THE SCREW JACK STORY |
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Our company is proud to be associated with manufacturing and development of screw jack products with our partners Duff-Norton over the past 60+ years. You may be interested to how the product has evolved through the centuries. The virtues of using a screw as a machine, essentially an inclined plane wound round a cylinder, was first demonstrated Archimedes in 200BC with his screw used for pumping water. There is evidence of the use of screws in the Ancient Roman world but it was the great Leonardo da Vinci in the late 1400’s who first demonstrated the use of a screw jack for lifting loads. Looking at Leonardo’s design from so long ago, it is incredible to see the use of a threaded worm gear, supported on bearings, that rotates the turning of a worm shaft to drive a lifting screw to move the load - instantly recognisable as the principle we use today! We’re not sure what application Leonardo’s invention was intended for but it seems to have been relegated to the history books along with the helicopter and tank for almost four centuries. It is not until the late 1800’s that we have evidence of the product being developing further. With the industrial revolution of the late 18th and 19th centuries came the first use of screws in machine tools from English inventors such as John Wilkinson and Henry Maudsley The most notable inventor in mechanical engineering from the early 1800’s was undoubtedly the mechanical genius Joseph Whitworth. He may have had the face of a baboon, but Whitworth recognised the need for precision had become as important in industry as the provision of power. While he would eventually have over 50 British patents with titles ranging from knitting machines to rifles, it was Whitworth’s work on screw cutting machines, accurate measuring instruments and standards covering the angle and pitch of screw threads that would most influence our industry today. Whitworth’s tools had become internationally famous for their precision and quality and dominated the market from the 1850’s. Inspired young engineers began to put Whitworth’s machine tools to new uses. During the early 1880’s in Coaticook, a small town near Quebec, a 24-year old inventor named Frank Henry Sleeper designed a lifting jack. Like da Vinci’s jack, it was a technological innovation because it was based on the principle of the ball bearing for supporting a load and transferred rotary motion, through gearing and a screw, into linear motion for moving the load. The device was efficient, reliable and easy to operate. It was used in the construction of bridges, but mostly the railroad industry, where it was able to lift locomotives and railway cars. Local Coaticook industrialist, Arthur Osmore Norton, spotted the potential for Sleeper’s design and in 1886 hired the young man and purchased the patent. The “Norton” jack was born. Over the coming years the famous “Norton” jacks were manufactured at plants in Boston, Coaticook and Moline Illinois. Meanwhile, in Alleghany County near Pittsburgh in 1883 an enterprising Mississippi river boat captain named Josiah Barrett had an idea for a ratchet jack that would pull barges together to form a "tow". The idea was based on the familiar lever and fulcrum principle and he needed someone to manufacture it. That person was Samuel Duff, a proprietor of a local machine shop. Together, they created the Duff Manufacturing Company, which 1890 had developed new applications for the original "Barrett Jack" and extended the product line to seven models in varying capacities. Over the next 30 years the Duff Manufacturing Company became the largest manufacturers of lifting jacks in the world, developing many new types of jack for various applications including their own version of the ball bearing screw jack. It was only natural that in 1928, The Duff Manufacturing Company Inc. merged with A.O Norton to create the Duff-Norton Manufacturing Company. Both companies had offered manually operated “screw jacks” but the first new product manufactured under the joint venture was the Air Motor operated Power Jack that appeared in 1929. With the aid of the relatively new portable compressor technology, users now could move and position loads without manual effort. The jack, used predominantly in the railway industry incorporated an air motor manufactured The Chicago Pneumatic Tool Company. There was clearly potential for using this technology for other applications and only 10 years later in 1940, the first worm gear screw jack, that is instantly recognisable today, was offered Duff-Norton, for adjusting the heights of truck loading platforms and mill tables. With the ability to be used individually or linked mechanically and driven either air or electric motors or even manually, the first model had a lifting capacity of 10 tons with raises of 2” or 4” Over the past 60+ years, the product has evolved to push, pull, lift, lower and position loads of anything from a few kilos to hundreds of tonnes. Most features now offered our competitors were actually designed and patented Screw Jack & Duff-Norton over the years. A screw jack that has a built in motor is now referred to as a linear actuator but is essentially still a screw jack. These days, screw jacks can be linked mechanically or electronically and with the advances in motion-control, loads can be positioned to within microns. Improvements in gear technology together with the addition of precision ball screws and roller screws mean the applications for screw jacks today are endless and a real alternative to hydraulics in terms of duty cycles and speed at a time when industry demands cleaner, quieter and more reliable solutions. If you are wondering how wide ranging the uses of screw jacks are then you may be surprised. Although normally hidden away, they are the integral part of many machines that impact our daily lives. Long live the screw jack! |
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