DE102009038377A1 - hydraulic arrangement - Google Patents

Abstract

The invention relates to a hydraulic arrangement for controlling a plurality of clutches (10, 20) of a controllable torque distribution device
- With a high pressure circuit (100) with pressure accumulator (102) for actuating the clutches (10, 20) by switching of the individual clutches (10, 20) associated, switchable valves (110, 120) and
- With an open to an oil sump (30) low pressure pitch circle (200) for oil cooling of the clutches (10, 20), wherein the low-pressure pitch circle (200) has a switchable valve (210, 130 '), with a cooling oil flow to the clutches (10, 20) can be permitted or inhibited depending on the valve position.
The invention is characterized in that a common pressure pump (142) is connected upstream of both partial circuits (100, 200) in a common inflow and the common inflow behind a branch to the low-pressure partial circuit (200) via a non-return valve (101) blocking the pumping direction ) is connected to the high pressure circuit (100).
The invention achieves an increased degree of system integration without compromising functionality.

Description

Field of the invention

• – mit einem Hochdruck-Teilkreis mit Druckspeicher zur Betätigung der Kupplungen durch Schaltung von den einzelnen Kupplungen zugeordneten, schaltbaren Ventilen und
• – mit einem zu einem Ölsumpf hin offenen Niederdruck-Teilkreis zur Ölkühlung der Kupplungen, wobei der Niederdruck-Teilkreis ein schaltbares Ventil aufweist, mit dem ein Ölfluss zu den Kupplungen je nach Ventilstellung gestattet oder unterbunden werden kann.

The invention relates to a hydraulic arrangement for controlling a plurality of clutches of a controllable torque distribution device

• - With a high pressure circuit with pressure accumulator for actuating the clutches by switching of the individual clutches associated, switchable valves and
• - With an open to an oil sump low-pressure pitch circle for oil cooling of the clutches, the low-pressure pitch circle has a switchable valve with which an oil flow to the clutches depending on the valve position can be permitted or prevented.

State of the art

From the DE 10 2006 008 236 A1 a transmission device for motor vehicles for active torque distribution is known. The disclosed in the cited document differential is designed as axle differential. It has two clutches which can be controlled separately, the actuation of which causes a torque shift to the wheel of the axle assigned to the respective clutch.

For actuation and cooling of the couplings is not disclosed in the cited document hydraulic arrangement of in 5 The arrangement serves to control and cooling two multi-plate clutches 10 and 20 , The couplings 10 . 20 each have a Reiblamellenpaket 11 . 21 as well as a printing cylinder 12 . 22 on. The impression cylinder 12 . 22 are in the high pressure circuit 100 integrated. On the inflow side is every pressure cylinder 12 . 22 with a 3/2-way proportional valve 110 . 120 trained switching valve connected. It should be noted that in the context of the present patent application, the term of the switching valve is to be understood and includes both stepwise and infinitely variable, in particular controllable or controllable valves. The same applies to the concept of switching, which in particular also includes rules or taxes. In the illustrated state of the valves 110 . 120 are the printing cylinders 12 . 22 relieved and with the oil sump 30 connected. In their switched-on position, the valves connect 110 . 120 the pressure pistons 12 . 22 with an external pressure generating unit 40 comprising one of an electric motor 41 driven gear pump 42 oil over an oil filter 43 in the from a check valve 101 completed high pressure pitch circle 100 inflated. Behind the check valve 101 is a pressure accumulator 102 arranged in the illustrated position of the valves 110 . 120 from the pump 42 is charged, with a pressure relief valve 146 prevents the build-up of excessive overpressure. The accumulator 102 allows a very fast control of the clutches 10 . 20 regardless of the operating state of the pump 42 , For safety reasons, the impression cylinder 12 . 22 with a designed as a 3/2-way valve safety valve 130 coupled. This safety valve 130 is in the de-energized state in the illustrated position, so that the pressure cylinder 12 . 22 are always relieved in the de-energized state. To both clutches 10 . 20 to be able to control independently of one another is the high-pressure pitch circle 100 divided into two separate sub-subcircuits, the input side through the switching valves 110 . 120 and on the output side through the check valves 111 . 121 are decoupled.

Furthermore, the known arrangement comprises a low-pressure pitch circle 200 , the cooling of the disk packs 11 . 21 serves. The low-pressure pitch circle 200 is from a gear pump 44 driven and is in pumping direction against the oil sump 30 open. The pump 44 pumps oil from the oil sump 30 over a cooler 45 to a switchable valve 210 , which is designed as a 3/2-way proportional valve. With this valve, the cooling of the slats can be 11 . 21 switch as required.

Further in the 5 illustrated elements, such as pressure or temperature sensors are readily apparent to the skilled person and will not be discussed further.

adversely in the known arrangement, the low degree of system integration, which leads to high costs and comparatively high space requirements.

From the EP 1 527 938 A2 a device is known which partially couples the pitch circle for cooling the lamellae and the pitch circle for controlling the pressure cylinder. In particular, both partial circuits are assigned a common pump in a common inlet. The separation of the circles is done separately for each clutch by means of a respective switching valve, which connects the common inlet alternatively either with the pressure cylinder or the lamellar cooling. A disadvantage of this device is that a simultaneous actuation and cooling of a clutch is excluded. Another disadvantage is that the cooling takes place superfluous way with standing under high pressure oil. To build up this unnecessary pressure is wasting pump energy. In addition, the pressure reduction by cooling increases the reaction time with which the associated pressure cylinder can be pressurized.

task

It is the object of the present invention tion to increase the degree of integration of the generic arrangement, without sacrificing functionality.

Presentation of the invention

These Task is combined with the features of the preamble of Claim 1 solved by both partial circuits in one common inflow a common pressure pump is connected upstream and the common inflow past a branch to the low pressure pitch circle a counter to the pumping direction blocking check valve connected to the high pressure pitch circle.

The basic idea of the invention is as shown in EP 1 527 938 A2 basically known to supply both subcircuits via a common inflow, in contrast to the local solution, however, to maintain the separation between the high pressure and low pressure pitch circle. This is achieved by branching off the low-pressure pitch circle in front of the non-return valve closing off the high-pressure partial circuit. As a result of this separation, the common pump can be used to drive the cooling circuit as soon as the high-pressure partial circuit and the pressure accumulator connected thereto are charged. The pump can be operated optimally for low pressures and high flow rates. A pressurization of the printing cylinder can be independent and in particular carried out simultaneously with the cooling, wherein the pressure supply is carried out from the pressure accumulator.

advantageous Embodiments of the invention are the subject of the dependent Claims.

conveniently, It is envisaged that the high pressure pitch circle one of the number of Having couplings corresponding plurality of sub-pitch circles, the one in each case against the pumping direction blocking Check valve connected to a common drain are, whereby the common procedure over a switchable Safety valve is connected to the oil sump. This Feature is already known from the generic arrangement ago.

These preferred embodiment is the basis of an advantageous Further development of the invention, the further system integration serves. This development is characterized by the fact that the switchable Valve of the low pressure pitch circle and the safety valve of the high pressure pitch circle as a common combination valve with two switchable valve channels is formed, wherein a valve channel as a safety drainage channel the high-pressure circuit and the other valve channel as a switching channel the low pressure circuit acts. In this way, a valve can be saved become. The resulting combination valve is only slightly more complex than the valves originally used and needed significantly less space than the two single valves that it replaces. In particular, it may be formed as a 4/3-way valve. To the to meet the required safety requirements, the safety drainage channel is preferably designed as a normally open valve channel.

Prefers have the sub-circuits of the high-pressure pitch circle a common Inlet on, the non-return valve, which is the high pressure pitch circle separated from the low-pressure pitch, is connected downstream. The feed is with the valves connected in parallel to each other, respectively associated with the couplings connected. Conveniently the accumulator connected to this common inlet. To this Way, the control of all pressure cylinder from a common pressure accumulator be fed.

Further is preferably provided that the common inlet of the sub-sub-circuits over a spring-biased pressure relief valve with the oil sump connected is. Such a pressure relief valve serves for safety and prevents excessive overpressure in the high pressure pitch circle. If such a fuse in the common inflow of sub-districts Arranged on an individual hedge of each individual Sub-district are waived.

When Pump has a driven by an electric motor gear pump proven. However, it is also possible as a gear pump a torque transmitting gear transmission stage with the expert common modification by sickle and side plates too use. Basically, any other type of pump is suitable.

Further it is preferably provided that at least two of the sub-pitch circles of the high-pressure pitch circle by a connecting valve and a pressure relief valve connected to the oil sump are. Such a valve combination allows the To monitor the actuation pressures of the individual clutches and to limit to a maximum pressure.

preferred wise, at least two individual pressures of the subcircles will be Additively linked by the logic valve. This valve logic of an "and" valve has the Advantage that not only the maximum pressure of the individual coupling is monitored, but that it is possible through the link also the maximum pressure of the two clutches in the operating state to monitor together. This will be circular performance avoided within the transmission from a certain height and thus a transmission protection function against component overload realized.

Around the requirements regarding the required installation space and to take account of the reduction of costs, the pressure relief valve integrated into the connecting valve. This creates a functional Unit that meets the requirements described By avoiding duplicate components, saving costs and installation space become.

A advantageous embodiment of a connecting valve is designed such that it has a stepped piston, which with is provided corresponding control edges. Such a valve offers the possibility of the pressure of the hydraulic medium directly through derive the movement of the control piston, since the control edges corresponding Release holes in the valve as soon as the pressure is proportional the control piston is covered. The advantage of this Valve design lies in the small number of moving components, which contributes to cost reduction.

A further advantageous embodiment of a connecting valve is a ball seat valve. In this case, an actuating piston acts with one, pressed by a coil spring against a ball seat Ball together. In this version, there is the possibility the control pressure spatially from the working pressure of the clutches to separate. This may be advantageous in the case that in the integration of the connecting valve space engineering Particularities to be considered are those such Make connection seem reasonable. A ball seat valve has has more components than a valve of the type described above but the advantage that the piston less prone to Component tolerances is because the piston is not simultaneously control member with respect to the flow.

Which Embodiment of the valve for the respective Application is useful, is the knowledge of the expert in let the selection, because a variety of boundary parameters influence here.

Further Features and advantages of the invention will become apparent from the following, special description as well as the drawings.

Brief description of the drawings

It demonstrate

1 a hydraulic system according to the invention;

2 a further embodiment of a hydraulic arrangement according to the invention

3 : Hydraulic valve

4 : Hydraulic valve

5 a hydraulic arrangement according to the prior art

Detailed description more preferred embodiments

1 shows a schematic representation of a hydraulic system according to the invention. In the 1 Reference numerals used correspond to those in FIG 5 , which has been described above, used reference numerals. For an explanation, see the description of 5 directed. Below are essentially only the differences between the inventive arrangement according to 1 and the known arrangement according to 5 to be discussed.

The arrangement of 1 differs in three important ways from that of the 5 , First, the pressure generating unit for the high-pressure pitch circle 100 integrated into the overall structure of the transmission. Second, the independent pumps 42 and 44 for the different subcircles 100 and 200 in a common, two circuits upstream pump 142 combined. The third was the safety valve 130 of the high pressure pitch circle and the switching valve 210 of the low-pressure pitch circle 200 to the switchable combination valve 130 ' combined. These measures increase the degree of system integration of the arrangement according to the 1 significantly compared to the arrangement according to 5 ,

The above measures have been implemented as follows. The constituencies 100 and 200 remain functionally separate. They only have a common point immediately behind the common gear pump 142 on. In this area there is a common inflow of subcircles 100 . 200 , The branch of the low-pressure pitch circle 200 downstream is a counter to the pumping direction blocking check valve 101 ,

This Valve ensures that in both subcircles different Pressure levels can be maintained.

Another point of contact of the two subcircles 100 . 200 in the new combination valve 130 ' is only apparent nature. Actually, the combination valve has 130 ' two functionally separate valve channels, so that a substantially independent circuit of the two sub-circuits 100 . 200 is possible without a functional connection of the subcircuits 100 . 200 would be generated thereby.

The operation of the arrangement according to 1 . that of a central control unit 300 is controlled, can be described as follows. In the illustrated position of the valves 110 . 120 and 130 ' is the inflow to the low-pressure partial circles 200 through the valve 130 ' locked, so that by the electric motor 141 driven gear pump 142 Oil from the oil sump 30 over the oil filter 143 and the check valve 101 promotes into the high-pressure pitch circle. Because the valves 110 . 120 Lock in the position shown, the pressure accumulator 102 charged. The build-up of too high overpressure is caused by the pressure relief valve 146 , which is designed as a spring-biased check valve, reliably prevented. The pressure pistons 12 . 22 are in the position shown above the valves 110 . 120 with the oil sump 30 connected and thus relieved. An oil cooling of the Lamallenpakete 11 . 21 over the low-pressure pitch circle 200 does not take place in the position shown. An actuation of the clutches 10 . 20 by pressurizing the impression cylinder 12 . 22 is also not possible in the position shown, since when switching through one or both valves 110 . 120 the pressure over the check valves 111 respectively. 121 and the through-connected safety valve 130 ' in the oil sump 30 would be derived.

An actuation of the clutches 10 . 20 is only in the middle and right position of the combination valve 130 ' possible. In particular, the middle position allows actuation of the clutches 10 . 20 without cooling the plate packs 11 . 21 , Will in this middle position of the combination valve 130 ' for example, the first switching valve 110 , which is the first clutch 10 is assigned, switched, can from the pressure accumulator 102 and / or the gear pump 142 supplied pressure to the printing cylinder 12 the clutch 10 be supplied. In this state, the check valve 111 open; the check valve 121 locks but and thus separates the two sub-subcircuits of the high-pressure pitch circle 100 , The conditions upon actuation of the second switching valve 120 , which is the second clutch 20 is assigned are analog. Because the combination valve 130 ' in its middle position also the second, the low-pressure pitch circle 200 assigned valve channel locks, takes place in this position, no cooling of the disk packs 11 . 21 ,

This is only in the right position of the combination valve 130 ' possible. Regarding the conditions when operating one of the switching valves 110 . 120 of the high pressure pitch circle 100 can be referred to the previously said. In contrast, however, is the low pressure valve port of the combination valve 130 ' open in this position. This allows the gear pump 142 Oil from the oil sump 30 directly into through the check valve 101 from the high pressure pitch circle 100 separate low pressure pitch circle 200 feed and to the plate packs 11 . 21 conduct. These are flowed through with promoted oil, which then depressurized the oil sump 30 is supplied.

The promotion of the cooling oil takes place in this state directly via the gear pump 142 , This is due to the pressure accumulator 102 maintained high pressure in the high pressure pitch circle 100 through the check valve 101 completely decoupled from this. This means that the gear pump can operate in this state in an operating point, which can be operated on the low-pressure promotion of large volumes of liquid, ie in particular at high speeds. During this time required operations of the clutches 10 . 20 can be fed out of the pressure accumulator responsively, ie with very short switching times. Only when the pressure in the accumulator 102 stored pressure drops below a predetermined level, the cooling must be switched by switching the combination valve 130 ' interrupted and recharged the accumulator in the manner described above.

As mentioned, the control of the arrangement takes place via the central control unit 300 , the state parameters of the system of suitably arranged pressure sensors (in 1 indicated) and temperature sensors (in 1 not shown), e.g. B. gets delivered via a data line or bus system.

A further advantageous embodiment shows 2 , Here is in extension of in 1 described hydraulic arrangement in the high-pressure pitch circle 100 a connection of the two supply lines to the pressure cylinders 12 . 22 the two clutches 10 . 20 been created. The two lines become a connecting valve 140 guided. This connection valve 140 is designed as a so-called "and" valve. This means that the partial pressures of the two supply lines are added functionally. In functional unit with this connection valve 140 becomes a pressure relief valve 131 used, which at a preset pressure value, a connection of the clutch pressure lines to the oil sump 30 opens. This embodiment enables a maximum pressure monitoring in the supply lines to the two pressure cylinders 12 . 22 ,

The additive operation of the connection valve 140 and the pressure relief valve 131 allow the pressure monitoring in the way that both the exceeding of a predetermined maximum pressure in a supply line, as well as exceeding the maximum pressure as the sum of the two partial pressures to open the pressure relief valve 131 and thus to a pressure reduction in the oil sump 30 leads.

This intelligent form of maximum pressure monitoring allows the pressures in Be drive located couplings 10 . 20 to limit here to prevent increased circular power in the transmission and thus reduce the mechanical stress on the individual transmission components.

Due to the control-technical flexibility, which offers this hydraulic arrangement, it is still possible, the clutches 10 . 20 , To reduce drag losses, to equip with a large air clearance and still a quick response of the clutches 10 . 20 to ensure. These are the clutches 10 . 20 before an impending actuation, which is caused by sensors not described here in the vehicle, until briefly driven by the point of the first torque transmission, called "Kisspoint". This can optionally be done with maximum pressure which significantly reduces the reaction time of the entire system, since the couplings can be filled with maximum volume flow without having to accept the risk of pressure peaks.

The 3 and 4 show embodiments, such as the connecting valve 140 as a unit with the pressure relief valve 131 can be designed.

The 3 shows such a valve in the embodiment as a piston valve 60 with a stepped piston 61 , This stepped piston 61 is in a valve housing 62 movably mounted and is on one side over a spiral spring 63 acted upon with a force. For guiding the spiral spring 63 is the stepped piston 61 with a cylindrical approach 64 provided that the spiral spring 63 leads and tilts inside the case 62 prevented. The housing 62 is with several holes 65 . 66 . 67 68 Mistake. The hole is used 65 to connect the part of the high-pressure pitch circle 100 to the clutch 10 leads. The part of the high pressure partial circle 100 the clutch 20 supplied with hydraulic fluid, is at the bore 67 connected. About the holes 66 . 68 takes place in the actuation case of the valve, the discharge of the hydraulic medium from the corresponding pitch circles in the oil sump 30 ,

To represent the desired function is the stepped piston 61 with a first piston surface 69 and a first control edge 71 and a second piston surface 70 and a second control edge 72 Mistake. Be one or both piston surfaces 69 and or 70 pressurized with hydraulic medium, the stepped piston 61 against the force of the coil spring 63 postponed. Is a corresponding displacement of the stepped piston 61 achieved, so are from the control edges 71 and 72 the corresponding holes 66 and 68 opened and the pressure medium can into the oil sump 30 flow away.

4 shows a further conceivable embodiment of a connecting valve 140 , In this embodiment, the valve is a ball seat valve 80 executed. This valve has a ball 81 on, by a coil spring 63 against a valve seat 82 is pressed. This spring force directed counteracts a piston 83 the with a first piston surface 84 and a second piston surface 85 is provided. The piston 83 , the ball 81 and the coil spring 63 are analogous to 3 also in a valve housing 92 stored. Also the valve housing 92 is with several holes 86 . 87 . 88 . 89 . 90 . 91 Mistake. The holes form 86 . 88 the connections of the supply lines of the couplings 10 . 20 , The holes 87 . 89 only serve to relieve the piston chambers. Both supply lines of the couplings 10 . 20 are still with the hole 90 connected. About this hole 90 is the monitored system pressure of the high pressure pitch circle with the ball seat valve 80 connected.

The operation of the ball seat valve 80 is analogous to the piston valve 60 , By applying the piston surfaces 84 and 85 with hydraulic pressure is the piston 83 postponed. This presses against the ball 81 and lifts them against the force of the coil spring 63 from her ball seat 82 off, so that the system pressure from connection hole 90 between ball 81 and ball seat 82 can escape and over the hole 91 in the oil sump 30 is dissipated.

Of course, those discussed in the special description and in the 1 and 2 The arrangement shown only two advantageous embodiment of the present invention. The expert is given in the light of the present disclosure, a wide range of possible variations based. In particular, the number of clutches can be adapted to the requirements of the case. Also, the special design of the valves, here as 3/2-way valves for the switching valves 110 . 120 and as a 4/3-way valve for the combination valve 130 ' are favorable but not mandatory for the invention and can be modified accordingly by the expert in the individual case. Finally, the special design of the pump 142 at the discretion of a person skilled in the art, although an electric motor-driven gear pump is particularly advantageous.

10

clutch

11

Disc pack of 10

12

Printing cylinder of 10

20

clutch

21

Disc pack of 20

22

Printing cylinder of 20

30

oil sump

40

external Pressure generating unit

41

electric motor

42

pump

43

oil filter

44

pump

45

oil cooler

60

piston valve

61

stepped piston

62

valve housing

63

spiral spring

64

approach

65

drilling

66

drilling

67

drilling

68

drilling

69

first piston area

70

second piston area

71

first control edge

72

second control edge

80

Ball seat valve

81

Bullet

82

valve seat

83

piston

84

first piston area

85

second piston area

86

drilling

87

drilling

88

drilling

89

drilling

90

drilling

91

drilling

92

valve housing

100

High-pressure circuit

101

Input check valve

102

accumulator

110

first switching valve of 100

111

first check valve

120

second switching valve of 100

121

second check valve

130

safety valve

130 '

combination valve

131

Pressure relief valve

140

linking valve

141

electric motor

142

gear pump

143

oil filter

146

Pressure relief valve

200

Low-pressure circuit

210

Switching valve of 200

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102006008236 A1 [0002]
• - EP 1527938 A2 [0007, 0010]

Claims (13)

Hydraulic arrangement for controlling a plurality of clutches ( 10 . 20 ) a controllable torque distribution device - with a high-pressure pitch circle ( 100 ) with accumulator ( 102 ) for actuating the clutches ( 10 . 20 ) by switching from the individual clutches ( 10 . 20 ), switchable valves ( 110 . 120 ) and - with a to an oil sump ( 30 ) open low pressure pitch circle ( 200 ) for oil cooling of the clutches ( 10 . 20 ), wherein the low-pressure pitch circle ( 200 ) a switchable valve ( 210 ; 130 ' ), with which a cooling oil flow to the couplings ( 10 . 20 ) can be permitted or inhibited depending on the valve position, characterized in that both partial circuits ( 100 . 200 ) in a common inflow a common pressure pump ( 142 ) and the common inflow behind a branch to the low-pressure pitch circle ( 200 ) via a counter to the pumping direction blocking check valve ( 101 ) with the high pressure pitch circle ( 100 ) connected is. Hydraulic arrangement according to claim 1, characterized in that the high-pressure pitch circle ( 100 ) one of the number of couplings ( 10 . 20 ) has a corresponding plurality of sub-sub-circuits, which in each case via a non-return valve blocking the pumping direction ( 111 . 121 ) are connected to a common drain, wherein the common drain via a switchable safety valve ( 130 ; 130 ' ) is connected to the oil sump. Hydraulic arrangement according to claim 2, characterized in that the switchable valve of the low pressure pitch circle and the safety valve of the high pressure pitch circle as a common combination valve ( 130 ' ) is formed with two switchable valve channels, wherein a valve channel as a safety drain channel of the high pressure circuit ( 100 ) and the other valve channel as the switching channel of the low-pressure circuit ( 200 ) acts. Hydraulic arrangement according to Claim 3, characterized that the safety drainage channel as a normally open valve channel is trained. Hydraulic arrangement according to one of claims 2 to 4, characterized in that the sub-sub-circuits of the high-pressure pitch circle ( 100 ) a check valve separating the pitch circles ( 101 ) downstream, common inlet connected to the couplings ( 10 . 20 ) associated, parallel to each other valves ( 110 . 120 ) connected is. Hydraulic arrangement according to claim 5, characterized in that the pressure accumulator ( 102 ) is connected to the common inflow of the sub-constituencies. Hydraulic arrangement according to one of claims 5 to 6, characterized in that the common inlet of the sub-sub-circuits via a spring-loaded pressure relief valve ( 146 ) is connected to the oil sump. Hydraulic arrangement according to one of the preceding claims, characterized in that the pump as by an electric motor ( 41 ; 141 ) driven gear pump ( 42 ; 142 ) is trained. Hydraulic arrangement according to one of the preceding claims, characterized in that at least two of the sub-sub-circuits of the high-pressure partial circuit ( 100 ) by a connecting valve ( 140 ) and a pressure relief valve ( 131 ) with the oil sump ( 30 ) are connected. Hydraulic arrangement according to claim 9, characterized in that at least two individual pressures of the sub-sub-circuits through the connecting valve ( 140 ) are additively linked. Hydraulic arrangement according to claim 9 or 10, characterized in that the pressure relief valve ( 131 ) in the connecting valve ( 140 ) is integrated. Hydraulic arrangement according to claim 9, characterized in that the connecting valve ( 140 ) a stepped piston ( 61 ), the control edges ( 71 . 72 ). Hydraulic arrangement according to claim 10, characterized in that the connecting valve ( 140 ) an actuating piston ( 83 ) in operative connection with one, by a coil spring ( 63 ) charged ball ( 81 ) stands.