Patent GB-1495313-A (GB)
Title: Apparatus for inspecting the spacing of steel ply cords in pneumatic tyres
IPC: B07C5/34
Filed: 1975-04-28
Abstract: 1495313 Tyre inspection apparatus BRIDGESTONE TIRE KK 28 April 1975 [9 May 1974] 17556/75 Heading B7C Apparatus for inspecting the spacing of radial steel cords in pneumatic tyres comprises a mechanism 1 for feeding tyres one by one to an inspection station 4 of the apparatus, a rim which serves to mount a tyre in an inspection position at the station 4 and is split into upper and lower annular halves 29, 30, a drive mechanism connected to the rim for rotating it, electromagnetic detectors 105, 105<SP>1</SP> mounted movably on a movable carriage 118 at the station 4 for movement towards and away from inspecting points adjacent respective sidewalls of a tyre in the inspection position, an electric circuit connected to the detectors for producing a disqualifying signal if an irregularity in the cord spacing is detected by the detectors, and means for separating qualified and disqualified tyres. In the illustrated embodiment tyres are fed to a conveyer 5 at the inspection station by a roller conveyer 2 provided with stop members 8 carried on arms (9) (Fig. 2, not shown) pivoted to swing across the conveyer 2 under the control of a piston-cylinder device 14 to block or allow passage of a tyre. The lower rim half 30 is carried by a rotatable shaft 44 and is connected by pivoted arms 47 to a pistoncylinder device 51 whereby it can be vertically displaced to carry a tyre thereon into the inspection position in which the tyre also engages the upper rim half 29. Air is supplied through the shaft 44 to inflate for inspection a tyre gripped between the rim halves 29, 30. The upper rim half 29 is carried by a rotatable shaft 31 connected through a reduction gear unit 34 to an electric motor 33. A tyre diameter detecting mechanism 66 is provided at the inspection station comprising an arm (69) (Fig. 4, not shown) pivoted to swing a roller thereon into contact with the tread of a tyre on the lower rim half 30 thereby moving cam members to engage and actuate limit switches in a number corresponding to the distance moved by the arm and hence to the diameter of the tyre. The actuation of the switches generates a signal which sets a limit mechanism (139) (Fig. 5, not shown) to limit the travel of the carriage 118 according to the diameter of the tyre to be inspected so that the detectors 105, 105<SP>1</SP> are brought to the correct inspection points. The carriage 118 is movable horizontally by means of an electric motor 131 and the detectors 105, 105<SP>1</SP> are movable vertically on the carriage by means of piston-cylinder devices 116, 116<SP>1</SP>. Each detector 105, 105<SP>1</SP> comprises an iron core, Fig. 7, having a primary coil 108 wound thereon and a secondary coil 106 with two oppositely wound parts located on respective limbs of the core. The core and coils are housed in a casing of non-magnetic material filled with synthetic resin. The primary coil 108 is connected to an oscillator 156, Fig. 8, and in operation imbalance, e.g. caused by one part of the secondary coil 106 being over a cord and the other part being between abnormally widely spaced cords, causes a voltage to be generated in the coil 106. This voltage is fed through an amplifier to a circuit including voltage comparators 159-162, monostable multivibrators 163, 166 and AND circuits 164, 167 which compares the voltage generated in the coil 106 with reference voltages representing the acceptable cord spacing and produces a signal if an abnormally wide or narrow cord spacing or cord overlap is detected. The signal actuates a piston-cylinder device, e.g. 122, to cause a marker 121 to mark the irregularity. Tyres emerging from the inspection station pass to a conveyer 6 pivotable downwardly so that disqualified tyres can be sent to a different station to qualified tyres.