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
167
168
169
170
171
172
173
174
175
176
177
178 
i t ' s worth it! BY ERNEST ALLEN
Page 87
If you've noticed an error in this article please click here to report it so we can fix it.
a tug with the tractor to ensure a safe couple up. The very fact that the trailer does not move will confirm the security of the coupling and also tend to satisfy the driver that his handbrake is effective as well. He can, however, miss one very important fact; that it may not be the handbrake that is holding the trailer but, in fact, the trailer is being held by its own air pressure and will remain so held until pressures are equalized by the tractor pump.
The fact that the hand lever is travelling to its limit may not trouble him unduly. Only if the trailer air system is up to full pressure or fully blown off can the driver be sure that his trailer brakes are off and the handbrake test is a truthful one. Many drivers couple up air lines and use the hand air control for the coupling test, with no real regard for the parking brake. However, attention is now focused upon this parking brake by the Ministry of Transport and the police, and it is necessary to draw attention to the correct handbrake test procedure.
Surprisingly enough, and despite its now involved lay-out, the electrical system does not give much trouble other than pulled-out supply leads or damaged tail lamps; with the advent of more lights and flashers, the driver automatically draws early attention to failed bulbs, and so on, and this section of the trailer does not get out of hand. Similarly, one driver will soon draw the attention of another to some unlit lamp, whether tail, stop, flasher or marker; therefore, we have the driver more than interested.
Hose Problem Air lines and the lighting lead are something of a problem on certain tractors, because of varying height of cab, and lines can become caught up on tank neck or tractor platform edge unless tidily maintained. However. a new line is on the market called Susies ", a spiral hose for air or electrical use that stretches and returns, removing the problem mentioned. But these lines are not as yet suitable for vacuum systems.
Let us now examine certain other causes of failure that concern the engineer, adding to his maintenance problems,
and which affect equipment availability. This time I would refer to operating conditions and the hazards that bring their own quota of repairs. Probably number one on the engineer's black list will be the aftermath of a dropped semi-trailer. A vast number of words have passed to and fro on this particular repair feature and its several causes, and it should be made clear right away that, whatever the make of coupling, it will not release the trailer unless badly neglected, carelessly coupled, or interfered with.
Strangely enough, neglected coupling maintenance is Again the answer is in the regular wash off and inspection; this will ensure that there is no unobserved build up of trouble.
A known cause of dropped trailers is the dangling rope end. This can enter the jaws or jaw wedge and can be sheared off, remaining out of sight but preventing the jaws closing fully round the pin, or the wedge going fully home to lock them. However, the final locking lever should indicate to the driver that something is wrong, and it is most important that the locks are inspected before driving off.
Drivers should not rely on the fact that in 99 instances out of 100 the coupling can be made automatically and successfully. This fact has been proved many times, and where an obstruction such as a rope end has been the cause of a dropped trailer it has inevitably come to light that no full inspection was made of the locking mechanism.
Not Coupled A further cause of a mis-couple can occur where the trailer has not climbed the tractor ramp to the coupling, but has been standing too high and the collar of the trailer pin has not gone below the jaws but has dropped on to them from above. The trailer is then being pulled along the road by no more safe a connection than the larger diameter of the pin collar located in the turntable aperture. the first upward lift of the trailer head releasing it from the tractor. This incident, however, rarely happens in the daytime, as this form of mis-couple would be easily observed. It is, unfortunately, a night incident often during some roadside change-over.
The final cause of a dropped trailer is unauthorited interference. This sometimes happens in city parks, cafes. and so on, and usually means that some person has lifted and moved the first release lever. If they did stay to watch the tractor drive away and leave its trailer behind they would be disappointed, as it would be two to three miles farther on when the sliding lock finally released the jaws and the trailer dropped. Again this has been proved beyond doubt; reliable and interested drivers have inspected their equipment after a meal and have found the release lever in the unlock position, also noting one or more interested observers across the street. Although this matter has been reported to the police on one or two instances, proving just who moved the lever in the driver's absence is an impossible task.
• There is only one reliable solution; in all instances oi leaving and returning to articulated equipment, carefully examine locking leers before moving off.