US2664071A - Pencil sharpener - Google Patents

Description

Dec. 29, 1953 G u H L 2,664,071

PENCIL SHARPENER Filed Sept. 6, 1950 3 Sheets-Sheet l will! I IIIIIII In venfar: v fmul m ,WM

Dec. 29, 1953 GUHL 2,664,071

PENCIL SHARPENER Filed Sept. 6, 1950 3 Sheets-Sheet 2 Invemor':

Dc. 29, 1953 A. GUH L 2,664,071

PENCIL SHARPENER Filed Sept. 6, 1950 3 Sheets-Sheet 3 Patented Dec. 29, 1953 UNITED STATES PATENT OFFICE- Claims priority, application Netherlands September 16, 1949 12 Claims.

My present invention relates to a pencil sharpener.

One of the objects of my present invention is to provide a pencil sharpener having a means for simultaneously gripping and feeding the pencil into the machine.

Another object of my present invention is to provide an electric motor to drive the pencil sharpener having a slip clutch connected thereto so as to prevent the breakage of any parts of the apparatus.

An additional object of my invention is to mount the gripping and feeding means on a plurality of symmetrically arranged guiding elements located near a spiral gear which actuates the gripping and feeding means.

The novel features which I consider as characteristic for my invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a partial cross section of a view of a pencil sharpening machine according to the invention taken from the side on which the pencil enters the machine and as viewed in the direction of arrow C of Fig. 2;

Fig. 2 is a cross section taken on the line A--B of Fig. 1, and looking in the direction of the arrows;

Fig. 3 is a cross section taken on the line D-E of Fig. 1, and looking in the direction of the arrows;

Fig. 4. is a view of the gripping elements as viewed in the direction of arrow F of Fig. 2;

Fig. 5 is a view of a fiat spiral gear as viewed in the direction of arrow F of Fig. 2;

Fig. 6 is a view of a feeding gear shown on an enlarged scale;

Fig. 7 is a sectional view of a control lever for stopping the operation of the apparatus;

Fig. 8 is a view of the stopping apparatus of Fig. 7, as seen in the direction of arrow G of Fig. '7

Fig. 9 is a sectional view taken along the line I-I-J of Fig. 7, and looking in the direction of the arrows;

Fig. 10 is a part of a machine stopping apparatus as viewed in the direction of arrow K in Fig. 11;

Fig. 11 is a plan view of the machine stopping apparatus shown in Fig. 10;

Fig. 12 is a partial sectional view of the motor and a slip clutch connected thereto;

Fig. 13 is a plan view of a two bladed knife;

Fig. 1 1 is an elevational view of the knife shown in Fig. 13;

Fig. 15 is an elevational view of another type of knife;

Fig. 16 shows a pencil point obtained by means of the knife shown in Figs. 13 and 14;

Fig. 17 is a sectional view of an elastic sealing member to protect the gearing of the machine from shavings;

Fig. 18 is a sectional view of another form of sealin means taken along the line L--M of Fig. 19; and

Fig. 19 is a sectional view taken along the line NO of Fig. 18, and looking in the direction of the arrows.

The pencil sharpening machine of my present invention comprises a frame 3 which has formed integrally therewith a circular rim 2 having a disc 3 fastened thereto, the disc 3 having a central conical opening 4 which is aligned with a corresponding opening 5 located in the frame I opposite to said opening 4. The opening 5 has a conical extension 6 integral therewith formed so as to correspond to a point of a pencil to be sharpened, whereby the pencil is properly supported within the machine.

Centrally arranged with respect to opening 4 and on the inner surface of the disc 3 is located a disc shaped boss which is provided on its surface, which is parallel to the inner surface of discs, with spiral gear teeth out therein, as shown in Fig. 5. A guiding plate 8 is freely and rotatably mounted about the shoulder of spiral gear l. The said plate 8 has located therethrough guide slots EB which have an arcuate shape and are arranged at a distance from the center of plate 8, as shown in Fig. 1. In spaced relation to the vertical inner surface of plate 8 is located a gear wheel in which is rotatably mounted and is aligned with plate 8. The gear wheel I9 is provided with gear teeth H which mesh with a pinion l2 which is connected by means of shaft l3 to a worm drive l4 which is operatively connected to drive shaft 55, which drives the sharpening tool It. The gearing by which gear wheel H3 is connected to drive shaft l5 provides a reduction in the speed of gear wheel H] as compared to the rotative speed of shaft 15 whereby the elements which grip the pencil, as will be explained below, rotate the pencil much slower than the shaft I5 is rotated. The gear wheel [0 has a flat flange l1-having a surface located adjacent to but spaced from plate 3 and parallel thereto. The flan e (i has three openings provided therein in which are pivotally mounted the pins it- In the space etween plate 8 and flange ll are located the gu ng segments or elel rents l9, ar ranged as shown in Fig. i, and to whichthe above mentioned pins it are Also joined to the guiding elements 59 are additional pins 9 which actuate the guiding elements it. Ihe elements l9 carry bearings 25! on each of which is located a feeding gear 2!, shown in Fig. 6, whose teeth are preferably so formed that they have ashar-p angular flat surface "2 extending in .theieeding direction and only have an involute configuration on the other side of the tooth from saidangular surface 22. As a result of the point shape of the teeth 22 the pencil can be effectively held so that it does not slip in the holding apparatus and will not be pushed out of the machine as a result of the cutting pressure of the cutting tool 56. The teeth .of the feeding gears '2 mesh with the ways between the teeth of spiral gear '2. As a result of this construction the pencil is more firmly held as the cutting pressure becomes greater in an axial direction of the pencil because the pressure on the teeth 22 is transmitted a radial direction upon the spiral gear teeth of spiral gear The three guiding elements iii are held together by sp ng 'rneans, such as for example, the coil spring 23 or any conventional spring means, so that the guiding elements is are urged in their idle position towards the central axis about which they are arranged.

As may be seen from Fig. 3, ring 24 which .is integral with plate 8 is engaged by a gripping means 25 which is provided with a slot. The said gripping means 25 is integral with a guiding lever 26 which carries at its outerfree .endan element 21 located at right angles thereto. The gu'ding lever 25 bears with its other free end ag st a stop .28 which is fixed to the frame I.

Rotatably and coaxially mounted with respect to plate 8 and gear wheel ii] is a ring-shaped disc 29. This disc 25 for reasons .of clarity .is not shown in Fig. 2 but may be seen in Figs. land 3. .As may be seen from Fig. 3, the disc .29 is retatably mounted about hollow element '30 formed integrally with the housing l. The ring-shaped disc as carries at an end thereof an operating lever B! by means of which the disc may be rotated about element 39 through a certain angle. The operating lever 3| carries on a pivot pin 32 a pawl 33 which is provided at its upper free end 3! with an inclined surface, which is adapted to bear against a corresponding surface on a stop 35 mounted on the housing I. The pawl 33 is urged outwardly by means of a leaf spring '53, or the like, against a stop (not shown). In the position shown in Fig. 1 the pawl 33 is engaged at its upper part with the guiding lever 26, 2?, the said guiding .lever 26, .2! being urged upwardly by means .of a spring 3.6.

According to a special form of the invention which is illustrated in Figs. 7 to 10, the machine comprises an automatic stopping mechanism which is released by the point of the pencil be ing sharpened. The stopping mechanism comprises a stop pin 37 which, as may be seen in D, is cut away at its lower portion and which is slidably mounted in sleeve 33 where .it bears against spring 39. .To the central portion of stop pin 3? is pivotally connected the control lever so. This control lever 48 is bifurcated at one end thereof, the said bifurcatedend engaging .an exhates the pencil which pushes moved through a certain justed.

At the lower end of stop pin is switch operating mem er which is pivot on pin The switch opt:

mounted lit a. l with its unnn. I point against the free end or con trol lever G3, shown in Fig. 9. As soon as the control lever distance by means 0 pin is (301" the switch 3 influence oh operating incinwhich has a curved s the pencil point, and the spondingly raised to a cer operating member r of spring whereby the on. her $51G rotated as to hr :the elect ical circuit to the driving or the l iachznc thereby :stop the driving of the machine. By means of the adjusting element is the stopping point of the machine can be regulated by adjusting the position of control lever In this, manner'it is possible to release the means [or stopping the drive of the machine at difierent grades of sharpness of the pe cils being sharpened.

l0 and 11 show an autcr iic for stopping the operation of the in nine according to which a link iii is pivot -y unto-d about pin 59 on gear wheel l2. b as against said linl: 51. The link 3. cutout per 53 through which a pin it passes, the said pin 56 being fixedly connected to ti plate 1. The l E! provided .atits free c with n extens having an inclined "a;

of movement of t e ext with this arranger:

ments illustrated in out portionor .detent of lin r 5 r obtains'when the guiding elem-e position of rest w ere they are diuvn by the spring 23 in'toware's the cent they arearrangecl. Thus, in elements shown in Fig. 10, the switch to operating element is att cherl ill be opened by the rotation of element 9 when no l is in the machine and the gui 1g elements not spread apart fr each other. n case, if the gui g el ments are sprc from each other, the link 5! is pivoted outwardly means of pin so that the extension does not come in contact with pin 57 and the shutting-oil switch is not actuated.

Fig. 12 shows the driving motor 58 whose shaft 59 is connected to the driving shaft l5 for the cutting tool by means of a slip clutch. The slip clutch can be of any known construction and the pressure thereof can be adjusted in any suitable known manner.

Itiis advantageous to'make the feeding apparatus reversible so that the machine can operate forwardly as well as rearwardly. This reversibility can be mechanically obtained by means of a changeable gear system, or the like, or it may be obtained electrically by reversing the poles of the electric motor. In this way it is possible to sharpen pencils which are so small that they are completely fed into the machine. and by reversing the direction of feeding the sharpened short pe cils can be fed back out of the machine.

Fig. 12 shows a battery connected to the field of motor 58 and a switch means 58' connected to the armature of the motor 58 for reversing the polarity thereof. When switch members 5811 and 5811 are in the position shown in Fig. 12, the current flows in one direction through the armature, and when the arm 5% is connected to the contact 580 and arm 58a is connected to the contact 58d current will fiow through the armature in a reverse direction.

As may be seen from Fig. 17, the gearing of the machine may be protected from shavings cut from the pencil by a sealing material which is made of a disc of soft rubber 65, which comprises an opening in its center through which the pencil 43 passes, and which is clamped at its outer end to a ring, for example, in the form of a circular ring 68 so that the rubber disc 65 together with the ring 6d may rotate with the pencil 48 in the housing 5. In order to effect this arrangement the ring so is guided by the end of sleeve 61.

The Figures 18 and 19 show another embodiment of a means for sealing oif the gearing of the machine from shavings out from the pencil. Brush hairs 6% are radially clamped within a flanged ring to of U-shaped cross section which extends over about 480 in such a way that the brush hairs (it may lie with their free ends on the outer surface of the casing of pencil 48. The flanged ring 68, which, as mentioned above, extends for more than a complete circle so that both of its free ends It! and H overlap with each other, as shown in Fig. 19, is mounted between the limiting pins l2 which are fastened to guiding elements is. The flanged ring 58 is of such a size that it is yieldingly and resiliently clamped between the limiting pins 12. Thus, the flanged ring 68 with the brush hairs 59, follow the position of the limiting pins 12 on guiding elements it so that the free ends of the brush hairs fit themselves to the respective diameters of the various pencils to be sharpened, and the circle of brush hairs can be opened and shut in a manner similar to the opening and shutting of an iris shutter.

The following is an explanation of the operation of the machine of my present invention:

When the operating lever 3!, shown in Figs. 1 and 3, is depressed, the ring shaped disc 29 is turned through a certain angle. As a result of this depression of operating lever 3| the guide lever 26, which is provided with the arm 21 located at right angles thereto, is held back by means of the spring 38 so that the clamping mechanism 25 which is fixed to the guide lever 23 can be turned with its slot and firmly grasp the ringshaped rim 24 of plate 8 in the slot which is then located in an inclined position; and in this way the rim 24 and plate 8 are carried along with the guide lever 25. In this manner the pins 9 of guiding elements [9 are moved outwardly in the guide slots 60 of plate 8 and the guide elements I9 and feeding gears 21 therewith are moved apart from each other. The clamping means for the pencil to be sharpened is thereby opened, and at this time a pencil 48 can b insorted through the conical opening 4 as shown in Fig, 2. During the rotation of ring-shaped disc 2% upon depression of operating lever 3!, the guide lever 26 bears against the stop 28 so as to limit the rotation of ring shaped disc 29. In this 6. manner, the slot of clamping means 25, which in effect forms a pair of clamping jaws, is turned in a direction Where it is again tangential to the rim 24 and the guide lever 26 is firmly held in this position of rest by means of the pawl 33. The plate 8 is thereby released and can freely rotate. In this manner the pins 9 of guiding elements [9 move towards the inner end of slot to under the influence of springs 23, and the gripping means [9, 20, 2| closes itself upon the pencil 28. At its lowest position of movement the operating lever 3i closes a switch (not shown) which permits current to be supplied to the motor 58.

The motor 58 now drives shaft 1 5 and the cutting tool It therewith by means of a slip clutch 59, and by means of the worm drive M, the motor drives shaft 13 and pinion i2 connected thereto so as to rotate gear wheel it which carries therewith the pins 18 of clamps i9, 28, 2| so that the said clamps rotate about the pencil axis X-Y, whereby the feeding gears 2! rotate in the ways of the spiral gear I, so that the pencil 68 which is firmly grasped in the teeth 22 of the gears 2i, is constantly moved forwardly in the direction of X towards Y While constantly rotating. The pencil point locates itself in the holding element 8, as shown in Fig. 2, and is sharpened by means of a rotating cutting tool, such as, for example, the two-bladed knife Hi.

After the operating lever 3! is released to the influence of spring 36 so as to again return to its original position, the right-angle portion 27 of guide lever 25 bears against stop 35 and simuh taneously limits the motion of the operating lever 31. In this position of the operating lever, the pawl 33 is again brought to its rest position by the sliding of its inclined end against the corresponding inclined surface of stop 3% so that it is raised out of engagement with guide lever 25. In this manner the guide lever 23 can again be pivoted upon the next actuation of operating lever 31 and in the above explained manner can again take the position where the clamps I9, 28, 2| are spread apart from each other so that the pencil with the completely sharpened point can be removed from the machine. It is also possible to remove the pencil from the machine while the machine is operating.

If it should happen that the operating lever 35 is depressed when there is no pencil in the conical opening a and when the clamps is, 2! are located inwardly toward the axis about which they are centrally arranged, then, as was described above, the plate 3 through the jaws of clamping means 25 is turned and with plate 8 the pin 54 is turned which is located in the detent 53 of link 5i when the clamps is, 253, 2| are in their said inward inoperative position. In this manner, the extension 5&3 of link iii moves into contact with pin 5? and operates switch op erating member 56 to stop the operation of the machine. Thus when the operating lever 3| is depressed but there is no penci in the 2" "inc the motor is shut off aft r having the gear wheel Iii less than one revolution. On the other hand, if the link 5i is moved outwardly means of guide elements it as soon as a per il is placed in the machine, the extension 2 link 5| in this operating position passes the pin 5'! and does not actuate switch operating member 56.

In the case where a great resistance to the running of the electric motor occurs because of particles of dirt in the gears or of other disturbances, the slip clutch located becannon tween electric motor and drive shaft l5, as shown in Fig. 12, will slip when a certain magnitude of turnin moment is obtained .so that the transmission of power between the drive shaft of motor 58 and the drive shaft i is broken. in this way the windings of the motor cannot be damaged by a current overload, accidents to the cutting 5001 and gear 3 produced by overloads are avoided. The pr -e of the slip clutch can be regulated way such as, for example, by adjusting the r pressure of spring 8| shown in Fig.

According to the invention is provided an adjustable, a. niatic machine-stopping mechanism which is by point of the pencil bein sharpened. This mechanism is illustrated in Y to 9. As soon as pencil '38 presses inwardly with respect to holding means '5 t Trough a certain distance, the incomplete pencil point pusl es against the control lever which raises stop pin 3? out of the path of movement of switch operating member so as to free member which then turns under the action of spring 49 and cuts oil the current supply to the motor so that the machine will At this time the arcuate segment of itch operatin member 45 raises the stop pin 3'. a furth r distance so that the end of control lever located a few mm. in advance of the p point so as to move ahead of the fcrwaro motion of the pencil point. in this manner i possible to move pencil further so that the sharpening of the point can be completed and is unhindered by control lever 40. This comple ion of the sharpening of the pencil points obtained by making use of the kinetic energy of the otor armature bv means of a flywheel, for exam l ive she.

!5 being connected to the motor armature is thereby turned so as to rotate the cutting tool and finish the sharpening of pencil point. By means of adjusting lever th control lever 40 can be set to any desired posi .on for shutting off the machine, so that, for era: iple, in the sharpening of writing or color pencils where a blunt point is desired the sharpening process can be automatically interrupted at any desired degree of sharpness of the point.

In Fig. 2 the cutting tool is shown to be a two bladed knife illustrate in Figs. 13 and 14 as having inclined straight cutting edges. The knife however can obviously have any suitable construction such as that of a milling cutter, for example. Knives having a small cutting angle are easiest to 1:" anuiacture and sharpen. It has been found to be especially suitable, in the operation of the machine, to rotate the cutting tool with a high speed of rotation which is somewhat more than 20,000 rotations per minute. In this manner, it is possible to obtain faultless points in penci s which are made of inexpensive wood and which preferably have soft marking materials located therein. The motor 58 need only be of a small size, and the pencil guiding and switching operating mechanic: is are all compactly constructed, so that the entire mac -ine is of a small size. The sharpening of the pencil takes only a few seconds so that the machine is not only suitable for pencil sharpening in ofiices but can also be used to sharpen new pencils in pencil manufacturing factories.

Instead of a cutting tool it is possible to use other shaving removing tools such as grinding wheels.

The machine has the advantage that it can sharpen all types of pencils of all usable diameters. .It'isusable for thin pencils such as those having a diameter of 3 mm., for example, and can also be used for color pencils having a diameter of about 13 mm. In order to sharpen the last mentioned pencils of large diameter, a form of knife which comprises a convexly curved or angularly shaped cutting edge 62 or 63, a shown in Figs. 'l-l and 15, has proved itself to be most suitable. Particularly, the angular cutting edge .63 has proved to be very satisfactory in performance, while also being very easy to sharpen. The cutting tools above described produce on thick pencils over 7 mm. in diameter an offset pencil point such as that illustrated in Fig. This has tr e advantage that to short but sharp and slender point 513 may be obtained in thick writing or drawing pencils such as color pencils, whereby labor and materials are saved and the pencil remains usable. By means of the same shaped knife, smaller sized pencils can also be sharpened in the same manner and with the same apparatus. It is possible to sharpen very small pencils .in the machine, whereby the usability of the machine is proportionally increased. The sharpening of the smallest pencils with faultless points can be obtained. with a machine constructed according to the invention, as distinguished from conventionally consructed sharpening machines. Also, the sharpening of the shortest practically usable pencils can be accomplished in the machine of my present invention so that it is not necessary to give up the use of mechanical devices in order to make a point on a short pencil.

A particular noteworthy characteristic of the invention is the combination of an automatic clamping means, which grips the pencil to be sharpened in a gripping apparatus so that the pencil is held. firmly and is simultaneously rotated and fed into the machine, with a sharpening apparatus in which the cutting tool rotates at a very high speed so that the marking material which rests freely in the pencil is pressed against the pencil casing by the cutting pressure and movement of the rotating cutting tool, which is opposed to the forward motion of the pencil. In this manner the breaking or tearing of a section of the marking material of the pencil being sharpened is safely avoided.

The new machine is fully automatic and is throughout characterized by the fact that it lends itself to many different types of uses and can 'fill many special requirements with a particularly simple and. suitable mechanism. Moreover, when the operation of the machine is for some reason faulty, the machine shuts itself oil without any accidents or disadvantage. Instead of the described driving eons, other driving elements may obviously be used to produce the same results produced by the described operation of the machine. In place of guiding ele-- ments I 9 which are provided with gears by which the pencil .is held and moved forwardly by the turning thereof, another means for gripping the pencil can be provided which itself sizuultane ously turns and moves axially so as to carry the pencil along therewith. In like manner the other described driving elements can be differently constructed by the use of suitably working parts without in any way changing the fundamental principle of the invention.

It will therefore be understood that each of the elements described above or two or more together, may also find useful application in types of sharpening machines other than that described above. 7

While I have illustrated and described the invention as embodi d in a machine for sharpening pencils, I do not intend to be limited to the details shown since various modifications and structural changes may be made without departing from the spirit of my invention.

Without further analysis the foregoing will so fully reveal the gist of my invention that others can by applying current knowledge readily adapt it for various applications without omitting features, that, from the standpoint of the prior art, fairly constitute the essential characteristicsof the generic or specific aspects of this invention, and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalents of the following claims.

What I claim as new and desire to secure by Letters Patent is:

l. A pencil sharpener, comprising, in combination, support means for supporting a pencil to be sharpened; rotatably mounted cutting means located adjacent said support means for cutting a pencil; turnable gripping means mounted on said support means for gripping a pencil to be sharpened and, upon turning, feeding the pencil to said cutting means to be cut thereby; and a single drive means operatively connected to said cutting means and said gripping means for simultaneously operating said cutting means and turning said gripping means to automatically feed a pencil to be sharpened to said cutting means, whereby the pencil to be sharpened may be automatically fed and cut.

2. A pencil sharpener, comprising in combinaticn, support means for supporting a pencil to be sharpened; gripping and feeding means mounted on said support means for sipping and feeding and rotating a pencil to he sharpened; rotatably mounted cutting means located adjacent said support means for cutting a pencil fed by said gripping and feeding means; and a single drive means operatively connected to said grippin and feeding means and said cutting means for simultaneously operating said gripping and feeding means and cutting means, whereby the penoil to be sharpened may be automatically fed and cut.

3. A pencil sharpener, comprising in combination, support means for supporting a pencil to be sharpened, said support means being located about a central axis; gripping and feeding means for feeding a pencil to be sharpened along said central axis, gripping and feeding means being mounted on said support means for rotation about said central axis; rotatably mounted cutting means located adjacent said central axis cutting a pencil to be sharpened; and a single drive means operatively connected to said cutting means and said grip-ping and feeding means for operating said cutting means and gripping and feeding means and for rotating the latter about said central axis so as to thereby rotate a pencil to be out simultaneously with the sharpening of the same.

i. In a pencil sharpener, in combination, support means for supporting a pencil to be sharpened, said support means bein located about a central axis; gripping and feeding means for feeding a pencil to be sharpened along said central axis, said gripping and feeding means being mounted on said support means for rotation about said central axis and said gripping and feeding means comprising a plurality of plate members mounted for movement toward and away from said central axis, resilient means operatively connected to said plate members for ur ing the same towards said central axis, and a plurality of gripping gears respectively mounted on said plate members for rotation about axes normal to said central axis; rotatably mounted cutting means located adjacent said central axis for cutting a pencil to be sharpened; and a single drive means operatively connected to said cutting means and said gripping and feeding means for operating said cutting means and gripping and feeding means and for rotating the latter about said central axis so as to thereby rotate a pencil to be cut simultaneously with the sharpening of the same.

5. In a pencil sharpener, in combination, at least two plate members symmetrically located about a central axis, said plate members bein mounted for movement toward and away from said central axis and being located in a plane normal to said central axis; resilient means operatively connected to said plate members for urging the same toward said central axis; at least two gripping gears respectively mounted on said plate members for rotation about axes normal to said central axis and parallel to said plane, said gripping gears being adapted to engage a pencil located along said central axis when said plate members are urged towards said central axis by said resilient means; and reversible drive means operatively connected to said gears for rotating the same in opposite directions, whereby, when said gears are rotated in one direction by said reversible drive means, a pencil may be automatically fed to be sharpened and, when said ears are rotated in a direction opposite to said one direction by said reversible orive means, an already sharpened pencll may be automatically removed from the sharpener.

6. In a pencil sharpener, in combination, at least two plate members symmetrically located about a central axis, said plate members being mounted for movement toward and away from said central axis and being located in a first plane normal to said central axis; resilient means operatively connected to said plate members for urging the same toward said central axis; at least two gripping gears respectively mounted on said plate members for rotation abut axes normal to said central axis and parallel to said plane, said gripping gears belng adapted to engage a pencil located along said central axis when said plate members are urged towards said central axis by said resilient means; and reversible drive means operatively connected to said gears for rotating the same in opposite directions, whereby, when said gears are rotated in one direction by said reversible drive means, a pencil may be automatically fed to be sharpened and, when said gears are rotated in a direction opposite to said one direction by said reversible drive means, an already sharpened pencil may be automatically removed from the sharpener, said reversible drive means comprising a spiral gear located in a second plane substantially parallel to said first plane and meshing with said grip-ping gears and transmission means interconnectlng said gripping gears and spiral gear for turning movement with respect to each other about said central axis.

'7. In a pencil sharpener, in combination, a stationary spiral gear formed with a central aperture passing therethrough and located along a central axis, the gear teeth of said spiral gear being located in a first plane normal to said central axis; support means located in a second plane parallel to said first plane and being mounted for rotation about said central axis; at least two gripping gears symmetrically located about said central axis and meshing with said spiral gear, said gripping gears being mounted on said support means for movement toward and away from. said central axis and for rotation about, axes normal to said central axis and parallel to said first plane; resilient means operatively connected to said gripping gears for urging the same towards said central axis; and drive means operatively connected to said support means for rotat ing the same about said central axis so as to thereby cause said gripping gears meshing with said spiral gear to rotate and feed a pencil gripped therebetween along said central axis.

8. In a pencil sharpener, in combination, a stationary spiral gear formed with a central aperturepassing therethrough and located along a central axis, the gear teeth of said spiral gear being located in a first plane normal to said central support means located in a second plane parallel to said first plane and being mounted for rotation about said central axis; at least two gripping gears symmetrically located about said central axis and meshing with said spiral gear, said gripping gears being mounted on said support means for movement. toward and.

away from said central axis and for rotation about axes normal to said central axis and parallel to asid first plane; resilient. means opera,- tively connected to said gripping gears for urging the same towards said central axis; and reversible drive means operatively connected to said support means for rotatin the same about said central axis so as to thereby cause said gripping gears meshing with said spiral gear to rotate and feed a pencil gripped therebetween along said central axis when said drive means rotates said support means in one direction about said central axis, and so as to cause said. gripping gears to move an already sharpened pencil out of the sharpener when said drive means rotate said support means in a direction opposite to said one direction.

9. In a pencil sharpener, in combination, a stationary spiral gear formedwitha central aperture passing therethrough and located along a central axis, the gear teeth of. said spiral gear being located in a first plane normal to said central axis; support means located in a second. plane parallel mounted for rotation about said central axis; at least two gripping gears symmetrically located about said central axis and meshing with said spiral gear, said gripping gears being mounted on said support means for movement toward and away from said central axis and for rotation about axes normal to said central axis and parallel to said first plane; resilient means operatively connected to said gripping gears for urging the same towards said central axis; drive means operatively connected to said support means for rotating the same about said central axis so as to thereby cause said gripping gears meshing with said spiral gear to rotate and feed a pencil gripped therebetween along, said central axis, said drive means comprising an elongated drive shaft and Worm gear means interconnecting said drive shaft to said first plane and being 12 and support means for rotating the latter at a lesser rate of speed than that at which said drive shaft rotates; and blade means mounted on said drive shaft for cutting a pencil fed by said gripping gears.

10. In a pencil sharpener, in combination, a stationary spiral gear formed with a central aperture passing therethrough and located along a central axis, the gear teeth of said spiral g ar being located in a first plane normal to said central axis; support means located in a second plane parallel to said first plane and bein mounted for rotation about said central axis; at least two grippin gears symmetrically located about said central axis and meshing with said spiral gear, said gripping gears being mounted on said support means for movement toward and away from said central axis and for rotation about axes normal to said central axis and parallel to said first plane; resilient mean; operativel'y connected tosaid gripping gears for urging the same towards said central axis; dr ve means operatively connected to said support ans for rotating the same about central a; s so as to thereby cause said gripping gears meshing with said spiral gear torotate and feed a pencil gripped therebetween along said central axis, said drive means comprising a motor and an elongated drive shaft driven thereby and worm gear means interconnecting said drive shaft and support means for rotating the latter at a lesser rate of speed than that at which said drive shaft rotates; blade means mounted on said drive shaft for cut ting a pencil fed by said gripping gears; and slip clutch means mounted between said motor and drive shaft for preventing operation of the pencil sharpener under overload conditions.

11. A pencil sharpener as defined in claim 3 and wherein said support means comprises a stationary plate formed with an aperture located about said central axis and adapted to have a pencil to be sharpened extending therethrough, said plate having an annular projection fixed thereto; and a guiding ring mounted on said annular projection for rotation thereabout and being connected to said gripping and feeding means to support the same for rotation about said central axis.

12. A pencil sharpener as defined in claim '7, and wherein said gripping gears have teeth each of which is pointed and provided on one side with a curvature corresponding to the shape of the groove in the spiral gear.

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