US3092081A

US3092081A - Sharpener

Info

Publication number: US3092081A
Application number: US171515A
Authority: US
Inventors: George R Fraser
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-02-06
Filing date: 1962-02-06
Publication date: 1963-06-04
Anticipated expiration: 1980-06-04

Description

June 4, 1963 G. R. FRASER 3,092,081

SHARPENER Filed Feb. e', 1962 United States Patent tlice theater' Patented .tune 4, 1956s 3,092,031 SHARPENER George R. Fraser, Portsmouth, N.H. Filed Feb. 6, 1962, Ser. N0. 171,515 11 Claims. (Cl. 1Z0-95) The invention relates to a Sharpener for any type of article, however, its principal application is lfor sharpening the lead of pencils and particularly the lead of a pencil of the type having an insertable lead. The sharpener may be used to give a lead either a conical point or a dat point. Also merely by projecting the lead a greater or lesser distance into the Sharpener a longer or a blunter point is secured. The Sharpener is designed t be of small size so that it can be carried in the pocket.

It is an object of the invention to construct a sharpener having an abrasive means driven by an electric motor and the drive connection between the motor and the abrasive means is a flexible drive shaft having at least lateral exibility.

Another `object is as above with the addition that a supporting means is provided for the article to -be sharpened which means is rotatably mounted and a drive connection is provided between the motor and the rotatable supporting means.

A still further object is to provide a sharpener having an abrasive means driven by a motor and the driving connection between the motor and the abrasive element is laterally flexible for four results, namely, the axis of the motor can be at a substantial angle with respect to the axis of the supporting means for the article and spaced away from the article supporting means but with the periphery of the abrasive element at a relatively small angle with respect to the axis of the supporting means, secondly the abrasive element is flexed or pressed inwardly against the article or lead, thirdly the abrasive element is free for radial movement relatively to the supporting means so that variations in sharpness of point can be secured merely by inserting the article the desired extent in contact with the abrasive means, and fourthly an inexpensive drive connection is provided between the driving motor and the rotatable article support.

Another object is to construct a Sharpener having the above advantages and results and utilizing a very simple structure which is economical to manufacture.

A still further object is to construct a Sharpener which is of small size and light in Weight so that it may be carried in a pocket.

Another object is to construct a Sharpener mounted in a casing with a exible wall and having a switch located adjacent thereto such that depression of the exible wall closes the switch to operate the Sharpener.

A further object is to provide a Sharpener such that the abrasive means uses an abrasive sleeve ywhich may be easily removed and replaced.

Other objects of the invention will be more apparent from the following description when taken in connection with the accompanying drawings illustrating a preferred embodiment thereof in which:

FIG. 1 is a section through the casing of a full sized Sharpener taken on line- 1-1 of FIG. 2;

FIG. 2 is a sectional View taken on line 2-2 of FIG. l;

FIG. 3 is a sectional view taken on line 3 3 of FIG. 1;

FIG. 4 is a cross section taken on line 4-4 of FIG. 1;

FIG. 5 is a partial section showing the motor mount- FIG. 6 is an enlarged View of the abrasive element imparting a relatively blunter point to a pencil lead; and

FIG. 7 is an enlarged partial section of the abrasive element :and with a longer lead or a lead projecting farther outwardly from the lead holder or pencil.

The Sharpener includes a frame or base 10 which is preferably an electrical insulating material such as plastic on which is mounted a small electric motor 11 of any suitable type. The motor is shown attached to the frame by brackets 12 at each end thereof and a screw 13 for each bracket. For a portable Sharpener the motor is such that it can be energized from two or three small dry cells. 'I'here is less drain on the dry cells and hence they last longer if the motor has a gear reduction to a drive shaft, however, such constructions are more costly and for an inexpensive Sharpener a simple motor may be used in which the motor shaft is the drive shaft. The motor :or `drive shaft 14 projects from the motor.

A supporting means 17 for the article is mounted on the frame. The supporting means particularly shown is tubular and the article or pencil is projecte-d into the tube until it engages a stop 18 at the end thereof. The stop conveniently is a reduction in the diameter of the bore through the tube. The stop has a holte 19 therethrough which for a lead Sharpener is a little larger than the lead L of a pencil P. Best results are secured if the pencil is rotated iby the motor, hence the supporting means is mounted for rotation so that the article or pencil is rotated therewith solely by resting on the stop to give a conical point to the pencil lead. The frame, therefore, carries suitable bearing means. 'l'he frame includes a llange Ztl which liange and frame may carry a lower bearing 21 for the lower end of the supporting means. It is desirable to have this bearing spaced farther than as illustrated from the abrasive means and the dust generated theneby. The bearing means also includes an upper bearing 22 which is secured tfo the frame by a screw 23. The supporting means carries a pair of spaced collars 24 and 2S and engaging the ends of the bearing 22 to retain the rotatable supporting means in axial position. A satisfactory collar 25 has been a rubber band.

A suitable drive connection is preferably provided between the ,drive shaft and the supporting means, that shown including a pinion 28 secured to the drive or motor shaft and a gear 29 meshing therewith and suitably secured to the supporting means 17 such as by a press lit.

The abrasive means 31 is shown fas cylindrical although it may be conical and the abrasive portion may be of any desired construction. A simple form of abrasive means includes a body 32 shown as cylindrical having a shoulder 33 at the upper end theneof. A screw 34 with an enlarged head is threaded into the other end of the body and a cylindrical abrasive sleeve 35 secure-d on the body between the shoulder 33 and the head of the screw 34. The head of the scnew also serves as a stop for the end of the lead when the longest point is desired. Preferably the body car-ries a limit nub 36 at the upper end thereof as will appear more `fully hereinafter and a stub shaft 37.

A flexible drive means is provided between the end of the drive shaft 14 and the abrasive means and particularly the stub shaft 37 thereof. The flexible drive means is the sole mounting for the abrasive means. Lateral flexibility is all that iis needed, however, a simple and inexpensive driving connection is a helical spring 40'. A spring 1/s inch in diameter and about .010 of an inch diameter wire has been used successfully. It is desirable that the spring be not too stiff. A helical spring is particularly advantageous for this flexible drive means for several reasons,

the first of which is that by using a spring having an internal diameter a little less than the diameter of the

shafts

14 and 37, the ends of the spring are merely pressed onto the ends of the two shafts and an effective driving connecandassi e tion is established thereby without more. A second advantage is that a spring and its simple attachment to the shaft ends constitutes an inexpensive element with inexpensive assembly. Thirdly with the motor shaft used as the drive shaft, it enables a direct connection between the motor shaft and the abrasive means with the motor shaft axis being at a substantial angle with respect to the supporting means axis 26. Fourthly and particularly it provides a simple construction for securing varying angles between the axis of the abrasive means and the axis of the supporting means or a lead L which is projected therefrom for securing different sharpness of points. The spring has an unsupported portion between the ends of the two shafts of about a quarter of an inch giving lateral ilexibility for the abrasive means. The spring coils `between the ends of the two shafts may be spread to reduce the lateral tension induced by the spring taking an arcuate form. The direction of the helix of the spring should be such with respect to the drive shaft rotation that the spring tightens on the shafts. A more positive anchorage such as solder may be used if desired but the press tit is adequate. The screw 3ft also is tightened rather than loosened by the direction of rotation of the abrasive means.

The flexible drive means enables the motor when the connection is made directly with the motor shaft to be mounted sufficiently spaced from the supporting means to provide room therefor and yet the periphery of the abrasive means is a-t a relatively small angle with respect to the axis 26 of the supporting means. It has been found than an angle of about 9 degrees between the periphery of the abrasive means and the axis 2e is suitable for an initial or rest position for a blunter point and when the abrasive means is moved laterally outwardly by the lead L for a long point the angle is about 5 degrees. The dexibility of the flexible drive means or connection presses the abrasive means toward the axis of the supporting means and hence against the lead L of a pencil to be sharpened and also enables the abrasive means to move laterally away from the axis solely by insertion of the lead in order to secure a longer or sharper point, as shown in PEG. 7.

The rest position of the periphery of the abrasive means, and for its axis if a cylindrical unit is used, is about 9 degrees with respect to the axis of the supporting means. The drive shaft should have a minimum angle with respect to -the axis of the supporting means of about degrees in order to provide an arc for the unsupported or liexible portion of the tlexible drive means 4th With the drive shaft being the motor shaft, the bulk of the motor prevents use of this minimum angle. As mentioned, hereinbefore, one of the functions of the exible drive means is to enable the motor 11 to be spaced laterally from the supporting means. The axis 15 of the motor shaft may be angularly disposed with respect Ito the axis 26 of the supporting means in a region of roughly 30 to 45 degrees. The lesser angle is determined largely by the motor size and the larger angle is not limiting so far as operability is concerned but a greater angle is wasteful of the low power output of the small motor used. The angle used in a Sharpener which has been constructed and operates satisfactorily is about 35 degrees. The motor axis 15 and supporting means axis 26 intersect or approximately intersect and the point of intersection for this form is approximately at the hole 19. With a lesser angle between a drive shaft and the axis of the supporting means the point of intersection would be lower.

The nub 36 engages the end of the supporting means to provide limit means to limit the movement radial inward movement of the abrasive means so that its periphery at the upper end is at the hole 19. The nub retains the abrasive means against lateral displacement by engaging guide means shown as a slot 4l (FIG. 4) provided in the flange 26B of the frame. Actually one edge only of the slot is needed since the direction of rotation of the shaft and abrasive means moves the same against one surface.

In the construction particularly illustrated the motor is driven by dry cells C, two being particularly shown. The frame 1t? carries suitable mounting and electrical connecting means for the dry cells, that particularly shown being a central clip 43', which is secured to the frame such as by a rivet 44. 'This clip is located about centrally of the length of the dry cells. A connecting bracket d5' is also secured to the frame it) such as by a rivet 46, the function of which connecting bracket is to engage the lower ends of the cells and establish an electrical connection therebetween. A second bracket 47 is also secured to the frame by a rivet 51 (FIG. 4) and it engages the other end of one of the dry cells to hold the cell longitudinally. This bracket is electrically connected such as by a wire 43 with a contact on the motor. A third bracket is secured to the base 19 such as by a rivet which bracket engages the upper end of the other dry cell to hold it in place longitudinally and establish an electrical connection with this cell. This third connecting bracket is extended and bent over to form a switch element 5t) and is normally spaced from the casing of the motor so that an electrical connection may be established with the motor casing by Contact. The circuitry is completed by a ground connection 5l between the windings of the motor and the casing of the motor. For a three cell construction another form of electrical connection between cells would be used as known to the art. Any suitable switch construction may be used.

The frame with the parts of the Sharpener mounted thereon are received Within a casing or housing 53, one end of which is open and receives a cover 54 which may be merely pressed into the opening. The housing has a ilexible wall 55 at the switch element 5? which engages the switch element 5t). Upon depression of the flexible wall 55 the switch element 50 is pressed into contact with the casing of the motor to complete the circuit through the motor. Other constructions may be used for closing the switch.

It is desirable that a dust chamber 53 be provided surrounding the abrasive means. This is shown rectilinear cult out in the lower corner of the casing in which is received the dust chamber and completes the overall rectilinear shape of the housing. Retaining and dust sealing ilanges 59 are provided projecting from a horizontal wall 69 at the cut out and forming a part of the casing or housing. A hole is provided in the wall 69 through which the abrasive means projects. The shape of the dust chamber ills in the rectilinear shape of the casing so that an overall rectangular form of housing results. In order to empty the same the dust chamber is pulled downwardly to separate the same from the housing. This also exposes the abrasive means for replacement of the abrasive sleeve 35. A gasket 61 may be provided between the frame flange Ztl and the wall 60.

The rotation of the supporting means i7 rotates the pencil P, merely by resting therein, and its lead L to provide a conical point. The abrasive sleeve 35 and the side of the lead L engaging the sleeve rotate in opposite directions but the contacting surfaces move in the same direction but at a differential speed because of the gear reduction between the gears 2S and 29 and by slippage of the pencil within the supporting means. Y Since the pencil merely rests in the supporting means, by holding the pencil stationary a flat point will be secured and the length of the ilat point is selected by the extent of projection of the lead. With the end of the lead contacting the head of the screw, the maximum length is secured.

This invention is presented to lill a need for improvements in a Sharpener. It is understood that various modifications in structure, as well as changes in mode of operation, assembly, and manner of use, may and often do occur -to those skilled in the art, especially after beneiittiug from the teachings of an invention. This disclosure illustrates the preferred means of embodying the invention in useful form.

What is claimed is:

1. A Sharpener for the end of an article comprising a frame, a supporting means for the article having a longitudinal axis, an article stop at the end of the supporting means having a hole, a motor mounted on the frame, a drive shaft driven by the motor having an axis, the two axes extending at an angle to each other in the region of about to 45 degrees, the drive shaft having an end, a flexible driving means attached to the drive shaft and extending beyond the end thereof providing a free end and a laterally exible portion between the free end and the drive shaft, an abrasive means including a body having an abrasive periphery, means mounting said body on the resilient drive means with the upper end of said body adjacent to the stop of the supporting means, limit means carn ried by the abrasive means and engaging `the frame with the upper end of the abrasive periphery approximately in line with the hole of the supporting means and with the periphery of the abrasive means at an angle of about 9 degrees with respect to the axis of the supporting means when the limit means is engaged whereby the flexible portion of the resilient drive means is bent in an arc to resiliently press said abrasive means towards the supporting means axis.

2. A Sharpener as in claim 1 in which the flexible drive shaft is a helical spring.

3. A Sharpener as in claim 1 in which the limit means includes a nnb at the upper end of the abrasive means, and guide means carried by the frame and extending generally radially from the supporting means and engaged by the nub to retain the abrasive means against lateral displacement.

4. A Sharpener as in claim 1 including a casing receiving the frame and parts mounted thereon, the casing having a depressible Wall, and a normally open switch element carried by the frame and engaged by the depressible Wall of the casing to close the switch and energize the motor.

5. A Sharpener as in claim l including a casing receiving the frame and parts mounted thereon, the casing being generally rectilinear With a rectilinear cut out at one corner, a dust chamber having an open top through which the abrasive means projects and dimensioned to fit the rectilinear cut out, and means releasably retaining the dust chamber on the casing.

6. A Sharpener as in claim 1 in which the motor is mounted at an angle adjacent to the supporting means, the motor has a motor shaft and the drive shaft is the motor shaft with the flexible driving means connected directly therewith.

7. A Sharpener as in claim 1 including bearing means carried by the frame rotatably mounting the supporting means, and a driving connection between the drive shaft and the supporting means to rotate the latter.

8. A Sharpener as in claim 7 in which the flexible driving means is a helical spring.

9. A Sharpener as in claim 7 including guide means carried by the frame and extending generally radially from the supporting means and engaging the abrasive means to retain the latter against lateral displacement.

10. A Sharpener as in claim 7 including a casing of generally rectilinear form having a rectilinear cut-out at a lower corner and a horizontal Wall, the horizontal Wall having a hole therein through which the abrasive means projects, a dust chamber, and means carried by the horizontal wall at the opening to removably receive the dust chamber.

11. A Sharpener as in claim 7 in which the motor is located adjacent to and at the side of the supporting means and positioned with its axis at an angle to the axis of the supporting means in the region of 30` to 45 degrees, and the motor having a motor shaft which is the drive shaft.

References Cited in the le of this patent UNITED STATES PATENTS 777,202 Hambruch Dec. 13, 4 1,079,312 Chadwick Nov. 18, 1913 2,613,645 Von Kameniczky Oct. 14, 1952 2,914,030 Behrens Nov. 24, 1959

Claims

1. A SHARPENER FOR THE END OF AN ARTICLE COMPRISING A FRAME, A SUPPORTING MEANS FOR THE ARTICLE HAVING A LONGITUDINAL AXIS, AN ARTICLE STOP AT THE END OF THE SUPPORTING MEANS HAVING A HOLE, A MOTOR MOUNTED ON THE FRAME, A DRIVE SHAFT DRIVEN BY THE MOTOR HAVING AN AXIS, THE TWO AXES EXTENDING AT AN ANGLE TO EACH OTHER IN THE REGION OF ABOUT 15 TO 45 DEGREES, THE DRIVE SHAFT HAVING AN END, A FLEXIBLE DRIVING MEANS ATTACHED TO THE DRIVE SHAFT AND EXTENDING BEYOND THE END THEREOF PROVIDING A FREE END AND A LATERALLY FLEXIBLE PORTION BETWEEN THE FREE END AND THE DRIVE SHAFT, AN ABRASIVE MEANS INCLUDING A BODY HAVING AN ABRASIVE PERIPHERY, MEANS MOUNTING SAID BODY ON THE RESILIENT DRIVE MEANS WITH THE UPPER END OF SAID BODY ADJACENT TO THE STOP OF THE SUPPORTING MEANS, LIMIT MEANS CARRIED BY THE ABRASIVE MEANS AND ENGAGING THE FRAME WITH THE UPPER END OF THE ABRASIVE PERIPHERY APPROXIMATELY IN LINE WITH THE HOLE OF THE SUPPORTING MEANS AND WITH THE PERIPHERY OF THE ABRASIVE MEANS AT AN ANGLE OF ABOUT 9 DEGREES WITH RESPECT TO THE AXIS OF THE SUPPORTING MEANS WHEN THE LIMIT MEANS IS ENGAGED WHEREBY THE FLEXIBLE PORTION OF THE RESILIENT DRIVE MEANS IS BENT IN AN ARC TO RESILIENTLY PRESS SAID ABRASIVE MEANS TOWARDS THE SUPPORTING MEANS AXIS.