US2541401A - Mechanical eraser - Google Patents

Description

Patented Feb. 13, 1951 UNITED STATES ATENT OFFICE l Claims.

My invention relates to erasers for use generally in deleting marks, lines, letters and similar characters from typewritten and other sheets and from drawings. Specically, the invention pertains to a mechanical eraser of a type wherein a long slender strip of eraser material is enclosed in a long barrel from which it may be intermittently fed as necessary to present additional eraser material as previously extended material is worn oli" in use.

Among the more important objects oi the invention are the following:

To provide an eraser of such size and shape that it may be held in the manner of a pencil and used with substantially the same accuracy as a pencil;

To provide an eraser in which the erasing material is presented to the work in a relatively thin ribbon-like form so that it may be used to erase small areas such as individual characters in typewritten lines or individual lines adjacent other lines in drawings;

To provide an eraser which is particularly adapted to erasing single characters of typewritten material withouts removing the work` from the typewriter and, if desired, without rotating the platen to move the work up into a more accessible position;

To provide an eraser in which practically all the erasing material may be eiciently used for the purpose of erasing without the necessity of cutting away and discarding or rubbing off portions of the material to keep the working edge sharp;

To provide an eraser from which the eraser material may be conveniently and rapidly extended as desired by a simple reciprocating action of a slider;

To provide an eraser in which the strip of eraser material is held rmly near the point of use so that elastic deflection is minimized;

To provide an eraser into which refills may be readily inserted with a minimum of difliculty and delay and to provide an eraser in which various grades of erasing material may be interchangeably used;

To provide an eraser in which the eraser material, except for the small exposed portion currently available for use, is completely enclosed and protected from accumulation of dirt, grease, perspiration, and other objectionable deposits; and

To provide an eraser incorporating a brush disposed on the end opposite the erasing end in (Cl. 12B- 36) a form most convenient for cleaning erased materiai from the work.

Further objects of the invention will become apparent from the following specification and the drawing, which is intended for illustration purposes only, and in which:

Fig. 1 is a plan view of my improved mechanical eraser; y

Fig. 2 is a side view of the same;

Fig. 3 is an enlarged fragmentary longitudinal sectional view of the forward end of the eraser, taken on line 3 3 of Fig. l, but showing the eraser material as partially worn away;

Fig. 4 is a view similar to Fig. 3 showing the feeding slide as moved forwardly to project a new portion of the eraser material from the end of the device;

Fig. 5 is a similar view showing the eraser material as havingbeen fed forwardly and the feeding slide returned to inoperative position;

fig. 6 is an enlarged cross-sectional View, taken on line E-$ of Fig. 5; and

Fig. 7 is an enlarged cross-sectional View, taken on line l-l of Fig. 5.

Referring to the drawing in detail, the improved eraser consists of four parts, namely, a barrel or holder I 0, a slider or feeding element l l, a strip of eraser material l2 and a brush assembly i3.

The holder I6 consists of a tube of substan- `tially rectangular cross section having its corners rounded as shown in Fig. 6. The holder il) may be made from sheet metal struck up in a suitable die and folded to the required shape, after which the lateral edges of the stock may be secured in overlapping engagement as shown in Fig. 6. At its forward or muzzle end, the narrow sides of the holder Ill are slit as shown at l5 so as to provide upper and lower resilient tines or jaws i6 and Il. Rearwardly of the jaws i6 and il, the wider top and bottom portions of the holder it are stamped with U-shaped cutouts il", thus providing resilient tongues or retaining pawls i8 and i9 which curve inwardly as shown in Fig. 3. Preferably the holder member I@ is provided with a series of ribs 2li which serve as ringer grips to prevent slipping of the holder between the iingers during an erasing operation or during feeding of the eraser material in the manner to be later explained.

The brush assembly i3, referred to above, ccmprises a sheet metal cup 22 in which the inner ends of a group of bristles 23 are clamped. The brush is applied to the rear end of the holder lll by merely inserting the cup thereinto. As before indicated, the brush is used for the purpose of cleaning erased material from the work, and it will be apparent that it also serves to cover the rear end of the holder so as to exclude dust and other foreign matter from the interior of the holder.

The slider or feeding element II consists of a rectangular tube having rounded corners and of a size adapting it to slide on the holder I at the forward end thereof. The slider may be made by blanking, embossing, and forming a sheet of thin metal into rectangular cross section, the lateral edges of the sheet being resistance-welded along the lapped seam. At the forward or muzzle end of the slider, the material is doubled or hemmed inwardly to form inwardly projecting lips 25, thus reducing the size of the opening at the forward end of the slider and reinforcing the thin flat-walled tube to provide greater stiffness. At the mid portion of the slider, its upper and lower sides have U-shaped cut-outs, thus providing resilient feeding pawls 26 and 21 which curve inwardly. Rearwardly of the pawls 26 and 21, the upper and lower sides of the slider are embossed to provide transverse ribs 28 which serve as finger-grips when the slider is moved longitudinally.

After the holder I and slider II have been fabricated, they are assembled by sliding the slider onto the muzzle end of the holder. During this movement, the pawls 26 and 21 are deiiected outwardly by the jaws I6 and I1 and the upper and lower sides of the holder Ii) until they pass the edges of the cut-out portions I1 in the upper and lower sides of the holder, at which time they spring inwardly into the cut-out portions I'i. The slider II may be pushed further onto the barrel I3 until it is finally restrained by Contact of the inwardly projecting lips against the forward ends of the jaws i6 and I1. The slider II is shown in substantially this position in Fig. 5, and it will be noted that engagement between the relatively rigid lips 25 and the readily deiiectable jaws I6 and I1 forces the latter toward i each other. After the slider l i has been thus assembled on the barrel or holder I, the pawls 26 and 21 act to prevent removal of the slider due to the fact that their forward ends move under the forward edges of the cut-outs I1.

The eraser strip I2 is preferably made in parallelepipedal form with rounded or chamfered corners to give clearance inside the barrel Il). Rubber-base eraser stocks are commonly available in different types and grades for different kinds of work. For example, when erasing typed characters from hard bond papers, a hard and highly abrasive material is desirable; for erasing typed or carbon paper characters from soft bond or sulphite papers, a medium hard eraser stock with moderate abrasive qualities may be used; and for erasing pencil lines, a medium soft stock having mild abrasive qualities is suitable.

With the various parts of the complete device now described and with the slider II assembled on the barrel Iii, the loading and feeding operations are performed as follows:

To insert an eraser strip I2, the brush assembly I 3 is first removed from the rear end of the barrel IEJ, and the slider Il is moved forwardly on the barrel la to the limiting position determined by contact of the pawls Z6 and 21 with the edges of the cut-outs I1. A length of eraser stock I2 is inserted into the rearward end or breech of the barrel I6 in which it slides freely until its forward end engages the inner surfaces of the tongues I8 and I9. Additional pressure exerted against the rearward end of the strip i2 forces it between the tongues I8 and I@ so that the forward end of the strip deiiects and passes between these tongues until it comes into contact with the inner surfaces of the pawls 26 and 2i'. Due to the relatively poor columnar qualities of the eraser strip I2 under compression loads, and due to the tendency of the material to deflect into frictional contact with the inner walls of the barrel IG, it is usually impossible to extend the front end of the strip beyond the pawls 26 and 21 by applying further force against the rearward end of the strip.

At this time the barrel is held in one hand with the thumb and foreiinger exercising a firm grip upon the ribs 20, and the slider II is grasped between the thumb and forefinger of the other hand and pulled rearwardly along the barrel until light resistance to further movement is caused by contact of the inwardly turned lips 25 against the jaws I6 and i1. During this rearward movement of the slider il, the forward tips of the tongues I8 and i9, embedded in the eraser` strip i2, restrain the latter from rearward motion which might be caused by contact of the tips of the pawls 26 and 21 against the strip I2.

With the slider II in retracted position, it is then firmly gripped between the thumb and foreiinger of the operator so that the pressure applied to the outer surfaces of the pawls 26 and 21 forces the latter toward one another, and the tips of these pawls embed themselves in the flat upper and lower faces of the strip I2. With the pawls 26 and 21 thus rmly gripping the strip i2, pressure is maintained and the slider II is moved forwardly to the position shown in Fig. 4 where further movement is limited by contact between the pawls 26 and 21 and the edge of the vcut-out I1. This forward movement of the slider II will carry the eraser .strip forward a distance approximately equal to that traveled by the slider itself. Pressure on the pawls 26 and 21 is then diminished so that the tips of these pawls are no longer embedded in the strip I2 and the slider is pulled back again to the position shown in Fig. 3. Pressure is then re-applied to the pawls 26 and 21 which re-embed themselves in the strip and the slider is again moved forwardly to the limit of travel. Three or four such successive reciprocatory cycles will feed the strip forward-ly until it projects beyond the end of the slider as shown in Fig. 4.

The slider is then pulled back onto the `barrel firmly into the position of Fig. 5 and in this position pressure of the inwardly projecting lips 25 on the outer surfaces of the jaws I6 and I1 causes the latter to squeeze the strip i2 very firmly. The brush assembly i3 is inserted into the breech end of the barrel i6, and the completely assembled eraser is ready for use.

With eraser stocks such as previously referred to and having the approximate dimensions shown in the drawing a length of stock equal to about twice the thickness of the strip itself is left exposed when performing the initial loading operation. The eraser may be used until the projecting portion is worn off to a Alength of about le", or somewhat less than the thickness of the strip, as shown in Fig. 3. When it is desired to feed .out additional eraser stoclgwthe slider I'i is firmly rgrasped as explained before with inwardly deiiecting pressure exerted on the pawls 26 and 21 and moved to the position .shown in Fig. 4. A single such stroke will ordinarily feed out enough eraser stock to replace that worn off and the slider Il may then be returned to the gripping position of Fig. 5. If by any chance a single stroke of the slider does not feed out as much stock as desired, supplementary strokes may be employed.

As more and more eraser material is successively extended and worn off, the strip I2 is progressively moved forwardly until the tips of the pawls 2S and 2l push against the rearward end of the strip. This is the limit of "automatic feeding, and at this time the remaining strip of eraser` stock is approximately 1/2 long. As they extended end of this remaining portion is worn down, some additional material may be extended by pulling on the exposedv end, so that only a sufficient length ofA material to permit rm grip by the jaws i6 and I1 (approximately 13;")1 finally remains as unusable Waste.' It will bey seen that this permits up to 95% utilization of the eraser material.

f it is desired to change the load from one type of eraser stock to another, this may be easily done in the following manner: With a normal projecting length of eraser material extended from the muzzle, they slider Il is moved back and frth a few times to increase this length and brought to rest in a position near the forward position. Pressure of thumb and forefnger is then released, with the result that the pawls release their grip upon the eraser strip. The projecting end of the strip is then grasped and the entire strip withdrawn from the barrel. The substitute eraser material may then be loaded and fed into position for use as previously de- 'f scribed.

in contrast to prior erasers, the eraser design has marked advantages. The slender but rigid metallic barrel gives the typist a firm grip which permits manipulation of the short extended portion of eraser stock in contact with the work with precise pressure and accuracy. Both longitudinal and transverse erasing operations may be performed with relative ease and precision. By far the most common typing error is one of a single letter in a word and since the thickness of the extended portion (.094") of the eraser is of thesa'me order as the spacing of pica and elite types, transverse erasure of single characters is accomplished with accuracy and ease. As the eraser is held in one particular position relative to the work for a few strokes and eraser material is Worn off, relatively sharp corners are produced on the projecting piece of stock and with a change in grip on the barrel these corners may then be utilized to furnish small areas for further accurate erasing operations. `As these corners, in turn, wear down, others are produced for further small areal erasure. With a little practice a typist can perform numberless consecutive erasing operations with great accuracy without any necessity for sharpening the eraser and with full utilization of the material for constructive erasing. f

When it is necessary to erase at or near the bottom of a typed page, under such conditions that it would be undesirable to move the platen, the eraser of ymy design is very superior. By moving the typewriter carriage to one side or the other, the typist can bring the error into view, and by taking advantage of the slenderness, length and rigidity of my eraser she may erase either longitudinally or transversely. Since the platen is not rotated, register is intact and erased areas may be immediately re-typed. The fact of my thatl the'present eraser may be usec'l'vv'vithv great accuracy largely eliminates the need for using an erasing shield, and in turn eliminates the smudging difficulty previously pointed out. The facts that in the eraser of my design the hands never come into contact with the eraser material and the strip of material is completely enclosed except for the short projecting section made available for current use result in having very clean and grease-free material at the point of application to the work, with consequent elimination of smudging due to foreign matter.-

In addition to the manifest advantages of the eraser of my design for use on typewritten material, it is very useful for erasure of hand Written or hand drawn pencil or ink lines. When used with certain eraser stocks, previously mentioned, the improved device will erase ink lines with great accuracy, and when loaded with other material it makes an excellent tool for draftsmen. Gn the drafting board, as Well as on typewritten material, an erasing shield may leave marginal smudges; since my eraser may be used with extreme accuracy without a shield, this diiiiculty is eliminated. Not infrequently a draftsmany will inadvertently draw a full or solid line where a l broken or dotted line is called for. With ordinary equipment, the corrective procedure is "to completely erase the incorrect line and re-draw it; With the eraser of my design, it is only necessary to erase short lengths of line at intervals as desired, thus producing the required interrupted line. Since the instrument can be handled with substantially the rapidity and accuracy of a pencil, an operation of this sort can often be carried out with a material saving of time over the ordinary method.

While I have herein shown and described the improved eraser device as embodied in a preferred form of construction, by way of example, it will be apparent that various modifications might be made in the structure without departing from the spirit of the invention. Consequently I do not wish to be limited in this respect but desire to be afforded the full scope of the appended claims. y y

I claim as my invention:

1. An erasing device, including:L a tubular holder of substantially rectangular cross section; an eraser strip of similar cross section slidable in said holder; manually operable, one-way feeding means slidable on saidholder and successively engageable with portions of said strip within said holder 'for feeding successive portions of said strip from said holder; and flexible means on said holder engageable by said feeding means and adapted to be flexed therebyinto engagement with said strip for preventing reverse movement of said strip.

2. An erasing device, including: a tubular holder of substantially rectangular cross section; an eraser strip of similar cross section slidable in said holder; manually operable, one-Way feeding means reciprocable on said holder and engageable with different portions of said strip during successive reciprocations of said feeding means so as to feed an end of said strip predetermined increments of movement in one direction from an end of said holder; and resilient means on said holder engageable by said feeding means and adapted to be exed thereby into engagement with said strip so as to prevent reverse movement of said strip.

3. A device as defined in claim 2 in which said feeding means consists of a slider slidable on said ais/41,4151

holder vand having resilient pawls engageable with opposite sides of said strip to feed the same in'one direction when said :slider is slid in said one direction, said pawls being adapted to slide along said strip in the opposite direction when said strip is .held vagainst .movement in said opposite direction by said resilient means, said -pawls overlying said resilient means upon reaching the limit of movement of said slider in said opposite direction.

4. A device as dened in claim 3 in which said holder has openings through which said paWls eX- tend to .engage said strip.

5. An erasing device, comprising: a tubular holder of substantially rectangular' cross section, said holder having openings in its wider sides and resilient tongues projecting inwardly from ysaid sides; an eraser strip of similar cross section slidable in said holder; and a slider reciprocable longitudinally on said holder and having resilient pawls extending through said openings 'and engageable with said strip to feed the same predetermined increments during successive movements of said slider in one direction so as to project said strip from an end of said holder, said pawls being adapted Vto slide 'relative to .said strip when said slider is moved in the opposite direction, said tongues adapted to engage said .strip to prevent reverse movement thereof `during movement of said slider in said opposite direction, said pawls overlying and depressing said .tongues into firm, unyielding engagement with said strip when said slider reaches the limit of its movement in said opposite direction .so as to cause said tongues to effectively retain said strip in its projected position when the erasing device is applied to use.

6. An erasing device, comprising: a tubular holder of substantially rectangular cross section, said holder having openings in .its wider sides and resilient tongues projecting inwardly from said sides; an eraser strip of similar cross Section slidable in said holder; and a tubular slider surrounding said holder and reciprocable longitudinally on said holder and having resilient pawls extending through said openings and engageable with said strip to feed the same predetermined increments during successive movements of said slider in one direction so as to project said strip from an end of said holder, said pawls being adapted to slide relative to said strip when said slider is moved in the opposite direction, said tongues being adapted to engage said strip to prevent reverse movement thereof during movement of said slider in said opposite direction, said pawls overlying and depressing said tongues into firm, unyielding yengagement with said strip when said slider reaches the limit of its movement in said opposite direction so as to cause said tongues to eectively retain said strip in its projected position when the erasing device is applied to use.

Iii.

l?. erasing device, comprising: fa tubular beider fof substantially rectangular cross section, said holder having openings in its Wider sides i:rnd resilient tongues -p'r'oiectin'g inwardly from said sides; fan eraser strip of similar cross section slidable in said holder; a tubular slider surrounding said .holder 1land reciprocable .longitudinally on 'said holder and having resilient pawls 4extending through said Aopenings .and engageable with said .strip to feed Athe same predetermined increments dur-ing successive movements of said slider .in one direction so afs to project said strip 4from an end of said holder, said pawls being .adapted to slide .relative to Ysaid strip when said slider is moved in the :opposite direction, 'said tongues being :adapted :to engage said strip to prevent .reverse movement thereof during movement of said slider 2in said opposite direction; Vand. stop means on said holder engageable withsaid slider for limiting lthe extent of reciprocatory movement :of said slider, said pawls overlying and depressing said tongues into firm, unyieldin'g `engagement with said strip :when saidsliderre'achesthe limit of its movement in said opposite direction so as to cause .said tongues to effectively retain said strip in its projected position when .the erasing device is applied .to use.

8. A .device .as deiined in claim 5 in which said holder is provided with resilient jaws at its vend from which said vIstr-ip Vis projected, said .jaws ,being 4adapted .to engage opposite sides of said )strip when .iieXed toward each other, said slider being engageable with said jaws to `ilex the same.

9. A device .as denedin claim .5 in which 'said holder isprovided with resilient jaws at its end from which said strip is projected, and said slider is provided with inturned lips engageable with and adapted to depress .said jaws into firm engagement with said strip when said slider is moved in saidopposite direction.

l0. A device vas defined in claim 5 in which said tongues project in said one direction within said openings in alignment with said pawls so that movement of said slider in said opposite direction causes said pawls to ride up on said tongues to force said tongues .into nrm engagement with 'said strip.

BRUCE BURNS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 173,065 Safford Feb. 1, 1376 267,643 Boman Nov. 14, 1882 '799,618 St. John Sept. l2, 1996 1,451,933 Weig Apr. 1'7, 1923 1,926,289 Kovacs Sept. 12, 1933

Images