NO743007L - - Google Patents

Description

Device for strain relief of plastic stoppers

The invention relates to a device for strain relief

of plastic plugs that are spray-stopped on electrical wires.

Especially in connection with electric heaters,

i.e., such as generate heat in one way or another, rubber-insulated cables are prescribed in certain places. You then have the possibility-

called spraying rubber stoppers on such lines, which, however, is expensive and cumbersome, as the stopper body must first be vulcanized in the spray stopper machine. On the other hand, it is permitted to produce stoppers for such cables from plastic material and spray-stop these onto the rubber-insulated cables. The manufacturing process will of course be significantly cheaper and simpler, but there follows the disadvantage that the plastic material in the stopper does not connect with

the cable's rubber insulation, so that the contact points inside the plug body are not strain-relieved.

The invention is based on the task of providing a simple and inexpensive way to relieve the strain of the contact points in plastic plugs that are spray-stopped on rubber-insulated cables, and this task is solved according to the invention by arranging in the area of the plug body on the cable a fixed plastic ring,

if the bore at least in one place has a smaller diameter than the cable cross-section. The advantage of this is that the plastic material in the plug body will wrap around the plastic ring that is fixed to the rubber-insulated cable, so that all tensile effects are absorbed by; this apparently as a knot-like plastic ring.

An illustrative example of the object of the invention can be seen from the drawing, whose fig. 1 shows a longitudinal section of a spray-stop stopper on a line, and fig. 2 and 3 show two possible versions of the plastic ring on a larger scale.

In fig. 1 shows a rubber-insulated cable 1 with conductors 2

and 3 connected by plug pins 4 and 5 attached to a plastic bridge 6. The plug body is spray-stopped around the end of the cable 1 and consists, for example, of a flexible polyvinyl chloride. Within the end of the cable 1, a plastic ring 8 is arranged in the area of the stbpsellegeniet 7 which is attached to the cable. As can be seen from fig. 1, the plastic material in the plug body is placed behind this ring, so that the cable is prevented from being pulled out of the plug seal.

The plastic ring 8 is according to fig. 2 and 3 designed

in such a way that its bore is narrowed at least in one place in relation to the cable diameter. According to fig. 2, the bore is narrowed at the front end of the ring 8 and is thus pressed into the cable insulation and thus sits immovably on the cable in the face of normal tensile stresses.

In another embodiment of the ring 8, the narrowing can

of the bore have the form of an internal thread 9, see fig. 3, so that the attachment to the cable is simplified, as it now only has to be screwed on.

Claims (2)

1. Device for strain relief of plastic plugs that are spray-stopped•on electrical wires, characterized in that in the area of the plug body (7) on the cable (1) a fixed plastic ring (B) is arranged, the hole of which is drilled in at least one place has a smaller diameter than the tile half-section. 2. Device according to claim 1, characterized in that the plastic ring (8) has a bore that is narrowed at one end. 3", Device according to claim 1, characterized in that the plastic ring (8) is designed with an internal thread (9).