Abstract: A pneumatic drive unit is provided for partially opening a vehicle body part such as a trunk lid. The pneumatic drive unit includes a working chamber which in use applies pressure to move a control member which engages a contact surface of the vehicle body part. A vent channel is provided which selectively connects the working chamber with the atmosphere as a function of the position of a movable closing element of the drive unit element and contact of the control member with the vehicle body part such that when the body part is closed after a partial opening, the drive unit is ready for another control operation.

Abstract: A fluid-operated brake actuator having a housing with one or more vent openings in communication with an interior chamber is provided with a filter assembly mounted to the housing over the vent openings.

Abstract: An actuator including a jack having first and second pistons engaging a control rod, particularly for rotating the shaft of a fraction-of-a-turn plumbing device. The actuator can also include energy storage cartridges and/or damping members placed between the pistons. The energy storage cartridges can engage the first piston on one side and the second piston on the opposite side.

Abstract: An electro-hydraulic valve actuator comprising an actuator casing; a piston/rack means in the casing having walls reciprocating linearly to effect linear movements, the reciprocating walls defining a center chamber therebetween and two outside chambers inside the casing; an output shaft in communication with the piston/rack means for driving a valve, the output shaft effecting rotational movements in response to the linear movements of the piston/rack means; resilient return means in each of the two outside chambers engaging the reciprocating walls of the piston/rack means and inner end walls of the casing, the resilient return means biasing the reciprocating walls of the piston/rack means to a closed position; a pumping means; a primary internal flow path for transferring hydraulic fluid from the pumping means to a first output port and into the center chamber, the hydraulic fluid in the center chamber causing the piston/rack means to expand in the casing to transmit the linear movements to the output shaft;

Abstract: A brake actuator for use on passenger transit railway vehicles, is disclosed. The actuator includes a housing containing a service piston and a parking brake piston. The service piston is connected to an inner hollow stem having a forward conical surface disposed to engage a conical surface of a collet provided on a threaded rod located within the stem. The parking brake piston has a hollow outer sleeve surrounding the hollow stem, while a coil spring is located about the outer sleeve for applying a braking force when fluid pressure is removed from a housing containing the parking brake piston. The spring expands against a locking ring located on a forward sleeve secured to an intermediate sleeve that engages the hollow stem. This causes forward movement of the outer sleeve and forward movement of the conical portion of the hollow stem into engagement with the conical portion of the conical surface of the collet. This, in turn, moves the threaded rod to engage brake applying components of a transit vehicle.

Abstract: A toggle valve includes a valve stem which moves a valve body towards and away from a valve seat, an operation member separate from the valve stem, valve stem rollers which are supported by the valve stem and which have shafts whose axes extend in a direction perpendicular to the direction of the sliding movement of the valve stem without intersecting the same, a tapered surface provided on the end of the operation member adjacent to the valve stem, and intermediate rollers which are provided between the tapered surface of the operation member and the valve stem rollers to come into contact with the tapered surface and the valve stem rollers.

Abstract: An apparatus for maintaining hydraulic pressure in a spring applied hydraulicly released brake actuator and activating a parking brake light upon stroking the actuator to apply the parking brake in the system, the apparatus including a housing, a compression spring axially aligned in the housing, a cap mounted on one end of the housing, a cylinder formed in the cap, a piston mounted in the cylinder, a spring cup operatively connecting the piston to the compression spring, the piston rod being operatively connected to the piston and to the brake, a tubular housing having a magnetic switch at each end axially aligned with the piston rod, and a cylindrical tube having a magnet mounted thereon aligned with the tubular housing for actuating one or the other of the magnetic switches, one of the switches being actuated on a drop of pressure in the system and the other switch being operatively connected to a parking brake light to signal a loss of pressure in the system and actuation of the parking brake.

Abstract: An air-operated diaphragm spring brake actuator has a pressure plate formed entirely of plastic. The diaphragm is secured to the pressure plate by ultrasonic welding. The pressure plate also has a central hub which centers the opening and receives the actuator rod in press-fit engagement.

Abstract: A brake actuator (10) for a vehicle comprises a service brake housing (14), a tandem spring brake housing (16) and a diaphragm (52), dividing the interior thereof into a first spring chamber (62) and a second spring chamber (63). In one embodiment, the first spring chamber (62) is completely sealed from the environment, being open only through a hollow actuator rod (56) connected to the diaphragm (52) and extending from the first spring brake chamber (62) into the service brake housing (14). A control valve (300) in the actuator rod (56) controls flow through the actuator rod (56) and is closed when the actuator rod (56) is retracted and also when the actuator rod (56) is extended to apply the brakes. The control valve (300) is open only as the diaphragm (52) and actuator rod (56) are moving.

Abstract: The fluid-operated brake actuating mechanism comprises a casing having a partition wall to divide the casing into upper and lower coaxial chambers. First and second fluid-tight diaphragms are mounted in the upper and lower chambers, respectively. First and second ports enable injection of a pressurized fluid in the cavities delimited in the upper chamber between the first diaphragm and the partition wall and in the lower chamber between the second diaphragm and the partition wall. A coaxial power spring is mounted into an enclosure formed in the upper chamber at the upper end of the casing for limiting axial extension of the power spring upon opening of the casing to access the upper chamber. The upper chamber can therefore be accessed easily and safely upon maintenance of the brake actuating mechanism.

Abstract: A hydraulic system for accommodating fluid pressure variations is provided. The system includes a housing for an actuating piston with the housing having a first end with a hydraulic fluid port and a second end. The actuating piston includes a body portion, having a face, and a rod portion. A first resilient member is confined between the actuating piston and the second end of the housing. A second resilient member is confined between the body portion and the face of the actuating piston. The face of the actuating piston is preferably a pressure accommodating piston which moves relative to the body portion of the actuating piston. Preferably, the second resilient member has a tension force greater than the tension force of the first resilient member. As the actuating piston moves against the bias of the first resilient member toward the second end of the housing in response to hydraulic fluid entering the housing through the fluid port, the movement of the actuating piston is limited by a stop.

Abstract: A small envelope is achieved for an inelastically deformed connection between a spring cover and a central housing in a spring brake actuator. The connection is deformed radially inwardly and then extends radially outwardly from the radially inwardly extending portion. This eliminates the radially outwardly extending portion and flanges as are typically utilized in the prior art. Thus, a much smaller envelope is provided. In preferred embodiments of this invention, a seal groove is positioned axially adjacent a securement groove in the central housing. A seal is positioned in the seal groove to ensure an air-tight seal. In addition, a unique diaphragm guiding structure is incorporated into one embodiment of this invention.

Abstract: A spring break actuator (10) with a cast aluminum adapter (74) partially defining tandem spring brake and service brake portions has several corrosion fuses on the adapter. Each corrosion fuse is defined by a recessed or thinned area which does not compromise the structural integrity of the adapter.

Abstract: A bearing (104) is mounted to the caging bolt head (86) within a hollow actuator rod (60) of a spring brake actuator (14). The bearing (104) is self-lubricated to guide movement of the actuator rod during application and release of the spring brake and to minimize friction.

Abstract: A spring brake actuator includes a unique release bolt having two distinct threaded portions. A first-threaded portion is received in a threaded insert in the brake actuator outer housing. The second-threaded portion has its threads extending in an opposed direction to the first-threaded portion and is threadably received within a nut caging member. The nut is received in a bore in the push rod and constrained against rotation relative to the push rod. The nut moves axially within the push rod. The second-threaded portion rotates with the entire release bolt. When the release bolt is rotated, the first-threaded portion moves outwardly of the threaded insert, and the nut moves with the release bolt. At the same time, the second-threaded portion is rotating within the nut, and the nut moves axially relative to the second-threaded portion. The nut is moving axially due to two actions of the release bolt.

Abstract: An improved spring brake actuator includes a dome extending into the service chamber from the center housing. The spring chamber push rod is formed with a plate having a cross-section corresponding to the dome. The service chamber diaphragm as well as the service chamber piston are also formed with surfaces that correspond to the shape of the dome. The surfaces "stack up" to ensure alignment between the spring chamber push rod and the service chamber push rod. The use of the dome also provides additional stroke to the spring chamber push rod without requiring additional axial length for the overall brake actuator.

Abstract: A device for securing a cylinder liner (3) to a respective pumping module (2) in a reciprocating pump has a set of arrangements each with a hydraulically activated piston (8), a rod (11) of which is adapted to receive a nut (12), the retraction of which forcibly compels in attraction the cylinder liner (3) and the pumping module (2).

Abstract: A vacuum motor 10 for an automotive vehicle comprises a generally cylindrical housing 12 having an end wall 14 with the depression 16 therein and a diaphragm 22 axially reciprocating within the housing. The diaphragm includes an annular ridge 38 having a predetermined diameter which provides an interference fit for a spring 40 contained within the housing. The interference fit of the spring within the housing reduces the vibration of the spring and the objectionable noise produced by the vacuum motor.

Abstract: A controller comprises a valve body having a valve element and a valve seat defining a fluid cannel openable and closable with a reciprocating upward and downward movement of a valve stem, a casing fixed to an upper portion of the valve body, an operating rod provided in an upper inside portion of the casing upwardly and downwardly movably, a drive device for moving the rod upward and downward, and a transmission device provided in a lower inside portion of the casing for transmitting a force acting on the rod to the valve stem.

Abstract: A diaphragm for spring brake actuators includes an aperture that receives a threaded securement member such that the diaphragm is directly fixed to a push rod. In this way, misalignment between the push rod and the diaphragm is eliminated. To overcome any leakage through the aperture the diaphragm is formed with sealing beads compressed by the securement member to achieve a seal. Preferably, diaphragm plates are received on each side of the diaphragm, and the sealing beads are compressed by the securement member to achieve a seal between the securement member and the diaphragm plates. An adequate seal is thus achieved, while still allowing the direct connection of the diaphragm to the push rod by a threaded connecting member. The diaphragm plate on the power spring side of the diaphragm extends upwardly into a recess in the power spring plate, and is in facial contact in an axial direction with a surface of the power spring plate when the spring is actuated.

Abstract: A pneumatic actuator including a first housing having a first cylinder formed therein, a first piston slidably positioned within the cylinder of the first housing, a first rack connected to the first piston and extending therefrom, a second housing having a second cylinder formed therein, a second piston slidably positioned within the second cylinder of the second housing, a second rack connected to the second piston and extending therefrom, and a pinion engaging the first and second rack and rotatable relative to a movement of the first and second racks. The first piston has a center axis aligned with a point of contact between the first rack and the pinion. The second piston has a center axis aligned with a point of contact between the second rack and the pinion. Each rack is supported against the pinion by a pin supported by support members arranged transverse to the axis of the pinion.

Abstract: The present invention relates to a cylinder-operated driving mechanism for a ball valve, and more particularly to a cylinder-operated driving mechanism for a ball valve in which a plurality of guided compression springs are loaded between the cylinder caps at two ends of the cylinder and the two horizontally opposite pistons of the cylinder such that when there is no air supplied to the cylinder for driving the closing of the ball valve, the compressed spring force stored in the guided compression springs can push the two pistons to move toward each other and thereby turn the driving shaft connected to the pistons via links and driving shaft seat and further stably and reliably drives the ball valve to turn close.

Abstract: A connection apparatus for connection with an inside of a fluid conduit including seal member, sleeve member and collet assembly to seal and grip the fluid conduit which is in fluid communication with a fluid passageway. The connection apparatus further includes a resilient member and a control valve to cause actuating and deactuating relative movement between the collet assembly and the sleeve member so as to grip and seal the inside of the fluid conduit.

Abstract: A dust guard is provided for a brake actuating mechanism comprising a housing having first and second end walls, an elastomeric diaphragm suspended within the housing, a brake actuating rod disposed within the housing for reciprocating movement relative to the housing and having a first end and a second end, the second end being directed towards the second end wall of the housing, and a spring disposed within the second chamber between the second end wall and the diaphragm. The dust guard comprises a resilient tubular barrier, attached at one to the second end wall, and extending inwardly axially to engage the actuating rod, or structure connected to the actuating rod, to isolate the second end of the actuating rod from the interior of the housing.

Abstract: An air-operated combination diaphragm spring brake has a tamper-resistant connection between a head (46) and a spring side of a flange case (18) which together form a spring chamber (16) housing a power spring (66). The head (46) has an annular rim (70), and the flange case has an annular flange (78) with a diaphragm (48) sandwiched therebetween. A plurality of tabs (102) on one flange rotate into L-shaped channels (94) to lock the head to the flange case with a bayonet style engagement. An alternative embodiment employs threads (112, 114) on the head and adapter flanges to seal the spring chamber. A further embodiment seals the head to a cast flange case using a threaded hoop 116 fitted over the flange case to engage the threads on the head flange.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: A return spring (40,60) operable with piston means (30) for use in fluid operated friction torque transmission devices (11) including relatively rotatable members (12,13) carrying a plurality of torque plates (18,22), one of the members providing a fluid chamber (34) in which the piston means is reciprocable. Such a spring comprises flexible base means (41,61) carried within a recess (50,51) provided in the rotatable member and spring tab means (43,66) extending from the flexible base means and engageable with a wall (52) of the piston means; the tab means being movable with the piston means upon movement thereof in and out of the chamber in response to activation of the piston means.

Abstract: The camshaft tends to change in reaction to pulses which it experiences during its normal operation, and it is permitted to change only in a given direction, either to advance or retard, by selectively blocking or permitting the flow of hydraulic fluid, preferably engine oil, through the return lines (194,196) from the recesses (132a, 132b) by controlling the position of a spool (800) within a valve body (798) of a control valve (792) in response to a signal indicative of an engine operating condition from an engine control unit (808). The spool is centered during normal operation when the hydraulic loads acting on its opposed ends by the action of springs (802, 804) that also act on the opposed ends of the spool are in balance. During periods of operation when system pressure is low, a biasing mechanism forces the spool to its full advance position.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: A railway brake actuator which provides both service and parking braking comprises a cylinder having an operating cavity. A piston assembly in the operating cavity has a stepped bore forming second and third cavities and is extended by hydraulic pressure and retracted by a spring to apply and release the service brake. Hydraulic pressure extends a hollow parking brake piston from the second cavity to extend the piston assembly and apply the parking brake. A one-way clutch comprising ramps and rollers locks the piston in parking brake applied position. Hydraulic pressure disables the clutch to enable spring retraction of the parking brake piston and the piston assembly to release the parking brake. A gripper ring on the piston assembly operates between cylinder abutments to limit piston assembly retraction to provide slack, and enables slippage on the piston assembly on extension to adjust for brake wear.

Abstract: A diaphragm valve for high pressure use has a metal diaphragm which is actuated into and out of direct engagement with a valve seat by an air operator acting through a force multiplying lever assembly. The valve seat is confined by rigid interior and exterior sleeves while the sealing surface is contoured to have a concave configuration corresponding to the contour of the diaphragm in its deflected position. The air operator is provided with a stroke adjustment mechanism that is locked in adjusted position by a member that is generally accessible only when the operator is disconnected from the valve.

Abstract: A diaphragm valve for high pressure use has a metal diaphragm which is actuated into and out of direct engagement with a valve seat by an air operator acting through a force multiplying lever assembly. The valve seat is confined by rigid interior and exterior sleeves while the sealing surface is contoured to have a concave configuration corresponding to the contour of the diaphragm in its deflected position. The air operator is provided with a stroke adjustment mechanism that is locked in adjusted position by a member that is generally accessible only when the operator is disconnected from the valve.

Abstract: The invention is a valve actuator or a booster module for an existing valve actuator that provides an incremental force to the valve stem at a position close to valve closure. The force is stored in a spring which is held in the compressed position by a collet. Upon sufficient movement of the valve actuator stem in the direction towards valve closure, the collet which had previously held the spring in a compressed position is freed to move to allow the spring to expand against the collet. Since movement of the collet has caused it to be engaged to the valve actuator stem, the spring forces are transmitted directly to the valve actuator stem via the collet. The spring is oriented in a direction substantially parallel to the valve stem so that substantially all of its retained energy is transmitted directly to the valve stem through the collet.

Abstract: The invention concerns a braking device with a piston that can be acted upon by a pressure medium from a pressure medium chamber against the force of a actuation spring. The piston is connected through an actuation arm with a brake linkage. In order to reduce the dimensions of the braking device, the actuation spring and the actuation arm are parallel and coaxial to each other, such that the actuation spring and the actuation arm are located between the moment arms of the brake linkage.

Abstract: An apparatus for actuating an emergency brake on loss of fluid pressure in a brake system, the apparatus including a housing for one or more compression springs, a piston and cylinder assembly mounted in the housing and being operatively connected to the fluid system and to the emergency brake to release the brake on sensing brake system fluid pressure and to apply the brake on loss of system pressure in the brake system, the spring or springs being permanently housed in the housing in a precompressed condition so that the piston and cylinder assembly can be removed from the housing without releasing the springs.

Abstract: A hydraulically or pneumatically actuated muscle has an elongated elastomeric bladder that is covered by a tubular sheath. A fluid conduit is coupled to the bladder to supply hydraulic or pneumatic pressure. A coil tension spring is attached to a distal terminator of the muscle and extends to the distal end of a compression tube covering the bladder and braid. The evacuation spring draws the braid and bladder towards their fully extended state when fluid pressure is relieved and ellshaped retaining pin in the muscle terminator has one end that extends radially outward to lodge between turns of the evacuation spring. Split shoulder washers secure the proximal and distal ends of the compression tube.

Abstract: An emergency compressed-air brake for automobiles has the advantage to combine integrally the emergency braking, the service braking and the parking braking, which can be widely used in various road vehicles. The combined braking air-chamber involved is simple in construction. The thrust of braking includes two parts, the air pressure thrust and the spring thrust, with the resultant force of the two thrusts as a service braking thrust, with the spring thrust as a parking and emergency braking thrust. Since the spring force throughout joins in the braking, the braking gets more smoothness and is able to anti-locking.

Abstract: An air-operated diaphragm spring brake (10) is provided with a mounting means (16) which permits adjustment of the position of the pneumatic ports (30, 32) on the brake with respect to the vehicle. The mounting means (16) comprises a plate (84) mounted to an end section (88) of a housing (82) overlying a central aperture (90). A pair of threaded mounting studs (96) are fixedly secured to the plate (84) for mounting the plate to the vehicle.

Abstract: An improvement in a conventional air-operated diaphragm spring brake is provided by a guide (100) being disposed in registry with an aperture (26) in a service brake housing (16). A push-rod (10) extends from a diaphragm (58) within the housing (12) through the bushing (102) to pivotably connect to a slack adjuster (6). The bushing (102) serves to maintain the push-rod (10) at a preselected angle relative to the slack adjuster (6) when the push-rod is in the inoperative position.

Abstract: A dual function brake and manual drive actuating system for selectively holding a rotatable member of a drive train and manually driving the drive train. A support structure is provided, with a brake operatively associated between the support structure and the rotatable member for holding the member against rotation. A common release member is operatively associated with the brake. A fluid retracting mechanism operates against the common release member to selectively hold the brake in disengaged condition. A manual retracting mechanism also operates against the common release member to selectively hold the brake in disengaged condition. A manual drive is incorporated in the manual retracting mechanism for manually rotating the rotatable member when in the disengaged condtion.

Abstract: Service/emergency brake actuator mechanism for use with the air brake system of a wheeled vehicle. A plurality of breather holes or openings are provided in the housing section of the emergency brake actuator chamber that houses the emergency actuator spring to maintain the chamber at atmospheric pressure. The openings are arranged such that regardless of the orientation of the brake actuator mounted in the wheeled vehicle, one of those openings will be located in the upper hemisphere of the chamber housing and another opening will be located in the lower hemisphere of the chamber housing. A flow resistant plug member, adapted to fit into any of the openings, is provided to seal whichever opening is oriented in the upper hemisphere of the chamber housing. This arrangement minimizes the amount of dust and dirt particles that enter the chamber and, thus, keeps the chamber free of contamination that could hinder actuator performance.

Abstract: The invention provides an open breather chamber in front of the breather chamber proper with the cross-sectional and length ratios lying within certain configurations so that solids, fluid and steam particles will enter the breather chamber and not cause problems within a chamber containing working components.

Abstract: The present invention teaches a brake cylinder which is formed by a cylindrical housing and a cylinder base. The cylindrical housing and cylinder base are joined together by a bayonet connection and form a pressure chamber. The bayonet connection is designed pressure-tight, and it is located on the pressurized-side of a circular sealing element which seals off the cylinder base from the cylinder housing. The bayonet connection is thereby protected from the entry of detrimental environmental influences, especially dirt and moisture, and it can still be easily disassembled at all times.

Abstract: A fail-safe mechanism for closing the rams in a conventional blowout preventer. The mechanism includes a ram shaft having an enlarged outer end that is exposed to well pressure which exerts a constant closing force. The closing force is opposed by a hydraulic fluid chamber which is evacuated in the event of fire, etc. A floating plug within the ram shaft helps prevent leaks of well fluid from the blowout preventer.

Abstract: A fluid actuator having a piston, a pair of springs, a pair of cams, and a pair of cam followers mounted in a housing. A normally open valve is coupled to the actuator output shaft for actuation. When fluid pressure is applied to the piston, the springs are compressed, and the cam followers are moved down to permit the cams to rotate away from each other, thereby reducing the force on the actuator output shaft and permitting the valve to open. When fluid pressure is removed from the piston, the springs expand pushing the piston and the cam followers up, thereby rotating the cams toward each other and forcing the actuator output shaft against the valve stem to close the valve.

Abstract: An improved spring brake construction is formed by a pair of concave metal housng portions having peripheral lips. Once the internal components of the spring brake are assembled within the housing portions, the lip of one housing portion is spun over the lip of the other housing portion to capture and grip it, thereby permanently sealing the housing portions together. The push rod and coil spring within the spring brake are maintained in axial alignment by a central indentation in one of the housing portions that extends coaxially within the coil spring, and by the construction of the spring diaphragm with a central axial protrusion which extends into a central opening in a spring plate on the side of the diaphragm facing the coil spring. On the opposite side of the diaphragm a push rod seat is laterally restrained from movement relative to the diaphragm.

Abstract: A brake adjuster wherein a thrust block is axially slidable in a cylinder bore and rotatably connected to one of two screw threaded adjuster members which are themselves interconnected by a self-sustaining thread. In use a power spring acts on the thrust block to move it axially within the cylinder bore to apply pressure to a friction pad via the adjuster members. The brake may be released by applying hydraulic pressure to the thrust block, at which time one adjuster member is rotated via a clutch, when a predetermined clearance has been taken up, relative to the other to adjust for pad wear. No relative adjustment occurs during application of the brake under the action of the power spring.

Abstract: A spring brake assembly having a body portion in which a piston is mounted for reciprocal movement. A piston guide means engages a stem portion of the piston and an end of the body portion. A brake spring is caged between an inner surface of a face portion of the piston and an end of the body portion. Engageable at one end thereof with the stem portion of the piston is a pushrod which also extends coaxially out of the end of the body portion. A clutch including control and operating devices is provided.

Abstract: A sensing means is provided to indicate an operating condition of a spring brake cylinder assembly in which such operating condition may be one of a brake applied and a brake release position. The sensing means engages a clutch control mechanism which includes means to engage the sensing means at different locations to make a determination of such operating condition.

Abstract: An air brake includes a service brake chamber which actuates a push rod. A collet brake chamber is partially defined by a collet brake diaphragm. A locking collet is mounted to the collet brake diaphragm and includes a bore through which the push rod passes. A collet brake spring biases the collet into a tapered collet hole to clamp the collet onto the push rod to prevent the movement of the push rod toward the brake off position. Application of pressure to the collet brake chamber overcomes the force of the collet brake spring and moves the collet away from the tapered collet hole to allow the push rod to move freely. Excessive force on brake drums, caused by cooling and contracting brake drums while parked, can be reduced by permitting the collet and push rod therewith to deflect when such excessive force occurs.