Adjustable cable sheath terminal

Abstract: The invention relates to an adjustable cable sheath terminal which can be used particulary in the automobile industry. To solve the problems which arise form the adjustment of the length of cables having a protective sheath an adjustable cable-sheath terminal is provided which is constituted by an essentially cylindrical hollow main body (CP) provided with mechanical means (AN) for anchorage to a fixed point, by an adjusting rod (RE) having an external screw thread (1) and which, fixedly attached at one of the ends thereof to the sheath (2) of the cable (3) whose length is to be adjusted, may slide over a sufficient distance inside said main body (CP), and by a lock nut (7A) which engages the retaining fingers (GR) which may firmly retain said adjusting rod (RE) in the desired position.

Description: Technical Field of the Invention The present invention relates to an adjustable cable sheath terminal constituted by an essentially cylindrical hollow main body provided with mechanical means for anchorage to a fixed point, by an adjusting rod having an external screw thread and which, fixedly attached at one of the ends thereof to the sheath of the cable whose length is to be adjusted, may slide over a sufficient distance inside said main body, and by retaining fingers which may firmly retain the said adjusting rod in the desired position. These terminals are particularly used in the automobile industry. Background of the invention Cables provided with protective sheaths or with sheaths adapted to any other function or purpose, are widely used in all kinds of mechanical applications where the transmission of forces or of movements between the source and the receiver must be carried out with non rigid linkings. Exemplary of the application of such cables are, among others, the control cables used in the automobile industry which, among other functions, connect the clutch pedal to the corresponding mechanism, interconnections of the brake system, as link between the gear change lever and the gear box, the link between the bonnet opening control, normally the engine bonnet and the latter, and the link between the speedometer on the vehicle dashboard and the gear box. A crucial factor for the perfect operation of the force transmission device using the cable in the above-mentioned examples is the need to have the appropriate length of cable in each particular case. In view of the peculiar features of the installation of control cables in motor vehicles and the features corresponding to each type of cable with its specific connection and sheath terminals, the aforesaid condition makes it necessary to have recourse to more or less constructionally and operatively complex devices allowing the length of the sheathed control cable to be adjusted at the appropriate points, depending on the structure of the vehicle itself or on assembly conditions. From GB-A-2 176 861 there is known an adjustable cable sheath terminal constituted by an essentially cylindrical hollow main body provided with mechanical means for anchorage to a fixed point, by an adjusting rod having an external screw thread and which, fixedly attached at one of the ends thereof to the sheath of the cable whose length is to be adjusted, may slide over a sufficient distance inside said main body and by retaining fingers which may firmly retain the said adjusting rod in the desired position. As an example of the above mentioned devices there may be cited the device of ES-A-8803905, "Control cable tension selfadjusting device", and that of ES-A-8901238, "Adjustable connecting device". In the former ES-A-8903905, the sheathed cable length is adjusted automatically by a spring which, initially compressed, is released when the device is used; and in the latter, ES-A-8901238, the ajdustment of the sheathed control cable length is effected manually without using springs. In both cases, i.e. in ES-A-8803905 and ES-A-8901238, both the large number of component parts of the devices and their respective structurs and designs have the drawback of a high production cost and limited operative flexibility which limit their possibilities of use. Summary of the Invention To provide a new solution to the problems raised by the adjustment of the length of cables having a protective sheath, an adjustable cable sheath terminal whose structure and operative design are novel is disclosed. The adjustable cable sheath terminal of the invention is characterized in that it is further constituted by a lock nut which engages the retaining fingers, said lock nut being provided on the outer surface of the main body and being positioned to cover radial through holes formed in said main body, the lock nut being provided in the interior thereof with tightening projections for pressing against the retaining fingers, said retaining fingers being housed in said radial through holes of said main body. The main body, which is made from materials having mechanical properties adequate for the intended purpose, is provided with a sufficient number of radial through holes preferably disposed on a single plane perpendicular to the longitudinal axis of the main body, for adjustably housing the retaining fingers which, being of the same number as the radial holes, can retain said adjusting rod attached to the cable sheath in the desired position. The outer surface of the main body is also formed with longitudinal projections for correctly positioning the lock nut relative to the adjusting rod retaining fingers and with a sufficient number of appropriately dimensioned recesses for setting the position of the said lock nut preventing it from extemporaneously coming out of or changing its locked position. The through hole characterizing the main body of the terminal of the invention and through which the adjusting rod attached to the cable sheath can slide over a sufficient distance, is provided with two portions of different diameters which may have a different length, on one of which the adjusting rod can snugly slide, while the other portion, which is of larger diameter, comprises projections limiting the maximum movement of the adjusting rod and preventing it from coming out of the main body. A particularly remarkable feature of the terminal of the invention consists of the fact that the position of the adjusting rod, which is fixedly attached at one end thereof to the cable sheath inside the main body and which precisely caters for the adjustment of the length of the sheathed cable, is controlled manually or automatically by way of a spring which is incorporated inside said main body. The larger diameter portion of the main body through hole, through which the adjusting rod attached to the cable sheath can slide, is dimensioned such that it can conveniently house a spring which, under compression automatically adjusts the sheathed cable length. The spring is preferably disposed coaxially relative to the adjusting rod and presses at one end thereof against the flat surface defining the change of section of the main body through hole, said flat surface being perpendicular to the longitudinal axis of the through hole and, at the other end thereof, presses against the adjusting rod. The adjusting rod, which is provided with an external screw thread extending over a sufficient distance and is fixedly attached at one end thereof to the cable sheath, is provided with a longitudinal through hole through which the portion of sheathless cable crossing through the main body may conveniently slide, the said end having a preferably annular projection which coacts with the projections formed inside the main body. The retaining fingers for the adjusting rod are essentially parallelepipedic, two opposing surfaces thereof being slightly curved, one of which is provided with a screw thread of the same pitch as the screw thread formed on the outer surface of the adjusting rod, the retaining fingers also being provided with ejector springs, such as corresponding resilient projections which permanently urge said fingers radially outwardly, to establish the appropriate rest, i.e. released position thereof, in the radial through holes formed in the main body. The retaining fingers of the adjusting rod are attached to a concentric open perimeter ring of resilient material, acting as ejector springs, i.e. in replacement of the said resilient extensions. The lock nut operating on the retaining fingers of the adjusting rod is provided in the interior thereof with longitudinal tightening projections for pressing, after an appropriate rotation of the lock nut, against the said retaining fingers and overcoming the permanent action of the ejector springs, to which end the number and position thereof are the same as the number and position of the radial through holes formed in the main body in which said retaining fingers are located, there also being in the interior of said lock nut positioning projections, the number and position of which are also the same as the number and position of the recesses formed on the outer surface of the main body for setting the position of the lock nut in the locking or retaining position of the adjusting rod. The lock nut is also provided on the outer surface thereof with a knurled portion or a number of alternating recesses of appropriate dimensions which are for facilitating the operations of setting the length of the cable provided with protective or other sheath for the operative. For ensuring correct guiding of the cable, the end of the adjusting rod opposite to the one fixedly attached to the cable sheath is optionally provided with a tubular guide through which the sheathless portion of cable slides. Brief Description of the Drawings The adjustable cable sheath terminal of the invention is illustrated in the sheets of drawings accompanying the present description. In the drawings: Figure 1 is a cross section view of the terminal of the invention, showing the adjustment position in which the sheathed cable length is maximum. Figure 2 is a cross section view on the line II-II of Figure 1. Figure 3 is a cross section view of the terminal of the invention, showing an intermediate adjustment position of the sheathed cable length. Figure 4 is a cross section view on the line IV-IV of Figure 3. Figure 5 is a cross section view of the terminal of the invention, incorporating a spring for automatic adjustment, showing the adjustment position in which the sheathed cable length is maximum. Figure 6 is a cross section view on the line VI-VI of Figure 5. Figure 7 is a cross section view of the terminal of the invention, incorporating a spring for automatic adjustment, showing an intermediate adjustment position of the sheathed cable length. Figure 8 is a cross section view on the line VIII-VIII of Figure 7. Figure 9 is a cross section view of the terminal of the invention, incorporating a spring for automatic adjustment, showing the adjustment position in which the sheathed cable length is minimum. Detailed Description of the Embodiment The adjustable cable sheath terminal of the invention described here as an exemplary embodiment is constituted, as shown mainly in Figures 1, 3, 5, 7 and 9 of the attached sheets of drawings, by the main generally cylindrically shaped hollow body CP provided with mechanical means AN for anchorage thereof to a fixed point, by an adjusting rod RE having an external screw thread 1 and which, fixedly attached at one end thereof to the sheath 2 of the cable 3 whose length is to be adjusted, may slide over a sufficient distance in the interior of the main body CP and by a lock nut TA which engages the retaining fingers GR which may retain the said adjusting rod RE in the desired position. In the present embodiment the mechanical means AN are constituted by the radial projection 4 forming one end of the main body CP. The radial projection 4 defines a U-shaped housing 4a of appropriate dimensions so that, in engagement with the means disposed on the vehicle structure (which have not been shown in the attached sheets of drawings) forming the fixed point, the terminal of the invention may be fixedly attached to the said fixed point, preventing any change of position relative to the intended operating position. The main body CP is provided with two radial through holes 5 disposed, as shown in all the Figures of the attached sheets of drawings, on a single plane perpendicular to the longitudinal axis of the terminal of the invention. The radial through holes 5 are dimensioned so as to be able snugly to house corresponding retaining fingers GR, whose purpose is to retain and fix the adjusting rod in the desired position, preventing extemporaneous release, as shown in detail in Figures 2, 4, 6 and 8. Figures 2, 4, 6 and 8 show how the outer surface of the main body CP is provided with the two longitudinal projections 6 the purpose of which is to position the lock nut TA correctly relative to the retaining fingers GR while the cable 3 length is being adjusted relative to the sheath 2. The main body CP is also provided with the two recesses 7, shown in Figures 1, 3, 5, 7 and 9 which, suitably dimensioned, have the mission of fixing said lock nut TA in the tightened or retained position of the adjusting rod RE, shown in Figures 3, 7 and 9, thereby preventing the terminal of the invention from coming out of or changing its position, owing to the operative conditions to which it is subjected when the vehicle is running. The main body CP is provided with the through hole 8 through which the adjusting rod RE attached to the sheath 2 of the cable 3 may slide over a sufficient distance. The through hole 8 has a first portion 8a in which the adjusting rod RE may snugly slide, while the remaining portion 8b, which is of larger diameter, contains a projection 9, the purpose of which is to limit the maximum movement of the adjusting rod RE, thereby preventing it from coming out of the main body CP, as shown in detail in Figures 1 and 5. The position of the adjusting rod RE, which is attached to the sheath 2 of the cable 3, in the interior of the main body CP, and which provides for the adjustment of the sheathed cable 2-3, may be manually controlled as shown in Figures 1 and 3, or automatically by the action of a spring 10 housed in the main body CP, as shown in Figures 5, 7 and 9. The larger diameter portion 8b of the through hole 8 of the main body CP may be dimensioned in such a way as to be able to house the spring 10 which, under compression, expands and automatically adjusts the length of the cable 3 provided with the sheath 2. The spring 10 is preferably coaxially disposed relative to the adjusting rod RE and presses, at one end thereof, against the flat surface 8p defining the change of section of the through hole 8. As shown in Figures 1, 3, 5, 7 and 9, the flat surface 8p is perpendicular to the longitudinal axis of the through hole 8. At the other end thereof the spring 10 presses against the adjusting rod RE. The adjusting rod RE is provided with a longitudinal through hole 11 through which the cable 3 may suitably slide, as shown in all the Figures of the attached sheets of drawings. The end of the adjusting rod RE fixedly attached to the sheath 2 of the cable 3 is formed by the preferably annular rim 12 which coacts with the lip 9 disposed on the larger diameter section 8b of the through hole 8 of the main body CP. In this embodiment, with a view to guiding the cable 3 correctly in the longitudinal movements thereof, the end of the adjusting rod RE opposite to the end attached to the sheath 2 of the cable 3 is provided with a seat 13 acting as housing and retaining means for the end 14 of the tubular guide 15, as shown in detail in Figures 1, 3, 5, 7 and 9 of the attached sheets of drawings. The said cable 3 may slide suitably therethrough. The tubular guide 15 is, in turn, suitably guided by the through hole 15g through which it may slide snugly. The retaining fingers GR retaining the the adjusting rod RE in the desired position are each formed by an essentially parallelepipedic body 16, two opposite surfaces of which are slightly curved. One of said surfaces is provided with a screw thread 17 of the same pitch as the external screw thread 1 of the adjusting rod RE. The retaining fingers GR are also provided with ejector springs which in the present embodiment are formed by corresponding resilient extensions 18 permanently urging said fingers radially outwardly, so as to cater for the appropriate rest, i.e. released position thereof, in the radial through openings 5 formed in the main body CP. Figures 2, 4, 6 and 8 of the attached sheets of drawings show the retaining fingers GR of this embodiment in detail in section. The number of retaining fingers GR may obviously be different from the number contemplated in this embodiment, depending on the needs raised in each particular application. Instead of the resilient extensions 18, the retaining fingers GR may be attached to a concentric ring of resilient material and having an open perimeter, acting as ejector springs. The lock nut TA operating on the retaining fingers GR is provided in the interior thereof with two longitudinal tightening projections 19 for pressing, after an appropriate rotation of the lock nut TA, against the said retaining fingers GR overcoming the permanent action of the ejector springs which, in this embodiment, are formed by the resilient extensions, to which end the number and position thereof are the same as the number and position of the radial through holes 5 formed in the main body CP in which said retaining fingers GR are housed. The interior of said lock nut TA is also provided with the two positioning projections 20, the number and position of which are also the same as the number and position of the recesses 7 of the main body CP and with which they coact as shown in detail in Figures 3, 7 and 9 of the attached sheets of drawings. The lock nut TA of this embodiment, as shown in Figures 1, 3, 5, 7and 9, is also provided with a number of alternating longitudinal recesses 21 suitably dimensioned to facilitate the operations for adjusting the length of the cable 3 provided with the sheath 2 for the operator. To this end, the series of longitudinal recesses 21 may be replaced by a knurling or even by appropriately dimensioned projections distributed over the surface of the lock nut TA. Figures 1 and 3 show the terminal of the invention in which the length of the cable 3 provided with the sheath 2 is adjusted manually. In Figure 1, the position of the lock nut TA, shown in Figure 2 allows the adjusting rod RE to slide inside the main body CP to the extent required for adjusting the length of the sheathed cable 2-3. Figure 3 shows how, once the appropriate length of the of the sheathed cable 2-3 has been determined by the corresponding sliding of the adjusting rod RE, the position of the lock nut TA, shown in Figure 4 and attained by rotation thereof, causes the screw thread of the retaining fingers GR and the external screw thread 1 of the adjusting rod RE to be firmly locked together, so that the longitudinal sliding of said adjusting rod RE is prevented. Figure 3 shows how the the recesses 7 and the projections 20, disposed on the main body CP and the lock nut TA respectively, become mutually engaged to prevent the lock nut TA from extemporaneously coming out of or changing the locking position described. Figures 5, 7 and 9 show the terminal of the invention in which the length of the sheathed cable 2-3 is adjusted automatically by the action of the spring 10 housed inside the main body CP. Figure 9 shows the state in which the terminal of the invention is supplied for use. Under these conditions of supply, the spring 10 is compressed owing to the position occupied by the adjusting rod RE and the length of the sheathed cable 2-3 is at its shortest. The position of the adjusting rod RE is firmly fixed, since the screw threads 1 and 17 on the adjusting rod RE and the retaining fingers GR, respectively, are locked together by the action of the longitudinal tightening projections 19 formed on the inside of the lock nut TA since the latter is in the position shown in Figure 9. In this position of the lock nut TA, the recesses 7 and projections 20, disposed on the main body CP and on the lock nut TA, respectively, are in mutual engagement and prevent the said lock nut TA from coming out of or changing the locking position described. Once the terminal of the invention has been firmly attached to a fixed point by way of the mechanical means AN formed on the main body CP and the ends of the cable 3 and sheath 2 are appropiately attached, rotation of the lock nut TA causes release of the adjusting rod RE which is urged by the spring 10 to slide longitudinally to the point in which the length of the sheathed cable 2-3 is appropriate for the particular application. Once the length of the sheathed cable 2-3 has been set automatically, the position of the adjusting rod RE is firmly fixed by a further rotation of the lock nut TA which causes the longitudinal tightening projections 19 thereof to engage the retaining fingers GR, whereby the screw threads 1 and 17 of the adjusting rod RE and the retaining fingers GR, respectively, will be locked together, thereby preventing the position of the adjusting rod RE and, consequently, the adjusted length of the sheathed cable 2-3 from varying. The mutual engagement of the recesses 7 and the projections 20, disposed on the main body CP and on the lock nut TA, in turn prevents the lock nut TA from coming out of or changing the locked position described. Figure 5 shows the position occupied by the adjusting rod RE urged by the spring 10 when the latter is released and in which the length of the sheathed cable 2-3 is at its longest. Fixation in this position is carried out as described above. The embodiment described is obviously not limitative of the application of the terminal of the invention to control devices and it may be modified in any way not affecting the essential structure thereof which is necessary to adapt it to the needs of each particular application.

Claims: An adjustable cable sheath terminal constituted by an essentially cylindrical hollow main body (CP) provided with mechanical means (AN) for anchorage to a fixed point; by an adjusting rod (RE) having an external screw thread (1) and which, fixedly attached at one of the ends thereof to the sheath (2) of the cable (3) whose length is to be adjusted may slide over a sufficient distance inside said main body (CP); and by retaining fingers (GR) which may firmly retain the said adjusting rod (RE) in the desired position, characterized in that it is further constituted by a lock nut (TA) which engages the retaining fingers (GR), said lock nut (TA) being provided on the outer surface of the main body (CP) and being positioned to cover radial through holes (5) formed in said main body (CP), the lock nut (TA) being provided in the interior thereof with tightening projections (19) for pressing against the retaining fingers (GR), said retaining fingers (GR) being housed in said radial through holes (5) of said main body (CP). The adjustable cable sheath terminal of claim 1, characterized in that said radial through holes (5) are disposed on a single plane perpendicular to the longitudinal axis of the main body (CP), for adjustably housing the retaining fingers (GR) which are of the same number as the radial holes. The adjustable cable sheath terminal according to one of the claims 1 or 2, characterized in that the outer surface of the main body (CP) is formed with longitudinal projections (6) for correctly positioning the lock nut (TA) relative to the adjusting rod (RE) and said retaining fingers (GR) and with a sufficient number of appropriately dimensioned recesses (7) for setting the position of the said lock nut (TA) preventing it from extemporaneously coming out of or changing its locked position. The adjustable cable sheath terminal according to one of the claims 1 to 3, characterized in that the through hole (8) of the main body (CP) through which the adjusting rod (RE) attached to the sheath (2) of the cable (3) can slide over a sufficient distance, is provided with two portions (8a, 8b) of different diameters which may have a different length, on one of which (8a) the adjusting rod (RE) can snugly slide, while the other portion (8b), which is of larger diameter, comprises lips (9) limiting the maximum movement of the adjusting rod (RE) and preventing it from coming out of the main body (CP). The adjustable cable sheath terminal according to one of the claims 1 to 4, characterized in that the position of the adjusting rod (RE), which is fixedly attached at one end thereof to the sheath (2) of the cable (3) inside the main body (CP) and which precisely caters for the adjustment of the length of the sheathed cable (2, 3), is controlled manually or automatically by way of a spring (10) which is incorporated inside said main body (CP). The adjustable cable sheath terminal according to one of the claims 1 to 5, characterized in that the larger diameter portion (8b) of the main body (CP) through hole (8), through which the adjusting rod (RE) attached to the sheath (2) of the cable (3) can slide, is dimensioned such that it can conveniently house a spring (10) which, under compression, automatically adjusts the sheathed cable (2, 3) length. The adjustable cable sheath terminal according to claim 6, characterized in that the spring (10) is preferably disposed coaxially relative to the adjusting rod (RE) and presses at one end thereof against the flat surface (8p) defining the change of section (8a, 8b) of the main body (CP) through hole (8), said flat surface (8p) being perpendicular to the longitudinal axis of the through hole (8) and, at the other end thereof, presses against the adjusting rod (RE). The adjustable cable sheath terminal according to one of the claims 1 to 7, characterized in that the adjusting rod (RE), which is provided with an external screw thread (1) extending over a sufficient distance and is fixedly attached at one end thereof to the sheath (2) of the cable (3), is provided with a longitudinal through hole (11) through which the portion of sheathless cable (3) crossing through the main body (CP) may conveniently slide, the said end having a preferably annular projection (12) which coacts with the lips (9) formed inside the main body (CP). The adjustable cable sheath terminal according to claim 1, characterized in that the retaining fingers (GR) for the adjusting rod (RE) are essentially parallelepipedic, two opposing surfaces thereof being slightly curved, one of which is provided with a screw thread (17) of the same pitch as the screw thread (1) formed on the outer surface of the adjusting rod (RE), the retaining fingers (GR) also being provided with ejector springs, such as corresponding resilient projections (18) which permanently urge said fingers (GR) radially outwardly, to establish the appropriate rest, i.e. released position thereof, in the radial through holes (5) formed in the main body (CP). The adjustable cable sheath terminal of claim 1 or 9, characterized in that the retaining fingers (GR) are attached to a concentric open perimeter ring of resilient material, acting as ejector springs in replacement of the said resilient extensions (18). The adjustable cable sheath terminal according to one of the claims 1 to 10, characterized in that the longitudinal tightening projections (19) of the lock nut (TA) are provided for pressing, after an appropriate rotation of the lock nut (TA), against the said retaining fingers (GR) and overcoming the permanent action of the ejector springs, to which end the number and position thereof are the same as the number and position of the radial through holes (5) formed in the main body (CP) in which said retaining fingers (GR) are located, there also being in the interior of said lock nut positioning projections (20), the number and position of which are also the same as the number and position of the recesses (7) formed on the outer surface of the main body (CP) for setting the position of the lock nut (TA) in the locking or retaining position of the adjusting rod (RE). The adjustable cable sheath terminal according to one of the claims 1 to 11, characterized in that the lock nut (TA) is provided on the outer surface thereof with a knurled portion or a number of alternating recesses (21) of appropriate dimensions which are for facilitating the operations of setting the length of the sheathed cable (2, 3) for the operative. The adjustable cable sheath terminal according to one of the claims 1 to 12, characterized in that the end of the adjusting rod (RE) opposite to the one fixedly attached to the sheath (2) of the cable (3) is optionally provided with a tubular guide (15) through which the sheathless portion of cable (3) slides.

Inventors: ROCA CABESTANY AGUSTIN, ROCA CABESTANY, AGUSTIN
Applicants: FICO CABLES SA, FICO-CABLES, S.A.
Application year: 1990
Main classification: F16C1
IPC codes: F16C1