WO2015145201A1

WO2015145201A1 - Globo-conical cam device

Info

Publication number: WO2015145201A1
Application number: PCT/IB2014/060135
Authority: WO
Inventors: Gianbattista GIUSSANI; Gianfranco Colombo
Original assignee: Inman S.R.L.
Priority date: 2014-03-25
Filing date: 2014-03-25
Publication date: 2015-10-01

Abstract

Cam device comprising a driving rotor rotatable around a first rotation axis and provided with at least one first guide profile, and a respective at least rotating driven member. The driven member is at least swiveling around a second rotation axis perpendicular to the first rotation axis of the driving rotor. Such a driven member has at least one follower which, rotationally integral with such a driven member, engages a first guide profile of the driving rotor along a predefined path. Advantageously, such a path followed by the afore said at least one follower, substantially does not intersect a first plane comprising the first rotation axis of the driving rotor and being perpendicular to the second rotation axis of the at least rotating driven member, and it does not even intersect a second plane comprising the first rotation axis of the driving rotor and being parallel to the second rotation axis of the at least rotating driven member.

Description

"Globo-conical cam device"

FIELD OF THE INVENTION

The present invention concerns a cam device, and particularly a device of the type comprising a cam composed of a driving rotor usually having an approximately cylindrical shape, which is provided on its side surface with a guide profile for at least one respective follower, and of an at least rotating driven member provided with the afore said at least one follower and rotationally driven due to the engagement of such at least one follower with the guide profile of the driving rotor. KNOWN PREVIOUS ART

Substantially two kinds of cam of such a typology are known in the art.

A first typology of cam, known in the art as barrel cam, has a driving rotor of cylindrical shape provided with a guide profile obtained in its side surface, and an at least rotating driven member provided with one or more followers which engage such a guide profile, and wherein such followers substantially follow a path lying on, or intersecting, a plane that is perpendicular to the rotation axis of the driven member and is parallel to the rotation axis of the driving rotor. Practically, the followers of the at least rotating driven member are usually arranged in parallel to the rotation axis of the driven member.

Such a cam typology has an advantageous rotation gear ratio, because an appreciable rotation of the driving rotor is needed, and moreover such a driving rotor must have great size in order to achieve effectively usable rotations of the driven member. Moreover, the driven member must be placed in a position higher than the driving rotor, whereby the space under the same driven member is mostly filled by the driving rotor that, as mentioned, has great size. Therefore it is difficult to constrain, for example, a shaft or any other apparatus in a position lower than the driven member or, in general, to use such a space located underneath the afore said driven member.

In the art a different typology of cam is known as globoidal cam. Such a typology of cam has a driving rotor also having a cylindrical shape too and provided with a guide profile obtained in its side surface, and an at least rotating driven member provided with followers intended to engage the afore said guide profile of the driving rotor. The followers engage the guide profile along a path that substantially lies on, or intersects, a plane that is parallel to the rotation axis of the driving rotor and is further perpendicular to the rotation axis of the driven member. In other words, the followers are placed radially with respect to the rotation axis of the driven member when they are engaged with the afore said guide profile.

This solution, with respect to the so-called typology of barrel cam, allows to realize wide movements of the at least rotating driven member, with respect to little movements of the driving rotor. However, in the globoidal cam the driven member is placed laterally to the driving rotor, whereby the operative space underneath the followers is little, for example in order to arrange the additional controlling elements. It has to be noticed that such devices with tridimensional cam, both of barrel and globoidal type, are often and mainly used in mechanisms for changing tools in machine tools, for example those intended to carry out several machining by means of different tools/implements on a same semifinished product. In this case, the afore said at least rotating driven member could comprise a shaft for selectively move the tools, shaft that, in its turn, could be combined with other motion driving elements, for example additional cams usually rotationally constrained to the afore said driving rotor, which allow to force the same shaft to move differently in a controlled way, not only necessarily circularly.

In a similar application, the compactness of the cam device and its effectiveness in transmitting controlled motions to the at least rotationally driven member, are essential to guarantee an optimal operation of the mechanism for changing tools. Object of the present invention is to solve problems of the known art which have been just mentioned above.

Additional object of the present invention is to make a cam device having an effective gear ratio between the driving rotor and an at least rotating driven member, which allow to use as much as possible the operative space around such components. Again, another object of the present invention is to provide a cam device of the tridimensional type which is appreciably effective in transmitting the controlled circular motion to the at least rotating driven member. BRIEF DESCRIPTION OF THE INVENTION

The present invention achieves these and other objects by means of a device according to claim 1. Preferred aspects of the present invention are set forth in the respective dependent claims.

The cam device according to the present invention comprises a driving rotor rotatable around a first rotation axis and provided with at least one first guide profile, and a respective at least rotating driven member. The driven member is at least swiveling around a second rotation axis perpendicular to the first rotation axis of the driving rotor. Such a driven member has at least one follower which, rotationally integral with such a driven member, engages a first guide profile of the driving rotor along a predefined path. Advantageously, such a patch followed by the afore said at least one follower, substantially does not intersect a first plane comprising the first rotation axis of the driving rotor and is perpendicular to the second rotation axis of the at least rotating driven member, and it does not even intersect a second plane comprising the first rotation axis of the driving rotor and is parallel to the second rotation axis of the at least rotating driven member.

Thanks to the present invention, as it will be evident to the person skilled in the art, it is possible to employ operatively the unused or unusable space in devices known in the art, for example to insert additional controlling elements. Furthermore, the favorable gear ratio between the driving rotor and the at least rotating driven member allows to operate the driven member in spite of relatively little movements and size of the driving rotor.

It has to be noticed that with the term "path" it is herein intended, and in the following, the ideal line in space that the follower portion engaged with the afore said first guide profile substantially follows during the device operation, i.e. during the rotation of the driving rotor.

According to a particular aspect of the present invention, the driving rotor has a substantially cylindrical shape and the afore said rotation axis coincides with the geometrical axis of the driving rotor having a substantially cylindrical shape. Furthermore, the afore said guide profile is obtained on the side surface of the driving rotor having a substantially cylindrical shape. That is to say that, in other words, the cam device of the present invention is a tridimensional-cam device with a substantially cylindrical cam.

According to a further aspect of the present invention, the follower has an axis inclined with respect to both the afore said first and second planes.

Preferably, the follower has the rotation axis around the driven member and this axis is inclined as afore defined and incident to the rotation axis of the driving rotor. Such an inclination, referred to the first plane, is preferably comprised between 10° and 80°.

A preferred range is comprised between 20° and 60°.

Furthermore, preferred values of this inclination are about 25°.

As mentioned above, the present invention allows to define additional controlling elements for the driven member.

In particular, according to a particular aspect of the present invention, the driving rotor has a second guide profile, and a first arm is hinged to a fixed point, for example to the machine structure that comprises the device of the present invention, so that to rotate around an axis parallel to the first rotation axis of the driving rotor, although independently from the latter. The first arm has engaging means to engage the second guide profile of the driving rotor, and engaging means to engage the driven member.

Therefore, the first arm is subjected to a passive control of the driving rotor and it carries out an active control on the driven member.

According to an embodiment of the invention, the engaging means to engage the first arm to the at least rotating driven member, control a translation of the same driven member, typically in a direction parallel to the rotation axis itself.

However it is preferred that such a translation is not transmitted to either the followers. To achieve this, the at least rotating driven member can be composed of two concentric elements that can mutually translate, whereby a first swivel concentric element carries the followers and a second concentric element is translationally driven by the first arm.

Thanks to the present invention, it is further possible to provide for a second arm on the driving rotor, which operates similarly to the previously described first arm. In particular, the second arm can be rotationally controlled in a passive way by a third guide profile of the driving rotor, and then it can engage the at least rotating driven member, for example by driving the translation of a third concentric element that can be translated with respect to the two previously described concentric elements.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary and not limiting embodiments of the present invention are now illustrated with reference to attached figures, in which:

- figure 1 is a schematic view of a cam device according to the present invention;

- figure 2 is a perspective view of an embodiment of the cam device according to the present invention;

- figure 3 is a rear perspective view of figure 2;

- figure 4 is a top view of the device of the preceding figures; and

- figure 5 is a perspective view of a possible application of the cam device according to the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION

In figure 1 a cam device 1 according to the invention is schematized in a generic and simplified way. A particular embodiment is shown in Figures 2 and 3.

In particular, the herein illustrated cam device 1 comprises a driving rotor 2 that is rotatable around a first rotation axis Al (in figure 1 exiting from the sheet), and provided with a first guide profile 3 visible, for example, in figures 2 and 3. Apposite motor means, not shown, control the rotation of the driving rotor 2.

According to a preferred aspect of the present invention, such a driving rotor 2, also referring to figures 2, 3 and 4, has a substantially cylindrical shape with a geometrical axis coincident to the afore said first rotation axis Al and the first guide profile 3 is obtained along the side surface of such a driving rotor 2 having a substantially cylindrical shape. In other terms, the guide profile 3 extends substantially linear along the side surface of the rotor 2, which rotates around the first rotation axis Al.

It has to be noticed that, in embodiments of the present invention herein not illustrated, the driving rotor 2 can have any other shape, for example spherical or spherical in a sector, which allows to make the first guide profile 3 on a surface rotating around the afore said rotation axis A l .

An at least rotating driven member 4 has its own rotation axis A2, here also named as second rotation axis A2, substantially perpendicular to the first rotation axis Al of the driving rotor 2.

The driven member 4 has also one or more followers 5, and preferably a plurality of followers 5 shaped to engage, alternatively one to another, the guide profile 3.

Typically, such followers 5 are arranged along generatrices of a surface conical with respect to the driven member 4, and they are preferably arranged on a support 6 usually composed of a cylindrical crown wheel.

The followers 5, according to the rotation angle adopted by the support 6 with respect to the driving rotor 2, are shaped to engage the first guide profile 3 of the driving rotor 2 preferably one at a time and in a mutually exclusive way, or at most always preferably two at a time, with the possible remaining followers excluded. However it is not excluded that all followers 5 can engage contemporaneously with such a guide profile 3.

In the herein illustrated embodiment, the followers 5 have in turn a cylindrical shape having, according to a preferred but not exclusive aspect of the present invention, their own geometrical axis inclined with respect to both rotation axes Al and A2, respectively, of the driving rotor 2 and the driven member 4. The followers 5 can be made in one piece with the support 6, and then they can be completely integral with the latter, or else they can be made by means of cylindrical rollers rotatable around pins, or other radial elements, protruding from the same support 6.

It has to be observed that, in particular, the followers 5 are arranged in such a position to allow an operative use of a great portion of the space around the driving rotor 2 and the driven member 4.

To obtain this, each of the followers 5 engages the afore said first guide profile 3 of the driven member 2 along a path not intersecting a first plane PI, defined as the imaginary plane comprising the first rotation axis Al of the driving rotor 2 and also perpendicular to the second rotation axis A2 of the driven member 4, nor a second plane P2, which is defined as the imaginary plane comprising the first rotation axis Al of the driving rotor 2 and parallel to the second rotation axis A2 of the driven member 4.

As can be seen in figure 1, in case in which the second rotation axis A2 of the at least rotating driven member 4 is arranged vertically, then the planes PI and P2 are planes comprising the first rotation axis Al of the driving rotor 2 and arranged horizontally and vertically, respectively.

Therefore, each of the followers 5 remains outside of such planes PI, P2, that is the path they follow - or better, the path the portion of the follower 5 engaged with the afore said first guide profile 3, follows - is not substantially incident to these planes, for the whole rotation path around the second rotation axis A2 of the driven member 4.

It has to be observed that such a course (or path) followed by each of the followers 5 is then a circumference, or an arc of circumference, having such a second axis A2 as a center, and the law of motion each follower 5 follows along such a path is given by the shape of the first guide profile 3 with which the follower 5 engages. None of the points of such a circumference, or arc of circumference, belongs to any one of the afore said two planes PI , P2.

In figure 1 with a dashed line, for better clarity, two possible configurations of the followers 5.1, 5.2 are shown and do not satisfy such a requirement, and then they are not realized according to the present invention but, on the contrary, they are respectively typical of devices with globoidal cam and devices with barrel cam.

In particular a first follower 5.1, not realized according to the invention, is arranged in a position lateral to the driving rotor 2 on a supporting crown wheel 6.1 (only partially visible), and is tangent to the first plane PI for substantially its whole rotation path around a respective rotor, not shown.

Additionally a second follower 5.2, not realized according to the invention, is arranged above the driving rotor 2 on a supporting crown wheel 6.2 and intersects the plane P2 for part of its own course.

On the contrary, according to a particular aspect of the present invention, the followers 5 can have a development axis A2, i.e. that axis along which they are arranged with respect to the driven member 4, or the respective supporting crown wheel 6, and along which they engage with the first guide profile 3 inclined with respect to both panes P I , P2.

This inclination, herein shown as inclination a, is measured as projected on a plane simultaneously perpendicular to the axis Al (i.e. a plane parallel to the section of figure 1), when the followers are comprised between the rotation axis Al of the driven member 4 and the second plane P2.

Advantageously, such an inclination a is measured with respect to the first plane PI . Preferred values of such an a inclination are comprised between 10° and 80°. A preferred range of values for the a inclination is comprised between 20° and 60°, whereas a preferred value for the a inclination is about 25°.

Furthermore, according to a distinctive aspect of the present invention, the a inclination is such that the A3 axis is substantially directed so as to be incident to the rotation axis Al of the driving rotor, at least when the follower 5 is comprised between the rotation axis A2 of the driven member 4 and the second plane P2, or at least in the condition of most nearness of the follower 5 with respect to the second plane P2.

In other words, preferably the axis A3 of each follower 5, when the latter is engaged with the first guide profile 3 of the driving rotor 2, is incident not only to the afore said second rotation axis A2 of the driven member 4, but also to the afore said first rotation axis Al of the driving rotor 2.

A particular embodiment of the invention is shown in figures 2 and 3, wherein the same numerical references of figure 1 are used.

As mentioned, the driving rotor 2 has a substantially cylindrical shape, swiveling around the axis Al, and has a guide profile 3 for the followers 5 of the at least rotation driven member 4, arranged on the side surface of the cylinder.

The driven member 4 has, in the particular embodiment of the present invention shown in figures 2 and 3, a telescopic shape, and is composed of three concentric elements 4a, 4b, 4c which are substantially rod-shaped.

A first, more outer concentric element 4a carries the followers 5 through the afore said supporting crown wheel 6, integral therewith. Inside the first concentric element 4a, an intermediate concentric element 4b and an additional inner concentric element 4c are arranged, shaped and mutually coupled one to another and in conjunction with the first element 4a, i.e. the supporting crown wheel 6, and to slide freely one with respect to another in the direction of the axis A2.

Thereby the concentric elements 4a, 4b, 4c of the driven member 4 can mutually translate one with respect to another in the direction of the rotation axis A2.

Appropriate mechanisms can constrain one to another the concentric elements rotating around the axis A2. Embodiments are provided in which the three elements are free to rotate one with respect to another around the axis A2.

Two additional guide profiles, particularly a second and third guide profile 3 a and 3b, respectively, are arranged on the front and back bases of the cylinder composing the driving rotor 2.

A first arm 7a is constrained, for example, to a fixed point of an element not shown in figures, rotatably with respect to the driving rotor 2 around a rotation axis A2 substantially parallel to, or at most coincident with, the rotation axis Al of the driving rotor 2.

It has to be noticed that, in the embodiment herein illustrated, the first arm 7a is hinged at an axis A4 parallel to the same rotation axis Al. However, in embodiments of the present invention herein not shown, such a first arm 7a can be rotationally constrained to any device support, in case to the driving rotor 2 too, provided that such a constraint allows the rotation of the arm 7a around an axis A4 parallel or coincident to the afore rotation axis Al.

The first arm 7a has engaging means 8a to engage the second guide profile 3a, in order to cause a rotational movement of the first arm 7a around its own axis A4 as a response to a rotation of the driving rotor 2.

In particular, the engaging means 8a can be realized by a portion of the first arm 7a which has a projection, similarly to the followers 5 shown in figures, adapted to cooperate with the second guide profile 3 a.

Additional engaging means 9a connect operatively the first arm 7a to the third concentric element 4a, i.e. the inner concentric element of the driven member 4. In particular, the engaging means 9a are made through a projection 9a adapted to cooperate with a slot 4.1c integral with the inner concentric element 4c. The movement of the projection 9a, and in particular the rotation of the projection 9a around the rotation axis A4, caused by the cooperation between the engaging means 8a with the second guide profile 3a, causes the translation of the slot 4.1c in the direction of the rotation axis A2 of the driven member 4, and then a translation of the concentric element 4.1c with respect to the first concentric element 4a, and then to the supporting crown wheel 6 of the same driven member 4.

The device 1 can also have a second arm 7b.

In brief, also the second arm 7b is similarly constrained to the arm 7a with respect to the driving rotor 2 around an axis A5 parallel to the axis Al, or coincident with the latter, and it is provided with engaging means 8b to engage the third profile 3b of the driving rotor 2 and with engaging means 9b to engage a slot 4.1b of the intermediate concentric element 4b, so that to cause the translation thereof along the rotation axis A2 of the at least rotating driven member 4.

It has to be observed that, generally, also the afore said second arm 7b can be rotationally constrained to any support of the device 1 that, in an embodiment, can be the same driving rotor 2, provided that such a constraint allows the rotation of the second arm 7b around an axis A5 parallel or coincident with the afore said rotation axis Al of the driving rotor 2.

A similar cam device 1 is particularly suitable in a so-called device for changing tools (or implements), i.e. in a transferring manipulator adapted to transfer (and in case to rotate) an object between a first station and a second station. The cam device

1 described in figure 2 and in figure 3 allows, as a matter of fact, three different controls, i.e. a control of the rotation of the driven member 4 and the control of the vertical translation of the concentric elements 4b and 4c.

In general, it is anyway evident that, for similar and different applications too, on the driving rotor 2 a different number of arms 7a, 7b could be present, as well as these arms could be absent.

Consequently, it is possible to vary the number of concentric elements 4a, 4b, 4c of the at least rotating driven member, and at most also to provide for only one element, which is only swivel and integral with the supporting crown wheel 6 for the followers 5. In brief, during the operation of the device, the driving rotor 2 is rotated in a controlled way. Because of the cooperation among the guide profile 3 and the followers 5, the driven member 4 is rotationally moved around its own axis A2. In case there are one or more arms 7a, 7b, the engagement of the respective second and third guide profiles 3a, 3b of the driving rotor 2 with the engaging means 8a, 8b, causes the rotation of the arms 7a, 7b themselves, and the handling of the driven member 4. In the embodiment shown in figures, the arms 7a, 7b control the translation along the rotation axis A2 of the driven member 4 of the concentric elements 4b, 4c of the same driven member 4.

In case of use of a cam device 1 of the present invention in a mechanism for changing tools, such translations of the concentric elements 4b. 4c could control, for example through appropriate kinematic systems, the movement and/or the opening and closing of the gripping means, for example the clamps, to seize and release selectively the tool to be handled.

Figure 5 illustrates a possible application, quite exemplary, of the above described cam device 1 in a mechanism for changing tools.

In particular the driven member is constrained, by an appropriate kinematic system, to two supporting rods 12a, 12b aligned and diametrical with respect to the rotation axis A2 of the driven member 4, carrying at their ends some clamps 13a, 13b for reversibly seizing and restraining implements or tools provided with an appropriate shank shaped to engage with the afore said clamps 13a, 13b.

In particular in the mechanism schematized in figure 5, the controlled rotation of the driven member 4 imposed by the engagement of the followers 5 with the first guide profile 3 of the driving rotor 2, is transmitted to the afore said supporting rods 12 so that they can alternately carry out, with a first supporting rod, the displacement of a selected tool to an operative position and, at the same time, they can carry out, with the other supporting rod, the hold and then the respective release of a previously selected tool.

Furthermore, the different and controlled axial translation (along the axis A2) of the concentric elements 4b, 4c of the driven member 4 (thanks to the arms 7a, 7b and the respective cam profiles 3a, 3b), conveniently connected through kinematic systems known in the art to the clamps 13a, 13b, allows to control the insertion and extraction of the shanks of the tools from the clamps 13a, 13b and, in addition, to control a generic locking and unlocking apparatus of the same tool shanks with respect to the same clamps 13a, 13b.

In this way such a mechanism for changing tools, adjusted through the herein illustrated cam device 1, according to a preferred aspect of the present invention, is mechanically controlled by such a device 1 in all its steps of holding, blocking, exchanging, unfastening and releasing of the tool, without the need of using, for example, spring clamps which require the engagement, also with collisions and sliding, with the tool to carry out at least part of the above briefly listed operations.

Claims

1) Cam device (1) comprising a driving rotor (2) rotatable around a first rotation axis (Al) and provided with at least one first guide profile (3), and a driven member (4) at least rotating around a second rotation axis (A2) substantially perpendicular to the first rotation axis (Al) of said driving rotor (2), and provided with at least one follower (5) engaging said first guide profile (3), said at least one follower (5) being rotationally integral with said driven member (4), characterized in that said at least one follower (5) engages said at least one first guide profile (3) along a path substantially not intersecting a first plane (PI) comprising said first rotation axis (Al) of the driving rotor (2) and being perpendicular to said second rotation axis (A2) of said driven member (4), and further it substantially does not intersect a second plane (P2) comprising said first rotation axis (Al) of the driving rotor (2) and being parallel to said second rotation axis (A2) of said driven member (4).

2) Cam device according to claim 1, wherein said follower (5) has an axis (A3) inclined with respect to both said first and second planes (P 1 , P2).

3) Device according to claim 1 or 2, wherein said at least rotating driven member (4) has a plurality of followers (5).

4) Device according to claim 3, characterized in that each follower (5) of said plurality of followers engages said at least one guide profile (3) alternately to the other followers.

5) Device according to claim 2, 3 or 4, wherein said follower (5) has an axis (A3) inclined with respect to said first plane (PI), having an inclination comprised between 10° and 80°.

6) Device according to claim 5, wherein said inclination is comprised between 20° and 60°.

7) Device according to claim 6, wherein said inclination is substantially equal to 25°.

8) Device according to one of the preceding claims, wherein said driving rotor (2) has a second guide profile (3 a) and a first arm (7a) swiveling around an axis parallel or coincident to said first rotation axis (Al) of said driving rotor (2), said first arm having engaging means to engage said second guide profile of said driving rotor, and engaging means to engage said at least rotating driven member. 9) Device according to claim 8, wherein said driving rotor has a third guide profile (3b) and a second arm (7b) swiveling around an axis parallel or coincident to said first rotation axis of said driving rotor, said second arm having engaging means to engage said third guide profile of said driving rotor, and engaging means to engage said at least rotating driven member.

10) Device according to claim 8 or 9, wherein said at least rotating driven member (4) has at least two concentric elements (4a, 4b), at least one of said concentric elements being operatively constrained to at least one of said first and second arms.

11) Device according to any one of the preceding claims, characterized in that said driving rotor (2) has a substantially cylindrical shape, and said first rotation axis coincides with the geometrical axis of said driving rotor having a substantially cylindrical shape and said at least one first guide profile is obtained on the side surface of said driving rotor having a substantially cylindrical shape.