Patent Publication Number: US-8123098-B2

Title: Battery holder for a driving tool

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a driving tool equipped with a rechargeable battery pack as a power source, for example, a gas combustion type driving tool for driving nails. 
     2. Description of the Related Art 
     For instance, as a driving tool such as a nail driver, a gas combustion type driving tool, which strikes driven members by reciprocating a piston with gases exploded in a combustion chamber, has been proposed as well as a driving tool using compressed air as a driving source. In the case of this gas combustion type driving tool, a fan is provided in a combustion chamber in order to stir the gases supplied into the combustion chamber and air introduced from outside to the combustion chamber in an appropriate ratio or to accelerate evacuation from the combustion chamber after combustion (after striking driven members). This fan in the combustion chamber rotates with an electric motor as a drive source. This electric motor for driving the fun in the combustion chamber uses, for example, a rechargeable battery pack as a power source, and this battery pack is detachably attached in the vicinity of a handle portion of the driving tool. 
     In an electric driving tool equipped with a detachable battery pack for charging etc. as described above, various technologies have been proposed regarding a structure for attaching this battery pack to a tool main body side, as provided, for example, in Japanese Laid-Open Patent Publication No. 10-296660, Japanese Laid-Open Patent Publication No. 2004-1193, and Japanese Laid-Open Patent Publication No. 2003-297312. Most of these technologies in the art relate to an electric tool to which substantially fixed and comparatively small vibration is consecutively applied during the use of an electric drill and an electric screwdriver etc., and special measures for the battery pack against the vibration are not required. Further, in Japanese Laid-Open Patent Publication No. 2004-1193, a technology is described regarding a gas combustion type driving tool in which a large vibration or impact is applied to the main body as a force of reaction each time a striking movement is made (intermittently). 
     However, the technology described in Japanese Laid-Open Patent Publication No. 2004-1193 is to prevent an electric contact failure against terminal blocks of the battery pack, which is caused by the vibration etc. occurred each time a striking movement is made to the tool body. Therefore, it is required to reliably prevent other failures (for example, falling of the battery pack etc.) caused by the vibration etc. 
     Thus, there is a need in the art to prevent various failures predicted to occur by a large vibration or impact caused each time a striking movement is made in a driving tool equipped with a detachable battery pack as a power source such as a gas combustion type nail driver etc. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, a battery pack is attached to a battery holder supported in a floating state with regard to the tool main body via an elastic material, electrically connected via this battery holder with regard to the tool main body, and attached so that the battery pack may not fall off. And thus, the vibration or the impact as a force of reaction caused by a striking movement at the tool main body side is absorbed by the elastic material, and transmission of the vibration or impact to the battery holder is greatly restricted. As a result, an electrical contact and an attaching state of the battery pack with respect to the battery holder can be maintained satisfactorily. 
     According to a second aspect of the invention, the battery holder can be supported in a floating state with regard to the tool main body in a simple and an inexpensive configuration. 
     According to a third aspect of the invention a nail feed direction is configured in a cross direction with regard to a striking direction of the driving tool, and an attaching direction of the battery pack is configured along this nail feed direction. And thus, the battery pack slides in the cross direction with regard to the striking direction of driven members, and is attached to and detached from the battery holder. As a result, only a part of the vibration and impact caused by the striking movement may act in the detaching direction of the battery pack. In this respect, the vibration or the impact transmitted to the battery pack can be further reduced, whereby it is ensured that an electric contact failure of the battery pack can be reliably reduced and unintended falling out of the battery of the battery pack can be prevented. 
     According to another aspect of the invention, even if the tool main body falls off accidentally, the battery pack can be prevented from directly hitting a floor etc., and thus damage to battery pack can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a general side view of a driving tool according to an embodiment of the present invention and a gas combustion type driving tool for driving nails. This figure shows a state in which the tool is equipped with a battery pack. 
         FIG. 2  is a side view of a rear end portion side of a driven-members-housing magazine, and shows a state in which a battery holder is exposed by fracture of a part of the rear end portion. 
         FIG. 3  is a lateral cross-sectional view of the driven-members-housing magazine and the battery holder, and shows a state in which an attached battery pack is exposed. 
         FIG. 4  is a view taken along the line indicated by arrows ( 4 )-( 4 ) of  FIG.3  and a longitudinal cross-sectional view of the driven-members-housing magazine and the battery holder along a feed direction of driven members. This figure shows a state in which the attached battery pack is exposed. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Next, an embodiment of the present invention will be described with reference to  FIG. 1  to  FIG. 4 . In this embodiment, a gas combustion type nail driver is illustrated as an example of a driving tool.  FIG. 1  shows an overall driving tool  1  according to this embodiment. This driving tool  1  includes a tool main body  10 , a handle portion  30  provided in a state in which it protrudes laterally from the lateral part of the tool main body  10 , and a driven-members-housing magazine  40  provided to extend between a distal end portion of the tool main body  10  and a distal end portion of the handle portion  30 . A battery pack  51  is attached to the distal end portion of this driven-members-housing magazine  40  (a rear end portion with respect to a feed direction of driven members, a lower end portion in  FIG. 1 ). The embodiment is characterized in the attachment configuration of this battery pack  51 , and a basic configuration of the driving tool  1  such as the tool main body  10  requires no particular changes. A brief explanation will be described below. 
     The tool main body  10  is provided with a cylinder  12  and a piston  13  in a tubular main body case  11 . In the center of the piston  13 , a striking driver  14  is mounted. This driver  14  is elongated forward in a striking direction, and the distal end portion is directed into a striking driver guide  15  in which a driven member is fed one by one. The driver guide  15  is provided in a state in which the driver guide  15  protrudes from a lower part of the tool main body  10 . A driven member is struck by this driver  14  and driven out of the distal end of the driver guide  15 . 
     At a rear portion of the tool main body  10  (an left end portion in  FIG. 1 ) and an upper face side of the piston  13 , a combustion chamber  16  is provided. This combustion chamber  16  is opened and closed by a tubular chamber  17  that moves along the striking direction. 
     In the combustion chamber  16 , a stirring fan  18  is mounted. This fan  18  rotates with a fan motor  19 . Further, though not seen in  FIG.1 , an ignition plug is mounted in the combustion chamber  16 . Power to this ignition plug and the above fan motor  19  is supplied by the above battery pack  51 . 
     Further, though omitted in the figure, a cassette gas cylinder filled with combustion gases for supplying in the combustion chamber  16  is housed in the tool main body  10 . Combustion gases for one-time combustion that are supplied from this gas cylinder to the combustion chamber  16  are stirred and mixed with air in an appropriate mixing ratio by the rotation of the fan  18 , whereafter when the ignition plug is ignited, the combustion gases explode and the piston  13  moves downward. When the piston  13  moves downward, one driven member fed to the driver guide  15  is struck by the driver  14 , which drives the driven member out of the distal end of the driver guide  15 . 
     In the driver guide  15 , a contact lever  20  is provided such that it can be moved along a striking direction. This contact lever  20  is maintained at a position where it protrudes from the distal end of the driver guide  15  by a given size. When the distal end portion (striking exit) of the driver guide  15  is pressed against a driven material to move the contact lever  20  relatively upward (on), the chamber  18  is closed so that combustion gases are supplied into the combustion chamber  16  and the fan  18  starts to rotate. 
     At a base portion of the handle portion  30 , a trigger-type switch lever  31  is provided. When this switch lever  31  is pulled with a fingertip in a state in which the above contact lever  20  is turned on, the ignition plug is ignited, whereby a driving operation is performed once by combustion (explosion) of the combustion gases. 
     The cylinder  12 , the piston  13 , the driver  14 , the driver guide  15 , and the combustion chamber  16  etc. may serve as a driving mechanism for striking driven members, and these components include a striking mechanism. 
     The driven-members-housing magazine  40  functions to load thin-sheet-shaped connected members that connect a number of driven members in parallel, to pitch and feed these connected members in a feed direction (toward the driver guide  15  side) in association with a driving movement of the tool main body  10  side, and thereby to feed driven members one by one into the driver guide  15 . 
     At a lateral lowered side of this driven-members-housing magazine  40  in the striking direction of the driven members, a battery attachment section  50  for attaching a battery pack  51  is provided. The detail of this battery attachment section  50  is shown in  FIG. 2  and its subsequent figures. As shown in  FIG. 4 , a lower part of a magazine case  41  of the driven-members-housing magazine  40  has a shape that is slightly swollen laterally, and a battery holder  52  is supported within the swollen portion  41   a . The magazine case  41  has a so-called two-piece structure. By use of this two-piece structure, the battery holder  52  is mounted and supported at a lower part of the magazine case  41 . 
     The battery holder  52  has a substantially tubular shape, and in its outer circumferential side two elongated protrusions  52   a  and  52   b  are integrally formed along its entire circumference. Above the upper elongated protrusion  52   a  and below the lower elongated protrusion  52   b  in  FIG. 4 , rubber rings  53  and  54  are fitted respectively. In this specification, unless otherwise noted, an upper side means a forward side in a striking direction of driven members (toward the upper side in the figures) and a lower side means a backward side against the striking direction of driven members (toward the lower side in the figures). 
     On the other hand, two engaging projections  41   b  and  41   c  are formed integrally on the inner side of the swollen portion  41   a  of the magazine case  41 . The battery holder  52  is supported in the swollen portion  41   a  of the magazine case  41  in a state in which the upper rubber ring  53  is elastically interposed between the upper engaging projection  41   b  and the upper elongated protrusion  52   a , and the lower rubber ring  54  is elastically interposed between the lower engaging projection  41   c  and the lower elongated protrusion  52   b . Two elongated protrusions  52   a  and  52   b  are not in contact with the magazine case  41  side. Further, other portions of the battery holder  52  do not hold in contact with or are not in contact with the magazine case  41 , either. The battery holder  52  is supported in a floating state in the swollen portion  41   a  of the magazine case  41  in a state in which only two rubber rings  53 ,  54  are in contact with the magazine case  41 . In this way, the battery holder  52  is supported in the magazine case  41  via only rubber rings  53  and  54 , which are elastic material, in a floating state, and thus the vibration or the impact (a force of reaction caused by a striking movement) occurred at the tool main body  10  side can be blocked and all of the vibration or the impact may not be transmitted to the battery holder  52 . As a result, the vibration etc. transmitted to the battery holder  52  can be greatly reduced. A battery pack  51  is attached to this battery holder  52  supported in a floating state. 
     As shown in  FIG. 3  and  FIG. 4 , a terminal block  55  is mounted in the rear part of the battery holder  52 . This terminal block  55  is electrically connected to a control circuit of the tool main body  10  via lead wires that is not shown. And thus, the battery pack  51  attached to the battery holder  52  is electrically connected to the control circuit of the tool main body  10  side via this terminal block  55 . 
     At both sides of a lowered portion of the battery pack  51  in an attaching direction, push buttons  51   a ,  51   a  for a removing operation are provided. The double push buttons  51   a,    51   a  are provided in a biased state in an opening direction respectively (toward a mutually separating direction). At the tip of the double push buttons  51   a ,  51   a , engaging claws  51   b  are integrally provided respectively. With an operation for attaching the battery pack  51  to the battery holder  52 , both of the engaging claws  51   b ,  51   b  are elastically engaged respectively with engaging concave portion  52   c ,  52   c  provided on the inner side of the opening of the battery holder  52 . And thus, the attaching state of the battery pack  51  with respect to the battery holder  52  is maintained. 
     In this attaching state, the battery pack  51  is attached in a state in which an end portion  51 E of the rear side of the battery pack  51  in the attaching direction is located such that the end portion  51 E may not protrude from an end portion  40 E of the driven-members-housing magazine  40 , as shown in the figure. 
     A push operation of the push buttons  51   a  with a fingertip can detach the engaging claws  51   b  from the engaging concave portion  52   c , and in this disengagement state the battery pack  51  can be pulled off and removed from the battery holder  52 . 
     According to the driving tool in the embodiment as constructed thus far, the battery pack  51  is attached to the terminal blocks of the driven-members-housing magazine  40  via the battery holder  52 . 
     The battery holder  52  is supported in a floating state (elastically supported) with respect to the magazine case  41  in a state in which the battery holder  52  is elastically in contact with only the rubber rings  53 ,  54  by elastically pressing and interposing the two rubber rings  53 ,  54 , which are fitted to the outer circumference of the battery holder  52  between the elongated protrusions  52   a ,  52   b  and the engaging projections  41   b ,  41   c  of the magazine case  41  side. As a result, the vibration or the impact caused by the drive movement of the tool main body  10  can be blocked with both the rubber rings  53 ,  54 , and the transmission of the vibration or the impact to the battery holder  52 , and eventually to the battery pack  51 , can be greatly reduced. 
     Since the vibration or the impact transmitted to the battery pack  51  can be greatly reduced in this way, an electrically contact state and an attaching state with respect to the tool main body  10  side of the battery pack  51  can be maintained in a good condition, and thus a failure such as adhesion or chattering of electric contacts can be prevented (protection of electrical contacts), and an unintended falling of the battery pack  51  can be prevented (protection of the battery pack itself). 
     Further, according to the driving tool  1  in the embodiment, the configuration is such that the battery pack  51  is attached in the rear end portion of the driven-members-housing magazine  40  and in a far-away portion from a driving axis of the tool main body  10 . In this respect, the battery pack  51  is not subject to the influence of the vibration or the impact of the tool main body  10  side. 
     Further, according to the driving tool  1  in the embodiment, the attaching direction of the battery pack  51  with respect to the battery holder  52  corresponds with the feed direction of the driven-members-housing magazine  40 , and thus the attaching direction of the battery pack  51  is configured in a cross direction with respect to the striking direction of the tool main body  10  (toward a moving direction of the driver  14 ). For this reason, a part of the vibration or the impact in the striking direction caused by the strike of the driver  14  with respect to driven members may act in the attaching direction of the battery pack  51 . In this respect, the battery pack  51  is not subject to the influence of the vibration or the impact that causes a failure such as chattering of electric contacts or an unintended falling by the disconnection from the engaging claws  51   b.    
     Further, according to the driving tool  1  as exemplified, the battery pack  51  is attached in a state in which the rear end portion  51 E of the battery pack  51  does not protrude from the rear end portion  40 E of the driven-members-housing magazine  40 . For this reason, in case that a user unintentionally drops the driving tool  1 , the rear end portion  40 E of the magazine  40  may hit a floor etc. but the battery pack  51  can be prevented from directly hitting a floor, and thus damage of the battery pack  51  can be prevented. 
     Various modifications can be made to the embodiment described above. For example, a configuration is exemplified in which the battery pack  51  is supported in a floating state via two rubber rings  53 ,  54 , but three rubber rings or more may be used as elastic members. Further, by using other elastic materials in place of rubber rings such as a compression coil spring, a tension spring, or a leaf spring, a similar function effect can be obtained. Further, by using screws with rubber bushings, the battery holder may be supported in a floating state. The key is to interpose elastic materials between the battery holder and the tool main body  10  side without rigidly connecting the battery holder and the tool main body  10  and to support the battery holder in the tool main body  10  side in a floating state in which the vibration or the impact may be blocked, and thus a similar function effect can be obtained. 
     Further, a gas combustion type nail driver is exemplified as an example of driving tools, but the embodiment can also be applied to driving tools in which a battery pack, which can be removed for charging or can be detached and exchanged, may be used as a power source for an electric motor or other electric appliances.