US2720795A - Machine tool guards - Google Patents

Description

Oct. 18, 1955 D. MAPSON MACHINE TOOL GUARDS l 5 ...v w n m m w L w W 0 W Oct. 18, 1955 D. L. MAPsoN 2,720,795

MACHINE TOOL. GUARDS Filed July 21, 1951 2 Sheets-Sheet 2 000000000 oooolooo 000000000 00000000@ ooooooooogodo'goooo00000 OOOOGOOOOOOOOOOOOOOOO@OOO OPOOOOOOOOOOOVOOOOOOOOOOO @rma/Eff United States Patent MACHINE Toor. GUARDS Donald L. Mapson, Los Angeles, Calif., assignor to M & D Display Mfg. Corporation, a corporation of California Application July 21, 1951, Serial No. 237,859

6 Claims. (Cl. 74-612) This invention relates to guards for protecting the operators of machine tools from injury, and it is a broad object of the present invention to provide a novel and useful guard for this purpose.

While the guard of my invention is broadly applicable to protecting the operators of various kinds of machine tools from injury, it is particularly useful for this purpose when associated with a punch press. The necessity for manually feeding the work to and from the punch and die mechanism in a punch press subjects the operator to the hazard of suffering serious hand injuries unless he is very careful. Among the measures devised to protect punch press operators from such injuries are adjustable guards which are designed to be aixed to the press so as to be disposed between the operator and the punch-die mechanism and which permit the operator a suiicient degree of visibility for him to observe the die mechanism in operation, but exclude the operators hand from access to the latter while he is feeding the Work to and from the same.

In many safety code jurisdictions, regulations have been issued requiring the use of one or the other of various types of punch press guards in connection with the operation of punch presses in that jurisdiction. These regulations have heretofore proved ineffective for one or both of two reasons. Either the guard in question interfered too much with the operators feeding the press or too much time was lost in axing it to the press, in removing it, or in re-adjusting it to tit different punch-die mechanisms, it being not infrequently necessary to change the latter several times a day in the course of operating a given press.

lt is another object of the present invention to provide a relatively simple and inexpensive punch press guard which may be quickly adjusted to conform to the varied shapes of different punch-die mechanisms, and which may be readily affixed to or removed from a punch press without disturbing the existing adjustment of the guard.

It is another object of the invention to provide such a punch press guard which is adapted for manufacture in a given size which, without any alterations thereof, will t any of a group of punch presses, the frames of which vary substantially in width.

The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings, in which:

Fig. l is a perspective view of a preferred embodiment of the invention applied to a punch press and adjusted to fit a particular punch-die mechanism Y with which said press is equipped.

Fig. 2 is an enlarged fragmentary perspective View of an upper end portion of one of the picket rods of the invention and two of the wireV clips employed in supporting these rods on the platform of the invention, one of these clips being shown in place in the uppermost of a series of annular grooves formed in said rod, while the other of said clips is positioned in the plane of another of said grooves as when being moved towards said rod to snap said clip into the latter groove.

,72,79 Patented Oct. 18, 1955 Fig. 3 is a perspective view of one of a pair of lug brackets employed in mounting the guard of my invention on a press.

Fig. 4 is a plan view of the guard shown in Fig. l with most of the rods removed therefrom, the press on which said guard is mounted being shown in section on the line 4 4 of Fig. 1.

Fig. 5 is an enlarged diagrammatic vertical sectional View taken on the line 5 5 of Fig. 4 and illustrating the guard of my invention with the platform thereof disposed horizontally and the rods thereof vertically as when said guard is supported on said brackets on said press.

Fig. 6 is a view similar to Fig. 5 and illustrates the guard of my invention tilted as when applying said guard to said press or when removing said guard therefrom.

Fig. 7 is an enlarged horizontal fragmentary sectional view taken on the line 7 7 of Fig. 5 and showing one of the wire clips of the invention slipped in place in an annular groove on one of said rods.

Fig. 8 is an enlarged fragmentary vertical sectional view taken on the line 8 8 of Fig. 4 and illustrating the con` struction of one of the spacers by which the main plates of said platform are assembled rigidly in fixed spaced relation.

Referring specifically to the drawings, the invention is therein shown as associated with a punch press 10 having a rockable frame 11 including frame side members 12 which are united by a bolster plate bed 13 on'which is bolted a bolster plate 14. The frame 11 is pivotally mounted, in a manner well known in the art on a frame base (not shown). The frame 11 is normally set to support the bolster plate 14 in horizontal position but may be released, rocked on said base and reset to vary the angular disposition of the bolster plate 14 relative to horizontal.

The front faces 15 of the members 12 have recesses 16 formed therein, inner edges of which are beveled and which receive beveled guides 17 which are secured to the members 12 by screws 18 to forrnV-shaped slideways 19 which slidably receive similarly shaped vertical lands 2G which extend laterally from a crosshead 21 of a ram 22.

The crosshead 21 has a clamp recess 30 formed therein for receiving a clamp block V31. The crosshead 21 and block 31 are semi-cylindrically recessed to receive a cylindrical punch 32 therebetween. Capscrews 33 secure the block 31 to the crosshead 21 and when tightened cause the punch 32 to be tightly clamped in a given vertical relation with the ram 22. The crosshead 21 is also provided with laterally extending vertically apertured bosses 34.

Suitable power mechanism (not shown) is mounted on the upper end of the rockable frame 11 for vertically reciprocating the crosshead 21, this mechanism being under the control of the operator by the manipulation of a foot pedal (not shown) in a manner well known in the art.

The bolster plate 14 is equipped with one or more clamps 35 which are secured to the bolster plate by capscrews 36. These clamps are for the purpose of precisely locating a die 37 on the bolster plate 14 so that this will be in alignment with the punch 32 the lower end of which is shaped to cooperate with the die in a given punch press operation. For maintaining alignment between the die and the punch, the die may be equipped with guide shafts 3S which slide in collars 39 provided on a plate 4G which is rigidly secured to the ram 22.

The preferred embodiment of the invention illustrated in the drawings comprises a punch press guard 50 which is shown as when adapted to a press operation in which the work is fed to the punch press 10 along a path indicated by the arrow A in Fig. l. When thus fed, the work generally continues intermittently through the press and out therefrom along the path indicated by the arrow B in Fig. l.

: 1 Framermernbers 12' of the punch ypress The.. guard, 50. includes a, pairV of brackets 5.1 a Platform 52 and a multiplicity of picket rods 53.

The brackets 51 are secured as by capscrews 54 to front faces 1-5 of the-punchpress. frame, side; members 12;. Bent fonwardlvfrom outerside edgesof the brackets 51' are arms 55 which have lugs 56 extending upwardly and; at aV slightly rearward inclination therefrom. The Y lugs, 56. are set. back slightly= from the front ends of arms Si to. form shoulders 57' which' are'in horizontal alignment with upper edges 58 of the arms 55.v Y TheA platform 52. is preferably of f l bricated construction as; shown in the drawings and is made, up of a pair of identical plates' and 6.6. which are joined together by the ram 22 as shownV Fig.v 4.l To accomplish this, a

recess 68 is formed. in the rear edge; of the, platform 52 to conform tovertieal upwardjprojections of the'bosses 34, a central Vrecess 69 also being provided which conforms to lthe clamp block '31 of the. ram 22.K Iheupperfaces of the bosses 34 are normally disposed slightly below the level of the platform 52. The recess 6ftVV is nevertheless shaped as shown Ain Fig. 4 to accommodate bolts and nuts which areV associated ywith the bosses 34 when the latter are employed in monnting a plate 40. on the ram 22.

The plates 65 and 6,6V are provided with like sets of Aperforati'ons 69 and 70 which are aligned respectively with each other to furnish the platform 52 with a mass of holes '71 the aves of which are normal to the plane ofthe platform. These holes are of Ya size kto Vslidably receive the rods 53 as shown in Figs. l, 5 and 6. There are al great many more holes-71 inthe platform 7.2 than there are rods 73, the reason for this Abeing* made clear hereinafter.

The plates 65 and 66 are also provided with like per-l forations 7S and 76 which are aligned respectively with Aeach other to provide a rowo'f slots 77 adjacent to and parallel with the rear edges of opposite end portions of YtheV platform 52. The slots 77 are for use in mounting the platform y52 upon the; brackets .51.,

' 1 0, are; spaced Vapart such a distance that. when the brackets 51 are affixed to these, members as shown in` this view, the lugs 56are spaced apart the same distances as the innermost pair of slots 77. Being slightly longer thanthe lugs 56 are ,vwide, slots.77 readily receive these lugs when the platform W is given a tilted position as shown in Fig. 6 and lowered until the rear edge of the plate 66v ofthe platform comes to rest on the upper edges S8 of the bracket arms 5.5. The

platform may now be released whereupon Yit will rock downward to a horizontal position of rest as shown in Fig'. 5, withftherear edges of the perforations 75 and the front edges ofthe perforations 76 of the innermost pair of slots 77 engaging the lugs 56, and with the lower plate `66 resting ,on the upper edges'58 and shoulders 57 of the V4When it is desired to remove the platform SZ'frorn this Vl'ioriiontal position of rest (Figs. l andi), the platform is merely tilted, as shownin Fig. 6, and lifted; in order to enable the operator torreadily removeY it from the punch press. Y

' The picketrods 53 are preferably cylindrical-in form and-have; a series of equally spaced annular detent grooves 86y formed inthe upper 'half of their length `which grooves are ,adapted to selectively receive spring wire clips r 81 which are of (Ll-shaped formationwith flaring tips 82 and .Outbelltz detent sections 83.= Any .of the clips 81 `is adapted to be. expanded, byf pressing Vthe daring tips 82 thereof into opposite Sides. ofone,.of theaunular grooves 80 ofeach of theY picket rods 53 with the result that this clip -ivill solid spacer columns 67,., Pins. 6,84 extend axially from i snap into place in said groove with the detent sectionsV 83V of this clip gripping this rod 53 and holding the clip assembled with the rod as shown in Fig. 7. Thus when each rod is inserted downwardly through one of the holes 7i in the platform,52 its downward Vmovement will be halted when the clip 81 thereon engages the upper surface of the plate of this platform as'shown in Figs. l, Y Y

5 and 6. The grooves 80 and clips 81 thus provide a means for limiting the downward gravitationV of the rods 53 through the holes 71 and forv supporting these rodson the platform 52 at a predetermined position in these holes when the platform 52 is lifted so as to transport the guard 50 from place to place.V

OperationV In preparing the Vguardl'i for use in guarding a punch press 10 with a new die 37 set upon the bolster plate 14,

Vsuch of the rods 53 as'are located, in'hol'es 71 of the platform 52 which would engage this die andblock the as-V sembly of the platform,V 5 2 on the Vbrackets 51 as above described, are removed from said holes Vafter whichV thek platform 52 is so assembled on the brackets 51. 4The picket rodsthusremoved are then inserted in other holes 71 to forma picket wall 90 which conforms to the front'.A outlinein plan4 of the die 37 as closely as permitted by'V the Vlimitati-ons of the patternV in which the holes 71 are formed lin the platform 5 2. The picket wall 96 is also preferably extended'inwardly at its ends over the'paths Ay and B Valong whichV the work is fed to and from the die 37.

klt is'preferableA that all of the rodrsl53 Vbe provided with clips 8 1 so as to prevent any of these'rods from dropping downwardly through its hole 71 when the platformr52` is Y lifted. as when removing the guard' Stlfrorn the punch press 10. Y

It is also preferable, in using the guard'SG, to select aY groove 3l) in which to inserta clip Sion each of the rods S3 which'will' support that rod on the platform 52V when the guard 5"() is vassembled, on the punch press 10 as shown in Fig.V rlhe grooves 'are uniformly spaced Vvapart on the rods 53a, distance which it is allowable for Y the'lower ends of theV rods V53 to be spaced above the bolster plate 14 and various portions of the `die 37 Without the guard 5,0 failing inV its function of offering a barrierV Y to theaccidental introduction ofthe fingers of the opera- "torv through the, picket wall 9.1i a sufficient distance toA cause injury.V

The reason for alternate pairs of slots `777 being provided in the platform 52 isto adapt a single guard 5i).V

to its being optionally employedvwith any of several different sizes of punch presses varying in width. The latter variations result in changes in the horizontal spacing ofthe brackets 51 and` alternate pairs of slots 77 are spaced so as (to accommodate the lugs 56 in each of the various Y spacings of the brackets 51.

Vmany diifere'ntforms of such a means which might be provided Vfor selectivel l limiting the gravitation ofthe rodsV 53 downwardly through the platform holes 71. f

' The claims are: Y

1. In a machine tool guard, the combination of; a plurality of picket rodssuflcient innumber to form a picket barrier `conforming to a given boundary outline of dangerzone, -said boundary outline being substantially :variable fin shape for different operationsto be performed yby said machine tool; and a platform, mounted when use on said tool and over said danger zone, said'platform having a mass of closely spaced rows of holes, into .anyY Y latter Y suitable selected series of which holes said rods may be inserted to unite said rods in such a barrier, which will conform to any one of a variety of danger zone boundary shapes.

2. In a guard for a punch press having a bolster plate, vertical side frame members thereabove, and a ram located between said members and mounted for vertical reciprocation relative to said bolster plate and said members, the combination of: brackets applied when in use to said side frame members adjacent a level above the uppermost position of the lower end of said ram; a platform adapted to be supported on said brackets, said platform being shaped to conform to the front and side portions of said ram and being provided with a mass of closely spaced rows of holes; and a plurality of picket rods inserted, when in use, in any suitable selected series of said holes whereby said rods are united by said platform to form a picket barrier excluding the operators hand from a danger zone between the bolster plate and ram.

3. In a guard for a punch press having a bolster plate, vertical side frame members thereabove and a ram located between said members and mounted for vertical reciprocation relative to said bolster plate and said members, the combination of: a platform adapted to be supported on said side frame members substantially parallel with said bolster plate and spaced upwardly therefrom at a level above the uppermost position of the lower end of said ram, said platform being provided with a mass of closely spaced holes, and being shaped to conform substantially to forwardly protruding portions of said ram at said level, so that portions of said platform at opposite ends thereof extend rearwardly close to said side frame members; brackets having lugs and fixed when in use to said side frame members with said lugs extending upwardly, there being vertical apertures in said platforms adapted to receive said lugs to support said platform at said level on said side frame members; a plurality of rods suicient in number to form a vertical picket barrier disposed in front of said ram and conforming substantially to a punch-die mechanism which may be fixed to and associated with said bolster plate and said ram, said holes in said platform being adapted to receive said rods to assemble the latter in the form of said picket barrier, there being an excess number of said holes permitting a substantial degree of choice in the location and conformation of said well.

4. In a machine tool guard, the combination of: a plurality of picket rods sucient in number to form a picket barrier conforming to a given boundary of a danger zone, the shape of the outline of which boundary varies substantially in different operations performed by said machine tool, said barrier being disposed between said zone and the machine operator; a platform comprising a pair of closely perforated plates; spacers rigidly uniting said plates with the latter positioned so that corresponding perforations of said plates are in axial alignment with each other, each corresponding pair of perforations forming a hole through said platform, a mass of closely spaced holes thus being provided in said platform into any suitable selected series of which said rods may be extended to unite said rods in such a barrier, in any one of a variety of danger zone boundary outline patterns; and means for mounting said platform substantially horizontally on said tool.

5. In a guard for a machine tool having a danger zone, the outline of a given boundary of which is substantially variable for different operations performed by said tool, the combination of: a platform; means for mounting said platform when in use on said tool with said platform disposed normal to the aforesaid boundary of said danger zone; a plurality of picket rods sullcient in number to form a picket barrier extending along and conforming to said boundary of said danger zone in each of the various shapes which said boundary manifests, said platform being provided with a mass of closely spaced holes into any suitable selected series of which holes said rods may be inserted to unite said rods to form such a barrier, there being such an excess number of said holes provided in said platform over and above the number of said rods required in forming said barrier as to permit said barrier to be made to substantially conform to said boundary of said danger zone in any one of the variety of shapes said boundary manifests in the different operations performed by said machine tool.

6. A combination as in claim 5 in which said picket rods are provided with longitudinally spaced grooves; and a plurality of spring clips one of which is adapted to snap onto each of said rods and fit into one of said grooves on said rod, and come to rest on the upper surface of said platform when said rod is inserted into one of said holes, whereby the distances which said rods extend respectively inwardly from said platform may be selectively determined to cause the inner edge of said barrier to conform substantially to the corresponding edge of said danger zone boundary.

References Cited in the file of this patent UNITED STATES PATENTS 482,911 Adler Sept. 20, 1892 1,228,920 Holden June 5, 1917 1,813,286 Gewalt July 7, 1931 2,621,807 Rendick Dec. 16, 1952

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