Lead screw drive mechanism

March 12, 1968 w. j. barron 3,372,618

LEAD SCREW DRIVE MECHANISM Filed Jan. 18, 1966

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United States Patent Office „ , ³-³⁷²&gt;⁶¹⁸

Patented Mar. 12, 1368

2

3,372,618

LEAD SCREW DRIVE MECHANISM William J. Barron, Peru, Ill., assignor to Graphic Electronics, Inc., La Salle, Dl., a corporation of Delaware

Filed Jan. 18, 1966, Ser. No. 521,309 5

Claims. (Cl. 90—13.3)

The present invention relates to a lead screw drive mechanism for driving a pair of carriages both of which are mounted on a common lead screw which is rotatable to advance the carriages. The invention relates in particu- ¹⁰lar to apparatus for releasably interconnecting a pair of such carriages so that upon rotation of the common lead screw the carriages may either be advanced in the same axial direction or in opposite directions as required in _lgany given application.

The lead screw drive mechanism of the present invention will be described herein in conjunction with an electronic engraving machine, although it will be understood that it may have other like applications where a pair of 20 carriages are mounted on a common lead screw and it is desired to advance such carriages either in the same direction or in opposite directions. An electronic engraving machine of the type referred to above may comprise a scanning cylinder on which a photograph or other copy 25 is mounted, an engraving cylinder on which a metal or plastic plate to be engraved is mounted, a cutter for engraving the plate, and scanning apparatus for sensing the light reflected from the copy and transmitting electrical impulses proportional thereto the cutter apparatus, 30 whereby upon rotation of the scanning and engraving cylinders and simultaneous axial advancement of the scanner and cutter along their respective cylinders, the plate will be engraved with lines varying in width in accordance with the tones of the copy. 35

Where it is desired to produce an engraved metal or plastic printing plate directly from copy, the engraved plate must be “wrong reading” in order that the subject matter reproduced by the engraved plate in a subsequent printing operation will be “right reading.” Accordingly, 40 in order that the engraved plate will be “wrong reading,” the cutting apparatus and the scanning apparatus must be moved in opposite directions along their respective scanning and cutting cylinders. One method for effecting such movement is to mount two carriages on a common ,_rlead screw which is oppositely threaded at its two ends, ° whereby upon rotation of the lead screw the two carriages, one carrying the cutter apparatus and the other carrying the scanning apparatus, will be moved in opposite directions along the lead screw. However, such a lead screw ₅₀drive cannot be utilized in the foregoing manner where it is desired to produce a “right reading” engraving directly from copy. That is, in the manufacture of engraved wall plaques or scrolls or the like which must be “right reading,” it is necessary that the carriage carrying the _ggcutter and the carriage carrying the scanning apparatus be moved in the same axial direction.

It is therefore an object of the present invention to provide an improved carriage drive mechanism which can be utilized to drive a pair of carriages either in the θθ same direction or in opposite directions as is desired for a given application.

The foregoing and other objects and advantages of the invention will be apparent from the following description thereof.

Now in order to acquaint those skilled in the art with the manner of utilizing and practicing my invention, I shall describe, in conjunction with the accompanying drawing, a preferred embodiment of the invention.

In the drawings: _

FIGURE 1 is a perspective view of the front portion of an electronic engraving machine equipped with carnage drive mechanism in accordance with the present invention; and

FIGURE 2 is an enlarged exploded perspective view showing a connecting rod and associated bracket means for interconnecting a pair of carriage members so as to permit one carriage to advance the other in accordance with the present invention.

Referring now to the drawings, there is shown an electronic engraving machine comprising a base 20, a cylinder shaft 22, an engraving cylinder 24, a cutter carriage 26, a cutter head 28, a scanning cylinder 30, a scanner carriage 32, a scanner 34, motor means 36, a lead screw 38, a housing 40 which encloses a ratchet advance mechanism for connecting the motor means 36 to the lead screw 38, and thrust bearing means 42 for supporting the lead screw 38. The motor means 36 rotates the shaft 22 and the cylinders 24 and 30 mounted thereon, and the ratchet mechanism (not shown) disposed within the housing 40 is utilized to connect the motor to the lead screw 38 for intermittent rotation of the lead screw in one direction. The lead screw 38 has oppositely formed threads at its two ends 38α and 386 whereby upon rotation in the direction it is driven by the motor 36 it will advance the cutter carriage 26 and the scanner carriage 32 towards one another. In this manner, the scanner 34 will scan copy mounted on the scanning cylinder 30 and transmit electrical impulses to the cutter head 28 for engraving a plate mounted on the engraving cylinder 24. For a more complete description of an electronic engraving machine of the foregoing type, reference may be had to my U.S. Patent 3,183,745, issued May 18, 1965, and assigned to the assignee of the present invention.

The cutter carriage 26 has a manually operable lever or handle 44 thereon for controlling engagement of the carriage with the lead screw 38, and a similar manually operable control lever 46 is provided on the scanner carriage 32. Accordingly, when the two levers 44 and 46 are both in their down or operative positions, such as shown with respect to the lever 44 in FIGURE 1, then both of the carriages 26 and 32 will be operatively engaged with the lead screw 38, in particular with the respective oppositely threaded end portions 38α and 386 thereof. Thus, rotation of the lead screw by the motor 36 and associated ratchet mechanism 4(1 will advance the two carriages toward one another. Either of the carriages 26 and 32 may be disengaged from the lead screw 38 by moving the corresponding control lever to an upper inoperative position, as shown for example with respect to the control lever 46 in FIGURE 1.

In accordance with the present invention, a connecting rod 48 is provided for interconnecting the two carriages 26 and 32 in order that one carriage may drive the other. Thus, a mounting bracket 50 is screwed or otherwise fixedly secured to the top of the carriage 26, and the bracket 50 is provided with a pair of spaced apart upwardly extending lugs 52 and 54 having aligned horizontal mounting holes 56 and 58 formed therein respectively for receiving the ends of a mounting pin 60. One end of the connecting rod 48 has a transverse hole 62 formed therein, and the pin 60 is positioned so as to pass through the aperture 62 with its ends disposed in the lug mounting holes 56 and 58, whereby the one end of the rod 48 is pivotally supported at the mounting bracket 50.

A second mounting bracket 64 is screwed or otherwise securely fastened to the top of the scanner carriage 32, and the bracket 64 includes an upright mounting post 66 having a horizontal bore 68 formed therein for receiving the right hand end of the connecting rod 48. In addition, a set screw 70 is threaded downwardly into the top of the post 66 so as to communicate with the bore 68. In this manner, when the end of the rod 48 is positioned in the bore 68, the set screw 70 may be

3.372,618 ' 4 ends for advancing said carriages in opposite directions upon rotation of said screw, and manual control means on each carriage for selectively engaging and disengaging the same with said lead screw, the improvement com5 prising, in combination, first mounting means on one of said carriages, second mounting means on the other of said carriages, and a rigid connecting member extending between said first and second mounting means, one end of said connecting member being secured to said jq first mounting means, and the other end of said connecting member being releasably secured to said second mounting means, whereby upon engagement of a selected one and disengagement of the other of said manual control means and rotation of said lead screw the engaged 15 one of said carriages will be advanced by said lead screw and will act through said rigid connecting member to advance the other of said carriages in the same direction.

2. The invention of claim 1 wherein said second mounting means is adjustable relative to said other end of said 20 connecting member to permit adjustment of the spacing between the two connected carriages.

3. The invention of claim 1 wherein said one end of said connecting member is pivotally secured to said first mounting means whereby when not in use said other 25 end may be released from said second mounting means and said connecting member pivoted to a storage position while remaining secured to said first mounting means.

4. In an engraving machine of the type having a cut30 ter carriage and a scanner carriage mounted on a common lead screw which is oppositely threaded at its two ends for advancing said carriages in opposite directions upon rotation of said screw, and manual control means on each carriage for selectively engaging and disengag35 ing the same with said lead screw, the improvement comprising, in combination, first mounting means including pivot pin means on one of said carriages, second mounting means including releasable clamping means on the other of said carriages, and a rigid connecting mem40 ber extending between said first and second mounting means, one end of said connecting member being pivotally secured to said first mounting means by said pivot pin means, and the other end of said connecting member being releasably secured to said second mounting 45 means by said clamping means, said second mounting means being adjustable relative to Said other end of said connecting member to permit adjustment of the spacing between the two connected carriages, whereby upon engagement of a selected one and disengagement of the 50 other of said manual control means and rotation of said lead screw the engaged one of said carriages will be advanced by said lead screw and will act through said rigid connecting member to advance the other of said carriages in the same direction.

⁵⁵ 5. The invention of claim 4 wherein said second mounting means comprises a mounting member having a horizontal opening therethrough for receiving said other end of said connecting member arid permitting the same to project through said mounting member a ⁰⁰ desired distance, said releasable clamping means extending transversely to said opening and in communication therewith so so as to releasably clamp against a portion of said connecting member disposed in said opening.

No references cited

LEONIDAS VLACHOS, Primary Examiner.

utilized to clamp down on the rod and lock the same in position. It will be noted that the carriage 26 further includes a conventional hand wheel 72, and the carriage 32 includes a similar hand wheel 74, such hand wheels being manually operable to move the respective carriages in any desired direction when they are disengaged from the lead screw 38. Thus, one or both of the hand wheels may be manually operated in order to position the carriages when the connecting rod 48 is being operatively secured to the right hand bracket member 64.

It will be understood from the foregoing that when it is desired to operate the engraving machine so that the two carriages 26 and 32 will advance in the same direction, one of the carriages, for example the scanner carriage 32, is disengaged from the lead screw 38 by moving the lever 46 to its upper inoperative position as shown in FIGURE 1. The connecting rod 48 is then pivoted to a horizontal position, and by manipulating the hand wheel 74 so as to manually advance the carriage 32 toward the carriage 26, the right hand end of the rod 48 is caused to project through the bore 68 in the mounting post 66. It will be necessary to position the two carriages 26 and 32 at varying distances apart depending upon the particular engraving job to be performed, but once the carriages are spaced apart as desired with the right hand end of the rod 48 extending through the bore 68 in the post 66, the set screw 70 is tightened to lock the end of the rod in position and thereby rigidly interconnect the carriages.

In the example being described, lever 44 associated with the cutter carriage 26 may be left in its downward or operative position so that the latter carriage is engaged with the lead screw 38. Accordingly, when the lead screw is rotated so as to move the cutter carriage 26 to the right, the carriage 26 will act through the connecting rod 38 to push the scanner carriage 32 to the right. In the particular machine being described herein the motor 36 and ratchet mechanism 40 are adapted to rotate the lead screw 38 in only one direction. However, various drive means may be utilized for driving the lead screw in either direction, and it will be understood that in whichever direction the carriage 26 is driven, the latter will act through the rod 48 to move the other carriage 32 in the same direction. Moreover, by moving the lever 44 to its disengaged position and moving the lever 46 to its engaged position, the lead screw 38 will drive the right hand carriage 32 which in turn will act through the rod 48 to move the carriage 26 in the same direction. When it is desired to have the two carriages 26 and 32 advance in opposite directions, both levers 44 and 46 are moved to their engaged positions and the set screw 70 is loosened so as to disengage the end of the rod 48 from the supporting post 66. When not in use, the rod 48 may simply be pivoted in a counterclockwise direction to an out of the way position, while remaining pivotally connected to the bracket 50 so as to be readily available for use when desired.

While I have described my invention in a preferred form, I do not intend to be limited to such form, except insofar as the appended claims are so limited, since modifications coming within the scope of my invention will readily occur to others, particularly with my disclosure before them.