US2900766A - Machine tool - Google Patents

Description

Aug. 25, 1959 Filed May 29, 1958 P. J. ROBISCHUNG 2,900,766

MACHINE TOOL 2 Sheets-Sheet 1 INVENTOR.

PHILIP .J. ROBISCHUNG BY [0% BWMQ ATTORNEYS Aug; 25, 1959 P. J. ROBISCHUNG 2,900,766

. MACHINE TOOL Filed May 29, 1958 2 Sheets-Sheet 2 INVENTOR.

PHlUP 1 J. RDBLSCHUHG ATTORNEYS 2,900,766 Patented Aug. 25, 1959 MACHINE TOOL Philip J. Robischung, Kalamazoo, Mich., assignor to Hammond Machinery Builders, Inc., Kalamazoo, Mich, a corporation of Michigan Application May 29, 1958, Serial No. 738,869

4 Claims. (Cl. 51-448) This invention relates to an apparatus for effecting a controlled mechanical force at a desired point and it relates particularly to interchangeable means for applying either a spring or a fluid pressure created force onto a tensioning pulley of a belt-type abrading machine. An example of the type of machine to which the present invention is especially applicable is found in Us. Patent No. 2,612,007 assigned to the assignee of the present invention.

While the present invention was developed particularly out of a desire for belt-tensioning means in a belt-type abrading machine, of the type above indicated, by which 2 means the tensioning force could be either spring or fluid pressure, as desired, it will be recognized that the struc ture of the invention can be applied to a wide variety of other uses. Accordingly, while the invention is hereinafter illustrated and described in terms of a belt-type abrading machine, it will be recognized that such specific reference is for illustrative purposes only and is not limiting. I

In the use of belt-type abrasive machines, it is necessary to have some device, often a pulley, bearing against the belt for holding a controllable tension thereon. Some installations prefer to apply to such device a mechanically, as spring, created force for effecting such belt tension, and other installations employ a pressure fluid, such as compressed air, to create such belt-tension.

The choice of these alternate sources of tension is primariiy a matter of economics. It is generally recognized that air tensioning provides superior operation in that a greater tensioning force can be conveniently obtained and the force can be applied more smoothly, but the spring tension often is acceptable and involves much less cost. Thus, for otherwise identical machines, some customers will specify air tensioning of the abrasive belt whereas other customers will specify spring tensioning. In order to minimize inventory requirements in the manufacturing plant, it becomes desirable to design the machines so that they are as nearly identical as possible, whether air tensioned or spring tensioned, whereby the adaptation of a given machine to one or the other type of tensioning can be made very simply by only a few steps which can be carried out at the extreme end of the manufacturing operation. In this manner the machines can be built practically to the point of completion and held in inventory. When a customers order is received, an appropriate unit can then be quickly completed by only a few steps in Y which such unit is adapted for air tensioning or spring tensioning as specified by the customer.

Thus, it has long been desirable to provide a construction by which this election can be made in the final stages of the manufacturing of a given machine and appropriate apparatus installed into such machine in accordance with a given customers order.

Further, it often happens that the machine is sold with one typeof tensioning apparatus and subsequently, during its useful life, the conditions, as above discussed, under which it operates change and it is preferred to'have a different type of belt-tensioning means utilized, in which case it is desirable that the belt-tensioning means be readily capable of modification from one type of belttensioning device to the other type thereof.

Accordingly, a principal object of the invention has been to provide belt-tensioning means for a belt-type abrasive machine which can be readily changed from spring-type tensioning apparatus to pressure-fluid type apparatus, or vice versa, at a point late in the manufacturing operation of a given machine or even after the machine is completed and installed at the users premises.

A further object of the invention has been to provide apparatus, as aforesaid, in which the conversion from one type of belt-tensioning apparatus to another type of such apparatus can be carried out quickly, easily, by ordinary workmen and by the use of ordinary tools.

A further object of the invention has been to provide apparatus, as aforesaid, in which structure adaptable to either type of tensioning means is built into the basic structure of the machine and is merely provided with different and easily installed fittings to render it of one operating type or the other.

A further object of the invention has been to provide apparatus, as aforesaid, in which a portion of the belttensioning apparatus also functions as a structural strengthgiving part of the machine frame.

A further object of the invention is to provide apparatus, as aforesaid, which in either of its possible arrangements provides a structure of substantially greater strength than is normally obtainable from presently known designs and wherein said additional strength can be obtained without appreciable additional cost.

A further object of the invention has been to provide apparatus, as aforesaid, in which the conversion from one type of tensioning means to the other type thereof can be carried out without removing parts other than the upper pulley assembly and belt from their respective op erative positions.

. A further object of the invention has been to provide apparatus, as aforesaid, in which the parts will operate as effectively for either spring tensioning or pressure-fluid tensioning as is at present customarily obtained by apparatus directed solely to one of said two belt-tensioning types of operation.

Other objects and purposes of the invention will be apparent to persons acquainted with devices of this general type upon reading thefollowing specifications and inspection of the accompanying drawings.

In the drawings:

Figure l is a broken rear view of a belt-type abrading machine with tensioning apparatus embodying the invention installed therein.

Figure 2 is a sectional view taken along the line IIII of Figure l and showing a central sectional view of the abrading machine in Figure 1 and the spring-type belttensioning apparatus installed therein.

Figure 3 is a section taken along the line III-III of Figure 1. V v 1 Figure 4 is a fragmentary showing corresponding to the Figure 1 and illustrating the installation of pressure-fluid type tensioning means according to the invention.

' General description In general, the invention comprises providing a generally cylindrical housing rigidly within a frame structure supporting the pulleys over which the abrading belt travels. Said frame structure may advantageously be built with the cylinder rigidly cast therein. A piston extends into said cylinderand provides a mounting base for one of the belt-supporting pulleys. Adjustable resilient means are'provided for hearing against said piston within said cylinder for mechanical tensioning thereof. Alternatively, the piston above-mentioned is replaceable by a piston 3 of slightly different design, the cylinder closed and pressure-fluid source means provided for applying the required pressure to said last-named piston and thence to the belt-carryingpulley.

Detailed description For the purpose of convenience in description, certain terminology will be used which will be understood to be for convenience only and not limiting. For example, the terms upward and downward and derivatives thereof will refer'to directions with respect to the machine in its normal position of operation and/or as shown in the drawings. The terms forward and rearward and derivatives thereof will refer respectively to positions toward and away from the operators side of the machine. The terms leftward and rightward and derivatives thereof will refer to directions as appearing in individual drawings which may be under discussion when said terms are used and, particularly, reference to the rearward side of the machine refers to the side which appears as leftward in Figure 2. Lastly, the terms inward and outward and derivatives thereof will refer respectively to directions toward and away from the geometric center of the apparatus.

Referring now to Figure 1, a generally rectangular box-like, frame structure 1 only partially shown, but of known type, is provided for supporting pulleys 2- and 3 in any suitable manner for carrying an abrasive belt 5. The frame 1 is supported in any convenient manner well known to the art and not shown here. A yoke 4 has an opening 4a therein which receives a stem at the upper end of the piston 6 which may then be rigidly fastened to said yoke by a suitable pin 60. A guide 7 is received between a pair of blocks, of which one appears at 8, for adjusting the yoke 4 about the axis of the piston 6, whereby the axis of the pulley 3 is placed as close as possible into parallelity with the axis of the pulley 2 for reasons which are well known in the industry.

An upper plate 11 extends across the upper end of the frame structure 1 and in this particular embodiment of the invention, said upper plate 11 is cast integrally with said frame structure 1. An opening 12 is provided through said upper plate 11 coaxial with the opening 4a and normally substantially concentric with an axis passing through the geometric center of the frame structure l. A cylinder 13 extends downwar ly from the plate 11 and supports a hollow box 14 at the lower end thereof. Said box is fixed rigidly to the walls 16 and 16a of. the frame structure 1. Said cylinder 13 and the box 14 are all preferably provided by casting same integral with the upper plate 11 and the walls 16 and 16a of the frame 1 with which they are associated. The rearward side of the box 14 is open but may be closed by a bolted-on plate as will appear more fully hereinafter. A platen 21 is provided at the front of the frame.

The lower end of the box 14 has a boss 17 provided thereon through which extends an opening 18 which may, if desired, be lined with suitable bearing material and through which rotatably extends the shaft 19. A collar 21 holds said shaft 19 against upward movement and a bevel gear 22 is mounted for rotation with said shaft and holds it against downward movement. A further shaft 23 extends through an opening 24 in the wall 16, carries a bevel gear 26 for rotation therewith and also carries the crank structure 27 for manual rotation thereof. The bevel gears 22 and 26 are meshed with each other.

The piston 6 is counterbored to provide a central chamber 28 therein. A spring 29 is received within said central chamber 28 and is held therein by the nut31. Said nut is threadedly engaged with the shaft 19 so that rotation of said shaft effects an axial movement of said nut and thereby adjusts thetension on the spring 29. Diametric and elongated slots 32 and 33 are provided through the sides of the piston 6 for reception of the 4 1 heads of screws 34 and 36, which screws are received fixedly into the nut 31. The heads of said screws being in the slots 32 and 33 prevent relative rotation of said nut with respect to said piston.

A further slot 37 (Figure 2) is provided in the outer surface of the piston 6 and a threaded opening 38 is provided in the cylinder 13 in radial register therewith. A screw 39 is threaded into said opening 38 and extends into the slot 37 for limiting the upward and down ward travel of the piston 6 with respect to the cylinder If desired, a groove 40 may be provided around the external periphery of the piston 6 for lubrication purposes, lubricant being supplied thereto through a suitable opening provided with a fitting 45 (Figure 1).

Thus, manual rotation of the crank 27 acts through the bevel gears 26 and 22 to rotate the shaft 19 and thereby move the nut 31 axially upwardly or downwardly. This tightens or relieves the tension on the spring 29 and thereby adjusts the force by which said spring urges the piston 6 upwardly and this in turn applies an adjustable mechanically resilient force onto the pulley 3 for tensioning the belt 5.

Turning now to the pressure fluid responsive mechanism, attention is directed to Figure 4 wherein the parts corresponding to the parts already disclosed and described in connection with Figures 1 through 3 are provided with the same numbers as appearing in Figures l to 3. Here, however, the piston 6, the nut 31, the shaft 19, the bevel gears, the hand wheel and other incidental screws, nuts, washers and similar parts associated with each thereof are all removed and replaced by the pressure fluid responsive devices now to be described. These include a piston 41 taking the place of the piston 6 and a pressure sealing diaphragm 42, as a common piston leather. A screw 43 and washer 44 hold said pressure sealing device firmly against the end of the piston 41. The cylinder is closed by a partition 46 having a peripheral groove for receiving the lower end of the walls defining the cylinder 13. An opening 48 extends through the partition for the introduction and removal of pressure fluid into and from the space between the partition 46 and the sealing diaphragm 42. The partition 46 is held in place merely by a bolt 49 extending partially into the opening 18 and tightened into position by a nut 51. A gasket 52 may be provided if desired between the lower end of the cylinder 13 and the adjacent wall of the partition 46. A suitable conduit 53 is connected into the opening 48 for the introduction of pressure fluid through said opening and removal of pressure fluid therefrom.

It will be recognized that the conversion of the apparatus from one form of tensioning mechanism to the other form can be done quickly without the use of special tools, by ordinary maintenance personnel and without seriously disturbing the other parts of the abrading machine. For example, in removing the spring tensioning apparatus, it is necessary only to remove the piston 6 and the parts associated therewith, together with the shaft 19, the bevel gears and the handle 27 all of which are readily accessible and can be easily removed. While it is necessary to remove the belt from the pulleys in order to render the yoke 4 and the piston 6 capable of moving upwardly out of the cylinder 13, this can be readily accomplished inasmuch as the belt and the pulleys are also easily accessible. reached through the back of the machine, loosened from their respectiveshafts and then removed through the back of the machine after said shafts are withdrawn. When these parts are removed, the piston 41 is then placed into the opening 4a of the yoke 4 and slipped into the cylinder 13. The cylinder 13 and the box 14 associated therewith are not disturbed in any respect nor in any other part of the frame of the machine nor is the lower pulley. The partition 46 can be inserted through the back of the machine and through the opening in the back of the box 14. The screw 49 and the nut 51 can also be inserted The bevel gears can be,

through the back of the box 14 and the nut 51 then suitably tightened. The plate 15 may in this case be omitted or if used it may be provided with a suitable opening for the passage of the conduit 53. Otherwise, said conduit, as shown in Figure 4, may be passed through the shaft opening 24. I

While the specific embodiment of the invention has been utilized herein for illustrative purposes, it will be recognized that the invention may be embodied in a wide variety of specific devices and, accordingly, the hereinafter appended claims will be interpreted to include such other devices excepting as said claims, by their own terms, may expressly require otherwise.

What isclaimed is:

1. In a belt-tensioning apparatus for a belt-type abrading machine, the combination comprising: a movable belttensioning pulley; a hollow frame structure, said frame structure including wall means defining a cylinder having open ends and closed side walls and whose axis is parallel to the direction of movement of said belttensioning pulley; a piston movable in said cylinder and extending through one end thereof and terminating within said cylinder and means connecting said piston to said belt tensioning pulley whereby belt-tensioning force may be applied by moving said piston within said cylinder; said frame also including wall means defining a hollow box located at the other end of aid cylinder remote from said belt-tensioning device and communicating therewith; said piston having an internal chamber therein and a nut positioned in said chamber at the end thereof adjacent said hollow box, said nut being axially, but not rotatably, movable within said chamber; a coil spring positioned within said chamber and hearing at one end thereof against said nut and hearing at the other end thereof against the opposite end of said chamber; said hollow box having an opening in the end wall thereof opposite said other end of said cylinder and substantially coaxial therewith; a threaded rod extending through said opening and threadedly engaging said nut whereby upon rotation of said rod said nut will be moved axially within said chamber to adjust the tension exerted by said spring on said piston; said box having an opening through the side wall thereof; a manually rotatable shaft extending through said last-named opening and gearing connecting said shaft to said rod whereby said rod will be rotated upon rotation of said shaft.

2. In a belt-tensioning apparatus for a belt-type abrading machine, the combination comprising: a movable belt tensioning pulley; a hollow frame structure, said frame structure including wall means defining a cylinder having open ends and closed side walls and whose axis is parallel to the direction of movement of said belt-tensioning pulley; a piston movable in said cylinder and extending through one end thereof and terminating with said cylinder and means connecting said piston to said belt tensioning pulley whereby belt-tensioning force may be applied by moving said piston within said cylinder; said frame also including wall means defining a hollow box located at the other end of said cylinder remote from said belt-tensioning device and communicating therewith; said hollow box having an opening in the end wall thereof opposite said other end of said cylinder; a block positioned within said box and sealingly contacting said other end of said cylinder and closing oif the opening therein at said one end; a bolt in said box and bearing against block, said bolt extending into said opening and a nut threadedly engaging said bolt and bearing against said opposite end wall of said box whereby said bolt may be adjusted to hold said block in position; said box having an opening through the side wall thereof; a fluid pressure conduit extending said last-named opening; said block having an opening therethrough and means connecting said conduit to said opening whereby fluid pressure may be applied to move the piston with said cylinder.

3. In a belt tensioning apparatus for a belt type abrad ing machine, the combination comprising: a movable belt tensioning pulley; a hollow frame structure, said frame structure including wall means defining a cylinder having open ends and closed side walls and whose axis is parallel to the direction of movement of-said belt tensioning pulley; a piston movable in said cylinder and extending through one end thereof and means connecting said piston to said belt tensioning pulley whereby belt tensioning force may be applied by moving said piston within said cylinder; a block sealingly contacting the other end of said cylinder and closing off the opening therein at said other end; means supported on said frame and bearing against said block for holding said block in position; a fluid pressure conduit extending through said frame; said block having an opening therethrough and means connecting said conduit to said opening whereby fluid pressure may be applied to move the piston within the cylinder.

4. In belt tensioning apparatus for a belt-type abrading machine, the combination comprising; a movable belttensioning pulley and a piston connected to said pulley, a frame for receiving said piston, said frame including wall means defining a cylinder having open ends. and closed side Walls and whose axis is parallel to the direction of movement of said belt-tensioning pulley, said piston being slidably received in said cylinder through one end thereof and terminating within said cylinder, said frame also including wall means defining a hollow box located at the other end of said cylinder remote from said belttensioning pulley and communicating therewith, said box having an opening in the end wall thereof opposite said other end of said cylinder and substantially coaxial therewith, said box having an opening through the side wall thereof, said openings in the walls of said box being adapted to receive elements therethrough for moving said piston within said cylinder, said piston being round and having an axially extending slot in the side wall there of in the portion thereof received within said cylinder, and a pin extending through a side wall of said cylinder and extending into said slot for permitting axial movement of said piston within said cylinder but preventing rotation of said piston with respect to said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 2,489,811 Perkins NOV. 29, 1949 FOREIGN PATENTS 16,756 Great Britain Jan. 21, 1914-

Images