Safety locking device

#1. Field of the Invention

#The present invention relates generally to safety devices for locking moving parts of heavy machinery against accidental movement. More particularly, the invention concerns a safety locking device for positively preventing rotation of a chain-carrying sprocket wheel of the character typically found in large presses and die cutting machines.

#2. Discussion of the Invention

#FIG. 1 is a fragmentary, generally perspective view of the safety locking device of the present invention mounted proximate a sprocket wheel of a large die cutting and creasing press of the character used in the cardboard and corrugated and chipboard product industries.

#FIG. 2 is a generally perspective, exploded view of the safety locking device of the invention.

#FIG. 3 is a side-elevational, partially schematic view of the safety locking device depicted as being interconnected with appropriate solenoid control valves and an electrical control panel for operation of the pneumatic cylinder assembly unit of the device.

#Referring to the drawings and particularly to FIGS. 1 and 2, one form of the platen press safety lock device of the present invention is there illustrated and generally designated by the numeral 12. The safety lock, the operating components of which are best seen in FIG. 2, is specially designed for use with large die cutting machines and platen presses of the character widely used in the cardboard and corrugated and chipboard product industries. Typically, these large machines, a portion of one of which is illustrated in FIG. 1, comprise a basic frame 14 to which sprocket wheels 16 and 16a are rotatably connected by means of a transversely extending axle assembly 17. Each of the sprocket wheels 16 and 16a include a plurality of circumferentially spaced teeth 18 which are engagable by the links of endless chains. One of these chains, designated in FIG. 1 by the numeral 20 is trained about sprocket wheel 16 in the manner illustrated in FIG. 1 and is also typically entrained about a plurality of driving and idler sprocket wheels of the character illustrated and described in U. S. Pat. No. 3,577,834 issued to Lang. This latter patent describes in greater detail a platen press of the type with which the safety lock of the present invention can be used. Because of the importance of U.S. Pat. No. 3,577,834 to a complete understanding of the present invention, U.S. Pat. No. 3,577,834 is hereby incorporated by reference as though fully set forth herein.

#As illustrated in the drawings and particularly in FIGS. 1, 7 and 8, the safety lock of the present invention functions to prevent rotation of the sprocket wheel 16 when the safety lock is moved into the sprocket wheel locking position illustrated in FIG. 7. Referring particularly to FIGS. 2, 3, and 7, the safety lock device of the form of the invention there illustrated comprises means defining a sprocket wheel receiving opening or channel, which is here provided in the form of a locking block 22 that is constructed from steel or other suitable metal (FIGS. 2 and 3). As best seen in FIG. 2, locking block 22 includes first and second integrally formed, downwardly depending, spaced-apart wall portions 24 and 26 which cooperate to define therebetween a sprocket-wheel receiving channel 29.

#Connected to locking block 22 and extending inward there-from, that is away from sprocket wheel 16, is a pair of spaced-apart guide shafts 28 which guide movement of a connector means, which, in a manner presently to be described, connects the actuating means of the invention with the sprocket-locking members. The connector means here comprises a connector or shuttle, plate 30 which is controllably movable toward and away from the rear face 22a of the locking block 22 by the actuating means of the invention. Affixed to plate 30 and extending outwardly therefrom in a direction toward sprocket wheel 16, is a pair of spaced-apart, rod-like locking members 32. The outboard end portions 32a of locking members 32 are closely receivable within aligned bores 34 and 36 provided in walls 24 and 26 of locking block 22. As indicated in FIGS. 7 and 8, when members 32 are in a locking position, they extend through bores 34, through sprocket-receiving opening, or channel 29, and into bores 36 which are precisely aligned with bores 34. The inboard end portions 32b of members 32 are receivable in bores 33 provided in shuttle plate 30 and are secured therewithin by set screws 35 (FIG. 1). When locking pins 32 are in the sprocket wheel locking position shown in FIG. 7 and 8, they extend into channel 29 and into the openings 19a and 19b which are located between a pair of adjacent sprocket-wheel teeth 18a and 18b (FIG. 8) of sprocket wheel 16.