A knife

Abstract

A knife 1 comprising a handle 2 and a blade 4 with an edge 18, a spine 19 opposite the edge 18 and at least one flat side 20 between the edge 18 and the spine 19. The blade 4 and handle 2 are detachably connected by a connection 26 such that a force applied to the spine 19 towards the edge 18 will disconnect the blade from the handle. The blade 4 may be configured to rotate about an axis (30, fig 2) where it connects to the handle 2 when force is applied to the flat side 20. The connection 26 may comprise a magnetic connection that may be configured to hold the blade 4 in line with the handle 2 when no force is applied to the flat side 20. The blade 4 may comprise a tang 24 that may be connected to the connection member 36 by a locking nut 40.

Description

The invention relates generally to a knife. In particular, the invention relates to a knife having a blade and a handle that are detachable and / or rotatably connected to one another. More particularly, the invention relates to a kitchen knife. BACKGROUND In general, knives are designed as tools intended for a specific purpose. However, knives are not usually limited to use for in that specific purpose. Rather, knives may be used instead as an offensive weapon to cause harm to another person. Whilst it is known to provide knives with safety features, such as a providing the blade with a removable or having a retractable blade, such safety features may primarily reduce the risk of injury when the knife is used for its intended purpose. There exists a continued need to reduce the effectiveness of a knife as an offensive weapon (i.e. to reduce the risk of a knife causing a stabbing injury to a person) whilst allow the knife to be used as a tool for its intended purpose. Kitchen knives are in general accessible to the public and are one of the most common type of knives that is used as an offensive weapon. Therefore, there exists a particular need to provide a knife that can be used effectively in the kitchen to prepare food whilst reducing the effectiveness of the knife as an offensive weapon. It is an object of embodiments of the invention to at least mitigate one or more problems associated with known knives. SUMMARY OF THE DISCLOSURE According to an aspect of the invention there is provided a knife comprising: a handle; and a blade comprising an edge, a spine opposing the edge and at least one flat side extending between the edge and the spine; wherein the blade and the handle are connectable to one another by a detachable connection such that a force applied to the spine of the blade in a first direction from the spine to the edge causes the blade to detach from the handle. The detachable connection enable the knife to be used for its intended purpose whilst the blade and handle are connected to one another. However, the detachable connection reduces the effectiveness of the knife as an offensive weapon. If the knife is used a weapon, a defender could apply a force in the first direction to the spine of the knife, for example by hitting the spine of the blade, and cause the detachable connection to separate and the blade to detach (i.e. separate) from the handle thereby reducing risk of injury. The detachable connection may be configured to rotatably connect the blade to the handle about an axis of rotation parallel to the first direction such that a force applied to the flat side causes the blade to rotate about the axis. The force applied to the flat side may be in a second direction that is perpendicular to the first direction. The rotatable connection also reduces the effectiveness of the knife as an offensive weapon. If the knife is used a weapon, the defender could apply a force to one of the flat sides of the blade causing the blade to rotate relative to the handle. This would deflect the blade from the initial trajectory intended by the attacker and thereby reduce risk of an injury being caused. The detachable connection may comprise a magnetic connection. That is, one of the blade and the handle comprises at least one magnet arranged to magnetically engage a corresponding magnet or magnetic material on the other of the blade and the handle. As such, the blade is detachable from the handle when the force applied to the spine of the blade overcomes the engagement of the magnetic connection. 04 03 25 The magnetic connection may be configured to hold the blade in line with the handle in the absence of a force applied to the flat of the blade. Whilst the magnetic connection holds the blade and handle in alignment, the blade is 5 free to rotate when a force is incident on the blade. That is, the knife does not include any means that fixes or locks the blade in the same plane as the handle. The detachable connection may comprise: a projection connected to one of the blade and the handle, the projection comprising a first portion substantially parallel to the io first direction; and a sleeve defining a recess connected to the other of the blade and the handle, the recess being substantially parallel to the first direction and configured to receive the first portion of the projection. The the projection and the recess may each have a substantially circular cross-section 15 such that the blade is rotatable relative to the handle when the projection is within the recess. The knife may comprise a connection member. One end of the connection member is attached to the blade and another opposing end of the connection member comprises 20 one of the projection and the sleeve. The blade may comprise a tang configured to be received by the connection member. The tang of the blade and the connection member may be connected to each other 25 by a locking nut. The sleeve may be configured to extend about the entirety of the circumference of the first portion of the projection when the projection is received by the sleeve. 04 03 25 The projection is connected to the blade and the sleeve may be connected to the handle. The handle may comprise the sleeve. The recess may be configured to receive the projection in a direction opposite to the 5 first direction. Optionally, the magnetic connection may comprise a first magnetic material on a free end of the projection configured to magnetically engage a corresponding first magnetic material in the recess to detachable connect the blade and the handle. io Optionally, the magnetic connection may comprise a second magnetic material extending partially around the circumference of the first portion of the projection and configured to magnetically engage a corresponding second magnetic material in the recess when the blade and handle are in line with each other to hold the blade in line 15 with the handle in the absence of a force applied to the flat of the blade. The second magnetic material on the projection may extend only partially around the circumference of the first portion of the projection. The second magnetic material in the recess may extend only partially around an inner surface of the sleeve. 20 The second magnetic material on the projection may comprise a first strip of magnetic material arranged parallel to the first direction. The second magnetic material in the recess may comprise a second strip of magnetic material having substantially the same width as the first strip, the width being in a direction perpendicular to the first direction. 25 The handle may comprise an engagement portion comprising a third magnetic material arranged to magnetically engage a corresponding third magnetic material on the projection when the blade and handle are in line with one another. The third magnetic material on the handle may be angled at least partially towards the spine of 30 the blade when engaged with the third magnetic material on the projection. 04 03 25 Optionally, the engagement portion may be hingedly connected to the handle. The knife may be a kitchen knife. 5 Optionally, the tip of the blade may be rounded. In certain embodiments an assembly for a knife may be provided. The assembly comprising a handle and a plurality of blades, , each blade of the plurality of blades comprising an edge, a spine opposing the edge and at least one flat side extending io between the edge and the spine. The handle may be interchangeably connectable to each of the plurality of blades by a detachable connection such that a force applied to the spine of the blade in a first direction from the spine to the edge causes the blade to detach from the handle. 15 According to an aspect of the invention there is provided a knife comprising: a handle; and a blade comprising an edge, a spine opposing the edge and at least one flat side extending between the edge and the spine; wherein the blade is rotatable connected to the handle, wherein the blade is 20 rotatable relative to the handle about an axis of rotation parallel to the first direction such that a force applied to the flat side causes the blade to rotate about the axis. The force applied to the flat side may be in a second direction that is perpendicular to the first direction. 25 Optionally, the handle and the blade may be connected to one another by a detachable connection such that a force applied to the spine of the blade in a first direction from the spine to the edge causes the blade to detach from the handle. The detachable connection may be configured to rotatably connect the blade to the handle. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures, in which: Figure 1 shows a exploded view of a knife according to an embodiment of the invention; Figure 2 shows a perspective be of the assembled knife of Figure 1; Figure 3 shows an exploded view of a part of the knife of Figure 1; and Figure 4 shows a perspective view of a part of the knife of Figure 1. DETAILED DESCRIPTION Figure 1 shows a knife 1 according to an embodiment of the invention. As shown in the embodiment in the Figures, the knife 1 may be a kitchen knife 1. The knife 1 comprises a handle 2 and a blade 4. As shown in Figure 1, the handle 2 may comprise a top surface 6 and a bottom surface 8. The bottom surface 8 may comprise a plurality of indentations 10. Each indentation 10 being sized to accommodate a finger of a user of the knife 1. The top surface 6 of the handle 2 may be substantially planar. As shown in the Figures, the handle 2 may comprise two side walls 12,14 extending between the top surface 6 and a bottom surface 8 on opposing sides of the handle 2. One end of the handle 2 may be defined by an end wall 16. The end wall 16 may extend between the top surface 6 and a bottom surface 8 and between the two side walls 12, 14. The other, opposite end of the handle 2, is configured for attached to the blade 4. The blade 4 of the knife 1 comprises an edge 18 and a spine 19 opposing the edge 18. That is, the edge 18 and the spine 19 are on opposing sides of the blade 4. The edge 18 is a cutting edge 18. The edge 18 may extend at least partway along the length of the blade 4. In certain embodiments, the edge 18 may extend substantially along the length of the blade 4. The spine 19 of the knife 1 is unsharpened. The blade 4 has at least one flat side 20 extending between the edge 18 and the spine 19. In the embodiment show in the Figures, the blade 4 comprises two flat sides 20 each extending between the edge 18 and the spine 19 on opposite sides of the blade 4. The two flat sides 20 face in opposite directions to one other. The blade 4 comprises a tip 22 at one end. The tip 22 may extend from the spine 19 to the edge 18. As shown in the embodiment in the Figure, the tip 22 may be rounded. The blade 4 may comprise a tang 24 at one end. The tip 22 and the tang 24 may be at opposite ends of the blade 4. The blade 4 and the handle 2 are connectable to one another by a detachable connection 26. The detachable connection 26 is configured such that, when the blade 4 is attached to the handle 2, a force applied to the spine 19 of the blade 4 in a direction from the spine 19 to the edge 18 of the blade 4 causes the blade 4 to detach (i.e. separate) from the handle 2. That is, the force causes the detachable connection 26 to separate. Through the following, the direction from the spine 19 to the edge 18 of the blade 4 will be referred to as the first direction 28 and is illustrated in Figure 2. During normal orientation of the knife 1 shown in Figure 2, a force in the first direction 28 would coincide with a downward force on the spine 19. This force is in the opposite direction to the force on the blade 4 when using the knife to cut food. As such, the while the blade 4 is detachable from the handle 2, the knife 1 may still be effectively used as a kitchen knife 1. When the blade 4 is attached to the handle 2, the first direction 28 is parallel to a direction from the top surface 6 to the bottom surface 8 of the handle 2. The detachable connection 26 may be configured to rotatably connect the blade 4 to the handle 2 about an axis 30 of rotation parallel to a direction from the spine 19 to the edge 18 of the blade 4 (i.e. parallel to the first direction 28). Therefore, when the blade 4 is attached to the handle 2, a force applied to one of the flat sides 20 of the blade 4 causes the blade 4 to rotate relative to the handle 2 about the axis 30. The detachable 04 03 25 connection 26 therefore couples the blade 4 to the handle 2 so that the blade 4 may rotation relative to the handle 2. The force applied to one of the flat sides 20 may be or comprise a component is perpendicular to the first direction 28. In the embodiment shown in the Figures, a force applied to either one of the flat sides 20 of the blade 4 5 causes the blade 4 to rotate. A force applied to one of the flat sides 20 causes the blade 4 to rotate in the opposite direction to a force applied to the other flat side 20 of the blade 4. The detachable connection 26 may comprise a first coupling member 32 connected io to the handle 2 and a second coupling member 34 connected to the blade 4. The first and second coupling members 32, 34 are configured to releasably engage one other to detachably connect the blade 4 to the handle 2. As shown in the Figures, the handle 2 may comprise the first coupling member 32. The 15 first coupling member 32 and the end wall 16 may be positioned on opposite ends of the handle 2. The first coupling member 32 may be formed as one piece with the handle 2. The second coupling member 34 may be attached to the blade 4 via a connection 20 member 36. The connection member 36 therefore may comprise the second coupling member 34. As shown in the embodiment in the Figures, one end of the connection member 36 may be for attachment to the blade 4 and another opposing end of the connection member 36 may comprise the second coupling member 34. The connection member 36 may help facilitate attaching the second coupling member 34 25 to the blade 4. The connection member 36 and the blade 4 may have different thicknesses where the thickness is in a direction from one flat side 20 to the other flat side 20 of the blade 4. The connection member 36 and the blade 4 may comprise different materials. 30 The connection member 36 may comprise a body 38. The body 38 may be substantially the same height as the blade 4, where the height is the extend of the blade 4 in a direction from the spine 19 to the edge 18 (i.e. parallel to the first direction 28). As described above, the blade 4 may comprise a tang 24. The body 38 may comprise a slot 72 (not shown) on one end for receiving the tang 24. The tang 24 of the blade 4 and the connection member 36 may be connected together a locking nut 40. Each of the tang 24 and the body 38 of the connection member 36 may therefore comprise an aperture 42 for receiving the locking nut 40 therethrough. The detachable connection 26 may comprise a projection 44 and a sleeve 46 defining a recess 48 that is configured to receiving at least part of the projection 44. One of the first and second coupling members 32, 34 comprises the projection 44 and the other of the first and second coupling members 32, 34 comprises the sleeve 46. In the embodiment shown in the Figures, the first coupling member 32, connected to the handle 2, comprises the sleeve 46 and the second coupling member 34, connected to the blade 4 via the connection member 36, comprises the projection 44. Providing the sleeve 46 on the handle 2 and the projection 44 connected to the blade 4 may reduce the risk of the blade 4 detaching from the handle 2 as pressure is placed on the blade 4 during normal use compared to the alternative of the providing the sleeve 46 connected to the blade 4 and the projection 44 on the handle 2 whilst still allows the blade 4 to be detached from the handle 2 by a force on the spine 19 in the first direction 28. As shown in the embodiment in the Figures, the projection 44 may comprise a first portion 50 that is substantially parallel to the first direction 28. The first portion 50 of the projection 44 terminates in a free end 52. The first portion 50 of the projection 44 may have a substantially circular cross-section where the cross-section is in a plane perpendicular to the first direction 28. The first portion 50 of the projection 44 may comprise a side wall 54 and the free end 52. The side wall 54 may be parallel to the first direction 28. The free end 52 may be planar and perpendicular to the side wall 54. The first portion 50 of the projection 44 in the embodiment shown in the Figures is therefore substantially cylindrical in shape. The projection 44 may be attached to the body 38 of the connection member 36 at a first side 60 of the body 38. The free end 52 of the projection 44 may be towards a second side 62 of the body 38. As shown in the Figures, the first side 60 of the body 38 of the connection member 36 is adjacent to or substantially aligned with the edge 18 of the blade 4. The second side 62 of the body 38 is adjacent to or substantially aligned with the spine 19 of the blade 4. The first portion 50 of the projection 44 extends from the end attached to the body 38 to the free end 52 in a direction that is opposite to the first direction 28. The free end 52 of the projection 44 is near the spine 19 of the blade 4. As shown in the embodiment in the Figures, the second coupling member 34 may comprise the sleeve 46. The sleeve 46 comprises an opening 64 at one end for receiving the projection 44. The sleeve 46 may comprises a closed end 66 at the end opposite the opening 64. The sleeve 46 comprises an inner side wall 68. The inner side wall 68 extends from the closed end 66 to the opening 64. As shown in the Figures, the opening 64 of the recess 48 may be positioned towards the bottom surface 8 of the handle 2 and the closed end 66 of the sleeve 46 may be positioned towards the top surface 6 of the handle 2. The sleeve 46 defines the recess 48. Together the closed end 66 and the inner side wall 68 of the sleeve 46 define the shape of the recess 48. The recess 48 is configured to receive the first portion 50 of the projection 44. The recess 48 is substantially parallel to the first direction 28. As shown in the embodiment in the Figures, the recess 48 has a corresponding shape to the first part of the projection 44. The recess 48 may have a substantially circular cross-section where the cross-section is in a plane perpendicular to the first direction 28. The recess 48 may be cylindrical in shape. As such, the inner side wall 68 of the sleeve 46 may be parallel to the first direction 28. The end wall 16 may be planar and perpendicular to the inner side wall 54. The recess 48 may be configured to form a clearance fit with the projection 44. The size of the recess 48 may be slightly larger than the projection 44 such that the projection 44 can slide and rotate within the recess 48. The above-described recess 48 and projection 44 are configured so that when the first portion 50 of the projection 44 is received in the recess 48 a force in the first direction 28 causes the projection 44 to be released from the sleeve 46. This is achieved by the recess 48 being positioned towards the bottom surface 8 of the handle 2 and the projection 44 extending from the end attached to the body 38 to the free end 52 in a direction that is opposite to the first direction 28. Therefore, to insert the projection 44 into the sleeve 46 requires the blade 4 to be moved in a direction that is opposite to the first direction 28. The projection 44 and the sleeve 46 enable the blade 4 to rotate relative to the handle 2 when a force is applied to the flat side 20. The shape and orientation of both the recess 48 and first portion 50 of the projection 44 also allow the projection 44 to be rotate within the recess 48 about the axis 30 of rotation when the first portion 50 of the projection 44 is received in the recess 48. As shown in the Figures, the projection 44 may comprise a second portion 70 disposed between the first portion 50 of the projection 44 and the body 38 of the connection member 36. One end of the second portion 70 of the projection 44 is attached to the body 38 the other is attached to the first portion 50 of the projection 44. As shown in the embodiment in the Figures, the second portion 70 of the projection 44 extends away from the body 38 of the connection member 36 to form a slot 72 between the first portion 50 of the projection 44 and the body 38 of the connection member 36. When the first portion 50 of the projection 44 member is received by the sleeve 46, a part of the sleeve 46 resides in the slot 72. The slot 72 allows the sleeve 46 to extend around the entire circumference of the first portion 50 of the projection 44 member. As shown in the embodiment in the Figures, a part of the second portion 70 of the projection 44 extends away from the body 38 of the connection member 36 in a direction that is substantially parallel to the edge 18 of the blade 4 to form the slot 72. Due to the slot 72, the connection member 36 is U-shaped. The detachable connection 26 may comprise a magnetic connection. That is, one of the first and second coupling members 32, 34 may comprise at least one magnet arranged to magnetically engage a corresponding magnet or magnetic material on the other of the first and second coupling members 32, 34. The magnetic connection may releasably attach the blade 4 to the handle 2. During use, the blade 4 will detach from the handle 2 when the force applied to the spine 19 of the blade 4 is greater than (i.e. overcomes) the engagement of the magnetic connection. The magnetic connection may be configured to hold the blade 4 in line with the handle 2 in the absence of a force applied to the flat of the blade 4. The blade 4 and handle 2 may be considered to be in line when the blade 4 and handle 2 reside substantially in the same plane so that the knife 1 may be used for cutting. Or, in another sense, when the longitudinal axis of the blade 4 is aligned with the longitudinal axis of the handle 2, where the longitudinal axis of the blade 4 extends from the tang 24 to the tip 22 of the blade 4 and the longitudinal axis of the handle 2 extends from the end wall 16 to the first coupling member 32. In the embodiment shown in the Figures, whilst the magnetic connection may hold the blade 4 and handle 2 in line with each other, the blade 4 is free to rotate when a force is incident on the blade 4. The knife 1 does not include any means that fixes or locks the blade 4 in line with handle 2. As shown in the Figures, the magnetic connection may comprise a first magnetic material 74a on the free end 52 of the projection 44 configured to magnetically engage a corresponding first magnetic material 74b in the recess 48. The first magnetic material 74b in the recess 48 may be attached to the closed end 66 of the sleeve 46. The engagement of the first magnetic materials 74a, 74b on the projection 44 and in the recess 48 releasably attach the blade 4 to the handle 2. The engagement of the first magnetic materials 74a, 74b can be overcome by a force in the first direction 28. In the embodiment in the Figures, the first magnetic material 74a on the free end 52 of the projection 44 comprises a substantially circular magnet. The first magnetic material 74b in recess 48 may also comprises a substantially circular magnet shown by the dashed line in Figure 4. The first magnetic material 74b in recess 48 is inside the sleeve 34. The first magnetic material 74a on the projection 44 and the first magnetic material 74b in the recess 48 are aligned with each other when the blade 4 is attached to the handle 2. The magnetic connection may comprise a second magnetic material 76a extending partially around the circumference of the first portion 50 of the projection 44 and a corresponding second magnetic material 76b in the recess 48. The second magnetic material 76b in the recess 48 may extend partially around the inner side wall 68 of the sleeve 46. As shown in the embodiment in the Figures, the second magnetic material 76a on the projection 44 may be on the side wall 54 of the first portion 50 of the projection 44. The second magnetic material 76a on the projection 44 may be arranged to magnetically engage the second magnetic material 76b in the recess 48 when the blade 4 and handle 2 are in line with each other. The second magnetic materials 76a, 76b therefore hold the blade 4 in line with the handle 2 in the absence of a force applied to the flat of the blade 4 so that the knife 1 can be used for cutting. The engagement of the second magnetic materials 76a, 76b may be overcome by a force applied to one of the flat sides 20 of the blade 4 so that the blade 4 may rotate. The engagement of the second magnetic materials 76a, 76b may also be overcome by a force applied to the spine 19 in the first direction 28. The second magnetic materials 76a, 76b may therefore be aligned with and engage one another when the blade 4 and handle 2 are in line but the second magnetic materials 76a, 76b are not aligned and do not engage one another once the blade 4 has been rotated by a predetermined angle relative to the handle 2. Once the second magnetic materials 76a, 76b are not aligned with each other they will not act to hold the blade 4 in a particular position. As such, the second magnetic material 76a on the projection 44 extends only partially around the circumference of the first portion 50 of the projection 44 and the second magnetic material 76b in the recess 48 extends only partially around the around the inner side wall 66 of the sleeve 46. The predetermined angle may be selected depending on the strength of the magnetic engagement, for example, the predetermined angle may be smaller for a strong magnetic engagement compared to a weak magnetic engagement. As shown in the embodiment in the Figures, the second magnetic material 76a on the projection 44 may extend around a quarter or less of the circumference of the first portion 50 of the projection 44 and the second magnetic material 76b in the recess 48 may extend around a quarter or less of the inner side wall 66 of the sleeve 46. As shown in the embodiment in the Figures, the second magnetic material 76a on the projection 44 is a first strip of magnetic material arranged parallel to the first direction 28. The second magnetic material 76b in the recess 48 is a second strip of magnetic material arranged parallel to the first direction 28. The first and second strips have substantially the same width as each other, the width being in a direction perpendicular to the first direction 28. The first and second strips may each be a magnet. The first and second strips are aligned with one another when the blade 4 and handle 2 are in line with each other. The first and second strips magnetically engage each other to hold the blade 4 and handle 2 in alignment. However, once the blade 4 has been rotated by a force applied to one of the flat sides 20 of the blade 4, the first and second strips will no longer be aligned and will not hold the blade 4 in a particular position. The magnetic connection may comprise a third magnetic material 78a on the projection 44 configured to magnetically engage a corresponding third magnetic material 78b on the handle 2 when the when the blade 4 and handle 2 are in line with one another. In a similar manner to the second magnetic materials 76a, 76b, the third magnetic materials 78a, 78b, may hold the blade 4 in line with the handle 2 in the absence of a force applied to the flat of the blade 4 so that the knife 1 can be used for cutting. The engagement of the third magnetic materials 78a, 78b may be overcome by a force applied to the flat of the blade 4 so that the blade 4 rotates. The engagement of the third magnetic materials 78a, 78b may also be overcome by a force applied to the spine 19 in the first direction 28. In the same manner as the second magnetic materials 76a, 76b, the third magnetic materials 78a, 78b are therefore aligned with and engage one another when the blade 4 and handle 2 are in line but the third magnetic materials 78a, 78b are not aligned and do not engage one another once the blade 4 has been rotated by a predetermined angle relative to the handle 2. Once the third magnetic materials 78a, 78b are not aligned with each other they will not act to hold the blade 4 in a particular position. As such, the third magnetic material 78a on the projection 44 extends only partially around the circumference of the projection 44. As shown in the embodiment in the Figures, the third magnetic material 78a on the projection 44 may extend around a quarter or less of the circumference of the projection 44. The third magnetic material 78a on the projection 44 may be on the second portion 70 of the projection 44. The third magnetic material 78a on the projection 44 may be on a curved outer surface of the second portion 70 of the projection 44 which faces towards the handle 2 when the blade 4 and handle 2 are in line. The curved outer surface may be arranged between the part of the second portion 70 of the projection 44 that is parallel to the edge 18 of the blade 4 and the first portion 50 of the projection 44. The handle 2 may comprise an engagement portion 80 for engaging the projection 44. The engagement portion 80 may be positioned adjacent to the bottom surface 8 of the sleeve 46. The engagement portion 80 may be positioned near the opening 64 of the sleeve 46. As shown in the embodiment in the Figures, the third magnetic material 78b on the handle 2 may be positioned on the engagement portion 80. The engagement portion 80 may conform to the shape of the curved outer surface of the projection 44 member. As shown in Figure 1, the third magnetic material 78b on the handle 2 may be angled at least partially towards the spine 19 of the blade 4 when engaged with the third magnetic material 78a on the projection 44. The third magnetic material 78b on the handle 2 therefore engages the third magnetic material 78a on the curved outer surface the projection 44 to both hold the handle 2 in line with the blade 4 and to help attach the blade 4 to the handle 2. The engagement portion 80 may be connected to the rest of the handle 2 by an integral or living hinge. The engagement portion 80 is therefore movable relative to the rest of the handle 2. The engagement portion 80 may be moved between a first position and a second position. In the first position, shown in Figure 2, the engagement portion 80 contacts the projection 44 so that the third magnetic material 78b on the engagement portion 80 engages the third magnetic material 78a on the curved outer surface the projection 44. In the second position, not shown in the Figures, the engagement portion 80 may be adjacent to the bottom surface of the handle 2. The engagement portion 80 may reside in one of the plurality of indentations 10 in the handle 2 when in the second position. The engagement portion 80 may reside in the indentation 10 closest to the sleeve 46. The engagement portion 80 may be clipped onto the indentation 10 when in the second position to secure the engagement portion 80 in the second position. The engagement portion 80 may be clipped onto the indentation by any suitable means (not shown). The engagement portion 80 may be moved from the first to the second position for detaching the blade 4 from the handle 2. As shown in the embodiment in the Figures, the third magnetic material 78a, 78b on the each of the projection 44 and the handle 2 may be a substantially circular magnet. The third magnetic material 78a on the projection 44 may be aligned with the second magnetic material 76a on the projection 44. The third magnetic material 78b on the handle 2 may be aligned with the second magnetic material 76b in the recess 48. During use of the knife 1, the blade 4 is attached to the handle 2 by inserting the first portion 50 of the projection 44 into the recess 48. The magnetic connection attaches the blade 4 and holds the blade 4 in line with the handle 2. During normal use of the knife 1, for example use of the knife 1 in the kitchen for cutting food, the magnetic connection ensures that the blade 4 and the handle 2 are held together in the correct alignment. However, if the knife 1 were used as an offensive weapon the detachable connection 26 reduces the risk of an injury being caused by the knife 1 compared to, for example, a knife 1 where the blade 4 is in a fixed position relative to the handle 2. If the knife 1 is used a weapon, a defender could apply a force in the first direction 28 to the spine 19 of the knife 1, for example by hitting the spine 19 of the blade 4, and cause the blade 4 to be detached from the handle 2 thereby reducing risk of injury. Alternatively, the defender could apply a force to one of the flat sides 20 of the blade 4 causing the blade 4 to rotate relative to the handle 2. This would deflect the blade 4 from the initial trajectory intended by the attacker and thereby reduce risk of an injury being caused. The defender could apply either of the forces to the blade 4 the during self-defence. In certain embodiments, the knife 1 may be provided with a plurality of blades 4. Each of the plurality of blades 4 is configured to be detachably connected to the same (i.e. one) handle 2. A second coupling member 34 that is the same as the above described may be connected to each of the plurality of blades 4. Each of the plurality of blades 4 may be interchangeable connected to the handle 2. Each of the blades 4 may be different to each other. For example, the difference between the blades 4 may be in the shape and intended use. For example, the blades 4 may have different lengths and / or the edge 18 of the blades 4 may differ (i.e. the edge 18 may be serrated or non-serrated). The skilled person will appreciate that various modifications can be made to the abovedescribed embodiment without departing from the scope of the invention. In the above-described embodiment, the knife 1 is a kitchen knife 1. However, the skilled person will appreciate that the detachable connection 26 is not limited to use on a kitchen knife 1 but may be used on knives intended for other purposes. In alternative embodiments, the connection member 36 may be omitted. In such embodiments, the second coupling member 34 may be one piece with the blade 4. In alternative embodiments to the above-described embodiments, the first coupling member 32 may comprise the projection 44 and the second coupling member 34 may comprise sleeve 46. The skilled person will appreciate that the magnetic connection may be achieved in a different manner to the above described first, second and third magnetic materials. For example, a different number and arrangement of magnetic materials may be used to provide the magnetic connection. In the above-described embodiment, the blade 4 is both detachable from and rotatable relative to the handle 2. In alternative embodiments, the blade 4 may not be detachable relative to the handle 2. In other alternative embodiments, the blade 4 may not be rotatable relative to the handle 2. In such embodiments, the projection 44 and recess 48 may not have a circular cross-section. For example, the projection 44 and the recess 48 may have square, hexagonal or any other suitable alternative cross-section. Additionally or alternatively, the projection 44 may form a friction or interference fit with the recess 48. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings). The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments falling within the scope of the claims. Each feature disclosed in this specification (including any accompanying claims and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. All of the features disclosed in this specification (including any accompanying claims and drawings) may be combined in any combination, except combinations where at least some of such features are mutually exclusive. The invention is defined by the appended claims.

Claims

1. A knife comprising: a handle; and5 a blade comprising an edge, a spine opposing the edge and at least one flat side extending between the edge and the spine;wherein the blade and the handle are connectable to one another by a detachable connection such that a force applied to the spine of the blade in a first direction from the spine to the edge causes the blade to detach from the handle.io2. A knife according to claim 1, wherein the detachable connection is configured to rotatably connect the blade to the handle about an axis of rotation parallel to the first direction such that a force applied to the flat side causes the blade to rotate about the axis.

153. A knife according to any one of the preceding claims, wherein the detachable connection comprises a magnetic connection.

4. A knife according to claim 3, wherein the magnetic connection is configured 20 to hold the blade in line with the handle in the absence of a force applied to the flat of the blade.

5. A knife according to any one of the preceding claims, wherein the detachable connection comprises:25 a projection connected to one of the blade and the handle, the projectioncomprising a first portion substantially parallel to the first direction; anda sleeve defining a recess connected to the other of the blade and the handle,the recess being substantially parallel to the first direction and configured to receive the first portion of the projection.3004 03 256. A knife according to claim 5, wherein the projection and the recess each have a substantially circular cross-section such that the blade is rotatable relative to the handle when the projection is within the recess.5 7. A knife according to claim 5 or 6, comprising a connection member, one endof the connection member is attached to the blade and another opposing end of the connection member comprises one of the projection and the sleeve.

8. A knife according to claim 7, wherein the blade comprises a tang configured io to be received by the connection member.

9. A knife according to claim 8, wherein the tang of the blade and the connection member are connected by a locking nut.15 10. A knife according to any one of claims 5 to 9, wherein the sleeve isconfigured to extend about the entire circumference of the first portion of the projection when the projection is received by the sleeve.

11. A knife according to any one of claims 5 to 10, wherein the projection is 20 connected to the blade and the sleeve is connected to the handle.

12. A knife according to any one of claims 5 to 11, when dependent on claim 3, wherein the magnetic connection comprises a first magnetic material on a free end of the projection, the first magnetic material being configured to magnetically engage a 25 corresponding first magnetic material in the recess to detachable connect the blade and the handle.

13. A knife according to any one of claims 5 to 12, when dependent on claim 4, wherein the magnetic connection comprises a second magnetic material extending 30 partially around the circumference of the first portion of the projection and configured04 03 25to magnetically engage a corresponding second magnetic material in the recess when the blade and handle are in line with each other to hold the blade in line with the handle in the absence of a force applied to the flat of the blade.5 14. A knife according to claim 13, wherein the second magnetic material on theprojection comprises a first strip of magnetic material arranged parallel to the first direction and wherein the second magnetic material in the recess comprises a second strip of magnetic material having substantially the same width as the first strip, the width being in a direction perpendicular to the first direction.io15. A knife according to according to any one of claims 5 to 14, when dependent on claim 3, wherein the handle comprises an engagement portion comprising a third magnetic material arranged to magnetically engage a corresponding third magnetic material on the projection when the blade and handle are in line with one another; and 15 wherein the third magnetic material on the handle is angled at least partially towards the spine of the blade when engaged with the third magnetic material on the projection.

16. A knife according to claim 15, wherein the engagement portion is hingedly connected to the handle.2017. A knife according to any one of the preceding claims, wherein the knife is a kitchen knife.

18. A knife according to any one of the preceding claims, wherein the tip of the 25 blade is rounded.

19. An assembly for a knife comprising:a handle; andLO CXICOa plurality of blades,, each blade of the plurality of blades comprising an edge, a spine opposing the edge and at least one flat side extending between the edge and the spine;wherein the handle is interchangeably connectable to each of the plurality of5 blades by a detachable connection such that a force applied to the spine of the blade in a first direction from the spine to the edge causes the blade to detach from the handle.

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