Biosystems and Agricultural Engineering

Growing Oklahoma

Biosystems and Agricultural Engineering

Growing Oklahoma

senior design team small detachable backhoeditch witch logo


Design of a Small Detachable Backhoe

Yen Kean Lee, David W. Crossley, Jacob A. Hamburger



Charles Machine Works, Inc. (CMW) is a manufacturing company that builds construction equipment in Perry, Oklahoma. Over the past 50 years, CMW has become synonymous with building the highest quality underground construction equipment in the world. They began in the late 1940s with a mechanical powered trencher that owner and founder Ed Malzahn built in his father’s machine shop. This one machine has evolved into what the world now knows today as Ditch Witch®. For the past 50 years, Ditch Witch has expanded its lineup to include horizontal boring machines, vibratory plows, and more recently, compact utility machines. Ditch Witch is an industry leader in the trenching market, introducing the first mechanical trencher in 1949, and has continued to be on the forefront with the latest innovative technology ever since. Over the years, their product line has expanded to include various size trenchers as well as vibratory plows and backhoes. In the late 1980s, they began to explore the emerging horizontal boring industry and eventuallyproduced an entire line of directional boring machines. More recently, Ditch Witch has decided to expand its lineup and branch out into the compact utility market. The compact utility market segment has exploded in the last few years and is currently the fastest growing segment of the construction equipment industry. Ditch Witch manufactures multiple models that fall into this category. The vehicles have the capability of attaching over 70 different tools to the front, making these some of the most versatile machines on earth. Currently, this market produces annual net sales of approximately six billion dollars worldwide, making it an excellent venture for any company already involved in the construction industry. Unfortunately, several other companies, both large and small have begun to manufacture similar machines and attachments.



Problem Statement

Our team has accepted the challenge to design a small, detachable backhoe for the SK500 compact utility machine. Currently, Ditch Witch offers a backhoe for this model, but it is outsourced from another company. The purchased backhoe does not satisfy many of the design criteria desired by Ditch Witch. Therefore, Ditch Witch has decided it would be beneficial to their company if they were to design and build a backhoe of their own. This would allow them to offer some additional features as well as help to increase the overall profit margin on the SK500. The backhoe designed by our team will fit the SK500 compact utility machine and adhere to all of the design criteria set forth by Ditch Witch.

Scope of Work

For our design project, the team will be designing a small, detachable backhoe for a compact utility unit manufactured by Charles Machine Works, Inc. in Perry, Oklahoma. Charles Machine Works, also known as Ditch Witch, is one of the leading manufacturers of trenching and underground excavating equipment in the world. Over the past 50 years, the compact utility market segment has grown into a six billion dollar worldwide market. Ditch Witch has released two hugely popular compact utility vehicles: the SK300 and the SK500. These small vehicles can utilize over 70 different attachments, making them possibly two of the most versatile tools to enter the market in the last 30 years. Currently, many of the attachments for the SK’s are purchased from outside vendors. However, Ditch Witch is now interested in producing more of these attachments “in house.” This offers multiple benefits including the knowledge that the equipment they sell is completely compatible with their machines and an increased profit margin. One such attachment is the mini backhoe. After meeting with the design engineers from Ditch Witch, the team set forth some of the criteria this unit was expected to meet. First of all, it would have to attach to the SK500 unit via the quick-attach plate in the front of the machine. Our team would also have to assure the overall width of the backhoe did not exceed 36 inches, making even the smallest spaces accessible. In addition, the backhoe would also have to dig to a depth of at least 78 inches and have an overall weight not exceeding that of the current purchased unit (780 lbs.). The backhoe must incorporate some sort of mechanism to “lockout” the use of the tilt function on the attachment plate. Users will often rotate the attachment plate to reposition the backhoe to get a deeper or larger hole.



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