Abstract:
A vacuum cleaner of the fixed or floating nozzle type wherein a spring is utilized for urging the suction nozzle into the carpet pile to maintain and improve nozzle suction over a wide range of carpet pile heights and types. Such cleaners often lose nozzle suction as the pile height of the carpet increases and forces the suction nozzle upward away from the carpet. The addition of a spring to force the suction nozzle downward restores and improves nozzle suction and thereby improves overall cleaning efficiency of the vacuum cleaner.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention pertains to a spring loaded nozzle arrangement for increasing the loading on the nozzle for improved cleaning performance. 
     2. Background Information 
     Upright vacuum cleaners are well known in the art. Typically, these upright vacuum cleaners include a vacuum cleaner housing pivotally mounted to a vacuum cleaner foot. The foot is formed with a nozzle opening and may include an agitator mounted therein for loosening dirt and debris from a floor surface. A motor may be mounted in either the foot or the housing for producing suction at the nozzle opening. The suction at the nozzle opening picks up the loosened dirt and debris and produces a stream of dirt-laden air which is ducted to the vacuum cleaner housing for collection and later disposal. 
     In conventional vacuum cleaners, the nozzle is suspended over the floor surface to be cleaned so that a pre-determined distance is maintained. Typically, the cleaner wheels are positioned so that the nozzle is supported above the floor surface the desired distance. The distance is selected so that nozzle suction is maintained on the floor surface to be cleaned while allowing air flow into the suction nozzle. Both nozzle suction and air flow into the nozzle are necessary for satisfactory cleaning efficiency. The distance the nozzle needs to be suspended over the surface to be cleaned to maintain satisfactory nozzle suction and air flow varies according to the type of carpeting and the pile height. Some cleaners allow this distance to be adjusted for varying carpet pile heights by the user moving a knob or dial on the foot of the cleaner. However, this isn&#39;t completely satisfactory since such cleaners don&#39;t have a setting to accommodate every carpet pile height. One setting may be too high and the next lower setting may be too low. Even when a cleaner is set to a lower setting, nozzle suction is lost because the underside of the nozzle has a tendency to be lifted from the carpet by the thicker pile. Hence, cleaning efficiency is reduced. It has been found that loading the nozzle with weight or the equivalent forces the nozzle deeper into the pile of the carpet and nozzle suction is improved. Thus, cleaning efficiency may be maintained on carpets of all pile heights. 
     There exists in the prior art patents for a vacuum cleaner having a spring means to urge the nozzle towards the floor surface. For example, U.S. Pat. No. 3,676,892 issued to Nordeen discloses a vacuum cleaner having an elongated floor portion propellable over a floor during cleaning and supported on the floor by a plurality of spaced front and rear wheels. A nozzle unit forms the floor portion of the cleaner and has a front suction opening end carrying a floor contacting brush and is rockable or pivotable in a vertical direction with respect to the wheels. A first spring means constantly urges the carriage downwardly at the front end to hold the brush in a cleaning position with respect to the floor regardless of the nature of the floor or its covering. A propelling handle is rockably attached to the cleaner and movable between an operating position and a storage position. A second spring means stronger than the first and operably positioned between the front wheels and the front is operably positioned between the front wheels and the front suction end of the nozzle unit. Means operated by the handle when the handle is moved to the storage position distorts the second spring means to apply an overcoming spring force to retain the nozzle unit front end away from the floor against the urging of the first spring means. The cleaner can then be operated in the customary off-the-floor cleaning of furniture, draperies and the like by the use of auxiliary equipment without permitting the brush to contact the floor. 
     U.S. Pat. No. 5,819,370 issued to Stein and the corresponding foreign patent publications, namely, Federal Republic of Germany Patent Application No. 195 05 106.8, filed on Feb. 16, 1995, DE-OS 195 05 106.8, and DE-PS 195 05 106.8, and European Patent Applications EP 0 727 171 A3 and EP 0 727 171 A3 describe a floorcare machine wherein the brush roller is pressed against the surface to be cleaned by a means of a spring element. The brush roller is pivotally mounted in the housing and is biased against the floor surface by means of a tension spring, or alternately, a torsional spring. The tension spring biases the roller toward the floor surface being operatively connected at the rear of the housing between the top of the housing and the inner part the roller is rollably mounted within. The torsional spring biases the roller downward toward the floor surface by being operatively mounted about the pivot the inner part is mounted onto the housing with. 
     However, neither of these references describe a vacuum cleaner having a means for urging the nozzle toward the surface to be cleaned and selectively allowing the user to adjust the height in which the nozzle is suspended over the floor surface. Consequently, there is a need in the art for a new and improved arrangement for loading a vacuum cleaner nozzle that also has a means to select the height which the nozzle is suspended over the carpet or surface to be cleaned while simultaneously urging the nozzle into the carpet pile regardless of the height of the carpet pile. The present invention fulfills this need by providing a vacuum cleaner having a means for adjusting the distance the nozzle is suspended over the carpet or surface to be cleaned while maintaining a biasing force on the nozzle to continuously urge the nozzle into the carpet pile regardless of the carper pile height. 
     Accordingly, an object of the present invention is to provide a spring loaded nozzle for a vacuum cleaner for improving cleaning performance on carpets of varying pile heights. 
     Another object of the present invention is to provide a spring loaded nozzle to improve nozzle suction while maintaining satisfactory air flow into the nozzle. 
     Yet another object of the present invention is to provide a spring loaded nozzle for suction nozzles of the fixed type. 
     Still yet another object of the present invention is to provide a spring loaded nozzle for suction nozzles of the floating type. 
     These and other objects will be readily apparent to one of skill in the art upon reviewing the following description and accompanying drawings. 
     SUMMARY OF THE INVENTION 
     In the preferred embodiment of the present invention, an upright vacuum cleaner is provided of the floating nozzle type. Such cleaners are typically comprised of an upright portion pivotally connected to a vacuum cleaner foot. The foot is generally comprised of a main body, an agitator housing pivotally connected to the main body, an agitator mounted within the agitator housing, and a hood covering the foot. The agitator housing is biased downward by a spring member such as a compression spring in operative engagement with the agitator housing to urge the nozzle towards the surface to be cleaned or the carpet pile. The vacuum cleaner may or not have a power drive unit in the foot to propel the foot over the floor surface 
     In an alternate preferred embodiment of the present invention, an upright vacuum cleaner is provided of the fixed nozzle type. Such cleaners are typically comprised of an upright portion pivotally connected to a vacuum cleaner foot. The foot is generally comprised of an agitator housing and an agitator mounted within the agitator housing. The vacuum cleaner may or not have a power drive unit in the foot to propel the foot over the floor surface. A least one spring member such as a coil spring or torsional spring is in operative engagement with the upper portion of the vacuum cleaner and the foot to urge the agitator housing and the nozzle towards the surface to be cleaned or the carpet pile. The vacuum cleaner may or not have a power drive unit in the foot to propel the foot over the floor surface 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a vacuum cleaner of the floating nozzle type, according to one embodiment of the present invention; 
     FIG. 2A is an exploded perspective view of the lower portion of the vacuum cleaner shown in FIG. 1; 
     FIG. 2B is an exploded perspective view of the lower portion of a vacuum cleaner like the one shown in FIG. 1, according to the third embodiment of the invention; 
     FIG. 2C is an exploded perspective view of the lower portion of a vacuum cleaner like the one shown in FIG. 1, according to the fourth embodiment of the invention; 
     FIG. 2D is an exploded perspective view of the lower portion of a vacuum cleaner like the one shown in FIG. 1, according to the fifth embodiment of the invention; 
     FIG. 2E is an exploded perspective view of the lower portion of a vacuum cleaner like the one shown in FIG. 1, according to the sixth embodiment of the invention; 
     FIG. 3A is a side view of the vacuum cleaner of FIG. 1 with a cutaway view of the region surrounding the agitator housing loading spring; 
     FIG. 3B is a side view of the vacuum cleaner of FIG. 1 with a cutaway view of the region surrounding the agitator housing loading spring found in the preferred embodiment of the invention and the location of the torsional springs found in the third, fourth and fifth embodiments of the present invention; 
     FIG. 3C is a front view of the foot portion of the vacuum cleaner of FIG. 1 with a cutaway view of the region surrounding the agitator housing loading spring with the carpet height selector in the highest carpet height position; 
     FIG. 3D is a front view of the foot portion of the vacuum cleaner of FIG. 1 with a cutaway view of the region surrounding the agitator housing loading spring with the carpet height selector in the lowest carpet height position; 
     FIG. 4 is a perspective view of the vacuum cleaner of FIG. 1 with a portion of the hood cutaway in the region surrounding the agitator housing loading spring; 
     FIG. 5 is a top view of the vacuum cleaner of FIG. 1 with a portion of the hood cutaway in the region surrounding the agitator housing loading spring; 
     FIG. 6A is an exploded perspective view of the lower portion of a vacuum cleaner of fixed nozzle type found in a vacuum cleaner such as the one seen in FIG. 1, according to the second embodiment of the present invention; 
     FIG. 6B is an exploded perspective view of the lower portion of a vacuum cleaner of fixed nozzle type found in a vacuum cleaner such as the one seen in FIG. 1, according to the sixth embodiment of the present invention; 
     FIG. 7A a  is an exploded perspective and partially cutaway view of a portion of the right side of the foot and motor housing of the vacuum cleaner shown in FIG. 6; and 
     FIG. 7B is a fully exploded perspective and partially cutaway view of a portion of the right side of the foot and motor housing of the vacuum cleaner shown in FIG. 6 showing the detail of the installation of a torsional spring inside a trunnion; and 
     FIG  8  is a side view of the vacuum cleaner shown in FIG.  6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A vacuum cleaner having a spring-loaded nozzle of the floating nozzle type is shown in FIG.  1  and generally indicated as  10 , according to the preferred embodiment of the present invention. The cleaner  10  shown is an upright vacuum cleaner but the scope of the invention in the preferred embodiment also includes other vacuum cleaners having a floating suction nozzle, including but not limited to, canister vacuums. Vacuum cleaner  10  includes a handle  20 , a bag housing  30 , and a vacuum cleaner foot  50 . A source of suction such as suction fan motor (not shown) is enclosed in a motor housing  40  located on the lower end of the bag housing  30 . Vacuum cleaner foot  50  is pivotally connected to bag housing  30  via motor housing  40 . Bag housing  30  holds a filter media and receptacle  31  for filtering and collecting particulate matter from an airstream drawn through a suction nozzle inlet area (not shown) on the underside of foot  50  by the suction motor. In the preferred embodiment of the invention, the filter media and receptacle  31  located within bag housing  30  is a filter bag. In an alternate embodiment of the present invention, the filter media and receptacle  31  are cyclonic action which deposits particulate matter into a receptacle such as a dirt cup for later disposal. The suction nozzle inlet opening (not shown) opens toward the floor surface to be cleaned. A conventional agitator (not shown) is positioned within an agitator chamber (not shown) which communicates with the nozzle opening inlet area. The agitator rotates about a horizontal axis for loosening dirt and particles from the floor surface and carpet for collection and later disposal. The agitator may be rotated by the suction-fan motor or other rotary power source. 
     Referring now to FIGS. 2 and 3, foot  50  is comprised of a hood  51  and agitator housing  53  which is pivotally connected to main body  56 . Bag housing  30  holds a filter media and receptacle  31  for filtering and collecting particulate matter from an airstream drawn into agitator chamber  53   a  through a suction nozzle inlet area  53   b  on the underside of foot  50  created by the suction motor  42 . In the preferred embodiment of the invention, filter media and receptacle  31  is a filter bag. In an alternate embodiment of the invention, filter media and receptacle  31  may be a dirt cup which removes the particles from the airstream by cyclonic action. In another alternate embodiment of the invention, filter media and receptacle  31  may be a dirt cup having a filter located therein for filtering particles. Main body  56  has a pair of opposing semi-circular shaped recesses  57  for receiving a complementary pair of opposing trunnions  41  located on motor housing  40 . A trunnion cover  59  secures each of opposing trunnions  41  within recesses  57  of main body  56 . Trunnion covers  59  are secured using screws or the like. A pair of wheels  60  are located on opposing sides of main body  56  for supporting main body  56  on a surface to be cleaned. Connected to the front side of main body  56  is power drive unit  70  having a pair of opposing drive wheels  71  for propelling foot  50  on a surface and supporting main body  56  on the surface. Power drive unit  70  may be powered by the suction-fan motor  42  or other source of rotary power. As is typical with power drive units such as the one shown, a linkage or other member from the handle  20  (shown in FIG. 1) causes the rotary power to be selectively connected to the power drive unit  70 . 
     Agitator housing  53  is pivotally connected to main body  56  via a pair of inwardly facing opposing pivots  54  located on agitator housing  53 . Pivots  54  are received by a complementary pair of pivot recesses  58  located on main body  56 . Pivot recesses  58  are semi-circular shaped so that pivots  54  may rotate freely therein. A second pair of trunnion covers  62  secure pivots  54  in pivot recesses  58 . Agitator housing  53  and hood  51  are thereby free to pivot relative to main body  56  as a unit. Power drive unit  70  is designed to fit within a open region between the lateral sides of agitator housing  53 . Since power drive unit  70  is fixed rigidly to main body  56 , agitator housing  53  is free to move relative to power drive unit  70 . A loading spring arm  72  projects forwardly from power drive unit  70  over onto the upper surface of agitator housing  53 . At the free end of loading spring arm  72 , a compression spring  55  is inserted between the lower side of loading spring arm  72  and the upper surface of agitator housing  40 . The upper side of loading spring arm  72  bears against the underside of carpet height selector  53  positioned in a track in hood  51 . The underside of carpet height selector  52  is cammed so that as carpet height selector  52  is moved laterally the amount of force applied to loading spring arm  72  is varied. This arrangement allows a varying amount of force to be applied to the upper surface of agitator housing  53  to force agitator housing  53  in the direction of arrow  80  into the carpet pile to maintain nozzle suction. When vacuum cleaner  10  is in use, there is a tendency for agitator housing  53  to be lifted from the carpet as the carpet pile height increases thereby reducing nozzle suction and cleaning efficiency. As the height of the carpet pile increases, more force may be applied to agitator housing  53  by compression spring  55  by adjusting the position of carpet height selector  52 . Likewise, as the height of the carpet pile height is reduced, less force is required to maintain nozzle suction so carpet height selector  52  may be adjusted to reduce the force placed on agitator housing  53  through compression spring  55 . It has been found that a force placed on agitator housing  53  in an amount equivalent to the weight of between one-half pound to two pounds in the direction of arrow  80  has been effective in restoring nozzle suction lost due to the suction nozzle being be lifted by the pile of carpets. However, this is in no way meant to be limiting as the actual amount of force varies from carpet to carpet according to pile height, pile type, and other factors. The characteristics of compression spring  55  are chosen such that compression spring  55  will place a force in this range on agitator housing  53 . The actual amount of force is determined by the amount of force placed onto compression spring  55  by the cammed portion on the underside of carpet height selector  52 . Foot assembly  50  is also equipped with an agitator shutoff assembly  61  on hood  51  which disengages rotary power from the agitator  63  when put in the off position. 
     The floating nozzle design allows the force being applied to agitator housing  53  to be maintained even as bag housing  30  is pivoted about foot  50  in the direction of arrow  81 . In an alternate embodiment of the present invention, the power drive unit  70  has been omitted and replaced with a pair of conventional wheels for supporting the front portion of foot  50  on a surface. Loading spring arm  72  may be attached directly to main body  56  or other suitable attachment point within the interior of foot  50 . 
     Referring now to FIG. 4, compression spring  55  is seen through a cutaway portion in the top of hood  51 . A portion of the track which carpet selector  52  (not shown) slides in is seen to the left of the cutaway area. Loading spring arm  72  is seen attached to power drive unit  70  and extends over agitator housing  53  to provide a fixed point for the top end of compression spring  55  to bias against and to transmit the downward force from the cammed portion on the underside of the carpet selector  52  (not shown) to spring  51 . This is also demonstrated in a top view in FIG.  5 . 
     Referring now to FIG. 6, a lower portion of a vacuum cleaner having a spring-loaded nozzle of the fixed nozzle type is shown and is generally indicated as  110 , according to an alternate embodiment of the present invention. The portion of the cleaner  110  shown is of an upright vacuum cleaner but the scope of the invention in the alternate embodiment also includes other vacuum cleaners having a fixed suction nozzle, including but not limited to, canister vacuums. Such cleaners generally have a suction nozzle portion having a nozzle inlet area for placement over the surface to be cleaned and an upright portion pivotally connected to the suction nozzle portion. The vacuum cleaner  110  shown in FIG. 6 includes a bag housing  130 , a motor housing  140  and a foot  150 . Foot  150  is comprised of an agitator housing  153 , a wheel carriage  170 , and hood  151 . Bag housing  130  holds a filter media and receptacle  131  for filtering and collecting particulate matter from an airstream drawn into a suction nozzle inlet area  153   b  on the underside of foot  150  by a suction motor  141  located in motor housing  140 . In the preferred embodiment of the invention, the filter media and receptacle  131  located within bag housing  130  is a filter bag. In an alternate embodiment of the present invention, the filtering media and receptacle  131  is cyclonic action and a dirt cup. In another alternate embodiment of the invention, the filtering media and receptacle  131  is a filter and a dirt cup. The suction nozzle inlet opening  153   b  opens toward the floor surface to be cleaned. A conventional agitator  163  is positioned within an agitator chamber  153   a  which communicates with the nozzle inlet opening  153   b . The agitator rotates about a horizontal axis for loosening dirt from the carpet which is directed to filter media and receptacle  131 . Foot  150  is pivotally connected to bag housing  130  via a pair of opposing trunnions  141  located on opposing sides of motor housing  140 . Trunnion  141  fits into trunnion recess  157  and is secured therein by trunnion cover  159 . Trunnion cover  159  is secured to agitator housing  153  with screws or the like. Trunnion recesses  157  and trunnion covers  159  are semi-circular in shape so that trunnion  141  is free to rotate therein. Before trunnions  141  are placed into trunnion recesses  157 , a torsional spring  155  is installed inside the hollow interior of either of trunnions  141  or both. For illustrative purposes, only one torsional spring  155  is shown being installed in trunnion  141  located on the right side of the cleaner  110 . Further detail of the installation of torsion spring  155  in trunnion  141  is given below in the description of FIGS. 7 a ,  7   b  and  8 . A pair of wheels  160  are located on opposing sides of agitator housing  153  towards the rear for supporting the rear of agitator housing  153  on a surface. A wheel carriage assembly  170  having a pair of opposing wheels  171  is attached to the forward portion of agitator housing  153  to support the forward end of agitator housing  153  on a surface. Hood  151  is attached to the upper side of agitator housing  153 . A carpet height selector  152  is located on the upper side of hood  151  and is mechanically connected with wheel carriage assembly  170 . Wheel assembly carriage  170  is designed so that the wheels  171  can be raised and lowered in height relative to the wheel carriage  170  by sliding carpet height selector  152  laterally. This allows the height in which agitator housing  153  is raised above the surface to be cleaned to be adjusted. However, as with floating type nozzles, there still exists the problem of the foot  150  and the nozzle (not shown) being forced upward by the carpet as the carpet pile height increases. Foot assembly  150  is also equipped with an agitator shutoff assembly  161  on hood  151  which disengages rotary power from the agitator  163  when put in the off position. 
     Referring now to FIGS. 7 a ,  7   b  and  8 , torsional spring  155  is installed inside trunnion  141  such that one of its free ends is secured to trunnion  141  by inserting it into a specially formed notch  142  in the sidewall of trunnion  141 . Trunnion  141  is annular in shape and has an annular recess specially formed therein to receive torsional spring  155 . One of the free ends  159   a  (FIG. 7 b ) of torsional spring  155  may also be prevented from rotating by being placed into a specially formed groove  142  on the inner circumference of trunnion  141 . Torsional spring  155  may have a slight hook formed on the aforementioned free end  159   a  to engage notch  142 . In an alternate embodiment, the aforementioned free end  159   a  may also be straight and engage a specially formed groove on the inner circumference of the recess of trunnion  141 . The other free end  159   b  of torsional spring  155  extends outside of trunnion  141  and is sandwiched between the rear side of trunnion cover  159  and agitator housing  153 . Thus, when trunnion cover  159  is installed, both of the free ends  159   a  and  159   b  of torsional spring  155  are prevented from rotating. Torsional spring  155  is installed such that the potential energy stored in torsional spring  155  is at its greatest when bag housing  130  is in the most upright position. A force in the direction of arrow  183  is created by the free end of torsional spring  155  sandwiched between trunnion cover  159  and agitator housing  153 . This creates a torque on agitator housing  153  and foot  151  in the direction of arrow  180 , urging the suction nozzle inlet area  153   b  underneath the front end of foot  151  into the carpet pile. When bag housing  130  (shown in FIG. 6) is pivoted in the direction of arrow  181 , trunnion  141  grips the attached end  159   a  of torsional spring  155  and causes a rotation of torsional spring  155  in the direction of arrow  182 . Thus, some of the potential energy is stored in torsional spring  155  is released. However, there still remains enough potential energy in torsional spring  155  to create a torque about trunnion  141  in the direction of arrow  180  to urge agitator housing  153  downwardly as the carpet pile tends to force agitator housing  153  upwardly from the surface of the carpet. Torsional spring  155  is selected for its elastic properties such that it produces a torque when bag housing  130  is in the rearmost position and a force in the direction of arrow  180  equivalent to one-half pound to two pounds. As discussed, that amount of force has been found to be effective in restoring nozzle suction lost due to the suction nozzle being lifted by the increasing pile height of carpets. However, this is in no way meant to be limiting as the actual amount of force varies from carpet to carpet according to pile height, type of pile, and other factors. When bag housing  130  is restored to the normal upright position, the potential energy in torsional spring  155  and the torque placed on agitator housing  153  is restored to their maximum value. 
     In a third embodiment of the present invention (FIG.  2 B), compression spring  55  and loading spring arm  72  are replaced in a vacuum cleaner such as the one shown in FIGS. 1 to  5  with one or more torsional springs installed onto pivot(s)  54 , or alternately, inside trunnion(s)  41 . The installation of a torsional spring(s) is similar to the installation of a torsional spring into trunnion(s)  141  of the vacuum cleaner shown in FIGS. 6A to  8 . The torsional spring(s) urge the front of foot  51  downward in the direction of arrow  80  shown in FIGS. 3A-B. 
     In a fourth embodiment of the present invention (FIG.  2 C), one or more torsional springs like the one seen in FIG. 6A are added to a cleaner such as the one shown in FIGS. 1 to  5  in addition to compression spring  55 . The additional torsional spring(s) are installed inside of one or both of trunnions  41  to urge main body  56  away from bag housing  30  which tends to assist compression spring  55  in urging agitator housing  53  towards the floor surface. Alternately, one or more torsional springs can be installed onto one or both of opposing pivots  54  in the manner described in the third embodiment. The added torsional spring(s) aids compression spring  55  in urging agitator housing  53  and the front of foot  51  downward in the direction of arrow  80  shown in FIGS. 3A-B. 
     In a fifth embodiment of the present invention (FIG.  2 D), power drive unit  70  is eliminated and replaced with a wheel carriage having pair of conventional wheels for supporting the front portion of foot  50  on a surface. Loading spring arm  72  may is attached directly to main body  56  or other suitable attachment point within the interior of foot  50 . Compression spring  55  is installed in operative engagement with loading spring arm  72  and agitator housing  53  as previously described. In addition to compression spring  55 , one or more torsional springs like the one seen in FIG. 6A can be added to a cleaner such as the one shown in FIGS. 1 to  5 . The additional torsional spring(s) are installed inside of one or both of trunnions  41  to assist compression spring  55  in urging agitator housing  53  towards the floor surface. Alternately, one or more torsional springs can be installed onto one or both of opposing pivots  54  in the manner described in the third embodiment. The added torsional spring(s) aids compression spring  55  in urging agitator housing  53  and the front of foot  51  downward in the direction of arrow  80  shown in FIGS. 3A-B. 
     In a sixth embodiment of the present invention, a compression spring and a spring loading arm such as those found in the invention described in FIGS. 1 to  5  are installed on a vacuum cleaner such as the one shown in either of FIGS. 1 to  5  (FIG. 2E) or FIGS. 6A to  8  (FIG. 6B) in the area just in front of the motor housing designated as numeral  40  in FIG.  3 A. The arrangement functions identically to the arrangement described in FIGS. 1 to  5  with the exception that the compression spring and spring loading arm bias foot  50  against bag housing  30  downward toward the floor surface to urge agitator housing  53  and agitator  63  into the carpet pile. Such an arrangement may or may not be used in combination with a nozzle height selector such as the one shown on the preferred embodiment shown in FIGS. 1 to  5 . 
     Accordingly, while there has been shown and described herein several embodiments of the present invention, it should be readily apparent to persons skilled in the art that numerous modifications may be made therein without departing from the true spirit and scope of the invention. Accordingly, it is intended for the appended claims to cover all such modifications that come within the spirit and scope of the invention.