US3450482A

US3450482A - Pencil lead holder with fixed length feed

Info

Publication number: US3450482A
Application number: US645394A
Authority: US
Inventors: Virgil D Dorstewitz
Original assignee: TRU POINT PRODUCTS Inc
Current assignee: TRU POINT PRODUCTS Inc
Priority date: 1967-06-12
Filing date: 1967-06-12
Publication date: 1969-06-17
Anticipated expiration: 1986-06-17
Also published as: FR2049551A5; CH502903A; DE1929615A1

Description

June 17, 1969 v. D. DoRsTEwn'z PENCIL LEAD HOLDER WITH FIXED LENGTH FEED Filed June 12, 1967 V/Qa/ ors/ew//z BY y' ATTORNEY l N VEN TOR.

llllllilll""" `|"b United States Patent O 3,450,482 PENCIL LEAD HOLDER WITH FIXED LENGTH FEED Virgil D. Dorstewitz, Coloma, Mich., assignor to Tru Point Products Inc., Coloma, Mich. Filed .lune 12, 1967, Ser. No. 645,394 Int. Cl. B43k 2]/16, 2]/22 U.S. Cl. 401-67 9 Claims ABSTRACT F THE DISCLOSURE The construction involves a relatively few, inexpensively -formed and assembled, parts to provide advancing or feeding motion of the lead in fixed increments, thus reducing the cost of the holder.

It is an object or feature of the invention that a pencil lead is automatically advanced a predetermined distance from an outer barrel and chuck socket by providing a spring returned chuck jaw holder with jaws to grip the lead in operating position, coacting stop on a push button and the jaw holder that permit a predetermined lost motion between the button and the holder before the jaws open to release the lead, and coacting stops on the lead holder and button that first limit advance of the lead holder and then limit its return to the same predetemined distance, relative to the jaw holder when the button is released.

yIt is a further feature of the invention that the coacting stops described above are formed in part by economical means of beads and flanges formed in the tubular elements that form the button, the jaw holder and the lead holder.

It is a further -feature of the invention that the jaw holder is returned to retracted position by a relatively still spring, while the button and lead holder are returned to retracted position by a relatively weak spring bearing against a stop on the jaw holder.

The drawings of which there is one sheet illustrate two alternative forms of the lead holder.

FIGURE l is a longitudinal cross sectional view partially broken away through a first form of the lead holder.

FIGURE 2 is a front elevational view of the holder.

FIGURE 3 is a fragmentary longitudinal cross sectional view through the rear end of the holder showing the lead feeding mechanism in partially actuated position.

FIGURE 4 is a Ifragmentary longitudinal cross sectional view partially broken away showing the feeding mechanism in FIGURES 1 and 3 in fully actuated lead feeding position.

FIGURE 5 is a fragmentary longitudinal cross sectional view similar to FIGURE 3 illustrating a modified form of the lead feeding mechanism.

The first form of the lead holder and feeding mechanism shown in FIGURES l through 4 comprises a tubular body or barrel 1 of hexagonal cross section having a forwardly tapering conical end 2 at the front which merges into a chuck seat member 3. The rear end of the barrel is open at 4. The forward portion of the seat 3 has a concave or forwardly diverging conical socket surface 5 to the rear of which the chuck seat merges into a forwardly converging conical body 6 with a radially inturned flange 7 at its rear end. The conical seat 5 coacts in a well known manner with a collet chuck generally indicated at 8 and having angularly spaced jaws 9 with rearwardly tapering surfaces 10. When the jaws 9 are compressed by retraction in the seat surfaces 5, the jaws function to tightly grip the surface of a pencil lead 11.

The chuck jaws 9 are connected or merge into a tubular cylindrical rear portion 12 which is connected as by the threads 13 to the forward end of a push tube 14. Intermediate o'f its ends the push tube 14 is axially upset to form a projecting bead or abutment 15. A relatively stiff coil lspring 16 bears between the flange 7 on the chuck socket body and the projection or abutment 15 to bias the push tube and the chuck 8 into lead gripping position in the socket 3. Toward its rear end the push tube is provided with a second axially upset rib or abutment 17 located near the rear end of the barrel.

Positioned telescopingly around the rear end of the push tube and projecting through the open rear end 4 of the barrel is a cylindrical push button 18 having an inwardly turned flange or abutment 19 which coacts with the forward face of the abutment 17. The rear end of the push button has an inwardly turned flange 20 defining an opening 21. Positioned within the rear of the push button is a short cylindrical spacer or retainer 22 having an inwardly turned annular flange or abutment 23 spaced rearwardly from the flange 19. A second coil spring 24 which is more resilient 'than the spring 16 is compressed between the rear face of the abutment 17 and the forward face of the flange 23.

Positioned telescopingly within the push tube 14 and the chuck seat body 12 is a cylindrical lead holding tube 25 having an outwardly turned annular flange 26 on its rear end. Intermediate of its ends the lead holding tube is reduced in diameter as at 27 and provided with elongated semicylindrical gripping fingers 28 spaced by slots 29. The lingers 28 constitute gripping means for engaging the surface of the lead 11 -with suflicient pressure and frictional force to prevent the lead from falling forwardly through the jaws 9 when the jaws are released.

In order to feed the lead forwardly from the holder and the jaws 9, the push button 18 is pressed part way forwardly `as shown in FIGURE 3 until the flange or abutment 23 engages the rear end of the push tube. This initial forward movement of the push button is accommodated by compression of the relatively light spring 24 without releasing the chuck jaws 9 which are held retracted by the relatively stiff spring 16. The lead holding tube 25 remains stationary during this fast depressing motion of the push button so that the rear end of the lead holding tube and an outwardly projecting annular flange 26 thereon moves relatively toward the rear of the push button in the space between the abutment flange 23 and the rear flange 20 on the push button.

Continued inward pressure on the push button causes the flange 23 to advance the push tube 14 until the jaws 9 are moved forwardly out of the chuck seat 5 to release the jaws from their gripping engagement with the lead 11. This -nal advancing motion of the push tube is accommodated by compression of the relatively stiff spring 16. As soon as the chuck jaws 9 release the lead, the lead and the lead holding tube 14 are free to advance within the lead holding tube and the chuck socket body 12. lf the barrel 1 is held upright this advance of the lead and the lead holding tube is accomplished by gravity but in any case the advancing motion of the lead is limited by the inwardly turned flange 23 on the retaining cylinder which engages and stops the flange 26 on the rear end of the lead holding tube as is shown in FIGURE 4. The distance of the advancing motion of the lead is predetermined by axial length of the space between the flange 23 of the retainer cylinder 22 and the rear flange or abutment 26 on the lead holding tube.

After the lead holding tube and the lead carried thereby have been advanced, the push button 18 is released and during the initial released movement of the push button the stronger spring 1'6 returns the push tube 14 to its chuck engaging position as shown in FIGURE l in which the jaws 9 grip the surface of the lead at a new point in advanced position of the lead and rearwardly along the length of the lead. After the jaws have gripped the lead, the chuck and the push tube are arrested in their original retracted position, after which the relatively weaker spring 24 retracts the push button from within the barrel until this retracted motion is stopped by engagement of the flange or abutment 19 with the annular` abutment 17. The spring 24 is strong enough to overcome the frictional grip of the friction gripping elements 28 on the front end of the lead holding tube so that the lead holding tube retracts within the push tube by sliding rearwardly along the lead held stationary in its new advanced .position by the jaws 9. The parts have thus reassumed their initial lead Aholding positions shown in FIGURE 1.

In the modified form of the lead holding and feeding device the body or barrel IA is the same as that shown in FIGURES 1 through 4 as is the push tube 14A. The push button 18A may be somewhat longer than the corresponding push button 18 in FIGURE 3 and the spacing cylinder or retainer 22A may be correspondingly longer so that more axial space is provided between the inturned flange 23A and the rear end of the push button.

The lead holding tube 25A is provided with an axial upset forming the radially projecting rib or abutment 30 which performs the same function as the flange 26 in limiting forward feeding motion of the lead holder and the lead. The abutment 30 acts as a third spring 31 positioned within the push button with its other end bearing against the inturned flange 20A.

The modified holding and feeding structure of FIGURE operates in the same manner as the first form of the lead holder except that the barrel need not be held vertically to advance the lead holding tube and the lead. The spring 31 will advance the lead holding tube behind the inturned liange 23A as soon as the jaws of the holder are released, The modified structure thus feeds the lead while in any horizontal or inverted position and the second spring 24A needs only to retract the retaining sleeve 22 and the lead holding tube against the frictional grip of the feed and of the lead gripping tube plus the pressure of the spring 31.

What is claimed as new is:

.1. A pencil lead holding and feeding apparatus comprisrng:

a lead holding tube having means near its front end adapted to frictionally grip a pencil lead,

a hollow tubular barrel positioned in spaced relation around said holding tube and open at each end, a socket for a collet chuck secured in the front end of said barrel,

a collet chuck having jaws in coacting relation to said socket and opening forwardly relative to said socket,

a push tube positioned telescopically within said barrel and around said holding tube and having its forward end connected to the rear end of said chuck within said barrel,

a first abutment on said push tube and located between the ends of said barrel,

a first spring in said barrel compressed axially between said barrel and a forwardly facing part of said first abutment,

a tubular push button positioned in axially slidable telescopic relation to the rear of said barrel and the rear end of said push tube,

first coacting stop means on said push button and said push tube engageable in axially rearward limiting relation of said push button relative to said push tube,

second coacting stop means on said push button and said push tube engageable in axially forwardly advancing relation of said push tube by said push button,

said first and second coacting stop means being spaced axially and permitting forward movement of said push button relative to said push tube,

a second spring weaker than said first spring positioned in forwardly compressible engagement between a forwardly facing abutment on said push button and a rearwardly facing abutment on said push tube to bias said push button rearwardly into engagement of said first coacting stop means,

and third coacting stop means on said lead holding tube and said push button engageable in rearwardly feeding engagement of said holding tube by push button,

said second spring being strong enough to overcome the frictional engagement of said lead holding tube with a pencil lead therein.

2. A pencil lead holding device as defined in claim 1 in which said push button is slidable within said barrel and around said push tube.

3. A pencil lead holding device as defined in claim 2 .in which said Afirst abutment is an annular rib upset outwardly from4 the wall of said push tube,

and in which said first spring bears against the rear end of said chuck socket.

4. A pencil lead holding device as defined in claim 3 in which said first coacting stop means includes a second rib upset from said push tube near the rear thereof,

and an inwardly projecting portion on said push button slidable along said push tube forwardly of said second rib. 5. A pencil lead holding device as defined in claim 3 in which said second coacting stop means includes a radially inwardly projecting portion on said push button engageable with the rear end of said push tube.

6. A pencil lead holding device as defined in claim 3 in which said third coacting stopvrneans includes an outturned fiange on the rear of said lead holding tube,

and an inwardly projecting part on said push button.

7. A pencil lead holding device as defined in claim 4 in which said second coacting stop means includes an annular retainer in the outer end of the pushgbutton and having an inturned flange at its front end radially overlapping the rear end of `said push tube,

said second spring being a coil with its ends engaged between said second rib and said inturned flange.

8. A pencil lead holding device as defined in claim 3 in which said second coacting stop means includes an annular retainer in the outer end of said push button with an inturned flange at its front end radially overlying the rear end of said push tube,

and in which said second spring has its ends engaged between said push button and the rear of said holding tube.

9. A pencil lead holding device as defined in claim 1 in which there is a third spring having its ends engaged between said holding tube and said push button to be compressed upon forward motion of the push button.

References Cited UNITED STATES PATENTS 2,5 09,849 5/195'0 Von Allmen 401--67 FOREIGN PATENTS 868,710 2/1953 Germany. 1,099,901 2/1961 Germany. 1,146,405 3 1963 Germany.

112,465 `11/ 1964 Czechoslovakia.

LAWRENCE CHARLES, Primary Examiner.

U.S. Cl. XR. 401-93