therebetween an opening for the end of the connector and each comprising a second end such that these second ends define therebetween an opening for the end portion of the cable, wherein at least the first cover or the second cover comprises a retaining surface complementary to the retaining projection of the connector and both the first cover and the second cover comprise respective pressure elements, the surface being arranged on the side of the first ends and the pressure elements arranged on the side of the second ends, so that when the first cover and the second cover are closed on the end of the connector and are blocked by the locking means, the retaining projection of the connector faces the retaining surface and the pressure elements press the cable.

[0010] With this strain relief the shortcomings of the state of the art are solved. In particular, the inventors have found that it adapts particularly well to cables of reduced dimension.

[0011] It is a part that can be easily installed thanks to its structure and thanks to the pressure surfaces and to take advantage of a retention protrusion of the connector they allow resisting tensile forces of at least 5 kg. The dimensions of the strain relief are the following: its length in the direction is comprised between 1,4 and 2 cm, its width in the transversal direction is comprised between 0,6 cm and 1,5 and its height is comprised between 0,5 and 1,2.

[0012] In some embodiments, the part is made of a single piece, wherein the first cover and the second cover can be closed on the end of the connector by rotation around the hinge, such that the strain relief can be made in a single piece. In a preferred embodiment, the hinge and the locking means are on opposite sides of the first and second cover.

[0013] In some embodiments the cable is provided with one conductor or two conductors and at least one sheath, either for each conductor or for both, such that the pressure elements press the sheath or the sheaths.

[0014] In some embodiments the strain relief part according to any of the embodiments disclosed above, includes a retaining surface on both covers.

[0015] In some embodiments the retaining surface or the retaining surfaces are formed in an opening of the covers or as a protrusion of the covers. In other embodiments the retaining surface is a through hole in one of the covers.

[0016] In some embodiments the locking means are constituted by one or more hooks arranged in one of the covers and complementary openings in the other cover.

[0017] It is emphasized that this feature of the invention, like all the others, is moldable in a single piece.

[0018] In some embodiments the openings are constituted by a lateral projection provided with through openings.

[0019] In some embodiments the lateral projection is discontinuous. So that facilitates the blocking and avoids unnecessary stresses in the locking tabs.

[0020] In some embodiments the pressure elements are arranged facing each other or are arranged offset with respect to the longitudinal direction of the cable.

[0021] The variant in which the pressure elements are in offset is especially effective for use cables of small section, because these can take bends of reduced radius without breaking, and its interaction with the elements of pressure allows to obtain direct capacity of resistance of forces of longitudinal traction according to the direction of the cable. In other words, when pressed by the elements in offset, the cable makes two curves, so that a force by longitudinal support is added to the friction force obtained by the pressure elements.

[0022] In some embodiments the pressure elements are tabs contained in a plane perpendicular to the longitudinal direction of the cables, and wherein at least one of the tabs is tilted towards the first end.

[0023] In this way, at least one of the pressure elements acts as an anti-return element. The more tensile force applied, the stronger the force applied by the pressure element, as it will rotate slightly backward, reducing the passage section and therefore increasing its pressure on the cable.

[0024] In some embodiments the pressure elements have a rough or flat profile on their contact surface with the cable and are rounded at the ends, so that they do not have sharp edges. The objective of this feature is to avoid cutting the sheath or cable sheaths in the event that very high forces are applied.

[0025] In some embodiments the part is a single piece made of plastic material.

[0026] In some embodiments the part is a moulded part or a 3D printed part and preferably wherein the covers are printed forming a relative opening of 90 °.

[0027] It is known that 3D printers are increasingly efficient and now they can print fully functional pieces. The part of the invention can be molded, but in case of small series, for example specially adapted for a specific connector, manufacturing them with a 3D printer is also cost effective.

[0028] In some embodiments one of the covers comprises on its surface oriented towards the cable, cable positioning arms.

[0029] The invention also relates to an assembly comprising a connector a cable and a strain relief part according to any of the preceding claims.

[0030] Finally, the invention also relates to a luminaire comprising one or more LED light sources and a driver provided with a primary side and a secondary side, the LED or LEDs being connected to the driver's secondary side, wherein the connection between the LED or LEDs and the driver secondary side comprise a connector, a first cable between the driver and the connector, a second cable between the connector and the LED, both cables being mechanically joined to the connector by a part according to any of the inventive variants disclosed above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To complete the description and in order to provide a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate embodiments of the invention, which should not be interpreted as restricting the scope of the invention, but just as an example of how the invention can be carried out. The drawings comprise the following figures:

Figure 1 shows in perspective a part according to the invention, from its external side.

Figure 2 shows in perspective a part according to the invention, from its internal side.

Figures 3 and 4 are analogous to Figures 1 and 2, but according to another embodiment.

Figure 5 schematically illustrates an embodiment of the invention.

Figures 6 to 8 illustrate the sequence of mechanical connection between cable and connector by using the part of Figures 3 and 4.

Figures 9 to 11 illustrate the sequence of mechanical connection between cable and connector by using the part of Figures 1 and 2.

Figure 12 schematically shows a luminaire provided with a driver in which the parts according to the invention are used.

DESCRIPTION OF A WAY OF CARRYING OUT THE INVENTION

[0032] As shown schematically in figure 5, the present invention relates to a strain relief part P conceived for the mechanical union between a connector 1 provided with a retaining projection 11 and a cable 2 partially inserted into the connector 1. The cable shown is provided with a conductor 21 surrounded by a sleeve or sheath 22. Therefore, the inventive part P is destined to transmit forces between the cable 2 and the connector 1. The invention can be also applied in the case of two conductors, each surrounded by a sheath, and a further common sheath surrounding both sheaths, or two conductors surrounded by two sheaths.

[0033] For such purpose, the part P is provided with a first cover P1 and a second cover P2, a hinge P3 and locking means P11, P21 between the first P1 and second P2 covers, such that the part P can be closed to house inside one end of the connector 1 and one end portion of the cable 2, as shown in the mounting sequences shown in figures 6 to 11.

[0034] As shown in figures 1 to 4, the first P1 and second P2 covers each comprise a first end P1U, P2U such that these first ends define therebetween an opening for the end of the connector 1. The connector 1 has two ends, as shown in figure 6, a widened end, for example destined to be connected to a complementary connector, and a narrower end, destined to house an end portion of the cable 2. In the example shown, the narrower end is that provided with the retaining projection 11.

[0035] Thus, each cover P1 and P2 comprise a second end P1D, P2D defining therebetween an opening for the end portion of the cable 2.

[0036] In the example shown in figures 3 to 8, the second cover P2 comprises a retaining surface S, S2 complementary to the retaining projection 11 of the connector 1 and arranged on the side of the first ends P1U, P2U, which will cooperate to transmit longitudinal forces which arise when pulling the cable 2.

[0037] The first cover P1 and the second cover P2 comprise respective pressure elements TP1, TP2, arranged on the side of the second ends P1D, P2D, on the side of the cable inlet.

[0038] In this way, when the first cover P1 and the second cover P2 are closed on the end of the connector 1 by rotation around the hinge P3 and are blocked by the locking means P11, P21, the retaining projection 11 of the connector 1 faces the retaining surface S, S1, S2 and the pressure elements TP1, TP2 press the cable 2, as shown in the final configurations of figures 8 and 11.

[0039] As shown in figure 2, the locking means P11, P21 are constituted by two hooks arranged in the first cover P1 and complementary openings in the other cover P2. These openings are in turn constituted by a lateral projection P21 provided with through openings. As shown, the lateral projection P21 is discontinuous, which allows for an easier closing operation.

[0040] As shown in figure 12, the invention is specially fit to be applied to a Luminaire L comprising one or more LED light sources LED and a driver D provided with a primary side D1 and a secondary side D2.

[0041] The LEDs are connected to the driver's secondary side D2, and the connection between the LEDs and the driver secondary side comprise a connector 1, a first cable 2 between the driver and the connector 1, a second cable 2 between the connector 1 and the LED, both cables 2 and the connector 1 being mechanically joined by a part P according to the embodiments disclosed above.

[0042] As already stated above, the objective of the invention was to develop a strain relief part of reduced dimensions, in particular designed to join cables of reduced diameter, since the known strain relief parts are designed for larger diameter cables.

[0043] The characteristics that define the connector according to the present invention are especially compatible with a small size part, as for example with the following dimensions:

• the length of the strain relief part in the direction is preferably comprised between 1,4 and 2 cm, its width in the transversal direction is comprised between 0,6 cm and 1,5 and its height is comprised between 0,5 and 1,2.

[0044] In particular, the inventors have found that a connector with the features of the invention and having dimensions near 1,55 cm x 0,7 cm x 0,7 cm allow resisting tensile forces of at least 5kg. In this embodiment, the width (0,7 cm) only encompasses the body, excluding the hinge and the locking means.

[0045] In this text, the term "comprises" and its derivations (such as "comprising", etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements.

[0046] The invention is obviously not limited to the specific embodiments described herein, but also encompasses any variations that may be considered by any person skilled in the art within the general scope of the invention as defined in the claims.

Claims

1. Strain relief part (P) for the mechanical union between a connector (1) provided with a retaining projection (11) and a cable (2) partially inserted into the connector (1), the part (P) being provided with a first cover (P1) and a second cover (P2) and locking means (P11, P21) between the first (P1) and second (P2) covers, such that the part (P) can be closed to house inside one end of the connector (1) and one end portion of the cable (2), the first (P1) and second (P2) covers each comprising a first end (P1U, P2U) such that these first ends define therebetween an opening for the end of the connector (1) and each comprising a second end (P1D, P2D) such that these second ends define therebetween an opening for the end portion of the cable (2), characterized in that at least the first cover (P1) or the second cover (P2) comprises a retaining surface (S, S1, S2) complementary to the retaining projection (11) of the connector (1) and both the first cover (P1) and the second cover (P2) comprise respective pressure elements (TP1, TP2), the surface (S, S1, S2) being arranged on the side of the first ends (P1U, P2U) and the pressure elements (TP1, TP2) arranged on the side of the second ends (P1D, P2D), so that when the first cover (P1) and the second cover (P2) are closed on the end of the connector (1) and are blocked by the locking means (P11, P21), the retaining projection (11) of the connector (1) faces the retaining surface (S, S1, S2) and the pressure elements (TP1, TP2) press the cable (2).

2. Strain relief according to claim 1, which comprises a hinge (P3), such that the first cover (P1) and the second cover (P2) can be closed on the end of the connector (1) by rotation around the hinge (P3).

3. Strain relief according to any of the preceding claims, wherein the cable (2) is provided with at least a conductor (21) and at least one sheath (22), such that the pressure elements (TP1, TP2) press the sheath (22).

4. Strain relief part (P) according to any of the preceding claims, which includes a retaining (S1, S2) surface on both covers (P1, P2).

5. Strain relief part (P) according to any of the preceding claims, wherein the retaining surface or the retaining surfaces (S, S1, S2) are formed in an opening of the covers (P1, P2) or as a protrusion of the covers (P1, P2).

6. Strain relief part (P) according to any of the preceding claims, wherein the locking means (P11, P21) are constituted by one or more hooks arranged in one of the covers (P1, P2) and complementary openings in the other cover (P1, P2).

7. Strain relief part (P) according to claim 5, wherein the openings are constituted by a lateral projection (P21) provided with through openings, wherein the lateral projection (P21) is preferably discontinuous.

8. Strain relief part (P) according to any of the preceding claims, wherein the pressure elements (TP1, TP2) are arranged facing each other or are arranged offset with respect to the longitudinal direction of the cable.

9. Strain relief part (P) according to any of the preceding claims, wherein the pressure elements (TP1, TP2) are tabs contained in a plane perpendicular to the longitudinal direction of the cables (2), and wherein at least one of the tabs is tilted towards the first end (P1U, P2U).

10. Strain relief part (P) according to any of the preceding claims, wherein the pressure elements (TP1, TP2) have a rough or flat profile on their contact surface with the cable and are rounded at the ends, so that they do not have sharp edges.

11. Strain relief part (P) according to any of the preceding claims, wherein the part (P) is a single piece made of plastic material, preferably a moulded part or a 3D printed part and more preferably wherein the covers (P1, P2) are printed forming a relative opening of 90 °.

12. Strain relief part (P) according to any of the preceding claims, wherein its length in the direction is comprised between 1,4 and 2 cm, its width in the transversal direction is comprised between 0,6 cm and 1,5 and its height is comprised between 0,5 and 1,2 cm.

13. Strain relief part (P) according to any of the preceding claims, wherein one of the covers (P1, P2) comprises on its surface oriented towards the cable, cable positioning arms.

14. Assembly comprising a connector (1) a cable (2) and a strain relief part (P) according to any of the preceding claims.

15. Luminaire (L) comprising one or more LED light sources (LED) and a driver (D) provided with a primary side (D1) and a secondary side (D2), the LED or LEDs being connected to the driver's secondary side (D2), characterized in that the connection between the LED or LEDs and the driver secondary side comprise a connector (1), a first cable (2) between the driver and the connector (1), a second cable (2) between the connector (1) and the LED, both cables (2) being mechanically joined to the connector (1) by a part (P) according to any of the claims 1 to 13.

Drawing