referring to fig1 , an open - ended ratcheted wrench 1 includes an elongated handle 6 and a head 2 defining an opening 3 . a work piece 5 can be loaded , e . g ., inserted , into the opening 3 along a direction y that is substantially in line with a longitudinal axis of the elongated handle 6 . such a loading is sometimes called loading from the side . examples of the work piece 5 can include , e . g ., a head of a bolt , a nut , or an in - line fitting . when loaded , portions of one or more surfaces of the work piece 5 engage one or more work piece engaging surfaces , e . g ., surfaces 13 , 15 , 17 , of the head 2 . a user ( not shown ) can turn , e . g ., within the x - y plane , the handle 6 to apply forces or torque to the work piece 5 through the engaged surfaces 13 , 15 , 17 . the work piece 5 can turn around a center 19 ( center of the work piece , or cw ). the user can turn the handle 6 back ( counterclockwise , in a resetting direction r ) and forth ( clockwise , in a driving direction d ) continuously to turn the work piece 5 in the driving direction d , without unloading the work piece 5 from the opening 3 . the operational mechanism of the wrench 1 is further discussed with respect to fig5 and 6 . referring to fig1 , 2 , and 3 a - 3 c , the open - ended wrench 1 has its structure shown . the head 2 includes a pair of stationary jaws 4 , 8 connected to the handle 6 . in some implementations , the stationary jaws 4 , 8 , and the handle 6 are formed , e . g ., machined , as an integral member , e . g ., in a solid piece . the jaw 4 includes an inner work piece engaging surface 13 facing the opening 3 . the work piece engaging surface 13 is stationary relative to the wrench 1 . the jaw 8 supports a movable plate 14 that carries the movable work piece engaging surface 15 , 17 . the work piece engaging surfaces 13 , 15 , 17 can be flat ( fig1 ) or corrugated ( fig2 and 3 a - 3 c ). referring to fig1 , when the work piece 5 is fully loaded in the opening 3 of the wrench 1 , the work piece engaging surfaces 13 , 15 , 17 engage the work piece 5 at an arc 51 ( shown in dotted lines ) of 270 degrees . the adjacent work piece engaging surfaces , e . g ., surfaces 15 , 17 , meet at corner 31 with an angle of 120 degrees . the wrench 1 in fig1 can accommodate hexagonal work piece 5 in a standard or 60 degree rotated position . such an arrangement of the work piece engaging surfaces corresponds to a so - called six point design , because it will accommodate a six cornered hexagonal work piece . the work piece engaging surfaces 13 , 15 have dimensions to engage opposing surfaces of the work piece 5 along the entire length of the surface . surfaces 13 , 15 are further divided into sections 13 a , 13 b and 15 a , 15 b . when the handle 6 is turned in a driving direction , torque is transmitted to work piece 5 through surface sections 13 a , 15 a , 17 . when handle 6 is turned in a ratcheting direction , work piece 5 remains stationary and pressure through surface sections 13 b , 15 b causes the moving plate 14 to partially disengage the surfaces 13 , 15 . referring to fig2 and 3 a - 3 c , the work piece engaging surface 13 , is cut with a notch 40 and surface 15 is cut with notch 42 to accommodate a work piece in a 30 degree rotated position . the wrench 1 thus is a so - called twelve point design because it can accommodate a hexagonal work piece in both a standard and a 30 degree rotated position . the work piece engaging surface 13 includes facets 13 a , 13 b , separated by the notch 40 . the notch 40 includes facets ( or surfaces ) 40 a , 40 b meeting at the corner 31 . each facet ( or surface ) 13 a , 40 b , 40 a , 13 b meets with an adjacent facet ( or surface ) at an angle of 120 degrees . other angles can also be used . the work piece engaging surface 15 includes facets 15 a , 15 b separated by the notch 42 . the notch 42 includes facets ( or surfaces ) 42 a , 42 b meeting at the corner 31 . each facet ( or surface ) 15 a , 42 b , 42 a , 15 b , 17 meets with an adjacent facet ( or surface ) at an angle of 120 degrees . other angles can also be used . when the wrench 1 captures the work piece 5 in a standard position and the handle 6 is turned in a driving direction , torque is applied to the work piece 5 through facets 13 a , 15 a , 17 . when the wrench 1 captures the work piece 5 in a standard position and the handle 6 is turned in a ratcheting direction , work piece 5 remains stationary and pressure to facets 13 b , 15 b causes the moving plate 14 to at least partially disengage the surfaces 13 , 15 . the facet 17 is connected to an overhanging member 28 facing the opening 3 . when the wrench 1 captures work piece 5 in a 30 degree rotated position and the handle 6 is turned in a driving direction , torque is transmitted to the work piece 5 through facets 40 a , 42 a . when wrench 1 captures the work piece 5 in a 30 degree rotated position and the handle 6 is turned in a ratcheting direction , work piece 5 remains stationary and pressure to surface 42 b causes the moving plate 14 to at least partially disengage the surfaces 13 , 15 . referring to fig2 , 3 a , and 3 b , the movable plate 14 slides over a keel 16 of the jaw 8 . a curved outer surface 18 of the movable plate 14 engages a curved inner surface 27 of an outer member 23 of the jaw 8 . the curved outer surface 18 can slide along the inner surface 27 without disengagement . in some implementations , the outer member 23 of the jaw 8 can have the same thickness w as the jaw 4 . the keel 16 extends between the inner surface 27 of the jaw 8 and the jaw 4 , e . g ., the overhanging member 29 . the keel 16 has a thickness t that is a fraction of , e . g ., about ⅓ , the thickness w of the outer member 23 and is located , for example , at the center of the width w . the inner surface 27 is separated into two portions by the keel 16 , each having a width of , e . g ., about ⅓ , thickness w of the outer member 23 . in some implementations , the jaw 8 is larger and more curved than the jaw 4 . the jaw 8 can also protrude from the handle 6 more than the jaw 4 does to accommodate the movable plate 14 . the movable plate 14 has a configuration that allows it to fit onto the jaw 8 . for example , the plate 14 can be arcuately shaped or kidney shaped , and elongated . the movable plate 14 includes a solid , distal end 33 and a slotted proximal end 35 ( fig3 b and 3c ), and can have a thickness q that is substantially the same as the thickness w of the jaw 8 . the slotted proximal end 35 includes two plates 35 a and 35 b separated by a space 45 . when assembled onto the jaw 8 , each plate 35 a , 35 b , of the movable plate 14 sits on either side of the keel 16 and the keel 16 is accommodated in the space 45 . both the curved surface 18 of the movable plate 14 and the curved inner surface 27 of the jaw 8 have the same curvature and are parts of a curved surface ( or arc ) that is centered about a center 39 of the movable plate 14 ( cmp 39 ). the cmp 39 is offset from the center of the engaged work piece ( cw 19 ) ( fig1 ). when the movable plate 14 moves , surface 18 slides along the curved inner surface 27 and the two surfaces 18 , 27 remain engaged . the keel 16 provides strength to the jaw 8 and prevents the movable plate 14 from shifting away from the jaw 4 during loading and operation of the work piece 5 . the cmp 39 is offset from the cw 19 so that moveable plate 14 moves down towards handle 6 and away from cw 19 during ratcheting . in addition to the work piece engaging surface 15 , the movable plate 14 includes a cusp - shaped projection 28 near its distal end that provides the work piece engaging surface 17 . the surface 17 extends at an angle of 120 degrees relative to they axis towards the opening 3 . the projection 28 is short so as not to protrude excessively into the opening 3 . the moveability of the plate 14 and the small size of projection 28 allow the wrench 1 to load the work piece 5 from the side . the additional engaging surface 17 provided by the projection 28 allows the wrench 1 to engage the work piece 5 well . for example , if the work piece 5 is made of a soft material , e . g ., brass or aluminum , it is desirable to capture as many surfaces of the work piece 5 as possible . the movable plate 14 is secured to the jaw 8 using a pin 10 ( fig1 , fig3 a - 3c ) that passes though an arcuate - shaped slot 12 in keel 16 and openings 37 a , 37 b in the plates 35 a , 35 b of the movable plate 14 . the pin 10 can be secured to the movable plate through the openings 37 a , 37 b so that the movement of the pin 10 results in the movement of the movable plate 14 . the arcuate - shaped slot 12 has an upper curved surface 12 a and a lower curved surface 12 b . both curved surfaces 12 a , 12 b are co - centered with the curved surfaces 18 , 27 at the cmp 39 . the slot 12 is larger than the pin 10 which can therefore move between the curves 12 a , 12 b from one proximal end 12 c to a distal end 12 d of the slot 12 , e . g ., without contacting any surface of the slot 12 . the movable plate 14 can be directed to move around the cmp 39 by the movement of the pin 10 . the work piece engaging surfaces of the jaw 4 and the moving plate 14 are laterally spaced from each other by a suitable distance to define the central opening space 3 for receiving the work piece 5 . the space provided between the jaw 4 and the movable plate 14 can allow the work piece 5 to rotate with respect to the stationary jaws 4 , 8 during ratcheting while remaining confined between the jaws 4 , 8 ( further discussed below ). the wrench 1 does not have to be withdrawn from work piece 5 to rotate around the cw 19 of the work piece 5 during the ratcheting action . referring to fig4 , a spring 24 , e . g ., a coil spring , is positioned in the base of the wrench head 2 at the distal end of the handle 6 . one end 41 of the spring 24 is captured within a drilled hole 26 in the wrench head 2 and retained by a plug 32 . the other end 43 of the spring 24 engages the pin 10 and exerts a force f on the pin 10 to push the movable plate 14 towards the opening 3 . spring 24 extends into the slot 12 and engages the portion of the pin 10 that is exposed in the open space 45 between the plates 35 a , 35 b ( fig3 c ). the plates 35 a and 35 b can be shaped and sized , e . g ., elongated , to cover the slot 12 , to prevent disengagement of the spring 24 and the pin 10 , and to protect the spring 24 from dirt or debris . when no other external forces ( other than forces existed in the wrench 1 ) are applied to the movable plate 14 , the spring force f pushes the pin 10 to rest at the distal end 12 d of the slot 12 . the wrench 1 is in a fully locked position without engaging the work piece 5 . when the work piece 5 is held between the jaw 4 and the moving plate 14 , the pin 10 is pushed away from the distal end 12 d of the slot 12 . in some implementations , the dimensions of the slot 12 and the properties of the spring 24 , e . g ., the spring constant , are selected such that during the operation on the work piece 5 , the pin 10 does not substantially contact any surface 12 a - 12 d of the slot 12 . no substantial torque resulting from moving or turning the work piece 5 is transferred through the pin 10 to the jaws 4 , 8 . the pin 10 is used to retain the movable plate 14 and prevent it from falling out of head 2 of the wrench 1 . substantially all forces and torque are transferred through the engaged surface 18 of the movable plate 14 and the surface 27 of the jaw 8 . the pin 10 is manufactured and used in the wrench 1 to endure prolonged wear . the work piece 5 can be loaded by sliding the wrench 1 onto the work piece 5 from the side . initially , an end 45 of the work piece 5 has a width s that is larger than the opening p of head 2 . the user can force the work piece 5 to move forward towards the opening 3 by pushing the movable plate 14 against the spring force f . for example , the moving plate 14 and the pin 10 can be pushed downwards around the cmp 39 to make room for the work piece 5 to enter the space 3 . the spring 24 then pushes against the pin 10 and the movable plate 14 returns to the locked state to grasp the loaded work piece 5 . referring to fig5 and 6 , the driving ( fig5 ) and ratcheting ( fig6 ) operations of the wrench 1 are shown . the user can drive the work piece 5 by continuously turning the wrench handle 6 alternately in the driving direction d ( clockwise , fig5 ) and the ratcheting direction r ( counterclockwise , fig6 ) without withdrawing the wrench 1 from the work piece 5 . during the turn in the driving direction d , the work piece 5 turns and the movable plate 14 remains stationary relative to the stationary jaws 4 , 8 . during the turn in the ratcheting direction r , the work piece 5 is stationary and the movable plate 14 slides towards the wrench handle 6 . referring to fig5 , the work piece 5 is loaded in the opening 3 of the wrench 1 . when the user turns the wrench 1 in the driving direction d ( clockwise ), the stationary jaws 4 , 8 receive a torque from the user &# 39 ; s operation to rotate in the driving direction d . the jaw 4 transfers the torque directly to the work piece 5 through the engaged work piece engaging surface 13 a and the surfaces of the work piece 5 to rotate the work piece in the driving direction d . on the opposite side of the jaw 4 , the jaw 8 transfers rotating torque through the surface 27 to the surface 18 of the moving plate 14 . the work piece engaging surfaces 15 a , 17 of the movable plate 14 then transfer a torque onto the work piece 5 to rotate the work piece in the driving direction d . the turning of the wrench 1 urges the movable plate 14 to move with respect to the stationary jaws 4 , 8 in a direction opposite to the direction d . this urged motion is prevented by the engagement of the surface 18 against the surface 27 of the jaw 8 . the movable plate 14 remains in the locked state and is stationary with respect to the jaws 4 , 8 . the torques transferred from the jaw 4 and the movable plate 14 turns the work piece 5 in the driving direction d . in the 12 point wrench shown in fig3 and 5 , when the work piece 5 is in a 30 degree rotated position , torque is transferred to the work piece 5 through the surface 40 a of jaw 4 and 42 a of moving plate 14 . referring to fig6 , the wrench 1 is rotated in a ratcheting direction r ( counterclockwise ). the surfaces of the work piece 5 exerts a force on the engaged surface 15 b of the movable plate 14 . the force pushes the movable plate 14 against the spring 24 ( fig4 ). the pin 10 slides downwards towards the proximal end 12 c of the slot 12 and the plate 14 slides downwards along the surface 27 of the jaw 8 . the space 3 between the stationary jaw 4 and the movable plate 14 increases , which allows the wrench 1 to ratchet around the work piece 5 . in the 12 point configuration with the work piece 5 in a 30 degree rotated position , the surface of the work piece 5 exerts forces to the movable plate 14 through the surface 42 b when the wrench 1 is rotated in a ratcheting position . when the handle 6 is first rotated in the ratcheting direction r , the pin 10 moves through slot 12 towards the proximal end 12 c , and the surface 18 slides against the surface 27 of the jaw 8 . the movable plate 14 moves from the locked state ( fig5 ) to an unlocked state . therefore , as the handle 6 is rotated in the ratcheting direction r , the movable plate 14 rotates spirally with respect to the stationary jaws 4 , 8 . the spiraling motion of the movable plate 14 is constrained by the movement of the pin 10 and the surface 18 against the surface 27 . the location of the cmp 39 and the orientation of the slot 12 and the surfaces 18 , 27 are chosen so that the movable plate 14 can move downwards and outwards relative to the work piece 5 . the wrench 1 can rotate around the work piece 5 during the ratcheting operation and yet still have sufficient clearance , so that the corners of work piece 5 do not bind against the work piece engaging surfaces 13 , 15 . the surfaces 13 , 15 , 17 of the movable plate 14 and the jaw 4 slide over the surfaces of the work piece 5 , allowing the work piece to remain stationary . in the six - point design shown in fig1 , approximately 60 degrees of handle rotation is required to ratchet the jaw 4 and the movable plate 14 around one corner 49 of the hexagonal work piece 5 . as each corner of the work piece 5 passes across the flat surface 15 into an adjacent cusp 31 , the spring force on the movable plate 14 from the spring 24 causes the movable plate 14 to return to the position shown in fig5 . in the twelve - point design shown in other figures , only 30 degrees of rotation is required before corners of the work piece 5 have moved into an adjacent cusp 31 on the jaw 4 and / or on the moving plate 14 . the driving and ratcheting directions r and d can be reversed by turning the wrench about they axis by 180 degrees , so that in a top view , the jaw 4 is on the right side of the work piece 5 . in this arrangement , the driving direction d is counterclockwise and the ratcheting direction r is clockwise . components of the wrench 1 can be readily manufactured and assembled . materials suitable for use in the components of the wrench 1 include tool steel , hardened steel , or others . different components , e . g ., the stationary jaw 4 , 8 , and the movable plate 14 can be made of the same or different material ( s ). the wrench 1 can be scaled up or down in size and enlarged or miniaturized with respect to standard and metric sized open - ended wrenches . in some implementations , the stationary jaws of the wrench can receive movable plates having different sizes to provide openings 3 with different sizes . a movable plate with a suitable size can be selected and assembled with the jaws of the wrench to accommodate work pieces having a particular size and shape without use a different wrench . for example , the wrench may have an elongated plate with more or fewer work piece engaging surfaces . the movable plate and the stationary jaws can have other shapes . the slot and pin may be reversed , so that the pin is defined in the keel and the slot is defined in the proximal end of movable plate . the wrench handle does not have to be in line with or in the same plane as the jaws . for example , the handle may be offset relative to the jaws by an acute angle in the plane of the jaws , out of the plane of the jaws , or both . the wrench handle and the jaws may be made of separate pieces and connected by a wrist pin . the adjustment of the pin may allow pivoting of the handle upwards or downwards with respect to the plane of the wrench head . the wrench handle may be curved or may have other shapes . the wrench may have a shortened handle embedded with a square hole to accommodate a torque wrench , e . g ., which is known as a crowfoot design . the wrench may have a wrench head , for example , the wrench head 2 , on both ends of the wrench handle . each wrench head can have a first and a second jaws and a movable plate mounted on the second jaw . the first jaw and the movable plate include work piece engaging surfaces that define an opening to receive work pieces . the wrench head on one end of the wrench handle can include an opening having a different size and / or shape than an opening included in the wrench head on the other end of the wrench handle . the two different openings can receive work pieces having different sizes or shapes . other than a coil spring , a flat spring , a flexure , or other types of springs that can engage with the pin and control the movement of the movable plate . the spring may be fixed to the wrench handle or the wrench head in other ways . other open - ended ratchet wrenches are described in u . s . pat . nos . 5 , 456 , 143 , 5 , 829 , 327 , 6 , 223 , 630 , and 7 , 024 , 971 , the entire contents of which are incorporated herein by reference . one or more components of the wrench described in these u . s . patents may be combined with , or incorporated into , the wrench described herein . a number of embodiments have been described . nevertheless , it will be understood that various modifications may be made . other embodiments not specifically described herein are also within the scope of the following claims .