Wheel loaders started their development much later than other earthmoving machines such as excavators and graders. For decades, cable operated shovels filled the earthworks niche that is today largely the domain of wheel loaders. It wasn’t until the second decade of the twentieth century that the earliest examples of what would develop into wheel loaders appeared. These were cable operated devices mounted on farm tractors, cumbersome to operate and of limited capacity.

However, this equipment heralded the birth of a class of machines whose mobility and efficiency would earn it an important role in all phases of mining, construction and road building. Of course, despite the advantage later development, being able to utilize many existing technologies, the wheel loader has nonetheless undergone an evolutionary process. Some points of interest along the evolutionary path of this reliable and rugged machine are noted below.

• 1920’s saw simple cable operated bucket systems mounted on farm tractors.
• 1929 English firm of E. Boydell & Company builds a .5 cu. yd. cable operated wheel loader using a 28 horsepower Fordson farm tractor.
• 1939 Hough markets a purpose built wheel loader.
• Post WW II – major development breakthrough when Tractomotive Corporation incorporates hydraulic systems in wheel loader design.
• 1952 International Harvester Company purchases the Frank G. Hough Company.
• 1953 First articulating wheel loader the Scoopmobile Model LD 5 built by Portland Oregon firm Mixermobile Manufacturers.
• 1956 Komatsu builds the W120 – their first wheel loader.
• The operator seating position fore or aft of the articulation is a debated design feature amongst manufacturers over many years. The aft seating position is gradually adopted by most major builders.
• 1960’s – decade witnesses rapid growth in wheel loader capacity.
• 1960 Caterpillar Tractor launches the iconic 966 model series – 2.75 cu. yd. with rigid frame.
• 1963 Caterpillar Tractor introduces their first articulated wheel loader the Cat 988 – of 6 cubic yard capacity.
• 1963 Caterpillar Tractor implements articulated steering in the 966 series – the 966B
• 1964 International Harvester Hough Division builds their first articulated wheel loader – the HD 400 of 10 cubic yard capacity
• 1968 Caterpillar Tractor builds Cat 992 with 10 cubic yard capacity.
• 1970 International Harvester Company launches 580 Payloader of 18 cubic yard capacity – world’s largest wheel loader to that date.
• 1979 General Motors builds Terex 72-81 – largest Terex loader 9 cubic yard cap.
• 1988 Komatsu Dresser builds Haulpak 4000 – of 24 cubic yard capacity
• 1990 Caterpillar builds the Cat 994 – 23 cubic yard capacity
• 2000 LeTourneau builds L-2350 of 53 cubic yard capacity
• 2011 LeTourneau L-2350 is still world’s largest wheel loader

References:

• Haddock, Keith, (2002) The Earthmover Encyclopedia, MBI Publishing Company, St. Paul, MN.
• www.letournequ-inc.com

Most machinery exists today as a result of mankind’s desire to minimize labor and boost productivity. An important group of machines that has freed mankind from drudgery and bone- wearying toil are the excavators. Excavators encompass a large group of earth moving machines ranging from the colossal draglines used in strip mining to the miniature hydraulic backhoes employed in construction and landscaping. The most common excavators in much of the 19th and early 20th centuries were cable operated machines. However, with the exception of mining draglines, in today’s world these essential machines of yesterday have virtually disappeared. The cable excavator has been replaced by several machines, most notably the hydraulic excavator. The development of cable excavators was the cumulative efforts of many enterprises over several decades. Some of these firms flourished, becoming international brands, while others faded away or were bought out by the competition. Some of the noteworthy dates and events in the evolution and life of the cable excavation are featured below.

• 18th century development of the steam engine provided a mobile and untiring power source for machines.
• Steam power is applied to an earth moving device in England as early as 1835 – the Otis Steam Shovel.
• Most early shovels were mounted on rails, capable of only 180 degree swing and were mainly used in railroad construction.
• 1880 Bucyrus Foundry and Manufacturing Company was formed in Bucyrus, Ohio and in 1882 builds their first steam shovel – (this machine was incapable of rotating)
• 1884 first fully rotating-shovel built by English company Whittaker and Sons.
• 1904 Bucyrus Company and Marion Power Shovel Company supply steam shovel for building Panama Canal. Bucyrus supplies 77 shovels, Marion supplies 24 shovels.
• 1920’s Companies develop wheeled, tracked; fully rotating cable shovels with diesel and gas power options.
• 1925 Bucyrus Company builds the first dual purpose mine and quarry shovel – 120-B
• 1825 Bucyrus merges with Erie Company the largest US manufacturer of mobile smaller excavators to form the Bucyrus-Erie Company.
• 1940 Bucyrus-Erie goes international by joining with large British excavating equipment manufacturer Ruston & Hornsby Ltd. to form the Ruston-Bucyrus
• Several companies such as Marion, Bucyrus Erie, American, Link Belt thrive and become hallmark cable excavator brands in first half of the 20th century.
• 1950 -1980 hydraulic excavators replace cable excavators except in some large mining and dredging applications.
• 1997 Bucyrus-Erie changes name to Bucyrus International and acquire Marion Power Shovel Company.
• 2000 Bucyrus International Inc. builds the Bucyrus 2570WS dragline – presently world’s largest working dragline excavator.
• 2011 World leader in mining equipment Caterpillar Inc. purchases Bucyrus International Inc.

References:

• Haddock, Keith, (2002) The Earthmover Encyclopedia, MBI Publishing Company, St. Paul, MN.
• http://mining.cat.com

Photo Information:

The Tom Creek Steam Shovel  This historic steam powered cable excavator now rests on the shores of Stuart Lake in Fort St. James within the scenic Stuart Nechako Region of British Columbia.
“The Tom Creek Shovel has been preserved as a tribute to the pioneer families who contributed to the growth and development of the region during the first half of the twentieth century.” 
To learn more about the shovel and this scenic and historic region of British Columbia visit: wwww.fortstjames.ca

Thank you Kevin for allowing us to use the photo.

During the 1800’s as road networks etched their way across the landscape the need grew for more and better maintenance to accommodate the swelling volume of wheeled traffic. The horse drawn vehicles of the day pocked and rutted the soft road surfaces especially during periods of inclement weather. Maintenance equipment of the time was mostly horse drawn, crude and inefficient with devices as simple as timber floats or wagon mounted blades with little or no adjustment.

The ancestor of we know today as the motor grader did not appear until the late 1800′s. In 1885 American businessman J.J. Adams introduced the first horse drawn grader with leaning wheels and fixed angle grading blade. Adams idea of the employing the leaning wheels to compensate for the sideways pull of the angled blade was a fundamental innovation that has been incorporated into grader design till the present time.

The early pull type graders required the combined strength and skill of both horses and operators but they did significantly increase the efficiency and quality of road surface maintenance. Horses eventually were replaced with tractors, powered first with steam, later with gasoline or diesel engines. Equipped with a variety of specialized attachments including rippers, scarifiers and snow plows the modern motor grader is now both large and small a vital machine for mining, construction and road maintenance. Like all modern equipment the motor grader is a product that has evolved through experience and innovation.

A few points of interest along the development route of modern graders are noted below:

• Industrial revolution and population growth spurs road and traffic growth creating need for surface maintenance.
• 1875 – origin of Champion graders when Samuel Pennock’s family company begins manufacturing road construction equipment.
• 1877 – Samuel Pennock  patents a four wheel road scraper named the American Champion
• 1885 — American businessman J.D. Adams, inventor of the leaning wheel concept, introduces the “Little Wonder” – pull type grader with fixed angle mouldboard and leaning wheels.
• 1886 Champion builds their first grader the “Winner” – drawn by teams of two or four horses.
• 1902 Austin Western Road Machinery Company is created through merger of Austin Manufacturing Company and The Western Wheeled Scraper Company.
• 1907 Galion Iron Works Company formed in Galion, Ohio –
• 1911 Galion produces their first grader – pulled by horses.
• 1919  Russell Grader Manufacturing Company builds earliest self propelled grader
• 1920’s power assisted blade controls introduced by various grader manufacturers.  Huber and Galion introduce hydraulic blade controls.
• 1922 Galion builds C Patrol – self propelled grader with rear mounted engine
• 1928 J.D. Adams Company builds their first self propelled motor grader
• 1928 Caterpillar Tractor Company purchases the Russell Grader Manufacturing Company – adding graders to their equipment line up.
• 1928 Champion builds their first self propelled grader “ the Power Maintainer”
• 1931 Caterpillar Tractor builds the “Auto Patrol”
• 1931 Allis-Chalmers enters the grader market
• 1935 J.D. Adams Company builds first mono frame motor grader enhancing blade manoeuvrability and control.
• 1937 Austin Western markets first grader with all wheel steer  and all wheel drive
• 1953 J.D. Adams Company bought by LeTourneau Westinghouse.
• 1962 Letourneau Westinghouse renames product line “ Wabco”
• 1963 Caterpillar Tractor Company introduces the No. 16 grader – largest in their line up of motor graders to that date.
• 1967 John Deere markets their first grader the JD570.
• 1971 Austin Western purchased by Clark Equipment Company -
• 1973 Caterpillar replaces the No. 16 with the 16G featuring articulating body and hydraulic controls
• 1974 Galion Manufacturing Company becomes a division of Dresser Industries Inc.
• 1975 Champion builds the world’s largest production grader to date – the 100T – weighs 202,000 lbs.
• 1980-86  O&K  Orenstein & Koppel builds the O&K G350 weighing in at 90,000+ lbs  – world’s largest production grader during years of manufacture.
• 1981 Clark Equipment Company ceases grader production.
• 1983 Wabco (Letourneau Westinghouse) no longer produces graders.
• 1995 Caterpillar starts the H Series of motor graders.
• 1996 Caterpillar introduces the 24H – their  largest production motor grader on the market to date – (51 feet long, 14 feet high, 130,902 lbs )
• 1997 Volvo purchases Champion Road Machinery Ltd.
• 2004 Champion Motor Graders name reappears with acquisition of Volvo Compact Motor Graders by Champion Industries LLC.  of Charlotte North Carolina.
• 2007 Caterpillar Inc.  takes motor graders to a new level replacing the H series with the M Series featuring “joystick” grader steering and attachment controls.

References

•    Haddock, Keith, (2002) The Earthmover Encyclopedia, MBI Publishing Company, St. Paul, MN.
•    Volvo
•    Caterpillar
•    Champion Motor Graders

The age of steam power allowed the development of traction engines for pulling agricultural implements and wagons.   Steam engine powered traction engines were equipped with wheels whose high ground pressure and limited traction were an impediment in soft ground applications.  Attempts to overcome these challenges resulted in employing ever larger wheels, both in diameter and width requiring increasingly larger machines to propel them.   As the machines grew they reached Titanic proportions and became clumsy and difficult to maneuver.  Replacing the wheels with tracks resolved the issues of high ground pressure and poor traction and resulted in smaller more nimble machines.   The tracks lowered ground pressures gave better traction and with the advent of internal combustion engines allowed for smaller more powerful traction machines.   Many of the early applications for tracked engines or crawlers were for agricultural purposes where soft ground and the need for good traction for pulling agricultural implements are critical issues.    However, the potential of the crawler as an earthmoving machine was soon realized and before long crawlers were being equipped with simple dozing blades, heralding the birth of the bulldozer.   The milestones in the history and development of the crawler tractor are many.

Here are just a few.

• 18^th century  invention of the steam engine
• 19^th century development of wheeled, steam driven traction engines to pull loads and agricultural implements.
• 20^th century – 1904 Holt Manufacturing Company replaces two drive wheels on their steam traction engine with tracks, keeping the front wheel for steering.
• 1906 Holt Manufacturing Company markets their first steam driven crawler.
• 1925 – a hydraulically controlled blade is built by the LaPlant- Choate Manufacturing Company as a dozer attachment.
• 1925 Holt Manufacturing Company and C.L. Best Tractor join forces to create the Caterpillar Tractor Company.
• 1935 Caterpillar builds the RD8 tractor which evolves into the iconic Caterpillar D8 series of tractors.
• 1947 Allis Chalmers builds the HD-19 the largest crawler tractor to that date.
• 1947 International Harvester introduces the TD 24 overtaking the AC HD19 as world’s largest crawler to date.
• 1954 September – GM takes over ownership of the Euclid Corporation and in 1955 markets the world’s largest bulldozer to date the twin engine TC-12.
• 1962 International Harvester builds the TD30 – setting a new record for world’s largest crawler.
• 1963 Allis Chalmers regains record again for building the world’s largest crawler – the HD-41 weighing 70 tons with 524 horsepower engine.
• 1968 General Motors earthmoving division Euclid is renamed; GM dozers are marketed under the new name Terex.
• 1977 Caterpillar introduces the D10 – first Caterpillar model featuring the high drive system.
• 1980 Caterpillar introduces a second tractor featuring the high drive system – the D9L.
• 1982 International Harvester sells construction machinery division which then becomes the International Hough Division of Dresser Industries.
• 1982 Caterpillar replaces conventional drive D8K with high drive D8L.
• 1986  Caterpillar replaces the D10 with the D11N
• 1987 Caterpillar introduces the D8N – the first Caterpillar tractor employing differential steering.
• 1996 Caterpillar introduces the D11R and D11R Carrydozer featuring an innovative blade designed to carry as well as push material.
• 2009 Caterpillar takes bulldozers to a new technological level with introduction of the diesel electric driven D7E model which offers increased production with less maintenance and fuel consumption than previous D7 class bulldozers.

Today bulldozers still occupy an important position in the hierarchy of earthmoving equipment.  Some work, formerly the sole domain of bulldozer, is now being performed by other classes of earthmovers such as hydraulic excavators.  However, with confidence, we can predict this most essential machine will continue to evolve and retain a vital role in the construction, forestry and mining industries.

References:

• Haddock, Keith, (2002) The Earthmover Encyclopedia, MBI Publishing Company, St. Paul, MN.
• Caterpillar

As hydraulic excavators evolved, replacing the cable shovels of yesterday, the diversity and sophistication of available ground-engaging attachments have followed suit. Following is a general discussion of some types of buckets often found on hydraulic excavators in the construction and mining industries today.

The Digging Bucket

Essentially most excavator buckets are intended for digging in a medium which is reflected in specific features of their design. Buckets, whether meant for digging loam, rock or frost, generally adhere to the rule that form follows function. Digging buckets for soft soils have short blunt teeth, while for rock or frost they are pointed and longer to provide better concentration of force and leverage for prying. Bucket width also varies – in hard ground a narrow bucket concentrates ground- penetrating forces along a shorter cutting edge. Another variable is the distance between the stick bucket pin boss and tooth tips. This distance, the tip radius, is generally shorter in buckets intended for hard ground excavation. The shorter distance provides better mechanical leverage for curling and filling the bucket. A well designed digging bucket will employ, depending upon intended use, these and other features to create a durable and efficient tool.

Rock Bucket

The rock bucket is a variation of the digging bucket with design modifications for a special application. Extreme service in prying and ripping rock requires a robust, heavily built structure often equipped with longer sharper teeth mounted on a straight or V- shaped cutting edge. The bucket must have sufficient strength to concentrate power for ripping and prying rock loose while maintaining its structural integrity. Typically these buckets are narrower with a shorter tip radius as compared to a general purpose digging bucket used in softer materials.

V Bucket

The V bucket is a digging bucket whose unique design affords energy savings and productivity gains in some applications.  Instead of the square or rectangular geometry of the face of the conventional dig bucket, the V bucket has a generalized V shaped digging face. The V shape is comprised of three ground engaging surfaces — the bottom and two sides. The bottom cutting edge works on increasing the depth, while the side cutting edges shape the side slopes of the excavation. The cheeks of the bucket taper away from the cutting edges to create a bonnet- like shape to the scoop which reduces side drag as the structure moves through the excavation.
The angled sides of the V bucket allow the operator to efficiently slope the ditch profile as the excavation progresses. The V bucket is commonly used in pipe laying excavation.

Hardpan or Frost Buckets

Hardpan or frost buckets are another specialty digging bucket that employs some of the design concepts of the rock bucket, but with an added feature – the addition of ripper teeth mounted on the back of the bucket. Like the rock bucket, the frost bucket is heavily built with aggressive, sharp teeth mounted on a straight or V shaped cutting edge. The ripper teeth added to the back of the bucket are intended to loosen the compacted soil as the bucket is curled through the dig/load cycle. The material loosened by the ripper teeth can then be pried out and scooped up in a subsequent pass of the bucket.

 Cleanup Bucket

The typical cleanup bucket is essentially the scoop portion of the digging bucket without teeth. Because the cleanup bucket is used in soft or well loosened materials it normally has a larger capacity and is straight edged at the point of ground engagement. The ground engaging edge may be equipped with a bolt on hardened plate steel blade to reduce wear and maintenance. The cleanup bucket is used in a variety of tasks including sloping, leveling, ditching, backfilling and occasionally excavation where the softness of the material allows.

Skeleton Bucket

The skeleton bucket is in reality a specialized digging bucket modified to act like a grizzly mounted on an excavator. The width between the bars will allow only a certain sized aggregate to fall through leaving the larger size in the bucket. The skeleton bucket allows for a versatile and portable method of separating coarser and finer materials.

Conclusion

The foregoing paragraphs provide a brief outline of some common excavator buckets types and uses. Choosing the right bucket is important and can be influenced by many factors including:
•    The machine’s intended role; digging, backfilling, ditching, clearing;
•    The composition and density of the soil type to be excavated, loams, clays, rock;
•    The design of the machine, weight, configuration, power, etc.; and,
•    Bucket width, teeth, guarding, tip radius.

Time spent selecting the right bucket for a job will pay dividends in production, energy savings and machine wear.

References: Caterpillar Performance Handbook. Vol. 39 (2009) Caterpillar Inc. Peoria, Illinois, U.S.A.

Dozer blades are tools and like any tool you need the right one for the job.   Efficient machine applications require the proper dozer attachments for the job at hand.  Dozers are used in a wide variety of construction and maintenance applications for which a number of blade types have been developed.  Soil characteristics, moisture content, compaction, ambient temperatures and terrain are just some of the variables that will influence proper blade selection for optimal dozing productivity.  Using the right blade for the job will mean result in fuel savings, higher productivity, less wear tear on the tractor and a better finished product.    Some dozer blades are designed for a specific application, while others have a broader range of uses and are more often employed.  The following paragraphs provide a brief description of some common dozer blade types, blade mounting arrangements and their applications.

S Blade

The straight blade or “S” is as the name suggests a geometrically straight blade.  The S blade is attached to the tractor by dozer arms that attach at the lower corners of the back of the blade eliminating the option of angling.  The S blade is vertically stabilized with angle braces to the dozer arms that may be outfitted with a hydraulically operated tilt cylinder allowing for horizontal blade adjustment.  Tilting the blade enhances ground penetration by concentrating the cutting force over varying blade lengths.  The tilts also increase versatility to include operations such as ditching and crowning.  Given the straight configuration and lack of side wings to hinder material side spillage the S blade has limited material carrying capabilities.   The experienced operator can improvise and enhance material carrying by building and employing a push trough.

Where the S blade performs best is in medium to harder compacted materials.  The rugged design, weight, and geometry of the blade give it good ground penetrating characteristics which allow for better dozing of harder materials.  The S blade is used in many applications including backfilling, stumping, stripping, shaping and ditching.   The versatility of the blade increases with the skill of the operator in finding means of overcoming design limitations.

The SU Blade

SU stands for semi-U.  This blade is designed to occupy the middle ground between the straight blade and the U blade providing to a lesser degree characteristics of both.  The SU blade is mounted to the tractor with the same heavy straight push arms attached to the lower back of the blade.  The blade is vertically stabilized from the dozer arms with angle braces which will incorporate one or two hydraulic tilt cylinders.    The tilt cylinders provide the ability to alter the horizontal plane of the blade and concentrate ground penetrating forces.   This feature increases the blade versatility to include crowning and ditching.   The distinctive feature that sets this blade apart from the S blade is the addition of the forward curving side wings on either end which work to hamper material spillage.  The gives the SU blade increased materials loading and carrying capability thereby broadening the range of efficient uses for the tractor equipped with this blade.

The SU blade has less ground penetration ability than the S blade, but the more efficient material carrying capability make it a good choice in a number of bulldozer activities including stumping, stripping, backfilling, ditching, crowning and leveling.  The blade works well in soft to medium hard soils, especially with the skillful application of the tilt feature.   The SU blade will have limited efficiency in glacially compacted tills (hardpan) without prior loosening with a ripper.  The SU blade provides a degree of versatility that makes it a common choice for outfitting a tractor.  Combined with an experienced and skilled operator the SU blade will perform well at most tasks.

U Blade

The geometry of this blade is as the name suggests a generalized “U” shape.   The U shape works like a scoop to hold in materials and minimize side spillage off the blade.  This feature gives the U blade good loading and material carrying qualities allowing for more efficient movement of soils over longer distances.   Similar to the S and SU blade the U blade is mounted with heavy dozer arms from trunnions on the sides of the tractor to the lower bottom corners of the blade.   The U blade is vertically stabilized from the push arms with angle braces that incorporate one or two hydraulic tilt cylinders.  The tilt cylinders provide the blade with the ability to concentrate the ground penetrating forces thereby increasing versatility to include operations such a ditching and crowning. The increased width of the U blade lowers the overall ground penetrating forces making the blade most suitable for medium to soft soils.   The limited ground penetrating penetrating characteristic of the blade can be mitigated by mounting a ripper on the tractor to loosen glacially compacted silts such as hardpan or soft rock.

Angle Blade

The angle blade is typically a straight blade pivot mounted on the centre of a “C” frame.  The centre pivot mount allows the blade to be angled to the left or the right to enhance side casting of materials.  On older machines the blades often had manual screw type tilt adjusters on the side arms which vertically stabilize the blade, but on newer machines these were generally upgraded to hydraulically operated tilts either on one or both side arms.  These improvements allowed for greater operator ease of blade horizontal tilt adjustment and consequent productivity increases.

The angle blade works well for a number of uses including, stumping and stripping, shaping, ditching, trail pioneering, and general dozing of medium to softer materials.   The straight geometry of the blade allows material to easily spill off the sides thus reducing its value for carrying materials longer distances.   Experienced operators will partially overcome this deficiency by creating a trough when longer pushes of materials are needed.

Overall the angle dozer allows a broad range of tractor applications that make it a prime choice when outfitting a new machine.

PAT BLADE

PAT stands for power, angle, and tilt.   Though commonly referred to as a type of blade the PAT blade is normally a straight blade combined with multiple hydraulically controlled tractor attachment points allowing for angle, elevation and tilt blade adjustment by the operator.    Enabling quick and easy operator control the PAT blade enhances dozing productivity and tractor versatility.

Summary

Dozer blades and attachment options have evolved to suit changing circumstances ranging from the machines they are mounted on, to the purposes for which they are designed.    Specialized blades have been designed for specific purposes including land clearing, trash handling and brush piling.   As bulldozers increased in power and traction blades have been designed or altered to capitalize on these improvements to increase productivity and reduce energy inputs and wear.   Selecting and equipping a tractor with the proper blade arrangement requires a thorough evaluation of what are the main activities the machine will be engaged in.   This process is not limited to the blade, but also applies to choices of undercarriage, guarding, driveline options and attachments such as rippers.   The time and energy spent in making the right choices whether outfitting a new tractor or deciding on the best used machine to buy will provide owners with optimal performance and good return on investment.