GB2129042A - Clamping device - Google Patents

Abstract

A device for clamping together for example a lattice bridge panel and a transom, comprises a shaped steel body (8) with an upstanding projection (8a) at one end and a hole (8b) at the other end with its axis, extending substantially parallel to the projection (8a). The body has an increased depth bearing portion (8c) intermediate its ends and a bolt (9) extending freely through the hole. The bolt (9) has a head (9a) at one end and a nut (10) screw-threaded upon its other end. In use on a lattice bridge the projection (8a) engages a slot in a vertical panel member, the bearing portion engages the top of the transom and the bolt head engages a recess in a seating associated with a panel chord. <IMAGE>

Description

SPECIFICATION Clamping device This invention relates to a device for clamping together components of metal frame structures such as bridges and has been devised particularly for use with lattice bridge structures of the kind originally disclosed in British Patent 553374.

The general object of the invention is to provide an improved clamping device which obviates the herein after explained disadvantages of existing clamping devices and which is both more simple to manufacture and quicker and easier to fix in position.

The invention is therefore described directly by reference to the accompanying drawings, in which: Figure 1 is a part fragmentary perspective view of a typical junction between part of a lattice bridge panel and a transom; Figure 2 is a fragmentary side view of a transom; Figure 3 is a cross-section in line Ill-Ill of Fig.

2; Figure 4 is a fragmentary plan view of a pegged seating; Figure 5 is an elevation of the pegged seating shown in Fig. 4; Figure 6 is a general view of a currently used clamping device, and Figure 7 is a general exploded view of a clamping device according to the present invention.

Referring firstly to Fig. 1 in conjunction with Figs. 2, 3, 4 and 5, there is shown a pair of panels with vertical members 1 and bottom chords 2.

Each bottom chord 2, adjacent a vertical member 1, has a seating 3 with a laterally facing slot 3a and an upstanding peg 3b. Each transom 4, which is supported on the bottom chords 2, has holes 4a at intervals along the junction of its bottom flange and its web which are penetrated by the pegs 3b in order correctly to locate the transoms 4 relative to the panels.

It is the present custom positively to secure the transoms to the panels by means of clamping devices such as that which is shown in Fig. 6. This clamping device is of articulated welded steel construction and comprises a forked body 5 with an upwardly directed nose 5a at one end and a central screw-threaded block Sb which receives a vice-type clamping screw 6. Attached pivotally to the forked end of the body 5 so as to be swingable in an arc as indicated by the arrows is a coupling arm 7 with a head 7a at its free end.

In use, and referring also to Fig. 1, the nose 5a of the clamping device is inserted into a slot 1 a in a panel vertical, whereafter the head 7a is engaged under its seating slot 3a. Finally the clamping device is tightened by turning the screw 6 which engages the top flange 4b of the transom.

In practice it is found that with vibration of the bridge structure, the clamping device tends to loosen so that periodical maintenance is required.

Furthermore such clamping devices are easily removed by vandals, leaving the bridge structure in a dangerous condition.

The typical clamp in accordance with the present invention which is shown in Fig. 7, comprises a shaped steel body 8 having at one end a nose 8a which is insertable into the slot 1 a of a panel vertical member, and at the other end a hole 8b for receiving a bolt 9. Intermediate its ends, the body 8 is of increased depth so as to define a bearing portion 8c which is intended to make contact with the transom top flange 4b.

The bolt 9 has a head 9a with a projection 9b of a shape complementary to a seating recess 3a to prevent rotation of the bolt 9. The other, upper, end of the bolt 9 is screw threaded and receives a nut 10 which is shaped so as to require a special tool for its tightening or removal. The screw threaded part of the bolt 9 has a patch of proprietary plastics material applied to it for preventing slackening of the nut due to vibration in use.

In alternative versions, the special nut can be replaced by a normal hexagon nut, and a proprietary stiff nut can be used instead of the plastic patch.

Claims

1. A device for clamping together components of metal frame structures comprising: a shaped steel body with an upstanding projection at one end and a hole at the other end with its axis extending substantially parallel to the projection, the body having an increased depth bearing portion intermediate its ends; and a bolt extending freely through the hole and having a head at one end and a nut screw-threaded upon its other end.

2. A device as claimed in claim 1 when used for clamping together a lattice bridge panel and a transom supported by a bottom chord of the panel, the said projection engaging in a slot in an upright of the panel, the said bearing portion being in contact with the top of the transom, the head of the bolt being non-rotatably engaged with a slotted seating associated with the chord and the nut being tightened against the body.

3. A device for clamping together a lattice bridge panel and a transom supported therein substantially as hereinbefore described with reference to Figs. 1 to 5 and Fig. 7 of the accompanying drawings.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Clamping device This invention relates to a device for clamping together components of metal frame structures such as bridges and has been devised particularly for use with lattice bridge structures of the kind originally disclosed in British Patent 553374. The general object of the invention is to provide an improved clamping device which obviates the herein after explained disadvantages of existing clamping devices and which is both more simple to manufacture and quicker and easier to fix in position. The invention is therefore described directly by reference to the accompanying drawings, in which: Figure 1 is a part fragmentary perspective view of a typical junction between part of a lattice bridge panel and a transom; Figure 2 is a fragmentary side view of a transom; Figure 3 is a cross-section in line Ill-Ill of Fig. 2; Figure 4 is a fragmentary plan view of a pegged seating; Figure 5 is an elevation of the pegged seating shown in Fig. 4; Figure 6 is a general view of a currently used clamping device, and Figure 7 is a general exploded view of a clamping device according to the present invention. Referring firstly to Fig. 1 in conjunction with Figs. 2, 3, 4 and 5, there is shown a pair of panels with vertical members 1 and bottom chords 2. Each bottom chord 2, adjacent a vertical member 1, has a seating 3 with a laterally facing slot 3a and an upstanding peg 3b. Each transom 4, which is supported on the bottom chords 2, has holes 4a at intervals along the junction of its bottom flange and its web which are penetrated by the pegs 3b in order correctly to locate the transoms 4 relative to the panels. It is the present custom positively to secure the transoms to the panels by means of clamping devices such as that which is shown in Fig. 6. This clamping device is of articulated welded steel construction and comprises a forked body 5 with an upwardly directed nose 5a at one end and a central screw-threaded block Sb which receives a vice-type clamping screw 6. Attached pivotally to the forked end of the body 5 so as to be swingable in an arc as indicated by the arrows is a coupling arm 7 with a head 7a at its free end. In use, and referring also to Fig. 1, the nose 5a of the clamping device is inserted into a slot 1 a in a panel vertical, whereafter the head 7a is engaged under its seating slot 3a. Finally the clamping device is tightened by turning the screw 6 which engages the top flange 4b of the transom. In practice it is found that with vibration of the bridge structure, the clamping device tends to loosen so that periodical maintenance is required. Furthermore such clamping devices are easily removed by vandals, leaving the bridge structure in a dangerous condition. The typical clamp in accordance with the present invention which is shown in Fig. 7, comprises a shaped steel body 8 having at one end a nose 8a which is insertable into the slot 1 a of a panel vertical member, and at the other end a hole 8b for receiving a bolt 9. Intermediate its ends, the body 8 is of increased depth so as to define a bearing portion 8c which is intended to make contact with the transom top flange 4b. The bolt 9 has a head 9a with a projection 9b of a shape complementary to a seating recess 3a to prevent rotation of the bolt 9. The other, upper, end of the bolt 9 is screw threaded and receives a nut 10 which is shaped so as to require a special tool for its tightening or removal. The screw threaded part of the bolt 9 has a patch of proprietary plastics material applied to it for preventing slackening of the nut due to vibration in use. In alternative versions, the special nut can be replaced by a normal hexagon nut, and a proprietary stiff nut can be used instead of the plastic patch. Claims

1. A device for clamping together components of metal frame structures comprising: a shaped steel body with an upstanding projection at one end and a hole at the other end with its axis extending substantially parallel to the projection, the body having an increased depth bearing portion intermediate its ends; and a bolt extending freely through the hole and having a head at one end and a nut screw-threaded upon its other end.

2. A device as claimed in claim 1 when used for clamping together a lattice bridge panel and a transom supported by a bottom chord of the panel, the said projection engaging in a slot in an upright of the panel, the said bearing portion being in contact with the top of the transom, the head of the bolt being non-rotatably engaged with a slotted seating associated with the chord and the nut being tightened against the body.

3. A device for clamping together a lattice bridge panel and a transom supported therein substantially as hereinbefore described with reference to Figs. 1 to 5 and Fig. 7 of the accompanying drawings.