US 3866882 A
A device for continuously pulling an elongated member, such as a pipe or cable, comprising pairs of opposite driving elements provided with endless chains carrying gripping pads. Each element is removably housed in a recess provided in a frame having an axial passageway for the elongated member.
Description (OCR text may contain errors)
United States Patent Willm et al.
[ Feb. 18, 1975 DEVICE FOR CONTINUOUSLY PULLING AN ELONGATED MEMBER Inventors: Yves Willm, Suresnes; Jean Thiery,
Le Pecq; Michel Chatard, Chatou; Pierre Grolet, Orgerus, all of France Institut Francais du Petrole, des Carburants et Lubrifiants, Rueil-Malmaison, France Filed: May 22, 1973 Appl. No.: 362,739
Foreign Application Priority Data May 30, 1972 France..., 72.19408 US. Cl. .7 254/29 R, 226/172 Int. Cl E2lb 19/00 Field of Search 226/172, 173; 254/29 R  References Cited UNITED STATES PATENTS 2,251,291 8/1941 Reichelt 254/29 R 3,024,956 3/1962 Gretter 226/172 3,620,432 11/1971 Emery 226/172 3,680,342 8/1972 Mott et a1. 226/172 Primary ExaminerAl Lawrence Smith Assistant Examiner-Robert C. Watson Attorney, Agent, or Firm-Craig & Antonelli  ABSTRACT A device for continuously pulling an elongated member, such as a pipe or cable, comprising pairs of opposite driving elements provided with endless chains carrying gripping pads. Each element is removably housed in a recess provided in a frame having an axial passageway for the elongated member,
4 Claims, 4 Drawing Figures PATENTEB FEB I 8 I975 sum 10F 4 FIG] FIG. it
PATEHTED FEB] 81975 SHEET 2 UF 6.
PATENTED FEB 1 8 I975 sum 3 or 4 PATENTEU FEB I 8 I975 saw u or 4 DEVICE FOR CONTINUOUSLY PULLING AN ELONGATED MEMBER The invention relates to a new device for continuously pulling an elongated member, such as a pipe, a flexible line, a cable or the like, which device is of the type including at least two endless pulling means having endless chains located on both sides of the elongated member which carry gripping pads and can be brought close to each other so as to grip or clamp the elongated member.
In the following, specification reference will be made more particularly by way of non limitative example, only to devices used for pulling drill pipes, of the type comprising at least two endless chains carrying gripping pads.
Handling a drill pipe requires the application of high tractive forces (several tens of tons) whose value is, in particular, a function of the weight of the drill pipe.
As a result the endless chain pulling means must be of large size and consequently are difficult to move from one location to another.
Moreover every mechanical failure of an endless chain pulling means makes it necessary to completely interrupt the drill pipe handling operations, until the failure has been fully repaired.
Another drawback of the endless chain means now in use lies in the fact that at the inlet of the endless chain means, the drill pipe is subjected to a maximum tension, while at the outlet, this tension is substantially equal to zero; this fact, due to the longitudinal elasticity of the drill pipe, generally results in a deterioration of this drill pipe by the gripping pads or, conversely, in a deterioration of the pads by the pipe.
An object of the present invention is accordingly to provide a device for continuously pulling an elongated member of the above-mentioned type, which avoids or at least reduces the drawbacks of the prior devices.
- This object is attained, according to the invention by means of .a device for continuously pulling an elongated member, comprising at least one pair of pulling means symmetrically located with respect to the axis of the elongated member, each of said pulling means including one endless chain carrying pads for gripping the elongated member, said endless chain passing successively on a sprocket wheel driven in rotation by driving means and on a return sprocket wheel, said endless chain having, at least, one substantially rectilinear portion in close proximity to the elongated member, the gripping pads engaging the elongated member along said substantially rectilinear portion, each of said pulling means being removably mounted in a housing provided in a frame having an axial passageway for the elongated member, means for displacing each of said pulling means between a first position in which said pulling means grips the elongated member and a second position in which said pulling means is spaced from the elongated member and can be removed from its housing by sliding along guide means.
The invention will be better understood and other advantages thereof will become apparent from the following description of a particular, but non limitative, embodiment thereof, illustrated by the accompanying drawings wherein:
FIG. 1 diagrammatically shows, in cross section by a vertical plane, adevice according to the invention for pulling an elongated member;
FIG. la diagrammatically shows the means for controlling the position of the pulling bands 7 with respect to the axis of the elongated member.
FIG. 2 diagrammatically illustrates a preferred embodiment of the invention for pulling a flexible drill pipe;
FIG. 3 shows a device equipping the pulling means for compensating the local variations in the external diameter of the elongated member, without any reduction in the gripping forces.
FIG. 1 illustrates a device according to the invention for continuously pulling an elongated member such as a drill pipe.
In this figure the device is diagrammatically illustrated in cross section by a vertical plane passing through the longitudinal axis of the drill pipe.
The drill pipe is, for example, constituted by a flexible pipe 1 which passes through the central opening 2 of a frame 3.
The frame 3 carries four pulling means formed by elements arranged two by two on opposite sides of the drill pipe 1.
In FIG. 1, only the pulling elements located in the plane of the cross section, and designated by the general reference 7, are illustrated, the two other elements being located in a plane perpendicular to that of the drawing.
Each element 7 is formed by a driving sprocket wheel 4 and by a return sprocket wheel 5 on which passes an endless chain 6 having in close vicinity to the drill pipe, at least one portion 8 substantially rectilinear and parallel to this drill pipe 1. The endless chain carries gripping pads (not shown) which, along the portion 8 of the endless chain 6, contact the external wall of the drill pipe 1. The gripping pads may be of any known-type and, in particular, be deformable so as to adapt themselves to the shape of the cross section of the elongated member or drill pipe 1.
Gripping the drill pipe 1 can be achieved by moving driving means 7 located on both sides of the pipe 1 towards each other in a direction perpendicular to the drill pipe axis.
To this end the frame 3 is provided with guideways 9 which cooperate with rollers 10 carried by side plates 11, integral with the driving elements 7.
Double acting hydraulic jacks 12 have one of their ends integral with the frame 3, and their other end detachably secured to the side plates 11.
The operation of the device is as follows:
The frame 3 being positioned, at the desired location the rollers 10 are inserted into the guideways 9 of the frame 3. The side plates 11 and the jacks 12 are made integral with each other. The jacks 12 are supplied with low pressure hydraulic fluid, so as to bring the pulling elements 7 into contact with the drill pipe 1, until the gripping pads are pressed against the external surface of the drill pipe which passes through the central opening of the frame 2. In this way gripping the drill pipe can be-perfectly achieved irrespective of the diameter of pipe 1.
By means of a illustrated in FIG. la device for controlling position of each pulling element 7, with respect to the vertical axis of the frame 3, it is possible to ascertain that clamping the drill pipe 1 by the pulling element 7 is achieved when the longitudinal axis of the drill pipe 1 is in line with the vertical axis of the frame 3. Each pulling element 7 is integrally connected with a slider C,C of conventional potentiometers P,P', re- 'spectively, comprising two terminals connected to the terminals of an electric current source E. One of the terminals of each potentiometer and slider is connected to an indicating device R having four input terminals, two such terminals for each pulling band 7 of a single pair. The indicating device R has two needles I,I for indicating the respective positions of the sliders C,C, i.e., the respective positions of the two pulling bands 7 with respect to the axis X-X' of the elongated element 1. The needles, 1,1 are opposite to each other when the two bands 7,7 are symmetrical with respect to axis X-X'.
The gripping force is obtained by increasing the pressure of the hydraulic fluid feeding the jacks 12 until this pressure reaches the value corresponding to the desired clamping force.
Driving means, such as, for example, hydraulic engines, actuate the driving sprocket wheels 4 which drive the endless chain means in the direction corresponding to the desired displacement of the drill pipe.
During the operation of the pulling elements 7, possible variations in the pipe diameter are absorbed by the hydraulic jacks 12. Since the later are fed with a hydraulic fluid under a constant pressure, any diameter variation of the drill pipe 1 will result in a corresponding translation of the pulling elements 7, without variation in the gripping force exerted on the drill pipe by the gripping pads carried by the endless chains 6.
In the case where a pulling element 7 is defective, such element can be quickly replaced. To this end, the jacks 12 are supplied with pressurized hydraulic fluid so as to displace or to translate the defective element to the position shown in dotted line in FIG. 1. The jacks 12 and the side plate 11 are then released from each other.
By using suitable handling means, the defective pulling element 7 is removed and immediately replaced by another identical element.
After the jacks have been made integral with the side plate 11 of the new pulling element, clamping of the pipe is achieved in the abovedescribed manner.
FIG. 2 illustrates a preferred embodiment of the de- I vice according to the invention, which can be used, for example, for handling a flexible drill pipe. This device comprises a plurality of pulling units 3 a, 3 b, 3 e, such as those illustrated in FIG. 1, which are connected in series, each of these units are exerting a fraction of the overall pulling force required for displacing the flexible pipe.
In this way, the variation in the tension of the flexible pipe 1, between the inlet and the outlet of each pulling unit is smaller than that which would be required in the case of use of a single pulling for handling the same load, thus allowing a reduction in the wear due to the relative sliding between pipe 1 and the gripping pads.
The hydraulic motors 13 a, 13 b and 13 0, driving the pulling means are fed in parallel through hydraulic pipes 14 a, 14 b and 14 c with a fluid under constant pressure, so that, as the torques developed by the motors are constant, the pulling forces exerted by each pulling means 7 a, 7 b and 7 c are also constant.
By the above-described arrangement an automatic adjustment of the running speed of the flexible pipe 1 at the level of each pulling element, results so as to compensate for the lengthening of the flexible pipe resulting from the pulling forces.
FIG. 3 diagrammatically illustrates another device permitting a compensation of possible variations in the external diameter of the flexible pipe, without causing any substantial change in the gripping force applied to the pipe through the gripping pads.
The endless chain 6 is constituted by the links 15 a, 15 b, 15 c, and so on which carry the gripping pads 16 a, 16 b, 16 c and so on respectively.
The endless chain 6 carries a guideway 17 which. along the portion 8 of the endless chain, contacts the rollers 18 a, 18 b, 18 c and so on rotatable about their axes carried by the piston rods 19 a, 19 b, 19 c and so on of the jacks 20 a, 20 b, 20 c and so on integral with the element 7.
Each jack is fed with hydraulic fluid under constant pressure through a pipe 21.
In particular the clamping jacks 20 a, 20 b, 20 c, and so on are supplied with fluid, in parallel with the jacks 12 (FIG. 1), so that, when the diameter of the elongated member 1 varies, the jacks 12 cause, as previously indicated, a displacement of the elements 7, the gripping pads remaining then in contact with the elongated member 1, under the action of the jacks, such as 20 a, 20 b, 20 c, and so on.
Changes can be made without departing from the spirit and scope of the present invention.
In particular, it is possible to provide each pulling element with safety means measuring, for example, the gripping force exerted by each endless chain on the drill pipe etc., so as to detect any abnormal condition in the operation of the device according to the invention.
What we claim is:
l. A device for continuously pulling an elongated member, comprising frame means provided with a passageway for the elongated member, said passageway having an axis, a series of pulling means carried by said frame means and arranged along said axis, each of the pulling means comprising at least two endless pulling devices carrying gripping pads, guide means provided in said frame means for each endless pulling device, each endless pulling device being provided with hydraulic jack means releasably connected to said endless pulling device and carried by said frame means, said hydraulic jack means being provided for reversibly displacing said endless pulling device from a position spaced from said axis to a gripping position closer to said axis, first hydraulic pipe means connected to each of said jack means for applying hydraulic pressure thereto, and means for synchronizing said pulling devices including a plurality of hydraulic motors operatively connected to each of said pulling devices, respectively, and second hydraulicpipe means comprising supply pipes for connecting said hydraulic motors in parallel to a common source of pressurized hydraulic fluid.
2. A device according to claim 1, wherein each endless pulling device is removably mounted in said frame means and is slidable along said guide means.
3." A device according to claim 1, wherein each of said pulling means comprises at least a pair of endless pulling devices symmetrically located about said axis.
4. A device according to claim 1, including means for controlling the position of each pulling device relative to said axis.