NL2018092B1

NL2018092B1 - Plug assembly for use with refrigerated shipping containers

Info

Publication number: NL2018092B1
Application number: NL2018092A
Authority: NL
Inventors: Maclean Pieter; Pijpers Johan; Van Dijk Rob
Original assignee: Ab Trading & Consultancy B V
Priority date: 2016-12-28
Filing date: 2016-12-28
Publication date: 2018-07-06

Abstract

An electrical plug assembly is disclosed for connecting a cable connected to a refrigerated shipping container or reefer to a power socket, the assembly comprising a housing comprising a side wall defining an interior space, a socket-side opening and a cable side opening; a safety element provided on the housing for unlocking a power socket; and a pin holder arranged partially within the housing and extending through the cable-side opening, the pin holder being arranged to rotate within the housing and comprising at least one electrical ground pin and one or more conductor pins, all facing the socket-side opening; and wherein the pin holder and the housing each comprise at least one rotation path delimiting element for delimiting a path of rotation of the pin holder with respect to the housing, such that the pin holder is rotatable between two or more positions corresponding to different relative positions between the electrical ground pin and the safety element.

Description

Field of the invention

The present invention relates to connectors or plugs, and in particular relates to plugs for connecting refrigerated shipping containers, commonly referred to as reefers, to a power supply socket outlet.

Background art

Shipping containers used for the transport of cargo such as commercial goods are transported throughout the world and may accordingly be temporarily stationed in ports in a multitude of countries.

Many of these shipping containers are refrigerated containers (also referred herein as reefers), used in the transport of cargo such as perishable goods requiring refrigeration. In order to transport and handle refrigerated containers pursuant to health and other safety regulations, the containers must be kept at a minimum refrigeration temperature. To this end, the containers must normally be connected to a power source while stationed at port as well as during transport.

However, power facilities are not uniform across the world, with the consequence that power sockets and plugs differ structurally between regions. Thus, a plug designed for the US container standard is different from a plug designed for the European (EU) container standard.

Further, international standards require that plugs have a safety element, also known as a key, which functions to ensure that only a particular type of plug (i.e., the right plug having a specific arrangement of pins) is connected in a particular socket.

This can be tedious, not least because it requires reefer operators to have both types of plugs available at any one time, but also because it requires time-consuming changing of plugs.

European (EU) and US (US) standard reefer plugs differ only in the position of the earth pin with respect to the safety element. The safety element is typically implemented as a small plastic projection on the exterior of the plug housing. It has become a common practice for operators to cut off the safety element so that a plug of a particular standard may be inserted into a socket conforming to a different standard. This is an undesirable practice as it creates a safety hazard. Moreover, the altered plugs are normally disposed after use because their safety has been compromised or because they are not legally permitted in some ports.

A plug is known from Chinese patent application CN 105140684 which tries to address these problems. However, the known device suffers several drawbacks. An operator needs a tool in order to change the pin arrangement. The tool must be of particular strength, which entails that a tool made of a metallic material will be necessary. This is not only inconvenient, but it is also particularly dangerous as it could lead to an electrical shock to the operator, who may unknowingly be working with a live cable (e.g., if the container is in an improperly insulated container rack). Moreover, the known device comprises many parts, in particular, metallic parts such as springs, which render it more vulnerable and prone to electrical and/or mechanical damage.

Therefore, it is an object of the invention to provide a plug assembly for refrigerated containers, which offers an alternative to the existing plugs and overcomes at least some of their inconveniences.

Summary of the invention

According to the present invention, an electrical plug assembly for connecting a cable connected to a refrigerated shipping (as used herein shipping may refer to any type of sea, land or air transport) container to a power socket is provided, the assembly comprising a housing comprising a side wall defining an interior space, a socket-side opening and a cable-side opening; a safety element provided on the housing for unlocking a power socket; and a pin holder arranged partially within the housing and extending through the cable-side opening, the pin holder being arranged to rotate within the housing comprising at least one electrical ground pin and one or more conductor pins facing the socket-side opening; and wherein the pin holder and the housing each comprise at least one rotation path delimiting element for delimiting a path of rotation of the pin holder with respect to the housing, such that the pin holder is rotatable between two or more positions corresponding to different relative positions between the electrical ground pin and the safety element.

As used herein, the term socket-side opening refers to that opening of the plug assembly housing that faces the socket outlet when connected, while the term cable-side opening refers to the opening of the plug assembly housing which receives the cable connected to the reefer. The plug assembly is arranged to connect to a socket on the socket-side opening and to receive a cable through the cable-side opening for connection to a refrigerated container. The pin holder is arranged for enabling connection of the pins to a cable for connection to a refrigerated container.

The pin holder is arranged to hold one or more pins. The pin holder may comprise one or more connected parts. The pins may have different functions, may comprise at least one earth pin (also commonly referred to as a ground pin), and one or more phase pins (also commonly referred to as pole pins or conductor pins). Further, the pin holder may comprise a neutral pin.

The diameter of each pin will correspond to the diameter of the contact tubes provided in the respective power socket for receiving each respective pin.This prevents incorrect insertion of the plug into the power socket outlet. The diameter of the earth contact pin may be greater than the diameter of the phase (also referred as pole) or neutral contact pins.

The safety element is also commonly referred to as a safety tab or key. Its function is to ensure the proper alignment of the contact pins in the power socket. The safety element must enter the corresponding opening in the power socket (also referred to as the keyway) in order for the power socket to be activated. This ensures no power is provided through an improperly aligned plug.

The pin holder is arranged so that it may be rotated within the housing, the pin holder and the housing each comprising at least one rotation path delimiting element for delimiting a path of rotation of the pin holder with respect to the housing. The pin holder may thus be rotated between two or more positions defined by the rotation path delimiting elements. The rotation path delimiting elements form a rotation path with two or more points corresponding to different relative positions between the electrical ground pin and the safety element.

In a preferable embodiment, the rotation path delimiting elements are arranged so that they define a path having two endpoints each endpoint corresponding to a particular (standard) setting of the pin holder. The setting refers to the angular separation between the earth pin and the safety element, which defines the various standards for plug assemblies. In such embodiment, the pin holder may thus be rotated between two setting positions defined by the rotation path delimiting elements.

Preferably, the two or more positions comprise a first and a second positions corresponding to two or more magnitudes of angular separation between the safety element on the housing and the ground or earth pin. This angular separation is referenced to a central point of the pin arrangement (on a plane perpendicular to the central longitudinal axis of the assembly). In this manner, a refrigerated container operator or any other user is able to easily and conveniently adapt the plug assembly to match the required standard at the point of use of the plug assembly, whether this be a vessel, a port, or any other location. In particular, the operator is able to adapt the plug assembly without the need for any tools. The rotation of the pin holder to a desired setting may be easily effected by holding the housing with one hand, and with the other hand holding the part of the pin holder that extends outside of the housing through the cable-side and rotating the pin holder until the desired setting is attained.

In a preferred embodiment, only two settings or rotation endpoint positions are provided, comprising a first position at 3 o’clock (angular separation of 90 degrees between the ground pin and the safety element) and a second position at 6 o’clock (angular separation of 180 degrees between the ground pin and the safety element). The ground pin orientation terminology arises from the characterization of the front view of the pins (socket-side opening) as the face of a clock. The 3 o’clock configuration is a known EU refrigerated container plug standard, while the 6 o’clock configuration is a known US refrigerated container plug standard. In this manner, a refrigerated container operator or any other user is able to easily and conveniently adapt the plug assembly to match either a US standard container socket or a EU standard container socket at the point of use of the plug assembly, whether this be a transporting vessel, a port, train, or any other location. Further, the operator is able to adapt the plug assembly between the EU and US standards without the need for any tools. The rotation of the pin holder to a desired setting may be easily effected by holding the housing with one hand, and with the other hand holding the part of the pin holder that extends outside of the housing through the cable-side and rotating the pin holder until either the US or the EU setting is attained.

In an embodiment, the housing further comprises an indication window comprising an opening, and the pin holder comprises one or more markings for indicating a position of the ground pin with respect to the safety element, and wherein a marking is viewable through the indication window when the pin holder is set to the position indicated by the respective marking. This easily lets the operator know whether the pin holder is set to the desired setting.

In an embodiment, the housing comprises only two markings, one corresponding to the US standard (such as the abbreviation ‘US’), and one corresponding to the EU standard (such as the abbreviation ‘EU’). This will facilitate use of a plug assembly configured for adaptation to US and EU standards respectively.

In an embodiment, the plug assembly further comprises a locking mechanism arranged to enable and disable rotation of the pin holder with respect to the housing. This locking mechanism may comprise an opening or groove provided on the housing and a corresponding projection provided on the pin holder, or an opening or groove provided on the pin holder and a corresponding projection provided on the housing. In such an embodiment a user presses the opening or groove and projection away from each other in order to unlock the pin holder and enable its rotation with respect to the housing.

In an embodiment, the locking mechanism may comprise a portion of the housing comprising an open circular band having a smaller radius than the maximum radius of the housing, the band having a tab or tongue along an open end and having a projection, the band being biased to press against the pin holder near the cable-side opening, and the projection being arranged to correspond to a respective groove or recess on the pin holder. In such an embodiment a user presses the opening or groove and projection away from each other (e.g. by pulling the tab or tongue with the projectoin away from the pin holder) in order to unlock the pin holder and enable its rotation with respect to the housing. To lock the pin holder, the projection on the tab or tongue is pushed back into the groove or opening in the pin holder.

In an embodiment, the at least one housing rotation path delimiting element comprises one or more projections, and the at least one pin holder rotation path delimiting element comprises one or more grooves or openings, the one or more projections being arranged to extend at least partially into the one or more grooves or openings. In this manner, the opening or groove, in conjunction with the one or more stop elements, defines or delimits the range or length of the path of rotation of the pin holder with respect to the housing.

In an alternative embodiment, the at least one pin holder path delimiting element comprises one or more projections and the at least one housing path delimiting element comprises one or more grooves or openings, the one or more projections being arranged to extend at least partially into the one or more grooves or openings. The delimiting elements on the pin holder and the housing interact to define the rotation path of the pin holder.

In an embodiment, the pin holder and the housing each have a circular cross-section and the one or more grooves or openings extend along at least a part of the circumference of the pin holder or housing.

In an embodiment, the pin holder comprises only three pole pins (also referred to as phase pins), a single electrical earth pin, and no neutral pins, for a total of four pins. These four pins being arranged so as to form the four corners of a square with a separation defining the sides of the diamond or square of between a pin and an adjacent pin is approximately 2 cm.

In an embodiment, the pin arrangement corresponds to the requirements set out in the international standard IEC 60309-1 and -2, and European standard EN 60309-1 and -2, for connectors rated for operating voltages of 380 V, 380-415V, and 440 V.

In an embodiment, the position of the pins with respect to each other remains constant throughout the rotation of the pin holder, and further there is no axial displacement of the pins during rotation of the pin holder. That is, the pins are permanently attached to the pin holder and there is no rotational displacement of a pin with respect to another pin, nor axial displacement of any of the pins. Axial displacement refers herein to displacement parallel to the central longitudinal axis of the housing or pin holder.

In an embodiment, the plug assembly further comprises a locking ring for preventing ingress of solid and liquid matter, or any potential consequence of accidental immersion. The locking ring may comprise a grommet or any other type of locking ring.

In an embodiment, the plug assembly further comprises a lid holding element comprising a projection provided on the housing for holding a socket lid away from the plug assembly. This will prevent any issues that may arise from the plug assembly coming into contact with the power socket lid.

In a further aspect of the invention, a refrigerated shipping container is provided comprising a plug assembly according to any one of the aforementioned embodiments. This advantageously enables easy plugging of the refrigerated shipping contrainer to power sockets conforming to different standards.

The plug assembly housing (or parts thereof) may comprise a material such as polyamide or other engineering plastic, or any combination thereof. These materials provide good resilience and strength characteristics. Alternatively, the housing may be manufactured of a commodity plastic such as polystyrene, polyvinyl chloride (PVC), polypropylene and polyethylene, or any combination thereof. Alternatively, the housing may comprise a combination of engineering plastic materials and commodity plastics materials. The pin holder (or parts thereof) may comprise a material such as polyamide or other engineering plastic, or any combination thereof. These materials provide good resilience and strength characteristics. Alternatively, the pin holder may be manufactured of a commodity plastic such as polystyrene, polyvinyl chloride (PVC), polypropylene and polyethylene, or any combination thereof. Alternatively, the pin holder may comprise a combination of engineering plastic materials and commodity plastics materials.

The pin holder may comprise one or more longitudinal slits so as to increase its flexibility, thus allowing it to compress or yield sufficiently to rotate within the housing. It will be apparent to those skilled in the art that other techniques may be used to impart flexibility to the pin holder. Alternatively or additionally, the pin holder may be substantially rigid, its ability to rotate with respect to the housing being contraled solely via a locking mechanism which enables or disables its rotation within the housing. In the locked position the locking mechanism secures the pin holder with respect to the housing.

The contact pins may be made of any suitable conducting material, such as brass. Additionally, the contact pins may coated to improve desirable properties. For example, the contact pins may be nickel-plated in order to improve the electrical contact, prevent corrosion, and lower the operating temperature.

Short description of drawings

The present invention will be discussed in more detail below, with reference to the attached drawings, in which

Figs. 1a-1d show several views of a schematic depiction of the plug assembly according to the invention.

Figs. 2a-2d show several views of a schematic depiction of a plug assembly housing according to the invention.

Figs. 3a-3d show several views of a schematic depiction of a pin holder according to the invention.

Fig. 4 shows a schematic depiction of a pin arrangement according to the invention.

Description of embodiments

Figs. 1a, 1b, 1c, and 1d show a bird’s eye view, a side view, a front view, and longitudinal or lengthwise cross-section views, respectively, of a plug assembly 100 according to an exemplary embodiment of the invention. It is noted herein that the front view 1c does not show the pins.

The asembly 100 comprises a housing 300 and a pin holder 200 partially arranged within the housing 300. The assembly 100 further comprises a locking ring 102 provided around the housing. The housing 300 also comprises a safety element 104 in the form of a projection extending away from the housing. The safety element 104 is located at the 12 o’clock position (0 degrees). The axis 108 represents the central longitudinal axis of the plug assembly 100, housing 200 and pin holder 300.

Figs. 2a, 2b, 2c, and 2d show a top cross-section view, a side view, a front view, and a side cross-section view, respectively of a housing 200 according to an exemplary embodiment of the invention. The housing 200 defines an interior space 202, a cable-side opening 204 and a socketside opening 206. The housing 300 comprises projections 212a, b which are rotation path delimiting elements for delimiting the path of rotatoin of the pin holder 300 with respect to the housing 300. The housing 200 further comprises a portion or gripping element 208 having a smaller radius than the maximum radius of the housing 200, and which portion comprises a tab or tongue 210. The gripping element is biased to grip the pin holder 300. Additionally, the housing 300 comprises a lid holding element 214 for holding a lid of a power socket away from the plug assembly 100. It is noted herein that the front view 2c does not show the pins.

Figs. 3a, 3b, 3c and 3d show a frist side view, a second side view, a front view, a lengthwise cross-section view, respectively, of a pin holder 300 according to an exemplary embodiment of the invention. The pin holder 300 according to the exemplary embodiment comprises a groove 302, which, in conjunction with the projections 212a, b provided on the housing defines a path of rotation of the pin holder 300 with respect to the housing 200. The pin holder 300 further comprises symmetrically arranged slits 306a, b towards the socket-side opening 206 and symmetrically arranged slits 304a, b near the housing cable-side opening 204. The pin holder 300 further comprises grooves 308 a, b, which in conjuction with the portion or gripping element 208 and the tab or tongue 210 of the housing 200 form a locking mechanism which enables or disables rotation of the pin holder 300 with respect to the housing 200. It is noted herein that the front view 3c does not show the pins.

Fig. 4 shows a schematic front view of a pin arrangement 400 according to the exemplary embodiment. The pin arrangement 400 comprises pins 400a, b, c, and d, each spaced at a distance d with respect to an adjacent pin. A central point 402 of the pin arrangement is the reference for defining the angular separation between a pin and the safety element. The pin 400b is the earth or ground pin, here shown in a 3 o’clock position (EU container standard) with respect to the safety element 104 (depicted schematically with respect to the pin arrangement).

The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.

Claims

Conclusions

Electric plug assembly for connecting a cable connected to a refrigerated transport container to an energy socket, the assembly comprising:

a housing comprising a side wall defining an interior space, a socket side opening and a cable side opening;

a security element provided on the housing for unlocking an energy socket;

and a pin holder which is arranged partially within the housing and extends through the opening on the cable side, the pen holder being arranged to rotate within the housing and comprising at least one electrical earth pin and one or more conductor pins all facing the opening on the socket side; and wherein the pen holder and the housing each include at least one rotation path limiting element for defining a rotation path of the pen holder relative to the housing, such that the pen holder is rotatable between two or more positions corresponding to different relative positions between the electrical earth pin and the security element.

Assembly according to claim 1, wherein the two or more positions comprise first and second positions corresponding to an angle separation of 90 ° (3h) and 180 ° (6h), respectively, between the safety element and the earth spike, the angle separation being determined with reference to a central point of the pin arrangement as projected on a plane perpendicular to the central longitudinal axis of the assembly.

The assembly of any preceding claim, further comprising a locking mechanism adapted to release and block rotation of the pen holder relative to the housing.

The assembly of claim 3, wherein the locking mechanism includes an aperture or groove provided on the housing and a corresponding protrusion provided on the pen holder, or an aperture or groove provided on the pen holder and a corresponding protrusion provided on the housing.

Assembly according to any one of the preceding claims, wherein the at least one rotation path limiting element of the housing comprises one or more protrusions, and the at least one rotation path limiting element of the pen holder comprises one or more grooves or openings, the one or more protrusions being such arranged to extend at least partially into the one or more grooves or openings.

Assembly according to any of the preceding claims, wherein the at least one pad limiting element of the pen holder comprises one or more protrusions and the at least one pad limiting element of the housing comprises one or more grooves or openings, the one or more protrusions being arranged that they extend at least partially into the one or more grooves or openings.

The assembly of claim 6, wherein the pen holder and the housing have a circular cross section and the one or more grooves or openings extend along at least a portion of the circumference of the pen holder or the housing.

An assembly according to any one of the preceding claims, wherein the pen holder comprises a total of four pins containing three pole pins and a single electrical earth pin, the four pins being arranged to form the four corners of a square, the separation between a pen and an adjacent pen is about 2 cm.

Assembly according to any of the preceding claims, wherein the housing further comprises an indication window comprising an opening, and the pin holder comprises one or more markings for indicating a position of the earth pin relative to the safety element, and wherein a mark is visible is through the indicator window when the pen holder is set to the position indicated by the respective mark.

An assembly according to any preceding claim, wherein the positions of the pins relative to each other remain constant along the entire rotation of the pen holder, and no axial displacement of the pins occurs during

5 rotating the pen holder.

The assembly of any of the preceding claims, further comprising a locking ring to prevent ingress of solid and liquid matter.

10

The assembly of any preceding claim, further comprising a lid retaining member that includes a protrusion provided on the housing to keep a receptacle lid away from the plug assembly.

13. Refrigerated transport container comprising a plug assembly according to a

15 of the preceding claims.

Fig. 1A

Fig. 1B

100

Fig. 1D

Fig. 2B

Fig. 2A

212a

Fig. 2C

Fig. 2D

204

Fig. 3A

308b

I

302 308a

Fig. 3B

300

Fig. 3C

300

Fig. 3D

300