GOODS BODIES for• RAPT
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UNLOADING
Arranging Lorry Bodywork for Tipping and for the Self discharge of• a Variety of Bulk Loads, such as Sand, Gravel, etc.
AN evenly distributed load may be end-tipped if the body be mounted so that more than half of it overhangs the tipping centre of body hinge. The load is tipped by releasing a pin in front and the body is pulled back to its original position by hand.
The rear overhang of the body, or part of the weight of the load, is utilized to reduce the amount of force necessary to raise the body when the lorry has an elevating screw in-front. Moreover, it is an advantage for the screw to be as near the body hinge as practical considerations allow, because the shorter this base line the larger the tipping angle with the same amount of lift.
Although the amount of rear overhang must be . limited, because it is not directly supported by the chassis,
and to meet legal requirements, the•tipping body as a whole, particularly
the bottom framework, must be more rigid than the fixed one. The tipping body has to be self-supporting and strong enough to resist the thrust of the tipping gear.
Metal construction is particularly suitable for tipping bodies and is a means for saving weight. Even if the greater part of the body be of wood, the longitudinals of the bottom frame should be of metal.
An angle of 45 degrees will tip mast loads effectively. Variations from this angle increase or decrease the rate of discharge, which is also deter
13.26 mined by the nature of the load, that is. whether it moves easily or otherwise. Other factors are the distance that the load has to travel for complete discharge and the material used for lining the body.
Thus, a side-tipper requires about 10 per cent, less tipping angle than an end-tipper, whilst a metal body, or a wood one lined with metal, is 1020 per cent, more efficient than one with a wood floor and sides.
When the body is lifted from underneath, as with an hydraulic ram and some patterns of gearing, it is raised close to the centre and a comparatively short travel of the tipping mechanism effects discharge, be
cause of the short distance to the body hinge. The rear wings of an end-tipper should lift with the body, so that the crown of the wing may be firmly secured, For end discharge, the tailboard is hinged from the top and swings clear by gravity, or it may be lifted by mechanism working in conjunction with the tipping of the body. If the tailboard, or part of it, be hinged at the bottom, it is utilized to throw the load clear of the back of the vehicle.
For side discharge, similar variations of hinging the outlet door are adopted. Hinging at the bottom is usually preferred. If there be a separately hinged upper portion of the side, this is used to control the rate of discharge, whilst a fixed rail along the top increases the strength' of the body.
Tipping vehicles are used chiefly for carrying road and building. material, also road and house refuse. With the last-named, the body is designed not only to tip, but also for dustless loading. In some instances, the body has a movable partition so' that the refuse may be packed to the front, in order that the canacity of the vehicle may be fully utilized.
A refuse wagon of this type is endloaded and has a box-pattern body. Instead of employing a moving partition, the load may be concentrated, when desired, by tipping the body forward. A suggested design has a rounded front, which is mounted at the centre, on brackets secured to each side of the chassis.
The mounting of this part of the body is facilitated by making it narrower than the rear portion, to which it is joined by sloping sides. When the bodN.is to be tipped forward, the rear body hinge is disengaged, so that the lifting gear may turn the body on its front centres. When the fully laden body is to be tipped in the usual manner, the front bearings are disengaged and the pins, or other fastenings, inserted in the rear hinges.
A self discharging wagon is one which has a sloping floor and does not require any tipping mechanism, such as is used for carrying grain in
bulk. This kind of body is also suitable for the transport of coal and road material.
The sloping floor is the full width of the body, with or without partitions, and the load is discharged on only one side. if the load is to be kept dry, the body is of the box pattern and it is filled through roof hatches, . The upper part of the sides is fixed and the lower part opens into two or more portions, to form a continuation of the sloping floor.
If a longer chute be required, the hinged portion is made higher than the opening and, therefore, overlaps the fixed upper part when closed. To control the discharge, side guards are necessary. These may consist of a pair of inner doors or flaps of the same size as the opening, and hinged so that they fold o n e upon the other cony eniently when closed.
A body with a full-width sloping floor has less capacity than one with a flat floor, but the accommodation is increased if it has a central longitudinal partition and the floor is in the form of an arch, so that it slopes on each side of it.
Another method of increasing the loading space is to hinge the floor so that part of it forms a slope only when the wagon is being unloaded. The floor sections, between the bearers, drop between side guards and the angle thus obtained depends on the height of the floor above the chassis when in its normal position. The hinged floor has the advantage that, with hinged extensions, the point of discharge may be close to the ground, also the sides of the body are fixed.
The self-discharging wagon is also made with the lower part of the sides sloping inwards, so that the load may be delivered through central trap doors at the bottom.
An ingenious vehicle of this kind was seen last November at Olymnia, B27