The field of the invention relates generally to an inline fuse holder assembly.
Fuses are widely used as overcurrent protection devices to prevent costly damage to electrical circuits. Fuse terminals typically form an electrical connection between an electrical power source and an electrical component or a combination of components arranged in an electrical circuit. One or more fusible links or elements, or a fuse element assembly, is connected between the fuse terminals, so that when electrical current through the fuse exceeds a predetermined limit, the fusible elements melt and open one or more circuits through the fuse to prevent electrical component damage.
A variety of different types of fuse holders are known to provide electrical interfaces for overcurrent protection fuses. One type of fuse holder is an inline fuse holder that electrically connects a ferrule fuse within an electrical system. Among several applications, the inline fuse holder may be used in solar photovoltaic systems. The inline fuse holder assembly typically comprises a holder body having two pieces that releasably attach to one another using a compression nut and define an interior space for receiving the fuse. In some circumstance, it may be rather tedious and time consuming for a technician in the field to have to tighten the compression nut using a tool in order to connect the two pieces of the fuse holder assembly.
In addition, at least two contacts of the inline fuse electrically connect to the terminals of the fuse when the fuse is received in the fuse holder body. The contacts include wire connectors that extend outside the holder body. The wire connectors are connectable to (e.g., crimped onto) wires that are electrically connected to the electrical system. These connections between the wire connectors and the wires are exposed to the environment. Thus, a pair of insulating boots must be slid over the inline fuse holder (as generally known in the art) to cover and insulate the fuse holder body and these connections.
Non-limiting and non-exhaustive embodiments are described with reference to the following Figures, wherein like reference numerals refer to like parts throughout the various drawings unless otherwise specified.
Referring now to drawings, one example of an inline fuse holder assembly is generally indicated at reference numeral 10. As seen in
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The wire connectors 22, 24 may be crimped over the ferrule terminals 20, using a suitable crimping tool (e.g., Sta-Kon® Comfort Crimp® Compression Tool by Thomas & Betts), to make a non-releasable connection. The wire connectors 22, 24 may be attached to the ferrule terminals 20 in other ways. In another embodiment, the ferrule terminals 20 and the wire connectors 22, 24 may be integrally formed as single, one-piece components. In one non-limiting example, the wire connectors 22, 24 are configured for crimping, using a suitable crimping tool (e.g., Sta-Kon® Comfort Crimp® Compression Tool by Thomas & Betts), to connect the wires 26, 27 inside the wire connectors. The wire connectors 22, 24 may be formed from tin plated copper or other electrically conductive material. It is understood that wire connectors 22, 24 may be of other types and have other configurations without departing from the scope of the present invention. In one example, the fuse 18 may be a photovoltaic (PV) fuse for use in solar panel applications. One suitable, non-limiting example are PV fuses sold by Cooper Bussmann, St. Louis, Mo., USA and more specifically their fuses having PV series product numbers, such as product number PV-15A10F and similar fuses.
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Upon mating of the first and second connectors 32, 42, the annular barbs 52 resiliently deflect and then rebound (i.e., “snap”) into the corresponding annular grooves 54 to form a non-releasable connection. In other words, the connection between the first and second connectors 32, 42 is non-releasable in and of itself, and it is not necessary to apply other components (e.g., a lock) or materials (e.g., adhesive) to make the connection non-releasable, although such components (e.g., a lock) or materials (e.g., adhesive) may be used as an additional safeguard. The first and second connectors 32, 42 may be configured in other ways such that a non-releasable connection is formed upon connection of the first and second connectors.
In one embodiment, the connection between the first and second connectors 32, 42 is also substantially waterproof to inhibit water and other contaminants from entering into the fuse holder assembly 10. For example, in the illustrated embodiment the annular barbs 52 do not completely rebound to their at-rest positions when they snap into the corresponding annular grooves 54. As such, the annular barbs 52, when received in the corresponding annular grooves 54, apply a constant compressive force against walls of the second connector 42. The compressive force between the annular barbs 52 and the walls of the second connector 42 are of a sufficient magnitude to inhibit water and other contaminants from entering therebetween. As can be understood, the engagement between the snap-fit components 52, 54 is substantially waterproof upon mating of the first and second connectors 32, 42. Thus, the snap-fit components 52, 54 themselves form a substantially waterproof seal upon mating of the first and second connectors 32, 42. In other words, the connection between the first and second connectors 32, 42 is substantially waterproof in and of itself, and it is not necessary to apply other components (e.g., a waterproof seal) or materials (e.g., waterproof adhesive) to make the connection substantially waterproof, although such components (e.g., a waterproof seal) or materials (e.g., waterproof adhesive) may be used as an additional safeguard. The first and second connectors 32, 42 may be configured in other ways such that a substantially waterproof connection is formed upon connection of the first and second connectors.
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In one embodiment, each of the first and second fuse holder components 12, 14 may be formed as a single, one-piece component, such as by molding. The first and second fuse holder components 12, 14 may be formed from a suitable substantially waterproof, electrically insulating material, such as a suitable plastic material, and may be molded or constructed in other ways. In one non-limiting example, the first and second fuse holder components 12, 14 may be a suitable thermoplastic rubber (also called “thermoplastic elastomer”), such as a suitable thermoplastic rubber having a hardness of about 50 Shore A to about 75 Shore A. For example, a suitable thermoplastic rubber is sold by Exxon Mobil Corporation, New Jersey, USA, and sold under the mark Santoprene®. In one non-limiting example, the first and second fuse holder components 12, 14 may be made from Santoprene® 101-64 having a hardness of about 69 Shore A.
In such an example, such as an example where the first and second fuse holder components 12, 14 are generally non-rigid (e.g., formed from a thermoplastic rubber), at least one of the first and second components 12, 14 may include a plurality of internal, longitudinal ribs 60 (
In a non-limiting example of assembly, the wire connectors 22, 24 are crimped onto the respective ferrule terminals 20 of the fuse 18 to form the fuse assembly 16. Optionally, the waterproof, dielectric outer layer 28 (e.g., heat shrink) is applied to the fuse assembly 16 to substantially encase the fuse assembly 16. The fuse assembly 16, which may include the outer layer 28, may be sold as a pre-assembled component and delivered to the field in this pre-assembled configuration for use with the fuse holder assembly 10. Alternatively, the fuse assembly 16 may be sold as separate parts (e.g., separate fuses 18, wire connectors 22, 24, and outer layers 28) and assembled by the user, such as a technician, in the field.
With the fuse assembly 16 assembled (e.g., pre-assembled), the wire receiving portions 34, 44 of the respective first and second fuse holder components 12, 14 are cut transversely at the selected stepped external diameters corresponding to the selected gauges of the first and second wires 26, 27. The first and second wires 26, 27 are then inserted through the newly formed openings and into the respective first and second wire receiving portions 34, 44. The first and second wires 26, 27 are pulled through the open longitudinal ends 30a, 40a of the respective first and second fuse holder components 12, 14, and then the first and second wire connectors 22, 24 are crimped onto the respective first and second wires 26, 27.
In one example, the first wire 26 is attached to the first wire connector 22 before connecting the second wire 27 to the second wire connector 24. After connecting the first wire 26 to the first wire connector 22, the fuse assembly 16 is inserted into the first fuse holder component 12. Because, in one example, the first fuse holder component 12 has the relatively long fuse assembly-receiving cavity 38 and the plurality of internal longitudinal ribs 60, the fuse 18 is held securely and safely in the first fuse holder component 12 as second wire 27 is being connected to the second wire connector 24.
With the first and second wires 26, 27 connected to the fuse assembly 16, the first and second connectors 32, 42 are mated together, such as by engaging the snap-fit components 52, 54, to form a non-releasable, substantially waterproof connection. In one example, where the first and second wires 26, 27 are already connected to the electrical system, the installation is complete after connecting the first and second fuse holder components 12, 14 together. In another example, where the first and second wires 26, 27 are lead wires, the inline fuse holder assembly 10, with the fuse assembly 16 enclosed therein, is then electrically connected to an electrical system by connecting the first and second wires 26, 27 to the electrical system. It is contemplated that the first and second fuse holder components 12, 14 may be sold together and delivered to the field for assembly with the fuse assembly 12. It is also contemplated that the completed assembly (i.e., the fuse holder assembly 10, the fuse assembly 16 enclosed therein, and the first and second wires 26, 27 connected to the fuse assembly) may be pre-assembled as a single component and delivered to field for installation by connecting the first and second wires 26, 27 to the system.
In a non-limiting example of replacing the fuse assembly 16, for whatever reason, the entire completed assembly (i.e., the fuse holder assembly 10, the fuse assembly 16 enclosed therein, and the first and second wires 26, 27 connected to the fuse assembly) must be replaced because the fuse holder components 12, 14 are non-releasably connected.
An inline fuse holder is disclosed. The inline fuse holder assembly is for enclosing a fuse assembly including a fuse, and first and second wire connectors at respective first and second longitudinal ends of the fuse assembly. The inline fuse holder assembly includes a first fuse holder component having an open first longitudinal end and a second longitudinal end. The first component includes a first connector adjacent the first longitudinal end of the first fuse holder component, a first wire receiving portion adjacent the second longitudinal end of the first fuse holder component, and a first body portion intermediate the first connector and the first wire receiving portion. The first fuse holder component defines a first fuse assembly-receiving cavity, extending from the first longitudinal end toward the second longitudinal end and terminating before the first wire sealing portion, for receiving the first longitudinal end of the fuse assembly through the first longitudinal end of the first fuse holder component. The first wire receiving portion is configured for receiving a first wire connectable to the first wire connector when the fuse assembly is received in the fuse assembly-receiving cavity. A second fuse holder component has an open first longitudinal end and a second longitudinal end, the second component includes a second connector adjacent the first longitudinal end of the second fuse holder component, a second wire receiving portion adjacent the second longitudinal end of the second fuse holder component, and a second body portion intermediate the second connector and the second wire receiving portion. The second fuse holder component defines a second fuse assembly-receiving cavity, extending from the first longitudinal end toward the second longitudinal end and terminating before the second wire sealing portion, for receiving the second longitudinal end of the fuse assembly through the first longitudinal end of the second fuse holder component. The second wire receiving portion is configured for receiving a second wire connectable to the second wire connector when the fuse assembly is received in the fuse assembly-receiving cavity. The first and second connectors include mateable, non-releasable connection components configured to connect the first and second fuse body portions to one another and form a substantially waterproof, non-releasable connection upon connection of the first and second fuse body portions, wherein the first and second fuse assembly-receiving cavities together define an enclosure for enclosing an entirety of the fuse assembly when the first and second fuse holder components are connected to one another.
Optionally, the mateable, non-releasable connection components may comprise snap-fit components. The snap-fit components may comprise annular snap-fit components. Each of the first and second components may be a single, one-piece structure formed from thermoplastic rubber. Each of the first and second components may be formed from thermoplastic rubber having a hardness from about 50 Shore A to about 75 Shore A.
Moreover, the first wire receiving portion may configured for forming a substantially waterproof seal around the first wire when the first wire is inserted in the first wire receiving portion, and the second wire receiving portion may be configured for forming a substantially waterproof seal around the second wire when the second wire is inserted in the second wire receiving portion. Each of the first and second wire receiving portions may be configurable to selectively accommodate wires of different gauges.
A majority of a length of the enclosure may be defined by the first fuse assembly-receiving cavity. At least one of the first and second fuse holder components may include a plurality of internal, longitudinal ribs extending radially into the corresponding one of the first and second fuse assembly-receiving cavities.
The inline fuse holder assembly may be in combination with the fuse assembly including the fuse, and the first and second wire connectors at the respective first and second longitudinal ends of the fuse assembly. The fuse holder assembly may be in further combination with the first and second wires, wherein first and second connectors are connected to one another to form a substantially waterproof, non-releasable connection, and the fuse assembly is enclosed in the enclosure, wherein the first and second wires are electrically connected to the respective first and second wire connectors of the fuse assembly and extend through the respective first and second wire receiving portions to outside the respective first and second fuse holder components. The first wire receiving portion may form a substantially waterproof seal around the first wire, and the second wire receiving portion may form a substantially waterproof seal around the second wire. The inline fuse holder assembly may further includes a substantially waterproof, dielectric layer around the fuse and the wire connectors.
A method of assembling together a fuse assembly and fuse holder assembly is disclosed. The method includes inserting a first longitudinal end of the fuse assembly into a first fuse holder component of the fuse holder assembly, wherein the first fuse holder component is of a single, one-piece construction; and connecting a first connector of the first fuse holder component with a second connector of a second fuse holder component after inserting a first end of the fuse assembly, wherein the second fuse holder component is of a single, one-piece construction. A substantially non-releasable, waterproof connection between the first and second connectors is formed and entirety of the fuse assembly is enclosed in an enclosure defined by the first and second fuse holder components upon said connecting a first connector of the first fuse holder component with a second connector of a second fuse holder component.
Optionally, each of the first and second fuse holder components may be formed from thermoplastic rubber. The method may also include inserting a first wire into a first wire receiving portion of the first fuse holder component, wherein a portion of the first wire extends outside the first fuse holder component through a second longitudinal end of the first fuse holder component; connecting the first wire to a first wire connector of the first fuse assembly, wherein the first wire connector is disposed at a first longitudinal end of the fuse; inserting the second wire into a second wire receiving portion of the second fuse holder component, wherein a portion of the second wire extends outside the second fuse holder component through a second longitudinal end of the second fuse holder component; andconnecting the second wire to a second wire connector of the first fuse assembly, wherein the second wire connector is disposed at a second longitudinal end of the fuse.
Connecting the first wire to a first wire connector of the first fuse assembly may include crimping said first wire connector over said first wire, and connecting the second wire to a second wire connector of the second fuse assembly may include crimping said second wire connector over second first wire.
Another embodiment of an inline fuse holder assembly is also disclosed. The inline fuse holder was for enclosing a fuse assembly including a fuse, and first and second wire connectors at respective first and second longitudinal ends of the fuse assembly. The inline fuse holder includes a first fuse holder component having an open first longitudinal end and a second longitudinal end. The first component includes a first connector adjacent the first longitudinal end of the first fuse holder component, a first wire receiving portion adjacent the second longitudinal end of the first fuse holder component, and a first body portion intermediate the first connector and the first wire receiving portion. The first fuse holder component defines a first fuse assembly- receiving cavity, extending from the first longitudinal end toward the second longitudinal end and terminating before the first wire sealing portion, for receiving the first longitudinal end of the fuse assembly through the first longitudinal end of the first fuse holder component. The first wire receiving portion is configured for receiving a first wire connectable to the first wire connector when the fuse assembly is received in the fuse assembly-receiving cavity. A second fuse holder component has an open first longitudinal end and a second longitudinal end. The first component includes a second connector adjacent the first longitudinal end of the second fuse holder component, a second wire receiving portion adjacent the second longitudinal end of the second fuse holder component, and a second body portion intermediate the second connector and the second wire receiving portion. The second fuse holder component defines a second fuse assembly-receiving cavity, extending from the first longitudinal end toward the second longitudinal end and terminating before the second wire sealing portion, for receiving the second longitudinal end of the fuse assembly through the first longitudinal end of the second fuse holder component. The second wire receiving portion is configured for receiving a second wire connectable to the second wire connector when the fuse assembly is received in the fuse assembly-receiving cavity. Each of the first and second fuse holder components is of a single, one-piece construction of thermoplastic rubber, and at least one of the first and second fuse holder components includes a plurality of internal longitudinal ribs projecting into the corresponding one of the first and second fuse assembly-receiving cavity.
A fuse assembly formed as a single unit for use with a fuse holder assembly is also disclosed. The fuse assembly includes a ferrule fuse having opposite first and second longitudinal ends; a first wire connector at the first longitudinal end of the ferrule fuse for connecting the ferrule fuse to a first wire; a second wire connector at the second longitudinal end of the ferrule fuse for connecting the ferrule fuse to a second wire; and a substantially waterproof, dielectric outer layer surrounding the ferrule fuse and the first and second wire connectors.
Optionally, the ferrule fuse may include first and second ferrule terminals, and the first and second wire connectors may be crimped onto the respective first and second ferrule terminals and non-releasable connected thereto. The outer layer may comprise heat shrink.