Infant length and weight measuring apparatus

A device for measuring the length and weight of an infant. The device includes a tray into which the infant is placed. The tray is located on a scale that is used to determine the infant's weight. A length measuring device is located adjacent the tray and includes a wand that extends into the tray and moves slidably along the length of the tray. An infant is placed within the tray so that the head of the infant is adjacent one end of the tray. The wand then slidably moves toward the infant until it contacts the sole of the infant's foot at which time a length measurement is taken. The length measuring device includes a breakaway switch and a rocker switch that stops the movement of the wand if it contacts the infant or another obstruction. The breakaway switch or rocker switch are triggered when the wand is rotated around an axis of rotation approximately perpendicular to the bottom of the tray or the wand is rotated upwardly from the bottom of the tray around an axis of rotation approximately parallel to the bottom of the tray.

FIELD OF THE INVENTION 
The present invention relates to devices for measuring the length and 
weight of an infant and, more specifically, to measuring devices that 
include safety features to prevent harm to the infant during measurement. 
BACKGROUND OF THE INVENTION 
Infant length and weight statistics are used to assess and monitor infant 
growth and health. Thus, accurate methods and apparatus for measuring the 
length and weight of an infant are necessary for an accurate determination 
of an infant's health. Length and weight measurements are particularly 
important for newborn infants where small changes in length and weight 
affect clinical diagnosis of hypothyroidism, dysmaturity versus 
intrauterine growth failure and proper nutritional planning. 
Infant length and weight measurements are difficult to obtain accurately 
due to the lack of cooperation by most infants. Newborn infants generally 
do not fully extend their legs nor do they like it when an individual 
forces them to extend their legs. In the past, length measurements have 
frequently been taken using a standard ribbon-type tape measure extended 
along the length of the infant. Due to the infant's withdrawn legs, it 
takes one individual to hold the infant and extend at least one leg for 
measurement and a second individual to actually measure the infant's 
length. 
Some prior art length measuring devices place the infant on a platform such 
that the crown of an infant's head is placed adjacent a stop at one end of 
the platform. A slidable guide is then manually moved along the platform 
toward the infant until it contacts the infant's feet. The distance 
between the stop on the platform and the slidable guide is then used to 
determine the infant's length. One such measuring device is described in 
U.S. Pat. No. 4,939,849, issued to Johnson. 
As with other prior art length measuring devices, it is difficult for one 
person to obtain accurate measurements using the Johnson invention due to 
an infant's retracted legs. Unfortunately, infants rarely cooperate and 
stay still with their legs extended in order to allow an operator to 
manually slide the guide into contact with the infant's feet. Thus, as 
with other prior art length measuring devices, the Johnson invention 
requires two people to make accurate measurements, one to hold the infant 
still and extend at least one leg and the other to move the slidable guide 
into contact with the infant's feet. 
Both infant length and weight measurements are required to properly 
diagnose infant growth. Thus, it would be beneficial if a single piece of 
equipment could be used to measure both an infant's weight and length in a 
single operation. It would also be beneficial if a single nurse or doctor 
could take accurate infant length and weight measurements without 
assistance from another person. 
A major concern with all infant measuring and weighing devices is avoiding 
any possible harm to the infant during the measurement process. Infants 
are easily harmed by being pinched or cut or by falling off of equipment 
or furniture if they are left unattended for even a minute. Even newborn 
infants move sufficient amounts to create concern if they are leer 
unattended on a piece of equipment without proper safety restraints. Thus, 
precautions must be taken to ensure that an infant is not harmed during 
length and weight measurements. It is also a concern of doctors and nurses 
that the equipment used to measure an infant's length and weight be simple 
to operate, clean up, and maintain. 
The present invention is a length and weight measuring device that avoids 
some of the above-identified disadvantages of the prior art. 
SUMMARY OF THE INVENTION 
The present invention allows a single operator to easily and accurately 
measure the weight and length of an infant. An operator may place an 
infant within the present invention, hold the infant in the proper 
position and allow the present invention to determine the length and 
weight of the infant without assistance. Thus, the present invention 
eliminates some of the disadvantages of prior length and weight measuring 
devices. In addition, the present invention is easy to operate, easy to 
clean, and is designed to prevent an infant from being harmed during the 
measuring process. In the present invention, the infant is placed on a 
tray that includes four sides or walls that ensure that the infant remains 
on the platform and does not fall off the platform or get harmed in other 
ways. 
One embodiment of the present invention includes a housing on which a 
platform is placed. An infant is placed lengthwise on the platform and is 
located lengthwise along the platform at a predetermined location. An 
actuated wand coupled to the platform moves slidably along the length of 
the platform toward the infant until it contacts the infant. The apparatus 
also includes means for detecting the position of the actuated wand when 
it contacts the infant and for determining the length of the infant as a 
function of the position of the wand when it contacts the infant. 
In accordance with other aspects of the invention, a scale for measuring 
the weight of the infant is provided. The platform includes ends and sides 
adapted to maintain the infant on the platform. The actuated wand is also 
rotatably coupled to the housing and includes control means to stop the 
movement of the actuated wand when the wand rotates about an axis of 
rotation a predetermined amount. In some embodiments, the wand is 
rotatably coupled to the housing about a first axis of rotation 
approximately perpendicular to the platform and a second axis of rotation 
approximately parallel to the platform. 
In other embodiments of the invention, means for producing a signal 
indicative of the location of the wand when it contacts the infant and for 
determining the length of the infant as a function of the signal are 
provided. The movement of the wand toward the infant stops when the wand 
is rotated upon contact with the infant about an axis of rotation either 
normal to the platform or parallel to the platform. The wand is also 
movable between a first position in which it extends at least partially 
across the width of the platform and a retracted position in which it 
extends along the length of the platform. The wand moves between the 
extended and retracted positions when it contacts the infant or another 
obstruction with a predetermined force.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 illustrates a preferred embodiment of a weight and length measuring 
device 10 according to the present invention. The device includes a 
platform or tray 12 sized to accept an infant 13. Tray 12 may be formed of 
any suitable material, such as plastic or metal. In the preferred 
embodiment, tray 12 includes protective ends and sides that maintain the 
infant within the tray. Although an infant should never be left unattended 
in the tray, the tray's protective ends (42, 42) and sides help to 
maintain the infant within the tray and prevent the infant from moving off 
of the tray and thus from being harmed. It is advantageous to form the 
tray from a single piece of a plastic material that can be easily removed 
and cleaned in case the infant defecates or urinates while the length and 
weight are being measured. A single piece tray also avoids sharp edges, 
comers, and holes that could pinch or scratch the infant. 
During operation, the tray containing the infant is placed upon the base 15 
of a scale 14. The scale 14 may be any suitable scale capable of 
accurately measuring the weight of an infant. Scale 14 includes a display 
16 on which the infant's weight is shown and a control panel 18. In the 
preferred embodiment, the scale includes an on-off switch, a gram/pound 
unit selection switch, a zero switch, and a re-weigh switch. In the 
preferred embodiment, the scale zeroes itself upon being turned on, thus 
automatically taking into account differing tray sizes and weights. It is 
also advantageous for the scale to include a zero switch to produce 
accurate infant weight measurements while accounting for articles added to 
the tray during weighing, such as blankets or toys. 
Prior to weighing, the tray 12 and any other articles to be placed within 
the tray during weighing, such as a blanket or toy, are placed on the 
scale and then the zero switch is depressed. The scale 14 then resets the 
scale weight to zero in order to eliminate the effects of the weight of 
the tray and added articles on the measured weight of the infant. After 
zeroing the scale, the infant is placed in the tray and weighed. The 
resulting value is then output to the user on display 16. 
It has been found advantageous for the scale 14 to perform multiple weight 
measurements of the infant, and to then average the measurements to 
determine a final infant weight. The use of the average of multiple weight 
measurements helps to remove measurement errors introduced by any infant 
movement within the tray during weighing. 
In the preferred embodiment shown, a length measuring device 20 is located 
behind the scale 14 and tray 12. The length measuring device could be an 
integral part of the scale 14 or it could be an upgrade added to a 
preexisting scale. Alternately, the length measuring device could be used 
in combination with a tray without the use of a scale at all. 
The length measuring device 20 includes a housing having a wand 22 that is 
rotatably mounted upon a wand housing 24. The wand housing extends 
perpendicularly out from the length measuring device and is slidably 
mounted within a slot 26 in the side of the weight measuring device. The 
slot 26 extends along the length of the upper portion of the length 
measuring device slightly above and approximately parallel to an upper lip 
27 of the tray. The slot allows the wand and wand housing to be driven to 
the left or right within the tray by a carriage assembly 70 (FIGS. 3-4), 
as indicated by arrow 28. 
Wand housing 24 and wand 22 extend outwardly approximately perpendicular to 
the side of the length measuring device and approximately parallel to the 
bottom 29 of the tray past the lip 27 of the tray. The wand 22 then 
extends downwardly into the tray approximately parallel to the rear wall 
31 of the tray part of the way to the bottom 29 of the tray. The wand then 
extends perpendicularly at least partially across the width of the tray. 
This configuration ensures that neither the wand nor wand housing contacts 
the walls of the tray and that the wand extends sufficiently far into the 
interior of the tray to be in proper position to contact the infant as the 
wand moves along the length of the tray. It is important that no part of 
the wand, wand housing, or length measuring device contact the tray during 
normal operation of the length and weight measuring device. This ensures 
that the length measuring device will not interfere with the operation of 
the scale when the weight measurements are being taken. 
During operation, the wand 22 moves to the left, as shown in FIG. 1, toward 
the feet of an infant placed within the tray until it contacts the sole of 
the infant's foot. The infant's length is then calculated as a function of 
the position of the wand when it contacts the infant's foot. The resulting 
length measurement is then output on a display 30. The length measuring 
device 20 also includes a control panel 32, having an on/off button, a 
measure button, a unit of measurement selection button, and a memory 
button. Greater detail of the actual method of operation of the length 
measuring device will be discussed below. 
The internal mechanics of the preferred embodiment of the length measuring 
device 20 will now be described by reference to FIGS. 2-4. As best seen in 
FIG. 2, the top portion 23 of the wand is rotatably attached to the wand 
housing 24 that extends out from the slot 26. Specifically, the top 
portion 23 of the wand is attached to the upper surface 49 of a torsion 
spring 50 that is rotatably mounted within housing 24. 
Torsion spring 50 includes a cylindrical bearing 52 on the top of the 
torsion spring. The cylindrical bearing 52 cooperates with a cylindrical 
opening 53 in the top of the wand housing to allow the torsion spring 50 
and attached wand to rotate clockwise or counterclockwise, as indicated by 
arrow 44 (FIG. 1). Torsion spring 50 biases the wand toward an operating 
position in which the wand extends perpendicularly across the width of the 
tray along the center line 25 of the wand housing (FIG. 2). The torsion 
spring 50 may be any suitable biasing mechanism capable of supplying a 
sufficient biasing force to maintain the wand in its centered position 
during normal operation of the length measuring device. In alternate 
embodiments, torsion spring 50 could be replaced by other biasing means, 
including linear springs. An arm 54 extends perpendicularly out from the 
side of the torsion spring to engage an electrical breakaway switch 56 
when the wand rotates clockwise or counterclockwise. 
As the wand rotates, it rotates the torsion spring 50 and arm 54 in the 
same direction. The wand's, and thus arm's, rotation triggers the 
breakaway switch 56 which opens a circuit, as described in more detail 
below, and causes the wand's movement to stop or returns the wand to a 
"home" position at the right of the tray (FIG. 1). 
If the wand 22 contacts the infant or another obstruction and the breakaway 
switch malfunctions, the wand may continue to move toward the infant or 
obstruction. In this case, the wand may be rotatably displaced clockwise 
or counterclockwise against the biasing force of the torsion spring 50, as 
shown by arrow 44. This rotational movement of the wand allows it to move 
to a retracted position, as shown in phantom in FIG. 1. When the wand is 
in the retracted position, the wand housing and wand may continue to move 
along the length of the tray without extending outwardly into the tray and 
without possibly harming an infant located in the tray. 
The biasing force of the torsion spring 50 is selected to be of a magnitude 
to bias the wand toward the central position illustrated in FIG. 2, but is 
insufficient to prevent the wand from rotating clockwise or 
counterclockwise, as indicated by arrow 44, upon contact with the infant 
or other obstruction. Thus, the biasing force of the torsion spring is 
selected to be of a magnitude to allow the wand to rotate before the force 
exerted by the wand results in harm to either the infant or the length 
measuring device. 
The end of the wand housing 24 opposite the wand is attached to a shaft 60. 
Shaft 60 extends through the slot 26 in the length measuring device (FIG. 
1) and is rotatably mounted in a support arm 62 (FIG. 3). The support arm 
62 is attached to a carriage assembly 70 that moves the wand housing and 
wand along the length of the tray as described below. 
Shaft 60 includes a rocker arm 64 (FIG. 2) that extends perpendicularly out 
from the surface of the shaft over part of the length of the shaft. Rocker 
arm 64 is located on shaft 60 such that it contacts and triggers a rocker 
switch 66 mounted on the side of the support 62 when the wand and wand 
housing are rotated clockwise as shown by arrow 68 in FIG. 2, i.e., when 
the wand is displaced rearwardly by contact with the infant, as shown by 
arrow 46 in FIG. 1. Movement of the rocker arm triggers the rocker switch 
66, which causes the movement of the wand to stop, and a length 
measurement to be determined, as described below. The combination of the 
rotatably mounted shaft 60, rocker arm 64, and rocker switch 66 allows the 
point of contact between the wand and infant's feet to be determined. The 
rocker switch also helps to ensure that the movement of the wand stops 
upon contact with the infant, thus preventing the infant from being 
harmed. 
It may be advantageous to include a biasing means, such as a spring (not 
shown), on the shaft 60. The biasing means would bias the wand housing and 
wand counterclockwise as shown in FIG. 2 so that the wand is maintained 
perpendicular to the plane of the tray until it contacts the sole of the 
infant's foot. The biasing means would help to ensure accurate length 
measurements by helping to eliminate accidental triggering of a length 
measurement upon touching the wand. 
The magnitude of the centering force provided by the torsion spring 50 and 
biasing means on shaft 60 allows the wand to be displaced rearwardly, as 
shown by arrow 46, upon contact with an infant's foot or other obstruction 
prior to the wand rotating clockwise or counterclockwise as shown by arrow 
44. Thus, upon contact with an infant's foot the wand will first be 
displaced rearwardly triggering the rocker switch 66 which triggers a 
length measurement and stops the wand's movement. Only upon contact with 
an unintended obstruction or upon improper operation of the length 
measuring device will the wand be rotatably displaced, as shown by arrow 
44. Both the rocker switch and breakaway switch act as safety measures to 
ensure that movement of the wand stops upon contact with the infant or 
other obstruction. 
As best illustrated in FIGS. 3 and 4, the wand 22, wand housing 24, and 
rocker switch 66 are all mounted on support 62. The support 62 is mounted 
upon a carriage assembly 70 that moves the wand over the length of the 
tray in a manner similar to drive carriages used in dot matrix printers. 
The carriage assembly 70 includes two parallel carriage rods 74 that 
extend along the length of the length measuring device. A carriage housing 
72 is slidably mounted on the carriage rods 74 through the use of two 
cylindrical guides 78 located on opposing sides of the bottom of the 
carriage housing. Guides 78 encircle the carriage rods 74 and allow the 
carriage housing to slide to the left and right as indicated by arrow 79. 
One end of a drive cable 80 is attached to the left side of the carriage 
housing at an anchor point 84. The drive cable extends from anchor point 
84 to the left end of the length measuring device and then passes around a 
rotatably mounted pulley (not shown). The drive cable then extends back to 
the right end of the length measuring device and passes around a drive 
pulley 82. Finally, the opposite end of the drive cable is attached to the 
carriage housing at an anchor point 85 located on the right side of the 
housing. Rotational movement of the drive pulley 82 moves the cable 80 
clockwise or counterclockwise in order to move the carriage housing, and 
thus wand, to the left or right, respectively. 
Drive pulley 82 is connected to a drive mechanism 86 that is in turn 
connected to a central processing unit "CPU" 88 by a conductor 89. In the 
preferred embodiment, the drive mechanism includes circuitry to inform the 
CPU of the location of the carriage housing and the wand as it moves 
either left or right. Rocker switch 66 and breakaway switch 56 are also 
connected to the CPU. 
During operation, the wand and wand housing begin in a home position to the 
extreme right of the tray 12 as shown in FIG. 1. An infant is then placed 
within the tray such that the crown of the infant's head is adjacent the 
left wall 40 of the tray and the body and legs of the infant extend along 
the length of the tray. The operator then holds the infant so that at 
least one leg is fully extended along the length of the tray and the foot 
is slightly pronated so that the sole of the foot is perpendicular to the 
bottom of the tray. The operator then pushes the length measurement button 
on the control panel 32. The carriage assembly then moves the wand to the 
left toward the infant until the wand contacts the sole of the infant's 
foot at which time the wand is displaced rearwardly as shown by arrow 46 
(FIG. 1). 
Displacement of the wand triggers the rocker switch 66 and causes the CPU 
to record the position of the wand when it contacts the sole of the 
infant's feet. Knowing the position of the wall 40, the CPU uses the 
position of the wand when it contacts the infant's foot to determine the 
length of the infant. After contact with the infant's foot, the wand moves 
to the right away from the infant. In the preferred embodiment, it has 
been found advantageous to have the wand move to the right away from the 
infant approximately 2.5 inches and then to take a second and third 
measurement of the infant's length. The CPU can then display all three 
length measurements or average the three length measurements. In the 
preferred embodiment, it has been found most advantageous to display all 
three length measurements. This allows the operator to observe any 
discrepancies in the three length measurements, thus giving an indication 
of whether or not more measurements should be taken. If the three length 
measurements differ substantially, an error occurred during the 
measurement process and the length of the infant should be remeasured. 
After the infant' s length is determined, it is output on display 30 and 
the wand returns to its home position. 
As described above, when the wand contacts the infant or other obstruction, 
the rocker switch 66 is triggered, stopping the wand's movement. If the 
rocker switch should malfunction, continued movement of the wand toward 
the obstruction causes the wand to rotate away from the obstruction (FIG. 
1), triggering the breakaway switch 56 and stopping movement of the wand. 
Even if both the rocker switch and breakaway switch malfunction, the wand 
continues to rotate out of the way of the obstruction to a retracted 
position shown in phantom in FIG. 1. The retracted position allows the 
wand to continue moving along the length of the tray without presenting 
any possible harm to the infant. 
In addition to the safety features described above, the motor 86 is also 
sized so that it will stall when the wand housing or wand contacts the 
infant or another obstruction with a predetermined force. Sizing the motor 
ensures that the wand and wand housing are not driven with sufficient 
force to harm the infant. 
The logical operation of a preferred embodiment of the present invention 
will now be described with reference to the flow chart illustrated in FIG. 
7. After the infant has been placed within the tray, the operator presses 
the measure button on the control panel 32 as shown in block 200. The CPU 
then determines whether or not the wand is at its home position as shown 
in block 202. If the wand is not at its home position, it is moved to its 
home position as shown in block 204. Otherwise, the CPU determines whether 
or not the wand is "true," i.e., whether or not the wand is extended 
perpendicularly across the width of the tray. If the wand is not true, the 
CPU informs the operator to true the wand as shown by block 208. 
If the wand is true, the CPU determines whether or not the device has been 
calibrated as shown in block 210. If the system has not been calibrated, 
the CPU informs the operator to perform the calibration measurement as 
shown in block 212. The device is calibrated by placing a calibration rod 
within the tray so that the rod is in contact with the wall 40 at one end 
and extends perpendicular to the wall 40 along the length of the tray. The 
operator then informs the CPU to perform a calibration algorithm that 
causes the wand to move across the tray until it contacts the calibration 
rod. The CPU then resets its internal calibration to correspond to the 
known length of the calibration rod. 
If the system has already been calibrated, the wand moves forward toward 
the infant's foot as shown in block 214. The CPU then monitors the rocker 
switch 66 and breakaway switch 56 to determine whether or not the wand is 
true, i.e., has not contacted the infant or an obstruction, as shown in 
block 216. As long as neither the rocker switch nor breakaway switch have 
been triggered, the wand continues its movement toward the infant. If 
either the breakaway switch or rocker switch are triggered, the CPU stops 
the movement of the wand and records a length measurement as shown in 
block 218. 
After recording the length measurement, the wand moves backwards 2.5 inches 
as shown in block 220. The CPU then determines whether three length 
measurements have been taken as shown in block 222. If less than three 
length measurements have been taken, the CPU performs the steps of blocks 
214-220 until three length measurements are completed. After three length 
measurements have been completed, the CPU displays the results to the 
operator as shown in block 224. The CPU then turns the unit off as shown 
in block 226. 
A second embodiment of the wand and wand housing is illustrated in FIG. 5. 
Features of the second embodiment not described herein are similar to the 
features described with respect to the first embodiment and may be 
understood by reference to the description of the first embodiment. In the 
second embodiment, the wand housing 324 includes a torsion spring 350 
located at one end. The torsion spring 350 is rotatably connected to the 
wand housing through the use of a suitable fastening device such as a 
screw-type fastener (not shown). The upper surface of the torsion spring 
includes a slot extending across its width into which the wand 320 is 
removably inserted. A rod 352 extends across the slot at one end of the 
torsion spring. 
The wand 320 includes an arm 323 at its uppermost end. The arm 323 includes 
a slot 325 sized to engage and accept the rod 352. The combination of the 
arm 323, slot 325, and rod 352 allows the wand to be releasably coupled to 
the torsion spring and thus wand housing. As shown in phantom in FIG. 5, 
the wand is placed within the slot in the torsion spring such that the 
slot 325 in the arm is placed underneath and engages rod 352. The wand is 
then lowered into place within the slot. 
The wand housing 324 is rotatably attached to a support arm 326 at the end 
opposite the torsion spring. The support arm 326 is in turn attached to 
the carriage housing 328. The end of the wand housing opposite the torsion 
spring also includes a biasing means 329 that biases the wand housing and 
wand into a central position such that the wand remains approximately 
perpendicular to the platform. The biasing means 329 includes a rod 330 
that extends through the wand housing 324. Springs 332 extend between the 
rod 330 and housing 328 on both sides of the rod. The springs 332 bias the 
rod and thus wand housing into its central position. 
As the wand 320 is displaced rearwardly upon contact with an infant, the 
wand and wand housing rotate counterclockwise as shown by arrow 334. This 
rotational movement of the wand housing causes one end of the rod 330 to 
move downwardly as shown by arrow 336 to contact a rocker switch 338. 
Triggering the rocker switch 338 stops the movement of the carriage 
assembly and informs the CPU to take a length measurement in a manner 
similar to that described with respect to the first embodiment. 
The second embodiment does not include a break-away switch coupled to the 
torsion spring. In the second embodiment, the length measuring device is 
simplified by eliminating the break-away switch and depending upon the 
rocker switch 338, break-away, and stalling of the motor driving the 
carriage assembly to ensure that the movement of the wand does not harm 
the infant. 
An alternate embodiment of the wand and wand housing is illustrated in FIG. 
6. Aspects of the alternate embodiment not described below may be 
understood by reference to the detailed description of the first 
embodiment. One goal of the alternate embodiment is to simplify the 
mechanics of the wand housing. In the alternate embodiment, the wand 90 is 
fixedly attached to a flat plate wand housing 92 having a thickness 93. 
Wand housing 92 extends through the slot 94 and is rigidly attached to a 
shaft 96 at the end of the wand housing opposite the wand. Shaft 96 is 
rotatably mounted on a carriage housing 100. 
A torsion spring 104 is mounted on the carriage housing 100 and coupled to 
the shaft 96 such that the torsion spring biases the wand into a centered 
position in which the wand extends partially across the width of the tray 
(not shown). The magnitude of the force supplied by the torsion spring 104 
maintains the wand in position during normal operation and allows the wand 
and wand housing to be rotationally displaced as shown by arrow 106 if the 
wand contacts an unintended obstruction with sufficient force. 
A rocker arm 98 extends outwardly from the surface of the shaft 96 
partially along its length. The rocker arm 98 triggers a rocker switch 108 
when the wand and wand housing are rotationally displaced. Triggering the 
rocker switch 108 causes the wand's movement to stop and the CPU to take a 
length measurement in a manner similar to that described with respect to 
the first embodiment. The alternate embodiment allows the complexity of 
the wand housing and wand assembly to be reduced but decreases the freedom 
of movement of the wand. 
In still other embodiments, the wand could include a touch sensitive switch 
in addition to or instead of the rocker switch and breakaway switch. The 
touch sensitive switch could be placed on the surface of the wand such 
that it is triggered by contact with the infant. In this embodiment, the 
wand could also rotate to increase safety or could be fixedly attached to 
the wand housing. 
While the preferred embodiment of the invention has been illustrated and 
described, it will be appreciated that various changes can be made therein 
without departing from the spirit and scope of the invention.