Patent GB-191411918-A (GB)
Title: Improvements in Presses.
Inventor: ALVORD ELISHA HENRY
IPC: B30B9/04
Filed: 1914-05-14
Granted: 1915-05-14
Abstract: 11,918. Alvord, E. H. May 14. Presses, governing and controlling; relief-devices for; ram - retracting devices; working valves.- A piston press comprises cylindrical members 4, 5, Fig. 1, which serve respectively as pressure and power chamber, a piston 3, and movable heads 1, 2 attached to rods 1<1> which slide through guide boxes in the members 4, 5. The material to be pressed is supplied from a hopper 41 through a valve 40 by means of a pressing - device 42 with perforated plate sections or wings. The power system for a p p l y i n g pressure to the piston 3 comprises a valve 6, a pressure regulator 7, and an intensifier 8. With the valve 6 in the position shown, fluid at normal pressure enters the power chamber through the pipe 5" fitted with a non-return valve, and is supplied also to the high-pressure end of the intensifier cylinder 8, the low-pressure end being open through a pipe 7<a> to the waste pipe. When the valve 6 moves to its lower position, fluid under normal pressure enters the pipe 7<a> and the low-pressure end of the cylinder 8, giving a supply at increased pressure to the power chamber through the pipe 8<1>. After compression, an auxiliary piston 27 is moved forward to open an exhaust valve 2<1> and, by means of a collar 21, to push forward together the head 2, the piston 3, the pressed cake, and the head 1. From the forward position, the cake is discharged by means of a vertically-moving ejecting-device 44. A catch 3<1> enables the piston 27 to withdraw the piston 3 with the heads 1, 2 when the apparatus is being arranged for recharging. The valve 6, a valve 29 which regulates the supply of fluid to operate the piston 27, the valve 40, the presser 42, and the ejector 44 are all operated by levers pivoted on a shaft 50 and engaged at the desired intervals by cam-controlled catches on a carrier 52 which is continuously oscillated on the shaft 50 by means of a connecting-rod 56 and spur gearing 55 from the shaft 57. The carrier, Figs. 9 and 10, comprises a frame 54 in which the camshafts 59, 60 are mounted, and a slide 17 carrying pawls 14<a>, 15<a> which operate ratchet-wheels 14 on the cam-shafts, the slide being connected by a link 17<1> to an eccentric pin on the bracket 51. In order that the time of application nf increased pressure in the power chamber and its duration may be varied, one of the ratchet-wheels 14 is incomplete, the motion being continued by a slowmotion ratchet-ring 33<c>, Fig. 9, with adjustable lost-motion between it and the wheel 18 which is fixed to the wheels 14. The ring 33<c> is carried by a single arm 33<a> on a collar 33<b> and is secured by a pin 35 to the sleeve 34<b> on which is mounted a rim 34 by means of a single arm 34<a>. On the rim 34 is carried a pawl 15<h> which is adjusted in relation to the arm 34<a> by loosening a screw 19<a> and turning the ring 19. The pawl 15<h> works over the wheel 18, but is held by a spring out of engagement therewith. The wheel 18 is also connected with the ring 33<c> by a pin 18<1> which projects between the arms 33<a>, 34<a>, the amount of lost motion between them being variable by withdrawing the pin 35 and adjusting the angle between the arms. The ratchet - wheel 33<c> is operated by a short pawl 30 on the slide 17 until the pawl 15<h> is brought into the path of a long pawl 30<1>. This then gives a rapid movement through an angle equal to one of the teeth 14, at the same time depressing the pawl 15<h> into engagement with the wheel 18, so turning the cam - shafts and operating the catch which engages the lever 9, Fig. 1, to lower the valve 6 and apply the high pressure. The slow motion of the ratchet-wheel 33<c> then continues until the arm 33<a> engages the pin 18<1> and, at this point, a tooth (not shown) on the inner face of the ring 33<c> comes into the path of the pawl 40<1> which gives a second rapid movement of the cam-shafts releasing the pressure in the power-chamber and bringing the teeth 14 again into operation. The intervals before the applicatioo and release of pressure may be increased by putting a pawl 72 into action with a ratchet-wheel 71, which rotates a cam 70 to lift the pawl 30 and render it inactive during three strokes of the carrier, every fourth stroke only producing a movement of the ratchet - wheel 33<c>. If it is desired to vary the time of initial application of pressure, the last tooth 15, Fig. 10, is removed and a slow-motion gear employed similar to that described but having in addition a lost-motion device between the ratchet-wheel 33<c> and the arm 33<a> consisting of a lug attached to the arm and arranged between two lugs, one on the rim 33<c> and the other on a ring adjustably clamped to the rim 33<c>, there being two pawls 15<h> independently adjustable on the rim 34.