US3169511A

US3169511A - Mechanical marking instrument

Info

Publication number: US3169511A
Application number: US123679A
Authority: US
Inventors: Walter B Spatz
Original assignee: SPATZ CORP
Current assignee: SPATZ CORP
Priority date: 1961-07-13
Filing date: 1961-07-13
Publication date: 1965-02-16
Anticipated expiration: 1982-02-16

Description

Feb. 16, 1965 w. B. SPATZ MECHANICAL MARKING INSTRUMENT Filed July 13. 1961 United States Patent 3,169,511 MECHANICAL MARKING INSTRUMENT Walter B. Spatz, Los Angeles, Calif, assignor to Spatz Corporation, Santa Monica, Calif, a corporation of California Fiied'July 13, 1961, Ser. No. 123,679 4 Claims. (Cl. 120-18) The present invention relates to marking instruments and more particularly to mechanically actuated devices adapted to contain lead, crayon, brushes, scribers, and the like.

Mechanical pencils have been provided embodying a screw-type feed for advancing and retracting the lead or crayon embodied therein. The screw feed parts of such pencils have been made of metal, which are relatively difiicult and costly to manufacture. Moreover, such pencils have been composed of a comparatively large number of parts, adding to their complexity and cost of manufacture. In many types of mechanical pencils, the lead or crayon is subject to torque resulting from relative turning of the pencil parts to secure longitudinal movement of the lead or crayon, which has the obvious disadvantage of inducing breaking of the lead or crayon.

An object of the present invention is to provide a mechanical marking instrument of the screw feed type capable of advancing and withdrawing a marking element, possessing comparatively few parts, which are relatively easy and economical to manufacture and assemble.

Another object of the invention is to provide a mechanical marking instrument of the screw feed type in which all of the parts can be produced, if desired, by a molding operation in an inexpensive manner, as by making them of a suitable synthetic resin, none of the working parts being made of metal.

A further object of the invention is to provide a mechanical marking instrument of the screw feed type capable of advancing and retracting a marking element by relatively turning parts of the instrument, in which the marking element is not subject to the torque incident to relative turning of the parts.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section through a mechanical marking instrument embodying the invention, parts being shown in side elevation, and with the marking element, such as a crayon, fully retracted within the barrel of the instrument;

FIG. 2 is a view similar to FIG. 1, illustrating the marking element advanced or propelled forwardly of the instrument;

FIG. 3 is an isometric view of the rear portion of the driver or feed member of the instrument;

FIG. 4 is an enlarged longitudinal section taken along the line 44 on FIG. 2;

FIG. 5 is a cross-section taken along the line on FIG. 4;

FIG. 6 is a cross-section taken along the line on FIG. 1.

The mechanical writing instrument illustrated in the drawings includes an elongated barrel 1!) comprising a magazine or forward barrel section 11 and a rear barrel section 12. The forward barrel section terminates in a rounded nose 13 and has a noncircular bore 14 therethrough, which for example, may be pentagonal in crosssection; The rear portion 15 of the forward section is provided with a counterbore 16 receiving the forward, reduced diameter portion 17 of the rear barrel section 12. The inner end of the counterbore 16 provides a stop shoulder 18 adjacent to the forward end of the rear barrel section 12.

The'forward and rear barrel sections 11, 12 can be turned with respect to each other, but are prevented from moving longitudinally. Such action is provided by a swivel connection between the parts. As disclosed, the forward barrel section 11 has an internal circumferential rib 19 fitting within a companion external circumeferential groove 20 in the rear barrel section 12.

The rear barrel section has an internal thread or screw element 21 extending from its forward end 22 and terminating in a rear stop shoulder 23. Disposed within the rear section is a follower, feed member or driver 24, consisting of an elongate shank portion 25 and a rear head portion 26 provided with diametrically opposed longitudinal slots or grooves 27,. the

sides

28, 29 of each groove being spaced apart so as to allow the inclined internal thread 21 to pass through the groove. One face 30 of the thread will engage a rear end 31 of a groove side 28; whereas, the opposite face 32 of the thread will engage the forward end 33 of the opposite side 29 of the groove. The

sides

28, 29 of the groove are so shaped that substantially the full lateral extent of each end 31, 33 of the groove engages its

companion face

30, 32 of the thread along a line of contact, in order to distribute the load along such line of contact.

The head 26 of the driver 24 is substantially larger in lateral extent than its elongate shank 25. The shank is of noncircular cross-section, conforming to the shape of the non-circular bore 14 in the forward barrel section 11. If the bore in this latter section is pentagonal, then the cross-section of the driver shank 25 will also be pentagonal, the driver shank at all times extending into the pentagonal bore 14 of the forward section so that the two parts are keyed to one another, with the driver capable of moving longitudinally within the pentagonal bore. In effect, thedriver 24 is slidably splined to the forward, barrel section 11 and is prevented from rotating relative thereto.

The driver 24 is adaptedto occupy a rear position within the rear barrel section 12 with the rear end 35 of its head engaging the stop shoulder 23 in the rear barrel section adjacent to the end of its internal thread 21. At this time, the forward end portion 36 of the driver is still extending into the pentagonal bore, as disclosed in FIG. 1. Upon turning the rear barrel section 12 and driver 24 in the proper direction with respect to each other, the threaded engagement between the head 26 and the internal thread 21 will cause the driver 24 to advance in the-barrel, the extent of forward feeding or advancing being limited by engagement of the forward end 37 of the head with the counterbore shoulder 18 of the forward section 11, which acts as a stop.

T o prevent unthreading of the head 26 from the in ternal thread 21 of the rear barrel section 12, when the driver 24 is in its forwardmost position, the head end 37 projects forwardly beyond the forward end 33 of the groove side 29 that contacts the face 32 of the thread, so that the forward end 37 of the head engages the stop shoulder 18 with the thread 21 still fully meshed with the opposed ends 31, 33 of the groove sides. To allow the thread 21 to pass through the groove 27, the latter merges into an enlarged groove 27a, the groove 27, 27a being of the stepped configuration illustrated in the drawings. In View of the small dimensions of the parts, the making of the driver head 26 only of the length of the short side 29 of the groove 27 might result in inadvertent complete unthreading of the head from the forward end of the thread 21 when the driver 24 is in its fully advanced position. By making the head 26 of a greater length, and with the stepped groove 27, 27a, the ends 31, 33 of the sides of the groove will remain in contact with the thread rearwardly of the forward end 22 of the thread when the driver is in its forwardmost position, and with the forward end 37 or" the head engaging the stop shoulder 18 at the inner portion of the counterboreof the forward barrel section 11. The extended or greater length of the driver head 26 also enhances the stability of the driver 24 in moving longitudinally Within the rear barrel section 12.

As disclosed in the drawings, the driver 24 can advance or retract a crayon or pencil 50 connected thereto. This crayon or pencil preferably has the same configuration as the bore 14 of the forward barrel section, with suitable operating clearance therebetween. In the example shown, since the bore 14 is pentagonal in shape, the crayon or pencil t) will have a corresponding shape. Its forward end 51 is formed as a point and its rear end 52 is of reduced diameter, providing a cylindrical portion adapted to frictionally. fit within a companion cylindrical bore or socket 53 in the forward end of the driver, in order to releasably couple the pencil to the driver. If desired, the pencil or crayon 50 may be suitably attached to an adapter 54 of non-circular or pentagonal cross-section, which has the reduced diameter portion 52 piloted within the forward socket 53 of the driver 24, and making a friction fit with the socket wall. The adapter 54 and pencil 50 preferably do not have any greater lateral dimension than the driver shank 25, so that torque is transmitted between the forwardbarrel section 11 and the driver, and not between the adapter 54 or crayon 50 and the forward barrel section.

The marking instrument consist of only three parts,

the forward barrel section 11, the rear barrel section 12, and the driver or follower 24. If desired, each of these parts may be made of several pieces secured together, but, essentially, the instrument consist of the three relatively movable parts above named. These three parts can be made economically and rapidly by molding them of a suitable synthetic resin, such as styrene. The threads 21 are easily molded in the rear barrel section 12, and the driver head 26, which is to mesh with the internal thread 21, is also readily molded, the

longitudinal sides

28, 29 of each groove 27, including the side 29a of the stepped or enlarged groove portion 27a, preferably being substantially parallel to the axisof the driver, to facilitate its molding and its easy removal from the mold. The circumferential groove 20 receiving the rib 19, and which forms the swivel connection between the forward and rear barrel sections 11, 18, may be formed in the reduced diameter or forward portion 17 of the rear barrel section 12 after the latter has been removed from the mold.

In assembling the instrument, the driver head 26 is inserted into the forward portion of the rear barrel section and placed in appropriate mesh with the internal thread 21, being turned to feed rearwardly within the barrel section 12. The forward barrel section 11 is then placed over the reduced diameter portion 17 of the rear barrel section, the forward end 22 of the rear barrel section engaging the rib 19. Upon exertion of a sufiicient endwise force, the rib 19 is deflected outwardly slightly, or the forward portion of the rear barrel section is deflected inwardly sufiiciently, so that the rib 19 snaps over the end 22 of the rear barrel section and then retracts inherently into the circumferential groove 29. This can occur because of the fact that the styrene, or other plastic material, of which the parts are made has suflicient elasticity.- The forward and rearward sections 11, 12 are thereby swivelly connected to one another, their relative longitudinal movement being prevented, but their relative rotation or turning being permitted.

The driver or follower 24 is in the pentagonal bore 14 of the forward section 11. Up'on relative turning of the rear barrel section 12 with respect to the driver 24 and the forward barrel section 11, the driver is fed in a forward direction until its socket 53 is adjacent to the forward end 13 of the barrel. A crayon or pencil 50 can then be inserted in the driver socket 53, whereupon the rear barrel section 12 is turned in the opposite direction 1 relative to the forward barrel section 11 and the driver 24 to retract the latter and the pencil 59 within the barrel, the extent of retracting being limited by engage ment of the driver head 26 with the rear stop shoulder 23. The extent of forward feeding of the driver is limited by engagement of the forward end 37 of the driver head with the stop shoulder 18 at the inner end of the counterbore 16. When the driver head engages the rear stop shoulder 23, the crayon or pencil 50 is preferably disposed completely within the barrel (FIG. 1). When the crayon or pencil is to be advanced or propelled, the rear barrel section 12 need only be turned relative to the forward barrel section 11 and driver 24 a partial revolution to expose the pencil or crayon to the desired extent. Partial turning is only required, since the internal thread 21 preferably has a relatively steep pitch, and, in fact, it may be a multiple or double pitch thread. The relatively steep angle of the thread 21, which, for example, may be about 45 degrees and the use of a multiple pitch thread enables a single movement of a persons wrist to fully advance the driver 24 within the barrel and also fully retract the driver within the barrel, which, of course, will also fully advance or retract the crayon or pencil 5i) releasably coupled thereto. With the driver 24 in its fully advanced position within the barrel, the pencil or the portion of the pencil remaining may be removed from the socket 53 and a replacement pencil or crayon substituted for it, after which the driver and pencil are retracted within the barrel.

It is desirable to avoid imposing torque on the crayon or pencil, particularly when soft crayon is used, such as in connection with the use of the instrument as an eyebrow applicator. In the present case, the torque incident to relative turning of the parts to advance or retract the driver 24 and pencil or crayon 51) is not imposed on the latter, since it is the driver which is slidably splined to the forward barrel portion 11, and not the crayon or pencil. The crayon or pencil could assume any desired cross-sectional shape, preferably being made of a cross-section to conform to the shape of the bore 14 in the barrel so that the quantity of material in the crayon or pencil can be at a maximum.

Although described specifically in connection with a crayon or pencil, the instrument can be used in connection with other elements. For example, the part 50 may be a scriber having a scribing point 51, or it may be constituted as a brush in which the forward portion 51 has. suitable bristles.

I claim;

1. In a mechanical marking instrument: forward and rearward barrel sections piloted one within the other and rotatable relative to each other; said rearward section having an internal thread extending from a rear portion of said rearward section to its forward end; said forward sec-- tion having a non-circular bore; .and a driver having a shank portion of non-circular cross-section conforming to said non-circular bore and longitudinally slidable in said here and a head at the rear of said shank portion having a longitudinal groove therein receiving said internal thread, said thread engaging opposite sides of said groove, whereby relative turning between said sections feeds said driver longitudinally along said rear section and said bore, said shank portion having means at its forward end for engagement with a companion marking element; said head having a forward portion provided with a recess through which said thread extends freely and extending forwardly of the forward point of engagement between said thread and one side of said groove and adapted to engage said forward section to limit forward movement of said driver in said sections and to prevent compiete unthreading of said head from said thread.

2. In a mechanical marking instrument: forward and rearward barrel sections piloted one within the other and rotatable relative to each other; said rearward section having an internal thread extending from a rear portion of said rearward section to its forward end; said forward section having a non-circular bore; a driver having a shank portion of non-circular cross-section conforming to said non-circular bore and longitudinally slidable in said bore and a head at the rear of said shank portion having a longitudinal groove therein receiving said internal thread, said thread engaging opposite sides of said groove, whereby relative turning between said sections feeds said driver longitudinally along said rear section and said bore, said shank portion having means at its forward end for engagement with a companion marking element; stop means on said rearward section engageable by said head to limit rearward movement of said driver in said sections; said head having a forward portion provided with a recess through which said thread extends freely and extending forwardly of the forward point of engagement between said thread and one side of said groove and adapted to engage said forward section to limit forward movement of said driver in said sections and to prevent complete unthreading of said head from said thread.

3. In a mechanical marking instrument: forward and rearward barrel sections piloted one within the other and rotatable relative to each other; said rearward section having an internal thread extending from a rear portion of said rearward section to its forward end; said forward section having a non-circular bore; a driver having a shank portion of non-circular cross-section conforming to said non-circular bore and longitudinally slidable in said bore and a head at the rear of said shank portion having a longitudinal groove therein receiving said internal thread, said thread engaging opposite sides of said groove, whereby relative turning between said sections feeds said driver longitudinally along said rear section and said bore, said shank portion having means at its forward end for engagement with a companion marking element; stop means on said rearward section engageable by said head to limit rearward movement of said driver in said sections; said head having a forward portion extending forwardly of the forward point of engagement between said thread and one side of said groove and adapted to engage said forward section to limit forward movement of said driver in said sections and to prevent complete unthreading of said head from said thread; said forward portion of said head having a second groove extending from and substantially wider than said other groove and through which said thread extends.

4. In a mechanical marking instrument: a forward barrel section having a non-circular bore therethrough and a generally cylindrical counterbore providing an end wall; a rearward barrel section piloted within said counterbore; one of said sections having a circular rib received within a circular groove in the other of said sections to couple said sections longitudinally together while permitting their relative rotation; said rearward section having an internal thread extending from the forward end of said rearward section to a rear portion thereof; a driver having a shank portion of non-circular cross-section conforming to said non-circular bore longitudinally slidable in said bore and a head at the rear of said shank portion having a longitudinal groove therein receiving said internal thread, said groove being defined by opposed sides parallel to the axis of said driver engaged by said thread, whereby relative turning between said sections feeds said driver longitudinally along said rear section and said bore'; said shank portion having means at its forward end for engagement with a companion marking element; stop means on said rearward portion engageable by said head to limit rearward movement of said driver in said sections; said head having a forward portion extending forwardly of the forward point of engagement between said thread and one side of said groove and adapted to engage said end wall to limit forward movement of said driver in said sections and to prevent complete unthreading of said head from said thread, said forward portion of said head having a second groove extending from ahd sub stantially wider than said other groove and through which said thread extends.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. IN A MECHANICAL MARKING INSTRUMENT: FORWARD AND REARWARD BARREL SECTIONS PILOTED ONE WITHIN THE OTHER AND ROTATABLE RELATIVE TO EACH OTHER; SAID REARWARD SECTION HAVING AN INTERNAL THREAD EXTENDING FROM A REAR PORTION OF SAID REARWARD SECTION TO ITS FORWARD END; SAID FORWARD SECTION HAVING A NON-CIRCULAR BORE; AND A DRIVER HAVING A SHANK PORTION OF NON-CIRCULAR CROSS-SECTION CONFORMING TO SAID NON-CIRCULAR BORE AND LONGITUDINALLY SLIDABLE IN SAID BORE AND A HEAD AT THE REAR OF SAID SHANK PORTION HAVING A LONGITUDINAL GROOVE THEREIN RECEIVING SAID INTERNAL THREAD, SAID THREAD ENGAGING OPPOSITE SIDES OF SAID GROOVES, WHEREBY RELATIVE TURNING BETWEEN SAID SECTIONS FEED SAID DRIVER LONGITUDINALLY ALONG SAID REAR SECTION AND SAID BORE, SAID SHANK PORTION HAVING MEANS AT ITS FORWARD END FOR ENGAGEMENT WITH A COMPANION MARKING ELEMENT; SAID HEAD HAVING A FORWARD PORTION PROVIDED WITH A RECESS THROUGH WHICH SAID THREAD EXTENDS FREELY AND EXTENDING FORWARDLY OF THE FORWARD POINT TO ENGAGEMENT BETWEEN SAID THREAD AND ONE SIDE OF SAID GROOVE AND ADAPTED TO ENGAGE SAID FORWARD SECTION TO LIMIT FORWARD MOVEMENT OF SAID DRIVER IN SAID SECTIONS AND TO PREVENT COMPLETE UNTHREADING OF SAID HEAD FROM SAID THREAD.