Collapsible tank trailer railing

A modular collapsible tank trailer railing assembly for connection to a catwalk on the top of a tank on a tank trailer, the modular collapsible tank trailer railing assembly including a base member connected to the catwalk, an upper rail, a middle rail located between the upper rail and the base member, a plurality of posts pivotally connected to the base member, the middle rail, and the upper rail, a handle for rotating one of the plurality of posts to raise and lower the upper rail and the middle rail, and a spring for biasing one of the posts toward the upright position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to tank trailer or tank truck walkways. In 
particular, the invention relates to walkways on the top of tank trailers 
towed on highways by tractors and tank trucks driven on the highways of 
the United States. 
2. Description of the Related Art 
Tank trailers pulled by tractors on the highways of the United States are 
used to transport a large variety of fluids, including chemical compounds 
in a liquid or gaseous states. Such tank trailers have a walkway which is 
commonly referred to as a "catwalk" on the top thereof which does not have 
a railing to prevent personnel from falling. Permanent railings on top of 
the tank could strike bridges, overpasses, or other objects under which 
the tank trailer may travel. 
The catwalk is commonly used on tank trailers to enable personnel to open, 
close, or inspect the hatch commonly found on top of the tank. Such 
catwalks pose a safety hazard to personnel utilizing the catwalk. Many 
serious injuries have been incurred by people falling from tank trailer 
catwalks. 
Exemplary of the Patents of the related art are the following U.S. Pat. 
Nos. 723,312; 836,372; 1,816,028; 4,371,056; 4,759,437; 4,936,407; 
5,071,166; and 5,237,932. 
SUMMARY OF THE INVENTION 
In accordance with the present invention there is provided a modular 
collapsible tank trailer railing assembly for connection to a catwalk on 
the top of a tank on a tank trailer, the modular collapsible tank trailer 
railing assembly including a base member connected to the catwalk, an 
upper rail, a middle rail located between the upper rail and the base 
member, a plurality of posts pivotally connected to the base member, the 
middle rail, and the upper rail, a handle for rotating one of the 
plurality of posts to raise and lower the upper rail and the middle rail, 
and a spring for biasing one of the posts toward the upright position. 
The present invention can be built in modular form for easy installation on 
catwalks of various sizes to minimize tank trailer downtime during 
installation of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, in FIGS. 1-3 is shown the modular 
collapsible tank trailer railing assembly of the invention generally 
indicated by the numeral 10. Collapsible tank trailer railing assembly 10 
has an upper rail assembly generally indicated by the numeral 12 pivotally 
connected to the tops of a plurality of pivotal post assemblies generally 
indicated by the numeral 14 by a plurality of pivot brackets 16. A rigid 
elongated one-piece middle railing 15 is pivotally connected to the 
approximate middle of post assemblies 14 by pins 15a. 
The bottoms of the post assemblies 14 are pivotally connected to the 
railing base member generally indicated by the numeral 18 by a plurality 
of nut and bolt assemblies generally indicated by the numeral 20. The 
middle of post assemblies 14 are pivotally connected by the rigid middle 
railing 15. Railing base member 18 is rigidly connected to the catwalk 
generally indicated by the numeral 22 by nut and bolt assemblies 20. 
A handle assembly generally indicated by the numeral 24 pivotally connected 
to railing base member 18 is rotated in the direction indicated by the 
arrow 26 in FIG. 1 to lower or collapse collapsible trailer railing 
assembly 10 to the position shown in FIG. 2. A lever arm assembly 
generally indicated by the numeral 28 pivotally connected to railing base 
member 18 spring loads the post assemblies 14 and upper rail assembly 12. 
Lever arm assembly 28 rotates in the direction indicated by the arrow 30 
in FIG. 1 when handle 24a rotates in the direction indicated by the arrow 
26 in FIG. 1. 
Catwalk 22 is connected to the top of the tank generally indicated by the 
numeral 25 by any suitable connectors known in the art. Tank 25 is a 
liquid tank connected to the top of a trailer or truck having a hatch 25a 
shown in phantom lines for adding fluids thereto. Tank 25, when mounted on 
a trailer, is towed by a motor driven tractor on roads and highways. Such 
tractor and trailer combinations are well known in the art and are 
commonly referred to as "eighteen wheelers". 
Catwalk 22 may be used on some tank trailers to enable personnel to attend 
to the top of the tank 25, or to open, close or inspect hatch 25a, and the 
like. Exemplary of a trailer having a tank thereon for towing on the 
highway by a tractor is the tank trailer shown in U.S. Pat. No. 1,816,028, 
which is hereby incorporated by reference. 
Referring now to the components of the collapsible tank trailer railing 
assembly 10 in greater detail, upper rail assembly 12 can be seen to 
preferably have two identical hand-holds 34 and 36 thereon for grasping by 
the user to assist in pulling the collapsible tank trailer railing 
assembly 10 to the upright position when the user is standing on the 
catwalk 22. Preferably hand-holds 34 and 36 are hollow aluminum tubing 
rigidly connected to upper rail assembly 12 by bolts or rivets 34a--34a 
and 36a--36a, respectively. 
As can best be seen in FIGS. 3 and 4, upper rail assembly 12 includes an 
elongated rigid U-shaped channel 12a having two inwardly turned lips 
12b--12b in the open side thereof which hold a plurality of nuts 12c 
therein. The sides of nuts 12c contact the inside of the sidewalls 12d and 
12e of channel 12a when bolt 12f is threaded therein and are thereby 
prevented from turning. Each nut 12c is held against lips 12b--12b by a 
spring 12g. U-shaped channel 12a is well known in the art and is preferred 
for ease of construction. However, if desired, a tubular metal channel 
having a rectangular cross section could be used to replace U-shaped 
channel 12a. 
Connected to the bottom of channel 12a adjacent to lips 12b--12b is an 
elongated flat metal strip 13 having a rectangular cross-section. Strip 13 
is connected to channel 12a by bolts 12f which extend through channels 
16a--16a in pivot bracket 16. Pivot bracket 16 has a second channel 16b 
therein for pivotal receipt of bolt 40. 
As can best be seen in FIG. 3, post assembly 14 includes two identical 
posts 14a--14a. The upper ends of posts 14a--14a are separated by pivot 
bracket 16 which is pivotally connected to posts 14a--14a by bolt 40 and 
nut 40a. The approximate mid-point or middle of posts 14a--14a is 
separated by middle railing 15 which is pivotally connected to posts 
14a--14a of each post assembly 14 by a pin 15a. The lower ends of posts 
14a--14a are separated by a hollow cylindrical sleeve 20a which receives 
bolt 20b of bolt assembly 20 therein. 
Bolt 20b extends through the railing base member 18. As can best be seen in 
FIG. 3, railing base member 18 has a generally U-shaped cross-section 
including a base 18a having an inner side 18b and an outer side 18c 
extending perpendicularly upward therefrom. Outer side 18c extends upward 
above the catwalk 22 a distance sufficient to contact the foot or toe of a 
person standing on catwalk 22 to help prevent a person from stepping off 
of the catwalk 22 and falling from the catwalk when the modular 
collapsible tank trailer railing assembly 10 is collapsed as shown in FIG. 
2, or raised as shown in FIG. 1. Preferably, outer side 18c extends at 
least four inches above the top 22a of catwalk 22 to comply with current 
United States government standards. 
The catwalk 22 includes a plurality of elongated parallel brace members 
22b--22b connected to the top of tank 25 by welding, bolting, or the like. 
The brace member 22b closest to base member 18 is bolted thereto by bolt 
20b and nut 20c. Top 22a is rigidly connected to brace members 22b by 
welding, or the like. 
When the modular collapsible tank trailer railing assembly 10 is collapsed 
as shown in FIG. 2, the post assemblies 14 and the middle rail 15 fit 
completely into the channel formed by the bottom 18a and the sides 18b and 
18c of base member 18. 
In FIG. 5, handle assembly 24 is shown in detail. Handle assembly 24 
includes a handle 24a rigidly connected to a pivot member 24b having a 
channel therein for pivotal receipt of bolt 20b, and an arm 24c rigidly 
connected to pivot member 24b and extending longitudinally therefrom. As 
can be seen in FIG. 5 and in FIGS. 1 and 2, arm 24c is aligned between 
posts 14a--14a and bolted thereto by bolts 24d--24d and nuts 24e--24e. A 
spacer or hollow sleeve 24f may be provided for receipt of lower bolt 24d 
as shown in FIG. 5. Preferably, handle 24a, pivot member 24b, and arm 24c 
is integrally molded or formed from a single piece of rigid material. 
Handle 24a rotates in a slot 18d formed in the bottom 18a of base member 
18. 
As further shown in FIGS. 1, 2, and 5, a semi-circular plate 24g is rigidly 
connected to the bottom 18a of base member 18 by welding or the like and 
is aligned parallel to the side of handle 24a. Connected to the back side 
or tank side of plate 24g is a flexible arm 24h by bolts or pins 24i--24i. 
Rigidly connected to flexible arm 24h is a bullet-shaped protuberance 24j 
which fits through hole 24m in plate 24g and is selectively received in 
channel 24k in handle 24a to lock handle 24a in the position shown in FIG. 
1. A second hole 24p is located in plate 24g for receipt of protuberance 
24j when handle 24a is in the position shown in FIG. 2 to lock handle 24a 
in the position shown in FIG. 2. 
Lever arm assembly 28 includes lever arm 28a which is molded or formed from 
a single piece of rigid material and is outwardly shaped identical to the 
integrally formed handle 24a, pivot member 24b, and arm 24c. Lever arm 28a 
has a pivot member 28b, and an arm (not shown) identical to arm 24c 
aligned between posts 14a--14a connected to posts 14a--14a by bolts 
28d--28d. A coil spring 28e is connected to lever arm 28a and to bracket 
28f which is rigidly connected to base member 18. 
To collapse the modular collapsible tank trailer railing assembly 10 from 
the position shown in FIG. 1 to the position shown in FIG. 2, the handle 
24a is grasped by the right hand of the user and the flexible arm 24h 
shown in FIGS. 2 and 5 is grasped by the left hand. The flexible arm 24h 
is moved to the position shown in phantom lines in FIG. 5, thereby 
removing protuberance 24j from channel 24k in handle 24a. Referring to 
FIG. 1, as handle 24a is rotated in the direction indicated by the arrow 
26, post assemblies 14 rotate in the direction indicated by the arrow 41, 
and lever arm 28a rotates in the direction indicated by the numeral 30. 
The rotation of lever arm 28a stretches and extends spring 28e to the 
position shown in FIG. 2. Handle 24a is rotated until it reaches the 
position shown in FIG. 2, flexible arm 24h is aligned with hole 24p, and 
protuberance 24j is inserted through hole 24p in plate 24g and into 
channel 24k in handle 24a to lock handle 24a in the position shown in FIG. 
2. FIGS. 2 and 8 show flexible arm before it is moved into alignment with 
handle 24a to lock handle 24a in the collapsed position shown in FIG. 2. 
In FIG. 6 is shown a second embodiment of the invention in which a 
conventional pneumatic or hydraulic cylinder and piston assembly generally 
indicated by the numeral 42 is connected to handle 24a rotate handle 24a 
to collapse the modular collapsible tank trailer railing assembly 10 from 
the position shown in FIG. 1 to the position shown in FIG. 2. As is known 
to those skilled in the art, pneumatic or hydraulic cylinder and piston 
assembly 42 includes a cylinder 42a which forces a piston, having a piston 
rod 42b connected thereto, in cylinder 42a or out of cylinder 42a as 
indicated by the double pointed arrow 42. Cylinder 42a has two hollow 
lines 42c and 42d connected thereto for conveying air or hydraulic fluid 
thereto to force piston rod 42b in cylinder 42a in or out of cylinder 42a 
as indicated by the double pointed arrow 44. Cylinder 42a could be 
controlled by a switch mounted at a convenient location on the tank 
trailer or on tank 24. In the second embodiment of the invention, the 
lever arm assembly 28 and spring 28e could be eliminated. 
In FIGS. 7 and 8 there is shown a third embodiment of the invention in 
which a ladder generally indicated by the numeral 50 is placed at a 
desired location, such as in alignment with an existing ladder 51 shown in 
phantom lines on FIGS. 7 and 8, on the modular collapsible tank trailer 
railing assembly 10a. The like numbered components of modular collapsible 
tank trailer railing assembly 10a are similar to or identical to the like 
numbered components of modular collapsible tank trailer railing assembly 
10. To form the vertical side rails of ladder 50, post assemblies 14x 
replace two adjacent post assemblies 14--14. Post assemblies 14x--14x 
extend downward beneath base members 18--18 to bottom step 52. A rigid 
bottom step 52 is pivotally connected to the lower ends of post assemblies 
14x--14x by bolt assemblies 20. 
Preferably, the upper rail 12a, the middle rail 15, the posts 14a, the base 
member 18, and the other rigid members of the modular collapsible tank 
trailer railing assembly of the invention are made from a rigid metal 
material. A particularly preferred metal is aluminum. 
Although the preferred embodiments of the invention have been described in 
detail above, it should be understood that the invention is in no sense 
limited thereby, and its scope is to be determined by that of the 
following claims: