US1887281A - Fuse - Google Patents

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US1887281A
US1887281A US451722A US45172230A US1887281A US 1887281 A US1887281 A US 1887281A US 451722 A US451722 A US 451722A US 45172230 A US45172230 A US 45172230A US 1887281 A US1887281 A US 1887281A
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fuse
chuck
insulator
tube
jaws
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US451722A
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Blomquist Ernst
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Individual
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/10Adaptation for built-in fuses
    • H01H9/102Fuses mounted on or constituting the movable contact parts of the switch

Definitions

  • each jaw of the chuck are preferably made to concontaining toe necessary switching equlpform with the contour of the ferrule so as 15 ment arranged in a very compact manner. to obtain a firm grip thereon and to make In certain circuits fuses are used and where good electrical contact therewith.
  • the chuck a compact arrangement is desired the locais made of metal of high conductivity and tion and mounting of the fuses must receive constitutes the terminal for establishing a cirspecial attention.
  • the fuse used may be a uit through the ferrule to the fuse.
  • the fuse is first mounted in the chuck and is lVhen such a fuse blows under very heavy inserted through the tube of insulating mashort circuiting conditions it frequently terial and into engagement with the contact shatters the glass tube and if it is in the imclips by manually gripping the handle of mediate vicinity of grounded or live parts the removable member and plunging the fuse :10 there is adanger of establishing an arc to into the stationary member. WVhen the fuse those parts. This is, of course, an occurrence is fully inserted in place the upper contact which must be prevented under all condiclip engages the upper ferrule and the lower tions. To prevent this occurrence it has contact clip engages the chuck, thus connectbeen customary, in the past, to allow a coning the fuse in circuit.
  • the fuse including the ferrules and the glass Should the terminal clips happen to be alive tube containing the insulating liquid and the during these operations and should the chuck fusible element may be inserted.
  • the fuse holder in two parts, provide an interlocking arrangement for preone of which is stationary, being rigidly venting the insertion or removal of the fuse mounted, and the other of which is removwhile the terminal clips are connected in cirable, being the part provided for manipulatcuit.
  • grounding means for grounding the portion of the fuse holder adjacent the handle when the same is at or near the position that it occupies when the fuse is in place. This comprises a metallic plate interposed between the handle and the chuck holding insulator and a number of grounding spring contacts which engage the plate as the same approaches the position that it occupies when the fuse is in place.
  • Fuses of the type here shown are provided with a vent cap which is adapted to be blown out when the fuse is blown by a heavy short circuit. It is necessary that the fuse be mounted with this vent cap directed upwardly.
  • Figure 1 is a partial longitudinal section of my improved fuse holder
  • Figure 2 is a partial longitudinal section of the upper contact clip of the fuse holder
  • Figure 3 is a partial longitudinalsection of the lower contact clip
  • Figure 4 is a partial longitudinal section of the chuck forming a part of the fuse holder
  • Figure 5 is a sectional view taken along the line 55 of Figure 4 and looking in the direction of the arrows;
  • Figure 6 is a sectional View taken along the line 66 of Figure 4; and looking in the direction of the arrows;
  • Figure 7 is a side view of a box within which the fuse holder is mounted, said view being taken with the side cover of the box re moved;
  • Figure 8 is a front View of the fuse and switch box shown in Figure 7.
  • FIG. 1 of the drawings showing my novel form of fuse holder.
  • my fuse holder for use in connection with what is now known as a Schweitzer and Conrad type of fuse, such as is disclosed for example in the patent of glass or the like having terminal ferrules 11 and 12 at its opposite ends, the fuse element being located within the body of the fuse and surrounded by a body of insulating liquid of high are extinguishing properties for quenching any are that may form upon the blowing of the fuse.
  • the fuse holder is indicated in general by the reference numeral 15 and comprises an insulator member 16 of a generally tubular form which is secured by means of a bracket 17 to the wall of a cabinet such as is shown '11 Figures 7 and 8. It is however to be understood that this fuse holder may be mounted in a manner other than that here shown and need not necessarily be located in a cabinet such as is shown in Figures 7 and 8.
  • An internally threaded copper tube 19 to which an upper terminal member 20 is soldered or otherwise suitably secured is itself suitably cemented in the top of the insulator 16.
  • a tube 21 of copper or other suitable metal for high conductivity is threaded into the tube 19.
  • the tube 21 is shown more particularly in Figure 2 and is provided with external threads 22 that thread into the internally threaded member 19.
  • Bronze spring contact clips 2A are soldered at 25 on the outside of the tube 21 and are bent up within the tube, the ends 26 of these springs being free.
  • the spring contact clips 24 are inwardly bowed as may be seen from Figures 1 and 2 and they engage the upper ferrule 11 of the fuse and establish an electric circuit between the terminal 20 and the fuse through the members 21 and 19.
  • the member 21 is provided with two screw driver slots indicated at 27 to facilitate the insertion and removal of that member from the tube 19.
  • the fuse holding or gripping portion of the fuse mounting comprises an insulator 30 into the iottom of which is cemented or otherwise suitably secured an internally threaded member 31 forreceiving the handle.
  • the handle comprises a gripping member 32 of wood or other suitable insulating material and having a steel shank 33 secured therein. The upper portion of the steel shank is screw threaded and it threads into an opening in the member 31.
  • a plate 35 of brass or other suitable conducting metal is interposed between the top of the handle 32 and the bottom of the member 31, a lock washer 36 being located between the brass disc or plate 35 and the member 31 for holding the handle and the disc 35 rigidly QR.
  • a mounting in .nber 40 Similar to the member 31 is cemented within the top of the insulator 30 and is internally threaded to receive the end of a chuck such as is shown more fully in Figure 4.
  • the chuck comprises a threaded shank or stem member 45 slotted at the top to receive a bar 46, said bar being pivoted to the shank 45 by means of a pivot pin 47 so as to allow a limited amount of swinging movement of the bar or lever 46.
  • Two chuck aws 48 and 49 are pivoted to the lever rod 46 by means of pins 50 and 51 respectively.
  • the two chuck jaws 48 and 49 are slotted at their lower ends as indicated at 53 to permit a swinging movement of the aws about the pivot pins 50 and 51 respectively, the lever 46 swinging in those slots during this movement of the jaws.
  • the two chuck jaws are adapted to receive the lower fuse ferrule 12 between them and they are provided on their inner sides with a shoulder at their lower end to limit the downward movement of the ferrule and with a shoulder 61 at their upper end to limit the upward movement of the ferrule.
  • the inner surface of the chuck jaws between these two shoulders is of a generally cylindrical shape and the lower fuse ferrule 12 fits snugly within the jaws between the shoulders whereby the aws of the chuck establish good electrical contact with the ferrules.
  • the jaws of the chuck are made of metal having a high conductivity whereby the chuck jaws may act as a terminal for the fuse.
  • a chuck tightening and loosening ring member 65 which has a cone-shaped upper portion 66 and which is freely slidable upon the shank or stem 45. WVhen the stem 45 is threaded into the threaded hole in the mounting member 40 in the top of the insulator 30,
  • the ring member 65 lies between the top of the mounting member 40 and the bottom of 'i the chuck jaws 48 and 49.
  • the shank or stem 45 is normally threaded into the mounting member 40. As the same is threaded further and further into the mounting stem the bottom edge of the chuck i jaws 48 and 49 are brought closer and closer to the ring 65. Prior to their engagement with the ring these jaws are free to swing about their pivot pins 50 and 51 extending through the lever 46 and likewise the lever 46 is free to swing about its pin 47. This means that the jaws are free to open at their upper ends, that is at their ends above the pivoted lever 46.
  • the cone portion 66 enters into the space between the two chuck jaws and limits the extent to which the jaw 49 may swing in a clockwise direction and the extent to which the jaw 48 may swing in a counter-clockwise direc tion. This means that it limits the extent of opening movement of the portion of the jaws above the lever 46.
  • the stem 45 is unthreaded a certain amount from the mounting member 40 so as to permit an opening of the jaws sufficient for the insertion of the lower fuse ferrule 12 between the jaws. The lower fuse ferrule 12 is then inserted between the jaws until the bottom of the fuse ferrule rests upon the shoulder 60.
  • the stem 45 is then threaded further into the mounting member 40. WVhen this is done the conical shaped portion 66 of the ring 65 is forced upward between the lower portion of the chuck jaws thereby forcing the lower portions of the jaws to swing outwardly about the pivot pins 50 and 51 and thus to force the upper portion of the jaws to swing inwardly, thereby firmly gripping the fuse ferrule that is between these jaws.
  • the pivoted bar or lever 46 equalizes the extent of movement of the two chuck jaws.
  • the spac ing between the shoulders 60 and 61 is made equal to the length of the lower fuse ferrule so that the chuck maintains a firm grip upon the fuse.
  • the handle 32 of the fuse hol-r is then gripped by hand and the fuse and the bottom portion of the fuse holder, namely the insulator 30, are inserted through a grounded shield 68, of which more will be said as the description proceeds.
  • the fuses passes through the insulator 16 until the upper ferrule 11. is engaged by the spring contact clips 24. At this time the outer surfaces of the chuck jaws engage a lower terminal clip 70 which is of a construction similar to the terminal 21 and which is shown more fully in Figure 3, which is electrically connected to a line terminal 71. The fuse thus establishes a circuit between the terminals 20 and 71 of the fuse holder.
  • the lower fuse terminal clip '70 which secured within the insulator 15 comprises a ring 75 of copper or the like, which is internally threaded adjacent its upper portion which is cemented or otherwise suitably cured within an enlarged bore in the lower portion of the insulator 15.
  • a line terminal 71 is soldered or otherwise suitably electrically secured to the ring member 75.
  • the ring 7 5 is adapted to receive a ring 76 of a construction such as is shown more particu larly in Figure 3.
  • the ring 76 comprises a tube of copper or the like which is threaded at its upper portion as indicated at 77 and is provided with a number of spring contact clips 78 that extend on the inside thereof for engaging the outer surface of the jaws of the chuck.
  • the spring clips 7 8 on the inner side of the tube member 76 are bent back and under the tube, the ends 79 of these springs being secured in intimate contact with the wall of the tube. I have shown a preferred manner of obtaining this intimate contact. This comprises a ring'or collar 80 that is pressed onto the bottom of the member 76 on the outside ofthe spring.
  • This collar forms a rather tight fit with the spring and is held in place by a number of screws 81 that extend through the collar and are threaded into suitably tapped holes in the member 76.
  • the bottom of the member 76 may be provided with. a number of slots through which the spring contact clips 7 8 extend sothat the bottoms of these contact clips are flush with the bottom of the member 7 6 and the ring or collar 80 is provided with an inwardly extending shoulder portion that fits over the bottom of the member 76.
  • the spring clips are bowed inwardly toward the center of the ring member 7 6 and are free at their upper ends, these ends bearing against the cylindrical inner surface of the ring mem ber 76.
  • the contact clip springs 78 are enabled to maintain firm spring contact against the outer cylindrical wall surfaces of the chuck members 4:8 and 49.
  • the upper ferrule is provided with an explosion cap which is adapted to be blown outwardly )y the explosion within the fuse chamber when the fuse therein interrupts a current of magnitude. For this reason it is therefore essential that the fuse be mounted with its ferrule 11 in the upper position.
  • the forrule 11 is slightly longer than the ferrule 12 and it will therefore not fit into the space between the two shoulders and 61 of the chuck.
  • a cap 85 preferably of asbestos or other suitable insulating material capable of with standing high temperatures is secured to the insulator 1.6 by means of number-of strips 86 and a strap clamp 87 which is clamped around the insulator 16, the ends of the strap 87 being bolted or otherwise secured together 88.
  • the cap 85 is supported in spaced relationship from the insulator 16 by the str'ps 86, a plurality of these strips being prov W...
  • the asbestos cap 8? is provided in order to stop an arc that may be formed by a Violent explosion of the fuse and which might otherwise tend to go to ground t the top of the cabinet within which the fuse holder is mounted.
  • the fuse and with it the insulator portion 80 and the handle 32 is passed through a grounded shield 68 to insert the same in position within the insu later 16.
  • This shield is mounted within the fuse cabinet wherein the insulator 16 is mounted, the shield being spaced from that insulator as shown in the drawings.
  • the shield is provided with a number of spring wire contact clips 90 secured on the inside thereof and spaced from one another by small amounts.
  • Each of the spring contact wires 90 is provided with a shoulder 91 adjacent its upper end.
  • the fuse holder shown is not only simple and turdy in construction but is exceedingly safe to manipulate, for when the operator grasps the handle 32 to remove the fuse, or to insert the same into place, the grounded shield 68 and the grounded disc 35 render it impossible for the operator to come into contact with electrically alive parts. Should the insulator 30 become defective the operator would still be protected since the parts adjacent the handle 32 are grounded.
  • FIG. 7 and 8 showing a cabinet within which a fuse holder such as is shown in Figure 1 is mountcd.
  • a fuse holder such as is shown in Figure 1 is mountcd.
  • This is shownfor illustrative purposes and it is to be understood that the fuse holder may be mounted in specifically different l'cinds of cabinets.
  • "he cabinet comprises a substantially rectangular metallic box 100 which may be of any approved construction.
  • the cabinet shown in Figure 7 is adapted for use on three-phase systems, although it may be used on other systems, and has mounted therein a triple pole double throw switch 105, One pole being provided for each phase.
  • the conductors from the conduit 103 extend to one set of terminals, indicated at 106, and the conductors from the conduit 102 extend to the opposite terminals 107 of the three pole switch.
  • the blades 108 of the switch are pivoted at 109 and are adapted to selectively engage either the terminals 106 or the terminals 107.
  • There are three fuse holders such as the fuse holder 15 of Figure 1 mounted within the cabinet, one fuse being provided for each phase. The fur are mounted in spaced relationship, one of these fuses being seen in Figure 7, the other two being directly behind the one there soon.
  • the fuse holder i shown as mounted in an inclined position and is adapted to have the fuse inserted therein through the side wall 115 of the cabinet.
  • the side wall is provided with a door 116 which is hinged to the wall 115 by means of hinges 117 and 118.
  • a pipe member 120 is pivoted between the pivots 121 and 122 and is provided with a portion 123 which overlies the door 116 and when in that position it prevents opening of the door and thereby prevents the insertion or removal of a fuse from the fuse holder.
  • a rod 125 is provided for manipulating the pipe 120 to swing the same into or out of position in front of the door 116.
  • This rod 125 is connected to suitable interlocking means (not shown) for preventing the opening of the door 116 while the circuit to the opposite terminals of the fuse is closed.
  • the shields 68 for the three fuse holders are shown in dotted lines in Figure 8, these shields being cut off at an angle in order to permit mounting of the fuse holder in an inclined position.
  • a handle 130 is provided for operating the triple pole double throw switch 105. This handle is connected to rotate the shaft 131 which rotates a set of crank arms 132 which act through a set of insulating rods 133 to actuate the blades 108 of the switch.
  • the rods 133 may be made of bakelite or any other suitable insulating material.
  • the upper terminals 20 of the fuse holder are connected to the central clips of the respective poles of the three pole switch 105 and the lower terminals 71 of the fuse holder are connected to conductors which 8X- tend from the switching cabinet through the conduit 101.
  • a fuse holder comprising a grounded metallic tubular member, grounded spring clips within the member, a fuse holding insulator insertable through said tubular member, a fuse receiving chuck mounted at one end of the insulator, a handle mounted at the other end thereof and a metallic plate interposed between the handle and the insulator, said plate resting upon and being removably supported by the spring clips when the fuse holding insulator is inserted through the tubular member.
  • a fuse holder comprising a grounded metallic tubular member, grounded spring clips within the member, a fuse holding insu lator insertable through said tubular member, a fuse receiving chuck mounted at one end of the insulator, a handle mounted at the other end thereof, and a metallic plate interposed between the handle and the insulator, said plate resting upon and being removably supported by the spring clips when the fuse holding insulator is inserted through the tubular member, said grounded tubular member being of a diameter suflicient to permit the free entry of a hand therein to grip the handle.
  • a fuse holder comprising a block of insulation, a fuse receiving chuck mounted on one end of the block, a handle mounted on the other end of the block, and a grounding plate interposed between the handle and the insulation.
  • a fuse holder comprising an insulator, a fuse receiving chuck mounted on one side of the insulator, a handle mounted on the other side of the insulator, a metallic plate interposed between the insulator and the handle, and a short grounded metallic tubular member surrounding the fuse holder at the handle and being of a diameter to permit the free entry of a hand therein to grip the handie and withdraw the fuse holder, said tubular member being in electrical contact with said plate.
  • a fuse holder comprising an insulator, a fuse receiving chuck mounted on one side of the insulator, a handle mounted on the other side of the insulator, a metallic plate interposed between the insulator and the ban dle, and a short grounded metallic tubular member surrounding the fuse holder at the handle and being of a diameter to permit the free entry of a hand therein to grip the handle and withdraw the fuse holder, and spring means for maintaining electrical contact between the tubular member and said plate.
  • current flow interrupting means having a terminal portion at one end, an insulator, means for gripping one end of the insulator, and a chuck at the other end of the insulator for gripping the terminal portion of the current flow interrupting means, the chuck constituting the means for cal establishing a circuit through the interrupting means, and including means for tighten ing the chuck against the terminal, said last means being controlled by rotation of the insulator with respect to the chuck.
  • Switching means comprising a tube of insulation, contact clip members on the inside of the tube, means for mounting the tube in a generally vertical position, current flow interrupting means having terminal members at its opposite ends, conducting means for gripping one of the terminalsof said first means and thus supporting said first means, said current flow interrupting means being within the tube of insulation with its other terminal member in. engagement with one of the contact clips and with said conductive gripping means in engagement with the other clip, thus establishing a circuit between said clips, the upper end of the current flow interrupting means being expellable, and an insulating cap mounted on the tube and spaced above the upper end thereof.
  • Switching means comprising a tube of insulation, means mounting the same in a generally vertically extending position, a pair of contact clip members mounted on the inside of the tube, a fuse comprising an outer tube having ferrules at the opposite ends thereof and a fusible element therein connected between the ferrules, means for gripping one of the ferrules of the fuse, said fuse tube being of an outside diameter appreciably smaller than the inside diameter of the first tube and being within the first tube, said last named means being in engagement with one of the contact clips and the opposite ferrule being in engagement with the opposite contact clip, the upper ferrule including an expellable cap, and said outer tube of insulation being open at the tip to permit expulsion of the products of a circuit interruption.
  • Switching means comprising a tube of insulation, a pair of contact clip members mounted on the inside of the tube, a fuse comprising an outer tube having ferrules at the opposite ends thereof and a fusible ele ment therein connected between the ferrules, means for gripping one of the ferrules of the fuse, said fuse tube being of an outside diameter appreciably smaller than the inside diameter of the first tube and being within the first tube, said last named means being in engagement with one of the contact clips and the opposite ferrule being in engagement With-the opposite contact clip, said means for gripping the ferrule of the fuse having means associated therewith for locking itself to the ferrule for inserting and removing the fuse from the first mentioned tube.
  • a fuse holder comprising a pair of arms pivoted intermediate their ends and adapted to receiveafuse between them at one end, means adjacent the other ends of the arms for spreading those ends apart thereby forcing the opposite ends towards one another into gripping relation to the fuse, means for holding the fuse holder, said means including a handle and insulation between the handle and the pair of arms, and an insulating tube into which the fuse is adapted to be inserted by the holder, said tube including contact means which engage the pivoted arms and establish a circuit there through.
  • a chuck including a pair of gripping jaws adapted to grip an electrical device, screw threaded means for tightening the jaws to clamp the device, means for holding the chuck, said means comprising a handle insulated from the chuck, and grounding means interposed between the handle and the chuck and also insulated from the chuck.
  • a chuck including a pair of gripping jaws adapted to grip an electrical device, screw threaded means for tightening the jaws to clamp the device, means for holding the chuck, said means comprising a handle insulated from the chuck, and means for extending a circuit to the chuck and through it to an electrical device held therein, said means comprising contacts exerting a spring pressure urging both of the jaws into clamping position with the device.
  • fuse including a ferrule at its end movable longitudinally into position between said holding jaws, said holding aws being thereafter movable laterally into position embracing the ferrule and making contact therewith, including locking means for preventing longitudinal withdrawal of the fuse, from between the holding aws.
  • a fuse including a ferrule at its end, a fuse holder including a pair of holding members movable laterally of the ferrule into embracing relationship thereto, and cooperating means between the fuse hold er and the fuse for locking the holding mem bers in their fuse holding position and lock ing the fuse against outward withdrawal when the holding members are in that position.

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Description

NOV. 8, 1932. BLOMQUIST 1,887,281
FUSE
Original Filed March 25, 1929 2 Sheets-Sheet 1 5 52%6/25'07' nsifilomfaisa Nav. 8, 1932 E. BLOMQUEST FUSE Original Filed March 25, 1929 2 Sheets-Sheet nQHKM NQNM:
fave/M Patented Nov. 8, 1932 UNETED STATES PATENT OFFICE ERNST BLOMQUIST, F LOMBARD, ILLINOIS FUSE Original application filed March 25, 1929, Serial No. 349,877. Divided and this application filed May 12, 1930. Serial No. 451,722.
This application is a division of my pending the fuse while inserting the same into or ing application, Serial No. 349,877, filed removing it from the stationary part. The March 25, 1929, and relates in general to fuse removable or manipulating part comprises a holders. short insulating member one end of which In recent years, with the coming lnto use is provided with a handle which is adapted to 5 5 of higher and higher distribution and tranS- be gripped by the hand and the other end of mission voltages the matter of obtaining a which is provided with means for gripping compact and economical distribution center the lower ferrule of the fuse. This means or substation has become amatter of great preferably comprises a chuck having two 0 importance. In my parent application of Jaws which may be opened. to receive the fuse which this is a division I show a substation ferrule and thereafter clamped into tight enwhich comprises a number of separate relagagement therewith. The inner sides of the tively small sheet metal switch houses each jaw of the chuck are preferably made to concontaining toe necessary switching equlpform with the contour of the ferrule so as 15 ment arranged in a very compact manner. to obtain a firm grip thereon and to make In certain circuits fuses are used and where good electrical contact therewith. The chuck a compact arrangement is desired the locais made of metal of high conductivity and tion and mounting of the fuses must receive constitutes the terminal for establishing a cirspecial attention. The fuse used may be a uit through the ferrule to the fuse.
2o standare type which comprises a fusible ele- The stationary part of the fuse holder comment within a glass tube filled with carbon prises an insulating member of a generally tetrachloride or other insulating liquid of tubular shape, the spring contact clips previhigh are extinguishing properties, the tube ously mentioned being located within the being provided at itsoppositeendswithmetalmember and at the opposite ends thereof.
25 lic ferrules that comprise the fuse terminals. The fuse is first mounted in the chuck and is lVhen such a fuse blows under very heavy inserted through the tube of insulating mashort circuiting conditions it frequently terial and into engagement with the contact shatters the glass tube and if it is in the imclips by manually gripping the handle of mediate vicinity of grounded or live parts the removable member and plunging the fuse :10 there is adanger of establishing an arc to into the stationary member. WVhen the fuse those parts. This is, of course, an occurrence is fully inserted in place the upper contact which must be prevented under all condiclip engages the upper ferrule and the lower tions. To prevent this occurrence it has contact clip engages the chuck, thus connectbeen customary, in the past, to allow a coning the fuse in circuit.
35 siderable spacing between the fuse and other In such an arrangement it is apparent that 9 grounded or live parts. Such a solution is the movable chuck holding insulator is the objectionable where a compact arrangement only thing that separates the hand of the opis desired. erator from the terminal clips during the I propose to provide a fuse holder wherein operation of inserting or removing the fuse.
the fuse including the ferrules and the glass Should the terminal clips happen to be alive tube containing the insulating liquid and the during these operations and should the chuck fusible element may be inserted. The fuse holding insulator happen to be defective the holder is made of insulating material and is operator would be placed in great danger unprovided with spring contact clips at its opless some protective means were provided.
posits ends for receiving and making contact As pointed out in my parent application and with the opposite ferrules on the fuse. I in the particular arrangement there shown, I
prefer to make the fuse holder in two parts, provide an interlocking arrangement for preone of which is stationary, being rigidly venting the insertion or removal of the fuse mounted, and the other of which is removwhile the terminal clips are connected in cirable, being the part provided for manipulatcuit. As an additional safeguard, and one which is of general application to all systems whether or not they are provided with an interlocking arrangement, I provide grounding means for grounding the portion of the fuse holder adjacent the handle when the same is at or near the position that it occupies when the fuse is in place. This comprises a metallic plate interposed between the handle and the chuck holding insulator and a number of grounding spring contacts which engage the plate as the same approaches the position that it occupies when the fuse is in place.
Fuses of the type here shown are provided with a vent cap which is adapted to be blown out when the fuse is blown by a heavy short circuit. It is necessary that the fuse be mounted with this vent cap directed upwardly. To prevent the insertion of the fuse with its wrong end extending upwardly I arrange the chuck so that it can not fully close when the wrong one of the two ferrules is inserted therein. As a further precaution against the improper insertion of the fuse I arrange the contact clips on the stationary mounted portion of the fuse holder so that the fuse can not be inserted in place unless the chuck is fully closed on its ferrule.
In order to acquaint those skilled in the art with the manner of constructing and operating a device in accordance with my invention, I shall describe, in connection with the accompanying drawings, a preferred embodiment thereof.
In the drawings Figure 1 is a partial longitudinal section of my improved fuse holder;
Figure 2 is a partial longitudinal section of the upper contact clip of the fuse holder;
Figure 3 is a partial longitudinalsection of the lower contact clip;
Figure 4: is a partial longitudinal section of the chuck forming a part of the fuse holder;
Figure 5 is a sectional view taken along the line 55 of Figure 4 and looking in the direction of the arrows;
Figure 6 is a sectional View taken along the line 66 of Figure 4; and looking in the direction of the arrows;
Figure 7 is a side view of a box within which the fuse holder is mounted, said view being taken with the side cover of the box re moved; and
Figure 8 is a front View of the fuse and switch box shown in Figure 7.
Reference may now be had more particularly to Figure 1 of the drawings showing my novel form of fuse holder. Although the principles embodied in my fuse holder are capable of general application, the specific embodiment shown illustrates a fuse holder for use in connection with what is now known as a Schweitzer and Conrad type of fuse, such as is disclosed for example in the patent of glass or the like having terminal ferrules 11 and 12 at its opposite ends, the fuse element being located within the body of the fuse and surrounded by a body of insulating liquid of high are extinguishing properties for quenching any are that may form upon the blowing of the fuse. Reference may be had to the above referred to patent for a more complete description of this type of fuse. It is, however, to be understood that my invention is not limited for use in connection with a fuse of a particular construction such as is shown in this application but may be used with other forms of fuses if desired.
The fuse holder is indicated in general by the reference numeral 15 and comprises an insulator member 16 of a generally tubular form which is secured by means of a bracket 17 to the wall of a cabinet such as is shown '11 Figures 7 and 8. It is however to be understood that this fuse holder may be mounted in a manner other than that here shown and need not necessarily be located in a cabinet such as is shown in Figures 7 and 8. An internally threaded copper tube 19 to which an upper terminal member 20 is soldered or otherwise suitably secured is itself suitably cemented in the top of the insulator 16. A tube 21 of copper or other suitable metal for high conductivity is threaded into the tube 19. The tube 21 is shown more particularly in Figure 2 and is provided with external threads 22 that thread into the internally threaded member 19. Bronze spring contact clips 2A are soldered at 25 on the outside of the tube 21 and are bent up within the tube, the ends 26 of these springs being free. The spring contact clips 24 are inwardly bowed as may be seen from Figures 1 and 2 and they engage the upper ferrule 11 of the fuse and establish an electric circuit between the terminal 20 and the fuse through the members 21 and 19. The member 21 is provided with two screw driver slots indicated at 27 to facilitate the insertion and removal of that member from the tube 19.
The fuse holding or gripping portion of the fuse mounting comprises an insulator 30 into the iottom of which is cemented or otherwise suitably secured an internally threaded member 31 forreceiving the handle. The handle comprises a gripping member 32 of wood or other suitable insulating material and having a steel shank 33 secured therein. The upper portion of the steel shank is screw threaded and it threads into an opening in the member 31. A plate 35 of brass or other suitable conducting metal is interposed between the top of the handle 32 and the bottom of the member 31, a lock washer 36 being located between the brass disc or plate 35 and the member 31 for holding the handle and the disc 35 rigidly QR. I
in place with respect to the member 31. A mounting in .nber 40 Similar to the member 31 is cemented within the top of the insulator 30 and is internally threaded to receive the end of a chuck such as is shown more fully in Figure 4.
The chuck comprises a threaded shank or stem member 45 slotted at the top to receive a bar 46, said bar being pivoted to the shank 45 by means of a pivot pin 47 so as to allow a limited amount of swinging movement of the bar or lever 46. Two chuck aws 48 and 49 are pivoted to the lever rod 46 by means of pins 50 and 51 respectively.
The two chuck jaws 48 and 49 are slotted at their lower ends as indicated at 53 to permit a swinging movement of the aws about the pivot pins 50 and 51 respectively, the lever 46 swinging in those slots during this movement of the jaws. The two chuck jaws are adapted to receive the lower fuse ferrule 12 between them and they are provided on their inner sides with a shoulder at their lower end to limit the downward movement of the ferrule and with a shoulder 61 at their upper end to limit the upward movement of the ferrule. The inner surface of the chuck jaws between these two shoulders is of a generally cylindrical shape and the lower fuse ferrule 12 fits snugly within the jaws between the shoulders whereby the aws of the chuck establish good electrical contact with the ferrules. The jaws of the chuck are made of metal having a high conductivity whereby the chuck jaws may act as a terminal for the fuse. There is provided a chuck tightening and loosening ring member 65 which has a cone-shaped upper portion 66 and which is freely slidable upon the shank or stem 45. WVhen the stem 45 is threaded into the threaded hole in the mounting member 40 in the top of the insulator 30,
the ring member 65 lies between the top of the mounting member 40 and the bottom of 'i the chuck jaws 48 and 49.
The shank or stem 45 is normally threaded into the mounting member 40. As the same is threaded further and further into the mounting stem the bottom edge of the chuck i jaws 48 and 49 are brought closer and closer to the ring 65. Prior to their engagement with the ring these jaws are free to swing about their pivot pins 50 and 51 extending through the lever 46 and likewise the lever 46 is free to swing about its pin 47. This means that the jaws are free to open at their upper ends, that is at their ends above the pivoted lever 46. As the stem 45 is further threaded into the mounting member 40 the cone portion 66 enters into the space between the two chuck jaws and limits the extent to which the jaw 49 may swing in a clockwise direction and the extent to which the jaw 48 may swing in a counter-clockwise direc tion. This means that it limits the extent of opening movement of the portion of the jaws above the lever 46. In order to mount the fuse 10 within the chuck jaws the stem 45 is unthreaded a certain amount from the mounting member 40 so as to permit an opening of the jaws sufficient for the insertion of the lower fuse ferrule 12 between the jaws. The lower fuse ferrule 12 is then inserted between the jaws until the bottom of the fuse ferrule rests upon the shoulder 60. The stem 45 is then threaded further into the mounting member 40. WVhen this is done the conical shaped portion 66 of the ring 65 is forced upward between the lower portion of the chuck jaws thereby forcing the lower portions of the jaws to swing outwardly about the pivot pins 50 and 51 and thus to force the upper portion of the jaws to swing inwardly, thereby firmly gripping the fuse ferrule that is between these jaws. The pivoted bar or lever 46 equalizes the extent of movement of the two chuck jaws. The spac ing between the shoulders 60 and 61 is made equal to the length of the lower fuse ferrule so that the chuck maintains a firm grip upon the fuse. The handle 32 of the fuse hol-r is then gripped by hand and the fuse and the bottom portion of the fuse holder, namely the insulator 30, are inserted through a grounded shield 68, of which more will be said as the description proceeds.
The fuses passes through the insulator 16 until the upper ferrule 11. is engaged by the spring contact clips 24. At this time the outer surfaces of the chuck jaws engage a lower terminal clip 70 which is of a construction similar to the terminal 21 and which is shown more fully in Figure 3, which is electrically connected to a line terminal 71. The fuse thus establishes a circuit between the terminals 20 and 71 of the fuse holder.
The lower fuse terminal clip '70 which secured within the insulator 15 comprises a ring 75 of copper or the like, which is internally threaded adjacent its upper portion which is cemented or otherwise suitably cured within an enlarged bore in the lower portion of the insulator 15. A line terminal 71 is soldered or otherwise suitably electrically secured to the ring member 75. The ring 7 5 is adapted to receive a ring 76 of a construction such as is shown more particu larly in Figure 3. The ring 76 comprises a tube of copper or the like which is threaded at its upper portion as indicated at 77 and is provided with a number of spring contact clips 78 that extend on the inside thereof for engaging the outer surface of the jaws of the chuck. The spring clips 7 8 on the inner side of the tube member 76 are bent back and under the tube, the ends 79 of these springs being secured in intimate contact with the wall of the tube. I have shown a preferred manner of obtaining this intimate contact. This comprises a ring'or collar 80 that is pressed onto the bottom of the member 76 on the outside ofthe spring.
This collar forms a rather tight fit with the spring and is held in place by a number of screws 81 that extend through the collar and are threaded into suitably tapped holes in the member 76. The bottom of the member 76 may be provided with. a number of slots through which the spring contact clips 7 8 extend sothat the bottoms of these contact clips are flush with the bottom of the member 7 6 and the ring or collar 80 is provided with an inwardly extending shoulder portion that fits over the bottom of the member 76. As may be seen from Figures 1 and 3 the spring clips are bowed inwardly toward the center of the ring member 7 6 and are free at their upper ends, these ends bearing against the cylindrical inner surface of the ring mem ber 76. By this arrangement the contact clip springs 78 are enabled to maintain firm spring contact against the outer cylindrical wall surfaces of the chuck members 4:8 and 49.
In fuses of the kind herein shown the upper ferrule is provided with an explosion cap which is adapted to be blown outwardly )y the explosion within the fuse chamber when the fuse therein interrupts a current of magnitude. For this reason it is therefore essential that the fuse be mounted with its ferrule 11 in the upper position. The forrule 11 is slightly longer than the ferrule 12 and it will therefore not fit into the space between the two shoulders and 61 of the chuck. If an attempt is made to insert the ferrule 11 into the jaws of the chuck instead of inserting the ferrule 12 therein, the end of this first mentioned ferrule will not fit into the chuck and the jaws of the chuck will flare outwardly by such an amount that the chuck cannot be inserted through the ring 80, Therefore, if the operator has not previously i noted his error he is thereby apprised of the fact that the long end of the fuse has been inserted into the chuck and he must correct this before the fuse can be embedded in place within the fuse holder.
A cap 85 preferably of asbestos or other suitable insulating material capable of with standing high temperatures is secured to the insulator 1.6 by means of number-of strips 86 and a strap clamp 87 which is clamped around the insulator 16, the ends of the strap 87 being bolted or otherwise secured together 88. The cap 85 is supported in spaced relationship from the insulator 16 by the str'ps 86, a plurality of these strips being prov W... The asbestos cap 8? is provided in order to stop an arc that may be formed by a Violent explosion of the fuse and which might otherwise tend to go to ground t the top of the cabinet within which the fuse holder is mounted.
As previously stated, the fuse and with it the insulator portion 80 and the handle 32 is passed through a grounded shield 68 to insert the same in position within the insu later 16. This shield is mounted within the fuse cabinet wherein the insulator 16 is mounted, the shield being spaced from that insulator as shown in the drawings. The shield is provided with a number of spring wire contact clips 90 secured on the inside thereof and spaced from one another by small amounts. Each of the spring contact wires 90 is provided with a shoulder 91 adjacent its upper end. When the fuse is inserted through the grounded shield, t.1e brass disc 35 passes beyond the upper shoulder 91 of the springs, forcing these springs outwardly during its passing movement. As the disc is inserted beyond the shoulders 91 these shoulders spring back to the position as shown in the drawings and, upon release of the handle 32 these springs at their shoulders 91 support the insulator 30 and the parts secured thereto thereby holding them in the position as shown in Figure 1. To remove the fuse it is merely necessary to pull downwardly upon the handle 32. When this is done the springs 90 yield slightly thereby permitting the withdrawal of the insulator 30, and with it the parts mounted thereon, through the grounded shield 68.
It may be seen that the fuse holder shown is not only simple and turdy in construction but is exceedingly safe to manipulate, for when the operator grasps the handle 32 to remove the fuse, or to insert the same into place, the grounded shield 68 and the grounded disc 35 render it impossible for the operator to come into contact with electrically alive parts. Should the insulator 30 become defective the operator would still be protected since the parts adjacent the handle 32 are grounded.
Reference may now be had to Figures 7 and 8 showing a cabinet within which a fuse holder such as is shown in Figure 1 is mountcd. This is shownfor illustrative purposes and it is to be understood that the fuse holder may be mounted in specifically different l'cinds of cabinets. "he cabinet comprises a substantially rectangular metallic box 100 which may be of any approved construction. The cabinet shown in Figure 7 is adapted for use on three-phase systems, although it may be used on other systems, and has mounted therein a triple pole double throw switch 105, One pole being provided for each phase.
Conduits 101, 102 and 108 QX ZGDCl into the cabinet, the various conductors through which the various circuits pass beingext'ended into the cabinet through these conduits. The conductors from the conduit 103 extend to one set of terminals, indicated at 106, and the conductors from the conduit 102 extend to the opposite terminals 107 of the three pole switch. The blades 108 of the switch are pivoted at 109 and are adapted to selectively engage either the terminals 106 or the terminals 107. There are three fuse holders such as the fuse holder 15 of Figure 1 mounted within the cabinet, one fuse being provided for each phase. The fur are mounted in spaced relationship, one of these fuses being seen in Figure 7, the other two being directly behind the one there soon. In this construction the fuse holder i shown as mounted in an inclined position and is adapted to have the fuse inserted therein through the side wall 115 of the cabinet. For this purpose the side wall is provided with a door 116 which is hinged to the wall 115 by means of hinges 117 and 118. A pipe member 120 is pivoted between the pivots 121 and 122 and is provided with a portion 123 which overlies the door 116 and when in that position it prevents opening of the door and thereby prevents the insertion or removal of a fuse from the fuse holder. A rod 125 is provided for manipulating the pipe 120 to swing the same into or out of position in front of the door 116. This rod 125 is connected to suitable interlocking means (not shown) for preventing the opening of the door 116 while the circuit to the opposite terminals of the fuse is closed. The shields 68 for the three fuse holders are shown in dotted lines in Figure 8, these shields being cut off at an angle in order to permit mounting of the fuse holder in an inclined position. A handle 130 is provided for operating the triple pole double throw switch 105. This handle is connected to rotate the shaft 131 which rotates a set of crank arms 132 which act through a set of insulating rods 133 to actuate the blades 108 of the switch. The rods 133 may be made of bakelite or any other suitable insulating material. The upper terminals 20 of the fuse holder are connected to the central clips of the respective poles of the three pole switch 105 and the lower terminals 71 of the fuse holder are connected to conductors which 8X- tend from the switching cabinet through the conduit 101.
Because of the provision of the fuse holder having the insulating tube 16 it is possible to mount the fuse a good deal closer to the other grounded or live parts within the switching cabinet than would be safe in the absence of the fuse holder. Upon the occurrence of even the most violent short circuit there is no danger whatsoever of an are being produced by the blowing of the fuse and spreading to the other parts within the switching cabinet.
In compliance with the requirements of the patent statutes I have herein shown and described a preferred form of my invention. It is however to be understood that the invention is capable of various modifications and that the form herein shown is merely illustrative of the invention. hat I consider new and desire to secure by Letters Patent is 1. A fuse holder comprising a grounded metallic tubular member, grounded spring clips within the member, a fuse holding insulator insertable through said tubular member, a fuse receiving chuck mounted at one end of the insulator, a handle mounted at the other end thereof and a metallic plate interposed between the handle and the insulator, said plate resting upon and being removably supported by the spring clips when the fuse holding insulator is inserted through the tubular member.
2. A fuse holder comprising a grounded metallic tubular member, grounded spring clips within the member, a fuse holding insu lator insertable through said tubular member, a fuse receiving chuck mounted at one end of the insulator, a handle mounted at the other end thereof, and a metallic plate interposed between the handle and the insulator, said plate resting upon and being removably supported by the spring clips when the fuse holding insulator is inserted through the tubular member, said grounded tubular member being of a diameter suflicient to permit the free entry of a hand therein to grip the handle.
3. A fuse holder comprising a block of insulation, a fuse receiving chuck mounted on one end of the block, a handle mounted on the other end of the block, and a grounding plate interposed between the handle and the insulation.
4:. A fuse holder comprising an insulator, a fuse receiving chuck mounted on one side of the insulator, a handle mounted on the other side of the insulator, a metallic plate interposed between the insulator and the handle, and a short grounded metallic tubular member surrounding the fuse holder at the handle and being of a diameter to permit the free entry of a hand therein to grip the handie and withdraw the fuse holder, said tubular member being in electrical contact with said plate.
5. A fuse holder comprising an insulator, a fuse receiving chuck mounted on one side of the insulator, a handle mounted on the other side of the insulator, a metallic plate interposed between the insulator and the ban dle, and a short grounded metallic tubular member surrounding the fuse holder at the handle and being of a diameter to permit the free entry of a hand therein to grip the handle and withdraw the fuse holder, and spring means for maintaining electrical contact between the tubular member and said plate.
6. In combination, current flow interrupting means having a terminal portion at one end, an insulator, means for gripping one end of the insulator, and a chuck at the other end of the insulator for gripping the terminal portion of the current flow interrupting means, the chuck constituting the means for cal establishing a circuit through the interrupting means, and including means for tighten ing the chuck against the terminal, said last means being controlled by rotation of the insulator with respect to the chuck.
7. Switching means comprising a tube of insulation, contact clip members on the inside of the tube, means for mounting the tube in a generally vertical position, current flow interrupting means having terminal members at its opposite ends, conducting means for gripping one of the terminalsof said first means and thus supporting said first means, said current flow interrupting means being within the tube of insulation with its other terminal member in. engagement with one of the contact clips and with said conductive gripping means in engagement with the other clip, thus establishing a circuit between said clips, the upper end of the current flow interrupting means being expellable, and an insulating cap mounted on the tube and spaced above the upper end thereof.
8. Switching means comprising a tube of insulation, means mounting the same in a generally vertically extending position, a pair of contact clip members mounted on the inside of the tube, a fuse comprising an outer tube having ferrules at the opposite ends thereof and a fusible element therein connected between the ferrules, means for gripping one of the ferrules of the fuse, said fuse tube being of an outside diameter appreciably smaller than the inside diameter of the first tube and being within the first tube, said last named means being in engagement with one of the contact clips and the opposite ferrule being in engagement with the opposite contact clip, the upper ferrule including an expellable cap, and said outer tube of insulation being open at the tip to permit expulsion of the products of a circuit interruption.
9. Switching means comprising a tube of insulation, a pair of contact clip members mounted on the inside of the tube, a fuse comprising an outer tube having ferrules at the opposite ends thereof and a fusible ele ment therein connected between the ferrules, means for gripping one of the ferrules of the fuse, said fuse tube being of an outside diameter appreciably smaller than the inside diameter of the first tube and being within the first tube, said last named means being in engagement with one of the contact clips and the opposite ferrule being in engagement With-the opposite contact clip, said means for gripping the ferrule of the fuse having means associated therewith for locking itself to the ferrule for inserting and removing the fuse from the first mentioned tube.
10. A fuse holder comprising a pair of arms pivoted intermediate their ends and adapted to receiveafuse between them at one end, means adjacent the other ends of the arms for spreading those ends apart thereby forcing the opposite ends towards one another into gripping relation to the fuse, means for holding the fuse holder, said means including a handle and insulation between the handle and the pair of arms, and an insulating tube into which the fuse is adapted to be inserted by the holder, said tube including contact means which engage the pivoted arms and establish a circuit there through.
11. In combination, a chuck including a pair of gripping jaws adapted to grip an electrical device, screw threaded means for tightening the jaws to clamp the device, means for holding the chuck, said means comprising a handle insulated from the chuck, and grounding means interposed between the handle and the chuck and also insulated from the chuck.
12. In combination, a chuck including a pair of gripping jaws adapted to grip an electrical device, screw threaded means for tightening the jaws to clamp the device, means for holding the chuck, said means comprising a handle insulated from the chuck, and means for extending a circuit to the chuck and through it to an electrical device held therein, said means comprising contacts exerting a spring pressure urging both of the jaws into clamping position with the device.
13. In combination with a fuse holder having a pair of fuse holding jaws, fuse including a ferrule at its end movable longitudinally into position between said holding jaws, said holding aws being thereafter movable laterally into position embracing the ferrule and making contact therewith, including locking means for preventing longitudinal withdrawal of the fuse, from between the holding aws.
14. In combination, a fuse including a ferrule at its end, a fuse holder including a pair of holding members movable laterally of the ferrule into embracing relationship thereto, and cooperating means between the fuse hold er and the fuse for locking the holding mem bers in their fuse holding position and lock ing the fuse against outward withdrawal when the holding members are in that position.
In witness whereof, I hereunto subsc *ibe my name this 8th day of May, 1930.
ERNST BLOMQUIST.
US451722A 1929-03-25 1930-05-12 Fuse Expired - Lifetime US1887281A (en)

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US349877A US1930156A (en) 1929-03-25 1929-03-25 Substation
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2746024A (en) * 1951-04-28 1956-05-15 Joy Mfg Co Sockets for flat blade pins

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2746024A (en) * 1951-04-28 1956-05-15 Joy Mfg Co Sockets for flat blade pins

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