US 3196912 A
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BRUNDELL HANISMS FOR T DEBARKING ETAL 3,196,912
HE TOOLS IN A LOG MACHINE 3 Sheets-Sheet 1 July 27, 1965 P. G. CONTROLLING MEG Filed April 25, 1962 y 27, 1965 P. a. BRUNDELL ETAL CONTROLLING MECHANISMS FOR THE TOOLS IN A LOG DEBARKING MACHINE Filed April 23, 19 62 3 Sheets-Sheet 2 July 27, 1965 P. 5. BRUNDELL ETAL 3, 2
CONTROLLING MECHANISMS FOR THE TOOLS IN ALOG DEBARKING momma Filed April 2:5, 1962 s Sheets-Sheet :s
United States Patent 3,196,912 CUNTRQLLING MECHANEMS FGR THE TGULS IN A lLQG DEBARKHNG MACHINE Per Gunner Brundell, Tolfiors, Ga le, and Karl-Erik Arnold .l'onsson, Gayle, Sweden, assignors to Soderharnns gerlstader Ali, Soderhamn, Sweden, a corporation of we en rues Apr. 23, 1962, her. No. 189,467 Claims priority, application fivveden, May It), H61, 4,?41/ 61 3 Claims. (Cl. 144-208) The invention relates to a debarking machine of the type in which an annular rotor journalled in a stator has a central opening through which logs are to be passed. The rotor carriers bark-removing tools mounted to swing towards and away from the center of the opening in a plane substantially normal to the axis of the rotor, and resilient means are provided to cause the tools to swing inwardly to engage resiliently the surface of a log fed through the rotor.
In the operation of such a machine it may sometimes, for some reason or other, be desired that the advance of a log introduced in the rotor is temporarily stopped, e.g. for cutting off the log. If, during such stoppage, the machine is allowed to continue its operation there will be a risk that the tools cut or turn a more or less deep annular groove in the surface of the log.
The object of the invention is to obviate this drawback and for that purpose the invention provides a device by means of which the tools can be retained in inoperative position during the rotation of the rotor. Thus, the rotor has mounted thereon retaining means adapted, when operated, to prevent each tool from moving in wards from a position reached, and a stationary release member is then adapted to be actuated manually to put all of said retaining means into operation at any moment during a debarking operation. In this way, the tools will be retained on a circle having its center in the axis of the rotor and circumscribing the outermost point of a log surface contacted by the tools. It may be noted that said retaining means are not adapted to displace the tools radially outwards against the action of rather heavy resilient means but only serve to prevent the tools from a further inward movement which might cause a continued peeling of the log surface.
In a suitable embodiment, each retainin mean consists of a fluid pressure operated cylinder provided with a piston rod and connected to a pressure fluid accumulator by means of a conduit containing a normally closed solenoid valve which is adapted to be opened on actuation of a stationary switch inserted in the circuit of said solenoid. The opening of the valve causes the piston rod to move outwards, and thus either said rod or the cylinder may serve as a retaining member, Another mechanism is then provided to automatically prevent the return of said member from its retaining position. The locking mechanism may consist of a catch operated by means of an electromagnet in some known way, but in a preferred embodiment said conduit between the accumulator and the cylinder may also contain a non-return valve closing onto the accumulator and thus preventing the baclzflow of the pressure fluid' when the retaining member is subjected to the pressure of the tool spring. To permit the return of the pressure fluid to the accumulator and thereby the release of the retaining member it is, however, necessary in this case to provide a second conduit containing a normally open solenoid valve which is adapted to be closed when the solenoid valve in the first conduit i opened.
The invention will be described more in detail with reference to the accompanying drawing which show two different embodiments.
In the drawings,
FIGURE 1 shows the location of retaining mechanisms on the rear side of the fore end Wall of a debarking rotor in which belts or bands of rubber are provided to swing the tools.
FIGURE 2 shows a more detailed view of a portion of the same wall and one of the retaining mechanism on a larger scale.
FIGURES 3 and 3a show another embodiment applied on a debarking tool actuated by other resilient means.
FIGURE 4 is a cross-sectional view illustrating the stator and rotor relationship.
The rotor shown in FIGS. 1 and 2 may be of the type described in the US. Patent No. 2,857,945. Three debarking tools 3 are provided before the fore end walls of the rotor equally spaced around the periphery. The tools 3 are secured to pivots 4 journalled in said wall 5. On the rear side of the wall 5 (shown in FIGS. 1 and 2) each pivot 4 has secured thereto a crank carrying a pin 7 directed axially rearwards. Each pin '7 is by means of one or more elastic belts or hands 8 of rubber coupled to a pin 9 inserted in the wall 5 at a distance from the pivot 4 of the pertaining crank. As apparent, the arrangement is such that the rubber bands strive to swing the tools 3 inwards towards the axis of the rotor. Shortly before the free ends of the tools meet at said axis or center line, however, the inward swinging movements are stopped by stationary abutments. For that purpose, fins 10 projecting axially from the cranks 6 are arranged to abut rubber pads 11 carried by angle irons 11a which are secured to the wall 5 inside the rubber belts 8. The construction described hitherto is known previously.
According to the invention, one retaining mechanism is provided for each of the debarking tools 3 and therefore only one of these mechanisms Will be described below with reference to FIG. 2. A hydraulic cylinder 12 having a piston rod 13 is secured to the rotor wall 5. The piston rod and adjacent end of the cylinder extend through a transverse opening in the limit stop 11, 11a in such a way that the piston rod 13 in its fully retracted position has it end located in the same plane as the stop surface of the pad 11 that faces the tin it The rear end of the cylinder 12 is by means of two conduits i4, 15 connected to the fluid chamber of a pressure fluid accumulator 16. According to a known construction, the accumulator also includes a chamber separated from the fluid chamber by a flexible diaphragm and filled with gas under pressure whereby a required pressure in the closed system can be maintained. The conduit 14 contains two valves: a nonreturn valve 1'7 opening towards the accumulator and a solenoid valve lit which is open when the circuit through the solenoid is open. Also the conduit 15 contains two valves: a non-return Valve 19 opening towards the cylinder l2 and a solenoid valve 2! which is closed when the circuit through the solenoid is open. In other words, in the illustrated arrangement fluid can flow from accumulator re past valve 29 when it is open through conduit 15 and past check or non-return valve 15", in the direction of arrow X, toward cylinder 12 but cannot flow back past the valve 719. On the other hand, fluid can fiow from cylinder 12 through conduit 14 past non-return valve 37, in the direction of arrow Y, and past 13 when it is open to accumulator 16 but it cannot flow in the reverse direction past valve 17 toward the cylinder 12.
A cylindrical rotor wall 21 indicated diagrammatically in FIG. 2 and extending along the outer periphery of the end wall 5 carries on its exterior surface two peripheral rails 22 and 23, one of which 23 is electrically insulated. Brushes 24 and 25, respectively, are mounted on a stator 35a, in contact with said rails 22, 23. Bearings 36 journal the rotor relative to the stator, see FIG. 4-. The brush 24 is connected to ground by means of a conductor 26, and the brush 25 is connected to a source of current by means of a conductor 27 containing a normally open switch 23. The solenoids of the valves lid, 20 are by means of conductors 29, 3t 31 connected in series between the two current carrying rails 22, 23.
It may be assumed that in an initial position, not shown, the tools 3 engage the surface of a log (32 in FIG. 1), the advance of which through the rotor it stopped, To prevent a continued peeling of the annular log section opposite to the tools, the switch 28 is now actuated so that the solenoid valve 18 in the conduit 14 is closed and the solenoid valve Zti in the conduit is opened, and thereby pressure fluid is supplied to the cylinder 12 through the non-return valve 19. This causes the piston rod 13 to move outwardly to hit the fin it} of the crank 6 irrespective of the actual position of the tool 3. The pressure in the cylinder 12 is quite insufficient to cause any displacement of the tool outwards from the log surface against the action of the strong rubber spring 8, but on the other hand the tool has no possibility to swing in opposite direction, is. inwards, as the non-return valve 19 closes the conduit 15, as soon as the piston rod is actuated by the spring 8 and thereby causes a higher pressure in the cylinder 12 than in the accumulator 16. As long as the switch 28 is closed and the valve is open, the piston rod 13 follows the arm 6, if the log, which often i not quite round, should cause some further outward movement of the tool. As already mentioned, all retaining or blocking mechanisi is that is, position limiting means, are of the same design, and they are all connected to the current rails in the same way to be put into operation simultaneously on actuation of the switch 28.
In FIG. 1, it has been assumed that the rotor has rotated about half a turn after the retaining mechanisms have been put into operation. One of the tools, designated by A, has just reached the log surface portion 33 located at the greatest distance from the center of rotation. The tool B before the tool A has been blocked or limited in the position reached when passing the surface portion 33, whereas the tool C behind the tool A is still in engagement with a successively rising log surface. After a rotation of at most one turn all tools have been positioned with their edges disposed on a circle 34 having its center on the axis of the rotor and circumscribing the most protruding surface portion 33, whereby a continued debarking is excluded.
When the interrupted advance of the log is again to be resumed, and the debarking is thus to be continued, the switch 28 is returned to its normal open position, whereby the solenoid valve 20 is closed and the solenoid valve 18 is instead opened. Now, the piston rod 13 is forced back by the spring 8, as the liquid has free passage to the accumulator 16 through the conduit 14. The non-return valve 1'7 prevents a flow in opposite direction, when the action of the spring against the piston rod 13 is temporarily relieved.
In the embodiment in FIG. 3, the crank 35 on the pivot 4- of the tool 3 is hinged to the piston rod 36 of a piston 37 in a cylinder 33. A cylinder space behind the piston 37 is by means of a conduit 39 connected to another cylinder lt) containing a piston 41. The space formed between the two pistons 37 and 41 is filled with liquid actuated by the pressure of a heavy helical spring 42 mounted on the rear side of the piston 41. The conduit 39 contains a normally open solenoid valve 4-3 adapted to be controlled by a stationary switch 28 arranged in a circuit including the components similar to those illustrated with respect to the form shown in PEG. 2. A branch conduit 44 connected to the conduit 39 on both sides of the valve 43 contains a non-return valve 45 opening toward the cylinder 40. When the valve 4-3 is open, the two cylinders 38 and will evidently serve the same purpose as the rubber spring 8, i.e. to move the tool resiliently onto the log. ()n the other hand, when the vazve 43 is closed, the device will function as a retaining mechanism in the same Way as the embodiment first described, in that the non-return valve 45 retains the tool 3 on the circle circumscribing the outermost portion of the log.
FIG. 3a shows a modified embodiment, in that the piston 41 and the spring 42 are replaced by an elastic bladder 46 connected to a source of compressed air, not shown.
In both the embodiments described, the electrical control circuit may very well be replaced by control means operating mechanically, hydraulically or pneumatically.
What we claim is:
l. A debarking machine of the hollow-head type includin a stator, a rotor journalled in the stator having a central opening through which logs to be debarked are passed, a plurality of shafts journalled axially in said rotor, a bark-removing tool carried by the rotor and mounted for movement toward and away from the axis of the opening, a crank fixed to each shaft, fixed members on the rotor respectively spaced from each crank in the direction of movement thereof, resilient means con nected between each crank and associated fixed member to cause the associated tool to swing inwardly to resiliently engage the surface of a log fed through the rotor, hydraulic pressure operated cylinders mounted on the rotor and a movable piston in each cylinder adapted, when moved, to engage one crank in opposition to the action of said resilient means, a hydraulic pressure accumulator, a supply conduit from the accumulator to the cylinder including a normally-closed solenoid operated valve and a non-return valve opening towards the cylinder, a return conduit from the cylinder to the accumulator including a normally-open solenoid operated valve and a non-return valve opening towards the accumulator and a stationary switch connected in the circuit with the solenoids and adapted, when operated, to reverse said solenoid valves, whereby the pistons of the cylinders are operated to serve as blocking members.
2. A dcbarking machine of the hollow-head type including a stator, a rotor journalled in the stator having a central opening through which logs to be debarked are passed, a plurality of shafts journalled axially in said rotor, a bark-removing tool carried by each shaft and mounted for movement toward and away from the axis of the opening, a crank fixed to each shaft, means connected with each crank to cause the tools to swing inwardly to engage the surface of a log fed through the rotor to debark the same, hydraulic pressure operated cylinders mounted on the rotor and a movable piston in each cylinder for engaging one crank in opposition to the action of said means, a hydraulic pressure accumulator, a supply conduit from the accumulator to the cylinder including a normally-closed solenoid operated valve and a non-return valve opening towards the cylinder, a return conduit from the cylinder to the accumulator including a normally-open solenoid operated valve and a nonreturn valve opening towards the accumulator and a stationary switch connected in the circuit with the solenoids and adapted, when operated, to reverse said solenoid valves, whereby the pistons of the cylinders are operated to serve as blocking members.
3. A debarking machine comprising a stator, an annular rotor journalled in the stator and having a central opening through which logs are to be passed, a plurality of shafts journalled axially in the rotor, equally spaced around said central opening and each carrying a barkremoving tool adapted for swinging movement towards and away from the center of the opening in a plane substantially normal to the axis of the rotor, a crank fixed to each shaft, a hydraulic cylinder and piston unit for each crank, each piston having a rod connected to the associ ated crank, 21 second hydraulic vessel, conduit means connecting the cylinder space remote from the piston rod to said second vessel, means generating a hydraulic pres- E5 sure in said second vessel, a normally open solenoid valve in said conduit means, a by-pass conduit connected to said first conduit means on opposite sides of said valve, a non-return valve in one portion of said by-pass conduit opening towards said second vessel, and a manually operated stationary switch connected to close all solenoid valves upon manual operation so as to position the tools with their tips held lying on the circumference of a circle having its center at the axis of the rotor and circumscribing the outermost point of a log surface contacted by the tools.
References Cited by the Examiner UNITED STATES PATENTS 2,798,519 7/57 Hansel 144208.5 5 2,802,495 8/57 Nicholson 144208.5 2,925,107 2/60 Fitzwater 144208.5 3,053,294 9/62 Andersson 144-208.5
LESTER M. SWINGLE, Primary Examiner.
10 EARL EMSHWILLER, WILLIAM W. DYER, 111.,