Improvements in Connection Fittings for Various Electrical Purposes.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Connection Fittings for Various Electrical Purposes.
I, ROBERT FREDERICK HALL, of Ferndale," Church Road, Moseley, near the
City of Birmingham, Engineer, do hereby declare the nature of this invention
to be as follows:-
:-
This invention relates to the fittings of electrical tumbler and other switches,
cut-outs, fuses, switch boards, meters, measuring instruments, and other electrical
apparatus, and has for object, to provide an improved connection for securing the
cables or wires of such apparatus to their terminal blocks.
This is accomplished by the employment of rotating pius with excentric or
cam-shaped clamping heads, adapted to clamp the end of a cable in position to
its terminal block in such a manner as to ensure a perfect electric connection
with ready attachment and removal, and permit of better insulation being
obtained.
In carrying out my invention as applied to an electric tumbler switch, I take
an earthenware base, fitted with an elevated bearing or bridge bracket having
a cup or socket within which the ball joint of the tumbler arm works as usual
for imparting a rocking movement to the switch arm for taking the latter into
and out of contact with the separated pair of terminal blocks. The inner work-
ing end of the tumbler lever may be fitted with a grooved roller which traverses
the ordinary comb plate fitted to the top side of the switch arm.
The return
fly action of the switch arm is also effected as usual by a spring."
Each terminal block may be fitted within a sunken part of the base, and is
formed with a vertical hole, up which the cable wire is introduced from the
back and terminating in a curved clearance, whilst swivelly or rotatively mounted
upon a part of the said terminal adjacent to the clearance, is an excentric headed
or cam pin. A keep groove or recess adapted to partially receive the end of the
cable may also be formed in the edge of the clearance, and when the cam head
of the pin is partially rotated by a screw driver engaged within a cross nick in
the top side of the same, or otherwise, it makes such a throw as to pinch, clamp
or bind the end of the cable between its own edge, and the keep groove or recess
of the clearance in the terminal block, thus ensuring perfect metallic contact
and a secure connection of the cable to the terminal. As the clamping pin is in
the general vertical line of the terminal instead of the clamping being effected
by a small binding screw projecting from the side, the connection is more
accessible and compact, and permits of better insulation being obtained by the
provision of porcelain walls projecting inwards from the sides of the well in the
base and coming and forming a barrier of insulation between the terminals and
the wood or attachment screws by which the base of the switch is secured in
position.
The clamping edges of the excentric heads of the swivelling pins may either
be plain, or they be serrated or milled to ensure a better grip, whilst instead
of the cam heads acting directly as the clamping medium, they may be made to

page_text: actuate a separate gripping piece, such as a slide having a hole within which the
said head may work.
As applied to fuze boxes, cut outs and the like, the terminal fitting may consist
of a screwed and hollow shank up which the cable passes, terminated by a double
or cross head, one half of which is stepped and is fitted with the swivelling and
excentric headed pin, adapted to clamp the cable between its edge and the shoulder
formed by the stepping, whilst the other part of the head is fitted with the fuze
wire clamping screw.
The application of my invention, as regards the improved connection between
the cable wires and their terminal blocks, to other electrical fittings and apparatus,
differs in no essential respect from its application to tumbler switches as herein
described.
Dated this 17th day of
1000
Improvements in Connection Fittings for Various Electrical Purposes.
I, ROBERT FREDERICK HALL, of "Ferndale," Church Road, Moseley, near the
City of Birmingham, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention relates to the fittings of electrical tumbler and other switches,
cut-outs, fuses, switch boards, meters, measuring instruments, and other electrical
apparatus, and has for its principal object, to provide an improved connection
for securing the cables or wires of such apparatus to their terminal blocks.
This is accomplished by the employment of rotating pins or pivots with
excentric or cam-shaped clamping heads, adapted to grip the end of a cable in
position to its terminal block in such a manner as to ensure a perfect electric
connection and provide a ready means for the attachment and removal of the
cable.
Figure 1 of the accompanying drawing represents a top side plan of a terminal
for tumbler switch and analogous electrical instruments, constructed and arranged
or provided with means for gripping the cable in accordance with one form of
my invention.
Figure 2 is a vertical section of the said terminal, with the gripping pin in
elevation.
These two views, Figures 1 and 2, represent the gripping device in the position
in which it is placed before the clamping of the wire to the terminal is effected.
Figure 3 represents a topside plan and Figure 4 a complete vertical section
of the said connection fitting but showing the wire or cable clamped to the body
of the terminal by the excentric head of the gripping pin.
Figure 5 shows a topside plan of the body part of the terminal, separately.
Figure 6 represents the gripping pin separately in side elevation, partly in
section, and underside plan, and also a complete vertical section of the body of
the terminal, separately.
The same letters of reference indicate corresponding parts in the said Figure 1
to 6.
According to this form of my invention, which is particularly applicable for

page_text: use in connection with tumbler switches and the like, the terminal comprises a
body part a, and a cable-clamping pin b. The said body part consists of a suit-
ably-shaped block of metal a', with a screwed shank a² for the attachment
of the terminal to the insulating base of the switch or analogous instrument,
whilst directed vertically up the said shank and through the body, is a
thoroughfare hole a, up which the cable wire c is introduced from under-
neath. The said hole terminates in a set-down part or clearance, having
a curved side or shoulder as, whilst swivelly or rotatively mounted within the
said clearance, so that its head b, shall lie flush with the top surface of the body
part, is the excentric or cam headed gripping pin b, whose stem 62, lies and turns
within a hole a, in the said body and is there secured by rivetting or expanding
the hollow lower end 63 thereof, or otherwise. A keep groove or recess a¹, adapted
to partially receive the end of the cable to be gripped, is also formed in the
middle of the curved edge or side of the clearance, so that when the cam head
of the pin is partially rotated by a screw driver engaged within a cross neck in
the top side of the same, or otherwise, it makes such a throw as to pinch, clamp
or bind the end of the cable between its own edge and the opposite abutment
provided by the keep groove or recess a³, in the body of the terminal, thus ensuring
metallic contact between the two parts and perfect electrical connection of the
cable to the terminal. As the clamping pin (when in its gripping position) is
in the general vertical line of the terminal and also flush with the body, instead
of the clamping being effected by a small binding screw projecting from the
side of the terminal as usual, the connection is more accessible and compact,
and permits of better insulation being obtained by the provision of porcelain
walls projecting inwards from the side of the well in the switch base and coming
and forming a barrier of insulation between the terminals and the wood or attach-
ment screws by which the base of the switch is secured in position.
The clamping edges of the excentric heads of the swivelling pins may either be
plain, or they be serrated or nulled to ensure a better grip.
Figure 7 represents another form of terminal, particularly applicable for use
in connection with fuze-boxes, cut-outs and analogous electrical fittings. This
view shows a side elevation of the said terminal, without the cable wire, whilst
Figure 8 shows a top-side plan of the same, the head of the clamping pin, in
each view, being shown turned away from the abutment shoulder on the body,
to admit of the cable being introduced up the hollow attachment shank.
This form of terminal fitting consists of a screwed and hollow shank a² up
which the cable passes, terminated by a double or cross head or body part a, one
half of which is stepped at a4 and is fitted with the swivelling and excentric
headed gripping pin 6 whose head 6 is adapted to clamp the cable between its
edge and the shoulder as formed by the stepping, whilst the other half of the head
is fitted with the fuze wire clamping screw d.
Instead of the curved head acting directly as the clamping medium, they may
be made to actuate a separate gripping piece, such as a slide having a hole or
clearance within which the said head may work.
Figure 9 represents a topside plan of a switch or like terminal constructed
according to this modification.
Figure 10 is a longitudinal vertical section of Figure 9 upon the dotted line .r
and Figure 11 represents a transverse vertical section on the dotted line r¹.
a is the body part of the terminal, the attachment shank, a³ the cable hole
therethrough a the clearance in the topside and the abutment end of the said
clearance with a half-round recess, in which the upper end of the cable to be
gripped lies. Located within the said clearance is a gripping slide e, working
between undercut guides and to which a longitudinal sliding movement is imparted
by means of an excentric or cam headed actuating pin b, rotatably mounted upon
the body part of the terminal, with its head 61, working within a transverse
slot el, in the slide. By arranging for the excentric-headed pin to actuate a
gripping slide as described, a clamping device with a greater extent of bearing

page_text: surface against the cable end is obtained whereby a more efficient electrical con
nection between cable and terminal results.
The application of my invention as regards the improved connection between
the cable,wires and their terminal blocks, to other electrical fittings and apparatus,
differs in no essential respect from its application to switches and cut-outs as
herein described.
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:-
:
First In cable connections or terminals for electrical apparatus, the employ-
ment of rotating pins or pivots having excentric gripping heads or cams, and
adapted, when rotated, to clamp the cable to the body of the terminal, substan-
tially as and for the purposes herein described, and also as set forth in the accom-
panying drawings.
Secondly In cable connections or terminals for electric apparatus, the employ-
ment of rotating pins or pivots having excentric cable-gripping heads or cams,
working within a recess or set-down part in the body of the terminal, and with
the cable to be gripped lying within a keep-groove formed in an abutment shoulder
constituting one side of the said recess, substantially as and for the purposes herein
described and also as set forth in the accompanying drawings.
Thirdly In cable connections or terminals for electric apparatus, the employ-
ment of a cable-gripping slide, working within a recess or sinking in the body
of the terminal, which has an abutment between which and the slide, the cable
to be connected is gripped, the said slide is actuated or traversed by the excentric
head or cam of a rotating pin or pivot, substantially as and for the purposes herein
described and also as set forth in Figures 9, 10 and 11 of the accompanying
drawings.
Dated this 6th day of Auril 1900
ROBERT FREDERICK HALL
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.