AU608399B2 - Harvester knife back - Google Patents

Description

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g i~lilk- -~i*SiW Form COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-62 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Application Number: Lodged: Comnp'Iete SpeCifiCation Lodged: Accepted: Published: Priority: Related Art: Class Int. Class TO BE COMPLETED BY APPLICANT Name t Applicant: HARVESTAIRE PTY. LTD.

A'dross of Applicant: 18 Mumford Place, Balcatta, State of Commonwealth of Australia Western Australia, Actual Inventor: DONALD GEORGE BROOKS and JOHN HAROLD FAFLING Address for Service: Care of R.K. MADDERN ASSOCIATES, 345 King William Street, Adelaide, State of South Australia, Commonwealth of Australia Complete Specification for the iriention entitled: "HARVESTER KNIFE BACK" The following statemeni ts a full description of this invention, including the best method of performing It known to -mer us This invention relates to a knife back (bar) for supporting an array of knives on a harvester of the type which utilises an array of knife blades reciprocating transversely with respect to the direction of travel of the harvester.

BACKGROUND OF THE INVENTION The cutting platforms of many modern harvesters off t in a range of 20 to 30 feet in length, and usually the reciprocating knife comprises a single length knife back 10. to which knife sections and a knife head are attached of to make a knife assembly.

The single length knife back has limitations, #foe parcicularly in that when the knife back becomes bent of or broken (not an uncommon happening) usually due to continuous heavy cutting, fatigue, or hitting a foreign object, it is costly to replace due to a complete new knife being required, or the knife sections and head o.*0 needing to be totally removed and then re-attached to the new knife back. This is coupled with the difficulty of supply and transport of a long length, which is usually supported by wood and strapping, to towns or areas sometimes a considerable distance away from the factory where it is made.

There have been attempts to partially overcome the above problem ir recent years, including supply of a knife back in short lengths with a machined step at each end of each length such that when joined they form the 1 complete knife back. They can only be replaced on the farm in those lengths.

This constitutes an improvement over a single elongate bar, but the cost of machining the steps is high. Furthermore, to retain the bolts from turning when nuts are used to tighten knife blades onto the knife back, the bolts which have been used previously have sometimes been formed with radially outstanding but longitudinally extending serrations, but manufacturing tolerance difficulties resulted in some bolts not gripping sufficiently and some havrn too much interference. There are large numbers of bolts in a -ong knife back, and if a high proportion have a large interference, the knife back length is caused to be increased so that the knife back may not retain correct relationship with the remaining parts of the harvester.

Still further, the stepped bar arrangement sometimos requires further securing apertures to be drilled through the knives, which are of metal which has been hardened.

This is very inconvenient, and the alternative is to provide special purpose knife sections, each containing four apertures.

An object of this invention is to provide an improvement whereby a knife back can be retained at low cost, wherein damage is less likely to occur, wherein a single pattern knife back can be used on any one of several harvester makes wherein securing aperture 3 locations vary from other machines, and wherein the knife back comprises a plurality of short length bar portions.

Different manufacturers produce knife bars of similar but not identical pitch for supporting knives having slightly different hole centre distances, but it is desirable that a knife back be usableon any one of several machines, and in an embodiment of this invention alternate apertures are elongate along the direction of the knife back so that small dimensional variations may be accommodated.

BRIEF SUMMARY OF THE INVENTION t °In an embodiment of this invention, a knife back t it comprises a series of bar portions arranged in a twotier lamination, the bar portions of the upper tier being I t i I It staggered with respect to those of the lower tier, each lower tier bar portion having a plurality of holes at such centres that they vertically align with holes in upper tier bar portions, and a plurality of fasteners extending through respective aligned holes and also through holes in knife blades to thereby retain the knife back laminated bar portions and the knife blades in an assembly.

More specifically, the invention consists of a harvester knife back for supporting an array of knives on a harvester of the type which utilises a plurality of knife blades reciprocating transversely with respect to the direction of travel of the harvester, comprising a series of bar portions in a two-tier lamination, the 4 I- i I 0 o 0 0a C S00 09 0 0 0~ 00 0 0 o o0 0r 0 0* o 0000 *r~ bar portions of an upper tier being staggered with respect to the bar portions of a lower tier, each lower bar portion having surfaces defining a row of apertures therethrough which align with apertures in an overlying bar portion sufficiently to receive a knife securing bolt.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment is described hereunder in some further detail with reference to and is illustrated in the 10. accompanying drawings in which: The first drawing illustrates a front elevation of portion of the knife bar assembly, as in prior art, Fig. 1 is a similar drawing showing a knife back assembly according to this invention, Fig. 2 is a fragmentary perspective view drawn to a larger scale which illustrates the interconnection between the knife bar portions of the knife back, and a knife, and Fig. 3 is a plan view of portion of the knife back drawn to a larger scale and showing the outlines of knives in broken lines.

As shown in the upper drawing a prior art knife back 10 comprises a single bar which has fastened to it a plurality of knife blades 11, the fasteners for example being rivets, or screw-threaded fasteners.

As shown in Fig. 1, in order to reduce the very considerable length of the knife bar 10, it comprises 5 a plurality of portions in this invention, arranged in a two-tier lamination, there being a plurality of upper knife bar portions 12a and a plurality of lower knife bar portions 12b, each portion being only part of the length of the knife back, and the portions 12a being end to end, the portions 12b being end to end, and the portions 12a and 12b being staggered with respect to S one another.

Knife blades 13 are in accordance with prior art 10. and each comprise apertures 14, and these apertures 14 9e align sufficiently with the apertures 15 in the upper knife bar portions 12a and apertures 16 in the lower knife bar portions 12b to accept fasteners. As zshown in Fig. 2, the apertures 14 are circular apertures and these r t receive the threaded portion 17 of each of a plurality of clamping bolts 18, the clamping bolts 18 having square shoulders 19 on their shanks ("coach head bolts"). The square shoulders 19 engage parallel walls of the square apertures 16a or the rectangular apertures 16b to prevent rotation of the coach head bolts, while the threaded portion 17 passes through-the circular apertures 14.

Using alternate square and rectangular apertures and 15a, 16a and 16b, to receive each bolt, bolts 18 provide a means whereby the laminated two-tier bar can accommodate knives of varying pitch dimension, for use on harvesters of alternative manufacture. Nuts 20 clamp the upper and lower bar portions and th) knife blades y; 6 together as an assembly. The rectangular apertures are elongate in the longitudinal direction of the bar portions.

For this arrangement, the retention of the clamping bolts 18 to liie knife bar assemblies is facilitated since the bolts are prevented from rotation when the nuts are being screwed thereto.

4r o The laminated knife back of this invention has the oo following advantages over systems otherwise known to

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the Applicant It is low cost and needs no machined steps, no extra S po holes through the knife blades, and uses no nonstandard knife sections.

C0 o It is replaceable in sections or part sections of different lengths, and staggering the upper bar with respect to the lower bar provides the required length.

Any damaged part can be cut out with a hand held hacksaw on site without the need to return to the workshop, the laminations again being overlapped and the knife back put together. The amount cut out may be simple added to the free end to make up the length.

The invention enables a knife baik to be supplied in various lengths by simply overlapping and refastening (with bolts or rivets) anywhere along its length. This enables a store in any local or 7 outlying area to easily supply knife backs and therefore complete knife assemblies to suit different harvesting and mowing machines in the area usually irrespective of make, model or length of cutting platform, it being necessary to hold only a minimum of stock of standard lengths of two tiered laminated bar.

If alternate square and rectangular holes are punched along each upper and lower length at regular pitch intervals, then square type "coach head" bolts may be used to allow the knife back to be c. zembled very easily and simply, by using any one of a variety of existing knife sections and knife heads which have attachment holes of varying pitch distances as specified by different harvester manufacturers. The "coach head" bolts can be moved along within each rectangular aperture to accommodatG the different pitch lengths and then tightened.

Consideration of the above embodiment will indicate that the invention is very simple but nevertheless facilitates the assembly of a knife back for a wide harvester, facilitates knife replacement, and facilitates reolacement of any badly worn or damaged knife back portion, often avoiding need to replace the entire knife back.

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Claims (4)

1. A harvester knife back for supporting an array of knives on a harvester of the type which utilises a plurality of knife blades reciprocating transversely with respect to the direction of travel of the harvester, comprising a series of bar portions in a two-tier lamination, the bar portions of an upper tier being staggered with respect to the bar portions of a lower tier, each lower bar portion having surfaces defining a row of apertures therethrough which align with It apertures in an overlying bar portion sufficiently to tlt receive a knife section securing bolt. Of

2. A harvester knife back according to claim 1 wherein said apertures of each bar portion comprise alternate apertures of generally square and rectangular shape, said aperturies overlying one another in said upper and 44 5. lower tiers.

3. A harvester knife back according to claim 2 wherein the rectangular apertures are elongate in the longitudinal direction of the bar portions.

4. A knife and knife back assembly comprising a harvester knife back according to claim 2, an array of knife blades, a plurality of pairs of clamping bolts extending through said aligned square and rectangular apertures of the bar portions and through apertures in the knife blades, aid nuts on the clamping bolts clamping the bar portions and knife blades together. 9 A harvester knife back assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. Dated this 4th day of January, 1989 HARVESTAIRE PTY. LTD. By its Patent Attorneys, R.K. MADDERN ASSOCIATES. c t t t E SE tb t 10