GB1603246A - Device for introducing lubricating oil into pneumatic pipes - Google Patents

Description

(54) DEVICE FOR INTRODUCING LUBRICATING OIL INTO PNEUMATIC PIPES (71) We, VEB KOMBINAT UM FORMTECHNIK "HERBERT WARNKE" ERFURT, 1 Schwerborner Strasse, 50 Erfurt, German Democratic Republic, a Corporation organised under the laws of the German Democratic Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a device for introducing lubricating oil into pneumatic pipes, more particularly on mechanical presses in order to lubricate pneumatically operable mechanisms such as a clutch, a brake or a ram balancing mechanism.

It is known to enrich the compressed air with oil for the purpose of lubricating pneumatically actuated mechanisms. In devices of this type, wick oilers or mist oilers are incorporated in the pneumatic pipes. The principle of operation of such wick or mist oilers is based upon the fact that the suction of the pneumatic stream continuously entrains small quantities of the oil out of wicks or atomiser nozzles projecting into the pipe, whilst the quantity of the oil introduced is a function of the flow conditions and of the duration of the flow. For an extremely short duration of the flow a response of the mist oilers is not always ensured, so that satisfactory lubrication is not achieved, e.g., in the case of the extremely short switching times of clutches or brakes on presses.

In another known device for lubricating intermittently operated pneumatic mechanisms, more particularly portable machine tools driven by a pneumatic motor, according to Federal German specification 2 553 168, the aim is achieved in that an injection oiler constructed as a piston pump and known per se, comprising a piston ground into a bore which forces oil through said bore via a springloaded non-return valve into the pneumatic pipe, is arranged as lubricating device in the housing of the mechanism to be lubricated, which is controlled by the operating device for switching the latter on and off.

A considerable disadvantage of this latter device lies in the fact that the piston does not suck any oil during the return stroke, but operates against a vacuum by means of spring force. If the piston is ground relatively snugly into the bore, the injection of a precisely dosed quantity of oil is in fact possible, but the time for the return stroke of the piston is very long due to the extremely slow influx of leakage oil between piston wall and bore, so that the lubricating device is only again ready for service at fairly long time intervals.

However, if the piston is ground into the bore with such play that a rapid and certain return of the piston is obtained due to the influx of leakage oil into the bore, then the injection of a precisely dosed quantity of oil is no longer possible due to the leakage losses.

A further disadvantage of the lubricating device lies in the fact that due to the direct control by the on and off switching device of the mechanism, fundamentally only one stroke of the piston of the lubricating device occurs per switching-on process.

The invention aims at producing a structurally simple and functionally reliable lubricating device with which the introduction of precisely dosed quantities of oil into pneumatic pipes can be achieved irrespectively of the flow conditions and of the duration of the flow.

According to one aspect of the present invention, there is provided a device for introducing lubricating oil into a pneumatic pipe, comprising: a pump casing having an upper part defining a first cylinder chamber, an intermediate part defining an oil inlet chamber and a lower part defining a second cylinder chamber of smaller diameter than the first chamber, bores connecting to the first chamber whereby a piston in said chamber can be driven up and down when said bores are connected to a valve controlled air supply, a connecting bore for the oil inlet cham ber, whereby said oil inlet chamber is connectible to an oil supply, and an oil outlet bore from the lower cylinder chamber which is connectable to the pneumatic pipe to be lubricated; lip sealing rings which are disposed respectively between the two cylinder chambers and the oil inlet chamber and between the lower cylinder chamber and the oil outlet bore, of which the second and third lip sealing rings which close the lower cylinder chamber perform the function of non-return valves; and a piston rod whose upper end is rigidly connected to the aforementioned piston and whose lower end is disposed in its uppermost position in the oil inlet chamber and during a downward stroke enters into the lower cylinder chamber through the intervening second lip sealing ring, thereby to deliver a predetermined quantity of oil into the lower chamber and to force said oil into the oil outlet bore through the intervening third lip sealing ring.

According to a second aspect of the invention, there is provided a device for introducing lubricating oil into a pneumatic pipe, comprising: a pump casing having an upper part defining a cylinder chamber and a lower part defining an oil inlet chamber, bores connecting to the cylinder chamber whereby a piston in said chamber can be driven up and down when said bores are connected to a valve controlled air supply, a connecting bore for the oil inlet chamber whereby said oil inlet chamber is connectible to an oil supply, and an oil outlet bore from the oil inlet chamber, the pump casing being mounted to the pneumatic pipe to be lubricated so that the oil outlet bore opens into said pipe; first and second lip sealing rings between the oil inlet chamber and the cylinder chamber and between the oil inlet chamber and the pneumatic pipe; a piston rod whose upper end is rigidly connected to the aforementioned piston and whose lower end protrudes into the pneumatic pipe in all positions of the strokes of said piston rod whereby said piston rod during a downward stroke entrains a quantity of oil, in the form of a film of oil adhering to its lower end surface, through the second lip sealing ring, while, during the following upward stroke of the piston rod, the film of oil is scraped off by said second lip sealing ring to emerge from the oil outlet bore into the pneumatic pipe and be entrained by the flow of air therein.

In both aspects, the invention provides a pneumatically controlled piston rod which, through the unique use of lip sealing rings, enables a desired quantity of lubricating oil to be delivered to the pneumatic pipe without creating difficulty in relation to fast repetition action.

In order that the invention may be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example two embodiments thereof, and in which: Fig. 1 is an axial section of one embodiment of injection pump; Fig. 2 is a block circuit diagram of the lubricating device; and Fig. 3 is an axial section of another embodiment of injection pump without suction chamber and non-return valve mounted directly upon a pneumatic pipe.

The lubricating device comprises a pneumatically operable injection pump 16 and a corresponding control device. As can be seen from Fig. 2, a plurality of injection pumps 16 are preferably arranged in an oil tank 15 and connected by lubricating pipes to the lubrication point. However the injection pump 16 may also be arranged directly at the lubrication point and be connected to the oil tank 15 by a feed pipe. Any desired number of injection pumps 16 may be operated through a multiple-way valve 17. A pulsator 18 determines the interval of the lubrication pulses as a function of the stroke frequency of the mechanism to be lubricated such as a press 19.

Referring now to Fig. 1, a piston rod 1 is arranged in a lower cylinder chamber 8 provided in the bottom section of a pump housing 16a. The lower cylinder chamber 8 is sealed by a lip sealing ring 6 with respect to a pressureless oil inlet chamber 5 filled with oil, and by a lip sealing ring 7 with respect to an oil outlet bore 9. A piston 2 which can be subjected to pneumatic pressure on both sides, which is rigidly attached to the piston rod 1, is arranged in an upper cylinder chamber 3 provided in the top section of the pump housing 16a. The surface area of the piston 2 is considerably greater than the surface area of the piston rod 1 in order to generate an adequate oil pressure. The upper cylinder chamber 3 is filled with compressed air and is sealed by a lip sealing ring 4 with respect to the oil inlet chamber 5 filled with oil.Exchangeable spacer rings or spacer washers 11, with which the stroke of the piston 2 and hence the quantity of oil to be pumped per stroke can be varied, are arranged beneath or above the piston 2 in the upper cylinder chamber 3.

As soon as the piston 2 is pneumatically actuated on its underside through a connecting bore 13, it moves upwards together with the piston rod 1. This generates a negative pressure in the lower cylinder chamber 8 and oil flows out of the oil tank 15 through an oil inlet bore 12 into the oil inlet chamber 5 and from there through the lip sealing ring 6, which acts as a non-return valve, into the lower cylinder chamber 8. At this time the piston 2 is in its top position, and likewise the piston rod 1, the lower end of the latter thus being disposed above the lip sealing ring 6 to enable free - flow of oil into the lower cylinder chamber 8. After the muitiple-way valve 17 is changed over the piston 2 is pneu matically actuated on its upper side through a connecting bore 14 and is relieved on its underside and moves downwards together with the piston rod 1.A precisely dosed quantity of the oil present in the lower cylinder chamber 8 is then fed through the lip sealing ring 7, the oil outlet bores 9 and 10 and the lubricating pipe leading to the lubrication point, to the pneumatic pipe. In this arrangement the inner lip ring 7 acts as a non-return valve, the opening pressure of which is a function of the counterpressure propagated through the oil outlet bores 9 and 10.

In the embodiment illustrated in Fig. 3 like parts are indicated by the like reference characters. In this embodiment in which the lower cylinder chamber 8 and the lip sealing ring 7 acting as a non-return valve are omitted, the pump is mounted directly upon a pneumatic pipe 20 to be lubricated. The oil inlet chamber 5 is sealed by the lip sealing rings 4 with respect to the cylinder chamber 3 and by the lip sealing ring 6 with respect to the pneumatic pipe 20. The piston rod 1 is of such a length that its lower end is still located in the pneumatic pipe 20 even in the highest position of the piston 2. When the piston 2 moves downwards the piston rod 1 entrains a lubricant film on its envelope surface through the sealing gap of the lip sealing ring 6 into the pneumatic pipe 20.During the upward. stroke of the piston rod 1 the lubricant film is scraped off at the sealing edge of the lip sealing ring 6 and entrained by the pneumatic stream. The quantity of oil to be pumped per stroke is conveniently dosed so that one pump stroke is required for each switching of the pneumatically actuated mechanism, so that no separate control device is necessary and a direct actuation of the pump through the control pipes of the pneumatically actuated mechanism can occur.

WHAT WE CLAIM IS: 1. A device for introducing lubricating oil into a pneumatic pipe, comprising: a pump casing having an upper part defining a first cylinder chamber, an intermediate part defining an oil inlet chamber and a lower part defining a second cylinder chamber of smaller diameter than the first chamber, bores connecting to the first chamber whereby a piston in said chamber can be driven up and down when said bores are connected to a valve controlled air supply, a connecting bore for the oil inlet chamber, whereby said oil inlet chamber is connectible to an oil supply, and an oil outlet bore from the lower cylinder chamber which is connectible to the pneumatic pipe to be lubricated; lip sealing rings which are disposed respectively between the two cylinder chambers and the oil inlet chamber and between the lower cylinder chamber and the oil outlet bore, of which the second and third lip sealing rings which close the lower cylinder chamber perform the function of non-return valves; and a piston rod whose upper end is rigidly connected to the aforementioned piston and whose lower end is disposed in its uppermost position in the oil inlet chamber and during a downward stroke enters into the lower cylinder chamber through the intervening second lip sealing ring, thereby to deliver a predetermined quantity of oil into the lower chamber and to force said oil into the oil outlet bore through the intervening third lip sealing ring.

2. A device as claimed in claim 1, wherein the stroke of the piston and hence the quantity of oil to be pumped per stroke is adjustable by the insertion of exchangeable spacer rings or spacer washers of differing thicknesses above or beneath the piston in the cylinder chamber.

3. A lubrication control system which comprises a plurality of devices according to claim 1 or claim 2 controlled by a multiple-way valve operable by a pulsator.

4. A device for introducing lubricating oil into a pneumatic pipe, comprising: a pump casing having an upper part defining a cylinder chamber and a lower part defining an oil inlet chamber, bores connecting to the cylinder chamber whereby a piston in said chamber can be driven up and down when said bores are connected to a valve controlled air supply, a connecting bore for the oil inlet chamber, whereby said oil inlet chamber is connectible to an oil supply, and an oil outlet bore from the oil inlet chamber, the pump casing being mounted to the pneumatic pipe to be lubricated so that the oil outlet bore opens into said pipe; first and second lip sealing rings between the oil inlet chamber and the cylinder chamber and between the oil inlet chamber and the pneumatic pipe; a piston rod whose upper end is rigidly connected to the aforementioned piston and whose lower end protrudes into the pneumatic pipe in all positions of the strokes of said piston rod whereby said piston rod during a downward stroke entrains a quantity of oil, in the form of a film of oil adhering to its lower end surface, through the second lip sealing ring while, during the following upward stroke of the piston rod, the film of oil is scraped off by said second lip sealing ring to emerge from the oil outlet bore into the pneumatic pipe and be entrained by the flow of air therein.

5. A device as claimed in claim 4, wherein the stroke of the piston and hence the quantity of oil to be pumped per stroke is adjustable by the insertion of exchangeable spacer rings or spacer washers of differing thicknesses above or beneath the piston in the cylinder chamber.

6. A lubrication control system which comprises a plurality of devices according to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. matically actuated on its upper side through a connecting bore 14 and is relieved on its underside and moves downwards together with the piston rod 1. A precisely dosed quantity of the oil present in the lower cylinder chamber 8 is then fed through the lip sealing ring 7, the oil outlet bores 9 and 10 and the lubricating pipe leading to the lubrication point, to the pneumatic pipe. In this arrangement the inner lip ring 7 acts as a non-return valve, the opening pressure of which is a function of the counterpressure propagated through the oil outlet bores 9 and 10. In the embodiment illustrated in Fig. 3 like parts are indicated by the like reference characters. In this embodiment in which the lower cylinder chamber 8 and the lip sealing ring 7 acting as a non-return valve are omitted, the pump is mounted directly upon a pneumatic pipe 20 to be lubricated. The oil inlet chamber 5 is sealed by the lip sealing rings 4 with respect to the cylinder chamber 3 and by the lip sealing ring 6 with respect to the pneumatic pipe 20. The piston rod 1 is of such a length that its lower end is still located in the pneumatic pipe 20 even in the highest position of the piston 2. When the piston 2 moves downwards the piston rod 1 entrains a lubricant film on its envelope surface through the sealing gap of the lip sealing ring 6 into the pneumatic pipe 20.During the upward. stroke of the piston rod 1 the lubricant film is scraped off at the sealing edge of the lip sealing ring 6 and entrained by the pneumatic stream. The quantity of oil to be pumped per stroke is conveniently dosed so that one pump stroke is required for each switching of the pneumatically actuated mechanism, so that no separate control device is necessary and a direct actuation of the pump through the control pipes of the pneumatically actuated mechanism can occur. WHAT WE CLAIM IS:

1. A device for introducing lubricating oil into a pneumatic pipe, comprising: a pump casing having an upper part defining a first cylinder chamber, an intermediate part defining an oil inlet chamber and a lower part defining a second cylinder chamber of smaller diameter than the first chamber, bores connecting to the first chamber whereby a piston in said chamber can be driven up and down when said bores are connected to a valve controlled air supply, a connecting bore for the oil inlet chamber, whereby said oil inlet chamber is connectible to an oil supply, and an oil outlet bore from the lower cylinder chamber which is connectible to the pneumatic pipe to be lubricated; lip sealing rings which are disposed respectively between the two cylinder chambers and the oil inlet chamber and between the lower cylinder chamber and the oil outlet bore, of which the second and third lip sealing rings which close the lower cylinder chamber perform the function of non-return valves; and a piston rod whose upper end is rigidly connected to the aforementioned piston and whose lower end is disposed in its uppermost position in the oil inlet chamber and during a downward stroke enters into the lower cylinder chamber through the intervening second lip sealing ring, thereby to deliver a predetermined quantity of oil into the lower chamber and to force said oil into the oil outlet bore through the intervening third lip sealing ring.

2. A device as claimed in claim 1, wherein the stroke of the piston and hence the quantity of oil to be pumped per stroke is adjustable by the insertion of exchangeable spacer rings or spacer washers of differing thicknesses above or beneath the piston in the cylinder chamber.

3. A lubrication control system which comprises a plurality of devices according to claim 1 or claim 2 controlled by a multiple-way valve operable by a pulsator.

4. A device for introducing lubricating oil into a pneumatic pipe, comprising: a pump casing having an upper part defining a cylinder chamber and a lower part defining an oil inlet chamber, bores connecting to the cylinder chamber whereby a piston in said chamber can be driven up and down when said bores are connected to a valve controlled air supply, a connecting bore for the oil inlet chamber, whereby said oil inlet chamber is connectible to an oil supply, and an oil outlet bore from the oil inlet chamber, the pump casing being mounted to the pneumatic pipe to be lubricated so that the oil outlet bore opens into said pipe; first and second lip sealing rings between the oil inlet chamber and the cylinder chamber and between the oil inlet chamber and the pneumatic pipe; a piston rod whose upper end is rigidly connected to the aforementioned piston and whose lower end protrudes into the pneumatic pipe in all positions of the strokes of said piston rod whereby said piston rod during a downward stroke entrains a quantity of oil, in the form of a film of oil adhering to its lower end surface, through the second lip sealing ring while, during the following upward stroke of the piston rod, the film of oil is scraped off by said second lip sealing ring to emerge from the oil outlet bore into the pneumatic pipe and be entrained by the flow of air therein.

5. A device as claimed in claim 4, wherein the stroke of the piston and hence the quantity of oil to be pumped per stroke is adjustable by the insertion of exchangeable spacer rings or spacer washers of differing thicknesses above or beneath the piston in the cylinder chamber.

6. A lubrication control system which comprises a plurality of devices according to

claim 4 or claim 5 controlled by a multipleway valve operable by a pulsator.

7. A device for introducing lubricating oil into a pneumatic pipe substantially as hereindescribed with reference to and as shown in Figs. 1 and 2 or Fig. 3 of the accompanying drawings.