CA1219555A - Mechanical pencil - Google Patents
Mechanical pencilInfo
- Publication number
- CA1219555A CA1219555A CA000471881A CA471881A CA1219555A CA 1219555 A CA1219555 A CA 1219555A CA 000471881 A CA000471881 A CA 000471881A CA 471881 A CA471881 A CA 471881A CA 1219555 A CA1219555 A CA 1219555A
- Authority
- CA
- Canada
- Prior art keywords
- lead
- advance
- grooves
- spaced apart
- retract mechanism
- 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
Links
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
- B43K21/08—Writing-core feeding mechanisms with the writing-cores fed by screws
Landscapes
- Mechanical Pencils And Projecting And Retracting Systems Therefor, And Multi-System Writing Instruments (AREA)
Abstract
MECHANICAL PENCIL
ABSTRACT OF THE DISCLOSURE
A low-cost mechanical pencil employing an improved lead-driving mechanism in which there is cooperation between a low-cost, helical spring member through which moves a lead advance-retract member which is keyed to longitudinal grooves in the inner barrel wall.
If the lead is subjected to excessive pressure during use, it is caused to partially retract into the tip by virtue of axial compression of the helical spring, thereby reducing the likelihood of lead breakage.
ABSTRACT OF THE DISCLOSURE
A low-cost mechanical pencil employing an improved lead-driving mechanism in which there is cooperation between a low-cost, helical spring member through which moves a lead advance-retract member which is keyed to longitudinal grooves in the inner barrel wall.
If the lead is subjected to excessive pressure during use, it is caused to partially retract into the tip by virtue of axial compression of the helical spring, thereby reducing the likelihood of lead breakage.
Description
MECHANICAL ENCIL
BACKGROUND OF THE INVENTION
For many years, the lower-prlced end of the pencil market has been dominated by eonventional wooden pencils w~th mechanical pencils being unable to secure but a minor portion of the market. A number of factors have contributed to this division of market share, most importantly, the relative expense o~ the mechanieal pencils which have been made available requiring that they be regarded as nondisposable items. Many attempts have been made to develop a simplified mechanical pencil which can compete wLth the less expensive wood pencils. Such pencil would overcome the dis~dvantages of the need to sharpen the point and the ~act that the entire length of the wooden pencil is no~ usable. Although some of the designs for disposable mechanical pencils in the prior art would appear to be less expensive to manufacture than conventional mechanical pencils, they are still generally much more expenslve than the common wooden pencil and hence have not been able to acquire a sign~ficant share of that market.
Among such designs is that shown in U.S. Patent 3,771,882, which employs a longitudinally movable finger pro~ecting from the side of the pencil barrel to ~dvance the lead as it is consumed durin8 use.
12~99 ~5;r3~ ¦
The design shown in U.S. P~tent 3,806,262 attempts to simpllfy a mechanical pencll design by elimina~ing the need for fin~er-actuated advancement of the lead, rely~ng lnstead on a translatlng member m~unted within a flexible tubular pencil barrel to translate deform~tion forces applied to the pencil barrel by the fingers to axlally advance the lead as needed.
The mechanical pencll described in U.S. Patent 4,136,980 attempts to slmplify mechanical pencil construction in a manner in which the back and forth movements o~ the pencil lead are controlled by a lead carrier having a spiral gulde travelllng along the splral grooves formed on the inslde of the pencll barrel and moving in response to manual rotation of the cap which holds one end of the supporting member.
Most of the mechanlcal pencils whlch have been commerciali~ed successfully have relied upon the use of 8 helical feed mechanism to advance or retract the lead in response to the relative rotation of the body of the pencil and either its tip or cap. Such pencils are exemplified in U.S. Patents 2,161,889; 2,356,509;
BACKGROUND OF THE INVENTION
For many years, the lower-prlced end of the pencil market has been dominated by eonventional wooden pencils w~th mechanical pencils being unable to secure but a minor portion of the market. A number of factors have contributed to this division of market share, most importantly, the relative expense o~ the mechanieal pencils which have been made available requiring that they be regarded as nondisposable items. Many attempts have been made to develop a simplified mechanical pencil which can compete wLth the less expensive wood pencils. Such pencil would overcome the dis~dvantages of the need to sharpen the point and the ~act that the entire length of the wooden pencil is no~ usable. Although some of the designs for disposable mechanical pencils in the prior art would appear to be less expensive to manufacture than conventional mechanical pencils, they are still generally much more expenslve than the common wooden pencil and hence have not been able to acquire a sign~ficant share of that market.
Among such designs is that shown in U.S. Patent 3,771,882, which employs a longitudinally movable finger pro~ecting from the side of the pencil barrel to ~dvance the lead as it is consumed durin8 use.
12~99 ~5;r3~ ¦
The design shown in U.S. P~tent 3,806,262 attempts to simpllfy a mechanical pencll design by elimina~ing the need for fin~er-actuated advancement of the lead, rely~ng lnstead on a translatlng member m~unted within a flexible tubular pencil barrel to translate deform~tion forces applied to the pencil barrel by the fingers to axlally advance the lead as needed.
The mechanical pencll described in U.S. Patent 4,136,980 attempts to slmplify mechanical pencil construction in a manner in which the back and forth movements o~ the pencil lead are controlled by a lead carrier having a spiral gulde travelllng along the splral grooves formed on the inslde of the pencll barrel and moving in response to manual rotation of the cap which holds one end of the supporting member.
Most of the mechanlcal pencils whlch have been commerciali~ed successfully have relied upon the use of 8 helical feed mechanism to advance or retract the lead in response to the relative rotation of the body of the pencil and either its tip or cap. Such pencils are exemplified in U.S. Patents 2,161,889; 2,356,509;
2,563,128; and 2,866,438.
While it has generally been Çelt by those skilled in the art that a helical advance-retract mechanlsm could not be produced economically enough for use ln a disposble mechanical pencil, there has now been discovered ~
construction which may be manufactured in large volume at A lo~ enough price to compete more effectively with the conventional wooden pencil.
SUMMARY OF THE INVENTION
The present invention relates to a low-cost mechanical lead pencil adapted for low-cost, mass production and overcoming the disadvantages of prior art devices. The pencil of the present invention provides an improved lead driving mechanism lnvolving cooperation between a low-cost, helical spring member through which moves a lead advance-retract member whlch ls keyed to longitudinal grooves in the inner barrel wall. The construction is such that excessive pressure on the pencil lead during use will cause the lead to be 05 partlally retracted into the tlp by virtue of axial compression of the helical spring, thereby reducing the likelihood of lead breakage.
In accordance with the present inven-tion, there is provided a mechanical pencil adapted for low-cos-t mass production and providing simplified assembly procedures comprising a hollow barrel member carrying a plurality of longitudinal. grooves on the inner wall thereof spaced apart from each other, a tip rotatably mounted on the barrel member, a helical spring member located axially within the barrel member and a lead advance-retract mechanism. The lead advance-retract mechanism comprises a body having forward and rearward ends. The forward end includes a lead holding bore to frictionally retain an end portion of a length of lead whereby the remaining portion of the length of lead can extend coaxially through the helical spring from the lead holding bore to the tip. The rearward end carries a plurality of solid lugs projecting outwardly from the body and spaced apart from each other about the body.
One of the lugs includes a lead portion defined by an extension extending toward the ~orward end. The extension is spaced apart from the body of -the advance-retract mechanism along the entire length of the extension so that the advance-retract mechanism i.s positioned within the helical spring and the helical spring passes between -the extension and the body of the advance-retract mechanismO The spacing between the longitudinal grooves and the lugs carried by the rearward end of the advance-retrac-t mechanism is arranged so that insertion of the lead portion into one of the grooves simultaneously aligns the other lug in another grooveO Relative movement between the barrel and tip members is converted to longitudinal movement o:E
- 3a -the lead advance-retract mechanism by ~irtue oE
cooperation between the lugs and grooves.
BRLEF DESCRIPTION OF T~E D~IN~S
Figure l ls an exploded view oE a complete 05 embodiment oE the operating mechanism oE a mechanical pencil in accordance with the presen-t invention.
Figure 2 is a sectional view inside elevation of the rearward portion oE a mechanical pencil of this invention illustrating the operation of -the lead advance-retract mechanism.
Figure 3 is a sectional view inside elevation of the Eorward portion of a mechanical pencil of this invention illus-trating the operation of the lead advance-retract mechanism.
Figure 4 is a sectional view in enlarged scale taken on line 4-4 of Figure 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figure l, the mechanical pencil of this invention comprises five essential parts, a hollow barrel 10, a rotatable tip 20, a lead advance-retract member 30, a helical metal spring 40, and an eraser or barrel plug 50.
ReEerring now to Figures 2-4, the hollow barrel 10 of the mechanical pen comprises a forward end 12 terminated by a bore portion of reduced inside diameter 14 and a rearward end 16 terminated by a bore portion of increased diameter 17 within which are located dimples 22 which serve to frictionally retain eraser 50. Mounted near the rearward end of barrel 10 is inteqrally molded clip member 18, which serves -to retain the mechanical pencil in a pocket or the like when it is not in use.
32~ r~ r~
~Z ~D~
Located axlally wlthin the bore oE barrel 10 are hellcal sprlng 40 t~plc~lly of metal, lead advance-retract ~ember 30, and lead 24. Located on the lnner wall of hollow barrel 10 are longltudin~l grooves 32, the pur os~ of which wlll be made clear hereinafter.
Re~errlng to Flgure 3, tip 20 comprlses conlcal forward portion 34 bearing Flnger-grlpping grooves 38 (best seen in Fl~ure 1) ~nd terminating ~t shoulder 36.
Rearward portion 44 of tip 20 comprises skirt 46 split by slots 48 and which bears lugs 50 to form a discontinuous shoulder which during assembly abuts shoulder 15 formed by bore portion o~ reduced inslde diameter 14.
Lead advance-retract mechanlsm 30 comprises forward end 54 within which is located lead holdlng bore 56 within which is frictionally retained lead 24. Mounted on rearward end 58 of lead advance-retract member 30 are lugs 60 and 61 which mate with barrel grooves 32 as sho~m best in Figure 4. Contiguous with a lug 61 is lug lead portion 62 wh~ch serves to reduce assembly problems by lnsuring that both of the lugs 60 are simultaneously allgned with grooves 32 during assembly.
Located axially within the bore of hollow barrel 10 is helical spring 40 whlch comprises forward portion 64 wh~ch is terminated by turns of reduced p1tch 66 which are keyed by frictional engage~ent with hollow bore o~ tip 20 and rearward portion 68 termlnated by open turn 70.
Xn operating the pencil to advance or retract the lead, barrel 10 and tip 20 are rotated with respect to each other. In so doing, spring 40 is caused to rotate ~ith tip 20 by virtue of the friction fit of spring turns of reduced pitch ~6. At the same time, lead advance~retract member 30 ls caused to rotate with barrel 10 by the keying action o~ lugs 61 and longitudinal grooves 32 on the inner wall of the barrel. As a resultt the rotational movement of tlp 20 and helical spring 40 is converted to longitudinal movement of lead advance-retract member 30 ~s the rotatlng turns of the spring bear upon lug 60 as shown ln Figure 2.
From the Çoregoing, it wlll be seen that there has been provided a prar,ical mechanlcal pencil of very simple constructlon, requiring a llm1ted number o~ parts and adapted for low-cost mass production.
While it has generally been Çelt by those skilled in the art that a helical advance-retract mechanlsm could not be produced economically enough for use ln a disposble mechanical pencil, there has now been discovered ~
construction which may be manufactured in large volume at A lo~ enough price to compete more effectively with the conventional wooden pencil.
SUMMARY OF THE INVENTION
The present invention relates to a low-cost mechanical lead pencil adapted for low-cost, mass production and overcoming the disadvantages of prior art devices. The pencil of the present invention provides an improved lead driving mechanism lnvolving cooperation between a low-cost, helical spring member through which moves a lead advance-retract member whlch ls keyed to longitudinal grooves in the inner barrel wall. The construction is such that excessive pressure on the pencil lead during use will cause the lead to be 05 partlally retracted into the tlp by virtue of axial compression of the helical spring, thereby reducing the likelihood of lead breakage.
In accordance with the present inven-tion, there is provided a mechanical pencil adapted for low-cos-t mass production and providing simplified assembly procedures comprising a hollow barrel member carrying a plurality of longitudinal. grooves on the inner wall thereof spaced apart from each other, a tip rotatably mounted on the barrel member, a helical spring member located axially within the barrel member and a lead advance-retract mechanism. The lead advance-retract mechanism comprises a body having forward and rearward ends. The forward end includes a lead holding bore to frictionally retain an end portion of a length of lead whereby the remaining portion of the length of lead can extend coaxially through the helical spring from the lead holding bore to the tip. The rearward end carries a plurality of solid lugs projecting outwardly from the body and spaced apart from each other about the body.
One of the lugs includes a lead portion defined by an extension extending toward the ~orward end. The extension is spaced apart from the body of -the advance-retract mechanism along the entire length of the extension so that the advance-retract mechanism i.s positioned within the helical spring and the helical spring passes between -the extension and the body of the advance-retract mechanismO The spacing between the longitudinal grooves and the lugs carried by the rearward end of the advance-retrac-t mechanism is arranged so that insertion of the lead portion into one of the grooves simultaneously aligns the other lug in another grooveO Relative movement between the barrel and tip members is converted to longitudinal movement o:E
- 3a -the lead advance-retract mechanism by ~irtue oE
cooperation between the lugs and grooves.
BRLEF DESCRIPTION OF T~E D~IN~S
Figure l ls an exploded view oE a complete 05 embodiment oE the operating mechanism oE a mechanical pencil in accordance with the presen-t invention.
Figure 2 is a sectional view inside elevation of the rearward portion oE a mechanical pencil of this invention illustrating the operation of -the lead advance-retract mechanism.
Figure 3 is a sectional view inside elevation of the Eorward portion of a mechanical pencil of this invention illus-trating the operation of the lead advance-retract mechanism.
Figure 4 is a sectional view in enlarged scale taken on line 4-4 of Figure 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figure l, the mechanical pencil of this invention comprises five essential parts, a hollow barrel 10, a rotatable tip 20, a lead advance-retract member 30, a helical metal spring 40, and an eraser or barrel plug 50.
ReEerring now to Figures 2-4, the hollow barrel 10 of the mechanical pen comprises a forward end 12 terminated by a bore portion of reduced inside diameter 14 and a rearward end 16 terminated by a bore portion of increased diameter 17 within which are located dimples 22 which serve to frictionally retain eraser 50. Mounted near the rearward end of barrel 10 is inteqrally molded clip member 18, which serves -to retain the mechanical pencil in a pocket or the like when it is not in use.
32~ r~ r~
~Z ~D~
Located axlally wlthin the bore oE barrel 10 are hellcal sprlng 40 t~plc~lly of metal, lead advance-retract ~ember 30, and lead 24. Located on the lnner wall of hollow barrel 10 are longltudin~l grooves 32, the pur os~ of which wlll be made clear hereinafter.
Re~errlng to Flgure 3, tip 20 comprlses conlcal forward portion 34 bearing Flnger-grlpping grooves 38 (best seen in Fl~ure 1) ~nd terminating ~t shoulder 36.
Rearward portion 44 of tip 20 comprises skirt 46 split by slots 48 and which bears lugs 50 to form a discontinuous shoulder which during assembly abuts shoulder 15 formed by bore portion o~ reduced inslde diameter 14.
Lead advance-retract mechanlsm 30 comprises forward end 54 within which is located lead holdlng bore 56 within which is frictionally retained lead 24. Mounted on rearward end 58 of lead advance-retract member 30 are lugs 60 and 61 which mate with barrel grooves 32 as sho~m best in Figure 4. Contiguous with a lug 61 is lug lead portion 62 wh~ch serves to reduce assembly problems by lnsuring that both of the lugs 60 are simultaneously allgned with grooves 32 during assembly.
Located axially within the bore of hollow barrel 10 is helical spring 40 whlch comprises forward portion 64 wh~ch is terminated by turns of reduced p1tch 66 which are keyed by frictional engage~ent with hollow bore o~ tip 20 and rearward portion 68 termlnated by open turn 70.
Xn operating the pencil to advance or retract the lead, barrel 10 and tip 20 are rotated with respect to each other. In so doing, spring 40 is caused to rotate ~ith tip 20 by virtue of the friction fit of spring turns of reduced pitch ~6. At the same time, lead advance~retract member 30 ls caused to rotate with barrel 10 by the keying action o~ lugs 61 and longitudinal grooves 32 on the inner wall of the barrel. As a resultt the rotational movement of tlp 20 and helical spring 40 is converted to longitudinal movement of lead advance-retract member 30 ~s the rotatlng turns of the spring bear upon lug 60 as shown ln Figure 2.
From the Çoregoing, it wlll be seen that there has been provided a prar,ical mechanlcal pencil of very simple constructlon, requiring a llm1ted number o~ parts and adapted for low-cost mass production.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A mechanical pencil adapted for low-cost, mass production and providing simplified assembly procedures comprising a hollow barrel member carrying a plurality of longitudinal grooves on the inner wall thereof spaced apart from each other, a tip rotatably mounted on the barrel member, a helical spring member located axially within the barrel member and a lead advance-retract mechanism comprising a body having forward and rearward ends, said forward end including a lead holding bore to fictionally retain an end portion of a length of lead whereby the remaining portion of the length of lead can extend coaxially through the helical spring from the lead holding bore to the tip, said rearward end carrying a plurality of solid lugs projecting outwardly from the body and spaced apart from each other about the body, one of said lugs including a lead portion defined by an extension extending toward said forward end and where the extension is spaced apart from the body of the advance-retract mechanism along the entire length of the extension so that said advance-retract mechanism is positioned within the helical spring and the helical spring passes between the extension and the body of the advance-retract mechanism and where the spacing between the longitudinal grooves and the lugs carried by the rearward end of the advance-retract mechanism is arranged so that insertion of the lead portion into one of the grooves simultaneously aligns the other lug in another groove and where relative movement between the barrel and tip members is converted to longitudinal movement of the lead advance-retract mechanism by virtue of cooperation between the lugs and grooves.
2. A mechanical pencil of claim 1 where the hollow barrel member carrys at least four longitudinal grooves.
3. A mechanical pencil of claim 1 where the grooves are spaced apart from each other to provide pairs of opposed grooves and where the opposed grooves are spaced apart from each other by a distance substantially equivalent to the distance which the lugs carried by rearward end of the advance-retract mechanism are spaced apart from each other so that insertion of the lead portion into one of the grooves of an opposed pair simultaneously aligns the other lug in the other groove of the opposed pair.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57873484A | 1984-02-09 | 1984-02-09 | |
| US578,734 | 1984-02-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1219555A true CA1219555A (en) | 1987-03-24 |
Family
ID=24314080
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000471881A Expired CA1219555A (en) | 1984-02-09 | 1985-01-10 | Mechanical pencil |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0151456B1 (en) |
| JP (1) | JPS60233000A (en) |
| CA (1) | CA1219555A (en) |
| DE (1) | DE3577825D1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2210587B (en) * | 1987-10-20 | 1992-04-01 | Mitsubishi Pencil Co | A mechanical pencil. |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA463498A (en) * | 1950-03-07 | E. Wehn Charles | Mechanical pencil | |
| DE478303C (en) * | 1929-06-22 | Huck Fa H | Pen | |
| US1627602A (en) * | 1921-04-29 | 1927-05-10 | Byron B Goldsmith | Mechanical pencil |
| DE454572C (en) * | 1925-03-10 | 1928-01-12 | Felss Geb | Pen |
| CH266391A (en) * | 1948-03-09 | 1950-01-31 | Gyger Fritz | Lead pencil. |
| JPS5040329U (en) * | 1973-08-06 | 1975-04-24 | ||
| US4136980A (en) * | 1977-04-12 | 1979-01-30 | Tae Yoon Leem | Mechanical pencil |
| JPS55144086U (en) * | 1979-04-03 | 1980-10-16 |
-
1985
- 1985-01-10 CA CA000471881A patent/CA1219555A/en not_active Expired
- 1985-01-29 EP EP19850100907 patent/EP0151456B1/en not_active Expired - Lifetime
- 1985-01-29 DE DE8585100907T patent/DE3577825D1/en not_active Expired - Lifetime
- 1985-02-05 JP JP2078085A patent/JPS60233000A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60233000A (en) | 1985-11-19 |
| EP0151456B1 (en) | 1990-05-23 |
| EP0151456A3 (en) | 1987-02-04 |
| JPH0557920B2 (en) | 1993-08-25 |
| EP0151456A2 (en) | 1985-08-14 |
| DE3577825D1 (en) | 1990-06-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |