CA2477180A1 - Pentagon shank rotary mower blade bolt - Google Patents
Pentagon shank rotary mower blade bolt Download PDFInfo
- Publication number
- CA2477180A1 CA2477180A1 CA002477180A CA2477180A CA2477180A1 CA 2477180 A1 CA2477180 A1 CA 2477180A1 CA 002477180 A CA002477180 A CA 002477180A CA 2477180 A CA2477180 A CA 2477180A CA 2477180 A1 CA2477180 A1 CA 2477180A1
- Authority
- CA
- Canada
- Prior art keywords
- bolt
- blade
- carrier
- section
- shank
- 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.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01D—HARVESTING; MOWING
- A01D34/00—Mowers; Mowing apparatus of harvesters
- A01D34/01—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus
- A01D34/412—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters
- A01D34/63—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters having cutters rotating about a vertical axis
- A01D34/73—Cutting apparatus
- A01D34/733—Cutting-blade mounting means
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01D—HARVESTING; MOWING
- A01D34/00—Mowers; Mowing apparatus of harvesters
- A01D34/01—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus
- A01D34/412—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters
- A01D34/63—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters having cutters rotating about a vertical axis
- A01D34/73—Cutting apparatus
- A01D34/736—Flail type
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Environmental Sciences (AREA)
- Harvester Elements (AREA)
Abstract
A blade bolt for a rotary mower has a head for supporting the blade, a shoulder on which the blade rotates and a shank that passes through the blade carrier. a nut is threaded onto a terminal threaded section of the bolt to capture the carrier between the shoulder and the nut. The shank has a pentagonal cross section to prevent rotation of the bolt in a mating pentagonal carrier bolt hole. An anti-rotation keying system for a blade bolt mounting a mower blade on a blade carrier of a rotary mower: includes the carrier bolt hole of pentagonal shape and the pentagonal cross section shank section of the blade bolt to engage non-rotatably in the carrier bolt hole.
Description
PENTAGON SHANK ROTARY MOWER BLADE BOLT
FIELD OF THE INVENTION
The present inven~on relates to blade bolts used to retain mpwer blades onto the blade carrier of a mower.
background In a rotary mower, a blade bolt is used to retain free swinging rotary mower blades onto the blade carrier of the rotary mower. The conventional blade bolt has and a pin with shoulder, shank and threaded sections.
Rotary mower blade bolts have been in erse since the 1950's when free swinging mower blades were first used. Regular hex bolts were used with a bushing to act as a shoulder for the blade bolt to ride on. During the 1960's, a one piece blade bolt was developed fio retain the free swinging blade on the blade carrier.
This blade bolt incorporated a shoulder on the pfn near the head. A key was forged into the round shank section of this bolt to keep it from turning when a retaining nut was tightened on the bolt. The problem that arose with this blade bolt is that the key can easily be broken off, allowing the bolt to rotate in the blade carrier hole.
This makes the blade bolt unusable.
In the 1970's a blade bolt with a square shank, similar to a carriage bolt, was developed to prevent the bolt from rotating in the blade carrier. The square shoulders solved the problem of the key breaking off. However, stress concentrations at the corners of the square hole in the blade carrier caused cracking and failure of the blade carrier.
Hexagonal shank blade bolts are also commonly used. The hexagonal hole in the blade carrier is not as prone to cracking at the comers as the square hole.
The hexagon shank is more robust than the key, but the relatively flat 120° corners will allow the bolt to tum slightly and jam, making removal difficult_ if high torque is applied when tightEning a nut onto the bolt and in severe field conditions, the corners may "strip " in the hole. This allows the bolt to tum freely in the carrier mounting hale..
This is analogous to the "stripping" of the heads of hex bolts, where the corners between the flats become rounded.
The hex shank requires a closer tolerance fit with the hole than the square shank, requiring closer tolerance manufacturing, and making installation of the bolt more difficult. On the other hand, if the square shank bolt is too loose a fit In the bolt hole, the risk of crack initiation and propagation is ir:creased.
SUMMAF~Y
According to one aspect of the present invention there is provided a blade bolt for a rotary mower comprising:
a head; and a shank section having a pentagonal shape in cross section.
The pin will normally include a shoulder section adjacent the shank section, this shoulder section being of circular cross section to engage rotatably in a circular bolt hole in the blade and a threaded section at the end of the bolt.
A nut threaded onto the threaded section holds the bolt in place.
The head and shoulder configuration retains the free swinging mower blade and allows it to swing freely when the bolt is firmly attached. The pentagon shape of the shank has been found satisfactory in preventing the blade bolt from turning in the blade carrier while the blade bolt nut is being tightened while the pentagonal bolt hole in the carrier is less prone to the promotion of the cracking and failure that characterized prior art square holes.
According to another aspect of the present invention there is provided an anti-rotation keying system for a blade bolt mounting a mower blade on a blade carrier of a rotary mower, said system comprisingr a carrier bolt hole of pentagonal shape through the blade carrier; and a blade bolt having a head at one end of the bolt and a shank section of pentagonal cross section to engage non-rotatably in the carrier bolt hole.
The blade will conventionally have a blade bolt hole of circular shape to engage rotatably on a cylindrical shoulder section of the bait between the head and the shank section.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate certain prior art blade bolts and an exemplary embodiment of the present invention:
Figure 1 is a bottom view of a blade assembly;
Figure 2 is a cross section along sine II-II of Figure 1;
Figure 3 is an isometric view of a prior art bolt with a keyed shank;
Figure 4 is a section showing the engagement of the bolt of Figure 3 in a mating bolt hole;
Figure 5 is an isometric view of a prior art bolt with a square shank;
Figure 6 is a section showing the engagement of the bolt of Figure 5 in a mating bolt hole;
Figure 7 is a section showing the engagement of a bolt with an hexagonal shank in a mating bolt hole;
Figure 8 is an isometric view of a bolt according to the present invention;
Figure 9 is a section along line IX-IX of Figure 2, showing the engagement of the bolt of Figure 8 in a mating bolt hole;
Figure 10 is a side view of the bolt of Figure 8;
Figure 11 is a side view of the bolt of Figure 8, orthogonal to the view in Figure 10;
Figure 12 is an end view of the bolt; and Figure 13 is an opposite end view of the bolt.
Referring to the accompanying drawings and particularly Figure 1, there is illustrated a blade assembly 70 for a rotary mower. The assembly includes a disc like carrier 12 mounted on a drive shaft (not illustrated)_ Two blades 14 are mounted at diametrically opposite positions on the carrier by respective blade bolts 16.
As illustrated in Figure 2, the bolt 16 has a head 18 supporting the blade 14_ A shoulder 20 adjacent the head ~xtends through a mounting hole 22 in the blade. The shoulder abuts the face of the carrier and provides a journal on which the blade 14 can rotate freely. A Shank section 24 of the bolt passes through a bolt hole 26 (n the carrier 12. On the side of the carrier opposite the blade 94, a threaded section 28 of the bolt carries a nut 30 which engages the carrier to clamp it against the shoulder 20.
In one form of prior art bolt 32, illustrated in Figures 3 and 4, a key 34 is ~ forged into the round shank 24 to engage in a mating keyway 3B in the carrier bolt hole 26. The key is to keep the bolt from turning when the retaining nut 30 was tightened on the bolt. The problem with this blade bolt is that the key can easily be broken off, allowing the bolt to rotate In the blade carrier hole. This makes the blade bolt unusable.
Another prior art blade bolt is illustrated in Figures 5 and 6. This blade bolt 40 has a square shank 42 to prevent the bolt from rotating in a square blade mounting hole 44 In the carrier. While the square shank solves the problem of the key breaking off, the 90° comers of the square hole in the blade carrier are stress concentrators that can develop cracks, such as crack 45, causing fracture of the blade carrier.
A third prior art blade bolt (Figure 7) has an hexagonal shank 48 to ~4-engage in an hexagonal bolt hole 50. The hexagonal hole is not as prone to cracking at the corners as the square hole. The hexagon shank is more robust then the key, but the relatively flat 120° corners will allow the bolt to tum slightly and jam, making removal difficuk. If high torque is applied when tightening a nut onto the bolt and in severe field conditions, the com~rs may "strip " in the hole. This allows the bolt to turn freely In the carrier mounting hole.
The hex shank requires a Goser tolerance fit with the hole than the square shank, requiring closer tolerance manufacturing, and making installation of the bolt mere difficult. On the other hand, if the square shank bolt is too loose a ft in the bolt hole, the risk of crack initiation and propagation is increased.
A bolt 54 according to th~ present invention is illustrated in Figures 8 through 13. The shaft 56 has a pentagonal sectional shape to mate in s bolt hole 58 In the carrier that is likewise pentagonal. This shank form is able to maintain solid contact with hole in the blade carrier. The 108° corners of the bolt hole reduce the development of cracks in the blade bolt hole in the blade carrier.
While one embodiment of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.
_5_
FIELD OF THE INVENTION
The present inven~on relates to blade bolts used to retain mpwer blades onto the blade carrier of a mower.
background In a rotary mower, a blade bolt is used to retain free swinging rotary mower blades onto the blade carrier of the rotary mower. The conventional blade bolt has and a pin with shoulder, shank and threaded sections.
Rotary mower blade bolts have been in erse since the 1950's when free swinging mower blades were first used. Regular hex bolts were used with a bushing to act as a shoulder for the blade bolt to ride on. During the 1960's, a one piece blade bolt was developed fio retain the free swinging blade on the blade carrier.
This blade bolt incorporated a shoulder on the pfn near the head. A key was forged into the round shank section of this bolt to keep it from turning when a retaining nut was tightened on the bolt. The problem that arose with this blade bolt is that the key can easily be broken off, allowing the bolt to rotate in the blade carrier hole.
This makes the blade bolt unusable.
In the 1970's a blade bolt with a square shank, similar to a carriage bolt, was developed to prevent the bolt from rotating in the blade carrier. The square shoulders solved the problem of the key breaking off. However, stress concentrations at the corners of the square hole in the blade carrier caused cracking and failure of the blade carrier.
Hexagonal shank blade bolts are also commonly used. The hexagonal hole in the blade carrier is not as prone to cracking at the comers as the square hole.
The hexagon shank is more robust than the key, but the relatively flat 120° corners will allow the bolt to tum slightly and jam, making removal difficult_ if high torque is applied when tightEning a nut onto the bolt and in severe field conditions, the corners may "strip " in the hole. This allows the bolt to tum freely in the carrier mounting hale..
This is analogous to the "stripping" of the heads of hex bolts, where the corners between the flats become rounded.
The hex shank requires a closer tolerance fit with the hole than the square shank, requiring closer tolerance manufacturing, and making installation of the bolt more difficult. On the other hand, if the square shank bolt is too loose a fit In the bolt hole, the risk of crack initiation and propagation is ir:creased.
SUMMAF~Y
According to one aspect of the present invention there is provided a blade bolt for a rotary mower comprising:
a head; and a shank section having a pentagonal shape in cross section.
The pin will normally include a shoulder section adjacent the shank section, this shoulder section being of circular cross section to engage rotatably in a circular bolt hole in the blade and a threaded section at the end of the bolt.
A nut threaded onto the threaded section holds the bolt in place.
The head and shoulder configuration retains the free swinging mower blade and allows it to swing freely when the bolt is firmly attached. The pentagon shape of the shank has been found satisfactory in preventing the blade bolt from turning in the blade carrier while the blade bolt nut is being tightened while the pentagonal bolt hole in the carrier is less prone to the promotion of the cracking and failure that characterized prior art square holes.
According to another aspect of the present invention there is provided an anti-rotation keying system for a blade bolt mounting a mower blade on a blade carrier of a rotary mower, said system comprisingr a carrier bolt hole of pentagonal shape through the blade carrier; and a blade bolt having a head at one end of the bolt and a shank section of pentagonal cross section to engage non-rotatably in the carrier bolt hole.
The blade will conventionally have a blade bolt hole of circular shape to engage rotatably on a cylindrical shoulder section of the bait between the head and the shank section.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate certain prior art blade bolts and an exemplary embodiment of the present invention:
Figure 1 is a bottom view of a blade assembly;
Figure 2 is a cross section along sine II-II of Figure 1;
Figure 3 is an isometric view of a prior art bolt with a keyed shank;
Figure 4 is a section showing the engagement of the bolt of Figure 3 in a mating bolt hole;
Figure 5 is an isometric view of a prior art bolt with a square shank;
Figure 6 is a section showing the engagement of the bolt of Figure 5 in a mating bolt hole;
Figure 7 is a section showing the engagement of a bolt with an hexagonal shank in a mating bolt hole;
Figure 8 is an isometric view of a bolt according to the present invention;
Figure 9 is a section along line IX-IX of Figure 2, showing the engagement of the bolt of Figure 8 in a mating bolt hole;
Figure 10 is a side view of the bolt of Figure 8;
Figure 11 is a side view of the bolt of Figure 8, orthogonal to the view in Figure 10;
Figure 12 is an end view of the bolt; and Figure 13 is an opposite end view of the bolt.
Referring to the accompanying drawings and particularly Figure 1, there is illustrated a blade assembly 70 for a rotary mower. The assembly includes a disc like carrier 12 mounted on a drive shaft (not illustrated)_ Two blades 14 are mounted at diametrically opposite positions on the carrier by respective blade bolts 16.
As illustrated in Figure 2, the bolt 16 has a head 18 supporting the blade 14_ A shoulder 20 adjacent the head ~xtends through a mounting hole 22 in the blade. The shoulder abuts the face of the carrier and provides a journal on which the blade 14 can rotate freely. A Shank section 24 of the bolt passes through a bolt hole 26 (n the carrier 12. On the side of the carrier opposite the blade 94, a threaded section 28 of the bolt carries a nut 30 which engages the carrier to clamp it against the shoulder 20.
In one form of prior art bolt 32, illustrated in Figures 3 and 4, a key 34 is ~ forged into the round shank 24 to engage in a mating keyway 3B in the carrier bolt hole 26. The key is to keep the bolt from turning when the retaining nut 30 was tightened on the bolt. The problem with this blade bolt is that the key can easily be broken off, allowing the bolt to rotate In the blade carrier hole. This makes the blade bolt unusable.
Another prior art blade bolt is illustrated in Figures 5 and 6. This blade bolt 40 has a square shank 42 to prevent the bolt from rotating in a square blade mounting hole 44 In the carrier. While the square shank solves the problem of the key breaking off, the 90° comers of the square hole in the blade carrier are stress concentrators that can develop cracks, such as crack 45, causing fracture of the blade carrier.
A third prior art blade bolt (Figure 7) has an hexagonal shank 48 to ~4-engage in an hexagonal bolt hole 50. The hexagonal hole is not as prone to cracking at the corners as the square hole. The hexagon shank is more robust then the key, but the relatively flat 120° corners will allow the bolt to tum slightly and jam, making removal difficuk. If high torque is applied when tightening a nut onto the bolt and in severe field conditions, the com~rs may "strip " in the hole. This allows the bolt to turn freely In the carrier mounting hole.
The hex shank requires a Goser tolerance fit with the hole than the square shank, requiring closer tolerance manufacturing, and making installation of the bolt mere difficult. On the other hand, if the square shank bolt is too loose a ft in the bolt hole, the risk of crack initiation and propagation is increased.
A bolt 54 according to th~ present invention is illustrated in Figures 8 through 13. The shaft 56 has a pentagonal sectional shape to mate in s bolt hole 58 In the carrier that is likewise pentagonal. This shank form is able to maintain solid contact with hole in the blade carrier. The 108° corners of the bolt hole reduce the development of cracks in the blade bolt hole in the blade carrier.
While one embodiment of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.
_5_
Claims (4)
1. A blade bolt for a rotary mower comprising:
a head; and a shank section having a pentagonal shape in cross section.
a head; and a shank section having a pentagonal shape in cross section.
2. A blade bolt according to Claim 1 further comprising a shoulder section between the shank section and the head.
3. An anti-rotation keying system for a blade bolt mounting a mower blade on a blade carrier of a rotary mower, said system comprising:
a carrier bolt hole of pontagonal shape through the blade carrier; and a blade bolt having a head at one end of the bolt and a shank section of pentagonal cross section to engage non-rotatably in the carrier bolt hole.
a carrier bolt hole of pontagonal shape through the blade carrier; and a blade bolt having a head at one end of the bolt and a shank section of pentagonal cross section to engage non-rotatably in the carrier bolt hole.
4. A keying system according to Claim 3 wherein the blade has a blade bolt hole of circular shape and the pin of the bolt has a shoulder section between the head and the shank section, the shoulder section being of circular cross section to engage rotatably in the blade bolt hole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002477180A CA2477180A1 (en) | 2004-08-11 | 2004-08-11 | Pentagon shank rotary mower blade bolt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002477180A CA2477180A1 (en) | 2004-08-11 | 2004-08-11 | Pentagon shank rotary mower blade bolt |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2477180A1 true CA2477180A1 (en) | 2006-02-11 |
Family
ID=35851890
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002477180A Abandoned CA2477180A1 (en) | 2004-08-11 | 2004-08-11 | Pentagon shank rotary mower blade bolt |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2477180A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2165589A1 (en) * | 2008-09-22 | 2010-03-24 | Deere & Company | Knife holding mechanism |
| US7814735B2 (en) | 2007-12-19 | 2010-10-19 | Highline Manufacturing Ltd. | Bolt for attaching a rotary mower blade |
| WO2011153090A1 (en) * | 2010-06-03 | 2011-12-08 | Preformed Line Products Company | Module clamp and fastener apparatus |
| GB2554654A (en) * | 2016-09-30 | 2018-04-11 | Redwood Global Ltd | A bolt |
-
2004
- 2004-08-11 CA CA002477180A patent/CA2477180A1/en not_active Abandoned
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7814735B2 (en) | 2007-12-19 | 2010-10-19 | Highline Manufacturing Ltd. | Bolt for attaching a rotary mower blade |
| EP2165589A1 (en) * | 2008-09-22 | 2010-03-24 | Deere & Company | Knife holding mechanism |
| US7703268B2 (en) | 2008-09-22 | 2010-04-27 | Deere & Company | Rotary cutter bar mechanism and blade pin coupling |
| WO2011153090A1 (en) * | 2010-06-03 | 2011-12-08 | Preformed Line Products Company | Module clamp and fastener apparatus |
| GB2493469A (en) * | 2010-06-03 | 2013-02-06 | Preformed Line Products Co | Module clamp and fastener apparatus |
| US8702335B2 (en) | 2010-06-03 | 2014-04-22 | Preformed Line Products Company | Module clamp and fastener apparatus |
| GB2493469B (en) * | 2010-06-03 | 2014-10-22 | Preformed Line Products Co | Module clamp and fastener apparatus |
| GB2554654A (en) * | 2016-09-30 | 2018-04-11 | Redwood Global Ltd | A bolt |
| GB2557405A (en) * | 2016-09-30 | 2018-06-20 | Redwood Global Ltd | A bolt |
| GB2557405B (en) * | 2016-09-30 | 2019-04-24 | Redwood Global Ltd | A flywheel blade fixing apparatus |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |