Abstract:
An apparatus for guarding an operator from hazards produced at the point of operation of a machine tool. The apparatus comprises a mounting bracket for attaching the fixture to the dovetail of the ram of a milling machine (e.g., a Bridgeport vertical milling machine), the mounting bracket having a first end and a second end; a swing arm attached to one of the ends; and a guard attached to the swing arm. In some embodiments, a second swing arm attached to the other of the ends supports a second guard or a tube that carries oil to the work piece.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     This invention relates to a fixture for a milling machine. In particular, the invention relates to a chip guard and the milling machine equipped with the chip guard. 
     It is considered good practice to shield machine operators from workplace hazards. The Occupational Safety &amp; Health Administration (OSHA) of the U.S. Department of Labor, in Standard No. 1910.22, requires that one or more methods of machine guarding be provided to protect operators from hazards associated with machine tool operation. For these reasons, a variety of guard designs have been developed. The background art is characterized by the inventions described in U.S. Pat. Nos. 1,527,998; 1,563,887; 3,703,124; 3,837,383; 4,043,701; 4,126,081; 4,132,497; 4,162,647; 4,290,717; 4,543,012; 4,543,021; 4,552,494; 4,884,927; 5,103,541; 5,218,887; and 5,479,837; the disclosures of which patents are incorporated herein as if fully set forth. 
     Serpico in U.S. Pat. No. 1,527,998 discloses a protective guard for a router. This invention is limited in that it must be attached to the router rod portion of the router. The invention is further limited in that the glass guard can only be pivoted about a horizontal axis. 
     Wiespetat in U.S. Pat. No. 1,563,887 discloses a drill press guard. This invention is limited in that the guard must be attached to the feed rack or quill of the drill press. 
     Smith et al. in U.S. Pat. No. 3,703,124 disclose a machine tool guard and/or safety guard. This invention is limited in that it is attached to a slot in the table of the machine tool and does not effectively protect the user when the tool is raised above the surface of the table. 
     Ko in U.S. Pat. No. 3,837,383 discloses a dust collector and safety guard. This invention is limited in that it is attached to the machine tool by means of a flange that must be fixed to the machine. 
     Jaeger in U.S. Pat. No. 4,043,701 discloses a safety shield assembly. This invention is limited in that it is attached to the machine tool by means of a bracket. 
     Zdeb in U.S. Pat. No. 4,126,081 discloses a safety shield for a machine tool. This invention is limited in that the safety shield must be attached to the quill of the milling machine. The invention is further limited in that the panels of the shield can only be pivoted about a horizontal axis. 
     Weller et al. in U.S. Pat. No. 4,132,497 disclose drilling machines and guards therefor. This invention is limited in that it must be attached to the quill of a vertical milling machine. 
     Aslen in U.S. Pat. No. 4,162,647 discloses a guard for a milling machine that comprises a combination of rods and blocks supporting guard panels relative to the milling tool. In one embodiment, the invention of Aslen comprises a plurality of mounting bars that are attached to the dovetail of a milling machine ram by means of clamping blocks secured in place with clamping bolts. Each mounting bar supports a pair of mounting blocks from which support rods extend into support blocks. A mounting rod extends downward from each support block to which an attachment block is secured. Each pair of support blocks a guard panel. This invention is limited in that multiple mounting bars, mounting blocks, support blocks and attachment blocks are required. The requirement for multiple mounting bars and blocks means that the device cannot be attached to the end of the dovetail when the ram is moved backward leaving only a short portion of the dovetail forward of the turret, which is normally the case. The invention is further limited in that planar guard panels are provided, which panels can only be pivoted about a horizontal axis. 
     Aslen in U.S. Pat. No. 4,290,717 discloses machinery safety guards. This invention is limited in that it must be attached to the barrel of a vertical milling machine. 
     Adler in U.S. Pat. No. 4,543,021 discloses a safety shield for a machine tool. This invention is limited in that it must be connected by a series of rods, links, knuckle joints, etc. to an existing hole in a Bridgeport type milling machine. 
     Wix in U.S. Pat. No. 4,552,494 discloses a collapsible safety shield for a vertical drill press. This invention is limited in that it must be attached to the drill housing. 
     Menker in U.S. Pat. No. 4,884,927 discloses a shield unit for a machine tool. This invention is limited in that it must be attached to the machine tool&#39;s spindle adjustment rod. 
     Ferletic in U.S. Pat. No. 5,103,541 discloses a milling machine stop bar for use with reversing tapping attachments. The stop-bar is clamped onto the ram of the milling machine. This invention is limited in that it does not provide a guard for protection of the machine operator. 
     Ziobro in U.S. Pat. No. 5,218,887 discloses a drill chuck and revolving spindle guard. This invention is limited in that the safety shield must be attached to the quill of milling machine. The invention is further limited in that the guard cannot be repositioned vertically. 
     Kyle in U.S. Pat. No. 5,479,837 discloses a guard for a channel bed press. This invention is limited in that it attaches to the rear channel on the channel bed of such a press. 
     The inventions in the related art exhibit one or more limitations. Many related art milling machine guards attach to the quill, quill housing, barrel, etc. of the machine, parts which are tilted from the vertical or moved relative to the workpiece during some machine operations. Under these conditions, the related art guards can interfere with the operations and the guards can be rendered less effective by their orientation or distance from the workpiece. The related art fixtures that attach to the dovetail of the milling machine ram are overly mechanically complex and, hence, expensive to manufacture and difficult to use, not designed to be attached to the end of the dovetail or fail to guard the operator. None of the related art fixtures can be moved out of the way when not required. Furthermore, none of the related art fixtures direct oil to the cutting face. 
     BRIEF SUMMARY OF THE INVENTION 
     The purpose of the invention is to deflect chips that are produced during a milling operation and generally to facilitate the milling operation and protect the machine operator from rotating parts, flying chips and sparks. One advantage of the invention is that it is mechanically simple (comprises relatively few parts) and simple to use. Another advantage is that one or more of the guarding means (arms and guards) can be rotated (swung) out of the way when not required. Another advantage of the invention is that the guard is attached to the milling machine at a point that does not move when the quill moves. 
     One object of the invention is to deflect chips produced during a milling operation. Another object of the invention is to shield a machine operator during a milling operation. A further object is to direct oil to a cutting face. 
     The invention is an apparatus for guarding an operator from hazards produced at the point of operation of a machine tool. The apparatus comprises means for attaching a fixture to the dovetail of the ram of a milling machine (e.g., a Bridgeport vertical milling machine), said means for attaching having a first end and a second end; a swing arm attached to one of said ends; and guarding means attached to said swing arm. In some embodiments, a second swing arm attached to the other of said ends supports a second guarding means or a tube that carries oil to the work piece. 
     In use, the invention is operated by sliding a mounting bracket onto the dovetail of a ram of a milling machine and by securing the mounting bracket on the dovetail by means of a vertical set screw that is threaded into the mounting bracket. Each of the arms of the device are then swung forward (and raised or lowered, if necessary) to position the guards between the machine operator and the point of operation. Each of the arms is then secured in place by means of a horizontal set screw on the mounting bracket. For the purposes of this disclosure, the term “vertical” means generally in a plane transverse to the longitudinal axis of the bracket with a general up and down orientation and the term “horizontal” means generally in a plane parallel to the longitudinal axis of the bracket with a general side to side or back to front orientation. 
     In broad terms, a preferred embodiment of the apparatus is a device for deflecting chips produced by operation of a milling machine, said milling machine having a ram with a dovetail, said device comprising: a bracket that is slidably mountable on said dovetail, said bracket having a first end and a second end; a first swing arm that is rotatably attachable to said bracket adjacent said first end; a second swing arm that is rotatably attachable to said bracket adjacent said second end; and a pair of deflectors, one of which is attachable (preferably slidably attachable) to said first swing arm and the other of which is attachable (preferably slidably attachable) to said second swing arm. 
     Another preferred embodiment of the invention is a point of operation guard for use on a milling machine having a ram on which the head of the milling machine is mounted, said ram being attached to the column of the milling machine by means of a dovetail slide, said dovetail slide having a mortise portion that is attached to said column and a tenon portion that is attached to said ram, said point of operation guard comprising: a body having a mortise therein that is slidably mountable on said tenon portion, said body having a first end and a second end; a first arm that is rotatably attached to said body adjacent said first end; and a first deflector attached to said first arm. In an alternative embodiment the above point of operation guard also comprises: a second arm that is rotatably attached to said body adjacent said second end; and a second deflector attached to said second arm. 
     In another alternative embodiment, the above point of operation guard also comprises: a solid thumb screw that is screwed into a first threaded hole in said body and that impinges on said tenon portion when said body is mounted on said tenon portion. In another alternative embodiment, the above point of operation guard also comprises: a first nylon- or brass-tipped thumb screw that is screwed into a second threaded hole in said body and that has a first nylon or brass tip that impinges on said first arm when said arm is inserted through a first unthreaded hole in said body; and a second nylon- or brass-tipped thumb screw that is screwed into a third threaded hole in said body and that has a second nylon or brass tip that impinges on said second arm when said arm is inserted through a second unthreaded hole in said body. In another alternative embodiment, the invention is the above point of operation guard wherein said first deflector and said second deflector each comprise a flexible plastic member having a longitudinal hole therein; and wherein said first arm and said second arm are fitted through each hole. In another alternative embodiment, the invention is the above point of operation guard wherein an end of each arm that protrudes through said unthreaded holes in said body is fitted with a cap made of a resilient material (e.g., rubber). In another alternative embodiment, the invention is the above point of operation guard wherein said body is comprised of two pieces, with each piece forming a part of the mortise and wherein said pieces are connected by a bolt that is used to adjust the effective width of said mortise. 
     In another preferred embodiment, the invention is a milling machine comprising the above apparatus for guarding an operator or point of operation guard. The milling machine further comprises a base, a column resting on said base, said column supporting a turret having a tenon portion of a dovetail slide, a table resting on a knee which rests on a pedestal that extends upward from said base, a ram having a mortise portion of the dovetail slide, and a head attached to said ram, said head having a quill and a spindle. 
     Further aspects of the invention will become apparent from consideration of the drawings and the ensuing description of preferred embodiments of the invention. A person skilled in the art will realize that other embodiments of the invention are possible and that the details of the invention can be modified in a number of respects, all without departing from the inventive concept. Thus, the following drawings and description are to be regarded as illustrative in nature and not restrictive. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The features of the invention will be better understood by reference to the accompanying drawings which illustrate presently preferred embodiments of the invention. In the drawings: 
     FIG. 1 is an elevation view of a milling machine with a preferred embodiment of the point of operation guard installed. 
     FIG. 2 is a perspective view of a first preferred embodiment of the device before it has been attached to a milling machine. 
     FIG. 3 is a perspective view of a second preferred embodiment of the device before it has been attached to a milling machine. 
     FIG. 4 is a perspective view of a preferred embodiment of the mounting bracket. 
    
    
     The following reference numerals are used to indicate the parts and environment of the invention on the drawings: 
       8  milling machine 
       10  chip deflector 
       12  mounting bracket 
       14  first pivot arm 
       15  first rubber cap 
       16  first plastic guard 
       18  second pivot arm 
       19  second rubber cap 
       20  second plastic guard 
       22  mortise 
       24  first part 
       26  second part 
       28  threaded rod 
       30  tenon 
       31  centerline 
       32  ram 
       34  vertical thumb screw 
       36  first vertical segment 
       38  first horizontal thumb screw 
       40  second vertical segment 
       42  second horizontal thumb screw 
       44  first horizontal portion 
       46  second horizontal portion 
       48  first curved portion 
       50  second curved portion 
       52  source of oil 
       54  first vertical unthreaded hole 
       56  first horizontal hole 
       58  first end 
       60  second vertical unthreaded hole 
       62  first horizontal hole 
       64  second end 
       66  vertical threaded hole 
       70  first unthreaded portion 
       72  first spring 
       74  second unthreaded portion 
       76  second spring 
       80  first horizontal threaded hole 
       82  second horizontal threaded hole 
       84  first tubular portion 
       86  first guard portion 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, milling machine  8  is shown equipped with chip deflector  10 . Chip deflector  10  is mounted on tenon  30  portion of ram  32  by means of mounting bracket  12 . First pivot arm  14  extends downward from mounting bracket  12  and then horizontally, supporting first plastic guard  16 . Mounting bracket  12  is attached to tenon  30  portion at a location that positions plastic guard  16  between the center line  31  of the spindle of milling machine  8  (and, hence, the point of operation) and the machine operator (not shown). 
     Referring to FIG. 2, a first preferred embodiment of chip deflector  10  is illustrated. Chip deflector  10  comprises mounting bracket  12 , first pivot arm  14  which supports first plastic guard  16  and second pivot arm  18  which supports second plastic guard  20 . Mounting bracket  12  is configured to provide mortise  22  portion of a dovetail joint. In the embodiment illustrated in FIG. 1, mounting bracket comprises two parts: first part  24  and second part  26 . The width of mortise  22  is adjustable by means of threaded rod  28  which is screwed into threaded holes in first part  24  and second part  26  of mounting bracket  12 . In an alternative embodiment, mounting bracket  12  is configured to provide a mortise having an adjustable width in accordance with the design illustrated in FIG. 3 of U.S. Pat. No. 5,103,541. 
     Mortise  22  portion of mounting bracket  12  slides onto tenon  30  portion of the dovetail slide that attaches ram  32  to the column of a vertical milling machine. When mounting bracket  12  is placed on tenon  30 , it is moved to a position that places center line  31  of the milling machine spindle between plastic guards  16  and  20  and vertical thumb screw  34  is tightened to secure mounting bracket  12  to ram  32 . Then, first vertical segment  36  of first pivot arm  14  is moved up or down to appropriately position first plastic guard  16 , and fit horizontal thumb screw  38  is tightened to secure first plastic guard  16  in position. Finally, second vertical segment  40  of second pivot arm  18  is moved up or down to appropriately position second plastic guard  20 , and second horizontal thumb screw  42  is tightened to secure second plastic guard  20  in position. In a preferred embodiment, the upper end of first pivot arm  14  is fitted with first rubber cap  15 , and the upper end of second pivot arm  18  is fitted with second rubber cap  19 . In a preferred embodiment, horizontal thumb screws  38  and  42  have nylon or brass tips. In a preferred embodiment, a product name, such as Batwing™ is written on the outside surface of first plastic guard  16 . 
     Referring to FIG. 3, a preferred embodiment of mounting bracket  12  is illustrated. Mounting bracket  12  is comprised of two parts that form mortise  22 . Mounting bracket  12  has first vertical unthreaded hole  56  and first horizontal hole  56  adjacent first end  58 , second vertical unthreaded hole  60  and second horizontal hole  62  adjacent second end  64  and first vertical threaded hole  66  below mortise  22 . Mounting bracket  12  is held in position on tenon  30  portion by a first vertical thumbscrew that is screwed into first vertical threaded hole  66  and that impinges on tenon  30 . First unthreaded portion  70  of first horizontal hole extends through first vertical unthreaded hole  54 , and first spring  72  is compressed in first unthreaded portion  70  to the extent that it is biased against first arm  14  and first arm  14  resists rotation and up and down movement. Second unthreaded portion  74  of second horizontal hole  62  extends through second vertical unthreaded hole  60  and second spring  76  is compressed in second unthreaded portion  74  to the extent that it is biased against second arm  18 , and second arms  18  resists rotation and up and down movement. In this embodiment, each of the parts of mounting bracket  12  has a horizontal threaded hole therein, the parts being held together by a threaded rod (not shown) that is screwed into first horizontal threaded hole  80  and second horizontal threaded hole  82 . In another preferred embodiment, mounting bracket  12  is constructed in a single piece. In this embodiment, the width of mortise  22  is not adjustable. 
     In a further preferred embodiment, each of the pivot arms comprises a horizontal portion, e.g., first horizontal portion  44  and second horizontal portion  46 , at least a portion of which is curved in a horizontal plane in the shape of a segment of a circle. In this embodiment, first plastic guard  16  is supported by first curved portion  48 , and second plastic guard  20  is supported by second curved portion  50 . 
     In another preferred embodiment, first plastic guard  16  and second plastic guard  20  each comprise a flexible plastic member having a longitudinal hole there through. In this embodiment, first pivot arm  14  and second pivot arm  18  are fitted through each hole. In an alternative embodiment, first pivot arm  14  and/or second pivot arm  18  support planar safety shields or guard panels similar to those disclosed in U.S. Pat. Nos. 4,043,701, 4,162,627, 4,543,021, 4,884,927 or 5,479,837. 
     Referring to FIG. 4, an alternative embodiment of chip deflector  10  is illustrated. In this embodiment, only one of the pivot arms (e.g., first pivot arm  14 ) supports a plastic guard (e.g., first plastic guard  16 ). The second pivot arm (e.g., second pivot arm  18 ) is a length of tubing that carries oil from source of oil  52 , e.g., a rubber or plastic tube carrying oil from a reservoir or pump (not shown), to the cutting surface. In this embodiment, plastic guard  16  has first tubular portion  84  and first guard portion  86  attached to first tubular portion  84 , plastic guard  16  being attached to first pivot arm  14  by horizontal portion  44  of first pivot arm  14  extending through first tubular portion  84 . 
     The best mode of the invention involves fabricating mounting bracket  12  from aluminum and pivot arms  14  and  18  from steel and first and second guards  16  and  20  from extruded thermoplastic. Conventional thumb screws, threaded rod or bolts and rubber tips are used. 
     Operation of the invention involves rotation of part  24  relative to part  26  until the width of mortice  22  is slightly wider than the width of tenon  30  portion. Then mounting bracket  12  is slipped on to tenon  30  and vertical thumb screw is tightened. Next, pivot arms  14  and  18  are rotated forward and toward the work area and secured in position with horizontal thumb screws  38  and  42 . When chip guard  10  is not required, pivot arms  14  and  18  are pivoted about vertical axes back away from the work area. 
     Many variations of the invention will occur to those skilled in the art. Some variations include a one-piece mounting bracket. Other variations call for a multiple-piece mounting bracket. All such variations are intended to be within the scope and spirit of the invention.