FR2513370A1 - HYDRAULIC MECHANISM WITH PUSH PISTON, PARTICULARLY FOR USE AS A RIPAGE AND ADVANCING CYLINDER IN UNDERGROUND OPERATIONS, INCLUDING PERMANENT MAGNETS MOUNTED IN THE PISTON ROD - Google Patents

Abstract

THE INVENTION CONCERNS AN ARRANGEMENT OF PERMANENT MAGNETS SERVING SIGNAL OR SIMILAR EMITTERS, MOUNTED IN THE PISTON ROD 22 OF A PUSH PISTON HYDRAULIC MECHANISM, INTENDED IN PARTICULAR FOR RIPING OR ADVANCING JACKS. UNDERGROUND EXPLOITATIONS. ACCORDING TO THE INVENTION, AT LEAST TWO ROWS OF MAGNETS ARE ARRANGED IN THE PISTON ROD 22, THE PERMANENT MAGNETS OF ONE OF THE ROWS BEING OFFSET WITH THOSE OF THE OTHER OR THE OTHER ROWS, TOWARDS THE ROWS. PISTON ROD AXLE. THIS ARRANGEMENT OF THE MAGNETS ALLOWS THE DISTANCE TAKEN BY THE CYLINDER TO BE MEASURED WITHOUT ANY ERRORMAL MEASUREMENT DUE TO BREATHING OR BACKWARD MOVEMENTS IN THE REVERSE DIRECTION TO THAT OF THE MEASUREMENT.

Description

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  Hydraulic push piston mechanism, in particular for use as a shifting and advancing cylinder in underground operations, comprising magnets

  permanent mounted in the piston rod.

  The invention relates to a hydraulic push piston mechanism, intended in particular to be used as a conveyor shift and support advancement cylinder.

  underground operations, including permanent magnets

  nents mounted in the piston rod which cooperate as signal transmitters with a feeler member or a member

  switching or the like that can be influenced magnetic-

  preferably mounted on the cylinder.

  Document DE-OS 29 17 609 discloses hydraulic push-piston mechanisms inside the rod of which permanent magnets are introduced. The permanent magnets serve as signal generators or control devices and they emit signals. electric on

  of the race or they actuate magnetic switches

  as a function of the stroke The thrust pistons fitted with permanent magnets are preferably used for controlling hydraulic or electro-hydraulic supports of underground mining operations, and they are used for example to carry out a simultaneous or sequential control of cylinders of work, such as conveyor shift and support advance cylinders,

hat and the like.

  When using push piston mechanisms as shift cylinders for underground conveying and felling installations, permanent magnets which are mounted in the piston rod can also be used to measure the distance traveled, and thereby also to measure the progress of felling A row of magnets is then placed in the piston rod, the magnets of which, during the stroke of the shifting cylinder, pass one after the other in front of the mounted feeler or switching member at the end of the cylinder of the jack, and emitting electrical pulses which are counted by an electronic pulse counter which provides an indication of the distance traveled. An accurate distance measurement can only be made when reliable transmission of signals is assured on the one hand, even when the distance between the permanent magnets in the piston rod is relatively short and when there is on the other hand that the counting of the pulses is only carried out in the predetermined direction of travel, and when it is a shifting cylinders, in the direction of shifting and not in the opposite direction of the travel of the mechanism to

  thrust piston There are uncontrolled movements

  bles of this type, in the opposite direction of travel, with shifting cylinders for conveying and -felling installations and the like, for example when it is called so-called breathing movements, that is to say when the conveyor is pushed back towards the embankment by a slaughter machine passing in front of it, such as a plane, in order to form a passage for the slaughter machine During these breathing movements and return movements which after the planer has passed, it is possible that a permanent magnet mounted in

  the piston rod passes several times in front of the pal-

  fear, which causes the emission of several impulses which

distort the distance measurement.

  When it comes to push piston mechanisms used

  For other purposes, there may also be wanted or unwanted return runs that distort the results of the measurement when you only want to measure the distance in

a sense of race.

  The object of the invention is therefore to mount the permanent magnets in the piston rod of a thrust piston mechanism, in particular of a shifting cylinder, so as to be able to obtain a reliable measurement of the distance by eliminating the disturbing influences mentioned, which arise in particular from breathing movements and return strokes, using electronic counting devices

  simple constitution, or other counting mechanisms.

  According to the invention, this problem is solved by the fact that at least two rows of magnets offset relative to each other in the peripheral direction are mounted in the piston rod, the permanent magnets in one of the rows, possibly at with the exception of permanent magnets located in the end zone of the piston rod, being offset with respect to those of the other or of the other rows of magnets in the direction of the axis of the piston rod It is advantageous that the the arrangement is made in such a way that the rows of magnets comprise, in the terminal region of the piston rod, permanent magnets arranged in the same axial position and one next to the other in the peripheral direction of the piston rod, which provide a indication of the end position or cause the counting device to be connected at the start of the working stroke and towards the distance to be measured When there are two rows of magnets, the permanent magnets of one of the ra nées are arranged, seen in axial direction of the piston rod, in the middle between the permanent magnets of the other row Inside the two rows of magnets, these magnets are separated from each other by equal distances, the permanent magnets in one row being offset from those in the other row by half the distance separating the magnets inside the two rows Advantageously, there are available for each row of magnets and at the end of the cylinder of the actuator a particular feeler or switching member, or the like,

  for example an induction coil or a magnet switch

  than. Thanks to the arrangement according to the invention of permanent magnets in at least two rows, the magnets of a row being respectively arranged in the free spaces

  left between the magnets in the other row, we have the possibility

  lity of placing the magnets at a greater distance from each other and thereby eliminating contrary magnetic influences In particular, it is then possible to avoid erroneous measurements originating from so-called breathing movements or back strokes. this

  result using simple electronic blocking circuits

  pulse cage or pulse interlock devices

  any sions, which are formed so that the pulses are counted and used for distance measurement only when the pulses are sent by the magnets of the row of magnets in the direction of the stroke to be measured and in an alternating sequence If by against several pulses are sent one after the other by the same magnet from one or the other of the rows of magnets,

  as is the case for example when there are movements

  conveyor breaths, these erroneous impulses

  are suppressed due to electrical or electro- locking

  so that they are not registered as

that counting pulses.

  When there are in particular two rows of magnets, an advantageous arrangement can be obtained by placing the magnets inside each row so that their blades are in the same direction, possibly except for the permanent magnets used to the indication of the terminal position In this case, the permanent magnets of a row of magnets can have their pale south disposed on the surface of the piston, while the permanent magnets of the neighboring row have their north pole disposed on the surface of the piston rod This arrangement supposes that the magnets of one of the rows are inserted in the piston rod so that their poles are reversed compared to those of the other row, because an incorrect arrangement of the poles would lead to

measurement errors.

  In general, it is more advantageous for the permanent magnets of all the rows to be inserted in the piston rod so that their poles are all in the same

  sense, all pale north or - all south poles being available -

  on the surface of the piston rod In this case also

  ment, each row of magnets can be associated with a feeler or switching member, or the like, and an electrical lock can be provided so that the counting pulse originating respectively from a row of magnets is blocked until that a counting pulse of the other row of magnets is triggered When two magnets intended for indicating the end position are placed on both

  ends of the piston rod, we have the possibility -

  count up and down, which allows you to measure a distance using a

  shift and advancement cylinder, also during advancement

support cement.

  Finally, the invention also offers a possibility of solution according to which there is only provided in the piston rod of the pushing piston mechanism a single row of permanent magnets whose poles are reversed.

  also case, two feelers or commu-

  tation, or the like, for detecting permanent magnets, one of which is sensitive only to pulses from magnets with the south pole at the surface and the other only to pulses from magnets with the north pole at the surface Again, pulse lock can be used to ensure that the pulses can only be saved as counting pulses.

  when they are unleaved alternately pulses from

  of magnets whose north pole is on the surface and pulses from magnets whose south pole is on the surface Thanks to this arrangement, the distances between magnets can be relatively reduced when the goal is to measure small distances, as for example the

  case for planed installations.

  The invention will now be explained in more detail using the embodiments shown in the accompanying drawings in which: FIGS. 1 to 3 respectively represent various arrangements of the magnets mounted in the piston rod of a

  shifting cylinder of a supporting bridge walking mechanism

  schematically shown in plan, Figures la to 3a are diagrams showing the arrangement of the magnets in the shift cylinders of the figures

1 to 3,

  Figure 4 is a cross-sectional view of a piston rod showing the arrangement of a permanent magnet in

  the bore in the piston rod.

  Figures 1 to 3 show a conveyor 10 forming part of an underground slaughtering and conveying installation, for example a planed installation, and constituted in the traditional way by a raclette chain conveyor which can be slipped by means of a hydraulic shift cylinder 11 in the direction of arrow A, that is to say in the direction of the working face The shift cylinders 11 are supported on hydraulic supports such as support shields 12 FIGS. 1 to 3 represent only the part of the base frame of a single support device 12 comprising the divided base frames 13 On the parts of the frame of the base U support hydraulic props 14 mounted in

  foot joints, and supporting a hat.

  The individual hydraulic support devices are connected via their shift mechanism

  to the conveyor 10 located in front of the cutting face The mechanics

  shifting meshes are constituted by a guide linkage formed for example by two elastic guide rods 15, and the shifting cylinder 11 interposed between them The guide rods 15 are connected at their front end to a head of

  rods 16 and are connected to the conveyor 10 by an articulation

  tion 17 and by means of the head of rods 16 At their ends

  rear tees, the guide rods 15 are connected by a cross member 18 which is guided in guide rails 20 of the parts 13 of the base frame by means of guide elements 19 The shift cylinder 11 is connected to the cross member 18 by a connection articulation 21 The rod 22 of the shifting cylinder 11 is connected to a transverse yoke 23 which connects

  the two parts 13 of the base frame, in its front part.

  These walking mechanisms with interposed shifting cylinders are known. To slip the conveyor 10 towards the waist (arrow A), the shifting cylinders 11 are sent the hydraulic pressure fluid so as to cause them to enter, which means that the conveyor 10 is advanced by the cylinders which

  retract, via guide rods 15.

  The shifting cylinder 11 then takes support by its piston rod 22 on the support 12 which remains stationary To drive the support device thereafter, the pressure fluid is sent to the shifting cylinder 11 so that it performs a stroke outlet, which causes the rod 22 to come out and

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  advance the support device in the direction of arrow A. In the walking mechanism shown, the shifting cylinders ll therefore simultaneously fulfill the function of advancement cylinders with the help of which the advancement takes place

walking support.

  As shown in Figure 1 in conjunction with the schematic view

  tick of FIG. 1a, permanent magnets are mounted in the piston rod 22 of the shifting cylinder 11, in two rows I and II In a row I, the permanent magnets have their south pole S at the level of the surface of the rod piston, while in the second row II, the permanent magnets have their pole reversed, their pale north N being

  then at the level of the piston rod surface The distance

  this "X" which separates the magnets inside the two rows I and It is the same The magnets in row I are offset from those of row II by the distance "X / 2", in

  the direction of the piston rod axis In the periphery direction

  as the rod 22 of the piston, the magnets of the two rows I and II are advantageously offset with respect to each other by at least 90, and preferably by 1800 In the latter case, the magnets are therefore arranged on the diametrically sides opposite of the piston rod 22 of round shape. In the guide sleeve 24 disposed at the end of the cylinder of the shifting cylinder l are mounted feeler members

  or switching 25 and 26 in alignment with the two ran-

  of magnets I and II, in front of which pass the permanent magnets of the two rows I and II when the piston rod is retracted 22 The feeler or switching members are constituted, for example, by induction coils or magnetic switches , or the like, which send electrical pulses when the permanent magnets pass in front of them, these pulses being sent to an electronic counting device 29 by connection lines 27

and 28.

  In the end of the rod 22 which is located on the side of the piston are inserted two permanent magnets 30 and 31 serving to indicate the end position The magnet 30 is located in the row of magnets I and the magnet 31 in the row of magnets II, the N and S poles of the two magnets 30 and 31 being inverted with respect to the poles of the other magnets in the rows of magnets I and II When the piston rod is completely extended, the two magnets 30 and 31 respectively cause the emission of a signal applied to the feeler or switching members or 26 This signal then enables the electronic counting device 29, that is to say the branch for counting, so that the measurement of the distance is performed during the shifting of the conveyor 10 which follows, in the direction of the arrow A. During the shifting, the cylinder of the jack in which the feeler or switching members 25 and 26 are mounted moves in front of the magnets of the two rows of magnets I and II, a magnet presenting the north pole and a magnet having the south pole then being alternately swept by the feeler or switching members 25 and 26 The electrical pulses sent by the feeler or switching members are counted by the counting device 29 and used by addition to measure the distance traveled by the cylinder

  shifting, or the advance of the support.

  It will be assumed that during the shifting process the feeler or switching member 25 has reached position P in FIG. 1a and that it then passes in front of the permanent magnet 32

  placed immediately in front of this position P and presented

  both its south pole, and has therefore sent a counting pulse to the counting device 29 If in this position the cylinder of the shifting cylinder is brought back in the opposite direction to the arrow A, with output of its piston rod , which can happen when the conveyor 10 is slightly turned back by the coal planer which circulates in front of it, the feeler or switching member 25 again passes in front of the permanent magnet 32, which causes the sending of another pulse which would cause an erroneous measurement if it were considered as a counting pulse To avoid such erroneous measurements, the counting device 29 is equipped with a blocking or locking circuit which is constituted so that only the pulses of counting are

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  counted to measure the distance when an impulse coming from a magnet N and a impulse coming from a magnet S of the two rows of magnets are sent alternately The electronic counting device is then constituted so that after each counting of a pulse N, the following counting pulse X is blocked until a pulse S is then sent.

  reliable distance measurement, regardless of any movement

  Breathing elements of the conveyor 10 Simultaneously, and thanks to the arrangement of the permanent magnets in two rows I and II offset in the peripheral direction of the piston rod 22, it is possible to double the distance separating the magnets inside a row, that is to say the distance "X", with respect to single row arrangements If the magnets are located in the two rows I and II in

  being separated for example by a distance of 100 mm, a movement

  breathing with a maximum of about 40 to 45 mm is

  then possible without causing erroneous measurements.

  The embodiment of Figures 2 and 2a differ

  cie of that of Figures 1 and the fact that the poles of the two rows of magnets I and II are oriented in the same direction, and have for example their pale north N Permanent magnets 30 and 31 which are arranged at the end of the

  piston rod, and which serve to indicate the end position

  nale and to trigger the counting device 29, are also in this case inserted into the piston rod so as to present their north pole N on the surface According to

  this arrangement, we get the same effect when the impul-

  counting sion coming respectively from a row of

  mants I or II is blocked until a counting pulse is triggered respectively by the other row of magnets II or I In this case also, we work by using a locking mechanism to be sure that only the pulses which are delivered sequentially by the permanent magnets of one or the other row of magnets and via the feeler or switching members 25, 26 are counted and used for the measurement of the distance Si for example, l feeler or switching member 25 is in position P, the pulse delivered during the return stroke by the permanent magnet 32 which had been previously exceeded, is not counted because in this position only a pulse from '' a magnet located in the other row

It can be counted.

  It will be understood that, according to the arrangement of the magnets in FIGS. 2 and 2 a, the permanent magnets of the two rows I and II can be arranged so as to present their south pole.

  There is also the possibility of planning on the outside.

  external mite of the piston rod two permanent magnets 30, 31 mounted side by side, which simultaneously supply signals when the shifting cylinder is fully retracted, these signals triggering an indication of end of travel With this arrangement, it would also be possible to count forwards (retraction stroke of the shift cylinder) or backward (return stroke of the shift cylinder or advancement

  of the support), the two pairs of position magnets

  nale 30, 31 determining the activation or connection of the metering device 29 in each of the two positions

end of the race.

  Figures 3 and 3a show a mounting of the magnets in the piston rod 22 in a single row The permanent magnets are arranged on the piston rod 22 so

  that their poles are reversed, ie N-S-N-S-etc At the extreme

  half of the rod which is located on the side of the piston are available

  two permanent magnets 30 and 31, in the longitudinal direction

  nale of the piston rod and immediately one behind

  the other, to indicate the end of the race

  corresponding, the feeler or switching members 25 and 26 are arranged in the direction of the axis of the piston rod directly one behind the other, so that they are located in the area of action of the magnets 30 and 31 when the shifting cylinder is fully extended To exclude in this

  also erroneous measurements caused by movements

  breathing devices or the like, the counting device 29 must be fitted with a locking device so

  pulses are only counted when these pulses are

  are delivered sequentially from an N magnet,

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  of a magnet S, of a magnet N, etc. The feeler or switching member 25 is then influenced only by the permanent magnets located in position N and the feeler or switching member 26 only by the permanent magnets being in position S. The arrangement of the magnets which has been described above and whose poles are reversed on the piston rod 22 allows only relatively short breathing paths

  and requires greater distances between the permanent magnets

  nents on the piston rod, which means that the number of a-

  mants to be mounted on the length of the piston rod is

greatly decreased.

  Figure 4 shows how the permanent magnets

  are placed in the piston rod 22 The permanent magnet

  bar-shaped and indicated at 37 is mounted in the desired polar orientation in a pot-shaped bush 38, with a slight axial clearance, the bush being arranged in a radial bore 39 of the piston rod 22 by tight adjustment and pressing by its open side against the bottom 40 of the bore The bottom 41 of the sleeve 38 is connected to the circular periphery 42 of the piston rod and therefore has a rounded and corresponding circular shape The thickness of the bottom 41 of the socket is weaker than that of the wall

  cylindrical of the sleeve It is for example from 1 to 2 mm.

  The sleeve 38 is made of a stainless steel anti-magnetic

devil and resistant to acids.

  The arrangements of the magnets which are described above with reference to FIGS. 1 to 3 can naturally be provided when the shifting cylinder 11 is fixed to the conveyor 10 by its piston rod 22 and to the support device by its cylinder. In this case, the piston rod 22 leaves the cylinder in the direction A when there is shifting of the conveyor. As a result, the permanent magnets 30 and 31 serving to

  indicate the terminal position can be mounted close-

  tee of the free end of the piston rod.

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Claims (8)

  1 Hydraulic mechanism with push piston, intended in particular to be used as a jack for shifting a conveyor and advancing support for underground operations, comprising permanent magnets mounted in the piston rod which cooperate as transmitters of signals with a feeler, switching element or the like capable of being influenced magnetically and preferably mounted on the actuator, characterized in that at least two rows of magnets (I, II) are mounted in the piston rod ( 22), the permanent magnets of one of the rows, possibly with the exception of the permanent magnets (30, 31) located in the end region of the piston rod, being offset with respect to those of the other or the others rows   magnets towards the axis of the piston rod.   2 push piston mechanism according to claim   1, characterized in that the rows of magnets (I, II) include   take in the end zone of the piston rod (22), permanent magnets (30, 31) in the same axial position of the piston rod intended to indicate the termi-_ position   or connect the counting device (29).   3 push piston mechanism according to claim 1 or 2, characterized in that, when there are two rows of magnets (I, II), the permanent magnets of one of the rows (I), viewed in direction axial of the piston rod (22), are located in the middle between the permanent magnets on the other row of magnets (II).   4 Push piston mechanism according to one of the claims   cations 1 to 3, characterized in that at the end of the jack * is mounted, for each row of magnets (I, II), a specific feeler or switching member (25, 26), for example   an induction coil or a magnetic switch or the like.   Push piston mechanism according to one of the claims   cations 1 to 4, characterized in that possibly except   tion of permanent magnets (30, 31) used for indication   from the end position, the permanent magnets are available   placed inside each row of magnets- (I, II) of '337 C   so as to present the same pole.   6 Push piston mechanism according to one of the resents   dications 1 to 5, characterized in that the permanent magnets   of one of the rows of magnets (I) are arranged on the   face of the piston rod so as to present their pale south (S), and the permanent magnets of the neighboring row (II)   so as to present their pale north (N).   7 Push piston mechanism according to one of the resents   dications 1 to 6, characterized in that when there are two rows of magnets (I, II), there is provided in one of the rows of magnets (I) having their south pole a permanent magnet (30) constituting a terminal position indicating magnet and having its pale north, while in the other row of magnets (II) where the permanent magnets have their pale north, there is provided a permanent magnet (31) constituting a position indicating magnet terminal with its south pole.   8 Push piston mechanism according to one of the res-   dications 1 to 5, characterized in that the permanent magnets   of all the rows (I, II) are oriented so as to pre- feel their same pole.   9 Push piston mechanism according to one of the resents   dications 1 to 8, characterized in that at both ends of   the piston rod (22), two permanent magnets (30, 31) used   the terminal position indicators are arranged side by side and in two rows of magnets, the pairs of magnets (30, 31) being preferably arranged so as to present the same pale.   Hydraulic push piston mechanism according to the preamble of claim 1, intended in particular to be   used as a conveyor shift and advance cylinder   support for underground operations, including   permanent magnets mounted in the piston rod which coo-   operate as signal emitters with a feeler, switching or like organ capable of being influenced   magnetically and preferably mounted on the cylinder, characteristic   se in that the permanent magnets are arranged with their blades alternately reversed in a single row of magnets (I) in the piston rod (22), and in that to explore 1337 C   permanent magnets, two feelers or switches (25, 26) or the like are provided, which are arranged in   longitudinal direction of the piston rod (22), direct-   one behind the other in the row of magnets (I) 11 Push piston mechanism according to any one   as claims 1 to 10, characterized in that the   permanent magnets are mounted in sockets in the form of pots (38) made of stainless steel and resistant to acids, which are arranged in bores (39) of the piston rod (22) by tight fitting and whose bottom surfaces (41 ) are precisely connected to the surface of the piston rod, and rounded to match that of the surface of the piston rod.