GB2196276A

GB2196276A - Rig with plurality of drills

Info

Publication number: GB2196276A
Application number: GB08618078A
Authority: GB
Inventors: Kenneth Alfred Cochrane
Original assignee: Mcgregor
Current assignee: Mcgregor
Priority date: 1986-07-24
Filing date: 1986-07-24
Publication date: 1988-04-27
Also published as: GB8618078D0

Abstract

The rig for forming holes horizontally into a concrete slab has a substantially rectangular frame having front and rear supports 3,4 and side guides 5. The front support includes a timber edge for locating the rig relative to the slab in use. A drill slide 8 is supported on the side guides 5 and is movable along the side guides so as to move a plurality of rock drills 13 supported on the drill slide into contact with the slab. A first plurality of cylinders 17 are provided on the drill slide for adjusting the spacing between the respective rock drills, and a second plurality of cylinders 9 are provided on the frame for moving the slide 8 and drills into contact with the slab and for applying sufficient pressure to cause the drills to drill respective holes as desired. <IMAGE>

Description

SPECIFICATION Hole forming means This invention relates to a new hole forming means particularly for drilling holes into concrete roads.

Over a number of years concrete slabs or pavements have been used for roads and railway track base, for example, and an increasing number of such concrete slabs are coming up for repair. Particularly in road carriageways, a singificant amount of the repairs are of full depth, i.e. to the total thickness of the concrete slab. The newly laid slab is mechanically locked to the periphery of the adjacent old slab by means of steel dowel bars of 25 mm diameter or thereabouts which protrude from the old slab and form a mechanical lock with the new slab to be laid. In order to accommodate the dowel bars in the old slab, holes of sufficient diameter are drilled at nominal 300 mm centres, the dowels being fixed in position with epoxy resin or similar material.Traditionally the holes are formed with hand held rock drills using a simple jig by which means it is possible to adjust individual hole positions to avoid areas where a hole cannot be drilled (for example where a reinforcing rod intrudes into the area) or where for other reasons (e.g.

skin patches) it is undesirable.

However, the present method of hole forming is slow and inaccurate.

An object of the present invention is to provide an improved hole forming means.

According to the present invention a hole forming means for forming holes horizontally into a concrete slab comprises a frame means for supporting a plurality of drills on the frame for movement relative to the frame and into contact with the slab, and means for applying pressure to the drills to cause the drills to drill respective holes as desired. Preferably the hole forming means also includes means for altering the spacing between adjacent drills.

In the preferred embodiment of the invention a hole forming rig for forming holes horizontally into a concrete slab comprises a substantially rectangular frame having front and rear supports and side guides, the front support including location means for locating the rig relative to the slab, a drill slide supported on the side guides for movement relative to the frame, a plurality of rock drills supported on the drill slide, first cylinder means on the drill slide for adjusting the spacing between the respective rock drills, and second cylinder means on the frame for moving the drills into contact with the slab and for applying sufficient pressure to cause the drills to drill respective holes as desired.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a plan view of a hole forming means in accordance with the invention; and Figure 2 is a side view of the hole forming means of Fig. 1.

In the drawings a hole forming means 1 comprises a substantially rectangular frame 2 including front and rear supports 3 and 4, and side guides 5. The front support 3 has a timber edge 6 for locating on, and protecting, the edge of the slab 7 (Fig. 2) in which holes are to be formed. The side guides 5 support a movable drill slide 8 which is movable towards and away from the front support 3 by means of two spaced cylinder assemblies 9, the piston rods 10 of which are secured to brackets 11 on the drill slide 8.

The hole forming means 1 includes five rock drills 12 with respective drill stems 13 which are mounted on the drill slide 8 at the desired height for drilling by brackets 14. The drill stems 13 are guided by drill guides 15. A first of the five rock drills 12 serves as a marker drill which may be either of the end rock drills and may be locked to the respective side guide 5 by a marker drill latch 16.

The remaining rock drills 12 are movable along the drill slide 8 relative to the marker rock drill in order to adjust the relative spacing between adjacent drills by means of four cylinder assemblies 17.

The movable head drilling frame described is designed to permit the drilling of holes into the original retained concrete slab (old slab) by avoiding areas where a hole cannot be drilled but still permitting the use of a plurality of drills not only speeding up an operation which is critical to the progress of the job as a whole, but also producing holes drilled more accurately for size and for line and level so that less of the very expensive epoxy resin is required.

In addition it is envisaged that one man will produce 800-1000 holes per day instead of the 200-300 now achieved by a 2-man team.

The embodiment described shows five, air operable, drills. However, as the total air consumption is matched to the output of readily available air compressors, the number of drills could be increased or decreased as circumstances demand, so that each drill can be aligned with the preferred drilling position.

In use the frame 1 is suitably supported and held in position by attachment to one blade of a fork lift truck, or preferably on a similar attachment, itself attached to a vehicle which also carried the air compressor required to operate the drills 12.

The rock drill at whichever end of the frame 2 the operator chooses is designated with the marker drill and is fixed laterally to the frame 2 with the latch 16. The remaining drills 12 are then adjusted relative to the marker drill and to each other along the slide 8 to align with a designated drilling position by the electrical, pneumatical, mechanical or hydraulic cylinder means 17.

The movement of the drills to the slab and the necessary pressure to be applied to the drills is provided by means of the pneumatic cylinders 9 fed through a pressure regulator (not shown) so that the optimum pressure is applied to the slab in the prevailing conditions.

The hole forming rig is designed to hold standard rock drills 12 of proprietary manufacture powered by air as these are the more robust units commonly available, but drills of similar function could be powered electrically or hydraulically if desired.

Claims

1. A hole forming means for forming holes in concrete slab comprising a frame, a plurality of drills supported on the frame for movement relative to the frame and into contact with the slab in use, and means for applying pressure to the drills to cause the drills to drill respective holes as desired.

2. A hole forming means according to Claim 1 further including means for altering the spacing between adjacent drills.

3. A hole forming rig for forming holes horizontally into a concrete slab comprising a substantially rectangular frame having front and rear supports and side guides, the front support including location means for locating the rig relative to the slab in use, a drill slide supported on the side guides for movement relative to the frame, a plurality of rock drills supported on the drill slide, first cylinder means on the drill slide for adjusting the spacing between the respective rock drills, and second cylinder means on the frame for moving the drills into contact with the slab and for applying sufficient pressure to cause the drills to drill respective holes as desired.

4. A hole forming means according to Claim 3 further including means whereby a drill may be locked to a side guide to serve as a marker drill, the remaining drills being movable along the drill slide relative to the marker drill in order to adjust the relative spacing between adjacent drills.

5. A hole forming means substantially as hereinbefore described with reference to and as illustrate in the accompanying drawings.