US2131292A - Fuse ejector - Google Patents

Description

Sept. 27, 1938. T. E. MCDOWELL ET AL 2,131,292

FUSE EJECTOR Filed April 19, 1937 fig Patented Sept. 27, 1938 UNITED STATES PATENT ()FFICE FUSE EJECTOR Jersey Application April 19, 1937, Serial No. 137,669

1 Claim.

The present invention relates to a fuse ejector construction for fused plug.

The invention relates more particularly to expulsion fuse construction and is concerned with devices utilizing removable fuses of the cartridge type wherein the fuses may be readily removed and renewed without the use of tools to separate the parts maintaining the fuses in electrically connected relationship.

The present invention will be described in connection with a separable connector of the type disclosed in Thomas E. McDowell Patent No. 2,015,953, dated October 1, 1935, although it is to be understood that the present invention is capable of use in other embodiments.

The present invention is useful in external electrical conductors, such for example, conductors utilized for operating electrically driven portable tools and the like, connections to the electrical equipment of railway trains while at rest to supply power for the operation of air-conditioning apparatus, charging the train batteries, as well as other purposes.

Electrical connectors for use in the relations mentioned must be small and constructed to afford no projections which catch as the conductors in which such connectors are applied, are dragged from place to place in service, at the same time such connectors must be small as possible and yet capable of carrying proper current, and at the same time constructed to withstand the severe and rough treatment received in normal use.

An object of the present invention is to provide a fused plug in which the fuse means may be readily removed and replaced in minimum time and without the use of tools.

Another object of the present invention is to provide a fused plug in which the insulating means carrying the conductor elements and fuse comprises two separable parts each recessed to provide, when together, pockets for the fuses, and in one of which parts the fuses are frictionally gripped for preventing accidental displacement of the fuses as the members are connected or separated, while the other of the members is provided with means for automatically displacing or ejecting the fuses from the recesses in this member and to move the said one member away from the other member when the holding means are released, thereby making it unnecessary to use a tool to separate the members or to withdraw the fuses from said other member of the insulating means of the plug.

The above other and further objects of the present invention will be apparent from the following description and accompanying drawing.

The accompanying drawing illustrates a fused plug constructed in accordance with the principles of the present invention, and the views thereof are as follows:

Figure 1 is a view, partially in elevation and partially in central vertical section along line I l of Figure 2, through a fused plug which constitutes one part of a separable electrical connector.

Figure 2 is an end view of the plug of Figure 1, looking the right-hand end of the same.

Figure 3 is end elevational view of the inner or rear end of the insulating body.

Figure 4 is a view, partially in elevation and partially in central vertical section, showing one of the insulating members moved away from the other by the action of one form of fuse expulsion means of the present invention, when the means for holding the two members together are released.

Figure 5 is an elevational view of one of the insulating members carrying pin contacts, and showing the same with fuses carried thereby, and the screws, for securing the two members together, withdrawn.

Figure 6 is an isometric View of one of the fuse contact members utilized in the recesses or pockets of the insulating members of the plug.

Figure '7 is a fragmental sectional view of a portion of an insulating body showing a portion of a cartridge fuse and another form of expulsion means for ejecting the fuse.

The drawing Will now be explained.

The plug shown in Figure 1 includes an insulating body comprising two members I and 2 which are adapted to be connected together for establishing electrical circuit relationship,through enclosed removable fuses.

Members I and 2 are cylindrical, and are connected together by means of screws or bolts 3, 4, and 5, carried by the one member 2. The one member 2 is provided with axially extending apertures E for the bolts, which apertures are equally spaced, circumferentially, within the cylindrical surface of the member. The member is recessed at l to receive the heads of the screws when the same are threaded into the other member I. In order to receive the screws in threaded engagement the other member I is provided with threaded bushings 8, as may be readily observed in Figure l.

The member I is provided with conductors 9 passing from the inner end of the member, which is the left-hand end as viewed in Figure 1, and terminating within recesses or pockets l formed in the member. Bottomed in the recesses or pockets l6 are contact-making cups II which are electrically connected to the conductors 9. The outer ends of the conductors 9 are provided with clips 52 and binding screws l3 for connecting conductor wires to the several conductors 9. In the invention as herein illustrated, there are three of such conductors 9, constituting three poles of the plug, while the fourth pole constitutes an elongated conductor element M which passes through the member from end to end, and is prevented from rotation in said member by means of a polygonally shaped integral portion l5 which engages a correspondingly shaped recess in the front face of the member. The rear end of this conductor M is provided with a clip l6 and a binding screw il Thus the illustrated plug is arranged as a four-pole plug. 4

The three poles of the plug, which are electrically connected with the several conductors 9, are protected by removable fuses A, applied as illustrated.

The insulating member 2 is provided with recesses or pockets 53, with the same number and axial arrangement as the pockets or recesses H! in the member l. Within a pocket 18 is a cupshaped contact member l9 to which is connected a pin connector 20, the connector 20 being soldered or otherwise secured to the cup IS, the cup and pin connection 2i! being applied in the member 2 by inserting the same through the open end of a recess it, the outer end of the member 2 being suitably apertured as at 2! for the pin connectors 29. The cup-shaped contact member is, one of which is illustrated in Figure 6, is so constructed as to frictionally grip and hold one end of an inserted fuse A. The fuses A of known form, are provided with metallic end members 22 and 23 for making the electrical connection with the cups l9 and ll respectively.

Fused plugs, of the general character herein described, have been in use. However, it has been demonstrated by experience that the fused plugs of the present type of manufacture, when it is necessary to renew the blown fuses, offer resistance to ready fuse renewal.

Where such fuses have been inserted in fused plugs between. cups in the inner member I, and other cups in the outer member 2, oftentimes the cups engage the fuses with such frictional force as to prevent removal of the outer member 2 by a pulling pressure applied by hand to one of the pin contacts All. In such event the workman, has employed pliers to pull the member 2, which is disadvantageous, as the pliers damage the engaged pin contact 26. Even when the workman is successful in pulling out the outer insulating member 2, by means of pliers or other tool applied to one of the pin contacts 20, some times the fuses have remained frictionally held in the inner member I. When this occurs a workman attempts by means of pliers or other tool to pull out the fuses. To accomplish fuse renewal, in the manner just described, requires much more time than is warranted and necessitating shutting down a connected electrical tool or machine beyond a desired amount, and at the same time damaging some of the vital parts of the connector.

The present invention overcomes the above recited objections by providing expulsion means within the pockets or recesses ll] of the inner member I, to automatically free or expel the fuses, as soon as the outer member 2 is separated from the inner member I.

The means illustrated in Figures 1 and 4 for accomplishing this purpose, comprises a coiled spring 24 inserted in a cup or stationary fuse clip I I of the member I. There are, of course, as many of the springs 24 employed as there are cups II in the member I. Preferably the springs are of substantially conical shape in elevation, with their bases soldered or otherwise secured to the bases of the cups to prevent loss of the springs, while the insulating member 2 is separated from the insulating member I. It is to be understood, of course, that other types of springs or equivalent resilient means may be utilized in lieu of the coiled springs illustrated. The springs 24 are placed under compression, when the member 2 is connected to the member I, to connect the fuses A in circuit connecting relationship between the conductors 9 and the pin contacts 20 and remain under compression as long as these members are connected. Whenever a fuse blows, all that the workman or operator has to do is to release the screws 3, 3, and 5 from threaded engagement with the insulating member whereupon the springs 24 become effective to shift or eject the fuses, from the position shown in Figure 1, to the position shown in Figure 4, moving with the fuses the outer insulating member 2, thus loosening it, so that the operator or workman may remove the member 2 by grasping one of the pins 20 with his fingers and separating the member 2 so that the blown fuse or fuses may be replaced. When the blown fuses have been replaced the member 2 with the fuses therein is applied to the member l, and the two members fastened together in operative relation, by the screws 3, 4, and 5, as shown in Fig ure 1.

The fused plug herein illustrated includes a casing or housing 25 which receives a portion of the inner or rear end of the member I, when the parts are assembled. The housing 25 has an integral neck 26, which is hollow and through which the conductor wires are passed for connection to the conductors 9 and M. A strain-relief fitting, designated generally at 21, is provided for purpose well understood.

Surrounding the housing 25 is a sleeve 28 which extends beyond the extremities of the pin contacts 20 and the contact 14. The sleeve is mounted on the housing 25 for limited rotative movement for use in disconnecting the plug member from a mating receptacle, such as that appearing in Thomas E. McDowell Patent 2,015,953. The sleeve 28 is provided with elongated, circumferentially extending slots 29 and 30, through which pass screws 3! and 32 respectively for preventing separation of the sleeve from the housing. One or both of the screws 3! and 32, or a third one, if necessary, may extend into and engage suitable recesses in the inner insulating member I for maintaining the insulating members I and 2 fixed in the housing 25.

While the invention has been described herein in connection with a plug member of a separable connector such as that shown in Thomas E. McDowell Patent 2,015,953, nevertheless the invention may be incorporated in other forms of electrical connectors. The invention, however, finds ready use in connection with the form of plug described, for the reason that the plug is of minimum diameter to reduce its weight and size, for the current carried by the conductors. Thus the limitation of size is an item to be regarded in connection with the present invention. It may be readily observed that the space offered by the open end of the sleeve 28 is limited so that it would be far from easy to insert a pair of pliers to grasp one of the pin contacts to separate the insulating member 2 from the insulating member I, were the fuses gripped by the cups I I of the member I, thus offering material resistance to separation of the members. By means of the present invention, as soon as the bolts or screws 3, 4, and are released from threaded engagement with the member I, the springs 24 immediately eject the fuses A from the cups II to such an extent, as to separate the member 2 from the member I, whereupon it is easy to withdraw the member 2 from within the sleeve 28 and replace the blown fuses with others.

The provision of the contact member l4 which serves as a safety ground circuit and can not be fused because of code requirements also serves to guide the two parts, when pushed together, to maintain the polarity of the pin contacts after the member 2 has been separated from the member I, and the former is returnedto again efiect electrical connection through the plug.

Figure 3 illustrates the rear end of the member I of the insulating body where it may be observed that the heads of the several conductors are separated one from another by means of partitions 33, formed as integral parts of the member I, so that there is no likelihood of short circuits occurring between any of the contacts of the plug members.

Referring to Figure 6, it will be observed that the cups, of which this is an example, are formed with bases 34 and spaced side walls 35, 36 which are curvilinear in plan, and which are connected to the bases 34 by necks 31 of reduced circumferential extent. The side portions 35 and 36 are formed with legs 38 which extend toward the bases 34, and which may be slightly bent, prior to application of the cups to the pockets or recesses, to frictionally hold the cups in place in the pockets or recesses and at the same time engage the metallic ends 22 of the fuses with sufiicient frictional clamping engagement to normally retain the fuses in the member A, against accidental displacement.

The fuse ejector of the present invention may be used with any sort of an insulating body, with or without an enclosing sleeve, such as the sleeve 28, as the two members I and 2, comprising the insulating body, may be constructed as herein described and the springs 24, or equivalent means, employed to eject or free similar ends of the fuses, when the members are separated for fuse replacement.

In order to prevent accidental loss of the screws 3, 4, and 5, from the member 2, by falling out, due to gravity, when the latter is removed from engagement with the member, the outer ends of the aperture 6 may be threaded; and the apertures inwardly of the threads may be slightly enlarged, thus permitting lengthwise movement of the screws within the aperture and preventing removal of the screws unless unscrewed through the threaded ends 40 of the apertures.

The principle involved in the operation of the ejector shown in Figures 1 and 4, covers a stationary fuse clip, such as a cup I I, and an independent spring, such as a spring 24, for ejecting a fuse.

Another principle of operation is involved in the arrangement shown in Figure '7, i. e., utilizing a movable clip secured to the free end of a spring,

the clip constituting the contact member following the fuse out of its pocket or cavity in the insulating member I.

Referring to Figure 7, a spring 4I is secured to one end, by soldering or otherwise, to the inner end of a conductor terminal 42, that is, the end of the terminal making contact within a pocket or cavity ID. Secured to the free end of the spring 4 I, as by soldering or the like, is a shallow clip or cup 43, which receives one end of a cartridge fuse A in circuit making relation.

When this type of ejector is used, the springs M are compressed when the members I and 2 are connected together by the screws, and remain under compression so long as members I and 2 are connected. When a fuse has to be removed, the springs free or expel the fuses A from the pockets or cavities I0 and at the same time displacing the outer insulating member 2 to the position shown in Figure 4, so that the member 2 and its carried fuses may be readily removed from the casing 28. During such expulsion of the fuses A by springs operating under the principle described, the clips or cups 43-the contact membersfollow the fuses to the limit of spring travel.

The showing of Figure '7 is not one of limitation, but is exemplary of another form of expulsion means. Spring or other shapes and kind may be substituted for the one specifically illustrated, so long as the principle of operation is retained, viz., causing the clip, or any equivalent contact member to follow the fuse, when expelled by the spring, to the limit of spring travel.

The invention has been described herein more or less precisely as to details, yet it is to be understood that the invention is not to be limited thereby, as changes may be made in the arrangement and proportion of parts, and equivalents may be substituted, without departing from the spirit and scope of the invention.

The invention is claimed as follows:

An electrical connector of the class described comprising a shell having an open end to receive a mating connector; an insulating pin carrying body within said shell enterable through said open end and bottomed within said shell with its outermost face spaced inwardly of said open end; said body comprising two members connected together with adjacent end faces in contact and at rightangles to the casing axis; screw means available through said open end for securing said two mem bers together within said casing; male contact pins projecting outwardly of the outermost face of said body with the pin extremities terminating inwardly of the plane of said open end; said body members being counterbored through their adjacent faces to provide cartridge fuse pockets; contact cups bottomed in said pockets and connected in circuit relation; and repellant springs in the cups of the inner body member arranged to connect the fuses in circuit relation and possessing sufficient strength to automatically push the fuses endwise out of the said cups and therewith move the outer body member axially of the shell when said screw means are relieved, thereby freeing the fuses from the cups of the inner member and enabling ready removal of the outer body member by digital prehension with the fuses still in the cups of said outer member.

THOMAS E. McDOWELL. WILLIAM A. WULLE.

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