This invention relates generally to a pedestrian railing used as a barrier or guard to protect pedestrians and bicyclists, and specifically, to an aluminum picket railing and the method of construction that reduces production costs significantly, while increasing structural strength. 
Guard railings are used near public conveyances such as walkways and bicycle paths to protect pedestrian traffic and cyclists for safety purposes.  Although there are many variations in the construction of barriers, one type of guard railing uses a plurality of vertical, spaced apart aluminum pickets that are welded at top and bottom to horizontal or inclined bars.  Metal posts are connected at spaced intervals that anchor the guard railing to the ground. 
The disadvantages of welding numerous vertical aluminum pickets (at both ends) to top and bottom horizontal or inclined bars are loss of material strength and its expense.  Although welding certainly provides very rigid construction and prevents removal or separation of the pickets from the railing itself, welding does weaken aluminum within one inch of the weld joint and is very costly and time consuming at the time of construction.  The choice of aluminum is because of its ability to withstand harsh outdoor environments without rusting or severe oxidation.  Aluminum is a difficult metal to weld. 
The prior art shows a variety of different types of railing constructions.  U.S. Pat.  No.  4,346,872, issued Aug. 31,1982 shows a balustrade construction that employs screw fasteners in construction.  U.S. Pat.  No.  2,590.929 issued Apr. 1, 1952 shows a railing that is pre-fabricated.  U.S. Pat.  No.  5,649,688 issued Jul. 22,1997 shows railings with continuous spacers.  U.S. Pat.  No.  5,200,240 issued Apr. 6, 1993 shows an aluminum railing apparatus that uses screw fasteners.  U.S. Pat.  No.  4,586,697, issued May 6, 1986 shows another balustrade construction from extruded aluminum.  U.S. Pat.  No.  6,029,954 issued Feb. 29, 2000 shows a railing assembly that utilizes screw fasteners for construction.  U.S. Pat.  No.  6,041,486 issued Mar. 28, 2000 shows a method of assembling a fence. 
When used by government for pedestrian walkways or bicycle paths, the barrier or guard railing should be rigidly constructed for use not only in protecting pedestrian traffic on walkways or cyclists on pathways but also to prevent theft or damage by people trying to deliberately damage public property.  Thus it is important that the railing be of a rigid, permanent type construction that cannot be readily disassembled, while at the same time being of reduced cost and complexity.  This is especially true in the public arena where there is a requirement for large numbers of pedestrian and bicycle railings. 
The present invention provides an improved pedestrian railing and method of construction that includes a rigid structure and method of manufacture that greatly reduces construction costs without reducing strength or rigidity of the entire structure. 
A pedestrian railing and the method of construction comprising top and bottom parallel horizontal or inclined bars that each include a recessed, specially configured channel, disposed continuously along a predetermined segment of the railing bar exterior surface facing or projecting outwardly substantially radially.  Each of the railing bars (top and bottom) has the same specially configured channel, viewed in cross-section. 
Each pedestrian railing top and bottom bar external channel that protrudes from a peripheral section is substantially u-shaped in cross section.  The channel walls parallel sides have coplanar, perpendicular, inwardly directed tabs, mid-length, separated at their ends by a space.  The coplanar tabs divide the bar channel into two separate passageways.  The railing bar channel is sized in width to receive (snugly) the end portion of a rectangular picket that fits into the recessed railing bar channel portions between the channel side walls.  When the picket is in place, each picket end engages each bar channel and, abuts vertically the channel tabs that are used for holding each vertical picket in position in the vertical direction between top and bottom railing bars.  The end face of each rectangular picket may be formed or cut at a ninety degree angle to the longitudinal axis of the picket for railings that are substantially positioned horizontally on flat ground but may be cut at an angle when used with top and bottom bars in a railing that is disposed inclined on a hill wherein the pickets are at relatively acute angles between the top and bottom rails.  The end face of each picket in the inclined case can be cut at the appropriate angle, so that the angle between the top and bottom rail and the picket is equal to the end face angle cut on each of the picket ends to make each picket fit snugly within the channel. 
A plurality of picket separating spacer plugs are used in the pedestrian railing construction to rigidly separate (at top and bottom) each vertical picket from an adjacent picket, and to hold the vertical pickets firmly in place.  The spacer plugs are elongated, rigid, metal bars that are shaped in cross section to interlock and fit (slidably) within each top and bottom railing bar channel. 
A spacer plug has a cross-sectional shape and area (somewhat like an I-beam cross section) that is used to hold each bar picket in position laterally and is employed between each picket within the bar channel.  Because of the spacer plug""s unique cross-sectional shape, the spacer plug fits snugly and slides longitudinally along the top and bottom railing bar channels during the manufacture of the entire railing assembly when the pickets and spacer plugs are inserted.  Once in place, each adjacent picket is separated rigidly by a separate spacer plug that is mounted in the top railing bar channel and the bottom railing bar channel.  The spacer plug has end faces that are at a ninety degree angle to the longitudinal axis of the spacer plug when used in railings wherein the railing is mounted on flat ground representing the horizontal earth plane.  In the situation where the entire railing is inclined at an angle relative to the earth""s horizontal plane, such as a hill, the end face of each spacer plug may be angularly cut (not perpendicular) relative to the longitudinal axis of each spacer plug to accommodate the inclined angle so that the end face of each spacer plug fits snugly against the picket end portion in the bar channel that is used for the inclined environment.  The cross-sectional shape of the space plug can be made to save the amount of metal used. 
The ends of the pedestrian railing assembly are rigidly held together by vertical end bars that are welded to both the top and the bottom horizontal railing bars, once the pickets and spacer plugs are in place, adding tremendous rigidity to the entire rectangular structure.  The last picket at each end of the entire guard railing structure is welded in place, top and bottom, to lock in the other pickets and spacer plugs. 
A plurality of vertical support posts, which are preferably aluminum, are permanently attached to the ground in concrete pads and the top railing bar and the bottom railing bar.  The posts are vertically disposed and placed apart as necessary and support the entire railing structure above the ground.  The pickets can be arranged in a plumb line on an incline as are the support posts under certain hill conditions if required. 
By using slidable, rigid spacer plugs along with a plurality of pickets that all fit within top and bottom railing bar channels that project radially away from the periphery of the top bar and the bottom bar, the entire picket and railing bar assembly can be assembled and manufactured without welding each of the pickets individually to the top and bottom railing bars, except for the end pickets. 
It is an object of this invention to provide an improved, aluminum pedestrian safety railing of increased strength and at reduced construction costs. 
It is another object of this invention to provide an improved safety guard railing for use as a safety barrier along public walkways to protect pedestrian traffic and bicycle paths to protect cyclists that is non-complex to assemble, yet rigid in construction. 
These and other important objects, advantages, and features of the invention will become clear as this description proceeds. 
It is to be understood that both the foregoing general description and the following detailed description are explanatory and are not restrictive of the invention as claimed.  The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate embodiments of the present invention and together with the general description, serve to explain principles of the present invention.