The WDS captive clamping pin range is available with four standard handles or without a handle to allow for individual specification and features a unique spring design which guarantees its suitability for many years of re-use.
The products are perfect for use with large drill jigs, assembly jigs and machine guards, as well as any application where removable jig plates are used to speed up and simplify the machining and assembly processes, the company claims. When jig plates are loaded onto a jig bed they need to be quickly and securely clamped in position to enable accurate machining and assembly. Here, typically, a precision ground retention bush will be fitted to the plate and held in place using a standard shoulder screw. A clamping pin will then pass through the positioning hole and screw into threaded holes on the machine bed to hold the jig in place.
This is a tried and tested method for loading and unloading large jigs quickly; however, there are flaws associated with traditional products. End-users often find that the clamping pins are prone to becoming dislodged when the jig is moved, this can often result in the pin becoming lost and needing to be replaced.
The WDS range features a ‘captive’ design that ensures the clamping pins are held in place at all times, even if the jig is subjected to vibrations or turned upside down. This is achieved thanks to the positioning of a small leaf spring located in the positioning bush and a notch at the tip of the clamp’s shaft. As the clamp is removed from the jig bed the spring tightens around the notch and holds the clamping pin in place. This means that the clamp will not become accidentally dislodged.
Chris Putman, sales and marketing director for WDS, explained: “Nowadays, with the need for efficient manufacturing, a typical assembly jig can be party to multiple changes in a single shift. In this kind of environment, it is easy to dislodge and drop clamping pins into the base of the fixture. A busy engineer doesn’t have time to dig around searching for a pin so will simply grab a new one, which costs money. The captive design stops the pins from coming dislodged, adding a new level of reliability and speed to the Change of Die process.”
WDS may not be the first to develop a captive pin design, but it is the first to address a significant criticism with the traditional design. A common complaint with retained designs is that the leaf spring is prone to dislodging itself should the pin need to be removed for any reason. As the pin shaft is removed and all the pressure releases from the spring it will often fly out of the bush; at this point it’s almost impossible to find on a workshop floor and a replacement clamping pin and positioning bush will be required. This again represents an unnecessary waste which could easily be avoided.
The WDS range of clamping pins can be regularly moved from jig to jig without fear of failure year after year. It’s the first captive clamping pin that is fully self-retained.
Putman continued: “We started development on the range after a customer approached us at a trade show with the challenge to design a manufacture a longer lasting version. He told us that if we could design a product that fixed the spring glitch he would order from us in an instant. We took him up on the challenge and I’m proud to say that we succeeded. I’m even more proud of the fact that we found other ways to improve the design along the way.”
With other clamping pins on the market, both traditional and captive, there is typically a single handle choice, a T-handle. This is unsuitable in many applications where there are space restraints and engineers often find that they have to manually remove the handle themselves and fix a replacement in place (typically choosing from the vast selection of handles available in the WDS catalogue). WDS offers a choice of four handles as standard with its range: a traditional T-handle, a steel hand knob, a plastic handle or an adjustable torque knob which ensures consistent clamping forces.
The choice is further complemented with the option to specify a fitted bespoke handle from the entire WDS range, as well as the option to order a clamping pin with handle fitted. All options are available ‘out of the box’, meaning that the pins are delivered ready to go.
“Despite all of the design advantages that our product offers over the competition, they remain cost competitive compared to both retained and traditional designs on the market. In addition, because we know that each pin can be re-used many times, it’s fair to say that the expected service life is longer than other models. This means that the Total Cost of Ownership is likely to be just a fraction of traditional solutions.” Putman concluded.
The captive clamping pins have been designed to offer maximum flexibility and reliability. To further this, the clamping collar is mobile on the pin when it’s delivered. This allows the end user to modify the shaft length to fit the depth of the fixing plate – once the ideal length is found the collar can be welded in position or the shaft can be cross drilled and pinned.
The range is available in metric and imperial thread sizes, from M6 to M12 as ¼ inch to ½ inch UNC. As with all of the standard parts in the WDS catalogue, 3D CAD models are available to download free from www.wdsltd.co.uk. The parts are manufactured in-house by WDS meaning that most orders can be satisfied from stock. Parts can be ordered online or through the sales office and are available for next day delivery or collection from the WDS trade counter.
