Hydraulic device with a lubricating pump

The invention relates to a hydraulic device, in particular a hydraulic percussion device, with a supply for a pressurized hydraulic fluid, for example hydraulic oil, and with a pressurized lubricating pump connected according to the flow with a supply through a hydraulic inlet, and having a pump element for pumping lubricating grease, e.g. solid grease, from the reservoir to at least one supplied with lubricant, lubrication point of the hydraulic device and means for producing pump stroke of the pump element.

[0002] DE 20 2004 019 503 U1 describes a pressurized lubrication pump, for example for a hydraulic portable hammer, in which a hydraulic oil or the like used for operating a hydraulic portable hammer acts on a control piston with a small piston surface connected with a follower piston with a large piston surface that pumps the lubricant to at least one lubrication point of the hydraulic portable hammer. Through this differential piston system, hydraulic oil, which is usually at very high pressure, used for operating a portable hydraulic breaker, can be used to pump the lubricant at clearly lower pressure.

[0003] Furthermore, from US 6,736,292 B2 a motor is known, operated with compressed air, which can be used to pump the lubricant from the cartridge to the lubrication point. At the same time, the engine has a piston system, slidable by compressed air by spring force, slidably positioned, oscillating in the hull and thereby producing pump stroke of the pump element.

[0004] US 4,352,644 and 6,494,347 B1 show and describe in each case pneumatic lubrication devices. In detail, US 6,494,347 discloses a lubrication gun having an automatic continuous feed device whose piston can be moved on both sides and automatically. The piston movement is over-controlled by the fact that at the end of the forward movement, the seal enters a recess in its piston housing. As a result, the expansion valve opens and the piston pressure equalizes. As a result, the piston can be moved back by the force introduced by the spring. The hydraulic pump disclosed in US 4,352,644 has a piston moving back and forth, moved in one direction by the delivery fluid and in the other direction by the spring.

[0005] The pressurized lubrication pump disclosed in US 2,861,519 has a main piston driving the pump as required. The piston oscillates until solid lubricant or other lubricant is pumped through the pump or it rests in equilibrium. The movement of the piston is caused by the control valve and by means of rocking levers located at the ends of the control valve.

[0006] The object of the present invention is to provide a hydraulic device of the kind mentioned at the outset with a pressure lubrication pump, which is characterized by high reliability with a simple operation method and inexpensive production.

[0007] This task is solved by a device having the features of claim 1.

[0008] The task is solved according to the invention essentially in that a piston subassembly is provided as a means for producing a pump stroke to which the means for overdirecting the direction of movement of at least one element of the piston subassembly with at least one bypass, formed in particular by at least one groove recess and at least one

The elastic element acting on the piston assembly in the first direction facing the hydraulic inlet, that the piston assembly is oscillating between the closed position, blocking the fluid connection between the hydraulic inlet and the hydraulic outlet and the opening position releasing this fluid connection in the body to produce pump stroke. In this way it is possible to use a pressurized hydraulic fluid driving, for example, a portable hydraulic hammer, also for forcing the lubricant to the lubrication points of the hydraulic device.

[0009] According to the invention, the overdrive means have a first bypass and a second bypass, which are made spaced apart, especially as grooved recesses. The first bypass can be assigned to a piston subassembly to introduce movement of the piston subassembly element relative to the next piston subassembly element, while the second bypass allows the end position of the piston system to be reached. Compared to engines or the like having only one bypass, the design of the piston component can be significantly shortened with this configuration.

[0010] Preferably, in the body of the lubricating pump under pressure, a first empty space is defined, divided into two chambers by a piston assembly sliding in it, whose first chamber is optionally connected via a valve and / or a throttling device with a hydraulic inlet and whose second chamber possibly connected via a valve and / or throttling device to a hydraulic outlet. By supplying the hydraulic inlet with a hydraulic fluid, also used for operating a hydraulic percussion device or the like, the piston subassembly thus shifts with the force of the elastic element in the body. In this way, the piston component also acts on the pump element or supply piston, so that the lubricant is pumped to the lubrication point.

[0011] The piston subassembly preferably has an external piston, guided in a first empty space of the body, with a second hollow space defined therein, and an internal piston, guided in this second empty space. In this case, a third void is defined between the outer surface of the outer piston and the inner surface of the body, which is in fluid communication with the second empty space. This configuration of the piston subassembly makes it possible to create a fluid connection between the side facing the hydraulic inlet and the side of the piston assembly facing the hydraulic outlet, thereby allowing overloading of the piston subassembly.

[0012] If at least two spaced apart sealing elements are provided on the outer surface of the outer piston, then the third cavity can be sealed relative to the first cavity, i.e. relative to both chambers divided by the piston assembly.

[0013] Overclocking of the piston subassembly can be achieved by the fact that the inner piston is slidable in the outer piston between the closed position blocking the fluid connection through the piston subassembly between the side facing the hydraulic inlet and the side of the outer piston facing the hydraulic outlet and the opening position releasing it's a fluid connection. In other words, the piston assembly moves in the first direction by the force of the hydraulic fluid and the restoring force of the elastic element when the piston assembly is in its closed position, while the piston assembly can be moved back in the opposite direction by the restoring force of the elastic element when the assembly piston is in its open position.

[0014] In order for the hydraulic fluid pressure not to be too strong when the piston subassembly and the rearward movement of the elastic element, the overloading and reverse movement of the piston subassembly must take place as quickly as possible. For this purpose, it is provided that at least two springs acting on these pistons, in particular the external piston, are assigned to the piston subassembly towards the side facing the hydraulic inlet. These springs allow the fluid connection to be quickly closed by the piston subassembly and displacement of the piston subassembly towards the side facing the hydraulic inlet.

[0015] According to a preferred embodiment of the invention, the third cavity and the first chamber are sealed to each other by an external piston and a seal provided thereon and are connected by a first bypass, opening by sliding the external piston in the first empty space. Opening the first bypass introduces overload and reverse movement of the piston subassembly. By placing the first bypass, the stroke length of the piston subassembly is thus determined during operation.

[0016] To achieve complete closing of the fluid passage through the piston assembly, the third cavity and the second chamber are sealed to each other by the outer piston and the seal provided thereon and are connected by a bypass, opening by sliding the outer piston in the first cavity.

The first bypass can be formed by a first groove recess in the inner surface of the body. The bypass connecting the third void and the second chamber may also be formed by a first grooved recess in the inner surface of the body or alternatively to this by a second grooved recess in the inner surface of the body which is positioned away from the first groove recess.

[0018] The pumping of lubricant to the lubrication point of the hydraulic device is caused by the fact that the pump element in the channel to which the inlet has an outlet, connected according to the flow with the reservoir, is guided in a sealed and sliding manner in the body. A non-return valve is provided in the duct on the side facing the lubrication point, which opens when the piston assembly moves towards the hydraulic outlet and closes during the reverse stroke of the piston assembly.

[0019] Further advantages and applicability of the invention also result from the following description of the embodiments and drawing.

[0020] In the drawing they show schematically:

Fig. 1 longitudinal section through a pressure spreading pump according to a first embodiment of the invention, fig. 2 cross section through a pressure spreading pump according to fig. 1, fig. 3 another cross section through a pressure spreading pump according to fig. 1 and Fig. 4 a longitudinal section through a pressure spreading pump according to a second embodiment of the invention.

[0021] The pressure lubrication pump 1 shown in figures 1 to 3 is formed by a body shaped as a pump housing 2, enclosed by a control housing 3. In the body 2, 3, the piston assembly 4 is moved, so that the first empty space formed in the body 2,

EP 1 982 104 B1 is divided into two chambers 5a and 5b. To the right in Figure 1, the chamber 5a has an outlet through a valve 6 and a throttling device 7, a hydraulic inlet E connected to a hydraulic fluid supply under pressure to drive a portable hydraulic hammer or other hydraulic device. In the same way the left chamber in figure 1 is connected via a throttling device 8 to the hydraulic outlet A.

[0022] The piston assembly 4 is pre-stressed in the body 2 by the compression spring 9 relative to the control housing 3. In other words, the compression spring 9 acts on the piston assembly 4 in figure 1 to the right. In addition, the piston subassembly 4 is in contact with the supply piston 10, acting as a pump element, which is guided in a sealed and slidable manner in the channel 11 in the body 2. The channel 11 has an outlet for the cartridge inlet 12, which serves as a lubricant reservoir. On the left in figure 1, in the body 2, a lubricant outlet S is provided, sealed to the channel 11 by a non-return valve 13. The non-return valve 13 is here arranged to block the flow from the lubricant outlet S towards channel 11, while lubricant can flow from the cartridge 12 through the channel 11 to the lubricant outlet S. The lubricant outlet S is connected to one or more lubrication points of the hydraulic device [0023] The piston assembly 4 is formed by an external piston 14 and an internal piston 15. The external piston 14 is slidably guided in the empty space in the body 2 forming both chambers 5a and 5b and sealed with two seals 16a and 16b relative to the chambers 5a or 5b. A recess is provided between the seals 16a and 16b in the outer piston 14, so that a hollow space 17 is created between the inner surface of the body 2 and the outer surface of the outer piston

14. This hollow space 17 is connected via a channel in the outer piston 14 to another hollow space 18, guided inside the external piston 14. In the next empty space 18, the internal piston 15 is slidably guided. In this case, another channel 19 is thus arranged in the outer piston 14 that the chamber 5b facing the hydraulic outlet A is connected to another empty space 18 inside the external piston 14. However, the internal piston 15 prevents flow between the recess 17 and the chamber 5b. However, the internal piston 15 can be lifted from the valve seat provided on the external piston 14 to allow a fluid connection between the chamber 5a facing the hydraulic inlet E and the subsequent passage 19 through another cavity 18.

[0024] A groove recess 20 is provided in the inner wall of the body 2, which is made so as to form a bypass to allow fluid to pass past the seals 16a or 16b from the chamber 5a into the recess space 17 or from the empty recess space 17 to chamber 5b . As can be seen from figure 3, a safety valve 21 may be provided in the body 2.

[0025] In figure 4 another embodiment of the lubricant pump is shown. The basic structure of this lubricant pump is identical to the structure described above with reference to figures 1 to 3. However, the body dividing plane is displaced in comparison with the embodiment according to figure 1.

[0026] In addition, in the empty space forming both chambers 5a and 5b, two groove recesses 20a and 20b are provided spaced apart, the right recess 20a forming the first bypass when the piston assembly 4 is shifted to the left, that the seal 16a lies in the area of ​​the groove recess 20a. Thereby, hydraulic fluid can flow from the chamber 5a through the bypass 20a into the empty space created by the recess 17. On the other hand, the left recess 20a in the figure is positioned such that

EP 1 982 104 B1 creates a second bypass when the seal 16b is in the position shown in figure 4. By this, flow is allowed from the empty space created by the recess 17 through the bypass 20b into chamber 5b. [0027] By making a lubricant pump with two groove recesses 20a, 20b, each forming a bypass, the stroke of the piston assembly can be shortened compared to the embodiment shown in figures 1 to 3.

[0028] In the embodiment according to figure 4, the piston assembly 4 is assigned two coaxially arranged pressure springs 9a and 9b, which both act on the outer piston 14 in the figure to the right, i.e. towards the hydraulic inlet E. rapid return stroke of piston assembly 4.

[0029] Next, the operating method of the pressurized spreader will be explained in more detail. Via the hydraulic inlet E, for example, hydraulic oil is applied to the pump for pressure lubrication, also used to drive a hydraulic device not shown in the figures , e.g. a portable hammer. The hydraulic oil flows through the throttling device 7 and the anti-cancer valve 6 into the chamber 5a. The piston assembly 4 moves through the hydraulic oil pressure from the position shown in Figures 1 or 4 by the force of compression springs or 9a and 9b to the left. The throttling device 7 is preferably arranged in such a way that the piston assembly 4 only moves very slowly. The inner piston 15 is pressed into its valve seat in the outer piston 14, so that hydraulic oil cannot flow between the inner piston 15 and the outer piston 14.

[0030] The feed piston 10 in figures 1 and 4 to the left also moves through the movement of the piston subassembly 4. Thereby, the lubricant contained in the channel 11 is pumped through the non-return valve 13 to the lubricant outlet S connected to a lubricating point of a portable hammer or the like not shown. As soon as the seal 16a in figure 1 reaches the groove recess 20, the hydraulic oil also flows through the bypass formed by the groove recess 20, next to the seal 16a, into the hollow space of the recess 17 and thus also into the next empty space 18 inside the external piston 14. Through the internal piston 15 is lifted from its valve seat in the external piston 14 and moves in the figures to the right relative to the external piston 14. In the embodiment of figure 4, this bore of the internal piston 15 is achieved in the external piston 14 in that the seal 16a reaches the groove recess 20a and thus the bypass is opened.

[0031] Hydraulic oil can now flow through the passage 19 through the piston assembly 4, so that pressure equalization can occur between the chambers 5a and 5b. The springs 9 or 9a and 9b are designed in such a way that the entire piston assembly 4 moves back to the right as quickly as possible in Figures 1 to 4, whereby the internal piston 15 is also forced back relative to its valve seat in the external piston 14. In this case, the hydraulic oil in the next empty space 18 can flow through the bypass into the chamber 5b when the seal 16b reaches the groove recess 20 or 20b. It is only when the hydraulic oil is squeezed out of the next empty space 18 that the inner piston 15 can adhere sealingly to the valve seat in the outer piston 14. The supply piston 10 is also moved to the right in figures 1 and 4, so that the lubricant is sucked in cartridge 12 to channel 11. The pressure lubrication pump is thus back in its starting position, shown in figures 1 and 4, so that a new stroke of piston assembly 4 can start.

EP 1 982 104 B1

Marker list:

[0032]

<td> 1</td><td>pressure lubrication pump</td>

<td> 2</td><td>body (pump housing)</td>

<td> 3</td><td>steering hull</td>

<td> 4</td><td>piston subassembly</td>

<td>5a, 5b</td><td>chamber</td>

<td> 6</td><td>valve</td>

<td> 7</td><td>throttling device</td>

<td> 8</td><td>throttling device</td>

<td> 9</td><td>compression spring</td>

<td>9a, 9b</td><td>compression spring</td>

<td> 10</td><td>supply piston (pump element)</td>

<td> 11</td><td>channel</td>

<td> 12</td><td>cartridge</td>

<td> 13</td><td>valve</td>

<td> 14</td><td>external piston</td>

<td> 15</td><td>internal piston</td>

<td>16a, 16b</td><td>gasket</td>

<td> 17</td><td>select (empty space)</td>

<td> 18</td><td>empty space</td>

<td> 19</td><td>channel</td>

<td>20, 20a, 20b</td><td>bypass / pick</td>

<td> 21</td><td>safety valve</td>

And the hydraulic outlet

E hydraulic inlet

S lubricant outlet