GB2529215A

GB2529215A - A blade jig

Info

Publication number: GB2529215A
Application number: GB1414412.5A
Authority: GB
Inventors: Martin Kay
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-08-14
Filing date: 2014-08-14
Publication date: 2016-02-17
Also published as: GB201414412D0

Abstract

A blade jig comprises an elongate body having a plurality of holders for spaced receipt of a plurality of blades to prevent relative rotation of the blades, wherein at least one holder comprises a clamp 30 arranged to clamp laterally around a blade and at least one holder comprises a catch arranged to hold a blade vertically. Preferably, the blades are, in use, orthogonally arranged by the jig. The jig may be used to receive blades that are elongate and are arranged to rotate on central pivots that are spaced apart from each other. The clamps may each comprise a grip (31, figure 6) and a lacuna (32) for insertion of a blade. The jig may be used to mutually configure two blades of a dual-bladed lawnmower.

Description

A BLADE JIG

Field of the Invention

The present invention relates to a blade jig, in particular a jig for mutually configuring two blades; more particularly but not exclusively a jig for dual bladed lawnmowers or the like.

Background

A common design feature of ride-on mowers (also known as lawn tractor mowers) and some types of towed grass mowers is deck housing two or more intermeshing or overlapping rotary blades. This feature enables the mower to cut a wide, even swath without leaving an untidy ridge inbetween the swaths of the individual blades. Where intermeshing blades are installed, they are often driven by a toothed endless belt engaging sprockets fixed to the blade rotational spindles and timed (otherwise known as phasing, synchronising or aligning) so that the blades do not contact during rotation which may result in damage to the mower, injury to operators and others nearby.

The usual method of timing blades is to set the long axis of the blades at 90 degree to one another and install the toothed drive belt. The blades rotate freely and although timing reference marks are usually provided, achieving the correct 90 degree phasing can be an awkward and demanding task for many owner/users, as blades, drive and idler sprockets will typically have to be aligned and a stiff drive belt correctly engaged on each item. Many people therefore resort to using scrap timbers, woodworker's clamps and similar improvised methods for holding the blades in place while the belt is fitted. This is unsatisfactory as it is difficult to achieve the correct 90 degree blade spacing by eye, wherein timing marks and the belt are likely to be on the opposite side of the deck to the blades and hence blades and timing marks are not visible at the same time. Improvised blade restraint methods do not always hold the blades securely and are prone to slip if significant torque is applied to remove or install a blade retaining bolt, usually resulting in painful skinned knuckles and damage to bolt heads. The risk of more serious injury from an uncontrolled rotating blade cutting edge cannot be overlooked. a

Prior Art

Accordingly a number of patent applications have been filed in an attempt to resolve the problem or similar, including the following: Granted United States patent US 8 209 837 (HENSHAW) discloses a tool for locking and removing of a rotary blade of a power lawn mower having a standard deck said tool needing no movable adjustment parts to install on said power lawn mower and being comprised of: a one piece member consisting of a first flat surface having a front, back and two sides upon which the blade is held, a second flat surface integral and perpendicular to the front of said first flat surface for lodging against a protuberance on the mower deck, third and fourth flat surfaces integral and perpendicular to said sides of said first flat surface for retaining said blade from rotation, said third and fourth flat surfaces having holes therein to accept blade retaining means when said tool is installed on said mower, said second surface is located on the outside surface of said deck and said third and fourth flat surfaces are located on the interior of said deck so that when said second flat surface engages the protuberance on said deck said blade is locked in place so that the removal of said blade can be accomplished.

Granted United States patent US 6 925 787 (BERNTSON) discloses a rotary blade blocker secured to a perimeter edge of a deck of a rotary-type mower to prevent inadvertent firing of an internal combustion engine of the mower during rotary blade removal and replacement or during manual debris removal from withina mower deck of the mower, consisting of: an L-shaped bracket having a threaded clamping member dependently attached to, and adjustably moveable with respect to an inner facing surface of, one leg of said bracket; a blocking member connected on an inner surface of a second leg of said bracket in spaced limitedly adjustable relation and forming a gap of adjustable width with respect to a proximal end of said clamping member extending from the inner facing surface of said one leg, said gap adjustably sized and received over a lower edge of the deck and secured by tightening of said clamping member against an outer surface of the edge of the deck, a lateral surface of said blocking member making non-entrapping contact with, and preventing rotation of the rotary blade in one direction in an amount sufficient to cause inadvertent firing of the engine during blade replacement or debris removal from within the deck.

Summary of the Invention

According to the present invention there is provided a blade jig, comprising an elongate body having a plurality of holders for spaced receipt of rotating blades so as to prevent relative rotation, wherein at least one holder comprises a clamp which clamp is arranged to clamp around a blade laterally and at least one holder comprises a grip arranged to hold a blade vertically.

Typically two blades and two holders are provided in preferred embodiments. Other embodiments may include three blades and consequently three holders. In such embodiments at least one of the holders may be a fixed holder. In addition or the alternative such embodiments, or those with further blades and holders, may comprise braces or adjustable braces. Such braces are ideally configured to attach to other parts of machinery containing the blades. Typically in such embodiments the blades are arranged in use at fixed angles relative to one another, wherein the blades are arrangeable into such fixed arrangement by use of the jig.

In preferred embodiments the blades are orthogonally arranged in use by the jig, wherein the blades are elongate and arranged to rotate about axes of rotation or pivots, and wherein the blades have spaced apart central pivots.

Typically the pivots are spaced apart and the blades rotate simultaneously in use wherein the blades may be set before use and engagement of a drive means such as a motor.

The clamp is provided with at least one moveable part wherein the blade can be inserted into the member by dislocation or displacement of the part.

In some embodiments the displaceable part or parts allow(s) variance of clamp width.

In this way the jig may be adjusted for different blade shapes or dimensions and/or relative spacing.

The grip may be arranged with a fixed through-lacuna suitable for insertion of the blade wherein typically the grip includes a plate or bar member placed substantially parallel to the body and two sides, in all forming a rectangular through lacuna with the body as the fourth edge thereof.

Such lacuna may be usable to maintain the blade in a stable plane, so as to permit correct positioning on the pivot and attachment thereto.

In preferred embodiments the grip may comprise at least one displaceable portion, which portion is displaced to allow entrance of the blade into the lacuna. Such portion may comprise the member.

In addition or the alternative by use of a displaceable portion the jig can be more effectively placed onto the blades and the blades more effectively set relative to one another. In some embodiments the lacuna may include padding or resiliently deformable material so as to cushion or grip the blade.

In order to prevent damage to the blades the jig enables the blades to be set orthogonal to each other, or at recommended fixed angles relative to one another, during attachment to a mower or other similar apparatus.

In preferred embodiments the jig holders provide both grips and clamps wherein the grips and clamps are analogous and providing maximal adjustment possibilities. In this way the grips and clamps are advantageously combined into holders for the blades, which holders are configured to prevent movement of the blade both laterally and longitudinally.

In preferred embodiments the holders are arranged or arrangeable in plural positions on the body as well as or in addition to orthogonal end parts. For example the body may comprise plural fixing positions for the holders, clamps or grips.

In preferred embodiments the holders, grips or clamps include portions for guiding the blade at least in part, for example wherein the portions follow the blade longitudinal axis from blade tip to rotational axial centre.

Ideally at least one of the holders, grips or clamps comprises an elongated sidewall, which sidewall directs the blade, further maximising effective directioning of the blade.

In preferred embodiments the body is rigid, and in use describes at least one right angle wherein the holders extend parallel from a central body, typically from the body's ends. In some embodiments the ends and/or holders may be adjusted or rotated with respect to the body, for example wherein a means of articulation is included on the body, ends andlor holders.

In some embodiments the body may be articulated or flexible wherein relative positioning of its ends may be altered by alteration of the body alone.

In some embodiments the body and ends comprise displaceable or detachable fittings, wherein the holders may be displaced from the body.

Preferably the ends and body are fixed in configuration of angles wherein 1 5 advantageously the relative arrangement of the holders is ideally adjustable along and within the same configuration for variant blade sizes, and the blades are consequently easy to fix.

Brief DescriDtion of Figures Figure 1 shows a sketch of an embodiment of the jig according to the present invention; Figure 2 shows a sketch of the embodiment of the jig shown in Figure 2, in use; Figures 3 show sketches of detail views of the embodiment shown in Figure 1 interacting in use; Figure 4 shows a sketch of a known blade drive train; Figure 5 shows a view from below of a second embodiment of the jig according to the present invention; And Figure 6 shows a side view of the embodiment shown in Figure 5.

G

Detailed Description of Figures

With reference to the figures of the first embodiment there is shown a rigid jig comprising an elongate body and two ends deviating therefrom at 90 degrees, forming right angled corners. The body, ends and holders' sides are formed of perforated steel plates, which may be powdercoated or painted.

The body and ends are rectangular, and comprise L shaped girder pieces, which pieces have a greater width in plan view than height in side view. The pieces have multiple regular spaced perforations forming holes for adjustment where subsequent pieces are to be fixed.

For example the ends may be displaced along the body away from the literal ends of the body, towards the body middle.

One of the ends 22 is provided by a side of the clamp 4.

Two holders are arranged on the body 1 and end 2, wherein the holders comprise grip means to limit items held in the holders from movement in a vertical plane, as defined orthogonal to the body. Further embodiments may include further holders, for example for setting different angles or for different numbers of blades. For example in some embodiments two intersected bodies may be utilised.

The holders also comprise clamps, wherein said clamps comprise means to limit movement in a lateral plane, defined by the body's length.

The holders include adjustment means with respect to grip depth, so as to accommodate variant thickness of blade and blades and relative differences in height thereof.

The grip is formed by the end and a grip bar, which together act to provide a fixed lacuna in use, into which the blade may be slid or which in use may be fixed over the blade. The bars are threaded steel bars, held into the sides by end nuts. In some embodiments the nuts may consist of wing nuts for hand-tightening.

In yet further embodiments quick release mechanisms may be employed instead of threaded nuts. Such mechanisms may include overcentre sprung catches.

Such adjustment is provided by a variety of different fixing positions on the grips' sides wherein the grip bar has multiple fixing holes or perforations. In this way prior to use the jig may be configured for the particular usage.

The holders include adjustment means with respect to clamp width, so as to accommodate variance in blade width. The adjustment means comprises the multiple holes, wherein the end may be moved on the body and/or the opposing side may also be moved on the body.

In addition or the alternative the bar may be adjusted on the sides, wherein the sides comprise plural adjustment holes also.

In both embodiments some of the holes in the pictured embodiment are slots, wherein further adjustment is possible.

With reference to the second embodiment the body only has one extending end, wherein one of the holders is attached to the body and the other on a deviated end 2.

The holders are pictured in Figures 5 and 6 are comprised of clamps 30 and grips 31, wherein the grips 31 comprise a lacuna 32 between the body or end; and clamps 30 comprised of two sides 4, which are adjustable in width by nuts 60 and bolts 50.

Figure 4 shows a sketch of an example of a known blade drive train, consisting of two large blade drive sprockets, two smaller idlers, which serve to control belt tension, and the toothed belt in contact with all four. Timing marks (small dots) are visible on the left hand sprocket at 12 and 6 o'clock.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention. Firstly it will be understood that any features described in relation to any particular embodiment may be featured in combinations with other embodiments.

With respect to the specification therefore, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention, with variation and implementation obvious and clear on the basis of either common general knowledge or of expert knowledge in the field concerned. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as set out in the accompanying claims.

Claims

Claims 1. A blade jig, comprising an elongate body having having a plurality of holders for spaced receipt of rotating blades so as to prevent relative rotation, wherein at least one holder comprises a clamp which clamp is arranged to clamp around a blade laterally and at least one holder comprises a catch arranged to hold a blade vertically.
2. A blade jig according to claim I wherein the blades are orthogonally arranged in use by the jig, wherein the blades are elongate and arranged to rotate about axes of rotation on pivots, and wherein the blades have spaced apart central pivots.
3. A blade jig according to claim 1 or 2 wherein the clamp is provided with at least one moveable part wherein the blade can be inserted into the member by dislocation or displacement of the part.
4. A blade jig according to any of claims 1, 2 or 3 wherein the grip may be arranged with a fixed through-lacuna suitable for insertion of the blade 5. A blade jig according to claim 5 wherein the grip comprises at least one displaceable portion, which portion is displaced to allow entrance of the blade into the lacuna.6. A blade jig according to claims 4 or 5 wherein the lacuna includes padding or resiliently d!formable material so as to cushion or grip the blade.7. A blade jig according to any of the preceding claims wherein the holders provide both grips and clamps.8. A blade jig according to any of the preceding claims wherein the holders include portions for guiding along the blade at least in part.9. A blade jig according to claim 8 wherein the holder comprises an elongated sidewall.10. A blade jig according to claim 10 wherein the body describes at least one right angle.ID11. A blade jig according to claim 11 wherein the right angle is at an end of the body.12. A blade jig according to claim 11 wherein two right angles are at either end of the body.13. A blade jig according to any of the preceding claims wherein holders extend along parallel axes from a central body.14. A blade jig according to any of the preceding claims wherein the holders may be adjusted or rotated with respect to the body.15. A blade jig according to any of the preceding claims wherein the body is rigid.16. A blade jig according to any of the preceding claims ito 14 having a flexible body at least in part.17. A blade jig according to any of the preceding claims wherein the body is articulated.18. A blade jig according to any of the preceding claims wherein the holders are displaceable.19. A blade jig according to any of the preceding claims 1 to 14 wherein the holders and body are in a fixed configuration of angles.20. A blade jig substantially as described herein with reference to the figures.Amendments to the claims have been filed as follows: Claims 1. A blade jig, comprising an elongate body having a plurality of spaced apart holders, each holder being arranged in use to receive a rotating blade, in which the plurality of holders are arranged in use so as to prevent relative rotation of a plurality of rotating blades having spaced apart axes of rotation, wherein at least one holder is configured to prevent lateral and longitudinal movement of a blade.2. A blade jig as claimed in claim 1, in which the jig comprises an end extending from each end of the elongate body and deviating therefrom at an angle of 90 degrees.3. A blade jig as claimed in claim 2, in which each end comprises a holder.4. A blade jig according to any one of claims 1 to 3, wherein at least one holder UD comprises a clamp, and in which the clamp is provided with at least one moveable part wherein the blade can be inserted into the member by (O dislocation or displacement of the part.
5. A blade jig according to any one of claims ito 4 wherein the clamp comprises (0 a fixed through-lacuna arranged to receive the blade (4
6. A blade jig according to claim 5 wherein the clamp comprises at least one displaceable portion, which portion is displaced to allow entrance of the blade into the lacuna.
7. A blade jig according to claims 5 016 wherein the lacuna includes padding or resiliently deformable material.
8. A blade jig according to any of the preceding claims wherein the holders include portions for guiding along the blade at least in part.
9. A blade jig according to claim 8 wherein the holder comprises an elongated sidewall.
10. A blade jig according to any of the preceding claims wherein holders extend along parallel axes from a central body.
11. A blade jig according to any of the preceding claims wherein the holders are adjustable or rotatable with respect to the body.
12. A blade jig according to any of the preceding claims wherein the body is rigid.
13. A blade jig according to any of the preceding claims ito 12 having a flexible body at least in part.
14. A blade jig according to any of the preceding claims wherein the body is articulated.
15. A blade jig according to any of the preceding claims wherein the holders are displaceable.IC)
16. A blade jig according to any of the preceding claims 1 to 15 wherein the " 20 holders and body are in a fixed configuration of angles. (00
17. A blade jig substantially as described herein with reference to the figures. (0 (4