WO2008049862A1

WO2008049862A1 - System for dimensional and form deviation checking with inductive charge device

Info

Publication number: WO2008049862A1
Application number: PCT/EP2007/061421
Authority: WO
Inventors: Federico Nonni; Guido Golinelli; Arnaldo Orsi
Original assignee: Marposs Societa' Per Azioni
Priority date: 2006-10-27
Filing date: 2007-10-24
Publication date: 2008-05-02
Also published as: ITBO20060746A1

Abstract

A checking system includes a gauge (1) with movable feelers, a position transducer adapted to provide electrical signals representative of displacements of the feelers, a wireless transmission system for transmitting the electrical signals and a battery electrically connected to the position transducer and to the wireless transmission system. An inductive charge device for contactless charging the battery includes a stator (20) with primary windings and secondary windings in the gauge (1). The charge device further includes a quick coupling/uncoupling mechanism (40) between the gauge and the stator, comprising a coupling element (31) and a matching element (6) adapted to mutually cooperate.

Description

DESCRIPTION

«SYSTEM FOR DIMENSIONAL AND FORM DEVIATION CHECKING WITH INDUCTIVE CHARGE DEVICE»

Technical Field

The present invention relates to a system for dimensional and/or form deviation checking of mechanical pieces with a gauge including at least one measuring armset with at least one feeler adapted to contact the mechanical piece to be checked, at least one transducer adapted to provide electrical signals representative of displacements of the at least one feeler, a wireless transmission system for transmitting the electrical signals, and at least one accumulator adapted to feed the at least one transducer and the wireless transmission system; and a contactless charge device adapted to charge the at least one accumulator and including a stator with primary windings, and secondary windings connected to the gauge and electrically coupled to the at least one accumulator, the primary and secondary windings realizing an inductive coupling.

Background Art

There are known checking systems including, for example, gauges called "plug gauges" or "snap gauges" for dimensional and form deviation checking of mechanical pieces . U.S. Patent US-A-4348814 discloses examples of such plug gauges, wherein a measuring armset connected to a support includes two feelers fixed to movable arms, for contacting the surface of a hole to be checked at diametrical opposite positions. A transducer detects mutual displacements between the movable arms and provides, through wires of a cable, electrical signals indicative of the mutual position of the feelers to external processing and display devices. The known plug gauges can be manually operated and tipically include a support and protection structure having a handle with an external surface that acts as handgrip for being used by an operator, and a probe comprising one or more measuring cells with one or more transducers in order to detect the workpiece dimensions. Such transducers are electrically fed by means of electrical cables steadily coupled to the gauge. There are also known wireless gauges, wherein signals representative of the dimension to be checked and generated by one or more transducers are wirelessly transmitted to external processing and display units, by means of transmission systems including electronic components located in the handle. Such wireless gauges are fed by batteries, normally housed in the handle, that provide current to the transducers and to the electrical/electronic components of the transmission system through an electrical circuit including a certain number of electrical contacts. Wireless gauges generally feature more ease of handling and more flexibility of employment than cable gauges, but provides the disadvantage of requiring the replacing and/or recharging of batteries whenever the latter discharge. There are known different devices for the battery charge: the batteries can be charged (or recharged) directly inside the plug gauge, or, on the contrary, can be disassembled and separately recharged on appropriated charge devices. Obviously, charging the batteries while in seat inside the plug gauge is more convenient and can be performed equipping in advance the plug gauges with appropriate electrical contacts, for example holes for pins or contact slots, intended to be coupled to associated contacts of an external power supply. This solution is quite simple and not expensive, but provides a disadvantage: the electrical contacts are exposed to the external environment and thus they can get dirty or wet, causing more or less serious malfunctions and dangers for the operator. In the prior art there are also known charge devices of inductive type that do not have exposed contacts so as to ensure operation reliability and safety for the operator. Figure 1 schematically shows a checking system of this type including a gauge, for example a plug gauge, for checking the diameter of a hole H, including a measuring armset with arms A movable about fulcra F, and feelers S fixed to the arms A that contact the surface of the hole H. A transducer L provides electrical signals responsive to the mutual position of the feelers S to a transmission unit T including for example an antenna that in turn wirelessly transmits the signals to a processing and display unit U. A battery B feeds both the transducer L and the transmission unit T. When necessary, the battery B is charged by approaching the gauge to an external power supply unit including an oscillator O, through an inductive coupling I with primary and secondary windings.

In the known inductive charge systems, the plug gauge is laid on a charge base, or stator, until the charge is complete. The correct position of the gauge on the stator is generally defined by bearing surfaces. Possible accidental displacements between the parts or an inaccurate bearing can interfere with a correct charge. Moreover, as the plug gauge is normally operated in workshop environment, during the charge the plug gauge laying on the charge base can be subjected to impacts and/or external stresses so that the gauge could fall and uncouple from the charge base, getting damaged and interrupting the charge process .

Disclosure of the invention

Object of the present invention is to provide a dimensional checking system with an inductive charge device that enables to overcome the disadvantages of known systems.

This and other objects are achieved by a dimensional checking system according to claim 1. A checking system according to the present invention provides both improved standards of performance in terms of mechanical and electrical reliability and low production costs at the same time. A system for dimensional and/or form deviation checking of mechanical pieces includes a gauge comprising at least one measuring armset with at least one feeler adapted to contact the mechanical piece to be checked, at least one transducer adapted to provide electrical signals representative of displacements of said at least one feeler, a wireless transmission system for transmitting the electrical signals, and at least one accumulator adapted to feed said at least one transducer and said wireless transmission system. The system further includes a contactless charge device adapted to charge said at least one accumulator and comprising a stator with primary windings, and secondary windings connected to the gauge and electrically coupled to said at least one accumulator, said primary and secondary windings realizing an inductive coupling; and a quick coupling/uncoupling mechanism between the stator and the gauge.

In a first preferred embodiment of the system according to the present invention, the quick coupling/uncoupling mechanism between the stator and the gauge is achieved by a threaded coupling between a female element connected to the stator (or to the gauge) and a male element connected to the gauge (or to the stator) . Therefore, the gauge is screwed into the stator so as to realize a mechanical, and thus electrical, connection which is stable and convenient at the same time.

In a second preferred embodiment of the present invention, the quick coupling/uncoupling mechanism between the gauge and the stator is achieved by a bayonet coupling, wherein each of the two components intended for coupling each other can be indifferently connected, as in the previous embodiment, either to the gauge or to the stator. Even thought the stability of the mechanical connection can be compared to the stability achieved by the first preferred embodiment, this second preferred embodiment provides the advantage of enabling the coupling/uncoupling of the gauge to the stator in an even quicker way. In a third preferred embodiment of the present invention, the quick coupling/uncoupling mechanism between the gauge and the stator includes a coupling element connected to the stator (or to the gauge) which can be coupled by pressure to an appropriate matching element connected to the gauge (or to the stator) , independently of angular references about a longitudinal axis of the gauge, that are necessary, on the contrary, for connecting the stator and the gauge of the inductive charge system according to the first and second preferred embodiment of the present invention.

Brief Description of the Drawings

The invention is now described with reference to the enclosed sheets of drawings, given by way of non limiting example, wherein: figure 1 is a functional diagram of a checking system with a known inductive charge device; figure 2 is a perspective view of a plug gauge of a checking system according to the present invention; figure 3 is a perspective view of a stator of a checking system according to the present invention; figure 4 is an exploded view of a checking system according to the present invention; and figure 5 is a partial and enlarged perspective view of the checking system of figure 4, according to a different point of view, with some details shown in cross-sectional view .

Figure 2 shows a multiple plug gauge 1 for manually checking internal diametral dimensions of holes, with wireless transmission of measuring signals. The plug gauge

1 includes a support and protection structure with a handle

2 which defines a longitudinal axis of the plug gauge 1 and is shaped in such a way that a central portion 3 of the handle 2 has a reduced diameter with respect to a first 4 and a second 5 end portions. The central portion 3 has an ergonomic shape to enable an easy and safe manual use of the gauge. At the first end portion 4, inside the handle 2 and not visible in the drawings, there are located secondary windings for inductive charging one or more accumulators, for example one or more rechargeable batteries, located inside the handle 2 and not visible in the drawings, too. The batteries feed known electrical/electronic devices of the plug gauge housed inside the handle 2 and not visible in figure 2 that acquire, process and transmit electrical signals representative of the checked dimensions. Such electrical/electronic devices can be, for example, one or more inductive position transducers for providing signals representative of the position of the feelers, circuits for conditioning the previous signals and wireless transmission systems with an antenna. A matching element, in particular a matching ring 6, is connected to the first end portion 4 and has an external matching surface 13 with a convex and chamfered rotation symmetry shape protruding with respect to the first end portion 4. The handle 2 further includes a push-button group 12 for controlling the plug gauge 1, i.e. for enabling an operator to manually power on, switch off, and select other required functions of the gauge, and a mechanical interface element 16 for connecting a known measuring probe 7 including a centering nosepiece 8 with holes 9 that enables feelers, not shown in the figure, to pass.

The centering nosepiece 8 houses measuring armsets of a known type, not visible in figure 2 but substantially similar to what is schematically show in figure 1, with movable arms that carry the feelers for contacting the workpiece to be checked and an inductive position transducer connected to the movable arms. The transducers, by detecting the mutual displacements of the arms, provide in a known way, electrical measuring signals representative of the dimension to be checked.

Figure 3 shows a stator 20 of a contactless charge device, in particular of inductive type, which includes an external casing 21 with a handgrip 22 for manual use by an operator, and a cylindrical body 24. To the handgrip 22 there is coupled a guide and protection element 23 for an electrical cable, not shown in the figure, that feeds - through an alternating current power supply - primary windings, not shown in the figure, located inside the stator 20 at the cylindrical body 24. Moreover, inside the cylindrical body 24 there are positioned electrical/electronic devices that are known and thus not illustrated, for managing the power supply of the primary windings.

A first part 30 of a quick coupling/uncoupling mechanism 40, is connected to the stator 20. Figures 4 and 5 show in detail the quick coupling/uncoupling mechanism 40 that advantageously includes a mechanical safety device with a protection and locking element, or retaining element 25 that is substantially hollow cylindrically shaped and comprises a first 49 and a second 52 internal narrowing with internal surfaces. The retaining element 25 further includes seats, more specifically transversal threaded holes 28 for stop elements, e.g. screws 26, and constraining surfaces, in particular defined by slits 29 intended for engaging constraining elements, such as screws 27 that are stationary with respect to the cylindrical body 24. The screws 27 housed in the slits 29 define an angular arrangement of the retaining element and keeps such arrangement, by preventing mutual rotations about the longitudinal axis of the plug gauge 1 between retaining element 25 and cylindrical body 24. The quick coupling/uncoupling mechanism 40 between the plug gauge 1 of figure 2 and the stator 20 of figure 3 includes, in addition to the first part 30, a second part 50 connected to the gauge 1. The first part 30 comprises a coupling element 31, a bearing element 34, and advantageously the mechanical safety device with a coil spring 35, in addition to the retaining element 25. The second part 50 of the coupling mechanism 40 includes the matching ring 6 that is coupled to the plug gauge 1 by means of longitudinal screws not visible in figure 4 and not shown in figure 5 for the sake of simplicity and clarity. The coupling element 31, advantageously made of hardened steel, has a substantially plane annular portion with an external rim 37. Coupling plates 32 having reduced thickness areas or preferential elastic deformation areas defining fulcra 39 are circularly arranged along such external rim 37, being alternated with bearings portions 36, substantially arranged on a cylindrical surface. Each coupling plate 32 has at its free end a tooth 33 which is shaped in such a way that can be coupled to the matching ring 6. The fulcra 39 are located at the external rim 37 so that each coupling plate 32, and thus the associated tooth 33, can rotate about a direction tangent to such external rim 37. The bearing portions 36 are T-shaped with transversal threaded holes 38 and longitudinal threaded holes 41, and cooperate with the matching ring 6, so achieving centering of the stator 20 with respect to the gauge 1.

The bearing element 34 is hollow cylindrically shaped with a discontinued lateral wall 44 wherein transversal threaded holes 45 are defined, and includes an external rim 46 with a lower abutment surface 47 and an upper abutment surface 48.

The coupling element 31 is mounted inside the bearing element 34 in such a way that the transversal threaded holes 38 of the bearing portions 36 are coaxial to the transversal threaded holes 45 of the lateral wall 44. The constraining screws 27 and clamping screws 51 are screwed into the transversal holes 38 and 45, and mutually lock the coupling element 31 and the bearing element 34. Screws 42 located in the longitudinal holes 41 of the bearing portions 36 are screwed into threaded holes 43 of the cylindrical body 24, thus locking the coupling element 31, and consequently the bearing element 34 with the constraining screws 27, to the stator 20.

The retaining element 25 is mounted on the bearing element 34, and the spring 35 is positioned between the retaining element 25 and the bearing element 34. More specifically, a first end of the spring 35 engages the lower abutment surface 47 of the bearing element 34, while a second end of the spring 35 is coupled to the first internal narrowing 49 of the retaining element 25. The force of the spring 35 urges the retaining element 25 far from the cylindrical body 24 and, as a consequence, the second narrowing 52 engages the coupling plates 32. The position of the retaining element 25 is limited and defined by the abutment between the screws 26 and the upper abutment surface 48 of the bearing element 34. In practice, the stator 20 is, manually or automatically, coupled by pressure to the plug gauge 1. More specifically, the retaining element 25 is lifted, in other words it is moved near the handgrip 22 by opposing the force of the spring 35, and the teeth 33 of the coupling plates 32 contact the matching ring 6 of the gauge 1. By applying a thrust on the stator 20 along a longitudinal direction towards the gauge 1, the coupling plates 32 are first forced to open, i.e. to rotate outwards about the respective fulcra 39, and then to close and jam on the matching ring 6. At this moment in time, the retaining element 25 can freely move under the thrust exerted by the spring 35 and can take a working position wherein the second internal narrowing 52 couples to the coupling element 31 in order to keep the teeth 33 of the coupling plates 32 urged against the matching ring 6. The chamfered shape of the teeth 33 and of the matching ring 6 helps the coupling plates 32 to rotate about the respective fulcra 39. Under a working condition, the primary windings of the stator 20 and the secondary windings of the gauge 1 face each other and are only separated by a protection stator- side disk 53 and a protection gauge-side disk 54, respectively, that are both made of non-ferromagnetic materials, preferably plastics, for avoiding to generate parasitic currents.

The stator 20 and the gauge 1 can be disconnected as easily as they are connected, by lifting the retaining element 25 towards the handgrip 22 and applying a force that separates the gauge 1 from the stator 20. Thanks to the mobility of the coupling plates 32 provided by the fulcra 39, such force causes the teeth 33 to release the engagement with the matching ring 6. The illustrated and herein so far described checking system including the quick coupling/uncoupling mechanism 40 ensures a stable mechanical connection between the stator 20 and the gauge 1 and consequently a correct and reliable process of inductive charge. The quick coupling/uncoupling mechanism 40 features a total rotational symmetry about the longitudinal axis of the gauge 1 in terms of mechanical stability of the connection, ease of coupling/uncoupling, and efficiency of contactless power transmission, and thus does not need reference angular positions about the longitudinal axis of the gauge 1 between the gauge 1 and the stator 20. Therefore, the gauge 1 can be connected to the stator 20 at any angular position about its longitudinal axis. The coupling mechanism of the checking system hereinbefore described can be modified without departing from the scope of the present invention.

In an alternative embodiment the quick coupling/uncoupling mechanism can include a simplified mechanical safety device with respect to the device shown in the figures comprising, for example, only the spring 35 which acts as protection and locking for the coupling element 31, or a different element analogously acting, such as a sheath or a hollow cylinder. In a different embodiment, the mechanical retaining element can be dispensed with, and the fulcra 39 and the coupling plates 32 have suitable dimensions in order to ensure a sufficiently stable coupling between the stator 20 and the gauge 1.

Even thought the teeth 33 and the matching ring 6 illustrated in figures 4 and 5 feature particular profiles - concave and convex, respectively, with chamfered edges - it is possible to utilize teeth and matching rings with different profiles, for example convex and concave, respectively, and/or with rounded edges.

Moreover, the positions of the first part 30 and of the second part 50 of the quick coupling/uncoupling mechanism can be inverted in such a way that the first part 30 can be connected to the gauge 1 and the second part 50 to the stator 20.

The shape of the coupling element 31 can differ from the illustrated shape and can include a different number of bearing portions 36 and coupling plates 32, and/or bearing portions 36 and coupling plates 32 differently shaped. Moreover some coupling plates 32 can have a substantially constant thickness, without fulcra explicitly defined by areas with a reduced thickness, and can exploit the intrinsic elasticity of the plate itself. In another alternative embodiment, the coupling element 31 is hollow cylindrically shaped with a substantially cylindrical internal surface whereon there is achieved an annular seat, and includes an elastic element, for example a circular spiral spring located in the annular seat. The elastic element replaces the coupling plates 32 and the relevant teeth 33, that are omitted in the alternative embodiment herein described. The dimensions of the annular seat enable the elastic element to undergo deformations. In order to connect the first part 30 of the quick coupling/uncoupling mechanism 40 to the second part 50, the matching element 6 is inserted by pressure inside the coupling element 31 at the cylindrical internal surface until it contacts the elastic element. Further to contact and to an additional longitudinal thrust, the elastic element first enlarges at a portion of the matching element 6 with a larger diameter, then narrows at a portion of the matching element 6 with a smaller diameter, thus locking the matching element 6 with respect to the coupling element 31.

The quick coupling/uncoupling mechanism can further include coupling elements and/or matching elements with a different shape and/or of different materials, that are intended, for example, to be mutually coupled/uncoupled by virtue of displacements and thrusts occurring along directions substantially transversal to the longitudinal axis of the gauge . In other alternative embodiments, the coupling element can be the female element, and the matching element can be the male element of a threaded coupling or of a bayonet coupling . Moreover, the matching element 6 can be realized integral with the handle 2.

The gauge can include measuring and/or checking units that are different from the probe 7 shown in figure 2, for checking, for example, form deviation of mechanical pieces or external diameters (snap gauges) , or internal diameters on a single section (single plug gauges), with one or more measuring armsets, with one or more movable feelers and one or more measuring devices of LVDT, HBT, strain-gauge type or other types.

Claims

1. System for dimensional and/or form deviation checking of mechanical pieces with: a gauge (1) including: at least one measuring armset with at least one feeler adapted to contact the mechanical piece to be checked, at least one transducer adapted to provide electrical signals representative of displacements of said at least one feeler, a wireless transmission system for transmitting said electrical signals, and at least one accumulator adapted to feed said at least one transducer and said wireless transmission system; and

- a contactless charge device adapted to charge said at least one accumulator and including a stator with primary windings, and secondary windings connected to the gauge and electrically coupled to said at least one accumulator, said primary and secondary windings realizing an inductive coupling, characterized in that said contactless charge device includes a quick coupling/uncoupling mechanism (40) between said stator (20) and said gauge (1) .

2. The system according to claim 1, wherein said quick coupling/uncoupling mechanism (40) includes a coupling element (31) and a matching element (6) that are connected to one and the other of said gauge (1) and stator (20), and adapted to mutually cooperate.

3. The system according to claim 2, wherein said coupling element (31) includes coupling plates (32) with teeth

(33) adapted to cooperate with the matching element (6) .

4. The system according to claim 3, wherein said coupling plates (32) are elastically deformable.

5. The system according to claim 3, wherein said coupling plates (32) include fulcra (39) .

6. The system according to claim 5, wherein said coupling plates (32) include preferential elastic deformation areas that define said fulcra (39) .

7. The system according to any one of claims 5 and 6, wherein said coupling element (31) includes an external rim (37) , each of said coupling plates (32) being adapted to rotate about a direction tangent to said external rim (37) and defined by the associated fulcrum

(39) .

8. System according to any one of claims 2 to 7, wherein said matching element (6) includes a matching surface (13) featuring symmetry of rotation.

9. The system according to claim 8, wherein said matching element (6) is substantially annular shaped.

10. The system according to any one of claims 3 to 9, wherein said quick coupling/uncoupling mechanism (40) includes a mechanical safety device.

11. The system according to claim 10, wherein said mechanical safety device includes a protection and locking element (25) with internal surfaces (52) adapted to engage the teeth (33) .

12. The system according to claim 11, wherein said mechanical safety device includes a spring (35) adapted to cooperate with the protection and locking element (25) for urging said internal surfaces (52) against the teeth (33) of the coupling plates (32) .

13. The system according to any one of claims 11 and 12, wherein said quick coupling/uncoupling mechanism (40) includes constraining elements (27) adapted to engage constraining surfaces (29) of the protection and locking element (25) for defining and keeping an angular arrangement of the protection and locking element (25) .

14. The system according to any one of claims 1 or 2, wherein said quick coupling/uncoupling mechanism (40) includes a threaded coupling between the gauge (1) and the stator (20) .

15. The system according to any one of claims 1 or 2, wherein said quick coupling/uncoupling mechanism (40) includes a bayonet coupling between the gauge (1) and the stator (20) .

16. The system according to any one of claims 2 to 15, wherein said coupling element (31) is connected to the stator (20) and said matching element (6) is connected to the gauge (1) .