Automatic injector for hypodermic syringes or the like and lancet holder for use in conjunction with an automatic injector

An apparatus for propelling an elongated device including a sharp object such as a hypodermic syringe and needle or the like into biological tissue, the apparatus including an inner sleeve for carrying the hypodermic syringe or the like and an outer sleeve in which the inner sleeve reciprocates, biasing means being provided for biasing the inner sleeve relative to the outer sleeve. The locking sleeve receives therein the outer sleeve and through at least one recess and ball bearing arrangement, the inner sleeve can be locked relative to the outer sleeve. When the locking sleeve is forced against biological tissue, the ball bearing or bearings release the locked relationship between the inner and outer sleeves and propel the needle of the hypodermic syringe or the like into the biological tissue. An improvement in assembly is provided by the present invention such that the ball bearings can be placed in position without the boring of a ball bearing loading aperture in the locking sleeve. Additionally, a lancet holder is provided which simulates the shape of a syringe. The lancet holder carries a lancet for insertion into the aforedescribed apparatus for utilization in taking of blood samples or the like.

BACKGROUND AND/OR ENVIRONMENT OF THE INVENTION 
1. Field of the Invention 
The present invention relates to apparatuses for propelling elongated 
devices including a sharp object, such a hypodermic syringe and needle or 
the like, into biological tissue, and more particularly to means of 
facilitating the assembly of such an apparatus and means for adapting such 
an apparatus for use in conjunction with a conventional lancet for taking 
of blood samples or the like. 
2. Description of the Contemporary and/or Prior Art 
The psychological as well as physiological trauma associated with the 
injection of therapeutic substances into living bodies by way of the 
needle of a hypodermic syringe or the like and the puncturing of 
biological tissue to take blood samples is well known to anyone 
experiencing or delivering such procedures. Furthermore, for patients 
which must self-inject themselves, such as diabetics who undergo 
continuous insulin therapy, and have only a limited number of sites into 
which insulin can be injected because of the limits of the patient's reach 
during self-injection, the shortcomings of an unadorned conventional 
hypodermic syringe are also well known. For example, it is quite difficult 
for a diabetic to self-inject into the normal injection site on the upper 
portion of the arm because of the inconvenience of reach. Therefore, it 
has long been desirable to provide an apparatus which will aid a diabetic 
in self-injection. 
It is also desirable, especially in injecting children, to camouflage the 
hypodermic syringe so that the presence of the needle thereof is not 
overwhelming. Additionally, pain can be minimized if insertion of a 
hypodermic needle is quick and even, a set of circumstances which are not 
always obtainable under direct human control. Furthermore, since it is 
frequently necessary for family members who are unskilled in injection 
techniques to inject patients, it is quite desirable to have an automatic 
injector which holds a conventional hypodermic syringe and which, upon 
release, quickly causes the needle of the hypodermic syringe to be 
propelled into biological tissue so that therapeutic fluids can be 
injected. 
Prior attempts to produce such automatic devices are known but 
unfortunately these devices have failed, not because of their performance 
when they worked, but because of design flaws which caused malfunctions 
and jamming. Especially in a medical apparatus, reliability and 
repeatability of function is of primary importance and therefore such 
previously known devices have not enjoyed widespread use. 
Illustrative of prior art devices is that disclosed in U.S. Pat. No. 
2,664,086 issued to G. O. Transue on Dec. 29, 1953. Another similar 
apparatus is discussed in the Journal of the American Medical Association, 
Apr. 14, 1956, page 1308, in an article entitled "A New Injector Designed 
to Minimize Pain and Apprehension of Parenteral Therapy" by Figge and 
Gelhause. 
A further prior art apparatus is illustrated in FIGS. 10, 11, and 12 of the 
present application. All of these apparatuses basically include a member 
for holding the syringe and means for shifting the syringe out of a 
housing upon release of the engagement of the syringe holding element and 
the housing. Engagement and temporary locking of the elements of these 
apparatuses has been accomplished by use of ball bearings which engage 
recesses and apertures in the elements of these apparatuses. In some 
instances the ball bearings have been placed in position by deformation of 
the elements and forcing of the ball bearings into position, aided by 
sloppy tolerances of the elements. In other instances, such as the 
apparatus illustrated in FIGS. 10-12 of the present application, insertion 
of the ball bearings have been accomplished through the boring of a ball 
bearing delivery aperture in a selected element. The ball bearings are 
positioned by placement through this aperture and the plugging of the 
aperture after insertion of the ball bearings. This has not proven to be 
satisfactory since the plugged aperture presents a weak spot in the 
assembly and, if the plug either extends too far or not enough in the 
aperture, it can be cause for jamming of the apparatus. While such jamming 
can be rectified, it is not a very pleasant situation if it takes place 
during the process of injection by the apparatus. 
The present invention overcomes the shortcomings associated with the prior 
art by providing a configuration of elements which permits assembly 
without the deformation of any of the elements of the invention or the 
boring of a ball bearing delivery aperture. Therefore, the present 
invention avoids the jamming problems associated with the prior art. 
Another procedure which requires the piercing of a patient's skin by a 
sharp object is in the use of a lancet for piercing a fingertip or other 
site to obtain a drop of blood for blood testing. While such a procedure 
may only be an occasional nuisance for most patients, some patients, such 
as certain diabetics, must test their blood numerous times during the day 
for certain types of therapy. For instance, the diabetics undergoing this 
particular type of therapy may have to pierce their fingertips or other 
sites as many as four times a day. The trauma associated with this process 
is not insignificant and the importance of making a quick and clean 
puncture is magnified. Apparatuses are known in the prior art for forcing 
the point of a lancet into a fingertip or the like by mechanical means. 
For instance, a device is marketed by Ulster Scientific under the trade 
name Autolet. The Autolet apparatus engages a lancet in a spring loaded 
member which is released by pushing of a trigger, this release propelling 
the sharp point of the lancet into a selected tissue site. 
Heretofore, a patient needing to take blood samples and also needing to 
take injections required two separate devices if automated insertion was 
to be accomplished. In contrast, the present invention provides a lancet 
holder which is simulative in shape of a hypodermic syringe so that the 
holder can be used in an automatic injector, such as the type taught by 
the present invention, for automatic insertion of a lancet point into a 
selected tissue site. 
SUMMARY OF THE INVENTION 
Therefore, a primary object of the present invention is to provide an 
apparatus for propelling the needle of a hypodermic syringe or the like 
into biological tissue. 
A further object of the present invention is to provide an apparatus for 
propelling a hypodermic syringe needle into biological tissue quickly and 
with uniform pressure. 
A still further object of the present invention is to provide an automatic 
apparatus for propelling the needle of a hypodermic syringe or the like 
into biological tissue which is not subject to jamming. 
Still another object of the present invention is to provide an apparatus 
for automatically propelling the needle of a hypodermic syringe into 
selected biological tissue wherein the needle of the syringe is hidden 
until after injection. 
Still another further object of the present invention is to provide an 
apparatus for holding a lancet so that it can be used in conjunction with 
an automatic injection apparatus designed for use with a hypodermic 
syringe or the like. 
Another still further object of the present invention is to provide an 
apparatus for propelling the needle of a hypodermic syringe or the like 
into biological tissue which is relatively quick and easy to assemble 
during manufacture and which is capable of an extended trouble free 
lifetime. 
An additional object of the present invention is to provide an apparatus 
for propelling a sharp object such as a hypodermic syringe and needle or 
the like into biological tissue which is simple in design, relatively 
inexpensive to manufacture, rugged in construction, easy to use, and 
efficient in operation. It is also similarly an object of the present 
invention to provide a holder for a lancet for use in conjunction with an 
automatic injector apparatus which embodies these same characteristics. 
These objects, as well as further objects and advantages of the present 
invention, will be readily apparent after reading the ensuing description 
of a nonlimiting illustriative embodiment and viewing the accompanying 
drawing. 
An apparatus for propelling an elongated device including a sharp object, 
such as a hypodermic syringe and needle, or the like into biological 
tissue, according to the principles of the present invention, comprises: 
an inner sleeve forming an open-ended longitudinal chamber therein for 
receiving an elongated device including a sharp object, the inner sleeve 
for removably retaining therein the elongated device, the inner sleeve 
having first and second spaced apart recesses disposed in the outer 
surface thereof, the first recess being of a greater depth than the second 
recess; an outer sleeve forming an open-ended longitudinal chamber therein 
for receiving and for permitting the reciprocation therein of the inner 
sleeve, the outer sleeve having at least one aperture disposed 
therethrough; biasing means for biasing the inner sleeve relative to the 
outer sleeve; ball bearing means dimensioned to reside within the at least 
one aperture and to selectively reside within the second recess when 
aligned with the aperture; and locking sleeve means forming an open-ended 
longitudinal chamber therein for reciprocally receiving therein a portion 
of the outer sleeve adjacent to the at least one aperture disposed 
therein, the locking sleeve providing a raised surface on the inner wall 
of the longitudinal chamber thereof for forcing the ball bearing means 
into the second recess so as to lock the position of the inner sleeve 
relative to the outer sleeve, longitudinal force on the locking sleeve in 
a predetermined direction causing the ball bearing means to disengage the 
raised surface and the inner sleeve to shift position relative to the 
outer sleeve as a result of the action of the biasing means thereon, the 
first recess being provided to accept the ball bearing means during 
assembly of the apparatus, the first recess being of sufficient depth to 
permit the passage of the locking sleeve means over the ball bearing means 
during assembly. 
A lancet holder for use in conjunction with an apparatus for propelling the 
needle of a hypodermic syringe into biological tissue, according to the 
principles of the present invention, comprises: an elongated body portion 
having first and second ends; a head portion disposed at the first end of 
the elongated body portion, the head portion and the body portion 
substantially simulating the shape of a hypodermic syringe; and retaining 
means for retaining a portion of a lancet disposed adjacent to the second 
end of the elongated body portion.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the figures, and more particularly to FIGS. 1 and 2 
thereof, there is illustrated therein an automatic injector apparatus 10. 
The automatic injector apparatus 10 is used to propel a sharpened portion 
of an elongated device into biological tissue or the like. For example, a 
hypodermic syringe and needle can be used in conjunction with the 
automatic injector apparatus 10 to cause the needle thereof to be inserted 
into the skin of a patient so that therapeutic fluid can be delivered by 
the syringe. 
The automatic injector apparatus 10, which accepts a syringe S, is 
assembled from a plurality of components shown in FIG. 2. The hypodermic 
syringe S is received in an inner sleeve 12 as further illustrated in 
FIGS. 3 and 4, such that the barrel of the syringe S is disposed within a 
longitudinal chamber 14 formed by the inner sleeve 12. When the apparatus 
10 is assembled, as hereinafter discussed in conjunction with FIGS. 3 
through 8, a cap 16 forming a longitudinal chamber 18 therein is fixedly 
secured to an end 20 of the inner sleeve 12 such that the longitudinal 
chambers 14 and 18 are coaxial. These components can be press fitted 
together or otherwise joined. 
Disposed about the circumference of the cap 16 is an "O" ring 22 which 
frictionally engages the inner walls of a hollow hexagonal cap cover 24 
such that the cap cover can freely rotate on the "O" ring 22. This is a 
result of the cap cover having an annular recess, not shown, disposed in 
the interior walls thereof to capture a portion of the "O" ring 22. The 
cap cover 24 has disposed therein an elongated substantially rectangular 
opening 26 dimensioned to permit passage therethrough of the flanges F of 
the syringe S when positioned within the apparatus 10. The flanges then 
come to rest in a notch 28 disposed in an end of the cap 16. When the cap 
cover 24 is then rotated relative to the cap 16, the flange F of the 
syringe S is locked between the cap cover 24 and the cap 16, therefore 
precluding unwanted removal or disengagement of the syring S from the 
inner sleeve 12. 
The inner sleeve 12 includes a first recess 30 and a second recess 32 which 
are annular in shape and which are spaced apart along the longitudinal 
axis of the inner sleeve 12. The annular recesses 30 and 32 are of 
different depths, the first annular recess 30 being deeper than the second 
annular recess 32. The first annular recess is provided to facilitate 
assembly of the apparatus 10 while the second annular recess 32 is 
provided to permit locking of the apparatus 10 in a cocked position as 
hereinafter described. 
The apparatus 10 further includes an outer sleeve 34 which forms a 
longitudinal chamber 36 therein. The longitudinal chamber 36 is 
dimensioned to receive and permit the reciprocation therein of the inner 
sleeve 12. The longitudinal chamber 36 is dimensioned so that it is just 
slightly larger than the largest diameter of the inner sleeve 12 presented 
by the ridges 38 and 40 thereof which are disposed, respectively, adjacent 
to the first and second annular recesses 30 and 32. The longitudinal 
chamber 36 has a neck 41 at one end thereof which is reduced in diameter, 
as shown in FIG. 3, to preclude movement of the ridge 38 out of the 
chamber 36 when it is urged toward the neck 41. 
A helical compression spring 42 is provided to bias the inner sleeve 12 
relative to the outer sleeve 34. When the apparatus 10 is assembled, the 
end 44 of the spring 42 rests against a ridge, not illustrated, provided 
within the longitudinal chamber 36 of the outer sleeve 34 and the end 46 
of the helical spring 42 rests against a washer 48 which receives 
therethrough a portion of the inner sleeve 12. The washer 48 in turn rests 
against the ridge 38. As a result, when the inner sleeve 12 is inserted in 
the outer sleeve 34, the spring 42 causes these elements to be urged 
apart. The portion 50 of the outer sleeve 34 is tapered as illustrated to 
facilitate grasping by the user. 
A plurality of radially disposed apertures 52 are disposed through the 
walls of the outer sleeve 34 and are dimensioned so that they can receive 
therein one of a plurality of ball bearings 54. The preferred embodiment 
of the present invention incorporates at least three apertures 52, each 
aperture being equidistantly spaced around the circumference of the outer 
sleeve 34 and for receiving a ball bearing 54 therein. 
Prior to the fitting of the cap 16 on the inner sleeve 12 an "O" ring 56 is 
slipped over the outer surface of the inner sleeve 12 to act as a shock 
absorber when the automatic injector apparatus 10 is released from a 
cocked position, as further shown in FIG. 4. 
The inner sleeve 12 is temporarily locked into a cocked position relative 
to the outer sleeve 34 by the ball bearings 54 residing simultaneously in 
the apertures 52 and the recess 32. The ball bearings are forced into this 
position by a locking sleeve 58 comprising a collar portion 60 and a nose 
portion 62. The collar portion 60 is fixedly secured to the nose portion 
62 when the apparatus 10 is assembled. The collar portion 60 includes an 
annular interior raised surface 64, further illustrated in FIGS. 3 and 4, 
which urges the ball bearings 52 into the annular recess 32 when the inner 
sleeve 12 is shifted longitudinally relative to the outer sleeve 34 such 
that the apertures 52 are aligned with the recess 32. Although the locking 
sleeve 58 is illustrated as being constructed from two separate pieces, it 
is so constructed to facilitate the machining of such elements when 
constructed of metal and, could be fabricated in one piece, if desired, 
depending upon the specific type of material and fabrication technique 
employed. 
The operation of the present invention can be best observed with reference 
to FIGS. 3 and 4. FIG. 3 shows the present invention in a cocked position 
ready for use and FIG. 4 shows the present invention in a released 
position wherein the needle N of the hypodermic syringe S protrudes from 
an opening 64 in the nose portion 62 of the locking sleeve 58. In FIGS. 3 
and 4, the syringe S is inserted within the longitudinal chamber 14 of the 
inner sleeve 12. The syringe S is secured to the inner sleeve 12 by 
insertion of the flanges F thereof within the notch 28 of the cap 16 and 
by the rotation of the cap cover 24 to lock the syringe S in position. In 
the non-cocked or rest position, as shown in FIG. 4, the ball bearings 54 
reside within the apertures 52 and ride on the surface of the inner sleeve 
12 between the spaced apart annular first and second recesses 30 and 32. 
In order to place the apparatus 10 in a cocked position, as illustrated in 
FIG. 3, the user grasps the cap cover 24 in one hand while holding the 
tapered portion 50 of the outer sleeve 34 as the automatic injector 
apparatus 10 is held in a substantially vertical position. By drawing the 
inner sleeve 12, via the cap cover 24, away from the tapered portion 50 of 
the outer sleeve 34, the spring 42 is compressed and the needle N of the 
syringe S is drawn within the locking sleeve 58. Through the effect of 
gravity on the locking sleeve 58, it is urged away from the tapered 
portion 50 of the outer sleeve 34 and, as it falls, the annular raised 
surface 64 causes the ball bearings 54 to be forced inwardly against the 
inner sleeve 12. Therefore, when the inner sleeve is drawn far enough 
relative to the outer sleeve 34 so that the second annular recess 32 is 
aligned with the apertures 52, the ball bearings 54 disposed therein are 
forced into the second annular recess 32 causing locking of the inner 
sleeve 12 relative to the outer sleeve 34. The annular raised surface 64 
has the leading edge thereof beveled to form a ramp to facilitate movement 
of the ball bearings 54 onto the annular raised surface 64. 
When the apparatus 10 is in the cocked position, slight pressure on the 
nose portion 62 of the locking sleeve 58 will cause the annular raised 
surface 64 to leave position over the ball bearings 54 thereby permitting 
the ball bearings to be forced out of the second annular recess 32 
disposed in the inner sleeve 12. When this happens, the inner sleeve 12 is 
no longer locked into position relative to the outer sleeve 34 and the 
inner sleeve 12 is urged by the helical spring 42 so that it thrusts the 
needle N out of the opening 66 in the nose portion 62 of the locking 
sleeve 58. 
When the apparatus 10 is in use, the pressure placed against the nose 
portion 62 would be occasioned by the user gripping the tapered portion 50 
of the outer sleeve 34 and gently pressing the nose portion 62 of the 
locking sleeve 58 against the site into which the needle N is to be 
inserted. This gentle pressure causes movement of the annular raised 
surface 64 within the collar portion 60 of the locking sleeve 58 and 
causes movement of the ball bearings 54 out of the second annular recess 
32 resulting in disengagement of the locking of the inner sleeve 12 and 
the outer sleeve 34. To cushion the end of travel of the relative movement 
of the inner sleeve 12 and the outer sleeve 34, the "O" ring 56 is 
provided as a shock absorber between the end of the tapered surface 50 of 
the outer sleeve 34 and the bottom surface of the cap 16. 
FIGS. 5 through 8 illustrate the manner in which the automatic injector 
apparatus 10 is assembled. During assembly, the washer 48 and the helical 
spring 42 are slipped over the inner sleeve 12 as illustrated in FIG. 5. 
The inner sleeve 12 is then pushed into the longitudinal chamber 36 of the 
outer sleeve 34 until the end 68 of the inner sleeve 12 extends out of the 
end 70 of the outer sleeve 34, as illustrated in FIG. 6, thereby aligning 
the radially disposed apertures 52 with the first annular recess 30. The 
first annular recess 30 is of a depth sufficient to accept the ball 
bearings 54 therein so that they fall below the outer surface of the outer 
sleeve 34 as illustrated in FIG. 6. This permits passage of the collar 
portion 60 over the portion 72 of the outer sleeve 34, which has the 
apertures 52 disposed therein, so that the collar portion 60 can reside in 
the position illustrated in FIG. 7. The cap 16 is then fitted to the 
portion of the inner sleeve 12 adjacent to the end 68 thereof as 
illustrated in FIG. 8. The inner sleeve 12 is dimensioned in conjunction 
with the spacing of the first and second annular recesses 30 and 32 such 
that once the cap 16 is fixedly secured thereto the ball bearings 54 ride 
on the surface of the inner sleeve disposed between the first and second 
annular recesses 30 and 32 but can no longer enter the first recess 30 
which is solely used for assembly purposes. When the end of the inner 
sleeve 12 carrying the cap 16 is drawn back far enough, as hereinbefore 
described, the ball bearings 54 are forced into the second recess 32 by 
the annular raised surface 64 disposed in the interior of the collar 
portion 60 of the locking sleeve 58. As illustrated, the locking sleeve 58 
is shown as being constructed in separate sections, the collar portion 60 
and the nose portion 62, to facilitate machining of these parts but, the 
locking sleeve can be made out of a unitary structure if desired. 
It therefore should be understood that the first annular recess 30 presents 
structure for temporarily permitting the ball bearings 54 to recede into 
the inner sleeve 12 a sufficient distance so that the ball bearings 54 do 
not protrude out of the apertures 54 thereby permitting the collar portion 
60, which has an inner diameter just slightly larger than the outer 
diameter of the outer sleeve 34, to slide over the apertures 52, having 
the ball bearings 54 disposed therein. Once the inner sleeve 12 is drawn 
further back and the cap 16 is affixed thereto, the ball bearings can no 
longer fall into the first recess 30 and they are securely positioned 
without necessitating the deformation of any of the parts of the present 
invention or the provision of a ball bearing loading hole as has been 
provided in some prior art devices. 
An apparatus typical of prior art devices which include ball bearing 
loading apertures is illustrated in FIGS. 10 through 12. The prior art 
apparatus 80 includes an inner sleeve 82, an outer sleeve 84, and a 
locking sleeve 86. An aperture 88 is disposed in the outer sleeve 84 and 
is provided to capture therein a ball bearing 90. This prior art apparatus 
is assembled by placing the inner sleeve 82 thereof in the outer sleeve 84 
thereof and then placing the locking sleeve 86 in position over the outer 
sleeve 84. As further illustrated in FIGS. 11 and 12, the outer sleeve 84 
has a ball bearing loading aperture 92 disposed therein. A ball bearing is 
dropped into the aperture 88 through the ball bearing loading aperture 92 
after alignment of the apertures 88 and 92. After this ball bearing is in 
position, the locking sleeve must be rotated until the ball bearing 
loading aperture 92 is aligned with another aperture 88 and this process 
is continued until all the ball bearings 90 are in position. 
After all the ball bearings are in position in the apertures 88, the ball 
bearing loading aperture 92 is plugged with a plug 94 which preclude the 
ball bearings 90 from falling out. The plug 94 must be precisely placed 
because if it is too long it will cause the ball bearings 90 to hang up 
jamming the apparatus and if it is too short not only can jamming occur 
but accidental release, a very poor shortcoming, can also possibly occur. 
In contrast to the previously described prior art apparatus, the present 
invention totally eliminates the need for a ball bearing loading aperture 
and a plug, therefore avoiding the shortcomings of the prior art and 
providing for a faster and easier assembly procedure. The use of a second 
annular recess in the inner sleeve of an automatic injector is not shown 
or suggested anywhere in the prior art and heretofore loading of ball 
bearings was either accomplished, as previously mentioned, by the use of a 
ball bearing loading aperture or the deformation of the parts of an 
injector to accommodate the forcing of a ball bearing in position, a 
condition which dictates sloppy tolerances and therefore a marginally 
effective apparatus. 
With reference to FIG. 9, there is illustrated therein a lancet holder 100. 
Lancet holder 100 comprises an elongated body portion 102 and a head 
portion 104. The head portion 104 includes flanges 106, the head portion 
104 and the body portion 102 substantially simulating the shape of a 
hypodermic syringe. The head portion 104 further includes a recess 108 
disposed therein to facilitate the gripping thereof by the user. The end 
110 of the elongated body portion 102 has a recess 112 dimensioned for 
receiving therein the body of a lancet L having a sharpened needle N. The 
lancet L is of a conventional design and typically comprises a cylindrical 
plastic body into which is embedded a longitudinal steel rod having a 
sharpened end forming the needle N. The recess 112 is dimensioned to 
receive and removably frictionally retain therein the cylindrical body of 
the lancet L. When the lancet L is so inserted, the lancet holder 110 and 
lancet L effectively have the same shape as a hypodermic syringe and 
needle. Therefore, the holder can be loaded into the aforedescribed 
automatic injector apparatus or any similar apparatus designed for 
automatic injection of a hypodermic syringe needle. As a result, the 
lancet L, which is commonly used to make small openings in tissue for 
blood samples, can be propelled into tissue with the same speed, accuracy, 
and constant pressure which is provided when such an automatic injector 
apparatus is employed to inject or propel a needle into biological tissue. 
Therefore, through use of the lancet holder 100, an apparatus which has 
previously only been able to be used with hypodermic syringes can now also 
be used with lancets thereby obviating the need for purchasing a separate 
injector for use with the lancets. Although one retention means for the 
lancet is illustrated in the form of a recess 112, it is to be understood 
that any suitable means for grasping of the lancet by the holder can be 
employed and clamps or the like or frictional engagement means other than 
illustrated can be employed, as are well known by those of ordinary skill 
in the art, within the principles and scope of the invention. 
Most of the components of the automatic injector apparatus and the lancet 
holder have been machined from aluminum in models of the present invention 
which have been constructed. However, it is recognized that various other 
materials including plastics can be used to construct the various pieces 
of the present invention. 
Furthermore, it will be understood that various changes in the details, 
materials, arrangements of parts and operational conditions which have 
been herein described and illustrated in order to explain the nature of 
the invention may be made by those of ordinary skill in the art within the 
principles and scope of the invention.