FR2655185A1 - Safety switch apparatus operating by insertion and extraction of a key - Google Patents

Abstract

A key (3), fixed to a door of an electrical cabinet, penetrates in the passageway (46) of a safety switch when the door is moved to its closure position, and is extracted from the passageway when the door leaves its closure position. The movement of penetration and of extraction of the key is converted into a movement of rotation of a cam (15) which pushes moving contacts (7a, 7b) into an opening position in the absence of the key, and allows a return spring (11) to bring back the contacts into closure position when the key enters into the passageway. Use for reducing the bulk of the movement conversion mechanism, and for enhancing the tamper-proof qualities.

Description

 The present invention relates to a safety switch device composed of a switch and an operating key, operating by insertion and extraction of the key relative to the switch.

 Such an apparatus can be used in particular in an electrical installation when it is desired that the opening of a door giving access to the installation causes the opening of the corresponding electrical circuit in order, for example, to be able to safely carry out maintenance work on the installation.

 In general, the switch is fixed to the frame of the installation to be protected or to a cabinet containing it, while the key is fixed to the cabinet door. When the door is opened, the key comes out of the switch, and thus opens the system voltage contacts, located in the switch. As soon as the door is closed, the key is reinserted in the switch and the aforementioned contacts are therefore closed.

 Known devices have the disadvantage of being provided with a flat key and of being able to be easily manipulated by conventional tools such as screwdrivers, hooks and other utensils available in workshops. They are also voluminous and of complex realization.

 The object of the invention is thus to propose a safety switch device with an operating key which does not have these drawbacks, and which in particular is reliable and not bulky.

 According to the invention, the safety switch device, comprising a switch and an operating key, the switch comprising a passage in which the key can slide in an insertion and extraction movement by acting on a rotary actuator for close respectively and open the contacts of an electrical circuit, the sliding of the key in the corridor being transformed into a rotational movement of the rotary actuator which is equipped with a cam cooperating with a push button for controlling the switch, is characterized in that the passage is partly defined by a bore of the actuator, which carries the cam on the outside, and in that the key, of substantially circular section, and the actuator have respectively on their outer and inner circumference dese helical ramp means for transforming the movement of insertion and extraction of the key into rotation movement of the actuator.

 The switch device according to the invention can be particularly compact because the space reserved for the key, that is to say the corridor, instead of adding to that necessary for the actuator, extends to the inside the actuator.

 The key has a special aspect which discourages attempts to operate the switch with a tool or other instrument. And in addition, it is indeed difficult to find an instrument which can be inserted into the actuator and have grip on it to drive it in rotation.

 Other particularities and advantages of the invention will emerge from the description below, relating to various nonlimiting examples.

To the accompanying drawings
- Figure 1 is a diagram in horizontal section showing a cabinet equipped with a safety switch device according to the invention;
- Figure 2 is an elevational and sectional view of a switch device according to the invention when the key is out of the housing
- Figure 3 is a section along III-III of Figure 2
- Figures 4 and 5 are views similar to Figure 2 but showing respectively the key being introduced and the key fully inserted in the switch;
- Figure 6 is a sectional view along VI-VI of Figure 5
- Figure 7 is a sectional view of the device along the plane VII-VII of Figure 2, in the unlocked actuator state, key engaged at the top of the figure, and locked actuator and key absent at the bottom of the figure
- Figure 8 is a schematic view of the actuator and the key in section along the plane VIII
VIII of figure 5
- Figure 9 is a front view of the switch, with half-section along the plane IX-IX of Figure 2, the key being absent at the bottom of the figure and engaged at the top of the figure
- Figure 10 is a partial schematic view, in axial section, of a second embodiment of the invention, the locking means being in the unlocked position at the top of the figure and locked at the bottom of the figure
- Figure 11 is a section along XI-XI of Figure 10, the key not being shown in the lower half of the figure
- Figure 12 is a view similar to Figure 2 but relating to a third embodiment of the invention;
- Figure 13 is a section along XIII-XIII of Figure 12
- Figure 14 is a perspective view of the actuator of Figures 12 and 13; and
- Figure 15 is a sectional view along XV-XV of Figure 12.

 In the example shown in Figure 1, the safety switch device according to the invention comprises a switch 1 fixed to a body 40 of an electrical cabinet, and a key 3 fixed by its support 3a to a door or cover 42 articulated to the body 40 along an axis 44. The housing 1 and the key 3 are arranged at a distance from the axis 44. The key 3 is oriented towards the outside of the cover 42, that is to say towards the inside of the body 40 when the cover 42 is in the closed position or close to it.

 From the half-open position shown in FIG. 1, the cover 42 can pivot in the direction of the arrow F to a closed position in which the key 3 is engaged in a passage 46 of the switch 1.

 The key 3 is prevented from turning around its longitudinal axis X1X'1 relative to the support 3a and more generally relative to the door 42.

In what follows, it will be assumed that the key 3 is completely immobilized relative to the door 42, and that the distance between the key 3 and the axis 44 is sufficiently large relative to the length of the key 3 so that the movement of the key 3 between the beginning and the end of its penetration in the corridor 46 at the end of the closing movement of the door 42 can be considered to be substantially rectilinear, as shown in FIG. 2 by the co-linearity of the axes XX 'from corridor 46 and
X1X'1 of key 3.

 The switch 1 comprises a contactor 5 comprising a contact-carrying rod 6 and a push-button 9 movable together in a direction YY 'perpendicular to the axis XX' of the passage 46. The contact-carrying rod 6 carries two contact bridges 7a, 7b. The contact-carrying rod 6 is returned by a return spring 11 to a position in which the contact bridges 7a and 7b electrically bring together a pair of contacts 8a and respectively a pair of contacts 8b. The action of the spring 11 is directed towards the corridor 46.

 The pusher 9, which acts on the contact carrier rod 6 at its end opposite the spring 11, is subjected to the action of a cam 15 which selectively pushes the pusher 9 - rod 6 assembly, against the action of the return spring 11, in a position where the contact bridges 7a and 7b are spaced from the fixed contacts 8a and 8b respectively.

 In the example shown, the housing 100 of the switch comprises a lower housing containing the contacts 8a and 8b, the contact bridges 7a and 7b and the contact-carrying rod 6 as well as the spring 11, and a housing 1b containing in particular the pusher 9, the cam 15 and the passage 46. The box lb can be fixed in various angular orientations around the axis YY 'relative to the box la to increase the possibilities of installation for example in the cabinet body 40 of FIG. 1, in which the housing 1a can be fixed against the bottom of a relatively flat cabinet or against a side wall of a deeper cabinet, the entrance opening of the passage 46 always being oriented towards the plane of joint between body 40 and door 42.

As shown in Figures 2 to 6, the cam 15 is formed at the periphery of a rotary actuator 13 in the form of a socket, which is supported in rotation along the axis
XX 'and whose internal bore 13a defines part of the passage 46 for the key. The key 3 has a cylindrical shape (Figures 6 and 8) whose diameter is little less than the diameter of the bore 13a of the actuator 13.

 The actuator 13, for its rotational support, is held captive between profiled ribs lc of two upper half-housings lba and lbb (Figure 2), which together constitute the upper housing lb.

 The actuator 13 and the key 3 are provided with means capable of cooperating to transform the sliding movement of the key, without rotation about the axis X1X'1, in the corridor 46 into a movement of rotation of the actuator 13 around the XX 'axis without sliding along the XX' axis.

 These means are of the helical ramp type. For this purpose, the key 3 comprises two helical grooves 19 which are diametrically opposite in each plane perpendicular to the axis X1X'1. Each helical groove 19 is defined between two helical ramps 19a and 19b.

Furthermore, the actuator 13 carries on its inner periphery, that is to say on the wall defining the passage 46, two diametrically opposed lugs 17 in the form of a parallelogram, having two opposite faces 17a parallel to the axis XX 'and two opposite oblique faces 17b having a slope corresponding to the slope of the ramps 19a and 19b respectively of a respective one of the grooves 19.

 As shown in FIG. 2, when the key is outside the switch 1, the actuator 13 has around its axis XX ′ an angular position such that the cam 15 maintains the contact-carrying rod 6 in the position of opening of contacts 8a and 8b against the return force provided by the spring 11.

 As shown in FIG. 4, when the key 3 enters the passage 46, after a certain initial stroke during which the actuator 13 is unlocked (this will be described later), each lug 17 engages in an attack groove 19c formed parallel to the axis in the side wall of the key 3 between the free end of the key 3 and a front end of each of the helical grooves 19. During this engagement movement, the faces 17a parallel to the axis of the lug 17 slide against the adjacent faces of the attack groove l9c.

 In the course of the key 3 penetration movement, each lug 17 slides between the helical ramps 19a and 19b. It is then the oblique faces 17b of the lug 17 which are in contact with the ramps 19a and 19b. The ramp 19a, which is turned towards the inside of the switch housing, is active during the penetration of the key 3 to have on the lug 17a a cam effect causing the actuator 13 to rotate in a direction such that the cam 15 allows the push-button 9 and the contact-carrying rod 6 to be raised under the action of the return spring 11, until the situation shown in FIGS. 5 and 6, in which the contact bridges 7a and 7b bring together the contacts 8a and 8b respectively.

At its end which is close to the lug 17 when the key is fully engaged in the switch (Figure 5), each helical groove 19 is connected to an axial groove 19d which extends in the direction opposite to the free end of the key and which constitutes for the pin 17 corresponding an axial slide in which the pin 17 engages during a final phase of penetration of the key. On either side of each helical groove 19, the leading groove 19c and the axial groove 19d are in a well-defined angular position relative to each other around the axis
X1X'1 of the key. In the example shown, they are 900 from each other around the axis X1X'1. Thus, the angular travel of the actuator 13 during penetration of the key or during its extraction is exactly equal to the angular difference between the leading groove 19c and the axial groove 19d, that is to say 900 in the example. For this, the penetration stroke of the key does not need to be adjusted with precision, the only condition being that this stroke is sufficient for the lugs 17 to at least begin to engage in the axial grooves 19d when the door to which the key 3 is fixed is in the closed position.

 When the key is extracted, it is the helical ramps 19b of the grooves 19 which bear on the corresponding oblique faces 17b of the pins 17 to transform the sliding movement of the key 3 into a rotation movement of the actuator 13 in the direction bringing the cam 15 from the angular position shown in FIG. 5 to that shown in FIGS. 2 and 3. There is therefore mechanical drive of the actuator 13 by the key 3 during the extraction of the key, and in turn, the actuator pushes mechanically, that is to say by action of the cam 15 on the pusher 9 against the return spring, the contact bridges 7a and 7b in the open position. the switching device in the process of being described, as well as those of the examples which follow, have a "positive on opening" operation since the movement of extraction of the key 3 is transmitted entirely mechanically to the contact bridges 7a and 7b. This increases the reliability with which the supply to the installation to be protected is cut off when the installation is accessed for maintenance or repair. On the contrary, during penetration of the key, the actuator 13 only allows the return spring 11 to apply the contact bridges 7a and 7b against the fixed contacts 8a and 8b.

 We will now describe the locking means which, in the absence of the key 3, lock the actuator 13 in the position shown in FIG. 2, in which the contact bridges 7a and 7b are pushed back into the open position at against the action of the spring 11.

 The locking means comprise two half-shells 21 which define between them an inlet 46a of the passage 46. For this purpose, each half-shell 21 has on its face turned towards the other half-shell a segment of concave truncated cone 21a , flared towards the outside of the housing, and connected on the inside of the housing to a concave cylinder segment 21b. These segments extend over less than 1800. Each segment 21 carries on its three other faces a peripheral groove 51 in which is engaged an annular book 52 defining a rectangular opening 53 in the front wall of the upper case 1b.

 As shown in FIG. 9, this engagement of the lip 52 in the groove 51 axially immobilizes the half-shells 21 but allows them to slide in a direction Y1 perpendicular to the axis XX ', between a locking position shown at the bottom of FIG. 9, and in FIG. 2, in which the half-shells 21 are pressed against each other under the action of return springs 54, and an unlocking position, represented at the top of FIG. 9 and in Figures 5 and 6, in which the half-shells 21 are spaced from one another in the direction Y1.

 In the locked position, the recesses 1b, which have substantially the same radius as the key 3, together define a passage whose cross section is smaller than that of the key 3. In the unlocked position, the two cylindrical recesses 21b are substantially on the same ideal cylinder of axis XX 'corresponding to the space occupied by the key 3 in the corridor 46.

 Thus, when the key 3 is absent, the half-shells 21 are returned to the locking position by the springs 54. When the key 3 begins to penetrate into the switch 1, its frustoconical end 3c cooperates with the frustoconical recesses 21a of the half-shells 21 for move the half shells 21 apart from one another and thus push them back into the unlocked position against the action of the springs 54.

 As shown in FIG. 7, each half-shell 21 carries on its side facing the actuator 13 a dog clutch 23 which, in the locking position of the half-shell covers a tooth 27 formed on the outer periphery of the actuator 13 and which is located circumferentially in regad of the dog clutch 23 when the actuator 13 is in its well-determined angular position corresponding to the absence of the key. When the half-shells 21 are in the unlocking position (upper part of FIG. 7) the dog 23 of each half-shell is spread radially outwards so as to release the corresponding tooth 27. When the half-shells 21 are in the locked position, the dogs 23 thus prevent the actuator 13 from rotating in one or the other direction around the axis XX ', and they allow this rotation when the half-shells 21 are in the unlocked position . During their radial movement between the locking and unlocking positions, the dogs 23 each slide between two support ribs 57 which reinforce the immobilization of the half-shells 21 with respect to any rotation about the axis XX ', and more particularly the immobilization in rotation of the dogs themselves which are liable to be highly stressed in the event of a fraudulent attempt to cause the rotation of the actuator 13 with an instrument other than the key 3.

 The presence of this locking device makes it much more difficult any fraudulent attempt to cause rotation of the actuator 13 in the absence of the key because the person making such an attempt should manage to simultaneously separate the two half-shells 21 while exercising a rotation action on the lugs 17.

 In addition, the locking means 21 have the function of immobilizing the actuator 13 with respect to mechanical disturbances such as vibrations which, in the absence of the key 3, would be liable to rotate the actuator 13 with the using spring 11. This could lead to a very dangerous re-establishment of the power supply during a maintenance operation.

 It is understood by examining FIG. 3 that the key 3 must perform a certain stroke between the moment when the half-shells 21 are pushed back into the unlocked position and the moment when the lugs 17 are captured by the attack grooves 19c. If during this intermediate stroke vibrations or other mechanical disturbances caused a spontaneous rotation of the actuator 13, the lugs 17 would no longer be facing the attack grooves 19c when the key reaches the lugs 17 and the following movement of penetration does not could not take place. To avoid this, the top of the cam 15 has a recess 58 in the form of a concave spherical cap in which the pusher 9 snaps under the action of the spring 11 when the key is absent.

This provides the actuator 13 with the necessary stabilization during the short period of time between the spacing of the half-shells 21 and the capture of the lugs 17 by the attack grooves 19c.

 For its proper functioning, the actuator 13 must be immobilized with respect to any translation along the axis XX '. For this, the actuator 13 is interposed, without play other than that necessary for its free rotation, between the two half-shells 21, themselves prevented from moving along the axis XX 'as explained above, and a shoulder 55 formed in a rear wall of the upper housing 1b, opposite the entry 46a of the passage 46.

 The example of Figures 10 and 11 will only be described with regard to its differences from the previous one.

In this example, the inlet 46a of the passage 46 is defined by the front wall 59 of the upper housing 1b, and the actuator 13 extends to this wall 59. The locking members are constituted by plungers 28 mounted from sliding way in a radial direction relative to the axis XX 'in diametrically opposite openings 31 made in the wall of the actuator 13 in the vicinity of the front wall 59. The locking members 28 are therefore integral with the actuator 13 to with regard to rotations around the axis
XX '. A peripheral elastic member, such as a caliper leaf spring 61, simultaneously surrounds the two locking members 28 and returns them to a projecting position, shown at the bottom of Figures 10 and 11 in which a ramp 28a of each actuator 28 makes projection in the corridor 46 defined by the actuator 13.

When the key 3 engages in the corridor 46, its frustoconical end 3a cooperates with the ramps 28a to push the locking members 28 into an unlocked position (top of FIG. 10) against the action of the elastic strap 61.

 At its end directed towards the wall 59, the actuator 13 is rotatably supported in a collar 62 having two diametrically opposite notches 63.

When the actuator 13 is in its angular position corresponding to the absence of the key, a dog 64 carried by each locking member 28 is opposite the notches 63. When the locking member 28 is in the locking position, the dog 64 is engaged in the notch 63 so as to immobilize the actuator 13 with respect to the rotations around the axis XX '. On the contrary, when the locking member 28 is in the unlocking position, as shown at the top of FIGS. 10 and 11, the dog clutch 64 is released from the notch 63 and allows the actuator 13 to rotate around the axis. XX '. Is shown at the top of Figure 11 the dog 64 having rotated about 450 about the axis XX 'relative to the corresponding notch 63.

 In this embodiment, the pins 17 are placed substantially in the same plane perpendicular to the axis XX 'as the locking members 28, the unlocking taking place while the pins 17 are already captured by the attack grooves 19c . Under these conditions, there is no longer any risk of parasitic rotation of the actuator 13 between the moment when the unlocking has been carried out and the moment when the pins are captured by the grooves of the key, since these two moments are substantially confused. In addition, the stroke that the key must make in the actuator corridor is reduced, which makes it possible to mount the key 3 with a shorter radius of gyration around the pivot axis 44 (FIG. 1) of the door pivoting. without this entailing a risk of jamming the key in the corridor 46.

 The example of FIGS. 12 to 15 will only be described with regard to its differences from that of FIG. 2.

 The key 3 comprises four helical grooves 19, leading grooves 19c and axial grooves 19d, and the actuator 13 comprises in lane 46 four pins 17 distributed at angular intervals of 900 around the axis XX '. This increase in the number of ribs and lugs has two advantages. It increases the safety of actuation because the shearing forces on each lug are less significant and the risk of rupture of a lug is therefore less. In the event of a lug breaking, there are still three left to ensure transmission.

On the other hand, this embodiment makes it possible to mount the key in four different orientations around its axis relative to the switch 1. This can solve certain cases of mounting in particularly limited spaces.

 The locking members 71 are two diametrically opposite relative to the axis XX 'and slidably mounted in a direction Z (Figure 13) which is oblique, and more particularly at 450 relative to the direction YY' of sliding of the pusher 9. The locking members 71 are slidably mounted in housings defined between them by the two half-housings îba and îbb behind the front wall 59 of the upper housing 1b.

 Return springs 72 mounted in the aforementioned housings urge the locking members 71 towards the locking position shown at the bottom of FIGS. 13 and 15, and in FIG. 12, in which a ramp 71a of the locking members 71 projects into the entry 46a of the corridor 46 defined by the box lb.

When the key 3 enters the corridor 46, its tapered end 3a acts on the slopes 71a to push the locking members 71, against the return springs 72, in an unlocked position shown at the top of Figures 13 and 15 .

 On their side facing the actuator 13, the locking members carry a dog clutch 73, which, when the actuator 13 is in its angular position corresponding to the absence of the key, is located opposite a corresponding notch 74 formed in a front flange 76 of the actuator 13. The flange 76 is housed in an annular recess 77 of the housing 1b, which communicates with the housings reserved for the locking members 71. When the locking members 71 are in the locking position, the dogs 73 are engaged in the notches 74. On the contrary, when the locking members 71 are in the unlocked position, the dogs 73 are spaced radially outward from the notches 74 and allow the actuator 13 to rotate freely on a angular travel of 90 delimited by two stops 78 and 79 also formed on the flange 76.

 As shown in FIG. 14, the cam 15 has a spherical recess 58 in which the pusher 9 is engaged when the cam 15 is in the position corresponding to the opening of the contacts. In addition, another recess 81 is provided in the base of the cam 15, to allow the pusher 9 to snap into the position corresponding to the closing of the contacts.

 Of course, the invention is not limited to the examples described and shown.

 One could for example provide that the attack grooves such as 19c have a length sufficient for the locking members to be located downstream of the lugs in the embodiment of FIGS. 10 and 11.

 It could also be provided that the projections such as the pins are carried by the key and that the helical ramps are formed on the wall of the bore of the rotary actuator.

Claims (16)

 1. Safety switch device comprising a switch (1) and an operating key (3), the switch comprising a passage (46) in which the key (3) can slide in a movement of introduction and extraction in acting on a rotary actuator (13) to close and respectively open the contacts (8a, 8b) of an electrical circuit, the sliding of the key (3) in the passage (46) being transformed into a movement of rotation of the rotary actuator (13) which is equipped with a cam (25) cooperating with a control button (9) of the switch, characterized in that the passage (46) is at least partially defined by a bore (13a) of the actuator (13), which externally carries the cam (15), and in that the key (3), of substantially circular section, and the actuator (13) have respectively on their outer and inner periphery means to helical ramp (17, 19) for transforming the key insertion and extraction movement (3) in rotational movement of the actuator (13).  2. Switching device according to claim 1, characterized in that the means with a helical ramp (17, 19) comprise at least one ramp (19a) active in the direction of introduction of the key (3) and a ramp (19b ) active in the direction of key extraction.  3. Switching device according to claim 2, characterized in that the means with a helical ramp comprise a lug (17) capable of engaging between the two ramps (19a, 19b) each active in one of the directions.  4. Switching device according to claim 3, characterized in that the lug (17) has a parallelogram shape with two opposite faces (17a) parallel to the direction of movement of the key (XX ') to slide in a groove axial attack (19c) of the two ramps (19a, 19b) and two opposite oblique faces (17b) each intended to be applied to one of the two ramps (19a, 19bu,  5. Apparatus according to claim 1, characterized in that the helical ramp means comprise at least one helical ramp (19a, 19b) carried by the key (3) and a projection (17) formed inside the actuator (13) to cooperate with this ramp.  6. Switching device according to claim 1, characterized in that the means with a helical ramp comprise at least one ramp (19b) active in the direction of extraction of the key (3) corresponding to the opening of the switch, which is forced opening by the cam (15) and elastic return to the closed position.  7. Switching device according to one of claims 1 to 6, characterized in that it further comprises, in the housing, a locking device (21, 28, 71) placed to be actuated by the key (3) before the rotation of the actuator (13) during the introduction of the key, this locking device comprising at least one radially movable member (21, 28, 71) between a locking position to which it is resiliently biased and in which it projects into the path of the key (3) while the actuator (13) is locked in an open position of the switch, and an unlocked position in which it is pushed back by the key (3) when this is at least partially introduced into the housing (1) and in which the actuator (13) is free to rotate under the action of the key (3).  8. Apparatus according to claim 7, characterized in that the radially displaceable member is a latch (21, 23, 71) selectively coupling the actuator (13) with a housing (lb) of the switch.  9, Apparatus according to one of claims 7 or 8, characterized in that in the unlocked position, the radially movable member (71) is located between two stops (78, 79) limiting the angular travel of the actuator ( 13).  10. Apparatus according to one of claims 7 to 9, characterized in that the radially displaceable member (21, 71) is integral with the housing with respect to the rotations around the axis (XX ') of rotation of the 'actuator (13).  11. Apparatus according to one of claims 7 to 9, characterized in that the radially displaceable member (28) is integral with the actuator (13) with respect to the rotations around the axis (XX ') of actuator rotation.  12. Apparatus according to one of claims 7 to 11, characterized in that it comprises at least two radially displaceable members (23, 28, 71) diametrically opposite, regularly distributed around the axis of rotation of the actuator ( 13).  13. Switching device according to claim 12, characterized in that the radially displaceable members (71) are displaceable in oblique directions (Z) relative to the direction (YY ') of sliding of the control pusher (9).  14. Switching device according to one of claims 7 to 13, characterized in that the key (3) and the actuator (13) comprise means (17, 19c) which interact to allow relative axial sliding without rotation between the key and the actuator during the movement of the locking members (28) between their locked and unlocked position under the action of the key.  15. Switching device according to one of claims 1 to 13, characterized in that the cam (15) and the control pusher (9) have complementary conformations (58) producing a locking by force threshold with respect rotation of the actuator (13) about its axis (XX ') when the cam (15) is in the position corresponding to the absence of the key (3) in the switch (1).  16. Switching device according to claim 1, characterized in that under the means of a helical ramp, the key (3) and the actuator (13) comprise at least one helical ramp (19a, 19b) and l 'other at least one projection (17) which move along this ramp when the key (3) slides in the corridor (46), characterized in that one end of the ramp which is close to the projection ( 17) when the key is fully engaged in the corridor (46) the ramp is connected to an axial slide (19d) for the projection (17).