Abstract:
A log splitting machine having a disk-like blade rotatable about an axis and able to split a log in a single 360° rotation about said axis. The blade has two parts, each of which performs a different function. The first part of the blade has a spiral-shaped cutting edge designed to sufficiently penetrate into an end of a log to be split so as to form a lengthwise crack in the log. The second part of the blade has a widening edge designed to separate the log into two pieces along the lengthwise crack with further rotation of the blade. The log splitting machine also includes: an adjustable backstop for accommodating logs of different length; a frame for supporting the blade, log and adjustable backstop; an electric motor for powering the blade through a 360° rotation; and a hood covering the blade and motor, and a deadman control switch for increased operator safety.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to log splitting machines and more particularly to a blade for such machines which is rotatable about an axis and able to split a log in a single 360° rotation about said axis. 
     2. Description of the Prior Art 
     Logs must be split in order to be effectively and economically used as firewood. The majority of motorized log splitting machines known today are designed to operate by forcing a log against a wedge with a ram. Typically, the ram is hydraulically driven and the motor is gasoline powered. Such log splitting machines exhibit a number of disadvantages. For example, the operator of such a machine frequently must steady the log to be split which creates the possibility of a trapped hand between the log and the ram or wedge when the power is applied. The ram in these log splitting machines usually requires about twenty seconds to cycle from a retracted position to an advanced position and back again. Also, these machines are often long and heavy due to the length and weight of the ram. Gasoline powered log splitters have the further undesirable features of being loud and air polluting. 
     Thus, there presently exists a genuine need for a safe, effective, fast, quiet, pollution-free, relatively small, easy to use, automatic log splitting machine. 
     SUMMARY OF THE INVENTION 
     The present invention satisfies these needs by providing a log splitting machine with a unique functional design. Central to the present invention, is a blade which is rotatable about an axis and able to split a log in a single 360° rotation about said axis. The blade comprises a disk-like member having two parts, each of which performs a different function. The first part of the disk-like member has a spiral-shaped cutting edge. The spiral-shaped cutting edge is designed to sufficiently penetrate into an end of a log to be split so as to form a lengthwise crack in the log. The second part of the disk-like member has a widening edge and is subsequent to, and integral with, the first part. With further rotation of the blade the widening edge is designed to separate the log into two pieces along the lengthwise crack. 
     Along with the unique blade, the present invention contemplates: an adjustable backstop for accommodating logs of different length; a frame for supporting the blade, log and adjustable backstop; an electric motor for powering the blade through a 360° rotation; and a hood covering the blade and motor, and a deadman control switch for increased operator safety. 
     A principle object of the present invention is the provision of a log splitting blade rotatable about an axis and able to split a log in a single 360° rotation about said axis. 
     Another object of the present invention is the provision of a relatively fast operating log splitting machine which increases an operator&#39;s log splitting productivity. 
     A further object of the present invention is the provision of such a log splitting machine which is relatively small, easy to use, and automatic. 
     A still further object of the present invention is the provision of such a log splitting machine which is quiet, pollution-free and operable in an enclosed space. 
     Yet another object of the present invention is the provision of such a log splitting machine which is also safe to use and easy to move. 
     Still another object of the present invention is the provision of such a log splitting machine which readily accommodates logs of different lengths and requires less frequent cutting edge sharpening. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is an elevational view depicting major functional elements of the present invention. 
     FIG. 1A is a top plan view of the embodiment of FIG. 1 showing the blade of the present invention partially rotated into the log so as to form a lengthwise crack in the log. 
     FIG. 1B is a top plan view of the embodiment of FIG. 1 showing the blade of the present invention further rotated into the log so as to separate the log into two pieces along the lengthwise crack. 
     FIG. 2 is a perspective view of the blade of the present invention. 
     FIG. 3 is an elevational view of the blade of the present invention. 
     FIG. 4 is a top plan view of the blade of the present invention. 
     FIG. 5 is a perspective view of an alternate embodiment of the blade of the present invention. 
     FIG. 6 is a perspective view of the log splitting machine of the present invention. 
     FIG. 7 is an enlarged partial view of the log splitting machine of the present invention. 
     FIG. 8 is an elevational view of the log splitting machine of the present invention showing an optional storage/operation position in phantom. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The function of major elements of the present invention will now be described with reference to FIGS. 1, 1A and 1B. In FIG. 1, a disk-like blade, generally denoted as 10, having an axis of rotation 12 is shown at one end of frame 16. A log 14 is positioned on frame 16 so as to have one end in contact with blade 10 and an opposite end in contact with an adjustable backstop 18. As shown in FIG. 1A, and as discussed in more detail below, a first part 20 of blade 10 sufficiently penetrates into log 14 with clockwise rotation of blade 10 so as to form a lengthwise crack 15 in log 14. A second part 22 of blade 10, subsequent to and integral with first part 20, follows first part 20 into log 14 with further clockwise rotation of blade 10, and separates log 14 into two pieces 14a &amp; 14b along lengthwise crack 15, as shown in FIG. 1B. The present invention thus accomplishes the splitting of a log with only one 360° rotation of blade 10. 
     A preferred embodiment of blade 10 is shown in perspective in FIG. 2. The first part 20 encompasses approximately two thirds of blade 10 and comprises a cutting portion having a cutting edge 24. As depicted in FIG. 3, cutting edge 24 has a radial length R c  from the axis of rotation 12 of blade 10 which increases in a direction opposite (counter clockwise) to the direction of rotation of the blade (clockwise) so as to give first part 20 of blade 10 a spiral-shaped form. The width W c  of first part 20 remains substantially constant as indicated in FIG. 4. 
     Referring back to FIG. 2, it can be observed that the second part 22 encompasses approximately one-third of blade 10 and comprises a wedge portion having a widening edge 26. Widening edge 26 has a substantially constant radial length R w  from the axis of rotation 12 of blade 10 as shown in FIG. 3. It can be seen with reference to FIGS. 2 &amp; 4 that widening edge 26 increases in width in a direction opposite (counter clockwise) to the direction of rotation of the blade (clockwise). 
     In practice, blade 10 will be connected to an axle 30 as shown in FIG. 2. The connection of blade 10 to axle 30 may be accomplished by any known means. In the preferred embodiment, a standard key arrangement is used to attach blade 10 to axle 30. As shown, a boss 32 is preferably added to both sides of blade 10. Boss 32 provides a longer key way for the connection of blade 10 to axle 30 and also serves to give radial support to blade 10. Also shown in FIG. 2 is a relatively small notched portion 28 forming a 90° cutout between the end of second part 22 and the beginning of first part 20. This cutout provides for ready, initial placement of log 14 against blade 10. 
     By way of example, blade 10 may have the following dimensions: a first part radial length R c  which increases from an initial length of 3 inches to a final length of 6 inches; a second part radial length R w  of 6 inches; a constant first part width W c  of 1/2 inch; a second part wedge width W w  which increases from an initial width of 1/2 inch to a final width of 41/2 inches; and bosses as discussed above, of 3 inches in radius on either side of blade 10. 
     An important and unexpected side benefit of the present invention was realized during prototype testing. Blade 10 has successfully split numerous cords of wood without requiring sharpening of cutting edge 24. The greatest amount of work done by log splitting machine 40 (see FIG. 6) occurs within the initial 1/3 rotation of blade 10, prior to the formation of lengthwise crack 15 in log 14 (see FIG. 1B). Once lengthwise crack 15 forms, dulling pressures on cutting edge 24 dissipate and further rotation of blade 10 in log 14 will tend to maintain the sharpness of cutting edge 24. Preferably, blade 10 will be forged from either a hard or cold rolled steel. 
     An alternate embodiment of blade 10 is shown in FIG. 5. In this embodiment, second part 22 of blade 10 has a constant radial length R w  as in the preferred embodiment. However, the widening portion W w  of second part 22 extends over a greater radial length R w  of second part 22, as shown in FIG. 5. In the preferred embodiment, as noted above, second part 22 has only widening edge 26 since this is sufficient to successfully separate log 14 into two pieces along lengthwise crack 15. 
     The preferred embodiment of the log splitting machine of the present invention, generally denoted as 40, is shown in FIG. 6. Log splitting machine 40 has a frame body 44 upon which a log to be split is placed. Blade 10 is located at one end of frame body 44 and adjustable backstop 18 is located near the other end. A hood 42 covers most of blade 10 and the means for rotating blade 10. A T-shaped cutout 61 in frame body 44 accomodates the rotation of blade 10. Adjustable backstop 18 is horizontally reciprocally operable between a forward and a retracted position within an adjustment range defined by frame cut-out 48 as needed depending upon the length of the log to be split. Additionally, adjustable backstop 18 preferably has an angled rasp-like surface 46 facing and contacting the log to be split. The angled rasp-like surface 46 allows an operator to split logs of varying lengths without adjusting backstop 18 for each log to be split. 
     Frame body 44 is supported at one end by a standard wheel assembly generally denoted as 50. The wheel assembly 50 has legs 52 connected to a transverse axle 56 which has wheels 54 at opposite ends thereof. Frame body 44 is supported at the other end by a fixed leg 58 having a V-shape for increased support strength and stability of log splitting machine 40. A handle 60 is attached to the same end of frame body 44 as fixed leg 58. Handle 60 is provided to facilitate movement of log splitting machine 40 by the operator either to a different location or to a different storage/operation position, as described in more detail below. Lastly, it can be observed from FIG. 6 that a U-shaped bar 62 is attached to the open portion of hood 42. Should blade 10 become caught in a log being split, the operator may reverse rotation of blade 10 causing the log to lift up and impact against U-shaped bar 62 and in so doing free blade 10. 
     Referring to FIG. 7, an enlarged, cut-away partial view of log splitting machine 40 is shown. An operator may cycle blade 10 once by pressing switch 64 which will result in energizing the means for rotating blade 10. At one end of axle 30 is a cam 73 which is engaged by a cam follower 71. Upon completion of one cycle, cam follower 71 causes the means for rotating blade 10 to be de-energized. Switch 64 will preferably contain a dead man control feature and may be located in any appropriate position on frame body 44 or may be a hand held or foot controlled device. In the preferred embodiment of the present invention, the means for rotating blade 10 will be electrically driven. However, it should be understood that alternate rotating means, such as a gasoline powered engine, may be used without departing from the spirit of the present invention. 
     Preferrably, an 110-V electric motor 66, having approximately a 1 H.P., 1725-RPMs rated output, will be energized by inserting plug 65 into any standard household outlet. The 1725 RPMs rated output of 110-V electric motor 66 will be reduced via a standard gear box 68 to approximately 6 RPMs. The preferred rotational speed of 6 RPMs will allow blade 10 to complete a 360° cycle in approximately 10 seconds, a fast yet acceptable and safe operating speed. The 6 RPMs output of gear box 68 will be transferred to axle 30 of blade 10 via a dual drive chain assembly 70. The combination of blade 10 and axle 30 is held in place by traditional pillow blocks with bearings 72 on each side of blade 10. Pillow blocks with bearings 72 are secured by bolts 74 to body frame 44. 
     The versatility of log splitting machine 40 is illustrated in FIG. 8. The log splitting machine may be operated or stored in either a horizontal or vertical position. Vertical positioning of log splitting machine 40 offers the advantages of occupying less storage space and of not requiring the operator to lift the log as high as when the log splitting machine is used in a horizontal position. Lastly, as noted earlier and as shown in the horizontal positioning of log splitting machine 40 in FIG. 8, a rasp-like surface 46 on backstop 18 allows logs of varying length to be split without requiring the operator to continually adjust backstop 18. 
     It will be noted that this invention fully meets the objectives set forth. A log splitting blade rotatable about an axis is provided which may be used to split a log in a single 360° rotation about said axis. Also, it will be noted that the log splitting machine of the present invention is faster and smaller than traditional log splitting machines which utilize a ram. Additionally, it is evident that the electrically driven log splitting machine of the present invention is relatively quiet and pollution free. Lastly, it will be observed that the log splitting machine of the present invention is compact, versatile, safe to use, easy to move and requires less frequent blade sharpening. 
     Although one embodiment has been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiment discussed but is capable of numerous rearrangements, modifications, and substitutions without departing from the scope of the invention. For example, the blade might, under appropriate circumstances vary in size and dimensions from those given, or the adjustable backstop might be of a different construction. Other changes, within the scope of the invention as defined by the appended claims, will suggest themselves to those versed in this art.