GB2610391A

GB2610391A - Screen guard

Info

Publication number: GB2610391A
Application number: GB2112467.2A
Authority: GB
Inventors: Milburn Michael
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-09-01
Filing date: 2021-09-01
Publication date: 2023-03-08
Also published as: GB202112467D0

Abstract

A screen guard (10, fig.2) for use on the cab of a work machine comprises a metal sheet provided with a plurality of substantially rectangular shaped holes (22) arranged in rows. The screen guard has a front face, a top edge, a bottom edge and at least two side edges 24,24’,28,28’ wherein each of the edges extends away from the front face at an angle such that in use the front face of the screen guard is spaced apart from the windscreen by the edges. Both the top and bottom edges of the screen guard include attachment means 15, 18, 20, for attaching the screen guard to the machine. Each hole has a pair of substantially parallel and vertical vertices (see fig.3), and the holes are presented in a regular staggered pattern such that the vertical vertices of the holes are aligned on alternate rows and there is a metal spacing (13) surrounding each opening. The guard may comprise two parts 12,14 that may be joined by at least one hinge 16. There may be a gap 26 defined by the side edges to accommodate a windscreen wiper (34) of the machine.

Description

Screen Guard

Field of the Invention

The present invention relates to screen guards, and in particular to windscreen protection guards to be used on the cabs of demolition machinery.

Background of the Invention

The use of construction and/or agricultural work machines such as hydraulic excavators, cranes and tractors, in particular excavator mounted rock breaking and concrete cutting machines, can result in flying debris such as small fragments of rock or stone or gravel. Such fragments of debris can pierce the windscreen of the cab and can cause injury to the driver. A number of operators of such machinery have received eye injuries in this Way.

Mesh windscreen guards that attempt to address this problem are sold by CabCare Products Limited. These mesh guards are fabricated from 3mm steel with 50mm x 25narn holes punched through it in a regular grid pattern with 5mna of steel between each of the holes. This layout of holes provides 76% of open area, however this type of windscreen guard lacks strength and can allow projectiles to hit and deform the steel mesh and potentially cause damage to the windscreen and the operator.

US9151016 describes a protective guard for a machine such as a hydraulic excavator which include a cab in which an operator sits. The guard comprises a number of horizontal and vertical plate members that are arranged in a grid pattern.

LS2015/0123428 describes a cab protection apparatus for protecting an operator of an excavator, primarily if the excavator is turned upside down or if a heavy object is dropped onto the cab.

USD765737 describes a window guard for tractors.

W02017/124144 describes a demountable shield apparatus for shield a rear window of a row vehicle US5954384 describes a windshield protection guard for a vehicle comprising a wire mesh Guard.

JP2007-154477 describes a grille for use on the cab of an excavator.

Existing windscreen guards either suffer from the drawback that they have improved rigidity but reduced visibility through the windscreen, or mproyed visibility but reduced rigidity and strength.

Where the screen guards are made from steel wires in order to improve the strength of the guard the diameter of the steel wires must be increased, which in turn leads to deterioration of the visibility from the operator's seat.

It would be desirable to provide an imp roved screen guard which has improved strength whilst maintaining good visibility.

Summary of the Invention

According to the invention there is provided a screen guard for use on the cab of a work machine comprising a metal sheet provided with a plurality of substantially rectangular shaped holes arranged in rows, the screen guard having a front face, a top edge, a bottom edge and at least two side edges wherein each of the edges extends away from the front face at an angle such that in use the front face of the screen guard is spaced apart from the windscreen by the edges. Both the top and bottom edges of the screen guard include attachment means for attaching the screen guard to the machine. Each hole has a pair of substantially parallel and vertical vertices, and the holes are presented in a regular staggered pattern such that the vertical vertices of the square holes are aligned on alternate rows and there is a metal spacing surrounding each opening.

The attachment means of the top edge of the screen guard preferably includes hooked means suitable for attaching the screen guard to a rail located on the machine. The top edge of the screen guard is preferably folded into a hooked shape enabling the top edge of the screen guard to hook over a rail.

The screen guard is preferably formed in two parts. The two parts are preferably joined together via at least one hinged element. This enables the screen guard to match any curvature in the cab of the vehicle to which it is affixed.

Preferably at least one of the side edges includes a gap sized to accommodate windscreen wiper located on the machine.

Preferably, the openings have a substantially square shape.

Preferably each opening has four vertices, each vertex having a length, and the metal spacing has a width equal to the distance between parallel vertices on adjacent openings. Preferably the length of each vertex is at least live times larger than the width of the metal spacing. I i;ach vertex may have a length of approximately 15mm and each metal spacing may have a width of approximately 3mm.

Preferably each of the edges of the screen guard extends away from the front face at an angle of substantially 90 degrees.

The strength of a screen guard can be improved by increasing the amount of steel making up the guard and/or by decreasing the sizes of the holes therein, however this has the effect of reducing the open area of the screen guard which can cause he visibility through the screen to deteriorate. The inventor has surprisingly found that by providing a grille with a staao-ered pattern of holes, the visibility through the screen is dramatically improved, whilst strength of the screen is also maintained or improved. It is thought that visibility through the screen is improved because the operator is presented with different blind spots in every alternate row of holes.

Brief Description of the Drawings

In the Drawings, which illustrate preferred embodiments of the screen guard of the invention: Figure 1 is a schematic front plan view of a screen guard; Figure 2 is a schematic rear plan view of the screen guard of Figure 1; Figure 3 is a schematic enlarged view of a portion of the mesh part of the screen of Fig. 1 Figure 4a is a schematic side view of the screen guard of Figure 1; Figure 4b is a schematic view of the opposite side of the screen guard of Figure 1; Figure 5 is a perspective view of the screen guard of Figure 1; and Figure 6 illustrates the screen guard of Figure I attached to the cab of a work machine.

Detailed Description of the Preferred Embodiments

Figure 1 illustrates a schematic plan view of a screen guard 10 of the invention. The screen guard 10 is made up of Iwo s: an upper part 12 which is designed to cover the upper section of the windscreen of a vehicle cab and a lower part 14 for covering the lower section of the vehicle cab. the two sections are joined together by a pair of hinges 16. Hinging of the two parts allows the guard to match the curvature of the cab. The two parts could instead be welded together to match the curvature of the cab. "I the screen guard 10 could also be formed in one piece shaped to cover the cab.

The lower section of the screen 14 includes two attachment members 18. In the illustrated example the attachment member comprise a snap lock system which is widely available and sold by CabCare Products Limited. The snap lock system comprises a lock box 18 which includes a locking pin 20 therein, forming the male part of the lock system. The lock box 18 and pin 20 engage with a complementary female part comprising a receiver plate which is mounted on the cab Mot shown). The lock box 18 and pin 20 snap and lock into position on the receiver plate. A special key is used to unlock the pin. The snap lock system can be used to attach the screen guard 10 to the machine since most construction vehicles of this type are already equipped with the female receiver plate of this type of snap lock system. An alternative means for attaching the screen guard to the machine would be using a combination of bolt holes and boles.

As illustrated in Figures 2, 4a and 4b, the top edge 15 of the upper part 12 of the screen guard is folded over to form a hooked portion 15a, allowing the screen guard 10 to be hung from a guard rail 30 which is typically present above the windscreen of a cab, as shown more clearly in Figure 6.

The central area of each section is provided with a mesh to allow the driver of the vehicle to see through the windscreen. As illustrated, the mesh comprises a series of rectangular or square openings or holes 11 which are provided in an offset or staggered pattern, such that the vertical edges of the holes are aligned on each alternate rows as illustrated more clearly by the dotted lines in the close up in Figure 3.

In the illustrated examples, the holes are square, with four equal vertices, and each have dimensions of approximately 15mm x 15mm (X x Yin Figure 4). Each hole is surrounded by a metal spacing 13 with a width (V) of approximately 3rnm. The width (/) of the metal spacing is equal to the distance between parallel vertices on adjacent holes. This size of holes provides 69% of open area, and improves the strength of the screen guard. Surprisingly, the offset layout of squares improves visibility.

The screen guard is made from steel, preferably approximately 2mrn in thickness, and the mesh holes are cut into the screen using a laser. As shown more clearly in Figures 4a and 4b, the des of the screen are folded to provide solid edges 24, 24', 28, 28' which prevent any flying debris from getting to the windscreen from the side. Each of the solid edges extends away from the front face such that the front face of the screen guard is spaced apart from the windscreen The screen guard needs to be sufficiently distant from the windscreen so that an impact from flying debris does not cause sufficient deflection to hit the windscreen. In the illustrated example the edges are 53 mm in depth, spacing the front face of the screen guard apart from the windscreen of the vehicle by a similar amount. There is a gap 26 on one side of the upper part 12 of the screen guard to accommodate the windscreen wiper 34 of the machine 32 as illustrated in Figure 6. The gap 26 for the windscreen wiper can be on either side of the screen guard, depending on the model of machine.

'figure 6 illustrates the screen guard 10 in place on the cab of an excavator machine 32. The lower part of the screen 14 is shown attached to the machine via the snap lock system as described previously, and the upper, hooked edge 15a of the screen guard hangs from a guard rail 30 above the windscreen.

Claims

Claims 1. A screen guard for use on the cab of a work machine comprising a metal sheet provided with a plurality of substantially rectangular shaped openings arranged in rows, the screen guard having a front face, a top edge, a bottom edge and at least two side edges wherein each of the edges extends away from the front face at an angle such that in use the front face of the screen guard is spaced apart from the windscreen by the edges, and wherein both the top and bottom edges of the screen guard include attachment means for attaching the screen guard to the machine; wherein each opening has a pair of substantially parallel and vertical vertices, and the openings are presented in a regular, staggered pattern such that the vertical vertices of the openings are aligned on alternate rows and there is a metal spacing surrounding each opening.
A screen guard according to Claim 1, wherein the attachment means of the top edge includes hooked means suitable for attaching the screen guard to a rail located on the machine.
3. A screen guard according to Claim l or 2, where the screen guard is formed in two parts.
4. A screen guard according to any preceding claim, wherein the two parts are joined together via at least one hinged element.
5. A screen guard according to any preceding claim, wherein at least one of the side edges includes a gap sized to accommodate windscreen wiper located on the machine.
6. A screen guard according to any preceding claim, wherein the openings have a substantially square shape.
7. A screen guard according to any preceding claim each opening having four vertices, each vertex having a length, wherein the metal spacing has a width equal to the distance between parallel vertices on adjacent openings, and wherein the length of each vertex is at least hve times larger than the width of the metal spacing.
8. A screen guard according to Claim 7, where each vertex has a length of approximately 15rnrn and each metal spacing has a width of approximately 3mm.
9. A screen guard according to any preceding claim wherein each of the edges extends away from the front face at an angle of substantially 90 degrees.S