Patient lift and coupling therefor
A patient lift including a boom a spreader bar, and a friction coupling for securing the boom and the spreader bar. The friction coupling may include two friction washers disposed against respective inner faces of the boom. Two compression springs are disposed abutting the friction washers with a spreader bar support member in between. The compression springs urge the friction washers against the inner faces of the boom end. The spreader bar does not swing when the lift is moved without load. Also, the friction coupling reduces the swing of the patient, when transferred in the lift. This makes the lift easier to maneuver for the caregiver.
1. A patient lift, comprising:
a boom, the boom including at least two generally aligned boom end prongs, a spreader bar, and a friction coupling; wherein the friction coupling is received between the boom end prongs and releasably attaches a portion of the spreader bar to the boom end prongs by means of a bolt generally transverse to longitudinal axes of the boom end prongs and disposed through a transverse aperture of the spreader bar, said bolt and transverse aperture configured to allow pivoting, around a longitudinal axis of the bolt, of the spreader bar relative to the boom;
wherein the friction coupling is configured to reduce swinging of the spreader bar relative to the boom when the spreader bar is unladen;
wherein the friction coupling includes at least one friction member disposed between the boom and the spreader bar; and
wherein the at least one friction member is urged against one of the boom and the spreader bar by at least one spring directing a biasing contact with the other of the boom and the spreader bar.
2. The patient lift of claim 1 , wherein the at least one spring is embodied as a disc spring disposed around the bolt.
3. The patient lift of claim 2 , further comprising a biasing element adjacent the bolt and disposed between the disc spring and an end of the bolt.
4. The patient lift of claim 2 , further comprising a cylindrical sleeve slidably encircling a portion of the bolt between the disc spring and an end of the bolt that further comprises a bolt-end element selected from a bolt head and an adjustable nut, where the cylindrical sleeve is configured to transmit biasing force between the bolt-end element and the disc spring.
5. The patient lift of claim 1 , wherein the at least one spring is embodied as a pair of disc springs disposed around the bolt, with the bolt passing through a bore of the spreader bar and contacting the boom end prongs on either side of the spreader bar, wherein one disc spring is disposed between the spreader bar and a prong on either side of the spreader bar.
6. The patient lift of claim 5 , wherein the at least one friction member comprises at least one friction washer disposed between one of the disc springs and the spreader bar.
7. The patient lift of claim 1 ,
wherein the spreader bar includes a rod that is disposed intermediate the boom end prongs;
wherein the at least one friction member includes a first friction washer disposed encircling the bolt and contacting a first side of the rod and a second friction washer disposed encircling the bolt and contacting a second side of the rod;
wherein the at least one spring includes a first Belleville disc spring disposed around the bolt and contacting the first friction washer, and a second Belleville disc spring disposed around the bolt and contacting the second friction washer;
the bolt further comprising bolt ends each disposed outside the boom end prongs and thereby opposite boom end prong surfaces facing the rod, where said bolt ends comprise a bolt head defining a larger outer diameter at one bolt end and a nut defining a larger outer diameter at an opposite bolt end, said bolt disposed through apertures of the boom end prongs aligned with the transverse aperture of the rod; and
the bolt further comprising a biasing sleeve encircling a portion of the bolt between the nut and the first friction washer and another biasing sleeve encircling a portion of the bolt between the second friction washer and the bolt head, said biasing sleeves configured to transmit biasing force centrally along the bolt when the bolt and nut are engaged and rotated so as to advance the nut and bolt head closer together.