GB2325686A

GB2325686A - A screw clamp for rail joints

Info

Publication number: GB2325686A
Application number: GB9801886A
Authority: GB
Inventors: Bruno Strobl
Original assignee: Georg Robel GmbH and Co
Current assignee: Georg Robel GmbH and Co
Priority date: 1997-01-28
Filing date: 1998-01-28
Publication date: 1998-12-02
Anticipated expiration: 2018-01-28
Also published as: GB9801886D0; GB2325686B; FR2760246B1; FR2760246A1; AT409770B; ATA12498A; DE29701396U1

Abstract

A screw clamp 1 for temporarily connecting two successive rails 4 of a track with the aid of fish-plates 8, particularly for making a suspended butt joint, consists of a respective clamping piece 2 on either side of the corresponding rail 4 and at least one tightening screw 3 connecting the two clamping pieces. The tightening screws each have a nut 9 and a safety flap 10 associated therewith, the safety flap being fastened to the clamping piece 2 and adjustable with respect thereto and serving for form-fittingly safeguarding the nut 9 against rotation. The safety flap 10 is displaceably mounted in a guide 12 of the clamping piece 2 for spacing the safety flap 10 from the tightening screw 3. A blocking device 16 is provided for automatically precluding a pivoting movement of the safety flap 10 with distancing from the tightening screw 3 as soon as the safety flap 10 reaches the lowermost displacement position.

Description

1 A SCREW CLAMP 2325686 The invention relates to a screw clamp for

temporarily connecting two successive rails of a track, preferably with the aid of fish-plates, particularly for making a suspended butt joint, the rails each comprising a rail head having a running surface, a rail web extending perpendicularly to the running surface, and a rail base extending parallel to the running surface, the screw clamp consisting of a respective clamping piece on either side of the corresponding rail and at least one tightening screw connecting the two clamping pieces and having a respective nut and a safety flap associated therewith, the safety flap being fastened to the clamping piece and adjustable with respect thereto and serving for form-fittingly safeguarding the nut against rotation.

A screw clamp for temporarily connecting two successive rails of a track is already known from DE 29 52 734 C2. Said screw clamp is composed of two clamping pieces, lying opposite one another in the transverse direction of the track and designed to be screwed together, by means of which fish-plates are pressed onto two butt-jointed rail ends. Beyond that, it is also known to provide a so-called drop flap.for safeguarding against rotation of a nut of a tightening screw connecting the two clamping pieces. However, said drop flap, vertically displaceably mounted in a recess of the clamping piece, has the disadvantage of tending to bind, thus often making it more difficult to loosen the nut or to properly safeguard against rotation.

Furthermore, a like screw clamp is known from DE 93 02 995 Ul, with a safety flap for form-fittingly safeguarding the nut against rotation being mounted to the clamping piece f or pivoting about an axis extending in the longitudinal direction of the rail. Safety flaps of this kind, however, may come loose 2 from the nut as a result of vibrations and thereby compromise the safeguarding against rotation.

It is the object of the present invention to equip a screw clamp of the type described at the beginning with a safeguard against rotation which is reliably effective also in the case of strong vibrational influences.

This object is achieved with a screw clamp of the specified kind in that the safety flap is displaceably mounted in a guide of the clamping piece for spacing the safety flap from the tightening screw, and a blocking device is provided for automatically precluding a pivoting movement of the safety flap with distancing from the tightening screw as soon as the safety flap reaches the lowermost displacement position.

Such a blocking device ensures a reliable safe-guarding against rotation by mechanically blocking a possible liftingoff of the safety flap from the nut due to vibrations or shaking. The blocking can be cancelled simply and quickly by lifting up the safety flap in the guide to distance it from the nut. In doing so, it is of particular advantage that no additional parts of any kind nor adjusting operations are required for changing from the blocking position to pivoting.

Additional advantageous embodiments of the invention are explained in the sub-claims and the drawings.

The invention is described in detail below with reference to embodiments represented in the drawing, in which Fig. 1 shows a screw clamp formed by two clamping pieces, with one clamping piece, the rail and two fish-plates being shown in a cross- section extending perpendicularly to the longitudinal direction of the rail, 3 Fig. 2 shows a partial cross-section and partial top view of the screw clamp, Fig. 3 shows a view of the screw clamp perpendicularly to the longitudinal direction of the rail or in the longitudinal direction of a tightening screw, Fig. 4 shows a greatly enlarged view of a partial region of the clamping piece with a part of a safety flap, and Figs. 5 and 6 as well as 7 and 8 each show two different partial views of a further embodiment of a blocking device in simplified representation.

A screw clamp 1, shown in Figs. 1 to 3, consists essentially of two clamping pieces 2 which are connected to one another by means of two tightening screws 3. on the side facing a rail 4, each of the two clamping pieces 2 has a longitudinal groove 5 for receiving rail bases 6 of the rails 4. Also associated with each clamping piece 2 is a nose- shaped contact part 7 for application to a fish-plate 8 extending in the longitudinal direction of the rail. Each of the tightening screws 3 extending perpendicularly to the longitudinal direction of the rail is provided with a nut 9. In order to prevent a rotation or loosening of said screw connection, a safety flap 10 is provided on each clamping piece 2 on the side facing the nut 9.

Associated with each clamping piece 2 above the respective nut 9 are two brackets 11 spaced from one another with regard to the longitudinal direction of the rail and extending parallel to one another. As evident particularly in Figs. 1 and 4, each bracket 11 has a slot-shaped guide 12. Each safety flap 10 positioned between the two brackets 11 is provided at its upper end with two pins 14 arranged concentrically with respect to a pivot axis 13. Each of said pins 14 is mounted in the 4 adjacent guide 12 for displacement along the longitudinal axis 15 thereof.

As can be seen particularly in Fig. 4, for forming a blocking device 16, an upper end 17 of the safety flap 10 is elongated beyond the pivot axis 13, forming a blocking lug 18. Additionally, a distance (a) of the longitudinal axis or centerline 15 of the guide 12 from an immediately adjacent blocking section 19 of the clamping piece 2 is designed to be smaller in a lower end region of the guide 12 than in an upper end region 20.

Each safety flap 10 is formed of two sections 21,22 arranged one following the other with regard to the longitudinal direction thereof. The lower section 22, when assuming its position for safeguarding against rotation, is arranged perpendicularly to a longitudinal axis 23 of the tightening screw 3, and the upper section 21 is inclined in the direction towards the clamping piece 2.

The safety flap 10, evident in Figs. 1 to 4, is positioned in each case in its lowermost displacement position (shown in full lines) and thus effects a safeguarding against rotation of the associated nut 9. In said lowermost position, pivoting of the safety flap 10 about the pivot axis 13 is not possible since, after even a minute pivoting movement, the blocking lug 18 already contacts the blocking section 19 of the clamping piece 2 (see dash-dotted lines in Fig. 4), and a lifting-off of the lower section 22 of the safety flap 10 from the nut 9 is thereby reliably precluded.

To cancel the safeguard against rotation, it is necessary first to displace the safety flap 10 in the two guides 12 vertically in the direction of the longitudinal axis 15 until the lower end of the lower section 22 comes to lie above the nut 9. Subsequently, since the distance to the blocking section 19 is greater in the upper end region of the guide 12, the safety flap 10 can be pivoted upwards in order to unimpededly be able to loosen the nut 9 from the tightening screw 3 (see dash-dotted line).

In the embodiments of a blocking device 16 shown in Figs. 5 and 6 as well as 7 and 8, parts having the same function are, for the sake of simplicity, denoted by the same reference numerals as in the first-named embodiment. As evident in Figs. 5 and 6, in a portion projecting over the bracket 11, the blocking device 16 has a blocking end 24 deviating from the circular cross-section of the pin 14. Said blocking end 24 is in this case designed in the shape of a cam, for example. In the lower end region of the guide 12, a blocking part 25, serving as a form-fitting safeguard for the safety flap 10 against rotation and receiving the blocking end 24, is connected to the bracket 11. This kind of blocking device 16 ensures that the safety flap 10 in its lowermost position for safeguarding against rotation is not pivotable about the pivot axis 13 due to the form- fitting connection between the blocking end 24 and the blocking part 25. Said pivoting can be carried out only when the safety flap 10 is lifted up and spaced vertically from the tightening screw 3 (not shown) until the blocking end 24 is distanced far enough from the blocking part 25.

As can be seen in Figs. 7 and 8, the blocking device 16 is formed, on the one hand, by a blocking lug 18 projecting beyond the bracket 11 and connected to the pin 14, and, on the other hand, by a blocking part 26 adjoining the lower region of the guide 12 and connected to the bracket 11.

6

Claims

Claims:

1. A screw clamp for temporarily connecting two successive rails of a track, preferably with the aid of fish-plates, particularly for making a suspended butt joint, the rails each comprising a rail head having a running surface, a rail web extending perpendicularly to the running surface, and a rail base extending parallel to the running surface, the screw clamp consisting of a respective clamping piece on either side of the corresponding rail and at least one tightening screw connecting the two clamping pieces and having a respective nut and a safety flap associated therewith, the safety flap being fastened to the clamping piece and adjustable with respect thereto and serving for form-fittingly safeguarding the nut against rotation, characterized in that the safety flap is displaceably mounted in a guide of the clamping piece for spacing the safety flap from the tightening screw, and a blocking device is provided for automatically precluding a pivoting movement of the safety flap with distancing from the tightening screw as soon as the safety flap reaches the lowermost displacement position.

2. A screw clamp according to claim 1, characterized in that the clamping piece comprises two brackets extending parallel to one another above the tightening screw or nut and having a respective slot-shaped guide in which a pin, connected to an upper end of the safety flap, is respectively mounted for displacement in the longitudinal direction of the guide.

3. A screw clamp according to claim 2, characterized in that for forming the blocking device, an upper end of the safety flap is elongated beyond a pivot axis formed by the two pins and forms a blocking lug, and that the distance (a) of a longitudinal axis of each slot-shaped guide from an immediately adjacent blocking section of the clamping piece is designed to 7 be smaller in a lower end region of the guide than in an upper end region.

4. A screw clamp according to one of claims 1, 2 or 3, characterized in that the safety flap is formed of two sections arranged one following the other with regard to the longitudinal direction thereof, with the lower section, when assuming the position for safeguarding against rotation, being arranged perpendicularly to the longitudinal axis of the tightening screw, and the upper section being inclined in the direction towards the clamping piece.

5. A screw clamp according to claim 3, characterized in that the distance, extending perpendicularly to the pivot axis, between the clamping piece and the longitudinal axis of the guide in the upper end region thereof is designed to be greater than the length of the blocking lug.

6. A screw clamp according to claim 1 or 2, characterized in that at least one pin, having a circular cross-section extending perpendicularly to the pivot axis, comprises a blocking end deviating from the circular cross-section in a portion projecting over the guide or the bracket for forming a blocking device, and that a blocking part, serving as a formfitting safeguard for the safety flap against rotation and receiving the blocking end, is connected to the bracket in the lower end region of the guide.

7. A screw clamp, substantially as herein described with reference to the accompanying drawings.