The present invention relates generally to the field of writing instruments, and in particular, to a new and useful pencil mechanism in the form of a pencil cartridge that can be used to replace pen cartridges in pens that where not originally designed to accept anything other than the pen cartridge configured for that pen.
The Classic Century® ball point pen manufactured and sold by A. T. Cross Company or Lincoln, R.I., is a slim, stylish pen with a twist mechanism for extending and retracting the writing tip of its ballpoint pen refill cartridge that is specially configured for use in the pen. Although a mechanical pencil version of the Classic Century® writing instrument line is also available, the internal workings of the pencil are very different from these of the pen and they cannot share refill cartridges. Details about the internal mechanism of the Classic Century® pen are disclosed in U.S. Pat. No. 5,518,330 to Gervais et al., which is incorporated here by reference.
A mechanical pencil cartridge must have additional and different functionality over the functions required by a pen cartridge. For example, a pen cartridge must be extendable and retractable as a whole to expose the writing tip, since there is no relative movement between the writing tip and the rest of the cartridge. By contrast, a mechanical pencil cartridge must be capable of projecting the end of its length of writing lead beyond the end of the cartridge itself, and also beyond the end of the writing instrument barrel, to permit writing and to protect the tip. In addition, there must be some way of holding the lead fixed in the cartridge for writing, to avoid simply pushing the writing tip back into the cartridge upon pressing the tip to paper. This fixing mechanism must be releaseable, however, to allow the writing tip of the lead to be pushed back into the cartridge when not in use so the instrument and be stored, e.g. in a pocket. Further, the mechanism must be able to cycle new lead out from the tip as the lead is used up and again to allow for alternate fixing of the lead for writing, and releasing of the lead for its retraction into the cartridge for storage.
It would be a feat to create a mechanical pencil cartridge that can be used in a pen mechanism that was not originally design for it, while extracting all of the different and additional functions needed for a mechanical pencil cartridge from the original pen mechanism.
It is an object of the present invention to provide a mechanical pencil mechanism or replacement cartridge that is interchangeable with a ballpoint refill produced by Cross or others, without having to change or adapt the existing pen mechanism in any way. The pencil mechanism or replacement cartridge of the invention can be inserted in a pen body in place of the refill, wherein a twist action that propels and repels the writing point will serve to propel the pencil lead from the tip of the pencil mechanism as well as propelling the writing tip or point.
Another object of the invention is to provide such a mechanism that will work in many of Cross' ballpoint pens and does not require specific extra functionality, thereby making it backward compatible to existing pens.
A still further object of the invention is to provide a pencil mechanism that replaces a ballpoint pen refill and has an actuator for containing lead with a point that is slidably mounted to the actuator and has a shoulder to engage a step in the pen when an end of the point projects from a writing end of the pen, the point having an open end for projecting the writing tip of the lead and a bushing for frictionally engaging the lead in the point to allow for, but at the same time resist, axial movement of the lead. A point spring is between the actuator and the point and biases them apart and a clutch is slidably mounted to the actuator and point. The clutch has fingers for receiving lead and the actuator engages the clutch to close the fingers and fix the lead. Further forward movement of the actuator projects the writing tip of the lead from the pen as the shoulder engages the step to fix the writing tip in a writing position. The actuator is movable rearwardly for releasing the clutch and the lead and allowing the clutch to move rearwardly in the pen for a repeat of the lead feeding cycle.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
In the drawings:
The universal pencil mechanism of the invention allows the lead in the mechanism to be held tight for use in the protracted position without having to spring back the mechanism. This means that the preexisting ballpoint pen mechanism for driving the pencil mechanism does not have to have a spring back function. The mechanism allows that the lead is not gripped during repel or at fully retracted position. In known lead feeding mechanisms the lead would be locked in the retracted position. This allows the lead to be manually pushed back into the pen in any retracted position.
This functionality is accomplished by the use of a drag bushing that provides force in the opposite direction of the movement of a clutch to cause the clutch to grip or release. Other mechanisms use a combination of stops and springs to provide a grip/release force.
Referring now to the drawings, in which like reference numerals are used to refer to the same or similar elements,
With reference now to
With reference now to
Axial force is transmitted from the pencil top 22 of the body assembly 2 by the tube 21 to the point assembly 4. The hollow tube 21 also holds spare leads shown at 10 in
Referring to
A clutch adaptor 20 is fixedly attached to the rear or top end of the clutch 13 to prevent the actuator subassembly 15, 16, 21 from separating from the clutch subassembly 13, 20. The clutch subassembly also includes a drag bushing 14 in the form of a springy spit plastic ring, attached around three axially extending and circumferentially spaced lead clutching fingers 13a of the clutch 13 such that drag bushing 14 drags against an inside surface of the point body 17 thereby providing an axial force to the clutch 13 in the opposite direction of the motion of the clutch but still allowing the clutch fingers 13a to open or close. The drag bushing 14 may alternatively be star shaped, oval or some other form than split as long as it can frictionally engage the point body surface to resist, but allow, axial motion.
Twisting the driver 107 of the pen mechanism shown in
The tube 21 moving forward relative to the point 11 causes the actuator 16 to move forwardly inside the point body 17 as well. Actuator insert 15 of actuator 16 first engages the outer inclined surface 13b of the clutch fingers 13a and moves the clutch 13 forwardly. The reacting axial force provided by the drag bushing 14 pushes the clutch fingers 13a into the plastic insert 15 of actuator 16, causing them to close by taper lock action thus gripping the lead 10 with a force greater than that provided by the point bushing/insert 12. The force of the actuator 16 pushing on the clutch 13 then overcomes the force of the drag bushing 14 causing the clutch 13 to move forward and advance the lead 10 for the remaining throw of the actuator as sequentially shown in
The clutch 13 bottoms out on the inside of the point 11 and the force provided by the pen mechanism via the tube 21 creates a reactive force from the point 11 pushing the clutch fingers 13a into the actuator 16 thus locking the lead 10 in a useable position.
A rearward axial motion of the tube 21 actuated by twisting the driver 107 of the pen mechanism in the opposite retract direction (
The point body bottoms out on the actuator restraining further axial motion between adaptor subassembly and the point subassembly such that continued rearward motion of the pen mechanism repels the whole pencil mechanism until the pen mechanism bottoms out and the point is retracted (
Repeated axial thrusts (
Referring now to
For convenience and ease of reference, following is a component list by reference numeral, illustrated in the drawings: 2 body assembly; 4 point assembly; 10 lead; 11 point; 12 point bushing; 13 clutch; 14 drag bushing; 15 actuator insert; 16 actuator; 17 point body; 18 point spring; 19 tube bushing; 20 clutch adaptor; 21 tube; 22 pencil top; 13 top spring; 24 eraser holder; 25 eraser ferrule; 26 eraser; 101 front outer pen casing; 104 anchor busing; 106 front barrel; 107 driver; and 108 shuttle.
Advantages of the invention include the fact that the pencil mechanism of the present invention is interchangeable with ballpoint refills, allowing a single writing instrument to change functions between ballpoint pen and pencil. The mechanism will work in the existing Cross helical drive ballpoint pens and does not require specific extra functionality added to the pen mechanism thereby making it backward compatible to these existing pens. Interchangeability between pen and pencil will reduce the number of different assemblies to be manufactured but still provide pencil and pen functions to the customer. The lead can be manually pushed back into the mechanism in the retracted position. The operation of the mechanism is similar to the operation of other Cross ballpoint pen products.
Currently brass, plastic and rubber components are used but any of these materials could be switched to achieve comparable results.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.