Patent GB-458779-A (GB)
Title: Improvements in electrically-tripped or released switches
IPC: H01H71/52
Filed: 1935-06-26
Abstract: 458,779. Electrically-tripped switches. COX, F. B., 65, Fleet Street, Liverpool. June 26, 1935, No. 18247. [Class 38 (v)] Relates to switches of the kind in which a setting part by the first movement of a handle is moved against the action of gravity or a spring into the position it occupies when the switch is closed, and is held in this position against the action of gravity or the spring, by a detent or the like controlled by a no-volt, overload, or like automatic device, and a closing part which, by said first movement of the handle, is moved into a position in which the respective contacts of the two parts remain separated, the second and reverse movement of the handle, which occurs without effecting movement of the setting part, moving the closing part into a position in which a contact carried thereby engages a contact on the setting part to close the switch. Consists in that one of the said parts comprises two relatively movable contact-members and the other part comprises a movable contact-member adapted in the closed position of the switch to bridge the two contact-members of the other part. In Fig. 1, anticlockwise rotation of H causes the lever h<2> to lift the slotted link h<3>, so that the part A is lifted by the pin 32 into a position where the extension 35 is latched by the no-volt controlled detent 16. By means of levers h<1> and links h<4>, the closing parts B, B<1> are rotated about pivots b, b<1> so that contacts 13 move away from contact 12. On reverse rotation of H, the contacts 13 engage opposite sides of 12 and the parts are held closed by the toggles h<1>, h<4> being slightly overset. An overload coil 19 is also provided. The pin-and-slot arrangement may be replaced by a cam or toggle. Fig. 4 shows an arrangement for automatically tripping the switch if an attempt is made to open it by rotation of the handle, the contacts 40, 42 being arranged in the no-volt coil circuit. Contact 40 is pivoted at 41 and urged by spring 44<a> into the closed position. It carries a flexible steel strip 44 which is deflectible by a pin 46 on the operating handle when returning to normal position, but if moved back therefrom it opens the contact 40. In a three-phase switch, the three setting members A are carried on a frame which is guided at 91, 92 for vertical movement and carries a pin at each end engaging in a slot 96 in a pair of levers 93, 94 pivoted at 95. The shaft h of handle H is connected to the levers by a lever h<2> pivoted at h<1> to a link h<3>, slotted to engage a pin 32 on lever 93, so that when rotated anticlockwise, the end 93<a> is raised to engage latch 16 to maintain it set. The members B, B<1> are linked at h' to a lever 100 fast on shaft h. In this form an overload coil in each phase operates a trip bar which opens a switch in the circuit of a no-volt coil 98. When the latter is de-energized either by overload or loss of voltage, an armature 97 loose on shaft h rotates, and by means of cam 99 deflects the latch 16. The armature 97 is raised during closure by means of the pivot h<6>. To avoid possibility of opening the switch by a backward movement of the handle, a toothed member 84 on shaft h is adapted to engage a slider 85, which engages a depending part 86 on a member 87 secured to the trip bar, a manual trip button 81 being also provided. When member A is held by a detent, the trip bar can be arranged to operate the detent to release the member A. The handle H may be retained by a trippable detent, and members B, B<1> may be arranged to be retained set by the first movement of the handle and released by the second movement of the handle to effect a quick closure.