US2266269A - Pencil sharpener - Google Patents

Description

Dec. 16, 1941. E. G. ROMEISER PENCIL SHARPENER Filed Oct. 21, 1938 2 Sheets-Sheet l Dec. 1 6, 1941. E. G. ROMEISER 2,266,269

PENCIL SHARPENER Filed Oct. 21, 1938 2 Sheets-Sheet 2 Patented Dec. 16, 1941 UNITED STATES PATENT OFFICE PENCIL SHARPENER Ernest G. Romeiser, Union City, Ind.

Application October 21, 1938, Serial No. 236,339

4 Claims.

My invention relates to pencil sharpeners of the motor driven, automatic type, and aims to provide certain improvements in the structure, arrangement, mode of operation, durability and general efficiency of these devices.

It has heretofore been proposed to drive the cutting members of a rotary pencil sharpener by electric motor means controlled by a switch which is operable automatically on insertion and withdrawal of the pencil. The best of these machines of which I am aware have suffered from certain inherent disadvantages which the present invention seeks to eliminate.

Among the principal objects of the present invention are: the provision of an' improved switch and a novel mounting and mode of connection with the manipulating means for the switch, so that this vital element of the machine will render trouble-free service throughout and even beyond the life of the other parts of the organization; a novel arrangement of the apertured means at the front of the machine, permitting an unusually short length of pencil to be inserted into engagement with the cutters while a sufiicient portion of such short length projects from the machine to enable the same to be held conveniently by the hand of the user, so that unprecedentedly short pencil stubs may be readily sharpened; to separate the electric motor from the cutters by a substantially dusttight partition, so that fouling of the motor parts by dust and cuttings from the pencils is prevented; to protect the switch points from the same and other kinds of contamination; to simplify the construction while retaining the advantages of the prior art types of machine and eliminating the deficiencies and disadvantages thereof; and in general to produce a neat, compact, inexpensive, durable and highly efficient machine for sharpening pencils and the like.

In the accompanying drawings I illustrate certain embodiments of the invention at present preferred by me since they have been found to give satisfactory and reliable results in attaining the objects hereinabove stated. These embodiments and the description of them hereinafter are selected, however, merely to illustrate the invention, and it is to be understood that the invention may be otherwise incorporated without departing from its spirit or from the scope and purview of the appended claims.

In the drawings, wherein like reference characters designate similar parts in the several views,

Figure 1 is a side elevational view of the operating parts, with the housing shown in vertical, longitudinal section;

Fig. 2 is a cross sectional View taken along the line 22 of Fig. 1;

Fig. 3 is a detail side elevational view of the operating parts, showing a modification of the switch operating means of Figs. 1 and 2;

Fig. 4 is a front elevational view of the switch operating means of Fig. 3, being taken along the line 4-4 of Fig. 3; and

Figs. 5, 6 and 7 are detail front elevational views, analogous to that of Fig. 4, showing three further modifications of the switch operating means.

Referring to the drawings, it will be understood that in preferred embodiments of the invention the mechanisms shown in Figs. 3 to '7, inclusive, will, in each case, be associated with the parts not shown in those figures but appearing in Figs. 1 and 2. Moreover, in such preferred embodiments of the forms of the invention illustrated in Figs. 5, 6 and 7, the relatively long switch mountin shaft shown in Fig. 3 may be used.

In the drawings, the reference numeral I designates a base plate of metal or the like, and 2 indicates generally a housing or cover mounted on the base as by bolts 3. The frame of the operating parts of the device includes a rear frame plate 4 and a front frame plate 5 rigidly assembled in spaced relation as by a pair of comparatively long bolts 6, each surrounded by a spacing sleeve I. In this way the interior of the housing is divided into a front compartment 3 and a rear compartment 9.

As shown in Fig. 1, the rear frame plate 4 extends from the base to the roof of the housing or cover, and from side wall to side wall of the housing. Preferably the housing plate 4 is received in a channel l0 extending completely around the interior of the housing, and between the base of the channel and the edge of the plate 4 a ribbon or the like of soft packing material II is interposed, so that the plate 4 forms a substantially dust-tight partition between the compartments B and 9.

An electric motor I2 is mounted on the rear frame plate 4 and positioned in the compartment 9. This mounting may be accomplished in any convenient manner, but I prefer to support the motor from the plate 4, independently of the base and housing. In the illustrated embodiment the armature shaft l3 of the motor is journalled in the plate 4 and carries at its opposite end a pinion l4 meshing with a gear [5. This gear through the upper part of the compartment 9. A familiar type of pencil sharpener assembly is mounted between the plates 4 and 5 in the upper part of the compartment 8 and in alignment with the drive shaft l5. As shown, this assembly comprises a plurality of cylindrical cutters if! each having a plurality of spirally disposed cutting edges. The cutters are mounted on forwardly directed pintles journalled in a spider IS. The rear end of the spider penetrates an internally toothed ring gear with which pinions 2| fast on or integral with the shafts of the cutters is are engaged. The ring gear 20 is mounted fast in or on the plate 4 and the ends of the spider H! are journalled for rotation in the plates 4 and 5. The rear end of the spider I9 extends through the plate 4, preferably making a substantially dust-tight fit therewith, and terminates in a socket 22, with which a square or other polygonal end of the drive shaft l5 makes a driving connection.

The cutter assembly shown in Fig. 1 and hereinabove described, is well known and is deemed to require no further description. It will be recognized that when the spider I9 is rotated by the drive shaft IS the cutters l8 undergo a planetary movement, so that their spirally disposed cutting edges have a cutting or sharpening effect or the like on a pencil inserted between them through an axial opening in the forward end of the spider. Any other type of cutting or pencil sharpening assembly may be substituted in the construction, since the cutting assembly itself is not the subject of the present invention.

The front frame plate 5 is provided with an aperture 23, serving as a pencil receiving opening, aligned with the axis of the cutter assembly. The housing front plate 24 is similarly apertured in alignment with the opening 23 and the cutter axis, and this housing front plate 24 is positioned immediately in front of and close to the front'frame plate 5.

The switch controlling the motor and the mounting means by which the circuit to the motor is closed automatically when a pencil is inserted and automatically opened when the pencil is removed form an important part of the invention and will now be described.

In the embodiment illustrated in Figs. 1 and 2 lead wires 25 to the motor enter the housing through an insulating bushing in the rear wall thereof and terminate in a pair of insulated connector blocks mounted on a shelf 26 bracketed in the compartment 9 on the rear frame plate 4 and suitably insulated therefrom. Connections 21 extend from the connector block through the plate 4 to a mercury switch 23 mounted in a clip 29 positioned in the front compartment 8, behind the front frame plate 5. This clip 29 is supported by a lever 30 of peculiar but generally bellcrank shape, pivotally mounted as at 3| on and close to the forward face of the front frame plate 5. The operating arm of the lever 30 is disposed about the opening 23 in the plate 5, and a spring or equivalent means 32, reacting between the switch carrying arm of the lever and an abutment on the plate 5 biases the lever so that its operating arm normally partially closes the opening 23, all as best shown in Fig. 2. The portion of the lever which normally partially closes the opening 23 may be formed with a slight twist or otherwise beveled as at 33 to provide a globule to shift by gravity to bridge and unbridge aeeaeee cam surface which will cause the operating arm of the lever to be displaced when a pencil is inserted through the opening 23. This rocking movement of the lever against the action of the spring 32 shifts the switch 28 from its open circuit position shown in Fig. 2 to its closed circuit position. It will be understood that the switch which I prefer to use is the type comprising an exhausted glass envelope containing spaced electrodes 34 and a globule of mercury 35. The switch is mounted for rocking to one side or the other of a horizontal plane to cause the mercury the electrodes 34.

Electrical connections 35 extend from the connector block or shelf 26 to the motor, and the circuit is such that the motor and switch are in series, so that energization of the motor is controlled by the switch.

It will be noted that the spacing between the front frame plate 5 and the housing front plate 24 is extremely small. This close spacing is made possible by the fact that the switch 28 is mounted behind the frame plate 5, being accommodated by a notched or cut-out edge portion at the top of the plate, as shown in Figs. 1 and 2. The space between the plates 5 and 24 need be sufficient only to accommodate the metal of the lever 35, including its twist or beveled portion 33, and since this lever may be made of thin gauge stock, so that it is in effect a blade, and the beveled portion need not extend outwardly any appreciable distance, and indeed may penetrate the plane of the plate 24 through the pencil receiving opening therein, it will be appreciated that the spacing between the plates 5 and 24 may be very close. c

The cutting surfaces of the cutters l8 are positioned immediately behind and close to the plate 5. This fact, in combination with the close spacing between the plates 5 and 24, brings the cutting zone of the cutters extremely close to the outer face of the housing front plate 24. This enables pencils of unusually short'length to be sharpened. 7

In the best prior art pencil sharpeners of which I am aware the automatic switch operating means occupies considerable space between the cutters and the front of the housing, so that a considerable length of pencil must extend between the cuttingzone and the portion which must project from the housing to be grasped by the fingers of the operator. Such devices obvifously cannot be used to sharpen very short stubs of pencils, so that an appreciable portion of each pencil is wasted or must be sharpened by a knife or the like. Many persons prefer to use short pencil stubs, with or without a holder therefor, and such short stubs are necessarily used in certain drafting instruments, as for example pencilpointed compasses: The device which I have invented and hereinabove described in one form of embodiment can be used to sharpen such stubs down to the last inch or two of their length, and this I deem to be a valuable and novel feature of the machine.

The front frame plate 5 is best made short enough in its vertical dimension to leave an opening below its lower edge in the lower zone of the front compartment 8. A drawer 31 may be provided in this opening for receiving the shavings and dust from the cutter assembly.

Figs. 3 to 7 inclusive illustrate modified embodiments of the switch mounting and operating assembly, allof them affording the advantages of close spacing between the cutting zone and the front plate of the housing, as has been explained above.

In Figs. 3 and 4 I show a rack bar 40 mounted in slide bearings 4| on the front face of the plate 5 and engaged with a pinion 42 fast on a shaft 43 which extends to the rear of the plate 5, conveniently through a bearing in the plate 4 to carry the clip 29 of the switch 28 in the compartment 9, above the motor and drive shaft IS. The lower end of the rack is substantially right-angularly directed and cammed or beveled and a spring 44 urges the cam portion into partial obstruction of the opening 23. It will be evident that insertion of a pencil will have the effect of lifting the rack bar, rotating the pinion and shaft 43 to rock the switch to close the circuit through it, while Withdrawal of the pencil will enable the spring 44 to rock the switch oppositely, so as to open the circuit.

In Fig. 5 the operating arm 45 of the lever 46 is formed as a segmental rack meshing with the pinion 42 and the assembly is otherwise as shown in Figs. 3 and 4, so that the switch 28 is similarly rocked to closed and open position by insertion and withdrawal of a pencil.

In Fig. 6 the operating arm 41 of the lever is notched to receive a crank arm 48 formed on the shaft 43, the parts being otherwise as shown in Figs. 3 and 4, so that the same operation thereof results from insertion and withdrawal of a pencil.

In Fig. 7 the sliding or reciprocating means 49 is notched at 50 to engage the crank arm of the shaft 43 on which the switch 28 is mounted, the parts being otherwise as shown in Figs. 3 and 4, so that insertion and withdrawal of a pencil will raise and lower the means 49 to close and open the circuit through the switch.

An important advantage results from the use of a mercury switch. It will be observed that the switch may be located in the cutter compartment, as shown in Figs. 1 and 2, or outside this compartment, as shown in Figs. 3-7. Wherever located, the mercury switch is protected by its glass envelope from short circuiting by an accumulation of foreign matter between its contact points. In the best prior art devices with which I am acquainted, ordinary exposed contact types of switches are used, and these switches are frequently short-circuited by dust, cuttings, and particularly particles of graphite thrown out by the cutters. It will be evident that regardless of where the mercury switch of my invention is located in the machine, no short circuiting can occur. Moreover, sparking at the switch points is also eliminated along with the resulting wear and deterioration of the points and the danger of fire resulting from sparking in the presence of oiled running parts, generally coated with a deposit of wood shavings.

The general arrangement of the parts is deemed to be particularly compact and eflicient. It will be observed that within the small compass of the housing 2 there are contained the motor, transmission, cutter assembly and shavings dump. These several parts are arranged close together, so that no space is wasted and the entire device is small and of neat over-all shape.

The construction has advantages other than those hereinabove indicated as will be appreciated by those skilled in the art. Variations and departures from the specific construction shown and explained will readily suggest themselves, but all such modified embodiments, to the extent that they are within the spirit of the invention as pointed out in the appended claims are to be deemed within the scope and purview thereof.

I claim:

1. In a pencil sharpener mechanism of the class wherein insertion of a pencil into the casing enclosing the mechanism operates to close a circuit to a motor driving a cutting device and Withdrawal of the pencil operates to open the circuit, the combination of a switch for controlling said circuit comprising a sealed envelope within the casing, adjacent to the cutting device and in the path of cuttings thrown therefrom, mounted for rocking movement, electrodes in the circuit and spaced apart in the envelope, a conductor movable into and out of bridging relation with the electrodes on rocking movement of the envelope, and an operating lement having a portion connected to the envelope and another portion mounted for movement by the pencil on insertion and withdrawal whereby such movement rocks the switch envelope.

2. In a pencil sharpener mechanism of the class wherein insertion of a pencil into the casing enclosing the mechanism operates to close a circuit to a motor driving a cutting device and withdrawal of the pencil operates to open the circuit, the combination of a front plate narrowly spaced inwardly of an apertured wall of the casing and mounting the cutting device closely adjacent thereto, whereby a short stub of a pencil may be inserted through the aperture in the Wall and into cutting relation with the cutting device, a switch controlling said circuit comprising a sealed envelope mounted for rocking movement within the casing adjacent to the cutting device and in the path of cuttings thrown therefrom, electrodes in the circuit and spaced apart in the envelope, a conductor movable into and out of bridging relation with the electrodes on rocking movement of the envelope, and a switch operating element engageable by the pencil for controlling the motor comprising a thin blade mounted flatwise on the plate and slidable in the narrow space between said plate and said wall for rocking the envelope responsive to insertion and withdrawal of the pencil, whereby a short stub of a pencil may be inserted through the aperture in the wall and into cutting relation with the cutting device.

3. In a pencil sharpener mechanism of the class wherein insertion of a pencil into the casing enclosing the mechanism operates to close a circuit to a motor driving a cutting device and Withdrawal of the pencil operates to open the circut, the combination of a front frame plate narrowly spaced inwardly of a wall of the casing having a pencil-receiving opening and mounting the cutting device closely adjacent thereto, and a switch operating element comprising a thin blade mounted flatwise on the plate and slidable in the narrow space between said plate and said wall and having a beveled portion penetrating said opening for engagement by the pencil for controlling the motor, whereby a short stub of a pencil may be inserted through the opening in the wall and into cutting relation with the cutting device.

4. In a pencil sharpener mechanism of the class wherein insertion of a pencil into the casing enclosing the mechanism operates to close a circuit to a motor driving a cutting device and withdrawal of the pencil operates to open the circuit, the combination of a front frame plate narrowly spaced inwardly of a wall of the casing having a pencil-receiving opening, a bearing in said plate inserted through the opening in the wall and into cutting relation with the cutting device, and a mercury switch operatively connected to the switch operating element to be rocked thereby on 5 insertion and withdrawal of a pencil through said opening.

' ERNEST G. ROMEISER.

Images