BACKGROUND OF THE INVENTION Field of the Invention The device of this invention resides in the area of shields that are positioned between a machine operator and the operative parts of a machine and more particularly relates to a machine safety guard and system using a plurality of such machine safety guards, each of which can be positioned, and selectively opened or closed, in front of operative parts of a machine.

Description of the Prior Art Industrial machinery can cause injuries to operators thereof if they are caught within the operative parts of the machinery or struck by elements emanating from such machinery. To reduce the chances of such injuries, the government through OSHA has instituted regulations which call for protective safety guards to cover certain operative parts of a machine to prevent a worker from being caught thereby or otherwise injured as the machine operates. These safety regulations provide for protective machine guards to be positioned in front of the operative parts of machinery, some utilizing machine power cut-off switches which function when such safety guards are removed from their positions in front of the operative parts of the machinery. Frequently

such safety guards can be in the form of a rigid sheet of plastic or glass which is fixed in front of the operative parts of the machinery. When such protective material is removed to gain access to the operating parts of the machinery, an electrical interlocking mechanism causes power to the machine to be turned off so that the machinery cannot be inadvertently operated when the safety guard is removed. Frequently machines require set-up for different jobs and this setting up period requires the operator to adjust elements of the machine to accomplish different functions during its operation such as using different materials or sizes of materials and/or different workpieces. It is often difficult and time-consuming to remove safety guards to gain access to the machine to change its set-up or otherwise adjust or repair such machinery, and such time-consuming procedures increase manufacturing costs.

Also well known in the prior art are light beam detectors which can sense when a light beam is interrupted for the purpose of shutting down the machinery. Such a system senses when one tries to reach towards a machine but is ineffective against projectiles flying away from the machinery which could injure a bystander.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved machine safety guard interconnected to a machine's power source which safety guard is fast and easy to operate and which gives an operator of a machine quick and safe access to the machine to change Its set-up or otherwise adjust or fix any operative parts of the machine when the safety guard is in its open mode position and the machinery is not operating.

It is a further object of this invention to provide a system of independently operated safety guard units which in one embodiment can be interconnected to one another and which individual units can be positioned around or on a machine at selected angles, heights, widths and distances from the machine to allow access to various operating parts of the machine at any desired time by the operator. Further, the safety guard units of this invention can be quickly and easily operated to disable the machine to allow access thereto to provide safety to the operator while set-up procedures or other maintenance operations are being performed on the machinery.

To achieve the goals of this invention a safety guard unit is provided which has a first and second side track member joined at their tops in one embodiment by an upper support member which is disposed perpendicularly to the side track members. Each of

the side track members can extend perpendicular to the floor, each track member having an inwardly facing channel defined on its inner side with such channels facing and aligned with one another. These side track members are disposed in front of the operative parts of the machine to be shielded by the safety guard. Within the upper support member can be disposed a rotatable reel having a flexible, transparent panel attached thereto along its length. This panel can be a sheet of clear, transparent PVC material or equivalent material. A reversible motor is provided to drive the reel and attached transparent panel to wind and unwind it to move the panel up and down within the channels between the first and second side track members. The flexible, transparent panel can be stopped at any position during its vertical travel, either all the way up, all the way down or at any intermediate position. The motor can be located on the upper support member or at any desired location on the safety guard unit and can be of the reversing type. The bottom of the guard can be weighted to pull it down against the force of the motor or other systems of pulleys or gears can be used to aid in the raising or lowering of the transparent panel. The transparent panel can be raised or lowered very quickly, and its bottom which is generally disposed horizontally can be flexible so that if it strikes the operator while in operation, it will

not cause harm because of the flexible nature of the clear plastic sheet material. A plurality of these safety guard units of this invention can be disposed around a large piece of equipment, each safety guard unit giving access to a different portion of the machinery to be operated. The safety guard units can have differing widths and heights and can have independent control switches for each safety guard unit so that each unit's transparent panel can be raised or lowered Independently of another's to gain access to a particular part of the machinery. The safety guard units, because they also tend to block sound, will cut down on the noise emanating from operating machinery.

The safety guard units can be mounted on the machinery itself or disposed adjacent to the machinery, either permanently affixed to the floor or disposed on wheels for portability to a desired location or position where the wheels can be locked.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a perspective view of a plurality of interlocked safety guard units affixed to the floof, such units surrounding an elongated piece of machinery.

Figure 2 illustrates a schematic block diagram of the power circuitry to operate the safety guard

unit of this invention.

Figure 3 illustrates a perspective view of a pair of safety guard units mounted on lockable wheels.

Figure 4 illustrates a cross-sectional view of an enlarged segment of a panel having a sound¬ proofing layer laminated to a plastic layer.

DESCRIPTION OF THE PREFERRED EMBODIMEN (S) Figure 1 illustrates the safety guard system 10 of this invention surrounding piece of machinery 44, shown in outline form. Safety guard system 10 is made up of a plurality of individual safety guard units, such as first safety guard unit 12, second safety guard unit 16, third safety guard unit 22 or fourth safety guard unit 24. These safety guard units are described with reference to one, but which description can be applied to each of the safety guard units. The safety guard units can be made of plastic, metal or other equivalent sturdy material in different widths and heights and positioned for use in various configurations to accommodate different shapes and sizes of machinery. Each safety guard unit, such as first safety guard unit 12, is comprised of first and second side track members 15 and 13 which are generally vertically disposed perpendicular to the floor. In one embodiment of the invention

the side track members can be joined at their tops by an upper support member 31 to form a free-standing unit. Disposed in upper support member 31 can be horizontally disposed reel 29. A panel of strong, flexible, transparent material 25 can be windably attached to reel 29, which panel travels between first and second side track members 15 and 13. In some embodiments the ends of reel 29 can be rotatably attached to the tops of first and second side track members 15 and 13. First and second side track members 15 and 13 have, respectively, a first and second channel defined therein facing inwardly such as second channel 14 visible in Figure 1. In one embodiment transparent panel 25 can ride up and down with one side thereof within second channel 14 and the other side thereof within the first channel, not shown in this view, of first safety guard unit 12. Transparent panel 25 can move up and down, winding and unwinding on reel 29 similar in fashion to the action of a window shade powered by reversible motor 20. Flexible, transparent panel 25 can be made of PVC plastic or other equivalent material and in one embodiment can be weighted at its bottom portion to aid in such panel's moving downward smoothly within the inwardly facing channels. In some embodiments the panel can be opaque. In yet other embodiments the panel can be made of sound-proof material, such as a panel made with flexible sound-reducing barrier sheets, such as EAR

composites from Cabot Safety Corporation or equivalent, either alone acting as a panel or laminated to another flexible sheet. Sound reduction is also possible merely by using two vinyl sheets with an air space defined between them. Figure 4 illustrates an enlarged cross-sectional view of a sound-proof barrier 66 with a flexible sheet 70 laminated to a flexible, sound-proof sheet 68 to form a panel. The panel can also be similar in structure to flexible metal rolling panels or grills or folding metal sectioas. Reversible motor 20 can, upon activation of switch 30 or equivalent means of activation, drive the transparent panel either upwards or downwards within the channels. When transparent panel 25 is in its downwardmost position, the safety guard unit protects the operator from the operating machinery located therebehind. As seen in Figure 1, third safety guard unit 22 has first side track member 19 and second side track member 19 which members are positioned perpendicularly to the floor and which, in some embodiments, can have floor mounts 26 which can be attachable to the floor, if desired. When in the downmost position, the panel can have an engageable interlock, such as female plug 72, which receives male plug 74 on the bottom of panel 78 to complete a circuit to machine motor 80 to allow current to be provided to such motor. When panel 78 rises, it pulls male plug 74 out of female plug 72

and breaks the circuit along line 82, thereby shutting off motor 80.

Figure 3 illustrates another embodiment of the safety guard units with each safety guard unit disposed on wheels, such as wheels 60 and 62, which can be locked after the guard units have been rolled into position. It is desirable to have a minimum of two adjacent guard units, such as guard units 52 and 54, attached to one another so that if one guard unit were to move or fall, it would electrically disconnect from the adjacent unit and cause the machinery to shut down. The safety guard units can also be attached directly to the machinery itself rather than being affixed to the floor or being disposed on lockable wheels. Safety guard units on wheels can be moved from place to place where needed. For example, if a particular machine is not being utilized, its safety guard units can be moved to another machine and used there, thereby providing a significant cost savings. The wheels can be locked once in position by locks 64 as seen in Figure 3.

In some embodiments the side track members of one safety guard unit can have attachment means along their outer sides to be attached to the outer side of another side track member of another safety guard unit. For example as seen in Figure 1, second side track member 21 and first side track member 17,

respectively, of fourth and third safety guard units 24 and 22 can be attached together. By bolting the bottoms of the side track members to the floor so that the side track members stand upright and perpendicular to the floor, the safety guard units can be positioned aligned in a straight line adjacent to one another or disposed at angles to one another such as seen between safety guard unit 18 and safety guard unit 16 so that they can be positioned around machinery of any shape. If the safety guard units are affixed to the floor, they do not need to be attached to one another. Each safety guard unit can have its own individual control unit, such as switch 30, and the safety guard unit's width, such as width 32 of third safety guard unit 22, and height can be of any desired dimensions. For example, as seen in Figure 1, the width of fourth safety guard unit 24 is wider than the width of any of the other safety guard units.

As seen in the schematic block diagram of Figure 2, switch 30 can be comprised of a control box 34 which can be positioned near a safety guard unit and can have an open button 36 which can be interconnected to reversible guard motor 42 to drive the motor to roll up the transparent panel 25 on reel 29 and also at the same time to cause electrical power 40 to machine 44 to be shut off. Also within control box 34 is close button 38 which will cause guard motor 42 to reverse direction and unwind transparent

panel 25, and once the transparent panel is fully unwound, will allow for reactivation of electrical power 40 to machine 44. In order for the operator to control when the machinery starts up, it is desirable that machinery start up be accomplished by a separate switch after the panel is in its closed position. When the panel is open, audible/visible alarm 50, also seen in Figure 1 as light 48 with audible alarm, can be activated to warn people that the operative parts of the machinery are no longer guarded by the panel. A series of electrical or optical switches can be located at the bottom of each safety guard unit to act as a further safety interlock, which switches can be activated by the transparent panel being in its most downward, closed position in order for electrical power to the machinery to be restored. Also, electrical connections can be provided between adjacent safety guard units such as seen in Figure 3. Thus if, for example, safety guard unit 54 should fall, its electrical connection with safety guard unit 52 would separate, causing the machinery to shut down.

An important feature of this invention is providing a flexible, transparent panel of each safety guard unit which can be rolled up and unwound very quickly, rolling it up when it is desired to gain access to the machinery behind it and deactivating the machinery in such situations. First safety

guard unit 12 is shown with its transparent panel 25 in an up position so that access can be had to the machinery therebehind while third safety guard unit 22 is shown with its transparent panel in its most downward position, ready to protect the operator from operative parts of the machinery therebehind. It is a further object of this invention that a plurality of such safety guard units be positioned around the operative parts of a machine in a configuration of differing heights and widths and in differing angular configurations, as desired, to conform to the shape and dimensions of various kinds of machinery. Such units can be adjacent to one another as shown in Figure 1 or can be separated a distance from one another depending on the location of the operative parts of the machine.

Although the present invention has been described with reference to particular embodiments, it will be apparent to those skilled in the art that variations and modifications can be substituted therefor without departing from the principles and spirit of the invention.