Abstract:
A suction device that is used with a power drilling tool for aspirating material removable during operation of the drilling tool, and which includes a suction head ( 20 ) displaceable relative to the drilling tool ( 2 ) in a direction opposite a drilling direction (B) of the drilling tool ( 2 ), and an aeration device ( 22 ) fixedly connected by a suction conduit with the suction head ( 20 ) for joint displacement therewith.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a suction device which is used with a power drilling tool for aspirating material removable during operation of the drilling tool such as drilling dust and drillings and which includes a suction head having a suction opening and displaceable relative to the drilling tool in a direction opposite a drilling direction of the drilling tool, an aeration device for producing a suction air current, and a suction conduit for connecting the suction head with the aeration device. 
   2. Description of the Prior Art 
   The advantage of the suction devices of the type described above consists in that a suction nozzle, which forms part of the suction head and is displaceably supported on the drilling tool, is displaced during the drilling process, in the direction opposite the drilling direction by the same amount the drill penetrates into the drilled surface. As a result of the displacement of the suction nozzle, it is always retained at the drill opening, which permits the removal of a relatively large amount of the drilling dust and drillings. The displacement of the suction nozzle relative to the drilling tool is effected by placing the nozzle against the drilling surface, with the nozzle being displaced by the counter-pressure of the surface which is applied to the suction nozzle as the drill advances. 
   U.S. Pat. No. 5,090,499 discloses a suction device releaseably connectable with a drilling tool. This suction device has an auxiliary handle on which all of the components of the suction device are supported and which can be clamped on the cylindrical receiving surface of the tool to which a conventional auxiliary handle is usually clamped. In order to be able to displace the suction head relative to the drilling tool in the direction opposite the drilling direction during operation of the tool, the suction head is displaceably supported by a rigid section of the suction conduit on the auxiliary handle and is connected with the aeration device by a flexible, bent section of the conduit. The suction conduit is connected at the end of the flexible section remote from the nozzle by the aeration device with a connector of a collection device which is likewise provided on the auxiliary handle. 
   The drawback of the known suction device is that the suction path between the suction nozzle and the collection device is relatively long because of the flexible bent section of the suction conduit. This leads to relatively high flow losses and a resulting reduction of the suction capacity. Moreover, the drawback of the flexible, bent section of the suction conduit consists in that, on the one hand, flow characteristics change during the drilling operation and, on the other hand, disturbances in the operation of the suction device can occur because of possible bending of the flexible section during operation. 
   Accordingly, one object of the present invention is to provide a suction device of a type described above in which the drawbacks of the known suction device are eliminated. 
   Another object of the invention is to provide a suction device of a type described above and having a high suction capacity. 
   SUMMARY OF THE INVENTION 
   These and other objects of the present invention, which will become apparent hereinafter, are achieved by fixedly connecting the aeration device with the suction head for joint displacement therewith in the same direction and by the same amount. 
   With the aeration device displacing together with the suction head in the same direction and by the same amount, the flow characteristics remain substantially constant during the drilling process. As a result, the suction device can be optimally adapted to the envisaged operation to achieve a maximal suction performance. 
   Advantageously, the suction conduit between the suction head and the aeration device is formed by a rigid suction pipe. “Rigid” here means that the suction pipe is essentially deformation free, i.e., is inflexible. In this way, the aeration device is retained in the same position relative to the suction head during the displacement of the suction head relative to the drilling tool. 
   Preferably, during the operation of the suction device, the suction head and the aeration device are supported by a common guide for displacement relative to the drilling tool, which insures a simultaneous displacement of both components relative to the drilling tool. 
   According to a particularly advantageous embodiment of the present invention, the guide is releaseably mounted on the drilling tool, which permits the use of the suction device with different drilling tools. 
   Advantageously, the aeration device is connectable with the power supply of the drilling tool, which eliminates the need for a separate power supply for the suction device. By connecting the aeration device with the power supply of the tool the device is used with, weight and costs are reduced. 
   Alternatively, the actuation device can have a separate, accumulator-driven motor. In this way, a completely independently operating suction device is obtained, which may be used with a very large number of different tools. 
   Preferably, the suction pipe has a receiving chamber for a filter element, so that the material, which is produced during drilling consisting of drilling dust and drillings, can be produced relatively close to the suction nozzle. Thereby, the suction path can be noticeably reduced, which increases the suction capacity. 
   It is advantageous when the receiving chamber extends over almost the entire length of the suction pipe. This permits the use of a particularly long filter element with a correspondingly high filtering action. 
   The novel features of the present invention, which are considered characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment when read with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings show: 
       FIG. 1 . a plan view of the upper surface of a drill with a suction device according to the present invention; 
       FIG. 2 . a view similar to that of  FIG. 1 , but during a drilling process; and 
       FIG. 3 . a longitudinal cross-sectional view of the suction device in the position shown in  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A drilling tool  2 , which is shown in  FIG. 1 , includes a housing  4 , a drill  6 , and a cylindrical receiving region  8 . Instead of an auxiliary handle, which is normally secured to the receiving region  8 , a connection device  10  is releaseably secured to the cylindrical region. The attachment and release of the connection device  10  are effected with simple clamp means  12  of the connection device  10 . 
   A suction device  16  is displaceably supported for displacement in a displacement direction S relative to the drilling tool  2  on a rigid suction pipe  18  that extends through a guide opening  14  of the connection device  10 . The displacement direction S is substantially parallel to a drilling direction B of the drilling tool  2 . The suction pipe  18  performs a double function. On the one hand, it serves as a stable guide for the suction device  16  and, on the other hand, it serves as a suction conduit for connecting the suction head  20  with an aeration device  22 . The guide opening  14  functions as a common guide for both the suction head  20  and the aeration device  22  or for the entire suction device  16 . 
   The suction head  20  is provided on an end of the suction pipe  18  facing in the drilling direction B and has a suction nozzle  24  through which the drill  6  extends, as shown with dash lines. 
   The aeration device  22 , which is provided at the opposite end of the suction pipe  18  has, as shown with dash lines, a ventilator  28  which is driven by a motor  26 . The power supply of the motor  26  is effected from the power supply of the drilling tool  2  via a connection cable  30 . 
   As shown in  FIGS. 2-3 , instead of the power supply from the power supply of the drilling tool  2 , the aeration device  22  can be provided with an accumulator package  32  for supplying power to the motor  26 .  FIG. 2 , as discussed above, shows the drilling tool  2  during the drilling process. The drill  6  penetrated into a wall  34 . As a result of counter-pressure of the wall  34  on the suction head  20 , the suction device  16 , which includes the suction head  20 , the suction pipe  18 , and the aeration device  22  together with the accumulator package  32 , has been displaced rearwardly relative the drilling tool  2  in the direction opposite the drilling direction B. Because of a rigid connection of the suction head  20  with the aeration device  22  by the rigid suction pipe  18 , the distance between the suction head  20  and the aeration device  22  remains constant despite the displacement of the suction device  16 . As a result, the flow characteristics remain substantially constant. 
   As shown in  FIG. 3 , the suction pipe  18  has a receiving chamber  36  over substantially its entire length and in which a filter element  38  can be inserted. At its outer side, the filter element  38  has a filter region  40  and inside, the filter element  38  has a flow channel  42  opening toward the aeration device  22 . 
   As further shown in  FIG. 3 , the suction pipe  18  is positively connected with both the suction head  20  and the aeration device  22  by rapid-connection means in form of respective bayonet catches  44 . This permits to use the suction device  16  with suction pipes  18  having different lengths which, in turn, permits to use the suction device  16  with drilling tools having different lengths. 
   For using a suction device  16 , firstly, it is provided with a suction pipe  18 , the length of which permits to place the suction nozzle  24  of the suction head  20  on the free end of the drill  6  of the drilling tool  2  with which the suction device  16  is to be used. Before the suction device  16  is secured to the tool, a filter element  38  is placed or is already located in the receiving chamber  36  of the suction pipe  18 . Finally, the suction device  16  is secured on the receiving region  8  of the drilling tool  2  with the connection device  10  that includes the clamp means  12 . Then, the drilling tool  2  is placed on the wall  34  at a predetermined location. As soon as the drill  6  starts to penetrate into the wall  34 , the wall  34  applies pressure to the end surface of the suction head  20 , displacing the suction head  20  in the direction opposite the drilling direction B rearwardly relative to the drilling tool  2 . Because of the rigid connection of the aeration device  22  with the suction head  20  by the suction pipe  18 , the aeration device  22  is also displaced in the same direction and by the same amount as the suction head  20 . The displacement direction S of the suction device  16  remains parallel to the drilling direction B, with the suction pipe  16  functioning as guide means upon its displacement in the guide opening  14 . 
   During the drilling process, the ventilator  28 , which is driven by the motor  26 , generates a suction air current, the flow path  46  of which is indicated in  FIG. 3  with arrows. The suction air current provides for aspiration of the material, which is removed during the drilling process through the suction nozzle  24  and into the suction device  16 . The material is aspirated through the filter region  40  into the flow channel  42 , with the material, such as dust and drillings, being retained on the outer side of the filter region  40  in the receiving chamber  36 . The filtered air flows through the opening  48  into the aeration device  22  over the motor  26  and is removed outwardly out of the suction device  16  by the ventilator  28 . 
   In order to clean the receiving chamber  36  or replace the filter element  38 , the bayonet catch  44  between the suction head  20  and suction pipe  18  is released by a short pivotal and axial movement of the suction head  20  relative to the suction pipe  18 . Then, the filtered-out drillings can be removed from the receiving chamber  36 . 
   Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiment or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.