Patents by Inventor David Howard Kerr

David Howard Kerr has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8119940
    Abstract: The present invention includes a contact block for a safety switch that has a support structure and a pair of electrical contacts that are fixed in position on the support structure. The contact block includes a contact block plunger provided with a bridging contact. The bridging contact extends through the contact block plunger, from one side to another, and protrudes from the sides of the contact block plunger. The contact block plunger is moveable in-between the fixed pair of electrical contacts to move the bridging contacts into and out of contact with the fixed pair of electrical contacts. A contact block guide extends along the support structure and between the pair of fixed electrical contacts and cooperates with the contact block plunger such that the contact block plunger is restricted to movement along the contact block guide.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: February 21, 2012
    Assignee: Rockwell Automation Limited
    Inventor: David Howard Kerr
  • Patent number: 7928330
    Abstract: There is provided a safety switch having a housing configured to receive a removable key, and a mechanism arranged to be operated when the key is moved from an engaged position to a partially disengaged position, the mechanism being arranged to cause a signal to pass to a separate apparatus, wherein the safety switch further comprises a lock which is controlled by the separate apparatus and is arranged to prevent the key from being fully disengaged from the safety switch until a signal has been received in response from the separate apparatus.
    Type: Grant
    Filed: September 29, 2006
    Date of Patent: April 19, 2011
    Assignee: Rockwell Automation Limited
    Inventors: Julian Poyner, David T. Williams, Gillian P Parker, David Howard Kerr, Derek W Jones, Derek Sawyer, Geoffrey Alan Talbot, William E Anderson, Michael R. Scharnick, Stephen Zbytowski
  • Patent number: 7800004
    Abstract: A safety switch plunger includes a moveable conductor which extends transversely through the plunger and protrudes from opposite sides of the plunger. The plunger is provided with a structure that is positionally fixed on the plunger. The structure is positioned such that it is arranged to come into physical contact with and affect the movement of the moveable conductor when the moveable conductor and plunger are moved relative to one another thereby providing a fail-to-safe safety switch.
    Type: Grant
    Filed: June 7, 2007
    Date of Patent: September 21, 2010
    Assignee: Rockwell Automation Limited
    Inventor: David Howard Kerr
  • Patent number: 7724112
    Abstract: A safety switch that includes a locking mechanism having a rod locking element that is located adjacent to a rod and engageable with the rod to lock the rod in position relative to a housing. The safety switch locking mechanism includes a locking member that is moveable relative to the housing in response to a difference in inertia between the locking member and the housing when a force is applied to the housing. The locking member is arranged to inhibit disengagement of the rod-locking element from the rod when the force is applied to the housing.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: May 25, 2010
    Assignee: Rockwell Automation Technologies, Inc.
    Inventor: David Howard Kerr
  • Publication number: 20080257696
    Abstract: The present invention includes a contact block for a safety switch that has a support structure and a pair of electrical contacts that are fixed in position on the support structure. The contact block includes a contact block plunger provided with a bridging contact. The bridging contact extends through the contact block plunger, from one side to another, and protrudes from the sides of the contact block plunger. The contact block plunger is moveable in-between the fixed pair of electrical contacts to move the bridging contacts into and out of contact with the fixed pair of electrical contacts. A contact block guide extends along the support structure and between the pair of fixed electrical contacts and cooperates with the contact block plunger such that the contact block plunger is restricted to movement along the contact block guide.
    Type: Application
    Filed: February 28, 2008
    Publication date: October 23, 2008
    Inventor: David Howard Kerr
  • Publication number: 20080078658
    Abstract: There is provided a safety switch having a housing configured to receive a removable key, and a mechanism arranged to be operated when the key is moved from an engaged position to a partially disengaged position, the mechanism being arranged to cause a signal to pass to a separate apparatus, wherein the safety switch further comprises a lock which is controlled by the separate apparatus and is arranged to prevent the key from being fully disengaged from the safety switch until a signal has been received in response from the separate apparatus.
    Type: Application
    Filed: September 29, 2006
    Publication date: April 3, 2008
    Applicant: EJA LIMITED
    Inventors: Julian Poyner, David T. Williams, Gillian P. Parker, David Howard Kerr, Derek W. Jones, Derek Sawyer, Geoffrey Alan Talbot, William E. Anderson, Michael R. Scharnick, Stephen Zbytowski
  • Publication number: 20080023307
    Abstract: A safety switch plunger includes a moveable conductor which extends transversely through the plunger and protrudes from opposite sides of the plunger. The plunger is provided with a structure that is positionally fixed on the plunger. The structure is positioned such that it is arranged to come into physical contact with and affect the movement of the moveable conductor when the moveable conductor and plunger are moved relative to one another thereby providing a fail-to-safe safety switch.
    Type: Application
    Filed: June 7, 2007
    Publication date: January 31, 2008
    Inventor: David Howard Kerr
  • Publication number: 20080006116
    Abstract: A safety switch that includes a locking mechanism having a rod locking element that is located adjacent to a rod and engageable with the rod to lock the rod in position relative to a housing. The safety switch locking mechanism includes a locking member that is moveable relative to the housing in response to a difference in inertia between the locking member and the housing when a force is applied to the housing. The locking member is arranged to inhibit disengagement of the rod-locking element from the rod when the force is applied to the housing.
    Type: Application
    Filed: May 4, 2007
    Publication date: January 10, 2008
    Inventor: David Howard Kerr