Detection device and lubricant distributor

Abstract

Detection device (101; 601; 701; 801; 901) for a piston movement of a lubricant distributor (301; 401), comprising the following features: - a movable actuating element (111) with a magnetic device (113), wherein the magnetic device (113) of the actuating element (111) is designed as a cylindrical permanent magnet, - a movable magnetic element (137), wherein the magnetic element (137) is designed as a ring-shaped permanent magnet (137) and is arranged axially spaced from the actuating element (111), - wherein the actuating element (111) is designed such that it can be moved from an initial position to an end position by a movement of the piston (307; 407) in the direction of the actuating element (111), - wherein the magnetic device (111) and the magnetic element (137) are designed and arranged such that a repulsive magnetic force exists between them, by which, when the actuating element (111) is moved from the initial position towards the end position, the magnetic element (137) is movable from a basic position to a holding position, such that when the magnetic device (113) is in the initial position and when the magnetic element (137) is in the basic position, such a magnetic force acts between them that the magnetic element (137) is not displaceable, and such that when the actuating element (111) is moved from the initial position towards the end position, such a large repulsive magnetic force can be exerted by the magnetic device (113) on the magnetic element (137) that the magnetic element (137) is displaceable.

Description

[0001] The invention relates to a detection device for a piston movement of a lubricant distributor and a corresponding lubricant distributor.

[0002] Lubricant distributors are well known, as disclosed, for example, in US 3,651,827 A or DE 20 2006 016 377 U1. They serve to dispense a metered amount of lubricant to one or more lubrication points. They are often constructed as a single unit and are designed to dispense various metering volumes, with each lubricant distributor having, for example, one or two threaded holes on each of its two end faces for the optional connection of one or two main lines of a central lubrication system. The lubricant distributor has, for example, eight threaded holes for connecting the lines to the lubrication points. The lubricant metering itself is achieved by a metering piston, which is movably arranged in a cylinder bore within the lubricant distributor housing. A defined quantity of lubricant is dispensed with each stroke of the metering piston. A control piston is usually provided for controlling the metering piston.The control piston opens and closes the main lines. Depending on the pressure applied, the control piston moves in one direction or the other, which in turn moves the metering piston and dispenses a corresponding amount of lubricant.

[0003] In addition to these single-line or two-line distributors, the same applies of course to other designs, for example in the case of a progressive distributor, in which several pistons deliver lubricant to several lubrication points in a corresponding manner.

[0004] For proper operation, it may be necessary to monitor the movement of the metering piston and / or the control piston, i.e., to determine whether the metering piston is performing its intended metering stroke. Numerous methods for this are already known, but these are generally technically complex and therefore expensive. A comparatively simple device for monitoring the movement of the metering piston, however, comprises a sleeve with a bore at one end, in which a pin is held. The pin is connected to the metering piston and thus follows its movement. The length of the pin is chosen so that it protrudes visibly from the sleeve, thus making the position of the piston visible from the outside. Since high pressures of several hundred bar can prevail inside the lubricant distributor, a seal between the sleeve and the pin is required. This seal must meet stringent requirements for tightness.However, due to the inevitable wear and tear on the seal caused by the pin's movement, reliable sealing can no longer be guaranteed after a certain period of use. Furthermore, a control pin negatively impacts the internal pressure balance and the displaced stroke volume, often resulting in inaccurate lubricant application.

[0005] It is therefore an object of the present invention to provide a detection device for the piston of a lubricant distributor that is simple and robust and thus not susceptible to wear. It is a further object of the invention to provide a corresponding lubricant distributor.

[0006] This problem is solved by a preferred embodiment of the invention. Accordingly, a detection device with the following features is specified: - a movable actuating element with a magnetic device, wherein the magnetic device of the actuating element is designed as a cylindrical permanent magnet, - a movable magnetic element, wherein the magnetic element is designed as a ring-shaped permanent magnet and is arranged axially spaced from the actuating element, - wherein the actuating element is designed such that it can be moved from an initial position to an end position by a movement of the piston in the direction of the actuating element, - wherein the magnetic device and the magnetic element are designed and arranged such that a repulsive magnetic force exists between them, by which, when the actuating element is moved from the initial position towards the end position, the magnetic element is movable from a basic position to a holding position, such that when the magnetic device and the magnetic element are in the initial position, a magnetic force acts between them such that the magnetic element is not displaceable, and such that when the actuating element is moved from the initial position towards the end position, a repulsive magnetic force of such a large magnitude can be exerted by the magnetic device on the magnetic element that the magnetic element is displaceable.

[0007] The invention is essentially based on the understanding that continuous monitoring, for example by complex electronic detectors, is not necessary for a large number of lubricant distributors or pistons of a pump. Instead, it is sufficient to check at regular intervals whether at least one lubrication process has taken place since the last inspection. This can be done, for example, by a maintenance technician or service personnel who visually inspects the lubricant distributor at regular intervals, such as every 15-30 minutes. It is quite possible for several hours to pass between two individual lubrication processes and the associated piston movements. This is particularly true when using grease. The lubrication process itself, and thus the movement of the piston, only lasts a few seconds.It would therefore be pure chance if a maintenance technician could directly observe the actual lubrication process during a visual inspection. Simple devices for visualizing piston movement, such as the pin described earlier, prove to be disadvantageous here, as they follow the piston movement and thus return to their starting position after the lubrication process. During the next visual inspection, the maintenance technician cannot determine whether one or more lubrication processes have taken place since the last inspection.

[0008] The invention reliably enables this. As soon as the piston begins to move during a lubrication process, the actuating element is moved towards its end position. The magnetic device moves the magnetic element towards the holding position through the acting magnetic force. However, when the piston moves back, at least the magnetic element remains in its end position, so that the lubrication process is indicated by the position of the magnetic element even after it has finished. Even with a permanent coupling of the actuating element to the metering piston, which is not strictly necessary, the magnetic element would remain in its end position, since the movement occurs due to a repulsive magnetic force; therefore, the magnetic element is not carried along when the actuating element moves back to its initial position.

[0009] During the next visual inspection, the maintenance technician can easily determine, based on the magnetic element being in its holding position, that at least one lubrication cycle has taken place and the lubricant distributor is therefore functioning correctly. Because the piston movement is indirectly transmitted to the magnetic element via magnetic forces, the moving parts can be easily separated structurally, eliminating the need for wear-prone dynamic seals. The actuating element can thus be located within a housing of the detection device, while the magnetic element is movably mounted outside the housing. Both elements are then separated by a housing wall. The housing can also be multi-stage, with the magnetic device and the magnetic element located in separate cavities. It is only necessary to ensure that the magnetic forces are not excessively shielded or impaired.

[0010] In a preferred embodiment of the invention, the detection device has a holding element designed such that a holding force can be exerted on the magnetic element in the holding position. This holding force ensures that even in the event of vibrations or shocks, the magnetic element does not unintentionally return to its home position, thus preventing a false negative reading during visual inspection. The detection device therefore operates with extreme reliability.

[0011] In a preferred embodiment of the invention, the actuating element is designed such that it is only intermittently engaged with the piston. It is neither necessary nor detrimental to the functionality of the invention for the actuating element to be permanently engaged with the piston. Continuous monitoring of the piston movement is not performed. For example, during a visual inspection, it is sufficient for the maintenance technician to reset the actuating element and the magnetic element to their initial or home position, so that the next lubrication process can be indicated from that point onward.

[0012] In a preferred embodiment of the invention, the actuating element comprises a pin element which, in the installed state, is arranged on the actuating element pointing towards the piston and whose length is selected such that the piston can exert a force displacing the pin element only at one end of its movement. This achieves, in a structurally simple manner, that the piston is only in operative engagement with the pin element and the actuating element temporarily. During movement, the piston presses against the pin element and thus displaces the actuating element. During the return movement, however, the piston simply retracts from the actuating element without moving it back. In principle, the pin element could also be provided with a corresponding thread and screwed into a mating thread in the piston, thus following the movement of the piston without departing from the scope of the principle of the invention.However, there is no need for such design modifications. Furthermore, such a detection device can be easily retrofitted to existing lubricant distributors, as the piston does not require any special features. The length of the pin element can be selected or adjusted according to the piston's range of motion. For connection to a housing, for example, the detection device can have an external thread, which is screwed into a corresponding internal thread at the end of the piston bore. If necessary, an adapter sleeve can be used, which has an external thread matching the internal thread and an internal thread matching the external thread of the detection device.

[0013] As mentioned above, the detection device also has the following features: - the magnetic device of the actuating element is designed as a cylindrical permanent magnet, - the magnetic element is designed as a ring-shaped permanent magnet, - the magnetic device and the magnetic element are arranged in such a way that when the magnetic device is in the initial position and the magnetic element is in the home position, no magnetic force acts between them, - the magnetic device and the magnetic element are aligned in such a way that when the actuating element moves from the initial position towards the final position, a repulsive magnetic force can be exerted from the magnetic device onto the magnetic element.

[0014] The term "no magnetic force" means that the prevailing magnetic force is so small that it does not displace the magnetic element at the specified relative position of the magnetic device and the magnetic element. This can be achieved, for example, by axial spacing. This design is particularly easy to manufacture and extremely resistant to wear. The magnetic forces ensure reliable visualization of the piston movement, while guaranteeing that the magnetic element is not moved towards the retaining element without a movement of the piston. Otherwise, this would result in a false detection and would not reliably indicate the functionality of the lubricant distributor.

[0015] In a preferred embodiment of the invention, the holding element consists at least partially of a magnetizable material. This ensures in a simple way that no attractive force occurs between the magnetic element and the holding element when the magnetic element is in its home position. As the permanent magnet element approaches the holding position, the holding element is magnetized by it, thus generating the holding force. As soon as the magnetic element is moved away from the holding position, the magnetization of the holding element is lost and the holding force disappears. The holding element is accordingly made of a magnetically "soft" material. Alternatively, the holding element can also consist of a permanent magnet that is aligned with the magnetic element and generally exerts an attractive force. However, the strength of the permanent magnet is dependent on the magnetic strength of the holding element.The distance between the base position of the magnetic element and the holding element is chosen such that the magnetic force acting in this position is so small that the magnetic element is not moved away from the base position.

[0016] In a preferred embodiment of the invention, the detection device has a return element by means of which the magnetic element can be moved from the holding position to the home position by overcoming the holding force. This allows a maintenance technician to easily push the magnetic element back into the home position after a successful visual inspection, so that the next lubrication process can be detected.

[0017] In a preferred embodiment of the invention, the retaining element is designed as a spring element, which is arranged between a housing of the detection device and the return element. This has the advantage that the return element can be brought back to its initial position by means of the spring element.

[0018] In a preferred embodiment of the invention, the return element is designed as a movable cap element that covers the magnetic element and is transparent in the area of ​​the magnetic element. The cap element allows for easy visual inspection due to its transparency. It also provides protection for the magnetic element.

[0019] In a preferred embodiment of the invention, a force element is further provided by means of which the actuating element can be moved from the end position to the initial position. The force element is preferably designed as a spring element which, upon the piston's return movement, moves the actuating element, but not the magnetic element, back to the initial position. Manual retraction of the actuating element is thus eliminated.

[0020] The problem is further solved by a lubricant distributor comprising a housing block and at least one piston guided in a piston bore, including at least one detection device according to any one of claims 1 to 9. With such a lubricant distributor, the lubrication processes can be monitored in a simple and reliable manner. The lubricant distributor can be designed, for example, as a single-line distributor, a two-line distributor, a throttle distributor or flow limiter, a delivery piston of a pump element, or as a progressive distributor.

[0021] The lubricant distributor is designed for the delivery of lubricant to at least one lubrication point, wherein the lubricant distributor has a housing block in which at least one piston is arranged to be movable back and forth in at least one cylinder bore, wherein a detector unit is provided with which the position of the piston in a piston position can be detected, wherein the detector unit is arranged on the housing block in such a way that the piston can come into operative contact with the actuating element when it is in the cylinder bore near one of its end positions.

[0022] Further advantages, features, and details of the invention will become apparent from the exemplary embodiments of the invention described below with reference to the figures. These figures show: Fig. 1 a state-of-the-art detector device, Fig. 2 a detector device according to a preferred embodiment of the invention, Fig. 3 an inlet distributor with a detector device according to Fig. 2, Fig. 4 a progressive distributor with a detector device according to Fig. 2, Fig. 5 and Fig. 6 the detector device after Fig. 2 in different operating states, Fig. 7 to 10 different designs of a retaining element.

[0023] In the Fig. Figure 1 is a lubricant distributor 1 in the form of a so-called inlet distributor of a known design. The lubricant distributor 1 is equipped with a display unit 3 according to the prior art. The lubricant distributor 1 comprises a housing 5 in which a cylindrical bore 7 is provided. A metering piston 9 is arranged to be horizontally movable within the cylindrical bore 7. The cylindrical bore 7 includes two expanding bores 11 and 11' at its ends, each having an internal thread. The bore 11 is closed with a plug 13 that is screwed into the internal thread. In the embodiment shown here, the housing 5 has two lubricant outlets 15 and 15', each connected to the cylindrical bore 7 via a lubricant channel 17 or 17', respectively. The cylindrical bore 7 also has a lubricant inlet 19 through which lubricant in the form of oil or grease can be supplied.The lubricant distributor 1 is connected to a lubricant reservoir via lines and also has a control piston, which is not shown here. The metering piston 9 has two constrictions 21 and 21' through which lubricant can be drawn into the correspondingly formed cavities 23 and 23' in front of the lubricant inlet 19 when the metering piston 9 is in the appropriate horizontal position. In the case of the... Fig. In the position shown in Figure 1, lubricant is drawn into the cavity 23' formed by the constriction 21'. Simultaneously, lubricant in the cavity 23 is conveyed to the lubricant outlet 15 via the lubricant channel 17 and discharged to a consumer via a connecting line (not shown). Upon subsequent movement of the metering piston 9 to the right, the cavity 23 comes into contact with the lubricant inlet 19, thereby refilling it with lubricant. At the same time, the cavity 23' is in contact with the lubricant channel 17', so that the lubricant contained within it is discharged to a consumer. This operating principle is well known.

[0024] The display unit 3, which comprises a housing 31 with a corresponding internal thread 33, is screwed into the bore 11'. The housing 31 is divided into two sections by a partition 35. The section shown on the left has a cavity 36 in which the metering piston 9 is received when moved to the right. The display unit 3 also has a pin 37, which is screwed into the metering piston 9 at one end via a thread 39. At the opposite end 41, the pin 37 protrudes from the housing 31, so that its axial position is visible from the outside. The partition 35 accordingly has an opening through which the pin 37 protrudes. To prevent lubricant from escaping, the section of the housing 31 shown on the right has a sealing unit 43, which is held in the housing 31 and seals around the pin 37.

[0025] Due to its relatively simple design, the current position of the metering piston 9 can be easily determined from the outside. However, in many applications, the metering piston 9 remains in the position it is in for a significantly longer period of time. Fig. The basic position shown in Figure 1 is shown. Only when a lubrication process is triggered does it move to the right and then back to the left to dispense lubricant to both lubricant outlets 15 and 15'. This process lasts only a few seconds, after which there is often no lubrication and therefore no movement of the metering piston 9 for several minutes to several hours. To ensure the proper functioning of the lubricant distributor 1, the pin 37 must therefore be continuously monitored to detect any movement.

[0026] In the Fig. Figure 2 shows a detector 101 according to an embodiment of the invention. It can be used, for example, as a replacement for the display unit 3 in the lubricant distributor 1. Its functionality is superior to that of the display unit 3. The detector 101 has a housing part 103 which is provided with an external thread 104.

[0027] The detector 101 can be inserted into one of the bores 11 or 11' using this device. The housing part 103 also has a partition 105, which, analogous to that of the display unit 3, has an opening and divides the housing part 103 into two sections. The left section has a cavity 107 in which the metering piston 9 is received when moved to the right. A cavity 109 is formed in the right section. A transmission unit 111 is arranged in the cavity 109, comprising a cylindrical permanent magnet 113 connected to a pin unit 115. The transmission unit 111 is axially movable in the cavity 109, but is acted upon by a spring 117 and pressed against the partition 105. The pin unit 115 has a pin 119 which extends through the opening of the partition 105 into the cavity 107.

[0028] The detector 101 has a second housing part 131, which is connected to the housing part 103 via a screw connection 133. Numerous other connection types are conceivable here, such as an adhesive connection or a tight press fit. The housing part 131 has a cavity 134, which enlarges the cavity 109 and partially accommodates the spring 117. Its inner diameter corresponds to the outer diameter of the spring 117 or is slightly larger. The housing part 131 has a radially outer running surface 135 on which an axially displaceable magnetic ring 137 is mounted. The magnetic ring 137 consists of a permanent magnet whose axial orientation with respect to the permanent magnet 113 is chosen such that a repulsive magnetic force exists between the two. In the Fig. In the position of permanent magnet 113 and magnetic ring 137 shown in Figure 2, which corresponds to a basic position of the detector 101, the axial distance between permanent magnet 113 and magnetic ring 137 is chosen to be such that the repulsive magnetic force is so small that the magnetic ring 137 is not axially displaced. In this position, the magnetic force cannot overcome the frictional force acting between the running surface 135 and the magnetic ring 137; it is therefore smaller than this force. The magnetic field strengths of permanent magnet 113 and magnetic ring 137 are correspondingly matched.

[0029] The housing part 131 also has a seat 139 which, together with the extension of the running surface 135, forms an annular step 141. A retaining unit 143 is mounted on the seat 139, for example by means of a screw connection, an adhesive layer, or an interference fit. The retaining unit 143 has a section 145 extending towards the running surface 135, which terminates at the end of the running surface 135. The retaining unit 143 is made of a soft magnetic material (e.g., 9SMn28k or 16MnCr5) and can therefore be magnetized by the proximity of a permanent magnet. This results in an attractive magnetic force between the retaining unit and the permanent magnet of the magnetic ring 137. When the permanent magnet is removed, the magnetization is lost again within a short time, so that the attractive magnetic force disappears.

[0030] The detector 101 has a cap 151 that forms a cavity 153 and is axially displaceable on the holding unit 143, for example by a loose press fit. A spring 155 is held in the cavity 153, pressing against an inner end face 157 of the cap 151 and, opposite it, against an end face 158 of the holding unit 143. In the Fig. In the axial position of the cap 151 shown in Figure 2, the spring 155 is relaxed, so that no force is exerted. At the end of the cap 151 axially opposite the inner face 157, it has a section 159 that covers the running surface 135, the magnetic ring 137, and partially a corresponding section 161 of the housing part 131. At least in the area of ​​section 159, the cap 151 is transparent, so that the position of the magnetic ring 137 is visible from the outside. The wall thickness of the cap 151 is thinner in the area of ​​section 159 than on the rest of the cap 51, so that a shoulder 163 is formed. The shoulder 163 extends radially inwards to such an extent that it radially overlaps the magnetic ring 137.

[0031] In the following Fig. 3 and Fig. Section 4 describes the detector 101 in various installation situations, while the Fig. 5 and Fig. 6 explains the functionality in detail.

[0032] In the Fig. Figure 3 shows a partial view of a lubricant distributor 300. It comprises, in particular, a housing 303 with at least one cylindrical bore 305. A metering piston 307 is movably arranged in the cylindrical bore 305. The other design features of the lubricant distributor 301, which is designed here as an inlet distributor, are well known from the prior art and are therefore not discussed further here. Lubricant is dispensed to lubricant outlets (not shown) by movement of the metering piston 307. Fig. At the right end of the cylindrical bore 305 shown in Figure 3, an enlarged bore 309 is formed, which has an internal thread 311. A detector 101 is screwed into the internal thread 311, the design of which is similar to that shown in the Fig. This corresponds to the detector 101 shown in Figure 2. The detector 101 is depicted here in its basic state with respect to the position of the transmission unit 111 and the ring magnet 137. Some construction details are not shown here. The metering piston 307 is in the middle of a lubrication cycle and is moving towards the pin 119 of the detector 101. It penetrates the cavity 107 and begins to press against the pin 119. As the metering piston 307 moves further to the right, the pin 119, and thus the entire transmission unit 111, is pushed to the right, compressing the spring 117. The force required for this is generated by the movement of the metering piston 307. Between the permanent magnet 113 and the ring magnet 137, an axial displacement of the ring magnet 137 occurs as the transmission unit 111 advances due to the prevailing repulsive magnetic force.The effects on the function of detector 101 are described in detail using the following. Fig. 5 and Fig. 6 explained in more detail.

[0033] In the Fig. Figure 4 shows a partial and schematic representation of a lubricant distributor 401. In this case, it is a so-called progressive distributor. The description of the Fig. Section 4 describes only the essential design features of the invention, while design features that are known per se are not explained in detail. These can be found in the numerous existing prior art documents relating to progressive distributors. The lubricant distributor 401 comprises, in particular, a housing 403 in which a cylindrical bore 405 is formed. A metering piston 407 is movably arranged in the bore 405. This is comparable to the design described in the Fig. In the lubricant distributor 301 shown in section 3, a detector 101 is also located at the end of the bore, according to the embodiment shown in section 3. Fig. 2. Here too, the lubricant distributor 401 and thus also the metering piston 407 are in a lubrication cycle at the time when the metering piston 407 comes into contact with the pin 119 during its movement to the right.

[0034] In the Fig. Figure 5 shows a section of the operating state in which the metering piston 307 or 407 has reached its maximum deflection at the right end of its movement cycle. In this case, it almost completely fills the cavity 107 of the detector 101 and abuts the partition 105. As a result, the transmission unit 111 is also displaced to the right to its maximum extent and the spring 117 is compressed to its maximum extent.

[0035] Accordingly, due to the repulsive magnetic field force between permanent magnet 113 and ring magnet 137, the ring magnet 137 was displaced to the end of the running surface 135 and thus rests against the holding unit 143 and the shoulder 163 of the cap 151. The proximity of the ring magnet 137 magnetizes the holding unit 143, which in turn exerts an attractive magnetic force on the ring magnet 137. Subsequently, as the lubrication cycle progresses, the metering piston 307 or 407 moves backward, which in the Fig. 6 is shown in detail.

[0036] In the Fig. 6. The metering piston 307 or 407 has moved back to the left as part of its lubrication cycle and has thus retracted completely from the cavity 107. Due to the previously tensioned spring 117, a force acting in the same direction is exerted on the transmission unit 111, which has thus been moved back to its home position and is resting against the partition 105. The ring magnet 137, on the other hand, remains at the right-hand edge of the running surface 135, as no force acts on it that would cause it to move to the left. In addition, the ring magnet 137 is held in its position shown by the attractive force of the holding unit 143. The change in position of the ring magnet 137 can be easily observed from the outside through the transparent cap 151 in section 159.Therefore, for example, a maintenance technician can determine during a routine visual inspection of the lubricant distributor whether at least one lubrication cycle has taken place since the last visual inspection, i.e., whether the lubricant distributor is functioning correctly. Due to the holding force of the retaining unit 143, the ring magnet 137 remains securely in the position shown, even in the event of shocks and vibrations, thus preventing a false negative result during the visual inspection. This is in contrast to the [reference to the diagram]. Fig. The 1 depicted, known display unit offers a decisive advantage.

[0037] After completing the visual inspection, the maintenance technician can overcome the holding force of the retaining unit 143 by simply pushing the cap 151 to the left and push the ring magnet 137 back to the left end of the running surface 135, so that the next lubrication cycle can again be indicated by the detector 101. The cap 151 is released by the mechanism in the Fig. 6. Spring 155 (not shown) was moved back to its basic position.

[0038] A detector 101 according to the invention can be easily adapted in its design details to various types and designs of lubricant distributors and can also be mounted on existing systems. Since the pin 119 of the detector 101 does not need to be permanently connected to the piston to ensure reliable detection of the proper functioning of the lubricant distributor, the metering piston also does not need to have any special features, such as a receiving thread as in the Fig. 1. A detector according to the invention can therefore be easily retrofitted to existing lubricant distributors. Its design is comparatively simple and it can be safely operated by maintenance technicians. The cap 151 also provides reliable protection against contamination. The entire detector 101 requires no dynamic seal since no moving part penetrates the housing. Therefore, lubricant leakage is impossible.

[0039] In the Fig. Figures 7 to 10 show various further embodiments of the invention, in which the design of the holding element differs in particular. The basic working principle of the invention is realized in all embodiments.

[0040] In the Fig. Figure 7 shows a detector 601, which is analogous to detector 101 of the Fig. 5 and Fig. 6 is constructed. However, no separate holding unit 143 is provided here. Instead, the spring 155 is made of a magnetizable material and is dimensioned and arranged such that the magnetic ring 137 can be slid over it. This results in a holding force, analogous to the holding unit 143 of the detector 101, so that the magnetic ring 137 is not moved back when the permanent magnet 113 moves back. This design is particularly simple due to the dual function of the spring 155.

[0041] In the Fig. Figure 8 shows a detector 701, which in turn is analogous to detector 101 of the Fig. 5 and Fig. 6 is constructed. Here, the retaining element is designed as a thin ring 170 over which the magnetic ring 137 can be slid. The ring 170 consists, for example, of a thin metal foil made of a magnetizable material and fulfills the same function as the retaining unit 143. In addition, the ring 170 has at least a partial surface that is finished in a signal color, e.g., green, which differs from the color of the rest of the detector. This allows the maintenance technician to determine at a glance that the ring 170 is present, provided it is not obscured by the magnetic ring 137. Furthermore, after actuating the cap 151, it is easy to see that the magnetic ring 137 has been returned to its initial position, as the ring 170 is then visible again. This also applies to the other embodiments, in which a corresponding area of ​​the housing is finished in the signal color.

[0042] In the Fig. Figure 9 shows a detector 801, which in turn is analogous to detector 101 of the Fig. 5 and Fig. 6 is constructed. Here, the holding unit 171 is designed in a disc-like form and is arranged between the spring 155 and the housing part 131.

[0043] In the Fig. Figure 10 shows a detector 901, which in turn is analogous to detector 101 of the Fig. 5 and Fig. 6 is constructed. Here, the holding unit 172 is arranged between the spring 117 and the housing part 131. Reference symbol list 1 lubricant distributor 3 Display unit 5 cases 7 cylinder bore 9 metering pistons 11, 11' bore 13. Locking piece 15, 15' Lubricant outlet 17, 17' Lubrication channel 19 Lubricant inlet 21, 21' constriction 23, 23' cavity 31 cases 33 internal threads 35 Partition wall 36 cavity 37 pen

Claims

[1] Detection device (101; 601; 701; 801; 901) for piston movement of a lubricant distributor (301; 401), comprising the following features: - a movable actuating element (111) with a magnetic device (113), wherein the magnetic device (113) of the actuating element (111) is designed as a cylindrical permanent magnet, - a movable magnetic element (137), wherein the magnetic element (137) is designed as a ring-shaped permanent magnet (137) and is arranged axially spaced from the actuating element (111), - wherein the actuating element (111) is designed such that it can be moved from an initial position to an end position by a movement of the piston (307; 407) in the direction of the actuating element (111), - wherein the magnetic device (111) and the magnetic element (137) are designed and arranged such that a repulsive magnetic force exists between them, by which, when the actuating element (111) is moved from the initial position towards the end position, the magnetic element (137) is movable from a basic position to a holding position, such that when the magnetic device (113) is in the initial position and when the magnetic element (137) is in the basic position, such a magnetic force acts between them that the magnetic element (137) is not displaceable, and such that when the actuating element (111) is moved from the initial position towards the end position, such a large repulsive magnetic force can be exerted by the magnetic device (113) on the magnetic element (137) that the magnetic element (137) is displaceable. [2] Detection device (101; 601; 701; 801; 901) according to claim 1, further comprising a holding element (143, 171, 172) which is designed such that a holding force can be exerted on the magnetic element in the holding position. [3] Detection device (101; 601; 701; 801; 901) according to one of claims 1 or 2, wherein the actuating element (111) has a pin element (119) which, in the installed state, is arranged on the actuating element (111) pointing towards the piston (307; 407) and whose length is selected such that the piston (307; 407) can exert a force on the pin element (119) only in an end region of its movement, thus displacing the pin element (119). [4] Detection device (101; 601; 701; 801; 901) according to one of claims 2 to 3, wherein the holding element (143, 171, 172) consists at least partially of a magnetizable material. [5] Detection device (101; 601; 701; 801; 901) according to one of the preceding claims, further comprising a reset element (151) by means of which the magnetic element (137) can be moved from the holding position to the home position by overcoming the holding force. [6] Detection device (101; 601; 701; 801; 901) according to claim 5, wherein the reset element is designed as a movable cap element (151) that covers the magnetic element (137) and is transparent in the area of ​​the magnetic element. [7] Detection device (101; 601; 701; 801; 901) according to one of the preceding claims, further comprising a force element (155) by means of which the actuating element (111) can be brought from the end position to the initial position. [8] Detection device (101; 601; 701; 801; 901) according to claim 7, wherein the force element (155) is designed as a spring element. [9] Lubricant distributor (301; 401) with a housing block (303; 403) and at least one piston (307; 407) guided in a piston bore (305; 405), comprising at least one detection device (101; 601; 701; 801; 901) according to one of claims 1 to 8.

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