Abstract:
In one embodiment, a power hand tool includes a housing containing a working shaft, and a vibration isolation assembly, the vibration isolation assembly including at least one base member including a base portion fixed with respect to the housing, at least one vibration isolation portion including a first portion operably connected to the at least one base member, the at least one vibration isolation portion configured to isolate vibration in at least one direction, and a grip member having an outer surface configured to be gripped by a user and an inner surface operably connected to an outer portion of the at least one vibration isolation portion.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/784,186 filed Mar. 14, 2013, and U.S. Provisional Application No. 61/806,289 filed Mar. 28, 2013, the entirety of which are both incorporated herein by reference. 
     
    
     FIELD 
       [0002]    This disclosure relates to power hand tools and more specifically to power hand tools which create vibration. 
       BACKGROUND 
       [0003]    Reciprocating tools that are motor driven, such as saber saws, larger reciprocating saws and the like are usually driven by electric motors that have a rotating output shaft. The rotating motion is translated into reciprocating motion of a working shaft for moving a saw blade or the like in a reciprocating manner. Various approaches have been developed which translate the rotational motion into reciprocating motion. A common approach is the incorporation of a wobble plate drive. 
         [0004]    A “wobble plate” assembly is a configuration wherein a shaft has an angled portion on which an arm is mounted through a ball bearing assembly. The arm is slidingly positioned within a portion of a plunger assembly. As the angled portion of the shaft rotates, the arm translates the rotation of the shaft into a reciprocating movement of the plunger assembly. One example of a reciprocating tool which incorporates a wobble plate drive is U.S. Pat. No. 7,707,729, which issued on May 4, 2010, the entire contents of which are herein incorporated by reference. 
         [0005]    As the working shaft of the plunger assembly moves along an axis, a significant amount of momentum is created. All of this momentum is absorbed by the tool as the plunger assembly reverses direction. Thus, a user of a reciprocating tool incorporating a wobble plate drive must contend with a powerfully vibrating device. In order to make such reciprocating tools more controllable, reciprocating tools such as the device in the &#39;729 patent incorporate a counterweight which is driven by a secondary wobble plate in a direction opposite to the direction of the plunger assembly. While the incorporation of a secondary wobble plate and counterweight is effective, a user is still exposed to a significant amount of undesired vibration. 
         [0006]    Other devices for changing rotational movement to reciprocating movement include scotch yoke mechanism and crank sliders. Such devices are disclosed in U.S. Pat. No. 6,357,125 which issued on Mar. 19, 2002, and U.S. Patent Publication No. 2008/0134855, which was published on Jun. 12, 2008, the entire contents of which are both herein incorporated by reference. These systems also suffer from undesired vibration. 
         [0007]    In the field of rotary hammers, some effort has been made to reduce the vibrations experienced by a user by decoupling the handle from the tool. The isolators only isolate the handle from impacts in one direction. Since reciprocating saws have a large reciprocating mass that is accelerated and decelerated in both the forward and reverse direction, large vibration forces are generated in both the forward and reverse direction. 
         [0008]    Some reciprocating saws have been developed which attempt to isolate the handle by trapping an isolating elastomer between the handle and the tool housing. A certain level of isolation has been achieved, but additional isolation is desired. 
         [0009]    Other hand power tools also create vibrations which can be injurious to a user, particularly when the power tool is used over prolonged periods. Such tools include grinders, sanders, routers, and other rotary, oscillating, and reciprocating tools. 
         [0010]    A need exists for a power hand tool which reduces vibration experienced by a user. A further need exists for a power hand tool which reduces vibration which does not rely upon bulky assemblies. A system which reduces vibrations in a power hand tool while reducing costs associated with vibration reduction would be further beneficial. 
       SUMMARY 
       [0011]    In one embodiment, a power hand tool includes a housing containing a working shaft, and a vibration isolation assembly, the vibration isolation assembly including at least one base member including a base portion fixed with respect to the housing, at least one vibration isolation portion including a first portion operably connected to the at least one base member, the at least one vibration isolation portion configured to isolate vibration in at least one direction, and a grip member having an outer surface configured to be gripped by a user and an inner surface operably connected to an outer portion of the at least one vibration isolation portion. 
         [0012]    In another embodiment, a reciprocating tool provides improved vibration isolation by allowing for a greater amount of displacement of the vibrating tool with respect to the decoupled tool. Both the forward grip and the rear handle of a saw in one embodiment are provided with isolating mechanisms which isolate the grip/handle from forces occurring in both forward and rearward directions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  depicts a side perspective view of a reciprocating tool incorporating a vibration isolation system in accordance with principles of the disclosure; 
           [0014]      FIG. 2  depicts a side cross-sectional view of the isolation system of  FIG. 1 ; 
           [0015]      FIG. 3  depicts a side cross-sectional view of the isolation system of  FIG. 1 ; 
           [0016]      FIG. 4  depicts a bottom cross-sectional view of the isolation system of  FIG. 1 ; 
           [0017]      FIG. 5  depicts a side cross-sectional view of a vibration isolation system that can be used with the tool of  FIG. 1 ; 
           [0018]      FIG. 6  depicts a side cross-sectional view of a vibration isolation system that can be used with the tool of  FIG. 1 ; 
           [0019]      FIGS. 7-11  depict views of a vibration isolation system that can be used with the tool of  FIG. 1  which incorporates elastomer pads; 
           [0020]      FIGS. 12-15  depict views of a vibration isolation system that can be used with the tool of  FIG. 1  which incorporates elastomer cylinders; 
           [0021]      FIGS. 16-19  depict isolation systems incorporating isolators of different shapes and orientations to provide modified stiffness characteristics; 
           [0022]      FIGS. 20-21  depicts an isolation system which includes differently shaped isolators to provide a varying stiffness depending upon the usage of the tool; 
           [0023]      FIGS. 22-24  depict embodiments wherein an isolator is shaped in order to provide different stiffness characteristics by forming voids within the isolator; 
           [0024]      FIGS. 25-28  depict an embodiment which includes press fit components for ease of construction; 
           [0025]      FIGS. 29-30  depict an embodiment of an isolation system which traps isolator pads between two housing portions for ease of manufacturing; 
           [0026]      FIGS. 31-32  depict an embodiment of an isolation system wherein an elastomeric pad is bonded to pieces of metal to form an assembly which is easily mounted to a tool housing; 
           [0027]      FIGS. 33-34  depict an embodiment of an isolation system wherein an elastomeric pad is bonded to a sled housing on one side and a piece of metal on the other side to form an assembly which is easily mounted to a tool housing 
           [0028]      FIGS. 35-36  depict an embodiment of an isolation system wherein an elastomeric pad is formed with locking tabs which are easily mounted to a sled housing 
           [0029]      FIGS. 37-38  depict an embodiment of an isolation system wherein a port is formed in the sled and isolation pad to provide for dust removal capability; 
           [0030]      FIG. 39  depicts an isolation system which includes a quick release button; 
           [0031]      FIGS. 40-42  depict an isolation system that includes a button which allows the isolation system to be quickly activated/deactivated; 
           [0032]      FIGS. 43-45  depict an embodiment of an isolation system wherein a used can easily adjust the stiffness of the system; 
           [0033]      FIG. 46  depicts an embodiment of an isolation system wherein an elastomeric pad in the form of bars is formed on a tool housing and a rubber boot encloses the elastomer pad; 
           [0034]      FIG. 47  depicts an embodiment of an isolation system wherein an elastomeric pad in the form of cylinders is formed on a tool housing and a rubber boot encloses the elastomer pad housing; 
           [0035]      FIG. 48  depicts an embodiment of an isolation system which is formed as a one piece insert molded system; 
           [0036]      FIG. 49  depicts an embodiment of an isolation system which includes thermal protection; 
           [0037]      FIG. 50  depicts an embodiment of an isolation system wherein a rubber boot encloses the isolation system; and 
           [0038]      FIGS. 51-54  show the isolation systems disclosed herein in use with various types of hand power tools. 
       
    
    
     DESCRIPTION 
       [0039]    For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the disclosure is thereby intended. It is further understood that the present disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one skilled in the art to which this disclosure pertains. 
         [0040]      FIG. 1  depicts a reciprocating saw  100  including an outer housing  102  which includes a handle portion  104 , a motor portion  106 , and a nose portion  108 . The handle portion  104  includes a handle  112 , a dual-speed switch  114 , and a variable speed trigger  116 . The handle portion  104  is configured to removably receive a battery pack  118  which in some embodiments is replaced by a corded power supply. 
         [0041]    The nose portion  108  includes a grip  124  which includes an outer surface shaped to allow a user to grip the tool  100  while the tool  100  is in use. A foot plate assembly  120  is located forwardly of the nose portion  108 . 
         [0042]    The motor portion  106  includes a number of ventilation ports  122  which are used to provide cooling air to a motor (not shown). The motor (not shown) rotatably drives a wobble plate assembly (not shown) which in turn drives a working shaft connected to a chuck assembly (not shown) which removably supports a saw blade  126 . The saw blade  126  is driven along a plunger axis  128  by the working shaft which reciprocates along the plunger axis  128 . 
         [0043]    The grip  124  includes a sled  140 . The sled  140  is supported by the housing  102  by two base members in the form of pins  142 / 144  which are rigidly connected to the housing  102 . The pins  142 / 144  extend through a respective rear washer supporting isolator  146 / 148  each of which is fixedly connected to a respective rear isolator  150 / 152 . 
         [0044]    The isolators  150 / 152  are positioned within a rear isolator cavity  154 . 
         [0045]    The pins  142 / 144  further extend through a respective one of a pair of support bushings  156 / 158  which are pressed into the sled  140 . The support bushings  156 / 158  are positioned between the rear isolators  150 / 152  and a pair of front isolators  160 / 162 . The front isolators  160 / 162  are located within a front cavity  168  of the sled  140 . A pair of front washer supporting isolators  164 / 166  are fixedly attached to a respective one of the pins  142 / 144  at a location forward of the front isolators  160 / 162 . These bushings  156 / 158  provide rigidity in to tool motion in both directions that are transverse to the front to back axis. This acts to prevent rocking of the tool body as well as increases control of the tool body during cutting. A front connector  170  extends between the pins  142 / 144  at a location between the front washer supporting isolators  164 / 166  and the front isolators  160 / 162 . The front ends of the pins  142 / 144  are not attached to any other part of the reciprocating saw  100 . 
         [0046]    In operation, the reciprocating tool  100  generates vibrations along the plunger axis  128  as the working shaft reciprocates. The vibrations are isolated, however, by the grip  124 . Specifically, as the tool  100  moves in the direction of the arrow  180  of  FIGS. 1 and 4 , the sled  124  does not initially move since the sled  124  is not fixedly connected to the housing  102  in which the working shaft reciprocates. The housing  102  thus pushes against the rear washer supporting isolators  146 / 148 . Movement of the rear washer supporting isolators  146 / 148  generates a force against the rear isolators  150 / 152 . The rear isolators  150 / 152  are made of an elastomer, a spring, or the like. Elastomers provide a given spring rate but also have a damping value which allows for a certain level of energy dissipation and is well suited for eliminating/reducing the chances of vibration amplification at the speeds at which the reciprocating saw  100  operates. Various springs also have a range of damping characteristics which can eliminate/reduce the chances of vibration amplification. 
         [0047]    Consequently, the rear isolators  150 / 152  absorb a desired amount of the energy of the vibration, and also reduce the movement of the grip  124  in the direction of the arrow  180 . Depending upon the particular embodiment, the housing  102  may begin to move in a direction opposite to the arrow  180  prior to movement of the sled in the direction of the arrow  180 . 
         [0048]    Once the reciprocating tool  100  reaches the end of a stroke and begins to move in the direction opposite to the arrow  180 , the pins  142 / 144  move rearwardly with respect to the sled  140 . The rearward movement of the pins  142 / 144  forces the front washer supporting isolators  164 / 166  against the front connector  170  which in turn presses against the front isolators  160 / 162 . The front isolators  160 / 162  are also made of an elastomer, a spring, or the like. Accordingly, as the front connector  170  presses against the front isolators  160 / 162 , the front isolators  160 / 162  compress, thereby absorbing the desired amount of energy of the vibration, and also reducing the movement of the grip  124  in the direction opposite to the arrow  180 . The front connector  170  spreads the force more evenly across the front isolators  160 / 162  even in situations where the load is generated more heavily on one side of the grip. 
         [0049]    The net effect of this isolated system is that it allows the tool to vibrate back and forth but the pin—bushing—isolator system decouples the user&#39;s hands from the vibration in axis of the pins. While the isolation system in the embodiment of  FIG. 1  was described with respect to the grip, in some embodiments the isolation system is alternatively or additionally incorporated into the handle  112 . 
         [0050]    One or both of the grip/handle isolation systems in different embodiments may be modified for a particular application. By way of example,  FIG. 5  depicts another isolator that in different embodiments is incorporated into one or both of the grip and handle of  FIG. 1 . The isolation system  200  of  FIG. 5  includes a sled  202  which is spaced apart from a housing  204 . A pin  206  is fixedly attached to the housing  204  and to a front and rear snap rings  208  and  210 , respectively. The snap rings  208  and  210  are separated from an isolator  212  by a pair of washers  214 / 216 . The pin  206  slidingly engages a support bushing  218  which is press-fit within the sled  202 . These bushings  218  provide rigidity in to tool motion in both directions that are transverse to the front to back axis. This acts to prevent rocking of the tool body as well as increases control of the tool body during cutting. 
         [0051]    The snap rings  208  and  210  on the pin  206  push/pull the washers  214 / 216 , which in turn acts to compress the isolator  212  in response to the vibrating movement of the pin  206 . In this embodiment, one less isolator is needed on each pin as compared to the embodiment of  FIG. 1 . While only a single pin  206  is depicted in  FIG. 5 , more pins may be present in the system. 
         [0052]    Additionally, while  FIGS. 1 and 5  depict grips which extend about the plunge axis, the isolators can also be used to isolate two ends of, for example, the handle  112 . Thus, isolators are readily employed in both grips and handles. 
         [0053]    In some embodiments, the “stiffness” of the isolating system can be modified.  FIG. 6  depicts an isolation system  250  which includes a set screw  252  in a threaded end portion  254  of a pin  256 . The set screw  252  can be used to modify the compression on the isolators  258 / 260  to provide a desired amount of vibration isolation of the sled  262 . 
         [0054]      FIGS. 7-11  depict a vibrations isolation system  300  which includes an outer elastomer sled  302  and, in this embodiment, a pair of inner elastomer pads  304 . In other embodiments, springs are used in place of the elastomer pads  304 . The elastomer sled and pads/springs provide three axes of vibration isolation. In the front-to-back direction the system provides shear loading of the pads/springs. In the side-to-side direction, the system provides compressive/tensile loading of the pads/springs. Finally, in the up-down direction, the system provides shear loading of the pads/springs. 
         [0055]    While the outer elastomer sled  302  is depicted as generally rectangular, in other embodiments the sled has a more contoured shape, such as the shape of the sled in the grip  124 . The pads  304  are also contoured to fit within the sled. In embodiments incorporating springs, the spring dimensions are selected to fit within the sled. The dimensions, durometer, and damping properties of the elastomer pads/springs and sled are selected in order to minimize vibration being passed on from the tool to the user&#39;s hands. 
         [0056]      FIGS. 12-15  depict a vibrations isolation system  400  which includes an outer elastomer sled  402 . The sled  402  rides upon four isolators  404 ,  406 ,  408 , and  410  which may be elastomer cylindrical tubes or springs. The isolators  404 / 408  are supported by a pin  412  while the isolators  406 / 410  are supported by a pin  414 . The pin  412  is rigidly connected to the housing within a receptacle  418  and the pin  414  is rigidly connected to the housing within a receptacle  420 . 
         [0057]    The elastomer sled  402  and isolators provide three axes of vibration isolation. In the front-to-back direction the system provides shear loading of the isolators. In the side-to-side direction, the system provides compressive/tensile loading of the isolators. Finally, in the up-down direction, the system provides shear loading of the isolators. The dimensions, durometer, and damping properties of the elastomer tubes/springs and sled are selected in order to minimize vibration being passed on from the tool to the user&#39;s hands. 
         [0058]    The amount of vibration isolation in a particular implementation is optimized in various manners. Vibration isolation is optimized by way of a combination of material properties and geometries. For example, the stiffness provided by the elastomer pad  304  in  FIG. 8  can be modified by selecting, for a given size and shape of the pad  304 , a material which provides the desired stiffness. For a given material, stiffness can be modified by increasing or decreasing the dimensions of the material (length, width, and thickness). 
         [0059]      FIG. 16  depicts a power hand tool  450  which is similar to the power hand tool on which the pad  304  is mounted. The pad  452  which is used in the power hand tool  450  is made from the same material as the pad  304 . The stiffness of the pad  452  is modified, however, since the pad  452  is embodied as a group of bars  454 . The bars  454  are oriented such that the stiffness of the pad  452  along the axis  456  is much less than the stiffness of the pad  304 , while the stiffness of the pad  452  along the axis  458  is only slightly less than the stiffness of the pad  304 . 
         [0060]    By modifying the size and numbers of the elastomeric bars  452 , the stiffness characteristics can be further modified. By way of example, the pad  460  in  FIG. 17  includes stiffening components in the form of bars  462  which are thinner than the bars  452 , thus modifying the stiffness of the pad  460 . The pad  464  in  FIG. 18  includes stiffening components in the form of elastomeric bars  466  which have been oriented to provide enhanced stiffness along the axis  468 . Thus, the orientation of the pad can be modified to provide the desired stiffness characteristics. 
         [0061]    In some embodiments, it may be desired to have reduced stiffness along two axes of the power hand tool.  FIG. 19  depicts an elastomeric pad  470  which is constructed with a group stiffening components in the form of cylinders  472 . The cylinders reduce the stiffness along all axes of the tool, allowing an overly stiff elastomer to be used without maintaining a high stiffness in the pad  470 . 
         [0062]    Additional stiffness optimization is realized in some embodiments by providing multiple geometries of stiffening components within a single pad. By way of example,  FIGS. 20-21  depict an elastomeric pad  474  positioned between a sled  476  and a housing  478  of a power hand tool. The pad  474  includes connecting bars  480  and truncated bars  482 . Each of the truncated bars  482  is located between a connecting bar  480  and a stiffening rib  484  of the housing  478 . 
         [0063]    The embodiment of  FIGS. 20-21  provide varying isolator pad  474  geometry for a shear loaded system that allows for progressively stiffening the elastomer pad  474  upon larger deflections. Small deflections of the system result in a stiffness defined only by one set of pads, the connector pads  480 , which provides a very loose (non-stiff) system. Larger deflections lead to the connector pads  480  bottoming out on the truncated bars  482  thereby increasing the stiffness of the system. After reaching a certain deflection, the pads  480  and  482  bottom out on the rigid metal ribs  484  and the system becomes significantly more stiff. This progressive increase in stiffness limits the user&#39;s looseness of the handle when high loads are applied while still allowing for ideal isolation properties under low loads. 
         [0064]    The embodiment of  FIGS. 20-21  functions in a similar manner in compression. In cases of small displacements, the connector pads  480  are the only isolator set compressing. Larger displacements leads to the sled  476 , which in one embodiment is a metal plate, coming into contact with the truncated bars  482  and thus stiffening the system. Under even larger displacements, the sled  476  comes in contact with the rigid metal ribs  484  and rigidly bottoms out preventing additional displacement. This embodiment thus shows a progressively stiffening isolation system on a power hand tool. 
         [0065]    The use of different geometries or shape factors can also be used with isolation systems similar to the isolation system of  FIGS. 12-15 . By way of example,  FIG. 22  depicts a vibrations isolation system  490  which includes an outer elastomer sled  492 . The sled  402  rides upon two elastomer cylindrical tubes  494  and  496 . The elastomer cylindrical tube  494  is slidingly supported by a pin  498  while the elastomer cylindrical tube  496  is slidingly supported by a pin  500 . The pin  494  is rigidly connected to the housing within a receptacle  502  and the pin  496  is rigidly connected to the housing within a receptacle  504 . 
         [0066]    The isolation system  510  of  FIG. 23  is substantially the same as the isolation system  490  of  FIG. 22 . The difference is that the elastomer cylindrical tubes  512 / 514  include a plurality of bores  516 . The bores  516  modify the stiffness longitudinally and radially. The positioning of the bores  516  and the surrounding structure determine the extent of the modification radially and longitudinally. For example, the tubes  512 / 514  are configured in one embodiment to spread an applied load evenly across the ends of the cylinders. Thus, the location of the bores  516  is less important as compared to the number of bores. Radially, however, the manner in which force is transferred about the bores  516  is dependent upon the positioning of the bores  516 . 
         [0067]      FIG. 24  depicts an isolation system  520  which is similar to the system  510  of  FIG. 23 . The main difference is that additional stiffness modification is accomplished by providing an increased number of bores  522  through the elastomer cylindrical tubes  524 / 526 . 
         [0068]    While various embodiments of isolation systems have been depicted above, the principles set forth in each of the specific embodiments are incorporated in different combinations in other embodiments. Additional modifications are also possible so as to provide additional benefits for particular embodiments. Thus, additional components may be added to ease manufacturing.  FIGS. 25-28 , for example, depict an isolation system  530  which includes a sled supported by two pins  532 / 534  which are attached to a housing  536 . Two elastomer cylinders  538 / 540  are bonded to the pins  532 / 534  and each cylinder  538 / 540  has a tube  542 / 544  bonded to its outer diameter. 
         [0069]    During manufacturing, the elastomer cylinders  538 / 540  are bonded to the pins  532 / 534  on the inner diameter of the elastomer cylinders. The isolator then has a tube  542 / 544  bonded to its outer diameter. This method of manufacturing facilitates production assembly of the sled system. A press fit of the pins  532 / 534  to the housing and a press fit of the metal tube to corresponding bores in the anti-vibration handle allow the system to be secured in a decoupled fashion through the isolators. 
         [0070]    The above described embodiments can be manufactured in a variety of processes. In different embodiments, the location and quantity of tubeform isolators is varied, and the location and quantity of isolator pads is varied as well. For example, while several embodiments showing tubes in an “over/under” configuration have been shown, other combinations and positioning of the tubes are incorporated in other embodiments. 
         [0071]    Similarly, some of the above described embodiments depict two isolator pads, one located on the left and one located on the right side of the output shaft. In other embodiments, other combinations and positioning of the pads are incorporated. One such embodiment has pads located above and below the shaft, and another embodiment has three or four pads located equidistant about the shaft. 
         [0072]    To facilitate manufacture of some embodiments, a clamshell sled is used.  FIGS. 29-30  depict an isolation system including two housings  550 / 552  which, when fastened together, effectively trap isolator pads  554 / 556  between the sled housings  550 / 552  and the housing  558  of the power tool. 
         [0073]    In some embodiments, an elastomer pad  560  (see  FIG. 31 ) is bonded to pieces of metal  562 / 564 . This subassembly is easily assembled in an anti-vibration handle  566  such as by mating with corresponding pockets/recesses  568 / 570  in the handle and housing to rigidly link the metal pads to the housing and handle while still allowing for the decoupling of the handle from the tool itself as shown in  FIG. 32 . 
         [0074]    In another embodiment (see  FIG. 33 ), an elastomer pad  572  is directly molded onto the sled/handle housing  574  on one side of the elastomer and bonded to a metal pad  576  on the other side of the elastomer pad  572  to assist in assembling the handle to the power tool housing as depicted in  FIG. 34 . 
         [0075]      FIGS. 35-36  depict an embodiment which does not require bonding. The elastomer pads  580  are formed with securing tabs  582 . When the elastomer pads  580  are inserted in the housing  584 , the protruding tabs  582  lock in the undercut portion of the housing &amp; handle  584 . While one geometry of locking tabs is depicted, other geometries are used in other embodiments. 
         [0076]    The above described embodiments are modified to provide for additional functionality in some embodiments.  FIGS. 37 and 38  depict an isolation system  590  that is modified to provide a port through which a dust removal hose  592  draws a suction. The isolation system  590  in some embodiments is modified in shape and location to optimize collection of dust, such as by enclosing the blade holder and a portion of the blade in a portion of the tool housing or housing of the isolation system  590 . 
         [0077]    While some of the clamshell embodiments depicted above include a screw or threaded fastener to attach the clamshells together, some embodiments provide for a quick release mechanism.  FIG. 39  depicts an isolation system  596  which includes a quick-release button  598  which provides the user with a method for quickly removing the front handle/isolation system  596 . This embodiment is desirable for situations where the user is working in tight areas that the front handle may be preventing the user from being able to access. 
         [0078]      FIGS. 40-41  depict an isolation system  600  which includes an activation button  602  which provides the user with a method for quickly activating/deactivating the handle/isolation system  600 . This embodiment is desirable for situations where the user does not desire to have the decoupled front handle/system (vibration isolated handle)  600 . The activation button  602  can be engaged/disengaged to switch between coupled handle (no anti-vibration as in  FIG. 42 ) and decoupled handle (isolators are loaded and anti-vibration system is engaged as in  FIG. 41 ). 
         [0079]    In the above described embodiments, a further modification is to make the stiffness of the system user changeable. By way of example,  FIGS. 43-45  depict an isolation system  610  that includes levers  612 . By moving the levers between the full isolation position of  FIG. 44  and the reduced isolation configuration of  FIG. 45 , the stiffness of the system  610  is increased by reducing the effectiveness of the elastomer pads  614  by pressing the ends  616  of the levers  612  into the pads  614 . This variable pre-compression will drive the system stiffness and thus the system&#39;s isolation efficiency. 
         [0080]    The above described embodiments may further be modified to present a lower profile of the vibration isolation system. For example, many of the above described embodiments depict the vibration isolation system as a forward handle or grip that is positioned about the tool housing.  FIG. 46  depicts a vibration isolation system  620  which includes rubber or elastomer ribs  622  molded onto a metal housing  624  of the tool. A rubber boot  626  is also molded onto the housing  624  at a posterior portion of the boot  626 . The anterior portion of the boot  626  interacts with the ribs  622  to provide vibration isolation. The rubber boot  626  acts as a ‘skin’ of sorts allowing the user to grip onto it but also allowing the rubber ribs  622  to translate during shear loading of them (front to back vibration) as well as bend during compressive loading (side to side/up down). The rubber boot in some embodiments is configured to allow air to move between the boot and the housing for cooling and/or debris removal. 
         [0081]    In some embodiments, ribs are formed additionally or alternatively on the boot  626 . In some embodiments, the ribs are formed on the exterior of the boot  626  and are directly contacted by the user&#39;s hands. Moreover, while the ribs  626  are shown in the form of bars, the shape and spacing may be modified in accordance with the various embodiments described above. For example,  FIG. 47  depicts a vibration isolation system  630  that incorporates a pattern of cylinders  632  that are molded to the metal housing  634 . The cylinders  632  could additionally or alternatively be molded to the inside or outside of the boot  636 . 
         [0082]    As can be seen in  FIG. 47 , there is an air gap  638  between the metal front housing  634  and the boot  636 . The boot in this embodiment includes a number of vent holes  640 . By molding or otherwise forming vent holes in this area of the exterior boot, the front housing  634  can benefit from convection by means of cool air being allowed to pass over and in contact with the front housing  634 . This differs from existing front ends where the boot covers the majority of the front housing surface in order to ensure the user is isolated from the heat generated in the mechanism. With the larger gap  638 , vents  640  can be incorporated without the threat of the user injuring themselves due to incidental contact with the hot metal front housing. 
         [0083]      FIG. 48  depicts an isolator system  650  which uses a one piece multiple insert molding operation that combines a rigid Nylon grip surface  652 , isolation material,  654 , and in some embodiments, includes rubber boot material  656 . The isolation material  654  traps the rigid nylon grip surface  652 . This allows the user to grab onto a firm surface while still achieving three axes of vibration isolation. The isolation material  654  can then also be bonded to a traditional rubber boot material to make a one piece assembly onto the front housing of the tool, if desired. 
         [0084]    Yet another modification that is incorporated into various of the above described embodiments is shown in  FIG. 49 . During operation, heat is generated in hand power tools. This heat can negatively affect the performance values of the elastomer (stiffness, damping, etc.) and therefore negatively affect the isolation efficiency of the system. Because of this, in some embodiments this heat transfer is mitigated. Thus,  FIG. 49  shows elastomer pads  660  with the thermal barriers  662  located on either side of the elastomer pad  660 . In different embodiments, thermal barriers  662  are located on both sides of the isolator, or just on the inside surface to minimize the heat transfer to the elastomer from the tool mechanism. 
         [0085]    In some of the above described embodiments, a secondary front handle isolated a user from the tool vibrations. Thus, the user would be holding onto this secondary handle from the exterior. The above described embodiments in some instances are modified by wrapping a rubber boot around both the metal front housing and isolated handle in order to achieve a more aesthetically pleasing appearance. By way of example,  FIG. 50  depicts an isolation system  670  which is enclosed by a boot  672 . The rubber boot  672  flexes in accordance with the relative movements between the metal front housing  674  and the front handle  670 . 
         [0086]    The above described isolation systems have been depicted primarily in use with reciprocating tools. The systems can be used, however, with any desired hand power tool. Thus,  FIG. 51  shows an isolation system  680  used with a drill,  FIG. 52  shows an isolation system  682  used with an oscillating tool,  FIG. 53  shows an isolation system  684  used with a router, and  FIG. 54  shows an isolation system  686  used with a grinder. Moreover, while typically a single isolation system has been depicted in connection with a particular tool, in some embodiments multiple isolation systems are incorporated, some of which may be different from other incorporated isolation systems. 
         [0087]    While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the disclosure are desired to be protected.