Skip to main content ↑ ↓
Topic: HWH Slide with Flat Floor Operation (Read 335 times) previous topic - next topic

HWH Slide with Flat Floor Operation

Ii need some help trying to understand how the hydraulics work on on the slide with the flat floor. With the slide in the floor is flat between the slide room and the main floor. With the slide in and you push the extend button the slide will extend, when all the way out the floor will then come up so you will have a flat floor with the side room. When you press the retract button, the floor will go down and once it is down the room slide will come in.  I have included the drawing showing the parts in the system. The top two cylinders are for the room slide, the bottom two are for the operation of raising and lowering the floor.  Part AP46190 HWH calls a Valve Relief Assemble. I understand how the Sync cylinder works in a regular room slide, but don't understand Port B on this cylinder that is going to the floor. I also don't understand all of the hoses going to the bottom of the bottom left floor cylinder. I am thinking when the floor cylinders are extended the floor is up and not stored.

When the hydraulic pump is running are all of the ports for hoses pressurized, except when a valve is open it's port dumps into the storage tank?



Re: HWH Slide with Flat Floor Operation

Reply #1 –
Been searching HWH's web site and found this document. I think this will answer my questions, but not there yet.

Re: HWH Slide with Flat Floor Operation

Reply #2 –
Can't help but I'm interested in what you find.  I always enjoy watching that system work.

Re: HWH Slide with Flat Floor Operation

Reply #3 –
I'm not an hydraulics expert, but I did stay at a Holliday Inn Express last night. And I do know a bit about how hydraulics work, and I think I'm reading this right, and I love trying to figure out how stuff like this works.

With the pump running and solenoid B on (Extending the room) Oil flows into the sync cylinder and shifts it to the right side. This opens port A to the lines going to the room cylinders. Pressure is applied on the rod end of the cylinders to retract them. As they retract, the oil in the head end of the cylinder is flowing out the port at the top and going through line K to port D on the Main Floor cylinder. The pressure needs to be 1100 to 1300 psi to open the check valve at the top of the cylinders to allow the oil out. That oil then goes into port D on the Main Floor cylinder. Since the floor cylinders are extended and the floor is down, the plunger gets pulled up and oil is allowed to go from D to C and back to the valve and into the tank. Once the room cylinders  are fully retracted, the pressure will rise because the oil has no where to go. Once it gets to 2500 psi, it will open the check valve and provide flow to port A on the floor cylinders. This causes the floor cylinders to retract, closing the connection from D to C and retracting the cylinders lifting the floor. The oil in the head end of the cylinders exits port B and goes to port B on the sync cylinder and since the rod is all the way to the right in the sync cylinder, the check ball moves and port B is connected to C and then back to the valve, through solenoid B to the tank.

To move the room in, Solenoid B is off and Solenoid A is on. This provides flow to port A and B of the valve. The oil goes out B into port C of the sync cylinder. The oil flows through the check valve to port B, through the flow limiter into port B of the Floor cylinders. This causes the floor cylinders to extend and lower the floor. The oil from the rod side of the floor cylinders flows up to the check valve and has no resistance going back through that valve back to port A of the control valve. It then meets the pump flow and combines to go back to B. The pressure at B will be less than the pressure at A. The pressure at B is on the head side of the cylinder, the pressure at A is on the rod side. The area difference in the sides make the pressure difference. Once the floor cylinders fully extend and retract the plunger, Oil can flow from C to D in the Main Floor Cylinder and go up to the room cylinders, past the check valve and extend the cylinders and retracting the room.

I love the ingenuity behind some of these hydraulic designs and how such complex operations were accomplished. A more modern way of doing this would be to just have simple cylinders and electronics controlling it. Limit switches would let the controller know when the cylinders were at their limit and that it needed to actuate the next set. At least until the switch fails, or gets out of adjustment, or a mouse eats a wire, ETC.  But the cylinders would be much less expensive and simpler.
 

Re: HWH Slide with Flat Floor Operation

Reply #4 –
Thanks kgrover, after I found the document in reply 1 I had to leave and had not tried to figure out the flow. When I get to my computer with large monitor I will track your flow.

I bet the engineer that designed that was proud of himself after coming up with that system.

I am thankful that there are no electronic to go wrong.