WO1998000644A1

WO1998000644A1 - Clamp and clamping tool therefor

Info

Publication number: WO1998000644A1
Application number: PCT/SE1997/001014
Authority: WO
Inventors: Staffan Svensson
Original assignee: Henrysson, Per; Henrysson, Christer
Priority date: 1996-06-28
Filing date: 1997-06-11
Publication date: 1998-01-08
Also published as: AU3365497A; SE506840C2; SE9602599L; SE9602599D0

Abstract

A clamping tool for connecting elongated members (10) comprises a housing (1), a magazine for the clamps and a piston. In its lower part, the piston has two fixed, projecting lugs (9) for fitting and closing the clamps around the elongated members (10), and the piston is movable from an upper position to a lower position. A guide rod (13) is arranged in a recess in the piston and is movable relative to the piston in the direction of movement of the latter from and to a limit position. The lower part of the guide rod (13) is adapted to detachably hold a central part of the clamp during the movement of the piston from the upper to the lower position. A clamp intended for the clamping tool has two curved legs (31), which are connected by means of a central guide portion (32) and which have coacting locking means in their free ends. The legs (31) are flexible relative to the guide portion (32) from an open to a closed connecting position. At least one section of each leg (31) adjacent to the guide portion (32) is rigid and has an outer actuating surface for receiving a force, which closes the clamp.

Description

CLAMP AND CLAMPING TOOL THEREFOR

The present invention relates to a clamp and a device for installing the same, more specifically a clamp and a clamping tool for connecting elongated members, such as reinforcing bars, by means of the clamp. The device and the associated clamp can be used for connecting any two elongated members, which cross or touch, but in order to simplify the description, the present invention will be described on the basis of clamps and clamping tools intended for lashing of reinforcing bars.

Among prior art there are a number of different clamping tools with associated means for connecting elongated members .

A method and a device for attaching a fastening means around two members, such as two reinforcing bars which are to be joined, are described in the international patent application with publication number WO 92/21839. The device according to this publication comprises a housing, a magazine for clamps, a piston and a pair of jaws, each of which is pivotably mounted around a pivot shaft. The piston is adapted to move the pivot shafts of the jaws from a first position for receiving a fastening means from the magazine to a second position for attaching the fastening means around the reinforcing bars. In this second position, the upper parts of the jaws are acted upon by the piston, which is adapted to press the upper ends of the jaws away from each other. Side openings which are arranged in the housing enable the jaws to pivot around their respective pivot shafts. This pivot motion will thus make the fastening means close around the reinforcing bars. When the piston is withdrawn to the first position, the jaws are forced back into the housing by springs, which are arranged in the side openings in the housing. The fastening means according to said publication consists of a thread, which has a triangular shape with one open side for receiving the reinforcing bars. Further, the ends of the fastening means are equipped with hooks for keeping the fastening means in a closed position around the reinforcing bars .

In the prior-art device described above, many different parts have to coact in order to fix the fastening means around the reinforcing bars . The pivot motion of the jaws must correlate with their vertical movement between the upper position for receiving a fastening means and the lower position for fitting the fastening means around the reinforcing bars . This makes the device complicated and error-prone. One object of the present invention is to provide a simple clamping tool with few moving parts .

Another object is to provide a clamp for use in the clamping tool according to the present invention.

Other objects, features and advantages of the pre- sent invention can be seen from the description below. These objects are achieved by a clamp and a device according to claim 1 and claim 9. A cartridge composed of such clamps is set forth in claim 8. Particularly preferred embodiments are set forth in the subclaims. In short, the present invention relates to a clamping tool for connecting elongated members. The tool comprises a housing, a magazine for the clamps and a piston. In its lower part, the piston has two fixed, projecting lugs for fitting and closing the clamps around the elon- gated members, and the piston is movable from an upper position to a lower position. A guide rod is arranged in a recess in the piston and is movable relative to the piston in the direction of movement of the latter from and to a limit position. The lower part of the guide rod is adapted to detachably hold a central part of the clamp during the movement of the piston from the upper to the lower position. Moreover, the present invention relates to a clamp. This clamp has two curved legs, which are joined by means of a central guide portion and have coacting locking means in their free ends . The legs are flexible relative to the guide portion from an open to a closed connection position. At least one section of each leg adjacent to the guide portion is rigid and has an outer actuating surface for receiving a force, which closes the clamp.

The advantage of the present invention is that the clamping tool has few moving parts and is thus easy and inexpensive to manufacture.

Preferred embodiments of the invention will be described below with reference to the accompanying drawings. These shall not be considered to limit the scope of the present invention.

Fig. 1 is a side view of a preferred embodiment of the device according to the present invention.

Fig. 2 is a plan view of the device in Fig. 1.

Fig. 3 is a front view of the piston in the device in Figs 1 and 2.

Fig. 4 is a front view of the guide rod in the device in Figs 1 and 2.

Fig. 5 shows a section along the line V-V in Fig. 2.

Fig. 6 shows the same section as in Fig. 5, where a clamp is being transferred to a lower position for the piston to fit and close the clamp around two elongated members .

Fig. 7 shows a section along the line VII-VII in Fig. 6, where the projecting lugs of the piston have forced the clamp to close around the elongated members.

Fig. 8 is a front view of a preferred embodiment of a clamp according to the present invention.

Fig. 9 is a side view of the clamp in Fig. 8 seen from the line XI-XI. Fig. 10 shows a section along the line X-X in Fig. 8. Fig. 11 is a detail drawing of a locking means in the clamp according to Fig. 8 in the locked position.

Fig. 12 is a side view of a cartridge of the clamps according to Fig . 8. The device according to the present invention shown in Figs 1-7 has a housing 1, a magazine 2 for clamps and a piston 3. The housing 1 has an upper opening 4 for receiving the piston, a side opening 5 for receiving clamps from the magazine 2, and a lower opening 6 for delivering the clamps. The upper opening 4 and the lower opening 6 are connected by means of a through channel which is formed by the housing 1 and has the same cross- section as these openings 4, 6 and the piston 3 have. Further, the magazine 2 has a feeding device 7 for feed- ing the clamps into the housing 1 through the side opening 5.

In its upper end, the piston 3 has a handle 8 and in its lower end it has two fixed, projecting lugs 9 for fitting and closing the clamps around two elongated mem- bers 10, for example reinforcing bars. Moreover, the piston 3 has a recess 11 with protrusions 12 and is movable from an upper position, shown in Figs 1 and 2, to a lower position, shown in Fig. 7, relative to the housing 1. A guide rod 13 is arranged in the recess 11 and between the protrusions 12, which rod is movable relative to the piston 3 in the direction of movement of the latter from and to a limit position, which is shown in Fig. 2.

The guide rod 13 has an enlarged upper part 14 and, by engaging with the enlarged upper part 14 of the guide rod 13, the protrusions 12 are adapted to determine the limit position of the guide rod 13. Further, the lower part of the guide rod 13 has a recess 15 for receiving a central part of the clamp, the recess 15 being adapted to detachably hold this central part of the clamp during the movement of the clamp 3 from the upper to the lower position. Moreover, the device in Figs 1-7 has a feeding device 7 for feeding clamps to the housing 1. More specifically, the feeding device 7 consists of an arm 16 with an shaft 17, which is rotatably mounted on the side of the housing 1 adjacent to the magazine 2, so that the arm 16 is pivotable in a plane, which is extended by the longitudinal axis of the housing 1 and the longitudinal axis of the magazine 2. A spring 18 presses the arm 16 against the magazine side of the housing 1 and, in this connec- tion, two guide lugs 19 on the outer end of the arm 16 project down into the channel of the housing 1 between the openings 4 and 6 and in front of the lower end of the piston 3, when the latter is in its upper position. Further, a driver 20 is attached to the outer end of the arm 16 in such a way that it strives to press a hook 21 on its end next to the housing 1 into engagement with a clamp in the magazine 2.

Moreover, the piston 3 is arranged in a spring-biased manner relative to the housing 1 by being mounted and guided in the housing 1 by means of two rods 22, which are fixedly connected to the handle 8 and constitute a guide for two compression springs 23, which press the piston 3 away from the housing 1 to the upper position.

The clamp 30 shown in Figs 8-12, which preferably is made of plastic, has two curved legs 31 connected to each other. The legs 31 are connected by means of a central guide portion 32 in an open starting position, shown in Fig 8, and are flexible relative to the guide portion 32 to a closed connecting position, shown in Figs 7 and 11. Each leg 31 has at least one section adjacent to the guide portion 32, which section is rigid as a result of the I-beam-shaped cross-section, as seen in Fig. 10, and has an exterior actuating surface 33 for receiving a force, which closes the clamp 30. The central guide portion 32 has a guide pin 34. A breakaway binding 35 is arranged between the guide pin 34 and each leg 31, which binding breaks when the clamp 30 is subjected to the closing force.

The legs 31 in the clamp 30 according to the present invention have coacting locking means 36, 37 in their free ends. These locking means 36, 37 comprise a sleeve part 36 and a pin part 37, which have coacting locking members in the form of lock-engagement surfaces, which are formed as sawtooth surfaces 38. The lock-engagement surface 38 in the sleeve part 36 is subjected to spring- bias, and prior to the insertion of the pin part 37, the opening of the sleeve part 36 is covered by a wedge 39, which is arranged in a spring-biased manner in the wall of the sleeve part 36 opposite the lock-engagement surface 38 of the sleeve part 36 in order to be folded into the sleeve part 36 upon insertion of the pin part 37 and to act upon the pin part 37 with a force directed at the lock-engagement surface 38 of the sleeve part 36.

Fig. 12 shows a cartridge 40 consisting of a plurality of clamps 30 according to Figs 8-11. More specifi- cally, it consists of a stack of clamps 30, which are held together by fuse or weld joints 41 in mutual contact surfaces.

As can be seen from Fig. 2, the magazine 2 is cylindrical with a cross-sectional shape which conforms to the shape of the clamps 30 and the cartridge 40. For guiding the cartridge 40 in the magazine 2, the latter has on its inside two guide bars 42, which hold the cartridge 40 in place outside the housing 1. The cartridge 40 is also guided in the magazine 2 by the housing 1 exhibiting an open slit 43, which is fixedly arranged in a position inside the magazine 2 such that it partially surrounds the guide pins 34 of the clamps 30 located closest to the housing 1 in the cartridge 40.

When the clamping tool according to the invention is in use, a cartridge 40 is fed into the magazine 2, so that the bottom clamp 30 in the cartridge 40 is located inside the housing 1 and, more specifically, inside its channel and below or in front of the lower or free end of the piston 3. When the piston 3 is inserted into the housing 1 against the action of the springs 23, first, the two projecting lugs 9 on the piston 3 will press the clamp 30 which is located inside the housing 1 free from the cartridge 40 by contacting the rigid portions of the clamp 30 adjacent to the guide portion 34, which will engage with the recess 15 in the guide rod 13, so that the clamp 30 pulled away from the cartridge 40 is held in place relative to the piston 3.

When the clamp 30 which has been pulled away has almost been moved past the cartridge 40, as shown in Fig. 6, guide surfaces 44 in the protrusions 12 will swing the arm 16 out from the housing 1 by engagement with the lugs 19 and against the action of the spring 18. The hook 21 is thereby moved up along the side of the cartridge 40 for engagement with the now bottom clamp 30 in the cartridge 40.

In connection with the continued movement of the piston 3 through the housing 1 , the central guide portion 32 of the clamp 30 contacts one of the elongated members 10 which are to be connected by means of the clamp 30. Thereby, the continued movement of the guide rod 13 is stopped, so that during the continued movement of the piston 3 it is moved relative to the piston 3 and from its limit position, while, however, the engagement between the recess 15 and the guide rod 34 remains. During this continued movement of the piston 3, the lugs 9 force the legs of the clamp 30 to pivot downwards from the guide portion 32, whereby, first, the two bindings 35 break and, subsequently, the pin part 37, while pushing aside the wedge 39, penetrates into the sleeve part 36, and engagement is achieved between the lock-engagement surfaces 38 of the pin part 37 and the sleeve part 36. When the connection has been made, i.e. the pin part 37 is inserted as far into the sleeve part 36 as the members 10 will allow, the piston 3 can be moved back from this its lower position to its upper position or the starting position. This takes place automatically when the pressure on the piston 3 is lightened as a result of the action of the springs 23. More specifically, the pis- ton 3 will be moved back up until the guide rod 13 with its enlarged upper part 14 engages with the protrusions 12, whereby the guide rod is returned to its limit position and subsequently joins the piston 3 in its continued return movement to the upper position. When the guide surfaces 44 pass the lugs 19, the arm 16 will be moved back towards the housing 1 by the spring 18, the hook 21 on the driver 20 moving the whole cartridge 40 a distance equivalent to the thickness of a clamp 30 into the side opening 5, i.e. so that the clamp 30 located closest to the housing in the cartridge 40 is inside the channel in the housing 1.

With that, the clamping tool is ready for the application of another clamp.

Thus, the present invention provides a clamp and a clamping tool therefor, the clamping tool having few moving parts and being accordingly easy and inexpensive to manufactur .

The described preferred embodiment of the clamp and the clamping tool should not be considered to limit the scope of the present invention, rather the scope of the invention should be determined by the appended independent claims.

Claims

1. A clamp for connecting elongated members, which clamp has two connected, curved legs (31), which in their free ends have coacting locking means (36, 37), c h a r a c t e r i s e d in that the legs (31) are connected by means of a central guide portion ( 32 ) in an open starting position and are flexible relative to the guide portion to a closed connecting position, that at least one section of each leg (31) adjacent to the guide portion ( 32 ) is rigid and has an exterior actuating surface ( 33 ) for receiving a force closing the clamp.

2. A clamp according to claim 1, c h a r a c t e r i s e d in that the guide portion ( 32 ) has a guide pin (34).

3. A clamp according to claim 1 or 2, c h a r a c - t e r i s e d in that the coacting locking means (36, 37) comprise a sleeve part (36) and a pin part (37), these having coacting locking members (38).

4. A clamp according to claim 3, c h a r a c t e r i se in that the locking members (38) are formed as lock-engagement surfaces, the lock-engagement surface of the sleeve part (36) being arranged in a spring-biased manner.

5. A clamp according to claim 3 or 4, c h a r a c t e r i s e d in that, prior to the insertion of the pin part (37), the opening of the sleeve part (36) is covered by a wedge (39), which is arranged in a spring-biased manner in the wall of the sleeve part opposite the lock- engagement surface (38) of the sleeve part in order to be folded into the sleeve part upon insertion of the pin part and to act upon the pin part with a force directed at the lock-engagement surface of the sleeve part.

6. A clamp according to claim 4 or 5, ch a r a c t e r i s e d in that the lock-engagement surfaces (38) comprise sawtooth surfaces .

7. A clamp according to any one of the preceding claims, c h a r a c t e r i s ed in that a breakaway binding (35) is arranged between the guide pin (34) and each leg (31), which binding is adapted to break when the clamp is subjected to a closing force.

8. A cartridge, c h a r a c t e r i s e d in that it consists of a stack of clamps (30) according to any one of claims 1-7.

9. A device for connecting elongated members (10) by means of clamps (30) according to any one of claims 1-7, which device comprises a housing ( 1 ) , a magazine ( 2 ) for the clamps and a piston (3), the housing having an upper opening (4) for receiving the piston, a side opening (5) for receiving the clamps from the magazine and a lower opening ( 6 ) for delivering the clamps , the magazine having a device (7) for feeding the clamps to the housing, the piston ( 3 ) in its upper part having a handle ( 8 ) and in its lower part having a device for fitting and closing the clamps around the elongated members, and the piston (3) being movable from an upper position to a lower position, c h a r a c t e r i s e d in that the device for fitting and closing the clamps around the elongated members comprises two fixed, protruding lugs ( 9 ) in the lower end of the piston for transmission of force to a rigid section of a clamp, that a guide rod (13) is arranged in a recess (11) in the piston ( 3 ) and is movable relative to the piston in the direction of movement of the latter from and to a limit position, that the lower part (15) of the guide rod (13) is adapted to detachably hold the central guide portion (32) of a clamp during the movement of the piston from the upper to the lower position and to be displaced from its limit position in connection with the closing of the clamp by the piston, and that, in connection with its return to the upper position, the piston is adapted to bring the guide rod back to its limit position.

10. A device according to claim 9, c h a r a c t e r i s e d in that the guide rod ( 13 ) has an enlarged upper part (14), and that the recess (11) in the piston (3) has protrusions (12), which, by engaging with the enlarged upper part of the guide rod, are adapted to determine the limit position of the guide rod.

11. A device according to claim 9 or 10, c h a r a c t e r i s e d in that the lower part of the guide rod (13) has a recess (15) for detachable reception of the central guide portion (34) of the clamp (30) and guiding thereof.