SPRING TERMINAL FOR ELECTRIC WIRES
Year: 1885

page_text: I, BENNETT PELL of No 14 Union Court, Old Broad Street in the City of
London, Electrician, do hereby declare the nature of my invention for "SPRING
TERMINAL FOR ELECTRIC WIRES" and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement :-
When electric wires have to be connected to an instrument or conductor it is
usual to fix them in terminals or posts by screws. This occupies time which it is
often important to save, and the screwing movement sometimes displaces or breaks
the wire; screws, moreover, are liable to become loosened by vibration and if the
wire which the screw is intended to pinch happens to become displaced, the
operator may be misled by thinking he has effected contact when in fact the
contact is insufficient. My invention relates to a construction of terminals or
contact posts in which, instead of a pinching screw, a spring is employed to grip
the wire between contact surfaces, thereby giving certainty of action, ensuring
good contact and preventing loosening by vibration, affording besides facilities for
attaching two or more wires to the same terminal. A terminal arranged according
to my invention with a spring, may be made in many forms, all acting in the same
manner, as I will describe referring to the accompanying drawings which by way
of illustration shew convenient forms for spring terminals. Fig. 1 shows a spring
terminal fixed on a board of wood or other insulating material. The stem A which
is fitted to slide through the boss B is urged by a spring C so as to make its
collar D press against the face of B. On pulling the knob E a wire W can be
inserted between D and B and then, on letting go E, the spring C causes D to grip
the wire firmly between it and the face of B. A wire may also be gripped at the
back of the board as shewn in fig. 2, in which case a washer F fitted to slide along
the stem A is pressed by the spring C so as to grip the wire between it and the
hinder face of B. Several wires may be connected to one terminal as shewn by
fig. 3 where two wires W' and W2 are held by the pressure of the spring, a
washer G being interposed between them. Fig. 4 shews a similar terminal applied
to the top of an insulating post H. It is of advantage to roughen the faces of
the parts D, B, F, between which the wires are held, so as to give a good grip of
the wires.
In the arrangement shewn in fig. 5 a hole a drilled through the stem A, can, by
pressing down the knob E in opposition to the spring C, be brought into coincidence

page_text: with holes bb drilled through the base B, and then, a wire being introduced
through bab, and the knob E being released, the wire will be held by the
spring pressure causing it to make good contact with the metal of the terminal.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
The construction of terminal for electric wires wherein a stem that can be slid
by hand is, when released, urged by a spring so as to grip the wire between
conducting surfaces, substantially as herein described.