CA1136962A - Chain saw - Google Patents
Chain sawInfo
- Publication number
- CA1136962A CA1136962A CA000401176A CA401176A CA1136962A CA 1136962 A CA1136962 A CA 1136962A CA 000401176 A CA000401176 A CA 000401176A CA 401176 A CA401176 A CA 401176A CA 1136962 A CA1136962 A CA 1136962A
- Authority
- CA
- Canada
- Prior art keywords
- guide
- drive sprocket
- sprocket
- chain
- guide bar
- 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
Links
Landscapes
- Sawing (AREA)
Abstract
ABSTRACT
The specification discloses a chain saw having a guide bar which is fastened to the frame of the chain saw so that most of the guide bar is out-ward of the chain saw frame (referred to as the forward portion), which portion is exposed for effective cutting, but with a mounting portion rearward of the frame and the drive sprocket of the chain saw for improved mounting and adjust-ment. The guide bar forms a part of a cassette which also includes a drive sprocket trapped in the bar and a saw chain extending around the sprocket ant the forward portion of the bar. A cover has clamping bosses clamping the bar to the frame, and an adjustment screw engaging the rearward end of the bar is mounted on the frame at the rear thereof so that it is readily accessible.
The specification discloses a chain saw having a guide bar which is fastened to the frame of the chain saw so that most of the guide bar is out-ward of the chain saw frame (referred to as the forward portion), which portion is exposed for effective cutting, but with a mounting portion rearward of the frame and the drive sprocket of the chain saw for improved mounting and adjust-ment. The guide bar forms a part of a cassette which also includes a drive sprocket trapped in the bar and a saw chain extending around the sprocket ant the forward portion of the bar. A cover has clamping bosses clamping the bar to the frame, and an adjustment screw engaging the rearward end of the bar is mounted on the frame at the rear thereof so that it is readily accessible.
Description
~3~
This is a division of our co-pending Canadian Patent Application No.
345,648 filed on February 14th, 1980.
This invention relates to an improved chain saw.
The invention provides an assembly including a saw chain, guide bar, and drive sprocket and further including means for mounting the assembly as a unit to a chain saw housing, the guide bar including a guide portion having guide slots along the sidc cdgos adapted to entrain therein the guide tangs of a saw chain, end guide means at one cnd of the guide portion for guiding the saw chain around said end from one side edge guide slot to the other side edge guide slot, a drive sprocket receiving portion extending from the guide bar portion on the end opposite the end guide means, a drive sprocket mounted in said drive sprocket receiving portion, the drive sprocket including sprocket teeth and a spindle provided with means for interengaging the drive sprocket to the drive shaft of a chain saw so that the sprocket can engage a loop of a saw chain entrained in the guide slots and end guide means of the guide bar portion and passing over the drive sprocket, the saw bar having a mounting portion extending past the drive sprocket portion and adapted to be fastened to the chain saw housing.
In the disclosed embodiment the guide bar includes two plates having first portions secured to a spacer plate to form a forwardly extended saw chain guiding portion and also has sprocket clearance portions extending around the drive sprocket. The mounting portion of the saw bar extends past the drive sprocket and rearward of the drive sprocket where it is clamped against the frame of the chain saw by a boss on a cover to form a cantilever mounting.
The invention will further be described by way of example only, with reference to the accompanying drawings, wherein:
Figure 1 is a perspective view of an improved chain saw forming one ~369~Z
embodiment of the invention;
Figure 2 is a fragmentary, vertical, sectional view of the chain saw of Figure l;
Figure 3 is a horizontal, sectional view taken along line 3-3 of Figure 2;
Figurc 4 is an enlarged, vertical, sectional, view taken along line 4-4 of Figure 2;
Figure 5 is an cnlarged, vertical, sectional view taken along line 5-5 of Figure 3, and, Figure 6 is an enlarged, vertical, sectional view taken along line 6-6 of Figure 5.
A chain saw 10 forming one embodiment of the invention includes a chain saw housing 12 having a motor housing 14, a handle 16, a head end frame or casting 18 secured by long screws to the motor housing and a cover 20. A
cassette 22 has a saw bar 24 guiding a saw chain 26 driven by a drive sprocket 28 mounted on a motor shaft 30. The cassette includes the saw chain and the sprocket, and is attachable to and detachable from the saw as a unit.
The saw bar 24 is clamped to the head end casting 18 both at the front and at the rear of the sprocket by boss portions 40 and 42 of the cover 20 and lands 44 and 46 of the casting 18. A wing nut 48 screwed onto a stud 52 clamps the cover to the casting. An ad~ustment screw 56 screwed into a nut 58 welded to the casting 18 engages the end of the saw bar 24 and adjusts it to a chain tightening position while the wing nuts are loosened. This adjustment mechanism gives a strong, positive tightening of the saw chain, and is conven-iently located at the rear of the chain saw. Also such adjustment is achieved at a remote point from the saw chain and thus offers the advantage of increased safety.
113t~962 The saw bar 24 includes outer plates 60 and 62 welded to a center plate 64 by spotwelds 66 and trap a nose sprocket 68 having an axle member 70 projecting through holes 72 in nose portion 74 of the plates 60 and 62. The saw chain is guided by guide edges 76 of the forward or chain guiding portions of plates 60 and 62, outcr edgo portions of the plates 60 and 62 forming a groove for the chain with the edge of thc centerplate. The rearward end portion of the saw bar is formed by tho two plates 60 and 62 welded together by spotwelds 78. The saw bar has a longitudinal guidc slot 80, which could be off-center to insurc that the cassotte cannot be rcversed. Also, a pair of lands 84 forms a guideway for longitudinal adjustment of the saw, the pair of lands 84 being rearward or to the left of the sprocket, as viewed in Figure 2.
The sprocket 28 is screwed onto an adapter 90 having a keying socket 92 receiving the shaft 30 of an electric motor of the saw. A capscrew 94 screwed into tapped bore 96 of the shaft locks the adapter to the shaft. Inter-mediate entrapping portions 98 and 100 of the plates 60 and 62 are spaced apart by bent portions 102, 104, 106 and 108 from each other to accommodate the drive sprocket and provide clearance for the portion of the saw chain passing around the sprocket. The portions 98 and 100 have longitudinal slots 110 and 112 in which boss portions 114 and 116 of the sprocket fit.
The saw bar 24 being clamped both rearwardly and forwardly at points spaced apart almost half the length o the saw bar is very securely held. Also since the saw bar is securedly held rearwardly thereof, the casting 18 and cover 20 need and do extend in the forward direction only slightly beyond the sprocket 28 so that a very long portion of the saw bar and saw chain are exposed and effective for sawing.
The saw bar 24, the saw chain 26 and the sprocket 28 are a unit and installed, removed and handled as such. The unit may be easily assembled in the saw and disassembled therefrom.
This is a division of our co-pending Canadian Patent Application No.
345,648 filed on February 14th, 1980.
This invention relates to an improved chain saw.
The invention provides an assembly including a saw chain, guide bar, and drive sprocket and further including means for mounting the assembly as a unit to a chain saw housing, the guide bar including a guide portion having guide slots along the sidc cdgos adapted to entrain therein the guide tangs of a saw chain, end guide means at one cnd of the guide portion for guiding the saw chain around said end from one side edge guide slot to the other side edge guide slot, a drive sprocket receiving portion extending from the guide bar portion on the end opposite the end guide means, a drive sprocket mounted in said drive sprocket receiving portion, the drive sprocket including sprocket teeth and a spindle provided with means for interengaging the drive sprocket to the drive shaft of a chain saw so that the sprocket can engage a loop of a saw chain entrained in the guide slots and end guide means of the guide bar portion and passing over the drive sprocket, the saw bar having a mounting portion extending past the drive sprocket portion and adapted to be fastened to the chain saw housing.
In the disclosed embodiment the guide bar includes two plates having first portions secured to a spacer plate to form a forwardly extended saw chain guiding portion and also has sprocket clearance portions extending around the drive sprocket. The mounting portion of the saw bar extends past the drive sprocket and rearward of the drive sprocket where it is clamped against the frame of the chain saw by a boss on a cover to form a cantilever mounting.
The invention will further be described by way of example only, with reference to the accompanying drawings, wherein:
Figure 1 is a perspective view of an improved chain saw forming one ~369~Z
embodiment of the invention;
Figure 2 is a fragmentary, vertical, sectional view of the chain saw of Figure l;
Figure 3 is a horizontal, sectional view taken along line 3-3 of Figure 2;
Figurc 4 is an enlarged, vertical, sectional, view taken along line 4-4 of Figure 2;
Figure 5 is an cnlarged, vertical, sectional view taken along line 5-5 of Figure 3, and, Figure 6 is an enlarged, vertical, sectional view taken along line 6-6 of Figure 5.
A chain saw 10 forming one embodiment of the invention includes a chain saw housing 12 having a motor housing 14, a handle 16, a head end frame or casting 18 secured by long screws to the motor housing and a cover 20. A
cassette 22 has a saw bar 24 guiding a saw chain 26 driven by a drive sprocket 28 mounted on a motor shaft 30. The cassette includes the saw chain and the sprocket, and is attachable to and detachable from the saw as a unit.
The saw bar 24 is clamped to the head end casting 18 both at the front and at the rear of the sprocket by boss portions 40 and 42 of the cover 20 and lands 44 and 46 of the casting 18. A wing nut 48 screwed onto a stud 52 clamps the cover to the casting. An ad~ustment screw 56 screwed into a nut 58 welded to the casting 18 engages the end of the saw bar 24 and adjusts it to a chain tightening position while the wing nuts are loosened. This adjustment mechanism gives a strong, positive tightening of the saw chain, and is conven-iently located at the rear of the chain saw. Also such adjustment is achieved at a remote point from the saw chain and thus offers the advantage of increased safety.
113t~962 The saw bar 24 includes outer plates 60 and 62 welded to a center plate 64 by spotwelds 66 and trap a nose sprocket 68 having an axle member 70 projecting through holes 72 in nose portion 74 of the plates 60 and 62. The saw chain is guided by guide edges 76 of the forward or chain guiding portions of plates 60 and 62, outcr edgo portions of the plates 60 and 62 forming a groove for the chain with the edge of thc centerplate. The rearward end portion of the saw bar is formed by tho two plates 60 and 62 welded together by spotwelds 78. The saw bar has a longitudinal guidc slot 80, which could be off-center to insurc that the cassotte cannot be rcversed. Also, a pair of lands 84 forms a guideway for longitudinal adjustment of the saw, the pair of lands 84 being rearward or to the left of the sprocket, as viewed in Figure 2.
The sprocket 28 is screwed onto an adapter 90 having a keying socket 92 receiving the shaft 30 of an electric motor of the saw. A capscrew 94 screwed into tapped bore 96 of the shaft locks the adapter to the shaft. Inter-mediate entrapping portions 98 and 100 of the plates 60 and 62 are spaced apart by bent portions 102, 104, 106 and 108 from each other to accommodate the drive sprocket and provide clearance for the portion of the saw chain passing around the sprocket. The portions 98 and 100 have longitudinal slots 110 and 112 in which boss portions 114 and 116 of the sprocket fit.
The saw bar 24 being clamped both rearwardly and forwardly at points spaced apart almost half the length o the saw bar is very securely held. Also since the saw bar is securedly held rearwardly thereof, the casting 18 and cover 20 need and do extend in the forward direction only slightly beyond the sprocket 28 so that a very long portion of the saw bar and saw chain are exposed and effective for sawing.
The saw bar 24, the saw chain 26 and the sprocket 28 are a unit and installed, removed and handled as such. The unit may be easily assembled in the saw and disassembled therefrom.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An assembly including a saw chain, guide bar, and drive sprocket and further including means for mounting the assembly as a unit to a chain saw housing, the guide bar including a guide portion having guide slots along the side edges adapted to entrain therein the guide tangs of a saw chain, end guide means at one end of the guide portion for guiding the saw chain around said end from one side edge guide slot to the other side edge guide slot, a drive sprocket receiving portion extending from the guide bar portion on the end opposite the end guide means, a drive sprocket mounted in said drive sprocket receiving portion, the drive sprocket including sprocket teeth and a spindle provided with means for interengaging the drive sprocket to the drive shaft of a chain saw so that the sprocket can engage a loop of a saw chain entrained in the guide slots and end guide means of the guide bar portion and passing over the drive sprocket, the saw bar having a mounting portion extending past the drive sprocket portion and adapted to be fastened to the chain saw housing.
2. An assembly according to claim 1 wherein said guide bar comprises a pair of plates that in said guide portion of the guide bar are so spaced apart as to form said guide slots and end guide means, wherein in the drive sprocket receiving portion said plates are spaced farther apart so as to receive the drive sprocket, and one of the plates has a slot therein through which a boss portion of the sprocket can extend.
3. An assembly according to claim 2 wherein the plates are in abutment with each other in the mounting portion of the guide bar.
4. An assembly according to claim 1, 2 or 3 including releasable means for clamping the mounting portion of the guide bar to the chain saw housing in a position in which the guide bar extends forwardly from the sprocket, and adjustment screw means mounted on the housing at the rear of the sprocket and engaging the mounting portion of the guide bar to hold the guide bar against rearward movement.
5. An assembly according to claim 1, wherein said drive sprocket receiving portion of the guide bar has sides spread apart for adjustably receiving said drive sprocket therebetween, said guide bar carrying said drive sprocket, and including means for releasably fastening said mounting portion rearwardly of said drive sprocket to said chain saw housing for disposing said drive sprocket in position for engaging the drive shaft while disposing said guide bar and chain longitudinally forward of said sprocket.
6. An assembly according to claim 1 wherein said guide bar includes a pair of side plates comprising said guide portion spaced a predetermined distance apart so as to form said guide slots and end guide means for said saw chain, said predetermined distance being less than the width of said saw chain, said guide plates having intermediate sprocket entrapping portions defining said drive sprocket receiving portion, said drive sprocket being carried by said intermediate portions, said intermediate portions being spaced apart sufficiently farther than said pre-determined distance and farther apart than the width of said saw chain for adjustably receiving said drive sprocket therebetween, the chain being entrained on the sprocket between said intermediate portions and around said forward guiding portions, said mounting portion of the guide bar located behind said intermediate portions from said guiding portions being con-structed for releasable mounting rearwardly of said drive sprocket on said chain saw housing for disposing said drive sprocket in engaging relation with the drive shaft while disposing said guide bar and chain longitudinally forward of said sprocket substantial-ly past said drive shaft.
7. An assembly according to claim 1 wherein the guide bar mounting portion is constructed for releasable mounting rearwardly of said drive sprocket on said chain saw housing for disposing said drive sprocket in engaging relation with the drive shaft while disposing said guide bar and chain longitudinally forward of said sprocket substantially past said housing, said mounting portion being provided with a longitudinal-ly elongated slot for receiving a fastener and said housing includ-ing a clamping cover for securing said guide bar to said housing by means of said fastener.
8. An assembly according to claim 7 further including adjustment screw means for mounting on said housing and adjustably engaging the mounting portion of said guide bar for urging said chain forwardly with respect to said sprocket.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000401176A CA1136962A (en) | 1979-02-26 | 1982-04-16 | Chain saw |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US015,111 | 1979-02-26 | ||
| US06/015,111 US4316327A (en) | 1979-02-26 | 1979-02-26 | Chain saw |
| CA345,648A CA1131101A (en) | 1979-02-26 | 1980-02-14 | Chain saw |
| CA000401176A CA1136962A (en) | 1979-02-26 | 1982-04-16 | Chain saw |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1136962A true CA1136962A (en) | 1982-12-07 |
Family
ID=27166586
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000401176A Expired CA1136962A (en) | 1979-02-26 | 1982-04-16 | Chain saw |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1136962A (en) |
-
1982
- 1982-04-16 CA CA000401176A patent/CA1136962A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |