US2303009A - Lead holder - Google Patents

Description

Patented Nov. 24, 1942 Unirse stares ParaNr Iors-Ir'l?.' {LEAlii HOLDER n v Fritz von'Allmen, Geneva.t Switzerland, assigner to Fabrique Suisse'de Crayons Caran dAche S. A., Geneva, Switzerland; a corporation'of Switzerland Application .my 2", 194.1, serial No. 400,839 ln lSwitzerland February 3, 1941 sola'ims. .(01. 12o-101)` Various types of lead holders are` already known with a devicefor feeding the lead, as, a result of pressure applied to acap. In order to obtain elective clamping of thelead so as to avoid` the lead being pushed back'into the interior of the body ofthe lead holder asa result-of the pressure exerted on the lead whileit'isbeing" used, it. has i these clamping jaws IbeingY subjected to theaction of' a spring which tends to hold their conical surface in Contact with the conical surface of the opening. This-type of lead holder is provided with a device for feeding the-lead formedby a member located in the interior Vof the lead holder. This member clamps the lead, at the endof the movement of the clamping jaws actuatedl by the cap; sol asto retain itA in` this.l position during the return movement of the -clampingjaws into their rest position. A 0

Other lead holders. have retaining device formed by jaws provided Ain the interior et the body of the lead holder andserving to'clamp the lead during the return movementof the clamping jaws. Y YJAll these devices have variousf defects inherent to their construction. In particular'theclamping jaws being very short, the ilexibil-ity of their limbsis insufficient and very'soon they no( longer clamp the lead after' theyv have beenrrelease'd from the seating cone and therefore no longer effect the feed. Consequently thegfeedof the lead, particularly when it is not calibrated accurately; is irregular ands-is no rlonger-effected correctly.

Further as the retaining device is provided in the interior of thebodyit is-invisibles'o` that it is'not possible for the user'fto see' directly whether the stoppage of the. feed; of the lead: is due to holder by which the above disadvantages are eliminated and* which is provid-ed with clamping jaws which emerge from the-body ofthe lead holderand of which the movements are controlled by the cap. Itis distinguished from known lead holders. by the factthat these clamping jaws Vare formed by feed members and retaining mem.-

- line VI-VI of Fig. 1.- and groupfbeing provided, with lretaining members' the exhaustion of the reserve of leads or rto' a tact with the preceding "lead engaged bythe clamping jaws.

The subject of the present invention is" aV lead 55 jaws' 5; The inner ends 'of' thelimbs301ithese and the other withfeed members 6. ,Y The bodyjl isl formed by a polygonal tube of whichone end is tapered and i's provided with' a conical4 opening l forming a seat for theV jaws which are rearwardly tapered. The guide tube d is rigidly secured to the magazine tube -2, preferably by clinching, andisprovided with two pins 8 of which'` the outer faces a lslide. along4 the inner walls b of the body l. The magazine tube. 2. is guided, centered and" prevented from rotation in the.` interior of tvhebody I by-vmeans of aV polygonal projection 9; Tojthe free end of the guide tube 4- there aresecured rigidly feed. members formed by a group' of'jaws-iiwhich emerge vfrom the'bodyl throughsaid conical opening l. The limbs of these jaws'arel resilient and are' formed in such a manner asln'ormallyto clamp the lead H'. They are also providedfwith a'conical'portion I2 maintained in' the clamping,` position inl errgagement with the conical'` opening 'l'by a' spring I3` which bea'rs'against.the'tapered portion'of the tube I andl actsupon the pinsfsecuredito'the guide tube Il.4 I

Between the limbs of thev feed jaws n e located retaining members formez by'rafgroupof jaws 5 are connected together in the interior of the body I because they are carried by a tubular body I4 whose inner end frictionally engages and is centred on a boss I provided on the guide tube 4. For the purpose of retaining the jaws and 6 angularly relatively to the guide tube 4, and to ensure a slidable resilient engagement of the end of the tubular body I4 im'th the boss I0, the aforesaid inner end is provided with longitudinal slots I5 with which the pins 8 engage.`

The limbs of the jaws 5 are resilient andare ping faces and 2l of the two sets of jaws subj ected to the action of the spring I3 and the shaped in such a manner that in the released 4'.'

position of the lead the latter can slide'between the gripping faces 2l) thereof'. The limbs of these jaws are provided with a conical:` portion I1 which is held in the clamping position in the conical opening 1 by the spring I3 which presses 5 against the flange I6 of the tubular body I4.

The feed movement of the lead is produced by exerting a push on the cap and may be divided into four phases:

a. Release of the lead Assuming that the internal mechanism of the pencil lead holder is in the position shown in Figs. l and 2, in which the spring I3 acting on the two sets of jaws tends to cause them to move inwardly into the body I and thus causes these to clamp the lead, so as to retain it axially and angularly, then when pressure is applied to the cap 3 the latter pushes the magazine tube'2, the guide tube 4 and the jaws 6, which are secured together, against the action of the spring I3. The jaws 5 partake of this movement as a result of their frictional engagement with the boss IIJ through the medium of the tubular body I4. The lead II is fed by the feed jaws 6. The movement of the retaining jaws 5 is limited by a shoulder I8 on the tube I4 which comes into engagement with the tapered part of the body I (Fig. 3).

b. Feed of the lead While continuing pushing the cap 3, the movemen't of theV latter effects forward movement of the feed jaws 6 which because of their gripping faces 2|, bearing against the lead, feed the latter. During Ythis phase the tube I4 slides on the boss IIl and the retaining jaws 5 rest with their shoulders I8 bearing against the tapered portion of the body I and its gripping faces 20 in the open position (Fig. 4). The movement of the cap is limited by the inner edge of the maga- Yzine tube 2 coming into Contact with the flange I6 of the tube I4.

c. Retention I When the cap 3 is released, the spring I3, acting on the pins 8, tends to cause the feed jaws 6, secured to the guide tube '4, to move rearwardly. The lead partakes of this movement'by reason of the action of the limbs of these jaws' which press their gripping faces 2I against the lead. The retaining jaws 5 also partake of this movement, as a result of the frictional engagement of the slotted end of the tube I4 with the boss Ill, until their conical surfaces I1 come into contact with the conical seating 1 ofthe opening, which effects the clamping of the gripping faces 20 against the lead II so as to retain the latter against the action of the gripping faces 2I of the feed jaws 6 (Fig. 5).

d. Tightem'ng of the jaws l The spring I3, acting on the pins 8, effects` the return ofthe feed jaws 6 into the position shown conical surfaces I2, I1 and 1.

From the foregoing it will be seen that dur-V ing the wholeV of the feed movement of the lead 'I Il this is always clamped by one or other of the rnally until the last reserve lead has been used completely. Further the feed of the lead can be effected under all conditions and in all positions of the pencil lead holder, the succeeding lead not playing any part during the various phases of feeding the lead in contact with the separate parts.

The parts ofthe leadA which come into engagement with the feed and retaining members being outside the body I and' thus visible, the user cannot therefore imagine that there'is a defective operation of the lead holder when there solely occurs an exhaustion of the reserve of leads.

By reason of the fact that the clamping jaws projecting from the body are formed by feed and retaining members, it is possible to make these of such a length that no permanent deformation is liable to occur. vThis great resiliency of the feedY and retaining members enables badly calibrated leads to be used, which represents a considerable advantage in comparison with known lead' holders.

It is to be observedthat a push applied to the end of the lead projecting from the jaws 5 and 6 tends to force the conical surfaces I2, I1 of the latter against the conical surface 1 of the opening which automatically produces a more powerful clamping of the gripping faces 20, 2I against the lead which prevents the latter-moving towards the interior of the body I. It will be understood that the movement of the cap may be limited either as above described, by the flange I6 coming into engagement with the end of the magazine tube 2, clinched on the guide'tube 4, or by the end of the body I coming into contact with the bottom of the cap. The free end of theV guide tube 4 may be provided with a conical ropening 22 or any other known means ensuring that the leads contained in the magazine enter the guide tube 4 one by one.

The slots provided between the limbs of the feed jaws 6 and in which are located the limbs of the retaining jaws 5, are preferably of a width smaller than thej leads to be used so that pieces of the leads, broken in the magazine 2 cannot leave the guide tube 4 and for example lodge themselves in the space 23 between the jaws 5 and 6 and thus obstruct the satisfactory operation of these.

It is to be pointed out that the clamping jaws 5 and 6 hold the lead II by means of their gripping faces 20 and 2| only. vSince these gripping faces have only small surfaces bearing against the lead, a perfectclamping of .the latter is thus assured even for non-calibratedy leads. The lead not being clamped. by means of a knife edge, there is no danger of it becoming sheared off,

It will be understood that modifications in the details may be made in the form of construction described above by way of example. For example the parts may be secured together in different manner and means for centering the mechanism in the interior of the body l may be provided which are different from those described.

I claim:

1. In a lead holder, comprising a tubular body provided with clamping jaws projecting from said body and also provided with a cap for producing the movement of the jaws, the combination of lead feeding means including certain of said clamping jaws and lead retaining means including other of said clamping jaws.

2. A lead holder according to claim 1, wherein said feeding means and said retaining means each include a set of jaws, both sets of jaws projecting from the body of the lead holder, a single seat cooperating with both said sets of jaws, both sets of jaws co-operating with the said seat to clamp the lead in its operative position.

3. A lead holder according to claim 1, comprising a magazine tube to which the clamping jaws of the lead feeding means are connected rigidly, said cap being mounted on said tube, said retaining means being frictionally engaged with said tube.

4. A lead holder according to claim 1, including means for limiting the movement o f the retaining means to a fraction of the total movement of said cap and of said feeding means.

5. A lead holder according to claim 1, comprising a guide tube, said retaining means being centred on said guide tube, said feeding means being secured to said guide tube, and means for respectively retaining said feeding means and ing a body having a conical seat therein, said said retaining means in their relative angular position. l

A lead holder according to claim 1, wherein said retaining means is provided with gripping jaws which tend to move away from a lead when in the released position.

7. A lead holder according to claim 1, includclamping jaws of the feeding means and said clamping jaws of the retaining means being provided with conical outer surfaces for cooperation with said conical seat, all of said clamping jaws having inner gripping surfaces for engagement with a lead, and all of said clamping jaws having outer conical faces for engaging with said conical seat, and a spring mounted in said body, said spring normally tending to press the outer conical surfaces of all of said jaws in said -conical seat to hold said lead in an operative position. Y

8. In a lead holder the combination comprising a tubular body having a tapered end, a cap slidably tted on the other end of said body, amagazine tube secured to said cap and tting within said body, a guide tube secured to said magazine tube, a flange on said guide tube adjacent said magazine tube, a spring located between said tapered end and said flange, a conical seat in said tapered end, a set of retaining jaws having resilient limbs slidably mounted on "said guide tube, a set of feeding jaws having resilient limbs rigidly secured to said guide tube, all oi said jaws having conical outer surfaces forvv cooperation with said conical seating, all of said jaws having internal gripping faces, the limbs of the feed jaws alternating with the limbs of the retaining jaws, and means for limiting the1 slid-

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