Abstract:
A suction cup dust extractor for a drill having a housing; a drill collar attached to the housing, having a drill passage formed through it; an aperture located on the housing through which air can be sucked out by a suction device; a recess formed by the walls of the housing having an opening which, in use, locates against a work piece to create a chamber; at least one first air passage formed within the housing which enables air to pass from the drill passage to the aperture; at least one second air passage formed within the housing which enables air to pass from the recess to the aperture; and a manually operable valve mechanism mounted in the housing which is connected to the recess and which, when operated, allows air surrounding the housing to freely enter the recess when its opening is located against a work piece; characterized in that the housing further comprises a hand grip), the valve mechanism being mounted, at least in part, inside of the hand grip.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority, under 35 U.S.C. §119(a)-(d), to UK Patent Application No. GB 09 218 61.1 filed Dec. 15, 2009, the contents thereof to be incorporated herein by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a dust extractor for use with a drill, hammer drill or hammer, and in particular to a suction cup dust extractor. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 4,205,728 and DE202008008561 both disclose a suction cup dust extractor for a drill. The present invention aims to provide an improvement in the design over those disclosed in U.S. Pat. No. 4,205,728 and DE202008008561. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, there is provided a suction cup dust extractor for a drill comprising: 
     a housing; 
     a drill collar attached to the housing, having a drill passage formed through it; 
     an aperture located on the housing through which air can be sucked out by a suction device; 
     a recess formed by the walls of the housing having an opening which, in use, locates against a work piece to create a chamber; 
     at least one first air passage formed within the housing which enables air to pass from the drill passage to the aperture; 
     at least one second air passage formed within the housing which enables air to pass from the recess to the aperture; and 
     a manually operable valve mechanism mounted in the housing which is connected to the recess and which, when operated, allows air surrounding the housing to freely enter the recess when its opening is located against a work piece; 
     characterized in that the housing further comprises a hand grip, the valve mechanism being mounted, at least in part, inside of the hand grip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the invention will now be described with reference to enclosed drawings of which: 
         FIG. 1  shows a perspective view of the top of the suction cup dust extractor according to the first embodiment of the present invention; 
         FIG. 2  shows a top view of the suction cup dust extractor; 
         FIG. 3  shows a bottom view of the suction cup dust extractor; 
         FIG. 4  shows a front view of the suction cup dust extractor; 
         FIG. 5  shows a vertical cross sectional view of the suction cup dust extractor in the direction of Arrows A in  FIG. 4 ; 
         FIG. 6  shows a perspective view of the underside of the suction cup dust extractor; and 
         FIG. 7  shows a horizontal cross sectional view of the suction cup dust extractor in the direction of Arrows C in  FIG. 4 . 
         FIG. 8  shows a perspective view of the top of the suction cup dust extractor according to the second embodiment of the present invention; 
         FIG. 9  shows a top view of the suction cup dust extractor; 
         FIG. 10  shows a bottom view of the suction cup dust extractor; 
         FIG. 11  shows a front view of the suction cup dust extractor; 
         FIG. 12  shows a vertical cross sectional view of the suction cup dust extractor in the direction of Arrows G in  FIG. 11 ; 
         FIG. 13  shows a horizontal cross sectional view of the suction cup dust extractor in the direction of Arrows H in  FIG. 11 ; 
         FIG. 14  shows a vertical cross sectional view of the suction cup dust extractor in the direction of Arrows I in  FIG. 12 ; and 
         FIG. 15  shows a close up view of the venture passages. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 to 7 , the first embodiment of the suction cup dust extract will now be described. 
     The suction cup dust extractor comprises a housing  10  and a drill collar  12  rigidly connected to it at the top end of the housing  10 . The housing  10  comprises a skirt  14  with a bridge  16  formed on top of the skirt  14 . The bridge  16  extends from the middle of the skirt  16  to the top end of the skirt  16  where it is attached to the side of the drill collar  12 . The bridge forms a hand grip by which an operator can hold the extractor using one hand, by placing the fingers of the hand on one side and the thumb on the other and squeezing the bridge to hold it. The skirt  14  has a top wall  50  and side walls  52  which define a large recess  38 , on the opposite side of the skirt  14  to that on which the bridge  16  is attached, which has an opening which faces away from the bridge  16 . 
     The drill collar  12  forms a drill passage  18  which enables a cutting tool, such as a drill bit (not shown), to pass through it (direction of Arrow B in  FIG. 5 ) to engage a work piece  20 . The drill collar  12  has a longitudinal axis  22 . Both the drill passage  18  and the opening of the recess  38  are orientated in the same direction. 
     Formed in end  26  of the bridge  16  in the middle of the skirt  14  is an aperture  24  which provides an air exit. The aperture  24  has a longitudinal axis  28  which is perpendicular to and intersects with the longitudinal axis  22  of the drill collar  12 . 
     Formed by an internal wall  30  of the housing  10  is a first passage  32  which extends from the aperture  24  towards the drill passage  18  of the drill collar  12 . The internal wall  30  also forms one of the walls which form the recess  38 . Formed within the first passage  32  is a throat  34  where the diameter of the passage  32  is reduced. Two apertures  36  are formed through the wall  30  of the passage  32  at the narrowest point of the throat  34 . The apertures  36  provide two passageways directly from the passage  32 , through the wall  30 , to the recess  38  formed by the skirt  14 . Such a construction provides the operator with easy access to the apertures  36  should they become blocked with debris as the apertures  36  are exposed to the recess which is easily accessible through the opening of the recess  38 . 
     Each of the two apertures  36  has a longitudinal axis  98 , which extends along the length of the passageway formed by the aperture  36 , and which intersects with the longitudinal axis  100  of the passage  32 , at the point where the apertures  36  and passage  32  meet, at an angle of between 40 and 50 degrees and ideally at 45 degrees ( 102 ). The longitudinal axes  98  extends into the passage  32  from the apertures  36 , in a direction parallel to the longitudinal axis  100  of the passage  32 , in the same direction as the flow of air as it is sucked from the drill passage  18  through the passage  32  (direction of Arrow J in  FIG. 5 ). 
     The passage  32  splits into two passages  60  between the throat  34  and the drill passage  18 , each connecting with the drill passage  18  through a separate aperture  62 . 
     An inlet air passage  64  is formed in by a frame  66  attached to the base of the drill collar  12  and operates in the same manner as that described in EP1457288. Air can pass through the inlet air passage into the drill collar  12  as shown by Arrow D. 
     A seal  40  locates in a groove  42  formed around the periphery of the wall of the skirt  20  on the underside of the skirt  14 . When the suction cup dust extractor is placed against a work piece  20 , it engages with the seal  40 , the work piece  20  sealing the opening to the recess  38  to form a chamber. 
     An air hole  68  is provided in the wall  50  of the skirt  20  to provide a small air passage between the recess and the surrounding atmosphere. During the use of the suction cup dust extractor, the hole  68  ensures that there is a limited but constant air flow in the recess formed under the skirt  20  if the seal provides a perfect air seal with the work piece  20 . 
     The suction cup extractor further comprises a tubular connection collar  2  which connects to a vacuum source (not shown). A rubber seal  4  is fastened inside of the connection collar  2  and which comprises two rubber rings  4  which extend radially inwards from the drill collar  12  with an aperture  8  formed through them. The rings  4  are capable of gripping onto the nozzle (not shown) of a hose (not shown) of the vacuum source. As the rings  4  are resilient, they can stretch radially outwardly, increasing the size of the apertures  8 , enabling nozzles of different sizes to be used. The rings  4  would then grip the nozzle due to their resilience and frictionally hold the nozzle. 
     The connection collar  2  connects to the aperture  24  via a flexible tube  72 . One end of the flexible tube  72  is held in a sleeve  74  formed in the connection collar  2 , the other in a sleeve  76  formed in the bridge  16 . The flexible tube  72  can be stretched to extend its length and move the collar  2  away from the housing  10  or be bent or twisted to allow the connection collar  2  to be moved to a range of positions relative to the aperture  24 . The flexible tube  72  is made from rubber. 
     In use, the suction cup dust extractor is placed against a surface  70  of the work piece  20  so that the seal  40  makes contact with it. A chamber is formed when opening of the recess  38 , formed by the walls  30 ,  50 ,  52 , of the skirt  14  is sealed by the surface  70  of the work piece  20 . The suction device is activated and air is sucked through the connection collar  2 , through the flexible tube  72 , through the aperture  24 , through the first passage  32 , through the pair of separate passages  60 , through the apertures  62  and then from the drill passage  18 . As air passes through the throat  34  of the first passage  32 , it speeds up, causing a reduced pressure inside of the two apertures  36  due to a venturi effect. This results in the air in the recess  38  to be sucked out through the apertures  36  and into the passage  32 . This causes the skirt  14  and hence the dust extractor, to be attached to the surface  70  due to the suction. The hole  68  ensures that there is a constant flow of air from the hole  68 , through the recess  38 , and then through the two apertures  36 . The operator can then drill a hole in the surface by passing the drill bit through the drill collar  12  and drilling into the surface  70 . Any debris generated during the drilling process will be sucked up into the drill passage  18  and then into passages  60 . The use of two passages provides better debris clearance. The debris is then transported through the passage  32 , through the aperture  24 , through the flexible tube  72  and then through the connection collar  2 . The hole  68  ensures that there is always air passing through the two aperture into the passage  32 , thus ensuring no debris passes into the apertures  36  or the recess  38 . Furthermore, the 45 degree angle between the apertures  36  and passage  32  further reduces the risks of any debris entering the apertures  36  as it sucked past the apertures  36  from the drill passage  18  to the aperture  24 . 
     A second embodiment of the present invention will now be described with reference to  FIGS. 8 to 14 . Where the same features are present in the second embodiment which are present in the first embodiment, the same reference numbers have been used. The design of the second embodiment is the same as that for the first embodiment except for the design of three features, namely, 1) the design of the seal  40  has been altered, 2) the provision of an additional aperture to the two apertures  36 , and 3) a new feature of a pressure release mechanism for the recess  38  has been added. 
     Firstly, the changes to the design of the seal will be described. 
     Referring to  FIGS. 10 ,  12 , and  14 , the opening  80  of the recess  38  is planar ie the periphery of the opening  80  locates in a flat plane  82 . The seal comprises a base  84  which locates in a groove  42  formed in the wall  52  of the skirt  14 . The base  84  of the seal is held within the grove  42  via cover  90  which is held in place on the housing using screws (not shown). A flange  86  is attached to the base  84  which extends from the base  84  in a direction which is an oblique or small angle  88  relative to the plane  82 . The flange  86  extends, in a direction parallel to the plane  82  (in the direction of Arrows M), away from the opening  80 . The flange  86  extends, in a direction perpendicular to the plane  82  (in the directions of Arrows N), away from the opening  80 . The outer perimeter of the flange  86  is supported by a secondary wall  92  formed on the shirt  14  of the housing  10 . 
     Secondly, the additional aperture  94  and its inter connection with the recess will now be described. 
     Referring to  FIGS. 12 ,  13  and  15 , in addition to the two apertures  36  formed through the wall of the passage  32  at the narrowest point of the throat  34  to provide two direct passageways from the passage  32  to the recess  38 , there is provided a third aperture  94 , located between the two apertures  36 , which is formed through the wall of passage  32  at the narrowest point  34  and which connects to an intermediary chamber  96  formed in the bridge  16 . The intermediary chamber  96  connects to the recess  38  so that air can freely move between the intermediary chamber  96  and the recess  38 . The outer wall of the intermediary chamber is formed by the external wall of the bridge  16 . 
     Each of the two apertures  36  has a longitudinal axis  98 , which extends along the length of the passageway formed by the aperture  36 , and which intersects with the longitudinal axis  100  of the passage  32 , at the point where the apertures  36  and passage  32  meet, at an angle of between 40 and 50 degrees and ideally at 45 degrees ( 102 ). The longitudinal axes  98  extend into the passage  32  from the apertures  36 , in a direction parallel to the longitudinal axis  100  of the passage  32 , in the same direction as the flow of air as it is sucked from the drill passage through the passage  32  (direction of Arrow J in  FIGS. 12 and 15 ). 
     The third aperture  94  has a longitudinal axis  104 , which extends along the length of the passageway formed by the aperture  94 , and which intersects with the longitudinal axis  100  of the passage  32 , at the point where the third aperture  94  and passage  32  meet, at an angle of between 40 and 50 degrees and ideally at 45 degrees  106 . The longitudinal axis  104  extends into the passage  32  from the aperture  94  in a direction parallel to the longitudinal axis  100  of the passage  32 , in the same direction as the flow of air as it is sucked from the drill passage through the passage  32  (direction of Arrow J in  FIGS. 12 and 15 . 
     The 45 degree angle between the apertures  36  and passage  32  reduces the risks of any debris entering the apertures  36  or third aperture as it sucked past the apertures  36 ,  94  from the drill passage  18  to the aperture  24 . 
     The addition of the third aperture provides for increased suction in the recess  38 . 
     Thirdly, the new feature of a pressure release mechanism for the recess  38  will now be described. 
     Formed in each side of the bridge  16  is a button aperture  110 . Located within each button aperture  110  is a button  112 . Each button  112  is mounted on an end  116  of a flexible plastic support  114  which extends around the inside of the outer wall  118  of the bridge  16  inside of the intermediary chamber  96 , wrapping around the top half of the passage  32  (see  FIG. 14 ). A leaf spring  120 , which extends along the length of the plastic support  114 , is surrounded by the plastic support  114 , and also wraps around the top half of the passage  32 . The ends  122  of the leaf spring  120  directly engage behind the ends  116  of the plastic support behind the buttons  112 . The leaf spring  120  is resilient in nature and, if left in isolation would straighten up along its length. When located as shown in  FIG. 14 , the leaf spring  120  has been bent against its biasing force in order to be able to fit in the position as shown. The ends of the leaf spring  120  urge the ends  116  of the plastic support outwardly (in the direction of Arrow Q), urging the buttons  112  through the apertures  110 . 
     The edges of the ends  116  of the plastic support  114  engage with the edges  124  of the walls of the bridge  16  and skirt  14  housing  10 , due to the biasing force of the spring  120 , to seal the apertures  110 , thus preventing any air from escaping from the intermediary chamber  96  through the apertures  110 . 
     In use, the suction cup dust extractor is placed against a surface  70  of the work piece  20  so that the seal  40  makes contact with it. A chamber is formed when opening of the recess  38 , formed by the walls  30 ,  50 ,  52 , of the skirt  14  is sealed by the surface  70  of the work piece  20 . The suction device is activated and air is sucked through the connection collar  2 , through the flexible tube  72 , through the aperture  24 , through the first passage  32 , through the pair of separate passages  60 , through the apertures  62  and then from the drill passage  18 . As air passes through the throat  34  of the first passage  32 , it speeds up, causing a reduced pressure inside of the three apertures  36 ,  94  due to a venturi effect. This results in the air in the recess  38  to be sucked out either directly through the two apertures  36  or through the intermediary chamber  96  and the third aperture  94  and into the passage  32 . This causes the skirt  14  and hence the dust extractor, to be attached to the surface  70  due to the suction. During the normal operation, the buttons  112  are in their outer most position due to the biasing force of the leaf spring  120 , the edges of the ends of the plastic support engaging with the edges  124  of the of the walls of the bridge and skirt  14 . In order to release the suction cup extractor from the wall, the operator has two options. Firstly, the operation can switch of the vacuum device, reducing the pressure in the recess. Alternatively, the operator can depress the bottons  112 , moving the buttons  112  and the ends  116  of the plastic support  114 , against the biasing force of the leaf spring  120 , into the intermediary chamber  96 , breaking the seal formed between the edges of the ends  116  of the plastic support  114  and the edges  124  of the of the walls of the bridge  16  and skirt  14 , allowing air to be sucked in to the intermediary chamber from the air surrounding the extractor. This increases the pressure in the intermediary chamber  96  which, in turn, increases the pressure in the recess  38 . As such, the amount of suction created within the recess is reduced, allowing the operator to remove the extractor from the wall. 
     The use of two button constructed in this manner allows the operator to pinch the buttons  112  together to release the extractor whilst holding the bridge  16  in one hand by squeezing the bridge  16  between his fingers and thumb. 
     It will be appreciated by the reader that, as an alternative, the buttons  112  themselves can form a seal with the edges of the walls of the bridge  16  and skirt  14  instead of the ends  116  of the plastic support  114 .