Variable speed percussion drilling machine

Claim 2

Variable speed percussion drilling machine comprising, in combination, drive shaft means; tool holder shaft means; transmission means connecting said drive shaft means with said tool holder shaft means, and having at least two stages for rotating said tool holder shaft means at different speeds; a striking mechanism having an operative position for reciprocating said tool holder shaft means in axial direction between two positions during rotation of the same, and an inoperative position in which said tool holder shaft means only rotates, said striking mechanism being urged into said operative position when said tool holder shaft means is pressed against a workpiece; first control means connected with said transmission means for shifting the same between said two stages; second control means connected with said striking mechanism for holding the same in said inoperative position when said tool holder shaft means is pressed against a workpiece; and common manually operated means connected with said first and second control means for simultaneously operating the same so that said tool holder shaft means rotates at different speeds while performing percussion drilling and rotary drilling operations.

Claim 3

Drilling machine as claimed in claim 1 wherein said manually operated means include a manually operated member and means interconnecting said first and second control means at the ratio 2 : 1 so that said first control means cyclically shift said transmission means twice between said two stages and said second control means shift said striking mechanism only once between said inoperative and operative positions during the same actuating movement of said manually operated member whereby said tool holder shaft means can be operated at two different speeds during a percussion drilling operation and also during a rotary drilling operation.

Claim 4

Drilling machine as claimed in claim 2 wherein said first and second control means include first and second rotary control members, respectively, for shifting said transmission means and for shifting said striking mechanism, respectively; and wherein said interconnecting means include meshing gear means selected so that said first rotary control member makes a half revolution when said second rotary control member makes a quarter revolution.

Claim 5

Drilling machine as claimed in claim 2 wherein said second control means include a prismatic second control member secured to said manually operated member eccentric to the axis of rotation of the same, and having a cross section bounded by a plurality of faces operatively connected with said striking mechanism for moving the same once between said inoperative and operative positions during each revolution of said manually operated member; wherein said interconnecting means include an interconnecting member rotatable about an axis; and wherein said first control means include a first control member eccentric to said axis of said interconnecting member and operatively connected with said transmission means for shifting the same twice between said two stages during each revolution of said manually operated member.

Claim 6

Drilling machine as claimed in claim 4 wherein said striking mechanism includes first displacement means secured to said tool holder shaft means and second stationary displacement means; wherein said tool holder shaft means is axially displaceable between a first position in which said first and second displacement means engage each other in said operative position of said striking mechanism, and a second position in which said first and second displacement means arE spaced and said striking mechanism is in said inoperative position; wherein said tool holder shaft means is biased to said first position and cooperates with said second control member to be shifted to, and held in said second position.

Claim 7

Drilling machine as claimed in claim 5 wherein said transmission means include a transmission shaft connected with said tool holder shaft for rotation, and being shiftable in axial direction between a first position and a second position, two different gears mounted on said transmission shaft and driven from said drive shaft, and coupling means on said transmission shaft for coupling the same with said two gears, respectively, in said first and second positions thereof so that said transmission shaft rotates at different speeds and wherein said transmission shaft has an annular groove engaged by said first control member so that said transmission shaft is shifted by the same between said first and second positions thereof.

Claim 8

Drilling machine as claimed in claim 4 wherein said interconnecting member is integral with said first and second control members and has a common axis with said manually operated member; wherein said first control member is a pin on said interconnecting member eccentric to said axis; and wherein said manually operated member, said second control member, said interconnecting member, and said pin turn together about said common axis.

Claim 9

Drilling machine as claimed in claim 4 wherein said interconnecting means include at least two meshing interconnecting gears; wherein one of said gears is secured to said manually operated member, and the other gear carries said first control member.

Claim 10

Drilling machine as claimed in claim 1 comprising a housing; wherein said tool holder shaft means is mounted in said housing for rotation, and for axial movement; wherein said striking mechanism includes first and second displacement means mounted on said shaft means and on said housing, respectively; wherein said manually operated means include a sleeve mounted on said housing for turning and axial movements; a spring connecting said sleeve with said tool holder shaft means; wherein said second control means include cam means connecting said sleeve with said housing so that when said sleeve is turned to a first position, said sleeve and tool holder shaft means are displaced to a first position in which said first and second displacement means are spaced but can be moved against the action of said spring to an engaging position in which said shaft is reciprocated, while when said sleeve is turned to a second position, said tool holder shaft is moved to a second position in which said first and second displacement means cannot engage each other so that said shaft rotates without reciprocating; wherein said transmission means includes a shifting member for shifting said transmission means between two stages; and wherein said first control means include other cam means connecting said sleeve with said shifting member for shifting said transmission during axial shifting of said tool holder shaft between positions for percussion drilling and rotary drilling at different speeds.

Claim 11

Drilling machine as claimed in claim 9 wherein said shifting member of said transmission means is a transmission shaft mounted in said housing for axial movement; wherein said transmission means includes spring means urging said transmission shaft axially in one direction; wherein said sleeve has a collar having said other cam means and being engaged by said transmission shaft under the action of said spring so that turning of said sleeve causes axial displacement of said transmission shaft; wherein said transmission means comprises a coupling means fixed to said transmission shaft, and two gears driven from said drive shaft means and being respectively coupled by said coupling means with said transmission shaft in axially displaced positions of said transmission shaft; and gear means connecting said transmission shaft with said tool holder Shaft means.

Claim 12

Drilling machine as claimed in claim 9 wherein said shifting member is a transmission shaft mounted in said housing for axial movement; wherein said sleeve has a collar including an axially curved cam plate; wherein said transmission shaft has an annular groove engaged by said cam plate so that turning of said sleeve causes axial displacement of said transmission shaft; wherein said transmission means comprises a coupling means fixed to said transmission shaft, and two gears driven from said drive shaft means and being respectively coupled by said coupling means with said transmission shaft in axially displaced positions of said transmission shaft; and gear means connecting said transmission shaft with said tool holder shaft means.

Claim 13

Drilling machine as claimed in claim 1 comprising a housing; wherein said manually operated means include a sleeve rotatable and axially movable on said housing; wherein said first control means include circumferential axially effective first actuating cam means on said sleeve for shifting said transmission means between said two stages; and wherein said second control means include circumferential axially effective second actuating cam means on said sleeve for moving said striking mechanism between said inoperative and operative positions.