EP0017628A1

EP0017628A1 - Pneumatic activating device

Info

Publication number: EP0017628A1
Application number: EP80830016A
Authority: EP
Inventors: Massimo Cassinari
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-04-10
Filing date: 1980-03-22
Publication date: 1980-10-15

Abstract

The invention is constituted by a pneumatic activating device able to transform a straight movement into a rotary movement, wherein the device is of a compact type and comprises in reciprocal cooperation and coordination:

- a plurality of shafts or arms (22-23) located in the piston-disks (19) and stretching towards the other piston-disk (19), at least one shaft (22) per piston having equipment (29-31) fitted to it,
- one single feed duct (15) for the two end chambers (18)
- and feed inlets (13-14) located near to each other (Figure 4), whereby at least one return spring (25-125) can be included.

Description

The subject of this invention is a pneumatic device causing activation by means of a rotary motion; to be more - precise, the invention concerns a pneumatic device able to bring about a rotary motion to be employed, for instance, to activate valves or other apparatus.
Many devices are commercially available that produce activation with a rotary motion and use two opposed pistons .which, through the action of a fluid, move with an alternate straight, up-and-down movement in a cylinder.
This straight movement is transformed into a rotary .movement by means of devices which may be a piston with a slotted link or a piston with a rack.
The most frequent shortcoming of these devices, which .comprise a pair of pistons having an alternating movement .in a cylinder, consists in the tendency of two pistons to lose their alignment or to swivel in the cylinder, with the outcome that they seize up and/or damage the inner surfaces .of the cylinder, thereby impairing the good watertight seal .of the same.
A further drawback, which often happens in these types of devices fed with a fluid, lies in the fact that the moving parts are hard to lubricate as the lubricant tends to be drawn away by the pressure of the fluid, with the outcome that the pistons may seize up in the cylinder. Said devices. often involve the further shortcoming that a plurality of outside feed pipes has to be fitted so that the fluid can be introduced at one and the same time into the two chambers opposite the pistons so that the latter can be provided with the movement towards each other which is needed to transmit the rotary movement to the primary shaft.
With reference to the foregoing the author has conceived and designed a pneumatic activating device providing a rotary motion, which can make use of the crank and slotted link system or the rack system to transform a straight movement into a rotary movement, as said earlier.
According to the invention the pistons have a plurality of guide shafts arranged perpendicularly to the disk which acts as a piston; the shafts of one disk are oriented towards the other disk but are advantageously offset in respect of the shafts of the disk towards which they are orient- .ed. The shafts lie parallel to each other but, as said, are- advantageously staggered at different angles.
Moreover, the shafts have different sizes, and one or more guide shafts can be used to transmit motion to a slot- .ted link or to a pinion.
According to the invention one or more springs may be visualized as being located between the disk acting as a piston and the corresponding end of the cylinder.
According to a variant said springs can be envisaged as .being positioned between the disks acting as pistons or be- .tween the disks and the axle which takes the rotary motion .to the outside.
According to the invention the feed for the two chambers lying between the disks acting as pistons and the corresponding ends of the cylinder is realized with a duct made in the jacket of the cylinder, so that only one feed is needed for. both chambers.
According to the invention once more, the hole to feed. the chamber lying between the two disks acting as pistons is advantageously located near to the feed for the two end chambers.
The invention tends, therefore, to provide many advantages and benefits for an end-user inasmuch as the latter can .avoid frequent checking and maintenance operations, difficult and costly connections and the disadvantage of being condit--ioned by the device, and- so forth.
Furthermore, the invention has the aim of making the drive suitable for the requirements of the user by simply changing some parts and leaving the rest unaltered.
Therefore, the invention is formed with a pneumatic activating device suitable for transforming a straight movement -into a rotary movement, whereby the deuice is compact and is characterized by having in reciprocal cooperation and coordination:

- a plurality of shafts or arms present in the piston-disks and stretching towards the other piston-disk, at least one shaft per piston having equipment fitted to itself,
- one single feed duct for both end chambers and
- feed inlets positioned near to each other,

Let us now see some variants of the invention with the help of the attached tables, which have been given as non- restrictive examples.
In the figures we have the following:

.Fig.I shows a device with a rack-type drive at the outer end of its run.
Fig.2 shows the example of Fig.I at the inner end of its run.
Figs. 3a & 3b show two possible lay-outs of the shafts.
Fig.4 shows a cross section along the axle providing output. of the motion.
Fig.5 shows a variant using a slotted link at the outer end of its run.
Fig.6 shows the example of Fig.5 with the pistons at the .inner end of their run.
Fig.7 shows a cross section along the axle providing output. of the motion.

As regards the figures, the same parts or parts having. the same functions bear the same reference numbers. In the figures we have as follows: IO is generically the device: .II is the jacket of the cylinder 12: I3 is the inlet hole for the fluid to reach the chamber I7 between the two pis- .tons: I4 is the inlet hole cooperating with the duct I5 and .outlet I6 to feed the fluid into the end chambers I8: I7 is .the chamber between the two pistons I9: I8 are the chambers -between the pistons I9 and the ends of the cylinder I2: I9- are the pistons and consist of a disk 2I and a plurality of arms of which at least one 22 is equipped with fittings, whilst the others 23 act only as guides: 20 are the ends of -the cylinder and are fixed in a known manner to the jacket and may include seatings 24 for a plurality of springs 25 to be fitted: 2I is the disk constituting the piston and may itself too have one or more sunken areas for springs 25-125, and said springs 25-I25 may be located between the disk and .the end 20 or between one disk and the other disk or, yet again, between the disk and a support which is advantageously positioned on and able to revolve on the shaft 26 providing the output of the motion: moreover, the disk has at least - one packing 27, which is advantageously of a known type such as an 0-ring, and an annular antifriction ring 28, which serves to lessen the need for lubrication: 22-122-222 are the arms equipped with fittings and may be equipped only with a. rack 29 able to cooperate with a pinion 30 integral with or. fixed solidly to the shaft 26 or only with a pin 31 with a . possible bush 32 or with a pin 3I and rack 29; said equipped arms will comprise advantageously some antifriction pads 33: 23 are the unequipped guide arms and may be one or more in number per disk 19; they too have antifriction pads 33 and can cooperate with arms 22 to limit the run of the disks 19; said arms 23 can be staggered and may, in that case, be long or else may coincide with each other, in which case they will be shorter: 24-124 are possible sunken areas wherein the springs 23-125 are seated: 25-125 are springs which serve to keep the device in a normal position and may be located between the disk I9 and the corresponding end 20 or between one disk 19 and the other or else between a disk and an appropriate support positioned around the shaft 26: 26 is the motion output shaft and cooperates with packings 127 to re- .tain a watertight seal and may be equipped with a pinion 30. .or a slotted link 130, depending on the law of rotation to . be imparted to the axle 26: 27-127 are sealing packings of any desired type, which will advantageously but not essentially.be of an 0-ring type: 28 and 33 are antifriction means: 29 is the rack: 30 is a pinion integral with or fixed solidly to the shaft 26, whereas 130 is a slotted link which too' is integral with or fixed solidly to the shaft 26: 31 is a pin with a bush 32,
According to the invention the inlet holes 13 and 14 may be made near to each other and pre-arranged for an electric valve to be fitted.
According to the invention once more', the arms I22 may be equipped so as to perform the work of the arms 22 (rack and pinion) or of the arms 222 (crank pin and slotted link).
The working of the device is simple and obvious and has not been described here.
Here we have described some preferential solutions, but variants are possible; thus the proportions and sizes can be altered and any desired combination of parts can be realized, and so on. These and other variants are all possible to a . technician in this field without departing thereby from the- idea of the solution.

Claims

1. Pneumatic activating device able to transform a straight movement into a rotary movement, being of a compact type and characterized by comprising in reciprocal cooperation and coordination:

- a plurality of shafts or arms (22-23) located in the piston-disks (19) and stretching towards the other piston-disk (19), at least one shaft (22) per piston having equipment (29-31) fitted to it,

- one single feed duct (15) for both end chambers (18),

- feed inlets (13-14) positioned near to each other (Fip.4), whereby at least one return spring (25-125) may be included.

2. Pneumatic activating device, as in Claim I, characterized by the fact that the equipped shafts or arms (22) are equipped with a rack (29) and cooperate with a pinion (30) (Figs. I and 2).

3. Pneumatic activating device, as in Claim 1, characterized by the fact that the equipped shafts or arms (22) are equipped with pins (31) and cooperate with a slotted link (130) Figs. 5, 6 and 7).

4. Pneumatic activating device, as in Claim 1, characterized by the fact that the equipped shafts or arms (22) are equipped with a rack (29) and pins (31) and can cooperate equally well with a pinion (30) or slotted link (130),

5. Pneumatic activating device, as in Claim I and in one or another of the Claims thereafter, characterized by the fact- that the pistons (19) comprise an antifriction ring (28).

6. Pneumatic activating device, as in Claim I and in one or. another of the Claims thereafter, characterized by the fact. that the shafts or arms (22-23) comprise at least one anti-. .friction pad (33) (Fig.3).

.7. Pneumatic activating device, as in Claim I and in one or. .another of the Claims thereafter, characterized by the fact .that the hole to feed fluid (14) into the end chambers (18) cooperates with a duct (I5) in the jacket of the cylinder (II) (Fig.I).

.8. Pneumatic activating device, as in Claim I and in one or. .another of the Claims thereafter, characterized by the fact. that the holes (13-14) to feed fluid are located near to each .other and are pre-arranged advantageously to cooperate with. .an electric valve.

.9. Pneumatic activating device, as in Claim I and in one or .another of the Claims thereafter, characterized by compris- .ing a plurality of springs (25) between a piston (19) and an end (20) (Fig.6).

10. Pneumatic activating device, as in Claim I and in one or .another of the Claims thereafter up to Claim 8 inclusive, .characterized by comprising at least one spring between piston (19) and piston (19).

II. Pneumatic activating device, as in Claim I and in one or another of the Claims thereafter up to Claim 8 inclusive, .characterized by comprising at least one spring (125) between piston (19) and output shaft (26) (Figs. 6 and 7).