|
(11) | EP 1 860 323 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
||||||||||||||||||||
| (54) | A manual pump for hydraulic circuits |
| (57) The pump comprises at least a manually-activated piston (3) which is sealedly slidable
internally of a pump chamber (4a, 4b) provided with an aspiration opening (7) and
a delivery opening (8); at least a first through-conduit (11) and at least a second
through-conduit (12) which are in communication respectively with the aspiration opening
(7) and the delivery opening (8), each of which through-conduits, at ends thereof,
terminates externally of the manual pump and is connectable to at least an external
conduit in order to define, with the external conduit, a single continuous conduit.
|
Description.
[0001] The invention relates in particular to a manual pump for a hydraulic circuit, of a type commonly used to activate lift devices using limited flow rates of operating fluid, for example the forks of a lift truck, a motor mechanics' ramp and arms for raising baskets.
[0002] These circuits generally comprise a main pump, typically activated by a motor, a reservoir for the operating fluid, a series of pipes connecting the pump and reservoir to a certain number of hydraulic actuators, constituted for example by hydraulic cylinders. A modular distributor is positioned between the main pump and the hydraulic actuators, the function of which is to controlledly distribute the operating fluid to the various actuators depending on the various operative sequences the actuators are to be activated in. The modular distributor is thus named because it is made up of a plurality of inter-connected single distributors. The number of single distributors, each of which is deputed to the control of an actuator, can vary according to the number of actuators which have to be activated by the circuit.
[0003] The single distributors exhibit a standardised exterior conformation, so as to be easily mountable and dismountable with respect to the modular distributor. Generally the single distributors are provided with at least two openings for the actuators, predisposed to connect with external conduits which connect the distributor to an actuator (there are two openings because the actuators are usually double-acting). The single distributors are further provided with a load opening, through which the pressurised fluid is sent towards the actuator, and a discharge opening, through which the fluid returns from the actuator. Between the actuator openings and the inlet and outlet openings there is a slidable obturator, which on command either disconnects or alternatively places in connection the inlet opening and the outlet opening with the openings for the actuators. The actuator is usually electromechanically controlled. A first and a second through-conduit, respectively connected with the inlet opening and the outlet opening, are arranged through each single distributor. Each of the through-conduits, at ends thereof, terminates externally of a respective single distributor in such a way that, when the single distributors are placed side-by-side and connected up, two continuous conduits are established through the distributor group. The load openings of the respective distributors are connected in succession to one of the continuous conduits, which the discharge openings of the single distributors are connected to the other continuous conduit.
[0004] Hydraulic circuits of this type further comprise another fundamental component constituted by a manual pump. This is generally activated by a lever and is required for performing certain smaller operations, such as for example lowering a platform or a basket blocked in raised positions, in the case of a fault in the main pump.
[0005] Manual pumps on the market are in the form of a element which is separate from the other components of the circuit, and which required its own circuit connector conduits. Apart from these dedicated conduits, known-type manual pumps also need a certain degree of space for activation of the control lever. This often constitutes a serious problem in that the spaces dedicated to these circuits are rather restricted and the location of the manual pump is decidedly out of harmony with the compactness needed by the circuits.
[0006] The main aim of the present invention is to provide a compact pump whose connection to a hydraulic circuit can occur without any need for providing pipes dedicated exclusively to the connection.
[0007] Further characteristics and advantages of the invention will better emerge from the detailed description that follows, made with reference to the accompanying figures of the drawings, given by way of non-limited example, in which:
figure 1 shows a plan view of a modular distributor incorporating a pump of the present invention;
figure 2 is a section view of the modular distributor of figure 1 made according to line II-II of figure 1;
Figure 3 is a manual pump as in the present invention in a section view made following line III-III of figure 2;
Figure 4 is a diagram of the distributor of figure 1.
[0008] With reference to the figures of the drawings, the manual pump 1 of the invention comprises an external casing 2 in which at least a manual pump 3 is sealedly mobile internally of a pump chamber 4a, 4b.
[0009] The pump 3 is preferably though not exclusively constituted by a piston which can be single- or double-acting.
[0010] In the preferred embodiment the pump chamber 4a, 4b is open at one end towards the outside of the casing 2. The piston 3, at a portion of end 3a, projects from the pump seating and rotatably connects with an activating lever 5 arranged transversally with respect to the piston 3. At an end 5a thereof the lever 5 further exhibits a pivot which rotates with respect to the external casing 2, located on a connection element 6 between the lever 5 and the external casing 2. The rotation axes of the lever 5 with respect to the piston 3 and the external casing 2 are parallel and perpendicular with respect to the piston run direction. In this way by alternatingly oscillating the lever 5 about the fixed fulcrum thereof the piston 3 can be alternatingly slidingly activated.
[0011] The pump chamber in which the piston 3 slides is subdivided by the piston head itself into a cylindrical potion 4a and an annular portion 4b. The pump chamber is further provided with an aspiration opening 7, connected with the cylindrical portion 4a and a delivery opening 8, connected to the annular portion 4b. In a known way, the alternating slide of the piston 3 determines an aspiration of fluid internally of the pump chamber through the aspiration opening 7 and the delivery of the pumped fluid through the delivery opening 8. In more detail, with reference to figure 3, the piston 2 is provided with a channel 3b which places the cylindrical portion 4a and the annular portion 4b of the pump chamber in communication. The channel 3b is provided with a first single-acting valve 9 which enables passage of the fluid only in the direction going from the cylindrical portion towards the annular portion of the pump chamber. A second single-acting valve 10 is located at the aspiration opening 7 and enables a flow of fluid only in inlet to the cylindrical portion 4a of the pump chamber. When the piston slides from left to right, the cylindrical portion 4a of the pump chamber increases in volume and recalls fluid internally thereof through the aspiration opening 7. At the same time the fluid present internally of the annular portion 4b is expelled through the delivery opening 8. When the piston slides from right towards the left, the fluid in the cylindrical chamber 4a if forced to flow towards the annular chamber 4b through the channel 3b of the piston.
[0012] The manual pump of the present invention further comprises at least a first 11 through-conduit and at least a second 12 through-conduit which are in communication respectively with the aspiration opening 7 and with the delivery opening 8. Each through-conduit, at ends thereof, terminates externally of the manual pump in order to connect to at least an external conduit and define there-with a single continuous conduit. The presence of the two through-conduits 11, 12 and the fact that they terminate externally of the manual pump, and in particular the external casing 2, enables the manual pump to be mounted directly on any circuit comprising at least a loading branch 30 and at least a discharge branch 31, as can be seen in figure 4, without there being any need for further conduits for connecting up to the circuit. The loading branch of the circuit is preferably connected to the delivery of a main pump, while the discharge branch 31 is connected to a reserve tank for the operating fluid. The first through-conduit 11 is inserted in the discharge branch 31 forming a tract, while the second through-conduit 12 is inserted on the loading branch, forming a tract thereof. If the main pump should be faulty, activation of the manual pump 1 enables a resetting to a minimum circuit operating level. The manual pump 1 enables aspiration of fluid from the discharge branch 31 through the first through-conduit 11 and also enables pressurised fluid to be sent to the loading branch 30 in the absence of the main pump, through the second through-conduit 12.
[0013] The first through-conduit 11 and the second through-conduit 12 preferably terminate on opposite surfaces 2a, 2b of the external casing 2 of the manual pump. The external casing 2 is conformed to be directly associable, in particular at the opposite surfaces on which the first and second through-conduits 11, 12 open, to two further components of a hydraulic circuit, each of which, is preferably provided with at least two through-conduits.
[0014] As can be seen in figure 2, the conformation of the external casing 2 and the arrangement of the through-conduits is such that the first and second through-conduits 11, 12 connect at ends thereof to the through-conduits of the further components of the circuit and define, with the through-conduits of the further components, two continuous conduits. Thanks to this, the manual pump of the invention becomes, in effect, a modular element which can be flanged to other components, and especially can be inserted into an electrically- or manually-controlled modular distributor of a type which will be better described herein below.
[0015] The modular distributor, illustrated in figures 1 and 2, preferably comprises at least a first distribution valve 13, of known type and illustrated schematically in figure 4, provided with at least two connection openings 14, 15, predisposed for connection with external conduits, and exhibiting a load opening 16 and a discharge opening 17. A slidable obturator, not illustrated as of known type, on command disconnects or connects up alternatingly the load opening 16 and the discharge opening 17 with the connection openings. The first distribution valve 13 is a four-way three-position valve in which the connection openings 14, 15 are predisposed to be connected to a hydraulic actuator.
[0016] The first distribution valve further comprises a first and a second through-conduit 18, 19, respectively connected to the discharge opening 17 and the load opening 16. Each of the through-conduits 18, 19 terminates externally of the distribution valve 13.
[0017] The architecture of the first distribution valve 13 reflects that of the manual pump 1. The presence of the two through-conduits 18, 19 and the fact that they terminate externally of the distribution valve 13, enable the valve to be mounted directly on the circuit of figure 4. The first through-conduit 18 is inserted in the discharge branch 31, forming a tract thereof, while the second through-conduit 19 is inserted on the loading branch, forming a part thereof. In this way, pressurised fluid can always be sent to the load opening 17 of the distribution valve 13, from the main pump or the manual pump 1. The discharge opening 16 is, on the other hand, always connected to the discharge branch 31 by the first through-conduit 18.
[0018] The distribution valve 13 is preferably a common-type modular element, the size of which and its external conformation are standard. These valves are generally used for realizing modular distributors in which a determined number of valves, each of which is connected to a hydraulic actuator, are connected up one to another.
[0019] The modular distributor of the invention comprises a manual pump 1 associated to the first distribution valve 13 in such a way that the first and second through-conduits 11, 12 of the manual pump 1 are connected at a respective end thereof with the first and second through-conduits 18, 19 of the distribution valve 13. The modular distributor of the present invention preferably comprises one or more further distribution valves 13a, 13b, each of which is provided with a first through-conduit 18a, 18b and a second through-conduit 19a, 19b. The other distribution valves 13a, 13b are associated in succession to the first distribution valve 13 on the opposite side with respect to the manual pump 1 so that the through-conduits of the manual pump 1 and the distribution valves 13, 13a, 13b define two continuous conduits.
[0020] The modular distributor illustrated in figures 1 and 2 is completed by at least an inlet component 20 provided with a first through-conduit 21 and a second through-conduit 22. The inlet component 20 is associated to the manual pump 1 in such a way that the first and second through-conduit 11, 12 of the manual pump 1 and the first and second through-conduit 21, 22 of the inlet component 20 are reciprocally connected at an end thereof, so as to define two continuous conduits. Advantageously the inlet element 20 can be provided with a pressure-limiter valve for controlling the pressure in the second through-conduit 22, which can be connected to the main circuit pump, while the first through-conduit 21 can be connected to the reservoir.
[0021] As can be seen in figure 2, the modular distributor exhibits a first continuous conduit, made up of the first through-conduits 21, 11, 18, 18a, 18b of the various components, which can be inserted in the discharge branch 31 of the circuit in order to constitute a continuous tract of the discharge branch 31. The distributor further exhibits a second continuous conduit, made up of the second through-conduits 22,12,19,19a,19b of the various components, which can be inserted in the load branch of the circuit so as to constitute a continuous tract of the loading branch 30 itself. When the main pump is operating, the pressurised fluid arrives at the various distribution valves 13,13a,13b through the second continuous conduit 22,12,19,19a,19b. The manual pump does not interact operatively with the pressurised fluid which simply transits through the second through-conduit 12 of the manual pump. In the case of a main pump breakdown, the activation of the manual pump 1 enables sending pressurised fluid to the distribution valves through the second through-conduit 12 of the manual pump 1 which, as mentioned, is connected to the second conduits 19,19a,19b of the distribution valves 13,13a,13b. When the main pump is functioning, the fluid returns to the circuit reservoir through the first through-conduits 18b,18a,18,11,21. When the manual pump 1 is working, the fluid returning from the distribution valves along the first conduits 18b,18a,18 is aspirated by the manual pump through the aspiration opening 7 which is in communication with the first through-conduit 11, so that the circuit closes internally of the manual pump 1.
1. A manual pump for hydraulic circuits, comprising at least a manually-activated pump
(3) which is sealedly mobile internally of a pump chamber (4a, 4b) provided with an
aspiration opening (7) and a delivery opening (8), characterised in that it comprises at least a first through-conduit (11) and at least a second through-conduit
(12) which are in communication respectively with the aspiration opening (7) and the
delivery opening (8), each of which through-conduits, at ends thereof, terminates
externally of the manual pump and is connectable with at least an external conduit
in order to define, with the external conduit, a single continuous conduit.
2. The manual pump of claim 1, wherein the at least a first through-conduit (11) and
the at least a second through-conduit (12) terminate on opposite surfaces (2a, 2b)
of an external casing (2) of the manual pump.
3. The manual pump of claim 2, wherein the external casing (2) is conformed so as to
be directly associable to two further components of a hydraulic circuit.
4. The manual pump of claim 3, wherein the external casing (2) is directly associable
to the further components of the hydraulic circuit at opposite surfaces (2a, 2b) of
the casing (2), on which the at least a first and the at least a second through-conduits
(11, 12) terminate, in order that the at least a first and the at least a second through-conduit
(11, 12) of the manual pump (1) connect by ends thereof to a respective through-conduit
of the further components and define, together with the through-conduits of the further
components, two continuous conduits.
5. An electrically or a manually-controlled modular distributor, comprising at least
a first distribution valve (13) provided with: at least two connection openings (14,
15) for connection thereof with external conduits; a load opening (16) and a discharge
opening (17); a sliding obturator which, on command, disconnects or alternatingly
connects the inlet opening and the outlet opening with the connection openings (14,
15) for connecting with external conduits; a first and a second through-conduit (18,
19), respectively connected with the load opening (16) and the discharge opening (17),
each of which through-conduits, at ends thereof, terminates externally of the distribution
valve (13), characterised in that it comprises a manual pump (1) as in claim 4, associated to the first distribution
valve (13) in order that the at least a first through-conduit (11) and the at least
a second through-conduit (12) of the manual pump (1) are connected at an end thereof
with the first and the second through-conduit (18, 19) of the distribution valve (13).
6. The modular distributor of claim 5, wherein one or more further distribution valves
(13a, 13b), each of which is provided with a first through-conduit (18a, 18b) and
a second through-conduit (19a, 19b); are associated in succession to the first distribution
valve (13) on an opposite side with respect to the manual pump (1) so that the through-conduits
of the manual pump (1) and the distribution valves (13a, 13b) define two continuous
conduits.
7. The distributor of claim 5 or 6, wherein at least an inlet element (20), provided
with a first (21) and a second (22) through-conduit, is associated to the manual pump
(1) in such a way that the at least a first through-conduit (11) and the at least
a second through-conduit (12) of the manual pump (1) and the first through-conduit
(21) and the second through-conduit (21, 22) of the inlet component (20) are connected
to one another at an end in order to define two continuous conduits.