WO2019197544A1

WO2019197544A1 - A manual device with two heads

Info

Publication number: WO2019197544A1
Application number: PCT/EP2019/059282
Authority: WO
Inventors: Victor D'HALLUIN; Laurent Mazingue; Laurent Beaucher
Original assignee: Societe Bic
Priority date: 2018-04-11
Filing date: 2019-04-11
Publication date: 2019-10-17
Also published as: FR3080059A1

Abstract

A manual device, in particular a writing instrument, comprising a body (10) extending along an axial direction between a front end and a rear end, a first head (20) having a first function, a second head (30) having a second function, and a changeover mechanism (50), wherein the first and second heads (20, 30) are movably mounted relative to each other between a stable first state in which the second head (30) is situated towards the rear in the axial direction relative to the first head (20), and an unstable, second state in which the second head (30) is situated level with or in front of the first head (20) in the axial direction, and wherein the changeover mechanism (50) is configured, when actuated, to move the first and second heads (20, 30) to their second state against a return force from a return member (60), and when not actuated, to allow the first and second heads (20, 30) to return to their first state under the effect of the return force of the return member (60).

Description

A MANUAL DEVICE WITH TWO HEADS

FIELD OF THE INVENTION

[0001] The present disclosure relates to a manual device, in particular a writing instrument, that has two heads that can be used as alternatives. In particular, the instrument may be a writing instrument having a writing head and an eraser head, and in particular a writing instrument using thermochromic ink.

STATE OF THE PRIOR ART

[0002] Nowadays, there exist numerous writing

instruments that combine a writing head and an eraser head within the same body.

[0003] Whether for a mechanical pencil, or for a pen with erasable ink or indeed thermochromic ink, the most conventional configuration remains the configuration in which the eraser head, whether a rubber eraser, a

chemical eraser, or a friction body, is provided at the rear end of the writing instrument, opposite from the writing head.

[0004] That configuration presents the advantage of being the easiest to design and make; nevertheless, it is not very ergonomic or comfortable to use since it

requires the writing instrument to be turned over each time it is desired to use the eraser head: this therefore leads to a loss of time and to a break in the user's concentration .

[0005] Other configurations also exist in which the eraser head can be operated so as to project from the front end of the writing instrument, instead of from or around the writing head, whenever that is desired.

Nevertheless, under such circumstances, the operation needed to extend the eraser head requires one or more buttons to be manipulated that are often situated close to the rear end of the writing instrument, i.e. out of reach of a user's fingers under normal writing conditions: the user is thus constrained to change grip on the writing instrument, thereby once more slowing down execution and breaking the user's concentration.

Furthermore, those mechanisms need to be manipulated not only when extending the eraser head, but also when retracting it, thereby doubling the number of

interruptions to work and the time lost as a result.

[0006] There therefore exists a real need for a manual device, in particular a writing instrument, that is provided with at least two heads that can be used as alternatives and that does not suffer, at least in part, from the drawbacks inherent to the above-mentioned known configurations .

SUMMARY OF THE INVENTION

[0007] The present disclosure provides a manual device, in particular a writing instrument, comprising a body extending along an axial direction between a front end and a rear end, a first head having a first function, a second head having a second function, and a changeover mechanism, wherein the first and second heads are ovably mounted relative to each other between a stable first state in which the second head is situated towards the rear in the axial direction relative to the first head, and an unstable second state in which the second head is situated level with or in front of the first head in the axial direction, and wherein the changeover mechanism is configured, when actuated, to move the first and second heads to their second state against a return force from a return member, and when not actuated, to allow the first and second heads to return to their first state under the effect of the return force of the return member.

[0008] By means of such a manual device, it is

possible to activate the second head quickly and easily when so desired and then to return immediately to the first head, automatically and without loss of time, when it is no longer desired to use the second head. [0009] In particular, no manipulation is needed to return to the first state: it suffices to cease actuating the changeover mechanism in order to return to the first state under the effect of the return member. Thus, user manipulation is required only once, when the user desires to use the second head.

[0010] Such operation is particularly ergonomic in that the second head of such a manual device generally requires greater force and/or attention in use but for a duration that is quite short, which is compatible with maintaining actuation of the changeover mechanism during that period.

[0011] In the present disclosure, the axial direction corresponds to the direction of the axis of the body, and a radial direction is a direction perpendicular to the axis of the body. It can be understood that an azimuth or circumferential direction corresponds to a direction describing a ring around the axial direction.

Furthermore, unless specified to the contrary, the adjectives "inside'V'outside" or "inner"/"outer" are used relative to a radial direction in such a manner that an inner portion (i.e. a radially inner portion) is closer to the axis of the body than is an outer portion (i.e. radially outer portion) . The term "axial plane"

designates a plane containing the axis of the body, while the term "radial plane" designates a plane perpendicular to the axis. It can also be understood that the body presents a front end where at least the first head is provided, and a rear end that is opposite in the axial direction from the front end. Consequently, unless specified to the contrary, the terms "front" or "rear" should be understood as "arranged beside the front or rear end". The term "finger" is used to designate any digit of the hand, including a thumb.

[0012] In certain embodiments, the first and second heads are coaxial. This leads to great compactness and makes it possible to advance one of the heads forward without necessarily moving the other head.

[0013] In certain embodiments, the second head

surrounds the first head. This enables the second head to be given a large working area and leaves considerable freedom in designing the size and the fineness of the first head.

[0014] In certain embodiments, the first head is provided at the front end of the body. Specifically, the front end of the body is the end of the manual device that is to be pointed towards the working surface.

[0015] In certain embodiments, the second head is provided at the front end of the body. In this way, it is possible to use the second head without turning the manual device around, thereby making it more ergonomic and easier to use.

[0016] In certain embodiments, one of the first and second heads is mounted to move relative to the body and the other one of the first and second heads is stationary relative to the body. This serves to simplify the changeover mechanism and thus reduce the cost of

fabrication and the risk of the changeover mechanism jamming .

[0017] In certain embodiments, the first head and/or the second head is mounted to move in translation

relative to the body.

[0018] In certain embodiments, the first head is a writing head. A writing head is particularly appropriate for the first head, i.e. the main head, since the main function of a writing instrument is writing. In the meaning of the present disclosure, a writing head may for example be a felt tip, a ball or other point, a graphite lead, a mechanical pencil mechanism, a chalk, and more generally any means suitable for writing on a substrate; or any (active or passive) endpiece configured to co operate with a touch screen, e.g. a capacitive,

resistive, inductive, infrared, optical, electrostatic, etc. screen. Nevertheless, in other embodiments, the first head could be any other tool endpiece for a manual device, e.g. an endpiece comprising a key, a screwdriver, a blade, a punch, a cosmetics applicator (brush, pencil, mascara brush, roll-on applicator, lipstick, or any other means for applying cosmetics) , etc.

[0019] In certain embodiments, the first head is a writing head of the thermochromic ink type. The term "thermochromic ink" is used for an ink that changes color, possibly becoming colorless, as a function of the temperature to which it is subjected.

[0020] In certain embodiments, the second head is an eraser head. An eraser head is particularly suitable as the second head, which is secondary and temporary, since an eraser head is intended for occasional use only and for a duration that is quite short while writing. In the meaning of the present disclosure, an eraser head may for example be a rubber eraser, a chemical eraser, a

dispenser of liquid or solid concealer, a friction body, etc.; or any (active or passive) endpiece configured to co-operate with a touch screen in order to erase a digital mark.

[0021] In certain embodiments, the second head is an eraser head of the friction member type. It can be understood that a friction body is a body that is

configured to be rubbed against a working surface, e.g. in order to generate heat and cause a thermochromic ink to change color or to erase.

[0022] In certain embodiments, the manual device includes at least one actuator member that is configured to actuate the changeover mechanism.

[0023] In certain embodiments, at least one actuator device is configured to actuate the changeover mechanism when pressure is applied thereon. Thus, merely applying pressure suffices to actuate the changeover mechanism without it being necessary to perform any complex

manipulation. Thus pressure can be exerted easily and without paying any special attention or losing

concentration, while simultaneously making use of the second head: in particular, when the second head is an eraser head, the user naturally exerts stronger pressure on the body of the writing instrument, thereby providing use that is ergonomic.

[0024] In certain embodiments, at least one actuator member is provided in a grip zone of the body. This preferably applies to all of the actuator members when the manual device has more than one. Thus, the actuator member comes naturally under the fingers of the user while using the first head, so the user can activate the second head without changing the position of the fingers, merely by pressing harder on the body of the manual device, and thus on the actuator member, without changing grip, and can subsequently relax the grip in order to return automatically to the first head. The user can thus change from the first head to the second, and vice versa, without changing grip on the manual device: this makes the device much more ergonomic and comfortable to use, thereby achieving a particularly large saving in time and in concentration.

[0025] It can be understood that the grip zone of the body is the zone where the user naturally places the fingers during normal use of the manual device. In particular, it is the front portion of the body,

generally the front half or third of the body. This grip zone may be provided with a particular grip coating of material that is different from the material of the remainder of the body so as to prevent the user's fingers from sliding along the body. The grip zone may thus have a coefficient of friction that is greater than the remainder of the body; it may also have greater

elasticity and/or flexibility. The grip zone may also include ergonomic projections or cutouts making the body more ergonomic to grip. [0026] In certain embodiments, at least one actuator member is of pushbutton type.

[0027] In certain embodiments, at least one actuator member comprises a pivot portion hinged to the body.

[0028] In certain embodiments, at least one actuator member comprises a press portion configured to receive pressure from a finger of a user, this press portion preferably being rounded. The press portion thus

projects from the body, thereby making it easier to identify merely by coming into contact with the fingers of the user.

[0029] In certain embodiments, at least one actuator includes an actuator portion that is directed towards the inside of the body and configured to actuate the

changeover mechanism.

[0030] In certain embodiments, the manual device has two actuator members. It is thus possible to actuate the changeover mechanism by pinching the two actuator members between two fingers.

[0031] In certain embodiments, the two actuator members are situated in half-planes forming an angle lying in the range 160° to 200°, preferably equal to about 180°.

[0032] In certain embodiments, the two actuator members are offset relative to each other, axially along the body.

[0033] In certain embodiments, the changeover

mechanism comprises a movable carriage secured to one of the first and second heads, the carriage including at least one cam surface configured to co-operate with the actuator member.

[0034] In certain embodiments, at least one cam surface is a ramp. The ramp may in particular be linear.

[0035] In certain embodiments, the carriage includes a central bore that receives a rod. Co-operation between the bore and the rod forms a sliding pivot type

connection . [0036] In certain embodiments, said rod is a cartridge feeding one of the first and second heads, preferably the first head.

[0037] In certain embodiments, the manual device does not have a blocking mechanism for blocking the first and second heads in their second state. As explained above, by default, the manual device is in the first state with the first head in front: the changeover to the second state, in which the second head is in front, is only temporary and is not stable, this state being maintained only for as long as the changeover mechanism is actuated. Thus, as soon as the user releases actuation of the changeover mechanism, the return member automatically returns the manual device into its first state.

[0038] In certain embodiments, the first head is movable .

[0039] In certain embodiments, the second head is a front end portion of the body.

[00 0] In certain embodiments, in the second state, the first head is retractable into the front end portion of the body.

[0041] In certain embodiments, the end portion of the body is formed by an endpiece, preferably a tapering endpiece, that is fitted on a main portion of the body.

It may be removable or non-removable. Nevertheless, in other embodiments, this front end portion of the body may be an integral portion of the body.

[0042] In certain embodiments, the return member is provided at the rear end of the body. Such a

configuration serves to release room at the front of the body, thereby making it easier to integrate the

changeover mechanism and the actuator members.

[0043] In certain embodiments, the return member is arranged so as to exert a resilient force on the first head. This creates a damping effect on the first head, thereby serving to increase comfort of use and

flexibility while writing. [0044] In certain embodiments, the return member is provided between the rear end portion of the body and a rod secured to the first head.

[0045] In certain embodiments, the return member is a spring. The spring is preferably a helical spring mounted in compression.

[0046] In certain embodiments, the rear end portion of the body is a cover fitted on a main portion of the body. The cover may be removable or not removable.

Nevertheless, in certain embodiments, this rear end portion of the body may form an integral portion of the body .

[0047] In certain embodiments, a bushing, having two cylindrical cavities, is interposed between the return member and the rod secured to the first head.

[0048] In certain embodiments, the second head is movable .

[0049] In certain embodiments, the second head

comprises a sheath, the sheath completely surrounding the working portion of the first head in the second state.

The sheath is thus interposed between the first head and the working surface in such a manner as to prevent the first head from touching the working surface.

[0050] In certain embodiments, the return member is provided at the front end of the body.

[0051] In certain embodiments, the return member is provided between a shoulder of the front end portion of the body and a shoulder of the carriage.

[0052] In certain embodiments, the front end portion of the body is provided with a plurality of resilient tongues configured to mask the second head in the first state, and to allow the second head to project in the second state.

[0053] In certain embodiments, the manual device includes a protection mechanism configured to mask the first head when the manual device is not in use. [0054] In certain embodiments, the protection

mechanism comprising a mechanism for retracting the first head inside the body. Nevertheless, in other

embodiments, it could be a separate cap or a stretchable sheath .

[0055] The above characteristics and advantages, and others, appear on reading the following detailed

description of embodiments of the proposed manual device. The detailed description refers to the accompanying drawings .

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings are diagrammatic and they seek above all to illustrate the principles of the disclosure .

[0057] In the drawings, from one figure to another, elements (or portions of an element) that are identical are referenced by the same reference signs. In addition, elements (or portions of an element) belonging to

different embodiments but having functions that are analogous are referenced in the figures by numerical references that are incremented by 100, 200, etc.

Figure 1 is a perspective view of a first example writing instrument.

Figure 2 is an exploded view of the first example writing instrument.

Figure 3 is a section view of the first example writing instrument in its first utilization state.

Figure 4 is a section view of the first example writing instrument in its second utilization state.

Figure 5 is a perspective view of a second example writing instrument.

Figure 6 is an exploded view of the second example writing instrument .

Figure 7 is a section view of the second example writing instrument in its first utilization state. Figure 8 is a section view of the second example writing instrument in its second utilization state.

DETAILED DESCRIPTION OF EMBODIMENTS

[0058] In order to make the disclosure more concrete, examples of writing instruments are described in detail below with reference to the accompanying drawings. It should be recalled that the invention is not limited to these examples.

[0059] Figure 1 is a perspective view of a first embodiment of a writing instrument 1. Externally, this writing instrument 1 presents a body 10 extending axially along a main direction A between a front end lOv and a rear end lOr, a writing tip 21 projecting from the front end lOv of the body 10, and two buttons 40 forming actuator members.

[0060] The front end 10v of the body includes an endpiece 11 having a front portion that forms a second head 30. In the present example, the writing tip 21, belonging to a writing head 20 forming a first head, is a ballpoint fed with thermochromic ink coming from a cartridge 22 (see Figure 2), and the second head 30 is made of a material having a large coefficient of friction so as to constitute a friction member that, when rubbed against a working surface such as a piece of paper, is capable of generating sufficient heat to bleach the thermochromic ink of the writing tip 21.

[0061] As can be seen in Figure 1, the two buttons 40 are arranged in a grip zone P of the body 10, i.e. the zone occupying substantially the front third of the body 10 where the user places fingers while using the writing instrument 1. More precisely, in this example, the two buttons 40 are arranged in the same axial plane on either side of the body 10 and they are axially offset relative to each other.

[0062] Figure 2 shows the various members of the writing instrument 1 in a disassembled state, while Figure 3 shows the same members, in section, in the first utilization state of the writing instrument 1.

[0063] It can thus be observed that the body 10 has a main portion 12, the endpiece 11 mounted as a force-fit or screwed in the front end of the main portion 12, and a cover 13 having a thread 13a enabling it to be releasably mounted on the rear end of the main portion 12, which itself is tapped.

[0064] The body 10 receives the writing head 20 including the writing tip 21 and its cartridge 22, the writing tip 21 projecting from the front end lOv of the body 10 through a central orifice 11a in the endpiece 11.

[0065] The body 10 also houses a changeover mechanism 50 comprising a carriage 51. The carriage 51 is

substantially cylindrical in shape and has an axial bore 52 together with two cutouts forming ramps 53 that act as cam surfaces, the ramps 53 being positioned in the same axial plane and being axially offset relative to each other so that each of them co-operates with a different one of the buttons 40.

[0066] When assembling the writing instrument 1, the writing head 20 is threaded through the bore 52 of the carriage 51 until a shoulder 23 of the writing head 20 comes into abutment against an inner shoulder 54 of the bore 52 of the carriage 51 and until the carriage 51 comes into abutment against the end wall of the endpiece 11. Thus, by means of this co-operation, when the carriage 51 is moved rearwards, it takes with it the writing head 20, and when the writing head 20 is moved forwards, it takes with it the carriage 51.

[0067] The body 10 also houses a helical spring 60 forming a return member, together with a bushing 61. The bushing 61 is substantially cylindrical and has two axial cavities 62 and 63. The bushing 61 is mounted so as to engage its front cavity 62 around the rear end of the cartridge 22 of the writing head 20. The spring 60 is mounted in the rear cavity 63 of the bushing 61 and becomes compressed between the bushing 61 and the end wall of the cover 13: thus, once assembled, the spring 60 continuously exerts a resilient return force on the writing head 20 so as to urge it forwards.

[0068] The main portion 12 of the body 10 has two openings 14 of dimensions and positions suitable for receiving the buttons 40. Each button 40 has a pivot portion 41, a press portion 42, an actuator portion 43, and two retaining portions 44. The pivot portion 41 is pivotally mounted on a tongue 15 of the body 10,

extending from the front edge of the corresponding opening 14, while the retaining portions 44 engage inside the body 10 on either side of the opening 14 so as to hold the button 40 to the body 10. The press portion 42 is rounded and outwardly directed so as to receive pressure from a finger of the user.

[0069] The actuator portion 43 is provided on the back of the press portion 42 at the end of the button 40 that is remote from the pivot portion 41: the actuator portion 43 of each button 40 is configured to co-operate with a coinciding ramp 53 of the carriage 51.

[0070] As can be seen in Figure 4, which shows the second utilization state of the writing instrument 1, when the press portion 42 of a button 40 is pressed, its actuator portion 43 bears against the coinciding ramp 53, thereby pushing the carriage 51, and thus the writing head 20 towards the rear against the return force of the spring 60.

[0071] Thus, when the user seeks to use the writing instrument 1, the user proceeds as follows. While writing, or drawing, the user holds the body 10 of the writing instrument 1 by placing fingers in the grip zone P, two fingers preferably being positioned on the buttons 40 but without pressing on them. Under such

circumstances, the writing instrument 1 is in its first utilization state, as shown in Figure 3: the writing tip 21 projects from the front lOv of the body through the orifice 11a in the endpiece 11. The user can then write or draw in normal manner by pressing the writing tip 21 on a working surface such as a piece of paper. When this happens, each time the writing tip 21 presses against the working surface that pressure is damped by the spring 60.

[0072] Thereafter, when the user seeks to erase a mark, the user grips the body 10 of the writing

instrument 1 more strongly so as to exert pressure on the buttons 40. As a result, and as explained above, this causes the carriage 51 to reverse together with the writing head 20 against the return force of the spring 60. The writing instrument 1 then occupies its second utilization state, as shown in Figure 4: the writing tip 21 is retracted within the endpiece 11 so that the friction member 30 of the endpiece 11 is the lowest portion at the front of the writing instrument 1. The user can then rub the friction body 30 on the working surface so as to erase the erroneous mark.

[0073] Finally, when the erroneous mark has been erased and the user seeks to continue writing or drawing, the user relaxes the pressure exerted on the buttons 40. Consequently, the spring 60 pushes the writing head 20 together with the carriage 51 forwards until the writing tip 21 projects once more from the front lOv of the body 10. This returns to the first utilization state shown in Figure 3.

[0074] Figures 5 to 8 show a writing instrument 101 in a second embodiment .

[0075] Externally, this writing instrument 101

presents a body 110 extending axially along the main direction A between a front end llOv and a rear end llOr, a writing tip 121 projecting from the front end llOv of the body 110, and a single button 140 forming an actuator member .

[0076] The front end llOv of the body 110 has an endpiece 111 with a front portion that includes an X- shaped cutout 111a forming four resilient tongues 111b, the writing tip 121 projecting through the X-shaped cutout 111a.

[0077] In this second example, the writing tip 121 of the writing head 120 is likewise a ballpoint fed with thermochromic ink coming from a cartridge 122. In contrast, the friction body is not provided on the endpiece 111 but is now in the form of a sheath 130 arranged coaxially around the writing tip 121 and movable between a retracted position inside the endpiece 111 and a projecting position in which the sheath 131 projects around the writing tip 121 through the X-shaped cutout 111a of the endpiece 111.

[0078] Once more, the button 140 is arranged in the grip zone P of the body 110, i.e. in the zone occupying substantially the front third of the body 110 where a user places fingers when using the writing instrument 1.

[0079] In this second example, the body 110 also has a main portion 112, the endpiece 111 mounted as a force-fit in the front end of the main portion 112, and a cover 113 provided with a thread 113a enabling it to be releasably mounted on the rear end of the main portion 112 that is provided with tapping .

[0080] The body 110 houses the writing head 120 comprising the writing tip 121 and its cartridge 122.

[0081] The body 10 also houses a changeover mechanism 150 operating in a manner that is substantially analogous to that of the first example, except that in this example it is the friction body 130 that is movable while the writing head 120 is stationary. Thus, the changeover mechanism 150 comprises a carriage 151 of substantially cylindrical shape having an axial bore 152 together with a cutout forming a ramp 153 acting as a cam surface. The carriage 151 also has a front axial cavity 154 in which the sheath 130 is mounted as a force-fit.

[0082] When assembling the writing instrument 101, the writing head 120 is threaded through the bore 152 of the carriage 151. The resulting assembly is then inserted in the body 110 after a spring 160. Thus, once mounted, the spring 160 continuously exerts a resilient return force on the carriage 151 so as to urge it rearwards.

[0083] A bushing 161 is then inserted after the writing head 120, with the cartridge 122 being inserted as a force-fit in the front cavity 162 of the bushing 161. Once the cover 113 of the body 110 has been fitted on the main portion 112 of the body, the position of the bushing 161 is fixed, thereby in turn fixing the position of the writing head 120: the position of the writing tip 121 is thus permanently fixed relative to the body 110.

[0084] The main portion 112 of the body 110 includes an opening 114 of dimensions and position suitable for receiving the button 140. The button 140 likewise has a pivot portion 141, a press portion 142, an actuator portion 143, and two retaining portions 144, and it is mounted in a manner analogous to the first example on a tongue 115 of the body 110.

[0085] Thus, and as can be seen in Figure 8, which shows the second utilization state of the writing

instrument 1, when the press portion 142 of the button 140 is pressed, its actuator portion 143 bears against the ramp 153, thereby pushing the carriage 151 and thus the sheath 130 forwards against the return force of the spring 160.

[0086] Thus, when the user desires to use the writing instrument 101, the user proceeds as follows. During a stage of writing or of drawing, the user takes hold of the body 110 of the writing instrument 101 by placing fingers over the grip zone P, with at least one finger preferably being positioned on the button 140, but without pressing on it. Under such circumstances, the writing instrument 101 is in its first utilization state, as shown in Figure 7: the movement tip 121 projects from the front llOv of the body 110 through the X-shaped orifice 111a in the endpiece 111. The user can then write or draw normally by pressing the writing tip 121 against a working surface, such as a piece of paper.

[0087] Thereafter, when the user seeks to erase a mark, the user grips the body 110 of the writing

instrument 101 more firmly in order to exert pressure on the button 140. Under such circumstances, and as

explained above, this causes the carriage 151 and thus the sheath 130 to move forwards against the return force of the spring 160. The writing instrument 101 is then in its second utilization state, as shown in Figure 8: the sheath 130 is then in its projecting position, pushing apart the resilient tongues 111b of the endpiece 111 so as to project from the front end llOv of the body while completely surrounding the writing tip 121. The writing tip 121 is thus masked by the sheath 130 and the user can then rub the sheath 130 against the working surface so as to erase the erroneous mark.

[0088] Finally, once the erroneous mark has been erased and the user desires to return to writing or drawing, the user releases the pressure being exerted on the button 140. Consequently, the spring 160 pushes back the carriage 151 together with the sheath 130 in a rearward direction until the sheath 130 is once more retracted inside the endpiece 111 and the writing tip 121 is once more accessible at the front 110b of the body

110. This returns to the first utilization state shown in Figure 7.

[0089] Although the present invention is described with reference to specific embodiments, it is clear that modifications and changes could be carried out thereon without going beyond the general scope of the invention as defined by the claims. In particular, individual characteristics of the various embodiments shown and/or mentioned may be combined in additional embodiments.

Consequently, the description and the drawings should be considered in a sense that is illustrative rather than restrictive . [0090] It is also clear that all of the characteristics described with reference to a method are transposable, singly or in combination, to a device, and conversely all of the characteristics described with reference to a device can be transposed, singly or in combination, to a method.

Claims

1. A manual device, in particular a writing instrument, comprising :

a body (10) extending along an axial direction (A) between a front end (lOv) and a rear end (lOr) ;

a first head (20) having a first function;

a second head (30) having a second function; and a changeover mechanism (50);

wherein the first and second heads (20, 30) are movably mounted relative to each other between a stable first state in which the second head (30) is situated towards the rear in the axial direction (A) relative to the first head (20) , and an unstable second state in which the second head (30) is situated level with or in front of the first head (20) in the axial direction (A); wherein the changeover mechanism (50) is configured, when actuated, to move the first and second heads (20,

30) to their second state against a return force from a return member (60) and, when not actuated, to allow the first and second heads (20, 30) to return to their first state under the effect of the return force of the return member (60); and

wherein the first head is a writing head (20) .

2. A manual device according to claim 1, wherein the first and second heads (20, 30) are coaxial, the second head (30) surrounding the first head (20) .

3. A manual device according to claim 1 or claim 2, wherein the first head (20) is a thermochromic ink writing head.

4. A manual device according to any one of claims 1 to 3, wherein the second head is an eraser head (30) ,

preferably a friction member.

5. A manual device according to any one of claims 1 to 4, comprising at least one actuator member (40) ,

wherein at least one actuator member (40) is configured to actuate the changeover mechanism (50) when pressure is exerted on the actuator member (40) .

6. A manual device according to claim 5, wherein at least one actuator member (40) is provided in a grip zone (P) of the body (10) .

7. A manual device according to claim 5 or claim 6, wherein at least one actuator member (40) comprises:

a pivot portion (41) hinged to the body (40);

a press portion (42) configured to receive pressure from a finger of a user; and

an actuator portion (43) directed towards the inside of the body (10) and configured to actuate the changeover mechanism (50).

8. A manual device according to any one of claims 5 to 7, including two actuator members (40) ,

wherein the two actuator members (40) are situated in half-planes that form between them an angle lying in the range 160° to 200°, and preferably equal to about 180°.

9. A manual device according to any one of claims 1 to 8 , wherein the changeover mechanism (50) comprises a movable carriage (51) secured to one of the first and second heads (20, 30) , the carriage (51) including at least one cam surface (53) configured to co-operate with the actuator member (40) .

10. A manual device according to any one of claims 1 to 9, wherein one of the first and second heads (20, 30) is mounted to move relative to the body (10) and the other one of the first and second heads (20, 30) is stationary relative to the body (10) .

11. A manual device according to any one of claims 1 to 10, wherein the first head (20) is movable, and

wherein the second head (30) is formed by a front end portion (11) of the body (10) , the first head (20) being retracted within the front end portion (11) of the body (10) in the second state.

12. A manual device according to claim 11, wherein the return member (60) is provided at the rear end (lOr) of the body (10) .

13. A manual device according to claim 11 or claim 12, wherein the return member (60) is arranged so as to exert a resilient force on the first head (20) .

14. A manual device according to any one of claims 1 to 10, wherein the second head (130) is movable, and

wherein the second head comprises a sheath (130), the sheath (130) completely surrounding the working portion (121) of the first head (120) in the second state.

15. A manual device according to claim 13, wherein the front end portion (111) of the body (110) is provided with a plurality of resilient tongues (111b) configured to mask the second head (130) in the first state, and to allow the second head (130) to project in the second state .

16. A manual device according to any one of claims 1 to

15, including a protection mechanism configured to mask the first head (20) when the manual device is not in use, the protection mechanism comprising a mechanism for retracting the first head (20) inside the body (10) .