Abstract:
A strap pipe wrench for driving an object having a generally cylindrical shape includes a handle which extends along a longitudinal axis, a connecting member which is movable relative to the handle in a direction parallel to the longitudinal axis, and a strap formed in a loop and having two opposing end portions which cooperate with two zones integral with the handle when the strap surrounds the object tightly, the two opposing end portions of the strap being attached to the connecting member, a displacement device for displacing said connecting member, and enabling the size of the loop of the strap to be adjusted and the strap to be tensioned when it surrounds the object tightly, and a shoe disposed between the two zones for abutment on the object, the shoe having an abutment face of generally arcuate shape.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to a strap pipe wrench for driving an object having a generally cylindrical shape, of the type comprising:
         a part forming a handle which extends according to a longitudinal axis;   a strap, especially a metal strap, in loop form, the two opposing end portions of which cooperate with two zones integral with the handle when the strap surrounds said object tightly;   a connecting member which is movable relative to the part forming a handle according to the longitudinal axis thereof, the two opposing end portions of the strap having ends that are integral with said member;   means for displacing said connecting member, enabling the size of the loop of the strap to be adjusted and the strap to be tensioned when it surrounds said object tightly; and   the part forming a handle being equipped, between said two zones, with a shoe for abutment on said object, the abutment shoe not being connected to the strap and having an abutment face of generally cylindrical shape with generatrices that are perpendicular to the general plane of the strap.       

     The invention is applicable in particular to oil filter wrenches for motor vehicles, and reference will be made to this application in the following. 
     (2) Description of Related Art 
     Examples of such strap pipe wrenches are described in document FR-A-1.570.027 and in documents FR-A-2.779.372 and FR-A-2.779.373 in the name of the Applicant. 
     In those known strap pipe wrenches, a screw/nut system allows the strap to be connected to the handle. Because the nut is connected to the strap, a rotary movement of the screw allows the user to adjust the working length of the strap manually by means of a wheel. The phases of adjusting the strap are lengthy and repetitive. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the invention is to facilitate the adjustment of the strap in a particularly ergonomic manner. 
     To that end, the invention relates to a strap pipe wrench of the type mentioned above, characterised in that said connecting member is movable between at least one first position corresponding to the position of the strap, in the loose state, surrounding said object with clearance, and a second position corresponding to the position of the strap, in the tensioned state, surrounding, tightly and firmly, said object in abutment on the abutment face of the shoe, and the displacement means comprising:
         elements for locking said connecting member, said locking elements being suitable, in the active position, for keeping said member fixed relative to the part forming a handle when said member is in the first position;   a resilient biasing element, especially a compression or draw spring, which urges said member towards the second position; and   a control member suitable for deactivating said locking elements.       

     According to other features, the strap pipe wrench according to the invention can have one or more of the following features, taken in isolation or in all technically possible combinations:
         the control member comprises a rod which is integral with the part forming a handle and extends inside that part according to its longitudinal axis, said rod being suitable for engaging with the locking elements at least when the connecting member is in the first position;   the locking elements comprise at least one piston, preferably two pistons, carried by the connecting member, the or each piston being in abutment in a groove formed on the rod when the connecting member is in its first position;   the or each piston is urged resiliently so that it tends to engage in the groove of the rod;   the rod comprises at least one rack in which there engages at least one retaining finger carried by the connecting member when the latter is in its second position;   the rod comprises four faces having two racks in the form of saw-teeth and two flat areas, the racks and the flat areas being arranged opposite one another in pairs, and the connecting member comprises two retaining fingers each engaging with a rack;   the rod is mounted for rotation relative to the connecting member and to the handle about an axis of rotation that is substantially coincident with the longitudinal axis of the handle, between a locking position corresponding to the first position of the connecting member, in which the or each piston enters the groove, and a release position, arranged 90° from the locking position of the rod, corresponding to the second position of the connecting member, in which the or each piston is in abutment on a flat area of the rod;   the control member also comprises an activation lever which enables said rod to be rotated from its locking position to its release position and vice versa;   the rod is mounted to be movable in translation towards the proximal end of the handle, against a resilient biasing element, so as to tend to displace the connecting member integrally in order to increase the tension of the strap surrounding, tightly and firmly, said object in abutment on the abutment face of the shoe;   the activation lever allows said rod to pass from its second position to a third position corresponding to the displacement of said rod in translation;   the abutment shoe is adapted to produce a ratchet effect for unidirectional driving of said object, driving resulting from a toggle lever effect;   the abutment shoe is mounted to tilt relative to the handle about a geometric axis associated with the handle and perpendicular to the general plane of the strap, the axis being arranged so that, the shoe and the strap both being applied with clamping to said object, action on the handle exerted in a first direction causes driving of the object and, when exerted in the other direction, causes the shoe and the strap to slide on the object;   said geometric axis is offset laterally relative to the longitudinal axis of the handle, the direction of the offset being said first direction;   the abutment shoe is mounted to tilt freely and with a limited amplitude about said axis; and   the abutment shoe has an abutment face whose coefficient of friction is markedly higher in one direction of rotation of the wrench than in the other direction, for example by virtue of sloping saw-teeth provided on the abutment face.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention and the advantages thereof will be better understood upon reading the following description, which is given solely by way of example and with reference to the accompanying drawings, in which: 
         FIG. 1  is an outside front view of the strap pipe wrench according to the invention, with the strap positioned loosely around an oil filter that is to be unscrewed; 
         FIG. 2  is an exploded perspective view of the strap pipe wrench according to  FIG. 1 ; 
         FIG. 3  is a front view of the wrench of  FIG. 1  in which part of the handle has been removed; 
         FIG. 4  is an exploded perspective view of the connecting member movable relative to the handle of the strap pipe wrench; 
         FIG. 5  is a detail view in longitudinal section according to plane V-V of  FIG. 4 ; 
         FIG. 6  is a detail view in longitudinal section according to plane VI-VI of  FIG. 4 ; 
         FIG. 7  is a view in transverse section according to line VII-VII of  FIG. 5 ; 
         FIG. 8  is a view in transverse section according to line VIII-VIII of  FIG. 6 , showing a first position of the central rod; 
         FIG. 9  is a view analogous to  FIG. 3  after tight adjustment of the strap around the oil filter, the central rod being in a second position; 
         FIG. 10  is a view analogous to  FIG. 6  showing the central rod in the second position; 
         FIG. 11  is a view analogous to  FIG. 8 , the transverse section being taken according to line XI-XI of  FIG. 10 ; 
         FIG. 12  is a view analogous to  FIGS. 3 and 9 , in which the central rod is in a third position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The strap pipe wrench  10  shown in  FIGS. 1 to 12  is intended principally for unscrewing, and secondarily, by turning the wrench round, for screwing in, objects  11  having a generally cylindrical shape, especially oil filters, the diameters of which can vary within a wide range, for example, in the embodiment shown, from 64 to 106 mm. 
     In order to describe the wrench  10  more easily, it will be assumed to be oriented as shown in the drawings, extending according to a longitudinal axis X-X with the filter  11 , of axis O, situated above the handle of the wrench. 
     In  FIG. 1 , the strap pipe wrench  10  comprises a handle  12  having a distal portion  13  that forms a cap, the sides of which are parallel to the plane of the drawing, and a proximal portion  14 . 
     A band  15 , especially a band made of metal and forming a strap in the form of a loop, has two end portions  16  and  17  which are connected to the handle  12 . A shoe for abutment on the filter  11 , having the reference numeral  18 , is articulated in the distal portion  13  forming a cap and is arranged freely between the two end portions of the strap  15 . 
     The shoe  18  is wholly independent of the strap and is as described in documents FR-A-2.779.372 and FR-A-2.779.373. In particular, it is mounted to tilt freely and with limited amplitude about an axis associated with the handle  12  and perpendicular to the general plane of the strap  15 . It has an upper abutment face  18 A of generally cylindrical shape with generatrices that are perpendicular to the general plane of the strap  15 , which is the plane of the drawing. The guiding line of the cylinder can be in a very wide V-shape, as shown, or alternatively, by way of variation, it can be circular, for example having a radius corresponding to the smallest radius of the filters to be handled. The face  18 A additionally has the form of saw-teeth sloping to the right in  FIG. 1 , for a reason which will become apparent hereinbelow. 
     A seat  19  connects the cap  13  to the main portion of the handle  12 . 
     As is shown in  FIG. 2 , the handle  12  is composed of two molded half-shells  20  and  21  which are fitted together, for example, by screws  22  according to a vertical joining plane situated in the mid-plane of the strap. 
     The strap  15  has ends  23  and  24  on the respective end portions  16  and  17 . Screws  26  connect the ends  23  and  24  of the strap  15  rigidly to a connecting member  28 . A rod  30  having an upper end  32 , a lower end  34  and an intermediate portion  36  passes through the connecting member  28 . The upper end  32  is smooth and of reduced diameter; the lower end  34  is also smooth and has a diameter greater than that of the end  32 . 
     The intermediate portion  36  is of generally cylindrical shape having four faces, which form two diametrically opposite racks  38  and two flat areas  40  which are also diametrically opposite. 
     A through-bore  42  is arranged transversely to the rod  30  at the lower end  34 , and a shoulder  44  connects the intermediate portion  36  to the lower portion  34 . 
     A helical compression spring  46  is arranged coaxially with the upper portion  32  of the rod  30 . The ends of the spring  46  are in abutment on the one hand, in its lower portion, on the connecting member  28  and on the other hand, in its upper portion, on inside parts of the seat  19  of the half-shells  20  and  21 . 
     A washer  48  is arranged in the region of the shoulder  44  and serves as an abutment surface for a conical compression spring  50  arranged coaxially with the lower portion  34  of the rod  30 . 
     A washer  52  having a diameter larger than that of the washer  48  is arranged in the bottom of receivers  54  and  55  formed in the region of the proximal portion  14  of the sleeve  12  on each of the half-shells  20  and  21 . 
     An activation lever  56 , the function of which will be described more precisely hereinbelow, is arranged in the receivers  54  and  55 . A pin  58  arranged inside the transverse bore  42  articulates the lever  56  on the lower end  34  of the rod  30 . 
     Each side of the cap  13  has two concentric blind receivers, namely a circular receiver  60  and an arc-shaped receiver  61 . 
     The shoe  18  is articulated in the cap  13  about a pin  62  whose axis, which is offset relative to the longitudinal axis X-X, bears the same reference numeral. The pin  62  protrudes from each side of the shoe and rotates in the receivers  60  provided in the sides of the cap  13 . A pin  63  also protrudes from each side of the shoe, its ends being received in the arc-shaped receivers  61  provided in the sides of the cap  13 . 
     The seat  19  of each shell  20 ,  21  has on the inside a bearing  64  which is to receive the upper end  32  of the rod  30 . 
     Support slots  65  are arranged in a sloping manner converging towards the proximal end  14  of the handle  12 . The two opposite end portions  16  and  17  rest on the outside face of the two support slots  65  when the strap surrounds the filter  11  tightly. The slots  65  open on the one hand into the cap  13  and on the other hand into a cavity  66  formed longitudinally inside each of the half-shells  20  and  21 . 
     The cavities  66  extend, on the inside, over approximately three-quarters of the main portion of the handle  12  so as to form, once the half-shells  20  and  21  have been fitted together, a receiver for receiving the connecting member  28  to which the ends of the strap  15  are fixed. Each receiver  66  is delimited in the region of the proximal portion  14  of each half-shell  20 ,  21  by a wall  67 . The enlarged lower turn of the conical spring  50  rests on the wall  67 . A bore  68  passes through the wall  67  and serves as a bearing for the lower end  34  of the rod  30 . 
     As is shown in  FIG. 3 , the connecting member  28  being positioned in the internal receivers  66 , the ends  32  and  34  of the rod  30  are mounted in the bearings  64  and  68  of the shell  22  so that activation of the lever  56  enables the rod  30  to rotate about the longitudinal axis X-X. 
     In this configuration, the helical spring  46  is compressed virtually until its turns are contiguous. The upper end of the spring  46  is in abutment on a shoulder  69  formed inside the seat  19 , the shoulder being formed close to the bearing  64 . The lower end of the conical spring  50  is in abutment on the wall  67  of the proximal end of the half-shell  22 . 
     In this configuration, the connecting member  28  is locked in the top position, as will be seen hereinbelow. 
       FIG. 4  shows the connecting member  28  in detail, the other parts of the strap pipe wrench  10  having been hidden. The connecting member  28  comprises a rigid body  70  of generally cubic shape. The body  70  has opposing pairs of lateral faces  72  and  74 , a face  72  being orthogonal to a face  74 . The body  70  also has an upper face  76  and a lower face  78 . 
     A bore  80  passes through the body  70  longitudinally according to the direction of the axis X-X and opens at the upper and lower faces  76  and  78 . The bore receives the rod  30  for rotation according to the longitudinal axis X-X and for translation according to that same axis. 
     A circular rib  82 , which protrudes from the upper face  76 , prolongs the bore  80 . The outside wall of the rib  82  is of such a size as to receive, with slight clearance, the inside diameter of the turns of the helical spring  46  ( FIG. 5 ). 
     The lateral faces  72  cooperate with the ends  23  and  24  of the strap  15 . Threaded bores  84 , which are transverse to the axis X-X and are formed in the lower portion of the faces  72 , allow the fixing elements  26  to be screwed and accordingly enable the strap  15  to be attached to the connecting member  28 . 
     Smooth bores  86 , which are transverse to the axis X-X, are provided in the upper portion of the faces  72  and open into the axial bore  80 . 
     Cylindrical pistons  88  having a shape complementary to that of the transverse bores  86  are able to slide in the transverse bores  86 . 
     Each piston  88  has a blind central bore  90  in which there engages one of the two ends  92  of a C-shaped pin  94 . 
     A partially circumferential groove  96  receives the main portion of the pin  94 , the pin  94  acting as a spring which tends to hold the pistons  88  in the transverse bores  86 . 
     The lateral faces  74  each have a hollow receiver  100  for receiving a fixing plate  102 . Smooth bores  104 , which are transverse relative to the axis X-X, formed in the lower portion of the faces  74 , each receive, in a sliding manner, a cylindrical retaining finger  106  having a blind central bore  108  in which there is received one end of a helical spring  110 , the other end of the helical spring  110  being in abutment against the fixing plate  102 . 
     Threaded bores  112 , transverse relative to the axis X-X, formed in the upper portion of the faces  74  permit screwing of the fixing elements  114  and, accordingly, enable the fixing plates  102  to be attached to the connecting member  28 . 
     Threaded bores  116  arranged parallel to the longitudinal axis X-X are provided, starting from the lower face  78  of the body  70 , opposite the threaded bores  104  and open into those bores. A screw  118  screwed into each of the bores  116  has a nose  120  for limiting the sliding movement of the corresponding retaining finger  106  ( FIG. 6 ). 
     As is shown in  FIG. 5 , the connecting member  28  is suitable for assuming a first position corresponding to the position of the strap in the loose state, surrounding the filter with clearance ( FIG. 1 ). 
     In that first position, the pistons  88  cooperate with a groove  130  which is formed between the upper portion  32  and the intermediate portion  36  of the rod  30  and is delimited in the lower portion by lateral faces  132  substantially perpendicular to the longitudinal axis X-X. The ends  92  of the pin  94  urge the pistons  88  to engage radially in the bottom of the groove  130 . In that same position ( FIG. 7 ), the flat areas  40  are oriented parallel to the pistons  88 . The spring  46 , in the compressed state, urges the connecting member  28  towards the proximal end  14  of the handle, the lateral faces of the pistons  88  being in abutment with the lower lateral faces  132  of the groove  130 . The connecting member  28  is accordingly locked in the top position relative to the handle  12 . 
     As is shown in  FIG. 6 , when the connecting member  28  is in the first position, each of the retaining fingers  106  urged by the springs  110  has a lower groove  134  which is formed on its outer periphery and extends perpendicularly to the longitudinal axis X-X. Each groove  134  has a shape complementary to that of a nose  120 . The nose  120  thus limits the path of the corresponding retaining finger  106  against the action of the spring  110  and, in particular, holds the corresponding finger  106  in a position in which it is in radial abutment against the rear face of the groove  134 . 
     Each retaining finger  106  has, opposite the bore  108  in engagement with one of the ends of the spring  110 , at least one tooth  140  in the form of a saw-tooth. 
     In the first position of the connecting member  28  shown in  FIG. 7 , the pistons  88  are in abutment at the bottom of the groove  130  against a surface having a substantially cylindrical cross-section, the diameter of which is substantially equal to the distance between the flat areas  40  of the rod  30 . 
     In that same position of the connecting member  28  shown in  FIG. 8 , each tooth  140 , cut straight, of the retaining fingers  106  is arranged opposite and at a distance from the flat areas  40  of the rod  30 . The teeth of the racks  38  are in turn cut to be rounded and are arranged substantially at 90° from each tooth  140  of the retaining fingers  106 . 
     Accordingly, in the first position of the connecting member  28 , only the pistons  88  form elements for locking the connecting member  28  on the rod  30 , the retaining fingers  106  not being in engagement with the racks  38  of the rod  30 . The connecting member  28  is not able to slide according to the direction of the longitudinal axis X-X. 
     That first position of the connecting member  28  is readily obtained by previously positioning the activation lever  56  as shown in  FIGS. 1 and 3 , that is to say in such a manner that the pistons  88  are opposite the flat areas  40  of the rod  30 . The user then grasps the handle  12  with one hand and the strap  15  with the other hand and acts manually on the strap  15  by pulling it outwards in order to increase the length of the loop extracted from the handle  12 . The user of the strap pipe wrench  10  continues this action until the pistons  88  come into engagement with the groove  130 . Of course, the number of grooves can be adapted to a given number of strap lengths extracted from the handle of the strap pipe wrench. 
     The connecting member  28  is movable between this first position and a second position corresponding to the position of the strap in the tensioned state surrounding, tightly and firmly, the filter in abutment on the abutment face of the shoe, as is shown in  FIG. 9 . In order to pass from the first position of the connecting member  28  shown in  FIG. 3  to the second position of the same connecting member shown in  FIG. 9 , the user turns the rod  30  through an angle of 90° relative to the longitudinal axis X-X by means of the activation lever  56 . 
     That 90° rotary movement has the effect of deactivating the locked state between the pistons  88  and the groove  130 . The pistons  88  are, in fact, then positioned opposite the flat areas  40  of the rod  30 . Under the release action of the compression spring  46 , the connecting member  28  slides freely in the direction of the longitudinal axis X-X towards the proximal end  14  of the handle  12 , the pistons coming into abutment against the flat areas  40  of the rod  30 . 
     In that second position of the connecting member  28 , the spring  46  is partially relaxed. The spring  50  acts as a shock absorber during passage from the first position to the second position of the connecting member  28 . 
     This rotary movement of the rod  30  has also had the effect of bringing the teeth of the rack  38  into engagement with each tooth  140  of the retaining fingers  106 , as is shown in  FIG. 10 . 
     During the sliding movement of the connecting member  28 , which tends to move towards the proximal end  14  of the handle  12  under the effect of the relaxation of the spring  46 , each tooth  140  of the retaining fingers  106  follows the saw-tooth form of the racks  38 , which leads to an alternative sliding movement of the retaining fingers  106  transversely to the longitudinal axis X-X, against the springs  110  and with snapping on passing each rack tooth. 
     When the strap  15  and the shoe  18  are both fitted on the filter  11 , with clamping, and the filter  11  is locked firmly between the strap and the shoe, each tooth  140  of the holding fingers  106  is positioned, with locking, on a tooth of the racks  38  under the action of the spring  46 , which maintains the second position of the connecting member  28 , with a clamping force on the filter that is determined by the strength of the spring  46 . 
     As is shown in  FIG. 11 , in that second position of the connecting member, the straight teeth  140  of the retaining fingers  136  are partially in engagement with the curved teeth of the racks  38  under the action of the springs  110 . 
     Accordingly, the second position of the connecting member  28  is easily obtained starting from the first position of the connecting member  28  by simple rotation of the activation lever  56 , in particular a 90° rotation, from the position of the activation lever  56  as shown in  FIGS. 1 and 3  to the position of the activation lever  56  as shown in  FIG. 9 . 
     From that second position of the connecting member  28 , the user pushes the handle  12  to the right (arrow F 1  in  FIG. 9 ). The saw-teeth of the abutment face  18 A of the shoe, the coefficient of friction of which is markedly higher in one direction of rotation of the wrench than in the other direction, firmly engage with the filter, and that action drives the wrench and the filter, as a single unit, in rotation about the axis O ( FIG. 9 ). 
     After a certain angle of anticlockwise rotation of the filter, for example limited by adjacent engine components, the user pushes the handle  12  to the left, that is to say in the opposite direction to that described hereinbefore (arrow F 2  in  FIG. 9 ). 
     Given the orientation of the saw-teeth of the shoe, sliding of the tool as a whole about the filter  11 , clockwise, is obtained. 
     The wrench  10  accordingly has a ratchet effect, which allows a to-and-fro movement of the handle to be carried out several times in order to unscrew the filter  11  by a plurality of successive angles. The unidirectional driving of the wrench  10  is the result of a toggle lever effect, the point of articulation of the toggle lever being the geometric axis  62 . 
     In  FIG. 12  it will be seen that the lever  56  has a cap between the sides  150  of which there is received the lower end  34  of the rod  30 . The pin  58  connects the sides  150  to the lower end  34  of the rod  30 . 
     This arrangement allows the activation lever  56  to rotate about the pin  58 , the axis Y-Y of which is substantially perpendicular to the longitudinal axis X-X. 
     During the rotary movement which tends to rotate the activation lever  56  about the axis Y-Y, the ends of the sides  150  are supported on the washer  52  arranged in the receivers  54  and  55  of the half-shells  20  and  21 . By means of a cam effect of the lever  56 , the rod  30  is pulled in translation towards the proximal end  14  of the handle  12 , according to the direction of arrow F 3  in  FIG. 12 , against the action of the spring  50  in abutment against the washer  48  and the wall  67 . 
     Because the connecting member  28  has remained in engagement with the rod  30 , the translational movement tends to displace the connecting member  28  integrally towards the proximal end  14  of the handle  12  in order to increase the tension of the strap  15  surrounding, tightly and firmly, the filter  11  in abutment on the upper face  18 A of the shoe  18 . 
     The increase in the tension of the strap  15 , which is the result of the preceding operation, tends to cancel out the ratchet effect that the abutment shoe  18  is capable of producing for unidirectional driving of the filter  11 , as described in patent applications FR-A 2 779 372 and FR-A-2 779 373 cited in the preamble and which are to be taken into account in their totality in the present patent application. 
     Once the maintenance operation has been carried out on the oil filter, the user removes the strap pipe wrench  10  from the filter  11 . To that end, he returns the activation lever  56  to its initial position corresponding to that of  FIGS. 1 and 3  and pulls on the strap  15  in order to loosen it and bring the connecting member  28  into its top locking position. The worn filter which has been removed is then freed from the grasp of the strap  15 . The strap pipe wrench is again ready for a fresh maintenance operation. 
     By virtue of the invention, adjustment of the working length of the strap and tensioning of the strap, the strap tightly surrounding the oil filter, are facilitated, which makes the tool particularly ergonomic.