WO2016001428A1

WO2016001428A1 - Telescopic hydraulic cylinder

Info

Publication number: WO2016001428A1
Application number: PCT/EP2015/065252
Authority: WO
Inventors: Giuseppe MARTINON
Original assignee: Binotto - S.R.L.
Priority date: 2014-07-04
Filing date: 2015-07-03
Publication date: 2016-01-07

Abstract

A telescopic hydraulic cylinder (10), comprising a containment jacket (11) which is closed at one end by an end plate (12), containing at least one telescopic element (13); a stroke limiting shoulder (18) is provided within the containment jacket (11) and is preset to meet a corresponding annular abutment portion (22) defined externally to the adjacent telescopic element (13); the containment jacket (11) has an inlet (26) for pressurized oil for pushing the concentric telescopic element (13); between the containment jacket (11) and the telescopic element (13) there is, between the stroke limiting shoulder (18) and the respective annular abutment portion (22), a chamber (27) for slowing the stroke of the telescopic element (13); the slowing chamber (27) has at least one hole (31) for the passage of pressurized oil defined on the corresponding telescopic element (13); between the containment jacket (11) and the telescopic element (13), at the stroke limiting shoulder (18), there is a throttling passage (35) for the pressurized oil that is preset to allow the passage of oil from the slowing chamber (27) to the corresponding oil passage hole (31) when the corresponding oil passage hole (31) is displaced with respect to the slowing chamber (27); there are also rings for throttling the oil passage section (39, 40, 41, 42), each throttling ring (39, 40, 41, 42) defining a corresponding slowing passage (70).

Description

TELESCOPIC HYDRAULIC CYLINDER

The present invention relates to a telescopic hydraulic cylinder.

Telescopic hydraulic cylinders with one or more telescopic elements are currently known and widespread, for example for lifting dump bodies on transport trucks.

These telescopic hydraulic cylinders comprise a containment jacket, which is closed at one end by an end plate and contains at least one telescopic element that is intended to exit from the containment jacket in an axial direction under the thrust of the pressurized oil; inside the containment jacket there is a stroke limiting shoulder that is intended to meet a corresponding annular abutment portion that is defined outside the adjacent telescopic element; the containment jacket is provided with an inlet for pressurized oil for pushing the concentric telescopic element.

These telescopic hydraulic cylinders, designed to lift considerable loads, on the order of tens of tons, have the severe problem of the stroke limit impact between the inner shoulder of the containment jacket and the annular abutment portion of the first telescopic element, and likewise between inner shoulders and annular abutment portions of the other telescopic elements.

This impact, repeated at each use of the cylinder, can in fact lead to failure of one of its components and certainly causes intense vibration phenomena that are transmitted from the cylinder to the entire structure of the means of transport, with particular negative repercussions on the joints and articulations by means of which the cylinder is connected at one end to the chassis of the transport vehicle and at the other end to the dump body to be lifted.

The aim of the present invention is to provide a telescopic hydraulic cylinder that is capable of obviating the cited drawback that is typical of similar known telescopic cylinders.

Within this aim, an object of the invention is to provide a telescopic hydraulic cylinder in which the stroke limit impact is reduced with respect to telescopic cylinders of the known type.

Another object of the invention is to provide a telescopic hydraulic cylinder that is capable of reducing considerably the generation of vibrations, and therefore has a reduced noise emission, during operation.

A further object of the invention is to provide a telescopic hydraulic cylinder that has a longer life and requires less maintenance than similar cylinders of the known type.

This aim, as well as these and other objects that will become better apparent hereinafter, are achieved by a telescopic hydraulic cylinder, comprising a containment jacket which is closed at one end by an end plate, containing at least one telescopic element, a stroke limiting shoulder being provided within said containment jacket and being preset to meet a corresponding annular abutment portion defined externally to the adjacent telescopic element, said containment jacket having an inlet for pressurized oil for pushing said at least one concentric telescopic element, said telescopic hydraulic cylinder being characterized in that between said containment jacket and said telescopic element there is, between said stroke limiting shoulder and said respective annular abutment portion, a corresponding chamber for slowing the stroke of said telescopic element, said slowing chamber having at least one hole for the passage of pressurized oil defined on the corresponding telescopic element, between said containment jacket and said telescopic element, at said stroke limiting shoulder there being a throttling passage for the pressurized oil that is preset to allow the passage of oil from said slowing chamber to the corresponding oil passage hole when said corresponding oil passage hole is displaced with respect to said slowing chamber.

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the telescopic hydraulic cylinder according to the invention, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

Figure 1 is a side view of a truck with a dump body that can be lifted and is provided with a hydraulic cylinder according to the invention;

Figure 2 is a longitudinal sectional view of the cylinder according to the invention in the inactive configuration;

Figure 3 is a perspective cutout view of the lower part of the cylinder according to the invention;

Figure 4 is a view of a portion of a longitudinal cross-section of a cylinder according to the invention in a first step of operation;

Figure 5 is a view of a portion of a longitudinal cross-section of a cylinder according to the invention in a second step of operation;

Figure 6 is a view of a portion of a longitudinal cross-section of a cylinder according to the invention in a third step of operation;

Figure 7 is a view of a detail of Figure 5;

Figure 8 is an enlarged- scale view of Figure 7,

Figure 9 is a longitudinal sectional view of a detail of the cylinder according to the invention in a first step of operation;

Figure 10 is the same view as Figure 9 in a second step of operation of the cylinder according to the invention.

With reference to the figures, a telescopic hydraulic cylinder according to the invention is designated generally by the reference numeral 10.

The cylinder 10 comprises a containment jacket 11, which is closed at one end by an end plate 12.

The cylinder 10 comprises for example a plurality of concentric telescopic elements, in the constructive example described herein four concentric telescopic elements 13, 14, 15 and 16, of which an outer telescopic element 13, one or more intermediate telescopic elements 14 and 15, and an inner telescopic element 16. The inner telescopic element 16 supports, externally to the containment jacket 11, a pusher head 17, which is intended for fixing to the body to be lifted, for example a dump body of a truck.

Inside the containment jacket 11 and inside each one of the outer telescopic element 13 and intermediate telescopic elements 14 and 15 there is a stroke limiting shoulder 18, 19, 20 and 21 respectively, preset to meet a corresponding annular abutment portion 22, 23, 24 and 25 that is defined externally to the adjacent outer telescopic element 13, intermediate telescopic element 14, 15, or inner telescopic element 16.

The containment jacket 11 has an inlet and an outlet 26 for pressurized oil.

Between the containment jacket 11 and the outer telescopic element 13, and between the adjacent outer telescopic element 13, the intermediate telescopic elements 14 and 15 and the inner telescopic element 16, there are, between a stroke limiting shoulder 18, 19, 20 and 21 and a respective annular abutment portion 22, 23, 24 and 25, corresponding chambers 27, 28, 29 and 30 for slowing the stroke limit impact of each telescopic element, as clearly visible in Figure 2.

Pairs of diametrically mutually opposite holes 31, 32, 33 and 34 are provided on the outer telescopic element 13, on the intermediate telescopic elements 14, 15 and on the inner telescopic element 16 in order to allow the passage of the oil through the slowing chambers to the inner central chamber 47 and vice versa.

It is understood that the through holes indicated and described here can have a circular or quadrangular or elliptical cross- section or a cross- section with other geometries depending on the needs and the technical requirements.

The through holes referenced and described herein, therefore, are not to be understood as being exclusively cylindrical.

The number of two through holes cited above is to be understood as a nonlimiting example of the invention, since as a further example there can be two pairs of opposite through holes, therefore four holes instead of the described two.

Between the containment jacket 11 and the outer telescopic element 13, between the latter and the adjacent intermediate telescopic element 14, between the intermediate telescopic elements 14 and 15 and between the inner telescopic element 16 and the intermediate telescopic element that is adjacent thereto 15, at each stroke limiting shoulder 18, 19, 20 and 21, there is a passage 35, 36, 37 and 38 respectively, for the throttling of the pressurized oil, which is intended to allow the passage of oil from the corresponding slowing chamber 27, 28, 29 and 30 to the corresponding oil passage hole 31, 32, 33, 34 when said corresponding oil passage hole is displaced with respect to the respective slowing chamber; this situation is clearly exemplified in Figures 5 and 6 and the detail of the throttling passage 35 is shown clearly in Figure 7.

The containment jacket 11, the first telescopic element 13 and the intermediate telescopic elements 14 and 15 have, proximate to the corresponding stroke limiting shoulder 18, 19, 20 and 21, and on the opposite side with respect to the slowing chamber 27, 28, 29 and 30, a ring for throttling the oil passage section, 39, 40, 41 and 42 respectively.

Each throttling ring 39, 40, 41 and 42 defines a corresponding slowing passage, which is exemplified clearly in Figure 8 and is designated therein by the reference numeral 70 with respect to a first throttling ring 39 and the adjacent outer telescopic element 13; said slowing is, for all purposes, what determines the slowing of the motion of the outer telescopic element 13 with respect to the jacket 11.

At the oil inlet/outlet 26 there are two through holes 45, 46, both for the inflow and outflow of oil, defined on the containment jacket 11.

Operation of the telescopic hydraulic cylinder 10 is as follows.

In an initial collapsed configuration, shown in Figure 2, the pressurized oil enters through the inlet 26 and, by means of two through holes 45 and 46 defined in the containment jacket 11, enters the first slowing chamber 27, defined between the containment jacket 11 and the outer telescopic element 13, and from there, by means of the corresponding opposite through holes 31, enters the second slowing chamber 28 between the outer telescopic element 13 and the first intermediate telescopic element 14; likewise, by means of the through holes 32 on the first intermediate telescopic element 14, the oil passes toward the third slowing chamber 29, and so forth until the pressurized oil reaches the inner chamber 47, pushing against the base annular surface of each telescopic element and against a central disc 48 that is arranged within the inner telescopic element 16, as shown in Figure 3.

The outer telescopic element 13 is provided with an annular resting element 49 for lifting the adjacent telescopic element 14 and, likewise, the other intermediate telescopic elements 14 and 15 are provided with corresponding annular resting elements 50, 51 to lift the adjacent more inward telescopic elements 15, 16.

The first elongation of the cylinder 10 is determined by the lifting of the outer telescopic element 13, which, by means of the annular resting element 49 for the next telescopic element 14, produces the simultaneous lifting also of said subsequent telescopic element 14 and likewise, by means of the additional corresponding annular resting elements 50 and 51, also the lifting of the other telescopic elements 15 and 16, as shown in Figure 4.

Figure 4 shows the slowing chamber 27 with the oil passage hole 31 still connected directly to the slowing chamber 27.

In Figure 5, the outer telescopic element 13 has risen further, the slowing chamber 27 has become smaller, and the oil passage hole 31 has moved with respect to the slowing chamber 27 and is no longer directly connected thereto.

In this position, the oil, pushed by the annular abutment portion 22 to move the outer telescopic element 13, still reaches the passage hole 31 through the throttling passage 35, produced by an annular interspace that is defined between the outer surface of the outer telescopic element 13 and the inner surface of the jacket 1 1, the transverse cross-section of said interspace being smaller than the corresponding transverse cross-section of the slowing chamber 27.

In particular, Figure 5 shows a situation in which the progressive overlap of the hole 31 with the throttling ring 39 forces the oil to pass through the slowing passage 70 and therefore the pressurized oil reaches the hole 31 also arranging laterally adjacent the throttling ring of the oil passage section 39, an element that indeed determines the additional throttling for the passage of oil, i.e., the slowing passage 70, which in practice slows the rise rate of the outer telescopic element 13.

The ring 39 for throttling the oil passage section is studied and provided with adapted tolerances, such as to allow the passage of oil between the ring 39 and the adjacent telescopic element, slowing the motion of the telescopic element.

In Figure 6, the slowing chamber 27 has even smaller dimensions, the annular abutment portion 22 is proximate to the stroke limiting shoulder 18, and the hole 31 has moved beyond the throttling ring 39; the oil that is present in the slowing chamber 27, in order to reach the hole 31 , passes through the throttling passage 35, enters the further slowing passage 70, which has a further reduced cross- section, between the throttling ring 39 and the surface of the outer telescopic element 13, and, by means of a second portion of the throttling passage 50, indicated in Figures 6 and 7, reaches the hole 31.

In this step for slowing the stroke of the outer telescopic element 13 with respect to the containment jacket 11, the outward motion of the first intermediate telescopic element 14 with respect to the outer telescopic element 13 begins already. Upon the encounter between the annular abutment portion 22 and the stroke limiting shoulder 18, the speed of the annular abutment portion 22 is far lower than the speed that the same component has in a similar cylinder of the known type.

The throttling ring 39 and the consequent slowing passage 70 obtained thanks to it, allow the cylinder 10 according to the invention to not suffer from the stroke limiting impacts that are typical of known types of telescopic hydraulic cylinder.

What has been described above for the slowing chamber 27 between the containment jacket 11 and the outer telescopic element 13 is repeated likewise for the other slowing chambers between the several telescopic elements.

The cylinder 10 comprises lower guiding rings, for example 53, 54 in the lower part of the outer telescopic element 13, which are pressed against the containment jacket 1 1, and in the lower part of each one of the other telescopic elements 14, 15, 16 pressed against the corresponding externally adjacent telescopic element 13, 14, 15.

The provision of the slowing chambers 27, 28, 29 and 30 and the simultaneous need for the presence of lower guiding rings, for example 53 and 54 in the lower part of the outer telescopic element 13, makes it necessary to provide an additional series of lower holes 55, 56, 57 and 58 at a series of respective annular chambers 59, 60, 61 and 62 for the passage of the oil through the telescopic elements 13, 14, 15 and 16 from the inlet 26 toward the inner chamber 47 (and vice versa), in situations in which one of the two oil inlet holes 45 and 46 is blocked by the transit of one of the guiding rings 53 and 54.

The annular chambers 59, 60, 61 and 62 are defined between the inner surface of the containment jacket 11 and an annular hollow on the outer surface of the outer telescopic element 13 and, likewise, between the inner surface of a telescopic element 13, 14 and 15 and an annular hollow on the outer surface of the internally adjacent telescopic element.

Figures 9 and 10 clearly show the operation of the additional series of lower holes 55, 56, 57 and 58 and of the corresponding annular chambers

59, 60, 61 and 62.

Figure 9 exemplifies the situation in which the outer telescopic element 13 has risen until a first guiding ring 53 blocks the lower oil inflow hole 45; in this situation the oil continues to flow inside the cylinder and toward the inner chamber 47 by means of the upper oil inflow hole 46, the slowing chambers 27, 28, 29 and 30 and the corresponding holes 31, 32, 33, 34 that mutually connect the slowing chambers and the inner chamber 47.

Figure 10 exemplifies the situation in which the outer telescopic element 13 has risen until the first guiding ring 53 blocks the upper oil inflow hole 46; in this situation, the oil continues to flow inside the cylinder, and toward the inner chamber 47, by means of the lower oil inflow hole 45, the first annular chamber 59, which is provided so as to be arranged at the lower oil inflow hole 45 when the upper hole 46 is blocked by the first guiding ring 53, and likewise by means of the subsequent annular chambers

60, 61 and 62 and the respective through holes 55, 56, 57 and 58.

Both during the elongation step of the cylinder 10 (upward motion) and during the retraction step (descent), the distance between the horizontal plane that passes through the center of the holes of a telescopic element and the one that passes through the center of the holes of any one of the other telescopic elements remains always the same, i.e., they always remain in a relative position with the annular chamber of the adjacent inner telescopic element to ensure the passage of the oil both during the rising step, and during the descent step, of the outermost telescopic element.

Obviously, this occurs except for the last portion during the rising step in which the outermost telescopic element is slowing and the directly subsequent telescopic element begins to exit.

In practice it has been found that the invention achieves the intended aim and objects.

In particular, the invention provides a telescopic hydraulic cylinder in which the stroke limiting impact is reduced greatly with respect to telescopic cylinders of the known type and with it the risk of damage to the abutments and the wear of the product even in conditions of high operating speed.

Therefore, the invention has provided a telescopic hydraulic cylinder that is capable of reducing considerably the generation of vibrations and therefore noise during its operation.

Furthermore, the invention provides a telescopic hydraulic cylinder that has a longer life and less need for maintenance than similar cylinders of the known type.

Moreover, the invention provides a telescopic hydraulic cylinder that can be applied also to hydraulic kits for its operation that are provided with components having a higher performance, i.e., capable of actuating the cylinder more rapidly than what would be possible with similar cylinders of the known type.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the components and the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. PD2014A000177 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A telescopic hydraulic cylinder (10), comprising a containment jacket (11) which is closed at one end by an end plate (12), containing at least one telescopic element (13), a stroke limiting shoulder (18) being provided within said containment jacket (11) and being preset to meet a corresponding annular abutment portion (22) defined externally to the adjacent telescopic element (13), said containment jacket (1 1) having an inlet and an outlet (26) for pressurized oil for pushing said at least one concentric telescopic element (13), said telescopic hydraulic cylinder being characterized in that between said containment jacket (11) and said telescopic element (13) there is, between a stroke limiting shoulder (18) and said respective annular abutment portion (22), a corresponding chamber (27) for slowing the stroke of said telescopic element (13), said slowing chamber (27) having at least one hole (31) for the passage of pressurized oil defined on the corresponding telescopic element (13), between said containment jacket (11) and said telescopic element (13), at said stroke limiting shoulder (18), there being a throttling passage (35) for the pressurized oil that is preset to allow the passage of oil from said slowing chamber (27) to the corresponding oil passage hole (31) when said corresponding oil passage hole (31) is displaced with respect to said slowing chamber (27), a ring being provided to throttle the oil passage section (39, 40, 41 , 42), each throttling ring (39, 40, 41, 42) defining a corresponding slowing passage (70).

2. The telescopic hydraulic cylinder according to claim 1, characterized in that it comprises a plurality of concentric telescopic elements (13, 14, 15, 16), of which an outer telescopic element (13), one or more intermediate telescopic elements (14, 15), and an inner telescopic element (16), said inner telescopic element (16) supporting, externally to the containment jacket (11), a pusher head (17), within said containment jacket (11) and each one of said outer (13) and intermediate (14, 15) telescopic elements there being a stroke limiting shoulder (18, 19, 20, 21) preset to meet a corresponding annular abutment portion (22, 23, 24, 25) that is defined externally to the adjacent outer telescopic element (13), intermediate telescopic elements (14, 15) or inner telescopic element (16), between said containment jacket (11) and said outer telescopic element (13) and between the adjacent outer telescopic element (13), intermediate telescopic elements (14, 15) and inner telescopic element (16) there being, between a stroke limiting shoulder (18, 19, 20, 21) and a respective annular abutment portion (22, 23, 24, 25) corresponding chambers (27, 28, 29, 30) for slowing the stroke limit impact of each telescopic element, each slowing chamber (27, 28, 29, 30) being provided with a hole between said containment jacket (11) and said outer telescopic element (13), between the latter and the adjacent intermediate telescopic element (14), between adjacent intermediate telescopic elements (14 and 15) and between the inner telescopic element (16) and the intermediate telescopic element that is adjacent thereto, at each stroke limiting shoulder (18, 19, 20, 21) there being a passage (35, 36, 37, 38) for throttling the pressurized oil, which is preset to allow the passage of oil from said slowing chamber (27, 28, 29, 30) to the corresponding oil passage hole (31, 32, 33, 34) when said corresponding oil passage hole is displaced with respect to the respective slowing chamber.

3. The cylinder according to one or more of the preceding claims, characterized in that said containment jacket (11), the first telescopic element (13) and the intermediate telescopic elements (14, 15) have, proximate to the corresponding stroke limiting shoulder (18, 19, 20, 21) and on the opposite side with respect to the slowing chamber (27, 28, 29, 30), a ring for throttling the oil passage section (39, 40, 41, 42), each throttling ring (39, 40, 41, 42) defining a corresponding slowing passage (70).

4. The cylinder according to one or more of the preceding claims, characterized in that at the inlet (26) there are two through holes (45, 46) for the inflow and outflow of oil that are defined on the containment jacket (11).

5. The cylinder according to one or more of the preceding claims, characterized in that the outer telescopic element (13) has an annular resting element (49) for lifting the adjacent telescopic element (14) and, likewise, the other intermediate telescopic elements (14, 15) have corresponding annular resting elements (50, 51) for lifting the adjacent innermost telescopic elements (15, 16).

6. The cylinder according to one or more of the preceding claims, characterized in that it comprises lower guiding rings (53, 54) in the lower part of the outer telescopic element (13), which are pressed against the containment jacket (11), and in the lower part of each one of the other telescopic elements (14, 15, 16) are pressed against the corresponding externally adjacent telescopic element (13, 14, 15).

7. The cylinder according to one or more of the preceding claims, characterized in that it has an additional series of lower holes (55, 56, 57,

58) at a series of respective annular chambers (59, 60, 61 , 62) for the passage of oil through the telescopic elements (13, 14, 15, 16) from the inlet (26) toward the inner chamber (47) and vice versa, in the situations in which one of the two oil inflow holes (45, 46) is blocked by the transit of one of the guiding rings (53, 54).

8. The cylinder according to one or more of the preceding claims, characterized in that said annular chambers (59, 60, 61, 62) are defined between the inner surface of the containment jacket (11) and an annular hollow on the outer surface of the outer telescopic element (13) and likewise between the inner surface of a telescopic element (13, 14, 15) and an annular hollow on the outer surface of the internally adjacent telescopic element.