Safety rail for vehicle catwalks

A safety rail assembly for a vehicle catwalk comprises a rail pivotally connected to the vehicle. The rail is movable by rams from a storage position lying across the catwalk to a raised operative position. The rams are connected to the vehicle pneumatic brake system so that the vehicle brakes are continuously in operation while the rail is raised.

The invention relates to a safety rail assembly for a vehicle catwalk. The 
term "catwalk" as used in this specification refers to the footway along 
the top of a vehicle body such as, for example, the footway along the top 
of a tanker body giving access to openings into each of a number of tank 
sections. 
In a vehicle such as a tanker the tanker body is usually divided into a 
number of tank sections each carrYing a quantity of liquid therein. To 
check the contents of each tank section a calibrated dip stick is inserted 
into the tank through an access opening on the top of the tank. It is also 
necessary to enter the tank sections through these access openings from 
time to time to carry out maintenance checks on each tank section. A 
catwalk is usually provided along the top of a tank adjacent the access 
openings to provide a platform from which each tank section can be dipped. 
As can be appreciated, when using the catwalk it is relatively easy to 
lose one s footing, especially in cases where some of the liquid cargo or 
rainwater has fallen on the catwalk and/or where the catwalk is used in 
windy conditions or, indeed, if the vehicle is started up. Indeed there 
have been a number of accidents where persons have fallen from the catwalk 
of a vehicle and sustained serious bodily injury. 
There is therefore a need for a safety rail to help prevent accidents when 
using a vehicle catwalk. 
The present invention is directed towards providing such a safety rail. 
According to the invention there is provided a safety rail assembly for a 
vehicle catwalk comprising a rail and actuating means to move the rail 
from a stored position to a raised operative position. 
Ideally, the rail is pivotally mounted for movement about a pivot axis 
between the stored and operative positions. 
Preferably, the pivot axis extends substantially parallel to the 
longitudinal axis of a vehicle catwalk. 
In one embodiment, in the stored position the rail overlies at least 
portion of the catwalk. 
In another embodiment, the rail includes an accessory blocking portion 
which, in the stored position projects beyond the catwalk adjacent an 
access way to the catwalk to prevent access to the catwalk unless the rail 
is in the operative position. 
In a further embodiment, the assembly includes a locking means to rigidly 
secure the rail in the stored and/or operative position. 
In one aspect of the invention, the rail includes an access opening 
blocking portion which, in the stored position lies across access openings 
to the vehicle body when the rail is in the stored position preventing use 
of the access openings unless the rail is in the raised operative 
position. 
In a preferred embodiment, the actuating means comprises a ram means. 
Preferably the ram is in the extended position when the rail is in the 
stored position. This is to ensure that the rail is retained in the stored 
position when the vehicle is in motion. 
In this latter embodiment, the ram means is preferably pneumatically 
operated from the pneumatic system of a vehicle. 
Preferably, the ram means comprises at least one ram extending between the 
rail and the vehicle. In one aspect, the ram means comprises a plurality 
of spaced-apart rams. Ideally, the or each ram is located adjacent the 
pivot axis of the rail. 
In another aspect, restricted exhaust valves are provided for the ram means 
to prevent the rail from lowering dangerously quickly. 
In an alternative embodiment of the invention, the ram means is 
hydraulically operated. 
Preferably, the assembly includes operating means located remote from the 
rail for operating the actuating means. 
Preferably, the assembly includes remote indication means to indicate the 
position of the rail. 
In one aspect of the invention, the assembly includes cut-out means to 
prevent the vehicle from moving if the rail is in the raised operative 
position. 
In this latter embodiment, the cut-out means preferably operates to engage 
the vehicle brakes when the rail is raised to prevent operation of the 
vehicle brake control system while the rail is raised. 
Preferably, the cut-out means comprises a brake valve operated by the 
actuating fluid of the actuating means to operate the vehicle brakes when 
the ram means are actuated. 
Ideally, the brake valve is interposed between the vehicle brake control 
system and the vehicle brakes to prevent access of the brake control 
system to the brakes when the ram means are activated. 
In these latter two embodiments, the actuating fluid is preferably air from 
the vehicle pneumatic system. 
In one embodiment, the brake valve is a shuttle valve. 
Alternatively, the cut-out means operates to urge the rail into the stored 
position when the vehicle brakes are disengaged. 
In this latter alternative embodiment, the actuating means are disconnected 
from the actuating fluid when the vehicle brakes are disengaged.

Referring to the drawings and initially to FIGS. 1 to 3, there is 
illustrated a safety rail assembly for a vehicle catwalk indicated 
generally by the reference numeral 1. The rail assembly 1 is shown mounted 
on a tank 2 forming part of a tanker. The tank 2 is of conventional 
construction being internally divided into a number cf separate 
compartments each having an entrance thereto by means of a removable cover 
3 located at the top of the tank 2. Access to the covers 3 is provided by 
a catwalk 4 supported on a frame 5 and mounted along the top of the tank 
2. A ladder 20 is mounted at one end 19 of the tank 2 for access to the 
catwalk 4. 
The safety rail assembly 1 comprises a tubular rail 6 pivotally mounted to 
the frame 5 for pivotal movement about a pivot axis and actuating means to 
pivot the rail 6 from a stored position in which it lies across the 
catwalk 4, see FIG. 3, to an upright operative position as shown in FIGS. 
1 and 2. 
The rail in this case comprises five spaced-apart stanchions 9 which are 
pivotally connected at the lower ends thereof by a pivot pin 10 to 
brackets 25 welded to the frame 5, the pivot axes defined by the pins 10 
being co-linear and extending substantially parallel to the longitudinal 
axis of the tank 2. It will be noted that the rail 6 is mounted at one 
side of the catwalk 4 and extends the full length of the catwalk. An upper 
longitudinal rail member 26 and connecting rail members 11 extend between 
the stanchions. Buffer means to buffer the movement of the rail 6 over the 
catwalk 4 is provided by three anti-vibration buffer pads 12 which in this 
case are mounted to the upper longitudinal rail member 26. The buffer pads 
12 are pivotally mounted to the rail member 26 so that they hang down 
unobtrusively when the rail 6 is in the raised operative position 
illustrated in FIG. 1. As the rail 6 moves towards the stored position the 
pads 12 are interposed between the rail 6 and the catwalk 4. 
The actuating means for moving the rail 6 between the stored and operative 
positions in this case comprises five pneumatic ram means 7, one 
associated with each stanchion 9. Referring particularly to FIGS. 2 and 3 
each ram means 7 comprises a ram 13 and associated cylinder 14 having a 
through hole 16 to the inside of the cylinder to which an air supply, 
usually from the pneumatic system of a vehicle, is connected. The ram 13 
is pivotally connected at 27 to a bracket 8 mounted on the stanchion 9 and 
the cylinder 14 is pivotally connected at 28 to a bracket 29 which in this 
case is welded to the tank 2. 
Referring now to FIG. 4 the connection of four of the ram means 7 to the 
vehicle pneumatic system is illustrated in more detail. The lower through 
holes 16 of each of the ram means 7 are connected by actuating air lines 
50 to a rail control valve 52 which is, in turn, connected to the vehicle 
pneumatic system by a air line 59. The ram means 7 are connected at their 
upper ends to the rail control valve 52 by de-actuating air lines 55. The 
rail control valve 52 includes a user-adjustable knob 56 which is suitable 
for mounting inside a vehicle cab, and a pair of restricted exhaust valves 
57. One of the actuating air lines 50 is also connected to a safety 
pressure regulator valve 58. In this case, the user-adjustable knob 56 is 
mounted in the vehicle cab. 
Cut-out means are provided in this case by a brake shuttle valve 51 
interposed between the vehicle's brake control system 54 and the actuating 
air lines 50 on one side and the vehicle brakes 53 on the other side. 
In use, the rail 6 is normally maintained in the stored position as shown 
in FIG. 3. The rail 6 is stored against the vehicle to reduce windage when 
in transit and to keep the height of the vehicle to a minimum. The rail 6 
is retained locked in the lowered position by the rams 7 which are 
extended when the rail is in the lowered position. When it is necessary to 
use the catwalk 4, the user operates the knob 56 of the rail control valve 
52 to pressurise the actuating air lines 50 and thereby actuate the ram 
means 7 and to raise the safety rail 6. In addition to actuating the ram 
means 7, the air pressure in the actuating air lines 50 also switches over 
the brake shuttle valve 51 and activates the vehicle brakes 53. In this 
position, the brake shuttle valve 51 effectively disables the vehicle 
brake control pneumatic system 54. In this case therefore, the vehicle 
brakes are immediately applied when the safety rail 6 is raised and the 
brakes can not be disengaged as long as the rail 6 is raised. The user 
then climbs onto the catwalk 4 and uses the rail 6 as a support. After 
descending from the catwalk 4, the user again operates the knob 56 to 
change-over the rail control valve 52 to cause the de-actuating air lines 
55 to be pressurised. Exhaust air is transmitted by the actuating air 
lines 50 to the restricted exhaust valves 57. The brake shuttle valve 51 
then switches to allow operation of the brake control system. As the 
exhaust valves 57 are restricted, the safety rail 6 does not lower 
dangerously quickly. 
In this case the movement of the rail between the operative upright and 
stored collapsed positions is buffered by maintaining pressure in the 
cylinders of the rams. This prevents the rail from moving dangerously 
quickly. In addition, it ensures that the rail resists wind forces when 
the tanker is in motion which might tend to lift it. The configuration of 
the rams so that they are extended when the rail is in the collapsed 
position is important in this respect in ensuring that the rail is 
effectively locked in the stored position. 
It will be appreciated that while it is preferable to use the operating 
fluid to buffer the operations of the rail alternatively or additionally 
anti-vibration buffer pads may be freely pivotally mounted to the rail so 
that they hang downwards unobtrusively when the rail is in the raised 
position and are interposed between the rail and the catwalk when the rail 
is moved to the lowered position. 
While the rams and the pivot arrangement generally may be provided at any 
suitable location it is preferred that the rams be arranged on the side of 
the rail opposite the catwalk. This is a safety precaution to ensure that 
there are no obstructions to an operator walking along the catwalk. 
It will be appreciated that the above described pneumatic system provides 
for safe use of the catwalk 4 as the vehicle brakes are continuously in 
operation as long as the safety rail is raised. Further, as restricted 
exhaust valves are provided, the rail may not lower dangerously quickly. 
It will further be appreciated that there is little chance of faults 
occurring in the brake and safety rail operation due to the pressure 
regulator safety valve 58. 
Referring now to FIGS. 5 and 6 there is illustrated another safety rail 30 
according to the invention being cf largely similar construction to the 
safety rail assembly 1 and like parts are assigned the same reference 
numerals. The only difference in construction is that in this case the 
rail 6 of the safety rail assembly 30 has an extended portion, in this 
case comprising a U-shaped tubular bracket 31, mounted on an end stanchion 
9 of the rail 6 and extending over the end 19 of the tank 2. When the rail 
6 is in the stored position as shown in FIG. 6 the bracket 31 projects 
over the top of the ladder. 20 preventing access to the catwalk 4 when the 
rail 6 is in a stored position. It is necessary to pivot the rail 6 into 
the upright position to have free access to the catwalk 4. 
Referring now to FIG. 7 there is illustrated another safety rail assembly 
40 according to the invention. Again this is of largely similar 
construction to the safety rail assembly 1 and like parts are assigned the 
same reference numerals. In this case the rail 6 is constructed such that 
the upper longitudinal rail member 26 will lie over the covers 3 leading 
into the compartments of the tank 2 when the rail 6 is in the stored 
position as illustrated. This ensures that the rail 6 must be pivoted into 
the upright position before opening any of the covers 3 for access to the 
tank compartments thus ensuring that the rail 6 is in the upright position 
whenever the catwalk 4 is used. Further, the rail 6, when in the stored 
position prevents unauthorised access to the compartments of the tank 2. 
The invention provides a convenient support when using the catwalk, 
reducing the possibility of accidents occurring when using the vehicle 
catwalk especially since the safety rail can not be used unless the 
vehicle is stationary. 
It will be appreciated that many different constructions of rail are 
possible without departing from the scope of the invention. Thus, the rail 
assembly may have locking means for locking the rail in either one of the 
stored or raised positions, and there may be remote indication means for 
indicating the position of the rail. 
It will be appreciated that the safety rail assembly may be of any suitable 
material of construction.