Lewis R. Heim

Lewis Rasmus Heim (19 September 1874 – 29 March 1964 ) was an American machinist and businessman who was the inventor of the Centerless Cylindrical Grinder, the Heim Joint Rod End Bearing and a pioneer of modern spherical, ball and roller bearings.

Heim was a self-taught machinist with an ability to visualize complex mechanisms and mechanical processes that resulted in the creation of novel machines, machine tools, manufacturing methods and mechanical bearings and was granted 92 patents over his lifetime. His inventions ranged from machines to manufacture hats and automate the ironing of fold collars to precision grinders and industrial bearings used in automobiles, aircraft and machinery.

Inventions

Heim was an inventor of many types of machines, mechanical devices and manufacturing processes. In 1895, at the age of 21, Heim developed a hat-stiffening machine (Patent No. 573,876) that freed the operator from having to hold or manipulate the hat during the process of applying stiffening compound. Heim's invention saved time, improved quality and lowered the cost of stiffening hats. Heim subsequently developed six additional complementary hat-making machines that were bought by many local manufacturers. In 1901, a large multinational manufacturer of hat-making machinery purchased six of Heim's patents.

In late 1913, Heim conceived of a two-wheel grinding machine that used a slowly rotating regulating wheel for controlling roll rotation against a high-speed grinding wheel. Heim filed his first patent (1,210,937) for a two-wheel centerless cylindrical grinder using a regulating wheel in March 1915. Heim called his invention a double-ring wheel roll grinding machine that ground uniform cylindrical work (rolls) using the radial sides of the two wheels. In order to grind a succession of rolls and to induce automatic forward motion of the rolls through the grinding zone, Heim installed an inclined centerless carrier in between the two wheels. The machine was able to grind 100 rolls for every roll ground on center-type grinders, grind to precision dimensions and greatly reduce production costs.

Following the double ring-wheel machine, Heim developed centerless grinders using the peripheral surfaces of the two wheels that became the standard configuration for all future centerless grinders. His machines used either inclined carriers (1,264,930) or forward tilted regulating wheels (1,579,933) to draw the work through the grinding zone. The machines were able to grind both uniform and non-uniform cylindrical work with later machines able to achieve extreme precision to within 0.00001 inch (0.25 microns) and perfectly round work. Heim also developed tools and methods for grinding cylindrical work with various profiles including tapered, headed, rings, concave and convex shapes and was granted a total of 28 patents for centerless grinding. Heim's bearing consisted of a ball with a drilled-through hole, a threaded shaft (rod) that contained a circular head forming the outer race, and two soft-metal bushings that sealed the ball into the head. The threaded shaft allowed the rod end of the bearing to be connected to a moving component and adjusted as necessary for a tight connection. On September 29, 1942, Heim filed his first patent application for the four-piece rod end bearing that was granted patent number 2,366,668 on January 2, 1945.

Similar methods were also used to manufacture ball and roller bearings with unbroken races that eliminated the need for slots or notches used to insert the rolling elements. Slots and notches created breaks in the smooth race surfaces that accelerated wear that reduced the life of the bearing. Heim developed machines and methods, such as those in patents 2,910,765 & 2,913,810, for expanding or contracting metal components that allowed for the manufacture of bearings with perfectly smooth races. These bearings contained a full complement of balls or rollers that made the bearing suitable for higher load ratings as well as extending its operating life. Many of Heim's machines and methods developed in the 1950s and 1960s continue to be employed in the manufacture of modern rolling bearings.