US3733067A - Log rotating and feeding device with continuous supporting device - Google Patents

Abstract

A device for feeding logs through the saws of a sawmill or through other wood-processing machines includes a pair of logholding arms supported on overhead carriages movable along a track extending parallel to the feeding line of the logs through the saws. A lower portion of each arm has a log end-gripping device that restrains the log against rotation and lateral movement with respect to the arm but permits limited vertical movement of the log while clamped between the two arms. Each such gripping device includes a plate provided with a spiked or other gripping surface. The plates are resiliently mounted on their arms in upwardly biased positions but move downwardly on the arms under the weight of a log to lower a gripped log onto a subjacent elongate support which supports the log as it is fed by the arms through the saws. In one embodiment the subjacent support is driven so as to help feed as well as support the log.

Description

[ 51 May 15, 1973 [54] LOG ROTATING AND FEEDING DEVICE WITH CONTINUOUS SUPPORTING DEVICE [75] Inventor: Bo Ingemar Ackerteldt,

Ascona, Switzerland [73] Assignee: U. S. Natural Resources, Inc., Portland, Oreg.

[22] Filed: Nov. 24, 1971 [21] Appl. No.: 201,932

Primary Examiner-Donald R. Schran A ttorney- Stephen W. Blore et al.

[57] ABSTRACT A device for feeding logs through the saws of a sawmill or through other wood-processing machines includes a pair of log-holding arms supported on overhead carriages movable along a track extending parallel to the feeding line of the logs through the saws. A lower portion of each arm has a log end-gripping device that restrains the log against rotation and lateral movement with respect to the arm but permits V U.S. CI...V....I limited vertical movement of the log while clamped Int. Cl. betwcen the two arms Each such device inof Search A, R, A, cludes a plate provided a or other 143/105 105 Bi 52 52 125 125 R surface. The plates are resiliently mounted on their v arms in upwardly biased positions but move [56] References C'ted downwardly on the arms under the weight of a log to UNITED STATES PATENTS lower a gripped log onto a subjacent elongate support which supports the log as it is fed by the arms through 2,673,581 3/1954 Dornath 6! a1 5 A X the saws. In one embodiment the subjacent support is 3,503,428 3/1970 Ackerfeldt ..l43/ 105 R X driven so as to help feed as we as Support the I 13 Claims, 4 Drawing Figures 1 l w a m 1 75 m i -1: *c: E :1 so q l: 20 4 I /l n 7 at? BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for feeding logs or blocks through one or several saws or other logprocessing machines.

2. Description of Prior Art This log-feeding device is of the general type described in, for instance, US. Pat. No. 3,503,428 and comprises consequently at least two substantially vertical dependent log-holding arms, which are supported by and movable along a trackway extending above the saw or saws parallel to the desired feeding line for the logs through the saw from its input side to its output side. The arms are adapted to have their lowermost ends act against the fore and rear end surfaces, respectively, of a log and in this way hold the log between them while feeding the log along the feeding line through the saw. In the log-feeding device of this type, illustrated by way of example in FIGS. 1-4 of U.S. Pat No. 3,503,428, the two log-holding arms are driven to and fro along the trackway extending above the saw. Such log-holding arms are movable between a lowered working position, in which the arms can hold a log in the feeding line with their lowermost ends, and a raised inactive positionfin which the arms can be returned along the trackway from the output side of the saw to;

the input'side thereof without impeding a log located in the feeding line.

In the log-feeding device of a similar'type, illustrated by way of example in FIGS. 5-12 of US. Pat. No. 3,503,428, on the contrary, the trackway for the logholding arms, which preferably are more than two in this log-feeding device, is formed as a closed circuit for the log-holding arms, along which the log-holding arms are driven always in the same direction.

This is the case also in another prior log-feeding device in which, however, the logs are fed through the saw in an uninterrupted succession with only one logholding arm between each pair of immediately successive logs so that each arm holds the rear end of the preceding log as well as the fore end of the succeeding log.

Also other log-feeding devices of the general type defined in the foregoing are possible and have been suggested in the prior art. Thus, for instance, contrary to the log-feeding devices disclosed in the patent men tioned in the foregoing, where the log-holding arms are mounted on separate carriages, the two log-holding arms may instead be mounted on a common carriage which is supported by and movable along the trackway.

In all prior log-feeding devices of the general type described in the foregoing, however, it is implied that the logs held between the log-holding arms while being fed through the saw or saws respectively from the input side to the output side are supported entirely by the log-holding arms andc'onsequently are hanging in these with their entire weight. For very heavy logs or in saws or other log-processing machines which exert large downwardly directed forces upon the log while processing it, large stresses are exerted upon the loggripping portions of the arms, upon the log-holding arms themselves and upon the trackway supporting the log-holding arms. It can be very difficult and expensive to give the log-holding arms and their log-gripping portions sufficient dimensions for these stresses and forces,

as the arms and their gripping members must be able to pass through the processing machines, for instance between the two saw blades in a double band saw.

SUMMARY OF THE INVENTION The object of the present invention is, therefore, to provide a log-feeding device of the general type mentioned in the foregoing, which can be used also for very heavy logs and with processing machines which exert very considerable downwardly directed forces upon the logs being processed.

According to the present invention, this object is achieved by means of a log-feeding device of the general type described in the foregoing and designed in accordance with the enclosed claims.

BRIEF DESCRIPTION OF DRAWINGS vice according to the invention taken along the line III- lll in FIG. 2; and

FIG. 4 is a section through the lowermost end of a log-holding arm taken along the line lV--IV in FIG. 3.

DETAILED DESCRIPTION The drawing shows schematically a double band saw 7 having two saw blades 25, 26. The feeding direction for the logs through the saw 7 during the sawing is indicated with an arrow in FIG. 1. For feeding logs through the saw 7, a log-feeding device is provided, which is to a large extent of the same type as the log-feeding device illustrated in FIGS. l-4 of US. Pat. No. 3,503,428 and which is described more in detail therein.

Thus, the log-feeding device comprises a fore logholding arm 8 and a rear log-holding arm 9, which are mounted on two separate carriages l4 and 15 respectively. The carriages are supported by and movable along a trackway 13, which extends above the saw 7 parallel to the desired feeding line for the logs through the saw from its input side to its output side. Each logholding arm 8, 9 is pivoted in its associated carriage 14, 15, respectively, and can be swung with a schematically illustrated hydraulic cylinder 8a, 9a, respectively, between a vertical working position shown in solid lines and a horizontal inactive position shown in dotted lines.

For driving the carriages 14, 15 with their associated log-holding arms 8, 9 along the trackway 13, an endless, preferably continuously driven chain 10 is provided. The carriages 14, 15 are provided with special coupling means for selectively connecting the carriages to the drive chain 10 in the manner described more in For receiving and adjusting a log 1 to be sawn in the saw 7, a number of vertically displaceable roller stands 3, 4, 5 are provided at the input side of the saw. Two or several of these roller stands can be raised for receiving and supporting a log 1. The log is delivered to the input side of the saw 7 in some suitable manner not illustrated in detail in the drawing. As most readily seen in FIG. 2, each of these roller stands 3, 4, 5 is provided with a number of rotatable rollers or wheels 6, which support the log 1 and on which the log can be rotated about its longitudinal axis to a preferred position for the sawing of the log in the saw 7.

In contrast to the prior art log-feeding device described in U.S. Pat. No. 3,503,428, each log-holding arm 8, 9 in the log-feeding device according to the present invention is, as most readily seen in FIGS. 3 and 4, at its lowermost end provided with a number of spikes 16, which are adapted to be pressed into the end surface of the log 1. These spikes are attached to a plate 17, which is mounted in a guide groove 18 in the log-holding arm so as to be movable in a vertical direction relative to the log-holding arm but guided laterally relative thereto. The plate 17 with the spikes 16 is urged by a spring 19 in a direction upwards to its uppermost position relative to the log-holding arm.

Further, an endless feed chain 20 is provided, which extends parallel to and underneath the feeding line for the logs through the saw 7 from its input side to its output side. Preferably this chain 20 is driven by driving means not illustrated in detail in the drawing with the same speed as the drive chain 10 for the arm carriages l4, 15. The chain 20 runs in a groove in a stationary guide rail 24 so that the upper part of the chain 20 is supported from below over its entire length. The chain 20 is preferably also provided with spikes 21.

The log-feeding device described operates in the following manner: When the log 1 supported on the raised roller stands 3 and 5 has been rotated about its longitudinal direction to the desired position for the sawing of the log, the two log-holding arms 8 and 9 are lowered by means of their associated hydraulic cylinders 8a and 9a respectively to their vertical working positions, in which the log-holding arms are automatically locked. The carriage 14 of the fore log-holding arm 8 is in this stage held by the retainer pawl 11 in the position illustrated in FIG. 1. Further, it is assumed that the log 1 is in such a position that its fore end surface is situated immediately behind the lowered fore log-holding arm 8.

The carriage 15 of the rear log-holding arm 9 is then connected to the drive chain 10, causing the'rear logholding arm to move forward and hit the rear end surface of the log 1 with the spikes l6 and thereby start to push the log forward toward the fore log-holding arm 8. This is possible because the roller stands 3 and 5 supporting the log 1 are movable parallel to the feeding line.

When the fore end surface of log 1 hits the spikes on the fore log-holding arm, such arm is displaced together with its carriage 14 in a direction forwardly along trackway 13. At the same time, spring member 1 1a of the retainer pawl 11 is tensioned. Consequently the clamping force upon log 1 between the log-holding arms 8 and 9 is increased, and the spikes 16 on the logholding arms are pressed into the fore and rear end surfaces of the log.

Eventually, when the desired clamping force has been achieved, the spring-biased retainer pawl 11 reaches its release cam 12, which raises the retainer pawl 11 so that the carriage 14 of the fore log-holding arm 8 is released. At the same instant, the carriage 14 is automatically connected to the drive chain 10 in the manner described more in detail in U.S. Pat. No. 3,503,428. Consequently, log 1 is moved forwardly toward saw 7 clamped between the two log-holding arms 8 and 9, which have their spikes 16 pressed into the end surfaces of the log.

As soon as log 1 has been clamped between the arms 8 and 9 in the manner described above, roller stands 3 and 5 previously. supporting the log 1 are automatically lowered to a position underneath chain 20. Because spikes 16 of the log-holding arms 8 and 9 are mounted on plates 17, which are movable in a vertical direction relative to the log-holding arms, log 1 sinks down onto the chain 20 when roller stands 3, 5 are lowered. Consequently chain 20 supports log 1, whereby the logholding arms 8, 9 and their carriages 14, 15 and trackway 13 are relieved of the full weight of the log 1 as well as any downward forces exerted upon the log 1 during the sawing of the log in the saw 7.

It is appreciated that during the entire feeding of log 1 through saw 7 from its input side to its output side, chain 20 supports the log. As the chain 20 is driven and provided with the spikes 21, the chain 20 also assists in the feeding of the log 1 through the saw 7. Thus the forces and the stresses on the log-holding arms 8 and 9, their associated carriages 14 and 15 and the drive chain 10 are further reduced.

Nevertheless, during the feeding operation, log 1 is still clamped between the two log-holding arms 8 and 9, which prevent, by means of their spikes 16 pressed into the end surfaces of the log, any lateral displacement or rotation of the log relative to the log-holding arms. In this way the log-holding arms provide a very accurate guiding of the log and thereby a very accurate cutting of the log in the saw.

In order to improve the lateral guiding of the logholding arms 8 and 9 and thus also of the log 1, the lowermost ends of the log-holding arms 8 and 9 may preferably be provided with flanges 22 and 23. These flanges are located on opposite sides of the stationary guide rail 24 for the chain 20 so as to be guided by this guide rail, as most readily seen in FIG. 2.

Numerous other embodiments of a log-feeding device according to the invention are possible within the frame of the invention. Thus, for instance, chain 20 may be replaced with a stationary skid rail or a similar device, which preferably may be provided with one or several longitudinally extending edges for guiding the log 1. In such an embodiment of the invention, which is especially suitable for lighter logs, the feeding of the logs through the saw is carried out only by means of the log-holding arms.

Also the gripping members of the log-holding arms cooperating with the end surfaces of the logs can be of another design than illustrated in FIGS..3 and 4. Instead of spikes 16, the log-holding arms may thus for instance be provided with elongated vertical edges. These edges are pressed into the end surface of the log, and thereby effectively prevent any lateral displacement or rotation of the log relative to the log-holding arm while permitting a vertical displacement of the log relative to the log-holding arm.

Although in the foregoing the invention has been described and illustrated as used in a log-feeding device of the type shown in FIGS. 1-4 of US. Pat. No. 3,503,428, it is appreciated that the invention can be used with the same advantages also in a log-feeding device, for instance, of the type shown in FIGS. 5-12 of said patent or in any other log-feeding device of the general type defined in the introduction of this specification.

Having illustrated and described a preferred embodiment of my invention and having also suggested several possible alternative embodiments, it should be apparent to those skilled in the art that my invention permits of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the following claims.

I claim:

1. A device for feeding logs through at least one saw or some other log-processing machine, comprising:

at least two dependent log-holding arms supported by and movable along a trackway extending above and parallel to the desired feeding line for the logs through the saw from its input side to its output side,

said arms being adapted to act with lower portions thereof against the fore end surface and the rear end surface of a log and to hold the log between them while feeding the log along said feeding line through the saw from its input side to its output side,

each said log-holding arm including gripping means for engaging the end surface of a log in a manner so as to restrain the log against lateral displacement and rotation relative to the log-holding arm,

and mounting means mounting said gripping means on said arms for limited vertical movement on said arms, said mounting means including biasing means urging said gripping means to an upwardly biased position on said arms, said biasing means being overcome by the weight of the log engaged by said gripping means to lower said gripping means and said log on said arms.

2. A device as claimed in claim 1 wherein elongated supporting means is provided to extend parallel to said feeding line through the saw from its input side to its output side and at a level below said gripping means and a log when initially engaged by said gripping means such that the log when engaged by said gripping means and unsupported from below will be-lowered onto and supported by said support means as it is held between said log-holding arms and fed through the saw from its input side to its output side.

gated support means comprises a stationary skid rail.

4, A device as claimed in claim 3 wherein said skid rail is provided with one or several longitudinally extending edges for laterally guiding of the logs.

5. A device as claimed in claim 2 wherein the lowermost ends of said log-holding arms and said elongated support means cooperate in a manner so as to restrain lateral deflection of the lower ends of said log-holding arms as they feed a log held therebetween along the feed line and through the saw from its input side to its output side.

6. A device as claimed in claim 2 wherein said elongated support means comprises a conveyor driven substantially at the same speed as said'log-holding arms.

7. A device as claimed in claim 6 wherein said conveyor comprises an endless chain provided with logengaging means at spaced intervals therealong.

8. A device as claimed in claim 1 wherein said gripping means comprises spikes adapted to be pressed into the end surface of a log, the spikes being attached to a plate means mounted on said log-holding arm so as to be substantially unmovable relative thereto in a lateral direction but to have a limited movability in a vertical direction relative to the arm.

9. A device as claimed in claim 8 wherein said plate means is urged in an upward direction by a resilient I means and movable in a downward direction against said resilient means by the weight of a log engaged by said spikes.

10. A device as claimed in claim 1 wherein said gripping means at the lowermost end of each log-holding arm includes one or several elongated vertical edges adapted to be pressed into the end surface of a log and attached to a plate means mounted on said log-holding arm so as to be substantially unmovable relative thereto in a lateral direction but to have a limited movability in a vertical direction relative to the arm.

11. A device as claimed in claim 2 including vertically movable support means positioned along said feeding line at the input side of the saw, said vertically movable support means being vertically displaceable between a lower position below the support surface of said elongated support means and a raised position above said support surface of said elongated support means for temporarily supporting a log while the log is being gripped between the log-holding arms.

12. A device as claimed in claim 11 wherein said vertically movable support means includes roller means for supporting the log and permitting rotation of the log about the longitudinal axis of the log.

13. A device as claimed in claim 1 1 wherein said vertically movable support means includes several support members spaced along said feeding line, each being vertically displaceable.

Claims (13)

1. A device for feeding logs through at least one saw or some other log-processing machine, comprising: at least two dependent log-holding Arms supported by and movable along a trackway extending above and parallel to the desired feeding line for the logs through the saw from its input side to its output side, said arms being adapted to act with lower portions thereof against the fore end surface and the rear end surface of a log and to hold the log between them while feeding the log along said feeding line through the saw from its input side to its output side, each said log-holding arm including gripping means for engaging the end surface of a log in a manner so as to restrain the log against lateral displacement and rotation relative to the logholding arm, and mounting means mounting said gripping means on said arms for limited vertical movement on said arms, said mounting means including biasing means urging said gripping means to an upwardly biased position on said arms, said biasing means being overcome by the weight of the log engaged by said gripping means to lower said gripping means and said log on said arms.

2. A device as claimed in claim 1 wherein elongated supporting means is provided to extend parallel to said feeding line through the saw from its input side to its output side and at a level below said gripping means and a log when initially engaged by said gripping means such that the log when engaged by said gripping means and unsupported from below will be lowered onto and supported by said support means as it is held between said log-holding arms and fed through the saw from its input side to its output side.

3. A device as claimed in claim 2 wherein said elongated support means comprises a stationary skid rail.

4. A device as claimed in claim 3 wherein said skid rail is provided with one or several longitudinally extending edges for laterally guiding of the logs.

5. A device as claimed in claim 2 wherein the lowermost ends of said log-holding arms and said elongated support means cooperate in a manner so as to restrain lateral deflection of the lower ends of said log-holding arms as they feed a log held therebetween along the feed line and through the saw from its input side to its output side.

6. A device as claimed in claim 2 wherein said elongated support means comprises a conveyor driven substantially at the same speed as said log-holding arms.

7. A device as claimed in claim 6 wherein said conveyor comprises an endless chain provided with log-engaging means at spaced intervals therealong.

8. A device as claimed in claim 1 wherein said gripping means comprises spikes adapted to be pressed into the end surface of a log, the spikes being attached to a plate means mounted on said log-holding arm so as to be substantially unmovable relative thereto in a lateral direction but to have a limited movability in a vertical direction relative to the arm.

9. A device as claimed in claim 8 wherein said plate means is urged in an upward direction by a resilient means and movable in a downward direction against said resilient means by the weight of a log engaged by said spikes.

10. A device as claimed in claim 1 wherein said gripping means at the lowermost end of each log-holding arm includes one or several elongated vertical edges adapted to be pressed into the end surface of a log and attached to a plate means mounted on said log-holding arm so as to be substantially unmovable relative thereto in a lateral direction but to have a limited movability in a vertical direction relative to the arm.

11. A device as claimed in claim 2 including vertically movable support means positioned along said feeding line at the input side of the saw, said vertically movable support means being vertically displaceable between a lower position below the support surface of said elongated support means and a raised position above said support surface of said elongated support means for temporarily supporting a log while the log is being gripped between the log-holding arms.

12. A device as claimed in claim 11 wherein said vertically movable support means includes roller means for Supporting the log and permitting rotation of the log about the longitudinal axis of the log.

13. A device as claimed in claim 11 wherein said vertically movable support means includes several support members spaced along said feeding line, each being vertically displaceable.

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