GB2123511A

GB2123511A - T-Bolt

Info

Publication number: GB2123511A
Application number: GB08318233A
Authority: GB
Inventors: Michael Richard Rushmer
Original assignee: Acrow Ltd UK
Current assignee: Acrow Ltd UK
Priority date: 1982-07-13
Filing date: 1983-07-05
Publication date: 1984-02-01
Also published as: GB2123511B; GB8318233D0

Abstract

A T-bolt has a threaded shank and an elongated head, the head extending either side of its axis in a first direction (6) substantially greater to its extension in a second direction (8). The elongate head enables it to be twisted from a position in which it engages a slot in a channel to a slot disengaging position. The T-bolt also has projections (44, 46) which ensure that after twisting of the bolt, the bolt can be easily removed from a T-slot throat. End faces 12, 14 are inclined at 75 DEG to faces 20, 22, and cut-away portions 28, 30 are provided to assist in locating the head in a T-slot. <IMAGE>

Description

SPECIFICATION Improvements in and relating to tee bolts The present invention relates to T-bolts which are particularly suitable for insertion in long T-slots such as may be provided on elongated beams.

The use of T-bolts the head of which engages in a T-slot is well known. They are commonly used to bolt components on to a slotted member such as a machine bed plate. Usually the slots are fairly short so that the T-bolt head is easily slid along the slot a short distance to where it is required for use, there being no intervening obstruction in the slot to prevent the head being slid to the required position. The bolt has a cylindrical head that is with a circular outer periphery when seen in the axial direction. As machine bed plates are not normally very long there is no disadvantage and the bolts are easy to make.

When, however, T-bolts are applied to long slots and the bolts have to be removed frequently, the removal and insertion of the bolts is time consuming. If any intervening member blocks the slot then the bolt cannot be removed.

A T-bolt according to the invention comprises a threaded shank and head, the head extending either side of its axis in a first diametral direction a substantially greater distance to its extension in a second diametral direction, the second direction being at right angles to the first direction, so that the head is elongate in the first direction.

The elongate head of the T-bolt according to the invention enables it to be twisted from a slot engaging position in which the elongation is across the slot to a disengaged position in which the elongation is parallel to the slot when the reduced head width enables the bolt to be removed from the slot without sliding it to the end of the slot.

In a preferred T-bolt according to the invention the head is provided with at least one projection, an abutment of which extends from the shank towards the elongate extremities so that the head is prevented from rotation in the slot past a point where the head can be removed from the slot in an axial direction.

The or each projecting surface facilitates the removal of the bolt from the slot particularly when the head cannot be seen.

Preferably the slot and head are so dimensioned that the head extends in the first direction an extreme distance greater than the width of the interior of the slot so that when the bolt head is inserted into the slot and turned to a slot engaging position the elongated part of the head cams against the interior of the slot. The head is suitably formed so that the camming action takes place in a direction of tightening of the nut for the bolt.

Preferably the elongate head has parallel extreme ends as seen axially which are angled to the first direction at about 75 ; the projection may have one surface substantially parallel to the extreme ends and another surface substantially parallel to the first and elongate direction; the surfaces of the head are limited in the second direction at least partially by parallel surfaces substantially parallel to the first direction.

Preferably the surfaces of the head limited in the second direction have cut away portions substantially at right angles to the extreme ends so that on removal of the bolt from the slot the projection is engaging with the outer part of the slot, the corners of the elongate ends of the head do not catch inside the outer part of the slot.

Preferably the surfaces of the head limited in the second direction are substantially tangential to the shank at least where they meet the shank.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a perspective view of the bolt of the invention, Fig. 2 is a shank end view of the bolt of Fig. 1 but on an enlarged scale, Fig. 3 is a side view of the bolt of Fig. 1 inserted in a slotted H beam and in the insertion or removal position, and Fig. 4 is a view of the beam of Fig. 3 with the bolt of Fig. 1 in the slot engaged position and showing the bolt's use with a clamp securing a soldier (only partly shown) to the beam.

The T-bolt 1 as seen in Fig. 1 has a head 2 and threaded shank 4. The head as seen in Fig. 2 may be defined in relation to a first diametral or elongate direction 6 and a second or transverse direction 8 at right angles to the first direction and passing through the shank axis 10.

The head has parallel extreme ends 12 and 14 with corresponding end surfaces 1 6 and 1 8 which are angled at about 75 to the elongate direction 6. The head also has parallel transverse sides 20 and 22 with corresponding side surfaces 24 and 26 which are parallel to the elongate direction 6. Further edges 28 and 30 correspond to surfaces 32 and 34 which form cut away portions, substantially at right angles to surfaces 1 6 and 1 8 respectively forming corners 33 and 35 therewith.

The surfaces 32 and 34 meet surfaces 24 and 26 respectively at lines 36 and 38 which when projected axially in the direction of the shank approximately form the tips 40 and 42 of projections 44 and 46 which project from the head and shank towards the elongate ends 12 and 14 of the head. The projections have first surfaces 48 and 50 substantially parallel to the extreme ends 12 and 14 and second surfaces 52 and 54 substantially parallel to the first direction.

In Figure 4 there is seen a H-section beam 60 having a T-slot 61 formed in the lower part of the beam. The T-slot has interior longitudinal surfaces 62 distanced apart a distance a which in one example is 20 mm and inner slot depth h suitably 10 mm. The slot has a throat 63 with longitudinal sides 64 a distance apart d suitably 14 mm and a throat depth t suitably 6 mm. For this size of T-slot the bolt 1 has a shank diameter D of 12 mm which equals the head width as taken between sides 20 and 22, an extreme width of 24 mm taken between corners 33 and 35, a distance apart between ends 12 and 14 taken at right angles to the parallel sides of 19 mm, a head depth H (see Figure 1) of 8.4 mm and a projection depth H' of approximately 3.5 mm.

In operation the bolt 1 is inserted into the slot 61 through the throat 63 in the position shown in Figure 3 and as indicated in Figure 2.

The bolt is then turned in a clockwise direction assuming a right hand thread on the bolt into the position shown in Figure 4 and as indicated in Figure 2. A clamp 70 or any other suitable fitment is placed over the bolt to lock against a flange 72 of a soldier 74 abutting on the under surface of the beam 60. A nut 76 is then piaced on the shank of the bolt 1 and tightened to clamp the soldier 74 to the beam 60. To remove the beam 60 from the soldier or vice versa it is merely necessary to slacken the bolt 76, allow the bolt to rotate in an anti-clockwise direction to the position shown in Fig. 3 so that the bolt head is then free to be removed from the slot 61.It will be appreciated that on removal of the bolt from the slot as it is rotated anti-clockwise the projections 44 and 46 come into contact with the throat sides 64 to prevent the ends 12 and 14 of the slot from twisting back under the edges of the throat 63 so as to automatically align the narrow part of the head with the throat 63. Furthermore when the nut 76 is tightened on to the bolt, the bolt will tend to twist in a clockwise direction so that the corners 33 and 35 cam and jam against the inner surfaces 62 of the T-slot so as to prevent movement of the bolt longitudinally in the slot.

It will be appreciated that there are a number of advantages for the bolt as described. Firstly the bolt 1 may be inserted in the slot in any position along the slot between obstructions in the slot without having to insert the bolt at the end of the slot like a conventional T-bolt. Secondly in a tightened situation the described T-bolt 1 locks itself in the T-slot preventing longitudinal movement and indeed lateral movement in the slot. Thirdly the projections 44 and 46 always ensure that when removing the bolt the bolt head will always easily come out of the T-slot throat by simply twisting the bolt the fullest extent possible in an anti-clockwise direction (this of course is with a right handed screwed bolt). Lastly the bolt is strong and economical to manufacture.

The bolt is preferably provided with a member (not shown) at the shank end so as to indicate the position of the head when within the T-slot, whereby a check may be made to see if the head is correctly positioned either in the slot engaged position or slot removal position. A further member (not shown) may be provided also at the shank end to provide an engageable surface with which the T-bolt may be twisted easily into or out of the T-slot. Alternatively a single member is provided to act as an indicating means and twisting member.

Claims

1. A T-bolt comprising a threaded shank and head, the head extending either side of its axis in a first diametral direction a substantially greater distance to its extension in a second diametral direction, the second direction being at right angles to the first direction so that the head is elongate in the first direction.

2. A T-bolt as claimed in Claim 1 wherein the head is provided with at least one projection, an abutment of which extends from the shank towards the elongate extremities.

3. A T-bolt as claimed in Claim 2 wherein the projection has one surface substantially parallel to the extreme ends and another surface substantially parallel to the first and elongate direction.

4. A T-bolt as claimed in Claim 3 wherein both said surfaces of the projection are tangential to the shank.

5. A T-bolt as claimed in any preceding claim wherein the elongate head has parallel extreme ends as seen axially which are angled to the first direction at about 75 .

6. A T-bolt as claimed in any preceding claim wherein the surfaces of the head are limited in the second direction at least partially by parallel surfaces substantially parallel to the first direction.

7. A T-bolt as claimed in Claim 8 wherein the surfaces of the head limited in the second direction have cut away portions substantially at right angles to the extreme ends.

8. A T-bolt as claimed in Claim 6 or 7 wherein the surfaces of the head limited in the second direction are substantially tangential to the shank at least where they meet the shank.

9. A T-bolt as herein described with reference to the accompanying drawings.