So in the above picture you can see the business end of the PE 4500 in all its glory. It looks pretty packed huh? This is definitely one to file under "good things come in small packages" because for all the stuff that's in here, it's actually really accessible to work on. On the left side you can see the lift pump motor (silver with black cables) and fluid reservoir (black). This pairing also has a dedicated modular solenoid on it, so if it happens to die on you, you can replace that part alone and not the entire lift power unit. On the right is a bunch of stuff, but most importantly are the brains of the unit, a Crown Access 3 module, contactor, and fuse. Along with that is the always important horn, and hiding behind that at the top is the truck's side of the battery connector. One note we want to call out especially is the brakes on PE 4500. Unlike some of Crown's competitors, these electromagnetic brakes default to on. Part of the regenerative braking that keeps Crown's trucks so energy efficient, these default on brakes means that if for some reason your truck loses power, it stops right away. We had a customer switch their fleet to PE 4500 trucks because their previous brand used power to keep the brakes on, so if they lost power the truck just... kept going. A safety nightmare given how fast these things can move when loaded for sure! In the middle of all of this is where the machine gets its movement from. Pictured to the right here in a cut-away view, a powerful AC drive motor is mounted across the pivoting control tiller, housed within a hefty steel enclosure that also protects the gears and drive axle for the truck. Not content with some sort of flimsy gearing or power transfer system, this entire assembly rotates to help turn the unit, with roller mounts built directly into the bottom of the drive unit, and heavy duty bearings above. This all mounts into a heat treated roller race that bolts to the frame of the lift to keep things solid (it's a ring of steel almost 2"/5cm thick and weighs about 22lbs/10kg). Keeping this all as a single unit means fewer stresses in transmitting the drive power to the rest of the unit, and gives it a reassuringly solid feel when in use. This center of mass also helps to cushion users against some of the shocks and rattles that working in a dock environment bring, meaning your staff can work better for longer. Because it is fully modular, almost all of these components can be replaced individually as well. Rollers, bearings, and drive shafts get worn before anything vital can get damaged, and the thickness of the components means they can take the kind of abuse that working in a dock environment can dish out. Because of their location, all of these parts will give some kind of warning when they start to fail; be it a wobble in the steering or a wiggle in driving. Attentive users and a Planned Maintenance contract will both help your notice these warning signs and correct them before they become a major problem or cause an accident. Also because of this, it allows us to only replace what needs to be done instead of having to replace more costly full assemblies.
So if you've been reading these Focus On articles for a while, or even just the ones about walkie-jacks, you probably think the image to the left looks a little familiar, and you'd be right! The WP 3000 and the PE 4500 share a lot of design genes between them, but they're more kissing cousins than siblings. Think of the PE 4500 as the WP 3000 dialed up to 11.
More steel, heavier components, more steel, more shielding, more lift, and did we mention more steel? Because the PE 4500 is more bulky than its little cousin, Crown was able to beef up the design in basically every way. Starting at the fork tip we have entry rollers to aid in getting the forks where they need to be as well as easing that initial entry shock a bit for both the load and your operators. Behind that you can see a very similar, but again much beefier load wheel riser and shackle system. Connecting this to the tension bars is a tenon responsible for much of the work this truck does. Lots of work means lots of abuse, and Crown provides a kit for replacing these when they do eventually fail. This means all the worn components get replaced at an economical price to get your truck back to work faster. Bracketing all of these are reinforced forks with more than just the C-beam that the smaller jacks have, and instead we have fully enclosed edges for more strength.
Further back where the forks meet the rest of the unit are hardened steel wear plates to protect your machine from dock plates and the jostles that come from being in and out of trucks constantly. These help protect the lift linkages just behind them, cutting down on replacement costs. The downside here is that if you ever somehow wear them down, you need a welder to replace them (or to replace the entire front half of the truck, getting new forks). The upside is that if you've used your truck that much, it's probably time for a new one!
Next up you can make out the roller race I walked about earlier. Safe in the core of the truck, it provides a rock solid guide for the drive unit to rotate within. Securely fastened to the frame, it too is a modular part so if roller replacement gets neglected a bit and the ring gets damaged, you can just install a new one instead of having to scrap the truck because of frame damage. All around this core you can see reinforced gussets and steel stringers. Not only does this protect your truck, but it helps protect your people too! The platform is built to protect both, and has to take a huge impact before it crumples in a meaningful way. Also down here you can see the heavy duty caster assemblies. Designed to take the wobble out of running and cornering, these adjustable, heavy duty casters are as modular as the rest of the PE 4500. While this makes it easier to replace wheels and axles when they get worn enough, it also means that the entire assembly can be replaced with a single kit once the cumulative wear starts to damage the housing and other components. Like we've talked about before, these caster wheels share the same 200/300/400 rating system that crown uses for all their load wheels, and finding the right wheel compound can have a significant impact on how often they'll need replacing.