Flexible Shaft Couplings

There are two models of Ramsey couplings, the Straight Type and the Diagonal Type. Straight Type couplings are composed of coupling halves that are split perpendicular to the shaft axis. A hardened steel silent chain joins the two halves. Diagonal Type couplings are split at an angle to the shaft axis. Due to the angular split, the chain that wraps a Diagonal couplings is loaded in shear,as well as tension. This results in Diagonal couplings having a somewhat higher load capacity than straight couplings, where the chain is only loaded in shear.

Both Straight and Diagonal chain couplings have a torque capacity that is greater than the largest diameter mild steel shaft on which it is mounted. The choice between the the two types is often determined by ease of installation in a specific application.

Straight	Diagonal

Coupling Number		Pitch & # Teeth	Min Plain Bore	Max. Bore*	A	B	C		D	E	K	Approx. Weight
Coupling Number		Pitch & # Teeth	Min Plain Bore	Max. Bore*	A	B	Straight	Diagonal	D	E	K	Approx. Weight
3AA		3/8 - 16	7/16	7/8	2 1/4	1 7/16	2 3/16		1/16	1	9/16	1 1/8 lb.
3A	3AD	3/8 - 16	1/2	7/8	2 1/4	1 7/16	2 11/16	2 11/16	1/16	1 1/2	9/16	1 1/2
4A	4AD	1/2 - 16	3/4	1 1/4	3 1/16	1 7/8	3 3/16	3 11/16	1/8	2	3/4	4
4B	4BD	1/2 - 20	3/4	1 3/4	3 11/16	2 1/2	3 3/16	3 11/16	1/8	2	1 1/16	6 1/4
4C	4CD	1/2 - 24	1	2 1/4	4 3/8	3 1/8	3 3/16	3 11/16	1/8	2	1 3/8	10
	5BD	5/8 - 20	1	2 1/4	4 5/8	3 1/8		3 3/4	1/8	2	1 3/8	10
6B	6BD	3/4 - 20	1 1/4	2 5/8	5 9/16	3 3/4	4 1/2	4 15/16	1/8	3	1 5/8	20
6C	6CD	3/4 - 24	1 1/4	3 5/16	6 1/2	4 3/4	4 1/2	4 15/16	1/8	3	2 1/8	30
8B	8BD	1 - 20	1 1/2	3 3/8	7 3/8	5	5 7/8	5 7/8	3/16	4	2 5/32	40
8C	8CD	1 - 24	1 1/2	4 1/2	8 11/16	6 1/4	5 7/8	5 7/8	3/16	4	2 3/4	60
12A	12AD	1 1/2 - 16	1 3/4	3 3/4	9 1/8	5 5/8	8 1/8	8 1/8	1/4	6	2 5/16	95
12B	12BD	1 1/2 - 20	2	5 1/4		7 1/2	8 1/8	8 1/8	1/4	6	3 1/4	105

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