WO1996011779A1

WO1996011779A1 - Saw bar and method for its manufacture

Info

Publication number: WO1996011779A1
Application number: PCT/SE1995/001169
Authority: WO
Inventors: Olofsson Johan Lennart
Original assignee: Olofsson Johan Lennart
Priority date: 1994-10-12
Filing date: 1995-10-11
Publication date: 1996-04-25
Also published as: SE9403460L; CA2200979A1; AU3714295A; JPH10507416A; FI971474A0; FI971474A; SE9403460D0; SE509573C2

Abstract

The present invention relates to a saw bar having a channel system (14) and a plurality of metal plates (1, 2 and 3). These metal plates have been joined together by laser welding. The invention also relates to a method for manufacturing such a saw bar. According to the invention there is provided in inner portions (27) a during operation of the saw bar heavily loaded portion (11) at least one inner weld joint (28 and/or 29 and/or 30 and/or 31) beside the channel system (14) in order to effectively reinforce said portion (11) and define a liquid sealing to a channel system (14) provided therein.

Description

Saw bar and method for its manufacture.

The present invention relates to a saw bar having a driven cutting chain which is located in grooves in edge portions of said saw bar, whereby the saw bar has at least two, preferably three, metal plates which are joi- ned together by means of one or more outer weld joints provided by laser welding and extending forward in the longitudinal direction of the saw bar towards a front end portion thereof, whereby the saw bar has a rear moun¬ ting portion through which said saw bar is adapted to be mounted on a drive assembly for driving said saw bar and whereby the saw bar is provided with a channel system for channeling at least a liquid, preferably lubricating oil, from the rear mounting portion and through a por¬ tion situated in front thereof and connecting thereto, in a forward direction towards the front end portion of the saw bar.

The present invention also relates to a method for manufacturing such a saw bar.

Saw bars of said type are already known from CA patent specification 1 198 967. At the saw bar according to this publication, the metal plates are joined by means of outer weld joints extending along the edge portions of the saw bar and provided by so called laser welding. This normally means that the metal alloy in the metal plates are remelted by concentrating the energy of the laser beam so that a homogeneous zone is defined.

Since the weld joints at this prior art saw bar ex¬ tend only along the edge portions, an optimum strong saw bar can not be obtained if said saw bar has a channel system for lubricating oil and/or other liquids.

Therefore, the object of the present invention has been to provide an optimum strong saw bar of the above¬ mentioned type, and this is arrived at according to the invention substantially by means of the characterizing features of claim 1. A simple method for manufacturing said saw bar is defined by the characterizing features of claim 16.

Since the saw bar has at least an inner weld joint, provided by laser welding, in inner portions of said saw bar and beside the channel system, an optimum strong saw bar can be obtained at reasonable costs and simul¬ taneously, a liquid sealing for the channel system is defined.

The invention will be further described below with reference to the accompanying drawings, wherein figure 1 is a plan view of a saw bar according to the invention, figures 2-7 are sections II-VII through the saw bar of figure 1 and figure 8 is a plan view of a part of an al¬ ternatively designed saw bar according to the invention. The saw bar illustrated in the drawings is of so called laminated type, which means that it consists of a number of metal plates which engage each other and which are joined together, so that a sandwich structure is defined. Thus, the saw bar as illustrated consists of three metal plates 1, 2 and 3 which are joined toget¬ her and designed so that grooves 5 for a cutting chain (not shown) are provided along edge portions 4 thereof.

The saw bar has a rear mounting portion 6 with a mounting groove 7 which extends from a rear edge portion 8 a substantial distance into said rear mounting portion 6. On opposite sides of the mounting groove 7 there are provided two mounting holes 9 and 10 which along with the mounting groove 7 are provided to receive mounting members on a conventional drive assembly (not shown) which is adapted to drive the cutting chain and which is mechanically or manually carried with the saw bar attached thereto or mounted thereon.

During sawing with the saw bar, particularly heavy loads are generated on that portion 11 of the saw bar which is situated in front of the rear mounting portion 6 and connected thereto, i.e. that portion 11 of the saw bar which is located immediately in front of a front end edge F of the mounting members of the drive assembly when the saw bar is mounted on said drive assembly.

At a front end portion 13 of the saw bar there is provided a sprocket (not shown) via which the cutting chain is intended to run.

The saw bar includes a channel system 14 for chan¬ neling or guiding liquids to the cutting chain. Thus, the channel system 14 may consist of one or more channels for channeling lubricating oil and/or another liquid such as liquids containing paint and/or bacteria to the saw bar. In the illustrated embodiment of the saw bar, the channel system 14 is provided in the intermediate metal plate 2 and it includes two inlet openings 15 and 16 in the rear mounting portion 6. Channel branches 17 and 18 respectively extend in a forward direction from said in¬ let openings 15, 16. These branches converge in portion 11 of the saw bar to a single channel 19 which extends centrally in the saw bar in a forward direction through the front portions 12 and near to the front end portion 13. In front, the channel 19 branches off to e.g. three channel branches of which a forwardly directed channel branch 20 may extend to a space for the sprocket, while two laterally directed channel branches 21 and 22 open into the groove 5 for the cutting chain at opposite long sides thereof.

Laser technique is used for joining the metal plates 1-3 while a laser assembly 23 is brought to direct its laser beam 24 towards the saw bar and by means of so cal¬ led laser welding with high energy remelt the metal alloy in the metal plates 1-3 and define homogeneous zones therebetween, namely preferably simultaneously between the metal plates 1 and 2 as between the metal plates 2 •and 3. It is also possible to laser weld two metal pla¬ tes at the time. With this laser technique a suitable weld joint pattern can be obtained by moving the saw bar in a suitable manner relative to the laser assembly or vice versa. In the illustrated embodiment of the saw bar there is provided with the same laser technique, in inner por¬ tions 27 of the portion 11 of the saw bar beside the channel system 14, at least one inner weld joint 28 and/ /or 29 and/or 30 and/or 31, which preferably runs conti¬ nuously in a forward direction through said portion 11 (see particularly figs. 5 and 6) . This inner weld joint 28-31 is adapted to join together the metal plates 1-3 in the inner portions 27 of the portion 11 and thereby reinforce and stiffen at least said inner portions 27 of the saw bar. The inner or interior weld joint 28 and/or 29 and/or 30 and/or 31 can also define liquid sealings for the channel system 14 by extending continuously there- along or by being located in another suitable manner in relation thereto.

The locations of the inner weld joints 28-31 in at least the portion 11 are adapted to the requirements set with regard to reinforcement of inner portions of the saw bar and also to the design of the channel system 14, whereby said inner weld joints preferably are located at a least distance of 0,5 mm and a largest distance of 5 mm from at least a part of the channels of the channel system 14. Furthermore, inner edge weld joints 36, 37 are preferably located at a least distance of 0,5 mm and a largest distance of 7 mm from the mounting groove 7 and/or the mounting holes 9, 10.

At the illustrated design of the saw bar there are provided in the portion 11 two pairs of inner weld joints 28, 30 and 29, 31 respectively. These are preferably lo- cated on opposite sides of the channel 19 and start pre¬ ferably in the rear mounting portion 6 and extend conti¬ nuously in forward direction through the portion 11 along said channel 19 to the front portions 12 and end therein. The inner weld joints 28-31 extend preferably recti- linearly or somewhat arcuately relative to each other along the saw bar.

At the back, the weld joints 28, 30 can be connec- ted with each other through a connecting weld joint 32 and the weld joints 29, 31 through a connecting weld joint 33.

The weld joints 30, 31 run forward in the front por- tions 12 of the saw bar, preferably substantially longer than the weld joints 28, 29, and each weld joint 30, 31 has at the front preferably an inwardly directed front portion 34, 35 which is facing or directed towards the channel 19 so that said channel can pass between said front portions 34, 35.

The distances between the weld joints 28-31 may be substantially equal.

In the rear mounting portion 6 there are preferably provided two edge weld joints 36 and 37 respectively, which extend continuously along the long sides of the moun¬ ting groove 7 and which preferably are connected with each other through the bottom edge of said mounting groove via a bottom edge weld joint 38. Each edge weld joint 36 and 37 respectively, connects with or joins such a portion of an outer weld joint 25 and 26 respectively, which runs along the rear edge portion 8. Each edge weld joint 36, 37 runs preferably between the mounting groove 7 and each mounting hole 9 and 10 respectively, provided on opposite sides thereof. Furthermore, each edge weld joint 36 and 37 respec¬ tively, is preferably provided so that it extends conti¬ nuously along the inner side of at least a part of each channel branch 17 and 18 respectively, while portions of the inner weld joints 28 and 29 respectively, extend continuously along at least parts of the outer side of each channel branch 17 and 18 respectively.

Along said outer side of each channel branch 17 and 18 respectively, there may also extend a portion of an outer weld joint 25 and 26 respectively, and each connec- ting weld joint 32 and 33 respectively, may connect with said portion to define a continuous sealing along one side of each channel branch 17 and 18 respectively. In the rear mounting portion 6 there may also be pro¬ vided inner, short weld joints 39 and 40 which connect with or join the edge weld joints 36, 37 and which extend along portions of the inside of said channel branches 17 and 18 respectively, and end at about each inlet opening 15 and 16 respectively, or eventually extend beyond said opening in backward/outward direction and connect with each outer weld joint 25 and 26 respectively.

Two inner front weld joints 41 and 42 may be inclu- ded in the front portions 12 of the saw bar and said weld joints 41, 42 are preferably provided immediately behind the front end portion 13 , wherein the sprocket is adapted to be mounted. Each such weld joint 41, 42 preferably has an endless shape, e.g. substantially rectangular shape, and a portion of said weld joint 41 and 42 respectively, may extend along a front side of one of the laterally directed channel branches 21 and 22 respectively. Along the rear side of said channel branch 21 and 22 respec¬ tively, there may run an inwardly directed front portion 43 and 44 respectively, of each outer weld joint 25 and 26 respectively. These inwardly directed portions 43, 44 of the outer weld joints 25, 26 end at a distance from each other so that the channel 19 can pass therebetween. The saw bar is manufactured so that the metal pla- tes 1, 2 and 3 are placed on top of each other, where¬ after they are joined together by providing the weld joints by means of the laser assembly 23, whereby one or more weld joints 28-31 are located at least in the inner portions 27 of part or portion 11 for extensive reinforce- ment thereof. The metal plates 1, 2, 3 may be heated to e.g. at least 150°C and 640°C at the most before or during the process of joining said plates together.

Furthermore, the metal plates 1, 2 and 3 may, during the process of joining said plates together, be subjec- ted to outer pressure, preferably at their edge portions 4, so that said plates engage each other with a pressure thus obtained. The invention is not limited to the abovementioned embodiment and manufacturing method, but may vary within the scope of the following claims. Thus, inner weld joints may be provided in a totally different pattern than illu¬ strated in fig. 1. As is apparent from fig. 8, inner weld joints 28, 29 may extend in accordance with a sine curve (schematically illustrated with dashed and dotted lines) which extend back and forth from the inner portions 27 to near or adjacent the edge portions 4 and vice versa.

Claims

Claims :

1. Saw bar having a driven cutting chain which is located in grooves (5) in edge portions (4) of said saw bar, whereby the saw bar has at least two, preferably three, metal plates (1-3) which are joined together by means of one or more outer weld joints (25, 26) provided by laser welding and extending forward in the longitudi¬ nal direction of the saw bar towards a front end portion (13) thereof, whereby the saw bar has a rear mounting portion (6) through which said saw bar is adapted to be mounted on a drive assembly for driving said saw bar, and whereby the saw bar is provided with a channel sys¬ tem (14) for channeling at least a liquid, preferably lubricating oil, from the rear mounting portion (6) and through a portion (11) situated in front thereof and connecting thereto, in a forward direction towards the front end portion (13) of the saw bar, c h a r a c t e r i z e d i n that the saw bar has at least one inner, by laser welding provided weld joint (28 and/or 29 and/or 30 and/ /or 31) which joins together at least two, preferably three, metal plates (1-3), that the inner weld joint (28 and/or 29 and/or 30 and/or 31) , relative to the edge portion or edge por¬ tions (4) of the saw bar is provided within the outer weld joint(s) (25, 26), that the inner weld joint (28 and/or 29 and/or 30 and/or 31) at least partially is provided in inner por- tions (27) of the portion (11) connecting to the the rear mounting portion (6) of the saw bar, and that the inner weld joint (28 and/or 29 and/or 30 and/or 31) is provided to run along a channel (17 and/or 18 and/or 19) forming part of the channel system (14) in order to define a liquid sealing therefor.

2. Saw bar according to claim 1, c h a r a c t e ¬ r i z e d i n that the inner weld joint (28 and/or 29 and/or 30 and/or 31) is provided to extend continuously along at least one channel (17 and/or 18 and/or 19) of the channel system (14) .

3. Saw bar according to claim 1 or 2, c h a r a c ¬ t e r i z e d i n that the inner weld joint (28 and/or 29 and/or 30 and/or 31) starts in the rear mounting por¬ tion (6) and extends therefrom in a forward direction through the portion (11) connecting to said mounting por¬ tion (6) and into front portions (12) of said saw bar.

4. Saw bar according to any preceding claim, c h a ¬ r a c t e r i z e d i n that two inner weld joints

(28, 29) are provided on opposite sides of at least one such channel (19) in the channel system (14) which is located in the portion (11) connecting to the mounting portion (6) .

5. Saw bar according to any preceding claim, c h a ¬ r a c t e r i z e d i n that the portion (11) connec- ting to the mounting pc -tion (6) has at least two pairs of inner weld joints (IS, 30 and 29,31), whereby each pair of weld joints (28, 30 and 29, 31 respectively), in¬ cludes a shorter weld joint (28 and 29 respectively) and a longer weld joint (30 and 31 respectively) .

6. Saw bar according to claim 5, c h a r a c t e ¬ r i z e d i n that a first pair of weld joints (28, 30) is provided on one side of at least one such channel (19) in the channel system (14) which is located in the por¬ tion (11) connecting to the mounting portion (6), and that a second pair of inner weld joints (29, 31) is pro¬ vided on the other side of said channel (19) .

7. Saw bar according to any of claims 4-6, c h a ¬ r a c t e r i z e d i n that the weld joints in each pair of inner weld joints (28, 30 and 29, 31 respectively) are at the rear connected with each other through a con¬ necting weld joint (32 and 33 respectively) .

8. Saw bar according to any of claims 4-7, c h a ¬ r a c t e r i z e d i n that rear portions of each pair of weld joints (28, 30 and 29, 31 respectively) are provided outside a mounting groove (7) which is adapted to receive mounting portions for the drive assembly.

9. Saw bar according to any of claims 4-8, c h a ¬ r a c t e r i z e d i n that one of the inner weld joints (30, 31) in each pair thereof extends in forward direction substantially farther into the front portions (12) of the saw bar than the other inner weld joint (28, 29) in said pair of inner weld joints, that preferably the farther into the front portions (12) of the saw bar extending weld joint (30 and 31 respectively) is loca¬ ted outside the other weld joint (28 and 29 respectively) in said pair of weld joints, that the weld joint (30 and 31 respectively) extending farther into the front portions (12) of the saw bar at the front preferably has an inwardly directed front portion (34 and 35 respective¬ ly) which is facing or directed towards a channel (19) in the channel system (14) and that the inner weld joints (28-31) preferably run continuously and rectilinearly or somewhat arcuately along each other in the longitudi¬ nal direction of the saw bar.

10. Saw bar according to any preceding claim, c h a r a c t e r i z e d i n that at least an inner weld joint or a portion thereof is provided to extend along such a channel branch (17 or 18) in the channel system (14) which runs from an inlet opening (15 and 16 respectively) and which together with another channel branch (18 or 17) extends to a channel (19) located cent¬ rally in the saw bar.

11. Saw bar according to any preceding claim, c h a r a c t e r i z e d i n that at least one inner weld joint (28 and/or 29) is sinusoidal and runs back and forth from inner portions (27) of the saw bar to near longitudinal edge portions (4) of the saw bar and vice versa.

12. Saw bar according to any preceding claim, c h a r a c t e r i z e d i n that at least one inner weld joint (28-31) extends at least partially along a channel in the channel system (14) at a distance of at least 0, 5 mm and maximum 5 mm from said channel.

13. Saw bar according to any preceding claim, c h a r a c t e r i z e d i n that the rear mounting portion (6) has an inner edge weld joint (36 and/or 37) which is provided to run along at least one longer side, preferably two opposed longer sides, of a mounting groove (7) , which extends from a rear edge portion (8) of the saw bar a distance into said saw bar and which is adapted to receive mounting members of the drive assembly.

14. Saw bar according to claim 13, c h a r a c - t e r i z e d i n that two edge weld joints (36, 37) extending along two opposite longer sides of the moun¬ ting - roove (7) are connected with each other through a bottc..,. edge weld joint (38) running along a bottom edge of said groove (7) .

15. Saw bar according to claim 13 or 14, c h a ¬ r a c t e r i z e d i n that at least one edge weld joint (36 and/or 37) connects with an outer weld joint (25 and 26 respectively) which runs along the rear edge portion (8) of the saw bar.

16. Saw bar according to any of claims 13-15, c h a r a c t e r i z e d i n that at least a portion of an inner edge weld joint (36 and/or 37) is located be¬ tween the mounting groove (7) and a mounting hole (9 and/ /or 10) provided in the saw bar beside said groove and adapted to receive mounting members of the drive assembly.

17. Saw bar according to any of claims 13-16, c h a r a c t e r i z e d i n that the rear mounting portion (6) includes at least an inner, short weld joint (39 and/or 40) which connects with an edge weld joint (36 and/or 37) which runs along the mounting groove (7) , said inner short weld joint (39 and/or 40) preferably at least partially extends a^"1 "-g such a channel branch (17 and/or 18) in the channel system (14) which runs from an inlet opening (15 and/or 16) in the saw bar, said ope¬ ning forming part of the channel system (14) .

18. Saw bar according to any of claims 13-17, c h a r a c t e r i z e d i n that each inner edge weld joint (36 and/or 37) which extends along the moun¬ ting groove (7) and/or one or more mounting holes (9 and/ /or 10) which is/are adapted to receive mounting members on the drive assembly, is located 0,5 mm and maximum 7 mm from the mounting groove (7) and/or a mounting hole (9 and/or 10) .

19. Saw bar according to any preceding claim, c h a r a c t e r i z e d i n that front portions (12) of the saw bar includes at least one inner front weld joint (41 and/or 42) and preferably two inner front weld joints (41, 42) which are located immediately behind such a front end portion (13) of the saw bar which is adapted to include a sprocket for the cutting chain.

20. Saw bar according to claim 19, c h a r a c - t e r i z e d i n that the inner front weld joint (s)

(41, 42) is/are provided in front of an inwardly direc¬ ted front portion (43 and 44 respectively) of one or more outer weld joints (25 and 26 respectively) , that every inner front weld joint (41 and 42 respectively) preferably has an endless shape, e.g. a substantially rectangular shape, and that at least a portion of each inner front weld joint (41 and 42 respectively) preferably runs along a channel branch (21 and 22 respectively) of the channel system (14) .

21. Saw bar according to any preceding claim, c h a r a c t e r i z e d i n that the outer weld joints (25, 26) extend along a rear edge portion (8) of the saw bar and connect with edge weld joints (36, 37) at a mounting groove (7) at said edge portion (8) and that the outer weld joints (25, 26) in front portions (12) of the saw bar open on opposite sides of a channel (19) in the channel system (14) .

22. Method for manufacturing saw bars having a dri¬ ven cutting chain which is located in a groove (5) in edge portions (4) of said saw bar, whereby the saw bar is provided with at least two, preferably three, metal plates (1, 2 and 3) which are joined together by means of one or more outer weld joints (25 and/or 26) provided by laser welding, c h a r a c t e r i z e d b y providing at least one inner weld joint (28 and/or 29 and/or 30 and/or 31) by means of laser welding, loca¬ ting said weld joint relative to the edge portion or edge portions (4) of the saw bar within the outer weld joint or outer weld joints (25 and/or 26) and locating said weld joint in inner portions (27) of at least one portion (11) of the saw bar which is situated in front of and connects to a rear mounting portion (6) of said saw bar, whereby said inner portions (27) are reinforced by the inner weld joint (28 and/or 29 and/or 30 and/or 31), locating said inner weld joint (28 and/or 29 and/or 30 and/or 31) to extend along a channel (17 and/or 18 and/ /or 19) forming part of the channel system (14) and loca¬ ted in said portion (27) of the saw bar for defining a liquid sealing to said channel (17 and/or 18 and/or 19) , providing at least one weld joint (36 and/or 37) by means of laser welding and locating said weld joint in rear portions (6) of the saw bar to extend along at least portions of opposite longer sides of a mounting groove (7) for reinforcement of said rear portions (6) , and providing at least one weld joint (41 and/or 42) by laser welding and locating said weld joint in front portions (12) of the saw bar for reinforcement of said front portions (12).

23. Method according to claim 22, c h a r a c t e ¬ r i z e d b y heating the metal plates (1, 2 and 3) before and/or during the joining together thereof to at least 150°C and maximum 640°C.

24. Method according to claim 22 or 23, c h a ¬ r a c t e r i z e d b y subjecting the metal plates (1, 2 and 3) during the joining together thereof, to an outer pressure, preferably at edge portions thereof, so that said metal plates engage each other with a pressure thus generated.