The present invention relates to a method for deboning pieces of meat, for instance thighs and drumsticks of broilers, and of the type described in the introductory part of claim 1.

By slaughtering of poultry, for instance broilers, the cut up of the broilers is to a greater extent carried out according to the wishes of the customers by means of a cut up line along which the different cut up stations or apparatuses are placed. In this connec¬ tion it is known to execute mechanical deboning of thighs and drumsticks, however pre¬ ferably when the thighs and drumsticks already are separated.

From EP-B 1-362 457 a mainly drum-shaped apparatus is known for deboning thighs and drumsticks of poultry, for instance broilers, while thighs and drumsticks still are interconnected. The apparatus, which is provided with a number of deboning aggrega¬ tes along the circumference of the drum, in practice has not been distributed very much, which may be due to the complicated construction of the apparatus and that it is difficult to clean.

The invention has for its purpose to provide a method for deboning pieces of meat, for instance interconnected thighs and drumsticks of broilers, and which by simple provisions makes it possible to obtain an effective mechanical deboning of pieces of meat of the mentioned type.

The method according to the invention is distinctive in that opposite stripped bone ends of interconnected thighs and drumsticks at the same time are placed between mutually displacably arranged pair of holding jaws in such a manner, that the holding jaws grasp around opposite bone ends, that the holding jaws are displaced towards each other, scrape off the meat and squeeze around the meat scraped off, that displacable tube means being placed outside the holding jaws and on level with the bone ends simul¬ taneously are displaced inwardly towards each other and lead around and fixing the stripped bones, that the holding jaws, when they are squeezed around the meat scraped off, are opened sufficiently that outer end part of the respective tube means from each side may be pressed against the outside of the squeezed meat, that an internal tubular knife from a position in one of the tube means is moved through the meat and cuts free the meat from the knee joint, that the bones cut free, for instance by means of compres-

sed air, are blown out through the tube means opposite said tubular knife, and that holding jaws and tube means again are lead away from each other for disengagement of the deboned meat, for instance by means of suitable scraper means. By means of simple techinical provisions it hereby becomes possible to obtain an effective and optimum me- chanical deboning of pieces of meat of the type mentioned.

In order to make further effect the method according to the invention a particular pivoting feeder arm with an unit holder for placing the outer stripped bone ends of the piece of meat in said holding jaws may advantageously be used, as the deboning aggregates hereby may rotate with a larger speed in relation to the drum-shaped basic part - which however implies, that each of the deboning aggregates comprises said par¬ ticular feeder arm.

To secure correct cutting free of the meat being squeezed around the knee joint, said in- ternal tubular knife advantageously may be rotated at the same time as it is lead trough the meat around the knee joint.

The invention furthermore relates to an apparatus for deboning pieces of meat, mainly interconnected thighs and drumsticks of broilers, comprising a stationary drum-shaped basic part with a number of uniform deboning aggregates, which are distributed along the circumference of the drum, and said deboning aggregates being rotated around the drum, the surface of which is provided with steering recesses for activation of the deboning aggregates, each being mounted on mutually parallel gliding rods secured be¬ tween rotating gables, which apparatus is distinctive in that each of said deboning ag- gregates comprises mutually displacably arranged pair of pivoting holding jaws being a- dapted to grasp around opposite bone ends of said pieces of meat, and to be displaced towards each other for scraping off the meat from the bones in such a manner, that the holding jaws are squeezed around the meat scraped off, displacable tube means being placed outside the holding jaws and being adapted to be simultaneously displaced inwardly towards each other and to be lead around the stripped bones for fixing these, an internal tubular knife being adapted to - from a position in one of said tube means - be moved through the squeezed meat for cutting this free from the knee joint, and di¬ scharge means being adapted to discharge the scraped bones preferably through the tube means opposite said tubular knife.

To increase the capacity the capacity of the deboning apparatus according to the invention by rotating the deboning aggregates with a larger speed in relation to the

drum-shaped basic part each of the deboning aggregates furthermore is provided with a particular pivoting feeder arm, which at the outmost end is provided with an unit holder, and being adapted for placing the outer stripped bone ends of the piece of meat in said holding jaws.

Appropriately, the apparatus is such provided, that said unit holder consists of two mu¬ tually separated shackle clamps being adapted to fix an interconnected thigh and drumstick by grasping around it, mainly from the front, at each side of the knee joint.

Advantageously the apparatus according to the invention may be such provided, that said internal tubular knife is arranged rotating in one of said displacable tube means, and that compressed air for discharging the scraped bones through the other tube means is supplied through the rotating tubular knife.

The invention is explained in more detail in the following with reference to the drawing, in which:-

Fig. 1 shows an embodiment for a deboning aggregate for an apparatus according to the invention,

Fig. 2 shows a sectional view of a deboning aggregate cf. Fig. 1,

Fig. 3 shows a pair of holding jaws for a deboning aggregate according to the invention - seen from the line πi-HΪ in Fig. 1,

Fig. 4 shows a view - partly in sections - of a detail of a deboning aggregate accor¬ ding to the invention - seen from the line IN-IV in Fig. 1,

Fig. 5 shows a view - partly in section - of a detail of a deboning aggregate according to the invention - seen from the line V-V in Fig. 1,

Fig. 6 shows a schematic side view - partly in sections - of an embodiment of a drum-shaped deboning apparatus according to the invention, and

Fig. 7 shows a schematic end view - partly in sections - of the deboning apparatus shown in Fig. 6 according to the invention,

The deboning apparatus 2 shown in Figs. 6 and 7 comprises a stationary, laying drum- shaped basic part 4 suspended on a horizontal bearing axle 6. On this bearing axle two gables 8 furthermore are pivoting arranged, between which gables 8 twelwe uniform deboning aggregates 10 (Figs. 1 and 2) are arranged, each mounted on two mutually parallel gliding rods 12. The cylinder surface of the drum-shaped basic part 4 is provided with steering recesses 14, in which steering rolls 16 or steering pins interact to be displaced along the gliding rods 12, respectively activation of the the respective parts of the deboning aggregrates.

Each deboning aggregate 10 comprises two on gliding rods 12 mutually displaceably ar¬ ranged pairs of mutually pivoting holding jaws 18, which in a non-shown manner may be displaced along the gliding rods 12 by interaction with suitable steering recesses, and which by means of steering rolls 16 and therewith co-operating tooth sectors 20 may open and close the holding jaws 18. The holding jaws 18 are mounted on gliding sockets 22.

The deboning aggregates 10 comprise a first displacable tube means 24, which is such mounted on the gliding sockets 26 that the tube means 24 itself - as shown in Fig. 3 - are placed on level with grasping parts 28 of the holding jaws 18, and another displa- cable tube means 30, which is mounted on gliding sockets 32. The tube means 30 co¬ operate with a rotating tubular knife 34, which is placed inside of the tube means 30, and which is driven via a rectangular tube 36 and a gear wheel 38. The rectangular tube 36 may via a revolving coupling 40 be connected with a telescopic pipe stub 42 (Fig. 6) for the supply of compressed air.

Furthermore each deboning aggregate 10 comprises a pivoting feeder arm 44 with an unit holder 46 preferably in form of a double spring clamp, the clamp parts of which are intended to grasp from the front around the knee joint of an interconnected thigh and drumstick, so that outer stripped end parts of the bones by swinging in the feeder arm 44 may be placed between active gripping means 28 of the holding jaws 18. Prefe¬ rably the feeder arm 44 and the unit holder 46 are used to fix the knee joint of the meat unit, until the respective tube means 24 and 30 are placed around the scraped free bone ends and are fixing these.