Tension sensor

A tension sensor (10) for use in an electrified fence wherein the tension sensor (10) includes a housing (12), a first contact (24) which is mounted to the housing and which is configured to be electrically connected to a first wire (64) in the electrified fence, a member (30) which is movable relative to the housing and which includes a contact (56) which is configured to be electrically connected to a second wire (62) in the electrified fence, and a biasing structure which is responsive to a tension level in the wire (62) and which maintains the contacts (24, 56) electrically connected to each other when said tension level is below a first predetermined value, the biasing structure including a first biasing element ((74)-FIG. 2;

• (90)-FIG. 5) which allows the tension level in the wire (62) to be varied up to a limiting point (paragraphs 23, 30, 31) while maintaining the contacts (24, 56) electrically connected to each other and which is characterised in that said limiting point is less than said first predetermined value and in that the biasing structure includes a second biasing element (44) (paragraphs 23, 30, 31) which maintains the contacts (24, 56) electrically connected to each other when said tension level is greater than said limiting point but is less than said first predetermined value and which causes electrical connectivity between the contacts (24, 56) to be broken if said tension level is above said first predetermined value.