DESC:FIELD OF THE INVENTION

The present invention relates to a device for preventing injury to machine operators. In particular, the present invention relates to a device for preventing fingers of the machine operators getting trapped during spindle rotation in a drilling machine. More particularly, the present invention relates to an automatically operated safety guard for radial drilling or single spindle drilling machines.

BACKGROUND OF THE INVENTION

Normally, in the shop floor of any manufacturing plant, the drilling machine operator is supposed to use hand gloves only for handling components. However, it is often observed that machine operator continues to use hand gloves even for changing tools while performing the drilling operation on such machines.

This an extremely unsafe act on the shop floor, and the hand gloves frequently get trapped between the Quick Change Chuck and the spindle of the drilling machine. This often causes serious finger injuries to the machine operator.

The present manufacturer of the radial drilling machine and single spindle drilling machine have not provided any safety guard for protecting the fingers of the machine operator from getting trapped in the above discussed manner. The shop-floor personnel at the manufacturing facilities of present applicant have recorded a number of such accidents in the past, where drilling machine operators have finger injuries.

To prevent occurrence of such accidents during operation on such drilling machines and single spindle machines etc., it was felt prudent to develop an in-house device, which prevents operator to change the tool while drilling machine spindle is still rotating. Accordingly, a thorough study of the drilling operation on the radial drilling machines as well as on the single spindle drilling machines was conducted.

PRIOR ART

US Patent 4,132,497 discloses a guard for protecting a drilling machine operator from a drill bit mounted in a vertical drilling machine. The guard comprises a multi-part shield which when operative at least substantially surrounds the drill bit, a tubular protecting member adapted to be attached to the quill of the drilling machine and extending downwardly beneath the quill and within the shield, and means for connecting the shield to the protecting member whereby the shield is suspended therefrom, the shield extending upwardly to a height at least equal to the lower end of the protecting member, and at least one part of the shield being movable between its operative position and an inoperative position which allows access to the drill bit. The protecting member is preferably a split ring which is clamped around the quill and the shield is preferably formed of two half-shields of transparent plastics material attached by a slide to the protecting member.

US Patent 5,908,272 discloses a guard apparatus for a rotational tool prevents direct contact of the cutting regions by an operator of the tool. The rotational cutting tool to which this invention is particularly applicable is the type having at least a shank portion and a toothed region, with the shank portion attachable to a holding attachment device to hold the tool, particularly during operation. The guard apparatus comprises a compressible guard housing for defining a guard circumferential area following a circular path parallel to but greater than a cutting circumferential area defined by the toothed region of the rotational cutting tool; and a first securement device having a first periphery at a first end for abutting the holding attachment device and a flared and tapered periphery at a second end for associating with the compressible guard housing.

WO 1997/035145 discloses a machine safety guard unit system having a flexible panel moved upwards and downwards between track members with the system positioned between the operative parts of a machine and a machine operator, such panel when closed protecting the machine operator and when moved upwards into its open mode, allowing access to the machine and preventing the machine from operating. In some embodiments more than one of such units can be disposed around a machine with alarm means; and in yet other embodiments, with inter-engagement means connecting such units.

US Patent 3, 913, 413 discloses a safety guard structure including a guard member adapted to be interposed between a mechanism such as a punch press and the operator thereof to protect the operator from injury. In one form of the invention the guiding frame for guiding the guard member between its upper and lower positions is swingably connected to the mechanism to be guarded to permit the entire guiding frame to be swung upwardly so as to present no interference when it is desired to modify the mechanism or to change the dies thereof. In another form of the invention the guide structure for the guard member is entirely positioned above the area to be protected so as to present no interference when it is necessary for operators to work around the machine. An interlocking device is provided to prevent operation of the mechanism except when the guard member and its guide structure are in proper operating position.

US 20110259060 discloses a safety switch for generating a system enable signal depending on the position of a movable guard door which is used for safeguarding a hazardous area of a machine installation. At least one part of the machine installation can only be operated when the system enable signal is present. The safety switch has a door part to be fastened to the movable guard door and a frame part to be fastened to a mating door piece. The safety switch also has a bolt which can be moved between a first position and a second position, a recess in which the bolt can engage in the second position, and a locking element designed to block the bolt in the second position. In addition, the safety switch comprises a first position sensor designed to clearly detect at least one of the positions of the bolt in order to generate the system enable signal. Moreover, the safety switch comprises a door release request unit configured to generate a door release request signal in addition to the system enable signal.

However, none of the above prior arts disclose the features proposed by the present invention.

DISADVANTAGES OF THE PRIOR ART

The presently available manual guards have the disadvantage that the machine operator is required to lift the lower portion of the manual guard every time, when the tool is to be changed. This was not perceived by the operator as user friendly and often, the operator is reluctant to use the same.

At present, the radial drilling machines and single spindle drilling machines do not have any safety guard for protecting the fingers of the machine operator from getting trapped in the above discussed manner.

None of the presently available drilling machines come equipped with automatic means for preventing finger injuries to the machine operator, when access to the tool is made, when the spindle of the machine is still rotating. This is an undesirable practice by the drilling machine operators not to use this manual guard and to bypass this manual guard.

The shop-floor personnel at the manufacturing facilities of present applicant have recorded a number of such accidents in the past, where drilling machine operators have major finger injuries.

DESCRIPTION OF THE INVENTION

Accordingly, a user friendly automatically operated safety guard for preventing injuries to the fingers of the drilling machine operator is developed in-house, which operates automatically with the rotation of the drilling machine spindle.

This automatically operated safety guard is a pneumatically operated safety guard, which is operated by an air-pressure of about 20 psi. This guard is interlocked with the spindle rotation, so that there is no scope at all for the drilling machine operator to bypass this safety guard for accessing and/or changing tools while spindle is still rotating.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an automatically operated device for preventing injuries to the fingers of the machine operator.

Another object of the present invention is to provide an automatically operated safety guard to prevent access to Quick Change (QC) chuck and machine spindle during spindle rotation.

Yet another object of the present invention is to provide an automatically operated safety guard to allow access to QC chuck and machine spindle only after spindle stops rotating.

A further object of the present invention is to provide an automatically operated safety guard which cannot be bypassed by the machine operator for accessing the tool or spindle, when it is still in rotation.

Still further object of the present invention is to provide an automatically operated safety guard which is cost-effective and can be made in-house.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a safety guard for radial and single spindle drilling machines, wherein the safety guard comprises retractable safety guard cover retractably operated by means of a safety guard retraction mechanism.
Typically, the retractable safety guard mechanism is a pneumatically operated retraction mechanism comprises:

(a) a safety guard cover;

(b) an air-cylinder fitted on a quill supplying compressed air;

(c) a pneumatically operated directional valve;

(d) a lubricator;

(e) pressure reducer valve;

(f) pressure gauge; and

(g) an actuation mechanism consisting of proximity switch, MCB, solenoid valve and electrical contactor;

wherein, the compressed air received from the quill 20 is supplied to the directional valve by means of the air cylinder through an air duct to the lubricator and the pressure reducing valve, the air-pressure in the pressure reducing valve being displayed by means of the pressure gauge PG, the movement of the directional valve connected to the solenoid valve and the electric contactor actuates the solenoid switch for retractably controlling the direction of upward or downward movement of the safety guard cover to allow or deny access to the tool and QC chuck to the machine operator.

Typically, the upward movement of the directional valve connected to the solenoid valve and the electric contactor actuates the solenoid switch for retracting the safety guard cover to allow access to the tool and QC chuck to the machine operator for changing the machine tool, e.g. drilling or boring tool to facilitate changing and/or adjustment thereof.

Typically, the downward movement of the directional valve connected to the solenoid valve and the electric contactor actuates the solenoid switch for covering the machine tool, e.g. drilling or boring tool by the safety guard cover to deny access to the tool and QC chuck while the tool is still rotating for preventing any finger or body part injury to the machine operator.

Typically, the retractable safety guard mechanism is an automatically operated safety guard mechanism operating in a vertical direction.

Typically, the retractable safety guard mechanism is an automatically operated safety guard mechanism operating in a horizontal direction.

Typically, the retractable safety guard mechanism is a hydraulically operated retraction mechanism.

Typically, the retractable safety guard mechanism is an electrically operated retraction mechanism.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, in which:

Figure 1a shows a single spindle or radial drilling machine equipped with the pneumatically operated safety guard in accordance with the present invention;

Figure 1b shows another position of the single spindle or radial drilling machine equipped with the pneumatically operated safety guard in accordance with the present invention; and

Figure 2 shows the schematic arrangement of the operating mechanism of the pneumatically operated safety guard in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the pneumatically operated safety guard in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1a shows a single spindle or radial drilling machine 100 equipped with the pneumatically operated safety guard 12 configured in accordance with the present invention. The drilling machine 100 includes a drilling tool 2 securely retained in a QC chuck 4 drivingly connected to a spindle 6 of the drilling head 8 of the drilling machine 100. The drilling machine 100 includes wheel or handle 10 for starting or stopping the rotation of the spindle 6. Since the drilling machine spindle 6 is still rotating in the condition shown here, the retractable safety guard 12 is in its lowermost position 16. This retractable safety guard 12 is provided for preventing the machine operator (not shown) from accessing the QC chuck 4 and the spindle 6. The drilling machine 100 is mounted over an operating table 14, which can securely hold the work piece or job (not shown) on which the desired drilling operation is to be performed.

Figure 1b shows another position of the single spindle or radial drilling machine 100 shown in Figure 1a. However, the spindle is shown here in its completely stopped position. Therefore, the retractable safety guard 12 is automatically brought to its uppermost position 18 shown by means of a built-in pneumatic safety guard retraction mechanism. In this position, the retractable safety guard 12 of the drilling machine remains retracted upwards (position 18) in order to allow the machine operator to easily access the QC chuck 4 and spindle 6. In this position, the machine operator (not shown) can access the tool/drill or QC chuck for changing the same, as per the desired drilling operation to be performed.

Figure 2 shows the schematic arrangement of the operating mechanism of the pneumatically operated safety guard 12 configured in accordance with the present invention. It consists of a quill 20, an air-cylinder 22, a directional valve 24, lubricator 26 and pressure reducer valve 28. The actuation mechanism includes a proximity switch 30, MCB 32, solenoid valve 34 and electrical contactor 36. The directional valve 24 receives compressed air from the quill 20 via air cylinder 22 by means of air duct and supplies the same to the lubricator and pressure reducing valve 26, 28. The air pressure in this valve is displayed by means of the pressure gauge PG provided thereon. The directional valve 24 is connected to the solenoid valve 34 and the electric contactor 36 for operating the solenoid switch 30 to control the direction of downward movement of the safety guard to cover the tool and QC chuck or to control the upward movement of the same for allowing access to the tool and QC chuck by the machine operator. By using the automatic pneumatically operated safety guard in single spindle/radial drilling machines, the POKAYOKE system is fully implemented. This automatic operation also eliminates the operator fatigue.

It is important to note that although the present invention is explained in terms of a radial drilling machine, in which the machine tool, e.g. drilling tool is moveable in a vertical direction; the principle of the present invention can be employed in any other machine tool, which is moveable in any other direction other than vertical direction.

The idea underlying the present invention can be used by the person skilled in the art by suitably modifying the constructional basic features of the invention to match the direction of movement of the machine tool for the complete safety of the machine operator.

WORKING OF THE INVENTION:

The pneumatically operated safety guard configured in accordance with the present invention operates as discussed in the following:

The directional valve receives compressed air from the quill via the air cylinder by means of the air duct. This compressed air is supplied to the lubricator and pressure reducing valve respectively. The air pressure in this valve is displayed by means of the pressure gauge PG provided thereon. The directional valve is connected to the solenoid valve and the electric contactor for operating the solenoid switch for controlling the direction of downward movement of the safety guard to cover the tool and QC chuck. The directional valve can also be used for controlling the upward movement of the safety guard to open access to the machine operator to access the tool and QC chuck. By using the automatic pneumatically operated safety guard configured in accordance with the present invention discussed above, particularly in single spindle/radial drilling machines, the POKAYOKE system is fully implemented. This automatic operation also substantially eliminates the operator fatigue and finger injuries, which were otherwise common in the trade.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

Some of the technical advantages of the device proposed in accordance with the present invention are as under:

1. Reduced operator fatigue,
2. Elimination of the accidents on radial drilling and single spindle drilling machines,
3. Facilitates compliance of the Safety Requirement at workplace according to the Factories Act, 1948,
4. Causes no production or skill losses at SSD/RD machines,
5. Enhances company image in the eyes of the operator and general public,
6. Reduced insurance claims and medical expenditures caused due to accidents, and
7. Avoids issuance of Show-cause notices to the machine operators involved in accidents caused and reported earlier.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps. However, it does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification. In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples.

However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description.

Therefore, innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The exemplary embodiments were selected and described in order to be able to best represent the principles and their possible practical application underlying the invention. Thereby, the skilled persons can optimally modify and use the invention and its different exemplary embodiments with reference to the intended use. ,CLAIMS:We claim:

1. A safety guard for radial and single spindle drilling machines, wherein the safety guard comprises retractable safety guard cover retractably operated by means of a safety guard retraction mechanism.

2. Safety guard as claimed in claim 1, wherein the retractable safety guard mechanism is a pneumatically operated retraction mechanism comprises:

(a) a safety guard cover;

(b) an air-cylinder fitted on a quill supplying compressed air;

(c) a pneumatically operated directional valve;

(d) a lubricator;

(e) pressure reducer valve;

(f) pressure gauge; and

(g) an actuation mechanism consisting of proximity switch, MCB, solenoid valve and electrical contactor;

wherein, the compressed air received from the quill 20 is supplied to the directional valve by means of the air cylinder through an air duct to the lubricator and the pressure reducing valve, the air-pressure in the pressure reducing valve being displayed by means of the pressure gauge PG, the movement of the directional valve connected to the solenoid valve and the electric contactor actuates the solenoid switch for retractably controlling the direction of upward or downward movement of the safety guard cover to allow or deny access to the tool and QC chuck to the machine operator.

3. Safety guard as claimed in claim 1 or 2, wherein the upward movement of the directional valve connected to the solenoid valve and the electric contactor actuates the solenoid switch for retracting the safety guard cover to allow access to the tool and QC chuck to the machine operator for changing the machine tool, e.g. drilling or boring tool to facilitate changing and/or adjustment thereof.

4. Safety guard as claimed in claim 1 or 2, wherein the downward movement of the directional valve connected to the solenoid valve and the electric contactor actuates the solenoid switch for covering the machine tool, e.g. drilling or boring tool by the safety guard cover to deny access to the tool and QC chuck while the tool is still rotating for preventing any finger or body part injury to the machine operator.

5. Safety guard as claimed in anyone of the claims 1 to 4, wherein the retractable safety guard mechanism is an automatically operated safety guard mechanism operating in a vertical direction.

6. Safety guard as claimed in anyone of the claims 1 to 4, wherein the retractable safety guard mechanism is an automatically operated safety guard mechanism operating in a horizontal direction.

7. Safety guard as claimed in claim 1, wherein the retractable safety guard mechanism is a hydraulically operated retraction mechanism.

8. Safety guard as claimed in claim 1, wherein the retractable safety guard mechanism is an electrically operated retraction mechanism.

Dated this 29th day of January,2015 SANJAY KESHARWANI
APPLICANT’S PATENT AGENT