Patent GB-1002161-A (GB)
Title: A method of non-destructively measuring the thickness of layers of fat, of animal carcasses, and measuring apparatus for carrying the method into effect
IPC: G01B17/02
Filed: 1962-03-13
Abstract: 1,002,161. Measuring length acoustically. DANSK SVEJSECENTRAL. March 13, 1962 [March 13, 1961], No. 9641/62. Heading H4D. In an arrangement for measuring the thickness of the layers of fat of an animal carcass, the thickness of the non-fat portion is measured by known acoustic energy methods utilizing pulse-echo or resonance techniques and this measurement is subtracted from a measurement of the total thickness, made by conventional mechanical means involving measuring scales &c., to derive a measurement of the thickness of the fat layers. Advantages of this arrangement over known methods of direct measurement of fat layer thickness involving acoustic energy techniques are the absence of; errors due to spurious reflections from connective tissue embedded in the fat layer; errors resulting from a reduction in the fat layer thickness due to compression of the latter by the acoustic transducer, to effect adequate coupling and; errors due to variations in the animal skin condition as a result of singeing associated with the slaughtering. Fig. 1, shows one arrangement for carrying out the invention and comprises a mechanical measuring device consisting of two adjustable arms 1, 2, the distance between the respective contact surfaces 4, 5 of which may be read on a calibrated scale 15. The surface 5 comprises an electro-acoustic transducer 13 (piezo-electric crystal or magneto-strictive vibrator) coupled to known means (not shown) which, utilizing the pulse-echo or the resonance technique, produces a measure of the distance between the face of transducer 13, which is in contact with the inner (meat) surface of a split animal carcass, and the boundary 12 between the meat 8 and the fat layer 9. The difference between the two measurements a and b, thus obtained is equal to the thickness of the fat layer 9. In a modification of the arrangement of Fig. 1, the index 16 carried by arm 2 is replaced by a calibrated scale the zero of which is utilized as an index (Fig. 2, not shown) and to facilitate scale reading when the device is employed for measurement of the other half of the carcass the two scales are calibrated on both sides (Fig. 3, not shown). Inboth the latter embodiments the thickness a of the meat layer 8 (Fig. 1), as determined by the electro-acoustic measurement, determines the point on scale 15 against which the fat thickness is read on the other scale. In Figs. 4 to 6 inclusive which show a further embodiment, also intended for measurement on both sides of the carcass (assumed split down the centre but joined at the head), the arm 2 of the mechanical measuring device carries two scales 24, 25 adjacent to which are respective scales 26, 27 formed on a flexible tape 19 one end 21 of which is secured to a member in rigid association with the arm 2 via a tensioning mechanism 22, 23, the tape then passing over rollers 28, also in rigid association with arm 2 and via a roller 29, in rigid association with arm 1, to an attachment point carried by arm 2. In operation a worm-wheel 31 rotatably supported by a friction clutch 32 (carried by arm 2) and co-acting with a screw-thread 30 (carried by arm 1) allows the separation between the arms 1, 2 to be roughly adjusted. Fine adjustment is then effected by rotation of the knob 34 and the resulting movement of roller 29 moves the scales 26, 27, carried by the tape 19, relatively to the scales 24, 25. In this case, however, the movement of the tape relative to the latter scales is twice as great as the relative movement of the arms 1, 2 and to compensate for this the spacing of the graduation divisions on all scales is doubled.