Patent Publication Number: US-2011072610-A1

Title: Upright vacuum cleaner having latch mechanism with replaceable stop

Description:
This application is a continuation of U.S. patent application Ser. No. 11/957,971 filed on 17 Dec. 2007, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/878,952, filed on Jan. 5, 2007, the full disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to the floor care equipment field and, more particularly, to an upright vacuum cleaner, equipped with a novel latch mechanism. 
     BACKGROUND OF THE INVENTION 
     A vacuum cleaner is an electro-mechanical appliance utilized to effect the dry removal of dust, dirt and other small debris from carpets, rugs, fabrics or other surfaces in domestic, commercial and industrial environments. In order to achieve the desired dirt and dust removal, most vacuum cleaners incorporate a rotary agitator. The rotary agitator is provided to beat dirt and debris from the nap of the carpet or rug while a pressure drop or vacuum is used to force air entrained with this dirt and debris into the nozzle of the vacuum cleaner. The particulate laden air is then drawn into a dirt collection vessel. The air is then drawn through a filter before being directed through the motor of the suction generator to provide cooling. Finally, the air is filtered to remove any fine particles of carbon from the brushes of that motor or other dirt that might remain in the airstream before being exhausted back into the environment. 
     Upright vacuum cleaners have become evermore popular in recent years. Upright vacuum cleaners typically incorporate a foot or nozzle assembly that is equipped with a suction inlet and a rotary agitator. A canister assembly is pivotably connected to the nozzle assembly. The canister assembly typically houses the suction generator and the dirt collection vessel in the form of a replaceable filter bag or a removable dirt cup. The canister assembly typically includes a control handle. As the vacuum cleaner is manipulated back and forth across the floor with the control handle, the canister assembly pivots with respect to the nozzle assembly so as to allow smooth and efficient operation of the vacuum cleaner. 
     At any time the canister assembly may be positioned in an upright or storage position. Typically a latch mechanism is provided to secure the canister assembly in the storage position. More specifically, past designs have generally included a cam or stop that is usually molded from a lightweight plastic as part of the vacuum cleaner housing. After extended use this cam can become worn and the latch member then becomes ineffective in securing the canister assembly and handle in the upright storage position. 
     The present invention addresses and alleviates this problem. 
     SUMMARY OF THE INVENTION 
     In accordance with the purposes of the present invention as described herein, an upright vacuum cleaner comprises a housing including a nozzle assembly and a canister assembly. The nozzle assembly and canister assembly are pivotably connected together. In addition, the vacuum cleaner includes a suction inlet carried on the nozzle assembly. Both a dirt collection vessel and a suction generator are carried on the housing. Still further, the upright vacuum cleaner includes a latch mechanism for securing the canister assembly in an upright position relative to the nozzle assembly. That latch mechanism is characterized as including (1) an activator having a first cam surface and (2) a replaceable stop wherein the activator is carried on one of the canister assembly and the nozzle assembly and the replaceable stop is carried on the other of the canister assembly and nozzle assembly. 
     Typically the activator is carried on the nozzle assembly and the replaceable stop is carried on the canister assembly. In this arrangement the canister assembly includes a receiver and the replaceable stop is held in that receiver. A fastener, such as a screw, is provided for securing the replaceable stop in the receiver. The replaceable stop includes a second cam surface that cooperates with the first cam surface of the activator to perform the latching and unlatching function. 
     More specifically describing the invention, the nozzle assembly and the canister assembly pivot about a first pivot axis. The activator is pivotably mounted to the nozzle assembly about a second pivot axis that is offset from the first pivot axis. Further, the activator includes a spring biasing the activator into a first position wherein the first cam surface engages the second cam surface to secure the canister assembly in the upright position. In addition, the activator includes a pedal portion whereby the activator is engaged by the operator to pivot the first cam surface about the second pivot axis out of engagement position with the second cam surface so as to release the latch mechanism and allow the canister assembly to pivot relative to the nozzle assembly about the first pivot axis. 
     Still further, the nozzle assembly may include at least one wall defining an opening having a width W receiving the canister assembly. Further, the at least one wall includes an engineered flex wherein the opening expands to a width of W+F to allow the replaceable stop to pass the first cam surface when the canister assembly is forced from the upright position without disengaging the latch mechanism. This structural arrangement effectively prevents damaging the activator, the replaceable stop and either of the cam surfaces when the activator is handled roughly by the operator and the handle is yanked downward from the storage position without engaging the pedal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The accompanying drawing incorporated in and forming a part of this specification, illustrates several aspects of the present invention, and together with the description serves to explain certain principles of the invention. In the drawing: 
         FIG. 1  is a partially broken-away perspective view of the floor cleaning apparatus of the present invention; 
         FIG. 2  is a detailed perspective view of the replaceable stop; 
         FIG. 3  is a detailed, exploded perspective view showing the canister assembly, receiver, replaceable stop and fastener used to hold the replaceable stop in the receiver of the canister assembly; 
         FIG. 4  is a view similar to  FIG. 3  but illustrating the parts fully assembled; 
         FIG. 5  is a detailed perspective view of the activator; 
         FIG. 6   a  is a perspective view showing how the cam surfaces of the replaceable stop and activator mesh to secure the canister assembly in the upright storage position; 
         FIG. 6   b  is a view similar to  FIG. 6   a  but illustrating how the cam surfaces of the activator are pivoted out of the path of the stop to allow the handle and canister assembly to be freely pivoted with respect to the nozzle assembly during operation of the vacuum cleaner; 
         FIG. 7   a  is a top plan view illustrating the engineered flex provided in the wall of the housing of the nozzle assembly; 
         FIG. 7   b  is a schematical view illustrating how the wall of the nozzle assembly with engineered flex allows the replaceable stop and actuator to mesh and lock the handle/canister assembly in the upright, storage position also illustrated in  FIG. 1 ; 
         FIG. 7   c  is a schematical view further illustrating how the engineered flex of the same wall allows the canister assembly receiving opening in the nozzle assembly to expand so that the replaceable stop may slip past the activator when the handle is forced down without first releasing the activator, thereby reducing wear and tear on the latch mechanism; and 
         FIG. 8  is a schematic view of an alternative embodiment of the invention. 
     
    
    
     Reference will now be made in detail to the present preferred embodiments of the invention, an example of which is illustrated in the accompanying drawing figures. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference is now made to  FIG. 1 , which illustrates the upright vacuum cleaner  10  of the present invention. As illustrated, the vacuum cleaner  10  includes a housing  12  including both a nozzle assembly  14  and a canister assembly  16 . The nozzle assembly  14  includes a suction inlet  18  through which air entrained with dirt and debris is drawn into the vacuum cleaner  10 . A rotary agitator  20  is mounted to the nozzle assembly  14  and extends across the suction inlet  18 . 
     The canister assembly  16  includes a handle  22  having a handgrip  24 . An actuator switch  26  is provided for turning the vacuum cleaner on and off. In addition the canister assembly  16  includes a cavity or receiver  28  for receiving and holding a dirt collection vessel  30  such as a filter bag or dirt cup. A suction generator  32  is mounted in a compartment in the canister assembly  16 . During operation, the rotary agitator  20  beats dirt and debris from the nap of the rug or carpet being cleaned. The suction generator  32  draws air entrained with that dirt and debris through the suction inlet  18  into the dirt collection vessel  30 . The dirt and debris is trapped in the dirt collection vessel  30  and the now relatively clean air passes through and over the motor of the suction generator  32  to provide cooling before being exhausted through an exhaust port  34  back into the environment. 
     It should be appreciated that the canister assembly  16  is pivotably connected to the nozzle assembly  14  about a first pivot axis P 1  by means of a trunnion mounting in a manner well known in the art. A latch mechanism, generally designated by reference numeral  40  functions to secure the canister assembly  16  in an upright or storage position relative to the nozzle assembly  14 , (note  FIG. 1 ). As illustrated in  FIG. 5 , the latch mechanism  40  generally includes an activator  42  having a first cam surface  44  and a pedal portion  46 . In the illustrated embodiment the activator  42  is pivotably mounted to the nozzle assembly  14  on a pivot pin  47  about a second pivot axis P 2  which is offset from the first pivot axis P 1  (see  FIGS. 6   a  and  6   b ). A spring  48  biases the activator  42  into a first position, which will be described in greater detail below. 
     The latch mechanism  40  also includes a replaceable stop  50  (see  FIG. 2 ). The replaceable stop  50  is made from a material selected from a group consisting of metal, die cast metal, powder metal, reinforced plastic, fiberglass filled nylon, reinforced polycarbonate and combinations thereof. As illustrated in  FIGS. 3 and 4  the replaceable stop  50  is secured in a receiver  52  provided on the canister assembly  16  by means of a fastener such as the screw  54 . A second stop  56  is provided on the canister assembly  16 . Both the replaceable stop  50  and the second stop  56  extend radially from the hub  58  that functions as the first pivot axis P 1  between the canister assembly  16  and nozzle assembly  14 . 
     As will become apparent from the following description, the replaceable stop  50  functions to lock or secure the canister assembly  14  in the upright storage position while the second stop  56  functions to limit the downward pivoting angle of the canister assembly  16  with respect to the nozzle assembly  14 . As oriented, the second stop  56  allows the canister assembly  16  to approach an approximately horizontal position with respect to the nozzle assembly  14  so as to allow an operator to use the vacuum cleaner  10  to clean under a bed, sofa or other furniture. As best illustrated in  FIG. 6   a , when in the upright storage position the spring  48  functions to bias the activator  42  so that the first cam surface  44  of the activator engages or meshes with the second cam surface  60  of the replaceable stop  50  thereby positively holding or securing the canister assembly in the upright storage position. 
     When the operator desires to release the canister assembly  14  and the operating handle  22  from the upright storage position in order to manipulate the vacuum cleaner to and fro across the floor, the operator engages the pedal portion  46 . Specifically, the pedal portion  46  of the activator  42  is depressed thereby pivoting the activator about the second pivot axis P 2 . This functions to disengage the first cam surface  44  of the activator  42  from the path of the second cam surface  60  of the replaceable stop  50  as the canister assembly  14  is pivoted about the first pivot axis P 1  with respect to the nozzle assembly  12  (see  FIG. 6   b ). The pedal portion  46  is then released and the canister assembly  14  pivots freely with respect to the nozzle assembly  12  between the replaceable stop  50  defining the upright storage position and the second stop  56  defining the maximum pivotable angle of the canister assembly with respect to the nozzle assembly. This allows the operator to freely manipulate the vacuum cleaner  10  during vacuum cleaner operation. When the operator desires to return the canister assembly  14  and handle  22  to the upright storage position, the operator simply pivots the handle forward. The cam surfaces  44  and  60  engage allowing the replaceable stop  50  to pass past the first cam surface  44  of the activator. The spring  48  then biases the activator into a closed position so that the activator is once again placed in position to secure the canister assembly  14  and handle  22  in the upright storage position. 
     In accordance with yet another aspect of the present invention, as illustrated in  FIGS. 7   a - 7   c  the nozzle assembly  12  and more specifically, at least one wall  68  of the nozzle assembly  12  defines an opening  70  having a width W that receives the canister assembly  14 . More specifically, the opening  70  is in the form of a channel having a bottom  70 A and two opposing sides  70 B and  70 C. During normal operation, when the handle/canister assembly  16  is in the upright or storage position (see  FIG. 1 ), the cam surface  60  of the replaceable stop  50  engages or meshes with the cam surface  44  on the actuator  42  (see  FIG. 7   b ). This serves to latch and positively hold the handle/canister assembly  16  in the storage position. Significantly, the wall  68  of the nozzle assembly  12  also includes an engineered flex wherein that opening or channel  70  expands to an opening of W+F to allow the replaceable stop  50  to pass the first cam surface  44  of the activator  42  when the canister assembly  12  is forced from the upright position without first disengaging the latch mechanism  40  (see  FIG. 7   c ). 
     For example, the opening may have a normal width W of approximately 240 mm and a flexed open width of W+F of approximately 247 mm (see  FIG. 7   a ). This structural arrangement ensures that the activator  42  and replaceable stop  50  of the latch mechanism  40  function as necessary to secure the canister assembly  14  in the upright storage position under all normal operating conditions. However, when an operator forgets to release the latch mechanism  40  before forcefully ripping the control handle  22  downwardly, the engineered flex ensures that the latch mechanism  40  and particularly the activator  42  and the replaceable stop  50  are protected from excessive wear and tear and are not damaged by such rough handling. This enhances the service life of the latch mechanism  40  and thereby increases the life span over which the vacuum cleaner may be operated and still properly lock with the handle/canister assembly  16  in the upright or storage position. 
     It should be appreciated that the engineered flex is a product of the resilient plastic material used to produce the wall  68  of the nozzle assembly  12 . No separate spring or other mechanical mechanism is required to produce the desired/necessary flex in the wall  68  to accommodate a breakover condition and protect the replaceable stop  50  and activator  42  from excessive wear. Thus, the added expense and reliability issues characteristic of springs and other separate mechanical mechanisms is avoided. 
     In summary, numerous benefits result from employing the concepts of the present invention. By making the replaceable stop  50  and at least the first cam surface  44  of the activator  42  from strong, low-wear materials, it is possible to significantly enhance the service life of the latch mechanism  40  well beyond that achievable when these structures are molded from standard, lightweight plastic housing materials as in prior art designs. Further, the stop  50  may be replaced if it ever becomes necessary for any reason whereas a stop that is molded as a part of the vacuum cleaner housing cannot. Still further, by engineering a desired flex into the housing of the nozzle assembly the integrity of the latch mechanism  40  is preserved even if the canister assembly is pushed down forcefully and the cam is overridden. Advantageously, the engineered flex is an integral physical characteristic of the wall  68  of the nozzle assembly  12  and not a product of any separate or independent mechanical mechanism such as a spring. This “springless” design is less expensive to produce and maintain. 
     The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen describes the best illustration of the principles of the invention and its practical application to thereby one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as is suited to the particular use contemplated. All such modifications and the variations are within the scope of the invention as determined by the appended claims and interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.