Captive products consist of two parts; a pin and a bushing. This design eliminates the need for wire rope lanyards, or other retention devices, to retain the pin with the tool. In fully retracted position, the bushing's spring clip snaps into the pin's radial groove. This holds the pin fully retracted by spring force and positively prevents removal. Spring pressure also holds the pin in intermediate extended positions, an advantage especially if the fixture is turned upside down. Precision ground bodies of the pins and tightly tolerance bushings provide high precision locating.
Captive Products come in a variety of styles. Some are only locating pins, while others have threaded ends to provide both Clamping and Locating. They are also available with a variety of Knobs, Cap Screw Heads, and Handles.
Unique Features
Radial Groove & Spring Clip
The Depth of the radial groove, and the size of the spring clip, determine the amount of retention force on the pin. Too much force can provide false signals to the operator in regard to the pin position while too deep of a radial groove will weaken the pin. Spring clips and radial groove size & depth can be customized for specific customer applications.
Thread-Stop Style
Standard Threaded versions of Captive Products are fully threaded. This allows for maximum clamping range after minimum thread engagement. When utilizing the Thread-Stop style care must be taken to ensure that minimum thread engagement will be achieved as the clamping range, what might also be called the length of adjustability, is decreased by the presence of the Thread-Stop. (see image below.)
The advantage offered by the Thread-Stop is this feature ensures that the pin cannot be removed from the tool without first removing the spring clip.
Threads
Single-Lead threads are standard for most Captive Products as they provide excellent resistance to loosening. A Double-Lead thread option is available for some Captive Product Styles. This option provides fastening twice as fast as single lead threads and may be appropriate for applications which require frequently tightening and loosening.
Locking-Pin Bushings for Captive Products are equipped with a retainer spring clip on the inside diameter, for use with all types of locking/captive pins and locating screws. These precision bushings are designed to press fit in a standard reamed hole, and can be secured with a Lockscrew to positively hold the bushing in place. Also available in a threaded version, with an externally threaded shank for installation in a tapped hole. This threaded design are handy when captive clamping pins are used in non-locating applications.
Given the plethora of features found in these items it is unlikely that any vendor will have a solution for every tooling challenge. Carr Lane Mfg has created a configurator that allows designers to mix-and-match these features; including special features, into a single item. The CLM configurator also creates a solid model for use in most CAD programs for easy integration into tool designs.
