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An apparatus for testing the seal of tyre rims
Patents
Figure 1: The apparatus in the working position, tyre rim, drawn with dots and dashes.
An apparatus for testing the seal of tyre rims Patent number: GB 2274 517A Publication date: 27 July 1994 Inventor: Faust0 Sala Applicant: Premaq Impex Inc. The use of tubeless tyres is widespread in the car sector. The adoption of this kind of tyre requires the rims onto which the tvres are mounted to have a perfect pneumatic seal, and therefore requires careful verification of the rims to discover any possible faults in construction which could
Sealing Technology No. 24
testing the seal of a
compromise the pressure in the tyres themselves. In particular, rims cast in light alloys (aluminium and/or magnesium alloys) are subject to microporosity or microfissure because of their conformation. However, in such a system, checks are somewhat subjective. In addition, such a technique requires long checking times and therefore contributes to high production costs. The aim of this invention is to realize an apparatus capable of testing vehicle tyre rims, to check whether they are permeable to air or not. The new apparatus comprises a base structure, whose upper surface houses equipment for
supporting the rim to be tested and, at the ends of the four sides, anchorages for the support columns of an upper structure. Inside the base structure, in its central part, a device bears a head with electrical checking sensors, which can be moved between a retracted rest position and an extended working position. This device is moved by a pneumatic or hydraulic cylinder, or alternatively by means of a ballscrew with related electrical driving and control motor. The upper structure by the columns is composed of a fured part and a mobile part comprising a sealing bell chamber and a device for locking the tyre rim. The tyre rim is positioned on a gasket on the lower equipment or structure, and the mobile part above is lowered onto it. The bell chamber insulates the tyre rim hermetically in such a way that air can be sent into the air space created between the outer face of the tyre rim and the inner face of the bell chamber. Sealing is carried out axially to the tyre rim by the locking device, which by compressing the tyre rim onto the outer edges obtains the airtight chamber which allows air or testing gas to be sent in. The above sealed condition is achieved by appropriate gaskets, suitable for tyre rims of all sizes, which press against the outer edges of the tyre rims themselves; one gasket is fixed onto the upper surface of the base structure and the other onto the lower part of the locking device: both can be replaced easily and quickly. The locking device or frame bears a sensor holder head. The sensor holder head preferably comprises a base and a cap: the cap bears a number of sensors suitable for detecting an air or gas leak. In one preferred embodiment these are ultrasound sensors. The data detected by the sensor unit can be displayed on an electric panel of the machine. The discrimination between good wheels and wheels to be rejected is automatic. The new apparatus allows the user to check the sealing of tyre rims easily, quickly and safely: therefore it helps to keep down production costs of the tyre rims themselves. It can also be used for annular bodies other than tyre rims.
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Figure 1: The apparatus in the working position, tyre rim, drawn with dots and dashes.
An apparatus for testing the seal of tyre rims Patent number: GB 2274 517A Publication date: 27 July 1994 Inventor: Faust0 Sala Applicant: Premaq Impex Inc. The use of tubeless tyres is widespread in the car sector. The adoption of this kind of tyre requires the rims onto which the tvres are mounted to have a perfect pneumatic seal, and therefore requires careful verification of the rims to discover any possible faults in construction which could
Sealing Technology No. 24
testing the seal of a
compromise the pressure in the tyres themselves. In particular, rims cast in light alloys (aluminium and/or magnesium alloys) are subject to microporosity or microfissure because of their conformation. However, in such a system, checks are somewhat subjective. In addition, such a technique requires long checking times and therefore contributes to high production costs. The aim of this invention is to realize an apparatus capable of testing vehicle tyre rims, to check whether they are permeable to air or not. The new apparatus comprises a base structure, whose upper surface houses equipment for
supporting the rim to be tested and, at the ends of the four sides, anchorages for the support columns of an upper structure. Inside the base structure, in its central part, a device bears a head with electrical checking sensors, which can be moved between a retracted rest position and an extended working position. This device is moved by a pneumatic or hydraulic cylinder, or alternatively by means of a ballscrew with related electrical driving and control motor. The upper structure by the columns is composed of a fured part and a mobile part comprising a sealing bell chamber and a device for locking the tyre rim. The tyre rim is positioned on a gasket on the lower equipment or structure, and the mobile part above is lowered onto it. The bell chamber insulates the tyre rim hermetically in such a way that air can be sent into the air space created between the outer face of the tyre rim and the inner face of the bell chamber. Sealing is carried out axially to the tyre rim by the locking device, which by compressing the tyre rim onto the outer edges obtains the airtight chamber which allows air or testing gas to be sent in. The above sealed condition is achieved by appropriate gaskets, suitable for tyre rims of all sizes, which press against the outer edges of the tyre rims themselves; one gasket is fixed onto the upper surface of the base structure and the other onto the lower part of the locking device: both can be replaced easily and quickly. The locking device or frame bears a sensor holder head. The sensor holder head preferably comprises a base and a cap: the cap bears a number of sensors suitable for detecting an air or gas leak. In one preferred embodiment these are ultrasound sensors. The data detected by the sensor unit can be displayed on an electric panel of the machine. The discrimination between good wheels and wheels to be rejected is automatic. The new apparatus allows the user to check the sealing of tyre rims easily, quickly and safely: therefore it helps to keep down production costs of the tyre rims themselves. It can also be used for annular bodies other than tyre rims.
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