U.S. patent number 3,899,843 [Application Number 04/830,908] was granted by the patent office on 1975-08-19 for signalling device with a sign having provision for spilling of wind and with a support.
This patent grant is currently assigned to Western Progress, Inc.. Invention is credited to Robert L. Doyle, Montgomery C. Swezy.
United States Patent |
3,899,843 |
Doyle , et al. |
August 19, 1975 |
Signalling device with a sign having provision for spilling of wind
and with a support
Abstract
Signalling device comprising a sign and a support with the sign
being formed of flexible material and having rigid extension arms
which are yieldably urged into position for supporting the sign and
which will bend with a predetermined wind load on the sign to
facilitate spilling of the wind past the sign. Means is provided
which will prevent bending of the sign beyond a predetermined
amount when wind is being spilled by the sign. The support has an
eccentrically mounted cam for retaining the support stand in an
erected position. The stand also includes pin and slot means for
preventing rotation of the telescoping parts of the stand. A
bracket having swivel mounted jaws is provided for fastening the
sign to the telescoping members.
Inventors: |
Doyle; Robert L. (Palo Alto,
CA), Swezy; Montgomery C. (Palo Alto, CA) |
Assignee: |
Western Progress, Inc.
(Mountain View, CA)
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Family
ID: |
27104435 |
Appl.
No.: |
04/830,908 |
Filed: |
May 8, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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689514 |
Dec 11, 1967 |
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Current U.S.
Class: |
40/602; 40/603;
40/612; 116/63P; 160/351 |
Current CPC
Class: |
G08B
5/00 (20130101); E01F 9/688 (20160201); G09F
7/18 (20130101); G09F 2007/1813 (20130101) |
Current International
Class: |
G08B
5/00 (20060101); G09F 7/18 (20060101); E01F
9/012 (20060101); E01F 9/011 (20060101); G09f
007/18 () |
Field of
Search: |
;40/125R,125N,125F,125G,125H,128,129C,129R,145A ;116/63R,63P
;160/351 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Michell; Robert W.
Assistant Examiner: Pitrelli; John F.
Attorney, Agent or Firm: Flehr, Hohbach, Test, Albritton
& Herbert
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No.
689,514, filed Dec. 11, 1967, now abandoned.
Claims
We claim:
1. In a signalling device, a flexible sheet-like member, first and
second arms, means pivotally interconnecting said first and second
arms intermediate the ends of the same, said second arm having a
length substantially less than the length of said first arm, first
and second extension arms, means yieldably mounting said first and
second extension arms on said second arm so that said first and
second extension arms are normally disposed in alignment with said
second arm, and means securing said sheet-like member to said first
arm and to said first and second extension arms to support said
sheet-like member in a relatively taut condition and so that at
least portions of the sheet-like member are carried by the
extension arms, said yieldable means permitting bending of portions
of the sheet-like member when a predetermined wind load is placed
on the sheet-like member to permit spilling of wind by the
sheet-like member.
2. A signalling device as in claim 1 wherein said yieldable means
includes a coil spring in the form of a right cylinder mounted on
the outer ends of the second arm and mounted on the inner ends of
the extension arms.
3. A signalling device as in claim 1 wherein said yieldable means
includes means for preventing bending of the yieldable means beyond
a predetermined angle.
4. A signalling device as in claim 1 wherein said yieldable means
consists of first and second coil springs in the form of right
cylinders, said first and second coil springs being mounted on the
outer ends of the second arm and serving to carry the inner ends of
the extension arms so that the extension arms are maintained in
alignment with said second arm, first and second strap-like members
mounted on the outer ends of said second arm and having hook-like
portions adapted to engage the ends of the spring remote from the
outer ends of said second arm, and third and fourth flexible
members secured to the inner ends of the extension arms and having
hook-like portions adapted to engage the ends of the spring remote
from the inner ends of the extension arms, said hook-like members
on said first, second, third and fourth members being formed so as
to permit only limited bending movement of the springs.
5. In a signalling device, a diamond-shaped, flexible, sheet-like
member having signalling indicia on one side thereof, pocket
elements arranged at the corners of said sheet-like member, means
comprising cross-arm members constructed so that the ends thereof
may be received in said pockets serving to maintain said sheet-like
members in a taut condition, means pivotally interconnecting said
cross-arm members so that the same may be moved from a generally
aligned inoperative storage condition to a right-angled
intersecting display condition in which one arm is vertical, at
least one of said cross-arm members being resiliently yieldable in
planes normal to said sheet-like member and yieldable in response
to wind loadings on said sheet-like member to afford wind spilling,
and a support stand engaging the vertical one of said cross-arm
members.
Description
BACKGROUND OF THE INVENTION
In U.S. Pat. No. 3,200,786 there is disclosed a signalling device
which has been found to be particularly effective. However, it has
been found that the signalling device may blow over in high winds
encountered on construction projects, particularly in certain
geographical areas. This is particularly true when the large
diamond-shaped 48 inches .times. 48 inches signs are utilized which
are required on many Federal highway programs. There is, therefore,
a need for a new and improved signalling device.
SUMMARY OF INVENTION AND OBJECTS
The signalling device includes a sign with a support stand. The
sign is formed of a flexible sheet-like member. At least one arm is
provided that is formed of a rigid material. In addition, an
extension arm, also formed of rigid material, is provided.
Yieldable spring means is provided for mounting the extension arm
on the first named arm and serves to normally retain said
additional extension arm in alignment with said first named arm.
Means is provided for securing the sheet-like member to said first
named arm and said additional extension arm so that the sheet-like
member is maintained in a relatively taut condition. When a
predetermined wind load is placed on the sign, the spring means
yields to permit bending of the sign and to facilitate spilling of
wind past the sign. Means is provided on the sign for preventing
bending of the sign beyond a predetermined amount when it is
spilling wind. The support stand has telescoping members. Means is
provided on the telescoping members for preventing rotation of the
sign when it is mounted thereon.
In general, it is the object of the present invention to provide a
signalling device which has a sign having provisions for spilling
of the wind.
Another object of the invention is to provide a signalling device
of the above character in which the arms provided for maintaining
the sign in a relatively taut condition are provided with yieldable
spring means to permit bending of the sign to facilitate spilling
of the wind past the sign.
Another object of the invention is to provide a signalling device
in which means is provided for preventing bending of portions of
the sign beyond a predetermined angle from a normal position when
wind is being spilled by the sign.
Another object of the invention is to provide a signalling device
of the above character in which the support stand is provided with
means for preventing the stand from collapsing as it is rocked back
and forth in the wind.
Another object of the invention is to provide a signalling device
in which the support stand includes telescoping members and in
which means is provided for preventing rotation of the telescoping
member which has the sign fastened thereto.
Another object of the invention is to provide a signalling device
of the above character in which the clamp utilized for securing the
sign to the support stand includes pivotally mounted jaws to
facilitate gripping of telescoping members of various sizes.
Additional objects and features of the invention will appear from
the following description in which the preferred embodiment is set
forth in detail in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a signalling device incorporating
the present invention.
FIG. 2 is an enlarged rear elevational view of the sign shown in
FIG. 1.
FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG.
2.
FIG. 4 is an enlarged cross-sectional view taken along the line
4--4 of FIG. 2.
FIG. 5 is a cross-sectional view looking along the line 5--5 of
FIG. 2.
FIG. 6 is a cross-sectional view looking along the line 6--6 of
FIG. 1 and particularly shows the clamp utilized for securing the
sign to the support stand.
FIG. 7 is an end elevational view of the clamp shown in FIG. 6.
FIG. 8 is a cross-sectional view taken along the line 8--8 of FIG.
1.
FIG. 9 is a cross-sectional view taken along the line 9--9 of FIG.
8.
FIG. 10 is a cross-sectional view taken along the line 10--10 of
FIG. 1.
FIG. 11 is a cross-sectional view taken along the line 11--11 of
FIG. 10.
FIG. 12 is a cross-sectional view similar to FIG. 3 showing another
embodiment of a sign incorporating the present invention.
FIG. 13 is a partial rear elevational view of the sign shown in
FIG. 12.
FIG. 14 is a cross-sectional view taken along the line 14--14 of
FIG. 13.
FIG. 15 is a cross-sectional view taken along the line 15--15 of
FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The signalling device 21 constituting the present invention
consists of a support stand 22 with the sign 23 mounted thereon. A
yoke 24 is also mounted upon the support stand and carries a
plurality of warning flags 26.
The support stand 22 has three telescoping sections 27, 28 and 29
in which section 27 is the lower section. The intermediate section
28 telescopes into section 27 and the top section 29 telescopes
into the intermediate section 28. The lower section 27 and the
intermediate section 28 are both provided with collets 31 (see FIG.
10) which are mounted by suitable means such as a press fit in the
section. The collets are provided with deformable extensions 32
having inclined surfaces 33 adapted to be engaged by inclined
surfaces 34 carried by knurled ferrules 36 threaded onto threads 37
provided intermediate the ends of the collets 31. It can be readily
seen that by tightening the ferrule 36, the tube which telescopes
therein can be held in any desired elevated position by frictional
engagement between the collet and the tube or section.
Means is provided for preventing rotation of the intermediate
section 28 with respect to the lower section 27 and takes the form
of a pin and slot means in which slots 39 are formed in the lower
extremity of the collet 31 mounted in the upper end of the lower
section 27 and a pin 41 is mounted on the lower extremity of the
intermediate section or tube 28.
In use, the section 28 is extended as far as possible so that the
pin 41 engages the lower extremity of the collet 31 and thereafter,
the section 28 is rotated while at the same time lifting the same
until the pin 41 seats within the slots 39 provided in the collet.
Then while holding section 28 in this position, the ferrule 36 is
tightened to retain section 28 in this extreme extended position
with the pin 41 seated in the slots 39. When the intermediate
section 28 is positioned in this manner, it can be seen that the
intermediate section 28 cannot rotate with respect to the section
27 for the purpose hereinafter described.
The support stand also includes four legs 46 which are formed of a
suitable material such as angle iron. The legs are pivotally
connected to a collar 47 by rivets 48. The collar 47 is slidably
mounted upon the lower section 27. Braces 49 are pivotally
connected to intermediate portions of the legs 46 by rivets 51 and
are also connected to a collar 52 affixed to the lower extremity of
the lower section 27 by rivets 53. With the construction shown, it
can be seen that the legs 46 can be collapsed so that they extend
generally parallel to the lower section 27 merely by sliding the
collar 47 upwardly on the lower section 27.
Means is provided for preventing the collar 47 from sliding
upwardly on the tube 27 and consists of a knurled circular member
or cam 56 which is mounted upon a pin 57. The cam 56 is disposed
between a pair of spaced parallel ears provided on the collar 47
and pin 57 is mounted in the ears. It will be noted from FIG. 8
that the knurling extends in a direction which is parallel to the
axis of the cam. As can be seen particularly from FIGS. 8 and 9,
the cam is adapted to engage the lowermost section 27 and when in
engagement therewith prevents the collar 47 from riding up on the
lower section 27. It is only when the cam 56 is pivoted out of
engagement with the lower section 27 that the collar can be moved
upwardly to collapse the legs 46.
The sign 23 consists of a flexible member or sheet 61 formed of a
suitable material such as a heavy canvas coated with plastic or the
like. The sheet can be formed in the general manner described in
U.S. Pat. No. 3,200,786 and can bear indicia on its front side. It
also can have the configuration described in U.S. Pat. No.
3,200,786, namely rectangular or diamond-shaped as shown in FIG. 1.
Pockets 62 and 63 are formed on the upper and lower corners on the
back side of the sheet or member 61 of the type also described in
U.S. Pat. No. 3,200,786. As described therein, the pockets can be
formed by sewing additional pieces 64 of material to the rear of
the sign by sewing on one side and the upper extremity of the same
to the sheet 61 to provide a pocket which is open on one side. A
snap 66 is provided for fastening the other side of each pocket so
that only one side of the pocket is open. Additional pockets 67 are
formed on the two other corners of the sheet 61 by taking pieces of
material and folding them over and sewing the ends together and to
the corners of the sheet 61.
Means is provided for retaining the sheet or member 61 in a
relatively taut condition and consists of a pair of arms 71 and 72
which are pivotally interconnected to each other intermediate the
ends of the same by suitable means such as a rivet 73. As can be
seen from FIGS. 2, 3 and 4, the arm 72 is relatively short in
comparison to the arm 71. Additional extension arms 74 are provided
for mounting on the opposite ends of the arm 72. The arms 71 and 72
and the extension arm 74 are all formed of a suitable rigid
material such as steel. Yieldable means is provided for mounting
the extension arms 74 on the arm 72 so that the extension arms are
maintained in alignment with the arm 72 and consists of coil
springs 76 in the form of right cylinders which have one end of the
same fixed to the arm 72 by a rivet 77 and the other end of the
same affixed to the extension arm 74 by a rivet 78. As can be seen,
particularly in FIG. 4, the ends of the arm 72 and the inner ends
of the extension arms 74 extend into the coil springs 76. In this
manner, the coil springs 76 serve to normally retain the extension
arms 74 in alignment with the arm 72.
The springs 76 are constructed so that they will yield when a
predetermined pressure is applied to the arms 74 as, for example, a
force of 36 pounds applied to the ends of the extension arms 74
will cause the springs 76 to permit the arms 74 to be bent relative
to the arm 72. The extension arms 74 are secured in the pockets 67
by rivets 79. Thus, it can be seen that the arm 72 with the
extension arms 74 are permanently secured to corners of the
sheet-like member 61 to retain it in a taut condition. A loop 81 is
sewn to the rear side of the sheet-like member and overlies the arm
72 and keeps the center of the sheet-like member in relatively
close proximity to the arm 72. The arm 71 is adapted to be removed
and inserted in the pockets 62 and 63 and is adapted to be moved to
a position which is in line with the arm 72 and the extension arms
74 so that thereafter the sheet-like member 61 can be rolled about
the arms.
A clamp 86 is secured to the sign 23 and is provided for removably
affixing the sign to the support stand 22. The clamp 86 consists of
first and second U-shaped parts 87 and 88. The two parts 87 and 88
are pivotally interconnected by a screw 89 which has as its head 91
pivotally mounted in the part 87 by a rivet 92. The screw 89
threads into a nut 93 pivotally mounted in the part 88 by a rivet
94. The other ends of the parts 87 and 88 are adapted to be
interconnected by a screw 96 which has its head 97 pivotally
mounted in the part 87 by a rivet 98. A wing nut 99 is threaded
onto bolt 96 and is adapted to engage the part 88 through which
bolt 96 extends. The parts 87 and 88 are provided with arcuate
recesses 101 intermediate the ends of the same which are slightly
larger than the size of the tubular member which is to be grasped.
A plurality of four jaw-like members 102, 103, 104 and 105 are
provided with two of the jaw-like members being pivotally mounted
at spaced points adjacent the arcuate openings 101 by rivets 107.
Each of the jaws is provided with serrated arcuate surfaces 108
which are adapted to engage the tubular section 28.
Use of the signalling device may now be briefly described as
follows. In placement of the signalling device, the support stand
22 is first erected by lifting the lower section 27 upwardly to
permit the legs 46 to open outwardly under force of gravity. As
soon as the collar 47 has been moved to its lowermost position, the
eccentrically mounted member 56 is raised upwardly and moved into
engagement with the section 27 to prevent the collar 47 from
slipping upwardly on the section 27. Thereafter, the intermediate
section 28 is raised until the pin 47 strikes the lowermost
extremity of the collet 31. The section 28 is then rotated until
the pin 47 comes into engagement with the slots 39 in the collet
31, and thereafter the ferrule 36 is tightened to cause the collet
31 to frictionally engage the intermediate section 28. The top
section 29 is then raised and secured in the desired position by
the ferrule 36 mounted on the upper end of the intermediate section
28. Means for preventing rotation is not provided for the top
section because the sign 23 is mounted on the intermediate section
28. The yoke 24 can be mounted at the top of section 29 and the
flags 26 put in place.
Thereafter, the sign 23 can be unrolled and then the arm 71 can be
rotated relative to the arm 72 and positioned within the pockets 62
and 63 and the snaps 66 closed. All four corners of the sheet-like
member 61 are now engaged by the arms which serve to retain the
sheet-like member 61 in a relatively taut condition.
The sign is now ready to be clamped onto the support stand. The
parts 87 and 88 are opened up by loosening the wing nut 99 and
swinging the wing nut out of the way. Thereafter, the open parts 87
and 88 are slipped over the intermediate section 28 so that
intermediate section 28 is seated within the recesses provided by
the jaw 102-105. The bolt 96 is then swung into position and the
wing nut tightened so that the jaws 102-105 firmly grip the section
28. It has been found that since the jaws 102-105 are pivotally
mounted within the parts 87 and 88, they are able to accommodate
telescoping sections of various sizes and still firmly grip the
same. The serrations provided in the jaws prevent rotation of the
sign relative to the intermediate section 28. As hereinbefore
pointed out, the section 28 cannot rotate with respect to the
bottom section 27 because of the pin and slot connection
provided.
Let it be assumed that the signalling device has been placed in a
location where a substantial wind is encountered. When the wind
exerts pressure on either or both sides of the sign which exceeds a
predetermined maximum amount as, for example, a wind velocity which
places a force on the extension arms 74 which is greater than a
predetermined amount as, for example, 30 to 36 pounds, the sides of
the sign will bend to facilitate spilling of the wind past the
sign. As shown in FIG. 4, this bending occurs when either or both
of the springs 76 yield. As soon as the force applied by the wind
drops below the predetermined amount, the sides of the sign 23 will
immediately spring back to their normal position in which the front
surface of the sheet-like member 61 is substantially planar. Thus,
it can be seen that the springs 76 serve to provide means which
permit bending of the sign to facilitate spilling of the wind.
This is very advantageous because this makes it possible to utilize
the signalling device in very windy locations without any danger of
it being tipped over by the wind. It has been found that this
feature greatly enhances the stability of the device. Because of
the locking features hereinbefore provided, the sign 23 does not
turn. In addition, the cam 56 prevents the collar 47 from
accidentally moving upwardly as, for example, when the signalling
device is being rocked by the wind to decrease the stability of the
signalling device.
By way of example, it was found that a signalling device
constructed in accordance with the present invention having a
sheet-like member measuring 48 inches .times. 48 inches was able to
withstand a wind velocity of over 35 miles per hour without any
difficulty. It has been found that the springs which prevent
bending of the extension arms 74 with respect to the arm 72 readily
permit spilling of sufficient wind so that the device can be
utilized in windy locations.
Another embodiment of a sign 121 similar to the sign 23 is shown in
FIGS. 12-15 in which a flexible member or sheet 61 substantially
identical to that hereinbefore described is utilized. The means
which is provided for retaining the sheet or member 61 in a
relatively taut condition consists of a pair of rigid arms 122 and
123 which are pivotally interconnected to each other intermediate
the ends of the same by suitable means such as a rivet 124. The arm
123 is relatively short in comparison to 122. Additional extension
arms 126 and 127 are provided for mounting on opposite ends of the
arm 123. The arms 122 and 123, as well as the extension arms 126
and 127, are formed of a suitable rigid material such as steel.
Yieldable means is provided for mounting the extension arms 126 and
127 on the opposite ends of the arm 123 and to maintain them in
alignment with the arm 123 and consists of a pair of coil springs
128. As can be seen particularly from FIG. 14, the coil springs 128
have a substantial length and have an internal diameter so that the
outer end of the arm 123 and one end of the associated extension
arm as, for example, extension arm 126, can be positioned within
the coil spring 128 in such a manner that the extension arm 126 is
held in alignment with the arm 123. As shown particularly in FIG.
14, the coil spring 128 has an inner diameter which is only
sufficiently great so that the largest cross-sectional dimension of
the arm 126 will slidably fit within and frictionally engage the
coil spring 128 so that the extension arm 126 will not wobble
substantially within the coil spring 128 and so that the extension
arm 126 will extend in a direction which is in axial alignment with
the arm 123. Thus, this slip fit provided between the coil spring
128 and the associated extension arm take the place of other forms
of interconnecting the parts as hereinbefore previously described.
As also hereinbefore previously described, the coil springs 128
permit the outer portion of the sign carried by the extension arms
128 to spill wind from the sign in the event there is a heavy wind
prevailing.
Means is provided for preventing the portions of the sign carried
by the extension arms 126 and 127 from bending beyond a
predetermined angle from the normal when they are spilling wind
from the sign. In FIGS. 12-15, such means takes the form of straps
or strap-like members 131 formed of a suitable material such as
spring steel. The straps 131 are bent generally into a U-shaped
configuration in which one leg portion 131a extends into one end of
the coil spring 128 adjacent one side of the coil spring 128 as
shown particularly in FIG. 15. As also to be noted in FIG. 15,
there is sufficient space between the coil spring 128 and the arms
mounted thereon to accommodate the member 131. One member 131 is
secured to the arm 126 by suitable means such as a rivet 132 and a
spacer 133. Thus, it can be seen that one end of this member 131 is
secured to the arm 126 disposed in one end of the coil spring 128,
whereas the other end of the strap-like member 131 extends into the
coil spring 128 from the end opposite the end which is adjacent the
rivet 132.
In a similar member, the other strap-like member 131 has one
portion 131a disposed in the other end of the spring 128 and has
its other end secured to a rivet 132 and a spacer 133 of the type
hereinbefore described so that the two members 131 are disposed on
opposite sides of the arm 123. In addition, it should be noted that
the strap-like members 131 enter the spring 128 in opposite
directions and are secured by the rivets 132 to the two arms which
extend into the spring 128 as, for example, the arms 123 and
126.
Use of the sign shown in FIGS. 12-15 in conjunction with the
signalling device may now be described as follows. Let it be
assumed that a sign 121 such as that shown in FIGS. 12-15 has been
mounted upon a support stand of the type hereinbefore described.
The sign 121 is provided with a clamp 86 which is adapted to be
secured to a support stand by the use of the clamp 86.
In the event that the sign is placed in a windy location, portions
of the sign carried by the additional extension arms 126 will be
bent rearwardly as soon as the force of the wind overcomes the
yieldable force of the coil springs 128 to thereby permit spilling
of the wind from the sign.
It has been found that with the embodiment shown in FIGS. 1-11 that
there is a tendency for such signs, particularly in strong winds,
to bend so far that it is difficult, if not impossible, for an
oncoming motorist to read the sign. This undesirable feature is
overcome by the straps 131 which are U-shaped and which have the
bottoms of the ends of the coil springs spaced a slight distance
away from the extremities of the associated coil spring so that
limited movement of the outer portion of the sign can occur with
respect to the remaining portions of the sign. Thus, the strap-like
members 131 can be formed to permit the desired angular movement of
the outer extension arms 126 and 127 away from the normal plane for
the sign. This will thus permit spilling of the wind by the sign so
that the sign will not be blown over and which will also limit the
bending so that the sign can be read by motorists or other persons
facing the sign from a distance. The length of the strap-like
members 131 can be chosen so that different angles of bending or
tilting of the extension arms 126 and 127 can be accommodated
before movement is restrained by the strap-like members 131
engaging the ends of the coil spring 128 as shown in broken lines
in FIGS. 12 and 14. The strap-like members 131 will also bend as
the coil spring 128 is being bent, while at the same time limiting
further movement of the extension arm with respect to the arm 122
when the bottoms of the U-shaped portions of the strap-like members
engage the ends of the coil spring 128.
The foregoing construction which is shown in FIGS. 12-15 makes it
possible to construct a sign which will still readily spill wind so
that the sign will not be blown over when it is mounted upon a
support stand and positioned in a strong wind. The strap-like
members 131 which serve to limit the amount of tilting or bending
of the portions of the sign which are spilling the wind thus serve
to ensure that the portions which are spilling the wind remain at
an angle so that it still is readily visible to an oncoming
motorist.
It has been found that even though the tilting of the portions of
the sign which spill the wind is limited to a certain angle, this
does not appreciably affect in any way the ability of the sign to
stand up in very strong winds when it is mounted upon a support
stand. By way of example, it has been found that a sign measuring
48 inches .times. 48 inches mounted upon a support stand and in
which the portions which spill wind from the sign were limited to
an angle of approximately 30.degree. from the normal plane of the
sign, was still able to withstand wind velocities well over 35
miles per hour without tipping over.
It is apparent from the foregoing that there has been provided a
signalling device of greatly improved characteristics particularly
suitable for use in windy locations and which is still readily
visible at all times to an oncoming motorist during windy
conditions. In addition, there is no tendency for the signalling
device to tip over, nor is there a tendency for the sign to turn on
the support stand. The sign cannot rotate because of the
construction of the clamp and also because of the very simple pin
and slot connection provided with the telescoping sections.
* * * * *