Patent Publication Number: US-2011056047-A1

Title: Back carried work apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority of German patent application No. 10 2009 040 493.7, filed Sep. 8, 2009, the entire content of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a back carried work apparatus. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 7,774,896 discloses a back carried blower which has a blower tube arranged at the output of the blower spiral. The blower tube extends sideways and obliquely downwards away from the blower spiral. During operation, the blower tube is pivoted laterally, that is, to the left and to the right from the operator&#39;s perspective, as well as up and down. A bellows is provided in known back carried work apparatus to make this movement possible. To enable the lateral and the up and down pivot motions, the bellows section of the blower tube has to be comparatively long. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a back carried work apparatus of the kind described above, which has a simple configuration. 
     The back carried work apparatus of the invention includes: a back carrier having a back carrier plate extending in an up direction and a lateral direction when the back carrier is arranged on an operator&#39;s back; a drive motor arranged on the back carrier; a blower wheel defining a rotational axis extending transversely to the back plate; the drive motor being configured to rotatably drive the blower wheel about the rotational axis; a blower spiral having a blower output; a blower tube connected to the blower output and being mounted thereon so as to pivot about a pivot axis extending in the lateral direction of the back carrier plate; and, the blower wheel being configured to move air so as to cause an air flow through the blower spiral and through the blower tube. 
     Because the blower tube is pivotally mounted about a pivot axis which extends laterally, an upward/downward pivot motion can be performed via the pivot bearing of the blower tube. Thereby, an initial setting of the arrangement of the blower can be set via the pivot bearing of the blower tube. Thus, for example, a presetting according to the size of the operator can be made. During operation, small movements can advantageously be realized via a flexible section of the blower tube, for example, via a bellows section. Lateral movements can also be performed via this flexible section. As a result of the arrangement of the pivot bearing, the blower tube can be arranged upwardly for transport and advantageously projects about vertically upwards. Thereby, a space saving arrangement of the blower tube results for transport. If large pivot movements are required during operation, they can be partially or entirely made via the pivot bearing. It can also be provided that also small upward and downward movements during operation are made via the pivot bearing. 
     A simple embodiment is achieved when the blower tube is pivotally mounted on the blower output. The lateral orientation of the blower output can easily be achieved via a blower wheel with a rotational direction which is opposite to the rotational direction of common back carried work apparatus. For this purpose, the blower wheel rotates counterclockwise when viewed in a direction from the drive motor toward the back carrier plate. 
     Advantageously, the back carrier includes a base plate. The flow direction in the blower output thereby advantageously runs approximately parallel to the plane of the base plate, during operation especially approximately horizontal. In this way, a pivot motion of the blower tube in the vertical direction is made possible. In the transport state, the blower tube can thereby stand vertically upwards. An advantageous arrangement is achieved when the blower output is arranged immediately above the base plate in relation to the upward direction. This enables ergonomic working. 
     A simple embodiment is achieved when the blower tube includes a connector part which connects to the blower output and redirects the air flow. The flow direction in the inlet cross-section of the connector part and the flow direction of the output cross-section thereby conjointly define an angle between about 75° and 115° . An angle in the range of about 85° to about 105° has been shown to be especially advantageous. An angle (a) little larger than 90° has been shown to be advantageous. Thereby, the blower tube can be guided laterally around the operator in close proximity to the operator. The connector part is, in particular, pivotally mounted on the blower output. Advantageously, the connector part is rigid. The blower tube includes a bellows section to also allow for a lateral pivot movement of the blower tube. Advantageously, the connector part is formed integrally with the bellows section. In this way, the connector part can be made of a rigid material and be formed on the bellows section. The connector part can, however, also be flexible. The connector part can, however, also be a separate component. Advantageously, the bellows section is arranged downstream of the connector part. A bellows section, which redirects the air flow, can, however, also be connected to the blower output. 
     The proposed pivotal mounting of the blower tube is especially advantageous in the case of a work apparatus in which the blower inlet is arranged on the side of the blower wheel that faces toward the back carrier plate and is aligned axially to the rotational axis of the blower wheel. Accordingly, the blower wheel draws in in the axial direction and moves the air radially toward the outside and into the blower spiral. Advantageously, a plurality of intake openings are arranged between the back carrier plate and the blower spiral. In this area, the contamination of the ambient air through whirled-up dust particles or the like is low, so that few contaminants, which might clog or damage the intake openings, are drawn in. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described with reference to the drawings wherein: 
         FIG. 1  is a side elevation view of a blower apparatus carried on an operator&#39;s back; 
         FIG. 2  is a side elevation view of the blower apparatus of  FIG. 1  seen in the direction of the arrow II in  FIG. 1 ; 
         FIG. 3  is an enlarged view of the blower apparatus with the view from  FIG. 2 ; 
         FIG. 4  is a side view of the blower apparatus of  FIG. 3  seen in the direction of arrow IV from  FIG. 3 ; 
         FIG. 5  is a section view of a blower apparatus in the direction of arrow V-V from  FIG. 3 ; 
         FIG. 6  is a schematic side view of the connector part of the blower tube; and, 
         FIG. 7  is a side view of an alternate embodiment of a blower apparatus. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
       FIG. 1  shows a back carried blower  1  as an example embodiment of the back carried work apparatus. The blower  1  has a back carrier  2 , which is carried by an operator  14  shown schematically in  FIGS. 1 and 2  on the operator&#39;s back with two shoulder straps  3  and  4  ( FIG. 2 ). The back carrier  2  has a back carrier plate  15 , which rests on the back of the operator  14  with a cushion, which is not shown. The back carrier  2  also has a base plate  16  which extends transversely to the back carrier plate  15 , in particular, perpendicularly to the back carrier plate  15 . 
     A housing  5  is arranged on the back carrier  2 , in which a drive motor  8 , schematically shown in  FIG. 2 , is arranged. A start handle  6  for the drive motor  8  projects out of the housing  5 . A fuel tank  7  is arranged below the housing  5 . The fuel tank  7  can also be integrated in the housing. 
     The blower  1  has a blower tube  12 , through which work air is conveyed during operation. An operating handle  13 , with which the operator  14  can guide the blower tube  12  with his hand  20 , is fixed on the blower tube  12 . The blower tube  12  includes a connector part  24  which is pivotally mounted about a pivot axis  25 . Thereby, the entire blower tube  12  can be pivoted up and down in the direction of the double arrow  38 . A bellows section  30  is provided downstream of the connector part  24 . The bellows section  30  enables lateral movements and an up and down pivot motion of the operating handle  13  and thereby of the output opening  39  provided downstream of the blower tube  12 . The pivot movement of the blower tube  12 , which results from the pivotal arrangement of the connector part  24 , advantageously serves to enable a preset position of the blower tube  12  corresponding to the size of the operator. The pivot motion about the pivot axis further makes it possible to set the blower tube  12  upwardly for transport, so that the blower tube advantageously projects vertically. Thereby, a space saving transport is possible. During operation small lateral as well as small up and down movements can be made as a result of elastic deformation of the bellows section  30 . Very large pivot movements up and down in the direction of the double arrow  38  can be made possible by the bellows section  30 ; large movements can, however, also be performed by pivoting the connector part  24 . 
     The connector part  24  can be formed as a separate component which is connected to the bellows section  30  and to the housing  5  of the blower  1 . The connector part  24  can, however, also be integral with the bellows section  30 . In the embodiment shown the connector part  24  has smooth walls. The connector part is thereby rigid. The connector part  24  can, however, also be made of a flexible material. In the arrangement shown in  FIGS. 1 and 2 , the connector part  24  can also be formed integrally with the bellows section  30 , for example, molded onto the bellows section  30 . 
     As  FIGS. 1 and 2  show, the back carrier plate  15  extends in an upward direction  21  which is advantageously vertical as well as in a lateral direction  41 , which is in the lateral direction of the operator  14  and perpendicular to the upward direction  21 , when the back carrier  2  is arranged on the back of the operator  14 . The back carrier plate  15  thus extends about parallel to the back of the operator  14 . The base  19  of the base plate  16  extends about perpendicularly to the back carrier plate  15  and advantageously in the direction of a horizontal line H. The horizontal line H defines a horizontal plane when the operator stands upright. The lateral direction  41  is parallel to this plane. As  FIG. 2  shows, the pivot axis  25  extends in the lateral direction  41  and parallel to the horizontal line H. 
     The fuel tank  7  is arranged between the housing  5  and the base plate  16  in relation to the upward direction  21 . A suction head  18 , which conveys fuel to the drive motor  8 , is arranged in the fuel tank  7 . The drive motor  8  is configured as a single-cylinder combustion engine. As  FIG. 2  shows, the back carrier  2  has a handle  17  on the back carrier plate  15  with which the back carrier  2  can be carried. 
     A blower wheel  9  is arranged in the housing  5  as is shown schematically in  FIG. 3 . The blower wheel  9  rotates about a rotational axis  11  in a direction of rotation  22 . The rotational axis  11  is perpendicular to the plane  35  defined by the back plate  15  and shown in  FIG. 4 . The plane  35  thus extends in the upward direction  21  and the lateral direction  41 . The blower wheel  9  conveys the work air into a blower spiral  10  which extends along the periphery of the blower wheel  9 . The blower spiral  10  thereby enlarges in the rotational direction. The blower output  23  from the blower spiral  10  is to the side of the base plate  16  and immediately above the base plate  16 . 
     As  FIG. 3  shows, the connector part  24  is arranged on the blower output  23 . The connector part  24  is thereby held on the blower output  23  pivotally about the pivot axis  25 . The connector part  24  is advantageously rigid, especially made of plastic. The connector part  24  can, however, also be made at least partially of an elastic material. The connector part  24  is advantageously detachably mounted on the blower output  23 , for example, clipped into the blower spiral  10 , so that the blower tube  12  can be removed for transport. The blower tube  12  can, however, also project vertically upwards for transport. The base plate  16  extends in a plane  37 , which is advantageously about parallel to the horizontal line H during operation. The plane  37  is advantageously perpendicular to the plane  35  of the back carrier plate  15 . 
       FIG. 4  shows the arrangement of the blower output  23  in the horizontal direction between the fuel tank  7  and the back carrier plate  15 . A plurality of intake openings  36  for work air are provided between the housing  5  and the back carrier plate  15 . As  FIGS. 3 and 4  show, the connector part  24  is angled. The flow direction  34  in the output cross section  32  of the connector part  24  is oriented diagonally toward the front in the position of the blower tube  12  shown in  FIG. 1 . 
       FIG. 5  shows the setup of an embodiment of a blower  1  in detail. Thereby, the identical reference characters correspond to the same elements. The blower  1  has a start arrangement  28  for the drive motor  8 . The start arrangement  28  is actuated by the operator  14  via the start handle  6 . The drive motor  8  has a crankshaft  26  which is driven by the start arrangement during starting. A fan wheel  27  for moving cooling air for the drive motor  8  can be arranged between the crankshaft  26  and the start arrangement  28 . 
     The blower wheel  9  is arranged on the end of the crankshaft  26  which is opposite to the start arrangement  28 . The blower wheel  9  draws in work air via a blower inlet  29  in axial direction to the rotational axis  11 . The blower inlet  29  is arranged between the blower wheel  9  and the back carrier plate  15  in the direction of the rotational axis  11 . The blower spiral extends radially outside of the blower wheel. A plurality of intake openings  36  are arranged between the blower spiral  10  and the back carrier plate  15 , via which ambient air is drawn in and conveyed into the blower spiral  10  by the blower wheel  9  configured as a radial blower. 
       FIG. 6  shows an embodiment of the connector part  24 . The connector part  24  has an intake cross-section  31  which connects to the blower output  23 . The flow direction in the intake cross-section  31  corresponds to the flow direction  33  in the blower output  23 . The connector part  24  is formed in the shape of an arc of a circle and has an output cross-section  32  through which the work air flows in a flow direction  34 . The connector part  24  redirects the air flow conveyed by the blower wheel  9 . The flow direction  33  in the intake cross-section  31  and the flow direction  34  in the output cross-section  32  conjointly define an angle (a) which advantageously is between about 75° and about 115° , and in particular between about 85° and about 105° . It has been shown that an angle (a) of a little larger than 90° is especially advantageous. 
     Because of the pivotal arrangement of the entire blower tube  12  on the blower output  23  which is fixed to the housing, the blower tube  12  can be pivoted in the direction of the double arrow  38  ( FIG. 1 ) via the pivot bearing of the connector part  24 , so that an advantageous transport position results and a presetting of the position of the blower tube, for example to correspond to the size of the operator, is possible. The pivot bearing can also have a lock-in position in the vertically upwards position of the blower tube, so that the blower tube  12  can lock-in fixed in a transport position. This is simply achieved via the horizontal orientation of the blower output  23 , which is especially made possible by the reversal of the blower rotation direction  22 . Thereby, a simple configuration of the blower  1  results. 
       FIG. 7  shows an alternative embodiment of the blower, in which a bellows section  40 , which redirects the air flow, connects to the blower output  23 . The bellows section  40  is directly connected to the blower output  23  and is pivotal hereon about the pivot axis  25 . As a result of the pivotal arrangement of the bellows section  40  on the blower output  23  the presetting of the position of the blower tube  12  according to the size of the operator can be achieved, so that comparatively few deformations of the bellows section  40  must occur during operation. For transport, the bellows section  40  can be twisted on the blower output  23 , so that the blower tube  12  projects into a desired direction for space saving transport. The bellows section  40  is connected downstream with a rigid section of the blower tube  12  on which the handle  13  is also fixed. 
     It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.