Dual-strap hoisting device and patient lift apparatus comprising the same

There is in particular described a hoisting device (50) for a patient lift apparatus (1), comprising first and second lifting straps (50a, 50b) configured to selectively lift or lower a patient, first and second winding spools (WA, WB) configured to allowing winding or unwinding of the first and second lifting straps, respectively, and a driving arrangement configured to drive the first and second winding spools (WA, WB) so as to selectively wind or unwind the first and second lifting straps (50a, 50b). The driving arrangement comprises a first electric motor (MA) in driving connection with the first winding spool (WA) and a second electric motor (MB) in driving connection with the second winding spool (WB), the first and second electric motors (MA, MB) being operable in synchronism to wind or unwind the first and second lifting straps (50a, 50b). The hoisting device (50) further comprises a first guide roller (70A) whose circumferential surface contacts a first side of the first lifting strap (50a) and a second guide roller (70B) whose circumferential surface contacts a first side of the second lifting strap (50b). Each of the first and second guide rollers (70A, 70B) is supported by a one-way bearing configured such that each of the first and second guide rollers (70A, 70B) is forcibly driven into rotation upon unwinding of the associated lifting strap (50a, 50b) from the associated winding spool (WA, WB) and is free to rotate in an opposite direction upon winding of the associated lifting strap (50a, 50b) onto the associated winding spool (WA, WB). Each of the first and second guide rollers (70A, 70B) is forcibly driven into rotation upon unwinding of the associated lifting strap (50a, 50b) from the associated winding spool (WA, WB) such that a tangential speed of the circumferential surface of each of the first and second guide rollers (70A, 70B)is greater than an effective tangential speed at which the associated lifting strap (50a, 50b) is unwound from the associated winding spool (WA, WB).