DE7514537U - Safety switching device - Google Patents

Description

The innovation relates to a device for actuating a limit switch which interacts with removable or hinged housing parts of machines with internal rotating parts, the actuation taking place with the aid of a switching pin connected to the movable housing parts.

Devices of the type mentioned have the task of interrupting the power supply to the drive motor by actuating a limit switch attached to the machine housing as soon as a removable or hinged housing part, the removal of which makes the parts rotating inside the machine accessible, is removed or folded down. The aim is to ensure that a machine cannot be put into operation when it is open. Examples of such machines are cutting mills, hammer mills, centrifugal mills and the like, in which the grinding elements rotating inside are accessible for repair and cleaning work through hinged housing parts or doors.

The limit switch is actuated directly by the detachable or hinged housing part or by a switching pin permanently connected to it, the switch in the latter case
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Lich is encapsulated in a housing and can only be reached by the switch pin through a corresponding opening in this housing.

However, these known devices no longer meet the applicable safety regulations, according to which the limit switches used for safety on the machine are to be arranged and switched in such a way that they cannot easily be rendered ineffective. The freely attached limit switches can easily be operated by hand; with the encapsulated it is sufficient to use a simple tool, e.g. B. insert a screwdriver into the opening intended for the switch pin and operate the switch.

The innovation eliminates the disadvantages outlined above by means of a device which prevents or at least makes it extremely difficult to actuate the limit switch after the housing parts in question have been removed or folded down. To solve this problem, a device is used with a switch pin connected to the removable or foldable housing parts, in which the switch pin for actuating the limit switch moves a switching ring, which is acted upon by a spring, perpendicular to the switching direction and over the switch button of the limit switch, with a conical taper on the free shaft end of the switching pin engages in a corresponding inner cone in the switching ring.

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Switching ring has been moved far enough in its axial direction. However, this is only possible with the switching pin, since in the proposed design of the switching pin and switching ring there are no contact surfaces for simple tools, so that a screwdriver or other object inserted into the switching ring would slip off the conical inner wall and therefore not be able to do so would be to move the switching ring against the spring pressure so far that the switch could get into its on position.

In the drawing, an embodiment of the proposed device is illustrated schematically, namely shows

Fig. 1 is a section through the device with the machine closed and

FIG. 2 shows a section through the device according to FIG. 1 with the housing cover removed.

In Fig. 1, the switch pin 3 attached to the removable housing cover 1 by means of thread 2, with its conically tapered shaft end 4, has shifted the switch ring 7, which is provided with a corresponding inner cone 5 and guided in the housing 6, axially downward against the action of the spring 8, against the action of the spring 8 the switch button 9 of the limit switch 10 is released, and the limit switch could thus get into its on position.

2 shows the same device with the housing cover 1 removed. After the cover 1 has been removed, the spring 8 has the switching ring 7 upwards and pressed over the switch button 9 and thereby brought the limit switch 10 in the switching direction 11 into its off position, so that the power supply to the drive motor is now interrupted. The switch button 9 of the limit switch 10 can no longer be reached from the outside, actuation is only possible via the switch ring; However, this cannot be pressed down with simple means due to the lack of attack surfaces.

Claims (1)

Device for actuating a limit switch, which interacts with removable or hinged housing parts of machines with internal rotating parts and is actuated with the help of a switch pin, characterized by a switch pin (3) perpendicular to the switching direction (11) and via the switch button (9) of the limit switch (10) displaceable, by a spring (8) acted upon switching ring (7), a conical taper (4) of the free shaft end of the switching pin and a corresponding inner cone (5) in the switching ring.