Apparatus For Securing And Aligning Two Elements With Respect To Each Other In Orthogonal Planes

Abstract

An apparatus secures and aligns distinct elements in two orthogonal planes. Each of said elements contains a key slot designed to accept a locating means when the desired surfaces of the elements are engaged with each other. The locating means is a key member that fits loosely in the slots wherein one wall of the key member forms a plane that obliquely passes through the plane of the desired surfaces and another wall of the key member engages the edge of the slot of one of the elements in a manner causing lateral movement of the elements with respect to each other when the key member is adjusted to move in a direction perpendicular to said lateral movement.

Description

BACKGROUND OF THE INVENTION

In the machine tool industry, rectangular, hardsurfaced ways are secured to machinery bases as bearing surfaces for slideable elements. The accuracy of the machine tool is to a large extent dependent upon the accuracy with which the ways are located and secured to the base structure. In the past, key slots and keys have been utilized to locate the way on the machine base. The accuracy of the way alignment was therefore dependent upon the precision of the key slot in the way and its matching slot in the base. This required that the key slot be held parallel to the outside walls of the way and also parallel and straight in the machine base.

Mounting a way in this manner has proved costly and time consuming. As machine capacity increases over the years, longer and larger ways become an ever increasing cost factor in the manufacturing process.

SUMMARY OF THE INVENTION N

The present invention provides a means for aligning and securing ways to a machine base without requiring precision keys and key seats. This is achieved by utilizing a locating means that fits loosely in the key slots when the way is placed upon the bed. One wall of the locating means forms an oblique angle with the sidewall of one of the slots providing the function of a wedge. Another wall of the locating means is engaged with the opposite edge of the other slot. Thus, as the locating means is caused to move into or out of the first slot, the way moves in a manner perpendicular to the direction of movement of the locating means. This allows the way to be aligned in two distinct planes necessary to insure accuracy of the machine tool.

This also results in a more rigid final assembly.

DRAWINGS

FIG. 1 is a section view looking at an end portion of the prior art device.

FIG. 2 is a section view similar to FIG. 1 illustrating the preferred embodiment of the present invention.

FIG. 3 is a section view taken along lines 3--3 of FIG. 2, showing a base and way structure utilizing a plurality of locating elements of the present invention.

DESCRIPTION

Referring first to FIG. 2, a first element, such as a way 10 for a machine tool, is mounted on a second element, such as the base 12 of the machine tool, and secured in place by a mounting means 14, for example, a bolt threaded and secured into a tapped hole. It can be seen that the basic configuration shown in FIG. 2 is the same as utilized by the prior art in FIG. 1. It is necessary that the way 10 and the base 12 be aligned with each other in two perpendicular planes. In the present case, the surface 16 of way 10 and the surface 20 of base 12 represent the first plane of alignment. The surface 16 and 20 are called the bottom and top surfaces, respectively. This is for convenience and does not necessarily indicate their spatial relationship. The second plane of alignment is represented by surface 18 of the way 10 and surface 22 of the base structure 12. In the prior art, it can be seen that the second plane of alignment was represented and controlled by the wall 60 of key 24 and the wall 62 of the way 10.

The prior art utilized a simple key 24 held in place by the bolt 26 to locate the way surfaces that bear upon base structure 12. As can be seen, in FIG. 1, the accuracy of the location of the way 10 with respect to the base structure 12 was entirely dependent upon the accuracy of key slots 28 and 30, and the precision of key 24. The surface 62 and surface 64 of way slot 28 had to be held parallel with respect to each other and with the outside walls 66 and 68 of the way 10. Further, the slot 30 in base 12 had to be straight and held in parallel with the intended direction of the walls 66 and 68 of way 10.

The preferred embodiment of the present invention illustrated in FIG. 2 provides means for aligning the bearing surfaces 16 and 18 along the surfaces 20 and 22, respectively, without depending upon the accuracy of key slots 32 and 34. The key is semi-wedge shaped, rather than a rectangular solid as key 24 of the prior art. The key 36 of the preferred embodiment has a trapezoidal cross-section. However, any type of configuration producing the result substantially herein described could be utilized. Key 36 is held loosely in slot 34 by mounting bolt 38 which passes through clearance hole 40 of the base 12. The threads 42 of bolt 38 are matched with tapped hole 44 of key 36. Key 36 is held loosely in place by bolt 38.

The way 10 is then placed on base structure 12 as illustrated. The threads 48 of bolt 14, which passes through clearance hole 46 in base structure 12, are matched with tapped hole 50 of the way 10. As bolt 14 is tightened, bearing surface 16 of way 10 is secured against bearing surface 20 of base 12. When bolt 38 is turned, key 36 either moves into or out of slot 34. At least one point of side 52 in slot 34 is in contact with the inclined edge 54 of key 36. Generally, it is best if the angle of edge 54 and side 52 are approximately equal, providing a greater bearing surface between the key 36 and the key slot 34. As key 36 is moved into or out of slot 34 the key is also forced to move laterally to the right or the left. Surface 22 of the base 12 is straight and in a direction parallel to the intended direction of the wall 66 and 68 of the way 10. Thus, it can be seen the surface 22 replaces the function of the accuracte key slot 30 in the prior art. Surface 18 of way 10 is held parallel to wall 66 and 68. Thus, when surface 18 is aligned and engaged with wall 22, the walls 62 and 68 of way 10 are parallel with wall 22.

When the way 10 is placed on the base structure 12, bearing surface 18 is not in contact with the bearing surface 22. The bolt 14 is next tightened enough to hold the top surface 16 against the bottom surface 20, but loose enough to permit the surface 16 to move laterally with respect to surface 20. Key 36 is moved into slot 34 forcing the key 36 to move laterally to the right, bringing key edge 56 in contact with side 58 of slot 32. As the key 36 is moved further into the slot 34, the way 10 is forced to the right, bringing bearing surface 18 into contact with bearing surface 22. The bolts 14 and 38 can then be tightened to preselected torque, securing the way 10 on the base structure 12.

One advantage to this apparatus is the time saving over the prior art device. By utilizing keys and slots which do not require precise dimensions, the machining time is reduced. A further advantage is the rigidity of the final assembly. Both the way 10 and the securing elements are held in tension. In the prior art device only the securing elements were held in tension and the way had a hysteresis factor which has been virtually eliminated in the present invention. This hysteresis is caused by the amount of slack between the key 24 and the slots 28 and 30 in the prior art device. It can be seen if the way 10 is held in tension, being forced against one edge of the key, this slack space will be eliminated.

FIG. 3 illustrates use of the invention when a long way, requiring a plurality of locating members, is secured to a machine base. The cutting plane indicated by lines 3--3 of FIG. 2 corresponds with bearing surface 20 of base structure 12. When the way 10 is placed upon base 12, top and bottom surface 16 and 20 will be bearing against each other.

In the prior art device, the key slot 30 and the key slot 28 have to be parallel with respect to each other as well as with respect to walls 66 and 68. Also, the key 24 had to fit securely in slot 30 and slot 28 in order to insure the accuracy of the placement of the way 10. The total misalignment would be a sum of the error of both key slots 28 and 30, and would be magnified by the imprecision of the key 24. Therefore, to insure accuracy in the alignment of way 10 with respect to base 12, each of the slots 28 and 30 has to be machined to an error of not more than one-half of the total error permitted for misalignment. Furthermore, the key 24 had to fit precisely into each of these slots.

In the present invention, this problem has been eliminated (see FIG. 3). As herein described, the keys 36 are loosely held in the slot 34 when way 10 is positioned upon base 12. Bolts 14 are tightened enough to secure way 10 to base 12, but remain loose enough to permit the way 10 to slide on bearing surface 20 of base 12. To bring bearing surfaces 18 and 22 into an alignment and engagement, it is only necessary to tighten bolts 38 drawing keys 36 into the slot 34. Since each key 36 is semi-wedge shaped, having at least one inclined edge 54, the way 10 will be moved to the right as bolts 38 are tightened. This will bring bearing surface 18 into contact with bearing surface 22.

If the slot 32 or the slot 34 is not in proper alignment, or the keys 36 are of different sizes, each key need only be drawn into slot 34 a different amount at each location to compensate. Each key 36 is drawn into slot 34 enough to cause engagement between bearing surfaces 18 and 22 along the entire length of the way. After this has been achieved, all bolts 14 and 38 can be tightened to a preselected torque, properly securing way 10 to base structure 12.

It should be understood that the foregoing is only illustrative and is not intended to limit the spirit of invention or the scope of the appended claims.

Claims

What is claimed is:

1. An apparatus for rigidly and permanent securing and aligning distinct elements in two orthogonal planes wherein there is located in the bottom surface of one of said elements a first key slot and in the top surface of the other of said elements a second key slot designed to accept a locating means when the bottom and top surfaces of the respective elements are engaged, said locating means comprising:

a. a key member fitting loosely in said first and second slots:

i. one wall of said key member defining a plane that passes obliquely through the plane of the top surface of said other element;

ii. another wall of said key member opposite said one wall adapted to engage an edge of said first slot; and

b. means for adjusting said locating means in a manner causing two orthogonal directions of movement for generating a force against the edge of said second slot and causing movement to said one element with respect to said other element.

2. An apparatus for permanently aligning and rigidly securing a machine tool way to support structure wherein there is a first key slot in the bottom surface of said way, and a corresponding key slot in the top surface of said support structure, said slots being suitable for accepting a locating means when said way is engaged with said support structure, said locating means comprising:

a. a key member designed to fit loosely in said slots:

i. one wall of said key member defining a plane that passes obliquely through a first plane, said first plane corresponding to the top surface of said support structure;

ii. another wall of said key member opposite said one wall adapted to engage an edge of said first slot; and

b. means for adjusting said locating means in a manner causing movement of the way with respect to the surface structure in said first plane when said locating means is adjusted to move in a direction perpendicular to said first plane.

3. The apparatus of claim 2 wherein said locating means further comprises a rigid member wherein:

a. a first section through said member, parallel to the top surface of said support structure, forms substantially a rectangle; and

b. a second section of said member, perpendicular to said first section, forms a trapezoid having one edge thereof forming an oblique angle with the top surface of said support structure and being substantially parallel to one wall of said second slot.

4. The apparatus of claim 2 wherein said means for adjusting the locating means further comprises:

a. a bolt with a head and threaded body;

b. a passage through said support structure which is larger than said body but smaller than said head; and

c. a tapped hole in the locating means suited to accept the threaded body of said bolt for permitting adjustment of the locating means by rotation of said bolt.