US3026847A

US3026847A - Rotary electric pencil and rack

Info

Publication number: US3026847A
Application number: US808798A
Authority: US
Inventors: Jr John A Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-04-24
Filing date: 1959-04-24
Publication date: 1962-03-27
Anticipated expiration: 1979-03-27

Description

March 27, 1962 J. A. ANDERSON, JR

ROTARY ELECTRIC PENCIL AND RACK Filed April 24, 1959 2 Sheets-Sheet l Anwen/EVS March 27, 1962 Filed April 24, 1959 J. A. ANDERSON, JR

ROTARY ELECTRIC PENCIL AND RACK 2 Sheets-.Sheet 2 ite ttes ice 3,026,847 RGTARY ELECTRIC PENCIL AND RACK John A. Anderson, Jr., Tampa, Fla. (7 Lexington Drive, Crotou on Hudson, N.Y.) Filed Apr. 24, 1959, Ser. No. 808,798 3 Claims. (Cl. 1Z0-9) This invention relates to a rotary electric pencil and a rack upon which the pencil is to be suspended while not in use and which serves also to deenergize the pencil.

The primary object of the invention is to provide an efficient, practical, and work-saving pencil of the character indicated which is especially suitable lfor draftsmen and which draws upon a drawing surface with a minimum of manual pressure and enables the drawing of heavy or broad lines without exertion of heavy pressure, with the economical use ofthin pencil leads which require no sharpening. l Y

Another' object of the invention is to provide a pencil of the character indicated above which is of simple and sturdy construction, is composed of a small number of simple and easily assembled and disassembled parts, and which can be made in well-finished and long-lived forms at relatively low cost.

A `further object of the invention is to provide a hanging rack for the said pencil, which is designed to be secured to any convenient support above a drawing board or table, and upon which the pencil is adapted to be suspended in an erect position, with either end up, and which cooperates with the pencil to disconnect the pencil from its current source while the pencil is suspended in erect position on the rack.

A still further object of the invention is to provide a pencil of the character indicated above which contains a gravity-operated switch, such as a mercury switch, which closes the electrical circuit to the pencil only in a tilted drawing position of the pencil, and opens the circuit and renders the pencil inoperative when the pencil is in an erect position.

Still another object of the invention is to provide, in a pencil of the character indicated above, simple and efficient mechanical pencil-lead holding and feeding or advancing means.

ther important objects and advantageous `features of the invention will be apparent from the following description and the accompanying drawings, wherein, for purposes of illustration only, a specific form of the invention is set forth in detail.

In the drawings:

FIGURE 1 is a side elevation of a pencil of the invention;

FIGURE 2 is a central longitudinal section taken on the line 2-2 of FIGURE l, and partly broken away;

FIGURE 3 is a perspective view of a pencil suspended by magnet means from a rack of the invention;

FIGURE 4 is a `schematic lwiring diagram of the motor and rack switch circuit of FIGURE 3;

FIGURE 5 is a perspective view of another form of pencil and rack of the invention wherein the pencil contains a gravity operated switch;

FIGURE 6 is a schematic wiring diagram showing the motor and switch circuit of FIGURE 5;

FIGURE 7 is a perspective view of a still further form of pencil and rack of the invention, wherein the pencil is suspended from the rack on a switch operating hook; and

FIGURE 8 is a schematic wiring diagram of the motor and switch circuit of FIGURE 7.

Referring in detail to the drawings, wherein like or related numerals designate like parts throughout the several views, and rst to FIGURES 1 and 2 thereof, the illustrated electric pencil, generally designated 10, comprises a longitudinally or vertically elongated, preferably cylindrical, case 12, having a cylindrical axial bore 14, defining a side wall 16. The rear or upper end of the side wall 16 is reduced and tapered, as indicated at 18, and terminates in a hollow cylindrical head 20, having relatively large and diametrically opposed openings 22 in its side wall. At the upper or 4rear end of the case 12 is an upper or rear end wall 24 provided with an axial opening 26, smaller in diameter than the case bore 14 and grooved, as indicated at 28, in its edge to accommodate anti-friction means, such as ball bearings 30.

On the forward or lower end of the case 12 is a tapered reduction 32 which merges into an axial tubular nger grip 34, having a suitably knurled outer surface 36, and having a reduced axial bore 38 which can be of substantially the sarne diameter as the opening 26 in the upper case end wall 24. At longitudinally spaced points the `bore 38 is grooved, as indicated at 40, to accommodate anti-friction `bearing means, such as ball bearings 42. The lower or forward -part o' the bore 38 is axially flared, as indicated at `44.

Turning in and held against endwise movements by the

bearings

30 and 42 is a tubular cylindrical outer or armature shaft 46, which has, at its upper or rear end 48, a groove Si) receiving the bearings 30, and adjacent to its forward or lower end 52, grooves 54 receiving the bearings 42. The outer or armature shaft146 is a substantially close fit in the opening 26 of the upper end wall 24 of the case 12 and on the bore 38, and has at its lower -or Iforward end a flared portion 56, conforming to the llare 44 of the bore 38. The lower or forward end 52 of the outer shaft 46 extends slightly beyond the lower or forward end 35 of the finger-piece 34, as shown in FIG- URE 2.

The armature shaft 46 has an axial threaded bore 58, of uniform diameter, which extends downwardly from a point 60 near its upper or rear end '48 to a point 62 near its lower or forward end 52, and defines at these points an internal bearing shoulder 64 at the upper or rear end of the outer shaft l46, and an internal stop shoulder 66 at :the lower or forward end of the shaft 46. Extending rotatably through the axial opening 26 in the bearing `shoulder 64 is a threaded pin 70 on which is threadably engaged a knurled head 72 which is rotatably confined in the head 20 and is reachable through the openings 22 therein. The threads of the -pin 70 are righthand screw threads.

Suitably -lixed on the exterior of the armature shaft -46 and extending therealong are lsuitable diametrically opposed armature bars 74, and suitably secured to the inner surface of the case side wall `16 and coextensive with the armature bars 74, are xed coils 76, which are suitably connected to

wires

78 and 80 which lead out of the case 12 through a grommet 82 secured in one of several circumferentially spaced Ventilating airholes 84 provided in the rear or upper tapered portion 18 of the case. Similar airholes 86 are provided in the lower tapered portion 32 of the case 12. It will be understood that any suitable form of electric motor confined in the case 12 is contemplated by the present invention, for rotating the armature shaft 46.

The bore 58 of the armature shaft 46 is provided for substantially its entire length with a continuous righthand screw thread 88. An enlarged ibore portion or socket 96 at the forward end of the bore 58, beyond the stop shoulder 66 is provided with left-hand screw :threads 92.

The pin 7i) carrying the knurled head 72 is on the upper or rear end of an inner shaft 94 which comprises a short smooth cylindrical boss 96 on its upper or rear end which bears endwise against the bearing shoulder 64 at the upper or rear end of the outer shaft bore 53 and turns in a smooth bore portion 95 adjacent to the shoulder 64. Ex-

tending downwardly or forwardly from the boss 96 are two longitudinally elongated straight and laterally spaced and diametrically opposed rods 98, which have lower or forward ends 100 which terminate at the outer end 52 of the armature shaft 46, and which are fixed together in spaced relation to each other by a cylindrical block 161.

Sliding along and non-rotatable upon the inner shaft rods 98 is a lead pusher plug or follower 102 which has a smooth lower portion 104 and an externally threaded upper portion 106, which is threadably engaged with the thread 88 in the bore 58 of the armature shaft 46. Formed in the lower end of the plug 102 is an axial socket 108 which is sized to snugly receive the upper end of a relatively thin pencil lead 110. At the forward or lower ends of the rods 98 the block 101 has a smooth bore 112 therethrough through which the lead 110 passes and which acts to center the lead 110 in the inner shaft 94, while at the same time offering some frictional resistance to passage of the lead therethrough.

A conical combined inner shaft bearing and lead gripping tip 114 has its larger rear or upper end 116 abutting the lower or forward end 52 of the armature shaft 46 and has thereon a reduced hollow boss 118 which is externally threaded into the socket in the lower end of the armature shaft 46. The tip 114 is hollow and has internal lands 122 which form a restricted axial passage 124 for the lead 110 through the tip 114 and serves to hold the lead 110 in axial position and to frictionally resist both endwise and rotational movements of the lead 110 relative to the tip 114.

It will be apparent from the foregoing that when the device is energized by connection to a suitable source of current (not shown) the armature shaft 46 is rotated, preferably in a clockwise direction, whereby the point 12S of the lead 110, extending beyond the tip 114, is rotated. As the rotating point 125 is applied to a drawing surface and moved thereover, a desired line is drawn. Because of the abrasion of the rotating point 125 by the contact with the drawing surface, both fine and heavy lines can be drawn thereon with a minimum of downward pressure upon the pencil 10.

For extending the lead 110 downwardly through the inner shaft 94 and the tip 114 as lead is consumed in drafting operations, the knurled knob 72 is rotated so that the plug or follower 102 is moved forwardly in the threaded bore 58 of the armature shaft 46 and pushes the lead 110 forwardly the desired amount. This lead feeding operation can also be performed with the motor M of the pencil running, simply by grasping the knob 72 and holding the same stationary, until the desired length of lead has been projected. Positive indication of exhaustion of the lead 110 is provided by stoppage of the motor, which occurs when the plug or follower 102 has been fed to its forward limit and abuts the upper end of the boss 118 of the tip 114. When this occurs, a small length of lead 110 remains in the tip 114 and this can be removed by pulling it out by the point 125. Then, by holding the tip 114 stationary with one hand, to prevent operation of the motor while turning the knob 72 with the other hand in a direction to move the plug or follower 102 upwardly on the inner shaft 94 to its starting position, a new lead 110 can be inserted through the tip 114 and through the inner shaft 94 into the socket 103 in the follower 102 or this can be done with the motor deenergized.

In order to remove the inner shaft 94 for removing broken lead or for cleaning purposes, the knurled knob 72 and the tip 114 are rotated in opposite directions, being oppositely threaded, whereupon the inner shaft 94 can be pulled out until it strikes the follower 102, whereat the follower 102 and the inner shaft 94 can then be together rotated out of the armature shaft 46.

The upper or rear end 119 of the head 20 or the entire head is of magnetizable material which is designed for magnetic suspension from a hanger rack, generally designated 120, in FIGURES 3 and 4.

The rack 120 comprises a suitable preferably rectangular fiat housing 122 having a bottom wall 124 having inset therein a longitudinal magnet bar 126 with which the upper end of the head 20 is engageable, as shown in FIG- URE 3, to releasably suspend the pencil 10 from the rack 12.0. The magnet bar 126 is, as shown in FIGURE 4, connected at one end by a wire 128 which is connected to a Wire 73 leading from one side of the pencil motor M and at the other end by a wire 130 to the other wire 80 leading from the other side of the motor, the wires 78 and being enclosed in a spring core or conduit 132 which has thereon a male connector plug 134 adapted to be removably plugged into a receptacle (not shown) in the bottom wall 124. The rack housing 122 contains a step-down, low-voltage transformer T, to which the wires 7S and 80 are connected, and which has a cord 138 leading out of the housing 122 having a connector plug 140 thereon, for plugging into an available current outlet (not shown). Because 'of the electrical connections described above, engagement of the pencil head 20 with the magnet bar 126 shunts the motor circuit and deenergizes the pencil motor M, while the pencil 10 is suspended from the rack 125B. The motor M is energized for use of the pencil 10 when withdrawn from the rack 120.

In the modified arrangement shown in FIGURES 5 and 6, the rack a is devoid of a magnet bar but has a pencil supporting bracket 126a having arms 144 between which the knurled fingerpiece is adapted to be frictionally engaged for suspending the pencil 10a on the rack 120a. In this arrangement, there is provided within or on the pencil case 12a a gravity operated switch, such as a mercury switch 150, which is shunt-connected in the wire 80 leading to one side of the motor M, as shown in FIGURE 6. As a result, the pencil motor M is energized only when the pencil 10a is in a tilted drawing position, and is deenergized when in an erect perpendicular position, as shown in FIGURE 5 In the further modified arrangement shown in FIG- URES 7 and 8, the housing 122b is devoid of a magnet bar and of a bracket, and has instead a hook 126b which is a vertically swingable actuator for a suitable switch S, located within the housing 122b and which is connected in a wire S0 leading from one side of the motor M. The head 2017 of the pencil 10b has thereon an upstanding loop or eye 152 adapted to be engaged over the hook 126b so as to depress the actuator and open the switch and deenergize the pencil motor only while the pencil 10b is suspended in the hook.

Although there has been shown and described herein preferred forms of the invention, it is to be understood that the invention is not necessarily confined thereto, and that any change or changes in the structure of and in the relative arrangements of components thereof are contemplated as being within the scope of the invention as defined by the claims appended hereto.

What is claimed is:

l. An electric pencil comprising a tubular case having a sidewall and forward and rear ends` a tubular armature, the armature shaft journalled at its ends in related ends of the case, motor means within the case for rotating the armature shaft relative to the case, a pencil lead holder, threaded in the armature shaft, a pencil lead having a rear end securably engaged in the holder and a forward end, 'a pencil lead centering element fixed in the forward end of the armature shaft, said centering element having a bore through which the lead extends, and manual means for rotating the lead holder relative to the armature shaft for feeding and retracting the lcad.

2. An electric pencil comprising a tubular case having a sidewall and forward and rear ends, a tubular armature, the armature shaft journalled at its ends in related ends of the case, motor means within the case for rotating the armature shaft relative to the case, a pencil lead holder threaded in the armature shaft, a pencil lead having a rear end seeurably engaged in the holder and a forward end, a pencil lead centering element fixed in the forward end of the armature shaft, said centering element having a bore through which the lead extends, and manual means for rotating the lead holder relative to the armature shaft for feeding and retracting the lead, and a combined shaft bearing and lead gripping tip xed on the forward end of the armature shaft, said tip having a restricted axial passage therethrough through which the forward end of the pencil lead extends, said passage being in frictional engagement with the lead for limiting rotation and endwise movement of the lead relative to the tip.

3. A11 electric pencil comprising a tubular case having a sidewall and forward and rear ends, a tubular armature, the armature shaft journalled at its ends in related ends of the case, motor 4means Within the case for rotating the armature shaft relative to the case, a pencil lead holder, threaded in the 'armature shaft, a pencil lead having a rear end securably engaged in the holder and a forward end, a pencil lead centering element Xed in the forward end of the armature shaft, said centering element having a bore through which the lead extends, and manual means for rotating the lead holder relative to the armature shaft for feeding and retracting the lead, the bore of the armature shaft being threaded, and said lead holder comprising a smooth inner shaft disposed Within the armature shaft bore and smaller in diameter than the armature shaft bore, means at related ends of the inner shaft engaging elements on related ends of the armature shaft and precluding endwise movement of the inner shaft relative to the armature shaft, a pin fixed on the rear end of the inner shaft and extending rearwardly beyond the rear end of the armature shaft, a rotary knob fixed on said pin for rotating the inner shaft relative to the armature shaft, a follower threaded in the bore of the Iarmature shaft and circumposed non-rotatably on the inner shaft, said follower having a socket in its forward end in which lthe rear end of the pencil lead is engaged.

References Cited in the ile of this patent UNTED STATES PATENTS 1,357,980 Hawkins Nov. 9, 1920 2,151,274 Hindman Mar. 21, 1939 2,572,682 Urish Oct. 23, 1951 2,591,119 Biggs Apr. 1, 1952 2,701,417 Graham Feb. 8, 1955 2,807,236 Wolf Sept. 24, 1957 FOREIGN PATENTS 370 Great Britain Oct. 13, 1852