Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/20—Other details, e.g. assembly with regulating devices
  • F15B15/24—Other details, e.g. assembly with regulating devices for restricting the stroke
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/08—Characterised by the construction of the motor unit
  • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
  • F15B15/16—Characterised by the construction of the motor unit of the straight-cylinder type of the telescopic type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/20—Other details, e.g. assembly with regulating devices
  • F15B15/26—Locking mechanisms
  • F15B15/261—Locking mechanisms using positive interengagement, e.g. balls and grooves, for locking in the end positions

Definitions

• the present invention relates generally to cylinders, and more particularly to telescopic single-acting cylinders.
• cylinders of the type under consideration comprise a cylinder, with a connection to a source of pressurized fluid, and inside this cylinder a series of coaxial tabular elements, which can occupy an advanced position for which they extend the said cylinder, or a retracted position inside the cylinder in question.
• the above bular elements com ⁇ carry front and rear end-of-travel means so that, under the effect of the pressure of the fluid, the tubular element having the largest reaction surface causes on its course the other elements, then it is the turn of an adjacent element and so on, until said tubular elements occupy an advanced position for which they extend said cylinder. From such an advanced position, the process is exerted inversely towards the retracted position for which the said elements are housed inside the cylinder.
• the aforementioned front and rear end-of-travel means are generally formed by heels fitted at the ends of the tubular elements; between these heels is thus formed an annular pressure in which a heel of a neighboring element can move, itself being able to comprise an annular groove with two end heels for the movement of another tubular element and thus following, the length of the abovementioned annular depressions defining the stroke of the tubular element, slidably mounted in the depressions.
• the elements in question are obtained from conventional tubes, machined over their entire length both outside and inside to form the depressions and, therefore, the heels.
• the size of the telescopic jacks equipped with such tubular elements is important in particular because the depressions formed on the tubular elements - for the deflection of the heel create a large space between said elements.
• the object of the present invention is to solve the problem posed concerning the weight and the bulk, while retaining and even substantially improving the mechanical resistance of the jack, with means having practically no influence on the re price comes.
• the invention provides front and rear end-of-travel means capable of allowing the progressive development of the exterior of the cylinder, or the progressive withdrawal of the interior of this cylinder from said elements, the said means of front limit switch being characterized in that they advantageously consist of at least one interrupted and elastically deformable ring which is, in a retracted position of the tubular elements, log
• the end means of front stroke is resting, in part, in the aforementioned depression and in part in a second depression provided for this purpose in said second tubular element.
• the rear end-of-travel means they are advantageously, according to another characteristic of the invention, constituted by a rod engaged in a groove formed towards the rear end and on the inner surface of a tubular element , by having a protruding part thus constituting a stop for another tubular element in contact with the internal surface of the tooth.
• the cylinders according to the invention are less bulky in that there is no lost space between the tubular elements, these being mounted to slide one on the other without significant play, namely just the play necessary for operation; they are lighter, due to the fact that the thickness of the tubes is less than in the past, and at the same time offer mechanical characteristics superior to traditional telescopic jacks.
• the machining operations are reduced to a strict minimum, namely, light sanding and machining of the depressions necessary for the front and rear abutment means, and for the various seals. All these construction features taken together lead to an actuator in which the disadvantages mentioned above are eliminated.
• FIG. 1 illustrates in axial section an embodiment of a telescopic jack according to the invention, the tubular elements the constituent being positio retracted;
• FIG. 1 illustrates in axial section an embodiment of a telescopic jack according to the invention, the tubular elements the constituent being positio retracted;
• FIG. 2 is a partial view, on a larger scale, showing an embodiment of the front limit switch means disposed between two neighboring tabular elements;
• Figure 3 is a view that a front limit switch means is in the active position;
• Figure 4 is a view showing the actuator according to Figure 1 5 with its tubular elements running end position before;
• Figures 5 to 8 show, partially schematically, the operation of the front end of course means when a tubular member is moved from an advanced position to a retracted position;
• Figures 9 and 10 show an alternative embodiment of the front end-of-travel means.
• a cylinder of the kind with teescopic elements 5 comprises a cylinder 10 and a certain number of tubular elements, for example three, respectively.
• the cylinder 10, as well as the telescopic elements are obtained from 0 drawn steel tubes to which only surface treatment such as polishing is applied.
• the cylinder 10 itself consists of two tubular sections 10A, 10B, assembled by welding 10C, while a bottom 10D attached by welding 10E on the free end of the tubular section 10B, seals the cylinder at one end. back.
• the tubular section 10B also carries two diametrically opposed bolts 16, 17 intended to allow
• the section 10A of the cylinder 10 has an inner diameter D smaller than the inside diameter Dl of the section 10B so that an annular recess 10F is thus formed between the interior surface of the section 10B and the tubular element 11.
• the aforementioned recess is limited, on the one hand, by a circular shoulder 10G formed by the difference in diameters D, Dl and, on the other hand, by the front face 11B of an annular part 11A attached by welding to the end rear of the tubular element 11, the annular part being movable in the recess 10F; the aforementioned shoulder 10G as well as the bottom 10D thus form end-of-travel stops respectively front and rear of the first tubular element 11.
• the annular part 11A comprises channels 11C, 11D allowing the admission of pressurized fluid to the reaction surfaces of elements 11, 12 and 13 respectively.
• the section 10A of the cylinder 10 comprises an annular housing 10H in which is placed a flat ring 20 for example of plastic material having a guiding role for the second tubular element 11.
• the section 10A of the cylinder 10 internally comprises first of all an annular housing 101 for a ring 21 similar to the aforementioned ring 20, then a housing 10J for a seal 23 and finally a clearance 24 for another lip seal 25.
• the first tubular element 11 is coaxial with the cylinder section 10A, a slight clearance, just necessary for operation, is formed between the cylinder and the first tubular element, which . can thus move axially- between the aforementioned end stops 10G and
• the distance between a front face 11B of the annular part 11A and the shoulder 10G forming a front stop determines the length L of the stroke of the tabular element 11.
• end-of-travel stops both in the retracted position thereof (rear end-of-travel stop) and in the advanced position (front end-of-travel stops).
• the rear end of travel stop of the tubular element 11 is constituted by an annular groove 11E formed on the inner face of the tubular element 11 in which is engaged a rod 30 intended to cooperate with a circular imprint 12A formed at the rear end of the tubular element 12.
• the aforementioned rod 30 has a protruding part thus constituting a rear end-of-travel stop at the tubular element 12, while a front end-of-travel stop at this tabular element 12 is formed by a device which will now be described with more particular reference to FIGS. 2 and 3.
• the tubular element 11 comprises, on its inner wall, a first circular depression generally indicated at 40 having in cross section a generally oblique shape, comprising a notch in a quarter of a circle 41 extended rearward by a substantially flat section, forming a ramp 42; as for the tubular element 12 spaced from the previous one by a slight play as has been said before, it comprises on its external surface a second so-called depression with stages indicated generally in
• the tubular element 11 When the tubular elements 11, 12 and 13 are in the rear end-of-travel position, as shown in FIG. 1, the tubular element 11 is in abutment on the bottom 10D, while the tubular elements 12, 13 are in abutment by their respective rear ends on the rods 30; simultaneously, the front end-of-travel devices are inoperative because the rods 50 are compressed by the elements 11 and 12 and are housed in the groove 44 of the second depression 43.
• the tabular element 13 which, in the example shown, has at its front end a connecting fitting 60 with a passage 60A for fixing to any member, for example a vehicle skip or other, pivotally mounted while at its rear end, it is closed by a bottom 61, attached by welding 63 on a tubular section 13A.
• the tubular element 13 is moved towards the rear only, retracting at the start of its movement towards the rear, the ring 50 as it is clearly visible at
• tubular element 12 which is driven from its front end position to its retracted rear end position, in a manner similar to what has just been described for the tubular element 13.
• tubular element 11 apart from the fact that its rear end-of-travel position is determined by the annular part 11A coming into contact with the bottom 10D.
• tubular elements are perfectly guided by the presence of the guide rings 20, and also by the fact that there is a very slight play between elements.
• FIGS. 9 and 10 showing a variant embodiment of the front end-of-travel device, this variant having in particular the aim of allowing the admission of higher pressures, and, consequently, of increasing the capacities of loads of telescopic cylinders thus equipped.
• an elastic ring 50 as a means of end of travel before a tubular element, has mechanical resistance characteristics depending on its dimensions. As it is not possible to reduce the resistance of the tubular elements and providing deeper grooves for more substantial race rings, the invention provides to equip the tubular elements with two means of end of course before.
• FIGS. 9 and 10 above two tabular elements have been shown partially such as, for example, the tubular elements 11 and 12 previously described, and it can be seen that the tubular element 11 has on its inner surface, a pair of depressions each indicated generally by 60 and 61, the generally oblique depression 60 having a section similar to the depression -4 previously described, while the multi-stage depression 6 has a section similar to the depression 43, described further, the deepest stage 62 being located towards the rear and extended towards the front by a second stage 6, the depth of which is substantially half of the stage 62.
• the depressions 60, 61 are spaced apart by a pitch PI.
• the tubular element 12 has on s external surface a pair of depressions indicated generally at 65, 66, the depression 65 located towards the rear comprising two stages 67, 68 similar to the depressurization 43 of FIG. 2, and the depression 66 situated towards the front comprising a groove substantially in a quadrant of circle 69 followed, towards the front, by a ramp 70, almost pe, planar, opening onto the external surface of the element 12.
• the step P2 of depressions 65, 66 is analogous to not PI of depressions 60, 61.
• the depression 65 houses an interrupted and elastically deformable ring 71 which is compressed when the elements 11 e 12 are in the rear end-of-travel position, while the depression 61 and more precisely the stage 62 houses a ring 72 which is expanded when the said elements are in the position indicated above.
• the ring 71 therefore tends to deploy radially along the arrow -F4 while the ring 72 tends to close on itself radially along the arrow F5.
• the front end-of-travel rings that is to say the rings 50, 71, 72 have a circular section, but it is understood that these rings could have a different section, for example quadrangular, or oval, with of course,
• tubular elements 11, 12, 13 have decreasing health thicknesses, as is clearly visible in the drawings, the same is true of the rings 50, 71, 72 which themselves, decreasing sections as the diameter of the tubular elements decreases.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Actuator (AREA)
• Quick-Acting Or Multi-Walled Pipe Joints (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9242738

Family Applications (1)

Country Status (5)

Families Citing this family (21)

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• 1980
  • 1980-06-05 FR FR8012494A patent/FR2484031A1/fr active Granted
• 1981
  • 1981-06-04 WO PCT/FR1981/000070 patent/WO1981003528A1/fr not_active Ceased
  • 1981-06-04 EP EP81901519A patent/EP0053144A1/fr not_active Ceased
  • 1981-06-04 JP JP56501760A patent/JPS57501137A/ja active Pending
  • 1981-06-04 US US06/348,047 patent/US4471944A/en not_active Expired - Fee Related

Non-Patent Citations (1)

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