BORE GAUGING APPARATUS

Abstract: A gauging head, for use in measuring internal dimensions of a bottle neck bore, comprises a probe (10) which is arranged to be introduced a predetermined distance into the bore. The probe bears eight radially movable gauging elements (16, 20) positioned at the opposite ends of four diameters in a common plane. Each element comprises a blade (16) which is accommodated for radial movement in a slot (18) of the probe. A cam face (26) presented on an arm (22) extending from the blade is engaged by a transducer probe (28) for sensing radial movements of the gauging element. In use of the head, signals from the transducer probes are recorded at each of a plurality of different axial positions during withdrawal of the probe from the bore.

Description: BORE GAUGING APPARATUS This invention is concerned with improvements in or relating to bore gauges such as may be used on line in the glass bottle manufacturing and filling industries. Glass bottles are commonly checked, on line, by a simple go/no-go gauging arrangement involving a plunger which either enters the bottle neck or does not. Such gauging simply serves to identify bottles having undersize neck bores, and does not provide any accurate information regarding the quality of the production. The invention provides, in one of its aspects, a bore gauging head comprising a probe arranged to enter a bore and bearing a plurality of radially moveable wall-contacting gauging elements which are distributed about the longitudinal axis of the probe and are urged radially outwards to engage the bore wall, and sensing means associated with each gauging element and operative to give a signal indicative of the radial position of the element. The signals from the sensing means may be processed by means of a computer to provide information on bore profiles. In a preferred construction of probe, there are eight contacts arranged at the opposite ends of diameters as four pairs in a common transverse plane (perpendicular to the probe axis) . However, other numbers and arrangements of contacts could be employed. Each gauging element may present a cam face which is arranged to vary displacement of a sensing element of the sensing means as the radial position of the gauging element changes. The sensing means may comprise a transducer probe which abuts the cam face. Conveniently, the cam face can be presented on an arm of the gauging element which extends radially outwards from a contact blade which is accommodated for radial movement in a slot in the probe. The invention provides, in another of its aspects, a method of measuring dimensions of a bore using a gauging head in accordance with the last preceding paragraph but three comprising inserting the probe a predetermined distance into the bore, withdrawing the probe from the bore, and recording the signals given by the sensing means at each of a plurality of different axial positions during withdrawal of the probe. In yet another of its aspects, the invention provides bore gauging apparatus for use in a method according to the last preceding paragraph, the apparatus comprising a bore gauging head in accordance with the last preceding paragraph but four, means operable to insert the head probe a predetermined distance into a bore and subsequently to withdraw the probe from the bore, and means arranged to record the signals given by the sensing means at predetermined positions during withdrawal of the probe from the bore. There now follows a detailed description, to be read with reference to the accompanying drawing, of bore gauging apparatus and its use, which illustrate the invention by way of example. The accompanying drawing is a part-sectioned view of a gauging head of bore gauging apparatus. Gauging apparatus suitable for use in measuring dimensions of glass bottle neck bores at high speed comprises a gauging head and means (not shown) arranged to cause vertical reciprocation into and out of the bores. The bottle necks are entered by a probe 10 which comprises a tapered leading portion 12 which serves to eliminate any grossly undersize bottle necks from the measuring process. Occasionally glass bottle necks may be formed which are substantially wholly blocked, and others may have substantial internal deformities. In either case the leading portion 12 of the probe will fail to pass through the neck. Above the leading portion 12, the probe comprises a cylindrical pilot bar 14 of similar diameter to the leading portion 12. The bar forms guideways for eight elongate contact blades 16 which lie in eight longitudinally-extending slots 18 formed in the bar. The blades can move radially in the slots and are spring-loaded radially outwards. Bottom end portions of the blades bear spherical contact beads 20 (one on each blade) for point contact with a bottle bore wall. (In the drawing, the contact blade shown is illustrated fully depressed into its slot 18, whereas for gauging purposes at least the bead 20 would project from the slot.) The eight contact blades 16 are uniformly distributed about the pilot bar 14, the contact beads 20 being arranged in four pairs at opposite ends of four diameters in a common transverse plane of the bar. Each of the eight contact blades 16 is connected at its upper end to a radially-outwardly extending cam-driving arm 22 which carries a cam block 24 on an upper surface at its outer end; the blade 16 (and bead 20) , the arm 22 and the block 24 together make up a radially movable gauging element. The cam block has an inclined upper sensing surface 26 which extends linearly downwards in a direction radially inward of the gauging head. A vertically mounted transducer probe 28, secured in a transducer block 30 of the gauging head, bears against the sensing surface 26 so as to respond electrically to the radial position of the cam block, and accordingly to the radial position of the gauging element. In use, the eight transducers 28 of the gauging head send signals to a monitoring and recording system of the gauging apparatus which interprets the signals received to assess the relative positions of the contact beads 20 of the gauging elements and so provide a measure of the profile of a bottle neck bore. The apparatus comprises means (not shown) for driving the gauging head downwards into a bottle and means (also not shown) for monitoring the vertical position of the head; suitable means for the latter purpose can comprise a second transducer and cam arrangement, a vertically inclined face of a cam member, secured to the head, sliding against a horizontally disposed transducer as the head moves up and down. In use of the apparatus, the probe 10 is inserted downwards into the bottle until the top of the bottle neck abuts a ceiling surface 32 of a downwardly facing annular cavity 34 extending about an upper portion of the pilot bar 14. From the height datum so established, the head is then raised and readings from the eight gauging transducers 28 noted at a plurality of (e.g. four) height positions within the bottle neck as the probe is withdrawn from the bottle. The means for reciprocating the gauging head vertically comprises a drive bar 36 from which the head is suspended by means of a universal joint arrangement 38. The universal joint accommodates slightly varying alignment of bottles being presented on a conveyor. The gauging head is designed to enable different diameters of pilot bar 14 to be exchanged readily for the purposes of gauging different sizes of bottle neck. The pilot bar is carried by a locating ring 40 which forms the cavity 34 hereinbefore referred to and is secured to the underside of an annular housing base plate 42, The ring is located centrally in the base plate by means of a positioning collar 44 which is secured to the upper side of the locating ring and fits into a central aperture of the base plate. The assembly of the pilot bar 14, the locating ring 40 and the positioning collar 44 can be exchanged for another providing a different diameter of pilot bar. Provision will now be described for accommodating the contact blades 16 at the different diameters. Each of the transducer probes 28 is mounted in a separate transducer block 30 which is guided for adjustment of its radial position between a housing cover plate 46 and the housing base plate 42; the cam blocks 24, the cam- driving arms 22 (and so the blades 16) and linear bearings 48 which enable the arms to move freely radially relative to the transducer blocks, remain assembled with the transducer blocks and follow such adjusting movements. In order to locate those transducer block assemblies in an appropriate radial position for any particular pilot bar size, an internally threaded bush 50 projects downwards from each transducer block to engage in an axially-centred annular slot 52 formed in the upper surface of the pilot locating ring 40, the bush passing through a slot 54 in the housing base plate 42. The locating ring 40 is secured to the underside of the housing base plate by means of screws 56 engaged through the locating ring and into the eight bushes 50.

Claims: CLAIMS 1 . A bore gauging head comprising a probe (10) arranged to enter a bore and bearing a plurality of radially moveable wall-contacting gauging elements (16, 20) which are distributed about the longitudinal axis of the probe and are urged radially outwards to engage the bore wall, and sensing means associated with each gauging element and operative to give a signal indicative of the radial position of the element. 2. A gauging head according to Claim 1 in which there are provided a plurality of pairs of gauging elements (16, 20) arranged to engage the bore wall at points lying in a transverse plane of the probe, the contact points for each pair being at opposite ends of a diameter of the probe. 3. A gauging head according to Claim 2 in which there are four pairs of gauging elements (16, 20) which engage the wall at eight points which are uniformly disposed about the axis of the probe. 4. A gauging head according to any one of claims 1 to 3 in which each gauging element (16,20) presents a cam face (26) which is arranged to vary displacement of a sensing element of the sensing means as the radial position of the gauging element changes. 5. A gauging head according to Claim 4 in which the sensing means comprises a transducer probe (28) which abuts the cam face (26) . 6. A gauging head according to either of claims 5 and 6 in which the cam face (26) is presented on an arm (22) of the gauging element which extends radially outwards from a contact blade (16) which is accommodated for radial movement in a slot (18) in the probe. 7. A method of measuring dimensions of a bore using a gauging head in accordance with any one of Claims 1 to 6 comprising inserting the probe a predetermined distance into the bore, withdrawing the probe from the bore, and recording the signals given by the sensing means at each of a plurality of different axial positions during withdrawal of the probe. 8. Bore gauging apparatus for use in a method according to claim 7 the apparatus comprising a bore gauging head in accordance with any one of claims 1 to 6, means operable to insert the head probe a predetermined distance into a bore and subsequently to withdraw the probe from the bore, and means arranged to record the signals given by the sensing means at predetermined positions during withdrawal of the probe from the bore. 9. A bore gauging head substantially as hereinbefore described with reference to the accompanying drawing. 10. A method of measuring dimensions of a bore substantially as hereinbefore described with reference to the accompanying drawing. 11. Bore gauging apparatus substantially as hereinbefore described with reference to the accompanying drawing.

Inventors: BURTON BARRIE CHARLES, MOWATT JAMES STANLEY, BURTON, BARRIE, CHARLES, MOWATT, JAMES, STANLEY
Applicants: BURTON BARRIE CHARLES, MOWATT JAMES STANLEY, SYSTEM CONTROL LTD, BURTON, BARRIE, CHARLES, MOWATT, JAMES, STANLEY, SYSTEM E CONTROLS LIMITED
Application year: 1996
Main classification: G01B5
IPC codes: G01B5, G01B7, G01B21