US2072730A - Fused safety switch - Google Patents

Description

March 2, 1937.

A. CORBETT 2,072,730 FJSED SAFETY SWITCH Filed D80. 6, 1935 4 Sheets-Sheet l I 28 f7 I is H 1 (3 O O O 3/) CO v TTORNEYQS March 2, 1937. A. CORBETT 2,072,730

FUSED SAFETY SWITCH Filed Dec 6, 1935 4 Sheets-Sheet 3 ATTORN EYS 4 Sheets-Sheet 4 A. CORBETT FUSED SAFETY SWITCH Fi led Dec. 6, 1935 March 2, 1937.

A V i f w a. z wmmwmmvvmwh INVENTOR 6 m BY 5% ma MM ATTORNEYS 15 desirable that vg receptacle.

V30 conductors to the 35f switch, considered as a whole,

Patented Mar. 2,1937

PATENT OFFICE 7 2,072,130 FUSED SAFETY SWITCH' Alfred Corbett. n-win, n,

Electric Products Corporati Delaware assignmto Nationalon, a corporation of Application December 6, 1935, Serial No. 53,174 9 claims. (oi. 200-114) the switch, within the cabinet, to protect a greater This invention relates to a fused safety switch, to the combination of a fused safety switch with, specialized means for leading electrical power to and from the switch,

' switch with a fuse cabinet pe- In fused switch assemblies in which fuses are associated with switching means to protect line circuits, or special circuits, 'such as range circuits, l0 it is of importance that the fuse-containing'assembly be of relatively restricted dimensions, in order that it may be housed in a cabinet of moderate size, while leavin within the cabinet working space for the connection of conductors. It is fused safety switches be formed of a receptacle element and a cover element, with the fuse mounted on the under side of the cover. element, and with the cover element hinsedly mounted to the receptacle. The disadvantage with a structure, as so generally described, is that the hinging of the cover to the receptacle causes the cover to occupy what is considered in the art to be an unreasonable space, when the cover is in its open position to expose the interior of the This either necessitates the use of a fuse cabinet of relatively great size to accommodate the switch in both its positio or, in a fuse cabinet of restricted dimensions, gives cramped space within the cabinet for the attachment of fused switch. With these problems in mind, I have invented a fused safety switch in which a fuse-carrying cover element is so pivoted to its associated receptacle that in open position occupies a mini- 'mized space;'and with this fused safety switch I have associated a containing cabinet so formed and arranged as to he peculiarly adapted to the accommodation of my fused safety switch, and 40 also to occupy itself a minimized space while providing interiorly of the cabinet abundant free working space for the attachment of conductors to the fused switch. This fuse cabinet I also have made of such form and arrangement that, when 45 the fused safety switch is mounted therein, the

assembly presents a compact and pleasing appearance.

In evolving the fused safety switch of my invention, and my combination of fused safety 50 switch and containing cabinet for it, I have succeeded in associating with the switch inlet connector elements of unitary structure, and have also associated in the cabinet and with the switch unitary fuse-mounting elements so constructed, 65 and arranged that they may be integrated with and to the combination ofv of the cover the or lesser number of branch circuits, without alteration in or removal of the fused safety switch itself.

' In the unitary connector structures for leading of! branch circuits from the switch I have also incorporated tamper-proof structures of known form in such manner that they are not removable from mounted position without removing the switch assembly from the cabinet and disintegrating the assembly by detachmentof its outlet connector elements.

The structure and arrangement of my fused safety switch assembly is such as to adapt the switch to varied service in the fused protection of circuits, andwithout substantial alteration in the structure of the switch itself to permit its ready adaptation to various service requirements.

In the accompanying drawings Fig. I is a front elevation, showing the cabinet and fused safety switch of my invention with the safety switch and branch circuit fuses exposed by open position of the cabinet door, and with the remaining spaces within the cabinet enclosed.

mg. II is an end elevation of the cabinet shown inFig. I.

Fig. III is a view, looking in the direction of the arrows I1I-I1I of Fig. I, showing the assembly of the cabinet and the fused safety switch therein, walls of the cabinet being partially broken away to show in side elevation the safety switch .contained within the cabinet.

Fig. IV is a plan view of the receptacle portion of my fused safety switch, cover elements therefor being omitted, showing, switch proper, added connector elements for inlet connection and outlet connection by way of fused branch circuits from the switch, and showing in dotted lines buss connectors associated directly with the switch.

Fig. V is'an exploded side elevational view, on

a slightly enlarged scale, illustrating surface contours only, of the receptacle portion of my fused safety switch proper, and unitary inlet and outlet connector elements for integrated association with the receptacle of the switch proper.

Fig. Va is a side elevational view, on the scale of Fig. V, showing in side elevation the cover element of my fused safety switch, and showing fuses of the cartridge type mounted on the under face thereof for presentation to the interior of an associated receptacle.

associated with the Fig. Vb is an end elevation of the cover element' I shown in Fig. Va.

Fig. Vc is an end elevation showing, on a scale larger than that of Figs. V, Va, and Vb, a structural base element or block adapted for integration with the fused safety switch to provide for the mounting and connection of the sockets for 6 branch circuit fuses at the outlet end of the switch.

Fig. Vd is, on the scale of Fig. Vc, a view of two structural elements or blocks adapted for mounting on the base block of Fig. V to receive and house fuse sockets mounted on the base block of Fig. Va and to house fuses received in such sockets, one of the said structural shield blocks being shown wholly in end elevation, and the other of the said blocks being shown partly in end elevation and partly in vertical section;

Fig. Ve shows in end elevation, on the scale of Fig. Vc, two structural elements or blocks adapted to be integrated with the receptacle of the fused switch to provide inlet connection thereto.

0 Fig. VI is a transverse, vertical, sectional view, taken on the irregular section line VI-VI of Fig. IV, illustrating, on a still further enlarged scale, the structure within the receptacle at one side of the switch, as shown in Fig. IV, with the cover shown thereon in closed, circuit-completing condition of the switch, and taken vertically through an end wall of the receptacle at the other side of the switch structure. K

Fig. VII is a. longitudinal, vertical sectional view, on the scale of Fig. VI, taken on the section line VII VII of Fig. VI, and showing in broken lines an intermediate position of the cover in rotation of the cover to expose the interior of the receptacle; this view also illustrating in longitudinal, vertical section the integration of the unitary structural blocks forming inlet and outlet connectors for the switch, and showing a tamperproof socket mounted on the base block at the outlet end of the switch and housed in a shield block assembled on the base block.

Fig. VIII is a plan view of a modified safety switch assembly, shown on the scale of Fig. IV, showing. the switch as of single construction, rather than as of the double construction shown in preceding figures of the drawings, and showing mounted at both ends of the switch the simple form of connector block illustrated as an inlet connector in the preceding figures of the drawings.

Fig. IX isa. plan view. similar to Fig. VIII, and on the same scale, but showing at the outlet end of'the switch proper a base block for the mounting of branch circuit fuse sockets formed sub stantially as one-half the base block shown in Fig. Vc.

Fig. X is an end elevation of the single unit base block shown in assembly in Fig. IX.

Fig. XI is a view, taken in vertical, longitudinal section, on the scale of Figs. VI and VII, illustrating a modification in the barrier structure of the switch arranged fully to shield the contacts in the receptacle of the switch during movement of the'cover to open position, and illustrating an intermediate stage in such movement in order to illustrate the shielding of the contacts.

Fig. XII is a cross-sectional view through the switch, taken on the section line XIIXII of Fig. XI.

Referring to the drawings, reference numeral designates generally the cabinet for containing the safety switch, which is shown with its door 2 in open position, exposing to view two separately operable switch units 3 and 4, and plug fuses 5 .for the protection of branch circuits taken off from the switches.

Referring now particularly to-the structure and arrangement of the switch assembly itself, it is to be noted that the two switches, designated respectively by reference numerals 3 and 4, are shown as associated together, and having a common neutral bar 6. It should' be initially explained that the direct association of two switch units, one of which may protect the line circuit, and the other of which may protect a special circuit, such as a range circuit, may be made either by the use of an integral molding for the receptacle elements of the two switch units, or by forming the receptacles of the two switch units sep arately, and integrating them in the assembly. Also, as will appear, one of the switch units, comprising an assembly of receptacle, cover, and con.- nectors, may be independently used. Also, in line with this thought, more than two switch units may be assembled together, either by the use of a molding comprising more than two receptacles, or by the integration of more than two initially separate receptacles.

Referring particularly to the structure of the switch, best shown in Figs. V to VII, inclusive, of the drawings, each of the receptacles l is formed of insulating material, molded or otherwise formed into an integral body having a bottom wall 8, end walls 9 and I0, and side walls II and I 2, the side wall I2 being, as shown in these figures of the drawings, common to the two receptacles of the assembly. At its longitudinal center line the receptacle is divided into two chambers of substantially equal area by a barrier l3, which is integrally formed with the body of the receptacle. In one of the chambers defined by the barrier l3 are spring contacts I 4 and I5, and in the other of the chambers are spring contacts is and I! of polarity opposite to that of the spring contacts i4 and I5. Associated with spring contacts 14 and I6, at the inlet end of the receptacle, are fiber shields i8, arranged to extend upwardly along that element of the spring contacts which lies inwardly of the receptacle. The spring contacts l5 and I! may, for the reason hereinafter explained, be unshielded. The cover 20 of the receptacle carries on the under face thereof spring clips 2| and 22,- adapted to receive and engage cartridge fuses 23. Conductively associated with the cartridge fuses 23 on the under face of cover 20 are contact blades 24, 25, 26, and 21, the contact blade 26 being cut off from view by contact blade 21 in Fig. Vb and by contact blade 24 in Figs. VII and Va. v In closed, circuit-completing condition of the switch the circuit is completed on one side of barrier l3 by spring contacts I4, contact blade 24, the cartridge fuse 23 interconnecting the two spring clips 2|, contact blade 25, and spring contacts IS. The completion ofa conductive assembly through the cartridge fuse 23 at the other side of barrier I3 is identically effected by the elements assembled at that side of the fuse.

Cover 20 is articulated to the body of receptacle I, so that itmay be swung into open position to expose the interior of the receptacle, and to expose the fuse-attaching elements and the fuses carried on the under face of the cover. For swinging movement, cover 20 is provided with a handle 28, which is shown as of simple form, but which may be of any suitable specialized form if so desired, and is mounted on a pintle 30, trunnioned in the side walls of the receptacle. As best illustrated in Fig. I of the drawings, pintle 30 is common to the covers 20 associated with both the switch units, being mounted in upwardly extended lugs 3|, formed on the outer side wall ll of the receptacle, and lying in a groove 32 (see Fig. IV) in the common side wall ii. The pintle is overlaid at the common 5 side wall I! by a strap If shown in Fig. I. Pintle 30 is thus so engaged by groove 32 and strap 33 that it is held against longitudinal movement and against rotation. Returning to a consideration of one of the two 0 receptacle and cover assemblies shown in duplicate in these figures of the drawings, it will be noted that pintle 30 extends through the body of the cover 20 forwardly-l-thatis, to the left in Fig. VII-of the rearward edge of the cover, and that it is slightly above the upper edges of the outer side wall ll of the receptacle. The cover thus'has a center of rotation intermediate its ends and substantially removed forwardly from its rearward end, so that in swinging movement 0 of the cover into open position the rearward region of the cover follows a path extending into the hollow interior of the receptacle, and in fully open position the rearward region of the cover overlies the rearward region of the receptacle. It will be noted by an inspection of the drawings, that the positioning of the pintle'lll is such as to cause the cover, in its open position, to overlie the receptacle to the maximum extent possible without increasing the depth of the receptacle.

In order, at the rear of the switch structure; to permit turning movement of the cover, barrier I3 is provided with an arcuate recess 35 centered on the pintle iii, and a barrier portion It depends from the under face of the cover in alignment with the barrier ll. This barrier member 38 is of segmental form, and also has its edge formed on an arc centered in the pintle Iii. In receptacle-closing position of the cover, barrier member 38. therefore lies inthe 40 recess 35 of barrier II to form a complete. barrier extended from end to end of the receptacle.

In opening movement of cover 20, the equally curved surfaces of recess I5 and barrier member 36 permit free turning movement of the cover. '45 At the forwardxor inlet end of the switch, the

forward wall 0 of the receptacle may be chamfered as at 31, and the lower forward edge of the cover may be chamfered as at 007 to permit turning movement at the forward end of 50 the cover within the overall thickness of the front wall 9. I

It will be appreciated that, with the cover 20 swung further than its position as shown in Fig. VII, the cover in its reversed position overlies 55 almost half the length of the receptacle. In

addition to economizing in the overall longitudinal dimensions of the switch when the cover is in open position, the'cover, when opened, thus also screens spring contacts l5 and IT at the outlet end of the receptacle, and for this reason it is unnecessary that these contacts be provided with insulating shields, such as the insulating shields II which shield spring contacts I4 and ii at the inlet end of the receptacle.

grated with the switch proper by attachment both to bus bars leading to and from the switch. To this end, I provide inlet connector blocks 80, and outlet connector or base blocks 40. Ex-

tending longitudinally in each of the inlet con- 15 nector blocks 39 are a pair of stepped recesses matching It being necessary to provide for electrical of the,connector units and the switch proper "0, adapted to receive line connectors II, and for the mounting of bars 42, of opposite polarity, leading to the spring contacts I and I, through slots 43 in the end wall 8 of the switch. Beneath inlet connector block 39 are hollow feet or thimbles b to receive the heads of screws 44 for attaching conductors to the block. Each block is also provided with an additional foot c, in line with a bore 39d, through which may extend the screw for securing the block in the fuse or switch cabinet in which the assembly is mounted. These feet on the connector are of equal height with screw-receiving feet 1a formed at the under side of the receptacle 1. It will be noted that in the double form of switch shown in Figs. 1 to VII, inclusive, of the drawings, two inlet connector blocks unit of the structure. The formation of the inlet connector blocks 39 as units, each of which is adapted for integration in a switch unit, permits these blocks to be used without change in either a single switch assembly or a multiple switch assembly.

At the outlet end of the receptacle 1, the outlet base blocks are integrated. These base blocks 40 desirably are formed to extend across the entire width of the double switch receptacle, to-

provide for cross connection between the switches in the manner which is to be described. Each of the blocks has thereon feet 400 and 40b of a height equal to the feet on the receptacle I and on the inlet connector block 39. Of these feet, the feet "b have therethrough central bores 'to receive screws for mounting the base blocks to the fuse or switch cabinet. Recesses 40c extend forwardly from the rearward edge of the block in the lower region of the block, these recesses being adapted to receive conductor bars 45, leading from spring contacts within the receptacle through slots in the end wall "I of the receptacle. A similarly formed, but intermediately positioned, .pair of recesses 40d are adapted to. receive conductor bars 46, also passed through slots in the end wall in of the receptacle from spring contacts within the receptacle.

As shown, the recesses 40c and 40d do not extend wholly through the block 40, so that the block 4. is adapted solely to use as a final base block at the outlet end of the receptacle. If it is desired to use two or more base blocks, in order to provide mounting for an additional number of branch circuits taken off from the switch, intermediate base blocks are inserted between the outer or final base block 40, and the receptacle of the switch.. Such base blocks, for intermediate use, differ from the base block 40 only in the fact that the recesses lie and 40d are extended throughout the entire width of the block to provide channels through which the conductor bars may be extended into an additional outlying block or blocks.

Base block 40 is provided with a plurality of apertures 40c, one leading from each of the recesses in the base block to the upper surface of the block. These bores receive bolts, or the like, 41, making connection with conducting bars I and 40, and serving each-as the center contact of a socket for a plug fuse guarding a branch circuit. The fuse sockets shown areof the tamper-proof type, each comprising a screw shell 8, which has fixed therein a tubular structure 40, containing a conducting plunger 80 urged away from the center contact by a coil spring I. These structures, which in themselvesdo not form part of my invention, are adapted,

upon the insertion of plug fuse 5, to complete connection between the center contact provided by bolt 41, and the screw shell 48.. From each of the screw shells 48 a branch conductor 'bar 52 leads to a terminal post 52a.

Since the tamper-proof nature of the fuse socket renders the central connections of the socket inaccessible when the tubular guard 49 is permanently secured in the screw shell 48, it is highly desirable that the means for housing and shielding the sockets be formed of an integral element or elements mountable on and removable from the base block 40. These housings or guard blocks 53 are shown as formed integrally each to house two fuse sockets in vertical bores 53a extended through the blocks. Each of the blocks has through the forward wall thereof slots 53b to lead to the branch-conducting bars 52 from the fuse sockets into a terminal receiving space lying between abutments 53c. Through each of the blocks 53 is a screw-receiving bore 53d, which is adapted in assembly to align with the bore terminating in one of the feet 40b of the base block 40, this alignment providing through passage for a screw making connection between the blocks 40 and 53 by through attachment to the base of the fuse or switch cabinet in which the assembly is mounted.

This outlet structure readily adapts itself to multiplication for leading off additional branch circuits. base blocks the slightly modified form of block described above/base blocks 40 and housing blocks 53 may indefinitely be multiplied along the neutral bar 6 associated with the switch structure, and along extended conductor, 'or buss, bars 45 and 46. Also, this unit construction of the outlet connectors adapts itself readily to the use of tamper-proof fuse sockets, of the type indicated above, to protect the various branch circuits which are led off. b

To describe an outlet connection, usable with the unit switch assembly shown, reference is to be had particularly to Figs; IV, VI and VII of the drawings. In Fig. IV it will be seen that the conducting bars 45 are interconnected at the receptacle by means of a U-shaped conducting bar 54, which interconnects the spring contacts I of one receptacle assembly and the spring contacts I! of the other receptacle assembly; The intervening conducting bars 46, leading from the spring contact H of one receptacle'assembly, and the spring contact I5 of the other receptacle assembly, are interconnected between the fuse sockets which they sgve by conducting bar 55. Appropriate electrical connection may be made in various alternative ways, since unit construction of the outlet connector blocks lends itself to variety in the efiective connection of branch circuits, as well as to multiplication in the branch circuits taken off, with the change in the form of any of the structural elements.

Turning now to the fuse or switch cabinet I,

and to the mounting of the switch structures in the cabinet, it will be seen that the door 2 of the cabinet encloses an intermediate region only of the cabinet, and that this door 2 is a structure arranged to project outwardly from the cabinet body Ia. This arrangement of the cabinet door 2 permits the switch structure proper to be enclosed within the compass of the cabinet whether the cover of the switch be in closed position orin open position. Thelength of the protuberance provided by the cabinet door 2 is, however, minimized by the mounting of the switch cover 20.

This because, utilizing as intermediate In installation, the base portion Ia of the cabinet may be inset from the surface of a wall with its outer facelying flush with the wall surface, so that merely the protuberance formed by the door 2 projects outwardly beyond the surface of the wall.

The means for enclosing the interior of the cabinet to both sides of the door 2 are detachable cover members 56 and 51, which have on each thereof peripheral flanges 58 embracing the wall of the cabinet body Ia. Inwardly of the cabinet the cover element 56 has a dependent flange or wall 59, separated from the embracing flange 58 by slots. This construction permits wall 59 to lie between the body walls embraced bythe flange 58, providing a finishing stub partition interiorly of the'cabinet cooperative with the adjacent edge of the door 2, and providing an interlocked engagement between the cover element and the body of the cabinet.

Cover element 5! has thereon a generally similar interiorly'depending wall 60, which is similarly separated by slotting from the flange 58 of this cover element. Wall 60 is, however, inclined longitudinally of the assembly, and is extended in forward inclination to a line at which it contacts the upper surface of socket-embracing blocks 53. This arrangement of the door and cover element separates the space occupied by the switch and plug fuses from the remaining space within the cabinet, and presents a particularly finished and attractive appearance when the door of the cabinetis open.

It will readily be understood that the fundamental form of the fuse or switch cabinet and its cooperative relation to the switch assembly may be preserved in installations in which additional connector units are added to the switch assembly, for taking off additional branch circuits. This involves merely such changes in the proportions of the cabinet elements that one or more rows of fuses 5 are exposed inwardly of the inclined partition wall 60 of the cabinet cover element 51.

Fig.' VIII of the drawings shows a substantially identical receptacle structure formed as a single switch. This single switch receptacle, designated generally by reference numeral BI, is adapted for use merely as a line switch, either fused or unfused, by mounting at the outlet end of the switch an inlet block 39 identical with the inlet block by which inlet connection is made to the switch.

I In this form, in which fuse mounting for branch circuits is not directly associated with the switch, the structure of the switch, as to its receptacle and cover structure and arrangement, is substantially identical with that previously described, the cover being mounted on the receptacle to turn about an axis intermediate its length, and the receptacle and cover being provided with barriers I 3 and 36, identical with the similarly designated elements shown in the preceding figures of the drawings. In this single switch structure also only the spring contacts I4 and I 6 at the inlet end of the receptacle need be guarded by feet 620. disposed at the'side-edges of the block, and a foot 62b through which extends a bore for a mounting screw. It has extended forwardly from its rearward edge recesses 620 for the reception and attachment of conducting bars. 4

In both the showing of Fig. VIII and the showfused branch circuits taken of! from the switch In Figs. XI and XII, there is illustrated a modification in the switch structure designed particularly to prevent danger to an operator of the switch while moving tween its open and closed positions. This modified structure is shown as incorporated in a single switch, corresponding generally to the switch shown in Figs. IX and X of the drawings, but it is to be, of course, understood that it is applicable to an arrangement comprising two or more switch units.

Referring to these figures of the drawings, it is in the upper edge contour of the barrier, therein shown, that the modified receptacle structure resides. This barrier 65 has in its upper region an arcuately defined recess 65a,

' corresponding to the arcuate recess 35 previously lapping of the cover .not pass upwardly described as formed in barrier l3. Forwardly of recess 65a there is a region 65b which lies within a groove 66a in cover 66. Forwardly of this region 65b is a region 65c in which the barrier 85 is extended still farther upwardly to lie in a through slot 66b in the cover 66'.

Dependent from adjacent the inlet end thereof, are two insulating wings 61 arranged, in closed position of the cover, to embrace the inlet region of the barrier adj acent the spring contacts II and I6 therein. The over- 68 with barrier 65, by means of the slotted embracement of barrier portion "0, together with the downward extension of insulating wings 61, is such that, in opening movement of the cover, the cover structures do beyond the barrier until contact blades 24 and 26 have been wholly with drawn from contact with the spring contacts I4 and Hi. This arrangement provides means in the primary partsof the assembly for shielding the contacts, and thereby prevents accidental bridging across the sw itch during opening movement of the cover.

Similarly, in swinging the cover from open position to its closed position, the contact blades 24 and 28 do not come into contact with the spring contacts II and I6 before the insulating wings 61 to some extent overlap the barrier portion 850 which they embrace. With this struconly against ture, the operator is protected not danger under ordinary conditions, but is also protected -against extraordinary conditions which conceivably may arise.

It will be noted that the receptacle element of the switch is so formed that for most simple connections it may be reversed, the outlet end of the switch becoming the inlet end thereof, and viceversa. The terms "inlet and outlet have been used throughout the specification for purof convenience in describing the location of the various switch parts. These terms are to the switch cover bethe under face. of the cover be read in the light of the showing of the drawings, and are not to be considered terms of limitation as defining a fixed relationship of switch parts in the switch proper peculiarly for either inlet or outlet connection. It is also to be understood that my safety switch, and all the various modifications illustrated, may be used as an unfused switch by interconnecting the blade contacts on opposite sides of the cover by simple conductors rather than by fuses. In such case, also, suitable fuses may be mounted, and electrically connected in the receptacle rather than on the cover to be made a part of through circuits by the cooperation of the cover-carried contacts.

It has been noted in an early portion of the specification thata multiple switch assembly may be made up by integrating together unitary receptacles, such as the receptacles shown in Figs. VIII and XI, instead of forming an integral multiswitch receptacle. The description of the fundamental structure, and modifications, hereinabove contained, renders clear how, this may readily be done.

Throughout the drawings the structural parts have been shown of a wall thickness appropriate to the use of porcelain as the material out of which the primary elements are made. be understood that, if these parts are made of some suitable hot molded insulation, such as the molding resin compositions, the thickness of the bases and walls can be substantially reduced, thus further reducing the compactness of structure obtained in principle by the shape and arrangement of the parts.

It will readily be understood that such various modifications in and adaptations of my switch do not affect the novel and advantageous features which I have succeeded in incorporating in a switch of the sort involved, and which have with particularity been described and explained above.

I claim as my invention:

1. In a safety switch assembly the combination of a hollow insulating receptacle, contacts mounted in the receptacle and spaced longitu- It will H dinally of the receptacle in cooperative pairs, an

insulating cover for the receptacle having on its under face contacts electrically interconnected longitudinally of the cover in pairs each of which in closed position of the cover electrically interconnects a longitudinally spaced pair of contacts in the receptacle, said cover being arranged in closed position to overlie substantially the entire cavity of the receptacle, and trunnions intermediate the length both of the cover and the receptacle and arranged for turning movement of the cover about a fixed axis whereby when swung to open position exposing the contacts on the under face of the cover regions of the cover lying adjacent the turning axis to both .60 sides thereof partially overlie the interior of the receptacle to shieldcontacts at one end of the receptacle.

lating the cover to the receptacle to turn about an axis intermediate the length of the cover thereby to overlie a region of the receptacle in open position of the cover, a recess in the barrier of the receptacle having an edge formed on an are centered in the axis of the cover, and a depending wall on the cover having an edge also formed on an are centered in the axis of the cover, said wall and recess cooperating to permit swinging movement of the cover to fully open position and cooperating to form in closed position of the cover a complete barrier from end to end of the receptacle. 7

3. In a safety switch assembly the combination of a hollow insulating receptacle having mounted therein cooperative contacts spaced from each other longitudinally of the receptacle, an insulating cover for the receptacle having on the under face thereof contacts electrically interconnected longitudinally of the cover and positioned on the cover in closed position thereof electrically to interconnect the longitudinally spaced contacts in the receptacle, an insulating block arranged to carry inlet connection to at least one contact at the inlet end of the receptacle, and at least one separately formed insulating block adapted for integration with the switch receptacle at the outlet end thereof and adapted to carry both outlet connections to at least one contact at the outlet end of the receptacle and to carry a fuse socket for the fusing of a circuit led off from said outlet connection, and at least one separately formed insulating block adapted for integration in the assembly by attachment to the block carrying the fuse socket and arranged to house a fuse socket carried by said first-named block.

4. In a switch assembly the combination of a switch receptacle having an outlet conductor projected therefrom, a separately formed insulating block adapted to receive said conductor in a region below the upper surface of the block, a fuse socket mounted on said insulating block and having a contact structure projected through the said block and connected with the conductor housed therein, said fuse socket having fixed therein means screening the said contact structure from above, and a separately formed insulating block arranged to receive and house said fuse socket and adapted for integrating attachment to the insulating block carrying the fuse socket.

5. In a safety switch assembly the combination of a hollow insulating contact-containing receptacle, and an insulating contact-carrying cover, said cover being arranged in closed position to overlie substantially the entire cavity of the receptacle, and trunnions intermediate the length both of the cover and the receptacle and-arranged for turning movement of the cover about a fixed axis, whereby in its open position the.

cover partially overlies the cavity of the receptacle.

6. In a safety switch assembly the combination of an insulating contact-containing receptacle, and an insulating contact-carrying cover articulated to turn about an axis intermediate the ends of the cover thereby partially to overlie the receptacle in'open position of the cover, with an insulating block arranged to carry inlet connection to at least one contact at the inlet end of the receptacle, and at least one separately formed insulating block adapted for integration with the switch receptacle at the outlet end thereof and adapted to carry outlet connection to at least one contact at the outlet end of the receptacle and also to carry a fuse socket for the fusing of a circuit led off from said outlet connection, and at least one separately formed insulating block adapted for integration in the assembly by attachment to the block carrying the fuse socket and arranged to house a fuse socket carried by said first-named block.

7. In a safety switch assembly the combination of an insulating contact-containing receptacle, and an insulating contact-carrying cover articulated to turn about an axis intermediate the ends of the-cover thereby partially to overlie the receptacle in open position of the cover, an outlet conductor projected from the said contact-containing receptacle, a separately formed insulating block adapted to receive said conductor in a region below the upper surface of the block, a fuse socket mounted on said insulating block and having a contact structure projected through the said block and connected with the conductor housed therein, said fuse socket having fixed therein means screening the said contact structure from above, and a separately formed insulating block arranged to receive and house said fuse socket and adapted for integrating attachment to the insulating block carrying the fuse socket.

8. In a fused safety switch assembly the combination of an insulating contact-containing receptacle, an insulating cover carrying fuse-interconnected contacts cooperative with the contacts of the receptacle electrically to interconnect the receptacle-contained contacts through the covercarried fuse in closed position of the cover, and means articulating the cover to the receptacle to turn about the axis intermediate the ends of the cover thereby in open position of the cover partially to overlie the receptacle, with at least one separately formed insulating block adapted for integrationwith the said contact-containing receptacle at the outlet end thereof and adapted to carry outlet connection to at least one contact at the outlet end of the receptacle and also to carry a fuse socket for the fusing of a circuit led off from said outlet connection, and at least one separately formed insulating block adapted for integration in the assembly by attachment to the block carrying the fuse socket and arranged to house a fuse socket carried by said first-named block.

9. In a safety switch assembly the combination of an insulating contact-containing receptacle, and an insulating contact-carrying cover articulated to the receptacle to turn about an axis intermediate the ends of the cover thereby partially to overlie the receptacle in open position of the cover, with at least one separately formed insulating block adapted for integration with the said contact-containing receptacle and adapted to receive and mount electrical outlet connection to at least one contact contained in the said receptacle.

ALFRED CORBETT.

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