Abstract:
A battery-powered carving knife is shown having a housing and a switch which connects and disconnects a battery to a motor. A drive mechanism including a worm gear together with a cam member causes reciprocation of reciprocating blade mounts to reciprocate back and forth in an out of phase fashion. The motor is positioned forward within the housing in motor receiving section, with the drive shaft of the motor facing rearwardly. The blade mounts are driven by the motor, and reciprocate in a position below the motor. The motor and blade mounts are positioned in front of a handgrip section, thereby improving the ergonomics of the device. Alternatively, the drive shaft can be positioned facing forward.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/294,058 filed May 29, 2001, the complete disclosure of which is hereby expressly incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to a battery-powered knife having reciprocating blades for carving or cutting.  
           [0003]    It is well known in the industry of carving knives to include either electrically or battery-powered carving knives. Typically these carving knives include a housing or casing to house the motor, and include a drive mechanism which includes means for driving a pair of carving knife blades in a reciprocating manner such that the knives are 180° out of phase. This back and forth reciprocation of the blades assists in the carving process. Such carving knives are typically used for home use for carving of meats of various sorts, but such knives can also be used for cleaning and preparation of fish. One of the drawbacks to existing products, whether electrically driven or battery-powered, is that the motor is located in the housing in a position such that the motor and/or the battery forms a counterweight to the knife blades, such that the weight must be counteracted by the user by a further carving force to enable the meat to be cut. This provides for a device which is not very ergonomically pleasing to the user and feels very awkward during such use.  
           [0004]    Take for example U.S. Pat. Nos. 3,337,954; 3,432,702; and 3,679,958. All of these mechanisms show a very heavy weight in the area where the casing would be gripped by the user as well as provide a very bulky handgrip for such use. Yet further the device is not very compact as the motor includes the gear drive facing forward which causes a serial arrangement of the components, that is, the batteries-motor-gear drive-knife, causing a stack up of dimensions resulting in an elongate and bulky end product.  
           [0005]    One design, shown in U.S. Pat. No. 5,230,155 shows a motor having the drive shaft facing rearward, but once again the weight distribution is not optimum, as the motor is placed midway within the housing as an extendable and retractable knife assembly is positioned at the front part of the housing. This not only causes a weight distribution issue, but also provides a very bulky handgrip section making the design difficult for the user.  
           [0006]    The objects of the invention then are to improve upon the shortcomings of the prior art. 
       
    
    
       [0007]    The invention will now be described by way of drawing figures where:  
         [0008]    [0008]FIG. 1 is a perspective view of the carving knife of the present invention;  
         [0009]    [0009]FIG. 2 is a view of the carving knife of FIG. 1 with one-half of the outer housing cover removed, and partially in section;  
         [0010]    [0010]FIG. 3 is an enlarged view of the drive section of the carving knife of FIG. 2 partially in section;  
         [0011]    [0011]FIG. 4 is a cross-sectional view through lines  4 - 4  of FIG. 3;  
         [0012]    [0012]FIG. 5 is a side plan view of the left reciprocating blade mount, that is, the one viewed in FIG. 3;  
         [0013]    [0013]FIG. 6 is an end view of the reciprocating blade mount of FIG. 5;  
         [0014]    [0014]FIG. 7 is the back plan view of the reciprocating blade mount of FIG. 5;  
         [0015]    [0015]FIG. 8 is a top plan view of the reciprocating blade mount of FIG. 5;  
         [0016]    [0016]FIG. 9 is a side plan view of the right reciprocating blade mount;  
         [0017]    [0017]FIG. 10 is a front plan view of the gear-driven cam;  
         [0018]    [0018]FIG. 11 is a cross-sectional view of the gear-driven cam through lines  11 - 11  of FIG. 10;  
         [0019]    [0019]FIG. 12 is the back plan view of the gear-driven cam of FIG. 10;  
         [0020]    [0020]FIG. 13 is a side plan view of the guide for the reciprocating blade mounts;  
         [0021]    [0021]FIG. 14 is a front plan view of the guide of FIG. 13 shown partially in section;  
         [0022]    [0022]FIG. 15 is a front plan view of the mounting member for the cam of FIGS.  10 - 12 ;  
         [0023]    [0023]FIG. 16 is a cross-sectional view taken through lines  16 - 16  of FIG. 14; and  
         [0024]    [0024]FIG. 17 is a view of another embodiment of a carving knife according to the present invention with one half of the outer housing removed.  
     
    
     SUMMARY OF THE INVENTION  
       [0025]    The objects of the invention have been accomplished by providing an electric carving knife for driving a pair of carving knife blades, where the knife comprises a housing having a front motor receiving section and a rear handgrip section, the handgrip section having a reduced cross-section as compared to the front motor receiving section. A motor is positioned in the front motor receiving section, having a drive shaft extending rearwardly in the general direction as the rear handgrip section. A drive mechanism is connected to the motor drive shaft, and including a gear drive train to impart a reciprocating motion to the blades such that the knife blades are driven asymmetrically. Preferably, the electric carving knife blades are driven 180° out of phase.  
         [0026]    Also preferably, the drive gear train comprises a worm gear attached to and driven by the motor drive shaft, a cam member drive by the worm gear, and reciprocating blade mounts which are driven by the cam member. The worm gear is attached to the motor drive shaft and rotates about a longitudinal axis. The cam member is comprised of a spur gear meshing with the worm gear, and rotates about an axis transverse with the longitudinal axis. The cam member includes cam lobes positioned on opposite sides of the spur gear, the cam lobes being eccentric relative to the transverse axis and 180° out of phase relative to each other. The reciprocating blade mounts are substantially L-shaped to include an upstanding foot portion and an elongate leg portion, the upstanding foot portions having elongate slots which overlap the cam lobes. The elongate leg portions of the reciprocating blade mounts extend forwardly and include blade mounting sections situated adjacent the forward section of the front motor receiving section, and the front motor receiving section including an access opening, accessing the blade mounting sections. The front motor receiving section includes upper arcuate outer walls profiled to surround the motor, and tapered walls surrounding the reciprocating blade mounts. The handgrip section includes a battery receiving cavity for the receipt of a battery.  
         [0027]    In another embodiment of the invention, the motor has a drive shaft extending forwardly in the direction of the knife blades. The drive gear train is situated forward of the motor and includes substantially L-shaped reciprocating blade mounts having rearwardly facing elongate leg portions. The elongate leg portions have blade mounting sections situated adjacent the rearward section of the motor receiving section as previously described.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    With reference first to FIG. 1, a battery-powered carving knife is shown generally at reference numeral  2  which includes a housing member  4  having a power switch at  6  to provide power to reciprocating knife blades shown at  8 . The housing  4  generally includes a front motor receiving section  10  and a handgrip section at  12 . With respect to FIG. 2, the carving knife  2  further generally comprises a motor at  14 , driven by battery  16 , which, as mentioned before, has intermediate power switch  6  for engaging or disengaging the motor  14 . In the preferred embodiment of the invention, battery  16  is a nickel metal hydroxide (Ni—MH) battery pack; six batteries total, with three stacks of two batteries. The carving knife  2  further includes a cam member  18 , and reciprocating blade mounts at  20  which reciprocate within guide members  22 . Cam  18  is held in place about a rotational axis by a bracket  24 .  
         [0029]    With reference now to FIGS. 1 and 2, the housing member  4  will be described in greater detail. As shown in FIG. 1, the housing  4 , and in particular the motor receiving section  10 , includes outer arcuate surfaces  26  profiled so as to receive motor  14 . The housing  4  also includes tapered walls  28  which neck down to define a narrower section of the housing  4  which are profiled so as to receive the reciprocating blade mounts  20  as well as end section  30  of the knife  8 . As shown best in FIG. 1, an opening  32  is provided at the front end of the housing  4  to receive the reciprocating blades  8 . As shown in FIG. 2, the housing  4  includes a battery receiving section  34  within handgrip section  12  so as to retain battery  16 . It should be appreciated that the handgrip section  12  is of a reduced cross section as compared to the motor receiving section  10 .  
         [0030]    With respect now to FIGS.  3 - 16 , the drive train of the carving knife  2  will be described in greater detail. As shown in FIG. 3, motor  14  includes a drive shaft  40  which extends along a generally longitudinal axis and projects rearwardly towards battery  16 . Drive shaft  40  includes a press fit worm gear  42  having a helical tooth at  44 . With respect now to FIGS.  5 - 8 , reciprocating blade mount  20  will be described in greater detail. The reciprocating blade mount  20  is substantially L-shaped, as shown in either of FIG. 5 or  7  to include an upstanding foot portion  50  and an elongate leg portion at  52 . The upstanding foot portion  50  includes an elongate slot at  54  as will be described in further detail herein. The elongate leg portion  52  includes a blade receiving area at  56  having a slot  60  within the reciprocating blade mount  20 . Leg portion  52  further includes spacing lugs at  58 ,  59  which will be described in greater detail. As shown in FIG. 7, the reciprocating blade mount  20  includes a back surface  62  which is substantially flat so as to cooperate with the guide member  22 , as will be described herein. Finally, the blade mount  20  includes a tapered section at  64 , which transitions from the elongate leg  52  to the foot section  50 . Foot section  50  also includes a bearing surface at  66  to cooperate with cam member  18 , as more fully discussed herein.  
         [0031]    With reference now to FIG. 9, the cooperating and right blade mount  20 ′ is shown which is a mirror image of blade mount  20 . Blade mount  20 ′ includes a foot portion  50 ′ connected to an elongate leg portion  52 ′. The foot portion  50 ′ has an elongate slot and a blade receiving area at  56 ′ including a blade receiving slot  60 ′. The leg portion  52 ′ further includes spacing lugs  58 ′. It should be appreciated from a comparison of FIGS. 5 and 9, that the spacing lugs  58 ,  58 ′ are profiled in a cooperating manner such that when the two legs  52 ,  52 ′ are placed against each other, the single spacing lug  59  of leg  52  is positioned intermediate the two spacing lugs  58 ′ of the leg  52 ′; and the single lug  59 ′ of the leg  52 ′ is spaced intermediate the two lugs  58  on leg  52 .  
         [0032]    With respect now to FIGS.  10 - 12 , the cam member  18  will be described in greater detail. As shown first in FIG. 10, the cam member  18  includes a central spur gear portion  70 , having gear teeth  72 . The cam member  18  includes a central opening  74  about which it can rotate and cam lobes  76  and  78  being positioned on opposite sides of the spur gear member  70 . As shown in FIGS. 10 and 12, cam lobes  76  and  78  are eccentric relative to the central opening  74 , and in the preferred embodiment of the invention are 180° out of phase of each other. As shown in FIGS.  10 - 12 , the central spur gear portion includes outer surface portions  70   a  and  70   b , which cooperate with the blade mounts as more fully described herein.  
         [0033]    With reference now to FIGS. 13 and 14, the guide member  22  for the reciprocating blade mount is shown in greater detail. The guides  22  include an outer peripheral bearing ring portion  80  having a generally rectangular internal surface  82  and outer locating lugs at  84 . With reference now to FIGS. 15 and 16, bracket  24  will be described in greater detail. Bracket  24  includes a back plate portion  90  having a central opening at  92  with mounting holes at  94 . The bracket  24  further includes two mounting arms at  96  having a pin receiving opening  98  in each arm.  
         [0034]    With the various components as described above, the assembly of the carving knife  2  will be described as follows. The cam member  18  is first positioned between the two cooperable reciprocal blade mounts  20 ,  20 ′ such that the cam lobes  76 ,  78  are situated in corresponding elongate slots  54 ,  54 ′ as best shown in FIG. 4. It should be appreciated that the blade mounts  20 ,  20 ′ are profiled, through tapered section  64 , to overlap the cam member  18 , and the lugs  58 ,  59 ,  58 ′,  59 ′ interdigitate as described above. The guides  22  for the reciprocal blade mounts  20 ,  20 ′ may now be slidably received over an end thereof. The bracket  24  may be assembled to the cam by aligning apertures  98  of arms  96  (FIG. 15) with the central opening  74  (FIGS.  10 - 12 ) of the cam and slidably receiving a pin  100  (FIG. 4) through the arms  96  and through the central opening  74 . The combination of the above-described assembly may now be positioned within the housing  4 , together with the motor  14 , such that the helical tooth  44  of the worm gear  42  meshes with the gears  72  of the cam member  18 . Furthermore, guides  22  are positioned with their locating lugs  84  in corresponding locating slots  110  in the housing. It should be appreciated that the battery compartment  34  would include a contact mechanism (not shown) which would be wired to the motor member  14  together with the intermediate switch  6  as is well known in the art. It should also be appreciated that the handgrip section  12  of the housing  4  would include an end cap such as  120  to slidably receive a battery  16  therein. The assembly would be completed by enclosing the assembly described above with the housing half which forms part of the housing assembly  4 .  
         [0035]    As assembled, the battery-powered carving knife operates as follows. When the switch  6  is positioned in the ON position, the motor shaft  40  is driven which in turn drives worm gear  42 . This causes engagement of the tooth  44  and teeth  72  of the cam member  18 . Cam member  18  rotates about pin  100  causing eccentric cam lobes  76 ,  78  to eccentrically rotate around pin  100  within cooperating elongate slots  54 ,  54 ′, thereby causing a reciprocation of the reciprocating blade mounts  20 ,  20 ′. As mentioned above, the reciprocating blade mounts  20 ,  20 ′ reciprocate out of phase by 180°. FIG. 3 shows the end portion  30  of the blade  8  positioned in the gripping slot  56  so as to be held in place.  
         [0036]    It should be appreciated then that the above-mentioned design is both very ergonomically designed as well as compact and lightweight. As best shown in FIG. 2, as the drive shaft of the motor  14  extends rearwardly, this allows the reciprocating blade mounts to reciprocate beneath the motor such that the length of the motor receiving compartment  10  needs only to be the length of the reciprocating blade mounts  20 ,  20 ′, not the addition of the motor  14  and the reciprocating blade mounts  20 ,  20 ′. Moreover, as the motor  14  and the reciprocating blade mounts  20 ,  20 ′ are positioned forward of the handgrip member  12 , the weight of the motor  14 , and the reciprocating blade mounts  20 ,  20 ′ cause a moment in the same direction as that needed to carve the item to be cut assisting the blades  8  in the carving operation.  
         [0037]    In another embodiment of the invention, shown in FIG. 17, a battery-powered carving knife  202  is shown having a housing member  204  which is similar to housing member  4  as previously described. In this embodiment, the motor  14  is oriented so that the drive shaft  40  extends generally longitudinally projecting forwardly away from the handgrip section  212 . The drive train is also repositioned to the forward section of the motor receiving section.  
         [0038]    As described in the previous embodiment, the motor drive shaft includes the press fit worm gear  42  for driving cam member  18 . Cam member  18  includes a central spur gear portion  70 , which is meshed with the worm gear  42  as previously described. The cam member  18  has a central opening  74  about which it rotates and cam lobes  76  and  78  positioned on opposite sides of the central spur gear  70 . Again, cam lobes  76  and  78  are eccentric to the opening  74  and are preferably oriented so that they are 180° out of phase with each other.  
         [0039]    Similar to the previously described embodiment, L-shaped reciprocating blade mounts  220  are provided which include an upstanding foot portion  250  having an elongate slot (not shown) which is identical to that in the foot portion  50  of blade mount  20 . Blade mount  220  also includes an elongate leg portion  252 , and a tapered section, which is hidden in FIG. 17, that transitions from the elongate leg portion  252  to the foot portion  250 . The elongate leg portion  252  includes a blade receiving area  256 . As shown in FIG. 17, the blade mount  220  in this embodiment is oriented so that the elongate leg portion  252  extends rearwardly in the direction of the knife&#39;s grip section  212 . So oriented, it will be appreciated that in this embodiment, the end section  230  of knife blade  208  is slightly longer than that of the previous embodiment so as to be properly engaged in the blade receiving area  256 , which in this embodiment extends into the rear portion of the front motor receiving section. In other respects, the blade mount  220  is identical to that of the embodiment previously described.  
         [0040]    Assembly is similarly achieved with the cam lobes  76 , and  78  being received in the elongate slots of a cooperating pair of blade mounts. As in the previously described embodiment, a bracket  24  is provided to complete the assembly of the cam member  18  and blade mount  220 , and for positioning the assembly within the housing. Guide members  222  are also provided for locating the elongate leg portion  252  of the blade mount  220  within the housing  204  using locating slots  210 .  
         [0041]    Operation of this embodiment of the invention is identical to that of the first described embodiment achieving the same ergonomic and operational benefits previously described. This embodiment maintains the positioning of the reciprocating blade mounts beneath the motor, maintaining the brevity of the motor receiving compartment.  
         [0042]    Advantageously, in either of the embodiments of FIG. 2 or  17 , the motor  14  and blade mounts, either  20  or  220 , are positioned within the housing  4  or  204 , such that they longitudinally overlap. This allows for a reduction in the overall length of the knife as described above. In either case, this also places the weight of the motor and blades forward of the handle, which accounts for a moment in a direction which will assist cutting or carving.