Wednesday, September 16, 2009

GN 927 Clamping Levers with Eccentrical Cam

Diane posting today with another of our new products, our series GN 927 Clamping Levers with Eccentrical Cam.

These clamping levers are used for rapid clamping and releasing, and come in both tapped and stud types. In contrast to a clamping operation utilizing threads, these levers permit torque-free clamping. The lever has been designed to insure that its movement cannot exceed the maximum clamping position, and there are no loose components since all are assembled and mounted in their correct order.

The levers are RoHS compliant, with zinc die cast handles and a matte black plastic coated, abrasion-proof epoxy resin finish. Components are zinc plated, blue passivated steel.

These levers are available with two types of technopolymer contact plates: a fixed version, or an adjustable contact plate, with which the distance between the eccentrical cam and the contact surface is adjustable by means of a fine threaded knurled nut. The second option permits the maximum clamping force to be set by a simple adjustment. With these clamping levers, thrust forces of up to 8 kN can be obtained.

Thursday, September 10, 2009

Selecting a Crank

Diane here, and I’ve sorely neglected an essential category of machine parts, the humble but useful crank. Before these components get cranky (oh, that was bad), let’s talk about how to select the proper crank for your application.

By definition, a crank is a device for transmitting rotary motion, consisting of a handle or arm attached at right angles to a shaft. Simple enough, but there are some variables.

Balanced cranks: This type of crank has a center mounting point, which allows for smooth operation in either horizontal or vertical directions. Its design permits precise adjustment, and in applications with vibration, it will remain stationary. An example is our GN 10 series Steel Tri-Ball Handle.

Cranks: Standard cranks are mounted on one end, giving them one-handed leverage that works well for high torque applications and fast operation. They are well suited for clamping, and can be removable. Shown here is our GN 471 series Aluminum Cranks with Revolving Handle. Other options for materials for cranks are zinc die-cast, steel, stainless steel, cast iron and various plastics (nylon, phenolic, technopolymer).

Fold-Away Handle Cranks: Sometimes the application requires, for design or safety reasons, that the handle be retractable. An example is our GN 471.3 Aluminum Cranks with Retractable Handle. The handle firmly locks into position when folded or when in the operating position. We also offer styles where the handle fits neatly into a recess.

Off-Set Handle Cranks: The design of your machine may require a handle that is off-set, so that it clears obstructions when turned. Shown here is one of our DIN 468 series Off-Set Crank Handles. This cast iron crank is offered with a fixed or revolving handle, and round or square bore.

Racheting Cranks: The combination of a crank and a ratchet arm creates high torque. This mechanism also works well in a confined or limited space. The example I show here is our LR 318 series Steel Ratcheting Crank Handles.

Four-Arm Levers: A variation on the crank is the four-arm lever, which is really four cranks combined in one. This obviously increases its clamping capability. It also makes for good control with either one or two hands. Here you see our series GN 213 Four-Arm Turret Levers.

I wanted to close with a unique crank that was patented by J.W. Winco, our WRHC Nylon Plastic Retractable Hand Cranks with Revolving Handle. This cranks was designed for use in any application requiring the complete crank handle to be folded out of the way. Pretty nifty, huh?

For our entire selection of cranks, visit Section 6 of our online catalog.