This light unit was developed with several objectives in mind:
1) To provide a device which produces prompt recognition of the emergency character of the vehicle. (patent lists uses for light as emergency vehicles, trucks, railway cars, etc.)
2) To provide a mechanism in which there are produced multiple movements of the light projecting device, the movements being faster in one direction than in another. This produces the impression that a vehicle using a device such as this, is moving rapidly in the mind of the observer ahead of this vehicle.
3) To provide a compact unitary device in which multiple movements of a light projecting device are produced in order to bring about new and effective warning effects.
Figure 1 is a side view in elevation and a partly vertical sectional view.
Figure 2 is a transverse sectional detail view, the section being taken at line 2-2 of Figure 1.
Figure 3 is a diagrammatic view illustrating the pattern of movement followed by this light projecting device.
The casing 10 is provided at its front with a lens supporting ring 11
for lens 12.
Within casing 10 is a bracket ring 13 which is provided with rearwardly extending lugs 14 and 15. The lugs 14 and 15 are apertured to receive the pins 16 which are fixed to casing 10 by threads. This mounting enables swinging lateral movement of ring 13 on pivot pins 16.
The ring bracket 13 is provided with centrally an on diametrically opposite sides with rearwardly extending bosses 17 which are apertured to receive pivot pins 18. These pivot pins 18 are carried by rearwardly extending ears 19 which are fixed to a reflector supporting ring 20. Fixed to the reflector supporting ring 20 is the reflector 21 carrying the light bulb socket 22. A light bulb 23 is carried by the socket 22. Current to the bulb 23 is through flexible lead connections 24.
The reflector 21 swings on the horizontal pivot pins 18 for vertical movement, while the ring bracket 13 to which the reflector structure is pivoted, swings laterally on the vertical pivot pins 16.
At the rear of casing 10 is secured a casing member 25 which supports motor 26. The motor shaft 27 extends down through the casing member 25 and is provided at its end with a worm 28. The motor shaft 27 is also fixed to a worm gear 29. The worm 28 meshes directly with a worm 30 carried by horizontal shaft 31. Horizontal shaft 31 drives, at its outer end, a disk 32. Eccentrically mounted on disk 32 is a drive pin 33 which is pivotally secured to the drive arm 34. The drive arm 34 is connected by a ball and socket joint 35 to to a bracket arm 36. Bracket arm 36 is fixed to the lower end of ring 13.
On rotation of shaft 31, a forward and backward movement of arm 34 is produced and the ring bracket 13 is caused to rotate about pivot pins 16.
Also carried by the motor shaft 27, is the worm gear 29, which meshes with the worm 37 on the horizontal shaft 38. The horizontal shaft 38 carries a driving disk 39 on which is eccentrically mounted the pin 40. Drive arm 41 is connected to the pin 42 which is carried by an angular arm extension 43 of the reflector ring 20
Movement of the arm 41 produces a movement of lever 43 which causes reflector 21 to tilt forward and backward.
The worm 30 is driven directly by the worm on shaft 27, while a
second worm 37 is driven at a much faster speed by means of the greater radius
of worm gear 29. Therefore the rotation of the motor shaft 27 produces
a slow reciprocation of arm 34 and a rapid reciprocation of arm 41. This
results in pattern indicated by the lines 44 in Figure 3. The lines
44 indicate that the reflector 21 or light bulb 23 moves upwardly
and downwardly 7 times while the reflector/light bulb is moved laterally a single time.
Therefore, there are multiple oscillations in the vertical plane during a single oscillation
in the lateral plane.
It should be understood that the casing 10 of this unit may be mounted in various ways on a vehicle so that the oscillations in one direction greatly exceed the oscillations in the other. Such resulting oscillations may be in oblique or angular positions as well as in true vertical or horizontal planes.
The new effect of this multiple or rapid movements of light projection device in one
direction during a slow or single movement of the device in the other is that there is
produced upon the the eye of the observer well ahead of the vehicle, an immediate
impression that the vehicle is approaching rapidly. The rapid vertical swinging motion of
the bulb and reflector, while at the same time being inched laterally in one direction or the
other, produces a varying light effect that is interpreted by the observer to be the result of
great speed. In other words, each vertical swinging motion of the device, accompanied
by a slight lateral movement for a few degrees, combines with the next vertical movement
of the device in producing the illusion that speed is causing a slight difference in the
light beams projected. Observers in front of an emergency vehicle carrying this device
quickly respond to the warning light, realizing that it is not an ordinary moving light
encountered in a city thoroughfare, and give the vehicle the right of way.