US2692623A

US2692623A - Debarking machine having bark-removing members yieldably connected to centrifugally-actuated weights

Info

Publication number: US2692623A
Application number: US277784A
Authority: US
Inventors: Leffler Nils Gustav
Original assignee: Svenska Cellulosa AB
Current assignee: Svenska Cellulosa AB
Priority date: 1951-03-22
Filing date: 1952-03-21
Publication date: 1954-10-26
Anticipated expiration: 1971-10-26

Description

Oct. 26, 1954 N. G. LEFFLER 2,692,623

DEBARKING MACHINE HAVING BARK-REMOVING MEMBERS YIELDABLY CONNECTED TO CENTRIFUGALLY-ACTUATED WEIGHTS 2 Sheets-Sheet 1 Filed March 21, 1952 INVENTOR ATTORNEYS Oct. 26, 1954 LEFFLER 2,692,623

DEBARKING MACHIN AVING BARK OVING MEMBERS YIELDABLY CENTRIFUGAL -ACTUATED WEIGHTS 2 Sheets-Sheet 2 CONNECTED Filed March 21, 1952 Patented Get. 26, 1954 DEBARKING MACHINE HAVING BARK-RE- MOVING MEMBERS YIELDABLY CON- NECTED TIO CENTRIFUGALLY-ACTUATED WEIGHTS Nils Gustav Lefller, Sundsbruk, near Sundsvall,

Sweden, assignor to Svenska Cellulosa Aktiebolaget, Stockholm, Sweden Application March 21, 1952, Serial No. 277,784

Claims priority, application Sweden March 22, 1951 7 Claims.

The present invention relates to improvements in barking machines of the kind having at least one bark-removing member movable towards and away from the surface of the log and in which the bark-removing member is adapted to rotate around the log. The invention substantially resides in the following combination: -A rotary drum having at least one bark-removing member, which is held resiliently pressed against the log and which is so shaped and/or so adjusted relatively to the end of the log that, upon rotation of the drum, the barking member, or members, will climb onto the log; a counter-poise weight elastically connected to the bark-removing member and creating the contact pressure of the bark-removing member against the log under the influence of the centrifugal force generated upon rotation of the drum; a spring or a similar member acting substantially against the direction of the centrifugal force and which is adjusted in such a way that a suitable pressureis attained for various log diameters and which preferably is adjusted in such a manner that the pressure between the bark-removing member and the log will increase with the outward movement of the bark-removing member. In other words, it will increase in the direction away from the center of the drum, and a greater pressure will be obtained on thick logs which have greater peripheral speed than smaller logs for a constant number of revolutions per minute ofthe drum. Another advantage is that the bark-removing members tend to keep the log at the center of the drum by which better barking will be obtained.

The invention will be described below with reference to the accompanying drawings.

Figure 1 shows an end View of one of the barkremoving members.

Figure 2 shows a side view of the same.'

Figure 3 illustrates an alternative embodiment for the scraping edge of the barking member.

Figure 4 is a fragmentary View in end elevation of the barking machine showing the drum, the barking member and the eccentric weight mechanism, the latter being shown in section.

Figure 5 is a plan view of the machine illustrated in Fig. 4.

Figure 6 is a transverse section on line 6-6 through the interior of the barking machine shown in Fig. 7 and which incorporates an arrangement of eccentric weight mechanism somewhat different from that shown in Figs. 4 and 5.

Figure 7 is a side elevation, with certain parts shown in section, of a modified construction of barking machine.

Figures 8 and 9 are plan and elevation views of a portion of the construction shown in Fig. 6 and drawn to a larger scale.

As will be seen from Figure 1 the bark-removing member, which consists of a scraping memher, is provided with an edge portion i turned towards the log and serving for the removal of the bark. Counting in the direction of operation the fore part of said edge portion is provided with a sliding surface 2, which-counting also in the direction of operation of the scraping memberinclines backwards or presents a substantially radial inclination relatively to the scraping edge portion 1 for the purpose of making it easier for the scraping member to slide out of hollows. in the log and torpass bulges thereon. The sliding surface of the scraping member can be shaped as for example in Fig. 2 wherein it will be seen that the surface 2 tapers from each side toward the center, or it can be shaped as shown at 2 in Fig. 3 where it will be seen that it tapers from one side toward the other side, said other side being straight. The scraping member is caused to rotate around the log 3 in the direction of the arrow, the bark being then peeled off. When a new log is to be introduced the scraping mem-- her, as a rule, has left the barked log and, by a centrifugal weight 6 as shown in Figs. 4 and 5, been returned to its inoperative position (shown in dashed lines in Figure 1). Due to the direc tion of rotation of the scraping member and due to the fact that said member does not extend past the center of the log, counting from the point where the scraping member is articulated to a pivot ll, said pivot extending substantially parallel with the longitudinal direction of, the log and being mounted on a rotatable supporting member 4a which rotates around the log, the frictional forces tend to move the edge portion I of the scraping member onto the circumference of the log. In order to facilitate the insertion of the log between the scraping members thespeed of rotation of the drum may be reduced, the centrifugal weight 5 and with it also the scraping member being then actuated by asmaller centriiugal force, which-due to the connection of the centrifugal weight with the scraping memher-aims at moving the latter towards the center of the drum. It is also possible to reduce the speed to such an extent and to adjust a spring, 5, which serves as a regulating means, in such a way that the latter will be able to press the centrifugal weight 6 (while overcoming the centrifugal iorce acting thereon) and with it also a spindle 1 inwards towards the center'of the drum,'the scraping member then moving outwards. 0n

the spindle 1 there is provided a lug 8, which actuates an extended portion 9 of the scraping member and which, of course, will then also move inwards. The scraping edge portion l of the scraping member can swing outwardly around pivot 4 until the member abuts an adjustable set screw ID, or it can swing inwardly until lug 8 abuts a ring I I.

By reducing the number of revolutions of the drum in such a manner that the inwardly directed force of the spring 5 will overcome the outwardly directed force of the weight 6 the edge portion i of the scraping member will be moved outwards thus making it possible to introduce the log without the latter striking the scraping member (members). When the end of the log has reached a position immediately inside the scraping members, feeding of the log is stopped and the speed of the drum is increased, so that the counter-poise weight 6 is moved outwards by centrifugal force and actuates a spring l2 by means of the spindle 1, the spring [2, in its turn, actuating the extended portion 9 of the scraping member and the scraping member 2 being brought into contact with the log, after which the feeding of the log is resumed. The spring I2 provides for an elastic connection between the counter-poise weight and the scraping member, enabling the latter easily to follow the irregularities of the log.

Between an outer end Wall of the weight 6 and the confronting end wall of the casing or cylinder 13 an additional spring l4 may be provided for the purpose of reducing the eifective centrifugal force of the counter-poise weight 6, such eral speed of the scraping member and the sur- ,7

face of the log is greater than for smaller diameter logs, assuming a constant number of revolutions per minutes of the drum.

In the foregoing a description has been made of the way in which the scraping members may I be brought into an open position, which may be applied when introducing logs which because of their shape or due to other circumstances may be difiicult to introduce between the scraping members. however, take place, the scraping members themselves automatically making their way on to the circumference of the log due to circumstances already mentioned. In such an operation, the logs can be fed axially one after another in abutting relation, so that no remaining bark will be left at the ends of the logs.

The most important details of the machine having now been described, Figs. 6-9 show how a machine according to the invention may be arranged. Only one scraping member I, 2 and associated counterpoise weight system is shown in the embodiment of Figs. 1-5 but it is preferable to provide several such scrapers and counterpoise systems each being evenly spaced from the other in the peripheral direction with a view to obtaining, on one hand, a better barking effect and, on the other hand, an evenly distributed pressure around the whole circumference of the log, thereby causing the scraper Normally, this operation need not,

members to tend, to some extent, to keep the log centralized.

The several scraper members and counterpoise systems can be of the construction shown in Figs. 1-5 wherein the counterpoise weight slides rectilinearly in a cylinder. However the same result can be obtained with a somewhat different arrangement of the counterpoise weight which will be hereinafter described.

The construction according to Figs. 6-9 comprises a drum 26 rotatably mounted on, for example, eight rollers 29, which maintain the drum properly aligned in both a radial and axial direction. A grooved pulley 30 which is integral with the drum is provided to enable the drum to be rotated by a belt drive (not shown). The several scraper members 31, there being four in the illustrated embodiment, are mounted pivotally on pins 38 which extend through the end 21 of the drum, and above the scraping members 31 there is a protecting member 3| tightening against the drum. Preferably, the log is fed into the machine from the left by means of spiked or toothed rollers 32 and, the log having passed said rollers, it is pulled out of the machine by similar spiked or toothed rollers 33. The rollers are arranged in such a manner that they will always keep the log at the center of the drum, i. e. that if the lower roller moves in one direction (upwards or downwards) the upper roller will move in the opposite direction.

In Figure '7 one log 3 is shown, and, as will be seen from the figure, only the periphery of the log wil1in view of the shape of the scraping members in this case-be brought into contact with the scraping members. The scraping members will then get a good hold on the log and will easily move onto the circumference of the log. By giving that portion of the scraping members which faces the log the shape of a sharp edge such hold will be further improved. Due to the shape shown in Figure 7 the scraping members will also move the log towards the center of the drum.

As shown in Fig. 6 and in the enlarged fragmentary detailed views of Figs. 8 and 9, each scraper member 37 is articulated to the pivot pin 38 and is connected to a counterpoise weight M] by a spring 39 so as to be elastically actuated by the counterpoise weight 40. The counter-poise weight 40 is adjustable on an arm 4|, which is rigid with an arm 43, to which the spring 39 is fixed. The arms 4!, 43 are adapted to turn on a pin 42. A spring 44 has the same function as the spring l4 and/or 5 in the embodiment of Fig. 4. The system is meant to rotate in the direction of the arrow.

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

1. An improved barking machine of the kind having a supporting member rotatable around a log to be debarked, said machine comprising at least one bark-removing member mounted on said supporting member and movable into and out of engagement with the log, a weight or similar member mounted on the rotatable supporting member for actuating the bark-removing member and movable outwardly by centrifugal force upon rotation of said supporting member, and means elastically connecting the weight to the bark-removing member whereby upon outward movement of the weight, said means effects elastic pressure of the bark-removing member on the log so that the bark-removing member will move easily along irregularities of the log.

2. An improved barking machine as claimed in claim 1, the bark-removing member being swingable on a pivot, and said means elastically connecting the weight to the bark-removing member comprising a spring.

3. An improved barking machine as claimed in claim 2, the bark-removing member being provided with a bark-removing arm on one side of the pivot and with an angularly protruding arm, which is located on the other side of the pivot and which is under the influence of the spring, said spring being provided on a spindle connected to the Weight member and moving with the latter.

4. An improved barking machine as claimed in claim 2, the weight member being connected to a swingable arm, which in turn is connected to the spring.

5. An improved barking machine as claimed in claim 1, the weight member cooperating with regulating means providing a regulating force acting preferably in a direction contrary to that of centrifugal force, whereby the elastic log contact pressure varies with diiferent log diameters, preferably in such a manner that the elastic pressure of the bark-removing member on the log will increase automatically with increasing log diameter.

6. An improved barking machine as claimed in claim 5, in which the weight member is connected to the bark-removing member in such a way that when the weight member is being moved outwards and inwards, respectively, the bark removing member will tend to move inwards and outwards, respectively, the regulating means cooperating with said weight member in such a manner that on a decrease of the speed of rotation of the weight supporting member said regulating means is able to press the weight member inwards, thus overcoming the centrifugal force, and thereby causing an outwardly directed movement of the bark-removing member for the purpose of facilitating the introduction of a new log.

7. An improved barking machine as claimed in claim 6, said regulating means being constituted by a spring, and there being provided an additional regulating member in the form of a spring cooperating with the weight member to counteract the outwardly directed force of said weight member the more the latter is moving outwards under the influence of centrifugal force.

References Cited in the file of this patent UNITED STATES PATENTS