MXPA06007823A - Advancing/retracting mechanism - Google Patents

Abstract

An advancing/retracting mechanism having a pair of cams is disclosed. The advancing/retracting mechanism includes a first cam, a second cam, and a barrel. The first cam includes an angled surface and a shoe, and the second cam includes an angled surface and a slider. The shoe engages with a helical surface in the barrel, and the slider engages with a straight surface in the barrel. The first cam travels a first distance along the longitudinal axis of the barrel from a first to a second state, and the second cam travels a second distance that is greater then the first distance along the longitudinal axis of the barrel from the first to the second state.

Description

ADVANCE / RETRACTION MECHANISM FIELD OF THE INVENTION The present invention relates in general to an advance / retract mechanism and more particularly to an advance / retract mechanism having an output device that travels a greater distance than the input device.

BACKGROUND OF THE INVENTION Advance / retract mechanisms are known in the prior art and have been used effectively in a variety of devices, such as writing utensils, erasers, blades, etc. For example, the advance / retract mechanisms are used in writing utensils, such as pens, in order to advance and retract the writing tip inside and outside the body of the pen. The advance / retraction mechanism in such a device includes a body, an activation button, a spring and a rotating cam. A user activates the advance / retraction mechanism by pressing the activation button inside the body of the pen. The activation button includes a plurality of ribs that engage with a plurality of grooves in the pen body that are oriented parallel to the central axis of the body, thereby restricting the movement activation button within the body of the pen . The activation button also includes a plurality of sharp teeth at one end adapted to engage with the rotating cam. The rotating cam, similarly, includes a plurality of ribs that mate with the plurality of grooves, and a plurality of teeth sharpened at one end are adapted to engage with the sharp teeth on the activation button. The plurality of grooves prevent rotation and allow axial movement of the rotating cam during engagement, when disengaging from the plurality of grooves, the rotary cam is free to move in an axial and rotating manner. The engagement of the sharp teeth in the activation button and the rotating cam causes an impulse for the rotating cam to rotate. More specifically, when the ribs of the activation button and the rotating cam align with the grooves of the body, the sharp teeth on the activation button and the rotating cam misalign, so that the points of the teeth on the button activation are at the top with the sides of the tooth of the rotating cam. Therefore, according to the activation button and therefore, the rotating cam are pressed into the boom body, the activation button and the rotating cam will move axially along the plurality of grooves, during which, The rotating cam has an impulse to align its teeth with those of the activation button. Once the ribs on the rotating cam release the slots in the body, and are free to rotate, the teeth of the rotating cam and the activation button will be realigned, which rotates the rotating cam. Once the rotating cam has rotated (ie, the teeth of the rotating cam and the activation button are aligned), the user will remove the force of the activation button, which will cause the impulse created by the spring to return to the button activation to its original position before its pressure. As the activation button is retracted, the ribs of the rotating cam rotated will abut and rest on a plurality of detent members, which causes the rotating cam to remain in the advanced position. The advance / retraction mechanism of another device includes a hollow body including first and second portions, a slide having a pair of guide posts and a pair of helical grooves located in the first portion. More specifically, the pair of guide posts in the slide engage slidingly with the helical grooves in the first portion, which produces an axial movement of the slide when it is rotated relative to the first portion. The slide is allowed to move axially, but remains fixed to the rotation relative to the second portion. Therefore, during the rotation of the first and second portions one relative to the other, the slide rotates with the second portion and the coupling of the posts with the slots causes the slide to advance and retract depending on the direction of rotation .

BRIEF DESCRIPTION OF THE INVENTION In accordance with one aspect of the invention, an advancing / retracting mechanism is described which includes a first cam having an angled surface, a second cam having an angled surface and a barrel. The first cam includes one of a shoe and a helical surface having an axis of rotation, and the second cam includes one of a second shoe and a surface perpendicular to the axis of rotation. The barrel includes the other of the first shoe and the helical surface and the other of the second shoe and the perpendicular surface, wherein at least a portion of one of the cams is disposed in the barrel, and the first shoe is butted with the helical surface and the second shoe is at the top of the perpendicular surface. The angled surfaces of the first and second cams correspond essentially to the first state, and are at least partially opposite in a second state. The first cam travels a first distance along the longitudinal axis of the barrel from the first to the second state and the second cam travels a second distance that is greater than the first distance from the first state to the second state. According to another aspect of the invention, among others, an advance / retraction mechanism having a first cam, a second cam and a barrel is described. The first cam includes a first end that has a first angled surface and a second end that operatively receives the user's input. The second cam includes a first end having a second angled surface that engages the first angled surface and a second end operatively activating the output device. The barrel includes a helical surface that engages a portion of one of the first and second cams from a first position to a second position, and rotates the cam relative to the other cam. In accordance with another aspect of the invention, among others, there is described a writing implement having a barrel, an input device, and an output device. The barrel includes a first end, a second end and a helical surface. The input device is located near the second end of the barrel and is operatively connected to the first cam. The output device is located near the first end of the barrel, and is operatively connected to the second cam. The first cam travels a first distance along the longitudinal axis of the barrel from a first state to a second state, and the second cam travels a second distance along the longitudinal axis of the barrel that is greater than the first distance.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded isometric view of a modality of an advance / retract mechanism. Figure 2 is an enlarged isometric view of the advance / retract mechanism of Figure 1 in a retracted state, with the barrel partially withdrawn. Figure 3 is an amplified isometric view of the advance / retract mechanism of Figure 1 between the advanced state and the retracted state, with the barrel partially withdrawn.

Figure 4 is an enlarged isometric view of the advancing / retracting mechanism of Figure 1 in an advanced state, with the barrel partially withdrawn. Figure 5 is a cross-sectional view taken along line 4-4 of Figure 4 of the advance / retract mechanism of Figure 1, in the advanced state with the barrel removed. Figure 6 is a cross-sectional view of the advance / retract mechanism similar to Figure 5. Figure 7 is a cross-sectional view of another embodiment of an advancing / retracting mechanism in the advanced state, having an angled surface. without contour, with the barrel removed. Figure 8 is a side view of the barrel of Figure 1. Figure 9 is an exploded isometric view of a writing implement incorporating the advance / retract mechanism of Figure 1.; and Figure 10 is an isometric amplified view of the advance / retract mechanism of Figure 9 in an advanced state, and a locked position, with the barrel partially withdrawn. While the method and device described herein are susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described in detail below. However, it should be understood that it is not intended to limit the invention to the specific forms set forth, on the contrary, the intention is to cover all modifications, alternative constructions and equivalents that fall within the spirit and scope of the invention as defined in the appended claims.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings and with specific reference to Figure 1, an advance / retract mechanism is constructed in accordance with the teachings of the invention, and is generally illustrated, with the reference number 20 . As shown here, the advance / retract mechanism 20 in an exemplary embodiment includes a first cam 22, a second cam 24 and a barrel 26. In an exemplary embodiment, the first cam 22 of the advance / retract mechanism 20, as shown in FIG. best shown in Figures 1 and 5, it has a generally cylindrical body 28 which includes a first angled surface 30, an inlet end 32, a post 34, and at least one shoe 36. The generally cylindrical body 28 has the dimensions for sliding and rotating within a space defined by an interior surface 38 of the barrel 26. The first angled surface 30 is disposed opposite the entrance end 32 of the first cam 22, and defines an angle a with respect to the longitudinal axis of the first cam 22, as shown in Figure 6. The at least one shoe 36 and in this embodiment the pair of shoes 36, depend radially outwardly of the generally cylindrical body 28. As best illustrated in Figures 1 and 2, the shoes 36 include an angular contact surface 40, wherein the contact surface 40 and the first angled surface 30 are confronted in similar directions relative to the longitudinal axis of the first cam 22. The angular contact surfaces 40 are slidably coupled with one or more helically shaped surfaces 42 located in the barrel 26 (Figures 1 and 8). The post 34 is axially dependent on the inlet end 32 of the cam 22. As illustrated in Figure 5, the post 34 may include a first end 44 that is butted and integrated with the inlet end 32, a second end 46 opposite. to the first end 44, and an outer surface 48. The post 34 can be located so that the longitudinal axis of the post 34 can coincide with the longitudinal axis of the upper cam 22. The second cam 24 of the advance / retract mechanism 20, as best illustrated in Figures 1 and 5, has a generally cylindrical body 50 including a second angled surface 52, an outlet end 54, at least one notch 56 and at least one slide or shoe 58. The generally cylindrical body 50 has the dimensions to slide within a space defined by the interior surface 38 of the barrel 26. The second angled surface 52 is disposed opposite the exit end 54 on the second cam 24. The second angled surface 52 of the second cam 24 and the first angled surface 30 of the first cam 22 can have essentially similar angles with respect to the longitudinal axis of the cams 22, 24 (Figure 6). Further, when the advance / retract mechanism 20 is in the retracted position (Figure 2), the surface 52 abuts the surface 30 essentially along its entire area. The slides 58 are radially outwardly dependent on the generally cylindrical body 50 and are slidably coupled with at least one slot 60, and in this exemplary embodiment a pair of slots 60 (Figures 1 and 8), located in the barrel 26. In FIG. this mode, the slides 58 have a generally rectangular shape, but may have another suitable shape for sliding within the slots 60. The at least one notch 56, and in this exemplary embodiment, the pair of notches 56, are located in the exit end 54 of the second cam 24 and are oriented such that the notches 56 open to the exit end 54. The pair of notches 56 are disposed opposite each other in the cam 24. The barrel 26 of the advance / retract mechanism 20, as best shown in Figures 1 and 8, has a generally tubular body 78 that includes helically shaped surfaces 42. located near the first end 77 of the barrel 26, and the pair of slots 60 located near the second end 79 of the barrel 26. The helically shaped surfaces 42, in this exemplary embodiment, are a pair of helical tracks extending from the first end 77 of the barrel 26 to the second end. 79 of the barrel 26. The helical tracks 42, as best shown in Figure 8, are disposed at an angle,, relative to the longitudinal axis of the barrel 26, which allows the sliding engagement of the helical tracks 42 with the angled surfaces 40. of the shoes 36. It is believed that the coupling without continuous connection of the first cam 22 with the inner surface 38 of the barrel 26 can be achieved in this way. The movement of the first cam 22, and more specifically, the shoes 36 along the helical surface 42, rotates the first cam 22 relative to the barrel 26, and causes the linear movement of the first cam 22 towards the second end 79. of the barrel 26. The pair of grooves 60 extends upwardly from the second end 79 of the barrel 26 and is adapted to receive the sliding movement of the slides 58 of the second cam 24. The pair of slots 60 are located opposite each other in the barrel 26 and are oriented parallel to the central axis of the barrel 26. The sliding engagement of the slides 58 with the pair of slots 60, allows the axial movement of the second cam 24 relative to the longitudinal axis of the barrel 26. During the operation, the advance / retract mechanism 20 allows the user to increase the travel of an output device, such as a point of a writing instrument, in relation to the user's input, as can be seen from the observation. Figures 2, 4 and 9 in combination. In the retracted position, the first cam 22 and the second cam 24 abut one another along the first and second matching surfaces 30, 52. More specifically, when the advance / retract mechanism 20 is in the retracted position, the tip 66 of the first angled surface 30 abuts the base 72 of the second cam 24, and the tip 68 of the second angled surface 52 remains butt with the base 70 of the first cam 22 (Figure 5). As the advancing / retracting mechanism 20 advances, as will be recognized when comparing Figures 2, 3 and 4, the user applies force on the first cam 22 to cause a movement of the first cam 22 from X! to X2. The movement from X-i to X2 and the movement from YT to Y2, as will be described later, is indicative of the movement of the first end 28 of the first cam 22 and the second end 54 of the second cam 24, respectively. Concurrently, the angled surfaces 40 of the shoes 36 are slidably coupled with the helically shaped surfaces 42 near the first end 77 of the barrel 26 and the slides 58 of the second cam 24 are slidably coupled with and close to each other. the upper part of the grooves 60. As the user applies an axial force to the inlet end 32 of the first cam 22, as shown in Figure 3, the shoes 36 of the first cam 22 can slide along the lengths of the legs. surfaces 42 in helical form, which causes several portions of the first angled surface 30 of the first cam 22 to be abutted in several portions of the second angled surface 52 of the second cam 24. The second cam 24 may be restricted to movement axial and the first cam 22 can cause both to rotate relative to the barrel 26 and move linearly to the bottom of the barrel 26, until the cams 22, 24 are in the extended position, that is, the first and second mating surfaces 30, 52, only abut near the tips 66, 68 (Figures 4 and 5). As a result of this, the first and second cams 22, 24 will rotate one relative to the other, which causes the output end 54 of the second cam 24 to move a distance from Y-i to Y2, which is greater than the distance X ^ a X2 that the first 22 cam travels (compare Figures 2, 3 and 4). The degree of angle of the first angled surface 30 can be related to the desired amount of travel from the cams 22, 24 during the operation. That is, when the angle a of the first surface 30 angled with respect to the longitudinal axis of the first cam 22 is greater than what the second cam 24 travels a small distance along the longitudinal axis (Figure 6). Similarly, when the angle a of the first surface 30 angled with respect to the longitudinal axis of the first cam 22 is small, then the second cam 24 will travel a longer distance. According to one embodiment, the angle of the first angulated surface 30 with respect to the longitudinal axis may be between thirty and seventy degrees, and more specifically, it may be approximately forty-five degrees. In an exemplary embodiment, as shown in Figure 5, the first and second mating surfaces 30, 52 of the first and second cams 22, 24 respectively, include surfaces 62, 64 of twisted contour. The twisted contour surfaces 62, 64 are carried to provide more than one point of contact between the cams 22, 24 during operation. As best illustrated in Figure 5, it is believed that a line, better than a point, of contact will be reached between the first cam 22 and the second cam 24 as the cams 22, 24 rotate relative to one another. Specifically, when in the extended position, the tips 66, 68 of the twisted contour surfaces 62, 64 will be parallel to each other and essentially perpendicular to the longitudinal axis of the cams 22, 24. Similarly, the bases 70, 72 of the surfaces 62, 64 of twisted contour are parallel to each other and essentially perpendicular to the longitudinal axis of the cams 22, 24. Also, it is believed that by maintaining a contact line it can (i) allow a greater transfer of force between the cams 22 , 24; and (ii) increasing the wear resistance of the cams 22, 24 and / or (iii) increasing the smoothness of the sliding action of the cams 22 and 24 during rotation. In another embodiment of the matching surfaces 30, 52, as best shown in Figure 7, the matching surfaces 30, 52 can be flat, unbent surfaces 74, 76. As the cams 22, 24 rotate relative to one another, a point, better than a line, of contact can exist during the different stages of rotation of the cams 22, 24. For example, when they are in the extended position, the points 66, 68 of the flat surfaces 74, 76 will be oriented at an angle f relative to each other, just as the bases 70, 72 are.

The above exemplary embodiments may include variations thereof to achieve and / or create additional and / or alternative features. For example, the first cam 22 and the second cam 24 may include more or less than two shoes 36 and slides 58. The first cam 22 and the second cam 24 may also have or include other shapes, and more specifically, may include other shapes in cross section relative to the longitudinal axis of the cams 22, 24. For example, the first or second cams 22, 24 can be round, triangular, square, rectangular, oval or any cross-sectional shape, as long as they have the capacity of move in a sliding manner within and in the case of the cam 22, rotate inside another component, such as the barrel 26. Similarly, as before, a portion of the first or second cams 22, 24 may have another shape different from the round or a circular cylinder. The helical surfaces 42 of the barrel 26 can be one or more helical tracks and the barrel 26 can include one or more slots 60. The shoes 36 and the slides 58 of the first and second cams 22, 24 are also not restricted in their previously described form . The shoes 36 and the slides 58, for example, they can be round, triangular, oval or any shape with the ability to slidely engage the helical surfaces 42 and the slots 60 of the barrel 26. The interior of the cams 22, 24 can be solid or hollow, depending of the desired use. For example, when more than one contact area is desired between the surfaces 30 and 52 of the mating surfaces of the first and second cams 22, 24 respectively, then the interior of the cams 22, 24 may be solid. However, when it is desired to have part of a writing instrument extended upwardly through the barrel 26, then the interior of the cams 22, 24 may be hollow to accommodate various parts of the writing instrument. In addition, the barrel 26 may include one or more portions, and the one or more portions of the barrel may be an integrated part of the housing 86. As such, the housing 86 may create a backing portion for the slots 60 disposed in the barrel 26, so that the slots 60 in this mode can be channels. In addition and / or alternatively, the helically shaped surfaces 42 and / or the slots 60 may be located in the barrel 26. The helical surface 42 and the slots 60 are not limited to being defined by the barrel 26, and the slides 58 and the shoes 36 are not limited to being arranged or depending on the first or second cams 22, 24. More specifically, the helical surface 42 can be located on the first cam 22, and the shoes 36 can be part of the barrel 26. Similarly, the slots 60 may be located in the second cam 24, and the slides 58 may be part of the barrel 26. The advance / retraction mechanism 20 will now be described as being used in a writing utensil 82, and more specifically , as used in a fountain pen. The fountain pen, as illustrated in Figure 9, may include advance / retract mechanisms 20, a housing 86, an output device assembly 88, and an input device 84. In this exemplary embodiment, the housing 86 includes a first section 86a and a second section 86b. The housing 86 is generally tubular in shape and includes an opening 100 at the first end 104 of the first second section 86a, and an opening 106 for the output device 88 at the second end 108 of the first section 86b. The housing 86 may also include a radially inwardly extending edge 110 defining a shoulder disposed near the opening 106 of the housing 86 against which a spring 112 is located. The input device 84 has a generally cup-shaped body that has an inner surface 92, a closed end 94 and an annular rim 96 that depends on the open end 98. The input device 84 is operably connected to the first cam 22. More specifically, the outer surface 48 of the post 34 has the measures to rotate within the space defined by the inner surface 92 of the input device 84, so that when the user presses the input device 84, the post 34 and therefore, the first cam 22 can rotate with respect to and within the input device 84, which allows the user to press the input device 84 without feeling the rotation of the device. first cam 22.

The length of the post 34 may be such that in the complete insertion of the post 34 within the input device 84, the second end 46 of the post 34 may abut the closed end 94 of the input device 84. As such, the closed end 94 transfers the force in the post 34 and therefore, to the first cam 22. The length of the post 34, however, can be such that with the full insertion of the post 34 within the device 84 of inlet, the annular flange 96 may abut the inlet end 32 of the first cam 22. Here, the surface area of the flange 96 translates the force at the inlet end 32 of the first cam 22. In addition, the flange 96 The annular can secure the input device 84 within the housing 86. More specifically and as better illustrated in FIG. 9, the input device 84 can have the dimensions and shape to slide and rotate within an area defined by the aperture 100 located at the first end 104 of the housing 86, but the input device 84 may be prevented from falling into the opening 100 because the annular flange 96 is larger than the opening 100. The annular flange 96 may, therefore, q To butt the first end 104 of the housing 86, which secures the input device 84 in the housing 86. Referring now to the mounting 88 of the output device, the assembly 88 may include several individual parts which in combination form the assembly 88 of the output device, as described here. For example, the assembly 88 of the output device may include the writing tip 80 designed to print ink on the receiving surface, such as paper, a well for housing ink, such as the ink cartridge, and an adapter for holding and combining the well. of ink and writing tip 80 together. Also, additional features or parts may be included. In addition, the mounting 88 of the output device may have a generally cylindrical shape and may include, in addition to the writing tip 80, a bank 116 extending radially outwardly, a pair of buttons 120 extending radially outwardly, and an extended post 122. in axial form. The mounting 88 of the output device also includes a first end 114, a second end 124 and a central section 118 therebetween. The writing tip 80 is located at the first end 114, and the edge 116 extended radially outward defines a shoulder that depends on the central section 118. The pair of buttons 120 extended radially outward define an alignment feature that depends on the central section 118. The edge 116 extended radially outward is complemented by the edge 110 extended radially inwardly and adapted to engage the spring 112. More specifically, during operation, the spring 112 is disposed between the two extended edges 110 and 116 and is compressed in the advanced position and compresses less in the retracted position. In other words, the spring 112 provides a pulse in the assembly 88 of the output device toward the retracted state. The pair of buttons 120 extended radially outwardly are disposed opposite one another in the mounting 88 of the output device, and are adapted to be disposed within the notches 56 located in the second cam 24. With the pair of buttons 120 radially extended outwardly disposed in the notches 56, the output device 88 is prevented from rotating relative to the second cam 24. In the retracted state, the writing tip 80, as part of the assembly 88 of the output device of the writing utensil 82 , retracts inside the housing 86. As such, the spring 112 can be compressed a little, which drives the assembly 88 of the output device, the advance / retraction mechanism 20, and / or the output device 84 towards the first end 104 of the housing 86. The urge of the spring 112 will cause the above components to enter a compression state between the first end 104 of the housing 86 and the second end 106 of the housing. 86, which eliminates the unwanted or uninitiated movement of the components within the housing 86 and / or the barrel 26. The spring 112 is disposed between the two extended edges 110 and 116, so that the impulse of the spring 112 forces the assembly 88 of the output device against the second cam 24. More specifically, the pair of buttons 120 radially outwardly will engage with the notches 56 disposed in the second cam 24, which prevents rotation of the output device assembly 88 with respect to to the second cam 24. In addition, the advance / retract mechanism 20 will be in the retracted position, so that the input device 84 extends from the housing 86 through the opening 100. To extend the assembly 88 of the output and more particularly, the write tip 80 of the housing 86, the user activates or presses the input device 84. The force of the input device 84 is transmitted operatively to the first cam 22, which causes the advance / retract mechanism 20 to enter the extended state. The second cam 24, as the notches 56 engage the pair of buttons 120 extended radially outwardly in the output device assembly 88, will transmit the movement of the advance / retract mechanism 20 to the output device assembly 88 and will force the assembly 88 of the output device against the spring impulse 112. Once the spring 112 has been compressed sufficiently between the two extended edges 110 and 116, the writing tip 80 will extend from the housing 86 to an open end 106. The above exemplary embodiment may include several modifications, which creates additional and / or alternative features. For example, the housing 86 may be a unitary structure. However, when the housing 86 is constructed of two or more sections, the housing 86 may include threads or fastening devices to secure the sections together. Similarly, housing 86 may include a grasping or related feature to create a more ergonomic writing implement 82. It is also contemplated that the housing 86 may be part of the barrel 26 or that the housing 86 and the barrel 26 be an integrated unit, which reduces the number of components forming the writing utensil 82. Similarly, the output device 88, the input device 84 and the housing 86 may have a variety of cross-sectional shapes, such as oval, triangular or square. Similarly, the number and placement of the different components may vary and be different. For example, the pair of buttons 120 may actually be one or more buttons 120 and may be located anywhere in the output device 88, or they may not exist. The buttons 120 can be eliminated due to the lack of rotational movement of the second cam 24. More specifically, a functional aspect of the buttons 120 is to restrict the rotational movement of the output device 88. By engaging the buttons 120 with the notches 56 in the second cam, which may also limit the rotational movement due to the engagement of the slides 58 with the slot 60, the output device 88 may not rotate. When the buttons 120 are removed, the output device 88 may undergo rotational movement, due to the lack of rotational movement of the second cam 24. The writing implement 82 may also include a locking mechanism 129 to maintain the tip 80 for extended writing from the housing 86 after the extension of the advance / retract mechanism 20. As seen in Figures 9 and 10, the barrel 26 may include a notch 130 disposed along an edge of the groove 60. In this exemplary embodiment, the groove 130 is disposed near the opening of the groove 60 in the groove 60. second end 79 of the barrel 26. Alternatively, the writing utensil 82 may incorporate other locking mechanisms known in the art. More specifically, with additional and / or alternative components, the writing utensil 82 can be designed to include and / or have additional features. For example, the writing utensil 82 may include additional and / or alternative components for performing a one-click lock and advance and a one-click unlock / retraction / advance mechanism. During the operation, as seen in Figure 10, during the advancement of the advance / retraction mechanism 20 the first cam 22 can rotate in the direction of the arrow A and causes the tendency for the lower cam 24 to rotate in the direction of the arrow B. As the second cam 24 traverses along the slot 60 during the advance, the slide 58 of the second cam 24 will traverse along the edge of the slot 60 towards which the second cam 24 tends to rotate. With the slide 58 having the tendency to rotate, the slider 58 will engage and rotate within the notch 130 once the slider 58 reaches the notch 130. Once the slider 58 engages with the notch 130, the user can removing the pressure from the inlet device 84, which allows the spring impulse 112 to force an upper edge 132 of the slider 58 against the upper edge 134 of the notch 130, which secures or locks the lower cam 24, and thus both, the 80th point of writing in the advanced state. The lower cam 24 and therefore the writing tip 80 can be uncoupled or unlocked from the notch 130 by pushing or rotating the slider 58 relative to the notch 130 and / or the barrel 26. More specifically, the user can manually cause it that the slide 58 rotates or disengages from the notch 130 when pushing or pulling the slider 58 with the tip of a finger or the like thereof, from the notch 130. As such, the housing 86 may include an access opening 136 to allow the access to the slider 58 and / or to the notch 130. Once the slider 58 and the notch 130 are disengaged, the impulse of the spring 112 can cause the second cam 24 and therefore, the writing tip 80 to retract within of the housing 86. Furthermore, the present invention of the advance / retract mechanism 20 is not limited to being used in a writing utensil 82, as described above, rather, it can be used in many other types of devices. For example, the advance / retract mechanism 20 can be used to advance or retract several objects, such as a eraser in a pen-eraser device, a blade in a pen-knife type device, a pencil tip, glue in a bar glue, etc. While the present invention has been described with reference to the specific examples, which are intended to be illustrative and not to limit the invention, it will be evident that those skilled in the art will be able to recognize changes, additions or omissions in the above modalities without departing of the spirit and scope of the invention.

Claims (21)

1. An advance / retraction mechanism, characterized in that it comprises: a first cam including an angled surface and one of a first shoe and a helical surface having an axis of rotation; a second cam including an angled surface and one of a second shoe and a surface perpendicular to the axis of rotation; and a barrel including the other of the first shoe and the helical surface and the other of the second shoe and the perpendicular surface, the first shoe is butted with the helical surface and the second shoe is butted with the perpendicular surface, by at least one portion of one of the cams is disposed in the barrel; wherein the angled surfaces of the first and second cams correspond partially in a first condition, and are at least partially opposed in a second condition, and the first cam travels a first distance along the longitudinal axis of the barrel from the first state to the second state and the second cam travels a second distance that is greater than the first distance from the first state to the second state.

The advancing / retracting mechanism according to claim 1, characterized in that the first cam includes the first shoe for slidably engaging with the helical surface in the barrel.

3. The advance / retraction mechanism according to claim 1, characterized in that the second cam includes the second shoe that engages in a sliding manner with the perpendicular surface in the barrel.

The advancing / retracting mechanism according to claim 1, characterized in that the first and second cams are butted along more than one contact point in the second state.

The advancing / retracting mechanism according to claim 1, characterized in that at least a portion of the angled surface is perpendicular to the longitudinal axis of the cam.

6. The advancing / retracting mechanism according to claim 1, characterized in that the angled surface is non-planar.

An advance / retraction mechanism characterized in that it comprises: a first cam including a first end and a second end, wherein the first end has a first angled surface and the second end operatively receives the user's input; a second cam including a first end and a second end, wherein the first end has a second angled surface that engages the first angled surface, and the second end operatively activates an output device; and a barrel including a helical surface, wherein a portion of one of the first and second cams engages the helical surface of the first to the second position, and rotates the cam relative to the other cam.

The advancing / retracting mechanism according to claim 7, characterized in that the portion of at least one cam is a shoe.

The advancing / retracting mechanism according to claim 7, characterized in that the portion of the at least one cam slidably engages the helical surface of the barrel.

The advancing / retracting mechanism according to claim 7, characterized in that the first and second cams are butted along more than one contact point in a second state.

The advancing / retracting mechanism according to claim 7, characterized in that the first and second cams are abutting along most of the angled surfaces in a first state.

The advancing / retracting mechanism according to claim 7, characterized in that the angled surface of the at least one cam has a first and a second portion that are parallel to each other and perpendicular to the central axis of one of the cams.

A writing implement characterized in that it comprises: a first cam including an angled surface and one of a first shoe and a helical surface having a rotation axis; a second cam including an angled surface and one of a second shoe and a surface parallel to the axis of rotation; a barrel having a first end and a second end, and includes the other of the first shoe and the helical surface and the other of the other shoe and the upper one parallel, the first shoe is butted with the helical surface and the second shoe it is butted with the parallel surface, wherein at least one cam is disposed in the barrel; an input device located near the second end of the barrel, the input device is operatively connected to the first cam, wherein the first cam travels a first distance along the longitudinal axis of the barrel from a first to a second state; and an output device located near the first end of the barrel, the output device is operatively connected to the second cam, wherein the second cam travels a second distance that is greater than the first distance from the first state to the second state .

The writing utensil according to claim 13, characterized in that the input device is a button.

15. The writing utensil according to claim 13, characterized in that the output device is a writing tip.

The writing utensil according to claim 13, characterized in that it comprises a body where the input device and the output device are arranged in a barrel.

17. The writing utensil according to claim 16, characterized in that the body and the barrel are integrated.

18. The writing implement according to claim 13, characterized in that the first cam includes a shoe having an angled contact surface that slidably engages the helical surface of the barrel.

19. The writing implement according to claim 13, characterized in that the second cam includes a slide that slidably engages with the parallel surface in the barrel.

20. The writing utensil according to claim 13, characterized in that the first and second cams are butted along more than one contact point in the second state.

21. The advance / retraction mechanism according to claim 13, characterized in that the angled surface is non-planar.