Keeping Roads is Part of Ame )en in Winter Defence Plans
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irECHANIZED equipment has almost wholly superseded Mall other means for cleaning 'city and village streets and keeping highways free of snow and ice in North America. Increased burdens have been imposed on the maintenance divisions of city street departments and state, county and provincial highway commissions by the tremendous growth in the use of lorries, • buses and cars during the past three decades.
More frequent sweeping of a community's total street mileage is necessary to avert the cutting and puncturing of pneumatic tyres by broken glass, nails and metal fragments, and snow must be removed speedily from the traffic lanes. Snowfalls that sometimes blocked roads for days could be tolerated in the era of horse-drawn traffic, for when ieL cice (.1 it made travel by sled and cutter easier and quicker, but now it delays motor traffic and endangers it by destroying the chances of obtaining traction.
Whilst motor vehicles have thus made more highways work necessary, they have more than paid for it by way of vehicle and driver licence fees and taxes on petrol. Moreover, they have provided the means and shown the way for doing the work faster and cheaper, for all the mechanized equipment used is employed in conjunction with lorries, or is a specialized development utilizing a mobile internal-combustion power plant.
Most of the street mileage in cities and large villages is now swept daily, or at least once a week, with power
driven machines, The work is clone as gulch as possible by night, to avoid interference with normal traffic. The mechanical sweepers are highly specialized machines, which
a 5f-ft. or 9-ft, wide path adjacent to only the
When, in the course of about an hour, the dirt bin or hopper has become filled with refuse, the driver pulls a lever and the load is dumped at the kerbside near a street intersection, and before morning, perhaps even within an hour, a driver shovels up the dumped load into a lorry and hauls it away. Sweeping is done at a rate of about 5 to 8 m.p.h., varying with conditions, and at about only one-tenth of the cost of hand sweeping.
Efficient Street sweeper Design
Thep latest models of power sweepers are petrol-propelled three-wheeled units. One of two principal makes—the Patrol, manufactured by, the Austin-Western Road Machinery Co.-50 of which were purchased in one order by the Department of Sanitation of the City of New
York, is powered with a 30 h.p. slow-speed, heavy-duty engine mounted above the single wheel at the front. The machine has an overall length of 15 ft. on a 7*-ft. wheelbase, sweeps a 5k-ft. path and can be turned in a 10-ft. radius. flung transversely behind the rear driving wheels is a cylindrical broom, which is 36 ins, in diameter and 4 ft. long. This sweeps litter forward directly into a covered bin in front of the rear axle and beneath the operator's seat. The bin, made of welded, rust-resistant steel, holds 2-4 cubic yds. and is rear tipped to a high angle by hydraulic power.
To either right or left of the front wheel, as ordered, a gutter broom of truncated-cone shape is mounted to rotate horizontally and brush refuse towards the main broom.
Available As most street sweeping is done in seasons of mild weather, no provision is made on the standard model for protecting the operator against inclement conditions, but a sheet-steel cab is available for mounting on the sweeper, as shown in an illustration. The shipping weight, without cab, is approximately 6,500 lb.
The other principal make of sweeper-,the Elgin, manufactured by the Elgin Corporation—is a larger machine having an overall length of nearly 15 ft. and a width of 8 ft. 9 ins. It is powered with an 83 b.h.p. six-cylinderecl engine, sweeps a 9-ft. path and turns in a 14-ft. radius, It operates in a reverse direction from the other machine, the engine being mounted at the rear and the pair of driving wheels at the front, and it has a ,sweeping speed up to 8 m.p.h. The main cylindrical broom, directly under the operator's seat, sweeps on to a belt conveyor that carries the refuse up and forward into a 2*-cubic yd. closed dirt box, which dumps to the front.
There are twin side brooms 30 ins. in diameter for cleaning gutters and brushing dirf under the machine, each having two speeds of rotation and being flexibly mounted to conform with pavement contours and to avert damage from contact with kerbs or other obstructions. This sweeper tips the scales at 11,350 lb.
Two Elgin machines owned by a suburban residential city with a 70,000 population in the New York City metropolitan area do all the work on 60 miles of smooth-paved streets, most of them lined on both sides by trees, the leaves from which increase the volume of litter by one-half in the autumn months. Operating costs are calculated on lineal miles of kerb rather than on yardage of surface swept, as the rapid flow of motor vehicles keeps the middle of the streets clean of litter and dust. Operation of the sweepers costs 444 cents (about 2s, 3d.) per kerb mile and a total of 70 cents (3s. 5d j including interest on investment, maintenance and depreciation.
Equipment Used for Snow and Ice Clearance The removal of snow and ice gives highways maintenance men in northern states of the Union and along the border in Canadian provinces their severest tasks. A season's snowfall near the international border on either side normally amounts to a depth of 18 ft. In the United .States, 300 to 500 miles south of the border, it may :total only 2 ft. or less, but quick temperature fluctuations above and below the freezing point make icing conditions bad, and alternate thawing and freezing produce heaving and cracking of road paving.
Owing to climatic differences in the two east-west belts and to the fact that much more horse-drawn traffic still obtains in Canada, the equipment used and practices followed in dealing with winter conditions vary considerably. Also, city and village street departments have a different problem from state, county and provincial highway commissions. Therefore, there is much variety in the class of equipment employed for snow and ice work. Nearly all types of equipment are designed, however, to be attached to, or mounted on and propelled by, motor lorries, tractors or power road graders, which usually are owned by city street departments and highway commissions. The equipment most 'universally and frequently used on both urban and rural highways is the blade plough, which ia designed for pushing light and moderately deep snowfalls to the sides of the road, It is simply a rectangular steel plate curved concavely to the front and pivoted to iron bars or a frame by which it is attached to the front end of the lorry frame in such a way that it can be raised by a chain or a hydraulic piston into an inoperative position for travelling. The plough is adjustable to several horizontal angles to the lorry axis from 20 to 45 degrees and is reversible for moving snow to either side.
An automatic blade trip allows the mouldboard to tip backward at the bottom when a surface obstruction is hit, thereby preventing damage. A swivel device at the middle enables the mouldboard to tilt endwise, as much as 20 ins. to 30 ins., to conform with the contour of highly crowned roads or to ride up a kerb or hard-packed snow.
Somewhat similar to the foregoing are one-way conical speed ploughs, which are built for use with lorries having capacities from 14 tons up to 8 or 10 tons. These are irreversible, but are adjustable to different angles, and the mouldboard is curved to approximate the shape of a section of a truncated cone. The mouldboards increase in height from .front to rear end.
This shape of plough was scientifically designed to take advantage of the power and speed of modern lorries to roll the snow higher in the mouldboard and throw it farther from the rear end to the roadside. The faster the £26 vehicle is driven, the more effective this action becomes because of the momentum imparted to the snow.
Also, for out-of-town use is the railroad-type V plough, which has the general shape of two one-way conical ploughs joined at their front ends. Although it has rather general utility and is made in sizes for use with lorries of all capacities from 14 tons up to 10 tons, its primary purpose is for breaking through deep snow and heavy drifts to open traffic lanes as quickly as possible. It cuts into the drifts and pashas the snow to both sides at the same time. Sizes are as follow: cutting width, 7 ft. to 9 ft.; overall width, .9 ft. to 12 ft.; height at front, 2 ft. to 4 ft. 8 ins.; and at rear, 4 ft. to 74 ft.
Wings and Rotary Ploughs and Their Uses The push ploughs described serve merely to displace snow from the middle of the pavement to the shoulders or gutters, where it is formed into windrows. If left on the shoulders close to the pavement, the snowbanks constitute a traffic hazard and when the snow thaws the water flows back upon the road surface, where it freezes at night and is a cause of skidding. It also seeps underneath the pavement and, subsequently freezing, lifts the hard sur Lacing, breaking joints in concrete and producing cracks in any kind of paving, thus increasing the cost of maintenance.
For these reasons, snowbanks should be cut down and moved back off the shoulders and beyond side drainage ditches. Wings for this purpose are used in conjunction with one-way and V ploughs, or by themselves. They closely resemble blade ploughs, but are mounted on a frame usually attached to the side of a lorry and held by jointed steel struts which take the thrust. They can be lowered to ground level or raised as high as the top of the driver's cab by a steel cable operated by hydraulic power, and can be adjusted to any desired vertical angle. Sometimes a pair is used with a V plough to clear a path from 15 ft. to nearly 17 ft. wide in a single trip.
Both ploughing and removal of snow are combined functions of another type—the rotary plough. This class of machine is employed, mainly in areas near the Canadian border and in mountainous regions, for opening traffic lanes quickly through drifts that often are 5 ft. to 15 ft. in depth, and sometimes rather firmlY packed by strong wind.
One make—the Sno-Flyr, built by Wm, Bros. Boiler and Manufacturing Co.—operates in a similar manner to the rotary ploughs used on locomotives in western mountain passes. A power-driven shaft rotates a pair of discs fitted with cutting and throwing blades. These rotors operate within the openings of a W-shaped metal shield, which a lorry or tractor pushes into the snowdrift, and they drive the snow upwards and outwards through a pair of chutes, to a distance up to 200 ft. from the middle of the highway.
The operation is spectacular and impressive. Made in several models and sizes, some have the rotors driven by the lorry engine if of 95 b.h.p. or more, others by a 95 b.h.p, engine mounted on the plough between the chutes, and tha. larger models by an auxiliary engine mounted on a lorry body.
Another make—the Snogo, manufactured by the Klauer Manufacturing Co.—has a series of spiral cutting and feeding blades on two or three parallel, horizontal shafts mounted in the front of a rectangular shield. The screws cut into the snow and force it to a rotor that drives it through a top chute and sideways up to 200 ft. All of the several models, built in sizes for use with lorries ranging from 3-4 to 5 tons capacity and with a track-laying tractor, derive power for operating the cutting and throwing mechanism from an auxiliary power plant of 80, 110 or 170 b.h.p„ which is .fnounted at the back of the cob on the lorry chassis or on the tractor frame.
Equipment Employed for Loading Snow into Lorries Large snowbanks left kdjacent to kerbs in business thoroughfares interfere with the parking of delivery vehicles and the same objection applies to piles of snow in solidly built-up residential streets. Moreover, the piles considerably reduce the width of clear traffic lanes. Thus. in large cities the snow is removed so soon as possible after it has been-ploughed from the middle of the streets. This is accomplished by one or other of two methods.
Some communities utilize for the purpose rotary ploughs of the types described, to which hydraulically raised adjust ab:e loading chutes are attached. These machines can break up the snow piles, even when somewhat frozen, z.nd load the snow to a height of 9 ft. or Apra in lorries driven alongside them as they move. The loading rate varies with the quantity and condition of the snow and with Vie size and power of the plough, but it is not unusual to load two 5 cubic yd. bodies per min.
Other cities employ conveyor-type snow loaders mounted on wheels or crawler treads. These have an open belttrough, extending at about a 45-deg angle from the street surface at the front of the machine to the discharge end high above the rear. Power-driven cutters in front break up compacted snow and push it on to a moving belt having cross cleats that carry it to the top of the trough, whence it is discharged into lorries driven alongside as the machine slowly moves forward. The city of Westmount in Quebec province, a residential community, has owned and operated loaders of the wheeled type—the Fox, manufactured by the Sawyer-Massey Co., of Hamilton, Ontario—since 1932.
Compacted Snow and Ice Treated with Abrasives and Chemicals
In Canada, snow is not removed completely from city streets and provincial highways, some 2 ins, or more of compacted snow being left to provide nearly frictionless gliding by the steel runners of horse-drawn sleds and cutters. But, in most states south of the border, bard. packed snow as well as ice is considered detrimental and even hazardous to motor traffic. Common practice, therefore, is to sprinkle sand or cinders over such surfaces, especially on gradients, to act as an abrasive so as to give good traction.
Calcium chloride is mixed with the abrasive in many areas. The particles of chemical thaw the snow or ice, perforating it with a multitude of vertical holes and forming a solution that has a lower freezing point than water, so
• that it softens and loosens the frozen material from the pavement. Then the wheels of passing vehicles soon break it up and the fragments either melt away or are scraped from the surface by a road machine. In some places rock r:t. is used for the, same purpose, alone or mixed with sand or cinders. Whatever the material, it is applied with a sand spreader.
Highway authorities in North America now regard the keeping of roads open to, traffic throughout the winter, without a day's interruption, of national importance to the gigantic programme of aid to Britain and preparedness for
American continental defence. W.H.P.