HV Inverted Tooth Chain


Catalog excerpts

HV Inverted Tooth Chain - 1

‘HV’ Inverted Tooth Chain Drives For High Velocity, High Horsepower and High Efficiency Drives with smooth transmission of load in a compact space. Morse HV Drives provide the Drive Designer with a new concept in the transmission of power for high speed, high load applications. Proven in a wide range of applications from high production automobiles to custom-designed flood control pumps, HV Drives offer opportunity for flexibility, compactness, weight saving and economy. In the late 1940’s Morse Chain Engineers developed the original design of ‘HV’ to meet the high speed, high load requirements of Oil Well Drilling equipment. The first chain 2” Pitch x 12” Wide transmitted 1300kW at 650 r.p.m. on the slush pump of a drill rig. Success on this and similar applications led to the further development of a family of chains from 3/8”to 2” pitch which have been successfully applied to a wider variety of industrial applications including Roll Grinders, Dynamometers, Pump Drives, Gas Turbine Starters, four Square Test Rig, and many Automotive Transmissions. Further development of HV chain enables drives over 2,500kW being accommodated with standard chain widths. ‘HV’ Chain Design The Chain assembly consists of inverted tooth link plates, laced alternately and connected by two steel pins of the same cross sectional geometry, which form an articulating joint between the link sections. ‘HV’ Link Plate Design The link design in the original HV pitches - 3/4”, 1”, 11/2” and 2” (Fig 1) had been tested and proven for many years. The link crotch is located slightly above the line of pull and all corners are rounded to minimise the possibility of stress risers and to ensure maximum performance on high load industrial applications. The 3/8” and 1/2” pitch chains (Fig. 2) have a new link contour for increased speed requirements, with the link crotch below the line of pull, and this design is now extended to include 3/4” and 1” pitches. Photo-elastic studies of various link shapes and aperture positions produced the design with the lowest level of stress concentration. Improved metallurgy, and development in design and pressure angle, achieve maximum load capacity with high speed performance. Carefully controlled shot-peening of the links gives them a uniform, matt grey finish and results in an improved level of link fatigue resistance. Concentric Pin and Rocker Joint The joint consists of a pin and rocker of identical cross section and contact radii. When chain engages the sprocket teeth the curved surfaces roll on each other eliminating sliding friction, and joint galling. The radii of the pins is selected to give almost perfect pitch compensation to minimise chordal* action. Before engagement with the sprocket the contact point of pin and rocker is below pitch line (Fig. 3). When chain engages with the sprocket teeth, the contact point moves upwards (Fig. 4) with slight elongation of the pitch to wrap the sprocket along the pitch line. Chordal Action The compatible design of HV links, joints and sprockets reduces the detrimental effects of chordal action to a minimum. The chordal action of conventional chain drives is the vibratory motion caused by the rise and fall of the chain as it engages sprocket teeth. This motion causes vibration and limits high speed load carrying capability. Of all types of chains, HV operates most efficiently at all speeds because chordal action is reduced to a minimum. Fig 5. shows how HV chain enters approximately tangent to the pitch circle of the sprocket and maintains this position as it travels around the sprocket. This smooth engagement permits high speed capabilities with efficiency and quietness. Involute Tooth Sprocket High Power in Narrow Widths The third criteria for the success of HV is the mating sprockets. An involute tooth form, differing from the straight sided teeth of conventional silent chain sprockets is designed for smooth engagement of the chain with the sprocket teeth. All HV sprockets are top-hobbed and the teeth heat treated for tough wear resistant surface. Unlike the single tooth engagement of spur gears, many teeth share the load on a HV drive, resulting in low stresses, less wear, and long sprocket life. You get more with ‘HV’ The features of ‘HV’ link design, compensating pin and rocker joint, with the involute hobbed sprockets means HV chain can transmit more power, at higher speeds, in less space than other transmission media, with smooth action and minimum of noise. High Speed Performance applications. Operating chain speeds range from 10 to 35 metres per sec. with higher speeds (to 55m/sec) on special HV chain transmits more power per inch of width than any other chain or belt drive, with Smooth Quiet Operation The rolling action of the chain joints combined with smooth sprocket engagement minimise induced vibrations. This enables HV chain to provide quiet drives on high speed applications. High Efficiency Smooth operation, with minimal frictional losses, provide transmission efficiencies up to 99.7%.

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HV Inverted Tooth Chain - 2

‘HV’ Chain - Selection CROSS+MORSE There are Seven good reasons to use HV in your design! HV transfer cases provide weight and cost savings because: 1. 2. 3. 4. 5. Fewer Shaft and Bearings are required. Lighter Loads on Shaft Bearings. Chain Bearing Loads are compressive, placing case in compression, unlike gear forces which are tensile. HV Cases are Lighter as compressive loads mean thinner sections Centre Distance is less Critical and more flexible than required by gear and belt drives. Elasticity of HV Chain accommodates normal thermal expansion, Simplified Design results in a positive...

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HV Inverted Tooth Chain - 3

HV Chain - Selection Tables (kW) The tables below provide power ratings in kW for chains of 1” width. To obtain capacity of other widths multiply width (inches) by rating obtained from table. Whilst tables cover sprockets from 21 teeth, it is recommended to use a minimum of 25 teeth for maximum chain performance and life. Preliminary selection can be made with these tables, but it is recommended that all selections should be confirmed with Cross & Morse Engineering prior to implementation. For applications with powers and/or speeds outside tables, consult Cross+Morse Engineering. 3 It is...

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