Abstract:
The present invention provides actuation mechanisms that incorporate a transmission assembly that allows the mechanisms to cause actuation of workpieces according to a plurality of transmission modes (e.g., at least one forward transmission mode and at least one reverse transmission mode) on demand. Motion, direction, and/or force can be controlled by selecting the corresponding transmission mode. The mechanisms preferably are trigger-actuated by hand (i.e., manually) to cause movement of a workpiece in a desired direction. Desired directions can be linear or nonlinear. The same hand used for trigger action can also be used to change transmission modes in many modes of practice, even while using substantially the same grip used for trigger actuation. In other instances, actuation can be automated rather than manual. Preferably, both actuation and witching among transmission modes can be accomplished with one hand, even while maintaining substantially the same grip that is used for actuation.

Description:
STATEMENT OF PRIORITY 
       [0001]    The present patent application claims priority from U.S. Provisional patent application having Ser. No. 61/679,289, filed on Aug. 3, 2012, by Pfahnl et al. and entitled DISPENSING AND ASPIRATING SYSTEM INCLUDING A SYRINGE HOLDING AND ACTUATION DEVICE. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to systems and methods for controlling the motion of two elements using a compact transmission whose modes of actuation can be easily selected on demand. An example application of the invention includes injecting and/or aspirating fluids using a syringe in combination with a syringe holding and actuation device. More specifically, the present invention relates to such systems and methods in which a holding and actuation device includes a compact transmission to allow a user to easily select the direction of the motion, e.g., an actuating mechanism can be moved forward or in reverse on demand. In the case of fluid delivery, it is possible to switch between the aspiration or dispensing modes of function on demand. 
       BACKGROUND OF THE INVENTION 
       [0003]    Syringes are available in a variety of sizes and are intended to dispense (inject) as well aspirate (extract) a variety of substances, most often fluids but also dispersions, gels, solids such as powders, or gases. Syringes are used to inject or aspirate fluid in several therapeutic and diagnostic medical procedures such as the following illustrative examples:
       1) Centesis Procedures—including Thoracentesis (removal and optional analysis of fluid in the chest, Paracentesis (removal and optional analysis of fluid in the abdomen), Pericardialcentesis (removal and optional analysis of fluid from the pericardial space around the heart), and Arthrocentesis (removal and optional analysis of fluid from a joint).   2) Abscess Aspiration—removal and optional analysis of fluid collection sites common in the body particularly the breast, brain or kidneys.   3) Contrast Media Injection—special fluid to better visualize blood vessels for cardiology procedures. Aspiration is used to verify the needle puncture into a vasculature, and injection is used to deliver the contrast media into the vasculature.   4) Exchange Transfusions—including slow and careful replacement of blood for adult and pediatric blood diseases.   5) Surgical Wound Irrigation—including high velocity cleansing of traumatic injuries. A syringe aspirates saline, for example, from a reservoir and irrigates a wound site.       
 
         [0009]    The nature of these procedures typically involves extensive manipulation of the syringe and stabilization of the injection/aspiration site. These tasks are more difficult with high viscosity fluids and/or larger syringes. 
         [0010]    Syringes can be manually operated with one or two hands, can be manually operated with the assistance of a holding/actuation accessory, or can be used with a variety of automatic devices which aide in controlling the movement of the substance within the syringe. Automation comes with additional cost, size, and maintenance disadvantages compared to manual activation. 
         [0011]    Larger size syringes, such as 60 mL ones, are common and well-suited for many procedures. However, larger sized syringes are more challenging to use manually with one hand, even when used in combination with conventional actuation accessories. This difficulty could compromise patient safety, delivery and aspiration accuracy, and/or extend procedure times. Having a second person assist in helping resolve these issues increases procedure cost. 
         [0012]    Syringe accessories in the form of hand pieces or devices have been described and developed that address some of the challenges associated with using syringes to accomplish aspiration. A handheld device used with syringes to provide aspiration function is depicted in patents such as U.S. Pat. No. 5,469,860 and USD337821. A commercially available device is available from Inrad, Inc. (Kentwood, Mich.) under the trade designation Aspiration Biopsy Syringe Gun. Several devices also have been described that are used with syringes to dispense syringe contents. See, e.g., USD576273. 
         [0013]    Some syringes include features to assist with single handed aspiration. These features include loops or rings to facilitate finger and thumb action. These features can facilitate both dispensing and aspiration. Several variations of an early control syringe exist. See, e.g., U.S. Pat. No. 4,516,969. 
         [0014]    Commercially available devices with trigger-actuated ratchet mechanisms are used in so-called caulk guns for dispensing adhesives and caulking materials from prefilled cartridges. The guns and cartridges are available in different sizes. Illustrative products are and manufactured by companies such as 3M Co. (St. Paul, Minn.) and Henkel Corp. (Rocky Hill, Conn.). A recent patent US7757904B2 is an example of such a device for caulk cartridges. 
         [0015]    Commercially available bar clamping devices exist that utilize ratchet mechanism principles. Examples are US8074340B2 and U.S. Pat. No. 4,926,722. Some of these clamps can be reconfigured to a spreading bar clamp as described in U.S. Pat. No. 5,009,134. These devices illustrate how high forces can be used to create a clamping or spreading motion. A bar clamp that uses a switching mechanism to select between clamping and spreading functions is described in US7325797B2. A third example device is marketed by Avanca Medical Devices, Inc and described in US7967793B2. This device allows the dispensing and aspiration of a syringe with a single hand. A fourth example is a balloon inflation device that utilizes a threaded plunger that is rotated clockwise or counterclockwise to advance or retract the plunger of a syringe. See, e.g., U.S. Pat. No. 5,057,078. 
         [0016]    There are other applications where it is desired to have an ability to control motion of one or more components and the direction of such motion. Some additional applications involve controlling the motion of a fluid (e.g., to dispense, inject, or aspirate a fluid). Other applications involve controlling the position of one or more solid items. 
         [0017]    Many conventional designs can limit or impede a user from dispensing and aspirating syringes, particularly large sized ones with one hand when one hand operation is desired. Therefore, in light of these challenges, it is desired to have a compact and lightweight device that can provide easy dispensing and aspirating modes when used with a syringe, the ability to switch between the two modes and do all this with one hand if desired without requiring outside assistance or requiring setting the syringe down at any point. It is also desirable that the device be able to provide mechanical advantage so that the user-applied force can be leveraged for very high dispensing or aspiration forces. It also is desired that the device be MRI safe and compatible, since therapeutic and diagnostic procedures using syringes may be conducted under Magnetic Resonance Imaging (MRI). 
       SUMMARY 
       [0018]    The present invention provides actuation mechanisms that incorporate a transmission assembly that allows the mechanisms to cause actuation in a plurality of transmission modes (e.g, at least one forward transmission mode and at least one reverse transmission mode). The mechanisms preferably are trigger-actuated by hand (i.e., manually) to cause movement of a workpiece in a desired direction. Desired directions can be linear or nonlinear. The same hand used for trigger action can also be used to change transmission modes in many modes of practice, even while using substantially the same grip used for trigger actuation. In other instances, actuation can be automated rather than manual. The transmission assembly is compact, elegantly simple in design, easy to manufacture and assemble, and easy to use (even with one hand if desired) to switch between transmission modes on demand. The actuation mechanism is useful in any application in which it is desired to move a workpiece, which can be a solid, liquid, or gas, in multiple directions, e.g., forward and reverse, gripping and releasing, etc. Exemplary uses include actuating syringes, actuating caulk cartridges, actuating mechanical clamps, actuating vacuum gripping devices, actuating furniture componentry to change the configuration of furniture (e.g., raising and lowering the height of a chair seat or changing the angle of a desk top), actuating toy water guns, actuating spray containers, and the like. 
         [0019]    For example, the present invention provides systems and methods in which a syringe actuation device is coupled to and then used with a syringe to aspirate or dispense, on demand, the syringe. In preferred modes, trigger actuation is used to operate the syringe. Using the transmission assembly to select the desired transmission mode, the same trigger action can be used both to dispense and aspirate syringe contents as desired. Advantageously, actuation and switching between dispensing and aspiration modes can be accomplished with one hand. In illustrative embodiments, the actuation devices of the present invention include a configurable transmission assembly that couples an actuation force to different motions of a syringe carriage. In one mode, the carriage actuates the syringe in a dispensing mode in which syringe contents are dispensed. In another mode, the carriage actuates the syringe in an aspiration mode to draw material into the syringe. 
         [0020]    The present invention offers numerous advantages over other syringe dispensing and aspiration devices. In many embodiments, the devices are made of materials that allow the devices to be used in diverse environments including with Magnetic Resonance Imaging equipment. For example, representative embodiments can be made of non ferrous materials including plastics that are suitable for use in procedures that also involve use of Magnetic Resonance Imaging equipment, which creates a strong magnetic field around the patient. 
         [0021]    Preferred embodiments allow, if desired, single-handed aspiration and dispensing of even very large syringes that otherwise would have a large plunger stroke or require much actuation force. Furthermore, an ergonomically designed and placed clutch of a configurable transmission system allows the same hand performing the aspiration and dispensing to also switch between these two modes without requiring a second hand or having to set the device down. Other preferred embodiments may remove or add features of the clutch and configurable transmission system to create aspiration only versions of the invention, or dispensing only versions, or ones with a neutral position (neither aspirating or dispensing). 
         [0022]    In one aspect, the present invention relates to a syringe actuation system, comprising:
       a) a syringe comprising a plunger and a syringe body having a first open end and a second open end, wherein the plunger fits into the first open end of the syringe body and is slideable to be moved into the syringe body toward the second open end and is slideable to be pulled from the syringe body away from the second open end; and   b) a syringe holding and actuation device
           i. a first portion that holds the plunger;   ii. a second portion that holds the syringe body, wherein the first and second portions are moveable relative to each other such that the plunger can be moved into and pulled from the syringe body;   iii. an actuation mechanism coupled to at least one of the first and second portions, wherein actuation of the mechanism causes relative motion between the first and second portions; and   iv. a transmission coupled to at least one of the first and second portions and to the actuation mechanism, said transmission comprising:
               1. a first transmission mode that causes relative movement of the first and second portions in a manner effective to cause the plunger to be moved into the syringe body when the actuation mechanism is actuated;   2. a second transmission mode that causes relative movement of the first and second portions to cause the plunger to be pulled from the syringe body when the actuation mechanism is actuated; and   3. a clutch system comprising a first configuration that causes the transmission to be in the first transmission mode and a second configuration that causes the transmission to be in the second transmission mode, wherein the clutch system comprises a rotatable shaft having an axis of rotation, wherein rotation of the shaft causes relative movement of the first and second portions in the first and second transmission modes, and wherein the shaft is shiftable along the axis of shaft rotation in a manner such that shifting the shaft along the axis of shaft rotation shifts the transmission between the first and second transmission modes on demand.   
               
               
 
         [0032]    In another aspect, the present invention relates to a syringe holding and actuation device for actuation of a syringe comprising a syringe body and a plunger, said device comprising:
       a) a first portion that holds the plunger;   b) a second portion that holds the syringe body, wherein the first and second portions are moveable relative to each other such that the plunger can be moved into and pulled from the syringe body;   c) an actuation mechanism coupled to at least one of the first and second portions, wherein actuation of the mechanism causes relative motion between the first and second portions; and   d) a transmission coupled to at least one of the first and second portions and to the actuation mechanism, said transmission comprising:
           i. a first transmission mode that causes relative movement of the first and second portions in a manner effective to cause the plunger to be moved into the syringe body when the actuation mechanism is actuated;   ii. a second transmission mode that causes relative movement of the first and second portions to cause the plunger to be pulled from the syringe body when the actuation mechanism is actuated; and   iii. a clutch system comprising a first configuration that causes the transmission to be in the first transmission mode and a second configuration that causes the transmission to be in the second transmission mode, wherein the clutch system comprises a rotatable shaft having an axis of rotation, wherein rotation of the shaft causes relative movement of the first and second portions in the first and second transmission modes, and wherein the shaft is shiftable along the axis of shaft rotation in a manner such that shifting the shaft along the axis of shaft rotation shifts the transmission between the first and second transmission modes on demand.   
               
 
         [0040]    In another aspect, the present invention relates to a method of actuating a syringe, comprising the steps of:
       a) providing a syringe actuation device according to claim  2 ;   b) loading a syringe into the device;   c) selecting a mode of actuation selected from dispensing and aspiration;   d) causing the actuation device to be in the desired mode of actuation; and   e) actuating the device to cause corresponding actuation of the syringe.       
 
         [0046]    In another aspect, the present invention relates to a syringe holding and actuation device for actuation of a syringe comprising a syringe body and a plunger, said device comprising:
       a) a first portion comprising (i) a slideable carriage that holds the plunger and (ii) gear teeth provided along at least a portion of the slideable carriage such that rotational motion applied to said gear teeth causes generally linear translation of the carriage back and forth corresponding to the direction of the applied rotational motion;   b) a second portion that holds the syringe body, wherein the carriage is slideably attached to the second portion such that the carriage is linearly translatable relative to the second portion such that the plunger held by the carriage can be moved into and pulled from the syringe body held by the second portion as the carriage translates;   c) an actuation mechanism coupled to at least one of the first and second portions, wherein actuation of the mechanism causes linear translation of the carriage relative to the second portion; and   d) a transmission mounted in the second portion and coupled to the translatable carriage, said transmission comprising:
           i. a rotatably driven gear coupled to the gear teeth of the carriage, said rotatably driven gear being driveable in first and second rotational directions to cause corresponding linear translation of the carriage in first and second linear directions relative to the second portion;   ii. a first selectively driven gear rotationally coupled to the rotatably driven gear in a manner effective to cause rotation of the rotatably driven gear in the first rotational direction when the first selectively driven gear is selectively driven;   iii. a second selectively driven gear rotationally coupled to the rotatably driven gear in a manner effective to cause rotation of the rotatably driven gear in the second rotational direction when the second selectively driven gear is selectively driven;   iv. a clutch system comprising a first configuration that causes the transmission to be in a first transmission mode that selectively drives the first selectively driven gear and a second configuration that causes the transmission to be in a second transmission mode that selectively drives the second selectively driven gear, wherein the clutch system comprises a rotatable shaft having an axis of rotation, wherein the rotatable shaft is rotatably driven by actuation of the actuation mechanism, wherein rotation of the shaft rotatably drives one of the first and second selectively driven gears on demand, and wherein the shaft is shiftable along the axis of shaft rotation in a manner such that shifting the shaft along the axis of shaft rotation shifts the transmission between the first and second transmission modes on demand.   
               
 
         [0055]    In another aspect, the present invention relates to an actuation device to control motion of a workpiece, comprising:
       a) a moveable component coupled to the workpiece;   b) a transmission coupled to the moveable component, said transmission comprising:
           i. a first transmission mode that causes the moveable component to be actuated in a first manner when the actuation device is actuated;   ii. a second transmission mode that causes the moveable component to be actuated in a second manner when the actuation device is actuated; and   iii. a clutch system comprising a first configuration that causes the transmission to be in the first transmission mode and a second configuration that causes the transmission to be in the second transmission mode, wherein the clutch system comprises a rotatable shaft having an axis of rotation, wherein rotation of the shaft causes the transmission to actuate the moveable component, and wherein the rotatable shaft is shiftable along the axis of shaft rotation in a manner such that shifting the shaft along the axis of shaft rotation shifts the transmission into the first or second transmission modes on demand.   
               
 
         [0061]    In another aspect, the present invention relates to an actuation device to control motion of a workpiece, comprising:
       a) a moveable component coupled to the workpiece;   b) a transmission coupled to the moveable component, said transmission comprising:
           i. a rotatably driven gear coupled to the moveable component, said rotatably driven gear being driveable in first and second rotational directions to cause corresponding first and second motions of the moveable component;   ii. a first selectively driven gear rotationally coupled to the rotatably driven gear in a manner effective to cause rotation of the rotatably driven gear in a first rotational direction when the first selectively driven gear is selectively driven;   iii. a second selectively driven gear rotationally coupled to the rotatably driven gear in a manner effective to cause rotation of the rotatably driven gear in a second rotational direction; and   iv. a clutch system comprising a first configuration that causes the transmission to be in a first transmission mode that selectively drives the first selectively driven gear and a second configuration that causes the transmission to be in a second transmission mode that selectively drives the second selectively driven gear, wherein the clutch system comprises a rotatable shaft having an axis of rotation, wherein the rotatable shaft is rotatably driven and wherein rotation of the shaft rotatably drives one of the first and second selectively driven gears on demand, and wherein the shaft is shiftable along the axis of shaft rotation in a manner such that shifting the shaft along the axis of shaft rotation shifts the transmission between the first and second transmission modes on demand.   
               
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0068]    The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate several aspects of the present invention and together with description of the exemplary embodiment serve to explain the principles of the invention. Additionally, foregoing and other objects, features and advantage of the invention will be apparent from the following description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. A brief description of the drawing is as follows: 
           [0069]      FIG. 1  (prior art) is a perspective view of a typical syringe with the plunger separated from the syringe body. 
           [0070]      FIG. 2  (prior art) is a perspective view of the syringe of  FIG. 1  with the plunger assembled in the syringe body. 
           [0071]      FIG. 3  (prior art) is a perspective view of the syringe of  FIG. 1  with a user hand gripping the syringe to dispense or inject. 
           [0072]      FIG. 4  (prior art) is a perspective view of the syringe of  FIG. 1  with a user hand gripping the syringe to aspirate. 
           [0073]      FIG. 5  is a perspective view of a preferred embodiment of an injection and aspiration device according to the present invention. 
           [0074]      FIG. 6  is a perspective view of the embodiment of  FIG. 5  coupled to a syringe. 
           [0075]      FIG. 7  is a perspective closeup view of select components of the transmission assembly within the device of  FIG. 5 . 
           [0076]      FIG. 8  is a bottom view of select components of  FIG. 7 . 
           [0077]      FIG. 9  is the same view as  FIG. 8  except with the components inside one of the gears shown exploded from the main assembly. 
           [0078]      FIG. 10  is a perspective view of select transmission components from  FIG. 7  with the ratchet and pawl components shown exploded from the main assembly. 
           [0079]      FIG. 11  is a perspective view of the components from  FIG. 10  with a trigger attached. 
           [0080]      FIG. 12  is a perspective view of select components of the clutch mechanism of the device of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0081]    Exemplary embodiments of the present invention are described in the following with reference to the drawings. It should be understood that such embodiments are by way of example only and merely illustrative of the many possible embodiments which can represent applications of the principles of the present invention. Various changes and modifications obvious to one skilled in the art to which the present invention pertains are deemed to be within the spirit, scope and contemplation of the present invention as further defined in the appended claims. The exemplary embodiments of the present invention described herein are not intended to be exhaustive or to limit the present invention to the precise forms disclosed in the following detailed description. Rather the exemplary embodiments described herein are chosen and described so those skilled in the art can appreciate and understand the principles and practices of the present invention. 
         [0082]    Referring to  FIGS. 1 and 2 , a typical syringe  100  is shown disassembled in  FIG. 1  and assembled in  FIG. 2 . Syringe  100  is a type of syringe that is easily used in many modes of practice of the present invention. One illustrative system of the present invention that incorporates these types of syringes is described further below. The syringe  100  includes a plunger  101  and a syringe body  102 . The end of the plunger often is made of a material and of a diameter that allow end  103  and optionally other portion(s) of plunger  101  to seal against the inner wall of the main part of the syringe body  102  along which the plunger  101  moves. Syringe body  102  defines a reservoir  119  for holding material(s) (not shown) to be dispensed from or aspirated into body  102 . The open tip  104  of the syringe body  102  is opposite the end  109  through which the plunger  101  is inserted. Tip  104  has an opening  112  through which the fluid passes into and out of the syringe body  102  as the plunger  101  is moved accordingly. This opening  112  is typically smaller than the main portion or bore of the syringe body  102  along which the plunger  101  including  103  travels so that tip  104  can be connected to other components like needles, tubing, and catheters, for example. The exterior of the syringe body  102  typically has a flange  105  to facilitate a user or equipment to interface with the syringe body. In  FIG. 1 , flange  105  is shown with two extensions or tabs  106  and  107 . The plunger  101  typically also has a plunger flange  108  that is used to facilitate a user or equipment to interface with the plunger  101 . 
         [0083]    The process of injecting or dispensing material that may be within reservoir  119  of the syringe body  102  is accomplished by moving the plunger  101  towards the tip  104  of syringe body  102  as indicated by arrow  110  in  FIG. 2 . For purposes of the present invention, this first mode of actuation of plunger  101  is referred to as the forward or dispensing mode of actuation. The process of aspirating material into the syringe body  102  is accomplished by moving the plunger  101  away from the tip  104  of the syringe body  102  as indicated by arrow  111  in  FIG. 2 . For purposes of the present invention, this second mode of actuation of plunger  101  is referred to as the reverse or aspirating mode of actuation. Using syringe  100  by itself, injection and aspiration can be done manually by a user with a single hand if the syringe is not too large. Manual actuation, particularly one-handed actuation, is more difficult with larger syringes. In contrast, manual actuation is substantially easier using principles of the present invention, even with larger syringes. Moreover, the systems of the present invention described below also allow a user to easily select either the forward or reverse actuation modes on demand. In preferred modes of practice, the same hand that actuates the system also can be used to select the desired actuation mode. 
         [0084]      FIG. 3  illustrates one manner in which a user would hold a syringe  200  for dispensing with a single hand  201  without assistance from an actuation accessory of the present invention. In this example, two fingers  202  and  203  are placed on the tabs  204  and  205  of the syringe body flange  206 , and the thumb  207  on the plunger flange  208 . When the syringe  200  gets larger in length and cross section size, such as with a 60 mL size syringe, the ability to squeeze a fully filled syringe with a single hand becomes very difficult. One factor contributing to this difficulty is the increasing distance  209  that the fingers  202  and  203  must reach. As this distance  209  approaches the maximum reach of the hand  201 , the squeeze force a user can apply decreases. For users with small hands, the distance  209  may be so large that a user may not even be able to reach between the plunger flange  206  and the syringe body flange  208  with one hand to start dispensing. 
         [0085]      FIG. 4  illustrates one manner in which a user would hold a syringe  300  for aspirating with a single hand  301  without assistance from an actuation accessory of the present invention. In this example, two fingers  302  and  303  are placed on the plunger flange  304 , and the thumb  305  pushes on one of the tabs  306  of the syringe body flange  307 . If the syringe  300  were to be larger in length and cross section size, such as with a 60 mL size syringe, the ability to fully extend the plunger  308  with a single hand becomes very difficult due to the increasing distance  309  that the fingers  302  and  303  must reach. As this distance  309  approaches the maximum reach of the hand  301 , the pushing force a user can apply decreases. But even more significant is that the reach is largely limited by the reach of the thumb finger  305  relative to fingers  302  and  303 . In some cases, a user may not even be able to fully extend the plunger  308  to completely fill the syringe  300  using only one hand. 
         [0086]      FIGS. 3 and 4  illustrate single hand positions holding a relatively large syringe for dispensing and aspiration, respectively. It can be seen that these two hand positions are very different. To switch between the two holds is awkward and cumbersome without setting the syringe down between the holds or without assistance from a second hand. There are other methods in which the syringe can be held with one hand that are not shown. However, in any position, the hand must span both the syringe flange as well as the plunger flange, and, therefore, the stroke is limited by the size of the user&#39;s hand. 
         [0087]    Referring now to  FIGS. 5 and 6  a preferred embodiment of a system  50  of the present invention that includes device  500  and syringe  550  coupled to device  500 . System  50  can be used to both dispense and aspirate syringe contents (not shown). System  50  also easily switches between these two modes, advantageously with the same hand holding and actuating the device  500  if desired.  FIG. 5  shows just the device  500  and  FIG. 6  shows the device  500  with a typical syringe  550  mounted to it. 
         [0088]    The device  500  has a main housing or chassis  513  made of two halves  501  and  520 , each with a holder  502  and  523  respectively, which interface with the syringe body flange  552  of the syringe body  551 . The two housing halves  501  and  520  are held together in this example with fasteners  519  and  522 . Any number of fasteners could be used and alternative fastening methods could also be used such as snaps or adhesives for bonding the two halves. Housing half  501  also has guide rail  504  incorporated into it, and housing half  520  has guide rail  503  incorporated into it. 
         [0089]    The carriage  505  is a component with a tooth pattern  509  incorporated into the bottom side along at least a portion of the length of carriage  505 . Each side of carriage  505  has a channel (only one channel  506  can be seen in these views) that is along its entire length in this embodiment for purposes of illustration. The rear of the carriage  505  has a protruding structure  521  into which a retention feature or holder  507  is incorporated. The other end (not seen in the figures because the view is obstructed by the holder  502 ) does not have any protruding features in this embodiment, but may include such features in other embodiments. The plunger  553  of the syringe  550  has plunger flange  554 , which interfaces with and is held by the carriage holder  507 . The side channels (only  506  is seen in these views) of carriage  505  slidingly interface with mating rails  503  and  504 . The carriage  505  also has a tooth pattern  509  to which the tooth pattern of the main drive gear  701  interfaces. 
         [0090]    Referring now also to  FIGS. 7 through 12 , the device  500  has transmission assembly  700  which includes clutch system  531  and gear system  541 . Clutch system  531  includes clutch  511 , trigger  510 , pawl holder plate  840 , threaded ball plunger  831 , pawls  801  and  802 , and ratchet gear  800 , which has a D-shape shaft opening  803 . The clutch  511  has grooves  832  and  833 , a shaft  532 , and a clutch plate  705  that has holes  706 . Pawl  801  has a shaft  804  and flex arm  805 . Pawl  802  has a shaft  810  and flex arm  806 . Gear system  541  includes gears  701 ,  702 ,  703 , and  704 , gear holder plate  841 , and post plate  714  and spring  715  that comprise post assembly  712  for gear  702 . 
         [0091]    Depending upon which operation mode is selected, transmission assembly  700  can drive carriage  505  forward (first or dispense mode) or in reverse (second or aspiration mode). Forward mode presses plunger  553  into syringe body  551 . This creates pressure that dispenses syringe contents. Reverse mode pulls plunger  553  out of syringe body  551 . This creates aspiration that pulls contents into syringe  550  from an external source. Transmission assembly  700  includes clutch features to easily shift between forward and reverse modes on demand. 
         [0092]    The transmission assembly  700  transmits the actuation force imparted by the user on the trigger  510  to the carriage  505 . The transmission assembly  700  can change the rotational direction of the main drive gear  701  when the clutch  511  is shifted from one side to the other along its axis as indicated by the arrow  512 . This unique transmission assembly  700  allows a user to move the plunger  553  of the syringe  550  in either direction (aspiration or dispensing) using the same trigger actuation of the trigger  510  towards the grip  513  of the chassis  501 . The clutch  511  is designed and positioned in a way that a user can easily move it from side to side. Advantageously, this can be accomplished using a finger and/or thumb of the same hand that is holding and pulling the trigger  510  if desired. A torsion compression type spring  860  is incorporated between the inside of the trigger  510  and the housing  513  to keep the trigger  510  biased open (starting position) and away from the housing  513 . 
         [0093]    Referring to  FIG. 7 , the transmission assembly  700  is shown in greater detail with just a portion of the housing half  520  shown. The teeth of the main gear  701  engage with the teeth  509  of the carriage  505 . There are two gears  702  and  703  that directly engage with the main gear  701 . Gear  703  also engages directly with gear  704 . Clutch  511  causes one of gears  702  and  704  to be selectively engaged and driven by trigger actuation at one time. The clutch  511  has a clutch plate  705  with a number of holes  706  that are used to selectively engage the clutch  511  with one of gears  702  and  704 . The shaft of the clutch  511  passes through the bore of gears  702  and  704 , and through ratchet  800  (also called ratchet gear  800 ). As will be shown later, the bore of ratchet  800  has a key feature to rotationally lock it to the shaft of the clutch  511 . The ratchet  800  engages with pawl  801  that is mounted to trigger  510  and pawl  802  that is mounted to housing  501 . 
         [0094]    Now referring also to  FIG. 8 , a bottom view of select components of the transmission assembly  700  is shown further illustrating the gears  702  and  703  that directly engage with the main gear  701 . The gears  702  and  704  that also directly engage with the clutch  511  are shown. In this view, a plurality of posts  710  that extend from gear  702  and a plurality of posts  711  that extend from gear  704  are visible. These posts  710  and  711  selectively pass into the holes of the clutch plate  705  to rotationally lock the clutch plate  705  to the corresponding gear being engaged at the time. In  FIGS. 7 and 8  the clutch  511  is shown engaged with gear  704 , and posts  711  help secure clutch plate  705  to gear  704 . 
         [0095]      FIG. 9  shows the same components as in  FIG. 8  but with an exploded view of the post assembly portion  712  for gear  702 . The posts  710  extend from a common plate  714  through which the shaft of the clutch  511  also passes. A spring  715 , shown as a wavy spring, presses against the post plate  714  on one side and is held against housing  501  (not shown in this FIG.) to create a force to bias plate  714  toward clutch plate  705 . The spring  715  also has the shaft of the clutch  511  pass through it. The spring  715  allows the posts  710  to be depressed by the clutch plate  705  if holes  706  do not happen to align with the posts  710  at the time the clutch  511  initially is shifted to engage with gear  702 . A similar type of assembly as post assembly portion  712  exists for the other gear  704 , so that clutch  511  can engage gear  704  to rotate gear  701 , and hence drive carriage  505 , in the other direction. 
         [0096]    From these descriptions of the gear and clutch components of transmission assembly  700  illustrated in  FIGS. 7 through 9 , it can now be seen how, as the clutch  511  selectively engages gears of transmission assembly  700 , trigger actuation can move the carriage  505  forward or backwards, which correspond to dispensing and aspirating the syringe, respectively. The forward or reverse mode is selected depending upon whether clutch  511  is engaged with gear  702  or  704 . 
         [0097]    Now referring to  FIGS. 10 and 11 , ratchet features are shown in more detail that describe how the ratchet  800  can be controlled using pawls  801  and  802  to only rotate ratchet  800  in one (forward) direction  809 . For purposes of illustration, the ratchet  800  and pawls  801  and  802  are removed from the shaft of the clutch  511  in  FIG. 10  to show how the D-shape bore  803  of the ratchet  800  interlocks with the mating D-shape portion  807  of the clutch  511 . As a result of this interlock, any rotation of the ratchet  800  will cause a rotation of the shaft  532  of the clutch  511 . The shaft  804  of pawl  801  engages with the trigger  510  and allows pawl  801  to pivot about the shaft  804 . Flexure  805  of pawl  801  is flexed against the inside of the trigger  510 . This creates a bias force that keeps the pawl  801  pressed against the ratchet  800  and yet allows pawl  801  to ride over the teeth of the rotating ratchet  800 . The orientation of pawl  801  to the ratchet  800  is such that, as the trigger  510  is squeezed or pulled towards the grip  513  ( FIGS. 5 and 6 ), the teeth of the pawl  801  interlock with the teeth of the ratchet  800  and cause the ratchet  800  to rotate in direction  809 . This in turn causes the clutch  511  to rotate also in forward direction  809 . When the trigger  510  is released, spring  860  shown in  FIGS. 5 &amp; 6  moves the trigger  510  back outward and it is during this motion that the pawl  801  rides over ratchet  800  teeth. In short, trigger  510  is operatively coupled to ratchet  800  via pawl  801  so that trigger actuation rotationally drives ratchet  800  forward in direction  809  and hence the shaft  532  of the clutch  511 . This motion will cause the carriage  505  to move either forward or backward depending on which gear,  702  or  704 , the clutch plate  705  selectively engages. The second pawl  802  prevents backward rotation (opposite  809 ) of ratchet  800 . 
         [0098]    Pawl  802  also has a shaft  810  that interfaces to the housing  513  shown in  FIGS. 5 and 6 , and allows pawl  802  to pivot about this shaft  810 . Flexure  806  of pawl  802  is flexed against the inside of the housing  501  and creates a bias force that biases the pawl  802  against the ratchet  800  to help prevent backwards rotation (opposite  809 ) of ratchet  800 , but yet allows pawl  802  to ride over the teeth of the rotating ratchet  800  to allow forward rotation in direction  809  of ratchet  800 . The orientation of pawl  802  to the ratchet  800  is such that as the trigger  510  is squeezed or pulled towards the grip  513  ( FIGS. 5 and 6 ), the teeth of the pawl  802  pass over the rotating ratchet  800 . When the trigger  510  is released, spring  860  shown in  FIGS. 5 and 6  push the trigger  510  back open, while the teeth of pawl  802  engage the ratchet  800  and prevent counter rotation (opposite  809 ) of the ratchet  800  and therefore motion of the transmission  700  and carriage  505 . The two pawls  801  and  802  therefore only allow the ratchet  800  to rotate in one direction indicated by arrow  809  in  FIG. 10  and help to prevent counter rotation. This is the main principle of these components and the design described herein is the preferred embodiment. Alternative embodiments are possible, and one example would be to make the pawls  801  and  802  completely rigid components and use a compression coil spring to provide the bias forces against the pawls. 
         [0099]    Referring now to  FIG. 12 , select components of the device  500  shown in  FIG. 1  are shown that show how the clutch  511  is held in the different positions. As has been described previously and shown in the figures in this preferred embodiment, the clutch  511  can move side to side so that its clutch plate  705  can selectively engage with gears  702  and  704 . To ensure that the clutch  511  maintains the engaged position and provides a tactile feedback to the user that the engagement has been achieved, the housing  520  has a threaded hole  830  into which a standard type of threaded ball plunger  831  is placed. The ball plunger  831  interfaces with the shaft of the clutch  511  and extends into groove  832  when the clutch  511  is moved to engage with gear  704 , and extends into groove  833  when the clutch  511  is moved in the other direction to engage with gear  702 . The holding force provided by the ball plunger  831  prevents the clutch  511  from being pushed back as it is shifted against one of the gears  702  or  704  when the holes  706  of clutch plate  705  do not happen to align with the respective posts  710  or  711 . When this happens, clutch plate  705  depresses the posts  710  or  711 , which compresses the respective spring, for example spring  715  for posts  710 , until the posts  710  or  711  align with the holes  706  of the clutch plate  705 . This allows the posts  710  or  711  to extend into the holes  706  to create selective engagement between the clutch  511  and the respective gear  702  or  704 . 
         [0100]    The preferred embodiment presented in  FIGS. 5 through 12  provides the features to allow a syringe to be dispensed and aspirated by moving a rotating clutch between two positions. The rotation of the shaft  532  of clutch  511  is always in one forward rotationally direction  809  in this illustrative embodiment. Shaft rotation occurs when a user pulls on trigger  510 . The forward rotational direction  809  of clutch  511  is controlled by two pawls,  801  and  802 , and ratchet gear  800 . In the dispensing mode, the clutch  511  is moved to engage gear  704  that meshes with a second gear  703 . Gear  703  in turn meshes with a final drive gear  701  that finally meshes with the teeth  509  of carriage  505 . These series of gears are necessary so that the single forward rotational direction  809  of clutch  511  moves the carriage  511  forward to dispense contents of a syringe. In the aspiration mode, the clutch  511  is moved to engage gear  702 , which meshes directly with the final drive gear  701  that again meshes with the teeth  509  of carriage  505 . In this way, the single forward rotational direction  809  of clutch  511  can also move the carriage  511  backwards to aspirate material into the syringe. The single forward rotational direction  809  of clutch  511  is created by having a pawl  801  attached to trigger  510 . This pawl  801  drives the rotation of ratchet gear  800  which is directly coupled to clutch  511 . When the user releases trigger  510 , the spring  860  pushes the trigger  510  back open to the starting trigger position for the user to squeeze the trigger  510  again. The second pawl  802  prevents the ratchet gear  800  and therefore the directly coupled clutch  511  from rotating in the backwards rotational direction (opposite direction  809 ) as the trigger  510  is pushed back to the starting trigger position. 
         [0101]    An alternative embodiment of a different configuration is one in which an additional groove is provided, e.g., placed between the two  832  and  833  that are used to engage the gears  702  and  704 . This additional groove would allow a neutral position where the clutch plate  705  does not engage either set of gears  702  or  704 . In another preferred embodiment, an aspiration-only configuration is created by removing gears  704  and  703 . In yet another preferred embodiment of a dispensing-only configuration, gear  702  is removed. In yet another preferred embodiment, the holder  502  and  523  can be detached from the housing halves  501  and  520 , and connected to its own carriage that is connected by additional gears to the main gear  701  so that it moves in a direction opposite the carriage  505 . 
         [0102]    Advantageously, all of the components described herein can be made of non-ferrous materials which would make them suitable for use with MRI. The gears and housing in particular can also be cost effectively mass produced with injection molded plastic. Additionally, the relative sizes of the gears can be modified to generate different amounts of mechanical advantage for the force transmitted to the syringe by the trigger independently for each direction. 
         [0103]    There are other applications where it is desired to have an ability to control motion of one or more components and the direction of such motion. Some additional applications involve controlling the motion of a fluid (e.g., to dispense, inject, or aspirate a fluid). Other applications involve controlling the position of one or more solid items. The present invention would be suitable to control actuation in multiple directions in a wide variety of such applications, including but not limited to the following exemplary uses. 
         [0104]    General barrel plunger devices are conceptually similar to a fluid syringe but instead are configured so that a plunger is coupled to a solid object instead of a fluid. The principles of the present invention can be used to control actuation of the barrel plunger in both forward and reverse directions. 
         [0105]    Some gripping devices control the movement of gases in order to grip and release items. For example, one device (known as a pooter device) allows small insects to be gently collected and held against an intake membrane such as a filter by steady intake of air through the membrane. The insect can be transferred to a container or other target by reversing operation and dispensing air or other gas through the membrane in the other direction. Vacuum gripping devices also are used in the microelectronic industry to hold workpieces. The principles of the present invention can be used to control actuation of pressurizing and aspirating components that cause the gas to provide gripping and releasing forces on demand. 
         [0106]    Manual positioning systems can be used to control the position of items. An example is to control the height position of a chair via positive manual actuation to raise, lower, twist, or otherwise modify the chair configuration. Conventionally, gravity often is used to create a downward motion and a mechanical force would be used for upward motion. This conventional system would be replaced by a mechanism of the present invention that allows a user to control and move the chair in both directions via mechanical actuation, preferably without needing to stand up to raise or lower the height of the chair. 
         [0107]    In another type of manual positioning system, one or more clamps are used to maintain the position of an object. Releasing the clamp allows the object to be re-positioned. A specific example includes the clamps that are used to position the legs of a camera tripod. The principles of the present invention can be used to control actuation of the clamps to both grip and release objects. 
         [0108]    The present invention can also be used in toy water guns to control pressure and dispensing mechanisms. For instance, a transmission of the present invention can be used to actuate one or more components in a manner effective to aspirate water into the barrel of a toy water gun. The transmission mode can then be switched to actuate one or more components in a manner effective to dispense the water as a jet. Alternatively, the transmission of the present invention can be used to actuate one or more components in a manner effective to pressurize at least one chamber that to dispense the water. In some embodiments this could replace a typical two-handed pump action and allow pressurizing and dispensing to be accomplished with one hand. 
         [0109]    The principles of the present invention also can be incorporated into other kinds of gripping tools such as clamps used to hold items together for gluing, welding, bolting, nailing, screwing, other fastening, or other treatment. Examples of these include clamps used in wood and metalworking. Other examples include golf shaft extractors that both grip a golf shaft and push against a club head to remove the head from the shaft. Transmissions of the present invention can be used to create the force that grips and releases the club and/or the force that pushes against the club head relative to the shaft. 
         [0110]    The present invention has now been described with reference to figures of an exemplary embodiment thereof. The entire disclosure of any patent or patent application identified herein is hereby incorporated by reference for all purposes. The foregoing disclosure has been provided for clarity of understanding by those skilled in the art of injection and aspiration devices. No unnecessary limitations should be taken from the foregoing disclosure. It will be apparent to those skilled in the art that changes can be made in the exemplary embodiment described herein without departing from the scope of the present invention. Thus, the scope of the present invention should not be limited to the exemplary structures and methods described herein, but only by the structures and methods described by the language of the claims and the equivalents of those claimed structures and methods.