GB2025282A - Multi-purpose Machine Tool - Google Patents

Abstract

A multiple-purpose machine tool which is capable of performing both horizontal and vertical machining operations. The machine tool includes a bed which has three mounting feet so that it can be secured to an irregular work surface without impairment of the machine's performance, and has a movable carriage for positioning a workpiece placed thereon in proper orientation relative to various tool bits installable on the machine by the user. The carriage is moved by rotation of a handwheel-driven leadscrew which engages a floating nut slidably mounted in the carriage. The machine tool also includes a headstock and a tailstock, both of which are mounted to be removed from respective ends of the machine bed when the user changes from horizontal to vertical machining operations. <IMAGE>

Description

SPECIFICATION Multiple-purpose Machine Tool The present invention relates generally to machine tools, and more particularly to machine tools capable of performing a variety of machining operations.

With the greater availability of leisure time in our society, many persons have taken up pastimes involving the exercise of mechanical aptitude. For example, an individual may decide to use his or her free time to repair various household object such as lamps, furniture and appliances. The more serious-minded may engage in model railroad construction, gunmaking and camera repair. In order that these acivities may provide the utmost of enjoyment and satisfaction to the participant, it is imperative that proper tools be used. It cannot be disputed that what may at first appear to be a simple undertaking, can become a laborious and uninteresting chore if inadequate or improper tools are used for the job. However, acquiring a reserve of the various types of tools needed for most home projects can itself be an expensive and time-consuming, as well as a discouraging undertaking.

As a partial solution, a number of "multipurpose" tools have been made available so as to supposedly facilitate many types of home projects. However, these tools usually sacrifice an appreciable amount of quality in order that their cost can be maintained at attractive levels. In particular, in the area of precistion tools such as lathes, drilling and milling machines and grinders, it has not been common practice to combine such tools in a single unit, and especially in a single machine intended for use by non-professional or inexperienced operators. Yet, these tools are particularly useful for many construction and repair projects of interest to such persons.

A machine tool, capable of performing more than one machining function and intended for amateur use is disclosed in U.S. Patent No.

2,821,009. The machine disclose in the '009 patent includes a headstock which can be mounted to enable either horizontal or vertical machining to be performed on a workpiece.

However, as portions of this machine were styled in accordance with machines then known, its overall utility is somewhat limited.

For example, the machine disclosed in the '009 patent must be mounted on a truly flat work surface, or be properly shimmed at each of its four mounting feet, in order that its frame and bed not become distorted when the machine is bolted to the available work surface. As most home applications do not afford the luxury of a truly flat worktable surface, proper mounting may not always be feasible.

In addition, the tailstock of the machine disclosed in the '009 patent is not designed to be easily removable. This may well present a problem in the event that vertical machining operations are to be done on a relatively large workpiece, wherein the tailstock could interfere with proper positioning of the workpiece so as to make precision-type work thereon an impossibility.

Accordingly, it is an overall object of the present invention to overcome the above and other short-comings of prior art multiple-purpose machine tools.

It is another object of the present invention to provide a multiple-purpose machine tool which provides a high degree of precision and can be operated by both amateur and more-experienced operators.

It is still another object of the present invention to provide a machine tool capable of performing a variety of machining operations without sacrifice of precision and constructional integrity.

It is still another object of the present invention to provide a machine tool which can be set up on a variety of working surfaces without impairment of its operating capabilities.

It is a more particular object of the present invention to provide a machine tool which, in one configuration, includes a headstock and a tailstock confronting one another on a machine bed to enable horizontal machining operations and, in another configuration, has the headstock vertically aligned above the machine bed to provide for vertical machining operations with the tailstock either mounted or removed. Many other refinements to the various components of the machine result in a superior multiple-purpose machine tool capable of a wider variety of uses than other tools presently known.

In accordance with an illustrative embodiment demonstrating objects and features of the present invention, there is provided a multiple-purpose machine tool capable of performing a variety of machining operations. The tool comprises an elongated machine bed having a planar carriage surface extending longitudinally across at least a portion thereof, and dovetail ways at respective sides of the carriage surface. The bed also has three mounting feet arranged in a triangular configuration so as to restrain the bed from rocking move#ment and to maintain the carriage surface substantially planar when the bed is joined at its feet to a given working surface.

Further, a carriage leadscrew is rotatably mounted beneath the carriage surface in longitudinal alignment with the bed, the leadscrew being protectively shielded by the carriage surface from falling particles and the like.

A handwheel affixed to the leadscrew at one end of the bed has at least one groove extending across its outer edge which is longitudinally aligned with the carriage surface. A headstock is also provided for mounting at either the other end of the bed so that its spindle is aligned parallel to the longitudinal axis of the bed, or at a location above the bed wherein its spindle is aligned perpendicularly to the longitudinal bed axis.

Additionally, a tailstock having dovetail edges for slidably engaging the dovetail ways of the machine bed, includes a ram which is operatively aligned in confronting relationship with the headstock spindle when the headstock is mounted at the other end of the bed. The tailstock also includes a slot extending longitudinally across its top to receive a locking key plate for preventing rotation of the ram. One of the dovetail edges of the tailstock clears the leadscrew handwheel by passing through the handwheel groove when the tailstock is moved on or off of the machine bed.

The machine of the present invention also includes a carriage for sliding movement parallel to the longitudinal axis of the machine bed in response to rotation of the leadscrew, the carriage having a floating nut slidably mounted therein to engage the leadscrew beneath the carriage surface. A cross slide is constructed and arranged for smooth sliding movement across the top of the carriage, the cross slide including a feedscrew which threadably engages another floating nut slidably mounted in the carriage to move the cross slide transversely relative to the machine bed.

In the preferred embodiment, the machine tool of the present invention also includes an adjustable gib interposed between one of the dovetail edges on the tailstock and the confronting dovetail way on the machine bed.

Further, it is preferred that the headstock include one or more T-slots running longitudinally across the top thereof to provide for mounting of accessories thereon when the headstock is positioned above the machine bed for vertical machine operations.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully understood by reference to the following detailed description of the presently preferred but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawing, wherein:: Fig. 1 is a front perspective view of a representative machine tool of the present invention, showing the machine tool arranged for horizontal machining operations; Fig. 2 is a front perspective view of the machine tool of the present invention, showing the tool arranged for vertical machining operations; Fig. 3 is a fragmentary front elevational view, with parts broken away and shown in section, showing constructional details of a headstock mounted on a machine bed in accordance with the present invention; Fig. 4 is a right sectional elevational view of the mounted headstock, taken substantially along the line 4-4 of Fig. 3 and looking in the direction of the arrows;; Fig. 5 is a fragmentary top plan view, with parts broken away and shown in section, of the present machine tool, showing the configuration of its mounting feet and details of a floating nut mounted in the machine carriage according to the present invention; Fig. 6 is a fragmentary front elevational view, with parts broken away and shown in section, of a tailstock and showing details of a tailstock ram and a ram locking plate according to the present invention; Fig. 7 is a right side elevational view; partly in section, showing further details of the tailstock, taken substantially along the line 7-7 of Fig. 6 and looking in the direction of the arrows; Fig. 8 is a fragmentary top plan view of the mounted tailstock shown in Fig. 6; Fig. 9 is a fragmentary right side elevational view of the lower portion of the present machine tool, showing a dovetail edge on the tailstock aligned with a groove in the leadscrew handwheel according to the present invention; Fig. 10 is an enlarged fragmentary right side elevational detail view, with parts broken away and shown in section, showing a carriage with a floating nut in accordance with the present invention; Fig. 1 1 is a fragmentary front elevational view of a support assembly for the headstock for vertically reciprocating the headstock on a column in accordance with the present invention;; Fig. 12 is a fragmentary front elevational view of the present machine tool showing the headstock mounted to the support assembly of Fig. ii, and a motor drive unit for the headstock spindle; Fig. 13 is a fragmentary right side elevational view, with parts broken away and shown in section, showing constructional details of the carriage including the floating nut of Fig. 10, another floating nut for engaging a cross slide feedscrew, and a gib according to the present invention, taken substantially along the line 1 3- 13 of Fig. 5 and looking in the direction of the arrows; Fig. 1 3a is a fragmentary top plan detail view of the carriage;; Fig. 1 3b is an enlarged fragmentary front sectional elevational view of the feedscrew floating nut along line 1 3b1 3b of Fig. 1 3a and looking in the direction of the arrows; Fig. 14 is a fragmentary right side elevational view, with parts broken away and shown in section, showing a cross slide mounted to the carriage in accordance with the present invention; and Fig. 15 is a fragmentary'rear elevational view, with parts broken away and shown in section, showing constructional details of the cross slide and another gib associated with the cross slide according to the present invention, taken substantially along the line 1 5-1 5 of Fig. 14 and looking in the direction of the arrows.

Referring now specifically to the drawing, and initially to Fig. 1 thereof, there is shown an illustrative multiple-purpose machine tool embodying features of the present invention, generally designated by the reference numeral 20, and which includes an elongated machine bed 21 having a planar carriage surface 22 which extends longitudinally across a portion thereof, a tailstock 23 mounted at one end of the machine bed 21, a headstock 24 mounted at the other end of the machine bed, and a carriage 25 mounted for longitudinal movement along the carriage surface 22. To accurately guide the movement of the carriage 25, a pair of longitudinally extending dovetail ways 26a and 26b are formed at opposite sides of the machine bed 21 in parallel, spaced-apart relationship to each other.Dovetail ways 26a and 26b are constucted and arranged to confront and mate with corresponding dovetail edges 27a and 27b formed on the carriage 25, as seen more clearly in Figs. 13 and 14.

Referring again to Fig. 1, the present machine tool 20 preferably includes a cross slide 28 mounted for smooth sliding movement across the top of carriage 25 in a direction transverse to the longitudinal axis of the machine bed 21. Details of the cross slide 28 and its mounting are explained hereinafter in connection with Figs.13~15.

An important feature of the present invention is its ability to perform machining operations on a workpiece at a location convenient to the user, such as on a table or countertop, having surfaces which are not ordinarily truly flat or planar. As conventional tabletop machine tools have four mounting feet arranged in a rectangular or square configuration, all lying in a common plane, it is often necessary to provide shims or spacers between one or more of the mounting feet and the worktable surface to compensate for irregularities or lack of planarity in the work surface.If such shims were not used, fastening of all the mounting feet against the irregular work surface would cause distortion of the machine frame, and any critical surface, such as the present carriage surface 22 or the bed 21, can become irreparably distorted so as to render the machine virtually useless for precise machining.

The present machine tool 20 overcomes the mounting problems noted hereinbefore by providing only three mounting feet, each numbered 29 and shown most clearly in Fig. 5.

The feet 29 extend from the bed 21 and form a triangular arrangement, two of the feet 29 being located at respective ends of the machine bed 21 and extending longitudinally outwardly therefrom, and the third mounting foot 29 extending rearwardly or transversely from the bed 21.

As shown, the three mounting feet 29 define a plane in a triangle, the sides of which, from the rear foot to each of the side feet, are of the same or almost equal length; and the ratio of the normal distance between the rear foot and the longitudinal axis of the bed 21, to the overall distance between the two side feet, is about 0.27.

Of course, the exact distance between the mounting feet 29 are not critical, the important feature being that the geometry of their arrangement is that they define a plane which is sufficient to prevent rocking movement of the machine tool 20 during its operation and to maintain its carriage surface 22 substantially planar when the machine bed 21 is bolted or otherwise secured to a work surface.

Continuing now with reference to Fig. 1, it will be seen that the carriage 25 can be guided by dovetail ways 26a and 26b longitudinally over the carriage surface 22 in response to rotation of a carriage leadscrew 30. More particularly, a handwheel 31 is provided at one end of the machine bed 21 and is fixedly joined to a respective end of the carriage leadscrew 30. A floating nut 32 mounted on carriage 25 threadably engages the leadscrew 30.

Referring to Figs. 5 and 10, further details of the mounting of floating nut 32 on the carriage 25 are illustrated. Specifically, the nut 32 is in the form of a lug, and includes a cylindrical neck portion 33 for slidably engaging a corresponding bore 34 through a slide wall of the carriage 25, as shown. The neck portion 33 is preferably of circular cross-section and is of a diameter which is nominally about 1.5 mils (0.04 mm.) less than the diameter of the corresponding circular bore 34.It should be understood that the specific dimensions of the neck portions 33 and the bore 34 are for purpose of illustration only, the clearance provided for the neck portion 33 through the carriage bore 34 must be just sufficient to allow the nut 32 to tightly slide in a direction transverse to the carriage surface 22, and yet impart substantially immediate longitudinal movement to the carriage 25 in response to the rotation of the leadscrew 30 by the handwheel 31.

It will be understood that the manner of mounting of the nut 32 allows for minor irregularities in the axial alignment of the leadscrew 30 such as would otherwise cause the leadscrew 30 to bind within the nut 32, and thereby prevent further movement of the carriage 25. The carriage 25 can therefore be smoothly adjusted to a desired position along a path parallel to the longitudinal axis of the machine bed 21 with a corresponding smooth, comfortable feel being provided to the user by the handwheel 31 as it is being turned. The above construction regarding the floating nut 32 can also be impemented to obtain smooth positional adjustment of the cross slide 28 atop the carriage 25, if desired.

Another important feature of the present invention, also shown in Fig. 1, is the particular location of the carriage leadscrew 30 relative to the machine bed 21. Specifically, the leadscrew 30 is mounted beneath the carriage surface 22 for rotation about an axis parallel to the longitudinal axis of the bed 21. Referring to Fig. 5, a pair of axially aligned leadscrew bearings 35 and 37 are provided beneath the carriage surface 22, one bearing 35 being fixedly mounted through a side of the machine bed 21 adjacent the leadscrew handwheel 31, and the other bearing 37 being mounted through a partition wall 39 formed in the lower portion of the bed 21.

Accordingly, the leadscrew 30 is protectively shielded from scrap particles as a workpiece is machined by a cutting tool above the carriage surface 22. it will be understood that if the leadscrew 30 was left unprotected, as is the case in many of the prior machine tools, metal or other scrap particles are free to drop onto and lodge within the threads of the leadscrew. This in turn will cause binding of the leadscrew within the carriage nut and necessitate almost continuous, thorough cleaning of the machines's leadscrew both during and after each machining operation.

Shielding of the leadscrew 30 by the carriage surface 22 in accordance with the present invention substantially reduces the frequency with which the leadscrew 30 need be thoroughly cleaned.

The configuration of the present machine tool 20, as shown in Fig. 1, is such that the machine can perform horizontal, lathe-type machine operations such as boring, turning and facing.

Horizontal drilling and reaming can also be carried out with this machine configuration. Those skilled in the art will understand the fundamentals of machining a workpiece with the present machine 20 as set up in Fig. 1.

Basically, a chuck 38 is axially joined to a rotating spindle within the headstock 24 for rotation therewith, the particular workpiece (unshown) being sucurely gripped in a conventional manner within the jaws 40 of the chuck 38. A conventional cutting tool bit is mounted, in a well-known manner, in a post (unshown) which is secured to the cross slide 28 by being mounted within T-slots 11 5 in the top of the cross slide 28. A conventional motor drive unit 43, shown in greater detail in Figs. 3 and 12, operates to rotate the spindle 39 within the headstock 24 when a power switch 45 is actuated by the user.

Motor drive unit 43 is preferably protectively enclosed within a removable shell of plastic or like sturdy material. The motor therein, which should be of the synchronous type, operates to drive the headstock spindle 39 by a conventional V-belt and pulley arrangement. As shown in Fig. 12, an idler pulley set P is preferably interposed between a pulley joined to the motor, and a set of pulleys S axially joined to the headstock spindle. By the arrangement of Fig. 12, a user can obtain a desired rotational speed for the headstock spindle 39, depending upon the particular pulley selected on the idler pulley set P to be belted together with another pulley selected on the spindle pulley set S. Such a drive arrangement for the headstock spindle 39 is well-known to those skilled in the art and will therefore not be discussed in further detail.After turning the power switch 45 on, the machine tool 20 can then be used to perform the boring, turning or facing operations on the workpiece, depending upon the particular tool bit inserted by the user in the tool post of the present machine tool 20. In the event horizontal drilling is to be performed, a conventional drill bit (unshown) can be axially mounted within a ram 44 which is mounted for axial movement within the tailstock 23 in response to rotation of a handwheel 46. As the workpiece rotates within the chuck 38, the drill bit is advanced against the workpiece by axial movement of the ram 44 until the desired hole depth is obtained. Further details of the ram 44 are set out hereinafter in connection with Figs. 6 and 8.

The tailstock 23 can itself be moved longitudinally over the carriage surface 22 in order to bring the drill bit in the ram 44 to an initial starting position relative to the workpiece in the chuck 38. Such movement of the tailstock 23 is effected by sequentially loosening and tightening of a clamping bolt 48 running through the tailstock body as shown in Fig. 7. The bolt 48 acts to clamp dovetail edges 49a and 49b formed on tailstock 23 about dovetail ways 26a and 26b on the machine bed 21. A pair of clamping bolts 50 through the headstock body act to fixedly secure the headstock 24 and motor unit 43 on the machine bed 21 so that the headstock spindle 39 is maintained in axial alignment with the tailstock ram 44.One of the clamping bolts 50 is clearly shown in Fig. 4 as extending through the headstock body to clamp dovetail edges 51 a and 51 b formed on headstock 24 about the dovetail ways 26a and 26b.

As noted earlier, the multiple-purpose machine tool of the present invention is capable of performing vertical machining operations in addition to the horizontal machining operations described above. Such vertical operations include drilling, milling, sawing, boring and grinding.

Therefore, when combining these operations with the horizontal operations stated above, it will be appreciated that the present machine tool can perform most all machining operations which might be desired by both the amateur and professional alike.

As shown in Fig.2, for performing vertical machining operations, the tailstock 23 is removed from its operative position at one end of the machine bed 21, details of this removal step to be discussed hereinafter in connection with a discussion of Fig. 9. The headstock 24 is also removed from its horizontal operating position, at the other end of the machine bed 21, and is mounted atop a vertically oriented column 54.

The column 54 is vertically supported by way of a clamp 56 which extends rearwardlyfrom the machine bed 21, as shown more fully in Fig. 5.

Basically, clamp 56, which is preferably integrally formed with the machine bed 21, has vertical bore 58 therethrough for receiving the bottom of the column 54, and has a slot 60 extending from its rear end into the bore 58. This configuration allows the clamp 56 to be tightened about the inserted column 54 by way of a threaded bolt 62 extending through the clamp 56 perpendicularly to the slot 60. The rear mounting foot 29 preferably extends rearwardly from the mounting clamp 56.

In the preferred embodiment, motor drive unit 43 remains coupled to the headstock 24 for vertical machining operations, as shown in Fig. 2.

The headstock 24 and motor unit 43 are jointly supported for vertical reciprocating movement on the column 54 by a movable support assembly 64, as shown in greater detail in Figs. 11 and 12.

Generally, support assembly 64 includes a headstock mounting plate 68 having a pair of dovetail ways 70a and 70b formed on one surface thereof for engaging corresponding dovetail edges 51 a and 51b on the headstock 24, the other surface of plate 68 conforming to the shape of the column 54. A rear backing plate 72 (Fig. 2) is constructed and arranged to be formed with the mounting plate 68 for movement therewith, the confronting surface of the backing plate 72 also conforming to the shape of column 54. Sufficient clearance is provided between the plate 68 and 72, and the column 54, to allow the headstock 24 to be reciprocate vertically on the column 54 without skewing or binding thereon.

Vertical movement is imparted to the headstock 24 and motor unit 43 by movement of a handle 76 having a sector gear 78 joined at one end thereof. The handle 76 is mounted for pivotal movement between the mounting plate 68 and the backing plate 72 of the support assembly 64.

As shown in Fig. 1 gear 78 engages a corresponding rack 80 vertically joined to the side of the column 54. The sector gear 78 is pivoted to the support assembly 64 at 82 so that downward movement of the free end of the handle 76 will impart downward vertical movement to the mounted headstock and motor unit, and vice versa. Support assembly 64 can be moved to a desired position on column 54 and maintained thereat in a well-known manner by way of conventional friction or spring loading means mounted to the assembly 64 (unshown).

Referring again to Fig. 2, the present machine tool 20 is represented as arranged for a drilling operation upon a workpiece (unshown) to be secured within a vise 84 mounted atop the cross slide 28. Therefore, the workpiece can be accurately positioned beneath a drill bit 86 by appropriate movement of the carriage 25 and the cross slide 28, and by swiveling of the vise 84 which is preferably pivotally mounted atop cross slide 28 by way of the mounting hole 42 (Fig.1).

Referring now to Figs. 6 and 8, another important feature of the present invention will be described. As earlier mentioned, ram 44 is mounted for axial movement within tailstock 23 and is prevented from rotating therein. Ram 44 is normally moved by rotating handwheel 46 which is joined to a threaded rod 87. The rod 87 engages a corresponding threaded opening 89 extending axially through the ram 44.

Accordingly, rotation of ram 44 would cause it to advance along the rod 87 as the rod remains stationary. Ram 44 would then move toward or away from a workpiece, even though such movement is not intended by the user. Such rotation can be imparted to the ram, for example, when a drill bit secured therein is urged against a workpiece which is rotating in the headstock chuck 38. As the drill starts to cut into the workpiece, it will tend to be rotated along with the workpiece unless the ram 44 is properly restrained.

The above problem is solved in accordance with the present invention Wy way of a locking key plate 88 which is easily inserted and removed at the top of the tailstock 23. Locking key plate 88 is preferably planar and L-shaped in form as shown.

Ram 44 has a groove 90 cut longitudinally into its outer surface for engaging the leg 91 of the plate 88. The housing of taiistock 23 is constructed with one or more slots 92 running longitudinally across the top thereof, one of the slots 92 being in registration with the groove 90 in the ram 44.

An opening 94 is provided at the bottom of the latter slot to enable access to the ram slot 90 by the locking plate leg 91, as shown in Fig. 6. As best seen in Fig. 7, locking plate 88 is seated within the slot 92 and restrained from movement therein by the vertical walls of the slot 92, and a fastener such as a clamping bolt 96 which passes through the slot walls and an opening in the locking plate 88.

By the above construction, it will be appreciated that ram 44 is free to be moved axially within the tailstock 23 in response to rotation of the handwheel 46. Rotational movement of the ram 44, however, is restrained owing to the engagement of the seated locking plate 88 with the slot 90 in the ram 44.

Undesirable axial movement of ram 44 during operation of the machine tool 20 is thereby avoided.

Still another important feature of the present invention is illustrated in Fig. 9.

It is apparent that the carriage leadscrew handwheel 31 will be frequently used by an operator of the present machine tool 20 in order to move the carriage 25 along its surface on the machine bed 21. It is therefore desirable that rotation of the leadscrew 30 be easily and accurately controlled by the handwheel 31 so as to precisely adjust the position of the carriage 25.

Accordingly, the handwheel 31 should be of as large a diameter as possible to facilitate such control over the carriage movement. However, as the tailstock 23 is preferably removable from the machine bed 21 by sliding it off the end of the bed prior to vertical machining operations, it is possible for the handwheel 31 to interfere with the removal of tailstock 23 if the outer edge of the handwheel extends so far as to abut one of the dovetail edges 49a at the base of the tailstock 23.

The present invention provides a solution to the problem by having one or more grooves 100 cut across the outer edge of the handwheel 31 in a direction substantially longitudinally aligned with the carriage surface 22 on the bed 21. Each groove 100 is cut into the handwheel 31 to a depth sufficient to allow clearance of the dovetail edge 49a therethrough as the tailstock 23 is moved on or off of the bed 21.

Also, it is noteworthy that since the overall diameter of the handwheel 31 is sufficient to block movement of the tailstock 23 unless one of the grooves is properly aligned with the edge 49a, the tailstock 23 can be prevented from inadvertently falling or being thrust off from the end of the machine bed 21, where it is normally mounted, by rotating handwheel 31 to a blocking position.

Referring now to Figs. 13 and 14, additional refinements will be discussed. It is preferred that a gib 1 02 be interposed between one of the dovetail ways 26b on the machine bed 21, and the corresponding confronting dovetail edge 27b on the carriage 25, in order to facilitate smooth sliding movement of the carriage 25 over the carriage surface 22. The force with which the gib 102 bears against the dovetail way 26b is adjustable by way of one or more screws 108 which extend from the rear of the carriage 25 through respective threaded openings therein to abut the confronting side of the gib 102, the opening or openings overlying the gib 102.

As explained shortly hereinafter, a similar provision is made for the cross slide 28, which is shown mounted atop the carriage 25 in Fig. 14.

Cross slide 28 is preferably guided for movement atop the carriage 25 by a pair of parallel, spacedapart dovetail ways 109a and 109b formed atop the carriage surface and extending in a direction transverse to the longitudinal axis of the machine bed 21 (Fig. 15). Cross slide 28 has a pair of corresponding dovetail edges 111 a and 111 b for slidably engaging dovetail ways 109a and 1 09b, respectively.

Movement of the cross slide 28 in a direction transverse to the machine beds's longitudinal axis is governed by rotation of a feedscrew 112 (shown partially in Figs. 1 3a, 1 3b) which is joined at one end to the handwheel 36, and engages a second, shankless floating nut 114 which is slidably captured within opening 1 14a in carriage 25, as shown in Figs. 13, 1 3a, 1 3b and 14.

Floating nut 114 is preferably pill-shaped in form and includes a threaded opening running transversely through its body for engaging the feedscrew 112. The carriage opening 114a is preferably of a diameter which is nominally about 1.5 mils greater than the diameter of the body of the floating nut 114. It will be understood that as the nut 114 tightly slidingly engages the opening 11 4a for axial movement therein, it is supported within the opening 11 4a by the cross slide feedscrew 112.

The above construction and arrangement for the floating nut 114 overcomes problems experienced with rolled thread screws such as those commonly used for the carriage feedscrew 112. In particular, such screws are often not truly axially straight, so that rotation thereof at one end by a handwheel such as 36 can result in eccentric movement of the feedscrew 1 12 at the point where it engages the floating nut 114. In prior constructions, such movement of the feedscrew caused it to bind within a set of stationary threads usually provided in the carriage. As the present threaded nut 114 is free to slide within the opening 11 4a, it therefore complies with any eccentricity of the feedscrew 11 2 during its rotation by the handwheel 36, and binding of the feedscrew 112 is thereby avoided.

In addition to the mounting hole 42 atop the cross slide surface shown in Fig. 1, a pair of Tslots 115 are preferably included within and extending across the top of the cross slide 28 for use in mounting of various accessories thereon.

Another gib 11 6, as shown in Fig. 15, is interposed between one of the dovetail ways 109a provided on top surface of the carriage 25, and the corresponding confronting dovetail edge 1 1 lea on the cross slide 28. One or more threaded screws it 8, extending through respective threaded openings along the side of cross slide 28 which overlie the gib 11 6. operate to provide a desired tightness of movement for the cross slide 28 by urging gib 11 6 against the dovetail way 109a with a force adjustable by the user.

Yet another desirable feature of the present invention includes the provision of one or more Tslots 120 extending longitudinally along the top of the housing of the headstock 24, as indicated in Figs. 1 and 12. These slots can provide a means for mounting of accessory tools such as jig saws, band saws, and the like to the headstock housing for providing additional vertical machining operations to those usually available with prior machine tools.

As will be readily apparent to those skilled in the art, the invention may be used in other forms without departing from its spirit or essential characteristics. The present embodiment is, therefore, to be considered as illustrative and not restrictive, the scope of the invention being indicated by the claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein.

Claims (29)

Claims

1. A multiple-purpose machine tool comprising: an elongated machine bed having a planar carriage surface extending longitudinally across at least a portion thereof and having a pair of parallel spaced-apart dovetail ways at respective sides thereof; said bed including three mounting feet constructed and arranged for enabling said bed to be mounted on a work surface; said mounting feet being arranged in a triangular configuration to restrain said bed from rocking movement and to maintain said carriage surface substantially planar when said bed is operatively secured to said work surface; said bed further including a handwheel driven carriage leadscrew mounted for rotation about an axis parallel to the longitudinal axis of said bed beneath said carriage surface so as to be protectively shielded by said carriage surface; said leadscrew handwheel being fixed to said leadscrew at one end of said bed and having at least one groove extending across its outer edge in a direction substantially aligned longitudinally with said carriage surface; a headstock including a motor driven spindle; said machine tool including said headstock being constructed and arranged for said headstock to be selectable mountable at either a first location at the other end of said bed spaced from said one end wherein said spindle can be aligned parallel to said longitudinal axis or at a second location above said machine bed wherein said spindle can be aligned perpendicularly to said longitudinal axis; a tailstock including a ram constructed and arranged to be operatively aligned in axial confronting relationship with said spindle when said headstock is at said first location; said tailstock having dovetail edges for mounting said tailstock on said dovetail ways at said one end of said bed, and a slot extending longitudinally across the top thereof to receive a locking key plate for preventing rotation of said ram, one of said dovetail edges on said tailstock passing through said groove on said leadscrew handwheel when said handwheel is at a particular rotational position and said tailstock is move therepast; a carriage constructed and arranged for smooth sliding movement over said carriage surface, said carriage including a floating nut slidably mounted therein for engaging said leadscrew beneath said carriage surface so that said carriage can be smoothly adjusted along a path parallel to said longitudinal axis in response to rotation of said leadscrew; a cross slide constructed and arranged for smooth sliding movement transversely across the top of said carriage; said cross slide including a feedscrew for moving said cross slide along a path transverse to said longitudinal axis in response to rotation of said feedscrew.

2. A multiple-purpose machine tool according to Claim 1, further comprising a gib disposed between one of said dovetail ways on said machine bed and the corresponding confronting dovetail edge on said carriage for enabling said smooth sliding movement of said carriage over said carriage surface, said carriage having at least one threaded opening extending therethrough for receiving a correspondingly threaded screw, said opening overlying said gib so that said gib is urged against said dovetail way by a given amount in response to rotation of said screw.

3. A multiple-purpose machine tool according to Claim 1, further comprising a housing for enclosing said headstock having at least one slot extending along the top thereof for mounting another tool on said headstock housing when said headstock is mounted at said second location above said machine bed.

4. In a machine tool of the type including an elongated machine bed to be mounted on a work surface, said machine bed having a planar carriage surface extending longitudinally across a portion thereof for supporting a movable carriage, the improvement comprising three mounting feet on said machine bed for enabling said bed to be mounted on said work surface, said mounting feet being arranged in a triangular configuration to restrain said bed from rocking movement and to maintain said carriage surface substantially planar when said bed is operatively secured to said work surface.

5. An improved machine tool according to Claim 4, wherein first and second ones of said mounting feet extend longitudinally outwardly from respective ends of said machine bed, and a third one of said mounting feet extends transversely from said bed.

6. An improved machine tool according to Claim 5, wherein the respective distances between said third foot and each of said first and second feet are substantially equal.

7. An improved machine tool according to claim 6, wherein the ratio of the normal distance between said third foot and the longitudinal axis of said bed to the distance between said first and second mounting feet is about 0.27.

8. In a machine tool of the type including an elongated machine bed having a planar carriage surface extending longitudinally across a portion thereof, a carriage constructed and arranged for smooth sliding movement over said surface, and a leadscrew mounted for rotation about an axis parallel to the longitudinal axis of said bed, the improvement comprising a floating nut sidably mounted to said carriage for threadably engaging said leadscrew so that said carriage can be smoothly adjusted along a path parallel to said longitudinal axis in response to rotation of said leadscrew.

9. An improved machine tool according to Claim 8, wherein said floating nut extends through an opening provided in said carriage for tight sliding movement in a direction transverse to said carriage surface.

10. An improved machine tool according to Claim 9, wherein said floating nut is in the form of a lug having a neck portion formed to engage said opening.

11. An improved machine tool according to Claim 10, wherein said neck portion is of circular cross-section and said opening is defined by a cylindrical bore having a nominal diameter about

1.5 mils (0.04 mm.) greater than that of said neck portion.

12. In apparatus of the type including two members constructed and arranged to be adjustably movable relative to each other over a predetermined path, and an elongated threaded rod mounted to one of said members for rotation about the longitudinal axis of said rod and for engaging corresponding threads formed in an opening in the other of said members to impart said relative movement in response to rotation of said rod, the improvement comprising a floating nut at least partially contained within a first opening in said other member and having said corresponding threads formed in a second opening extending through said floating nut, said first opening conforming to the dimensions of the portion of said floating nut contained therein so that said floating nut is substantially free to move with respect to said other member in a direction transverse to said longitudinal axis and is substantially restrained from movement with respect to said other member in a direction parallel to said longitudinal axis, wherein said floating nut complies with eccentric movement of said rod to enable said relative movement to be smoothly adjustable over said predetermined path when said rod is rotated within said second opening.

13. In a machine tool of the type including an elongated machine bed having a planar carriage surface extending longitudinally across a portion thereof, a carriage constructed and arranged for smooth sliding movement over said surface, and a cross slide constructed and arranged for smooth sliding movement transversely across the top of said carriage, said cross slide including a feedscrew for moving said cross slide along a path transverse to the longitudinal axis of said machine bed, the improvement comprising a floating nut slidably mounted to said carriage for threadably engaging said feedscrew so that said cross slide can be smoothly adjusted along said path in response to rotation of said feedscrew.

14. An improved machine tool according to Claim 13, wherein said floating nut extends through an opening provided in said carriage for tight sliding movement therein.

15. An improved machine tool according to Claim 14, wherein said floating nut is in the form of a pill which is captured for axial movement within said opening and is supported therein by said feedscrew.

16. An improved machine tool according to Claim 15, wherein said opening has a nominal diameter about 1.5 mils (0.04 mm.) greater than that of said floating nut.

17. In a machine tool of the type including an elongated machine bed, a leadscrew mounted for rotation about an axis parallel to the longitudinal axis of said bed, one end of said leadscrew extending from one end of said bed, and a tailstock removably mountable at said one end of said bed, said tailstock having edges for mounting said tailstock on corresponding ways at said one end of said bed, the improvement comprising a handwheel axially joined to said one end of said leadscrew, said handwheel having at least one groove extending across its outer edge, said groove being of sufficient depth to allow one of said edges on said tailstock to pass therethrough when said handwheel is at a particular rotational position and said tailstock is moved therepast.

18. An improved machine tool according to Claim 17, wherein said handwheel is generally circular and of an overall diameter sufficient to block movement of said tailstock past said handwheel when said handwheel is at a position other than said particular rotational position.

19. In a machine tool of the type including an elongated machine bed having a carriage surface extending longitudinally across a portion thereof, the improvement comprising a leadscrew mounted for rotation about an axis parallel to the longitudinal axis of said bed beneath said carriage surface so that said leadscrew is protectively shielded by said carriage surface.

20. An improved machine tool according to Claim 19, wherein said carriage surface is planar and overlies said leadscrew so that particles from a workpiece above said carriage surface are prevented from falling within threads of said leadscrew by said carriage surface.

21. In a machine tool of the type including an elongated machine bed, a headstock for supporting a spindle along an axis parallel to the longitudinal axis of said bed, and a tailstock for operatively supporting a ram in axial confronting relationship with said spindle, the improvement comprising a removable locking key plate for preventing rotation of said ram, said tailstock having an opening extending longitudinally across the top thereof for operative insertion of said key plate.

22. An improved machine tool according to Claim 21, wherein said locking key plate is planar and L-shaped in form having a leg extending therefrom, and said ram has a groove formed longitudinally in its outer surface in registration with said tailstock opening for receiving said leg so that said ram is free to move axially and is restrained from rotative movement about its axis when said key plate leg is inserted through said opening to engage said groove.

23. An improved machine tool according to Claim 22, further including means for seating said locking plate about said opening.

24. An improved machine tool according to Claim 23, wherein said seating means comprises a pair of walls each extending longitudinally and upwardly from said tailstock on respective sides of said opening to retain said key plate therebetween, and a fastener extending transversely through said walls and said key plate, said walls and said fastener being constructed and arranged to maintain said locking plate stationary.

25. In a machine tool of the type including an elongated machine bed having a planar carriage surface extending longitudinally across at least a portion thereof and having a pair of parallel spaced-apart dovetail ways at respective sides thereof, a carriage having a pair of parallel spaced-apart dovetail edges formed thereon for confronting and mating with said dovetail ways, respectively, so that said carriage is guided for movement over said carriage surface by said dovetail ways, the improvement comprising a gib disposed between one of said dovetail ways and the corresponding confronting dovetail edge on said carriage for enabling smooth sliding movement of said carriage over said carriage surface, said carriage having at least one threaded opening extending therethrough for receiving a correspondingly threaded screw, said opening overlying said gib so that said gib is urged against said dovetail way by a given amount in response to rotation of said screw.

26. An improved machine tool according to Claim 25, wherein said carriage has a pair of spaced-apart dovetail ways formed on top thereof transversely to the longitudinal axis of said machine bed, and further including a movable cross slide having a pair of dovetail edges formed thereon for slidingly engaging said dovetail ways on said carriage, another gib disposed between one of said carriage dovetail ways and the corresponding confronting cross slide dovetail edge for enabling smooth sliding movement of said cross slide over the top of said carriage, said cross slide having at least one threaded opening extending therethrough for receiving another correspondingly threaded screw, said cross slide opening overlying said other gib so that said other gib is urged against said carriage dovetail way be a given amount in response to rotation of said other screw.

27. In a machine tool of the type including an elongated machine bed, a tailstock operatively mounted at one end of said bed and a headstock selectably mountable at either the other end of said bed to enable horizontal machining operations or above said bed to enable vertical machining operations, the improvement comprising a housing for enclosing said headstock having at least one slot extending along the top thereof for mounting another tool on said headstock housing when said headstock is mounted above said machine bed.

28. An improved machine tool according to Claim 27, wherein said at least one slot extends longitudinally along the top of said headstock housing.

29. An improved machine tool according to Claim 27, wherein said at least one slot is a Tslot.