DE29623670U1 - Automatic lubricant dispenser - Google Patents

Description

· Hamburg, 10 December 1 998 * · i « —·-·_ » ₉
• .* - * * ··"
· · · · » Bremen
Patent attorneys I Eisenführ, Speiser & Partner : ···· · ··· y§ ⁱ i ⁱ t ^Ljr9 * · ·
Patent Attorney * ·· European Patent Attorneys ··· · Dipl.-Phys. Frank Meier Dipl.-Ing. Günther Eisenführ . Our sign: DH 103 FM/nne Dipl.-Ing. Dieter K. Speiser Lawyers Dr.-Ing. Werner VV. Rabus Applicant/Owner: DÖHRING, Gerhard Christian Spintig Dipl.-Ing. Jürgen Brügge Official reference number: New registration Rainer Boehm Dipl.-Ing. Jürgen Kühnhard* Dipl.-Ing. Klaus G. Göken Ballindamm 3 Jochen Ehlers D-20095 Hamburg Patent attorneys Phone +49-10I40-309 7440 Dipl.-Ing. Mark Andres Fax +49-10)40-3097 4444 Dipl.-Ing. Joachim von Oppen mail@eiseniuhr.com Lawyers Ulrich H. Sander Sabine Richter Munich Patent attorneys European Patent Attorneys Dipl.-Wirtsch.-Ing. Rainer Fritsche
Lbm.-Chem. Gabriele Leißler-Gerstl Patent Attorney Dipl.-Chem. Dr. Peter Schuler Berlin Patent Attorney
European Patent Attorney Dipl.-Ing. Jutta Kaden Alicante European Trademark Attorney Dipl.-Ing. Jürgen Klinghardt Gerhard Döhring, Blotter Weg 154, 45478 Mühlheim a.d. Ruhr Device for automatic lubricant dispensing

The invention relates to a device for automatically dispensing lubricant with a piston arranged in a cylinder and a drive means connected to it. Such a device is known from DE-PS-43 21 452 or DE-U-92 14 096. While DE-PS-43 21 452 proposes a solution in which lubricant is pressed directly out of the cylinder by means of a pressure piston, i.e. the lubricant is located directly in the cylinder, the solution according to DE-U-92 14 096 proposes inserting a lubricant pack into the cylinder and pressing it out by means of a piston.

Both known solutions have several disadvantages. The disadvantage of the solution according to DE-PS-43 21 452 is that when the lubricant is pressed out of the cylinder, the piston is subjected to very different stresses due to its geometric shape and tends to tip slightly at the outer edge, which is opposite the inner cylinder wall, or to create a gap between the piston and the inner cylinder wall, through which the lubricant can get into the area of the drive. In any case, the measures proposed in this publication for sealing the gap between the piston and the inner cylinder wall are completely

inadequate. In addition, the lubricator is only activated by setting the dispensing time with a staggered time interval at the desired time interval by electronic control, which is particularly disadvantageous if the lubricator is located in places that are difficult to access and hardly allow the dispensing time to be set. In addition, the design of the means for setting the dispensing time on the device is not very economical due to their frequent one-off use.

With the lubricator known from DE-U-92 14 096.3, there is no leakage problem due to the fact that the lubricant is housed in a lubricant pack, but the lubricant pack cannot be completely emptied because the piston has a stepped cross-section and the lubricant pack cannot, in principle, be completely emptied. As a result, residues always remain in the lubricant pack, meaning that only suboptimal use of the entire lubricant in the lubricant pack occurs. Furthermore, with the known lubricator, it is possible that these could cause explosions under unfavorable environmental conditions.

It is therefore an object of the present invention to avoid the disadvantages inherent in the prior art in a device for automatic lubricant dispensing with a piston arranged in a cylinder and a drive connected thereto.

According to the invention, this is achieved with a device for automatic lubricant dispensing according to claim 1. Advantageous further developments of the inventions are described in the subclaims.

It is very advantageous if the device according to the invention has a splash-proof switch that complies with the international standard ID 65. The splash-proofing is achieved by sealing the switch accordingly, which also makes the entire device for automatic lubricant dispensing explosion-proof. After the switch has been activated, the device can only be switched off by switching off the power supply. The preferred omission of a switch-off function is unproblematic because the automatic lubricator practically never has to be switched off, but remains in operation due to a preset lubricant dispensing quantity per day or other time unit until all the lubricant has been dispensed from the cylinder.

The switch is preferably designed as a cylindrical pin that interacts with a contact means designed as a snap-action contact disk. The snap-action contact disk is arranged on a circuit board together with the other electrical components for controlling the lubricant delivery. The snap-action contact disk has a convex cross-sectional shape similar to a dome as long as the device is not yet activated. The switch is located opposite the snap-action contact disk and is arranged in an opening in the housing wall of the device. If the switch designed as an activation pin is pressed into the housing, the front part of the activation pin or the switch presses the convex shape of the snap-action contact disk into a concave shape and the contact disk bent in this way, which is designed to be electrically conductive, simultaneously touches two contacts arranged below the contact disk, through which the device is started when contact is made.

The activation pin preferably has two circumferential projections that are spaced apart from one another at a distance corresponding to the wall thickness of the housing. When not activated, one of the projections is on the outside and the other projection is on the inside of the housing. When activated, the projection on the outside is pushed through the opening in the housing until the previously outside projection is on the inside and prevents the activation pin from moving back out of the housing. Sealing means that are arranged below the head of the activation pin are on the outside of the housing after the activation pin has been pushed in and seal the inside of the housing against the outside of the housing. Further sealing of the housing is achieved by the projection that is on the inside of the housing's inner wall.

Preferably, the switch is arranged in a recess in the housing of the device and thus does not protrude beyond the outer circumference of the lubricator when activated.

The invention is also based on the knowledge that a piston with a convex cross-section is very easy to manufacture and does not tend to open up the gap between the piston and the cylinder in the edge area either. Above all, however, the lines of the convex cross-section piston allow a sealing body to be accommodated, preferably in a one-piece sealing lip, which automatically presses against the cylinder inner wall when there is high pressure in the cylinder.

lation and the piston rim, thus ensuring a very good seal.

By adapting the cylinder head to the convex shape of the piston, complete drainage of the lubricant from the device is also ensured.

Furthermore, it is expedient if the device has a microprocessor and a memory connected to it and the device can be preset by means of these means to a certain quantity delivered per time, which can only be triggered by the switch.

In order to observe the emptying of the device according to the invention, the cylinder wall is at least partially made of a transparent material so that the silhouette of the piston or the sealing body can be seen from the outside. Along the main cylinder axis, a scale in the form of alphanumeric or abstract characters is also provided so that an accurate estimate of the emptying of the lubricant in the cylinder can be given. Such a display device is very simple to manufacture and read and is also very accurate. Especially when the cylinder wall is made of plastic, the transparency or translucency of the entire cylinder wall can be produced very easily.

To improve reading, it is useful if the upper edge of the piston or the sealing body is provided with a clearly visible color, e.g. signal color.

It may be useful to switch the system from winter to summer operation and to save the corresponding quantity/time presets in a non-volatile memory. The switchover can be triggered by another switch. This achieves the optimum lubricant supply by adapting to the usual outside temperatures in winter or summer.

An electric direct current or alternating current motor, as is often used in electrical engineering, can serve as the drive for the automatic lubricator.

However, the use of a stepper motor, which drives the piston inside the cylinder of the lubricator, is particularly advantageous. The advantage lies in the fact that a stepper motor can be controlled better for the purpose of the invention because it reacts with degree accuracy depending on electrical signals, e.g. a number of electrical pulses, and thus is more independent of temperature influences than is the case with DC motors, for example. The use of a stepper motor therefore allows an overall simpler control of the drive from a control board, which primarily has a pulse counter and a device that controls the step size of the motor depending on the electrical pulses present. In this way, the stepper motor can also be switched off when it has pushed the piston into the output area of the cylinder. This is done by specifying a number of stepper motor control pulses in a memory, and as soon as this number is reached, the stepper motor or the lubricator is switched off. Thus, the stepper motor shutdown device consists of a comparator or a control unit with a comparison program, which compares the number of pulses already set with the stored maximum number of pulses and, depending on this, forwards a control signal to the stepper motor and enables further movement of the stepper motor by a certain number of steps or switches it off.

A pulse/control signal generator can serve as a pulse generating device, which generates pulses depending on the time, e.g. 10 pulses per day or depending on the requirements of the machine unit to be lubricated, so that in machine-independent operation the stepper motor and thus the piston experiences a certain step deflection within a certain time unit and in machine-bound control the pulse generator generates the necessary number of pulses as required.

The invention is explained in more detail below using an exemplary embodiment. The drawing shows:

Fig. 1 shows a partial cross-section/partial plan view of a device according to the invention for automatic lubricant dispensing;

Fig. 2 is a cross-section through the device in Fig. 1 along the plane A-A; Fig. 3 is a partial section of Fig. 1 when not activated;

Fig. 4 shows a partial section of Fig. 1 when the device is activated;

Fig. 5 a special design of the drive as a telescopic spindle with driven gear in the non-extended and extended state;

Fig. 6 Representation view of a display;

Fig. 7 Block diagram of the electrical control of the lubricator; and

Fig. 8a Bottom view of a piston used for the lubricator according to the invention.

Fig. 8b is a side view of the piston 3 shown in Fig. 8a, but still without O-ring 58.

Fig. 8c Cross-sectional view of the piston according to Fig. 8b with the previously described stiffening elements 57, with a groove for the O-ring 58 and the sealing body 16 on the piston side as part of the piston 3.

Fig. 8d Cross section through the piston with the stiffening element 57 for centering the plate 10

Fig. 9 another schematic diagram of the lubricator in cross section Fig. 10 Cross section through the cylinder

Fig. 1 1a Cross section through the housing

Fig. 11b Cross section through the housing along the line D-D in Fig. 11a

Fig. 12a Top view of the cylinder

Fig. 12b Cross-sectional view according to 12a

Fig. 13 Stabilizer element

Fig. 1 shows an electrically operated automatic lubricant dispenser with an electric motor drive that drives a piston 3 via a feed rod 2 or a spindle. A battery 1 is used to supply energy to the drive. The type and design of the drive itself is comparable to the solutions disclosed in DE-PS-43 21 452 or DE-U-92 1 4 096. The piston 3 is located within a cylinder 4, which holds a lubricant 6 or another liquid or gaseous medium in its interior 5. An outlet 8 for dispensing the lubricant or the liquid medium is provided in the cylinder head area 7.

The piston has a convex shape 9 in cross-section, to which the shape of the cylinder in the cylinder head area 7 is adapted accordingly. At the rear, the piston has a spindle plate 10, which the spindle 2 engages to propel the piston. The spindle plate extends over a portion of the rear of the piston and is connected to the piston bottom 12 of the piston 3 via one or more webs 11 and is also centered via a centering element 104.

Between the edge 13 of the piston 3 and the inner cylinder wall 14 of the cylinder 4, a gap 15 is formed which enables the piston 3 to move within the cylinder 4. The gap is so small that the lubricant cannot pass through the gap. To improve the seal, a one-piece sealing lip 17 rests on the piston edge 13 above the gap 15 as a sealing body 16. The sealing lip 17 rises from the piston edge to the inner cylinder wall, so that when there is strong pressure in the interior 5 of the cylinder 4, the sealing lip 17 is pressed against the inner cylinder wall 14 and onto the piston 3.

While the piston is arranged in the cylinder, the means for driving the piston 3 are arranged in the housing 18 adjoining the cylinder 4, which encloses the cylinder in the overlap region 19.

The housing 18 and the cylinder 4 are detachably connected to one another, e.g. by a thread. This allows the empty cylinder to be separated from the housing and at the same time a filled cylinder to be locked from a housing 18 after the piston 3 has returned to its starting position. If the cylinder is permanently connected to the housing, it is possible, after removing a return movement lock, which prevents the piston from returning to its starting position when the automatic lubricator is in operation,

prevented by filling lubricant into the cylinder via the outlet opening 8 in order to refill the automatic lubricator and make it ready for operation.

It is also sensible to detachably connect the interior of the housing, i.e. drive and electrical parts, to it, so that after the lubricant has been used up, the cylinder and housing, preferably also the piston 3, can be separated from the drive and its electronic control parts and disposed of in a targeted manner, which is particularly easy if the housing 18, cylinder 4 and piston 3 are made of plastic and can therefore be recycled after the lubricant has been used up and the drive and its electronic control parts have been detached. The drive and its electronic control can then be reused to build a new lubricator, which is environmentally sensible and economically very advantageous due to the multiple use of the drive and its electronic control parts. This reduces the overall effort required to manufacture the automatic lubricator. In addition, according to the polluter pays principle, the disposal of the lubricator is left to the party who manufactures the lubricator, thereby reducing the disposal capacity of the user of the lubricator.

If the housing and cylinder are detachably connected, an empty cylinder can simply be replaced with a newly filled cylinder and the empty cylinder can then be recycled. The different principles and possibilities for recyclability of individual components of the automatic lubricator are described later.

Furthermore, the lubricator has a circuit board 20 in the housing 18, on which a microprocessor 54, designed for example as an ASIC, and memory as well as other control devices are arranged in order to control the drive of the piston accordingly.

The electronics are preset by storing the corresponding values so that the automatic lubricant dispenser dispenses a certain amount of lubricant, e.g. 2 or 4 g, per unit of time, e.g. per day. This preset dispensing is triggered by the on switch and can then only be stopped by switching off the supply voltage of a device arranged in the device.

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Battery. However, it is normally not necessary to shut it down and the lubricator will continue to operate until it is completely empty.

Fig. 2 shows a top view of the rear part of the lubricator. It can be seen that the switch 21, which is explained in more detail below, is located in a recess 22 of the circular-cylindrical housing 18 and thus does not protrude beyond the outer circumference 24 of the housing 18. The switch 21 is thus protected within the housing shape and does not offer any surface for objects protruding from the lubricator to attack.

Fig. 3 shows an enlarged section of the switch 21 and its interaction with a contact means 25 in the non-activated state. The switch consists of a cylindrical pin 26 which is inserted into an opening 27 of the housing 18. The pin has a pin head 28 whose diameter is larger than the diameter of the opening 27. A sealing ring 29 is arranged below the pin head. In addition, the cylindrical part of the pin 26 has two projections 30 and 31 which are bevelled in one direction and whose distance from one another corresponds to the wall thickness of the housing 18. The circumferential projections 30 and 31, whose diameter is larger than that of the opening 27, ensure that the pin 26 is pre-fixed in the housing wall. Due to its bevel, the pin 26 can be inserted into the housing 18 from the outside, but as soon as the second projection 31 has been pushed through the opening 27, the switch 21 can only be pulled out of the opening 27 with great force. In the interior of the housing, the switch 21 on the circuit board 20 is assigned a snap contact disk 23 as a contact means 25, which in the inactive state has a convex or dome-like curvature 32 of a metallic plate 33, below which there are two contacts 34, the conductive connection of which triggers the switching on of the device.

Fig. 4 shows the activation of the lubricator after pressing the pin 26 into the housing 18. The front part 35 of the activation pin pushes the curved part 32 of the snap contact disk 25 down so far that the snap contact disk simultaneously touches the contacts 34 lying beneath it and thus creates an electrical connection between the two contacts 34. If the pin 26 is then removed, the contact remains and thus when the lubricator is switched on or, in an alternative embodiment, the snap contact disk is returned to its position shown in Fig. 3.

It can be moved back to its original position, thus decoupling the electrical parts for the drive of the automatic lubricator from the power supply.

It can also be seen that the second projection 30 of the pin 26 is located inside the housing 18 and prevents the switch 21 from being pulled out. At the same time, it also seals the interior of the lubricator from the outside and from the inside against the outside of the lubricator. The seal 29, which is pressed between the pin head 28 and the outer wall of the housing 18, provides further sealing. The sealing measures shown provide protection against splash water and explosions, since the interior of the housing is sealed against external influences and the exterior of the housing is shielded against interference, e.g. sparks or electrical flashovers. Such protection is particularly necessary when such a lubricator is used in a mine, where the triggering of explosions must be prevented at all costs.

Fig. 5 shows in Fig. 5a a single or multi-stage telescopic spindle with driven gear in the non-extended state, while in Fig. 5b the telescopic spindle is extended to the maximum stop. The use of a telescopic spindle to drive the piston results in a large space saving and also represents a very precise means of driving the piston forward because even the smallest changes in length can be adjusted with a telescopic spindle.

In order to avoid exposing the lubricant in the cylinder to excessive pressure due to the continued advance of the piston due to reduced lubricant consumption, e.g. when the unit to be lubricated is switched off, it has proven to be very advantageous to provide a pressure sensor 36 coupled to the microprocessor which switches the device off when a certain pressure in the cylinder is exceeded until the pressure has fallen below a predetermined value. Such a pressure sensor 36 can be used inside the cylinder 4 as shown, but also in the rear area of the housing 18 if the pressure sensor can measure the force acting on the piston. Preferably, the pressure sensor 36 is arranged on the apex of the piston 3 so that it can extend into the outlet area 8 of the cylinder when the piston advances in order to press even the last remnants of the lubricant out of the outlet area.

To read the piston propulsion, the entire cylinder or just a part of it is made transparent. This is particularly easy to achieve if the cylinder is made of plastic or glass.

When the piston is driven forward, the observer can see the piston edge or the sealing lip through the transparent cylinder housing and thus make an estimate of the previous lubricant use.

For a more precise determination, it has proven to be very advantageous if the cylinder has a scale in the form of alphanumeric characters or abstract characters such as simple lines in the transparent area along its main axis. In this case, it can be very advantageous if the distance between the scale characters corresponds to a certain amount of lubricant released and a corresponding assignment of the amount of lubricant released to the distance between the scale characters is documented on the housing. This allows the observer to very quickly determine the amount of lubricant released or make a statement about the amount of lubricant still present. The smaller the distance between the scale characters, the more accurate the estimate.

Since the lubricant delivery is dispensed in stages when the lubricant delivery is preset to e.g. 4 g per day, the delivery display is particularly accurate if a scaling symbol is assigned to the set delivery quantity per unit of time.

To improve the reading of the output, it is useful if the piston edge 13 or the sealing lip 17 is provided with a striking color design, so that a very visible difference is created between the piston edge 13 and the transparent material. To make the reading faster, it may also be useful to provide each scale symbol with a consecutive number, which makes counting easier.

A replaceable battery or accumulator can be used to supply the lubricant dispenser with power, as can a mains-dependent power supply.

Instead of using a spindle, it is of course also possible to drive the piston using a worm gear, which normally requires a considerably

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higher efficiency than a spindle, but sometimes requires a little more space.

By presetting the dosage, the adjustment devices for regulating the dosage amount that have always been required for lubricants can be dispensed with, which simplifies the entire structure of the lubricator and enables more reliable dispensing.

It is practical and advantageous to use a stepper motor 55 as the drive, which drives the spindle 2 or the piston 3 depending on the electrical pulses or signals supplied. For this purpose, a pulse/control signal generator 53 is provided on the circuit board 20, which generates a certain number of electrical pulses/control signals within a certain time unit and feeds these signals to a control and evaluation unit 54 of the stepper motor 55 - Fig. 7 -. This achieves a control or drive that is independent of external influences and, above all, in principle avoids the disadvantages of temperature dependence, which is regularly present in direct current drives. The lubricator or the stepper motor can also be switched off in this way by providing a counter evaluation unit in the control evaluation unit 54, which counts the control pulses delivered to the stepper motor, stores them in a volatile RAM memory, and compares them with a specified "maximum pulse number" value, which is stored in a non-volatile ROM memory. The "maximum pulse number" corresponds to the maximum propulsion of the piston 3 in the cylinder when the piston touches the inner cylinder wall in the cylinder head area 7. The evaluation unit then compares the number of control pulses delivered with the "maximum pulse number" value, and the control unit 54 then switches the stepper motor off when the number of counted control pulses corresponds to the number of stored "maximum pulse number". If the number of control pulses counted is below the "maximum number of pulses", the spindle or piston is allowed to advance by the step size corresponding to the control pulse delivered.

The lubricant dispensing is switched on as described above by means of the switch 21, which is connected to the control unit.

If the lubricator is provided with or connected to a corresponding display unit 50 in the form of a display as shown in Fig. 6, the number of counting pulses emitted and thus a measure of emitted

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The amount of lubricant or a measure of the remaining amount of lubricant can be displayed there, either in absolute numbers (e.g. 1225), or as a percentage (e.g. 12.5%) and/or in relation to the total number (1225/5000), so that the user of the lubricator can always obtain very precise information about the piston deflection and the amount of lubricant dispensed or still remaining in the lubricator.

The display can also be made in such a way that the display 50 has two different types of alphanumeric or abstract characters, namely a first group of characters consisting of a number of first characters 51, whereby the number of first characters is proportional to the number of control pulses delivered to the stepper motor, and a second group of characters consisting of a second number of characters, whereby the number of first and second characters is proportional to the number of total possible control pulses and is therefore a measure of the total amount of lubricant. Such an incremental display, especially with a stepper motor as an incremental drive, is very simple and precise with regard to the absolute display of absolute and very fine changes in the amount of lubricant delivered or the amount of remaining lubricant.

Instead of a pressure sensor, a current consumption monitoring device can be provided for the final shutdown of the stepper motor, which switches off the electronics and thus the lubricator as soon as a pre-programmed maximum current consumption value of the motor is exceeded.

In the case of machine-dependent control, i.e. when the machine unit to be lubricated sends control signals to the lubricator according to its lubricant requirements, the display allows a very precise indication of the amount of lubricant delivered in absolute numbers, i.e. in ml per unit of time, from which the machine maintenance personnel also receive further information about the condition and wear of the machine to be lubricated. This may make it easier to make decisions about whether to continue operating the machine unit to be lubricated or to replace certain units that are about to fail.

In order to be able to control the amount of lubricant delivered by a DC motor, it can also be provided that a metal projection in the form of a pin is located on a gear wheel of the transmission and is connected to

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this gearwheel rotates. With each rotation of the said gearwheel, the path of this pin leads past a diode or other detection means, which triggers a signal pulse. This signal is recorded by the microprocessor 54 located on the circuit board and fed to a counter, which counts the signals triggered by the diode. If the number of signals counted by the counter reaches a certain value, which corresponds to a value at which the lubricant medium is completely pushed out or the piston has its maximum propulsion, the microprocessor switches off the drive system.

The machine-dependent control of the automatic lubricator is designed to activate or deactivate the lubricator without contact using a magnetic switch. For this purpose, a magnetic switch is mounted on the circuit board 20 so that it is as close as possible to the wall of the housing cover. A coil is also mounted on the housing cover which, when current flows, switches the magnetic switch inside the housing and activates or deactivates the drive. If there is no voltage on the coil, the drive system is deactivated. If the coil is live, the drive system is activated. The voltage signals fed to the coil are supplied by the machine unit to be lubricated and the contactless control of the drive allows the mechanical decoupling between live cables outside the housing from the inside of the housing and thus automatically avoids possible flashover voltages. This ensures effective explosion and water protection for the automatic lubricator.

The coil, preferably cast in plastic with an iron core, is designed in such a way that it can be pressed into a recess in the housing provided for this purpose with a simple movement of the hand and thus lies within the contour of the housing, similar to pin 21. By encapsulating the interior of the lubricator from the exterior as described above, a very effective and cost-effective explosion and splash protection of the automatic lubricator is achieved.

If the automatic lubricator is completely empty, there are two basic alternatives for continuing to use the automatic lubricator. On the other hand, it is therefore advantageous to only replace the components that are subject to heavy loads and can be replaced inexpensively. This includes, for example, the cylinder, the housing 18 and the piston 5, which

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detachable connection with the drive and the electronic control parts, e.g. the circuit board 20, can be separated from it after the lubricant has been drained and sent for targeted plastic recycling.

If the housing and cylinder are detachably connected to one another, this connection should only be able to be broken using a suitable special tool in order to avoid the improper separation of the housing and cylinder with the corresponding consequences.

Furthermore, if the entire interior of the housing, in particular the drive and the electronic control components, is designed to be detachable from the housing, it can also be advantageous if the snap contact disk can be moved back into its original shape as shown in Fig. 3 after the activation pin has been removed by means of appropriate measures. Alternatively, the pressed-in snap contact disk can also be replaced by a snap contact disk that has not yet been pressed in by inserting a new snap contact disk into a corresponding socket on the circuit board 20.

When the internal components of the automatic lubricator are reused as described above, plastic parts of the cylinder and housing are disposed of or recycled and are thus automatically separated from the electrical metal parts of the drive system. This modular design has great advantages when manufacturing the lubricator.

Another alternative to restarting the automatic lubricator is to provide a switchable reverse lock for the piston, which allows the piston to move to its original starting position when the cylinder is refilled. The cylinder can then be filled by pouring lubricant into the cylinder via the outlet opening 8, whereby the piston is simultaneously forced back to its starting position when the cylinder is filled.

Depending on the area of application and location, one or the other alternative is advantageous for recycling and refilling the automatic lubricator.

Fig. 8a shows the bottom view of a piston 3 with corresponding bracing and stiffening elements 57 to prevent deformation of the piston during commissioning.

1 me. In view of the fact that the pressure in the lubricant chamber can be 4 bar and more, such stiffening elements 57 are useful. Furthermore, the piston is equipped with an O-ring 58 to ensure a good seal between the cylinder interior and the cylinder wall.

Fig. 8b shows a side view of the piston 3 with a groove 59 for the O-ring 58.

Fig. 8c shows an enlarged cross-sectional view of the piston according to Fig. 8b, with the previously described stiffening elements 57, the groove 59 for the O-ring 58 and the sealing bodies 16 on the piston side as part of the piston. The sealing bodies seal the cylinder chamber from the housing.

Fig. 8d shows once again an overall cross-section through the piston with the stiffening element 57 for centering the plate 10.

The motor for driving the piston is, as already described, preferably a DC motor 90, which is controlled by electronics. The rotation of the motor shaft (not shown) is reduced by the gear 91, which is preferably designed as a gear transmission, e.g. in a ratio of 1:6221. The lubricant dispensing device is supplied with energy by the battery 1, whereby the batteries preferably consist of three alkaline mignon cells - Fig. 1la, which are packed next to each other in a stocking tube, connected in series and completely wired with a plug contact. During assembly, the plug only has to be inserted into the socket on the electronics (not shown).

The rotation of the engine is converted into a linear movement of the piston as follows:

There is a threaded bushing in the last gear of the gear box. In this threaded bushing there is a threaded or feed rod 2 that is secured against rotation. If the last gear rotates by activating the motor 90, the threaded rod is unscrewed. The pitch of the thread is very low and is preferably 0.5 mm. If the motor rotates 6221 times, the last gear has made a complete revolution and the feed or feed rod 2 has been rotated.

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Threaded rod 2 and thus also piston 3 have travelled a distance of 0.5 mm. Furthermore, a poorly reflecting area is attached to the first driven gear of the gear 91.

The electronics include buttons, two sockets - 2-pin for battery, 6-pin for motor and sensor -, a microprocessor, a time quartz and various resistors. These parts are SMD-equipped.

i How the electronics work ^:

On the first driven gear is the already mentioned bad ^!

reflective area, e.g. a black, matte plastic sticker, which reflects significantly less than the brass of the gear. An optical infrared sensor is mounted in the gear plate above the gear. This sensor consists of a transmitter and a receiver. The electronics are now given exactly how often a signal must come from the sensor in order to complete the entire travel path. The system then switches off promptly after the preset running time.

Tests have been carried out to determine how long it takes at 4 bar internal cylinder pressure to receive X-signals from the sensor. This describes the "worst case". If the X-signals are not detected within this specified time, the system switches off, as there must either be a technical defect (engine, battery, transmission or sensor) or the pressure of 4 bar has been exceeded (engine speed decreases).

This is an advantage because the speed can change during operation or will change due to temperature or battery voltage influences; however, it is guaranteed that the same amount of lubricant is always pressed out of the cylinder.

Two resistors are mounted on the electronics to preset the running times. Since there are four positions where these resistors can be mounted, there are four different options that mean four different running times, e.g. 1, 3, 6, or 12 months.

The control device is specified that lubrication should take place approximately every 6 hours during 12-month operation in order to ensure that lubrication points are supplied even during single-shift operation. With a 12-month dispenser, pressure is therefore built up in the cylinder every 6 hours. Since the duration of the pressure build-up is always the same, the different running times only differ in that the break between dispensing is different. A 6-month dispenser therefore starts every 3 hours, a 3-month dispenser every 90 minutes, a 1-month dispenser every 30 minutes. This is advantageous because with short running times it is important that the pulses come as close to one another as possible in order to get as close as possible to a permanent pressure build-up. With long running times this is of secondary importance.

The activation pin is pre-pressed into the cover as previously described. If the user pushes this activation pin all the way into the housing of the lubricant dispenser, the system is activated.

The user is informed of which presetting is programmed into the lubricator to be used by marking the activation pin, e.g. by means of a colour marking.

After activation, the sensor is first automatically adjusted. Since the electronics are given a time limit for X signals to come from the sensor, the intensity of the sensor is changed until the receiver has received this signal optimally. This is done by having 16 different settings for the sensor current, which also means a change in the brightness of the transmitter. If the intensity of the transmitter is too high, the black sticker may reflect the infrared beam. If the intensity is too low, the brass of the gear may not reflect it either. This automatic adjustment of the sensor takes about 4 seconds. If the specified number of signals is not detected during this time, the system runs for another 4 seconds without adjusting itself again. If the system switches off after 4 seconds, the sensor is working optimally and the system is OK. However, if the system does not run at all or runs for 8 seconds, there is a defect.

According to the teaching of DE-A-4321 552, the lubricant quantity is influenced by a predefined setting of the duration of the lubricant delivery. This is an open-loop control. In the lubricant dispenser described according to the invention, however, the lubricant quantity is controlled directly and

not monitored over a period of time. To do this, the volume of lubricant delivered is measured using the electronics described above and the lubricant supply is stopped after a specified volume has been delivered - this corresponds to the corresponding feed path. The volume of the lubricant delivered is therefore measured using the number of motor revolutions or signal pulses. This is a closed control loop that differs significantly from the open-loop control DE-A-4321552.

Fig. 9 shows a further schematic diagram of the lubricant dispensing device according to the invention with batteries 1 for power supply, a feed rod 2 which is driven by a motor 90 and in which a gear 91, preferably a reduction gear, is arranged between the feed rod 2 and the motor 90. The feed rod is connected to the piston 3, which is arranged inside a cylinder 4 with a transparent cylinder wall with the previously described integrated scale. In the cylinder there is lubricant 6, which can be dispensed via a dispensing opening 8. In the not yet ready-to-use state after the manufacture of the lubricant dispenser, the dispensing opening 8 is provided with a closure cap 92 which is connected in one piece to the cylinder wall or the dispensing opening 8. Before the lubricant dispenser is used, the closure cap 92 must be separated, e.g. by cutting. Furthermore, the delivery area of the cylinder is provided with an external thread 93 on the outside in order to be screwed into a lubrication point with a corresponding internal thread.

Furthermore, the previously described switch 21 as well as the circuit board 20 opposite this switch 21 with the control electronics located thereon are indicated.

Preferably, the outer circumference of the closure cap 92 extends beyond the external thread 93, so that screwing the external thread into a lubrication point is only possible after the closure cap has been removed. Such an embodiment is shown in Figs. 10, 12a and 12b. Fig. 10 also shows a thread 100, which is used for screwing to a corresponding counter-thread of the housing - see Fig. 11a. Preferably, the cylinder can no longer be detached from the housing after it has been screwed to it. A border 101 facing away from the cylinder wall serves to better seal and fix the screw cap.

Fig. 11a shows a further embodiment of the housing part 18 of the lubricant dispensing device, in which batteries 1, the control electronics board 20 and the other drive parts are housed. As shown, the control board 20 lies in a guide 95 for mechanical stabilization of the board. The guide 95 preferably consists of a groove 96 formed in the housing 18. Furthermore, an internal thread 110 can be seen on the connection to the cylinder with the lubricant, which can be connected to the external thread 100 - see Fig. 10 - of the cylinder 4. Another representation of the housing 18 is shown in Fig. 11b, but from a perspective rotated by 90 degrees.

Fig. 1 2a shows a further top view of the cylinder of the lubricant dispenser with applied scale marks so that the user can see the fill level of the lubricant dispenser.

Fig. 12b once again shows that the closure cap 92 has a larger external diameter than the external thread 93, so that screwing the external thread into a lubrication point is only possible after first removing the closure cap 92, which is integrally connected to the output area of the lubricator.

Fig. 1 3 shows a stabilizer element 102 with an opening 103, which is provided with an internal thread 104 for receiving the lubricator with its external thread 93. The stabilizer element can be screwed onto an external thread of a lubrication point and can accommodate the lubricant dispensing device on the other side. The contour adaptation of the stabilizer element 102 to the outer edge of the lubricator enables a form-fitting connection of the stabilizer element. The stabilizer element can prevent the thread 93 from breaking away, especially in the event of strong vibrations.

If the stabilizer element consists of an elastic medium, the lubricant dispensing device can also be screwed directly to the lubrication point and the stabilizer element is then compressed, thus ensuring a stable position of the lubricant dispensing device to the lubrication point.

From what has been written above, it is immediately clear to the expert that each of the measures such as the design of the piston, the seal between the piston and the cylinder, the means for switching on the automatic

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see the lubricator, the readability of the piston propulsion, the means for determining the pressure in the cylinder, etc. improve the automatic lubricators known from the state of the art, and that the individual measures can also be implemented independently of the other measures without being inventive.

Claims (18)

Expectations 1. Device for automatic lubricant dispensing with a Cylinder (4) arranged piston (3) and an electric motor drive means (1) connected thereto and a switch (21) providing protection against splash water and/or explosions, which is arranged in an opening (27) of the housing of the device, whose contour, when switched on, lies within the outer contour of the lubricant dispensing device,
which is associated with a contact means (25), which, when activated, connects at least two contacts (34) of the contact means to each other, which has sealing means (29) which prevent media from entering or escaping into or from the device; with a cylinder wall which consists at least partially of transparent material ; wherein the piston and/or the sealing body associated with the piston are at least partially provided with a clearly visible color that supports the readability of the piston position in the cylinder; wherein the cylinder (4) and the housing are detachably connected to one another; wherein the device has a dispensing area (6) with a dispensing opening (8) which can be closed by a cap, wherein the dispensing area is provided on the outside with a thread (95) and that the closure cap (92) has a larger outer diameter than the thread (93); wherein the piston (3) is provided with a convex shape in cross section, the convex shape of the piston is adapted to the shape of the inner wall of the cylinder head; wherein the drive means (1) is a stepper motor which drives the piston via a spindle; wherein the stepper motor is battery powered; wherein a sealing body (16) is provided on the piston rim of the piston (3); wherein the drive means (1) for driving the piston (3) are arranged in the housing (18) adjoining the cylinder (4); wherein the housing (18) encloses the cylinder (4) in an overlap region (19); wherein the housing (18) and the cylinder (4) are detachably connected to one another by a thread; the housing (18), the cylinder (4) and the piston (3) are made of plastic. 2. Device according to one of the preceding claims, characterized in that the switch (21) is arranged in an opening (27) of the housing (18) of the device and is cylindrical and has two circumferential projections (30, 31) whose distance from one another corresponds approximately to the wall thickness of the housing (18) and that the second of the projections (30) can be pushed through the opening (27) in which the switch (21) is inserted. 3. Device according to claim 2, characterized in that the on switch (21) has no switch-off function. 4. Device according to one of the preceding claims, characterized in that the switch (21) is arranged in a recess (22) of the housing (18) of the device and, when activated, does not protrude beyond the outer circumference of the lubricant dispensing device. 5. Device according to one of claims 2 to 4, characterized in that the contact means (25) is a snap contact disk (23) which, in the activated state, has a convex conductive plate (33) which is pressed into a concave shape when the switch is activated and the plate (33) thus formed touches two adjacent contacts simultaneously. - 24 - 6. Device according to one of the preceding claims, characterized in that the device has a microprocessor (54) and a memory (RAM, ROM) connected thereto, the microprocessor being preset to a certain quantity dispensed per time, which can be triggered by the switch (21). 7. Device according to claims 5 and 6, characterized in that the snap contact disk (23) is arranged on a circuit board (20) together with the control unit (54) or the microprocessor. 8. Device according to one of claims 6 or 7, characterized in that the microprocessor has a signal input, via which control signals for switching on the lubricant delivery from the unit to be lubricated can be supplied. 9. Device according to one of the preceding claims, characterized in that the device can be switched from winter to summer operation and the corresponding quantities/time/presets are stored in a non-volatile memory (ROM). 10. Device according to one of the preceding claims, characterized in that the electromotive drive can be controlled by means of a control signal from a control signal generator (53), in particular can be controlled incrementally. 11. Device according to claim 10, characterized in that the electric motor drive (55) is connected to a control unit (54) which receives a control signal from the control signal generator (53) and that compares the number of control signals delivered to the electric motor drive with the number of maximum possible step signals or rotation signals of the electric motor drive and in the event that the number of control signals delivered to the electric motor drive is at least as large as a predetermined number of control signals, the electric motor drive (55) is switched off. 12. Device according to one of the preceding claims, characterized in that the lubricant dispensing device comprises a display unit (50) which is connected to the control unit (54) and from there a numerical Information and/or symbolic measurement information about the number of control pulses delivered to the electric motor drive and/or the maximum number of control pulses to be delivered. 13. Device according to one of the preceding claims, characterized in that means are provided for the direct or indirect detection of the propulsion of the piston and/or the movement of the electric motor drive, that the detection means generates signal pulses during the propulsion of the piston or during the operation of the drive, which can be fed to a counting device, and that comparison means are provided which compare the number of counted signal pulses with a predetermined, stored value. 14. Device according to claim 13, characterized in that the comparison means is part of a control-evaluation unit (54) which switches on the drive when the number of counted signal pulses reaches the predetermined value. 15. Device according to one of the preceding claims, characterized in that the cylinder (4) and the housing (3) can only be separated from one another by means of a special tool. 16. Device according to one of the preceding claims, characterized in that the lubricant dispensing device has means for contactless activation/deactivation of the control or the drive. 17. Device according to claim 16, characterized in that the means for contactless activation/deactivation of the lubricant dispensing device consists of a magnetic switch on the one hand, which is arranged inside the housing (1 8) of the lubricant dispensing device and of a unit which excites the magnetic switch, e.g. a coil, on the other hand, which is arranged outside the housing of the lubricant dispensing device. 18. Device according to claim 17, characterized in that the excitation unit of the magnetic switch is located within the outer contour of the housing (18) and is electromagnetically coupled to the unit to be lubricated.