CA1279559C - Frame saw and a method for its use - Google Patents

Frame saw and a method for its use

Info

Publication number
CA1279559C
CA1279559C CA000536483A CA536483A CA1279559C CA 1279559 C CA1279559 C CA 1279559C CA 000536483 A CA000536483 A CA 000536483A CA 536483 A CA536483 A CA 536483A CA 1279559 C CA1279559 C CA 1279559C
Authority
CA
Canada
Prior art keywords
blade
eccentric
sawing
workpiece
eccentric device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
CA000536483A
Other languages
French (fr)
Inventor
Ove C. Lagerquist
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DOUBLE O SAW TECHNOLOGY Ltd
Original Assignee
DOUBLE O SAW TECHNOLOGY Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DOUBLE O SAW TECHNOLOGY Ltd filed Critical DOUBLE O SAW TECHNOLOGY Ltd
Application granted granted Critical
Publication of CA1279559C publication Critical patent/CA1279559C/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B27WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27BSAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
    • B27B3/00Gang saw mills; Other sawing machines with reciprocating saw blades, specially designed for length sawing of trunks
    • B27B3/02Gang saw mills; Other sawing machines with reciprocating saw blades, specially designed for length sawing of trunks with vertically-reciprocating saw frame
    • B27B3/12Mechanisms for producing the reciprocating movement of the saw frame; Arrangements for damping vibration; Arrangements for counter-balancing

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Sawing (AREA)

Abstract

ABSTRACT

A method for sawing workpieces in frame saws, in which at least one saw blade mounted in an attachment device, such as a frame or the like, is caused to execute a substantially reciprocating movement. Sawing of a workpiece advanced towards the blade is effected during at least a part of the blade movement. The method is particularly characterized in that blade movement is effected by means of two eccentric devices each of which is journalled to and co-acts with a respective one of the two end parts of the attachment device. At least one blade is, intended to extend substantially between the end parts. Each end part is caused to execute a rotary movement about the rotational axis of the eccentric device located at this end part. The invention also relates to an arrangement for carrying out the method.

Description

5 5~

A METHOD FOR_SAWING WORKPIECES IN FRAME SAWS, AND AN
ARRANGEMENT FOR CARRYING OUT THE MET~OD.

The present invention relates to a method for sawing workpieces in a frame saw and to an arrangement for carrying out the method.

The saw blades of a frame saw are normally reciprocated longitudinally of the blades when executing a sawing action. This blade movement is effected through repeated acceleration and retardation of the blades, which results in undesirable vibrations and stresses.
Furthermore, when the workpiece is made of wood, the wood is liable to split or tear on at least one side of the workpiece.

The present invention relates to a method and to an arrangement in which, according to one embodiment, the workpiece is sawn in both directions of blade move-ment, which greatly improves the production rate and also avoids splitting or cracking of the workpiece. A rotary movement is used, which greatly reduces the vibrations and stresses of prior art methods.

Thus, the invention relates to a method of sawing workpieces in frame saws in which at least one saw blade attached to a frame or the like is caused to exe-cute a substantially reciprocatory movement, whereby sawing of a workpiece fed towards the blade can be effected during at least a part of said blade movement.

The method is particularly characterized in that said blade movement is effected by means of two eccentric devices each of which is journalled to and co-acts with a respective one of two end parts of the attachment device, one or more blades being intended to extend essentially between said end parts and each end part being caused to carry out a rotary movement about the rotary axis of the eccentric device located at said end part.

The invention also relates to an arrangement in frame saws of the kind which comprise at least one saw blade which is attached to an attachment device, such as a frame or corresponding device. The saw reciprocates and sawing of a workpiece fed towards the blade is effected during at least a part of the reciprocation.

The arrangement is particularly characterized by two eccentric devices which are operative in effecting reciprocating movement of the blade and each of which is journalled to and co-acts with a respective one of the two end parts of the attachment device, wherein at least 1~79~S9 one saw blade is intended to extend essentially between said end parts, and wherein each end part is arranged to execute a rotary movement around the rotary axis of the eccentric device located at said end part.

The invention is illustrated, by way of example, in the accompanying drawings, in which:

Figure 1 is a schematic side view of a first embodiment of the invention, seen transversely to the direction in which the workpiece to be sawn is advanced;
Figure 2 illustrates the embodiment of Figure 1 from the left of said Figure;
Figure 3 is a view on the line A-A in Figure 2;
Figure 4 is a view on the line B-B in Figure 2;
Figure 5 is a schematic side view of a second embodiment of an arrangement according to the invention, seen in the same direction as the arrangement illustrated in Figure 1;
Figure 6 illustrates schematically two moments of a sawing action during which sawing of a workpiece is efffected in both directions of reciprocating blade travel;
Figure 7 illustrates schematically a displace-ably arranged, journalled attachment; and Figure 8 illustrates schematically a third embodiment of the invention, seen in the same direction as Figure 1.

~795~3 In Figure 1 a workpiece 1 is intended to be advanced horizontally in the direction of the arrow 2 and to be sawn by means of at least one saw blade 3, which is attached to an attachment device 4, such as a frame 4 or the like, and which is intended to execute a recipro-cating movement, as indicated by the arrows 5.

This blade movement is effected by two eccentric devices 6, each of which is journalled to and co-acts with a respective one of two end parts 7 of the attachment device 4. Each end part 7 can rotate about the rotary axis 8 of the eccentric device located at a respective end part 7. The end parts 7 referred to here need not be the extremities of the frame or like attach-ment device, as seen in the direction of the long axis of the blade (as shown in Figure 1) but may be parts which are located at a given distance from a centre point such as the central region 3', as illustrated in Figure 6.
With regard to the location of the journalled connection, however, the Figure 1 embodiment is preferred, since a more pronounced, reciprocatory blade movement can be obtained with this embodiment.

The illustrated, simplified embodiment includes an eccentric device 6 which comprises two halves, one to the right and one to the left of Figure 2. Each ~ '~79S59 eccentric half comprises essentially an oscillating disc 10 which is journalled for rotation on a shaft 9. An arm 11 extends substantially radially from disc 10 and the attachment device is connected by means of a journal pin 12 or the like.

According to one preferred embodiment the radial distance a (Figure 1) between the rotational axis 8 of the eccentric device and the rotational centre 13 of the pivotal connection between the eccentric device and the end part 7 is approximately the same for both eccentric devices 6.

Alternatively, the distance a may differ noticeably betwen the two eccentric devices. In this case the rotational centre 13 of the pivotal connection may be arranged so that at least one eccentric device will be displaced radially as it rotates. This arrange-ment is illustrated schematically in Figure 7, which shows a groove 14 in which the journal pin 12 or like device can be moved.

Preferably the radial distance a can be changed to enable the characteristics of the sawing process to be changed. To achieve this, attachment points 15 for the attachment means on the arm 11 are provided, as illustrated schematically in Figure 1. Alternatively ~'~ -5-1i~7~55~3 a groove or the like may be provided so that adjustment to the attachment means can be infinitely variable. A
groove essentially similar to that illustrated in Figure 7 can be used. The journal pin 12 or the like is locked against displacement in the groove by locking shoulders 16, illustrated in Figure 7, which can be locked in the groove in a manner not shown.

It is also preferred that at least one eccentric device 6 (Figure 1) is arranged for movement substantially in the longitudinal direction of the work-piece 1, preferably while maintaining a substantically constant distance between the rotary axes 8 of the eccentric devices. This displacement of the one eccentric device is intended to change the charac-teristics of the sawing process. Figures 1 and 2 illustrate an embodiment in which each shaft 9 can be displaced in a groove 17 provided in a wall 18.

According to one preferred embodiment the end parts 7 are constructed so that the two end parts rotate in opposite directions, as illustrated in Figure 1.
However, the end parts may be constructed in accordance with Figure 5, so that the end parts rotate the same direction.

The embodiment illustrated in Figures 1, 2 and 6 is intended for sawing a workpiece in both directions 1;~79~5~

of movement of the blade. In this case there is con-veniently used a saw blade 3 which has a neutral or non-toothed part 3' located centrally of the blade. Two blade parts 3''' are provided on one such saw blade and the saw teeth 3''' on both sides of the neutral blade part are provided with a cutting side which faces the neutral blade part and slopes towards the neutral part.
The blades are intended to move during a sawing action so that the workpiece is sawn with alternate parts 3'' of the blades.

The method according to the invention and the manner in which the arrangement according to the inven-tion operates will be understood in all essential details from the above.

Thus, the end parts 7 are rotated by means of the eccentric devices 6 and the saw blades attached to the attachment devices 4 move backwards and forwards at the same time. This reciprocating blade movement is characterized by a slower and therefore extended retar-dation and acceleration. In accordance with the embodi-ment illustrated in Figures 1 and 2 the saw blades move in a figure of eight. Thus, the sawing process is effected with the aid of one part of a blade during the whole of the blade movement. With the emboidment of Figure 5 the blade executes a rotary movement.

1~795~9 In the embodiment according to Figures 1, 2 and 6, the workpiece is sawn with the upper part 3'' during downward movement of the blade, and with the lower blade part 3'' during the upward movement of the blade, as illustrated schematically in Figure 6. In this case the workpiece 1 is advanced continuously. Sawing is effected so that a saw blade will not pass through the bottom and upper surfaces 1', 1 " of the workpiece during sawing.
This avoids splitting of the workpiece. Preferably, when sawing is continuous, sawing of the workpiece is com-menced at the surface 1', 1 " against which the blade 3 moves, i.e. 1 " in the left part of Figure 6 and 1' in the right part of said Figure. The workpiece is advanced in a manner which prevents the workpiece from being sawn through to the opposite surface. The workpiece is unable to split when sawn in this manner.

In the embodiment of Figure 5 the workpiece is preferably ad~anced more slowly, so that the workpiece is only sawn during downward movement of the blade.

The characteristics of the sawing process, such as the angle which the longitudinal axis of the blade forms with the longitudinal axis of the workpiece during a sawing process, can be changed by making a pronounced change to the radial distance a. That is the angle at ~;~795~9 which the blade is inclined to the workpiece can be altered by changing the distance a. Process charac-teristics, such as the above angle, can also be changed by displacing at least one eccentric device essentially in the direction of the longitudinal axis of the work-piece.

It will be apparent from the aforegoing that the method and the arrangement according to the invention afford considerable advantages over the prior art. Thus, the production rate can be substantially increased, for example doubled, since the workpiece is sawn in both directions of reciprocating blade movement. Furthermore, no guide systems need be provided. Thus, disadvantagbs in the form of frictional and fitting problems, asso-ciated with such guide systems, can be avoided. In addi-tion, unintentional sawing of a workpiece during a return stroke can be completely avoided~

In the aforegoing the invention has been described with reference to a number of ernbodiments thereof. It will be understoood, however, that other embodiments are conceivable and that minor modifications can be made wthout departing from the concept of the invention.

Thus, the saw and its components can be driven in various ways, not shown. Suitably driving can be 1~79SS9 effected via the shafts 9 of the eccentric devices which are not displaceable in the longitudinal direction of the workpiece, i.e. the lower eccentric devices in Figure 1.
In the majority of cases it should suffice for only one eccentric device to be driven. Driving can be effected with the aid of an electric motor, or in some other suitable manner.
It is also possible to have the workpiece, par-ticularly when made of metal, held stationary. In this case the saw is displaceable, such as raisable and lower-able, towards and away from the workpiece, substantially transversely to the longitudinal axis of the saw blade.

As will be understood, a number of essentially known embodiments of attachment devices 4, such as the frame 4, can be used to hold the blades 3. There is illustrated schematically one embodiment in which the blades are held tensioned by means of two mutually co-acting wedge portions 4', 4" in Figure 2. According to one embodiment a construction comprising twin attachment devices is conceivable. In this respect the blades 3 are arranged in a removable, loose frame (not shown), which is fitted in a preferably lightweight and readily removed frame. The fitting frame co-acts with the eccentric devices 6.

-lZ'~9559 Figure 6 illustrates an example of one con-figuration of a saw blade, this configuration having been described above. The use of neutral blades, however, is also conceivable when practicing the inven-tion.

Consequently, the invention shall not be con-sidered to be restricted to the aforedescribed embodi-ments, since modifications hereof can be carried out within the scope of the following claims.

Claims (25)

1. A method for sawing workpieces in frame saws in which at least one saw blade, arranged in an attachment device, reciprocates to saw a workpiece during at least a part of said blade reciprocation as the work-piece is advanced towards the blade characterized in that said blade reciprocation is effected with the aid of two eccentric devices, each of which is journalled to and co-acts with a respective one of two end parts of the attachment device, wherein at least one blade is intended to extend substantially between said end parts and each end part executes a rotary movement about the rotational axis of the particular eccentric device located at said end part.
2. A method according to Claim 1, in which the radial distance between the rotary axis of the eccentric device and the rotational centre of the journal connection between the eccentric device and said end part is substantially the same for both eccentric devices.
3. A method according to Claim 1, in which the radial distance between the rotary axis of the eccentric device and the rotational centre of the journal connection between the eccentric device and said end part is different for the two devices.
4. A method according to Claim 3, in which the rotational centre of said journal connection is displaced radially during the rotary movement of at least the one eccentric device.
5. A method according to Claim 2, charac-terized in that the characteristics of a sawing process are changed by changing said radial distance.
6. A method according to Claim 5 in which the sawing process characteristic is the angle that the blades form with the longitudinal axis of the workpiece during the sawing process.
7. A method according to Claim 1 in which the characteristics of a sawing process, are changed by displacing at least one eccentric device substantially in the longitudinal direction of the workpiece.
8. A method according to Claim 7 in which the characteristic that is changed is the angle that the at least one blade forms with the longitudinal axis of the workpiece during sawing.
9. A method according to Claim 7 in which a substantially constant distance is maintained between the rotary axes of the eccentric devices while displacing the at least one eccentric device.
10. A method according to any one of Claims 1 to 3 in which the end parts are rotated in mutually dif-ferent directions, so that blade parts intended for sawing action are moved in figure-of-eight path.
11. A method according to any one of Claims 1 to 3 in which the end parts are moved in the same direction.
12. A method according to Claim 1 in which saw blades are used that have a neutral part located centrally in the longitudinal direction of said blades, there being found in each such blade two blade parts, the saw teeth on both sades of said neutral part being formed with a cutting side which faces said neutral part, said blade being moved during a sawing action in a manner such that the workpiece is cut alternately with each of said blade parts.
13. A method according to claim 12 in which the cutting side of each blade part is inclined towards the neutral part.
14. A method according to any one of Claims 1 to 3 in which, when the workpiece is sawn continuously, the sawing process is effected such that the workpiece is initally cut at the surface against which the blade moves, and such that the workpiece is advanced in a manner which prevents the blade from penetrating to the opposite surface.
15. An arrangement in frame-sawing apparatus in which at least one saw blade attached to a blade-attachment device is adapted to execute a substantially reciprocating movement, and in which sawing of a work-piece advanced towards the blade is intended to take place during at least a part of said blade movement, characterized in that said blade movement is effected by two eccentric devices each of which is journalled to and co-acts with one of two end parts of the attachment device, wherein at least one blade extends substan-tially between said end parts, and wherein each end part is arranged to execute a rotary movement about the rotary axis of the eccentric device located at said end part.
16. An arrangement according to Claim 15 in which the radial distance between the rotary axis of the eccentric device and the rotational centre of the journal connection between the eccentric device and said end part is substantially the same for both eccentric device.
17. An arrangement according to Claim 15 in which the radial distance between the rotary axis of the eccentric device and the rotational cente of the journal connection between the eccentric device and said end part is noticeably different for the two eccentric devices.
18. An arrangement according to claim 17 in which the rotational centre of the journal connection is radially displaceable during the rotary movement of at least the one eccentric device.
19. An arrangement according to any one of Claims 15 to 17 in which said radial distance can be changed, the characteristics of the sawing process being changed by changing said distance.
20. An arrangement according to Claim 15 in which at least one eccentric device is arranged for move-ment substantially in the longitudinal direction of the workpiece, the characteristics of the sawing process being changed as a result of such movement.
21. An arrangement according to Claim 20 in which a substantially constant distance is maintained between the rotational axes of the eccentric devices during the movement of the at least one eccentric device.
22. An arrangement according to any one of Claims 15 to 17 in which the end parts are rotated in mutually different directions to cause the blade parts effective in a sawing process to move in a figure-of-eight movement path.
23. An arrangement according to any of Claims 15 to 17 in which the end parts are arranged to rotate in the same direction.
24. An arrangement according to Claim 15 including saw blades which have a centrally located neutral part when seen in the direction of their longitu-dinal extension, two blade parts being provided on one such saw blade, and the saw teeth on both sides of said neutral part being provided with a cutting side which faces said neutral part, the blade being intended to move during a sawing process in a manner such that the work-piece is cut alternately with both parts of the blade.
25. An arrangement according to Claim 24 in which each cutting side is inclined towards the neutral part.
CA000536483A 1986-11-10 1987-05-06 Frame saw and a method for its use Expired - Lifetime CA1279559C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8604811A SE8604811L (en) 1986-11-10 1986-11-10 METHOD OF PROCESSING AND DEVICE FOR CARRYING OUT THE PROCEDURE
SE8604811-3 1986-11-10

Publications (1)

Publication Number Publication Date
CA1279559C true CA1279559C (en) 1991-01-29

Family

ID=20366243

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000536483A Expired - Lifetime CA1279559C (en) 1986-11-10 1987-05-06 Frame saw and a method for its use

Country Status (2)

Country Link
CA (1) CA1279559C (en)
SE (1) SE8604811L (en)

Also Published As

Publication number Publication date
SE8604811L (en) 1988-05-11
SE8604811D0 (en) 1986-11-10

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