GB2175259A

GB2175259A - Tractor roll-bar

Info

Publication number: GB2175259A
Application number: GB08607392A
Authority: GB
Inventors: Frederick Williams; Anthony David Coe
Original assignee: CASE EUROP Ltd J I
Current assignee: CASE EUROP Ltd J I
Priority date: 1985-03-28
Filing date: 1986-03-25
Publication date: 1986-11-26
Also published as: GB2175259B; GB8508143D0; GB8607392D0

Abstract

A roll-bar for an agricultural tractor comprises a U-shaped upper portion 15 connected by respective pivot pins to left-hand and right-hand lower portions 10 adapted to be secured to the tractor. The upper portion can be locked in an upright operative position, locked in either of two inoperative positions for work with low clearance, or unlocked and pivoted into an acute angular relationship to the lower portions for carriage when not installed on the tractor. Each leg of the upper portion is connected by a locking pin to the associated lower portion or to a plate mounted on the associated pivot pin. Each plate is adapted to be rigidly connected to the associated lower portion in either of two angular positions or to be disconnected from the associated lower portion. A stop welded to each leg contacts the associated plate when the upper portion is moved into any inoperative position. <IMAGE>

Description

SPECIFICATION Tractor roll-bar The invention relates to a roll-bar, or so-called rollover protection structure, for protecting the driver of an agricultural tractor in the event of the tractor overturning.

The object of the invention is to provide means for alternatively locking an upper portion of the roll-bar in an upright operative position for field work or at least one inoperative position for work with low clearance, for instance in a building with a low doorway. A subsidiary object is to enable the roll-bar to be folded compactly for carriage when not installed on a tractor.

According to the invention, a tractor roll-bar has a U-shaped upper portion capable of being locked in an upright operative position or at least one inoperative position relative to left-hand and righthand lower portions adapted to be rigidly secured to the tractor frame, each leg of the upper portion being connected by a pivot pin to one of the lower portions and by a locking pin either to said one of the lower portions or to a plate mounted on the pivot pin and normally rigidly connected to said one of the lower portions.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings of which Figure 1 is a side elevation of an agricultural tractor with parts broken away to show a roll-bar in operative position in full lines and in inoperative position in broken lines; Figure 2 is a side elevation on a much larger scale of one of the roll-bar's pivot mechanisms, with the roll-bar in inoperative position; Figure 3 is a section on the line 3-3 in Figure 2; and Figure 4 is an exploded view of the roll-bar's upper portion.

Referring now to the drawings, a roll-bar for an agricultural tractor includes left-hand and righthand lower portions or pedestals 10 formed of tubing of rectangular cross-section with respective feet 11 adapted to be adjustably bolted to the tractor's rear axle casing 12 which forms part of its rigid frame 13. Each of the lower portions 10 is adapted to carry one of the tractor's rear mudguards 14. The roll-bar also includes a U-shaped upper portion indicated generally at 15. A channel member 16 welded to the end of each leg 17 of the upper portion 15 is connected by a pivot pin 18 to a lug 19 welded to the associated one of the lower portions 10, the two pivot pins 18 having a common transverse axis 20.The upper portion 14 has a cross-beam 21 with a central diagonal joint (see Figure 4) to accommodate slight width variations due to adjustment of the lower portions 10, which joint is clamped rigidly once the roll-bar has been installed on the tractor by means of set-screws (not shown) passing through clearance holes 22 into screw-threaded holes 23 in a bridging member 24 of channel section which fits within the cross-beam 21. Each leg 17 of the upper portion 15 is also optionally connected by a locking pin 25 either directly to the associated one of the lower portions 10 or to a plate 26 mounted on the associated pivot pin 18. The plate 26 is normally rigidly connected by a set-screw 27 passing through the rear one 28 of two clearance holes in the plate 26 into an internally screw-threaded boss 29 welded to the lug 19.Referring now to Figure 3, the pivot pin 18 comprises a conventional bolt which passes in turn through a spring washer 30, a flanged distance piece 31 which fits in a hole in the plate 26, one of the parallel walls of the channel member 16 and a spacer 32 welded thereto, a sleeve 33 which fits in a bore in the lug 19, and a nut 34 welded to the other parallel wall of the channel member 16, and extends into a clearance hole in the last-mentioned wall. The locking pin 25 comprises a special bolt which has a chamfered zone 35 of larger diameter, a chamfered zone 36 of smaller diameter, a tapered zone 37, and a screw-threaded zone engaging a nut 38 with a square flange 39 non-rotatably accommodated in a square hole in said other parallel wall of the channel member 16. The nut 38 is loosely retained in position by a cover plate 40 secured to the last-mentioned wall.

When the legs 17 of the upper portion 15 are connected by the two locking pins 25 directly to the respective lower portions 10 to lock the upper portion 15 in an upright operative position as shown in full lines in Figure 1, each channel member 16 fits around the upper end of the associated lower portion 10 whilst a tongue 41 projecting from within the upper end of each lower portion 10 engages within the end of the associated leg 17.

Each locking pin 25 passes in turn through a chamfered hole 42 in said one parallel wall of the channel member 16 with which its chamfered zone 36 engages, a hole in one wall of the leg 17, and a tapered hole 43 in the tongue 41 in which its tapered zone 37 fits, and engages the nut 38. When the upper portion 15 is moved into a horizontal inoperative position as shown in Figures 2 and 3 and in broken lines in Figure 1, a stop 44 welded to each channel member 16 contacts the associated plate 26 and the leg 17 is then locked to the plate 26 by the associated locking pin 25 which passes in turn through a chamfered hole 45 in the plate 26 with which its chamfered zone 35 engages, the chamfered hole 42 in the channel member 16 which its chamfered zone 36 does not engage, and the aforesaid hole in one wall of the leg 17, but not through the tapered hole 43 in the tongue 41, and engages the nut 38. To secure the upper portion 15 in a higher inoperative position, say at an inclination of 30 above the horizontal, in order to clear any implement connected to the rear of the tractor, the angular relationship of the plates 26 to the lower portions 10 is adjusted by removing the setscrews 27 at both sides of the roll-bar, passing them through the front ones 46 of the clearance holes in the plates 26, and screwing them back into the bosses 29. To enable the roll-bar to be folded compactly for carriage when not installed on a tractor, its upper portion 15 is locked to the plates 26 and said plates are disconnected from the respective lower portions 10 by removing the two set/ screws 27 so that said upper and lower portions can be pivoted into an acute angular relationship, say 309 to one another and then lashed together.

Claims

1. A tractor roll-bar having a U-shaped upper portion capable of being locked in an upright operative position or at least one inoperative position relative to left-hand and right-hand lower portions adapted to be rigidly secured to the tractor frame, each leg of the upper portion being connected by a pivot pin to one of the lower portions and by a locking pin either to said one of the lower portions or to a plate mounted on the pivot pin and normally rigidly connected to said one of the lower portions:

2. A tractor roli-bar according to claim 1, wherein a stop rigidly secured to the leg contacts the plate when the upper portion is moved into inoperative position.

3. A tractor roll-bar according to either of the preceding claims, wherein the plate is angularly adjustable relative to said one of the lower portions to provide a plurality of inoperative positions.

4. A tractor roll-bar according to any one of the preceding claims, wherein the plate is disconnecti ble from said one of the lower portions to enable the upper and lower portions to be pivoted into an acute angular relationship to one another for carriage when the lower portions are not secured to the tractor frame.

5. A tractor roll-bar according to any one of the preceding claims, wherein the upper portion has a central joint adapted to be clamped rigidly when the roll-bar has been installed on the tractor.

6. A tractor roll-bar constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.