US1990772A - Spark plug tester - Google Patents

Description

Feb. 12, 1935. w BORCHERT ET AL 1,990,772

SPARK PLUG TESTER Filed Jan. 9, 1933 4 Sheets-Sheet 1 III IIIIIIIIN Feb. 12, 1935. w BORCHERT ET AL 1,990,772

SPARK PLUG TESTER 4 Sheets-Sheet 2 Filed Jan. 9, 1955 Feb. 12, 1935.

w. BORCHERT ET AL SPARK PLUG TESTER Filed Jan. 9, 1933 4 Sheets-Sheet 5 Feb. 12, 1935.

w. BORCHERT El AL 1,990,772

SPARK PLUG TESTER Filed Jan. 9, 1955 4 Sheets-Sheet 4 F T 110 v 11 in the breaking of the glass of the case.

Patented F eb. 12, 1935 PATENT OFFICE SPARK PLUG TESTER William Borchert and Fred L. Borchert, Rockford, Ill.

Application January 9, 1933, Serial No. 650,774

6 Claims.

This invention relates to testing machines, and more specifically to mechanism for testing the firing capacity of spark plugs.

There has been known heretofore certain mechanisms designed to accomplish this purpose, but all of them have been open to more or less serious objection. In some of these machines a single large compression chamber has been employed having a series of threaded openings each designed to accommodate a different size of plug. In this construction it was necessary to screw the plug into the threaded opening with Sullicient tightness to prevent the escape of gas under the pressure used for testing. This necessitated the use of a wrench which frequently slips off the nut, breaking the porcelain of adjacent plugs. Furthermore, the tester is frequently used on the top of a glass show case, and the use of a heavy wrench in tightening the plugs commonly results Another objection to this type of construction lies in the fact that different sizes of holes are required to accommodate the dififerent sizes of spark plugs in common use. This means that it is necessary to plug all of the holes except the one in use, and, consequently, it usually requires the removal of one plug before the plug to be tested can be inserted. Sometimes it also involves the insertion of a plug in a hole employed for a previous test. This construction also involves the difficulty in keeping all of the holes air-tight to prevent the loss of pressure in the compression chamber.

In many of the prior art constructions air has been provided to the compression chamber from the usual air tanks of garages and the like, the air being supplied under pressure. The objection to this arrangement lies in the fact that it requires a permanent connection between the testing mechanism and the air line so that the testing mechanism is either fixed in place or movable only through a relatively small area, depending on whether the connection was made by means of pipes or flexible tubes. Furthermore, since the advent of low pressure tires, the air pressure carried in the usual tanks is too low for satisfactory operation of the testing mechanism which requires that the tanks be held at a considerably higher pressure than would otherwise be desirable.

A primary object of the invention is the provision of a self-contained testing unit which may be moved from place to place as the occasion demands, and requires no permanent or fixed connection.

Another object of the invention is to provide wherein handles and plug positioning mechanism operate in a substantially horizontal plane.

A still further object is the provision of pump. mechanismsuch that the power required to move the handles is substantially the same throughout its stroke to provide uniform and smooth operation.

Other objects and attendant advantages will become apparent to those skilled in the art from the following description. and the accompanying drawings in which-- Figure l is a side view of the tester showing the upper portion in elevation and the base in section;

Fig. 2 is a section on the line 2-2 of Figure 1;

Fig. 3 is a fragmentary top view of the battery holding means and bottom panel;

Fig. 4 is a section on the line 44 of Figure 1;

Fig. 5 is a vertical section, taken longitudinally through the upper portion of the tester;

Fig. 6 is a fragmentary side view of the cradle for holding the spark plug;

Fig. 7 is a section on. the line 7-7 of Fig. 5;

Fig. 8' is a section on the line 8-8 of Fig. 5;

Fig. 9 is a section on the line 99v of Figure 1;

Fig. 10 is a section substantially on the line 1010- of Figure 1;

Fig. 11. is afragmentary side view of a preferred embodiment of the invention;

Fig. 12 is a vertical section through the housing of the form shown in Fig. 11 showing the contents in elevation, and

Fig. 13' is a'fragmentary View showing the wiring: connections of the preferred form.

The invention contemplates a. construction having' a compression chamber and pump mechanism for developing air pressure within the compression chamber. Means are provided for indicating the pressure in the chamber. Likewise, relief mechanism is provided for relieving excessive pressure in the chamber, such as that which might be caused by an explosion therein; Novel means are provided for inserting the spark plug so that the spark gap rests within the compression chamber, and for holding the plug in this position. In order topass a'spark across. the spark gap of the plug to testthe same, means are provided for producing such a spark from dry cell batteries. The entire mechanism is so arranged as to constitute a testing unit, and the glass.

parts are so assembled as to give certain improved and beneficial results, a portion of which results are obtained solely through the space relationship of the parts.

Referring first to Figure 1, a housing 11 is ar: ranged to act as a base having a hollow interior 12 for the reception and support of electrical means presently to be more fully described. Feet '13 are fastened to the bottom side of the housing by means of screws 14, and may advantageously be of rubber or other resilient material toprovide a cushion support for the tester. A body, designated generally by the numeral 15, is secured to the top of the housing 11 by means of screws 16 or by other suitable means. In the present instance this consists of a platform 17 having a rearwardly extending arm 18 and'an upwardly extending cylinder and chamber portion 19 which are cast'integral in theform of a single piece. Formed inthe body portion 19 is a compression chamber 21 and a cylinder 22 connected'by means of a passageway 23 so that air may be passed from the cylinder into the compression chamber. A cylinder head 24 is positioned over the front end of the cylinder 22 by means of cap screws 25. The chamber 21 is formed with openings'on both the front and rear side of the portion 19. A bore 26 concentric with and somewhat larger than the chamber 21 is formed at the forward end of the chamber to receive an. observation window 27. The window 27 is secured in the bore 26 by means of a ring of rubber or other resilient material. This ring consists of a U-shaped circular piece of rubber having a portion 28 arranged to bear against the marginal edge of the window 27 and flanged portions 29 and 31 arranged to bear against the opposed sides of the window adjacent its periphery so as to provide a resilient mounting for the window. A retaining ring 32 is secured against thebody 15 by'means of screws 33, and'bears against the rubber ring to compress the ring and. hold the window tightly against the body, In this instance we have shown the window 27 as being of plate glass, but it may be made of any suitable transparent material, one such material being so-called shatter-proof or laminated The walls of the chamber 21 are provided with an outlet 34for the threaded reception of a pressure gauge 35 of conventional design, the

gauge being arranged to indicate the pressure in the chamber and calibrated to a suitable scale. The chamber 21 is also provided, with an opening 36 arranged for the'threaded reception of a relief valve 37 which may advantageously be of the type having a ball valve member 38 held in position against a suitable seat by means 'of a spring 39. This relief valve may be made to serve one or a combination of functions, depending upon the desires of the manufacturer. For example, it may be set to open at the predetermined pressure at which the test is to be carried on so that when air is injected into the compression chamber it will automatically open when the desired pressure is attained and thus automatically limit the pressure to the testing pressure. Under these circumstances, it will be seen that should an explosion occur inthe compression chamber, which might conceivably occurshould a plug be inserted therein covered with gasoline or other explosive fuel, the excessive pressure thus developed in the chamber would ,be relieved through the valve. On the other hand, the pressure gauge 35 may be relied upon solely for the purpose of indicating the testing pressure and n the relief valve set to open at a higher pressure to provide the necessary safety and thus insure against the eflects of an accidental explosion.

The body portion 19 is also provided with a bore 41 at the rear opening of the compression chamberr2l and concentric therewith for the reception of a gasket 42 of resilient material, prefas to receive the threaded portions of the spark plug within relatively close limits. Thus, through this arrangement the conventional spark plug, such as shown at 44 of the type commonly employed in automotive engines, may be inserted into the compression chamber with the threaded portion of the plug foremost, as shown in Fig. 5

'until the flange 45 of the plug comes into contact with the bushing 42. The flange is forced against the bushing with sufficient pressure to prevent the escape of air therebetween. In this man- 'ner the spark gap 46 of the plug is positioned within the compression chamber so that the performance of the plug under pressure may be observed through the window 27. Since spark plugs for automotive use vary to a certain degree in size, that is, the diameter of the threaded portion of the plug, the internal diameter of the gasket 42 is made of such size as to closely receive the larger of these plugs. In order to prepare the smaller sizes to be similarly tested by 'means of the same devices, a bushing 4'7 is provided and is threaded on its inner surface for reception on the threaded portion of the spark size as to bring the threaded portion of the smaller plugs to the same apparent diameter as plug, as shown in Fig. 8. This bushing is of such the larger plug. It will be seen that any number of these bushings may be provided to accommodate any smaller size of plug to the testing mechanism. The threads on the inner side of the bushing are so made that the bushing may be turned onto and off from the plug solely by means of the fingers, so that the testing operations are not materially retarded by the necessity for using the bushing. In order to position a spark plugv with the spark gap in the compression chamber and the flange firmly against the gasket, a cradle43 is employed having a notched upper surface 49 and The forward side of the cradle is provided with-a face 52 arranged to be brought against the metal portion or nut :53 of the-plug; Thus, when the cradle is moved forward, the

reinforcing 51..

surface 52 of the cradlebears against the nut 53 of the plug forcing the plug into the compres-. sion chamber and the flange 45 firmly against the gasket 42. The cradle 48 is pivotally supported through arms 54 and 55 to a yoke comprising yoke members 56 and 57, the arms 54 and 55 carrying pivots 58 and 59 journaled in the yoke members. The yoke members 56 and '5'! are in turn journaled at their lower ends on screws 61 and 62 in opposite sides of the body 15, and are held together at their upper ends. by means of a pin 63. The pin 63 also has journaled thereon a latch member 64, the latch member having ears 65 for the reception of the pin .63. 'A coiled spring 66 is wound about the pin 63 between the yoke members 56 and 57 and also between the ears of the latch, and acts between the yoke members and the latch to urge the same in a counter-clockwise direction facing Fig. 5. A shaft 6'7 is journaled in the yoke members 56 and 57 and supports a spur gear 68 fixedly secured on the shaft between the two yoke members and in a position to be engaged by the latch member 64. A hand wheel 69 is mounted on the outer end of the shaft 67 to permit manual rotation of the shaft and the spur gear 68. The spur gear 68 is arranged to cooperate with gear teeth '71 on the top of the body portion 19 so that upon rotation of the hand wheel 69 the yoke will be rotated about the screws 61 and 62.

Thus, to position the spark plug 44 in a testing position with respect to the compression chamber, the yoke is rotated in a clockwise direction facing Fig. 5 until it is possible to insert the plug 44 with the fingers into the compression chamber. This will ordinarily necessitate complete disengagement of the spur gear 68 and the teeth '71. When the plug is thus positioned, the yoke is rotated in a counter-clockwise direction and the cradle 48 is guided against the nut 53 of the plug. This operation may be carried out by simply grasping the yoke members and swinging the yoke. During this movement the spur gear 68 will ride onto the teeth '71. In order to finally tighten theplug into its socket, the operator grasps the hand wheel 69 and rotates it, bringing the flange 45 of the plug snugly against the gasket 42. As the hand wheel is rotated, the latch 64 clicks along the spur gear so that when the hand wheel is released the latch prevents backward movement of the gear, thus holding the plug firmly in the tightened position. To release the plug, the latch 64 is moved in a clockwise direction facing Fig. 5, thus releasing the spur gear in which position the yoke may be rotated to the aforementioned position in which the plug may be removed. The yoke is thus rotatable from an inoperative position in which the plug may be inserted into the compression chamber, and an operative position in which the plug is firmly held in its testing position within the chamber.

The piston 72 is positioned in the cylinder 22 for reciprocation to compress the air in the compression chamber. A leather or other cup 73 is positioned at the front end of the piston and is secured thereto by means of a nut '74 threaded to a rod 75 on the front end of the piston. The nut 74 is of suflicient width to completely fill the space between the flangesides of the cup and extend slightly beyond these ends so that when the piston reaches the forward end of its stroke, substantially all of the air in the cylinder is displaced. A spring ring '76 acts against the flange sides of the cup to maintain them in close proximity to the walls of the cylinder.

Referring now more particularly to Figs. 9 and 10, the piston is arranged to be reciprocated in the cylinder by means of handles 77 and 78. These handles are pivotally supported intermediate their ends on the arm 18 by means of bolts 79 and 81. The handles extend slightly beyond the pivotal points and terminate in intermeshing gear teeth 82 and 83. Through this arrangement reciprocation of one of the handles brings about a corresponding movement of the other handle which insures uniform action on the piston. The handles are slotted intermediate their ends, as shown at 84 and 85 for the reception of links 86 and 87 whichv are pivotally secured to the handles by means of pins 88 and 89 extending across the slots. The forward ends of'the links 86 and 87 are pivotally supported in a slot 91 in the rear end of the piston 72 by means of a threaded pin 92. The links are curved, as shown at 93, so as to pass into the cylinder to move the piston till the front extremity of the cylinder.

Thus, upon movement of the handles '7 and '78 toward and. away from each other, the piston '72 is r'eciprocated in the cylinder 22, drawing air into the cylinder through an opening 94 in the cylinder wall and forcing the air into the compression chamber 21 through the passageway 23, A valve is positioned in the passageway 23 and is arranged. to be opened when pressure is applied to the end adjacent to the cylind r 22 to permit the passage of air from the cylinder into the compression chamber and to be closed when this pressure is relieved to prevent the return flow of air. This valve may advantageously be of the type usually employed in automobile tires and commonly called a Schrader valve.

Electrical energy for causing a spark to pass across the spark gap of the plug during the testing operations is provided by a secondary vibratory type induct-ion coil and dry cell batteries positioned in the housing 11. The induction coil, indicated generally by the numeral 95, is connected to the center conductor 96 of the plug through a lead 97 having a spring-operated clip 98 for convenient attachment to the plug. The coil is provided with conventional vibratory mechanism 99 and is provided with electrical energy from batteries 101, 102, 103 and 104, the flow of :1

occupy their normal position shown in dotted lines in Fig. 9. Novel means are employed for holding the batteries and for making the proper battery connections. The coil 95 and batteries are supported upon a bottom panel 106 secured to the housing 11 by means of screws 107. Positioned upon the bottom panel 186 are spaced parallel vertical panels 108, 109 and 111, the vertical panels being spaced a distance slightly greater than the diameter of the batteries. A longitudinal panel 112 extends between the vertical panels and provides a series of four chambers for reception of the batteries. A top panel 113 is affixed to the top end of the panels 108-112, the distance between the top panel 113 and the bottom panel 106 being just sufiicient for the reception of the battery inclusive of the upstanding central ter-.

minal 114 thereof. Grooves 115 and 116 in bottom panel serve to receive the upstanding terminals of the batteries 102 and 193 so these batteries may only be inserted into their respective chambers with the central terminal downward. Likewise the upper plate 113 is provided with grooves 117 for the reception of the central terminals of the batteries 101 and 184 so that these may only be inserted with the terminals on the upper end. This device insures that the batteries will always be inserted in the proper manner and prevents them from at any time being accidentally improperly connected. A spring contact member 118 serves to connect the central terminal of the battery 194- with the bottom or outer terminal of the battery 192, while the contact member 119 connects the outer terminal of the battery 103 to the switch 105. Likewise the contact member 121 connects the central terminal of the battery 101jto the primary of the coil 95. Likewise spring contact members 122 and 123 on the bottcm panel 106 serve to connect opposite terminals of the batteries 101;and 102, and 103 and 104, respectively, to complete the circuit.

The switch 105 is also connected to ground bymeans of a lead 124 whereby closing of the switch tion coil 131 from this source of current.

completes the circuit through the primary of the coil, one lead of the primary of the coil being grounded by means of a lead 125. In order to facilitate the insertion and removal of the batteries from their closely confined positions, strips of cloth or similar suitable material 126'and v127 are secured to the vertical'panel 109 by means'oi screws 128 and 129 and are of sufficient length to loop into adjacent chambers, as'best shown in Fig. 2. Thus the battery is inserted with the pieces of cloth or tabs looped around them so that by pulling the ends of the tabs the batteries may be slid-cut of their operative positions.

While the means shown in Figs. 1-3, inclusive, for supplying electrical energy to the plug, under test is of advantage where it is'desired to have a completely portable testing machine, we have shown inli'igs. 11-13 a preferred electrical system, which, while lesscompletely portable than the form first above mentioned, is suiiiciently portable to normally accomplish'the purpose. In this form a secondary vibratory induction coil 131 is secured to'the bottom panel 106 by means of a strap 132, this coil having the usual vibratory elements'133. One terminal of the secondary winding of the coil is connected to the spark plug through the lead 97, the other terminal of the secondary winding being grounded. A conventional step-down transformer 134 is also secured to the bottom panel 106 within the housing 11 and is connected with the primary of the induction coil 131. The transformer 134 is connected to a conventional power receptacle 135 secured in the side of the housing 11, one of the leadsbetween the receptacle and the transformer passing through a manually controlled switch 136. Thus, when the receptacle 135 is connected to a commercial light circuit such as the'usual or 220 volt circuits, power will be supplied to the transformer when the switch 136.is closed. The

voltage of the commercial power will he stepped down in the transformer to six volts and then supplied to the induction coil 131. a It should be understood, of course, that the transformer will vary depending upon the voltage of the commercial power supply. The primary of the induction coil 131 is also connected to terminals 137 and 138 secured in the walls of the housing 11, the cir-' cuit passing through the switch 105 as previously described. The terminals 137 and 138 serve for'the connection of the conventional six volt storage battery, so that upon the closing of theswitch 105, current will be supplied to the induc- Thus, in the preferred form just described, the electrical energy may be taken fromeither a conventional storage battery or from a commercial lighting circuit, depending upon the convenience of these different sources of energy. In this manner. the cost of operating the tester will be considerably lower than when the same is operated through the use of dry cell batteries of the type shown in Figs. 1-3.

The advantage of our improved construction will doubtless have become apparent. It will be seen that the device presents a self-contained unit and does not require attachment to a supply of gas or air nor to a supply of electrical energy.

The pressurecin the compression chamberis developed by means of a pump operated through horizontally movable handles, the handles being horizontally movable in their pumping stroke.

No strain has set up through their operation and, consequently, the device may be used on the glass,

showcase of spark plug sales establishments without danger of breaking the glass during pumping operation. Furthermore, when the handlesare moved into a parallel position represented by thecompletion of the power stroke of the piston, the handles occupy a position such as to protect the switch mechanism from being accidentally actuated. The plug is inserted in the tester entirelywithout' the use of wrenches or other extraneous positioning means merely through the operation of theyoke, so that there is no danger of showcases or the porcelains of.

adjacent plugs being broken. Furthermore, the plug is inserted longitudinally into the chamber and is not screwed min the conventional manner which'materially increases the speed with which the test may be conducted, since only an instants time is required for the satisfactory insertion of the plug or the removal thereof. Furthermore, all'sizes of'plugs are tested by insertion in the same hole which renders themechanism much A novel feature of the invention is the manner 7 of supporting and retaining the batteries and the means for removing the same from their support,'the means being so constructed that the batteries cannot be inserted in an improper manner.

Attention is also directedtothe fact that we haveprovided means whereby the electrical energy for operating the tester may be obtained from either the conventional six volt storage In the former case the terminals of the battery are conbattery 'or commercial lighting circuits.

nected directly to the induction coil, whereas when the commercial lighting circuit is employed, the current is firstpassed'through a step-down transformer from which it is supplied to the induction coil at the desired voltage of six volts.

Independent switch means are provided for use withthe two circuits. 1 1

While we have thus described and illustrated a specific embodiment of our invention, we are aware that numerous alterations and changes might be made'therein without materially departing from the spirit of the invention and the scope of the appended claims, in which We claim: r

1. In a spark plug tester, a compression chamber having an open end, a compressible gasket positioned in the chamber wall'at said open end, and rack and pinion means for pressing a flange of a spark plug firmly against said gasket'when the threaded end of the plug is inserted in said chamber to provide a substantially air-tight junction between the flange'and the gasket.

2; In a spark plug tester, the combination of a compression chamber having an open end of such diameter as to permit the longitudinal insertion of the threaded end of a spark plug, a resilient gasket positioned in the walls of said chamber, means for normally maintaining the gasket in position, means adapted to bear against the nut of the plug movable toward and away from said open end for inserting and for applying longitudinal pressure to said spark plug to force the flange thereof firmly against the gasket to provide a substantially air-tight junction therebetween and a rack and pinion for moving said last mentioned means for quick insertion of plugs of variable size.

3. In a spark plug tester, the combination of a compression chamber having an open end of such diameter as to permit the longitudinal insertion of the threaded end of a spark plug, a gasket in the walls of said chamber surrounding said opening, cradle mechanism arranged to bear against the nut of the plug and a rack and pinion mechanism for actuating the cradle to press the flange thereof firmly against the gasket and provide an air-tight junction therebetween.

4. In a spark plug tester, a compression chamher having an open end on a compressible gasket positioned in the chamber wall at the open end, rack and pinion means for pressing a flange of the spark plug against said gasket when the threaded end of the plug is inserted in said chamher, and manually operable means for turning the pinion to tighten the plug in position to provide a substantially air-tight junction between the flange and the gasket.

5. The combination in a spark plug tester of a hollow base. carrying electrical supply means, a compression chamber and a pump chamber supported on the base in superimposed relationship, the compression chamber having a window defining the front thereof and an opening at the rear for the reception of a spark plug, said pump chamber also having a rear opening, a piston in the pump chamber, a pair of horizontally disposed handles positioned on either side of the pump chamber for actuation from the front toward and away from the pump chamber to actuate the piston through the rear opening of the pump chamber, a yoke pivoted on the pump chamber spanning the compression chamber for securing the spark plug in the opening thereof, and rack and pinion mechanism between the yoke and the top of the compression chamber for tightening and releasing the plug.

6. The combination in a spark plug tester of a hollow base carrying electrical supply means, a compression chamber and a pump chamber supported on the base in superimposed relationship, the compression chamber having a window defining the front thereof and an opening at the rear for the reception of a spark plug, said pump chamber also having a rear opening, a piston in the pump chamber, a pair of horizontally disposed handles positioned on either side of the pump chamber for actuation from the front toward and away from the pump chamber to actuate the piston through the rear opening of the pump chamber, a yoke having a pair of arms pivoted on the pump chamber, the yoke spanning the compression chamber, a cradle connecting the arms and pivotally supported thereon adapted to contact the nut of a plug to tighten and release the plug in the opening of the compression chamber upon pivotal movement of the yoke, a rack above the compression chamber, and a manually rotatable pinion on the yoke cooperable with the rack for the purpose of tightening the plug in the compression chamber and releasing the plug while under pressure. WILLIAM BORCHERT. FRED L. BORCHERT.

Images