Abstract:
A forklift apparatus includes a base that moves in a generally horizontal direction. The base carries a mast that includes a lower section and an upper section. The upper section pivots relative to the lower section between a first storage orientation and a second operating orientation. In the second operating orientation, the upper section forms an upward continuation of the lower section. The mast carries a lifting structure that can selectively engage an object. A drive structure moves the lifting structure in a generally vertical direction when the upper section is in the second operating orientation.

Description:
BACKGROUND 
     Although the human hand is a remarkably useful structure for manipulating objects, there are times when manipulating an object by hand may be inappropriate or impossible. For example, an object may be excessively large, small, heavy, or dangerous. In other situations, a law, rule, or regulation may inhibit a human&#39;s ability to manipulate an object certain settings, for example, in a competition between machines. Although some machines can be used to manipulate objects, such machines can be large and unwieldy. 
     SUMMARY 
     In general, one aspect features a machine that includes a first beam coupled by a hinge to a second beam. The machine further includes a carnage operable to translate along an axis defined by the first beam and the second beam when their axes are relatively aligned. The hinge permits the first beam to rotate, relative to the second beam, thereby reducing the extent of the machine along at least a first dimension. 
     In some embodiments, the carriage is coupled to a chain that forms a substantially continuous loop around the first and second beams. 
     In some embodiments, the machine further includes a controller to control the operation of one or more motors that engage with the hinge and the carriage. The controller may allow the first beam to be selectively rotated about the hinge relative to the second beam. The controller may further allow the carriage to be translated along the first and second beams. 
     In some embodiments, the controller may allow for autonomous operation of the machine. In other embodiments, the controller may be coupled to a radio-frequency communications interface and allow for remote operation of the machine by a human. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is best understood from the following detailed description when read with the accompanying figures. The drawings were prepared with Creo Elements from Parametric Technology Corporation. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. Furthermore, all features may not be shown in all drawings for simplicity. 
         FIG. 1  illustrates one embodiment a machine equipped with a forklift apparatus. 
         FIG. 2  illustrates an alternate view of a machine equipped with a forklift apparatus. 
         FIGS. 3 ,  4  and  5  illustrate alternate perspective views of one embodiment of a forklift apparatus. 
         FIG. 6  illustrates a method for automatically moving a carriage into alignment with a target location. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to a machine for manipulating objects. It is understood, however, that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. 
     Referring to  FIG. 1 , illustrated is one embodiment of a machine  100  equipped with a forklift apparatus  102 . The forklift apparatus  102  includes a lower mast  104  and an upper mast  106 . The lower mast  104  has two substantial portions, a car guide  108  and a structural support beam  110 . The car guide  108  is a front-facing, substantially flat plate and is coupled to the support beam  110 , which is a U-shaped beam. Other configurations are also possible. For example, in some embodiments, the structural support beam  110  may be a box beam, I-beam, may comprise multiple beams, or may have any other suitable configuration. Similarly, in other embodiments the car guide  108  may be a pair of equally-spaced rails or any other suitable structure. And in still other embodiments, the car guide  108  may be entirely absent. 
     The car guide  108  and the structural support beam  110  are aluminum, but they may be made from any suitable material. For example, the car guide  108  and the structural support beam  110  may be another metal, including without limitation examples such as steel, iron, titanium, and tin; wood; plastic; or any combination thereof. The car guide  108  may be coupled to the structural support beam  110  using any suitable technique, including for example threaded screws, nuts and bolts, welding, fusing, glue, or nails. In other embodiments, the car guide  108  and the structural support beam  110  may be cast or formed as a single integrated piece. 
     The upper mast  106  similarly includes a car guide  112  and a structural support beam  114 . The design of these upper mast  106  components is preferably the same as their counterparts in the lower mast. 
     The upper mast  106  couples to the lower mast  104  at a hinge  116 . The hinge  116  includes a pin  118  that passes axially through apertures in the structural support beams  110  and  114 . The hinge  116  provides an articulation point between the upper mast  106  and the lower mast  104 , allowing the upper mast  106  to rotate about the pin while the lower mast  104  remains relatively fixed in position. This articulation is further illustrated in the other figures. Affixed to the pin  118  is an articulation gear  117 . A mast drive motor has a mast drive gear that meshes with the articulation gear  117  to cause the upper mast  106  to rotate about the pin  118 . In this way, the upper mast  106  may be raised and lowered. In other embodiments, the upper mast  106  may be raised and lowered in other ways, including for example by one or more pneumatic or hydraulic cylinders, one or more springs, one or more chains or pulleys, one or more permanent or electro-magnets, or any combination thereof. 
     The forklift apparatus  102  further includes a carriage  120  that translates vertically along the car guides  108  and  112 . The carriage  120  includes two carriage guides  122  and  124  that extend behind the car guides  108  and  112  on the opposite side of the carriage  120 . The carriage guides  122  and  124  thus restrict the lateral movement of the carriage  120  and ensure that the carriage slides smoothly and only vertically. The carriage  120  is equipped with an attachment  126 . The attachment  126  includes two lower fixed prongs and an upper spring prong suitable for capturing and securing a horizontally oriented cylindrical object of appropriate size, such as a baton. In other embodiments, the carriage  120  may include other attachments, either in addition to or in place of the attachment  126 . Example attachments include sensors (including for example a magnetometer, microphone, or video or still image camera), traditional forklift forks, a grasping claw or clamp, a platform, a drum carrier, or any other suitable attachment. The attachment  126  may be detachably attached to the carriage  120  via any suitable mechanism, including for example one or more screws, pins, bolts, latches, hooks, or any combination thereof. The carriage  120  may include a plurality of coupling mechanisms or otherwise be equipped with a plurality of attachments  126 . 
     The carriage  120  is driven along the car guides  108  and  112  by a drive chain  128 . The drive chain  128  is a substantially continuous roller chain formed from interlocking links. The carriage  120  is preferably coupled to the drive chain  128  by a screw or bolt, but any other suitable coupling mechanism may also be used. The drive chain  128  situated to slide along the surface of car guides  108  and  112 , although preferably the drive chain  128  minimal contact—or even no contact—with them. At the upper extremus of the upper car guide  112 , the drive chain  128  engages with a sprocket  130  that is rotatably mounted to an axle  132  affixed to the upper structural support beam  114 . In another embodiment, the sprocket  130  may be affixed to the axle  132  which, in turn, is rotatably mounted to the upper structural support beam  114 . The sprocket  130  has teeth sized to match the links of the drive chain  128  and may be a 24-tooth sprocket. The sprocket  130  may rotate freely under the engagement of the drive chain  128  as the drive chain  128  moves the carriage  120  up and down the car guides  108  and  112 . 
     Continuing to describe the path of the drive chain  128 , from the sprocket  130  the drive chain  128  next engages with a tensioning sprocket  134  rotatably mounted on an axle  136  affixed to a tensioning lever  138 . The tensioning sprocket  134  has teeth sized to match the links of the drive chain  128  and may be a 16-tooth sprocket. The tensioning lever  138  is rotatably mounted to the upper structural support beam  114  using a pin hinge  140 . An elastically deformable loop  142  has a first end that exerts a biasing force on the axle  136 , and inducing a torque on the tensioning lever  138  about the pin hinge  140 . The torque on the tensioning lever  138 , in turn, biases the tensioning sprocket  134  toward the drive chain  128  and away from the upper structural support beam  114 . In this way, the tensioning sprocket  134  removes any excess slack in the drive chain  128  by lengthening the distance the drive chain  128  must traverse as it passes over the tensioning sprocket  134 . 
     The elastically deformable loop  142  has a second end coupled to a fixed mounting point  144 . The fixed mounting point  144  is immovably affixed to the upper structural support beam  114 . In other embodiments, the fixed mount point  144  may be a point on the upper structural support beam  114 . The elastically deformable loop  142  may be any suitable material and should be chosen to provide an appropriate level of tension on the drive chain  128 . As one example, the elastically deformable loop  142  may be a rubber band of appropriate size and strength. In other embodiments, the elastically deformable loop  142  may be replaced with any other suitable biasing device, including, for example, a spring, pneumatic cylinder, or hydraulic cylinder. 
     Further in the description of the path of the drive chain  128 , the drive chain  128  next transits to a hinge sprocket  146  that is affixed to an axle  148  on a bracket  150 . The hinge sprocket  146  has teeth sized to match the links of the drive chain  128  and may be a 24-tooth sprocket. The hinge sprocket  146  may be rotatably mounted to the axle  148 , or the axle  148  may be rotatably mounted to the bracket  150 , or potentially both. Thus, the sprocket  146  may rotate freely under the engagement of the drive chain  128  as the drive chain  128  moves the carriage  120  up and down the car guides  108  and  112 . The axle  148  may also be mounted to a second bracket to provide improved support. In other embodiments, the hinge sprocket  146  may be rotatably mounted to the pin  118 . In still other embodiments, the sprocket  146  may be replaced with two sprockets, one each mounted to upper and lower structural supports  144  and  110  near the hinge  116 . 
     Following the hinge sprocket  146 , the path of the drive chain  128  continues to a sprocket  152  at the lower extremus of the lower car guides  108 . The sprocket  152  has teeth sized to match the links of the drive chain  128  and may be a 24-tooth sprocket. The sprocket  152  is affixed to an axle that is further coupled to a gear  154  and chain drive motor  156 . The chain drive motor  156  meshes with the gear  154  to provide motive force to the gear  154 . The gear  154 , which is affixed to the axle, transfers the motive force to the sprocket  152 , causing the sprocket  152  to rotate and thereby move the drive chain  128  in either direction. The chain drive motor  156  is preferably a reversible DC drive motor, but any suitable type of motor may be used. 
     In some embodiments, the gear  154  may be absent, and the chain drive motor  156  may couple directly to the axle. In still other embodiments, the chain drive motor  156  may couple to the sprocket  152  through a gearbox that couples to the sprocket  152  or otherwise transfers rotational power to the sprocket  152 . 
     From the sprocket  152 , the path of the drive chain  128  continues along the surface of the lower car guide  108  and upper car guide  112  to the carriage  120 . Thus, as previously noted, the drive chain  128  is a substantially continuous chain loop that is effective to transfer the rotational force provided by the chain drive motor to an axial force applied to the carriage  120 , thus inducing a vertical translation of the carriage  120  up and down the car guides  108  and  112 . By selectively applying power to the chain drive motor, the vertical position of carriage  120  can be adjusted as desired for any activity. 
     The forklift apparatus  102  is mounted on a base  160  equipped with treads  162 . The treads  162  allow the machine  100  to be driven over a variety of even, semi-even, and uneven surfaces. In other embodiments, the base  160  may alternatively be equipped with any suitable locomotion mechanism, including for example any number of wheels or legs. The base  160  includes one or more suitable motors for driving the treads or other locomotion mechanism. In still other embodiments, the base  160  may be fixed in place. 
     The base  160  further includes a control module  164  for controlling the operation of the forklift apparatus  102  and, optionally, the treads  162  or other locomotion mechanism. The control module  164  produces one or more signals to control the operation of the chain drive motor and the mast drive motor. The control module  164  may also provide control signals for other operations of the machine  100 . The control module  164  may include a programmable processor and a computer-readable memory storing instructions that, when executed by the programmable processor, produce the one or more signals that control the operation of the chain drive motor and the mast drive motor. The computer-readable memory may also be computer-writable. The control module  164  may further include a plurality of input, output, or input/output ports. Thus, the control module  164  may also receive as input signals from one or more sensors located on or in the machine  100 . In one embodiment, the control module  164  includes a LEGO® MINDSTORMS® NXT Intelligent Brick available from the LEGO Group. 
     The control module  164  may further include one or more wired or wireless communications interfaces to allow for remote control and programming of the machine  100 . For example, the control module  164  may include an 802.11b wireless communications adapter. In one embodiment, the control module  164  includes a Samantha Wi-Fi (IEEE 802.11b) module available in the FIRST Tech Challenge program. In other embodiments, the communications adapter may use another protocol or medium, including for example ZigBee, Bluetooth, IEEE 802.11, radio frequency, infrared, microwave, sonic, electrical, optical, or any other communications protocol or medium. 
     Turning now to  FIG. 2 , illustrated is the machine  100  in a different position as compared to  FIG. 1 . In  FIG. 2 , the upper mast  106  has been lowered by rotating about the hinge  116 . When the upper mast  106  is in the lowered position, the drive chain  128  remains suitably taut due to the dynamic tension adjustment provided by the tensioning sprocket  134 , tensioning lever  138 , and elastically deformable loop  142 .  FIG. 2  also illustrates the carriage  120  located on the lower car guide  108 . It is understood, however, that the carriage  120  may remain on the upper car guide  112  when the upper mast  106  is lowered. With the upper mast  106  in the lowered position, the articulation gear  117  protrudes through an aperture in the lower car guide  108 . 
       FIGS. 3 ,  4  and  5  illustrate alternate perspective views of one embodiment of a forklift apparatus. These figures further illustrate the mechanical features of the articulation point between the upper mast  106  and the lower mast  104 . The articulation gear  117  is a generally large toothed wheel where a segment has been removed. The articulation gear  117  may be formed by cutting a segment off of a complete gear, or it may be directly formed in the appropriate shape. In one embodiment, the articulation gear  117  is formed from an 120-tooth gear, that is, there would be  120  teeth on the articulation gear  117  except that there are in fact less because a segment and its corresponding teeth have been removed. 
     The articulation gear  117  meshes with a mast drive gear  302  that is mounted to a mast drive motor  304 . The mast drive gear  302  is a 40-tooth gear, and thus the mast drive gear  302  and the articulation gear  117  provide a 3:1 drive ratio. The mast drive motor  304  may be a reversible, 12-volt DC drive motor with a maximum speed of about 152 rpm. At maximum speed, the mast drive motor  304  makes about 2.5 revolutions per second, or one revolution in about 0.4 seconds. Since raising or lowering the upper mast  106  requires making a quarter revolution turn of the articulation gear  117  through the 3:1 drive ratio provided by the mast drive gear  302 , the mast drive motor  304  can theoretically raise or lower the upper mast  106  in approximately (0.25 revolution)×(0.4 seconds/revolution)×(3:1 drive ratio)=0.3 seconds. In practice, the mast drive motor  304  begins from rest and thus does not immediately begin turning at 152 rpm. In addition, the mast drive motor  304  may achieve a maximum speed of less than 152 rpm due to the load imposed on it in raising or lowering the upper mast  106 . However, the inventors have found that in practice, the upper mast  106  may be readily raised or lowered in less than about 1 second. 
     In other embodiments, any suitable type of motor may be used, and the mast drive motor  304  may engage the articulation gear  117  through a gearbox. Thus, the speed of raising or lowering the upper mast  106  may be faster or slower as may be desired for any particular application. And in still other embodiments, the mast drive gear  302  and articulation gear  117  may be replaced with suitable sprockets coupled by a chain. 
     The inventors have found that with the 3:1 drive ratio between the articulation gear  117  and mast drive gear  302 , the mast drive motor  304  alone provides sufficient braking force to maintain the upper mast  106  in any position. Thus, once the upper mast  106  is moved to its raised position, there is no need to lock the upper mast  106  in position. Similarly, the upper mast  106  may be stopped and held in any arbitrary position in between its raised and lowered positions. In some embodiments, however, it may be desirable (for safety or other considerations) to provide a mechanical support or brake to held the upper mast  106  in a position. Alternatively, the mast drive motor  302  may be energized to provide a suitable force to counteract other forces, such as gravity, that may induce an undesirable movement of the upper mast  106 . 
     The forklift apparatus  102  may be equipped with one or more sensors, each of which may be of a similar or dissimilar type. For example, the forklift apparatus  102  may include a camera, microphone, or both. As another example, the upper mast  106  may be equipped with a location sensor, which may operate to provide a signal indicative of the forklift apparatus  102 &#39;s position using either relative or absolute positioning. In one embodiment, the location sensor may be a directional infrared sensor that detects the receipt of infrared energy transmitted by one or more fixed waypoints. In another embodiment, the location sensor may be a GPS, GLONASS, or other suitable location sensor. The location sensor may provide one or more signals indicative of position to the control module  164 . 
     Various components of the machine  100 , including for example at least some of the sprockets, the drive chain  128 , and the drive motors, may be obtained from the LEGO GROUP as part of their TETRIX line of robotic components. 
     Software 
     As previously discussed, the machine  100  is equipped with a control module for controlling its operation. The control module preferably includes a programmable processor and a computer-readable memory storing instructions executable by the processor. 
     The control module may include an input allowing instructions for controlling the machine  100  to be received from a remote location. The input may be via any suitable input interface, including for example a Universal Serial Bus (USB), Bluetooth, or IEEE 802.11 interface. In this manner, the machine  100  may be remotely controlled through a wired or wireless connection. When instructions are received through the interface, a threshold filter may be applied to prevent initiating movement in response to a noise produced by the source of the instructions. For example, if the absolute value of the requested movement speed is less than a selected value, such as 10, then the requested movement may be discarded as unintentional noise. As another example, the control module may ignore a request to move the carriage  120  when the upper mast  106  is in the lowered position or is otherwise not in the raised position. 
     The control module may include instructions allowing the machine  100  to operate autonomously. For example, the instructions may include instructions for moving the carriage  120  in response to data provided by a sensor mounted on the carriage  120 . As one example,  FIG. 6  illustrates a method  600  for automatically moving the carriage  120 , when equipped with a magnetometer, into alignment with a target location identified by a magnetic field. As previously discussed, the carriage  120  may be equipped with one or more magnetometers to provide data indicative of the magnetic field near the carriage  120 . 
     The method  600  begins in step  602 . At step  604 , the carriage is initialized by moving the carriage to a known location, for example, to the top or bottom of the forklift apparatus. In some embodiments, the step  604  may be omitted. Next in step  606 , the magnetometer sensors are initialized by clearing out any previously read values and preparing the sensors to take new readings. Then in step  608 , a measured value is read from the magnetometer sensors. If the carriage  120  is equipped with multiple sensors, each sensor reading may be read sequentially. The measured values from the sensors may be stored in a array. 
     Continuing to step  610 , the data obtained from the magnetometer sensors is analyzed to determine whether one or more of the measured values indicates the presence of a magnetic field. In one embodiment, each measured value is compared to a threshold value, which may be predetermined. The threshold value may be selected to correspond to a magnetic field of a particular strength, for example, the strength of a magnetic field within about 2 to 3 inches from a given type of magnet. In other embodiments, other forms of data analysis may be performed. 
     Then in step  612 , it is determined whether the data analysis performed in step  610  indicates that a magnet has been found. If no magnet has been found, then the process proceeds to step  614 , where the carriage is moved. The carriage may be moved in a uniform direction a predetermined distance or for a predetermined amount of time, although other possibilities are also contemplated. The carriage may be moved, for example, by activating the carriage drive motor to turn a sprocket engaged with the drive chain. After the carriage has been moved, the process returns to step  608 . In some embodiments, the steps  608  to  614  may occur simultaneously, such that data from the magnetometer sensors is substantially continuously analyzed as the carriage moves in a uniform direction. 
     If in step  612  it is determined that a magnet has been detected, then the process proceeds to step  616 , where the process ends. In this way, the carriage may be automatically aligned with a target location identified by a magnet producing a magnetic field. In other embodiments, other types of sensors may be used, including for example, sensors providing indications of light, sound, distance, or temperature. The method  600  may be readily used with these other types of sensors to similarly automatically align the carriage with a target location identified by measurements taken from such sensors. 
     The present disclosure has been described relative to a preferred embodiment. Improvements or modifications that become apparent to persons of ordinary skill in the art only after reading this disclosure are deemed within the spirit and scope of the application. For example, the forklift apparatus has been described as having a generally vertical orientation, but it is understood that the forklift apparatus may alternatively be mounted in a horizontal, inverted, or any other orientation. 
     It is understood that several modifications, changes and substitutions are intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.