U.S. patent number 3,791,779 [Application Number 05/276,563] was granted by the patent office on 1974-02-12 for pump rotor adjustment mechanism.
This patent grant is currently assigned to Dover Corporation. Invention is credited to Richard E. Nelson.
United States Patent |
3,791,779 |
Nelson |
February 12, 1974 |
PUMP ROTOR ADJUSTMENT MECHANISM
Abstract
A rotary pump having a housing defining therein a pump chamber
and a rotor disposed within said pump chamber for pumping fluid
between inlet and outlet ports. The rotor includes slidable vanes
which slidably engage an internal guide surface formed on a
ringlike cylinder. The ringlike cylinder is fixedly connected to a
pair of head members which define opposite ends of the pump chamber
and rotatably support the rotor shaft. A plurality of eccentric
pins are fixedly connected between each head member and the
adjacent axial end of the cylinder for permitting the cylinder,
when the pump is being assembled, to be selectively positioned in
one of at least two predetermined positions relative to the head
members to permit the minimum clearance between the rotor and the
inner guide surface to be selected in accordance with the type of
fluid to be pumped.
Inventors: |
Nelson; Richard E. (Grand
Rapids, MI) |
Assignee: |
Dover Corporation (Grand
Rapids, MI)
|
Family
ID: |
23057137 |
Appl.
No.: |
05/276,563 |
Filed: |
July 31, 1972 |
Current U.S.
Class: |
418/30; 418/39;
418/107 |
Current CPC
Class: |
F01C
21/102 (20130101); F04C 2/3441 (20130101); F04C
2230/603 (20130101) |
Current International
Class: |
F01C
21/10 (20060101); F01C 21/00 (20060101); F04C
2/344 (20060101); F04C 2/00 (20060101); F01c
021/16 () |
Field of
Search: |
;418/30,39,107 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Husar; C. J.
Assistant Examiner: Smith; Leonard
Attorney, Agent or Firm: Woodhams, Blanchard & Flynn
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. In a rotary pump of the fixed-clearance type, including housing
means having a pair of spaced head plates and a ringlike cylinder
disposed between and fixedly connected to said head plates, said
cylinder having an inner annular guide surface, said cylinder and
said head plates defining a pumping chamber therebetween, a
rotatable pumping rotor disposed within said chamber and mounted
for rotation about an axis which is fixed relative to said head
plates, said rotor having a plurality of vanes thereon disposed for
slidable engagement with an inner annular guide surface formed on
said cylinder, and means defining inlet and outlet openings
communicating with said pumping chamber, the improvement
comprising:
connecting means coacting between said cylinder and said head
plates for permitting said cylinder to be positioned in a selected
one of two predetermined positions relative to said head plates
only during assembly of said pump housing means, the preselection
of one of said two positions during assembly of the pump housing
enabling the pump to be provided with a preselected one of two
different minimum clearances between the rotor and the surrounding
cylinder;
said connecting means comprising eccentric pin means coacting
between each of said head plates and said cylinder for fixedly
connecting and positioning said cylinder relative to said head
plates in a selected one of said two predetermined positions, said
eccentric pin means including at least two eccentric pin members
fixedly connected between each said head plate and an adjacent
axial end of said cylinder;
each said eccentric pin member including first and second
cylindrical portions axially spaced but fixedly connected together,
said first and second cylindrical portions respectively having
first and second longitudinally extending axes which are
substantially parallel but laterally spaced from one another by a
predetermined distance;
at least one axial end face of said eccentric pin members being
provided with indicia means thereon for indicating the orientation
of said eccentric pin members relative to the longitudinally
extending axis thereof, said indicia means permitting selective
orientation of said pin members relative to said cylinder during
assembly of said pump so as to permit said cylinder to be fixed
relative to said head plates in a selected one of said two
predetermined positions to permit preselection of the minimum
clearance between the cylinder and the pump rotor;
each said head plate having at least two cylindrical recesses
formed therein for snugly receiving therein one of the cylindrical
portions of said eccentric pin members, and each axial end of said
cylinder also having at least two cylindrical recesses formed
therein for snugly receiving therein the other cylindrical portions
of said eccentric pin members, the cylindrical portions of the
eccentric pin members being press-fitted into their respective
cylindrical recesses as formed in said head plates and said
cylinder for fixedly and rigidly connecting together said head
plates, said cylinder and said eccentric pins, thereby providing
said assembled pump with a non-adjustable fixed minimum
clearance.
2. A pump according to claim 1, wherein the first and second axes
of said eccentric pin member are laterally spaced from one another
by a distance in the range between 0.001 and 0.060 of an inch.
Description
FIELD OF THE INVENTION
This invention relates to a rotary pump and, in particular, to an
improved rotary pump having eccentric means coacting between the
cylinders and the pump head members, which eccentric means can be
selectively positioned during assembly of the pump to permit a
preselection of the minimum rotor clearance.
BACKGROUND OF THE INVENTION
Rotary pumps are extensively utilized for pumping both low
viscosity and high viscosity fluids. While rotary pumps are
satisfactory for pumping these different types of fluids,
nevertheless successful utilization of rotary pumps requires that
the minimum rotor clearance be varied in accordance with the
viscosity of the fluid being pumped. For example, the minimum
clearance between the rotor and the surrounding guide surface as
formed on the liner or cylinder must be substantially greater when
pumping a highly viscous fluid than when pumping a fluid of low
viscosity.
To permit rotary pumps to be readily adapted to the different types
of fluids, it has been conventional to utilize two different types
of rotary pumps. The first type of rotary pump in common usage
provides a fixed rotor clearance, whereupon after assembly of the
pump the rotor clearance cannot be varied. Pumps of this type are
highly desirable since the structure and mechanical complexity are
maintained at a minimum, so that the pumps thus have a minimum size
and weight, and can be manufactured and assembled relatively
economically and efficiently. However, the known rotary pumps
having a fixed rotor clearance are not readily adaptable for use
with different types of fluids due to the variation required in the
rotor clearance in order to permit use with fluids of different
viscosity.
To overcome the problems caused by the use of different fluids in a
fixed clearance pump, it is a conventional manufacturing practice
to provide a common housing structure for the pump, with the common
housing being usable with a plurality of rotors having different
diameters. The rotor diameter is then selected in accordance with
the type of fluid to be pumped, whereby the rotor clearance is thus
determined during assembly of the pump solely by selecting a rotor
of the desired diameter. While this manufacturing technique is
satisfactory, nevertheless it increases the overall cost of the
pump since the manufacturer has to manufacture and stock several
different rotor diameters. This necessarily increases the
manufacturing cost and also increases the amount of inventory which
the manufacturer must maintain in his plant. This also makes
replacement of the rotor a more difficult task since the user of
the pump must be sure to replace the old rotor with a new rotor of
the proper diameter. Also, after the pump has been assembled, the
rotor is totally enclosed within the pump housing and thus it is
difficult to determine whether the pump parts are properly
aligned.
Another technique which has been widely used to permit rotary pumps
to be usable with fluids having widely different viscosities
involves the use of rotary pumps having adjustment structures
associated therewith for varying either the position, of the rotor
or the position of the surrounding casing. These adjustable pumps
have employed numerous techniques for performing this adjustment.
For example, various pumps of this type have utilized rotatable
eccentric cams coacting with slots formed in the casing for
permitting the position of the casing to be varied relative to the
rotor. These adjustment operations can often be carried out at any
time after the pump has been assembled so as to provide the desired
rotor clearance. Other adjustable pumps of this type have utilized
a casing constructed of a plurality of pivotally connected links
which are deformed by suitable adjustment structure into the
desired configuration. However, these adjustable pumps are not as
desirable as fixed-clearance pumps since they are structurally and
mechanically complex, and result in the pump being bulky and heavy.
Also, the structural and mechanical complexity of these adjustable
pumps makes them extremely costly to manufacture and assemble, and
more difficult to repair and maintain. The adjustment structure
also substantially complicates the sealing of the pump.
Accordingly, pumps of this type have found wide usage only in those
situations where fluids of widely varying viscosities are being
pumped through the same pump during various operational periods
thereof so that the pump must be capable of adjustment wwithout
being disassembled. However, in situations where the pump is used
for substantially continuous operation with fluids of similar
viscosity, a fixed-clearance pump is more economical and
desirable.
Accordingly, it is an object of the present invention to provide an
improved rotary pump which overcomes the above-mentioned
disadvantages. Particularly, it is an object of the present
invention to provide:
1. An improved rotary pump of the fixed-clearance type which can be
selectively assembled to provide at least two different rotor
clearances in order to permit same to have a clearance selected in
accordance with the type of fluid which is to be pumped
therethrough.
2. A pump, as aforesaid, which includes the same identical
structure irrespective of which rotor clearance is provided
therein.
3. A pump, as aforesaid, which utilizes the same rotor and
surrounding cylinder irrespective of the rotor clearance
selected.
4. A pump, as aforesaid, which includes eccentric connecting
structure coacting between the cylinder and the housing head
members for permitting the cylinder to be stationarily mounted in
at least two different positions relative to the rotor whereby the
rotor clearance can be a selected one of two predetermined
magnitudes merely by varying the position of the eccentric
connecting structure during assembly of the pump.
5. A pump, as aforesaid, which includes eccentric pins coacting
between stationary housing parts and the cylinder, which pins can
be selectively connected between the cylinder and the stationary
housing parts in two different angular orientations to vary the
cylinder position relative to the rotor.
6. A pump, as aforesaid, wherein the eccentric pins, after being
positioned in a selective orientation to provide either a small or
a large rotor clearance, are snugly fitted within openings in the
cylinder and the stationary housing parts to provide a fixed
clearance.
7. A pump, as aforesaid, which permits the tolerances of the pump
components to be more closely maintained, which permits more
economical manufacturing of the components, and which simplifies
and facilitates the assembly and alignment of the pump.
Other objects and purposes of the present invention will be
apparent to persons acquainted with devices of this type upon
reading the following specification and inspecting the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view, partially in section, illustrating a
rotary pump according to the present invention.
FIG. 2 is a sectional, elevational view taken substantially along
the line II--II in FIG. 1.
FIG. 3 is an enlarged, fragmentary, sectional view taken
substantially along the line III--III of FIG. 2, and illustrating
therein the two positions of the cylinder relative to the
rotor.
FIG. 4 is a side view of the eccentric connecting pin constructed
according to the present invention.
FIG. 5 is an end view of the eccentric pin as taken from the left
side of FIG. 4.
FIG. 6 is an end view of the eccentric pin as taken from the right
side of FIG. 4.
Certain terminology will be used in the following description for
convenience in reference only and will not be limiting. For
example, the words "upwardly," "downwardly," "leftwardly" and
"rightwardly" will refer to directions in the drawings to which
reference is made. The words "inwardly" and "outwardly" will refer
to directions toward and away from, respectively, the geometric
center of the pump and designated parts thereof. Said terminology
will include the words above specifically mentioned, derivatives
thereof and words of similar import.
SUMMARY OF THE INVENTION
In general, the objects and purposes of the present invention are
met by providing a rotary pump having housing means defining a
pumping chamber and, by way of example, a vaned rotor positioned
within the chamber. The housing means includes a ringlike cylinder
having an inner annular guide surface disposed in surrounding
relationship to the rotor, which guide surface is eccentrically
positioned relative to the rotational axis of the rotor. The
cylinder is fixedly connected between a pair of stationary head
members which are disposed on opposite sides of the pumping
chamber, which head members rotatably support the rotor shaft. The
cylinder is fixedly connected to each head member by a plurality of
screws and eccentric pins. During assembly of the pump, the pins
can be oriented in at least two different positions relative to the
head members for enabling the cylinder to be positioned between the
head members in a selected one of two different predetermined
positions. The position of the cylinder as determined by the
eccentric pins determines the magnitude of the minimum clearance
between the rotor and the inner guide surface, whereby the minimum
rotor clearance can thus be selected from two different magnitudes
depending upon the preselection of the position of the eccentric
pins relative to the head members upon assembly of the pump. The
eccentric pins each include a pair of axially spaced, cylindrical
portions which are eccentrically positioned relative to one
another. The axially spaced cylindrical portions of each eccentric
pin are adapted to be snugly fitted, as by being press-fitted,
within cylindrical recesses formed in the cylinder and the head
members, respectively. When the eccentric pins are installed in the
position providing for a small minimum rotor clearance, then the
pump is usable with nonviscous or low viscosity fluids, whereas
when the eccentric pins are installed to provide a larger minimum
rotor clearance, then the pump is usable with high viscosity fluids
or where the shear properties of the fluids become significant. The
pins are preferably provided with visible indicia thereon to
readily indicate the selected rotor clearance.
DETAILED DESCRIPTION
FIGS. 1-3 illustrate a rotary pump 11 having a housing 12 which
supports a rotatable shaft 13. A pump rotor 14 is nonrotatably
secured to the shaft 13 and is positioned within a pump chamber 16
formed within the housing 12.
The pump housing 12 includes a pair of opposing head members 17 and
18 which have integral head plates 19 and 21, respectively,
disposed in spaced but opposed relationship to one another. A
ringlike casing or cylinder 22 is positioned between the head
plates 19 and 21 and is fixedly connected thereto, as by a
plurality of screws 23. The cylinder 22 has an inner annular guide
surface 24 which is disposed in eccentric relationship relative to
the rotational axis 26 of the shaft 13. The configuration of the
inner guide surface 24 may either be circular or non-circular
depending upon the type of pumping profile desired, and the exact
configuration of the surface 24 does not constitute an essential
portion of the present invention.
The cylinder 22 also has a pair of annular wear plates 27 and 28
mounted thereon adjacent the opposite axial ends thereof. The wear
plates 27 and 28 are disposed directly adjacent the head plates 19
and 21, respectively, and define the opposite ends or boundaries of
the pumping chamber 16. The wear plates 27 and 28 are positioned to
slidably but sealingly bear substantially against the opposite
axial ends of the pumping rotor 14 in a conventional manner.
Considering now the pumping rotor 14, same includes a substantially
cylindrical member 31 nonrotatably secured to the shaft 13 and
positioned within the pumping chamber 16. The member 31 has the
opposite axial ends thereof positioned closely adjacent and in
substantial rotatable sliding engagement with the wear plates 27
and 28. Cylindrical member 31 has a plurality of angularly spaced,
radially extending slots 32 formed therein. A vane 33 is slidably
supported within each slot 32 and is resiliently urged outwardly of
the member 31 by means, such as the push rods 34, whereupon the tip
or outer end of each vane is disposed in slidable engagement with
the inner guide surface 24.
The drive shaft 13 for the rotor 14 is rotatably supported on a
pair of spaced bearings 36 and 37 which are mounted on the head
members 17 and 18, respectively. The outer end of the head member
18 is also sealingly closed by means of an end cap 38. The other
end of the drive shaft 13 extends outwardly beyond the head member
17 and is adapted to be connected to a suitable power source, such
as a motor. The shaft 13 is sealed relative to the head member 17
by conventional means such as the packing gland 39 and conventional
seal rings 41.
Fluid is supplied to the pumping chamber 16 through inlet and
outlet conduits 42 and 43, respectively, which conduits in the
illustrated embodiment are fixedly connected to the opposite sides
of the cylinder 22. The conduits 42 and 43, respectively, include
therein inlet and outlet flow openings 44 and 46. Suitable mounting
flanges 47 and 48 may be provided on the free ends of the conduits
42 and 43, respectively, for permitting same to be suitably
connected to associated pipes or conduits (not shown).
The structure of the rotary pump 11, as described above, is
substantially conventional and thus further description thereof is
not believed necessary. Further, it will be apparent to persons
acquainted with pumps of this type that numerous variations can be
made in same without departing from the essence of the present
invention. For example, while the attached drawings illustrate the
guide surface 24 as being formed directly on the interior of the
cylinder 22, it will be appreciated that in many situations rotary
pumps utilize a separate annular lining which is constructed of a
specific material or configuration in order to provide a desired
flow pattern or wear characteristic, which separate lining is then
pressed or fixedly fitted within the casing or cylinder. Such a
modification could also be incorporated into the rotary pump of the
present invention. Further, the location of the inlet and outlet
passages and their relationship to the housing and the rotor can
likewise be varied while still resulting in an operable pump
structure.
Considering now the rotary pump 11 incorporating therein the
present invention, same includes suitable positioning means
coacting between the head members 17 and 18 and the intermediate
cylinder 22 for permitting the cylinder 22 to be disposed in at
least two alternate positions relative to the rotor 14 when the
pump is being assembled. In this manner, the pump can be assembled
to have a minimum clearance between the rotor and the cylinder for
use with less viscous fluids, or alternately the cylinder can be
assembled to provide for increased clearance between the cylinder
and the rotor to permit utilization of same with highly viscous
fluids. However, after the pump is assembled, then the cylinder is
maintained stationary relative to the housing so that the clearance
between the rotor and the cylinder is thus maintained at a fixed
value.
The positioning means of the present invention specifically
includes a plurality of eccentric pin means 51 and 52 coacting
between the head plates 19 and 21, respectively, and the cylinder
22 for positioning the cylinder 22 relative to the rotor. In the
disclosed embodiment, cylinder 22 is connected to head plate 19 by
a pair of eccentric pin means 51 which are disposed on
diametrically opposite sides of the cylinder 22, and is connected
to the head plate 21 by a pair of eccentric pin means 52 which are
also disposed on opposite diametrical sides of the cylinder 22.
However, the number of angularly spaced eccentric pin means 51 and
52 can be selectively varied if desired.
The eccentric pin means 51 and 52 are identical and, as illustrated
in FIGS. 4-6, each includes a large diameter cylindrical portion 53
having a central axis 54 and fixedly connected to a small diameter
cylindrical portion 56 having a central axis 57. The central axes
54 and 57 are parallel with one another but are laterally offset by
a predetermined distance e as illustrated in FIG. 4, which distance
e may vary between 0.001 and 0.060 of an inch for the type of pump
illustrated herein. However, this range might be extended
materially where a modified pump is involved. The offset or
eccentricity e of the small cylindrical portion 56 relative to the
large cylindrical portion 53 is utilized according to the present
invention to permit the initial position of the cylinder 22 to be
varied relative to the head plates 19 and 21.
The large cylindrical portion 53 is preferably provided with an
arrow 59 imprinted on the axial end face 58 thereof, and the small
cylindrical portion 56 is similarly provided with an arrow 62
imprinted on the axial end face 61 thereof. The arrows 59 and 62
are parallel and point in the same direction, and are similarly
parallel to a plane containing therein the axes 54 and 57. The
arrows 59 and 62 thus point in a direction which represents the
maximum distance e between the axes 54 and 57. The large
cylindrical portion 53 may also be provided with a pair of opposed
flats 63 for example, to permit same to be engaged and rotated by a
suitable tool.
The large diameter portion 53 of each pin means 51 is snugly
received within a cylindrical bore or recess 66 formed in the head
plate 19, and the small diameter portion 56 is similarly snugly
received within a cylindrical bore 67 formed in the adjacent axial
end of the cylinder 22. The eccentric pin means 52 is similarly
mounted in that the large diameter portion 53 is snugly received
within a cylindrical recess 68 formed in the head plate 21, and the
small diameter portion 56 is snugly received within a cylindrical
recess 69 formed in the adjacent axial end of the cylinder 22. The
relative positions of the large and small ends of the pins may be
reversed, if desired. The recesses 67 and 69, as formed on the
opposite axial ends of the cylinder 22, are substantially axially
aligned with one another in the preferred embodiment.
The eccentric pins 51 and 52, when assembled within the rotary pump
11 such that the arrows point upwardly, result in the cylinder 22
being positioned in its lowermost position relative to the axis 26
of the shaft 13, whereby the minimum clearance between the rotor 14
and the surrounding guide surface 24 is of a first predetermined
magnitude, which minimum clearance is designated 71 of the left
side of FIG. 3. On the other hand, when the eccentric pin means 51
and 52 are assembled within the rotary pump with their arrows
pointing downwardly (as illustrated on the right side of FIG. 3),
then the cylinder 22 is disposed in its uppermost position relative
to the axis 26 of the shaft 13, so that the minimum clearance
between the rotor 14 and the guide surface 24 is a second
predetermined value, which minimum clearance is designated 71' in
FIG. 3. The minimum clearance 71' is greater than the minimum
clearance 71. Thus, by selectively assembling the cylinder relative
to the head plates through use of eccentric pins 51 and 52 which
are alternately positionable in two positions which are angularly
displaced from one another by an angle of 180.degree., the cylinder
22 can be disposed relative to the rotor 14 to thus provide for a
minimum rotor clearance having two different predetermined
values.
Further, bolt holes 73 as formed in the head plates 19 and 21 are
slightly larger than the diameter of the screws 23 to permit the
cylinder 22 to be selectively disposed in either of the
above-mentioned positions when the pump is assembled.
ASSEMBLY AND OPERATION
The operation of the rotary pump 11 constructed according to the
present invention is conventional, and thus a detailed description
thereof is not believed necessary. However, inasmuch as rotary
pumps of this type are often utilized with fluids having a wide
range of viscosity, the pump 11 of the present invention
incorporates therein the eccentric pin means 51 and 52 which permit
the pump to be most efficiently utilized with either a low
viscosity or a high viscosity fluid.
If the pump 11 is to be utilized with a low viscosity fluid, then
the pump is assembled with the eccentric pin 51 and 52 disposed so
that the arrows 59 and 62 point upwardly. This thus results in the
cylinder 22 being disposed in its uppermost position relative to
the axis 26 of the shaft 13, thereby resulting in the rotor
clearance 71 having its smallest possible magnitude. This assembly
of the pump is illustrated in the left side of FIG. 3. Since the
minimum clearance 71 is at its smallest value, this thus results in
the pump 11 being most efficiently utilized for pumping low
viscosity fluids.
On the other hand, if the pump is to be utilized for pumping highly
viscous fluids, then the eccentric pins 51 and 52 are initially
rotated during assembly of the pump so that the arrows 59 and 62
point downwardly. This results in the cylinder 22 being disposed in
its uppermost position so that the rotor clearance 71' is of a
larger predetermined magnitude, substantially as illustrated on the
right side of FIG. 3. Since the minimum rotor clearance 71' is
larger than the rotor clearance 71, the pump is thus most
efficiently utilized for highly viscous fluids, such as syrups and
the like.
After the pump has been assembled, the arrows 59 formed on the
eccentric pin means 52 are readily visible since the cylindrical
bores 68 extend through the head plate 21. Accordingly, a person
can readily visually determine from the vertical direction of the
arrows whether the pump is assembled for use with low viscosity or
high viscosity fluids. Even though the large diameter portions of
the eccentric pins may be totally disposed within the recesses
formed in the head plates, they may be externally accessible.
Accordingly, if the pins are rotatable, they can be rotated through
an angle of 180.degree. after the pump has been assembled, provided
that the screws fastening the head plates to the cylinder are first
loosened.
The pump of the present invention thus incorporates therein the
structural and mechanical simplicity of a fixed clearance pump,
while at the same time it permits the fixed minimum clearance to be
initially selected between two different magnitudes in an easy and
simple manner in order to permit the same basic pump structure to
be utilized with fluids having substantially different viscosities.
In this manner, the manufacturer no longer has to utilize or stock
two different rotor sizes to permit the same pump housing to be
used for both viscous and nonviscous fluids. Rather, the
manufacturer can now utilize the same pump housing and the same
rotor for either viscous or nonviscous fluids, with the only
modification being in the orientation of the eccentric pin means 51
and 52 during assembly of the pump in accordance with the type of
fluid with which the pump is to be utilized.
Utilization of the eccentric pin means 51 and 52, and the manner in
which they coact with the cylinder 22 and the head plates 19 and
21, also results in other significant manufacturing advantages
which permit the overall pump structure to be manufactured more
economically and efficiently while still resulting in a pump having
closer tolerances. For example, one axial end of the cylinder 22 is
initially bored so as to have the pair of recesses 67 or 69 formed
therein. Thereafter, all turning and drilling operations which have
to be performed on the cylinder 22 can then be keyed to these two
holes. Because of this design feature and procedure, tolerances of
the cylinder can be held much closer than was previously possible.
These same holes can then be utilized to permit precise location of
the coacting openings and recesses which are to be formed in the
head plates, whereby he overall assembly can thus be machined
economically and with extremely close tolerances, thereby providing
for extremely accurate clearances between the rotor and its
surrounding guide surface. This thus results in more accurate
clearances between the rotor and the guide surface and also
minimizes the alignment problems associated with the assembly of
the pump.
Although a particular preferred embodiment of the invention has
been disclosed in detail for illustrative purposes, it will be
recognized that variations or modifications of the disclosed
apparatus, including the rearrangement of parts, lie within the
scope of the present invention.
* * * * *