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US Pat. 3423726

MOVEABLE LIGHT FIXTURE MOUNTED ON FLAT COIL SPRINGS

by Arthur C. Heehler and George Taylor [assigned to Mercor Corporation]
Filed: Aug. 10, 1965; Serial No. 478,709
Patented: Jan. 21, 1969

One important advantage of this invention resides in the provision of a gimbal type movement to the lamp without the necessity of the four or more bearings inherent in the conventional gimbal arrangement. Furthermore, the expense of fabrication and assembly is substantially reduced and maintenance requirements such as lubrication of bearings is virtually eliminated.

Figure 1 is a front elevational view of the oscillating warning and signal light.
Figure 2 is an elevational side view of the fixture with a portion of the side wall cut away.
Figure 3 is a horizontal sectional view taken along lines III-III of Figure 2.
Figure 4 is a top plan view of a helical coil spring assembly taken along lines IV-IV of Figure 2.

Reference numeral 10 designates generally a moveable or oscillating light fixture for warning and signalling purposes. The fixture 10 comprises an electric lamp 11 which, in the illustrated embodiment, is of the sealed beam type having a lens member 12 mounted over the front of a reflector 13. The lamp unit 11 is removably mounted on an annular lamp holder 14 which is grooved at16 to receive a rim 17 of the lamp unit and includes a plurality of flexible mounting fingers 18 spaced cicumferentially therearound for easy "snap in" assembly of the lamp and lamp holder.

All four of the mounting members 38a-38d are similar and as best illustrated in Figure 4, comprise respectively a helical coil spring wound about an axis of convolution from an inner end 39 to an outer end 40. An axially extending cylindrical pin member 41 is connected in fixed assembly to the inner end 39 of the coil windings.
Springs 38 are connected in fixed assembly to the support member 32 by means of a pair of rivets 42 (or the like) such that the pin members 39 are coaxially aligned perpendicularly to the top and bottom walls (21 and 22) of the casing 20. Reduced diameter threaded portions 43 of the pins 41 of springs 38a and 38b project respectively through aperatures 44 formed in the top and bottom walls (21 and 22), and each receives a threaded nut 46 for mounting the springs on the walls of the casing and for locking the pin members 41 agains rotation.
In order to adjust the tautness of the windings of the springs, a radial end wall 47 of each of the pins has formed therein a slot 48 to accomodate a tool such as a screw driver. Therefore, by loosening the nuts 46, the windings of the springs can be tightened to substantially negate any unwinding of the springs in an axial direction.
The pins 41 of springs 38c and 38d are aligned axially transversely to the axis of springs 38a and 38b, and extend respectively through aligned aperatures 49 formed respectively in a pair of flanges 50 which extend from the flat edges 33 and 34 of the ring-shaped support member 32 in an axial direction relative to the support member. A pair of threaded nuts 46 are also applied to the threaded portions of the pins for mounting the springs 38c and 38d on the flanges 50, and the outer ends 40 of the springs are connected in fixed assembly by means of rivets 42 (or the like) to a pair of radially extending ears 51 formed at diametrically oposite portions of the annular lamp holder 14.
As a result of the arrangement of the four coiled spring mounting members 38a and 38d in mounting the support member 32 on casing 20 for pivotal movement about a first axis while substantially precluding movement of the support member 32 in a direction parallel to said first axis, and in mounting the lamp 11 on the support member 32 for pivotal movement about a second axis which is transverse to said first axis while substantially precluding movement of the lamp 11 in direction parallel to said second axis, the lamp unit is enabled to move in a manner similar to that as provided by a conventional gimble support structure which includes utilization of a plurality of bearing assemblies in journalling a pair of concentric rings to each other and a support structure to enable the smaller ring to pivot about two transverse axes.
In order to move lamp 11 through a fixed path of travel, a motor 52 is provided within the casing 20 and mounted on the back wall 26 thereof. A rotatable drive shaft 53 is connected to the shaft of the motor 52 through a suitable gear mechanism 54 and is threaded to receive a drive coupling 56 having formed therein an axially extending recess 57 situated in radially offset relation to the axis of drive shaft 53.
A generally "U-shaped" bracket 58 having a pair of outturned flanges 59 is securely fastened to the flanges 51 of the lamp holder 14 by means of suitable fasteners 60 and comprises a pair of legs 61, each of which is apertured as at 62 to receive the pins 41 of the springs 38c and 38d and to afford freedom of movement of the pins.
The bracket 58 is drivingly connected to the coupling 56 of the motor 52 by means of a ball and socket arrangement comprising a ball head 62 which is received in a bearing member 63 slidably carried in the recess 57 and which has extending therefrom, a shank 64. projecting through an aperature 66 formed in a back plate 67 of the bracket 58. An end 68 of the shank 64 is threaded to receive a nut 69 in order to connect the shank in fixed assembly to the bracket 58.