US2174979A

US2174979A - Mechanical pencil

Info

Publication number: US2174979A
Application number: US32229A
Authority: US
Inventors: Paul S Hauton
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-09-09
Filing date: 1935-07-19
Publication date: 1939-10-03
Anticipated expiration: 1956-10-03

Description

Oct. 3, 1939. P. s. HAu'roN MECHANICAL PENCIL Original Filed Sept. 9, 1931 NVENTOR PAUL S. HAUTON AT1-ORNE Patented Oct. 3, 1939 UNITED STATES PATENT OFFICE Divided and t 1935, Serial No. 32,229

his application July 19,

1o Claims. (ol. 12o-"118) l This invention relates to mechanical pencils and their method of production.

- The object of the invention is to provide a generally improved and simplified structure which lends itself to economical production and especially to provide an improved threaded feed tube, lead holder and lead manipulating mechanism adapted to be rapidly. produced and assembled. 1u The present invention is related to my copending application, Serial Number 387,542 filed August 21, 1929, and patented October 1, 1935, as No. 2,015,673 and is a division of my application for Mechanical pencil filed September 9, 1931, l5 under Serial No. 561,829, and patented July 23,

1935, as No. 2,088,789.

In my application Serial Number 387,542 I have provided a threaded feed tube or helix consisting of an originally flat strip of metal, which is 20 coiled so that the strip edges are in contact, the

strip being cross-sectionally formed to provide a longitudinal offset in the strip of metal to form a thread, the edges of the strip ybeing primarily maintained in contact with each other by snugly fitting the coiled strip in the longitudinal bore of a casing, which is of substantially the same diameter as the tubular member formed from the coiled strip.

Attempts have been heretofore made to eliminate relative movement in the coils of a feed screw or helix, but such coils have either taken the form of a helically wound wire tacked to a casing which requires a casing bore of the same diameter as the feed tube or else a coiled strip of comparatively wide material having the successive coils spaced, Such Wide spacing hampering the selection of a desired pitch except by employing very thick material and even then permitting relative movement of the coils.

The present invention has achieved a rigid threaded feed tube which does not require a snug flt in the casing bore which can be formed from thin metal and in which the coils are definitely maintained in fixed relation to each other, and

this achieved by bonding the coils to each other either by flowing solder over the tube or by welding the successive coils to each other.

'I'he present invention also aims to provide an improved method of attaching a slotted rotatable lead holder to an operating member and a method of forming a winged tubular lead holder and ejecting mechanism for short lead lengths from a iiat strip of material adapted to receive a winged ejecting pin during its formation.

'Ihe characteristics and advantages of the invention are further referred to in connection with the following detailed description of the accompanying drawing, which shows certain embodiments of the invention' for the purpose of affording a clear understanding of the underlying 5 members thereof to those skilled in the art, but without limiting the invention to such detalls.

In said drawingf Fig.` l is a broken partly fragmentary longitudinal section of a pencil embodying one form 1o of the invention.

Fig. 2 is a longitudinal section of the lower end portion of the pencil showing another operative position of the lead actuating mechanism.

Fig. 3 is a section of a sleeve for guiding a 15 manually operable member at the end of the pencil remote from the Writing end and securing a threaded feed tube to a casing.

Fig, 4 is a perspective view showing a member for guiding a slotted member. 20

Fig. 5 is a fragmentary perspective view of one end of a slotted member.

Fig. 6 is a detailed view of one form of a threaded feed tube in the process of formation.

Fig. '7 shows another portion of a finished 25 threaded feed tube and showing one method of bonding the coils to form a rigid tube.

Fig. 8 is a perspective view of a lead holder.

lFig. 9 is a section of Fig. 8 on line 9 9.

Fig. 10 is a perspective view of an ejecting pin 30 adapted to be inserted in the lead holder shown in Fig. 8.

Fig. 11 is a partly fragmentary and partly sectional view of another embodiment of the writing end of the pencil. 35

Fig` 12 is a sideelevatio'n of the locking cup used in Fig. 11.

Continuing now by way of a more detailed description it is to be noted that instead of the comparatively thick casing of wood or other ma- 40 terial heretofore used, a thin shell or casing A preferably of some comparatively stiff light weight material, is tapered at the writing end cf the pencil, the material at the tapered end A' being slightly thickened to aiord a suitable t- 45 ting for a. lead guide tip and will be more fully described hereinafter in connection with the assembly of the pencil and the operation of the ejecting mechanism.

A threaded feed tube or helix B is concen- 50 trically located within and extends throughout the greater part of the length of the casing and because of its construction may be spaced from the'casing wall. One embodiment of this threaded feed tube consists of a'tightly coiled threaded 55 strip of material having a coating of solder to maintain the successive coils in proper position and incidentally forming a rigid tubular member. Initially, this threaded feed tube is preferably a fiat strip of comparatively thin material and of such width as to provide the desired pitch for the threads as will be readily understood as the description proceeds. It is to be noted that while a flat strip is more easily obtained and handled, 'nevertheless other shaped strips might be used. This hat strip of material is offset formed by bending up one edge of the material to form vthe flange B' as indicated in Fig. 6 and then tightly coiled in a helical form to form a threaded tubular member, the flange B' forming a thread wall. This tightly coiled member is then coated with solder B" to form the rigid feed tube and bond the coils to each other. While in the illustrated embodiment a coating of solder is used to secure the successive coils in rigid position. the coils might be also bonded by spot or seam welding the contact between the successive coils. It is not absolutely essential that the strip be tightly coiled as a loosely coiled strip in which the spaced coils are bridged by a suitable material bonding the coils, is also within the contemplated scope of the invention. The threaded feed tube B thus formed is held in place by a cup-shaped member C frictionally iitting within the upper end of the casing A and having an annular bead C resting on the top edge of the casing A to maintain the cup-shaped member in proper position. The lower end of this cup-shaped member has an annular depending ange C" snugly fitting the outside of the threaded feed tube and secured thereto in any suitable manner as, for instance, by solder. Instead of a depending annular ange or hub as C", an opening in the cup-shaped member might be soldered or otherwise secured to the threaded feed tube although the annular ilange or hub as shown is preferable as aording a rmer support. The t of the cup-shaped member on the inside of the casing A and ange C" effectively maintains the threaded feed tube in proper relation to the casing. The upper end of this cup-shaped member above the bead C' may be and preferably is extended upwardly to form a bearing for the inverted cup E shown in Fig. 4, to which the slotted lead holder guide F is secured. To simply and effectively lock the lead holder guide F to the cup E, the holder is formed with'upstanding prongs F' which are preferably stamped from the material of the holder and bent outwardly and upwardly to engage prong end receiving openings E formed in the top wall of the cup E, and are spaced apart a suflicient distance preferably near the cup periphery so that the laterally projecting portions F" of the prongs have a substantialbearing against the inside of the cup wall. After the upstanding ends F of the prongs are inserted in openings E they are pressed down to overlie the top of the cup as shown in Fig. 1. The slotted lead holder guide F consists of a rotatable tubular member slotted at one side similar to that shown in my copending application Serial Number 387,542 referred to above, and its lower end is guided in the upstandlng sleeve G formed in the guide tip G which nishes oi the pencil at its writing end. In the lead holder guide F a lead holder G shown in Fig. 8 originally consists of a fiat blank having oppositely disposed correspondingly formed vembossed lugs or ears H and oppositely disposed correspondingly formed indents J. When the marginal edges of embossed lugs H are brought into registry with each other by forming a tubular member of the blank as shown in Fig. 8 a wing is formed thereby which is adapted to pass through the slot of slotted feed tube F for feeding the lead holder J relatively to the feed tube by engagement with threads B on rotation of member E. The tubular lead holder J contains a relatively movable ejecting pin K with a wing K' projecting through the longitudinal opening formed by the cleared portions J, the wing K' engaging threads of the feed tube B behind the wing H and so that it normally is near the end T of slot J while the lead holder is feeding a usable piece of lead. When, however, the lead holder J' shown in Fig. 8 arrives at a position near the writing end the wing H passes clear of the threads of the threaded feed tube B and strikes the end of sleeve G of the pencil tip. Its further movement toward the pencil tip is arrested and it idles on the end G. Wing K' still being in engagement with the threads advances the follower K relatively to holder J and ejects the small portion of lead still remaining in the lead holder. The movement of the lead holder is accomplished by the rotation of the slotted guide F which in turn is accomplished by the rotation of the cup-shaped member E in any convenient manner, preferably the means for rotating the cup-shaped member E taking the form of a ferrule L which frictionally tsthe cup E and may conveniently be extended upwardly at L' to receive the eraser M.

A modified form of assemblage for the guide tip and casing is shown in Fig. 11 in which the guide tip R is secured to the tapered portion of the casing A by a. locking piece, the upper portion of which is firmly pressed into engagement with the tapered portion of the casing A and the lower portion firmly pressed into engagement with a correspondingly shaped portion in the tip R.

This last arrangement has several advantages over the construction shown in Fig. 1 which are readily apparent to those skilled in the art. When a tip of the type shown in Fig. 11 is used the clutch or wing member H may be arrested by either striking the top of the locking piece or else striking the face of the taper depending on well-understood proportioning of the parts.

The operation of the pencil, which forms the subject of the present invention, will be fully understood by reference to my copending application Serial Number 387,542.

It is claimed:

1. A mechanical pencil comprising lead feed mechanism consisting of a plurality of parts, a casing having a tapered end and an exposed tapered lead guide tip having a cylindrical lead guide opening at its writing end press tted directly to the tapered end of the casing and having a plurality of co-axal bores of diierent diameter, each adapted to receive different parts of the lead feed mechanism. l

2. A mechanical pencil comprising lead feed mechanism consisting of a plurality of parts, a casing having a tapered end, a tip for the pencil having a cylindrical lead guide opening at its writing end and having a tapered peripheral portion, the tapered peripheral portion merging with the tapered end of the casing, to form a smooth exterior taper for thewriting end of the pencil and means to lock the tip directly to the casing with a press fit having a plurality of co-axial bores of different diameter, each adapted to receive different parts of the lead feed mechanism.

3. A mechanical pencil comprising lead feed mechanism consisting of a plurality of parts, a casing having a tapered end, a tip for the pencil having a cylindrical lead guide opening at its writing end and having a tapered peripheral portion, the tapered peripheral portion merging with the tapered end of the casing to form a smooth exterior taper for the writing end of the pencil, the tip having an upstanding sleeve engaging a portion of the inner surface `of the tapered end of the sleeve and projecting above such engaged portion.

4. A mechanical pencil comprising lead feed mechanism consisting of a plurality oi parts, a casing having a body portion with a tapered end. the tapered end having the material of greater cross-section than the rest of the casing and having an axial bore and terminating in a lower circular edge, the tip for the pencil having a tapered peripheral portion having an upper circular edge, the edge of the tapered portion of the tip abutting against the lower circular edge of the tapered end of the casing, the tip having an extended part having a cylindrical peripheral surface tting the axial bore of the casing with a press nt to lock the tip to the casing having a plurality of co-axial bores of different diameter, each adapted to receive different parts of the lead feed mechanism.

5. A mechanical pencil comprising lead feed mechanism consisting of a plurality of parts, a casing having a tapered end with an axial bore and terminating in a lower circular edge, feed mechanism axially located in the casing and spaced therefrom, a tip for the pencil having a cylindrical lead guide opening at its writing end having a tapered peripheral portion and an upper circular edge, the edge of the tapered portion of the tip abutting against the lower circular edge of the tapered end of the casing, the tip having a tubular extension fitting the axial bore of the casing with a press fit to lock the tip to the casing, a portion of the said feed mechanism being journaled within the tubular extension of the tip having a plurality of co-axial bores of different diameter, each adapted to receive different parts of the lead feed mechanism.

6. A mechanical pencil comprising lead feed mechanism consisting of a plurality of parts, a casing having a tapered end with an axial bore terminating in lower circular edge and feed! mechanism comprising a slotted feed tube and a helix axially located in the casing and spaced therefrom, a tip for the pencil having a tapered peripheral portion, and an upper circular edge, the edge of the tapered portion of the tip abutting against the lower circular edge of the tapered end of the casing and the tip having a. tubular extension fitting the axial bore of the casing with a press fit to lock the tip to the casing, the lower end of the slotted feed tube being journaled Within the tubular extension of the guide tip having a plurality of co-axial bores of diierent diameter, each adapted to receive different parts of the lead feed mechanism.

7. A mechanical pencil comprising a lead feed mechanism including a lead grip sleeve, a casing, an exposed tapered lead guide tip having a cylindrical lead guide opening at its Writing end, and a bore of larger diameter co-axial with the lead guide opening to slidably receive and center the lead grip sleeve in lead ejecting position, said tip having a cylindrical collar extending into the casing, the end of the said cylindrical portion being spaced from the casing, and adapted to limit the movement of the lead grip sleeve within the said bore.

8. A mechanical pencil comprising a lead feed mechanism consisting of a plurality of parts, a. casing having a tapered end, the wall of the tapered end being of greater thickness than the rest of the casing and an exposed lead tip having a cylindrical lead guide opening and a portion press-fitted to the tapered end, and having a plurality of co-axlal bores of diierent diameter, each adapted to receive different parts of the lead feed mechanism.

9. A mechanical pencil comprising lead feed mechanism consisting of a plurality of parts, a casing having a body portion with a tapered end of greater thickness than the rest of the casing and having an axial bore and terminating in a lower circular edge, a tip for the pencil having a cylindrical lead guide opening, said tip having a tapered peripheral end and an upper circular edge, the circular edge of the tapered portion of the tip abutting against the lower circular edge of the tapered end of the casing, the tip having an extended part having a cylindrical surface fitting the axial bore of the casing with a pressfit to lock the tip of the casing and an extended part projecting beyond the axial bore of the tapered end, said tip having a plurality of coaxial bores of different diameter, each adapted to receive different parts of the lead feed mechanism to align the lead with the lead guide opening.

10. A mechanical pencil comprising a lead feed mechanism consisting of a plurality oi parts, a casing having a tapered end, and an exposed lead tip having a cylindrical lead guide opening and a portion press-fitted to the tapered end, and having a plurality of co-axial bores of different diameter, each adapted to receive different parts of the lead feed mechanism.

PAUL S. HAUTON.