Patent Publication Number: US-7594295-B2

Title: Auxiliary vacuum unit for a central vacuum cleaning system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Benefit of U.S. Provisional Application for Patent Ser. No. 60/975,856, filed on Sep. 28, 2007, is hereby claimed. 

   FIELD OF THE INVENTION 
   The present invention relates in general to a central vacuum cleaning system and more particularly to an auxiliary unit for attachment to the central vacuum cleaning system. 
   BACKGROUND OF THE INVENTION 
   Central vacuum cleaning systems are well known and are to be found in domestic and commercial premises to provide a centralized cleaning regime based on the vacuum cleaner principle to minimize the carriage of conventional equipment from place to place. Naturally, there are available small portable vacuum cleaners operable independently of the central vacuum system, which may easily be transported manually from location to location within domestic or commercial premises, but generally their power is restricted by the need to afford portability. 
   It is normal in a central vacuum cleaning system, for example as deployed in a condominium, to site a few strategically placed connection stations, coupled in a circuit to a central vacuum generating unit, and to provide a flexible hose of not inconsiderable length for registration with one station enabling cleaning of a number of rooms and areas to be achieved with that one length of hose. The length of the hose makes laborious the task of vacuuming in view of the need to carry such an unwieldy and relatively heavy mass of hose between stations. 
   Various proposals to alleviate this problem have been made. For example, US Patent Application Publication No. US 2007/0256269 to Pagni discloses a location specific unit integral with the fabric of the building in which it is to be employed, namely within the wall structure. However, this proposal merely provides a vacuum system for each cleaning area, rather than a central vacuum system with a number of outlets throughout the building. 
   Another example of prior art is to be found in US Patent Application Publication No. US 2008/0092323 to Smith et al who describe a central vacuum cleaning system as such with wall valves in the various rooms of a building structure and one cabinet housing cleaning tools including a flexible hose connected into the central system through a wall valve within the cabinet, which again is mounted within a stud wall. 
   There are other systems which provide for a similar arrangement as in the Smith et al proposal but with a free-standing cabinet, for example in a kitchen, housing an appropriate suction tool on a hose connected permanently to an inlet of the central vacuum cleaning system. Removal of the tool from a specially designed docking station, incorporating a switching arrangement, activates the vacuuming mode with replacement of the tool causing deactivation. A disadvantage of such a system is it always requires the opening of a cabinet door before reaching the cleaning tool, and the door remains open during operation of the system, which might be highly cumbersome. 
   Although the prior art suggests the need to make central vacuum cleaning systems more location specific to facilitate the cleaning operation, a disadvantage of the thereof is the requirement to include the facility within the structure of the building serviced by the central vacuum cleaning system. 
   Accordingly, there is a need for an auxiliary vacuum device for use with a central vacuum cleaning system. 
   SUMMARY OF THE INVENTION 
   It is therefore a general object of the present invention to provide an auxiliary vacuum device for use with a central vacuum cleaning system. 
   An advantage of the present invention is that the auxiliary vacuum device is location specific in relation to the central vacuum cleaning system, especially where cleaning/vacuuming is frequently required such as in the laundry room for the dryer filter, in the main entrance area, or even in close proximity to a pet litter box or the like. 
   A further advantage of the present invention is that the auxiliary vacuum device is mountable externally of the structure of the building in which the system is installed on a standard inlet mounting plate the same type used to install a conventional inlet valve. 
   A more specific advantage of the present invention is that such an auxiliary vacuum device incorporates a manageable length of flexible hose permanently associated with the system. 
   A still further advantage of the present invention is that the auxiliary vacuum device is so designed for quick, easy and safe usage, by having a standard sized tapered sealing component (docking station and probe), and by the fact that the standard sized probe is capable of receiving standard cleaning accessories for different cleaning tasks. 
   As other advantages of the present invention, when the probe of the auxiliary vacuum device is docked/sealed it allows other inlet stations to be used in the central vacuum cleaning system, and the switching mechanism is so designed as to avoid startup if the probe is installed in the docking station, thus protecting the central vacuum cleaning system motor from harmful overloading. The present unit is also automatically turned off as soon as the probe is inserted back into the docking station after usage. 
   Another advantage of the present invention is that the auxiliary vacuum device is that the unit includes an independent on/off switch for local operation and safety purposes. When the probe is removed from docking station the operator must manually press the on/off button to allow central vacuum cleaning system to start. Should the operator have to stop the central vacuum cleaning system for any reason he can do so by simply repressing the on/off button. 
   Yet another advantage of the present invention is that the auxiliary vacuum device is that the housing is so designed that the hose could be of various lengths and different types for example extruded or extruded electric hose with on/off switch, etc. The body upper edge can wind one turn of hose. The hose is removable from the device in order to be replaced or repaired. 
   According to the invention an auxiliary vacuum device for a central vacuum cleaning system for premises defining areas of occupancy, said system including an electrically powered vacuum generating unit, a system network of piping extending throughout the premises and terminating in at least one inlet formed in one of the walls defining at least some of the areas of occupancy, the device comprising a housing for registration with an inlet extending through a mounting plate of the system network, the housing being adapted for installation at the inlet mounting plate externally of the wall and being provided with an inlet port for communication with said inlet, a connection exterior to the housing, a pipe extending within the housing from the inlet port to said connection, a flexible concertina hose attached to the connection proximal to the housing, a cleaning tool mounting probe provided on the hose distal from the connection, a docking station in the housing for the cleaning tool mounting probe, and switch mechanism located within the housing and adapted for activating and de-activating the electrically powered vacuum generating unit of the central vacuum cleaning system. 
   The docking station of the housing serves as a friction type sealing component and is provided with a contact member forming part of the switch mechanism for interaction as between the cleaning tool mounting probe and another part of the switch mechanism whereby in use the removal of the probe initiates a first phase of the activation of the vacuum generating unit and re-insertion thereof causes de-activation of the unit. The contact member may conveniently be in the form of a cam provided on a pivotally mounted rocker arm. The rocker arm has formed therein a slot for receiving a stub shaft carried by a pivotally mounted guide arm. Both the rocker arm and the guide arm are pivotally mounted on a back plate of the housing and form part of the switch mechanism. 
   The auxiliary vacuum device is further characterized by the provision of an on/off button for depression in order to initiate a second phase of the activation of the vacuum generating unit or de-activate the vacuum generating unit of the central vacuum cleaning system. The on/off button includes a push rod. 
   The push rod itself carries a cam formation or contoured surface which selectively contacts the guide arm and causes said rotational movement. 
   A track, also forming part of the switch mechanism, is carried by another plate also pivotally mounted on the back plate and is resiliently biased with respect thereto, via a track torsion spring, in a direction allowing the follower pin to move along predetermined sections of the track toward the ‘off/standby’ position. 
   The rocker arm carries a follower pin engaging with the track which provides a tortuous path (formed by different sections) therefor, the movement of the pin within the track being occasioned by the interaction of track torsion spring, the rocker arm carrying the cam and the guide arm, which has an abutment for a torsion spring extending from an electrical contact on the back plate of the housing, then around the pivot of the guide arm and thence to the abutment whereby the guide arm is biased in an anti-clockwise direction. The torsion spring also constitutes an electrical path from the electrical contact to the guide arm and biases the guide arm in a direction toward enabling the torsion spring to get into contact with the other electrical contact. The interengagement of the stub shaft on the guide arm and the slot in the rocker arm and the bias of the torsion spring give the rocker arm and thus the pin thereon a bias in a clockwise sense. 
   The guide arm further comprises a contact recess allowing partial exposition of the torsion spring with which is engageable by another pole electrical contact mounted to the back plate of the housing. Suitable electrical power cables are provided for the electrical contacts mentioned supra. 
   The tortuous path provided by the track defines ‘off’, ‘off-standby’ and ‘on’ positions of the switch mechanism. The face of the track is contoured to ensure positive location of the pin in the various positions defined therein and to prevent any error in pin positioning within the track. 
   In use, removal of the cleaning tool mounting probe allows the pin to move along the track from the ‘off’ position and to snap into the ‘off/standby’ position under the influence of the torsion spring bias. Actuation of the on/off button rotates the guide arm and the rocker arm to allow the pin to travel from the ‘off/stand by’ position and to snap into the ‘on’ position with the electrical contact engaging the recess in the guide arm and allowing contact between the two terminals via the torsion spring to electrically close the circuit thus initiating the vacuum generating unit with suction being applied to the flexible hose, which may carry a suitable tool for the cleaning job in hand. The power may be interrupted by replacement of the cleaning tool mounting probe into the docking station thus causing the rocker arm to rotate anti-clockwise and to move the follower pin to the ‘off’ position, the contact opening away from the recess in the guide arm. In the alternative, the on/off button may again be depressed thus allowing the guide arm and the track to rotate clockwise thus causing the pin to slide within the track to the ‘off’ position. 
   Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, in which similar references used in different Figures denote similar components, wherein: 
       FIG. 1  is an isometric view of an auxiliary vacuum device in accordance with an embodiment of the present invention showing the device aligned for external mounting to a standard inlet mounting plate of a central vacuum cleaning system; 
       FIG. 2  is an enlarged partial perspective view of some details of the switch mechanism; 
       FIG. 2   a  is an exploded view of the details illustrated in  FIG. 2 ; 
       FIG. 3  is a partially broken internal view of the device showing the device in the ‘off’ position with the cleaning tool mounting probe in the docking station; 
       FIG. 4  is a partially broken schematic side view of the device shown in  FIG. 3  with some parts removed for the sake of clarity; 
       FIG. 5  is a partially broken internal view of the device of  FIG. 3  showing the device in the ‘off/standby’ position with the cleaning tool mounting probe removed from its docking station; 
       FIG. 6  is a partially broken schematic side view of the device shown in  FIG. 5  with some parts removed for the sake of clarity and with the on/off button having been depressed; 
       FIG. 7  is a partially broken internal view of the device of  FIG. 3  illustrating the device in the ‘on’ position following the depression of the on/off button as seen in  FIG. 6 ; 
       FIG. 8  is a partially broken schematic side view of the device shown in  FIG. 7  with some parts removed for the sake of clarity and showing the on/off button following further depression thereof; and 
       FIGS. 9   a  to  9   f  are schematic illustrations of the various phases of operation of the switch mechanism of the auxiliary vacuum device of the present invention showing the track and the position and displacements of the pin therewithin the corresponding phases. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the annexed drawings the preferred embodiment of the present invention will be herein described for indicative purpose and by no means as of limitation. 
   In  FIG. 1  there is illustrated an auxiliary vacuum device  1  which is mountable on a standard inlet mounting plate  5  which incorporates an inlet opening  2  of a central vacuum cleaning system (not shown) which incorporates an electrically powered vacuum generating unit the operation of which is controlled by the device in the manner hereinafter defined. Suitable low voltage electrical wires  3 ,  4  are provided and protrude from the standard inlet mounting plate  5  which is installed in a wall  6  of the premises in which the central vacuum cleaning system is installed. The device  1  comprises inter alia a housing  10  provided with an inlet port  12  for registration and flow communication with the standard inlet opening  2 , typically provided with a seal member such as an O-ring  7  or the like. The housing  10  encases a typically 90-degree elbow pipe  13  ( FIGS. 3 ,  5 , and  7 ) which interconnects the inlet port  12  with a connection  14  external to the housing  10  for a flexible concertina hose  16 . At the end of the hose  16  distal from the connection  14  is a cleaning tool mounting probe  18  which may be parked in a docking station  20  ( FIG. 3 ) formed in the housing  10 . An on/off push button  22  is provided on the housing  10  which itself is mounted to the wall  6  externally thereof and not integral with the standard inlet mounting plate  5 . 
     FIGS. 2 ,  2   a  show some of the mechanical details of the switch mechanism  23  encased within the housing  10 . A back plate  24  of the housing  10  is shown with two electrical low voltage terminals  26 ,  28  screw mounted to the plate  24  through which the wires  3 ,  4  are fed from the back via hole  25  and securely held by the screw mounts in conventional manner. The terminal  26  provides a contact point for a torsion spring  27 , whilst the terminal  28  provides a mount for a contact arm  29  having bent portion  29 ′. 
   A rocker arm  30  is pivotally mounted on the back plate  24  of the housing  10  and carries a cam  32  which protrudes into the docking station  20  of the cleaning tool mounting probe  18  as can more clearly be seen in  FIGS. 3 ,  5 , and  7 . An arm slot  33  is formed in the rocker arm  30  which also carries a follower pin  34  for engagement in a track  36  formed in the face of a track plate  38  which is pivoted at point  39  to the back plate  24  of the housing  10 . The floor  37  of the track  36  is contoured to some extent for a purpose hereinafter explained. 
   A guide arm  40  is pivotally mounted at  42  at one end thereof to the back plate  24  of the housing  10  and carries at its other end remote from pivot  42  a stub shaft  44  engageable with the rocker arm  30  at slot  33 . The pivot  42  of the arm  40  is received in an insulated bush mounting  43  (not required when the housing is molded out in a plastic material already an electrical insulator) around which the torsion spring  27  is reeved. The torsion spring  27  extends from the terminal  26  to contact an abutment  45  on the guide arm  40  which is provided with a recess  46  for exposing the torsion spring in register with, and receiving the bent portion  29 ′ of the contact arm  29  fixed to the terminal  28 . The assembled parts as shown in  FIG. 2  demonstrate that the torsion spring  27  biases the rocker arm  30  in a clockwise sense while the guide arm  40  is biased in the opposite sense (direction). 
   The track plate  38  located in a back plate recess  50  and pivoting at  39  is biased in relation thereto via a track torsion spring  39 ′, the plate  38  being biased in a counter clockwise sense. 
   As can more clearly be seen from  FIGS. 3 to 8  which are orthogonal views, the on/off push button  22  includes a swing cover  52  spring loaded as at  52 ′ and operable against a striker bar  53  connected to a push rod  54  suitably spring loaded as at  56  within a casing  57 . The push rod  54  is contoured on its lower surface  55  for selective contact with the guide arm  40  which is pivotal about the point  42 . 
   In operation, the auxiliary vacuum device is mounted externally on the wall  6  on the standard mounting plate  5  of a central vacuum cleaning system which provides a piping network (not shown) extending to strategic cleaning points throughout the premises. The system includes an electrically powered vacuum generating unit connected to the network and operable upon demand by the actuation of the device  1  which is location specific within the premises. For example in domestic premises where there is likely to be a heavy cleaning burden, e.g. the main entrance, laundry room or the garage, an inlet would be provided as would a device dedicated to that location. The length of the flexible concertina hose  16  may be of the order of up to 1.5 meters extensible to 6 meters, thus providing a local hose of manageable length for the location concerned. 
   In the non-operational mode of the central vacuum cleaning system, the probe  18  is placed firmly by frictional sealing contact, via a tapered of conical shape thereof within the docking station  20  ( FIG. 3 ) with the follower pin  34  within the track  36  at the ‘off’ position P 1  in  FIG. 9   a , as to provide a closed state of the pipe when not used, to allow proper functioning of the central vacuum cleaning system (via another standard mounting plate with is inlet valve located at any other location (not shown)) in the meantime. 
   When required for operation, the cleaning tool mounting probe  18  is removed from the docking station  20  thus releasing the rocker arm  30  which pivots in a clockwise direction as viewed in the figures under the action of the torsion spring  27  acting on the stub shaft  44  to move it along the slot  33  of the rocker arm  30 .  FIG. 5  shows the position of the rocker arm  30  following clearance of the probe  18  from the station  20 . The rotational movement of the rocker arm  30  causes the follower pin  34  to move along the primary section A of the track  36  to the ‘off/standby’ position P 2  along the arrow of  FIG. 9   b . The pin  34  remains at that position P 2  under the action of both the torsion spring  27  and the track torsion spring  39 ′ and because of the protrusion lip  35  formed by the shape of the track  36 . At this point if the probe  18  were to be re-introduced to the docking station, the rocker arm  30  would rotate anti-clockwise to bring the follower pin  34  along a return section X of the track back to the ‘off’ position shown at P 1  along the arrow of  FIG. 9 . The return section X of the track  36  is contoured outwardly of the track plate  38  to give a step ‘a’ adjacent P 1  whereby the pin  34  is locked in that position P 1  with respect to the section X. In other words the pin  34  can only pass along section X in a downwards direction to the ‘off’ position P 1 . 
   When it is desired to commence vacuuming, the push button  22  is depressed which causes the push rod  54  to move inwardly toward the plate  24  and have its lower surface  55  pushing on the guide arm  40  in a clockwise direction within the housing  10  about the pivot  42  and the rocker arm  30  in a anti-clockwise direction. Such movement allows the follower pin  34  to pass the lip  35  and flip into the secondary section B of the track  36  towards the ‘on’ position P 3  along the arrow of  FIG. 9   c . The section B of the track  36  is contoured outwardly toward the position P 3  to provide a step ‘b’ to ensure that once engaged at that position, reverse movement along the section B is prevented by the step so formed.  FIG. 7  illustrates the ‘on’ position and shows that the bent portion  29 ′ of the contact arm  29  is seated within the recess  46  on the guide arm  40  to contact the electrically conductive torsion spring  27  and electrically close the circuit between the terminals  26  and  28 , thus giving power to the vacuum generating unit of the central vacuum cleaning system. 
   Cessation of the vacuuming activity may be achieved by reinserting the probe  18  into the docking station  20  which causes the rocker arm  30  to rotate in an anti-clockwise direction and to take the pin  34  into the ‘off’ position&#39; at P 1  along the arrow of  FIG. 9   f  along a tertiary section C of the track  36 . The probe  18  is typically held within the docking station by friction. In the alternative, the re-depression of the push button  22  effects rotation of the guide arm  40  in a clockwise direction, and the rocker arm  30  in an anti-clockwise direction, and allows the follower pin  34  to pass partially along section C but then to pass into position P 2  under the action of the bias provided by the track torsion spring  39 ′ along primary section A to the ‘off/standby’ position along the arrow of  FIG. 9   d . Both actions cause the contact release of the bent portion  29 ′ of the contact arm  29  from the torsion spring  27  adjacent the recess  46  in the guide arm  40 , thus cutting off electrical power to the vacuum unit in the central system. 
   This dual possibility for cutting power is a valuable safety feature which can be triggered speedily when needed. 
   The externally mounted auxiliary device of the present invention thus presents a useful addition to a central vacuum cleaning system providing a location specific means of local cleaning without the need to have a station permanently mounted within the wall of the premises. Furthermore, the use of a relatively short length of flexible concertina hose makes the cleaning task less onerous than with the conventional systems employing hoses of considerable length and bulk making it unwieldy and time-consuming to operate. 
   It will be understood that the device may be deployed ab initio in the installation of a central vacuum cleaning system or may be retrofitted to an existing system with suitable modifications at the inlets thereof. 
   It will further be appreciated that the device per se may be enclosed within a cabinet in order to confer an aesthetic quality thereto. 
   Although the present invention has been described with a certain degree of particularity, it is to be understood that the disclosure has been made by way of example only and that the present invention is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope and spirit of the invention as hereinafter claimed.