Patent Publication Number: US-2007095612-A1

Title: Child safety stool

Description:
FIELD OF THE INVENTION  
      The present invention relates to a stool for aiding access to raised structure such as a cabinet or vanity.  
     BACKGROUND OF THE INVENTION  
      Interacting with elements of the adult world is often difficult for children given their small size. For instance, access to structures such as cabinets, tabletops, vanities, etc. is difficult given the relative height of their top surface as compared to a child. As such, children may become reluctant to engage in educational or personal hygiene activities (e.g., teeth brushing) when the use of such structures is required.  
      Conventionally, various step stools have been used to allow children and shorter people access to the top surface of such structures. However, many conventional stools are prone to tipping, which may cause injury to the user. Some step stools include designs for attaching the stool to certain cabinets so as to help prevent tipping. However, these stools are generally unacceptable as they are designed for only one specific type of cabinet, and the attachment to such cabinets is semi-permanent and cumbersome to remove. Often, the attachment of such stools to a cabinet or vanity renders the lower cabinet shelving space unusable.  
     SUMMARY OF THE INVENTION  
      In view of the foregoing, the present invention provides a child safety stool designed to selectively engage with a vanity, cabinet, or other structure of varying heights so as to provide a low-profile, tip-resistant stool. The stool will allow users, typically children, to reach a sink, e.g., and encourage them to perform personal hygiene. By engaging with the lower lip of a raised base portion that exists on a majority of cabinets and vanities, the stool is prevented from tipping outward. Because the stool is making contact with the vanity on the back portion, it is unable to tip in that direction, thus producing a stable, low-profile standing platform for use by children to access a sink of counter for hygiene or education purposes.  
      The stool utilizes selectively movable engaging elements to “lock” the stool in place to a structure. The stool utilizes a mechanically activated locking mechanism to raise the engaging elements into a locked position. For example, one embodiment of the invention utilizes a rotary plate on the front of stool, along with a pulley and bearing assembly, to convert the rotary motion of the plate to linear motion of rigid arms that engage with the structure. A lock release mechanism lowers the engaging elements from the cabinet and allows the stool to be moved. The quick engagement and detachment allows the stool to be quickly and easily moved for allowing access to cabinets that may be located in the engagement area.  
      As such, the invention provides a tip-resistant stool for aiding access to an elevated surface of a structure having a raised base portion. The stool includes a main body, one or more engaging elements, and a locking mechanism. The main body has at least top surface and a front surface, the top surface being a step surface. The one or more engaging elements extend rearwardly from the main body. The locking mechanism is in mechanical connection with the one or more engaging elements and is for selectively locking the one or more engaging elements in an engagement position with the raised base portion of the structure, whereby the stool is prevented from tipping when the one or more engaging elements are in the engagement position.  
      The stool may also include a selectively accessible intermediate step that is made accessible when the one or more engaging elements are in the engagement position. The intermediate step comprises a recess in the front surface of the main body including an intermediate step surface disposed within the interior of the main body, wherein the intermediate step has a predetermined size to accommodate a user&#39;s foot. The stool may further include a selectively movable blocking member cooperating with the one or more engaging elements such that the blocking member restricts access to the intermediate step when the one or more engaging elements are not in the engagement position.  
      The locking mechanism may include an artistic design, wherein the artistic design becomes properly aligned when the one or more engaging elements is in the engagement position. In this way, children are encouraged to use the locking mechanism to lock the stool into place.  
      It is to be understood that the descriptions of this invention herein are exemplary and explanatory only and are not restrictive of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1A  depicts a child safety stool according to one embodiment of the invention in a typical operating environment.  
       FIG. 1B  depicts a child safety stool according to one embodiment of the invention in an engaged position.  
       FIG. 2  depicts a front view of a child safety stool according to one embodiment of the invention.  
       FIG. 3  depicts a side view of a child safety stool according to one embodiment of the invention.  
       FIG. 4  depicts a back view of a child safety stool according to one embodiment of the invention.  
       FIG. 5  depicts a locking arm assembly of a child safety stool according to one embodiment of the invention.  
       FIG. 6  depicts a locking arm adjuster of a child safety stool according to one embodiment of the invention.  
       FIG. 7  depicts a back view of a pulley and bearing assembly of a child safety stool according to one embodiment of the invention.  
       FIG. 8  depicts a back view of a pulley assembly and lock mechanism of a child safety stool according to one embodiment of the invention.  
       FIG. 9  depicts a lock mechanism of a child safety stool according to one embodiment of the invention.  
       FIG. 10A  depicts the rotary front plate in the unlocked position according to one embodiment of the invention.  
       FIG. 10B  depicts the rotary front plate in the locked position according to one embodiment of the invention.  
       FIG. 11  depicts a pull-out step locking mechanism according to one embodiment of the invention.  
       FIG. 12  depicts a slide-down step locking mechanism according to one embodiment of the invention.  
       FIG. 13  depicts a side actuator locking mechanism according to one embodiment of the invention.  
       FIG. 14  depicts an L-shaped pivot locking arm according to one embodiment of the invention.  
       FIG. 15  depicts a rotating locking arm according to one embodiment of the invention.  
       FIG. 16  depicts a sliding locking arm according to one embodiment of the invention.  
       FIG. 17  depicts a cam-actuated locking arm according to one embodiment of the invention.  
       FIG. 18  depicts a ratcheting locking arm according to one embodiment of the invention.  
       FIG. 19  depicts an end view of the ratcheting locking arm.  
       FIG. 20  depicts a top view of the ratcheting locking arm.  
       FIG. 21  depicts a release mechanism for the ratcheting locking arm.  
       FIG. 22  depicts a weight-activated locking arm according to one embodiment of the invention. 
    
    
     DESCRIPTION OF THE EMBODIMENTS  
      Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings.  
       FIG. 1A  shows a child safety stool according to one embodiment of the invention in a typical operating environment. Safety stool  100  including main body  102 , rotary front plate  104  and locking arm(s)  112  is positioned next to structure  50 . Structure  50  is a cabinet, vanity of any other structure with a raised base portion. As shown here, structure  50  has a raised base portion  55 . In operation, safety stool  100  is placed next to structure  50  so that its engaging elements (i.e., locking arms  112 ) are positioned under raised base portion  55 . A locking mechanism is then mechanically activated so that the engaging elements are moved into an “engagement position.” This engagement position occurs when locking arms(s)  112  are raised so that they make contact with raised base portion  55 . In this way, stool  100  is locked to structure  50  and the stool is prevented from tipping backward.  FIG. 1B  shows the safety stool in the engagement position.  
      In  FIG. 1A , the locking mechanism is shown as a rotary front plate  104  that converts rotational movement of the plate to linear motion (in this case vertical motion) of the locking arms. Once the rotary front plate moves the locking arms into the engagement position, the front plate locks and the arms are held in place. The locking arms are released from the locking position by locking arm release knob  110 . The features and operation of safety stool  100  will be discussed in more detail below with reference to FIGS.  2  to  10 .  
       FIG. 2  shows a front view safety stool  100 . As seen from the front, main body  102  includes a rotary front plate  104 , an intermediate step access hole  106 , an intermediate step  108 , and a locking arm release knob  110 . Main body  102  houses all components of the stool and acts as the structural support of the stool. Preferably, main body  102  is made of wood or plastic, however any material that is able to support the weight of a user is suitable. Top surface  103  of main body  102  serves as the primary step. Top surface  103  is preferably covered in a non-skid material to prevent the primary step from becoming slippery if wet, however any surface finish is suitable. In addition, the rear surface of safety stool  100  may be covered in a non-marring material such that contact with a cabinet or structure would not damage the cabinet or structure. Furthermore, a non-skid material may be applied to the tops locking arms  112  and/or the bottom surface safety stool  100  to prevent it from sliding away from the cabinet while in the engaged position.  
      Preferably, main body  102  is box-shaped and has a substantially flat top surface  103 , however any shape capable of bearing the weight of a user may be used. Preferably, main body is 12 to 16 inches high, 16 to 20 inches wide, and 5 to 7 inches deep. However, any size of stool may be suitable. For example, taller or shorter stools may be desirable for use with cabinets or structures of different heights. In addition, deeper or narrower stools may be advantageous depending on the amount of overhang on the upper surface of a structure. For example, a structure with a deep upper overhang may be more suitable for a deep stool so that the user may stand far enough back to gain access to the upper surface of the structure. In addition, wider or narrower stools may be advantageous in certain situations. For example, a wider stool may be desirable so that two or more users may use the stool at once.  
      Rotary front plate  104  serves as the primary lever for raising locking arms  112 . Rotary front plate  104  contains intermediate step access hole  106  such that when rotary front plate  104  is turned into the locking position (i.e., counter-clockwise), access is granted to intermediate step  108 . Rotary front plate  104  could also be made to turn clockwise to engage the locking position. Rotary front plate  104  is preferably 11 to 12 inches in diameter and approximately centered in both the vertical and horizontal planes of the front of main body  102 . However, any size, shape or position of rotary front plate may be used.  
       FIGS. 10A and 10B  show rotary front plate  104  in the unlocked and locked positions, respectively. In one embodiment, rotary front plate  104  bears an artistic design  105  so as to encourage proper use by children. Artistic design  105  is setup in such a manner that it is completed or properly aligned when rotary front plate  104  is in the locked position.  
      Referring back to  FIG. 2 , intermediate step access hole  106  is an opening in rotary front plate  104  that provides a gripping surface for turning rotary front plate  104 . Intermediate step access hole  106  is positioned such that intermediate step  108  is only accessible when rotary front plate  104  is in the locked position. When rotary front plate  104  is not in the locked position, intermediate step  108  is blocked by rotary front plate  104  and intermediate step access hole  106  is backed by a solid piece to prevent use. Intermediate step  108  serves as a stepping aid to allow easier access to the primary step on top surface  103 .  
      Locking arm release knob  110  activates a mechanism to unlock the stool when pulled mechanically. This allows the stool to be detached from the engaging point of a structure. The actual size of release knob  110  is not limited, but may be any size that is reasonable for a small child to operate. For example, the release knob may be approximately 0.75 to 1 inch in diameter. Preferably, the release knob is located approximately one inch from the rear surface of main body  102  and approximately six to seven inches from the bottom. However, the exact final position may be located in any place, so long as the release mechanism is operable vis a vis the internal mechanical components. The locking and release mechanism will be discussed in more detail below with respect to  FIGS. 8 and 9 .  
       FIG. 3  shows a side view of safety stool  100 . As can be seen from the side, main body  102  includes a locking arm  112  that extends rearwardly from the main body. Locking arm  112  is a moveable arm that will rise to make contact with the lower lip of a cabinet (structure  50 ), vanity or other right overhang to allow the stool to be locked in place to prevent inadvertent tippling. These arms are mechanically linked to rotary front plate  104  such that when rotary front plate  104  is rotated, locking arm  112  moves vertically. In position A, locking arm  112  is in an unlocked position. In position B, locking arm  112  is in a locked position. Locking arm  112  is preferably rigid and made of wood or plastic, however, any material suitable for engaging with a structure may be used. Preferably, locking arm  112  is seven to eight inches long, with three inches protruding from the rear of main body  102 , and is rectangular-shaped when looked at on end (approx. 1.25 to 1.5 inches high and 0.75 inches wide). However, longer or shorter locking arms may be used to effect engagement with different structures.  
       FIG. 4  shows a back view of safety stool  100 . As can be seen from the back, there are two locking arms  112  that are positioned within locking arm slots  114 . More or fewer locking arms could be used. Locking arm slots  114  are holes in the rear cover panel of the stool that allow movement of locking arms  112  such that they can move vertically to engage with the engaging point. Preferably, locking arms  112  experience 0.75 to 3 inches of when moved from the unlocked to the locked position. As such, locking arms slots  114  are preferably 4.5 to 5 inches high. However, the stool may be designed for greater or lesser locking arm travel for use with cabinets and structures of varying sizes.  
      Pulley and bearing assembly  116  is represented with dashed lines as it is contained within the interior of main body  102 . Pulley and bearing assembly  116  supports and contains the pulleys and bearings used to convert rotary motion of rotary front plate  104  into linear motion of locking arms  112 . Pulley and bearing assembly  116  also serves as the support member for lock mechanism  318  which will be discussed in more detail with reference to  FIGS. 8 and 9 . Pulley and bearing assembly  116  will be discussed in more detail with reference to  FIGS. 7 and 8 .  
       FIG. 5  shows a detailed view of the locking arm assembly. Locking arm retraction cable  202  mechanically connects locking arms  112  to pulley and bearing assembly  116  such that, when rotary front plate  104  is rotated into the locking (engagement) position, locking arms  112  are lifted to make contact with the engaging point. Locking arm retraction cable pin  204  mechanically connects locking arm retraction cable  202  to locking arms  112 .  
      Locking arm return spring  206  forces locking arms  112  to full down position (i.e., unlocked position) when rotary front plate  104  is other than in the locked position. This allows the stool to be more easily displaced from the cabinet or other engagement point. Spring control rod  208  forces locking arm return spring  206  to be aligned in a predetermined position to ensure maximum designed spring response such that the spring is allowed to work properly on locking arms  112 . As locking arms  112  are raised, spring control rod  208  slides up through the center of locking arms return spring  206  and through a hole in support member  214 .  
      Spring retention plate  210  contacts support member  214  and locking arm return spring  206  to prevent the locking arm return spring from transiting through the hole designed for spring control rod  208 . This allows for spring control rod  208  to travel through the center of spring retention plate  210  without interfering with its free travel. Control rod pin  212  mechanically links spring control rod  208  to locking arms  112 .  
      Support member  214  connects to main body  102  of the stool to provide extra support from the frame as well as to be a contact point for locking arm return spring  206 . Pivot pin support block  216  is located on the inner side of each locking arm  112 . Pivot pin support block  216  contains a hole into which pivot pin  218  is allowed to rotate. Pivot pin  218  then transits through locking arm  112  and into a hole in main body  102 . This provides for the locking arm to be allowed to pivot freely and be attached in a secure manner to the frame. Pivot pin  218  passes from the frame of main body  102 , through locking arms  112 , and into pivot pin support block  216 . This allows for a secure pivot point for the locking arms, allowing them to move freely in the vertical.  
      Adjuster access hole  220  is a small hole through locking arms  112  that allows for the adjuster block retention screw  222  (see  FIG. 6 ) to penetrate the locking arms in order that it may link with and lock into place with adjuster block  224  ( FIG. 6 ). In this way, the locking arms may engage with varying heights of the lower rigid portion of the engagement surface of a structure.  
       FIG. 6  shows the locking arm adjuster in more detail. Adjuster block retention screw  222  is a screw with which to attach adjuster blocks  224  to locking arms  112 . Preferably, the end of the screw has male threads to engage with matching female threads internal to the adjuster blocks. However, any type of connector is suitable. The other end of retention screw  222  is a knob designed for easy grip to allow the retention screw to be hand tightened into the adjuster blocks. Adjuster blocks  224  are blocks of varying size, preferably with internal female threads and protruding bumps such that the bumps are designed to engage with divots (not shown) in locking arms  112  to increase the security of the engagement. By attaching adjuster blocks  224 , the locking arms are allowed to engage with the lower rigid portion of the engagement surface of varying heights. Spacer washer  226  is a small washer that is optionally used to reduce the amount of penetration adjuster block retention screws  222  when thin adjuster blocks are used.  
       FIG. 7  shows pulley and bearing assembly  116  in more detail. Bearing and pulley support member  302  is the primary support and load bearing member that keeps pulley assembly  310  securely in place while allowing it to freely rotate so as to allow for the conversion of rotary force imparted by rotary front plate  104  to linear motion for locking arms  112 . Bearing and pulley support member  302  also acts as the housing for the bearing on which the pulley assembly is allowed to rotate.  
      Rotary shaft  304  connects pulley assembly bearings  308  and pulley assembly  310  which is attached to rotary front plate  104  together. Rotary shaft  304  is secured to the frame via pulley assembly bearings  308  and retaining nut  306 . Spacer inserts may be used to prevent the pinching of the pulley assembly bearing casing when retaining nut  306  is tightened. Retaining nut  306  screws onto rotary shaft keeping all components securely fastened to pulley support member  302 .  
      Pulley assembly bearings  308  are used for smooth and low friction rotary motion of rotary front plate  104  and attached pulley assembly  310 . Pulley assembly bearings reduce the amount of force required to overcome rotational friction allowing for easier operation of the device. Preferably they are ball bearings, however any type of bearing may be used.  
      Pulley assembly  310  includes drive pulley  311  and the attached bearings and hardware that are mechanically and positively attached to rotary front plate  104 . Drive pulley  311  is mechanically attached to locking arm cable  312 . Drive pulley  311  is designed to collect locking arm cable  312  as rotary front plate  104  is rotated into the locked position. By being mechanically attached to the locking arm retraction cable  202 , drive pulley  311  converts the rotary motion of rotary front plate  104  and attached pulley assembly  310  to linear motion of locking arms  112 . Pulley assembly  310  also contains ratchet mechanism  324  (see  FIG. 8 ) that interacts with friction plate  326  (see  FIG. 8 ) such that rotary motion is not restricted when rotary front plate  104  is rotated in the direction to engage locking arms  112 . However, additional friction is applied when rotary front plate  104  is rotated in the direction to disengage the locking arms such that the rotary front plate is not allowed to “snap” back to the unlocked or disengaged position.  
      Locking arm cable return spring  313  applies spring pressure to help fully retract locking arm retraction cable  202  when the stool is unlocked. Cable routing pulleys  314  are pulleys used to route and properly align, with minimal frictional losses, locking arm retraction cables  202  from locking arms  112  to attachment point on drive pulley  311 .  
      Intermediate step housing  316  is an enclosed step and associated supports to provide an internal step that allows for an intermediate step, while preventing an inserted foot from becoming entangled with the inner workings of the stool. Access to intermediate step housing is provided by intermediate step access hole  108  when rotary front plate  104  is in the locked position (see  FIG. 2 ).  
      Lock mechanism  318  is an assembly that locks drive pulley  311  and attached rotary front plate  104  and locking arms  112  in place to provide positive engagement with the lower edge of an engagement point of a structure. Lock release cable  320  is a cable attaching release knob  110  to release pivot  336  to transfer force applied to release knob  110  to be transferred to release pivot  336  to unlock and lower locking arms  112 .  
      Pulley position locking notch  322  is a notch in drive pulley  311  into which locking pin  328  is inserted when rotary front plate  104  is rotated into a locked or engaged position. When locking pin  328  is inserted in pulley position locking notch  322 , drive pulley  311  and attached components are mechanically locked in place. This forces locking arms  112  to make positive and rigid contact with lower edge of the overhang of a structure (i.e., the engagement point) such that the stool is prevented from tipping.  
       FIGS. 8 and 9  show the pulley assembly and lock mechanism in more detail. Ratchet mechanism  324  includes tabs on the edge of drive pulley  311  that interact with friction plate  326  such that rotary motion is not restricted when rotary front plate  104  is rotated in the direction to engage locking arms  112 , however, additional friction is applied when rotary front plate  104  is rotated in the direction to disengaged the locking arms such that the rotary front plate is not allowed to “snap” back to the unlocked or disengaged position. It is desired to reduce the rate at which the stool unlocks to prevent injury in the case of inadvertent failure to fully lock the stool or if care is not taken during the unlock process.  
      Friction block  325  is a block designed to make contact with and rub on the outer edge of friction plate  326  creating a small amount of resistance to the friction plate rotating so as to reduce the rate of unlocking or disengaging. Friction block  325  is held against friction plate  326  by friction block springs  327 . Friction plate  326  is a disc with detents that interact with the ratchet mechanism tabs on drive pulley  311  such that the drive pulley rotation has resistance only applied when rotary front plate  104  is rotated in the unlocking position. Friction block springs  327  are springs which hold pressure on the friction blocks to increase the rotational friction applied to drive pulley  311  when rotated in the unlocking direction. Friction block springs  327  are attached to the bearing and pulley support member to apply force on, and keep in place the friction blocks.  
      Locking pin  328  is a spring actuated pin designed to interconnect with pulley position locking notch  322  to mechanically lock locking arms  112  in an engaged position. Locking pin  328  is held firmly in alignment and allowed to move in only one axis by retainer housing for lock assembly  338  and spring actuated by lock mechanism spring  330 . Lock mechanism spring  330  is a spring designed to apply positive pressure on the locking pin such that when rotary front plate  104  is rotated into the locked (engaged) position, the locking pin and the pulley position locking notch are aligned and the locking pin is forced into the pulley position locking notch. Locking pin  328  is disengaged from pulley position locking notch  322  by activation of locking arm release knob  110  via lock release cable  320  and release pivot  336 . The disengagement of locking pin  328  allows pulley assembly  310  and all attached components to be rotated to the unlocked position by locking arm cable return spring  313 . When locking pin  328  and pulley position locking notch  322  are not engaged, the locking pin will slide on the outer edge of drive pulley  311 .  
      Lock mechanism spring retainer  332  is a ring that is physically and mechanically attached to locking pin  328  such that the force from lock mechanism spring  330  is applied to the locking pin. Lock release lift plate  334  is a circular plate physically attached to the top of locking pin  328  such that the motion of release pivot  336  can be applied to the locking pin, thus disengaging the locking pin from pulley position locking notch  322 . Release pivot  336  is an L-shaped pivoting bracket designed to redirect linear force applied to lock release cable  320  from locking arm release knob  110  to disengage locking pin  328  on command. Release pivot stop block  342  prevents release pivot  336  from over-rotating, thus preventing the pivot from disengaging with lock release lift plate  334 .  
      Retainer housing for lock assembly  338  securely holds locking pin  328 , forcing it to remain aligned at a specified axis from pulley position locking notch  322 . Along that axis, locking pin  328  is allowed to move in such a manner as to be able to move predictably to engage with and disengage from pulley position locking notch  322 . The retainer housing also serves as the rigid point from which lock mechanism spring  330  applies pressure to locking pin  328 . Release knob return spring  340  is a spring designed to provide pressure on locking arm release knob  110  such that the locking arm release knob is returned to the stowed position when not physically being operated by the stool operator.  
      The child safety stool of the invention is not limited to the embodiment described above with reference to FIGS.  1  to  10 . In fact, any engagement element (e.g., locking arms  112 ) and locking mechanism (e.g., rotary front plate  104  in conjunction with pulley and bearing assembly  116 ) that facilitates selective engagement with a structure may be employed. FIGS.  11  to  22  present some additional examples of engagement elements and locking mechanisms.  
       FIG. 11  depicts a pull-out step locking mechanism. Pull-out locking mechanism  1100  includes a pull-down step  1106  that is mounted to main body  1102  of a stool by pivot pin  1108 . Pull-down step  1106  rotates about pivot pin  1108  and acts as an actuating lever for any engagement elements, such as a locking arm. The mechanical function of raising the locking arm may be accomplished by direct linkage or through cables. The mechanical linkage or cable could be attached to either triangular support step  1110  or to an additional lever that could be extended from the pull-down step. Triangular step support  1110  also functions as an intermediate step in conjunction with intermediate step cutout  1104 .  
       FIG. 12  depicts a slide-down step locking mechanism. The front panel of main body  1212  includes intermediate step cutout  1214  which is covered by sliding step cover  1216 . Access to the intermediate step cutout is gained by sliding down sliding step cover  1216 . In addition, the act of sliding down the step cover also actuates the engaging elements, such as locking arms  112 , to engage with a structure. The mechanical motion of the engaging elements is activated by restraint/actuation point  1218 . Restraint/actuation point  1218  is a tab that is attached to a cable to cause the linear motion to move the locking arms. In addition, restraint/actuation point  1218  holds sliding step cover  1216  in position such that the sliding step cover moves in a vertical direction. This slide-down step locking mechanism would be used in place of the rotary front plate and pulley mechanism described above.  
       FIG. 13  depicts a side actuator locking mechanism. In this embodiment, main body  1320  includes a permanently accessible intermediate step  1322 . Engaging elements are locked into place by pulling down actuating lever  1324 . Actuating lever  1324  is a lever arm that is attached to a cable or other linkage method that, when moved, would mechanically move the locking arms. This method would be hand operated and internal locking linkage would work essentially the same as previous other methods.  
       FIG. 14  depicts an L-shaped pivot locking arm. Rather than a rigid, straight locking arm that is as shown in FIGS.  1  to  10 ,  FIG. 14  shows an L-shaped pivoting locking arm  1404  that pivots on pivot pin  1406 . One end of pivoting locking arm is mechanically pulled down to so that the L-shaped end moves up into an engagement position. Pivoting locking arm  1404  is housed within a sliding adjuster section  1408  in main body  1402 . This allows the locking arm to be slid up and down so as to accommodate structures of varying heights. Sliding adjuster section  1408  may be constructed a sliding housing for the locking arm and the locking arm could be L shaped as shown. This would provide another way to adjust to structures of varying heights.  
       FIG. 15  depicts a rotating locking arm. Main body  1510  includes a rotary locking engaging arm  1512  on its back surface. Rotary locking engaging arm  1512  is rotated about shaft  1512  into an engagement position. Rotary locking engaging arm  1512  may be raised into the engagement position using any mechanical means, including the rotary front plate and pulley and bearing assembly described with reference to FIGS.  1  to  10 .  
       FIG. 16  depicts a sliding locking arm. Main body  1616  includes a sliding locking arm  1618 . Sliding locking arm  1618  is connected to a backing plate  1622  on the inside of the main body via connecting rod  1620 . Mechanical force is applied to backing plate  1622  to move sliding locking arm  1618  into an engagement position. The internal operation of this embodiment would be the same as that described above with reference to  FIGS. 8 and 9 . However, rather than raising, the locking arm of this embodiment slides. An engagement cable would pull on the upper portion of backing plate  1622  forcing sliding locking arm  1618  to engage with the lower lip of the kick plate of a cabinet. Connecting rod  1620  attaches backing plate  1622  and sliding locking arm  1618  together such that they cooperate to counteract torque put on the sliding locking arm from engagement and to force the sliding locking arm and the backing plate to slide along a specified track together.  
       FIG. 17  depicts a cam-actuated locking arm. Main body  1724  includes a locking arm  1726  extending rearwardly from the back surface. Locking arm  1726  is positioned in locking arm slot  1730 . Locking arm slot  1726  rotates about locking arm pin  1728 . Locking arm  1726  is raised by the rotation of cam  1732 . As the larger diameter lob of the cam is rotated to point up, locking arm  1726  raises into the engagement position. In this embodiment, locking arms  1726  are mechanically raised in a similar fashion as locking arms  112  (as described above with reference to FIGS.  1  to  10 ). Rotary force of a rotary front plate (via cables, chains or rotating gears) is transferred to cams  1732 . As the cams are rotated, locking arms  1726  are lifted into place.  
       FIG. 18  depicts a ratcheting locking arm. The locking arm structure includes ratcheting locking arm  1812 , engaging wire and spring  1814 , support frame  1816 , retraction spring and guide bar  1818 , locking ratchet mechanism  1820 , and ratchet unlock cable  1822 . Locking ratchet mechanism  1820  is preferably contained, at least partially, in the interior of ratcheting locking arm  1812 . However, it is also acceptable to mount the locking ratchet mechanism to the outside of the locking arm, such as on the top of the locking arm. Likewise, ratchet unlock cable  1822  is preferably contained within the interior of the locking arm, but may also be mounted on the outside.  
      In this embodiment, by raising engaging wire and spring  1814 , the locking ratchet mechanism  1820  engages with ratchet engagement teeth  1824  (see  FIG. 19 ) to raise locking arm  1812  into an engagement position with cabinets of varying heights. The spring tension lifts locking arm  1812  to touch the bottom of the engagement surface. The engaging wire and spring may be raised by any mechanism, and is preferably raised utilizing the rotary front plate and pulley and bearing assembly described above with reference to FIGS.  1  to  11 . In this embodiment, the ratchet mechanism provides the force to the locking arms in place, rather than the locking pin as described in the first embodiment. As such, less stress is exerted on the mechanical assembly used to raise the locking arm when the locking arm is in the engagement position.  
      As in the first embodiment, the locking arm is lowered from the engagement position by retraction spring and guide bar  1818  when ratchet unlock cable  1822  is pulled. The operation of ratchet unlock cable  1822  will be described in more detail with reference to  FIGS. 20 and 21 .  
       FIG. 19  shows an end view of ratcheting locking arm  1812  and locking ratchet mechanism  1820 . As the locking arm is raised, locking ratchet mechanism  1820  slides over and locks into ratchet engagement teeth  1824  which are contained within a channel in the main body of the stool. As previously indicated, most components of locking ratchet mechanism are internal to the locking arm, and as shown, only the locking elements of the locking ratchet mechanism protrude from the locking arm. However, the locking ratchet mechanism may be mounted outside the locking arm, such as on top of the locking arm.  
       FIG. 20  shows the top view of the ratcheting locking arm and locking ratchet mechanism. Locking ratchet mechanism  1820  includes locking elements  1834 , engagement members  1832 , spring chamber  1830 , and ratchet spring  1828 . Point A of locking ratchet mechanism  1820  is fixed, while Point B is movable. In operation, when there is tension on release cable  1822 , Point B of the locking ratchet mechanism is pulled in and engagement members  1832  compress ratchet spring  1828 . This causes locking elements  1834  to be pulled away from ratchet engagement teeth  1824  ( FIG. 9 ) and the locking arm lowers to an unengaged position.  
      When engaging wire and spring  1814  is raised, such as through the rotation of a rotary front plate and a connected pulley and bearing assembly as described above, the locking arm is raised and locking elements  1834  are pulled over ratchet engagement teeth  1824 . When the locking arm hits an overhang of a structure (i.e. the engagement point), movement of the locking arm is stopped and the locking elements into the ratchet engagement teeth. In cases where the stool has more than one locking arm (two is preferable), each locking arm may raise independently of the other, and as such, the locking arms may raise to different heights to engage an uneven surface or surface with varying overhang heights.  
      As described in the paragraph above, as the locking arms are raised, locking elements  1834  “ratchet” and lock over each subsequent ratchet engagement tooth. However, such continual ratcheting is not required. It may be preferable to have the locking elements only “lock” when the mechanism for raising the arms (e.g., the rotary front plate and bearing and pulley assembly) is locked. This would avoid situations where the locking arms become “stuck” in a halfway position when the rotary front plate is not fully rotated to the locked position.  
       FIG. 21  shows a mechanism in combination with ratchet unlock cable  1822  that prevents the locking elements from “locking” with the engagement teeth unless the mechanical raising mechanism is also in a locked position. As shown, ratchet unlock cable  1822  is connected to release rocker arm  1860 . Tension on release cables  1840  and  1842  are transferred through release rocker arm  1860  to ratchet unlock cable  1822 . Release cables  1840  and  1842  are in tension so long as locking pin  1850  is not in a locked position. For example, with reference to the description in  FIG. 7  above, locking pin  328  is inserted into pulley position locking notch  322  when rotary front plate  104  is rotated into a locked or engaged position. As such, when using the raising mechanism described with reference to  FIG. 7 , release cables  1840  and  1842  would be tension until the locking pin is inserted into the locking notch (i.e., the rotary front plate is in a locked position).  
      When locking pin  1840  is in the locked position, tension is released from release cables  1840  and  1842 , and as such, tension is released from ratchet unlock cable  1822 . In turn, a release of tension from ratchet unlock cable  1822  causes ratchet spring  1828  to decompress the ratchet mechanism allowing locking elements  1834  to lock with engagement teeth  1824  (see  FIGS. 18 and 19 ).  
       FIG. 22  depicts a safety stool that includes a weight-activated locking arm. The safety stool according to this embodiment includes main body  2200 , locking arm  2202 , step  2204  (optional), and adjustment/engagement device  2206 . Locking arm  2202  is raised into a locking position by applying weight to the stool. The weight applied to the stool causes the adjustment/engagement device to raise the locking arms. Typically, weight is applied to the stool by stepping on it. Preferably, the weight required to activate the locking arm is large enough that only adults may activate the stool, however, any weight threshold for activation may be employed.  
      Adjustment/engagement device  2206  is a dual function device that includes adjustment screw  2208 , adjustment thumb wheel  2210 , engagement piston  2212 , engagement spring  2214 , and contact point  2216 . Adjustment/engagement device  2206  is mounted in main body  2200  such that the lower portion of engagement piston  2212  protrudes below the lower surface of the stool so that when the weight of a user is applied to the stool, engagement spring  2214  compresses forcing contact point  2216  to press on adjustment screw  2208  transferring force to locking arm  2202  and forcing contact with the lower portion of an overhang or kick plate of a cabinet or structure.  
      Adjustment screw  2208 , when twisted, forces locking arm  2202  to a higher resting (unlocked) position such that when activation force is applied, the locking arm reaches a higher engagement height allowing for cabinets of various sizes to be used. Adjustment screw  2208  is adjusted with adjustment thumb wheel  2210  which protrudes through the side of the stool.  
      Engagement piston  2212  receives force from compressed engagement spring  2214  via contact point  2216  such that force is transferred to the adjustment screw and onto the locking arm. Engagement spring  2214  allows for compression such that damage is lessened to the lower lip of a cabinet to which the stool is engaging. An adjuster could be used in conjunction with the engagement spring so as to provide different levels of engagement force for different weights of users. Contact point  2216  provides for a transfer of force from the engagement spring to the adjustment screw and then onto the locking arms.  
      Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and embodiments disclosed herein. Thus, the specification and examples are exemplary only, with the true scope and spirit of the invention set forth in the following claims and legal equivalents thereof.