If you manufacture automobile or truck steering knuckles at your plant, you need the newest patent pending fixturing system from PROHOLDŽ  to increase your overall productivity.  PROHOLD's unique design reduced the number of machine tools needed to meet production requirements from seven two-pallet horizontal machining centers down to three two-pallet machines.   PROHOLD's customer saved approximately $2 million in capital expenditures on machines and tooling by reducing the number of fixtures necessary to get the job done.   PROHOLDŽ fixturing increased overall productivity of the manufacturing process and decreased the capital investment required to obtain these gains, providing a fixture designed to eliminate chip build-up, while simultaneously making the loading and unloading of parts much easier for the operator to manage. 

This fixture utilizes a unique patent pending hydraulic expanding pullback module for clamping and securing steering knuckles, however, any kind of part designed with a through-hole in it could possibly be held with these modules.  These hydraulic expanding pullback modules can be incorporated into any fixture to eliminate chip-catching standard modular tooling components.  Using PROHOLDŽ pullback modules instead of modular tooling components provides more room on the fixture for more parts within the working envelope of the machine tool. 

The fixture below was designed to accommodate four steering knuckles - two knuckles orientated on the side of the fixture for one geometric plane of machining operations, and two knuckles on the top of the fixture for the second geometric plane of machining.  For every complete machining cycle of one pallet on the Makino A55 machine tool, two finished parts are produced off this fixture. 

Take note of the fixture shape that was designed to eliminate chip buildup.  The slanted profile of the fixture block allows chips to drop off the fixture.  This is another big advantage inherent, as much as practically possible, in all PROHOLDŽ fixturing systems.  PROHOLDŽ designs use only internally drilled hydraulic porting.  Those tubes you see in the hydraulic rotary coupling housing in right-hand picture immediately below are used to connect the machine hydraulic system to the PROHOLDŽ fixture.  You won't find a tube or tubing connection, internal or external, on any PROHOLDŽ fixture. 

PROHOLDŽ  designs its products to eliminate as many chip-catching components as possible, thereby further enhancing the ergonomic friendliness of its workholding systems.  PROHOLDŽ  also designs its fixturing systems to operate on lower hydraulic pressures, yet still provide high clamping forces.  This prolongs the service life of the hydraulic components and seals.   A new line of patent pending hydraulic clamps, soon to be incorporated into systems, provides approximately double or triple the clamping force over that of standard modular swing clamps using the same identical pressure, without the use of intensifiers, boosters, etc. 

Side view of fixture

Top angled view of fixture

Steering knuckle in position on station
(work support not installed in this picture)

Compare location with picture to the left
(work support not installed in this picture)

The hydraulic expanding pullback modules used on this fixture block provide two methods of securing the steering knuckles.   There is an expansion collet that engages the internal diameter of the knuckle and there are the pullback fingers that engage the top shoulder of the knuckle.   PROHOLDŽ expanding pullback modules can be ordered without the expansion collet where the particular application does not require its use to satisfactorily clamp the part accurately and securely for machining.  The fixture also has sequenced hydraulic work supports that automatically extend to support the link arms of the steering knuckle after initial clamping of the collet and pullback fingers. 

Locator side view of hydraulic support arm

Other side view of hydraulic support arm

The operator places the steering knuckle on the expanding pullback module.  The knuckle slides over the expansion collet and seats on the position locators, adjustable locator and/or stop supports.   The operator then applies hydraulic pressure to clamp the parts.  Clamping expands the expansion collet to engage the internal diameter of the through-hole in the knuckle and extends the fingers to engage the top shoulder of the knuckle, pulling down the knuckle against the position locators and then the hydraulic support arms extend to engage the link arms on the steering knuckle.  All four stations on the fixture are clamped simultaneously.