GB1581410A

GB1581410A - Propelling pencil

Info

Publication number: GB1581410A
Application number: GB2582078A
Authority: GB
Original assignee: Gillette Co LLC
Current assignee: Gillette Co LLC
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1980-12-10

Description

(54) PROPELLING PENCIL (71) We, THE GILLETTE COM PANY, a Delaware Corporation, of Prudential Tower Building, Boston, Massachusetts 02199, States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: This invention is concerned with writing instruments and in particular to pencils of the so-called clutch type having a lead propelling mechanism including a lead reservoir connected at its forward end with a feed tube which is split longitudinally into a plurality of clutch jaws for gripping a length of lead extending through the feed tube, a collar capable of limited axial movement surrounding the jaws for cooperation with the jaws to press them inwardly to grip the lead, holding means for gripping the lead frictionally adjacent a forward end of the pencil barrel, and a spring for urging the reservoir rearwardly with respect to the barrel, the propelling mechanism being so arranged that predetermined lengths of lead can be extruded successively by repeatedly pressing the reservoir forwards against the force of the spring and releasing the reservoir to return under the action of the spring.

For convenience such pencils are referred to hereinafter as "of the clutch type" In operation, when the reservoir is moved forwards the jaws, held pressed against the lead by the collar, and the lead gripped by the jaws move forwards with the reservoir, as does the collar itself, at least initially.

After a certain axial displacement the collar is arrested. for example by abutment with a front stop. while the reservoir, jaws and lead continue to move forwards. The jaws eventually disengage from the collar and spring apart to release the lead. As the lead is carried forwards by the jaws it is pushed through the holding means. If the reservoir is now released to return to its initial position, the jaws and collar move back with it but the lead, held by the holding means does not and remains in the advanced position. The rearward displacement of the collar is arrested, for example by engagement with a rear stop, and as the jaws continue to move back through a final part of the return stroke they are urged inwardly by the collar to grip the lead again ready for the next actuation to project another length of lead.

Hitherto it has been the general practice to provide pencils of the clutch type with an actuator button which is connected to the rear end of the lead reservoir and protrudes through the rear end of the pencil barrel.

The actuator button must be depressed repeatedly to cause predetermined lengths of lead to be fed successively through the writing tip of the pencil.

According to the present invention there is provided a pencil of the clutch type comprising a casing divided transversely into two parts, and means for causing longitudinal movement of the reservoir within the casing to feed a length of lead therefrom in response to relative angular displacement of the two casing parts.

Although it is possible to arrange the casing parts to be continuously rotatable with respect to each other in order to drive the reservoir forwards repeatedly for projecting the lead, in a presently preferred embodiment of the invention the relative angular displacement between the casing parts required to produce a complete axial stroke of the reservoir is less than 90" and the casing parts are returned automatically to their initial positions when released after being turned to move the reservoir forwards. The necessary angular displacement between the casing parts is preferably within the range of about 30 to 60" which allows easy single handed operation of the pencil propelling mechanism.Furthermore, to facilitate the lead feeding operation even further the casing parts can, in the preferred embodiment, be turned in either direction to advance the reservoir and hence the lead.

Conveniently the two casing parts may be a barrel and a false cap.

In a preferred form of pencil embodying the invention, which is described in greater detail below, the means for displacing the reservoir in response to relative rotation of the casing parts comprises a cam mechanism including a cam member having an axially directed cam surface and fast with a false cap part of the pencil casing, and a cam follower having a projection which cooperates with the cam surface, the cam follower being held against rotation relative to a barrel part of the casing, but axially movable within the casing, and in engagement with the rear end of the reservoir. The cam follower is held against rotation by a guide sleeve having a longitudinal slot in which the projection on the cam follower engages.

The cam is conveniently keyed against rotation within the false cap by a pocket clip.

A better and more complete understanding of the invention will be had from the following detailed description, given by way of example with reference to the accompanying drawings, in which: Figure 1 is an axial section through the writing end part of a clutch type pencil in accordance with the invention; Figure 2 is an axial section through the rear end of the pencil of Figure 1; Figure 3 is an exploded perspective view of the cam and cam follower; and Figure 4 is a perspective view of the cam, cam follower and cam follower guide sleeve as assembled in the pencil.

The clutch type pencil illustrated in the drawings has a main outer casing formed by two parts, namely a barrel 1 and a false cap 2. Received within a forward end portion of the barrel 1 is a tubular inner casing member 3 the outer surface of which is shaped to be a close fit in the barrel. The inner casing member 3 has a stepped bore and adjacent its forward end defines an internal, rerwardly facing shoulder 4 against which abuts a shoulder formed on a tubular clutch sleeve 5 positioned coaxially within the member 3.

The clutch sleeve is externally screw threaded over a portion 6 proturbing from the member 3 and a writing tip part 7 of the pencil is screwed onto the sleeve portion 6.

A collar 8 is axially trapped within the front end of the clutch sleeve S by front and rear stops formed by a shoulder 9 on the sleeve and a ring element 10 fixed in the sleeve.

The collar 8 is slidable axially between the front and rear stops and has a conical inner surface which tapers rearwardly, for cooperation with three similarly tapering clutch jaws 11 provided by a tubular collett 12. The collett is split longitudinally by three slots 13 extending longitudinally from the front end of the collett so that the jaws are effectively mounted on resilient arms for radial movement. The rear end of the collet is fixedly attached to the front end of a lead guide tube 14, the rear end of which is fixed within a reduced diameter extension 15 of a lead reservoir 16. The end face of the guide tube and the internal shoulder 17 formed in the reservoir define a conical surface for feeding leads contained in the reservoir automatically under gravity towards the bore of the guide tube 14.In Figure 1 a single length of lead 18 is shown extending from the reservoir 16 through the guide tube 14 and the collett 12 and through a closely fitting bore in the end of the writing tip part 7. A sleeve 20 of rubber or other resilient material is accommodated within a counterbore in the tip part and serves to grip frictionally the lead 18 which passes through it, as will become apparent. A coil compression spring 19 is interposed between the rear end of the clutch casing 5 and the forward end of the reservoir 16 and serves to urge the reservoir and hence also the guide tube 14 and collett 12 rearwardly with respect to the clutch casing 5, inner casing member 3, the tip part 7 and barrel 1, which are all fixed relative to one another.As seen in Figure 1, the jaws 11 urged rearwardly by the spring 19 press the collar 8 against the rear stop 9 and are urged inwardly thanks to the cooperating taper surfaces of the jaws and collar to grip the lead 8. To advance a length of the lead 18, the reservoir is moved forward by means described below, against the force of spring 19. The collar 8 and jaws 11 also move forwards as does the lead which is held and pushed through the rubber sleeve 20 by the jaws 11. The axial movement of the collar 8 is arrested when the collar abuts the forward stop element 10, but the jaws continue moving forwards so that they disengage from the collar 8 and spring apart to release the lead 18 which then stops moving forward. If the reservoir 16 is now allowed to return to its initial position under the action of the spring 19, the jaws 11 move back also, out of engagement with the lead which is held by the rubber sleeve 20. When the jaws engage the collar 8 they push it back until it once more engages the stop 9, as seen in Figure 1, and as the jaws continue to move through a final part of their return stroke they are urged inwardly by the collar 8 to grip again the lead 18 ready for the next lead advancing operation. Thus, reciprocation of the lead reservoir causes a stepwise feed of the lead 18 through the writing tip of the pencil.

The mechanism for driving the reservoir forwards to advance a length of lead is housed within the cap 2 and is shown in Figures 2 to 4. The cap 2 has a hole at the rear end for receiving the shorter limb 25 of an L-shaped pocket clip 21. Accommodated in the rear end of the cap is a bush 22 having a hexagonal socket 23 in the front end and a transverse slot 24 in the rear end. The clip limb 25 is engaged in the slot 24 and has a tapped hole which aligns with the bore of the bush 22. A tubular cam 26 having a stepped diameter has a hexagonal rear end portion 27 which is inserted in the complementarily shaped socket 23 of the bush.

A cylindrical guide sleeve 28 has an internal flange held axially between the front face of the bush 22 and a rearwardly directed external shoulder on the cam. A screw 29 threaded over only a reduced diameter end portion is passed through the cam 26 and the bush 22 and screwed into the tapped hole in the clips shortcr limb 25. The shoulder 30 on the screw 29 engages the clip to prevent the screw being over-tightened to such a degree that operation of the cam mechanism is impeded.

The guide sleeve 28 is fast with a surrounding action tube 31 which is crimped to the sleeve. The action tube is firmly held in the pencil barrel by a sleeve 32 and is tightly gripped or made secure with adhesive to be fast with the barrel 1. The forward end of the action tube 31 (not shown) abuts against the rear end of the inner casing member 3 shown in Figure 1. The cap 2 is rotatable on a rear end portion of the sleeve 32 and is retained thereon by an internal projection 33 which locates in an annular groove 34 in the sleeve 32.

A cam follower 35 has a rear end portion inserted into the forward end of the cam bore and a cylindrical recess in its forward end receives an end closure member 36 fitted to the end of the lead reservoir 16.

The member 36 is biased into engagement with a radial should 37 in the cam follower 35 by the spring 19 (Figure 1). The cam follower has an integral longitudinal projection 38, the rear end of which contacts the axially directed cam surface 39 of the cam 26, and which is received in an axial slot 40 in the guide sleeve 28 so that the follower is held rotationally fast with the sleeve 28 and hence the action tube 31 and barrel 1. The projection 38 is urged into contact with the cam by a weak coil spring 41 inserted between an inner tube 42 fitted in the action tube 31 and an integral collar 43 or the cam follower.

From the foregoing description it will be understood that when the cap 2 is turned relative to the barrel 1. the clip 21 and therefore the bush 22 and the cam 26 turn, but the cam follower 35 and guide sleeve 28 remain fast with the action tube 31 and barrel 1.

The cam surface 39 on the cam can be seen in Figure 3 to have two steeply sloping portions 44 each interconnecting an axial outer end portion 45 and an inner end at which the portions 44 meet. As a result of this cam configuration the cam can be turned in either direction from the position shown in the drawings to cause the cam follower projection 38 to slide up along a sloping cam surface portion 44 driving the cam follower and the lead reservoir 16 forwards through a full stroke to advance a length of the lead 18. The axial portions 45 of the cam surface serve to limit the angle through which the cam 26 can be turned relative to the follower by striking against the sides of the projections 38, the permitted rotation as illustrated being approximately 60 in each direction.The steep slope of the cam surface portions 44 ensures that when the cam is turned by twisting the cap 2 to move the lead reservoir forward and is then released, the cam 26 and cap 2 are returned automatically to their initial positions (Figure 2) due to the force of the springs 19 and 41 acting on the follower 35.

The cam mechanism avoids the need for an actuating button protruding through the rear of the pencil casing allowing the clutch pencil to take on the general appearance more commonly associated with pens.

Furthermore, the mechanism allows easy single-handed operation of the lead propelling mechanism.

It will be appreciated by those skilled in the art that the described cam configuration is not the only one possible. It could for example be so shaped that the cap is rotatable continuously in one direction relative to the barrel to cause repeated operation of the lead advancing clutch mechanism. Other modifications are, of course, also possible without departing from the scope of the claims. One possibility is that the action tube 31 could be omitted by extending the sleeve 32 rearwardly and fixing it directly to the guide sleeve 28.

It is to be noted that the lead reservoir can be recharged with leads when they have all been used up by pulling the action tube 31 with the cap 2 and the cam mechanism in its entirety out of the barrel 1, to leave the rear end of the reservoir 16 exposed. The closure plug 36 is then just removed to allow a fresh supply of leads to be loaded into the reservoir, after which the pencil parts are reassembled.

WHAT WE CLAIM IS: 1. A pencil of the clutch type comprising a casing divided transversely into two parts, and means for causing longitudinal movement of the reservoir within the casing to feed a length of lead therefrom in response to relative angular displacement between

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. forwards to advance a length of lead is housed within the cap 2 and is shown in Figures 2 to 4. The cap 2 has a hole at the rear end for receiving the shorter limb 25 of an L-shaped pocket clip 21. Accommodated in the rear end of the cap is a bush 22 having a hexagonal socket 23 in the front end and a transverse slot 24 in the rear end. The clip limb 25 is engaged in the slot 24 and has a tapped hole which aligns with the bore of the bush 22. A tubular cam 26 having a stepped diameter has a hexagonal rear end portion 27 which is inserted in the complementarily shaped socket 23 of the bush. A cylindrical guide sleeve 28 has an internal flange held axially between the front face of the bush 22 and a rearwardly directed external shoulder on the cam. A screw 29 threaded over only a reduced diameter end portion is passed through the cam 26 and the bush 22 and screwed into the tapped hole in the clips shortcr limb 25. The shoulder 30 on the screw 29 engages the clip to prevent the screw being over-tightened to such a degree that operation of the cam mechanism is impeded. The guide sleeve 28 is fast with a surrounding action tube 31 which is crimped to the sleeve. The action tube is firmly held in the pencil barrel by a sleeve 32 and is tightly gripped or made secure with adhesive to be fast with the barrel 1. The forward end of the action tube 31 (not shown) abuts against the rear end of the inner casing member 3 shown in Figure 1. The cap 2 is rotatable on a rear end portion of the sleeve 32 and is retained thereon by an internal projection 33 which locates in an annular groove 34 in the sleeve 32. A cam follower 35 has a rear end portion inserted into the forward end of the cam bore and a cylindrical recess in its forward end receives an end closure member 36 fitted to the end of the lead reservoir 16. The member 36 is biased into engagement with a radial should 37 in the cam follower 35 by the spring 19 (Figure 1). The cam follower has an integral longitudinal projection 38, the rear end of which contacts the axially directed cam surface 39 of the cam 26, and which is received in an axial slot 40 in the guide sleeve 28 so that the follower is held rotationally fast with the sleeve 28 and hence the action tube 31 and barrel 1. The projection 38 is urged into contact with the cam by a weak coil spring 41 inserted between an inner tube 42 fitted in the action tube 31 and an integral collar 43 or the cam follower. From the foregoing description it will be understood that when the cap 2 is turned relative to the barrel 1. the clip 21 and therefore the bush 22 and the cam 26 turn, but the cam follower 35 and guide sleeve 28 remain fast with the action tube 31 and barrel 1. The cam surface 39 on the cam can be seen in Figure 3 to have two steeply sloping portions 44 each interconnecting an axial outer end portion 45 and an inner end at which the portions 44 meet. As a result of this cam configuration the cam can be turned in either direction from the position shown in the drawings to cause the cam follower projection 38 to slide up along a sloping cam surface portion 44 driving the cam follower and the lead reservoir 16 forwards through a full stroke to advance a length of the lead 18. The axial portions 45 of the cam surface serve to limit the angle through which the cam 26 can be turned relative to the follower by striking against the sides of the projections 38, the permitted rotation as illustrated being approximately 60 in each direction.The steep slope of the cam surface portions 44 ensures that when the cam is turned by twisting the cap 2 to move the lead reservoir forward and is then released, the cam 26 and cap 2 are returned automatically to their initial positions (Figure 2) due to the force of the springs 19 and 41 acting on the follower 35. The cam mechanism avoids the need for an actuating button protruding through the rear of the pencil casing allowing the clutch pencil to take on the general appearance more commonly associated with pens. Furthermore, the mechanism allows easy single-handed operation of the lead propelling mechanism. It will be appreciated by those skilled in the art that the described cam configuration is not the only one possible. It could for example be so shaped that the cap is rotatable continuously in one direction relative to the barrel to cause repeated operation of the lead advancing clutch mechanism. Other modifications are, of course, also possible without departing from the scope of the claims. One possibility is that the action tube 31 could be omitted by extending the sleeve 32 rearwardly and fixing it directly to the guide sleeve 28. It is to be noted that the lead reservoir can be recharged with leads when they have all been used up by pulling the action tube 31 with the cap 2 and the cam mechanism in its entirety out of the barrel 1, to leave the rear end of the reservoir 16 exposed. The closure plug 36 is then just removed to allow a fresh supply of leads to be loaded into the reservoir, after which the pencil parts are reassembled. WHAT WE CLAIM IS:

1. A pencil of the clutch type comprising a casing divided transversely into two parts, and means for causing longitudinal movement of the reservoir within the casing to feed a length of lead therefrom in response to relative angular displacement between

the two casing parts.

2. A pencil as claimed in Claim 1, wherein the casing parts are angularly displaceable through a predetermined limited angle to produce a complete forward stroke of the lead reservoir.

3. A pencil as claimed in claim 2 wherein said limited angle is not greater than 90".

4. A pencil as claimed in claim 2, wherein said limited angle is within the range of about 30 to 600.

5. A pencil as claimed in claim 1,2, or 3, wherein the two casing parts are relatively angularly displaceable in either direction to cause forward movement of the reservoir.

6. A pencil according to any one of the preceding claims, wherein said means is arranged to return said casing parts to a predetermined relative angular position following relative angular displacement of the casing parts from said position to feed a length of lead from the reservoir and subsequent release of the casing parts.

7. A pencil as claimed in any one of the preceding claims wherein said means comprises a cam member having an axially directed cam surface, and a cam follower member, the cam member and cam follower member being fast with the respective casing parts.

8. A pencil as claimed in any one of the preceding claims wherein the two casing parts are a barrel and an imitation cap.

9. A pencil as claimed in claims 7 and 8, wherein the cam member is fast with the cap and is keyed against rotation relative thereto by a pocket clip which extends through a hole in the cap.

10. A pencil as claimed in claim 9, wherein a bush having a transverse recess is located in the ca, the clip engages in the bush recess, the cam member has a portion of non-circular cross-section received in a complementary socket in the bush, and the cam member, bush and clip are held axially together by a screw passing axially through aligned bores in the cam member and bus and threaded into a tapped hole in the clip.

11. A pencil as claimed in claim 9 or 10, wherein a longitudinally slotted guide sleeve surrounds the cam member and holds the cam follower against rotation with the cam member, the guide sleeve being rotatally fast with a tubular element fast with the barrel.

12. A pencil as claimed in claim 11, wherein the cam follower comprises a radial projection which contacts the cam surface and is engaged in a longitudinal slot in the guide sleeve.

13. A pencil of the clutch type substantially as herein described with reference to the accompanying drawings.