Note: Descriptions are shown in the official language in which they were submitted.
105377~
This invention relates to electrical clamping
terminals.
Screw-clamping terminals comprising a sleeve to
receive a conductor, and a clamping screw extending transversely
to the conductor are well known. Howe~er, these have the
disadvantage that access to the terminal from at ;east two
different sides is necessary, for insertion of the conductor
and operation of the clamping screw.
~ Clamping terminals ha~e also been proposed in
which it is possible to insert the conductor substantially
parallel to the clamping screw, for example in British ~atent
Specification No.1 382 750. In the latter, a clamping member
has an aperture traversed by the shank of the clamping screw
so that the head of the screw causes pivoting of the clamping
member. A disadvantage of this is that assembly of the terminal
is relatively tedious because the clamping member has to be
fitted onto ~he clamping screw, the provision of a hole in
. the clamping member represents an additional manufacturing
step which increases cost, and the hole weakens the clamping
member. Other known terminals in which a conductor can be
inserted substantially parallelto the clamping screw use
wedges, cams and other relatively complex constructions to
provide the clamping action.
An object of the invention is to provide an
electrical clamping terminal for receiving a conductor
substantially parallel to the clamping screw, having a cheaper7
--1 .
~05377~
-, simple and robust construction.
: The present invention resides in an electrical
.' terminal comprising a ~T-section body of bent sheet metal and
having a transverse member extending transversely to the
. 5 limbs and base of the U, a clamping screw threaded in the
, said transverse member and extending generally parallel to
'j the base of the U and between the limbs thereof, and a generally
~ L,shaped pi~otable clamping member located in the body between
:~ the limbs thereof and having a first arm laterally spaced
~`, 10 from a clamping surface in the body generally parallel to the
J screw and a second arm disposed to be engaged by the screw tip,~i the body providing access for insertion of a conductor between
~ the first arm and the clamping surface whereby on tightening
i~ of the clamping screw the inserted conductor can be clamped
l 15 in the body.
-1 ~he invention also resides in a cl~m~ing device
', for connecting external stripped and/or insulated electrical
~J conductors parallel to the axis of the terminal screw and
¦ comprising a terminal member which is bent from a sneet metal
¦ 20 strip into a U-shaped closed member and a thrust-transmitting
element w.hich can be adjusted by means of the terminal screw,
-characterizedin that the thrust-transmitting element is
constructed as a loose clamping bar, which is merely guided by
the terminal member and has one end on which a terminal screw
,ii
acts, o~eration of which screw causes the clamping bar to be
displaced in the direction of the conductor entry passage
, .
, -2-
.j .
. , ,_ _, . ,, .. , . . , . ,, ,_, _ _ . , . ._, _., _ __ _ _ _ _ _ __ _ __
~053771
about a pivoting point which is provided in a recess of
the terminal member or loosely on any desired support point
of the interior of the terminal member, so that the inserted
conductor is clamped between the inner edge of the terminal
member and the clamping bar.
Since there is no longer any need to provide a
screw-receiving hole in the clamping member, the manufacture
of the latter can be carried out by a simple stamping and/or
pressing operation, its strength is not impaired, and assembly
~0 of the terminal is simplified.
The transverse member may be integral with at
least one limb of the U, or may be a non-rotatable nut
mounted between the limbs of the U.
The first arm of the clamping member may be loosely
pi~otable on the transverse member. Alternatively, an
: intermediate region of the cla~ping member may rest loosely
: on and pivot on a fur~her transverse member. In a further
possible construction, the first arm of the clamping member
~ay have a lateral pivot projection which rests loosely against
an edge of a limb of the U.
A fixed conductor may be provided between the
first arm of the clamping member and the clamping surface.
In this case, only the fixed conductor need be of highly
conductive metal, and the rest of the terminal can be made for
example of sheet or strip steel.
The first arm of the clamping member, and/or the
1053771
fixed conductor if provided~may have at least one sha~p point
or edge for penetrating insulation of an inserted insulated
conductor, and/or a rough surface (pr~vided for example by
milling or by ribs or grooves) for gripping an inserted
~ 5 conductor.
: Four embodiments of the invention are sho~l in
the accompanying drawings, in which:-
Figures 1 to 3 are respectively sectional views
j of three terminals embodying the invention;
i 10 Figure 4 is a perspective view o~ the body of
! such a terminal;~
Figure 5 is a v~ew corresponding to Figure 1, of
J a fourth terminal embodying the invention; and
Figure 6 is an exploded perspective view o~ the
! 15 terminal shown in Figure 5.
The terminal shown in Figure 1 has a clamping
body 1 formed of bent sheet metal strip, substantially identical
~, to that shown in Figures 1 and 6 of 3ritish Pate~t SpecifiGation
~o.1 382 750. This body is of U-shape~ cross section comprising
two spaced parallel side walls 10, 11 forming the limbs of the
i U, interconnecting by a third wall 12 forming the base of the U,
J and a pair of overlapping transverse members 13, 14 respectively
-~ integral with the side walls, 10, 11, perpe~dicular to the
i walls 10, 11 and 12 and containing a screw-threaded aperture
15 in which a clamping screw 7 is threaded. Alternatively, the
transverse members 13, 14 may be replaced by a separate plate
~.
105377~
secured to the side walls. These members terminate short of
the wall 12 to form an aperture 17 for insertion of an electrical
conductor 6 parallel to the wall 12 and the screw 7. A fixed
conductor strip 4 is placed against the inner surface of the
wall 12 and extends to a further terminal, for example a
further clamping terminal, or a solder tag, plug pin or wire-
wrap pin integral with the conductor 4 itself.
The edge of the side wall 10 adjacent to the
transverse member 13 contains a notch 3.
Between the side walls 10,11 is an L,shaped clamping
member 2 comprising a first arm 18 extending between and
generally parallel 2 the screw 7 and wall 12 and spaced from
~ the latter, and a second arm 19 ad~acent to the tip of the
- clamping screw 7. The end of the first arm 18 has a lateral
pivot projection 5 which rests on the edge of the wall 10 in
the recess or notch 3, so that the clamping member can pivot
about this projection. This clamping member can be made by a
; simple stamping and bending operation, as can the body of the
terminal.
In use, the conductor 6 is inserted into the
terminal body between the conductor 4 and the limb 18 of the
clamping member 2, and the screw 7 is tightened so as to
pivot the clamping member about its projection 5 so that the
clamping member moves towards the wall 12, thereby clamping
the conductor 6.
I~ desired, the end of the arm 18 of the clamping
` ~0~;~77~
member may be T-shaped, to provide a pair of oppositely
directed pi~ot projections ~or engaging respective recesses
in both side walls of the body.
The terminal shown in Figure 2 has a substantially
identical body 1 but in this case the limb 18 of the clamping
member 2 is loosely pivoted on the transverse member 13 and
is retained by an integral hook 20 fitting an aperture 21
~ in the transverse member 14, to permit the pivoting of the
j clamping member 2 on rotation of the clamping screw 7. The,
, 10 clamping member shown in Figure 2 is manufactured by a simple
'~ stamping or puncning operation.
I The body of the terminal shown in Figure 3 is
', identical to that of Figure 1, but in this case the clamping
member 2 is a bent metal bar, again provided with a lateral
pivot projection 5 on the end of its arm 1~. A clamping member
is provided with a double bend for added strength.
Figures 5 and 6 show a terminal in which the body
1 is again of U-shaped cross section but in this case the
transverse member in which the clamping screw 7 is threaded
is a nut 8 located in apertures 9 of transverse lugs 22, 23
integral with the side walls 10, 11. Thus the nut can neither
rotate nor move axially in the body. A fixed conductor 4
extends across the upper edges of the lugs 22, 23 and has a
, bent end portion 24 which rests against the surface of the lug
-'~ 25 22 facing the wall 12 of the body. The clamping screw 7,~', extends through a hole 25 in the conductor 4, holding the latter
, . ,
i -6-
1053771
captive.
A further transverse member 26 integral with the
side wall 11 (or with the wall 10 or 12) extends perpendicular
to the walls 10, 11 and 12 and faces the conductor entry 17.
The clamping member 2 is a simple L,shaped bent
metal bar of which the intermediate region of its angle 27
rests loosely on the transverse member 26. In use, the
conductor 6 is inserted between the arm 18 of the clamping
member and the conductor 4, and the screw 7 is tightened so
that the arm 18 clamps the conductor 6.
The terminals illustrated will in practice be
disposed in insulating housings for example of the well known
clip-on type for mounting on flanged channel-section rails.
Such an insulating body may contain a pair of
terminals, for example a pair of the terminals shown in
- Figures 5 and 6 interconnected by a common fixed conductor 4,
or a pair of terminals of which the bodies are formed from a
single piece of metal sheet or strip to provide two (or more)
conductor entry apertures or clamping positions. The terminals
may be provided with means for making cross-connections to
adjacent terminals of a row of terminals, for example as in the
s aforementioned clip-on terminal blocks.
