"Device for moving components, particularly in optical systems"

The present invention relates to a device for moving components, particularly in optical systems, for example telescopes, microscopes, binoculars, cameras, video cameras, endoscopes, parabolic antennas, eyepieces, either individual or paired, but also generally in mechanical systems and devices. With particular reference to the optical field, this moving devices, which are also called the "focusers", are particularly used for adjusting the relative distance and/or inclination between two optical components, such as lenses, mirrors or filters for example to the purpose of focusing an optical system directed on a particular object or in order to adjust the shape of an optical component, such as a parabolic antenna provided with a number of segments that can be moved relative to each other.

Knob focusers are known, in which a threaded bar is connected, on the one side, to an optical component and on the other side, to a ring nut that is pivotally associated with the support frame of the optical system, such that when the ring nut is rotated relative to the threaded bar, the distance between the optical component and the ring nut can be adjusted.

The prior art knob focusers have the drawback that a very fine thread is required for obtaining a very fine adjustment. However, the provision of very fine threads is difficult and very expensive. Furthermore, very fine threads have high relative tolerances, i.e. the pitch change relative to the average value (or design value) of the thread pitch increases as the pitch decreases. This raises particular problems in those optical systems with automatic activation devices, such as motor-driven, since they require a univocal link between the rotation angle of the ring nut and the feed value of the threaded bar.

Since fine threads are more easily manufactured when they have small diameters, the area of mutual engagement between the ring nut and threaded bar is usually very restricted, both diametrically and longitudinally. This entails a considerable reduction in the lateral stiffness of the threaded bar, which tends to cause the tilting of the optical component before translating the same. This tilting of the particular optical component, such as a mirror or a lens, results in image shifting and focusing delay when the optical component is moved towards and away from either the support frame or another optical component. Said prejudicial effects are further enhanced when the maximum free length of the threaded bar, and accordingly the usage and adjustment range of the optical system, e.g.

a telescope, is increased.

Accordingly, the object of the present invention is to provide a device for moving components, particularly in optical systems but also in mechanical systems and devices in general, having such characteristics as to overcome the drawbacks cited with reference to the prior art.

This object is achieved by means of a moving device for a component in a system, such as an optical system, by means of a threaded bar associated with the component, comprising:

- a fine adjustment knob with a central hole provided with a first inner thread suitable to engage a corresponding first outer thread of the threaded bar such that a rotation of the fine adjustment knob relative to the threaded bar will cause a first translational movement of the threaded bar relative to the fine adjustment knob along a reference axis, connection means suitable to connect the fine adjustment knob to a support frame of the optical system in a pivotal manner about the reference axis, wherein the connection means comprise a second inner thread suitable to engage a corresponding second outer thread of the fine adjustment knob such that said rotation of the fine adjustment knob will cause a second translational movement of the fine adjustment knob relative

to the support frame along said reference axis and the overall translational movement of the threaded bar relative to the support frame is the sum of said first and second translational movements. In order to better understand the invention and appreciate the advantages thereof, several embodiments thereof will be described below by way of non-limiting examples, with reference to the annexed drawings, in which:

- Fig. 1 is a sectional view of a device according to a first embodiment of the invention;

- Fig. 2 is a sectional view of a device according to a second embodiment of the invention;

- Fig. 3 is a sectional view of a device according to a third embodiment of the invention; - Fig. 4 is a sectional view of a device according to a fourth embodiment of the invention;

- Fig. 5 is a partially sectional view of a device according to a fifth embodiment of the invention;

- Fig. 6 is a detail of an optical system on which the device according to the invention can be assembled.

With reference to the figures, a moving device is overall indicated with numeral 1. The device 1 is to adjust the position of an optical component 2, such as a mirror or a lens, in an optical system 3 through a threaded bar 4 associated with the optical component 2.

The device 1 comprises a fine adjustment knob 5 with a central hole 6 provided with a first inner thread 7 suitable to engage a corresponding first outer thread 7' of the threaded bar such that a rotation of the fine adjustment knob 5 relative to the threaded bar 4 will cause a first translational movement of the threaded bar 4 relative to the fine adjustment knob 5 along a reference axis R. The device 1 further comprises connection means for connecting the fine adjustment knob 5 to a support frame 8 of the optical system 3 in a pivotal manner about the reference axis R.

According to a first embodiment such as shown in Fig. 1, the connection means comprise a tubular member 9 that can be integrally rotatably fixed to the support frame 8 (the term "integrally rotatably fixed" means that relative rotation between the fixed parts is prevented) , wherein the tubular member 9 defines a second inner thread 10 suitable to engage a corresponding second outer thread 10' of the fine adjustment knob 5. Thereby, the rotation of the fine adjustment knob 5 will cause a second translational movement of the fine adjustment knob 5 relative to the tubular member 9 and relative to the support frame 8 along the reference axis R. Consequently, the fine adjustment knob 5 provides a differential screw and the overall translational movement of the threaded bar 4 relative to

the support frame 8 is the sum of the first and second translational movements.

In the present disclosure, by "sum" is meant the algebraic sum of the absolute values of the movements or more generally the tensorial or vectorial sum of the movements, considering the direction, way of direction and absolute value of the respective translational movement.

When the first thread 7, 7' matches the second thread 10, 10', the absolute value of the overall movement is equal to the difference between the absolute values of the first and second translational movements. A very fine adjustment can be thus obtained by two coarse threads provided that they have a very small pitch difference. The threaded bar is advantageously rotatably locked by means of a suitable connection member 11 that integrally rotatably connects the threaded bar 4 to the optical component 2.

In accordance with a second embodiment, such as shown in Fig. 2, the tubular member 9 can be pivotally connected to the support frame 8 on the reference axis R, thereby providing a tubular coarse adjustment knob 9' that defines a central hole 12 forming said second inner thread 10. The pivotal connection of the coarse adjustment knob 9' to the support frame 8 is advantageously provided by means of an annular clamp lid 13 by interposing one or more Belleville springs 14.

In order to ensure a univocal operation of the device 1, locking means are provided which are suitable to lock the rotation of the fine adjustment knob 5 relative to the coarse adjustment knob 9' when the coarse adjustment knob 9' is rotated about the reference axis R. Whereby, when the coarse adjustment knob 9' is rotated, the fine 5 and coarse 9' adjustment knobs will rotate together and cause only the first translational movement of the threaded bar relative to the fine adjustment knob 5. The fine adjustment knob 5 does not translate relative to the coarse adjustment knob 9' and the overall translational movement of the threaded bar 4 relative to the support frame 8 is thus only the first translational movement.

Consequently, by rotating the fine adjustment knob 5, the first 7, 7' and second 10, 10' threads are operative, and the differential screw effect suitable for fine adjustment is obtained. On the contrary, by rotating the coarse adjustment knob 9' , only the first thread 7, 7' is operative, which is suitable to provide a quick feeding of the threaded bar 4 and thus a coarse adjustment of the position of the optical component 2.

According to a further embodiment, such as shown in Fig. 3 and 4, the fine adjustment knob 5 comprises two or more tubular sub screws 15, 16 that can be screwed on each other to form said fine adjustment knob 5.

An inner sub screw 15 of the sub screws 15, 16 forms the first inner thread 7 of the fine adjustment knob 5 and a third outer thread 17' engaging a corresponding third inner thread 17 of the radially externally adjacent sub screw 16. An outer sub screw 16 of the sub screws 15, 16 forms both the second outer thread 10' of the fine adjustment knob 5 and a third inner thread 17 that engages a corresponding third outer thread 17' of the radially internally adjacent sub screw. Any further sub screws positioned between the outer sub screw and the inner sub screw are also screwed on each other. The number of sub screws is limited by the radial thickness available for the fine adjustment knob 5 and is selected according to the desired adjustment speed number. Thereby, a rotation of one of the at least two sub screws 15, 16 (hereinafter called the actuated sub screw 15) relative to the radially externally adjacent sub screw 16 causes a third translational movement of the actuated sub screw 15 relative to the radially externally adjacent sub screw 16. To ensure the univocal operation of the device 1, this embodiment also provides locking means acting such that, when the actuated sub screw 15 is rotated, the rotation of said actuated sub screw 15 relative to the radially externally adjacent sub screw 16 and the rotation of the inner sub screw 15 (which, in this instance, is identical

to the actuated sub screw 15) relative to the threaded bar 4 are only allowed. Thereby, the inner sub screw 15 always rotates together with the actuated sub screw and the overall movement of the threaded bar 4 relative to the support frame 8 is the sum of the first and third translational movements.

The embodiment shown in Fig. 3 and 4 provides only two sub screws and precisely the outer 16 and inner 15 sub screws, which are screwed on each other by means of said third thread 17, 17' to form the fine adjustment knob 5.

A rotation of the inner sub screw 15 relative to the outer sub screw 16 thus causes said third translational movement of the actuated sub screw, i.e. the inner sub screw 15, relative to the radially externally adjacent one, i.e. the outer sub screw 16.

Consequently, when the inner sub screw 15 is rotated, the locking means only allow the rotation of the inner sub screw 15 relative to the outer sub screw 16 and the rotation of the inner sub screw 15 relative to the threaded bar 4, such that the overall movement of the threaded bar 4 relative to the support frame 8 is the sum of said first and third translational movements. The inner sub screw 15 thus acts as a differential screw, by providing a third adjustment (such as very fine) speed in addition to the first adjustment (coarse) speed being produced by the

rotation of the coarse adjustment knob 9' and the second adjustment (fine) speed being produced by the fine adjustment knob (which is obtained by rotating the outer sub screw 16 thereof) . In accordance with an embodiment, the first thread 7, 7' matches the second thread 10, 10', such that, when the fine adjustment knob 5 is rotated, the first translational movement and the second translational movement are opposed and the absolute value of the overall movement of the threaded bar 4 relative to the support frame 8 is the difference between the absolute values of the first and second movements.

Advantageously, the first thread 7, 7' matches the second thread or threads 17, 17' , such that, when the sub screw 15 is rotated, the first translational movement and the third translational movement are opposed and the absolute value of the overall movement of the threaded bar 4 relative to the support frame 8 is the difference between the absolute values of the first and third movements. To the purpose of ensuring a translational movement of the threaded bar along the reference axis R without transversal or deviating movements, in all the embodiments such as shown in the Figures, the coarse and fine adjustment knobs are concentric relative to the reference axis (R) .

The locking means described above are suitable to provide permanent resistances against the relative rotation between the radially adjacent screws of the device 1, and particularly: - between the threaded bar 4 and the fine adjustment knob 5, i.e. resistance against the relative rotation in the first thread 7, 7' ;

- between the fine adjustment knob 5 and the coarse adjustment knob 9', i.e. resistance against the relative rotation in the second thread 10, 10' ;

- where provided, between each pair of sub screws 15, 16 of the fine adjustment knob 5, i.e. resistance against the relative rotation in the third thread 17, 17' .

Advantageously, the resistance against the relative rotation in the first thread 7, 7' is lower than that in the second thread 10, 10' and/or the resistance against the relative rotation in the third thread 17, 17' is lower than that in the second thread 10, 10' and/or the resistance against the relative rotation in the first thread 7, 7' is lower than that in the third thread 17,

17' .

In accordance with an embodiment, the locking means are friction means, which are advantageously provided by the various frictional torques that are formed in the various threads 7, 7' and 10, 10' and 17, 17' .

According to the preferred embodiment, the contact surfaces in the thread radially decrease from the radially outermost thread 10, 10' to the radially innermost one 7, 7' . To cause the fine adjustment knob 5 to rotate without rotatably driving the coarse adjustment knob 9', the locking means also comprise means for providing a permanent resistance against the relative rotation between the coarse adjustment knob 9' and the support frame 8, preferably elastic clamping means, such as one or more Belleville springs 14 that provide a frictional torque resisting the rotation of the coarse adjustment knob 9' relative to the support frame 8 which is greater than the torque resisting the rotation in said second thread 10, 10' . In accordance with a further embodiment such as shown in Fig. 5, the device 1 includes said threaded bar 4, which can be pivotally connected to the optical component 2 about the reference axis R and the locking means comprise further friction means suitable to provide a torque resisting the rotation of the threaded bar 4 about the reference axis R, such that the threaded bar 4 cannot be rotatably driven by the fine adjustment knob 5 or the inner sub screw 15 thereof.

Advantageously, an end 18 of the threaded bar 4 comprises a friction portion 19, which has preferably the

shape of a cone or truncated cone and is suitable to frictionally engage a corresponding seat being associated to the optical component 2.

Consequently, when the threaded bar 4 is rotated, the rotation of the fine adjustment knob 5 relative to the support frame 8 is prevented such that the rotation of the threaded bar 4 causes said first translational movement of the threaded bar 4 relative to the fine adjustment knob 5 and the overall translational movement of the threaded bar 4 relative to the support frame 8 is this first translational movement.

According to an embodiment, the pitch of the first thread 7, 7' matches and is greater than the pitch of the second thread 10, 10', such that the rotation of the fine adjustment knob 5 entails a fine adjustment translational movement of the threaded bar 4 relative to the support frame 8 and the rotation of the coarse adjustment knob 9' entails a coarse adjustment translational movement of the threaded bar 4 relative to the support frame 8. Advantageously, the pitch of the third thread 17, 17' matches and is greater than the pitch of the second thread 10, 10' and the pitch of the third thread 17, 17' matches and is lower than the pitch of the first thread 7, 7' such that the rotation of the actuated sub screw 15 entails an overall adjustment translational movement of the threaded

bar 4 relative to the support frame 8 which is finer than that obtained by rotating the whole fine adjustment knob 5

(i.e. the outer sub screw 16), which movement is, in turn, finer than the overall movement obtained by rotating the coarse adjustment knob 9' .

In accordance with a further embodiment, the fine adjustment knob 5 and/or the coarse adjustment knob 9' and/or the sub screws 15, 16 and/or the threaded bar 4 comprise respective handle portions for manual rotation or actuating portions for rotation by means of suitable actuating means, such as belt actuating means or gearings, which are in turn actuated by electric motors.

Advantageously, the handle portions and/or the actuating portions provide levers having a length proportional to the resistance against rotation of the corresponding screw such that all the adjustment screws 5, 9', 15, 16 can be rotated by means of the same force acting on said screw.

Possible automatic actuating means are for example rotary or linear motors or hydraulic jacks which are functionally connected with the adjustment knobs of the device 1.

In accordance with a further embodiment, the device 1 comprises sensor means, such as a digital thermometer suitable to detect values of temperature within the

optical system 3 and a control unit suitable to control the actuating means of the adjustment knobs based on the temperature values detected, such that the thermal expansion in the optical system can be balanced automatically.

The device 1 according to the present invention can be used both as equipment suitable to replace for example a one-knob focuser in a telescope and as an integrating part of optical systems requiring a fine adjustment of the location and/or orientation of optical components. These optical systems include, for example telescopes, microscopes, binoculars, cameras, video cameras, endoscopes, individual and paired eyepieces.

The device 1 according to the present invention has a number of advantages. Due to the differential screw operation, it allows adjustments in the order of micron fractions by means of threads with very less fine pitches than the prior art, and thus at a lower cost.

The device further allows multiple-pitch and multiple- speed adjustment, i.e. a quick feeding of the threaded bar by rotating the coarse adjustment knob and a subsequent fine adjustment by rotating the fine adjustment knob , for example along the final tract of a telescope focusing movement. This entails a considerable increase in the adjustment speed compared with the prior art optical

systems .

Due to the telescopic movement of the tubular adjustment knobs being screwed on each other, the threaded bar is laterally stabilized thereby resulting in almost the total absence of tilting in the optical components.

The moving device 1 described so far can be advantageously used also for the mechanical adjustment of the location of a whole optical system, e.g. a precision levelling system for theodolites and similar optical or laser-optical measurement, levelling and triangulation devices. The device 1 can be further advantageously used as a device for deforming complex optical components for correcting, either manually or automatically, the optical distortions thereof. For example by suitable sensors which supply a control unit with environmental or geometrical parameters identifying the optical distortion of the optical component, which control unit governs the moving device 1 based on the parameters detected.

As already explained above, while a moving device for an optical component in an optical system has been described by way of example, the invention also relates more generally to devices for moving and positioning mechanical components in mechanical systems in the fields of tool machine automation, precision positioning devices, such as for supporting a measurement device. The moving and

positioning device is not only limited to the function of translational movements and positioning but can be also advantageously used for taking and maintaining a determined position also under external loads and/or for transmitting and applying a determined force to an object. The device according to the invention can be thus advantageously implemented in valves, linear actuators, bearing and/or mould pullers for heavy loads, compensators of expansions due to thermal and mechanical stress, jacks, high-precision hoisting devices and controlled traction devices, as well as measurement equipment requiring adjustment in the relative position between at least two mechanical components. In accordance with an embodiment, one or more or all the threads are high-pitch, multi-start screw threads, such that a considerable increase in the pitch is obtained following a coarse adjustment or movement, at the same precision or resolution of the fine adjustment or movement depending only on the pitch difference between two multi-start screw threads, respectively. In this way, pitch ratios of coarse to fine movement can be obtained which exceed a value of 1000.

In accordance with a further embodiment, the device comprises biasing means, such as a return spring, which are associated with the device such as to axially bias the threads against each other for the same to be permanently

held in a well defined mutual abutment condition. This advantageously obviates to the occurrence of movements due to the backlash, which might otherwise exceed the order of magnitude of fine adjustment. Further embodiments provide that the locking means such as described above comprise one or more lag screws and/or inserts or threadlock substances. Alternatively, the shape of the threads is selected such that the threads have different friction values for providing said locking means. Obviously, to the device according to the present invention, those skilled in the art, aiming at satisfying contingent and specific requirements, may carry out a number of modifications and variations, all being however contemplated within the scope of protection of the invention, such as defined in the annexed claims.