IL30192A - Writing instruments - Google Patents

Description

301 2/2 Writing instruments mm SBLA Cj 36701 - 2 - 30192/2 This invention relates to ifriting instruments of the type commonly referred to as drafting pencils in which lead is hold in a selectively operable chuck.

In drafting, and ©specially while designing, a draftsman or designer usually has two kinds of pencils available? on© having a relatively hard lead for drawing fine construction lines9 and one having a softer lead for drawing heavy lines and for lettering. This calls for keeping within reach two or more pencils having leads of different hardness and which can be selected for use as the drawing progresses. It is well known to those who have experience in this field that, more often than not, the particular pencil required is misplaced when needed thus causing either a great loss of time in searching for the required pencil, or the use of a pencil with an inappropriate lead hardness.

An ideal solution to this problem ¾jould be to have a pencil with a lead of different hardness at each end of the pencil. To change from one lead t© a lead of different hardness, one would merely invert the pencil in his hand. It is therefore an object of the present invention to provide a new and improved writing instrument of the type described above.

According to the present invention, there is provided a writing instrument comprising a cylindrical body slidably receiving, at each axial end, a tube terminating in a lead-grip that abuts the body and limits inward - 3 - 30192/2 movement of the tube, each grip being adapted to frictionally engage a piece of lead in the tube when tho grip abuts the body, means resiliently urging the grips into abutment with the body, and means to impart relative movement between a grip and the body for selectively disengaging lead in the grip.

Embodiments of the invention are illustrated by way of example in the accompanying drawings, whereins- Fig. 1 is a partial section of one embodiment of the invention; Fig. 2 illustrates a second embodiment of the invention? Fig. 3 illustrates a still further embodiment of the inventio J Fig. 4 illustrates the manner of operating the pencil illustrated in Figs. 1 and 35 and Fig. 5 illustrates the manner of operating the pencil shown in Fig. 2.

Referring now to Fig. 1, the \riting instrument comprises a length of slender tubing 1 contained within a cylindrical body which itself comprises a pair of end sections 3 and 3a interconnected by a center section 5p and a compression spring 4. The spring urges sections 3 and 3j away from each other and into engagement with lead-grips 2 and 2j on the respective ends of the tubing 1. Such engagement causes separate pieces of lead within each grip to be frictionally engaged by the respective - 4 - 30192/2 grips and suitably held In a position at which a sharpened end of the lead Is exposed for use.

To release either lead, 'the pencil is held as shown in Fig. 4 permitting the sections to slide relative to each other thus loosening the pressure on the lead-grips which will accordingly release the lead allowing it to slide in or out depending on the position of the pencil. To release one lead while the other remains unaffected, the upper grip may be held between the thumb and forefinger as shown in Fig. 4.

The embodiment of the invention shown in Fig. 3 is similar to that shown in Fig. 2 except that in this embodiment, two lead tubes 6 and 6a are provided and two separate springs 7 and 7jj, are provided. In addition, the cylindrical body is unitary, and an actuating cylinder 9 is slldably mounted within the body for selective movement by means of buttons 10 which pass through the walls of the body. Spring 7, pressing against a retainer ring 8 on the lead tubing 6, urges the lead-grip 2 into engagement with the free end of the body. Similarly, spring 7a acting on ring 8a urges tubing 6a inwardly so that the lead-grip 2a is brought into abutment with the body. The operation of the embodiment shown in Fig. 2 as illustrated in Fig. 5 wherein an operator may utilize his thumb nail for the purpose of pushing button 10 in one direction or the other thus permitting the lead-grips to selectively release the lead held in the respective tubes. - 5 - 30192/2 The embodiment shown in Fig. 3 is essentially the same as the embodiment shown in Fig. 1 except that two end sections that fit one within the other are provided and no separate middle section is needed. This permits the device shown in Fig. 3 to be mass produced and to be less expensive.

As a consequence of the construction in the present invention the fabrication and assembly of the writing instrument becomes quite simple with the result that an inexpensive but very effective device is achieved. 30192/2

Claims (7)

1. A writing instrument comprising a cylindrical body slidably receiving, at each axial end, a tube terminating in a lead-grip that abuts the body and limits inward movement of the tube, each grip being adapted to frictionally engage a piece of lead in the tube when the grip abuts the body, means resiliently urging the grips into abutment with the body, and means to impart relative movement between a grip and the body for selectively disengaging lead in the grip,

2. A writing instrument according to Claim 1, wherein a single tube interconnects each lead-grip and the body has two separate portions urged apart by a spring which constitutes . the means resiliently urging the grips into abutment with the body.

3. A writing instrument according to Claim 2, wherein the two separate portions of the body are slidably mounted in a sleeve that contains the spring which surrounds the tube.

4. A writing instrument according to Claim 3f wherein adjacent ends of the two separate portions are enlarged and support each end of the spring.

5. A writing instrument according to Claim 2, wherein the two separate portions of the body are telescopically received or*-within-the-other·

6. A writing instrument according to Claim 1, wherein each lead-grip is connected to a separate tube and is biased by a separate spring, and a plug interposed between the free ends of the tubes can be manually movable in either axial direction for selectively

7. Writing instruments substantially as described above^ by way of example and with reference to the accompanying drawings . 1 For the Applicants DR R S