TRACTOR CAB

The invention relates to a tractor cab having upright pillars which are disposed around a driver's operating area In particular, but not exclusively so, the invention relates to an agricultural tractor having a Rollover Protective Structure (ROPS)

Tractors operating under most jurisdictions require a ROPS which serves to protect the driver in the event of the tractor rolling over When fitted with a cab the ROPS is integrated with the cab frame Typically a cab comprises at least four cab pillars, a pair of front cab pillars (A- pillars) and a pair of rear cab pillars (C-pillars) It is also known to include one or two intermediate cab pillars (B-pillars) which are each disposed between the A-pillar and C-pillar and often serve to provide a rigid post to which a door can be hinged

A continuing desire of tractor cab design is to maximize the visibility of the driver so as to improve the operating conditions and even improve safety whilst keeping increases in manufacturing costs to a minimum

It is thus an object of the invention to provide a tractor cab with improved visibility for the driver without significantly increasing the number of components required

In accordance with the present invention there is provided a tractor cab comprising a roof supported by a plurality of pillars, one pillar comprising an integral window within the line of sight of a dπver, the cab further comprising a sheet of transparent material which extends from said one piilar comprising an integral window to an adjacent pillar and wherein the sheet covers said integral window

It has been recognised that a conventional cab pillar presents a visual obstruction to the dπver whether it be a front (A-pillar), an intermediate piilar (B-pillar) or a rear pillar (C-pillar) By providing a window which is integrated with the structure of the pillar the driver's visibility is improved Furthermore, the invention exploits the existing window components by extending the sheet of transparent material (e g glass) to cover the pillar and integral window This allows the inclusion of the integral window without the need for additional components Also, a plurality of windows can covered with a single piece of matenal

Preferably the pillar (or pillars) having an integral window forms part of a ROPS Preferably at least two of said cab pillars comprise an tntegral window thereby increasing the visibility of the driver further still

The cab may comprise a pair of front pillars, a pair of rear pillars and at least one intermediate cab pillar

In the case of a five-pillar cab or a stx-pillar cab (having at least one intermediate cab pillar) the intermediate pillars preferably comprise an integral window hi such a five- or six-pillar cab structure it is typically the B-pιlIar which presents the greatest obstruction to the driver's sight because it is located closest to the driver's head and, furthermore, often provides the ROPS In this case, the sheet of transparent material preferably extends from one of said rear cab pillars to the intermediate cab pillar and over the tntegral window

In a further preferred embodiment the pillar is of a truss style construction having two parallel chords and a web therebetween The web may be formed from a plurality of connecting struts for example However, in a preferred embodiment the pillar is of a Warren truss style construction and comprises a plurality of triangular integral windows formed within the web Not only is a Warren truss style construction aesthetically pleasing but it offers a particularly strong construction whilst maximizing the area of the integral window or windows

Further advantages of the present invention will become apparent from reading the following description of specific embodiments with reference to the appended drawings in which -

Figure 1 is a perspective view of a tractor in accordance with a first embodiment of the invention,

Figure 2 is a side view of part of the tractor of Figure 1 ,

Figure 3 is a rear perspective view of part of the tractor of Figure 1 showing the cab with the roof removed,

Figure 4 shows a B-pillar of the tractor of Figure I having a construction in accordance with the invention, and,

Figure 5 shows a schematic plan view of the tractor or Figure 1 showing the increased visibility provided by the invention With reference to Figure 1 a tractor 10 comprises two front wheels 12 attached to respective ends of an axle 13 and rear wheels 14. Each of the wheels has an associated fender 16 for restricting the amount of mud and debris which can otherwise fly up from the wheel whilst the tractor is in motion. A driver (not shown) sits in the driver's seat 18 whilst the tractor 10 is in operation. A cab 20 comprises a roof 22 supported by a plurality of cab pillars. The cab 20 surrounds a driver's operating area and provides protection from the outside environment which will be discussed in more detail below.

With reference also to Figures 2 and 3 the cab comprises a pair of front cab pillars 24, often referred to as A-pillars. The A-piliars 24 are each disposed at a front corner of the driver's operating area, provide support for the cab roof 22 and provide part of a rigid frame in which a front windscreen is fitted.

The cab further comprises a pair of rear cab pillars 26, often referred to as C-pillars. These are each disposed at a respective rear corner of the driver's operating area. The C-pillars 26 provide support for the rear corners of the cab roof 22 and provide part of rigid frame for a rear windscreen 27.

The A-pillars 24 and C-ptHars 26 are formed from tubular steel which is bent into shape and welded during manufacture. The tops of the A-pillars 24 and C-pillars 26 are welded to a roof frame structure 28 which is also formed of tubular steel.

The cab 20 further comprises a pair of intermediate pillars 30 which are each disposed forward of the C pillars 26 above the fender 16 of the rear wheel 14. Each intermediate pillar 30, often referred to as B-pillars, is welded at its bottom end to a tower part of the driver's operating area and at its top part to the cab roof support structure 28. The B-pillars 30 provide extra support for the cab whilst also providing, together with the cab roof support structure 28, the ROPS which is a legislative requirement in most countries.

Alternatively, the pillars can instead be bolted to the tractor frame at their lower end and may instead be formed from aluminium for example.

In accordance with the invention each B-pillar 30 comprises a plurality of integral windows 32 within the line of sight of the driver. The windows 32 are provided by forming the B-pillar having a Warren truss style construction. With reference also to Figure 4, this style of truss construction comprises angled struts 34 connecting a pair of parallel chords 36 The chords 36 and the struts 34 are welded together so as to leave triangular integral windows 32 aligned substantially transversely to the forward direction of the tractor 10 The Warren truss-style construction provides a sufficiently strong support for the ROPS

In accordance with the invention a single sheet of glass 40 extends from each respective C piϊlar 26 to the adjacent B-pillar and over the integral windows 32 However, it should be recognised that alternative transparent material may be employed instead of glass, such as plastic Each sheet 40 extends the full height of the pillars and forms a watertight seal with the cab roof 22 along the top and the fender 16 along the bottom The glass sheet 40 is alfixed to the respective pillars and horizontal frame work using known techniques such as a rubber, waterproof, seal (not shown)

By employing a single sheet of glass 40 no extra glazing is required for the additional windows 32, thus minimising extra cost The windows 32 of the B-pillars 30 deliver improved visibility to the driver whilst also forming part of the cab structure

In addition to providing support for the cab structure each B-piHar 30 provides a post upon which a cab door (not shown) can be hinged

With reference to Figure 5 it can be seen that the invention delivers a significant increase in the visibility for the driver The field of vision represented by X of a driver (represented at 100) is significantly improved by the invention A traditional, completely opaque, B-pillar would completely block the field of view X located to the driver's immediate left and right sides By providing at least one integral window 32 in each B-pillar 30 the driver's vision over range X is at feast significantly improved This is particularly advantageous from a safety perspective when driving on the public highway wherein the dπver s blind spot is reduced in size if not completely eradicated

It should be understood that a pillar in accordance with the invention can be formed with a truss style construction having an alternative web lay out without deviating from the scope of the invention That is to say that the struts 34 which connect the parallel chords 36 can alternatively be arranged leaving rectangular windows for example Alternatively further still, it is envisaged that a truss having a web of diagonal and horizontal struts can instead be employed In a very basic alternative to that described the pillar may comprise a single window wherein a truss style construction is not required.

Furthermore it should be appreciated that the A-pillars 24 and/or C pillars 26 could instead, or additionally, comprise an integral window whilst remaining within the scope of the invention.

In summary there is provided a tractor having at least one pillar adjacent a dπver's operating area. The pillar comprises and integral window within the lme of sight of the driver thereby improving the visibility thereof dunng the operation of the tractor. The integral window is covered by an extension of the window pane whteh covers a window defined between the associated pillar and an adjacent pillar, typically adjacent B- and C-pillars. A truss-style construction can be employed for the pillars wherein windows are provided in the gaps between the webbing.