US 3902539 A
Apparatus for centering the longitudinal axis of a log on a reference axis comprises two scanning or sensing devices which determine the horizontal and vertical deviation of the longitudinal axis from the reference axis and which sense the log in each case at two sensing points, and a device controllable by the sensing devices for aligning the log in the vertical and horizontal directions corresponding to the signals supplied by the sensing devices.
Description (OCR text may contain errors)
United States Patent [191 Ketteler [4 1 Sept. 2, 1975 APPARATUS FOR CENTERING THE LONGITUDINAL AXIS OF A LOG ON A REFERENCE AXIS  Inventor: Otto Ketteler, Bad Iburg, Germany  Assignee: C. Keller u. Co., Laggenbeck,
Germany  Filed: Jan. 2, 1974 21 Appl. No.: 430,090
 Foreign Application Priority Data Feb. 8, 1973 Germany 2306214  US. Cl 144/209 A; 82/2.5; 82/45; 356/ 167  Int. Cl. B27L 5/02; B23B 23/00  Field of Search 82/2.5, 45; 356/167; 144/209 R, 209 A  References Cited UNITED STATES PATENTS 7/1968 Brookhyser et a1 82/45 X 3,504,719 4/1970 82/45 X 3,664,395 5/1972 Reed... 144/209 A 3,712,741 1/1973 Revert 356/167 X 3,746,065 7/1973 Mason 144/209 A X 3,752,201 8/1973 I-Ieth 144/209 A FOREIGN PATENTS OR APPLICATIONS 1,913,965 9/1970 Germany 144/209 A 1,913,964 9/1970 Germany 144/209 A Primary Examiner-Donald R. Schran Assistant Examiner-W. D. Bray [5 7] ABSTRACT Apparatus for centering the longitudinal axis of a log on a reference axis comprises two scanning or sensing devices which determine the horizontal and vertical deviation of the longitudinal axis from the reference axis and which sense the log in each case at two sensing points, and a device controllable by the sensing de vices for aligning the log in the vertical and horizontal directions corresponding to the signals supplied by the sensing devices.
15 Claims, 4 Drawing Figures AVAF/Af/AYAY w 8 PATENT SEF 2197s sum 1 or 4 Fig.1
PATENTEB SEP 2 I975 SHEET 2 BF 4 W A y PATENTED SEP 2 I975 SHEET 3 0F 4.
APPARATUS FOR CENTERING THE LONGITUDINAL AXIS OF A LOG ON A REFERENCE AXIS An apparatus for centering the longitudinal axis of a log on a reference axis is used in particular for centering logs or round wood pieces to be further processed in a veneer peeling machine. The centering apparatus is intended to determine the optimum centering points for clamping the wood in the veneer peeling machine with respect to the natural curvature of the log.
In a known centering apparatus for timber the article whose longitudinal axis is to be centered on a reference axis, i.e. in this case a length of round wood, is supported by a device which serves to align the article in the vertical and horizontal directions and which comprises substantially two spaced. independently actuable. vertical lifting devices each comprising an element which supports the article at two points. Each vertical lifting device is supported in a carriage by which such lifting devices can be displaced in a horizontal direction transversely of the reference axis. The known centering apparatus also comprises within the region of each end of the article a sensing device which scans or senses the article at two diametrically opposite sensing points (at the periphery). Each sensing device comprises two arms engaging round the article, such arms being pivotally mounted at a central axis and connected together for joint pivotal movement via tooth segments; the substantially coplanar angled arms may be pivoted about the middle axis of the central axis so that they can sense the article on the one hand in the vertical direction and on the other in the horizontal direction. Whereas the one sensing arm is made on the whole rigid. the leg of the other sensing arm coming into contact with the article is movable between two fixed end positions. To pivot and rotate the arms several separate drive means are provided.
To center an article with this known apparatus the article is first aligned in the vertical direction by setting the sensing arms of the two sensing device perpendicular to each other. the article then firstly being aligned in the vertical direction in accordance with the signals supplied by the two sensing devices (which each control a lifting device). After this vertical alignment the sensing arms of the sensing devices are pivoted about the central axis through 90 so that a horizontal alignment may be effected, the signals now supplied displacing the vertical lifting devices on their carriages, thus horizontally aligning the article.
As is apparent from the foregoing description of the mode of operation of the known centering apparatus (firstly vertical alignment of the article and then horizontal alignment, after switching over the sensing devices) the centering operation is extremely complicated and time consuming. Furthermore, the known centering apparatus involves a considerable amount of expenditure, both as regards the structure and as regards the production costs. The complicated construction also has the disadvantage that the apparatus must be very carefully maintained to ensure that in particular the sensing arms function satisfactorily.
The principal object of the invention is to provide a centering apparatus especially adapted to center articles such as logs to be peeled for veneer and which, in spite of a relatively simple construction, permits rapid and reliable centering of such articles.
According to the invention this object is realized in that the two sensing points of each sensing device inelude a peripheral angle of less than and the device for alignment corresponding to the signals supplied by the two sensing devices is simultaneously actuable in the sense of a vertical and a horizontal alignment.
Where the sensing devices of centering apparatus according to the invention approach the periphery of the article to be sensed and such article is not aligned, one sensing point of at least one sensing device will detect the article and then supply a corresponding signal by which the device for aligning the article is then correspondingly moved horizontally. Thereafter, the vertical movement of the aligning device may be continued until at least one sensing point again provides a detection signal. This again results in a corresponding horizontal movement of the alignment device and thus in a further alignment or centering of the article. These aligning operations are continued until both sensing points of the sensing devices detect the article. which indicates that the longitudinal axis of the article is centered in the desired manner on a reference axis.
The alignment operations described are effected very rapidly in succession without appreciable delay and consequently rapid centering of the article is ensured.
The apparatus according to the invention may be of relatively simple construction and the production costs of such an apparatus are thus comparatively low. The simple structure of said apparatus also means that relatively little expenditure is involved in the maintenance.
An embodiment of the invention is illustrated in the accompanying schematic drawings, wherein:
FIG. 1 is an elevational view of the centering apparatus; and
FIGS. 2-4 are sectional views along the line llIl of FIG. 1 illustrating three different working positions when centering a piece of round timber.
The longitudinal axis A of a length of round timber I is to be centered on a reference axis with respect to the natural curvature of the round timber in order to give the optimum centering points at the end faces of the timber so that, after centering, the timber can be clamped for a further operation by a veneer peeling machine, for example.
In the disclosed embodiment the timber l to be centered is supplied by a feed means 2 to the working vicinity of the apparatus. This feed means 2 may for example be two endless convcyor belts, chains or the like running adjacent and parallel to each other and made in the usual manner.
Provided beneath the feed means 2 are two vertical adjusting or lifting devices 4 which are accommodated in a pit 3 and which may be independently operating hydraulic cylinder-piston means whose lifting rams 4a comprise at each of the upper ends a support prism 5 constructed as a two-point support element and comprising support faces 5a and 5b. The support faces 5a and 5b of each prism 5 are arranged substantially symmetrically to each other and form an included angle of less than 180 so that they engage the timber 1 from below at two support points. Each of the two vertical lifting devices 4 is articulately mounted, in the present case at the lower end, in such a manner that they can be pivoted about a joint horizontally extending axis a lying parallel to the reference axis, thereby enabling adjustment of the supports transversely of the latter axis.
For this pivotability each vertical lifting device 4 is articulately connected in the region of its upper cylinder end to a horizontal adjusting device 6 which in turn is articulately mounted, at its other end, to a wall 3a of the pit 3 (cf. FIGS. 2-4). These horizontal adjusting devices 6 may also be fluid-operated cylinder-piston means.
Each adjusting device 4 and 6 is supplied with operating fluid by means of a pump P via electrically controlled valving V, V of known kind operable to extend and retract the pistons of the respective devices.
The vertical lifting devices 4 (with their support prisms 5) and the horizontal adjusting devices 6 represent the most important parts of an apparatus for aligning the timber l in a vertical and horizontal direction.
Arranged fixedly adjacent the pit 3 and longitudinally of the feed means 2 are two vertical supports or posts 7, 8 (on both sides of the conveying means). Disposed on each post 7, 8 is a carriage 9 and 10 respectively which can be displaced on the associated post in the vertical direction. Rigidly secured to each carriage 9, 10 is a substantially horizontally extending cantilever arm in vertical alignment with the reference axis. The two cantilever arms 11, 12 extend towards each other and are in alignment.
Each cantilever arm 11, 12 carries a sensing device 13 and 14 respectively which can be moved horizontally along the associated arm. For this purpose each arm 11, 12 is equipped with a screw spindle 15, 16 which may be driven by an associated gear motor M and M respectively. The sensing devices 13, 14 are slidingly mounted on the arms 11, 12 by slide blocks 17, 18 which also include a corresponding connection to the spindles l5, 16.
The horizontal displaceability of the sensing devices 13, 14 enables the latter to be set to the optimum longitudinal regions of the round timber 1 to be measured. Regions within about 100 mm from the end faces of the article to be measured have been found to be favorable sensing regions.
As is further apparent in particular from FIGS. 2 to 4, each sensing device 13, 14 comprises two spreading arms 19, and 21, 22 respectively which are made symmetrical with respect to each other and diverge downwardly substantially prismatically and in this embodiment are each formed by two struts to provide greater twisting resistance.
Provided on each sensing device 13, 14 are two sensing members which in each case determines a sensing point which senses the timber 1 at its periphery. In the disclosed embodiment the sensing members are each an electrical switching photocell F arranged on a spreading arm (for example 19, 20) and a cooperating light source S at the free end of the other spreading arm (for example 20, 19). In each sensing device 13, 14 the light beams L directed from the light sources S to the associated photocells F intersect below the corresponding spreading arms in such a manner that the lower sections containing the two sensing points of each light beam include between them an angle a of less than 180. The light sources may be suitably constructed and aligned mirrors S which are mounted at the free ends of the spreading arms 19, 20 and 21, 22 with the aid of support plates 23, 24 and 25, 26, respectively.
The two sensing devices 13 and 14 operate independently of each other and cooperate with the vertical lifting device 4 (including its horizontal adjusting device 6) disposed on the same side, the sensing devices controlling the lifting devices in the sense of a vertical and horizontal alignment of the article to be centered, i.e. in this case the timber l. The sensing devices 13, 14 and the associated lifting rams 4a and their support prisms 5 are connected to each other in such a manner that they may be moved in opposite directions, i.e. when for example the vertical lifting devices move an article to be centered vertically upwardly the sensing devices 13, 14 move via their arms ll, 12 and the carriages 9, 10 on the corresponding posts 7, 8 downwardly so that the timber 1 may be scanned by the sensing members. To connect the lifting rams 4a with the carriages 9 and 10 roller chains, cables or the like may be provided as indicated at 27 and 28, which are guided by means of corresponding rollers. To facilitate the displacing of the arms 11 and 12 and their carriages 9 and 10 on the posts 7 and 8 balance weights 31, 32 are provided on chains or the like 29, 30, the latter also being led in suitable manner over guide rollers.
The photocells F of one sensing device are electrically coupled to the valve V of the associated vertical lifting device 4 and to the valve V of the related horizontal adjusting device 6 in such manner that, when both light beams L are uninterrupted, the piston 4a of the device 4 is driven upwardly. When either light beam L is interrupted, upward movement of the piston ceases and, depending on which beam L is interrupted, the associated adjusting device 6 will be either extended or contracted. The other sensing device has its photcells F similarly coupled to the valves of the other adjusting devices 4 and 6.
A centering operation will be described hereinafter with reference to FIGS. 2 to 4.
The timber 1 to be centered is conveyed by the feed means 2 to the pit 3 and engaged by the support prisms 5 from below and lifted off the feed means 2. As particularly clearly apparent from FIGS. 2 to 4, the vertical lifting devices 4 are in their vertical positions in alignment with the posts 7 and 8 so that in this condition the support prisms 5 are also symmetrical to the spreading arms 19, 20 and 21, 22 respectively of the associated sensing devices 13, 14. When the vertical lifting devices 4 or their support prisms 5 have raised the timber 1 from the feed means 2 (cf. FIG. 3) they continue their vertical upward movement. Due to the connection between the sensing devices 13, 14 and the associated support prisms 5 these elements are moved vertically towards each other until at least one beam L of one sensing device senses the timber 1, whereupon the ray path from the corresponding source S to the associated photocell F is interrupted or occupied. The resulting signals actuate the corresponding horizontal jack or adjusting device 6 in such a manner that the vertical lifting device is pivoted about its axis a and thus the timber 1 is adjusted horizontally. After this adjustment operation the light beam path from the source S to the photocell F is again free and consequently the vertical approach of the sensing devices 13, 14 to the timber 1 may be continued. As soon as at least one of the beams is interrupted by the periphery of the timber 1 the horizontal adjusting movement described above is repeated. These adjustment operations in the vertical and horizontal direction (in accordance with the signals supplied by the sensing devices 13, 14) are repeated until all of the light beam paths to the photocells F in the scanning devices 13 and 14 are occupied. The timber l is now scanned by the sensing devices l3, 14 at two sensing points T and T spaced by a peripheral angle B with reference to the timer 1 of less than 180. That is, the moving points lie on an arc of less than 180. These sensing points T T are in the lower portions of the intersecting light beam L. The longitudinal axis A of the timber l is now exactly aligned on the reference axis. Using the optimum centering points determined in this manner (at the two end faces of the round timber l) the timber may then be clamped in a veneer peeling machine for further processing. timber beams In the centering operation described on the basis of the signals supplied by the two sensing devices 13, 14 a vertical and horizontal alignment of the support prisms 5 (and of the lifting means carrying them) on which the timber 1 rests is effected simultaneously. Since the aforementioned brief alignment operations may follow each other in practice relatively rapidly, the apparatus according to the invention permits a very rapid centering of the timber 1.
The apparatus according to the invention is of relatively simple construction, which also reduces production costs and makes maintenance simple.
Various modifications of the centering apparatus described are of course possible within the scope of the invention, including embodiments suitable for centering elongated articles other than the round timber length for a veneer peeling machine referred to in the example. For sensing the article to be centered, instead of the photocells other feeler members may be employed containing electrical limit switches actuated for example via chains, cables or other flexible elements on contact with the article; the chains, cables or the like would then be substantially equivalent to the light beams of the photocells.
1. Apparatus for centering the longitudinal axis of an article on a reference axis comprising a pair of supports spaced along said reference axis for supporting an article with its longitudinal axis substantially horizontal; means mounting each of said supports for independent vertical movement and for independent movement transversely of said reference axis; a pair of article sensing devices; means mounting said sensing devices in a position in which either of the latter is operable to sense an article supported by said supports; and adjusting means responsive to the operation of either one of said sensing devices to effect individual adjustment of said supports vertically and transversely of said reference axis.
2. Apparatus according to claim 1 wherein said supports comprise a pair of independent members each of which is pivotal about a pivot axis parallel to said reference axis.
3. Apparatus according to claim 2 wherein said adjusting means is operable to rock said members about said pivot axis.
4. Apparatus according to claim 1 including means for effecting relative vertical movement of said supports and said sensing devices in a direction toward one another.
5. Apparatus according to claim 1 wherein said sensing devices define two sensing points located on an arc of less than 6. Apparatus for centering the longitudinal axis of an elongate article on a reference axis comprising a pair of independent supports spaced from one another along said axis a distance to support such article adjacent opposite ends of the latter; means mounting said supports for independent adjustment vertically and transversely of said reference axis; a pair of sensing devices spaced from one another along said reference axis and each of which defines two sensing points lying on opposite sides of said reference axis; means mounting said sensing devices in a position in which each of said sensing points is operable to sense the presence of an article on said supports; and a pair of independent adjusting means connected to each of said respective supports for adjusting the latter vertically and transversely of said reference axis, one of said adjusting means being responsive to operation of either sensing point of one of said sensing devices to adjust one of said supports vertically and transversely of said reference axis and the other adjusting means being responsive to operation of either sensing point of the other of said sensing device to adjust the other support vertically and transversely of said reference axis.
7. Apparatus according to claim 6 wherein said sens ing devices are mounted at a level above said supports, and including means for adjusting said sensing devices vertically.
8. Apparatus according to claim 7 wherein the means for adjusting said supports and said sensing devices effects simultaneous vertical movement of said supports and said devices in opposite directions.
9. Apparatus according to claim 6 wherein the mounting means for said sensing devices includes horizontal arm means on which said devices are movable horizontally.
10. Apparatus according to claim 9 wherein said arm means are in substantial alignment with said reference axis.
11. Apparatus according to claim 6 wherein each of said sensing devices includes a pair of substantially prismatically open spreading arms confronting said sup ports.
12. Apparatus according to claim 6 wherein each of said sensing devices includes electrical switching means.
13. Apparatus according to claim 6 wherein each of said sensing devices includes a pair of spreading arms extending on opposite sides of said reference axis; a photocell carried by each of said arms; and a light source carried by each of said arms, the light source of one of said arms being capable of establishing a first light beam to the photocell of the other of said arms, and the light source of the other of said arms being capable of establishing a second light beam to the photocell of said one of said arms.
14. Apparatus according to claim 13 wherein said first and second light beams intersect.
15. Apparatus according to claim 13 wherein said arms extend along downwardly diverging lines forming an included angle therebetween of less than 180.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,902,539 Dated September 2, 1975 Inventor(s$ OttO Ketteler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 5, line 3, change "timer" to -timber--.
Column 5, line 11, delete "timber" Column 5, line 12, delete "beams" Signed and fieale d this twenty-fifth Day of November 1975 [SEAL] A ttes t.
RUTH C. MASON C. MARSHALL DANN ff Commissioner ofPalenrs and Trademarks