I think they are called a Hoist .. I've sent you an URL to look at ...I hope it's what you are looking for and it helps...
If you need assistance with a person that is bed bound, or has difficulty getting out of bed, I really suggest you contact your doctor, I'm sure they would advise you what equipment you need to use .. and may be able to assist with helping you get the proper equipment ...
If this doesn't help, please get back to us, with a little more info as to what you are looking for...