The word plug comes from to plug in. That’s how easy it usually is to transfer data or power with household appliances or smartphones. Plug in and ready to go. In industry, however, the requirements are much higher and interfaces must be locked in order to ensure proper protection. To be able to connect data, signals and power more quickly and without tools in the future, HARTING is expanding its portfolio of PushPull plugs. Secure connections in a single hand movement.
Interfaces in industrial applications are subject to higher demands. On the one hand, there are external factors such as moisture, dust, noxious gases or vibrations, which can impair or interfere with a connection. On the other hand, it is important to consider handling and ease-of-use by operating personnel. The protection of a connection has the highest priority in order to prevent the worst case scenario of system failure or destruction. Nevertheless, plug operation must be easy and user-friendly. Over the years, different companies have developed such a diverse array of plug types and ensured their continued presence on the market. Plugs are usually sealed and made resistant against dirt or unintentional loosening through vibration by means of a lock. This can be achieved using threaded connections, e.g. by screwing the connector itself, by levers, clips or many other systems. However, this approach often requires tools for assembly, as well as trained installation personnel to estimate the correct fit of the plug.
Since the installation of systems and devices often takes places under far from ideal conditions, i.e. with suitable tools and trained personnel, it was necessary to re-design the interface itself.
The PushPull system has been a successful part of HARTING’s range for some time now. Types 4, 14 and Power L are classic rectangular connectors, which originate from the automotive industry and industrial device cabling. Factors such as durability and fast, but at the same time safe, installation remain in the forefront. Here, the saying “time is money” still applies. PushPull connectors enable all kinds of plug profiles to be securely connected in no time at all. An audible click informs the installer that the connection is now waterproof and closed. No tools, no torques, no special training for personnel.
Various types of plug profile can be accommodated in the universal “containers” of the housing for types 4 and 14. Depending on the application, these can be RJ45, optical fibres in plastic or glass or even USB for the transmission of data. If signals are to be bundled and forwarded, users can choose between 10 and 20-pole plug profiles. However the power supply can be safeguarded using the tool-less interface up to 690 V at 16 A. Together, this provides device manufacturers with all necessary solutions from a single source as part of a uniform and standardized system.
The newest member of the PushPull family came about due to the desires and requirements of the market. The type 4 Mini DisplayPort interface serves the increased use of HMIs in the form of screens and keypads, which are fed video signals. In order to avoid additional conversion of video signals into Ethernet, the DisplayPort interface supports direct forwarding of video signals. Of course, in addition to all the rectangular elements of the PushPull system, it is important not to forget circular plug types.
Rectangular and circular plugs
The M12 is the most common representative in the field of metric circular plugs. It is a classic signal plug with a threaded connection for sensors and actuators. In recent years, this interface has increasingly become the go-to connector for D and X coding for Fast Ethernet and Gigabit Ethernet applications. However, they all feature threaded locking systems, which must be checked with a special torque wrench to ensure the specified IP 65/67 protection class. Obviously assembly takes a longer due to screwing and checking, and the packing density of interfaces on switches is rather limited as a certain amount of space for the tool is always required.
Due to the increasing number of use cases for the M12, HARTING has already been offering it with the PushPull mechanism for a long time and deployed it initially within the railway market. The requirements in the rail sector are among the highest available. If an interface can overcome demands here, it can be used in other application areas without raising concerns. Since feedback from railway manufacturers has been consistently positive and in general the trend in all industrial business sectors is towards increased modularity, HARTING has decided to supplement the PushPull connectors of all series with new types and, in future, to use printed circuit board connections for circular plugs within the PushPull system. This will not inconvenience previous users, because the interfaces are back-compatible and can still be used with conventional M12 screw locks. This means the switch to PushPull can be made gradually. The other alternatives in the M12 range are adapters that convert a standard M12 screw socket to a PushPull socket.
PushPull’s time savings are particularly well received by users and represent an important purchasing criterion when selecting a device. PushPull can be positioned more compactly on housings, because users require less space for each individual interface when connecting without tools. This brings us to the main point and the actual target group: the user, in other words fitters, setters, service personnel or unskilled workers. The fact that tools are no longer required, together with the quick locking system, mean that, in the case of the M12 PushPull for example, assembly times can be reduced by as much as 70 % when compared to M12 screw types. Of course, this is most likely to become a decisive factor when connecting a large number of plugs, however the simplified operation also offers significantly more process reliability when employing unskilled personnel thanks to the system’s clear feedback and user-friendliness.
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