FR2638890A1 - ROTATION LIMIT SWITCH - Google Patents

Abstract

This switch is of the type comprising a support frame 1, a threaded spindle 15 rotatably mounted in the support frame 1, a spindle nut 31 sliding along the threaded spindle 15 during its rotation and provided with a control cam 33 , as well as a switch 37 located on the support frame 1, actuated by the control cam 33. The spindle nut 33 is guided fixedly in rotation, but sliding axially, on a guide element 25 rotatably mounted on the frame -support 1, on the same axis as the threaded spindle 15, and the guide element 25 is connected in rotation and rotating in the same direction as the threaded spindle 15, by means of a reduction gear 41, 43, 45 reducing its speed of rotation relative to that of the threaded spindle 15.

Description

! Limit switch in rotation

  The subject of the invention is a limit switch

  comprising a support frame, a threaded spindle rotatably mounted in the support frame, a spindle nut sliding along the spindle fluttered during its rotation, and provided with a control cam, and a switch located on the frame-support, actuated by the control cam. A rotary limit switch of this type is known from German Patent No. 27 14 493. This rotary limit switch comprises a rotatably driven shaft which passes through a helical spring fixed to the shaft only by its two ends. . On a guide rod whose axis is parallel to the shaft, is slidably mounted a control part which is threaded by an extension, on the coil spring and which is screwed along the coil spring during rotation of the shaft . The control part forms a control cam for

  a switch placed in the area of one end of the coil spring

  dal. The shaft carries, in addition, a stop cam which drives tangentially

  the control part in the end position and which ensures

  a movement actuating the switch.

  The known rotation end switch is relatively mechanically fragile. In addition, the number of rotations of the shaft on which it can be set to reach the end position,

  is relatively small when it is necessary to choose for the coil spring wire

  of sufficiently large diameter, suitable for working conditions

severely.

  The object of the invention is to provide a rotation limit switch with a simpler and more robust construction that can be adjusted

  on a larger rotation, despite relatively

  duced. Starting from the rotary end-of-travel switch of the aforementioned type, this object is achieved according to the invention because the spindle nut is guided fixed in rotation, but slides axially on a guide element mounted to rotate on the frame. on the same axis as the threaded spindle, and the fact that the guide element is coupled rotatably fixed and rotating in the same direction as the threaded spindle, by means of a gear reducer reducing its speed of rotation. rotation relative to that of the threaded spindle. In a rotating end-of-travel switch of this type, the guide element rotating in the same direction as the threaded spindle, has a lower rotational speed, reduces the feed of the spindle nut by rotation of the spindle threaded. This corresponds to a virtual reduction of the pitch of the threaded spindle, without diminishing its mechanical stability. The continuous rotation of the spindle nut can also be used to increase the control stroke when actuating

of the switch.

  The guide member may be for example a guide bracket or a similar member of axis parallel to the threaded spindle and rotating about its axis of rotation, the spindle nut being slidably guided on said guide bracket. Advantageously, however, the guide element is an axially split sheath which surrounds the threaded spindle and through which slot the spindle nut control cam protrudes and which guides the spindle nut to the sheath. slit. The slit sleeve protects the threaded spindle and may form a lubricant reservoir if required. The component, the limit of rotation of which must be controlled, for example the cable drum of a hoist, is generally coupled by complementarity of form with the rotary limit switch, so that it must be adjusted after assembly, with respect to the component to be controlled. In conventional limit switches, such as that of German Pat. No. 27 14 493, snap-in couplings are provided in the drive channel of the threaded spindle.

  removable axially, on the same axis as the threaded spindle. But the operation

  However, the adjustment amount of the known end-of-travel switch is relatively long, when the threaded spindle has to be moved over a long stroke. In a preferred embodiment of the invention, the threaded spindle and the guide member can be adjusted independently of each other, which greatly shortens the setting operation. In this embodiment, the gear reducer is a gear transmission which comprises gear wheels wedged at one end of the threaded spindle on the one hand and the guide element on the other hand, and which meshes with associated gear wheels, placed on the same axis and connected in rotation. The threaded spindle and the guide element are mounted at least in the region of their adjacent ends of the wheels

  toothed, in a common bearing element, adjustable elastically

  to the axis of rotation and emerge from the driving gears

  during a deflection of the bearing element. The ends of the threaded spindle of the guide element remote from the gear reducer carry

the control organs.

  The bearing element can, in the simplest case, be a cousin

  sinet which is fixed, for example, on the support frame, housed in elastic rings. But since the transverse thrust that occurs during training can reduce the control accuracy, in

  In cases where high precision is required, the bearing element is

  advantageously a guiding neck sliding in a guide opening of the support frame, perpendicular to the axis of rotation of the spindle

  threaded. A spring resting on the prestressed support frame

  sinet in the meshing direction of the gears. The guide opening prevents transverse displacements in the thrust direction of the gears.

  The switch can be directly attached to the support frame.

  In particular in embodiments comprising an element of

  bearing moving perpendicular to the axis of the spindle, it can, all-

  However, there may be control tolerances when high accuracy is required, if the threaded spindle can move relative to the switch even slightly. Command tolerances can be obtained

  particularly narrow if the switch is attached to the landing, preferably

  whether at both ends of the guide element or the spindle

  ture, bearing elements which are orientable elastically

  to the axis of rotation and if, for example, the two bearings

  are connected to a cross-piece to form a unit on which the

  switch. The relative position of the switch relative to the threaded spindle

  is therefore maintained independently of its transverse displacement.

  In a variant of the embodiment described above, in

  which the coach link can be separated in the demul-

  In order to adjust the rotary limit switch, it is provided that the threaded spindle and the guide member are mounted in the region of their ends remote from the gears, in a common ball bearing, allowing movement. pendulum or limited tilting and which allows pivoting of the threaded spindle and the guide member perpendicular to the axis of rotation. The ball bearing makes it possible to fix the threaded spindle and the guide element in a particularly precise manner with respect to the support frame, and thus makes it possible to obtain particularly reduced control tolerances. It has been found that the necessary bearing clearance, for example 0.1 mm, of a sliding bearing

  ordinary, cylindrical, but relatively narrow, forms a bearing characterized

  pendular tick, usable for the present applications, since the height of the teeth of the gears and, therefore, also the tilting angle of the threaded spindle are very small. It turned out, moreover,

  advantageous that the ball bearing has an outer ring

  both in the form of an axially split, radially elastic split ring appendix which is fixed to the support frame, for example formed of a single

  piece, and which surrounds, by an outer casing shaped spherical

  the inner ring connected to the guide element. When mounting the limit switch in rotation, the guide element can

  be clipped by its inner ring into the outer ring. An elastic ring

  The tick on the outer ring squeezes the outer ring against the inner ring and compensates for initial tolerances as well as those due to wear. To adjust the rotary limit switch, the gear wheels of the gear reducer must be oriented relative to each other so that their teeth mesh with each other again after adjustment. In the most unfavorable case, the teeth can be displaced by half a tooth division, which leads to a

  corresponding adjustment error when orienting the gears.

  To be able to compensate for this inaccuracy of adjustment, provision is made in a preferred embodiment of the invention for the switch to be pivotally guided on a guide pin of the support frame, on the same axis as

  the axis of rotation of the threaded spindle, and can be fixed, on the framesup-

  port, in an adjustable pivoted position. Thanks to this simple means, it is possible not only to compensate for the positional error resulting from the division of the teeth, but also the games which add up in the steps of

  the guide element, the threaded spindle and the bearing element.

  In a preferred embodiment there are provided on the support frame several units each constitules of a threaded spindle, a spindle nut, a switch and a guide element rotatably connected to the threaded spindle, by a multiplier, which units are all driven by a common input shaft. It is thus possible to provide, for example, limit switches for the two directions of rotation, for emergency shutdown or a cut-off required by operation. The axes of the pins of these units are advantageously parallel to each other and distant from the same distance from the axis of rotation of a mounted control cam

  rotating on the support frame, so that with a single cam com

  you can adjust all the units one after the other. It is understood that it is also possible to provide other cams on a common cam body and uncouple, from the input shaft, all the units at the same time.

time.

  The threaded spindle may have a single or multiple thread

  tiple. If the winding direction of the turns is the same over the entire length

  of the spindle, the switches must be placed in the area of the

  Moved the threaded spindle. The location of the switches defines the direction of rotation of the threaded spindle. In an advantageous variant of the invention, the threaded spindle is a cross threaded spindle whose end thread zones are provided with inverting threads. A rotating end-of-travel switch of this type can be used in both directions of rotation, regardless of the arrangement of the switches, particularly when the switch is placed in an area between

  the inversion nets, for example near the center of the spindle

  ted. Despite a constant direction of rotation of the threaded spindle, the spindle nut performs a back-and-forth motion that can be used to extend the rotational travel of the limit switch when

  the control cam and the cross thread as well as possibly the

  Reducer port are calculated such that the control cam operates the switch only in one of the reciprocating strokes of the spindle nut constituting a cycle, while it does not operate the switch in other cycle adjustment runs. For example, the control cam can move, in one of the axial directions of displacement of the spindle nut, the side of the actuation of the switch, while the control cam passes in front of the switch, in the opposite direction of movement, on the side

  the threaded spindle away from the actuating side. The cycle can

  take two or more races. It is essential here that the proper sizing of the threaded spindle threading alone allows the gearshift ratio of the limit switch to be varied, without the need to change the gear reduction gear provided on the input side.

  It has proved advantageous that the gear reducer is a transmission

  planetary gears as this allows, for a given total ratio, to reduce the diameter of the gears set on the threaded spindle or

  on the guide element and thus reduce the total diameter of the inter-

  limit switch in rotation. Thanks to this means, we also avoid

  intermediate gear wheels mounted on the support frame. -

  In an advantageous variant, it is intended to articulate, on the inter-

  switch, an intermediate lever to actuate the switch, which detects the control cam of the spindle nut, with a cam feeler head. The cam feeler head which, to reduce wear, is preferably a rotatably mounted roller, virtually increases the slope of the driving surface of the control cam, and hence the control speed. It is thus possible to increase the contact opening speed of the switch sufficiently to reach the speed of control of the snap switches and, therefore,

  use simpler switches. This means finally allows

  relatively wide control faces of the control cam and, therefore, actuation of the switch, with a clearance of the shaft of

  entry from one to a half rotation.

  To provide protection against mechanical overload, a slip coupling can be provided in the drive path

  of the limit switch in rotation.

  Embodiments of the invention are described below, in more detail with reference to the accompanying drawings, in which Figure I is a longitudinal sectional view of a rotary limit switch with drive mechanism. filament pin, along the line 1-I of Figure 2; Figure 2 is an axial view of the rotary end switch in the direction of the arrow II of Figure I; FIG. 3 is a sectional view of the end-of-travel switch rotated in the adjustment position, along the line 111-111 of FIG. 4; Figure 4 is a sectional view of the rotational end switch of Figure 1, but in adjustment position, along the line IV-IV of Figure 3; Fig. 5 is a side view of a variant of a rotational end-of-travel switch with cross-threaded spindle and a partial sectional view along the line V-V of Fig. 7; FIG. 6 is a sectional view of the end-of-travel switch

  in rotation of FIG. 5, along the line VI-VI of FIG.

  the gearbox is removed;

  FIG. 7 is a front view, partially open, of the

  limit switch in rotation, seen in the direction of the arrow VII of Figure 8; Figure 8 is a sectional view of the rotational limit switch of Figure 1, but shown in the adjusting position, along the line VIII-VIII of Figure 7; FIG. 9 is a front view, partly open, of another variant of a rotary limit switch with crossed threaded spindle, and FIG. 10 is a sectional view of the end-of-travel switch.

  in rotation, along the line X-X of FIG. 9.

  The rotary limit switch described firstly with reference to FIGS. 1 to 3 comprises a box-shaped support frame I having front support flanges 3.5 which are interconnected by diagonals 7. On the case frame I are attached four

  end-of-stroke units 9 which are driven together by a drive shaft

  13, through a transmission II. Each of the end-of-stroke units 9 comprises a threaded spindle 15 having an axis parallel to the input shaft 13 and located at the same distance therefrom, which is rotatably mounted, by its ends 17, 19, in bearing bores 21, 23 of a cylindrical slot sheath 25 surrounding coaxially the threaded spindle 15. The slotted sheath 25 is, in turn, rotatably mounted on

  the same axis as the threaded spindle 15, in bearings 27, 29 of the flanges.

  3.5 support. On the threaded spindle 15 is placed a spindle nut

  31 which emerges, by a control cam 33, from an axial slot 35 which is

  in the slot sheath 25, and which guides the axially slidable pin nut 31 axially slidable relative to the slot sheath 25. In the region of the support flange 3 remote from the transmission 11, each unit of end of stroke 9 has a switch 37 which can be actuated by the control cam 33 of the spindle nut 31, by an intermediate lever 39 (Figure 2). The slot sheath 25 carries, on its transmission-side end, a toothed wheel 41 which meshes with the smaller-diameter partial wheel of a stepped gear 43. The threaded spindle 15 emerges, at its end 19, from the slot sheath. 25 and carries, at the protruding end 19, a toothed wheel 45 which meshes with the partial wheel of larger diameter of the stepped gear 43. The stepped gear 43 is mounted freely rotating on the same axis as the gear shaft. 13, on a pin 47 which is supported on the one hand in

  the support flange 5 and secondly in an opening of the shaft of

  The staggered gear wheel 43 couples, rotatably secures, the slit sleeve 25 and the threaded spindle 15 and forms, with the gear wheels 41, 45, a reduction gear which drives the slit sleeve 25 in the same direction as the threaded spindle 15, but with a reduced speed. For the driving connection of the stepped gear 43, with respect to the input shaft 13, a toothed wheel 49 which is pressed by a spring 51 is provided on the same axis as the stepped gear wheel 51. against the side faces of the stepped gear 43, which forms therewith a sliding coupling. The toothed wheel 49 meshes with the smaller-diameter partial wheel of a stepped gear wheel 53 which is mounted on an axis

  parallel to the input shaft 13, on a pin 55 integral with the housing.

  The larger diameter wheel part of the stepped gear 53

  meshes with a toothing 57 of the input shaft 13.

  When driving the input shaft 13, the stepped gear 43 is driven with a reduced speed of rotation by the stepped gear 53 and the toothed gear 49. The stepped gear 43, in turn, drives in rotation the threaded spindle 15 and the slotted sleeve 25, the spindle nut 31 being screwed along the threaded spindle 15, due to the reduced speed of the slotted sleeve 25. The switch 37 is actuated when the Control cam 33 reaches the intermediate lever 39. The axial advance stroke of the control cam 33, for each rotation thereof, is certainly relatively small, but sufficient to ensure, despite the tolerances, that the intermediate lever 39 is covered axially as radially, only for a defined rotation. The unit

  end-of-race9 has, as a whole, a great power of separa-

  tion. The threaded pins 15 of the end-of-stroke units 9 have a two-by-two opposite winding direction of turns, as shown at 59 in FIG. 1, to form end-of-stroke pairs for both directions of rotation. When the spindle nut 31 of one end-of-stroke unit 9 of each pair is in its end position actuating the switch 37, the spindle nut 31 of the other end-of-stroke unit

  9 is, as shown in Figure 1, in the opposite position.

  In order to be able to adjust the end-of-stroke units 9 separately, the drive connection of the stepped gear 43, with respect to the gear wheels 41, 45 of the end-of-travel units 9, can be suppressed so that the threaded spindle 15 and the slot sheath 25 can rotate freely. The bearings 27, 29 are, in this case, guided sliding, radially with respect to the axis of rotation of the stepped gear 43, in guide openings 61, 63 of the two support flanges 3.5 and are prestressed, by springs 65, 67, for meshing the toothed wheels 41, 45 in the stepped gear 43, towards its axis of rotation. In the extension of the axis of rotation of the stepped gear 43, a shaft 71 which projects from the support flange 3 by a bearing opening 73 is rotatably mounted on a pin 69 of the support flange 5. The pin 69 is placed in an opening of an eccentric cam driven in rotation by the shaft 71, which cam can be brought into engagement with the various bearings 29, by axial sliding and rotation of the shaft 71, and which presses the bearings 29 to move them away from the axis of the stepped gear 43 and to bring them into a position in which the gear wheels 41, 45 are out of the toothing of the stepped gear 43, as shown in FIG. 4 for the gear unit. upper limit switch 9. In this position, the threaded spindle 15 freely accessible to its

  end 17 and the slit sleeve 25 carrying, at the corresponding end,

  dante, a manual ring 77, can be turned freely to adjust the spindle nut 31 in its axial position and also adjust the position

  in rotation of its control cam 33.

  As more specifically shown in Figure 2, the switch 37 is fixed on a flange 79 of the bearing 27, so that any transverse movement of the spindle axis, for example due to the pressure of the sidewalls of the gears 41 , 45, do not affect control tolerances during operation. The shaft 71 is prestressed axially, in the direction opposite to the meshing direction of the cam 75, by a spring 81 placed in the bearing opening of the pin 69, so that the cam 75 does not interfere with the normal operation of the cam. the limit switch in rotation. The stops 83, 85 limit the travel of the shaft 71. As indicated in FIG. 3, by a dotted line, the cam body 75 may also comprise several cams for actuation.

  common of all end-of-race units 9.

  A variant of the rotary limit switch of FIGS. I to 4 is described below. It differs from this limit switch only by the type of threaded pins and the way in which the switches are fastened. The corresponding elements are designated by the same references which are followed by the letter a. To explain the constitution and mode of operation of these elements, reference is made to

the description of Figures I to 4.

  While the threaded pins 15 of FIGS. 1 to 4 have a thread 59 whose winding direction of the turns is the same, the threaded pins a of the rotary limit switch of FIGS. 5 to 8 are

  provided with a cross thread 85 whose threads of opposite direction is

  run along each other, at both ends of the threaded spindles 15a, by thread transition zones 84. With a constant direction of rotation of the threaded spindles 15a, the spindle nuts 31c move it back and forth between both ends of the threaded pins 15a. The switches 37a are fixed approximately in the middle of the threaded pins 15a, on sleepers 86 (Figure 5) which connect the two bearings 27a and 29a guided sliding perpendicular to the spindle axis, to form a unit. The pitch of the cross threading 82 of the threaded spindles 15a are identical, It the dimensions of the control cams 33a and the reduction ratio of the slit sleeves 25a rotatably connected, with the threaded spindles 1 5a, by the toothed wheels 41a, 43a and 45a are chosen in such a way that

  control cams 33a pass in front of and near the levers inter-

  39a of the switches 37a, only in one direction of their axial displacements, while in the other axial direction, they pass in front of the intermediate lever 39a and, therefore, in front of the switch 37a,

  to reach on the side of the threaded pins 15a away from the levers inter-

  mediators 39a. This increases the factor 2, compared to the limit switch of FIGS. I to 4, the total stroke and therefore the number

  of rotations to control the input shaft 13a.

  In contrast to the rotational limit switch of FIGS. 1 to 4, the toothed wheel 49a is integrally assembled to the stepped gear 43a, after the coupling effect of friction. It has been found that with appropriate teeth for the wheels

  teeth 41a, 43a and 45a, their teeth provide the function of a coupling

  safety devices and protect the end-of-stroke units 9 against overloading. It is also possible to provide a toothing of this type for the switch of FIGS. 1 to 4, instead of the sliding coupling. Where appropriate,

  the switch of FIGS. 5 to 8 can also have a sliding coupling

  additional information. By using cross-threading, one can still access

  increase the total stroke by designing the gear reducer so that the control cam only actuates the switch after having traveled

  at least twice the length of the thread.

  Figures 9 and 10 show a variant of the switch

  rotation end of FIGS. 5 to 8 which differs from this interrup-

  mainly by the design of the reduction gear, the position of the threaded pins on the opposite side to the gear reducer and the type of attachment of the switches. The corresponding elements are designated by the same references as those of Figures I to 8, followed by the letter b. To explain the constitution and mode of operation, it is

  refers to the description on the one hand of Figures I to 4 and on the other hand

Figures 5 to 8.

  The rotary limit switch always comprises four end-of-travel units 9b whose switches 37b are actuated in the manner described above, by control cams 33b of the spindle nuts 31b, via threaded spindles. 15b with cross thread 82b. The spindle nuts 3 lb are guided, in turn, by slot sleeves 25b which, like the threaded pins 15b, are driven from an input shaft 13b, but with a reduced speed, by means of

of a gear reducer Ilb.

  In contrast to the rotary limit switch of FIGS. 5 to 8, the gear reducer I lb is a planetary gear transmission of which the sun gear 49b, formed in one piece, on the input shaft 13b is surrounded. on the same axis by a hollow wheel 87 formed on the housing 1b. A planet carrier 89 is rotatably mounted on a pin 47b having the same axis as the input shaft 13b. This planet carrier carries one, preferably several, planet carriers 53b rotatably mounted which mesh with a toothing 57b of the sun wheel 49b and with a toothing of the hollow wheel 87. The planet carrier 89 is assembled, of one piece,

  to the stepped gear 43b, also provided in the variants described below.

  above the rotary limit switch, whose larger diameter wheel meshes with the toothed wheel 45b wedged on the end 19b, transmission side, of the threaded spindle 15b. The smaller diameter wheel of the stepped gear 43b meshes, on the other hand, with the wheel

  toothed 41b keyed on the corresponding end of the slot sheath 25b.

  Compared to the reduction gear of the limit switches in rotation described above, a greater gear ratio can be obtained with the planetary gear transmission, so that smaller diameter gear wheels 41b, 45b can be used. Consequently, it is also possible to reduce the transverse dimensions of the casing 1b. In the exemplary embodiment shown, the totality of the rotary limit switch can be housed in a housing, in the cylindrical assembly,

  from which radially protrude only the switches 37b.

  To adjust the control positions, the gears 41b, 45b may in turn be output from the stepped gear 43b by means of the eccentric cam 75b keyed to the shaft 71b, as has been explained. upper. In contrast to the rotary limit switch of FIGS. 5 to 8, the transmission end ends of the slot sheath 25b are no longer completely surrounded by the guided pads 29b.

  radially in the guide openings 63b of the support flange 5b.

  The bearings 29b are bearing shells which guide the slot shells 25b, prestressed by springs 67b, only on the outer side. The inner bearing shells are formed on the support flange 5b. Slotted sleeves 25b and threaded pins 15b are mounted radially movable only on the near side of the transmission. On the far side of the lb transmission, the

  Slotted sleeves 25b are rotatably mounted in ball bearings 91.

  The ball bearings 91 allow tilting of slit sleeves

  b, on all sides and defined, when the toothed wheels 41b, 45b are deactivated

  coupled with the stepped gear 43b. Each of the ball bearings 91 comprises an inner bearing ring 93, in the shape of a spherical shaft,

  formed on the slot sheath 25b, which ring is housed in an ap-

  bearing bracket 95 formed in one piece on the support flange 3b. The bearing appendix 95 has a spherical inner surface that allows rotation of the slotted sheath 25b about the axis of the threaded spindle b, as well as tilting perpendicular to the axis of rotation. The axial slots of the bearing appendix 95 give it

  elastically, so that the inner ring 93 can be

  axially rattling when mounting the limit switch in the bearing appendix 95. On the outer casing of the bearing appendix 95 is placed an elastic ring 97 which clamps the bearing appendix radially. and which compensates for the initial support game as well as

due to wear.

  The division of the teeth of the toothed wheels 41b, 45b only allows predetermined adjustment steps when the spindle is adjusted in rotation.

  Threaded 15b and slot sheath 25b. For fine tuning and compensation

  tolerances in the drive train of the transmission, the inter-

  breakers 37b are mounted on switch supports 99 which are pivotally guided on bearing appendages 101, on the same axis as the axis of rotation of the threaded spindle 15b. Locking screws 103 which pass through the switch supports 99 in oblong holes 105 enable the switches 37b to be locked with respect to the housing 1b. On the switches 37b, are mounted, again, pivoting,

2638890O

  intermediate levers 39b extending approximately tangentially with respect to the slit sheath 25, which levers carry, at their free ends,

  cam heads 107 in the form of rotating rollers.

  Cam heads 107 make it possible to increase the operating speed of the switches 37b virtually and practically without wear. In addition, relatively large control cams 33b can be used to allow a delay in operating the switches from one to one rotation

  and a half, with respect to the input shaft 13b.

Claims (16)

Claims I - Rotating limit switch comprising a support frame (1), a threaded spindle (15) rotatably mounted in the support frame (I1), a spindle nut (31) sliding along the threaded spindle (15). ) during its rotation and provided with a control cam (33), and a switch (37) located on the support frame (1), actuated by the control cam (33), characterized in that the spindle nut (33) is guided fixed in rotation, but axially slidable, on a guide element (25) rotatably mounted on the support frame (1), on the same axis as the threaded spindle (15), and in that the guide element (25) is rotatably connected and rotates in the same direction as the threaded spindle (15), by means of a reduction gear (41, 43, 45) which reduces its speed of rotation relative to that of the threaded spindle (15).   2 - rotary limit switch according to claim 1, characterized in that the guide element is a slit sleeve (25), axially split and coaxially surrounding the threaded spindle (15), through the slot (35). ) which spring the control cam (33) of the spindle nut (31) surrounded by the slotted sleeve (25), which guides the spindle nut (31) on the slit sleeve (25).   3 - Limit switch in rotation according to the claim   I or 2, characterized in that the reduction gear (41,43,45) is a transmission   gear arrangement which comprises gear wheels (41,45) set at one end of the threaded spindle on the one hand and the guide element   (25) on the other hand, which meshes with gear wheels (43)   formed, associated, rotatably connected on the same axis, in that the threaded spindle (15) and the guide element (25) are mounted in a common bearing element (27, 29) which can be rotated elastically and perpendicularly   the axis of rotation, in the area at least of their two adjacent ends.   toothed wheels (41,45), and disengage the toothed wheels   (43) driven during a deflection of the bearing element (27,29).   4 - rotary limit switch according to claim 3, characterized in that the bearing element is a bearing (27,29) guided sliding in guide openings (61,63) of the support frame (1) perpendicularly to the axis of rotation of the threaded spindle (15), at least partially surrounding the axis of rotation, which pad is prestressed by springs (65, 67) resting on the support frame (1), in the meshing direction of the toothed wheels (41,45) provided at the end of   the threaded spindle (15) and the guide member (25).   - Rotary limit switch according to claim 4, characterized in that the switch (37) is held on the pad (27,29) and is guided movable therewith, perpendicular to the axis of the spit.   6 - Rotary limit switch according to claim 4 or 5, characterized in that it is provided at both ends of the element   for guiding (25a) or threaded spindle (15a), bearing elements (27a, -   29a) which are rotatable elastically perpendicularly to the axis of rotation, which bearing elements are connected by a cross member (86) to form   a unit, and in that the switch (37a) is fixed on the crossbar (85).   7 - rotary limit switch according to claim 3 or 4, characterized in that the threaded spindle (15b) and the guide element (25b) are mounted in the region of their ends remote from the wheels   teeth (41b, 45b), in a common ball bearing (91), allowing a movement   pendulum of the threaded spindle (15b), which bearing allows an oscillation   the threaded spindle (15b) and the guide element (25b) are perpendicular to each other. lair to the axis of rotation.   8 - Limit switch in rotation according to the claim   7, characterized in that the ball bearing (91) comprises an integral ring   (93) connected to the guide element (25b), with an outer envelope   spherical shaft and an outer ring (95) complements   kept on the support frame (lb).   9 - rotary limit switch according to claim 8, characterized in that the outer ring is a radially resilient, axially split bearing appendix (95), held on the support frame (1b), and in that an elastic ring (97) externally surrounds the appendix bearing (95).   - Limit switch in rotation according to one   according to any of claims 3 to 9, characterized in that   Mande (75) is rotatably mounted on the support frame (1), in that   two units (9) each consisting of a threaded spindle (15), a spindle nut (31), a switch (37) and a guide member (25) rotatably connected to the threaded spindle (15), by a multiplier (41,43,45),   are provided together on the support frame (1) around the cam   Mande (75), their spindle axes being parallel, and in that the common bearing elements (27,29) of the spindle nuts (15) and the guide elements (25) are radially precontraminable and movable towards the cam   control (75), and can move away from the control cam (75).   11 - Rotary limit switch according to claim, characterized in that the control cam (75) is guided axially movable and is preloaded by a spring (81) to pass bearing elements (29) associated with the cam control (75), in a rest position in which it is no longer engaged with the bearing elements (29).   12 - Limit switch in rotation according to one   conque of claims I to 11, characterized in that the switch   (37b) is pivotally guided on a guide stub (101) of the support frame (1b), on the same axis as the threaded spindle (15b) and can be fixed in   an adjustable pivoted position on the support frame (1b).   13 - Limit switch in rotation according to any one   conque of claims I to 12, characterized in that the threaded spindle   (15a; 15b) is a cross threaded spindle whose end regions of the   threads are provided with inverting threads (84; 84b).   14 - rotary limit switch according to claim 13, characterized in that the switch 37a; 37b) is placed in a zone   between the inverting threads (84; 84b).   15 - Rotary limit switch according to claim 13 or 14, characterized in that the reduction gear (Ila; lb), the control cam (75a; 75b) and the cross thread (82; 82b) are dimensioned such that so that the control cam (75) operates the switch (37a; 37b) only in one of the reciprocating strokes of the spindle nut (3a; 3b) constituting a cycle, while she does not operate   the switch (37a; 37b) during the other cycle adjustment runs.   16 - Limit switch in rotation according to any one   conque of claims I to 15, characterized in that the multiplier   (Ilb) comprises a planetary gear set which comprises a sun gear (49b) fixed on an input shaft (13b) rotatably mounted in the support frame (1b), a hollow wheel (87) fixedly mounted on the frame -support (lb) and a planet carrier (89) rotatably mounted on the support frame (1b), on the same axis as the input shaft (13b), at least one planet gear (53b) meshing with the sun gear (49b) and the hollow wheel (87) being rotatably mounted on said planet carrier, and in that the carrier (89) is rotatably connected to a stepped gear (43b) whose stepped wheels meshing with the toothed wheels (41b, 45b) set on the threaded spindle   (15b) or the guide member (25b).   17 - Limit switch in rotation according to one   1 conque of claims I to 16, characterized in that a coupling   slip (43,49,51) is foreseen in the training path of the demulti- plicant (41,43,45).   18 - Limit switch in rotation according to one   one of claims 1 to 17, characterized in that the surface of   the control cam (33) is long enough for   the control cam (33) actuates the switch (37) with a rotation set   addition of the input shaft (13) from one to one and a half turn.   19 - Limit switch in rotation according to one   of claims I to 18, characterized in that a lever interme-   39 through which the switch (37) is actuated, detects   both the control cam (33) with a cam feeler head having in particular the shape of a rotating roller (107), is articulated on the switch   (37), to increase the operating speed.