GB2149465A

GB2149465A - A pneumatically operated power tool

Info

Publication number: GB2149465A
Application number: GB08330462A
Authority: GB
Inventors: Michael John Barnard; Leonard Edward Healy
Original assignee: Desoutter Ltd
Current assignee: Air Compressors and Tools Ltd
Priority date: 1983-11-15
Filing date: 1983-11-15
Publication date: 1985-06-12
Also published as: GB2149465B; DE3441468C2; IT8449167A1; DE3441468A1; FR2554753A1; IT8449167A0; FR2554753B1; GB8330462D0; IT1179490B

Abstract

A power tool comprises a tool body housing a pneumatic motor and means (14, 15, 16, 31) for switching the motor on and off, and a removable adaptor (18) defining an exhaust outlet surrounding an air inlet (17) to the tool, the adaptor being interchangeable with a further adaptor Fig. 11 which defines an exhaust outlet (36) offset from the air inlet. A control top (10) incorporating a valve (14, 15) and adapted to make the tool reversible may be interchangeable with a further control top adapted to make the tool non-reversible. <IMAGE>

Description

SPECIFICATION A Pneumatically Operated Power Tool This invention relates to a pneumatically operated powertool and to a method of assembling such a tool.

Pneumatically operated power tools, e.g.

screwdrivers, grinders, driils are in various different designs. Some have a rear exhaust outlet concentric an air inlet and some have an exhaust outlet at the rear which is offset from the air inlet. The former are used normally when there is no intention of collecting and filtering the exhaust air and the latter when it is the intention to collect and filterthe exhaust air. Others have a front exhaust outlet.

Moreover, some tools are reversible whereas others are not and various different mechanisms are provided for starting the tools. This results in a large range of tools with high concomitant manufacturing costs and often the need for a user to buy several different tools.

According to one aspect of the invention, there is provided a pneumatically operated power tool comprising a tool body housing a pneumatic motor and including a control top having therein an air inlet passage, passage means for directing air from said air inlet passage to said motor and valve means operable to selectively connect and interrupt an air supply to said motor, and at least two adaptors selectively connectible to the control top, one of the two adaptors defining an exhaust outlet surrounding an air inlet to the tool and the other adaptor defining an exhaust outlet offset from said air inlet.

Preferred and/or optional features of said one aspect of the invention are set forth in claims 2-6.

According to a second aspect of the invention there is provided a pneumatically operated power tool comprising a tool body housing a pneumatic motor and means for switching the motor on and off, and a removable adaptor defining an exhaust outlet surrounding an air inlet to the tool (or an exhaust outlet offset from the air inlet to the tool), the adaptor being interchangeable with a further adaptor which defines an exhaust outlet offset from the air inlet to the tool (or an exhaust outlet surrounding an air inlet two the tool).

According to a third aspect of the invention there is provided a pneumatically operated power tool comprising a tool body housing a pneumatic motor and including a control top having therein an air inlet passage, passage means for directing air from said air inlet passage to said motor and valve means operable to selectively connect and interrupt an air supply to the motor, the control top being removable and, when incorporated in the tool, being such as to make the tool non-reversible (or reversible), the control top being interchangeable with a further control top which makes the tool reversible (or non-reversible).

According to a fourth aspect of the invention, there is provided a method of assembling a pneumatically operated power tool, comprising the steps of (a) starting with a tool body housing or adapted to house a pneumatic motor and means for switching the motor on and off, an adaptor for defining an exhaust outlet surrounding an air inlet to the tool and an adaptor for defining an exhaust outlet offset from the air inlet to the tool, and (b) selectively connecting one or other of the adaptors to the tool body.

The invention will now be more particularly described with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a control top and adaptor for reversible auto start pneumatic tool with concentric air inlet and exhaust, Figure 2 is a longitudinal section of the control top and exhaust adaptor of Figure 1 but provided with a lever start mechanism, Figure 3 is a left hand end view of the control top shown in Figures 1 and 2, Figure 4 is a section taken alone line A-A of Figure 1, Figure 5 is a part section taken along line BOB of Figure 1, Figures 69 are longitudinal or part longitudinal sections through a control top and adaptor for a non-reversible pneumatic tool with concentric air inlet and exhaust and each showing a different starting mechanism, Figure 10 is a left hand end view of the control top shown in Figures 9, Figure 11 is a longitudinal section through a first alternative adaptor with offset inlet and exhaust and shows an optional silencer, and Figure 12 is a longitudinal section through a second alternative adaptor for use when front end exhaust is required.

Referring firstly to Figures 1-5, there is shown therein a control top and an adaptor of a pneumatically operated power tool. The control top indicated at 10 is designed to make the tool reversible and includes a button operated spool valve 11 for directing air to a pneumatic motor (not shown) of the tool through a port 12 our a port 13.

The control top also includes a spring biassed valve member in the form of a ball 14which is urged by spring 15 against a valve seat 16 in an air inlet passage 17 in the control top. The adaptor is indicated at 18 and is in the form of a plastics sleeve-like member which has a circumferential groove 19 at one end locating an 0 ring 20. The adaptor 18 is push fitted into the rear end of the control top. The adaptor has therein two annular filters 21 and 22 with a spacer 23 therebetween and is releasably fastened to the control top 10 by a bush 24 provided with 0 ring seals 25 and 26. The bush has an integral nut 27 at one end which engages the annular filter 22 and an external screw thread 28 at its other end which engages with an internal screw thread in the wall of the inlet passage 17 of the control top 10.An air supply conduit (not shown) is fixed to the nut end of the bush 24 and air is supplied to the motor via the air inlet passage 17 and port 12 or 13 depending upon the position of the spool valve 11 and is exhausted from the motor via a crescent shaped port 29 which communicates with the adaptor 18 via a passage 30 in the control top. It will thus be seen that the adaptor 18 defines an exhaust outlet which surrounds the air inlet to the tool and this adaptor is normally used when it is not desired to collect and then filter the exhaust air. A plastics overhose (not shown) can be fitted over the adaptor 18 and retained by an internal protrusion locating in an external groove 18' in the adaptor.

This overhose would extend a distance away from the control top 10 so as to take the exhaust air away from the immediate vicinity of the operator.

The control top is made as a die casting and basically the control tops shown in Fig. 1 and Fig. 2 are the same. However, the control top shown in Fig. 1 is adapted for use in conjunction with an auto start mechanism, that is to say a mechanism which includes an elongate member 31 which raises the ball 14 from its seat 16 when rearward pressure is applied to the tool holder by pressing a drill or other implement supported by the tool holder against a workpiece or the like.

The control top shown in Figure 2 is adapted for use in conjunction with a lever start mechanism comprising a lever 32 pivotably connected to the control top by a pin 33, and a button member 34 which on pivotable movement of the lever raises the ball 14 off its seat 16 by moving ball 14 both sideways and rearwards.

The bore in the control top which locates the button member 34 is not provided in the control top as shown in Figure 1; it is machined in the control top as required. However, as can be seen in Figure 1, a hole is provided for the lever pin 33 although as shown in Figure 5 this is closed off with plastics plug 35.

Instead of the adaptor 18, the control top shown in Figures 1--5 can be used with the adaptor shown in Figure 11. This is in the form of a cranked plastics member which does not contain any filters. It has an exhaust outlet 36 which is laterally offset from the air inlet to the tool and is normally used when the exhaust air is to be collected by connecting a collecting hose to the adaptor, and then filtered.

However, the adaptor shown in Figure 11 can be provided optionally with a silencer 37, instead of the collecting hose.

The control top of Figures 1-5 can also be used with a plastics adaptor shown in Figure 12. This adaptor is designed to prevent any exhaust air exiting from the rear of the control top and is in the form of a stepped sleeve. The larger diameter end 38 of the sleeve sealingly engages, via an 0 ring seal 38' with the control top and the smaller diameter end 39 sealingly engages with the bush 24 via an O ring seal 40. The adaptor of Figure 12 will be used when it is desired to exhaust the air from the motor from the front end of the tool, in which case the front end of the tool will need to be modified to provide one or more exhaust openings therefrom.

Figures 6--9 show an alternative control top in conjunction with the adaptor shown in Figures 1 and 2. The control top of Figures 69 is very similar to that of Figures 1-2 but in this case there is no provision for the button operated spool valve 11 used to reverse the motor. The air inlet passage in the control top terminates in a recess 41 (as seen more clearly in Figure 10) and a crescent shaped exhaust port 42 leads into exhaust passage 30. As seen in Figure 10, the control top has two blind holes 44 and 45. A small spigot on that part of the body of the tool which houses the motor is arranged to fit in one of the holes 44 or 45 and depending upon the hole in which the spigot is fitted the motor will be arranged relative to the recess 41 and the exhaust port 42so as to rotate in one or other direction.

The control top shown in Figure 6 has an auto start mechanism similar to the control top shown in Figure 1 and the control top shown in Figure 8 has a lever start mechanism similar to that shown in Figure 2.

The control top shown in Figure 7 has a push button start mechanism in which the lever of Figures 2 and 8 is simply replaced by a head detachably fastened to the outer end of button member 34.

The control top of Figure 9 has a lever start mechanism, but this is provided with a safety device to prevent operation of the lever accidentally and is described more particularly in our British Patent No.

2070207.

The control tops of Figures 69 can be used with the adaptor of Figure 11 or indeed with the adaptor of Figure 12 instead of the adaptor as shown in Figures 69 in like manner two that described above with reference to Figures 1 and 2.

Consequently, a number of different machine tools can be manufactured at much reduced cost and the user can change his tool from a reversible tool to a non-reversible tool which can exhaust to the rear concentrically with the air inlet or offset from the air inlet or can exhaust to the front and which can be provided with any one of a number of different start mechanisms.

Claims

IA A pneumatically operated power tool comprising a tool body housing a pneumatic motor and including a control top having therein an air inlet passage, passage means for directing air from said air inlet passage to said motor and valve means operable to selectively connect and interrupt an air supply to said motor, and at least two adaptors selectively connectible to the control top, one of the two adaptors defining an exhaust outlet surrounding an air inlet to the tool and the other adaptor defining an exhaust outlet offset from said air inlet.
2. The tool of claim 1,wherein each adaptor is push fittable into an opening in the control top and is held therein by a bush which defines the air inlet to the tool and which extends through the adaptor and screw threadably engages with the wall of the inlet passage in the control top.
3. The tool of claim 1 or claim 2, wherein the control top is of generaliy cylindrical shape, the control top having its air inlet passage and an exhaust outlet passage communicating with the rear end of the control top, i.e. that end remote from a tool holder, and the adaptors being connectible to the rear end of the control top.
4. The tool of claim 3, comprising a further adaptor for blanking off the exhaust outlet passage communicating with the rear end of the control top.
5. The tool of any one of the preceding claims and comprising first and second control tops selectively incorporatable in the tool, the first control top being for making the tool reversible and the second control top being for making the tool non-reversible.
6. The tool of claim 5, wherein each control top is adapted to operate selectively with at least two different starting mechanisms.
7. A pneumatically operated power tool comprising a tool body housing a pneumatic motor and means for switching the motor on and off, and a removable adaptor defining an exhaust outlet surrounding an air inlet to the tool (or an exhaust outlet offset from the air inlet to the tool), the adaptor being interchangeable with a further adaptor which defines an exhaust outlet offset from the air inlet to the tool (or an exhaust outlet surrounding an air inlet to the tool).
8. A pneumatically operated power tool comprising a tool body housing a pneumatic motor and including a control top having therein an air inlet passage, passage means for directing air from said air inlet passage to said motor and valve means operable to selectively connect and interrupt an air supply to the motor, the control top being removable and, when incorporated in the tool, being such as to make the tool non-reversible (or reversible), the control top being interchangeable with a further control top which makes the tool reversible (or non-reversible).
9. A pneumatically operated power tool, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
10. A method of assembling a pneumatically operated power tool, comprising the steps of (a) starting with a tool body housing or adapted to house a pneumatic motor and means for switching the motor on and off, an adaptor for defining an exhaust outlet surrounding an air inlet to the tool and an adaptor for defining an exhaust outlet offset from the air inlet to the tool, and (b) selectively connecting one or other of the adaptors to the tool body.