Patent Publication Number: US-11034049-B2

Title: Kinetic log splitter having automatic brake mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present specification claims priority to U.S. Provisional Patent Application No. 62/669,219, filed May 9, 2018. 
    
    
     TECHNICAL FIELD 
     The present specification generally relates to log splitters, and more particularly, kinetic log splitters having automatic brake mechanisms. 
     BACKGROUND 
     It has been known to provide log splitters that split logs into smaller pieces for convenience. The previously known log splitters utilize kinetic energy stored in a flywheel to linearly displace a ram towards a stationary splitter. The log is placed between the ram and the stationary splitter. A motor rotates a flywheel operatively connected to a gear shaft such that rotation of the flywheel rotates the gear shaft. The ram includes a plurality of teeth that engages with gear teeth of the rack to linearly displace the ram forward towards the splitter. However, in the previously known log splitters, the gear shaft continues to rotate due to the rotation of the flywheel by the motor even when the linear displacement of the ram is stopped or jammed. 
     As such, the continued rotation gear shaft, when the ram is stopped, leads to a decrease is useful life of the ram and the gear shaft. Specifically, once the ram is inhibited from linearly displacing forward, the gear shaft continues to rotate with the gear teeth engaged with the plurality of teeth of the ram thereby causing wear and/or damage to the plurality of teeth of the ram and the gear teeth of the gear shaft. 
     Accordingly, there is a need for a kinetic log splitter having an automatic braking mechanism which is configured to inhibit rotation of the gear shaft upon stopping of the forward linearly displacement of the ram towards the stationary splitter. 
     SUMMARY 
     In one embodiment, a kinetic log splitter includes a frame, a splitter, a gear shaft, a drive assembly, a push plate, a rack, and an automatic brake mechanism. The splitter is coupled to the frame. The gear shaft is rotatably coupled to the frame. The drive assembly is configured to rotate the gear shaft. The push plate is slidably coupled to the frame. The rack is operatively coupled to the push plate. The rack is configured to engage with the gear shaft to linearly displace the push plate towards the splitter. The automatic brake mechanism is configured to automatically inhibit rotation of the gear shaft by the drive assembly upon application of a pressure/tonnage or force that exceeds a predetermined tonnage on the push plate. 
     In another embodiment, a kinetic log splitter includes a frame, a splitter, a gear shaft, a motor, a flywheel, a push plate, a rack, and a slip disk assembly. The splitter is coupled to the frame. The gear shaft is rotatably coupled to the frame. The motor is configured to rotate an output shaft. The flywheel is operatively coupled to the output shaft of the motor. The push plate is slidably coupled to the frame. The rack is operatively coupled to the push plate. The rack is configured to engage with the gear shaft to linearly displace the push plate towards the splitter. The slip disk assembly is configured operatively couple the flywheel to the gear shaft so as to transmit rotational force from the flywheel to the gear shaft. The slip disk assembly is configured to automatically inhibit rotation of the gear shaft by the flywheel upon exceeding a predetermined rotational force between the flywheel and the slip disk assembly. 
     These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description, in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
         FIG. 1  schematically depicts a perspective view of a kinetic log splitter having an automatic braking mechanism according to one or more embodiments shown or described herein; 
         FIG. 2  schematically depicts a partial enlarged view of the kinetic log splitter having the automatic braking mechanism of  FIG. 1  according to one or more embodiments shown or described herein; 
         FIG. 3  schematically depicts a partial enlarged view of the kinetic log splitter of  FIG. 1 , according to one or more embodiments shown or described herein; and 
         FIG. 4  schematically depicts a partial exploded perspective view of the automatic brake mechanism of  FIG. 1 , according to one or more embodiments shown or described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Kinetic log splitters according to the present specification include a frame, a splitter, a gear shaft, a drive assembly, a push plate, a rack, and an automatic brake mechanism. The splitter is coupled to the frame. The gear shaft is rotatably coupled to the frame. The drive assembly configured to rotate the gear shaft. The push plate is slidably coupled to the frame. The rack is operatively coupled to the push plate. The rack is configured to engage with the gear shaft to linearly displace the push plate towards the splitter. The automatic brake mechanism is configured to automatically inhibit rotation of the gear shaft by the drive assembly upon exceeding a predetermined tonnage on the push plate 
     The kinetic log splitters of the present disclosure inhibit the continued rotation of the gear shaft by the drive assembly when the linear displacement of the push plate and the rack is obstructed. Specifically, the automatic brake mechanism is configured to inhibit (i.e. reduce and/or stop) transmission of a rotational force from the drive assembly to the gear shaft upon exceeding a predetermined tonnage and/or force on the push plate. The automatic inhibiting of the transmission of rotational force to the gear shaft when the linear displacement of the rack is obstructed prevents wear and damage to the gear shaft and the rack, specifically, damage to gear teeth of the gear shaft due to a shock stress. 
     Various embodiments of kinetic log splitter are described in detail below with reference to the appended drawings. 
     As used herein, the term “longitudinal direction” refers to the forward-rearward direction of the log splitter (i.e., in the +/−Z-direction as depicted). The term “lateral direction” refers to the cross-vehicle direction of the log splitter (i.e., in the +/−X-direction as depicted), and is transverse to the longitudinal direction. The term “vertical direction” refers to the upward-downward direction of the log splitter (i.e., in the +/−Y-direction as depicted). As used herein, “upper” and “above” are defined as the positive Y direction of the coordinate axis shown in the drawings. “Lower” and “below” are defined as the negative Y direction of the coordinate axis shown in the drawings. Further, the terms “outboard” as used herein refers to the relative location of a component with respect to a centerline. The term “inboard” as used herein refers to the relative location of a component with respect to the centerline. Because the log splitter structures may be generally symmetrical about the centerline, the direction to which use of terms “inboard” or “outboard” and refer may be mirrored about the centerline when evaluating components positioned along opposite sides. 
     Referring to  FIG. 1 , a log splitter is generally illustrated at  10 . The log splitter  10  is a kinetic log splitter that stores kinetic energy and operates to release the stored kinetic energy to split logs. The log splitter  10  includes a frame  12 , a splitter  14 , a gear shaft  16 , a drive assembly  18 , a push plate  20 , a rack  22 , and an automatic brake mechanism  24 . 
     Referring to  FIGS. 1 and 4 , the frame  12  includes an elongated frame member  30 , a pair of tables  31 , a front strut  32 , a rear strut  34 , and a pair of wheel  36  rotatably coupled to the rear strut  34 . The frame member  30  includes a front end  30 A and an opposite a rear end  30 B. The pair of tables  31  are secured to the frame member  30 . The front strut  32  is positioned adjacent the front end  30 A of the frame member  30 . The rear strut  34  is positioned adjacent the rear end  30 B of the frame member  30 . The frame member  30  includes a top wall  38 , a bottom wall  40 , and a side wall  42  that extends between the top wall  38  and the bottom wall  40 , such that the frame member  30  has a generally I-shaped cross-sectional shape. The top wall  38  includes a pair of side edges  38 A that are spaced apart from the side wall  42 . A pair of flanges  46  extend upwardly from the frame member  30 . Each of the pair of flanges  46  includes an opening  48 . 
     The splitter  14  is fixedly secured to the frame member  30 . The splitter  14  extends upwardly in the vertical direction from the top wall  38  of the frame member  30 . The splitter  14  is positioned adjacent the front end  30 A of the frame member  30 . The splitter  14  is formed as a wedge that tapers rearwardly in the longitudinal direction to an edge  14 A. The edge  14 A of the splitter  14  faces the rear end  30 B of the frame member  30 . 
     The gear shaft  16  is rotatably coupled to the frame  12 . The gear shaft  16  includes a plurality of gear teeth  50  disposed between a first end  52  and a second end  54 . The first end  52  and the second end  54  each include a shaped key  55 . The gear shaft  16  is received in the openings  48  of the pair of flanges  46  such that the plurality of gear teeth  50  of the gear shaft  16  is positioned between the pair of flanges  46 , and the first end  52  and the second end  54  extend outwardly through the openings  48  of the pair of flanges  46 . Each of the pair of flanges  46  includes a bearing  56  having an opening  58  on an outer surface thereof. The bearings  56  are mounted to the outer surface of the pair of flanges  46  by a plurality of fasteners. The first end  52  and the second end  54  of the gear shaft  16  extend through the openings  58  of the bearings  56  such that the gear shaft  16  is configured to rotate with respect to the pair of flanges  46 . 
     The drive assembly  18  is configured to supply a rotational force to rotate the gear shaft  16 . The drive assembly  18  includes a motor  60  having an output shaft  62 , a first flywheel  64 , a second flywheel  66 , and a drive belt  68 . The motor  60 , such as an internal combustion engine or an electric motor, outputs a rotational force to the output shaft  62 . The motor  60  is mounted to the rear strut  34  of the frame  12 . In some embodiments, a clutch  70  is optionally provided on the output shaft  62 . The clutch  70  may be configured to operate as a gear reducer to reduce a torque and/or a rotational speed of the output shaft  62  to a preset torque and/or a preset rotational speed. 
     The drive belt  68  couples the output shaft  62  of the motor  60  to the first flywheel  64  such that rotation of the output shaft  62  rotates the first flywheel  64 . In some embodiments, the drive belt  68  engages with the clutch  70  and the first flywheel  64 . The first flywheel  64  and the second flywheel  66  are operatively coupled to the gear shaft  16  by the automatic brake mechanism  24  such that the automatic brake mechanism  24  is configured to transmit a rotational force of the first flywheel  64  to the gear shaft  16 . As such, the first flywheel  64  is configured to transmit rotational force from the output shaft  62  of the motor  60  to the gear shaft  16  through the automatic brake mechanism  24 . 
     The first flywheel  64  includes an inner surface  64 A, an opposite outer surface  64 B, and a central opening  72  that extends between the inner surface  65 A and the outer surface  65 B. The second flywheel  66  includes an inner surface  66 A, an opposite outer surface  66 B, and a central opening  74  that extends between the inner surface  66 A and the outer surface  66 B. In some embodiments, the first flywheel  64  includes a groove  65  provided on an outer peripheral surface, the groove  65  engages with the drive belt  68 . 
     As will be described in greater detail below, the automatic brake mechanism  24  is configured to automatically inhibit rotation of the gear shaft  16  by the drive assembly  18  upon exceeding a predetermined force on the push plate  20 . Specifically, the automatic brake mechanism  24  is configured to inhibit the transmission of rotational force from the first flywheel  64  to the gear shaft  16 . 
     The automatic brake mechanism  24  includes a first slip disk assembly  80  and a second slip disk assembly  82 . The first slip disk assembly  80  operatively couples the first flywheel  64  to the gear shaft  16 , specifically the first end  52  of the gear shaft  16 . The second slip disk assembly  82  operatively couples the second flywheel  66  to the gear shaft  16 , specifically the second end  54  of the gear shaft  16 . The first slip disk assembly  80  and the second slip disk assembly  82  are moveable between an engaged position and a disengaged position. In the engaged position, the first slip disk assembly  80  and the second slip disk assembly  82  are configured to permit the transmission of rotational force from the first flywheel  64  and the second flywheel  66 , respectively, to the gear shaft  16 . In the disengaged position, the first slip disk assembly  80  and the second slip disk assembly  82  are configured to inhibit the transmission of rotational force from the first flywheel  64  and the second flywheel  66 , respectively, to the gear shaft  16 . 
     As the second slip disk assembly  82  is provided with a corresponding structure of the first slip disk assembly  80 , and as operation of the second slip disk assembly  82  corresponds to the operation of the first slip disk assembly  80 , discussion of the second slip disk assembly  82  will be omitted. 
     The first slip disk assembly  80  includes an inner friction plate  84 , an outer friction plate  86 , an inner rotor  88 , an outer rotor  90 , and a plurality of first fasteners  92 . The inner friction plate  84  is mounted to the inner surface  64 A of the first flywheel  64 . The inner friction plate  84  includes a friction surface  84 A opposite the inner surface  64 A of the first flywheel  64 . The outer friction plate  86  is mounted to the outer surface  64 B of the first flywheel  64 . The outer friction plate  86  includes a friction surface  86 A opposite the outer surface  64 B of the first flywheel  64 . 
     The inner rotor  88  includes a central hub  94  that extends outwardly from a rotor surface  88 A of the inner rotor  88 . An opening  96  extends through the central hub  94  of the inner rotor  88 . The opening  96  includes a keyed slot  96 A that corresponds to the shaped key  55  of the first end  52  of the gear shaft  16 . The outer rotor  90  includes a central hub  98  that extends outwardly from a rotor surface  90 A of the outer rotor  90 . An opening  100  extends through the central hub  98  of the outer rotor  90 . The opening  100  includes a keyed slot  100 A that corresponds to the shaped key  55  of the first end  52  of the gear shaft  16 . The engagement of the keyed slot  96 A of the inner rotor  88  and the keyed slot  100 A of the outer rotor  90  with the shaped key  55  of the first end  52  of the gear shaft  16  secures the inner rotor  88  and the outer rotor  90  to the gear shaft  16  such that rotation of the inner rotor  88  and the outer rotor  90  rotates the gear shaft  16 . 
     The central bub  94  of the inner rotor  88  and central hub  98  of the outer rotor  90  include a plurality of corresponding bores  102 . The central hub  94  of the inner rotor  88  and the central hub  98  of the outer rotor  90  are at least partially received within the opening  72  of the first flywheel  64 . The inner rotor  88  and the outer rotor  90  are secured together by the plurality of fasteners  92  that extend through the corresponding bores  102  of the central bub  94  of the inner rotor  88  and central hub  98  of the outer rotor  90  such that the friction surface  84 A of the inner friction plate  84  is in frictional engagement with the rotor surface  88 A of the inner rotor  88  and the friction surface  86 A of the outer friction plate  86  is in frictional engagement with the rotor surface  90 A of the outer rotor  90 . 
     As such, the first flywheel  64  is operatively coupled to the gear shaft  16  by the frictional engagement of the friction surface  84 A of the inner friction plate  84  and the rotor surface  88 A of the inner rotor  88 , and the frictional engagement of the friction surface  86 A of the outer friction plate  86  and the rotor surface  90 A of the outer rotor  90 . Specifically, the first flywheel  64  is configured to permit transmission of rotational force from motor  60  through the drive belt  68  and the output shaft  62  as long as the friction surface  84 A of the inner friction plate  84  is in frictional engagement with the rotor surface  88 A of the inner rotor  88  and the friction surface  86 A of the outer friction plate  86  is in frictional engagement with the rotor surface  90 A of the outer rotor  90 . Specifically, the first flywheel  64  is only connected to the inner rotor  88  and the outer rotor  90  due to the frictional engagement between the friction surface  84 A of the inner friction plate  84  and the rotor surface  88 A of the inner rotor  88  and due to the frictional engagement between the friction surface  86 A of the outer friction plate  86  and the rotor surface  90 A of the outer rotor  90 . Further, the first flywheel is not directly connected to the gear shaft  16 , rather the inner rotor  88  and the outer rotor  90  are secured to the gear shaft  16  and the first flywheel  64  is connected to the inner rotor  88  and the outer rotor  90  by the frictional engagement between the friction surface  84 A of the inner friction plate  84  and the rotor surface  88 A of the inner rotor  88  and the frictional engagement between the friction surface  86 A of the outer friction plate  86  and the rotor surface  90 A of the outer rotor  90 . Accordingly, upon exceeding the predetermined rotational force, the first flywheel  64  is configured to rotate relative to and/or with respect to the inner rotor  88  and the outer rotor  90  such that the first flywheel  64 , when the first slip disk mechanism  80  is in the disengaged position, does not rotate with the gear shaft  16  (i.e. the rotation of the first flywheel  64  when in the first slip disk assembly  80  is in the disengaged position does not transmit a rotational force to the gear shaft  16  to rotate the gear shaft  16  as the first flywheel  64  is not directly connected to the gear shaft  16 ). 
     In the engaged position of the first slip disk assembly  80 , the friction surface  84 A of the inner friction plate  84  and the friction surface  86 A of the outer friction plate  86  are frictionally engaged with the rotor surface  88 A of the inner rotor  88  and the rotor surface  90 A of the outer rotor  90 , respectively. The first slip disk assembly  80  is in the engaged position when a rotational force between the friction surface  84 A of the inner friction plate  84  and the rotor surface  88 A of the inner rotor  88  and between the friction surface  86 A of the outer friction plate  86  and the rotor surface  90 A of the outer rotor  90  is less than a predetermined rotational force. 
     As used herein, the predetermined rotational force is a rotational force at which frictional engagement between the friction surface  84 A of the inner friction plate  84  and the rotor surface  88 A of the inner rotor  88  and the frictional engagement between the friction surface  86 A of the outer friction plate  86  and the rotor surface  90 A of the outer rotor  90  is not overcome. Specifically, at a rotational force less than the predetermined rotational force, the frictional engagement between the friction surface  84 A and the rotor surface  88 A and the frictional engagement between the friction surface  86 A and the rotor surface  90 A causes the rotation of the first flywheel  64  to be transmitted to the inner rotor  88  and the outer rotor  90 , and the rotation of the inner rotor  88  and the outer rotor  90  rotates the gear shaft  16 . 
     Upon exceeding the predetermined rotational force, the first slip disk assembly  80  moves from the engaged position to the disengaged position. In the disengaged position, the first flywheel  64  rotates with respect to the inner rotor  88  and the outer rotor  90  such that the first slip disk assembly  80  inhibits the transmission of rotational force from the drive assembly  18 , specifically rotation of the first flywheel  64 , to the gear shaft  16  through the inner rotor  88  and the outer rotor  90 . Specifically, at a rotational force equal to or greater than the predetermined rotational force, the frictional engagement between the friction surface  84 A and the rotor surface  88 A and the frictional engagement between the friction surface  86 A and the rotor surface  90 A is overcome which inhibits the transmission of the rotation of the first flywheel  64  from being transmitted to the inner rotor  88  and the outer rotor  90 , as the first flywheel  64  rotates with respect to the inner rotor  88  and the outer rotor  90  the gear shaft  16  is inhibited from being rotated. Accordingly, upon exceeding the predetermined rotational force between the first flywheel  64  and the inner rotor  88  and the outer rotor  90 , the first flywheel  64  slips with respect to the inner rotor  88  and the outer rotor  90  such that there is a decrease in an amount of rotational force from the first flywheel  64  that is transmitted to the inner rotor  88  and the outer rotor  90  which decreases the rotational force of the gear shaft  16 . 
     In some embodiments, the predetermined rotational force is set based on at least one of a friction between the friction surface  84 A and the rotor surface  88 A and a friction between the friction surface  86 A and the rotor surface  90 A, a tightening force of the plurality of fasteners  92  that secure the inner rotor  88  to the outer rotor  90 , and a tension of the drive belt  68 . 
     In some embodiments, the first slip disk assembly  80  includes five fasteners  92  which are tightened between a range of 5.16 to 5.9 foot pounds (ft-lb). In some embodiments, the drive belt  68  is tensioned so as to have a deflection of at least 3 centimeters (cm). 
     Referring to  FIGS. 1-3 , the push plate  20  includes a push surface  20 A that faces the edge  14 A of the splitter  14 . The push plate  20  is coupled to a push seat  110  that slidably engages with the top wall  38  and the side edges  38 A of the top wall  38  such that the push plate  20  is slidable with respect to the frame  12  in the direction of arrow A 1  and A 2 . A biasing member  112 , such as a spring, has one end connected to the push seat  110  and an opposite end connected to the frame member  30 . The biasing member  112  biases the push plate  20  and the push seat  110  in the direction of arrow A 2 . 
     The rack  22  is pivotally coupled to the push plate  20  about a pivot axis P. The rack  22  includes a plurality of teeth  22 A configured to engage with the gear teeth  50  of the gear shaft  16 . An actuator assembly  114  is coupled to the rack  22  to pivot the rack  22  about the pivot axis P between a disengaged position and an engaged position. In the disengaged position, the plurality of teeth  22 A of the rack  22  are spaced apart from gear teeth  50  of the gear shaft  16  such that upon rotation of the gear shaft  16 , the rack  22  is not linearly displaced in the direction of arrow A 1 . In the engaged position, the plurality of teeth  22 A of the rack  22  engages with the gear teeth  50  of the gear shaft  16  such that rotation of the gear shaft  16  linearly displaces the rack  22  and the push plate  20  forward in the direction of arrow A 1  towards the edge  14 A of the splitter  14 . 
     In operation, a log (not shown) is placed on the top wall  38  of the frame member  30  between the edge  14 A of the splitter  14  and the push surface  20 A of the push plate  20 . As the rack  22  is in the disengaged position, with the plurality of teeth  22 A spaced apart from the gear teeth  50  of the gear shaft  16 , the rack  22  is not linearly displaced forward in the direction of arrow A 1  towards the edge  14 A of the splitter  14 . The drive assembly  18 , specifically, the motor  60  outputs a rotational force from the output shaft  62  which is transmitted to the first flywheel  64  by the drive belt  68 . The first slip disk assembly  80  and the second slip disk assembly  82  are in the engaged position such that the rotation of the first flywheel  64  is transmitted through the first slip disk assembly  80  to the gear shaft  16  which rotates the second flywheel  66  through the second slip disk assembly  82 . As the first flywheel  64  and the second flywheel  66  rotate with the gear shaft  16 , kinetic energy is stored in the first flywheel  64  and the second flywheel  66  due to the inertia of the first flywheel  64  and the second flywheel  66 . 
     Upon actuation of the actuation assembly  114 , the rack  22  is pivoted about the pivot axis P from the disengaged position to the engaged position. In the engaged position, the engagement of the gear teeth  50  of the gear shaft  16  with the plurality of teeth  22 A of the rack  22  linearly displaces the push plate  20  forward in the direction of arrow A 1  towards the edge  14 A of the splitter  14  utilizing the stored kinetic energy from the rotation of the first flywheel  64  and the second flywheel  66 . The rotation of the gear shaft  16  linearly displaces the rack  22  in the direction of arrow A 1  from a retracted position to an extended position. The rack  22  and the push plate  20  are linearly displaced forward in the direction of arrow A 1  at a predetermined pressure/tonnage and/or force to split the log placed between the edge  14 A of the splitter  14  and the push surface  20 A of the push plate  20 . 
     In the extended position, the rack  22  is linearly displaced forward in the direction of arrow A 1  such that the plurality of teeth  22 A of the rack  22  are no longer engaged with the gear teeth  50  of the gear shaft  16 . Upon reaching the extended position, the actuation assembly  114  pivots the rack  22  about the pivot axis P to the disengaged position and a biasing force of the biasing member  112  biases the rack  22  and the push plate  20  in the direction of arrow A 2  from the extend position to the retracted position. It is appreciated, that during normal operation of linearly displacement of the rack  22  from the retracted position to the extended position, the automatic brake mechanism  24  permits transmission of rotational force from the first flywheel  64  to the gear shaft  16 , specifically, the first slip disk assembly  80  and the second slip disk assembly  82  are maintained in the engaged position. 
     During operation in which the rack  22  is obstructed from linearly displacing from the retracted position into the extended position, for example, the rack  22  is stopped or jammed as a pressure/tonnage and/or force required to move the rack  22  to into the extended position exceeds the predetermined pressure/tonnage and/or force, the predetermined rotational force of the first slip disk assembly  80  and the second slip disk assembly  82  is exceeded such that the first slip disk assembly  80  and the second slip disk assembly  82  move from the engaged position to the disengaged position such that the transmission of rotational force from the first flywheel  64  and the second flywheel  66  to the gear shaft  16  in inhibited. 
     In some embodiments, the predetermined rotational force is set based on the predetermined pressure/tonnage and/or force, which is applied to the push plate  20  to prevent the linear displacement of the push plate  20  and the rack  22  in forward in the direction of arrow A 1 . Upon exceeding the predetermined pressure/tonnage and/or force applied to the push plate  20 , the rotational force between the first flywheel  64  and the gear shaft  16 , specifically the first slip disk assembly  80 , and the rotational force between the second flywheel  66  and gear shaft  16 , specifically the second slip disk assembly  82 , exceeds the predetermined rotational force such that the first slip disk assembly  80  and the second slip disk assembly  82  moves from the engaged position to the disengaged position such that the first slip disk assembly  80  and the second slip disk assembly  82  inhibit the transmission of rotational force from the first flywheel  64  and the second flywheel  66 , respectively, to the gear shaft  16 . 
     When the rack  22 , in the engaged position with the plurality of teeth  22 A are engaged with the gear teeth  50  of the gear shaft  16  such that rotation of the gear shaft  16  linearly displaces the rack  22  forward in the direction of arrow A 1 , is obstructed (i.e. jammed or stopped) from linearly displacing forward in the direction of arrow A 1  such that that the predetermined pressure/tonnage or force is exceeded, the rack  22  is unable to linearly displace forward in the direction of arrow A 1 . As such, a rotation force required to rotate the gear shaft  16  is increased such that the predetermined rotational force between the gear shaft  16  (i.e. inner rotor  88  and outer rotor  90 ) and the first flywheel  64  (i.e. the inner friction plate  84  and the outer friction plate  86 ) is exceeded which moves the first slip disk assembly  80  and the second slip disk assembly  82  from the engaged position to the disengaged position. 
     By inhibiting the transmission of rotational force from the first flywheel  64  and the second flywheel  66  to the gear shaft  16 , the rotation force of the gear shaft  16  is thereby reduced to prevent excess wear and shock damage to the gear teeth  50  and the plurality of teeth  22 A of the rack  22  due to the continued rotation of the gear shaft  16  as the gear teeth  50  are engaged with the plurality of teeth  22 A of the rack  22  which is obstructed from linearly displacing forward in the direction of arrow A 1 . 
     In some embodiments, the predetermined pressure is 42 tonnage, ±1%, ±5%, or ±10%. 
     In some embodiments, the actuation assembly  114  is configured to pivot the rack  22  from the engaged position to the disengaged position upon movement of the first slip disk assembly  80  and the second slip disk assembly  82  moving from the engaged position to the disengaged position to return the rack  22  to the retracted position. Once the rotational force between the first flywheel  64  and the second flywheel  66  and the gear shaft  16  is less than the predetermined rotational force, the first slip disk assembly  80  and the second slip disk assembly  82  move from the disengaged position to the engaged position. 
     It is noted that the terms “substantially” and “about” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. 
     While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.