Patent GB-421194-A (GB)
Title: Improvements in guards for machines
IPC: F16P3/04
Filed: 1933-06-21
Abstract: 421,194. Machinery guards. BAILEY, J., c /o Manifoldia, Ltd., Bromford Lane, West Bromwich. June 21, 1933, Nos. 17746 and 25672. [Class 80 (iv)] A guard device for guillotines, presses, platen printing machines, &c., comprises a vertically movable primary guard 12, 13, a secondary guard 23 movable towards the operator and away from the space to be guarded, and means for operating the secondary guard in the event of the machine being set in operation with the primary guard in its inoperative position. The primary guard comprises a number of rods 12 loosely mounted in a cross bar 13 slidable on guide rods 14a and released so as to fall under the action of gravity by a catch lever 17 mounted on a shaft 18 turned by a handle 19. The rods 12 slide through holes in a fixed bar 14 and have enlarged heads 15 to prevent them passing through the holes in the bar 13. The rods are thus capable of yielding to accommodate work passing under the guard. The secondary guard has a cross bar 23 joined to side members 24 pivoted to spaced links 25, 26 in turn pivoted to brackets 29 on the machine frame and is operated by the machine crank or one of the operating levers of the knife 11 or other tool, through a link 40, a crank 39, a spindle 36, a cam 37, a lever 32, a link 31, and a crank 30 connected to one of the pivots 28 of the links 25, 26. The secondary guard is rendered inoperative when the primary guard has been lowered by moving the cam 37 along its spindle against springs 38 out of the path of the lever 32. This is done through a collar 41, a striker 42, a link 43, a crank 44, and a shaft 45, on which is a crank connected by a link to the primary guard releasing lever 17. The shaft 45 also carries a notched arm 48 which engages a pin 50 on the lever 17 to hold it in guard-releasing position, the arm being moved clear of the pin by a rod 51 when the primary guard is raised by a handle (not shown). The shaft 18 carries a cam 54 which engages a pin on a catch 52 to release the catch when the handle 19 is operated to release the primary guard. The cam 37 is adjustable by a pin-and-slot arrangement and carries on its rearward face a cam part 61, Fig. 2, which engages a fixed pin 62, Fig. 1, to move the cam 37 out of the path of the lever 32 when the secondary guard has been moved to the operative position, and hence to move the lever 17 and so release the primary guard. The movement of the bar 23 may be adjusted by varying the positions of the link pivots on the machine frame or on the side members 24. Another form of secondary guard comprises a horizontally moving bar connected by links in lazy-tong formation to the machine frame. According to the first Provisional Specification a secondary guard of the latter form is moved to its operative position by a cam or projection on one of the knife operating levers which engages a pivoted pawl on a horizontally sliding bar connected by a system of links and levers to one of the links of the secondary guard. The primary guard is connected to the pivoted pawl by a chain so that the pawl is moved out of the path of the cam or projection on the knife-operating lever when the primary guard is moved to its operative position. The secondary guard is retained in its operative position by a pivoted catch engaging a stop on the sliding bar and moved out of engagement therewith by the continued movement of the operating cam. According to the second Provisional Specification, the secondary guard shown in Figs. 1, 2, may be used alone, in which case the guard is permanently connected to the knife-operating means and actuated at each working stroke, or the handle 19 is arranged on the opposite side of the machine to the starting control so that both hands must be used to prevent the guard operating. The handle 19 is biassed by weights in preference to springs.