UNITED STATES PATENT OFFICE
SPECIAL LOCK SCREW
Richard La Vern Kindsvatter, Hagerstown, Md.,
assignor to Hagerstown Engineering Company,
.Inc., Hagerstown, Md., a corporation of Mary-
Application August 29,1947, Serial No, 771,315
6 Claims. (CI. 287—52.08)
The present invention relates to a special Jock screw and is particularly adapted for securing couplings, gears, pulleys, and the like to a shaft member although the principles of the invention may be applicable to other uses, and the lock 5 screw may be employed in general where various elements are capable of being held together by a set screw or similar holding means. Regardless, however, of the /specific use to which the .lock screw is put, the essential features of the inven- 10 tion are at all times -preserved.
One of the objects of the invention is the incorporation of both the principles of a standard set screw and a tapered pin in a novel locking combination. 15
Another object is to provide a-new and efficient method for removing the pin at any time the need should arise.
Still another object is to provide an improved method of installing or applying the lock screw 20 to the elements which are to be locked.
A further object is to provide a lock screw which may be practical in its application and simple and economical in its construction.
While several objects of the invention have 25 been specifically-pointed out, other objects and advantages-will also be apparent as the nature and purpose of the invention are more fully described in the following specification and shown in the accompanying drawings ,in which: 30
Figure 1 is an exploded view of the improved lock screw.
Figure .2 is a view of a pulley secured to a fragmentary portion of a shaft having parts of the pulley and shaft broken away to illustrate the 35 manner in which the lock screw is used.
Figure .3 is an enlarged fragmentary sectional view similar to that shown in Figure 2.
Figure 4 is a top -plan view of the screw.
Figure 5 is a view of a special tool for locking 4.9 the screw and pin elements together.
Figure 6 is a view similar to Figure 5 showing the manner in which the pin is locked within the set screw.
Figure 7 is an inverted plan view of the tool as ±§ shown in Figures 5 and 6.
Figure 8 is a fragmentary view in elevation of a modified form of tool.
Figure 9 is an inverted plan view of the modified form of tool, as shown in Figure 8. go
Figure 10 is a modified form of pin.
Figure 11 is a view similar to Figure 3, showing the detail manner in which the pip and set screw are assembled.
Figure 12 is a view similar t0 that ;shgwn jn 65
Figure 2 illustrating one of the uses to which the special lock screw is put.
Referring to the drawings in which like numerals are used to represent similar parts throughout the several views, the improved lock screw, comprises principally the novel combination of a set screw member 10 and a tapered pin 12. .The screw .is preferably provided with a hexagonal recess 10' for receiving a wrench, or other means, for rotating the screw. However, the recess may be of any desired form, or the screw may be provided with a head, slot, or in other conventional form for receiving a wrench or similar tool for rotating the same. Extending downwardly from the bottom of the recess ID' and through the screw IS is a gradually tapered aperture 10" which taper is of substantially the same size and taper as the upper end portion 12" of the .pin. As the pin is received Within .the aperture 10" of the screw, the upper portion of .the pin is of such diameter as to provide a. driving, fit within the aperture 10" which will provide sufficient friction between the screw member and the pin to prevent the pin from moving outwardly through the screw after it has once .been driven in place. The relatively long gradual taper of both the aperture 10" and the pin 12 are. such that after the pin has been firmly driven .into place, the screw and pin become, for all practical purposes, locked together.
For locking a pair of members, such as a pulley 1.3 to a shaft, by use of the special lock screw, .one of the members 14 is drilled and tapped as shown at 14' in Figure 3. A screw 13, which is of the proper size and also threaded, is screwed into the threaded aperture 14' until the inner end of -the screw comes to rest firmly upon a second member !G. Using the aperture J,P" of the screw as a guide, the second member jS is drilled to receive the inner end 12' of the pin. The aperture 16' is preferably of the same long gradual taper as the aperture within the aperture within the screw. After the aperture 16' has been drilled and tapered to the proper size, the pin is then placed within the upper end of the set screw and driven through the aperture 10" to a point where the pin becomes securely seated within both the tapered portion of the screw and the aperture 16' of the shaft element f6. The head J2" of the pin, when in seated position, should be slightly below the bottom of the recess 10'. This will assure ample space for the wrench, or other means for rotating the screw.
A modified form of the pin is shown in Figures