Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
  • B43K—IMPLEMENTS FOR WRITING OR DRAWING
  • B43K21/00—Propelling pencils
  • B43K21/02—Writing-core feeding mechanisms
  • B43K21/22—Writing-cores gripping means, e.g. chucks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
  • B43K—IMPLEMENTS FOR WRITING OR DRAWING
  • B43K21/00—Propelling pencils
  • B43K21/02—Writing-core feeding mechanisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
  • B43K—IMPLEMENTS FOR WRITING OR DRAWING
  • B43K21/00—Propelling pencils
  • B43K21/02—Writing-core feeding mechanisms
  • B43K21/027—Writing-core feeding mechanisms with sliding tubelike writing-core guide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
  • B43K—IMPLEMENTS FOR WRITING OR DRAWING
  • B43K21/00—Propelling pencils
  • B43K21/02—Writing-core feeding mechanisms
  • B43K21/16—Writing-core feeding mechanisms with stepwise feed of writing-cores

Definitions

• the present invention relates to a mechanical pencil and more particularly to a mechanical pencil comprising a tubular body extending along a longitudinal axis between a rear end and a front end provided with an opening through which a mine is capable of exit, and a lead advance mechanism arranged in the tubular body, which comprises: - a member movable longitudinally and having a bearing surface oriented towards the front; a clamp having a tubular portion connected to the movable member, and a head capable of being clamped on the mine; - A clamping ring movable longitudinally relative to the clamp and the tubular body, which is adapted to cooperate with the head of the clamp; an elastic element having a front end and a rear end in abutment against the bearing surface of the movable member, said elastic element being adapted to urge the clamping ring against the head of the clamp when the advance mechanism is in rest position.
• the body of the mechanical pencil includes an additional elastic means, the rear end of which bears on the body of the mechanical pencil.
• lead and the front end bears on the clamping ring or optionally on a sleeve bearing on the clamping ring, so as to allow a backward movement of the advance mechanism assembly, c ' is to say including the moving part.
• the movable member is a tube which forms a mine reservoir and into which the rear end of the pliers is force fitted.
• this additional elastic means which may consist of a compression spring or an elastically deformable tube portion, increases the number of parts, complicates the assembly of the mechanical pencil and increases the space required in the co- tubular rps to house the entire mechanism, which a. a negative effect on the manufacturing cost.
• the purpose of the present invention is to overcome the drawbacks mentioned above by proposing a mechanical pencil authorizing a retraction of the mine, which has a simplified structure, in particular in order to reduce its manufacturing cost.
• the recoil of the mine must be elastic, so that it returns to the writing position as soon as the user ceases to exert excessive pressure thereon.
• the subject of the present invention is a mechanical pencil of the aforementioned type, characterized in that a bush, movable longitudinally relative to the clamp and to the body, is arranged between the clamping ring and the front end of - The elastic element, in that the clamp is movable longitudinally relative to the movable member over a determined stroke, called the recoil stroke, and in that the body has a front stop adapted to limit the forward movement from the socket.
• this arrangement allows a retreat of the mine without necessarily causing a retreat of the movable member, which has the advantage of not having an effect on the control means of the movable member and in particular not to cause them to move towards the outside of the body, whether it be a push button arranged at the rear end of the body or a side button movable in a radial direction of the body.
• the front stop is formed by a radially inner rim which cooperates with a peripheral portion of the front end of the sleeve;
• the elastic element is a helical compression spring;
• the tubular portion of the clamp has from its rear end first and second radially outer edges, and the front end of the movable member has an opening through which the clamp slides between the first and second edges, said first and second edges being longitudinally spaced to limit this sliding of the clamp to a value equal to the recoil stroke;
• the tubular portion of the clamp has a frustoconical portion extending from the first flange to the rear end of the clamp, to allow mounting of the clamp by snap-fastening in the movable member.
• the body has a rear stop adapted to cooperate with a complementary stop of the movable member and limit the rearward movement of the member movable, the longitudinal distance between the front stop of the body and said rear stop being adapted so that the clamping ring keeps the clamp tight under the action of the sleeve when the advance mechanism is in the rest position;
• the rear stop is formed by a radially inner rim of the body, which cooperates with a radially outer shoulder of the movable member.
• the body has a window extending longitudinally to a rear end, and the movable member has a lug protruding into the window, the rear end of said window forming the rear stop; at least one elastically deformable compensation member is arranged between the front stop of the body and the sleeve, or between the rear stop of the body and the complementary stop of the movable member, in order to compensate for any play between the advance mechanism and the body stops;
• the compensating member comprises at least one elastically deformable tab in a longitudinal direction and integral with the body;
• the body has a recoil position adapted to limit the displacement of the clamping bar towards the rear, from the rest position of the advance mechanism, to a value at most equal to the recoil stroke of the pliers, so as to increase the tightening of the pliers and to prevent the mine from sliding;
• the back-up stop is formed by at least one pin integral with the body and extending radially inwards between the sleeve and the movable member, said
• FIG. 1 is a view in longitudinal section of a door -mine according to a first embodiment of the invention and in which a mine advance mechanism is in the rest position;
• Figure 2 is an enlarged view of a front portion of the mechanical pencil shown in Figure 1;
• FIG. 4 is a view similar to FIG. 2, in which the advance mechanism has made a second stroke towards the front;
• Figure 5 is a view similar to Figure 2, in which-, the advance mechanism has made a backward stroke 1 rearward;
• Figure 6 enlarged in perspective of an element of the mechanical pencil shown in Figure 1;
• - Figure 7 is a partial view of a half longitudinal section of a mechanical pencil according to, a second embodiment of the invention and in which the advance mechanism is in the rest position;
• Figure 8 is a view similar to Figure 7, in which the advance mechanism has made a back stroke.
• the same references have been kept to designate identical or similar elements.
• Figures 1 to 5 is shown a first embodiment of a mechanical pencil.
• the mechanical pencil 1 comprises a tubular body 2 which extends along a longitudinal axis X between a front end 2a and a rear end 2b.
• the body 2 is formed of a tube 3 and a tip 4 arranged at the front end of the body 2.
• the tip 4 has at its front end an opening through which a lead guide tip 5 which is freely mounted sliding in a bore 4a of the tip 4.
• the guide tip 5 accompanies the exit of the mine 6 to avoid breakage of the mine.
• the wear of the lead reaches the end of the guide tip, the latter touches the paper and makes a backward movement, which releases the end of the lead and allows writing to continue.
• a side button 7 is mounted through a rectangular window 8 formed in the radial wall of the tubular body 2 and extending along the longitudinal axis X.
• the side button 7 has an actuation surface 9 oriented radially towards the outside.
• the side button 7 comprises a first pair of cams 11 arranged opposite the face of one actuator 9 to the front end of the side button having a cross section U.
• the rear end 7b of the side switch section transverse, also in U, has a second pair of cams 12, analogously to one front end. It will be noted that the first pair of cams 11 is spaced from the second pair of cams 12 by a significant distance measured along the axis X, which is close to the longitudinal length of the actuation face 9 of the side button 7.
• the part of the side button 7 located inside the body 2 comprises lugs, and in particular a lug 16 which projects towards the rear end 2b of the body 2, which cooperate with the inner periphery of the window 8 and thus prevent the exit complete with the side button 7 of the tubular body 2.
• a feed mechanism which comprises a movable member 20, a clamp 30, a bush 40, a clamping ring 18 and a compression spring 19 disposed between the movable member 20 and the sleeve 40.
• the rear end 20b of the mobile organ is equipped with an element 46 projecting through the rear end 2b of the body.
• the element 46 comprises a tubular part, a clip and a cylindrical recess in which is mounted an eraser 47.
• the element 46 and the eraser 47 form a rear button which makes it possible to move the movable member 20 forward.
• L movable member 20 is slidably mounted along the longitudinal axis X in the tubular body 2.
• the movable member 20 comprises a front part 21 which forms the front end 20a of the movable member and a main part 22 fixed to the front part 21.
• the main part 22 comprises a first portion located on the side of the front end 20a of the movable member, which will be detailed below, and a hollow rear portion 22b which forms a reservoir of mines. But it is perfectly possible that the mine reservoir is formed by an independent piece fixed to the movable member 20.
• the front piece 21 of the movable member has a recess oriented towards the front end 2a of the body, the bottom 21a of which forms a bearing surface for the spring 19.
• the portion front of the main part 22 of the movable member 20 has a first pair of identical ramps 23 arranged on the side of the front end 20a of the movable member.
• the first ramps 23 are located on either side of a central duct 24 allowing the passage of the mines from the reservoir 22b towards the clamp 30.
• Each first ramp 23 has a rectilinear surface inclined relative to the longitudinal axis X, oriented towards the rear of the body 2.
• the first pair of cams 11 cooperates with the first pair of ramps 23 and causes a displacement towards the front end 2a of the movable member 20.
• a bearing 25 parallel to the longitudinal axis X is formed on the face of the movable member 20 opposite the side button 7. The bearing 25 s 'extends on either side of the conduit 24 and is positioned longitudinally so that the second pair of cams 12 of the side button 7 can bear on the latter when the side button is in the rest position.
• a second pair of ramps 26 immediately follows the rear end of the bearing 25. The second ramps 26 are located on either side of the mine tank and are inclined relative to the longitudinal axis in a manner similar to the first ramps 23.
• the second ramps 26 are spaced longitudinally of the first ramps 23 so that the second pair of cams 12 faces the second ramps 26 when the side button 7 has performed a first tilting movement and is in the position shown in FIG. 3.
• the body 2 of the mechanical pencil has a flange 27 which extends radially inwards and has a surface 27b parallel to the longitudinal axis X in look from window 8 of the body, against which a protruding boss
• the front end of the rim 27 has a transverse surface 27a oriented towards the front which forms a stop, known as the rear stop, against which a radially external shoulder 29 of the movable member abuts.
• the rear stop 27a thus makes it possible to limit the recoil of the movable member 20.
• the clamp 30 comprises a tubular portion 31 and a head 32 which cooperates in known manner with the clamping ring 18 to immobilize the mine 6. In the modes of embodiment shown, the tubular portion 31 extends from a rear end 31b to the head 32 located on the side of the front end
• the tubular portion 31 has from its rear end 31b a first flange 33 projecting outwards in a radial direction perpendicular to the longitudinal axis X, and a second flange 34 also radially exterior.
• the tubular portion 31 of the clamp has a frustoconical portion 35 extending from the first flange
• the clamp can be mounted through the opening 21c of the movable member 20 by snap-fastening.
• the front end of the movable member 20, formed by the front part 21, has an opening 21c through which the tubular portion 31 of the clamp is slidably mounted along the longitudinal axis X between the first flange 33 and the second flange 34.
• the first 33 and second 34 flanges are spaced apart longitudinally so as to allow longitudinal sliding of the clamp 30 by relative to the movable member 20 over a determined length hereinafter called "recoil stroke".
• the sleeve 40 is slidably mounted in the body 2 of the mechanical pencil and it is also movable longitudinally relative to the clamp 30.
• the sleeve 40 is a cylindrical piece which has a central opening 41 through which passes the tubular portion 31 of the clamp, a front end face 42 and a rear end face 43 of planar annular shape.
• the socket 40 could have a different shape, such as for example a cup shape.
• the front annular face 42 of the sleeve extends over a radial distance sufficient to come to bear both against the clamping ring 18 and against a radially internal rim of the body 2 which is formed by the rear end 4b of the tip 4.
• the rear end 4b of the tip thus forms a stop integral with the body 2, called the front stop, which limits the displacement of the bush 40 towards the front end 2a of the body when the peripheral portion of the end before 43 of the ring comes into contact.
• the spring 19 has a front end 19a bearing against the rear face 43 of the bushing and a rear end 19b bearing against the bearing surface 21a of the movable member, so that the spring keeps the bushing as far apart as possible 40 of the movable member 20. It will be noted that the distance between these two parts is limited by the clamp 30 whose first flange 33 cooperates with the opening 21c of the movable member, and the head 32 of which limits the forward movement of the ring 18, which itself limits the forward movement of the bush 40.
• the advance mechanism forms thus a unitary assembly which can be pre-assembled before its introduction into the body 2 of the mechanical pencil by the front end of the tube 3, which facilitates the assembly of the mechanical pencil. It is preferable that the front stop 4b and the rear stop 27a of the body 2 be sufficiently spaced to allow maximum distance between the bush 40 and the movable member 20 when the advance mechanism is in the rest position. In fact, if the distance between the front 4b and rear 21a stops is not sufficient, the bush 40 cannot push the ring 18 on the head 32 sufficiently advanced to guarantee maximum clamping of the clamp head on the lead 6.
• the front stops 4b and rear 21a are spaced so that the advance mechanism is mounted with a slight longitudinal play in the body 2.
• such play can have a negative effect on the quality of the mechanical pencil perceived by the user, since a clicking noise can be caused by the movement of the advance mechanism. in body 2 when the user shakes the mechanical pencil.
• the compensation member 50 is arranged between the front stop 4b of the body and the sleeve 40, but it is clear that the compensation member could be arranged between the rear stop 27a of the body and the complementary stop 29 of the movable member.
• the compensating member 50 is formed by two legs 51 in an arc which can be elastically deformed towards the front end 2a. The ends of the legs 51 are integral with the tip 4, so that the legs 51 form only one piece obtained by molding with the tip 4. But of course, the compensation member 50 could be formed by an independent piece , such as a very short compression spring.
• the tube 3 forming the body of the mechanical pencil comprises two diametrically opposite pins 52, which extend radially inside the body 2 between the sleeve 40 and the movable member 20.
• the pins 52 are arranged at a distance, measured from the rear face 43 of the sleeve in the rest position, which is equal to or slightly less than the recoil stroke of the clamp 30 relative to the movable member 20.
• the spring 19 is a helical compression spring made of metal. This type of spring has the advantage of being able to be compressed over a large stroke while maintaining a constant stiffness. In addition, it is a standard part produced in large quantities and whose stiffness is perfectly known and constant.
• the spring 19 will also be chosen as a function of the dimensions of the advance mechanism, and in particular of the recoil stroke, so as to exert a pressure of between 5 and 10 newtons, and preferably 8 newtons, when the clamp has moved backward equal to the effective mine recoil stroke.
• the operation of the mechanical pencil described above will be explained using FIGS. 2 to 5.
• the clamping ring 18 maintains the head 32 of the pliers tightened on the lead 6 thanks to the action of the spring 19.
• the spring 19 exerts, on the one hand, a rearward pull on the clamp, through the opening 21c of the movable member which is in support against the first flange 33 of the clamp, and on the other hand, a push forward on the clamping ring 18, via the sleeve 40.
• the lead 6 In the rest position, that is to say say outside of any actuation of the side button 7 or rear button formed by the element 46 and the rubber 47, the lead 6 is therefore kept blocked in the head 32 of the pliers.
• a first forward movement of the movable member 20 is obtained to a position shown in FIG. 3, by cooperation of the first pair of cams 11 of the button on the first pair of ramps 23 of the movable member, the second pair of cams 12 remaining supported on the bearing 25.
• this first movement one can distinguish two races of the movable member.
• a first stroke of approximately 2 mm during which the opening 21c of the movable member slides along the tubular portion of the clamp from the first flange 33 to the second flange 34, the clamp 30 remaining stationary during this first race.
• a second stroke called the advance stroke, during which the opening 21c of the movable member is in abutment against the second flange 34 and the clamp 30 moves forward.
• this second stroke the clamping ring 18 accompanies the movement of the head 32 of the pliers and consequently the mine is displaced by a corresponding value.
• the guide tip 5 remains stationary in the bore 4a of the tip, due to a friction force between the guide tip-mine 5 and the tip 4 greater than the friction force between the guide tip 5 and the lead 6.
• this advance stroke is substantially equal to one millimeter, that is to say approximately half of the reverse stroke.
• the head 32 of the pliers comes to bear against the rear end of the guide tip 5, which causes the output of the latter accompanied by the mine 6.
• the latter advances with the mine guide tip 5 due to the friction force existing between the mine guide tip and the mine.
• the spring 19 pushes the movable member 20 backwards, which results in a return of the side button to the position due to the action of the first 23 and second 26 pairs of ramps on the first 11 and second 12 pairs of cams.
• the clamp 30 also performs a movement towards the rear, but the head 32 remains open over almost the entire length of this movement and the lead 6 makes almost no movement. backward movement, so that the guide tip 5 remains in the extended position.
• the entire advancing mechanism returns to the rest position, as shown in FIG. 2, and the head 32 of the pliers again immobilizes the mine 6, but the mine and the guide tip 5 remains out as shown in Figure 4, so that the mechanical pencil is ready to be used.
• the advance of the mine described above is obtained by actuating the side button 7, but of course, actuation of the rear button would cause a similar advance of the mine.
• the effective recoil stroke of the mine is equal to the recoil stroke of the clamp relative to the movable member, but the clamping force of the clamp on the mine does not increase more when the second rim 34 abuts against the opening 21c of the movable member.
• the effective recoil of the mine is preferably limited to a value slightly less than the recoil stroke.
• the clamping force of the head 32 of the pliers on the mine increases significantly because the ring 18 is then immobilized. This avoids the mine sliding in the head 32 of the pliers.
• FIGs 7 and 8 there is shown a second embodiment of a mechanical pencil according to the invention.
• the tubular body 2 is also formed of a tube 3 and a tip 4, however, the tip 4 does not have a guide tip.
• the advance mechanism comprises, as for the first embodiment, a movable member 20, a clamp 30, a clamping ring 18, a bush 40 and a spring 19.
• the advance mechanism is controlled only by a rear button not shown in Figures 7 and 8.
• the movable member 20 is formed of a single front piece 21 which has a frustoconical bearing face 21a, but generally oriented towards the front, and against which is supported on the rear end 19b of the spring.
• the part 21 of the movable member has at its front end 20a an opening 21c through which is movably mounted a clamp 30 quite similar to the clamp of the first embodiment, so that the tubular portion 31 of the clamp slides in the opening 21c between a first flange 33 and a second flange 34 on a determined stroke called 'recoil'.
• the movable member 20 has a lug 53 which projects outwards in a window 54 extending longitudinally in the tube 3 between a front end 54a and a rear end 54b.
• the rear end 54b of the window 54 forms a rear stop of the body which cooperates with a stop complementary to the movable member formed by the lug 53, so as to limit the rearward movement of the movable member 20.
• the sleeve 40 is formed of a slightly conical washer whose movement towards the front is limited by a stop 3a formed by a radially internal rim of the tube 3, which has a first face 55 generally oriented towards the rear of the body.
• the clamping sleeve 18 of this second embodiment has a radially outer shoulder 18a and the radially inner rim 3a of the tube has a face 56 oriented towards the front end 2a of the body.
• the face 56 forms a recoil stop adapted to limit the backward recoil of the clamping ring 18.
• the rear stop 54b and the front stop 55 of the body 2 must be sufficiently spaced longitudinally , so that the advance mechanism firmly immobilizes the lead 6 when it is in the rest position shown in FIG. 7, that is to say that the sleeve 40 must push the clamping ring 18 sufficiently towards the before so that the head 32 of the pliers grips the mine.
• the advance of the pencil 6 is controlled by pressing the rear button of the mechanical pencil, which causes the movable member 20 to move forwards, during which the opening 21c abuts against the second edge 34 of the pliers, then causes the pliers to move forward until the clamping ring 18 abuts against a rim 4c of the point and causes the head 32 of the pliers to open.
• the retraction of the clamp in the open position is then ensured by the spring 19.
• the advance of the mine in this second embodiment, is therefore quite similar to that of the first mode, although the tip 4 does not include advanced mine guide.
• the clamp 30 moves backwards by sliding in the opening 21c of the movable member and compressing the spring 19.
• the movable member 20 remains abutted against the rear stop 54b of the body.
• the shoulder 18a of the ring comes against the recoil stop 56 of the body, which increases the tightening of the ring 18 on the head of the pliers 32 and This makes it very difficult for the lead 6 to slide in the head 32.
• the second rim 34 of the clamp is not in contact with the opening 21c of the movable member when the clamp is in the maximum recoil position. Therefore, for 'this embodiment, the effective stroke of reversing the lead 6 is smaller than the backward stroke of the gripper 30 relative to the movable member.

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• Mechanical Pencils And Projecting And Retracting Systems Therefor, And Multi-System Writing Instruments (AREA)

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• 2003
  • 2003-10-22 FR FR0312333A patent/FR2861331B1/fr not_active Expired - Fee Related
• 2004
  • 2004-10-18 EP EP04817287A patent/EP1675732A1/fr not_active Withdrawn
  • 2004-10-18 WO PCT/FR2004/002659 patent/WO2005039889A1/fr active Search and Examination
  • 2004-10-18 US US10/577,007 patent/US20070134046A1/en not_active Abandoned
  • 2004-10-18 MX MXPA06004495A patent/MXPA06004495A/es unknown
  • 2004-10-18 AU AU2004283918A patent/AU2004283918A1/en not_active Abandoned
  • 2004-10-18 CN CNB200480031327XA patent/CN100503270C/zh not_active Expired - Fee Related
  • 2004-10-18 BR BRPI0415642-0A patent/BRPI0415642A/pt not_active IP Right Cessation
  • 2004-10-18 CA CA002542879A patent/CA2542879A1/fr not_active Abandoned
  • 2004-10-20 TW TW093131764A patent/TW200523135A/zh unknown

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