DEVICE FOR CENTERING OF TIMBER BLOCKS AND THE LIKE
United States Patent 3858631
A device for centering timber blocks or the like when being fed into sawing machines, in which centering means, swingably disposed for working on opposite sides of the blocks, are so coupled that they move from a normal position outwards from each other or inwards towards each other an equal distance, coupling of the centering device being achieved by means of one or more chains, bands or the like which run in opposite directions over chain wheels or the like attached to the centering means, and a spring device which determines the normal position if coupled with at least one of the centering means. The spring device consists of a screw and a nut working in conjunction with it as well as a spring mounted on the screw between the nut and a stop, which screw is given more or less tension by turning of the nut. The screw is connected to an arm mounted on the centering means, through a nut, which is penetrated by the screw. The screw is to be turned in relation to the nut in order to set the starting position of the centering means.
US Patent References:
/1295875.html
Eaglesfield - March 1919 - 1295875
Feeding mechanism
Richardson - August 1939 - 2169394
Log-centering barker feeding mechanism
Annis, Jr. - August 1959 - 2897859
Modular conveyor
Leonard - February 1964 - 3120303
/1295875.html
Eaglesfield - March 1919 - 1295875
Feeding mechanism
Richardson - August 1939 - 2169394
Log-centering barker feeding mechanism
Annis, Jr. - August 1959 - 2897859
Modular conveyor
Leonard - February 1964 - 3120303
Inventors:
Andersson, Per Lief (Farila, SW)
Lind, Rune Sigfrid (Farila, SW)
Lind, Rune Sigfrid (Farila, SW)
Application Number:
05/399495
Publication Date:
01/07/1975
Filing Date:
09/21/1973
View Patent Images:
Export Citation:
Assignee:
Skogsagareforeningen, Mellanskog U. P. A. (Gavle, SW)
Primary Class:
Other Classes:
198/416, 144/250.150, 144/246.100
International Classes:
B27B1/00; B27B31/06; B27B31/00; B27B31/00
Field of Search:
198/204 144/28R,28E,242R,242C,246R,246A,246F,249R,249B 83/436
Primary Examiner:
Juhasz, Andrew R.
Assistant Examiner:
Bray W. D.
Attorney, Agent or Firm:
Cushman, Darby & Cushman
Claims:
We claim
1. In apparatus for centering timber blocks or the like being fed into sawing machines centering means including assemblies swingably disposed for working on opposite sides of a block, means coupling said assemblies so that they move from a normal position outwards from each other or inwards towards each other an equal distance, said coupling means including at least one endless member running in opposite directions over wheels or the like attached to said assemblies means, and a spring device which determines the normal position coupled with at least one of said assemblies and including a screw and a cooperating nut and a spring mounted on the screw between the nut and a stop so that the screw may be tensioned by turning of the nut, said screw being connected to an arm mounted on said one assembly by a nut which is penetrated by said screw, said screw being turned in relation to the nut in order to set the starting position of the centering means.
2. Apparatus as in claim 1 wherein said spring device can be adjusted not only in respect to the tension of the spring but also for adjusting the normal spacing of the centering means.
1. In apparatus for centering timber blocks or the like being fed into sawing machines centering means including assemblies swingably disposed for working on opposite sides of a block, means coupling said assemblies so that they move from a normal position outwards from each other or inwards towards each other an equal distance, said coupling means including at least one endless member running in opposite directions over wheels or the like attached to said assemblies means, and a spring device which determines the normal position coupled with at least one of said assemblies and including a screw and a cooperating nut and a spring mounted on the screw between the nut and a stop so that the screw may be tensioned by turning of the nut, said screw being connected to an arm mounted on said one assembly by a nut which is penetrated by said screw, said screw being turned in relation to the nut in order to set the starting position of the centering means.
2. Apparatus as in claim 1 wherein said spring device can be adjusted not only in respect to the tension of the spring but also for adjusting the normal spacing of the centering means.
Description:
The invention relates to a device for centering of timber blocks and the like during feeding-in to sawing machines in which swingably arranged centering means, to work on opposite sides of the block, are coupled so that from a starting position (normal position) they move outwards from each other or inwards towards each other an equal distance. The linking up of the centering means is achieved by means of one or more chains, bands or the like which run in opposite directions over chain wheels or the like attached to the centering means, and a spring device, which determines the normal position, is attached to at least one of the centering means.
The purpose of the invention is to achieve a simple and operationally dependable construction of a device of said type which also makes simple adjustment of the normal position for the centering means possible.
The invention is mainly characterized in that the spring device consists of a screw and a nut working in conjunction with it as well as a spring disposed on the screw between the nut and a stop, said spring being tensioned more or less by turning the nut, and that the screw is connected to an arm mounted on the centering means via a nut which is penetrated by the screw, the starting position of the centering means thus being adjusted by turning of the screw in relation to the nut.
In this way centering of the block is achieved in relation to a given point on the sawing machine into which the centered block is to be fed for sawing into boards or the like. A precision centering device is of importance for the quality of the sawn lumber, and a centering device according to the invention has been shown to fulfill all the requirements since it holds the block so exactly centered in relation to the sawing machine that the control lines of the sawing machine and the block coincide along the whole length of the block. In other words the block will be cut exactly along the pith line of the log or trunk if the centering device is set for this purpose. It has been shown that this means an increase in the average length of the sawn product thereby improving the volume yield at the same time as the amount of wood, which normally goes to a chipper, is reduced accordingly.
An example of the application of the invention is described with reference to the enclosed drawing. FIG. 1 shows a plane view of an automatic aligning device and a frame with a block centering device according to an embodiment of the invention. The rest of the figures show the block centering device in larger scale, specifically, FIG. 2 in a horizontal projection and FIG. 3 in a vertical projection, partially in section. FIG. 4 shows on a still larger scale the spring device partially in axial section.
In the schematic plane view according to FIG. 1, 1 designates a trunk or a block which comes to the device after it has been trimmed on two opposite sides in a cant gang saw. The block comes in on a longitudinal conveyor belt 2 and is first stopped by a stop 3 at an appropriate side position directly in front of an automatic aligning device 4 onto whose carrying rollers 5 and feeder rollers 6 the block is moved laterally on a lateral transport device 7. The block 1 is shown on the one hand in that position where it has been stopped by the stop 3, and on the other hand in a position 1', where it is in a block centering device 8 and has partially been fed through a frame 9. The direction of feed is indicated by the arrows 10. 11 designates the middle line of the sawing machine with which the center line of the block is to be made to coincide by the operation of the centering device 8.
The centering means consist essentially of a pair of cranks with crank arms 15a, 15b and vertical axles 16a, 16b and taps 17a, 17b parallel to them which function as bearings for the rollers 18a, 18b designed to engage with the block which is fed in between them. The axels 16a, 16b are carried in the bearing bracket 12 by means of bearing sleeves 19a, 19b and on their outer ends they bear chain wheels 20a, 20b wedged securely on the same. In the embodiment shown in FIG. 3 on each axle there are two chain wheels which are mutually connected by means of a hub shell 21a, 21b but in principle it could be sufficient with one wheel on each axle, especially if the chain can be bent laterally or is replaced by a flexible band. A chain 22 runs over both the wheels 20a, 20b and in the same manner a chain 22' runs over both of the other chain wheels. The chains 22, 22' have their ends fastened on the wheels. The chains run in opposite directions over the chain wheels so that they run on the upper side of the chain wheel 20a when they come from the underside of the chain wheel 20b. If the movement is transferred by means of a cable instead of a chain, the cable can be endless. An adjustable cable or chain lock 23 allows for control of the tension. The parts of the chain or cable, which are between the wheels, cross each other as is shown in FIG. 2.
With one of the chain wheels or corresponding crank arm 20b or 15b, an arm 24 is securely united to which a spring device is attached. Said spring device is designated by 25 in FIG. 2 and is shown in detail in FIG. 4.
The spring device consists of a scrrew 26 and a nut 27 working in conjunction with it as well as a spring mounted on the screw between the nut and a stop 28 and threaded on a tube 28' on the screw. Said spring can be given more or less tension by turning the nut 27.
The arm 24, which in the embodiment shown is fork-shaped at the bottom or is doubled, carries between the tines of the fork a nut 31 which, by means of taps transverse to the screw, is journalled in the tines of the arms 24. The screw 26 goes through and works in conjunction with the nut 31. The screw 26 can be rotated by means of a hand crank 32 or the like mounted at its end. The tube 28' surrounding the screw is displaceably journalled in the wall of the bearing bracket 12 by means of a ball-and-socket joint 33, 34. There is a stop ring 35 for a damper on the ball, e.g., in the form of a rubber bushing 36 which sits on a sleeve 37 concentric with the screw and enclosing the same. The hand crank 32 is also attached to the sleeve 37.
The operation of the device proceeds as follows:
In the starting position the crank arms 15a, 15b of the centering means are parallel and have been set in this position by adjustment by means of the crank 32 and the screw 26. In doing this setting the tension in the spring is not changed since the stop 28 for the spring 29 is rotatable against the ball 33 and the nut 27 is brought along when the screw is turned. The centering device 8 is adjusted on the guides 14 so that its middle lies right in front of the middle point of the sawing machine 9. The rollers 18a and 18b are spaced so that the block 1' will be in contact with both of the rollers when it is advanced between them by the feeder rollers 6.
If, for example, a bulge on the left side of the block in FIGS. 1-2 presses the roller 18a outwards, e.g., to the position 18a' indicated with the dash-and-dot lines in FIG. 2, the axle 16a will turn and bring with it the chain wheel 20a. This movement is transferred by means of the chains 22, 22' to the chain wheel 20b which turns the axle 16b in the opposite direction to the axle 16a, the arm 15b thereby swinging out the roller 18b, just as much as the roller 18a was previously swung out, to the position 18b' indicated with dash-and-dot lines in FIG. 2. The block is then centered in relation to the bulge so that its center will lie on the middle line of the centering device. This swinging out is done against the force of the spring since the arm 24 presses the screw 26 to the left in FIG. 2 so that the nut 27 presses the spring 29 against the stop 28. Because of the spring force the rollers 18a, 18b will always be held in contact with the block, if it has those dimensions for which the centering device is adjusted. If the rollers 18a, 18b swing quickly back from a swung-out position, so that the screw 26 connected to the arm 24 is thrown to the right in FIG. 2, the shock is absorbed by the damper 36, 35.
If one of the rollers, 18a for example, due to an inward bend in the block 1' is swung to the right in FIG. 2, e.g., to the position indicated with the dash-and-dot lines 18a", the roller 18b is swung via the chain transmission inwards to the left in FIG. 2 just as much, i.e., to the position designated with the dash-and-dot lines 18b", so that centering is achieved in this case also. The spring 29, which is assumed to be pretensed the required amount by means of the nut 27, is then allowed to expand by the nut 27 being drawn to the right in FIG. 4 by the screw, the tube 28' following with it and sliding on the ball 33. The stop 28 stays in contact with the ball 33.
The purpose of the invention is to achieve a simple and operationally dependable construction of a device of said type which also makes simple adjustment of the normal position for the centering means possible.
The invention is mainly characterized in that the spring device consists of a screw and a nut working in conjunction with it as well as a spring disposed on the screw between the nut and a stop, said spring being tensioned more or less by turning the nut, and that the screw is connected to an arm mounted on the centering means via a nut which is penetrated by the screw, the starting position of the centering means thus being adjusted by turning of the screw in relation to the nut.
In this way centering of the block is achieved in relation to a given point on the sawing machine into which the centered block is to be fed for sawing into boards or the like. A precision centering device is of importance for the quality of the sawn lumber, and a centering device according to the invention has been shown to fulfill all the requirements since it holds the block so exactly centered in relation to the sawing machine that the control lines of the sawing machine and the block coincide along the whole length of the block. In other words the block will be cut exactly along the pith line of the log or trunk if the centering device is set for this purpose. It has been shown that this means an increase in the average length of the sawn product thereby improving the volume yield at the same time as the amount of wood, which normally goes to a chipper, is reduced accordingly.
An example of the application of the invention is described with reference to the enclosed drawing. FIG. 1 shows a plane view of an automatic aligning device and a frame with a block centering device according to an embodiment of the invention. The rest of the figures show the block centering device in larger scale, specifically, FIG. 2 in a horizontal projection and FIG. 3 in a vertical projection, partially in section. FIG. 4 shows on a still larger scale the spring device partially in axial section.
In the schematic plane view according to FIG. 1, 1 designates a trunk or a block which comes to the device after it has been trimmed on two opposite sides in a cant gang saw. The block comes in on a longitudinal conveyor belt 2 and is first stopped by a stop 3 at an appropriate side position directly in front of an automatic aligning device 4 onto whose carrying rollers 5 and feeder rollers 6 the block is moved laterally on a lateral transport device 7. The block 1 is shown on the one hand in that position where it has been stopped by the stop 3, and on the other hand in a position 1', where it is in a block centering device 8 and has partially been fed through a frame 9. The direction of feed is indicated by the arrows 10. 11 designates the middle line of the sawing machine with which the center line of the block is to be made to coincide by the operation of the centering device 8.
The centering means consist essentially of a pair of cranks with crank arms 15a, 15b and vertical axles 16a, 16b and taps 17a, 17b parallel to them which function as bearings for the rollers 18a, 18b designed to engage with the block which is fed in between them. The axels 16a, 16b are carried in the bearing bracket 12 by means of bearing sleeves 19a, 19b and on their outer ends they bear chain wheels 20a, 20b wedged securely on the same. In the embodiment shown in FIG. 3 on each axle there are two chain wheels which are mutually connected by means of a hub shell 21a, 21b but in principle it could be sufficient with one wheel on each axle, especially if the chain can be bent laterally or is replaced by a flexible band. A chain 22 runs over both the wheels 20a, 20b and in the same manner a chain 22' runs over both of the other chain wheels. The chains 22, 22' have their ends fastened on the wheels. The chains run in opposite directions over the chain wheels so that they run on the upper side of the chain wheel 20a when they come from the underside of the chain wheel 20b. If the movement is transferred by means of a cable instead of a chain, the cable can be endless. An adjustable cable or chain lock 23 allows for control of the tension. The parts of the chain or cable, which are between the wheels, cross each other as is shown in FIG. 2.
With one of the chain wheels or corresponding crank arm 20b or 15b, an arm 24 is securely united to which a spring device is attached. Said spring device is designated by 25 in FIG. 2 and is shown in detail in FIG. 4.
The spring device consists of a scrrew 26 and a nut 27 working in conjunction with it as well as a spring mounted on the screw between the nut and a stop 28 and threaded on a tube 28' on the screw. Said spring can be given more or less tension by turning the nut 27.
The arm 24, which in the embodiment shown is fork-shaped at the bottom or is doubled, carries between the tines of the fork a nut 31 which, by means of taps transverse to the screw, is journalled in the tines of the arms 24. The screw 26 goes through and works in conjunction with the nut 31. The screw 26 can be rotated by means of a hand crank 32 or the like mounted at its end. The tube 28' surrounding the screw is displaceably journalled in the wall of the bearing bracket 12 by means of a ball-and-socket joint 33, 34. There is a stop ring 35 for a damper on the ball, e.g., in the form of a rubber bushing 36 which sits on a sleeve 37 concentric with the screw and enclosing the same. The hand crank 32 is also attached to the sleeve 37.
The operation of the device proceeds as follows:
In the starting position the crank arms 15a, 15b of the centering means are parallel and have been set in this position by adjustment by means of the crank 32 and the screw 26. In doing this setting the tension in the spring is not changed since the stop 28 for the spring 29 is rotatable against the ball 33 and the nut 27 is brought along when the screw is turned. The centering device 8 is adjusted on the guides 14 so that its middle lies right in front of the middle point of the sawing machine 9. The rollers 18a and 18b are spaced so that the block 1' will be in contact with both of the rollers when it is advanced between them by the feeder rollers 6.
If, for example, a bulge on the left side of the block in FIGS. 1-2 presses the roller 18a outwards, e.g., to the position 18a' indicated with the dash-and-dot lines in FIG. 2, the axle 16a will turn and bring with it the chain wheel 20a. This movement is transferred by means of the chains 22, 22' to the chain wheel 20b which turns the axle 16b in the opposite direction to the axle 16a, the arm 15b thereby swinging out the roller 18b, just as much as the roller 18a was previously swung out, to the position 18b' indicated with dash-and-dot lines in FIG. 2. The block is then centered in relation to the bulge so that its center will lie on the middle line of the centering device. This swinging out is done against the force of the spring since the arm 24 presses the screw 26 to the left in FIG. 2 so that the nut 27 presses the spring 29 against the stop 28. Because of the spring force the rollers 18a, 18b will always be held in contact with the block, if it has those dimensions for which the centering device is adjusted. If the rollers 18a, 18b swing quickly back from a swung-out position, so that the screw 26 connected to the arm 24 is thrown to the right in FIG. 2, the shock is absorbed by the damper 36, 35.
If one of the rollers, 18a for example, due to an inward bend in the block 1' is swung to the right in FIG. 2, e.g., to the position indicated with the dash-and-dot lines 18a", the roller 18b is swung via the chain transmission inwards to the left in FIG. 2 just as much, i.e., to the position designated with the dash-and-dot lines 18b", so that centering is achieved in this case also. The spring 29, which is assumed to be pretensed the required amount by means of the nut 27, is then allowed to expand by the nut 27 being drawn to the right in FIG. 4 by the screw, the tube 28' following with it and sliding on the ball 33. The stop 28 stays in contact with the ball 33.