US2190067A - Broaching machine - Google Patents

Description

w. A. HART 2,190,067

BROACHING MACHINE Feb. 13, 1940.

Filed Sept. 28, 1935 2 Sheets-Sheet 1 INVENTOR. lVz'ZZz'a /7, fiarit A TTORNEYS BROAGHING MACHINE Filed Sept 28, 1935 2 Sheets-Sheet 2 h zZZz'd W f7. f/ari ATTORNEYS.

INVENTOR.

Patented Feb. 13, 1940 uir PATENT OFFlCE BROACHIN G MACHINE Michigan Application September 28, 1935, Serial No. 42,619

' 1 Claim. (01. 90-43) Thepresent invention relates to metal working machines, and more particularly to improved mechanism for automatically moving the cutting I and work supporting elements of such machines.

It isan object of the present invention to provide a metal working'machine embodying improved means for effecting relative reciprocatory motion between a tool head and Work support- 10 ing table.

It is also an object of the present invention to provide a fluid pressure operated cylinder for use.

in metal working machines and the like,'and particularly adapted to impart a reciprocatory 15 motion to a tool head.

It is also an object of the present invention to provide a cylinder of the lastmentioned type, embodying a stationary piston and a movable casing therefor, for supporting a tool head, in

20 which the fluid pressure intake and exhaust lines may all be connected to thepiston rod.

It is also an object of thepresent invention to provide a cylinder of the last mentioned type, in which the movable casing is free of fluid pres- 25 sure connections.

It is also an object'of the present invention to provide a fluid pressure operatedcylinder of the above mentioned type in which the intake and exhaust lines may both be connected at the same 30 end of the piston structure.

It is also an object of the present invention to provide a fluid pressure operated cylinder embodying a two-passagepiston rod, constructed to accommodate fluid pressure intake and exhaust 35 lines and in which one of the passages communicate with the interiorof the piston casing on one side of the piston, and the other passage communicates with the interior of thecasing on the other side of the piston.

40 It, is also an object of the present invention to provide a fluid pressure operated cylinder embodying a movable casing and a stationary piston, in which the piston is constructed to provide two concentric passages, one of which com- 45. municates with one side of the piston head and the other of which communicates with the other side of the piston head.

It is also an object of the present invention to provide a metal working machine embodying a 50 pivotally supported work table, and automatic means to pivot the table from a cutting position to a loading position.

It is a further object of the present. invention to provide a metal working machine of the last s mentioned type in which the pivotal movements or" the work table are controlled in accordance with the movements of the machine cutting tool.

It is a further object of the present invention to generally improve and simplify metal Working machines, particularly those constructed to 0p- 5 erate broaching tools, and to provide an automatic machine which is simple in construction, economical of manufacture, and accurate and positive in operation.

Other objects of the present invention appear in the following description and in the appended claim.

In the drawings, throughout which corresponding reference characters are used to designate corresponding parts:

Fig. 1 is a view in perspective of a broaching machine embodying a fluid pressure operated cylinder constructed in accordance with the present invention; l

Fig.2 is a view in vertical section of a fluid pressure operated cylinder embodying the, present invention;

Fig. 3is a view in vertical section of illustrative fluid pressure connections to the piston. rod of the cylinder shown in Fig. 2;

Fig. 41s a View in horizontal section taken along the line 4-4 of Fig. 1;. and

Fig.5 is a view inside elevation of a broaching machine embodying a pivoted work table in accordance with the present invention.

As will be understood, metal working machines, such for example as automaticbroachin-g machines, compromise in general a. table for supporting the work to be machinedor broached, a corresponding support for a cutting tool, and means to impart relativemotion to the work piece and the cutting tool. In certain instances, the work piece is stationarily supported during a cutting movement and the cutting tool is reciprocated withrespect thereto. Alternatively, the cutting tool may be stationarily supported and the work piece reciprocated with respect thereto.

In the practice of both of these alternative arrangements, it has become customary to uti- 45 lize fluid pressure operated mechanism to provide the relative motion between the work piece and the outtingtool, and an important feature of the presentinvention is the provision of an improved construction of fluid pressure operated cylinder for effecting 'suchautornatic relative movement.

In the form illustrated, Y the improved fluid pressure operated cylinder of the present invention, comprises generally a casing within which 5 a piston is slidably supported and to which a piston rod is connected. Preferably, and as illus trated, the piston rod is stationarily supported and in operation, the casing reciprocates with respect to the piston head, the cutting tool being supported on the exterior of the casing.

To effect movement of the casing in one direction, fluid is introduced into the casing on one side of the piston and is exhausted from the casing on the other side of the piston. To produce an opposite direction of casing movement, a reverse transfer of fluid is effected.

In the form illustrated, the piston rod consists of two concentrically formed conduits, corresponding ends of which are fixed in the piston head and to a stationary support respectively. The inner conduit registers with a central opening cut through the piston head, and thus communicates with the interior of the casing on one side of the piston head. The outer conduit is provided with peripheral openings adjacent the point at which it is connected to the piston head, and thus communicates with the interior of the casing on the opposite side of the piston head. The piston rod conduits may be selectively dimensioned to produce any desired relation between the rates of travel of the casing in the respective directions.

The intake and exhaust lines may be connected to the piston rod in various ways. Preferably, and as illustrated, the intake and exhaust lines lead to the stationary piston rod support, and are connected to the piston rod conduits through cross passages formed in such support.

As will be understood, the feature of connecting the intake and exhaust lines to the stationary portions of the cylinder eliminates the necessity of flexible supply lines, and thus materially simplifies the construction. It also avoids the neces sity of connecting fluid lines into the casing. Since the connections to the casing portions on the two sides of the pistons are arranged within the single piston rod, such rod need extendonly on one side of the piston head, and provision is required for passing such piston rod through only one end of the casing. With this arrangement, accordingly, packing mechanism is required at only one point in the unit.

In the use of the improved cylinder of the present invention, particularly in connection with automatic broaching machines, the complete travel cycle of the cylinder casing is preferably automatic; that is, after having been started in motion, it travels to one limit of travel, is automatically reversed, travels to an opposite limit of travel and is again automatically reversed. The automatic reversing mechanism may be arranged in various ways. A preferred arrangement for accomplishing this is disclosed in the co-pending application of Richard A. Thompson, Serial No. 35,693, filed August '7, 1935, and assigned to the same assignee as the present application. As disclosed in that application, suitable reversing valve mechanism is provided, and arranged for movement from a position corresponding to one direction of flow, to a position corresponding to an opposite direction of fiow,asthe casing approaches opposite limits of travel. A reversing movement of the valve reverses the connection of the cylinder supply line to a source of pressure and an exhaust line.

To facilitate the insertion and removal or work, and ensure that the cutting tool shall not engage the work during a return movement of the former, it has been found desirable to provide means to withdraw the work during such return movement,

and a further feature of the present invention is the provision of an improved, pivotally supported work table, in combination with automatic means to swing the table between loading and cutting positions in accordance with the movements of the cutting tool. The illustrated arrangement is such that at the completion of a cutting movement, the work table is automatically swung to a loading position, at which it remains throughout the return movement of the cutting tool. At the completion of the return movement, and the beginning of a new cutting movement, the work table is automatically swung to a cutting position, in which it remains throughout the cutting movement. Preferably, and as illustrated, the actuating mechanism for the work table comprises a fluid. pressure cylinder, the connections to which are reversed at the above mentioned limits of travel by a suitable reversing control valve which responds to the position of the cutting tool.

Referring to Figs. 1 through 4 of the drawings, an illustrative machine with which the improved cylinder of the present invention may be used, comprises generally the supporting frame Ill, the vertical forward face of which is recessed to accommodate the cylinder mechanism designated generally l2, and the lower forward portion I4 of which is horizontally disposed to provide a suitable table upon which the work to be broached or machined (not shown) may be positioned. A preferred form of work table is disclosed in Fig. 5 and is described below. The cylinder mechanism I2 is provided with the laterally extending rail sections [6, which are slidably supported against the face of the frame H] by the guides I8. Guides 18 are secured to frame If] by studs 20. The forward face of the cylinder mechanism I2 is adapted to form a support for tool carriage 22, which is secured thereto by the countersunk studs 24. Cutting tool 26 is fitted in a longitudinal recess formed in carriage 22 and is secured therein by the countersunk studs 30.

As best shown in Figs. 2 and 4, cylinder mechanism l2 comprises the outer hollow cylindrical sleeve 32, within which the hollow casing 34 is relatively tightly fitted. The lower ends of sleeve 32 and casing 34 are closed by the plate 36, which is secured to casing 32 by studs 38. The upper ends of sleeve 32 and easing 3d are closed by collar 49, retaining rings 42 and 44, and by the piston rod designated generally 46. Collar 40 is secured to sleeve 32 by studs 48. Retaining ring 44, which is provided with a central aperture dimensioned to slidably receive piston rod 46, is press fitted within collar 40 and is supported against the annular shoulder 50 formed near the lower end thereof. Retaining ring 42, provided with a correspondingly dimensioned central aperture to receive piston rod 46, is press fitted into the upper end of collar 40 and is supported against the annular shoulder 52 formed in ,the latter. A suitable packing gland 54 is interposed between rings 42 and 44 to prevent the escape of fluid to the exterior of the cylinder.

Piston 46 comprises the two concentric hollow conduits 56 and 58. The lower end of conduit 56 is externally threaded, and is threaded into the upper end of piston head 69. Theupper end of conduit 56, as best shown in Fig. 3, is threaded into the stationary support 62, which may form a part of the machine frame 10. The upper and lower ends of the inner sleeve 58 are correspondingly externally threaded, and are threaded into support 62 and piston head 60,

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aieoper respectively. As will be understood, piston head 60 is slidably supported within casing --34, and

may, if desired; be provided with a plurality municate with the fluid supply lines 10 and 12, through the cross passages 14 and "I6 formed in support62. I

The boss T8 formed on the lower end of plate 36 is of substantially the same diameter as the inner conduit 58 and is in axial alignment therewith. At the upper limit of the stroke of oasing 34, boss 18 enters the lower end of conduit 58 and forms a fluid cushion for casing 34. A corresponding cushion is provided at the lower limit of travel of casing 34 by sleeve 80 which surrounds the outer conduit 56, and is disposed to enter a cooperating area 82 provided by th formation of the lower end of collar 46.

With reference to the operation of the cylinder mechanism as a whole, it will be understood that fluid introduced under pressure through intake line I0, circulates through the space between conduits 56 and 58, through the openings 66, and into the upper portion of casing 34. This action develops a pressure tending to force casing 34 upwardly. In response to this movement, the fluid which normally occupies the lower portion of casing 34 is forced therefrom through conduit 58 and out through the line 72. To effect I a downward movement of cylinder mechanism I2, fluid is introduced through line 12, and circulates through conduit 58 into the lower portion of casing 34, forcing the latter downwardly. In response to this movement, the fluid previously introduced into the upper portion of casing 34 is forced outwardly through opening 66, through the space between conduits .56 and 56 and out through line I0. It will beunderstood ber respectively, is disclosed in the above identified co-pending application of the present applicant.

Referring now to Fig. 5, work piece I06 and a usual rest I08 therefor are removably secured to the upper surface IIO of work table H2 by the illustrative clamping mechanism II4. Clamping mechanism II4 maybe of any suitable type and as illustrated comprises the clamp II6, pivotally secured by pin H8 to a support I20 which may be formed integrallywith work table H2. The eccentric I22 may be rotated by arm I24 to force clamp II'6 tightly into engagement with work piece I06.

Work table I I2 is pivotally supported on shaft I26 to the main supporting frame I0, and is adapted to be automatically swung between the full line and dotted line positions by the fluid {pressure mechainism designated "generally 428. In the run line position,' the upper flat surrace I-t0 of table Hrbfears against the shoulder I-30 formed-in frameJ-D; The tool 26, in passing across the workpiece 166, tends to rotatetable II 2 in a counterclockwise direction, as viewed in Fig. 5, the shaft I26 being-prefeiablylocated in offset relation to the pathiofmo'vementof tool -26. The force thus applied by the topics positively maintains table 2in the cutting-posi- I tion. In the full line position, a willbe understood, table I I2 holds workpiece HJG in cutting position with respectto cutting tool 26. Inthe dotted line or loading position of table I", work piece 106 is swung out of the path of cutting tool-26, and is not engaged thereby during its return movement. The movement of table I I! to the loading position, in addition to avoiding engagement between the cutting tool and the work piece during the return movement of the former, also facilitates the removal of the completed work piece I06 and the insertion of a new work piece.

The fluid pressure mechanism I28 may be constructed in various ways. As illustrated, it comprises a piston I32, slidably received within the casing I34, and pivotally connected to work table Il2 through the piston rod I36. Casing I34 is pivotally supported to frame I04 by shaft I38, and is provided with the side openings I40 and I42, into which the ends of the flexible supply lines I44 and I46 respectively are secured.

The other ends of supply lines I44 and I46 are connected to a suitable conventional reversing valve I48, the actuating arm I50 of which is subject to control by a lower cam I52,.which moves with tool 26, as Well as by an upper cam I54, which also moves with tool 26, and is disposed to engage a rocker arm I56. Rocker arm I56 is connected to arm I50 through push rod I58.

It will be understood that in one position, valve I48 connects line I46 to a source of fluid pressure illustrated as pump I60, and connects line I44 to a suitable exhaust chamber (not shown) through line I62; and that in a reverse position it connects line I44 to pump I60 and connects line I46 to the exhaust chamber.

With reference to the operation of the unit as a whole, the parts are shown in the positions occupied when in readiness for a cutting move ment of tool 26. In thesepositions, cam I54 retains the valve actuating arm I50 in the illustrated position, in which line I44 is connected to pump I60. These connections forcibly retain piston I42 in the upper illustrated position within cylinder I34, and force work table II2 to the full line or cutting position.

This positioning of the part obtains until the completion of a cutting movement of tool 26, at which time cam I52 engages valve arm I50,

rotating it in a clockwise direction to a-position in which the valve connections are reversed. With the reversed connections, line I46 is connected to pump I60 and piston I32 is accordingly forced to an opposite position in cylinder I34 and in the course of this movement rotates work table I I2 around shaft I26 to the loading position shown in dotted lines, in which work piece I06 is out of the path of cutting tool 26. This positioning of the parts obtains until, at the completion of a return movement, cam I54 again engages arm I56 and moves valve arm I50 to the illustrated position. At this time work table I I2 is again swung in a counter-clockwise direction to the cutting position.

Although specific embodiments ofthe present invention have been described, it will be vident that various modifications may be made in the low piston rods extending through the other end of said cylinder and connected to said piston for, supporting the same, the inner of said hollow rods defining the fluid inlet and outlet pas.- sage for one end of the cylinder and the space between the rods defining the fluid inlet and outlet passage for the other end of the cylinder, a stationary piston rod supporting head secured to the frame adjacent one end of the ways and having a pair of separate fluid passages formed therein, the inner rod being fixedly connected to and supported by said head in fluid communication with one of said head passages, and the outer rod being fixedly connected to and supported by said head with the space between said rods in fluid communication with the other head passage, and means on said cylinder intermediate its ends for supporting a broaching tool.

WILLIAM A. HART.

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