Built to last.
The J3 back has been subject to rigorous testing. Detailed below are the methods used when testing the new J3 back.
Testing procedure for the J3 back.
How did Sunrise Medical test the J3 back?
Sunrise Medical lifecycle tests all of its backs. The test involves punching a 180lbs force against the middle of the back for 100,000 cycles. This simulates a 300 pound individual applying a load against the back in a fully reclined position. The back hardware experienced no failure or slippage. In an upright position, this amount of force would be almost impossible, much less repeated 100,000 times. The J3 back hardware displayed exceptional strength as validated by testing.
Please note, all fasteners were checked with a torque wrench before testing.
What happened when the hardware was mounted low on a tall back?
The test described above was then run with the hardware bracket offset 9cm below the centre of the push force. The hardware again passed the test without damage, failure or slippage. This same test is used for all Jay back products
Is the J3 Back crash tested?
Yes. The J3 back was subjected to a series of standard ANSI/RESNA transit hardware crash tests at the University of Michigan's test facility. The hardware easily withstood rebound forces of over 500lbs from the test dummy. In fact, when the chair was examined after the tests, engineers found that the back canes had been bent, but the J3 back hardware was unaffected. The hardware was so strong that it was able to bend the back canes without any sign of damage.
Hardware play and mounting advice.
Why is proper hardware mounting important?
The most important consideration relative to long term durability is proper attachment. When the J3 back is shipped, the hardware is intentionally kept loose so it is easy for dealers, RTS's and technicians to make fitting adjustments. Here are some tips to ensure that the hardware stays in position once the correct fit is located:
- Make sure all the bracket adjustment nuts are really tight, using the long handled wrench provided.
- When the hardware fasteners are tightened, they need to be alternately tightened (for example, tighten one bolt and then tighten the other, then go back to the first bolt and then back to the second etc..) until the fastener is secured. Just like a car tyre, when the second (opposite) bolt is tightened, additional threads will open in the first bolt.
Is hardware play bad?
Many make the assumption that hardware play is an indicator of poor durability. This is not the case. A slight gap in the pin placement is designed to ensure that the back is easy to remove and attach. This creates a small amount of pre-load play. Once an individual actually sits in the chair and puts the hardware under load, this play is minimised and all that remains is a slight flex in the receivers. This flex exists because the J3's lightweight nylon plastic receivers are elastic, which is a very effective way of dealing with repetitive weight loads over long periods of time.