Patent GB-758526-A (GB)
Title: Improvements in or relating to oscillating and like mechanism for electric fans
IPC: F04D25/10
Filed: 1953-09-15
Abstract: 758,526. Screw fans. COLLINS, A. L. Sept. 7, 1954 [Sept. 15, 1953], No. 25488/53. Class 110(1) In an electric fan comprising a head including an electric motor and a fan rotor and mounted to turn relatively to a base, and turning mechanism driven by the motor and including an anchorage member which is held stationary by a releasable brake to render the turning mechanism operative, the brake comprises a rotor rotatable with the head and having a recess engageable by a spring-loaded plunger on the base, so that the spring allows the engagement to give way if the head in turning meets an obstruction. In the table fan shown in Fig. 1, the fan head 11 is oscillated about a base 10 by. means of a crank disc 28 driven from the shaft 14 of the fan motor 13 through worm gearing 27 and connected by a connecting rod 30 to a pin 31 on a circular abutment 32. The abutment 32 is connected by shafts 36 and 38 to a disc 37, shaft 38 being freely rotatable within a tubular stem 19 by means of which the fan head is pivotally mounted, through ball bearings 21, 22, in a tubular barrel 20 carried by a lug 24 adjustably pivoted at 25 to the base 10. A control arm 47, pivoted at 48, can be moved by a lever 49 into one of two positions, in which it is held by a resilient ball catch 51 engaging one of two holes 50. In the upper position shown, the arm 47 acts through a ball 59 and a spring 58 to press a ball 55 into one of several recesses 56 in a disc 57 integral with the tubular stem 19, whereby the fan head 11 is held stationary. The several recesses 56 provide a selection of stationary positions into which the fan head 11 can be manually turned. When the arm 47 is in its lower position, the ball 55 is out of engagement with the disc 57, and pressure is applied, through ball 45 and spring 44, to hold a ball 42 into engagement with one of several recesses 41 in the disc 37. The disc 37, and hence the abutment 32 also, is now held stationary, and the fan head 11 is oscillated about the base 10 by the crank disc 28 and connecting rod 30 reacting upon the abutment 32. If an obstacle is encountered by the fan head 11, the action of the ball 42 and recesses 41 permit the disc 37 to turn relatively to the ball 42 to prevent overturning or damage. In a modification, the crank disc and connecting rod are replaced by gear wheels (not shown) meshing with gear teeth on the periphery of the abutment 32, whereby the oscillation is replaced by a continuous rotation, the motor 13 being supplied with current through slip rings, 84a, 85a, Fig. 4, and the shaft 36b connecting the abutment 32 to a disc 37a is flexible to permit the fan head 11 to be adjusted for tilt about a horizontal pivot 72. Control is effected by a cam 97 which can be turned by a lever 49a into the position shown, wherein a ball 42a is pressed, through a ball 45a and spring 44, into engagement with one of several notches 41a in the periphery of disc 37a, whereby abutment 32 is held stationary to permit the continuous rotation of the fan head. When cam 97 is in its alternative position, ball 45a enters a segmental recess 103 to relieve ball 42a of pressure from spring 44, and a ball 59a is forced out of a segmental recess 102 into engagement with a circumferential part of cam 97 whereby spring 58 forces a ball 55a into engagement with one of several notches 56a in the periphery of a disc 57a whereby the rotation of the fan head is arrested. In another embodiment, the fan head can be tilted about a horizontal pivot 72 as described above, but the control means is similar to that shown in Fig. 1, the arm 47 being actuated, however, by pull cords; the movement of the fan head may be oscillatory or rotational. The control means may be actuated by remote control through a mechanical linkage or an electromagnetic means. In a further embodiment, the control means is similar to that shown in Fig. 1, but the abutment 32 is connected to the disc 37 by a tubular shaft which is pivotally mounted in the tubular barrel 20 by means of two ball bearings, and the fan head 11 is connected to the disc 57 by means of a tube which surrounds the tubular shaft and is pivotally connected to the latter by means of two, further ball bearings. In a yet further embodiment in which the control means is again similar to that shown in Fig. 1, the shaft 36 is eliminated, and a single disc performs the functions of disc 37 and abutment 32, the disc being connected to the fan head either by crank and connecting rod or gearing. The Provisional Specification states that a single pull cord, operating through a reversing ratchet, may be used to actuate the control means