US20140224832A1

US20140224832A1 - Device for metering lubricants in metal cutting

Info

Publication number: US20140224832A1
Application number: US14/124,160
Authority: US
Inventors: Werner Studer
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-06-08
Filing date: 2012-06-01
Publication date: 2014-08-14
Also published as: WO2012168157A1; EP2718569A1

Abstract

The pump block of a metering pump for metering liquids including a first feed duct system for the liquid to be delivered; a metering chamber connected to said feed duct system; a pump duct; a metering piston arranged in the metering chamber such that it can slide along an axis, said metering piston being set up to pump a certain quantity of a liquid present in the metering chamber through a stop valve into the pump duct when moved in a direction along said axis; and an actuator device for moving the metering piston along said axis.

Description

TECHNICAL FIELD

The invention relates to metering pumps for liquids, particularly lubricants, as well as lubricant metering devices for minimum-quantity cooling lubrication in metalworking.

BACKGROUND

In metal cutting, it is usually necessary to cool and/or lubricate the tool during machining in order to achieve the required quality and extend the service life of the tool. Combined cooling and lubrication can be achieved, for example, using conventional emulsion cooling lubrication. The cooling emulsions used for this contain about 3-6 vol. % of oil-like lubricant in water. Relatively large quantities of cooling emulsion are needed which, due to their composition, then require expensive disposal and can be harmful to health.
The amount of lubricant needed can be reduced with minimum-quantity cooling lubrication. With it, small quantities of viscous lubricant/cutting oil are delivered in a continuous airflow and applied in a targeted manner onto the tool and/or workpiece over a short distance as an atomized spray. The airflow simultaneously provides for cooling.
The lubricant is applied directly in the cutting area. In doing so, the quantities of lubricant required are substantially smaller than with conventional cooling emulsion. Accordingly, the operating costs are lower. Other advantages of minimum-quantity cooling lubrication are higher cutting speeds, dry workpieces, lower environmental burden and less cleaning effort. Since the machined-off material also remains dry, it is easier to recycle. Furthermore, no emulsion fogs or vapors are generated that are harmful to health, which increases workplace safety.
In order to transport the viscous lubricant to the target site, small quantities of the lubricant are introduced into a continuous pressurized airflow and carried along by it. This occurs, for example, with a coaxial metering nozzle in which an inner nozzle for the lubricant is arranged within the outer annular nozzle for the pressurized air.
In a known system, the lubricant is delivered pneumatically using pneumatically actuated metering pumps which deliver small quantities of lubricant via a delivery line to the nozzle and from there into the airflow. A separate metering pump is used there for each metering nozzle.
Such pneumatic metering pumps are known, for example, from U.S. Pat. No. 3,888,420 and U.S. Pat. No. 4,125,176. In these metering pumps, a metering piston is pushed by a pulse of pressurized air in a metering chamber filled with the viscous lubricant to be delivered, whereby a defined quantity of liquid is pressed through a non-return valve into a delivery line. Accordingly, at the other end of the delivery line, the same quantity of liquid is forced out through a coaxial nozzle into a continuous pressurized airflow, where it is carried along and atomized, thus reaching the tool.
FIG. 1 shows an example of such a metering pump 1 from the prior art. In a cuboid pump mechanism 10, a cylindrical metering chamber 12 is arranged in the direction of the longitudinal axis 101. This [metering chamber] is sealed on one side with a stop valve 131 and connected on the other side to a feed duct system 11. The feed duct system 11 feeds the liquid 21 to be metered, that is, the lubricant, into the metering chamber 12. A metering piston 13 that can be actuated by a pneumatic actuator device 16 is arranged so as to slide along the longitudinal axis 101. The pneumatic actuator device comprises an actuator piston 163 operatively connected to the metering piston 14 that is arranged in an actuator cylinder 162 such that it can slide in the longitudinal direction 101.
The actuator cylinder 162 is connected to a feed duct system 17 for the pneumatic medium, usually pressurized air. Without pressurization of the actuator, a return spring 161 presses the actuator piston in the actuator cylinder into the home position (toward the left in the depicted example). The front end 141 of the metering piston is located in a position in which the lubricant 21 can continue to flow from the feed duct 11 into the metering chamber 12.
If pressure is now applied to the actuator cylinder 162 via the feed duct 17, then the actuator piston 163 moves to the right in the cylinder, and with it the metering piston 14, until the provided end position is reached. In doing so, the metering piston first seals the metering chamber off from the feed duct 11 and subsequently forces the viscous lubricant located within it through the stop valve 131 into the pump duct 13 and the lubricant delivery line 45 connected to it.
Since the metering pump and therefore the cross section of the actuator piston is relatively small, the pressure must be commensurately large in order to produce the required force. Several bar can be necessary. The pressurization occurs as a short pulse that is produced by a corresponding pressure pulse generator (not shown). After the end of the pressure pulse, the return element 161 moves the metering piston 14 again to the left. The stop valve 131 closes, and liquid 21 continues to flow into the chamber 12.
At the longitudinal-side end of the actuator 16, a knob 165 is provided with which the actual can also be operated manually by pressing the knob.
In the depicted exemplary embodiment, the position of the metering piston can be adjusted and adapted in relation to the actuator piston 163 in the longitudinal direction to a certain degree. For this purpose, the metering piston can be extended beyond the actuator piston and provided with an external thread 164. The external thread is screwed into a corresponding continuous thread of the actuator piston, and the two elements are thus joined together in a positive manner. When the knob 165 is turned, the metering piston rotates in the thread of the actuator piston and moves accordingly in the longitudinal direction 101. The home position and the end position of the actuator piston in the actuator cylinder, and hence also the stroke of the metering piston, is established by appropriate stops. However, by moving the metering piston, the home position and the end position of the metering piston can be adjusted and, with it, the actual effective stroke within the metering chamber that determines the delivered volume of lubricant per stroke.
For lubricant metering devices with several lubrication nozzles, the metering pumps required for them are preferably supplied via a common lubricant feed. An especially compact device is known from U.S. Pat. No. 5,725,071 in which the metering pumps are stacked. Metering pumps for such devices, such as the pump from FIG. 1, for example, must be designed appropriate for this purpose. The feed duct system 11 for the liquid 21 in such a metering pump has an opening 111, 111′ on two opposing parallel side walls 102, 102′. A recess 103, 103′ around the opening is used to accommodate a sealing element in the form of an O-ring.
Several such identical, individual metering pumps 1, 1 a, 1 b embodied as cuboid pump blocks 10 are combined into a stack as shown schematically in FIG. 2 in a cross section through the feed duct 11. The openings 111, 111′ of the feed duct system are arranged here such that, when the pump blocks are stacked, the openings of adjacent metering pumps lie one on top of the other, with an O-ring 104 or another suitable sealing means ensuring a sealing connection. This results in a continuous feed line for the pump stack 42 comprising the individual feed duct systems 11 connected in a sealing manner. At its lower end, the feed line is sealed by a closure block 414 and at its upper end by a connection block 415 for the feed line 46, which is connected to a reservoir 43 for the liquid. The liquid flows by force of gravity from the reservoir 43 to the pumps. Alternatively, delivery into the feed can be achieved through the constant application of pressure.
Analogously, in the metering pump 1 from FIG. 1, the feed duct system 17 for the pneumatic medium is also embodied such that, when several metering pumps are stacked, a common feed line results. In this way, several metering pumps can be operated simultaneously by a single pulse of pressurized air.
In the example shown, the pump blocks 10 of the standardized metering pumps 1, 1 a, 1 b are arranged between two clamping plates 413 that press the pump blocks 10 along the stack axis in a positive and nonpositive manner by means of clamping bolts 410 and nuts 411. This enables cost-effective manufacturing of the entire lubricant metering device 4, with the number of pumps being changable as needed. In this way, the individual lubricant metering devices can be adapted efficiently to individual customer preferences. Only the length of the clamping bolts 410 need be selected accordingly.
The pump stack of such a conventional metering device enables trouble-free assembly. However, if a malfunction occurs in a single metering pump during operation and it needs to be changed out for repair, then the entire pump stack 42 has to be emptied, disassembled and broken down. This leads to expensive down time of the affected metalworking machines. The danger of missing scheduled maintenance cycles is also just as great, which can then lead to even greater malfunctions.

Object of the Invention

It is one object of the invention to provide metering pumps for liquids, particularly lubricant, and lubricant metering devices for metal cutting which do not have the drawbacks of the prior art.
Particularly, the intention is to enable the individual and efficient construction of such lubricant metering devices. The individual metering pumps of such a lubricant metering device and their faster-wearing parts are to be exchangeable in a quick and simple manner.
It is another object of the invention to provide lubricant metering devices and metering pumps for such devices for which there are shorter down times as a result of maintenance work.
In addition, such lubricant metering devices and metering pumps are to be manufacturable in an efficient and cost-effective manner.
These and other objects are achieved by an inventive lubricant-metering pump and an inventive lubricant metering device according to the independent claims. Additional advantageous embodiments are described in the dependent claims.

Description of the Invention

The inventive metering pump for metering liquids has at least one pump block comprising a first feed duct system for the liquid to be delivered, a pump duct, and a pump device for pumping the liquid from the feed duct system into the pump duct. The pump block has a housing cover in the form of a cylinder or a truncated cone, and the feed duct system leads to at least one opening arranged in the housing cover.
Advantageously, the pump device of the metering pump has a metering chamber connected to the first feed duct system, a metering piston arranged so as to be slidable in the metering chamber along an axis, and an actuator device for moving the metering piston along the abovementioned axis, the metering piston being set up to pump a certain quantity of the liquid present in the metering chamber through a stop valve into the pump duct.
Also advantageously, the actuator device of the metering pump is set up to operate the metering piston electromagnetically or pneumatically.
An especially advantageous variant of a metering pump according to the invention has a pneumatic actuator device that can be driven through a pneumatic medium, particularly pressurized air, and a second feed duct system for the pneumatic medium for operating the pneumatic actuator device. This second feed duct system leads to at least one opening arranged in the housing cover.
The actuator device can have a return element for the metering piston, for example a return spring.
An especially advantageous embodiment of a metering pump according to the invention has a mounting block with at least one receptacle that is adapted to the shape of the housing cover of the pump block. The pump block can be arranged flush in the receptacle. Such a metering pump can comprise means for fixing the pump blocks in the receptacle of the mounting block. Advantageously, such a metering pump comprises recess, particularly a circumferential groove on the housing cover of the pump blocks, as well as a screw arranged in a continuous threaded hole in the mounting block, the groove, threaded hole and screw being embodied and arranged such that, when a pump block is mounted, the screw can engage reversibly with the groove, thus enabling the reversible positive attachment of the pump block in the mounting block in the direction of the longitudinal axis. Especially advantageously, the screw is made of a material that has a lesser hardness than the cover of the pump block. For example, if the cover is made of steel or brass, then the screw can be made of a polymer, for example.
The mounting block of an advantageous embodiment of such a metering pump according to the invention has a third feed duct system for the liquid. A circumferential groove is provided on the wall of the receptacle that is connected to the third feed duct system. The groove is arranged such that the at least one opening of the first feed duct system of a pump block arranged in the mounting block overlaps with the first circumferential groove, so that the first and third feed duct systems form a continuous feed duct system for liquid.
The mounting block of another advantageous embodiment of such a metering pump according to the invention has a third feed duct system for the liquid that leads to at least one opening arranged in the wall of the receptacle. A first circumferential groove is provided on the housing cover of the pump block arranged in the mounting block that is connected to the first feed duct system. The groove is arranged such that the at least one opening of the third feed duct system overlaps with the first circumferential groove, so that the first and third feed duct systems form a continuous feed duct system for liquid.
Especially advantageously, such metering pumps have sealing elements that are arranged in the receptacle of the mounting block and/or around the housing cover of the pump blocks along the periphery. They are suited to connecting the at least one opening of the first feed duct system or of the third feed duct system and the first circumferential groove in a sealing manner.
The mounting block of the metering pump can have a fourth feed duct system for pneumatic medium, and a second circumferential groove on the wall of the receptacle that is connected to the fourth feed duct system. The groove is arranged such that the at least one opening of the second feed duct system of a pump block arranged in the mounting block overlaps with the second circumferential groove, so that the second and fourth feed duct systems form a continuous feed duct system for pneumatic medium.
Likewise, in another embodiment of the mounting block, the metering pump can have a fourth feed duct system for pneumatic medium that leads to at least one opening arranged in the wall of the receptacle. A second circumferential groove is provided on the housing cover of a pump block arranged in the mounting block that is connected to the second feed duct system and is arranged such that the at least one opening of the fourth feed duct system overlaps with the second circumferential groove. The second and fourth feed duct systems thus form a continuous feed duct system for pneumatic medium.
In this case as well, it is especially advantageous if such metering pumps have sealing elements that are arranged in the receptacle of the mounting block and/or around the housing cover of the pump block along the periphery and that are suited to connecting the at least one opening of the second feed duct system or of the fourth feed duct system and the second circumferential groove in a sealing manner.
Advantageously, the mounting block of a metering pump according to the invention has two parallel, flat walls. Such a metering pump offers the advantage that it can be assembled in a stack and thus saves space.
In an especially advantageous variant, the mounting block has two parallel, flat walls, and the third feed duct system leads to an opening on both walls. The two openings are arranged such that one opening coincides with a corresponding opening of another identical metering pump when the two metering pumps are placed with their walls one on top of the other.
Analogously, the mounting block can have two parallel, flat walls, and the fourth feed duct system leads to an opening on both walls, the two openings being arranged such that one opening coincides with a corresponding opening of another identical metering pump when the two metering pumps are placed with their walls one on top of the other.
A lubricant metering device according to the invention has at least one inventive metering pump.
In an advantageous variant, a lubricant metering device according to the invention has two or more inventive metering pumps, these having a mounting block with a receptacle that is adapted to the shape of the housing cover of a pump block of the metering pump and in which the pump block can be arranged and fixed so as to be flush.
In an especially advantageous embodiment, two or more metering pumps are arranged in a stack in such a lubricant metering device according to the invention, with two parallel, flat walls of the mounting blocks of two adjacent metering pumps lying flush one on top of the other. A lubricant metering device can further comprise a reservoir for the liquid, a common feed duct system of the metering pumps for the liquid, and a stop valve for the reversible separation of the feed duct system from the reservoir.
Advantageously, in such an embodiment of a lubricant metering device according to the invention, a means is provided for the detachable connection of the mounting blocks of two adjacent metering pumps. Especially advantageously, this connection means comprises clips or clamps that are connected in a non-positive manner to the mounting blocks to be connected.
Preferably, these clips or clamps are embodied such that, when the non-positive connection of the clips or clamps to the mounting blocks to be connected is established, the mounting blocks are braced against each other.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate understanding of the present invention, reference is made in the following to the drawings, which merely show exemplary embodiments of the object of the invention.

FIG. 1 shows a schematic view of a longitudinal section through a pneumatic lubricant-metering pump as is known from the prior art.

FIG. 2 shows a schematic cross section through lubricant metering devices with several stacked metering pumps as is known from the prior art.

FIG. 3 shows a schematic view of one embodiment of a metering pump according to the invention (a) as a longitudinal section only through the pump block, (b) as a longitudinal section only through the mounting block, (c) as a cross section only through the mounting block along the plane A-A, and (d) as a longitudinal section through the mounting block and pump block in the assembled state.

FIG. 4 shows a schematic cross section through two metering pumps from FIG. 3 in a stacked arrangement.

FIG. 5 shows a schematic view of detail of an embodiment of a metering pump according to the invention with longitudinal-side attachment of the pump block in the mounting block.

FIG. 6 shows a schematic view of detail of an embodiment of a metering pump according to the invention with lateral attachment of the pump block in the mounting block.

FIG. 7 shows a schematic view of a variant of a metering pump according to the invention in which the circumferential grooves of the feed duct system are arranged on the cylindrical cover 15 of the pump block (a) as a longitudinal section through the mounting block and pump block in the assembled state, and (b) as a longitudinal section only through the mounting block.

FIG. 8 shows a schematic view of a longitudinal section (a) through an especially advantageous variant of a metering pump according to the invention, and (b) only through the mounting block.

FIG. 9 shows a side view of the pump block of yet another especially advantageous embodiment of a metering pump according to the invention.

FIG. 10 shows a mounting block fitting with the pump block from FIG. 9, (a) in a top view of the mounting block, (b) in a side view of the mounting block, (c) in a longitudinal section through the two side walls of the mounting block along the plane A-A, (d) in a cross section through the plane B-B, (e) in a cross section through the plane C-C, and (f) in a cross section through the plane D-D.

FIG. 11 shows an advantageous clip for the positive and nonpositive connection of two metering pumps according to the invention (a) in a top view, and (b) in a section through the plane F-F.

FIG. 12 shows another mounting block fitting with the pump block from FIG. 9, with a connection for a reservoir and a shut-off valve (a) in a top view of the mounting block, (b) in a side view of the mounting block, (c) in a longitudinal section through the two side walls of the mounting block along the plane A-A, (d) in a cross section through the plane C-C, and (e) showing a shut-off valve for the lubricant feed.

FIG. 13 shows a cross section through a metering device according to the invention, with a reservoir and one respective metering pump according to the invention from FIG. 12 and FIG. 15, in a stacked arrangement.

FIG. 14 shows another possible mounting block fitting with the pump block from FIG. 9, with two receptacles for pump blocks (a) in a top view of the mounting block, (b) in a side view of the mounting block, (c) in a longitudinal section through the two side walls of the mounting blocks along the plane A-A, (d) in a cross section through the plane B-B, (e) in a cross section through the plane C-C, and (f) in a cross section through the plane D-D.

FIG. 15 shows a schematic cross section of yet another advantageous embodiment of a mounting block fitting with the pump block from FIG. 9, with receptacles for two pump blocks and with a connector for a reservoir and a shut-off valve.

IMPLEMENTATION OF THE INVENTION

The examples given below are being provided in order to better illustrate the present invention but are not intended to limit the invention to the features disclosed therein.
FIG. 3 shows a schematic view of an advantageous embodiment of a metering pump according to the invention. The metering pump comprises a substantially cylindrical pump block 10 that is arranged in an appropriately shaped mounting block 30.
The pump block 10 contains the actual pneumatic pump device that corresponds to the pump device from FIG. 1 in terms of its functional principle. A cylindrical metering chamber 12 is arranged in the pump body 10 in the direction of the longitudinal axis 101 that is closed on one side with a stop valve 131 and is connected on the other side to a feed duct system 11. A metering piston 14 is arranged so as to be slidable along the longitudinal axis and is operated by a pneumatic actuator device 16. The pneumatic actuator device 16 comprises an actuator piston 163 operationally connected to the metering piston 14 that is arranged so as to be slidable in the longitudinal direction in an actuator cylinder 162. The actuator cylinder 162 is connected to a feed duct system 17 for the pneumatic medium. Without the pressurization of the actuator, a return spring 161 presses the actuator piston in the actuator cylinder into the home position (as shown).
If pressure is applied to the actuator cylinder 162, then the actuator piston 163 and the metering piston 14 move to the right, and the viscous lubricant located in the metering chamber 12 is pressed through the stop valve 131 into the pump duct 13 and the lubricant delivery line 45. In the example shown, the lubricant delivery line 45 is connected in a sealing manner to the pump block 10 via a corresponding threaded connection piece 451.
After the end of the pressure pulse, the return element 161 moves the metering piston 14 to the left again back into the home position. The stop valve 131 closes, and liquid continues to flow from the feed duct system 11 into the chamber 12.
A knob 165 is provided on the longitudinal-side end of the actuator 16 with which the actuator can be manually operated. The position of the metering piston in relation to the actuator piston 163 can be adjusted in the longitudinal direction in order to adjust the effective stroke within the metering chamber. The metering piston extended beyond the actuator piston is provided with an external thread that is screwed into a corresponding internal thread of the actuator piston. By turning the knob 165, the metering piston moves relative to the actuator piston.
The mounting block 30 has a cuboid outer shape. The metering pump, analogously to the one-piece metering pumps according to FIG. 1, can therefore be assembled in a stacking manner. A cylindrical hollow space is provided within the mounting block in alignment with the longitudinal axis 101 that serves as a receptacle 31 for the cylindrical pump block 10. A first longitudinal-side opening 312 serves as an insertion opening for the pump block 10 into the mounting block 30. A second longitudinal-side opening 313 enables access to the convection for the delivery line delivery line 45.
Two circumferential flutes 33, 36 are arranged in the mounting block 30 on the inner wall 311 of the receptacle 31. These flutes or grooves or recesses are connected to a third 32 or fourth 35 feed duct system arranged in the mounting block. In the example shown, the cuboid mounting block 30, on two opposing walls 302, 303, has two openings of the third feed duct system 32 for the liquid to be pumped. Likewise, two corresponding openings of the fourth feed duct system 35 are provided for the pneumatic medium. The openings of the third and fourth feed duct systems are arranged such that, when equivalent metering pumps according to the invention are placed in a stacked arrangement, the mutually corresponding openings of adjacent metering pumps lie one over the other. O-rings 104 or other suitable sealing means are arranged in corresponding circular recesses 103 and ensure a sealing connection between the individual metering pumps.
In the depicted embodiment, the position of the recesses 33, 36 in the lateral surface 311 of the receptacle 31 is selected such that, in the assembled metering pump 1, the openings 111, 111′, 171, 171′ of the first feed duct system 11 and of the second feed duct system 17 lie on the lateral surface 15 of the pump block 10 on the corresponding flutes 33, 36 on the inner wall 311. When seen in the longitudinal direct ion 101, sealing elements 331, 331′ or 361, 361′ are arranged on both sides of the openings 111, 111′ and 171, 171′ circumferentially around the cylindrical cover 15 of the pump block 10. In the example shown, these are O-rings that are arranged in corresponding recesses on the lateral surface 15. The abovementioned sealing elements ensure a sealing connection between the first 11 and third 32 feed duct system or the second 17 and fourth 36 feed duct system. This results in a continuous feed duct system 11, 31, 32 within the metering pump 1 for the liquid to be delivered, as well as a continuous feed duct system 17, 35, 36 for the pneumatic fluid.
One great advantage of such a configuration of the metering pump 1 according to the invention is the fact that the pump block can be mounted in any position in the mounting block in relation to the rotational position around the longitudinal axis 101. Independently of the rotational alignment of the pump block 10, a continuous connection is ensured via the grooves 33, 36. This facilitates the installation of the pump block 1 of a metering pump 1 according to the invention that need substantially only be pushed into the receptacle of the mounting block until reaching the longitudinal-side stop 314.
The housing cover 15 of the pump block 10 and the receptacle 31 of the mounting block 30 advantageously have as little backlash as possible. Consequently, the sealing rings and their mounting grooves can be dimensioned such that the sealing rings are plastically deformed as little as possible in an assembled metering pump and have a commensurately longer service life. In practice, the manufacturing tolerance of the cover 15 and receptacle 31 is advantageously set at 5 micrometers or less. Accordingly, such precise dimensioning also necessitates careful handling of the pump block cover 15 during transport and assembly.
FIG. 4 shows a section from a stack 42 of inventive metering pumps 1, 1 a according to FIG. 3, in cross section through the feed duct system 11 for the lubricant. As can be seen, the pump block 10 is arranged in one metering pump 1 such that the first feed duct system 11 is aligned with the third feed duct system 32. In the other metering pump 1 a, in contrast, the pump block 10 a is rotated with respect to the mounting body mounting body 30 a. Nonetheless, the first feed duct system 11 a is connected to the third feed duct system 32 a via the circumferential groove 33 a. The orientation of the pump blocks 10 is not relevant to the function of the metering pump.
Such a metering pump according to the invention further makes it possible to quickly and efficiently change out those parts of the pump having moveable parts and therefore requiring maintenance without having to break down a metering device 4 consisting of several stacked metering pumps, as is the case with the prior art. The supply of lubricant and the pneumatics must merely be interrupted temporarily and the delivery lines disconnected. The pump block is then removed from the mounting block and a new pump block with fresh sealing elements is inserted. Upon connection of the delivery line and opening of the feed lines, the metering device can immediately be put back into operation. The removed pump block can then be subsequently inspected or repaired separately.
The inventive configuration of the metering pump also offers the advantage that existing metering devices can be retrofitted with inventive metering pumps if they are compatible in terms of the dimensioning of the mounting blocks and the connection elements. When breaking down a lubricant metering device according to the prior art (like in FIG. 2, for example), a defective metering pump can be replaced by a metering pump according to the invention. If it needs to be checked later, it is no longer necessary to break the stack down, however, but rather the pump block is merely exchanged.
In an alternative configuration, the first feed duct system of the pump block could also be embodied as a blind hole instead of as a continuous hole. A single opening that is connected to the groove is substantially sufficient in order to ensure the feeding of lubricant into the metering chamber. However, the use of a continuous duct offers the advantage that the ventilation functions better upon the initial filling of the metering pump.
In the example shown in FIG. 12 of a metering pump according to the invention, the pump block 10 is not fixed in the longitudinal direction 101, which is also not necessary, since no forces occur in the longitudinal direction between the pump block and the mounting block. The longitudinal-side stop 314 ensures correct positioning. In another version, however, fixing means 34 can be provided in order to attach the pump positively and/or nonpositively in the mounting block. For example, a cap nut or similar means can be provided at the first opening 312 in order to block the pump block in the receptacle 31.
Likewise, the pump block and mounting block can be provided with a bayonet coupling mechanism, or the pump block is secured with a Seeger ring.
FIG. 5 shows another possible variant for the fixation of the pump block 10 in the mounting block 30, in a longitudinal section through the rear end of the metering pump. In this exemplary embodiment, the connection piece 451 is provided with a continuous external thread that is screwed into the pump block on one end. Also arranged on the external thread is a nut 452 that is supported on the rear end of the mounting block, thus fixing the pump block in a positive manner in the receptacle of the mounting block.
FIG. 6 shows an embodiment of a metering pump 1 according to the invention in which a screw 341 is provided in a slotted hole 343 in the side wall of the mounting block 30 that is capable of engaging in a circumferential groove 342 in the pump block provided for this purpose in order to positively fix the longitudinal position of the pump block 10 in the receptacle 31. FIG. 6 shows a cross section in the area of the actuator cylinder 162 through the circumferential fixing groove 342. Such a solution is especially advantageous, since it is space-saving and cost-effective. The groove 342 makes it possible to mount the pump block in the mounting block without exact angular orientation.
The fixing screw 341 is advantageously made of a stable plastic or a soft metal. This is sufficient for the positive fixation. At the same time, if the pump block is not inserted completely into the mounting block, the fixing screw 341 is prevented from being pressed into the cylindrical cover and deforming and damaging the latter. Since a screw 341 made of plastic or soft metal has a lower hardness than the cylindrical cover of the pump block, the screw is deformed instead.
FIG. 7 shows a schematic view of a variant of a metering pump according to the invention in which the circumferential grooves are arranged on the cylindrical cover 15 of the pump block. Such a variant offers the advantage over the embodiment from FIG. 2 that the mounting body is simpler to manufacture.
FIG. 8 shows another advantageous embodiment of an inventive metering pump 1 in which a third 51 and a fourth 52 circumferential groove are arranged on the lateral surface 311 of the receptacle 31. The third groove 53 is connected to a pump duct 13′ arranged in the side wall of the mounting block 30 for the lubricant to be pumped, which pump duct 13′ is connected to the delivery line (not shown). The pump duct 13 in the pump body opens on two sides toward the groove 51. Such a configuration of the metering pump 1 makes it possible to arrange the connection for the delivery line on the mounting block 30 instead of on the pump block 10. Accordingly, when the pump block 10 is changed out, the delivery line 45 no longer needs to be disconnected, which further simplifies the exchange.
The fourth groove 52, in turn, is connected to a vent duct 53 in the side wall of the mounting blocks 30, which is open to the outside. The pump block 10 has one or more holes 54 that open on the lateral surface 15 toward this fourth groove 53 and are connected to the volume opposite the pressurized side of the cylinder 162. This offers the advantage that the actuator piston 163 always works against external pressure, so no relevant counterpressure occurs when the piston moves, and no warming occurs. In an advantageous variant, the groove 53 can simultaneously be used as a fixing groove 342 for a fixing screw 341 as shown in FIG. 6.
The vent ducts 53, 54 are connected in a sealing manner by sealing elements 521, 521′ circumferentially arranged on the cover 15, the sealing elements 521′, 331 being identical. Analogously, the sealing elements 511, 511′ connect the delivery channels 13′, 13. An opening in the longitudinal-side end of the mounting block serves to ventilate the interior of the mounting block upon insertion of the pump block.
FIG. 9 shows the pump block 10 of another advantageous embodiment of an inventive metering pump 1 which has a similar construction as the metering pump from FIG. 8. The openings of the feed duct 11 for the liquid, of the feed duct 17 for the pressurized air, of the vent duct 54 and of the pump duct 13 are arranged on a line. The individual sealing elements are not shown so that the corresponding grooves in the cover 15 of the pump block 362, 362′, 522, 512 are visible. Only one sealing element is provided for the pump duct 13 and is arranged in the groove 512. As will be explained below in relation to FIG. 10, this is sufficient for the seal, since the longitudinal-side end of the receptacle of the mounting block 30 has a closed design.
The depicted pump block 10 can be built into a mounting block 30 according to FIG. 10, for example. In this example, the vent duct 53 and the pump duct 13′ open toward a first side wall 301 of the mounting block. The feed duct 35 for the pressurized air is arranged parallel to the feed duct 32 for the lubricant but does not run through the longitudinal axis 101, but rather intersects tangentially with the groove 36. A branch 35′ of the feed duct 35 opens toward a second side wall 301′ of the mounting block 30. A feed line of a pressurized air pulse generator can be connected to the corresponding connection opening. The corresponding air pulse can thus be forwarded via the feed duct 35 to the adjacent metering pumps. If the connection 35′ is not needed, for instance because the pressurized air pulse is being delivered from another metering pump, then the opening 35′ can be tightly sealed off by means of an appropriate closure element (not shown).
Another advantage of the depicted mounting block 30 is an advantageous, novel connection 41 of the individual metering pumps into a stack. For this purpose, two T-shaped recesses 416 are provided on both side walls for a clip 412. The corresponding clip 412 is shown in FIG. 11. In order to positively and nonpositively connect two metering pumps stacked one on top of the other, the clip 412 is screw-connected with both mounting blocks 30. Corresponding holes 419 and threaded holes 418 are provided on the mounting block and on the clip. Here, the clip is advantageously dimensioned such that, upon screwing, force is applied in the longitudinal direction of the clip which braces the two mounting blocks against each other. Accordingly, the clamping bolts used in the prior art can be omitted, which reduces the space requirements of a lubricant metering device according to the invention compared to the prior art.
If the external dimensions of such a metering pump according to the invention are appropriately selected, however, then it is also compatible with the conventional attachment system with clamping bolts, so existing lubricant metering devices can be retrofitted, for example, with individual metering pumps according to the invention.
FIG. 12 shows a special variant of such a mounting block 30. This mounting block has on its upper wall 302 a connector 431 for a corresponding connection element (not shown) of a lubricant supply unit. This connector is connected to a feed duct that is arranged tangentially to the groove 36, it being possible to reversibly interrupt this connection by means of a stop valve in the form of a shut-off valve 44.
FIG. 13 shows such an inventive metering device 4 with a lubricant supply unit with reservoir 43, as well as one inventive metering pump 1, 1 a from FIG. 12 and FIG. 15 in a stacked arrangement. The reservoir 43 is a reservoir that is substantially known from the prior art for minimum-quantity cooling lubrication, with appropriate venting and filtering devices, etc., which need not be discussed here in further detail. A feed line 46 leads to a connection piece 432 that is screwed into the corresponding connection opening 431 of a metering pump 1 according to FIG. 15. Das shut-off valve 44 separates the reservoir 43 from the feed duct system 32. A second metering pump 1 a according to FIG. 12 is connected to the first metering pump 1 by means of two clips 412. In turn, this second metering pump 1 a is sealed on its lower wall 303 with a closure block 414. In the example shown, this closure block is screwed into corresponding holes 314 of the metering pump 1 a. Alternatively, clips can also be used.
During normal operation, the shut-off valve 44 is constantly open. When a pump block needs to be exchanged, then the shut-off valve 44 is closed after the pressure pulse generators (not shown) are shut off. The pump block can be removed without having to empty the lubricant feed duct system 32. After insertion of the new pump block, the valve 44 must only be opened again and the metering device 4 according to the invention is again ready for operation.
Another variant of such a mounting block 30 is disclosed in FIG. 14. In this advantageous embodiment, the mounting block 30 has two receptacles 31, 31 a for two pump blocks. Each of the two receptacles 31, 31 a has its own connector 35′ for the pressurized air feed. Accordingly, the pressurized air can be [supplied] via one of these two connectors, the other being sealed. Both connectors can also be sealed, so that the pressurized air feed is provided by an adjacent mounting block via the feed duct system 35.
Accordingly, such a mounting block 30 can also be implemented with a connector 431 for the lubricant feed, as shown in FIG. 15.
In another advantageous embodiment, a special connection block is provided for the lubricant feed in which a connection opening 431 for a feed duct system 32 is provided that can be closed by a shut-off valve 44. Analogously to the mounting blocks discussed above, the feed duct system can be connected to the feed duct system from additional mounting blocks. Accordingly, such an advantageous connection block offers special advantages not only for metering devices with inventive metering pumps, but also for metering devices with cuboid-shaped metering pumps according to FIG. 2. In both cases, such an inventive connection block makes it possible to change out metering pumps without having to remove the lubricant container, given that the supply is disconnected using the shut-off valve 44.
The content of all of the documents cited in this application constitutes, by reference, an integral component of the disclosure.
The disclosed specific embodiments are not intended to limit the scope of the present invention. For the person skilled in the art, various possible variations and modifications in addition to the disclosed examples follow from the above description and the drawings that also fall under the scope of protection of the claims.

LIST OF REFERENCE SYSTEM

1, 1 a, 1 b, 1 c metering pump
10, 10 a pump block
101 longitudinal axis
102, 102′ side wall
103 recess for sealing element
104 sealing element, sealing ring
11, 11 a first feed duct system for liquid
111, 111′ opening
12 metering chamber, metering cylinder
13, 13′ pump duct
131 stop valve
132 return spring of the stop valve
14 metering piston
141 front end of the piston
142 axis of the metering piston
15 housing cover, housing
16 actuator device
161 return element, return spring
162 cylinder of the pneumatic actuator device
163 piston of the pneumatic actuator device
164 adjustment threads for metering piston position
165 rotating knob, manual operation
17 second feed duct system for pressurized air
171, 171′ opening
21 liquid, lubricant
22 pressurized air, pneumatic medium
30, 30 a, 30 b mounting block
301, 301′ side wall
302 upper wall
303 lower wall
304 blind hole with internal threads
31, 31 a receptacle
311 wall of the receptacle
312 insertion opening
313 second opening
314 stop
32, 32 a third feed duct system for liquid
321, 321′ opening
33 first circumferential groove for liquid
331, 331′ sealing element, sealing ring
332, 332′ recess for sealing element
34 fixing means
341 screw
342 groove
343 threaded hole
35, 35′, 35 a fourth feed duct system for pressurized air
351, 351′ opening
36 second circumferential groove for pressurized air
361, 361′ sealing element, sealing ring
362, 362′ recess for sealing element
4 lubricant metering device
41 connection means
410 clamping bolts
411 nut
412 clip, bracket
413 clamping plates
414 closure block
415 connection block
416 recess for clip, bracket
418 blind hole with internal threads
419 hole
42 pump stack
421 axis of the pump stacks
43 reservoir
431 mounting opening for connection element
432 connection element
44 shut-off valve
441 mounting opening for shut-off valve
45 delivery line for the lubricant
451 connection piece delivery line
452 nut
46 feed line
51 third circumferential groove
511, 511′ sealing element, sealing ring
512, 512′ recess for sealing element
52 fourth circumferential groove
521, 521′ sealing element, sealing ring
522, 522′ recess for sealing element
53 vent duct
54 vent duct

Claims

1. A metering pump for metering liquids, with at least one pump block comprising:

a first feed duct system for the liquid to be delivered; a pump duct; and

a pump device for pumping the liquid from the feed duct system into the pump duct,

wherein the pump block has a housing cover in the form of a cylinder or of a truncated cone, the feed duct system leading to at least one opening arranged in the housing cover.

2. The metering pump as set forth in claim 1, wherein the pump device has a metering chamber connected to the first feed duct system, a metering piston arranged in the metering chamber so as to be slidable along an axis, and an actuator device for moving the metering piston along said axis, the metering piston being set up to pump a certain quantity of a liquid present in the metering chamber through a stop valve into the pump duct when moved in a direction along said axis.

3. The metering pump as set forth in claim 1, characterized-by further comprising:

a pneumatic actuator device operable by a pneumatic medium, particularly pressurized air, and a second feed duct system for the pneumatic medium for operating the pneumatic actuator device, said second feed duct system leading to at least one opening arranged in the housing cover.

4. The metering pump as set forth in claim 1, further comprising:

a mounting block with at least one receptacle that is adapted to the shape of the housing cover of the pump block and in which the pump block is arranged in a flush-fitting manner.

5. The metering pump as set forth in claim 4, further comprising:

a circumferential groove, on the housing cover of the pump block, as well as a screw arranged in a continuous threaded hole in the mounting block, the groove, the threaded hole and the screw being embodied and arranged such that, in an assembled pump block, the screw can reversibly engage with the groove, thus enabling the reversible positive fixation of the pump block in the mounting block in the direction of the longitudinal axis.

6. The metering pump as set forth in claim 4, wherein the mounting block has a third feed duct system for the liquid; and

a first circumferential groove is provided on the wall of the receptacle connected to the third feed duct system and arranged such that the at least one opening of the first feed duct system of a pump block arranged in the mounting block overlaps with the first circumferential groove; or

that the third feed duct system leads to at least one opening arranged in the wall of the receptacle, and a first circumferential groove is provided on the housing cover of a pump block arranged in the mounting block that is connected to the first feed duct system and arranged such that the at least one opening of the third feed duct system overlaps with the first circumferential groove;

so that the first and third feed duct systems form a continuous feed duct system for liquid.

7. The metering pump as set forth in claim 6, wherein the mounting block has a fourth feed duct system for pneumatic medium; and

a second circumferential groove is provided on the wall of the receptacle is connected to the fourth feed duct system and is arranged such that the at least one opening of the second feed duct system of a pump block arranged in the mounting block overlaps with the second circumferential groove; or

that the fourth feed duct system leads to at least one opening arranged in the wall of the receptacle, and a second circumferential groove is provided on the housing cover of a pump block arranged in the mounting block that is connected to the second feed duct system and arranged such that the at least one opening of the fourth feed duct system overlaps with the second circumferential groove;

so that the second and fourth feed duct system form a continuous feed duct system for pneumatic medium.

8. The metering pump as set forth in claim 6, characterized by further comprising:

sealing elements that are arranged at least one of in the receptacle of the mounting block and around the housing cover of the pump block along the periphery and are capable of connecting in a sealing manner the at least one opening of the first feed duct system or at least one of the third feed duct system and the first circumferential groove and of connecting in a sealing manner the at least one opening of the second feed duct system or of the fourth feed duct system and the second circumferential groove.

9. The metering pump as set forth in claim 4, wherein the mounting block has two parallel flat walls and at least one of the third feed duct system and the fourth feed duct system leads to an opening on both walls, the corresponding two openings being arranged such that one opening coincides with a corresponding opening of another, equivalent metering pump when the two metering pumps are placed with their walls one on top of the other.

10. The metering device for metering liquids, with at least one metering pump as set forth in claim 1.

11. The metering device as set forth in claim 10, wherein two or more metering pumps have a mounting block with a receptacle that is adapted to the shape of the housing cover of a pump block of the metering pump and in which the pump block is arranged.

12. The metering device as set forth in claim 11, wherein the two or more metering pumps are arranged in a stack, wherein two parallel, flat walls of each of the mounting blocks of two adjacent metering pumps lie flush one on top of the other.

13. The metering device as set forth in claim 12, further comprising:

a reservoir for the liquid, a common feed duct system of the metering pumps for the liquid, and

a shut-off valve for the reversible disconnection of the feed duct system from the reservoir.

14. The metering device as set forth in by claim 10, further comprising:

a device for the detachable connection of the mounting blocks of two adjacent metering pumps, that are functionally connected to the mounting blocks to be connected.

15. The metering device as set forth in claim 14, wherein the device is embodied such that, when the functionally connection of the device to the mounting blocks to be connected is established, the mounting blocks are braced against each other.