Rotary switch assembly

TECHNICAL FIELD

The present disclosure relates to the field of rotary devices, e.g. rotary electrical switches, in particular indexing mechanisms for blocking or releasing rotation of a spindle.

More in particular, the present disclosure relates to an indexing system for a rotary switch, comprising a housing, a driving part and a driven part, both being coupled to the housing for rotation with respect to the housing and each other about an axis of rotation, the driving part being configured to provide a force to the driven part for said rotation about the axis, wherein the housing and the driven part comprise

cooperating indexing means defining one or more relative angular positions . BACKGROUND

Indexing systems for rotary switches as referred to above are known in the art. E.g. GB 1 159 729, DE 1 058 123 and WO 2009/121744, describe indexing systems wherein the driven part comprises a generally C-shaped locking spring extending radial about the axis of rotation and having axially upturned tips, and the housing comprises a lid with indexing protrusions extending axial towards the locking spring. The driven part and the housing cooperate such that the indexing protrusions are receivable between and engaged by the upturned ends of the locking spring, thus blocking relative rotation and defining discrete rotary positions. The driving part comprises axially extending portions to depress, in a particular angular position with respect to the driven part, an upturned tip of the locking spring past the indexing protrusion, therewith freeing the driven part for rotation in the corresponding direction of rotation. A spring is arranged between the driving and driven parts to impart a rotation force on the driven part by operation of the driving part. Such systems have proven robust and reliable. However, the locking spring tends to exert both axial and tangential forces on (the indexing protrusions of) the lid, requiring a bulky housing, a strong lid and tight design tolerances for accurate operation.

DE 2 145 579 discloses a switching mechanism comprising a housing with a cap (1) and a lid (5) between which a switching spindle (2), a latching rotor (3) and a switching coil spring (4) are arranged. The cap comprises protrusions (la) and the latching rotor comprises corresponding recesses (3a) to define indexing positions. The spring urges the switching spindle and the latching rotor together, and it urges the latching rotor against the cap. By rotation of the switching spindle the switching spring is tightened and (recesses of) the rotor (are) is lifted off (protrusions of) the cap against the axial force of the spring, so that the rotor may rotate to a subsequent indexing position.

Due to the axial spring action, the mechanism obviates tight axial design tolerances. However, all forces on the housing are in axial direction requiring a strong housing, and during rotation the rotor is pressed against the cap causing friction. The mechanism therefore requires a relatively large volume and it is prone to wear and loss of reliability.

GB 1 342 392 and GB 1 485 002 disclose another switching mechanism of the abovementioned kind, wherein the driven part comprises spring-loaded indexing bolts extending radial from a main body to engage radial indexing recesses in a circumferential wall of the housing. The driving part comprises pegs to force, during operation, the indexing bolts radially inward into the main body of the driven part against the spring- loading force to free the driven part for rotation.

Such systems comprise a large number of parts and thus may become delicate when reducing their size. They also may be costly .

An improved indexing system is therefore desired. SUMMARY

An indexing system of the above-mentioned kind is herewith provided, wherein the indexing means comprise at least one first indexing member extending generally tangentially and/or azimuthally with respect to the axis of rotation and being at least partly reversibly movable between a first and a second radial position, wherein in the first radial position the indexing means cooperate to block relative rotation of the housing and the driven part about the axis of rotation and in the second position the indexing means allow such relative rotation of the housing and the driven part about the axis of rotation .

Due to the tangential and/or azimuthal arrangement of the first indexing member, rotation may be effectively blocked with a blocking force extending substantially in the direction of the first indexing member. The first indexing member may therefore be of reduced transverse strength, i.e. in radial and/or axial direction. Further, blocking or unblocking rotation by radial displacement of the first indexing member allows reducing construction height and/or tolerances in axial

direction .

The first indexing member may comprise a resilient element. Thus a restoring force towards a predetermined position may be provided, e.g. towards the first radial position for security by ensuring blocking of rotation.

The driven part may comprise the first indexing member. This facilitates manufacturing, e.g. by moulding techniques.

The cooperating indexing means may comprise two or more, possibly substantially symmetric, first indexing members. Thus, rotation in opposite directions may be blocked. Plural first indexing members may be operative contemporary in one relative position of the housing, e.g. being operative on (at least a portion of) one second indexing member received between the first indexing members.

At least one first indexing member may comprise a latching structure cooperating with at least a portion of a second indexing member facilitating relative rotation in a first direction and blocking rotation in a second, opposite direction about the axis of rotation. Thus in the first direction the first indexing member may snap behind (the portion of) the second indexing member without further external control. This may facilitate locking the housing and the driven part to a particular indexing position.

The housing and the driven part may also comprise further cooperating indexing means, which may be substantially rigid, e.g. cooperating protrusions and recesses fixed to the respective parts, blocking rotation beyond a predetermined relative rotary position. In such case the first and second indexing members need not provide a stopping force and need not be dimensioned to absorb significant forces developed by inertia of masses coupled to the driven part, e.g. a large number of switching contacts. Relatively delicate and/or small indexing members may thus be provided, compared with the structures presently employed. In particular when switching one or more relatively heavy parts connected to the driven part, the further indexing means may absorb rotational momentum and provide stopping power, whereas the first and second indexing members provide definition of a relative position, for which no

permanent engagement or force is needed.

In an embodiment without permanent engagement or force for definition of the indexing position, one or more first and/or second indexing members may comprise a polymeric, e.g. plastics, portion since creep of such portion is prevented.

The driving part and/or the driven part may comprise further control portions for engaging and radially moving at least part of the first indexing member from the first radial position to the second radial position in a predetermined relative rotary position with respect to the driven part. Thus, blocking or allowing relative rotation of the driven part and the housing is determined by the relative rotation of the driving and driven parts, providing control over the rotation of the driven part. The control portions may extend axially to reduce radial construction volume.

In an embodiment with such further control portions, the first indexing member may comprise blocking stops and axially extending control portions, and wherein preferably the blocking stops comprise a bevelled and/or chamfered edge opposite the axially extending control portions. The axially extending control portions facilitate direct control of the first indexing member, in particular when the control portions are arranged at or near a portion configured to engage the second indexing member. The bevelled and/or chamfered edge allows accounting for torsion of the first indexing member when subject to a force on the control portions, improving control over operation of the (un) blocking .

The driving part and the driven part may be coupled with a resilient element providing a spring force upon relative rotation of the driving part and the driven part. In this way the driven part may be spring loaded by rotary action of the driving part.

The resilient element may be configured to engage the driving part and the driven part at substantially the same axial position with respect to the axis of rotation. This prevents relative tilt of the driving and driven parts, facilitating operation and reducing wear.

At least one of the driving part and the driven part may be connected to a spindle part with a snapping or latching connection. This facilitates connecting the respective parts reliably.

The housing may comprise a cover, e.g. a lid, covering the driving part and the driving part is preferably connectable to a spindle part through the cover. The cover protects the driving part and possibly also the driven part. Connecting the driven part and the spindle part through the lid facilitates manufacturing of the indexing system. Further, the driving part and the spindle part may be provided as a lock-and-key assembly.

The cover may be attached or at least attachable to the housing from one direction, the housing being attachable to an apparatus to be operated by the indexing system from an opposite direction. This way opening of the cover may be prevented when the indexing system is attached to the apparatus. Further, separately optimised attachment provisions may be provided. The indexing system may be stackable from one side for operably assembling the indexing system. This facilitates manufacturing .

An apparatus may be manufactured or modified by providing it with a system as described to reduce its size.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-described aspects will hereafter be more explained with further details and benefits with reference to the drawings showing an embodiment of the invention by way of example .

Fig. 1 is an explosion view of an embodiment of an indexing system;

Figs. 2A and 2B are perspective views of a base part of the indexing system of Fig. 1;

Figs. 3A and 3B are perspective views of a lid of the indexing system of Fig. 1;

Figs. 4 and 5 are perspective top and bottom views, respectively of an alternative housing of an indexing system.

Fig. 6 is a perspective top view of a spindle part, a driving part, a spring and a driven part of the indexing system of Fig. 1;

Fig. 7 is a perspective bottom view of the driving part, the spring and the driven part of Figs. 1 and 6;

Figs. 8A-8D indicate operation of the system Figs. 9A-9D are different perspective views of a different driven part, with Fig 9B showing detail B indicated in Fig. 9A;

Figs. 10 and 11 are perspective top views of different embodiments of a base part;

Fig. 12 is a perspective bottom view of a base part; Fig. 13 is a perspective bottom view of a modular base part .

DETAILED DESCRIPTION OF EMBODIMENTS

It is noted that the drawings are schematic, not necessarily to scale and that details that are not required for understanding the present invention may have been omitted. Further, like elements carry like numbers, where useful provided with an alphabetic suffix and/or primed.

Fig. 1 shows an indexing system 1, comprising a base 3, a driven part or "blocker" 5, a torsion spring 7, a driving part or "driver" 9, a spindle part 11 and a lid 13 mated to the base 3. The base 3 and the lid 13 form a housing. Figs. 2Ά-3Β show the base 3 and lid 13 in more detail and Figs. 4 and 5 show an alternative housing comprising a base 3' and a lid 13'. Figs. 6 and 7 show the blocker 5 and the driver 9 in more detail.

Referring to Figs. 1-3B, the base 3 and the lid 13 can be fitted together to form a housing defining a substantially enclosed cavity accommodating the blocker 5, the spring 7, the driver 9 and a portion of the spindle part 11, such that they are coupled to the housing 3; 13 for rotation with respect to the housing 1;13 about an axis of rotation A, here passing through the centres of the respective parts 3-13 when assembled. The blocker 5 and the driver 9 are coupled to for rotation with respect to each other about the axis of rotation A, wherein the blocker 5 and the driver 9 are coupled with the spring 7 (for details see below) .

In the following, and referring to the coordinate system shown in Fig. 1 all references to directions "axial", "radial", "tangential" or "azimuthal", "angle of rotation", etc. relate to the axis of rotation A, as indicated with A, R, T and <j), respectively in the coordinate system and terms "upward",

"downward", "below", "above", etc. relate to the embodiments as oriented in the drawings, unless otherwise specified.

Referring to Figs. 2A and 2B, the base 3 comprises a generally circular cavity 17 defined by an outer wall 19 and a bottom wall 21 having a central opening 23 for passing a spindle portion to connect the indexing system 1 with an apparatus to be switched, e.g. a rotary electrical switch of the type of WO

2009/121744. The base 3 comprises optional connection structures for connection to the apparatus to be switched and/or other objects such as mounting panels. E.g., here it has the form of a generally rectangular flange .25 comprising snapping latches 27 and other structures for connection to a housing module as described in WO 2009/121744, and further openings 29. Figs. 4 and 5 show a base 3' for forming a substantially identical indexing system but provided with alternative connection

structures in the form of a generally rectangular flange 25' comprising snapping windows 27', openings 29, and other

structures for connection to a housing module as described in WO 2009/121744 from an opposite side compared to the base 3 of Figs. 1-2B. Further attachment structures, here in the form of holes 30, are provided for fixing the base 3 and the lid 13 together .

The interior surface of the outer wall 19 describes a generally circular shape centred about the axis A. An optional rim 31 extends within the cavity 17 around the outer wall 19. Extending axially upward from the rim 31 and radially inward from the outer wall 19 are protrusions 33 flanked by optional radial recesses 35 into the outer wall 19. Here, groups of protrusions 33 and recesses 35 are arranged at mutual angles of about 90 degrees around the axis A. The protrusions 33 may extend in axial direction less than the full height of the cavity 17 of the housing, here about half the height of the outer wall 19 from the bottom wall 21.

On the bottom wall 21 are blocking surfaces 37A and 37B protruding upward in axial direction, here being formed by a protrusion 39 protruding upward in axial direction from the bottom wall 21 having a circumference around the axis A with varying radius.

The outer wall 19 is surrounded by an optional circumferential wall 41, here comprising keys, such as the shown relatively high portions 43 and relatively low portions 45.

Figs. 4 and 5 show a base 3' for forming another housing of the indexing system, being generally identical to the base 3 in that respect. As a difference, the base 3' comprises alternative connection structures in the form of a generally rectangular flange 25' comprising snapping windows 27', openings 29, and other structures for connection to a housing module as described in WO 2009/121744 from an opposite side compared to the base 3 of Figs. 1-2B.

Referring to Figs. 3A and 3B, the lid 13 comprises a cover portion 47 with an central through hole 49 about the axis A, and a rim 51 along at least part of the cover portion 47. The rim 51 here comprises optional keys such as the shown relatively low portions 53 and relatively high portions 55 mated to the keys 43, 45 of the base 3. Further, the lid 13 comprises

optional structures for connection to the apparatus to be switched and/or other objects such as mounting panels, here in the form of openings 57. Connection structures 59 for fixation to the base 3 are provided in the form of mounting blocks for receiving screws (not shown) passing upward through openings 30 of the base 3, which may extend through an apparatus connected to the system or be rendered inaccessible by it. The connection structures 59 here have shapes mated to the corresponding portions of the base 3, here being substantially rectangular. Instead, the base 3 and lid 13 may be attached by latching, welding, gluing, riveting or other fixing techniques.

The shown central through hole 49 of the lid 3 has a central substantially circular portion 61 and two radially extending "ears" 63. Thus, the central through hole 49 is formed for passing the spindle part 11 from opposite directions, as set out below. Further, the lid 3 comprises optional protrusions 64 and plural optional fortification structures, here in form of substantially radially extending ribs 65.

Figs. 4 and 5 show a lid 13' for forming another housing of the indexing system, being generally identical to the lid 13 in that respect. Different, the lid 13' comprises a substantially circular central hole 49' and a connection stub 66 with a non-circular circumference for non-rotary attachment in a correspondingly shaped opening in another object, e.g. a panel of a device. The connection stub 66 may comprise a screw thread for a screwed connection to a panel or other attachment means, e.g. snap latches.

Figs. 6 and 7 show the blocker 5, the associated driver 9 and the spring 7 of Fig. 1 in top and bottom views,

respectively. Fig 6 further shows the spindle part 11 of Fig. 1.

The spindle part 11 is elongated in axial direction and comprises a connector 67 for connection to a handle, here having a non-circular circumference, an optional waist 69 for receiving a clamping ring, and a connector 71 for connection to the driver 9. The driver connector 71 also has a non-circular

circumference, here comprising radial recesses 73 extending along the axial direction of the extension of the spindle part 11 and two radially extending protrusions 75. Further, the driver connector 71 comprises a latch 77.

The indicated spring 7 is a helical coil of resilient material, e.g. metal wire, of which the opposite ends 78A, 78B are formed to extend, in relaxed state, substantially at equal axial height.

The driver 9 comprises a radially extending structure, here a disc 79, from which a first protrusion 81 and a second protrusion 83 extend downward in axial direction, here also extending along the circumference of the disc 79 in azimuthal direction. At or near its top the disc 79 comprises optional circumferential recesses 84. The driver 9 is provided with a connector 85 for connection with the connector 71 of the spindle part 11. The connector 85 extends axially downward from the disc 79 and provides a hole 87 with a circumferential shape matching that of the connector 71 and a latch receiving window 89 for receiving the connector 71 of the spindle part 11 and attaching both parts 9, 11 by snap action of the latch 77 to the window 89.

Between the first and second protrusions 81, 83 and the connector 85 the driver 9 has a circumferential cavity 91.

The first protrusion 81 of the driver 9 is formed as a skirt portion and provides two axially and radially extending control portions 93A, 93B on generally radially opposite sides of the driver 9. The control portions 93A, 93B, have guiding surfaces 95A, 95B extending at an inwardly obtuse angle to the azimuthal direction. Here, the skirt portion has a first portion 97, here proximate the disc 79, of substantial constant inner radius and a second portion 99, here distal from the disc 79 with larger radius and defining the control portions 93A, 93B and guiding surfaces 95A, 95B. The first protrusion 81 further comprises optional circumferential slots 101A, 101B opposite each other.

The second protrusion 83 comprises opposite axially extending side faces 103A, 103B for engaging, at least in operation, one of the opposite ends 78A, 78B of the spring 7 (see below) .

The blocker 5 comprises a radially extending structure, here a disc 105, from which a first wall 107 and a second wall 109 extend upward in axial direction. The first wall 107

comprises a hollow tubular portion centred about the axis A, providing a cavity 110, and having a first protrusion 111. The second wall 109 extends along part of the circumference of the disc 105 in azimuthal direction and comprises a second

protrusion 113, having opposite axially extending side faces 115A, 115B for engaging, at least in operation, one of the opposite ends 78A, 78B of the spring 7 (see below) . The first and second protrusions 111, 113 extend to substantially the same axial height.

Between the first and second walls 107, 109, the blocker 5 has a circumferential cavity 117.

The blocker 5 comprises cantilevered resilient arms 119A, 119B extending in azimuthal direction from the first wall 109, and being spaced from the disc 105 and here also radially offset from the first wall 109. The arms 119A, 119B of the shown embodiment are mutually symmetric and comprise, at or near their ends, optional outward extending blocking stops 121A, 121B and axially extending control portions 123A, 123B, which are movable in radial direction due to the resiliency of the cantilevered arms 119A, 119B. Upper surfaces 124A, 124B of the arms 119A, 119B extend substantially at one axial height.

At the bottom side, the blocker 5 comprises

substantially radial blocking surfaces 125A and 125B protruding downward in axial direction, here being formed by blocking protrusions 127 protruding downward in axial direction from the disc 105.

Further, at the bottom side, the blocker 5 comprises a connector 129 for connection to a spindle of an apparatus to be operated by the indexing system 1. Here, the connector 129 has a first, circular, cylindrical portion 131 and a second

cylindrical portion 133 that is substantially non-circular, here being rectangular, in particular square. Alternative connectors, e.g. with a non-circular recess as in WO 2009/121744 or configured for fork-and-blade coupling, may be provided as well.

The arms 119A, 119B comprise axial downward protrusions 135A, 135B which extend to substantially the same axial height as the blocking protrusions 127.

For assembly of the indexing system 1, a sub-assembly of the blocker 5, the spring 7 and the driver 9 is made. For this, the spring 7 is arranged in the blocker 5, wherein the helical windings of the spring 7 are received in the cavity 117 of the blocker 5, encircling the inner wall 107. The end 78A of the spring 7 engages the side face 115B of the second protrusion 113 of the blocker 5 and the end 78B of the spring 7 engages the opposite side face 115A. Next, the driver 9 is arranged over the blocker 5, with the downward protruding portion of the connector 85 received in the cavity 110. The diameter of the driver 9 is such that its first and second protrusions 81, 83 envelop the blocker 5 with portions of both inner and outer walls 107, 109 of the blocker 5 and of the spring 7 being received in the cavity 91 of the driver 91. Further, each end 78A, 78B of the spring 7 engages the respective side faces 103A, 103B of the second protrusion 113 of the blocker, wherein the side faces 103A, 103B, 115A, 115B and both spring ends 78A, 78B are at substantially equal axial positions. The spring 7 being

accommodated in the blocker 5 and driver 9 allows reduction of the construction height.

When assembled, relative tilt of the driver 9 and blocker 5 is preferably prevented, such as by cooperating surfaces. Here, the first and second protrusions 111, 113 and the surfaces 124A, 124B of the arms 119A, 119B of the blocker 5, respectively bear against the disc 79 and the second skirt portion 99 of the first protrusion 81, respectively, of the driver 9. Further cooperating structures such as a ring 137 in the cavity 110 of the blocker 5 and a ring 139 on the connector 85 of the driver 9 may also assist preventing tilting.

The sub-assembly 5,7,9 is then arranged in the cavity

17 of the base 3, wherein the connector 129 of the blocker 5 is received in and extends through the central opening 23 of the base 3, and the protrusions 127 are received in the radial narrow portions of the protrusion 39 on the bottom wall 21 of the base 3. Relative tilt of the blocker 5 and the base 3 is preferably prevented, such as by cooperating surfaces. Here, the protrusions 127, 135A, 135B bear against the bottom wall 21 of the bas 3 providing plural contact points. The protrusions 135A, 135B are arranged radially outside of the protrusion 39 on the bottom wall 21 of the base 3. The base 3 and blocker 5 may comprise further cooperating structures for support against tilting, e.g. bearing against the protrusion 39 and/or the bottom wall 21 of the base 3.

When thus assembled further, the blocking stops 121A, 121B resiliently bear against the inside of the outer wall 19, thus being in one radial position, and the blocker 5 may rotate in the base 3 until the blocking stops 121A, 121B can flex outward into the recesses 35 in the outer wall 19, and thus to another radial position, thereby relaxing the arms 119A, 119B. In this position further relative rotation of the base 3 and the blocker 5 is blocked by (the blocking stops 121A, 121B of) the arms 119A, 119B engaging the protrusion 33 between the recesses 35. Hence, in the latter situation a rotational indexing

position is determined, wherein each of the opposing arms 119A, 119B blocks rotation in one of both directions of rotation and the arms 119A, 119B, and the protrusions 33 and/or recesses 35 form first sets of cooperating indexing members. Note that the protrusion 33, the recesses 35 and (the blocking stops 121A, 121B of) the arms 119A, 119B may be formed such that, in such indexing position, some play may exist between these portions so that these portions may be relaxed and not be subject to stress.

The (connector 71 of the) spindle part 11 is snapped into (the connector 85 of) the driver 5 and the lid 13 is fixed to the base 3 for closing the system 1. Alternatively, the lid 13 may be fixed first and the spindle part 11 may be attached to or detached from the driver 9 through the lid 13 in a particular relative angular position of the driver 9 and the lid 13, wherein the protrusions 75 fit the "ears" of the hole in the lid 13. Such (dis-) connection is not possible with the lid 13' of Figs. 4-5. Operation of the indexing system 1 is explained hereafter, with reference to the schematic indications in Figs. 8A-8D, representing a top view along the axis of rotation A.

Fig. 8A shows the system 1 in an indexing position as described above, wherein an indexing protrusion 33 is received between indexing arms 119A, 119B of the blocker 5. Further, another indexing protrusion 33, and an outline of the driver 9 with its control portions 93A, 93B are visible. For clarity, other elements are not shown in Figs. 8A-8D.

To operate the system 1 for switching, the driver 9 is rotated with respect to the housing 3; 13, e.g. clockwise as in Fig. 8B. Via the coupling of the spring 7, a rotational force is exerted on the blocker 5. Since rotation of the blocker 5 with respect to the housing 3; 13 is blocked by the indexing arm 119A engaging the indexing protrusion 33, the side face 103A of the driver 9 engages the spring end 78A and the other spring end 78B engages the side face 115A of the blocker 5 so that a

significant torsion spring force in azimuthal direction between the driver 9 and the blocker 5 may be developed. The equal axial positions of the side faces 103A, 115A and both spring ends 78A, 78B prevent relative tilt of the driver 9 and blocker 7. When the driver 9 is rotated further with respect to the blocker 5, e.g. to about 80-85 degrees relative rotation from the initial situation (compare Figs. 8A-8B) , the control portion 93A engages (a control portion 123A of) the indexing arm 119A and presses the free end of the arm 119A radially inward from its first radial position to a second radial position closer to the axis A. The circumferential slot 101A (Figs. 6, 7) accommodates the spring tip 78B at such large angles of relative rotation of the driver 9 and the blocker 5.

When the arm 119A is pressed past the protrusion 33 the blocker 5 is free to rotate clockwise relative to the housing 3; 13 under the driving force of the spring 7 and the driver 9. When the blocker 5 rotates with respect to the housing, 3; 13 the resiliency of the arm 119B allows radially inward deflection of the free end of the arm 119B past the subsequent indexing protrusion 33 and latching behind it, whereas the other arm 119A flexes outward again after losing contact with the control portion 93A to "catch" the subsequent indexing protrusion 33, see Figs. 8C-8D. As a result, the blocker 5 is forced to the subsequent indexing position wherein the cooperating indexing members block further rotation, here the arms 119A, 119B being (again) arranged around a corresponding indexing protrusion 33, see Fig. 8D. A counter-clockwise rotation of the driver 9 will bring the system 1, likewise, back to the situation of Fig. 8A. This procedure can be repeated with each indexing protrusion 33 of the system 1.

As visible in Figs. 8A-8B, separate control portions

93A, 93B, 123A, 123B may not be required, as long as the radial displacement of the indexing members is provided. However, distinct control portions 93A, 93B, 123A, 123B assist defining the relative rotational position (angle) between the driver 9 and blocker 5 in which a radial displacement may be effected.

This improves switching reliability. The optional faces 95A, 95B engage and guide the control portions 123A, 123B in radial direction at a relative rotation of the driver 9 and blocker 5. improving smooth and accurate switching.

Arranging the cooperating indexing members 33, 35,

119A, 119B, radial to the moving parts 5, 9 allows reduction of the construction height of the system 1.

To provide smooth switching, account may taken of the deflection of the arms 119A, 119B, corresponding to a rotation about the cantilever point of the arms 119A, 119B on the body of the blocker 5. E.g., at least a portion of (a blocking stop 121A, 121B on) the free ends of the arms 119 and/or the indexing protrusion 33 may comprise a surface arranged substantially tangential to the relative displacement of the engaging portions of the respective indexing portions 121A, 121B and 33. This prevents having to overcome a force barrier and/or wear when switching. Possible torsion may be accounted for likewise with bevels and/or chamfers.

The faces 95A, 95B of the driver 9 of Figs. 1-7 facilitate engagement of the control portions 93A, 93B with the protruding control portions 123A, 123B on the blocker 5 of Figs. 1-7. As shown in Figs 8A-8D, the driver may also directly engage indexing members 119A, 119B, without further control portions. To prevent stress on the arms 119A, 119B, e.g. due to sudden contact between the arms and the protrusions, further blocking elements may be provided. In the embodiment of Figs. 1- 7, in one indexing position, pairs of blocking surfaces 37A and 125A or 37B and 125B, respectively, may oppose each other and block rotation in one particular direction of rotation, while - disregarding other indexing members- allowing rotation in the opposite direction until stopped by the other pairs of blocking surfaces 37B and 125B or 37A and 125A. Thus, an angular degree of freedom rotation is restricted to the relative positions determined by these blocking surfaces 37B and 125B or 37A and 125A, which here corresponds to another indexing position. Hence the fixed protrusions 39 and 127 provide cooperating indexing means that are substantially immovable. Here, the blocking surfaces 37B and 125B and, respectively, 37A and 125A, define a maximum angle of rotation of the blocker 5 with respect to the base 3 of about 90 degrees, corresponding to two indexing positions defined by adjacent sets of protrusions 33 and

recesses 35 that are engageable by the corresponding structures on the arms 119A, 119B. However, any other desired angular range may be provided.

It is noted that these further blocking elements 39, 127 are arranged close to the bottom wall 21 of the housing 3; 13. Thus, relatively large forces originating in an apparatus connected to the blocker 5 may be dissipated close to the origin of the forces by direct interaction of parts that are robust objects. Further, cooperating protrusions and recesses in and/or on the bottom wall 21 and (the bottom of) the blocker 5 allow reduction of the construction height.

Further, optional cooperating structures restricting the maximum angle of relative rotation of the lid 13 and the driver 9 about the axis A may be provided. Here, such

cooperating restricting structures are formed by the protrusions 64 of the lid 13 being at least partly received in the recesses 84 of the driver 9. Different, more and/or less such optional cooperating structures may also be provided.

Figs. 9A-9D show a blocker 5', substantially similar to the blocker 5 of Figs. 1-7. Here, the second wall 109' comprises portions 141A' , and 141B' extending in circumferential direction from the wall 109' , partly overlapping the arms 119A' and 119B' . Thus, additional circumferential material is provided which may assist preventing tilting and/or which may increase robustness of the blocker 5' . Further, best seen in Fig 9B representing the detail indicated in Fig. 9A, the blocking stops 121A' , 121B' each comprise a beveled face 143A' , 143B' , to account for possible torsion of the arms 119A' , 119B' when the control portions 93A, 93B of the driver 9 engage the control portions 123A', 123B' of the blocker 5'. This facilitates smooth and accurate switching. Side faces 145A' , 145B' of the blocking stops 121A' , 121B' are arranged at an angle a' with respect to a purely radial direction to the axis A, so that they are

substantially tangential to their displacement relative to the indexing portions 33.

Visible in Figs 9C and 9D, the blocker 5' comprises a connector 129' having a recess 145' with a substantially non- circular, here substantially square, cross section. The blocker 5' comprises substantially azimuthal recesses 147A' and 147B' having end faces 125A' , 125B' respectively. The blocker 5' also comprises optional slightly raised surface portions 149' and 151' , which here extend around the axis A.

Figs. 10 and 11 show different bases 3" and 3"' for use in the disclosed system. The bases 3", 3"' are substantially similar to the bases 3, 3' of Figs. 1-2B and 4-5, however comprising somewhat different connection structures 29", 30"; 29"', 30"'. Further, the base 3" of Fig. 10 comprises a

substantially flat bottom wall 21" from which protrusions 39" protrude upward in axial direction from the bottom wall 21". The base 3"' of Fig. 11 lacks such protrusions.

The blocker 5' and the base 3" are formed such that each protrusion 39" is receivable in a recess 147A' and 147B' , respectively. In use, the protrusions 39A" and 39B" and the end faces 125A", 125B" form cooperating blocking structures

determining an angular degree of freedom for relative rotation of the blocker 5' and the base 3" about the axis A, similar to the blocking stops blocking surfaces 37A and 125A or 37B and 125B of the blocker 5 and bases 3, 3' shown and discussed before (not counting indexing positions) . Such blocker 5' and base 3" may be fit in a particularly small volume and/or require

particularly little height.

Since the base 3"' lacks the protrusions 39, the blocker 5' has full 360 degrees available for relative rotation of the blocker 5' and the base 3" about the axis A (not counting indexing positions). Thus, indexing members 33"', 35"' in any portion of the housing 3"' are available.

In an embodiment, the housing and/or blocker comprise separately fixable, preferably detachably fixable blocking structures to define different relative angular degrees of freedom, e.g. comprising plural holes in the bottom wall of the base in or through which pegs may be arranged to form

protrusions, the pegs possibly extending from a plate-like member arranged underneath the base.

Fig. 12 shows an underside of the base 3' of Figs. 4-5. The base 3' comprises a space 153' for accommodating a rotary contact (not shown) rotatably about the axis of rotation A. The base 3' further comprises four portions 155' for accommodating a stationary contact (not shown) such that a contact portion thereof protrudes into the space 153' , for being contacted by the rotary contact, while a connection portion thereof is accessible on the outside of the base 3' , allowing connecting the stationary contact to a conductor. The base 3' further comprises a plurality of exhaust spaces 157' in communication with the first space 155' via an opening 159' . Here the exhaust spaces 157' are exhaust channels, comprising a second opening or exhaust opening 161' at an outside surface of the base 3' . The exhaust spaces 157', possibly in combination with a

corresponding structure in a further portion of a switch

connected with the base 3' , facilitate exhaust of a spark plume and/or hot air which may be formed in the space 153', e.g. when (dis-) connecting the rotary contact and a stationary contact, see also WO 2009/12174 . ig. 13 shows a housing part for an alternative embodiment. The housing part comprises a base 3"" as a first portion and an insert 163 as a second portion. The top side of the base 3"" (not visible in Fig. 13) may be formed according to any suitable embodiment of a base, e.g. according to any one of Figs 1-2B, 4-5 or 10-11. However, the housing part may also be formed differently for use as another housing part, e.g. as a housing module for a rotary switch. The base 3"" comprises a space 165 for receiving at least part of the insert 163. Here, the space 165 comprises a top wall 167 which here also forms the bottom wall 21 of the recess of the base 3"" for receiving further parts such as a blocker 5 and driver 9 as described above, also comprising an opening 23 for connection between a blocker 5-5' and a further spindle portion (not shown) . The base 3"" also comprises coupling structures, here a ring 169 protruding from the top wall 167, and channels 171 for coupling with the insert 163. The base 3"" further comprises portions 155"" for accommodating a stationary contact (not shown) as in Fig. 12.

The insert 163 comprises a first portion 173 providing a space 153"" for, at least when the insert 163 is received in the base 3"", accommodating a rotary contact (not shown) rotatably about the axis of rotation A. The first portion 173 comprises an opening 174. The insert 163 further comprises optional second portions 175, here extending from the first portion 173, providing a plurality of exhaust spaces 157"" with first openings 159"" connecting to the space 153"" and second openings 161"" away from the space 153"".

For assembly of the housing part the insert 163 is arranged in the space 165 and the channels 171, wherein the ring 169 fits in the opening 174 and the second openings 161"" are arranged at an outside surface of the base 3"". Both portions 3"", 163 may be attached with a friction fit and/or any other attachment method, e.g. a snap fit, gluing, welding and/or using fasteners etc.

In the housing module further structures may be provided. Here, nuts 177 are arranged between the first and second portions 3"", 163 and received in corresponding

structures therein, for attachment of the housing part to a further object.

When the housing part is assembled with the insert 163 being received in the base 3"", the underside of the shown housing part is substantially identically shaped to the underside of the basis 3' of Fig. 12, e.g. facilitating exchange. The first and second portions 3"", 163 being separate parts allows optimising and/or exchanging both portions

independently, e.g. in case of different wear, or to provide one portion, here the insert 163, with better electrical insulation properties and/or being more robust against spark products such as hot plasmas and/or ultraviolet radiation, whereas the other portion, e.g. here the base 3"", may be more robust against mechanical loads. It is noted that different inserts 163 may be provided to allow (retro-) fitting one base for compatibility with different further objects.

A base and insert may be formed for be arrangeable in different relative positions and/or such that the insert provides blocking portions for defining a relative angular range of freedom. The combination of both options allows the

definition of different relative angular ranges of freedom.

The invention is not restricted to the above described embodiments which can be varied in a number of ways within the scope of the claims. For instance, the driving and driven parts may comprise cooperating locking parts to fix the parts

together, yet allowing relative rotation, e.g. with latches engaging one or more circumferential grooves.

The assembly may be assembled from a single side, stacking the parts on top of each other without making sub- assemblies first, which also facilitates automated assembly. The shown bases, insert, blockers, drivers and lids, possibly also the spring, may each and/or all be formed by moulding technigues and may be made with one or more suitable polymer materials, providing electrical insulation and reducing manufacturing costs.

Elements and aspects discussed for or in relation with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise .