GB2554654A

GB2554654A - A bolt

Info

Publication number: GB2554654A
Application number: GB1616641.5A
Authority: GB
Inventors: Brian Evans Howard
Original assignee: Redwood Global Ltd
Current assignee: Redwood Global Ltd
Priority date: 2016-09-30
Filing date: 2016-09-30
Publication date: 2018-04-11
Also published as: GB201715877D0; GB201616641D0; GB2557405A; GB2557405B

Abstract

A bolt 100 for a flywheel mounted blade where in the bolt comprises a head section 110; and a shank 150 extending from the head section, wherein said shank comprises a first section 120 comprising a circular cross section, a second section 130 comprising a geometric, oblong or oval cross section, and a third section 140 comprising a thread for a nut. The head section may be frustoconical in shape and have a planar face 111. The three sections on the shank may be adjacent to one another. The geometric shaped cross section may comprise of any known shape, and the edges may have chamfered or rounded corners. The bolt may comprise a first cross sectional diameter which is greater than or equal to the longest cross sectional dimension of the second section. The bolt may be part of a kit of parts comprising blade carrier having an aperture to engage with the second section of the bolt, a blade comprising an aperture to engage with the first section of said bolt, a bolt and a nut to engage the thread of the third section.

Description

(54) Title of the Invention: A bolt Abstract Title: A bolt (57) A bolt 100 for a flywheel mounted blade where in the bolt comprises a head section 110; and a shank 150 extending from the head section, wherein said shank comprises a first section 120 comprising a circular cross section, a second section 130 comprising a geometric, oblong or oval cross section, and a third section 140 comprising a thread for a nut. The head section may be frustoconical in shape and have a planar face 111. The three sections on the shank may be adjacent to one another. The geometric shaped cross section may comprise of any known shape, and the edges may have chamfered or rounded corners. The bolt may comprise a first cross sectional diameter which is greater than or equal to the longest cross sectional dimension of the second section. The bolt may be part of a kit of parts comprising blade carrier having an aperture to engage with the second section of the bolt, a blade comprising an aperture to engage with the first section of said bolt, a bolt and a nut to engage the thread of the third section.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

1/3

10 16

141

FIG. 1

2/3

10 16

FIG. 2

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10 16

FIG. 3

A Bolt

Field of the Invention

The present invention relates to a bolt, more specifically a bolt for a flywheel mounted blade, and more specifically still to a bolt for a flywheel blade comprising a shank that comprises a geometric or oval cross section.

Background to the Invention

In chippers, cutters and other vegetation shredding equipment, blades may be used to break down bulk vegetation in to pieces sized for disposal. In any such machine, to ensure an efficient chipping process, a plurality of blades is typically mounted on a rotating flywheel. Here, each blade is affixed to a circular flywheel such that its cutting edge lies parallel to a radius of that same flywheel. As such, any rotation of the flywheel results in the concomitant rotation of the blades and the reduction of all contacted vegetation. Typically, the rotation of the flywheel is powered by a petrol or diesel motor. In this way, any vegetation may be reliably chipped at a remote location, distant from any source of electrical power, although the use of a battery powered chipper remains a possibility.

Whilst any such chipper may initially provide a satisfactory solution to the reduction and disposal of vegetation, the nature of the material for disposal may rapidly degrade the performance of the blades. Any vegetation reduced by the chipper is unlikely to be completely free of soil and stones, and the vegetation itself is likely to include relatively tough materials. Therefore, it is unsurprising any blades used within the chipper become blunt, worn and unusable well within the expected lifetime of the chipper as a whole.

To combat this blunting of the blades, modern chipping machines usually include removable blades. Here, the blades are most commonly securely fixed to the flywheel using bolts, allowing the blades to be removed and replaced where required.

Where a bolt is used to affix a blade to the flywheel, both the blade itself and the flywheel typically include a matching pattern of apertures. Each aperture in the blade is then overlaid onto a corresponding aperture in the flywheel, and a bolt inserted through both the blade and the flywheel via the aligned apertures. The complete passage of the bolt through the apertures is prevent by an enlarged head at one end of the bolt, this head sized such that it is unable to pass through the aperture in either the blade or the flywheel.

After insertion of the bolt into the apertures, a nut is placed on the end of the bolt distal from the head. This nut may be secured on to the bolt via a screw thread. Where a screw thread is used, the bolt and nut may be tightened using an indentation in the head of the bolt suitable for engagement with a screwdriver, Allen key or torx fitting, whilst a spanner, ratchet or similar is used to hold the nut in place. In this manner, the nut and bolt may be tightened to hold the blade in position on the flywheel. Alternatively, the bolt may screw directly into a thread located within the aperture on the flywheel.

Whilst such a solution allows worn, damaged and blunted blades to be removed from the flywheel, the use of bolts is not without issue. During the operation of the chipper, debris from the vegetation reduced is propelled over all surfaces in the vicinity of the cutting blades and, as a result, becomes trapped in the indentation located in the head of the bolt. In such a situation, it becomes more difficult for the user to remove the blade, and the overall replacement process may become very time consuming.

Additionally, this effect may be compounded if not all debris is removed from the indentation before removal of the bolt is attempted, and the indentation becomes misshapen or rounded off. Any deformation of the indentation further increases the difficulty of removing a blade. Finally, if the screw thread is located within the flywheel aperture itself, debris may enter this aperture and damage the screw threads during the affixation or removal of a blade, potentially resulting in the need to replace the flywheel, a relatively costly undertaking.

Summary of the Invention

According to a first aspect of the present invention, there is provided a bolt for a flywheel mounted blade, said bolt comprising; a head section, and a shank extending from the head section, wherein said shank comprises a first section comprising a circular cross section, a second section comprising a geometric, oblong or oval cross section, and a third section comprising a thread for engaging a nut.

In this way, there is provided a bolt capable of connecting a blade to a flywheel without the use of a screwdriver, Allen key or torx fitting. During use, the bolt is inserted through corresponding apertures in the blades and the flywheel, wherein the geometric or oval second section of the bolt engages with a specifically sized aperture in the flywheel to prevent the rotation of the bolt. A nut may then be screwed on to the third section of the bolt to hold the bolt, and thus the blade, in place. Additionally, such a bolt enables the installation of the bolt with one hand, whilst the second hand holds the blade, increasing the safety of blade installation.

Preferably, the head section is frustoconical. Preferably, the head section is tapered.

Preferably, the first section is adjacent to the head section. Preferably the second section is adjacent to the first section. Preferably the third section is adjacent to the second section. Preferably, the third section is proximal to a distal end of the shank. Preferably, the head section, first section, second section and third section are positioned in sequence from the proximal to distal end of the bolt.

Preferably a first face of the head section that opposes the shank is substantially planar. Preferably, the first face of the head section is substantially planar across its entire surface. Alternatively, it may be preferable for the first face to be curved, more preferably smoothly curved, still more preferably a spherical cap. Alternatively, the first face may be a segment of a sphere.

Preferably, the cross sectional diameter of the first section is greater than or equal to the longest cross sectional dimension of the second section.

Preferably, the second section comprises a greater length of shank than the first section. More preferably, the second section is two to eight times longer than the first section. Still more preferably, the second section is 4 to 6 times the length of the first section. Most preferably, the second section is five times the length of the first section.

Preferably, the second section comprises a geometric cross section with chamfered corners. Preferably the second section comprises a cross section with rounded corners. More preferably, the second section comprises a cross section with rounded corners, wherein each corner has a constant radius of curvature. Still more preferably, the second section comprises a plurality of rounded corners, each rounded corner having the same radius of curvature.

Preferably, the second section comprises a rectangular cross section. More preferably, the second section comprises a square cross section. Alternatively, the second section comprises a triangular, rhomboid, trapezoid, pentagonal, hexagonal, heptagonal, octagonal, nonagonal, decagonal or dodecagonal cross section. Alternatively the second section comprises an elliptical cross section.

Preferably, the bolt comprises carbon steel. Preferably, the bolt is plated, and the plating comprises zinc. Preferably, the plating comprises nickel. Preferably the plating comprises both zinc and nickel.

Preferably the bolt is a blade fixing bolt.

According to a second aspect ofthe invention, there is provided a kit of parts comprising, a blade carrier, and a bolt as previously described, wherein the blade carrier comprises at least one aperture sized to engage the second section ofthe bolt.

Preferably, the kit of parts further comprises a blade, wherein the blades comprises at least one aperture sized to engage the first section or head section ofthe bolt.

Preferably, the kit of parts further comprises a nut, wherein the nut is sized to engage the thread on the third section ofthe bolt.

Detailed Description

An embodiment ofthe present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is an isometric view of a bolt in accordance with the present invention;

Figure 2 is a side view of a bolt in accordance with the present invention; and

Figure 3 is a cross sectional view of a bolt in accordance with the present invention.

Referring to Figure 1 ofthe drawings, there is shown a bolt 100 in accordance with the present invention. Here, the bolt 100 comprises a head section 110, a first section 120, a second section 130 and a third section 140. The first section 120, second section 130 and third section 140 together form a shank 150 that extends from the head portion 110 along a longitudinal axis of the bolt 100. The bolt 100 is made from a carbon steel, plated in zinc to reduce corrosion.

Referring to each section in turn, the head section 110 is frustoconical in shape, tapering down from a first face 111 at a proximal end ofthe bolt to the junction ofthe head section 110 and the first section 120. As shown in Figure 1, this taper is smooth and linear, resulting in a consistent and constant reduction of the cross section of the head portion 110, where this cross section is taken at a plane perpendicular to the longitudinal axis of the bolt 100. Such a taper here occurs over a distance of 7.5 mm, resulting in the sides of the head piece 110 being angled at 45° to the longitudinal axis of the bolt 100.

The first face 111 is located at the proximal end of the bolt 100, and is substantially planar, the surface of the face lying in a plane perpendicular to the longitudinal axis of the bolt 100. Figure 1 depicts the entirety of the surface of the first face 111 lying in a plane perpendicular to the longitudinal axis of the bolt 100.

The distal end of the head section 110 is connected to the first section 120. The first section has a diameter that is smaller than that of the head section 100, and has a generally circular cross section where this cross section is taken at a plane perpendicular to the longitudinal axis of the bolt 100. The first section 120 extends for a relatively short distance along the longitudinal axis of the bolt 100, here for around 3 mm. Additionally, the first section 120 has a constant cross section throughout, forming a cylinder.

The distal end of the first section 120, is connected to the second section 130. In Figure 1, the second section 130 is illustrated as having a geometric cross section where this cross section is taken at a plane perpendicular to the longitudinal axis of the bolt 100. More specifically, the cross section of the second section 130 is a square with chamfered or rounded comers, although other geometric shapes, ovals, ellipses and oblongs are also envisaged.

The edges of the second section 130 that lie parallel to the longitudinal axis of the bolt 100 are rounded. The edges are rounded to form a curve with a constant radius of curvature, to form a second section 130 with a fourfold axis of rotational symmetry, wherein the longitudinal axis of the bolt 100 forms the axis of symmetry.

The second section 130 has a longest cross sectional dimension of equal length to the cross sectional diameter of the first section 120. Additionally, the second section 130 extends for 15 mm along the longitudinal axis of the bolt 100. As such, the second section 130 is around five times the length of the first section 120.

At its distal end, the second section 130 tapers and connects to the third section 140. This tapered section extends for around 4 mm along the longitudinal axis of the bolt 100, and the third section 140 extends for around 16 mm along the longitudinal axis of the bolt. The third section 140 has a circular cross section where this cross section is taken at a plane perpendicular to the longitudinal axis of the bolt 100. Additionally, a screw thread extends around the outer surface of the third section 140, such that the third section 140 is capable of engaging with bolt or other threaded fastening means. The edge of the bolt 100 at the distal end of the third section 140 is also chamfered or rounded, smoothing the transition from the side of the third section 140 to the distal face 141 of the bolt 100.

The aforementioned features of this embodiment of the invention are also illustrated in Figure 2. Figure 2 depicts the bolt 100 from a side view, illustrating the head section 110 and the formation of the shank 150 from the first section 120, the second section 130 and the third section 140. The relative dimensions of each section are depicted, with the greater diameter of the head section 110, and its taper into the first section 120, clearly represented. Figure 2 also illustrates that the third section 140 has a smaller cross sectional diameter than the first section 120, where these cross sections are taken at a plane perpendicular to the longitudinal axis of the bolt 100

The bolt 100 may be further viewed in Figure 3, where a cross section along the longitudinal axis of the bolt 100 is reproduced. Here it can be seen the bolt has an axis of rotational symmetry along the centre of its longitudinal axis, shown by line 160. The shank 150 and the head section 110 are again depicted.

In use, the bolt 100 affixes a blade to a blade carrier on a flywheel in a wood chipping machine. Here, both the blade and the blade carrier contain a matching pattern of apertures, the apertures in the blade being circular and the apertures in the blade carrier being sized to receive and correspond to the second section 130 of the bolt 100. To install a bolt 100, an aperture in the blade is overlaid onto a corresponding aperture in the blade carrier, and a bolt inserted through both the blade and the blade carrier via the aligned apertures.

After insertion, when the first section 120 and the head section 110 abut the blade, they act as locators for the blade. The bolt is positioned such it cannot cannot rotate around its longitudinal axis as the second section 130 is located within the aperture of the blade carrier and so acts as locator in the blade carrier. The complimentary, interlocking shapes of the second section 130 and the aperture in the blade carrier prevent any rotation and create and original bolt design.

The third section 140 protrudes from the blade carrier such that the screw thread is accessible. To complete the installation of the bolt 100, a nut is threaded on to the screw thread and tightened to maintain the bolt 100 in position, to ensure the head section 110 and the first section 120 remain abutting the blade, and that the second section 130 remains within the aperture of the blade carrier. When removal of the blade is required, this nut is loosened, and the bolt 100 removed from both apertures. Tightening and loosening of the nut may be undertaken one handed, the user’s second hand used to hold the blade to prevent its fall, increasing the safety of blade installation and removal. In this embodiment ofthe invention the head 110 and first section 120 along with second section 130 can be considered to provide the innovative locating function. The overall positioning and locking is provided by the complimentary, interlocking shapes of the second section 130 and the aperture in the blade carrier which prevent any rotation between the blade and the blade carrier.

Claims

1. A bolt for a flywheel mounted blade, said bolt comprising; a head section, and a shank extending from the head section, wherein said shank comprises a first section comprising a circular cross section, a second section comprising a geometric, oblong or oval cross section, and a third section comprising a thread for engaging a nut.

2. A bolt according to claim 1, wherein said head section is frustoconical.

3. A bolt according to claim 1 or claim 2, wherein said first section is adjacent to said head section.

4. A bolt according to claim 3, wherein said second section is adjacent to said first section.

5. A bolt according to claim 4, wherein said third section is adjacent to said second section.

6. A bolt according to any preceding claim, wherein said third section is proximal to a distal end of said shank.

7. A bolt according to any preceding claim, wherein a first face of said head section that opposes said shank is substantially planar.

8. A bolt according to any preceding claim, wherein the cross sectional diameter of said first section is greater than or equal to the longest cross sectional dimension of said second section.

9. A bolt according to any preceding claim, wherein said second section comprises a greater length of said shank than said first section.

10. A bolt according to any preceding claim, wherein said second section comprises a geometric cross section with chamfered or rounded corners.

11. A bolt according to any preceding claim, wherein said second section comprises a square cross section.

12. A bolt according to any preceding claim, wherein said bolt comprises carbon steel.

13. A bolt according to any preceding claim wherein said bolt is plated, said plating comprising zinc.

14. A bolt according to any preceding claim, wherein said bolt is a blade fixing bolt.

15. A bolt substantially as hereinbefore described with reference to the attached drawings.

16. A kit of parts comprising, a blade carrier, and a bolt as claimed in any proceeding claim, wherein said blade carrier comprises at least one aperture sized to engage said second section of said bolt.

17. A kit of parts according to claim 16, wherein the kit of parts further comprises a blade, and said blade comprising at least one aperture sized to engage said first section or head section of said bolt.

18. A kit of parts according to claim 16 or claim 17, the kit of parts further comprising a nut, and said nut sized to engage said thread on said third section of said bolt.

Amendment to Claims have been filed as follows

1. A bolt for a flywheel mounted blade, said bolt comprising; a head section, and

5 a shank extending from the head section, wherein said shank comprises a first section comprising a circular cross section, a second section comprising a geometric, oblong or oval cross section, and a third section comprising a thread for engaging a nut;

wherein the cross sectional diameter of said first section is greater than or equal to the 10 longest cross sectional dimension of said second section.

2. A bolt according to claim 1, wherein said head section is frustoconical.

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3. A bolt according to claim 1 or claim 2, wherein said first section is adjacent to said

15. A kit of parts according to claim 14, wherein

10 the kit of parts further comprises a blade, and said blade comprising at least one aperture sized to engage said first section or head section of said bolt.

15

16. A kit of parts according to claim 14 or claim 15, the kit of parts further comprising a nut, and said nut sized to engage said thread on said third section of said bolt.

Intellectual

Property

Office

Application No: Claims searched:

GB1616641.5

1-18

15 head section.

5. A bolt according to claim 4, wherein said third section is adjacent to said second

20 section.

25 7. A bolt according to any preceding claim, wherein a first face of said head section that opposes said shank is substantially planar.

8. A bolt according to any preceding claim, wherein said second section comprises a greater length of said shank than said first section.

9. A bolt according to any preceding claim, wherein said second section comprises a geometric cross section with chamfered or rounded corners.

10. A bolt according to any preceding claim, wherein said second section comprises a square cross section.

11. A bolt according to any preceding claim, wherein said bolt comprises carbon steel.

12. A bolt according to any preceding claim wherein said bolt is plated, said plating comprising zinc.

13. A bolt according to any preceding claim, wherein said bolt is a blade fixing bolt.

14. A kit of parts comprising, a blade carrier, and

5 a bolt as claimed in any proceeding claim, wherein said blade carrier comprises at least one aperture sized to engage said second section of said bolt.

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