US2891589A

US2891589A - Feeding mechanism in barking machines

Info

Publication number: US2891589A
Application number: US590948A
Authority: US
Inventors: Leffler Nils Gustav
Original assignee: Sunds Verkstader AB
Current assignee: Valmet AB
Priority date: 1955-06-13
Filing date: 1956-06-12
Publication date: 1959-06-23
Anticipated expiration: 1976-06-23
Also published as: DE1195467B

Description

June 23, 1959 N. G. LEFFLER FEEDING MECHANISM IN BARKING MACHINES 3 Sheets-Sheet 1 Filed June 12, 1956 June 23, 1959 N. e. LEFFLER FEEDING MECHANISM IN BARKING MACHINES Filed June 12, 1956 3 Sheets-Sheet 2 June 23, 1959 N. G. LEFFLER 2,891,589

FEEDING MECHANISM IN BARKING MACHINES Filed June '12, 1956 3 Sheets-Sheet 3 2 .37 4/ J8 174/ 42 JJ 6 58 .57 62 60.565/ -53 5'9 FEEDING MECHANISM 1N BARKING MACHINES Nils Gustav Lefller, Sundsbruk, near Sundsvall, Sweden, assignor to Sunds Verkstiider Aktiebolag, Sundsbruk, Sweden Application June 12, 1956, Serial No. 590,948

Claims priority, application Sweden June 13, 1955 Claims. Cl. 144-247 In barking machines of the kind in which the log is fed into engagement with at least one debarking tool, either in a rectilinear or a rotary motion, it is of the greatest importance that the feeding means be so shaped as to feed the log effectively while causing only small or no depressions in the wood and while supporting the log obtained at the same time, such as that even crooked logsv are held in correct positions in relation to the debarking tools.

With a view to making my invention clear one embodiment thereof will be hereinafter described, reference being had to the accompanying drawings. For my description I have chosen an embodiment including also the use of the invention set forth in my aforesaid patent, yet without thereby limiting in any way the scope of my invention, the inventive idea including the possibili-, ties of using several other embodiments. I

In the drawings:

Figure 1 shows a side view of the machine.

Figure 2 shows a side view of a device, a so-called roller conveyor, serving for supporting the log and, preferably, serving also for feeding the same, said conveyor being located before and/or after the'machine.

Figure 3 shows a section taken on line 3-3 of Fig. 2.

Figure 4 shows a preferred guiding device, located before the debarking tools.

Figure 5 is a fragmentary plan view of the right-hand end of the machine seen in elevation in Fig. 1,

Figure 6 is a plan view of the guiding device shown in elevation in Fig. 4,

Figure 7 is a plan view of the left-hand end of apparatus shown in elevation in Pig. 2.

In Figure 1 the direction of feed of the log is indicated by the arrow 1. By means of a conventional chain conveyor, not shown, the log may be moved to the feeding-in mechanism of the machine, the term feeding-in mechanism being applicable to the feeding device located before the debarking tools.

The feeding-in mechanism comprises a leading roll or roller 3 mounted on an arm or fork 4, said arm or fork being swingably mounted on a shaft 5 supported by brackets secured to a frame 6. In order to obtain good centering of the log there is provided another leading roll or roller 7 mounted on an arm or fork 3, said arm or fork being swingably mounted on a shaft 9 supported by brackets, which are, likewise, secured to the frame 6. In order to make certain that the log is centered the

arms

4 and 8 may be interconnected by means of links 10, mounted on

pivots

11 and 12, said pivots being secured to the

arms

4 and 8, respectively. By choosing, in a suitable way, the positions of the

pivots

11 and 12,

the

nited States Patent the lengths of the

arms

4 and 8, the positions of the

mounting shafts

5 and 9 and the lengths of the links 10 it is possible to positively guide the rollers 3 and 7, so that their rotational axes, when in various positions that correspond to various log diameters, will be substantially situated in the same vertical plane and at the same distance from the horizontal center line of the machine.- For obtaining this effect it is, of course, possible to use other link systems.

The leading feed rollers 3 and 7 are shown to be provided with

chain wheels

13 and 14, driven by means of

chains

15 and 16 from

chain wheels

17 and 18. For obtaining the correct direction of rotation of the leading rollers 3 and 7 a cylindrical toothed wheel 19 is provided on the same shaft 5 as the chain wheel 17: and an identical cylindrical toothed wheel 19 is in en-' gagement with the first-mentioned toothed wheel and is secured to a shaft 20. To said shaft 20 a chain wheel 21 is also secured, said wheel, through the intermediary of a chain 22, driving a chain wheel 21', which is secured to the same shaft 9 as the chain wheel 18 and a thirdchain wheel 21" which serves to drive a group of yield-: able conveying rollers 59 (see Figures 2, 5 and 7), which will be later described. For the purpose of wholly orpartly counter-balancing the swinging parts a spring 23;

may be provided. Furthermore, stopping means 24- should be provided for the arm 4 so as to limit the move; ment of the arm towards the center of the log and so, as to make it possible to adjust such limit of movement.-

Theleading rollers 3 and 7 are driven to rotate'in the direction of the arrows and the power for driving the. same preferably may be supplied through the inter-,

mediary of the

shafts

5 and 9, respectively, of the chain wheel 17 or of the chain wheel 18. By means of the spring 23 the contact pressure of the two leading rollers 3 and 7 is adjusted to a suitable strength and to a value below the pressure required for 1 Said spring alsov feeding the log through the machine. may be embodied as a pressure spring, so that the pressure on leading roller 3 will increase when the spring is being strained. When the log is being introduced between the leading rollers 3 and 7 from, for example, a feeding-in conveyor there is obtained, due to the mounting of the roller or of the rollers, a power component increasing the contact pressure on the surface of the log with increasing. feeding resistance. sistance be low, the contact pressure of the rollers on the log ,will be low, Whereas if, on the other hand, the feeding resistance be high a contact pressure on the log portion ofthe leading roller 7 which is to contact the logshould be located at a somewhat higher elevation than. the lower portion of the log when the log rests on the;

feeding-in conveyor, not shown, thus making certain that the roller 7 will always be contacted by the log when the latter moves into the machine. When a certain feed-- ing resistance is exerted either by, for example, leading.

guide plates

25, 26 positioned before the barking mem-. bers 2, or by the barking members themselves, the log" will be raised to the center of the machine by the-roller 7. Such upward movement will be limited by the roller 3 and the equal but opposite movement of the two rollers will result in the logs always being constrained for atrial This means that if the feeding, re-.

movement along the horizontal axis of the machine, independently of the thicknesses of the logs.

The feeding-in mechanism of the machine having been described in detail, a description will follow of some of the other feeding and/ or guiding devices that may be combined with the feeding-in mechanism. Thus, after the feeding-in mechanism the log will meet the leading

guide plates

25 and 26, which are swingably mounted on

pivots

27 and 28 and interconnected for equal but opposite movement by means of links 29, located on both sides of the guide plates and articulated to pivots 3t} and 31. For the purpose of pressing the leading guide plates against the surface of the log springs 32 are secured either to the upper plate or to the lower plate, or to both plates, including suitable stretching means so as to provide for the required tension.

Instead of the above-described arrangement leading guide plates 33 may be provided between the feeding-in mechanism and the barking members 2, as shown in Figure 4. Since said leading guide plates 33 are mounted to move in a vertical or a substantially vertical direction, the horizontal distance between their trailing ends and the debarking tools can be kept small for all log diameters. In the embodiment according to Figure 4 this is made possible by the leading guide plates 33 being secured to beams or similar members 34, said beams or similar members being at their ends provided with sleeves 35 movable on bars 36, located on both sides of said leading guide plates. For the purpose of centering the log the sleeves 35 are, in pairs, interconnected by means of links 37 and swingable arms 38, said arms being mounted on pivots 39 secured in sleeves 39' rigid with the bars 36. At their one ends the links 37 are jointed to pivots 40 on the movable sleeves 35 and at their other ends they are jointed to the swingable arms 38 by means of pivots 41.

By means of springs 42 anchored at their upper ends to lugs on the forwardmost links 37 and at their lower ends to brackets on the frame 6, the leading guide plates 33 are held in a closed position or in a position corre sponding to the diameter of the thinnest log to be barked. When a log of a larger diameter is fed between the lead ing guide plates the latter are wedged apart by the log, each plate moving an equal distance from the horizontal center line. The log having left the leading guide plates the latter return to their closed positions, shock-absorbing plates 43 of rubber, for example, being provided to reduce the shock. It may be suitable to provide the leading guide plates with longitudinally extending fillets 63 (see Figures 1 and or similar means in order to prevent the log from being twisted by the debarking tools and/ or in order to slit open the bark along the log.

Having passed the leading guide plates, whether said plates are arranged in accordance with Figure l or Figure 4, or in some other way, the log will meet the debarking members 2, which may be supported by a rotary annular member in a 'housing 44, and will then move on to the discharge mechanism of the machine, said discharge mechanism preferably consisting of trailing rollers 3, 7, embodied in the same way as the leading rollers of the feeding-in mechanism, except that said trailing rollers 3 and 7 of the discharge mechanism (Figure l) are driven at a peripheral speed which is different from the peripheral speed at which the corresponding leading rollers of the feeding-in mechanism are driven. This will be the case if, for example, the chain wheels 45 and 46, connected with the trailing rollers 3 and 7 of the discharge mechanism, do not possess the same number of teeth as that of the

corresponding chain wheels

13 and 14 of the feeding-in mechanism. Yet the peripheral speeds of the two leading rollers of the feeding-in mechanism proper should be equal, and, likewise, the peripheral speeds of the two trailing rollers of the discharge mechanism proper should be equal, even though the peripheral speed of the discharge rollers differs from that of the feeding-in rollers.

In Figure 1 there is shown also a pair of log-supporting plates 47, 48 positioned after the discharge mechanism, said supporting plates being, fundamentally, mounted and spring-loaded in the same way as the leading

guide plates

25, 26 between the feeding-in mechanism and the debarking tools. The supporting plates 47, 48 are not necessary for the functioning of the machine, and under certain circumstances they may very well be dispensed with.

As mentioned above the log will first meet the leading rollers 3 and 7 of the feeding-in mechanism, said rollers-because of the relatively low pressure with which they are loaded in a direction towards each otherbeing easily moved apart by a log entering between them. The log will then move on and enter between the

leading guide plates

25, 26 and between the debarking tools 2. The leading

guide plates

25, 26 preferably are positioned very close to said tools. The device shown in Figure 4 offers the advantage that the trailing ends of the leading guide plates 33 can be located closer to the tools 2 than can the trailing ends of the

leading guide plates

25, 26 of Figure 1.

The log having entered between the tools 2 the barking is started. The leading guide plates 25, 26 (or 33) maintain the log centered with respect to a vertical and horizontal path along the center line of the machine at the debarking tools. This is made possible by the log being held against radial shifting at only one place before said leading guide plates; in Figure 1 this is done by the leading rollers 3 and 7 of the feeding-in mechanism.

The log having reached the discharge mechanism, shown to the left in Figure 1, it will enter between the trailing rollers 3 and 7 thereof, which rollers, as already mentioned, should be driven at a different peripheral speed than that at which the corresponding leading rollers of the feeding-in mechanism are driven. In such a case two alternatives are possible, viz. either the pheripheral speed of the first-mentioned rollers is lower than that of the last-mentioned rollers, or vice versa.

If, in accordance with the first alternative, the peripheral speed of the trailing rollers of the discharge mechanism is lower than that of the leading rollers of the feeding-in mechanism, the trailing rollers of the discharge mechanism will, of course, normally not take part in the feeding of the log and no contract pressure, caused by the feeding resistance, will be obtained. By balancing in a suitable way the swingable parts, by a suitable choice of springs, by adjusting the difference between the peripheral speed of the leading rollers of the feedingin mechanism and that of the trailing rollers of the discharge mechanism et cetera there can be obtained between the trailing rollers and the log a contract pressure which is so small that the log will not be centered at the discharge mechanism. In this case the feeding and centering of the log will continue in the same way as before the log entered between the trailing rollers of the discharge mechanism, i.e. the log was vertically and horizontally centered quite close to the debarking tools by the leading guide plates and, in addition was held against radial shifting by the leading rollers of the feeding-in mechanism, said leading rollers alone providing for the feeding.

Since logs often are crooked the effect obtained is obvious. A crooked log becomes Well centered at the barking members, which would not be possible if the log were held against radial shifting both between the pair of leading rollers of the feeding-in mechanism and also between the pair of trailing rollers of the discharge mechanism.

The rear end of the log having left the feeding-in mechanism the discharge mechanism automatically will take over the feeding, and good centering is still obtained because the log remains in contact with the leading guide plates, and is held against radial shifting at only one place, namely between the pair of trailing rollers of the discharge mechanism.

This embodiment, in which the peripheral speed of the trailing rollers is lower than that of the leading rollers, provides a further advantage, when the logs have thick bark. Since the initial feeding is effected by spikes or similar members on said leading rollers being pressed into the thick bark of the log, no indentations will be produced in the underlying Wood surface before the log reaches the debarking members, because the thick bark forms a protective layer. Thus the debarking tools, as they remove the bark, will have a smooth underlying Wood surface on which to ride; and any indentations caused by the discharge rollers, when they take over the feeding, can not affect the quality of the debarking operation.

If the peripheral speed of the trailing rollers of the discharge mechanism is higher than that of the leading rollers of the feeding-in mechanism, then the feeding-in mechanism will hold the log against radial shifting and will feed the log only until the log reaches the discharge mechanism, after which the latter mechanism will automatically take over the feeding, the log still being centered at the barking tools, even if the log be crooked, because besides being vertically and horizontally centered by the leading guide plates the log is held against radial shifting only by the trailing rollers of the discharge mechnism, said trailing rollers alone effecting the feeding.

The last-described embodiment provides further advantages when the logs have thin bark. Since the feeding of most of the log is effected by the pair of trailing rollers of the discharge mechanism, the spikes, or similar portions, of said trailing rollers will be pressed into the bare wood of the barked part of the log, and thus no bark will be pressed into the wood. Also, since any indentations or depressions made in the wood by the spikes, occur after the log leaves the debarking tools, a finer log surface without any wood damages will be obtained, there being no depressions or markings which would cause the barking tools to tear the wood.

It has been assumed in the two alternative embodiments just described, that the logs at any given instant are swingably supported by only one of the feeding means, and are vertically and horizontally centered by means of the leading guide plates. If, however, for example due to swellings on the log or due to the log being crooked, the feeding resistance should become so high that the spikes of that pair of rollers rotating at the higher peripheral speed would slide relatively to the log, resulting in the speed of feed falling below the peripheral speed at which the other pair of rollers (those rotating at a lower peripheral speed) are driven, then it follows that both of the feeding mechanisms will take part in the feeding. This will prevent such log becoming stuck in the machine, and the machine will revert to the previously described manner of operation as soon as the abnormal and usually momentarily high feeding resistance has been overcome.

In order to facilitate the perfect functioning of the machine, those rollers, which rotate at the lower peripheral speed, may be driven so that they can also be driven freely by the log at a higher peripheral speed than that obtained from the driving means. In the embodiment according to Figure 1 this result can be obtained, if the rollers rotating at the lower speed be driven through the intermediary of an overrunning clutch or a so-called free-wheel. Such an arrangement, which may be similar to that disclosed in my copending application Serial No. 409,912, filed February 24, 1954; now Patent No. 2,774,319, dated December 18, 1956, may be built into the

chain wheels

13, 14 and 45, 46, respectively. Then the rollers rotating at the lower peripheral speed will not brake the feeding of the log, but the log will be driven by those rollers rotating at the higher peripheral speed.

Although the supporting plates 47, 48-which are located after the discharge mechanism when looking in the direction of feed of the loghave been shown to be shaped in about the same way as the

guide plates

25, 26 they may, preferably, be shaped in such a way that they do not in the same manner as the last-mentioned guide plates guide the log but only support the latter (see Fig ure 1). In place of the supporting plates 47, 48, it may be desired to provide one or more conical conveying rollers 49, which are spring-loaded preferably towards the center line of the machine, said rollers, on one hand, preventing the log from jerking during the last part of the barking operation, i.e. when the log has left the

guide plates

25, 26, and, on the other hand, serving to provide a yieldable support for the log. This arrangement permits a smaller contact pressure by whichever pair of leading guide plates 25, 26 (Figure 1) or 33 (Figure 4) are used, such contact pressure being predetermined by the tension in either the

springs

32 or 42. It is also desirable to provide such spring-loaded conveying rollers before the machine where they will also serve to yieldably support the log. If several such yieldable conveying rollers be provided on both sides of the means for feeding and guiding the log, then the log may be more easily conveyed with its center line coinciding with the center line of the machine.

These groups of conveying rollers, before and after the machine, may, in point of principle, be arranged in one and the same way and therefore only one of them will be described, for example, the group located before the machine, and shown in Figures 2 and 3. Thus, when the log to be barked is fed over said conveying rollers 49, said rollers will be swung downwards, so that the center line of the log, at least when the log meets the leading rollers, 3 and 7, will substantially coincide with the center line of the machine. This is made possible by the con veying rollers 49 being swingably mounted in yokes 59 on shafts 51 and by the provision of springs 52, said springs being so adjusted and so located relatively to the yokes 50 that a suitable upward pressure will be obtainedso as to produce the above indicated effect. The shafts 51 are supported by hearing members 53, secured to the frame 54. In order to limit the upward and down ward movement of the conveying rollers 49 there are provided bumpers 55 on the yokes 50 for reducing the shocks on abutments or brackets 62 arranged on the frame 54. Preferably, the conveying rollers 49 are driven from the barking machine in such a manner that they cause the feeding of the log to the machine, and in the drawing it is indicated that the driving takes place from the chain wheel 21 by means of

chain wheels

56 and 57, said

chain wheels

21, 56 and 57 being interconnected by means of

chains

58, 59 and 60. Before the group of conveying rollers 49 shown in Figure 2, is located a conventional chain conveyor 61.

Of course it is not possible to adjust the springs 52, which yieldably support the conveying rollers 49, so that logs of all dimensions will be kept on exactly the same center line, because the logs do not, for example, possess the same specific gravity. But the idea of using yieldably supported conveying simple and results in a lower pressure on the log surface (upwards or downwards) by either the feeding-in mechanism or the discharge mechanism and by the leading guide plates 25, 26 (or 33). If the conveying rollers 49 did not yieldably support the log, they would prevent the previously described centering of the log close to the debarking tools.

The invention has now been described in connection with an embodiment of the machine, in which the axial feeding resistance of the log is of importance.

It should also be pointed out that the machine according to the embodiment shown in Figure 1 may be embodied in such a way as if said figure showed a plan view instead of showing a side view, as is now the case. Furthermore, the machine may be turned upside down, so that the rollers 3 will be located at the underside of the log.

In addition to the above-described advantages vobtained by the present invention and which make possible the barking of a log with little or no damage to the wood, the invention also results in an increase of the capacity of the machine. Due to the centering of the log close to the debarking tools it is possible, when said tools are revolved by rotation of the rotary annulus in the housing -4;, to rotate said annulus at a considerably higher speed than would otherwise be possible in this type of machines, and yet maintain the quality of the marking.

Having now described my invention, what 1 claim as new and desire to secure by Letters Patent is:

1. A log-feeding mechanism including log-infeeding and log-outieeding mechanisms for a barking machine of the kind provided with at least one barking tool movable into and out of engagement with a log being fed through the machine, and in which machine either the barking tool or a log being fed, is rotatable relatively to the other; said log-infeeding mechanism being provided with nonfeeding means for guiding a log being fed,

means of said loginfeeding mechanism being positioned in advance of said nonfeeding-and-guiding means.

2. A iog-feeding mechanism as recited in claim 1, wherein said higher-speed feeding-and-holding means constitutes part of said log-infeeding mechanism.

3. A log-feeding mechanism as recited in claim 1, wherein said higher-speed feeding-holding means constitutes part of said log-outfeeding mechanism.

4. A log-feeding mechanism as recited in claim 1,

wherein said lower-speed feeding-andholding means takes part in the feeding of a log, whenever resistanceto-feeding of a log causes said higher-speed feeding-andholding means to slip over the surface of such log.

5. A log-feeding mechanism for a barking machine of the kind provided with at least one barking tool movable into and out of engagement with a log being fed through the machine, and in which machine either the barking tool or a log being fed, is rotatable relatively to the other, said feeding mechanism being provided with nonfeeding s for guiding a log being fed, said nonfeeding and guiding means contacting such log close to the barking tool, a feeding-and-holding means for a log being positioned in advance of said nonfeeding and guiding means and another feeding-and-holding means for a log being positioned after said nonfeeding and guiding means, said two feeding-and-holding means being arranged in such a way that normally only one of them at a time automatically feeds and holds the log, even when the lattcr has reached both of them, while the other permits the log to move in any radial direction.

References {fitted in the file of this patent UNITED STATES PATENTS 1,943,649 White et a1. Ian. 16, 1934 1,957,792 McManis May 8, 1934 2,448,689 Schnyder Sept. 7, 1948 2,646,092 Kolpe et al. July 21, 1953 2,694,425 Skoglund Nov. 16, 1954 2,774,397 Leffier Dec. 18, 1956 2,779,363 Laughton Jan. 29, 1957 2,794,466 .efiier a June 4, 1957 2,815,776 Annis et al. Dec. 10, 1957 2,821,220 Nicholson Jan. 28, 1958 FOREIGN PATENTS 146,958 Sweden Sept. 14, 1954