Abstract:
A method of urging one or more fasteners toward a nosepiece of a fastening tool generally includes placing one or more fasteners into a magazine and moving a pusher block that is pivotally mounted on a pusher bearing toward the one or more fasteners. The method also includes rocking the pusher block about the pusher bearing as the one or more fasteners are fed sequentially into the nosepiece to maintain a pushing surface of the pusher block in substantial abutment with a surface of a last fastener of the one or more fasteners.

Description:
CROSS-REFERENCE TO A RELATED APPLICATION  
       [0001]     This application is a divisional of U.S. patent application Ser. No. 11/493,995 filed on Jul. 27, 2006. The disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD  
       [0002]     The present teachings relate to a fastening tool and more specifically relate to a pusher bearing and a pusher block in a magazine of the fastening tool that more uniformly distributes force on one or more fasteners in the magazine.  
       BACKGROUND  
       [0003]     A number of pneumatically and electrically operated tools have been developed to drive fasteners, such as staples and nails, into workpieces. Typically, these tools employ a magazine for holding a plurality of the fasteners and feeding the fasteners into a nose of the tool prior to driving the fasteners into the workpiece.  
         [0004]     Despite the widespread use of such tools, it is known that fasteners being fed through the magazine and into a driver blade channel formed in the nosepiece of the fastening tool can jam. In this regard, stack-up tolerances of all of the components of the magazine, plus imperfections in the fasteners, can contribute to the fasteners jamming in the magazine. While jammed fasteners can be readily evacuated from the magazine and the nose, there remains room in the art for improvement.  
       SUMMARY  
       [0005]     The various aspects of the present teachings generally include a method of urging one or more fasteners toward a nosepiece of a fastening tool. The method includes placing one or more fasteners into a magazine and moving a pusher block that is pivotally mounted on a pusher bearing toward the one or more fasteners. The method also includes rocking the pusher block about the pusher bearing as the one or more fasteners are fed sequentially into the nosepiece to maintain a pushing surface of the pusher block in substantial abutment with a surface of a last fastener of the one or more fasteners.  
         [0006]     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present teachings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present teachings in any way.  
         [0008]      FIG. 1  is a perspective view of a fastening tool constructed in accordance with the present teachings showing a nosepiece and a magazine in a closed position. The nosepiece is shown against a workpiece that places a contact trip mechanism in a retracted condition.  
         [0009]      FIG. 2  is similar to  FIG. 1  and shows the magazine in an open position and shows the nosepiece not engaged. With a tip of the nosepiece not engaged, the contact trip mechanism is in an extended condition and the fastening tool cannot be activated by a trigger assembly.  
         [0010]      FIG. 3  is similar to  FIG. 2  and shows the trigger assembly, a depth adjustment mechanism and a magazine clip.  
         [0011]      FIG. 4  is an exploded assembly view of the magazine of  FIG. 1  showing an outer case, an inner rail, a pusher block and a pusher bearing.  
         [0012]      FIG. 5  is a partial cross-sectional view of  FIG. 1  showing the pusher bearing, the pusher block and the fasteners in the magazine having the outer case illustrated as cut-away.  
         [0013]      FIG. 6  is a different partial cross-sectional view of  FIG. 1  showing a driver blade channel formed by an outer nose member and an inner nose member of the nosepiece. The inner nose is connected to the magazine, which is in the closed position.  
         [0014]      FIG. 7  is a diagram showing a pushing surface of the pusher block abutting a last fastener in a slightly upward direction because the pusher block is able to rock about the pusher bearing constructed in accordance with the present teachings.  
         [0015]      FIG. 8  is similar to  FIG. 7  and shows the pusher block in a slightly downward direction relative the pusher bearing constructed in accordance with the present teachings. 
     
    
     DETAILED DESCRIPTION  
       [0016]     The following description is merely exemplary in nature and is not intended to limit the present teachings, their application or uses. It should be understood that throughout the drawings corresponding reference numerals can indicate like or corresponding parts and features.  
         [0017]     With reference to  FIGS. 1 and 2 , the present teachings generally include a fastening tool  10  having a main housing  12  that can contain a driving mechanism  14  for driving one or more fasteners  16 , such as a nail or a staple. The fastening tool  10  can include a handle  18 , a nosepiece  20  that can be disposed below the main housing  12  and a magazine  22  that can be connected to the nosepiece  20  and the handle  18 . A trigger assembly  24  can be disposed on the main housing  12  and/or the handle  18  for activating the driving mechanism  14 , as is known in the art. The driving mechanism  14  can include, for example, pneumatic-based systems such as those shown in commonly assigned U.S. Pat. Nos. 3,673,922 or 5,181,450, or an electrical system such as those shown in U.S. Pat. No. 4,928,868. The above references are hereby incorporated by reference in their entirety as if fully set forth herein.  
         [0018]     With reference to  FIGS. 5 and 6 , the magazine  22  can contain the fasteners  16  and can sequentially feed the fasteners  16  into a driver blade channel  26 . Once the fasteners  16  are aligned in the driver blade channel  26 , a driver blade  28  can be extended from a retracted condition ( FIG. 1 ) to drive one of the fasteners  16  out of the driver blade channel  26  and into a workpiece  30  ( FIG. 1 ). The driver blade  28  can extend from the retracted condition to an extended condition, when the driving mechanism  14  is activated via the trigger assembly  24 , as is known in the art.  
         [0019]     With reference to  FIGS. 4, 7  and  8 , the magazine  22  can include a pusher bearing  32  that urges a pusher surface  34  on a pusher block  36  against the fasteners  16  to urge the fasteners  16  toward the nosepiece  20 . Because the pusher block  36  can move relative to the pusher bearing  32 , it can be shown that the pusher block  36  can provide relatively more uniform pressure against the fasteners  16  as the pusher block  36  urges the fasteners  16  toward the nosepiece  20 . Because the pusher block  36  can move or rock about the pusher bearing  32 , the pusher surface  34  of the pusher block  36  can be disposed at a non-parallel orientation relative the pusher bearing  32  and a pusher rod or bar  38  on which the pusher bearing  32  slides. Because the pusher surface  34  can abut the fasteners  16  in an orientation that is not parallel to a force exerted against the pusher block  36 , it can be shown that the propensity for the fasteners  16  to jam in the magazine  22  can be reduced relative to a pusher block (not shown) that is slidable within the magazine but which is otherwise not moveable or able to rock about a pusher rod or other suitable portions of the magazine  22 .  
         [0020]     With reference to  FIGS. 3, 4  and  6 , the contact trip mechanism  42  can include a lower member  40 . The lower member  40  can have a first portion  44  that is associated with the nosepiece  20  and can be coupled to a tip  46  that can contact the workpiece  30  ( FIG. 1 ). A second portion  48  of the lower member  40  can be coupled to a depth adjustment mechanism  50  disposed beneath the trigger assembly  24 . When the tip  46  is pressed against the workpiece  30 , as shown in  FIG. 1 , the contact trip mechanism  42  can move from an extended condition to a retracted condition. When the contact trip mechanism  42  is positioned in the retracted condition, the contract trip mechanism  42  can permit the driving mechanism  14  of the fastening tool  10  to be activated via the trigger assembly  24 , as is known in the art. When the contact trip mechanism  42  is positioned in the extended condition, the fastening tool  10  cannot be activated.  
         [0021]     The trigger assembly  24  can have a main trigger  52  that can be pivotally attached to the main housing  12  or the handle  18  and a supplemental trigger  54  that can be pivotally attached to the main trigger  52 . When the main trigger  52  and the contact trip mechanism  42  are activated (i.e., the lower member  40 , the tip  46 , etc. move to the retracted condition), the supplemental trigger  54  can move a valve or a switch to activate the driving mechanism  14 . It will be appreciated that the supplemental trigger  54  can move a switch when the driving mechanism  14  is an electric system or an airflow control valve when the driving mechanism  14  is a pneumatic system. Operation of the trigger assembly in combination with the contact trip assembly is well known in the art and is described in, for example, commonly assigned U.S. Pat. No. 5,785,228, which is incorporated by reference in its entirety as if fully set forth herein.  
         [0022]     With reference to  FIGS. 3 and 5 , the magazine  22  includes an outer case  56  in which an inner rail  58  can slide from an open position ( FIG. 3 ) to a closed position ( FIG. 1 ). In the open position, one or more of the fasteners  16  can be added to the magazine  22 , albeit in a position where the inner rail  58  is moved farther away from the nosepiece  20  than what is illustrated in  FIG. 3 . The inner rail  58  can then be closed, i.e., moved to the closed position, as shown in  FIG. 1 , to urge the fasteners  16  against the nosepiece  20  and thus align one of the fasteners  16  in the driver blade channel  26 , as shown in  FIG. 6 .  
         [0023]     The pusher block  36  can be in an upside down U-shaped configuration and ride over a top member  60  of the inner rail  58 . In this regard, the pusher surface  34  can be defined by a pair of walls  62  connected by a top portion  64  of the pusher block  36 . The pusher surface  34  can be disposed to generally match the orientation of the fasteners  16 , e.g., a surface of one staple  66  (i.e., the last staple) abuts the pusher surface  34  where the staple  66  and the pusher surface  34  are ideally parallel, as shown in  FIGS. 7 and 8 .  
         [0024]     The pusher block  36  can be made of acetal, which can be also be known as polyacetal, polyoxymethylene or polyformaldehyde. Other suitably performing polymers can also be used to form the pusher block  36 . For example, the pusher block can be made of Delrin® readily available from DuPont or Celcon® readily available from Ticona (Florence, Ky.).  
         [0025]     When the pusher block  36  is made of acetal or other suitable material, the pusher block  36  has a coefficient of friction that can be less than or equal to the coefficient of friction of the inner rail  58  and/or the outer case  56  on and/or in which the pusher block  36  slides. The inner rail  58  and the outer case  56  can be made of aluminum or other suitable metals or plastics. The ability of the pusher block  36  to more easily slide along the inner rail  58  can reduce the propensity of the fasteners  16  jamming in the magazine  22 .  
         [0026]     The inner rail  58  can include a front end  68  and a rear end  70 . The pusher rod or bar  38  can be disposed between the front end  68  and the rear end  70 . An inner nose member  72  associated with the nosepiece  20  can connect to the front end  68 , while a magazine bumper  74  can connect to the rear end  70 .  
         [0027]     When the inner rail  58  is moved to the closed position ( FIG. 1 ), the inner nose member  72  approaches an outer nose member  76 , also of the nosepiece  20 , but can remain spaced from the outer nose member  76 . The spacing between the outer nose member  76  and the inner nose member  72  can be sufficient to define the driver blade channel  26 , (i.e. the channel through which one of fasteners  16  travels as it is driven into the workpiece  30 ). Moreover, the fasteners  16  can be urged against a surface of the outer nose member  76  that can face the driver blade channel  26  and thus align one of the fasteners  16  in the driver blade channel  26 , as shown in  FIG. 5 .  
         [0028]     A nose cover  78  can connect to the outer nose member  76  to form a front face  80  of the nosepiece  20 . The nose cover  78  can, moreover, hold heads  82  of fasteners that can couple the nosepiece  20  to the magazine  22 .  
         [0029]     The pusher bearing  32  can be formed with a through hole  84  that slidably receives the pusher rod  38 . In addition, a spring  86  can be disposed over the pusher rod  38  such that the pusher rod  38  is threaded through the spring  86 . The spring  86  can be coupled to the pusher bearing  32  to bias the pusher bearing  32  towards the nosepiece  20 . The pusher bearing  32  can, in turn, be coupled to the pusher block  36 .  
         [0030]     The pusher block  36  can define a pair of rounded apertures  88  formed in each of the walls  62  that can be configured to receive the pusher bearing  32 . The pusher bearing  32  can also have a rounded or semi-cylindrical configuration ( FIG. 4 ) that can be received in the apertures  88  of the walls  62  of the pusher block  36 . In this regard, a ball and socket joint  90  can be formed between the pusher bearing  32  and the pusher block  36 . The rounded configuration of the pusher block apertures  88  and the pusher bearing  32  can permit the pusher block  36  to move (i.e., pivot) relative to the pusher bearing  32  as the pusher bearing  32  urges the pusher block  36 , and the fasteners  16 , toward the nosepiece  20 .  
         [0031]     The pusher bearing  32  can have walls  92  that can be generally parallel to one another. The pusher bearing  32  can also have a generally cylindrical surface  94  that can be bounded by the walls  92 . An imaginary line  96  can extend in a direction generally normal to the cylindrical surface  94 . The imaginary line  96  can also be generally perpendicular to an imaginary line  98  that can extend from one the walls  92 . The walls  62  of the pusher block can be generally flush with the walls  92  of the pusher bearing  32 . As such, the pusher block apertures  88  can have an arcuate surface  100  that can receive the cylindrical surface  94  of the pusher bearing  32 . The pusher block  36 , therefore, can be operable to move or rock relative to or about the pusher bearing  32 , as the pusher bearing  32  urges the pusher block  36 , and the fasteners  16 , toward the nosepiece  20 .  
         [0032]     For example and with reference to  FIGS. 7 and 8 , a force applied by the spring  86  in a first direction  102  can be, in turn, applied by the pusher surface  34  to the staple  66  in a second direction  104 . The first direction  102  and the second direction  104 , in some instances, are not parallel and the second direction  104  need not be parallel to the pusher rod  38 . Since the pusher block  36  is able to move about the pusher bearing  32 , the pressure applied to the fasteners  16  by the pusher block  36  can be more uniform as compared to a pusher block that is rigidly attached to a pusher bearing or other suitable portion of a magazine.  
         [0033]     With reference to  FIG. 3 , the magazine  22  can be coupled to the main housing  12  and/or the handle  18  at a first connection point  106  and a second connection point  108 . The first connection point  106  can be adjacent to the nosepiece  20  such that a front end  110  of the magazine  22  can be coupled to the nosepiece  20  to form the driver blade channel  26  therebetween. At the second connection point  108 , the magazine  22  connects to a rear end  112  of the handle  18 .  
         [0034]     At the second connection point  108 , the housing  12  can include a magazine clip  114 . The magazine clip  114  ( FIG. 4 ) can pivot on a pin  116  that is coupled to the handle  18 . Moreover, a spring  118  can bias the magazine clip  114  in a locked position, as shown in  FIG. 1 . By pressing the magazine clip  114  toward the housing  12  and against the bias of the spring  118 , the magazine clip  114  can be moved from the locked position to an unlocked position. With the magazine clip  114  in the unlocked position, the inner rail  58  can be extracted from the outer case  56  of the magazine  22  and pulled away from the nosepiece  20 , as shown in  FIG. 3 . By pulling the inner rail  58  out and away from the nosepiece  20 , the fasteners  16  can be added to the magazine  22  to replenish the fasteners  16  in the magazine  22 .  
         [0035]     When fasteners  16  are added to the magazine  22 , the inner rail  58  can be returned to the closed position, as shown in  FIG. 1 . The magazine bumper  74  that can be connected to the inner rail  58 , can engage the magazine clip  114  to hold the magazine  22  in the closed position, as also shown in  FIG. 1 .  
         [0036]     With reference to  FIGS. 6, 7  and  8 , when one or more fasteners  16  are contained within the magazine  22 , the pusher block  36  will necessarily butt up against the last fastener (e.g. the staple  66 ) contained in the magazine  22  opposite the nosepiece  20 . The spring  86  over the pusher rod  38  will be compressed between the pusher bearing  32  and the magazine bumper  74  ( FIG. 3 ) and thereby bias pusher bearing  32  in a first direction toward nosepiece  20 . The force exerted on the pusher block  36  is transferred to the fasteners  16  thus urging the fasteners  16  toward the nosepiece  20  to dispense the fasteners  16  into the driver blade channel  26 . Because the pusher block  36  can move about the pusher bearing  32 , the pusher surface  34  can apply pressure to the fasteners  16  in a second direction  104  that is not parallel to the first direction  102 . Moreover, the pusher block  36  can rock about the pusher bearing  32  such that the second direction  104  can form an acute angle with the first direction upwardly and/or downwardly relative to the examples illustrated in  FIGS. 7 and 8 .  
         [0037]     While specific aspects have been described in this specification and illustrated in the drawings, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the present teachings, as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various aspects of the present teachings may be expressly contemplated herein so that one skilled in the art will appreciate from the present teachings that features, elements and/or functions of one aspect of the present teachings may be incorporated into another aspect, as appropriate, unless described otherwise above. Moreover, many modifications may be made to adapt a particular situation, configuration or material to the present teachings without departing from the essential scope thereof. Therefore, it may intended that the present teachings not be limited to the particular aspects illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the present teachings but that the scope of the present teachings will include many aspects and examples following within the foregoing description and the appended claims.