US2343044A - Rack repairing mechanism - Google Patents

Description

Feb. 29, 1944.

W. F. BRUGMANN RACK REPAIRING MECHANISM ori inal Filed April 25. 1936 INVENTOR. Z/fiZUamFBrQgman/z BY Patented Feh 29, 1944 UNITED STATES ....PAT ENT OFFICE lines, REPAIRING MECHANISM Original application April 25, 1936, Serial No. 76,454. Divided and thi s'apl l catlon July 11,

1940, Serial No. 345,017

. 9 Claims.

-.This invention relates in generalito printing plate mounting devices, such as those employing the type of rack adapted to be secured in grooves therein disclosed in my co-pending application Serial No. 76,454, filed April 25, 1936, and issued August 6, 1940, as United States Letters Patent No. 2,210,749, and it relates more particularly to the apparatus for repairing such racks. The present afgliation is a division of said Patent No. 2,210,-

While the instant invention is clearly applicable to printing press plate cylinders and to plate supporting bases for flat bed presses, it is shown and described herein in cpnjunction with the former, since its advantages'in such an installation ,are 7 more readily apparent.

The prior art discloses the cutting of helical grooves in-the circumferential surface of printing press cylinders within whichregister hooks are adapted to be mounted, and the provision of a rack or. racks therein with which driving means,

such as gears or worms, in the hooks may cooperate to move the hooks longitudinally of the grooves into and out of clamping engagement with the usual printing plates. These prior art racks how ever, and the methods employed in mounting them in the grooves in the cylinders have certain prac-' tical disadvantages which it is the purpose of the "instant invention to overcome.

Heretofore the .racks have been pushed or pulled longitudinally into T-slots cut adjacent the bottom of the grooves. Since the racks are subjected to great strain by the driving elements oi} the hooks both in'their initial registering'move ments, and during a why the action orthe impression cylinders on the printing plates-undue wear of certain portions of the racks and breakage of some of the teeth thereof naturally follow in the course of time. In the prior art devices it is then necessary to remove the .entire rack from the full length of the groove, even though but a small portionthereoi has been damaged. To do I this, the plate'cylinder must be taken out of the press and shipped to the factory where the neces-' sary tools and equipment are available to do the work, and, in the meantime, the press is com-' pletely out 01' commission.

The parent case, of which this application'is a division, discloses a novel rack and method and apparatus for inserting the same in a groove in 'a printing plate cylindenirom the top of the groove. and riveting it in the bottom portion thereof. This novel rack is designed to. eliminate the above described disadvantages in repairing any desired portions thereof, and the instant applicatlon deals more particularly with such restood from the following description, which, when taken in connection with the accompanying drawing, discloses a preferred embodiment thereof.

In the drawing,

Figure 1 is a top plan view of a repair drill jigmounted in operative position in a groove of a printing plate cylinder;

Figure 2 is a vertical sectional view taken substantially on the line 2- 2 of Fig.1;

Figure 3 is a vertical section taken substantially ontheiine3.3o'fFig.1; v

Figure 4 is a top plan viewof a trimming tool mounted in a groove of the cylinder;

Figures 5 and 6 are vertical sectional. views taken substantially on the lines 55 and, 8%, respectively, of Fig. 4;

Figure? is a front elevational view of a repair riveting tool;

Figure 8 is a bottom plan view of the tool of Figure 9 is a top plan view of a repair piece for the rack.

Referring more particularly to Figs. 1 to 6 of the drawing, portions of a printing press plate supporting cylinder 2| of well-known construction are disclosed which is provided in the usual manner with a plurality. of spaced, parallel,

helical grooves 23 cut in the circumferential surface thereof. The cylinder 2| is thesameas that 7 more fully illustrated in the parent application hereinbefore referred to.

The grooves 23 are constructed to receive any suitable form of plate holding devices, such as the printer's .register hook disclosed in my prior United States Letters- Patent-No.2,124fl28, issued July 26, 1938, and are provided von each side adjacent the .top with longitudinal, under-cut recesses 24 within which the locking elements of the plate holding devices (not shown) are adapted tobe' positioned. At

their lower ends, the side walls of the grooves 23 to are cut back or outwardly at a slight angle and and with longitudinal, marginal recesses 23 on either side of and extending slightly below. the root line or bottom portion of the teeth 21. The

parent Patent No. 2,210,749 discloses means for inserting a rack 23 into a groove-23 from the top thereof and rigidly securing the rack in the bottom of the groove by displacing parts of the marginal portions of the rack laterally into the inclined recesses23 at the bottom of the groove. When the racks 23 are secured in place in the bottom of the grooves 23, the marginal recesses 23 form gutters alongthe sides of the teeth 21 for the accumulation and drainage of foreign matter, as well as facilitating the securing of the racks within the grooves 23. The racks 23 are also preferably provided with a substantially centrally located, longitudinal recess or groove 23 in the bottom surface thereof for a purpose which will beexplained hereinafter.

It is of course necessary in inserting the racks as described in the parent case, to remove the printing plate supporting cylinder from the press. After the cylinder has been mounted in the press, however, the racks 23 may be repaired by use of the mechanism shown herein without'removing the cylinder therefrom.

Referring more particularly to Figs. 1, 2 and jacent each end, the lower portion of the jig 32 is provided with a recess 33, which communicates at its upper end with a vertical bore 33.

A clamping bolt 31 is mounted in each ofthe bores 33, and is provided at its lower end with an elongated head portion 33 disposed within the 'a, a drilling jig 32 is shown which is substantially gagement with the'undercut recesses in the groove 23.

The nuts 33 are then tightened to bring the head portions 33 upwardly into firm locking contact with the top walls of the recesses 23 and force the teeth 33 downwardly into the spaces between the teeth 21 of the rack;

The apertures or bores 32, 32* and 33 are all used as guides for a drill of any suita'ble construction. The drill will cut downwardly through therack 23, with the groove 23 in the bottom portion thereof insuring that the rack is completely cut through without damaging the lower surface of the groove 23. It is preferred that a bottoming drill be employed, and a suitable stop collar may be set thereon -to limit downward movement of the drill by contacting the upper surfaces of the jig 32. This operation having been performed, the jig 32 is removed from the groove and reversed end for end and replaced in contact with the same portion of the rack that it engaged in its first position. The same drilling operation, using ,all of the apertures 32, 32' and 33, is then repeated. 1

The apertures 32 and 32' are spaced so that 25 the center lines of adjacent apertures are a dis-.

tance apart slightly less than twice their diam-' eters. Consequently, these two drilling operations will result in eight overlapping holes being cut through the center of the rack, as determined by apertures 32 and 32', to completely cut away the by the end aperture 32 will have its center line a recess 33; The upper .end of each of the clhmping bolts 31 is threaded for engagement by a nut 33, and is provided with an angular, axially disposed recess or bore 3| (Fig. 1). ,The center portion of the jig 32 is provided with a plurality of longitudinally spaced boxes or apertures 32 and a similar aperture 32' at one end thereof,

the vertical axes of all of which apertures coincide with the.longitudinal axis of the jig. Two additional bores or apertures 33- are provided ad-. jacent the end aperture 32 furthest from aperture 32, which are spaced to'either side thereof and have their center lines disposed on a cross line at the same angle as the teeth 33 and 21.

When it is desired to repair a particular portion of one of the racks 23, the drilling jig 32'Iis inserted into the groove 23 over that portion 'of the rack which is to be repaired. The teeth 33 of the jig insure its being properly pomtioned relative to the teeth 21 of the rack 23. A key or tool (not shown) is inserted in the angular re- .cesses "to turn the clampingbolts 31. A partial rotation of the clamping bolts 31 will turn the elongated head portions 33 thereof into enens-ornie clamping bolt m. The members m,-

center portion of that part of the rack 23 which is being repaired. The jig 32 will be so placed in its reversal between drilling operations, that thehole that is cut through the rack as determined on the same line as the holes determined by the guide apertures 33 in thereverse position of the jig 32, because the transverse center line of apertures 33 is spaced from that of aperture 32 adiacent thereto a distance slightly less than the diameters of these apertures. The end portions of that part of the rack 23 being cut out will thus be cut away as shown at 33 in Fig. 4.

A trimming jig, indicated generally by reference-numeral 33, is then employed to square 01! the jagged end portions 33, of that part of the rack 23 remaining in the groove 23. Referring more particularly to Figs. ,4 to 6, the trimming jig 33 is rectangular in shape and of such a size as to fit loosely within the groove 23. The jig 33 is provided withv an upper marginal flange 33, whichisadaptedtorestuponthetop surfaceof the plate supporting member 2| when the jig is positidhed in the groove 23. The bottom surface of the 11 u isprovided with a plurality of teeth 31, which are adapted to engage between the teeth 21 of the rack 23 on one side'or the other of that portion of the rack which has been cut away in the drilling operation. I

The ll: 33 is provided with'a recess 33 in its lower portion whichv communicates with a vertical bore 33 having a clamping bolt Ill extended therethrolllh. The boltlll is provided with an elongated head portion I32 at its lower end, and

is threaded adjacent its upper end for engagement with a locking nut I33. An angular recess or borel33 extendsdownwardly into'the upper I32 and III are substantially identical, both in form and function, to'the members 31, 33 and '33 ofthedrillingilsfl.

One of the lower corners of the trimming'jig 33 is cut away at I33 (Fig. 3) and avertical bore extendsthro llhtheiliiladlacenttherearend of this cut-awayportion. The lower end of the from with a magnet.

bore I06 is enlarged to provide an angular chamber within which is slidingly positioned the lower rectangular head portion of a chisel or cuttin member I01, which terminates at its lower end in a blade I08. The upper end of the chisel I01 5 is threaded and extends above the top surface of the jig 95. A bolt 409 is screwed on the upper end of the,chise1 I01 to limit the downward movement thereof, and is held in set position by a locking nut III.

The trimming jig 95 is positioned in the groove 23 in the same manner as the drilling jig 82., The teeth 91 insure proper longitudinal positioning of the jig, so that the blade I08 of the chisel I01 will be directly above the side surface of the last l5 remaining tooth 21 of the rack 26 adjacent the cut-away portion thereof. Since the blade I oi the chisel is disposed at the same angleas the teeth 01 and 21, asharp blow imparted to the chisel will cleanly trim off the jagged edges .04 2

bottom of the groove 23 after the drilling and trimming operations have been performed, may be blown out of the groove orremoved there- A repair piece II2 (Fig. 9), shaped to flt exactly in the blank spacein the rack 20 resulting from the above drilling and trimming operations, is inserted into this space in the bottom of the groove 23, and riveted in place with a hand rivet- 35 ing tool, such as that disclosed in Figs. 7 and 8 and indicated by reference numeral H3.

The tool H3 is substantially square in cross section, and is cut away at its-bottom endto provide a transverse recess I I4. Depending from 40 the bottomof the tool on either side of, the recess Ill are longitudinally d isposed teeth H5. The teeth II have a vertical cross-sectional shape similar to the teeth 10 of the riveting roller 14 of the parent case. The recess I I4 is of substantially the same width as the tooth 21 of the rack,

so that the tool II3 may be disposed in the slot '23 with the teeth II5 straddling the centralpor tion of the repair piece I I2. Downward pressure on the tool II3 will spread some of the metal of the marginal edges'oi the repair piece into the through ythe-rack. The same result could be obtained by cutting a'recess in the bottom surface of the groove 23. The above described arrangement, however,. isoobviouslv much more desirable. 1 v

Should it be necessary to put'in a much longer repair piece than that shown in Fig. 9, it would.

perhaps be easier to'cut oil the ends of the piece in the manner above described, andthen'cut through it longitudinally with a saw or narrow" milling cutter operating in azsuitable fixture. l0

Regardless of the method-employed, the longitudinal cutting through of the rack 26 permits it to be readily pulled out from under the angular recesses 25 in the groove 23. These recesses need not be very deeply cut into the sides of the or ea ap tu slightly less t the d me? f groove. a few thousandths of aninch being suf flcient to rigidly secure the rack in the bottom of the groove.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing. description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A tool guiding device for repairing racks mounted in grooves in -a printing plate supporting member, comprising a body portion adapted to be positioned in.-'-a said'groove and having an extension from one surface thereof adapted to engage between the teeth of the rack in said groove, said body portion also having tool guiding means associated therewith, and means for "securing said body portion in selected position in said groove so that said tool guiding means is disposed in a desired relationship to the teeth of said rack.

2. A drilling iig, comprising a body portion adapted to ,be positioned in a groove in a printing. 1

plate supporting member and having drill guiding bores extending therethrough, teeth on the lower surface of said body portion adapted to mesh with a rack in said groove, and means mounted insaid body portion for securing said Jig in selected position in said groove.

3. A trimming tool, comprising a body portion adapted to be positioned in a groove in a printing plate supporting member; teeth on the bottom surface of said body. portion adapted to mesh with a rack in said groove, a cutter slidably moimted in said body portion, and means mounted in said'body portion for securing said tool in selecteclj position in said groove.

4. A tool guiding device for repairing a toothed rack secured in the undercut bottomportlon of a groove having recesses in the side walls thereof, comprising a body portion positionable in said groove and having teeth on the bottom surface thereof adapted to mesh with the teeth of said rack to properly position the device longitudlnally of the groove, said body cportion also having tool guiding means associated therewith, and means mounted in said body portion and adjustable relative thereto for engaging the recesses in the side walls of thegroove to prevent vertical.

displacement of the device therefrom so that said toal guiding means is disposed in a desired relationship to the teeth of said rack.

5. A drilling Jig, comprising a body portion positionable in a groove having a toothed rack secured therein, means for removably securing said body portion in said groove, apertures spaced from each other longitudinally of said body portion slightly less than twice each of their diam- .eters, other apertures having the same diameter disposed to either side of an end one of said longitudinally spaced apertures and ,formed on a transverse axis'spaced slightly less than said di with the teeth of said rack,-said teeth and said-= apertures being so positioned relative to each other as to enable end for end reversal of said body portion in'said groove to place the-center:

oi! said groove;

4- m: from as original P ition mam s. A'trimmingm dimprlsingabodyportion positionable in a groove having a' toothed rack secured therein, means for removably securing said body portion in said groove, ajcutter slidably mounted in said body portion, andvteeth formed on said body portion to mesh with the teetho! said rack, said teeth and said cutter being so,

positioned relative to each other as to bring the latter substantially in the plane of the side air 'iace'oioneoitheteethoi'theraek.

7. A tool guiding device for repairing a toothed rack mounted in a groove, comprising a body portion positionable in said groove and having means adapted to engage the teeth oi said rack properly position the device'relative to a selected portion oi said body portion also having tool guiding means associated therewith. and lockingmeans mountedlnsaidbodyportion and operable toengage said groove to prevent displacement of the device relative to said rack sothat said tool guiding means is disposedin a (1981M l'QllflOhBhiP t0 the teeth 0! said ml 8. A drilling Jig, comprising a body portion positionable in a groove having a toothed rack 1 mounted therein, said body portion having a drill guiding bore extending therethrough, means nted to enga e the teeth of said rack to prop erly position said bore relative thereto, and looking means operable to engage said groove to prevent displacement of the tool relative to said rack.

9. A jig for use in repairing a toothed rack mounted in a groove, comprising a body portion with tool guiding means and having means for engaging the teeth oi said rack to properly position the jig relative to a selected portion oi the wrnmm 1". nniiamum-

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