US2059324A - Safety device - Google Patents

Description

Nov. 3, 1936. J. T. EMSLIE I SAFETY DEVICE Filed Feb. 12 1935 2 Sheets-Sheet l I. l' "I iii-" M. 14m ATTORNEY Nov. 3, 1936. J. T. EMSLIE I 2,059,324

SAFETY DEVICE Tiled Feb. 12, 1935 2 Sheets-Sheet 2 INVENTOR John T. [maize BY MA 1 m ATTORN EY Patented Nov. 3, 1936 SAFETY nnvrca John '1. Emslie, Arlington, N. J., assignor, by

mesne assignments, to E. I. du Pont de Nemours 8; Company, Wilmington, Deb, a corporation of Delaware Application February 12, 1935, Serial No. 6,185 7 Claims. (01. 192- 133) This invention relates to a safety device for rolls and, more particularly, to a safety device for actuating the tripping means, such as a clutch throw-out or other means, for stopping a set of mixing rolls instantly.

In the plastics art particularly, the use of mixing rolls, sometimes referred to as colloid rolls, is general for working masses of rubber, cellu lose derivatives, resins, and such plastics. These rolls conventionally comprise a frame, a pair of rolls mounted on said frame with-their axes parallel and in the same horizontal plane, and means for driving said rolls. In using these rolls the operator is required to handle the mass being worked on the rolls. This can be done with safety as long as the operator keeps his hands away from the bite of the rolls but experience has proved .that operators grow careless and every so often an operatorgets his hand caught in the bite of the rolls and is frightfully injured.

The industry has long recognized this danger to the operator and these rolls are today generally provided with a cable, chain, or bar, positioned well above the bite of the rolls and connected to some conventional tripping means, such as a clutch throw-out, for stopping the rolls. stantly stopped by the operator, if one'hand should get caught in the rolls,.by reaching up with the other hand and pulling the cable. In this manner the degree of severity of the injury to the operator can usually be lessened except in the rare instance where both hands are caught in the rolls but the actual occurrence of the accident is no more prevented than before. There is nothing to prevent the operator from getting his hand in the bite of the moving rolls.

An object of this invention is to provide, in combination with a set of mixing rolls, a safety device that will automatically actuate any conventional tripping means for stopping the rolls instantly if the operator makes any dangerous movement toward the bite of the rolls before any injury can be done to the operator. A further object is to provide a safety device that will not interfere with the normal, safe operation of the rolls. A further object is to provide a safety device that will be actuated without conscious effort of the operator. A still further object is to provide a device which can be made to pro-- side With such a device the rolls can be inbetween the rolls.

the rolls, a guard rod carried by said rigid member in a position parallel to said rolls and norperspective view of a conventional set of mixing rolls with a safety device according to thepresent invention mounted thereon;

Fig. 2 is an enlarged front elevation of the safety device per se, parts being broken away for purposes of illustration;

Fig. 3 is aside elevation of the safety device from the position of the'line 3-44 in Fig. 2;

Fig. 4 is a detail section on the line t-t of Fig. 2.

In the drawingslike reference numerals refer to like parts throughout.

Referring to Fig. 1 of the drawings, a conventional set of mixing rolls is illustrated comprising the rolls I, 2 mounted in the frame 3 with the associated housing t in which is located the means for driving the rolls l, 2. The driving means may comprise a driving shaft common to several sets of rolls or any other conventional source of ,driving power and is, of course, provided with some tripping means, as a clutch throwout. The driving means and tripping means have long been used with mixing rolls and, for the sake of simplicity, are not illustrated as they are entirely familiar with those skilled in this art. To, understand the present invention, it is sufiicient to know that the tripping means is actuated by moving the chain 5 upward.

The assembly so far described typically illustrates prior art mixing rolls except that the chain 5 would be run up over a pulley, or the like, and down a convenient distance for the operator to reach in order to stop the rolls in an emergency.

The present invention comprises a pair of vertical frame members l I, I2 mounted on the frame 3, one at each end of the rolls 1, 2 and centrally member if by means of the stud it having a flangedstop it, said stud it being held in fixed position by means of set screw it, is the vertical link it. This link is adapted to swing freely with the stud it as its axis. Link it is triangular inshape (see Fig. 3) and is provided at its base in each corner with a boss provided with a hole through which passes a. bolt adapted to carry the guard assembly. Since the guard assembly for (iii the front and back of the set of rolls is identical, it will only be described with respect to the front of the apparatus as viewed in Fig. 1.

Through the hole in the boss "SA on the front side of link I6, as viewed in Figs. 1 and 2 or to the right in Fig. 3, passes the bolt H on which is pivotally carried one end of the rigid arm I8.

- The surfaces of arm l8 and boss |6A of link I6 bearing against each other are serrated as indicated at I9 (Fig. 2) and the bolt carries the nut 20 to lock arm l8 and link I6 in fixed position with respect to each other. By loosening-the nut 20 the arm |8 may be pivoted with the bolt H as its axis and its angle with link I6 fixed by tightening up the nut 20. The other end of arm I8 is provided with the elongated interior slot 2| (see Fig. 3). A bolt 22 passes through'bearings in clamp members 23 and 24 which surround the arm l8, and through the slot 2|, and is screwed into the interiorily threaded block 25. The surfaces of clamp member and block 25 bearing against each other are serrated, as indicated at 26, to hold them in fixed position with respect to each other when the bolt 22 is tightened up. Tightening of bolt 22 also holds clamp members 23 and 24 in fixed position along the arm 18. By loosening bolt 22 the position of clamp members 23 and 24 along the slot 2| of arm l8 may be adjusted as well as the angular relation of block 25 with respect to clamp member 24.

The block 25 is drilled to receive one end of the guard rod 28 which is held fixed by set screw 29. Also block 25 is drilled to receive one end of a second guard rod 36 which is held fixed by set screw 3|.

As clearly illustrated in Fig. 2 there is a vertical link 35, similar to vertical link I 6, pivotally swung from the vertical frame member l2, the mounting of vertical link 35 and parts associated therewith being identical with those illustrated and described with reference to vertical link l6.

From the above description, it will be seen that there is provided pivoted means for holding the guard rods 28 and 30 in'a position parallel to and above roll 2. By manipulation of bolt l1 and nut 20, bolt 22, and set screws 29 and 3| in connection with vertical link l6, and similar parts in connection with vertical link 35, the position of both guard rods 28 and 36 may be adjusted. Guard rod 28 is adjusted so that it will extend parallel to and above roll 2 in a. position so that the operator will be able to work freely around the mixing rolls with the plastic being processed but, if he moves his hands dangerously near the bite of the rolls, his arms will inevitably strike the rod 28. The second guard rod 30 is not necessary but is useful in preventing the operator from reaching over rod 28 dangerously close to the bite of the rolls. As illustrated in Fig. 1, an identical assembly is preferably mounted on vertical links l6 and 35 for protecting the back side of the set of rolls. This is not absolutely necessary and may be eliminated if desired. A weight for counterbalancing the front assembly would then be used.

It will be understood that the guard assembly is pivotally mounted above and at each end of the rolls, the axes of the pivots being parallel to the axes of the rolls, and is normally in a position at the bottom of its are. If the operators body strikes the guard rods the assembly will naturally be swung through an are out of its normal position and it is this movement that is employed to actuate the tripping device through the chain 5.

To accomplish the actuation of the tripping device the vertical link 35 is provided intermediate its length with the boss 40 on the side adjacent the frame member |2. Mounted on this boss 40 by bolts 4| is the bracket member 42 having a horizontal surface 43 of triangular shape with its base adjacent the boss 40. This member 42 is made with the upstanding flange 44 along the'periphery of its horizontal surface 43. To this flange is secured by screws 45 a. cam track 46 of wear resisting metal. The frame member I2 is provided with a bearing section 41, through which passes the horizontal slide link 48. One end of this link carries a block 56 having a rectangular cut out portion in which is mounted the vertical pin 5|. A roller 52 is rotatably mounted on the pin 5| and is adapted to bear against the cam track 46. The opposite end of the slide link 48 is connected by link 53 to one end of the L- shaped lever 54 pivotally mounted on the housing 4 (Fig. 1). The other end of lever 54 is attached to the chain 5 operating the tripping device.

When the guard assembly is in normal position, vertical link 35 is in the position shown in Fig. 4 and slide link 48 is in its extreme 'right position which holds the chain 5 taut but does not actuate the tripping means. When the guard assembly is moved by the operator in either direction, link 35 swings on its pivot and moves the cam track 46 and its associated parts either up or down viewing Fig. 4. Either movement, due to the roller 52 bearing on the cam track 46, causes the slide link 48 to move to the left, pivoting the lever 54 and consequently pulling on chain 5 which actuates the tripping machine.

Cross bars 60 carried in the brackets 6| mounted on the frame work 3 are provided for the operator to grasp with one hand while working under the rolls with the other.

While the safety device according to the pres ent invention has been described with respect to the specific embodiment illustrated in the drawings, it will be understood that the invention is not to be limited to this specific embodiment since it broadly comprises a guard rod carried by a frame pivotally mounted above the rolls, the normal position of the guard rod being substantially vertically above one of the rolls a distance such that the arms of the operator of the rolls will strike it and move it through an arc around the pivot of the frame if he makes a dangerous movement toward the bite of the rolls, and means whereby the movement of the guard rod causes the tripping means for throwing the driving shaft or equivalent means for driving the rolls out of gear, to be actuated.

Obviously, the specific means disclosed for translating the circular movement of the vertical links l6 and 35 into a lateral movement for actuating the chain 5 connected to the tripping means need not necessarily be employed, any

other equivalent mechanical structure coming within the spirit of this invention.

The present invention provides a substantially infallible device for preventing an operator of mixing rolls from getting his hand caught in the bite of the rolls. Any dangerous move which he may make toward the bite of the rolls will automatically stop the rolls without any conscious act on the part of the operator. This device prevents the accident entirely, rather than merely tending to reduce the extent of injury, as did the equally well from the back or the front of the ,rolls. A further advantage of this device is that the guard rods cover the full length of the rolls and thereby protect the complete operating zone.

As will be understood by those skilled in the art, the safety device of the present invention is not only adapted to protect operators of mixing rolls which are positioned horizontally, such as are commonly employed in the plastics art, but is equally well adapted to protect the operating zone around vertically disposed adjacent cooperating rolls where the axes of the rolls are parallel and in the same vertical plane. The safety device is broadly applicable for the protection of sets of rolls in the plastics industry, in the paper industry, and the various other fields where an operator must work around cooperating rolls of the general type herein described.

It should benoted that the movement of the guard rod may cause the opening or closing of an electrical circuit to thereby actuate the tripping means for the rolls, if desired, instead of moving a purely mechanical connecting means as illustrated in the drawings. Y

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. In combination with a set of mixing rolls comprising a frame, a pair of rolls mounted on said frame with their axes parallel and in the same horizontal plane, driving means for said,

rolls, and tripping means for throwing said driving means out of gear, a safety device comprising a supplemental frame member mounted-on said frame and extending above said rolls, rigid means pivotally mounted on said supplemental frame member at a point above said rolls and with the axis of said pivot parallel to said rolls, a guard rod carried by said rigid means in a position parallel to said rolls and normally; substantially vertically above one of said rolls a distance such that the arms of the operator of the rolls will strike said guard rod and move it through an are around dangerous movement toward. the bite of said rolls from the side of said set of rolls over which said guard rod is positioned, and means connecting said rigid means to said tripping means wherei by said tripping means is actuated by movement of the guard rod from its normal position.

2. A safety device'asset forth in claim 1 wherein said rigid means carries a second guard rod above the other of said rolls in the same relative position as said first guard rod.

3. In combination with a set of mixingrolls comprising a frame, a pair of rolls mounted on said frame with their axes parallel and in the same horizontal plane, means for driving said rolls, and tripping means for throwing said driving means out of gear, a safety device comprising a pair of supplemental frame members mounted on said frame centrally between said rolls and extending above said rolls at each end thereof, a pair of-rigid members pivotally mounted on said supplemental frame members, the axes of the pivots of said rigid members being parallel to the rolls. a guard rod normally carried. by said rigid members in a position parallel to saidrolls and substantially vertically above one of said rolls a distance such that the arms of the operator of the rolls will strike said rod and move it through an arc around the axes of the pivots on the rigid members if he makes a dangerous movement toward the bite of said rolls from the side of said set of rolls over which said guard rod is pivoted, and means connecting one of said pair of rigid members to said tripping means whereby said tripping means is actuated by movement of the guard rod from its normal position.

p 4. A device as set forth in claim 3 wherein said pair of rigid members carries a second guard rod above the other of said rolls in the same relative position as said first guard rod.

5. In combination with a set of mixing rolls comprising a frame, a pair of rolls mounted on said frame with their axes parallel and in the same horizontal plane, means for driving said rolls, a tripping means for throwing said driving means out of gear, a safety device comprising two upright frame members mounted on said frame centrally between said rolls at each end thereof and extending above said rolls, apair of links position substantially horizontally and at right angles to the rolls, a guard rod carried at each end by said second pair of links and normally positioned parallel to said rolls and substantially vertically above one of said rolls a distance such that the arms of the operator of the rolls will strike said guard rod and move it and the links associated with it in an are around the axes of the pivots of said first pair of links if 'he makes a dangerous movement toward thebite of the rolls from the side of said set of rolls over which said guard rod is pivoted, and means connecting one of said first pair of links to said tripping means whereby said tripping means is actuated by movement of the guard rod from its normal position.

6. A safety device as set forth in claim 5 wherein a second guard rod is carried by an associated pair the pivot of said rigid means if he makes ma of links rigidly mounted on said first pair of links, above the other of said rolls in the same relative position as said first guard rod.

'7. In combination-with a set of rolls comprising a frame, a pair of adjacent cooperating rolls mounted on said frame with their axes parallel, driving means for said rolls, and tripping means for throwing said driving means out of gear, a safety device comprising a supplemental frame member mounted on said frame and extending above said rolls, rigid means pivotally mounted on said supplemental frame member at a point above said rolls and with the axis of said pivot parallel to said rolls, a guard rod carried by said rigid JOHN WSLE.

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