GB2302716A - A machine guard having lockable ball bearing means - Google Patents

Abstract

A machine guard, eg for a drilling or milling machine, comprises a mounting ring 11 which is movably mounted onto a non-rotatable part, eg the barrel of a drilling machine. Mounting ring 11 includes ball bearings 51, positioned in locking bores 52, which are forced against the barrel by tightening, eg with a screw driver or Allen key, locking screw 54, thereby securing the ring 11 against movement. Ball bearings 51 are biased by spring 53 which allows the ring 11 to rotate about the barrel when the screws 54 are released. The guard further comprises an axially moveable sleeve that by sliding relative to a tubular part makes visible a tool mounted in the machine.

Description

IMPROVEMENTS IN OR RELATING TO MACHINERY GUARDS The invention concerns machinery safety guards, and has more particular, though not exclusive reference to guards for machines which employ a rotating cutter or like tool rotating about a vertical axis, such as vertical milling machines or drilling machines.

Guards are known for use with drilling machines which comprise a part-cylindrical, transparent shield intended, when in a position of use, to be disposed coaxially with the drill bit, the shield extending partially around such a bit in the peripheral direction thereof. In order to provide ready access to the chuck for the purpose of drill inspection, drill changing or the like, or to facilitate inspection of the workpiece, the shield is movably mounted on a ring secured to the quill or barrel of the drilling machine, being adjustable between a first, or operative position, wherein the shield and drill bit are arranged in coaxial relationship, and a second, or inoperative position, wherein the shield is pivoted upwardly and away from the drill bit about an horizontal axis transversely of the axis.of the drilling head, against the restraint of spring means, the spring means holding the shield in one or other of the two extreme positions when in such position.

Other arrangements are known wherein the shield is pivotal about a generally vertical axis as defined by one or more hinges provided at a lateral edge of the shield and whereby such shield is mounted on a guard body.

A guard of the first mentioned type is disclosed in our prior Patent Application No. 2062154 and comprises a body, said body having an annular part for application to a non-rotatable part of said machine in generally coaxial relationship with a tool to be carried by such machine, and a tubular part on which there is slidably mounted a sleeve adapted and arranged so as to make visible the region of the tool and freely movable in the axial direction of the tubular part, and an adaptor ring adapted to fit within said annular part, said adaptor ring having an outer diameter substantially equal to the inner diameter of said annular part and having a slit therethrough whereby the adaptor ring is closable around said non-rotatable part of said machine.

Such a guard is inexpensive, is easily fitted to a machine, provides excellent protection for the machine operation and is convenient in use.

However it has become necessary to provide a more secure attachment of the mounting ring to the quill or barrel of the drilling machine in order to ensure that the attachment is safe.

According to the present invention therefore there is provided a machinery safety guard comprising a body, said body having an annular part for application to a non-rotatable part of a drilling machine or the like in generally coaxial relationship with the tool to be carried by such machine and a tubular part on which there is slidably mounted a sleeve adapted and arranged so as to make visible the region of the tool and freely movable in the axial direction of the tubular part, said annular part being mounted on said non-rotatable part by way of resiliently biassed bearing means thereby allowing rotational movement of said part relative to said non-rotatable part, and further including a locking means which acts on said bearing means to lock said part against movement relative to said non-rotatable part.

By means of this invention the adaptor ring can be secured in position on the machine in a particularly simple and convenient manner.

The annular part may be integral with the tubular part or, preferably, the annular part comprises a mounting ring and the tubular part is releasably attachable thereto.

One embodiment of the invention will now be further described with reference to the accompanying drawing the single figure of which shows a perspective view of a mounting ring for use in the machinery guard of the present invention.

Referring now to the drawing there is shown a mounting ring 11 for a guard structure of the type described in our earlier UK Patent No.

1566727. As the guard structure is more completely described in our above Patent in terms of its construction and operation, no further description will be given herein.

The guard shown in this Patent is, in use, intended to be fitted to the barrel or quill of a drilling vertical milling or like machine to prevent swarf from causing injury to an operator. A part of the guard structure can swing and slide relative to another part thereof and the whole guard structure can be rotated relative to the barrel or quill by rotation of the mounting ring 11, on which the guard structure is mounted, on roller ball bearing catches.

It has been realised that whilst the guard structure described in our prior Patent mentioned above is effective in increasing the safety of the machine, safety can be improved still further by allowing the whole guard structure to be lockable relative to the barrel 13. The single drawing shows a mounting ring 11 adapted for this purpose.

The internal surface of the mounting ring 11 has a groove therein which receives roller ball bearings 51. Each ball bearing 51 is mounted at an internal end of a locking bore 52, the external end projects freely from the external surface of the mounting ring 11. Each roller ball bearing 51 is biassed towards the internal end of the locking bore 52 by a spring 53 and, in use, is biassed into contact with the barrel 13. The internal wall of each locking bore 52 is screw threaded to receive a locking screw 54 thereinto, which locking screw can be screwed into the respective bore 52 and into contact with the respective roller ball bearing 51.Thus it will be appreciated that, in use, with the mounting ring 11 mounted on the barrel 13, if each locking screw 52 is screwed into a respective locking bore 52 into contact with the roller ball bearing 51, each ball bearing 51 can be secured between the locking screw 54 and barrel 13. In this position it will be appreciated that the mounting ring 11 cannot move relative to the barrel 13.

Accordingly, since the machine guard is mounted on the mounting ring 11, the guard is restrained from swinging relative to the barrel 13. Thus it can be seen that with the arrangement of the present invention it is possible to conceive the safety of the machine guard in use by allowing the guard to be locked against swinging by use of the locking screw.

If desired the locking screw can be adapted to be tightened by a conventional screw tightener, e.g. screw driver or may be adapted to be tightened using an Allen key or any other suitable means as desired or as appropriate.

Claims (7)

1. A machinery safety guard comprising a body, said body having an annular part for application to a non-rotatable part of a drilling machine or the like in generally coaxial relationship with the tool to be carried by such machine and a tubular part on which there is slidably mounted a sleeve adapted and arranged so as to make visible the region of the tool and freely moveable in the axial direction of the tubular part, said annular part being mounted on said non-rotatable part by way of resiliently biassed bearing means thereby allowing rotational movement of said part relative to said non-rotatable part, and further including a locking means which acts on the said bearing means to lock said part against movement relative to said nonrotatable part.

2. A guard according to claim 1 wherein the annular part is integral with the tubular part.

3. A guard according to claim 1 wherein the annular part comprises a and the tubular part is releasable attachable thereto.

4. A guard according to any one of claims 1 to 3 wherein said resiliently biassed bearing means are mounted on a groove on a internal surface of said annular part.

5. A guard according to any one of claims 1 to 4 wherein said resiliently biassed bearing means are positioned at a central end of a locking bore which extends diametrically through said annular part.

6. A guard according to claim 5 wherein said locking means comprises a locking member which is capable of extending through said locking bore and into contact with said resiliently biassed bearing means thereby to prevent rolling motion thereof.

7. A guard substantially as hereinbefore described with reference to the accompanying drawings.