Patent GB-190224936-A (GB)
Title: Improvements in Cam Driving Gear
Inventor: HARTMANN WILHELM
Filed: 1902-11-13
Granted: 1903-10-01
Abstract: 24,936. Hartmann, W. Nov. 13. Cam mechanism.-Relates to cam driving-gear of the type described in Specification No. 13,535, A.D. 1902, and stated therein to be for interrupting a reciprocating motion at regular periods as required in steering-gear, valve gear for steam engines, pumps, machine tools, and other apparatus. The reciprocating motion of an intermediate piece on fixed or elastically-yielding rolling tracks is converted into the required interrupted motion According to the former Specification, complete pairing is effected between the transmitting-piece and the fixed piece by forming enclosing-tracks in the body. In Figs. 1 and 2 are shown two other kinds of pairing, consisting in arranging a piece d kinematically similar to the transmitting-piece, or forming generating and directing curves for producing the required tracks of a point 4 of the transmitting-piece a, operated by means of the rod e. By making the piece c movable, the three kinds of pairing may be used together. The driving-gear consists of the five pieces a, a', b, c, d ; a spring f connects the levers c, c<1> to make one piece, and an adjustable stop g is provided so that the gearing will continue to work if the springs fail. The track of the connecting-point 5 of the pieces a, a' is arranged opposite to the piece c, in such a manner that, in the oscillation of the piece a to the left from the limiting position shown, the point 5 describes a circular arc about the centre 6, while in the oscillation to the right, it describes an arc about the point 4. To permit this motion, the distance 4, 5 is made equal to the distance 5, 6. During the oscillation to the left, motion is transmitted to the element c, c<1>, and during the oscillation to the right, the piece c is at rest relatively to the piece d. The curves 2, 2<1> shown in dotted lines would give rolling motion between the pieces a, c, but, for practical work, a circular are h replaces the curve 2, and the curve h<1> is made to correspond. The piece a<1> carries a solid pin at the point 6, and a guide 6<1> is provided to keep the pin in a rectangular path. The curve 7<1> has a radius double that of the curve 7. In operation, when the piece a turns to the left about the point 4, the piece c turns to the right about the point 3, and the point 1 describes a circular arc. The piece a<1> oscillates about the point 6. In the return movement, the piece c first moves to the left and then comes to rest, while the surface 7 rolls on the surface 7<1>. In the arrangement shown in Fig. 2, the track of the point 5 is so arranged relatively to the piece a that, in the oscillation of the piece a to the left, the track is a circular arc of any radius with the centre on the line 5, 6, while, in the oscillation to the right, the track is a circular arc about the point 4. The point 6 is guided in a straight line, and two pairs of curves 8, 8<1> and 7, 7<1> are provided to come into operation, respectively, when the piece c moves to the right, and when, in the return movement, it comes to rest. The path of the point 5 during the motion of the piece c may be straight, or curved towards the opposite side to that shown, provided the path is tangential to the circular arc about the centre 4, in which the point 5 moves while the piece c is at rest. In the modifications shown in Figs. 3 and 4, the generating and directing curves are replaced by concentric circular arcs 2<h>, 7<h>, which touch the pin eyes or sockets on the pieces a, d. The corresponding enclosing-curves are circular arcs concentric with the generating and directing curves. All the forms given in the prior Specification referred to may be similarly modified.