Overcurrent protection module

An overcurrent protection module includes a base unit and a removable fuse holder. The base unit is mountable on a panel or a DIN rail so that a containing space for the fuse holder stands perpendicular to a plane of the panel or the DIN rail, and in line with a conventional wiring orientation. The fuse holder includes at least three fuse slots arranged in a single plane, so that in a position inserted in the base unit, the fuse slots are perpendicular to the plane of the panel or DIN rail. Line terminals are singularly located on a first side wall of the base unit and load terminals are singularly located on a second side wall, opposite to the first side wall. The overcurrent protection module according to the invention is simpler to mount and requires less surface mounting space than a conventional fuse block. The overcurrent protection module also provides protection from shock hazard by shielding an operator from contact with live terminals or fuses.

FIELD OF THE INVENTION 
The present invention relates to fuses and to an overcurrent protection 
module including fuses. 
BACKGROUND AND SUMMARY OF THE INVENTION 
In control panels for electrical equipment, space is an important 
consideration for the positioning and spacing of the various devices and 
the routing of wires through the control panel. 
Conventional fuse holders for multiple fuse arrangements typically mount 
the fuses adjacent to one another and parallel to the back panel of the 
control panel, which takes up considerable space. In addition, the fuses 
and the connecting terminals are exposed, which can present a danger to an 
operator working in the panel. 
The present invention, generally, provides a fuse holder for three or more 
fuses that solves the problems of space and safety in the art. 
More particularly, the present invention provides an overcurrent protection 
module having a fuse holder for three or more fuses, for example, for a 
three-phase circuit, that takes up less room in a control panel than does 
a conventional fuse holder. The overcurrent protection module of the 
present invention is narrower than conventional fuse holders carrying the 
same number of fuses. 
The overcurrent protection module according to the present invention 
provides a unit that contains three or more fuses in an enclosed unit to 
protect an operator from contact with exposed electrical terminals or 
other live elements. The overcurrent protection module according to the 
present invention also provides a fuse holder in a base unit that is 
removable from the base unit to allow replacement of fuses in the fuse 
holder without exposing an operator to danger of electrical contact. 
According to another aspect of the present invention, the overcurrent 
protection module includes a base unit that mounts on a panel or a DIN 
rail so that a containing space in the base unit is positioned 
perpendicular to the plane of the panel or DIN rail, and in line with 
conventional wiring orientation. The overcurrent protection module also 
includes a fuse holder that inserts in the base unit. The fuse holder is 
formed to hold three or more fuses in a single plane that, in an inserted 
position of the fuse holder, is also perpendicular to the plane of the 
panel or DIN rail. 
According to a further aspect of the invention, the fuse holder includes 
individual slots for securing a fuse and means connecting each fuse in an 
electric circuit in the base unit. The electrical connection means 
includes plug-type connectors at the opposite end portions of the fuse 
slots. The plug-type connectors are positioned to connect with mating 
connectors in the base unit when the fuse holder is inserted in the base 
unit. According to the invention, the plug-type connectors are arranged 
parallel to the plane of the fuse slots. 
According to another aspect of the invention, load and line terminals are 
provided on opposite side walls of the base unit. All of the line 
terminals are located on a first side wall of the base unit and all of the 
load terminals are located on a second side wall, opposite to the first 
side wall. This arrangement simplifies electrically connecting the 
overcurrent protection module in the control panel and simplifies the 
routing of the connecting wires, which contributes both to safety and 
saving space on the control panel. 
According to yet another aspect of the invention, the electrical connection 
means to connect the fuses to the line and load terminals include 
electrical conductors connecting the plug-type connectors to the load and 
line terminals. The conductors for the load terminals are arranged in a 
single plane that is perpendicular to the plane of the plug-type 
connectors and parallel to the bottom portion of the base unit. Similarly, 
the conductors for the line terminals are also arranged in a single plane 
perpendicular to the plane of the plug-type connectors. The arrangement of 
the load and line conductors advantageously allows the at least three 
fuses to be arranged in a narrow space with the load and line terminals at 
opposite sides of the base unit. 
According to another aspect of the invention, the base unit electrical 
connection means comprises a first terminal block mounted in the base unit 
adjacent to the load terminals and a second terminal block mounted 
adjacent to the line terminals, both terminal blocks oriented parallel to 
the bottom of the base unit. Three individual connectors are supported by 
the first terminal block and positioned in a plane extending upwardly from 
the terminal block and perpendicular to the second side wall of the base 
unit. Each of the connectors is attached to an electrical conductor 
supported in the first terminal block. Each conductor is also connected to 
one of the load terminals. Three individual connectors are supported by 
the second terminal block and positioned in a row perpendicular to the 
first wall. Each of the connectors is attached to an electrical conductor 
disposed in the second terminal block, and each conductor is connected to 
one of the line terminals. 
According to a preferred embodiment of the invention, a portion of the 
second terminal block extends through the first side wall and supports the 
line terminals and a portion of the first terminal block extends through 
the second side wall and supports the load terminals. 
According to a preferred embodiment of the invention the base unit 
electrical connectors and the fuse holder electrical connection means 
include mating plug-type connectors for ease of connecting and 
disconnecting the fuse holder by movement of the fuse holder respectively 
into and out of the base unit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1 is a perspective view of a conventional fuse block 2 as is known in 
the art. The fuse block 2 is illustrated mounted to a DIN rail 20 by a DIN 
rail adapter 4. Typically, the DIN rail 20 is mounted on an inside wall in 
a control panel (not illustrated). The fuse block 2 includes three slots 5 
for mounting fuses. As may be seen, the fuse slots 5 are arranged side by 
side along the lengthwise or longitudinal direction 22 of the DIN rail 20. 
The longitudinal axes of the fuses are perpendicular to the longitudinal 
direction 22 of the DIN rail 20, and parallel to a widthwise or transverse 
direction 24 of the DIN rail. This arrangement, which is typical in the 
art, takes up much space along the DIN rail 20, and consequently, much 
space in the control panel in which the DIN rail is mounted. 
An overcurrent protection module 10 according to the present invention is 
illustrated in FIG. 2. The overcurrent protection module 10 is comprised 
of two main elements, a base, or housing, unit 30 and a removable fuse 
holder 50. The fuse holder 50 is illustrated in a removed position, and is 
also insertable in the base unit 30 to an inserted position. Each of the 
fuse holder 50 and base unit 30 include electrical connection means to 
establish an electrical circuit including the fuses through the 
overcurrent protection module 10, as further described below. 
The base unit 30 is a generally rectangular shaped housing having four side 
walls and a bottom 36 that define an interior receiving space 31 for the 
fuse holder 20. The base unit 30 in FIG. 2 is shown mounted to a DIN rail 
20. The base unit 30 is also panel mountable and the advantages of the 
invention described herein apply equally to such a configuration. 
The base unit 30 may be mounted to the DIN rail 20 in any convenient 
manner. For example, an adapter 70, illustrated in FIG. 3, may be fastened 
to the bottom 36 of the base unit 30 to mount the base unit to the DIN 
rail 20. 
The base unit 30 includes externally located terminals 32, 34 for 
connecting the base unit in an electrical circuit. According to the 
invention, the terminals 32, 34 are arranged so that the load terminals 
are singularly located on one side of the base unit 30 and the line 
terminals are singularly located on the opposite side of the base unit. In 
the embodiment illustrated in the figures, which is not meant to be 
restrictive, the terminals 32 on a first side wall 38 of the base unit 30 
are line terminals, and the terminals 34 on a second side wall 40 are all 
load terminals. The arrangement of the terminals 32, 34 on the base unit 
30 simplifies the wiring and routing of wires in a control panel to the 
overcurrent protection module 10 of the present invention. All of the line 
wires may be routed to a single side 32 of the module 30 and all of the 
load wires to an opposite side 34. This arrangement is particularly 
advantageous in modules having three or more fuses, for example, in 
modules for three-phase circuits. In situations where two or more modules 
30 are placed side-by-side, the wires to the terminals will not interfere 
with the tight positioning of the modules. 
The base unit 30 also includes a plurality of slotted openings 33 on the 
third and fourth side walls. The slotted openings 33 allow air to pass in 
and out of the space 31 containing the fuse holder 50 to provide cooling. 
The fuse holder 50 includes a handle 52 and main body portion 54. The main 
body portion 54 inserts in the base unit 30, and includes three fuse 
holding slots 56. A planar top 58 that closes off the containing space in 
the base unit 30 when the fuse holder 50 is in the inserted position. 
Indicator lamps 60 are mounted on the top 58 of the fuse holder 50. The 
indicator lamps 60 are each integrated with a fuse holding slot 56 and are 
connected in a circuit to light when the fuse needs to be replaced, that 
is, when the fuse has blown. 
The fuse holding slots 56 are positioned in a single plane that is 
perpendicular to the plane of the top 58. When the fuse holder 50 is in 
the inserted position, the fuse slots are perpendicular to the bottom 36 
and perpendicular to the first 38 and second 40 side walls of the base 
unit 30. In contrast to the conventional fuse block 2 of FIG. 1, the fuses 
in the overcurrent protection module 10 according to the present invention 
are oriented in a plane perpendicular to the plane of the mounting 
surface. As shown in FIG. 2, the fuses in module 10 are oriented 
perpendicular to the plane of the DIN rail 20 (defined by the longitudinal 
22 and transverse 24 directions), and parallel to the transverse direction 
24 of the DIN rail. 
FIG. 4 is a side sectional view of the overcurrent protection module 10 
showing the fuse holder 50 in an inserted position in the base unit 30. 
The view of FIG. 4 is along a plane through the center fuse holding slot. 
The indicator lamps 60 include means 68 for lighting the lamp 60 when a 
fuse has blown to indicate that the fuse must be replaced. 
In the inserted position, the fuse holder 50 electrically connects to the 
base unit 30 to form electrical circuits for each of the fuses in the fuse 
holder. A single fuse 57 and fuse slot 56 are illustrated in the section 
shown in FIG. 4, however, it is understood that the fuse holder 50 is 
formed to hold three or more fuses and the description of the one 
illustrated fuse slot applies other fuse slots in the fuse holder. A first 
contact 62 at a first end of the fuse holding slot 56 contacts one end of 
the fuse 57 and includes a first electrical connector 63 that mates with 
an electrical connector 42 of the base unit 30. In the embodiment 
illustrated, the electrical connectors 63, 42 are plug-type connectors 
that facilitate making a reliable electrical connection when the fuse 
holder 50 is inserted in the base unit 30. The base unit connector 42 is 
formed as a blade and the fuse holder connector 63 is formed as a slot to 
accept the blade. Of course, other suitable connectors may be used. A 
second contact 64 at the second end of the fuse slot 56 makes contact with 
the opposite end of the fuse 57 and includes a second electrical connector 
65 that mates with an electrical connector 44 of the base unit 30. The 
electrical connectors 65 and 44 are also plug-type connectors. The fuse 
holder connector 65 is formed as a blade and the base unit connector 44 is 
formed as a slot for accepting the blade 65 in the embodiment illustrated. 
The electrical connectors 63 at the first end of the fuse slot are arranged 
in a single first plane adjacent to the first end, as illustrated. The 
electrical connectors 65 for the second end are arranged in a single 
second plane that extends from the second end of the fuse slot 56. The 
first and second planes are parallel to the plane in which the fuse slots 
56 are positioned, as may be understood by reference to FIG. 2. The base 
unit connectors 42, 44 are also positioned in planes to mate with the fuse 
holder connectors when the fuse holder 50 is inserted into the base unit 
30. 
The base unit electrical connectors 42, 44 are respectively supported by a 
first terminal block 46 and a second terminal block 48 mounted in the base 
unit. FIGS. 5 and 6 illustrate a first terminal block 46 and FIGS. 7 and 8 
illustrate a second terminal block 48. The terminal blocks 46, 48 are 
substantially planar supporting elements and include the electrical 
connectors for connecting the base unit 30 to the fuse holder 50. 
According to a preferred embodiment, the terminals 32, 34 are supported on 
a portion of the terminal blocks 46, 48 that extends through openings in 
the first and second walls 38, 40 of the base unit 30 for access from 
externally of the base unit. The terminal blocks 46, 48 also include 
electrical conductors leading from and connecting the connectors 42, 44 to 
the terminals 32, 34, respectively. 
As shown in FIGS. 5 and 6, which is a top view of the first terminal block 
46, three connectors 42a, 42b and 42c are supported by the terminal block 
46 and extend upward (relative to the view of FIG. 6) from the terminal 
block in a single plane. The load terminals 34 consist of three individual 
terminal pads 34a, 34b and 34c which are supported by the terminal block 
46, and are arranged along a line perpendicular to the line of the 
connectors 42a, 42b, 42c. Each of the connectors 42a, 42b, 42c is 
connected to one of the load terminal pads 34a, 34b and 34c by a conductor 
43a, 43b, 43c. The conductors 43a, 43b, 43c are supported in the terminal 
block 46 and are electrically isolated from each other. The routing of the 
conductors 43a, 43b, 43c permits the relative orientation of the terminals 
34 and the connectors 42. As may be seen in FIG. 4, the first terminal 
block 46 is positioned in an upper portion of the base unit so that the 
connectors 42 mate with the first fuse holder connectors 63. The first 
terminal block 46 is shaped to allow space in the base unit 30 for the 
fuse holder 50 in the inserted position. 
FIGS. 7 and 8 illustrate, respectively, a top view and the side view of a 
second terminal block 48. The three connectors 44a, 44b and 44c are 
supported by the terminal block 48 in a single plane. The line terminals 
32 include three individual terminal pads 32a, 32b, 32c supported by the 
terminal block 48 in a line perpendicular to the line in which the 
connectors 44a, 44b, 44c are positioned. Each of the connectors 44a, 44b, 
44c is connected by a conductor 45a, 45b, 45c to one of the terminal pads 
32a, 32b, 32c. The conductors 45a, 45b, 45c comprise flat electrically 
conductive material supported in the terminal block 48 and electrically 
isolated from one another. 
The foregoing has described the preferred principles, embodiments and modes 
of operation of the present invention; however, the invention should not 
be construed as limited to the particular embodiments discussed. Instead, 
the above-described embodiments should be regarded as illustrative rather 
than restrictive, and it should be appreciated that variations, changes 
and equivalents may be made by others without departing from the scope of 
the present invention as defined by the following claims.