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Publication numberUS3717794 A
Publication typeGrant
Publication dateFeb 20, 1973
Filing dateMar 8, 1971
Priority dateMar 8, 1971
Publication numberUS 3717794 A, US 3717794A, US-A-3717794, US3717794 A, US3717794A
InventorsHiggins R, Yates P
Original AssigneeExplosives Corp America
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Blasting device
US 3717794 A
Abstract
A blasting device adapted to be carried and operated within a person's hand, the device comprising a small rectangular case having on its top surface an operating switch, an indicating light and a pair of binding posts. The case contains a pair of batteries and a capacitor. The switch is movable to a first position to connect the indicating light and the capacitor in parallel relationship to the batteries so as to charge the capacitor, with the indicating light being lit while the batteries are imposing a voltage across the capacitor, and the switch is movable to a second detonating position in which the charge of the capacitor is imposed across the binding posts so that when leads from the binding posts are connected to a detonator with explosive charge, the explosive is detonated.
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Description  (OCR text may contain errors)

United States Patent 1 1 Yates et al.

1 1 Feb. 20, 1973 [54] BLASTING DEVICE [73] Assignee: Explosive Corporation of America,

lssaquah, Wash.

[22] Filed: March 8, 1971 [21] Appl. No.: 121,690

[52] US. Cl. ..3l7/80, 89/1.5, 102/70.2,

317/95, 320/1 [51] Int. Cl. ..F23g 7/02 [58] Field of Search ..3l7/80, 95, 79, 96; 320/1;

[56] References Cited UNITED STATES PATENTS 11/1961 Wallack et a1 ..3l7/80 7/1969 Zingg et a1 ..3 17/80 X Primary Examiner-Volodymyr Y. Mayewsky Attorney-Graybeal, Cole 8L Bernard [57] ABSTRACT A blasting device adapted to be carried and operated within a person's hand, the device comprising a small rectangular case having on its top surface an operating switch, an indicating light and a pair of binding posts. The case contains a pair of batteries and a capacitor. The switch is movable to a first position to connect the indicating light and the capacitor in parallel relationship to the batteries so as to charge the capacitor, with the indicating light being lit while the batteries are imposing a voltage across the capacitor, and the switch is movable to a second detonating position in which the charge of the capacitor is imposed across the binding posts so that when leads from the binding posts are connected to a detonator with explosive charge, the explosive is detonated.

18 Claims, 6 Drawing Figures PATENTEUFEBZOlUYS sum 1 0r 2 INVENTOR. g. YATES PATRICK ROBERT n: rillL ATTORNEYS PATENTED 3,717. 794

SHEET 2 OF 2 I 28p 44 'Tkh36 65 142 i) v 7 6@ 64 ATTORNEYS BLASTING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a blasting device to supply an electric charge to ignite an explosive charge.

2. Description of the Prior Art In general, there are three types of blasting machines:

a. Those using an alternator b. Piezo-electric type machines c. Battery/capacitor blasting machines In the blasting machines having an alternator, generally the alternator develops a voltage which is either transmitted directly to the detonator of the explosive charge, or is transmitted through a rectifying device to charge a capacitor, which in turn is used to ignite the detonator. This arrangement makes the machine unavoidably complex and expensive, and of a bulk that it cannot conveniently be carried within a persons hand and operated from that position.

The piezo-electric blasting machines are operated by impacting a piezo-electric device with sufficient energy to generate the ignitingcharge. Such devices have been limited primarily to military application.

The battery/capacitor blasting machines employ the principle of utilizing one or. more batteries to charge a capacitor, which in turn is dischargedto ignite the explosive. However, in these prior art devices, the selection and arrangement, of components has been such j that these devicesare not readily adapted for use in a hand-carried type blasting machine.

SUMMARY OF THE INVENTION The present invention provides a blasting device having a small rectangular casewhichcan be held'within a person 's hand. The arrangement is such that on the top of the case there are a pair of binding posts, an indicating light, and. a thumb-actuated switch having a first charging position and a secondigniting position. The case contains an electrolytic capacitor andapair of batteries. The two batteriesare themselves arranged in series and are further arranged to be connected. in parallel relationship with the capacitor and the indicatinglight. The switch is adouble pole, double throw switch having two operating positions and a relaxed nocontact position. In I its first operating position the switch closes two circuit loops, one loop being from one battery terminal through a diode, thence through both wipers of the switch and throughthe indicating light to the opposite terminal of the battery set, and the other loop being from the battery set, through the diode through one wiper arm and through the capacitor to the other end of the batteries. In its second operating position the switch connects one plate of the capacitor in a parallel path through both wipers to one binding post, with the other capacitor plate being connected to the other binding post, so as to impose thecapacitor charge across the binding posts to detonate the explo- SIVC.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the blasting device of the present invention;

FIG. 2 is an end elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a side elevational view thereof, with the case of the device shown in section;

FIG. 5 is a sectional view taken on line 5 5 of FIG. 4, and

FIG. 6 is a circuit diagram of the blasting device of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The blasting device of the present invention comprises a case 10 comprising a top wall 12, bottom wall 14, two sidewalls l6 and two end walls a front end wall 18a and a rear end-wall 18b. For convenience of manufacture and assembly the case 10 is made up of upper and lower sections 20 and 22, respectively, with these two sections being joined together at a juncture 24. On one end of the top wall 12 there is mounted a switch lever 26, and at the opposite end of the top wall 12 are a pair of binding posts 28. Mounted to the center position of the top wall 12 between the lever 26 and binding posts 28 is an indicating light 30.

Upstanding from the top wall 12 as vertical extensions of the two sidewalls 16 are a pair of guard plates 32 positioned on opposite sides of the switch level 26. so as to protect the lever 26 from accidental contact with any object. In describing the apparatus of the present invention the term forward will be used to designate that portion of the apparatus toward the binding posts 28 and the term rear will denote that portion of the apparatus towardthe switch lever 26.

The case 10 is so arranged that it can conveniently be carried within the hand. To operate this blasting device, it is grasped inthe hand with the fingers ofthe hand reaching around the front end wall 18a and the heel of the hand bearing against the rear end wall 18b, with the palm of the hand adjacent one of the sidewalls 16, depending upon whether the device is grasped in the right or left hand. When so held, the persons thumb of the holding hand is adjacentthe switch lever 26. The switch lever 26 has an upright rest position, which is the inoperative position, andthe lever 26 can be moved rearwardly to a charging position and moved forwardly to a firing'position.

Mounted in the forward portion of the case 10 is an electrolytic capacitor 34, which is characterized in that it has a relatively high charge to volume ratio and will double throw switch 38 which is operated by the switch I lever 26.

The blasting device's circuitry, generally designated 40, ismounted in the case 10 above the batteries 36. Thiscircuitry 40 is encased in a resin which provides water-proofing for the circuitry. With reference to the circuit diagram shown in FIG. 6, it can be seen that the two batteries 36 are connected in series with the negative output terminal of the battery set 36 being connected to one of the binding posts 28a and to the negative plate 42'of the capacitor 34. Also, the negative terminal of the battery is connected in series through a voltage reducing resistor 44, through the indicating light 30 to a first stationary contact 46 of the switch 38. The positive output terminal of the battery set 36 is connected in series with a diode 48 to a second stationary contact 50 of the switch 38.

The positive plate 52 of the capacitor 34 is connected directly to both a first and second wiper or switching element which are numbered, respectively, 54 and 56. The switch 38 also has a second set of stationary contacts, third contact 58 and a fourth contact 60. Both of these contacts 58 and'60 are connected directly to the second binding post 28b. In operating condition, the two binding posts 28a and 28b are connected to an igniter 62 which in turn is arranged to detonate an explosive charge 64. There is a high resistance resistor 65 connected in series with the capacitor 34 to dissipate a charge on the capacitor over several minutes in the event that the capacitor 34 is charged and then not fired.

To correlate the operation of the switch 38 to the switch lever 26, when the lever 26 is upright in its normal rest position as shown in the accompanying drawings, the two switching elements 54 and 56 are in the position shown in FIG. 6 whereby they are connected only to the positive terminal of the capacitor 34 and connect to none of the stationary contacts 46, 50, 58 and 60. When the lever 26 is moved rearwardly, the two switching elements 54 and 65 are, as shown in FIG. 6, moved to the left with the element 54 engaging the stationary contact 46 and the element 56 engaging the contact 50. This is the charging position of the switch 38. When the switch lever 26 is moved forwardly, this moves the switching elements 54 and 56, as shown in FIG. 6, to the right, where they make contact with the two contacts 58 and 60. This is the firing position of the switch 38.

For convenience a belt clip 66 is connected to the bottom of the case 10 and hasan upstanding clip arm 68 bearing against one case sidewall 16. Thus when the clip 68 engages a persons belt, the case 10 is inverted with the lever 26 in adownwardly extending protected position. Also, there is a carrying ring 70 on the bottom of the case 10, which also causes the case 10 to be carried in inverted position.

To describe the operation of the present invention, let it be assumed that the blasting device is connected by means of its binding posts 28 to the igniter 62 of the explosive charge 64. To charge the capacitor 34, the person grasps the case 10 in the aforesaid manner and with this thumb moves the lever 26 rearwardly to its charging position. It should be noted that this rearward movement makes the indicating light 30 readily visible to determine if the device is properly charging. When the lever 26 is so moved r'earwardly, the switching elements 54 and 56 make contact with the two contacts 46 and 50. There is a flow of current in a first circuit loop from the battery 36 through the diode 48, through the second switching element 56, and the capacitor 34 back to the battery set 36. There is also a flow of current in a second circuit loop from the battery set 36 through the diode 48, through the second switching element 56, thence through the first switching element 54 and through the lamp 30 and resistor 44 back to the battery set 36. The initial surge of current is largely to charge the capacitor 34, and it is at the time when the capacitor 34 is nearly completely charged that there is sufficient current to cause the light 30 to be lit. Of course, when there is already a charge on the capacitor 34 and the switch 38 is moved to its charging position, the light 30 will immediately become lit. With the light 30 so lit, the operator knows that the capacitor 34 is sufficiently charged so that the blasting device can be fired to detonate the explosive 64. It should be noted that the light 30 will not be lit unless the switching element 56 is properly making contact, thus insuring that the capacitor 34 is properly charged.

To fire the explosive 64, the switch lever 26 is moved forwardly, which in turn moves the switching elements 54 and 56, as shown in FIG. 6, to the right to engage the contacts 58 and 60. This causes the positive plate 52 of the capacitor 34 to be connected in parallel through both switching elements 54 and 56 to the binding post 28b. With the negative terminal 42 already in contact with the other binding post 28a, the charge imposed across the two posts 28a and 28b is in turn passed to the igniter 62 to detonate the explosive 64.

What is claimed is:

l. A blasting device adapted to be carried within a persons hand and operated in that position, said device comprising:

a. a case having top, bottom and sidewalls, and having a forward end portion and a rear end portion,

b. binding posts at the forward end portion of said case for attachment to an explosive charge,

c. a charging indicator at the top of said case,

d. battery means mounted in said case,

e. a capacitor mounted in said case,

f. circuit means arranged to connect said battery to said capacitor and to said indicator, and also to connect said capacitor to said binding posts,

g. a switch mounted to said case, and having a rest position, a charging position in which current is supplied through said circuit means to said indicator and to said capacitor, and having a firing position whereby said capacitor is attached through said circuit means to said binding posts,

. said switch having an actuating element mounted to the upper rear portion of said case, whereby when said case is grasped in a person s hand with a persons fingers engaging the front portion of the case and a persons heel of his hand grasping the rear portion of the case, said switch actuating element can be operated by the person s thumb of the hand grasping the case, and

i. suitable electrical insulation being provided to prevent undesired electrical shorting of said above recited components.

2. The apparatus as recited in claim 1, wherein said charging indicator is a light arranged in parallel relationship with the capacitor.

3. The apparatus as recited in claim 1, wherein said actuating element is an upright lever having a rearward position which is a charging position, a forward position which is a firing position, and an intermediate position which is a rest position.

4. The apparatus as recited in claim 3, wherein said case is provided with two upwardly extending guard platespositioned on opposite sides of said actuating element.

5. The apparatus as recited in claim 4, wherein there is carrying means mounted to the lower portion of said case.

6. The apparatus as recited in claim 5, wherein said carrying means comprises a belt clip mounted to the bottom of said case and comprising an upwardly extending clip element along one side of said case,

whereby when said case is carried on a belt, the actuatin g element is on the downward side of the case.

7. The apparatus as recited in claim 5, wherein said carrying means comprises a carrying ring mounted to the bottom of said'case, whereby when said case is carried by said ring, the actuating element is on the downward side of the case.

8. The apparatus as recited in claim 1, wherein said switch means comprises first. and second movable switch elements and first and "second stationary contacts, said switch elements and said contacts being arranged that with the switch in its charging position, the first element engages the first contact and the second element engages the second contact, thereby forming a first circuit loop from the battery means through the indicating means, through the two switch elements in series and back to said battery means, and forming a second circuit loop from said battery means through said capacitor, through at least one of said switch elements and back to said battery means.

9. The apparatus as recited in claim 8, wherein said switch elements are arranged to be in constant contact with said capacitor.

10. The apparatus as recited in claim 9, wherein there is other stationary contact means arranged to engage said switch elements when said switch is in its firing position, so that said capacitor is connected across said binding posts to impose a charge across said posts.

11, The apparatus as recited in claim 10, wherein said switch is a double pole, double throw switch having a ho-contact rest position, with said switching elements being wipers of theswitch, said first and second contacts being a first set of stationary contacts, and said other contact means being thirdand fourth stationary contacts.

12. The apparatus as recited in claim 8, wherein said capacitor is an electrolytic capacitor arranged to be charged in one direction, and there is a diode in said second circuit loop to prevent opposite charging of said capacitor.

13. A blasting device, comprising:

a. a case,

b. binding posts mounted to said case,

. a charging indicator mounted to said case,

. battery means mounted within said case,

a capacitor mounted within said case,

. circuit means mounted within said case and arranged to connect said battery to said capacitor and said indicator and also arranged to connect said capacitor to said binding posts,

g. switch means mounted to said case and having a rest position, a charging position in whichcurrent is supplied tojsaid indicator and to said capacitor, and a firing position, whereby said capacitor is connected to said binding posts so as to impose a charge across said posts, said switch means comprising first and second movable switch elements and first and second stationary contacts, said switch elements and said contacts being so arranged that with the switch in its charging position, the first element engages the first contact and the second element engages the second contact, thereby forming a first circuit loop from the battery means through the indicating means, through the two switch elements in series and back to said battery means, and forming a second circuit loop from said battery means through said capacitor, through at least one of said switch elements and back to said battery means, and

h. suitable electrical insulation being provided to prevent undesired electrical shorting of said above I recited components.

14. The apparatus'as recited in claim 13, wherein said switch elements are arranged to be in constant contact with said capacitor.

15. The apparatus as recited in claim 14, wherein there is other stationary contact means arranged to engage said switch elements when said switch is in its firing position, so that said capacitor is connected across said binding posts to impose a charge across said posts.

16. The apparatus as recited in claim 15, wherein said switch is a double pole, double throw switch having a no-contact rest position, with said switching elements being wipers of the switch, said first and second contacts being a first set of stationary contacts, and said other contact means being third and fourth stationary contacts.

17. The apparatus as recited in claim 16, wherein said capacitor is an electrolytic capacitor arranged to be charged in one direction, and there is a diode in said second circuit loop to prevent opposite charging of said capacitor.

18. A blasting device, comprising:

a. a case, i v

b. binding posts mounted to said case,

0. a charging indicator mounted to said case,

d. battery means mounted within said case, said battery means having a first output terminal and a second output terminal,

e. a capacitor mounted within said case, said capacitor having a first plate and a second plate,

f. said first output terminal being connected to the first plate of the capacitor, also connected to one of said binding posts, and further connected to said charging indicator,

g. switch means mounted to said case and having a rest position, a charging position in which current is supplied to said indicator and to said capacitor, and a firing position, whereby said capacitor is connected to said binding posts so as to impose a charge across the posts, said switch means being a double pole, double throw switch having a no-contact rest position, said switch comprising two wipers, a first set of first and second stationary contacts and a second set of third and fourth stationary contacts,

. the other output of said battery being connected in series. through a diode to said second stationary contact, said charging indicator being connected to said first stationary contact and in series between said first stationary contact and the first output terminal of the battery,

i. the second plate of the capacitor being in constant contact with both wipers of said switch,

j. said third and fourth stationary contacts being connected to said second binding post,

k. said first and second wipers, with said switch in its charging position, being in engagement with,

respectively, said first and second stationary con- 1. said wiper arms further arranged so that with said switch in its firing position, said first and second wipers are in engagement with, respectively, said third and fourth contacts, so as to connect said second plate of said capacitor through said wipers in parallel to said second binding post, and

m. suitable electrical insulation being provided to prevent undesired electrical shorting of said above recited components.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2395600 *Apr 14, 1943Feb 26, 1946Louis WeisglassMeans to ignite photographic flash lamps
US2844081 *Apr 2, 1953Jul 22, 1958Agfa AgElectrical flashlight device with condenser ignition
US2912902 *Jun 20, 1958Nov 17, 1959Nessler Thomas GExplosive powered bomb release unit
US3011096 *Nov 9, 1955Nov 28, 1961Perdreaux Jr Rene JElectrical timing circuit
US3141114 *Mar 28, 1962Jul 14, 1964Vibration Measurement EngineerBlasting machine
US3457431 *Feb 20, 1968Jul 22, 1969Dow Chemical CoTime-delayed control device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4089035 *Feb 4, 1976May 9, 1978Tyler Holding CompanyHand-held detonator
US5341742 *Dec 16, 1991Aug 30, 1994Eev LimitedFiring arrangements
US5367428 *Dec 18, 1992Nov 22, 1994Raymond Engineering Inc.Integrated safety discharge module
WO1992010718A1 *Dec 16, 1991Jun 25, 1992Eev LimitedFiring arrangements
WO1993023718A2 *May 18, 1993Nov 25, 1993Explosive Developments LimitedElectric initiating means for a shock tube
WO1993023718A3 *May 18, 1993Jan 20, 1994Explosive Dev LtdElectric initiating means for a shock tube
Classifications
U.S. Classification361/251, 361/248
International ClassificationF42D1/045, F42D1/00
Cooperative ClassificationF42D1/045
European ClassificationF42D1/045