I need a linear actuator that can be mounted vertically to a wall or other surface and be able to support and lift about 100 lbs. Needs to be compact and preferrably AC powered and reversible.
Some sort of Acme Threaded assembly might work also. I'm not an engineer but I know enough about all this to get myself in trouble. I've looked at linear actuators and most are very expensive. I just wanted to see if some of the brighter minds out there can think of something practicle and won't break the bank.
The application is to assist a person to be elevated from near the floor to wheelchair seat height. A small seat would be affixed to the movable bed of the actuator which needs to be able to travel from about
4" inches off the floor to about 20" . The weight capacity needs to be about 150, not 100. Even more capacity would be great but that's all that's needed now and to keep costs down.
I would expect this needs to take up little real estate against the wall and may end up being mobile. Sort of a lift on a two wheeler concept.
Christ> > I need a linear actuator that can be mounted vertically to a wall or
This post is not to suggest a comprehensive solution to your problem, but to suggest that you think beyond a linear actuator. I find myself thinking of a light duty motorized scissors jack. Sort of like a motorized version of this:
The satellite dish jack/movers which have been suggested could provide a good solution, or at least a good concept worth considering.
I can't recall, but I think that 18" or 20" was the longest stroke available in the dish jack actuators.
The design consists of a screw inside two telescoping tubes. A mounting clamp is used to secure the jack's stationary section (the motor tube section). The adjustable end has an eye for affixing the moving end.
I think the jacks for the 10-12 ft. dishes may be rated at about 600 lbs, not because of the dish weight (the dishes are swung on bearings), but because the jacks need to be able to withstand wind loads of those big dishes (since many of them were solid, not screen mesh).
The motors are typically DC motors about the size of a windshield wiper motor, and may be 12, 24 or 36VDC. The gearbox reduction train doesn't need to be able to withstand any great stress because the jack screw is probably a ballscrew (low friction, mechanical advantage). I did find a Bendix motor/gearbox that utilizes an AC motor for use with the dish jack actuators.
I disassembled a flea market jack a couple of years ago, and discovered the ballscrew was working on ball thrust washers, so very little torque is required from the motor/gearbox. The ballscrew appeared to have a smooth rolled thread, and some type of treatment to produce a hard surface on the screw.
Probably not important to your application, but for positioning applications, the motor gearbox contains a feedback device for the drive circuits. The device may be a reed switch with a set of magnets arranged on a plastic disk, or a precision linear pot/resistance which varies with the length of the dish stroke.
My application would require that the platform lower to very near the floor. It appears the dish mover mounts with motor down and pushes the shaft up from the top? I don't know how I'd facilitate that.
Possible a small electric "winch" with power in/power out capabilities pulling on 4 cables going down from the support structure (seat could be on a framework with "tubes" on 4 corners, cables attached to the tubes and the tubes sliding up structure/framework tubes. HTH Ken.
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