FOR S E R P ENT INE DR I V E S Y S T EMS Since 1923 Ramsey Products Corporation Duplex Silent Chains

Ramsey Duplex Silent Chains For Serpentine Drive Systems Ramsey Products specializes in the design, manufacture, and application of silent chain drives, also known as inverted tooth or toothed chain drives. For more than 80 years this has been our focus, and today we remain committed to providing our customers with the world's widest range of top quality silent chain products. Because we specialize in silent chain, we understand how important it is to choose the right chain and sprockets for each application. Whether selecting components for a new application, replacing an existing chain, or...

3 Silent Chain Fundamentals A Ramsey silent chain operating at high speed. Note the smoothness and lack of vibration Another advantage of two pin joints is that they wear uniformly over the life of the chain. Unlike roller chain and other single pin chains, this provides for consistent linear velocity throughout the length of a chain. Roller chain and most other chains with straight sidelinks do not elongate uniformly. The pitch of links containing rollers stays essentially constant, while wear of bushings and pins causes every other pitch of the chain to elongate by P. This creates velocity...

Chain Identification 4 1. Style - Chain style can be identified by the shape of the driving links. Rampower Duplex SC Duplex Ramflex 2. Pitch - Chain pitch, the distance between pin contact points, is easily estimated by measuring the distance between the centers of three consecutive pin heads and dividing by 2. Pitch is typically expressed in inches. 3. Width Over Heads - Chain width over heads is simply the distance across the chain’s “riveted”or “headed”pins. 4. Assembly - (For SC and Rampower duplex only) Chain assembly is identified by counting the number of adjacent, similarly arranged...

SC and Rampower Duplex -- Ramflex Ramsey manufactures a full line of sprockets for SC duplex, Rampower duplex, and Ramflex chains. All sprockets can be fully machined to your specifications or you can request they be supplied with an unfinished bore to allow secondary machining. Ramsey also supplies sprockets to replace most competitor’s products. We welcome all inquiries. Materials Sprockets are typically made from carbon steel or ductile iron, with sprocket teeth heat treated to a minimum Rockwell hardness of Rc 50. Class 30 gray iron is also available , but with unhardened teeth. Other materials...

Sprockets. Sprockets must have a minimum of 21 teeth to assure proper chain wrap. For smoother, quieter drives, use a larger number of teeth. Drive Ratios. Ratios of 12:1 or greater are possible, but above 8:1 it is usually desirable to make the reduction in two steps. Chain Tensioning. For best results it is important to maintain proper chain tension. A correctly tensioned chain will not sag excessively when stationary and will not whip or surge when running. It is also important not to over tension as this could lead to pre-mature chain failure. Use as little tension as is necessary to produce...

11 Drive Selection Example DRIVE SELECTION EXAMPLE Plastic extruder Power source: electric motor Power: 15 hp Shaft speeds: 1750 RPM (N1), 1600 RPM (N2), 400 RPM(N3), 400 RPM(N4) Shaft diameter (N1)= 1.000 inches 1. A preliminary drive layout in illustrated below. Our initial drive selection will assume that 1/2” Pitch Rampower is used. 2. The driving shaft #1 is also the fastest shaft in this example. We select an initial sprocket size of 21 teeth. From the sprocket table on page 9, the maximum bore for the 21 tooth sprocket is 1.875” , so this sprocket will accomodate the 1.000” shaft diameter....

Installation and Lubrication Proper drive lubrication is essential for a long service life. In sufficient quantities the lubricant penetrates chain joints to protect against corrosion, dissipate heat, cushion impact, and flush away debris. For most applications a good grade of non-detergent petroleum based oil is recommended. Multiviscosity oils are not recommended. Generally greases and high viscosity oils are too thick to penetrate chain joints and should be avoided. Lubricant may be applied by drip, bath, of forced feed, depending on the chain speed. Forced feed lubrication is optimum and...

13 Chain Connection CHAIN CONNECTION Once the links in each end are properly laced together, chain connection is completed by first inserting the longer pin and then the shorter pin. Position the pins so that the convex surfaces contact one another. Complete the connection by putting a washer, or side link, on the long pin and then fasten with a spirol pin or cotter. Optional annealed connecting pins are available that are secured by peening over the pin end. With SC and Rampower duplex it is important to properly locate spacer bushings during connection. For 1/2” Pitch Rampower and All Pitches...

14 Service Factors Service factors are used during drive selection to compensate for less than optimum drive conditions. The chain width formulas on page 10 are based on the following drive conditions: * Power source = electric motor, hydraulic motor, turbine, or engine with fluid coupling * Proper lubrication For conditions that differ from those listed above, the power to be transmitted must be multiplied by a service factor to obtain the design power. The design power is then used to calculate the required chain width. Select an appropriate service factor from the service factor table, then...

Inspection Periodic drive inspection and adjustment will often result in increased service life and lower costs. An inspection should include sprocket alignment, tension, lubrication, and the general condition of chain and sprockets. Tensioning and Elongation As a chain wears, its pitch will elongate and the chain will wrap an increasingly larger pitch circle. Re-tensioning of the chain will normally eliminate problems associated with excess chain slack Also, with Ramsey chains this elongation occurs uniformly throughout the length of the chain so efficient, smooth operation is maintained. However,...