FR2473781A1 - SAFETY FUSE HOLDER - Google Patents

Abstract

A safety fuse holder for receiving a safe fuse when handling the fuse is disclosed. The fuse 27 is received in a cradle 30 intended to be introduced into an opening. The cradle has a retaining means 35, 36 which prevents it from being completely withdrawn from the opening. When it is in the maximum retracted position, a shutter 34, which may form part of the cradle, closes the opening to prevent the introduction of a fuse into this opening without putting this fuse in place on the cradle. Thus, the user cannot put the fuse in contact with a live part and be electrocuted. Application to fuses incorporated in sockets. (CF DRAWING IN BOPI)

Description

The present invention relates to a fuse holder for receiving a

  fuse by inserting it into an electrical circuit to be protected, and more particularly a fuse holder intended to equip a circuit where the fuse is placed at a point likely to be raised to a dangerous high voltage for a user in the event of direct contact ; it applies in particular to

  fuse holder fitted to electrical circuits connected

  dice to the alternative distribution network at 220 volts.

  In general, such a fuse can equip outlets, switches, various appliances (household appliances, industrial appliances), electrical distribution boards etc., and it is desirable that it is easily accessible to be

changed when it is defective.

  However, if it is easily accessible, it may be dangerous for the user who replaces it without turning off the installation.

general electric.

  More particularly, there are (especially on sockets) fuse holders made in the following manner: in an outer body having a front wall, a housing can receive by a

  opening in this wall before a cylindrical cartridge

  driques enclosing a fuse, contacts with a

  phase conductor of the plug and the current arrival

  being at the ends of the cylindrical cartridge.

  A screw cap can close the housing keeping the ends of the fuse in contact with the necessary electrical parts. The user must first insert the cartridge into the cap and then screw the cap into the slot, but there is the risk that instead he will insert the cartridge into the slot, pushing it with the finger, and that he screws the plug afterwards. When the cartridge is pushed to the bottom of the housing, it comes into contact with a phase conductor likely to be

  moment of tension and there is therefore a danger of electro-

the user.

  The present invention seeks to avoid this risk by providing a fuse holder in which it is not possible to have manual access to one end of the fuse when the other end is in contact with a conductive portion likely to be

  energized, this fuse holder being made economically

  and with as little space as possible (especially to be adapted to existing outlets where there is little

  place to house one or possibly two fuses).

  To achieve this, the present invention

  proposes a safety fuse holder intended to

  see a fuse to keep it in contact with an electrical part likely to be live and to allow the removal of the fuse, particularly with a view to

  replacement, safe when handling

  comprising an outer body having a front wall and a fuse receiving housing, the housing having an opening in the front wall, and a closure plug of this opening capable of closing the housing while holding the fuse in

  electrical contact with the electrical part

  it is possible to be powered up and with another electrical part in the housing, characterized in that it comprises a cradle of insulating material for receiving the fuse, this cradle being able to move inside the housing and being able to be partially withdrawn by the opening in the front wall, to a position where the introduction or removal of a fuse in the cradle is possible, the total withdrawal of the cradle being prevented by a cradle retaining means, the cradle with the back side (the

  more interior to housing) a part forming an ob-

  partial opening of the front wall, pocketing the penetration of a fuse into the housing

  until contact with the electrical part

  tible when the cradle is in a retracted position, and the cradle ultimately having an insulating protection portion at its

  part, which during the introduction

  duction of the cradle, penetrates inside the dwelling

  and pockets manual contact with the sensitive fuse.

  before the fuse comes into contact with

  the electrical part likely to be energized.

  It is preferably provided that the cap and the cradle form an insulating integral block, the plug constituting at the same time said anterior protection part which prevents manual contact with the fuse before it comes into contact with the fuse.

  electrical part likely to be energized.

  One can provide either a flexible cradle retaining strap, attached to both the cradle and the fuse holder body, and taking place during the removal of the cradle, a simple sliding retention portion

  with the cradle in the direction of introduc-

  of the cradle, a shoulder or a part of

  chage being provided for example on a part integral with the cradle and a shoulder or a part of attachment

  complementary to a part connected to the body of the holder

  fuse, the cooperation of the two shoulders

  killing the restraining means limiting the removal of the ber-

CWater.

  In the particular application where the

  fuse is incorporated in a socket to allow protection by a fuse (in the form of a cylindrical cartridge with two contact ends) of a contact socket capable of receiving a conductive pin intended for the transmission of

  current, it is expected that the fuse housing

  also holds the socket, accessible by the wall

  before as the fuse but by another opening.

  There is also provided a conductive elastic blade re-

  curved surrounding the fuse and its cradle and

  formed so as to comprise a part which comes opposite the socket opening of the front wall and which constitutes said contact socket capable of

to receive a pin.

  As regards the bringing into contact of the end (inner side) of the fuse cartridge with the live conductor, it is possible to provide an elastic contact blade fixed to the bottom of the housing (or a conductive part resumed by a spring), against which comes to rest the cartridge when put in place the plug in the housing. It can be provided in a variant that an elastic contact blade, capable of being applied against a conductive portion at the bottom of the housing when the cradle is completely inserted, is carried by the end

  posterior of the cradle. This elastic contact blade

  that is in the latter case preferably mounted with

  some sliding game in the sense of introducing

  ducting of the cradle into the housing to facilitate removal of the fuse from the cradle. In addition, the contact blade may have a shape such that it constitutes the partial shutter preventing penetration of a

  fuse when the cradle is removed.

  In the general case, it will be

  The partial section is formed by a protruding part molded with the cradle, at the rear part thereof. Other features and benefits of

  the invention will appear on reading the description of the

  Detailed description which follows and which is made with reference to the accompanying drawings in which: - Figure 1 shows a front view of a wall socket, an electrical appliance, or an electrical panel; - Figure 2 shows a side view of the socket of Figure 1; FIG. 3 represents an alternative embodiment

  current, view of the standardized type in the Republic

  as Federal of Germany; FIG. 4 shows in side section a

  socket incorporating a fuse holder for

  curity according to the invention in operating position; - Figure 5 shows a side section similar to Figure 4 in a position of introduction or removal of the fuse; - Figure 6 shows in perspective the fuse holder of the invention; FIG. 7 represents a perspective view of the curved conductive elastic blade forming contact between a socket of the socket and one end of the fuse and serving at the same time as a bayonet system for immobilizing the fuse holder cradle;

in closed position; -

  - Figure 8 shows a side section

  another embodiment of the invention, in posi-

  operation; FIG. 9 represents a side caster corresponding to FIG. 8, but in the position of withdrawal or insertion of a fuse;

  FIG. 10 represents a perspective view

  of the fuse holder according to the method of

  Figures 8 and 9; - Figure 11 shows another alternative form of cradle according to the invention; - Figure 12 shows in detail the shape of the bayonet contact element for holding the fuse in place - Figure 13 shows the fuse holder incorporated in a socket with the cradle of

  Figure 12 in the maximum retracted position.

  The invention will be described in detail in

  to a power socket incorporating a

  fuse, but it is understood that it also applies to other devices likely to be

  equipped with a fuse and as a result of

  safety fuse according to the invention.

  In Figure 1, we generally see in view

  face a socket 1 intended to be encas-

  in a wall or a painting with claws 2 that can hang on the back of a

  panel or collar surrounding the socket.

  The socket shown comprises two cells 3 and 4 for receiving conductive pins mAles and a ground pin 5, the two cells and the pin 5 being arranged in a triangle according to current French standards and opening on the front wall 10 of the socket. FIG. 1 also shows the location of an accessible fuse for disassembly via the front face of socket 1: this fuse is constituted by a cylindrical cartridge penetrating axially in a housing formed in the outer body 12 of the socket , the fuse being placed near the cell 4 and allowing the electrical connection of the cell 4 to a current supply inside the socket. The housing of the fuse opens an opening on the front face 10 of the socket 1, and this opening is closed by a plug 6 of insulating material provided by

  example of a diametrical groove 7 allowing the

  v-opening the cap by turning, using a

screw or coin.

  In Figure 2, we see in side view the socket of Figure 1, with the fixing claws 2 and at the rear of the socket electrical connections

  8 to be connected to electrical conductors

  phase and earth jacks when installing the pribe. One of the connections 8 is intended to be connected to a conductive part forming a bushing of

  contact inside cell 4, through the

  of a fuse contained in the housing-closed

by the cap 6.

  FIG. 3 is a front view of a variant embodiment made in accordance with a model of German standard in which two cavities 3 and 4 containing current transmission sockets are provided, and two symmetrical and sectioned earth pins 9. rectangular. A fuse is required for each socket in the cells 3 and 4 and we see in Figure 3 two plugs 6 placed on the front wall of the socket, each next to a respective cell and closing a fuse housing corresponding to the

socket of this cell.

  It is on sockets of this type (whether that of Figure 1 or that of Figure 3) that the

  This invention finds particular application

  cation but many other applications are

  can be used without departing from the scope of the invention.

  In Figure 4, we see in side section the detail of the fuse holder, incorporated into a socket, the

present invention.

  The body of the socket is designated by the reference 18; it comprises an apparent part, external to the panel or the wall on which the socket is fixed. The body 18 is extended at its rear part by a bottom 21 which incorporates the electrical connections used to. connect, when installing the socket, the socket-outlets or the earth pin to the current or earth leads of the installation. The bottom 21 is screwed onto the part -20 which itself has on its front face which constitutes the front wall of the socket, openings allowing the penetration of pins

  to the socket outlet, and also includes

  the ground pin and an introductory opening

  ducting of a fuse cartridge, accessible from

the front of the jack.

  In Figure 4, we see a cylindrical cell

  22 corresponding to the cell 4 of Figure 1. This

  vole emerges inside the body 21, in a space

  containing a contact "lyre" which is a conductive blade

  elastic band 23 (best seen in Figure 7).

  to form at its upper end 24 two branches having contact surfaces facing to form a conductive sleeve coming opposite the cell 22 and can grip with a close elastic contact a conductive male pin

introduced into the cell 22.

  It is sought to transmit a current to the socket constituted by the upper part 24 of the lyre 23, from an electrical connection 25 (connected to the distribution network and therefore likely to be live) located at the bottom of the fuse housing formed in the

  bottom 21 of the socket, the current transmission takes place

  killing through an elongated electrical contact

  26 and a fuse 27 in the form of a cylindrical cartridge having two ends of

contact 28 and 29.

  the end 28 of the fuse 27 comes

  when the fuse is in place, against the blade

  conductive contact 26 which itself comes into contact with

  bend against the 25 connection to the bottom of the body 21. The

  26.The blade may well be

  25 in the posterior portion of the bottom 21. In the example shown, the blade 26 has a curved shape with a free branch resting against the end 28

fuse.

  The other end 29 of the fuse is in

  tact with a conductive element 32 better visible at the

  FIG. 6, an element that forms a conductive contact

  with the lyre 23 to transmit the current in series from the connection 25 to the bushing 24-

passing through the fuse 27.

  The contact element 32 and the fuse 27 are carried by a fuse-holder cradle 30, made of insulating material, which is terminated at its anterior part by an insulating protection part 31 which constitutes in fact the plug 6 of FIGS. 1 and 3 but which could be separated from this plug. The protection part

  cap 31 is provided with a slot 33 permitting

  both to rotate it with a coin or a screwdriver. The entire cradle and fuse holder can be inserted into the body of the socket. The introduction is done against the elastic force of the conductive spring 26 and the locking in place of the assembly is preferably done through a bayonet system

  which allows to trap the whole by rotating the

  chon from a certain angle. Preferably, it is the contact element 32, carried by the cradle at the rear of the insulating protection part, which has a suitable shape (with side lugs) to cooperate in the manner of a bayonet system with notches in 33 provided in the lyre 23 (Figure 7). The bottom of the latter surrounds the fuse and its cradle so that the notches are located on both sides

from the cradle.

  The cradle 30 consists essentially of a portion of a cylinder corresponding to the cylindrical shape of the cartridge 27, this portion of the cylinder being terminated at its rear part (opposite the stopper 31) by a portion 34 of which one

explain the function below.

  Finally, it is expected (here below the cradle

  ) a tongue 35 extending parallel to the ber-

  30 and ending at its innermost end of the fuse housing of the socket by a shoulder 36. As seen in Figures 4 and 5, can be removed the cradle 30 by unlocking

  the bayonet system 32, 33 and removing the

  chon 31 to the outside of the socket, the tongue 35

  sliding when in the direction of removal of ber-

  until the shoulder 36 comes into abutment against a corresponding shoulder 37 integral with the body of the socket, thus pocketing a withdrawal of

  cradle fuse 30 beyond a certain disc

  tance. In Figure 5, there is shown the cradle

  fuseholder in the maximum retracted position, the

  36 in contact with the shoulder 37. In this position, the fuse is completely out of contact with the connection 25 or spring 26 which are likely to be undervoltage. In addition, it is possible to remove the fuse cartridge 27 for replacement and it is possible to introduce another inside the cradle 30, to then introduce the fuse in place in the socket by pushing the cradle 30 by the cap 31 and in

  locking the assembly thanks to the bayonet system.

  Finally, in the maximum withdrawal position of the cradle, it is not possible to introduce a fuse into the

  fuse housing of the plug without introducing it from

  edge in the cradle 26. In other words it is impossible to hold the fuse at one end with the fingers and make it penetrate to the live conductor (here the spring 26). The fuse is in fact stopped by the end 34 of the cradle which constitutes a shutter

  part of the opening of the introductory

  fuse in the housing, the size of this shutter 34 is such that the introduction space X left free by the shutter 34 is too small to allow the penetration of a fuse 27. It is therefore

  impossible to replace a fuse without the in-

  completely troduce in the insulating cradle 30, after which, the only way to put all the fuse and fuse holder in place is to push it through the insulating cap 31 by locking it by the bayonet system. Safety against electrocution when changing the fuse

is total.

  With the shape of the cradle and the sleeve in the form of an elastic blade surrounding the cradle, it is possible to adapt the safety fuse holder according to the invention to the German type sockets where it is necessary to have a fuse for each socket of current supply. In this case, fuses and cradles are constituted in a similar manner as well as the elastic blades forming bushings and surrounding

  each the fuse corresponding to the socket

  tive. The use of bushes in the form of resilient blades, whose bottom surrounds a fuse and its cradle and whose branches come to form elastic contact bushes opposite the pin insertion cells on the front face of the socket, allows to adapt the security system of the invention to German sockets with two fuses,

  without increasing the dimensions of the socket.

  FIGS. 8 to 10 show an alternative embodiment of the invention, similar to that of FIGS. 4 to 6, in that they also relate to a safety fuse holder incorporated in a socket, but slightly different from the embodiment of Figures 4 to 6 with respect to the one hand the cradle retaining means, and secondly the constitution of the partial shutter avoiding

  the introduction of a fuse directly into the box-

without going through the cradle.

  In FIGS. 8 to 10, the elements identical to

  those of FIGS. 4 to 6 are assigned the same references

  rences: this is the body 18 of the socket

  with a bottom 21 screwed onto a front part 20, of the

  vole 22 allowing the penetration of a pin to a corresponding socket, the lyre 23 still having the shape shown in Figure 7, with its end portion 24 constituting the contact sleeve, the

  conductive connection 25 likely to be under

  and adapted to be electrically connected via the fuse 27 to the socket 24, the fuse cartridge 27 cylindrical with its ends 28 and 29 and finally the cradle 30 for receiving the fuse cartridge 27 with its insulating protective cap 31 provided with a contact element 32 and a slot 33 for unlocking and locking

in operating position.

  the elements which are not identical to those of FIGS. 4 to 6 are first the tongue 35 serving as a retaining means for the cradle: it consists of

  a curved flexible strap which, instead of sliding

  simply in the direction of removal of the cradle being stopped by a stop, is here fixed both to the cradle and the body of the socket, and which, thanks to its flexibility, follows the movement of the cradle while rolling to the way of a caterpillar. Instead of being fixed to the front part of the cradle, as in FIG. 4, here the tongue has one end 38 fixed to the posterior part of the cradle, while its other end 39 is fixed between the body 20 and the bottom 21 that is, rather forward of the fuse housing. In fact, the other end of the tongue is simply wedged between the body 20 and the bottom 21 which are screwed to one another, the cradle, its cap and the tongue 35 being able to be made in one.

  plastic molded part, shown in

  10. In contrast to the embodiment of FIGS. 4 to 6, this molded part does not have a terminal spout at the rear part to constitute the partial shutter which pockets the direct insertion of a fuse without passing through the cradle when the cradle is out; the partial shutter function is here filled by a curved elastic blade attached to the posterior end of the cradle and also intended to make elastic electrical contact between the connector 25 and the end 28 of the fuse when the cradle is pressed into the operating position , cap 31 closed. This curved elastic blade is referred to by reference 26 '. As can be seen, this blade is held attached to the cradle 30 by one of its ends which is slid and wedged between the lower part of the cradle and the tongue 35. A sliding play J is provided to allow

  a displacement of the blade 26 'in the direction of introduction

  fuse to facilitate removal of the fuse when the cradle is pulled: the blade 26 'no longer applies forcefully against the fuse as soon as the cradle is sufficiently removed to stop contact with the connector 25 in the housing of the

fuse.

  Another variant embodiment is

  11 to 13. This variant relates to the shape of the cradle retaining means, to the shape of the conductive contact element 32 situated at the rear of the insulating protective part at the front of the cradle, and on the constitution of the electrical contact

  between the rear of the fuse (end 28) and the

  may be energized at the bottom of the dwelling

fuse.

  Regarding the cradle, visible in Figure 11 in perspective, we see that the retaining means is constituted by a rigid attachment portion 40 placed quite at the rear of the cradle and bending to come under the bottom of the contact lyre 23 when the cradle is removed (see Figure 13). The lyre then forms a stop because it can not move in the direction of removal of the cradle. Preferably, the hook 40 is guided to facilitate its passage under the lyre with side lugs 41 cooperating with longitudinal grooves not shown, formed in the side walls of the

housing of the fuse holder.

  The conductive contact element 32 is formed

  here a metal plate placed at the back of the

  chon (I protection 51, this plate having lateral ears to cooperate with the notches in

  L, 33, of the lyre in the manner of a bayonet system.

  This form of element 32 makes it possible to ensure good mechanical strength of the assembly (which must withstand the

  springs applying the electrical contacts

  at the ends of the fuse).

  The partial shutter, pocketing the introduc-

  tion of a fuse without passing through the cradle when it is in a retracted position, here is constituted by a spout 34 molded with the cradle and located

  at the back of it.

  Finally, the electrical contact part 25 that may be under tension, and against which

  the posterior end 28 of the fusillator

  ble when in place (cap 31 closed), is constituted by a conductive pin U placed at the bottom of the fuse housing and recalled by a spring

  25 'to the fuse. Thus, we are not obliged to use

  a high-cost (beryllium bronze) removal conductor blade, given the significant contact

  provide between driver and fuse.

Claims (14)

  1. Safety fuse holder for receiving a fuse to keep it in contact with a part   electrical power likely to be energized and   the removal of the fuse, particularly with a view to its replacement, without danger during handling, comprising an outer body having a front wall and   a housing for receiving a fuse, the housing   an opening in the front wall, and a closure cap of this opening capable of closing the   housing by holding the fuse in electrical contact   with the electrical part likely to be live and with another electrical part in the housing, characterized in that it comprises a cradle of insulating material for receiving the fuse,   this cradle can move inside the box-   partially removed by the user.   in the front wall, to a position where the insertion or removal of a fuse in the cradle is possible, the total withdrawal of the cradle being prevented by a cradle retaining means, the cradle   with the rear side (the innermost in the box)   partially obturator part of the opening.   the front wall, preventing the penetration of a fuse into the housing until contact with the   electrical part likely to be live when   that the cradle is in a retracted position, and the cradle finally having an insulating protective portion at its anterior part, which part, during the introduction of the cradle, penetrates inside the housing and prevents manual contact with the fuse substantially before the fuse comes into contact with the electrical part likely to be live. 2. Fuse holder according to claim 1, characterized in that the plug and the cradle   form an integral insulating block, the plug constitutes   killing at the same time said anterior portion of   which prevents manual contact with the fuse before the fuse comes in contact with the   electrical power likely to be energized.   5. Fuse holder according to one of the claims   1 and 2, characterized by the fact that a flexible strap   is attached to both the cradle and the body of the holder   fuse to constitute the restraining means limiting the removal of the cradle.   4. Fuse holder according to one of the claims   1 and 2, characterized in that there is provided a hooking part on a part connected to the cradle and a hooking part on a part connected to the body, these two hooking parts cooperating with each other when the cradle arrives at its maximum withdrawal position, to constitute a limiting restraining means the removal of the cradle.   5. fuse holder according to claim 2, characterized in that the cap is likely to be maintained in closed position by a bayonet system.   Fuse holder according to one of the claims   1 to 5, incorporated in a socket to allow protection by a fuse of a socket contact   electrical connector capable of receiving a conductive pin   trice intended for the transmission of a current,   terized by the fact that the fuse housing contains   also the contact socket, which is   sible by another opening in the front wall of the   body and that an elastic blade is provided   curved conductor, surrounding the fuse and its cradle and shaped so as to have a part yes is opposite the socket opening of the front wall and which constitutes said bushing of   contact likely to receive a pin.   7. Fuse holder according to claim 6, characterized in that the elastic blade has a shape having a bottom surrounding the fuse and the cradle and branches extending until the sleeve opening, the ends of the branches having contact surfaces facing each other by forming between them a space suitable for allowing the insertion of a pin and a contact   between the branches and the spindle.   8. Fuse holder according to one of the retrendica-   6 and 7, characterized by the fact that the cradle bears, behind the insulating protection part,   an electrical contact element touching an end   contact of the fuse when it is in place in the cradle and touching the curved elastic blade when the cradle is inserted in place in the accommodation.   9. Fuse holder according to claim 8, characterized in that the electrical contact element comprises side lugs cooperating in the manner of a bayonet system with L-shaped notches formed in the resilient sleeve forming blade, to ensure maintaining the cradle and   fuse in operating position.   10. Fuse holder according to one of the claims   6 to 9, characterized in that the socket has two similar current supply sockets,   each protected by a respective fuse and   each to receive a conductive pin   introduced by the front wall of the catch, the fusi-   also being accessible by the front wall of the socket, the fuse cradles being similarly constituted and each surrounded by a respective resilient blade, part of which forms the socket corresponding to this fuse.   11. Fuse holder according to one of the claims   1 to 10, characterized in that there is provided at the bottom of the housing a conductive portion capable of being under tension and a conductive spring fixed to the bottom of the housing, in contact with said conductive portion, spring against which comes to rest by making contact with him the posterior end of contact of the fuse.   12. Fuse holder according to one of the claims   1 to 10, characterized in that there is provided at the bottom of the housing a conductive portion capable   to be energized, recalled by a spring in direct   tion of the rear contact end of the fuse to make contact with this end when the fuse is in place.   13. Fuse holder according to one of the claims   1 to 10, characterized by the fact that the cradle carries at its posterior end a conductive elastic spring capable of coming against a   part.conductor at the bottom of the house and against the ex-   tremit4 posterior fuse contact when the   cradle has completely returned to the housing.   14. Fuse holder according to claim 13,   characterized by the fact that the spring worn by the former   posterior tremity of the cradle forms the shutter par-   tiel pocketing the penetration of a fuse.   15. Fuse holder according to one of the claims   1 to 14, characterized in that the partial shutter part of the opening of the wall-before to prevent the introduction of a fuse is a posterior edge of the cradle, molded in one piece with the cradle.   16. Fuse holder according to one of claims 1 to 15, characterized in that the cradle retaining means is a curved hook-shaped portion at the rear of the cradle, this part being able to catch, when removing the cradle, for example on the elastic blade forming a sleeve when such blade is present.