Abstract:
Hand-held shellfish pliers, comprising a first handle ( 1 ), a second handle ( 2 ), first jaw ( 24 ) and second jaw ( 35 ), wherein said first jaw ( 24 ) is arranged on one of said handles ( 1, 2 ), and wherein there is arranged a pivot point (A) for interaction between the handles ( 1, 2 ), and wherein the jaws ( 24, 35 ) form a converging gap, presenting an opening (Dmax) in the diverging extension (E) of said gap, wherein there is a multiple lever structure where the force applied to the handles ( 1, 2 ) is geared via fulcrum points (A, B) in order to magnify said force.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to hand-held shellfish pliers, comprising a first handle, a second handle, first jaw and second jaw, wherein said first jaw is arranged on one of said handles and wherein there is arranged a pivot point for interaction between the handles, and wherein the jaws form a converging gap, presenting an opening in the diverging extension of said gap. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is known that the shells of crustaceans, such as lobster, crabs or clams, must be broken in order to access the meat inside. The shells are often quite hard, and the use of some kind of tool is therefore required. Since the opening of the shellfish generally takes place at the table during the meal, the tool should be handheld and easy to use. 
         [0003]    A handheld shellfish-opening tool is shown in U.S. Pat. No. 6,817,937B1, where an upper and a lower handle are connected at a pivot at the far end, and segments of the handles forming a serrated jaw area are present next to the pivot. The tool can be operated by gripping the other end of the handles and pressing them together, such that that part of the shellfish which is placed between the jaw segments of each handle is cracked. While pressing the handles together, the user generally applies as much force as is needed to crack the shell, and the force is propagated along the handles. Since the jaw segment is close to the part of the handles where the force is applied, however, the possible lever is short and the force must be great in order to break the shell. With so great a force it is difficult for the user to control the process, and often the result is that after the shell is broken, the applied force makes the meat, juice and fragments of the shell spray over the surrounding area and sometimes even the user. 
         [0004]    U.S. Pat. No. 6,019,673 shows a handheld crab cracker where a pair of handles are connected at a pivot, and the handles on the other side of the pivot form a pair of jaws for cracking the shell of shellfish. Here, the handles are bent so that the jaws cannot close completely, and thus the meat of the shellfish is kept intact after the shell itself is broken. It is still a problem, however, that shell fragments and the juices inside can spray over the surrounding area when the shell is cracked. Also, the force needed to crack the shells is large, since the lever used for transmitting the power to the jaws is short. 
         [0005]    A common problem with tools of this kind is that the eating of shellfish is a generally messy procedure, where the meat, juice and shell fragments of the shellfish are spread over a larger area, including the tool itself. The need for cleaning the tool after use is thus great, but when the different parts of the tool is not easily separable, as is the case for the tools mentioned above, the cleaning process can be cumbersome and unsatisfactory. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    The object of the invention is to provide hand-held shellfish pliers where there is a multiple lever structure where the force applied to the handles is geared via fulcrum points in order to magnify said force. Thereby, a maximum of effective force is achieved at the closing of the jaws, which facilitates the operation of the device and makes it possible to achieve a desired result without uncommon strength or technique being required from the user. 
         [0007]    Another aspect of the invention is to provide handheld shellfish pliers which comprise at least two, preferably three, parts which can be demounted. Thereby, the pliers can easily be handled and kept clean. 
         [0008]    Another aspect of the invention is to provide handheld shellfish pliers which in one of the handles and/or the jaw section comprise a resilient structure which is arranged to urge the jaws into their open state. Thereby, the closing movement of the jaws can be controlled to a greater extent and allows for more control over the process of cracking the shell of the shellfish. 
         [0009]    Another aspect of the invention is to provide handheld shellfish pliers where a portion of the jaw section protrudes in the direction away from the jaws and is arranged to interact with at least a part of one of the handles. Thereby, the resilient structure mentioned above can be coupled between the jaw section and the handle, where the resiliency resides mainly in a portion of the jaw section or in one of the handles. 
         [0010]    Another aspect of the invention is to provide handheld shellfish pliers which are arranged to be separable into at least two parts, preferably without any need of tools. Thereby, demounting the device becomes increasingly simple and can be performed by the user without the need for any special skill or excessive training 
         [0011]    Another aspect of the invention is to provide handheld shellfish pliers where the jaw structure is attached to the second handle at a fixed jaw structure pivot point. Thereby, the jaw section can pivot around this point, thus focusing the movement entirely to the area where it is required, i.e. the closing of the jaws, without risking that the whole jaw section slides when pressure is applied. 
         [0012]    Another aspect of the invention is to provide handheld shellfish pliers where the width of the first jaw is larger than the width of the second jaw. Thereby, the wider upper jaw prevents the meats or fluids of the shellfish from spraying upwards during use, which would risk staining the surrounding area or even the user. Instead, any spray can be focussed downwards towards the table or the plate. 
         [0013]    Another aspect of the invention is to provide handheld shellfish pliers where the first handle is arranged with a slit and the second handle is also arranged with a slit, both of these in turn arranged to allow a jaw section activation part to extend therethrough. Thereby, the jaw section can be mounted through the handles and kept in place by them, which allows for convenient operation of the device without the need for further parts for locking or controlling the jaw section. 
         [0014]    Another aspect of the invention is to provide handheld shellfish pliers where the first handle and the jaw section are interconnected by means of at least one protrusion on one of said first handle or second handle and jaw section interacting with a cavity in the other. Thereby, the pieces of the shellfish pliers are fixed together in the desired way. Preferably, said cavity could be a through hole. 
         [0015]    Another aspect of the invention is to provide handheld shellfish pliers where more than one cavity are arranged for interconnecting the first handle with the jaw section, thus allowing for varying the length of the lever in order to vary the magnitude of the force needed to move the jaws. Thereby, a “higher gear” is made available for breaking open unusually hard shellfish shells, where the pliers can be mounted in an alternative way to couple more force from the handles to closing jaws. 
         [0016]    Another aspect of the invention is to provide a method for operating handheld shellfish pliers where the changes ΔT, ΔD of the distance T between the gripping parts of the handles and the distance D between the jaws are such that the quotient ΔT/ΔD during use of the pliers is larger than 1. Thereby, the force applied to the handles is magnified during operation and results in a smaller movement in the closing of the jaws than at the closing of the handles, which means that the closing force thanks to the lever construction is larger at the jaws than at the handles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Other aspects, uses and advantages of this invention will be apparent from the reading of this description which proceeds with reference to the accompanying drawings forming part thereof and wherein: 
           [0018]      FIG. 1  shows a perspective view of a preferred embodiment of the invention, 
           [0019]      FIG. 2  shows a perspective view of the separate parts of the preferred embodiment of the invention, 
           [0020]      FIG. 3  shows a side view of the preferred embodiment of the invention, and 
           [0021]      FIG. 4  shows the preferred embodiment of the invention during use, 
           [0022]      FIG. 5  shows a front view of the preferred embodiment of the invention, 
           [0023]      FIG. 6  shows a second embodiment of the invention, 
           [0024]      FIG. 7  shows the embodiment of  FIG. 6  during use, and 
           [0025]      FIG. 8  shows a third embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    With reference to  FIG. 1  and  FIG. 2 , the construction and mounting of the invention will now be described. A first handle  1 , a second handle  2  and a jaw section  3  are joined to form handheld shellfish pliers. In order to put the pieces together, the jaw section activation part  36  is put through the jaw opening  21  of the second handle  2  and the slit  11  of the first handle, and the lock is achieved by the notch  32  being placed in the corresponding incision, the fixed jaw structure pivot point  22 , of the second handle  2 , and the first end portion  33  and second end portion  34  being fixed into the cavities  12  in the first handle  1  and  23  of the second handle  2 , respectively. 
         [0027]      FIG. 3  shows the shellfish pliers fully assembled. The handles  1 ,  2  are arranged to be gripped at their gripping parts  17 ,  26 , and the jaws are formed by the upper jaw  24  of the lower handle  2  and the lower jaw  35  of the jaw section  3 . The handles  1 ,  2  are held in position by the jaw section activation part, at whose first end portion  33  a fixed pivot point B is achieved by the insertion of the end portion  33  into the cavity  12 , and by the resilient structure  31  at whose end the second end portion  34  is inserted into the cavity  23 . The front part  14  of the first handle is placed against the front part of the second handle  2  on top of the frontmost part of the upper jaws  24 , and the contact between these areas of the handles ends in the active surface  13 A of the edge  13  of the upper handle, where a non-fixed pivot point A is formed. A non-fixed pivot point is a pivot point where the parts of the shellfish pliers can slide or roll with respect to each other. 
         [0028]    Between the jaws  24 ,  35 , a gap with the opening D max  is formed. A direction along the extension E of the gap can be defined and is indicated by the arrow in  FIG. 1 . 
         [0029]    The jaw section  3  with the jaw  35  and an upper structure  37  is made to be stiff, which is beneficial for the operation of the shellfish pliers and facilitates the use of a multiple lever structure in the pliers. 
         [0030]    Thanks to the rigidity and form of the pieces of the invention, a tension is achieved in the resilient structure  31  and the jaw section activation part  36  between the end point  33 , which is fastened in the upper handle, and the end point  34 , which is fastened in the lower handle. This tension keeps the device together and also plays an beneficial part in the operation of the device, which will be described in detail below. 
         [0031]    The pieces of the shellfish pliers are in this preferred embodiment made of a stainless steel which is easy to clean and performs the operation of the invention in a reliable manner. The steel is also a durable material and can withstand the effects of the forces needed to break different kinds of shells where some may be harder than others. The handles have a thickness t 1  and t 2 , indicated in  FIG. 2 , of 2,0 mm-3,0 mm, preferably 2,5 mm, and the jaw section has a thickness t 3  of 3,0-4,0 mm, preferably 3,6 mm. The length L 1  of the forward part  14  of the first handle  1  is about 35 mm, and the length L 2  of the rest of the first handle  1  is about 120 mm. The length L 3  of the second handle  2  is about 175 mm, and on the jaw section  3 , the length L 4  of the lower jaw  35  is about 90 mm and the length L 5  of the upper part, with the jaw section activation part  36  and the resilient structure  31 , is about 90 mm. 
         [0032]    It is beneficial that the device easily can be taken apart and put together again, to allow for easy and effective cleaning. Since shellfish leftovers are prone to turning bad after some time and can cause food poisoning, it is an especially beneficial feature that the device can be cleaned after each meal. 
         [0033]    Operation of the device is achieved by gripping the gripping parts  17 ,  26  of the handles  1  and  2  with one hand and pressing them together. The shape of the handles is designed to give the user an ergonomic grip and a balanced impression of the device. It is also advantageous that the second handle is wide enough to make it possible to put the pliers down into a standing position next to the plate at the meal, since this makes them easy to grip the next time the user wishes to use the device. 
         [0034]    When the handles  1  and  2  are thus pressed together, the non-fixedly arranged pivot point A of the active surface  13 A of the edge  13  acts as a fulcrum and the torque is transmitted towards the forward part  14  of the first handle  1 , where the end portion  33  of the jaw section  3  is fastened in the cavity  12 , resulting in the end portion  33  of the resilient structure  31  being forced upwards by the forward part  14 . The upper structure  37  of the jaw structure  3  now acts as a second lever, transmitting the applied force to the pivot point  22  of the second handle  2 . The result is that the jaw section  3  is forced upwards while the second handle  2  with the upper jaw  24  is held still, resulting in a closing of the jaws  24 ,  35 . Thanks to the lever system, the force applied by the user pressing the handles together is magnified, resulting in the shellfish being placed between the jaws  24 ,  35  being subjected to a maximum efficient force necessary for breaking the shell. The pivot point A of the active surface  13 A slides along the top of the second handle  2  to an end position A′, and the resilient structure  31  acts as a spring, trying to force the jaws back apart. Thus, when the shellfish shell begins to break and the user decreases the applied force, the jaws are moved apart by the construction itself rather than by the user, which allows for easy operation of the pliers and gets them ready for cracking the shellfish again, perhaps in a different place. 
         [0035]    Thus, the initial force which must be applied by the user is smaller than the force needed in other handheld devices used for cracking shellfish, which allows for greater control over the process and easier adjustment in the magnitude of the force by the user. When the shell begins to crack the user can, thanks to this level of control, lower the magnitude of the force applied and thus preserve the meat inside the shell. This also lowers the risk of unwanted damage to the meat of the shellfish or of spraying the contents of the shell across a larger area. 
         [0036]    The distance between the upper handle  1  and the lower handle  2  at the gripping parts  17 ,  26  is shown in  FIG. 3  and denoted by T max , and  FIG. 4  shows the now decreased distance between the same parts during operation of the pliers, denoted by T 1 . In a similar fashion, the maximum distance D max  and the distance during operation D 1  of the jaws  24 ,  35  are shown in  FIGS. 3 and 4 , respectively. The differences ΔT and ΔD are defined such that ΔT=T max −T 1  and ΔD=D max −D 1 . During operation of the device, the lever system and the coupling of the force applied to the handles act in such a way that the relation ΔT/ΔD&gt;1 always holds. 
         [0037]    It can be noted that the jaws  24 ,  35  are never completely closed during operation of the shellfish pliers, so that the relation D 1 &gt;0 always holds for the distance D 1  shown in  FIG. 4 . Thus the complete crushing of the shellfish and the meat inside is avoided. A situation might otherwise arise where the shell is broken and embedded in the meat in such a way that the use must separate every fragment of the shell from the meat before eating, or indeed entirely discard the meat as inedible due to its high content of shell fragments. 
         [0038]    If very hard shellfish are to be broken by the device, it is possible that more force is needed. The shellfish pliers can then be varied to allow for greater transmission of the force applied by the user. In putting the device together, the end portion  33  of the jaw section activation part  36  is placed into the cavity  15  rather than the cavity  12  of the first handle. The section of the forward part  14  acting in the transmission of the torque is thus shortened, making the force transmitted to the upper structure  37  even greater. Thus, the user can break even harder shellfish without needing to apply greater force at the handles, and can keep a greater level of control over the process. 
         [0039]    The slit  11  in the upper handle  1  is long enough to allow for a full closure of the jaws  24 ,  35  without the upper end of the slit  11  coming into contact with the resilient structure  31  which would otherwise hinder the operation of the pliers. 
         [0040]    The notch  32  which is put into the incision  22  acts as a pivot point in the operation of the device, keeping this end of the jaw section  3  firmly pressed against the back end of the incision  22  in the second handle  2 . Thus, the risk of deforming the device during use is lowered and a full transmission of the applied force is possible. 
         [0041]    In  FIG. 3 , a side view of this embodiment of the invention is shown with the pieces put together and ready for use. It can be seen that the jaw section  3  is placed in the standard way with the end  33  portion being inserted into the cavity  12  rather than the cavity  15 , since the edges  16 ,  25  of the first handle  1  match. If the cavity  15  had been used, the edge  16  would protrude, since this would mean that the whole of the first handle  1  had been moved to the left in  FIG. 3 . 
         [0042]    In this figure, the workings of the levers can be clearly seen. When a force is applied to the handle  1  at the right-hand side, non-fixedly arranged pivot point A of the edge  13  acts as a sliding fulcrum and slides towards the a position A′ which corresponds to the handles being fully closed, and the torque is transmitted along the left part  14  to the end portion  33  of the jaw section activation part  36 . The resulting force presses the end portion  33  upwards which in turn forces the lower jaw  35  upwards. The notch  32  is all the while firmly pressed against the incision  22 , keeping the inner end of the jaw section  3  in place and acting as a pivot for the resulting movement of the lower jaw  35 . Since the second handle  2  with its upper jaw  24  is thus pressed downwards by the end portion  34  of the resilient structure  31  as well as by the active surface  13 A of the edge  13  of the first handle, while the lower jaw  35  thanks to the resulting force upwards on the end portion  33  is pressed upwards, a closure of the jaws  24 ,  35  is achieved. 
         [0043]    During this operation, force is loaded into the resilient structure  31  and the gap  38  between the resilient structure  31  and the upper part  37  of the jaw section is widened slightly. When the force pressing the handles  1 ,  2  together is lessened or removed, the resilient structure  31  strives to return to its original position, thus forcing the jaws apart again. Thereby, the user can focus on the force needed for closing the jaws, rather than applying additional force for pulling the handles apart after a crack is achieved. 
         [0044]    In  FIG. 5 , a view of the open jaws of the device is shown from the jaw end, i.e. the left-hand side of  FIG. 3 . The upper jaws  24 A,  24 B of the second handle  2  are shown, as well as the lower jaw  35  of the jaw section  3 . The matching edges  16 ,  25  of the handles are also shown, as well as a glimpse of the resilient structure  31 . The width of the second handle  2  at the jaw is denoted by W, whereas the width of the lower jaw  35  of the jaw section  3  is denoted by V. It can be noted that W&gt;&gt;V, and the advantages of this relation will be described further below. 
         [0045]    The upper jaws  24 A and  24 B are tilted downwards for two important reasons. Firstly, the opening  21  which is formed between the jagged jaws  24 A and  24 B makes it possible to insert the jaw section activation part  36  of the jaw section  3  and thus put the pieces of the invention together in such a way that it can be used to open shellfish. Secondly, the jaws formed by the jagged upper jaws  24 A and  24 B and the lower jaw  35  have a triangular shape where the top is substantially wider than the bottom. This allows for a more controlled breaking of the shells with less risk of shattering the shellfish. If, however, the shell should break in a manner which causes a spray of shell fragments, shellfish meat or juices, the direction of this spray would be downwards, towards the platter of the user where less damage is caused than if the direction of the spray is random and could hit a wider area, including the user and other persons nearby. The width W of the lower handle  2  at the upper jaw  24 , which is substantially larger than the width V of the lower jaw  35  of the jaw section, further increases this advantage. 
         [0046]    The jaws  24 A,  24 B,  35  are jagged to keep the shellfish in place and to easier break the shell, since the force pressing the jaws together is focussed on the points of the jagged areas, which are also in contact with the shellfish. 
         [0047]    In  FIG. 6  a second embodiment of the invention is shown, and in  FIG. 7  this embodiment is shown during use of the shellfish pliers. Here, the resilient structure (formerly denoted by  31 ), is placed in the lower handle  2  and denoted by  27 . A backwards extending part  39  of the jaw section  3  is attached to the resilient structure  27  and the resilient structure  27  is secured by the indention  39 A shown in  FIG. 7 . When the handles  1 ,  2  are pressed together at the gripping parts  17 ,  26 , the pivot point A again acts as a sliding fulcrum, coupling the force applied to the jaw section activation part  36  which now acts as a second lever around the fulcrum at an incision  22 . The other end of this lever is the backwards extending part  39 , and the force is loaded into the resilient structure  27  while the lower jaw  35  is forced upwards, thus closing the jaws. When the pressure on the gripping parts  17 ,  26  of the handles is lessened, the resilient structure  27  strives towards its original position, thus opening the jaws again. 
         [0048]      FIG. 8  shows a third embodiment of the invention, where the jaw section  3  is attached to the second handle  2  at a pivot point  22 . A resilient structure  27  is located in the second handle  2  and a backwards extending part  39  engages the resilient structure  27  in such a way that a pressing together of the handles  1 ,  2  results in the lower jaw  35  being moved towards the lower jaw  24  and the backwards extending part  39  being moved downwards, thus loading the force into the resilient structure  27 . In this embodiment, the jaw section  3  can move relative to a pivot point  22  which is held immobile. 
         [0049]    The skilled person realises that the invention is not limited by the embodiment described above, but that many changes may be made within the scope defined by the appended claims. One realises for instance that resiliency could be achieved by a combination of the jaw section and one of the handles, rather than by one or the other. Different materials or materials of different dimensions could be used, and the shape of the handles could be varied to achieve different levels of ergonomy or stability. The resilient structure could also be longer or shorter and function in a different way in the shellfish pliers. It is even possible that the resilient structure could be separate piece of the construction, for instance a separate spring. The pivot point at the notch  32  could also be secured in a different way, or the parts of the shellfish pliers could be fastened together in such a way that separating them could not be done in an easy way. The pliers could be manufactured by any suitable method, for instance by punching or fine-blanking.