CA2147899C - Saw blade drive system - Google Patents
Saw blade drive systemInfo
- Publication number
- CA2147899C CA2147899C CA 2147899 CA2147899A CA2147899C CA 2147899 C CA2147899 C CA 2147899C CA 2147899 CA2147899 CA 2147899 CA 2147899 A CA2147899 A CA 2147899A CA 2147899 C CA2147899 C CA 2147899C
- Authority
- CA
- Canada
- Prior art keywords
- drive
- sawblade
- spline
- radials
- angular distance
- 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 - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
- B23D61/00—Tools for sawing machines or sawing devices; Clamping devices for these tools
- B23D61/02—Circular saw blades
- B23D61/025—Details of saw blade body
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
- B27B5/00—Sawing machines working with circular or cylindrical saw blades; Components or equipment therefor
- B27B5/29—Details; Component parts; Accessories
- B27B5/30—Details; Component parts; Accessories for mounting or securing saw blades or saw spindles
- B27B5/32—Devices for securing circular saw blades to the saw spindle
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Sawing (AREA)
Abstract
A sawblade and a drive spline having a drive configuration therebetween. The drive configuration comprises inner driven surfaces on the sawblade which are driven by the drive spline which has outer drive recesses complementary to the inner driven surfaces of the sawblade. First and second radials extend outwardly from the axis of rotation of the drive spline and sawblade.
They extend so as to contact the ends of a respective recess or drive surface most closely located to the axis of rotation. Second and third radials extend to contact the ends of the most remotely located recess or drive surface. The angular distance between the first and second radials is greater than the angular distance between the third and fourth radials.
They extend so as to contact the ends of a respective recess or drive surface most closely located to the axis of rotation. Second and third radials extend to contact the ends of the most remotely located recess or drive surface. The angular distance between the first and second radials is greater than the angular distance between the third and fourth radials.
Description
- 21~7899 INTROL~ LlON
This invention relates to a saw blade and a drive system therefore and, more particularly, to a sawblade and its associated drive spline having a specific driving configuration.
RACK~ROUND OF THE lNv~NllON
Circular type sawblades to cut cants or lumber are, of course, known together with their associated drive splines. Typically, the drive spline has a series of rounded or convex male drive pieces spaced intermittently and circumferentially around the drive spline. They mate with correspo~; ng concave female recesses in the saw blade. Typically, the sawblade is mounted onto the drive ~pline endwise. It slides over the spline until the desired operating position on the drive spline is reached. Under operating conditions, the sawblade is maintained in its desired position with sawguides which prevent undesirable movement in the sawblade. This keeps the kerf or cutting width created by the blade narrow which i~ desirable in order not to avoid wood wastage during the sawing operation.
The drive spline used with the aforementioned convex male driving pieces has problems. Such problems relate to safety, tolerances and sawblade driving efficiency.
In respect of the former, there has arisen the unfortunate practise of "tree spiking" by those protective of logs which they feel should not be felled.
This practise involves driving large nails or spikes into - 21~7~99 the trunks of trees before cutting. Often the spikes are not readily observed by either the fellers or the sawmill operators with the result that during sawmill operations, the sawblade may strike a spike within the cant or log during the cutting operation. This i8 a most dangerous occurrence since the sawblade can tear or fragment and pieces of shrapnel are distributed at high energy levels throughout the area where the cutting is tAk;ng place.
This disintegration takes place because there is no retention of the sawblade by the spline when the sawblade splits or tears after contact with the spike. Sawmill operators lives have been lost and their injuries have been severe because of these tree spiking practises. It would be advantageous if the sawblade did not tear away from the drive spline under such conditions.
Yet a further disadvantage with present sawblades and the convex type drive splines relates to operating tolerances. Because of the convex type drive spline which mates with correspo~;ng type recesses in the sawblade, a series of point contacts occurs when the two curved surfaces meet. This point contact results in a series of high stress points between the drive spline and the sawblade which increases wear on both members and reduces the driving efficiency between the spline and the sawblade.
Yet a further disadvantage with the present sawblade-drive spline system is that the position of the sawblade on the drive spline can change during operation.
This is 80 because there are tolerances between the convex drive surfaces of the drive spline and the concave driven surfaces of the sawblade. The saw blade will move upwardly and downwardly on the spline during operation while various impact loadings occur and the sawblade moves upwardly and downwardly on the spline through these tolerances. Thus, the actual driving efficiency is adversely affected.
Yet a further disadvantage with the present drive spline design is the fact that the spline has to be hardened to a hardness greater than that of the blade.
This practise is time consuming and expensive.
SUMMARY OF THE lNv~NllON
According to one aspect of the invention, there is provided a sawblade of circular configuration having an axis of rotation, an outer cutting edge and a plurality of inner driven surfaces defined by a first angular distance between a first and second radial, said first and second radials contacting each end of a respective one of said driven surfaces located most closely to said axis of rotation, and a second angular distance between a third and fourth radial, said third and fourth radials contacting each end of ~aid respective one of said driven surfaces located most remotely from said axis of rotation, the angular distance between said first and second radials being greater than the angular distance between said third and fourth radial~.
According to a further aspect of the invention, there is provided a drive spline of circular configuration having an axis of rotation, a plurality of outer drive recesses defined by a first angular distance between a first and second radial, said first and second radials contacting each end of a respective one of said drive recesses located most closely to said axis of rotation and a second angular distance between a third and fourth radial, said third and fourth radials contacting each end of a respective one of said drive recesses located most remotely from said axis of '- 2147899 rotation, the angular distance between said first and second radials being greater than the angular di~tance between ~aid third and fourth radial~.
According to a further aspect of the invention, there is provided a drive spline of circular configuration having an axis of rotation, said drive spline having a plurality of drive recesses having replaceable drive surfaces along first angular distance between a first and second radial, said drive surfaces ext~n~;ng axially along said drive spline.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
A specific embodiment of the invention will now be described, by way of example only, with the use of drawings in which:
Figure 1 is a side diagrammatic view of a circular sawblade mounted on a drive spline which, in turn, is mounted on an arbor, the sawblade and drive ~pline having a configuration according to the invention;
Figure 2 is a side diagrammatic enlarged view of a circular sawblade mounted on a drive spline and illustrating the drive configuration between the spline and the sawblade according to a first embodiment of the invention;
Figure 3 is an enlarged view of the circular ~awblade of Figure 2;
Figure~ 4A, 4B, 4C and 4D are enlarged views of four different drive spline configurations according to a further aspect of the invention; and Figure 5 is an enlarged view of an insert according to a further aspect of the invention.
DESCRIPTION OF SPECIFIC EMBODIMENT
Referring now to the drawings and, more particularly, to Figure 1, a circular ~awblade 10 i8 mounted on a drive spline 11 which, in turn, is mounted on an arbor 12. Arbor 12 is journalled in bearings 13 and a source of turning power for the arbor 12 is provided (not shown) which is then transferred to the sawblade 10 to turn the sawblade 10 and cut the wood diagrammatically illustrated at 14. A pair of sawguides 20 are mounted on either side of the circular sawblade 10. They guide the sawblade 10 and can move it axially on the drive spline 11. It will be appreciated, of course, that a plurality of sawblades could be mounted on the drive spline 11 depen~; ng on the lumber which is being cut and the desire~ of the operator.
Reference is now made to Figure 2 which illustrates the sawblade 10 mounted on the drive spline 11. The drive spline 11 and sawblade 10 have a common axis of rotation 21 and, under operation, the sawblade 10 rotates clockwise as seen by the arrows. A ~eries of inner driven surfaces 22 of sawblade 10 are complementary to outer drive rece~ses 23 of drive spline 11. The inner distance 24 of drive surface 22 is greater that the outer distance 25 such that if the sawblade contacts a foreign object such a spike in a tree being cut, the blade 10 will not be hurled from the drive spline 11 but will be ret~; ne~ by the drive spline 11 such that the operator may immediately terminate operation of the drive system.
More particularly, the out~ide circumference of the drive spline is indicated by first diameter dio and the inside diameter of the drive spline is indicated by second diameter d2i. The distance between dio and d2i is the distance between the outer diameter of the drive spline 11 and the most inwardly distance of the drive 5 recess 23.
First and second radials r1, r2 are drawn from the axis of rotation 21 to touch the ends of the drive recess 23 located most closely to axis 21. Third and 10 fourth radials r3, r4 are drawn from the axis of rotation 21 to touch the ends of the drive recess 23 located most remotely from axis 21. The angular distance between rl and r2 will be larger than the distance between r3 and r4 as can clearly be seen from Figures 2 and 3.
For example, in a first embodiment of the invention as illustrated in Figure 2, the distance between the ends of the drive recess 23 located closest to axis 21 is . 597 in. as illustrated. This di~tance is 20 obtained by drawing radials to each of the ends of the drive recess 23 and measuring the distance of . 597. A 60 degree angle is cut into the drive spline 23 and a surface is formed 90 degrees to the line defining the distance of . 597 in. which meets the 60 degree angle cut.
This surface defines the most advanced point of the radial rl and the most retarded point of radial r2.
It will be readily seen that a number of different configurations for the drive recesses 23 of drive spline 11 and the drive surfaces 22 of sawblade 10 could be used in order to achieve the benefits of the present invention. Reference is made, for example, to Figures 4A, 4B, 4C and 4D.
In Figure 4A, drive surfaces 30 take a somewhat partially convex configuration and in Figure 4B, drive 21~7899 surfaces 32 take on an appearance similar to the drive surfaces 22 of Figures 2 and 3 but extend inwardly a much greater distance. However, it remains the case that the angular distance e1 between the radials r1, r2 is less that the angular distance e2 between the radials r3, r4.
Figures 4C and 4D illustrate two further drive configurations according to further aspects of the invention. In each of these configurations, there is a drive surface 40, 41 which has an angle ~ relative to radial r3 which is greater than zero degrees. Thus, there will be a partial ret~;n;ng effect executed on the sawblade 43 by the forces executed between drive surfaces 41, 42 of the spline by the sawblade.
In Figure 5, replaceable drive surfaces 34 are located along removable inserts made of hardened steel material 35 ext~n~;ng axially along the spline 11, and being secured to the drive spline with bolts 36.
While specific embodiments of the invention have been described, such descriptions should be taken as illustrative of the invention only and not as limiting its scope as defined in accordance with the accompanying claims.
This invention relates to a saw blade and a drive system therefore and, more particularly, to a sawblade and its associated drive spline having a specific driving configuration.
RACK~ROUND OF THE lNv~NllON
Circular type sawblades to cut cants or lumber are, of course, known together with their associated drive splines. Typically, the drive spline has a series of rounded or convex male drive pieces spaced intermittently and circumferentially around the drive spline. They mate with correspo~; ng concave female recesses in the saw blade. Typically, the sawblade is mounted onto the drive ~pline endwise. It slides over the spline until the desired operating position on the drive spline is reached. Under operating conditions, the sawblade is maintained in its desired position with sawguides which prevent undesirable movement in the sawblade. This keeps the kerf or cutting width created by the blade narrow which i~ desirable in order not to avoid wood wastage during the sawing operation.
The drive spline used with the aforementioned convex male driving pieces has problems. Such problems relate to safety, tolerances and sawblade driving efficiency.
In respect of the former, there has arisen the unfortunate practise of "tree spiking" by those protective of logs which they feel should not be felled.
This practise involves driving large nails or spikes into - 21~7~99 the trunks of trees before cutting. Often the spikes are not readily observed by either the fellers or the sawmill operators with the result that during sawmill operations, the sawblade may strike a spike within the cant or log during the cutting operation. This i8 a most dangerous occurrence since the sawblade can tear or fragment and pieces of shrapnel are distributed at high energy levels throughout the area where the cutting is tAk;ng place.
This disintegration takes place because there is no retention of the sawblade by the spline when the sawblade splits or tears after contact with the spike. Sawmill operators lives have been lost and their injuries have been severe because of these tree spiking practises. It would be advantageous if the sawblade did not tear away from the drive spline under such conditions.
Yet a further disadvantage with present sawblades and the convex type drive splines relates to operating tolerances. Because of the convex type drive spline which mates with correspo~;ng type recesses in the sawblade, a series of point contacts occurs when the two curved surfaces meet. This point contact results in a series of high stress points between the drive spline and the sawblade which increases wear on both members and reduces the driving efficiency between the spline and the sawblade.
Yet a further disadvantage with the present sawblade-drive spline system is that the position of the sawblade on the drive spline can change during operation.
This is 80 because there are tolerances between the convex drive surfaces of the drive spline and the concave driven surfaces of the sawblade. The saw blade will move upwardly and downwardly on the spline during operation while various impact loadings occur and the sawblade moves upwardly and downwardly on the spline through these tolerances. Thus, the actual driving efficiency is adversely affected.
Yet a further disadvantage with the present drive spline design is the fact that the spline has to be hardened to a hardness greater than that of the blade.
This practise is time consuming and expensive.
SUMMARY OF THE lNv~NllON
According to one aspect of the invention, there is provided a sawblade of circular configuration having an axis of rotation, an outer cutting edge and a plurality of inner driven surfaces defined by a first angular distance between a first and second radial, said first and second radials contacting each end of a respective one of said driven surfaces located most closely to said axis of rotation, and a second angular distance between a third and fourth radial, said third and fourth radials contacting each end of ~aid respective one of said driven surfaces located most remotely from said axis of rotation, the angular distance between said first and second radials being greater than the angular distance between said third and fourth radial~.
According to a further aspect of the invention, there is provided a drive spline of circular configuration having an axis of rotation, a plurality of outer drive recesses defined by a first angular distance between a first and second radial, said first and second radials contacting each end of a respective one of said drive recesses located most closely to said axis of rotation and a second angular distance between a third and fourth radial, said third and fourth radials contacting each end of a respective one of said drive recesses located most remotely from said axis of '- 2147899 rotation, the angular distance between said first and second radials being greater than the angular di~tance between ~aid third and fourth radial~.
According to a further aspect of the invention, there is provided a drive spline of circular configuration having an axis of rotation, said drive spline having a plurality of drive recesses having replaceable drive surfaces along first angular distance between a first and second radial, said drive surfaces ext~n~;ng axially along said drive spline.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
A specific embodiment of the invention will now be described, by way of example only, with the use of drawings in which:
Figure 1 is a side diagrammatic view of a circular sawblade mounted on a drive spline which, in turn, is mounted on an arbor, the sawblade and drive ~pline having a configuration according to the invention;
Figure 2 is a side diagrammatic enlarged view of a circular sawblade mounted on a drive spline and illustrating the drive configuration between the spline and the sawblade according to a first embodiment of the invention;
Figure 3 is an enlarged view of the circular ~awblade of Figure 2;
Figure~ 4A, 4B, 4C and 4D are enlarged views of four different drive spline configurations according to a further aspect of the invention; and Figure 5 is an enlarged view of an insert according to a further aspect of the invention.
DESCRIPTION OF SPECIFIC EMBODIMENT
Referring now to the drawings and, more particularly, to Figure 1, a circular ~awblade 10 i8 mounted on a drive spline 11 which, in turn, is mounted on an arbor 12. Arbor 12 is journalled in bearings 13 and a source of turning power for the arbor 12 is provided (not shown) which is then transferred to the sawblade 10 to turn the sawblade 10 and cut the wood diagrammatically illustrated at 14. A pair of sawguides 20 are mounted on either side of the circular sawblade 10. They guide the sawblade 10 and can move it axially on the drive spline 11. It will be appreciated, of course, that a plurality of sawblades could be mounted on the drive spline 11 depen~; ng on the lumber which is being cut and the desire~ of the operator.
Reference is now made to Figure 2 which illustrates the sawblade 10 mounted on the drive spline 11. The drive spline 11 and sawblade 10 have a common axis of rotation 21 and, under operation, the sawblade 10 rotates clockwise as seen by the arrows. A ~eries of inner driven surfaces 22 of sawblade 10 are complementary to outer drive rece~ses 23 of drive spline 11. The inner distance 24 of drive surface 22 is greater that the outer distance 25 such that if the sawblade contacts a foreign object such a spike in a tree being cut, the blade 10 will not be hurled from the drive spline 11 but will be ret~; ne~ by the drive spline 11 such that the operator may immediately terminate operation of the drive system.
More particularly, the out~ide circumference of the drive spline is indicated by first diameter dio and the inside diameter of the drive spline is indicated by second diameter d2i. The distance between dio and d2i is the distance between the outer diameter of the drive spline 11 and the most inwardly distance of the drive 5 recess 23.
First and second radials r1, r2 are drawn from the axis of rotation 21 to touch the ends of the drive recess 23 located most closely to axis 21. Third and 10 fourth radials r3, r4 are drawn from the axis of rotation 21 to touch the ends of the drive recess 23 located most remotely from axis 21. The angular distance between rl and r2 will be larger than the distance between r3 and r4 as can clearly be seen from Figures 2 and 3.
For example, in a first embodiment of the invention as illustrated in Figure 2, the distance between the ends of the drive recess 23 located closest to axis 21 is . 597 in. as illustrated. This di~tance is 20 obtained by drawing radials to each of the ends of the drive recess 23 and measuring the distance of . 597. A 60 degree angle is cut into the drive spline 23 and a surface is formed 90 degrees to the line defining the distance of . 597 in. which meets the 60 degree angle cut.
This surface defines the most advanced point of the radial rl and the most retarded point of radial r2.
It will be readily seen that a number of different configurations for the drive recesses 23 of drive spline 11 and the drive surfaces 22 of sawblade 10 could be used in order to achieve the benefits of the present invention. Reference is made, for example, to Figures 4A, 4B, 4C and 4D.
In Figure 4A, drive surfaces 30 take a somewhat partially convex configuration and in Figure 4B, drive 21~7899 surfaces 32 take on an appearance similar to the drive surfaces 22 of Figures 2 and 3 but extend inwardly a much greater distance. However, it remains the case that the angular distance e1 between the radials r1, r2 is less that the angular distance e2 between the radials r3, r4.
Figures 4C and 4D illustrate two further drive configurations according to further aspects of the invention. In each of these configurations, there is a drive surface 40, 41 which has an angle ~ relative to radial r3 which is greater than zero degrees. Thus, there will be a partial ret~;n;ng effect executed on the sawblade 43 by the forces executed between drive surfaces 41, 42 of the spline by the sawblade.
In Figure 5, replaceable drive surfaces 34 are located along removable inserts made of hardened steel material 35 ext~n~;ng axially along the spline 11, and being secured to the drive spline with bolts 36.
While specific embodiments of the invention have been described, such descriptions should be taken as illustrative of the invention only and not as limiting its scope as defined in accordance with the accompanying claims.
Claims (4)
1. A sawblade of circular configuration having an axis of rotation, an outer cutting edge and a plurality of inner driven surfaces defined by a first angular distance between a first and second radial, said first and second radials contacting each end of a respective one of said driven surfaces located most closely to said axis of rotation, and a second angular distance between a third and fourth radial, said third and fourth radials contacting each end of said respective one of said driven surfaces located most remotely from said axis of rotation, the angular distance between said first and second radials being greater than the angular distance between said third and fourth radials.
2. A drive spline of circular configuration having an axis of rotation, a plurality of outer drive recesses defined by a first angular distance between a first and second radial, said first and second radials contacting each end of a respective one of said drive recesses located most closely to said axis of rotation and a second angular distance between a third and fourth radial, said third and fourth radials contacting each end of a respective one of said drive recesses located most remotely from said axis of rotation, the angular distance between said first and second radial, being greater than the angular distance between said third and fourth radials.
3. A drive spline as in claim 2 wherein said drive recesses contain removable inserts which form drive surfaces on said spline.
4. A drive spline as in claim 3 wherein said removable inserts are made of hardened steel material.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2147899 CA2147899C (en) | 1995-04-26 | 1995-04-26 | Saw blade drive system |
| AU53943/96A AU706706B2 (en) | 1995-04-26 | 1996-04-26 | Saw blade drive system |
| AT96910874T ATE211666T1 (en) | 1995-04-26 | 1996-04-26 | SAW BLADE DRIVE DEVICE |
| PCT/CA1996/000266 WO1996033835A1 (en) | 1995-04-26 | 1996-04-26 | Saw blade drive system |
| DE69618452T DE69618452D1 (en) | 1995-04-26 | 1996-04-26 | BLADE DRIVE DEVICE |
| NZ305825A NZ305825A (en) | 1995-04-26 | 1996-04-26 | Saw blade drive arrangement has second point of inner surfaces positioned forwardly of first point |
| EP96910874A EP0822879B1 (en) | 1995-04-26 | 1996-04-26 | Saw blade drive system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2147899 CA2147899C (en) | 1995-04-26 | 1995-04-26 | Saw blade drive system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2147899A1 CA2147899A1 (en) | 1996-10-27 |
| CA2147899C true CA2147899C (en) | 1998-01-27 |
Family
ID=4155724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2147899 Expired - Fee Related CA2147899C (en) | 1995-04-26 | 1995-04-26 | Saw blade drive system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2147899C (en) |
-
1995
- 1995-04-26 CA CA 2147899 patent/CA2147899C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2147899A1 (en) | 1996-10-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |