1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166 
STANDARDIZATION
Page 80
Page 81
If you've noticed an error in this article please click here to report it so we can fix it.
TO remark that, as quantity production of any article goes down, whether or not quality goes up, price almost certainly will increase is as true of commer:ial vehicles as of any other product. Indeed, generally ;peaking, commercial vehicle manufacturers have followed the pattern of grouping for larger quantity production. On the other hand, municipal transport has tended to remain highly specialized, since it has to meet clearly defined requirements laid down by widely differing local authorities. Sales are thereby restricted to small numbers, making a degree of compromise necessary between fitness for purpose and initial outlay. Thus, manufacture of such machines has often been left to specialist bodybuilding firms willing to take a chassis, modify it where possible to suit the municipal need, and build on it a body which, though not necessarily a "one-off special" is at all events made in small numbers with many variations. It is, therefore, a little difficult to reduce the price of such vehicles.
Operating conditions in most municipal undertakings are arduous. Refuse collectors must gain approach to every dwelling, whatever the road surfaces or gradients; continual stopping and starting is normal with attendant possibilities of the engine not warming up properly, the generator not charging batteries sufficiently, high fuel consumption, starter-gear wear, and so on. Travelling over the face of a rubbish tip is not kind to any chassis, particularly if" tipping right over the edge" is practised. There has, in fact, been a tendency (mercifully now diminishing) for a tipped vehicle to be reversed against the load to act as a bulldozer. The constant presence of fine ash and dust may bring other problems; these abrasives are readily capable of turning lubricant grease into a form of grinding paste!
There are various features of municipal service to which the normal operational criteria do not apply. Fuel consumption on refuse collectors and gully emptiers is an obvious example. Tyre wear is another, since more tyres are cut to pieces by tip work than are worn out by tread wear. Maintenance schedules based on mileage are dangerous since they could well mean, for example, changing oil at very long intervals whereas the nature of the job makes frequent changes desirable.
From considerations such as these, it follows that various items merit special attention in a municipal vehicle design. Relating to the engine, these include filtration, cooling, exhaust position, noise level and sump height. In the transmission, a heavy duty clutch and robust gearbox are essential and final-drive ratios may well differ from those on commercial vehicles doing general haulage work. A low loading height is usually an advantage, although the chassis designer has also to bear in mind the question of sufficient ground clearance for off-the-road work. On the electrical side, large generators and batteries are called for and care is needed in wiring layout to prevent troubles from dust and moisture. External projections in general have to be avoided, particularly at the operational end of a refuse vehicle where they will have a short life indeed. It is often an advantage to specify tyres with side lugs for tip work and off-road conditions generally.
Basic requirements today for a successful municipal machine are fitness for purpose, reliability, safety and economy. The first of these implies a down-to-earth practical design approach. The second means long periods of wearisome development work, tests, adjustments and further tests before production, plus an obsessive determination to provide for parts and service units being available immediately they are wanted. Safety considerations will again call for special attention during development and test operations. Economy refers to overall cost of the undertakings' service and depends far more on the success of the design than on initial outlay.
The manufacturers and bodybuilders are bound to ask themselves how these different and opposing demands can possibly be reconciled. "One-off specials " do not give much scope for long and patient development (still less do they make it easy to provide 100 per cent. spares service) and a service unit exchange scheme cannot readily be provided. Above all, how on earth is it possible for a manufacturer to achieve economy in production under such limiting conditions? His firm will obviously need a big proportion of highly skilled draughtsmen and fitters, the outlay for materials and work in progress will be high, and material supplies will need extremely careful planning.
The problem is one when analysis, statistics, a certain amount of compromise and a good deal of engineering ingenuity are obviously needed by any bodybuilder or manufacturer. It would be wrong to suggest that there is any one complete answer but a logical approach can be adopted, if the customers accept it. The cab must receive careful thought, for instance. A basic cab should be of reasonably simple, effective and practical design with the emphasis on ease of access. An extended version with crew compartment will be required for refuse collecting vehicles. A further extension may be necessary to provide a sufficiently large cab to embody a workshop for such machines as breakdown vehicles and street lighting service vehicles.
It is, however, in the design of the bodywork that most problems arise when seeking to achieve a measure, at least, of rationalization. It is obvious that more than one size of body will be needed and the approach may be for a manufacturer to make two or more lengths with the working parts similar, one body being merely a longer version of the other. To suit the most diverse local authorities, both at home and overseas, with one and the same vehicle is, perhaps, an unattainable ideal; but much may be achieved by making various items interchangeable at the " business end" of the machine.
The first essential is that the basic vehicle should be adequate, that is to say it must be able to load and compress refuse continuously without any attention from the crew, whatever is put in and however fast the rate of loading. Open discharge of ordinary bins is not nowadays readily acceptable and so various expedients have been adopted to minimize dust and litter nuisance during loading.
Throughout the design stages, it has to be borne in mind that vehicles now being pit into service may be operational for the next 10 years or so, and planning should allow for modification or conversion to automatic loading systems should the operator wish to have this done during the life of the machine.
During a survey of the usage of different sizes of bin, it was found that in Scotland and on the Continent bins of 11 cu. ft. capacity were common. For these, it is possible to provide enclosed shutters with hand operation. For the 2.5 cu. ft. and 3.2 cu. ft. bins most common throughout the U.K. and Commonwealth countries power operation is probably the best line of development.
Various overseas, and particularly Continental, designs have been adapted for operation in the U.K. It is, however, unsafe for an operator to assume that equipment giving satisfactory service overseas can automatically be imported and put to work by local authorities here. Possibly it can, but also the case may be that many local factors, some of them not readily apparent, may bring about the need to carry out quite a lengthy development programme. For example, in some countries it is the practice to use small bins which are housed indoors, whilst in the United Kingdom it is usual to have large bins kept out of doors. This affects the size and nature of items finding their way into the bin and, of course, the speed with which loading can be carried out.
It is well known that in districts where a great deal of coal is burned the proportion 8f ash and clinker is high.
The amount of coal burned in open hearth fireplaces is now diminishing; in Continental countries it is already much less. There are also widely diverging notions as to what can be classified as normal refuse to be dealt with by the local authority. In some places it is traditional to accept almost any household item that arises (including worn-out furniture, mattresses and such things as iron bedsteads). Overseas practice may well be to require such objects to be dealt with in some other way.
Refuse in many areas tends to be lighter and bulkier. If the weekly collection method is to be maintained, and this does represent the broad average in this country, it seems reasonable to suggest that some system, of poweroperated enclosed loading is desirable. This will make the job far less tiring and unpleasant and bring the work of the refuse collector more in line with that of the other house-to-house callers such as the milkman and the baker. The possibility of light, functional plastic bins being available in future years ought not to be overlooked.
Wherever large quantities of waste are produced, it is logical to install bulk containers and use power equipment for discharge. Here is an instance where the question of gradual introduction of such systems arises, since it is highly unlikely that in the early stages a vehicle will be engaged full-time on this particular work. A quickly detachable set of equipment might be an advantage. Normally the refuse collector crew are hampered by the presence on the rear of a compression vehicle of such sub stantial and robust lifting mechanism as is needed for these bulk containers. It may be that a few minutes spent at the depot removing the gear altogether are amply repaid by speed of working with a completely free hopper after container work has been finished. Some ingenuity is needed in supplying hoist equipment able to deal with the various types of bulk container that have come into use in this country and others; it has to be simple, strong and easy to adjust.
Paper bag schemes of refuse collection have introduced a new element, but one with which basic automatic loading vehicles are very well capable of dealing. Power-operated enclosed loading continues to make progress, particularly where refuse is heavy or where the ash content is high.
Here then, have been mentioned just a few of the many problems that arise specially with regard to municipal vehicle design, all of which impinge on the degree of standardization that can be achieved. A lot may not be possible, but some degree certainly is attainable.