The present invention relates to a feeding apparatus for advancing pieces against a fixed stopper, particular¬ ly a feeding apparatus for advancing pieces to be spliced on a timber splicing line to a milling mechanism, said feeding apparatus comprising one or a plurality of rotatable rolls for feeding or advancing the piece to be handled.

In this type of prior known splicing line feeding equip¬ ment, the feeding elements comprise rubber-coated rolls which are rotated by means of brake motors. Thus, the movements of pieces to be advanced are ac- acomplished by alternately starting and shutting down a brake motor. On the one hand, this type of line is relatively expensive and, on the other, the splicing of rather short pieces thereby is not economically feasible due to the slow line speed.

An object of the invention is to provide an economical¬ ly feasible feeding apparatus which can be profitably operated also in connection with short pieces.

According to the invention, this object has been re¬ solved in a manner that a roll or rolls are driven continuously, and that for each roll there is a power unit for carrying the roll towards or away from a piece to be handled.

In addition, the invention provides such an arrange¬ ment that the power unit of each roll is controlled independently. The power unit is preferably a pneumatic cylinder for providing an extremely short reaction time. A pneumatic cylinder can also be controlled

readily and accurately by means of per se known equip¬ ment. -If major forces are involved, it is also possible to use a hydraulic cylinder. The power unit can simul¬ taneously move one or a plurality of rolls according to the position of the power unit for directing a divergent force through the action of the roll to a piece being handled.

According to the invention, the roll is driven by an electric or hydraulic motor, preferably at a constant speed of rotation, each motor preferably also rotating at least two rolls at the same time. For varying the feeding rate, the rolls can be arranged to have unequal diameters.

The invention will now be described in more detail and by way of an example with reference made to the accom¬ panying drawings, in which:

fig. 1 shows a schematic side view of a feeding appa¬ ratus of the invention in a first embodiment.

Figs. 2 and 3 are schematic side views of a feeding apparatus of the invention in a second and a third embodiment.

A feeding apparatus shown in fig. 1 is intended for supplying a milling mechanism with pieces to be spliced on a timber splicing line.

Reference numeral 1 indicates a body portion, the upper portion thereof being provided with a set of conveyor rollers 2 for carrying pieces (not shown) to be handled. The body portion 1 comprises two sections and between its sections 1a and 1b is fitted a vertically recipro-

eating milling mechanism 3 provided with a cutter blade 4 for cutting the necessary splice joint profiles in both ends of the pieces. The pieces to be worked are carried across the body portion from right to left in fig. 1.

Above the set of conveyor rollers 2 at body section 1a there are two rolls 5, 6 having a smooth steel surface, both rotated through the action of e.g. belts or chains 7 by an electric or hydraulic motor 8. Rolls 5, 6 are journalled pivotably relative to the centre axis 9 of motor 8, said roll 5 being provided with a power unit 10 and roll 6 with a power unit 11 for carrying rolls 5, 6 towards or away from set of rollers 2 or a piece to be worked for initiating or stopping a feeding cycle, respectively.

Rolls 5, 6 are driven continuously and usually at a constant speed of rotation. Power units 10, 11, which are preferably pneumatic cylinders, are used for bring¬ ing rolls 5, 6 together or separately into or respective¬ ly out of contact with a piece to be worked.

It should particularly be noted that roll 5, 6 can be shifted by means of power unit 10, 11 in a stepless manner relative to a piece to be worked for thus affect¬ ing the friction force between the roll and the piece.

Reference numeral 12 indicates lateral buffers, whereby a piece pushed by rolls 5, 6 against a stopper (not shown) aligned with cutter blade 4 can be shifted against a lateral stopper 13, whereafter overhead rams 4 immobilize the piece for the duration of the end work¬ ing effected by milling machine 3.

Above the set of conveyor rollers 2 at body section 1b there are substantially all the same elements and the same construction as those at body section 1a, the equivalent components being indicated with the same reference numerals, however, with an inverted comma added to those at body section 1b. The most signifi¬ cant difference is that the rotating direction of roll 6' (the left-hand roll in fig. 1) is reversed e.g. by means of a crossed belt or a gear 7" relative to that of other rolls 5, 6 and 5". In addition, between rolls 5' and 6 ' is fitted e.g. a photoelectric cell (not shown) for detecting a passing piece.

Power units 10, 11, 10', 11' are controlled by means of an apparatus indicated by reference A, whose construc¬ tion need not be described in this context as ^" it can be considered completely prior known.

The operation of a feeding apparatus used on a timber splicing line proceeds as follows.

A piece to be worked is brought into the feeding appa¬ ratus from the right in fig. 1. The piece may reach the region of roll 5 at a speed higher than the periph¬ eral speed of roll 5, whereby there is skidding between roll and piece until the speed of a piece has deceler¬ ated to match the peripheral speed of roll 5. The re¬ lative skidding between a piece and roll 5 can be ar¬ ranged by means of the adjustment of power unit 10 in such a manner that, when the question is about heavy pieces, the skidding does not stop until roll 6 engages the piece. With light pieces the skidding can come to a virtually immediate stop.

Slowing down the traveling speed of a piece can also be effected in a manner that initially roll 5 reduces the speed of a piece to match its own peripheral speed. Then roll 6, which can be smaller in diameter or which can be driven at a lower speed of rotation, reduces further the speed of a piece.

The purpose of slowing down the speed of a piece is to prevent the end of a piece from damaging upon its im¬ pact against the stopper.

Upon the impact of a piece against the stopper, or possibly slightly prior to that, roll 5 is hoisted up or at least the pressure applied thereby to a piece is relieved. Following the impact, the piece may bounce slightly backwards from the stopper and this is correct¬ ed by allowing roll 6 and/or 5 to rotate for a certain period of time for pressing the piece tightly against the stopper. Also the compressive force of"the roll ca be slightly reduced at the same time. By virtue of their smooth steel surface, the rolls do not inflict serious surface defects on the pieces to be worked even if there were some relative skidding between roll and piece.

After bringing the piece tightly against the stopper and, possibly, roll 6 and/or 5 also applying a light pressure upon the piece, lateral buffers 12 force the piece against a lateral stopper 13 whereafter overhead rams 14 immobilize the piece for the duration of work¬ ing of the end of a piece effected by milling mechanism 3.

After the working is completed, the stopper descends, overhead rams 14 and lateral buffers 12 release their

grip and rolls 5, 6 and 5 ¹ are depressed, the piece advancing from right to left in fig. 1 until a photo¬ electric cell between rolls 5' and 6' confirms that the piece has passed this particular point. Thus, roll 6' descends, stops the piece and feeds it in the opposite direction, from left to right in fig. 1, to¬ wards a second stopper jutting out at milling mechanism 3.

The feeding motion applied by roll 6' to a piece can be decelerated by adjusting power unit 10' of roll 5' in a manner that roll 5' applies a light pressure against a piece and thus produces an oppositely directed force.

After a piece has pushed itself to the stopper, roll 5" is hoisted completely off while roll 6' continues, possibly in relieved condition, compressing the piece against the stopper in order to eliminate possible bouncing.

This is followed by immobilizing the piece by means of lateral buffers 12' and overhead rams 14' and working of the end is effected by milling mechanism 3.

After this, the lateral buffers 12' and overhead rams 14' release the piece, roll 5' is descended for feeding the piece from right to left in fig. 1 to the next oper¬ ation.

The second embodiment of a feeding apparatus illustrated in fig. 2 differs from that of fig. 1 in the roll arrange¬ ments mounted downstream of milling mechanism 3 in the through-put direction of a splicing line, in other words within the region of body section 1b.

In fig. 2, a left-hand roll 5" rotates in the same di¬ rection as roll 5'. Between rolls 5' and 5" is fitted a roll 15 which is driven by roll 5' through the action of a crossed belt 16 in the opposite direction relative to rolls 5' and 5". A power unit 17 for roll 15 is mounted below the set of rollers 2. In fig. 2, the operation of roll 15 corresponds to the action of roll 6' in fig. 1. Roll 5" serves as an extra feeding roll.

Fig. 3 illustrates a third embodiment of the feeding apparatus which differs from that of fig. 2 in that roll 15 is replaced with a roll 18. In its descended po¬ sition, roll 18 is entirely below the top level of set of rollers 2. Rolls 5" and 18 are connected together in a manner that a power unit 11" moves both rolls simultaneously. Roll 5" drives through the action of an array or a chain 19 a roll 18. When power unit 11' is used to hoist up the rolls 15" and 18, the piece is pressed against rollers 20 and roll 18 carries the pice towards right in fig. 3.