US 2405929 A
Description (OCR text may contain errors)
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fi'orneg I Patented Aug. 13, 1946 ELECTRICAL APPARATUS Gerson E. Wald, Far Rockaway, N. Y., assignor to Bendix Aviation Corporation, Bendix, N. J., a
corporation of Delaware Application June 9, 1943, Serial No. 490,196
This invention relates to electrical apparatus, and particularly to the application of indicating means to electrical circuits, to indicate the condition of fuses controlling flow of current there- An object of the invention is to indicate electrically the condition of fuses employed in electric circuits.
Another object is to provide an electrical fuse of novel construction, which novel construction permits the fuse to function as the means for actuating electrical means to indicate when the fuse has blown.
Another object is to provide means to indicate when a fuse has been removed from the circuit to which it is applied; the same means also functioning to indicate a blown fuse.
These and other objects of the invention will become apparent from inspection of the following specification when read with reference to the accompanying drawings wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawings are for the purpose of illustration only, and are not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.
In the drawings:
Fig. 1 is a view partly in section, partly in elevation, and partly schematic, of apparatus embodying the invention;
Fig. 2 is a sectional view along line 2'2 of Fig. 1;
Fig. 3 is a view similar to Fig. 2 but showing the relative positions of the parts when a fuse has blown;
Fig. 4 is a sectional view along line 44 of Fig. 2 and also includes a showing of the fuse holder detached from the fuse board;
Fig. 5 is a perspective view of the parts shown in Fig. 4;
Fig. 6 is another perspective view of the fuse holder;
Fig. '7 is a perspective View of the fuse clip assembly for two fuses;
Fig. 8 is a view in perspective of a second embodiment of the invention;
Fig. 9 is a schematic representation of the electrical connections involved when the form of the invention shown in Fig. 8 is employed;
Fig. 10 is a View similar to Fig. 9 but showing the circuit closed by the blowing of one fuse;
Fig. 11 is a View similar to Figs. 9 and 10 but showing the circuit closed by the removal of one or more fuses from their operative positions on the fuse board; and
Fig. 12 is a schematic showing of a modified circuit wherein there is a signal element individual to each fuse.
In Figs. 1 to 7 reference characters 16, ll, i8 and I9 designate fuses adapted to be held in electrical contact with fuse clip fingers, thos for fuse I9 being numbered 2|, 22, 23 and 24. As shown in Figs. 2 and 3, each fuse is of novel construction, including an apertured upper end receiving a plunger of the series shown at 26, 27, 28 and 29 in Fig. 1, said plunger 29 being engaged by the head 3! of a fusible wire rod 32 extending centrally-through the fuse l9 and secured at the base of the fuse, as shown at 33. A cap 31 is urged upwardly from spring seat 38, by a spring 39, and when the fusible wire 32 breaks, due to excessive electrical heating, the spring 39 snaps the cap 37, wire head 31 and plunger 29 upwardly (see Fi 3) thereby tilting the plunger carrying strip 4! in such a direction as to actuate the plunger 42 (Fig. 1) of the microswitch 43-the said micro-switch 43 being of any snap-action type well-known in the art, as, for example, the type shown in McGall Patent No. 1,960,020, granted May 22, 1934.
A flexible metallic strip 46 is anchored at one end to the switch housing, as in conventional micro-switch construction, and its other end carries the non-conducting strip 4| the whole being suspended from the switch housing which in turn is screwed to the fuse panel 48, or a bracket thereon.
Fuse holders 5| and 52 are shown as carrying the fuses IE to l9, there being two fuses for each holder. Each holder has a ledge 54 and a central boss 53 apertured to receive the fuses, and also recessed to receive the conical head 55 of the fuse block 56, the latter being fastened to panel 48. These parts 53, 55 and 54 cooperate to position and retain the fuses in proper relation to the fuse clips.
From the foregoing disclosure, it is apparent that, should any one of the four fuses become blown, for instance fuse l9, its plunger 3i will be moved up under the influence of spring 39 into the position shown in Fig. 3 which through plunger 29 rocks insulated strip 4| upwardly. This, through plunger 42 closes the micro-switch 43 which completes the circuit of lamp 44 which gives a visible signal showing that one or more of the four fuses has blown. The invention also may assume a form in which removal of any of the fuses from the holding clips is also operable 3 to energize the indicator circuit. This mcdification of the invention will now be described.
In Figs. 8 to 11 each fuse block is equipped with levers (see levers 6 l, 62 in Fig. 8) ivoted to the sides of the block, as at 63 and E4, and urged downward by springs 66, 61, the latter being anchored to the block at ll, '52. Each lever is of insulating material, but each carries a metal bar 73, M, engageable with the fuse clip tips of the adjacent fuse clip (as indicated at 8!, 82, 83 and 64 in Fig. 11) when urged downward by springs '56, 6'! in the absence of the fuses. the fuses will automatically thrustthe levers M, 62 backwardly due to the resulting physical" interference between central bulge 553 on the one hand and the sloping edges of levers ill, (52 on the other, thus causing metal bars l3, id to move back and up, into the relative positions, with. respect to fuse clip tips, that are indicated in Fig. 9. In the Fig. 11 positions of metal bars l3, '14, parallel circuits are closed to energize signal lamp 9! (or separate signal lamps 93, as, in the arrangement of Fig. 123 while in Fig. 9' thelamp is extinguished, due to the open condition ofboth branches of the circuit.
In the eventof a blown fuse, as at I? in Fig. 10, the fusible wire head 3! (as in Figs. 2'and 3) will be pushed up into contact with the. bar 13', thus closing the circuit to light the lamp 91, in lieu of the micro-switch ofFig. 1v
What'is claimed is:
1. In an electrical apparatus, a plurality of fuses operable to limit the current flow in severalcircuits, each fuse comprising a fusible element and means for axially displacing one end of Insertion of 4 said element in response to fusion thereof, an auxiliary circuit containing an electrically energized signal device, a normally open switch disposed in operative relationship to said fuses and operable to control said circuit, and means coacting with said switch and the fusible elements of all of said fuses for causing said switch to close and energize said signal device when any of said fusible elements are displaced axially, said last named means comprising an arm mounted for rocking movement and carrying a plurality of membersaligned with. and engageable by any one of the fusible elements of. said fuses.
2. In an electrical apparatus, a plurality of fuses operable to limit the current flow in several circuits, each fuse comprising a fusible element and-means for axially displacing one end of said element in response to fusion thereof, an auxiliary circuit containing an electrically energized signal device, a normally open switch disposed in operative relationship to saidfuses and operable to control'said circuit, and means'coa'cting with saidswitch and the" fusibleel'ements' of all of said fuses for causing said switch to close and energiz said signal device whenany of said fusible elements are displaced axially, said normally open switch comprising a switch of the microsnap action type having a plunger adapted to close the switch upon minute movement thereof, andsaid means coacting with said'switch comprising an arm mountedfor'rockingmovement and operable to move said plunger into switch closing position upon projection of, the fusible element'of anyone of said fuses.