Abstract:
A lifting device for transporting a component from a first position to a second position is provided. The second position is defined relative to a destination datum feature. The lifting device includes a computing device and an arm having a clamp mechanism and a locator mechanism. The arm is selectively movable to engage the component, removably couple the component to the arm using the clamp mechanism, and facilitate transport of the component to the second position. The locator mechanism includes a datum feature that interacts with the destination datum feature to transmit a signal to the computing device to indicate the component is at the second position.

Description:
BACKGROUND 
       [0001]    The present disclosure relates generally to lifting devices and, more particularly, to a lifting device that facilitates precise positioning of components during assembly. 
         [0002]    Many known products (e.g., automobiles) are assembled in a progressive manner on an assembly line, along which a subassembly of the product moves from one workstation to next. At some workstations, operators utilize mechanized lifting devices for assistance in lifting and/or positioning heavier components on the subassembly. The heavier components are often manually coupled to the subassembly, or otherwise adjusted, by the operators after having been positioned on the subassembly. 
         [0003]    Accurate positioning of components is typically required to ensure proper assembly and functionality of the products. However, it may be challenging for the operators to accurately, and repeatedly, position the heavier components onto the subassemblies using known lifting devices. It would be useful, therefore, to provide a mechanized lifting device which facilitates precise positioning of components during assembly. 
       BRIEF SUMMARY 
       [0004]    In one aspect, a lifting device for transporting a component from a first position to a second position is provided. The second position is defined relative to a destination datum feature. The lifting device includes a computing device and an arm having a clamp mechanism and a locator mechanism. The arm is selectively movable to engage the component, removably couple the component to the arm using the clamp mechanism, and facilitate transport of the component to the second position. The locator mechanism includes a datum feature that interacts with the destination datum feature to transmit a signal to the computing device to indicate the component is at the second position. 
         [0005]    In another aspect, a method of operating a lifting device is provided. The method includes engaging a component using a clamp mechanism of the lifting device and positioning the engaged component on a pallet using a locator mechanism of the lifting device such that, when a datum feature of the locator mechanism interacts with a destination datum feature of the pallet, the datum feature of the locator mechanism transmits a signal to a computing device of the lifting device to indicate proper positioning of the engaged component on the pallet. 
         [0006]    In yet another aspect, a locator system for a lifting device is provided. The lifting device has a computing device and facilitates transporting a component from a first position to a second position defined relative to a destination datum feature. The locator system includes a base and a datum feature coupled to the base. The datum feature of the locator system is oriented to interact with the destination datum feature to transmit a signal to the computing device to indicate the component is at the second position. 
         [0007]    The features, functions, and advantages described herein may be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which may be seen with reference to the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic illustration of an exemplary assembly system; 
           [0009]      FIG. 2  is a perspective view of an arm of an exemplary lifting device of the assembly system shown in  FIG. 1 ; 
           [0010]      FIG. 3  is a perspective view of an exemplary locator mechanism of the arm shown in  FIG. 2 ; and 
           [0011]      FIG. 4  is a schematic illustration of the locator mechanism shown in  FIG. 3  when the lifting device shown in  FIG. 2  is operated in the assembly system shown in  FIG. 1 . 
       
    
    
       [0012]    Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. Any feature of any drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
       DETAILED DESCRIPTION 
       [0013]    The present disclosure relates generally to lifting devices and, more particularly, to lifting devices that facilitate precise positioning of components during assembly. In the exemplary embodiment, a lifting device includes a locator mechanism that automatically recognizes accurate positioning of a component on a subassembly, and that enables the component to be released from the lifting device only after accurate positioning on the subassembly has been achieved. The exemplary locator mechanism is retractable to enable the lifting device to engage each component without interfering with the fixture on which the component is mounted. Moreover, the locator mechanism is protractible only after the component has been engaged to facilitate accurate positioning of the component on the subassembly, after which the locator mechanism is again retractable to facilitate engaging and positioning another component onto another subassembly. As such, the positioning of components during assembly is quicker, easier, safer, and more precise using the lifting device described herein as compared to known devices. 
         [0014]    As used herein, an element or step recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural elements or steps unless such exclusion is explicitly recited. Moreover, references to “one embodiment” and/or the “exemplary embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
         [0015]      FIG. 1  is a schematic illustration of an exemplary assembly system  100  for use in assembling a product (e.g., an automobile). In the exemplary embodiment, system  100  includes a conveyor  102  by which components (e.g., subassemblies  104 ) of the product (e.g., frames of the automobile) may be transported to and from a workstation  106  generally in an assembly direction  107 . At workstation  106 , a component  108  of the product (e.g., a rear suspension of the automobile) is mounted on each subassembly  104  by an operator  110  using a lifting device  112  including a base  114  and an arm  116  coupled to base  114 . As set forth in more detail below, operator  110  operates lifting device  112  to selectively remove each component  108  from a fixture  118  on which component  108  is supported during transport to workstation  106 . In some embodiments, lifting device  112  is a lift assist, that is, a machine that supports the weight of component  108  while allowing operator  110  to physically move component  108  to a desired location. Fixture  118  may, in one embodiment, be a component of the dunnage by which component  108  was transported to the site of system  100 . Although each component  108  and respective fixture  118  are illustrated as being transported to workstation  106  via a conveyor  120 , it is contemplated that components  108  and fixtures  118  may be transported to workstation  106  in any suitable manner (e.g., each component  108  and fixture  118  may instead be transported to workstation  106  on a cart). In other embodiments, each subassembly  104  and component  108  may be transported to workstation  106  in any other suitable manner that facilitates enabling lifting device  112  to function as described herein. 
         [0016]    In the exemplary embodiment, each subassembly  104  is mounted on a pallet  122  that is movable along conveyor  102 . Each pallet  122  includes at least one location feature  124  that facilitates properly locating subassembly  104  relative to pallet  122 . Because each pallet  122  is the same size and because location feature(s)  124  are positioned in the same location on each pallet  122 , the location of each subassembly  104  on its respective pallet  122  is consistent from one pallet  122  to the next. As set forth in more detail below, arm  116  of lifting device  112  is maneuverable to lift and accurately position each component  108  on a respective subassembly  104  using location feature(s)  124 . In the exemplary embodiment, each pallet  122  includes two such location features  124  in the form of destination datum features (e.g., datum pins  126 ) that are spaced apart from one another on opposite sides of pallet  122  and, hence, on opposite sides of subassembly  104 . In other embodiments, each pallet  122  may have any suitable quantity of location feature(s)  124  arranged in any suitable manner that facilitates enabling lifting device  112  to function as described herein. 
         [0017]      FIG. 2  is a perspective view of an exemplary arm  200  that may be used with lifting device  112 . In the exemplary embodiment, base  114  is supported by, i.e. mounted to, the ground, and each arm  200  is coupled to base  114  such that arm  200  is maneuverable in a three-dimensional space defined by an X-axis, a Y-axis, and a Z-axis which are oriented perpendicularly to one another. As such, in the exemplary embodiment, the X-axis and the Z-axis define a plane oriented substantially parallel to the ground. Similarly, the X-axis and the Y-axis, and the Z-axis and the Y-axis, define planes that are oriented substantially perpendicularly to the ground. Alternatively, base  114  may be mounted to any suitable support structure, and lifting device  112  may include a plurality of arms  200  that are maneuverable relative to one another and/or to base  114  in any suitable manner that facilitates enabling lifting device  112  to function as described herein. 
         [0018]    Each arm  200  includes a frame  202  to which a clamp mechanism  204 , an operator mechanism  206 , and a locator mechanism  208  are coupled. In the exemplary embodiment, frame  202  includes a column  210  that is suspended above, and that is oriented substantially perpendicularly to the ground, such that column  210  has a lower end  212  and an upper end  214 . Clamp mechanism  204  is coupled to column  210  at lower end  212 , and clamp mechanism  204  includes a pair of opposing and stationary contact plates  216  and a pair of movable fingers  218  that also oppose one another, although only one such finger  218  is shown in  FIG. 2 . Locator mechanism  208  is slidably coupled to column  210  at lower end  212  adjacent to clamp mechanism  204  via a linear actuator (e.g., a pneumatic cylinder  220  in the exemplary embodiment). Operator mechanism  206  is coupled to column  210  between lower end  212  and upper end  214 , and in the exemplary embodiment, operator mechanism  206  includes a bracket  222 , a pivot apparatus  224 , and an operator interface  226 . Bracket  222  has a proximal end  228  that is coupled to column  210  at pivot apparatus  224 , and pivot apparatus  224  includes a plurality of levers  230  that are movable under the influence of a rotary actuator and/or via a plurality of linear actuators (e.g., a pair of pneumatic cylinders  232  oriented substantially perpendicularly to one another). Operator interface  226  includes a handlebar  234  that is slidably coupled to a distal end  236  of bracket  222  via a linear actuator (e.g., a pneumatic cylinder  238  in the exemplary embodiment). In other embodiments, arm  200  may have any suitable mechanism in lieu of, or in addition to, clamp mechanism  204  for engaging and lifting component  108  (e.g., in place of clamp mechanism  204 , arm  200  may instead have a clip, a hook, a magnet, and/or a fork that facilitates engaging component  108  and positioning component  108  on subassembly  104  in the manner set forth herein). Alternatively, clamp mechanism  204  and operator mechanism  206  of arm  200  may be configured in any suitable manner that facilitates enabling them to function as described herein. 
         [0019]    In the exemplary embodiment, arm  200  is at least in part manually maneuverable in the three-dimensional space defined by the X-axis, the Y-axis, and the Z-axis using a computing device  115  (shown in  FIG. 1 ) that is communicatively coupled to operator mechanism  206 . For example, in the exemplary embodiment, handlebar  234  has a pair of control grips  240  that are communicatively coupled to computing device  115  for use in manually maneuvering arm  200 . Notably, in the exemplary embodiment, arm  200  is at least in part maneuverable automatically (i.e., without the instruction or assistance of operator  110 ) in the three-dimensional space defined by the X-axis, the Y-axis, and the Z-axis using computing device  115 . As such, to perform the assembly operations set forth in more detail below, arm  200  is manually and/or automatically maneuverable in at least one of the following ways: (a) by displacing clamp mechanism  204 , operator mechanism  206 , locator mechanism  208 , and column  210  in unison along the X-axis, the Y-axis, and/or the Z-axis; (b) by rotating, via pivot apparatus  224 , column  210  (and, therefore, clamp mechanism  204  and locator mechanism  208 ) relative to operator mechanism  206  in the plane defined by the X-axis and the Z-axis; (c) by raising and/or lowering handlebar  234  relative to bracket  222  (and, therefore, relative to column  210 , clamp mechanism  204 , and locator mechanism  208 ) such that handlebar  234  moves substantially perpendicularly to the plane defined by the X-axis and the Z-axis (and, therefore, moves substantially perpendicularly to the ground); and/or (d) by protracting locator mechanism  208  (e.g., moving locator mechanism  208  downwardly relative to column  210  and/or clamp mechanism  204 ) and/or retracting locator mechanism  208  (e.g., moving locator mechanism  208  upwardly relative to column  210  and/or clamp mechanism  204 ) such that locator mechanism  208  is movable substantially perpendicularly to the plane defined by the X-axis and the Z-axis and, therefore, is movable substantially perpendicularly to the ground. Alternatively, arm  200  may be configured in any suitable manner that facilitates enabling arm  200  to function as described herein. 
         [0020]      FIG. 3  is a perspective view of an exemplary locator mechanism  300  for use with arm  200 . In the exemplary embodiment, locator mechanism  300  includes a base  302  and a stem  304  that extends substantially perpendicularly to base  302 , such that base  302  and stem  304  collectively define a substantially inverted T-shaped profile. Locator mechanism  300  also includes a pair of arms  306 , each of which is slidable along base  302  on opposite sides of stem  304  via a linear actuator (e.g., a pneumatic cylinder  308 ). Each arm  306  includes at least one datum feature  309  configured to interact with datum feature(s)  124  of pallet  122  to facilitate proper positioning of components  108  on subassemblies  104 , as set forth in more detail below. In the exemplary embodiment, each arm  306  includes two such datum features  309  in the form of datum sleeves  310  that are each positioned at a distal end  312  of one arm  306  and coupled to a datum sensor  314  (e.g., a datum switch). As such, pneumatic cylinders  308  are operable to selectively adjust (e.g., translate) arms  306  along base  302  to protract datum sleeves  310  (e.g., to cause datum sleeves  310  to move outwardly away from stem  304 ) and to retract datum sleeves  310  (e.g., to cause datum sleeves  310  to move inwardly towards stem  304 ) as desired, thereby selectively increasing and decreasing the spacing defined between datum sleeves  310 . In other embodiments, locator mechanism  300  may have any suitable quantity of datum features (e.g., datum pins, rather than datum sleeves  310  and sensors  314 ) that are adjustably coupled to any suitable structure in any suitable manner that facilitates enabling locator mechanism  300  to function as described herein. Notably, locator mechanism  300  (and locator mechanism  208 ) is a locator system that can be incorporated into newly fabricated (e.g., unused) lifting devices in some embodiments, and can be added onto prefabricated (e.g., already-in-use) lifting devices in other embodiments as a retrofit option. Also, locator mechanism  300  (and locator mechanism  208 ) is usable on lifting devices for placement of a component (e.g., component  108  and/or subassembly  104 ) onto a pallet, and is usable on lifting devices for direct placement of a component (e.g., component  108 ) onto another component (e.g., subassembly  104 ) with or without the use of a pallet (e.g., the destination datum feature(s) described above may be located on any suitable structure and are not restricted to use on a pallet). 
         [0021]      FIG. 4  is a schematic illustration of locator mechanism  300  used on arm  200  of lifting device  112  as lifting device  112  is operated in assembly system  100 . In the exemplary embodiment, locator mechanism  300  is coupled to column  210  so as to be protractible (or movable downwardly away from column  210 ) and retractable (or movable upwardly towards column  210 ) along the Y-axis. With arms  306  of locator mechanism  300  also being protractible (or movable outwardly) and retractable (or movable inwardly) along the X-axis as set forth above, datum sleeves  310  are effectively movable substantially parallel and substantially perpendicularly to the ground (i.e., along both the X-axis and the Y-axis). 
         [0022]      FIG. 4  illustrates an operating state of lifting device  112  in which, by manually operating lifting device  112  at workstation  106  to maneuver arm  200  in the manner set forth above using grips  240 , operator  110  has already engaged and lifted a component  108  from its fixture  118  using clamp mechanism  204 . Operator  110  has also positioned component  108  above a subassembly  104 , which is mounted on its respective pallet  122  on conveyor  102 . However, operator  110  has yet to position component  108  on subassembly  104 . Notably, after operator  110  had already engaged component  108 , and while operator  110  was lifting component  108  from fixture  118  and/or positioning component  108  above subassembly  104 , computing device  115  automatically: (a) protracted locator mechanism  300  (e.g., moved locator mechanism  300  downwardly relative to column  210 ) along the Y-axis; and (b) protracted arms  306  of locator mechanism  300  (e.g., moved arms  306  outwardly relative to stem  304 ) along the X-axis such that datum sleeves  310  and sensors  314  moved from their retracted positions (as indicated by reference numerals  310 ″ and  314 ″) to their protracted positions (as indicated by reference numerals  310 ′ and  314 ′) along the X-axis. Protracted as such, locator mechanism  300  is thus said to be in an “unload” state. 
         [0023]    With component  108  positioned above subassembly  104  and datum sleeves  310  protracted along the X-axis and the Y-axis as illustrated in  FIG. 4 , operator  110  then visually aligns datum sleeves  310  with datum pins  126  of pallet  122  along the X-axis and lowers column  210  (and, hence, locator mechanism  300 , clamp mechanism  204 , and component  108 ) toward subassembly  104  using grips  240 . Once datum pins  126  are inserted into the datum sleeves  310 , sensors  314  transmit a signal indicative of proper positioning to computing device  115 . Computing device  115  in turn illuminates at least one light on handlebar  234  or on locator mechanism  300  (e.g., on sensor(s)  314 ), thereby indicating to operator  110  that proper positioning has been achieved. Computing device  115  then unlocks clamp mechanism  204  and permits operator  110  to release component  108  onto subassembly  104 . Notably, computing device  115  maintains the lock activated and prevents the release of component  108  by operator  110  until proper positioning has been verified (e.g., until computing device  115  receives a signal from sensors  314  indicating that datum pins  126  have been inserted into datum sleeves  310 ). 
         [0024]    After properly positioning component  108  on subassembly  104 , operator  110  can then maneuver arm  200  away from subassembly  104  to remove datum pins  126  from datum sleeves  310  and reengage another component  108  for positioning on another subassembly  104  which arrives at workstation  106  on another pallet  122  via conveyor  102 . While operator  110  is maneuvering arm  200  in this manner, computing device  115  automatically: (A) retracts arms  306  (e.g., moves arms  306  inwardly relative to stem  304 ) along the X-axis such that datum sleeves  310  and sensors  314  move from their protracted positions (as indicated by reference numerals  310 ′ and  314 ′) to their retracted positions (as indicated by reference numerals  310 ″ and  314 ″); and (B) refracts locator mechanism  300  (e.g., moves locator mechanism  300  upwardly relative to column  210 ) along the Y-axis. As such, computing device  115  automatically repositions locator mechanism  300  such that, when viewed from the side elevation of  FIG. 4 , locator mechanism  300  is entirely contained within the footprint  316  of clamp mechanism  304  to facilitate preventing locator mechanism  300  from interfering with fixture  118  when engaging and lifting the next component  108  for positioning on another subassembly  104 . Refracted as such, locator mechanism  300  is thus said to be in a “load” state. 
         [0025]    The above-described embodiments include at least the following technical effects: (1) providing a lifting device with a locator mechanism that automatically and continuously transitions between a protracted “unload” state and a retracted “load” state while the lifting device is operated by an operator to repeatedly lift and position components in an assembly system; (2) providing a lifting device with a locator mechanism that automatically recognizes accurate positioning of a component on a subassembly, and that enables the component to be released from the lifting device only after accurate positioning on the subassembly has been achieved; (3) providing a lifting device with a locator mechanism that is retractable to enable the lifting device to engage each component without interfering with the fixture on which the component is mounted, and is protractible only after the component has been engaged to facilitate accurate positioning of the component on the subassembly, after which the locator mechanism is again retractable to facilitate engaging and positioning another component onto another subassembly; and (4) providing a lifting device which identifies proper positioning of a component on a subassembly, prevents an operator from releasing the component until proper positioning is achieved, and provides an indication of proper positioning to the operator after proper positioning has been achieved. As such, the embodiments facilitate the accurate positioning of components during assembly in a manner that is quicker, easier, safer, and more precise than known methods. 
         [0026]    The methods and systems described herein facilitate accurately and repeatedly positioning components. For example, the methods and systems described herein facilitate assembling a product (e.g., an automobile) by providing assistance to an operator in lifting and precisely positioning heavier components (e.g., the rear suspension assembly of the automobile) on a subassembly (e.g., the frame of the automobile). The methods and systems thereby facilitate less interruption to the operator, which reduces process time and improves safety. Thus, the methods and systems described herein facilitate efficient production overall. 
         [0027]    Exemplary embodiments of lifting devices and methods of operating the same are described above in detail. The systems and methods are not limited to the specific embodiments described herein, but rather, components of the systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. Each method step and each component may also be used in combination with other method steps and/or components. Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. Any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
         [0028]    Some embodiments involve the use of one or more electronic or computing devices. Such devices typically include a controller or processing device such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), a field programmable gate array (FPGA), a digital signal processing (DSP) device, and/or any other circuit or processing device capable of executing the functions described herein. The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and/or a memory device. Such instructions, when executed by the controller or processing device, cause the controller or processing device to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and/or meaning of the terms controller and processing device. 
         [0029]    This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.