WO1995011117A1

WO1995011117A1 - Butt reducing machine

Info

Publication number: WO1995011117A1
Application number: PCT/SE1994/000918
Authority: WO
Inventors: Bengt TANNERSTÅL
Original assignee: Tannerstaal Bengt
Priority date: 1993-10-22
Filing date: 1994-10-03
Publication date: 1995-04-27
Also published as: SE9303482L; AU7952194A; SE501065C2; SE9303482D0

Abstract

A butt reducing machine comprises axially spaced-apart support means (12, 13) which together form a support on which logs (7) may be placed in a position in which a butt end part (7') protrudes into the region above a mill (8), at the same time as a top end part (7'') is kept pressed against the support by a holding means (4) on an elevating carrier (3). The holding means (4) comprises two axially spaced-apart pressing members (17, 17') mounted on a common frame structure (18) which is pivotably connected to the carrier (3) in order to enable a simultaneous, flexible pressing of the two members (17, 17') against the log, independently of the shape of the log. The distance between the pressing members (17, 17') is somewhat smaller than the distance between the support means (12, 13) located next to the mill, whereby the pressing members are located in planes closely inside said support means (12, 13) during their contact with the log.

Description

BUTT REDUCING MACHINE

Technical Field of the Invention

The present invention relates to a butt reducing machine comprising a number of axially spaced-apart support means which together form a support on which logs may be placed in a position in which on one hand a butt end part of the individual log protrudes freely from the support in order to be machineable by a mill and on the other hand a top end part may be kept pressed against the support by a holding means carried by an elevating carrier, the log being submitted to a rotation while the butt end part is simultaneously milled.

Prior Art

Butt reducing machines of the art generally described above are previously known by SE 7712493-1 and SE 8203956-1. The basic task of this type of machines is to mill off the root swellings that occur on the butt end part of the log before dividing in a sawmill, so that these swellings shall not cause any problems during the subsequent handling in the sawmill. In this milling machining it is essential, that not only ideally formed straight logs, but also crooked and/or non-circular logs are machined in such a way that on one hand undesired root swellings are removed in an efficacious way and on the other hand a good yield is achieved, i.e., the machined log leaving the machine shall have a substantially cylindrical butt end part the diameter of which is not smaller than that of the top end part. However, in this respect the previously known machines have left less good results, particularly in connection with the machining of crooked and/or non-circular logs which when placed upon the support and submitted to a rotation, tend to get a wobbling and swinging motion rather than a distinct rotative motion around one and the same axis of rotation during the whole milling operation. The reason for this is to be found in the holding means which keeps the log urged or pressed against the support. According to SE 7712493-1 the holding means consists of a yoke with a driver chain, the yoke being mounted at the free, vertically adjustable end of a pivoting arm construction. According to SE 8203956-1, the holding means consists of a pair of rolls which are mounted freely rotatably at a V-shaped pressing means, which in turn is pivotably supported at the free end of a turning arm. In both of these cases, the holding means are placed in immediate proximity to the support means being closest to the mill, more precisely on the side of the support means being opposite to the mill. This means that the top end part of the log is firmly pressed against the support during the rotation only at one point which, furthermore, is situated at a short distance from the support means next to the mill.

Therefore, when the machine handles logs which present large root swellings and which at the same time are crooked and/or non-circular, it happens that the holding means is unable to hold the top end part of the log distinctly pressed against the support. The result of such an insufficient pressing of the log against the support is that the log tends to swing, whereby too much material will be milled away from the butt end part (in the extreme case, the latter becomes point-shaped or tapered).

Theoretically, it would be feasible to improve the pressing of the top end part against the support by placing the holding means about half-way between the two support means being next to the mill, but in such a case every log that is crooked in its portion between these support means would be set into a bouncing motion at its butt end part, or alternatively get stuck between the holding means and the support.

Objects and Characteristics of the Invention

The present invention aims at removing the above mentioned inconvenience of previously known butt reducing machines and providing a machine that gives both an efficacious milling-away of undesired root swellings and a good yield of the log. Thus, a primary object of the invention is to provide a machine that holds the top end part of the log distinctly pressed against the support in order to eliminate any tendency of bouncing or swinging motions of the butt end part during the milling operation. According to the invention, this object is attained by the features as defined in the characterizing clause of claim 1. Furthermore, preferred embodiments of the invention are defined in the dependent claims.

Brief Description of the Appended Drawings

In the drawings

FIG. 1 is a schematic side view of the machine according to the invention,

FIG. 2 is a plane view of the machine according to figure 1 seen from above,

FIG. 3 is an enlarged side view of the holding means included in the machine, and

FIG. 4 is a cross sectional view along line A-A in figure 3. Detailed Description of a Preferred Embodiment of the Invention

The machine shown in figures 1 and 2 comprises a lower frame 1, a stand 2 provided at one end of the frame, a carrier designated by reference numeral 3 in its entirety, in the form of a swinging arm construction which at its free end carries a holding means generally designated by 4, a number of support means 5, 5', 5", etc, which jointly form a support for

supporting a log 7. In the example shown, the individual support means 5, 5', 5", etc, consist of vertical plates which are connected to frame 1 in a suitable manner. In connection with the support formed by the support plates, although spaced-apart therefrom, a mill generally designated 8 is arranged, which has the purpose of machining the butt end part 7' of the log

protruding from the support. According to the example shown, the mill 8 is rotatably mounted on a pivotable underbody 9 which also carries an electric motor 10 for driving the mill.

Support plates 5, 5', 5", etc, are formed with V-shaped recesses 6 (see figure 4) at their upper edges, for receiving the log 7 in a centered position relative to the machine frame. In practice, the log may be brought in over the support from the side by a suitable cross conveyor (not shown) . When the

machining has been finished, the log is removed from the support by special expulsion means 11 arranged in connection to at least some of the support plates.

In connection with the two support plates 5, 5' being located next to mill 8 carrying wheels 12, 12' and 13, 13' respectively, are arranged in co-operating pairs, against which the log will abut when it falls down into the upwardly open V-recesses of support plates 5, 5'. Carrying wheels 12, 13 and 12', 13' are fixed on common shafts 14 which may be driven via suitable transmissions 15 by a common driving source, for instance an electric motor. By these carrying wheels cooperating in pairs, which contact the log from below, at least a share of the power required for bringing the log to rotate around its own axis and relative to the mill 8, may be conferred to the log. It should be noticed that carrying wheels 12, 12' and 13, 13' themselves form the active support means upon which the log rests during rotation, in that the wheels, as may be seen in figure 4, partially protrude upwardly above the upper edges of support plates 5, 5' in the vicinity of the V-recesses 6.

So far, the described machine is substantially previously known.

According to the invention, holding means 4 comprises two axially spaced-apart pressing members 17, 17' which are mounted on a common frame structure 18 being, via a main pivot 19, hingedly connected to the swinging arm construction 3 serving as a carrier. As clearly shown in figure 1, the distance between these two pressing members 17, 17' is smaller than the distance between the two wheel pairs 12, 12' and 13, 13' serving as active support means, so that the pressing members become located in vertical planes situated inside these wheel pairs. However, the distance between the pressing members is only slightly smaller than the distance between the supporting wheel pairs, whereby the vertical planes in which the pressing members operate become located next to the supporting wheel pairs. In practice, the axial distance between the supporting wheel pairs may be within the range of 800 to 1300 mm at the same time as the distance between the pressing members 17, 17' lie within the range of 600 to 1100 mm. According to an embodiment of the machine projected in practice, the distance between the wheel pairs 12, 12' and 13, 13' is 1050 mm at the same time as the distance between the pressing members 17, 17' is 750 mm, implying that the individual pressing member will operate in a vertical plane situated about 150 mm inside the associated supporting wheel pair.

As may be seen in figure 2, the swinging arm

construction 3, which serves as a carrier, comprises two spaced- apart, parallel arms 20, 20', being interconnected via a cross piece 21 and being hingedly connected to stand 2 via pivots 22 at the ends being distant from the holding means. A standard 23 is stiffly connected to the frame structure 18 of the holding means, said standard being, via a first pivot 24, connected to a bar 26 which is pivotably movable relative to the stand via a second pivot 25, said bar having the purpose of keeping the frame structure of the holding means in a substantially

horizontal position independently of the level adjustment position of holding means 4. The swinging arm construction 3 is pivotable by means of a hydraulic cylinder 27 connected to cross-piece 21. When lifting or lowering the free end of the swinging arm construction, pivots 19, 24, 25 and 22 form a parallelogram steering which guarantees that the frame structure of the holding means is always held in a substantially

horizontal position. However, in order to allow for a certain movability of said frame structure when machining uneven and/or crooked logs, pivot 24 is movable along bar 26 against the action of springs 28, 28', which on one hand always strive to move the pivot to a given position along the bar, and on the other hand yield to the forces arising when the frame structure and standard 23 tend to turn around main pivot 19.

As may be seen in figure 4, standard 23 comprises two separate plates 29, 29' between which a turnable sleeve or ring 30 with a through-hole for the bar 26 extends. Springs 28, 28', which advantageously consist of coil-pressure springs, are arranged between pairs of cap sleeves 31, 31'; 32, 32', of which the two middle ones, being in contact with turnable sleeve 30, are freely movable relative to the bar, while the two other cap sleeves 31', 32' have the shape of internally threaded nuts which are in engagement with externally threaded parts of the bar. By these outer cap sleeves or cap nuts 31', 32', the tension in springs 28, 28' can be regulated. In this context it should also be noticed that the bar is composed of on one hand a pipe 33 and on the other hand two rods introduced into the opposed ends of the pipe, the position of the rods relative to the pipe being determined by stop-nuts 35. With these stop-nuts 35, it is possible to vary the length of each rod that protrudes from the adjacent pipe end, and in this way, also the distance between the pivots 24, 25.

As may be further seen in figures 3 and 4, each one of the two pressing members 17, 17' consists of a pair of cooperating, rotatable rolls 36, 37 and 36', 37' respectively (of which the latter is hidden behind roll 36' in figure 4). All these rolls are drivable in one and the same direction of rotation in order to confer a rotative motion to log 7 when pressed against the same together with driving and support wheels 12, 12'; 13, 13'. According to the shown embodiment, the two driving rolls 36, 37 of one pressing member 17 are co-rotatively connected to corresponding driving rolls 36', 37' of the other member, more specifically by analogous rolls in the two members being placed on common shafts 38 (of which only one is visible in figure 3), which in turn are drivable by a common driving source 39 in the form of a hydraulic motor via a

transmission which, according to the shown example, is a chain 40 laid around sprockets being connected to the driving rolls, a sprocket being connected to the output shaft of motor 39, and a breaking wheel.

As seen in figure 4, the main pivot 19 between the frame structure 18 of the holding means and the free ends of the two arms 20, 20' of the swinging arm construction is formed by taps 41, 41' which are located at side members protruding downwardly from the frame structure and engage into holes in the free ends of the arms.

The machine operates in the following way. The individual log 7 is rolled in upon the support formed by support plates 5, 5', 5" in such a way that a butt end part 7' will protrude from the support in the area obliquely above the mill 8 at the same time as a longer top end part 7" rests upon a number of support members that varies depending on the length of the log. After the introduction of the log upon the support, holding means 4 is brought downwardly, towards the upper side of the log by activating the hydraulic cylinder 27, by which the driving rolls 36, 37, 36', 37' of holding means 4 are brought to be pressed against the log, more specifically at points being located immediately inside the two wheel pairs 12, 12'; 13, 13' which form the two active support members next to the mill 8. When the log is set into rotation by both the driving rolls of the holding means and the driving wheels of the support being brought to rotate by motors 39 and 16, respectively, then its top end part will be kept distinctly pressed against the two pairs of driving wheels 12, 12'; 13, 13', more specifically at points located close to the associated pairs of driving wheels. In this way, the log will be given a rotation along a fictive geometrical, longitudinal axis the position of which will not be considerably altered even if the log would be crooked in its part located between the carrying driving wheels. In this way, it is guaranteed that the butt end part 7 ' of the log is

relieved from undesired root swellings without any excessive milling, i.e., without the butt end part being given a more or less pronounced conical form by unintentional wobbling motions. Feasible Modifications of the Invention

It is evident that the invention is not limited to the embodiment described and shown in the drawings. Thus, it is for instance possible to form the two pressing members comprised by the holding means in another way than in the form of drivable wheels arranged in pairs. Moreover, it is conceivable to use any other, arbitrary elevating carrier for the holding means instead of just a swinging arm construction. Further, it is pointed out that the machine according to the invention may by equipped with more than one mill, more specifically with a complementary mill located in the area between the pairs of support wheels 12, 12'; 13, 13' in order to remove, when necessary, also such

unevennesses that occur on that part of the log which is

positioned in the area between said wheels.

Claims

1. A butt reducing machine comprising a number of axially spaced-apart support means which together form a support on which logs may be placed in a position at which on one hand a butt end part (7') of the individual log (7) protrudes freely from the support in order to be machineable by a mill (8) and on the other hand a top end part (7") may be kept pressed against the support by a holding means (4) carried by an elevating carrier (3), the log being submitted to a rotation while the butt end part is simultaneously milled, c h a r a c t e r i z e d in that the holding means (4) comprises two axially spaced-apart pressing members (17, 17') mounted on a common frame structure (18) which is pivotably (19) connected to the carrier (3) in order to enable a simultaneous, flexible pressing of the two members (17, 17') against the log (7) independently of its shape, the distance between the pressing members being smaller, although only slightly smaller than the distance between the two support means (12, 12'; 13, 13') of the support being located next to the mill (8) , whereby the pressing members (17, 17') are located in planes closely inside the latter support means during their contact with the log (7).

2. Machine according to claim 1, c h a r a c t e r i z e d in that each one of the two individual pressing members (17, 17') comprises a pair of co-operating, rotatable rolls (36, 37; 36', 37') which are drivable in one and the same direction of rotation in order to actively confer a rotative motion to a log (7), when pressed against the same.

3. Machine according to claim 2, c h a r a c t e r i z e d in that the two driving rolls (36, 37) in one (17) of the pressing members is co-rotatively connected to the driving rolls (36', 37') of the other member (17'), more specifically by analogous rolls in the two members being fixed on common shafts (38) which in turn are drivable by a common driving source (39), for instance a hydraulic motor, via a transmission (40).

4. Machine according to any one of the preceding claims, in which the carrier consists of a swinging arm

construction (3) which is pivotably connected to a stand (2), said construction comprising two interconnected, and thereby jointly movable, arms (20, 20') which at their free ends are pivotably connected to the holding means (4) via a main pivot (19), c h a r a c t e r i z e d in that a standard (23) is stiffly connected to the frame structure (18) of the holding means (4), which standard is connected via a first pivot (24) to a bar (26) which is pivotably movable relative to the stand (2) via a second pivot (25), said bar having the purpose of keeping the frame structure (18) of the holding means in a substantially horizontal position independently of the level adjustment position, said first pivot (24) being movable along the bar against the action of springs (28, 28') which on one hand always strive to move the pivot to a given position along the bar and on the other hand yield to the forces arising when the frame structure and the standard tend to turn around the main pivot (19) between the frame structure and the swinging arm

construction when the pressing members (17, 17') are kept pressed against a non-circular and/or crooked log.

5. Machine according to claim 4, c h a r a c t e r i z e d in that means (31', 32') are connected to the bar (26) for variably adjusting the tension of the springs (28,

28').

6. Machine according to claim 4 or 5, c h a r a c t e r i z e d in that the bar comprises means (35) for varying the distance between said first and second pivots (24, 25).