GB1592827A

GB1592827A - Self gripping clamp with interchangeable liners

Info

Publication number: GB1592827A
Application number: GB10004/78A
Authority: GB
Original assignee: INNOCENTE RIGANTI OFFICINE MECCANICHE SpA
Current assignee: INNOCENTE RIGANTI OFFICINE MECCANICHE SpA
Priority date: 1977-03-29
Filing date: 1978-03-14
Publication date: 1981-07-08
Also published as: BE865236A; AR215170A1; FR2386168B1; IT1085343B; ATA197678A; JPS53120043A; NL7803222A; ES243486U; BR7801740A; AT366209B; DE2811271A1; FR2386168A1; LU79334A1; GR64105B; AU522353B2; ES243486Y; IN149594B; AU3465378A; ZA781762B

Description

(54) A SELF GRIPPING CLAMP WITH INTERCHANGEABLE LINERS (71) We, INNOCENTE RIGANTI OFFICINE MECCANICHE S.P.A. an Italian Company of Via Vittorio Veneto, 1 Solbiate Arno Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a self gripping clamp for use in gripping metal cables, particularly in the stringing work for conductors of overhead electric lines.

Self gripping clamps are used when cables are to be gripped and pulled temporarily. It is essential that the cables shall not become detached from the slip in the clamps. Such clamps are called "self gripping" since the clamp jaws are pressed onto the cables by the tension on the clamp when the clamp itself is pulled, either by hand or by winch through its handle, or by the tensioned cable itself.

With known self gripping clamps the problem arises that each single clamp is only able to clamp cables within a very small diameter range and that clamps of different material have to be used depending on the material of the cable to be gripped.

Therefore, it will be appreciated that, to be in a position to grip cables of different materials and of a wide diameter range as presently available, a large range of clamps must be available for use.

According to the present invention there is provided a self gripping clamp for metal cables together with a plurality of pairs of liners forming a set of liners therefor, each pair of liners in the set being adapted for attachment to the clamp to grip a cable therebetween and each pair of liners in the set being different from all the other pairs of liners in the set in regard to size and/or shape and/or composition of material.

Consequently, the same clamp can be used under different working conditions; it will only be necessary to house in the jaws, that liner couple which is suitable for a certain application depending on the cable size and material. Particularly, the liner pairs of the invention comprise two liners, each to be fitted in a corresponding jaw groove of the clamp. Each liner comprises a working face which will receive the conductor section to be clamped and another face which is housed and fixed in the jaw groove of the clamp. The latter face will be called in the following description as the "housing face". Such housing face is so shaped as to form a reliable attachment with the jaw groove and is provided with at least one projection, preferably two projections with threaded holes that allow the liner to be secured to the jaw so as to prevent the liner from slipping and moving on operation.

Each liner of the liner pairs a plurality of which form the set to be fitted in the clamp have, therefore, an identical face for housing within the clamp jaws.

The other face of each liner is of such a shape as to clamp a small range of conductor diameters.

It will be appreciated that, by using the invented clamp one clamp only, supplied with a set of liner pairs, allows the clamping of a large range of conductor diameters. A typical range is 7.5 mm. The advantage obtained by interchangeable liner pairs will be realized when this clamp is compared with known clamps which are able to clamp cables of diameters within a range of 1.5 mm only.

In addition, the invented clamp allows the fitting of liners which are different in material which considerably increases the range of use of a single clamp. Indeed, it is known that in stringing work in overhead electric lines, the cables may be of steel, copper, aluminium or aluminium alloy. It is advisable to clamp such cables by liners of bronze or steel when the cables are of steel and by liners of aluminium alloy when the cables are of copper or aluminium alloy.

One embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing in which: Figure 1 is a side elevation of a self gripping clamp and a liner pair according to the invention, Figure 2 is a perspective view of the two liners, out of the clamp, but in the same relative position in which they are when housed in the clamp jaws; Figure 3 is a cross section through 1-I of Figure 1, of the clamp with a liner pair housed therein; Figure 4 is a cross section, through Il-Il of Figure 1, of the clamp with a liner pair housed therein; and Figure 5 is a perspective view of a single liner having a cross section which is substantially rectangular.

The clamp shown in Figure 1 is in the position in which the jaws 2 and 2' are open so as to allow a cable (not shown) to lie in the lower liner 11'. Once the cable is placed in the liner 11', the handle 3 is pulled, the pin 5, connecting the handle with lever 7, moves along slot 8 and part 4, pulled by lever 7, turns about pin 15 under the pressure of spring 20 pivoting about pin 21 and abuting part 4. Jaw 2 is subject to rotation about pin 19 and to translation movement being guided by pin 10 sliding in slot 9. The jaw 2 moves towards and arrives just opposite jaw 2' so that upper liner 11 engages the cable which, consequently, is pressed between the two liners 11 and 11'.

With increased pulling force applied to handle, 3, the pressure of two jaws on the cable increases too.

The grooves ofjaws 2 and 2' are so shaped as to receive the housing face of liners 11 and 11'. Jaws 2 and 2' are further provided with two truncated conical recesses and two holes in register with two truncated conical projections 16-16' and 18-18', having theaded holes, so that liners 11 and 11' are respectively housed and fixed in the grooves of jaws 2 and 2' by screws 12-12' and 1414'.

The liners 11 and 11' are so shaped as to allow the clamp to clamp a small range of diameters. In the jaws 2 and 2' pairs of other liners in the set may be housed and attached, which liners will be identical with liners 11 and 11' as far as the housing surfaces are concerned, but the other liners will differ in regard to size and/or shape and/or composition of material.

As shown in Figure 4 the longitudinal edges of the liner will be extended by a different amount along the circular profile so that, when in the open position, the inner longitudinal edges will be spaced by a but the outer longitudinal edges will be spaced by A greater than a in order to make it easier to insert a cable within the jaws provided with the liners. Thus, in this embodiment, the pair of liners are, in lateral cross-section, semi-circular and have first opposed longitudinal edges and second opposed longitudinal edges, the first said edges being spaced a greater distance than the second said edges when the liners are attached to the clamp.

The construction described above may be modified without departing from the scope of the invention as defined in the appended claims, for example, the liners may be fixed to the clamp jaws without screws, but by means of groove-and-tongue joints, namely by projections in the liners fitting in corresponding recesses in the jaws which projections further slide into further jaw recesses in the direction by which the liners would move when the clamp is pulled.

Also it will be appreciated that to the self gripping clamp may be attached liners of any lateral cross section, for instance, square, rectangular, triangular or semicircular in order to clamp cables of corresponding shape.

WHAT WE CLAIM IS:- 1. A self gripping clamp for metal cables together with a plurality of pairs of liners forming a set of liners therefor, each pair of liners in the set being adapted for attachment to the clamp to grip a cable therebetween and each pair of liners in the set being different from all the other pairs of liners in the set in regard to size and/or shape and/or composition of material.

2. A self gripping clamp and a set of liners therefor as claimed in Claim I, in which the liners are of aluminium or bronze or steel.

3. A self gripping clamp and a set of liners therefor as claimed in either Claim 1 or Claim 2, in which the liners are in lateral cross-section, semicircular or triangular or rectangular.

4. A self gripping clamp and a set of liners therefor as claimed in any one of the preceding claims, in which each liner is provided with a projection adapted to enter a complementary recess in the clamp, the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. with reference to the accompanying drawing in which: Figure 1 is a side elevation of a self gripping clamp and a liner pair according to the invention, Figure 2 is a perspective view of the two liners, out of the clamp, but in the same relative position in which they are when housed in the clamp jaws; Figure 3 is a cross section through 1-I of Figure 1, of the clamp with a liner pair housed therein; Figure 4 is a cross section, through Il-Il of Figure 1, of the clamp with a liner pair housed therein; and Figure 5 is a perspective view of a single liner having a cross section which is substantially rectangular. The clamp shown in Figure 1 is in the position in which the jaws 2 and 2' are open so as to allow a cable (not shown) to lie in the lower liner 11'. Once the cable is placed in the liner 11', the handle 3 is pulled, the pin 5, connecting the handle with lever 7, moves along slot 8 and part 4, pulled by lever 7, turns about pin 15 under the pressure of spring 20 pivoting about pin 21 and abuting part 4. Jaw 2 is subject to rotation about pin 19 and to translation movement being guided by pin 10 sliding in slot 9. The jaw 2 moves towards and arrives just opposite jaw 2' so that upper liner 11 engages the cable which, consequently, is pressed between the two liners 11 and 11'. With increased pulling force applied to handle, 3, the pressure of two jaws on the cable increases too. The grooves ofjaws 2 and 2' are so shaped as to receive the housing face of liners 11 and 11'. Jaws 2 and 2' are further provided with two truncated conical recesses and two holes in register with two truncated conical projections 16-16' and 18-18', having theaded holes, so that liners 11 and 11' are respectively housed and fixed in the grooves of jaws 2 and 2' by screws 12-12' and 1414'. The liners 11 and 11' are so shaped as to allow the clamp to clamp a small range of diameters. In the jaws 2 and 2' pairs of other liners in the set may be housed and attached, which liners will be identical with liners 11 and 11' as far as the housing surfaces are concerned, but the other liners will differ in regard to size and/or shape and/or composition of material. As shown in Figure 4 the longitudinal edges of the liner will be extended by a different amount along the circular profile so that, when in the open position, the inner longitudinal edges will be spaced by a but the outer longitudinal edges will be spaced by A greater than a in order to make it easier to insert a cable within the jaws provided with the liners. Thus, in this embodiment, the pair of liners are, in lateral cross-section, semi-circular and have first opposed longitudinal edges and second opposed longitudinal edges, the first said edges being spaced a greater distance than the second said edges when the liners are attached to the clamp. The construction described above may be modified without departing from the scope of the invention as defined in the appended claims, for example, the liners may be fixed to the clamp jaws without screws, but by means of groove-and-tongue joints, namely by projections in the liners fitting in corresponding recesses in the jaws which projections further slide into further jaw recesses in the direction by which the liners would move when the clamp is pulled. Also it will be appreciated that to the self gripping clamp may be attached liners of any lateral cross section, for instance, square, rectangular, triangular or semicircular in order to clamp cables of corresponding shape. WHAT WE CLAIM IS:-

1. A self gripping clamp for metal cables together with a plurality of pairs of liners forming a set of liners therefor, each pair of liners in the set being adapted for attachment to the clamp to grip a cable therebetween and each pair of liners in the set being different from all the other pairs of liners in the set in regard to size and/or shape and/or composition of material.

projection having a threaded hole therein which receives a screw for attaching the liner to the clamp.

5. A self gripping clamp and a set of liners therefor as claimed in Claim 1 or Claim 2, in which a pair of liners in the set are, in lateral cross-section, semicircular and have first opposed longitudinal edges and second opposed longitudinal edges, the first said edges being spaced a greater distance than the second said edges when the liners are attached to the clamp.

6. A self gripping clamp and a set of liners therefor substantially as herein described with reference to Figs. 1, 3 and 4 of the accompanying drawing.