Drilling apparatus

Claim 2

A drilling apparatus for drilling one or more holes in a workpiece comprising, a frame, a drill mechanism including a drill bit supported on said frame for movement relative to said workpiece, drive means for rotating and for moving said drill bit axially toward and away from said workpiece, control means operably associated with said drive means for moving said drill bit at least at one predetermined rapid-feed rate prior to engagement with said workpiece and at a predetermined, relatively slower, substantially constant cutting feed rate during engagement with said workpiece, sensing means for determining the axial feed rate of said drill bit during cutting coacting engagement with said workpiece, feedback means operably associated with said sensing means being adapted to produce an output signal related to said predetermined cutting feed rate and the actual feed rate of said drill bit during said cutting coacting engagement with said workpiece, and said control means arranged to actuate said drive means in response to said outpuT signal of said feedback means to move and maintain said drill bit at said predetermined, substantially constant, cutting feed rate.

Claim 3

In a drilling apparatus in accordance with claim 1, wherein said drive means includes, a fluid pressure motive means adapted for moving said drill bit with more than one predetermined axial feed rate toward and in cutting coaction with said workpiece and for retracting said bit at a predetermined rate away from said workpiece.

Claim 4

In a drilling apparatus in accordance with claim 2, wherein said motive means includes, a reciprocal fluid pressure motor unit, and control valve means for regulating the flow of fluid pressure to said motor unit from a supply source.

Claim 5

In a drilling apparatus in accordance with claim 3, including electrical control means operably associated with said control valve means for controlling reciprocal movement of said motor unit in response to the rate of rotation of said drill bit.

Claim 6

In a drilling apparatus in accordance with claim 1, wherein said control means includes, first switch means operably associated with said drive means for moving said drill bit axially toward said workpiece at a relatively high predetermined rate of speed.

Claim 7

In a drilling apparatus in accordance with claim 5, wherein said control means includes, second switch means operably associated with said drive means for automatically reducing said predetermined speed rate to a relatively lower predetermined rate of axial speed and at a predetermined distance from said workpiece.

Claim 8

In a drilling apparatus in accordance with claim 1, including depth control means operably associated with said drive means for automatically retracting said drill bit from cutting coaction with said workpiece after forward movement of said bit to a predetermined depth in said workpiece.

Claim 9

In a drilling apparatus in accordance with claim 1, including service means operably associated with said drill mechanism for automatically delivering a cooling and/or lubricating media to said drill bit in response to movement thereof toward and away from said workpiece.

Claim 10

A control system including a servomechanism for controlling movement of a drill mechanism with respect to a workpiece comprising, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating a drill mechanism, said primary control circuit including a first circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate, a first switching means operably connected to said drill mechanism, said switching means sequentially electrically connecting said first and second circuits to said servomechanism, a third circuit electrically connected to said servomechanism, a second switching means electrically connected to said third circuit to energize said third circuit for moving said drill mechanism at still another forward feed rate, feedback means operably connected to said drill mechanism and electrically connected to said third circuit and said switching means, and said feedback means being responsive to the feed rate of said drill mechanism to automatically actuate said switching means and to energize said third circuit to maintain a relatively constant forward feed rate of said drill mechanism.

Claim 11

A control system including a servomechanism for controlling movement of a drill mechanism with respect to a workpiece comprising, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating a drill mechanism, said primary control circuit including a first circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate, a first switching means operably connected to said drill mechanism, said switching means sequentially electrically connecting said first and second circuits to said servomechanism, a third circuit electrically connected to said servomechanism, a second switching means electrically connected to said third circuit to energize said third circuit for moving said drill mechanism at still another forward feed rate, feedback means operably connected to said drill mechanism and electrically connected to said third circuit and said switching means, and said feedback means being responsive to the feed rate of said drill mechanism to automatically actuate said switching means and to energize said third circuit to maintain a relatively constant forward feed rate of said drill mechanism.

Claim 12

A control system including a servomechanism for controlling movement of a drill mechanism with respect to a workpiece comprising, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating a drill mechanism, said primary control circuit including a first ciRcuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate, a first switching means operably connected to said drill mechanism, said switching means sequentially electrically connecting said first and second circuits to said servomechanism, a third circuit electrically connected to said servomechanism, a second switching means electrically connected to said third circuit to energize said third circuit for moving said drill mechanism at still another forward feed rate, a fourth circuit operably connected to said first, second and third circuits, and electrically connected to said switching means for predetermined deenergization of said first, second and third circuits, and retract signal means electrically connected with said fourth circuit to provide a signal to energize said fourth circuit when the rotational speed of said drill mechanism changes relative to a predetermined speed.

Claim 13

A control system including a servomechanism for controlling movement of a drill mechanism with respect to a workpiece comprising, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating a drill mechanism, said primary control circuit including a first ciRcuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate, a first switching means operably connected to said drill mechanism, said switching means sequentially electrically connecting said first and second circuits to said servomechanism, a third circuit electrically connected to said servomechanism, a second switching means electrically connected to said third circuit to energize said third circuit for moving said drill mechanism at still another forward feed rate, a fourth circuit operably connected to said first, second and third circuits, and electrically connected to said switching means for predetermined deenergization of said first, second and third circuits, and retract signal means electrically connected with said fourth circuit to provide a signal to energize said fourth circuit when the rotational speed of said drill mechanism changes relative to a predetermined speed.

Claim 14

A control system including a servomechanism for controlling movement of a drill mechanism with respect to a workpiece comprising, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating a drill mechanism, said primary control circuit including, a first circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate, a first switching means operably connected to said drill mechanism, said switching means sequentially electrically connecting said first and second circuits to said servomechanism, and speed-responsive retraction means operably connected to said drill mechanism and electrically connected to said primary circuit to move said drill mechanism away from a workpiece.

Claim 15

A control system including a servomechanism for controlling movement of a drill mechanism with respect to a workpiece comprising, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating a drill mechanism, said primary control circuit including, a first circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate, a first switching means operably connected to said drill mechanism, said switching means sequentially electrically connecting said first and second circuits to said servomechanism, and speed-responsive retraction means operably connected to said drill mechanism and electrically connected to said primary circuit to move said drill mechanism away from a workpiece.

Claim 16

A drilling apparatus in accordance with claim 1, including another sensing means operably associated with said drive means for retracting said drill bit from cutting coaction with said workpiece in response to reduction in the rate of rotation of said drill bit.

Claim 17

A drilling apparatus in accordance with claim 1, wherein said sensing means comprises a tachometer generator operably mounted on said drill mechanism for producing an output signal proportional to the axial speed of said drill bit.

Claim 18

A drilling apparatus in accordance with claim 12, wherein said another sensing means comprises a tachometer generator operably connected to said drill bit adapted to produce an output signal proportional to the rotational speed of said drill bit.

Claim 19

A drilling apparatus in accordance with claim 1, including pressure-responsive sensing means operably connected to said drill bit for sensing the axial pressure on said drill bit during cutting coaction with said workpiece, and said pressure-responsive sensing means including a switching device arranged to be actuated upon application of an axial pressure on said drill bit in excess of a predetermined pressure to retract said drill bit from said workpiece.

Claim 20

A drilling apparatus in accordance with claim 1, wherein said drill mechanism is pivotally mounted on said frame for pivotal movement of said drill bit about a generally horizontal axis.

Claim 21

A drilling apparatus in accordance with claim 1, wherein said control means include a servomechanism for controlling the movement of said drill mechanism with respect to said workpiece, a primary control circuit adapted to be connected to a source of electrical power, said servomechanism electrically connected with said primary control circuit for actuating said drill mechanism, said primary control circuit including a first circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at one feed rate, a second circuit electrically connected to said servomechanism for moving said drill mechanism in a forward direction at another feed rate relatively slower than said one feed rate, a first switching means operably connected to said drill mechanism, and said switching means sequentially electrically connecting said first and second circuits to said servomechanism.

Claim 22

A drilling apparatus in accordance with claim 17, wherein said servomechanism includes a current-responsive servo member, said servo member electrically connected to said primary control circuit, and said second circuit having a greater resistance than said first circuit.

Claim 23

A drilling apparatus in accordance with claim 17, including a third circuit electrically connected to said servomechanism, and a second switching means electrically connected to said third circuit to energize said third circuit for moving said drill mechanism forwardly at said predetermined cutting feed rate upon cutting coacting engagement of said drill bit with said workpiece.

Claim 24

A drilling apparatus in accordance with claim 19, wherein said feedback means is operably connected to said drill mechanism and electrically connected to said third circuit and said switching means, and said feedback means being responsive to automatically actuate said switching means and to energize said third circuit to maintain a relatively constant forward feed rate during cutting coaction of said drill bit with said workpiece.

Claim 25

A drilling apparatus in accordance with claim 19, including a fourth circuit operably connected to said first, second and third circuits, and electrically connected to said switching means for predetermined deenergization of said first, second and third circuits.

Claim 26

A drilling apparatus in accordance with claim 21, wherein said another sensing means being electrically connected with said fourth circuit to provide a signal output to energize said fourth circuit when the rotational speed of said drill mechanism changes relative to a predetermined speed.

Claim 27

A drilling apparatus in accordance with claim 1, including a support column extending from said frame, at least one drill head assembly depending from said support column for pivotal movement about a generally horizontal axis, said drill head assembly including a drill control mechanism, and said drill mechanism operably mounted on said drill head assembly being disposed for axial movement relative to said drill control mechanism toward and away from said workpiece.

Claim 28

A drilling apparatus in accordance with claim 23, including means for rotating said drill head assembly about a generally vertical axis, and means for rotating said workpiece on said frame.

Claim 29

A drilling apparatus in accordance with claim 23, including a pair of said drill head assemblies mounted on and depending from opposed sides of said support column each including a drill mechanism for independent or simultaneous drilling operation with respect to said workpiece or workpieces.