referring now in detail to the drawings where like reference numerals identify similar or like components throughout the several views , several different embodiments of the orthopedic braces of the present invention are described herein . the braces of the present invention are designed to be placed over the joint , e . g ., ankle or knee , in a flexible state , and maintained in such state . the brace remains in the flexible state until it receives a sufficient impact , at which point it transforms to a more rigid state to protect the joint . this is achieved by a transformation of the liquid within the brace to a solid state . various ways to cause the phase change from liquid to solid are disclosed herein by way of example , although other ways to achieve such phase transformation can be utilized . the braces include liquid contained in columns or compartments which provide flexibility to the brace so as not to inhibit the wearer &# 39 ; s mobility . when the brace is transformed to the hardened state , the columns form a rigid structure which thereby protects the joint . thus , automatically , the brace is transformed from a flexible brace in which the wearer &# 39 ; s motion and mobility are not affected so the wearer can participate uninhibited / unrestrained in activities , including athletic activities , to a rigid state which effectively “ locks ” the brace and limits movement / motion , thus protecting the joint . as can be appreciated , the present invention therefore provides a protective rigid brace on an automatic as needed basis . note that where there are multiple identical components in the particular figure , e . g ., sensors , compartments , only a few are labeled for clarity . turning now to a first embodiment of the knee brace of the present invention , and with reference to fig1 a - 2 , the knee brace is designated generally by reference numeral 10 and includes a plurality of columns or compartments 12 embedded in the wall of the brace 10 between an outer wall 14 and an inner wall 16 . contained within the columns 12 is a liquid 18 . the liquid is preferably a liquid metal . one type of metal that can be utilized is gallium which undergoes a phase transformation in response to temperature change . other metals are also contemplated . alternatively , the liquid can be a polymer or plastic which undergoes a phase transformation upon temperature change , provided the hardened state of such material is sufficient to protect the knee . as an alternative to temperature change to effect transformation from a liquid to a solid , chemical reactions are also contemplated such as by impact or as a result of the mixing of two liquids . these are discussed in more detail below . in the liquid state , the brace 10 remains flexible so as to not adversely affect mobility of the wearer . the columns 12 are shown extending substantially vertically , preferably extending the entire length , or substantially the entire length of the brace 10 . alternatively , the columns can extend in other orientations such as in a substantially diagonal orientation as in brace 40 of fig3 a - 3b or in a substantially horizontal orientation as in brace 60 of fig4 a - 4b . fig1 a illustrates the columns 12 filled with liquid in a liquid state to maintain the flexibility of the brace 10 , the columns sealed to keep the liquid within the individual compartments . likewise , fig3 a illustrates the sealed columns 42 filled with liquid 44 in a liquid state to maintain the flexibility of the brace 40 and fig4 a illustrates the sealed columns 62 filled with liquid 64 in a liquid state to maintain the flexibility of the brace 60 . as shown , preferably the columns extend along or across the entire region of the brace so that the entire knee and adjacent regions are protected . however , it is also contemplated that the columns can extend less than the entire length or provided only in certain regions of the brace so that only select regions of the brace are solidified . additionally , the columns 12 , 42 , and 62 are shown having a width 15 , 45 , and 65 , respectively . however , it is also contemplated that the columns can have a shorter width , thereby enabling more columns to be provided , or have a wider width , providing fewer columns . further , the columns need not be of uniform width , but can have varying width . such varying width can provide regions of differing hardness to accommodate various regions of the knee , if desired . fig5 a and 5b illustrate the type of impact that can cause the hardening of the liquid within the compartments . in fig5 a a rotational force of sufficient magnitude will trigger a response for solidifying the liquid within the columns 12 ( or columns 42 and 62 ). this rotation can be caused by an external impact or by internal impact on the brace such as by rotation or twisting of the wearer &# 39 ; s knee . in fig5 b a direct impact , e . g ., an external impact , of sufficient force will trigger hardening of the liquid within the columns 12 ( or columns 42 and 62 ). fig1 provides a flow chart to explain generally the function and use of the brace 10 . note the flow chart explains the use of the brace with liquid metal , it being understood as noted above , that other hardenable non - metal materials can be utilized . with reference to fig1 , brace 10 is initially in a soft state . if an external or internal force if applied , a sensor within the brace 10 , e . g ., sensors 18 of fig5 a and 5b , detects such force and measures the force . if the force does not exceed a preset threshold or predetermined value ( magnitude ), then the brace remains in its softer more flexible state and no signal is sent by the sensor to activate the metal . however , if the measured force exceeds a preset threshold / predetermined value , a signal is sent to a controller ( not shown ) position in or on the brace , to activate the liquid to transform it to a hardened state . activation of the liquid to transform it to a hardened state can occur in a variety of different ways as described herein . as shown in fig6 , one way to harden the liquid is to provide a cooling mechanism to cool the liquid . in this embodiment , sensors 38 , like sensors 18 of fig1 , are positioned internally of brace 30 , and located at various dispersed regions within the brace 30 to sense impact at the various regions . after detecting and measuring the force and determining it exceeds a predetermined or preset value , sensor 38 will send a signal to a controller ( not shown ). the controller in turn will send a signal to activate the cooling chambers 35 which surround each of the compartments 32 . such cooling of chambers 35 causes cooling of the liquid 34 in the liquid compartments 32 . upon cooling , the liquid 34 hardens , thereby forming rigid compartments and forming a protective somewhat cage - like structure . in the alternate embodiment of fig7 , brace 50 has a single cooling chamber 53 within the brace 50 . this single cooling chamber 53 functions to cool the liquid within the compartments 52 when activated in response to the force detection by the sensors 58 . the cooling chamber 53 can be provided within the wall of the brace 50 or alternatively formed internal of the internal wall of the brace 50 . alternatively , more than one cooling chamber can be provided to cool the brace 50 . brace 50 therefore differs from brace 30 in that in brace 30 , each liquid filled compartment 32 is partially or fully surrounded by a cooling chamber while in brace 50 , cooling of the chamber positioned within the brace 50 cools the entire brace which in turn cools the liquid within the compartments . fig1 - 11b illustrates another alternate way of transforming the liquid within the compartments of the brace . in this embodiment , sensors 78 , positioned within brace 70 , detect and measure the force of impact , or rotational force , and compare it to a predetermined or preset value . if it exceeds such value , a signal is sent to the pump within chamber 76 to actuate the pump for pumping liquid 75 from chamber 76 through tubing 77 into the liquid filled compartment 72 . a valve can be provided to seal the compartments 72 until liquid 75 is pumped therein . once the pumped liquid 77 mixes with the liquid 74 in the compartments 72 , a chemical reaction causes a hardening of the material within the compartments 72 and thus transforms the flexible brace 70 into a hardened cage - like structure . such activation of the liquid 74 within the compartments 72 is shown schematically in fig1 a and 11b , which illustrate one of the plurality of compartments 12 . if a sufficient force is detected by sensor 78 , a signal is sent to activate a pump ( not shown ) within the chamber 76 to pump liquid 75 from chamber 76 , through tubing 77 , and into the chamber 72 containing liquid 74 to thereby mix liquid 75 with liquid 74 . a single or multiple pumps and chambers can be provided . as an alternate to a pump to mix a second liquid with the liquid in the compartments , a rupturable wall or membrane could be provided . the brace in this embodiment would avoid the need for sensors and a controller . in this embodiment , brace 80 has a series of inner compartments 82 , each surrounded by an outer compartment 86 , and sharing a common wall . that is , the external wall 81 of the inner compartment 82 forms the internal wall of outer compartment 86 . wall 81 is made of a material which ruptures when a sufficient force is applied . in this manner , upon application of a sufficient force , the wall ( membrane ) 81 would break , enabling the liquid 84 of compartment 82 to mix with the liquid 85 contained in the outer compartment 86 . such mixing of the liquids causes a chemical reaction which results in a phase transformation to harden the liquid . in another embodiment , the liquid filled compartments are activated by an excessive bending or movement of the compartments which causes a chemical reaction as the movement ( energy ) provides a trigger for spontaneous transformation to a solid state . the liquid ferrous material in the compartments can also be activated for transformation into a solid state by electric charge , polarization or other inducement methods . the braces disclosed herein in some embodiments can be manually returned to the relaxed liquid state , i . e ., manually overriding the transformed solid state . note the control unit communicating with the sensors for controlling operation , i . e ., controlling activation of the liquid through polarization , electric charge , pumping fluid , etc ., can be software based and programmed to activate the liquid automatically in an as needed basis in response to signals received from the force detecting / measuring sensors . fig1 - 13b illustrate an alternate embodiment of the brace for use in supporting a person &# 39 ; s ankle . in this embodiment , ankle brace 90 is similar to the brace 10 of fig1 , except it is shaped to be fitted on a user &# 39 ; s ankle . that is , brace 90 has a plurality of liquid filled compartments 92 . the liquid 94 can be a metal or non - metal as described above with respect to the knee braces . the liquid can be transformed to a harder state in any of the ways described above and thus the brace 80 can include sensors 98 , similar to the sensors 18 of fig5 a ( or similar to sensors 38 or 88 ), which are spaced apart internally within the brace 90 . cooling , fluid mixing , or other methods to harden the liquid can be utilized in the ankle brace in the same way as in the knee brace to transform the ankle brace from the softer more flexible state of fig1 a to the harder more rigid state of fig1 b . the flow chart of fig1 is likewise applicable to the ankle brace 90 of fig1 . the compartments 92 of brace 90 are shown extending vertically in the ankle region , but alternatively can extend diagonally , horizontally , or in other directions as in the knee brace described above . as shown , preferably the columns extend along or across the entire region of the brace so that the entire ankle and adjacent regions are protected . however , it is also contemplated that the columns can extend less than the entire length or provided only in certain regions of the brace so that only select regions of the brace are solidified . additionally , the columns 92 are shown having a width 95 . however , it is also contemplated that the columns can have a shorter width , thereby enabling more columns to be provided , or have thicker width , providing fewer columns . further , the columns need not be of uniform width , but can have varying width . such varying width can provide regions of differing hardness to accommodate various regions of the ankle and adjacent regions , if desired . note for simplicity the sensors are not shown on all the figures , it being understood that figures illustrating views of the same embodiment would have the sensors . also , the sensors illustrated are just one example of how the sensors are positioned , it being understood that a different number of sensors and different locations are also contemplated . while the above description contains many specifics , those specifics should not be construed as limitations on the scope of the disclosure , but merely as exemplifications of preferred embodiments thereof . for example , those skilled in the art will envision many other possible variations that are within the scope and spirit of the disclosure as defined by the claims appended hereto .