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 
IN YOUR OPINION
Page 134
If you've noticed an error in this article please click here to report it so we can fix it.
Handbrake—a third alternative I FULLY agree with Mr. Walkden's letter regarding the need for power assistance on vehicles of 20 tons g.v.w., but the handbrake, although generally regarded as a brake to be used for parking or in an. emergency, must be a satiSfactory brake, and to do this must be available always at full power.
It is possible, for instance, for a minor accident to damage piping, reservoirs, etc., and put the pressure or vacuum servo out of action, and I know of at least one serious accident which occurred through this reason.
Mr. Walkden says there are two ways of solving the problem, either a multi-pull handbrake or power-assisted single-pull. The multi-pull handbrake can never be really satisfactory as it incurs delay and a split second may make all the difference between safety and danger in an emergency. Furthermore, no one has yet devised a normal servo assistance which is not itself liable to failure.
There is, however, a third alternative which Mr. Walkden does not mention. When a handbrake is released an idle stroke is used. This could be made a power stroke to compress a spring and store energy for the application stroke, and this combined with an efficient variable ratio should give all the power required without the complication of other servo assistance. It is, of course, really a powerassisted brake but not in the generally accepted sense as the power is provided by the driver.
There is also another advantage in this, system in that the brake can be applied very quickly indeed as it tends to move to the " on " position and cannot be easily released by a child or mischievous person if the vehicle is parked on a hill. It also enables easy take-off if the vehicle is halted by traffic or lights when proceeding up a hill.
Crookham, Hants. J. DAVEY.
The Safest on the Road THEoriginal heading to this correspondence was" Saving 'THE on the Roads ", which is still my main object. " People are more important than traffic ", says Sir William MO Holford. I wish there were many more "interested spectators" like Mr. M. D. Bush (The Commercial Motor, January 3I)—we might get somewhere then. The chief constables he refers to are merely expressing their own opinions, but no statistics are offered. Probably many people take an entirely opposite view.
Ten years ago there were no better ;tor more considerate drivers than the "heavies "—they were indeed the knights of the road ". Their speed limit then was .20 m.p.h. and they stuck to it. Now, at double the speed, they are reitless and go still faster at every opportunity they get, especially in this district. Mr. Bush, at 40-50 m.p.h., could not possibly keep up with them.
The Government view, as opposed to that of some chief constables, is "that on the basis of distance travelled the casualty rate among goods vehicles' occupants increased markedly between 1961 and 1962" (Road Accidents, 1962, H.M.S.0.). The injulies to pedestrians and occupants of other vehicles must also be increased as a complementary result. Again: "For fatal accidents alone the involvement rate of goods vehicles of more than 1 tons is noticeably higher than that of cars and light goods vehicles—this was a larger percentage increase than for any other class of road user and there was no comparable increase in total goods mileage ". The publication continues: "Though involved in fewer accidents per mile travelled than light vehicles and cars a higher proportion of those in which they (goods vehicles) are involved are severe ".
I have spoken to some of the older drivers; they say, "Things ain't what they used to be." I foresee much of our essential goods traffic going by air—we will all be high flying then!
I much appreciated the excellent letter from Mr. H. Walkden referring to power-assisted handbrakes. These would save many crashes and lives. And the law would be complied with.
MeIksham, Wilts. E. V. HUMPHREY, WG. CDR.