Abstract:
A circuit protection assembly employs a post arrangement that is easier to manufacture and has a built-in insulating fuse configuration. The circuit protection assembly is disposed between a source of power and a circuit to be protected. The circuit protection assembly includes comprises a mounting block having a bore extending therethrough and a recess cavity on a first surface of the mounting block. A post having a first end is disposed within the recess cavity and a body portion extends through the bore. A fuse having a centrally disposed aperture is configured to receive the body portion of the post. The post has a second end configured to receive a terminal for connection to a circuit to be protected.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the invention relate to the field of circuit protection devices. More particularly, the present invention relates to a fuse assembly employing a post arrangement that is easier to manufacture and provides a built-in insulating configuration with the fuse. 
     2. Discussion of Related Art 
     Fuses are used as circuit protection devices and form an electrical connection between a power source and a component in a circuit to be protected. In particular, a fuse may be configured to protect against damage caused by an overcurrent condition. A fuse is constructed to physically open or interrupt a circuit path and isolate electrical components from damage upon the occurrence of specified overvoltage and/or overcurrent conditions in the circuit. 
     Electrical systems in vehicles typically include a number of these types of circuit protection devices to protect electrical circuitry, equipment, and components from damage caused by these conditions. For example, power sources (e.g. batteries) in vehicles utilize a fuse fitted over a terminal post to which a ring terminal of an electrical cable is connected. A nut is usually threaded onto the post to keep the ring terminal and fuse in position. When an excess current condition exists, the fuse on the terminal post protects the components connected to the power source from this excess current. Unintended shorting occurs when the ring terminal comes into direct electrical contact with the post rather than through the fuse. To overcome this problem, an insulating nut fitted over the post has been used to isolate the fuse and the ring terminal to prevent current from bypassing the fuse and damaging the protected circuit. 
     In certain applications, a single source of power may be shared with a plurality of these fuse arrangements to distribute power to multiple circuits. For example,  FIG. 1  is a side cross-sectional view of a fuse assembly  10  illustrating a housing or block  20  from which a post  25  extends and on which fuse  30  is mounted. A ring terminal  40  is fitted over post  25 . Ring terminal  40  is connected to a power cable  41  to supply power to an electrical circuit to be protected. Ring terminal is configured to make electrical contact with an upper terminal of fuse  30 , but is insulated from post  25 . In this configuration, power is supplied to a bus bar  45  disposed in block  20  which is connected to a lower terminal of fuse  30 . In this manner, fuse  30  connects the bus bar  45  with ring terminal  40  via fuse element  35 . When an overcurrent condition occurs, the fuse element  35  opens or otherwise prevents the flow of current from the bus bar  45  to ring terminal  40  thereby protecting the electrical circuit. Post  25  is molded within block  20  which is typically made from plastic. Unfortunately, by molding one end of post  25  into block  20 , additional manufacturing steps and associated costs are incurred. Accordingly, there is a need to provide a fuse assembly that includes a post or terminal portion that is easier to manufacture and provides an insulating configuration to prevent unnecessary short circuits. 
     SUMMARY OF THE INVENTION 
     Exemplary embodiments of the present invention are directed to a protection device disposed between a source of power and a circuit to be protected. In an exemplary embodiment, a circuit protection assembly comprises a mounting block having a bore extending therethrough and a recess cavity on a first surface of the mounting block. A post having a first end is disposed within the recess cavity and a body portion extends through the bore. A fuse having a centrally disposed aperture is configured to receive the body portion of the post. The post has a second end configured to receive a terminal for connection to a circuit to be protected. 
     In another exemplary embodiment, a circuit protection assembly comprises a mounting block having an upper surface and a lower surface. A plurality of posts is included where each of the posts extends from the upper surface of the block. A plurality of fuses each defined by a first and second terminals and a fuse element connecting the first and second terminals where each of the first terminals of the fuses having a centrally disposed aperture configured to receive a respective one of the plurality of posts. A bus bar extends along a length of the bottom surface of the mounting block where the bus bar defines the second terminal of each of the fuses. A power connection assembly is located at a first end of the mounting block and is configured to supply power to the bus bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a prior art fuse assembly employing a post integrally molded with an block. 
         FIG. 2A  illustrates an exploded perspective view of an exemplary fuse assembly in accordance with an embodiment of the present disclosure. 
         FIG. 2B  illustrates a perspective bottom view of the fuse assembly of  FIG. 2A  in accordance with an embodiment of the present disclosure. 
         FIG. 2C  is a cross-sectional side view of a portion of a fuse assembly shown in  FIGS. 2A and 2B . 
         FIG. 3A  illustrates an exploded perspective view of a fuse utilized in an assembly in accordance with an embodiment of the present disclosure. 
         FIG. 3B  is a top plan view of a fuse utilized in an assembly in accordance with an embodiment of the present disclosure. 
         FIGS. 4A-4D  are various perspective views of an assembly in accordance with an alternative embodiment of the present disclosure. 
         FIG. 5  is a perspective view of an exemplary embodiment in accordance with alternative embodiments of the present disclosure. 
         FIGS. 6A-6B  are perspective views of an exemplary embodiment in accordance with alternative embodiments of the present disclosure. 
         FIG. 7  is an exploded perspective view of an exemplary embodiment in accordance with the present disclosure. 
         FIG. 8A  is a perspective view of an exemplary embodiment in accordance with the present disclosure. 
         FIG. 8B  is a side view of the exemplary embodiment shown in  FIG. 8A  in accordance with the present disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention, however, may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements throughout. 
       FIG. 2A  is a perspective view of a fuse assembly  100  including a housing or block  120  on which one or more fuses  130  are mounted. In this illustration, one fuse  130  is shown with two posts  125  and  155  where post  155  supplies power to a bus plate  131  and post  125  receives fuse  130 . In particular, first post  125  is disposed through a receiving bore in block  120  and a corresponding bore in bus plate  131 . Fuse  130  may be a ceramic “block” fuse having a generally central aperture (as shown in  FIG. 3B ) that receives post  125 . An insulator  126  isolates post  125  from fuse  130 . Ring terminal  140 , connected to cable  141 , is mounted over post  125  and nut  145  threadedly engages the post to retain both the fuse and the ring terminal in position. A second post  155  extends through block  120  and is in electrical contact with bus bar  131  to provide power thereto. Post  155  is also threaded and receives ring terminal  150  and nut  155 . Cable  151  is connected to post  155  via ring terminal  150  to distribute power to the fuse assembly via bus bar  131 . In this manner, a circuit is formed from ring terminal  150 , to bus plate  131 , through fuse  130 , to ring terminal  140  to a component and/or circuit to be protected. Thus, power is supplied to the assembly at one location (e.g. ring terminal  150  and bus plate  131 ) and distributed to circuits through respective fuse assemblies (e.g. fuse  130 ). 
       FIG. 2B  is a bottom view of assembly  100  illustrating the retaining configuration of posts  125  and  155  within block  120 . In particular, the bottom side of block  120  includes recesses sized slightly larger than the heads of each post  125 ,  155  within which these heads are disposed such that the respective posts are secured in position through block  120 . Posts  125  and  155  may be force fit into respective recesses of block  120  where the recesses have the same shape as respective heads of each post  125 ,  155  with body portions of each of the posts extending through block  120 . In this manner, the posts do not need to be integrally molded with block  120 , thereby reducing manufacturing and labor costs. 
       FIG. 2C  is a cross-sectional side view of a portion of a fuse assembly shown in  FIGS. 2A and 2B . As can be seen, the head  125   a  of post  125  is recessed within block  120 , but not molded therein. Insulator  126 , which is a separate component and not molded as part of block  120 , extends from the head  125   a  along post  125  into a lower end of fuse  130  to insulate the post  125  from bus bar  131 . By not molding post  125  and insulator  126  within block  120 , manufacturing costs are conserved. The fusible element  136  is connected to a lower fuse terminal  135 ′ which is in electrical contact with bus bar  131 . In normal operating conditions, an electrical connection is formed between bus bar  131 , lower fuse terminal  135 ′, fusible element  136 , upper fuse terminal  135  and ring terminal  140 . When an overcurrent event occurs, fusible element  136  is blown or otherwise breaks this electrical connection. 
       FIG. 3A  is a perspective view of a block fuse  130  and  FIG. 3B  is a top plan view thereof. Fuse  130  is defined by a housing  130 ′ which may be made from, for example, a ceramic material, and has a centrally disposed aperture  127  through which post  125  is received. Fuse  130  includes a fuse element  136  which is in electrical contact with ring terminal  140  via terminal  135  to provide an electrical path to a circuit to be protected for power supplied to bus bar  131 . Fuse element  136  may also include a retaining flange  137  which extends toward housing  130 ′ to assist in the retention thereof. Fuse  130  also includes a cover  180  which protects fusible element  136  from ambient particles as well as acting to contain arcing when the fuse is blown due to an overcurrent condition. The cover is at least partially disposed in grooves  185  of fuse body  130 ′ which helps to retain the cover in position. 
       FIGS. 4A-4D  are various perspective views of an assembly  200  in accordance with an alternative embodiment of the present disclosure. Instead of separate fuses  130  shown in  FIGS. 2-3 , this embodiment incorporates fuses  230   1  . . .  230   N  and block  220  into a unitary assembly. In particular,  FIG. 4A  illustrates a block  220  including a bus bar  231  disposed on the bottom of the block that extends the length of the block (see  FIG. 4D ). A first portion  229  of the assembly  200  defines a connection to a power supply when a power supply cable is connected to post  225   1 . The bus bar  231  is connected to post  225   1  via an electrical connection (not shown) around the outside of block  220 . The remaining portions of block  220  define fuses  230   1  . . .  230   N  each having separate fuse elements  236   1  . . .  236   N  connecting bus bar  231  which acts as a first terminal for each fuse to a second terminal  235   1  . . .  235   N . As shown, fuse element  236   1  is used to electrically connect bus bar  231  to a terminal  235   1  to define fuse  230   1 . Each of the fuses  230   1  . . .  230   N  may also include covers  237   N  which cover respective fusible elements  236   1  . . .  236   N . 
       FIG. 4B  is used to illustrate just the posts  225   1  . . .  225   N  and block  220  without the fusible elements or busbar to show how the posts are positioned within recesses of block  220  for connection to a ring terminal. In particular, block  220  is shown with empty recesses  228   1  . . .  228   N  where the fuse elements  231   1  . . .  236   N  would be disposed. The head of each post  225   1  . . .  225   N  is positioned in block  220 . This allows each post to only extend from block  220  through a respective terminal  235   1  . . .  235   N  of each fuse. This eliminates the need to insulate each of the posts  225   1  . . .  225   N  since each post only protrudes through a corresponding one of the terminals  235   1  . . .  235   N  and does not contact bus bar  231 . In addition, since no insulator is used, the compression forces that exist once a fuse is mounted on a post  225   1  . . .  225   N  are limited to the contact point between the post and the respective fuse terminal. In this manner, each post  225   N  is in direct contact with a respective terminal  235   N  of a corresponding fuse  230   N . This eliminates the need for an insulator to be used which can withstand the compression force of a bolt down joint since all the compression force is directly between the fuse terminal and a respective post. In previous designs, specialty plastics were needed to form the insulators as well as block  220 . These costly specialty plastics were selected to withstand heat during use as well as the compression forces generated when a fuse is bolted to a post. In contrast, since the posts of the present disclosure  225   1  . . .  225   N  do not extend through the block  220 , this obviates the need for a costly high temperature plastic or ceramic to be used that can withstand these compression forces. 
       FIG. 4C  is a cut-away cross section of the assembly showing a particular fuse  230   N  having a first terminal defined by a corresponding portion of bus bar  231 , second terminal  235   N  connected by a fuse element  236   N  and a post  225   N  that extends upward through an aperture in second terminal  235   N  for connection to a ring terminal. Each fuse also includes a cover  280   N  as described in  FIG. 3B  which protects the respective fusible element  236   N . 
       FIGS. 5-7  are various views of assemblies in accordance with alternative embodiments of the present disclosure including different configurations of the terminals, block, posts and fusible elements.  FIG. 5  illustrates assembly  500  comprising a block  520  with a pair wise or side-by-side post  525   1  . . .  525   N  configuration adapted to receive block fuses (e.g.  130  shown in  FIG. 3A ). Block  520  may be a unitary piece of, for example, plastic, including a bus bar  531  disposed on the bottom of the block  520  that extends the length and width of the block. A first portion  529  of the bus bar  531  of the assembly  500  defines a connection to a power supply when a power supply cable is connected thereto. 
     Fuses  530   1  . . .  530   N  each have separate fuse elements  536   1  . . .  536   N  connecting bus bar  531  which acts as a first terminal for each fuse to a corresponding second terminal  535   1  . . .  535   N  of the fuse. For example, fuse element  536   1  is used to connect bus bar  531  to terminal  535   1  to define fuse  530   1 . Each of the fusible elements is disposed a distance away from wall  520 A of block  520  since the temperature of each of the fusible elements increases during use and should not come in contact with the plastic material of block  520 . 
     Each of a plurality of posts  525   1  . . .  525   N  is positioned in block  520  via grooved recesses  527 . This allows each post to only extend from block  520  through a respective second terminal  535   1  . . .  535   N  and does not contact bus bar  531 . As stated above with respect to the previous embodiments, since the posts do not extend all the way through the block  520 , this obviates the need for a costly high temperature plastic or ceramic to be used for the block capable of withstanding compression forces when terminals are connected to the posts. Spacers or guards  534   N  may be disposed between each of terminals  535   N  to separate each of the terminals  535   1  . . .  535   N  and post combinations. 
       FIGS. 6A-6B  illustrate another embodiment of an assembly  600  in accordance with the present disclosure.  FIG. 6A  is a top perspective view of assembly  600  and  FIG. 6B  is a perspective exploded view of the same assembly  600 . Assembly  600  includes a block  620  defined by a first sub-block  620 A and a second sub-block  620 B. In this embodiment, the bus bar (e.g.  531  shown in  FIG. 5 ) is defined by a first portion  631 A positioned on the bottom of first sub-block  620 A and a second sub-portion  631 B positioned on the bottom of second sub-block  620 B. The bus bar portions  620 A,  620 B define a first terminal of each of the fuses  630   1  . . .  630   N  and the second terminal is defined by respective portions  635   1  . . .  635   N . Each of the posts  625   1  . . .  625   N  is adapted to receive exemplary ring terminals shown, for example, in  FIGS. 1 and 2 . 
     A connection portion  629  receives a power supply cable for the assembly  600 . The connection portion  629  is defined by a first connection portion  629 A adapted to receive, for example, a ring terminal of the power supply cable and a second connection portion  629 B via aperture  629 B′. An additional fusible element  636   N+1  (shown more clearly in  FIG. 6B ) may be disposed between first and second connection portions  629 A and  629 B and disposed within housing  628 . 
       FIG. 6B  illustrates an exploded view of assembly  600  in which the fuse portions  630   1  . . .  630   N  are shown as a unitary section defined by respective bus bar portions  631 A and  631 B, fusible elements  636   1  . . .  636   N  and terminals  635   1  . . .  635   N . These unitary pieces are disposed around respective block portions  620 A and  620 B with posts  625   1  . . .  625   N  protruding through aperture in each of the upper terminals  635   1  . . .  635   N . A first cover  680 A and a second cover  680 B are used to cover respective fusible elements  636   1  . . .  636   N . A first side of each of sub-blocks  620 A and  620 B has recesses  621  and protrusions  622  that are aligned to fit the two sub-blocks together to form block  620 . 
       FIG. 7  is an exploded perspective view of an alternative assembly  700  in accordance with the present disclosure. In this embodiment, block  720  is a unitary piece and is configured to receive a unitary fuse assembly shown generally as  730 A. The unitary assembly  730 A is defined by bus bar  731  and fuses  730   1  . . .  730   N . The bus bar  731  forms the first terminal of each of the fuses and second terminals  735   1  . . .  735   N  are electrically connected to the first terminal via fusible elements  736   1  . . .  736   N  disposed therebetween, respectively. 
     Block  720  includes a first and second recesses  721 A,  721 B which are configured to receive first and second post blocks  722 A,  722 B of first and second post assembly  790 A and  790 B ( 790 A is shown positioned within unitary assembly  730 A and  790 B is shown outside of unitary assembly  730 A for ease of illustration). In this manner, a block  720  slides into the unitary assembly and receives the post assemblies  790 A and  790 B or unitary assembly  730 A slides over block  720  with post assemblies  790 A and  790 B at least partially disposed within recesses  721 A and  721 B. 
       FIG. 8A  is an exploded perspective view of an alternative embodiment of an assembly  800  in accordance with the present disclosure. In this embodiment, block  820  may be a unitary or multiple piece block with a first portion  820 A configured with posts  825   1 ,  825   2  for connection to one or more connection cables and a second portion  820 B receiving female fuse portions  835   N−2  . . .  835   N  as described below. A unitary assembly, shown generally as  830 A, is defined by bus bar  831  and fuses  830   1  . . .  830   N . The bus bar  831  forms the first terminal of each of the fuses and second terminals are illustrated as  835   1  . . .  835   N  with fusible elements  836   1  . . .  836   N  disposed therebetween, respectively. Terminals  835   N−2  . . .  835   N  may be configured as male terminals for insertion into recesses  832   1  . . .  832   N . A plurality of locking portions  823   1  . . .  823   N  are disposed on the top of block portion  820 B to retain connection to each of the female fuse portions  835   N−2  . . .  835   N . This may be seen more clearly with reference to  FIG. 8B  which illustrates a side view of assembly  800 . The recesses  832   1  . . .  832   N  extend through block portion  820 B to the other side thereof to receive a connection to the female fuse portions  835   N−2  . . .  835   N  which are retained in place via locking portions  823   1  . . .  823   N . 
     While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claim(s). Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.