MAGNETIC ELECTRICAL PLUG INTERFACE

Abstract

A magnetic electrical plug interface for charging a transport refrigeration unit, TRU. The magnetic electrical plug interface includes a first electrical connector and a second electrical connector. The first electrical connector includes: a socket having a closed end and an open end; a first magnetic body including a first electrical contact, the first magnetic body is slidable in the socket; a resilient biasing element configured to bias the first magnetic body towards the closed end of the socket; and a second electrical contact fixed towards the open end of the socket. The second electrical connector includes: a second magnetic body including a third electrical contact. In an unplugged configuration in which the first electrical connector is disengaged from the second electrical connector, the resilient biasing element is configured to maintain a separation between the first electrical contact and the second electrical contact.

Claims

1. A magnetic electrical plug interface (100; 300) for charging a transport refrigeration unit, TRU, the magnetic electrical plug interface (100; 300) comprising: a first electrical connector (1) comprising: a socket (10) having a closed end and an open end; a first magnetic body (13) comprising a first electrical contact (14), wherein the first magnetic body (13) is slidable in the socket (10); a resilient biasing element (12a; 12b; 12c) configured to bias the first magnetic body (13) towards the closed end of the socket (10); and a second electrical contact (15) fixed towards the open end of the socket (10); a second electrical connector (2) comprising: a second magnetic body (23) comprising a third electrical contact (29); wherein, in an unplugged configuration in which the first electrical connector (1) is disengaged from the second electrical connector (2), the resilient biasing element (12a; 12b; 12c) is configured to maintain a separation between the first electrical contact (14) and the second electrical contact (15); and wherein, in a plugged configuration in which the first electrical connector (1) is engaged to the second electrical connector (2), at least one of the first magnetic body (13) and the second magnetic body (23) is configured to be magnetically attracted to the other of the first magnetic body (13) and the second magnetic body (23), such that the first electrical contact (14) engages the second electrical contact (15).

2. A magnetic electrical plug interface (100; 300) as claimed in claim 1, comprising a first electrical cable (11) extending through the closed end of the socket (10) and connected to the first electrical contact (14).

3. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein a first end of the resilient biasing element (12a) is fixed towards the closed end of the socket (10); and wherein a second end of the resilient biasing element (12a) is attached to the first magnetic body (13); wherein the first magnetic body (13) is configured to stretch the resilient biasing element (12a) when actuated such that a restoring force is generated by the resilient biasing element (12a).

4. A magnetic electrical plug interface (100; 300) as claimed in claim 2, wherein a second of the resilient biasing element (12b) is fixed towards the open end of the socket (10); and wherein a first end of the resilient biasing element (12b) is fixed to the first electrical cable (11); wherein the first magnetic body (13) is configured to pull the first electrical cable (11) towards the open end when actuated and thereby compress the resilient biasing element (12b), such that a restoring force is generated by the resilient biasing element (12b).

5. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein the resilient biasing element is a helical spring (12a; 12b).

6. A magnetic electrical plug interface (100; 300) as claimed in claim 2, wherein the resilient biasing element is a spring-loaded winding mechanism (12c) located in the socket (10); wherein the first electrical cable (11) is at least partially wound around the spring-loading winding mechanism (12c); and wherein the first magnetic body (13) is configured to pull the electrical cable (11) towards the open end when actuated and thereby rotate the spring-loaded winding mechanism (12c), such that a restoring force is generated by the spring-loaded winding mechanism (12c).

7. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein, in the plugged configuration, the first electrical connector (1) is configured to readily disengage from the second electrical connector (2) when pulled in a disengaging direction to the second electrical connector (2).

8. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein the socket (10) and the second electrical contact (15) encapsulate the first electrical contact (14).

9. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein the socket (10) comprises a recess defined between the second electrical contact (15) and the open end.

10. A magnetic electrical plug interface (100; 300) as claimed in claim 8, wherein the second electrical connector (2) comprises a cap (20) defining a hollow in which the second magnetic body (23) is located; wherein the third electrical contact (29) protrudes from the hollow; and wherein the recess is configured to receive the third electrical contact (29).

11. A magnetic electrical plug interface (100; 300) as claimed in claim 9, wherein, in the plugged configuration, the socket (10) and the cap (20) encapsulate each of the first electrical contact (14), the second electrical contact (15) and the third electrical contact (29).

12. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein, in the plugged configuration, the second electrical contact (15) is adjacent to and in electrical communication with each of the first electrical contact (14) and the third electrical contact (29).

13. A magnetic electrical plug interface (100; 300) as claimed in claim 1, wherein each of the first magnetic body (13) and the second magnetic body (23) are formed of a non-conductive material; and wherein each of the first electrical contact (14) and the third electrical contact (29) comprise a conductive material located on the first magnetic body (13) and the second magnetic body (29) respectively.

14. A magnetic electrical plug interface (300) as claimed in claim 1, comprising: an outlet (301) comprising a plurality of first electrical connectors (1), wherein each of the first electrical connectors (1) are located within a first housing; and an inlet (302) comprising a plurality of second electrical connectors (2), wherein each of second electrical connectors (2) are located within a second housing.

15. A magnetic electrical plug interface (300) as claimed in claim 11, wherein the outlet (301) comprises an earth socket (310); and wherein the inlet comprises an earth pin (329); wherein the earth pin (329) protrudes a greater distance from the second housing than any of the third electrical contacts (29).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Certain exemplary embodiments of the invention are described below by way of example only and with reference to the accompanying drawings in which:

[0072] FIGS. 1A and 1B show a first magnetic electrical plug interface before and during engagement respectively;

[0073] FIGS. 2A and 2B show a second magnetic electrical plug interface before and during engagement respectively;

[0074] FIGS. 3A and 3B show a third magnetic electrical plug interface before and during engagement respectively; and

[0075] FIG. 4 shows a three-phase magnetic electrical plug interface before engagement.

DETAILED DESCRIPTION OF THE INVENTION

[0076] FIG. 1A shows a magnetic electrical plug interface 100 in an unplugged configuration. The magnetic electrical plug interface 100 comprises a first electrical connector 1 and a second electrical connector 2. The first electrical connector 1 is connected to a power source (not shown), such as a charging station or an electrical grid, and the second electrical connector is connected to an energy storage device of a transport refrigeration unit (TRU) (not shown).

[0077] The first electrical connector 1 comprises a socket 10 through which a first electrical cable 11 passes. The first electrical cable 11 is in electrical communication with the power source. Within the socket 10 is also a resilient biasing element 12, a first magnetic body 13, a first electrical contact 14 mounted on the first magnetic body 13, and a second electrical contact 15. The first magnetic body 13 and the first electrical contact 14 are slidably mounted within the socket 10, the positions of which are maintained by the resilient biasing element 12 to be not in contact with, or spaced apart from, the second electrical contact 15, in the unplugged configuration. Whenever the resilient biasing element 12 experiences an extension due to sliding of the first magnetic body 13 and the first electrical contact 14, a spring/elastic force is generated which is arranged to restore the separation between the first electrical contact 14 and the second electrical contact 15.

[0078] The socket 10 comprises an end wall 17 located at a first end of the socket 10, with the second electrical contact 15 located towards a second end of the socket 10 opposite the first end. The second electrical contact 15 is, in the present embodiment, located within the socket 10 such that a recess is defined between the second end of the socket 10 and the second electrical contact 15. The width/diameter of the recess is much greater than the depth of the recess. The second end of the socket 10 is an open end, such that the second electrical contact 15 is accessible, or exposed, within the socket 10. The first end of the socket 10 is hence comparatively a closed end. The first electrical contact 14 is enclosed within the socket 10, located between the end wall 17 and the second electrical contact 15, such that the first electrical contact 14 is not accessible or exposed.

[0079] The first electrical cable 11 passes through an opening in the end wall 17, and is connected to the first electrical contact 14 such that the first electrical contact 14 is in electrical communication with the power source. The first electrical cable 11 passes through a bore of the first magnetic body 13, such that it can terminate at the first electrical contact 14 without obstructing a face of the first electrical contact 14. In the present embodiment, only a sheath of the first electrical cable 11, the first electrical contact 14 and the second electrical contact 15 are made of electrically conductive material. The first electrical cable 11 is preferably encased in an electrically insulating material, and the socket 10 is also preferably made of an insulating material such that handling of the first electrical connector 1 is made safer.

[0080] The second electrical connector 2 comprises a cap 20 defining a hollow in which a second magnetic body 23 is housed. A third electrical contact 29 is mounted to a face of the second magnetic body 23, facing outwards from the hollow of the cap 20. A second electrical cable 21 passes through a back wall 27 of the cap 20, through a bore in the second magnetic body 23 and terminates at, and in electrical communication with, the third electrical contact 29. The second electrical cable 21 is connected to the TRU, such that electrical communication between the third electrical contact 29 and the power source of the TRU is facilitated.

[0081] Similarly to the first electrical connector 1, only a sheath of the second electrical cable 21 and the third electrical contact 29 are made of electrically conductive material. The second electrical cable 21 is preferably encases in an insulating material, and the cap 20 is also preferably made of an insulating material, such that handling of the second electrical connector 2 is made safer.

[0082] The third electrical contact 29 protrudes outwardly from the cap 20, and hence defines a stunted pin or male portion which is complementary to the recess, or female portion, of the socket 10. The second electrical connector 2 is configured to engage the first electrical connector 1 via a mating engagement of the stunted pin and the recess of the respective connectors 2, 1. In this respect the first electrical connector 1 may be considered an electrical outlet, and the second electrical connector 2 may be considered an electrical plug configured to be received by the electrical outlet.

[0083] As shown in FIG. 1A, the resilient biasing member of the present embodiment is a helical spring 12a, and is configured to maintain a separation between the first electrical contact 14 and the second electrical contact 15, when the first electrical connector 1 is in the unplugged configuration (i.e. disengaged from the second electrical connector 2).

[0084] A first end of the helical spring 12a is fixed towards the first (i.e. closed) end of the socket 10, and a second end of the helical spring 12a is fixed to the first magnetic body 13. The first end of the helical spring 12a is more specifically fixed to a backboard 16, which is located between the end wall 17 and the second electrical contact 15, within the socket 10. The first electrical cable 11 passes through an opening in the backboard 16, and longitudinally through the helical spring 12a to prevent tangling or clamping of the first electrical cable 11 within the helical spring 12a.

[0085] In the unplugged configuration there is an air gap, or a separation, between the first electrical contact 14 and the second electrical contact 15. The separation between the first electrical contact and the second electrical contact 15 is maintained by the helical spring 12a. That is, the spring 12a is configured to provide a restoring force such that, when the spring 12a experiences an extension which in the present arrangement is a stretching, the first electrical contact 14 is motivated towards the closed end of the socket 10 and away from the second electrical contact 15. As such the only exposed electrical contact, i.e. the second electrical contact 15, of the first electrical connector 1 is not in electrical communication with the power source in the unplugged configuration; and the first electrical connector is therefore made safe to handle in the unplugged configuration due to the action of the resilient biasing element 12.

[0086] A chamber 18 is defined within the socket 10, located between the end wall 17 and the backboard 16. The first electrical cable 11 is configured to gather, or bunch, within the chamber 18 in the unplugged configuration such that a region of slack is provided. The region of slack of the first electrical cable 11 is configured to become taut as the first electrical contact 14 moves. The region of slack of the first electrical cable 11 hence facilitates free movement of the first electrical contact 14, to which the first electrical cable 11 is connected. FIG. 1B, comparatively, shows that the slack in the first electrical cable 11 is taken up when the first magnetic body 13 and the first electrical contact 14 slide towards, and into contact with, the second electrical contact 15.

[0087] FIG. 1B shows the magnetic electrical plug interface 100 in a plugged configuration, in which the first electrical connector 1 is engaged to the second electrical connector 2. In the plugged configuration, the second electrical contact 15 is in contact with both the first electrical contact 14 and the third electrical contact 29. In this way, an electrical connection is provided between the first electrical cable 11 and the second electrical cable 21; and hence also between the power source and the TRU.

[0088] In the unplugged configuration, the spring 12a maintains a separation between the first electrical contact 14 and the second electrical contact 15 owing to a restoring force generated by the helical spring 12a, whenever it is extended. However, in the plugged configuration, the second magnetic body 23 is moved into close enough proximity with the first magnetic body 13 such that a magnetic attraction between the first magnetic body 13 and the second magnetic body 23 motivates the first electrical contact 14 into contact with the second electrical contact 15. Thus, in the plugged configuration, a magnetic attraction between the first magnetic body 13 and the second magnetic body 23 generates a sufficient force to extend the spring 12a and move the first electrical contact 14 into engagement with the second electrical contact 15. In this way, an electrical flow path between the power source and the TRU is completed.

[0089] In the plugged configuration the socket 10 and the cap 20 are configured to fully encapsulate the second electrical contact 15 and the third electrical contact 29. As such, all electrical contacts 15, 29 which are otherwise exposed in the unplugged configuration are surrounded by insulating material. Thus, as the electrical flow path through the second electrical contact 15 and the third electrical contact 29 is only completed when the second electrical connector 2 engages the first electrical connector 1, a risk of electrical shock to a user of the magnetic plug interface 100 is mitigated.

[0090] The magnetic electrical plug interface 100 also facilitates easy engagement and/or disengagement of the first electrical connector 1 from the second electrical connector 2 as necessary. For example, attraction between the first magnetic body 13 and the second magnetic body 23 as the connectors 1, 2 are moved into engagement may assist a user of the magnetic electrical plug interface 100 in moving the connectors 1, 2 into the plugged configuration. Further, as the connectors 1, 2 may be maintained in the plugged configuration owing to the magnetic attraction between the first magnetic body 13 and the second magnetic body 23, there is no need for a locking mechanism or other securement feature which needs to be engaged when connecting the connectors 1, 2 together. This may facilitate ease of engaging and disengaging the connectors 1, 2 from one another.

[0091] Additionally, as the recess located at the open end of the socket 10 is shallow (i.e. its depth is significantly smaller than its width or diameter), a longitudinal distance required to remove the second electrical connector 2 from the first electrical connector 1, before it can move laterally, is reduced.

[0092] In other words, owing to a minimised or reduced surface area of any lateral contact faces between the first electrical connector 1 and the second electrical connector 2, the mating engagement of the first electrical connector 1 and the second electrical connector 2 does not greatly resist lateral forces in such a way that could damage the magnetic electrical plug interface 100. This facilitates disengagement of the second electrical connector 2 from the first electrical connector 1 when either connector 1, 2 is pulled in a direction which causes disengagement to the other.

[0093] The magnetic electrical plug interface 100 can hence readily disengage, or move from the plugged configuration to the unplugged configuration, such as when a vehicle comprising the TRU may drive away without unplugging the connectors 1, 2 from one another. It will be appreciated that, owing to the restoring force of the helical spring 12a, when the connectors 1, 2 are disengaged the separation between the first electrical contact 14 and the second electrical contact 15 will be restored. The first electrical connector 1 is therefore capable of being readily disengaged from the second electrical connector 2; and when doing so readily returns to the unplugged configuration in which the first electrical connector 1 is safe for a user to handle.

[0094] FIG. 2A shows an alternative arrangement for the first electrical connector 1 in the unplugged configuration. The outer structure of the first electrical connector 1, and its engagement with the second electrical connector 2 remain the same as described above, and hence will not be repeated. However, an alternative internal arrangement of the resilient biasing element 12 is provided.

[0095] As seen in FIG. 2A, there is provided a resilient biasing element 12 which is a helical spring 12b, the backboard 16, and the first magnetic body 13 to which the first electrical contact 14 is mounted. However, in this configuration, the helical spring 12b protrudes from the backboard 16 towards the end wall 17 at the closed end of the socket 10.

[0096] A first end of the helical spring 12b located towards the closed end of the socket 10 is connected to the first electrical cable 12b, either directly or via an intermediate component. A second end of the helical spring 12b located towards the open end of the socket 10 is fixed to the backboard 16. The backboard 16 hence separates the helical spring 12b from the first magnetic body 13. The helical spring 12b and the first magnetic body 13, however, are in communication with one another via the electrical cable 11. Thus, when the first magnetic body 13 moves towards the second electrical contact 15 at the open end of the socket 10, the electrical cable 11 pulls the first end of the helical spring 12b towards the backboard 16. Compression of the helical spring 12b against the backboard 16 generates a restoring force, which motivates the first end of the helical spring 12b away from the backboard 16. Motion of the first end of the helical spring 12b pulls the electrical cable 11, and hence the first magnetic body 13, away from the open end of the socket 10. In this manner, the separation or air gap between the first electrical contact 14 and the second electrical contact 15 is maintained in the unplugged configuration.

[0097] FIG. 2B shows the first electrical connector 1 having the alternative arrangement for the resilient biasing element 12, and the second electrical connector 2 in the plugged configuration. Magnetic attraction between the first magnetic body 13 and the second magnetic body 23 causes the first electrical contact 14 to move into contact with the second electrical contact 15, and hence complete the electric flow path between the power source and the TRU. The magnetic attraction between the first magnetic body 13 and the second magnetic body 23 is therefore greater than a restoring force generated due to compression of the helical spring 12b against the backboard 16. The separation between the first electrical contact 14 and the second electrical contact 15 will therefore only be restored when the second electrical connector 2 is disengaged from the first electrical connector 2.

[0098] FIG. 3A shows a further alternative arrangement for the first electrical connector 1 in the unplugged configuration. The outer structure of the first electrical connector 1, and its engagement with the second electrical connector 2 remain the same as described above, and hence will not be repeated. However, an alternative internal arrangement of the resilient biasing element 12 is provided.

[0099] As seen in FIG. 3A, there is provided a resilient biasing element 12 which is a spring-loaded winding mechanism 12c, a backboard 16 and the first magnetic body 13 to which the first electrical contact 14 is mounted. In this configuration however, the spring-loaded winding mechanism 13 is mounted to the first electrical cable 11, and is pivotally fixed within the socket 10. The spring-loaded winding mechanism 12c is located between the end wall 17 of the socket 10, and the backboard 16 located between the end wall 17 and the first magnetic body 13.

[0100] The first electrical cable 11 is wound around the spring-loaded winding mechanism 12c, and is preferably fixed to the spring-loaded winding mechanism 12c at one point or more. The first electrical cable thus extends from the end wall 17, is wound around the spring-loaded winding mechanism 12c, and extends from the spring-loaded winding mechanism 12c and through the backboard 16, where it then terminates at the first electrical contact 14.

[0101] As the first electrical contact 14 moves towards the second electrical contact 15, the first electrical cable 11 is pulled with the first electrical contact 14. This causes the first electrical cable 11 to unwind from the spring-loaded winding mechanism 12c. The spring-loaded winding mechanism 12c becomes loaded as a result, such that it creates a torque which re-winds the first electrical cable 11. Due to the spring-loaded winding mechanism 12c pulling the first electrical cable 11 back to its wound position, the first electrical contact 14 is urged away from the second electrical contact 15. The separation or air gap between the first electrical contact 14 and the second electrical contact 15 is hence maintained, in the unplugged configuration.

[0102] FIG. 3B shows the first electrical connector having the alternative arrangement for the resilient biasing element 12, and the second electrical connector 2 in the plugged configuration. Magnetic attraction between the first magnetic body 13 and the second magnetic body 23 causes the first electrical contact 14 to move into contact with the second electrical contact, and hence complete the electric flow path between the power source and the TRU. The magnetic attraction between the first magnetic body 13 and the second magnetic body 23 is therefore greater than a restoring force, or torque, generated by the spring-loaded winding mechanism 23 due to winding of the spring-loaded winding mechanism 23. The separation between the first electrical contact 14 and the second electrical contact 15 will therefore only be restored when the second electrical connector 2 is disengaged from the first electrical connector 2.

[0103] FIG. 4 shows a three-phase magnetic electrical plug interface 300 in an unplugged configuration, the three-phase magnetic electrical plug interface 300 comprising an outlet 301 and an inlet 302.

[0104] The outlet 301 comprises a housing which comprises three first electrical connectors 1′, 1″, 1′″. Each of the first electrical connectors 1′, 1″, 1′″ are in electrical communication with the first electrical cable 11 via a respective first electrical cable 11′, 11″, 11′″ carrying a respective phase of current. Each of the first electrical connectors 1′, 1″, 1′″ comprises a structure identical to that as described with respect to FIG. 1A. However, each of the first electrical connectors 1′, 1″, 1′″ could comprise an alternative arrangement to that of FIG. 1A and perform the same function. For example, each of the first electrical connectors 1′, 1″, 1′″ could comprise a resilient biasing element 12′, 12″, 12′″ as described with respect to FIGS. 2A and 3A. The discussion of the structure of each first electrical connector 1′, 1″, 1′″ will therefore not be repeated herein. In the unplugged configuration however, it will be appreciated that each of the resilient biasing elements 12′, 12″, 12′″ of each of the respect first electrical connectors 1′, 1″, 1′″ are configured to maintain a separation, or an air gap, between the first electrical contacts 14′, 14″, 14′″ and the second electrical contacts 15′, 15″, 15′″.

[0105] The inlet 302 comprises a housing which comprises three second electrical connectors 2′, 2″, 2′″. Each of the second electrical connectors 2′, 2″, 2′″ are in electrical communication with the second electrical cable 21 via a respective second electrical cable 21′, 21″, 21′″ carrying a respective phase of current. Each of the second electrical connectors 2′, 2″, 2′″ comprises a structure identical to that as described with respect to FIGS. 1A, 2A and 2A.

[0106] The inlet 302 is configured to engage the outlet 301. When the inlet 302 engages the outlet 301, i.e. in a plugged configuration, magnetic attraction between the first magnetic bodies 13′, 13″, 13′″ of the first electrical connectors 1′, 1″, 1′″ and the second magnetic bodies 23′, 23″, 23′″ of the second electrical connectors 2′, 2″, 2′″ is configured motivate the first electrical contacts 14′, 14″, 14′″ into electrical contact with each of the respective second electrical contacts 15′, 15″, 15′″. In this way, an electrical flow path is provided between a power source connected to the first electrical cable 11, and a TRU connected to the second electrical cable 21.

[0107] The outlet 301 also comprises an earth socket 310. The earth socket 310 is connected to a first earth cable 311, which is connected to an electrical earth, or ground. The earth socket comprises a first earth electrical contact 314, located within the earth socket 310. The first earth electrical contact 314 defines an earth recess 315.

[0108] The inlet 302 comprises an earth pin 329, which is located in an earth cap 320 and is connected to a second earth cable 321. The earth pin 329 protrudes further outwards from the housing of the inlet 302 than any of the third electrical contacts 29′, 29″, 29′″. The earth pin 329 is configured to be received by the earth recess 315, and in doing so provides a completed earth, or ground, connection between itself and the first earth electrical contact 314.

[0109] As the earth pin 320 protrudes further outwards from the housing of the inlet 302 than any of the third electrical contacts 29′, 29″, 29′″, electrical contact is established between the earth pin 329 and the first earth electrical contact 314 before any electrical flow paths can be established between the first electrical connectors 1′, 1″, 1′″ and the second electrical connectors 2′, 2″, 2′″. Completion of an earth electrical flow path, before any other electrical flow path, within the magnetic electrical plug interface 300 may reduce hazards associated with assembling the magnetic electrical plug interface 300. Similarly, as the earth pin 320 is longer than any of the third electrical contacts 29′, 29″, 29′″, the earth electrical flow path is not disconnected until the other electrical flow paths of the magnetic electrical plug interface 300 are disconnected. This may similarly reduce hazards associated with disassembling the magnetic electrical plug interface 300. The earth pin 320 is preferably, however, only just longer than the third electrical contacts 29′, 29″, 29′″, such that its protruding length is still significantly smaller than its width or diameter. Hence disengagement of the inlet 302 from the outlet 301 is still readily possible without damage to the magnetic electrical plug interface 300, including in situations where the outlet 301 and the inlet 301 are pulled apart in partially lateral directions to one another.