US 3541950 A
Description (OCR text may contain errors)
United States Patent 192/129, 130, l3l;74/612,613,614,615; 83/68, 397; 18/(Safety Digest) References Cited UNITED STATES PATENTS Stacy Primary ExaminerBilly J. Wilhite Attorney-Wilson & Geppert ABSTRACT: A safety device for a platen press to prevent injury to the operator thereof where the safety device must be deliberately actuated to allow operation of the press. The device includes a pivotally mounted safety block or bar normally biased so that the bar is in the path of travel of a press platen to halt downward movement thereof, and a press trip lever secured to the safety bar and having a switch actuator to operate the switch causing reciprocation of the press platen. The trip lever is depressed by the operator to pivot the safety bar out of the path of the platen and simultaneously actuates the press operating switch.
Patented Nov. 24, 1970 3,541,950
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PRESS SAFETY DEVICE The present invention relates to a novel safety device and more particularly to a safety block or bar utilized in a platen press to prevent accidental movement of the reciprocating press platen and thus prevent injury to the press operator.
Injury to workmen in manufacturing plants and factories causes untold loss of man-hours and profit to the business and loss of wages to the worker, and the possibility of partial or total disability for the worker. Therefore, safety programs have been instituted in factories and plants to reduce the number and extent of injuries. Such programs include safety procedures to be followed and safety devices to be used on various machines. Platen presses which operate under high energy for stamping, forming or trimming'operations are a cause of injury to the hands and/or arms of the operator if'the area between the platens is not clear prior to actuation ofthe press. The present invention provides a safety device for platen presses and the like with a high degree of safety.
Among the objects of the present invention is the provision of a safety device for platen presses having a higher degree of safety than other devices presently known. This device includes a pivotally mounted safety block or bar that is normally biased into the path of the movable press platen permitting only limited movement of the platen unless the safety bar is deliberately pivoted out of the path or line of travel of the platen. 1
Another object of the present invention is the provision of a safety device for a platen press having a pivotally mounted safety bar and a press -trip lever secured to said bar and extending outward from the press which must be depressed by the press operator to pivot the safety bar to inoperative position. By placing one or both hands on the lever, the operator has his or her hand out of the die area of the press.
A further object ofthe present invention is the provision of a platen press safety device where the press trip lever secured to the safety bar actuates the operating switch for the press platen. The switch is positioned below the forward portion of the lever and is actuated by a depending projection on the lever.
Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.
In the drawings:
FlG. l'is a perspective view of a platen press having the novel safety device of the present invention installed thereon.
H6. 2 is a horizontal cross-sectional view taken on the line 2-2 ofFlG. 1.
FIG. 3 is a partial side elevational view of the press with the safety device thereon.
P16. 4 is a partial front elevational view of the press showing the safety device.
Referring more particularly to the disclosure in the drawings wherein is shown an illustrative embodiment of the present invention, HO. 1 discloses a platen press for use in stamping, trimming or other forming operations of metal or like material. The press 10 includes a lower stationary platen 11 and an upper reciprocable platen 12 movable on guide rods 13 positioned adjacent the corners of the platens. The upper platen 12 is actuated by suitable means such as a hydraulic piston and cylinder or a toggle linkage; however, the means of actuation is well known and is not more specifically disclosed for the present invention.
The lower press platen 11 has a die plate 14 secured thereto by clamping members 15 with the plate carrying a suitable stamping, trimming or other forming die 16 thereon. Also, the
upper platen 12 has a die plate 17 secured thereon and carrying an upper stamping, trimming or other forming die 18. The dies 16 and 18 are adapted to form to a desired configuration a sheet of metal placed therebetween during a cycle of operation of the upper platen 12.
A press safety device 19 is mounted on the. lower press platen adjacent a front corner thereof having a base 21 secured to the platen by suitable fastening means, such as the bolts or cap screws 22. The base 21 is secured to the lower platen 11 directly below the corner 23 of the upper platen 12. The base 21 is a generally U-shaped or bifurcated member having a pair of spacedparallel upwardly extending arms 24,24 (FIG. 4) each having a horizontally aligned opening 25 therethrough. Each opening 25 (FIG. 3) receives a bushing 26 secured therein, and a pivot pin 27 has its opposite ends received in the bushings 26,26. Suitable oilers (not shown) can be located in the arms 24,24 to lubricate the pivot pin 27 in the bearings 26,26.
Mounted on the pivot pin and extending upward from between the arms 24,24 is an elongated safety bar or stop block 28 having its upper end 29 positioned slightly below and vertically aligned with the corner 23 of the upper platen 12. The bar 28 is cut away on the inner surface for approximately the upper half, as at 31, to provide sufficient clearance for movement of the press platen 12 during a forming operation.
An adapter plate 32 has a slot 33 therein to receive the safety bar 28 and is secured to the bar at a location spaced above the base 21 as by welding at 34. The plate 32 extends laterally inward of the bar 28, shown to the left side of the bar in FIG. 4, and a press trip lever or actuator 35 has one end 36 secured to the left hand end of the plate 32 by suitable securing means, such as cap screws 37. The actuator 35 extends forwardly of the base 21 to a vertical or depending portion 38 and an actuating end or handle 39 is offset downwardly from the other end 36.
The upper horizontal portion or end 36 has a threaded stud or set screw 41 extending therethrough and a lock nut 42 retains the stud 41 in an adjusted position in the portion 36. An L-shaped bracket 43 mounted on the edge of the lower platen 11 supports a switch housing 44 having an upper open end covered by a switch cap 45 suitable secured to the housing 44. A vertically movable switch member 46 is positioned in the housing 44 adapted to be engaged by the lower end 48 of the stud 41 extending into the housing through an opening 47 in the cap 45. A cable 49 connects the switch member 46 with the control mechanism actuating the upper press platen 12.
The adapted plate 32 is also provided with a pair of depending guide pins 51 secured thereto at either side of and slightly forwardly of the safety bar 28. A pair of compression springs 52 are provided with each spring having one end 53 received in a blind opening formed on one of the arms 24 and the opposite end encompassing one of the depending guide pins 51.
The springs 52,52 bias the plate 32 and the safety bar 28 to a position where the end 29 of the safety bar is vertically aligned below the corner 23 of the upper platen 12. g
In operation, the safety device 19 is shown in its normal position in FIGS. 1, 2 and 4, and in solid lines in FIG. 3. If the press is accidentally or inadvertently actuated or tripped with the safety bar 28 biased to 'its normal position, the corner 23 of the platen 12 will, upon slight downward movement, engage the upper end 29 of the bar and could in no way lower further to close and injure the hands of the operator who may have his or her hands in the die area.
To operate the press 10, the operator, having removed his or her hands from the die area, places one or both hands on and depresses the handle or end 39 of the lever or actuator 35 which pivots the lever, adapter plate 32 andsafety bar 28 about the axis of the pivot pin 27 to draw the upper end 29 of the bar 28 forwardly out of the path of the press platen 12 as seen in dotted lines in FIG. 3. simultaneously, movement of the lever 35 causes downward movement of the stud 41 with the lower end 48 entering the opening 47 in the cap 45 to depress and close the switch member 46 and initiate a reciprocating cycle of the platen 12.
Upon release of the lever 35, the springs 52 expand to bias the bar 28 and rotate the pivot pin 26 to move the end 29 back to its normal stop position once the platen l2'has returned to inactive position. Then the operator can work in the die area preparatory to another cycle of the platen 12. While the safety device has been shown and described as being advantageously applicable to platen presses, it is not my desire or intent to unnecessarily limit the scope or the utility of the improved features by virtue of this illustrative embodiment.
I claim: 1. A safety device for a machine having a movable member reciprocating toward and away from a stationary member, comprising a pivotally mounted safety block normally biased into the path of movement of the movable member, a base secured to the stationary member and bifurcated to receive the safety block therein, a pivot pin extending through the bifurcated portion and the lower end of the safety block a manuallyactuated trip lever operatively connected to said safety block to pivot the block out of the path of the movable member, and a switch actuating said movable member adapted to be operated bymovement of said trip lever. I
2. A safety device as set forth in claim 1. including a bushing received in each bifurcation and horizontally aligned to receive the ends of said pivot pin.
3. A safety device for a machine having a movable member reciprocating toward and away from a stationary member, comprising a pivotally mounted safety block normally biased into the path of movement of the movable member. an adapter plate secured to said safety block spaced above the pivotal mounting therefor and extending laterally thereof, a manually-actuated trip lever secured to said lateral extension of the adapter plate to pivot the safety block out of the path of the movable member, and a switch actuating said movable member adapted to be operated by movement of said trip lever.
4. A safety device as set forth in claim 3, including a base secured to said stationary member and bifurcated to receive and pivotally mount the safety block therein, compression springs received in the bifurcations ofthe base, and depending pins on the adapter plate receiving the free ends of said springs.
5. A safety device as set forth in claim 4, in which said springs are positioned forwardly of the pivotal mounting for the safety block and bias said safety block into a position blocking the path of said movable member.
6. A safety device for a machine having a movable member reciprocating toward and away from a stationary member. comprising a pivotally mounted safety block normally biased into the path of movement of the movable member, a manually-actuated trip lever operatively connected to said safety block to pivot the block out of the path of the movable member, a switch actuating said movable member adapted to be operated by movement of said trip lever, a housing for said switch mounted on the stationary member and positioning said switch directly below said trip lever, and a depending stud on said trip lever adapted to depress and actuate said switch.
7. A safety device as set forth in claim 6 in which said stud is adjustably threaded in said trip lever, a lock nut on said stud. and a switch cap on the housing having a central opening aligned with and receiving the depending end ofthe stud.
8. A safety device for a machine having a mmable member reciprocating toward and away from a stationary member, comprising a pivotally mounted safety block normally biased into the path of movement of the movable member, a manually-actuated trip lever operatively connected to said safety block to pivot the block out of the path of the movable member, and a switch actuating said movable member adapted to be operated by movement of said trip lever, said safety block being an elongated pivotally mounted bar having a free end located adjacent the normal open position of said movable member, said bar being reduced along its length from the free end to allow movement of the movable member when the bar is pivoted to inactive position.