Pumping Apparatus

Abstract

An artificial respirator including a pump assembly, a piston of which is connected to a first axially movable rod, a second axially movable rod, pivotal lever means interconnecting the rods, the pivot point of said lever means being adjustable to effect variation in the volume of gas pumped by the pump means, a second lever pivotally connected to the second rod, an adjustable fulcrum for the second lever and a rotary link operatively connected to the second lever whereby upon rotation of the link movement is imparted to the second rod, the fulcrum point of the second lever being adjustable to vary the timing of the forward and return motion of the pump means.

Description

This invention relates to artificial respirators and has for its object to provide such a respirator in a simple and convenient form.

An artificial respirator in accordance with the invention comprises in combination, a first axially movable rod operably connected to a pump mechanism, a second axially movable rod disposed in spaced substantially parallel relationship to the first rod, a first lever acting intermediate said rods, a first adjustable fulcrum for the first lever whereby the extent of axial movement of the first rod for a given axial movement of the second rod can be adjusted, a second lever pivotally connected to the second rod, a second adjustable fulcrum for said second lever and a driven rotary arm having sliding connection with said second lever and the arrangement being that variation of said second fulcrum will effect variation in the ratio of the times of forward and reverse movement of the rods.

In the accompanying drawings:

FIG. 1 is a front elevation of one example of an artificial respirator in accordance with the invention with parts removed for the sake of clarity,

FIG. 2 is a side view of the left hand portion of the apparatus of FIG. 1 looking towards the left of FIG. 1,

FIG. 3 is a side view of the right hand portion of the apparatus of FIG. 1 looking towards the left of FIG. 1,

FIG. 4 is a diagram showing the air circuit of the respirator,

FIG. 5 is a perspective view of a portion of the respirator of FIG. 1 showing a modification.

The artificial respirator shown in the drawings was designed for use with infants but by modification to pump larger quantities of air it can be used on adult persons. As with all respirators it is essential to be able to vary the frequency of pumping as well as the volume and also the ratio between inspiration and expiration. It is desirable to be able to adjust these three variables independently of each other and the respirator now to be described has this facility.

The respirator comprises a base board 10 which can be mounted in any desired attitude, it being shown vertical in the drawings. Mounted upon the base board is a piston cylinder combination 11 which includes a piston 12 slidable within a cylinder 13. The piston is connected to a piston rod 14 which extends from the cylinder and which is pivotally connected to a guide 15 mounted for sliding movement by a pair of spaced guide bars 16. The guide 15 and the piston rod 14 constitute a first axially movable rod, the pivotal connection between the two components being provided to accommodate any slight misalignment.

There is also provided a second axially movable rod which is constrained for movement in a axis parallel to but spaced from the axis of movement of the first rod. The second rod is shown at 17 and is formed in two parts 18 and 19. Part 18 is of cylindrical rod like form and is journalled in a bearing block 20a secured to the base board 10. Part 19 is a flat bar which is rigidly united with the part 18. Interconnecting the two rods is a first lever 20 which is pivotally connected to the rod 17 at a pivot 21. At its other end portion the lever 20 is of cylindrical form and it is slidably accommodated within a bush 22 which is pivotally connected to the guide 15. Intermediate its ends the lever 20 extends through a bush 23 which is pivotally mounted upon an adjustable support 24. The support 24 is adjustably mounted upon a pair of spaced locating bars 25. The support 24 is provided with a clamping screw 26 which can be slackened to permit adjustment of the position of the support on the locating bars.

The respirator includes a second lever 27 which is formed as two rigidly united parts 28, 29. Part 28 is a flat bar which is pivotally connected at 30 to the part 19 of the rod 17. The part 29 of the lever 27 is slidably accommodated within a bush 31 which is pivotally mounted upon a further support 32 which is adjustably mounted on a pair of spaced locating bars 33. The bars 33 as also the bars 25 extend in a direction substantially normal to the axes of movement of the rods. The support 32 includes a clamping screw 34 which can be slackened to allow adjustment of the position of the support on the bars 33.

In order to power the apparatus an electric motor 35 is mounted upon the base board 10. The motor has an output shaft 36 which mounts a radially disposed arm 37. The arm 37 is coupled to the lever 29 by means of a sliding slotted pivot member 38 which ensures that the member can move over the whole length of the part 28 of the lever 27. The speed of the motor is adjustable and in operation, as the output shaft 36 of the motor rotates the second rod 17 will be reciprocated. The relative times of forward and reverse movement can be adjusted by altering the position of the support 32. Reciprocation of the lever 17 will effect by way of the lever 20 reciprocation of the guide 15 and piston rod 14. The relative magnitude of the reciprocation of the rods is adjusted by altering the position of the support 24.

In the manner described above the volume of air displaced by the piston 12 can be adjusted by altering the position of the support 24, the rate of pumping of the piston is controlled by altering the speed of the motor and the ratio of the times for forward and reverse movement of the piston which corresponds to the inhalation and expiration ratio can be adjusted by altering the setting of the support 32.

The cylinder is provided with inlet and outlet passages 39, 40 and these are provided with one way valves 41, 42 respectively (FIG. 4) which are accommodated within a valve housing 43 mounted upon the end closure of the cylinder. The passage 39 is connected to a source of air or other gas with which it is desired to ventilate the infant and the passage 40 is connected to a tube 44 which is inserted in the windpipe of the infant. In addition passage 40 communicates with a solenoid operated valve 45 and if desired, with a restrictor 46. The operation of the solenoid valve is controlled by a switching system (not shown) triggered by two micro-switches which are actuated by an arm on the rod 17.. During the return motion of the piston 12 the valve 42 is closed and the lungs of the infant deflate, the air passing through the solenoid operated valve 45 and the restrictor 46. During the forward or pumping stroke of the piston the valve 41 is closed and also the valve 45 so that the air is delivered to the infants lungs. A safety valve 47 is provided to relieve excess pressure should this develop.

The restrictor 46 acts to control the expiration flow and if desired can be adjusted during the expiration of air. For this purpose and as shown in FIG. 5 there is provided on the rod 17 a cam plate 48 which is secured to the parts 18, 19 of the rod 17 and which is slidable within a groove formed in the block 20a. The cam 48 is provided with a contoured cam surface 49 against which bears a roller 50 mounted upon a rod 51 slidable within the block 20a. The rod 51 is loaded by a coiled compression spring 52 which maintains the roller 50 in contact with the cam surface 49. The free end of the rod 51 is curved for co-operation with a flexible tube 52. The rod acts to squeeze the tube against an abutment (not shown) thereby to constitute the restrictor 46. As shown the degree of restriction decreases as the suction stroke of the piston progresses.

Should the gas volume measurement exceed the capabilities of the equipment, then a further piston cylinder combination may be connected to rod 17 and coupled by suitable valving to the piston cylinder combination and to supplement the capacity of the respirator.

Claims

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An artificial respirator comprising in combination a pump mechanism including an expansible and contractible working chamber, means whereby the working chamber may be connected to a patient, further means whereby the working chamber may be connected to a source of gas, a first axially movable rod operably connected to the pump mechanism, a second axially movable rod disposed in spaced substantially parallel relationship to the first rod, a first lever acting intermediate said rods, a first adjustable fulcrum for the first lever whereby the extent of axial movement of the first rod for a given axial movement of the second rod can be adjusted, a second lever pivotally connected to the second rod, a second adjustable fulcrum for said second lever and a driven rotary arm having sliding connection with said second lever and the arrangement being that variation of said second fulcrum will effect variation in the ratio of the times of forward and reverse movement of the rods.

2. A respirator as claimed in claim 1 in which the fulcra are adjustable along lines normal to the direction of movement of the rods.

3. A respirator as claimed in claim 2 in which the driven rotary arm is mounted on the output shaft of a motor.

4. A respirator as claimed in claim 2 in which the fulcra are defined by bushes through which the levers pass, the bushes being pivotally mounted upon adjustably mounted support plates.

5. A respirator as claimed in claim 1 in which the pump mechanism includes a piston reciprocably mounted within a cylinder.

6. A respirator as claimed in claim 5 including a valve controlled inlet and a valve controlled outlet passage to said cylinder.

7. A respirator as claimed in claim 6 including a further valve which is closed during the delivery of gas through the outlet passage and which is opened during flow of gas through the inlet passage, said further valve being connected in series with said outlet passage, a branch passage being provided from said outlet passage intermediate said valve and said further valve for connection to the windpipe of the person to be ventilated.

8. A respirator as claimed in claim 7 in which said further valve is a solenoid valve, switch means being provided to control the operation of said further valve.

9. A respirator as claimed in claim 8 including a restrictor in said outlet passage for controlling the flow of gas through said further valve.

10. A respirator as claimed in claim 9 in which said restrictor is adjustable to afford varying restriction to the flow of gas during the flow of gas through the inlet passage.

11. A respirator as claimed in claim 10 in which the restrictor is controlled by a cam movable with said second rod.