POLE OR SIMILAR

The subject invention is directed to a method of making holes in a log, wooden pole, or the like for sub¬ sequent impregnation thereof, comprising the steps of introducing the log, pole, or the like into a punching machine, securing the log, pole, or the like in the machine, causing a plurality of punching units to force their perforating elements into the log, pole, or the like within a first peripheral area thereof, pulling out the perforating elements from the log, pole, or the like, releasing the log, pole, or the like in the machine, turning the log over a predetermined angle and resecuring it, forcing the perforating elements into the log, pole, or the like within a second peripheral area of the log, repeating the punching cycle until the entire circumfe- rence of the log or the like is perforated, at least over a part of its length, and removing the log or the like from the punching machine.

The invention is also directed to a machine for punching holes in a log, wooden pole or the like for sub- sequent impregnation thereof, comprising transfer means designed to introduce the log or the like into the machine and to remove it therefrom, a foundation, and a frame cooperating therewith, at least two driven roller units which are rotatably mounted on the foundation, holding-on arms cooperating with the corresponding roller units and movably supported by the frame to temporarily secure the log, or the like in the machine, and a plura¬ lity of punching units each including a perforating ele¬ ment, each element being displaceable in the longitudinal direction of its associated punching unit.

More precisely the invention concerns preparation of wooden poles, logs, trunks, stocks or the like for impregnation by means of a fluid to protect the wood

against rot, insects and like and/or to render the wood flame retardant.

It is generally known to achieve such impregnation by dipping the wood into a tank filled with the impreg- nating liquid, by brushing the wood surface with the fluid, by spraying the wood or by treating it in an auto¬ clave partly filled with impregnating fluid in a cycle comprising various pressure and heat conditions. With the latter, often preferred impregnation method impregnation to deep levels cannot, however, be achieved. For this purpose, it is known to perforate the wood surface with the aid of needles, drills or chisels. In practice, pene¬ tration depths up to 10 mm may be obtained, however often resulting in the fibres being damaged during the punching operation with consequential reduction of strength. It is not either unusual that the perforating elements (pins, needles etc. ) break as they hit a knot or other kind of heavy resistance.

In order to obtain wooden power distributing poles having a reasonable length of life it is therefore neces¬ sary to impregnate the wooden poles with a pesticide, usually creosote or a metal salt, to a deep level, espe¬ cially in the critical lower part of the erected pole around an annular zone at ground level. US-4,596,717 discloses a method of perforating a wooden plank for subsequent impregnation. A plurality of needles are being forced at the same time and by mecha¬ nical means into the plank while the latter is being dis¬ placed. There is no individual adjustment of the penetra- tion depth of the needles and only one side, viz. the upper side, of the rectangular wooden plank is perfo¬ rated.

DE-19 36 270 illustrates a method and a machine for punching a log in accordance with the preambles of claims 1 and 5. This publication does not either disclose indi¬ vidual application and adjustment of the various piercing means, the construction and function of which are quite

different from those of the inventive object. In addi¬ tion, this prior-art machine lacks the features of auto¬ mation and flexibility that characterise the subject invention. The purpose of the subject invention is to provide a method and a machine making it possible to obtain a guaranteed quality of logs, wooden poles and the like for particular applications while at the same time reducing the use of pesticides, insecticides and the like. A further purpose of the invention is to provide an automatic and adjustable punching sequence in a log, pole and the like, including individual adjustment of the penetration depth of the various perforating ele¬ ments around the log periphery and along a limited length of the log.

Yet a further purpose is to provide punching of a wooden pole or the like to a considerable penetration depth and with a minimum of wood destruction, and with a punching hole array that could easily be adapted to the prevailing need.

These purposes are achieved in accordance with the invention by means of a method of the kind outlined above, which is characterised by the steps of sensing the diameter of the log, wooden pole or the like, and storing the measurement data in a computer designed to calculate the punching sequence, by a plurality of first piston means causing their associated punching units to abut against said log while exerting a certain pressure there¬ on, by individually controlling the penetration of the perforating elements by means of the computer, and by determining, by means of the computer, the turning angle of the log or the like at each step of the punching cycle.

A machine for performing said method and possessing the features indicated above is characterised by a sens¬ ing bar designed to measure the diameter of the log, or the like and including a transducer for emission of a

corresponding signal to a computer, a plurality of first piston means, each displaceably supporting its associated punching unit, each first piston means comprising a first displaceable cylinder housing and a piston rod, which is secured to the foundation, and each punching unit com¬ prising a second cylinder housing, which is formed inte¬ grally with the first cylinder housing, and a piston rod supporting the perforating element at its end, said ele¬ ment arranged to be extended to project past the free end of the second cylinder housing by way of a guide in said cylinder end, and in that the machine further comprises advancement rollers supported by the frame to be displac¬ ed oppositely and towards/away from the punching units, a power plant to actuate the advancement rollers and/or the roller units in order to turn the log or the like over a predetermined angle, and a computer unit to individually control the operations of all piston means, the actua¬ tion of the roller units, the holding-on arms, and the advancement rollers for the purpose of controlling the punching sequence.

Further developments of the invention will appear from the characteristic features defined in the dependent claims.

A preferred embodiment of the invention will be described in the following as an example with reference to the accompanying drawings, in which:

Fig. 1 is a view from above, schematically illu¬ strating a punching machine for making holes in a wooden pole in accordance with the invention, the machine compo- nents positioned above the pole having been excluded for the sake of clarity;

Fig. 2 is a sectional view through the machine in accordance with Fig. 1 along line A-A, schematically illustrating the main components of the machine; Fig. 3 is a partial sectional longitudinal view through a punching means, the piston means displaceably

supporting the latter, and its associated perforating element; and

Fig. 4 is a flow chart of the machine operations. The subject invention allows punching of a wooden pole, log or the like for subsequent impregnation, and particularly punching using a method know as incising. Incising is a method of making holes having a depth of approximately 50 mm in a predetermined area having a length of 1.8 m in the lengthwise axis of the power dis- tributing pole. The punching array and position appear from Fig. 1. The method in accordance with the invention makes it possible to impregnate the root area to an extreme extent, rendering the lower critical part of the pole situated at ground level more rot-resistant. Techni- cally, the method involves dense piercing, carried out by means of individually hydraulically operated needles, the pole blank thus being prepared to allow the impregnating medium to penetrate deep into the wood in the root area. In the upper part of the wooden pole considerably smaller amounts of creosote are needed than may be achieved using today's impregnation methods. Owing to the technology suggested herein, the amounts of pesticides may be reduc¬ ed by 25% while at the same time the average life of the wooden pole is lengthened. Referring initially to Figs 1 and 2, the punching machine comprises a foundation or base 1 and a frame 2 cooperating with the foundation. The log, wooden pole or the like 3 to be pre-treated by means of punching (incis¬ ing) is supported on a number of roller units 4 two of which preferably are rotatably mounted on the foundation 1. Holding-on arms 33 are movably supported by the frame 2 and cooperate with the above-mentioned rotatable roller units 4 to temporarily secure the log 3 in the machine during the punching cycle. In addition, the machine com- prises a plurality of punching units 5 including perfo¬ rating elements 6 and each punching unit 5 as well as its associated perforating element 6 are arranged to be dis-

placeable in the longitudinal direction of the punching unit, essentially towards the centre of the log. In the practical performance of the invention, 33 duplex pistons are used together with the roller units mentioned above, spaced approximately 3 meters apart and using nails as the perforating elements, as will be explained in closer detail in the following. Opposite the punching units 5, on the other side of the log 3, a pair of advancement rollers 7 are mounted in the frame 2 to be displaced in a direction towards and away from the punching units. A sensor arm 8 which is associated with the advancement rollers 7 so as to be displaced together therewith mea¬ sures the diameter of the log 3 jointly with capacitive transducers 9, in response to which a corresponding sig- nal is emitted to a computer (not illustrated), as will also be explained in closer detail in the following. A transfer means 10, schematically illustrated in Fig. 2, is arranged to introduce the log into the machine, posi¬ tioning it above the punching means 5, and conveyance rollers 11 are provided to move the treated log out of the machine, following the conveyance rollers 11 having lifted the log 3 away from the roller units 4. Fig. 1 schematically illustrates the incising (punching) array 12 which in the case of a power distribution pole is positioned at one end of the pole, the so-called root end. In addition, numeral reference 13 indicates a hydraulic pump serving associated components in the machine, and numeral reference 14 indicates the machine control system. Reference is now made to Fig. 3 which in a partial sectional view illustrates the construction of a punching unit 5 and its associated components in detail. A first piston-and-cylinder unit (back-up cylinder) 15 displace¬ ably connects the punching unit with the stand 1. The piston rod 16 of said cylinder unit preferably is detach- ably secured to the stand, e.g. by means of a screw joint. A piston 17 is secured at the free of the piston

rod so as to move inside a cylinder housing 18. Ports 19 and 20 are connected to their respective one of the cylinder housing end walls to ensure supply of a pressur¬ ised fluid, preferably hydraulic oil, to effect displace- ment of the cylinder housing 18 from (via port 20) and towards (via port 19) the foundation. Each punching unit 5 comprises a second piston-and-cylinder unit (incising cylinder) 21 including a cylinder housing 22, formed integrally with the first cylinder housing 18, and in which a piston 23 is arranged for movement. A piston rod 24 extends from the piston 23 so as to project from the cylinder housing 22 and into a punching a nozzle 25. The free end of the piston rod 24 supports a perforating ele¬ ment 6 the pointed end of which is mounted in a guide 26 formed in the end wall 27 of the punching nozzle 25. The perforating element 6 is needle-shaped and preferably consists of an incising nail. In accordance with the illustrated embodiment, a nail is removably attached to the end face of the piston rod 24 by means of an aper- tured cap member 28 having internal threads therein in screw engagement 29 with corresponding threads formed on the jacket face of the piston rod. The perforating ele¬ ment 6 is caused to project outwards through the end wall 27 when actuated by a pressurised fluid, preferably hydraulic oil, which is supplied into the cylinder hous¬ ing 22 via a port 30, and to retract when actuated by a pressurised fluid which is supplied into the cylinder housing via a port 31 (the cylinder housing being drained via the port 30) . Referring again to Fig. 1, and particularly to

Fig. 2, the punching method in accordance with the inven¬ tion will be described in the following. A pole blank 3 is advanced from a previous pre-treatment station or storage along a conveyance line 32 up to the punching machine and is introduced into the machine with the aid of the transfer means 10. The pole is supported on the roller units 4 (conveyance rollers 11 have been lowered

to a level below the latter) and by means of the above- mentioned holding-on arms 33 it is clamped against those rollers that are arranged within the machine. The ad¬ vancement rollers 7 are moved into abutment against the pole, whereupon the sensor arm 8 supplies a computer, not illustrated but preferably being a so-called PLC compu¬ ter, with information on the diameter size of the part of the log to be perforated. Supplementary information and data regarding the manner of performing the perforations on the log, i.e. perforation density, penetration depth of each individual perforating element, perforation array etc. , are stored in the computer. The computer activates the control system 14 which in turn controls the hydrau¬ lic circuit and the drive motors (not illustrated) actuating the rolling equipment. In consequence, pres¬ surised fluid is supplied to the ports 20 of the first cylinder units 15 so as to displace each punching unit 5 into abutment with the pole 3 while exerting a predeter¬ mined pressure thereon. Thereafter the extension of the perforating elements 6 is controlled individually by supply of pressurised fluid to the corresponding ports 30 of the second cylinder units 21, whereby the perforating elements 6 will be pushed into the pole 3, perforating the latter in accordance with a predetermined array. During this operation, the advancement rollers 7 serve as back-up means. When the punching cycle is completed, pressurised fluid is supplied to the ports 31 and 19 of the cylinder units, and drainage is effected via ports 20 and 30. When the punching units 5 and the first cylinder units 15 have returned to the original position, the holding-on arms 33 are raised and the pole 3 is turned over an angle determined by the computer, with the aid of the motor-operated advancement rollers 7 and, as the case may be, also by motor-operated roller units 4. The punch- ing cycle as defined above is then repeated the number of times required to perforate the entire pole circumference within a selected area in the lengthwise direction there-

of. When power distributing poles are incised this zone is positioned at one end of the pole as indicated in Fig. 1. If a denser perforation pattern is desired, per¬ foration overlap may be produced by turning the pole over a smaller angle.

When the perforation operation is completed and when the holding-on arms and the advancement rollers have been moved out of engagement with the pole 3, the conveyance rollers 11 are raised, lifting the pole away from the roller units 4 to be conveyed from the machine and up to a subsequent impregnation station or so-called sorting pocket. The pole conveyance and punching operations thus are completely automated.

Finally, reference is made to Fig. 4 illustrating an example of a flow chart of a punching cycle. With the aid of pressure guards the penetration into the pole of pre¬ ferably each perforating element could be surveyed and controlled.

The invention is not limited to the features de- scribed above and illustrated in the drawings but could be varied within the scope of the appended claims.