US1968642A - Fuse - Google Patents

Description

July 31, 1934. c'. H. GUNTHORP FUSE Filed May 25, 1932 JnUeTiZFfT: C661] H Gard/10779- B Patented July 31, 1934 UlTED srrss PATENT OFFICE FUSE V I Cecil H. Gunthorp, Des Plaines, 111., assignor to Economy Fuse and Manufacturing (30., Chicago, 111., a corporation of New York Application May 23, 1932, Serial No. 612,932

17 Claims.

The present invention relates to electrical fuses and the like.

Among the objects of the present invention is to provide a novel fuse of relatively simple construction having few parts adapted to be easily assembled.

Another object of the present invention is to provide a novel fuse of the type used in electrical circuits for homes, ofiice buildings and the like,

in which a fusible element is inserted in an electrical circuit which is adapted to melt or burn to prevent damage to electrical equipment when a short circuit or overload occurs in the line or circuit.

In a fuse of the type herein referred to wherein the fusible element is enclosed within a chamber and visible through an opening provided in one of the elements of the fuse, it is very essential to provide a construction in which the arc, produced at the time of the short circuit in the line,

is extinguished before the same has had an opportunity to travel beyond the confines of the fuse in order to prevent fire hazards which would otherwise be present. It is also important to provide a construction in which the pressure of the gases formed as a result of the combustion of the fusible element at the time this short circuit occurs may build up to a point sufficient to extinguish the arc, but less than would be required to cause a bursting of the fuse. It is also essential to provide a fuse construction in which these hot gases resulting from the melting or combustion of the fusible element will be confined until the same are cooled, thereby rendering such a fuse safe for use in the vicinity of combustible ma terials which might otherwise catch fire and cause damage to the building in which the fuse is used.

Inasmuch as the gases which are produced upon a melting of the fusible element serve as conductors of electrical energy, it is important to break up this direct line of travel between the two terminals of the fuse between which these electrical charges might travel through the medium of these gases. In the present type of fuse,

this important item of construction has been overlooked, and even though the fusible element has been melted for breaking the circuit, electrical charges nevertheless may pass between these 56 spaced terminals as by means of the burned gases which act as conductors.

It is therefore an object of the present invention to provide a novel fuse wherein suitable means is provided for controlling the pressure built up within the chamber of the fuse for extinguishing.

the arc whereby the body of the fuse is not subjected to bursting pressures.

It is also another object of the present invention to provide a novel fuse in which suitable means is provided for controlling these hot gases produced upon a melting of the fusible element, whereby the same are confined within the fuse until cooled.

Another object within the purview of the present invention is to provide a novel fuse of such a construction wherein the various parts are so associated that electrical charges in the circuit cannot be transferred through thegases between the terminals of the fuse when the fusible element has melted to break the circuit.

Other objects, features, capabilities and advantages are comprehended by the invention, as will later appear and as are inherently possessed thereby.

Referring to the drawing:

Figure 1 is a view in cross section of a fuse made in accordance with the present invention;

Figure 2 is a view in cross section taken in a plane represented by line 22 of Figure l of the drawing; 30

Figure 3 is a fragmentary viewin cross section taken in a plane substantially represented by line 33 of Figure 2 of the drawing; and

Figure 4 is a view in perspective of the cap for the fuse shown in Figures 1 to 3 inclusive.

Referring now more in detail to the drawing, an embodiment selected to illustrate the present in vention is shown as comprising a base or body 2 which may have a substantially cylindrical por tion formedwith a chamber or cavity' l, and a tapered frusto-conical end part 6 having an opening (not disclosed) through which protrudes a terminal 8 adapted to engage with one end of a fusible element 10. This fusible element 10 extends toward the open end of the cylindrical part of the case or body 2 and has a central part extending across its opening in the form of spaced restricted portions 12, the other end of the fusible element 10 passing over the edge of the cylindrical part of the body 2 and being connected in any desired manner to a screw shell 14 which forms the other terminal for the fuse.

This screw shell 14 may be formed of any suitable material, and has an end formed with an inturned flange or spun portion 16 which is provided with a plurality of indented portions to provide protuberances 18. This screw shell 14 is provided with external threads adapted to have threaded engagement with a cap 20 internally threaded as at 22 for receiving the thread of the screw shell 14. In the present embodiment, the fuse is of the visible type and is provided with an opening 24 in the cap member 20 which is normally closed by a closure member 26 of any transparent or translucent material, such as mica or the like, which is adapted to be positioned between the inturned end 16 of the screw shell 14 and the apertured wall 23 of the cap member 20, this wall being formed with the open ing 24 whereby the fusible element 10 may be observed through this transparent closure member.

As previously indicated, the present invention is primarily concerned with the idea of controlling the gases formed within the chamber or compartment 4 when the fusible element 10 melts at the time of a short circuit in the line in which the same is provided. This controlling of the gases as well as the pressure thereof within the chamber 4 necessitates the providing of a suitable control outlet or passage from the chamber 4 to the atmosphere. In the present embodiment selected to illustrate the invention, this outlet or passage includes the opening 24. As clearly shown in Figure 4 of the drawing, the end wall 28 of the cap member 20 is formed with an inner series of raised portions or projections '30 between each of which portions is an opening, such as the opening 32. These'raisedportions or projeetions 30 are preferably concentric with the opening 24 and are spaced from a second series of raised portions or projections 34, between each or" whioh is an opening 36. It will be observed that theopenings 32 of the first series communicate with the channel or groove formed by the .wall 28 and the members of the first and second series, and the same are oppositely disposed in relation-to the members of the second series. Similarly, the openings 36 communicate with this channel or passage between the series of projectienswand are oppositely disposed in relation to the members of the inner series. It will therefore be obvious that the arrangement of these series one to the other provides bafiling means for interrupting the passage of gases through the open n s 36 a d t i te med passa b tween the mernbers of the series through the openings 32 through the opening 24 into the atmosphere. The closure member 26 is of a diameter less than the diameter of the threaded opening for the 02p 20, and the same is held in association with the projections formed on the cap 20, as by means of the screw shell 14, which may bese-rewed into engagement therewith. The protuberances 18 heretofore referred to engage with the closure member 26 for maintaining this closure member in spaced relation to the end of the screw-shell 14, whereby gases may pass outwardly fromthe chamber 4, between these pro tuberances 18, around the edge of the closure member 26 and through the tortuous passages providedby the series of projections 30 and 34.

"In securing the screw shell to the cap, the same may be effected by providing staking holes or recesses 38in spaced relation in thewall 28 of a the cap and staking portions 40-into these staking holes or recesses, as by means of a staking tool,

th re y preventin th un w h p from the screw shell.

As hereinbefore referred to, the present invention also. contemplates the idea of providing a constru'ctionin a fuse in which there is no danger of the are forming between the terminal 8 and the screw shell which acts as another terminal through the medium of the gases of combustion formed at the time of melting of the fusible element, which gases serve as a conductor. This is prevented in the present embodiment as by providing the end of the cylindrical part of the casing or body 2 with an annular recess 42 which is adapted to receive the spun or inturned end 16 of the screw shell 14. With this construction, it will be clearly apparent that when the body member 2 is in the position as shown in Figures 1 and 3 of the drawing, the spun or inturned end 16 of the screw shell is separated from the chamber 4 as by means of the shoulder 44 formed by the recess 42. Inasmuch as the screw shell 14 is connected to one end of the fusible element 10 and serves as a terminal for this fuse, this shouldered construction for the cylindrical part of the case or body 2 prevents any possibility of an arc jumping between the inturned or spun end 16 of this screw shell and the terminal member 8 which has a part projecting into the chamber 4 and connected to the, other end of the fusible element 10.

It will also be clearly apparent that the series of projections 30 and 34 are so arranged as to act as bailies to provide tortuous passages for the gases formed in the chamber 4, and it is of course understood that the same may be arranged in any desired manner for suitably controlling these gases to keep the same confined until cooled, as likewise to control the pressure built up within the chamber 4.

In forming this fuse, thebody or casing ,2 is inserted within the screw shell, after the latter has been staked in place within the cap 20 and the end 46 of the screw shell spun inwardly, as disclosed in Figure 1, to engage with the shoulder 48 adjacent the frusto-conical end 6 for maintaining this body or casing in positiontherein. In order to prevent twistingand turningof the body or casing 2 within the screw shell 14, the shoulder 48 may be formed with staking .holes or recesses 50, and portions 52 of they spun or 111-" turned end 4.6 of the screw shell 14 may be pressed therein, as by means of a staking tool.

While I have herein describedand upon the drawing shown an illustrative embodiment of the invention, it is to be understood that the invention is not limited thereto but may Comprehend other constructions, arrangements of parts, details and features without departing from the spirit of the invention.

I claim:

1. In an electrical fuse, the combination of a body member having a chamber provided with an open end, a fusible element in said chamber, a cap associated with said member, said cap having an'apertured end wall oppositely disposed in relation to said chamber, a closure member interposed between said wall and said body mem her and of material whereby said fusible element is visible, said closure member having its edge in spacedrelation with said cap, and means for positioning said last-named member in spaced relaticn with the wall forming the open end of said body member and said cap to provide a passage for gases from said chamber through said opening into the atmosphere.

2. In an electrical fuse, the combination of a body member having a chamber provided With an open end, a fusible element in said chamber, a cap associated with said member, said cap having an apertured end wall oppositely disposed in relation to said chamber, a closure member interposed between said wall and said body member and ofmaterial whereby said fusible element is visible,

i relation with said cap,

I relation with said cap,

I having a chamber,

said closure member having its edge in spaced relation with said cap, and means for positioning said last-named member in spaced relation with the wall forming the open end of said body member and said cap to provide a passage for gases from said chamber through said opening into the atmosphere, said means including members pros jecting from said wall.

3. In an electrical fuse, the body member having a chamber open end, a fusible element in said chamber, a cap associated with said member, said cap having an apertured end wall oppositely disposed in relation to said chamber, a closure member interposed between said wall and said body member and of material whereby said fusible element is visible, said closure member having its edge in spaced relation with said cap, and means for positioning said last-named member in spaced relation with the wall forming the open end of said body member and said cap to provide a passage for gases from said chamber through said opening into the atmosphere, said means including members projecting from said wall and spaced apart radially combination of a provided with an from said aperture.

4. In an electrical fuse, the combination of a body member having a chamber, a fusible element in said chamber, a cap associated with said member, said cap having an apertured end wall l oppositely disposed in relation to said chamber and side walls, a closure member interposed between said wall and said body member and of material whereby said fusible element is visible, said closure member having its edge in spaced and means for positioning said last-named member in spaced relation with said body member and cap to provide a passage for gases from said chamber through said opening into the atmosphere, said means including a series of spaced members projecting from said wall, and a second series of spaced members spaced from said first-named series and side walls of said cap and being disposed in opposite relation to the openings between the members of said I first series.

5. In an electrical fuse, the combination of a body member having a chamber, a fusible element in said chamber, a cap associated with said member, said cap having an apertured end wall i oppositely disposed in relation to said chamber and side walls, a closure member interposed between said wall and said body member and of material whereby said fusible element is visible, said closure member having its edge in spaced and means for positioning said last-named member in spaced relation with said body member and cap to provide a passage for gases from said chamber through said opening into the atmosphere, said means including a series of spaced members projecting from said wall and concentrically arranged in relation to said aperture, and a second series of spaced members spaced from said first-named series and concentrically arranged therewith in oppositely disposed relation to the openings between the members of said first series and in spaced rela tion to said side walls.

6. In an electrical fuse, the combination of a screw shell, a body member fitting therein and a fusible element in said chamber, a cap member secured to said screw shell and having an opening oppositely disposed in relation to said chamber, a closure member for H said opening and of material whereby said fusible element is visible, said closure member having its said body member and cap edge in spaced relation to said cap member, said shell and cap member having means for positioning said closure member in spaced relation to said body member and cap member 'to provide a passage for gases from said chamber through the opening into the atmosphere.

'7. In an electrical fuse, the combination of a screw shell, a body memberfitting therein and having a chamber, a fusible element in said chamber, a cap member secured to said screw shell and having an opening oppositely disposed in relation to said chamber, a closure member for said opening and of material whereby said fusible element is visible, said closure member having its edge in spaced relation to said cap member, and projections on said shell and cap member for positioning said closure member in spaced relation to member to provide a passage for gases from said chamber through the opening into the atmosphere.

8. In an electrical fuse, the combination of a screw shell, a body member fitting therein and having a chamber, a fusible element in said chamber, a cap member secured to said screw shell, said cap having an apertured end wall oppositely disposed in relation to said chamber, a closure member for said aperture and of material whereby said fusible element is visible, said closure member having its edge in spaced relation to said cap member, and projections on said shell and wall for positioning said closure member in spaced relation to said body member and cap member to provide a passage for gases from said chamber through the aperture into the atmosphere.

9. In an electrical fuse, the combination of a screw shell, a body member fitting therein and having a chamber, a fusible element in said chamber, a cap member secured to said screw shell, said cap having an apertured end wall oppositely disposed in relation to said chamber, a closure member for said aperture and of material whereby said fusible element is visible, said closure member having its edge in spaced relation to said cap member, and projections on said shell and wall for positioning said closure member in spaced relation to said body member and cap member to provide a passage for gases from said chamber through the aperture into the atmosphere, the projections on said wall being in staggered relation to provide a tortuous passage for said gases.

10. A screw shell for an electrical fuse, comprising a member having an end formed with an inturned flange, said flange having a plurality of indented portions providing outwardly projecting protuberances.

11. A cap for an electrical fuse, comprising a member having an apertured wall and side wall, and radially spaced members projecting from said apertured wall and spaced from said side wall.

12. A cap for an electrical fuse, comprising a member having an apertured wall and side wall, and spaced members projecting from said aper tured wall and spaced from said side wall, said members being in staggered relation.

13. A cap for an electrical fuse, comprising a member having an apertured wall and side wall, a series of spaced members projecting from said wall and concentrically arranged in relation to said opening, and a second series of spaced members spaced in relation to said first-named series and said. side wall and being oppositely disposed in relation to the openings between the members of said first-named series.

14. In an electrical fuse, the combination of a screw shell, a body member fitting therein and having a chamber formed by a wall, said wall having an end provided with a recess spaced from the inside face of said wall and said chamber, said screw shell having a fiangedisposed in said recess, a fusible element in said chamber, a cap member secured to said screw shell, said cap having an apertured end wall oppositely disposed in relation to said chamber, a closure member for said aperture and of material whereby said fusible element is visible, said closure member having its edge in spaced relation to said cap member, means for holding said closure member in spaced relation to said apertured wall and said screw shell and the wall of said body member.

15. In an electrical fuse, the combination of a screw shell, a body member fitting therein and having a chamber formed by a wall, said wall having an end provided with a recess spaced from said chamber, said screw shell having a flange disposed in said recess, a fusible element in said chamber, a cap member secured to said screw shell, said cap having an apertured end wall oppositely disposed in relation to said cham ber, a closure member for said aperture and of material whereby said fusible element is visible,

said closure member having its edge in spaced relation to said cap member, and projections on said shell and wall for positioning said closure member in spaced relation to said body member and cap member to provide a passage for gases from said chamber through the aperture into the atmosphere.

16. In an electrical fuse, the combination of a screw shell, a cap member embracing said screw shell and having an end wall formed With an aperture, said end wall having spaced projections and a depressed portion, and a closure member between said screw shell and projections, said screw shell having a portion staked into said depressed portion for securing said shell, cap and closure members together and to prevent relative movement.

17. In an electrical fuse, the combination of a screw shell, a cap member embracing said screw shell, a body member fitting within said screw shell, said screw shell having flangesembracing said body member, one of said flanges having a portion staked to engage said body portion and the other of said flanges having a portion staked to engage said cap member whereby said members are prevented from turning.

CECIL H. GUNTHORP.

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