Bolts Having Indicators

1. Field of the Invention

The present invention relates to bolts and threaded studs. More particularly, the present invention relates to novel bolts and threaded studs having indicating means for indicating when the bolt or stud is fully engaged in a blind hole.

2. General Background of the Invention

High-pressure vessels use bolts to hold down covers. When studs or bolts are not fully engaged in their bolt holes, the structural integrity of high pressure dome tank cars is compromised. These bolts are usually screwed into "blind" holes (that is, holes which do not protrude through the wall of the vessel, but instead are closed at the bottom). Due to the high pressure of the contents of the vessels, it is desirable to have as many threads of the bolt as possible engaging the threads of the hole. Therefore, it is desirable to use as long a bolt as possible for a given hole. However, it is not easy to determine whether the bolt in a given hole is as long as possible.

The present invention was conceived to solve the problem of field inspection of high-pressure domes on railway tank cars. Currently, inspection of bolts and studs on these tank cars is done electronically using expensive equipment and skilled personnel.

The apparatus of the present invention solves the problems confronted in the art in a simple and straightforward manner. The present invention allows the inspection of studs and bolts to determine if they are fully engaged within a receptacle.

The present invention allows for the visual inspection of bolts and studs to determine if the bolts and studs are fully engaged. Visual inspection of bolts and studs is less costly than electronic inspection. Costs are reduced by eliminating the need for expensive electronic equipment and skilled personnel.

To allow an inspector to easily determine whether the bolt in a given hole is the longest bolt which could fit in that hole (i.e., to determine whether the bolt is fully engaged within the hole), the present inventor has added a movable pin in a bolt. This pin can freely move longitudinally in the bolt. If the pin protrudes out of bolt a predetermined distance after the bolt is screwed into a bolt hole, then the inspector knows that the bolt is fully engaged. If, on the other hand, the bolt is not fully engaged, the pin will not protrude the predetermined distance out of the bolt. A second embodiment of the invention is a stud having an indicator pin. In third and fourth embodiments, the bolts and studs have indicator pins including grease zerks and longitudinal bores. Grease can travel through the grease zerks and longitudinal bores. The grease zerks and longitudinal bores allow the holes to be filled with grease to prevent damage to the hole due to corrosion.

The visual inspection of bolts and studs of the present invention is accomplished by simply checking the indicator pin in the center of the bolt or stud. If the indicator is in the up position then the bolt or stud is fully engaged. If the indicator is not in the up position then the bolt or stud should be checked.

The present invention could prevent many leaks and accidents that occur due to the improper tightening of pressure domes.

The present invention can be used in any industry that desires a simple and safe way to check bolts and studs for full engagement of threads in a blind receptacle.

The concept of the "Direct View".TM. indicator studs and bolts is to allow an inspector to make a visual inspection to determine that the bolt or stud is fully engaged with the receptacle (bottomed out in the hole). The "Direct View".TM. indicator studs and bolt of the present invention are equipped with an indicator in the center of the stud or bolt that rises, for example, 1/8" to 3/16" when the bolt or stud has bottomed out in the hole. If for some reason the bolt or stud has not bottomed out, the indicator will be flush with the top of the bolt or stud (or at least not up the full, predetermined amount). The inspector then will know that it should be checked.

The studs and bolts of the present invention can be used in any application where visual inspection is needed for added safety.

The studs and bolts can be coded for length. The receptacle can have a corresponding code for easy matching.

The indicators do not weaken the tensile strength of the bolts or studs in which they are installed.

The bolts and studs of the present invention are applicable wherever direct view inspection would be an assist to safety.

The indicator bolts and studs of the present invention allow an inspector to determine if the bolt or stud is fully engaged in the receptacle by checking if the pin is in the up or down position. If the pin is in the up position and the inspector wants to check the bolt or stud engagement he need only lightly tap the pin. If the pin remains in the up position he can be certain that the threads are fully engaged. If, on the other hand, the pin moves downward, then the inspector knows that the bolt or stud is not fully engaged.

The studs and bolts of the present invention have a simple but effective means for determining that a stud or bolt has fully engaged the threads within its corresponding bolt hole. Inspection is quick and easy, just requiring a visual and manual check of the indicator pin. If the pin is in the full up position and cannot be moved either up or down, then the stud or bolt is fully engaged in its bolt hole (the bottom of the hole will prevent downward travel of the pin and the upper end of the larger diameter portion of the bore in which the indicator pin is situated will prevent upward travel of the pin when the bolt or stud is fully engaged).

The present invention provides simple mechanical indication of the condition of a stud or bolt. It eliminates the need for costly inspection equipment. It makes inspection quick and less expensive. It reduces maintenance time.

It is an object of the present invention to provide a bolt having means to allow an inspector to quickly tell whether the bolt is the longest bolt which would fit in a given hole and whether the bolt is seated properly.

It is a further object of the present invention to provide a threaded stud having means to allow an inspector to quickly tell whether the stud is seated properly.

It is another object of the present invention to provide bolts and threaded stud having indicator pins with incorporated grease zerks.

For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:

FIG. 1 is an exploded, cross-sectional view of a first embodiment of the apparatus of the present invention;

FIG. 2 is a cross-sectional view of a bolt of the present invention prior to engagement in a blind hole;

FIG. 3 shows the bolt of FIG. 1 fully engaged in a blind bolt hole;

FIG. 4 shows the bolts and studs of the preferred embodiment of the present invention in various degrees of engagement in blind bolt holes, with part of the bolt shafts being cut away to show the indicator pins therein;

FIG. 5 shows an embodiment of the present invention fully engaged in a blind bolt hole;

FIG. 6 is a view similar that of FIG. 5 but without full engagement of the threads of the hole with those of the bolt;

FIGS. 7 and 8 are similar to FIGS. 5 and 6, but instead show threaded studs;

FIGS. 9-11 show various stages of engagement of a threaded stud of the present invention and a blind bolt hole.

PARTS LIST:

The following is a list of suitable parts and materials for the various elements of the preferred embodiment of the present invention.

10 bolt of the preferred embodiment of the present invention

11 indicator pin in bolt 10

20 bolt

21 indicator pin in bolt 20

22 stud

23 nut

24 grease zerks

25 head of bolt 20

26 threaded part of shaft 28

27 indicator pin in stud 22

28 shaft of bolt 20

29 longitudinal bore in indicator pins 21

30 cover

31 blind hole in wall 39

32 blind hole in wall 39

33 blind hole in wall 39

34 blind hole in wall 39

35 hole in cover 30

36 hole in cover 30

37 hole in cover 30

38 hole in cover 30

39 wall of a pressure vessel

40 threaded stud

41 indicator pin in threaded stud 40

42 nuts

46 threaded portion of shaft 48

47 second end of stud 40

48 shaft of stud 40

49 first end of stud 40

50 bolt

55 head of bolt 50

56 threads of shaft 58

57 second end of bolt 50

58 shaft of bolt 50

59 first end of bolt 50

60 longitudinally extending bore in bolt 50

61 first, smaller diameter portion of bore 60

62 second, larger diameter portion of bore 60

70 indicator pin of bolt 50

71 first, smaller diameter portion of pin 70

72 second, larger diameter portion of pin 70

80 blind bolt hole

81 threads of bolt hole 80

82 first, open end of hole 80

83 second, closed end of hole 80

90 interior of vessel into which blind hole 80 protrudes

100 indicator stud

101 threaded portion of stud 100

102 unthreaded bottom portion of stud 100

103 indicator pin in stud 100

105 blind hole

140 threaded stud

141 indicator pin in threaded stud 140

146 threaded portion of shaft 148

147 second end of stud 140

148 shaft of stud 140

149 first end of stud 140

FIGS. 1 through 3 show the basic functioning of the threaded fasteners of the present invention.

FIGS. 1-3 show a bolt 50 and a blind bolt hole 80. Bolt 50 has a first end 59 and a second end 57. Adjacent the first end 59 of bolt 50 is a head 55 for turning the bolt. There is a threaded shaft 58 between head 55 and the second end 57. Shaft 58 has threads 56 which engage threads 81 of bolt hole 80.

Bolt 50 has a longitudinally extending bore 60 in the center thereof. Bore 60 has a first, smaller diameter portion 61 and a second, larger diameter portion 62. Slidingly received in bore 60 is an indicator pin 70. Indicator pin 70 has a first, smaller diameter portion 71 and a second, larger diameter portion 72.

Blind bolt hole 80 protrudes into the interior 90 of a pressure vessel 91. Blind hole 80 has a first, open end 82 and a second, closed end 83. When bolt 50 is properly engaged in hole 80, and the second end 57 of bolt 50 is bottomed out against the second, closed end 83 of bolt hole 80, indicator pin 70 protrudes a predetermined distance (for example, 1/8") above the first end 59 of bolt 50.

Having an indicator pin 70 of two different diameters prevents the pin from being removable when bolt 50 is engaged in hole 80.

FIG. 4 shows bolts 10 and 110 and studs 40 and 140 being used to hold down a cover 30 on a wall of a pressure vessel. Stud 40 passes through hole 35 in cover 30 and engages blind hole 31 of wall 39. Bolt 10 passes through hole 37 in cover 30 and engages blind hole 33 of wall 39. Bolt 110 passes through hole 38 in cover 30 and engages blind hole 34 of wall 39.

Bolt 10 shown in FIG. 4 includes a movable pin 11. Pin 11 can freely move up and down longitudinally in bolt 10. If pin 11 protrudes out of bolt 10 a predetermined distance after bolt 10 is screwed into the bolt hole 33, then the inspector knows that bolt 10 is fully engaged (see FIG. 4). If, on the other hand, the bolt is not fully engaged, the pin will not protrude the predetermined distance out of the bolt (see pin 111 in bolt 110 in FIG. 4). As in bolt 50, bolt 10 has a central longitudinal bore having two different diameters and like indicator pin 70, indicator pin 11 has a smaller diameter upper portion and a larger diameter upper portion to prevent pin 11 from being removed once bolt 10 is engaged in hole 33.

Nuts 42 are used to insert studs 40 and 140 into threaded blind holes 31 and 32. Stud 40 includes a shaft 48 having a threaded portion 46. Stud 40 has a first end 49 and a second end 47. Indicator pin 41 can be identical to indicator pin 11 except as to its length (indicator pin 41 is longer). Threaded stud 40 is properly engaged in hole 31, as indicated in FIG. 4. The second end 47 of stud 40 is bottomed out against the bottom end of hole 31, and pin 41 is protruding a predetermined distance out of the first end 49 of stud 40.

On the other hand, threaded stud 140 is not properly engaged in hole 32. As can be seen, threaded portion 146 of shaft 148 does not engage all of the threads of hole 32. The second end 147 of stud 140 is not bottomed out against the bottom of hole 32, and thus indicator pin 141 does not protrude a predetermined distance above the first end 149 of stud 140.

FIGS. 5-8 show bolts 20 and studs 22 having indicator pins including grease zerks 24. These grease zerks 24 allow the holes to be filled with grease to prevent damage to the hole due to corrosion. The indicator pins (21 and 27) shown in FIGS. 5-8 are similar to indicator pin 11, but include a grease zerk 24 at the first end thereof and include a longitudinal bore in the center thereof. Longitudinal bore 29 of indicator pin 21 allows grease to flow from a grease gun through grease zerk 24 and out of the second end of the indicator pin 21 into the hole in which bolt 20 is engaged.

Bolt 20 has a head 25 at a first end thereof, a shaft 28 having a threaded part 26, and an indicator pin 21 in a longitudinal bore similar to bore 60 shown in FIG. 1.

Stud 22 works in a similar manner to that of bolt 20, and includes an indicator pin 27 the same in all respects to indicator pin 21 except that indicator pin 27 is longer. Nut 23 is used to turn stud 22.

FIGS. 9-11 show an indicator stud 100 of the present invention. Indicator stud includes a threaded portion 101 and an unthreaded bottom portion 102. There is an indicator pin 103 in stud 100.

First stud 100 is threaded in the blind bolt hole 105. The indicator pin 103 rises as the stud 100 reaches the bottom of hole 105 (FIG. 10). When the stud 100 is tight, and the indicator pin 103 is in its full up position, and pin 103 cannot be moved either up or down, then the stud is fully engaged in the hole.

As can be seen in the drawing figures, the indicator pins do not impede full engagement of the threads of the threaded openings with the threads of the threaded fasteners. Also, as can be seen in the drawing figures, the indicator pins are longer than the shafts.

A 11/8"-7nc.times.41/2" L7 double end stud was tested and found to have a tensile strength of 131 KSI, which exceeds ASTM requirements of minimum 125 KSI for ASTM A320 grade.

While some of the drawings herein show studs or bolts fully engaged in blind holes without anything in between the top of the bolt and the top of the hole, normally the bolts or studs would be used to hold down a cover, as shown in FIG. 4. In such a case, of course, the bolt would be inserted in a hole in the cover before being inserted in the blind hole.

The studs and bolts of the present invention can be made of materials, such as stainless steel, which are normally used for studs and bolts.

Bolts 10, 20, and 50, and threaded stud 40 can be considered "bolt means". Shafts 28, 48, and 58 can be considered "shaft means". Heads 25 and 55, for example, can be considered "head means".

The present inventor contemplates using the indicator pins of the present invention with all types of studs and bolts, including re-threader studs and bolts (that is, studs and bolts which cut new threads into a stripped hole when they are inserted into the hole).

The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.