U.S. patent number 3,812,449 [Application Number 05/355,455] was granted by the patent office on 1974-05-21 for terminal strip.
This patent grant is currently assigned to Minnesota Mining and Manufacturing Company. Invention is credited to Robert A. Elm.
United States Patent |
3,812,449 |
Elm |
May 21, 1974 |
TERMINAL STRIP
Abstract
A terminal strip including an elongate block of electrically
insulating material divided lengthwise into a plurality of terminal
strip sections. Each terminal strip section has a plurality of wire
receiving bores and a plurality of contact elements having spaced
wire engaging fingers slidably mounted in the block to engage and
interconnect wires in adjacent bores of that section. The sections
may be supported in an elevated position to afford use of a tool,
such as a pliers, to seat a contact element, and the contact
element and the block include means which afford disengaging a
contact element with a pointed tool such as a screwdriver.
Inventors: |
Elm; Robert A. (St. Paul,
MN) |
Assignee: |
Minnesota Mining and Manufacturing
Company (St. Paul, MN)
|
Family
ID: |
23397487 |
Appl.
No.: |
05/355,455 |
Filed: |
April 30, 1973 |
Current U.S.
Class: |
439/402;
439/405 |
Current CPC
Class: |
H01R
4/2429 (20130101); H01R 4/245 (20130101) |
Current International
Class: |
H01R
4/24 (20060101); H01r 009/08 () |
Field of
Search: |
;339/97-99,125 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGlynn; Joseph H.
Attorney, Agent or Firm: Alexander, Sell, Steldt &
DeLaHunt
Claims
1. A terminal for electrically interconnecting sets of wires,
comprising:
a plurality of resilient conductive contact elements each having
spaced fingers defining at least two wire accepting slots
therebetween adapted for forceful entry of a wire segment under a
force sufficient to resiliently separate said fingers to form a
positive electrical connection with the wire;
a block of insulating material defining a plurality of terminal
sections each having opposite first and second surfaces, a
plurality of spaced bores in the block between said surfaces each
adapted to receive a said wire, and a plurality of sockets
extending from said first surface transverse of at least two
adjacent cavities, each of said sockets slidably receiving one of
said contact elements for movement from a first position with said
fingers spaced from the adjacent bores to afford positioning wires
therein, to an engaged position with the fingers across said
adjacent bores and said slots aligned therewith to engage wires
therein, each pair of adjacent bores in each terminal strip section
having one of the interconnecting contact elements; and
means for mounting said block to a structure with said second
surface spaced therefrom to afford engagement of the jaws of a
pliers like tool on said second surface and one of said contact
elements in the disengaged position to afford pressing the contact
element to the engaged position.
2. A terminal strip according to claim 1, further including
extraction means for affording movement of said contact elements
from the engaged to the disengaged position via the use of a
pointed tool such as a
3. A terminal strip according to claim 2, wherein said block has
notches along said first surface, with each notch being tapered in
depth toward and communicating with a different one of said
sockets, and each of said contact elements has an opening adapted
to receive the tip of said pointed tool and being positioned at the
bottom of said notch when said contact element is in the engaged
position, said notch affording insertion of a pointed tool along
said first surface and into said opening to provide
4. A terminal strip according to claim 2, wherein said block has
notches along said first surface, with each notch being tapered in
depth toward and communicating with a different one of said
sockets, and each of said contact elements has a tab projecting
normally from its end opposite the fingers, said tab being
positioned to project over one of said notches when said contact
element is in the engaged position, said notches and tabs affording
the insertion of a pointed tool therebetween to provide
5. A terminal strip according to claim 1, wherein at least one of
said contact elements includes a protrusion generally at a right
angle from its end opposite said fingers, said protrusion having a
generally centrally located tapped hole, and a screw threadably
engaged in said tapped hole
6. A terminal strip according to claim 1, wherein at least one of
said contact elements includes a rectangular tab at its end
opposite said fingers, said tab having sufficient length to project
above said first surface when the contact element is in the engaged
position and being the male tab of a quick connect terminal.
Description
BACKGROUND OF THE INVENTION
This invention relates to terminal strips for interconnecting
separate sets of wires.
Terminal strips are commonly used to electrically interconnect sets
of wires. A terminal strip typically includes an elongate block of
electrically insulating material adapted to be mounted to a
structure and having a plurality of screws in threaded sockets
spaced along the block, some of which may be electrically
connected. A set of wires is interconnected by connecting one end
of each wire to a common screw or to one of a series of
electrically connected screws. To make such a connection,
insulation must be stripped from the end of the wire. If the wire
is solid, the stripped end may then be bent in a U-shape and hooked
around a screw, whereas if the wire is stranded a special tip in
the form of an eyelet or fork should be engaged with the stripped
end and the tip then inserted under the head of the screw. The
screw is tightened with a screwdriver to complete the connection.
This connection process is tedious and requires an inordinant
amount of time particularly where a large number of connections
must be made and broken as during experimental work or the rewiring
of equipment.
While connectors are known which utilize contact elements having
spaced resilient fingers defining wire accepting slots to
interconnect two or more small gauge wires such as are disclosed in
U.S. Pat. Nos. 3,012,219, 3,388,370, 3,656,088 and 3,609,644, there
has heretofore been no known terminal strip which utilizes such
contact elements to interconnect separate sets of wires and which
is adapted to afford ease of connecting or disconnecting individual
wires in a set.
SUMMARY OF THE INVENTION
A terminal strip according to the present invention affords
efficient interconnection of sets of solid and/or stranded power
wires of up to No. 10 AWG by the simple process of positioning the
wire in a bore in the terminal strip and pressing a contact element
into engagement therewith with a conventional pliers. Additionally,
the connection to any one wire can be easily broken by prying the
contact element out of engagement with a screwdriver.
According to the present invention there is provided a terminal
strip for electrically interconnecting separate sets of wires. The
strip includes an elongate block of electrically insulating
material divided along its length into a plurality of terminal
strip sections. Each terminal strip section has opposite first and
second surfaces and a plurality of parallel spaced wire receiving
bores through the block between the surfaces. The block has a
plurality of sockets, each extending from the first surface
transverse of at least two adjacent bores. Each of the sockets
slidably receives one of a plurality of contact elements for
movement between a disengaged position with wire engaging fingers
of the contact element spaced from the bores to afford positioning
wires therein, and an engaged position with the fingers across the
adjacent bores to engage and interconnect wires therein. Each pair
of adjacent bores in each terminal strip section has one of the
interconnecting contact elements to afford interconnection between
wires in all the bores of one section.
The terminal strip includes means for mounting the block with the
second surface spaced from the mounting structure to afford
engagement of the jaws of a pliers on the second surface and one of
the contact elements so that the contact element may be pressed
toward the second surface to the engaged position. For each socket
the connector has a notch along the first surface which intersects
the socket and affords access for the tip of a bladed tool such as
a screwdriver with a contact element in the engaged position so
that the contact element may be pried to the disengaged position to
break the electrical interconnection between adjacent wires.
Also, a contact element may be included in the terminal strip which
includes a screw or the male tab of a quick connect terminal on the
end of the contact element which is exposed along the first surface
of the terminal strip when the element is engaged as may be
desirable under certain circumstances to afford a more conventional
connection to a wire.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be further described with reference to the
accompanying drawing wherein like numbers refer to like parts in
the several views, and wherein:
FIG. 1 is a perspective view of a terminal strip according to the
present invention interconnecting a set of wires in one terminal
strip section;
FIG. 2 is an enlarged section taken approximately along the lines
2--2 of FIG. 1 and illustrating a contact element of the terminal
strip being pressed into engagement with a wire via a pliers;
FIG. 3 is an enlarged section taken approximately along the lines
2--2 of FIG. 1 illustrating the contact element being disengaged
from the wire via a screwdriver;
FIG. 4 is an enlarged section taken approximately along the lines
4--4 of FIG. 1;
FIG. 5 is an enlarged section taken approximately along the lines
5--5 of FIG. 1;
FIG. 6 is an enlarged perspective view of a first embodiment of the
contact element used in the terminal strip of FIG. 1;
FIG. 7 is a perspective view of a second embodiment of a contact
element for use in the terminal strip of FIG. 1;
FIG. 8 is a perspective view of a third embodiment of a contact
element for use in the terminal strip of FIG. 1; and
FIG. 9 is a perspective view of a fourth embodiment of a contact
element for use in the terminal strip of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1 of the drawing there is illustrated a
terminal strip according to the present invention generally
designated by the numeral 10. The terminal strip 10 includes an
elongate block of electrically insulating material such as
polypropylene, divided along its length into a plurality of
terminal strip sections 12 (illustrated as three). Each terminal
strip section 12 has a plurality of sockets 13 shaped to slidably
receive conductive contact elements 14 adapted to interconnect
wires 16 inserted into parallel bores 18 therein.
The terminal strip sections 12 are rectangular, each having a first
surface 20 through which the contact elements 14 are mounted, an
opposite second surface 22, and opposed end surfaces 24. The
sections 12 are separated by projecting flanges 26 to restrict
arcing or accidental shorting between the exposed contact elements
14. Each section 12 has four wire receiving bores 18 in
communication between the end surfaces 24 which are equally spaced
and axially parallel, and are positioned midway between the first
and second surfaces 20 and 22.
Each terminal strip section 12 also has three of the sockets 13
spaced axially along the bores 18, with each socket 13 intersecting
two separate adjacent bores 18 at a right angle to the axis
thereof, and communicating between the first surface 20 and the two
bores 18 which it intersects. Each socket 13 slidably receives one
of the contact elements 14 for movement between a disengaged
position projecting above the first surface 20 (see the contact
elements 14 in the central terminal strip section 12 of FIG. 1 as
illustrated) with wire engaging fingers 30 on the contact element
14 spaced from the two intersected bores 18 to afford the insertion
of wires therein; and an inserted engaged position (see the contact
elements 14 in the left end terminal strip section 12 of FIG. 1)
with the end of the contact element 14 opposite the fingers 30
aligned with the first surface 20 and the fingers 30 transverse of
the adjacent bores 18 to pierce the insulation of and make an
electrical connection between wires therein. Each of the bores 18
is intersected by at least one of the sockets 13 and one of the
sockets 13 joins each pair of adjacent bores 18 in each terminal
strip section 12. Thus wires 16 in any two adjacent bores 18 can be
interconnected by one of the contact elements 14, and up to four
wires 16 may be interconnected in each terminal strip section 12 so
long as a bore 18 between wires 16 to be interconnected is not left
empty. Alternatively, interconnections between two separate sets of
two wires can be made in each terminal strip section 12 by leaving
the central contact element 14 in the disengaged position.
The elongate block has end mounting brackets 32 with feet 34 each
having a central notch 36 adapted for receiving a screw to attach
the terminal strip 10 to a mounting structure. The mounting
brackets 32 space the terminal sections 12 away from a structure on
which they are mounted and position the first and second surfaces
20 and 22 at about a 30.degree. angle thereto. This allows a
craftsman to conveniently use a pliers 38 to press one of the
contact elements 14 from the disengaged to the engaged position by
engaging one jaw of the pliers with the second surface 22 and the
opposite jaw with the upper edge of the contact element 14 exposed
along the first surface 20 (FIG. 2).
Each contact element 14 (FIG. 4) is a conductive resilient metal
plate-like member having the spaced fingers 30. The fingers 30
define two wire accepting slots 40 therebetween adapted for
forceful entry of a wire segment under a force sufficient to
resiliently separate the fingers 30, thereby forming a positive
electrical connection with the wire. The ends of the fingers 30 are
radiused to aid in spreading the fingers 30 and guiding a wire into
the slots 40, and the contact element has a relief slot 42 between
the inner two fingers 30 to afford proper flexure thereof. As
pressure is applied to force wires into the slots 40, the ends of
the fingers first penetrate any insulative covering on the wires,
and eventually partially deform the engaged wire segment. At the
same time, the resilient fingers 30 are forced apart and thus apply
a continual pressure against the conductor to maintain a positive
electrical connection.
As is best seen in FIG. 5, the block includes a pair of
transversely extending thin bars 43 in each socket 13 aligned with
the bores 18 intersected by the socket 13 and each having an upper
edge aligned with the wall of the adjacent bore 18 on the side
opposite the first surface 20. The bars 43 in each socket 13 are
positioned and are sufficiently thin to enter the wire accepting
slots 40 of a contact element 14 moved to the engaged position in
that socket 13 without deflecting its fingers 30. The upper edge of
each bar 43 provides means for supporting the segment of a wire in
the adjacent bore 18 which will be forced between the fingers 30 as
the contact element 14 is moved to the engaged position.
The terminal strip 10 also includes means for affording movement of
the contact elements 14 from the engaged to the disengaged position
via the use of a screwdriver 44 as is illustrated in FIG. 3. The
contact element 14 (illustrated most clearly in FIG. 6) has an
elongated opening 45 extending parallel to and adjacent its end
opposite the fingers 30. When the contact element 14 is in the
engaged position, the opening 45 is aligned with the bottom of a
notch 46 along the first surface 20 of the terminal strip section
12, which notch 46 is tapered in depth and intersects the socket
13. The tip of the screwdriver 44 may be inserted through the notch
46 and into the opening 45, and pivoted against the first surface
20 to pry the contact element 14 from the engaged to the disengaged
position.
Although this invention is subject to considerable variation
without departure from the spirit thereof it is believed that the
following specific example, adapted to interconnect wires of from
No. 18 AWG to No. 14 AWG, will facilitate understanding: Each
terminal strip section 12 is about 1 inch deep between the end
surfaces 24, 0.4 inch thick between the first and second surfaces
20 and 22, and 0.7 inch wide between the flanges 26. The five bores
18 are about 0.14 inch in diameter and spaced on 0.18 inch centers.
The end brackets 32 support the first and second surfaces 20 and 22
at an angle of about 30.degree. with a surface on which the
terminal strip is mounted, with the edge of the second surface 22
furthest from the mounting surface being spaced about 0.85 inch
therefrom. The contact element 14 is 0.036 inch thick and made of
tin plated spring tempered cartridge brass. The fingers 30 are
about 0.17 inch long, 0.06 inch wide, and the width of the wire
accepting slots 40 is about 0.025 inch.
FIG. 7 illustrates a second embodiment of a contact element adapted
for use in the terminal strip and generally designated by the
numeral 48. The contact element 48 has fingers 50, two wire
accepting slots 52 and a central relief slot 54 which are
essentially identical to the same portions of the contact element
14, the only significant difference being that instead of the
elongate opening 45, the contact element 48 has a tab 56 projecting
at right angles from its edge opposite the fingers 50. The contact
element 48 is positioned in its receiving socket 13 so that the tab
56 projects over the notch 46. When the contact element 48 is in
the engaged position, the tip of a screwdriver may be inserted in
the notch 46 between the first surface 20 and the tab 56 to pry the
contact element 48 to the disengaged position.
FIG. 8 illustrates a third embodiment of a contact element adapted
for use in the terminal strip and generally designated by the
numeral 60. The contact element 60 has fingers 61, two wire
accepting slots 62, a central relief slot 63 and an elongate
opening 64 adapted to receive the tip of a screwdriver which are
essentially identical to the corresponding portions of the contact
element 14. The contact element 60 has a protrusion 65 projecting
at right angles from its end opposite the fingers 61 and having a
generally central tapped hole adapted to receive a conventional
screw 66. The contact element 60 is positioned in its receiving
socket 13 so that tab 56 projects over the first surface 20 away
from the notch 46 with the screw 66 projecting at a right angle
away from the first surface 20. A wire may be interconnected with
wires engaged by the contact element 60 in the bores 18 by
attaching an end of the wire under the screw 66 in the conventional
manner.
FIG. 9 illustrates a fourth embodiment of a contact element adapted
for use in the terminal strip and generally designated by the
numeral 70. The contact element 70 has a tab 71 which is the male
tab portion of a quick connect terminal according to N.E.M.A.
Standard 7-15-1970. When the contact element 70 is in the engaged
position the tab 71 is positioned to project from the first surface
20 of the terminal strip to afford engagement with the female
connector of the quick connect terminal to interconnect a wire with
wires in the bores 18.
A first planar portion of the contact element 70 has fingers 72,
two wire accepting slots 73, a central relief slot 74 and an
elongate opening 75 transverse of its end opposite the fingers 72
adapted to receive the tip of a screwdriver which are essentially
identical to the corresponding portions of the contact element 14.
The contact element 70 also has a generally L-shaped extension from
the end of the planar portion opposite the fingers 72 including a
normally extending portion 76, and the tab 71 which extends
parallel to and in an opposite direction than the planar portion
from the end of the portion 76 opposite the planar portion. The
contact element is positioned in its receiving socket 13 so that
the portion projects over the first surface away from the notch 46.
Thus the portion 76 is positioned for engagement by the jaw of a
pliers to press the contact element 70 to the engaged position, and
the tab 71 projects from the first surface 20 to afford an
electrical connection therewith.
* * * * *