COLLISION SENSOR FOR FENDER BUMPER OPERATED VEHICLE SAFETY DEVICE

• US 3,853,199 A
• Filed: 11/30/1972
• Issued: 12/10/1974
• Est. Priority Date: 11/30/1971
• Status: Expired due to Term

• Current Assignee: Kenzo Hirashima, Shunji Matsui, Yoshikazu Hayakawa
• Original Assignee: Kenzo Hirashima, Shunji Matsui, Yoshikazu Hayakawa
• Inventors: Hayakawa, Yoshikazu, Hirashima, Kenzo, Matsui, Shunji
• Primary Examiner(s): Scott, James R.
• Application Number:
  US05/310,943
• Time in Patent Office: 740 Days
• Field of Search: 200/61.45R,61.53,6,16A,61.08,159A,166C,166BA 335/205,206 180/91-97,103,104 280/15AB 293/4
• US Class Current: 180/274
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: H01H 3/24 using pneumatic or hydraulic actuator for storing energy in a spring motor H01H3/301
• CPC Class Codes: H01H 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002
• CPC Class Codes: H01H 35/146 operated by plastic deformation or rupture of structurally associated elements
• CPC Class Codes: H01H 36/0006 Permanent magnet actuating reed switches H01H35/147 takes precedence

Abstract

An impact-responsive switch mounted on a shock-absorbing bumper and having a housing for a bore. An elongate retractable member is axially slidably mounted in the bore to retract to open or close two contacts provided therein when subjected to a collision impact. The elongate retractable member has attached thereto a permanent magnet which, in the retracted position, applies an attractive or repulsive force tending to close or open the two contacts which are hermetically sealed within an evacuated glass tube to prevent degeneration of the contacts. The impactresponsive switch is so positioned on the bumper that the elongate member is subjected to the collision impact upon compression of a resilient member which is interposed between a back plate of a buffer bar and an end plate of a piston rod forming a part of the bumper mechanism.

Claims

1. In a motor vehicle having a safety device actuable in response to a collision signal, at least one shock absorbing bumper, which bumper includes an impact receiving member extending crosswise horizontally of the vehicle, a cylinder disposed longitudinally of the vehicle and secured to the vehicle'"'"''"'"'s body, a piston axially slidable in a bore of the cylinder, a piston rod extending externally from the piston and having one end secured to the impact receiving member, the piston rod being adapted to be withdrawn into the cylinder when said impact receiving member deforms upon collision against a solid obstacle, and a resilient member disposed between the impact receiving member and the piston rod to partially absorb an impact resulting from a collision, a collision signal producing apparatus comprising, in combination, a normally closed, vehicle deformation responsive switch forming part of a first electric circuit, said deformation responsive switch including an insulated housing mounted adjacent said resilient member and disposed on said one end of the piston rod, the housing defining a cavity formed therein, means defining aligned niches in said one end of said piston rod and said resilient member and lying adjacent said insulated housing, an elongate actuating member axially slidably mounted in the cavity and extending externally of said housing, said elongated actuating member being arranged to normally extend through said niche in said one end of said piston rod into said niche formed in said resilient member but to be withdrawn into said housing upon compression of the resilient member resulting from the collision, a fixed contact disposed in said cavity, and a movable contact which is associated with said elongate actuating member, disposed in said cavity and normally held in contact with the fixed contact, the movable contact being movable to disengage from the fixed contact in response to the withdrawal movement of said elongate actuating member to open said first electric circuit;

and a normally open, inertia responsive switch forming part of a second electric circuit connected with the safety device for producing the collision signal upon closure thereof, said inertia responsive switch including, an insulated housing mounted on the vehicle body adjacent to said impact receiving member, the housing defining a cavity therein, an inertia-responsive magnetic weight located in said cavity for movement in a longitudinal direction of the vehicle body in response to the inertia applied to the body during the collision, a movable contact disposed on said inertia weight, a fixed contact disposed in said housing adjacent to the movable contact, the fixed contact being positioned in a path of the inertia responsive movement of said inertia weight, means applying a force to usually hold said movable contact apart from said fixed contact, the force being overcome by the inertia force at a predetermined degree, and electromagnetic means mounted in the cavity of said inertia responsive switch housing and situated adjacent to the inertia weight on the side opposite to the position of said fixed contact to exert, upon energization thereof, an attractive force upon said inertia weight to hold the movable contact apart from said fixed contact, said electromagnetic means being connected with the first electric circuit and adapted to be deenergized upon opening of said first electric circuit;

whereby said movable contact of the inertia weight is allowed to engage with the fixed contact at a predetermined degree of collision which is enough to open said vehicle deformation responsive switch, only by overcoming the force of said force applying means to close said second electric circuit.

2. An apparatus according to claim 1, in which said movable contact of the deformation responsive switch is disposed on the inner end of said elongate actuating member.

3. An apparatus according to claim 2, further comprising means to keep said elongate actuating member at its extended position.

4. An apparatus according to claim 3, in which said means to keep said elongate actuating member at its extended position is a spiral spring disposed between a wall of said cavity and said elongate actuating member and preloaded to urge the actuating member toward the extended position.

5. An apparatus according to claim 3, in which said means to keep said elongate actuating member at its extended position is plate spring having one end fixed to a wall of said cavity and preloaded to urge the actuating member toward the extended position.

6. An apparatus according to claim 3, in which said means to keep said elongate actuating member at its extended position is a permanent magnet disposed on said housing to exert an attractive force upon said movable contact on said actuating member to urge it toward the extended position.

7. An apparatus according to claim 2, in which said fixed contact of the deformation responsive switch is a tubular member of glass coated thereon with an electrically conductive material and disposed in contact with said movable contact, said tubular member being adapted to be broken by said actuating member when said actuating member is withdrawn thereby cutting off the electric connection of said movable contact with said fixed contact.

8. An apparatus according to claim 1, in which said deformation responsive switch further comprises a permanent magnet provided on said elongate actuating member.

9. An apparatus according to claim 8, in which said movable contact and said fixed contact of the deformation responsive switch form a reed enclosed in a fluid-tight tube disposed adjacent to said permanent magnet.

10. An apparatus according to claim 1, in which said cavity of said housing of said deformation responsive switch is divided into a first compartment and a second compartment by a partition member, and accommodates therein a piston secured to the inner end of said elongate actuating member, said piston being axially slidable in the first compartment, and a bellows member provided within the second compartment and communicating with the first compartment through an opening formed in the partition member, and in which said movable contact is disposed on the bellows member for movement therewith and said fixed contact is provided in the second compartment normally in contact with said fixed contact by a tension spring, whereby upon compression of said bellows member, said movable contact is removed from said fixed contact.

11. An apparatus according to claim 1, in which said inertia weight of the inertia responsive switch is of a pendent type hanging from the top wall of the housing by a flexible wire.

12. An apparatus according to claim 11, in which said force applying means is a permanent magnet disposed adjacent to said inertia weight on the side opposite to the position of said fixed contact.

13. An apparatus according to claim 1, in which said force applying means is a spring within said cavity extending in the longitudinal direction of the vehicle and having one end anchored to the movable contact on said inertia weight to urge it toward the electromagnetic means.

14. An apparatus according to claim 13, in which said inertia weight is a spherical member held in position by said spring.

15. A collision sensor for sensing a collision condition of a motor vehicle to actuate a safety device mounted thereon, said collision sensor being mounted on a shock-absorbing bumper which includes an impact receiving member extending crosswise horizontally of the vehicle, a cylinder extending longitudinally of the vehicle and secured to the vehicle'"'"''"'"'s body, a piston axially slidable in the cylinder, a piston rod extending externally from the piston and connected with the impact receiving member, and a resilient member provided on the impact receiving member to partially absorb an impact resulting from a collision, said collision sensor comprising:

a housing having a bore formed therein;

an elongate actuating member axially and slidably mounted in the bore and extending externally of said housing, said elongate actuating member being arranged to normally extend into a niche formed in the resilient member but to be retracted into said housing upon compression of the resilient member resulting from a collision;

biasing means for normally biasing said elongate actuating member to its extended position;

switch means provided in said housing for actuating the safety device when said elongate actuating member is forcibly moved to its retracted position, said housing having a chamber divided into first and second compartments by a partition member; and

said elongate actuating member has a piston secured to the inner end thereof, the piston being axially slidable in the first axial compartment; and

a bellows member is provided within the second compartment and communicates with the first compartment through an opening formed in the partition member; and

said switch means comprises a movable contact secured to the bellows member for movement therewith, and a fixed contact provided in the second compartment; and

said biasing means comprises a spring provided between the partition member and the movable contact to normally keep the bellows member in a contracted condition, the movable contact being kept in contact with the fixed contact when the bellows member is contracted.