Patent Publication Number: US-9888768-B2

Title: Vertical lift system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/196,754 filed Aug. 2, 2011, which claims priority to U.S. Provisional Patent Application No. 61/370,391, filed on Aug. 3, 2010, all of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Most desks and workstations (such as used in offices and laboratories, for example) have fixed tables or countertops. Although there may be fixed shelves above the desk for storing a variety of items, one of the main problems with fixed shelves is the inefficiencies and underutilization of the area above (and below) the desk. It can be difficult, awkward and pose a variety of safety issues for reaching the top or bottom shelves to place objects or items thereon. Many people are forced to use ladders and step stools to place objects on the top shelves, and are forced to crouch, bend or kneel for placing objects on the bottom shelves. This of course causes a host of problems (e.g., safety, ergonomics, efficiencies) associated with using a ladder or step stool, or when climbing and balancing on the ladder when objects are fragile, expensive or heavy, with both hands are being used to hold such objects instead of being used to aid in balancing while ascending the stairs. Therefore, what is needed is the ability to reach the top shelves without a ladder. 
     Another problem with a desk or a workstation countertop is that they are usually made for a person of average height. This poses ergonomic problems for people who are taller, smaller and for those who want more/less space for their legs or for resting their arms thereon. What is needed therefore is a desktop or workstation countertop where the height of the desktop or workstation countertop can be easily adjusted to an individual&#39;s personal preference. 
     Another problem with fixed shelves is the inability to place active equipment or components thereon without using a number of long extension cords, connections and/or pipes. Active equipment refers to machines, tools, devices, appliances or gadgets that use electricity, liquids, gas, vacuum and/or data, for example, and that are being used in an office, running a business, experiments, research, development, design or other laboratory research. There are no convenient outlets located on or near the shelves, making it difficult to plug active equipment into an electrical outlet or connecting them to liquids (e.g., water) or gas (e.g., nitrogen, vacuum, oxygen, helium) or data systems (e.g., the Internet, a local computer network). What is needed therefore is an efficient way to connect to, and to remove and change the outlets, plumbing or services available for a shelving system. 
     During an experiment using active equipment on a fixed shelving system, there arises a problem on how to effectively and efficiently dispense of used waste materials, such as liquids (water, for example) and gases (helium, for example). What is needed is an efficient way of disposing of waste during live and active experiments on a shelving system. 
     What is needed is a shelving system that solves these problems, where a ladder is not needed for the storing objects on the top shelves, where equipment can be easily and ergonomically accessed and connected to power, liquid and gas outlets, and where waste can be efficiently disposed during active experiments. 
     SUMMARY OF THE INVENTION 
     The vertical lift system of the present invention consolidates and efficiently integrates into a single system an ergonomic work area, shelves that can be raised, lowered and extended forward/backward, storage of active equipment, and a height adjustable work surface. This system forms a single, efficient desk, system or other equipment storage system that increases productivity and maximizes storage vertically in a compact footprint. The vertical lift system also allows the monitoring, processing and collecting of data from multiple pieces of equipment. The vertical lift system can connect to local and global networks and systems, such as the Internet or other communication systems or networks, other shared equipment, and can monitor alarm and environment data. 
     In a laboratory type of environment for example, each shelf in the vertical lift system can be considered to be an active work space where all the active work spaces (i.e., shelves) can be put into storage. In other words, each shelf or work space can contain a separate (or combined) laboratory test or experiment, where each test or experiment involves different pieces of equipment or appliances. This allows each shelf (i.e., work surface) to become a work area for active equipment or appliances that can be stored out of the way when another shelf (i.e., work surface) is needed at the user&#39;s ergonomic height. The vertical lift system efficiently permits the equipment to be locally connected or coupled at or near the work space to electricity, data, liquid, gas, air and/or vacuum. So instead of having the experiments at different places on a single work surface, desk or countertop, each experiment can be efficiently and effectively put onto a separate shelf or work surface, and moved up/down for effectively accessing each of the on-going experiments. 
     A vertical lift system is provided and comprises a housing, a lift carriage located inside the housing, having one or more shelves and at least one modular raceway, each modular raceway providing delivery of electricity, data, vacuum, liquid or gas, and a lift system coupled to the lift carriage and the housing, having a control unit that controls movement of the lift carriage inside the housing. 
     A vertical lift system is provided and comprises a housing, a lift carriage located inside the housing, having one or more shelves and at least one modular raceway, each modular raceway providing delivery of electricity, data, liquid or gas, a lift system coupled to the lift carriage and the housing, and a control unit coupled to the lift system. 
     A vertical lift system is provided and comprises a housing, a lift carriage located inside the housing, having one or more shelves and at least one modular raceway, each modular raceway providing delivery of electricity, data, liquid or gas, a work surface connected to the housing and having a unit for moving vertically the work surface, a lift system coupled to the lift carriage and the housing, the lift system controlling vertical movement of the lift carriage, and a control unit for controlling the lift system, for controlling vertical movement of the work surface and for controlling extension of the one or more shelves. 
     An object of the present invention is to provide a vertical lift system that can be lowered/raised so that the top shelves can be easily and ergonomically accessed and objects placed thereon. 
     Another object of the present invention is provide a vertical lift system where the height of a work surface or a countertop can be individually adjusted to an individual&#39;s personal preference. 
     Still another object of the present invention is to provide a vertical lift system where equipment can be easily accessed and connected to electrical, liquid, gas, vacuum and/or data outlets/valves. 
     Yet another object of the present invention is to provide a vertical lift system where the electrical, liquid, gas and/or data outlets/valves can be easily changed from one delivery system to another. 
     Another object of the present invention is to provide a vertical lift system where waste disposal can be easily disposed of during live and active experiments. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed and not to limit it. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
         FIG. 1  illustrates a front, two dimensional view of a vertical lift system according to an embodiment of the present invention. 
         FIG. 2  illustrates a front perspective view of a lift carriage of a vertical lift system according to an embodiment of the present invention. 
         FIG. 3  illustrates a side perspective view of vertical lift system according to an embodiment of the present invention. 
         FIG. 4  illustrates modular raceways according to an embodiment of the present invention. 
         FIG. 5  illustrates a control unit according to an embodiment of the present invention. 
         FIG. 6  illustrates a front perspective view of a height adjustable work surface according to an embodiment of the present invention. 
         FIG. 7  illustrates a view of a leg of a height adjustable work surface according to an embodiment of the present invention. 
         FIG. 8  illustrates a bottom perspective view of a movable shelf according to an embodiment of the present invention. 
         FIG. 9  illustrates a bottom perspective view of a movable shelf that is extended according to an embodiment of the present invention. 
         FIG. 10  illustrates a front perspective view of a lift carriage, work surface and a shelf motion unit for electronically controlling movement of a slidable shelf according to an embodiment of the present invention. 
         FIG. 11  illustrates a bottom perspective view of a shelf motion unit for electronically controlling movement of a slidable shelf according to an embodiment of the present invention. 
         FIG. 12  illustrates a bottom perspective view of a shelf motion unit for electronically controlling movement of a slidable shelf according to an embodiment of the present invention. 
         FIG. 13  illustrates a front perspective view a vertical lift system having a safety sash according to an embodiment of the present invention. 
         FIG. 14  illustrates a side perspective view of a vertical lift system having a switchable glass panel and mountable frame according to an embodiment of the present invention. 
         FIG. 15  illustrates a back perspective view of vertical lift system and one of the slidable shelves according to an embodiment of the present invention. 
         FIG. 16  shows an example configuration of control unit coupled to motors, actuators, and a variety of sensors of vertical lift system according to an embodiment of the present invention. 
         FIGS. 17A and 17B  show a flowchart used by a control unit of the vertical lift system according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a front, two dimensional view of vertical lift system  10  according to an embodiment of the present invention. System  10  comprises housing  12 , lift carriage  14  and lift system  16 . Housing  12  encloses or surrounds lift carriage  14  and encloses or supports lift system  16 . Housing  12  is preferably rectangular in shape, and made from steel, although other shapes and materials can be used. Housing  12  comprises top  18 , base  20  and at least two sides  22 . Each of top  18  and base  20  can comprise four sides (forming a rectangle or square) joined together by nuts/screws, welding, or any other means for securely holding the sides together. Base  20  may rest directly on floor, or may be mounted to feet  24 , where one foot  24  is connected to each corner of base  20 . Base  20  is optional, since sides  22  may form legs to rest on a floor, and alternatively, may also have a steel plate running between the two columns  22  to provide extra support and stability without the need for base  20 . 
     Each of sides  22  attach to top  18  and base  20 . Each side  22  comprises at least two columns, where each end of the two columns attach to top  18 , and the other end of the two columns attach to base  20 . The columns of sides  22  are preferably made from steel or a durable, strong, or heavy-duty metal or other material. Alternatively, sides  22  can comprise four sides (forming a rectangle or square) joined together by nuts/screws, welding, or any other means for securely holding the sides together. It can be appreciated that each of top  18 , base  20  and sides  22  can be covered with or attach to any type of protective shell, cover or decoration, such as metal, plastic or wood, for example. 
       FIG. 2  illustrates a perspective view of lift carriage  14  of a vertical lift system according to an embodiment of the present invention.  FIG. 3  illustrates a side view of vertical lift system according to an embodiment of the present invention. Lift carriage  14  comprises a frame as shown in  FIG. 2 , having a front and back rectangular (or alternatively, square) sections, where the front and back sections are joined via a cross-beam at various places along the top and bottom of the frame. Columns  26  provide support between non-slidable shelves  28  and slidable shelves  30 . Slidable shelves  30  can move out or in manually or automatically under electronic control. Columns  26  are optional, as lift carriage  14  can comprise all non-slidable shelves  28  without any slidable shelves  30 , all slidable shelves  30  without any non-slidable shelves  28 , or a combination of non-slidable shelves  28  and slidable shelves  30 . The frame of lift carriage  14  is preferably made from metal (such as steel for example), but other types of metals and materials may be used, including plastic and wood, for example. 
     As shown in  FIGS. 1-3 , lift carriage  14  moves up/down in the vertical direction inside of housing  12  via lift system  16 . Lift system  16  comprises at least one motor  32 , at least one belt  34 , at least one gear  35 , pulleys  36 , at least one counterweight  38 , at least one clamp  39  and control unit  40 . Motor  32  drives a shaft (located behind gear  35  in  FIG. 2 ) which rotates gear  35 , forcing belt  34  to move in one of two directions. The movement of gear  35  forces belt  34  to move, putting force to rotate pulleys  36  and to move counterweight  38  up/down, resulting in either raising or lowering lift carriage  14 . Counterweight  38  moves in the opposite direction from lift carriage  14 , where counterweight  38  would rise while lift carriage  14  would be lowered, for example. Belt  34  is securely attached or connected at one end to counterweight  38  and securely attached or connected at the other end to clamp  39 . 
     Bearing blocks  42  are attached to the frame of lift carriage  14 , each having wheels which slide along a track formed inside the columns of sides  22 . Through the use of two motors  32 , two belts  34 , two counterweights  38  and bearing blocks  42  as shown in  FIG. 2 , lift system  16  provides a smooth motion either in lowering or raising lift carriage  14  and significantly reduces vibration during the movement. Motors  32  are preferably located at the top  18  of housing  12 . Motors  32  are electronically controlled (via a direct, wired connection or wirelessly) by control unit  40  (not shown) for raising and lowering lift carriage  14  of lift system  16 . It can be appreciated that other types and configurations of lift system  16  could be alternatively used as well, including hydraulics, or motors in combination with chains/belts, for example. 
     Non-slidable shelves  28  and slidable shelves  30  can be used for storing any object or item (e.g., supplies or active equipment in a laboratory). Both non-slidable shelves  28  and slidable shelves  30  are contained inside lift carriage  14 . Each non-slidable shelf  28  and slidable shelf  30  can provide spill containment by having a lip or gutter at the edge of the four corners of the shelf. Each non-slidable shelf  28  and slidable shelf  30  can be adjusted in height along lift carriage  14  by using any variety of pilasters or standards, in combination with clips, supports, brackets (e.g., flanged brackets, lock lever brackets, lever locks), or other commercially available mechanisms. Shelves  28 ,  30  can be made from any durable material, including but not limited to, steel, aluminum, other metals, plastics, wood, glass, epoxy, phenolic or any combination therewith. Slidable shelves  30  are explained in more detail below. 
     Although it is preferred that lift system  16  be electronically controlled via control unit  40 , in other embodiments, lift system  16  may only comprise parts/pieces that are manually (i.e., physically) controlled. For example, instead of having motor  32 , there may be a hand-crank or other hand-operated mechanism attached to a belt, whereupon the turning of the crank will move the belt, gears, pulleys and counterweight. A latch or stop will hold the hand-crank in place so as to prevent rotation. 
       FIG. 4  illustrates modular raceways  44  according to an embodiment of the present invention.  FIGS. 1 and 2  also show modular raceways  44  which are connected inside lift carriage  14 . Modular raceways  44  connect active equipment on shelves  28 ,  30  to the delivery of electricity, plumbing (e.g., gas, water, air, waste or vacuum), and/or data systems or networks. Such electrical, plumbing and data systems and/or networks may be local to the vertical lift system  10 , part of a building&#39;s system, or part of any other public or private network or system. Modular raceways  44  comprise electrical raceways, plumbing raceways, waste (or disposal) raceways, data raceways or any other raceway for delivering specific types of liquid, electricity, gas, vacuum and/or data. Modular raceways  44  are interchangeable, meaning that an electrical raceway could be replaced by a plumbing raceway and visa versa. Also, if four raceways were installed on lift carriage  14 , each raceway could be used to serve a different delivery system, i.e., electrical, water, gas and data. Moreover, it can be appreciated that multiple delivery systems can be combined into a single modular raceway (e.g., plumbing and gas provided in one modular raceway). Another example may be to combine outlets for electrical power and data systems into a single modular raceway. 
     These modular raceways  44  connect to a source&#39;s (e.g., workstation&#39;s or building&#39;s) plumbing, electrical or data systems at the top of the raceway, through the top of lift carriage  14  and then through the top  18  (or alternatively the sides  22 ) of vertical lift system  10  to connect to the source. It can be appreciated that modular raceways  44  can also connect at the bottom of lift carriage  14  and through the bottom and/or side of system  10 . Each modular raceway  44  connects to lift carriage  14  via any type of connection, including snap locks, clips, buckles, nuts/bolts, or any commercially available means for attaching modular raceway  44  to lift carriage  14 . 
     As shown on  FIG. 4 , a plumbing raceway  44  comprises at least one pipe (flexible or hard, metal or plastic) with a variety of plumbing valves  46 . Plumbing valves  46  can be interchangeable, removable, and/or quick-connect fixtures and can be located above and/or underneath shelves  28 ,  30 . Plumbing valves  46  can be found inside lift carriage  14  and are capable of being connected to a building&#39;s or laboratory&#39;s water, gas or other liquid/gas/air/vacuum systems via pipes or hoses which run through the top of lift carriage  14  and through the top or sides of vertical lift system  10 . Plumbing valves  46  are connected to the pipes inside modular raceway  44 . A separate tube or pipe is used for connecting plumbing valves  46  to an input valve on the equipment stored on shelves  28 ,  30 . In one embodiment, plumbing valves  46  may include an extendable fixture that extends from modular raceway  44  to the equipment being connected. 
     Plumbing valves  46  provide an efficient system and method for attaching the water and/or gas systems to equipment that is stored on shelves  28 ,  30 . Although the plumbing valves  46  are oriented in  FIG. 4  in a position facing inward to the center of lift carriage  14 , valves  46  may also be oriented in a direction perpendicular to that shown in  FIG. 4  or in any other position. Plumbing valves  46  may be made from metal or plastic, and can have a locking mechanism to lock the tube or piping from the equipment onto the plumbing valve  46 . Plumbing valves  46  can also have a local shut off lever, push or lift to turn safety features, or any other commercially available feature(s). 
     Modular raceways  44  may also house electrical outlets and data connections. The electrical outlets can be any configuration commercially available including NEMA, while the data outlets can be Ethernet, USB or any other type of data connection outlet. The electrical outlets provide an easy and efficient way to plug electrical or electronic equipment into a power source or into a data source (such as the Internet, a computer, a server or any other type of data device, service, system or network). A power modular raceway  44  is wired at the top of lift carriage  14  so it can be easily connected to the power or data source (e.g., laboratory&#39;s or building&#39;s electrical power source and data lines). Modular raceway  44  may have quick connections, such as a twist lock feature for example, but could also be hard connected to the building system rather than modular if so desired. Optionally, the equipment may be connected to a wireless server or to a wireless local access network, thus eliminating the need for data connection in the modular raceways  44 . 
     Modular raceways  44  may also comprise drainage pipes that can be connected to drainage bins located at the bottom of vertical lift system  10 . Drainage bins can be used for capturing waste from laboratory experiments or otherwise. Drainage bins are made of materials used for capturing a particular waste, whether made of metal or plastic materials, and for collecting liquids or gas or a combination thereof. The floor of vertical lift system  10  may be dished to contain any accidental spills and for easy cleaning. 
     Modular raceways  44  are located on lift carriage  14 , so when lift carriage  14  moves up/down, modular raceways  44  also concurrently move up/down. This provides the advantage of knowing that the active equipment would not be disconnected from their electrical, liquid, gas data or other source due to the movement of lift carriage  14  in system  10 . This also provides a convenient way to connecting active equipment to a source without undue use of extension cords, wires, pipes and/or tubes. 
     In an alternative embodiment, modular raceways  44  could be fixed inside lift carriage  14 , meaning that modular raceways  44  are not interchangeable and/or removable. This may be due to certain code rules and regulations enacted by local, state and federal jurisdictions. For example, vertical lift system  10  may contain a permanent modular raceway  44  for housing electrical outlets and wires. In another example, vertical lift system  10  may contain a permanent electrical raceway and a permanent liquid raceway for waste. In another alternative embodiment, modular raceways  44  may have a combination of permanent raceways and interchangeable raceways. 
     In another embodiment, there may be a strip of outlets that runs along the back, sides and/or the bottom of the shelf or may be integrated into the shelf itself. This strip or strips would connect to the modular raceways  44 , or connect wirelessly, or with wires to the building service delivery system. This configuration effectively multiples the number of outlets for each outlet on the modular raceways  44 . For example, instead of having one electrical outlet per each shelf, a power strip having multiple outlets could be placed along the back or sides of each of the shelves, thus multiplying the number of available outlets per one outlet on the modular raceway. These power strips permit each piece of equipment or appliance to connect to their own power outlet. Instead of having one electrical outlet for all pieces of equipment and appliances on a single shelf (i.e., work surface), multiple outlets become available for use by the equipment and appliances. Similar strips can also be used for providing multiple outlets for liquids, gas, air, vacuum, waste, etc. 
       FIG. 5  shows a control unit  40  according to an embodiment of the present invention. Control unit  40  may or may not be part of lift system  16 , but instead may be a separate unit apart from the lift system  16 . Lift system  16  brings each piece of equipment that is stored on shelves  28 ,  30  in a safe and smooth vertical motion. Lift carriage  14  moves in the vertical direction (up/down or raise/lower) under the control of control unit  40 . Control unit  40  can comprise one or more computers or servers. Control unit  40  not only controls lift carriage  14  and slidable shelves  30 , but also all other functions and features of vertical lift system  10 , including for example, turning on/off interior and exterior lights, activate/deactivate switchable glass, power vertical lift system  10  on/off, and adjust the height of work surface  70 . 
     Control unit  40  comprises processor(s)  50 , memory  52 , input unit(s)  54 , sensors  56 , output unit(s)  58  and communications unit(s)  60 . Processor  50  can be any computer processor that is commercially available. There can be one or more processors  50 , including having a processor dedicated to one or more particular functions. For example, there may be one processor  50  for controlling lift carriage  14 , and a separate processor  50  for controlling the safety features and functions of vertical lift system  10 . 
     Memory  52  can comprise any type and number of computer memory devices that are commercially available, such as internal or external memory disc drives and flash drives, for example. Memory  52  is primarily used to storing computer software, programs, applications and/or data that are executed on processor  50 . Memory  52  may be incorporated into and part of processor  50 , or may be a separate unit. 
     Input unit(s)  54  can comprise one or more buttons, keypads, joy sticks, mouse(s), keyboards or touch screens or other types of input devices used in a computer system. Each of the input unit(s)  54  can be made of metal, plastic or any other material suitable for the particular function, and may even light up and be visible when the environment is dark. Input unit(s)  54  could be digital, touch screen, switch or push button types and can have user definable set points or purposes. 
     Input unit(s)  54  can be located on the front, back or sides of vertical lift system  10 . In one example of input unit  54  comprising a number of buttons, one button may be used for raising lift carriage  14 , one button for lowering lift carriage  14 , one button for an emergency stop, one or more buttons for turning on different lights mounted inside system  10  or the room, buttons for lifting an desk top, countertop or work surface, and buttons for opening and closing sliding doors or shelves. A keypad or keyboard may be used for entering a personal code to gain authorized access to system  10 . All the features previously described in conjunction with the buttons and keypads, can be also programmed into and performed by a touch screen display device. A touch screen can also be programmed to monitor and manage any function or feature of vertical lift system  10 . 
     Sensors  56  (or encoders  56 ) monitor any type of a change in a condition in vertical lift system  10  and determine the position/location of where lift carriage  14 , slidable shelves  30  and work surface are separately located and in relation to each other. Sensors  56  can be any type of sensor or encoder, including for example, position sensors which can be used for detecting the location of the shelves  28 ,  39  or lift carriage  14  within vertical lift system  10 , or the position of the work surface. There may be encoders for each motor used in vertical lift system  10 , each encoder would determine the location or position of the lift carriage  14 , slidable shelves  30  or work surface. Heat sensors can be used for detecting the temperature inside or around vertical lift system  10 , such as used for detecting a fire for example. Gas sensors may be used for detecting the presence of a particular gas within vertical lift system  10 , such as for detecting the release of a toxic or non-toxic gas. Water sensors may be used for detecting whether water is leaking in one of the modular raceways. Pressure sensors may be used for detecting whether pressure is being maintained on particular water or gas pipelines in modular raceways  44  for example. Electrical sensors may be used for detecting whether a constant current is being provided, so as to access a backup electrical power source in case of a power outage. 
     Output unit(s)  58  comprise any type and one or more monitors, display devices, lights, ventilation vents or fans, and motors (for raising/lowering lift carriage  14 , raising/lowering an adjustable work surface, and for controlling movement of slidable shelves  30 ). There can be multiple display devices located on vertical lift system  10  where such display devices can be located on the front, back and sides of system  10 . When a touch screen is used for input unit  54 , the touch screen may concurrently serve as output unit  58 . 
     Communications unit(s)  60  can be a wired or wireless connection and/or port for connecting to any local, remote, public and/or private remote communications and/or computer networks, such as the phone networks (e.g., landline, cellular, satellite), local access computer networks, the Internet and any other type of wired or wireless networks or systems. There may be one or more communication units or ports  60  connected or coupled to control unit  40 . 
     Via control unit  40 , lift carriage  14  can be lowered so that any one of the upper shelves  28 ,  30  can be easily reached without a ladder. This enables users to place equipment and/or supplies on shelves  28 ,  30  in an efficient manner and without straining to reach the upper shelves. From these examples, any one can efficiently and easily place items and equipment on any of the shelves  28 ,  30 . 
     Although vertical lift system  10  can be a stand-alone system, vertical lift system  10  can easily fit behind all types of conventional desks to provide a vertically movable unit for storing a variety of objects. Vertical lift system  10  may also have a fixed or a height adjustable work surface  70 . Work surface  70  is similar to a desk top or countertop. If work surface  70  is manually adjustable up/down, pilasters or standards can be attached to the front (or alternatively, the side or back) of housing  12 , in association with clips, supports and/or brackets (e.g., flanged, lock lever, lever lock) to hold a flat surface thereon to create work surface  70 . This manually adjustable configuration allows for adjustment of work surface  70  by manually raising or lowering the brackets and/or supports to different locations on the pilasters, standards or along the housing  12 . 
       FIGS. 6-7  illustrate a height adjustable work surface according to an embodiment of the present invention. Up/down buttons associated with control unit  40  can be located on the front, top or side of work surface  70  and can be used for raising or lowering the height of work surface  70 . Alternatively, a touch screen of control unit  40  can display the current height, and a user could select a different height of work surface  70  via arrows (up/down arrows) or entering a number representing the actual height of work surface  70  from the floor. Control unit  40  can also be programmed to store the preferred height for each user, where the user could choose this setting and work surface  70  would then be automatically adjusted to the height preferred by the user. 
     As shown in  FIGS. 6 and 7 , adjustable work surface comprises work surface  70 , movable leg sections  72 , fixed leg sections  74 , one electric motor  76  for each leg and sensors  78 . There are at least two legs that support work surface  70 . Each leg has leg section  72  that fits inside and moves inside fixed leg section  74 . Control unit  40  controls the movement of both leg sections  72 , which are raised or lowered together via motor  76 . In each leg, motor  76  is attached to a drive shaft (not shown) that connects to an actuator (not shown) and connects to leg section  72 . To raise work surface  70 , control unit  40  signals both motors  76  (one in each leg) to rotate their drive shaft in the same direction, so that the actuator in each leg will rise together, thus raising work surface  70  in a smooth motion. To lower work surface  70 , control unit  40  signals both motors  76  to rotate the drive shaft in the opposite direction, where both actuators will lower concurrently, thus lowering work surface  70  in a smooth motion. In an alternative embodiment, instead of using motors, drive shafts, actuators, hydraulic systems or any other mechanical and/or electrical systems that can raise/lower work surface  70  could be used as well. 
     Work surface  70  is preferably made from steel (or similar material) for durability and vibration control, although other materials and metals could be used as well. One or more of the sensors  56  determine the height of work surface  70  which is sent to control unit  40 . Control unit  40  can then raise/lower lift carriage  14  so that non-slidable shelves  28  and/or slidable shelves  30  are aligned with the top of work surface  70 . Slidable shelves  30  can be pulled out or extended from inside lift carriage  14  either manually or via a power source, so that the bottom edge of slidable shelves  30  clears the top of work surface  70  by a small distance, for example, such as less than a half of an inch. By allowing the slidable shelves  30  to extend over work surface  70 , it provides an easier, safer, more ergonomic way for loading and unloading equipment (and other objects or items) from slidable shelves  30 . 
     Once non-slidable shelves  28  and slidable shelves  30  have been installed into lift carriage  14 , control unit  40  will run an initial configuration software program in conjunction with one or more sensors  56  to determine the number and location of each of the shelves  28 ,  30  and the height of a work surface and to configure or set initially any other feature or function that is performed or monitored by control unit  40 . Alternatively, user-defined set points can be individually programmed for locations of specific shelves  28 ,  30 , for specific work surface  70  height locations or for any other custom defined adjustments. Once set, specific shelves  28 ,  30  can be selected via input unit  54  of control unit  40 , whereupon lift carriage  14  will move up/down so that the selected shelf will align with the top of work surface  70 . 
     Slidable shelves  30  either slide manually or automatically via control unit  40 .  FIGS. 8-9  illustrate a bottom perspective of one side of slidable shelf  30 . To extend slidable shelf  30  manually, a person pulls on shelf arm  80 , which in turn forces bands  82  to retract around a pair of dual motion pulleys  84  forcing shelf  30  to slide along shelf slide  86 .  FIG. 8  illustrates slidable shelf  30  when retracted inside lift carriage  14 , while  FIG. 9  illustrates slidable shelf  30  when extended in the forward position from lift carriage  14 . The dual motion pulleys  84  allow shelf  30  to extend twice the distance of shelf arm  80 . Dual motion pulleys  84  can be used in the manual and/or the electronic configuration. In an alternative embodiment, shelves  30  may slide manually or automatically in the reverse direction, meaning instead of forward sliding, shelves  30  would be reverse sliding toward the back of vertical lift system  10 . In yet another embodiment, shelves  30  may slide both in the forward and rearward directions via manual or electronic means. 
       FIGS. 10-12  illustrate a shelf motion unit for electronically controlling movement of slidable shelf  30 . The shelf motion unit comprises actuator motor  100 , drive shaft  102  and actuators  104 . An actuator is a mechanical device for moving or controlling the movement of slidable shelf  30 . Each slidable shelf  30  has a pair of shelf arms  80 , one shelf arm  80  is shown in  FIG. 11 . At the end of shelf arm  80  is an “L” shaped piece, which engages or passes through the associated shelf receiver  106  (located underneath work surface  70 ) when lift carriage  14  is raised/lowered. After lift carriage  14  has moved so that the selected shelf  30  is properly aligned with work surface  70 , each L-shaped piece of the shelf arm  80  engages, couples or connects to its respective shelf receiver  106 . Actuator motor  100 , under control of control unit  40  which receives a command to extend slidable shelf  30 , then starts to rotate drive shaft  102  forcing actuator  104  to move along track  108 , pulling slidable shelf  30  along track  110  (one on each side of shelf  30 ) from inside lift carriage  14 . Motor  100  will stop once slidable shelf  30  has been fully extended. 
     When slidable shelf  30  needs to be retracted, an operator will indicate such operation to control unit  40  through any of the input units  54  previously mentioned, such as a button, or a touch screen button, for example. Thereupon, control unit  40  will signal to actuator motor  100  to rotate drive shaft  102  in the opposite direction, thereby pushing actuators  104  which in turn push slidable shelf  30  back into lift carriage  14 . Once fully retracted, control unit  40  can raise/lower lift carriage  14 , where shelf arms  80  can safely pass through shelf receivers  106 . 
     The command to pull or push slidable shelf  30  can be automatically programmed into control unit  40  for each slidable shelf  30 . Control unit  40  can be configured to automatically pull out a selected one of the slidable shelves  30 , or can be configured to only pull out the shelf  30  upon a separate command once the selected shelf  30  has been aligned with work surface  70 . The command to push slidable shelf  30  which had been extended can occur either when commanded to retract, or when a different slidable shelf  30  is selected. Control unit  40  will not permit lift carriage  14  to move up/down when one of the slidable shelves has been extended. 
     In alternative embodiments, shelf receiver  106  may retract when lift carriage  14  is being raised and lowered, and will only extend when the selected shelf  30  is moving into position. In another embodiment, instead of using an “L” shaped shelf arm  80  to engage shelf receiver  106 , other types of connections could be used as well, such as snap lock/release mechanisms for example, so that shelf arms  80  do not have to pass through shelf receivers  106  when carriage lift  14  is moving up/down. 
     The front and back of vertical lift system  10  can have a clear, vertically-rising safety sash, glass doors, or any other types of safety panels.  FIG. 13  illustrates a front perspective view of a safety sash according to an embodiment of the present invention. The safety sash can be made from glass, plastic, acrylic or any other durable material. The safety sash helps to protect people from moving components (i.e., the lift carriage  14 ) and helps to limit energy loss from ventilation. 
       FIG. 14  illustrates a side view of vertical lift system containing switchable glass  120 . Switchable glass  120  is mounted on the exterior sides of vertical lift system  10 . Switchable glass  120  is commercially available and converts transparent viewing panels to opaque for dry-erase writing and privacy (i.e., to conceal components, equipment or cords). The operation to switch between glass  120  being transparent or clear to being opaque (e.g., white or another color) is controlled via control unit  40 . Switchable glass  120  can be marked on by using commercially available erasable ink, this ink being similar to what is being used for marking or writing on white boards. The clear glass  120  can be changed to an opaque surface by activating an electric current from a switch at control unit  40 . In an alternative embodiment, switchable glass  120  could be a computer display surface which has the ability to capture any writing on its surface and convert it to a digital format, viewable on a computer monitor or other display device. 
     Switchable glass  120  is mounted to the side of vertical lift system  10  via mountable frame  122 . Mountable frame  122  can be used for easily adding accessories such as exterior shelving, large screen displays, pegboards, coat hooks or other items. Exterior shelving and large screen displays would have adjustable, locking mechanisms for locking the shelves and displays into the mountable frame  122 . The mountable frame  122  could be powered for low voltage accessories or could contain accommodations for power and data cords. 
       FIG. 14  also shows shell  124  on the exterior of vertical lift system  10 . The shell  124  is made from materials such as metals, plastics or wood for example. Shell  124  may be decorated or plain, and may have one or more colors and/or decorations. 
       FIG. 15  illustrates a back perspective view of vertical lift system and one of the slidable shelves according to an embodiment of the present invention. On the back of the frame of lift carriage  14  and also on the backside of the front of the frame of lift carriage  14 , there are evenly spaced pins  130  that stick out from the frame of lift carriage  14 . Four pins  130  on each corner/column of the frame of lift carriage  14  are located on the same horizontal plane to each other, where two pins  130  on the back of frame have a corresponding set of two pins  130  on the backside of the front of the frame of lift carriage  14 , and where all four pins (one at each corner) are located on the same horizontal plane. Each slidable shelf  30  has eight holes, two holes in each corner of the shelf  30 . Eight pins  130  fit through eight holes of each slidable shelf  30 , two holes per bracket. Two screws  132  are then fitted through the bracket on each corner of the back side of slidable shelf  30 , where they align with corresponding holes in the frame of lift carriage  14 . These four screws  132  securely attach slidable shelf  30  to carriage lift  14 . To readjust shelf  30 , the screws are  132  unscrewed, then shelf  30  is pulled from the back of carriage  14 , realigning with a pair of pins  130  on each corner of carriage lift  14 . Shelf  30  is then pushed into lift carriage  14  and the four screws  132  are attached to one of two brackets and lift carriage  14 . Although two pins/holes are used as shown in  FIG. 15  for each corner of shelf  30 , it can be appreciated that one or more pins/holes can be used as well. 
       FIG. 16  shows an example configuration of control unit coupled to motors, actuators, and a variety of sensors of vertical lift system according to an embodiment of the present invention. Control unit  40  communicates electronically (wired or wirelessly) with motors  32 ,  76 ,  100  and actuators  104 . Control unit  40  communicates electronically with a variety of sensors  56 . Each of the sensors  56  indicate and determine one or more conditions or functions. Although  FIG. 16  shows some of sensors  56 , it can be appreciated that this is just one example of the many sensors that can be used by vertical lift system  10 . 
     Example of some of the sensors  56  include shelf sensors  140 , upper limit sensor  142 , work surface crash (left and right) sensors  144 , work surface obstruction sensor  146  and lower limit sensor  148 . One or more shelf sensors  140  indicate where a particular shelf  28 ,  30  is located, whether a shelf if slidable or not, whether the shelf is extended/retracted, whether there are objects located on the shelf and whether there are objects that would prevent the shelf from retracting. Upper limit sensor  142  determines whether lift carriage  14  has been fully raised, where the bottom shelf is flush with the work surface  70 . Work surface crash left/right sensors  144  determine whether there is crash of a shelf onto work surface  70 , or some other condition which would indicate a crash. Work surface obstruction sensor  146  determines whether there are objects located on work surface  70  which would prevent a slidable shelf  30  from being extended. Lower limit sensor  148  determines whether lift carriage  14  is at the lowest point—where lift carriage  14  can not be further lowered inside vertical lift system  10 . 
     There are other sensors  150 ,  152 ,  154  for determining whether a front sash, a rear upper sash and a rear lower sash are properly closed. Control unit  40  may be programmed to prohibit lift carriage  14  from moving if these sensors  150 ,  152 ,  154  indicate that the respective sash is open. Having the sashes closed during movement of lift carriage  14  helps to prevent body parts, including fingers, wrists and arms from being caught inside lift carriage  14  when it is moving. 
       FIGS. 17A and 17B  show a flowchart used by a control unit of the vertical lift system according to an embodiment of the present invention. After power is turned on in step  202 , control unit  40  in step  204  performs an initial system diagnostic and initialization. Control unit  40  will check all electronic components to determine whether they are properly functioning and that there are no errors. Control unit  40  will also determine whether control unit  40  was properly shut down the previous time and/or whether there was an emergency shutdown. Control unit  40  will also check all sensors to confirm that all sashes/doors are closed and that vertical lift system can operate safely. Control unit  40  will further cycle through carriage lift  40  and determine which shelves  28 ,  30  are installed and their location, the height of work surface  70  and whether a shelf is slidable or non-slidable. Control unit  40  will move carriage lift  14  so the shelf identified as the bottom shelf is flush with the work surface. If there is any error, control unit  40  will display the error message(s) on an output unit  58  so that the parts/piece can be fixed. Some errors may be over-ridden, but in general, all errors should be fixed before vertical lift system  10  can be operated by a user and/or computer. 
     After system initialization, one of the input units  54  will wait for a command or instruction in step  206 . The commands or instructions include any of the functions or features provided by vertical lift system, including for example, turning on/off internal and exterior lights, turning on/off vents, vertically moving lift carriage  14  to a particular shelf, extending/retracting a particular shelf and moving vertically the height of the work surface  70 . There are many other commands and instructions than those just listed. The command or instruction is sent from one of the input units  54  and/or communication units  60  to control unit  40 . 
     In step  208 , if control unit  40  determines that the command is to raise/lower lift carriage  14  (e.g., a selection of a particular shelf), then control unit  40  checks the related sensors  56  in step  210 , and if the related sensors do not indicate any errors or problems in step  212 , then control unit  40  communicates with one or more motors  32  to raise/lower lift carriage  14  to the desired position in relation to work surface  70 . If there are errors or problems noted by the sensors in step  210  and control unit  40  determines in step  212  that lift carriage  14  cannot be moved, then control unit  40  sends in step  213  an error message to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for a command. 
     After lift carriage  14  has been successfully moved to the proper or predetermined position of the selected shelf in step  214 , control unit  40  checks to determine in step  216  whether the shelf is a slidable shelf, and if so, determines whether the slidable shelf should be automatically extended in step  216 , If the slidable shelf should be automatically extended, control unit  40  checks in step  218  the appropriate sensors  56 , determines in step  220  whether sensors  56  indicate whether slidable shelf  30  can be extended without any problems, and if ok, extends in step  222  the slidable shelf  30  by controlling the shelf motor  100 . Control unit  40  then sends in step  224  a message of the shelf extension to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. If the slidable shelf cannot be automatically extended in step  216 , control unit  40  displays in step  224  a successful completion of the movement of lift carriage  14  on one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for another command. Also, if the slidable shelf cannot be extended in step  220 , control unit  40  sends in step  213  in an appropriate error message to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. 
     If the command is not for raising/lowering lift carriage in step  208 , control unit  40  determines in step  226  whether the command is for extending a slidable shelf. If the inputted command is for extending a slidable shelf, then control unit  40  checks in step  218  the appropriate sensors  56 , determines in step  220  whether sensors  56  indicate whether slidable shelf  30  can be extended without any problems, and if ok, extends in step  222  the slidable shelf  30  by controlling shelf motor  100 . Control unit  40  then sends in step  224  a message of the shelf extension to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. If the slidable shelf cannot be extended in step  220  due to a failure noted by one of the sensors  56  or otherwise, control unit  40  sends in step  213  in an appropriate error message to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. 
     If the command is not for extending a slidable shelf in step  226 , control unit  40  determines whether the command is for retracting the slidable shelf in step  228 . If command matches the command for retracting a slidable shelf, then control unit  40  checks in step  230  the appropriate sensors  56 , determines in step  232  whether sensors  56  indicate whether slidable shelf  30  can be retracted without any problems, and if ok, retracts in step  234  the slidable shelf  30  by controlling the shelf motor  100 . Control unit  40  then sends in step  224  a message of the shelf retraction to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. If the slidable shelf cannot be retracted in step  232  due to a failure noted by one of the sensors  56  or otherwise, control unit  40  sends in step  213  an appropriate error message to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. 
     If the command is not for retracting a slidable shelf in step  228 , control unit  40  determines whether the command is for raising/lowering work surface  70  in step  236 . If the command matches the command for raising/lowering work surface  70 , then control unit  40  checks in step  238  the appropriate sensors  56  including whether a shelf had been extended. Control unit  40  then determines in step  240  whether sensors  56  indicate whether work surface  70  and lift carriage  14  can be raised/lowered without any problems, and if ok, in step  242  control unit  40  first retracts an extended shelf, raises/lowers work surface  70 , and then lastly readjusts or raises/lowers lift carriage  14  so that work surface  70  is in the correct or predetermined position in relation to the current shelf of lift carriage  14 . Upon successful completion, control unit  40  then sends in step  224  a message to one of the output units  58  and/or communication units  60 , and finally returns to step  206  to wait for the next command. If the slidable shelf cannot be retracted or work surface  70  and/or lift carriage  14  cannot be raised/lowered in step  232  due to a failure noted by one of the sensors  56  or otherwise, control unit  40  sends in step  213  in an appropriate error message to one of the output units  58  and/or communication units  60 , and returns to step  206  to wait for the next command. 
     If the received command is not for raising/lowering work surface  70  in step  236 , control unit  40  determines whether the command is for powering down/off vertical lift system  10 . If the command is for powering down, control unit  40  proceeds in step  246  to start the power down routines or procedures, ensuring that processors and memory are protected during the sequence. Once all the power down procedures have been executed, power is turned off in step  248  to the vertical lift system  10  and method  200  terminates. 
     If the received command is not for powering down system  10 , then control unit  40  determines in step  250  what other function needs to be performed. Other commands include all other functions and features of vertical lift system  10 , including for example, turning on/off interior and exterior lights, switching on/off switchable glass  120 , etc. Control unit  40  may optionally confirm the command in step  252 , and if confirmed, will check in step  254  the appropriate sensors  56  and perform the commanded function. Control unit  40  then displays that the command was successfully completed in step  224 . 
     In alternative embodiments, control unit  40  may additionally confirm with the user the execution of the desired command in steps  212 ,  220 ,  232  and  240 , before the command is actually executed and performed. In another alternative embodiment, the sequence of what command is checked in steps  206 ,  208 ,  226 ,  228 ,  236 ,  244  and  250  can be in a different order than what is shown in  FIGS. 17A and 17B . For example, steps  208  and  226  can be checked before step  206 . Another example is that step  244  is checked first, followed by steps  206 ,  208 , etc. 
     While the inventions have been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. Thus, it is intended that the present invention cover the modifications and any and all variations of these inventions and their equivalents. Additional features and advantages of the inventions will be apparent from the description, or may be learned by practice of the inventions. The objectives and other advantages of the inventions will be realized and attained by the structure particularly pointed out and described in the written description, the appended drawings and any other materials accompanying the submission of this provisional patent application. It is further to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the inventions and not to limit it.