US2225731A - Broaching machine - Google Patents

Description

Dec. 24, 1940. w. D. AVERILL BROACHING MACHINE filed March 21, 1958 4 Sheets-Sheet l ATTORNEY.

Dec. 24, 1940. w. D. AVERILL 2,225,731

BROACHING MACHINE Filed March 21, 1958 4 Sheets-Sheet 2 'IIKO-HP ATTORNEY.

Dec. 24, 1940. w p AVERILL 2,225,731

BROAGI'IING MACHINE Filed March 21, 1938 4 Sheets-Sheet 3 ATTORNEY.

Dec. 24, 1940. V w. D. AVERILL 2,225,731

BROACHING MACHINE Filed March 21, 1958 4 Sheets-Sheet 4 I IN VEN TOR. m Maw/*7 .0 #rmu ATTORNEY.

Patented Dec. 24, 1940 UNITED STATES PATENT OFFICE BROACHING MACHINE Application March 21, 1938, Serial No. 197,044

18 Claims.

This invention relates to machine tools and more particularly to broaching machines.

One of the-objects of this invention is to provide an improved cycle of operation for a single ram broaching machine.

Another object of this invention is to provide a single ram broaching machine with improved means for simultaneously breaching a plurality of Work pieces.

A further object of this invention is to provide a broaching machine with automatic. means for unclamping and unloading awork piece.

An additional object of this invention is to provide an improved automatic cycle control mechanism having sequential interlocks for insuring that each step in the cycle is completed before the next movement begins.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings illustrative of one embodiment thereof, but itwill be understood that any modifications may be :made in the specific structural details within the scope 25 of the appended claims without departing from or exceeding the spirit of the invention.

Referring to the drawings'in which like reference numerals indicate like or similar parts:

Figure 1 is a side elevation of a portion of a broaching machine embodying the principles of this invention.

Figure 2 isa plan view partly in section of the machine shown in Figure 1, and as viewed on the line 22 of that figure.

Figure 3 is a detail vertical section through one of the work holders and showing the automatic ejector.

Figure 4 is a detail sectionof a portion of the control mechanism as viewed on the line 4-4 40 of Figure 1.

Figure 5 is a detail section on the line 5--5 of Figure 3.

Figure 6 is an enlarged plan view of the work holding mechanism.

Figure '7 is a detail section on the line 1-4 of Fi ure 6.

Figure 8 is a diagram of the hydraulic-control circuit.

Referring to Figures 1,2, and ,3 of the drawings, the reference numeral l0 indicates the Vertical column of a broaching machine, and this column is provided with V-guideways H and I2 for receiving a vertically reciprocable ram I3. The front of the ram is provided with a dovetailed guide M in which is adjustably mounted and clamped a broach holder I5, the broach holder having two sets of broaching teeth I6 and I1 parallelly mounted thereon for simultaneous operation on separate work pieces. The broaching tools may be secured to the holder l5 by clamping screws I8 threaded into the back of the tools, as more particularly shown in Figure 3.

The column I8 is provided with an integral knee IQ for supporting a work table 20. A work fixture 2| is secured to this table. The fixture is provided with two upstanding mandrels 22 and 23, and each mandrel, as shown in Figure 3, has a reduced "portion 24 which fits in a bore in the work fixture. The shoulder 25 of the mandrel rests on a wearing ring 26, the ring also supporting the work. Each mandrel has a rectangular slot 21 cut in the upper portion thereof in which is mounted a work clamping member 28. This member is supported on a pair of pins 29 which pass through elongated holes 30 whereby the member is free to move laterally a limited amount.

The work clamping member 28 has an arcuate slot 3| cut in one side for receiving a roller 32 which is rotatably supported on a pin 33. A clamp actuating rod 34 passes through the mandrel and has a wedge shaped head 35 which is adapted to engage the roller 32 for moving the clamping member radially into engagement with a work piece. These work fixtures are particularly adaptable for holding cylindrical work pieces, such as the piece 36, and these pieces are formed by rolling flat stock into cylindrical form and then welding the abutting ends. The broaching operation performed on these pieces consists in broaching or cutting off the excess metal atthe welded seam, as indicated by the reference numeral 3! in Figure 2.

A three point clamp is provided for each work piece comprising two angularly spaced abutments 38 and 39 which are fixed to the work fixture by clamping screws 40, as more particularly shown in Figure 7. These-pieces have arcuate surfaces against which theexterior surface of the work is forced by the clamping member 128 which engages-the inside surface of the work. When the clamping memmr 28 is released, a pair of spring pressed plungers 4| located in each abutment serves to move the work piece away from the abutments a predetermined amount thereby assisting in retracting the clamping member 28 for insertion of the next-work piece.

The operator loads the fixtures by hand, and then the rods 34 are moved downward by power means to clamp the work, the member 28 moving forward to thereby move the work forward 55 into engagement with the two fixed abutments carried by the fixture whereby the work is held by a three point support.

The rods 34 are actuated by power cylinders 42 which, as shown in Figure 1, are pivotally supported at 43 on the under side of table 20. Each cylinder has a piston 44 which is connected by a piston rod 45 to a centrally pivoted lever 46 which has its other end connected with the rod 34.

The cylinders are connected in parallel to a control valve 41. In other words, a channel 48 is connected to ports 49 and 50 located in the lower end of the respective cylinders, and a channel 5| is connected to ports 52 and 53 located in the upper end of the respective cylinders. The valve 4'l' has a pressure port 54 which is supplied with pressure fluid, such as compressed air, from a suitable source indicated by the reference nu meral 55. Thus, when the port 54 is connected to channel 48, the pistons 44 move up to clamp the work; and. when connected to the channel 5|, the pistons move down to release the work. The valve 47 is a rotary valve having an operating handle 56, which is connected by a link 51 to an oscillatable plate 56, carrying a pin 59 movable into the path of a dog 60 attached to the rim I3. The lever 56 also has a crank 6|, which is connected by a link 62, through a lost motion slot 63, to a pin 64 located in the. end of control lever 65 of a pilot valve 66. V

The lever 56 is mounted on the side of the knee, as shown in Figure 2, for movement by the operator in a counterclockwise direction, as viewed in Figure 8, to effect admission of compressed air to the clamping cylinders 42, and simultaneously to position the pin 59 in the path of the dog 60. Due to the lost motion connection at 63 with the pilot Valve control lever 65, the pilot valve will remain in its dash and dot position indicated b the reference numeral 65.

The broaching ram is assumed to be at the top of its stroke when the work is loaded and clamped. As the pistons 45 move upward to clamp the work, they release the pressure on opposite ends of an equalizer bar 61 pivotally connected at the center to aplunger E58,v whereby the plunger moves upward along with the pistons 45 under the urge of a spring 69. As the plunger 68 moves upward, it rotates a bell crank 10 in a counterclockwise direction. This crank has a third arm II in the end of which is mounted a spring pressed pin 12.

As the arm II moves counterclockwise, the pin engages a crank arm I3 integral with the lever 65 thereby rotating the lever 65 in a clockwise direction. This rotates the pilot valve into a position to connect the pressure port I4, which is supplied by a pump 15, to port I6, and simultaneously interconnects port TI to a reservoir port 18. Ports I6 and I! are connected by channels 15 and-80 to opposite ends of a reversing valve BI. Since the channel 19 is under pressure at this time, the plunger 82 of the reversing valve is shifted into its right hand position. This results in the pressure port 83 of the valve, which is supplied by a separate pump 84, being connected to port-85-whereby fluid will flow through the connected channel 86, and the central bore 81 in the piston rod 88, to the lower chamber 89 of ram cylinder 90. I The cylinder 90, as shown in'Figure 8, is formed within the slide I3 whereby the cylinder becomes the moving member and the piston 9|, contained within the cylinder, the fixed member. The upper end 92 of the cylinde'ris connected through a second passage 93 in the piston rod to channel 94 that leads to port 95 of a double check valve 96. This valve has a first spring pressed plunger 91 which is opened by the returning fluid, so that it may continue through port 98 and channel 99 to port I of the reversing valve. This port is connected by an annular groove IOI to an exhaust port I02, which in turn is connected by channel I03 to the reservoir I04. 1

It will now be evident that the operator throws the lever 56 to eifect clamping of the work, and after both work pieces have been properly clamped, a pilot valve is automatically operated to shift the reversing valve into a position to cause admission of fluid pressure to the ram operating cylinder in such a manner as to cause downward movement of the broaching ram.

After the broaching teeth pass by the work to complete the broaching operation, the ram continues its downward movement a suflicient amount to permit automatic work ejectors to engage the under side of the work pieces. One of these ejectors is shown in Figure 3 and comprises a hook shaped member I which is pivotally mounted on a pin I06 carried by the ram. The ejector I05 is continuously urged in a clockwise direction by a spring pressed plunger I01, its movement being limited by an adjustable set screw I08 located on the side of the pin I06 opposite the plunger I0'I.

As the ram moves down, the beveled face I09 on the lower end of the ejector I05 engages the side of the work and is thereby rotated in a counterclockwise direction so as to move past the work piece. As the broaching ram approaches the end of its stroke, the hook portion IIO snaps under the work piece in a position to raise the same upon upward movement of the ram.

As shown in Figure 5, the member I05 has two projecting lugs III and II2, and in order to insure that these will engage the under side of the work, the supporting ring is cut away to form two slots H3 and H4 into which the lugs III and H2 may enter. When the ram moves up, these lugs lift the work piece off of the mandrels and cause it to tip backward away from the rams so that it will fall into approximately the dash and dot outline position indicated by the reference numeral H5.

The downward movement of the ram is stopped by the dog 60 engaging the pin 59 thereby rotating the plate 58 in a counterclockwise direction, as viewed in Figure 8, and through the various linkage connections to valves 41 and 66, the air pressure is reversed in cylinders 42, and the pilot valve is operatively rotated counterclockwise to connect the pressure port I4 to port 11, and port 16 to exhaust port I8. This will cause fluid pressure to flow to the right hand end of the reversing valve shifting the plunger 82 into its left hand position thereby reversing the connections to the ram cylinder. At the same time, however, the fluid in channel 80 flows to the left end of a by-pass valve II6 shifting the plunger II! to the right against the compression of aspring IIB. An annular groove H9 in this valve interconnects ports I20 and IZI whereby the fluid pressure existing in the space I22 of a relief valve I23 is by-passed to reservoir through channel I24, interconnected ports I20 and I2I, and return line I25.

The pump 84 is continuously pumping fluid into the space I26 of relief valve I23 and this fluid is continuously acting on one end of the piston I2'I which is slidably mounted in the valve and normally held against movementby pressure in the space I22. But when. the pressure in this space is Icy-passed to reservoir, the piston I21 shifts to the right, and the-end of the piston rod 128 integral with the piston -I2I uncovers port I23, whereby the pump 84 is by-passed to reservoir through channel I03 which has a branch connection to port I29. Thus, although the reversing valve plunger 82 is shifted to the left, the supply pump 84 is by-passed to reservoir and the ram will stop.

As the air pressure in cylinders 42 move the pistons 44 downward to unclamp the work, they engage opposite ends of the equalizer .bar 61 moving plunger 88 downward against the compression of spring 69. This rotates the bell crank 16 in a clockwise direction.

The by-pass valve plungerI II has a lost motion connection I30 with the end I3I of the bell crank I0, but at this movement the lost motion has been taken up due-to the hydraulic shifting to the right. Therefore, when the bell crank I is rotated in a clockwise direction, it moves the plunger III to the left a suificient amount to close the port I2I. This will permit fiuid-inthe space I26 in valve I23 to leak through a groove I32 in plunger I21 intothe space I22 and since the end area of the piston 121 in space -I22 is greater than the opposite end area of the piston due to the fact that the piston rod I28 'is larger indiameter than the piston rod I33, the piston I21 will gradually move to the left to close port I29.

When the port I29 has finally closed, fluid pressure will build up in channel 99 opening -a second plunger I34 in valve 96, so that the same may continue to the upper end of the cylinder 90. The fluid in the lower end of the cylinder will return to reservoir through channel 96, interconnected ports 85 and I35 of the reversing valve, and return channel I03.

The double relief valve 96 insures that there will always be fluid in the upper end of cylinder 90 and thereby preventtheram from accidentally dropping.

The ram moves up, ejecting the work in the manner just described until a dog I36 engages a trip lever I31. This rotates a'valve I38 into a position to interconnect port I38 with port I46. The port I39 is connected by a channel I4I to channel 86 which at this time is connected to reservoir. The port I40 is connected'by a channel 142 to port I43 of the relief valve I23 whereby the fluid in. chamber I22 of the relief valve is by-passed to reservoir permitting the piston I32 to move toward the right and thereby open port I29 so that the delivery of pump 84 is by-passed to reservoir whereby upward movement of the ram stops.

The operator loads new work pieces in the work fixtures and the machine is ready to repeat the cycle. In doing this the dog I36 will start down with the ram and rotate the valve I38 into engagement with the second trip lever I44 thereby closing the, by-pass connection to reservoir from port I43 of the relief valve I23. This by-pass connection is previously closed at another point, however, in order that the relief valve might close so that the ram could. start its downward movement. This was accomplished when the reversing valve plunger 82 shifted to'the right because up until this time, the port 85 was connected to reservoir. When the reverse valve plunger 82 shifted :to-the right, the circuit was closed .so that the necessary pressure could build upin thespace I22 and thereby shift the piston I21 to the left.

For emergency stopping, the channel I24 is provided with-a branch connection I45 to reservoir in which is a valve I46 which is adapted to be rotated by either the manually operable handle I41, or the foot pedal I48 which is connected to the valve lever I49 by a link I56. When this valve is rotated in a clockwise direction, the branch I45 is connected to reservoir thus relieving the pressure in the chamber I22 of valve I23 causing the port I29 to open.

There has thus been provided an improved broaching machine which has an improved control circuit for simultaneously broaching a plurality of work pieces together with automatic ejecting means, and sequential interlocks to insure that each successive step in the cycle has been completed before the next motion is undertaken.

What is claimed is:

1. In a broaching machine having a work support and a broaching ram movable relative to said support, the combination of a work receiving mandrel mounted on said work support with its axis parallel to the direction of movement of said ram, means for clamping the work, means for unclamping the work during movement of the ram in one direction, and means carried by the ram for lifting the work piece off the mandrel during ram movement in an opposite direction.

2. In a broaching machine having a work support and a power operable broaching ram movable relative to said support, manually operable means for clamping a work piece to said support and causing a feeding movement of said ram, automatically operable means for stopping the ram and unclamping the work at the end of the broaching stroke, and means carried by the ram for automatically ejecting a work piece during its return stroke.

3. A broaching machine having a work support, a plurality of work receiving mandrels mounted on said support, a broaching ram, a plurality of broaching tools carried by the ram, means to move the ram to effect simultaneous broaching of the several work pieces, means to return the ram, and means carried by the ram and effective during its return stroke for removing the several work pieces from the respective mandrels.

4. In a broaching machine having a work support, the combination of a broaching ram movablein one direction past said support for effecting abroaching operation, and work removing means carried by the end of the broaching ram .for engaging and removing a work piece from the support during movement of said ram in an opposite direction.

'5. In a broaching machine having .a work support and a broaching ram movable relative to said support, the combination of means for clamping a plurality of work pieces on the work support for simultaneous broaching, power operable means for effecting a broaching stroke of said ram, a plurality of broaching tools carried thereby for engagement with the respective work pieces, trip operable means for stopping the downward movement of the ram and causing automatic unclamping of the work, and means responsive 'tosaid unclamping means for initiating return movement of the ram.

:6. In a machine tool having a work support, a broaching ram, a plurality of parallelly arranged broaching tools on said ram, the, combination of a plurality of work receivers on the work support, individual power operated clamping means associated with each receiver," power operable means for reciprocatingsaid ram, including a reversing mechanism, trip operable means for releasing said power operated work clamps at the end of the broaching stroke, and interlocking means for preventing said reversing mechanism from becoming effective until all of said power operated clamps havebeen released.

7. In a broaching machine having a work support and a broaching ram, the combination of fluid operable means for reciprocating said ram, including a supply channel, a pump, a pressure closed relief valve connecting said pump to said channel, and trip operable means for releasing the pressure in said valve to stop the movement of the ram.

8. In a broaching machine having a work support and a broaching ram, the combination of fluid operable means for reciprocating said ram, including a supply channel connected to said ram, a pump, a pressure closed relief valve for maintaining the pump operatively connected to said channel, trip operable means for by-passing the holding pressure in saidrelief valve for stopping the ram at the end of its stroke, and additional means for by-passing the holding pressure at any time for emergency stopping, including a manually operable lever and a pedal operable lever.

9. In a broaching machine having a work support and a broaching ram, the combination of fluid operable means for shifting said ram, including a reversing valve, a relief valve connecting said pump to the reversing valve, means to establish a holding pressure in said relief valve for maintaining the same closed, a by-pass valve for said holding pressure, fiuid operable means for shifting said reversing valve, and said by-pass valve, whereby the reversing valve will be positioned to change the movement of the ram, but the pump will be by-passed to reservoir, a work clamping means carried by the work support, and means operable by said work clamping means upon movement to a work releasing position to close said by-pass valve and thereby initiate movement of the ram.

10. In a machine tool having a work support and a broaching ram, the combination of fluid operable means for reciprocating said ram, including a pilot valve for determining the direction of ram movement, a work clamping member carried by the work support having a first position for clamping the work, and a second position for unclamping the work, and means responsive to the positioning of said member reacting on the pilot valve for determining the position of said pilot valve.

11. A control mechanism for a broaching machine or the like embodying a plurality of work clamping devices and a ram member mounted for translation with respect to said devices, said mechanism including multiple independently shiftable work clamping members, a power transmitting member variably positionable by difierent movements of the work clamping members, means providing a pilot control circuit including a shiftable valve, operative connections between-the clamp controlled member and said valve, a main actuating circuit including an effective pressure determining valve, an operative connection between the pilot valve and said main circuit control valve whereby the pilot circuit will differently react on the valve dependent on the position of the pilot valve, and a lost motion connection between the clamp controlled member and said valve whereby said valve may be actuated with or relative to the controlled member in diiferent clamp determined positions thereof.

12. A control mechanism for a broaching machine or the like embodying a plurality of work clamping devices and a ram member mounted for translation with respect to said devices, said mechanism including multiple independently shiftable work clamping members, a power transmitting member variably positionable by different movements of the work clamping members, means providing a pilot control circuit including a shiftable valve, operative connections between the clamp controlled member and said valve, a main actuating circuit including an effective pressure determining valve, an operative connection between the pilot valve and said main circuit control valve whereby the pilot circuit will differently react on the valve dependent on the position of the pilot valve, a lost motion connection between the clamp controlled member and said valve whereby said valve may be actuated with or relative to the controlled member in different clamp determined positions thereof, valve means for determining the operative position of the work clamps and linkage interconnecting said valve means and the pilot valve for effecting simultaneous actuation thereof.

13, A control mechanism for a broaching machine or the like embodying a plurality of work clamping devices and a ram member mounted for translation with respect to said devices, said mechanism including multiple independently shiftable work clamping members, a power transmitting member variably positionable by different movements of the work clamping members, means providing a pilot control circuit including a shiftable valve, operative connections between the clamp controlled member and said valve, a main actuating circuit including an efl ective pressure determining valve, an operative connection between the pilot valve and said main circuit control valve whereby the pilot circuit will differently react on the valve dependent on the position of the pilot valve, a lost motion connection between the clamp controlled member and said valve whereby said valve may be actuated with or relative to the controlled member in different clamp determined positions thereof, valve means for determining the operative position of the work clamps and linkage interconnecting said valve means and the pilot valve for effecting simultaneous actuation thereof, and a yielding connection intervening the pilot valve and the clamp actuated member whereby the valve may be positioned by or with respect to said member.

14. A control mechanism for a broaching machine or the like embodying a plurality of work clamping devices and a ram member mounted for translation with respect to said devices, said mechanism including multiple independently shiftable work clamping members, a power transmitting member variably positionable by different movements of the work clamping members, means providing a pilot control circuit including a shiftable valve, operative connections between the clamp controlled member and said valve, a main actuating circuit including an effective pressure determining valve, an operative connection between the pilot valve and said main circuit control valve whereby the pilot circuit will differently react on the valve dependent on the position or the pilot valve, a lost motion connection between the clamp controlled member and said valve whereby said valve may be actuated with or relative to the controlled member in difierent clamp determined positions thereof, valve means for determining the operative position of the work clamps and linkage interconnecting said valve means and the pilot valve for effecting simultaneous actuation thereof, a yielding connection intervening the pilot valve and the clamp actuated member whereby the valve may be positioned by or with respect to said member, and interengaging means carried respectively by the ram and the work clamp valve for efiecting definite positioning of the clamp and pilot valves in opposition to the reaction of said yielding connection.

15. A control mechanism for a broach or like machine tool which includes a hydraulically translatable ram member, means for supporting Work in opposition to the ram member and releasable clamp mechanism for maintaining work pieces in position, said control mechanism including a first hydraulic actuating circuit for the ram having serially arranged power conditioning and reversing valves, a second hydraulic control circuit including a variably positionable pilot valve intervening the fluid pressure source and the reversing valve and reacting thereon for power positioning thereof, and valve means including elements actuable by positioning of the pilot valve and elements independent of the positioning thereof, each reacting on the circuit condition determining valve to determine the flow reaction of the hydraulic power circuit on the translatable ram for a given positioning of the pilot and reversing valves.

16. A control mechanism for a broach or like 40]machine tool which includes a hydraulically translatable ram member, means for supporting Work in opposition to the ram member and releasable clamp mechanism for maintaining work pieces in position, Said control mechanism including a first hydraulic actuating circuit for the ram having serially arranged power conditioning and reversing valves, a second hydraulic control circuit including a variably positionable pilot valve intervening the fluid pressure source and the reversing valve and reacting thereon for power positioning thereof, valve means including elements actuable by positioning of the pilot valve and elements independent of the positioning thereof, each reacting on the circuit condition determining valve to determine the flow reaction of the hydraulic power circuit on the translatable ram for a given positioning of the pilot and reversing valves, an auxiliary control mechanism for determining the operative and inoperative position of the work clamps, and operative connections between the work clamp mechanism, the pilot valve and at least one of said condition determining elements for variably positioning said two last-named parts dependent on the operapower positioning thereof, valve means including elements actuable by positioning of the pilot valve and elements independent of the positioning thereof, each reacting on the circuit condition determining valve to determine the fiow reaction of the hydraulic power circuit on the translatable ram for a given positioning of the pilot and reversing valves, an auxiliary control mechanism for determining the operative and inoperative position of the work clamps, operative connections between the work clamp mechanism, the pilot valve and at least one of said condition determining elements for variably positioning said two last-named parts dependent on the operative position of the work clamp elements and their controls, a first series of cooperating members coupled with the ram and clamp controls for actuation of the aforementioned parts upon movement of the ram, and additional independent cooperating means on the ram and one of said circuit controlling elements for ef- 1;.

fecting independent actuation of said element during movement of the ram substantially as and for the purpose described.

18. In a machine of the character described, the combination with a reciprocable broach carrying ram, of means for supporting work in opposition to the ram including clamping members and actuation controlling means therefor, a power circuit for determining reciprocation of the ram including a source of power, a circuit conditioning Valve and a serially arranged reversing valve intervening the source of power and the ram, a valve element coupled with and reactable on the conditioning valve, a pilot circuit having branches coupled with the reversing valve and the element, a pilot valve for determining the effective couplings of the circuit with said lastnamed parts and operative connections including resilient actuators and lost motion devices intervening the clamp control mechanism, the pilot valve and said element, whereby shifting of the parts into clamped releasing position conditions the ram actuating circuit for reversal of the ram but interrupts actuation thereof and 1 continued movement of the clamp control mechanisms reconditions the power circuit to effect subsequent reverse movement of the ram substantially as described.

WILLIAM D. AVERILL.

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