US2973793A

US2973793A - Process of straightening crooked wooden poles and piles

Info

Publication number: US2973793A
Application number: US771115A
Authority: US
Inventors: John M Irvine
Original assignee: Koppers Co Inc
Current assignee: Beazer East Inc
Priority date: 1958-10-31
Filing date: 1958-10-31
Publication date: 1961-03-07
Anticipated expiration: 1978-03-07

Description

March 7, 1961 J. M. IRVINE 2,973,793

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a 'r TaEJ/LYI Ufllt PROCESS OF STRAIGHTENING CROOKED WOODEN POLES AND PILES John M. Irvine, Wexford, Pa., assignor to Koppers Company, Inc., a corporation of Delaware Filed Oct. 31, 1958, Ser. No. 771,115

12 Claims. (Cl. 144-327) considered as a possible bole to be cut into a pole for,

use as a utility pole, pile or fence post. This invention further relates only to such wooden items as aforesaid that are to be given conventional pressure treatments with steam or-hot liquid preservatives in cylinders or autoclaves. The preservatives are usually creosote, creosote solutions, penta chlorophenol in petroleum or creosote, or other oil borne preservatives or water borne preservatives.

- More particularly, the present invention comprises a process for straightening these crooked ,wooden poles, piles or fence posts hereinafter termedpoles, in which the plasticizing conditions inherent in the conventional preservative treatments are combined with restraint on the poles until they have cooled, after the preservative treatment, to a stage at which the fibers around the outermost periphery of the poles are dried to a state below their saturation point for a depth of at least A", at which time they have achieved permanent improvement in straightening.

The primary object of the present invention is to provide a practicable, economical and permanent method of improving the straightness of crooked wooden poles by utilizing the conditions inherent in the conventional pressure treating cylinders, i.e., steam conditioning for the pressure impregnation and/or the use of hot preservatives.

The steaming or soaking of small wooden parts for curving them for use in furniture, boat ribs, etc., is an ancient art. However, none of the efforts to straighten wooden poles made from the bolesof crooked trees have been satisfactory prior to this invention. Theprior art eiforts to improve the straightness of crooked wooden poles have included the following:

Crooked poles are stacked prior to the preservative treatment for seasoning with the bow vertical and with I other poles stacked on top so that their weight against the bow removes some of the crook. Unfortunately, as soon as these temporarily straightened poles are given the preservative treatment, the plasticizing conditions in the cylinder cause the pole to relax into its former crooked condition.

Another method attempted has been to so load the crooked poles on the trams going into the treating cylinder that the Weight of other poles above them on the vertical bow causes them to straighten temporarily. However, when thesepoles are removed from the cylinder and the trams, immediately after treating or before they are thoroughly cooled, they are still plastic and tend to resume their original crooked state. In fact, .unless properly supported while'hot, they may develop additional crooks.

The present invention gives quite different results with the wooden poles cut from the boles of crooked trees.

Patented Mar. 7, 1951' 2 It capitalizes on the conditions withiuthe treating c'ylinde'r which plasticize the poles, to achieve a permanent improvement in the straightness of such crooked poles. The degree of plasticity given wood in the cylinder is constructively used on the crooked poles, rather than wasted.

In order to accomplish this, the crooked woden pole, either prior to impregnation, or when more plastic during, or shortly after, the preservative treatment, is advantageously placed against an abutting member in the form of a straight member, or another crooked pole, and pressure is applied to force the crooked parts of the wood of the pole toward the general line of theaxis of the pole, to forcibly remove all or part of the crook. Since some spring back may be expected, it is possible to overbend by utilizing checks or blocks at appropriate places. For example, steel bands may be put around crooked wooden poles, with the crooks opposite each other, and these bands then pulled up tensioning machines to straighten the crooks. These bands are left-on the poles until they have thoroughly cooled after the cylinder treatment. When the poles are thoroughlycool the escaping heat stored in the wood during treatment will havedried the outer shell area of the wood below the fiber saturation point and the pole will be set in its straightened position. While there may be some spring back even then, there will have been material permanent reduction of the crook. Surprisingly, the poles do not have to be thoroughly dried in the restraining bands, only cooled. H

Measurements were taken as follows of the moisture content of the exterior of some poles by A increments:

Moisture content Since the fiber saturation point of poles that are con ventionally cut from the boles of trees is generally 27- 31% moisture, it appears that the outer A dried Well below this saturationpoint during the cooling treatment under'restraint. From this invention the inventor reasons that when the poles are held under restraint until only this outer shell of wood is dried below the fiber saturation point, this outer shell becomes stiff enough to thereafter control the pole in its straighter condition, with the restraining bands removed, even though the remaining inner portions toward theheart of the bole is somewhat plastic, due to the fibers being above their saturation point.

The novel use of'restraint, as by means of the bands on the crooked portions of wooden poles in this abutting manner, during the cooling of the .pres'sure treated poles until the outer A" or more of the peripheral surface of the cut boles is dried below the saturation point of it'sfibers there, has several beneficial effects:

It has been found unexpectedly easy to improve the straightness of crooked poles. in the aforesaid manner.

Preferred mode of operation is to take two or more crooked poles of suitable conventional size, place them together so the crooks can be pulled out by forcing the poles together, or by means of a block in between to overbend the poles to allow for a certain amount of spring back, restraining the poles in this straighter position by means of bands, cable, chains or other means. The poles, st ll held together, are steamed in the cylinder as is normal for conditioning them for preservative treatment and treated with the hot preservative, then allowed to cool before removing the bands.

In addition to the general objects recited above, the innvention has for further objects such other improvements and advantages in process and product as may be found to obtain from the following description thereof, taken in connection with theaccompanying drawings, diagrammatically illustrating a few forms of carrying out the invention:

Q'Figure 1 shows diagrammatically a conventional system for heat preservative pressure treatement of poles;

Figure 2 is a schematic view illustrating poles stacked to press out bow in seasoning, prior to heat preservative treatment, in which the results are only temporary;

Figure 3 is a view illustrating two actual crooked poles prior to straightening;

Figure 4 is a view of the same poles with intermediate blocks and bands prior to applying the restraint;

Figure 5 is a view of the same poles with the restraint applied prior to heat treatment;

Figure 6 is a view of these same actual poles straightened after the heat treatment and after the cooling of the same with the restraint applied and the bands then removed.

Figures 7 to 10 are schematic views of two crooked poles before straightening, after interposition of blocks for overbending, as tightened and steamed and liquid preservative treated, and straightened after cooling;

Figures 11 to 13 are schematic views illustrating the use of straights with a crooked pole before, during, and after cooling.

The same reference numerals are used for like parts in each of the several views.

Referring to the drawings, the wood preserving treatment which provides the heat and plasticity in the poles, that is novelly employed with the present invention, in conjunction with restraint on crooks in poles until they cool, for converting crooked poles to straights meeting or bettering the classical standard specifications set by the American Standards Association, is carried out in any one of the conventional manners, by loading the poles on trams or cars and running them into a treating cylinder 10, wherein the poles are steamed under pressure to saturate the fibers of the outer periphery of the poles, and to penetrate the mass of the wood with heat, to store the same for subsequent drying out of the fibers at the outer periphery of the poles to a point below their fiber saturation point, after the poles are removed for cooling.

Generally, after conditioning the poles with steam, preservative is introduced under pressure, and this places air previously stored in the wood under a pressure which is relied on, when the pressure is released, to expel excess preservative from the wood.

The preservative is unuslly fed from a Work tank 11 to the treating cylinder 10 by a pressure pump 12 and under control of an adjustable flow control 14. Upon release of pressure, the excess preservative flows back in cycle to the work tank, all as described, for example in Herman US. Patent No. 2,668, 779, of 1954.

For more permanently straightening the crooks in such poles of the class generally employed as utility poles, piles, and posts, in lieu of the prior art general procedure of stacking crooked poles, as illustrated in Figure 2, to press out the bow in seasoning the wood, which results in only temporarily in straightening the poles, the present invention applies an abutting force to the crook portion of the pole while its outer periphery is above the saturation point of the fibers and the mass of the pole is still 4 hot from the heat and wood preservative treatment, to force the crooked section toward the general axis of the pole, and maintains the straightened pole in this restrained position until the heat treated pole is cooled after said heating and treatment to a state at which the saturated fibers at the periphery of the straightened crooked portion are dried below their saturation point by the outflow of heat from the mass of the pole.

In accordance with the present process, two actual crooked poles 13, as the two shown in Figure 3, with bows therein before straightening, have blocks 15 placed between them as shown in Figure 4, so that they can be over bent by bands 16 in order to allow for spring back. The poles are tightened by the bands as shown in Figure 5 and remain in this position relative to each other during steaming, and liquid preservative treatment under pressure in the cylinder 10, and thereafter until cooled as aforesaid. After such cooling, the bands are removed and the poles are permanently straightened as shown in Figure 6.

Figures 7-10 show a similar way of straightening two poles 13 with a single intermediate block and bands at opposite ends, the respective figures showing the original sweep or crook, the poles ready for tightening of the bands, the over bent position of the poles with the bands tight, and the straightened poles after cooling as aforesaid.

Figure 11 shows a straight member, which can be of steel, wood, or other material and a crooked pole to be straightened without the interposition of a block, and Figure 12 shows the band in place tightened up, and the two are treated in the cylinder 10 in this, and later cooled while still in this, drawn up relation.

Figure 13 shows these two members after cooling with the band removed. The pole 13 is straightened and there has been some spring back in the original crooked pole 13, since it was not over bent.

The invention is not limited in scope to the exact procedure just described. For example, poles can be staightened between the steaming period and the pressure period of the treating operation, or they can be straightened immediately after the liquid preservative treating operation while still plastic and left restrained in the straighter position until cooled.

The invention as herein-above set forth is embodied in particular form but may be variously embodied within the scope of the following claims.

I claim:

1. A process for combined preservative treatment and straightening of wooden poles suitable for utility or building poles, piles or fence posts cut from holes of trees and having crooks therein, comprising: forcing heat into the wood of a said pole under pressure in the form of at least one of the group consisting of steam for conditioning of the wood for preservative treatment and hot liquid preservative until at least 4" of its outer periphery is above the saturation point of the fibers, and treating the so-heated poles with impregnant; applying an abutting force to the crook portion of the pole while the /3" outer periphery is above the saturation point and the mass of the pole is still hot from the aforesaid heat treatment and thus forcing the crooked section toward the general axis of the pole; and maintaining the thusstraightened crooked portion of the pole in this restrained position until the heat treated pole is cooled after said heating and preservative treatment to a state at which the saturated fibers of the A periphery of the straightened crooked portion are dried below their saturation point by the outflow of heat from the mass of the pole and thereupon removing the restraint from the poles.

2. A process as claimed in claim 1, and in which the restraint is applied to the pole prior to, and during, the heat treatment, as well as during the cooling of the pole after the heat treatment.

3. A process, as claimed in claim 1, and in which the restraint is applied to the pole soon after the heat treatment and while the wood is still plastic therefrom, as well as during the cooling of the pole.

4. A process as claimed in claim 1, and in which the poles so treated as ones whose outer peripheries are below the fiber saturation point before they are subjected to the aforesaid heat treatment.

5. A process for combined preservative treatment and straightening of wooden poles suitable for utility or building poles, piles, or fence posts cut from the boles of trees and having crooks therein, comprising: applying another member in abutting relation to a crooked pole and drawing the member and the pole together so as to exert an abutting force to the crook portion of the pole and forcing the crooked section toward the general axis of the pole; forcing heat into the wood of a said pole under pressure in the form of at least one of the group consisting of steam for conditioning of the Wood for preservative treatment and hot liquid preservative and treating the so-heated poles with impregnant, whereby at least the outer A" of the peripuhery of said crooked pole is brought above the saturation point of the fibers while the mass of the crooked pole is still under the aforesaid crook straightening abutting force and maintaining the straightened crooked portion of the pole in this restrained position until the heat treated pole is cooled after said heating and preservative treatment to a state at which the saturated fibers of the A" periphery of the straightened crooked portion are dried below their saturation point by the outflow of the heat from the mass of the pole, and thereupon removing the member from said abutting relation with the cooled straightened pole.

6. A process as claimed in claim 5, and which includes the steps of applying another member in abutting relation to the crooked pole and drawing the member and the crooked pole together so as to exert the aforesaid abutting force to the crook portion of the pole and force the crook section toward the general axis of the pole.

7. A process as claimed in claim 6, and which also includes the step of including chocks between the abutting members with overbending of the poles during the aforesaid cooling of the poles.

8. A process as claimed in claim 6, and in which said another member is another pole, and in which the poles are drawn together by tieing means encircling the poles and drawn tightly around the poles.

9. A process for straightening of wooden poles suitable for utility or building poles, piles, or fence posts out from holes of trees and having crooks therein, comprising: foreing heat and moisture into the wood of a said pole until a tleast A" of its outer periphery is above the saturation point of the fibers; applying an abutting force transversely of the axis of the pole to the crook portion of the pole intermediate its length while the A outer periphery is above the saturation point and the mass of the pole is still hot from the aforesaid heat treatment and thus forcing the crooked section toward the general axis of the pole; and maintaining the thus-straightened crooked portion of the pole in this restrained position until the heat treated pole is cooled after said heating to a state at which the saturated fibers of the A" periphery t of the straightened crooked portion are dried below their saturation point by the outflow of heat from the mass of the pole and thereupon removing the restraint from the poles.

10. A process as claimed in claim 9, and which includes the steps of applying another member in abutting relation to the crooked pole and drawing the member and the crooked pole together so as to exert the aforesaid abutting force to the crook portion of the pole and force the crook section toward the general axis of the pole.

11. A process as claimed in claim 10, and which also includes the step of including chocks between the abutting members with overbending of the poles during the aforesaid cooling of the poles.

12. A process as claimed in claim 10, and in which said another member is another pole, and in which the poles are drawn together by tieing means encircling the A poles and drawn tightly around the poles.

References Cited in the file of this patent UNITED STATES PATENTS 53,610 Hanvey Apr. 3, 1866 316,961 Hansen et al. May 5, 1885 1,250,480 Marten et al. Dec. 18, 1917 1,330,804 Haskell et al. Feb. 17, 1920 2,668,779 Herman Feb. 9, 1954 FOREIGN PATENTS Bending Solid Wood to Form, US. Dept. of Agriculture, Forest Products Lab., No. 1764, p. 12, July 1955.