Crighton's screw top insulator

CRIGHTON'S INSULATOR

The insulator illustrated in the annexed Fig. 1 is of the form most used by the Postal Telegraph Department. In this the porcelain cap is grooved, and the telegraph wire held by binding wire firmly attached to it and passing around this groove. This binding takes some time, and in some districts the binding wire is rapidly corroded and the attachment destroyed. In the new insulator — the invention of Mr. C. E. Crighton, of Newcastle — the porcelain cap is made in two parts, A and B, as shown in Fig. 2.

The upper part of A is slotted and screwed, as shown by detached sketches, and a strong porcelain cap, B, screws thereon. The telegraph wire W is simply dropped in place, the serrated steel wedge E dropped into the slot, and the cap screwed on. The wire is by this means held so tightly that the ordinary lengths may be suspended by its grip. — Engineer.