US 3432934 A
Description (OCR text may contain errors)
March 18, 1969 scH 3,432,934
SINE PLATE ASSEMBLY Filed Aug. 30. 1966 INVENTOR. HERMANN SC HMI DT ATTORN EYS 3,432,934 SINE PLATE ASSEMBLY Hermann Schmidt, 237 Burnham St., East Hartford, Conn. 06108 Filed Aug. 30, 1966, Ser. No. 576,092 US. Cl. 33 174 Int. Cl. G01b 5/20 5 Claims ABSTRACT OF THE DISCLOSURE This invention generally relates to precision tools and particularly concerns sine plates and the like usable, for example, in accurately holding a workpiece at a selected angle.
A primary object of the invention is to provide an improved sine plate particularly suited for quick and easy manufacture and assembly and which will provide long, reliable service.
Another object of the invention is to provide an improved sine plate capable of accurately setting sines of small angles at minute increments.
A further object of the invention is to provide a sine plate of the above described type :having an improved clamp for retaining the plates of the assembly in a desired angular relation and which is of durable, compact and economical construction particularly suited for quick attachment and release.
Other objects will be in part obvious and in part pointed out more in detail hereinafter.
The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth, and the scope of the application of which will be indicated in the appended claims.
In the drawing:
FIG. 1 is a side elevational view, partly broken away and partly exploded, showing a sine plate assembly constructed in accordance with the present invention; and
FIG. 2 is a front elevational view of the assembly of FIG. 1, exploded in part, partly broken away and partly in section.
Referring now to the drawing in detail, a preferred embodiment of a sine plate assembly of this invention is shown generally comprising a base member or plate upon which a top member or plate 12 is pivotally con nected adjacent its rear end 14, the top plate 12 being shown as having a plurality of openings 16. Plates 10 and 12 are preferably formed of hardened ground steel each having an upper face 18 and 20 with fine precision finished surfaces. The base plate 10 thus provides a flat master surface from which vertical measurements are taken in nited States Patent 0 accordance with conventional techniques by means of a precision gage block 21, or combination of gage blocks, and the top plate 12 provides an accurately fiat work support surface.
As best seen in FIG. 2, a front roll 22 and a pivot shaft 24 are spaced apart a preselected standard distance and secured in position, e.g., by screws, not shown, across a lower face 26 of the top plate 12 adjacent its front end 28 and rear end 14 respectively.
In accordance with one feature of the present invention, the longitudinal axes or center lines of the pivot shaft 24 and the front roll 22 are readily and precisely positioned parallel to one another in a common plane parallel to the finished upper faces 18 and 20 of plates 10 and 12 when the front roll 22 is in engagement with the base plate 10. This is accomplished by means of a pair of end bushings 32, 34 precisely located in a lateral recess 36 extending inwardly from opposite sides 38, 40 of the base plate 10-. Bushings 32, 34 are accurately formed cylinders having equal outside diameters greater than that of the pivot shaft 24, and the rear corners of the lower face 26 of the top plate '12 are shown cut away at 42 and 44 to provide sufiicient clearance for the enlarged end bushings 3'2, 34. An axial hole 46 (FIG. 2) is formed in each bushing for receiving a reduced end portion 48 at each end of the pivot shaft 24 whereby the same is supported for rotation within the bushings 32, 34 which are removably secured to the base plate 10 by suitable fasteners such as the machine screw shown at 50. By virtue of the above described structure, manufacture and assembly is significantly facilitated since close tolerances are readily held on bushings 32, 34 to ensure dimensional integrity and their enlarged size effects greater purchase for the screws 50 and increased strength of assembly.
In addition, the disclosed pivot arrangement is particularly suited to maintain the top plate 12 essentially free of lateral displacement during a work forming operation. Each end bushing 32, 34 preferably includes a pair of annular flat springs or wave Washers 52 seated against a shoulder 54 formed by an enlarged recess 56 at the outer end of each bushing 32, 34. The springs 52 are bottomed against the shoulder 54 and compressed by means of a retaining ring 58 firmly seated by a screw 60 threadably secured to the reduced end portion 48 of the pivot shaft 24. Upon adjustment of the screws 60 at opposite ends of the pivot shaft 24, oppositely directed axial spring forces are applied to the pivot shaft 24 whereby it is continuously balance-d under spring tension and maintained against axial displacement while yet allowing for the necessary movement between plates 10 and 12.
In this regard, it will be noted that if the plates 10 and 12 are disassembled for any reason, the top plate 12 may be readily reassembled in proper working condition in a minimum period of time requiring only a minimal degree of skill.
The pivot shaft 24 is thus quickly and accurately located and assembled for swinging movement of the top plate 12 toward and away from the base plate 10, and the top plate 12 may be angularly adjusted relative to the base plate 10 by positive contact between the front roll 22 and a gage block such as that illustrated at 21 positioned on the base plate 10. The size of the gage block is selected for whatever dimension is required to locate a workpiece at a desired angle on the top plate 12 as, e.g., in drilling, milling, surface grinding and similar work forming operations.
To set sines of small angles, the front roll 22 is shown as having opposite end portions 62, 64 of reduced diameter. The reduction in diameter of the front roll 22 is preferably exactly 0.400 inch to provide a 0.200 inch step on the front roll 22. The sine plate assembly of the invention is thus adapted for use with standard sets of gage blocks conventionally available in heights above 0.100 inch, typically at successive increments of 0.0001 inch in gage block height.
In the course of various machining operations, my tendency of the top plate 12 to be lifted from the gage block assembly is minimized by means of an improved clamp 66 provided in accordance with still another feature of the invention. Clamp 66 generally comprises a rigid, adjustable length fastener 68 having opposite end portions connected to upper and lower toggle yokes 70, 72 respectively having rearwardly projecting shank portions 74, 76 removably insertable into sockets 78, 80 formed in front ends 28, 82 of plates 12 and 10. The upper and lower toggle yokes 70, 72 respectively include a pivot pin 84, 86 rotatably supported between opposite legs of a generally U-shaped bracket portion 88, 90 attached at forward ends of their respective shank portions 74, 76.
In the preferred embodiment, fastener 68 is comprised of two separable parts including an internally threaded sleeve 92 fixed to pivot pin 86 of the lower toggle yoke 72, and a bolt 94 slidably rceived in an aperture of pivot pin 84 of the upper toggle yoke 70 for pivotal movement relative to the top plate 12.
In operation, shank portions 74, 76 of the clamp 66 are simply inserted into the sockets 78, 80, and the lower threaded end of the bolt 94 is secured in the sleeve 92 after the angular setting of plate 12 is properly adjusted relative to base plate 10. Bolt 94 is provided with an enlarged head 96, preferably slotted for receiving a setting instrument such as a screwdriver, not shown, whereupon the clamp 66 is readily tightened to draw the head 96 of the bolt 94 into engagement with pivot pin 84 of the upper toggle yoke, thereby to lock top plate 12 in position to provide the desired pressure on the gage block 21.
It is to be noted that a considerable mechanical ad vantage is provided by the described clamping arrangement wherein the holding force is applied on the front ends of the plates 10, 12 to more effectively resist any tendency of the front plate 12 being lifted away from the base plate 10. In addition, a set of bolts of varying length is provided to accommodate a full range of angular settings of the top plate 12, and the overall length of the fastener 68 may be preselected accordingly such that it is continuously positioned within an included angle formed by a lower face 100 of the base member and the upper face of the top plate 12, thereby eliminating any possibility of the clamp 66 interfering with a supporting surface for the assembly or with a workpiece being supported on the top plate 12.
The sine plate assembly of the present invention is of durable compact construction providing ease and economy in its manufacture and assembly while yet maintaining the required dimensional integrity. The disclosed structure also provides improved bearing support for the removable end bushings which as noted above are readily disassembled and reassembled by relatively unskilled labor to provide a proper pivotal connection between the movable plates. In addition, the above described structure is particularly suited to be quickly and easily set to securely hold a workpiece at a desired angle, even at small angles, without danger of the adjusted position of the assembly being disturbed during a machining operation. As will be ap parent to those skilled in the art, the features disclosed in the preferred embodiment could be readily incorporated in similar tools for obtaining compound angles.
As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention.
1. A sine plate assembly comprising a base member and a top member each having a socket formed in a front end thereof, said top member being pivotally connected adjacent its rear end to said base member, and an adjustable removable clamp including upper and lower toggle yokes each having a shank portion removably insorted into said sockets of said base member and said top member respectively, and a rigid adjustable length fastener having opposite end portions pivotally connected to said toggle yokes for precluding movement of said top member from a preselected angularly adjusted position with respect to said base member, said fastener being extensible to permit quick release of said clamp from said members.
2. The assembly of claim 1 wherein said clamp is continuously positioned within an included angle formed between a lower face of said base member and an upper face of said top member irrespective of said angularly adjusted position of said top member relative to said base member.
3. The assembly of claim 1 wherein said upper toggle yoke includes an apertured pivot pin, and wherein said adjustable length fastener comprises an internally threaded sleeve pivotally connected to said lower toggle yoke, and a bolt slidably received in said apertured pivot pin of said upper toggle yoke and threadably secured in said sleeve for selectively adjusting the length of said fastener, said bolt having a head at one end thereof engageable with said apertured pivot pin for precluding swinging movement of said top member away from said base memher.
4. A sine plate assembly comprisng a base plate and a top plate each having an upper face including a flat finished surface and a lower face, said upper face of said base plate having a lateral recess extending inwardly from opposite side edges thereof adjacent its rear end, a front roll and a pivot shaft spaced apart in parallel relation and secured to said lower face of said top plate adjacent front and rear ends thereof respectively, a pair of bushings coaxially mounted on said base plate and rotatably supporting said pivot shaft for swinging movement of said top plate toward and away from said base plate, said bushings each having an outside diameter of enlarged size relative to that of said pivot shaft and being positioned in said lateral recess of said base plate whereby center lines of said front roll and said pivot shaft are readily and precisely located in a common plane parallel to said flat finished surfaces of said plates when said front roll is in engagement with said base plate, said base plate and said top plate each having a socket formed in said front ends thereof, and an adjustable removable clamp comprising a rigid adjustable length fastener having opposite end portions and a pair of toggle yokes pivotally connected thereto, said toggle yokes each having a shank portion removably inserted into said front end sockets of said base plate and said top plate for precluding movement of said top plate from a preselected angularly adjusted position with respect to said base plate, said fastener being extensible to permit quick release of said clamp from said plates.
5. A sine plate assembly comprising a base member and a top member each having a socket formed in a front end thereof, said top member being pivotally connected adjacent its rear end to said base member, and an adjustable removable clamp including upper and lower toggle yokes each having a shank portion removably in- -serted into said socket of said base member and said top member, respectively, each also having a generally U- shaped bracket portion connected to each said shank portion, a rigid adjustable length fastener having opposite end portions, respectively, pivotally connected to said U-shaped bracket portions for precluding movement of said top member from a preselected angularly adjusted position with respect to said base member, said fastener being extensible to permit quick release of said clamp from said members, and a pivot pin mounted between opposite legs of each said U-shaped bracket portion providing the pivot connection between said opposite end portions of said fastener and said toggle yokes.
References Cited UNITED STATES PATENTS 2,733,702 2/1956 Barrett. 2,442,136 5/1948 Luther. 2,190,455 2/ 1940 McCollum et a1 21063 2,351,773 1/1944 Lovenston.
646,499 4/1900 Lodge.
10 LEONARD FORMAN, Primary Examiner.
S. STEPHAN, Assistant Examiner.