US3487708A - Device for converting a continuous rotary movement into some other movement in dependence on electrical signals - Google Patents

Description

Jan. 6, 1970 R. BEGUIN ETAL DEVICE FOR CONVERTING A CONTINUOUS ROTARY MOVEMENT INTO SOME OTHER MOVEMENT IN DEPENDENCE O L SIGNA Filed May 22, 1968 Sheets- .etl

N ELECTRICA Jan. 6, 1970 R BEGUlN ET AL 3,487,708 DEVICE FOR CONVERTING A CONTINUOUS ROTARY MOVEMENT INTO ":OME OTHER MOVEMENT 1N DEPENDENCE ON ELECTRICAL SIGNA Filed May 22, 1968 L5 6 Sheets-Sheet 9 Jan. 6, 1970 BEGUM ET AL 3,487.?08

lJl-ZVlCi'J FOR coNvuu'rlNu A CONTINUOUS ROTARY MOVEMENT lN'IO SOME OTHER MOVEMENT 1N DEPENDENCE. 0N ELECTRICAL SIGNALS Filed May 22. 1968 6 Sheets-Sheet 3 TO LS Sheet 4 3,487,708 VEMENT IN CAL SIGNA 6 Sheets ROTARY MO N ELECTRI CONTINUOUS EPENDENCE O RBEGUIN ETA!- TING A NT IN D {J m m A n DEVICE FOR CONVER liqiZ [I [14] Ill I. llllll It'll! Jan. 6, 1970 SOME OTHER MOVEME Filed May 22, 1968 Jan. 6, 1970 R BEGUM ET AL 3,487,708

DEVICE'POR CONVERTING A commuous ROTARY MOVEMENT m'ro SOME OTHER MOVEMENT IN DEPENDENCE on ELECTRICAL. SIGNALS Filed May 22, 1968 6 Sheets-Sheet 5 2 f. U o

Jan. 6, 1970 R. BEGUIN ETAL 3,487,708 DEVICE FOR CONVERTING A CONTINUOUS ROTARY MOVEMENT INTO SOME OTHER MOVEMENT IN DEPENDENCE ON ELECTRICAL SIGNALS Filed May 22, 1968 6 Sheets-Sheet 6 United States Patent Int. Cl. F16h 1/12, 27/64 US. Cl. 74-422 21 Claims ABSTRACT (IF THE DISCLOSURE A rotary converter comprises a continuously rotated input shaft fixed to a rotor comprising a plurality of pivoted members which can be pivoted in one sense or the other or left in an intermediate position on passing electromagnets as the rotor is rotated, depending upon electrical signals passed to the electromagnets. Each operating member after passing the electromagnets passes a cam arrangement which moves the operating member, in a manner depending on its position after passing the electromagnets, While the operating member is engaged with an output gear, to move the output gear in one sense or the other.

This invention relates to a device for converting a continuous rotary movement into some other movement in dependence upon electric signals.

It is an object of the invention to provide a device which can act as a mechanical power relay responding to low-power control signals and which avoids any need for electrical amplification of said control signals.

According to the present invention we provide a device for converting a continuous rotary movement into some other movement in dependence on electrical signals, including support means, an input member comprising a rotor rotatably mounted in said support for receiving said continuous rotary movement, a toothed output member movably mounted in said support means, a plurality of operating members mounted on said rotor for motion relative to the rotor, each operating member being arranged during rotation of the rotor to mesh with the teeth of said output member during movement through a limited range of angular positions with respect to the rotary axis of the rotor, means controlling movement of the operating members with respect to the rotor and providing a plurality of permitted modes of movement of the operating members as they pass through said limited range of angular positions to impart corresponding movement to the output member, means for selecting one of said modes of movement for each operating member in accordance with said electrical signals.

Several embodiments of the invention will now be described with reference to the accompanying drawings, wherein:

FIGURE 1 is an axial section on the line 1-1 of FIGURE 2 through one form of the device;

FIGURE 2 is a plan view of the device shown in FIG- URE 1;

FIGURE 3 is a section, to an enlarged scale, on the line 33 of FIGURE 1;

FIGURE 4 is a partial view of the device shown in FIGURE 1, the view being to an enlarged scale and in section On the line 4-4 of FIGURE 1;

FIGURES 5-9 show a moving tappet of the device shown in FIGURE 1 in five consecutive operating positions;

FIGURE 10 is a partial view of a cam of the device shown in FIGURE 1;

FIGURE 11 is a developed view of the cam shown in FIGURE 10;

FIGURE 12 is a diagrammatic view of the developed surface of the rotor of a second form of the device;

FIGURE 13 is a diagram showing various possible paths for the moving elements of the rotor shown in FIGURE 12;

FIGURE 14 is a diagram showing movements of the output member of the device shown in FIGURE 12 in response to a given programme of electric signals;

FIGURE 15 is a diagrammatic view of the rotor of a variant of the device shown in FIGURE 12;

FIGURE 16 is an axial section, along the line 16-16, of FIGURE 17, through a third form of the device;

FIGURES l7 and 18 are cross-sections on the lines 17 17 and 18-18 respectively of FIGURE 16;

FIGURE 19 is an axial section through the rotor of the device shown in FIGURES 16 to 18 On the line 19-19 of FIGURE 20; some items not being shown;

FIGURE 20' is a section on the line 20-20 of FIG- URE 19, and

FIGURES 21 and 22 are of details.

The device shown in FIGURES 1-l1 comprises an input shaft 1 running in two bearings 2 disposed in two parallel end plates or uprights 3 secured to a bed plate 4. Each bearing 2 comprises a cylindrical body 5 received in a bore in the corresponding plate 3 and a support finger 6 extends from one side of the body 5 parallel to the shaft 1. A plate 7 secured by screws 8 to the bearing body 5 bears on one side of each end plate 3 while a shoulder on the body 5 bears on the other side of each end plate. The end plate is thus clamped between the plate 7 and body 5 so that the latter are fixed in position when the screws 8 are tightened. After the screws 8 have been slackened, the angular position of the bearing 2, and therefore of the finger 6, in the end plate 41 can be adjusted.

The body 5 and finger 6 of each bearing 2 are made of an amagnetic substance, such as brass, and the fingers 6 bear two electromagnets 9, 10 each comprising a magnetic core 11 having the shape of a single helical convolution around the axis of the shaft 1. The ends of each core 11 form two continuous poles 12, 13 disposed in alignment with one another in a radial plane of the shaft 1. Screws 14 secure the cores 11 to the corresponding finger 6, and an energising winding 15 extends around each core 11 (FIGURE 3).

As shown in FIGURE 1 and FIGURE 4 a cylindrical rotor 16 whose periphery is formed with 24 evenly distributed longitudinal grooves 17 is rigidly secured to the shaft 1. Each groove 17 takes the form of a relatively narrow radial slot whose surfaces are parallel to one another. A hollow cylindrical guide 18 having a diameter of approximately three times the slot width extends parallel with the shaft 1 and on either side of each slot. Each groove 17 receives a plate-like rack member or rack 19 and a tappet 20. Each rack 19 comprises a base part, received in the corresponding groove 17, and teeth 22, which project radially from the rotor periphery. The inner edge of the rack 19 bears on the base 23 of the groove 17, and the rack 19 is pierced with a central circular aperture 24 receiving a ball 25 of the same diameter as the cylindrical guide 18. The ball 25 is also engaged in a circular aperture in the juxtaposed tappet 20 so that the ball 25 interconnects the tappet 20 and the corresponding rack 19, these two members being adapted to move views to an enlarged scale together axially along the groove 17, the :ball 25 sliding along the guide 18. The tappets 20 which project from both ends of the rotor are narrower than the depth of the grooves 17 and have provision for performing a limited pivoting movement around the balls 25.

The racks 19 are adapted to co-operate with a toothed wheel or gearwheel 26 rigidly secured to a shaft 27 which is perpendicular to the shaft 1 and which runs in bearings disposed in two cross-members 30 interconnecting the end members 3. The width b of the wheel 26 is slightly greater than the spacing between the racks 19 at the periphery of the rotor 16, and so the wheel 26 is always in engagement with at least one of the racks 19 (FIG- URE 4).

Each end plate 3 is formed with a cylindrical recess 31 extending to the end plate inside surface and receiving three rings 32, 33 and 34 which together form a cam adapted to co-operate with abutments 36 at the ends of the tappets 20. The rings 32 to 34 are retained in a predetermined angular position by screws 37 (FIGURE 3). The two cams are symmetrical and their shape will be described hereinafter in connection with the operation of the device, which is as follows:

The shaft 1 forming the input member of the device is rotated continuously so that the racks 19 move consecutively below the wheel 26.

When the tappets 20 are in an initial position shown in FIGURE 5, they are in a horizontal and centred position, and the racks 19 are in a centred position as shown in FIGURE 1. In this position the tappets 20, since their end faces 36b bear on the edges 32a of the rings 32, are locked axially and cannot pivot around the balls 25, since the abutment surfaces 36a bear on the cylindrical inside surfaces 33a of the rings 33 (FIGURE Referring now to FIGURES and 11, in an angular zone A corresponding to the movement of the tappets 20 past the pole surfaces of the electromagnet poles 12 and 13, the ring surface 33a is formed with a recess 33b permitting limited pivoting of the tappets 20. In the zone A, said pole surfaces are inclined radially inwards in the direction of rotation of the rotor, (anti-clockwise in FIG- URE 10) so that in section said surfaces are inclined from a radially outer level 37 slightly below the level of the tappet bottom edge 20b when the latter is in the horizontal position, to a radially inner level 38. The pole surfaces correspond to the surface generated by the edge 20b of a tappet as it pivots progressively during rotation of the rotor.

If neither of the two electromagnets is energised, the tappet 20 remains in its horizontal position as it passes by the magnets. If either magnet is energised, the tappet 20 tilts towards the energised magnet. In FIGURE 6 tappet 20 is shown tilted to the left, corresponding to energisation of the magnet 9.

In the zone A the ring edge 32a is formed with a recess 3211 whose downstream end, i.e. the end passed last by a tappet on the rotor moving anti-clockwise, takes the form of an inclined surface or ramp 32c (FIGURES l0 and 11). In a subsequent angular zone B extending over about 30, the recess 33b takes the form of a guide groove 39 comprising a first inclined portion 39a extending towards the rotor 16.

If the tappet 20 has tilted as shown in FIGURE 6, the right-hand abutment 36, which is in a slightly raised position, engages in the groove 39, with the result that, as the rotor rotates, the tappet 20 is shifted to the left (FIGURE 7). During this shift of the tappet 20 and as the rotor 16 continues to rotate, the left-hand abutment 36 of the tappet is in the end position shown in FIGURE 8, where the ball 25 and hence the rack 19 has shifted to the left by an amount P equal to the pitch of the teeth 22. Since the left-hand abutment 36 of the tappet bears on surface 32d of the ring 32, the righthand abutment 36 of the tappet is firmly engaged in the groove 39.

At the end of zone B the rack 19 engages in the teeth of the wheel 26 and remains thus engaged in the next angular zone C, in which the corresponding portion 39b of the guide groove 39 moves away from the rotor and gradually returns to its initial alignment, so that the tappet 20 shifts to the right, the wheel 26 therefore being rotated through an angle corresponding to its tooth pitch. At the end of zone C the rack 19 disengages from the teeth of the wheel 26 just after the next rack 19 has engaged with the teeth of such wheel.

In a zone D at the end of tappet movement to the right, the lefthand abutment 36 disengages from the ring 32 and the right-hand abutment 36 reaches an inclined surface or ramp 390 in the base of the groove 39, so that the tappet is restored to its initial horizontal position.

Consequently, as the rotor 16 rotates, the tappets 20 move past the poles of the two electromagnets. If neither electromagnet is energised at the time when a tappet passes by it, such tappet remains in its horizontal position, the corresponding rack 19 does not shift, and the movement of the rack 19 below the wheel 26 does not produce rotation thereof.

If, on the other hand, the left-hand magnet 9 is energised, the tappet 20 pivots theretowards, with the result that the tappet engages with the cams which shift the rack 19 by one tooth to the left before it engages in the wheel 26, then returns the rack to its centred position while the rack is engaged with such wheel, the same being rotated anticlockwise by one tooth (FIGURE 1).

If the right-hand magnet 10 is energised, the corresponding rack is moved first to the right, then returned to the left while in engagement with the Wheel 26, so that the same rotates clockwise by one tooth (FIGURE 1).

Any tappet 20 operating the Wheel 26 is in tension during this phase of its movements; consequently, the tappet moving to the right from the position shown in FIGURE 8, to the position shown in FIGURE 9 is pulled via its right-hand abutment 36. The tappets 20 can therefore be of thin construction.

In the device shown all that the electromagnets do is to pivot the tappets 20, and very little energy is required for this limited movement. The magnets have pole surfaces inclined in the direction in which the tappets pass by them, such surfaces acting on the tappets by magnetic attraction.

In a variant, the actuating magnets can be positioned to displace the racks directly either to engage the same with a cam finishing off the movement or to shift the racks when the same have already engaged with the output wheel.

For satisfactory operation, the signals transmitted to the electromagnets must be synchronised with the rotation of the input shaft, and this feature can readily be provided. The power available at the output shaft is independent of the power of the input electric signals, for the movement of the racks is produced by the cams and results from rotation of the rotor.

In a variant, the output wheel 26 can be replaced by a rack, in which event the maximum number of possible steps in any direction is limited. In further variants the gear wheel 20 is replaced by a helically toothed output wheel.

The device shown in FIGURES 12 to 14 is very similar to the device hereinbefore described except for its rotor, which is shown in FIGURE 12 and which has different operating members for operating the output wheel. The rotor 40, some of whose surface is shown in developed form in FIGURE 12, comprises a number of drive racks, as 41a, 41b, 41c, 41d, slidable in longitudinal grooves 42 in the rotor. The racks are adapted to co-operate, as they pass by, with a toothed wheel (not shown) similar to the wheel 26 and forming the output member of the device. The racks perform the function as the racks 19 of the device shown in FIGURES 1 to 11.

Interposed between the racks are actuating elements each comprising a tappet 44 juxtaposed with a guide plate 45. The tappets 44 perform the same function as the tappets of the device shown in FIGURES 1 to 11. Each tappet 44 is connected to the contiguous plate by a ball 46 rotatable in a hollow cylindrical guide in the rotor, the plate 45 and tappet 44 sliding axially in a longitudinal slot in the rotor. The tappets 44 can pivot through a limited angle around the balls 46 and are shaped like the tappets 20 of the device of FIGURES 1 to 11.

The difference between the device of FIGURES 1 to 11 and the device of FIGURES 12 to 14 is that in the latter device the racks 41 engaging with the output wheel are disposed not on plates contiguous with the tappets 44 but on independent plates interposed therebetween.

Each rack 41 is connected to the two plates 45 on either side of it by a connecting lever 49, and each lever 49 is pivotably mounted by way of a central aperture on a pin 50 engaged in the corresponding rack. The levers 49 have two equal arms 51, 52 which terminate in round heads engaging in recesses 53 in the plates 45. Consequently, the axial position of each rack 41 depends upon the axial position of the two plates 45 on either side of it. For instance, the rack 41a disposed between two plates 45 which are in a central position is itself in a central position, whereas the rack 41b disposed between a centred plate 45 and a plate 45 laterally offset by a distance L is offset on the same side by a distance L/ 2 (FIG- URE 12). The rack 41c disposed between two plates 45 offset in opposite directions to one another remains in its central position. The levers 49 therefore form differential mechanisms such that the movement of any rack is equal to half the algebraic sum of the movements of the two plates 45 on either side of such rack.

The tappets 44 move past electromagnets which can make the plates 45 follow three difference paths, depending upon the signals transmitted to the electromagnets.

In the diagram shown in FIGURE 13, lines 60, 61, 62 represent the three possible paths which can be followed by the ball 45 of a guide plate 45 and hence by the associated rack 41, according to the angular position which the actuating electromagnets, diagrammatically represented by the reference 47, have imparted to its tappet.

If two consecutive plates 45 both travel along the same path 61, the rack between them follows the curved path 63. If the front plate follows the straight path and the rear plate follows the curved path 61, the rack follows the path 64. If the front plate follows the curved path 61 and the rear plate follows the straight path 60, the rack follows the path 65. If the front plate follows the curved path 62 and the rear plate follows the curved path 61, the rack follows the path 66. If both plates follow the straight path 60, the rack follows the same path too.

By a permutation of these movements, the rack can be made to follow the other four paths 67-70.

Rack displacement is therefore proportional to the algebraic sum of the movements of the two plates on either side of it.

In FIGURE 13, the zone corresponding to engagement of the racks with the output wheel is bounded by the lines M and N, and, as will be apparent, the following cases occur in such zone;

Constant-speed movement of the rack in one direction or the other (curves 63 to 67);

Movement at increasing speed, starting from zero speed, in one direction of the other (curves 64 and 68);

Movement at decreasing speed, dropping finally to zero speed, in one direction or the other (curves and 69);

Reversal of direction in two different directions (curves 66 and 70);

No movement (line 60).

If the guide curves 61, 62, the spacing between the plates 45 and the engagement zone are chosen appropriately, the useful paths can, as in the example shown, he made to start from points R, S, T, spaced apart from one another by a constant interval corresponding to the halfpitch p of the rack tooth system. Consequently, if a number of consecutive racks travel along the paths 63 or 67, their movements can be made to correspond to a continuous rotation to either hand of the output wheel. Similarly, progressive stops or starts can be provided when a rack follows the paths 65 or 69 for stoppage or 64 and 68 for starting. Progressive movement reversals can be produced via the paths 66 or 70.

Referring to FIGURE 14, a curve 71 represents angular movement of the output wheel corresponding to the passage of a sequence of guide plates whose set-up positions are shown in relation to FIGURE 13. In FIGURE 14, the ordinate scale U represents the angle of output wheel rotation expressed as half-pitches of the output wheel tooth system. The abscissa scale V enumerates the consecutive racks, the reference at W indicating that particular curve of FIGURE 13 which the guide plate immediately following the particular rack concerned have followed. For instance, in phase 72 the originally stationary wheel experiences a gradually accelerating movement. In phase 7 3 such wheel rotates at a constant speed. In phase 74 the wheel is being gradually stopped. In phases 75 and 76 the direction of rotation is progressively reversed.

Consequently, the diiferential mechanisms between the racks make is possible to produce a continuous movement of the output wheel.

Other kinds of connecting mechanism can be used in variants. Referring to FIGURE 15, tappets 80 have lateral racks 81 meshing with toothed wheels 82 pivotably mounted on racks 83 co-operating with the output wheel. The same differential effect as provided by means of the levers 49 of the embodiment already described is obtained.

In other variants which are not shown, the connection between the drive elements and the actuating elements can take the form of flexible members such as cables, bands, tapes, chains or the like, or can be the result of the running of rollers disposed appropriately between the elements.

The device shown in FIGURES 16 to 22 comprises an input shaft running in two bearings 91 disposed in end plates 92, 93 secured to the ends of a tubular body 94. A rotor 95 whose periphery is formed with 12 longitudinal and even distributed grooves 96 is rigidly secured to the shaft 90. As can be seen in FIGURE 19, the rotor 95 is formed in two parts 95a, 95b which co-operate to bound an annular recess 97 receiving a ring 98 divided into two parts 98a, 98b (FIGURE 20). The ring 98 serves as a pivot or 12 plates 99 received one each in a groove 96 (FIGURES 16 and 17).

The plates 99 project at both ends of the rotor '95 and each have at their ends two teeth 100, 101 (FIGURES l6 and 21). The plates 99 have provision for limited pivoting (t); the pivot formed by the ring 98 extending through The tubular body 94 has two magnetic cores 102, 103 each comprising one central limb and two side limbs. Two energising windings 104, 105 are disposed on the side limbs of the core 102, and two windings 106, 107 are disposed on the side limbs of the core 103.

As the rotor 95 rotates, the plates 99 move past below the cores 102, 103, and the end faces 108 of the side limbs of the cores are so inclined as to produce a limited tilting movement of a plate moving past when one of the windings is energised. Consequently, when the plate 99a comes below the core 102 (FIGURE 16) it can either remain horizontal, if neither of the windings 104, 105 is energised, or pivot clockwise, if winding 104 :is energised, or pivot anticlockwise, if winding 105 is energised.

Depending upon whether the plate passing below an electromagnet remains horizontal or pivots anticlockwise or clockwise, the tooth at the right-hand end of the plate (FIGURE 16) is engaged in a central guide groove 109 in the end plate 92 or in side grooves 110, 111 disposed on either side of the central groove 109 (FIGURE 21). Having passed below the cores 102, 103 for selective direction into the end plate guide grooves, the plates 99 move past gearwheels 112, 113 rigidly secured to shafts 114, 115 mounted in the end plate 93 (FIGURES 16 and 18).

Over the angular range of rotor rotation corresponding to engagement of the tooth 101 of a plate 99 in a gearwheel, the side grooves 110, 111 are brought together into a single central groove so that the plate 99, if it was shifted when it passed below the core 102, is returned to the horizontal position during its engagement with the wheel 112, since the guide grooves 110, 111 converge in the corresponding angular zone. If the plate 99 remains horizontal when it passes below the core 102, the gearwheel 112 remains stationary, but if the plate 99 is tilted to the right or left below the core 102, the wheel 112 rotates by one tooth to one hand or the other.

The plates 99 are set up twice during each rotor rotation as they pass below each of the two cores 102, 103, and two output shafts 114, 115 are provided, which their respective gearwheels drive independently of one another in conformity with the energising programme transmitted to the windings of the corresponding core.

All that the electromagnets 102, 103 do is to control the tilting of the plates 99 before the latter engage with the gearwheels. The gearwheels 112, 113 are operated by the camming action of the guide grooves 110, 111 on the plates 99, and the input shaft 90 provides the output power.

FIGURE 22 is a diagrammatic view of the shape of the paths travelled by the tooth 101, the zone 116 corresponding to the passage of a plate 99 below a pole surface 108, whereas the zone 117 corresponds to engagement of the tooth 101 in the corresponding output wheel.

We claim:

1. A device for converting a continuous rotary movement into some other movement in dependence on electrical signals, including (a) support means,

(b) an input member comprising a rotor rotatably mounted in said support for receiving said continuous rotary movement,

() a toothed output member movably mounted in said support means,

(d) a plurality of operating members mounted on said rotor for motion relative to the rotor, each operating member being arranged during rotation of the rotor to mesh with the teeth of said output member during movement through a limited range of angular positions with respect to the rotary axis of the rotor,

(e) means controlling movement of the operating members with respect to the rotor and providing a plurality of permitted modes of movement of the operating members as they pass through said limited range of angular positions to impart corresponding movements to the output member,

(f) means for selecting one of said modes of movement for each operating member in accordance with said electrical signals.

2. The device of claim 1 wherein said means controlling movement of said operating members comprises cam means fixed to said support for co-operating with said operating members, said cam means being arranged to cause each operating member to move in a different mode for each of a plurality of permitted initial states of each operating member with respect to said rotor in a predetermined angular position of the operating member with respect to the rotary axis of said rotor and means comprising an electromagnet controlled by said electrical signals for determining said initial state of each operating member in said predetermined angular position.

3. The device of claim 2 wherein said cam means is arranged to return each operating member to a standard state after it has passed through said limited range of angles, said predetermined angular position being outside said limited range of angles and the electromagnet being arranged to move the operating member from said original state or allow it to remain in said original state as the operating member passes said predetermined angular position.

4. The device of claim 3 wherein said output member comprises a toothed gear member rotatable about an axis in a plane perpendicular to the rotary axis of said rotor and said operating members comprise toothed racks mounted for movement in directions parallel to the rotary axis of the rotor the teeth on said racks meshing with the teeth of said gear member over said limited range of angles whereby movement of the racks parallel to the rotary axis of the rotor, in said modes, imparts rotary movement to the gear member in corresponding modes.

5. The device of claim 4 wherein said racks are distributed at regular intervals around the rotor the width of said gear member and the spacing of said racks being such that the gear member is always in engagement with at least one of said racks.

6. The device of claim 4 wherein each operating mem-v ber includes a tappet articulated to said rack to permit limited pivotal movement of the tappet in a plane passing through the rotor axis, said states of the operating member corresponding to diiferent angular positions of the tappet with respect to the rack, the tappet in each said angular position engaging a different cam of said cam means or being out of engagement with said cam means, said electromagnet having at least one pole disposed at said predetermined angular position whereby said electrical signals supplied to the electromagnet cause the tappet to move into a desired angular position as it passes said pole.

7. The device of claim 6 wherein each said cam is formed so as to move the operating member parallel to the rotary axis of the rotor, in one direction, from the axial position it occupies in said original state, before its rack engages the gear member and then to return it to said axial position as it passes through said limited range of angles in engagement with said gear means, thereby to impart rotary movement to said gear mem- 8. The device of claim 7 wherein each tappet extends generally parallel to the axis of the rotor and is pivoted to its rack at a point intermediate its ends and intermediate axially extreme ends of the rotor, each tappet having cam engaging formations at axially extreme ends, the device including two electromagnets disposed adacent axially opposite ends of the rotor and having their poles in said predetermined angular positions adacent the tappets as the latter pass said poles, said cam means comprising a first and second cam groove located ad acent opposite ends of said rotor such that when one electromagnet is energised a tappet passing it is tilted so that one of said formations engages in one said cam groove, that when the other electromagnet is energised the tappet is tilted so that its other said formation engages in one said cam groove and when neither electromagnet is energised the tappet is not tilted and does not engage in either cam groove.

9. The device of claim 6 wherein each tappet and its associated rack are of thin sheet material, each tappet and its rack being slidably mounted in a longitudinally and radially extending groove in the rotor, the tappet being pivoted to the rack by a ball engaged in registering apertures in the tappet and rack, the ball projecting into longitudinally extending complementary grooves formed in the side walls of said slot.

10. The device as set forth in claim 9 wherein the tappets are in tension while being moved by said cam means while in engagement with the output member.

11. The device of claim 9 wherein the electromagnet comprises a pole surface which is inclined away from the tappets in the direction in which the latter moves past said pole surface.

12. The device of claim 11 in which each electromagnet has a core in the shape of a single helical convolution around the rotor axis and which terminates in pole surfaces substantially in alignment with each other and disposed in a plane passing through the rotor axis in said predetermined angular position.

13. The device of claim 1 wherein said operating members comprise a plurality of drive elements distributed at regular intervals around the axis of the rotor and the device comprises a plurality of actuating elements each disposed between two adjacent drive elements, and connecting means between each actuating element and the adjacent drive elements whereby the movement of each drive element is the result of movements imparted to at least said two adjacent actuating elements.

14. The device of claim 13 wherein said drive elements and said actuating elements are arranged alternately at intervals around the rotor.

15. The device of claim 13 wherein said connecting means form differential mechanism such that the movement of each drive element is proportional to the algebraic sum of the two actuating elements disposed around it.

16. The device of claim 13 wherein said connecting means comprises a lever pivoted to each drive member at its middle and connected at opposite ends to the adjacent actuating elements on either side of the drive element.

17. The device of claim 13 wherein said connecting means comprises a gearwheel rotatably mounted on each drive element and meshing with complementary tooth systems on the adjacent actuating elements on either side of the drive element.

18. The device of claim 1 in which the operating members are mounted on the rotor so as to pivot in a radial plane thereof and have at a terminal part at least one tooth to engage said toothed output member.

19. The device of claim 1 in which the operating members comprise plates disposed in longitudinally and radially extending slots in the rotor, the operating elements being pivoted for movement in a radial plane about a point in a central zone of the rotor, each operating member having teeth at axially extreme ends thereof, said output member comprising a toothed gear mounted adjacent one end of the rotor for rotation about an axis in a plane perpendicular to the rotor axis, and a plurality of cam guide means being provided on said support means at the other end of the rotor, one tooth of each operating member engaging said toothed gear and the other tooth engaging a selected one of said carn guide means during movement of the operating member through said limited range of angular positions, said cam guide means being selected in accordance with the tilt imparted to said operating member, prior to its entering said range, by means comprising an electromagnet arranged to receive said electrical signals.

20. The device of claim 19 in which the operating members are pivoted to a split ring received in an annular cavity in the rotor.

21. The device of claim 19 in which the electromagnet comprises a three-lim-bed core disposed in a radial plane of the rotor, the two side limbs terminating in pole faces on opposite sides of the plane of the pivotal connection of the operating members, an energising' winding on each said side limb, whereby energisation of one of said windings will tilt said operating members in one sense or the other as they pass the electromagnet.

References Cited UNITED STATES PATENTS 3,174,354 3/1965 Kuehnle 74-424.5 3,059,360 10/1962 Krauskopf 7484 X LEONARD H. GERIN, Primary Examiner US. Cl. X.R. 74-25, 84, 439

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