US3728033A - Push-type mechanical pencil with improved lead advancing means - Google Patents

Push-type mechanical pencil with improved lead advancing means Download PDF

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Publication number
US3728033A
US3728033A US00140144A US3728033DA US3728033A US 3728033 A US3728033 A US 3728033A US 00140144 A US00140144 A US 00140144A US 3728033D A US3728033D A US 3728033DA US 3728033 A US3728033 A US 3728033A
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US
United States
Prior art keywords
writing unit
barrel
recess
spring
engaging member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00140144A
Other languages
English (en)
Inventor
S Seta
T Naruse
M Ikawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dai Nihon Bungu Co Ltd
Japan Stationery Co Ltd
Original Assignee
Dai Nihon Bungu Co Ltd
Japan Stationery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP4403470U external-priority patent/JPS4934197Y1/ja
Priority claimed from JP4334570A external-priority patent/JPS5516839B1/ja
Application filed by Dai Nihon Bungu Co Ltd, Japan Stationery Co Ltd filed Critical Dai Nihon Bungu Co Ltd
Application granted granted Critical
Publication of US3728033A publication Critical patent/US3728033A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • B43K21/16—Writing-core feeding mechanisms with stepwise feed of writing-cores

Definitions

  • a barrel for a push-type mechanical pencil is provided with a large recess and a small recess, with both [21 Appl. No.: 140,144 recesses being defined by a common shoulder.
  • a s1idable writing unit within the barrel has an engaging member attached thereto and is contained in the small [30] Forelgn Apphcanon Pnonty Data recess, at its retracted position, by a spring.
  • a cylindrical member having a protrusion is turnably mounted on the writing (pen) unit or a pushing rod projected beyond the rear end of a barrel.
  • the cylindrical member is turned (rotated) for a certain angle as its protrusion is thrusted against inclined guide surfaces provided at the inside of the barrel.
  • the cylindrical member is straightly retracted and is engaged alternatively with each of short or long grooves also provided at the inside of the barrel, whereby the tip portion of the writing unit is projected and retracted from the barrel. It has been difficult to manufacture such mechanical pencils because the inside surface of the barrel has to be accurately provided with short and long grooves and with inclined guide surfaces to turn the cylindrical member.
  • a slider at the front end thereof supports and protects a lead projected for a relatively long length beyond the tip of the pencil.
  • the slider gradually retracts as it is pressed at the surface of paper.
  • the mechanical pencil having the slider has the advantage that the lead can be beforehand projected from the tip of the pencil for a relatively long length.
  • a push-type mechanical pencil in accordance with the present invention includes a writing unit within a barrel.
  • This writing unit is movable along the axial direction of the barrel and is always urged backwardly by a first spring.
  • a pushing force is applied to the writing unit against the first spring, it advances (forward) and thereby pushes an annular guide member which is provided around an inner large recess of the barrel to be movable therein.
  • An engaging member is attached to the writing unit. This engaging member has an end portion which is, at the starting position, contained in a small recess in the barrel and tends to extend outwardly.
  • the engaging member also advances and, as soon as the end portion thereof passes the rear shoulder of the large recess, it inclines outwardly due to its own force, or component force of the pushing force, and engages with the shoulder of the large recess. In this position the backward movement of the writing unit is prevented and the writing position is attained.
  • the writing unit can be advanced further than the writing position.
  • the engaging member frictionally engages into the annular guide member since the annular member abuts with a front shoulder of the large recess and does not advance any longer.
  • the engaging member retracts backward, together with the annular guide member, along the same way that it passed before and returns to the starting position by leaving the annular guide member to the rear shoulder of the large recess.
  • a cylindrical member is concentrically provided in its barrel and outside of the writing unit.
  • a front marginal portion of the cylindrical member grips a chuck provided at the end of the writing unit relatively firmly and holds a lead securely when the writing unit is urged backward by the compression of the first spring.
  • the cylindrical member is also advanced together with it.
  • a second spring under compression is provided in front of the large recess in the barrel. This second spring does not work at all while the writing unit is advanced to the writing position.
  • the second spring is compressible only after the writing unit further advances from the writing position and an enlarged rear portion of the cylindrical member contacts with the end of the second spring.
  • the force required to compress the second spring normally exceeds the gripping force between the cylindrical member and the chuck, the cylindrical member is left in position and only the writing unit is advanced forward to push the slider by its front chuck.
  • the second spring is compressed when the engaging member attached to the writing unit comes to push the enlarged end portion of the cylindrical member.
  • the head portion of the chuck further pushes the slider as much as the spring is compressed.
  • the chuck frictionally engages the front end of the cylindrical member which front end is in turn engaged with the rear end of the slider, thereby retracting the slider in the barrel.
  • FIG. 1A is a side view of a mechanical pencil according to an embodiment of the present invention, the upper half of which is cross sectioned;
  • FIGS. 1B to IE are cross-sectional views of the same mechanical pencil as in FIG. 1A, each of which illustrates different positions of movable members;
  • FIGS. 2A to 2D are cross-sectional views explanatorily showing the pushing device adapted to FIGS. lA-lC, each of which illustrates different movements of the pushing device;
  • FIGS. 3A to 3D are cross-sectional views showing another pushing device according to a second embodiment of the present invention, each of which illustrates different movement of the pushing device;
  • FIGS. 4 to 7 are cross-sectional views showing pushing devices according to other embodiments of the present invention.
  • an elongated barrel 10 comprises an intermediate cylindrical body 11, a front cylindrical body 12, a back cylindrical extension 13, a part of which is tapered, and an annular ring-like member 14.
  • the front body 12 is threaded to the intermediate cylindrical body 11.
  • a recess 18 of larger diameter and a recess 19 of smaller diameter are provided in the interior of the intermediate cylindrical body 11, said large and small recess being defined by a shoulder.
  • a cylindrical member 20 having an annular integral outwardly extending stopper 21, formed of an enlarged rear end, and an outwardly extending flange 22 at its front outward end is contained in the interior of the intermediate cylindrical body 1 1.
  • a slider 23, to support the lead is slidably mounted to advance from and retract into an orifice of the front cylindrical body 12.
  • the slider 23 is provided with an inwardly directed flange 24 at its rear end to engage with the flange 22 of the cylindrical member 20.
  • the reference numeral 25 designates an annular rubber member which serves to hold the lead while a chuck 33 is open.
  • the writing or pen unit is an inner casing comprising a tubular lead tank 31 with a connector 32 fixed on its end and a chuck 33 screwed to the connector 32.
  • a cap 35 is removably mounted on the rear open end of the lead tank 31.
  • a first spring is interposed between the end surface 17 of the intermediate cylindrical body 11 and an annular spring receiving member 41 which engages with a protruding portion 36 formed near the rear open end of the lead tank 31.
  • a second spring 42 is interposed between a shoulder 15 of the front cylindrical body 12 and the front end of the annular ring member 14 by means of annular spring receiving members 43 and 44.
  • An engaging member 50 is fixed on the writing unit 30.
  • This engaging member 50 has a flexible arm 51 which always tends to extend outwardly and the reference numeral 52 designates its rear end portion.
  • An annular guide member 53 is slidably mounted around the recess 18, i.e., it is able to slide axially. The inner surface of guide member 53 frictionally engages with the engaging member 50, as disclosed hereinafter.
  • the cylindrical member 20 begins to move due to the frictional engagement with the chuck 33 and the first spring 40 is gradually compressed.
  • the second spring 42 is not yet influenced.
  • the annular guide member 53 is pushed to move forward. If the writing unit 30 advances still further (even after the further slide of the guide member 53 is prevented by the end surface of the annular member 14 or of the shoulder of the recess 18) the engaging member 50 is forced to enter into the guide member 53 and the end portion 52 of the engaging member 50 is compressed (see FIGS. 1C and 2C).
  • the lead While the engaging member 50 is in the position as shown in FIG. 2B, the lead is advanced by the wellknown chuck device.
  • the second spring 42 When it is desired to retract the writing unit 30 to the starting position in the small recess 19, the second spring 42 is compressed enough for the engaging member 50 to firmly engage with the annular guide member 53 and then the pushing force is removed (see FIG. 1C and FIG. 2C).
  • the annular guide member 53 is retracted together with the engaging member 50 by the reaction of the first compressed spring 40, and after the rear end of the guide member 53 stops at the rear shoulder of the recess 18 (see FIG. 20), the compressed engaging member 50 slides back into the smaller recess 19, also by the reaction of the first spring 40, and returns to the starting position as shown in FIG. 2A.
  • FIG. 1E illustrates a stage in-which the slider 23, which retracts as the lead is worn out by writing, is in the most retracted position, wherein the slider 23 stops at the flange 22.
  • the arm 51 faces rearward in the embodiment above, another arm as shown in FIG. 4 may be employed in place of the former arm 51.
  • the arm 60 faces to the front and is provided with a hook 61 for engagement at its free end.
  • a structure is considered in which a curved spring board 62 fixed at its one end to the writing unit 30 is provided with a projection 63 at its other free end as shown in FIG. 5, or another alternative is a structure with a protrusion 64 which is always urged outward by a spring 65 or 66 shown in FIG. 6 or FIG. 7.
  • the engaging member can be replaced by one which is not flexible.
  • One of the embodiments using such a member is as follows. Instead of the flexible engaging member, a connecting member 56 is provided between the writing unit 30, of about half length of the writing unit shown in FIGS. 1A to IC, and a pushing rod 55 having a head 54 which engages with the rear shoulder of the small recess 19.
  • This connecting member 56 has an outer surface'57 which operates like a wedge and engages relatively firmly with the inner surface of the annular guide member 53.
  • the member 56 also has a tapered pressure receiving surface 58 which is pressed by the head 54 of the pushing rod 55, and has a seat 59 which is freely inclined at the end of the writing unit 30 as the pushing force is applied to the tapered surface 58 by the pushing rod 55.
  • the seat 59 may be a cone pivot type as shown in the drawing, a knife-edge, a pin-joint type or any other shape that permits the pivotal movement at the end of the pen unit.
  • the rear end of the connecting member 56 stops at the shoulder of the smaller recess 19 and the pen unit 30 is in its retracted starting position.
  • the pushing rod 55 is pushed forward, the rear end of the connecting member 56 enters into the large recess 18 and then the connecting member 56 inclines outwardly since it is pivotally connected with the end of the writing unit 30 and the tapered surface 58 receives the pushing force.
  • the pushing force is removed, in this position, the rear end of the connecting member 56 is pushed backward by the spring and stops at the shoulder of the larger recess 18; that is, the writing unit 30 is placed in the writing position (see FIG. 3B).
  • a push-type mechanical pencil with lead advancing means comprising:
  • an elongated barrel having therein a recess of larger diameter and a recess of smaller diameter, said large and small recesses being defined by a shoulder;
  • a writing unit provided within said barrel and slidable along the axial direction thereof, said writing unit being urged rearward by a spring;
  • said engaging member when said engaging member is given a pushing force to pass the small recess, it inclines outwardly to be stopped at said shoulder at a writing position, and when said engaging member is engaged with the inner surface of said annular guide member by advancing said writing unit furthermore and then the pushing fdrce is removed, said engaging member smoothly returns to the first starting position without engaging with said shoulder, said retracting path of the engaging member being the same as the advancing path thereof.
  • said engaging member comprises a pushing rod and a connecting member, said pushing rod having an inclined head portion to contact with said connecting member and a stem extending backward therefrom, said connecting member having an inclined surface to receive a pushing force through said pushing rod and a connecting means able to pivotally incline at the rear end of said writing unit by a component of the pushing force applied to said inclined surface with said pushing rod.
  • a push-type mechanical pencil comprising:
  • a barrel provided in its inner wall with a recess of larger diameter and a recess of smaller diameter, said large and small recesses being defined by a shoulder;
  • a writing unit provided within said barrel and adapted to be slidable along its axial direction, said writing unit having a chuck means and being urged rearward by a first spring;
  • said second spring is compressible by an outwardly extending flange of said cylindrical member when the latter is advanced from said second position and said second spring is compressed by the succeeding advancement of sai cylindrical member.

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  • Mechanical Pencils And Projecting And Retracting Systems Therefor, And Multi-System Writing Instruments (AREA)
US00140144A 1970-05-06 1971-05-04 Push-type mechanical pencil with improved lead advancing means Expired - Lifetime US3728033A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP4403470U JPS4934197Y1 (enrdf_load_stackoverflow) 1970-05-06 1970-05-06
JP4403370 1970-05-06
JP4334570A JPS5516839B1 (enrdf_load_stackoverflow) 1970-05-22 1970-05-22

Publications (1)

Publication Number Publication Date
US3728033A true US3728033A (en) 1973-04-17

Family

ID=27291508

Family Applications (1)

Application Number Title Priority Date Filing Date
US00140144A Expired - Lifetime US3728033A (en) 1970-05-06 1971-05-04 Push-type mechanical pencil with improved lead advancing means

Country Status (4)

Country Link
US (1) US3728033A (enrdf_load_stackoverflow)
DE (1) DE2122047C3 (enrdf_load_stackoverflow)
FR (1) FR2091167A5 (enrdf_load_stackoverflow)
GB (1) GB1336754A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3813175A (en) * 1971-12-04 1974-05-28 Faber Castell A W Mechanical pencil
US4218153A (en) * 1978-04-01 1980-08-19 Ancos Co., Ltd. Mechanical pencil
US4382706A (en) * 1980-05-07 1983-05-10 Ancos Co., Ltd. Mechanical pencil

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2222295A (en) * 1939-01-19 1940-11-19 Spencerian Pen Company Mechanical pencil
CH274269A (de) * 1949-04-08 1951-03-31 Ag Brac Druckfüllbleistift.
US2700959A (en) * 1951-08-20 1955-02-01 Rodi & Wienerberger Ag Mechanical pencil
US3537799A (en) * 1967-12-20 1970-11-03 Fumiko Sakamoto Mechanical pencil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2222295A (en) * 1939-01-19 1940-11-19 Spencerian Pen Company Mechanical pencil
CH274269A (de) * 1949-04-08 1951-03-31 Ag Brac Druckfüllbleistift.
US2700959A (en) * 1951-08-20 1955-02-01 Rodi & Wienerberger Ag Mechanical pencil
US3537799A (en) * 1967-12-20 1970-11-03 Fumiko Sakamoto Mechanical pencil

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3813175A (en) * 1971-12-04 1974-05-28 Faber Castell A W Mechanical pencil
US4218153A (en) * 1978-04-01 1980-08-19 Ancos Co., Ltd. Mechanical pencil
US4382706A (en) * 1980-05-07 1983-05-10 Ancos Co., Ltd. Mechanical pencil

Also Published As

Publication number Publication date
GB1336754A (en) 1973-11-07
DE2122047B2 (de) 1973-12-20
DE2122047C3 (de) 1974-07-18
DE2122047A1 (de) 1971-11-18
FR2091167A5 (enrdf_load_stackoverflow) 1972-01-14

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