METHOD AND DEVICE FOR DETERMINING THE WEIGHT OF PIGS

Abstract: To determine the weight of a pig, a measure of length and a measure of width of the pig are established, at least substantially without touching the pig. Then, the weight is determined as a function of the established measures of length and width. A device for determining the weight of a pig has a frame (1a, 1b), and at least two mutually displaceable alignment means (2) which are mounted on the frame and adapted to establish a measure of length and a measure of width of the pig in order to determine the weight of the pig as a function of these measures.

Description: METHOD AND DEVICE FOR DETERMINING THE WEIGHT OF PIGS The present invention relates to a method and a device for determining the weight of pigs. The invention may be used for picking out pigs for slaughter. It is important for the breeder to know exactly when to slaughter a pig, since maximum price per kilo is paid when the weight of the slaughtered pig lies within a given range. Thus, it is desirable that the pigs to be slaughtered are picked out according to weight. As a rule, the weight is established either some time before or when the pigs are to be taken away to be slaugh¬ tered. Previously, the pigs were subjected to visual in¬ spection, giving a rough estimate of the weight. Naturally enough, visual inspection is not very accurate, and above all requires great experience of the person making the inspection. Also, the pigs can be weighed on a mechanical pair of scales, which gives highly accurate values, but involves problems in the handling of the pigs. The weighing opera¬ tion puts the animals under stress, which results in lower-quality meat. The object of the present invention is to provide a method and a device for determining the weight of pigs without-employing an -experienced inspector and without putting the pigs under stress. According to the invention, this object is achieved by a method which is characterised by establishing a mea¬ sure of length and a measure of width of the pig, at least substantially without touching the pig, and determining the weight as a function of the established measures of length and width. To this end, use is made of a device according to the invention, which is characterised by a frame, and at least two mutually displaceable alignment means which are mounted on the frame and adapted to estab¬ lish a measure of length and a measure of width of the pig in order to determine the weight of the pig as a function of said measures. A calculator or microprocessor can be provided on the frame to facilitate the conversion from units of length to unit of weight. The weight-determining device may further be equipped with a means for reading an identification strip, or the like, which is attached to the pig and on which is record¬ ed individually identifying information, which e.g. can be read by magnetic or optical means. In addition, the weight-determining device can be equipped with a means, e.g. a paint spraying means, for marking pigs of the right weight, so that these are easily picked out later. The invention will be described in more detail below with reference to the accompanying drawings, in which Fig. 1 is a perspective view of an embodiment of the invention; Fig. 2 is a top plan view of the device shown in Fig. 1; and Fig. 3 is a perspective view of a second embodiment of the invention. The embodiment illustrated in Figs 1 and 2 has a frame comprising two arms la, lb which are crossed and which each carry two light sources 2. The rays or beams 3 from the light sources 2 are closely gathered or colli- mated and directed downwards, substantially parallel to one another. At least one of the light sources 2 on each arm la, lb is displaceable in the longitudinal direction of the arm. The two crossed arms la, lb of the frame are not fixedly interconnected at the centre of the cross, and the short arm lb can be moved in the longitudinal direction of the long arm la. Preferably, one of the two light sources 2 on each arm la, lb is displaceable in the longitudinal direction of the arm, whereas the other of the two light sources 2 on each arm la, lb is fixedly mounted, conveniently at one end of the arm. Length scales are provided on top of the two arms la, lb and, preferably, graduated from the light source 2 fixedly mounted on each arm. In addition, the device supports a calculator or microprocessor 4 for processing the measured values. Alternatively, the length scales can be equipped with transducers for recording the measured values. The device according to the invention operates as follows. The frame la, lb is positioned straight above the pig, suitably when this is feeding. The fixed light sources 2 are adjusted such that the light rays 3 shine on the tailhead of the pig as well as on one of its sides, preferably just behind the forelegs. The frame la, lb is maintained in this position, and the two remaining light sources 2 are so adjusted that the light rays 3 therefrom shine e.g. on a specific vertebra of the neck and on the other side of the pig, respectively. Then, a measure of length and a measure of width of the pig can be read on the two scales. The measured values may subsequently be fed to the microprocessor 4, which e.g. can convert the values, with the aid of a constant, to weight in kilos. Alternatively, the values supplied to the microprocessor 4 can give a range of weight encompassing the weight of the pig. These items of information will tell whether this is the right time to slaughter the pig. It will be appreciated that the measuring device can be designed in many different ways. For instance, the num¬ ber and type of light sources 2 may vary. Optionally, the light sources 2 can be replaced with other alignment means, such as plummets freely suspended from the frame la, lb. These plummets can be adjusted along the arms la, lb in similar manner as the light sources 2 to perform the measuring operation. There are also several ways of adjusting the light sources or the alignment means, as well as various ways of performing the reading operation, e.g. involving other easily identified points on the pig. Fig. 3 illustrates a second embodiment of the device according to the invention. This embodiment has a single elongate member in the form of a tube 5. One end portion 6 of the tube 5 forms a handle of the device. Further, two holding blocks 7, 8 for a guide bar 9 parallel to the tube 5, as well as a first light source 10 are fixedly mounted on the tube 5. A battery unit 11 is releasably mounted between the holder 7 and the light source 10. Two second light sources 12, 13 are formed with holes for the tube 5 and the guide bar 9 and are interconnected by means of a connecting bar 14, so as to be jointly displaceable along the tube 5 between the holding blocks 7, 8. The light sources 10, 12 and 13 are connected to the battery unit 11 by means of a switch 15 mounted on the light source 10, and then emit collimated, substantially parallel beams of light which in Fig. 3 are directed downwards. The upper side of the battery unit 11 is equipped with two scales 16, 17, and an indicator 18 is mounted on the second light source 12 and extends in over the scales 16, 17 to indicate thereon the position of the light source 12 and the light source 13, respectively, relative to the light source 10. Advantageously, the scales 16, 17 are so graduated that the sum of the indicated values gives a range of weight for the pig whose length and width measures have been determined by the device. For purposes of calibration, the position of the indicator 18 relative to the second light source 12 can be adjustable. The optimum range of weight, i.e. the range where the price per kilo is at a maximum, has lower and upper limit values which both increase as the proportion of meat in per cent of the slaughtered pig increases. Since the pro- portion in per cent of meat correlates with the quotient resulting from the division of the length and the width of the pig, the device according to the invention is able to take also this fact into account, e.g. by establishing the length and width measures as deviations from a given mini¬ mum length and a given minimum width and by determining the range of weight as the sum of these deviations, more importance being attached to the deviation of width than to the deviation of length. For instance, the scales 16, 17 can be graduated 1-5 in the direction away from the light source 12 towards the holder 7, and the distance between the marks on the length scale, e.g. the scale 16, can be substantially longer than the corresponding dis¬ tance on the width scale 17. Thus, the scales 16, 17 can be so positioned in relation to the indicator 18 that the optimum range of weight has been established if the sum of the read values is e.g. 6. In the case of a comparatively short and broad pig, i.e. a pig with a comparatively low proportion of meat in per cent, the value 6 then corre¬ sponds to a lower weight than if the pig is comparatively long and thin, i.e. has a comparatively high proportion of meat in per cent. Thus, adjustment to the above-mentioned optimum range of weight can be performed. To enable feedback of information from the slaughter¬ house to the breeder, an identification strip of badge can be conveniently attached to each pig. This strip or badge may contain optically or magnetically readable information identifying the individual pig. If so, the device accord¬ ing to the invention may include a detector 19 mounted on the holding block 8, and a change-over switch 20 arranged at the handle 6 to activate the detector 19. At the handle end, a character display 21 can be provided for displaying the information read by the detector 19. Further, the device may include a printer for recording this informa¬ tion. At the slaughter-house, the strip or badge can be read in a corresponding manner and the information obtain¬ ed be added to information on the weight of the slaughter- ed pig and the quality of its meat, e.g. the proportion in per cent of meat, and these items of information can then be forwarded to the breeder and be used both in the conti- nuous operation of the device according to the invention, as well as in breeding. To make it easier to pick out the pigs which in the determination of weight were found to be ready for slaugh- ter, the device according to the invention may finally include a marking means 22 fixed to the holding block 8. The means 22 can be activated by a change-over switch 23 provided at the handle 6 and may, for instance, be a paint spraying means, thereby making it easy to pick out the painted pigs destined for the slaughter-house.

Claims: CLAIMS 1. Method for determining the weight of a pig, c h a r a c t e r i s e d by establishing a measure of length and a measure of width of the pig, at least sub¬ stantially without touching the pig, and determining the weight as a function of the established measures of length and width. 2. The method of claim 1, c h a r a c t e r i s ¬ e d by determining the weight on the basis of the product of the measures of length and width, preferably as said product multiplied by a given constant. 3. The method of claim 1, c h a r a c t e r i s - e d by determining the weight as the sum of the devia¬ tions of the measures of length and width from given mini¬ mum length and width measures, more importance being pre¬ ferably attached to the deviation of the measure of width than to the deviation of the measure of length. 4. The method of any one of claims 1-3, c h a r ¬ a c t e r i s e d by establishing the measure of length as the distance between easily identified points on the neck of the pig and at the tailhead, and by establishing the measure of width as the largest width of the pig at its forelegs. 5. Device for determining the weight of a pig, c h a r a c t e r i s e d by a frame (la, lb; 5), and at least two mutually displaceable alignment means (2; 10, 12, 13) which are mounted on the frame and adapted to establish a measure of length and a measure of width of the pig in order to determine the weight of the pig as a function of said measures. 6. The device of claim 5, c h a r a c t e r i s ¬ e d in that the alignment means (2) consist of light sources emitting collimated, substantially parallel beams of light. 7. The device of claim 5 or 6, c h a r a c t e r ¬ i s e d in that the frame (5) has an elongate member on which a first alignment means (Id) is fixedly mounted and two second, spaced-apart alignment means (12, 13) are arranged so as to be jointly displaceable along said member. 8. The device of claim 5 or 6, c h a r a c t e r ¬ i s e d in that the frame (la, lb) comprises two crossed arms, each equipped with two alignment means (2). 9. The device of claim 7 or 8, c h a r a c t e r ¬ i s e d by two scales (16, 17), and at least one indi¬ cator (18) which is movable relative to the scales and adapted to indicate the measure of length and the measure of width, respectively, relative to a given minimum mea- sure of length and width, respectively, said scales being so graduated that the sum of the indicated measures gives a certain range of weight. 10. The device of any one of claims 5-9, c h a r ¬ a c t e r i s e d by a means (19) which is mounted on the frame (5) and adapted to read an identification strip or the like attached to the pig.

Inventors: FRIBERG PER-OLOF, FRIBERG, PER-OLOF
Applicants: FRIBERG PER OLOF, FRIBERG, PER-OLOF
Application year: 1992
Main classification: G01G17
IPC codes: G01B11, G01G17