BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional side view of a handheld rotary cutter constructed in accordance with one embodiment of the present invention, with the blade actuator in a retracted position;
FIG. 2 is a sectional side view of the handheld rotary cutter of FIG. 1, with the blade actuator in an extended position; and
FIG. 3 is an exploded view showing the components of the rotary cutter of FIGS. 1 and 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1-3 show a rotary cutter 10 constructed in accordance with the principles of the present invention. The rotary cutter 10 includes a body 12 having a cylindrical head 13. The body 12 can take a variety of forms. For example, the body 12 can include separable but substantially identical right and left handles 16 and 18 which can either surround or both be on one side of a cutting blade 20 and be joined in part by a handle insert 17. Other arrangements and configurations of the body 12 would also be understood to be potentially implemented by those skilled in the art.
A trigger 14 is rotatably coupled to the body 12 at a rearward pivot point 22. In the embodiment shown in FIGS. 1-3, this is accomplished by using a plastic or metallic rearward pivot pin 24 to couple the trigger 14 to the body 12.
In addition to the trigger 14, a blade actuator 26 is also rotatably coupled to the body 12. As shown in FIGS. 1 and 2, the blade actuator 26 is coupled to the body 12 at a forward pivot point 28, using a plastic or metallic forward pivot pin 30 in various embodiments of the invention. The blade actuator 26 also includes a region to which the cutting blade 20 is attached. The cutting blade 20 can be placed on a blade axle 31 removably connected to the blade actuator 26, and a hub cup 32, wave spring 34 and hub cap 36 can cooperatively be used to selectively secure the cutting blade 20 in place. In the embodiment shown in FIGS. 1-3, a nut 37 is positioned within the body 12 and is used to tighten the blade axle 31 so that the cutting blade 20 remains secured to the body 12. The rotary cutter 10 can be sized for various cutting blades, including but not limited to 45 mm and 60 mm blades.
As shown in FIGS. 1 and 2, the trigger 14 and the blade actuator 26 interact as follows. An actuator pin 27 slidably engages a guide structure 38 formed on the trigger 14. In this particular embodiment of the invention, the guide structure 38 comprises a slot within which an actuator pin 27 moves. It is also possible, however, for the guide structure 38 to take other forms. The guide structure 38 is located at an end of the trigger 14 substantially opposite the rearward pivot point 22. The actuator pin 27 can either be formed as part of the blade actuator 26, or it could be a separate component which is coupled to the blade actuator 26. When the end of the trigger 14 closest to the cutting blade 20 (the forward end) moves towards the top of the rotary cutter 10 (i.e., when the trigger 14 rotates in a clockwise direction in FIGS. 1 and 2), the guide structure 38 “pushes” the actuator pin 27 upwards as well. As a result, movement of the trigger 14 causes a reciprocal movement in the blade actuator 26 (i.e., the blade actuator 26 moves in a counter-clockwise direction in FIGS. I and 2).
The operation of the rotary cutter 10 is generally as follows. FIG. 1 shows the rotary cutter 10 in a “retracted” position, with the cutting blade 20 retracted and its edge 60 not exposed. To extend the cutting blade 20, the user grasps the trigger 14, pulling the trigger 14 upwards towards the top of the rotary cutter 10. This action causes the guide structure 38 of the trigger 14 to act against the actuator pin 27, causing the rear portion of the blade actuator 26 to also move upward. This results (in terms of FIGS. 1 and 2) in a counter-clockwise rotation of the blade actuator 26 about the forward pivot point 28, causing the forward portion of the blade actuator 26 to move downward. As the cutting blade 20 is coupled to the forward portion of the blade actuator 26, the cutting blade 20 also moves downward in response to this action. As a result, the cutting blade edge 60 becomes exposed (as represented in FIG. 2), allowing a user to cut materials as necessary using the cutting blade 20. When the cutting action is taking place, the forces applied to the rotary cutter 10 from the cutting surface, such as a cutting mat, are transferred from the blade actuator 26 to the trigger 14 where the blade actuator 26 contacts a trigger finger 41. These forces are ultimately transferred to the rearward pivot point 22 and do not bear directly against the user's hand.
When a user wishes to retract the cutting blade 20, the user simply loosens his or her grip on the trigger 14. The relieving of force on the trigger 14 allows a biasing member 62, a compression spring in one embodiment of the invention, to bias the trigger 14 away from the upper surface of the body 12. The biasing member 62 is configured to contact a biasing abutment 64 on the trigger 14 and a upper biasing surface 66 on the body 12. Once the user's grip on the trigger 14 has been released, the rotary cutter 10 returns to the retracted position shown in FIG. 1.
In addition to the above, a locking member 48 can be used to selectively lock the cutting blade 20 in a certain position. As is shown in FIGS. 1-3, the blade actuator 26 includes a locking region 50 that is sized to interact with the locking member 48, which also fits within a locking member receptacle 52 of the body 12. As is most clearly shown in FIG. 3, the locking member 48, according to one embodiment of the invention, includes an abutment 54 which is sized to selectively match a pair of abutment openings 56 in the locking region 50. In the embodiment depicted in FIGS. 1-3, the user can press the locking member 48 from either side of the body 12 to move the abutment 54 into and/or out of engagement with one of the abutment openings 56, selectively locking and unlocking the position of the blade actuator 26 and therefore the cutting blade 20. By using the locking member 48, the user obtains the added benefit of not having to keep applying force to the trigger 14 to keep the cutting blade 20 in an extended position. The locking member also adds to the overall stability of the rotary cutter 10, as the likelihood of the cutting blade 20 moving during a cutting operation is greatly reduced.
The foregoing description of embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the present invention. The embodiments were chosen and described in order to explain the principles of the present invention and its practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated.
Patent Application
20080010839
