According to the Machinery Directive, machines may only be put into operation once comprehensive safety measures have been taken to protect the persons working with these machines. Part of these measures is the protection of hazardous areas at machines, where presence or contact with running machine is to be prevented, because of the risks created by the machine.
To protect persons against risks of this kind, pressure sensitive safety mats are employed. At devices such as machines, machining centres, presses, robot cells, high-shelf warehouses and many others, safety mats immediately switch off the power source, when the mat is stepped on. As long as the person stays on the mat, the machine cannot be set back into operation. Either electrically operating devices to the contact-make principle (two conductive strips or layers are brought together when the safety mat is operated), or opto-electronic systems (a light beam is interrupted) are available on the market. Such configurations need a special evaluator for transforming and processing the output signal.
The HSM Safety Mat uses mechanical positive-break contacts. Therefore, an additional safety control unit is not needed.
As a general rule applies: Machinery and devices presenting dangerous movements must be provided with an emergency stop device. This device is monitored by a suitable safety relay unit.
Our safety mats are built up of mechanically opening break contacts connected in series, in the form of a contact mat (see also our catalogue HSC Safety Edges). Current conducting contact plates and insulating wedge elements are alternately lined up on an expander cord. By pre-tension, the contact plates are pressed together, and the current circuit is made. When stepping on the safety mat, at least one of the contact plate pairs is separated by action of the wedge elements, and the current circuit is broken (see fig. bottom right).
Thus, a transformation of the output signal is not required, since a circuit interruption signal is directly available. This signal is fed to the safety relay unit already needed for the E-stop button. This means: wiring of the contact chain is performed in identical way as of an E-stop button. The number of lined-up contact plates and wedge elements depends on the size of the safety mat.
The contact mat is placed between rubber mats being sealed at their borders by profiles. The surface structure depends on customer's wishes or the requirements in use. The safety mats are manufactured in the sizes as specified by customer (max. & min. sizes see specification). Larger protection areas are achieved by several mats connected together.
A special evaluator is not required, since the contact mat is composed of electro-mechanical break contacts, the signal of which can immediately be further processed. In addition to cost saving, any expensive connection and wiring actions are unnecessary. Valuable space is won on the crowded control panel.
Further, of course, a not existing device cannot go wrong. Moreover, use of a break contact guarantees a high safety level. At singly occurring faults, the system immediately changes to the safe condition: it switches off.
Our safety mat meets the requirements of category 3 of DIN ISO EN 13849-1 - even the sensor part. Double-channel design or redundancy is not necessary for this system, since the failure mode analysis made by BG has shown: a single fault does not lead to a loss of the safety function. This permits a simple construction of the system.
Depending on the specific applications, various conditions may occur. Please inform us, so that we can select the suitable configuration. In order to meet the customized requirements, we use a standard polyurethane as the material for the mat surface. Other materials may also be possible – please contact us. The surface patterns may also vary from application to application. In order to prevent the risk of slipping, chequer patterns are used.
A great variety of applications for the protection of man and machine, e.g.: machines, machining centres, presses, robot cells, high-ceilinged warehouses, material handling, lifting platforms.
The aluminium ramp trim for fixing and protection against tripping is mandatory at step-on sides.