Emergency vehicle light bar assembly

An emergency vehicle light bar assembly employs first and second connected substantially horizontal elongated frames mounted transversely across the upper surface of an emergency vehicle. The connecting assembly is such that the second frame may be substantially continuously vertically displaced while maintaining parallel relationship of the frames so that the emergency indicating equipment fixed atop the second frame maintains its operational attitude regardless of the elevation to which the second frame is raised. Reciprocable operation of the connecting assembly may be accomplished by electric, hydraulic, pneumatic or manual drive systems.

BACKGROUND OF THE INVENTION 
This invention relates generally to warning lights and more particularly 
concerns emergency lights mounted on a motor vehicle. 
Presently known emergency vehicle light bars possess no satisfactory means 
for elevating the bar to heights permitting the emergency lights to be 
seen along sight lines obstructed by vehicles in the vicinity. This 
problem is of increasing concern with the rising popularity of pick-up 
trucks, vans, sport utility vehicles and other vehicles having higher than 
normal roofs. 
While a variety of devices has been developed for the elevation of 
individual light fixtures above the roof level of a motor vehicle, they 
are generally inadequate for use with modern light bars. The device must 
be strong enough to dependably support the light bar, yet have a minimum 
vertical surface area so as not to unduly increase wind resistance. It 
must be simply and quickly raised and lowered, yet durable and weather 
proof. 
Some of these known devices use telescoping tubes to support a single light 
fixture at varying heights. Such telescoping arrangements are neither 
strong enough to support a light bar nor permissive of the minimal 
elevations desired in the lower nonemergency or transport position. Other 
such devices use end pivot arrangements which are not of sufficient 
strength to dependably support a modern light bar and furthermore 
generally rotate the light fixture from a horizontal to a vertical 
condition as the pivoting arm of the device rotates from horizontal to 
vertical. 
It is, therefore, an object of this invention to provide an emergency 
vehicle light bar assembly which permits raising and lowering of the 
emergency light bar in relation to the vehicle surface on which the 
assembly is mounted. Another object of this invention is to provide an 
emergency vehicle light bar assembly of sufficient strength to withstand 
the wind forces exerted on the assembly for any height to which the light 
bar may be elevated. It is also an object of this invention to provide an 
emergency vehicle light bar assembly having a minimal lower transport 
height and a maximal elevated or emergency use height. A further object of 
this invention is to provide an emergency vehicle light bar assembly which 
maintains the light bar in the same operational attitude regardless of the 
height to which it is elevated. 
SUMMARY OF THE INVENTION 
In accordance with the invention, an emergency vehicle light bar assembly 
is provided in which a first substantially horizontal elongated frame is 
mountable transversely across the upper surface of the emergency vehicle 
and a second substantially horizontally elongated frame is connected to 
the first frame, also in transverse relationship to the emergency vehicle. 
The connecting assembly is such that the second frame may be substantially 
continuously vertically displaced while maintaining parallel relationship 
of the frames so that the emergency indicating equipment fixed atop the 
second frame maintains its operational attitude regardless of the 
elevation to which the second frame is raised. Reciprocable operation of 
the connecting assembly may be accomplished by electric, hydraulic, 
pneumatic or manual drive systems. 
In one single parallelogram embodiment, the connecting assembly consists of 
a plurality of parallel members of equal length each pivotally connected 
at one end to the first frame and at the other end to the second frame for 
rotation about parallel axes transverse to the frames. Thus, the 
longitudinal edges of the frames and the parallel members define a 
collapsing parallelogram maintaining the upper frame in constant 
substantially horizontal relationship. In this arrangement, the operating 
assembly will preferably consist of a handle fixed to one end of the 
second frame for pulling and pushing the second frame longitudinally to 
rotate the parallel members between a substantially horizontal position 
and a substantially vertical position. 
In another specially preferred double parallelogram embodiment, each of the 
frames includes a pair of longitudinal guide members fixed in spaced 
relationship by a pair of end members. Each of the frames also has a pair 
of carriages slidably engaged for longitudinal reciprocable motion along 
its respective pair of guide members. Four pairs of members of equal 
length are provided, one pair at each corner and between the frames in an 
X relationship connecting each frame at its corner to the nearest carriage 
of the other frame. Thus, as the space between each pair of carriages is 
varied from a minimal space at which the pairs of members will be in 
substantially horizontal condition to a maximal space at which the pairs 
of members will be rotated toward almost a vertical condition, the second 
frame will be raised from its lowest or transport condition to its highest 
or emergency condition. In this embodiment, the preferred operating 
assembly is a worm drive oppositely threadedly engaged between one of the 
pairs of carriages and connected to a reversing electric motor enabling 
the carriages to be variably displaced. The driven displacement of one 
pair of carriages will cause the other pair of carriages to be similarly 
displaced as the pairs of members rotate, resulting in two opposite 
collapsing parallelogram relationships. This opposite parallelogram 
configuration provides great strength which, if desired, can be further 
increased by use of a pin pivotally connecting each pair of members at the 
crossing point of their X relationship. 
In another double parallelogram embodiment of the light bar assembly, the 
frames are displaced horizontally in the minimal height configuration and 
brackets on the ends of the forward frame are connected to brackets on the 
ends of the rearward frame by pairs of arms of equal length in parallel 
relationship in vertical planes and equally offset from front to rear so 
as to maintain a collapsing parallelogram relationship defined by the arms 
and their connection points on the brackets as the arms are rotated 
between the horizontal and the vertical condition. Thus the light bar is 
maintained in its operational attitude throughout the rotational movement 
of the connecting arms between the horizontal and the vertical. In this 
embodiment, the use of a hydraulic or pneumatic system to rotate the arms 
is preferred. 
In all of these embodiments, locking mechanisms are provided to secure the 
assembly in the minimal and maximal elevated conditions.

While the invention will be described in connection with one or more 
preferred embodiments, it will be understood that it is not intended to 
limit the invention to those embodiments. On the contrary, it is intended 
to cover all alternatives, modifications and equivalents as may be 
included within the spirit and scope of the invention as defined by the 
appended claims. 
DETAILED DESCRIPTION OF THE INVENTION 
Turning first to FIGS. 1 and 2, a double parallelogram vertical 
displacement embodiment of the emergency vehicle light bar assembly 10 is 
illustrated. Upper and lower horizontal elongated frames, preferably 
mirroredly opposed, are formed from parallel longitudinal guide members 11 
and 13 connected by parallel end members 15 and 17, respectively. 
Preferably, as shown, the guide members 11 and 13 and the end members 15 
and 17 are angle irons joined at their corners. A pair of carriages 19 and 
21 is reciprocably, slidably mounted on tracks defined by the horizontal 
flange of each pair of guide members 11 and 13. As can best be seen in 
FIG. 2 illustrating one of the lower longitudinal guide members 13, the 
carriage 21 consists basically of a plate riding on the guides 13 in 
tongue and groove arrangement. The upper and lower frames are connected by 
pairs of members 23 of equal length, each member 23 being pivotally 
connected at one end to a corner of one of the frames on one of four fixed 
common parallel axes and at the other end to the nearest carriage of the 
other frame on one of four sliding parallel common axes. A worm drive 25 
connected between one of the pairs of carriages, as shown between the 
lower pair of carriages 21, is oppositely threaded at its ends so that 
rotation of the worm drive 25 in one direction causes the carriages 21 to 
be drawn into closer proximity while rotation in the opposite direction 
causes the carriages 21 to be driven apart. Preferably, a reversing motor 
27, as shown mounted to the lower frame of the assembly by an appropriate 
motor mount 29, is geared to the worm drive 25 to rotate the worm drive 25 
in either direction. 
As shown, the end members 17 of the lower frame may be further provided 
with flanges 31 to facilitate spacing of the lower frame slightly above 
the roof of the vehicle (not shown) so as to permit sliding of the lower 
carriages 21 along the lower guide members 13. In addition, spacers 33 are 
preferably provided above the end members 15 and also preferably above 
intermediate points on the longitudinal upper members 11. The spaces 33 
facilitate mounting of a light bar, such as the light bar 41 illustrated 
in FIG. 3, slightly above the upper guide members 11 so as to permit 
sliding of the upper carriages 19 along the upper guide members 11. As 
shown, the carriages to which the worm drive 25 is mounted are provided 
with worm drive mounts such as vertical plates 35 having threaded 
apertures for engaging with the worm drive 25. Preferably, the pairs of 
pivotally mounted members 23 will be connected by hinges 37, though pins 
or other pivotal arrangements could be employed. Either frame may also be 
fitted with spring clips 39 which will engage with the other frame to lock 
the assembly in a closed condition. 
In operation, as the carriages 21 are drawn into closer proximity by 
rotation of the worm drive 25 in one direction, the members 23 connected 
to the worm driven carriages 21 pivot toward the horizontal and the frame 
is pulled into closer substantially parallel vertical displacement. This 
causes the other carriages 19 to also be driven into closer proximity 
because the members 23 connecting the other carriages 19 to the opposite 
frame must also rotate toward a more horizontal condition. By operation of 
the motor 27 and therefore the worm drive 25 in the reverse direction, the 
worm driven carriages 21 are pushed further apart and the opposite frame 
is pushed upwardly. The other carriages 19 are also pulled further apart 
as their connecting members 23 approach a more vertical condition. The 
worm drive 25 also serves to lock the upper frame at the selected 
elevation. The connecting members 23 rotate in range of less than 90 
degrees from a substantially horizontal position to a position short of 
vertical. In this double parallelogram arrangement, each parallelogram is 
defined by diagonally opposite pivot points at opposite ends of opposing 
frames and at their furthermost carriages, that is by two sets of parallel 
fixed and sliding axes. This configuration provides an assembly of 
strength suitable to support the light bar at relatively high elevations 
in adverse conditions. 
Turning now to FIGS. 3 and 4, a single parallelogram rotational 
displacement embodiment of the emergency vehicle light bar assembly is 
illustrated. In this embodiment, the light bar 41 is mounted on an upper 
frame, preferably consisting of longitudinal 43 and end 41 members, such 
as angle irons, and a lower frame is formed from a similar but preferably 
mirroredly opposite arrangement of longitudinal 45 and end 49 members. As 
shown, the upper and lower frames are connected along parallel axes 
transverse to the frames by parallel members 51 of equal length pivotally 
connected to the vertical flanges of the upper and lower longitudinal 
angle irons 43 and 45 by pins 53 so that the pins 53 define a collapsing 
parallelogram. A locking rod or member 55 is pivotally connected at one 
end to a plate 57 by a hinge 59, the plate 57 being fixed proximate an end 
of one of the frames, as shown proximate one end of the upper frame. A 
stationary block 61, mounted on the opposite frame of the assembly is 
positioned so that, when the parallel members 51 are rotated to a 
substantially vertical condition, the free end of the locking member 55 
can be abutted against the stationary block 61. A handle 63, as shown 
fixed at the end of the upper frame proximate which the locking member 55 
is hinged, enables the user to pull the upper frame horizontally in 
relation to the lower frame, thus causing the parallel members 51 to 
rotate to the vertical and horizontally displace the upper frame to its 
maximum height. At least one stopping block 65, as shown mounted on the 
lower frame, is positioned to prevent an associated parallel member 51 
from rotating beyond the vertical. When the upper frame has been rotated 
until the parallel members 51 are vertical and the stopping block 65 
prevents further rotation beyond the vertical, the free end of the locking 
member 55 is abutted against the stationary block 61 to prevent rotation 
of the parallel members 51 back along their original path. Thus, the upper 
frame is locked in its maximum elevation condition. To return the light 
bar 41 to its lower position, the locking member 55 is disengaged from the 
stationary block 61 and the handle 63 pushed to cause the parallel members 
51 to rotate back to the substantially horizontal condition in which the 
upper frame of the assembly will rest on the lower frame of the assembly. 
The light bar 41 maintains the same attitude throughout the rotation of 
the parallel member 51. As shown in FIG. 1, spring clips 39 may also be 
employed in this embodiment to secure the upper and lower frames in the 
closed condition. 
Turning now to FIGS. 5 through 7, a double parallelogram rotational 
displacement embodiment of the emergency vehicle light bar assembly is 
illustrated. In this arrangement, the light bar 71 is mounted on a first 
pair of brackets 73. A second pair of brackets 75 is mounted rearwardly of 
the first brackets on the roof R of the vehicle V. Pivot pins 77 connect 
pairs of arms 79 between opposite pairs of front and rear brackets 73 and 
75 in a vertical parallelogram relationship. Thus, as the arms 79 
pivotally rotate on the rear bracket 75, the front brackets 73 are 
arcuately displaced about the rear bracket 75 while the light bar 71 
maintains a constant upright attitude throughout the rotation of the arms 
79. A pneumatic or hydraulic cylinder 81 is pivotally connected at one end 
83 to a fixed bracket assembly 75 and at its other end 85 to a brace 87 
horizontally connected between two of the arms 79 to drive the arms 79 on 
their reciprocal arcuate path. The cylinder 81 also serves to lock the 
assembly at any point desired along the path. As shown, a rest member 89 
may be mounted on the forward roof portion of the vehicle V in a position 
to support the forward bracket and light bar 71 when the light bar 71 is 
in its lowermost position. Similarly, the rear bracket 75 can be secured 
to the vehicle V by use of a mount 91 contoured to suit the configuration 
of the roof R. 
Thus, it is apparent that there has been provided, in accordance with the 
invention, an emergency vehicle light bar assembly that fully satisfies 
the objects, aims and advantages set forth above. While the invention has 
been described in conjunction with specific embodiments thereof, it is 
evident that many alternatives, modifications and variations will be 
apparent to those skilled in the art and in light of the foregoing 
description. Accordingly, it is intended to embrace all such alternatives, 
modifications and variations as fall within the spirit of the appended 
claims.