WO1980002709A1

WO1980002709A1 - Wooden pole for power lines or the like,and machine for producing same

Info

Publication number: WO1980002709A1
Application number: PCT/NO1980/000020
Authority: WO
Inventors: H Berge; L Stokkeland
Original assignee: H Berge; L Stokkeland
Priority date: 1979-05-31
Filing date: 1980-05-30
Publication date: 1980-12-11
Also published as: DK160715C; ES8104736A1; DK160715B; GB2064618A; FI801707A; SE8100526L; AT380717B; NO150525C; ATA904780A; NO150525B; EP0029831A1; AU5986580A; ES492047A0; DE3047565A1; GB2064618B; EP0029831B1; CA1144734A; SE443014B; DK26281A; NO791814L

Abstract

A wooden pole or standard for power lines or the like comprises a number of staves (2) having trapezoidal cross-section with side faces forming a mutual angle of 360/n degrees, n being the number of staves in the pole, and which staves are glued together along adjacent side faces so that a pole (1) having a centrally extending hollow space is formed. All staves (2) are equally shaped lamellae in a number which, for the cross-sectional dimension in question, is sufficiently large to achieve a laminated structure in the circumferential direction of the pole, and the individual lamellae are, as required, finger jointed for achieving the desired pole length. A machine for manufacturing staves for such a wooden pole comprises a milling device consisting of a pair of milling spindle holders (14a, 15a) arranged on respective sides of a feeding means (17) for stave blanks (11), and which are angularly adjustable and have milling tools (12, 13) for shaping of opposite side faces of the stave blanks. One of the spindle holders (15a) may, during feeding of a stave blank (11), be moved outwards and away from the other spindle holder (14a) with a speed which is related to the feeding speed of the stave blanks (11). The movement of the spindle holder (15a) is started and stopped automatically by means which are actuated by the forward and rearward end, respectively, of a stave blank (11), and the spindle holder (15a) is returned automatically to the initial position by stop of said movement.

Description

Wooden pole for power lines or the like, and machine for producing same

The present invention relates to a wooden pole or standard, especially for line carrying in connection with power lines or the like, and comprising a plurality of elongated staves having trapezoidal cross-section with parallel inner and outer surfaces and side faces forming a mutual angle of 360/n degrees, n being the number of staves in the pole, the staves being glued together along adjacent side faces to form a pole with a centrally extending hollow space. In the construction of power lines, telephone lines and the like, by which there are used poles or standards of ^"wood, there have hitherto predominantly been _.used poles or standards of solid wood of high quality, more specifically logs or boles which are as straight and clear-boled as possible. As known, however, it is often difficult to procure wooden poles satisfying the demands made with respect to straightness and clear-boledness, particularly when it is the question of larger mast-trees.

From British patent specification No. 745 540 there is known a hollow, tapering lamp standard consisting of stave elements glued together and having trapezoidal cross-section such as stated above. More specifically, the known standard or pole consists of four main side elements and four rela¬ tively narrow corner elements, the side elements being tapering from the bottom to the top whereas the four corner elements have constant width along the hole length, and in addition loose fillets are inserted in grooves in the adjacent element surfaces to reinforce the structure. Thus, the known standard consists of differently shaped elements and is not so rational to manufacture as is desirable and necessary in connection with e.g. power line masts. Further,

O PI it has not the same strength and rigidity in all directions, and especially by larger standards of this type there will easily occur cracks, especially in the wide side faces, which cracks are weakening and detrimental. The object of the present invention is to remedy th above-mentioned lack of suitable poles of wood, and to provide a pole or standard which may be manufactured rationally and economically and with a minimum of material consumption yields the desired rigidity and strength in all directions, at the same time as the pole may be manufactured with the lengths and diameters and with the conicity which might be needed in each different case.

The above-mentioned object is achieved with a woode pole or standard of the type set forth above, and which is characterized in that all of said staves are equally shaped lamellae in a number which, for the cross-sectional dimensio of the pole in question, is sufficiently large to achieve a laminated structure in the circumferential direction of the pole, and that the individual lamellae as required are finge jointed for achieving the desired pole length.

By means of the laminated, axis-symmetrical pole or mast structure according to the invention there is achieved maximum strength and bending resistance in relation to the cross-section of the used materials, and the same strength and bending resistance in all directions. This is of impor¬ tance by erection, as one does not have to orient the standard or mast in a definite direction. As the used stave or lamellae are equally shaped and identical, a rational production of the standards or masts is made possible, also for masts of large heights. The laminated structure is very resistant to crack formations, and also the feature tha the stave elements as required are finger-jointed for achieving the necessary length, is essential for easy and rational provision of high-quality materials, as knots or other weakening irregularities may easily be eliminated.

The poles or standards are manufactured in that the identical lamella elements are glued together after that the individual elements at the outset have been finger-

OMPI jointed in the length in question. By manufacture of larger masts the individual stave or ^' lamella blanks may in advance be made of several sub-lamellae which are glued together in the radial and/or tangential direction of the pole, so that it is ensured that existing demands made on a laminated structure, are satisfied in each individual case, also in connection with particularly long masts having a relatively large diameter at the bottom.

It is also an object of the present invention to provide a machine making it possible to produce the laminated, hollow pole structure according to the invention in a rational and expedient manner.

To this end there is provided a machine comprising a means for feeding stave blanks for machining, and a milling device for shaping the stave blanks, and which is charac¬ terized in that the milling device comprises a pair of milling spindle holders arranged on respective sides of said feeding means and being adjustable at a desired angle relative to each other, for shaping of opposite side faces " of the side blanks by means of milling tools on the milling spindles, one of said spindle holders being arranged to be moved outwards and away from the other spindle holder during feeding of a stave blank and with a speed which is related to the feeding speed of the stave blank, and that means are provided for start and stop of the movement of said spindle holder by actuation from the forward and rearward end, respectively, of a stave blank, together with a means for automatic return of the spindle holder to the initial position by stop of said movement. The invention will be more closely described in the following in connection with exemplary embodiments with reference to the accompanying drawings, wherein

Fig. 1 shows a side view of a pole or standard according to the invention; Fig. 2 shows an end view on an enlarged scale, viewed from the bottom end of the pole;

Figs. 3 and 4 show cross-sections wherein the individual staves consist of sub-lamellae glued together in tangential and radial direction, respectively;

Fig. 5 shows a side view of a machine for manufacturing stave elements for poles according -to the invention, viewed from the feeding end of the stave blanks; and

Fig. 6 shows a sectional view of the machine, essentially along the line IV - IV in Fig. 5.

In figs. 1 and 2 there is shown an exemplary embodi ment of a pole or standard 1 which is composed of twelve elongated, equal stave elements 2 which, such as appears from Fig. 2, have trapezoidal cross-section with mutually parallel inner and outer surfaces, and opposite side faces forming an angle of 30 to each other. Thus, constructed as shown in Fig. 2, the twelve stave elements or lamellae span a full circle (360°) . The staves are glued together along adjacent or abutting side faces, so that there is formed a laminated pole having a centrally extending hollow space or cavity. Th staves are uniformly tapering from the lower end as viewed in Fig. 1, so that an upwards tapering or conical pole 1 is -formed.

For facilitating the jointing of the stave elements in the pole, the side faces of the staves are provided with mutually engaging profiles, e.g. as illustrated in the form o tongue and groove connections 3 , 4. These connections facilitate the joining during assembly of the stave elements. It will be clear that such a pole may comprise a larger or smaller number of staves or lamellae, and that it may be manufactured with large or small conicity or taper, o possibly with constant cross-section when the stave width, i.e. the distance between the side faces of the staves, is constant in the longitudinal direction.

Such as it appears from Fig. 1, a tubular sleeve 5 (shown with dashed lines) is placed on the upper end portion of the pole 1 and is provided with angles or hooks 6 for insulators (not shown) . Further, a sealing top cover 7 is placed on the sleeve. This sleeve, which may be of standar¬ dized design, results in a substantially easier assembly of the insulator holders than previously, at the same time as

OMPI IPO they may be made stronger and better fixed. Further, such a device will preserve and protect the top of the pole against rot.

Such as mentioned above, each of the identical staves or lamellae in the pole may be glued together of one or more sub-lamellae (or constituent or partial lamellae) , so that existing demands applying to a laminated structure with respect to composition and structure, are also satisfied with large pole dimensions wherein the individual stave elements may have a substantial width at the bottom of the pole. In Fig. 3 there is shown a pole cross-section wherein the indi¬ vidual staves or lamellae axe glued together by a pair of sub . or part lamellae 8 and 8 ' juxtaposed in the tangential direction of the pole, and in Fig. 4 there is shown a cross- section wherein the individual staves are glued together by a pair of sub or part lamellae 9 and 9 ' located one outside the other, i.e. glued together in the radial direction of the pole. The number of sub-lamellae may of course also be larger than two, as required. In the cross-section in Fig. - 3, the staves or lamellae are provided with zig-zag guiding profiles 3', 4" for a purpose corresponding to that of the groove and tongue connections 3 , 4 in Fig. 2. Such or similar guiding profiles may also be arranged on the staves in the embodiment according to Fig. 4. A machine for manufacturing or producing staves for the pole or standard described above is shown in Figs. 5 and 6.

The machine is built up on a frame 10 and comprises essentially a means for feeding of stave blanks for processing of machining, a milling device for processing or shaping of the stave blanks and means for operation and control of the feeding and milling devices. The machine is based on electro-pneumatic, or possibly electro-hydraulic operation, and is only schematically illustrated in Figs. 5 and 6, as only the main elements of the machine are illustrated, whereas conventional details which will be known to a person skilled in the art, are omitted. Thus, neither the electric wiring for the machine, nor its pneumatic conduit laying with

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OMPI associated control units, are shown in the Figures.

In Fig. 5 the machine is shown from the feeding or input side, and a processed or machined stave element 11 is shown cross-hatched between a pair of cutter or milling tools 12 and 13, respectively, on respective milling spindle holders 14a and 15a. The stave blank 11 is advanced or fed by means of a feeding means, the left side of the blank in Fig. 5 resting against a longitudinally extending guiding rule 16 which is also shown to be hatched in Fig. 5. The feeding means comprises an endless feeding belt in the form av a chain 17 running over associated sprocket wheels (not more closely shown) and supporting the stave blanks with its upper horizontal belt section. The feeding belt 17 is driven by a feeding motor 18 mounted on the frame 10, the motor being coupled through a belt or chain drive means 19 to a feeding shaft 20 mounted in the frame 10 and o which the driven sprocket wheel of the feeding belt 17 is mounted.

The milling device comprises a pair of milling units 14 and 15 arranged on respective sides of the feeding belt 17, the milling units having milling spindle holders 14 and 15a, respectively, which are inclined towards each other such as shown in Fig. 5, and which may be adjusted at a desired angle relative to each other and to the stave blanks such as more closely described below.

Each of the spindle holders is mounted on a respec¬ tive slide block 21 and 22, respectively, which is in turn slidably mounted on respective, double slide guides 23 and 24, respectively. At their outer ends the slide guides are attached to and supported by respective flanges or brackets 25 and 26, respectively, which are in turn attached, e.g. by welding, to respective, upwards extending columns 27 and 28, respectively, in the machine frame 10, whereas the inner ends of the slide guides are supported by a common supporti element 29.

The left milling unit 14 in Figs. 5 and 6 is in the illustrated embodiment fixed during operation of the machine the slide block 21 being fixedly mounted on the slide guide 23, whereas the slide block 22 of the right milling unit 15 is slidable on the slide guide 24 and is arranged to be moved automatically outwards and away from the other milling unit with a suitable speed in relation to the feeding speed of the stave blanks, so that these get the intended conicity or taper during the milling process.

In order to drive the movable milling unit 15 during its outward movement there is provided a drive belt in the form of a chain belt 30 which extends transversely in relation to the feeding belt 17. This chain belt 30 is driven from the feeding shaft 20 through an angular drive gear 31 and a cog wheel reduction gear 32 connected thereto. The angular drive gear 31 is coupled to the feeding shaft 20 through a belt or chain drive means 33. The reduction gear 32 comprises means (not more closely shown) for variation of the trans¬ mission ratio.

To the slide block 22 of the milling unit 15 there is attached a holder 34 on which there is mounted a clamping means 35 which, under the control of a limit switch or the like, is arranged for automatic connection to and dis¬ connection from, respectively, the transversely extending chain belt 30, i.e. for start and stop, respectively, of the outwards movement of the milling unit. In the illustrated embodiment the clamping means is a pneumatic (or possibly hydraulic) piston/cylinder unit.

The movable milling unit is influenced by a means 36 exerting an inwards directed, resilient pressure force on the milling unit during its outwards directed movement, and causing immediate return of the milling unit to the inner position or initial position as soon as the clamping means 35 is released from the drive belt 30. In the illustrated embodiment the force-exerting means 36 is a pneumatic (or possibly hydraulic) piston/cylinder unit, but a spring or another arrangement may also be used. As previously mentioned, each of the tool spindles of the milling units may be inclined in the milling angle suitable for the chosen number of staves or lamellae in the ^• pole which is to be manufactured. For this purpose each of

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the spindle holders 14a and 15a is releasably mounted on an associated disc or turntable 37 which is fixed to or formed integrally with the respective slide block 21 or 22 and is provided with a circular groove 38 having a T-shaped cross- section wherein the leg of the T constitutes the lead-in opening to the groove. A pair of bolts 39 extending through through-holes in each of the spindle holders such as : suggested in Fig. 6, are in engagement in respective T-groov 38 with their head ends, so that the spindle holders may be fixed in desired position on the turntables 37 by tightening of nuts on the outer free ends of the bolts.

For operation of the tool spindles a cutter drive motor 40 and 41, respectively, is mounted on each spindle holder and is coupled to the associated tool spindle by mean of a suitable belt transmission 42 and 43, respectively. Such as suggested in Fig. 5, a number of spring- loaded pressure rollers 44 are arranged above the feeding belt 17 and press the passing stave blank 11 resiliently downwards against the feeding belt. For the sake of clarity - the arrangement of the pressure rollers is not shown in Fig. 6, but a number of such rollers 44 is arranged along the feeding belt at a suitable distance thereabove. The pressur rollers are mounted in bifurcated holders 45 suspended at suitable intervals along a downwards open channel beam 46 supported by the machine frame 10. The shank portions of the roller holders 45 are passed through apertures in the upper web portion of the channel beam and are also passed through corresponding apertures in a strip-shaped body 47 extending along the channel and preventing the roller holders and thereby the pressure rollers from pivoting in the longi¬ tudinal direction of the feeding belt. The upper, free end of the roller holders is provided with a head (e.g. a nut) limiting the downward movement of the holders, and between the strip body 47 and the upper web portion of the beam 46 there are introduced biassing springs 48 providing for the spring loading of the rollers.

As mentioned above, the connection and disconnection of the clamping means 35 may advantageously take place by i lREΛ OMPI means of suitably mounted limit switches . In Fig . 5 there is shown such a limit switch 49 which is mounted to be actuated by the upper head end of the shown roller holder 45. The arrangement for actuation of the clamping means 35 may advantageously be arranged in such a manner that a first limit switch, such as the switch 49, for activation of the clamping means is operatively connected to a pressure roller immediate¬ ly in front of the milling spindles as viewed in the feeding direction of the stave blanks , whereas a second limit swich for deactivation of the clamping means is operatively connected to a pressure roller immediately behind the milling spindles. In this way the clamping means is connected so that the movable milling unit starts its movement when the forward end of a stave blank arrives at the pressure roller in question, whereafter the clamping means is disconnected and the milling unit is stopped and returned to its initial position when the rearward end of the stave blank passes the pressure roller behind the milling spindles.

In the following the operation of the machine by -machining of a stave blank will be described.

A stave blank 11 which in advance has been cut in a suitable width and has the desired length, and which possiby consists of several sub-lamellae glued together, is brought to rest against the guiding rule 16 and is inserted under the first pressure roller 44. The stave blank is then advanced by the feeding belt 17, and when the stave passes the first limit switch, the clamping means 35 is coupled to the drive belt 30. At the same time as the cutters machine or shape the side faces of the stave blank, the movable milling unit 15 is moved outwards with a speed which is related to the speed of the feeding belt. The pressure-exerting means 36 will keep theunit stable by a suitable force during the movement.

During the feeding the stave element will now get a uniform increase in the width along the whole length of the stave, and this increase may be chosen by changing the ratio between the speeds of the feeding belt 17 and the transver¬ sely extending drive belt 30. When the rearward end of the stave leaves the cutte tools and passes the pressure roller for actuation of the second limit switch, the clamping means is disconnected so that the milling unit 15 stops and is immediately returned to the inner or initial position by the means 36. The machi is then ready to receive another stave blank, regardless the length of the staves.

The conicity-or taper of the staves can be changed a any time, e.g. by exchanging cog wheel in the reduction gear 32 or by utilizing a stepless variator. If another number o staves in the pole is desired, the position angle of the milling tool spindles may be changed to the number of degree which is suitable for a chosen number of staves.

The above described machine represents a preferred embodiment, but it will be clear that many modifications* an structural changes may be made with retention of the princi¬ pal mode of operation. Instead of the illustrated embodimen with drive belt and clamping means it may e.g. be contemplat to use a suitable cam disc or cog wheel arrangement. Furthe ^" it will be clear that the automatic start and stop of the movement of the milling unit may be obtained in many differe ways, either by other forms of limit switch arrangements or in another way.

O PI

Claims

Patent Claims

1. A wooden pole or standard, especially for line carrying in connection with power lines or the like, and

5 comprising a plurality of elongated staves having trapezoidal cross-section with parallel inner and outer surfaces and side faces forming a mutual angle of 360/n degrees, n being the number of staves in the pole, the staves bing glued together along adjacent side faces to form a pole with a centrally

10 extending hollow space, characterized in that all of said staves (2) are equally shaped lamellae in a number which, for- the Cross-sectional dimension of the pole (1) in question, is sufficiently large to achieve a laminated structure in the circumferential direction of the pole, and that the individual

15 lamellae (2) as required are finger-jointed for achieving the desired pole length.

2. A pole according to claim 1, characterized in that the width of the lamellae (2), between the side faces is uniformly decreasing in the longitudinal direction.

•20 3. A pole according to claim 1 or 2, characterized in that the lamellae (2) along their side faces are provided with mutually engaging profiles, such as groove and tongue connection (3, 4) .

4. A pole according to any of the claims 1 - 3,

²⁵ characterized in that it is provided with an essentially tubular metal sleeve (5) which is adapted to and inserted on the upper portion of the pole (1) , and is provided with insu¬ lator holding means (6) attached to the sleeve.

5. A pole according to claim 4, characterized in 0 that the sleeve (5) is provided with a sealing top cover (7) .

6. A machine for manufacturing staves for a wooden pole according to claim 1, comprising a means (17 - 20) for feeding stave blanks (11) for machining, and a milling device (14, 15) for shaping the stave blanks, characterized in that the 5 milling device comprises a pair of milling spindle holders

(14a, 15a) arranged on respective sides of said feeding means (17) and being adjustable at a desired angle relative to each

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^ other, for shaping of opposite side faces of the stave blan by means of milling tools (12, 13) on the milling spindles, of said spindle holders (15a) being arranged to be moved ou wards and away from the other spindle holder (14a) during feeding of a stave blank and with a speed which is related the feeding speed of the stave blank (11) , and that means a provided for start and stop of the movement of said spindle holder (15a) by actuation from the forward and rearward end, respectively, of a stave blank (11) , together with a means automatic return of the spindle holder (15a) to the initial position by stop of said movement.

7. A machine according to claim 6, wherein the feedin means comprises an endless stave blank supporting feeding be (17) driven by a motorized feed shaft (20) , characterized in that there is provided a drive belt (30) extending trans¬ versely to the stave blank feeding direction, which drive be is driven by the feeding shaft (20) through a cog wheel redu gear (32) and is arranged to drive said movable spindle hold (15a) in its outwards directed movement.

8. A machine according to claim 7, characterized i that the spindle holder (15a) is mounted on a slide block (2 which is slideable on a horizontal slide guide (24) and on which slide block (22) there is mounted a clamping means (35 which is arranged for automatic connection with, respectivel disconnection from, said transversely extending drive belt ( for start and stop, respectively, of the outwards directed movement of the spindle holder (15a) .

9. A machine according to claim 8, characterized in that it comprises a means (36) exerting in inwards- directed force on the spindle holder (15a) during its outwards direct movement, and causing immediate return of the spindle holder

(15a) to its initial position by release of the clamping mea (35) from the drive belt (30) .

10. A machine according to claim 9, characterized in that the force-exertiήg means (36) is a pneumatic or hydraul piston/cylinder unit.

11. A machine according to any of the claims 8 - 10, characterized in that the clamping means (35) is a pneumati or hydraulic piston/cylinder unit which is arranged to be activated or deactivated by means of respective limit switches actuated upon passage of the forward and the rearward end, respectively, of a stave blank (11) .

12. A machine according to claim 11, wherein a plurality of spring-loaded pressure.rollers (44) are arranged above the feeding belt (17) , and by passage of a stave blank (11) press the blank resiliently downwards against the feeding belt (17) , characterized in that a first limit switch (49) for activa- tion of the clamping means (35) is operatively connected to a pressure roller (44) immediately in front of the milling spindle holders (14a, 15a) as viewed in the feeding direction of the stave blanks (11) , and a second limit switch for de- activation of the clamping means (35) is operatively connected to a pressure roller (44) immediately behind the milling spindle holders.

13. A machine according to any of the claims 8 - 12, characterized in that each spindle holder (14a resp. 15a) is pivotally mounted on a turntable (37) by means of releasable bolts (39) engaging in and fixable in a desired position in a circular groove (38) formed in the turntable (37) .

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