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Title:
A MACHINE FOR PERFORMING MICROFINISHING OPERATION ON A COMPONENT
Document Type and Number:
WIPO Patent Application WO/2019/012509
Kind Code:
A1
Abstract:
The present disclosure envisages a machine (200) for performing microfinishing operation on a component. The machine (200) comprises a rotatable shaft (235), means for rotating the rotatable shaft, a first set of plates (110) slidably mounted on shaft (235), arms fitted on the first set of plates (110) in a one-to-one correspondence, fixtures provided at free end of the 5 arms for replaceably receiving microfinishing tools, and a spacing mechanism (100) for varying the distance between the plates (110) of the first set in a controlled manner for performing microfinishing operation. The spacing mechanism (100) comprises a second set of plates (115) angularly displaceable by the shaft (235) to vary distances between adjacent arms and thereby between tools attached to the arms in an operative configuration for performing a microfinishing operation on the component. The mechanism (100) is time- effective, cost-effective and reliable.

Inventors:
KELKAR, Sameer (H. No. 5-9-105, Pagariya Colony Station Roa, Aurangabad Maharashtra 5, 431005, IN)
Application Number:
IB2018/055224
Publication Date:
January 17, 2019
Filing Date:
July 14, 2018
Export Citation:
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Assignee:
KELKAR, Sameer (H. No. 5-9-105, Pagariya Colony Station Roa, Aurangabad Maharashtra 5, 431005, IN)
International Classes:
B24B5/42; B24B5/04; B24B5/12; B24B33/04
Foreign References:
US3126672A1964-03-31
US20140299345A12014-10-09
Attorney, Agent or Firm:
DEWAN, Mohan (R. K. Dewan & Co. Podar Chambers, S. A.Brelvi Road, For, Mumbai Maharashtra 1, 400001, IN)
Download PDF:
Claims:
CLAIMS:

1. A machine (200) for performing microfinishing operation on a component, said machine (200) comprising:

• a rotatable shaft (235);

• means for rotating the rotatable shaft (235);

• a first set of plates (110) slidably mounted on said shaft (235);

• arms fitted on said first set of plates (110) in a one-to-one correspondence;

• fixtures provided at free end of each of said arms for replaceably receiving microfinishing tools; and

• a spacing mechanism for varying the distance between said plates (110) of said first set in a controlled manner for performing the microfinishing operation; characterized in that: said spacing mechanism comprises a second set of plates (115) angularly displaceable by said shaft (235) to vary the distances between adjacent arms and thereby between tools attached to said arms in an operative configuration for performing a microfinishing operation on said component.

2. The machine (200) as claimed in claim 1, wherein said plates (110) of said first set of plates and said plates (115) of said second set of plates are cam plates.

3. The machine (200) as claimed in claim 1, wherein each of said plates (115) of said second set of plates is provided with a plurality of protrusions of different lengths, wherein said protrusions are configured to selectively abut a corresponding plate (110) of said first set of plates.

4. The machine (200) as claimed in claim 3, wherein each plate (110) of said first set of plates is configured with at least one slot (120), wherein said slot is configured to receive non-abutting protrusions of a corresponding plate (115) of said second set of plates.

5. The machine (200) as claimed in claim 1, wherein said plates (110) of said first set of plates and said plates (115) of said second set of plates are mounted adjacently and alternatingly on said shaft (235).

6. The machine (200) as claimed in claim 3, wherein said plurality of protrusions are configured in a plurality of sets of protrusions (130, 135, 140) of different lengths and wherein the protrusions in each set have the same height and said protrusions are configured on each of said plates (115) of said second set of plates in an alternating and interspersing fashion.

7. The machine (200) as claimed in claim 6, wherein each plate (110) of said first set of plates is provided with a plurality of slots (120) equal in number to the protrusions in each set on said plate (115) of said second set of plates and each slot (120) is configured to receive one protrusion each of the non-abutting sets of protrusions.

8. The machine (200) as claimed in claim 6, wherein angle between two protrusions of each set is equal to 360 number of protrusions per set/number of sets of protrusions.

9. The machine (200) as claimed in claim 4, wherein a predetermined lateral pressure is applied on said arms for facilitating abutment of operative top ends of protrusions on each of said plates (115) of said second set of plates on an opposing surface of a corresponding plate (110) of said first set of plates, thus maintaining a fixed axial distance between adjacent plates and thereby between adjacent arms attached to said plates (110) of said first set of plates.

10. The machine (200) as claimed in claim 9, wherein, when said pressure is removed, a plate (110) of said first set of plates and a plate (115) of said second set of plates are separated axially, due to resilience of a resilient member (240) which is configured to maintain a distance between said plate (110) and said plate (115) which is sufficient to facilitate rotation of a plate (115) of said second set of plates without collision of side walls of protrusions against inner walls of said slots (120).

11. The machine (200) as claimed in claim 3, wherein said plates (115) of said second set of plates are rotated to change the abutting protrusions from those of one length to another length using a mechanism comprising a pneumatic cylinder assembly (210), a rack (215) and pinion (220) arrangement and a chain (230) and sprocket (225) arrangement.

12. The machine (200) as claimed in claim 4, wherein said plate (115) of said second set of plates is provided with a first set of protrusions (130), a second set of protrusions (135), and a third set of protrusions (140), and a corresponding plate (110) of said first set of plates is provided with three slots (120).

13. The machine (200) as claimed in claim 12, wherein an angle between a protrusion of the first set of protrusions (130) and a consecutive protrusion of the second set of protrusions (135) is 35° and an angle between a protrusion of the second set of protrusions (135) and a consecutive protrusion of the third set of protrusions (140) is 40°.

Description:
A MACHINE FOR PERFORMING MICROFINISHING OPERATION ON A

COMPONENT

FIELD

The present invention relates to the field of microfinishing machines. DEFINITIONS

As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.

The expression 'microfinishing' used hereinafter in this specification refers to, but is not limited to, a process of abrasive removal of a thin amorphous surface layer of a machined component in order to impart a desired fine texture to the surface of the component. The fine texture imparted by microfinishing process, is usually, but not limited to, a cross-hatch pattern. The removed layer is usually about 1 μπι in thickness. The abrasive tool used for material removal may be an abrasive stone or a tape. Microfinishing is also known as 'superfinishing', 'micromachining' , 'short-stroke honing' and the like.

BACKGROUND Microfinishing operation is an essential process for many components. For example, in case of manufacturing of a camshaft or crankshaft, the microfinishing operation plays an important role. Many components are typically micro-finished before assembling them with any other components. Conventionally, a microfinishing machine has multiple tools configured to achieve surface finishing of multiple features of a component. These tools are commonly referred as microfinishing arms. For completing each process, a dedicated microfinishing arm is provided. Typically, many variants of the same component are operated on a single microfinishing machine. In different variants of the components, centre distance between the features of the component varies, because of which the distance between the microfinishing arms is required to be altered in correspondence with variation in the centre distance between the features. Conventionally, the distance between the microfinishing arms is altered by manually replacing spacers or by using automatic arm shifting mechanism. However, manual replacement of the spacers consumes lot of time and is highly dependent on an operator's skill. The automatic arm shifting mechanism requires servo motors to change the distance between the microfinishing arms. However, the use of servo motors makes the automatic arm shifting mechanism expensive, and unreliable.

Therefore, there is felt a need for a machine for microfinishing with a mechanism for varying distance between the microfinishing arms, that alleviates the abovementioned drawbacks of the conventional methods. OBJECTS

An object of the present disclosure is to provide a machine for performing microfinishing operation on a component, wherein the machine is provided with a spacing mechanism whose operation is time-effective.

Another object of the present disclosure is to provide a machine for performing microfinishing operation on a component, wherein the machine is provided with a spacing mechanism that is cost-effective.

Yet another object of the present disclosure is to provide a machine for performing microfinishing operation on a component, wherein the machine is provided with a spacing mechanism that is reliable. Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY

The present disclosure envisages a machine for performing microfinishing operation on a component. The machine comprises a rotatable shaft, means for rotating the rotatable shaft, a first set of plates slidably mounted on the shaft, arms fitted on the first set of plates in a one- to-one correspondence, fixtures provided at free end of each of the arms for replaceably receiving microfinishing tools, a spacing mechanism for varying the distance between the plates in the first set in a controlled manner for performing the microfinishing operation. The spacing mechanism comprises a second set of plates angularly displaceable by the shaft to vary the distances between adjacent arms and thereby between tools attached to the arms in an operative configuration for performing a microfinishing operation on the component.

In an embodiment, the plates of the first set of plates and the plates of the second set of plates are cam plates. In another embodiment, each of the plates of the second set of plates is provided with a plurality of protrusions of different lengths. The protrusions are configured to selectively abut a corresponding plate of the first set of plates. Preferably, each plate of the first set of plates is configured with at least one slot. The slot is configured to receive non-abutting protrusions of a corresponding plate of the second set of plates. In a preferred embodiment, the plurality of protrusions is configured in a plurality of sets of protrusions of different lengths. The protrusions in each set have the same height. The protrusions are configured on each of the plates of the second set of plates in an alternating and interspersing fashion. Each plate of the first set of plates is provided with a plurality of slots equal in number to the protrusions in each set on the plate of the second set of plates. Each of these slots is configured to receive one protrusion each of the non-abutting sets of protrusions. Angle between two protrusions of each set is equal to 360 number of protrusions per set/number of sets of protrusions. In an embodiment, the plate of the second set of plates is provided with a first set of protrusions, a second set of protrusions, and a third set of protrusions, and a corresponding plate of the first set is provided with three slots. In another embodiment, an angle between a protrusion of the first set of protrusions and a consecutive protrusion of the second set of protrusions is 35° and an angle between a protrusion of the second set of protrusions and a consecutive protrusion of the third set of protrusions is 40°.

Preferably, the plates of the first set and the plates of the second set are mounted adjacently and alternatingly on the shaft. Preferably, a predetermined lateral pressure is applied on the arms for facilitating abutment of operative top ends of protrusions on each of the plates of the second set of plates on an opposing surface of a corresponding plate of the first set of plates, thus maintaining a fixed axial distance between adjacent plates and thereby, between adjacent arms attached to the plates of the first set of plates. Further, when the pressure is removed, a plate of the first set of plates and a plate of the second set of plates are separated axially, due to resilience of a resilient member which is configured to maintain a distance sufficient to facilitate rotation of a plate of the second set of plates without collision of side walls of protrusions against inner walls of the slots. According to a preferred embodiment, the plates of the second set of plates are rotated to change the abutting protrusions from those of one length to another length using a mechanism comprising a pneumatic cylinder assembly, a rack and pinion arrangement and a chain and sprocket arrangement.

DESCRIPTION OF RELATED DRAWING

A machine for performing microfinishing operation on a component, wherein the machine is provided with a spacing mechanism of the present disclosure, will now be described with the help of the accompanying drawing, in which: Figure 1 illustrates a schematic view depicting a machine for performing microfinishing operation on a component, provided with a spacing mechanism, according to the present disclosure;

Figure 2a illustrates an isometric view of a pair of plates in a spacing mechanism of the machine in accordance with an embodiment of the present disclosure; Figure 2b illustrates another isometric view of a pair of plates in a spacing mechanism of a machine in accordance with an embodiment of the present disclosure;

Figure 3 illustrates a front view depicting a first operative configuration of a pair of plates in a spacing mechanism of a machine in accordance with an embodiment of the present disclosure; Figure 4 illustrates a side view of the pair of plates in the spacing mechanism of Figure 2;

Figure 5 illustrates a front view depicting a second operative configuration of a pair of plates in a spacing mechanism of a machine in accordance with an embodiment of the present disclosure;

Figure 6 illustrates a side view of the pair of plates in the spacing mechanism of Figure 4; Figure 7 illustrates an isometric view depicting a third operative configuration of a pair of plates in a spacing mechanism of the machine in accordance with an embodiment of the present disclosure; Figure 8 illustrates a side view of the pair of plates in spacing mechanism of figure 6; and

Figure 9, Figure 10, and Figure 11 illustrate schematic views depicting various positions of an actuating mechanism configured to rotate the plates of the second set of the spacing mechanism of the microfinishing machine. LIST OF REFERENCE NUMERALS

200 - Machine for microfinishing

100 - Spacing mechanism

110 - First set of plates

115 - Second set of plates 120 - Slots

125 - Hole

130 - First set of protrusions

135 - Second set of protrusions

140 - Third set of protrusions 210 - Pneumatic cylinder assembly

215 - Pinion

220 - Rack

225 - Sprocket

230 - Chain 235 - Shaft

240 - Resilient member DETAILED DESCRIPTION

The present disclosure envisages a machine for performing microfinishing operation on a component, wherein the machine is provided with a spacing mechanism, and wherein the spacing mechanism effectively facilitates varying the centre distance between microfinishing arms or units and thereby between microfinishing tools replaceably received on fixtures provided on free ends of the arms.

The spacing mechanism, of the present disclosure, is now described with reference to Figure 1 through Figure 8.

Figure 1 illustrates a schematic view depicting a machine 200 for performing microfinishing operation on a component, wherein the machine 200 is provided with a spacing mechanism 100. The spacing mechanism 100 comprises of a plurality of plates 110 of a first set and a plurality of plates 115 of the second set. The positions of the plurality of plates 110 of the first set and plates 115 of the second set in the microfinishing machine 200 are shown in Figure 1. To adjust the spacing between the microfinishing arms and thereby between the microfinishing tools according to component variants, the plurality of plate pairs - each containing a plate from the first and the second set - is used. According to an embodiment, the spacing between the arms and thereby the microfinishing tools is determined by the height of the protrusions on the plate 115 of the second set abutting on the operative inner surface of the plate 110 of the first set. To vary the spacing between the arms according to part variants, the plate 115 of the second set is rotated through a predetermined angle. A hydraulic or pneumatic pressure is applied on lateral ends of arms to maintain the plate 110 of the first set and the plate 115 of the second set in a state of abutment. Resilient members 240, which is a plurality of springs, shown in Figure 1 are configured to separate the plates 110 of the first set and the plates 115 of the second set.

Figure 2a and Figure 2b illustrate isometric views of a pair of plates in the spacing mechanism 100, in accordance with an embodiment of the present disclosure. The plate 110 has a plurality of slots 120 configured thereon. In an embodiment, the plate 110 has three slots 120. However, the number of slots 120 can vary according to application. Further, a plurality of holes is provided at each corner of the plate 110 of the first set to facilitate attachment of the plate 110 with fixed end of an arm, preferably an arm provided with a fixture at its free end on which a microfinishing tool is replaceably received. The plate 110 includes a hole 125 configured at the centre to allow mounting on a shaft 235.

In an embodiment, the plates 110 of the first set and plates 115 of the second set are cam plates. Each plate 115 of the second set is configured with a plurality of protrusions extending from an operative surface of the plate 115. The plurality of protrusions has different heights. In an embodiment, the plurality of protrusions includes three sets of protrusions, wherein each set has different height. More specifically, the plurality of protrusions includes a first set of protrusions 130, a second set of protrusions 135, and a third set of protrusions 140.

In an embodiment, the height of each protrusion of the first set of protrusions 130 is lesser than that of the second set of protrusions 135 and third set of protrusions 140. The height of each protrusion of the second set of protrusions 135 is lesser than that of the third set of protrusions 140. Each protrusion in the same set of protrusions has same height as that of other protrusions in that set.

In another embodiment, the first set of protrusions 130, the second set of protrusions 135, and the third set of protrusions 140 are arranged alternatively at the circumference of the plate 115 of the second set such that no protrusions of the same set of protrusions is positioned consecutively. More specifically, a protrusion of the second set of protrusions 135 is arranged or positioned between a protrusion of the first set of protrusions 130 and a protrusion of the third set of protrusions 140. A protrusion of the third set of protrusions 140 is arranged or positioned between a protrusion of the second set of protrusions 135 and a protrusion of the first set of protrusions 130. In an embodiment, each protrusion has a different height than that of the consecutive protrusion.

Although the present disclosure is described with reference to three sets of protrusions, the spacing mechanism 100 can comprise more than three sets of protrusions depending on application. In an embodiment, instead of protrusions, extruding surfaces are formed on the operative surface of the plate 115 of the second set. In an exemplary embodiment, the plate 115 includes two extruding surface having different heights.

The three sets of protrusions or the extruding surfaces of the plate 115 of the second set are configured to abut a corresponding plate 110 of the first set.

In an embodiment, an angle between a protrusion of the first set of protrusions 130 and a consecutive protrusion of the second set of protrusions 135 is 35°. In another embodiment, an angle between a protrusion of the second set of protrusions 135 and a consecutive protrusion of the third set of protrusions 140 is 40°. The plate 115 of the second set is angularly displaced, i.e., rotated by the shaft 235 to vary the distance between adjacent microfinishing arms.

The operative configuration of the spacing mechanism 100 is now described with reference to Figure 2 through Figure 7.

Figure 2 and Figure 3 illustrate a first operative configuration of a pair of plates in the spacing mechanism 100.

In the first operative configuration, the first set of protrusions 130 abuts the plate 110 of the first set, thereby maintaining an axial distance between the plate 110 of the first set and the plate 115 of the second set. The axial distance is equal to the height of each protrusion of the first set of protrusions 130. In an embodiment, the axial distance between the plate 110 of the first set and the plate 115 of the second set is 5 mm in the first operative configuration. In this configuration, a first distance is maintained between adjacent microfinishing arms and thereby between adjacent microfinishing tools attached thereon.

When the first set of protrusions 130 abut the plate 110 of the first set, the protrusions of the second set of protrusions 135 and the third set of protrusions 140 are received within the slots 120 configured on the plate 110 of the first set.

Figure 4 and Figure 5 illustrate a second operative configuration of the spacing mechanism 100. In the second operative configuration, the plate 115 of the second set is rotated by a predetermined angle, which is equal to an angle between a protrusion of the first set of protrusions 130 and a consecutive protrusion of the second set of protrusions 135. The plate 115 of the second set is rotated such that each protrusion of the second set of protrusions 135 abuts the operative inner surface of the plate 110 of the first set, thereby maintaining the axial distance between the plate 110 of the first set and the plate 115 of the second set. The axial distance is equal to the height of each protrusion of the second set of protrusions 135. In an embodiment, the axial distance between the plate 110 of the first set and the plate 115 of the second set is 7 mm in the second operative configuration. In this configuration, a second distance is maintained between adjacent microfinishing arms greater than the first distance maintained in the first operative configuration.

When the second set of protrusions 135 abut the plate 110 of the first set, the protrusions of the first set of protrusions 130 and the third set of protrusions 140 are received within the slots 120 configured on the plate 110 of the first set. Figure 6 and Figure 7 illustrate a third operative configuration of the spacing mechanism 100.

In the third operative configuration, the plate 115 of the second set is rotated by a predetermined angle, which is equal to an angle between a protrusion of the second set of protrusions 135 and a consecutive protrusion of the third set of protrusions 140. The plate 115 of the second set is rotated such that each protrusion of the third set of protrusions 140 abuts the operative surface of the plate 110 of the first set, thereby maintaining the axial distance between the plate 110 of the first set and the plate 115 of the second set. The axial distance is equal to the height of each protrusion of the third set of protrusions 140. In an embodiment, the axial distance between the plate 110 of the first set and the plate 115 of the second set is 9 mm in the third operative configuration. In this configuration, a third distance is maintained between adjacent microfinishing arms greater than the first distance and the second distance maintained in the first and the second operative configurations respectively.

The height of protrusions in each set of protrusions is determined with respect to the required axial distance between the plate 110 of the first set and the plate 115 of the second set, more specifically with respect to the required distance between adjacent microfinishing arms of the machine for performing microfinishing operation and thereby distance between microfinishing tools attached thereon. In an embodiment, the plate 115 of the second set is rotated manually. In another embodiment, the plate 115 of the second set is rotated via a hydraulically operated mechanism.

Figure 9, Figure 10, and Figure 11 illustrate schematic views depicting various positions of an actuating unit of the microfinishing machine configured to rotate the plates 115 of the second set of the spacing mechanism 100. The actuating unit of the microfinishing machine 200 comprises a pneumatic cylinder assembly 210. In an embodiment, the pneumatic cylinder assembly 210 includes two pneumatic cylinders arranged back to back. Typically, the pneumatic cylinders are 3-position pneumatic cylinders. The shaft 235 of the microfinishing machine 200 is coupled with a chain and sprocket arrangement 225, 230. The pneumatic cylinder assembly 210 is coupled with the chain and sprocket arrangement 225, 230 via a rack and pinion arrangement 215, 220. More specifically, the rack 220 is coupled with the pneumatic cylinder assembly 210 and with the pinion 215. The pinion 215 is concentrically mounted on one of the sprockets 225. The chain 230 is configured to facilitate transmission of motion from one sprocket to another sprocket. In an embodiment, actuation of the pneumatic cylinder assembly 210 is controlled by a computerized numerical control machine via a solenoid valve.

When the distance between the arms and thereby the microfinishing tools needs to be changed, the hydraulic or pneumatic pressure on the microfinishing arms, which is applied on lateral ends of arms, is removed. The springs 240 are configured to maintain a distance sufficient to facilitate rotation of a plate of the second set of plates without collision of side walls of protrusions against inner walls of the slots. Due to removal of the pressure and resilience of springs 240, the plates 110 of the first set and the plates 115 of the second set are pulled apart out of the state of abutment. By actuating the 3-position pneumatic cylinder 210, rack and pinion arrangement 215, 220 and chain and sprocket arrangement 225,230, the plate 115 of the second set is rotated to change the abutting set of protrusions from one set to another. Specifically, for example, the abutting set of protrusions is changed from set 140 to set 130. Hence, pressure is applied back on the microfinishing arms. Therefore, protrusions 130 are now in abutting state and protrusions 135 and 140 get inserted into the slots 120 in the plate 110 of the first set. In this manner, the axial distance between the plates 110 and 115 of the first and the second sets respectively is changed from a first distance to a second distance and thereby changing the distance between adjacent arms and hence adjacent microfinishing tools attached to the plates 115 of the second set. In the example where the abutting set of protrusions is changed from set 140 to set 130 as shown in Figure 7 and Figure 3, the axial distance between the plates 110 and 115 of the first and the second sets respectively increases, and therefore the distance between adjacent microfinishing tools is increased.

Although working of the spacing mechanism 100 is described with reference to the microfinishing machine, the spacing mechanism 100 can be used for any machine or equipment where spacing between the components or units of the machine needs to be altered.

The spacing mechanism of the present disclosure has a simple configuration, and is economical compared to conventional methods.

TECHNICAL ADVANCEMENTS

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a spacing mechanism that:

• is time-effective;

• is cost-effective; and

• is reliable.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.

Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary. While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.